April 10, 1993
I I
Efwirori mental
40 CFR Parts 122 et al.
Water Quality Guidance for the Great
Lakes System and Correction; Proposed
flutes-."- ,..:- .'..';. ; ":" -.' '•• '•'•-_•'. .--":::"-: .':" •'-: "'-
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20802
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 122, 123, 131, and 132
filN2MO-AC08
Proposed Water Quality Guidance for
the Great Lakes System
AGENCY: U.S. Environmental Protection
Agency.
ACTION: Proposed rule.
SUMMARY* This document provides
opportunity for comment on the
proposed Wator Quality Guidance for
tha Groat Lakes System ("Guidance")
developed under section 118(c)(2) of the
Clean Water Act (CWA), as amended by
section 101 of thS Great Lakes Critical
Programs Act of 1990 (CPA). This
Guidance, once finalized, will establish
minimum water quality standards,
antidegradation policies, and
implementation procedures for waters
within the Great Lakes System in the
States of New York, Pennsylvania, Ohio,
Indiana, Illinois, Minnesota, Wisconsin,
and Michigan, including the waters
within the jurisdiction of Indian tribes,
Today's proposal also is intended to
satisfy tho requirements of section
118(c)(7)(C) of the Clean Water Act that
EPA publish information concerning the
public health and environmental
consequences of contaminants in Great
Lakes sediment and that the information
include specific numerical limits to
protect health, aquatic life, and wildlife
from tho bioaccumulation of toxins.
The proposed Guidance specifies
numeric criteria for selected pollutants
to protect aquatic life, wildlife and
human health within the Groat Lakes
System and methodologies to derive
numeric criteria for additional
pollutants discharged to these waters.
*Tho proposed Guidance also contains
specific implementation procedures to
translate the proposed ambient water
quality criteria into enforceable controls
on discharges of pollutants, and a
proposed antidegradation policy for the
Groat Lakes System.
The Great Lakes States and Tribes
must adopt water quality standards,
antidegradation policies, and
implementation procedures for waters
within the Great Lakes System which
arc consistent with the final Guidance.
If a Groat Lakes State or Tribe fails to
adbpt consistent provisions within two
yoars of EPA's publication of the final
Guidance, EPA will promulgate such
provisions within the, same two-year
period.
DATES: EPA will accept public
comments on the proposed Guidance
until September 13,1993. Comments
postmarked after this date may not be
considered. •
A public hearing on the proposed
Guidance will be held on August 4 and
5,1993, in Chicago, Illinois, beginning
at 9 a.m. on August 4,1993. The hearing
officer reserves the right to limit oral
testimony to 10 minutes, if necessary.
In addition, EPA and lie States plan
to hold a series of public informational
meetings across the Great Lakes Basin to
provide a general overview of the
various elements in the proposed
Guidance, Members of the public
should call the following numbers for
information on the dates and locations
'of these meetings: (1) In Illinois,
Indiana, Michigan, Minnesota, Ohio and
Wisconsin—800-621-8431; (2) in
Pennsylvania—215-597-6911; (3) in
New York—716-285-8842.
ADDRESSES: An original and 4 copies of
all comments on the proposed Guidance
should be addressed to Wendy
Schumacher, Water Quality Branch
(WQS-16J), U.S. EPA, Region V, 77
West Jackson Blvd., Chicago, Illinois,
60604 (telephone: 312-886-0142).
The public hearing on the proposed
Guidance will be held in room 331, 77
W. Jackson Blvd., Chicago, Illinois.
Materials in the public docket will be
available for inspection and copying at
the U.S. EPA Region V Records Center,
77 W. Jackson Blvd., Chicago, Illinois,'
by appointment only. Appointments
may be made by calling Wendy
Schumacher (telephone 312-886-0142).
A reasonable fee will be charged for
photocopies.
Selected documents supporting the
proposed Guidance will also be
available for viewing by the public at ,
the following locations:
Illinois: Lincoln Library, Lincoln Library
Reference Center, 326 South 7th Street,
Springfield, Illinois, 62701 (217-753-
4945).
Indiana: Indiana Department of
Environmental Management, Office of
Water Management, 6th Floor, 105
Meridian Street, Indianapolis, Indiana,
46206 (317-232-8671).
Michigan: Library of Michigan, Government
Documents Service, 717 West Allegan,
Lansing, Michigan, 48909 (517-373-1300);
Detroit Public Library, Sociology and
Economics Department, 5201 Woodward
Avenue, Detroit, Michigan, 48902 (313-
833-1440).
Minnesota: Minnesota Pollution Control
Agency, Library, 320 Lafayette, St. Paul,
Minnesota (612-296-7719).
New York: U.S. EPA Region II Library, room
402, 26 Federal Plaza, New York, New
York, 10278 (212-264-2881); U.S. EPA
Public Information Office, Carborundum
Center, Suite 530, 345 Third Street, Niagara
Falls, New York, 14303 (716-285-8842);
New York State Department of
Environmental Conservation (NYSDEC),
room 310,50 Wolf Road, Albany, New
York, 12333 (518-457-7463); NYSDEC,
Region 6, 7tH Floor, State Office Building,
317 Washington Street, Watertown, New
York, 13602 (315-785-2513); NYSDEC,
Region 7, 615 Erie Boulevard West, s
Syracuse, New York, 13204 (315-426-
7400); NYSDEC, Region 8, 62 74 East ,
Avon-Lima Road, New York, 14414 (716-
226-2466); NYSDEC, Region 9, 270
Michigan Avenue, Buffalo, New York,
14203(716-851-7070).
Ohio: Ohio Environmental Protection Agency
Library—Central District Office, 1800
Watermark Road, Columbus, Ohio, 43215
(614-644-3024); U.S. EPA Eastern District
Office, 25809 Central Ridge Road,
Westlake, Ohio, 44145 (216-522-7260).
Pennsylvania: Pennsylvania Department of
Environmental Resources, 1012 Water
Street, Meadville, Pennsylvania, 16335;
U.S. EPA Region III Library, 8th Floor, 841
Chestnut Building, Philadelphia,
Pennsylvania, 19107-4431 (215-597-
7904).
Wisconsin: Water Resources Center,
. University of Wisconsin-Madison, 2nd
Floor, 1975 Willow Drive, Madison,
Wisconsin (608-2620-3069).,
Selected documents supporting the
proposed Guidance are also available by
mail upon request for a fee (see section
Xm of the preamble for additional
information).
FOR FURTHER INFORMATION CONTACT:
Kenneth A. Fenner, Water Quality
Branch Chief (WQS-16J), U.S. EPA
Region V, 77 W. Jackson Blvd., Chicago,
Illinois, 60604 (Telephone: 312-353-
2079).
SUPPLEMENTARY INFORMATION:
Preamble Outline
I. Background
A. Description of Resource
1. General Statistics . : '
2. Physical Characteristics
3. History of Environmental Degradation
4. Environmental Problems in the Great
Lakes System '._"..
a. Nutrients ,
b. Toxic Substances .
B. Great Lakes Water Quality Agreement
1. History of the Great Lakes Water Quality
Agreement '
a. The Boundary Waters Treaty of 1909
b. The 1972 Great Lakes Water Quality
Agreement -
c. The 1978 Great Lakes Water Quality
Agreement "'
d. The 1987 Amendments to the Great
Lakes Water Quality Agreement
2. Major Provisions of the Great Lakes Water
Quality Agreement
3. Implementation of the Great Lakes Water
Quality Agreement
a. The International Joint Commission
b. Provisions for Consolidation and Review
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Federal Register / Vol. 58, No. 72 / Riday, April 16, 1993 /Proposed Rules, 3I&803'
c. Status of Negotiations With Canada on
- Revising the Specific Objectives
C. Governors' Toxics Agreement
D. Great Lakes Water Quality Initiative
1 Formation of Great Lakes Water Quality
mitiative /
2. Great Lakes Critical Programs Act of 1990
.3. Process After the CPA
E Elements of the Guidance
1 Water Quality Criteria for the Protection of
Aquatic Life
2-.Water Quality Criteria for the Protection of
Human Health - ,
3 Water Quality Criteria for the Protection of
Wildlife :..""• ' •'..;. - ' • ; :
4. Bioaccumulation Factors : -
5. Antidegradation !
'• 6. Implementation Procedures
-F. Science Advisory Board Review
G. Other Programs to Protect and Restore the
Great Lakes •••/''*' '.'-.
1. Great Lakes Five Year Strategy ;
2. Great Lakes Pollution Prevention Action
Plan
3. Lake wide Management Plans (LaMPs)
4. Remedial Action Plans CRAPs) . --".'"
5. Contaminated Sediments '
6. Atmospheric Deposition ' ' . '.-•• '_•
7. Storm Water : • ' ,
8. Combined Sewer Overflows (C£!Os)
9. Discharges of Oil and Hazardous Polluting
, Substances ; -
10. Nonpoint Sources of Pollution
111 Great Lakes Fish Advisories
12. Environmental Monitoring and Data •' .,.
Management Programs for the Great
Lakes . . .' ... :'..,' v. . .. ••.' . ••
13. Great Lakes Toxic Reductions Initiative
•• Multi-media Management Committee
H. References
II. Regulatory Requirements . ;
A. Scope and Purpose ".-.-- L .
B. Definitions -. ;•;'.' .- .'
C. Adoption of Criteria. Methodologies, and
Procedures "
D. Application'of Methodologies, Policies,
and Procedures ,.
1. The Two-Tiered Approach •
2. Application of Tier I Methodologies ,
3. Application of Tier n Methodologies
E. Applicability of the Water Quality
Guidance
1. Criteria and Values -" •'''• ;
a. Background ' -
b. Applicability of the Proposed Guidance
c. Justification for the Proposed. Approach
• d. Other Options Considered ••'—
2. Implementation Procedures .
a. Applicability of the Proposed Guidance
b. Justification for the Proposed Approach
i. Wet-weather Point Source Discharges
,ii. Excluded Pollutants ->.
3. Antidegradation Policies ,:
. F. Excluded Pollutants ,
G. Pollutants of Initial Focus fo'r Criteria
Development, and Bibaccurnulative ;
Chemicals of Concern .. ., ^_
H. Adoption Procedures ' '.
I. Interpretation of "Consistent With"
j; Precedential Effect of Elements of the
Guidance
K. Endangered Species Act <
L. Request for Comments ;
m. Aquatic Life
A. Introduction and Purpose . , .
B. Tier I Criteria ' " . '' :
1. Methodology '.-.-'
. 2. Selection t>f Pollutants for Application of
.'. Tier I Criteria Methodology ; "
3. Tier I Numeric Criteria ,
4. Potential Changes to National Guidelines
C. Tier II Values ; >
D. Confbrmance to the Clean Water Act,
Great Lakes Water Quality Agreement and
Great Lakes Critical Programs Act of 1990
1. Tier I Aquatic Life Criteria and
Methodology .. ;
a. Comparison With the Clean Water Act
b. Conformance With the Great Lakes
Water Quality Agreement
2. Tier H Criteria Methodology
a. Comparison With the Clean Water Act
b. Conformance With the Great Lakes •
Water Quality Agreement
TV. Bioaccumulation Factors : : -.'•- "••
A. mtroduction • " ' .-'-•
B. Bioaccumulation Factors
1. Bioaccumulation and Bioconcenbation •
Concepts '.•-'. .'--'-
2. Existing EPA Guidance
3. The Great Lakes Guidance for BAFs "
a..Measured and Predicted BAFs . '
b. Standard Lipid Values
i. Standard Lipid Value for Human Health
BAFs ' ' ". ' : .-
ii. StandardLipid Value for Wildlife BAFs
iii. Comments Requested
c. Food Chain Multipliers
d. EHect of Metabolism on BAFs
e. Bioavailability . ,
f. Other Uses of BAFs
4. SAB Comments
5. Relationship of the Guidance to Current
; EPA Guidance
6. Adoption of Water Quality Standards ',
Consistent with the Proposed Guidance
7, Literature Cited , •"
V. Human Health ~ ; r
A.,Jntroduction , : "-',.•'._••
.B. Criteria Methodologies
1. Endpoints Addressed by the Human
Health Methodologies
2. Mechanism of Action: Cancer and
Noncancer '.''•'
a. Cancer ,
b, Noncancer ..
_3. Choice of Risk Level r '
4; Acceptable Dose -
a,RAD
•' C.IRIS- " •••••••••; - .- ;•;••• v '_:\ ::c^-r::-:'
"5. Exposure Assumptions ;"-<-X' •
a.,Body Weight _: - __
• b. Duration of Exposure' ' • ' r
; c. Incidental Exposure >_, . .
d. Drinking Water Consumption
'e.' Fish Consumption , , .
f. Bioaccumulation Factor (BAFJ
' g. Relative Source .Contribution '
h^ General Considerations
6. MmimumData,Requkements/TierIand
' Tiern : ; .,, ; .' '• . _ ,
a. Carcinogens ,
b. Non-carcinogens ' . v
7. Criteria Derivation : •,-•'-•-
8, Proposed Criteria and Values' ;
G. Relationship of the Great Lakes Initiative
Guidelines to National Guidelines Revisions
D. Comparison With the Clean Water Act and
Great Lakes Water Quality Agreement
1. Tier I Human Health Criteria/Methodplpgy
a. Comparison With the Clean Water Act
b. Conformance With the Great Lakes , ~
, Water Quality Agreement "
2. Tier H Criteria Methodology ' "- * "" ""
a. Comparison with the Clean Water Act i.
b. Conformance with the Great Lakes Water
Quality Agreement . ' ; /
E. Review of the Great Lakes Guidance by the
EPA Science Advisory Board (SAB)
F. Literature Citations ••{-. -
vi.
A, Introduction "
B. Wildlife Criteria Methodology .
l.Wisconshi State. Wild and Domestic
Anknal Criteria : ;
2. Modifications to Wisconsin's WDAC -
, Procedure : ' ': • ' i- ;
3. The'Great Lakes Water Quality Initiative
TOdlife Criteria Methodology {
a. Parameters of the Hazard Component of
the GLWQI Wildlife Criteria t
Methodology ' '.'-'_ :
i. I0AEL to NOAEL Extrapolations
ii. Subchronic to Chronic Extrapolations
iii. Species Sensitivity Factor ;
iv. intraspecies Variability •'•'••.
v. Alternative Formula for Hazard
Component of Equation
b. Parameters of the Exposure Component
^ of the GLWQI Wildlife Criteria
'._•: Methodology
- i. Approach Used to Select Representative
: Species Identified for Protection
ii. Bioaccumulation Factors
Hi. Exposure Routes Considered
C. Additional Issues -.' • '
l.Use'of Human Health Paradigm ;
2. Minunum Data Base .for Wildlife Criteria/
Derivation :.:. .''.'.. . ' !",,'>
3, Acceptable Endpoints for Toxicity Studies '
4. Use of an Acute to Chronic Conversion1 •'"•".!,
.-' "Ratio- - , :; .• ' '•-••/'.--• - ' :>-, ...' .-••
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Federal Register / Vol. 58, No. 72 / Fr&ay, April 16, 1993 / Proposed Rules
D. Chemical Selection for Wildlife Criteria
Derivation
E. Tier I Wildlifa Criteria and Tier D Wildlife
Values
P. Comparison With the CWA and
Relationship to National Guidance
1. Relationship to Existing National Guidance
2, Relationship to Current Efforts to Provide
National Guidance for the Development
of WOdlifo Criteria
G, Comparison of Wildlife Criteria and
Methods to National Program and to Great
Lakes Water Quality Agreement
1, "No Less Restrictive" Than the CWA and
National Guidance
2, Conformanct With the Great Lakes Water
Quality Agreement
H. Bibliography
VH. Antidegradation
A. General Discussion/Background
1. Federal AnUdegradaUon Policy and
History
I. History of tho Federal AnUdegradation
Policy
b. Existing National Antidegradation Policy
c. Great Lakes States Experience
d. Alternative Approaches to Assessing
Lowering of Water Quality
B. General Outline of GLWQI
AnUdegradation Process
1, NarraUvo Flow Chart of Process
2. Preconditions for Implementation of
AnUdegradation Procedures
3. Steps Preceding an AnUdegradaUon
Review
a. Establish That the Action May
SJgnificanUy Lower Water Quality
b. Characterize the Receiving Water
C AcUviUes Covered by the Great Lakes
AatidegradaUon Guidance
1. DistlncUon Between High Quality Waters,
Outstanding National Resource Waters,
and Other Classes of Waters
i. Existing Federal Policy
b. GLWQI Guidance
2. Significant Lowering of Water Quality
3. Covers All Pollutants Sources (Point and
Nonpoint)
4. Exemptions
5. Discharges of Fill Material in Wetlands
D. Existing Effluent Quality
1, Background
2, OpUon 3 for EEQ Controls
a, Option 1: EEQ as Numeric Mass Loading
Rate Limitations
b. OpUoa 2: NarraUve Prohibition Coupled
* with EEQ NotificaUon Requirement
c. Supplement to Options 1 or 2:
Establishment of Discharge Prohibitions
to Maintain EEQ
3. Issues
a. Punishment of Good Performers
b. Statistical Procedures
c. Data Availability and Representativeness
d. Application to Municipalities
o. Restrictions on Actions Versus
Limitations on Pollutants
f. Statutory Authority for EEQ
g. Ability to Accommodate a Return to
Increased Production Levels Under
AnUdegradaUon.
h. Relationship of EEQ to Implementation
Procedure 8
E. De Minimis Lowering of Water Quality
1. Background , •
2. Detailed Description of De Minimis Test
a. Specific Tests Included in De Minimis ',
Demonstration
b. Examples
i. Example 1
li. Example 2
iii. Example 3
3. Issues
a. Use of Assimilative Capacity in De
Minimis Decision
b. Fixing Assimilative Capacity at a Date.
Certain and Choice of Date
c. Demonstration That No Ambient Change
Occurs as a Result of Increased Loading
d. Use of the Margin of Safety Specified in
the Implementation Procedures as a
Ceiling on De Minimis Decisions
e. Multiple De Minimis Lowering of Water
Quality by a Single Source
F. Antidegradation Demonstration
Components
1. Background and Rationale
2. Hierarchy of Antidegradation
Demonstrations
3. Identification of Prudent and Feasible
Pollution Prevention Alternatives to
Prevent or Reduce the Significant
Lowering of Water Quality
a. Substitution of BCCs with Non-
bioaccumulative and/or Non-toxic
Substances
b. Application of Water Conservation
Methods
c. Waste Source Reductions Within Process
Streams
d. Recycle/Reuse of Waste By-products,
Either Liquid, Solid, or Gaseous
e. Manufacturing Process Operational
Changes
4. Alternative or Enhanced Treatment
Alternatives That Eliminate the
Significant Lowering of Water Quality
5. Social or Economic Development
Demonstration
a. Baseline Situation
b. Net Positive Impact
c. Other Developments •
6. Special Remedial Action Provision
7. Issues
a. Other Options Considered for
Determining if Significant Lowering of
Water Quality is Necessary
b. Economic Recovery
c. Best Available Technology
d. Mandatory Expenditures for Alternative
or Enhanced Treatment Techniques
e. Antidegradation Decision Presumption,
Against the Significant Lowering of
Water Quality
G. Special Antidegradation Provisions for
Lake Superior
1. Background
2. Effect :
a. Relationship to Other Antidegradation
Requirements
i. Example
b. Lake Superior Basin-Outstanding
National Resource Waters . . ;
c. Lake Superior Bioaccumulative
Substances of Immediate Concern
H. Offsets
I. Incorporation Into State Water Quality
Standards .
VIII. Genera! Implementation Procedures
A. Site-Specific Modifications to Criteria ,
B, Variances From Water Quality Standards,
for Point Sources . ' •
1. Current EPA Policy
2. GLWQI Proposal (40. CFR part 132, -
Appendix F, Procedure 2)
3. Applicability - " .
4.' Maximum Tmieframe
5. Conditions to Grant a Variance
6. Timeframe to Submit Application :
7. Public Notice of Preliminary Decision
8. Final Decision on Variance Request
9. Incorporating State- or Tribal-approved
Variance Into Permit
10. Renewal of Variance
11. EPA Approval
12. State or Tribal Water Quality Standards
Revisions
13*. Consistency With the CWA and
Conformance With the GLWQA
a. Consistency With the Clean Water Act
b. Conformance With the Great Lakes
Water Quality Agreement ,
14. Options Considered
15. Request for Comments
C. Total Maximum Daily Loads
1. Background
2. National Approach
a. General Approach to TMDL
Development
b. Phased TMDLs
c. Pollutant Degradation
d. Pollutant Transport
3. Development of the Proposed Guidance
a. The Proposed Guidance
b. Overview of Option A and Option B
4. General Conditions of Application
a. General Condition 1
b. General Condition 2
c. General Condition 3
d. General Condition 4 ,
e. General Condition 5
f. General Condition 6
g. General Condition 7
h. General Condition 8
i. General Condition 9
j. General Condition 10
k. General Condition 11
5. Special Provisions for BCCs
a. Reason for Restricting Discharge of BCCs
b. Elimination of Mixing Zones for BCCs
c. New Sources .;.',.
d. Mixing Zones During the Ten Year
Phase Out
e. Exception to the Ten Year Phase Out of
Mixing Zones
6. TMDLs for Open Waters of the Great Lakes
a. Point Source Mixing Zones for Chronic
' .Criteria and Values
b. Calculating Load Allocations
c. Protection From Acute Effects . .
d. Procedures When High Background
• , Concentration's are Present ', "
e. Margin of Safety
i. Chronic Criteria and Values
ii. Acute Criteria and Values
7, TMDLs for Discharges to Tributaries
a. Steady State Mass Balance Approach
Common to Both Options
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Federal Register / Vol. 58, No. 72/^ Friday. April 16, 1993 /Proposed Rales
20805
b. Design Flows Common ;to Both Options
c. Overview of Option, A ...... /
i. Load Inventory. .,
. ii;Loading Capacity . "
,; iii. Basin Margin Of Safety '._'"
. iv. Load Reduction Targets '"..
v. Basin Allocations .':•'.
vi. Site-specific Cross-checks
vii. Establish Final Allocations
viii. Monitoring Provisions .
d. Overview of Option B '
i. Source-specific TMDLs _ •
ii. Mixing Zone Capacity ; '
iii. Background Loadings ;" -.. . .
iv. Formula Modification Based on Mixing
'Zpne.Studies ,r . ' :,
v. Limitation of Use of Source-specific
TMDLFormula _ , ,
e. Pollutant Degradation ,
8. Pollution Trading Opportunities !
; 9..State Adoption : ,
10. Summary of Other Options Considered
11, Request for Comments
D.Additivity \
1. Introduction " ;_",' ...
2. Approaches Considered : ..
a. Aquatic Life . . , " ..
b. Human Health—Carcinogens
c. Human Health—Non-carcinogens
d. TEFs and BEFs for Chlorinated Dibenzo-
p-dioxins (CDDs) and Chlorinated
Dibenzoforans (CDFs)
e. Wildlife ' ' ; : '
3. Request for Comment on Approach
Considered for Implementing the States'
Narrative Criteria
4. Request for Comment on Alternative ,
Approach :
5. Request for Comments ..'.;•; "
E. Reasonable Potential for Exceeding
Numeric Water Quality, Standards •-.,-.
1. Existing National Rules and Guidance
a. Excursion Above the Water Quality
- Standard : . •••,'•'. .
b. Reasonable Potential for Excursion
Above the Water Quality Standard
c. No Reasonable Potential for Excursions
Above the Water Quality Standards
d. Inadequate information
2. Proposed Procedure 5 - '•'..; • •
a. Develpping Preliminary Effluent
. Limitations, , -'.'-.-' '•.-.'.'
b. Determining Whether There is , ,
Reasonable Potential to Exceed the ,
Preliminary Effluent Limitations "
, i. Determining Reasonable Potential Where
" Ten or More Effluent Data Points are
Available and the Effluent Flow Rate is
, Less than the 7-day, 10-year Flow Rate
. or the Discharge is to Open Waters of the
Great Lakes. , , _.... .
ii. Determining Reasonable Potential
* Where Ten or More Effluent Data Points
are Available and the Effluent FJ6w Rate
is Equal to or Greater Than the 7-day, 10-
; yearFlpwRate . v '•'...-- •
iii. Determining Reaspnable Potential
, , Where There is at Least Onejnit Less
Than Ten Data Points Available
c. Determining .the Need for Water Quality-
based Effluent Limitations in the
Absence of Effluent Monitoring Data for
A Specific Facility -:'; , ••'.','•;'• '.--.-
d. Determination of Reasonable Potential
• : foriPpllutants for Which Great Lakes Tier.
, II Values are Not'Available . -_ • ''•_' -~ •
e. Consideration of Intake Water Pollutants
W^ien Determining Reasonable Potential
, i. Introduction ,
Ii. Current National Approach,
(A) Net/Gross Credits for Technolpgy-based
" ' ' Lunits .;.'•.": ..- •• .-.' ..•.:":' .-'
(B) Consideration of Intake Water .
:; : Pollutants for Water Quality-based
Limits • . - '- •-.--',-• i
• (i)TMDLS•-.'--- . :• .:•-•_•] .-/'..; . :,
'-. (2) Variances From Water Quality
Standards. • ,• .V
" (3) Modifications to Designated Uses
(4) Site-specific Modifications to Criteria
(5) Additional Examples Of Application of
: Existing Mechanisms
iii. Proposed Guidance ."•• -
iv. Alternative Options Considered
(A)Option-l -.: . .;• /' --^'. -' '
(B)Option2 :"-"- '.- ,
(C) Option 3 ;; -r '. '.]''" '
(D)Option4 : .; '
,' v. Request for Public Comment .
f. Other Applicable Conditions
F. Whole Effluent Toxicity - •
l..Bac;kground .
2. Cun-ent National Guidance ; "
a. Regulations
b, Existing Technical Guidance :
3. Great Lakes Guidance
a. WET Basic Requirements' .
i.* Acute Toxicity Control ;
• ii. Chronic Toxicity Control
\iii.NumericandNarrativeCriteria
b. WET.Test Methods
c. Permit Conditions
i. Data Indicates the Reasonable Potential
forWET
ii. Insufficient Data to Determine the
-' Reasonable Potential for WET
iii. Data Indicates No Reaspnable Potential
for WET •''"..
d. Reasonable Potential Determinations
i. Characterizing Acute and Chronic : ,
, Toxicity Values . ".'
ii. Specific Conditions for Acute Toxicity
iii. Specific Conditions for Chronic -
Toxicity . ;
e. State and Tribal Adoption of Guidance •
G. Loading Lunits
1. Expression of WQBELS as Concentratipn
and Mass Loading Rates
2. Procedures to Calculate Mass Loading
Limits, - •'•;• .
3. Special Provisions Applicable to. Wet^
weather Discharges •::^'--\^_
H. WQBELS Below the Level of V..:
Quantification - ,.
1. Existing National Guidance
2. Great Lakes Guidance .
3, State and Tribal Adoption Requirements
4. Options Considered '
I. Compliance Schedules •
IX. Executive Order12291 : .'
A. Introduction and Rationale for Estimating
"Costs and Benefits for the Great Lakes Water
Quality .Guidance '.-''- •'.'.'. '••' ' '•-
B. Overview of Projected Costs Attributable •
to the Great Lakes Water Quality Guidance
1. Introduction "
2.. Methodology for Estimating Costs to Point
Sources Attributable to the Great Lakes
' Water Quality Guidance :' ., .-": ',...•
3. Deterrninatibns of Costs • , .-• ' •; .";..
4. Estimated Facility Cpnipliance Costs
.. . a: Basic Considerations "
.
, c. Monitoring Costs . . J
5. Extrapolation of Total Compliance Costs
for Sample to the Great Lakes '
Community of Point Sources ;
C. Limitations of the Analysis . ; : ,
'! l.Lunitations iii Scope ' : -
: 2. unpact of Technical Assumptions ".<
DVFindings ' ;, , ,
1. General Observations '.-' '••'," !•
2. Specific.Findings *
E. Provisions in the Proposed Guidance
Available for Use at States' Discretion to
Mitigate Compliance Costs •'--.'- ' :."'• :-.
1. Additional Time to Collect Data to Derive
a Numeric tier I .Criteria or a New Tier
: '•• -
2; Variances From Water Quality Standards
3. Mixing Zones ' _ .> •
4. Reasonable Potential to Exceed Water.
;•_ Quality -; * '.._'. ••••••••
5. Designated Use Modification '
6; Site-specific Criteria " " r
7. Total Maximum Daily Load:(TMDL)/Waste
Load Allocation (WLA) V
8.,Compliance Schedules "".-•. "
F. Sensitivity Analysis ' ,' ...•-'-.'
;'l. Tier I BCCs are Found Bioaccumulating :
2. Proposed Antidegradation Requirements
a. Step 1—Pollution Prevention
•• b. Step 2—Alternative or Enhanced
Treatment \ .
c. Step^-^Social/Economic Impact
d; Summary -
,3. Future Detection of BCCs! •_-.;:
4. Elimination of Mixing Zones for BCCs
5. Prevalence of Tier II BCCs arid Potential
- -.- BCCS '. -:; ': •- -. ,v .;•..=::
6. Evaluation of hitake Pollutant Options
7. Summary . ,.-.;'..
G. Future Analyses;' : ,] ..'-;'; ;
H, Cost-effectiveness ••': ".'.
i.'introduction. •; ' ", -
2. Pollutant Loadings,Reducti6ns .-•••'••.
3. Toxicuy-Weighted Loadings Reduction
4. Cost-effectiveness : .
5. Sensitivity Analysis •
I. Overview of Projected Benefits Attributable
to the Great'Lakes Water Quality Guidance
l..Introductipn : ; '
2. Qualitative Assessment of Benefits :
:; Associated With the Great Lakes Water
'••'•'••, Quality Guidance'..-.-... ..\, ....'.••
^a. Sensitivity and Unique Attributes of
Receiving Waters ',"';-.' ;
b. Nature of Toxic Poilutarits Addressed by
1 the GLWQG and Implications for Risk •
^Reduction • . • ; <
c. Overview of Exposed and Sensitive ,
Populations ;- ; ;
d. Conclusions . :
3. Economic Concepts Applicable to the
Quantitative Benefits Analysis :
a. The Economic Concept of Benefits ';•'.:
b. Benefit Categories Applicable to the
\GLWQG- ^--:\ ••-'. ;v-'''":" . ••'''•• "'•':•'•
4. Limitation of the Benefits Analysis
a. Causality: Linkuig the GLWQG to -
: .Beneficial Outcomes '• ". . . : -, .-.
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
b. Temporal, Spatial and Transfer Issues
L Tha Time Path to Ecosystem Recovery
From Near-term Reductions in Toxic
Loadings
li. Tha Geographic Scope of Contamination
and of Benefit-generating Activities
Throughout the Great Lakes Watershed
Ecosystem
lit. Existing Data Sources
c. Baseline and Benefits Attribution Issues
d. Contingent Valuation Method Issues
L Using CVM to Estimate Use
(Recreational) Benefits
II. Using CVM to Measure Nonuse Values
S. Cost-effectiveness of the Proposed
Guidance at Three Sites
6. Future Analysis
X Regulatory Flexibility Act
XI, Paperwork Reduction Act
Xff, Judicial Review of Provisions Not
Amended
Xlll, Supporting Documents
Appendix to the Preamble—Great Lakes
Water Quality Initiative Technical Support
Documont for Wildlife Criteria
I. Background
A, Description of Resource
I. General Statistics
Tha Great Lakes, comprising Lakes
Superior, Michigan, Huron (including
Lake St. Glair), Erie, and Ontario, are an
important part of the physical and
cultural heritage of Norm America.
From the western tip of Lake Superior
to the eastern shores of Lake Ontario,
the Great Lakes span, over 750 miles.
Termed freshwater or inland seas by
early explorers on the North American
continent, the Great Lakes provide water
for consumption, transportation, power,
recreation and a host of other uses by
aquatic life, wildlife and humans. The
Great Lakes are one of the largest surface
systems of fresh water on earth,
containing roughly 20 percent of the
world's fresh water supply and 95
percent of the freshwater of the United
States. Only the polar ice caps and Lake
Baikal in Siberia contain more fresh
water.
The Great Lakes System includes the
five Great Lakes and all streams, rivers,
lakes and other bodies of water that are
within the drainage basin of the Great
Lakos, including all connecting
channels (the Saint Mary's River, Saint
Clair River, Detroit River, Niagara River
and the Saint Lawrence River to the
Canadian Border). The Great Lakes
System spans waters in eight States—
New York, Pennsylvania, Ohio, Indiana,
Illinois, Michigan, Wisconsin and
Minnesota—and parts of the Canadian
Province of Ontario. The Great Lakes
region Is currently home to more than
40 million people, including 20 percent
of the United States population and 50
percent of the Canadian population.
Over 23 million of these people depend
upon the Great Lakes for drinking water.
The Great Lakes Basin Ecosystem—
the interacting components of air, land,
water and living organisms, including
humans, that live within the Great Lakes
drainage basin—supports hundreds of
species of aquatic life, wildlife and
plants. Over 4,500 miles of coastline, six
National Parks and Lakeshores, six
National Forests, seven National
Wildlife Refuges, and dozens of State
parks, forests, and sanctuaries are part
of this System.
Some of the world's largest
concentrations of industrial capacity are
located in the Great Lakes System. The
Soo Locks, located between the sister
cities of Sault Ste. Marie, Michigan and
Ontario, handle more tonnage of
commercial cargo than the Suez and
Panama Canals combined. Sixty-four of
the 1,000 power plants located within
the United States are situated in Great
Lakes coastal counties and generate 20
billion kilowatt hours of electricity each
year. Approximately 25 percent and
seven percent of the total agricultural
production of Canada and the United
States, respectively, occurs within the
' Great Lakes System. The Great Lakes
System also provides recreational and
economic benefits from the sport
fisheries, boating, campgrounds, and
resorts associated with it. The Great
Lakes System is a unique natural
resource affording habitat to a vast array
of living organisms, and inestimable
aesthetic beauty for the peoples of the
United States and Canada.
2. Physical Characteristics
The Great Lakes are divided into the"
Upper Lakes, Lakes Superior, Huron
and Michigan, and the Lower Lakes,
Lakes Erie and Ontario. All of the lakes
except Lake Michigan are binational,
that is, their waters are" shared by the
United States and Canada. Only Lake
Michigan is located entirely within the
United States.
In spite of their large size and
substantial volume of fresh water, the
Great Lakes are sensitive to the effects
of a wide range of pollutants that enter
the Lakes through both point and
nonpoint sources. The sources of these
pollutants include, .but are not limited
to, the agricultural runoff of soils and
farm chemicals from rural lands, city
wastes, industrial discharges, and
leachate from, disposal sites. The large
surface area of the Great Lakes also
exposes them to the direct atmospheric
deposition of pollutants from rain, snow
and dust that settle onto the lakes'
surfaces.
Lake Superior is the largest, deepest,
and coldest of the Great Lakes, and has
the longest retention time, the average
time it takes for a molecule of water to
exit the system, at 173 years. It is also
,the most pristine of the Great Lakes,
having not experienced the vast
industrial and agricultural usage of the
rest of the Great Lakes System. Lake
Michigan is the second largest lake,
with a retention time of 62 years. The
Lake Michigan basin is characterized by
sparse population in its northern
reaches and some of the most urbanized
areas in the Great Lakes System along its
southern shores. Lake Huron, with a
retention time of 21 years, is the third
largest of the lakes, and has a mixture
of industrial and agricultural areas.
Two-thirds of its watershed is still
forested.
Lakes Erie and Ontario have
significantly smaller retention times of'
2.7 and 7.5 years, respectively, as
compared to the Upper Lakes. Lake Erie
is the smallest and the shallowest of the
lakes, and is the most susceptible to the
effects of urban and agricultural
activities. The Lake Erie basin supports
an intensive agricultural base. Lake
Ontario, the eastern-most lake,
eventually receives all of the waters
from the other lakes. The Canadian
shore of Lake Ontario is heavily
urbanized, while the U.S. side is
characterized by a lower degree of
industrial activity, and moderate
farming.
Outflows from the Great Lakes are
relatively small (less than one percent
per year) in comparison to the total
volume of water the lakes contain.
Pollutants that enter the lakes through a
variety of pathways—by direct
discharge or nonpoint discharge into the
open waters of the Great Lakes, through
tributaries, or from atmospheric . :
deposition—are not readily flushed
from the Great Lakes System as hi a
riverine system. They can be made
relatively inaccessible to living , > .
organisms through volatilization,, burial
in the sediments, and degradation.
Pollutants re-enter the water column ,
through resuspension of bottom
sediments, dredging, storm events, or
volatilization cycles, where they are '
once again accessible to living
organisms. These recycling phenomena
add to the overall retention time of
chemicals within the Great Lakes
System (Andre et al., 1993; Beltran,
1992; Richardson, 1993; U.S. EPA,
1989). During the periods that chemicals
remain in the lakes, certain pollutants
tend to bioaccumulate in organisms,,
becoming concentrated at levels in the ,
organisms which greatly exceed the
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Federal^Regiiiter../"Vol..'''
[- . ., -. ... ^:.
ay. April !€, 1993 7 Proposed Rules
".'Zi?*i,iil*"- -
20807
ambient concentrations in the open ••-..-
waters of the Great Lakes. ;
3. History of Environmental Degradation
. Early settlement and related lecpnomic
activities drastically changed portions of
the Great Lakes System. The. vast tracts '.
of timber provided materials for ship
building, Construction, furniture and
specialty products. Paper making from
pulpwood developed later, with tiie
United States and Canada leading the
•world's production. Today, reforestation
throughout the Great Lakes System is a •-
critical ecosystem issue,
Commercial fishing, began in the Great
Lakes about 1820, and expanded
rapidly. The largest harvests were
recorded in 1889 and 1899 at about 147
million tons annually. Hpwe.var.Jby .the
1880s preferred species were on lie
decline, and the overall value of the
Great Lakes fishery has declined . .,.-
dramatically due the predominance of
small, relatively low value species.
Over-fishing, pollution, stream and
shoreline habitat destruction, and the
introduction of exotic species have all
contributed to the decline of the Great
Lakes fishery. i >,'"--,
Thejapid, large scale clearing of land
for agricultural purposes caused deep
changes in the Great Lakes Basin
•Ecosystem. Soils stripped of vegetation
washed away to the Lakes, clogging
tributaries, and deltas, and altering the
,flows of,waterways and changing flood
zones. Synthetic fertilizers and . "•-
chemicals to .control pests were ,
increasingly used to enhance v
production. One of the earliest
pesticides, DDT. was subsequently
identified as causiiig reproductive
failures in some species of birds. The
combined use of synthetic fertilizers,
existing sources oj nutrient-rich organic
pollutants (such as untreated human
wastes from cities), and phosphate
detergents causej widespread alga) \
blooms, resulting in eutrophication.
Industrialization followed the
agrarian settlemejat of the Great Lakes.
During this period, virtually untreated:;
wastes were intr<|lucedinto the waters
of the-System. Tie growing urbanization
that accompaniejjhe industrial
development oj the Great Lakes System
added to the overa&legradatipn of
, water quality. Nuisanbe conditions;
such as bacterial contamination, .•'.-,,
putrescence, and floating debris in
rivers and nearshof%|ffg^i were
increasingly commoTvTM^joine t
occasions, these cond%ms ca^ed fatal
epidemics of waterbornv;diseas6S Such
as typhoid. , -V
Wuh the progressive deyeio^gj^
• heavy industry, many newiheinical
substances were introduce4uito|8
Great Lakes System.- Approximately
13,000 factories that refine petroleum:
and manufacture products as plastics,
chemicals, paints, iron, steel, cars, pulp
and paper are located within the Great
Lakes basin, including 3,800 factories .
that discharge waste water directly to
the waters of the Great Lakes System. •-,'
Most of the remaining 9,000 factories
discharge wastes indirectly through
municipal wastewater treatment plants.
Metals, organic compounds and other
substances used in industrial processes
have entered the-Great Lakes System
and continue to contribute to the overall
degradation of water quality. :
4. Environmental Problems in the Great
Lakes System •'.'-.'.'' •
• - a. Nutrients. In the late 1960s, .
growing public concern about the
deterioration of water quality in the :
'Great Lakes stimulated increased
' research into the causes of . :
environmental degradation. For,. :
example, increased nutrients to the
lakes had dramaticaily stimulated the
growth of green plants and algae.
Decomposition of these organic .-
materials resulted in decreased levels/of
dissolved oxygen.in bottom waters.-This
process, called eutrophication, had
become increasingly common in
shallow bays throughout the Lakes, and
Lake Erie in particular. As oxygen levels
continued to drop, certain species of
insects and fish, such, as mayflies, trout
and walleyed pike were essentially
displaced frpnraffected areas of the
Great Lakes Basin Ecosystem^ Pollution •
tolerant species, requiring less oxygen,
such as sludge worms and carp,
replaced the original species. Lake-wide
changes in the type of bottom-dwelling
organisms and nsh,*as well as in species
of algae, were good indicators of overall.
oxygen depletion in the lakes.
Environmental managers determined
that a lakewide approach was necessary
to adequately control the problems
caused by accelerated eutrophication.
By the late 1960s, United States and
Canadian regulatory agencies were in
agreement that limiting the loadings of
phosphorus was the key to controlling
excessive algal growth aridi therefore,
chronic eutrophication. An effluent
limit of one ug/L of phosphorus was
imposed on all major (greater then 1 .
million gallons per day) municipal
sewage treatment facilities in the Great
Lakes basin. Some States took . .
additional steps, such as limiting the
phosphorus content in household
detergents, to cut phosphorus
discharges to the Great Lakes. In the late
1970s, the United States and Canadian
Governments undertook the
"development of phosphorus budgets for
each lake considering point source
loadings and nonpoint source runoff
loadings. " " •:'.•""-•'-'-
• As aresiilt of all of these efforts, open.
lake phosphorus concentrations-have'•
declined. To date, phosphorus loadings
from municipal sewage treatment
facilities have been reduced by an
estimated,80 to 90 percent. These
reductions have resulted in dramatic
improvements in nearshore water
quality and measurable improvements
in open lake conditions. For Lakes '
Huron, Michigan and Superior,
phosphorus concentrations have
historically been near or below
established targets. In Lakes Erie and.
Ontario, phosphorus concentrations
were more than twice'the target values
in the early 1970s, but have been
reduced to levels at or below the targets
since thelate 1980s. At this time, the
United States is meeting Its;phosphorus
load commitments for each lake. Over
the long term, oxygen depletion rates
have :declined, with the rates of • v
depletion for recent years among the
lowest reported. : '
; EPA and the Great Lakes States *
recognize that existing efforts to ,
maintain or further reduce phosphorus
loadings must continue. The proposed
Great Lakes Water Quality CJuidahce • ,,
does not expressly address phosphorus
loadings to the Great Lakes, however,
because separate ongoing programs have
been established to address this issue.
b. Toxic Substance?. Toxic ' ,
contamination of the Great Lakes .
System has significantly impacted the
environment both in and around the ..
lakes, and the health Of the aquatic life,
/wildlife and humans that depend upon
the lakes for food and drinking water.
Toxic pollutants,'including metals and:
man-made organic chemicals, can be
acutely poisonous in relatively small
amounts and can be injurious, through .
chronic exposure, in minute - :
concentrations. Many contaminants
present in the Great Lakes System have
the potential to increase the risk of •;
cancer, birth defects, genetic mutations
and reproductive impacts through long-
term exposure. Adverse impacts on fish,
bird, aiid mammal populations in the
Great Lakes associated with the effects
of toxic chemicals include: Cancer,
death, eggshell thinning, population
declines, reduced hatching success,
abnormal behavior (such as : .
abandonment of nests), infertility, birth
defects (such as crossed beaks and club :
feet) and ilhiesses such as chick edema.:
They also include less visible effects on,
body chemistry, including abnormalities
in the thyroid, liver and endocrine;
systems.. • ! , • • . --,...
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
Onca introduced into the Great
Lakes—whether by point sources,
atmospheric deposition, contaminated
sediments, ground water, or surface
runoff—some toxic substances have
physical, chemical, or biological
properties that make the chemicals
persist for extended periods in the
aquatic environment without degrading
or otherwise disappearing, and
bioaccumulate through the food chain of
tho Groat Lakes System. While the
concentrations of these chemicals in
water may be so low as to be
undatectable by available analytical
techniques, persistence and
bloaccumulation can increase the levels
of these contaminants to toxic
concentrations. These persistent
biotccumulative toxic chemicals are of
particular importance to the Great Lakes
Basin Ecosystem due to the long
retention times of the individual lakes
and the cycling of toxics from one
component of the ecosystem to another.
Several characteristics of the Great
Lakes result in their being particularly
susceptible to relatively nondegradable.
lipophilic chemicals. These
characteristics include: (1) Long
hydraulic retention times (relatively
cfosod systems); (2) low biological
productivity; (3) low suspended solids
concentrations; (4) great depth; and C5)
tho presence of self-contained fish and
wildlife populations dependent on the
Groat Lakes System for their water and
food supply. Taken together, these
characteristics result in such pollutants
remaining in the system for long periods
of time and bioaccumulating in fish and
Wildlife at concentrations which are
orders of magnitude above ambient
concentrations in the water column.
Physical transport is one pathway by
which pollutants are removed from the
Great Lakes Basin Ecosystem. Because
of ths long hydraulic retention times of
tho Great Lakes, however, downstream
transport of pollutants is not a
significant pathway of removal, and as
discussed below, long retention times
are but one of several attributes which
result in recycling and prolonged
recovery rates for the Great Lakes. The
hydraulic residence times for the Great
Lakes, based on present diversion rates,
range from 2.7 years for Lake Erie to 173
years for Lake Superior.
Tho main processes which account for
loss of a pollutant from the active
compartments of the lakes are burial,
degradation, volatilization and
ndvecUon (or diffusion) out of the
watershed. Of these processes, the
settling and subsequent burial of many
persistent particulato-associatod
pollutants is believed to be a greater .
factor in the removal of the pollutants
from the water column in the deeper
Great Lakes than is advection,
degradation and volatilization.
However, recent evidence from Lake
Superior also strongly implicates
volatilization as a major pathway for the
removal from the water column of some
PCB congeners (Eisenreich, 1992).
Hydrophobia pollutants preferentially
sorb to biotic and abiotic particles in the
water column. Both types of particles
will sink and transport pollutants to the
bottom sediments. Because of their low
biological productivity, however, the
Great Lakes are very efficient at cycling
nutrients and carbon^ Therefore much, if
not most, of the pollutant mass
associated with biotic particles is either
consumed by higher trophic levels and
bioaccumulated up the food chain, or is
released back to the water column as
these particles are degraded by bacterial
action. Pollutants sorbed to abiotic
particles may reach the bottom
sediments, but this is a slow process
ranging from months to years due to the
low suspended particulate
concentrations and net sedimentation
rates. Particles which do reach the
bottom sediments are subject to
lesuspension resulting from storm
events and other disturbances.
The affinity of many organic
pollutants for binding onto suspended
particles is well established. Partition
coefficients (K
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Federal Register-'./ Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules \ 20809
example, data from mass balance
studies and inventories in the Great
Lakes System indicate that there is a .
significant reservoir of PCBs in the soils
and sediments that will continue to
release PCBs into the environment at ,
significant rates for decades (Aiidre et
al., 1993; Beltran, 1992; Richardson,
1993; U.S. EPA, 1989). While , ',
concentrations of persistent,
bioaccumulative pollutants may
eventually decline, for the Gre,at Lakes,
the rate of decline will occur much
slower than in systems with lower
hydraulic retention times or more
productive systems with greater
sedimentation loading rates. Once
released to the Great Lakes Basin
Ecosystem, toxic substances that are
slowly degrading and bioaccumulative
will cycle within the system for
decades, exerting biological effects and
presenting relatively high levels of risk
to aquatic life, wildlife and humans
which inhabit the basin. An example of
a pollutant class that is highly persistent
and bioaccumulative is polychlorinated
biphenyls (PCBs), which have estimated
half lives for biological degradation of
months up to several yearsj:and which.
.bioaccumulate in, the food chain to
levels 1,800,000 times the concentration
in the water column (Eisenreich et al.,
1989; Ballschmitter et al., 1989).
Continued or new inputs of such
pollutants serve to exacerbate
impairments of beneficial uses.
The rapid decline of PCB :
concentrations in lake trout from Lake
Michigan during the latter half of the
1970s reflects the relatively rapid
response of the water column to . •.'
decreases in loadings. Hydraulic
transport of the pollutant from Lake
Michigan, with a hydraulic residence
time of 62 years, into Lake Hurbn has ,
-little effect on PCB,concentrations in the
water and fish. Rather, internal -
responses and processes that operate in
the Great Lakes because of their depth
and long hydraulic residence times
control the pollutant concentrations in
response to loadings. •
• PCB concentrations in Lake Michigan
lake trout declined from a maximum of
22.9 mg/kgin 1974 to 5.6 mg/kg in 1982
(DeVault, et al., 1986; DeVault, 1993a};
(Figure 1-1). The pattern of decline
through 1982 is consistent with.first.:
order kinetics calculations (DeVault et
al., 1986). Beyond 1982, however, the
observed PCB concentrations in fish
tissue collected in 1984,1988, and 1990
"are significantly higher than levels
predicted by first order rate constants
calculated from the 1974-1982 period
(DeVault, 1993a). Thus, while PCB
concentrations are still declining ••'"•
through 1990, the rate of decline is '.
slowing and may be leveling off,
resulting in concentrations continuing •
well above water quality criteria. "
Studies on biodegradation indicate that
the most highly chlorinated (least toxic)
forms'of PGBs-are degraded first, leaving
the most toxic forms behind; Laboratory
experiments designed to provide
optimal conditions for microbial activity
have not been able to achieve complete
PCB dechlorination, suggesting that the
remaining forms of PCB may persist ,
indefinitely (Adler et al., 1993).
BILLING CODE 6560-5W>
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20810 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
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Federal Register / Vol. 58, NO. 72 7 Friday, April 16, 1993 /Proposed Rules
20811
The slowing in the rate of decline of
PGBs in fish tissue is also supported by
coho salmon data (DeVault et al., 1988;
DeVault, 1993b) (Figure 1-2). Because
coho are stocked; and are in the lake for
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concentrations than lake trout, which
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(FigureI-3). .
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concentrations in Lake Michigan lake
trout are shown in Figure 1-4, Data on
concentrations of DDT in coho salmon
across all the lakes are shown in Figure
1-5 (DeVault et al., 1986; DeVault et al.,
1988; DeVault, 1993a; DeVault, 1993b).
The DDT levels in coho salmon are
below levels corresponding to 10^5 ."'..-
mortality risk in all lakes except Lake
Ontario. For lake trout, the DDT level in
1990 was substantially above the level •
corresponding to the 10-5 risk level.
BILUNG CODE 6580-SO-P
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20812
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20816
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
Thoso substances appear to ba
approaching equilibrium in the Great
Laics System at unacceptably high
levels due to continuing loadings from
a variety of sources, such as: (1)
Historically contaminated sediments in
the embayments as well as the open
lakes; (2) tributary inputs resulting from
point sources, spills and direct runoff
from urban and rural areas, and/or
resuspension from contaminated
sediments; and (3) atmospheric
deposition of pollutants. Concentrations
measured in 1990 for PCBs and
chlorinated pesticides exceed the fish
tissue concentrations that correspond to
current EPA 304(a) water quality criteria
by several orders of magnitude (Table I'-
ll (DeVault 1993a). If a new equilibrium
is being reached given current mass
loadings, then substantial further
reductions in mass loadings to the lakes
will be necessary to eliminate fish
advisories.
TABLE M.—COMPARISON OF RECENT MEASURED FISH TISSUE CONCENTRATIONS IN LAKE MICHIGAN LAKE TROUT AGAINST
CALCULATED FISH TISSUE CONCENTRATIONS CORRESPONDING TO CURRENT EPA SECTION 304(A) AMBIENT WATER
CRITERIA AT 10-J RISK LEVEL. '
Substance
PCBs
• : ,,'"'*' "" V . ' ; ' '"
DOT/DDE ............1.
Cblcxdant .. « .!.........„. .„......„„
Djekjrfn .. „ ..........
1990 measured fish tis-
sue concentration (mg/
kg) (mean and 95% con-
fidence interval)
' 2.72
(2.45-2.99)
1,39
(1.20-1.58)
0.44
. (0.36-0.52)
0.198
(0.16-0.20)
Calculated fish tissue
concentration (mg/kg)
corresponding to 304(a)
criteria
0.014
0.316
0.083
0.0067
Source: DoVauit, et a)., 1906; DeVault, 1993a.
Within the Great Lakes basin, an
ecosystem approach to environmental
management has been adopted by U.S.
and Canadian agencies whereby
physical, chemical and biological
aspects of the aquatic system are
considered concurrently, rather than in
isolation. This approach is dictated
largely due to the closed nature of the
Great Lakes Basin Ecosystem. As noted
above, persistent bioaccumulative
pollutants tend to remain within the
system for long time periods, recycling
among various compartments (e.g.,
water, sediment, biota). As a result, the
residence time of the pollutants may be
several times longer than life spans of
oven relatively long-lived species, such
as lake trout and fish-eating birds. This
is in contrast to other aquatic systems
(e.g., small lakes, rivers, or marine
coastal areas) where once the pollutant
load to the system is stopped the
pollutants are generally removed from
the system relatively quickly through
such mechanisms as hydraulic transport
out of the watershed, dilution through
tidal effects, or burial because of high
productivity and high sedimentation
rates. Thus, in such other aquatic
systems pollutants are not present in the
ecosystem long enough to affect
successive generations of the biota (i.e.,
the pollutant is removed within one life-
cyclo of the top predators). Three
examples illustrate the uniqueness of
the Great Lakes Basin Ecosystem in this
regard: Lake trout, colonial birds, and
bold eagles.
In the Great Lakes, the lake trout is
the classic example of a key species,
fundamentally important to the
naturally-evolved aquatic community.
Lake trout are very long lived (some live
longer than 25 years), and while their
•populations have been devastated by
overharvesting and the introduction of
the sea lamprey, these fish are also
being subjected to a variety of
impairments from toxic pollutants.
Past evidence indicates ambient levels
of PCBs hi the Great Lakes could impair
reproduction in lake trout. When nine
groups of lake trout fry were exposed for
six months to concentrations of PCB
and/or DDE similar to that hi water and
zooplankton in Lake Michigan in 1975,
mortalities in the nine exposed groups
were 40.5 percent to 114 percent greater
than hi the control group. These data
suggest that if lake trout had spawned
successfully hi Lake Michigan in the
mid-1970's, nearly twice as many of the
fry would have died within the first 6
months than if no pollutants were
present. However, more recent efforts to
estimate the extent to which fish yields
(i.e., harvestable catches) are being
compromised by present levels of
pollutants in the Great Lakes System are
inconclusive. Most biological
consequences of fish exposure to
pollutants have been measured at the
physiological or organism level rather
than the population level, so it is
difficult to determine the extent to
which current pollutant concentrations
hi the Great Lakes may be inhibiting the
ability of this species to re-establish .
viable, self-sustaining populations. ;
Several fish-eating bird species are at
greater risk from exposure to pollutants
in the Great Lakes than in other aquatic
systems because their foraging range is
entirely within the Great Lakes basin for
all or part of each year. Species of fish-,
eating birds known to be affected by
pollutants in the Great Lakes include
the double-crested cormorant, black-
crowned night heron, osprey, herring
gull, common tern, Forster's tern, and
bald eagle. Colonial waterbirds of the
Great Lakes have been shown to
bioconcentrate pollutants from their
food (i.e., fish) 20 to 30 fold.
The Forster's tem, designated as
threatened or endangered, is sensitive to
PCBs, chlorinated dioxhis and furans,
and is limited to marshy embayments
such as Green Bay, Saginaw Bay and
Lake St. Clair (all of which are
experiencing problems with
bioaccumulative organic pollutants), hi
a comparative study of Forster's terns
colonies on Green Bay (Lake Michigan)
and Lake Poygan (a relatively
uncohtaminated lake approximately 50
miles from Green Bay, but still in the
Green Bay watershed), the Green Bay
colonies were severely stressed by toxic
pollutants. The median equivalents of
TCDD (2,3,7,8-tetrachlorodibenzo-p- .
dioxin) were almost 11 times greater in
tern eggs from Green Bay than Lake
Poygan (2175 versus 201 pg/g); the -
hatching success of sibling eggs was 75
percent lower at the Green Bay colonies;
hatchlings from laboratory incubations
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Federal Register'-/'.Vol. 58, No. 72 / ffriday, April liB, 199377 Broposed Rules 20817
of .Green Bay eggs weighed
approximately 20 percent less than :
those from Lake jPoygan; and the ratio of
Uver weight to total weight was 26
percent greater. Also, nest abandonment
and egg disappearance were substantial
at .Green Bay, but not at Lake Poygan.
The bald eagle is one of the most
highly visible symbols of the effect of
toxic pollutants in the'Great Lakes
basin. The total number of active nests •
along the Great Lakes shoreline in ' :
Wisconsin and Michigan in 1970 was
' only five, compared to an estimated .
density of one pair per every 8 to 18 km
of shoreline before European settlement
Between 1961jand 1970, shoreline nests
in these states were successful only 10
percent of the time, with an average
reproduction of only 0.14 fledgling per
nest, compared to stable, inland
populations with 50 percent success
rates and an average of 0.7 young per
nest. Declines of bald eagle populations
in the Great Lakes states were associated
with a thinning of egg shells of at least
12 percent. Furthermore, significantly
greater concentrations of PCBs.DDE,
and dieldrin were found in eagle eggs
along the Great Lakes shoreline between
1969 and 1986 than in eggs from inland
nests (Table 1-2).
TABLE 1-2.-—CONTAMINANT GoNCENTRAtipN (PPM) IN BALD EAGLE EGGS FROM GREAT LAKES SHORELINE NESTS AND
,; ' . . FROM INLAND SITES , , •-'.-. . .
: Nest site ,
L Superior ................ - ......;..-.............
Wisconsin .............. ..,......,......~........... ................
Inland ...................-.....-....-.........—.... ...............
L Erie ................ i.™...... .. „„..„....„„
Michigan ......i..».........,~ ....... ..
Inland ......... ......................................
Years
'69-'82
'86
• '68— "85
• 'SB
'76-'85
.\ '• '86
'BS-'fld
'86
PCS
e o_on 7
12.9-14
« Q*}A R
IP A—11 fV
•ic n_eo.A.
8.6-44.0
It*— A A f\
2.0^29.0
DDE
it./— oy.o
2.4-S.5
.1—53
U.*m- 2.7
-,. O.B— 2O.5
25-10.0
, l^J-rl4iO
i.i-mo
Dieldrin
0.42-1.1
0.18-0.51
0.20-0.79
0.06-0.09
0.53-1.7
0.25-0.69
0.14-1.6
• •'• " 0.08-0.9
Recent surveys have shown a general
improvement in inland populations of
bald eagles in Michigan, Wisconsin and
Minnesota, and some eagles have re- '•
established nests along the Lake
Superior shore and sporadically
produce fledged young. In recent years,
eagle populations have expanded along
the Canadian Lake Erie shoreline, with
some breeding success^reflecting the \ •
reduced concentrations of _•
organochlorine pesticides in Lake Erie
fish and waterfowl. No nesting attempts
• have been recorded along the lake
Ontario shoreline, however. Nesting
rates in the Great Lakes basin iag still
lagging well behind inland populations.
This is indicative of the continuing
elevated concentrations of persistent ':
bioagcumulative pollutants in the fish
and wildlife on which bald eagles feed
in the Great Lakes basin. -^
The Great Lakes States have issued
709 fish consumption advisories that are
currently in effect for waters within
their boundaries, including waters of '
the Great Lakes, Great Lakes tributaries,
and waters outside the Gigai Lakes
drainage basin. Pollutants.foivrhich.
•these fish advisories exist incln|e 8 of
the 28 bioaccumulative chemicals of
concern identified in the proposed
Guidance. If a potential local hiealth
threat exists due to the consumption of
sport-caught fish, a State pCchoose to
issue warnuigs or provide guidance on
the quantity and type of contaminated %
fish which may be consumed. The Great
Lakes States in-general issjje&'i
contaminant advisories whicliHre.based
. on a system incorporating and 'weighing
• such factors as the type of contaminants
found in Great Lakes fish flesh,
contaminant levels:to fish of vfflious
sizes and species, the Apical
consumption rates of sport-fishers, an
evaluation of the human health risks
due to potential impacts. Fish advisories
in the Great Lakes system are discussed
further ini section ILG.ll below,
; B. Great Lakes Water Quality Agreement
1. History of the Great Lakes Water
Quality Agreement ,
The concept of an ecosystem ,,
^approach to the management of the ' :
Great Lakes evolved from the better
understanding of how environmental
damage has resulted from human use of
.the natural resources of the Great Lakes
System. The research, monitoring and
regulatory prbgrams of the United States
and Canada illustrate the connections
between the use of land, air and water
resources and the need to consider the
impact of pollutants on the entire Great
Lakes Basin Ecosystem. Because of
mutual concerns about the protection
and use of shared waters, the
governments of the United States and
Canada have created institutions to •
foster the joint environmental .'"; ''
management of the. Great Lakes. .
a. The Boundary Waters Treaty of
1909, In. 1905, the International'
Waterways Commission was created to -
advise the governments of the United
States and Canada on water levels and
flows ia the Great Lakes, especially in
relation to the generation of electricity
by hydropower. However, the
Commission's limited advisory powers.
.proved inadequate for problems related
to pollution and.environmental
management. The Boundary Waters
Treaty, signed in 1909, provided for the
creation of the International joint
Commission (IJCj, \vith the authority to
resolve disputes over the use bf water
resources fliat crossed the international
boundary of the two countries. Since '
then, inost of the IjC's,actions have been
devoted to regulating[Water flows, •
earrying out studies requested by the ,
United States and Canadian
. governments; and advising the • •
, governments regarding pollution-related
/problems. : -;
Water pollution was one of the first
problems referred to the IJC for study in
1912. The IJC concluded in 1919 that
water quality problems in the Great •
Lakes System were of a serious nature
and required further pollution control
on the part bf both countries to resolve, :
While no new treaty agreement was
signed, the United States and Canada
each subsequently established water
pollution control programs covering a -
range of activities. Additional studies in
the 1940s led the IJG to advocate *
establishing narrative water quality •->
objectives for the Great Lakes and the
creation of technical advisory boards to
monitor Great Lakes water quality.
During the 1950s and 1960s, problems
on the Great Lakes reached a: critical- '
juncture. In 1964^ the IJC began a new
reference study oa pollution iii the
Lower Lakes. The 1970 reference study
report identified excessive phosphorus
loadings as the principal cause of
.eutrophicatioaand proposed system-
wide efforts to reduce phosphorus • , --;
loadings from all sources. The ^C also
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20818
Federal Register / Vol. 58. No. 72 / Friday, April 16, 1993 / Proposed Rules
urged the United States and Canadian
governments to establish uniform
effluent limits for all industries and
municipal treatment systems in the
Groat Lakes System. The conclusions of
the reference study prompted the
United States and Canada to negotiate a
now, comprehensive agreement on the
environmental management of the Great
Lakes in the 1972 Great Lakes Water
Quality Agreement.
b. The 1972 Great Lakes Water
Quality Agreement. The Great Lakes
Water Quality Agreement, signed by the
United States and Canadian
Governments in 1972, established
common water quality objectives for the
Great Lakes System. Despite complex
jurisdictional problems, the basic
premico of tho 1972 Agreement was that
binational management of the Great
Lakes by tho United States and Canada
could effectively protect the Lakes from
further adverso effects of pollution. The
1972 Agreement addressed overall
pollution and water deterioration in the
fiva lakes, with an emphasis on
controlling excessive nutrient loadings.
Each country agreed to implement
pollution control actions within its own
statutory framework in order to fulfill"
tho requirements of the binational
agreement. Tha chief objective was the
reduction of phosphorus levels to no
more than 1 ppm in discharges from
larga municipal sewage treatment plants
into Lakes Erie and Ontario. New limits
were also placed on industrial
discharges. Other objectives of this
process included the elimination of oil,
visible solid wastes and other nuisance
conditions. Both countries established
Great Lakes research programs, along
with programs for cooperative and
separate efforts. The 1972 Agreement
also contained commitments for joint
international surveillance and
monitoring programs, coordinated
through the regional office of the IJC.
Thesa programs focused on freshwater
chemistry and reporting the
concentrations of ambient pollutants.
In 1977, tho Parties assessed the
progress in meeting the binational
objectives, and determined that total
discharge of nutrients into the Lakes
had been noticeably reduced. Man-made
outrophication, bacterial contamination
and the more obvious nuisance
conditions in rivers and nearshore •
waters had declined. However, new
environmental problems involving toxic
chemicals were identified through the
Great Lakes research programs and the
joint United States and Canadian
surveillance and monitoring programs.
Additionally, an Upper Lakes study
concluded that phosphorus objectives
should be set for Lakes Huron, Michigan
and Superior.
c. The 1978 Great Lakes Water
Quality Agreement. In 1978, the United
States and Canada signed revisions to
the Great Lakes Water Quality
Agreement that preserved the basic
features of the preceding 1972
Agreement while building on its
achievements. Like its predecessor, the
1978 Agreement called for establishing
common water quality objectives,
improving pollution control throughout
the System, and continued monitoring
by the IJC. The Agreement shifted the
focus from solely the control of
nutrients to include the control of toxic
substances, calling for the virtual
elimination of the discharge ,of
persistent toxic chemicals. Persistent
toxic chemicals which bioaccumulate
can be particularly hazardous to aquatic
life, wildlife, and humans. To further
improve pollution control, the 1978
Agreement also set target loadings for
phosphorus in each Lake.
In recognition of the need to develop
an integrated ecological approach, and
in contrast to the previous Agreement
which called for the protection of the
waters of the Great Lakes, the Parties to
the 1978 Agreement expanded the area
of focus to the Great Lakes Basin
Ecosystem, calling for the restoration
and maintenance of the chemical,
physical and biological integrity of the
waters of the Great Lakes Basin
Ecosystem. The Great Lakes Basin
Ecosystem is defined as the interacting
components of air, land, water and
living organisms, including humans,
within the drainage basin of the St.
Lawrence River at or upstream from the
point at which this river becomes the
international boundary between Canada
and the United States (Article I).
d. The 1987 Amendments to the Great
Lakes Wafer Quality Agreement. Article
X of the 1978 Great Lakes Water Quality
Agreement (GLWQA) required the
United States and Canada to conduct a
comprehensive review of the Agreement
following each third biennial report of
the IJC. Following independent reviews
in 1987, the United States and Canada
mutually agreed to initiate joint •
negotiations to revise the GLWQA. The
negotiations centered on the
advancements made in science and
technology since 1978, and the need to
clarify the roles of the two governments
and the IJC. The primary terms of the,
current GLWQA are discussed in
section B.2, below.
2. Major Provisions of the Great Lakes
Water Quality Agreement
The goal of the current Great Lakes
Water Quality Agreement is to restore
and maintain the chemical, physical
and biological integrity of the waters of
the Great Lakes Basin Ecosystem. To
achieve this purpose, the United States
and Canada, as Parties to the
Agreement, committed to using
maximum efforts to develop programs,
practices and technologies necessary to
gain a better understanding of the Great
Lakes Basin Ecosystem, and to eliminate
or reduce to the maximum extent
practicable the discharge of pollutants
into the Great Lakes System. Consistent
with the provisions of the GLWQA, it is
the stated policy of the Parties that:
a. The discharge of toxic substances in
toxic amounts be prohibited;
b. The discharge of persistent toxic
substances be virtually eliminated; and
. c. Coordinated planning processes
and management practices be developed
and implemented by each jurisdiction to
ensure adequate control of all sources of
pollutants.
The GLWQA contains both narrative
and numerical objectives for the
protection of the waters of the Great
Lakes System. The General Objectives in
Article ffl are narrative statements
consistent with those in effect in all
States, which'provide that the waters of
the Great Lakes System should be free -
from substances that, for example, -
interfere with beneficial uses, or
produce conditions that are toxic or
harmful to human, animal or aquatic
life.
Article IV, Annex r contains narrative
and numerical pollutant specific
objectives that represent the minimum
levels of water quality desired in the
waters of the Great Lakes System. They
are not intended to preclude the
establishment of more stringent
requirements on the part of either the
Parties to the Agreement, or the States
or Provinces, and are regarded as
interim objectives which the Parties
intend will be revised and
supplemented over time, hi areas where
the General or Specific Objectives of the
Agreement are not being met due to
human activity, the United States and
Canada agreed to identify and work
toward the elimination of Areas of
Concern, Critical Pollutants, and Point
Source Impact Zones pursuant to Annex
2.
Article V sets forth provisions for
water quality standards, other regulatory
requirements and research. Water
quality standards and other regulatory
requirements of the two governments • .
are to be consistent with the
achievement of the General and Specific
Objectives. The United States and
Canada also agreed to use their best
efforts to ensure that water quality
standards and other regulatory - ".•
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Federal Register / Vol. 58,>No. 72 / Friday, AprillS, 1993 7 Proposed Rules
20819
requirements.of the State and Provincial
Governments are .similarly consistent
•'withthe achievement of these
Objectives arid to establish research
priorities for the Great Lakes In -,.
accordance with'Annex 17.
Article VI .provides that the tJirited
States and Canada, in cooperation with
State and Provincial Governments, will
continue to develop and implement
programs and other measures to fulfill
the purpose and objectives of the
Agreement Seventeen problem areas are
specifically identified, including
pollution from municipal and 'industrial
sources, eutrophication. shipping and
dredging activities, .airborne toxics and
remediation activities. •'"
Article Vn outlines the powers,
responsibilities, and functions of the
IJC. Article VIII provides for the -;
establishment of the Great Lakes Water
Quality Board and Science Advisory
Board to help the IJC perform its
functions.under.the Agreement Articles
IX through XV outline further roles and "
responsibilities for the IJC, United States
and Canadian Governments, and State *
and Provincial Governments.
Seventeen Annexes to the Agreement
contain additional provisions adopted'
by the United States and Canada. Annex
1 provides specific numerical and
narrative objectives for identified
chemical, physicaly microbiological and
radiological conditions. These
Objectives to protect the recognized
most sensitive use in all waters of the
. Great Lake& were based on information.
available at the time of adoption on
cause-effect relationships between
. pollutants and receptors. Additional,
specific ecosystem objectives and
indicators were adopted for Lake
Superior, Ecosystem objectives and-
indicators will also be developed in the
future for Lakes Erie, Huron, Michigan •
and Ontario. Annex 2 provides for the
development and implementation of
Remedial Action Plans (RAPsj sand '
Lakewide Management Plans (LaMPs) to
address pollution problems associated
with 14 identified use impairments in
nearshore and open lake .waters. The
development of RAPs and LaMPs
pursuant to this Annex is discussed
further in sections I.G.3. and I.G.4. of
the preamble below. The provisions of
Annex. 3 seek to minimize
eutrophication problems and.prevent
; degradation with regard to phosphorus
in the boundary waters of |he Great
Lakes System by setting phospaorus
load reduction targets. The achievement
• of these load reduction targets was
discussed in section I.A.4.a. :ab'6ye. The
remaining Annexes address a wide
range of issues including discharges of
pollutants from vessels; pollution from
shipping sources; dredging; discharges
frorn onshore and offshore facilities;
joint contingency planning; hazardous
polluting substances; surveillance and
; monitoring; persistent toxic substances;
pollution from non-point sources;
contaminated sediment; airborne .toxic
substances; pollution frorn
contaminated groundwater; and
research and development activities,
The United States and Canada, meet .
twice each year to discuss the state of
the Lakes and report to the public
regularly on the progress of their Great
Lakes cleanup efforts. Pursuant to the
Agreement, the governments complete
technical and progress reports by
specified schedules and submit them to
the IJC for evaluation and comment.
3. Implementation of the Great Lakes
Water Quality Agreement
a. The International Joint ; .
Commission. The International Joint
Commission (IJC) was established by the
Boundary Waters Treaty of 1909; and is
composed of six Commissioners, three
each appointed by the Prime Minister of
Canada and the President of the United "
States. The IJC. does irot function as a
separate national delegation, but as a
single body seeking common solutions '.
to me joint interests of the two
countries. All Commissioners are
expected to act independently of their
respective national concerns.
The IJC has three primary ;
responsibilities for lie Great Lakes
outlined under the original 1909 Treaty:
The limited authority to approve
applications for the use, obstruction or
diversion of boundary waters on either
side of the border that would affect the
natural level or flow of either side; to
conduct studies of specific problems
under request from title United States;
and Canadian Governments; and to
arbitrate specific disputes which may,
arise between the two governments in
relation to boundary waters. Upon
approval of both Parties, any matters of
difference may be referred to the IJC for
a final decision. : • • .
In addition to these specific powers,
proscribed to the IJC under the 1909,
Treaty, the IJC monitors progress in
achieving the goals of the Great Lakes .
Water Quality Agreement. Two standing
advisory boards, the Water Quality
Board and the Science Advisory Board,
assist in collecting, analyzing and '
distributing data, and coordinating the
implementation of approved actions :
between the cooperating governmental
agencies. ,
The Water Quality Board is the
principal advisor to the IJC and consists
mainly of senior staff from the Federal,
State and Provincial control; agencies ;
selected equally from both countries.
The Water Quality Board is responsible
for promoting the coordination of Grea*
Lakes programs among the different
levels ofgovernmentand' ad vising the
Commissioners on major issues. The "
Science Advisory Board consists '
primarily of government and academic .
experts who advise theWater Quality
Board and the IJC on scientific findings
andxesearch needs. Both have special
committees, task forces and work'groups
to address specificissues.
b. Provisions for Consultation and
Review. Under Article IV and Annex I,
the Parties committed to the
development pi" Specific Objectives
designed to protect the most sensitive
use in the Great Lakes waters. These
standards, referred to as,"Specific
Objectives" under the Agreement, were
intended by the United States and
Canada to represent "the'minimum
levels of water quality desired to the
boundary waters of the Great Lakes
System." A number of Specific
: Objectives have been developed jointly
by the United States and Canada,
including narrative and numeric criteria
for persistent toxic substances, non-
persistent toxic substances, and other
conventional pollutants. The ; •
Agreement, however, recognizes that
, consistent with the policy of virtual
elimination of persistent toxic
pollutants set forth in the Agreement,
these Specific Objectives should :be
'. recognized only as "interim measures."
The Agreement requires the Parties,
along with State and Provincial
' governments, to consult and, as
necessary, establish additional Specific
Objectives under Annex 1 or modify
existing ones. Article X of the GLWQA
provides for the modification of existing
Objectives and the adoption of new
Objectives, the modification or
improvement of programs and joint
measures, and the amendment of the
Agreement or aiiy of its Annexes*
Article X also requires the Parties: to
conduct a comprehensive review of the
• operation and effectiveness of the
• Agreement and to evaluate progress in
achievingits goals.
c. Status of Negotiations With Canada
on Revising the Specific Objectives. The
United States/Canada Binational
Operations Committee (BOG) is
currently responsible for developing ;
modifications to the Objectives in /
Annex 1. The United States.and Canada,
-through the BOG, have agreed to pursue
common water quality criteria,
methodologies and implementation •" [
procedures for the waters of the Great
Lakes System! EPA intends to submit
the numeric criteria, methodologies, and -.
implementation procedures contained
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20820 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
in the proposed Guidance as the basis
for the United States' proposal to
modify the GLWQA pursuant to' Article
X.
C. Governors' Toxics Agreement
In 1986, the Governors of the eight
Great Lakes States signed the Great
Lakes Toxic Substances Control
Agreement (Governors' Agreement),
pledging the States' cooperation in
studying, managing and monitoring the
Groat Lakes as an integrated ecosystem.
The purpose of the Agreement is to
establish a framework for coordinated
regional action in controlling toxic
substances entering the Great Lakes
System; to further the understanding
and control of toxic contaminants; and
to develop common goals, management
practices and control strategies for
toxics to ensure a cleaner and healthier
Great Lakes Basin Ecosystem.
The Governors' Agreement identified
six principles to guide State actions to
address pollution in the Great Lakes.
First, the Governors agreed to manage
tho water resources of the Great Lakes
based on a recognition of the economic
and environmental importance of this
natural resource. Second, the Governors
committed to managing the Great Lakes
as an integrated ecosystem, recognizing
that the water resources of the
ecosystem transcend political
boundaries. Third, the signatory States
concurred that the problem of persistent
toxic substances constitutes the
foremost environmental issue
confronting the Great Lakes. Fourth, the
Governors committed to continue
reducing toxics hi the Great Lakes
System to the maximum extent possible
consistent with, the Federal Clean Water
Act goal of prohibiting the discharge of
toxic pollutants in toxic amounts as
well as the Great Lakes Water Quality
Agreement's goal of virtual elimination
of tho discharge of all persistent toxic
ffubstances. Fifth, the States committed
to cooperating among themselves and
with local and State agencies, regional
groups, tho Federal government, the IJC
and tha public in the study, monitoring
and management of the Great Lakes.
Finally, the States agreed to work
cooperatively to improve the region's
Information retrieval and technical
analysis capabilities, recognizing that
compatible data bases are key to the
development of effective regulations
and tho control of toxic substances in
the Great Lakes System.
The States also agreed that
maintaining the water quality of the
Great Lakes and stimulating economic
growth are complementary goals. By
maintaining and improving the quality
of Groat Lakes waters, the States
indicated that they would sustain water
supply systems and commercial,
manufacturing and recreation
industries, while creating new economic
development opportunities. Therefore,
the signatory States agreed to maintain
a high standard of water quality, when
establishing regulatory standards, and to
allow new or increased discharges that
have the potential to lower water quality
only when no prudent or feasible
alternative to such discharge exists.
The signatory parties also agreed that
the permitting process is the best means
now available to regulatory agencies and
dischargers to control the releases of
toxic substances into the Great Lakes
System and that discharges, emissions
Or releases of toxic substances will be
controlled by a regulatory permit
process in order to reduce or eliminate
the negative effects of toxics on human .
health and the environment.
To implement the goals of the
Governors' Agreement, the signatory
States directed their environmental
administrators to jointly develop an
agreement for coordinating the control
of toxic releases and achieving greater
uniformity of regulations governing
such releases within the Great Lakes
System. This coordinated effort between
the Great Lakes States contributed to the
development of the Great Lakes Water
Quality Initiative.
Finally, the Governors of the signatory
States committed to coordinate the
implementation of this agreement and to
review the progress made towards its
implementation on an annual basis. As
part of its role in implementing this
agreement, each jurisdiction agreed to
develop a management plan appropriate
to its own political and regulatory
system. The environmental
administrators of each State review
these plans annually.
D. Great Lakes Water Quality Initiative
1. Formation of Great Lakes Water
Quality Initiative
In June 1989, EPA's Region V initiated
the effort known as the Great Lakes
Water Quality Initiative. This effort was
, intended to provide a forum for State
and EPA development of uniform water
quality criteria and implementing
procedures for the Great Lakes basin.
The participants planned to use the
results of this effort as a basis for
revising State water quality standards
during the next triennial review period
required by section 303(c) of the CWA
and to negotiate revised Specific
Objectives and related protocols with
Canada under the GLWQA.
Three committees were formed under
the GLWQI. A Steering Committee; ;
consisting of directors of water
programs from EPA's national and
regional offices and the Great Lakes
States' environmental agencies (as co-
regulators of CWA water quality
programs), discussed policy, scientific,
and technical issues and directed the
work of the Technical Work Group. The
Technical Work Group (consisting of
technical staff from the Great Lakes
States' environmental agencies, EPA,
the U.S. Fish and Wildlife Service and
the U.S. National Park Service) prepared
proposals for submission to the Steering
Committee. The Public Participation
Group (consisting of representatives
from environmental groups,
municipalities, industry, and academia) .
observed the deliberations of the other
two groups, advised them of the public's
concerns, and kept its various
constituencies apprised of GLWQI
activities.
Of particular concern to the Steering
Committee were those pollutants which
persist throughout the Great Lakes
ecosystem and have a propensity to
bioaccumulate in the food chain,
thereby exhibiting or having the '
potential to exhibit systemwide impacts.
As discussed hi section LA. of this .
preamble above, although levels of
certain pollutants with systemwide
impacts have significantly declined in
recent years, the rate of decline has
diminished. Fish tissue concentrations
. of these pollutants have leveled off in
some cases, and may be approaching
equilibrium at concentrations well
above levels of concern as defined by
water quality criteria calculations.
Projections indicate that given the
current rate of pollutant loadings to the
Great Lakes System it will take many
years for fish tissue concentrations of
these highly bioaccumulative pollutants
to reach concentrations which allow
unrestricted consumption of Great Lakes
fish. State and EPA scientists believe
that this is the result of the unique
properties of the Great Lakes ecosystem.
The Steering Committee believed that
further reductions in loadings of such'
pollutants from all sources should be
pursued. Furthermore, the Steering
Committee was concerned that action be
taken to ensure that problems would not
develop in the future with pollutants
which show a propensity to
bioaccumulate and persist in the Great
Lakes ecosystem, thereby potentially
causing impairment of beneficial uses.
Therefore, the Steering Committee
initiated action by EPA and State staff
on the Technical Work Group to define
the persistent and bioaccumulative
pollutants that warrant additional
controls, and to develop proposed
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.' Federal Register A Vol. 58, No. 72 / Friday, Apnl 16^ 1993-7 Proposed Rules
20821
additional control approaches lor those
pollutants. v
To define the pollutants that warrant
additional controls, the Technical Work
Group considered two factors for
ranking and selection purposes:
Persistence and bioaccumulation.
—The persistence of a pollutant was
recognized as an important factor for
the reasons discussed in section LA of
this preamble. The Technical Work
Group believed, however, that
research to date does not suggest a
scientific approach that would allow
a systematic ranking of pollutants in
terms of their persistence in the Great
Lakes system. Persistence depends on
the cumulative effect of several fate
and effect processes, such as .
volatility, anaerobic degradation, ;
hydrolysis, and photolysis. The
Technical Work Group believed that '
systematic data were generally not
available for these individual , .
processes as they function in the
Great Lakes system. In addition, the
Technical Work Group believed that
data are not systematically available
concerning the cumulative effect of
individual fate.and effect processes on
specific pollutants in the Great Lakes
ecosystem under field conditions, or
- under laboratory conditions which
have been field correlated and -
verified.
—Bioaccumulation was recognized as
• an important factor because of its
ability to magnify the exposure ,of
.humans and wildlife to toxic ...
"pollutants. As discussed further in
sections n.G and IV of this preamble,
methods and data exist to allow
calculation1 of bioaccumulation factors.
(BAFs} for the 138 pollutants of initial
focus in the Great Lakes Water
Quality Initiative. The methodology ,
for developing BAFs provide for use
.of data collected under field , .
conditions or data collected under
laboratory conditions which have .
been field correlated and verified.
BAFs measure the uptake and -
retention of substances by organisms
from the water and the food chain,
and are expressed as the ratio of a
substance's concentration in tissue of
aquatic organisms to its concentration
in ambient water. . -.-...'...
The Technical Work Group proposed
utilizing a bioaccumulation factor
methodology which "incorporates
metabolism and other physicochemical
properties as a mechanism by which to
identify those pollutants which warrant
.additional controls. The Steering • ":
Committee agreed, and 'selected a
bioaccumulation factor (BAF) of 1000 as
an indicator of a pollutant's'ability to be
highly bioaccumulative, and .proposed
designating such pollutants as
bioaccumulative chemicals of concern
(BCCs). The selection of the BAF level
' of 1000 is discussed further in section
H.G below. Pollutants with a B AF'
greater than 1000 were believed by the
Steering Committee to have a high
potential to be found throughout the
food chain of the Great Lakes ecosystem
arid therefore to have the potential to
cause a significant risk to the health of
aquatic life, wildlife and humans which
inhabit the Great Lakes Basin. The
Steering Committee recognized that
metabolism, molecular size and other
physicochemical properties might effect
bioaccumulation. Therefore/the BAF
methodology being proposed in
appendix F of part 132 includes.
provisions for States and Tribes to "
consider these properties in developing
BAFs. -,~ ,
EPA and the Technical Work Group
recognize that using bioaccumulation
alone as a ranking and selection factor
is more conservative than considering
both persistence and biQaccumulation
together, since there may be highly
bioaccumulative pollutants that do not
persist long in the Great Lakes Basin
Ecosystem. The proposal to establish
additional, controls on chemicals with a
BAF over 1000 ensures that all
pollutants with both properties, '
persistence and bioaccumulation, will
be controlled.
EPA believes the selection of BCCs for
special attention in the Guidance is in
confbnnance with the Great Lakes Water
Quality Agreement, which calls for a
focus on persistent toxic pollutants.,
Article H of the Agreement states that it
is the policy of the parties to the
Agreemeritthat the discharge of any or :
all persistent toxic substances be
virtually eliminated, where persistent
toxic substances are defined in Annex
12 of the Agreement as any toxic
substance with a half-life in water of
greater than eight weeks. As discussed
above, the Technical Work Group was
unable to develop systematic
quantitative information, including
overall half lives, on persistence in the
.Great Lakes Basin Ecosystem. '
Nevertheless, in the professional
judgment of EPA scientists, the BCCs
identified in Part A of Table 6 of the
proposed Guidance are relatively ;
persistent in aquatic organisms and,
highly bioaccumulative. Therefore, they
would most likely qualify as persistent
toxic substances under the Agreement
EPA invites comment on the -approach
described above for selecting pollutants Y
for special attention in the Great Lakes •
System. In particular, EPA would like
^comments on the use of : ; -
bioaccumulation factors as the sole .•'•>•'•
quantitative factor to evaluate pollutants
tor special attention; comments on
whether data concerning other factors >
that reflect persistence as well as, Or
instead of, bioaccumulation should be
used to select pollutants; and if so, any
supporting data concerning overall
actual or estimated persistence in the
Great Lakes Basin Ecosystem, and -,
comments on what overall half life
should be used to select pollutants.
Furthermore, EPA would b& interested
in any data showing that a specific BCG
does not persist in the Great Lakes Basin
Ecosystem for at least the 8-week half,
life specified in the Great Lakes Water
"Quality Agreement, as measured by a
suitable" method of estimating overall
half lives. EPA invites comment on
whether such data should be used as the
basis for a possible exclusion of short-
lived pollutants from the definition of '
BCC. .-•-"•;-.
The Steering Committee judged that
every reasonable effort should be made
to reduce loadings of all BCCs. For
example, the Steering Committee
believed mixing zones should be
eliminated for BCCs as a way to reduce
mass loadings to the Great Lakes. In
particular, the Steering Committee was
concerned .that mixing zones on' large
tributaries not be used to allow , ,.
significant mass loadings of BCCs to the
Lakes. -- • -.'-• --.'. . '' ,: '
The Steering Committee believed that
new loadings of pollutants with a high
potential to bioaccumulate should be
severely restricted. Pollution prevention
approaches, which eliminate the •
generation of pollutants at the source :
, are inherently less costly than removing
pollutants once they have entered the '
environment. Accordingly, the Steering
Committee endorsed more stringent
antidegradation procedures for
pollutants with a high potential to
bioaccumulate. In addition, since many
of these pollutants are problematic even
when discharged below the level of
detection, due to their bioaccumulation
in the food chain to unsafe levels, the ,
Steering Committee believed -
dischargers of these pollutants should
conduct minimization programs to
eliminate the internal sources of these
.pollutants. Furthermore, the Steering
Committee reasoned that '
bioaecumulativexihemicals are those for
which surface water pathways are likely
to be major contributors to total human ~
exposure, and therefore the non-cancer
human health criteria-shouldbe',-'
adjusted throu'gh^use of a relative source
contribution (RSC) factor of 80 percent.
EPA is including the Steering, ; i
Committee's special regulatory .;•"-' :•
provisions for mixing zones, - • : •...
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20822 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
antidegradation, minimization
programs, and human health criteria
development for BCCs in the proposed
Guidance. Hie special regulatory
provisions include portions of the
human health criteria development
methodologies in appendix C, the
antidcgradation policy in appendix E,
and procedure 3 (total maximum daily
loads) and procedure 8 (WQBELs below
the levels of detection) in appendix F.
Discussions of these provisions are
provided hi sections V, VJH, VDI.E, and
VniH of this preamble. EPA believes
that the special requirements developed
by the Steering Committee are a
reasonable approach, although not
necessarily the only reasonable
approach to address the issue of
persistent bloaccumulative pollutants in
tho Great Lakes System, for the
following reasons:
—Persistence of toxic pollutants is a
major concern in an aquatic system
like the Great Lakes, for the reasons
discussed in section LA. above. It is
especially problematic for chemicals
that are highly bioaccumulative,
because the most important exposure
pathway for humans and wildlife in
the Groat Lakes System is
consumption offish and other aquatic
organisms. Persistent bioaccumulative
chemicals will result in high
exposures to humans and wildlife for
a long tune to come.
—-The proposed human health and
wildlife criteria may not be
sufficiently protective for persistent
bioaccumulative chemicals. The
proposed criteria are derived using
available data and assumptions
regarding data gaps. Despite the
inherently conservative nature of the
assumptions used when data gaps
occur, it is possible that in some cases
the criteria may not be sufficiently
stringent Considering the
conservative elements of the criteria
development methodologies, the risk
of criteria not being sufficiently
stringent is acceptable with respect to
pollutants that are not persistent in
tho environment, since the resulting
unacceptable impacts will be
relatively temporary in duration. For
persistent bioaccumulative pollutants,
however, the risk may not be
acceptable in the Great Lakes Basin
Ecosystem where recycling of
pollutants in a relatively closed
system may result in unacceptable
impacts that are long term in
duration, and make future cleanup
actions moro difficult, costly, and
time consuming. Accordingly,
additional controls intended to
prevent concentrations of persistent
bioaccumulative pollutants from
increasing to the level of criteria
concentrations in Great Lakes waters
are reasonable.
-Both options for development of total
maximum daily loads proposed in the
Guidance envision predominant use
of a simple, steady-state mass balance
approach. A mass balance approach is
a method used to approximate the
mass of pollutants within a. water
body. This approach assumes that the
input of mass into the system (e.g.,
through point and nonpoint source
loadings, atmospheric deposition,
groundwater seepage) equals the loss
of mass from the system plus any
losses due to transformation of mass
within the system. Because both
options assume a simple steady state,
it is assumed that no mass can be
accumulated in the system. This
provides for a first approximation of
allowable loading allocations. For
persistent bioaccumulative pollutants,
however, this approximation will
likely not be accurate. As discussed hi
section LA of this preamble above,
there are significant interactive
physical, chemical, and biological
processes' that affect the long-term
behavior of persistent
bioaccumulative pollutants in the
Great Lakes system, resulting in fairly
common occurrences where such
pollutants do accumulate in various
compartments in the system. The
proposed TMDL procedures provide
for subsequent monitoring to identify
any shortcomings in the control
approach and provide for appropriate
revisions. For persistent . -.
bioaccumulative pollutants, however,
this approach may present a
significant risk of allowing the
pollutants to concentrate in the
ecosystem above ambient criteria
levels before the control approach can
be revised and cleanup actions take
full effect EPA believes the costs of
future remediation actions to address
BCCs would be significantly more
expensive than efforts to control the
BCCs before they enter the
environment.Accordingly, additional
controls intended to prevent
concentrations of persistent
bioaccumulative pollutants from
increasing to the level of criteria
concentrations in Great Lakes waters
are reasonable.
-The proposed Guidance contains no
regulatory text concerning the
additivity of the toxic effects of
pollutants, although the preamble
discusses several approaches that EPA
may decide to include in the final
rule. T&the extent that the final rule
contains no provisions that directly
address risks related to additivity, or
contains provisions that directly
address some but not all aspects of
additivity, additional controls
intended to prevent cbncentrations of
persistent bioaccumulative pollutants
from increasing to the level of criteria
concentrations in Great Lakes waters
are reasonable to account for their
possible additive effects. For
persistent bioaccumulative pollutants
any additional effects would be more
difficult to overcome because of the
longer times required to identify
problems, establish controls, and
implement the controls, and for the
ecosystem to respond, ultimately
restoring beneficial uses.
The proposed Guidance calling for
special, more restrictive measures for
BCCs which could cause lakewide
impairments of beneficial uses is
consistent with the Great Lakes Water
Quality Agreement goal of virtual
elimination of toxics, the
recommendation of the Great Lakes
Governors Toxic Substances Control
Agreement calling for the continued
reduction of toxics in the Great Lakes
System to the maximum extent possible,
and the Clean Water Act goal of fishable
waters. The elimination of mixing zones
for BCCs in the Great Lakes system is '
consistent with current National
regulations and guidance and the Great
Lakes Water Quality Agreement. EPA
regulations provide that States may, at
their discretion, provide for mixing
zones as part of their State water quality
standards. EPA's 1991 guidance
document, "Technical Support
Document for Water Quality-based
Toxics Control," recommends that
States provide a definitive statement in
their water quality standards as to
whether or not mixing zones are
allowed and states that as our
understanding of pollutant impacts on
ecological systems evolves, there may be
cases identified where mixing zones are
not appropriate and should not be
allowed. The Great Lakes Water Quality
Agreement supports the elimination of
point source impact zones (mixing
zones) for toxic substances (GLWQA at.
Annex 2 Paragraph 2.(d)).
EPA invites comments on these
issues. EPA recognizes that there may be
other reasonable approaches to protect
the Great Lakes ecosystem from the
effects of persistent bioaccumulative
pollutants. For example, it may be
possible to devise a comprehensive
system of monitoring and special
NPDES .permit requirements to guard
against file buildup of such chemicals
past the point where the regulatory
control pro'cess can prevent levels from
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Federal Register /Vol. 58, No. 72 /Friday, April 16, 1993 /Proposed Rifles .' % 20823
exceeding criteria in the future because
of interactive processes and effects in
the relatively, closed Great Lakes Basin
Ecosystem. EPA invites comments on
such possible alternatives, how effective
they may be in addressing the types of.
problems discussed above, and how
easily they may be implemented.
^Further discussion of the definition of
BCCs, the selection process for the BCCs
listed in Parts A andB of Ta~ble 6 of part
132 of the proposed Guidance, and an
invitation for comments on specific
issues is found in section E.G. below. A
more detailed discussion of the special
regulatory requirements^mposed on
• BCCs is found in sections II. G, VII,
yffl.C, and VHLE of this preamble,
below,-
2. Great Lakes Critical Programs Act of
1990 • : .---.,..
/The above efforts by the Great Lakes
Water Quality Initiative were well
underway in 1990 when Congress
passed the Great Lakes Critical Programs
Act (CPA). In developing this
legislation, Congress praised the
ongoing efforts of the Initiative to
develop guidance on minimum
requirements for the Great Lakes States'
water quality programs. 136-Cong. Rec.
S. 15620,15623 (Oct. 17,1990)
(Remarks of Senator Levin). (See also
" discussion of legislative history in
section H.E.l.c. below.) Congress .c
amended section 118 of the Clean Water
Act through the Great Lakes Critical
Programs Act of 1990 (CPA) (Public Law
101-596, Nov. 16,1990). The general .
purpose of these amendments was to
improve the effectiveness of EPA's
existing programs in, the Great Lakes by
identifying key treaty agreements
between the United States and Canada
in the Great Lakes Water Quality .
Agreement, imposing statutory"
deadlines for the implementation of
these key activities, and increasing
federal resources for program operations
in the Great Lakes System. (W.).
Section .101 of the CPA (Clean Water
Act section 118(c)(2)) requires EPA to
publish proposed water quality
guidance for the Great Lakes System
which conforms with the objectives and
provisions of the GLWQA and is no less
restrictive than provisions .of the Clean •
Water Act and national water quality
criteria and guidance. The guidance
must specify minimum requirements for
the waters in the Great Lakes System in
three areas:
a. Water quality standards (including
numerical limits on pollutants in
ambient Great Lakes'waters to protect -'..
human health, aquatic life and wildlife);
b. Antidegradation policies; and
c. Implementation procedures,
The CPA amendments require the
Great Lakes States to adopt water
quality standards, antidegradation
policies-and implementation procedures
for waters within the Great Lakes
System which are consistent with the
. finarguidance. If a State fails to adopt :,
• consistent provisions within two years
of EPA's publication of the'final
" guidance, EPA is required to promulgate
any necessary requirements for the State
within that two-year period. The
proposed procedure for State and Tribal
adoption of these provisions is set forth
in section n below. . " ' •'
. The statutory requirements to develop
guidance for the Great Lakes were
intended to codify the ongoing efforts of
EPA and the eight Great Lakes States
under the Great Lakes Water Quality
Initiative. 136 Cong. Rec. S. 15620,
15624 (Oct. 17,1990) (remarks of Sen.
Levin and Sen. Glenn) Congress
recognized that a primary goal of the
Great Lakes Water Quality Initiative was
to identify, through a regional dialogue,
minimum guidelines to reduce .',_•-''
•disparities among water quality controls
in the Great Lakes. Congress intended
that the Great Lakes Guidance would
similarly move the Great Lakes States
toward a more consistent, region-wide
implementation of the GLWQA by
addressing "the topics already under
discussion in the region: Minimum
water quality standards for selected
pollutants, antidegradation policies and
implementation procedures.''-(Id.) As
discussed further in section H.E.l.c.
below, the establishment of a more ,-
uniform control of water pollution in
the Great Lakes System was one of the"
most important goals of this legislation.
In addition to the requirement to"..
develop the Great Lakes Water Quality
Guidance in the proposed Guidance, the
1990 amendments to section 118
specified requirements for several other
ongoing EPA programs in the Great
Lakes. For example, the amendments
also included requirements or'-'deadlines
for research on contaminated sediments;
.development of numerical sediment
criteria; development of a Lakewide
Management Plan for Lake Michigan ,
and Remedial Action Plans for Areas of
Concern; development of management •
plans for confined disposal facilities;
and the assessment of spills of oil and
hazardous materials in the Great Lakes.
These, as well as other, separate EPA
and State programs to address water
quality problems in the Great Lakes
System, are addressed in section G
below. .-"• -
3. Process After the CPA ,
, Following the passage of the Great
Lakes Critical Programs Act of 1990.
EPA and the eight Great Lakes States
intensified efforts on the Great Lakes
Water Quality Guidance. On December
6,1991, the GLWQI Steering Committee,
recommended unanimously that EPA
publish the proposed Great Lakes
Guidance as approved by the Steering
'. Committee in the Federal Register for
public comment. The agreement that the
Great Lakes Guidance ,was ready for
public notice did not represent an' '
endorsement by every State of all of the
specific proposals. EachState indicated
its intention to fully review the
proposed Great Lakes Water Quality .
Guidance and submit specific comments
during the public comment period.
EPA has generally used the December
6,1991, Steering Committee proposal as
the basis for the proposed Guidance. •
However, the. proposed rule contains a
number of substantive clarifications,
additions, and modifications to the
Guidance endorsed by the GLWQI
/Steering Committee to reflect statutory
and regulatory requirements, or EPA
policy considerations. In addition, EPA
has reorganized and modified the
Steering Committee proposal for ,
publication in the Federal Register, and,
added proposed regulatory requirements
and procedures for State and Tribal
adoption of the final Guidance. All
sections of the Guidance approved by
the Steering Committee on December 6,
1991 are either incorporated in the
proposed Guidance or discussed hi the
preamble. ~
The Great Lakes States'requested the
opportunity to provide EPA with their,
views on the public comments * '
submitted on the proposed Guidance. '
Accordingly, following the close of the
public comment period, EPA intends to
compile the public comments and hold
an open public meeting for the'purpose
of receiving the vie.ws of both the Great
Lakes States and other members of the
public on the written comments. The
date, time and location of the public
meeting will be published in the.
Federal Register and'a summary of the
meeting will be included in the public
docket. ' : '
E. Elements of the Guidance
1. Water Quality Criteria for the
Protection of Aquatic Life
The Guidance proposes numeric
criteria to protect aquatic life for 16
pollutants, and a two-tiered
methodology to derive criteria and
yalues_for additional pollutants
discharged to the Great Lakes System.
Aquatic life criteria are derived to . •
establish ambient concentrations for
pollutants, which, if not exceeded in the
Great Lakes System, will protect fish,
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20824
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
benthic organisms, and other aquatic
Ufa from impacts due to that pollutant
EPA is proposing an acute criterion and
a chronic criterion for most of the 16
pollutants specifically addressed today.
An acute criterion indicates the
maximum concentration which, if not
exceeded, will protect organisms in the
Great Lakes System from short duration
exposures. They apply in all parts of the
Great Lakes System, including areas
near points of discharge where physical *
mixing of discharge water and receiving
water occurs. A chronic criterion
indicates the maximum concentration
which, if not exceeded, will protect
organisms in the Great Lakes System
from long duration exposures. Chronic
criteria do not generally apply to areas
near discharge points where mixing
occurs. The acute criteria proposed are
set at a higher concentration than
chronic criteria.
Aquatic life criteria for each chemical
are primarily based on laboratory
toxicity data for a variety of aquatic
species (e.g., fish, benthic invertebrates,
plants) which are representative of the
spcclos in the environment as a whole.
In some cases, the proposed Tier I
numeric criteria include more current
toxicity data than existing National
criteria guidance due to the availability
of more recent data. The Great Lakes
Water Quality Guidance also proposes a
translator procedure (the Tier n
methodology) to develop water quality-
basfld effluent limitations for NPDES
permits in the absence of the full Tier
I data requirements. The Great Lakes
States and Tribes are not required or
encouraged to use the Tier E
methodology to adopt water quality
criteria under section 303 of the Clean
Water Act States must use the Tier n
methodologies, however, in conjunction
with the proposed whole effluent
toxicity requirements to implement
their existing narrative toxics criteria in
the absence of data necessary to derive
water quality criteria or numerical
effluent limitations under the proposed
Tier I methodologies.
The above-mentioned procedures
result in two tiers of aquatic life
protection and allow the application of
the Great Lakes Water Quality Guidance
to all pollutants, except those listed in
Table 5 of this proposal* Tier I numeric
criteria are based on data requirements
very similar to those used in current
National guidance, i.e., acceptable
toxicity data for aquatic species in at
least eight families which represent
differing habitats and taxonomic groups
must exist before a Tier I numeric '
criterion can be derived. Tier n values
are used when the minimum Tier I data
requirements are not met, but a value
equivalent to a water quality criterion •
needs to be derived in order to make the
permitting and control decisions
necessary to address a pollutant
discharge- Tier II values can, in certain
instances, be based on toxicity data from
a single taxonomic family.
2. Water Quality Criteria for the
Protection of Human Health
The Guidance'proposes numeric
criteria to protect human health for 20
pollutants and a methodology to derive
cancer and non-cancer human health
criteria and values for additional
pollutants discharged to the Great Lakes
System. Human health criteria are
derived to establish ambient
concentrations of chemicals which, if
not exceeded in the Great Lakes System,
will protect individuals from adverse
health impacts from that chemical due
to consumption of aquatic organisms
and water, including incidental water
consumption related to recreational
activities in the Great Lakes System. For
each chemical, chronic criteria are
derived to reflect long-term
consumption of food and water from the
Great Lakes System.
As with the aquatic life criteria
procedure, the human health procedure
results in two tiers of numeric values:
Tier I numeric criteria and Tier n
values. For Tier I numeric criteria, dose-
response data are derived from human
or animal studies which are associated
with no observable toxic effect. Studies
are evaluated for both carcinogenic and
non-carcinogenic effects. Numeric
criteria are calculated by integrating an
assessment of the relationship between
the dose of a chemical and the potential
for causing an adverse effect with
appropriate exposure assumptions
based on data from the Great Lakes
System for consumption of fish,
bioaccumulation in fish, and
consumption of water, to yield an
ambient water concentration that is not
likely to result in adverse human health
effects over the course of a human
lifetime.
Under the Tier n procedures, Tier n
values will be established for chemicals
with an insufficient database to meet
Tier I requirements. Tier E values may
he-established for non-carcinogenic and
carcinogenic endpoints depending on
the adequacy of data.
The Great Lakes Water Quality
Guidance differs from current National
water quality guidance by using
bioaccumulation factors which account
for direct uptake from the waters of die
Great Lakes System plus uptake from
the fopd chain. This consideration often
results in the development of more
stringent criteria. Additionally, a fish
consumption rate that is based on data .
from the Great Lakes area is used in the
proposed Guidance. This value is higher
than that used in the National guidance.
This results in more accurate and
protective, although more stringent,
criteria that appropriately reflect Great
Lakes fish consumption rates.
3. Water Quality Criteria for the
Protection of Wildlife
The Guidance proposes numeric
criteria to protect Wildlife for four -
pollutants and a methodology to derive
criteria and values for additional
pollutants discharged to the Great Lakes
System. Wildlife criteria are derived to
establish ambient concentrations of
chemicals which, if not exceeded, will
protect mammals and birds from
adverse impacts-from that chemical due
to consumption of food and/or water
from the Great Lakes System. The Great
Lakes wildlife criteria are the highest
calculated aqueous concentrations of
substances which cause no significant '
reduction in growth, reproduction,
viability or usefulness of a population of
exposed animals that use Great Lakes
System waters for food or drinking over
several generations. For most chemicals
of concern, piscivorous wildlife species
have been identified as most at risk .
within the Great Lakes System. Based
on an analysis of body size and foraging
behavior for wildlife in'the Great Lakes
System, the mink and river otter, and
the eagle, osprey, and belted kingfisher
have been selected as representative
mammalian and avian species for
calculating these criteria.
For each chemical, only a chronic
criterion is derived in the Great Lakes
Water Quality Guidance because
adverse effects to wildlife normally
occur only over relatively long periods
of time through continued periodic
exposure to contaminated food and
water from the Great Lakes System.
The wildlife procedure results in the
same type of two-tier protection as the
aquatic life and human heaUh
procedures. Tier I numeric criteria are
based on dose response data from birds
and mammals. Either field studies or
laboratory studies serve as sources of
data. Tier n values may be based on data
from a single taxonomic class, and may
come from laboratory studies of more
limited scope for mammals. For birds,
studies must meet the same
requirements as for Tier I.
The development of wildlife criteria
procedures within the Great Lakes
Water Quality Guidance is a significant
addition to current national guidance as
EPA has not published a separate
wildlife criteria methodology at the
National level. Only four numeric
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20825
, wildlife criteria are being proposed for i
two major reasons: Field studies from
the Great Lakes indicate that the* four :
pollutants for which wildlife criteria are
proposed have had the most severe
impacts on wildlife within the Great
Lakes; and the criteria proposed are the
first set of criteria for wildlife that EPA
has ever developed. EPA cannot take
advantage of an established and peer-
reviewed national methodology to
develop wildlife criteria as it can for •
both human health and aquatic life .
criteria; The Initiative Committees and
EPA lacked time and resources to
develop additional numeric criteria for
wildlife prior to this proposal. The State
of Wisconsin had already identified
these four chemicals as chemicals of
concern for wildlifei impacts in their
State and completed, literature reviews,
for these four chemicals. These i
literature reviews were updated as part
of the GLWQI effort.
4. Bioaccumulation Factors
The Great Lakes Water Quality
.Guidance contains a procedure for
determining bioaccumulation factors
which are used to estimate the intake of
. chemicals via consumption of fish by
wildlife species and humans. The Great
Lakes Water Quality,Guidance proposes .
to use bioaccumulation factors in the
calculation of wildlife criteria and
human health criteria to account for the
tendency of organisms to accumulate
. certain chemicals hi their tissues to
'-'• concentrations many times greater than
the concentration of the chemical in the
water body. For certain chemicals, this
tendency to bioaccumulate becomes
' more pronounced with every level of
the food chain through which the '
chemical passes. To protect species at
all levels of the food chain requires
relatively stringent criteria for those
chemicals which bioaccumulate in , "'-
organisms. Bioaccumulation factors are
generally higher than the ,
bioconcentration.factors currently in use
by most States and EPA in deriving.
water quality criteria to protect human
health. This is due to the fact theit
bioconcentration accounts only for
: uptake by aquatic organisms directly
from water alone, while
bioaccumulation factors account for
accumulation through die food chain.
The bioaccumulation.factor used in
the calculation of human health criteria
in the Great Lakes Guidance is different
.from the one used to calculate the V
wildlife criteria for any given chemical.
This is due to the type and form of food
eaten by wildlife (whole body), which is
different from that typically eaten by
people (muscle tissue alone). Since,
many chemicals, of concern tend to
bioaccumulate in fat more than other
tissues, the bioaccumulation factor used
" in calculating human health criteria will
in many cases be lower than the one ,
used in calculating wildlife criteria.
Also, significant differences in the types
of species consumed by wildlife versus
those consumed by people'may also '
, affect the bioaccumulation factor used
in calculating human health criteria
versus wildlife criteria for the Great
Lakes System.
5. Antidegradation ,
The.Great Lakes Guidance
antidegradation policy is intended to
protect and maintain existing water
quality. The concept was developed in
the regulatory context as early_as 1968
by the Department of Interior and is
included in federal regulations (40 CFR
131.12) and reflected in the Clean Water
Act. However, specific National
guidance on implementation of this
concept within the context of current
regulatory programs (e.g., NPDES
permits) has never been developed,
resulting in a myriad of State
implementation procedures with
various levels of protection. •
The Great Lakes Water Quality
Guidance proposes detailed
antidegradation Implementation
guidance'to ensure that all of the States
and Tribes in the Great Lakes System
carry out this important water quality
concept in a consistent and protective ;
manneri Antidegradation provides three
different levels of protection, depending
on the water quality in the receiving
water body. First, for all water bodies,
water quality cannot be degraded below
the level protecting existing uses, which
are defined as any uses that a water
body has actually supported since 1975.
If a water body has supported, for
example, a fishery at any time since •
1975—'Whether or not the fishery is still
in existence—no chemical can be
discharged at a level that would impact
the water quality needed for a fishery,
even if allowing the discharge would be
socially and economically important to
the community,. . ./ • .
Second, if the water body is not an"
OutstandingNational Resource Water .
(ONRW), but ambient water quality is ,
better than the quality needed for
fishable/swiirimable uses for any given
chemical, then significant increased
loadings of that chemical are allowed
only if the State or Tribe determines that
it is necessary for important social and .
economic development in the area
where the.increase is proposed. The
Great Lakes Water Quality Guidance
antidegradation procedures specify how
Great Lakes States or Tribes will
determine when a proposed action, such
as an NPDES permitted'discharge, will
result in significant lowering of water
..quality in the water body; whether it is
necessary for that action to significantly
lower Water quality, and how the socio-
economic importance of such an action:
will be evaluated. In general, NPDES
permit conditions for chemicals .which
bioaccumulate will restrict dischargers
to the loadings currently measured in
their effluent, unless the discharger
demonstrates the need to accommodate
important social and economic
development. .'"' •'" ••
Third, if a State or Tribe has
. designated a water body as an '
Outstanding National Resource Water
(ONRW), then no permanent
degradation is allowed under any
circumstances.
6. Implementation Procedures. _
In addition to the water quality '
criteria and antidegradation policies •
discussed above, the proposed Guidance
includes procedures to convert water
quality criteria and values into specific
controls on sources of pollutants in the
Great Lakes System. Various procedures
to implement State numeric and
narrative water quality criteria are
currently contained in EPA regulations
and guidance and in individual State
water quality standards or NPDES
programs authorized under section 402
of the Clean Water Act.
The 1990 amendments to section
118(c)(3) require EPA to publish
guidance, on Tnininrmnv implementation
procedures for the Great Lakes System.
One of the mpst important goals of this
legislation was the establishment of a
more uniform level of control of water
pollution by the Great Lakes States.
Consistent procedures to translate water:
quality criteria into specific controls on
pollutant sources are essential to this :"-.
goal.
Appendix F of the proposed Guidance
specifies minimum requirements for '.,"••
procedures to implement water quality
criteria in the following areas:
a. Site-specific modifications tb~
criteria/values (implementation •
procedure 1 of appendix F to part 132);
'b. Variances from water quality ;
standards (implementation procedure 2
of appendix F to part 132);
c. Total maximum daily load/
wasteload allocation procedures/mixing
zones for point sources;:(implementation
procedure 3 of appendix F to part 132);
d. Additivity (implementation
procedure 4 of appendix F to part 132,
which is reserved in the proposed
Guidance); ••'••-.
e. Reasonable potential to exceed
numeric water quality/standards '.'.-."
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(implementation procedure 5 of
appendix F to part 132);
f. Whole effluent toxicity
requirements (implementation
procedure 6 of appendix F to part 132);
g. Loading limits (implementation
procedure 7 of appendix F to part 132);
h. Water quality-based effluent
limitations below the levels of detection
(implementation procedure 8 of
appendix F to part 132); and
i. Compliance schedules
(implementation procedure 9 of
appendix F to part 132).
F. Science Advisory Board Review
The EPA Science Advisory Board
(SAB) was established to provide
independent advice to EPA on the
scientific and technical aspects of
environmental problems and issues.
(Sao Environmental Research,
Development and Demonstration Act of
1978,42 U.S.C. 4365.) EPA submitted
the draft proposals developed by the
Great Lakes Water Quality Initiative
Steering Committee for the aquatic life
methodologies, the wildlife
methodologies, the human health
methodologies, and the
bioaccumulation methodology to the
SAB for review on January 8,1992. EPA
generally used the Steering Committee
proposal as the basis for developing the
Great Lakes Water Quality Guidance
proposed by EPA. EPA requested SAB
review of these draft documents due to
their scientific and technical complexity
and potential effect on EPA's current
National guidance in these areas.
The SAB completed its review of
those draft documents on December 16,
1992. A copy of the SAB report (EPA-
SAB-EPEC/DWC-93-005) is contained
in the public docket of this rulemaking.
The report was prepared jointly by the
SAB's Great Lakes Water Quality
Subcommittee of the Ecological
Processes and Effects Committee and
the Drinking Water Committee. The
SAB commended EPA for the
interactions among the States, EPA, the
private sector and the scientific
community during the development of
this proposed Guidance and provided
substantial comments on many elements
of the submitted draft documents. Some
of the questions and comments raised in
the SAB review were identified by EPA
during the subsequent preparation of
the proposed Guidance, and resulted in
modifications to the proposed rule. The
remaining major issues raised by the
SAB have been highlighted by EPA in
the appropriate preamble sections to
solicit full public review and comment.
G. Other Programs to Protect and
Restore the Great Lakes
In addition to the Great Lakes Water
Quality Guidance described in the
proposed Guidance, the United States is
currently implementing several
regulatory and voluntary programs to
prevent pollutants from being
introduced, reduce pollutant loadings
currently being discharged, and
remediate the adverse effects associated
with past pollutant discharges to the
Great Lakes System. Several of these
programs are described below.
1. Great Lakes Five-Year Strategy
The EPA and 15 Federal, State and
Tribal agencies have developed a Five-
Year multi-media Strategy-to reduce
toxic loadings from all sources of
pollution hi the Great Lakes System
("Protecting the Great Lakes: Our
Environmental Goals and How We Plan
to Achieve Them," USEPA, April 1992).
The goals of this inter-agency Strategy
are to: * -
a. Reduce and virtually eliminate
toxic substances in the Great Lakes
Basin Ecosystem;
b. Protect and restore habitats vital for
support of healthy and diverse
communities of plants, fish and
wildlife; and
c. Ensure the protection of human
health while restoring and maintaining
the biological diversity among Great
Lakes fish, aquatic life, wildlife and
plants.
The Strategy includes specific
commitments and activities that will be
coordinated among the Federal, State
and Tribal agencies to achieve these
common environmental goals. For
example, elements of the Strategy
include: Implementation of the Clean
Air Act Amendments to reduce
atmospheric deposition of toxics;
application of the National
Contaminated Sediment Strategy to
assess, prevent and remediate
contaminated sediments; measures to
implement best management practices
to control runoffs from such diffuse
sources as agriculture, silviculture,
mining and construction sites; and the
coordinated development of agency and
State work plans to target actions on
specific pollutants of concern in the
Great Lakes System.
2. Great Lakes Pollution Preventior
Action Plan
The Pollution Prevention Act of 1990
declares as National policy that ,
pollution prevention is the preferred
approach to environmental protection:
reducing or eliminating pollution
through, for instance, changes in
production processes and/or by
reducing reliance' on environmentally
harmful materials. (Pub. L. 101-508,
section 6601-6610,104 Stat. 1388,
codified at section 13101-13109 West
Supp. 1991). When preventing pollution
is not feasible, recycling in an
environmentally safe manner is the next
preferred option, followed by treatment.
Disposal or other release into the
environment should be the management
option of last resort, and should only be
done in an environmentally protective
manner.
Consistent with the goals of the
Pollution Prevention Act, EPA
developed the Great Lakes Pollution
Prevention Action Plan (April,11991).
The Action Plan highlights how. EPA, in
partnership with the States, will
incorporate pollution prevention into
actions to reduce the use and release of
toxic substances in the Great Lakes
basin. These activities are designed to
complement efforts already underway at
the State and Federal levels.
The Action Plan has two distinct
components. First, it includes new
initiatives designed to promote
. innovative pollution prevention __
practices throughout the basin. Second,
it involves reorienting and refocusing
existing activities, such as enforcement
actions, to ensure that pollution
prevention is an integral part of
government's environmental protection
.efforts. The Action Plan also builds
upon the National EPA Pollution
Prevention Strategy (56 FR 7849
(February 26,1991)). The focus of the
National strategy is to reduce the on-
going generation of toxic pollution in
any form (air emissions, waste water
discharges, hazardous waste, runoff, or
fugitive releases) through reduction in
the use of toxic substances, process
changes and product changes.
EPA and the Great Lakes States agreed
to implement this effort to reduce the
levels of toxic substances found in the
Great Lakes basin by promoting
pollution prevention activities to ,
significantly reduce or eliminate the use
and/or release of toxic substances at the
source, with a special focus on reducing
or eliminating persistent
bioaccumulative toxic substances. EPA
is currently promoting pollution
prevention through a number of
regulatory and non-regulatory activities.
For example, EPA is implementing the
National 33/50 Program in the Great
Lakes System. Under this National ,„
program, EPA has received voluntary
commitments from industry to reduce
the emission of 17 priority pollutants by
. 33 percent by the end of 1992 and by
50 percent by the end of 1995. EPA has
also been working with utilities located
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20827
within the Great Lakes basin to
accelerate the phase-out of transformers
containing PCBs; In addition, EPA and
the Great Lakes States have undertaken
many pollution prevention activities
including "clean sweeps" which not
'only provide, for the collection and ,
~ environmentally safe disposal of
contaminants, but also provide.
educational fact sheets to participants
on how to prevent future pollution, _•
These pollution prevention activities :
wiU complement other ongoing efforts
to reduce toxics in the Great Lakes
^ System. ' " '.•"': : ... •
3, Lakewide Management Plans (LaMPs)
In Article VI, Annex 2 ^of the Great
Lakes Water Quality Agreement
(GLWQA), as amended in 1987, the
United States and Canadian
Governments agreed to develop and ,
implement Lakewide Management Plans
• '(LaMPs) for each of the five Great Lakes.
LaMPs are management tools designed
to: (1) Integrate Federal, State and local
programs to reduce loadings of toxic
substances (including discharges from
point and nonpoint sources); (2) assess
whether these programs will ensure
. attainment of water quality standards
and designated beneficial uses; and (3)
recommend any media-specific program
enhancements necessary to reduce toxic
-loadings in waters currently not
attaining water quality standards and/or
designated beneficial uses. LaMPs
.provide an opportunity for regulatory
. authorities to design cost-effective
approaches for .meeting water quality
standards and/or beneficial .uses. .
The primary goal of the LaMPs is to
reduce loadings of critical pollutants,
those pollutants which are currently
impairing the beneficial uses of the
open waters of the Great Lakes. LaMPs
are also pollution preventionroriented
and address pollutants that might
impair waters that currently meet water
quality standards and/or beneficial .uses.
Traditional regulatory programs, as well
as non-traditional voluntary programs,
are considered in the LaMP process.
LaMPs for each of the Great Lakes will
be developed by EPA in phases; LaMP
development activities were initiated for
Lakes Michigan and Ontario in Federal
fiscal year 1991, and for Lake Superior
in fiscal year 1992. LaMPs for Lakes Erie
and Huron will be initiated in fiscal
years 1993 and 1994, respectively.
The Great Lakes Critical Programs Act
of 1990 (CPA) established deadlines
regarding the completion of the Lake
Michigan LaMP. A notice of availability
of the draft Lake Michigan LaMP was .
published in the Federal Register on
August 11,1992 (57 FR 358). Following
the public review and comment period,
the Lake Michigan LaMP will be revised
.and submitted to the International joint
Commission. The final Lake Michigan
LaMP will be published in the Federal
Register. The draft Lake Michigan LaMP
has identified both immediate and long-
term implementation actions to reduce
loadings of critical pollutants. Three
basic implementation steps are outlined:
identification of all possible sources of
pollutants; quantification of loadings
from each source; and identification of
load reduction activities with the
greatest potential for pollutant
reduction. •-- "..-••:.•
Development of the Lake Ontario
Toxics Management Han (LOTMP), the
precursor to me Lake Ontario LaMP,
was undertaken by EPA, Environment
Canada, the New York State Department
of Environmental Conservation and the .
Ontario Ministry of the Environment
(the Four Parties) on February 4,1987.
The goal of the LOTMP is to ensure a
Lake that provides drinking water and
fish that are safe for unlimited human "
consumption, and allows natural
reproduction within (the ecosystem of -.
the most sensitive native species
including bald eagles, ospreys, mink
and otters. The LOTMP addresses the
bioaccumulation of toxic chemicals in
fish flesh, the primary •environmental. ,
problem identified in Lake Ontario.
InitiaLtoxic reduction efforts are
focussed on 20 hazardous waste sites
that contribute .99 percent of the total
loadings of contaminants from waste
sites to the Niagara River which flows
into Lake Ontario.
The LaMP development effort for
Lake Superior began as a component of .
the Bi-National Program to Restore and
Protect the Lake Superior Basin. Lake.
Superior has not experienced the
intense development, urbanization and
pollution characteristic of the lower
lakes and has remained relatively :
pristine. The focus of the Lake Superior
LaMP.-therefore, is on using Lake
Superior as a demonstration area for
new and innovative approaches to
pollution prevention and zero
discharge. ' •
EPA intends to periodically update
LaMPs to reflect progress in
implementing media-specific programs
and attendantreductions in toxic
loadings, to incorporate advances in the
understanding of the Great Lakes
System.based on new data and
information, and to include any .
necessary program specific adjustments.
In addition, EPA expects any new ,
loadings data obtained during the LaMP
process will be nlcorporated by the
States when establishing or revising
TMDLs and WLAs in the Great Lakes
System. These new TMDLs and WLAs
will then be appropriately reflected in
subsequent revisions to NPDES permits.
4. Remedial Action Plans (RAPs)
The development and implementation
of Remedial Action Plans (RAPs) is
addressed in. Annex 2 of the Great Lakes
. Water Quality Agreement. This section
provides that United States and
Canadian Governments will cooperate '
with State and Provincial Governments -
to ensure that RAPs are developed and
implemented for specific Areas of
Concern (AOCs) in the Great Lakes. -
• Forty-three AOCsiave been '
designated by the United States and/or
Canadian Governments: 26 located
entirely within the United States; 12 V
located wholly within Canada; and five
that are shared by both countries. RAPs
are being developed for each of these
AOCs that are designed to address
impairments to any one of 14 beneficial
uses (e.g., restrictions on fish and
wildlife consumption, dredging
activities, or drinking water . ;
consumption) associated with these ,
"areas, . : .--""' ' - . '--. ; ,
RAPs are developed in three stages:
The assessment of use impairments, the
stresses and sources of the stresses in
Areas of Concern (Stage I); proposed
remedial actions1 and their method of
implementation {Stage H); and evidence
that uses have been restored (Stage IE),
including significant milestones hi the
restoration of beneficial uses in the .
AOCs. The eight Great Lakes States and
the Province of Ontario have the lea&in
preparing and implementing the RAPs,
but rely on the input and expertise
provided by Federal agencies and
organizations as well as local citizens
groups and individuals. The Great Lakes
Critical Programs Act of 1990 ; .
established deadlines for.completion of
RAPs for all AOCs in the United States.
As a result, the pace of RAP
development has been accelerated.
Remedial actions to restore impaired
Uses in AOCs are proceeding in all of
the" designated AOCs even if RAP - •..;."
documents have not been fully
completed. For example, State and
Federal enforcement actions have been ,
taken against industrial dischargers for
permit violations. Multi-year programs
to eliminate or treat combined sewer
overflows and upgrades to municipal
sewage treatment plants have been
undertaken by cities and municipalities.
Superfund cleanups are in progress and
EPA and the States have taken multiple
remedial actions through hazardous <'•-•;•
waste programs. Additionally, Federal :'
and State agricultural pollution control
programs are'alsp addressing problems
in several AOCs. ••','<•• .
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5. Contaminated Sediments
The United States and Canadian
Governments, in cooperation with State
and Provincial governments, have
agreed to identify the nature and extent
of sediment pollution in the Great Lakes
System pursuant to Annex 14 of the
Groat Lakes Water Quality Agreement.
Based on these findings, the United
States and Canada have agreed to
develop methods to evaluate both the
impact of polluted sediments on the
System and the technological
capabilities of programs to remedy such
pollution. Information obtained through
research and studies pursuant to Annex
14 will also be used to guide the
development and implementation of
RAPs and LaMPs. EPA is developing
both National and Great Lakes-specific
strategies to deal with this source of
contamination hi a comprehensive and
systematic way.
Contaminated sediments are a
significant source of loadings of toxic
pollutants at harbors and river mouths
throughout the Great Lakes System and
identified as environmental problems hi
42 of the 43 AOCs. Based on a
preliminary review of Superfund case
studies (including the Fieldbrook
Superfund site in Ashtabula, Ohio), the
benefits of remediating contaminated
sediments are similar to, or exceed, the
costs even when considering only the
benefits of avoiding human cancer from
consumption of contaminated fish. If
economic values could also be assigned
to the values of noncancer health effects
and the negative ecological effects, the
benefits would be even greater.
In order to design appropriate, cost-
effective remediation measures,
information at each site is needed on the
distribution and surface area of
contaminated sediments, their depth
and volume, chemicals present, toxicity
of the chemicals, potential for sediment
transport and redistribution, and the
movement of the chemicals from the
sediments to the water and to aquatic
communities.
Tho 1987 Clean Water Act authorized
a five-year demonstration program to
develop technologies to treat
contaminated sediments in the Great
Lakes. This program, known as the
Assessment and Remediation of
Contaminated Sediments (ARCS)
Program, is designed to evaluate
appropriate treatment methodologies for
the cleanup of toxic pollutants in Great
Lakes contaminated sediments. The IJC
has identified contaminated sediments
as a problem in 42 out of 43 United
States and Canadian AOCs.
Additionally, EPA and local RAP teams
havo cited contaminated sediments as a
problem in all 31 United States and
joint United States/Canadian AOCs.
Under this program, United States
demonstrations of alternative treatment
technologies are underway.
The ARCS Program has used an
integrated approach involving over 40
agencies and organizations in
developing and testing assessment and
remedial action alternatives for
contaminated sediments. The overall
objectives of the ARCS Program are to:
Develop and demonstrate tools and
approaches for assessing the nature and
extent of bottom sediment
contamination at selected Great Lakes
AOCs; develop tools to predict the
consequences of remedial actions being
proposed; and demonstrate and evaluate
the effectiveness of selected remedial .
options, including removal,
immobilization and advanced treatment
technologies. "
This Program demonstrates state-of-
the-art methods for the assessment of
contaminated sediments. A mass
balance approach is being applied to
assess all impacts within an AOC and to
predict the benefits from a range of
cleanup scenarios. Both bench and on-
site pilot demonstrations are being
conducted at five priority AOCs in order
to evaluate different assessment and
remediation options and to provide
environmental decision-makers with ,
guidance on how to eh'minate problems
posed by contaminated sediments, Final
guidance documents on field
assessments, risk assessments and
modeling, and remedial technologies
will provide guidance for future, full-
scale cleanup efforts.
EPA is preparing to publish for public
comment proposed sediment quality
criteria for acenaphthene, dieldrin,
endrin, fluoranthene, and
phenanthrene. EPA is also developing a
National Contaminated Sediment <
Strategy, which is expected to include
comprehensive strategies on sediment
assessment, prevention, remediation,
and dredged material management.
EPA's draft nationwide contaminated
sediment management strategy proposes
the use of four statutes (the
Comprehensive Environmental
Response, Compensation, and Liability
Act, the Resource Conservation and
Recovery Act, the Toxic Substances
Control Act, and the Clean Water Act)
to achieve active remediation of
contaminated sediments. The Great
Lakes ARCS Program is an essential
component of the National Strategy.
Implementation of the strategy will
provide reductions in loadings of
pollutants impairing water quality of the
Great Lakes System and preventing
attainment of beneficial uses.
In the assessment strategy, EPA is
proposing to develop a national
inventory of contaminated sediment
sites and a pilot inventory of potential
sources of sediment contamination,
based on data from the ARCS Program
as well as on other databases. The
inventories will enable EPA's
prevention and remediation programs to
focus resources on addressing top
priority sites and sources. The
assessment strategy proposes to develop
a consistent, tiered testing, protocol that
will include a minimum set of chemical
and biological methods that all EPA
programs will use to determine if . ..
sediments are contaminated. EPA is also
developing sediment chemical criteria
to be used in sediment assessment. The
prevention strategy discusses a variety
of pollution prevention measures and
source controls, including nationally
applicable responses, such as
prohibitions or use restrictions under
TSCA or the Federal Insecticide,
Fungicide, and Rodentkdde Act
(FIFRA), technology-based effluent
limitations for industrial dischargers
under the Clean Water Act, and a
National initiative to revise water
quality-based effluent limits in NPDES
permits. The remediation strategy
emphasizes appropriate control of
sources prior to remediation efforts
unless the contaminated sediments pose
a sufficiently great hazard to human or
environmental health to warrant
immediate remediation. Factors that
will be considered in implementing this
strategy include:
(1) Whether the sediment
contamination is contributing to severe
effects or substantial risks to aquatic
life, wildlife or human health;
(2) Whether continued delay in
removing the sediment would result in
the spread of harmful contamination
over a wider area or into important;
habitats;
(3) The likelihood of contaminated
sediments that are left in place at a
specific site to be transported to
downstream or offshore areas; .
(4) The timeframe for natural
recovery; the potential for contaminant
mobilization during remediation; and
(5) The feasibility and cost of various
treatment and removal options,
Cleanups of contaminated sediments
are occurring through the RAP process
and as a result of EPA's enforcement ,
program. Examples include fifty
thousand cubic yards of contaminated
sediment removed from the Black River,
Ohio, cleanup of one million pounds of
PCBs, initiated through a Superfund
enforcement action in Waukegan
Harbor, Illinois, and sediment cleanup
and environmental improvements.
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Federal Register / Vol. 58, No: 72 / Friday, April 16, 1^93 7 Prbjposed Rules
206219
provided for in a-$34 million settlement
in the Grand Calumet River, Indiana.
6. Atmospheric Deposition
Airborne deposition of pollutants is
believed to have a significant impact on
the water quality of the Great Lakes ,
, System. The "Great Lakes Water duality
Agreement provides that'the United
.States and Canada, in cooperation with
. the Great Lakes States and the Province
of Ontario, shall conduct research, ;
surveillance, and monitoring, and .
implement pollution control measures
for the purpose of reducing atmospheric
deposition of toxic substances,
particularly persistent toxic substances,
to the Great Lakes Basin Ecosystem '
(Annexes 11 and 15). To implement :
these provisions, the United States and
Canada established.an Integrated
Atmospheric Deposition Network as
part of the Great Lakes .International .
Surveillance Plan .to monitor .
atmospheric loadings of toxic --. ;
substance's to the Great Lakes System.
Implementation of the major
provisions of the Clean Air Act
Amendments of 1990 (CAAA) is an
integral part :of EPA's broader program
to protect and restore the Great Lakes. .
By November 15,1993, then eveiy two
years thereafter, EPA (in.cooperation','. •
with the Department of Commerce) is
required by section 112(m) of the CAAA
to report to Congress concerning the
results of the Great Lakes monitoring .
studies and describe any revisions to
Federal law necessary/to ensure
protection of human health and the '.
environment in.'the Great Lakes System.
The report will determine whether ,
provisions'of section 112 are adequate .
to prevent serious adverse effects to
public health and serious or widespread
environmental effects. Based on the
report, EPA is required by November 15,
1995, to promulgate further emission
standards or control measures if
necessary _to prevent such effects.
Section 112(m) also requires the
establishment of at least one master wet/
dry facility on each of the five Great
Lakes to monitor toxic deposition in wet
and dry conditions as part of the Great
Lakes Air Deposition (GLAD) and
International Air Deposition (IADN) :
networks. The GLAD network includes
22 satellite stations that monitor metals
and conventional pollutants. The
United States and Canadian
Implementation Plan for the IADN :
master stations was revised and
accelerated in order to meet the
deadlines imposed by the GAAA. Data
supplied by this effortwillbe used to
identify^and track movement of
hazardous air/pollutants; determine
loadings due to atmospheric deposition;
and support development of RAPs and ^
LaMPs. Other regulatory programs are
subject to the requirements of "
antidegradation if they have .
independent regulatory authority .
requiring compliance with water quality
standards. Section 112(m) of the Clean .
Air Act has such requirements. .
In accordance with section 182 of the
CAAA of 1990, States .with areas
designated non-attainment for ozone
must submit revisions to their
implementation plans providing for a 15
percent reduction in volatile.organic
compound (VOC) emissions, to be '
achieved by November 15,1996. As
many VOCs are also toxic air pollutants, '
the 15 percent VOC reduction will
include reductions in numerous air
toxics. Implementation of regulatory
programs^ that reduce the emissions of
VOGs and particulate matter will benefit
the water quality of the Great Lakes
System by decreasing atmospheric
deposition to the System.
In addition, between 1992 and 2000,
EPA must promulgate technology-based
emission standards for all source
categories of the 189 toxic air pollutants
listed hi section 112(b) of the CAAA. In
setting these standards, EPA will
consider inter-media transfer effects.
Such standards must be fully
implemented by November 15,2003, ;
and will apply to all major stationary
sources and some area sources of the
listed pollutants in the States adjacent
to the Great Lakes System, Under
section 112(f), these Standards will be
.followedbetween 2001 and 2008 by
risk-based standards, where necessary,
to ensure that public health is protected
with an ample margin of safety and to
ensure adverse environmental effects
are prevented subject to. cost, energy and
safety considerations. Under section
"112, EPA may add additional substances
to the list of toxic air pollutants
(including pollutants of concern in the
Great Lakes) when scientific
information dictates additions are
warranted. :
Title IV of the CAAA provides for a
reduction in SO2 from utilities of :
approximately 10 million tons by 2010,
Not only will a portion'of this reduction
occur in the Great Lakes, but many of
the control technologies permittees are
likely to use to achieve .these reductions
may reduce toxic air pollutants, such as
'mercury, that are specifically of concern .
in the Great Lakes System.
Finally, under T,itle n of the CAAA,
substantial nationwide reductions in
VOC emissions'from motor vehicles will
be achieved, including reductions in
toxic pollutants. Title n also requires.
EPA to conducta study of mobile Source
toxic emissions and promulgate '•-.'
regulations .to control air toxic
emissions from motor vehicles by May
15,1995. Such regulationSn by reducing
ah- toxics emissions nationwide will ,..'...
benefit the.water quality, of the Great
Lakes System by reducing loadings from
atmospheric deposition.,
7, Storm Water / - •
The 1987 amendments to the Clean
Water Act, section 402(p), required EPA
to establish a comprehensive, two-
phased approach for controlling storm
water discharges. In Phase L the CWA
required EPA to develop NPDES permit
application requirements for two major •
classes of dischargers: large (over
250,000 population served) and medium
(100,000-250,000 population served)
sized municipal separate storm sewer
systems; and storm water discharges :
"associated with industrial activity."
Congress also included two other
classes of storm water discharges in '
Phase I: discharges which had already
obtained a permit prior to February 4,
1987, and .discharges which EPA or a
NPDES State determines contribute to a
violation of-a water quality standard or
is a significant contributor of pollutants
to the waters of the United States. The
1987 Amendments, as further amended
by section 312 of the Water. Resources,
Development Act of 1992, prohibit EPA
and NPDES States from requiring "-'..;
permits for the remaining classes and
sources pf storm water discharges--
.(Phase ri) prior to October lj 1994.
The storm water permit application
Phase I regulations, promulgated on
•November 16,1990, established the
scope of the program. The rule "
identified 220 large and medium
municipal separate storm sewer systems
(173 cities and 47 counties) for
permitting, defined what constitutes a
storm water discharge "associated with
industrial activity," and established
specific permit application -.-',••
requirements and deadlines. Permit
application requirements for large and-
medium municipal separate storm
sewer systems require them to propose
storm water management programs to
control storm water discharges to the
"maximum extent practicable," and to
effectively prohibit non-storm water
discharges to the storm sewer system.
The 1990 .definition of storm water'
discharges "associated with industrial
activity" includes industrial facilities in
the Great Lakes System in such
industries as mining, manufacturing,
hazardous waste treatment, storage and
disposal facilities, landfills, power;
plants and transportation facilities. '--;•',
These facilities must comply with ....;•
individual or group NPpES permit"
application requirements,; or meet .
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
requirements specified in general
permits. The controls imposed on the
storm water discharges from these
facilities in individual or general
permits will significantly reduce the
loadings of pollutants to the Great Lakes
System.
8. Combined Sewer Overflows (CSOs)
EPA is currently improving and
accelerating implementation of the
National Combined Sewer Overflow
Control Strategy (54 FR 37370, Sept 8,
1989). As part of this effort, EPA issued
on January 19,1993, a draft policy that
more clearly defines EPA's
interpretation of,the appropriate
technology-based and water quality-
based requirements to be included in
NPDES permits to control these point
source discharges nationwide. See 58
FR 4994. Representatives of publicly
owned treatment works, States and
environmental groups participated in
developing the permitting component of
the draft policy, which also contains an
enforcement component. EPA expects to
issue the policy in final form during
1993. Additional ongoing efforts to
address CSOs in the Great Lakes System
and the application of the proposed
Guidance to those discharges are
discussed in section IUE,2!b.l of this
preamble.
9. Discharges of Oil and Hazardous
Polluting Substances
Annexes 4,5,6,8, and 9 of the Great
Lakes Water Quality Agreement address
the discharges of oil and hazardous
polluting substances into the Great
Lakes, including discharges of oil and
hazardous polluting substances from
vessels, discharges of vessel wastes,
pollution from shipping sources,
discharges from onsnore and offshore
facilities, and joint contingency plans.
EPA has initiated several programs
recently to address oil spill prevention
and control measures nationally and in
the Great Lakes System. For example,
EPA proposed a revised Spill
Prevention Control and
Counlermeasures (SPCC) regulation (40
CFRpart 112) in the Federal Register on
October 22,1991 (58 FR 54612). The
proposed rule is intended to clarify
existing regulatory language. EPA also
published a proposed rule in the
Federal Register on February 17,1993,
(58* FR 8824) addressing facility
response plans required under CVVA
section 311(j)(5), added by the Oil
Pollution Act of 1990. Further, EPA
targeted 182 SPCC inspections in the
Great Lakes System during fiscal year
1991 and completed 196.
Additionally, the Oil Pollution Act of
1990 strengthens United States
programs for preventing and responding
to spills. Research conducted under
Title VH of the OPA to assess the Oil
Pollution Act of 1990 strengthens
United States programs for preventing
and responding to spills. Research
conducted under Title VII of the OPA to
assess the status of navigation safety,
state-of-the-art pollution prevention
techniques, and development of
efficient oil spill response techniques
will benefit the Great Lakes System.
EPA and the Coast Guard have mapped
areas of the Great Lakes which may be
vulnerable to spills and are identifying
potential weaknesses in current
prevention and response programs.
JO. Nonpoint Sources of Pollution From
Land-Use Activities
Annex 13 of the Great Lakes Water
Quality Agreement addresses.programs
and measures for the abatement and
reduction of nonpoint sources of
pollution from land-use activities. The
annex addresses efforts to further reduce
nonpoint source contributions of
phosphorus, sediments, toxic
substances and microbiological
contaminants contained in drainage
from urban and rural land, including
waste disposal sites, in the Great Lakes
System.
Section 118(d){6) of the Clean Water
Act requires EPA in consultation with
the Great Lakes States to develop a five-
year plan and program to reduce
nutrient loadings to the Great Lakes.
EPA has implemented this requirement
within the existing water quality
management framework, including
through development of Phosphorus
Load Reduction Plans. Interagency task
forces in each of the Great Lakes States
have developed individual State
Phosphorus Load Reduction Plans to
achieve full compliance with point
source discharge limits and reduction of
agricultural phosphorus loads through
conservation tillage and better nutrient
management. Based on these plans, the
Phosphorus Load Reduction Task Force
has prepared load reduction plans
outlining State and Federal efforts
necessary to ensure that each State
meets its target load reduction.
In addition, the Coastal Zone Act
Reauthorization Amendments of 1990
(CZARA) make available to eligible
States funds for the development of
nonpoint control programs to restore
and protect coastal waters, such as the
Great Lakes. Under the CZARA,
Michigan, New York, Pennsylvania and
Wisconsin, as coastal States with
federally approved coastal management
programs, are required to develop
programs containing enforceable
policies and mechanisms in order to
ensure implementation of management
measures to address nonpoint pollution
from agricultural, urban and
silvicultural runoff and other sources.'
Participating States must submit their
programs to EPA and the National
Oceanic and Atmospheric
Administration for approval within two
and a half years of EPA's publication of
final guidance specifying nonpoint
source management measures. Final
guidance was published on January 19,
1993. See 58 FR 5182. States failing to
submit approvable programs will lose
grant funds that would otherwise be ..
awarded under section 319oftheCIean
Water Act and section 306 of the Coastal
Zone Management Act.
There is general agreement that
nonpoint sources of pollution (e.g., any
diffuse source of pollutant loadings to
• the waters of the Great Lakes System,
such as contaminated sediments, air
deposition, spills, etc., as well as ,
agricultural and urban runoff) are a
significant remaining cause of
environmentalrisk in the Great Lakes
Basin Ecosystem. In the December 16,
1992, report, "Evaluation of the
Guidance for the Great Lakes Water
Quality Initiative," the SAB endorsed
the broad based ecosystem approach of
the Initiative, but stated that it was not
clear what specific mechanisms the
Great Lakes Guidance had incorporated
to address pollution from these
nonpoint sources.
In addition to the ongoing State and
Federal programs described above, the
proposed Guidance affects nonpoint
sources in two ways. First, the water .
quality criteria and values in the
proposed Guidance apply to the
ambient waters of the Great Lakes
- System, regardless of the source of
pollutants to those waters. Although
criteria by themselves are not directly
enforceable under Federal law,
procedure 3 of appendix F (Total
Maximum Daily Loads) addresses
nonpoint sources by requiring allocation
of the available load capacity of the
receiving water among all sources of the
pollutant, including nonpoint sources.
Second, any regulatory programs
controlling nonpoint sources developed
by States or Tribes would also b& subject
to the antidegradation procedures in the
proposed Guidance.
Further, by establishing numeric
water quality criteria and values for the
protection of aquatic life, wildlife and
human health which apply to the- .-;
ambient.waters of the Great Lakes
System, regardless of the source of
pollutants to those waters, the proposed
Guidance provides the basis for
integrating actions carried out under the
range of environmental-programs
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-Federal Register /.Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
20831
available'to both Federal, State and ,
'Tribal regulators in order to protect and
restore the Great Lakes Basin Ecosystem.
In this manner, EPA believes the
proposed Guidance is consistent with
and furthers an ecosystem approach.
Additionally, as described in section
. E.G.12 below, EPA and the Gre.at Lakes
States have established a new program,
the Great Lakes Toxic Reduction
Initiative, to evaluate the development
of specific programs.and
implementation procedures to control
loadings of pollutants to the waters of
the Great Lakes System from nonpoint
: sources, Development of such programs
would further reduce pollutant loadings
to the waters of the Great Lakes System
and facilitate equitable division of the
costs of any necessary control measures
necessary to attain water quality
standards among point and nonpoint
sources. , - .
11. Great Lakes Fish Advisories
The Great Lakes States-currently have
issued 184 fish consumption advisories
that are currently in effect for various' -
waters of the Great Lakes System. In the
United States, the States have the
primary responsibility for advising the
/public of the risks associated with the
consumption of sport-caught fish; If a
potential local health threat exists, a
State rriay choose to issue warnings or
provide guidance on the quantity of
contaminated fish which may be
consumed. In recent years, while the
number of restrictions on eating Great
Lakes fish has declined, State officials
recommend the continued adherence to
guidelines for sport fish consumption.
The Great Lakes States are presently
reviewing and strengthening the "
procedures for issuance of fish
advisories in the Great Lakes System, •
particularly as they perjain to certain
more-affected segments of the -'.-.._'
population, such as subsistence and
sports fishers. This effort also includes
an evaluation of the issuance of joint
fish consumption advisories on multi-
jurisdictional lakes. A Fish Advisory
Task Force, composed of representatives.
from.each Great Lake State and EPA, is
currently developing a common fish
advisory protocol. This protocol will
consider the possible reproductive
impactsiand other relevant toxicological
endpoints associated with the
consumption of contaminated Great
Lakes fish. Such an approach, once
adopted and implemented, will provide
enhanced, consistent, risk-based
protection of human health.
12. Environmental Monitoring and Data
Management Programs for the Great
Lakes
EPA has established the
Environmental Monitoring and r'
Assessment Program (EMAP) to provide
a comprehensive program to monitor
the condition of the nation's ecological
resources. The Great Lakes are one of
seven basic resource groups included
within EMAP (EMAP-GL) which also
covers the coordination of
environmental indicators,.statistical
design and analyses, landscape
characterization, integration and
assessment, quality assurance,. •
information management, geographical
information services and logistics. The
data collected under EMAP-GL is ;
intended to describe current conditions
within the Great Lakes System, report
on ecological trends using a.set of
environmental indicators on a lakewide
scale or resolution and evaluate-long-
term changes in the condition of the
Great Lakes System as a result of
management and regulatory programs.
The Great Lakes National Program
Office is developing a comprehensive
data integration and management .
strategy for EPA's Great Lakes programs.
When implemented, the strategy will
support Federal, State and local efforts
to restore and maintain the chemical,
physical and biological integrity of the
waters of the Great Lakes Basin
Ecosystem. EEA expects the strategy to
be completed in 1993. .
13. Great Lakes Toxic Reductions
Initiative Multi-media Management •
Committee ' '
EPA believes an ecosystem approach
to addressing the environmental
problems of the Great Lakes defines the
" need to establish consistent, uniform
programs to reduce loadings of toxic
pollutants to the waters of the Great
Lakes System from all sources. This
ecosystem approach is reflected in the
Great Lakes Five Year Strategy
(discussed in section I.G.I), which
commits the States, .Tribes and Federal:
Agencies reap onsible for', environmental
protection and resource management in
the Great Lakes Basin to achieving
specific environmental goals.
Specifically, in the area of toxics ~
reductions, the Strategy calls for .
[reducing] the level of toxic substances
in the Great Lakes System with an
emphasis on persistent toxic substances,
so that all~organisms are adequately
protected and toxic substances are :
virtually eliminated from the Great
Lakes ecosystem. As discussed above, a
wide range of pollution control, "
abatement and prevention activities are
•_ currently underway throughout the
Great Lakes Basin, implementing,
numerous statutes and policies at the
Federal, State and local levels.
Further, EPA believes that the water
quality criteria, methodologies,
implementation procedures and '
antidegradation provisions in the " - •
proposed Guidance satisfy the
requirements of section, 118(c)(2) of the
CWA and will greatly advance the CWA
and GLWQA goals to restore and
maintain the integrity of the Great Lakes
System. EPA recognizes, however, that
full achievement of these goals depends
upon the successful implementation of
• a variety of media-specific programs. :
- Accordingly, EPA and the Great Lakes
States agreed to establish a multi-media
process through the "Great Lakes Toxics
Reduction Initiative" (GLTxRI) to :
identify and address any gaps or barriers
to establishing uniform consistent load
reduction programs for sources which
effect the Great Lakes Basin Ecosystem,-
including whether additional guidance'
. or policies should be developed for any
particular discharges of toxic pollutants -
of concern to the waters of the Great" • •"
Lakes System. A primary goal of the
GLTxRI is to establish a consistent,
uniform approach across all media to
reduce loadings of toxic pollutants to
the waters of the Great Lakes System,
and accelerating scheduled actions in
order to achieve necessary reductions.
The range of sources ortoxic :
' pollutants to be addressed under the
GLTxRI includes, but is not limited to-
agricultural nonpoint sources, wet-
weather point source discharges,
hazardous waste sites, air deposition,
contaminated sediments and spills due
to storage^ handling or transport
activities.,In conjunction with the' .. .-.
numeric-water quality criteria and
values, implementing procedures and
antidegradation policies established
through the final publication of the
Great Lakes Water Quality Guidance,
this process will provide EPA and the.
Great Lakes States and Tribes with a
comprehensive, integrated framework
for reducing toxic loadings to the waters
•of the Great Lakes System', with the goal
of virtually eliminating toxic pollutants;
Of specific concern to EPA and the
States is the reduction of those
pollutants classified as Bioaccumulative
Chemicals of Concern in the proposed
Guidance, as they pose the greatestrisk
to the Great Lakes Basin Ecosystem in
terms of systemwide impacts. Together,
these activities will enable EPA and the
Great Lakes States and Tribes to develop
cost-effective strategies to further the
goals and requirements of the CWA and
the GLWQA, and ensure attainment of
the water quality criteria and values
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20832 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
established through the publication of
the final Great Lakes Guidance.
One particular issue the GLTxRI
management committee will focus on is
the inter-media transfer of pollutants.
EPA and the Great Lakes States are
concerned that future reductions in
loadings of toxic pollutants to the water
may causa the transfer of pollutants
from one media to another—e.g., from
water to air—rather than overall
reductions in loadings to the
environment. As a result of this
concern, the GLTxRI management
committea will identify and evaluate
measures for minimizing inter-media
transfers. Possible measures for -
consideration include whether a
permittee shall be required to provide
information on how it will comply with
any more stringent limitations in a draft
permit, including information relevant
to the transfer of pollutants from one
medium to another, whether the
reduction would be attributable to
source reduction techniques, and
whether the facility has evaluated any
altemativa pollution prevention
measures.
The SAB in its December 16,1992,
report, Evaluation of the Guidance for
the Groat Lakes Water Quality Initiative,
recommended that EPA promote a
broadly based ecosystem approach
which considers not only point source
discharges but nonpoint sources,
sediments, atmospheric fall-out, and
groundwater as targets for conservation
and control of undesirable loadings.
EPA bolieves through implementing the
full rango of existing regulatory and
voluntary programs described above to
prevent pollutants from being
introduced, reduce pollutant loadings
currently being discharged, and
remediate the adverse effects associated
with past pollutant discharge to the
Great Lakes System, a comprehensive
ecosystem approach to protecting and
restoring the Great Lakes is being
actively pursued by EPA and the Great
Lakes States and Tribes. Further, EPA
believes the application of the numeric
water quality criteria and values
proposed hi the proposed Guidance to
the ambient waters of the Great Lakes
System, regardless of the source of
pollutants to those waters, is consistent
with and promotes the ecosystem
approach.
H. References .
Adler, A.C. et al. 1993. Reductive
' Dechlorination of Polychlorinated
Biphenyls in Anaerobic Sediments.
Environ. Sci. Technology 27(3):530-538.
Andre, A.W., D.N. Edgington, J. Manchester,
S. Murphy, D. Pham, M. Vogel, Z.
Matacz. 1993. Application of the Mass
Balance Approach to Green Bay:
Sediment Loading, Fluxes and
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Baker, J.E. and S.E. Eisenreich. 1989. PCBs
and PAHs as tracers of particulate
dynamics in large lakes. J. Great Lakes
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Ballschmitter, K., M. Zell, and Z. Freseniuz.
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Beltran, R.F. 1992. Green Bay/Fox River Mass
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Capel, P.D. and S.J. Eisenreich. 1985. PCBs in
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DeVault, D.S., W.A. Wilford, R.J. Hesselberg,
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Weishaar. 1988. Contaminants and
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Durham, R.W. and-B.G. Oliver. 1983. History
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Eisenreich, S.J. 1987. The chemical
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Eisenreich, S.J. et al. 1989. Environ. Sci. and
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1991. Toxic Chemicals in the Great Lakes
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Toronto, Burlington and Ottawa.
Great Lakes Science Advisory Board. 1990i
Final report of the ecosystem objectives
committee, March 1990. Windsor,
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Hermansori, M.H., E.R. Christensen, D.J.
Buser and L. Chen. 1991.
Polychlorinated biphenyls in dated
sediment cores from Green Bay and Lake
Michigan. J. Great Lakes Res. 17(1):94-
108.
International Joint Commission, Sediment
Subcommittee. 1988. Procedures for the
Assessment of Contaminated Sediment
Problems in the Great Lakes. *•
Jafvert, C7T. 1991. Polychlprinated biphenyls.
In Biological Remediation of
Contaminated Sediments, with Special'
Emphasis on the Great Lakes, Report of
a Workshop, July 17-19,1990, C.T.
Jafvert and J.E. Rogers, ed., U.S. EPA,
EPA/600/9-91/001.
Kubiak, T.J., H.J. Harris, L.M. Smith, T.R.
Schwartz, D.L. Stalling, J.A. Trick, L.
Sileo, D.E. Docherty and T.C. Erdman.
1989. Microcontaminants and
reproductive.impairment of the Forster's
tern on Green Bay, Lake Michigan—
1983. Arch. Environ. Contain. Toxicol.
18, 706-727.
Legault, J. and T.. Kuchenberg. 1978.
Reflections in a Tarnished Mirror: The
Use and Abuse of the Great Lakes.
Golden Glow Publishing, Sturgeon Bay,
WI.
Ludwig, J.P. and H. Kurita. 1988. Colonial ,
bird deformities—An effect of toxic
chemical residues in the Great Lakes? In
The Great Lakes: Living with. North.
America's Inland Waters, Proceedings of
a Symposium. D.H. Hickcox, ed.,
American Water Resources Association,
Bethesda, MD.
Mackay, D. 1989. Modeling the long-term
behavior of an organic contaminant in a
large lake; application to PCBs in Lake
Ontario. J. Great Lakes Res. 15(2):283-
' 297. _„
Peakall, D.B. 1988. Known effects of
pollutants on fish-eating birds in the
Great Lakes of North America, Chapter 4
pp. 39-54 in Toxic Contamination In
Large Lakes, Volume 1 Chronic Effects of
Toxic Contaminants in Large Lakes,
N.W. Schmidtke, ed. Lewis Publishers,
Chelsea, MI. .
Quinn, F.H. 1992. Hydraulic residence times
for the Laurentian Great Lakes, J. Great
• Lakes Res. 18(l):22-28.
Rathke.'D.E. and G. McRae. 1989.1987
Report on Great Lakes Water Quality,
Appendix B: Great Lakes Surveillance,
Volume IH. Report of the Great Lakes
Water Quality Board to the International
Joint Commission, Windsor, Ontario, pp.
6.1.1-6.1.36. ,
Richardson, W.,.D.Endicott, D. Patterson.
1993. Addendum to the Green Bay/Fox
River Management Summary Report.
U.S. EPA.
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Register / Vol. 58. No. 72, / Friday, April 16, ;1993 / Proposed Rules
20833
Spangler, G.R. 1988. Perspectives on the
influence of toxic substances on, fishery
productivity. Chapter 11 pp.193-207 in
Toxic Contamination in Large Lakes,
Volume IT, Impact of Toxic Contaminants
; on-Fisheries Management, N.W.
Sehmidtke, ed. Lewis Publishers,
Chelsea, MI. . ,
Strachan, W.M.J. and M.G. Henry, chrs. 1990.
Final report of the Ecosystem Objectives
Committee. Report to the Great Lakes
Science Advisory Board of the ~ :
: "International Joint Commission,
Windsor, Ontario, ,
U.S. EPA Great Lakes National Program :
Office. 1989. Green,Bay Mass Balance
Study Plan: A Strategy for Tracking
Toxics in the Bay~6f Green Bay, Lake,
-• • Michigan. ' , -
U.S. EPA. 1989. Cooperative agreement
between the U.S. Environmental
Protection Agency, Great Lakes National
..: - Program Office (GLNPO) and the U.S.
Fish and Wildlife Service, National
. Fisheries Research Center—Great Lakes
(NFRG-GL), July 13,1989. Example of
cooperative agreement specifying da'ta
Collection supporting, e.g., DeVault et al.,
. 1986; DeVault etal., 1988; DeVault,
1993a; DeVault 1993b.
U.S. EPA. 1993. Derivation of Proposed '
Human Health and Wildlife
Bioaccumulatibn Factors for the Graat
Lakes Initiative. NTIS Number; PB93- -
154672. JERIC Number: 3920.
Wiemeyer, S.N., T.G. Lamont, C.M. Bunck,
C.R. Sindelar, F.J. Gramlich, J.D. Fraser,
and M.A. Byrd. 1984. Organochlorine
pesticide, polychlorobiphenyl, and .- .
mercury residues in bald eagle eggs-^-
1969-79—and their relationships to
shell thinning and reproduction. Arch.
Environ. Contam. Toxicol. 13:529-549.
Willford, W.A., R.A. Bergstedt, W.H. Berlin,
N.R. Foster, R.J. Hesselberg, M.J. Mac,
D.R. M. Passmo, R.E. Remert and D.V.
; 'Rottiers. 1981. Chlorinated hydrocarbons
. as a factor hi the reproduction and ,
survival of lake trout (salvelinus .
namaycush) in Lake Michigan. Teclmical
Paper 105 of the U.S. Fish and Wildlife
Service, Great Lakes Fisheries
Laboratory, Ann Arbor, MI.
U.S. EPA. 1992. National Study of Chemical
Residues in Fish, EPA 823-R-92-008a.
II. Regulatory Requirements
The proposed Guidance consists of a
new part 132 of Title 40, Water Quality
Guidance for the Great Lakes System.
this section of the preamble describes
the overall regulatory requirements that
EPA proposes for adoption by the Great
Lakes States and Great Lakes Tribes.
A. Scope and Purpose -\', •• •
The Guidance consists of regulatory
requirements, contained in part 132,
. including six appendixes that provide
the text of the .Water Quality Guidance
that the Great Lakes States and Tribes
must adopt into their Jaws and
regulations. Part 132 as a whole
constitutes the Water Quality Guidance
for the Great Lakes System required by
section 118(c)(2) of the Clean Water Act
(Pub. L- 92-500 as amended by the
Great Lakes Critical Programs Act of
1990, Pub. L. 101-596).
Today's proposal also is intended to
satisfy the requirements of section
118(c)(7)(C) of the Clean Water Act that
EPA publish information concerning the
public health and environmental
consequenees of contaminants in Great
. Lakes sediment and that the information
include specific numerical limits to
protect health, aquatic life, and wildlife
from the bioaccumulation of toxins.
The Guidance has three major
purposes. First, it provides guidance to
the Great Lakes States and Tribes on
minimum water quality standards. To
accomplish this, the Guidance contains
numerical water quality criteria for 32 :
pollutants, listed iiLTables 1,2,3 and
4 in § 132.3. The Guidance also contains
methodologies for the development of
water quality criteria and water quality
, values for the protection of aquatic life,
human health, and wildlife, and a
methodology for development of
bioaccumulation factors, in appendixes
A, B, C and D. Together, these criteria
and methodologies specify numerical
' limits on pollutants in ambient Great
, Lakes waters to protect human health,
aquatic life, and wildlife.
. The second purpose of the proposed
Guidance is to provide guidance to the
Great Lakes States and Tribes on
antidegradation policies and to require
adoption of the Antidegradation
Standard, the Antidegradation
Implementation Procedures, the
Antidegradation Demonstration
provisions, and the Antidegradation
Decision provisions in appendix E.
The third purpose of the proposed
Guidance is to provide guidance on
implementation procedures, through the •
Water Quality Guidance
Implementation Procedures at § 132.5 '
and in appendix F. Some portions of the
Implementation Procedures also affect
, the adoption of minimum water quality .
standards. ,
B. Definitions . , • ''.-.. •
. Section 132.2 of theproposed .
Guidance contains definitions which
apply to this part. Section 132.2 is a .
partial list of terms which need to be -
defined for consistent interpretation of •
the Guidance in this part. Section:,
132.4(a) of the proposal requires Great
Lakes States and Tribes to adopt these
definitions as part of their water quality
standards or approved NPDES
programs. Other definitions, bearing on
the individual portions of the Guidance,
are contained in appendixes A through
F. Generally, where terms have been
applied in the Guidance in the same
manner as in previous National .
regulations, such as those in 40 CFR
122.2,130.2, and 131.3, a duplicate
definition has not been provided.
However, in some cases, duplicate
definitions have been provided to assist
the reader. The following paragraphs -
describe the origin of the terms defined
in§132.2.
The definition of "Great Lakes
System":is from section 118 of the Clean
Water Act (CWA) and the Great Lakes
Water Quality Agreement (GLWQA or
Agreement). It is providedfor the
convenience of the reader. Great Lakes'
States and Tribes must apply the .• '.
provisions of the Guidance to all
portions of the Great Lakes System
within their jurisdiction. Waters tif the
Great'Lakes System located within the
United States are "waters of the United
States" as defined in 40 CFR 122.2.
The terms "connecting channels of
the Great Lakes" and "Great Lakes" are
from section 118 of the Glean Water Act, _
The terms "load allocation," "loading
capacity," "total maximum daily-load"
and "wasteload allocation" are ,
duplicated from 40 CFR part 130, and
areincluded in this proposed Guidance
to assist the reader. EPA requests
• comments on the use of these
definitions in part 132. However, EPA is
not proposing today to revise 40 CFR
part 130, and is therefore not soliciting
comments on 40 CFR part 130.:^
The terms "existing uses," "Federal
Indian reservation" and "Indian Tribe"
are duplicated from 40 CFR 131.3, and
are included in this proposed Guidance
to assist the reader.
The terms "acute/chronic ratio,"
"acute toxic unit (TUa)," "chronic toxic
unit (TUc)," "EC50," and "no observed
effect concentration" are adapted from
the March 1991 EPA guidance
document, "Technical Support
Document for Water Quality-based
Toxics Control (TSD)." The TSD has
undergone extensive peer review, and
EPA.believes the technical definitions
derived from the TSD are valid
technically and scientifically. However,
there may be policy or administrative
implications" fromadopting; these
definitions in the proposed Guidance
that were not considered at the time the
TSD was developed. EPA invites
comment on the use of these definitions
in pairt-132. However, EPA is not
proposing today to revise the TSD, and
is therefore not soliciting comments on
the TSD in this proposed rulemaking.
The terms "open waters of the Great
Lakes" and "tributaries of the Great
Lakes System" were developed -- . -
primarily to facilitate application of
requirements that, for technical reasons,
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Federal Register / Vol. 58, No. 72 7 Friday, April 16, 1993 / Proposed Rules
have different application or effects
depending on the type of water body.
EPA invites comments on these
definitions.
The term "bioaccumulative chemical
of concern" is discussed in section n.G
of this preamble.
The term "wet weather point source"
is discussed in section II.E of this
preamble.
The term "Great Lakes States and
Groat Lakes Tribes" is defined in the
proposed Guidance to clarify which
States contain portions of the Great
Lakes System within their boundaries
(i.e., Illinois, Indiana, Ohio, Michigan,
Minnesota, New York, Pennsylvania,.
and Wisconsin). The proposal also
includes within the definition any
Indian Tribe as defined below whose
reservation lies in whole or in part
within the drainage basin of the Great
Lakes, and that EPA has determined
qualifies under section 518 of the Clean
Water Act to administer programs under
sections 303 (see 40 CFR 131.8) and/or
402 of the Clean Water Act.
The proposal includes Indian Tribes
in this definition because section 118(c)
requires the water quality guidance to
apply to the Great Lakes System, and
some portions of the Great Lakes System
are located within the boundaries of
Indian Reservations. Tribes are not
required to apply for authorization to
administer programs under sections 303
or 402 of the Clean Water Act, However,
if they do, they are required to adopt
requirements consistent with section
118 of the Clean Water Act and the final
Guidance adopted in part 132 in order
to control discharges into the Great
Lakes System to the same extent as
Great Lakes States. If they do not, EPA
or State water quality standards which
may apply to Indian Reservations must
incorporate the requirements of part
132, and EPA will incorporate the
requirements of this part into EPA-
issued permits for discharges on Indian
Reservations. For further discussion of
how the water quality standards
program operates on Indian
Reservations, see 54 FR 64891 Pec. 12,
1991).
EPA believes that inclusion of Indian
Tribes in the proposed Guidance is
consistent with section 518 of the Clean
Water Act While section 518(e) does
not explicitly address Tribal assumption,
of responsibilities under section
118(c){2), it does address water quality
standards and NPDES programs which
are the base programs addressed by the
section 118(c){2) requirements. Section
518 clearly allows Indian Tribes to be
authorized to administer both water
quality standards and NPDES programs,
and EPA sees no reason why Indian
Tribes should not be similarly treated
for purposes of section 118(c)(2).
Indeed, were EPA not to require that
Indian Tribes comply with the proposed
requirements in the proposed Guidance,
there could be a gap in the protection of
the Great Lakes System. EPA does not
believe that Congress would have
intended this result.
EPA invites comment on the
inclusion of Indian Tribes in this
definition, including the policy,
administrative and resource
implications of requiring Indian Tribes,
who are authorized to administer
programs under sections 303 and/or 402
to adopt the provisions of this
Guidance. At this time, there are no
Indian Tribes authorized to administer
programs under either section 303 or
section 402 within the boundaries of the
Great Lakes System. EPA intends to
work with the Great Lakes Indian Tribes
on a govemment-to-government basis to
provide them with a greater
understanding of the Great Lakes •
Guidance and its impact on Tribal
governments. To achieve this, EPA
plans to develop a specific outreach .
program with the Great Lakes Tribes
within the context of a broader public
forum to inform the public on the
elements of the Guidance.
The terms "carcinogen,"
"noncarcinogen," "quantitative
structure activity relationship," "slope
factor," "threshold effect," and
"uncertainty factors" are derived from
EPA's risk assessment methodologies,
and were adapted for application in this
Guidance. These terms and their usage
are discussed in sections V and VI of
this preamble.
The terms "compliance evaluation
level," "detection level," "minimum
level," and "quantification level" are „
discussed in section VHI.H of this
preamble. The term "detection level" is
from 40 CFR 136.2(f), and is provided
for the convenience of the reader.
The terms "acceptable daily
exposure," "acute toxicity," "adverse
effect," "bioaccumulation factor,"
1 'bioaccumulation,''' 'bioconcentration,''
"bioconcentration factor," .
"biomagnification," "chronic toxicity,"
"depuration," "LC50," "linear multi-
stage model," "lowest observed adverse
effect level," "no observed adverse
effect level," "octanol-water partition
coefficient," "relative source
contribution," "steady state BAF/BClV'
"superlipophilic chemical," and
"uptake" are derived from common
usage by toxicologists and biologists,
and were adapted for application in this
proposed Guidance. These terms are
discussed further in sections HI through
VI oaf this preamble, in appendixes A
through D, and in the corresponding
Technical Support Documents.
The term "threatened or endangered
species" is defined for the purposes of
the proposed Guidance as those species
that are listed as threatened or
endangered under the Federal
Endangered Species Act. This definition
is discussed in section ILK of this
preamble.
The terms "human cancer criterion,"
"human cancer value," "human
noncancer criterion," "human
noncancer value," and "risk associated
dose" are discussed in section V of this
preamble.-The selection of the one in
100,000 risk level for human cancer
criteria and values, and risk associated
dose, is also discussed further in section
V. •
The terms "criterion continuous
concentration," "criterion maximum
concentration," "final acute value,"
"final chronic value," "final plant
value," "genus mean acute value,"
"genus mean chronic value," "species
mean acute value," and "species mean
chronic value" were adapted from
EPA's "Guidelines for Deriving
Numerical National Water Quality
Criteria for the Protection of Aquatic
Organisms and Their Uses" (Stephan, et
al., 1985) for application in the
proposed Guidance." These terms are
explained more fully in appendix A of
the proposed Guidance and in section
III of this preamble.
The terms/'Tier I criteria" and "Tier
II values" are provided to differentiate
between products of Tier I
methodologies which either have been
adopted as numeric criteria into water
quality standards or are used to
implement narrative criteria ("Tier I
criteria"); and products of Tier II
methodologies which are used to
implement narrative water quality '
criteria ("Tier II values"). (Sections III, V
and VI of this preamble explain the use
of Tier I and n methodologies in this
proposed Guidance. EPA invites
comment on these definitions.
The terms "allowable dilution flow
(Qad)." "dilution fraction," and "stream
design flow" are discussed in section
VIII.C of this preamble.
EPA invites comment on all
definitions used in the proposed
Guidance. EPA also invites comments
on whether additional terms should be
defined in this part.
C. Adoption of Criteria, Methodologies,
and Procedures
Section 132.3 of the proposed
Guidance requires Great Lakes States
and Tribes to adopt numeric criteria for
16 pollutants for the protection of
aquatic life, listed in Tables 1 and 2;
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Federal Register /Vol. 58, No. 72 /Friday, April 16, 1993 /Proposed Rules
20835
numeric criteria for 20 pollutants for the
protection of human health, listed in
• Table 3; and numeric criteria for 4
pollutants for the protection of wildlife,
listed in Table 4. Section 132.4 of the ,
proposed Guidance requires Great Lakes
States and Tribes, to adopt the
. methodologies for developing numeric
,water quality criteria and values to
protect aquatic life, human health, and
wildlife specified in appendixes A
through D. Section 132.4 also requires
Great Lakes States and Tribes to adopt
the Antidegradation Policy in appendix
E and the Implementation Procedures in
appendix F. *
The Great Lakes Initiative Committees
developed the basis for the procedures
required in the proposed Guidance
because of a strong concern about the
environmental problems in the .Great
Lakes System and a concern that
differences in water quality standards,
antidegradation policies, and
implementation procedures were ;
leading to significant inconsistencies in
regulatory approaches between the
States. For example, human health
criteria for mercury range from 0.0069
ug/L in one Great Lakes State, to 2.0 ug/
L in another, with iio two States having
the same value. Similarly, aquatic Me
chronic criteria for cadmium range from
0.471 ug/L to 1.4 ug/L, and human.
. health criteria for benzene range from
0.7 ug/L to 710.0 ug/L, As another
example, only two States have
developed explicit water quality criteria
for the protection of wildlife. Further
examples of significant differences
between existing water quality programs
include: ;
1. The use by some States of
biqaccumulation factors when
calculating exposure, while other States
use the less restrictive bioconcentration
factors. These practices can lead to
differences of several orders of, -
magnitude in the stringency of water
quality-based controls.
2. The use of different "translator"
methodologies in developing derived
numeric criteria for implementing ,
narrative"water quality criteria.
3. The use of different assumptions
when calculating total maximum daily
loads and waste load allocations. For,
' example, different assumptions about
background concentrations, mixing
" zoiies.-receiving water flows, or
environmental fate can each ,
individually, result in orders of ,
magnitude differences in water quality-
based effluent limits in NPDES ;
discharge permits, ,
4. The use of different practices in
deciding what pollutants need to be
regulated in a discharge, what effect
dete'ction limits have on compliance
determinations, and how to develop
whole" effluent toxicity limitations.
For these reasons, the Steering -
Committee chose to develop guidance
on those aspects of current State water
quality standards programs and . •
implementation procedures which have
led to the most serious inconsistencies
among the Great Lakes States' water
quality programs, hi order to maximize
use of available time and resources, the
Steering Committee did not develop
guidance on areas that were currently
being addressed through other programs
or initiatives, or for implementation
procedures that relied primarily on best
professional judgment determinations of
permitting authorities. The Steering
Committee beh'eved that uniform
requirements were most necessary for
the criteria methodologies, anti- ,
degradation policies, and selected '
implementation procedures to ensure
consistent permit limitations for similar1
discharges throughout the Great Lakes
basin. The results of the Steering
Committee's work formed the basis for
EPA's development of the proposed
Guidance.
The areas not addressed in the '
proposed Guidance would continue to
he subject to all applicable Federal,
State, or Tribal requirements or
guidance. For example, the EPA
guidance document' 'Technical Support
Document for Water Quality-based :
Toxics Control" (March 1991)remains
fully applicable as evidence within the
Great Lakes System for topics that have
not been addressed by the proposed
Guidance, and fully applicable as
guidance for all topics for waters
outside the Great Lakes System.
D. Application of Methodologies,
Policies, and Procedures
1. The Two-Tiered Approach
The Initiative Committees were
concerned that traditional criteria
development methodologies would hot,
be adequate to address the wide range
of pollutants in the Great Lakes System.
In particular, in order to assure the
scientific validity of criteria as
protective of designated uses, criteria
methodologies include minimum •
requirements for lexicological data that:
may be difficult to meet except for a
limited number of well-studied
pollutants. In many cases, the full
complement of toxicity data is not
"available for a particular pollutant
which is nevertheless known or
expected to cause adverse effects to
humans, aquatic life, and wildlife.. Some,
of the Great Lakes States currently have
procedures that are intended for use as
translator mechanisms to derive ''.,
numeric ambient pollutant :
concentrations that will implement, in
conjunction with the proposed whole
effluent toxicity requirements, the
States' narrative criteria (e.g., "no toxic
substances in toxic amounts"),,The
Initiative Committees wanted to ensure
consistency among States in the Great -
.Lakes System as to how limited data are
used to derive values for regulating • -
discharges. The Initiative Committees
also wanted to develop a methodology
to be used as a translator mechanism
common to all Great Lakes States that
could be used in setting permit limits
for the Great Lakes System.
To address these needsrthe
Committees developed a two-tiered
approach, including:
_ a. Traditional criteria development
methodologies, to enable development
of water quality criteria (Tier I); and.
b. Methodologies under which water •
quality values (Tier n) could be
calculated with fewer data than the full
minimum data required for a Tier I
criterion calculation. The purpose of
Tier n methodologies is to provide Great
Lakes States with guidance on •
evaluating pollutants when there is '.. .
insufficient data to develop Tier I
criteria. ••;
The Initiative Committees intended
that the outcome of a Tier H analysis
would be a somewhat conservative
value to reflect the increased
uncertainty surrounding a more limited
database. For example, for aquatic life
criteria, this consideration resulted in
the development of a methodology
which generally produces more
stringent (lower) values where there are
fewer data, and less stringent values as
the database" increases.
EPA believes'that a uniform method
will advance the goals of the Great
Lakes Critical Programs Act (CPA). First,
EPA believes that the additional
protection that the Tier n approach will
provide is consistent with the objectives
of the Great Lakes Water Quality
Agreement, as incorporated into section
118 of the Clean Water Act. Article H of
the GLWQA provides that the United
States and Canada will make maximum
efforts to develop programs, practices
and technology necessary for a better
understanding of the Great Lakes
System, and to eliminate or reduce to
the maximum extent practicable the
discharge of pollutants into Great Lakes
waters. Article HI provides general
narrative objectives for the Great Lakes
System including that the Great Lakes
waters should be iree from deleterious
substances including p ollutants that are;
toxic or harmful to humans, animals of
aquatic life. The conservative Tier It' •'.''.
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
method proposed will contribute to the
more rapid achievement of these goals.
Additionally, EPA believes that the
Tier n approach is consistent with
Congress goals and objectives. The
legislative nistory of the CPA indicates
that Congress recognized that the Great
Lakes is both a unique, interconnected
ecosystem and a unique National
resource that might require unusual
measures to protect. See, for example,
136 Cong. Rec. S. 15622-23, Oct. 17,
19SO (Son. Kohl); S. Rep. No. 101-339,.
101st Cong., 2d Sess. at 7. EPA believes
that Congress gave EPA discretion to
regulate the Great Lakes waters more
stringently than other waters of the
United States, where a more stringent
approach would promote more rapid
achievement of desired water quality
across the Great Lakes basin.
Consequently, EPA is proposing Tier n-
methods for aquatic life, human health,
and wildlife protection that the
Initiative Committees developed.
Sections D.2 and D.3 below describe the
two-tiered approach in more detail.
2, Application of Tier I Methodologies
The proposed Guidance requires
Great Lakes States or Tribes to use the
Tier I methodologies in appendixes A
through D when adopting or revising
numeric water quality criteria. In
addition, if a Great Lakes State or Tribe
has not adopted a numeric water quality
criterion for a pollutant in its water
quality standards, but enough data
exists to meet Tier I minimum data
requirements, § 132.4(c) requires use of
the Tier I methodologies for any
development of numerical criteria to
implement narrative criteria. As
discussed further below, such
implementation would include
development of water quality-based
effluent limits, where appropriate.
This approach is less flexible than
currently allowed under 40 CFR part
131, where States may use EPA's section
304(a) methodologies, or any other
scientifically defensible method, in
developing numeric criteria and
implementing narrative criteria. EPA
believes that the proposed approach is
desirable and consistent with
Congressional intent in order to achieve
a greater degree of consistency of water
quality-based controls within the Great
Lakes System.
The proposed Guidance also includes
proposed numeric criteria in Tables 1
through 4 of part 132 that were derived
using the Tier I methodologies. EPA is
proposing to require Great Lakes States
and Tribes to adopt these specific
numeric criteria into their water quality
standards for the Great Lakes System.
Over time, a database from which
both numeric Tier I water quality
criteria and Tier n water quality values
can be derived will expand. EPA Region
5, in cooperation with Regions 2 and 3,
Headquarters offices, and the Great
Lakes States and Tribes, will establish a
clearinghouse for these environmental
data. As additional data become
available or additional Tier I numeric
criteria and Tier II values are calculated
by EPA, States, or Tribes, Region 5 will
ensure that this information is
disseminated to the Great Lakes States
and Tribes. Regions 2, 3 and 5, through
their review and approval of State water
quality standards under section 303 of
the Clean Water Act, will ensure that
the Great Lakes States and Tribes
maintain the minimum consistent level
of protection for aquatic life, human
health, and wildlife throughout the
Great Lakes System provided by
application of the methodologies
promulgated in the final Guidance. ,
The proposed rule does not alter
existing regulations under 40 .CFR part
131 concerning when a State is
obligated to adopt a numeric water
quality criterion beyond those specified
in Tables 1 through 4 of the proposed
Guidance. Section 303(c)(2)(B) currently
requires States to adopt numeric criteria
for toxic pollutants for which section
304(a) criteria are available, and which
could reasonably be expected to
interfere with designated uses. EPA
regulations do not specify other
instances where numeric criteria are
required, though EPA has the authority
to identify such instances on a case-by-
case basis under section 303(c)(4) of the
Clean Water Act.
One alternative to the proposed
Guidance would be to broaden the
States' and Tribes' obligation to adopt
numeric Tier I criteria into water quality
standards. Specifically, EPA could
instead require the Great Lakes States
and Tribes to adopt a Tier I criterion
into their water quality standards when
sufficient toxicological data exists under
a Tier I methodology, and when the
pollutant could reasonably be expected
to interfere with the designated uses in
ambient waters, for all pollutants •
including pollutants for which EPA had
not developed National criteria under.
section 304(a). EPA decided-not to
propose this alternative, however,
because it may increase the
administrative burden on Federal, State
and Tribal authorities without
necessarily providing a significant
advantage over EPA's periodic review of
State or Tribal water quality standards
to determine the need for numeric water
quality criteria. Another alternative
would be for EPA to amend Tables 1
through 4 in future rulemaking to
include additional Tier I criteria as
sufficient data become available or are
evaluated, and require the Great Lakes
States and Tribes to adopt these criteria
into their water quality standards. EPA
Jnvites comment on these or other
alternatives to the proposed Guidance,
including the advantages and
disadvantages of requiring Great Lakes
States and Tribes to adopt any Tier I
criterion subsequently calculated or
approved by EPA into their water
quality standards for the Great Lakes
System.
Section 132.4(c) also requires the use
of Tier I methodologies when
developing numeric criteria to
implement State or Tribal narrative
criteria if data satisfying the Tier I
minimum data requirements are
available. For example, if a State or
Tribe is deriving numeric criteria for a
pollutant to implement the narrative
criteria and data are available that meet
the minimum data requirements for Tier
I, then the State or Tribe must use the
Tier I methodologies in the proposed
Guidance in deriving the numeric
criteria. In this example, because the
State or Tribe is not proposing to adopt
the numeric Tier I criteria into water
quality standards, the State or Tribe
does not need to submit the derived
numeric criteria to EPA for approval.
Instead, the State would use the derived
numeric Tier I criteria in developing
Total Maximum Daily Loads (TMDLs)
and water quality-based effluent limits.
In the context of EPA's review and
approval of the'resulting TMDLs under
40 CFR part 130, and review of the
water quality-based effluent limits in
NPDES permits submitted under part
123, EPA will review the State and
Tribal interpretations of narrative'water
quality criteria,
EPA invites comments on this
approach for the use of Tier I
methodologies required under'§ 132.4(c)
and any alternative approaches.
. 3. Application of Tier II Methodologies
It is preferable, in all cases, to have
Tier I criteria available to compute
water quality-based effluent limits.
However, the development of Tier I
criteria is often costly and time
consuming. In the absence of a Tier I
criterion, the permitting authorities
must have some mechanism with which
to interpret and ensure that the narrative
prohibition against the discharge of
toxic substances in toxic amounts is
reflected in water quality-based effluent
limitations. Options that EPA and the
Initiative Committees considered
include: a "no data-no discharge"
requirement, unless and until Tier I
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£0837
criteria are established; aft ad hoc
•interpretation of narrative criteria on a
case-by-case basis; of a systeiriatic .
methodology for deriving numbers in
the.absence of a full database. The ,
Initiative Committees have proposed the
latter option—to" propose, the use of a
Tier H methodology to derive values in ,
the absence of data sufficient to develop
.Tier I. criteria. EPA invites comment on
this approach, and on the other three
options described in this paragraph.
The Tier n approach sometimes
; requires additional conservatisms,.e.g.,
in the derivation of aquatic life criteria,
when the minimum data requirements :
for Tier I are not met. The approach may
therefore result in permit limits which
may later be found to be nonresistant
than those derived from new toxicity
data. In these cases, the cost of
cohiplying with the more stringent •
permit limits may be high because of the
additional conservatisms, while the
benefits may be low. Of course, one .
advantage of the Tier ri approach is that.
it ensures that even discharges of'.. ,
pollutants with insufficient data to
derive Tier I criteria pose low risks to
the environment. EPA solicits
comments on identification of any less
costly approaches to regulate .pollutants
for which inadequate data exist to
derive Tier I criteria that would fully
protect human health, wildlife, and
aquatic life in the Great Lakes System.
If a State of Tribe has not adopted a
numeric water quality criterion for a
pollutant and insufficient data exist to ••' .
meet Tier I minimum data requirements,
proposed § 132.4(c) requires application
of Tier II methodologies to develop Tier
n values to implement the narrative .'•
criteria. Additionally, if sufficient data
to calculate a Tier H value for a
.pollutant on Table 6 of part 132 does
not exist, procedure 5 of the
Implementation Procedures (appendix F
to part 132) requires the permitting
authority under specified circumstances
to generate or require the permittee to
generate the data necessary to derive
Tier n values. The requirements in
procedure 5 are discussed further in
section VIII.E of this preamble. :
As described aboyej the Tier n >..-.'•:
methodologies generally yield more
conservative numbers than Tier I, to
reflect the greater uncertainty related to
the absence of c.omplete data sets. This
creates an incentive on the part of
dischargers to generate additional
toxicological data. The proposed
Guidance recognizes this possibility,
and allows dischargers to provide such >
data. As described in section VOT-Ipf
this preamble, the proposed Guidance '
provides a reasonable period of time up
to two years to provide additional
studies necessary to develop a tier I
criterion or to modify :a Tier n value.
Permittee data jnustmeet the minimum:
data requirements in the proposed _"
Guidance; including quality assurance
requirements. Furthermore, the data are
subject to review by the permitting
agency. : |-
EPA invites comment on all aspects of.
this provision;including the two-tiered
approach for criteria derivation and the
use of the specified Tier II ,
methodologies, ' ~ .
In its December 16,1992, report,
"Evaluation of the. Guidance for .the
Great Lakes Water Quality Initiative,"
EPA*s Science Advisory Board (SAB)
expressed concern that anti-backsliding
provisions of the Glean Water Act may
prevent adjustments in Tier n numbers
when more data become available. EPA
belieyes that in most cases the anti-
backsliding provisions of the Glean
Water Act will not prevent adjustments
to either Tier Devalues or Tier I criteria.
First, under the proposed Guidance :
anti-backslidinp requirements do not
apply to changes made in an effluent
h'mitation prior to its compliance date.
(See proposed procedure 9, Compliance
Schedules, in appendix F to part 132.) '
Second, everi if anti-backslidiiig
requirements do apply, they may not bar
such adjustments. Under section 402(o) .
of the CWA, relaxation of water quality-
based limits is, permissible if either the,
requirements of section 402(6)(2) or
section 303(d)(4) are met. These two
provisions .are independent exceptions
to the prohibition against relaxation of
permit limits. The exceptions, under
section 3Q3(d)(4) will, in most cases,
provide the 'flexibility needed for
permitting authorities to issue permits
reflecting adjustments in Tier I or n
numbers. Section 303(d)(4)(A) allows
establishment of less stringent water .
quality-based effluent limits in a permit
for discharge into a non-attained water
if the existing permit limit was based on
a total maximum daily load or other
wasteload allocation established under
section 303, and attainment of water
quality standards is assured. Section
303(d)(4)(B) allows establishment of less
stringent water quality-based" effluent
limits in a pernjit for discharge .into an
attained water so long as the revised
permit limit is consistent with' a State's
antidegradation'policy, and continues to
assure compliance with applicable
water quality standards. EPA believes ;
that in most cases where Tier I criteria
or Tier II values change as a result of
additional data becoming available,
discharges will be able to meet the
conditions of section, 303(d)(4) and
therefore not be subject to the
prohibition contained in the Clean :
WaterAct. : ;
EPA invites comment on all aspects of
the above concerns about the two-tiered
approach being proposed, including
whether anti-backsliding,
antidegradation, or any other provisions
. or practices may be a significant
impediment to adjusting water quality
criteria arid values when additional data
become available, and what alternatives
may be available to address the ,
concerns.-
E. Applicability of the Water Quality
Guidance, . • ••
'. This section of the preamble discusses
in more detail the applicability of the
three major portions, of the proposed-
Guidance. , •
1. .Criteria and Values •'-';•
a. Background. Section 30,3(c) of the
Clean Water Act and implementing
regulations at 40 CFR part 131 specify
the manner in which EPA and the States
or Tribes must review; revise, and adopt
waiter quality standards. Water quality
standards include a designated use or
uses for the waters of the United States
and water quality criteria for such
waters based upon the designated uses.
In designating uses for a water body, '•'. '
States or Tribes must take into
consideration the use and value of water
for public/water supplies, protection
and propagation of fish, shellfish and
wildlife, recreation in and on the water,
agricultural, industrial, and other
purposes including navigatipn. Section
303(c)(2)(A) of the Clean Water Act; 40
GFR 131.10(a). States or Tribes may
designate uses not identified in section
303(c)(2)(A) of the Clean Water Act and
40 CFR 131.10(a) or specify
subcategories of uses for particular
water bodies, with the exception that no
State may designate waste transport or
waste assimilation as a use. 40 CFR
131.10(c). Finally, pursuant to section
510 of the Clean Water Act, States or
Tribes may designate-uses for particular,
water bodies which require application
of more stringent water quality criteria
than may be required under the Clean.
Water Act. In designating uses and
establishing appropriate criteria to
protect those uses, the States, or Tribes
must ensure the attainment and
maintenance of all downstream water
quality standards.
EPA's existing regulations at 40 CFR
131.10(g) authorize States or Tribes to
remove certain designated uses of a
water body (arid establish ;
correspondingly less stringent water
quality criteria) upon a demonstration
through a use attainability analysis as
described m 40 CFR 131.3(g)i that
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
attaining the designated use is not
foasiblebecause:
(1) Naturally occurring pollutant
concentrations prevent the attainment of the
use;
(2) Natural, ephemeral. Intermittent or low
flow conditions oc water levels prevent the
attainment of tha uso, unless these conditions
may be compensated for by the discharge of
sufficient volume of effluent discharges
without violating State water conservation
requirements to enable uses to be met;
(3) Human caused conditions or sources of
pollution prevent the attainment of the use
and cannot be remedied or would cause more
environmental damage to correct than to
leave in place;
(4) Dams, diversions oc other types of
hydrologic modifications preclude the
attainment of the use, and it is not feasible
to restore the water body to its original
condition or to operate such modification in
• way that would result in the attainment of
tha us®;
(5) Physical conditions related to the
natural features of ths water body, such as
the lack of a proper substrate, cover, flow,
depth, pools, riffles, and the like, unrelated
to water quality, preclude attainment of
aquatic lift protection uses; oc
(6) Controls more stringent than those
required by sections 301(b) and 306 of the
Clean Water Act would result hi substantial
and widespread economic impact
Under 40 CFR 131.10(h), however.
States or Tribes may not remove
designated uses if:
(!) They are existing uses, as defined in
§ 131.3, unless a use requiring more stringent
criteria is added; or
(2) Such uses will be attained by
Implementing effluent limits required under
sections 301(b) and 306 of the Clean Water
Act and by implementing cost-effective and
reasonable best management practices for
nonpoint source control.
In addition to modifying designated
usos for a particular water body, States
or Tribes may currently grant temporary
variances from water quality standards
to point sources based upon any of the
six grounds for removing a designated
usa set forth at 40 CFR 131.aO(g). EPA's
National policy on variances and the
proposed variance procedure for the
Great Lakes System are discussed in
section Vm.B, below.
b. Applicability of the Proposed
Guidance, Section 132.4(d) of the
proposed Guidance generally requires
Great Lakes States or Tribes to apply
criteria and values derived from the Tier
I and Tier II methodologies for human
health, wildlife, and acute and chronic
aquatic life to protect all waters of the
Great Lakes System. The proposed
Guidance does not affect the Great Lakes
States' or tribes' authority under 40
CFR 131.10 to retain, designate or
remove uses for portions of the Great
Lakes System entirely within their
jurisdiction. However, the proposed ,
Guidance differs from current National
requirements by generally requiring
State and Tribal application of the
criteria, values and methodologies in
titie proposed Guidance to all waters of
the Great Lakes System regardless of
existing State or Tribal use designations.
There are four exceptions to this
general requirement. First, pursuant to
section 510 of the Clean Water Act,
Great Lakes States or Tribes may apply
more stringent numeric criteria or
values to any waters of the Great Lakes
System within their borders. Second,
Great Lakes States or Tribes may
develop less stringent site-specific
modifications to the criteria and values
for aquatic life for specific waters of the
Great Lakes System in certain limited
circumstances. However, any such site-
specific modifications must still be
protective of aquatic life. This provision
is discussed in section VTTI.A, below.
Third, with regard to human health,
the methodology in appendix C
produces criteria and values under two
sets of exposure assumptions. The .
methodologies for deriving
"Nondrinking" criteria and values
assume that humans are exposed to
pollutants in the Great Lakes System via
two routes: incidental consumption of .
water as a result of recreational
activities in the Great Lakes System; and
consumption of fish that have
accumulated pollutants in their tissue.
The methodologies for deriving
"Drinking'' criteria and values assume
that, in addition to these two exposure
routes, humans are also exposed to
pollutants from the Great Lakes System
as a result of direct use of the waters
without treatment for drinking water
purposes. The "Drinking" criteria and
values are generally more stringent than
the "Nondrinking" criteria and values,
because of the additional route of
exposure. Section 132.4(d)(3) of the
proposed Guidance specifically
provides that the criteria and values
derived using the "Drinking"
assumptions shall apply to the open
waters of the Great Lakes, all connecting
channels of the Great Lakes, and all
other waters of the Great Lakes System
that have been designated for use as
public water supplies by any Great
Lakes State or Tribe in accordance with
40 GFR 131.10(a). Criteria and values
derived using the "Nondrinking"
assumptions are proposed to apply to all
other waters of the Great Lakes System.
Fourth, § l"32.4(g) provides that Great
Lakes States and Tribes are not required
to use the proposed criteria
development methodologies or
implementation procedures for
pollutants listed in Table 5 of the
proposed Guidance, or upon
demonstration that application of one or
more methodologies or procedures to
the pollutant is not scientifically
defensible. The rationale for these
exclusions is discussed in section II.F of
this preamble. . • ' "
Finally, upon incorporation into
enforceable State; Tribal, or Federal ,
laws, the criteria and values or:
appropriate site-specific modifications
developed under the proposed
Guidance will apply to a wide range of
regulatory decisions, including
decisions under statutes other than the
Clean Water Act. Examples of such
application include:
i. Issuance of NPDES permits
pursuant to section 402 of the Clean
Water Act or consistent provisions of
State law; ,
, ii. Issuance of permits authorizing the
discharge of dredged and fill material
pursuant to section 404 of the Clean
Water Act or consistent provisions of
State law;
iii. Development of Lakewide
Management Plans and Remedial Action
Plans pursuant to section 118(c)(4) of
the Clean Water Act, as amended by the
Great Lakes Critical Programs Act of
1990;
iv. Promulgation of emission
standards and control measures
necessary to prevent widespread
environmental or serious adverse public
health effects from atmospheric
deposition of air pollutants to the Great
Lakes pursuant to section 112(m) of the ,
Clean Air Act, as amended by the Clean
Air Act Amendments of 1990;
v. Determination of applicable or
relevant and appropriate requirements
(ARARs) under section 121 of the
Comprehensive Environmental
Response, Compensation" and Liability
Act of 1980; and
vi. Determination of corrective action
requirements under sections 3004(u),
3008(h), or 7003 of the Solid Waste
Disposal Act or consistent provisions.of
State law.
c. Justification for the Proposed
Approach. The requirement set forth in
the proposed Guidance that the criteria
and values generally apply throughout
the Great Lakes System regardless of use
designations is more restrictive than
current National policy. EPA believes
that this more restrictive approach is
necessary for the Great Lakes System for
several reasons.
First, as explained in section I above,
EPA believes that the Great Lakes are an
integrated ecosystem requiring a
consistent approach to pollution control
across the entire basin. Allowing Great
Lakes, States and Tribes to retain the
broad discretion that they possess under
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20839
the current National program would
seriously hinder—-and perhaps .
prevent—the attainment of the gqaJs of
the Great Lakes Critical Programs Act
amendments to section 118 of the Clean
Water Act. ; •
, • One of the most important goals of
this legislation was the establishment of
more uniform control of pollution
throughout the Great Lakes System. This
theme appears in hoth the House "and
Senate Committee reports-. See H.R. -
.101-704,101st Cong., 2d Sess. at 8
(Sept. 14,1990); S. 101-339,101st Cong.
2d Sess. at 12,18 (June 27,1990). It is
also a common thread in the floor • ;
statements of nearly all of the individual
members of Congress that addressed the
. House and Senate bills. See, e.g., 136
Cong. Rec. H 7918 (Sept. 24,1990}
(remarks of Rep. Roth); 136 Cong. Rec.
H12325 (Oct. 27,1990) (remarks of Rep.
Stangeland); 135 Cong. Rec. S 1153
(Sept. 20,1989) (remarks of Sen. Levin);
136 Cong. Rec. S 15620,15623 (Oct. 17,
1990) (remarks of Sen. Levin and Sen.
Kohl). The proposed Guidance, by
generally requiring application of the
criteria and values derived from the Tier
I and Tier II methodologies for human
health, wildlife, and acute and chronic
aquatic life to all waters of the Great
Lakes System (unless a State or Tribe
successfully shows the need for a site-
specific modification to the aquatic life
criteria and values) will promote this
goal.
Further, the legislative history shows
that Congress was aware of the Great '
Lakes States' Water Quality Initiative
and viewed this effort with approval.
See S. Rep. 101-339,101st Cong., 2d
Sess. at 18 (June 27,1990); 136 Cong.
Rec. S 15620 (Oct. 17,1990} (remarks of
Sen. Levin). Because the achievement of
consistent water quality was the key •
goal of the Initiative, it is reasonable to i
assume that Congress endorsed the same
goal.
•Third, a primary impetus behind the
initial creation of the Great Lakes Water.
Quality Initiative was the 1986 Great
Lakes Toxic Substances Control
Agreement ("Governors' Agreement").
In that Agreement, the Governors of the
eight Great Lakes States "commit[ted] to
managing the Great Lakes as an
integrated ecosystem, recognizing that
the water resources of the Basin
transcend political boundaries." The
Governors' Agreement explained that
such an ecosystem-based approach is
necessary because:
[t]he relatively closed nature of the system
makes the Great Lakes especially vulnerable
to pollution. Consequently, the actions of one
t jurisdiction or user in the system may have
' an impact on others. Because of this .
interdependence and the resource's :
economic and social value to the region, it is
crucial that the lakes be managed as an
integrated system. • • , •
The Governors'Agreement also
recognized that uniform water quality
standards .should be. developed for
pollutants of concern Jn the Great Lakes
System to avoid "costly duplication of
research and standardsetting." Finally, .';
the Governors' Agreement recognized -
that "[maintaining and improving the .
quality of Great Lakes waters will
sustain water supply systems and
commercial, manufacturing and ,
recreation industries, while creating
new economic development
opportunities." ; .
Section 13.2.4(d) of the proposed
Guidance implements the principles of
the Governors' Agreement and reflects
the proposal of the Great Lakes Steering
Committee to require the> Great Lakes
States to generally apply numeric :;
criteria and values equal to or more
• stringent ihan the Tier I criteria and Tier
II values throughout the Great Lakes
System, with the limited site-specific
exceptions discussed in section VULA,
below. This requirement is intended to
result in the development of more
uniform:water quality standards
throughout the Great Lakes System and
a reduction in costly duplication of •
research and standard-setting by the .-••
Great Lakes States and Tribes, .
Finally, the legislative history also
shows strong Congressional intent to
implement portions of the 1978 Great •
Lakes Water Quality Agreement relating
to water quality standards,
antidegradation policies, and
implementation procedures. See, e.g.,.
H.R. Rep. 101-704,101st Cong., 2d Sess.
at 2, 8 (Sept.14,1990); 136 Cong. Rec.'
H 7916 (Sept. 24,1990) (remarks of Rep.
Nowak); 136 Cong. Rec. S 15620,15623
(Oct. 17,1990) (remarks of Sen. Levin
and Sen. Kohl). Moreover, Congress :
interpreted the Agreement as requiring
uniform water quality "throughout the
GreatLakes." 136 Cong. Ree. S 15620
(Oct. 17,1990) (remarks of Sen. Levin).
The rationale for the human health'
methodology deserves additional'
discussion. The methodologies for
deriving '"Nondrinking" criteria and
values assume that humans are exposed
to pollutants in the Great Lakes System
via two routes: incidental consumption
of water as a result of recreational. »
activities in the Great Lakes System; and
consumption of fish that have
accumulated pollutants in their tissue. .
The methodologies for deriving
"Drinking" criteria and values assume
thati in addition to these two exposure
routes, humans are also exposed to
pollutants from :the Great'Lakes System
as a result of direct use of the waters :
without treatment for drinking water
purposes. Because of this additional
. route of exposure, the "Drinking"
criteria and values generally will be ,
. more stringent than those for ; : •
"Nondrinking."
Th"e requirement in §132.4(d)(3)(ii) of
the proposed Guidance regarding the
applicability of the "Nondrinking" ,
criteria and values is based upon two
conservative assumptions. First, EPA is"-'
assuming that humans use all waters of
the Great Lakes System for recreational
purposes, regardless of any applicable
use designations. Second, FJ?A is
assuming that humans consume .aquatic
life that swim through or live in (and
therefore have accumulated pollutants
from) all waters of the Great Lakes
System. Consequently, EPA is assuming
that humans may be .exposed to, -":-
pollutants from any water.of the Great •
Lakes System via either of the first two
routes of exposure described above. To
the extent that these assumptions are
inaccurate,: they err on the side of being
overprotective of human health rather ,
than underprotective. Moreover, this
approach will promote consistent
'• application of criteria and values ..-,--.
throughout the Great Lakes System,
thereby furthering one of the primary .
goals of the Great Lakes Critical ..;
Programs Act. Finally, this approach is
consistent with the proposal of the.
Steering Committee.:EPA requests
public comment on these assumptions.
, Sectionr132.4(d)(3)(i) of the proposed
Guidance requires application of the
."Drinking" criteria and Values to open
waters of the Great Lakes, the
connecting channels, and all other •
waters designated for use as public
water supplies. During the Great Lakes
Water Quality Initiative process, it was
suggested that because it is unlikely that
drinking water intakes will be located
behind constructed breakwalls, there is
no need to apply the "Drinking" criteria
and values to. waters that are located
behind constructed breakwalls. The
proposed Guidance does not allow this
exception for two reasons.
First, 40 CFR 131.11(a) requires that
"States must adopt those water quality
criteria that protect the designated use."
The "Drinking" criteria and values are
designed to protect humans from
suffering adverse health effects from.
drinking water; that is, they aje ,
designed to protect public water supply
uses. All of the open waters of the Great
Lakes have been designated for public
water supply uses. The proposed
exception for waters located behind
constructed breakwalls, to the extent it
would allow application of water
quality 'criteria that are less stringent
than the "Drinking" criteria and values
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
in waters that have been designated for
use as public water supplies, is not
consistent with 40 CFR 131.11(a),
Second, to the extent that States or
Tribes believe that certain waters of the
Great Lakes System have not and will
not be used for public drinking water
supplies, they may seek to change the
uso designation of such segments
consistent with EPA regulations in 40
CFR part 131.10. Notwithstanding any
such changes, of course, regulatory
authorities issuing NPDES permits must
insure that point source discharges will
not interfere with attainment of all
downstream water quality standards.
Consequently, when establishing
controls on discharges of pollutants into
waters of the Great Lakes System that
have not bean designated for use as
public \vator supplies, Great Lakes
States and Tribes must consider any
effects that such discharges will have on
waters of the Great Lakes System that
have been designated for use as public
water supplies.
The approach taken in the proposed
Guidance regarding the applicability of
criteria and values for human health
ensures that water quality criteria shall
ba applied to protect human health
throughout the Great Lakes System. EPA
recognizes that this approach is more
restrictive than EPA's current National
policy. However, as explained above,
EPA believes that general application of
all criteria and values throughout the
entire Groat Lakes System is required to
promote consistent water quality
standards in the Great Lakes System.
EPA requests comment on the
proposed provision generally requiring
basin-wide application of the Tier I
criteria and Tier n values regardless of
existing usa designations. EPA believes
that the use designations for most
waters within the Great Lakes System
currently include protection of aquatic
life and recreational uses. EPA
recognizes, however, that there are a few
waters within the Great Lakes System
that are not currently designated to
protect these uses. EPA requests
comment on all aspects of this issue
including the proposed applicability
provisions, the exceptions discussed
above, and any suggested alternatives.
d. Other Options Considered. The
Steering Committee believed that the
Great Lakes States and Tribes should be
allowed to apply criteria and values
other than the Tier I criteria and Tier n
values for chronic aquatic life when
Justified through a use attainability
analysis pursuant to 40 CFR part 131.
The Steering Committee also believed
that this exception should be limited to
application of criteria and values for
pollutants that are notbioaccumulative
chemicals of concern (BCCs). The
Steering Committee developed this
exception because the chronic aquatic
life methodologies are based on
exposures of 96 hours and there may be
sites within the Great Lakes System
where physical and hydrologic
conditions preclude aquatic life from
remaining in the particular site for that
time period. Therefore, some members
of the Steering Committee believed that
uniform application of the criteria and
values for chronic aquatic life health
would be more stringent than necessary
to protect aquatic life in those specific
sites.
EPA has decided to address this issue
in procedure 1 of appendix F of the
proposed Guidance on site-specific
modifications, rather than in § 132.4 on
applicability. EPA's existing regulations
allow modification of designated uses ;
based on the factors specified in 40 CFR
131.10(g). Because the stringency of
water quality criteria that must be
applied to a water body under EPA's
current National regulations is
dependent upon the use that is
designated for the water body, a
modification of a use pursuant to 40
CFR 131.10(g) may allow for application
of less stringent criteria.
As explained above, however, the
proposed Guidance differs from EPA's
current National regulations in that the
proposed Guidance generally requires
application of water quality criteria and
values throughout the Great Lakes
System that will be protective of human
health, wildlife and aquatic life,
regardless of State or Tribal use '
designations. In light of this approach,
EPA believes that exceptions from the
requirement to apply the criteria and
values for aquatic life may be equally
but more appropriately addressed in
procedure 1 of appendix F on site-
specific modifications. Procedure 1 of
appendix F proposes a procedure by
which States or Tribes may develop site-
specific modifications to the criteria and
values derived from the Great Lakes
methodologies for chronic aquatic life to
reflect local hydrologic and physical
conditions within the Great Lakes
System. However, EPA specifically
invites comment on the alternative
approach to address these site-specific
conditions through Use attainability
analyses and whether State or Tribal use
designations should play a more
prominent role in the Great Lakes
System than is envisioned by the
proposed Guidance. •
2. Implementation Procedures
a. Applicability of the Proposed
Guidance. Section 132.4(e) of the
proposed Guidance requires States to
apply the implementation procedures
set forth in appendix F "in establishing
controls on the discharge of any
pollutant to the Great Lakes System by
any point source," with two exceptions.
First, under § 132.4(e)(l), Great Lakes
States and Tribes are not required to
apply any of the proposed
Implementation Procedures to wet-
weather discharges. Second, under
§ 132.4(e)(2), Great Lakes States and
Tribes have discretion to decide
whether to apply procedures 1,2, 3,4,
5, 7, 8 and 9 to establish controls on the
discharge of any pollutant set forth in
Table 5. However, regulatory authorities
must apply the whole effluent toxicity
(WET) requirements set forth in
procedure 6 in establishing controls on
the discharge of all effluents to the Great
Lakes System. Section 132.4(e)(2)
provides that any implementation
procedures adopted by a Great Lakes
State or Tribe shall conform with all
applicable Federal, State, and Tribal
requirements.
b. Justification for the Proposed'
Approach. The proposed Guidance
generally requires application of the
Implementation Procedures set forth in
appendix F throughout the Great Lakes
System. As discussed in sections I and
n.E.l of this preamble, this condition is
necessary to implement the primary
goal of the CPA—to establish a more
uniform level of water quality control
throughout the Great Lakes System.
The proposed Guidance provides
"exceptions in two situations: In
establishing controls on the discharge of
pollutants by wet-weather point
sources; and in establishing controls on
the discharge of any pollutant identified
in Table 5, or any other pollutant for
which the Great Lakes State or Tribe
demonstrates that one or more
metho'dologies or procedures are not
scientifically defensible. The
justification for each exception is
discussed below.
i. Wet-weather Point Source
Discharges. Section 132.4(e)(l) of the
proposed Guidance provides that the
Great Lakes States an A Tribes are not
required to apply the proposed
Implementation Procedures in
establishing water-quality-based
controls on wet-weather point source
discharges to the Great Lakes System. A
wet-weather point source is defined in
§ 132.2 of the proposed Guidance as
a point source which is either an outfall from
a municipal separate storm sewer as defined
at 40 CFR 122.26(b)(8), a storm water
discharge associated with industrial activity
as defined at 40 CFR 122.26(b)(14), or a
combined sewer overflow. A combined sewer
overflow is a flow from a combined sewer in
excess of the interceptor or regulator capacity
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FederaT Register;/ Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
20841
which is discharged into a receiving water
body without going to a publicly owned
treatment works; Combined sewer overflows
occur prior to the headworks of a treatment
facility. A storm water discharge associated
with industrial activity which is mixed with
process wastewater shall not be considered'a"
wet-weather point source. , , .
'EPA believes that allowing the States
and Tribes the discretion to apply the
proposed procedures in wet-weather
situations on a.site-specific basis where
appropriate is riecessary due to the
significant differences that exist ••" ,
between wet-weather point source
discharges and dry-rweather point source.
discharges. For example, in order to
, implement water quality standards for a
particular pollutant in a particular
.receiving water, it is necessary to
account-for a variety of conditions ••
including the rate, volume and duration
of effluent flow into the receiving water;
the nature arid volume of pollutants in
the effluent; the flow rate and volume of
the receiving water; and the background
concentrations of pollutants hi'the •"•
receiving water. Because these , '
conditions remain fairly constant during
dry-weather periods, EPA has been able
to develop general guidance on many
implementation procedures that can be
applied to most point source discharges.
See, e.g., "Technical Support Document
for Water Quality-based Toxics Control"
(1991); "Technical Guidance of
Supplemental Stream Design Conditions
for Steady State Modeling" (1989);
"Technical Guidance Manual for
Performing Waste Load Allocations,
Book n Streams and Rivers, Chapter 3
Toxic Substances" (1984); "Water,
Quality Standards Handbook" (1983).
The conditions associated with wet-
weather point source discharges, in
'.contrast, are intermittent and occur
during and immediately following wet-
weather events. Consequently, the rate ,
and volume of flow in the receiving .
water may rapidly fluctuate during such
discharges. Furthermore, the degree'of
•fluctuation of pollutants within the
receiving water also may vary
depending on a wide range of factors
including the magnitude and duration
of arid time period between rainfall
events; the amount and flow of storm
water being discharged as compared to
the amount and flow of the receiving
water; the soil conditions and Land use
activities near the receiving water; and
the degree to which land near the
: receiving water is impervious to
precipitation. See 55 FR 47990, 48038
(Npv. 16,1990); 53 FR 49416,4944.4
(Dec. 7,1988).
• A second cause of the variability
associated with wet-weather is that
much of the effluent discharged during
wet-weather consists of storm water
run-off containing pollutants whose
source, nature, and extent varies
'according to local land.use activities as
well as the other factors described above
that cause variability in receiving
waters. See 55 FR 48038r 49443 (Nov.
16,1990). Discharges from combined
sewer overflows, for example, include
pollutants from'domestic waste such as
bacteria, nutrients, BOD, solids and
floatables which, due to the intermittent
nature of storm events, are
intermittently discharged in combined
sewer overflows and in storm water and
can vary considerably. -
v Due to the high degree of variability
associated with wet-weather conditions,
EPA has not developed a general set of
implementation procedures for uniform
application to all wet-weather point
source discharges. Instead, EPA's
National policy has been to allow
permitting authorities familiar with'
local wet-weather conditions to .-,
establish site-specific controls on wet-
weather point source discharges to
implement technology-based
requirements based on the permitting
authorities' best professional judgment
and to meet water quality standards. See
National Combined Sewer Overflow ,
Strategy, 54 FR 37370 (September 8,
1989). However, permittees with
combined sewer overflows generally are
expected to implement the nine .
minimum' controls listed in EPA's .draft
Combined Sewer Overflow Control
Poh'cy (see 58 FR 4994 (January 19,
1993)), and to achieve volume or mass
reductions, overflow restrictions or
other limits as necessary to achieve '
water quality standards. EPA believes .
.that the variability associated with wet-
weather point source discharges on a
National level is also present with
regard to wet-weather point source
discharges into the Great Lakes System.
Consequently, consistent with EPA's
National policy, the proposed Guidance
does not require but allows the Great
Lakes State or Tribe discretion to apply
any of the proposed procedures in
establishing controls on wet-weather
point source'discharges on a site-
specific baisis. .-.'.'..
Although EPA is not proposing to
require the .Great Lakes States or Tribes
to apply any of the proposed
Implementation Procedures to wet-
weather point source ^discharges, EPA
believes that some of these procedures
could technically be applied to establish
controls on wet-weather point source
discharges. For example, the proposed
procedures for variances Could be
applied to both dry-weather and wet- -
weather point source discharges. In :
contrast, the proposed procedure for
determining reasonable potential to
.exceed water quality-based effluent
limitations may not be fully applicable
to wet-weather discharges. This is
because the statistical methods set forth
in the procedure are based on the
assumption that the effluent "
concentration and receiving water flow
behave independently; that is, for dry-
weather discharges, there is an equal
likelihood that a high or low effluent
concentration could occur at any
receiving water flow. However, in the
case of wet-weather, both the effluent
concentration and receiving water flow ,
are influenced by rainfall and therefore
do not always behave independently.
EPA requests comment on all aspects of
this proposed exclusion for wet-weather
discharges including: the
appropriateness'of-the. proposed
exclusion for wet weather discharges;
the definition of wet-weather point
sources; which implementation
procedures could appropriately be
applied in establishing regulatory
controls on wet-weather point source
discharges; and whether the final rule
.should require permitting authorities to
apply any particular1 procedures in
establishing controls on wet-weather
discharges in the Great Lakes System.
Section 132.4(e)(l) of the proposed
Guidance requires that "any procedures
applied in lieu of these implementation
procedures shall be consistent with all
applicable Federal, State, and Tribal
requirements." Accordingly, even .
though permitting authorities are not-
required to apply the Great Lakes
Implementation Procedures in
establishing controls on wet-weather
point source discharges^all permits
must still contain any limitations and •
conditions necessary to ensure
compliance with the Clean Water Act
arid implementing Federal and State
regulations. Furthermore, under
§§132,3 and 132.4(c) of the proposed
Guidance, all criteria arid values and
site-specific modifications thereof apply
for all purposes specified in the Clean
Water Act for'Criteria developed under
section 304(a), including .decision-
making regarding wet-weather point - ,
source discharge's.
, As part of EPA's National activities
regarding combined sewer discharges,
EPA is evaluating whether the present
assumptions used in the water quality
criteria, water quality standards, total
maximum daily load/waste load
.allocation, and permitting processes are
appropriate for wet-weather discharges.
Upon completion of this evaluation,
EPA intends to issue guidance either .
affirming the scientific validity of those
present assumptions that it determines
are appropriate for wet-weather
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20842 Federal Register / Vol. 58, No. 72 /Friday, April 16, 1993 /Proposed -Rules
discharges or, where present
assumptions are not appropriate,
modifying the assumptions as necessary
to account for wet-weather situations.
Additionally, as discussed in section
I.G, of this preamble, EPA has convened
a separate multimedia work group (the
Great Lakes Toxics Reduction Initiative)
to determine whether additional
guidance for the Great Lakes System
should ba developed in several areas,
including specific implementation
guidance for wet-weather point and
nonpolnt source discharges. In the event
that uniform National procedures or ,
guidance to implement water quality
standards in permits are developed
specifically for wet-weather point
source discharges, EPA will evaluate the
appropriateness of application of such
procedures to the Great Lakes System.
IL Excluded Pollutants. Section
132,4(g) provides that States and Tribes
are not required to use the proposed
Implementation Procedures to develop
water quality-based effluent limits for a
pollutant if it is listed in Table 5 of the
proposed Guidance, or if the State or
Tribe demonstrates that applying one or
moro methodologies or procedures to
the pollutant is not scientifically
defensible. EPA recognizes that some of
Iho Groat Lakes Implementation
Procedures in appendix F could
technically be applied in establishing
controls on the discharge of some or all
of the pollutants listed in Table 5. For
example, procedure 2 (Variances from
Water Quality Standards) could be
applied in determining whether to, grant
a variance from water quality standards
to a point source discharger of any
pollutant.
Nevertheless, §132.4(e)(2) of the
proposed Guidance provides that, with
the exception of procedure 6 (Whole
Effluent Toxlcity Requirements for Point
Sources), the Great Lakes States and
Tribes may, but are not required to,
apply the proposed Implementation
Procedures in establishing controls on
the discharge of any pollutant set forth
In Table 5 of the proposed Guidance.
The rationalo for requiring whole
effluent toxidty testing for all
discharges, including those containing
Table 5 pollutants, is discussed in
section VHLF, below. Table 5 contains
sixteen pollutants: Alkalinity, ammonia,
bacteria, biochemical oxygen demand,
chlorine, color, dissolved oxygen,
dissolved solids, hydrogen sulfide, pH,
phosphorus, salinity, sulfide,
temperature, total and suspended solids,
and turbidity. The basis for the general
exception for Table 5 pollutants,
including the rationale for selection of
the pollutants, is discussed in section
II.F of this preamble. The exclusion of
additional pollutants on the basis of
scientific defensibility is also discussed
in section H.F.
EPA specifically requests comment
on: Today's proposed approach to allow
States and Tribes the flexibility to select
implementation procedures for Table 5
pollutants as long as they are consistent
with Federal, State, and Tribal
requirements; which of the Great Lakes
Implementation Procedures could be
applied in establishing regulatory
controls on the discharge of any or all
of the pollutants listed in Table 5; and
whether regulatory authorities should
be required to apply any or all of the
Great Lakes implementation procedures
in establishing controls on the discharge
of any or all of the pollutants listed in
Table 5. EPA also invites comment on
the 132.4(g) exclusion for scientific
defensibiiity as applied to the
Implementation Procedures in appendix
F, discussed further in section H.F,
below.
3. Antidegradation Policies
The proposed Guidance requires
Great Lakes States and Tribes to apply •
the antidegradation policy adopted
pursuant to § 132.4(a)(6) for all
applicable purposes under the Clean
Water Act, including 40 CFR 131.12, for
all pollutants. Unlike other parts of the
proposed Guidance, which focus on
regulatorily determined desirable levels
of water quality, the antidegradation
policy focuses on actual water quality.
Traditionally, antidegradation policies
have operated independently of, or as a
backstop to, individual water quality
criteria adopted to protect particular
uses. Hence, the reasons for
distinguishing between particular
pollutants for purposes of prescribing
methodologies for criteria development
do not appear particularly relevant to
the question of the applicability of the
antidegradation policy. EPA requests
comments on the proposal to make
appendix E applicable to all pollutants.
F. Excluded Pollutants
The proposed Guidance generally"
requires application of the criteria
development methodologies in
appendixes A, B, C and D, and the
Implementation Procedures in appendix
F for all pollutants except for the 16
pollutants listed in Table 5 and any
pollutant other than those in Table 5 for
which the Great Lakes State or Tribe
demonstrates that application of one or
more guidance procedures to the given
pollutant are not scientifically
defensible. The pollutants listed in
Table 5 are: alkalinity,,ammonia,
bacteria, biochemical oxygen demand
(BOD), chlorine, color, dissolved
oxygen, dissolved solids, hydrogen
sulfide, pH, phosphorus,.salinity,
sulfide, temperature, total and
suspended solids, and turbidity.
With regard to the exclusion of
pollutants in Table 5, the States and
EPA have had many years of extensive
, experience in control of these
pollutants. For example, regulatory and
voluntary programs to control
phosphorus began in the 1960s and
continue to the present. Additionally,
all of the Great Lakes States have
adopted, and EPA has approved,
numeric water quality criteria for these
pollutants. Based on this extensive
experience, the Steering Committee of
the Great Lakes Water Quality Initiative
believed that efforts should not be made
to develop criteria, methodologies, and
implementation procedures that could
uniformly be applied to these pollutants
given the limited time and resources
available to complete the work of the
Initiative.
Based on these considerations, the
Initiative Committees believed that
regulatory authorities should retain the
flexibility in their existing water quality
programs to address these pollutants on
a site-specific basis. EPA believes that
the existing EPA-approved State water
quality standards for these pollutants
are adequate to protect aquatic life,
human health, and wildlife in the Great
Lakes System. Although variations do
exist in the criteria and implementation
procedures fpr these pollutants in the
Great Lakes States, EPA also 'believes
that the variability is not sufficient to
adversely affect the protection of aquatic
life, human health, or wildlife in the
Great Lakes System because of the
extensive experience of EPA and the
States in the regulation of these,
pollutants.
Additionally, uniform application of
the methodologies and implementation
procedures is not appropriate for s'ome
of the excluded pollutants in Table 5 ,
because of technical reasons. F6r
example, modifications to the proposed,
criteria development methodologies
would be:required to derive criteria or
values for alkalinity and color. Given
the limited time and resources available
to derive these additional
methodologies and the extensive
regulatory experience in controlling
these parameters, EPA believes that the
existing State and Federal requirements
should continue to be used for these
pollutants. _,
EPA may consider expanding the •
methodologies and procedures to
specifically address these pollutants in
the future, and invites comment on:
Whether the final rules should require
some or all of the proposed Guidance or
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Federal Register / Vol. 58, No. 72 / Friday,; April16, 1993 /Proposed Rules
20843
alternative requirements to.be applied to
any of the identified pollutants; and
identification of any modifications that
would be necessary to apply the
proposed methodologies or procedures -
to any of these pollutants.
EPA recognizes that some of the
excluded pollutants are identified in .
Annex 1 of the Great Lakes Water
Quality Agreement (GLWQA). As
discussed in sections I and in.B.l.b,
EPA has indicated its intention to seek
modifications to the GLWQA, where
necessary, to specify- criteria and
procedures for these pollutants that are
scientifically based and protective of
aquatic life, human health and wildlife:
in the Great Lakes System.
Section 132.4(g) also provides that the
Great Lakes States and Tribes may. but
are not required to, apply the proposed
criteria methodologies and
implementation procedures to tiny
pollutant for which the regulatory
authority demonstrates that one or more
procedures in the Guidance are not '.
scientifically defensible. The reason for
this exclusion is that there may be^ ,
pollutants identified in the futureTfor
which some of the methodologies or
procedures being proposed today may
not be technically appropriate; Under
these circumstances, EPA wishes to
provide sufficient flexibility for
permitting authorities to address these
pollutants on a case-by-case basis.
The exclusion related to. scientific
defensibility may be used by a Great
Lakes State or Tribe either when
developing numeric water quality
criteria, interpreting narrative criteria,
or implementing narrative or numeric
criteria in individual NPDES permits.
For example, if a Great Lakes State or
Tribe determines that a procedure for
modifying a,water quality criterion is
not scientifically defensible when
applied to a specific pollutant, they
would provide the demonstration
^described in §132.4(g) in their
submission of the new or revised ,
criteria to EPA under section
303(c)(2)(A) of the Clean Water Act. If
the issue arises during development df _
a TMDL based on interpretation of a
narrative criterion, the Great Lakes State
or Tribe could provide the
demonstration at the time a TMDL
developed pursuant to procedure 3 is
submitted to EPA for review. Similarly,
if the Great Lakes State or Tribe
determines that an alternative
implementation procedure is necessary
to develop water quality-based effluent
limits in an individual permit to
implement narrative or numeric criteria
for a particular pollutant based on this
exclusion, they would submit the
supporting demonstration for EPA
review as part of the submitted TMDL
or proposed NPDES permit. These
demonstration.submissions should -
include: Identification of the provision
of the proposed Guidance that the
regulatory authority has not applied to
a pollutant; demonstration that
application of the provision to the
pollutant is not scientifically defensible; •
and a description of the scientifically
defensible alternative method to be used
in place of the provision in the
proposed Guidance.
EPA invites comment on all aspects of
the exclusion in § 132.4(g), including
whether the final Guidance should
specify minimum requirements for use
of this exclusion, demonstration
elements, or procedures for EPA review
of these submissions.
G. Pollutants of Initial Focus for Criteria
Development, and Bioaccumulative
Chemicals of Concern
The Guidance being proposed today,
while generally applying to all
pollutants (except for the pollutants in
Table 5 for some provisions), was ..
structured to provide an initial focus on
138 pollutants listed in Table 6. The
pollutants listed in Table 6 were
identified by the Steering Committee to
be those known or suspected of being of
primary concern in the Great Lakes
basin.Table 6 is composed of: -
1. The 126 pollutants that have been
identified by EPA as priority toxic
pollutants. The listing appears as
appendix A of 40 CFR part 423, The
.priority pollutant list identifies toxic
pollutants of concern on a National
basis. It has served as a basis for
numerous EPA actions, including: the
selection of pollutants for development
of water quality criteria under section
304(a) of the Clean Water Act; the
development of technology-based
effluent guidelines under section 301 of
the Clean Water Act; the listing of
impaired waters under section 304(1) of
the Clean Water Act; and as a basis for
determining State compliance with
section 303(c)(2)(B) of the CWA which'
requires. States to adopt numeric criteria
for toxic pollutants of concern in State
, waters. . '
2. Pollutants listed in the Great Lakes
Water Quality Agreement of 1978 (as
amended by the Protocol signed
November 18,1987). The Agreement
identifies pollutants of concern in the
Great-Lakes System or parts thereof.
Specifically, Table 6 of the proposed
Guidance includes most of the
pollutants for which there are "Specific
'Objectives" in Annex 1 of the •
Agreement; However, Table 6 excludes
16 of the entries in Annex 1: eight are -.
pollutants contained in Table 5 of the
proposed Guidance and were omitted
for the reasons discussed in section H.F
of this preamble. Examples in this group
include total dissolved solids, pH, and
temperature. The remaining eight ;
entries in Annex 1 were omitted
because they did not list specific
pollutants by name, but rather identified
undifferentiated groupings of pollutants
that could not be used to establish a
meaningful focus for individual ;-,
pollutants in the Great Lakes Water
Quality Initiative. Examples in this
group include "unspecified organic
compounds," "other pesticides," and
"unspecified non-persistent toxic
substances and complex effluents;"
3. Pollutants categorized as IA or IB
in the Categorization of Toxics in Lake
Ontario (July 1988) under the Lake
Ontario Toxics Management Plan, or in ,
the Categorization of Toxic Substances
in the Niagara River (June 1990) under
the Niagara River Toxics Management
Plan. The Lake Ontario and Niagara
River Toxics Management Plans identify
pollutants of concern in a specific Great
Lake or in a connecting channel plan,
that may also be of concern in upstream
lakes or connecting channels. Category
IA and IB pollutants are those pollutants
for which ambient data are available
and an enforceable (IA) or
unenforceable (IB) standard is exceeded.
4. Pollutants included on a case-by- • '••.
case basis. Table 6 includes three
pollutants solely on this basis:
Malathion;2,4-D(2,4v
Dichlorophenoxyacetic Acid); and
Chlorpyrifos. EPA has developed .
National water quality criteria guidance
documents for the protection of aquatic
life for these pollutants: ambient, water
quality criteria for Malathion and 2,4-D
were published in "Quality Criteria for
Water" ("Red Book"), U.S. EPA, 1976
(PB-263943). Ambient water quality
criteria for Chlorpyrifos were published
at 51FR 43666 (December 3,1986). ,
These commonly used pesticides or
herbicides were included in Table 6
because of their known or suspected
presence or widespread use in the Great
Lakes System.
The primary purpose of the Initiative
Committees in specifying pollutants in
Table ,6 was to provide an initial focus
for criteria development and the
calculation of bioaccumulation factors
in the Great Lakes System. The
pollutants included in Table 6 were not
intended to be a comprehensive
inventory of all pollutants present, used
or manufactured in the Great Lakes
System. If the listing included as Table
6 was to become such an exhaustive
inventory, it would not be useful for
providing this initial focus.
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Federal Register / Vol. 58, Nov 72 /. Friday, April 16, 1993 / Proposed Rules
aesan
Tho proposed Guidance provide
initial focus on the Table 6 pollutants in
the following three ways. First, the
pollutants for which EPA and the States
have applied the proposed criteria
methodologies to derive numeric water
quality criteria—that is, the pollutants
In Tables 1, 2,3 and 4—were selected
from the list of pollutants in Table 6.
EPA and the Initiative Committees
bolieve that the pollutants for which
EPA establishes minimum water quality
standards, as required by the Great
Lakes Critical Programs Act of 1990,
should, as a minimum, include those
known or suspected of being of primary
concern in the Great Lakes basin—that
is, those in Table 6. In selecting from the
Table 6 pollutants for which numeric
water quality criteria would be
calculated for inclusion in the proposed
Guidance, EPA and the Initiative
Committees considered a number of
factors in addition to those used to
dsvelop Table 6. These other factors,
described in sections Ht, V and VI of
this preamble, include data availability, x
chemical characteristics, and
environmental effect on the Great Lakes
System.
Second, EPA and the Great Lakes
States limited calculation of human
health bioaccumulatipn factors fBAFs)
for the proposed Guidance to Table 6
pollutants, BAF calculation is necessary
when developing water quality criteria
to protect human health and wildlife.
Tho BAFs calculated for use in the
proposed Guidance will facilitate State
and Tribal development of such criteria,
In developing Table 6, EPA and
Initiative participants developed human
health BAFs for each of the 138
pollutants. These BAFs are described in
tha technical support document,
"Derivation of Proposed Human Health
and Wildlife Bioaocumulation Factors
for tha Great Lakes Initiative," available
in the administrative record for this
rulomaking. Copies are also available as
described in section m of this preamble.
BAF calculation is also necessary to
determine bioaccumulative chemicals of
concern (BCCs), which are discussed
below.
The third way that Table 6 affects the
initial focus of this Guidance is in
determining when States, Tribes, and/or
permitters must generate data necessary
to calculate Tier n values used in
developing water quality-based effluent
limits. Procedure 5.D ofthe proposed
Implementation Procedures in appendix
F requires that permitting authorities
generate, or have permitters generate,
the data necessary to calculate Tier H
values for pollutants in Table 6 for
which there is no Tier I criterion or Tier
II value if the permitting authority
determines based on a specified
screening approach that a discharge
causes, has the reasonable potential to
cause or contributes to an excursion
above a State water quality standard.
EPA invites comment on the listing of
pollutants contained in Table 6 and on
the basis for including pollutants in
Table 6. EPA also invites comment on
whether pollutants should be deleted
from Table 6 or added to Table 6,
including the pollutants listed in the
Great Lakes Water Quality Agreement,
Annex 10, Appendix 1 (Hazardous
Polluting Substances) or Appendix 2 '
(Potentially Hazardous Polluting - "
Substances) or pollutants categorized as
ID or IE in the Categorization of Toxics
in Lake Ontario or in the Categorization
of Toxic Substances in the Niagara
River. Category ID pollutants are those
pollutants for which ambient data are
available but for which a complete
categorization was not possible due to
detection limits. Category IE pollutants
are pollutants for which ambient data
are available but no criterion is known
to be available. ......
EPA also invites comment on whether
the requirements in implementation ,
procedure 5.D should be focused on a
limited list of pollutants, such as the
138 pollutants in Table 6 or whether
Procedure 5.D should be extended to .
apply to any other pollutants for which
water quality criteria or values are not
available.
As discussed in more detail in
sections LA and I.D of this preamble,
the Initiative Committees were
particularly concerned about pollutants
which exhibited system-wide, impacts,
such as mercury and PCBs, dins to their
propensity to bioaccumulate in* the food
chain and/or persist throughout the
Great Lakes System. The Steering
Committee wanted to prevent additional
chemicals with similar tendencies from
reaching levels that would also impact
the Great Lakes System. The Technical
Work Group recommended utilizing a
bioaccumulation factor methodology
which incorporates metabolism and
other physicochemical properties as a
mechanism by which to identify highly
bioaccumulative chemicals which could
cause system-wide impairments of
beneficial uses. The Steering Committee
selected a bioaccumulation factor (BAF)
of 1000 as an indicator of a pollutant's
ability to be highly bioaccumulative. A
pollutant with a BAF greater than 1000
was believed by the Steering Committee
to have a high potential to be found in
aquatic organisms of the Great Lakes
System and therefore to have the
potential to cause a significant risk to
the health of the aquatic life _and
consumers of the'aquatic life such as •
wildlife and humans inhabiting the
Great Lakes basin. Those pollutants
with a bioaccumulation factor greater
than 1000, after considering metabolism
and other properties, are called
bioaccumulative chemicals of concern
(BCCs) in the proposed Guidance. BCCs
are subject to more stringent controls
than other chemicals, as explained in
section I.D of this preamble. The
Guidance (in § 132.2) defines BCCs as
follows:
. Bioaccumulative chemical of concern
(BCC) is any chemical which, upon entering
the surface waters, hy itself or as its toxic '
transformation product, bipaccumulates in
aquatic organisms by a human health
bioaccumulation factor greater than 1000,
after considering metabolism and other
physicochemical properties that might
enhance or inhibit bioaccumulation, in
accordance with the methodology in
appendix B to part 132. BCCs include, but are
not limited to the pollutants identified as
BCCs in Table 6.
As described above, EPA and the
Initiative Committees developed BAFs
for each ofthe 138 pollutants in Table
6. Thirty-eight (38) pollutants were
found to have BAFs greater than 1000
under the assumption of 5.0 percent
lipid content that is used for human
health criteria development. For ten of
these 38 pollutants, however, EPA
believes the BAF may need to be
adjusted in accordance with section
VI.D.5 of the Methodology for
Development of Bioaccumulation
Factors in appendix B, which states:
5. Both human health and wildlife BAFs
should be reviewed for consistency with all
available data concerning the
bioaccumulation of the chemical. In
particular, information on metabolism,
molecular size, or other physicochemical
properties which might enhance or inhibit
bioaccumulation should be considered. The
BAFs may be modified if changes can be
justified by the data. .
EPA identified the following concerns
during'application of the proposed
methodology for defining BAFs:
—Six polynuclear aromatic
hydrocarbons (3,'4-benzofluoranthene,
11,12-benzofluoranthene,
benzo[a]pyrene, 1,12-benzoperylene,
l,2:5,6-dibenzanthracene,
indeno[l,2,3-cd]pyrene) are 5-ring
PAHs. Field-measured BAFs for two
3-ring and two 4-ring PAHs ranged '
from 17 to 228, and it seems unlikely
that the addition of another ring will
increase the BAF to over 1000. The
four measured BAFs that are available
for PAHs are substantially lower than
the BAFs that are predicted from Log
P for those chemicals.
—Metabolism is likely to reduce both
the BAF and food chain multiplier „
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20845
.enough to cause the BAF to be less
than 1000 for two chemicals (4-
chlorophenyl phenyl ether, dibutyl
phthalate). •='.'"_.
—The BGF for one chemical (phenol)
was measured using radiolabeled
chemical. Even though the parent
chemical was verified, the resulting
predicted BAF is so much higher than
the BAF predicted from.Log P that it
• is doubtful that the BAF for this ,
chemical is above 1000.
—The BCF for one chemical (toluene)
:was measured using radiolabeled
chemical. The parent chemical was
not verified and the resulting
predicted BAF is so much higher than
the BAF predicted from Log P that it
is doubtful that the BAF for this; •
chemical is above 1000. ..-.'•
For these reasons, EPA is proposing to
list the above ten chemicals as potential
BCCs rather than BCCs. These ten
pollutants are listed in part B of Table
6. The special regulatory provisions for
BCCs in the proposed Guidance would
not apply to these ten pollutants,
although pursuant to section 510 of the
' Clean Water Act, .the Great Lakes States
or Tribes may also apply these ,
provisions to any other pollutant,
including the list of potential BCCs. The
detailed derivation of the BAFs for all ;
pollutants.on Table 6 including the
identified BCCs and potential BCCs is
described in the technicaljsupport
document, "Derivation of Proposed :
Human Health; and Wildlife
Bioaccumulation Factors for the Great {
Lakes foitiative," which is available in :
the administrative record..
The 28 pollutants with BAFs greater
than 1000 for which EPA does not have
the above concerns are listed in part A
of Table 6; The special regulatory
, provisions for BCCs in the proposed
Guidance would apply to these 28
BCCs, as well as to any other pollutant
that the State or Tribe determines has a
BAF greater than 1000, using .the .
. Methodology for Development of
Bioaccumulation Factors in appendix B
to part 132.
EPA invites comment on the choice of
a BAF of 1000 at 5.0 percent lipids as
the level which defines a BCC. The
.selection of a BAF of 1000 is a risk
management decision that involves
weighing information and policy
considerations (rather than a risk
assessment assumption that results from
;-a scientific analysis). The Steering •:.'••
Committee made its recommendation on
the basis of information available to
them as managers of water quality
programs. EPA is proposing this
recommended cutoff of 1000 as an
appropriate.numbef to use for .
determining when there is a likelihood
of relatively high exposure to humans
and wildlife as a result of fish
consumption. EPA recognizes that other •"
numbers could be selected as a cutoff.
During the deliberations of the;Steering
Committee, for 'example, alternative
levels of 308 and 100.were suggested. A
BAF of 308 represents the approximate
value at which exposure from
consumption of fish exceeds exposure
from consumption of drinking water,
under a human health criteria exposure
assumptions of 6.5-gm/day of fish
consumption and 2 L per day of
drinking water consumption. Eight of
the pollutants in Table 6 have proposed
BAF values between 308 and 1000.
Sixteen of the pollutants on Table 6
.have proposed BAF values between 100
and 300. For reference purposes, a BAF
of 1000 represents the point at which
bioaccumulatiori due to dietary uptake
in fish begins to be significant. Below
this level, BAFs and BCFs are predicted1
to be nearly the same because virtually.
all bioaccumulation occurs as the result
of pollutants from the. water.
EPA invites comment oh the proposed
BAF level of 1000 and any alternative
BAF levels for use in defending BCCs,
EPA also invites comments on the lists
of BCCs .and potential BGCs, the
methodology used to derive them, and .
all aspects of the issues related to BCCs.
In particular, EPA'invites comments on
whether any or all of the potential BCCs
should be listed as BCCs and any
additional data-relevant to these
determinations.: ' . ,
The special regulatory provisions for .
BCCs in the proposed Guidance include
portions of the antidegradation policy in
appendixE, andprocedure 3 (Total
Maximum Daily Loads) and procedure 8
(WQBELs Below the Levels of
Detection) in appendix F, The specific, ,
reasons for applying these provisions to."
BCCs are provided in sections I.D., VII,
VHI.E, and VHI.H of this preamble. EPA
invites comment on the manner in
which these provision's are based, in
part, on the definition of BCCs.
H. Adoption Procedures ;
Section 118(c)(2)(C) of the Clean
Water Act requires the Great Lakes
States to adopt water quality standards,
antidegradation policies, and • • '. •
implementation procedures.for waters
within the Great Lakes System which
are consistent with the final Guidance.
If a Great Lakes State fails to adopt
consistent provisions within two years
of EPA's publication of the final ,
Guidance, EPA is required to. , .
promulgate such provisions within the
same, tworyear period. -
Section 132.5 of the proposed
Guidance specifies the procedures for : •
State and Tribal submissions, and for
EPA review and approval or disapproval.
of these submissions under part 132.
Where possible, EPA has patterned the „
submission and approval process in
proposed § 132.5 after the processes
now in place for the water quality
standards and NPDES programs,
pursuant to sections 303 and 402 of the .
Clean Water Act, and believes the
procedures in proposed § 132.5 satisfy
the minimum procedural requirements
of those programs. Therefore, EPA's
review and approval of these , • "••:','•'
submissions will constitute approval ,
under section 118 of the Clean Water
Act, approval of the submitted water
quality standards pursuant to section
303 of the Clean Water Act, and
approval of the submitted modifications
to the State's NPDES program pursuant ,
to section 402^ the Clean Water Act as
provided in proposed §132.5(f). In this
way, one Submission and approval'
procedure will satisfy all relevant
statutory requirements and thereby
maximize efficient use of State, Tribal,
and EPA time and resources, and
•facilitate public participation. / '
Proposed § 132.5(a) requires the Great
Lakes States and Tribes to adopt and
submit for EPA review and approval the
criteria, methodologies, policies and
procedures developed pursuant to part
132 by a date nojater than 18 months
from the date of final publication, of the
part 132 requirements. Section KB.-. o£ ,
this preamble discusses the application
of the requirements of section ,118 to
Indian Tribes. If an Indian Tribe has not
received authorization to administer the
NPDES program, EPA,or a State .-'.'.
authorized to do so will administer the ;
requirements of part 132 on Indian .
lands and issue permits for discharges
to the Great Lakes System consistent
with this part. States, however,
generally lack authority to administer
NPDES programs on Indian lands, and ,
no State within the Great Lakes basin is
ciirrently authorized to administer the
program on Indian lands. See 40.CFR
123.1(h). EPA is proppsing to establish
this 18-month deadline for State and ,
Tribal submissions in order to allow the
full time available under the statute for
EPA review and approval of
submissions and for.States and Tribes to
correct any identified deficiencies, and
still .allow EPA to meet the section --:-..
118(c)(2)(C) requirement for review,
approval or disapproval and .
promulgation by EPA, if necessary,.
within two years after the final
publication of the Guidance.
Proposed § 132.5(b) identifies four
eleihehts that must be included in the ;
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
Stata and Tribal submissions: (1) The
criteria, methodologies, policies, and
procedures the State or Tribe has
adopted pursuant to part 132; (2) a
cortmcation by the State or Tribal
Attorney General or other appropriate
legal authority of adequate legal
authority to meat the requirements of
part 132; (3) any other information
required for submission of NPDES
program modifications under 40 CFR
123.62; and (4) general information to
aid EPA !n determining whether the
submitted criteria, methodologies,
policies, and procedures are consistent
with the Clean Water Act and part 132,
plus Information on general policies
which may affect the application of the
submitted criteria, methodologies,
policies, and procedures, if any. This
information must currently be included
in any submissions for EPA approval of
Stata revisions to water quality
standards or proposed modifications to
Stata NPDES programs under 40 CFR
131.6 and 123.62.
If a Great Lakes State or Tribe falls to
submit criteria, methodologies, policies,
and procedures to EPA for review,
proposed § 132.5(c) provides that the
requirements of this part will apply to
discharges within the State or Federal
Indian Reservation upon EPA's
publication of the final Guidance in the
Federal Register indicating the effective
date of the part 132 requirements in the
identified jurisdictions. EPA does not
intend to provide at that time an
opportunity for another round of public
comment on tha criteria, methodologies,
policies, and procedures presented in
ihft proposed Guidance. EPA believes
that under these circumstances, today's
public comment period will provide
adequate notice and opportunity for
comment on all issues related to the
criteria, methodologies, policies, and
procedures. Accordingly, EPA will issue
the final Guidance identifying the
criteria, methodologies, policies, and
procedures that apply in the appropriate
jurisdictions.
If a Slate or Tribe submits criteria,
methodologies, policies, and procedures
to EPA for review, EPA will issue a
public notice end provide a 30-day
period for public comment on all State
or Tribal submissions under this part
(proposed § 132.5(d)). This provision is
included to conform with the existing
public comment requirements for
proposed modifications to State NPDES
programs under 40 CFR 123.62(b). After
consideration of public comments, EPA
will either publish a notice of approval
of the submission in the Federal
Register within 60 days or notify the
State or Tribe within 90 days that all or
part of the submission is Inconsistent
with the requirements of the Clean
Water Act or part 132 and identify
.changes necessary to obtain EPA
approval. (Proposed § 132.5(d)(ii).) EPA
will base the approval or disapproval of
the part 132 submission on the
requirements of the Clean Water Act
and part 132. (Proposed § 132.5(e).)
If EPA approves all elements of the
State or Tribal submission, the proposed
Guidance would not require EPA to
promulgate specific provisions for that
State or Tribe in § 132.7. In contrast, if
EPA instead notifies theftState or Tribe
that portions of the submission are
inconsistent with the Clean Water Act
or part 132, as discussed further above,
and the State or Tribe fails to adopt the
• required changes within 90 days after
the notification, EPA will pubh'sh a
notice in the Federal Register
identifying the approved and
disapproved elements of the submission
and a final rule in the Federal Register
identifying the sections of part 132
which will apply in that jurisdiction.
Under these circumstances, EPA will
codify in § 132.6 the part 132 provisions
which will apply in the Great Lakes
States or Tribes that do not submit
approvable regulations.
EPA is proposing this submission
procedure in order to allow time for
EPA review and approval if appropriate,
State or Tribal notice and correction of
any deficiencies, identified during EPA
review as necessary; and EPA
publication of part 132 criteria,
methodologies, policies, or procedures
in whole or in part for the State or Tribe
where required, within two years after
the final publication of the Guidance as
required by section 118(c)(2)(C). EPA
believes there are two advantages to this •
approach. First," it gives States and
Tribes the maximum amount of time
EPA believes is possible under the
statute to make their submissions.
Second, proposed § 132.5 simplifies
the differing processes of promulgating
standards, policies, and procedures by
accounting for the minimum
requirements for EPA approval or
disapproval of water quality standards
and NPDES program modifications
under sections 303 and 402 of the Clean
Water Act. EPA has patterned the
proposed submission procedure after
the well-established procedure for EPA
approval or disapproval of State water
quality standards under section 303(c)
and 40 CFR part 131 and the procedure
for submission of State NPDES program
modifications under section 402 and 40 '
CFR 123^62. These procedures are
familiar to EPA, States, Tribes, the .
regulated community and the public,
40 CFR 131.20 currently requires the
State or Tribe to submit adopted water
quality standards to EPA for review
within 30 days of adoption. Section
303 (c) provides that EPA must approve ,
State water quality standards within 60
days of submission or disapprove the
standards and identify needed changes
within 90 days of submission. If the
State standards are disapproved by EPA,
the State has 90 days to adopt EPA's
required changes. If such action is not
taken, the Act requires EPA to promptly
prepare necessary standards for the
State, The State or Tribal water quality.
standard continues to be effective in the
jurisdiction until EPA promulgates a
new water quality standard. See also 40
CFR 131.21.
The current submission and review
requirements for NPDES program
revisions under section 402 are
described in 40 CFR 123.62. All the
Great Lakes States have approved
NPDES programs; however, to date, EPA
has not authorized any Great Lakes
Indian Tribe to operate the NPDES
program. The procedure for submission
and review of NPDES program revisions
is different in several respects from that
of section 303(c), 40 CFR 131.20 and
131.21, and proposed § 132.5. For
example, 40 CFR.123.62 does not.
provide a detailed timetable for review
of proposed NPDES program revisions.
Additionally, if a State or Tribe fails to
submit materials pursuant to part 132 or
EPA disapproves part of the submission,
proposed §§ 132.5 (c)and (d) require
application of those portions of part 132
to discharges within the State or Federal
Indian Reservation.
Proposed § 132.5 of the proposed
Guidance would provide that
requirements of this part will become
effective within a State or Federal
Indian Reservation if the State or Tribe
fails to make the necessary submission,
or if one or more parts of the submission
cannot be approved by EPA and the
State or Tribe fails to correct the
deficiency upon notice by EPA,
following EPA's publication of the final
Guidance in the Federal Register
identifying the elements of the part 132
requirements that apply in the
jurisdiction and their effective date in .
the jurisdiction. Because the
requirements of part 132 proposed today
will receive full public comment before
the final part 132 Guidance is
promulgated; EPA believes it is both'
unnecessary and an inefficient use of
scarce resources to promulgate separate
notices of proposed and final
promulgation for each State or Tribe for
which EPA must promulgate the part.
132 requirements in whole or in part. By
instead publishing a finalnotice of
promulgation for each such State or
Tribe, EPA will allow the State or Tribe
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20847
approval under proposed § 132.5, i
effective in the State or Tribe until
the maximum available time to submit
the criteria to EPA and still give EPA
sufficient time to publish part 132 •
criteria for the State or Tribe, if \
necessary, within the two-year statutory
deadline. -.'.'"•'
Under the proposed Guidance, the
submission and review procedures in
§ 132.5 will govern EPA review and
approval of water quality standards and
NPDES program revisions for Great
Lakes States and Tribes under part 132
(§123.62(5); EPA does not intend the
provisions of proposed § 132.5 to
change existing Clean Water Act rules
governing the effectiveness of State or
Tribal promulgated requirements. That
is, consistent with the requirements of
section 303(c), if a State or Tribe adopts
a revised water quality criterion which
is submitted to EPA for review and
,itis .
i or Tribe until EPA
disapproves it and promulgates a new
criterion. In contrast, State or Tribal
adoption of NPDES regulations pursuant
to proposed § 132.5 will not become,
recognized parts of the State or Tribal
NPDES program until EPA approves the
proposed modification. Of course,
' according to the proposed § 132.5,
procedure, EPA must either approve a
State or Tribal part 132 submission or
disapprove and publish the final
Guidance identifying the conforming
part 132 requirements that must be
applied to discharges in the Great Lakes
System, for all part 132 criteria, policies,
and procedures, including those which
are NPDES program elements.
EPA also retains the ability to object
to a proposed State or Tribal NPDES
permit that is inconsistent with the
Clean Water Act and NPDES regulations
(40 CFR 123.44(c)(7)), or to withdraw a
State or Tribal NPDES program that
does not comply with the Clean Water
Act and part 123 (40 CFR 123.63(a)).
Once the requirements of this part
become effective, they will provide an
additional basis for EPA objection to the
issuance of a proposed State or Tribal
NPDES permit under § 122.44 or for
withdrawal of NPDES program approval
under §,123.63 if the provisions.have
npt been adequately incorporated into
individual permits or the NPDES
program. To clarify this intention, EPA
,has also proposed conforming changes,
which will apply only to Great Lakes
States and Tribes, to the existing NPDES
permitting regulations in 40 CFR -
122.44(r); 123.25(a)(38); 123.44(c){9);
123.62(f); and 123.63(a)(6). Similarly,
EPA has proposed conforming changes
to the existing water quality standards
regulations in 40 CFR 131,1; 131.5 and
131.21(b) to reflect the submission and
review procedures for adoption of water
quality standards under part 132. .-. •
EPA invites comments on all aspects
of proposed § 132.5, including
comments on alternative procedures
that would be'efficient and effective and
would satisfy the statutory :,"-
requirements. Additionally, EPA
specifically requests comment on
whether the final Guidance should
quality standards elements of part 132
or whether EPA should make this
determination on a case-by-case basis ,
for each part 132,submission; There are •
benefits to either approach.
identification of the NPDES program
elements "and water quality standards
program elements in the final Guidance
could facilitate .uniform treatment of all
part 132 submissions and provide •
certainty to EPA Regions, States, Tribes,
the regulated.community, and the
public concerning the effectiveness of
those .elements during the EPA review
process. On the other hand, flexibility in
this matter is useful in EPA's"experience
because it is sometimes difficult to
distinguish an NPDES! program element
from a water quality standards element
due to differences in State adoption
procedures and terminology. EPA
requests comment on both approaches.
Finally, EPA seeks comment upon
Whether any additional conforming
changes should be made to the existing
NPDES and water quality standards
regulations to implement the :
requirements of proposed § 132.5.
/. Interpretation of "Consistent With"
Section il8(c)(2)(C) of the Clean
Water Act requires the Great Lakes
States and Tribes to adopt water quality"
standards, antidegradation policies, and
implementation procedures for water
within the Great Lakes System which
are "consistent with" the final Guidance
proposed today in part 1;32. Section
132.5(e) of the proposed Guidance
specifies when EPA wiH determine that
a State or. Tribe submission is consistent
with the requirements of part 132.
Generally,-'the proposed Guidance
provides that submitted criteria,
methodologies, policies and procedures
are consistent with part 132 if they are
"equal to or more restrictive than" the
provisions in the final Guidance.
, EPA strongly encourages verbatim
adoption of the final Guidance or "
adoption with only conforming changes,
such as renumbering sections to
conform with the State or Tribal
regulations, or, for example, replacing :
"Great Lakes System" with "Lake Erie
System," Adopting the Guidance
verbatim would facilitate EPA approval
:and guarantee uniformity of these
provisions throughout the Great Lakes
System, especially with regard to the
criteria methodologies. EPA recognizes,
however, that some States or Tribes may
desire to supplement.or modify the final
Guidance which EPA ultimately issues
to incorporate program-specific ,
concerns. Accordingly, in order to .
provide flexibility to State and Tribal ••-•''
regulatory agencies, proposed § 132.5
does not require verbatim adoption of
all elements of the final Guidance as
long as the State or Tribe can
demonstrate that any such modification
will not be less restrictive than the :
required provision in the final
Guidance. Section 132.5(e)(3) clarifies
EPA's intention to evaluate the State
and Tribal submissions on a provision-
by-provision basis by providing that if
States or Tribes adopt provisions'more
restrictive than the final Guidance, the
more restrictive provision may not be
offset by relaxation of other specific
elements of the final Guidance. EPA /
believes that this condition is
appropriate to ensure a minimum level
of consistency in implementation of
these requirements throughout the Great
Lakes System. EPA requests comments, ,
however, on this approach, including
whether and, if so, Under what '.y .
^circumstances the fmal Guidance
should instead.allow relaxation of any •.
particular provisions to offset other
more stringent provisions adopted in .
State or Tribal programs.
EPA recognizes that not requiring • •
verbatim adoption of the final criteria
methodologies, implementation
procedures, and antidegradation
policies will require case-by-case
determinations of the adequacy of a
State or Tribal submission, with the
possibility of minor inconsistencies
developing between approved programs
in the Great Lakes System. Because of •
the length and complexity of the i • .
Guidance, however, EPA also recognizes
that changes beyond conforming
changes may be necessary to enable
; State and Tribal programs to function
appropriately. EPA believes that the
proposed approach balances the
competing interests by providing some
flexibility to the Great Lakes States and
Tribes, while still ensuring adoption of
programs that satisfy all mmimum '
requirements of the final Guidance. EPA
invites comments on all aspects of this
approach and any other alternative
approaches, including whether the final
' Guidance should require verbatim
adoption of all elements.
In §§ l32.5(e)(l) and 132.5(e)(2) EPA
is proposing specific provisions .•'•'•
• concerning how EPA will determine :;
that State or Tribal numeric criteria and ;
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Federal Register / Vol. 58, No. 72 / Friday. April 16, 1993 / Proposed Rules
interpretation of narrative criteria are
consistent with the final Guidance. The
provisions operate differently
depending on which pollutants are
involved, and whether the State or Tribe
has adopted numeric criteria for the
pollutant.
For pollutants listed in Tables 1,2,3
and 4, EPA will determine that the
submission is consistent with part 132
if the Great Lakes State or Tribe has
adopted criteria corresponding to each
of tho criteria listed to Tables 1 through
4, and the State or Tribal criteria are
equal to or more restrictive than each of
tho criteria in the Tables. If the State or
Tribe has applied site-specific criteria
modifications, they will need to
demonstrate that the site-specific
criteria modification procedures of
appendix F were used, or if other
procedures were used, such other
procedures produce site-specific criteria
equal to or more restrictive than criteria
developed through application of
appendix F procedures.
For pollutants other than those listed
in Tables 1,2,3 and 4, the requirements
of § 132,5(e}(2) are Intended to ensure
that State or Tribal criteria
mathodologies and narrative
Implementation procedures result hi
criteria or values equal to or more
restrictive than tho proposed Guidance
methodology produces.
—If the Great Lakes State or Tribe has
adopted numeric criteria for the
pollutant in its water quality
standards, then the State or Tribe
must demonstrate that it either used
the appropriate methodology
specified in the final Guidance, or,
using a different methodology,
obtained criteria equal to or more
restrictive than the Guidance's
methodology would produce. If the
numeric criteria were adopted into
State or Tribal water quality standards
prior to the date of final publication
of this part, §132.5(e)(2Kii) provides
that the Great Lakes State or Tribe
may alternatively choose to
demonstrate to EPA that it has
adopted a procedure by which the
State or Tribe will use Guidance-
based criteria and values, instead of
the numeric criteria adopted in its
standards, when it develops water
quality-based effluent limits and total
maximum daily loads if the Guidance-
based criteria and values are more
rflstrictlva than the adopted criteria.
Tho reason for including this
alternative demonstration is to give
States or Tribes the administrative
flexibility to determine the adequacy
of such criteria at a later date—that is,
the timo when water quality-based
effluent limits or total maximum daily
loads are developed—rather than the
time of the submission required by
§ 132.5. This may be a reasonable
alternative for States that have
adopted a large number of numeric
criteria into their water quality
standards and are unable to review all
criteria for consistency with this part
in time for the submission required by
§ 132.5. To'implement such an
alternative procedure, the State will
need to demonstrate that it has in
place the regulatory mechanisms to
ensure that the State will apply the
methodologies in the final Guidance
to develop water quality-based
effluent limits and total maximum.
daily loads if existing State numeric
water quality criteria would result in
less restrictive effluent limitations.
—If the Great Lakes State or Tribe has
not adopted numeric criteria for the
pollutant in its water quality
standards, then the State or Tribe -,
must demonstrate that it has adopted
a procedure by which water quality-
based effluent limits and total
maximum daily loads will be
developed using water quality criteria
and values derived pursuant to the
Guidance Tier I and Tier n
methodologies required by § I32.4(c).
EPA believes that the requirements of
§ 132.5(e) are appropriate to ensure a
minimum level of consistency in
implementation'of the Guidance
throughout the Great Lakes System in
accordance with the legislative intent of
the Great Lakes Critical Programs Act
(see section H.E of this preamble). EPA
invites comment on all aspects of these
requirements.
/. Precedential Effect of Elements of the
Guidance
The requirements in the proposed
Guidance are expressly applicable only
to the waters of the Great Lakes System.
However, the proposed Guidance
addresses many central elements of
existing National and State water
quality programs. For example, all
States currently have regulations and/or
guidance addressing methodologies to
derive and implement water quality
criteria and antidegradation policies,
and procedures for determining TMDLs
for specific water bodies. Although
some elements of the proposed
Guidance incorporate data or
considerations specific to the Great
Lakes System, EPA believes that many
portions might be beneficially applied
in other jurisdictions.
EPA is not proposing nationwide
application of any portions of the
proposed Guidance because section
118(c){2) of the Clean Water Act is
limited to promulgation of Guidance for
the Great Lakes System. EPA does
request comment, however, on whether
EPA should issue National guidance or
propose any modifications to 40 CFR
parts 122-124,130 and 131 in the future
to correspond with specific elements of
today's proposed rule.
K. Endangered Species Act ,
Section 7(a)(2) of the Endangered
Species Act (ESA) requires each Federal
agency, in consultation with the U.S.
Fish and Wildlife Service (FWS), or the
National Marine Fisheries Service for
species under its jurisdiction, to ensure
that actions authorized, funded or
carried out by the Federal agency are
not likely to jeopardize the continued
existence of any endangered or
threatened species listed under the ESA,
or result in the destruction or adverse
modification of such species' critical
habitat (i.e., are not likely to "cause
jeopardy"). EPA has initiated informal
consultation with the FWS to insure
that implementation of part 132 by EPA,
States and Tribes is not likely to cause
jeopardy for species in the Great Lakes
System. While EPA has not determined
that consultation is required for all
aspects of the proposed Guidance at this
Stage, consultation on the proposed
Guidance will help insure that
submissions by the Great Lakes States '
and Tribes under part 132 will provide
for adequate protection of endangered
and threatened species, and thereby
help avoid delays in EPA's approval of
such submissions. EPA will consider
the results of our consultation with the
FWS, along with all public comments
on today's proposal, in determining
appropriate requirements for
endangered or threatened species in the
final Guidance.
As a result of the consultation, EPA
may determine that provisions should
be included in the final Guidance
specifically targeted to ensuring the
protection of endangered or threatened
species. For example, one approach
would be to require in § 132.5 of the
proposed Guidance that any submission
by a Great Lakes State or Tribe include
provisions to ensure that the
development and implementation of
criteria, methodologies, policies arid
procedures under part 132 are not likely
to cause jeopardy. Such a provision hi *
the final Guidance would authorize EPA
to disapprove a submission by a State or
a Tribe that did not ensure that jeopardy
of endangered or threatened species ,
would be avoided, or to require a State
or Tribe to include measures or
alternatives recommended by the FWS
to reduce impacts to endangered and
threatened species.
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20849
In addition, EPA could adopt in the •
final Guidance specific.text that States
arid Tribes would need to include in
•their submissions in .order to ensure
adequate protection of endangered and
threatened species. Regarding
implementation procedures, the
Guidance could, for example, require
that States and Tribes include '.
provisions stating that mixing zones and
variances will not be permitted to the
extent they will likely cause jeopardy of
endangered and threatened species.
Similarly, the final Guidance could
require that antidegradation policies
submitted for,EPA approval include a
requirement that water quality be
maintained at a level necessary to insure
that endangered or threatened species
are not likely to be jeopardized due to
water quality conditions. EPA solicits
suggestions of text that EPA could
include in the final Guidance to ensure/
•that implementation procedures and
other relevant aspects of the proposed
Guidance willprovide for protection of
endangered and threatened species.
With regard to water qualitjr criteria,
EPA expects to consult on the aquatic
life and wildlife water quality'criteria '
and methodologies in the proposed
Guidance. To the extent these criteria
and methodologies are determined in
this consultation to be protective of
endangered and threatened species in
the Great Lakes System, adoption of
these provisions by States and Tribes
would be approvable by EPA. If these
criteria and methodologies are
determined not to be protective of
certain species in the Great Lakes
System, EPA is considering including
text requiring that States and Tribes
adopt adequately protective site-specific
criteria. If a State or Tribe adopts site-
specific modifications to aquatic life
criteria under section A.l.a of procedure
I of appendix F to part 132, the State
. or Tribe will need to ensure that those '
modifications will provide adequate
protection of endangered,or threatened
species. In addition, EPA is considering
the option of requiring States and Tribes
to modify aquatic life and wildlife
criteria/values on a site-specific basis to
. provide protection appropriate for
endangered and threatened species, and
EPA soli cits public comments on such
ail approach.
- By consulting with the FWS under
section 7 of the ESA on the proposed
Guidance, EPA is seeking to carry out its
responsibilities under the CWA in a
manner that also helps achieve the
objectives of the ESA. Obviously, the
two statutes promote similar goals,
because improving water quality can
have beneficial effects on the viability of
endangered or threatened aquatic life :
and wildlife. EPA believes that EPA,
States and Tribes should pay particular
attention to preventing water quality
degradation where it would have:
detrimental effects on endangered and
threatened species. If EPA were to
include provisions addressing
endangered and threatened species in
.the Guidance, however, EPA would not
be seeking to impose any procedural
obligation on Great Lakes States and
Tribes to consult with the FWS under
section 7(a)(2) of the ESA. The section
7 consultation provisions apply only to
Federal agencies (although Federal
agencies can in certain cases designate
non-Federal representatives for
purposes" of informal consultation).
Rather, EPA would be explicitly
addressing the need for protecting
endangered and threatened species in
order to insure that promulgation of the
Guidance and approvals of submissions
by Great Lakes States and Tribes are
consistent with the no jeopard}'
standard in section 7(a)(2) of the ESA.
L. Request for Comments
• EPA has received and placed in the'
public docket materials submitted
during the public proceedings on the
Great Lakes Water Quality Initiative.
EPA considered these comments in the
development of the proposed Guidance.
Because these materials contain
comments on draft provisions that have
been superseded by the proposed
Guidance and EPA would have
difficulty identifying portions that
remain relevant to this proposal, EPA
will not consider them in the
development of the final Guidance. , .
Additionally, EPA believes that the time
available for promulgation of the final
Guidance can be used most efficiently
and effectively by addressing those
issues that have not already come before
EPA. Accordingly, EPA advises the .
public that for the purposes of ,
exhaustion of administrative remedies,
new comments must be submitted based,
on the proposed Guidance.
EPA requests comment on each
element of the proposed Guidance,
including all subjects and issues raised
in the preamble discussion whether or
not specific regulatory text has been
provided in the proposed Guidance, and
any suggested alternative requirements
or, combinations of requirements to
address these elements and issues in the
final Guidance. EPA may promulgate
final rules based on any of the issues or
subjects discussed in the proposed
Guidance, or based on combination of
possible requirements to address these
subjects and issues. EPA expects to
finalize requirements in the final .
Guidance addressing these subjects and
issues based upon the discussion in the
, preamble and evaluation of all;
submitted comments. EPA will not
make any-final decisions on any
element or issue of the final Guidance
until after full consideration of the -'
public comments.
in. Aquatic Life
A. Introduction and Purpose
EPA has broad authority to develop
criteria to protect aquatic life in Great
Lakes waters, Section 304(a)(l) of the
Clean Water Act generally authorizes
EPA to develop criteria to protect
aquatic life in all waters of the United
States. Section 118(c)(2)(A) of the Clean
Water Act requires EPA to develop
specific numeric criteria to protect
aquatic life in the Great Lakes. This
requirement implements portions of the
Great Lakes Water Quality Agreement of
1978 (Agreement). One of the
Agreement's "General Objectives" is
freeing the Great Lakes System from
substances resulting from human
activity that will adversely affect aquatic
life. Several of the "Specific Objectives"
for individual pollutants set out in
Annex 1 of the Agreement are also
specifically directed at the protection of
aquatic life. Moreover, both the .
legislative history to section 118(c) and
the text of the Agreement emphasize the
goal of more consistent water quality
criteria across the Great Lakes.
. Observed effects on aquatic life, such
as population declines and abnormal .
reproduction, provide clear evidence ;
that the goals of the Clean Water Act
and the objectives of the Great Lakes
Water Quality Agreement for aquatic life
are not being met throughout the Great
Lakes System (Sixth Biennial Report on
Great Lakes Water Quality, April, 1992).
This report is available in the
administrative record for this
rulemaking. To improve water quality
and to promote more consistent
protection of aquatic life within the
Great Lakes System, EPA is proposing a
new approach to developing aquatic life
criteria for the Great Lakes. Some of the
criteria in the proposed Guidance are
more restrictive than the nationally
applicable criteria EPA has published
under Clean Water Act section 304(a).
Further, EPA is proposing to promote
consistency by requiring Great Lakes
States and Tribes to adopt specific
criteria at least as stringent as those
proposed herein and specific ,
methodologies identical to or more
stringent than those proposed herein. As
explained in more detail below, EPA
believes that the proposed criteria for
aquatic life and the requirements for
implementing them will conform with
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20850 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
tho objectives of the Great Lakes Water
Quality Agreement and be "no less
restrictive" than National water quality
criteria and guidance.
As described below, EPA is proposing
Great Lakes Water Quality Guidance for
Aquatic Life which contains two tiers,
subsequently referred to as Tiers I and
n. This tiered approach allows Great
Lakes States and Tribes to provide more
consistent protection of aquatic life from
tha discharge of pollutants, even if
information on the pollutant's effects is
too limited to meet the strict data
requirements in tho proposed Guidance
for setting aquatic life criteria under
Tierl.
The Aquatic Life Tier I methodology
is similar to "Guidelines for Deriving
Numerical National Water Quality
Criteria for the Protection of Aquatic
Organisms and Their Uses" (Stephen, et
ol,, 1985), which is the current National
guidance for developing aquatic life
criteria. A copy of the 1985 National
Guidelines is available in the
administrative record for this
rulomaking. Copies are also available
upon written request to the person
listed in section XIII of this preamble.
Tho 1985 National Guidelines can also
bo obtained through the National
Technical Information Service (PB 85-
227049). The Tier I methodology is to be
used in deriving Great Lakes Aquatic
Lifo Criteria for use in State and Tribal
Water Quality Standards. The Tier I
criteria are based on the latest scientific
knowledge and are derived using an
is "a new tool" for regulating discharges
within the Great Lakes System when
sufficient data do not exist to derive a
Tier I criterion. While similar concepts
hava been employed by individual
States within the Great Lakes System,
this Tier n methodology will provide a
consistent approach for all Great Lakes
States and Tribes. This methodology
utilizes limited lexicological data to
derive conservative regulatory values for
individual pollutants. The Tier n
methodology will be used in
conjunction with the proposed whole
effluent toxicity requirements, in
interpreting the State's narrative criteria
(e.g., no toxic pollutants shall exist in
toxic amounts). Tier n values can serve
as the basis for some regulatory
decisions, such as permit limitations.
Although the State or Tribe will have
authority to adopt Tier n values as
standards, it is not intended that Tier n
values will normally be adopted as State
water quality standards. Rather, EPA
believes it is more desirable for the
regulatory agencies and/or dischargers
to continue to supplement data on
pollutants to the point where a Tier I
criterion can be calculated and
subsequently adopted as a criterion for
use in State and Tribal water quality
standards.
B. Tier I Criteria
1. Methodology
The Committees of the Initiative
chose, as the starting point for the
development of the Aquatic Life Tier I
methodology, EPA's "Guidelines for
Deriving Numerical National Water
Quality Criteria for the Protection of
Aquatic Organisms and Their Uses"
(1985 National Guidelines) as cited in
SO FR 30784 (July 29,1985) and
developed under section 304(a) of the
Clean Water Act.
The 1985 National Guidelines contain
provisions for deriving both freshwater
and saltwater criteria. As the Great
Lakes System is composed entirely of
fresh water, those portions of the 1985,
National Guidelines which pertain to
fresh water serve as the basis for the
Tiejr I aquatic life methodology in the
proposed Great Lakes Water Quality
Guidance. Since the Great Lakes Tier I
methodology closely resembles the 1985
National Guidelines, the following
•narrative is a discussion of the 1985
National Guidelines and the specific
changes made to it in the proposed
Guidance for Tier I aquatic life
methodology.
The proposed Great Lakes Guidance,
like the 1985 National Guidelines,
results in the derivation of two criteria
concentrations to protect aquatic life for
any given pollutant. The first of these,
the Criterion Maximum Concentration
(CMC), is designed to protect aquatic
life from effects of short term or acute
exposures. The second, the Criterion
Continuous Concentration (CCC), is
designed to protect against effects to
aquatic life due to long term or chronic
exposure. In order to derive a CMC for
a pollutant, it is necessary that
acceptable acute toxicity studies exist
for aquatic animal species in at least
eight families which represent differing
habitats and taxonomic groups. These
eight families are intended to represent
a wide spectrum of aquatic animals. The
Great Lakes aquatic life methodologies
provide guidance on determining data
acceptability.
Results of acute toxicity studies are
expressed in terms of ECSOs or LCSOs.
An EC50 is the concentration which
will cause an adverse effect to 50
percent of the exposed individuals (e.g.
immobility, possibly including death)
within a given period of time (typically
48 hours for daphnids and other
cladocerans, and 96 hours for other
aquatic animals). An LC50 is the
concentration oif a pollutant which will
cause the death of 50 percent of the
exposed individuals within these same
lime frames. EPA is proposing to follow,
the approach established in the 1985
National .Guidelines for deriving a Final
Acute Value (FAV) to protect a broad
range of aquatic species by ranking th e
Genus Mean Acute Values (geometric
means of the Species Mean Acute
Values for. each genus), and then
interpolating or extrapolating to
estimate the acute value for 95 percent
of the genera tested. As described in the
1985 National Guidelines, the FAV must
be set equal to the lower of the 95th
percentile value, or the Species Mean
Acute Value for a species of commercial
or recreational importance (the Tier I
methodology differs from the 1985
National Guidelines by specifying that
the FAV should only be lowered for a '
species that is recreationally or
commercially important to ,the Great
Lakes System). The CMC is equal to
one-half the FAV. The FAV is divided
by two to convert a concentration toxic
to 50 percent of the individuals of the
tested species, to a concehtration'not
acutely toxic for nearly all individuals
of the species.
EPA believes that the proposed
methodology provides a broad base of
protection for the aquatic life of the
entire Great Lakes System. There are
documents for the sixteen proposed Tier
I criteria, within the Administrative
Record, which contain detailed
information on the range of species
tested.
The Technical Work Group
considered inserting a provision in the
Great Lakes Tier I procedure that would
also allow the lowering of the FAV to
protect "ecologically important" species
of the Great Lakes. However, it was felt
that it would be unnecessary given the
scope and protective nature of the
proposed Guidance to single out
particular species for additional
protection on the basis of "ecological
importance", because the method
generally provides protection for the
entire ecosystem. Furthermore, the
Technical Work Group could not reach
consensus on identifying any individual
species as "ecologically important" or
defining the term "ecologically
important". Therefore, the proposed
Guidance does not include provisions
for lowering an FAV for "ecologically
important" species. This is consistent
with the 1985 National Guidelines. EPA
invites comment on this issue, and
particularly on the issues of how to
define "ecologically important'' species
for the Great Lakes, and whether or not
such "ecologically important" species * "
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Federal Register /Vol. 58, No. 7g 7 Friday, April 16, 1993 / Proposed Rules
20851
! adequately protected by the
>posed guidance.
are (
proposed guid_...__..
•EPA is proposing slightly greater
modifications to-the 1985 National
Guidelines' approach to chronic
exposures. In the 1985 National
Guidelines, the CCC is the lowest of the
Final Chronic Value (FCV), the Final
Plant Value (FPV) or the Final Residue
Value (FRV). The reason the 1985
National Guidelines set the CCC as the
lowest of the FCV, FPV, or the FRV is
to provide protection for aquatic plants,
wildlife and the marketability of
commercially-important aquatic species,
as well as other aquatic animals. As
explained in more detail below, EPA is
proposing to retain the options of using
either a FCV or a FPV to determine the
CCC, but proposing to delete the option
of using FRVs.
EPA. is proposing to follow the
approach established in the 1985 .
National Guidelines by allowing the
FCV to be calculated in one of two
ways. If acceptable chronic toxicity
studies (i.e., studies which span a
significant portion of the life cycle of
the tested species and which measure
endpoints such as growth and .
reproduction) exist for the required
eight families of aquatic animals (which
represent differing habitats and
taxonomic groups), then the FCV can be
calculated using the same mathematical
procedure as was used in tie derivation
. of the FAV. If acceptable chronic
toxicity studies do not exist for the eight
families, the FCV must be set equal to
the lower of the quotient of the FAV
divided by the Final Acute-Chronic
Ratio (ACR). The Acute-Chronic Ratio
(ACR) is a way of relating acute and
chronic toxicities. To'derive an ACR,
, comparable acute and chronic toxicity
studies have been conducted 'under
similar conditions for a given species.
From comparable measurements of
acute .and chronic values, an ACR is
calculated by dividing the measured
acute value by the measured chronic
value. EPA is proposing to follow the
1985 National Guidelines by requiring
ACRs for at least three families of
aquatic animals. The Final Acute-,
Chronic Ratio (FACR) must be either the
geometric mean of some or all. of the.
species ACRs or another value
appropriate for sensitive species.
The 1985 National Guidelines allow
the use of ACRs for saltwater species in
the derivation of the FCV for freshwater
animals. Because the Great Lakes are
freshwater lakes, the proposed Great
Lakes Guidance, while still-allowing for
the use of saltwater ACRs, expresses a
preference for the use of freshwater
ACRs. EPA invites comment on the
preference for freshwater acute-chronic
ratios in calculating a Final Chronic
Value to protect species within the
Great Lakes System.
AS with the PAV, the Great Lakes
Guidance provides for the lowering of
the FCV, where necessary, to protect a
commercially or recreationally
important species within the Great
Lakes System. However, similar to the
earlier discussion pertaining to FAVs,
the Guidance does not include an
.option of lowering the FCV for
"ecologically important" species. EPA...
invites comment on this issue.
A plant value is the result of a 96-
hour test conducted with an alga, or a
chronic test conducted with an aquatic
vascular plant. The FPV is obtained by
selecting the lowest result from a test
with an important aquatic plant species,
in which the endpoint was biologically
important (e.g.; survival) and the test
concentrations were measured. EPA is
proposing to, retain the provision of
setting the CCC equal to the lower of the
FCV or the FPV, as in the 1985 National
Guidelines.
the 1985 National Guidelines "
indicate that the FRV is intended to :
prevent concentrations of pollutants in
commercial or recreational aquatic
species from affecting the marketability
of those species or affecting wildlife that
consume aquatic life. By preventing the
exceedance of applicable FDA action
levels (concentrations of pollutants set
by FDA as acceptable amounts in ..
marketable fish tissues for human
consumption), marketability of those
species can be maintained. The FRV is
also intended to protect wildlife,
including mammals and birds, that
consume aquatic organisms.
The proposed Great Lakes Guidance
does not include provisions for
calculating a FCV on the basis of a FRV,
as specified in the 1985 National
Guidelines. (This change, in part, results
in criteria which are different from
published National aquatic life criteria
which are based on a FRV, e.g., dieldrin,
endrin, and mercury.) There are several
reasons for this change.
First, a separate methodology for
deriving criteria for the protection of
wildlife is being proposed under a
.separate portion of the Guidance, '
whereas no such guidance currently
exists on the National level. The FRV is
currently utilized to provide protection
to wildlife within the 1985 National
Guidelines for the protection of aquatic
life; EPA believes that the'wildlife
criteria proposed in the proposed
Guidance will be derived hi a manner
that would yield more appropriate
criteria to protect wildlife than the FRV.
More detailed information 'on the
wildlife criteria in the proposed ; :
Guidance may be found hi section VI
below. Thus, for the purposes of the.'(-.
Great Lakes System, provision for a CCC
based on impacts to wildlife would be
dupUcative and less Great Lakes-
specific.; EPA invites comment on this
issue, and particularly oh whether it is
necessary to have provisions, within the
aquatic life guidance, to ensure
protection of wildlife, rather than
having a separate methodology directed
at- protection of wildlife.
Further, EPA believes that the
assumptions which are made hi'the
development of an FDA action level, '
, and particularly the fact that those .
action levels are based upon National
fish consumption values, makes the
application of these action levels
inappropriate for use in the proposed
Guidance. Rather, EPA believes that the
derivation of criteria for the protection
of human health within the Great Lakes
System more appropriately takes this
consideration into account with Great
Lakes fish consumption values. '
Therefore, EPA believes that the human
: health methodologies being proposed
elsewhere in this notice will provide an
appropriate level of protection to
humans consuming Great Lakes fish.
More detailed information on the
human health criteria proposed may be
found in section V below. Again, given
the human health criteria proposal, EPA
believes that for the purposes of the
Great Lakes, provision for usage of FDA
action levels would be dupUcative and
less Great Lakes-specific. Thus, the
proposed Guidance only provides for
the derivation of a CCC based either on
a FGV or a FPV. EPA invites comment
on this issue, and particularly on the
issue of deleting the use of a FRV.
In its December 16,1992, report,
"Evaluation of the Guidance for the
Great Lakes Water Quality Initiative,"
the EPA's Science Advisory Board
- (SAB) recommended that EPA: consider
both the biologically active form and the
total contaminant concentrations of a
pollutant when establishing water
quality criteria, This report is available
.in the administrative record for this
rulemaking. Within the Tier I
methodology, section I.A.3 of appendix
A to part 132, the State or Tribe is given
guidance in determining for what form
of the pollutant to derive the criterion.
The State or Tribe is given guidance in
determining ah operational analytical
component to the criterion that
describes the analytical method that is "
intended. The methodology itself does,
not specify a particular analytical
method that must be used. The
analytical method chosen must
accurately reflect the form of pollutant
for which the criterion is derived. The
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20852 Federal Register / Vol. 58, No. 72 7 Friday^ April 16, 1993 / Proposed Rules
criteria documents for 9 of the 16
pollutants for which Tier I criteria are
Doing proposed in the proposed
Guidance identify an analytical
methodology that should he used. The
State or Tribe has the flexibility to
choose the most appropriate analytical
method. The State could choose, for
example, to derive a criterion for the
bioavailablo form, or for the total
contaminant concentration. Although
criteria developed using the Tier I
method in the proposed Guidance may
not consider both the biologically active
and total contaminant concentration, a
mechanism within the site-specific
criteria modification procedure,
procedure 1 of appendix F to part 132
may be used to address this concern.
Because the bioavailability of a
pollutant is linked to the water
chemistry within a specific receiving
water or effluent, EPA believes the
water-effect ratio approach, as described
in the 1983 Standards Handbook,
Chapter 4 and as modified by the 1992
Interim Guidance on Interpretation and
Implementation of Aquatic Life Criteria
for Metals, which is available in the
administrative record of this
rulomaking, is the appropriate
mechanism to address bioavailable
versus total concentrations of
contaminants. The water-effect ratio
approach is a biological method which
compares bioavailability and toxicity of
a contaminant in receiving waters
versus laboratory test waters. EPA
invites comment on whether
bioavailability of contaminants is
adequately addressed using site-specific
modification approaches, as well as
alternatives to address the issue of
expressing toxicity of both bioavailable
and total contaminant concentrations.
The 1985 "Guidelines for Deriving
Numerical National Water Quality
Criteria for the Protection of Aquatic
Organisms and Their Uses" (1985
National Guidelines) have previously
undergone scientific peer review and
public review and comment, and have
boon revised as appropriate. Therefore,
for those portions of the Tier I aquatic
life methodology that are the same as
the 1985 National Guidelines, EPA does
not intend to address the issues already
addressed by EPA in response to
previous comments in this proposed
rulemaking.
2. Selection of Pollutants for
Application of Tier I Criteria
Methodology
Tho Groat Lakes Water Quality
Guidance specifies o number of numeric
limits on pollutants in ambient Great
Lakes waters to protect aquatic life,
along with the methodology used in
calculating criteria. To begin the process
of developing criteria and to evaluate
the proposed methodologies, the
Initiative Committees selected 26
pollutants for which there are current
National water quality criteria for the
protection of aquatic life and which are
included in Table 6 to derive Tier I
aquatic life criteria (see list of 26
pollutants in the Administrative
Record). Of these 26 pollutants, EPA is
proposing, in the proposed Guidance,
numeric (Tier I) criteria for 16. EPA is
proposing numeric criteria derived
using the proposed Tier I Aquatic Life
methodology for an additional pollutant
for which there is currently not a
National criterion (phenol). EPA has
derived draft National criteria for
phenol, which are currently undergoing
EPA review and will be proposed hi the
Federal Register as draft National Clean
Water Act section 304(a) criteria, once.
that review is complete.
The reasons EPA is not proposing Tier
I criteria for the other nine pollutants
are set forth below. First, some of the
National aquatic life criteria were
developed before 1985, under a ,
methodology different from the 1985
National Guidelines. The earlier
methodology did not have the same
minimum data requirements as the
current Tier I methodology or,the 1985
National Guidelines. The data used to
determine the 1980 criteria for aldrin,
chlordane, DDT, endosulfan,
heptachlor, lindane, and PQBs, while
adequate under the earlier methodology,
do not meet the minimum data ,
requirements established in the 1985
National Guidelines. (Data were not
sufficient to calculate a chronic Tier I
criterion for lindane; however, there ,
was a sufficient data set to calculate an
acute Tier I criterion.) Therefore, these
pollutants do not meet the minimum
data requirements needed to derive Tier
I aquatic life criteria even though there
are existing National criteria for them.
Further, there are three pollutants that
were developed under the 1985
National Guidelines for which the
Agency made exceptions to its
minimum data requirements. The
National aquatic life criteria for lead
("Ambient Water Quality Criteria for
Lead—1984"), toxaphene ("Ambient
Water Qualify Criteria for Toxaphene—
1986") and chlorpyrifos ("Ambient
Water Quality Criteria for
Chlorpyrifos—1986") have data for only
seven of the eight families required.
EPA believes that the National criteria
for these pollutants would not be
significantly different with the addition
of the eighth data point. However, the
Initiative Committees proposed to
follow the Tier I methodology, as
written. In addition, the Tier n
methodology allows for the missing data
to be provided or developed by the
regulatory agency or permittee.
Therefore, Tier I aquatic life criteria
were not calculated for lead, toxaphene,
and chlorpyrifos. The Steering
Committee believed that the Tier II
methodology should be used for all
pollutants of initial focus in the Great
Lakes Water Quality Initiative (i.e.,
pollutants in Table 6) which do not
meet the data requirements in the Tier
I methodology. EPA notes that it.
continues to believe that the decision to
allow exceptions to the database
requirements for these three pollutants
was reasonable for the National criteria,
since EPA has not developed any
procedure resembling Tier n that could
be used as a "fallback" on the National -
level.
EPA is proposing to follow the
Steering Committee's proposals not to
promulgate, at this time, specific
numeric criteria for these nine
pollutants. EPA requests comment on
the alternative proposal of requiring
States and Tribes to adopt the current
National criteria for these pollutants,
even though these National criteria are
based on methods developed before
1985 or on less than the minimum data
requirements for the 1985 method. The
fact that criteria for these specific
pollutants are not being proposed in the
proposed Guidance does not mean that
criteria cannot, or will not, be
developed in the future. Moreover, the
States and Tribes will be able to regulate
these pollutants using the proposed Tier
H methodology before any criteria are
developed.
Aquatic data exists to derive aquatic'
life criteria for aluminum. However, due
to time and resource limitations, aquatic
life criteria for aluminum could not be
derived. As proposed, this Guidance
would leave the derivation of aquatic
life criteria for aluminum to the States.
EPA requests comment on this approach
and alternatively whether EPA itself
should derive aquatic life criteria for
aluminum.
3. Tier I Numeric Criteria
Table IE—1 presents CMCs, or acute
criteria, calculated using the proposed
Tier I methodology for aquatic life. For
comparison, the CMCs of existing
National criteria are also included.
Differences between National and Great
Lakes Tier I acute and chronic criteria
can be attributed to one or more of three
reasons. . . •
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Federal Register 7 Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
20853
TABLE 111-1 .—Acute AMBIENT WATER
QUALITY CRITERIA FOR AQUATJC LIFE
Chemical . -
Arsenic (111) ..s:
Cadmium b ' .-
Chromium (III)" ....
Chromium (VI) .........;
CODD6fb ................ ,i..
Cyanide free ;....
Dieldrin .....
Mercury (!l)
Nickel b .,......;.
Parathion
Pentach!orophenolc .
Phenol
Total Selenium
Zinc" ........
Great
Lakes
CMC*
340
2.1
1000
16
7.3
, 22
0.24
0.09
0.95
0.83
260
.065
5.3
3700
20
67
National
CMC*
360
1.8
980
16
9.2
22
"2.5
"0.18 •
d2.0
2.4
790 '
.065
5.5
20
65
"All values are in fig/L. , '
bThe toxicity of ttiis chemical is hardness
related; the criterion expressed is at a
hardness of 50 mg/L " ,
"cThe criterion for this chemical is pH
dependent; the criterion expressed is at a pH
Of 6.5. •- - .". '
• "This value is an FAV that was calculated
-according to the ,1980'guidelines. Although the
CMC = FAV/2 in 'the 1985 National
Guidelines, there is no CMC in the 1980
guidelines and the procedure used to derive
the FAV is different from that used in the 1985
National Guidelines/ .-• /
'• First, the existing National criteria
•were derived between 1980 and 1987.
Some .of the criteria derived using the
Great Lakes Guidance were calculated
using data, published subsequent to
individual National,criteria documents, .
Those chemicals for which this applies
are: cadmium, chromium, copper,
dieldrin, endrin, lindane; mercury,
nickel, selenium, silver, and zinc. The
development of an updated database
resulted in less restrictive acute and/or
chronic criteria for cadmium, chromium
HI, and zinc as compared to National
criteria. However, EPA believes that, the
differences between the proposed Great
Lakes criteria and the National criteria'
are insignificant. Furthermore, it is
EPA's position that usage of the Great
Lakes criteria is more appropriate than
the National.criteria because they are
. based on more recent data. EPA,
however, requests comment on the
option of promulgating the National
.criteria values.for those pollutants
which have more stringent National
criteria values.
Secondly, ,as mentioned earlier, some
.of the National criteria were derived
using a methodology which preceded
the 1985 National Guidelines. Where
sufficient data existed, the committees
•recalculated the criteria, tobe^consistent
with the methodology being proposed.
Those chemicals for which this applies
are: Dieldrin, endrin,'and ^
hexachlorocyclohexane (lindane).
" (chronic criteria only). None of these '
proposed criteria, however, are less
restrictive than the current National •
criteria. •
Third, some corrections were required
in some of the National criteria -•
documents. Some of the data used in •
deriving the National criteria were.
deleted because they were not.
considered acceptable under the current
toxicity testing protocol described in
sections n, HI, IV, V, VI, and VH of the
proposed Great Lakes methodology for
Tier I aquatic life criteria (appendix A
to part 132). The pollutants for which
this applies are copper, dieldrin and
endrin. None of these changes produced
criteria that are less restrictive than the
National criteria.
A technical support document, "Great
Lakes Water Quality Initiative Water
Quality Criteria for Protection of
Aquatic Life in Ambient Water, Criteria
Documents," discusses the derivation of
each of the Tier I acute criteria and the
toxicity studies from which the criteria
were derived are available in the
administrative record for this
rulemaking. The proposed Guidance
> would require that the numeric criteria
in Table 1 to part 132 be adopted by the
Great Lakes States and Tribes and
incorporated into their ambient water
quality standards. The specific
requirements on how these criteria are.
to be incorporated into State and Tribal
water quality standards are discussed in ...
section II of this preamble.
Table HI—2 presents CCGs, or chronic .
criteria, calculated using the proposed '
Tier I methodology for aquatic life. For
•comparison, the CCCs of existing
National criteria are also included. In
addition to the reasons cited earlier
concerning differences between
National and Great Lakes CMCs, several
of the Great Lakes CCCs are affected by,
the preference of using freshwater ,
ACRs, ; '
TABLE 111-2.—-CHRONIC AMBIENT WATER
QUALITY CRITERIA FOR AQUATIC LIFE
TABLE 111-2.—CHRONIC AMBIENT-"WATER
QUALITY ^CRITERIA FOR AQUATIC LIFE—
Continued : .
Chemical
Penta- ".•'-' ,
chlorophenolc ...
Phenol ..,
Total Selenium .....
Zinc".
Great
Lakes
CCC"
3.3-
, 120
5.0
60 ,
National
CCC*
3.5
5.0
59
Chemical .
Arsenic (III) .....
Cadmiurhb .............
Chromium (111)" :...
Chromium (Vl)
Copper b .:.;;....:
Cyanidei free.........
Dieldrin ............
Endrin ........
Mercury (11) •;-.
Nickel b ..........
Parathion ..:......
Great
Lakes
CCC"
150
• 0.78
49
11 '
5.2
5.2
0.056
. 0.037
0.44
29
0.013
National ,
CCC»
190
0.66
• .120
11
6.5
5.2
"0.0019
d 0.0023
d0.012
88
0.013
•All values in
bThe toxicity of this chemical is hardness
related; the ~ criterion expressed is at a
hardness of 50 rhg/L.
"The toxicity ofthis chemical is pH related;
tie criterion expressed is at a pH of 6.5.
d Based upon Final. Residue value.
The derivation of each of these
chronic criteria, and the toxicity studies
upon which they are based, are also
discussed in "Great:Lakes Water Quality
Initiative Water Quality Criteria for
Protection of Aquatic Life in Ambient
Water, Criteria Documents." This
document is available in the
administrative: record for this.
rulemaking. The proposed Guidance
would require that the numeric criteria
in Table 2 to part 132 be adopted by the
Great Lakes States and Tribes and
incorporated into their ambient water
quality standards. The specific
requirements oh how these criteria are •
to be incorporated into State and Tribal
water quality standards are discussed in
section n of this preamble.
1. Potential Changes to National
Guidelines
EPA periodically reviews and updates
the methodology which is used to
derive National aquatic life criteria to .
accurately reflect the latest scientific ':.
knowledge. Currently, an EPA work
group is reviewing "Guidelines for ,
Deriving Numerical National Water-
Quality Criteria for the Protection of
Aquatic Organisms and Their Uses" „
(1985 National Guidelines). EPA may
propose changes to the 1985 National
Guidelines in 1993: Within the 1993
proposal, EPA may choose to
incorporate some or all of those changes
into the Great Lakes Tier I methodology,
as "described in the proposed Guidance.
EPA advises all'persons with an interest
in the Tier I criteria to watch for .the ' •
proposal on revisions to the 1985
National Guidelines.
C. Tier II Values ,\ .
The Initiative Committees struggled
with how to regulate pollutants for
which an extensive data base, as
required for the Tier Imethodology and
the 1985 National Guidelines', does not
exist. In many cases, States and Tribes
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20854
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
need to regulate discharges for which a
full complement of aquatic toxicity data
is not available for a particular
pollutant. Some of the Great Lakes
States and Tribes, such as Ohio and
Michigan, currently have procedures
that are intended for USB as translator
mechanisms for narrative criteria (e.g.,
no toxic substances in toxic amounts).
The Steering Committee wanted to
ensure consistency among States and
Tribes in using limited data to derive
values for regulating discharges in the
Great Lakes System, The Steering
Committee also wanted to develop a
methodology to be used as a translator
mechanism common to all Great Lakes
States and Tribes that could be used in
sotting permit limits for the Great Lakes
System. This approach is consistent
with the goals and purposes of the Great
Lakes Critical Programs Act of 1990.
Also, as explained in section K of the
preamble, EPA wanted to give
dischargers an incentive to conduct
studies and develop data that would
permit EPA to promulgate Tier I criteria
for additional pollutants.
To address the needs referenced
above, the Steering Committee
developed a Tier II methodology under
which aquatic lifa values could be
calculated with fewer than the eight
taxonomic families of data required for
a Tier I criterion calculation. This
methodology may be found in sections
XQ through XVHI of appendix A to part
132. The purpose of this methodology is
to provide Great Lakes States with
guidance on evaluating pollutants from
both point and nonpoint sources when
there is insufficient data to develop a
Tier I criterion.
The Steering Committee intended that
tho outcome of a Tier II analysis would
ba a somewhat conservative value to
reflect the increased uncertainty
surrounding a more limited database.
This consideration resulted in the
development of a methodology which
produces more stringent (lower) values
where there are fewer data and higher
values as the database increases. EPA
agrees that a uniform method will
advance the goals of the Great Lakes
Critical Programs Act of 1990, and is
proposing the method that the Steering
Committee developed.
EPA, on, a long-standing basis, has
recommended that an integrated
approach to water quality-based toxics
control bo used. This integrated
approach uses both chemical specific
and wholo effluent means for
controlling discharges. Chemical
specific water quality criteria and Tier
H values reflect the concentration and
dispersal of pollutants, or their
byproducts, through biological,
physical, and chemical processes, and
the effects of pollutants on biological
community diversity, productivity, and
stability of the receiving water. A water
qualify standard defines the water
quality goals of a water body, or portion
thereof, by designating the use or uses
to be made of the water, by setting
criteria necessary to protect the uses,
and by establishing antidegradation
policies and implementation procedures
that serve to maintain and protect water
quality. On the other hand, whole
effluent toxicity (WET) is a useful
parameter for assessing and protecting
against impacts upon water quality and
designated uses caused by the aggregate
toxic effect of the discharge of
pollutants. In particular, the WET
approach is used when the toxic agent
is unknown within the effluent or
possible chemical interactions are not
understood.
One of the advantages to having
chemical specific Tier n values is that
facilities can design treatment to
address a particular contaminant. For
whole effluent toxicity, facilities have ,
less knowledge of and experience in
designing or manipulating treatment
systems to treat the general parameter of
toxicity.
Current EPA regulations at 40 CFR
122.44(d)(l) articulate when chemical-
specific and whole effluent toxicity
limits are required in a permit to meet
State water quality standards, including
both the narrative and numeric criteria.
When the permitting authority
determines that a discharge causes, has
the reasonable potential to cause, or
contributes to an excursion of the
narrative criterion within the State
water quality standards, the permit must
contain limits for whole effluent
toxicity. The only exception to this
requirement is where the permitting
authority demonstrates that chemical
specific limits are sufficient to attain
and maintain applicable narrative and
numeric State water quality standards
(40 CFR 122.44(d)(l)(v). Likewise,
where the discharge, of a particular
pollutant causes, has the reasonable
potential to cause or contributes to the
excursion of.a State's narrative criterion,
the permit must contain effluent
limitations to control the discharge of •
that pollutant (40 CFR 122.44 (d)(vi).
These regulations provide three options
((A)-(Q) for interpreting the State's
narrative criteria for purposes of
deriving permit limits to control the
pollutant(s) of concern. These three
options focus primarily on the
derivation of chemical specific limits,
however, option (C) provides the
opportunity to utilize controls on an ,
indicator parameter or pollutant. Whole
effluent toxicity can be used as an
indicator parameter under this option.
In short, EPA regulations require the •
use of WET limits and chemical specific
limits to protect the State's narrative
water quality criteria, but also prescribe
circumstances under which both types
of limits are not necessary for a
discharger that is or may be encroaching
on the State's narrative criteria.
This NPDES regulation provides
flexibility to States in deciding which
option or combination of options to use ''
in developing acceptable levels of
discharge for the pollutants of concern.
The Great Lakes States desire consistent
implementation and application of all
.criteria, including the narrative
criterion, across the basin. The approach
used in the Great Lakes Initiative
Guidance, is equivalent to requiring a
criterion be derived using both options
(A) and (C) of 40 CFR 122.44(d)(l)(vi),
where the Tier n value will act as option
(A) and WET as option (C). With this
approach, States can ensure consistent
implementation of the narrative
criterion for water quality.
EPA recognizes that Tier n
requirements for aquatic life and WET ;
testing do overlap substantially. The
Steering Committee, however,
recommended requiring both methods
to make regulation more uniform across
the Great Lake States and to increase the
level of protection for aquatic life in the
Lakes. The Committee also expected the
relatively stringent Tier n requirements
to motivate some permittees to conduct
enough testing to support development
of less restrictive and more robust Tier
I criteria.
EPA requests comment on the need
for requiring limitations based upon
Tier It values as well as using WET in
place of a Tier II value, and other
, options for harmonizing the two
requirements. ' • , -
Elements of Michigan's "Rule 57"
process were considered by the Steering
Committee in developing the proposal
for the Tier II methodology. "Rule 57"
is a two-tiered approach for calculating
regulatory values for toxic substances.
In the absence of sufficient aquatic -
toxicity data for a Tier I calculation, this
approach allows for calculation of an
acute criterion by dividing the lowest
acute value for either a Daphnid sp.,
rainbow trout, or fathead minnow by a
factor appropriate for the species
combination. These factors were derived
from a statistical analysis developed by
Michigan with the intent of producing
a criteria that is more restrictive than
one calculated with a Tier I database 80
percent of the time. A chronic value is
calculated by dividing the acute .
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Federal Register /Vol. 58, frTo.;72 / Friday,'April 16, 1993 /Proposed Rules 20855
criterion by a laboratory derived or
default acute-chronic ratio.
. While the "Rule 57" Tier H approach.
answered the need for a method .
whereby a smaller database could be
used to derive values, it usedjoxicity :
studies for only three species (rainbow
. trout, fathead minnow, and daphnids).
• Even if additional toxicity data existed
for a giveii pollutant, those data would
'not be used to derive a Tier II value. The
; Initiative Committees sought a method
that provided the option of utilizing all
available, acceptable data for-pollutants
notmeeting the Tier I-dkta requirements
(e.g., a method that utilized data on
aquatic species .from fewer than eight;
families}. '"'--.-•
Another methodology considered'was
EPA's draft "Guidelines for Deriving
Ambient Aquatic Life Advisory ' •'-
Concentrations" (Office of Water
Regulations & Standards, 1987), which
is available in the administrative record
for this rulemaking. This approach
allowed the use of more data than "Rule
57." Acutelvalues for one to twenty .
• species of aquatic animals could be used
to derive a value in place of a Tier I
criterion. The 1987 draft Guidelines also
> applied factors to calculate conservative
values and used assumed ACRs when
there were not enough experirnemtally-
derived ACRs. However, the adjustment
factors in this method were not based on
an analysis of empirical data, but
chosen by using best professional
judgment. The 1987 draft Guidelines
were never actively used by EPA due to
recommendations by the EPA's Science
Advisory Board that the factors be
statistically derived. Although the '.
Initiative Committees favored the use of
as much data as possible, the 1987 draft
Guidelines were not chosen because of
the severe drawback of not having
statistically derived factors.
-EPA considers the Tier H
methodology proposed as part of the.
Great Lakes Guidance to be an.
improvement over the basic concepts
within Michigan's:"Rule 57" and the '
1987- draft Guidelines. For the method
proposed, elements of Michigan "Rule
57" and the 1987 draft Guidelines were
expanded upon and components of
studies described by Host, et al. (199.1) •
in the draft paper, "Analysis of Acute .
and Chronic Data for Aquatic Life,"
were utilized. These documents are
available in the administrative record-
for this rulemaking.
The Tier n methodology uses factors
obtained in .the statistical analysis
described by Host, et al: (1991) to derive
Tier 31 values from data for one to seven
of the requisite eight taxonomic families
necessary for Tier I calculations.
Depending upon the number of Tier I
minimum data requirements satisfied in
the database, different adjustment
factors are .applied to the lowest Genus
Mean Acute Value to arrive at the :
Secondary Acute Value (SAV). These
adjustment factors are intended to relate
the results of one to seven toxicity tests
toaFAV. . •' '•:-•• - ,. ; . ,.
In its December 16,1992 report to :
EPA, "Evaluation of the Guidance for
the Great Lakes Water Quality
Initiative," EPA's Science Advisory
Board (SAB) stated that it agreed with
the concept of Tier I and Tier H criteria
but was concerned that the minimal
data base currently required in Tier 2
water quality criterion—a single aquatic
toxicity test—is inadequate. (See section
I.F of this preamble for further
discussion of the SAB report.) States
and Tribes sometimes need to regulate
discharges, however, when a full
complement of aquatic toxicity data (as '
specified in the Tier I method) is not
available for a particular pollutant. The
method proposed provides a consistent .
mechanism jEor the Great Lakes States to
regulate those pollutants with little data.
Although a Tier H value may be -;
developed using a single aquatic
toxicity test, EPA believes that few.'if
any, Tier H values, based on a single
data point, would be derived for use in.
control mechanisms. The methodology ,
requires States and Tribes to use. as
many acceptable.data as exist. The State
or Tribe could not arbitrarily choose a" _ = .
single aquatic toxicity test to.derive a
Tier n value if other data exist. The ,
approach proposed requires the
maximum amount of .quality
information to be utilized before any. .
Tier II value can be derived. Moreover,
EPA believes that information from one
aquatic toxicity test, if properly
conducted pursuant to the methods
described in this Guidance; is sufficient
to form the basis for a Tier n value to
prevent interference with designated
uses. EPA invites comment on whether
the minimum data base required for Tier
H aquatic life criteria is adequate.
-" The Science Advisory Board also
suggested use of short term chronic
toxicity tests to derive a Tier n valued
overcoming the cost :of completing
standard chronic toxicity tests. EPA
invites comment ori whether it is
appropriate to utilize short term chronic
tests to derive Tier n values.
In its report the SAB also stated that
there were some new fairly inexpensive
short cut methods with some plants,
invertebrates, and fishes which offer
many advantages over acute data with
extrapolations to chronic effects of other
species. The SAB report gave no
suggestions on specific methods. EPA
could not evaluate this suggestion
without further guidance on which
methods the SAB specifically ,
recommends. EPA invites comment on
whether shortcut toxicity methods
should be utilized to derive Tier H
values and specifically asks for ,
recommendations on specific methods.
The SAB did specifically recommend
that the Mayer method of the "infinite
LC Zero" should be considered as'an
alternative when there is only a single
'. acute toxicity test for a given pollutant.
This method, "Statistical Approach to-..
Predicting Chronic Toxicity of
Chemicals to Fishes from Acute
Toxicity Test Data," is an approach to
predicting chronic toxicity from acute -
toxicity data. Simultaneous
, consideration is given to concentration,
degree of response, and time course of
effect from an acute toxicity test. The .
method utilizes a consistent endpoint
(lethality).and degree of response (zero
percent) to predict chronic lethality
from acute toxicity tests. The method
• assumes that concentration-response is
a continuum in times and the mode of
action for lethality is similar under v
acute and chronic exposures. The
method can predict growth effects from
chronic lethality but is not intended to -
predict chronic reproductive effects.
The literature supporting the method is
available in the administrative record "
for.this rulemaking. The corresponding'
software (PB 92-503119) and the -
supporting literature (PB 92-169655)
may also be obtained through the ,
National Technical Information Service
(NTIS). EPA requests comment on the
use of this method to develop chronic
Tier n values and'invites comment on
alternative toxicity methods, to obtain
data, for use in the Tier n methodology.
The "Analysis of Acute and Chronic
Data for Aquatic Life," Host, et-al, 1991
leport presented several options for
statistically developing adjustment
factors using data from National criteria
documents,. In the proposed Guidance :
only one of those options is utilized.
EPA solicits comment on the option
chosen as well as the other options : .
described in Host et al. For example,.
: with the assumption of an 80th percent
probability, these adjustment-factors,
range from 242, when data from only
one taxonomic family exists, to 7.2,
' when seven of the Tier I minimum data
requirements are satisfied. These
adjustment factors may be found in
Host, et al, and its supporting . -••-•. '
documentation. "Analysis of Acute and
Chronic Data for Aquatic Life" is
available in the administrative record
for this rulemaking. If a further
restriction is made that one of the
genera represented must be either
"Ceriodaphniasp", "Daphnia sp" or
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
"Simocephalus sp" the adjustment
factors, assuming an 80 percent
probability, range from 20.5, for one
taxonomic family, to 3.6 where data for
seven taxonomic families exist. Table
in-3 lists the adjustment factors which
result when different percentiles are
assumed.
TABLE III-3.—Adjustment Factors
[With Daphnid Required]
Sample Size
50 ,„
80
85 „
Percentile
1
4.9
20.5
93.5
2
3.2
13.2
57.8
3
2.6
8.6
50.5
4
2.4
6.5
41.8
5
2.2
5.0
31.0
6
2.0
4.0
22.Q
7
1.9
3.6
13.1
For the proposed Tier n approach, the
Initiative Committees chose to use
adjustment factors which required data
for one of the three daphnid genera
named above and also chose to use the
80th perccntile. EPA is proposing to
require the use of data from daphnids
because they appear to be the most
sensitive species for many pollutants of
concern. The proposed choice of the
80th percentife by the Great Lakes Water
Quality Initiative Steering Committee
was a policy decision. It meant that 80
percent of the time, the calculated Tier
II acute values would be at least as
restrictive as a Tier IFAV if the
minimum data requirements for a Tier
I calculation were satisfied. The
Steering Committee made the judgment
that the adjustment factors associated
with the 80th percentile were
appropriate from a statistical and
technical standpoint. EPA is unaware of
information or data which would*
indicate that this judgment is
unreasonable. EPA invites comment on
the selection of an 80th percentile in
establishing adjustment factors.
Additionally, EPA invites comment on
the usa of factors "with daphnid data"
as opposed to the higher adjustment
factors that would be necessary if data
for the specified daphnids are not
required,
A separate statistical analysis, within
"Analysis of Acute and Chronic Data for
Aquatic Lifa" (Host, et al., 1991), was
used to derive a default ACR of 18.
When fewer than three experimentally-
dcrivcd ACRs exist, enough assumed
ACRs of 18 would be used so that the
total of the ACRs equals three. This
acute-chronic ratio of 18 is also based
on an 80th percentile to correspond
with the adjustment factors chosen to
derive the SAV. EPA requests comment
on the use of assumed ACRs in place of
experimentally derived ACRs, and
particularly on the use of 18 as the
default ACR.
The Tier n methodology proposed
employs all appropriate toxicity data
available for a pollutant, uses
statistically derived adjustment factors
based on existing National criteria, and
produces values which are generally
conservative relative to a comparable
Tier I criterion. Sample calculations of
Tier n values are available in the
administrative record for this
rulemaking. EPA invites comment on
acceptable alternatives to a tiered
approach. EPA also invites comments
on the approach proposed as well as
alternatives.
D. Conformance to the Clean Water Act,
Great Lakes Water Quality Agreement
and Great Lakes Critical Programs Act
0/1990
Section 118(c) of the Clean Water Act
requires EPA to develop, inter alia,
guidance on minimum water quality
limits to protect human health, aquatic
life and wildlife in the Great Lakes
System. The CPA states that the
proposed Guidance shall be no less
restrictive than the provisions of the
Clean Water Act, National water quality
criteria and National guidance, and
shall conform with the objectives and
provisions of the Great Lakes Water
Quality Agreement.
1. Tier I Aquatic Life Criteria and
Methodology
a. Comparison With the Clean Water
Act. Section 304(a)(l) of the CWA
authorizes EPA to develop and publish
criteria for water quality accurately
reflecting the latest scientific knowledge
on the kind and extent of all identifiable
effects on, among other things, health
and welfare, including plankton, fish,
and shellfish, which may be expected .
from the presence of pollutants in any
body of water, 33 U.S.C. 1314(a)(l).
Under this authority, EPA developed
provisions for deriving water quality
criteria for waterbodies nationwide.
These provisions are contained in the
1985 "Guidelines for Deriving
'Numerical National Water Quality
Criteria for the Protection of Aquatic
Organisms and Their Uses." The
proposed Guidance on Tier I aquatic life
criteria methodology, as well as the
criteria proposed thereunder, are based
. on and are consistent with the 1985
National Guidelines. EPA believes that,
although they are not identical to the
1985 Guidelines and individual
National criteria in all details, they are
generally no less restrictive.
First, as discussed above in this
section of the preamble, EPA has not
proposed Tier I aquatic life criteria for
eleven pollutants for which National
criteria exist (aldrin, chlordane, DDT,
endosulfan, heptachlor, PCBs, lead,
toxaphene, aluminum, silver and
chlorpyrifos). EPA is also proposing to
require as part of the Great Lakes
Guidance only an acute criterion for
lindane, although there are National
criteria for both acute and chronic
effects. EPA believes that these
decisions, however, will not result in
less stringent control of these pollutants.
Under the implementation scheme
proposed, Great Lakes States and Tribes
would be required to derive values for
these pollutants using the Tier II
method whenever the State or Tribe
determines that it is necessary to control
any of these pollutants. The State or .. -
Tribe would have to compare the Tier
II value to any existing State criteria for
the same pollutant. If the Tier n value
is more stringent, the Tier II value
would supersede the existing criterion
and the Tier II value would be used to •
derive permit limits and other control
" mechanisms. (If the existing criteria is
more stringent, the State or Tribe would
have the option of using either number.)
As described elsewhere in this
preamble, the Tier II method derives
conservative values to compensate for a
limited data base. Consequently, EPA ,
expects that Tier n values will be more
stringent than existing standards for .
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federal Register / Vo1-
^Friday. April 16; 1993 ^Proposed Rules ':]- 20857
these pollutants in eighty percent of all
cases. ""• ";•• ',' : -", . ; - ' "' ' . •/
Furthermore, dl but four of Tier I ,
criteria for aquatic life proposed are
equivalent to or more restrictive than
the current National criteria. EPA
believes that the proposed Tier I criteria
for cadmium, chromium IE and izinc are
not significantly less restrictive than the
existing National criteria ^because the
differences between these proposed. .
criteria and the National criteria are
minor. Furthermore, EPA believes that
the proposed criteria are more
appropriate because they are based on
': more recent data. EPA, however,
requests comment on the option of
promulgating the National criteria for
• those pollutants which have more
stringent National criteria values.
The difference between the proposed
criterion and current National criteria
for protection against the chronic effects
of mercury is considerably larger.
Nonetheless, EPA believes that, overall
protection will not be reduced. The
chronic aquatic life criterion for
mercury became less restrictive than the
current National criterion when EPA
eliminated all consideration of Final
Residue Values data from the
calculation of the criterion. As '
explained earlier, EPA is proposing to
delete Residue Values from'all aquatic
life criteria for the Great Lakes 'because
it is proposing separate; specific wildlife
criteria in the proposed Guidance. EPA
is proposing a wildlife criterion for
mercury of 180 |ig/L (or 0.00018 ng/L)
that is more restrictive than the National
chronic aquatic life criterion for
mercury (0.012 ug/L). Since both the ,
aquatic life and the wildlife criteria will
; apply in all portions of the Great Lakes
basin, EPA believes that protection will
be maintained. '-...•-
b. Conformance With the Great Lakes
Water Quality Agreement. A comparison
. of the Tier I criteria proposed herein
with the pollutants for which the ,
Agreement specifies a numeric standard
for a specified pollutant/parameter .
reveals that, in all but'a few cases, the
Agreement's standards are more .'.'•:
conservative. EPA nevertheless believes
that the numeric criteria in the proposed
Guidance", as well as the methodology
. upon which they were derived, conform
with the provisions "and objectives of the
Agreement This position is based on
the fact that the current Agreement, hi
EPA's opinion, needs revision. The
current criteria in the Agreement,
created in 1978 as "interim" numbers,
were for the most part a result of
negotiation. EPA has not been able to
find any record revealing then: technical
or policy bases. Further, EPA believes
that the standards on the Agreement
, were not developed in consultation with
the States or Tribes. The numeric
criteria in the proposed Guidance are
based on sound scientific criteria
development methodology and are :
proposed after consultation with the
States, as required by the Supplement to
Annex I to the Agreement's Specific
Objectives, v '
EPA also believes that Congress did
not intend to compel EPA to replicate
the pollutant concentrations for the
protection of aquatic life set out in
Annex 1 to the Agreement, Section
li8(c)(2)(A> of the CWA directs EPA to
develop numeric limits on pollutants in
the Great Lakes-waters, but leaves the
selection of the limits to EPA's
discretion. EPA believes that Congress
would have been very explicit if it had
intended to deprive EPA of the
authority to exercise its own judgment
on the technical and scientific issues
involved. Moreover, the legislative
history shows that Congress knew and
approved of the ongoing work of the
Great Lakes Initiative Committees. S.
Rep. 101-339,101st Cong., 2dSess. at,
18 Gune 27,1990); 136 Cong. Rec.
S15616 (Oct. 17,1990) (remarks
prominently on the committees' work, it
is reasonable to assume that Congress
expected EPA to develop its own
criteria). Consequently, EPA does not
believe that "conformance" with the -.-''
Agreement requires the numeric criteria
proposed to be identical to or no less
restrictive than individual Annex 1
values. Rather, EPA.'s guidance must
conform with the more general
objectives of the Agreement regarding,
the elimination or reduction to the
maximum extent practicable discharges
into the Great Lakes System. The criteria
and methodologies proposed in the
proposed Guidance conform with this ,
objective. Further, as explained above,
EPACannot evaluate the technical basis
for the Agreement's standards. EPA
reasonably prefers to propose standards
which are supported by extensive *
record. ~ •";-"-.
EPA believes that the position taken
by the Initiative Committees to the
Guidance criteria and methodologies
proposed herein could serve as a basis
to amend and supplement the Great
Lakes Water Quality Agreement is
reasonable. Besides being consistent
with the terms of the Agreement, which
require the United States to, after
consultation with the States, revise and
supplement the Specific Objectives
included therein, it is also consistent
with the intent of the CPA.
2. Tier H Criteria Methodology ;
a. Comparison With the Clean Water
Act. EPA's current guidance arid
regulations for water quality standards
contain nothing directly analogous to "
the Tier U methodology and values
proposed for aquatic life. Rather, under
the existing program many States and
-tribes interpret narrative criteria on a
case-by-case basis to ensure that
discharges of pollutants that lack ';
, numeric criteria will not adversely
affect human health or, the environment.
Other States and Tribes develop their
own numeric criteria based on methods
requiring less data than the existing
National criteria guidance requires. The
Tier n methodology and values •-:•;--•'
proposed would not be-less restrictive'
than this existing approach. In the first
place, EPA expects that eighty percent
of the Tier fl values that the States and
. Tribes derive will be more restrictive
than the State and Tribal standards that
EPA could approve for the sarnie
pollutants under the current CWA
.program because the adjustment factor
'incorporated into the Tier n approach,
as proposed, imposes more structure on
the process of translating narrative . v •• ..
criteria into numeric values. States and
Tribes currently have very broacL ,
discretion when regulating pollutants '
that are subject only to narrative criteria
The proposed Guidance is more
rigorous than the current National
: requirements in this area. Finally, the
. proposed approach' will result in more.'.
uniform control of pollutants lacking
NatipnaFcriteria in the Great Lakes
States and Tribes. .
b. Conformance With the Great Lakes
Water Quality Agreement. Tierllisa
conservative methodology designed to.
^establish-environmentally protective
limits on the discharge of pollutants
into the Great Lakes System. The
methodology will result in the •
regulation of the discharge of .certain
pollutants which heretofore in certain
Great Lakes States may have gone
unregulated by a specific numeric
criteria, instead being regulated by
narrative criteria or by indicator
pollutants such as biological oxygen
demand (BOD). The Tier H methodology
is-consisterit with the .purpose of the
Agreement, "to eliminate or reduce to
the maximum extent practicable the
discharge of toxic substance in toxic -
-amounts" and serves as a translator
mechanism of the Agreement's narrative
standards found in the General ,
Objectives, Section D, Article HI. The
Tier n methodology will enhance
regulatory efforts in the Great Lakes
basin, will serve its purpose of
promoting consistency in the-regulation "
of toxics in the Great Lakes basin, and
is .therefore also in conformance with, - .
the Agreement. •' : ' ,.. " •- •'•'•,
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20858
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
IV. Bioaccumulation Factors
A. Introduction
Aquatic organisms, exposed to certain
typos of chemicals, will accumulate
those chemicals in their bodies.
Chemical uptake is due to exposure
from tho water the organisms live in, the
food they eat, and other sources of the
chemical. This process is called
bioaccumulation. For certain chemicals,
uptake through the food chain is the
most important route of exposure. As
lower trophic level organisms are
consumed by higher trophic level
organisms, the tissue concentrations of
those chemicals may increase with each
trophic level so that residues in top
carnivores may be many orders of
magnitude greater than the
concentration of the chemical in the
environment While the exposure
concentration In the environment may
be too low to affect the lowest level
organisms, this biomagnification
process can result in severe health
effects for the consumers of top trophic
level aquatic organisms.
For the purpose of the Great Lakes
Guidance, bioaccumulation factors have
bean developed to reflect the propensity
of an organism to accumulate a
chemical in its tissues, when exposure
to the chemical is from all sources
including food and water.
Bioaccumulation factors serve several
purposes in the Guidance.
First, in order to properly account for
potential exposure to a chemical, both
the wildlife criteria and the human
health criteria have been developed to '
be a function of the bioaccumulation
factor. That is, for example, all else
being equal, if two chemicals have
different bioaccumulation factors, the
chemical with the higher
bioaccumulation factor will have the
lower criterion. Thus, prior to deriving
a human health or a wildlife criterion,
a bioaccumulation factor for the
chemical must be established.
Secondly, within the Great Lakes
System both wildlife and humans may
bo susceptible to adverse health effects
from chemicals which are highly
bloaccumulative. While not the only
indicator of a chemical's potential harm,
the bioaccumulation factors are believed
to be an indication of which chemicals
may be of greatest concern within the
Great Lakes System. Thus, the human
health bioaccumulation factors have
been used to identify a list of chemicals
which warrant increased attention, and
more stringent controls, within the
basin. In this Great Lakes Water Quality
Initiative (GLWQI), these chemicals are
called the Bioaccumulative Chemicals
of Concern (BCCs). See Discussion of
BCCs in section H.G above.
B'. Bioaccumulation Factors
The proposed Great Lakes Guidance
methodology for developing
bioaccumulation factors (BAFs) is
discussed below. The proposed
Guidance on bioaccumulation is
compared to existing National guidance
and practices, and differences are
discussed. Throughout the discussion,
issues for which EPA specifically
invites comment are highlighted.
The procedure for developing the
bioaccumulation factors is included in
appendix B of part 132 of the proposed
Guidance. Great Lakes Water Quality
Initiative Technical Support
Documents, which further discuss the
basis for the proposed Guidance and
which provide the data and
considerations upon.which the BAFs
are based, are identified below and are
available in the administrative record
for this rulemaking. Copies are also
available upon written request to the
person listed in section XHI of this
preamble. ,
Finally, EPA's expectations for
determining whether a State's water
quality standards are consistent with the
Guidance are set forth in § 132.6 of the
proposed Guidance and discussed in
section E.I of this preamble.
1. Bioaccumulation and
Bioconcentration Concepts
Bioaccumulation refers to the uptake
and retention of a substance by an
aquatic organism from its surrounding
medium and food. A bioaccumulation
factor (BAF) represents the ratio (in L/
kg) of a substance's concentration in
tissue to its concentration in the
surrounding water in situations where
both the organism and its food are
exposed and the ratio does not change
substantially over time. Field measured
BAFs are based on field data.
A steady-state bioconcentration factor
(BCF) is the uptake and retention of a
substance by an aquatic organism from
the surrounding water only, through gill
membranes or other external body
surfaces. Laboratory measured BCFs are
the result of laboratory experiments
using aquatic organisms. In this
preamble, methodology, and Technical
Support Document, wherever the term
BCF is used, steady state is implied.
2. Existing EPA Guidance
EPA, in developing criteria to .protect
humans and wildlife from the
consumption of contaminated aquatic ,
organisms, has relied upon the BCF and
occasionally BAF to relate water, ;
concentrations to the amount of a
contaminant that is ingested. The BAF
is ideally the best factor to use because
it accounts for the uptake by aquatic
organisms of a chemical from all sources
including diet, sediments, and the water
itself. However, EPA has also
recognized the difficulties in deriving
scientifically valid BAFs. BAFs are a
scientific area which is still evolving.
This is exemplified by EPA's past and
current guidance. For example, EPA's
1985 "Guidelines for Deriving
Numerical National Water Quality
Criteria for the Protection of Aquatic
Organisms and Their Uses" (1985
National Guidelines), states:
* * * although BCFs are not too difficult to
determine, very few BAFs have been
measured acceptably, because it is necessary
to make enough measurements of the
concentration of the material in the water to
show that it was reasonably constant over a
long period of time, over the range of
territory inhabited by the organisms.
This document is available in the
administrative record for this
rulemaking. Copies are also available
upon written request to the person
listed in section XIII of this.preamble.
Because of the difficulty in deriving
BAFs, most of the existing human
health and aquatic life National criteria
are based upon BCFs. BAFs reported in
the scientific literature need to be
carefully evaluated to ensure that they
adhere to the criteria of acceptability
outlined in EPA's 1985 National
Guidelines methodology.
Bioconcentration factors are
determined either by measuring
bioconcentration in laboratory tests
(comparing fish tissue residues to
chemical considerations in test waters),
or by predicting the BCF from a
chemical's octanol-water partition
coefficient (Kow or P). The log of the
octanol-water partition coefficient (log
Kow or log P) has been shown in the
scientific literature to be empirically '
related to the bioconcentration factors
(e.g. Mackay, 1982; Connell, 1988; Veith
et al., 1979).
In 1980, EPA issued its "Guidelines
and Methodology Used in the
Preparation of Health Effects ,
Assessment Chapters of the Consent
Decree Water Criteria Documents" (45
FR 79341, November 28,1980). These
guidelines serve as the basis for nearly
all of the current National human health
criteria. In these guidelines, the
following equation (Equation 1) is,used
to predict BCFs for organic chemicals in
the absence of laboratory measured
BCFs (Veith et al, 1979).
Equation 1:
log BCF = 0.85 log Kow ^-0.70
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Federal
/ Vol. 58, No. 72 I Friday, April 16, 1993- /Proposed Rules
20859
More recently, in 1991, EPA issued
the final "Technical Support Document,
for Water Quality-based Toxics Control"
(EPA 505/2-90-001) and a. draft
document entitled "Assessment and
Control of Bioconcehtratable ,;,',:
Contaminants in Surface Waters" for, ,
notice and comment (56 FR13150),
which are available in the ,
administrative record for this ;• • .-•
. rulemaking. These documents, relying
on additional research into this
relationship between BCF and log Kow,
recommend that a slightly different
equation (Equation 2) be used to derive
BCFs hi the absence of laboratory
measured BCFs^Veith and Kosian,
1983). ,
• Equation 2: ' ,
log BCF = 0.79 log Kovv-0.40
This equation is used to estimate' •. "
BCFs in EPA's computerized
Quantitative Structure Activity
Relationships (QSAR) database, and is
also the equation proposed for use in
- the proposed Guidance. • •> .
EPA's 1991 National guidance
documents, the Technical Support
Document for Water Quality-based
Toxics Control" and draft "Assessment
and Control of Bioconcentratable •
Contaminants in Surface Waters",
recommend a methodology for
estimating the BAF where there is an
absence of a field-measured BAF. This
methodology multiplies the BCF by a
factor which accounts for the
biomagnification of a pollutant through
trophic levels in a food chain. As larger
predatery aquatic organisms, such as
pike, consume other fish and aquatic
organisms, the amount of Ibiaa ,
contaminants in the. consumed fish is
concentratedin the predator. The factor .
which accounts for this
biomagnification through the food chain
is called the food chain multiplier
(FCM) in these 1991 National guidance
documents. EPA calculated the FCMs
using a model of the step-w&j"increase
in the concentration of an organic
chemical from phytoplankton (trophic
. level 1) through the top predatory fish *
level of a food chain (Thoinana, 1989).
The FCMs were determjned by first
running Thomann's modsy to generate
BCFs and BAFs for trophic level 2, and
BAFs for trophic levels 3 aud 4. This
was done for a range of logKow values'
from 3.5 to 6.5, at interval|pf a tenth of
log KOW value. Second, thejCMs for
each log Kow value in this rauga Were
calculated using the following ,,
equations: J *. ;
For trophic level 2
, . BCF2 -
For trophic level 3 (small fish):
BCF2
For trophic level 4 (top predator fish):
FCM =
BAF4
BCF2
Where: ••--•-.•• :
BCF2 is the BCF for trophic level 2
organisms, and BAF2, BAF3 and BAF4
are the BAFs for trophic levels 2,3, and
4, respectively,.
The resulting FCMs for trophic levels
2,3, and 4 are shown in Table B-l of
. appendix.B of part 132 for log KOW
values ranging from four to 6.5. '
Thomann (1989) compared predicted
BAFs for trophic level 4 with measured
BAFs from the Great .Lakes and ;.
concluded that, within an order of
magnitude, the model-predicted BAFs
were a reasonable representation of the
observed data for chemicals with log
Kow values in the range of 3.5 to 6.5.
At log KOW values of 6.5 arid greater,
the relationship between log KQW and
the FCM is less certain, for reasons
described hi section IV.B.3.c'of the ....'-.
preamble. Existing EPA guidance
recognizes that FCMs may range from
0.1 to 100 for such chemicals, and
provides that a FCM of iOO could be '.'.-
used as a conservative standard value in
the absence of chemical-specific BAF
, information.
EPA evaluated its own BAF
prediction procedure using field .
studies, as reported in appendix I of the
draft "Assessment and Control of
Bioconcentratable Contaminants in •
Surface Waters"'guidance document. In
these field studies, residues in receiving
water organisms were predicted using
:EPA's BAF prediction procedure and
Were then compared to the measured
tissue residues. These studies
demonstrated acceptable agreement
between measured and predicted tissue
residues which, therefore, demonstrated
that EPA's BAF prediction procedure
provides acceptable BAF values. The
results.of this EPA evaluation are '
presented in detail in two EPA field
studies (Burkhard et. al. 1991,1992),
which are available in the/
administrative record for this >
rulemaking. -
3,The Great Lakes Guidance for BAFs
The bioaccumulation concepts
contained in the proposed Guidance,
data supporting these concepts, and
additional details are also discussed in
the GLWQI Bioaccumulation Factors
Technical Support Document, which is
available in the administrative record
for this rulemaking. Proposed
•-..§ 132.4(a)(3) requires the use. of the BAF
methodology in appendix B of part 132
in the derivation of criteria for
protecting humans and wildlife; EPA
believes that the BAF is the best
. predictor of the concentration of a
chemicd within fish tissue m the Great
Lakes because it hicludes conisideration
of the uptake of contaminants from
food, sediments, and the water itself; •
and is, therefore, the most appropriate
factor for the developing criteria. In the
past, EPA has rarely used the BAF to
develop criteria due to the lack of
reliable field data. However, EPA now
believes thatthe BAF can be
approximated from BCF data and
information concerning .
. biomagnification through the food
chain; ' - ; : ' ;.'
- a. Measured and Predicted BAFs. The
proposed Guidance lists three methods:,
to derive BAFs for non-polar organics, '•'
. listed belowin order of preference: A
BAF measured hi the field, preferably in
fish collected from the Great Lakes
which are at the top of ttie food chain;
a BAF predicted by-multiplying a'BCF
measured hi the laboratory, preferably
(but not required) on a fish species
indigenous to the Great Lakes, by the-,
food chain multiplier; and a BAF
predicted by multiplying a BCEr
calculated from the log KOW (using
Equation 2) by the food chain
multiplier. - "'-
,'••• Measured BCFs for organics can be
determined in several ways. These '
include analytical measurements 6f
tissuelad"water using gas " .-•'•
chromatography (GC) or high pressure
liquid chromatography (HPLC). Another '
method for determining a laboratory-
measured BCF is to use radio labeled
organic chemicals. However, the radio •-
labeled compound leaves open a
possibility of error in several areas. In
radio labeliag, the organism may
metabohzft a.metabohte of the parent
compound thereby inflating the
measuredBCF. There is also a
possibility of contammation of the
labeled compoimd. ' , '
For inorganic chemicals, either a
measured BAF or BCF must be used.
This is because no method is available
for reliably predicting BCFs or BAFs for
inorganic chemicals; BCFs and BAFs
vary from one invertebrate.tp another, ;
from one fish to another, and from one
tissue to'another within a species. As •
.reported in the "GLWQI , xT
Bioaccumulation Factors Technical
Support Document", which is available
hi the administrative record for this
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20860 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
rulemaking, accumulation of inorganics
varies significantly between species and
types of tissues.
EPA Invites comment on: How to
predict a BCF from log P; the acceptable
methods for measuring BCFs with radio
labeled organic compounds which
could inflate the measured BCF, as
opposed to BCFs more conventionally
measured using gas chromatography or
HPLC; whether a BCF is preferable to
measured or predicted BAFs as
proposed; the derivation of BAFs for
inorganic chemicals such as mercury
and selenium; and the GLWQI methods
for developing a value for a BAF and the
preferred order. In addition, in its
December 16,1992 report, "Evaluation
of the Guidance for the Great Lakes
Water Quality Initiative," EPA's Science
Advisory Board (SAB) stated that:
Field BAFS must be interpreted very
carefully, end it should be recognized that
(hey may contain substantial errors and
variability dua to the following reasons: (1)
Analytical methodologies generally
dolerrnino total concentrations all of which
may not bo biologically available; (2) There
may bo a loss of analyte by sorption or
evaporation during sampling; (3) Incomplete
extractions may occur, especially if there is
• high organic carbon content in the water,
(4) Temporal and spatial variability in water
concentrations; (5) Variability in fish
concentrations duo to size, age, sex, etc.
EPA agrees that these are valid
considerations for selection of field-
measured BAFs and invites comment on
whether appendix B of part 132 should
provide more guidance on the quality of
acceptable data, and what additional
factors should be reviewed for
acceptability of data.
b. Standard Lipid Values. Consistent
with the existing National guidance, the
proposed Guidance relies on the
fundamental assumption that an
organism's ability to bioaccumulate
organic chemicals is proportional to its
lipld content. For example, an organism
with a two percent lipid content would
accumulate twice the amount of a
chemical as an organism with a one
percent lipid content, all else being
equal.
In order to determine a BAF for
organic chemicals, for use in deriving
wildlife and human health criteria, it is
necessary to know the percent lipid
content of the organisms being
consumed. The proposed Guidance
proposes that standard lipid values
higher than the three percent
recommended for human health in
EPA's 1991 "Technical Support
Document for Water Quality-based
Toxics Control" be used to represent the
percent lipid content of the fish and
other aquatic organisms consumed by
humans and wildlife in the Great Lakes
basin. Fish consumption patterns differ
widely around the United States, and
this is especially true in the Great Lakes
basin. Humans also typically eat fish
fillets which generally have lower lipid
content than the whole fish generally
consumed by wildlife. Therefore,
standard lipid values have been
developed separately for humans (5.0
percent) and for wildlife (7.9 percent).
The rationale behind the selection of
these standard lipid values for humans
and wildlife is discussed below.
i. Standard Lipid Value for Human
Health BAFs. The proposed Guidance
proposes a standard lipid value of 5.0
percent in edible tissue fof use in
determining human health BAFs for
organic chemicals. Percent lipid data for
edible tissue (mostly skin-on fillets) *
were gathered from the fish contaminant
monitoring programs in Michigan,
Wisconsin, phio, Indiana, New York ,
and Minnesota. These data are
summarized in the BAF Technical
Support Document. Lipid values for
skin-on fillets are likely to be higher
than lipid values for skinless fillets.
Skin-on fillets typically include a layer
of fatty tissue between the skin and
muscle. The skin-on fillet is the tissue
sample used by most of the Great Lake
States' fish consumption advisory
programs, and, therefore, the bulk of
available data are for skin-on fillets.
However, many anglers remove the skin
and other fatty tissue when they prepare
their fish for cooking. Consumption
advisories recommend this practice.
Therefore, use of skin-on data to
determine the standard lipid values will
provide an extra margin of safety to the
many anglers who remove the skin from
the fillet.
In selecting the standard lipid value
for human health BAFs, the Technical
Work Group considered lipid data for
the following fish groups: Lipid data for
salmonids (trout and salmon) only; lipid
data for salmonids and non-salmonid
game fish (perch, walleye, bass, etc.);
and lipid data for all fish (game and
nongame species).
Mean lipid values and standard
deviations for each of the options are:
6.73±3.27 for salmonids; 5.02±3.55 for
all game fish; and 5.25±3.68 for all fish.
The Technical Work Group proposed to
use the value for all game fish of 5.02
because this option best represented the
range of species typically consumed by
people in the Great Lakes basin.
The Technical Work Group also
considered mean lipid values weighted
by human consumption patterns, and
the typical weight of sport-caught game
fish by species. Consumption was
addressed through creel survey data
from the Great Lakes, and typical
species weights from the State
contaminant programs. The resulting
overall consumption weighted mean for
all game fish was 4.72 ± 2.42 percent
lipid. Because these results were not
different statistically from the means of
the unweighted data, the Initiative Work
Group proposed to use the unweighted
mean value of 5.02 percent for the
human health BAFs.
ii. Standard Lipid Value for Wildlife
BAFs. The proposed Guidance proposes
a standard lipid value of 7,9 percent for
wildlife BAFs, based on consumption of
whole fish. The standard lipid value for
the wildlife BAFs was dgte.rmined using
whole fish lipid data from the U.S. Fish
and Wildlife Service National
Contaminant Biomonitoring Program
and the Canadian Department of
Fisheries and Oceans. These data are
summarized in appendix B of the BAF
Technical Support Document.The 7.9
percent lipid value is the mean of lipid
.values for all fish, game and nongame,
in all of the Great Lakes. Data for all fish
were used because wildlife typically are
nondiscriminatory consumers of fish.
iii. Comments requested. EPA. invites
comments on the standard percent lipid
values proposed in the proposed
Guidance. Specifically, comments
should address whether the trophic '
levels chosen to derive the human
health and wildlife standard percent '
lipid values are appropriate, or the
consumption-weighted human health
value of 4.7, should be used in lieu of
the 5.0 percent lipid value currently
proposed. In addition, to the extent that
the currently proposed values of 5.0 and
7.9 percent lipid overestimate mean
- lipid values of fish consumed by Great
Lakes humans and wildlife, use of the
values will provide a margin of safety.
EPA specifically solicits comment on
whether such a margin of safety is
necessary. The data on which die mean
percent Upid values are based were
obtained by measuring percent lipids
using a variety of solvents. The value of
percent lipid obtained will depend to
some extent on the solvent used. It has,
been shown that the analytical method
used to determine percent lipid can
affect lipid values because different
solvent systems extract different
fractions of total lipids (Randall et al.,
1991). EPA invites comment on what
solvent should be used hi the
measurement of percent lipids.
c. Food Chain Multipliers. As
discussed above, EPA proposes to use
food chain multipliers (FCM), based on
a biomagnification model, to derive
BAFs for organic chemicals when field
studies do not exist. Food chain
multipliers derived from the model
-------
Federal Register /.. Vof. 58, NQ. 72 /Friday, April 16, 1993 /' Proposed Rules
20861
range from less than one to 100, Under
the proposed Guidance, FCMs greater-
than one would usually apply to organic
chemicals with log IQ,W values in the
range of 4.0 to 6.5. The ECMs which
result from the Guidance proposed are
listed in Table B-l of appendix B of part
' 132. , - - , • / : , •'"..' , -
In the proposed Guidance, when
BAFs for human health are derived from
BCFs through the application of a FCM/
,_ the appropriate FCM based on the
chemical's log KOW is selected from the
trophic level 4_eolumn in Table B-l of
appendix B of part 132. This assumes
. that humans typically eat trophic level
4 (top, carnivore) fish species. For
wildlife BAFs, FCMs from trophic levels
3 and 4 are used, and BAFs for
invertebrates or aquatic plants may be
used on a case-by-case basiftCseis
Methodologies for the Development of
Wildlife Criteria and Values in
, appendix D to part 132). "
- For chemicals with log KOW values
.t greater than 6.5 (superlipopbilic
chemicals), existing EPA guidance
recommends FCMs in the range of 0.1
to 100 due to the uncertainty of
predicting bioaccumulation for this
group of chemicals (U.S. EPA; 1991). For
example, at the low end of this range,
FCMs of 0.1 may be appropriate for
some chemicals such as superlipophilic
polycyclic aromatic hydrocarbons,
These chemicals are metabolized
rapidly by many fish, and not only is
uptake through the food chain negated
as a result, but rapid metaboltsni can
result in bioaccumulation less tEan
predicted using bioconcentration
models such as Equation 2 (Mimi and
Dookran, 1989). -
In contrast, at the high end of the -
range, use of a FCM (at 5.0 percent
lipid) of 100 provides a reasonable
• estimate ofa measured BAF for ,
octachlprostyrene (log K<>w=7.94). The
mean of two measured BAFs (0.9 and,
4.3 million) for this chemical is 1.9
million (Oliver and Niimi, 1985; Oliver
and Niimi, 1988). The predicted BAF
based on measured BCF.S times a FCM
of 100 is 6.6 million. The factor of 3,5
difference between measured and
predicted BAFs indicates a FCM of 100
for this chemical is reasonable. The BAF
for 2,3,7,8-TCDD of 50,000 (5.0 percent
lipid) is an example 6f a superlipophilic
chemical (log Kow=7.36) with a FCM of
about one. . : "
From the above examples,^ is clear
that predicting the food chain
biomagnificatipn of superlipophilic -
chemicals is" difficult. For this reason,
the proposed Guidance recommends
that chemical-specific data be used to
determine the ECM for this group of
chemicals. However, if no chemical-
specific data are available, the Steering
Committee proposed a FCM of one for
superlipophilic chemicals as a standard
value. ' •-"-•-" •;- :
EPA invites comment on: the basic
premise that a BCF may, overestimate or
underestimate a BAF; the
appropriateness of FCMs based on the
Thomann model; the appropriateness of
using a FCM of one when chemical-
specific values for superlipophilic
chemicals are not available; and
possible alternatives to the Thomann.
model for predicting BAFs from BCFs.
d. Effect of Metabolism on BAFs.
Many organic chemicals that are taken
up by aquatic organisms are transformed
to some extent by the organism's
metabolic processes, but the rate of '•"
metabolism varies widely from one
chemical to another! For most organic
chemicals, metabolism increases the '
depuration rate and reduces the BAF.
However, metabolism does not always
- result in a lower BAF. Because they are
based on field measurements, measured
BAFs automatically take into account
any metabolism that occurs. Predicted
BAFs that are obtained by multiplying
a measured BCF by a FCM automatically
take into account the'effect of
metabolism on the BCF, but do not take
into account the effect of metabolism on
the FCM. Predicted BAFs that are
obtained by multiplying a predicted'
BCF by a FCM make no allowance for
metabolism* -
• Available information indicates that.
some organic chemicals, such as
polynuclear aromatic hydrocarbons
(PAHs), are metabolized by aquatic
organisms, but that the extent of that
metabolism varies substantially from
one PAH to another and from one
species to another. The available
information, accordingly, is not .
amenable to a general prediction of the
effect of metabolism on the magnitude
of the BCF, FCM, or BAF.'
!F6r these reasons, the BAF
methodology being proposed for organic
chemicals includes a provision that
Both human health and wildlife BAFs
should be reviewed for consistency with all
available data concerning the
bioaccumulation of the chemical. In
particular, information on metabolism,
molecular size, or other physicochemical
properties which might enhance or inhibit
bioaccumulation should be considered. The
BAFs may be modified if changes can be
justified by the data, (section VI.D.5 of
appendix B of part 132)
EPA expects States and Tribes to follow
this guidance on a site specific basis if
necessary in developing the BAFs used
for developing human health and
wildlife criteria and values. ,
One approach that might be usefully "
.applied to individual organic chemicals
for which a, measured BAF is not : "
available but for,which a measured BCF
is available is as follows. If metabolism
affects the BCF, the measured BCF will
usually be lower than would be
, predicted on the basis of log KOW. The
relationship.between log KOW and BCF
for non-metabolized chemicals can be
used to back calculate an "effective log
KOW" from the measured BCF. An
"effective FCM" can then be based on
the "effective log KoW." A predicted BAF
that takes into account metabolism can
then be obtained by multiplying the
measured BCF by the "effective FCM."
This approach would provide an
allowance for metabolism for organic
chemicals for which a measured BCF is
available but for which .a measured BAF'
is not available.
•" EPA solicits comment on: Suggested
methods to adjust predicted BAFs for
chemicals that are metabolized; the
types of chemicals or chemical groups •
for which the BAF might be affected by \
metabolism, and the possible use of an
"effective FCM", as described above, to~
account for metabolism when measured
BAFs are not available, but measured
BCFs are available; and any other
alternative methods hot explicitly
described above. •
• e. Bioavailability. The predicted .
human health and wildlife BAFs for
organic chemicals are based on the total
concentration of the chemical in water.
For highly lipophilic chemicals,
however, a substantial percentage of the.
total concentration can be associated
with particulate and dissolved organic
matter in water and be unavailable for
accumulation. Thus, the bioavailability
.• of the chemical in water might vary
with the organic carbon contentof the -.:
water. Even in "clean" laboratory water,
a substantial percentage of a chemical'
with a:Log P of seven can be associated
with organic matter in the water.
Application of BAFs to a site might,
therefore, be improved by adjusting for
the difference in bioavailability between
the-site water and the water on which
the predicted BAFs were based. This
might best be done by deriving BAFs in
terms of "freely dissolved" chemical,
i.e., that which is dissolved and not -.'-•-
associated with other organic matter. "
The concentration of freely dissolved
chemicals will usually have to be
, predicted, but it might be measurable in
.some cases.
- EPA invites comment on: The merit of
the above approaches for refining the
.predicted BAFs, in light of the fact that
standard lipid values, FCMs and , "-./; '
measured and predicted BAFs do not
take into account bioavailability and
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
partitioning; and any additional
recommendations for dealing with
bioavailability and partitioning of
chemicals of concern.
f. Other Uses ofBAFs. In the proposed
Guidance, BAFs are used to identify
chemicals of greatest concern within the
Great Lakes basin. Chemicals identified
as Bioaccumulative Chemicals of
Concern (BCCs) are those for which
extra controls are necessary as specified
in the proposed implementation.
procedures and under the
antidegradation procedures in the
proposed Guidance. See discussion of
BCCs in section n.G, above.
EPA invites comment on: Other
approaches which might he used to
identify pollutants of greatest concern to
the Great Lakes (e.g., chemical release
and production data plus chemical
tojddly and persistence); and the use of
BAFs to identify these pollutants of
greatest concern.
4, SAB Comments
In Us December 16,1992 report,
"Evaluation of the Guidance for the
Great Lakes Water Quality Initiative,"
EPA's Science Advisory Board (SAB)
reviewed the Initiative's draft BAF
methodology prepared in December
1991. The SAB found that the BAF
procedure is more advanced and
scientifically credible than existing BCF
procedures, and that the use of the BCF,
FCM, and BAF approach appear to be
fundamentally sound. The SAB made a
number of comments, suggestions, and
recommendations, however, concerning
elements of the draft BAF methodology.
Ono of the specific recommendations is
discussed above (section IV.B.3.a of this
preamble). Other SAB comments
concerned the following areas: use of
the Thomann model or suggested
alternatives, metabolism,
supcrlipophilie chemicals, the
bioavailable form of a metal (mercury
and selenium), and additional equations
relating BCF to log P.
In preparing the BAF methodology
and mis section of the preamble for the
publication of the proposed Guidance,
EPA hts revised the methodology and
clarified the discussion of issues since
the time of the SAB's review to address
many issues including those raised in
the SAB's final report. In those
revisions, EPA added additional
information and discussion of several
issues. Many of the revisions were in
response to informal comments from the
SAB, tha draft SAB report, and the final
SAB report. Nevertheless, EPA invites
comment on all of the issues raised by
the SAB concerning the BAF
methodology, including comment on
specific suggestions for improving the
methodology. •
5. Relationship of the Guidance to
Current EPA Guidance
Section 118(c)(2)(A) of the Clean
Water Act requires that the Great Lakes
Water Quality Initiative (GLWQI)
Guidance be no less restrictive than the
• Clean Water Act and National water
quality criteria and guidance, and
conform with the objectives and
provisions of the Great Lakes Water
Quality Agreement (the "Agreement").
The GLWQI Guidance proposes four
essential differences from existing EPA
guidance in the bioaccumulation area.
First, criteria are derived using field-
measured or predicted BAFs rather than
BCFs, as in existing section 304(a)
criteria guidance. This change will
result in more stringent criteria for most,
if not all, chemicals in the Great Lakes,
and is consistent with EPA's existing
guidance ("Technical Support
Document for Water Quality-based
Toxics Control" (EPA 505/2-90-001)
•and draft "Assessment and Control of
Bioconcentratable Contaminants in
Surface Waters" (56 FR13150)). Second,
the hierarchy of preferred methods to
obtain a BAF reverses the recommended
order in the 1991 draft "Assessment and
Control of Bioconcentratable
Contaminants in Surface Waters". EPA
anticipates making a similar change to
its final "Assessment and Control of-
Bioconcentratable Contaminants in
Surface Waters."
Third, the "Guidelines and ,
Methodology Used in the Preparation of
Health Effects Assessment Chapters of ,
the Consent Decree Water Criteria
Documents" (45 FR 79341, November
28,1980), the 1991 "Technical Support
Document for Water Quality-based
Toxics Control", and the draft
"Assessment and Control of
Bioconcentratable Contaminants in
Surface Waters" used three percent
lipid for human health BAFs versus the
5.0 and 7.9 percent used for human
health and wildlife BAFs in the GLWQI
Guidance, respectively. This change
will result in more stringent criteria for
organic chemicals in the Great Lakes,
and is justified .in light of Great Lakes- .
specific data on fish lipid values.
The fourth issue relates to the lipid/
BAF relationship for superlipophilic
chemicals. The ability to predict
bioaccumulation is poor for organic
chemicals whose log Kow is greater than
6.5. Such chemicals are called
superlipophilic because of their very
strong affinity for lipids. Certain factors,
however, have been shown to inhibit
the bioaccumulation'of superlipophilic
chemicals. These include the chemicals'
very low .solubility in water and the
inhibition of molecular transport due to
the large size of the molecules. Because
of this, use of a FCM to derive a BAF
may result in an overestimation of the
bioaccumulation of these
superlipophilic chemicals.
Current EPA guidance ("Technical
Support Document for Water Quality-
based Toxics Control") states that the
FCM for superlipophilic chemicals can
vary between 0.1 and 100, and provides
that a FCM of 100 may be used for the
top predator trophic level in the absence
of chemical-specific information. The
proposed Guidance recommends a FCM
of 1 in the absence of chemical specific
data. (In other' words, the BAF equals
the BCF unless chemical specific data
are available.) Current EPA guidance
("Technical Support Document for
Water Quality-based Toxics Control")
recommends a range of values, and the
proposed Guidance, with additional
data, recommends a specific default
value of 1. ,
EPA is soliciting: bioaccumulation
data on any superlipophilic chemical
listed in appendix A of part 132 of the
GLWQI Technical Support Document;
suggested techniques for deriving a BAF
for superlipophilic chemicals, in the
absence of chemical-specific data; and a
recommended alternative FCM value (in
lieu of the proposed value of one) for
superlipophilic chemicals to be used in
the absence of chemical-specific data.
6. Adoption of Water Quality Standards
Consistent With the Proposed Guidance
The Great Lakes Guidance for .
deriving BAFs is included in appendix
B of part 132. Examples ofBAFs derived,
using this methodology are also set forth
in appendix B of part 132 of the
proposed Guidance. The Great Lakes
, Water Quality Initiative
Bioaccumulation Factor Technical
Support Document, which discusses the •
basis for the proposed methodology and
which sets forth the data and
considerations upon which the
individual BAFs are based, is available
in the administrative record for this.
rulemaking. Copies are also available
upon written request to'the person
listed in section Xm of this preamble.
Section 132.4 of the proposed
Guidance requires that States and Tribes
adopt requirements into their water
quality standards that are consistent
\vith the BAF methodology in appendix
B of part 132. The State or Tribal
regulations need not duplicate the
methodology in the proposed Guidance
verbatim, but, when presented with a
given data base, the methodology
• adopted by the State or Tribe will be ,
expected to demonstrate to EPA's
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satisfaction that the same BAF will be
produced as would be produced using
the final methodology in the Great Lakes
Guidance. To the extent that current
. State or Tribal regulations or statutes --
already contain a BAF methodology .
which is at least as stringent as the final
Guidance, the State or Tribe nsed no.t
•reproduce that guidance separately for
the Great Lakes basin.
' The States and Tribes may adopt a
methodology which results in more
Astringent (higher) BAFs than those .
"which result from the final Great Lakes
Guidance; however, this more stringent
methodology shall not be offset by less
stringent, ofcompensating, adjustments
in the derivation of.the wildlife or
human health, criteria, or in the
implementation procedures for those -
criteria. • -
:'\7. Literature Gited . -' .
Burkhard, L.P.,B.R. Sheedy, N.A. Thomas.
1991. Field Evaluation of Residue ,
Prediction Procedures Used in. EPA's
Guidance: " Assessment and Gontrol of
Biocpncentratable Contaminants in -
' Surface Waters."JJ.S. EPA National
Effluent Toxicity Evaluation Center, Rpt. -
'#10-91. ' '..'.- ,
Burkhard, L.P., B.A. Sheedy.N.A. Thomas.
" 1992, Field Evaluation of Residue
Prediction Procedures Used in.EPA's
Guidance: "Assessment and Gontrol of
Bioconcentratable Contaminants in
Surface Waters." Louisiana Study, U.S.
EPA National Effluent Toxicity
Assessment Center, Rpt. #1-92.
.Conneil, D.-W. 1988. Bioaccumulatipn
behavior of persistent organic chemicals
: with aquatic organisms. Pages 117-159
In: Review of Environmental • f
Contamination and Toxicology, Volume
101.
Mackay, D. 1982. Correlation of
bioconcentration factors. Environ. Sci.
Technol. 16: 274-278.
Niimi, A.J. and G.F. Dookhran. 1989. Dietary
absorption efficiencies and elimination
rates of polycyclic aromatic
hydrocarbons (PAHs) by rainbow trout
(Salmo Gairdneri). Environ. Tpxicol.
Chem. 8: 719-722.
Oliver, B.C. and A.J. Niimi. 1985. .
Biocpncentration factors of some
halogenated organics for rainbow trout:
" limitations in their use for prediction of
environmental residues. Environ. Sci. ,
- Technol; 19: 842-849."
Oliver, B.C. and A.J. Niimi. 1J988.
, Trophodynamic analysis of
polychlorinated biphenyl congeners and
other chlorinated hydrocarbons in the
Lake Ontario ecosystem. Environ. Sci. ••
Technol. 22: 388-397.
Randall, R.C., H. Lee IL R.J. Ozretich, J.L. -
Lake and RJ. Pruell. 1991- Evaluation of
selected lipid methods for normalizing
pollutant bioaccumulation. Environ.
Toxicol. Chem. 10:1431-1436.
Thomann, R.V. 1989. Bioaccumulation
Model of Organic Chemical Distribution
in Aquatic Food Chains. Environ. Sci.
Technol. 23: 699-707.
U.S. EPA, 1991. Technical Support , :
Document for Water Quality-based toxics
control. EPA/505/2-90-001 U.S. EPA,
Office of Water, Washington, D.C,
Veith, G.D., D.L. DeFoe and B.V. Bergstedt.
1979. Measuring and estimating the
. bioconcentration factor of chemicals in
fish. J. Fish. Res. Bd. Canada 38:1040-
••-1048. - '• . - ; : ,-
Veith, G.D. and P. Kosiaff. 1983. Estimating
Bioconcentratibn Potential from Octanol/
, Water Partition Coefficients. Chapter 15 .
in PCBs in the Great Lakes. Mackay, D.,
,R. Patterson,'S. Eisenreich, and M. . -.'•
.Simmons (eds.) Ann Arbor Science'. •
V. Human Health
A. Introduction . • •
• The proposed Great Lakes Water
Quality Guidance for human health is
described below. As with the Guidance
for aquatic life discussed earlier, EPA is
proposing a two-tier approach for
human health. Minimum data
requirements for Tier I. criteria and Tier
II values are discussed later in this
section. The proposed Great Lakes
Water Quality Guidance is compared
below with existing National Guidance
for developing human health criteria,
and the differences are discussed.
Sample human health criteria have
been calculated using the proposed
methodology for 20 chemicals. The 20
chemicals chosen for criteria
development were selected from the
Great Lakes Water Quality Initiative
(GLWQI) group of chemicals of concern
listed in proposed 40 CFR part 132, .-••.•
Table 6, to represent a broad cross
section of the types of chemicals found
in the Great Lakes basin. They include:
Halogenated and non-halogenated
chemicals; bioaccumulative and
nonbioacoimulative chemicals; and
organic and inorganic compounds. The
intent of the chemical selection was to
test the proposed methodology against a
broad range of chemicals and to '
demonstrate how the criteria
development process will be carried
out. Chemical selection- from among the
chemicals of concern was not made oh -'
the basis of health risk priorities, .but
more from the perspective of ,
demonstrating the proposed
methodologies' applicability to all types
of chemicals.
Once the proposed methodologies
haveheen.finalized, EPA may in the
future propose additional Tier I criteria
and Tier H values for the GLWQI
chemicals of concern or for other
pollutants of concern on a health
priority basis (see section II.D.2 of this
.preamble). In addition, microbial agents
which are of concern in the Great Lakes
may be the focus of future criteria
development as well. Developing" r
criteria for microbial agents will require.
the development of a new methodology
to assess microbial risks. (The
methodologies presented in today's
proposal are designed to assess risks
from chemical contaminants; _
adjustments in methodology will be
required to assess the risks from
micfobial pathogens.) Pending such.
future EPA action, the Great Lakes
States and'Trihes will be expected to
use the final human health methodology
to derive Tier I criteria and.Tier II .
values as described in section n.D.2 of
the preamble. ' ":
, Although EPA requests public '
comment on all aspects of the proposal,
issues are raised throughout the
following discussion for which EPA • :
:specifically mvites comments. The
proposed human health methodologies
for calculation of cancer and noncancer
Tier I criteria and Tier H values are
included hi appendix C to part 132. A
Technical Support Documents for
Human Health rHuman Health TSD")
which further discusses the basis for
today's proposal, and Human Health
Criteria Documents which provide the
data arid considerations upon which the
20 proposed sample human health
criteria calculations are based, are
available in the administrative record
for this rulemaking; Copies of these
documents are also available upon :
written request to the addresses listed in
section XIII of this preamble. The,
•Human Health TSD contains
'discussions and rationales for the
selection of different exposure •
assumptions and risk assessment
approaches incorporated'in the
proposed human health methodologies.
• Finally, EPA's expectations" for
determining whether.a State's water
quality standards are consistent with the
Guidance are set forth in section 132.4
and corresponding preamble
discussions. .' " ; ' . ' '
B. Criteria Methodologies .
Existing EPA guidelines for .the
development of human health criteria
were established in 1980. These
guidelines can be found at 45 FR 79347,
dated November 28,1980 ("1980
National Guidelines"). The objective of
the 1980 National Guidelines is;
* *'* to estunate ambient water
concentrations which do not represent a
significant risk to the public. 45 FR 79347.
This objective is retained in today's
proposed Guidance. The Guidance sets
forth criteria and methodologies to
derive human health criteria which will'
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Federal Register / Vol. 58, No.. 72 / Friday, AprillS, 1993 / Proposed Rules
not result in zero risk, but will provide
a level of protection likely to be without
appreciable risk. At some level of upper
bound incremental risk, generally
between one in ten thousand (10 ~4) and
one in ona million (10-
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20865
non-carcinogenic effects, no identifiable
threshold has been demonstrated. '•'_••
. Chemicals which may exert non-
threshold non-cancer effects include
genotoxic teratogens and germline
mutagens. EPA has recognized this;
potentiaiinits "Proposed Amendments,
to Agency Guidelines for Health
Assessment of Suspect Developmental
Toxicants" (Proposed Amendments to
Agency Guidelines for Health
Assessments of Suspect Developmental
Toxicants, 56 FR 63798, (December 5,
1991)) and in the Guidelines for
Mutagenicity Risk Assessment ,
(Guidelines for Mutagenicity .-,. '
Assessments, 51 FR 34007, (September
24,1986)). Today's.proposed Guidance
would require that a threshold
mechanism of action be assumed in ;
deriving criteria for protection against
noncancef effects, unless it is
demonstrated on a case-by-case basis
-that there is no threshold with respect
to a given chemical's toxicity efi:ect(s).
Therefore, while today's proposed
Guidance goes beyond the 1980
National Guidelines by acknowledging
that noncancer effects may not
demonstrate a threshold, it is consistent
with the .latest revision of the guidelines
for developmental and mutagenic risk
assessments.
In the rare instance that this type of
/chemical is encountered, it is v
recommended that States and Tribes
confer closely with EPA prior to
establishing a noncancer criterion on
the basis of a non-threshold effect.
3. Choice of Risk Level
Human health water quality criteria
for cancer-causing substances are
„ typically expressed in concentrations'
associated with a plausible upper bound
level of increased risk of developing
cancer. EPA derives criteria using a :
cancer potency factor which is an upper
95th perceritile confidence limit of the
probability of response based on human
or experimental animal data. This ,
plausible upper bound estimate means
EPA,is reasonably confident that the
"true risk" will not exceed the risk
estimate derived by this model, may be,
less than predicted, and could be as low
as zero. ,
In practice, the plausible upper bound
i cancer risk generally accepted by States,
Tribes and EPA for exposure to
individual chemicals present hi surface
waters typically ranges between one in
ten thousand (I'D ~4) and one in a
million (10 ~6). Under the Guidance
proposed today, the criteria derived '
correspond; to a plausible upper bound
increased risk of developing cancer of i
in 100,000 (10 ~ 5) over a lifetime of
exposure. The choice of risk level was
based on the best professional judgment
of the Technical Work Group and is
within a range that EPA has historically
used in EPA actions, and approved for
State and Tribal actions. The majority of
the Great Lakes States traditionally have
used a 10 ~5 risk level in setting their
water quality criteria. ,.
EPA invites comment on this choice
of risk level, and on alternate risk levels,
such as 10~6 and 10~4 which could be .
adopted in the. final Great Lakes human :
health criteria methodology. Decreasing
the risk level by a factor of 10 (i.e., from
10~3 to 10~6) results hi a corresponding
10-fold decrease in numeric criteria and
values (e.g., from 10 ug/L to 1 Hg/L),
while increasing the risk level by a
factor of 10 (i.e., from 10~5 to 10~4)
results in a corresponding 10-fold . ,
increase in criteria and values. -f
Consistent with the 1980 National
Guidelin.es, under today's proposal,
criteria for protection against non-
cancer effects are derived so as to
prevent hypdthetically exposed
individuals (i.e;, thoseconsuming
pollutant-bearing fish and drinking
water at .the rate assumed in the criteria-
derivation formulas explained below) ;
from receiving a dose of the chemical
above that which is calculated to.
correspond to no appreciable risk of
adverse effect, based on a threshold
model of chemical activity.
4. Acceptable Dose
Today's proposal and the 1980
National Guideliriesrare based on the
; principle that the potential for a
chemical to cause an adverse effect (e.g.,
carcinogenicity, toxicity) depends on:
Dose; the amount of the chemical
needed to induce the adverse effect; and
duration of exposure. Under today's
proposed Guidance, the dose associated
with a one in one hundred thousand
plausible upper bound risk of -.-•.".-
developing cancer from lifetime
exposure to a carcinogen is called the
Risk Associated Dose. (RAD). The dose
of a noncarcinogen expected to result in
no appreciable risk of adverse health
effects upon lifetime exposure is
referred to as the Acceptable Daily
Exposure (ADE),
a. RAD. Determining a Risk
Associated Dose (RAD) under today's
proposed Guidance will typically
involve the following steps: Establishing
through review of scientific studies on
humans and/or animals that enough
evidence exists regarding the potential
'of the chemical to cause cancer to
warrant treating it as a known, probable
or possible human carcinogen for
purposes of criteria derivation; using
available data (typically from animal
studies) to establish a relationship
between the dose of the chemical
administered and carcinogenic
response; translating a dose/response
relationship based on animal data into
an assessment of risk to humans; and
calculating the specific dose to humans
that will correspond to the particular
risk level of interest (in this case, the
10~5 risk level). It is important to note
that many of these steps may have
already been Conducted by EPA for a
particular chemical and the results
made available to the public through
EPA's Integrated Risk Information -
System (IRIS). It is recommended that
•IRIS be consulted when developing a
RAD. , ; ,•;.. ..- •
The first step in developing a RAD
involves determining whether scientific
evidence supports treating the chemical
as a human carcinogen for purposes of '
criteria derivation. The considerations
to weigh in making this determination K
are described in section n. A. of the
proposed methodology and the Human
Health TSD and can also:be found in the
1986 EPA Guidelines for Carcinogen
Risk Assessment (51 FR 33992).
; The second step hi deriving a RAD
involves using scientific studies that
correlate varying doses of a chemical
with carcinogenic response (-'.dose
response studies") to establish a dose
response relationship for the organism
exposed hi the study that will allow
estimation .of carcinogeniaresponse at •-..
doses other than those/actually
administered hi the study. Typically,
insufficient data are available from V •
epidemiological studies to form the
basis for derivation of a dose response
relationship suitable for criteria
development.'Where such • :
epidemiologic. data are available,
however, today's proposed Guidance
specify that they should he used to
calculate a criterion. In the usual
situation where epidemiological studies
are insufficient for this purpose, the
Guidance provides for the use of animal.
data.. When animal studies are used to
estimate effects on humans, data from
species most biologically relevant to
humans are generally preferred (i.e., a
species in which pharmacpkinetics and/
. or toxic mechanisms of action appear
closely related to humans. For example,
it is generally accepted that results from -
rodents are more likely to be relevant
than results from birds). In the absence,
.of data to distinguish the most relevant
species, data fronrthe most sensitive
animal species tested, i.e., the species
"exhibiting a carcinogenic response at
the lowest administered Gose (given a
relevant route of exposure), should be
used. -.'•"• ;
Typically, dose response tests are
conducted at relatively high dqses of the
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
chemical of concern. The purpose of
such an assay design is to ensure that an
effect will be seen, if one is to occur,
during the timeframe of the study. As a
practical matter, it is generally not
feasible to conduct a valid laboratory
test to measure the dose that will
actually yield only one cancer among a
hundred thousand test organisms, even
though it is that level of response that
would ba most relevant for purposes of
deriving criteria pursuant to today's
proposed Guidance. Accordingly, the
information available on cancer
response in test organisms exposed to
high doses of a chemical is used to
estimate the level of cancer response
that would likely occur if doses were
substantially reduced. Various models
have been developed to perform this
extrapolation, based in part on various
theories of how chemicals operate to
produce cancer. Consistent with EPA's
general assumption, discussed above,
that carcinogens act in a non-threshold
manner, EPA is proposing that a
ynearized Multistage Model ("LMS")
bo used to extrapolate from actual
animal bioassay data to the dose/
response relationship expected at low
doses, unless it can be established on a
caso-by-casa basis that another model is
moro appropriate. EPA uses Global '86
to determine cancer potencies. Global
'88 is a revised LMS derived by Howe,
Crump, and Van Landingham (1986).
(Howo, R., K. Crump, and C. Van
Landingham, Computer Program to
Extrapolate Quantitative Animal
Toxicity Data to Low Doses. Prepared
for EPA under subcontract S2-251U-
2745 to Research Triangle Institute.) Use
of the LMS for this purpose is consistent
with the 1980 National Guidelines. A
LMS yields a very protective estimate of
potential cancer response at low doses
because it is based on a non-threshold
assumption of carcinogenidty. EPA
estimates risks using the 95 percent
upper confidence limit on the risk
associated with the low extrapolated
dosos, thereby deriving a "plausible
upper-bound" estimate of risk
associated with any dose. The model
assumes a linear relationship between
dose and effect, allowing derivation of
a "slope factor" or "potency factor"
representing the incremental risk
associated with every additional unit of
doso expressed in milligrams of the
chemical per kilogram of body weight
per day.
EPA believes the scientific basis
supporting the LMS is better than for
other current mathematical
extrapolation models, and for this
reason it has been adopted as the
primary basis for risk extrapolation to
low levels of the dose response
relationship. As the 1986 EPA
Guidelines for Carcinogenic Risk
Assessment state:
When data and information are limited,
and when much uncertainty exists regarding
the mechanism of carcinogenic action,
models or procedures which incorporate low
dose linearity are preferred when compatible
with the limited information. At present,
mechanisms of the carcinogenesis process are
largely unknown and data are generally
limited. If a carcinogenic agent acts by
accelerating the same carcinogenic process
that leads to the background occurrence of
cancer, the added effect of the carcinogen at
low doses is expected to be virtually linear
(Crump et al., 1976). In the absence of
adequate information to the contrary, the
1986 Guidelines for Carcinogenic Risk.
provide that linearized multistage procedure
will be employed.
Under today's proposed Guidance,
other models, such as the "time-to-
tumor" model or ones based on
modifications of the LMS model, may be
used on a case-by-case basis if the data
are more appropriately considered by
that model. For example, in some
studies there are low survival rates of
tested animals due to disease or
laboratory-related stress. Modifications
to the LMS model can account for poor
survivability and still allow for a
calculation of cancer potency factor
based on tumor occurrence in the
surviving test animals and the predicted
cancer fate of the population that did
not survive.
One of the difficulties sometimes
encountered in this aspect of criteria
development is that the animal study
being used to derive a dose/response
relationship was not of sufficient
duration (due to premature death of test
organisms) to measure cancer
development over the natural lifespan of
the species. In this circumstance, the
proposed Guidance requires that the
potency factor be adjusted to account for
potentially unobserved tumors due to
the short study duration. As explained '
more fully in the 1980 National
Guidelines (45 FR 79352) and the
Human Health TSD (section Ili-B), the
rationale for this requirement is that the
rate of the tumor incidence increases
with age, given constant exposure. A
short-term study is thus likely to
underestimate carcinogenic potential. •
EPA has developed a factor (L/Le)3,
xvhere L is the natural lifespan. of the
test species and Le is the duration of the
study, which will adjust for less than
lifetime duration studies. Use of this
specific factor is required for use with
today's proposed methodology. The
slope factor adjustment will be
conducted for mice and rat data if the
study duration (Le) is less than 78
weeks for mice or 90 weeks for rats, by
multiplying the slope factor by the
factor (L/Le)3. EPA requests comment
oh whether the use of this adjustment
factor for studies with less than lifetime
duration is appropriate. , .
The third step in deriving a RAD is to
translate the dose/response relationship
derived for a test organism into an
estimated dose response relationship for
humans. In today's proposed Guidance,
as in the 1980 National Guidelines, it is
assumed that a dose expressed as
milligrams per unit of body .surface area
per day will yield equivalent cancer
responses in test animals and humans.
Thus a "surface area species scaling
factor" is proposed for use in deriving
a dose response relationship for humans
that is based on animal data. EPA uses
the surface area scaling factor based on
evidence that among different
mammalian species many physiological
rates, especially ventilation, basal
metabolic, and clearance rates tend to
scale in proportion to surface area. It has
also been found to hold for the acute
therapeutic effects of anticancer agents.
Where experimental doses are
described in terms of dose per surface
area, the surface area scaling factor is
easily determined by comparing the
surface area of the test organisms with
that of the average human. However,
scientists typically express doses
applied in laboratory tests in terms of •
milligrams of chemical per unit of body
weight of the test organism per day.
Since, to a close apprpximation, the
surface area is proportional to the two-
thirds power of the body weight (as
would be the case for a perfect sphere),
exposures in milligrams per kilogram of
body weight per day raised to the %
power would also be considered as"
yielding equivalent cancer responses in
test animals and humans under today's
proposal. This approach is consistent
with the 1980 National Guidelines.
Certain researchers, including Travis
and White (1988) (see the Human
Health TSD), have determined that a
three-fourths exponent may be more
appropriate, based on a reassessment of
historical data on anticancer drugs. EPA
' specifically requests comment .on the
proposed use of a two-thirds exponent,
and the possible use of a three-fourths
exponent, for performing the above-
described calculations.
Not all Federal agencies use a surface
area species scaling factor to translate a
dose/response estimate for test
organisms into an assessment of risk to
humans. The U.S. Food and Drug
Administration (FDA), for example, has
traditionally assumed that equivalent
doses expressed as milligrams per unit
of body weight will yield equivalent
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Federal Register / Vol. 58, No. 72 I Friday, April 16,. 1993 7 Proposed Rules 20867
cancer responses (a "body weight
species scaling factor"). Scientists differ
on whether a body weight or surface
area species scaling factor is>most
appropriate. Some scientists believe a
surface area scaling factor fits the data
best for drugs and chemicals in which
• metabolic effects are key to the _ ;•
mechanism of action, such as anticancer
drugs. Other studies support views that
body weight scaling may be moire
appropriate tot other types of chemicals.
As a practical matter, the surface area
scaling factor will generally result in a
more stringent potency factor than the
body weight scaling factor.
An inter-agency work group (Iriter-
. Agency Pharmacokinetics Group)
comprised of EPA, FDA, and the
Consumer Product Safety Commission
(CPSC) has been working on tha issue of
appropriate, consistent scaling factors
for use by all of the agencies in
developing risk assessments [57 FR
24152 (June 5,1992)). If the woirk group
completes its work prior to publication
of the final Great Lakes Guidance, and
if it determines that a species scaling
factor other than the surface area or
body weight scaling factors discussed
above should be used, EPA will reopen
the public comment period to allow
comment on possible use of the work
group's proposal in the final Great Lakes
Guidance. In any event, however, EPA
seeks comment on whether use of a
body weight, surface area, or some other
scaling factor should be used in the final
, -Great Lakes Guidance. .
After the above steps have been used
to calculate a cancer potency factor for
humans, the final step in calculating a
RAD is to use the cancer potency factor
to calculate a dose in milligrams per
kilograms per day that corresponds to a
plausible upper-bound incremental
cancer risk of one in one hundred --.. •
thousand. This is the risk associated
dose or RAD.
b. ADE. For non-carcinogens, today's
proposed Guidance establishes a data
hierarchy for calculating the Acceptable
Daily Exposure (ADE). This process is
the same one used by EPA's reference
dose (RfD) development process but
differs in the amount of data required to
develop a number. In some cases, an
ADE may be identical to an EPA RfD if
the same data and judgments are used.
However, these values may differ for
reasons explained later in this section,
' and so to distinguish the two terms from
each other, a different term (ADE),.
defined slightly differently, is being
used in the proposed Great Lakes
Guidance. EPA defines an RfD as "an
estimate (with uncertainty spanning
perhaps an order of magnitude) of a
daily exposure to the human population
(including sensitive subgroups) that is
likely to-be without appreciable risk of
deleterious effects during a lifetime."
U.S. EPA 1992, "Reference Dose:
Description and Use in Health Risk ".1..
Assessments." IRIS. Online: Intra- _•
Agency Reference Dose Work Group,
Office of Health and Environmental
Assessment, ECAO, Cincinnati, Ohio,
This definition was used as the basis for
defining an ADE. In today's propdsal,
ADE has similarly been defined as an
estimate of the maximum daily dose of
a substance which is not expected to •
result in adverse effects to the general
human population, including sensitive
subgroups.
Calculating an ADE for a chemical'
involves the following steps:
Determining whether there is evidence .
from epidemiologic or animal studies
that exposure to a chemical may result
in adverse noncancer health effects;
using available data to determine a
threshold dose value that is likely to he
without appreciable risk of adverse
effect; and reducing this threshold dose
value to account for uncertainties
inherent in the risk, assessment to yield
an acceptable daily exposure for '. .
humans. Many noncancer effects are ,
clearly deleterious to human health, and
therefore clearly warrant derivation'of
water quality criteria to protect exposed
populations from them. Such effects "•
include reproductive impairment, -
developmental tqxicity, impaired organ
function, reduced body and organ
weights, immunotoxicity, etc. For a
detailed discussion of what constitutes
an adverse effect, refer to U. S. EPA
1992, "Reference Dose: Description and
Use in Health Risk Assessments." IRIS.
Online: Intra Agency Reference Dose
Work Group, Office of Health and '
Environmental Assessment, ECAO, V
Cincinnati, Ohio. There are some ,,
instances, however, where changes at
the cellular or subcellular level may be;
observed in test organisms, but it is :
unclear whether these changes are
harmful. (For example, minor increases
in enzyme activity, may or may not be
precursors to or indicators of actual
organ damage. These types of'effects
need to be further validated by
histopathological analysis to determine
if actual organ damage has occurred.)
Today's proposal provides for
noncancer criteria that are protective'..
from adverse acute, subchronic and
chronic effects including reproductive
and developmental effects (see .
appendix C to part 132, section I.B).
EPA believes that the proposed text will
allow States and Tribes to consider on
a case-by-case basis whether effects
• other than those cited in the appendix
G to part 132, section I.B, i.e.,
reproductive and developmental .
toxicity, including observed biological
changes not demohstrably linked to
adverse effects, should be considered
"adverse" for purposes of criteria
development. EPA solicits comment on
whether it should specify in the
methodology a longer list of deleterious
effects that noncancer criteria should
protect against, and whether the : ,
methodology should specifically ;
address criteria development based on
observed biological changes not
demonstrable linked to;an adverse-,
: effect. • , ''
Once it is determined that exposure to
a chemical may result in an adverse
effect in humans, available data are used
to establish a dose/response
relationship. Use of well-conducted
human studies (studies which are well
designed, peer-reviewed and which.
provide a basis for causal inference) are
favored over use of animal studies for
.this purpose. When animal studies are
used to estimate effects on humans, data
from species most biologically relevant
to humans are generally preferred (i.e.,
a species in which pharmacokinetics
and/or toxic mechanisms of action
appear closely related to humans), if it
is not possible to distinguish the animal
species that is most biologically relevant
to humans, then data from the most
sensitive animal species are generally to
be used. (The Human Health TSD,
section n, provides recommendations
on relevant test species for different test •
endpoints such as cancer, noncancer
effects, reproductive effects, etc.) EPA ,
requests comments on the described
approach and, particularly, on whether
the most sensitive animal species
" should be used as a default when the
most biologically relevant species is not
identified or whether another approach
should be used. •
From these animal data, the
experimental exposure level
representing the highest dose at which
there were no observed adverse effects
(the NOAEL) is used for calculating the
ADE. If a NOAEL has not been
: experimentally determined, the dose
associated with a lowest observed
adverse effect (LOAEL) involving
relatively mild and reversible effects (as
compared to effects at higher doses) may
be used in the case of chronic studies
(one year or longer in rodents, and 50
percent or more of the lifespan in other
appropriate test species) for ADE •
derivation. This does not preclude the
use of a LOAEL from a study with only
-.; one or two doses if the effects appear
minimal when compared to effect levels
observed at higher doses in other ,
studies. For example, there are many
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20868 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules.
studios for which only one dose has
bten tested with resulting minimal,
ravefsibla effects such as minimal
enzyme changes or body weight
decreases. These minimal changes or
effects, on their own, may not be
thought of as adverse but may be
Indicators or precursors to more severe
effects which result from extended
exposure and/or higher doses. In those
cases, while it can be argued that such
an effect may be a LOAEL, it may also
bo very close to the NOAEL.
Having established a NOAEL or
LOAEL in either an animal or
opldemiologic study, the final step in
deriving the ADE is to reduce the
NOAEL or LOAEL to account for
uncertainties in predicting acceptable
exposure levels for the general human
population. The use of "uncertainty
factors" for this purpose is common
practice by EPA in deriving noncancer
criteria. The size of the uncertainty
factor varies depending on the data
available for ADE calculation, including
whether the data are from a study on
humans or test animals, and on whether
tha study demonstrates a NOAEL or a
LOAEL. Tha 1980 National Guidelines
establish three general provisions for
deriving uncertainty factors:
* i. Valid experimental results from
studies on prolonged ingestion by
humans, \vith no indication of
cardnogenidty. Uncertainty factor=10.
ii. Valid results of experimental
studies of human ingestion are not
available. Valid experimental results of
long-term feeding studies on animals, or
valid animal studies on one or more
species, No indication of
cardnogenidty. Uncertainty factor=100.
iii. No long-term or acute human data.
Scanty results on experimental animals
with no indication of carcinogenicity.
Uncertainty factor=1000.
Since the 1980 National Guidelines
were published, additional research and
continuing EPA deliberations have
occurred regarding use of uncertainty
factors (see, e.g., U.S. EPA, 1992, IRIS;
Dourson and Stara, 1983; Regulatory
History and Experiment Support of
Uncertainty (Safety) Factors, Regulatory
Toxicology and Pharmacology. 3:224-
238). The three provisions taken from
the 1980 National Guidelines apply to
just three situations. In developing RfDs,
two additional uncertainty factors are
now applied to account for conditions
such as severity of effect when a LOAEL
is used instead of a NOAEL and
incompleteness of data set. All
uncertainty factors are judged oil a case-
by-caso basis depending on the overall
database. The default value of these
factors is 10, but other values have been
used (generally 3) and multiple factors
are often combined when 4 or 5 are used
together.
The most up-to-date EPA guidance on
the application of uncertainty factors
has been used as the basis of today's
proposal (U.S. EPA, 1992, IRIS). For a
more complete discussion of the
uncertainty factors chosen under
various data schemes, refer to appendix
A of the Human Health TSD.
Under today's proposal a composite
uncertainty factor of 30,000 is the
maximum uncertainty allowed when
deriving a Tier I criterion or Tier II
value. When deriving a Tier I criterion
the likely maximum composite
uncertainty factor applied to a 90 day
NOAEL may be 3000. The total 3000 is
based on four separate uncertainty
factors: A factor of generally 10 to
account for intraspecies variability (the
sensitivity within the human ,
population); a factor of generally 10 to
account for interspecies variability
(intended to account for the uncertainty
in extrapolating animal data to the case
of humans); a factor combined of
generally 30 to account for both
subchronic to chronic variability; and to
account for an incomplete database (i.e.,
lack of a reproductive, bioassay,
developmental toxicity studies data in
two species and a second species
general toxicity bioassay). Note here that
in. the use of these latter two factors; two
areas of uncertainty which generally
warrant a default value of 10 each have
been combined to yield a 30-fold factor.
Under Tier II, the likely maximum
composite uncertainty factor may be
30,000 which would be applied to a
greater than 28 days minimal LOAEL
(e.g., 30 day). The total of 30,000 is .
based on EPA's standard uncertainty
factors (four factors of generally 10 each
are used to account for intraspecies
variability^interspecies variability,
subchronic to chronic variability, and
incompleteness of data set) which
together warrant the use of a 10,000-fold
factor, and an additional factor of 3 to
account for the uncertainty in
extrapolating from a study greater than.
28 days but sufficiently less than 90
days to warrant a factor of 3.
The choice of appropriate uncertainty
and modifying factors reflects a case-by-
case judgment by experts and should.
account for each of the applicable areas
of uncertainty (described above) and .
any nuances hi the available data that
might change the magnitude of any
factor. Several reports describe the
underlying basis of uncertainty factors "
(Zielhuis et al., 1979; Dourson and
Stara, 1983) and research into this area
(Galabrese. 1985; Hattis et al., 1987;
Hattis and Lewis, 1992; Hartley and
Ohanian, 1988; Lewis et al., 1990;
Dourson et al., 1992; Dourson, 1993;
Renwick, 1991; 1993).
The use of such uncertainty factors
and their application has not been
without controversy in the literature.
For example, Lewis, S.C., J.R. Lynch and
I. Nikiferov, (Regulatory Toxicology and
Pharmacology, 11, pp. 314-330, (1990),
note that it seems excessive to require •
a 10-fold uncertainty factor to correct for
intraspecies variability, whereas a .. t
reading of Calabrese (1985) would
suggest that perhaps more than a 10-fold
factor is needed, Building on earlier
work of Weil (1972) and Dourson-and
Stara (1983), Lewis et al (1990) suggest
that based on 450 studies of lethal
doses, for 85 percent of the studied
chemicals a factor of 6 was adequate to
protect 99.9 percent of the individuals.
Lewis et al. (1990) state that lower
values for intraspecies adjustments are
surely adequate for this 85 percent of
chemicals; for another 15 percent,
however, a factor larger than 6 is
needed. • • •
Lewis et al. (1990) also.note that
according to some data, a factor of 10 to,
extrapolate from subchronic effects to
chronic effects is excessive. In
particular, they write that studies of 41
different chemical agents indicate that a
ratio of 3 would be adequate to
extrapolate subchronic statistics to
estimate corresponding values for
chronic exposures in all instances. This
point is similar with a careful reading of
Dourson and Stara (1983). Citing an
earlier series of toxicity experiments,
Dourson and Stara state that the ratio of
the subchronic to chronic NOAEL or
LOAEL "for more than half of the
observed chemicals are 2.0 or less".
This result indicates that the chronic .
NOAEL or LOAEL was'2-fold less than
the corresponding NOAEL or LOAEL for
more than half of the given chemicals
after subchronic exposure. Further,
Dourson and Stara write "approximately
96 percent of these ratios are below a
value of 10." Thus the empirical .
evidence on differences between
chronic and subchronic exposure effects
on laboratory animals would suggest
that use of a default uncertainty factor
of 10 in the absence of chemicakspecific
data should be regarded as a loose upper -
bound to the range of values associated
with these ratios. These factors of 10 are
not average values.
EPA defines the RfD as "an estimate -
(with uncertainty spanning perhaps an
order of magnitude) of a daily exposure
to the human population (including
sensitive subgroups) that is likely to be
without an appreciable risk of
deleterious effects during a lifetime."
U.S. EPA 1992, Reference Dose:
Description and Use in Health Risk
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Federal Register / VoL 58, No. 72 /Friday, April 16, 1993 /Proposed Rules
20869
Assessments. IRIS. Online: Intra Agency
Reference Dose Work Group. Office of ;
Health and Environmental Assessment,
ECAO, Cincinnati, Ohio. Given this
definition, it has been EPA's practice to
use default uncertainty factors of 10 that
are loose upper bounds to the potential
range of values. Nevertheless, EPA
solicits comments on the uncertainty
factors included in this proposal, and
particularly on whether other
uncertainty factors might offer hotter
assessment of risk, and he more
appropriate in deriving water quality
values and criteria.
c. IRIS. EPA currently has a process
to develop consensus on cancer slope
factors and RfDs (referred to as ADEs for
the Great Lakes). These values .are
derived by two. EPA work groups, called
the RfD/RfC and GRAVE work groups,
and made available as guidance to EPA.
program offices and to the public via a
database called the Integrated Risk .
Information System (IRIS)'. The IRIS
values (RfDs and cancer slope factors)
are recommended for use as a starting
: point by various EPA programs for the.
development of regulations and
guidance.
Today's proposed Guidance •
recommends that the IRIS cancer slope
factors and RfDs (ADEs) be considered
as a first step in deriving the Great Lakes
Human Health criteria. In certain _.
circumstances, however, deviation from
these values can be expected; First, the
Great Lakes cancer slope factors and
ADEs may differ where they are based
on new data that were not available at
the time EPA work groups derived the
IRIS values. This will ensure that the
criteria are derived based on the best
available information.
For example, the mercury value
presented in today's proposal is based,
in part, upon data that was hot
considered by EPA's RED work group.
The ADE for mercury used to calculate
today's proposed Tier IHNV is,
• therefore, different from the RfD which
currently appears in IRIS. Although this.
type of discrepancy could likely be
remedied by updating IRIS values at the
same time that Great Lakes criteria'and
values are derived, this will not always
be possible given the heavy workload of
the IRIS work groups. V
Second, EPA work groups may;not
have followed .the procedures specified'
in today's Guidance in deriving their
values, or they may have interpreted the
data differently. Where detailed risk
assessment methodology guidance is
. lacking, case-by-case decisions based on
professional judgement may differ. In r
today's proposal, when an ADE or RAD
differs from the values in IRIS, the Great
Lakes Technical Work Group may have
interpreted the science slightly'
differently, than the RfD or CRAVE work
group for a particular chemical. '
Scientific justification supporting such
deviations from IRIS guidance is
provided in the!individual Tier I criteria
technical support documents included
in the administrative record to today's :
proposal. For example, today's RAD for
dioxin is based on a cancer slope factor
which differs from the IRIS cancer slope
factor for dioxin. While both cancer
slope factors are derived using data from
the same rat feeding study, different
pathologists reviewing the slides from
that study have counted the tumors
differently, and therefore have come to
somewhat different conclusions ;'
regarding the potential of the chemical
to cause cancer. The IRIS slope factor is
based on a tumor Count conducted in
1978, while the slope factor used to
derive today's proposed criteria is based
on a tumor count of the same slides that
was conducted in 1990, using a
somewhat different protocol for
counting tumors/This issue is described
more fully in the human health criteria
document for dioxin which is available
in the administrative record for today's
rulemaking. EPA's CRAVE work group
has not yet considered whether to
change the IRIS dioxin cancer slope
factor based on this new information.
This and other new scientific
information is currently undergoing
extensive review by EPA's Office of
Research and Development as part of a
comprehensive reassessment of dioxin
toxicity, discussed in more detail below
Third, in some cases, EPA work
.groups may not have developed RfDs or
cancer slope factors for some chemicals,
or'previously calculated values have
been withdrawn from IRIS. The '/
methodology proposed today may be
used to develop cancer slope factors and
.ADEs for the purpose of setting human
health criteria in the absence of IRIS
values for a particular chemical.
EPA requests comments on deviating
from IRIS values in deriving Great Lakes
criteria and values for the reasons
highlighted above.
5. Exposure Assumptions. , .
Today's proposed Guidance identifies
seven factors which affect an'.',
individual's oral exposure to a
chemical. Theseare: Body weight; ,
duration of exposure; recreational
exposure; drinking water consumption;
" fish consumption; bioaccumulation
factor and relative source contribution.
a. Body Weight.Today's proposed
criteria methodology, as well as existing
National criteria methodology, assume a
mean adult human body weight of 70
kg. This value is consistent with that
recommended in the EPA's Exposure
Factors Handbook (EPA 600/8-89/043,
July 1989), which is available in the
administrative record for this ••."•>• ;
rulemaking. Data In the handbook
indicate that the mean body weight of
adults is 71.8 kg on a National basis
which can be rounded to 70 kg. While
there is some evidence based on , ,
regional data isolated from the National
Health and Nutritional Examination .
Survey (NHANES H) that mean weight
may be slightly higher than 71.8 kg
within the Great Lakes basin, this data
can also be rounded down to the 7.0 kg
value. Use of a slightly lower body -
weight value will result in a slightly :'
more stringent criteria; EPA views a
rounding downidf body weight data to
be a conservative approach. EPA
requests comments on the usaof the 70
kg body weight assumption and also
-asks for comments on the issue of using
body weights of sensitive
subpopulatibns (such as children) when
a chemical's toxicity indicates a specific
subpopulation is most sensitive to .
exposures. •
b.Duration of Exposure. Today's
proposed Guidance assumes that oral
exposure remains.constant for a
lifetime. The exposure values are based
on, or consistent with, Great Lakes-
specific data. While the exposure ' .
assumptions could be over- or under-
protective for individuals who live a •
portion of their lives outside the Great
Lakes basin (in areas where their.
exposures are different), EPA believes
that it would not be practical to attempt
-to derive exposure assumptions that
would take into account the movement
of people in and out of the Great Lakes
•basin. EPA believes it is reasonable to
derive criteria based on exposures of
those individuals living their entire
lives in the Great Lakes basin. Since
.drinking water and fish consumption in
the Great Lakes is equal to or greater
than that of most other areas of the
country, the exposure assumptions
should be appropriately conservative for
most if not all individuals moving in
:and out of the.Great Lakes area. EPA
requests comments on the use of longer
lifetime exposure periods, such as 75
years instead of the currently proposed "
70 years. EPA also requests comments ,
on whether the use of shorter exposure
" periods (i.e., less than 70 years) would
be more appropriate to account for.
mobility of individuals in and out of the
Great Lakes basin. . : '
c. Incidental Exposure. Theincidental
ingestiori exposure factor relates to oral
: exposures which might occur through '•
recreational activities" in or on the water:
This factor is relatively small, and has
'not been included in the derivation of --
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20870
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
the existing National criteria. While the
contribution from recreational
exposures is estimated to be small for
the Great Lakes region based on
estimates of recreational activity in the
Great Lakes basin, EPA believes that
including the factor in today's Guidance
represents a marginal improvement over
the existing National approach. The
value proposed (0.01 liter/day) for use
In today's Guidance represents oral
exposures only, and is oased primarily
on evaluation of recreational exposure
estimates made by EPA in 1979 (U.S.
EPA, 1979, Identification and
Evaluation of Waterborne Routes of
Exposure from Other than Food and
Drinking Water, Office of Water
Planning and Standards, EPA 440/4-79-
018) and on recreational activities data
compiled by the State of Michigan.
Those data are summarized in the
Human Health TSD (Exposure
Assumptions, section ELD) which
describes in detail the basis for today's
proposal. EPA also requests comments
on whether a factor should be included
for incidental dermal exposure which
occurs through recreational activities.
EPA requests submission of any data
that could be used to derive such a
factor. Soma studios with chemicals,
such as trichloroethylene, have shown
that dermal uptake occurs in animals
exposed to the chemical in water
(Bogan, K.T., et al., 1992, Dermal
Absorption of Dilute Aqueous
Chloroform, Trichloroethylene, and
Tetrachloroethylene in Hairless Guinea
Pigs, Fundam, Appl. ToxicoL, 18:30-
39), which is available in the
administrative record for this
rulomaking.
d. Drinking Water Consumption. The
current National human health criteria
assume a drinking water consumption
rate of two liters per day. Originally,
this value was adopted from the U.S.
Army which has established that figure
as the amount needed for military
personnel ia the field. This number was
later adopted by the National Academy
of Sciences in developing drinking
\vater risk assessments (NAS, 1977.
Drinking Water and Health, p. 11.). EPA
has reviewed additional data (several
studies in different parts of the country)
on drinking water consumption which
indicates that the average adult water
consumption rate is 1.4 liters per day
(USEPA, 1989, Exposure Factors
Handbook, EPA/6dO/8-89/043).
However, the data also indicates that
two liters per day is a reasonably
conservative assumption of at least the
00th porcontila consumption value for
tho Great Lakes basin (Cantor, K.P., et al.
1987. Bladder cancer, drinking water
source, and tap water consumption: A
case control study. J. National Cancer
Institute 79(6):1269-1279). The data
from Cantor's study are taken from
several mid-west and east coast cities
and states, including Detroit and Iowa,
which are considered representative of
the Great Lakes region. EPA is
proposing that the criteria be derived -
using this 90th percentile ingestion
value of two liters per day, but requests
comment on whether selection of
another value such as 1.4 liters per day
would be more appropriate. It should
also be noted that, since the two liters
value is a conservative assumption (only
10 percent of the population drinks two
liters of water a day and considerably .
less can be expected to drink two liters
of untreated surface water) and the 0.01
liter associated with incidental exposure
is so minute, EPA presumes that two
liters per day is protective of both
drinking water and incidental ingestion
exposures for waters which may be both
a drinking water source and used for
recreation. EPA requests comments on
whether such an assumption is justified.
EPA also requests comments on whether
surface water criteria for waters
designated for drinking water uses
should assume consumption of
untreated water, as is proposed.
e. Fish Consumption. Today's
proposal includes a fish consumption
rate of 15 grams per day. This differs
from the 6.5 grams per day value which
is used in the derivation pf the existing
National criteria. The 6.5 grams per day
value represents a National average
consumption value for freshwater and
estuarine fish and shellfish, whereas the
proposed Great Lakes value represents
at least the mean exposure level for
regionally caught fish for the regional
sportfishing population. (Based on
regional population data, including
information on the number of
sportfishing licenses bought and used,
members per family, and measured fish
consumption rates, it is predicted that
approximately 90% of the entire
regional population consumes 15 grams
or less of regionally caught fish per day.)
Thus, a more conservative target
population was chosen than is used in
the National criteria methodology and
the proposed fish consumption value is
based on Great Lakes-specific statistical
data. The actual value of 15 grams per
day was derived from review of several
regional studies in. Michigan (West, et
al., 1989), Wisconsin (Fiore et al, 1989)
and New York (Connelly, et al., 1990).
The Human Health TSD (Section D—
Exposure Assumptions) provides an
analysis of these studies, and discusses
the derivation of the 15 grams per- day
value. While some of the sportfishing
. population (and other subpopulations
such as subsistence .anglers) may
consume more than 15 grams per day,
EPA believes these values are very
protective of the entire population for
the following reasons:
i. The fish consumption estimate is an
estimate of fish carrying the highest
body burden of pollutant that will be
allowed through implementation, of the
criteria. Since it is highly unlikely that
even those who eat more than 15 grains, ,
per day of all freshwater fish will eat
more than the equivalent of .15 grams
per day of maximum pollutant-bearing
fish, the consumption rate will also be
protective of the high end consumer.
ii. The proposed Guidance allows for
the use of higher fish consumption rates
and drinking water rates in developing
site-specific criteria (see section VIII. A
of this preamble) which would provide
increased protection for those particular
waters that are heavily used by
subpopulations that may not be
adequately protected by State-wide
criteria, such as certain subsistence
-anglers.
f. Bioaccumulation Factor (BAF).-The •
BAF is the ratio of the pollutant '
concentrations in aquatic organisms to ••
pollutant concentrations in the waters
in which they live. Because some
chemicals have a tendency to
accumulate in fatty tissues,
concentrations of such chemicals in
aquatic organisms can be thousands of
times greater than in ambient waters.
Today's proposal includes a
methodology for deriving BAFs, and
technical suppprt documents describing
the methodology and BAF derivation for
those chemicals for which human
health and wildlife criteria are
proposed. The preamble to the BAF
methodology discussed differences
between the proposed approach and the
existing EPA approach.
g. Relative Source Contribution.
Under today's proposed Guidance, EPA
assumes an 80 percent relative source
contribution (RSC) from surface water
pathways (water and fish) for
bioaccumulative chemicals of concern
(BCCs), and 100 percent RSC for non-
BCCs, in deriving noncancer criteria/
values. A100 percent RSC is assumed
for all chemicals in deriving cancer
criteria/values.
The existing 1980 National guidelines
assume a 100 percent RSC for all
chemicals, unless there are specific data
available on other ingestion arid
inhalation exposures. In practice, when •
calculating human health criteria, these
other exposures (ingestion and
inhalation) were generally excluded
because accurate data on these other
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993 '/ Proposed Rules
20871
exposure pathways were not available.
However, in a total exposure evaluation,
there may be exposures from food, air
and soil for a given chemical. :
.: To at least partially account for
exposures through other pathways, the
Great Lakes Technical Work Group ;•
developed a RSC for surface water;
pathways of 80 percent for
bioaccumulative chemicals of concern
(BCCs). (See the "definitions." section to
determine whether a chemical is
considered "bioaccumulative, chemical
of concern.") •
The RSG factor is based upon the
concept described in EPA's National
, Primary Drinking Water Regulations .
" 0anuary 30,1991, 56 FR 3535) where,
in the development of-maximum
contaminant level goals (MCLGs) for
drinking teter, a relative source
Vcontribution from drinking water is
assumed to be 20 percent in the absence ,
of actual exposure data, .', "-
Fo^ non-BCCs, the Great Lakes
Technical Work GrQup'.proposed a RSG
of 100 percent. The Work Group " ' .
reasoned that bioaccumulative
chemicals are those for which surface
water pathways are likely to be major
contributors to total human exposure,
' and, therefore those upon which the
surface water program should,
particularly focus in achieving pollutant
discharge reductions. For npn-
bioaccumulative pollutants, assuming
less than 100 percent RSC'could forcd
large-scale reductions in discharges that
are relatively insignificant compared to
other exposure routes. The Technical
Work Group reasoned that the other ,
more significant routes of human ,
exposure should be addressed through
other regulatory efforts, rather than
attempting to eliminate relatively
insignificant exposures via greater
control of discharges to surfaqe waters.
EPA requests comments on today's
, proposal and on possible alternatives to
.today's proposal for derivation of .
noncancer criteria and values, such asi
Providing for and/or requiring the use of
actual data, when available, to calculate
the ambient surface water exposure
contribution to the total human ! ,
exposure for both bioaccumulative and
non-bioaccumulative chemicals, in lieu
of using the proposed default approach
for nonbioaccumulatives only; the use
of 100 percent exposure from surface
water for" all pollutants; the use of a
"basement" and "ceiling" ranging from
20-80 percent when actual data indicate
the RSC is below 20 percent or greater
than 80 percent, the use of alternative
default percentages (e.g., 20-40 percent
for non-bioaccumulative pollutants and
40-^60 percent for bioaccumulative
pollutants to ensure greater protection
from unknown sources), when intake
data from other exposure routes are, not
available to characterize overall
exposure; and the inclusion of a
provision allowing flexibility in .
adjustinga calculated RSC upward or
downward depending on how much
actual total exposure from all ingestion
pathways approaches the health-based .
RAD or ADE. EPA also requests public
comment on whether, any of the options •
described in this preamble for use of an
RSC in deriving noncancer criteria and
values should be considered in
calculating Great Lakes cancer criteria ."
and values (HCVs). " ,
hi General Considerations. Although
the, methodology proposed today
provides that all adverse effects ~
(including acute and subchronic effects)
. should be evaluated in deriving an
HNV, the methodology utilizes the same
. set .of exposure assumptions regardless
,of the type of effect chosen as the basis
for criteria/value derivation. The
exposure assumptions include the 15
gram-per-day fish consumption value
and the two liter per day drinking water
value described above. These
assumptions are based on long-term
average consumption rates that are most
appropriate for use in deriving criteria
protective against long-termChronic
effects. It can be expected, for example,
that people may eat as much as one-half
to one pound (224 to 448 grams) of fish
in a single meal, and that there may be
occasions (such as on recreational
fishing outings) when such large fish
meals are consumed on a, daily basis for
several consecutive days. The two liter
drinking water consumption rate may
represent a worst-case assumption for
most people (see Exposure Factors
Handbook); however, there maybe
subpopulations, such as manual
laborers, for whom it is not. The
concern from a health standpoint is that
a human might receive a large enough
dose of a chemical from consuming a
large amount of fish or water over a
short time period to result in acute or
: subchronic tdxicity. •
Accordingly, EPA invites comment on
whether the final methodology should ;
specify a different set of exposure
assumptions for use in deriving criteria
protective of acute and subchronic,
effects. Data supporting a value other
than the two .liter per day drinking
water consumption estimate is
specifically requested. In addition, EPA
invites comment on/the possible use of
448 grams (one pound) as a reasonable
worst-case, one-day fish consumption
estimate and 2,240 grams as a,
reasonable worst-case, 10-day fish
consumption estimate (based on 10
consecutive days of consumption of
one-half pounds offish). These values
could be used hi deriving one-day and
10-day criteria/values protective of:
acute and subchronic,effects; EPA's '•••"••
drinking water program has used these
exposure periods in deriving drinking
water health advisories. EPA invites
comment, however, on.whether
different exposure periods would be-
more appropriate in deriving surface
water criteria/values. EPA also invites
comment on the possibility of requiring
the derivation of criteria/Values
addressing short-term, high level
.exposures where sufficient data exists,
and providing that .the- more stringent of
the chronic criteria/values or the acute/
subchronic criteria/values should apply
in regulating Clean Water Act
discharges.
Finally, EPA also requests comments
on the option of changing all exposure
levels such as using 1 liter/day for a
water consumption factor, a lower fish
consumption rate, and a lower duration
of exposure level, in order to,develop a
criterion exclusively developed for a
child. ; ..,: : .-••'•
6. Minimum Data Requirements/Tier I •'.
and Tier n . :
In developing today's proposal, the
Initiative Committees worked to address
a perceived shortcoming associated with
the existing 1980 Guidelines' human •
, health water quality criteria
methodology. The shortcoming involves
the need for a fairly extensive database .
before a human health criterion can be
derived and a discharge permitted.
Although a NOAEL from a 90-day study
(which is a minimum requirement of the
1980 National Guidelines in order to •
develop a noncancer criterion) does not
appear-to represent ah extensive
database to develop a Tier I criterion; a
90-day study may cost up to $120,0000
to complete and may result in even
more cost and time expenditures if
histopathology is performed on test
animals. In addition, many.90-day •
studies are preceded by range finding
Studies which add to overall time/cost .
expenditures. With regard to Tier I
cancer criteria, a long-term or lifetime
study (generally a year and a half to two
years of exposure) in a rodent is a : .
minimum requirement to 'determine
potential carcinogenicity. This extensive'
database requirement has resulted in
lack of criteria for many chemicals and
a resultant case-by-case determination
by States in order to permit a particular
chemical discharge. In'a worst case
scenario, it may have resulted in the .._-••
discharge of a particular chemical
, without consideration of health effects, •
thus potentially endangering the welfare
. of the human population in the area of :
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20872 Federal Register / Vol. 58. No. 72 / Friday; April 16, 1993 / Proposed Rules
the discharge. In other cases, the State
has regulated a poorly characterized
chemical by using a technology based
permit limit or a broad chemical
parameter such as chemical oxygen
demand (COD) or total organic carbon
(TOQ.
Generating the required criteria
development database can take many
months or years and may be very
expensive. Further, it maybe necessary
for States to quickly decide an
acceptable ambient level of
contaminants. To address this Issue, a
Her n methodology, which requires a
less extensive database [similar to the
Tier II methodology for the development
of aquatic life values), is also proposed
herein for the development of human
health values,
a. Carcinogens, The methodology for
deriving Tier I criteria and Tier E values
for carcinogens (the human cancer
values or HCVs) is identical. However,
the Tiers are distinguished by weight of
evidence, and the amount and quality of
data that is required for use in deriving
the criteria or values. The goal is to
eventually have sufficient data
developed on the Tier n chemicals to
allow development and adoption of Tier
{criteria.
Tior I HCVs are calculated for
chemicals for which data exist which
are sufficient to classify the chemical as
a human carcinogen (Group A under the
existing EPA classification scheme
described in. detail in the 1986 EPA
Guidelines for Carcinogenic Risk
Assessment (51FR 33992), or a probable
human, carcinogen (Group B). la
addition, for possible human
carcinogens (Group C), for which data
may be quantified, a Tier I criterion may
ba developed when studies have been
weU-conducted yet are limited because
they involve only a single species,
strain, or experiment which does not
demonstrate a high incidence, unusual
site or typo of tumor or early onset
Under today's proposed methodology
for Tier n carcinogens, the Group C
carcinogen data maybe used in
developing a Tier n value, where the
data are sufficient (i.e., enough data is
available to conduct a quantification,
yet is still limited based on Tier I
requirements, see section H.l of
appendix C to part 132). Readers are
referred to the Human Health TSD for a
more detailed discussion on the amount
of data neoded to conduct a
quantification.
Chemicals are classified as possible
human carcinogens (identified as Group
C under the present EPA cancer
classification scheme) for many reasons,
including the following:
1. Carcinogenicity has been
documented in only one test species
and/or only one cancer bioassay and the
results do not meet the requirements of
"sufficient evidence;"
2. Tumor response is of marginal
significance due to inadequate design or
reporting;
3. Benign but not malignant tumors
occur with an agent showing no
response in a variety of short-term tests
for mutagenicity; and
4. There are responses of marginal
statistical significance in a tissue known
to have a high or variable background
rate.
The chemicals which fell under these
four categories of Group C theoretically
may be as potent or dangerous to
humans as known human carcinogens
(identified as Group A under the present
EPA cancer classification scheme) or
probable human carcinogens (identified
as Group B under the present EPA
classification scheme) but have not been
as well or extensively tested with regard
to both human and animal studies. For
these reasons, the proposal today
requires that Tier I criteria be set for
those types of Group C chemicals which
are weU characterized and supported by
a well-conducted study. For those
Group C chemicals in which the cancer
study (or studies) indicate(s) a
significant increase of cancer in test
animals but are limited by either: a
marginal statistical correlation between
chemical and tumors due to high
control tumor incidence, a weak dose-
response relationship, or an incidence
of benign tumors rather than malignant
tumors, Tier H cancer values shall be
derived. If a cancer quantification
cannot be conducted due to lack of data
(number of test animals, and or only one
dose group of animals has responded,
making it impossible to determine a
slope factor) then the chemical must be
assessed on a noncancer basis and a Tier
I or n criteria or value (HNV) should be
developed, if available data exists. An
option, which EPA requests comments
on, is whethe? a Tier n value could be
set for an unquantifiable Group C
chemical. For instance, benign tumors
or other precursors to malignant tumors
such as hyperplastic nodules or
peroxisome proliferation could be
quantified (in the cases of benign
tumors) or used as a sensitive pre-cancer
endpoint to set a value.
The proposed Great Lakes Guidance
differs from the existing 1980 National
Guidelines, in that all possible
carcinogens (Group C) are not being
treated similarly. The 1980 National
Guidelines required the development of
criteria based on cancer, risk levels of
10 ~5 to 10~7 for all Group C
carcinogens. Today's proposal is
distinguishing Group C carcinogens by
the amount of data present and the
ability to'quantify the cancer risk.
In addition, the Great Lakes proposed
Guidance differs from the policies of
some parts of EPA with regard to its
treatment of Group C chemicals. Under
the Safe Drinking Water Act, for Group
C contaminants, the Maximum
Contaminant Level Goal (MCLG) is
usually based on the RfD approach
when sufficient non-carcinogenic data
are available. An additional one-to-ten
fold safety factor is used to account for
possible carcinogenicity. The resulting
MCLG can then be compared to a MCLG
derived using a cancer risk assessment
approach if the cancer data are
quantifiable. These comparisons are
made to ensure that there are no large
discrepancies in the numbers derived
using both approaches. To date, no large
discrepancies have occurred. If adequate
data are not available to determine an
RfD, then the MCLG is set at the 10'~ s
to 10 ~6 excess cancer risk level where
such quantification is appropriate.
EPA under the Federallnsecticide,
Fungicide and Rodenticide Act (FIFRA)
examines the risk for Group C
contaminants using both an RfD
approach and quantification of cancer
risk using the cancer potency. When
using the RfD method, EPA does not
add an extra uncertainty factor to
account for possible carcinogenicity in
its application of FIFRA. However, EPA
does limit the use of the chemical (i.e.,
cannot be used as a food additive) when
derived under the RfD method. Either
method may be an appropriate method
for risk management decisions,
EPA specifically requests comments
on: the procedures proposed today for
derivation of Tier I criteria and Tier E
values for possible carcinogens ("Group
C"); and the alternative of using an
additional uncertainty factor (up to 10)
on a noncancer endpoint for Group C
chemicals to provide protection from
•possible carcinogenicity (a HNV
calculated with an extra UF of 10 to
protect against possible carcinogenicity
would result in protection from both
cancer and noncancer endpoints); and
the alternative of deriving criteria and
values for Group C only through
noncancer assessments without an
added uncertainty factor for possible
carcinogenicity.
b. Non-carcinogens. For non-
carcinogens, there is also a distinction
between Tier I and Tier II. Human ,
Noncancer Values (HNVs) for the Tiers
are again distinguished on the basis of
the available database. All relevant and
available data must be considered. The.:,
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Federal Register- / Vol. 58, No. 72 / Friday, April 16,, 1993 / Proposed Rules
20873
minimum acceptable data base for
derivation of a Tier I criterion is at least
one.well conducted (see section; IT of the
Human Health TSD—Minimum Data
Requirements, Appropriate Study
Design and Data Development, for a
discussion of a ''well conducted study")
subchronic mammalian study. The
^duration of the study must be at least 90
days in rodents, or 10 percent of the ,
lifespan of other appropriate species.
The'studies ideally should establish a
dose response, i.e., a frank-effect level
(PEL)—a level at which severe adverse
effects or death occurs—as well as a
LOAEL and NOAEL; Generally, the .
minimum data point used for decision
making is a NOAEL; however, onev
exception to the requirement of ising
only a NOAEL is the use of a LOAEL
involving mild, reversible effects, which
may be considered acceptable from
longer term studies where a NOAEL ,
may not be available. (For example, a
slight decrease in body weight may be
considered a minimal LOAEL 01 '
possibly a NOAEL depending on other ,
observed effects in a study, and whether
the effects can be linked to the chemical
!". in question.) •
For Tier n values, as with Tier I
criteria, all relevant available data must
be considered. In developing Tier n
values, the absolute minimum ;
acceptable database is a well conducted
repeated dose mammalian study of at
least 28 days. The 28 day study was
chosen as a minimally acceptable test
that can yield sufficient information
upon which to derive a Tier n value. It
is also' a study length used by the
Organization for Economic Cooperation
and Development in their guidelines for
testing the safety of chemicals and by .
EPA's Office of Prevention, Pesticides
and Toxic Substances to evaluate
toxicity of chemicals. In some cases, the
' most critical effect of a chemical will
take place well before a 90 day exposure
that is, the acute effects of the chemical
are of greatest .concern. When high
• levels of a chemical over a short-term
exposure can cause adverse effects, the
results of a 90 day or longer-term study
at low doses may riot identify the .-•
critical acute effect identifiable after an
acute high-dose test. In these cases, even
in deriving a Tier I criteria, the most
sensitive endpoint must take
precedence over a less stringent 90 day
test result. -,..."
Results from short-term studies can be
correlated to longer-term study results,
albeit to a limited degree (Weil and
McCollister, 1963, Relationship /
Between Short- and Long-Term Feeding
Studies in Designing an Effective
Toxicity Test, Agricultural an Food ,
Chemistry. 11(6): 486-491). Weil and .
McCollister were able to predict
minimal effect levels for tworyear ,
exposures from short-term test results. :
Their assessment was not endpoint-
specific, but rather correlated to the
ratios between duration and any adverse
effect. •; ,
Again, in using a 28 day study, the
study should ideally produce a dose -
response curve, including a FEL,
LOAEL and NOAEL. (EPA ,
acknowledges that in many studies only
a LOAEL and NOAEL will be observed, ,.
and in some cases only one or the
other.) However, the minimum
acceptable data point for decision
making on such short term exposure
data must be a NOAEL. In addition, the
study ideally should be designed to
observe all possible systemic effects and
include examinations for \
histopathblogy. EPA does not believe
studies which just.examine behavioral
changes or body weight changes would
be acceptable as the basis for developing
a Tier n value. Data from studies of ..'.'"
longer duration (greater than 28 days)
and LOAELs from such studies may be
more appropriate in some cases for
derivation of Tier n values. Use of a
particular LOAEL should be supported
by the following information: Severity
of effect, quality and duration of the
study. EPA does not want-to preclude
the use of LOAELs from studies slightly
longer than the required 28 day studies
(such as 30 day tests) if the LOAEL from
such a study represents an effect which
is mild, reversible, close to a probable
or actual NOAEL, and representative of
effects observed over chronic exposures.
When the Tier n methodology is used
to derive a HNV, an additional
' uncertainty factor of up to .10 maybe
applied in deriving the ADE. This factor
is intended to account for the
•'• difficulties in extrapolating from a short
term NOAEL to a long-term NOAEL.
Structure activity relationships (SARs),
and all other available data on the'
chemical should be used to determine .
the appropriate additional uncertainty
factor. An SAR compares a chemical
with substances that have structural
similarities in order to predict whether
the chemical might cause similar toxic
. effects. The EPA Office of Prevention,
Pesticides and Toxic Substances has
developed an SAR approach for
assessing the hazards of chemicals for
which very little data exist. For details
on this EPA approach, refer to .two
journal publications: Auer, C., J.
NabholzandK. Baetcke, 1990, Mode of
Action and the Assessment of Chemical
. Hazards in the Presence of Limited Data:
Use of Structure-Activity Relationships
(SAR) under TSCA, Section 5, Environ.
Health Persp., Vol. 87, pp. 183-197; and
Auer and Gould, 1987, Carcinogenicity
Assessment and the Role of Structure
Activity Relationship (SAR) Analysis
under TSCA Section 5, Envir. Carcinp.
Revs. (J. Enviro. Sci. Hlth.) C5(l), 29-71.
, The issue; of whether to propose a Tier
H HNV human health methodology was
one of considerable debate within the
Initiative Committees. In particular,
there was concern that use of a 28 day,
or other subacute study with the'use of
additional uncertaintyfactors, may
result in underprotective values, since
such short-term studies typically do not
reveal evidence of other possible •
adverse effects resulting only from
longer-term exposure. EPA requests
comments on this issue. EPA also
requests comments on whether the use
of a Tier n human health methodology
is appropriate and on the specific
approach proposed in today's notice. .
EPA is particularly interested in other
: possible and practical Tier n
methodologies, or in practical options to
the use of a Tier II methodology to
address lack of optimal well-developed'
databases. Finally, EPA invites,:
comment on whether or not even
shorter term studies, such as 14 day
studies, might effectively be used in a'.'•.-.'
Tier n HNV approach. , -
EPA is now conducting research on
the correlation of short-term study
results to long-term chronic test results.
This research will entail an extensive
'evaluation of several scientific databases
which include 14 day, 28 day, 90 day
and two year study results. Data from
these studies will be analyzed ;
qualitatively and quantitatively (a
number of options are being explored, .'.
such as categorical regression, analyses.
or analyses of ratios or specific
endpoints) to determine if shorter-term
study results will adequately predict
toxic effects associated with long-term
exposures. For example, one proposed
option is to'divide 28 day NOAELs (or
LOAELs) by a duration scaling factor to
obtain a corresponding chronic value
, and then apply an appropriate ;
uncertainty factor. These results could
then be compared to short-term and
long-term data for other chemicals to
" validate the predicted outcome of a
particular model. . . -
If the findings of EPA research appear
relevant to today's proposed Tier H
methodology, EPA expects to issue a
notice of availability of the results of
this research for consideration by^the
public in commenting on today's rule.
One option which EPA is considering
as an alternative qr.supplement to'the
proposed Tier II approach is to screen .
a chemical initially using EPA's SAR
evaluation approach (see Auer, C., J.
Nabholz arid K. Baetcke, 1990, Mode of
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20874
Federal Register / Vol. 58, No. 72 /^Friday, April 16, 1993 /Proposed Rules
Action and the Assessment of Chemical
Hazards in the Presence of Limited Data:
Use of Structure-Activity Relationships
(SAR) under TSCA, Section 5, Environ.
Health. Porsp. 87:183-197. EPA requests
comments on other methods of
conducting SARs. The SAR approach
would ba used to determine whether a
related chemical could serve as a
surrogate for the chemical for which
there Js little or no data. This approach
could he used to either set a Tier II
value based on surrogate chemical data
or to justify further data development,
as described below. EPA requests
comments on the appropriateness of
using surrogate chemicals to develop
Tier n values.
For example, if an SAR indicates that
a chemical is somewhat similar in
structure to a class of chemicals which
are extremely toxic or potent
carcinogens, States could develop a Tier
II value if a clear surrogate chemical
existed or could be required to conduct
or require permittees to conduct
additional toxidty testing, such as the
28 day study now required by Tier n
and/or additional studies on
reproduction, neurotoxicity, or even
longer-term studies as if a surrogate
could not ba identified. The intent of
this alternative Tier n approach would
be to require testing only for those
chemicals of concern for which a
surrogate cannot be determined and to
avoid unnecessary testing for chemicals
of very low health concern, as indicated
by SAR. EPA requests comments on the
feasibility and on the scientific merit of
such an alternative option.
7. Criteria Derivation
The Tier I human cancer criteria or
Tier n value is calculated as follows:
HCV =
RADxBW
WC+(FCxBAF)
Whero:
HCV=Huinan Cancer Value in
milligrams per liter (mg/L).
RAD=Risk associated dose in
milligrams toxicant per kilogram body
weight per day (mg/kg/day) that is
associated with a lifetime incremental
cancer risk equal to 1 hi 100,000.
BW=Body weight of an average
human (BWs70kg).
WC=average per capita water
consumption (both drinking and
Incidental exposure) for surface waters
classified as public water supplies '
(WC
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Federal Register /Vol. 58, No, 72 I Friday, April 16, 1993 / Prpposed Rules
20875
proposal that differs from the current
National guidelines.
D. Comparison With the Clean Water
Act and Great Lakes Water Quality
Agreement
As mentioned earlier in section ffl.D
(Aquatic Life), the CPA states that the
proposed Guidance shall be no less
restrictive than the provisions of the.
Glean Water Act and National Water
Quality Criteria and Guidance. The CPA
also specifies that the Guidance is to _
.conform with the objectives and
provisions of the Great Lakes Water.
Quality Agreement. The discussion
below addresses coriformance of the '".'.
. -proposed human health methodologies
and criteria with these requirements.
1. Tier I Human Health Criteria/| :
Methodology .
, a. Comparison With the Clean Water
Act. Under the authority of section
304(a)(l) of the Clean Water Act, EPA
established the 1980 National
Guidelines, to be used in deriving
National human health criteria. EPA
believes that although today's proposed
Tier I,human health criteria ;
methodology and the criteria proposed
thereunder are not identical to the 1980
National Guidelines and individual
National criteria in all details, they are
generally no less restrictive.
First, as discussed above in this
section of the preamble, EPA is ,
proposing in today's notice Tier I
human health criteria for 20 pollutants
for which National criteria exist. These
.pollutants include a broad section of -
chemicals of concern proposed by the
Initiative Committees to test the
proposed methodology. Although
today's proposal includes only these 20
pollutants while National human health
criteria are currently available for over
90 pollutants, EPA believes that this .""
approach will not result in less stringent
levels of control. This is because under
the implementation .scheme proposed
today, Great Lakes States would be ''
required to derive criteria and values for
'... these pollutants and for all other
pollutants except those listed in Table 5
of part 132 whenever sufficient data
exist to meet Tier I or Tier H minimum
data requirements and the State
. determines that it is necessary to control
these pollutants. Thus, the scope of the
proposal in terms of pollutants covered
> is actually broader than the.current
National Guidance. ,
Furthermore, because the Tier I
criteria for human health proposed
today assume a, higher fish consumption
rate than the National criteria arid use
BAFs rather than BCFs to calculate fish
tissue residues, the proposed numeric
criteria 'are equivalent to or more
restrictive than the current National -
criteria, with one exception. The :
proposed drinking water criterion for ,
cyanide is slightly higher (i.e., less
stringent) than the Nationalcyanide
criterion. The proposed cyanide Tier I
human health criteria for drinking and
nondrinking waters are based only on
npncancer effects. Although both
today's proposed cyanide criteria and
the National cyanide criteria are based
bri the same study, there.is a small
difference between the criteria due in
part to the different fish consumption
rate and in part to rounding of the ADE _
and the criterion itself. EPA requests
comment on the option of promulgating
the drinking water National criterion for
cyanide.
Additional Guidance provisions and
measures will further enhance
consistency with the Clean Water Act.
Specifically, EPA is proposing
elsewhere in today's Guidance a
procedure to review State-calculated .
Tier I criteria for consistency with the
Tier I methodology. In addition, the
proposed Guidance contains a
requirement for State adoption as ;
standards of any Tier I criterion that
EPA publishes in the future. Thess
provisions are intended to ensure
consistency with the Clean Water Act
and to promote consistency in
regulation throughout the Great Lakes
System, ~;-
la. Conformance With the Great Lakes
Water Quality Agreement. For the
reasons stated hi section IH.D (Aquatic
Life) of this preamble, EPA believes that
today's proposal conforms to the""
General Objectives of the Agreement
regarding the elimination or reduction
of discharges into the Great Lakes
System. For the 20 pollutants for which
Tier I human health criteria are being .
proposed in today's notice, the ,
Agreement does not specify numeric
water quality criteria for the protection
of human health. The Agreement does
specify levels in the edible portion of
fish that should not be exceeded for the
protection of human consumers of fish
for heptachlor/heptachlor epoxide and
lindane. :
As stated earlier, EPATjelieves that
the Guidance criteria and methodologies
proposed herein should serve as a basis
to amend and supplement the Great
Lakes Water Quality Agreement, as
• proposed by the Initiative Committees.
2. Tier H Criteria Methodology .. •:
a. Comparison With the Clean Water
Act. EPA's current guidance and
regulations for water quality standards
contain nothing directly analogous to
the two-tier approach proposed today
for human health. States currently have
very broad discretion when regulating
pollutants that are subject only to
narrative criteria. EPA believes that
today's proposal is more rigorous than ;
the current National requirements in •
this area because the proposed Tier II'
method derives generally more
conservative values for non-cancer - -• • .
criteria to compensate for greater ••-••"
.uncertainty in the database. Based on
studies done to date, EPA expects that
Tier H values "will be more stringent
than existing standards for these
pollutants in most cases. Further, this
approach imposes a structure to the
process of translating narrative criteria
into numeric values. Finally, today's
approach will result in more uniform
control of pollutants lacking National
standards in the Great Lakes States.
b. Conformance With the Great Lakes
Water Quality Agreement. EPA believes '
that the Tier H methodology is
consistent with the General Objectives
of the Agreement..Moreover, it serves as
a translator mechanism of the Spates'
narrative water quality standards. The
Tier n methodology will enhance
regulatory efforts in the Great Lakes
basin, will serve its purpose of
promoting consistency in the regulation
of toxics in the Great Lakes basin, and
is therefore also in conformarice with
the Agreement. •.•._-' '
E. Review of the GreaiLakes Guidance
by the EPA Science Advisory Board
(SAB) , ..'.-"..
The SAB reviewed the Human Health
proposal for the Great Lakes Guidance
presented today. Their complete
findings and opinions are reported in an
EPA document entitled, "An SAB
Report: Evaluation of the Guidance for .
the Great Lakes Water Quality
Initiative", EPA-SAB-EPEC/DWC-93-
005, December 1992, which is available
in the-administrative record for this
rulemaking. '
The SAB commented that the tiered
approach offers a mechanism for.
improving EPA's data base to reduce
uncertainties and to develop
appropriate data for GLWQI compounds
for which National criteria do not exist.
EPA agrees with this comment. The
intent of the two-tiered approach was to
develop water quality standards and
permit values for chemicals of concern
and to also promote the development of
data needed to complete data bases in
developing criteria. ,
The SAB also commented that the
tiered approach has the potential to be .
frivolously applied to chemicals
regarded as safe. EPA believes that if the
proposed Great Lakes Guidance were
applied literally, without applying basic
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20876
Federal Register / Vol. 58, No. 7~2 I Friday, April 16, 1993 /Proposed Rules
toxicologic judgement, there is the
potential for misapplication. However,
the Oared approach is being applied to
chemicals which are considered
hazardous in the basin, of which there
are approximately 140. It is unlikely
that criteria will be developed for
chemicals such as sugar or fatty acids.
In addition, the Great Lakes Guidance
does not establish a rule that criteria
will be developed for all chemicals for
which data exist. Criteria or values are
to be developed for the list of 140 which
are deemed "chemicals of concern" in
the Great Lakes basin.
Additionally, the SAB noted that it is
not possible to argue that Tier I
chemicals protect against reproductive/
developmental or carcinogenic
endpofnts because the minimum data
baso doss not require data appropriate
to estimate such nazards. EPA's
response is that it is true that the Tier
1 requirements do not require, at a
minimum, all data for all possible
effects. However, the goal of Tier I is to
evaluate all available data before
developing a HNV or HCV. In addition,
the Groat Lakes Guidance attempts to
track very closely with established EPA
cancer and noncancer guidelines for
evaluating data and establishing safe
daily levels. Presently, if the only
existing data is noncancer, subchronic
data (0.g,, 90 day study), EPA allows
development of an RfD as long as
uncertainty factors are used to
compensate for lack of reproductive/
developmental data.
The use of uncertainty factors does
not take the place of well-run
reproductive/developmental studies. It
merely assumes that if a reproductive
study was conducted it may result in a
slightly lower NOAEL or LOAEL.
Henca, the practice of using an extra
uncertainty factor of 3 for lack of
reproductive/developmental data by the
RID work group.
With regard to an adjustment in Tier
I for a lack of carcinogenic data, Tier I
cancer criteria are only developed if the
chemical is considered a Group A, B, or
C carcinogen by EPA's CRAVE group.
When there is a lack of carcinogenic
data, a Tier ft value may be developed
if tho chemical is considered a Group C
carcinogen and enough data is available
to develop a ql*.
Placing a chemical lacking in
reproductive/developmental and/or
carcinogenic data in Tier H may help to
generate such data but would also
present an inconsistency with
previously promulgated EPA drinking
water standards. Many compounds
regulated under the Safe Drinking Water
Act aro Group D chemicals: Not enough
data available to make a carcinogenicity
evaluation. EPA acknowledges that it is
important to strike a balance between ;
the need to regulate a chemical, if it is
regarded as a human health concern,
and the need to complete the
toxicological data base for a particular
chemical.
The suggestion that well-
characterized Group C chemicals that
arguably do not pose a cancer threat be
regulated on a noncancer basis is an
option which has been raised in the
GLWQI proposal.
The SAB further stated that conflict
may arise if criteria are developed for
disinfectants and disinfection by-
products. EPA realizes there are
potential conflicts related to the
regulation of chlorine and chlorinated
by-products. However, if disinfection
by-products are toxic to humans,
aquatic organisms and/or wildlife, then
industrial or municipal discharges of
chlorine, chloramines or by-products
should be controlled by Great Lakes
Initiative criteria. In many cases,
disinfection of wastewater may be
necessary to maintain a use designation
(e.g., swimmable). However, if
chlorination results in the loss of fish,
wildlife and a fishable use designation,
the reduction of chlorination by-
products will be required through
GLWQI criteria. Clearly, a balance will
have to be struck in the development of
criteria which serve as the basis for
conflicting designated uses.
The SAB also commented that the
GLWQI Guidance may conflict with
existing National guidelines and
criteria. EPA acknowledges the potential
for confusion. In reviewing and revising
the 1980 methodology for developing
human health criteria, EPA is closely
examining the requirements of the
GLWQI. However, it must be noted that
the GLWQI Guidance is based on the '
combination of basic National
methodology guidelines for conducting
risk assessment with regional exposure
assumptions.
With regard to thresholds for
carcinogens, the SAB stated that the
method by which low dose
extrapolation is conducted should not
be viewed as simply threshold or
nonthreshold carcinogens. Mechanisms
of action should be considered. The
Human Health TSD presents text from
EPA's 1986 cancer guidelines which
recommends the evaluation of
mechanistic cancer and
pharmacokinetic data in assessing
carcinogens and models to be used in
quantifying the potency. The TSD
includes a level of subtlety with regard
to carcinogenicity not present in the
regulation and preamble.
Further, the SAB noted that with
regard to a Minimum Data Base, Tier I
and II .should develop separate values
for Group C chemicals depending on thrv
available data. Tier I should only be
reserved for Group C chemicals which
have been adequately tested and which
do not support the notion that they are
probable human carcinogens. Tier n'
, should include chemicals which have
been tested in only one species. EPA's
response to this comment is that the
GLWQI Guidance allows for the
development of Tier I or II values for
Group C chemicals depending on the
available data. The distinguishing
factors focus on whether enough data
exist to conduct a potency estimate and
whether a dose response actually exists.
To restrict Tier I to only those chemicals
which have been adequately tested may
be too limiting and may ultimately
result in under protecting human
health. EPA acknowledges that there
may be cases where a chemical is so •
well tested that it does not appear to be
a possible human carcinogen. To
address this situation, EPA has
proposed the option of regulating some
Group C chemicals using a noncancer
endpoint with an additional uncertainty
factor to account for possible
carcinogenicity.
Another SAB comment states that
with regard to the Tier II concept, a 28
day test may not detect some human
health effects especially for chemicals
with long latency periods. EPA realizes
the use of a 28 day NOAEL may be
marginal for detecting some chronic
human health effects and is conducting
research in this area over the next year
to determine whether the 28 day data
are a reliable minimum data point. EPA
is also restricting the development of
Tier n values to results of 28 day studies
which have examined systemic effects
and ideally provided some
histopathological examination. • . .
The SAB also commented that with
regard to the use of a Relative Source
Contribution, an 80 percent RSC is not
supportable because it is within the
rounding error on the calculations of the
overall exposure. In addition, other
sources should already be compensated
for in the calculation of fish
consumption. EPA's response to this
comment is that the use of an RSC was
incorporated to account for other
sources that may contain the chemical
besides fish. In the case of pesticides,
for example, many agricultural or dairy
products may contain a pesticide in
quantities large enough to make the RSC
concept important. It is true that the 80
percent may be within the rounding
error for the calculation of the overall .
exposure, but the intent was to redu ^o
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Federal Register /Vol. 58, No. 72 /; Friday, April 16, 1993 / Proposed Rules
20877
the criteria by 20 percent in the case of
a bioaccumulatiye chemical. In essence,
the 20 percent reduction serves as a
safety factor to protect against other
possible sources of the chemical which
have not been explicitly accounted for.
This is the same process (setting a :
default RSC of 20 percent when data on
other sources does not exist) which is -
done in developing drinking water
standards, which has been approved by
the SAB in its review of drinking water
standards. . ; :
F. Literature Citation? ; .
.The following documents were
referenced in the sections above. These
documents are available in the -
administrative.record for this
rulemaking. ; :~~ ' ,
Auer, C,; and D.Gould. 1987. , ...'..'
Carcinogeriicity Assessment and the Role of .
Structure Activity Relationships (SAR)
Analysis under TSCA Section 5. Envir.
Carcino. Revs. (J. Enviro. Sci. Hlth.) C5 (1)
. 29--71. -
Auer, C., J. Nabholz and K. Baetcke. 1990.
Mode of Action and Assessment of Chemical
Hazards in the Presence of Limited Data: Use
of Structure-Activity Relationships (SAR)
under TSCA, Section 5. Environ. Health"
Persp. Vol. 87, pp. 183-197. ,
, Bogen, K.T., B,W. Colston, Jr., and L.K.
Michieao. 1992. Dermal Absorption of Dilute
Aqueous Chloroform, Trichloroethylene, and
Tetrachloroethylene in Hairlee Guinea Pigs.
Fundam. Appl. Toxicol, 18:30-39. ,
Calabrese, E.J. 1985. Uncertainty factors
and interindividual variation. Reg. Toxicol.
Pharmacol. 5:190-196.
Cantor, K.P., R. Hoover, P. Hartage, 1987.
Bladder Cancer, Drinking Water Source, and
Tap Water Consumption: A Case Control
Study. I, National Cancer Institute.
79{6):1269-1279,
Connelly, N.A.,T.L; Brown and B.A.
Smith, 1990, New York Statewide Angler
Survey, 1988, "New York State Department of
Environmental Conservation, Albany, NY.
Crump, K.S., D.G. Hbel, C.H. Longley and
R. Peto. 1976. Fundamental Carcinogenic >
Processes and Their Implications for Low
Dose Risk Assessment. Cancer Res. 36:2973-
2979.
Dourson, M., and J. Stara. 1983. Regulatory
History and Experimental Support of
Uncertainty (Safety) Factors. Regulatory
Toxicology and Pharmacology. 3:224-238.
Doursbn, M.L., L. Knauf and J.C. Swartout
1992. On reference dose (RfD) and its
underlying tpxiclty,data base.'(In press). ,
'-. Dourson, M.L-. 1993.- Modifying uncertainty
factors for noncancer endpoints. Advanced
Topics in Risk Assessment. Society of
Toxicology Annual Meeting, New Orleans,
, March 14,1993".
Fiore, B.J. et al., 1989. Sport Fish
Consumption and Body Burden Levels of
Chlorinated Hydrocarbons: A Study of
Wisconsin Anglers, .Archives of
Environmental Health, 44:82-88. ;
Hartley, W.R. and E.V. Ohanian. 1988. The
use of short-term toxicjty data for prediction
of long-term health effects. Trace'Substances
in Environmental Health—XXII, D.D.
Hemphil, Ed. University of Missouri,1 p. 3-12.
Hattis, D., L. Erdreich and M. Ballew. 1987.
Human variability in susceptibility to toxic
chemicals—A preliminary analysis of
pharmacokinetic data from normal
volunteers. Risk Anal. 7(4): 415-426.
Hattis, D. and S. Lewis. 1992. Reducing
uncertainty with adjustment factors. The
Toxicologist. 12(1):23 Abstract 1327.
Howa, R.B..K.S. Crump and C. Van
Landingham. 1986. Computer Program to
Extrapolate Quantitative Animal Toxicity
Data to Low Doses. Prepared for EPA under
subcontract #2-251Ur2745 to Research
Triangle Institute.
International Agency for Research on
Cancer (IARC). 1987. LARC Monographs on
the Evaluation of Carcinogenic Risks to •.
Human, Preamble, Final Draft, January, 1987.
World Health Organization, Lyon, France.
Lewis, S.C., J.R. Lynch and A.I. Nikiforov.
1990. A new approach to deriving
community exposure guidelines from no-' "
observed-adverse-effect-levels. Reg. Toxicol.'
Pharmacol. 11:314-330. .-_" '
National Academy of Sciences. 1977.
Drinking Water and Health. Vol. 1. National
Academy Press, Washington, DC.
Renwick, A.G. 1991. Safety factors and .
establishment of acceptable daily intake.
Food Additives and Contaminants. 8(2): 135-
150.
Renwick, A.G. 1993. D,ata derived safety
factors for the evaluation of food additives
and environmental contaminants. (In press).
Travis, C.C.fand R.K. White. 1988.
Interspecies Scaling of Toxicity Data. Risk
Anal. 8:119-125. : .
U.S.Environmental Protection Agency,
1980. Water Quality Criteria Availability,
Appendix C Guidelines and Methodology
Used in the Preparation of Health Effects
Assessment Chapters of the Consent Decree
Water Quality Criteria Documents. Federal "
Register, Vol. 45, November 29,1980, 79347-
79357.
U.S. Environmental Protection Agency.
1986. Guidelines for Carcinogen Risk
Assessment. Federal Register, Vol. 51, No.
185, Septgaiber 24,1986,33992-34002.
U.S. Environmental Protection Agency. ;
1986b. Guidelines for the Mutagenieity •
Assessment Federal Register, Vol. 51, No.
185, September 24,1986, 34006-34012.
U.S. Envh-onmental Protection Agency. -
1987. IRIS. Support Documentation.
Environmental Protection Agency/600/8r86/
32a. • . : , • : ..'.-• -•-
U.S. Environmental Protection Agency. „
"1989a. Exposure Factors Handbook.
Washington, DC, Office of Health and
Envh-onmental Assessment, Exposure
Assessment Group. EPA/600/8-89/043.
U.S. Envh-onmental Protection Agency.
1989b. National Primary and Secondary
, Drinking Water Regulations, Proposed Rule.
Federal Register, Vol. 54, No. 97, May 22,
1989, p. 22069. ; ... ,
U.S. Environmental Protection Agency. "'
1989c. Proposed Amendments to Agency
Guidelines for Health Assessment of Suspect
Developmental Toxicants. Federal Register,
Vol. 54, p. 9386, March 6,1989.
U.S.. Environmental Protection Agency.
1991. Proposed Amendments to Agency „
Guidelines for Health Assessments of ; ,
.Suspect Developmental Toxiqants. 56 FR
63798 (December 5,1991).'
U.S. Environmental Protection Agency.
1991, Amendments to the Water Quality '
Standards Regulation to Establish the •
Numeric Criteria for Priority Toxic Pollutants
Necessary to Bring All States into
Compliance with Section 3Q3(c)(2)(B).
Federal Register, Vol.- 56, November 19,
1991,58420-58378.
U.S. Environmental Protection Agency.
1991. National Primary Drinking Water
Regulation—Synthetic Organic Chemicals
and Inorganic Chemicals. Federal Register,
Vol. 56, January 30,1991. , '.
U.S. Environmental Protection Agency. -.'
1992.,Draft Report: A Cross-Species Scaling
Factor for Carcinogenic Risk Assessment '
Based on Equivalence of Mg/Kg3'4 Day. 57 FR
24152, June 5,1992. '
U.S. Envuxjnmental Protection Agency. •
1992. Reference Dose: Description and Use hi .
Health Risk Assessment. IRIS. Online: Intra-
Agency Reference Dose Work Group, Office
of Health and Environmental Assessment,
ECAO, Cincinnati, OH.
Weil, C., and D. MeCollister. 1963.
Relationship .Between Short- and Long-Term
Feeding Studies hi Designing, ah Effective
Toxicity Test. Agricultural and Food
Chemistry. 11(6):486-491; •
' West, P.C., etal. 1989. Michigan Sport
Angler Fish Consumption Survey: A Report
to me Michigan Toxic Substance Control
Committee, University of Michigan Natural
Resource Sociology Research'Lab. Technical
Report #1, Ann Arbor, Michigan, MDMB
Contract #87-20141. '•-"•••'.'
Zielhuis, R.L. and F.W. van der Kreek.
1979.-The use of a safety factor hi setting
health based permissible levels for ' ~.
occupational exposure. Int. Arch. Occup.
Environ. Health. 42:191-201,
,VI. Wildlife
A. Introduction ' .._-"'•' '
For the purposes of the proposed
Great Lakes Water Quality Criteria
Guidance, "wildlife" is defined as
species in both Taxonomic Classes,
Aves and Mammalia (birds and
_ mammals). The proposed Guidance for
deriving wildlife criteria and values is
included in appendix D of the proposed
Guidance. The Technical Support
Document for Wildlife Criteria is an
appendix to this preamble. The actual,
criteria documents which provide the .
data and the derivation of the individual
criteria are available'in the
administrative record for this
rulemakihg. EPA's expectations for
determining whether a State's water ,
quality standards are consistent with the
Guidance are set forth in § 132.6 of the
proposed Guidance.
In the case of toxic chemicals;
terminal predators such as otter, mink,
gulls, terns, eagles, o'spreys and
kingfishers are at risk from !••; .' ,
contaminants in Great Lakes waters, to
addition to direct exposure via drinking
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20878 Federal Register / Vol. 58. No. 72 / Friday, April 16, 1993 / Proposed Rules
tho water, species at higher trophic
levels are exposed to toxic substances
through the food wob as the chemicals
proceed upward via biomagnification.
Contaminants which are almost
undotectable hi lake water may be
magnified hundreds of thousands of
limes within the flesh offish and
magnified still further in a carnivorous
bird or mammal which consumes
contaminated fish out of the Great
Lakes.
Because wildlife species are at the top
of the food web, current criteria derived
to protect fish, which live in the water,
may be inadequate to protect high-level
wildlife consumers of contaminated
fish. Wildlife are especially at risk from
chemicals which biomagnify because
they era frequently exposed to very high
levels of the contaminants since they
redde at the apices of aquatic food
webs. For this reason, emphasis was
placed on selecting piscivorous wildlife
spades (i.e., those which eat fish) for
the derivation of wildlife criteria as
representative of species likely to
experience significant contamination
through an aquatic food web. Wildlife
species may also have unique metabolic
pathways which make them more
susceptible to the toxicity of a chemical
than aquatic species.
Research on wildlife species resident
In tha Great Lakes indicates that wildlifd
populations are threatened La areas of
high contamination by toxic chemicals. •
In the Great Lakes, reproductive
impairment of numerous wildlife
spacios has been correlated with the
presence of PCBs, DDT and its
metabolites, and other contaminants. In
the 1960s, mink fed a diet of Great Lakes
fish suffered complete reproductive
failure. Detailed laboratory investigation
revealed that the causative agent was
PCBs in Great Lakes fish. The overall
reproductive success of bald eagles is
much lower along lake shore areas of
the Great Lakes than in inland nesting
territories.
There is additional discussion locatec.
in the section I (Background) of this
preamble on the impacts of toxic
chemicals on wildlife in the Great
Lakes. Numerous studies confirm the
adverse effects of pollution on Great
Lakes wildlife and support the need for
water quality criteria formulated for
their protection. It is because of the
numerous impacts of toxic chemicals
observed in wildlife in the Great Lakes
and the inconsistencies among the Great
Lakes States and Tribes in addressing
wildlife impacts, that the Steering
Committee, Technical Work Group, and
EPA agreed there was a need for
generation of separate wildlife criteria
as a part of the Great Lakes Water
Quality Initiative (GLWQI). This
provides the rationale for proposing
specific wildlife standards in this
Guidance.
EPA has ample authority to develop
criteria and methods specifically
directed at protecting wildlife from
threats originating in Great Lakes
waters. Section 118(c)(2)(A) of the Clean
Water Act requires EPA to develop
numerical limits on pollutants in Great
Lakes waters to protect wildlife as well
as human health and aquatic life.
Similarly, provisions of the Great Lakes
Water Quality Agreement of 1978
require the United States and Canada to
protect wildlife. For example, Article HI
of the Agreement established a "General
Objective" of freeing the Great Lakes
System from substances resulting from
human activity that will adversely affect
waterfowl.
Moreover, several of the "Specific
Objectives" for individual pollutants set
out in Annex I of the Agreement also set
limits which should not be exceeded in
order to protect fish-consuming birds
and animals. These are presented as fish
tissue concentrations or water
concentrations as follows: DDT and its
metabolites in whole fish should not
exceed 0.3 micrograms per gram (wet
weight basis), the concentration of total
PCBs in whole fish should not exceed
0.1 micrograms per gram (wet weight
basis), and the concentration of total
mercury in whole fish should not
exceed 0.5 micrograms per gram (wet
weight basis). The "Specific Objectives"
which present water concentrations
which should not be exceeded for the
protection of fish-consuming birds and
animals are: the total concentration of
DDT and its metabolites should not
exceed 0.003 micrograms per liter; and
mirex and its degradation products
should be less than detection levels as
determined by the best scientific
methodology available.
Section 304(a)(l) of the Clean Water
Act also authorizes EPA to develop
criteria that protect wildlife for all
waters of the United States. As
explained in more detail later in this
section of the preamble to this rule, EPA
has not yet issued any nationally
applicable criteria targeted solely at the
protection of wildlife. Rather, EPA
incorporated consideration of wildlife
impacts into the 1985 methodology for
developing criteria for aquatic life
(Stephen, et al, 1985).
The proposed Guidance relating,to
wildlife criteria was developed as part
of the GLWQI. The Technical Work
Group and the Steering Committee are
collectively referred to within this
portion of the preamble as the
Committees of the Initiative. The
Committees of the Initiative assigned
the lead in developing an initial
proposal for deriving criteria to protect
wildlife for the Great Lakes Guidance to
the State of Wisconsin. The procedure
proposed by the Wisconsin Department
of Natural Resources was modified
through discussions in the Committees
of the Initiative and modified and
approved by EPA.
In developing the methodology for
deriving wildlife criteria for the GLWQI,
the Wisconsin Department of Natural
Resources, Bureau of Water Resources
Management, obtained scientific
guidance from participants in a one-day
workshop (the Workshop) held in
Madison, Wisconsin, November 8,1990.
Wildlife research toxicologists and
biologists representing academia, State
governments, the U.S. Fish and Wildlife
Service and EPA were invited to
participate in the Workshop.
Representatives of the regulated .
community were also present at the
Workshop.
B. Wildlife Criteria Methodology
Like the aquatic life and human
health criteria methodologies described
above, EPA is proposing a two-tiered
approach for the Great Lakes Water
Quality Guidance for Wildlife, which
will hereinafter be referred to as Tiers I
and n. EPA is proposing to require all
Great Lakes States and Tribes to apply
the methodology to derive Tier I criteria
and Tier n values, as well as the Tier I
numeric criteria proposed, to discharges
into the Great Lakes System. The •
Committees of the Initiative developed,
and EPA is proposing, a Tier H method
that is very similar to the proposed Tier
I method. However, because Tier It
values are based on a less extensive data
base than are Tier I criteria, the
uncertainty factor which accounts for
interspecies lexicological differences
(the Species Sensitivity Factor) may be
smaller than that used in deriving a Tier
I criteria. In deriving Tier II values, the
Species Sensitivity Factor may also
account for interspecies lexicological
differences across taxonomic classes.
This uncertainty factor is intended to
address any uncertainties,stemming
from the use of a less inclusive database
and its use is meant to produce Tier H
values that are conservative.
Tier n values are intended to be
conservative to encourage data
generation so a Tier I criteria can be
calculated. Although States and Tribes
have the authority at their discretion to
do so, EPA does not intend that Tier II
values will be adopted into State
standards, but, rather, will serve as a
translator mechanism for interpretation
of the State's narrative criteria (e.g., no
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Federal Register /Vol. 58, No. 72 / Friday^ 'April 16,' 1993 /'Proposed Rules
20879
toxic pollutants in-toxic amounts) and
as a basis for developing control
measures such as effluent limitations in
NPDES permits. In the future, EPA miajr
replace Tier n values with Tier I criteria.
as more data are generated.
1. Wisconsin State Wild and Domestic
Animal Criteria "
The Committees of the Initiative
chose, as the starting point for the
development of the wildlife criteria^
.•methodology, the Wild and Domestic
Animal Criteria (WDAC) approach
developed by the State of Wisconsin
(Wisconsin Administrative Code NR.
105,07,1989; Technical Support
Document for NR 105,1988), which is
available in the administrative record
for this rulemaking. A WDAC is the
lowest species wild and domestic •
animal value (WDAV) calculated using
the equation presented below. The
equation used to derive the WDAV
portrays a "model animal" as follows:
NOAELxWtxSSF
WDAV =
.where: WDAV is the wild and domestic
animal value in 'milligram's per liter
(mg/L); NQAEL is the no observable
adverse effect lever in milligrams of
substance per kilogram of body weight
per day .as derived from mammalian or -
avian studies (mg/kg-d);Wt A is the
average weight in kilograms (kg) of the
test animals; WA is the average daily
volume of water in liters consumed per
day (L/d) by the test animals; SSF is the
species sensitivity factor Which is an
uncertainty factor ranging between 0.01
and 1 to account for differences in
species sensitivity; FA is the average
daily amount of food consumed by the
test animals in kilograms (kg/d); and
BAF is the aquatic Ufe bioaccumulation
factor with units of titer per kilogram (L/
kg)- .; ;< -'..;..' '-/ - ".•-: ' . - •-..-.
2. Modifications to Wisconsin's WDAC
Procedure •
As mentioned, the proposed Guidance
: on a water quality criteria methodology ,
for wildlife is based on the State of
Wisconsin's wildlife criteria procedure.
However, the Initiative Committees and
EPA developed several modifications of
this State procedure which EPA is
proposing to incorporate into the
proposed Guidance, They include: A
requirement that States and Tribes use
specific Great Lakes species identified
by EPA as representatives of regional
wildlife species likely to experience
significant exp'osure from the aquatic
food web rather than using a "model
animal''; provisions that more clearly
define and.maTce more stringent toxicity
data requirements (i.e., a dose-response
study is- required); provisions which
allow a subchrbnip to chronic
uncertainty factor to be applied to the
NOAEL to extrapolate from subchronic
to chronic exposure lengths; and
provisions for two tiers of criteria rather
than one as under the Wisconsin
approach. A fifth modification to the
approach submitted by Wisconsin is
proposed in procedure 1 of appendix F
to part 132 of this proposed Guidance
(the site-specific modification portion of
Great Lakes Water Quality Guidance -
Implementation Procedures). Procedure
1 allows for the incorporation of an %
additional uncertainty factor into the
equation to account for intraspecies
variability in the derivation of a species-
specific wildlife criterion or value for a
species other than the representative
species proposed for general use. See
section VOL A of this preamble for a
discussion .of the additional uncertainty
factor in the proposed procedure i of
appendix F, as well as alternative text,
upon which EPA invites comment, that;
provides additional guidance to States
and Tribes. '.- ,
3. The Great Lakes Water Quality
Initiative Wildlife Criteria Methodology
The approach used in the aquatic life
criteria methodology, where the aquatic
life criterion is determined from a
statistically valid distribution of toxicity
values for a number of aquatic species,
is not currently feasible for the
derivation of wildlife criteria. This is
because there is a less extensive and
representative wildlife toxicity database
and limited information on species-
specific exposure parameters. The
wildlife criteria methodology is more
similar to that employed in the :
calculation of noncancer human health'
criteria.- .
The general procedure as well as the
requirements for developing wildlife
criteria and values are provided in
appendix D to part 132. The Technical
Support Document (TSD) provides
additional background as well as
guidance on the selection of values for
.uncertainty factors which may be used
in the derivation of wildlife criteria.
EPA believes that the States, the Tribes
and the public would benefit from easy
access to the background material
provided in the TSD because the
wildlife criteria are so new. EPA,
however, acknowledges that the TSD
repeats some of the material that
appears in the Method. EPA also is
concerned that the States, thO'Tribes
and the public may become confused
and mistakenly-believe that the TSD .
also sets out binding requirements.
Consequently, EPA is considering either
(1) combining the TSD with the Method
for publication in the CFR, or (2)
publishing-only the Method in the CFR
and distributing the TSD widely. EPA ,
invites comment on this issue. If option
(1) is pursued, EPA invites comments "
on whether there are any components of
the TSD which should not become .
binding requirements. ,
' As with the human health
; methodology, the wildlife methodology
has both a hazard and an exposure
component. The hazard component is
determined from the toxicity data for a
given pollutant and the exposure
component is determined from species-
specific exposure pdrainetefs.,
a. Parameters of the Hazard :
Component of the GLWQI Wildlife
Criteria Methodology. The Committees
of the Initiative discussed various
aspects of the hazard component of the
final wildlife criteria methodology. EPA
is proposing to adopt the ideas they ;
developed on several aspects of the
hazard component of the wildlife
method which are presented below.
i. LOAEL to NQAEL Extrapolations. In
some studies when a range of doses are
used, an effectis observed at the lowest
chemical concentration used in the'
study. The proposed Guidance proposes
to allow use of an uncertainty factor that
would permit a NOAEL to be estimated
from the LOAEL determined in such a
study. Experimental support for this
concept is referenced in the Technical •
Support Document for Wildlife Criteria
(the appendix to this preamble), as well .
as appendix A to the Great Lakes Water
Quality Initiative {GLWQI) Technical .
Support Document for Human Health
Criteria and Values, which is available
m the administrative record for this .
rulemaking. Copies are also available"
upon written requestto the address '"
listed in section Xin of this preamble.
EPA notes that use of such an
adjustment factor is permitted within
the existing human health water quality
criteria process (45 FR 79353-^79354,
November 28,1980; and 5Q FR 46944-
46946, November, 13,1985). EPA is
proposing to allow this adjusted NOAEL'
value to.be used in the derivation of
both Tier I wildlife criteria and Tier H
wildlife values. EPA requests comment
on this approach. :
ii. Subchronic to Chronic
Extrapolations. The wildlife criteria
methodology allows for application of
an uncertainty factor to adjust the ,
, NOAEL from a subchronic study to •
estimate a chronic NOAEL. Because of
toxicokinetic considerations, bioassays '
that are of insufficient duration to
encompass a significant portion, of ah
, organism's life spari or a sensitive life
• stage may underestimate hazards. EPA
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Federal Register /Vol. 58, No. 72
proposes providing the option of
considering exposure length by
extrapolating from subchronic studies to
estimate chronic impacts. As presented
In the Technical Support Document for
Wildlife Criteria (the appendix to this
preamble), the value of this term must
DO basad on the bioaccumulative
potential of the chemical, toxicokinetic
considerations, test length and available
test data. The value applied^ can range
from 1.0 to 10, adopting the 10-fold
uncertainty factor value applied in the
derivation of human health criteria as
the upper limit for the value.
Endorsement of this approach by EPA is
referenced in the Technical Support
Document for Wildlife Criteria (the
appendix to this preamble), and
experimental support for this approach
is referenced in appendix A to the
GLWQI Technical Support Document
for Human Health Criteria and Values.
EPA requests comments on the
provisions to allow for such adjustments
to the NOAEL in the derivation of
wildlife criteria.
iii. Species Sensitivity Factor. In the
derivation of noncancer human health
criteria, an uncertainty factor is applied
when extrapolating from results of long-
term studies on experimental animals to
humans. EPA is proposing to allow use
of a spades sensitivity factor (SSF)
which adjusts for the same type of
uncertainty—differences ha
lexicological sensitivity—among
wildlife spades. Specifically, it adjusts
only for differences in toxicologies!
sensitivity between the test species (the
species from which tha NOAEL is
derived) and the representative wildlife
spedos identified for protection or the
spedes identified as requiring greater
protection. (The SSF is not intended to
adjust for differences with regard to -
body weight and food and water
consumption rates between the test
spedes and representative spedes or the
spades requiring greater protection.)
Guidance in the selection of a SSF
value is provided hi appendix D to part
132 and the Technical Support
Document for Wildlife Criteria, The
discussion of an interspecies
uncortainry factor located in section C of
appendix A to the GLWQI Technical
Support Document for Human Health
Criteria and Values may also be useful
in determining the value of a SSF.
In its December 16,1992, report,
"Evaluation of the Guidance for the
Great Lakes Water Quality Initiative,"
(U.S. EPA. 1992), EPA's Sdence
Advisory Board (SAB) recommended
that the methodology for deriving
wildlife criteria incorporate procedures
that address a measure of the variability
of spedes sensitivities observed in
substance-specific studies. The
guidance provided in the Technical
Support Document for Wildlife Criteria
for determining an appropriate SSF has
been revised following submission to
the SAB for review. The current
guidance attempts to address the SAB's
concerns and requires consideration of
the amount and quality of available
studies; the diversity of species for
which data is available; known
physicochemical, toxicokinetic and
toxicodynamic properties of the
chemical; and similar data for chemicals
that operate by the same mode of action.
EPA requests comment on the guidance
provided in determining the value of a
SSF.
For Tier I criteria, the Agency
proposes that the SSF may be used to
extrapolate toxicity data across spedes
within each of the two taxonomic
classes of Aves and Mammalia. An
interclass SSF may be used for a given
chemical for a Tier I criteria only if it
can be supported by a validated
biologically-based dose-response model
or by an analysis of interclass
toxicological data, incorporating the
endpoints in question, for a chemical
analog that acts under the same mode of
toxic action.
Participants'at the Workshop
discussed the range of values for SSFs.
The Workshop concluded that, in nearly
all cases, the available toxicological data
for the determination of a SSF to be
applied in the derivation of a Tier I
criteria, or any value calculated using
the Tier I approach, would result in a
SSF within the range of 1.0 to 0.01. EPA
is proposing to require that a SSF;
outside of this range for a Tier I criteria,
or any value calculated using the Tier I
approach, must be based on sound
scientific and technical reasons and
must be accompanied by a.written
justification presenting this reasoning.
This justification should be provided to
EPA by inclusion in the State's or
Tribe's submission under § 132*5 of this
proposed rule. Use of a SSF outside of
this range is prohibited unless approved
by EPA based on its consideration of the
justification provided.
For Tier n wildlife values, EPA
proposes that the SSF may be used to
extrapolate toxidty data across the two
taxonomic classes without the strict
requirements presented above"for use hi
deriving Tier I criteria. Because of the
uncertainties associated with
performing interclass extrapolations, .
and becansa Tier n values are intended
to be conservative to encourage data
generation, the SSF applied may not be
greater than 1.0 but may be lower than
0.01. A written justification is not
required when a SSF less than 0.01 is
used in the derivation of Tier H values,
iv. Intraspecies Variability. Procedu**>
1 in appendix F to this Guidance
discusses site-specific modifications to
criteria/values and suggests the use of
an additional uncertainty factor in the
equation used to calculate Wildlife
Values. Section Vm.A of this preamble
presents a method for the use of this
additional uncertainty factor, called an
intraspecies uncertainty factor (ISF), to
adjust for intraspecies variability in the
development of site-specific criteria.
The use of this additional uncertainty
factor provides an additional level of
protection when protection of all '
individuals in a given population is
desired. The method presented in
section Vffl.A of this preamble proposes
incorporation of an intraspecies
sensitivity factor (ISF) into the hazard
portion of the wildlife value equation.
The following discussion provides more
detail on the ISF proposed in appendix
F and section Vin. A of this preamble.
The ISF is an uncertainty factor to
adjust for intraspecies toxicological
differences to protect sensitive
individuals in a population. The
National Academy of Sciences endorses
the use of a 10-fold factor to account for
differential sensitivities within the
human population (NAS, 1980). A
discussion of the experimental support
for the application of an intraspecies
uncertainty factor is provided in
appendix A to the GLWQI Technical
Support Document for Human Health
Criteria and Values. Although chronic
toxicological data for wildlife species
are relatively scarce, EPA believes that
the factor of 10 that EPA has developed
to protect sensitive members of the
human population will also protect
sensitive members of wildlife species.
EPA is proposing to allow the use of an
ISF value of 10 without requiring the
development of specific justification.
EPA is proposing to require users who
wish to use factors greater than 10 to
develop specific and detailed scientific
rationale for the factors they propose to
use. The rationale must be submitted to
EPA on request. EPA anticipates that
, users who have actual toxicological data
from wildlife.studies may be able to
justify the use of greater ISFs. EPA is not
proposing to permit the use of ISFs for
wildlife that are less than 10.
In the December, 1992 Science
Advisory Board (SAB) report (U.S. EPA,
1992), the EPA's SAB identified the
need for wildlife criteria to be
constructed so that, hi special cases,
they are able to protect the individual
rather than the population., EPA believes
incorporation of the ISF into the
wildlife criteria methodology; as
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20881
proposed in section VHI.A. of this
preamble, adequately addresses this
concern. EPA invites comment oh the .
JSF. .,...:' ', ". ' , -
v. Alternative Formula for Hazard
Component of Equation, la appendix D
to part 132, the hazard component is
represented by: • •
•The NOAEL applied in the equation
maybe: A NQAEL determined by
applying a LOAEL to NOAEL
uncertainty factor to a LOAEL; or a
NOAEL adjusted to account for
subchronic to chronic exposure
durations by application of a subchronic
to chronic uncertainty factor. In the
equation, the NOAEL may be further
adjusted to account for interspecies
toxicological differences multiplication
by of a SSF and/or intraspecies
.toxicological differences by division by
an ISF. Because of these potential
adjustments to the NOAEL which may
be carried out in the calculafdon of a :
wildlife value, in this preamble EPA
proposes a modification to Hie hazard
component of the wildlife criteria
calculation equation presented in
appendix D to part 132. Rather than
using the equation presented in .';..,
appendix D to part 132, EPAxequests ,
comment on the replacement of the
hazard portion of the equation
(presented at the beginning of this
section) with the formula presented
below; . -..-.".. •
•'-"." "-•';.". ED .''• •:• ':'•'-. ':'
UFS xUFc XUfkxUIv ,-
Where: . • '..'•;
ED=the Effect Dose in mg/kg-d for the
test species. This could be either a
NOAEL or a LOAEL.'
UFs-Uncertainty Factor for
extrapolating toxicity data across
species. Because it appears in the .
denominator, the value of this term
would be the inverse of the SSF '
described and defined in appendix D to
part 132 and the appendix to this
preamble.
DFc=Oncertalnty Factor for
subchronic to chronic exposures. The
Value of this term would be the
subchronic to chronic uncertainty factor
previously described and discussed in
appendix D to part 132 and the
. appendix to this preamble. •
nFs=Uncertainty Factor for LOAEL to
NOAEL extrapolations. The value of this
term would be the LOAEL to NOAEL
uncertainty factor discussed in
appendix D to part 132 and the
appendix totMs preamble.
intraspecies toxicologicai differences to
protect sensitive individuals in a
population. Because it appears to the
denominator above, this term would be
the inverse of the ISF proposed In
section ym.A of this preamble, and
discussed above in this section of the
preamble,
Jnmany cases, the value for these
uncertainty factors maybe one. That is,
values other than 1.0 would rarely if
ever be used for all uncertainty factors
simultaneously. However, EPA believes
that the alternative formula has the , :
advantage that it more dearly presents
the uncertainty factors employed. The
equation used to derive wildlife criteria
and values would be:
ED
, UFSxUFc
-XWt.
The terms are defined above and in
appendix D to part 132, This formula
appears more similar to that used in the
derivation of npncancer human health
criteria. EPA requests comment on the
adoption of the alternative formula in
the final Guidance.
b. Parameters of the Exposure
Component of the GLWQf Wildlife /
Criteria Methodology, la deriving
human health criteria, the exposure
estimates employed are for one species,
'Homo sapiens. The Committees of the
Initiative and EPA, however, wanted to
develop a wildlife method that would
protect a broad range of wildlife species.
There are two possible ways to
accomplish this: Estimate exposure
parameters for a hypothetical "model
animal," (the approach implicit in the
Wisconsin methodology); or select an
actual wildlife species as a
representative wildlife species. The
Committees and EPA agreed to select
representative species for the two
taxpnomic classes, Aves and Mammalia,
in order to provide a basis for;
determining an appropriate SSF and
incorporating empirical exposure
parameters where available for specific
species in each taxonomic class.
Selection of representative species
which are then used to derive criteria to
protect wildlife is a significant issue.
The criterion and selection process used
to select the representative species is
presented in section V of the Technical
Support Document for Wildlife Criteria
(the appendix to this preamble). The
species selected are representative of
Great Lakes basin wildlife which are
likely to experience significant exposure
to contaminants from aquatic food webs,
EPA requests comment on the selection
process and the results employed in the
derivation of wildlife criteriav
L Approach Used to Select
Representative Species IdBntifiedfor
Protection. To .select representative
avian and manamHlifln species, an
"analysis of wildlife species tiiat inhabit
the Great Lakes basin was undertaken to
identify those most likely to be exposed
to environmental contaminants from .
aquatic ecosystems (these representative
species are not necessarily the most
lexicologically sensitive species). This
analysis is presented in the Technical
Support Document for Wildlife Criteria.
With regard to mammalian species, -•:- :•
results of this assessment suggested that,
in general, piscivorous species are at
greatest risk from the'chemicals
identified for wildlife criteria
development (see section iii, belowj.
Two mammalian species were chosen to
represent the range of body weights and
food habits of piscivorous mammals, .-'.
Representative avian species Were
categorized based on three species-
specific parameters: body weight, food
habits (e.g., food source and prey size) '-.-.
and foragmig styles. Based on available .
data, the results of this assessment
suggested that with the precision of
available data, ingestion rates' for birds
were generally proportional to animal
mass and not influenced by foraging ' "
style. Therefore, EPA is proposing to
select representetive avian and "
mammalian species which represent a
range of body weights and food habiJs
appropriate for the Great Lakes basin
and which are likely to experience
significant exposure from the aquatic
food web, . .. •'. -.'..'.
EPArequests^ubmissionpfpeer" .-'
reviewed.enipMcal exposure
information for wildlife species residing
in the Great Lakes basin which were not
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
referenced In the analysis presented in
tho Technical Support Document for
Wildlife Criteria and which the
commcnter feels should be considered
in the selection of representative avion
and mammalian species.
As a result of applying this approach,
tho representative species proposed to
represent avian and mammalian species
of the Great Lakes basin which are likely
to experience significant exposure to
contaminants in aquatic ecosystems
through the food chain are the mink
(Mustela vison] and river otter (Lutra
canadensis) and the belted kingfisher
(Ceryle al^yon), osprey (Pandion
haUatus) and bald>eagle (HaUaeetus
Jeucocephalus), EPA specifically invites
comment on the choice of representative
spocics identified for protection, and
requests that the public document the
basis for considering other species.
The SAB, in their December 1992
report (U.S. EPA, 1992), recommended
that the approach to protect wildlife be
expanded to consider ecologically
representative species. EPA
acknowledges that the approach used to
select representative species does not
consider potential impacts on wildlife
species due to changes in communities
or the ecosystems in which they reside
and recognizas the need for research to
bettor understand the large uncertainties
which currently exist in this area. EPA
welcomes suggestions on how to select
ecologically representative species given
tho current state of knowledge.
ii. Bioaccumulation Factors. The
procedure for determining the
appropriate bioaccumulation factor
(BAF) for calculation of Tier I wildlife
criteria and Tier n wildlife values is
§ resented in appendix B to part 132.
ascd on the food habits of the
representative wildlife species, BAFs
calculated for trophic levels 3 or 4 may
be used, BAFs for invertebrates, aquatic
plants or other trophic levels may also
be used on a case-by-case basis based on
their proportion in the total diet
consumed bv the wildlife species
requiring greater protection.
Hi, Exposure Routes Considered. The
derivation of the equation used to
calculate wildlife values, which are in
turn used to calculate a wildlife
criterion, considers oral exposure (i.e.
food and water ingestion). EPA
considers oral ingestion the most
significant route of exposure for
bioaccumulative pollutants and these
pollutants represent the greatest risk to
wildlife species. EPA requests
comments on this assumption.
In its December 16,1992 report,
"Evaluation of the Guidance for the
Great Lakes Water Quality Initiative"
(U.S. EPA, 1992), EPA's SAB expressed
concern that the wildlife exposure
assessments hi the proposed guidance
do not consider exposures via
inhalation or dermal contact which may
be important for chemicals with
significant vapor pressure and
intermediate molecular weights. EPA
solicits modifications of the proposed
approach which would address these
concerns and consider other significant
routes of exposure for non-
bioaccumulative chemicals.
C. Additional Issues
The sections below highlight some of
the issues and discussions which
"occurred during the development of the
wildlife criteria methodology proposed.
EPA solicits comments on each of these
issues.
1. Use of Human Health Paradigm
The December, 1992, SAB report (U.S.
EPA, 1992) states that the wildlife
criteria concepts were formulated
around the perceived requirements of
the human health paradigm and they are
inadequate for wildlife. Adjustments
made to the human health paradigm
include: (1) Defining database
requirements such as preferred test
species, test length, and toxicological
endpoints; (2) selection of species
representative of wildlife species likely
to experience significant exposure from
aquatic food webs and for which
empirical dietary exposure information
was available; and (3) options for the
use of various uncertainty factors to
ensure protection of the distribution of
wildlife species. Given the extent of
current exposure and toxicological data
available for wildlife species, EPA
believes the methodology (presented in
appendix D to part 132, and clarified ii
the appendix to this preamble and the
criteria derived based on this
methodology, are scientifically
defensible. EPA requests comments on
additional modifications to the
proposed methodology which would
improve its scientific defensibility.
2. Minimum Data Bass for Wildlife
Criteria Derivation
There was a considerable amount of
discussion in the Committees of the
Initiative and at the Workshop on the
minimum toxicological database
requirements for both Tier I criteria and
Tier n values. Due to the uncertainties
hi extrapolating data across taxonomic
classes, EPA is proposing to require that
the minimum toxicity database for Tier
I criteria must provide enough data to •
generate a subchronic or chronic dose-
response curve for both birds and
mammals. For Tier n values, the
minimum toxicity database need only
in
provide enough data to generate a
subchronic or chronic dose-response
curve for one taxonomic class (Aves or
Mammalia). In all cases, any study used
in the derivation of wildlife criteria or
values should be peer-reviewed.
Additionally, if available, field
studies of wildlife species shall take
precedence over studies using
traditional laboratory species in the
development of wildlife criteria and
values because uncertainties in
extrapolating from laboratory to field
impacts are reduced. Any laboratory
studies used must use avian or
mammalian species.
The oral exposure routeJs the primary
route of exposure to be considered in
selecting toxicity studies. EPA proposes
that studies involving other exposure
routes (e.g., dermal or inhalation).
should be considered in the derivation
of a Tier I criteria or Tier H value only
when an equivalent oral dose can be
estimated. Such an estimation should be
supported by toxicokinetic and in vivo
metabolism data. Without this
supporting data, the mechanism of
toxicity and/or the dosimetry for these
routes of exposure cannot be assumed to
be the same as for the oral route of *
exposure, and the criteria and value
calculations are based on an oral route"
of exposure. .
If laboratory studies are used to derive
a Tier I criteria, EPA is proposing a 90-
day requirement for any mammalian
study and a 28-day requirement for any
aviaii study. This is to ensure that the
toxicity data on which a wildlife
criterion is based does not
underestimate effects associated with
repeated exposures to a chemical.
If laboratory studies are used to derive
a Tier n value, EPA is proposing the
same requirements for Tier I except a
28-day mammalian study which meets
the other requirements presented in
appendix to part 132 may also be used
3. Acceptable Endpoints for Toxicity
Studies - "'
The acceptable endpoints on which
the NOAEL determined from the
toxicity study must be based are defined
in the wildlife methodology presented
in appendix D to part 132. These
endpoints were selected because they
are parameters most likely to influence
population dynamics. When more than
one study is available which assessed
different endpoints, EPA recommends
that preference be given to studies
which assess endpoints which best
reflect potential impacts to wildlife
populations.
EPA's SAB, in their December 16,
1992 report (U.S. EPA, 1992),
recommended that EPA develop
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Federal Register / Vol. 58, No, 72 7 :Friciay," April 16, 1993 7 'Proposed Rules
20883,
. guidance for the selectipn of NOAELs
appropriate for the protection of wildlife
populations as -distinct from tlia
protection of individuals. EPA proposes
that the restrictions and clarifications
provided in the methodology adequately
address this concern given the current
extent of knowledge regarding •••
population dynamics. EPA requests
comments on other approaches which
may address the recommendation :
received from EPA's SAB. . . •-
4. Use of .an Acute to Chronic
Conversion Ratio
Participants at the Workshop and the
Committees of the Initiative discussed
the application of acute to chronic
conversion ratios in the derivation of
Tier I criteria. An acute/chronic ratio is
applied to acute toxicity data {typically
mortality) to estimate chronic effect :
levels. Workshop participants
; concluded that more data analysis of '
existing mammalian and aviari acute
and chronic toxicity data, possibly
broken do wa by class of compound or
mode of action, was needed to
adequately define the empirical
relationship between acute endpoints
(e.g., LD5Q, the lethal dosage causing
death in 50 percent of the exp osed
animals) and chronic endpoints (e.g.,
NOAEL, thehighesttested doisage
causing no observed adverse effect).
Workshop participants recognized that
before the use of acute/chronic ratios
could be scientifically defensible,
additional toxicity data might be
needed. Given the current limited
database, there was concern that the
factor for extrapolating from acute data
to chronic data would have to be so
large that it would result in criteria or •
values which could be overly
conservative. Therefore, EPA is-
proposing not to incorporate the use of ".
an acute-to-chronic conversion factorm
the Tier I methodology. EPA Is also \
proposing that Tier II values not be
based solely on acute toxicity data,
instead requiring the use of subchronic
or chronic data to derive an effect value.
EPA invites comments on these
proposed decisions.
D. Chemical Selection for Wildlife
Criteria Derivation -
The types of chemicals for which
wildlife criteria" should be developed
under the GLWQI were adt
Workshop, These are; those which
bioaccumulate {because wildlife species
occupy higher levels in the trophic
structure of a food web and, therefore,
have a higher exposure); and those
which have a unique metabolic pathway
or mode of action which may make
birds or mammals more'sensitive
lexicologically. The Committees of the ,
Initiative agreed with the proposals of
the Workshop that chemicals BAF
greater than 250 should receive top
priority for derivation of wildlife 1 . -...-,.
criteria. In addition, chemicals with
B AFs less than 250 where wildlife
impacts are suspected (e.g.; lead) were
included in the top priority list
The Initiative Committees also
identified nonpersistent, multiple
application biocides (such as triazine
herbicides and carbamates) .are another
group of chemicals for which wildlife ;
criteriamay be derived. These
chemicals, although they are highly
degradable and, therefore, have low
bioaccumulation factors, are known to
have detrimental effects on wildlife,
EPA agrees that the chemicals —
described above are those that most
warrant the development of wildlife •';-
criteria and values.'EPA is not requiring
the Great Lakes States or Tribes to
.develop values for all of these ,
chemicals, nor is EPA prohibiting any
State or Tribe from addressing rather
chemicals if it believes that those other
chemicals are causing adverse impacts
on wildlife. EPA merely recommends
that States or Tribes place a high
priority on .developing wildlife values
for the chemicals identified by the
Committees. EPA also intends to focus
any future efforts to develop additional
Tier I criteria for wildlife on these same
chemicals of concern. ,
E. Tier I Wildlife Criteria and Tier n
Wildlife Values
In the proposed Guidance, there are -
four chemicals for which Tier I wildlife
criteria are proposed. These are
mercury, PCBs, 2,3,7,8-TCDD, and DDT
and metabolites. Only four wildlife
criteria are being proposed for two
major reasons: field studies from the, -
Great Lakes indicate that the f our ,
pollutantsfor which wildlife criteria are
proposed have had the most severe
impacts on wildlife within the Great
Lakes; and the criteria proposed ere. the
first set of criteria for wildlife that EPA
has ever developed. EPA cannoftake
advantage of an established and peer-
reviewed National methodology to
develop National wildlife criteria as it
can lor both human health and aquatic
life criteria. The Initiative Committees
and EPA lacked time and resources to
develop additional numeric criteria for
wildlife prior to this proposal, The State
of Wisconsin had already identified
these four chemicals as chemicals of
concern for wildlife impacts in their
State and completed literature reviews
for these four chemicals. The'se ' ,
literature reviews were "updated, as part
of the GLWQi effort The proposed
numerical criteria are presented inr
Table ¥1-1. For additional information.
EPA refers readers to the proposed
methodology in appendix D to part 132,
the .Technical Support Document
located in the appendix to this , "
preamble, and the individual criteria
documents available in the
administrative record for this . ,
rulemaking. No Tier II wildlife values V
were calculated for inclusion in the
proposed Guidance,
Vi-1.—GREAT LAKES HER I
WILDIJFE CRITERIA
.Chemical
p.p'-dichloro- . diprjenyltnchloro-
ettiane (DDT) and Metabolites
Mercury / (including
Mefcylmsrcury) .........
Polychlorjnated " biphenyls
(PCEs) „,..„....„„„.„...;...... i
2,3,7,8-t@tracrilorodibenzo-p-
dk»dn <2,3,7,e-TCOD) „.
Criteria
0-87
180
..-'•17 :
;, 0.0098
F. Comparison WitiitheCWAand
Relationship to National Guidance
The observed effects on wildlife
species in the Great Lakes basin .are
clear evidence that the Clean Water Act
(CWA) goals of protecting the biological
integrity of the Nation's waters and
attaining water quality which provides
for;the protection of-wildlife are not
being met in the Great Lakes {see 33
U.S.c;;1251ferj.
1. Relationship to Existing National •
Guidance ;
Currently, there exists no National
.guidance for wildlife protection
comparable to the proposed Guidance.
However, there is a mechanism' for
consideration of wildlife impacts within
the 1985 National aquatic life criteria
guidelines (Stephen, et al,, 1985). 'In
those guidelines, if a maximum
permissible tissue concentration is
available from a.maximum acceptable
dietary intake based on observations on
survival, growth, or reproduction ii£ A
chronic wildlife feeding study; or.a
long-term wildlife field study, or from
an FDA Action Level, a Final Residue
Value can be calculated. This Final
Residue Value is calculated by dividing
maxiinum permissible tissue
concentrations by appropriate lipid-
nonnalized bioconcentration or ' •
bioaccumulation factors.'. '".-"•:
TMs methodology provides/a '
mechanism to protect against
bioaccumulation of a compound 'within
a food web. However, it also'has ,
' limitations, A Final Residue Value
derived using aa FDA Action Level does
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20884 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 '/ Proposed Rules
not ensure protection of wildlife species
which may consume contaminated
aquatic organisms as a larger portion of
thoir diet or exhibit a greater sensitivity
than the human which the FDA Action
Level is derived to protect. If no
maximum permissible tissue
concentration is available, no Final
Residuo Value is calculated and,
therefore, biomagnification of a
chemical into the higher trophic levels
of a food web, and potential impacts on
these wildlife species, is not considered
in the derivation of the Aquatic Life
Criterion.
EPA's current National aquatic life
criteria for DDT and PCBs are based on
wildlife toxidty information (U.S. EPA,
1980 a and c, respectively). Wildlife
toxiclty data was also considered in the
derivation of the current aquatic life
criterion for mercury (U.S. EPA, 1980b).
For both DDT and PCBs, a
bloconcentration factor (BCF) rather
than a bioaccumulation factor was used
In the derivation of these aquatic life
criteria. In both cases, the BCF was
known to underestimate the
bioaccumulative potential of the
compound, and in the PCB Aquatic Life
Criteria document (U.S. EPA, 1980c),
underestimating the bioaccumulative
potential was identified as leading to a
criterion which may be underprotective
of wildlife species at risk.
EPA has begun a separate effort to
derive National wildlife criteria.
Following the release of the 1987
General Accounting Office report
entitled "National Refuge
Contamination is Difficult to Confirm
and Clean Up," (GAO, 1987), EPA began
to work cooperatively with U.S. Fish
and Wildlife Service to develop
methods for deriving National wildlife
criteria. The wildlife criteria efforts
carried out within the Great Lakes Water
Quality Initiative have been coordinated
with the on-going National efforts.
However, within the development of
National wildlife criteria, wildlife are
defined as mammals, birds, reptiles and
amphibians. This broader definition of
wildlife was considered hi the early
stages of wildlife criteria development
for the GLWQJL However, the decision
was made to move forward with wildlife
criteria considerate of impacts on
mammals and birds at this time because
of the lack of chronic or sub-chronic
lexicological data for reptiles and
amphibians. The incorporation of effects
on reptiles and amphibians is also
complicated by the significance of, and
lack of data for, the dermal route of
exposure to reptiles and amphibians.
EPA requests recommendations on how
reptiles and amphibians can be
incorporated into the proposed GLWQI
methodology or suggestions for an
alternative wildlife criteria methodology
considerate of impacts on reptiles and
amphibians.
2. Relationship to Current Efforts To
Provide National Guidance for the
Development,of Wildlife Criteria
There are efforts underway within
EPA to develop guidance for National
wildlife criteria. The proposed
Guidance is being considered as one
alternative which might be modified for
nationwide use. The Great Lakes
Guidance has as its focus the protection
of wildlife populations inhabiting the
Great Lakes basin. Although National
guidance may eventually be modeled on
the proposed Guidance, it should not be
expected that the National guidance
would result in identical criteria. EPA
invites comments on the modification of
this approach for development of a
National wildlife criteria procedure.
G. Comparison of Wildlife Criteria and
Methods to National Program and to
Great Lakes Water Quality Agreement
1. "No Less Restrictive" Than the CWA
and National Guidance
Since the current National guidance
contains no method for calculating
criteria for the sole protection of
wildlife and no values based solely on
the protection of wildlife, a direct
comparison is difficult. The National
guidance allows some consideration of
wildlife impacts hi the calculation of
criteria for aquatic life. Current National
criteria for aquatic life can be compared
with the proposed criteria for wildlife,
although the comparison may not be
especially meaningful. All four of the
Tier I criteria for wildlife proposed are,
hi fact, more restrictive than the existing
aquatic life standards for the same '
pollutants. Since the new wildlife
criteria will apply in almost all Great
Lakes waters, they will in a rough sense
provide more protection than the
National guidance.
As explained in section B above, in
the discussion of aquatic life criteria,
Tier II values will almost always be
more restrictive than both new Great
Lakes Tier I criteria and existing
National criteria. Hence, EPA believes
that future Tier n wildlife values
generally will not be less restrictive than
the National program.
2. Conformance With the Great Lakes
Water Quality Agreement
As explained above in the discussion
of aquatic life criteria, EPA does not
believe that Congress intended to
require EPA to adopt criteria identical to
the specific numerical limits set out as
"Specific Objectives" in Annex 1 of the
Great Lakes Water Quality Agreement
(GLWQA). In addition, only five of these
"Objectives" focus on the protection of
wildlife. EPA notes that the proposed ,
wildlife criterion that can be most
•readily compared to a wildlife limit in
the GLWQA is more restrictive than the
GLWQA's limit. EPA is proposing a
wildlife criteria for DDT of 0.87 pg/L.
The GLWQA's Annex 1 limit for DDT is
3.0 pg/L.
Finally, as discussed above, EPA
intends to try to revise the GLWQA to
replace existing Annex 1 limits with the
new criteria proposed.
H. Bibliography
Great Lakes Water Quality Criteria
Initiative. Appendix A: Uncertainty Factors
in Great Lakes Water Quality Criteria
Initiative Technical Support Document for ,
Human Health Criteria and Values. NTIS
#PB93-15468. ERIC: 3940.
National Academy of Sciences. 1980.
Problems of Risk Estimation, pp. 25-65 in
Drinking Water and Health, Volume 3,
National Academy Press, 2101 Constitution
Avenue, NW, Washington, DC 20418.
Stephan, C.E., D. I. Mount, D. J. Hansen,
J.H. Gentile, G.A. Chapman, and W.A.
Brungs. 1985. Guidelines for deriving
numerical national Water Quality Criteria for
the Protection of Aquatic Organisms and
their uses. PB85227049. National Technical
Information Service. Springfield, VA.
, U.S, EPA. 1980a. Ambient Water Quality ,
Criteria for DDT. Office of Water Regulations •
and Standards, Criteria and Standards
Division. U.S. EPA, Washington, DC EPA
440/5-80-038.
U.S. EPA. 1980D. Ambient Water Quality
Criteria for Mercury. Office of Water
Regulations and Standards, Criteria and
Standards Division. U.S. EPA. Washington,
DC EPA 440/5-80-058.
U.S. EPA. 1980C. Ambient Water Quality
Criteria for Polychlorinated Biphenyls. Office
of Water Regulations and Standards, Criteria
and Standards Division. U.S. EPA.
Washington, DC EPA 440/5-80-068.
U.S. EPA. 1980d. Appendix C. Guidelines
and Methodology Used in the Preparation of
Health Effect Assessment Chapters of the
Consent Decree Water Criteria Documents.
pp. 79347-79357 in Water Quality Criteria
Documents; Availability. Federal Register.;
45:79318-79378. Friday, November 28,1980.
U.S. EPA. 1992. An SAB Report:
Evaluation of the Guidance for the Great
Lakes Water Quality Initiative. Science
Advisory Board, U.S. EPA, Washington, D.C.'"
EPA-SAB-EPEC/DWC-93-005.
: U.S. EPA. 1985. Section.V.C. Evaluation of
Health Effects and Determination of RMCLs
pp. 46944-46950 in National Primary
Drinking Water Regulations; Synthetic
Organic Chemicals; Inorganic Chemicals and
Microorganisms. 50 FR 46936-47022. '
Wednesday, November 13,1985.
U.S. General Accounting Office. 1987.
.Wildlife Management National Refuge
Contamination is Difficult to Confirm .and
Clean Up. Gaithersburg, MD. GAO/RCED- :
87-128.
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Federal Register 7-Vol. 58, No. 72 / Friday; April 16. 1993 /Proposed Rules 20885
Wisconsin Administrative Code, Chapter
MR 105,Surface Water Quality Criteria for .'
Toxic Substances. Register, February, 1989,
No. 398. ' .•:,' . ' - '. .!..•'V ;'' .
Technical Support Document for Chapter
NR105 of the Wisconsin Administrative
Code. May 1988. ". "
VII. Antidegradation
A. General Discussion/Bflckground •_
Today's Federal Register notice
proposes guidance to be followed by tie
Great Lakes' States and Tribes in the
deyelopment of antidegradation policies
and implementation procedures for the
waters of each State that are within the
Great Lakes System. Antidegradation
policies and implementation procedures
are mechanisms that can be used by
EPA and the States to protect the water
quality of the Nation's surface waters
and to maintain improvements that have
been made in that quality.
", • The Federal regulations at 40, CFR
131.12 set out the Federal
antidegradation policy and require that-
each State develop and adopt a policy .
and methods for implementing that
:policy that, as a minimum, ar.e
consistent with the requirements set .
forth in the Federal policy. Furthermore,
the regulations at 40 CFR 131.6 require
each State to include such an
antidegradation policy as one of the
elements of the State's water quality
standards submitted.
Each Great Lakes State has adopted an
antidegradation policy'that EPA has
determined satisfies the minimum
requirements of the above Federal
regulations. However, the policies and
implementation procedures adopted by
the States vary considerably in form and
specificity, and EPA and the Great Lakes
States share concern that there exists
great potential for inconsistent .
antidegradation decisions to arise as a
result of these differences. JEP A and the
Great Lakes States agreed at the outset
• of the Initiative that one of the outputs !
of the process should be antidegradation
policy and implementation procedure
guidance; Each Great Lakes State would
follow^ the resulting guidance when
revising its water quality standards,
with the intended result being greater
consistency among State policies and
procedures. The passage of the Great
Lakes Critical Programs Act of 1990
' (CPA) made the development of this
Great Lakes antidegradation.guidance
mandatory. . . \ "
In September 1,991,'the States of
Michigan, Minnesota, and Wisconsin,
the Province of Ontario, the Government
of Canada, and EPA entered into an
agreement entitled "A Bi-National
Program to Restore and Protect the Lake
Superior Basin." Among the elements in
this agreement are enhanced
antidegradation requirements for areas -
of the Lake Superior Basin given special
protection designation by the three
States. This proposed Guidance
includes special antidegradation -..-."
requirements applicable to those areas
of the Lake, upon designation by a State
or States.
The following discussion briefly .
summarizes the history of the Federal
policy and outlines both the Federal
policy and that developed for the
proposed Guidance. It also provides a
detailed overview of the requirements of
.the antidegradation policy contained in
the proposed Guidance, which includes
an antidegradation standard,
antidegradation implementation
procedures, antidegradation
demonstration requirements, and ,
antidegradation decision requirements.
Unique characteristics and requirements
of the Great Lakes System and their
effect on the proposed Guidance,.as well
as specific issues that arose during
consideration of the options for the
proposed Guidance and their resolution,
are discussed. Finally, throughout the
discussion, EPA has identified specific
issues for which it is seeking comment
to aid in the development of the final
Guidance. - , '•
1. Federal Antidegradation Policy and
History . ,.: . -
&. History of the Federal .
Antidegradation Policy. The Federal
antidegradation policy haslts roots in
the Water Quality Act of 1965 (Pub. L.
89-234), which stated in its declaration
of policy, "The purpose of this Act is to
enhance .the quality and value of our
. .wafer'resources and to establish
national policy for the prevention, - "
control, and abatement of water
pollution."
Policy guidelines established by the
Department of the Interior in 1966 for
use in the approval of States'water
quality standards contained additional
. direction on antidegradation, stating
that "In no case will standards
providing for less than existing quality
be acceptable" and "The water quality
standards proposed by a state should
provide for: * * * The maintenance and
protection of quality and use or uses of
waters now of a high quality or of a
quality suitable for present and
potential future Uses." .Secretary of the
Interior Udall further defined the •
Federal policy on antidegradation in
1968, when he said that each State was .
to include a statement similar to the
' following in their water quality
standards: <
Waters whose existing quality is better
than the established standards as of the date
on which such standards become effective •
will be maintained at their existing high
quality. These and other waters of a State
will not be lowered in water quality unless
and until it has been affirmatively-
demonstrated to the; State water pollution
control agency and the Department of the
Interior mat such change is justifiable as a
result of necessary economic or social.,
development and will not interfere with or -
become injurious to any assigned uses made
of, or presently possible in, such waters. This
will require that any industrial, public or
private project or development which would
constitute a new source of pollution or an
increasecl source of pollution to high quality
waters will be required, as part of the initial
project design, to provide the highest and
best degree of waste treatment available
under existing technology, and, since these
are also Federal standards, these waste ,
treatment requirements will be developed ,
cooperatively. /.:-'
"•-' The Federal Water Pollution Control
Act Amendments of 1972 (Pub. L. 92-
500) continued to emphasize the , :
prevention of pollution and, in 1973,
EPA developed guidance for State water
quality standards under the
Amendments that-essentially repeated
the 1968 statements of Secretary Udall.
" In 1975, EPA promulgated regulations
at 40, CFR 13p.l7(e) that required the
States to develop an antidegradation
policy and implementation procedures.
The 1975 rule contained provisions that
are very similar to those in 40 CFR
131.12, and provided protections for
existing uses, high quality waters, high
quality waters that constituted an
outstanding National resource, and
waters impaired by thermal discharges.
To summarize, the 1975 rule/required
;that: ' ; •'.-/ ; ,."•'•;
i. Existing in-stream water uses must
be, maintained and protected and that no
degradation that would interfere with or
become injurious to existing in-stream
uses could be allowed; ' •
ii. High quality waters (those in which
the water quality exceeds that necessary
to support propagation of fish, shellfish
and wildlife and recreation in and on
the water) must be maintained and
protected unless the state chooses, after
public participation and
intergovernmental coordination, "to .-• •
allow lower wafer quality as a result of
necessary and justifiable economic or *
social development," and provided that
the degradation does hot interfere with
or become injurious to existing uses and
that the highest statutory and regulatory
requirements for .point sources and
feasible management practices, for.:
'nonpoint sources are achieved;
. in. High quality waters that constitute
an outstanding National resource must
' not be degraded; and; •.v •
iv. Where the potential for water
.quality impairment involved a thermal
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20886
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
discharge, anlidegradatlon policy and
Implementation must be consistent with
section 316 of the dean Water Act.
Citing the longstanding debate over
the impact of the antidogradation policy
on economic growth, EPA proposed to
change and significantly restrict the
effect of th« policy in 1982. In proposed
water quality standards rules published
in the Federal Register on October 29,
1982 (47 FR 49234), EPA proposed a
new antidegradation policy and took
comment on two alternative approaches.
Tho proposal would have created a new
40 CFR 131.10(c) which stated, "States
must develop and adopt a statewide .
antidegradation policy to maintain
existing water uses." As stated in the
preamble (47 FR 49238-49239), the
proposed regulation was "based on
limiting the mandatory antidegradation
policy to the protection and
maintenance of existing uses." The
preamble further stated that "the
emphasis in this proposal is on the use,
not the individual water quality
parameters which might, in any
particular water body, be higher than
necessary to protect the existing use."
The proposaleliminated special
protections for high quality waters and
Outstanding National Resource Waters,
but required that existing uses be
maintained regardless of future growth
or development that might affect water
quality,
One option, put out for comment in
the 1982 proposal, retained the existing
(1975) antidegradation policy, except
that it eliminated the provisions related
to outstanding National resource waters
because the Clean Water Act did not
Bnvide for such special designations of
Dtional resource waters. EPA did note,
however, that the States were free under
section 510 of the Clean Water Act to
make such designations in their water
quality standards.
Another option for public comment in
the 1982 proposal would have let the
States remove existing uses if their
protection and maintenance would have
effectively prevented future growth, or if
the benefits of maintaining an existing
use were outweighed by its costs.
Removal of an existing use would have
required full public participation and
would not have relieved any of the
Clean Water Act minimum technology
requirements for point sources.
The extensive public comment on the
1882 proposal favored retaining the
existing (1975) antidegradation policy
over any of the alternatives. In response,
EPA issued final rules on November 8,
1983 (48 FR 51400) that retained, with
certain changes, the 1975
antidegradation policy and incorporated
it into the regulations at 40 CFR 131.12.
The changes to the 1975 antidegradation
policy are discussed in the preamble to
the 1983 rulemaking (48 FR 51402-
51403), but they were generally
intended to clarify the policy with no
change in coverage or effect An
exception to this was the change in the
provisions applicable to outstanding
National resource waters, which
eliminated the strict "no degradation"
requirement in favor of a limited
exception for activities that result in
temporary and short-term lowering of
water quality. The resulting National
antidegradation policy is discussed in
detail below-under the heading Existing
National Antidegradation Policy.
Finally, the 1987 Water Quality Act
Amendments to the Clean Water Act
(CWA) explicitly incorporated reference
to antidegradation policies in section
303(d)(4)(B), which requires that such
antidegradation requirements be
satisfied prior to modifying certain
NPDES permits to include less stringent
effluentlimitations.
In addition, the Governments of
Canada and the United States have
entered into the Great Lakes Water
Quality Agreement of 1978 (GLWQA),
which also requires a strong
antidegradation process for its
objectives to be fully realized. The
purpose of the GLWQA is to restore and
maintain the chemical, physical and
biological integrity of the waters of the
Great Lakes Basin Ecosystem. In order to
achieve this purpose, the two
Governments have agreed to eliminate
and reduce to the maximum extent
practicable the discharge of pollutants
into the Great Lakes System. Both
Governments have established policy
under the GLWQA that the discharge of
toxic substances in toxic amounts be
prohibited and that the discharge of any
or all persistent toxic substances be
virtually eliminated. Finally, a Specific
Objective of the GLWQA is for all
reasonable and practicable measures to
be taken to maintain and improve the
existing water quality in those areas
where such water quality is better than
that prescribed by Specific Objectives
and in those areas having outstanding
natural resource value.
On November 16,1990, Congress
amended section 118 of the Clean Water
Act with the CPA. The CPA requires
that EPA develop a proposed and final
Guidance, including antidegradation
policies, and publish it in the Federal
Register. The Guidance must conform •
with the objectives and provisions of the
GLWQA and be no less restrictive than
the provisions of the Clean Water Act
and National guidance. States are
required to adopt into rules water
quality standards, antidegradation
policies, and implementation.
procedures which are consistent with
the proposed Guidance. If a Great Lakes
State fails to adopt such standards,
policies and procedures, EPA is
required to promulgate the Guidance for
that State.
b. Existing National Antidegradation
Policy. EPA has defined a "tiered"
antidegradation approach for the
protection and maintenance of water
quality based on the existing quality of
the water. The Federal antidegradation
policy at 40 CFR 131.12 establishes
three tiers of restrictions on the
lowering of water quality, and a fourth
requirement applicable to thermal
discharges.
The first tier, applicable to all waters,
is established by 40 CFR 131.12(a)(l),
which requires that all existing uses of
the water body and the level of water
quality necessary to protect those uses
be maintained and protected. EPA
interprets this to mean that water
quality in any water body may be
lowered only to the point at which the
Water quality is sufficient to protect and
maintain all existing uses, and that it is
not permissible to allow water quality to
be lowered to the extent that any
existing use is impaired. The 1983
Water Quality Standards Regulation
preamble described this provision as tha
"absolute floor of water quality in all
waters of the United States" (48 FR
51400,51403, November 8,1983). Note
also that other parts of the water quality
standards regulation provide that States
must adopt water quality criteria
sufficient to protect all designated uses,
and that designated uses must include
existing uses. Certain decisions
regarding the lowering of water quality,
such as those involving NPDES
permitted discharges, must also ensure
that the criteria applicable to such
designated mses are achieved, whether
or not the designated use is an existing
use.
The second tier is established by 40
CFR 131.12(a)(2), which provides
protection of actual water quality in
water bodies that support the
propagation of fish, shellfish, wildlife
and recreation in and on the water.
("fishable/swimmable"). Waters, the
quality of which exceeds that necessary
for fishable/swimmable, are termed high
quality waters (HQWs). Under 40 CFR
131.12(a)(2)r limited degradation of such
waters may be allowable if necessary for
important social and economic
development hi the areas in which the
waters are located, but only after public
involvement and only as long as the
water quality remains adequate to be
"fishable/swimmable." The process for
determining whether the lowering of
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water quality is necessary to -
accommodate important social and
economic development is referred to as
the antidegradation demonstration and
decision."
The third tier (40 CFR 131.12(a)(3))
affords special protection to waters that
have been designated Outstanding
National Resource Waters (ONRWs) by
the States. The water/quality in ONRWs
must be maintained and protected. The
preamble discussion in the 1983 Water
Quality Standards Regulation cited
above indicates that EPA did not intend
for this to be an absolute prohibition on
any lowering of water quality in
ONRWs. It allows States some limited
activities which result in temporary and
shott-term changes in water quality.
The final provision (40 CFR ;
131.12(a)(4)) requires that the State
antid,egradation policy and
implementation procedures be
consistent with section 316 of the;Clean
Water Act as regards lowering of water
quality involving thermal discharges..
This recognizes that thermal variances
granted under section 316 can override.
otherwise applicable water quality
standards, including antidegradation
standards. •
EPA has developed a variety of
guidance materials to'assist the States in
.the development of their
antidegradation policies and
implementation procedures, and to aid
EPA in the preview of such,pplicies and
procedures (e.g., Water Quality ,
Standards Handbook (1983)), which is
available in the administrative record
for this rulemaking.
c. Great Lakes States Experience. The
Great Lakes antidegradation policy
contains several requirements! that draw
. from the collective experience of the
Great Lakes States and EPA in studying,
managing and protecting the Great
Lakes System. The unique character of
the Great Lakes System and the
problems it faces are a major impetus
behind the Initiative in general, and the
basis for several of the specific
requirements in the Great Lakes
antidegradation policy.
Because of the long retention time and
the complex flow patterns of the water
in the Great Lakes System, the Lakes
tend to act as a sink, accumulating
pollutants discharged to them.-There is
an identified problem in the Great Lakes
associated with substances that are
highly bioaccumulative in the tissues of
aquatic organisms. Contamination by
such substances has resulted in State-
imposed fish consumption advisories •
and restrictions for humans, and has
• been implicated in a variety of adverse
biological effects, such as impaired
reproductive success and deformities,
among aquatic organisms and the
wildlife that, consume them. A special ;
emphasis is made in the proposed
Guidance to restrict increases in the rate
of loading of highly bioaccumulative
chemicals. Such "bioaccumulative
chemicals of concern" (BGCs) are those ,
with a bioaccumulation factor of 1000 or
greater, determined using the GLWQI
BAF procedures. The BAF procedures
are found in appendix B and the list of.
BCCs are found in Table 6 of section
132.4 of the proposed Guidance. BCCs
are discussed in detail and comments
are invited in section LA of the ••--.'
preamble.
As discussed in detail below, under
C.2 "Significant Lowering of Water'
:Quality", the Tier n protections in the .
proposed Guidance for high quality
waters are focussed on actions that have
the potential to significantly lower
water quality, •
The unique character and importance
of the Lake Superior Basin is also
reflected in the proposed Guidance.
Provisions are included for special ,- >
protection of waters designated Lake
Superior—Outstanding International
Resource Waters or Lake Superior
Basin—Outstanding National Resource
Waters by the States. These are
discussed below under Special,
Antidegradation Provisions for Lake
Superior. .
The Great Lakes priorities should not
be interpreted as EPA's priorities for
water bodies nationwide. EPA expects
the significant lowering of water quality
to be potentially different in other areas
depending on the priority concerns
identified through water quality '
management planning processes.
d. Alternative Approaches to
Assessing Lowering of Water Quality.
The Federal antidegradation policy, and
the proposed Great Lakes
antidegradation policy, apply to actions
that lower water quality. Typically,
water quality is considered to be
lowered when the concentration of a
pollutant in the water is increased, or.--
the concentration of a necessary •. ' •
substance such as dissolved oxygen is
decreased. In developing the proposed
guidance EPA and the Great Lakes
States considered several alternative
approaches that could be used to assess
whether an action would potentially
lower water quality.
One approach'that could be used to
.determine if water quality was. lowered
would rely on sampling and analysis of
'the water body to determine if any
measurable change occurred in the
concentration of a pollutant or
pollutants. EPA and the Great Lakes
States considered such an approach
during the development of the proposed
Guidance. This approach has the
advantage that it actually .uses
information about the ambient levels pf
pollutants to determine if a change in
water quality occurs. The approach is;
not proposed in the proposed Guidance,
however, because many of the
pollutants about which the Great Lakes
States and EPA are most concerned,
cause'adverse effects in the Lakes at
concentrations 'that cannot be measured
in the ambient water using readily
available analytical techniques. .
Furthermore* EPA and the Great Lakes
States are concerned about the potential
difficulty a regulatory agency would
face in linking the actions of a specific
source of the pollutant to the measured
change in ambient water quality. Finally
EPA is very concerned that such an
approach is contrary to the intent and
plain text of the Federal antidegradation
regulation. In particular, 40 CFR -.
131.12(a)(2) requires that water quality
be maintained and protected unless a
State finds that the lowering of water
quality is necessary to accommodate
important social and economic
development. This clearly necessitates
an affirmative finding by the State
before a water quality can be lowered,
not after it has been measured.
: Another approach that could be used
to determine whether an action could
lower water quality would look at the
amount of pollutant released into the • ;
water. Working from the premise that,
"all other things being equal, a change in
the amount of a pollutant added to a
water body will result in a change in the
concentration of that pollutant in the ,
water body, such an approach would .
look at changes in the mass loading rate
of a pollutant or pollutants as being
potential indicators of changes in water
quality. EPA and the Great Lakes States,
considered several alternatives that
would implement such an approach. All
of the alternatives that derive from-this ;
approach would require prior approval
of a change in the loading of a pollutant
if that change lowered water quality or
was projected to lower water quality.
Where the alternatives differ is in the
threshold at which water quality is
determined to be lowered and the
flexibility provided the regulatory
agency in making such a determination.
One alternative EPA and the Great
Lakes States considered would define
the lowering of water quality in terms of
a projected increase in the ambient
concentration of a pollutant. This
'alternative would use models (simple
mass balance or more sophisticated
dynamic models if appropriate) to •
project the effect of a change in the mass
loading rate of a pollutant or pollutants
on water quality, generally focussing on
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
changes in effluent limitations and
wasteload allocations. This is the way in
which antidegradation policy has
typically been implemented in the past.
A second alternative EPA and the
Groat Lakes States considered would
define any increase in the rate of mass
loading of a pollutant as lowering water
quality. This alternative was appealing
to EPA and the Great Lakes States
because the Great Lakes tend to act as
a sink for many pollutants and there
was a concern that the models used in
tha first alternative would not be
protective for persistent pollutants that
might accumulate in the Lakes.
A third alternative considered for the
proposed Guidance is a hybrid of the
first two. To account for the concerns
with the BCCs, the proposed Guidance
would consider the lowering of water
quality to occur whenever the rate of
mass loading of these pollutants (BCCs)
from an individual point or nonpoint
sourca increases. For the remaining
pollutants (tha non-BCCs), any increase
in an existing limitation beyond a de
minlmls change would be considered an
action that would lower water quality
sufficiently to require an
antidegradation review. This approach
would focus regulatory attention on the
pollutants of primary concern—the
BCCs—and, for the remaining (non-
BCC) pollutants, use information on the
effect of the proposed action on ambient
water quality in determining the need
for an antidegradation determination.
EPA and the Great Lakes States settled
oa such a hybrid alternative and it is
embodied in the definition of significant
lowering of water qualify in the
proposed Guidance.
The sections that follow set out in
detail the basic elements of the
proposed approach and discuss some
alternatives for each of those elements.
EPA requests comments on all of the
alternative approaches identified above.
In providing comments, EPA is
particularly interested in Information on
tha relative effectiveness of these
alternative approaches in meeting water
quality goals, the difficulties and
advantages of their implementation, and
their likely costs. EPA is also interested
in comments on the effect of requiring
prior approval, through the
antidegradation process proposed in
this Guidance, of actions such as
di«charga increases that have the
potential to lower waterquality. EPA
recognizes that delays in business
decisions, such as prdduction rate
increases in response to market changes,
might result because the attendant
pollutant loading rate increases would
require prior approval. As a result of the
requirement for loading limits in the
implementation procedures proposed
today, and the focus on loading rates of .
the BCC pollutants, EPA believes that a
larger number of .actions may be subject
to antidegradation review and prior
approval requirements than under
existing policy. The potential costs that
might be associated with decreased
flexibility to respond to market changes
could, therefore, also be greater than
under existing policy, EPA has no data
from which to estimate the potential
costs that might be associated with
decreased flexibility to respond to
market changes; However, EPA is
interested in any such information that
commenters are able to provide.
The definition of significant lower of
water quality reflects the unique
characteristics of the Great Lakes
System (as described below). Actions or
decisions that have the potential to
significantly lower water quality
include those that might result in any
increase in the actual rate of mass
loading of a BCC and those that require
an increase in an existing limitation for
any other pollutant. EPA is also
interested in comments though, on
whether the definition of significant
lowering of water quality should
distinguish between BCCs and other
chemicals. In particular, EPA is
interested in whether BCCs wouldie
adequately controlled if the same
definition of significant lowering of
water quality as is applied to other
chemicals were to be used for BCCs.
Such an approach would have the effect
of tying the definition of significant
lowering of water quality for all
pollutants to increases in permit limits.
It would provide opportunity for a de
minimis demonstration for increases in
limitations on BCCs. It would also
provide opportunity for an entity to
attempt to demonstrate that the ambient
concentration of the BCC would not
increase. EPA also welcomes *
suggestions regarding any changes or
specific requirements that should be
made or added to the de minimis test
and the demonstration of no ambient
change to address BCCs if the definition
of significant lowering of water quality
were to be changed as discussed above.
EPA invites comment on these
approaches and suggestions for others
that should be considered.
B. General Outline ofGLWQL
Antidegradation Process
1. Narrative Flow Chart of Process
As previously noted, the CPA
mandates that the EPA publish, among
other things, an antidegradation policy.
The Great Lakes antidegradation policy
proposed in the proposed Guidance is
comprised of the following four
components: antidegradation standard,
antidegradation implementation
procedures, antidegradation
demonstration, and antidegradation
decision. The policy is constructed as a
model regulation in the following
sequence.
the "Antidegradation Standard" is a
statement of the general requirements
with regard to maintenance and
protection of water quality in the Great
Lakes System. It is generally the same as
the National regulation. Additionally, it
clarifies that the lowering of water
quality is to be considered and
evaluated on a pollutant-specific basis.
The "Antidegradation
Implementation Procedures" define the
procedures to be used by the Great
Lakes States and Tribes to implement
the general Standard. Appendix E,
sections II.B through D, establish tiered
procedures, specific to the quality of the
water in question, which track the tiered
approach of the Standard. The
procedures identify priorities of the
Great Lakes States and Tribes with
regard to BCCs and define situations in
which the lowering of water quality in
HQWs will be considered significant
and subject to a detailed antidegradation
demonstration review pursuant to this
proposed Guidance. Appendix E,
section H.D, specifically addresses
maintenance of water quality in HQWs
with respect to bioaccumulative
chemicals of concern and other
pollutants. This section also identifies
special designations available for Lake
Superior and defines the procedures
and restrictions applicable to areas of
the Lake so designated.
The "Antidegradation
Demonstration" defines the information
'that an entity that is seeking to
significantly lower water quality in a
high quality water must provide in
support of that request. It promotes
pollution prevention and requires that
entities develop information regarding
the costs associated with the use of
alternative or enhanced treatment that
would eliminate the lowering of water
quality. This section also identifies
information that must be provided by
any entity proposing a new or increased
discharge of any Lake Superior
bioaccumulative substance of
immediate concern (BSIC) to a Lake
Superior Outstanding International
Resource Water.
The "Antidegradation Decision"
identifies the process that the State->r
Tribe will follow in evaluating the
information provided in the
antidegradation demonstration and in
reaching a decision on the significant
lowering of water quality. The proposed
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20889
Guidance directs the State or Tribe to
require the entity to implement prudent
and feasible pollution prevention
alternatives that reduce the e)ctent of, or
eliminate, the lowering of water quality.
It also identifies minimum expenditures
for alternative or enhanced treatment
that will be required of an entity if the
treatment eliminates the lowering of
water quality. It further requires' that the
State or Tribe consider the social and
economic benefits in light of the ,
environmental effects associated with
the lowering of water quality in order to
reach the decision. The State or Tribe
may either conduct a full review of the'
technical merit of the demonstration
and make its tentative decision
accordingly, or alternatively, the State
or Tribe may choose, to determine that
the administrative requirements of
- section YD. B.l.c of the preamble, have
been met and solicit public comment
prior to such a technical review. In the
latter instance, the tentative decision of
the State or Tribe shall be, as a matter
of policy, to propose that existing water
quality be maintained and protected.
The Antidegradation Implementation
Procedures place requirements on the
, decision-making of the Federal, State ;
" and local regulatory agencies as they
consider actions proposed by a
regulated entity, whether involving a
point or nonpoint source, thai: have the
. potential to lower water quality beyond
. a specific threshold. (Note that
throughout the Policy, the term
"Director" is used to signify the
.decision-maker in the regulatory
agency.) For all tier 1 waters where
. water quality for a particular pollutant
or pollutants'does not exceed that
^required to maintain the designated uses -
and the existing uses, the threshold is
any lowering of water quality,, as '
signified by any increase in the rate of
mass loading of the pollutant or
, pollutants to the water. In such waters,
no increase in the rate of mass loading
of any such pollutant is allowable, so
the procedures direct the regulatory
agencies to write control requirements,
such as NPDES permit limitations, that
at a minimum,will prevent increases in
the rate of mass loading of the pollutant
or pollutants of concern. For
outstanding National resource waters ^
(tier 3), the threshold is any lowering of
• water quality for any pollutant In such
waters, no' increase in the rate of mast
loading of any pollutant is allowable,'so
the procedures direct the regulatory
agencies to write control requirements,
such as NPDES .permit limitations, that
• at a minimum will prevent increases in
: the rate of mass loadmg'of all
pollutants, FoiHQWs (tier 2), the
threshold is any significant lowering of
water quality, a term which is defined
in the proposed Guidance and discussed
later in this preamble. For Lake Superior
Basin waters provided special
protection designation by a State or •-',
States, the proposed .Guidance describes
specific restrictions on the lowering of
water quality by any of nine listed Lake
Superior bioaccumulative substances of
immediate concern (BSICs). (The Bi-
National Program to Restore and Protect
the Lake Superior Basin identifies two
special protection designations that
might be adopted by the States. The first
such designation, a Lake Superior
Basin—Outstanding National Resource
Water, is ah area within the basin so
designated by a State for the purpose of
preventing new or increased discharges
of BSICs from point sources. The
second, Outstanding International
Resource Water, exists if the States
(Michigan, Minnesota and Wisconsin)
so designate the Lake Superior Basin,
and has the effect of preventing the new
or increased discharge of BSICs until an
adequate antidegradation
demonstration,, which includes the
installation of the best technology- in
process and treatment, is
accomplished.) For substances other
than the BSICs, the Lake Superior.
special protection designations have no
direct effect, and such substances are
treated the same as in the remainder of
the Great Lakes System.
Proposed actions that have the
potential to significantly lower water
quality in HQWs must be evaluated by
the regulatory agency to determine if
they are necessary to accommodate .
important economic and social •
development in the;area in which the
waters are located. To guide the
regulatory agency in making this
determination, the proposed Guidance
establishes two tests: one that
demonstrates that the significant •
lowering of water quality is necessary,
i.e., the lowering of water quality cannot
be prevented through the use of prudent
and feasible pollution prevention
techniques, or alternative or enhanced "'
treatment techniques that are available
within a specified cost range; and a
second, subsequent test that is used to
establish that tiie action significantly
lowering water quality will
accommodate important economic and
social development in the area in which
the'waters are located,, . . •'.:',.
•The proposed Guidance identifies five
categories of pollution prevention
alternatives that must be evaluated:
substitution of BCCs with other •.;'.-..
nonbioaccumulative and nontoxic
chemicals; application of .water' -••.-.
conservation methods; waste source ' ;
reductions within process streams;
.recycle arid reuse of waste byproducts;
and manufacturing process, operational
changes. In addition, the Director may
add categories of pollution prevention
alternatives which are applicable to
specific situations. For instance, the
alternative of scaling down the amount
of fill might be appropriate in a section
404 permit action. The proposed
Guidance requires that the entity
proposing the action supply to the
regulatory agency information on the
alternatives available, their
effectiveness, and costs, along with any
other information the agency might • •
require to determine if ^specific
alternatives alone or in combination are
prudent and feasible. The Director will
require the entity to implement
alternatives that are determined to be
prudent and feasible and will establish
" control requirements that reflect the
implementation of such alternatives.
The implementation of prudent and
feasible pollution prevention
alternatives need not entirely eliminate
the significant lowering of water, quality
for them tabe required by the Director.
Unlike the alternative or enhanced
treatment provision discussed below,
prudent and feasible pollution
prevention alternatives are to be
"required whenever they are effective at
reducing the degree to which water
quality would be significantly lowered"
by an action., ." V
The proposed Guidance also
identifies benchmarks to be applied by
the regulatory agency in determining if
alternative or enhanced treatment
techniques should be required, in . ,
addition to prudent and feasible
pollution prevention .alternatives, to
eliminate the lowering of water quality:
that would otherwise result from an
action. The proposed Guidance directs
the entity proposingthe action to ~
identify for review by the,regulatory
agency any alternative or enhanced
•treatment techniques available that
would, in conjunction with the , '•-
implementation of prudent and feasible
pollution prevention alternatives,
/eliminate the need to significantly lower
water quality, along with, the associated
capital and operation and maintenance
costs. In addition, the, entity must
provide comparable information on the
capital and operation and maintenance
costs associated with pollution control
facilities necessary to achieve -
compliance; with applicable Federal '
effluent guidelines-based or water
quality-based effluent limitations. The
proposed Guidance directs the
regulatory agency to require the '•
implementation; of such alternative or •
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enhanced treatment techniques that are
available at a cost ratio of l.l to one
(alternative or enhanced treatment
compared to that otherwise required).
If, after the above evaluations and
implementation of the prudent and
feasible pollution prevention alternative
or alternatives, the proposed action will
continue to significantly lower water
quality, then the action must he
evaluated by the regulatory agency to
establish that the significant lowering of
water quality will accommodate
important economic or social
development in the area in which the
waters aro located. The proposed
Guidance requires that the entity
proposing the action identify
developments, falling in any of the
following categories, that will be
foregone if the significant lowering of
water quality is not allowed; increase in
the number of jobs; increase In personal
income or wages; reduction in the
unemployment rate or other social
service expenses; increase in tax
revenues; or provision of necessary
social services. No benchmarks are
specified for the evaluation of the social
and economic developments; rather the
regulatory agency is provided the
flexibility to fit the analysis to the
condition of the community and area
involved. Nonetheless, the action
should have some positive
developmental effect in one or more of
the categories listed above or the
lowering of water quality should not be
approved by the regulatory agency.
Furthermore, the proposed Guidance
provides for a review by the Director of
information on the environmental
effects of the action, after required
pollution prevention/control
alternatives are implemented. Such
environmental effects would not be
limited to the water media; the
information could be used by the
regulatory agency to account for cross-
media effects in making the final
decision,
The proposed Guidance provides two
options to the regulatory agency on the
draft decision regarding the lowering of
water quality, which vary depending on
how the agency decides to complete the
roviaw of the social and economic
developments. The agency may wish to
conduct a full review of the merit of the
action and make its tentative decision
accordingly, in which case it would
public notice the resulting proposed
decision and the basis for the decision.
Alternatively, the agency may wish to
take public comment on the action and
associated social and economic
developments before it renders a
decision based on its review of the
merits of the antidegradation
demonstration. In this case, the agency
would public notice a tentative decision
to maintain and protect water quality
(i.e., reject the significant lowering of
water quality). The public notice would
include for public review and comment
the antidegradation demonstration
•provided by the entity proposing the
action, along with the agency's
determination that the demonstration is
administratively complete. The notice
would furthermore indicate that the
agency had deferred its decision on
allowing a lowering of water quality
pending review of the public comment,
and that the tentative decision to
maintain and protect water quality may
be revised based on public comment
and the agency's review of the full
antidegradation demonstration.
2, Preconditions for Implementation of
Antidegradation Procedures
Several other ongoing water quality
management planning processes are
integral to antidegradation
implementation, and for the purpose of '
this procedure are expected to be
implemented correctly as preconditions
to antidegradation review of any
proposed action that could significantly
lower ambient water quality.
Deficiencies in these underlying
programs should be corrected before any
activity is considered .that could
significantly lower water quality. .
At the onset of the antidegradation
review procedure, the water quality
standards established for the receiving
water body pursuant to 40 CFR131
must be correct and appropriate. The
term "water quality standards" as used
here is defined at 40 CFR 131.3(i) and
includes both the designated uses of the
water body and the criteria that support
the designated uses. Existing uses and,
where attainable, fishable/swimmable
uses are expected to be reflected in the
.use designation, and appropriate criteria
to support those uses adopted. It is
assumed that if the standards have
undergone the triennial review process.
in the last three years and are approved
by EPA, they are correct and
appropriate.
The potential for an action to result in
a significant lowering of water quality
will be considered on a parameter-by-
parameter basis. Unless the appropriate
and established water quality standards
have been achieved, there is no
potential to allow an action that could
lower water quality, subject to an
antidegradation review, because there
would be no remaining unused
assimilative capacity. Water quality
standard exceedances may be a result of
any one or a combination of factors,
including but not limited to: an
inadequate total maximum daily load
(TMDL), wasteload allocation (WLA), or
load allocation (LA); uncontrolled
sources; and point source dischargers
that are not in compliance with their
NPDES. permits, Such water quality
standards violations must be corrected
prior to consideration of an increased
loading of a pollutant from any source
through the antidegradation review
process. Further, if water quality
standards are not being achieved, the •;
State should establish a revised TMDL/
WLA/LA; bring non-compliant
dischargers into compliance with
appropriate water quality-based effluent
limitations; or, in some other way,
correct the ambient water quality
problem.
3. Steps Preceding an Antidegradation .
Review
a. Establish That the Action May
Significantly Lower Water Quality. Prior
to requiring an antidegradation
demonstration and review the
regulatory agency must establish that
the proposed action results in, or may
result in, a significant lowering of water
quality. The definition of significant
lowering of water quality differentiates
between BCCs and other pollutants as
follows (see section VII.C.2 of the
preamble for a detailed discussion of the
• definition of significant lowering of
water quality and its implications): Any
increase from the baseline rate of mass
loading of a BCC is significant lowering
of water quality; and for pollutants other
than BCCs, any increase in the
permitted levels (or otherwise-allowable
mass loading rate) unless, such an
increase would have no effect, or a de
minimis effect, on the receiving water,
is significant lowering of water quality.
For point source discharges, examples
would include an increased effluent
load limit for a non-BGC in a reissued
NPDES permit, where such an increase
would have greater than a de minimis
effect on the receiving water; or for
BCCs, a deliberate action by a permittee,
such as addition of a new production
line, that would result in an increased
mass loading rate of a BCC above the
baseline loading rate for the pollutant as
established in the permit.
As regards BCCs, when discussing
NPDES permit issuance, at this poinHn
the process the permit issuance , '.
authority will have defined the
applicable "baseline" (i.e., the lowest of
either the existing limit, the "new" • '-
technology-based effluent limit, the
"new" water quality-based effluent
limit, or existing effluent quality), and
any increase from this "baseline" that is
requested by the permittee. The mass
loading rate will be restricted to this
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20891
"baseline in the permit unless the
permittee justifies the increase to the.
satisfaction of the permitting agency,
after the opportunity for public input,
through the antidegradation process set
forth in the proposed Guidance. The
baseline for a BCC could, howeverr be
adjusted without an antidegradation
demonstration to account for an
increase in discharge volume that
results hi an increased rate of mass
loading of a BCC pollutant due solely to
the presence of that pollutant in the
intake water.
Where independent regulatory
authority requiring compliance with
water quality standards already exists,
other regulated actions that may result
in an increased rate, of mass loading of •
pollutants and, potentially, the
significant lowering of water quality
would also be subject to antidegradation
review. Review of such proposed
actions by the regulatory-agency should ,
determine whether the action has the
. potential to significantly lower water
quality, and, if so, the action is required
to go through the antidegradation
process. Depending'on Federal, State
and Tribal authorities, such,aclivities
may include actions, such as changes in
land use, which result in increased
honpoint pollutant runoff or removal of
a riparian buffer strip which may allow
increased agricultural runoff. Where
there is regulatory authority requiring
compliance with water quality
standards, regulatory agencies • . •
permitting ah- emissions (subject to
section 112{m) of the Clean Air Act or
similar State authorities) should
consider the potential for significant
lowering of water quality, and if
applicable, subjected to an •- '
antidegradation review. EPA does not
intend through, the proposed Guidance
to require compliance with '" ,." '•
antidegradation provisions where
independent regulatory authority
requiring compliance with water quality
standards does not already exist.
:' b. Characterize the Receiving Water.
The antidegradatioa guidance
establishes differing restrictions oh the
.- lowering of water quality and
requirements for an antidegradation
review depending on both the quality of
the receiving water and the character of
its use designation. ONRWs are
identified at this point in the process;
all.qther waters are characterized
; pollutant by pollutant as either
achieving or not achieving .the :
applicable fishable/swimmable water
quality criteria defined elsewhere;in the
proposed Guidance. Where the water
quality is achieving the water quality
criteria for a pollutant, that water is
considered a HQW with respect to that
pollutant. Other special designations
applicable to Lake Superior are
discussed separately in the proposed
Guidance. Two outcomes are possible, ,
and resulting implications are as
follows; •
i. Waters whose quality does not
achieve the applicable water quality
criteria for any parameter cannot be :'
lowered in Water quality with respect to-;
that parameter. ONRWs cannot be
lowered in water quality except for
lowering of water quality related to
short-term, temporary (i.e., weeks or
months) activities. That is, there can be ,
no long-term change in ambient Water
quality hi ONRWs except for
improvement; or , :
ii. Actions that may significantly
lower water quality with regard to a
pollutant for which that water is a HQW
can only be allowed if an
antidegradation demonstration is'.,
provided and the regulatory agency
determines that it adequately supports
the lowering. ..
C. Activities Covered by the Great Lakes
Antidegradation Guidance > :
The antidegradation guidance applies
to any activity over which independent
regulatory authority requiring •.
compliance with water quality
standards exists, that may result in.a
lowering of water quality in any water
body in the Great Lakes System. The
activities addressed include those
resulting in point source discharges of
pollutants to a water body and those
that result in npnpoint loadings of
pollutants to a water body. As discussed
in detail hi B.3.a above and C.3 below,
EPA expressly intends for this proposed
Guidance to be applied to npnpoint
source activities, to the extent that
regulatory authorities exist, but this
proposed Guidance does not create any
new regulatory authorities.
The proposed Guidance establishes an
antidegradation policy that differs in
certain respects from the existing
Federal policy to account for the
characteristics of the Great Lakes
System, while retaining the basic
framework of the Federal regulation. As
is the case with the Federal regulation,
the Great Lakes Antidegradation '
Standard establishes differing levels of
protection against degradation based on
the water quality in the affected water
body. , . ., ••--..
1. Distinction Between High Quality
Waters, Outstanding National Resource
Waters, and Other Classes of Waters
a. Existing Federal Policy. EPA has
defihed'a "tiered" antidegradation;
approach for the protection and
maintenance of water quality. The
Federal antidegradation policy at 40
CFR 131.12 estabh'shes three tiers of ,
protection on the lowering of water
quality in a water body and a fourth
requirement apph'cable to thermal
discharges.
The first tier, applicable to all waters,
requires protection and maintenance of
all existing uses of the water body and :
the level of water quality necessary for
those uses. Under tier 1, water quality
in any water body can be lowered only
to the point at which all existing uses
are still fully protected. It is not ,
permissible to allow water quality.to be
lowered to the extent that an existing or-
designated use is impaired. Under
existing Federal policy no justification
is required in order to lower water
quality to the level necessary,to
maintain the "existing use." . '
The second tier provides protection of
actual water quality in water bodies that
support the propagation of fish, '
shellfish, and wildlife and recreation in
and on the water ("fishable/ - "
swimmable"). Limited degradation of
such HQWs may he allowable if ,.
necessary for important social and
economic development in the areas hi ;
which the waters are located, butbnly
after pubUc-involvement and ;
intergovernmental coordination, and
only as long as the water quality
remains adequate to be "fishable/
swimmable" and fully protects existhig
uses."•• •-'... /' '•- " .-'• ' . '.. "•_ - '- -
The third tier affords special
protection to waters that have been
designated Outstanding National .
Resource Waters [ONRWs) by the States
or Tribes. The water quality in ONRWs
must be maintained and protected.
Short-term temporary, changes may be
consistent with that level of protection.
b. GLWQI Guidance. The Great Lake&
antidegradation standard in the •-•;-'••
proposed Guidance retains the tiered
structure of the Federal policy, but is
more specific hi certain respects.
. The first provision requires, in part,
that the water quality necessary to .
protect existing uses be maintained and
protected. As with the Federal policy,
this provision is intended to ensure that
under no circumstance is the water
quality reduced to the extent that a
criteria derived tq protect an existing
use is exceeded. The proposed
Guidance explicitly refers to the
definition of existing uses found in the
Federal water quality standards
regulations, hi large part to distinguish
the application, in this provision of
existing uses from designated uses.
During Work Group deliberations on the
proposed Guidarice,:concerns were
raised by several parties that the Federal
' policyhad been incorrectly interpreted
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by many States around the country as
applying only to designated uses, as
they are defined by the water quality
standards regulation. Further concern
wqs expressed that designation of uses
by States or Tribes would not
thoroughly cover all existing uses of a
water body. The intent of the language
chosen for the proposed Guidance was
to clarify the effect of the language in
the Federal policy and ensure that
deficiencies in the State or Tribal use
designation procedures would not limit
the protection to be afforded water
quality under the Great Lakes
antidegradaUon guidance. For the
purposes of this proposed Guidance, for
any water body in which the water
quality attained on or after November
28,1975, is equal to or better than that
required to support a specific use, that
use is considered an existing use,
whether or not it has been so designated
in a State's water quality standards. In
no case can the water quality be lowered
below that level required to protect and
maintain such existing uses.
The first provision of the Great Lakes
antidegradaUon standard differs frc-m
the existing Federal policy in that it
explicitly prohibits the lowering of
water quality in situations where either
an existing or a designated use is
impaired. The Federal policy does not
include the designated use reference.
This prohibition is applied on a
pollutant by pollutant basis and serves
as a restriction on the specific pollutant
or pollutants that are impairing the
designated use. EPA considers a water
body to be impaired where the water
quality criterion necessary to maintain
tho existing or designated use for a
pollutant or pollutants is exceeded.
While this proposed provision differs
from the existing Federal
antidegradaUon policy on its face, it is
not more stringent than secUon
301(b)(lKQ of the CWA or the other
regulations that EPA has adopted to
protect water quality. In particular, the
existing water quality-based permitting
regulation (40 CFR 122.44(d)(l)) for the
NPDES requires the development of
affluent limitations that achieve the
water quality standards applicable to
the receiving water. Similarly, the
regulations (40 CFR 130.7) and guidance
on the establishment of total maximum
daily loads, wasteload allocations, and
load allocations require that applicable
water quality standards be attained and
maintained. Thus, the prohibition in the
proposed Guidance on the lowering of
water quality in situations where a
designated use is impaired simply
brings the antidegradation guidance into
explicit conformance with other
regulatory requirements regarding the
protection of water quality. In the
context of the whole of the proposed
Guidance, this provision would
preclude the lowering of water quality
for a pollutant or pollutants in '
situations where the concentration of
the pollutant or pollutants exceeds the -
proposed Great Lakes water quality
criteria.
EPA also believes that it would be
consistent with the policies of the
GLWQA to prohibit any lowering of
water quality in those waters in the
Great Lakes System which do not meet
the goal uses listed in section 101(a) of
the CWA for the pollutant or pollutants
that impair those uses. The CPA
requires that the proposed Guidance not
only be consistent with the CWA, but
also conform with the objectives of the
GLWQA. The purposed the GLWQA is
to restore and maintain the chemical,
physical, and biological integrity of the
waters of the Great Lakes Basin
Ecosystem. Among its objectives is the
restoration of beneficial uses, regardless
of whether they are designated uses.
The term beneficial uses is not
specifically defined in the GLWQA;
however, impairment of beneficial uses
is explicitly defined in Annex 2 to the
GLWQA as adverse effects on a list of
uses. Among the listed beneficial uses
that might be impaired are uses that are
analogous to the fishable/swimmable
uses in the CWA. EPA believes that it
is reasonable to conclude that the
beneficial use provisions of the GLWQA
'encompass the relevant portions of the
fishable/swimmable goals of the CWA.
EPA considered an explicit proposal
prohibiting any lowering of water
quality in those waters in the Great
Lakes System which do not meet the
goal uses listed in section 101(a) of die
CWA for the pollutant or pollutants that
impair those uses. Such a provision
would have served the objectives of the
GLWQA by working toward the
restoration of beneficial uses. It was
based on an ecosystem approach, taking
into account the unique characteristics
of the Great Lakes System, where the
whole is only as healthy as its parts.
While the allowance of increased .
discharges with only a localized effect.
might be acceptable in the context of a
different aquatic system, an argument
can be^nade that in order to account for
the unique characteristics of the Great
Lakes System (see Great Lakes States'
Experience, A.l.c. above), any increased
addition of a pollutant or pollutants to
a waterbody in the Great Lakes System
which has not attained the beneficial
uses for that pollutant or pollutant
should be prohibited. Where the water
quality standards for fishable/
swimmable uses are not achieved, the
beneficial uses are likewise impaired. «
This provision is not proposed in the
proposed Guidance because EPA
believes that it would be redundant
with the provisions protecting existing
and designated uses discussed above.
That is, the existing uses are, or the
designated uses will be, fishable/
swimmable. EPA may reconsider this
position if other parts of the proposed
Guidance change such that the above
redundancy no longer exists.
The second tier or the Great Lakes
antidegradation standard is identical to
the existing Federal policy in most •
respects. Both require the protection
and maintenance of water quality that
exceeds (i.e., is better than) the level
necessary to support the propagation of
fish, shellfish, and wildlife and
recreation in and on the water, except
in limited circumstances. In both, such,
circumstances are limited to those in
which the State finds, after full
satisfaction of intergovernmental
coordination and public participation
provisions of the State's continuing
planning process, that allowing lower
water quality is necessary to
accommodate important economic or
social development in the area in which
the waters are located. Finally, both
require that in allowing such
degradation, the State assure that water
quality adequate to protect existing uses
is fully maintained, and that there is
achieved the highest statutory and
regulatory requirements for all new and
existing point sources and all cost
effective and reasonable best
management practices for nonpoint
source control?. The information that is
developed and utilized to make a
decision about the lowering of water
quality in a high quality water is termed
an antidegradation demonstration.
The Great Lakes antidegradation
standard is more specific than Federal
policy in one respect, however. Whereas
the existing Federal policy is silent
regarding the manner in which water
quality is assessed to determine if it
exceeds the level necessary to support
the propagation of fish, shellfish, and
wildlife and recreation in and oh the
water, the Great Lakes standard
explicitly requires that water quality he
assessed on a pollutant-by-pollutant
basis. Under the Great Lakes
antidegradation standard, where, for any
parameter, the water quality exceeds
that level necessary to support the,
propagation of fish, shellfish, and ""'
wildlife and recreation in and on the
waters, that water shall be considered
high quality for that parameter and that
quality shall be maintained and
protected, except when, as described
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20.893
above, an antidegradation
demonstration adequately justifies the
lowering of water quality.
This approach is consistent with
National guidance, which indicates that
"all parameters do not need to be better
quality than the State's ambient criteria
for the water to be deemed a high r
quality water" and that EPA believes
that "it is best to apply antidegradation
on a pollutant-byrpollutant basis." -
("Application of Antidegradation Policy
to the Niagara River", memorandum: ,
from Martha G. Prqthro, Director, Office
of Water Regulations and Standards to
Richard L. Gaspe, Director, Water ;
Management Division, Region II, dated
August 4,1989, which is available in
the-administrative record for this .
rulemaking). The rationale provided for
this recommendation is that other
approaches would result in "a potential
., for,a large number, of waters not to
receive antidegradation protection
which is.important to attaining the goals
• of the Clean Water Act to restore and
maintain the integrity of the Nation's
waters." .• - .••''• -• T
The pollutarit-by-pollutant focus on
• water quality also represents a
reasonable, workable approach to
antidegradation in the context of the
water quality criteria for the Great Lakes
System that are'being propose'd in the
proposed Guidance. These criteria are
! intended to support the existing
fishable/swimmable use of the Great
Lakes System waters and create a de
facto designated fishable/swimmable
use for the Great Lakes System, Where
such criteria are achieved, the water is,
for those pollutants, .of a quality
sufficient to support fishing and
swimming, and is high quality. There is
no opportunity,to lower water quality
for the pollutants in waters where the
criteria for those pollutants are riot
achieved. -:
EPA requests comment on an
"alternative approach to assessing water
quality that would look at water quality
as an "all or nothing" proposition,
based on whether or not all applicable
numeric water quality criteria are met.
Under such an approach, failure of any
pollutant to achieve the water quality
criterion would indicate that the water
- body was not supporting the use that
the criterion was designed to protect
and, therefore, could not be degraded
with respect to any pollutant. The :
criteria proposed establish a de,facto
, fishable/swimmable designated use for
the entire system. The "all or nothing"'
approach would say that if any . r
pollutant exceeds one of the Great Lakes
criteria, the water body would not be
supporting the designated use. Because
there are substances in the Great Lakes
System that presently exceed the Great
Lakes criteria, the "all or nothing".
approach would; from the outset,
preclude any lowering of water quality
for any pollutant, and would continue -
to do so until such time assail criteria
are met. EPA believes that the proposed
Guidance is more reasonable than this -
alternative because, in combination
with the implementation procedures
proposed in appendixFto part 132, it
would require that loadings of
pollutants not supporting the designated
use be restricted (i.e., the
antidegradation procedures would
prohibit any additional lowering of
water quality-for such pollutants}* but
would recognize that for other
pollutants unused assimilative capacity
exists such that the loadings for such
substances could be increased and '
criteria for those pollutants still
achieved, EPA further believes that the
proposed approach is more appropriate,
in light of the national water quality- •
based permitting approach (40 CFR
122.44(d)(l)),wMch requires" controls
on pollutants the discharge of which has
the reasonable potential to cause or
contribute to ah exceedance of State
water quality criteria, but,does not
require controls on, or prohibit .
.increases in the discharge of, other
pollutants. , ; • . .;>-' . ;
• EPA requests comment on a second
alternative approach that would also
look,at whether all criteria were being
met in a water body in order to :
determine the level of protection ;.
provided by antidegradation. In this
approach, if any pollutant was
exceeding an applicable criterion, water
. quality could still be lowered with
respect to other pollutants after ah
antidegradation demonstration-review.'
The antidegradation demonstration
would; however, be less rigorous, than if
all the pollutants'iri the water body were
achieving applicable criteria.
• As with the all or nothing approach '
described above, under this approach ,
one would"determine that a water body
was not high quality if any pollutant .
exceeded an applicable criterion.
However, the lowering of water quality
for all pollutants would not be •
prohibited when any pollutant exceeds
a criterion. Instead, it would allow for
lowering of water quality for those
pollutants that were meeting criteria.
This approach also differs from the
proposed approach, which would
similarly allow for lowering of water
quality for such pollutants, in that it
would require a less rigorous
antidegradation demonstration in such
cases. This alternative might be viewed
as a middle ground between the all of
nothing approach and the proposed
approach* or a tier IVfc- level of ._ • •
protection, in situations where waters
are not meeting criteria for some '
pollutants,,but are meeting criteria for
others, EPA welcomes comment on this
approach, particularly with regard to the
level of antidegradation demonstration
that should be required to justify
lowering of water quality in the
situation it covers. EPA is also
interested in whether cpmmenters .
believe that such an approach would be
adequately protective of the Great Lakes,
System. • t \ .•
, EPA requests comment on a third
alternative that would rely on a generic
measure of water quality as opposed to
water quality criteria for individual
pollutants. Under such an approach, a
State would use a measure of water
quality that integrates chemical water
quality criteria, biological criteria, and
other appropriate criteria to assess the
quality of a water body and determine
if it'is a high quality water subject to the
tier 2 level of protection. Such an
approach could also potentially be used
to assess whether water quality is
significantly lowered as a result of an
increased discharge to a water body.
Such an approach is not proposed in the
proposed Guidance because.EPA is
unaware of; any such generic measures
that adequately Integrate all of the
subtle effects on rwater quality that are
captured by the independent
application of pumeric water quality
criteria and other appropriate State
derived water quality criteria. The
reader is-referred to EPA's June 19,
1991, "Policy on the Use of Biological'
Assessments and Criteria in the Water
Quality Program" and EPA's March
1991 "Technical Support Document for
Water Quality-based Toxics Control",
/which are both included, in the
administrative record for this
rulemaking, for a more complete -
discussion of the subject of independent
applicability. Nonetheless, EPA would
be interested in any new information
that mightaddress the applicability of
such an approach in the context of
antidegradation, and encourages
commenters tcf provide such
information. •".'•.- :
EPA also requests comment on a
fourth alternative approach for defining
water quality^ not proposed in the
proposed Guidance, that would allow
the evaluation of mixtures, rather than
individual pollutants, jThis approach
would evaluate the net effect of a
discharge on water quality and:
determine whether die discharge
improved or lowered water quality on
thewhole. \." ;.-..'' ;'•-
Under a mixture approach, a _ '
discharger could demonstrate thatthe •
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effects of increasing the discharge of one
or more individual pollutants in a
discharge would be offset by a
concurrent decrease in one or more
other pollutants. Using a technique such
as toxicity equivalency factors (TEFs),
the discharger would have the
opportunity to show that the net toxicity
or adverse effect on water quality of the
Soposed discharge would not be greater
an the current discharge. If successful
in such a showing, the permitting
agency could determine that water
quality would not be significantly
lowered and the change in the discharge
of pollutants to the water body would
not be subject to an antidegradation
demonstration.
The mixture approach is of interest
because it would allow for trading of
pollutant loadings to most efficiently
maintain water quality. The approach
proposed in the proposed Guidance
would require that the change in the
loading of each pollutant be evaluated
separately to determine if it is necessary
for important social and economic
development. In contrast, the mixture
approach would not require an
antidegradation demonstration when
some pollutant loadings were proposed
to increase provided that others were
reduced and the net effect was
determined to be no adverse change in
water quality. Because it would allow a
regulated entity to determine where it
could most efficiently reduce or prevent
pollutant loadings, with the incentive of
avoiding antidegradation demonstration
requirements, the mixture approach has
the potential to be less costly than other
approaches while still maintaining or
improving overall water quality.
Concerns with implementation of the
mixture approach have led EPA to not
propose it fix the proposed Guidance.
Thasa are described below and EPA
invites comment on each.
The mixture approach requires that
the toxic effects of the chemicals in a
discharge interact in a known way to
produce a specific effect. The subject of
odditivity of toxic effects and the
development and use of TEFs are
discussed in more detail in section
Vin.D. of the preamble. These concepts
ware considered for inclusion in the
Great Lakes Guidance, but the proposed
Guidance does not provide for their use.
EPA has concerns regarding the
practical application of these concepts,
in particular as they would be applied
in complex effluents. To determine the
net toxic effect of a discharge requires
that the pollutants in the discharge have
comparable toxic endpoints, which is
not necessarily the case for many
pollutant mixtures in effluents. TEFs
have been used to relate toxicities of
homologues within families of
pollutants, such as the chlorinated
dibenzo-p-dioxins, or between
toxicologically similar families, such as
the chlorinated dibenzo-p-dioxins and
the chlorinated dibenzofurans. TEFs
may also be applicable to other cla'sses
of pollutants, such as metals, but their
applicability would require that the
pollutants have similar toxic effects and
the same mode of action. Therefore, the
use of TEFs would appear to have
limited applicability for many pollutant
mixtures in effluents. While the use of
whole effluent toxicity as a measure of
the effect of a mixture is appropriate in
addressing effects on aquatic life, it does
not address effects on human health or
wildlife, and does not address all toxic
endpoints. Use of whole effluent
toxicity alone, therefore, would not form
the basis for an acceptable mixture
approach. EPA invites comments and
suggestions as to how these technical
issues could be addressed.
To accurately assess the overall effect
of a discharge on water quality, the
mixture approach could require that a
number of pollutants in the discharge be
factored into the analysis to determine
the net change in water quality. This
analysis could prove to be burdensome.
In addition, in order to maintain the
specific pollutant discharge reductions
which offset the increases in other
pollutants, the mixture approach could
require the establishment of limitations
'on substances that would otherwise not
have required limits. The Clean Water
Act and Federal regulations currently
define the minimum requirements with
respect to pollutants that must be
limited to protect water quality (40 CFR
122.44(d){l)), and the guidance
proposed in procedure 5 of appendix F
to part 132 provides additional direction
on this decision. EPA invites comments
and suggestions on how interactions of
pollutants could be assessed and .
considered within the context of the
Antidegradation Policy to address
mixtures of pollutants, and on how to
establish guidelines on the pollutants to
include in a mixture analysis. EPA is
also interested in information on current
practices that might be used to help set
such guidelines.
2. Significant Lowering of Water Quality
For'those waters in the Great Lakes in
which the water quality exceeds the
levels necessary to support the fishable/
swimmable goal of section 101(a)(2) of
the Clean Water Act, termed high
quality or tier 2 waters, the Great Lakes
Antidegradation Guidance procedures
identify the criteria that must be
satisfied before a decision can be made
to allow water quality to be lowered
significantly. EPA and the Great Lakes
States have chosen to prioritize actions
that pose a threat to the protection and
maintenance of water quality in high
quality waters by focussing the
proposed Guidance on "significant
lowering of water quality." The
proposed Guidance requires that high
quality waters (HQWs) not be
significantly lowered in quality unless
justified to the satisfaction of the
regulatory agency through an • ., .'. .
antidegradation demonstration.
Significant lowering of water quality
is definedln the proposed Guidance.
The definition differs for
bioaccumulatiye chemicals of concern
(BCCs) and all other pollutants. The
BCCs and the rationale for giving such
chemicals a higher priority in the Great
Lakes System are topics discussed in
detail elsewhere in the proposed
Guidance. In general, any increase in
the rate of mass loading of any BCC is
considered to result in a significant
lowering of water quality. The only
exception to this rule occurs when the
increase in the observed mass loading
rate of a BCC is riot associate'd with a
discernable action at the source (point
or npnpoint) of the BCC, and is,
therefore, likely to be an apparent rather
than real increase.
The term "action" is to be interpreted
very broadly and will include, for point
, sources, activities or combinations of
activities that contribute pollutants
(BCCs) to the waste stream, and thereby
the water body, such as, but not limited
to, creation of a new source, addition of
a new process or product line at an
existing source, expansion of processing
capacity, modifications of the waste
handling or treatment processes,
changes in.raw materials, and new
sanitary or industrial hookups to a
municipal sewer system. Generally,
simply increasing the volume of the
discharge with no addition of a BCC
pollutant to the waste stream is not
considered an action that would trigger
an antidegradation demonstration.
Similarly, for nonpoint sources, where
independent regulatory authority
requiring compliance with water quality
standards exists an action might be a
new construction activity or
development that contributes new or
increased pollutant loading from
nonpoint sources or installation of a
new factory or incinerator that might be
a source of air pollutant fallout into the
Great Lakes System. ' '" . •
The link in the definition between an
increase in the rate of mass loading of
a BCC and a discernable action is
intended to prevent apparent increases
in the rate of mass loading from
triggering a full antidegradation
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20895
demonstration. EPA and the States were
concerned that at times little data would
be available to characterize baseline
;mass loading rates at the time decisions
were being made regarding NPDES
permit requirements or other such
control requirements. Subsequent
monitoring of the mass loading rates
might reveal, an increase above that ,
indicated by the analysis of the initially
available data, due solely to data
variability and not to an actual increase
in the rate of mass loading. To address
this concern, the definition provides
that an increase in the measured rate of
mass loading of a BCC must be tied to
an action at the source of the pollutant
for it to be considered significant
lowering of water quality that requires
an antidegradation demonstration. This
concern was also considered in the
development of alternative control/
requirements that could be imposed on
an entity to maintain water quality (e.g.,
existing effluent quality restrictions),'.
which are discussed later in the :
proposed Guidance.
, For pollutants other than BOCs,
significant lowering of water quality is
, generally considered to occur whenever
a source seeks a change in its permit,
limits (or a change above a de minimis '
, increase in the rate of mass loading). For
nonpoint sources, where independent
regulatory authority requiring
compliance with water quality
standards, a significant lowering of
water quality is generally considered to
occur whenever the rate of mass loading
authorized by^ the governing nonpoint
source program is increased. Two
exceptions to this general rule exist for
noii-BCC pollutants. The first exception
: occurs when the ambient concentration
o.f the pollutantln the affected water
body, outside of the designated mixing
zone, where applicable, will not
increase. The Director may'also look at
the effect of the increase on the
sediments and biota to determine if they
will be adversely affected. The second
exception may result where the .increase
is de minimis, or insignificant, in
comparison to the unused assimilative
capacity of the receiving water for that
pollutant. The de minimis
demonstration is discussed in detail
later in this notice.
EPA .believes that the above definition
of significant lowering of water quality ,
for non-BCC pollutants is adequate to
maintain and protect water quality in -.
the Great Lakes System. It does not
undercut the requirement that
limitations protect existing uses, i.e.,
protect all applicable water quality .
standards. Rather, it limits the
requirement to conduct an
antidegradation review to situations
when a source sought to increase ...'
existing permit limitations on the rate of
mass loading, except as the increase is
de minimis or there would be no change
in ambient water quality, and thereby
will limit the number of actions subject
to a full antidegradation review. EPA
believes that this is an appropriate
balance between the need to protect .--"..
water quality for these, substances and
the burden, to both the regulated
community and the regulatory agencies,
of conducting an antidegradation
review. EPA welcomes comments on
this position and specifically requests
information on situations where this
provision for non-BCCs may fail to ,
adequately protect and -maintain water
quality. ,
Finally, the definition contains a
provision that allows the Director to
make case^by-case determinations
regarding the significant lowering of
water quality based on best professional
judgement. This provision is intended
to give the Director flexibility to
^designate actions that might have fallen
outside of the other provisions of the
definition, yet are considered by the
Director to be important enough to ,
warrant a full antidegradation review.
EPA emphasizes that the definition of
significant lowering of water quality is
intended to cover actions thatlower
water quality. It is not EPA's intent to
cover, under antidegradation, increased
discharges that do not contribute ....
pollutants to the water body.
Furthermore, for BCCs the increased
rate of loading must be associated with
an action by the regulated entity. As
discussed above, EPA intends that the
term "action" be associated with
activities that contribute pollutants to
the water. . . * ', •
For example, the antidegradation
guidance is intended to cover the
situation in which an industry that
discharges BCCs to the Great Lakes
System increases its rate of production,
and with the production, the rate at
which these pollutants are added into
the water via its waste stream. In
contrast, another situation may have an
industry that draws cooling water from
a water body in the Great Lakes System,
and discharges that water back into the
same water body without adding or J
removing any BCGs^ If the industry
wanted to increase the amount of
cooling water it pumped through the '
facility, the increased rate of BCC
loading in the effluent due solely to
background, pollutants from the water
body would not trigger an
antidegradation demonstration.
The determination of whether a
discharge results in the significant
lowering of water quality differs from
decisions regarding whether a pollutant
must be limited to protect water quality
criteria and at what level :the limitation
is established. The latter decisions are
addressed by the implementation .
procedures proposed in the proposed
Guidance. The reader is referred to the
. preamble discussion of procedure 5, .
"Reasonable Potential to Exceed
Numeric WQSs" (see section Vin.E of
appendix F to part 132) for additional
information.
EPA believes that the rule is
sufficiently clear in these areas, but '
would welcome comment on whether
the rule requires clarification.
Commenters are encouraged to provide
suggested changes to the rule that would
accomplish the clarification.
EPA requests comment on the
• proposed approach to defining :
significant lowering of water quality and
is particularly interested in comments
on the requirement that an increase in
the rate of mass loading of BCCs be tied
to an action for it to be considered a ;
'" significant lowering of water quality. In
particular, does the definition place an
undue burden on the regulatory agency •
to. identify a specific causative action or
actions, or, alternatively, on the
regulated entity to prove.that no action
• occurred? Also, where data exist? and
are considered by the regulatory agency.
adequate to demonstrate a long-term
. gradual increase in the rate of mass -
loading of a pollutant, should such an
increase be considered a significant:
lowering of water quality even when no
specific causative action or actions can
be identified? Such situations could:
result from aging waste treatment
processes, which could be considered
an "action", by the Director. EPA
welcomes comment-on whether the
proposed Guidance should be clarified
to more explicitly address this and other
similar situations.
EPA also requests comment on
whether the definition of significant
lowering of water quality should
distinguish between BCGs and other,
- pollutants. In particular, EPA is
interested in whether BGCs would be
adequately controlled if the same
definition of significant lowering of
water quality as is applied to other
pollutants were to be used for BCCs.
Such an approach would have the effect
. of tying the definition of significant
lowering of water quality for all
pollutants to increases in permit limits.
' It would provide opportunity for a de
minimis demonstration, for increases in
limitations on BCCs. It would also -
provide opportunity for an entity to
attempt to demonstrate that the ambient
concentration of the BCC would not
increase. Other possible approaches
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might restrict application of the de
minimis test or me demonstration of no
ambient change, or both, to non-BCCs,
while still tying the definition of
significant lowering of water quality for
any pollutant to permit limit increases.
EPA Invites comment on these
approaches and suggestions for others
mat should be considered. EPA also
welcomes suggestions regarding any
changes or specific requirements that
should be made or added to the de
minimis test and the demonstration of
no ambient change to address BCCs if
th« definition of significant lowering of
water quality were to be changed as
discussed above.
3. Covers All Pollutant Sources CPoint
and Nonpolnt)
As has already been discussed briefly,
tho antidegradation guidance covers any
regulated activity, the result of which
might be tfaa lowering of water quality
in the Great Lakes System. Such
regulated activities are not limited to
programs administered under the Clean
Water Act, such as the NPDES and
* section 404 permitting programs. While
this proposed Guidance does not create
any new regulatory authorities that can
ba used by Federal, State, Tribal, or
.. local regulatory authorities in
* expanding control of pollutant sources,
* it provides them with & framework for
making consistent decisions regarding
tha protection and maintenance of water
quality within existing regulatory
authorities, where such authorities
raquiro compliance with water quality
standards, One set of mechanisms that
EPA believes will facilitate the
application of the proposed Guidance to
all sources of pollutants to the Great
Lflkos System is the Lakewide
Management Plan (LaMP) that will be
developed for each Lake. LaMPs are
required by Annex 2 of the GLWQA to
facilitate the restoration and protection
of beneficial uses in tlie open waters of
the Lakes. In addition, the CPA
establishes a schedule for the
completion of the Lake Michigan LaMP.
Tha LaMPs will provide an integrated
management tool to address all
pollutant sources and coordinate all
applicable regulatory authorities. While
EPA feels that LaMPs will facilitate the
application of this proposed Guidance,
completed LaMPs are not prerequisites
for its effective application, and
regulatory authorities cannot delay the
use of this proposed Guidance pending
the development of a LaMP, EPA
welcomes comment on alternative
approaches to clarify within the
proposed Guidance that it is applicable
to both point and nonpoint sources of
pollutants to the Great Lakes System,
and to ensure that it is utilized in
regulatory decision-making whenever
appropriate.
4. Exemptions
The antidegradation guidance defines
several actions or situations that will .
generally not be considered subject to
the restrictions imposed by the
antidegradation procedures. These
exemptions are intended to cover
actions that might lower water quality
for a short duration, where the lowering
is reversible, especially where the action
will improve water quality over the long
term. They also address emergency
situations, which require immediate
response to protect public health or
welfare. The Director has the ability on
a case-by-case basis to require that an
otherwise exempted action comply with
the antidegradation procedures.
There is a broad exemption provided
for actions the effect of which is limited
to a short-term, temporary lowering of
water quality. The Federal
antidegradation policy allows short-
term, temporary changes in water
quality in ONRWs, with no requirement
for an accompanying antidegradation
demonstration, a provision mat was
carried over into the Great Lakes
antidegradation guidance. EPA believes
that it is reasonable, since short-term,
temporary lowering of water quality is
allowable in the category of waters
given the very highest degree of
protection, the ONRWs, that similar
allowance should be made for high
quality waters.
The proposed Guidance places
bounds on the timeframe that will be
considered acceptable for an event to be
considered a short-term, temporary
lowering of water quality. For the effect
of an action to he considered a short-
term, temporary lowering of water
quality, the effect must be limited to
weeks or months in duration. This
definition is the same as has been
considered by EPA when drafting other
guidance on water quality standards. It
provides considerable flexibility to the
Director to account for the specific
characteristics of the pollutant involved,
the receiving water, rate of mass
loading, and so on, when deciding on •
whether the lowering may be short-term
and temporary. While not explicitly
excluded by the timeframe specified,
actions that lower water quality for a
year or more should only rarely be
considered short-term and temporary.
Exemptions are also provided for
certain emergency situations, which
may result in a lowering of water
quality. The first such exemption
involves non-prohibited bypasses of
wastewater treatment systems. Bypasses
are defined and generally prohibited in
the Federal NPDES regulations at 40
CFR 122.41(m). The regulations make
exception to the. general prohibition for
instances hi which a bypass is
unavoidable to prevent loss of life,
personal injury, or severe property
damage, and there is no feasible
alternative to the bypass. Similarly, the
guidance provides an exception for
Comprehensive Environmental
Response, Compensation, and Liability
Act (CERCLA) response actions and
those taken under similar Federal or
State authorities. CERCLA response
actions are taken to alleviate
emergencies resulting from/releases into
the environment of hazardous
substances, and pollutants or
contaminants which may present an
imminent and substantial danger to
public health; or welfare. EPA believes
that it'would generally be infeasible and
inappropriate to hold these emergency
situations to the restrictions and
procedural requirements of the
antidegradation guidance.
The exemption from the
antidegradation procedures does not
exempt such actions from other
requirements with which they are
expected to comply. For instance,
CERCLA response actions are required
to comply with all applicable, or
relevant and appropriate requirements,
a term that is defined in the Federal
regulations and includes all State water
quality standards applicable to the
water body. Similarly, the NPDES
regulations prohibit bypasses in all but,
a very limited number of situations. The
exemption to the antidegradation
procedures does not alter the bypass
prohibition in the NPDES regulations,
but only provides relief from the
antidegradation requirements for those
bypasses not otherwise prohibited,
EPA welcomes comments on the
exemptions identified in the proposed
Guidance. In particular, EPA is
interested in comments on the
exemption for short-term, temporary
lowering of water quality regarding both
the appropriateness of such an
exemption and the timeframes
identified.
EPA also considered a broader
exemption for remedial actions taken
pursuant to CERCLA, or other similar
Federal or State authorities.. Remedial
actions differ from the response actions
discussed above in that they are
generally long term, non emergency
clean up activities associated with
historical contamination. Remedial
actions may improve water quality over
the long term but result in a temporary
lowering of water quality in the same
surface water body over an extended
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20897
period (i.e., longer than would satisfy
the requirements for an exemption for
short-term, temporary lowering of water
quality). In many instances the
contamination remediated by such -
actions will be adversely affecting a •
surface water body, whether through
contaminated runoff, ^contaminated
•groundwater percolating into the.surface
water, in-place sediment contamination,
or other similar mechanism. Remedial
measures are generally designed, to
control or eliminate the source of the
pollutants and clean up the
contamination. However, the immediate
result of a remedial action, in particular.
while it is being conducted, may be a
lowering of water quality, for instance
through the discharge or release of the
contaminants from a ground water ''
treatment system into a surface water,
often the same water'body that is
already adversely affected by the
contamination. This temporary lowering
often extends beyond weelcs or months,
but may result in long term •. •- '
improvement in; surface water quality.
Even where the same water body is
temporarily degraded, such discharges
must ensure protection of water quality
. standards as they occur, and the net
effect over the longer term may be
beneficial to water quality. Other special
' provisions discussed later in the
proposed Guidance ^regarding the
antidegradation demonstration and
' decision might affect the need for.any
exemption for remedial actions, EPA
. requests comment on whether those •
special provisions are adequate or .
whether the exemptions should be
expanded to cover CERCLA remedial
actions.
5. Discharges of Fill Material in
Wetlands -
* Section 404 of the CWA regulates the
discharge of dredged or fill material into
waters of the United States, including
wetlands. Fill material means ' ,
discharged material which converts
. waters of the United States to dryland
or which changes the bottom elevation
of waters of the United States. Permits
for such discharges must be based on
the section 404(b)(l) guidelines, 40 CFR
" part 230, which require, among other .
things, that discharges not violate
applicable water quality standards and
not cause significant degradation to the
environment.
Both the Federal and proposed Great
Lakes antidegradation policies require
that existing uses be protected.
Discharges of fill material in wetlands
can be seen as automatically eliminating
the use within the filled area. Thus, a
literal interpretation of either
antidegradation policy could flatly
prohibit the issuance of any section 404
permit for a wetland fill. Since it is
logical to assume that Congress
contemplated that at least some such
permits be issued under the framework
of the GWA, EPA has interpreted the
existing use provision in the Federal.
policy to be satisfied with regard to fills'
in wetlands if the discharge does not
result in "significant degradation" of the
aquatic ecosystem as defined under 40
CFR 230.10(3 of the section 404(b)(l)
guidelines. For high quality waters, the
same "no significant degradation" level
. serves as the floor below which no
significant lowering of water quality can
be allowed. EPA requests comment on
whether the Great Lakes antidegradation
policy should be interpreted in a similar
.way. : .-'...'"". "'..'-'
P. Existing Effluent Quality
1, Background -•• •; _ ,
Controlling contamination of the
Great Lakes System by BCCs is a very
high priority of the Great Lakes States
and EPA. EPA is proposing that any
increase, above a defined baseline, in ;
the rate of mass loading of a BGC from
either a point or a nonpoint source be
considered significant lowering of water
quality. The antidegradation procedures
established by this proposed Guidance
require special controls on potential
sources of BCCs to protect against any -
unreviewed significant lowering of
water quality that would result from
such an increase in the rate of mass
- loading of a BCC. In particular, they
require that the future rate of mass
loading of BCCs be restricted to levels
that are representative of typical
operation at the time that the Director is
considering issuance, reissuance or
modification of the applicable control
document, unless an increase is justified
through an antidegradation
demonstration.
2. Options for EEQ Controls , ,
The proposed Guidance is not specific
on the control document requirements
that the Director uses to restrict the rate
of loading of BCCs, and provides the
Director considerable latitude to
establish conditions that fit the :
situation. The following discussion
describes the alternatives that the
regulatory agency can employ to.
implement the requirements of section
H.D.'l of appendix E of the proposed
Guidance, regarding the control of the
loading of BGCs, which will be termed
the existing effluent quality (EEQ)
provision.
To consistently implement the EEQ
provision of the proposed Guidance,
each State or Tribe should develop
procedures that will be followed when .:
making control docunlent decisions in
all applicable programs. The procedures
should specify the types of conditions
that will be used to establish a baseline
discharge mass loading rate for each
BCC as control documents are reissued
or BCC-related conditions are modified.
In particular, the procedures should :
serve as a crosswalk between the Great
Lakes Antidegradatipn Guidanceand .'"•••
the various regulatory programs, by
identifying which .decisions within each
• program are affected by the proposed
Guidance, the control documents •'.-.-
utilized and the types of conditions that
can be included within them. The
control document requirements ;
specified in such State or Tribal
procedures must be enforceable to
accomplish this objective. An increase
in the rate of mass loading may be ;
requested by the regulated entity in the
future and may be allowed if the
increase is consistent with the " • ,
antidegradation demonstration and
decision requirements of the proposed
Guidance.
To. determine EEQ, a pbllutant-by-
pollutant evaluation of the release or
discharge ("effluent quality") must be
conducted during preparation of a draft
control document for reissuance. All
data collected over the previous control
document term (e.g., past five years) that
are representative of typical operation
should be utilized. Discharge
monitoring reports, application ,
information, compliance sampling
inspection results, and information
requests may all provide useful
information for this analysis. Data that
reflect upsets or bypasses (such as those
situations denned in 40 CFR 122.41 for
the NPDES program) should not be
utilized.
In developing this recommendation
. EPA intends to define a data set that
would allow a permit writer to establish
what the typical loading rate from a
discharger is (i.e., how is the discharger
affecting-water quality?), while trying at
the same time to ensure the database is
large enough for meaningful analysis.
This recommendation parallels the
NPDES regulations and guidance
regarding development of production-
based limits (see 40 CFR 122.45(b)(2)(i);
• .49 FR 38031, September 26,1984; and
Training Manual for NPDES Permit
Writers, U.S. EPA, Office of Water,
January 1993, pp. 4-4 through 4-6). By
specifying the term of the preceding
control document we are trying to
ensure there are enough data points to
make the evaluation meaningful,
without making the period over which .
data were collected so long that the data
would not be representative of normal
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / j-ropo'sed. iuues
or typical operations. Where conditions
affecting the discharge are not constant
over the term, the regulatory authority
has tha flexibility to adjust the time
period over which data are considered
representative of the effluent quality at
the time of reissuance. For example, an
expansion that occurred in the last 1V2
years of a permit term would likely
result in only the last \V* years' of data
boing evaluated as representative of the
discharge at the time of reissuance. On
the other hand, if operations were
curtailed in the most recent months as
a result of a business slow-down, the
discharge data during the earlier years
of tho term maybe more representative
of typical operations.
Tho distribution of multiple data
points should be characterized using
appropriate statistical techniques.
Appendix E of EPA's March 1991 -
"Technical Support Document for Water
Quality-based Toxics Control" (TSD)
provides a good background discussion
of statistical applications to describe
effluent quality, and to develop effluent
limitations that are appropriate for the
discharge, (This document is available
in tho administrative record for this
rulemaking. Copies are also available
upon written request to the person
listed in section Xm of this preamble.)
Tho TSD provides, in appendix E, a
discussion of the derivation of effluent
limitations based on actual discharge
data (i.e., derivation of EEQ). It also
provides procedures (see Tables 2, 3 and
4) which may, depending on the data
set, be used to derive these numbers. As
explained in appendix E of the TSD, it
will generally be appropriate to use
procedures which assume that the daily
effluent data are approximately log-
normally distributed. This assumption
is consistent with the general
experience of the EPA in evaluating
effluent discharge data (see section 5.2.2
of tha TSD), but may be overridden by
tho permit writer if the effluent data
deviato seriously from this distribution.
Where this is the case, alternative
methods, such as non-parametric
statistical techniques, may be useful to
determine EEQ, Similarly, the
procedures in appendix E of the TSD
assume that the data are independent
(i.e., not correlated with one another).
Should this assumption not hold,
oltornativa statistical techniques or
other corrections may be appropriate.
Appendix E of the TSD provides some
suggestions on how this may be
accomplished.
Analytic results that are below the
quantification level should be factored
into the development of EEQ as non-
zero results using the procedures set
forth in procedure 3B of the proposed
implementation procedures (appendix F
to part 132) or other appropriate
statistical procedures (e.g., delta
lognormal procedures from appendix E
of the TSD).
Various options for incorporation of '
EEQ as a control requirement in a
control document were considered
during development of the proposed
Guidance. The EEQ control
requirements, in conjunction with any
more stringent limitations otherwise
required by the applicable regulations,
such as technology-based and water
quality-based effluent limitations in the
NPDES program, must provide complete
coverage of all BCCs. In addition, the
proposed Guidance requires that control
documents contain a condition
prohibiting the discharger from
undertaking any deliberate action which
would result in the increase in the mass
loading rate of a BCC above EEQ,
without having first successfully
completed an antidegradation
demonstration and received State
authorization for the increase. The
following discussion covers the two
principal options, which may be used
either independently or
complementarity, and a supplement
which may be used in combination with
either or both options. EPA invites
comments on these options and
welcomes suggestions regarding other
alternatives that should be considered
for EEQ controls.
a. Option 1: EEQ as Numeric Mass
Loading Rate Limitations. In this option,
a State will develop numeric effluent
limitations that will serve to restrict the
loadings of BCCs to their existing levels.
In an NPDES permit, limits will
generally be expressed as daily maxima
or weekly averages and monthly
averages. Other control document
situations may call for alternative
averaging periods.
Generally, calculations to determine
daily maximum and weekly or monthly
average numeric limitations to ensure
that effluent mass loadings of a BCC do
not increase above EEQ should follow
this approach: Using appropriate
statistical techniques, determine the
daily maximum EEQ as the upper 99th
percentile of the distribution of the
daily data, and the weekly or monthly
average EEQ as the upper 95th
percentile of the distribution of the
average of the daily data.
The resulting numbers, if more
restrictive than otherwise applicable
technology-based or water quality-based
effluent limits, should be incorporated
into the control document as daily
maximum or weekly average, and
monthly average mass loading rate
limitations. Any exceedance of such
limits would be a violation of the permit
and subject to enforcement. Entities
subject to such limitations that
anticipate that production or process
changes may result in exceedance of the
EEQ limits will need to request an
increase in the EEQ limits and justify
such an increase through an
antidegradation demonstration. When
such a request is made prior to control
document issuance, appropriate
alternate effluent limitations that are
based on the demonstration would be
incorporated into the issued control
document. Where such information
becomes available during the term of the
control document, the entity may
request modification of the control
document, subject to any applicable
regulatory constraints on such
modification, and submit supporting
information including an
antidegradation demonstration.
b. Option 2: Narrative Prohibition
Coupled with EEQ Notification
Requirement. Under this option, the
draft control document would contain
' two separate conditions that, together,
Would serve to monitor the level of
discharge of BCCs and restrict the
permittee from undertaking actions,
such as plant expansions, that would
result in an increase in the mass loading
rate of any BCC.
The first of the two conditions would
be the narrative condition (limitation)
described earlier. NPDES permit
language that would accomplish this
" it read as follows:
m _
"The permittee is prohibited from
undertaking any deliberate action,
where such action by the permittee
would re'sult in the increase in the mass
loading rate of a Bioaccumulative
Chemical, of Concern [denned and listed
elsewhere in the permit] above that
established with the issuance of this
permit. Should the permittee propose to
take such action, the permittee must
seek modification of this permit, and
provide information including an
approvable antidegradation
demonstration to support the request."
The second of the two conditions
would be a monitoring requirement
with notification triggers. This
condition would list all of the BCCs to
which it applies, the required
, monitoring frequency, and the EEQ
level (determined using the procedure
for the daily maximum limitation under
Option 1, i.e., the upper 99th percentile
of the distribution of the daily data) for
each listed pollutant. The second
condition would also contain
requirements that the permittee notify
the Director of any exceedance of an <
EEQ level (notification trigger) and that
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20899
such notification specify the suspected
cause of the exceedance, ~_
If ongoing monitoring indicates that a
substance has been discharged in excess
of EEQ, it is the permittee's
responsibility to notify the Director of
the exceedance and the suspected cause.
Failure to provide notification as
required is a violation of the permij: and
subject to appropriate enforcement --•
response. Receipt of such notification by
, the Director may prompt a review to
determine if there has been a change at
the permitted facility in violation of the
narrative condition. It may also prompt
reassessment of the EEQlevel to
determine if there is a need to modify
the EEQ notification triggerto better
reflect the actual rate of
' Should the review of any information
available to the Director, including that
submitted pursuant to the EEQ •_•
notification condition, demonstrate that
. the entity has taken an action prohibited
under the narrative, the entity would be
in violation of the narrative condition.
Such a violation would be handled in
•the same way as a violation of a numeric
limitation.
c. Supplement to Options 1 or 2:
Establishment of Discharge Prohibitions
to Maintain EEQ. In addition to the
requirements of Options 1 or 2, States
may wish to specify in the control
document that the discharge of listed
BCCs not specifically limited or
otherwise restricted in the control,
document is prohibited, or,
alternatively, that such discharge is not
authorized by the control document.
This may be a particularly attractive
alternative to a long list of pollutant
limitations for BCCs that are known or
believed to be absent in the discharge.
To adequately implement the
requirements'of section n.D of appendix
E of the proposed Guidance,
requirements under this, supplemental
action would have to be enforceable and
"tracked. The control document would
include language that clearly establishes
the prohibition or non-authorization
. and the list of pollutants to which it
applies. It would require periodic
monitoring to be used to assess
compliance. Under this'supplemental
action, the control document would
indicate that the discharge of a specific
list of pollutants is not authorized, and
specify the effect of detecting ail
unauthorized pollutant in the effluent. •
The effect may range from a violation of
a limitation as in Option 1 to the
triggering requirement as in Option 2, ;
but it would be clearly specified in the :
control document. •
3. Issues
During the Great Lakes Water Quality
initiative Technical Work Group
discussions regarding the use of EEQ
controls on BCCs to protect and *
maintain water quality in high quality
waters, numerous issues were
deliberated. In addition to comments on
the general approach to using EEQ "'
described ahove, EPA solicits comments
on the issues and decisions discussed •
below. -.
a. Punishment of Good Performers.
One criticism frequently made of the
use of EEQ limitations and control
requirements is that they are a
disincentive to good performance by a
regulated entity. In the context of an
NPDE$-permitted discharger, the
rationale for this criticism is as follows.
A "good performer" will seek to operate
its treatment processes as efficiently as
possible, or even design excess ;
treatment capacity, in order to ensure
that the technology-based and water
quality-based effluent limitations in its
permit are never exceeded."As a result
of this good performance, the effluent
quality of such a discharger is likely to
be considerably below the limitations in
its permit. The EEQ evaluation would
result in the-discharger receiving tighter,
EEQ-based limitations or control
requirements, solely because of the
discharger's good past performance. ~
Furthermore, to the extent that the EEQ
conditions are more stringent numeric
limitations on the mass loading rate of
the BCCs, that discharger would be put
at higher risk of violating the
limitations, even if it continued to
operate as efficiently as it had in the
past. Making the situation even more '_
disagreeable to those raising this issue is
the perception that "bad performers"
are rewarded by the process, because
their technology-based or water quality-
based limits would likely not be
tightened as a result of the EEQ analysis,
EPA and the Great Lakes States share
the concern that the EEQ provision not
be a disincentive to good performance,
and the proposed Guidance is written to
allow regulatory authorities the
flexibility to utilize alternatives, such as
identified above, that should help to
alleviate the concern. In particular,
Option 2 provides for permit conditions
that require notification of an. .".,
. exceedance of an EEQ level/and such
.an exceedance only results in a permit
violation when it is either not reported
or is the result of an action by the
permittee, which nas not been approved
by the regulatory agency under the Great
Lakes antidegradation decision-making
procedures. This approach still captures
the EEQ concept,but it addresses in part
the perceived disincentive associated
with EEQ limitations. In particular, the
r concern that" an EEQ limit puts a
•permittee at a higher statistically'
defined risk of a permit violation is
avoided by this approach.
In addition, EPA believes that these
concerns downplay the real risks of
being what would be considered a "bad
performer." While such a discharger
might not see tightened restrictions or
limitations on BCCs, it will still see EEQ
restrictions or limitations, in addition to
the applicable technology-based and
water quality-based limitations. " •''
Minimally adequate or poorly operated
and maintained treatment capacity or
other such characteristics that would
tend to characterize a "bad performer" .
will very likely result in a significant
probability of violation of these limits.
As EPA or the States consider the
appropriate enforcement response to
effluent limitation violations, they will
take into account the factors that
separate the "good performers" from the
"bad performers^" EPA believes "that the
increased likelihood of effluent limit ,
violations and enforcement actions that
result from being a"bad performer" will
continue to be a strong incentive for
good performance, even after EEQ
restrictions are implemented.
EPA and the Great Lakes Steering
. Committee believe that it is appropriate
to restrict the rate of mass loading of
BCCs to EEQ to protect and maintain
water quality in the Great Lakes System,
EPA is not, through the use of EEQ to
define effluent requirements or
limitations, trying to force dischargers to
install and operate additional waste
treatment capacity, but only to operate
and maintain their existing capacity so
that the rate of mass loading of BCCs
does not increase. EPA welcomes
comments on other alternative
approaches that should be considered
that accomplish this objective, but
might place less of a burden on the
regulated community, in particular the
"good performers." Also, as discussed
above, under C.2. "Significant Lowering
of Water Quality", EPA is inviting
comment on whether the definition of
significant-lowering of water quality
should, be changed to focus on permit
limit increases for all pollutants and'
thereby eliminate the focus on EEQ for
BCCs. EPA is.interested in whether ;
commenters.belieye that such a change
. would remedy the perceived
disincentive for good performance.'
b. Statistical Procedures. The analysis
of effluent data to develop EEQ
estimates requires the use of statistical
procedures. During development of the
proposed Guidance, concerns were
raised by many parties regarding the •'••'''
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procedures that should be applied and
the implications. In particular, it was
noted that no single formula could
appropriately be used on all data sets
and that all procedures would define
sorno upper bound EEQ estimate, which
would almost guarantee occasional
oxcoedances of the estimate and the
potential for violations of the
corresponding effluent limitation.
EPA agrees that no single statistical
formula will be appropriate for all
situations. Thus, the proposed Guidance
does not prescribe any specific formula
or procedure to determine EEQ. Rather,
the decision is left to be made by the
regulatory authority on a case-by-case
basis. Nonetheless, as described above
and discussed more thoroughly in the
EPA TSD, for effluent discharge data, it
will often be appropriate to apply
simple lognormal statistics to determine
EEQ. In addition, the NPDES permit
regulations specify the averaging
periods that should generally define the
permit effluent limits. Standard practice
has bean to apply the upper 99th
porcentile of the distribution of the
daily effluent data as a maximum limit,
and the upper 95th percentile of the
distribution of the average of the daily
effluent data as an average limit.
EPA notes that the proposed
Guidance does not require that EEQ be
expressed as numeric effluent
limitations. However, EPA continues to
strongly support the use of the
probability expressed above in the
characterization of EEQ. EPA has
historically used these or similar
probability levels in the context of
effluent limitations guidelines
development. Probability levels have
also bean used by EPA and the States in
tho development of individual permit
effluent limits. It is not possible to
derive numeric EEQ limits that
guarantee 100 percent compliance; with
any EEQ limit will come the statistical
probability that the limit will be
exceeded. The goal in establishing
probability levels is to allow the
regulatory agency to distinguish
between adequately operated
wastawater treatment plants with
normal variability from poorly operated
treatment plants. EPA invites comments
and suggestions on other approaches
that might be useful in place of or in
addition to the statistical procedures
discussed in establishing EEQ.
c. Data Availability and
Representativeness. Many of the BCCs
will have very little discharge
monitoring data available from which to
derive EEQ for any given source. This
arises for a variety of reasons, ranging
from simple lack of historical
monitoring requirements because the
discharger was not considered a
potential source of the BCC, to lack of
monitoring techniques sensitive enough
to measure environmentally significant
discharges. The focus of the Great Lakes
autidegradation guidance on the BCCs
raises the question of whether the
periodic monitoring of all dischargers
for the presence of BCCs should be
required. The frequency of such
monitoring would be determined by the
regulatory agency based on the potential
of the discharge to be a source of the
BCC. EPA invites comments on this
question and suggestions on the
appropriate monitoring requirements for
BCCs. EPA has estimated the potential
! cost to industrial and municipal
facilities to monitor for the presence of
BCCs in their discharges. Assuming that
all industrial and municipal facilities
monitor twice per year for BCCs having
Tier I criteria, the total annual
monitoring cost for Tier I BCCs are an
estimated $10 million.
Decisions on control document EEQ
requirements may have to be made
based on very limited data, or on data
which the regulatory agency considers
questionable. Considerable flexibility is
available to the regulatory agency to
deal with such issues. If the regulatory
agency is concerned that a BCC is in a
discharge, reasonable additional data
may be requested of the regulated entity
prior to development of the "control
document under the information
gathering authorities common to most
environmental statutes. The EEQ
conditions in the control document may
also be tailored to address the quantity
and quality of the data initially available
to determine EEQ, through the use of
restrictions other than numeric effluent
limitations. EPA believes that the
flexibility available to the regulatory
agency to implement the EEQ
requirements allows for sufficient
options to address the data availability
problems which might.arise, while still
ensuring that water quality is
maintained and protected.
d. Application to Municipalities.
During the Technical Work Group
deliberations on the use of EEQ
requirements, the issue of applicability
of EEQ conditions to discharges to
publicly owned treatment works
(POTWs) was repeatedly raised. In
particular, there was concern expressed
that such requirements would restrict
growth that had been previously
contemplated in the design and public
funding decisions involving the POTW,
It was argued that POTWs have
historically been designed, approved,
publicly funded, and constructed with a
built in growth assumption. The
regulations at 40 CFR 122.45(b)(l)
recognize this and call for the use of the
design flow to develop POTW effluent
limitations. This growth factor and the
incremental increases in pollutant
loadings accompanying growth were
part of the initial public decision to
construct a POTW, the argument went;
therefore, it is not necessary to revisit
these issues in an antidegradation
analysis.
* EPA notes that much of this
discussion occurred when the Technical
Work Group was considering requiring
EEQ limits for all pollutants, which is
not a requirement of the proposed
" Guidance. It was generally agreed that
any relaxation in existing effluent limits
that were not based on EEQ should ,
necessitate antidegradation analysis.
Similarly, any proposed expansion of
POTW facilities that may result in an
increased loading of pollutants to the
receiving water over its design life, or
the operation of a POTW beyond its
design capacity was anticipated to be
subject to antidegradation analysis. It
was also generally accepted by the Work
Group that the discharge of BCCs from
POTWs would require EEQ analysis
upon permit reissuance. These
requirements are reflected in the
proposed Guidance.
Consequently, EPA believes that the
'proposed Guidance addresses many of
the unique concerns of POTWs
associated with anticipated growth, by
only requiring EEQ conditions for BCCs
and keying the significant lowering of
water quality for all other pollutants to
increases in permit limits. EPA invites
comment on whether the proposed
Guidance adequately addresses the
issue of anticipated growth by POTWs,
and suggestions on how the proposed
Guidance might be improved in this
regard.
e. Restrictions on Actions Versus
Limitations on Pollutants. Use of the
type of conditions specified above in
Option 2 also was the subject of
considerable debate during the
development of the proposed Guidance.
Option 2 would require the use of a
narrative prohibition on the
implementation of any action by the
regulated entity which would result in
an increase in the rate of mass loading
of a BCC above EEQ. This narrative
prohibition, when coupled with
monitoring and EEQ-based reporting
trigger levels, would be expected to
prevent the significant lowering of wate
quality, just as would numeric
limitations on the BCCs. The primary
debate centered on the use of a
condition which prohibits an action
rather than directly setting effluent
limitations. A parallel concern involved
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20901
the use of narrative restrictions in lieu
of numerical limits, in general. : ;
EPA recognizes that, particularly in
the NPDES permit program, it has
traditionally focussed almost
exclusively ori the use of effluent
limitations to control discharges and
has, with limited restrictions, allowed .
the regulated entity corisidferable .
latitude in determining how to comply
with the limitations; Generally, permits
are not constructed to specify the
treatment .technologies and controls that
must be used by a regulated entity. At
first glance, the narrative prohibition on
actions by a regulated entity .that is
included in Option 2 might seem to run
contrary to this standard practice. , . • •
One reason for the traditional focus
on numeric limitations is that,
especially as involves water quality-
based permitting, it is the quality*of the
effluent that is important, not
necessarily the treatment or controls
used to achieve that quality. In addition,
one of the best measures of treatment
plant performance is the quality of the
effluent that the plant produces. In this •
sense, numeric effluent limits are often
the most sensible type of permit:
requirement to use1 to ensure proper .'
treatment system performance. '
However, even within the context of
the NPDES program; conditions are
included in permits that specify actions
that must be undertaken by the .
regulated entity in order to be in
, compliance with the permit. For
instance, permits often include
compliance schedules that specify
actions to be accomplished by the
permittee. The NPDES regulations also
provide that permits may contain
requirements for the implementation of
best management practices. Finally,
permits also currently contain
prohibitions on certain actions, such as "
bypasses. Under the Clean Water Act,
EPA is.provided with broad authorities
to establish permit conditions necessary .
to carry out the provisions of the Clean :
Water Act; such conditions;are not ;
limited to numeric effluent limitations.
. EPA believes that the Option 2 ,
prohibition on actions which would -
result in an increase in .the rate of mass .
loading of a BCC is consistent with
current.permitting practice, and well
within existing regulatory authorities. In
addition, EPA is confident that well-.,
constructed, clear narrative conditions,
can be tracked and enforced as ;
effectively as numeric limitations. .
f. Statutory Authority for EEQ.
Questions were raised during •
development of the proposed Guidance
regarding the statutory, authority upon
which EPA was relying in requiring
EEQ to be used in the development of
control document conditions.;
Antidegradation policies are clearly
authorized by the Clean Water Act (see
sections 118, as amended by the.CPA,
and 303(d». Under the Federal
antidegradation policy, States and /
Tribes are provided with considerable
latitude in defining the requirements
necessary to protect and maintain water
quality in HQWs. EPA is proposing, for
reasons discussed iri,section C.2 of the •
preamble, that to protect and maintain
high quality water m the Great Lakes •
System, it is necessary to restrict the "•'"
significant lowering of water quality.
Significant lowering of water quality in
HQWs can only occur if ,an ' ,
antidegradation demonstration
adequately justifies the significant .
lowering of water quality and the
Director approves such lowering. For
the BCCs, in the Great Lakes context,.
EPA is proposing that any action that
results in .an increase iri the rate of mass
loading of a BCC to a HQW significantly
lowers water quality. To prevent
significant lowering of water quality
from occurring as a result of such
actions, the proposed Guidance requires
thatEEQbe maintained (e.g., that there
be rio increase in the rate of mass
loading) until an antidegradation
demonstration is" performed and an
increase approved by the regulatory
authority. ' , ; ". <- '
In addition, as regards point sources!
when the Great Lakes States and Tribes
adopt antidegradation policies
consistent with this proposed Guidance,
as is required by the CPA, the policies
will become the State arid Tribal water
quality standards or other requirements
established pursuant to State law or
regulation that are referenced in section
301(b)(lXC). At that time, when the /
discharge of BGCs is from a point source
subject to an NPDES permit, that permit
must contain EEQ limitations or
conditions, pursuant to section
301(b)(l)(C), to meet the requirements of
the antidegradation policy.
g. Ability to Accommodate a Return to
Increased Production Levels Under ,.
Antidegradation. The degree of
flexibility that a regulatory authority-has
under the proposed antidegradation
guidance to allow a return to a previous
high production level (for example;
through the resumption of a second
shift) depends on when the previous
high production level'occurred.
Consider the following scenarios:
. Scenario 1: Permit issued with facility at
production rate X; production is cut back
after issuance to X minus 100;-facility wants
to return to X during permit term. . , .
In this scenario) the return to the
higher production rate would not be ,
subject to an antidegradation review. On
issuance the. permitting agency would •.
have established, for all pollutants,
appropriate effluent limitations and, for
BCC pollutants, loading rate baselines
(i.e., EEQ) to reflect the production rate
X; The effluent limits and EEQ baseline
will not chang'e during the term of the
permit, even if production is reduced*
When production returns to X, the:
effluent limits and EEQ baseline
conditions would accommodate the
increase, and the event would not be
considered significant lowering of water
quality.
Scenario 2; Permit issued with facility at :
production rate X; facility wants .to increase
production to X plus 100,. a level attained
previously^ - '; •
In this scenario, the return to the
higher production rate may be subject to
antidegradation, depending on the
timing of the previous production
patterns and whether or not they are
reflected in the effluent limits and EEQ
baseline conditions established at the
time of permit reissuance. As discussed
above, information from the preceding
permit term should be used to
determine the effluent quality. The
permit writer has':the flexibility to use ;
the most representative information
from the preceding permit term in
making the determination. The permit
writer could account for an recent
. downturn in production by setting the
effluent limits and establishing'EEQ
baseline conditions to reflect conditions
prior to the downturn if information
was available to suggest that the
downturn was likely to be temporary. In
contrast, if a production decrease was in
evidence during the majority of the
previous permit term and likely to
continue.the"permit would likely
establish effluent limits and baseline
EEQ conditions at the level
representative of the downturni
In summary, working within the
underlying intent of the proposed
. antidegradation policy, there is some ,
flexibility to account for temporary, >
generally recent, downward trends in .
production and effluent loadings under .
this scenario.
EPA requests comihent on the •
operation of antidegradation as • ; '
discussed above. In particular, EPA is :
interested in comments about whether
the proposed Guidance provides
sufficient flexibility to accommodate :
economic recovery in the Great Lakes
region, while still preserving the intent
of the antidegradation policy to protect
and maintain wafer quality in the high
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fuality waters of the Great Lakes
ystam,
h, Relationship ofEEQ to
Implementation Procedure 8. During
development of the EEQ provisions in
the proposed Guidance, concerns were
expressed regarding EEQ limitations or
restrictions that reflected nondetectable
discharges. In particular, the
relationship between the EEQ
requirements of the Antidegradation
Policy and the requirements of
procedure 8 of appendix F to part 132
was questioned, and concerns raised
that the EEQ requirements would
necessitate fish bio-uptake studies
(procedure 8.F.1 of appendix F). EPA
believes that the EEQ and procedure 8
of appendix F provisions operate
independently and that fish bio-uptake
studies will not necessarily result from
the application of EEQ requirements.
Procedure 8 of appendix F requires that
permits include certain provisions if the
WQBEL for a pollutant is below the
detection level For BCCs, one of these
§ revisions is a fish bio-uptake study to
etormine if the discharge of a pollutant
Is occurring at a rate or level that results
in unacceptable accumulation in fish
tissue. The requirements of procedure 8
of appendix F, including fish bio-uptake
studies, only apply when the regulatory
agency has determined, using
procedures 3 and 5 of appendix F, that
a WQBEL for the BCC in question is
necessary.
Like the implementation procedures,
the EEQ provisions of the
Antidegradation Policy also direct that
controls be placed on the discharge of
BCCs. The regulatory agency may
choose that the controls take the form of
numeric effluent limitations, or may
choose to use other mechanisms to
maintain EEQ for the BCCs, such as
were discussed under "Options for EEQ
Controls". The basis for the EEQ
restrictions, whatever their form, is to
prevent the significant lowering of water
quality. The EEQ restrictions are not
based on implementation procedures 3
or 5 of appendix F. They do not
generally take the place of WQBELs
developed pursuant to these procedures.
Consequently, they would generally not
be subject to the fish bio-uptake study
requirements of procedure 8 of
always free to require fishbio-uptake
studies in conjunction with EEQ
requirements, but such studies are not
mandated by this proposed Guidance.
EPA is aware ofonly one
circumstance in which EEQ permit
conditions would necessarily require
the use offish bio-uptake studies, and
this would result not from the
nntidcgradation requirements, but
because the regulatory agency would
have chosen to use an EEQ limit in a"
permit in place of an otherwise
necessary WQBEL. A regulatory agency
" may choose to include numeric EEQ
effluent limitations for a BCC, which
would otherwise be required to be
limited by a WQBEL developed
pursuant to procedures 3 and 5 of
appendix F. If the EEQ limit was more
restrictive than the WQBEL and would
ensure compliance with the WQBEL,
then the agency may choose to use it in
the effluent limits table as a substitute
for the .WQBEL. Where such an
application of EEQ required a limitation
that was below the detection limit, the
regulatory agency would have to apply
procedure 8 of appendix F, including
the fish bio-uptake studies.
EPA believes that the Antidegradation
Policy and implementation procedures,
as written, lead to the above
conclusions. EPA would welcome
comments and suggestions on how to -
clarify the proposed Guidance to
remove ambiguity. EPA would also
welcome comments on whether or not
the proposed Guidance should be
changed to require fish bio-uptake
studies in conjunction with EEQ
requirements for nondetectable BCCs.
E. De Minimis Lowering of Water
Quality
1. Background
EPA and the Great Lakes States, in
prioritizing situations that would be
considered significant lowering of water
quality in HQWs, drew a distinction
between BCCs and other pollutants. As
discussed in detail above, significant
lowering of water quality for BCCs
focuses on EEQ. In contrast, for
pollutants other than BCCs ("non-
BCCs") the definitioa of significant
lowering of water quality keys off of
increases in permit limits, and allows
exemptions for de minimis increases
and increases that result in no change in
ambient concentration outside of any
applicable mixing zone.
The "de minimis test" is a series of
criteria that ensure that the lowering of
water quality does not result from a
BCC, and then assess the degree to
which water quality is lowered by a
pollutant, in comparison to the .ability of
the waterbody to assimilate the
pollutant Use of the de minimis test to
exempt an action from an
antidegradation review is a
discretionary decision of the Director.
Even when the lowering of water quality
for a particular situation '(Le., a specific
pollutant in a particular waterbody) may
be considered de minimis and therefore
not subject to antidegradation
demonstration requirement?, there may
still be constraints on relaxing the
limitation for the pollutant in question
because of the requirements of the
implementation procedures, such as
those for margins of safety.
2. Detailed Description of De Minimis
Test . .•
a. Specific Tests Included inDe
Minimis Demonstration. For substances
other than BCCs, a lowering of water
quality may be considered de minimis
i. The lowering of water quality uses
less than 10 percent of the unused
assimilative capacity; and,
ii. For pollutants included on Table 5
of proposed section 132.4, at least 10
percent of the total assimilative capacity
remains unused after the lowering of
water quality.
The ae minimis tests rely on the
concept of assimilative capacity, which
is the ability of a waterbody to receive
the discharge of pollutants and still
attain applicable water quality
standards. The total assimilative
capacity is determined as the product of
the applicable water quality criteria
times the critical low flow, or
designated mixing volume in the case of
lakes, for the waterbody in the area •
where the water quality is proposed to
be lowered, expressed as a mass loading
rate. The unused assimilative capacity is
that amount of the total assimilative ,
capacity not utilized by point source
and nonpoint source discharges,
including background. The unused
assimilative capacity is established at
the time the request to lower water
quality is considered. The total
assimilative capacity should remain
relatively constant over time, changing
only as the applicable criteria change or
the critical low flow of the receiving
water changes, for instance, due to
physical diversions or new flow data
used to calculate the critical low flow.
The unused assimilative capacity will
be redefined each time a de minimis test
is conducted and may increase or
decrease due to, for instance,
improvements in water quality, or-
increased uses of the waterbody,
respectively. EPA recognizes that some
pollutants will not be amenable to this
procedure for calculating total
assimilative capacity {e.g., pH, color, :
alkalinity, dissolved oxygen, salinity,
temperature). For such pollutants the
Director should employ other -
techniques to determine total
assimilative capacity, as appropriate.
With the first de minimis criterion
identified above, EPA and the Great
Lakes States and Tribes have established
a threshold below which the lowering of
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20903
water quality may not be considered :••
; significant enough, to warrant a
L thorough antidegradation review. It is
.proposed that a single action which • -. •
lowers water quality less than ten
percent of the total amount-that might
have been available to accommodate all
new actions'could be considered :, .
insignificant by the Director: when .
determining if that action must satisfy
; antidegradation requirements. EPA and
the Great Lakes States and Tribes
believe that the 10 percent value chosen
as the threshold represents a reasonable
balance between the need of the
regulatory agencies to limit the number
of actions involving non-BCCs that are
subjected to the detailed
antidegradation demonstration
requirements and the need to protect .
and maintain water quality. In
particular, it is believed that any
individual decision to lower water
quality for non-BCCs that is limited to
10 percent of the unused assimilative
capacity represents minimal risk to the
receiving water and its ability to support
all existing uses. The Director always
has the ability to override the results of
a de minimis test to determine, thai: an
• action must satisfy antidegradation
demonstration requirements if , '
information is available to the Director
that suggests that the lowering of water
quality should be considered
significant. Note also that each
successive lowering of water quality on
an individual waterbody segment will
have to be smaller than:the previous
lowering, in absolute terms, for it to be
considered de minimis. (For example, if
the first time that water quality on a
stream were lowered, the unused
assimilative capacity was 100 pounds
per day, the de minimis atoount would
have been up to 10 pounds per,day. •
Presuming an action went forward as de
minimis, using 9.5 pounds per da}', the
resulting unused assimilative capacity .
for that segment would be 90.5 pounds
per day. The next action would have to ;
involve an increase pf less than 9.05
pounds per day to be considered de ,
minimis,.and so on.) EPA welcomes •
comment on this'criterion and is
especially interested in examples of de
minimis thresholds that are currently,
used by States oi: Tribes-in. water quality
decision-making, and the rationale that
the State or tribe relied upon in the
choice of the threshold,
The second criterion involves
pollutants that would not be subject to
the Implementation procedures in this
proposed Guidance. (These pollutants
are listed in Table 5 of proposed section
132.4; the reader is referred to section n.
F of this preamble for a discussion of
these pollutants.) This criterion ensures
that a margin of safety (MOS) is set
aside for such pollutants so that the de
minimis lowering of water quality
cannot utilize the entire assimilative.
capacity. Under this criterion, an action
involving nbn-GLWQI pollutants may
be considered de minimis only if atleast
ten percent of the total assimilative
capacity remains unused after the action
occurs. •".'••... :
All pollutants that are covered by the
implementation procedures are subject '
to the requirements related to TMDLs,
WLAs, LAs and margins of safety
(MQSs). In particular, the MOS
requirements would set aside a portion
of what the de minimis test terms:the
unused assimilative capacity when
decisions are made regarding discharge
limitations. Actions that result in a
lowering of water quality,' the size of
which might be considered de minimis
under the antidegradation procedures,
might not be allowable under the
implementation procedures, because the
margin of safety'requirements might
preclude any increase of the discharge
mass loading rate limits. In this mannerj
for the GLWQI pollutants, the
Implementation and Antidegradation !
Procedures complement each other to
ensure that de minimis decisions would
not use up the entire unused
assimilative capacity. However, as
discussed below, under "3. Issues", EPA
has concerns regarding the effectiveness
of this procedure and is inviting
comment on an additional alternative.
b. Examples. The following examples
illustrate how the de minimis test ; •.
works: ... '
i. Example 1. In a stream tributary'to
a Great Lake, the most stringent
applicable water quality standards for
cadmium is 1.8 ug/L. The critical low
flow of the stream is the 7Q10 of 3000
cfs. The resulting total assimilative
capacity of this stream for cadmium is
, 29 pounds per day. At the time the
request is made to increase the loading
of cadmium to the stream, existing point
and nonpoint sources and background
contribute 14 pounds of cadmium per
day to the stream segment, resulting in
an unused assimilative capacity of 15
pounds per day. Provided that the
increassLsought is less than 1.5 pounds
per day, the increase may be considered
de ininimis. '
ii. Example 2. For a discharge directly
to a Great Lake, .the total assimilative
capacity is based on an allowable
dilution of 10 to one. Assuming that the
background concentration of iron was 0
ug/L, to meet a chronic water quality
standards for iron of 300 Ug/L the ••;
; effluent limit for iron would be 10 times
300 ug/L, which is 3*000 ,ug/L (or three
mg/L). For a discharge of one MGD, the
maximum allowable load is 25 pounds
per day. , ".
Analysis of available data shows that
the background concentration of iron
attributable to all point and nonpoint
sources is 100 ug/L. Therefore, the
unused assimilative capacity is 300-^-
100 or 200 ug/L, which translates to 17
poimds per day. The de minimis
amount for iron for the one MGD
discharge is 10 percent of 17 pounds per
day, or 1.7 pounds per day.
lii. Example 3. In a stream tributary to
a Great Lake, the dissolved oxygen
standard (a Table 5 "excluded"
pollutant) is four mg/L at critical flow
and temperature conditions. The
existing daily average dissolved oxygen
in the stream is six mg/L. The unused
assimilative capacity is two mg/L. The
de minimis dissolved oxygen impact is
10 percent of two mg/L or 0.2 mg/L. An
assimilative capacity analysis of the
tributary in question would be
conducted to identify the biological
oxygen demand (BODs) load that would
achieve four mg/L, six mg/L, and the
load increment that is equivalent to 0.2
mg/L of dissolved oxygen impact. A
BODs loading increase that corresponds
to 0.2 mg/L dissolved oxygen impact
could be considered de minimis, ,,t
because 10 percent of the total
assimilative capacity remains, unused.
In contrast, if the existing dissolved
.oxygen was 4.4 mg/L, then no increase
in BOD'could be de minimis because
more than 90 percent of the total '• /
assimilative capacity would be utilized
after the increase, i.e., the resulting
dissolved oxygen would go below 4.4
mg/L. ' '..:-.'•
3. Issues , '
During the GLWQI Technical Work
Group discussions regarding the use of
a de minimis test and the criteria that
should define it, numerous issues were
deliberated; and several alternatives
considered. In addition to comments on
the ,de minimis test laid out in the
proposed Guidance, EPA Solicits
comments on the issues and decisions
discussed below. Also, as discussed
above, under G.2 "Significant Lowering
of Water Quality", EPA is inviting -
comment on whether the use of the de
minimis test should be extended to
BGCs. EPA is interested in suggestions
regarding any changes that should be
made to the de minimis tests to address
BCCs if such a change were made to the
proposed Guidance. . ' -
a. Use of Assimilative Capacity in De
Minimis Decision, EPA notes that the
assimilative capacity described above is
functionally the same as the loading
capacity that is defined in the Federal '
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regulations at 40 CFR 130.2(f) and
which forms the basis for total
maximum daily load (TMDL)
calculations. TMDLs are discussed in
the implementation procedures section
of this preamble. The technical analysis
used to derive a TMDL may employ
moro sophisticated modelling
techniques, but is intended to
accomplish the same end as the
determination of the assimilative
capacity. EPA and the Great Lakes
States decided to use the assimilative
capacity instead of TMDL in the
definition of a de minimis increase
because of concerns regarding the
regulatory approval requirements
associated with formal TMDLs. TMDLs,
Including the derivation of the actual
TMDL number and the decisions
regarding allocation between point and
nonpoint sources and margins of safety,
receive formal EPA review and approval
as part of the water quality management
process. The State representatives on
the Initiative Steering Committee were
concerned that should the term TMDL
be used in tha de minimis definition,
their ability to make decisions on
potentially de minimis requests to lower
water quality woold be significantly
delayed and diminished, but the basis
for the de minimis decision would not
be improved. In addition, TMDLs might
not be conducted on the water bodies
that might be subject to requests for
lowering of water quality, since TMDLs
are required only for the water quality
limited segments identified by the
States pursuant to 40 CFR 130.7(b), and
water quality limited segments are
prohibited from any degradation by the
pollutant of concern under the proposed
antidagradation standards. EPA requests
comment on the proposed approach and
the considerations discussed above.
b. Fixing Assimilative Capacity at a
Date Certain and Choice of Date, The de
minimis test in the proposed Guidance
requires that the total assimilative
capacity and the unused assimilative
capacity be determined at the time the
request to lower water quality is
considered. The total assimilative
capacity should remain relatively
constant over time, changing only as the
applicable criteria change or the critical
low flow of the receiving water changes,
for instance due to physical diversions
or new flow data used to calculate the
critical low flow. The unused
assimilative capacity will be redefined
each time a de minimis test is
conducted and may increase or decrease
duo to, for instance, improvements in
water quality, or increased uses of the
waterbody, respectively.
EPA and the Great Lakes States chose
the proposed de minimis procedure
after consideration of a number of
alternatives. One alternative considered
would have required the States to
determine the total assimilative capacity
and the unused assimilative capacity on
the date that the State antidegradation
policy, as revised pursuant to the
proposed Guidance and formally
adopted into State standards, became
effective. This approach would have
required that States "fix" the
assimilative capacity numbers in all
Great Lakes System waterbodies in the
State on a specific date, and all future -
requests to lower water quality would
be considered against these numbers. As
with the proposed approach, an action
could be considered de minimis if it
used less than 10 percent of that original
, unused assimilative capacity. In
addition, at least 50 percent of the
original unused assimilative capacity
was required to remain after the
lowering of water quality for the
lowering to be considered de minimis.
Several concerns with this alternative
led EPA not to propose if First, there ,
was concern that it would be logistically
impossible for a State or Tribe to
determine the unused assimilative'
capacity numbers for all applicable
pollutants in all the Great Lakes System
waterbodies on a single date. In
addition, there were concerns expressed
about the tracking required to determine
when the cumulative effect of all actions
that lowered water quality approached
50 percent of the initial unused
assimilative capacity. Coupled with the
questionable feasibility of this approach
was the sense of the Work Group
members that establishing the unused
assimilative capacity at a date certain
and then measuring all future changes
against that figure would not accurately
assess the significance of any given
future action. Changes in the water
quality that had occurred since the
unused assimilative capacity was
determined might not be reflected in the
de minimis decision. In particular,
improvements in the water quality,
which might have led to larger mass
load increases qualifying as de minimis,
would not have played a role in this
approach.
A second alternative considered by
the Technical Work Group would have
allowed the unused assimilative
capacity to be established on the date of
the first request to lower water quality
on the segment of the waterbody
affected. This alternative was intended
to address the concern expressed about
the first alternative regarding the
feasibility of establishing the unused
assimilative capacity for all non-BCC
pollutants on all Great Lakes System
waterbodies at the same time. Under the
second, alternative approach, the unused
assimilative capacity for a particular
waterbody would not be defined until
an action was considered that might
lower water quality.-This would spread
this workload out over a far greater time
period than the first alternative, and
perhaps eliminate the need altogether
for such an evaluation of some
waterbodies. An additional benefit that
the Work Group perceived was that the
amount and quaflty of the data used to
define the unused assimilative capacity
would likely be improved under the
second alternative, as compared to the
first. Nonetheless, the other
disadvantages of the first alternative
were not improved by the second. EPA'
requests comment on the proposed '
approach and the alternatives
considered by the Work Group, and
welcomes suggestions on other possible
alternatives. .
c. Demonstration That No Ambient
Change Occurs as a Result of Increased
Loading. Although not a part of the de
minimis test, per se, the definition of
significant lowering of water quality.
allows the Director to eliminate certain
point and nonpoint actions that might
involve increased mass loadings of non-
BCCs from the antidegradation
requirements where it is demonstrated
to the satisfaction of the Director that
the ambient cTShcentration ,of the
pollutant in the affected water body,
-outside of any applicable designated
point source mixing zone, will not
increase. The provisions further state
that the Director may also take into
consideration potential impacts on
sediments and biota in the affected
waterbody in reaching the decision.
EPA and the Great Lakes States
decided to give the Director a , , *
mechanism, separate from the de
minimis test, to exclude actions that
would require an increased mass
loading rate limit, but would not
significantly lower water quality. For
instance, a point source, which draws
ground water as its process water
supply, might consider a production
increase that will require that it double
its discharge flow rate, and, therefore,
seek a doubling of the mass loading rate
limit in its permit. The discharger might
seek to prove that water quality is not
significantly lowered by providing
information for the pollutants involved
regarding the projected concentration in
the receiving water after allowable
mixing. The Director might also request
information on any potential effects on
the sediments and biota,.including those
within the mixing zone where
particulates might rapidly settle out of
the discharge into the sediments. If tha
Director concludes, based on the
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20905
analysis of this and any/ other available
information, that the increase in the
mass loading rate limit on a non-BCG
would not result in an increase in the
ambient concentration Of the pollutant*
then the action may ba considered not
to significantly lower water quality.
" "EPA believes that by providing for
such a demonstration, the number of
antidegradation reviews, and the ;
associated costs to the regulatory agency
and the regulated public, will be,
reduced. More importantly. EPA does
not believe that the environment will be
adversely affected as a result of the
. proposed demonstration, because it
does not apply to BCCs and it allows the
Director to evaluate the potential points
of accumulation of persistent substances
" when, deciding if the action will have -
adverse effects. EPA is concerned that"
any increase in the rate of mass loading
of a BCC has the potential to •
significantly lower water quality, „
because such substances accumulate in
> the biota, do not readily degrade, and .
often result in adverse effects at
concentrations well below those that
can be accurately measured in the ,
ambient environment. In contrast,
however, many of the other pollutants
do not persist or bioaccumulate
significantly. For these substances it
may not be essential that an increase in
the rate of mass loading be prevented in
order for water quality to be maintained
and protected. The demonstration
provides information to the Director to
make a decision on whether an increase
in a mass loading limit for a substance
other than a BCC changes the ambient
water quality, and highlights areas such
as sediment contamination that could
reflect degradation and, depending on
the chemical, should receive special
attention.
EPA invites comment on this
„ proposed provision and welcomes
suggestions about how it might be _'
improved. As discussed above, Yindee
C.2 "Significant Lowering of Water
Quality", EPA is also inviting comment
, on whether the use of the de minimis
test and the demonstration of no
ambient change should be extended to .
BCCs. EPA is interested in suggestions
regarding any changes that should be
made to the demonstration of no
ambient change to address BCCs if such
a change were made to the proposed
Guidance. .
Proposed procedure 5 of appendix F
whether water quality-based effluent
sections VHI.E and F of this preamble).
The decision about whether or not
limits are to be required in a permit is
different than- the.; decision, discussed
above, regarding whether or not a
proposed increase in a limit results in
the significant lowering of water quality.
EPA believes that the latter decision has
no bearing on the former and that this •
element of the proposed Great Lakes
Antidegradation Policy should-not be
used in a determination pursuant to
proposed procedure 5 of appendix F,
d. Use of the Margin of Safety
Specified in the Implementation
Procedures as a Ceiling on De Minimis
Decisions. For non-BCC pollutants on
the GLWQI list of pollutants (i.e., those
for which the implementation
procedures are applicable), the
proposed de minimis test relies on tie ,
implementation procedures margin of
safety (MOS) provisions to prevent the
allocation of virtually the entire unused
assimilative capacity to any source or
sources. The de minimis test only looks
at the relative magnitude of the lowering
of water quality resulting from any
individual action in comparison to the
unused assimilative capacity for the
pollutant in question. Provided that the
action uses no more than 10 percent of
the unused assimilative capacity, it may
be considered de minimis.
The MOS requirements provide an
additional measure of safety to the
process. The implementation
procedures require that a portion-of the
TMDL (which is equivalent to the "•
assimilative capacity) be set aside as a
MOS and not allocated to any source.
Although an action might be judged de
minimis and exempted from the r
antidegradatiottdemonstration' ..
requirements, the actual decision by the
regulatory agency on the appropriate
discharge limits, would be made
pursuant to the implementation
procedures. An increase in the limits
would only be allowed if an adequate
MOS remained after the increase in the
waste load allocation or load allocation;
and associated limits. , .'..'; '....'.
EPA considered building such: a MOS
provision directly into the de minimis
decision, as it has for pollutants not
covered by the implementation
procedures. Specifically, one option.
considered for the de minimis
procedure had included a,requirement
•that'at least 50 percent of the initial
unused assimilative capacity remain
after the lowering of water quality (in
addition to the existing. 10 percent
increment requirement) for an action to
be considered de minimis. This option
was rejected by the Technical Woik •
Group because it was considered
redundant with the implementation
procedures'MOS requirement. .-,
.Additionally, the decision not to fix the
unused assimilative capacity oh a date
certain (see discussion of previous
issue) made the use of a 50 percent cap,
as specified above, impracticable,
EPA has concerns about the reliance
on the MOS requirements* which merit
special attention and public comment.
EPA is committed to the type of a cap
that the MOS requirement in the .
antidegradation context would appear to
provide, but is concerned that the MOS
implementation procedure will provide
limited coverage. In particular,.the MOS
implementation procedure is; a part of
the larger TMDL process. As described
above under the first issue, "Use of
Assimilative Capacity hi Da Minimis __.
Decision," TMDLs are only required on
a limited number of waterbodies, for a
limited number of pollutants, and the
particular conditions that would '.'.'"
mandate a TMDL (i.e., a water quality
limited segment) might eliminate the
potential to allow any lowering of water
quality. In essence, there is a good
likelihood that the waterbodies with
TMDLs. will be the waterbodies for
which a de minimis lowering of Water
quality is not available, and vice versa,
the waterbodies for which de minimis is
a meaningful test will not require
TMDLs.
Where an MOS is defined, EPA
requests, comment on whether it
establishes the cap at a level appropriate
for a de minimis test. As discussed
above, EPA and the Great Lakes States
had considered a cap of 50 percent of .
the initial unused assimilative capacity
as reasonable in the context of a da
minimis decision. One TMDL/MOS
alternative currently under
consideration would establish the MOS
at 25 or 75 percent of the TMDL, within
the range considered acceptable for the
de minimis test,- and probably more
protective than .the figure of 50 percent
of .the unused assimilative capacity.
However, another TMDL alternative in
the proposed Guidance would allow the
MOS to be virtually eliminated if the
data supporting the TMDL are
considered to be complete. EPA is
concerned that the second alternative
would not provide a reliable protective
cap for the de minimis procedure.
• EPA requests comment on these two
, issues regarding the use of the
implementation procedures'MOS
requirement, and, in particular, seeks
advice on the need to directly
incorporate a. cap into the de minimis
test rather than rely on an. external
process that may not always be
available. ~
e. Multiple De Minimis Lowering of
Water Quality by a Single Source. The
de minimis test ini the proposed
Guidance1 does not restrict the number
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of times that any individual source
could seek an increase in permit limits
for a non-BCC, and have that increase
considered de minimis. The proposed
Guidance simply looks at the effect of
individual actions, not the source
involved.
This has led to a concern that under
the test, dischargers would try to get
piecemeal approval of large projects by
submitting multiple requests to lower
water quality, each of which could be
considered de minimis, but the net
effect of which would be significant
lowering of water quality. EPA believes
that the procedure provides the Director
with the discretion to prevent such
abuse, but is nonetheless concerned that
there could bo considerable pressure
brought on the Director to allow relief
in individual cases.
EPA solicits comments on this
concern. In particular, EPA is interested
in whether cornmenters believe that it
would be appropriate to limit the
number of de minimis actions allowed
any individual source to one (or some
other number).
EPA also solicits comment on an
approach that would address multiple
lowering of water quality by different
sources where the net effect is greater
than 10 percent of the unused
assimilative capacity. The approach
proposed in this policy would
potentially allow any individual action
that uses less than 10 percent of the
unused assimilative capacity to be
considered de minimis, provided that
tho MOS requirement of the
implementation procedures or the
requirement in the definition of de
mlnimls in section II.A of appendix E of
tho Great Lakes antidegradation policy
was satisfied. During Work Group
deliberations, EPA considered an
alternate approach that would have
assessed the cumulative effect of
sequential actions when determining if
the lowering of %vater quality used less
than 10 percent of the unused
assimilative capacity. For example,
under such an approach, an action that
utilized six percent of the unused
assimilative capacity might be
considered de minimis, while a
subsequent action that utilized five
percent of the unused assimilative
capacity could not be considered de
minimis, because the net effect of the
two actions was greater than 10 percent
of the unused assimilative capacity. The
second action would be forced to go
through a complete antidegradation
raview. However, subsequent actions
would bo evaluated against the unused
assimilative capacity that would exist
after the Director's antidegradation
decision was implemented, with the
potential for future de minimis lowering
of water quality until such time as the
next 10 percent increment was utilized.
EPA is not proposing this approach '
because of concerns regarding its
implementation. EPA believes that the
proposed de minimis requirements
provide adequate protection of water
quality. Further, the implementation of
an approach such as that described
above may place inequitable burdens on
entities that propose to lower water
quality, based not on the extent of
degradation posed by any individual
action, but rather as a result of the
position in which it falls in a sequence
of decisions. EPA believes that the
assessment of multiple lowering of
water quality is best addressed with the
proposed MOS requirements and the
proposed de minimis requirements of
section II.A of appendix E of the
proposed Guidance. The intent of these
provisions hi the proposed approach is
to capture the effect of multiple actions
by establishing a single point beyond
which no individual action could be
considered de minimis. EPA welcomes
comment on this alternative approach to
addressing multiple lowering of water
quality, as well as the concerns noted
above.
F. Antidegradation Demonstration
Components
1. Background and Rationale
Both the Federal antidegradation
policy and the antidegradation policy
proposed in the proposed Guidance
provide the regulatory, agency with the
opportunity to allow the lowering of
water quality in HQWs, if it is found
that "the lowering of water quality is
necessary to accommodate important
social and economic development in the
area in which the waters are located."
To date, EPA has provided little formal
guidance on what it considers the
specific tests that should be used or
criteria that should be satisfied to
demonstrate that a lowering of water
quality meets this requirement. The
proposed Great Lakes Guidance tries to
Strike a balance between the need to
protect and maintain high quality water
and the need to accommodate growth.
The existing National policy requires
this balance to be struck and the. .
decision to be a public one. The tests
established by the proposed Guidance
are intended to be reasonable tools to
accomplish that balance. EPA invites
comments and suggestions on all
aspects of the antidegradation
demonstration and decision parts of the
proposed Guidance to ensure they are
reasonable.
As discussed during GLWQI
Technical Work Group meetings, this
part of the antidegradation policy, in
particular, is viewed by the Great Lakes
States and the regulated community as
having a very high potential to lead to
inconsistent decision-making between-
and even within States" and Tribes. Two
of the primary objectives of EPA and the
Steering Committee in developing this
antidegradation guidance were to
provide an explicit description of the
meaning of this requirement and an
increased level of specificity regarding
the appropriate tests and , ' ' , .
demonstrations to make such a showing.
The Great Lakes Antidegradation
Guidance, in defining the
demonstrations required to show that a
lowering of water quality should be • •
allowed, begins with a literal
interpretation of the National regulation.
That is, it interprets the phrase, "the
lowering of water quality is necessary to
accommodate important social and
economic development in the area in
which the water's are located" to mean
that two types of demonstrations are
required: one that shows that the
lowering of water quality is necessary,
or cannot be avoided, to support the
development; and a second that shows
that the development is important, EPA
specifically invites comment on this
interpretation of the existing National
regulation. The two types of
demonstrations are defined under the
Antidegradation Demonstration heading
in the proposed Guidance (section III of
appendix E to part 132), and the
requirements for the incorporation of
the results of the demonstrations into
water quality decisions are'found under
the heading Antidegradation Decision
(section IV of appendix E to part 132).
The Antidegradation Demonstration
section of the proposed Guidance ..
identifies two broad categories that will
be required of an entity to make the
"necessary" component'of the
demonstration; information to show
how prudent and feasible pollution
prevention alternatives might be
implemented to eliminate or reduce the
extent to which watervquality is
significantly lowered (section III.A of
appendix E to part 132); and
information to show what alternative or
enhanced treatment exists that would
eliminate the significant lowering of
water quality and what it costs in
.comparison to the cost of "normal"
pollution control (section IILB of
appendix E to part 132). Each of these
is discussed in detail below.
The Antidegradation Demonstration '
section also identifies information that
will be required of an entity that is
seeking to significantly lower water
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quality in order to show that the
lowering supports "important social or
economic development'* (section HI.D of
appendix E of the proposed Guidance).
- Five broad categories of social or
economic developments, which are '
considered important, are identified.
This demonstration, too, is described in
detail below and under a separate
- subsequent heading in this preamble.
• 2. Hierarchy of Antidegradation
Demonstrations '"•'.''-'-.
A hierarchy is established for the
demonstrations in. the proposed
Guidance that is not only a logical
sequence but also reflects a priority of
EPA. As laid out in the proposed
Guidance,, the first tier in the hierarchy
is. the pollution prevention alternatives
analysis: successful implementation of
such alternatives to eliminate the
, significant lowering of water quality
,relieyes the entity of the requirement to
i supply additional information regarding
alternative or enhanced treatinenl and
the social or economic development
p'rovided by the action. EPA believes it
is appropriate to require that art entity
provide information that the Director
.will use to determine if the lowering of
water quality is necessary,. i.e., cannot
be prevented while still accommodating
" the action, before it is required to
demonstrate that the action is an . -
, important social or economic
development or is critical to ths support
of such development. Furthermore, EPA
and the Great Lakes Steering Committee
place a very high priority on the
application of pollution prevention
. techniques as. the preferred approach to
;%prevent or reduce the significant
lowering of water quality. Consequently,
the first demonstration evaluates the
extent to which prudent and feasible
pollution prevention alternatives reduce
or eliminate the significant lowering of
water quality that would otherwise
accompany the development, la •
assessing prudent and feasible ,
" alternatives, EPA believes that it will be
appropriate to compare the unit cost
(dollars per toxic pound equivalent) of
removing a pollutant or type of
•pollutant using the pollution prevention
alternatives under consideration with.
benchmark controlestimates. As a
benchmark for such a comparison, EPA
is considering the unit cost estimates
($1.30 to $10.40 per toxic pound
equivalent) developed for source
categories as a part of this rulemaking
or, alternatively, the incremental cost
estimates developed as a part of EPA *s
'effluent guidelines for source categories
($1 to $500 per toxic pound equivalent).
Thd details of this demonstration are '
discussed under section F.3 of this
preamble.
The proposed Guidance directs the
regulatory agency to require the
implementation of prudent and feasible
pollution prevention alternatives as a
precondition to the lowering of water
quality. If the implementation of such
alternatives would eliminate the need to
significantly lower water quality, no
further: demonstrations are required, the
. facility may proceed (with the pollution
prevention measures in place), and
appropriate control requirements are
established in the control document to
ensure that water quality is not ----._
significantly lowered. If prudent and
feasible pollution prevention
alternatives do not eliminate the
lowering of water quality, but do reduce
the extent to which the water quality is
significantly lowered,, the Director will
establish conditions in the control
document that, at a minimum, ensure
• that water quality is not lowered any
more than it would be if the prudent
and feasible pollution prevention
alternatives were implemented, and
which may be more stringent depending
on the results of the other evaluations in
this section. .
The second tier in the hierarchy
requires the evaluation of alternative or
enhanced treatment techniques to.
determine the cost to the entity of ,.
providing additional or different
treatment to eliminate the significant
lowering of water quality. Again, EPA
believes it is appropriate to require that
an entity provide Information for the
Director to use to determine if the
lowering of water quality is necessary
* before it is required to provide •
information for the Director to use to
determine if the action is an important
.social or economic development or Js
critical to the support of such
development. This tier represents a
second type of ^formation that the
Director may use to determine if the
significant lowering of water quality is
necessary. This evaluation builds on the
results of the first: if prudent and
feasible pollution prevention "
alternatives could eliminate a portion of
the significant lowering of water quality,
i.e., reduce the amount by which the
rate of mass loading of a pollutant must
be increased to accommodate the action,
then the evaluation of alternative or
enhanced treatment techniques should
be applied to the remaining increase in
•loading. (As an example,, if a proposed
action initially would have required an
increase in the rate of mass loading of
a pollutant of 100 pounds per day.'and
the implementation of prudent and
feasible pollution prevention
alternatives drops that increase to 50 •
pounds, per day, then the evaluation of
alternative or enhanced treatment
should, generally, only look at the cost
of eliminating the remaining 50 pounds
per day.) The cost (capital and operation
and maintenance) of the alternative or
enhanced treatment is. compared to the
comparable cost of the treatment
required to meet technology- or water ,
' quality-based requirements or
requirements based on other State or
Federal standards and, where the ratio
is less than or equal to 1.1 to one, the
lowering of water quality is not
" considered "necessary" and there Is no
need to consider information on the
social or economic development that the
proposed significant lowering of water .
quality would have supported. Instead,
as the Antidegradation Decision .
provision of section tV.A«2 of appendix
E to part 132 requires, the significant .
lowering of water quality is not aHowed,-
and.either the permitted discharge
levels remain unchanged or the
.appropriate control requirements are
established in the control document to
ensure that water quality is not
Significantly lowered. As an alternative,
EPA is requesting comments on a cost
effectiveness approach using a
comparison of the control costs (per
toxic pound equivalent) of the enhanced
treatment .with baseline control costs
(per toxic pound equivalent). When
control costs for the enhanced treatment
are no greater than the baseline costs,
facilities would be expected to adopt the
enhanced treatment techniques.The
details of the second demonstration ara
discussed in section F.4 of this ,
preamble.
There may be occasions-when it is
more cost effective to simply provide
alternative or enhanced treatment to
eliminate the significant lowering of
water quality, rather than to couple such
treatment witii pollution prevention
techniques, and a discharger may ;
propose feat treatment alone be used to
eliminate the> significant lowering of
water quality. In reaching such a
decision, EPA anticipates that the .
discharger would have evaluated the
benefits of the available pollution
prevention alternative, such as the
reduction in cross-media pollutant
transfers and any associated regulation
under other environmental statutes.
This proposed Guidance provides the
flexibility for the Director to
accommodate those situations* with the.
objective of finding the most
appropriate means of eliminating the
significant lowering of water quality,
where possible. EPA, however, believes
that in the majority of situations, the
prudent and feasible pollution
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20908 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
prevention alternatives will
complement the alternative or enhanced
treatment techniques, and that the most
effective mechanism to prevent the
significant lowering of water quality
wul be a combination of the two.
Tho third tier of the hierarchy is the
demonstration that the significant
lowering of water quality is critical to
important social and economic
development. To have reached this
point in the process, the Director would
have been given information on the
ability of the entity to prevent the
significant lowering of water quality and
that information would have shown that
the significant lowering of water quality
could not be prevented by the
application of prudent and feasible
pollution prevention alternatives in
combination with alternative or
enhanced treatment that is available
Within a defined cost range. The
proposed Guidance requires the entity
to demonstrate how a decision not to
allow the significant lowering of water
quality, i.e., disapproval of the proposed
significant lowering of water quality,
will prevent important social or
nconomic development in the area in
which the waters are located. The
proposed Guidance lays out five broad
areas of social or economic
development, which would be
considered "important". These are
discussed in detail in section F.5 of this
preamble. If the significant lowering of
water quality is critical to a
development in any one of these areas,
the Director may tentatively approve it,
subject to public comment and
intergovernmental coordination,
3. Identification of Prudent and Feasible
Pollution Prevention Alternatives TO
Prevent or Reduce the Significant
Lowering of Water Quality
The pollution prevention alternatives
analysis section of the proposed
Guidance, section m.A of appendix E to
part 132, identifies five categories of
alternatives that must be evaluated by
an entity seeking to significantly lower
water quality. They are as follows:
a. Substitution ofBCCs ivith Non-
bioaccumulative and/or Non-toxic
Substances. The primary objective of
this evaluation is to determine if the
source of a BCC, which would otherwise
be causing or contributing to a
significant lowering of water quality,
can be eliminated in favor of a less
environmentally problematic substance,
for example a substance that is not a
BCO
b. Application of Water Conservation
Methods. This evaluation considers
whether the introduction of water
conservation methods by a discharger is
feasible and, if so, whether their
.implementation would prevent or
reduce the significant lowering of water
quality;
c. Waste Source Reductions Within
Process Streams. Certain production
processes may have the potential to be
"fine-tuned", but have not been because
of a lack of any compelling reason to
attempt to do so in the past. This
evaluation would look at the potential
for such fine tuning to relieve the need
to significantly lower water quality;
d. Recycle/Reuse of Waste
Byproducts, Either Liquid, Solid, or
Gaseous. Internal recycling/reuse of
waste streams is a common practice in •
many industrial and manufacturing
processes to hold down energy, raw
materials, and waste disposal costs. This
evaluation would consider whether-
additional or new recycling/reuse
operations are available that would
relieve the need to significantly lower
water quality; and
e. Manufacturing Process Operational
Changes. This evaluation would '
consider the alternatives to a particular
industrial or manufacturing process that
are available to the entity that seeks to
significantly lower water quality. For
many operations, a variety of processes
exist to reach the same end product, or
one that is within set tolerance limits.
The specific operation should be
evaluated and any available, acceptable
alternatives that would relieve the
significant lowering of water quality
identified.
The categories of pollution prevention
information identified in the proposed
Guidance are intended to be interpreted
broadly so as to provide for
consideration of a wide range of
possible alternatives. Furthermore, it
may well be appropriate for the Director
to consider a combination of
alternatives from several categories
operating in conjunction. The categories
provide a guideline on the minimum
coverage of a pollution prevention
evaluation for entities that seek
authorization to significantly lower
water quality. In addition, nothing in
this demonstration requirement bars the
Director from requestingjjollution
prevention alternatives information as
the Director might deem necessary to
evaluate the request to significantly
lower water quality. The authorities to
request the pollution prevention
information outlined in the proposed
Guidance, and any additional •
information the Director deems
necessary to make the evaluation, derive
from the same statutory provisions as
other information requests under the
NPDES and nonpoint source programs.
An entity that is pursuing authorization
to significantly lower water quality
should consult with the appropriate
regulatory authority to determine the
specific alternatives that it will be
expected to evaluate.
The following provides brief
examples of alternatives that would be
appropriate for consideration in the
context of, first, an industrial point
source and, second, a municipality,
using the category "substitution of BCCs
with non-bioaccumulative and/or non-
toxic substances". Depending on the
• context, BCCs may be used as, or
present in, raw materials in production
processes, in consumer products, and in
a variety of other ways.
The scope of alternatives evaluated
will vary according to the source. For
example, a coal fired power plant
seeking to increase its generating
capacity might be faced with the
prospect of a larger coal pile and an
increased amount of mercury
contaminated runoff. The alternatives
that should be evaluated in such a
situation, to reduce the loading of
mercury from coal pile runoff, would
include use of an alternative supply of
coal containing less mercury as a trace
contaminant. The substitution of a
"cleaner" coal supply would have the
added benefit of reducing air emissions
of mercury, which would also help to
maintain and protect water quality. The
information provided by the power •
plant would include the effectiveness of
the alternative source with regard to
reduction in the rate of mass loading of
mercury, differential (greater or lesser)
cost associated with the new coal •
source, impediments to using the
alternate coal or its source (supplier),
and other environmental effects
(positive or negative), as the Director
deems necessary to determine if the
alternative is prudent and feasible.
As another example, a municipality, .
which has a mercury mass loading limit
in its NPDES permit, that is considering
expansion of the sewer service area, and
requests a corresponding increase in the,
wastewater flow and mass loading
limitations, would have a number of
potential alternatives to limit the source
of mercury discharges to its sewers. A
ban on the introduction of mercury into
the sewer system, coupled with a strong
public education program emphasizing
the problems with, for example, broken ,
mercury thermometers, the contents of
which are flushed down the toilet, or •
mercury-containing exterior latex paint
cleanup in the kitchen sink, might be a
particularly viable alternative. The
municipality should also consider the -
effectiveness of workingjback to its ~
industrial users,to identify arid
eliminate mercury sources using jts
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sewer use ordinance arid inspections to
ensure compliance. .The same type of
. information as was Discussed in tlie
power plant example above would be
provided to assist the Director in
determining if such alternatives are
prudent and feasible.
The proposed Guidance does not.
specify criteria to be used by the '.
Director,to determine.what is "prudent
and feasible." The decision that an
alternative or combination of
alternatives is prudent and feasible is
the decision of the Director, and not the
entity that is seeking to significantly
lower water quality. States and Tribes
are encouraged to develop their own
guidelines to follow when evaluating
pollution prevention alternatives
identified by the entity to select those
that are prudent and feasible. EPA
believes that in •making this
determination it will be appropriate to
compare the control costs implicit to the
. pollution prevention alternative with.
benchmark control costs. EPA requests
comments on the merits of this
approach and suggested alternatives that
might be used to inform this decision.
Concerns were expressed during
deliberations on the proposed Guidance
that the determination of what
constitutes prudent and feasible .
pollution prevention alternatives could
involve multiple iterations of
demonstrations by the regulated entity.
1 In particular, there was a concern that
the proposed Guidance does not itself
specify the information needs for a
satisfactory demonstration nor does it
require that the needs be articulated
definitively by the regulatory agency at
the outset Furthermore, the proposed
Guidance does not place constraints on
the regulatory agency's ability to require
multiple demonstrations by an entity
until it provides information that the
. Director considers satisfactory. EPA
' acknowledges that the language in the
proposed Guidance does not provide
specific guidance on how the Director :
makes a determination of what is '•.:
prudent and feasible. EPA requests •.-.
comment on the heed for establishing
more specific criteria for this
• determination.
EPA expects that in implementing the
prudent and feasible qriterion the •
regulatory agency and that the
regulatory agency will not abuse the
criterion to simply delay .projects
, through multiple iterations of
information requests. As discussed
above, EPA anticipates that the States
will develop guidance to assist in this. -
.case-by-case decasioii'making..
. Nonetheless, EPA .recognizes that there
may be instances in which the.,.
; regulatory agency requires additional
information, beyond that anticipated in
an initial request, to make a decision on ;
prudent and feasible pollution
prevention techniques. While the
regulatory agency should seek to
develop guidance to limit such
instances, it should not be coihpelled to
make decisions on an inadequate .-.'.-•
demonstration. -
EPA specifically requests comment on
the use of "prudent and feasible" as the
criterion upon which pollution
prevention alternatives are evaluated
and chosen by the Director. EPA is „ -
interested in whether the proposed
Guidance provides the correct level of
detail to assist in this decision, and if
not, what additional detail commenters
feel should be incorporated. While the
proposed Guidance does not explicitly
require cost/benefit or cost effectiveness
analyses, in determining what is
prudent and feasible EPA believes that
the Director will likely..weigh the cost of
the pollution prevention measures
against the benefits with regard to the
reductions in pollutant loading. EPA
requests comment about whether a
formal cost/benefit analysis or a cost
effectiveness-analysis with defined
decision criteria should be part of the
prudent and feasible decision. As
regards decision criteria for a cost
effectiveness analysis, EPA believes that
it may be appropriate to compare the
unit cost (dollars per pound equivalent)
of removing a pollutant or type of
pollutant using the pollution prevention
alternative under consideration with
unit cost estimates developed for this
rulemaking ($1.30 to $10.40 per toxic
pound equivalent) to reach a decision.
Alternatively, the incremental unit costs
associated with implementation of a
particular pollution prevention •
alternative could be compared to the
incremental costs used in EPA's effluent
guidelines for a comparable industrial
category ($1 to $500 per toxic pound
equivalent for a waste stream)..In either
case, where such a comparison showed
that a pollution prevention alternative
could remove an equivalent amount of
a pollutant or pollutants at no greater
cost, that alternative could be .
considered feasible. EPA requests
comment on these possible approaches 7
to assessing cost effectiveness. EPA
would also welcome examples of >
alternative criteria that have been :
effectively employed by commenters in
similar decision-making situations.
4. Alternative or Enhanced Treatment
Alternatives That Eliminate the ;
Significant Lowering of Water Quality
Section IH.B of appendix E of the
proposed Guidance requires that an
entity seeking to significantly lower
water quality (and not able to identify ,
prudent and feasible pollution
prevention alternatives that eliminate
the need to significantly, lower water j
quality) provide information on the
alternative Or enhanced treatment
techniques that could be utilized to treat
its waste stream and that eliminate the
need to significantly lower water •
quality. Put another way, the entity has;
to tell the Director what it. would cost
for treatment to maintain the status quo .
in terms of effluent quality for BCCs and
effluent limits for other pollutants, and
what that treatment would entail. In "
addition to the information on
alternative or enhanced treatment, the
"entity must provide comparable
information on the treatment that would
be required to comply with the revised
effluent limits that it is seeking. These
revised limits would be defined by the
applicable Federal effluent guidelines,
.State water quality standards (other than
antidegradation), and other applicable
State or Federal standards.
The cost information provided for this
demonstration will include both total
capital costs of treatment facilities and
the operation and maintenance Costs ."~
associated with running them. Cost
information must be providedjor the
least costly alternative that eliminates
the significant lowering of water quality.
Cost information must also be provided
for the treatment system: that would be
required to meet the revised (increased)
limits. The costs information developed
for the two scenarios must be
comparable. That is, the assumptions
used in one scenario (e.g., depreciation
factor, useful life, constant dollars) niust
be consistent with those used in the
other. Furthermore, the capital cost '
information should incorporate the
capital cost of the existing treatment
facility if it will be utilized in the
treatment train to meet the revised
limits or to eliminate the need to '
significantly lower water quality,.rather
than only the incremental costs of
i additional treatment, or alternative or
enhanced treatment In addition, the
costs of the prudent and feasible
pollution prevention techniques are not
included in the costs of alternative, or
enhanced treatment, but rather factor '
into the base costs against which the
cost of alternative or enhanced . ..
treatment is. compared.
EPA requests comment on the
benchmark costs used in the proposed
analysis. In the approach described
above, the entire capital expenditures
over the life of a facility would be used.
This could be argued to have the effect
of "punishing" an entity, that had spent
large amounts on a treatment system,,in
, the past EPA is particularly interested
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in whether commenters believe that it is
more appropriate to use only a portion
of the total capital costs of a treatment
system {e.g., the capital expenditures
•'•juring the last permit term, or the
jepital expenditures that will be
necessary to comply with any new
limits that will derive from other parts
of the proposed Guidance) in such an
analysis.
The proposed Guidance requires that
the total costs to eliminate the
significant lowering of water quality be
compared to the total costs to comply
with the requested revised permit
limits, If the ratio of the costs is less
than or equal to 1.1 to one, i.e., if up to
a 10 percent increase in the cost of
treatment over what will otherwise be
required will eliminate the significant
lowering of water quality, then the
.entity will be expected to utilize the
additional treatment to prevent the
significant lowering of water quality.
The control document issued to the
entity will not allow an increase of mass
loading limits, or in the rate of mass
loading of a BCC. In such cases, since
the action no longer necessitates the
significant lowering of water quality, the
entity no longer needs to provide
information to show that important
social or economic development is
supported. If, however, the additional
10 percent expenditure for alternative or
enhanced treatment will not eliminate
tha significant lowering of water quality,
the entity must provide social or
economic development information to
k emphasizes that the Alternative
or Enhanced Treatment test establishes
a mandatory expenditure provision
which identifies the minimum that will
bo expected of an entity seeking to
significantly lower water quality and the
condition under which it is effective.
This proposed Guidance reflects the
priority of EPA and the Steering
Committee to protect and maintain the
§uality of the water in the Great Lakes
ystem. It establishes a minimum level
of expenditures that must be made on
treatment if it prevents the significant
lowering of water quality. It does not
mean that the significant lowering of
water quality will automatically be
approved if that minimum level of
expenditure does not prevent the
tignificant lowering of water quality.
The mandatory minimum expenditure
established by this provision reflects a
policy position of EPA and the GLWQI
Steering Committee regarding the value
of maintaining and protecting water
quality in tha Great Lakes System.
Whila it reflects the value attached to
tho Great Lakes, it does not represent a
formal cost/benefit analysis by EPA or
the GLWQI Steering Committee. The
GLWQI Steering Committee was
particularly concerned that a numeric -
minimum guideline be established for
this test to promote consistent decision
making among the Great Lakes States
and Tribes. EPA requests comment on
the ratio that is proposed to establish
this minimum cost requirement,
whether it is set at the appropriate level,
and whether a single ratio should be
identified or various ratios depending
on tie entity (public or private).
Comnasaters are encouraged to provide
specific examples of alternative
provisions that EPA might consider and
are referred to another set of tests
described later in this preamble as a
possible alternative for which EPA is
also requesting comment. EPA also
solicits comment on whether the
proposed Guidance should rely on a
cost/benefit analysis to establish the
appropriate ratio, or whether the .
proposed Guidance should propose the
use of cost/benefit analyses on a case-
by-case basis to determine mandatory
expenditures on alternative or enhanced
treatment to prevent the significant
lowering of water quality.
Finally, EPA requests comment on an
alternative that would compare the
control costs (per pound of toxic
equivalents) of alternative or enhanced
treatment techniques with a benchmark
estimate of control costs—that is, '•
evaluate the cost effectiveness of these
enhanced treatment alternatives. EPA
might use as a benchmark the control
cost estimates for comparable source
categories developed under the effluent
guidelines program or the control cost
estimates EPA is developing as a part of
this rulemaking. Thus, if the cost of *
control (per pound of toxic equivalent)
for an identified enhanced treatment
technique were no more than the
benchmark control cost (per pound of
toxic equivalent), this treatment
technique would be considered to be
available and this treatment level would
be expected to be adopted as a part of
the antidegradation demonstration.
Otherwise the enhanced treatment
would be considered unavailable,
EPA considered the following text for
inclusion in the rule in place of that
currently found in the last two
sentences of proposed section in.B of
appendix E to part 132:
The evaluation shall compare the control
costs (per pound of toxic equivalent) of such
alternative or enhanced treatment with the
benchmark control cost estimates for source
categories. (See control cost estimates set out .
in Table X (table would be developed for
inclusion in rule].) If the control cost (per
pound of toxic equivalent) is no greater than
the benchmark control cost, the entity shall
not be required to provide the information
specified in section ni,D,
A similar conforming change would also
be made to section IV.A.2 of appendix
E of the proposed rule.
An important advantage of this
approach would be that it combines the
cost of the enhanced treatment
techniques with a measure of its
effectiveness. EPA believes that,,in
considering effectiveness as well as cost,
this may represent an improvement over
the proposed approach. The proposed
approach establishes an arbitrary
requirement that future costs of an •
enhanced treatment technique should
not exceed 1.1 times the past sunk cost
of existing treatment controls, and
requires the enhanced treatment only if
it is completely effective at eliminating
the increased loading of pollutants (i.e.,
100 percent effective). The 1.1 to one
ratio may be too low for very large
reductions in loadings and too high for
very small reductions in loadings.
EPA requests comments on the
alternative cost-effectiveness approach.
In particular, EPA is interested in
comments on the use of a benchmark
control cost based on1 unit cost estimates
developed for source categories as a part
of this rulemaking ($1.30 to $10.40 per
toxic pound equivalent). Alternatively,
the benchmark could be based on the
incremental cost estimates developed as
a part of EPA's effluent guidelines for .
individual source categories ($1 to $500
per toxic pound equivalent for a
wastestream). EPA also requests
comments on the appropriate ratio to
use in comparing the costs of an
enhanced treatment technique with
baseline control costs. The above
discussion assumes a ratio .of one-to-one
(i.e., the enhanced treatment cost is no
more than the baseline cost, per toxic
pound equivalent), but EPA is interested
in whether commenters feel the ratio
should be greater, for example 1.3 to
one, which would result in enhanced
treatment being required if it costs no ,
more than 1.3 times the baseline cost of
control (per pound of toxic equivalent).
This provision does not constrain the '
Director from.requiring more costly
treatment to eliminate the significant
lowering of water quality, nor does it
prevent the Director from requiring that
the alternative or enhanced treatment be,.
implemented in cases where it does not
fully eliminate the need to significantly
lower water quality. However, such "
decisions are the best professional
judgment of the Director, and are not
dictated by this proposed Guidance.
Furthermore, this provision must not
be construed to have any bearing on the
ability of EPA or the States or Tribes to
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20911
seek appropriate relief for the violation
of NPDES permit limitations or. other
enforceable requirements, up to and
including the maximum amounts
available under the applicable-statute.
This provision is relevant only in the
• permitting process for the purposes of
antidegradation decisions. It does not
apply in the compliance context. The
cost of complying with the terms and
conditions of a permit does not excuse
non-compliance. The lowering of water
quality is never allowed when it would
cause water quality standards to be
exceeded. In the enforcement context,
EPA conducts aii "ability to pay"
analysis which is a complex calculation
of the economic impact of compliance
and payment of civil penalties on lie
members of the regulated community.
"Affordability", as it might be
considered in the context of an
antidegradation decision, is not
considered in either a penalty analysis
or an ability to pay calculation. In the ,
penalty; context, aii ability to pay ,
calculation is, not a determination of
affordability; penalties are a deterrent
, and are not designed to be affordable as
a cost of doing business. Rather, in
considering ability to pay, EPA
considers a violator's inability to
continue in business after achieving
compliance and paying a civil penalty.
Compliance with the law is the .
minimum requirehient in the
enforcement context; EPA requests •
comment on whether the proposed
Guidance is sufficiently clear on these
p'pints or if additional detail is
warranted.
EPA also solicits comments on
whether the.alternative or enhanced
treatment analysis should include, in
addition to such cost considerations*
consideration of relative energy.
consumption, air emissions, and other
n on-water quality impacts. •
5. Social or Economic Development ,
Demonstration . ' •.
Section ffl.D of appendix E of the
proposed Guidance defines the
requirements for a demonstration thai
the necessary significant lowering of
water quality supports important social
or economic development in the area in
which the waters are located. To have
reached this point in the process, the
Director would have been given
information on the ability of the entity
to prevent the significant lowering of
water quality and would have
determined that information showed
that the significant lowering of water
. quality could not be prevented by the
application of prudent anil feasible :
pollution prev-'ntuHvalternativesiin
, combination wi ;b altemau ve or • ;. . T, .
enhanced treatment that is available
within a defined cost range. Then, the
social or economic development
demonstration is conducted to show
how the development is important to ,
the community in the area in which the "
waters are located in, terms of
employment, financial, or social .
services contributions.
Defining the area in which the waters
are located is a case-by-case
determination by the Director that may
consider the pollutants involved in
addition .to the location of the discharge.
The benefits of a development, which
would cause it to be considered
important in an antidegradation.
decision, should be those realized
within the area in which the waters are
located, as opposed to outside of the
' area in which the waters are located.
EPA requests comments on how broadly
the area in which the waters are located
should be defined. For example, should
the area be limited to the close
proximity of a discharge, the entire
Great Lakes System, or some
intermediate/and should the decision
depend on the type of pollutant
involved? •
The analyses used by the regulatory
agency under this provision measure the
amount of social and economic gain, or
loss prevented, in the area in which
water quality is proposed to be
significantly lowered and assess the
environmental effects due to the action
proposed. Information on the following
areas of social or economic development
resulting from the action that results in
the significant lowering of water quality',
are to be provided by the entity
proposing the actionrincrease in
number of jobs; increase in personal
income and/or wages; reduction in
unemployment rate or social service
expenses; increase in tax revenues; and
provision of necessary Social services. \
Each of these should be examined in
terms of both the absolute size arid the
relative size of the change.
In evaluating the changes in any of
these five types of factors, as well as the
environmental effects, logically three
references should be established: the
baseline situation, the net impact, and :
other possible developments.
a. Baseline Situation. Once the area
has been defined, its baseline condition ,
, should be evaluated in terms of its
unemployment rates, percentage of the
population living on incomes below the
-poverty tline, percent of population that
are elderly, and average household
Income compared to state or national
averages and any other information
requested by the Director. Additional
, jobs and/or lax revenues are particularly
important to economically-depressed :
areas. >.•'.•
b. Net Positive Impact. The net impact
is relevant in measuring the importance
of the development. It is determined by
correcting the amount of benefits to
account for any adverse impacts that'
result from the development, such as
the loss, of tourism income if the
lowering of water quality reduces the
recreational Opportunities, or the
increase hi operating costs of other
facilities that use the water and any
other information requested by the ,
Director. * •
c. Other Developments. In
determining if a particular development
is important, the Director should
consider whether other developments of
comparable contribution will, occur in
place of this particular one. -
The proposed Guidance provides no
numeric benchmarks against which
social and economic developments are
measured to determine if they are
important. Rather, provided that the
developments fall into one of the above
categories, which EPA and the Steering
Committee agree are inherent
benchmarks of importance, the final ;'.
decision on whether they justify the
significant lowering of water quality is
left to the discretion of the Director,
' taking into account the specific
characteristics of the pollutants
involved, the affected community, and
the comments of the public. It is in the
context of making this decision that the
Director may require additional controls
beyond those mandated by the pollution
prevention alternatives and alternative
or enhanced treatment analyses,, to
restrict or prevent the lowering of water
quality.
EPA encourages comment on this
element of the proposed Guidance, and, •-
in particular, on whether it provides
sufficient detail to assist the Great Lakes
States and Tribes in making consistent
decisions. '
6. Special Remedial Action Provision
Section in.E of appendix E of the
proposed Guidance provides a special
antidegradation provision for remedial ,.
actions that are not otherwise exempted
from the definition of significant ,
low.ering of water qualityv Remedial
actions subject to this provision would
include those implemented pursuant to
State or Federal authorities, such as the
Resource Conservation and Recovery
Act (RCRA) or CERCLA, with the
purpose >of cleaning up, environmental
contamination. Such actions do not lend
themselves to the evaluations discussed
above, involving alternative or ;
enhanced treatment or social or
economic development. Accordingly, >
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Federal Register / VoL 58, .No. 72 / Friday, April 16, 1993 / Proposed Rules
EPA believes that an alternative test
should be used to establish, that a
significant lowering of water quality is
necessary to accommodate important
sodal or economic development Such
an alternative is established by this
provision.
Under section HLE of appendix E of
tho proposed Guidance, entities
proposing remedial actions submit
information to the Director that
demonstrates that the action utilizes the
most cost effective pollution prevention
and treatment techniques available, and
minimizes the necessary lowering of
water quality, in lieu of the information
required by sections IH.B through D of
appendix E of the Antidegradation
Demonstration portion of the proposed
Guidance (covering alternative or
enhanced treatment analysis, Lake
Superior special provision for
Outstanding International Resource
Waters, and important social or
economic development demonstration).
Tho decision on what constitutes the
most cost effective pollution prevention
and treatment technique's available and
whether the lowering of water quality is
minimized through the implementation
of such techniques Is left for the
Director to make on a caso-by-case basis
using best professional judgement.
EPA believes that such remedial
actions may be generally considered to
be In tho public interest, because they
are implemented to protect public
health and welfare and the
environment. Consequently, it would be
redundant to require a showing that a
remedial action is critical for important
social or economic development. EPA
welcomes comment on this position and
on tha requirements of this provision, in
general.
7. Issues
a. OiAer Options Considered for
Determining if Significant Lowering of
Water Quality is Necessary. EPA
boUaves that ths proposed prudent and
feasible pollution prevention and
alternative or enhanced treatment
techniques demonstrations, as described
above, are the most appropriate and
functional options of those considered.
However, several other approaches were
considered during the development of
tho Great Lakes Antidegradation
Guidance. One other approach
considered at length focussod on
explicitly defined economic tests as a
measure of whether the significant
lowering of water quality is necessary.
This type of "afforoability" approach is
discussed below, with an emphasis on
how it differs from the proposed
approach.
The affbrdability approaches are
typified in that they define benchmark
criteria based on specific economic
measures, to be used in determining if
the significant lowering of water quality
•is allowable. The affordability approach
considered during the Work Group
deliberations provided a criterion, based
on the cost of a facility expansion or
new development, to define the
mandatory costs to be expended on
pollution control to prevent or reduce
significant lowering of water quality. In
addition, the affordability approach
defined a second benchmark criterion
based on the financial health of a
facility or municipality that would be
used to determine if additional
pollution control expenditures, beyond
those identified as mandatory, were
affordable. Such affordable
expenditures, and the improvements in
discharge quality associated with them,
would be required by the Director.
Should such expenditures eliminate the
significant lowering of water quality, the
lowering would not be considered
necessary, and would not be approved.
A representative example of the ,
affordability approach would contain
the following elements.
First, the affordability approach
would require that the entity submit
information on pollution prevention
alternatives end-treatment techniques
that are available to the entity and
would eliminate or reduce the
significant lowering of water quality.
The information submitted would
include the cost of such measures and
their effectiveness in removing the
pollutants associated with the proposed
significant lowering of water quality,
along with specific information on the
financial health of the entity and the
cost of the expansion or development
that was proposed to significantly lower
water quality.
The Director would then conduct a
two-part analysis of this information.
First, the information would be used to
identify mandatory control
expenditures, i.e., identify a specific
dollar amount that must be spent by the
entity to reduce or eliminate the
significant lowering of water quality.
EPA considered defining the mandatory
expenditure amount in terms of a
specific ratio between the annualized
pollution control cost (capital and "
operation and maintenance costs) and
the total capital cost of the expansion or
development that would be responsible
for the significant lowering of water
quality. The analysis would then
identify alternatives that are available
within the defined cost range and the
extent to which the significant lowering
of water quality will be reduced by each
alternative. The Director would be
required to direct the entity to
implement the most effective alternative
by establishing control requirements,
such as NiDES permit limits, at the
pollutant mass loading rate achieved by
the control .alternative. If any alternative
was completely effective at preventing
the significant lowering of water quality,
then the existing control requirements
would be maintained or new
requirements established to prevent the
significant lowering of water quality,
i.e., at existing mass loading rates,
If the mandatory pollution control
expenditures did not eliminate the
significant lowering of water quality, a
second analysis of the submitted
information would be conducted to
identify any additional amount that the
entity could afford to spend on
pollution controls, in addition to the
mandatory control expenditures. EPA
considered defining the affordable
amount in terms of a specific ratio
between the annualized pollution
control cost and the annual revenues for
the entire establishment for private
entities, ;
Similarly, EPA considered a factor
based on the household burden to
define affordable expenditures for
public entities. The analysis would
identify the controls that are available
for that affordable amount and the
extent to which each would lessen the
significant lowering of water quality.
The entity would be required to
undertake additional expenditures
within the defined affordable cost range.
If significant lowering of water quality
was eliminated within this range, then
control requirements would be
established to maintain water quality;
otherwise, control requirements would
be established that reflect the most
effective of the alternatives available
within the defined affordable cost range.
The key differences between the
proposed approach and the affordability
approach discussed above are as
follows; .
i. Unlike the proposed approach, the
alternative pollution prevention and
alternatives analysis in the affordability
approach has no reference to prudent
and feasible as a criterion for the
Director's decision, nor is this analysis
limited to pollution prevention
alternatives: it also requires information
at this stage, on treatment alternatives. In
the affordability approach, this step is
simply a broad information gathering
requirement. '
ii. The mandatory pollution control
expenditures part of the affordability
approach is similar to the alternative or
enhanced treatment provision in the
proposed Guidance in that they both
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20913
establish mandatory expenditure
requirements, but they differ in several
significant respects. First, the
affordability approach would evaluate
dltypes of control alternatives,
including treatment and pollution
prevention, whereas the parallel
provision in the proposed approach
would only evaluate treatment
alternatives. Second, the cost ratios used
by the two tests are fundamentally
different. The affordability approach
would have established a cost figure
based on the size of the expansion or
development that is causing the
significant lowering of water quality,
whereas the proposed approach sets a
cost figure based on the treatment
expenditures to meet minimum state
and federal discharge requirements.
Third, the affordability approach would
have mandated the expenditure of the
identified amount regardless of the
effectiveness of the alternatives. That is,
the most effective alternative available
at the identified cost would have been
required to be implemented, even if it
would not have completely eliminated
the significant lowering of water quality,
but instead only reduced the extent to
which water quality was significantly
lowered. In contrast, the proposed
approach mandates the implementation
of alternative or enhanced treatment " .
techniques only when they are effective
at eliminating the significant lowering
of water quality.'As discussed earlier,
the Director may require expenditures
that are not mandated by this provision
in the proposed Guidance, but does so
on a case-by-case basis. EPA requests
comment on whether or not it is
appropriate to require facilities to make
expenditures of a threshold amount
even if the expenditure does not fully
eliminate the lowering of water quality.
iii. The additional affordable.
pollution control expenditures analysis
in the affordability approach, would
require that information be provided to
the Director to be used to identify any
pollution control options, beyond those
identified as mandatory, that must be ,
required of the entity, because they are
"affordable". It would lay out a cost ;
formula to be used to define how much
is affordable. In contrast, the proposed
Guidance leaves such decisions . • .
regarding affordability to the discretion
of the Director. Presumably, a
component of the prudent and feasible
pollution prevention alternatives ,
decision will involve an assessment of
affordability that will look at the ability
of the entity to pay for the alternatives.
Similarly; the final decision on controls
that might be required when there are
no identified mandatory alternative or
enhanced treatment techniques will
likely involve an affordability analysis
component. However, the proposed .
Guidance leaves the use of affordability
analyses and the criteria for determining
what is affordable to the Director's
discretion.
Various models could be constructed
to determine "affordability" in the
context of either approach. For instance,
in the enforcement context, EPA utilizes
models to determine a violator's
inability to continue in business after
achieving compliance and paying a civil
penalty. For example, one of these
models, "ABEL", assists in evaluating-
the financial health of for-profit entities.
(In the context of an enforcement
decision, EPA and the States consider
many other factors in addition to the
results of these models. Some of these
other factors include the magnitude of
the violation, the degree of
environmental damage, the entity's :
recalcitrance, and the extent of the
entity's cooperation.)
Based primarily on a determination of
solvency, such models might provide a
'partial basis for ah affordability model -
suitable for making antidegradatibn
decisions. EPA does not suggest that
such models, in and of themselves,
provide results sufficient for .making
antidegradation decisions. These tools,
however, can identify entities that might
have financial difficulty funding
additional controls. Additional financial
analyses must complement the model
results to arrive at a satisfactory
conclusion. EPA requests comments
about the suitability of these or other .
relevant models as screening devices to
determine which entities might require
more in-depth analysis.
In addition, as mentioned above,
some regulatory agencies may already
employ various methods of determining
"affordability" in the context of their
regulatory activities. EPA requests • .
comment on the experience of
regulatory agencies hi applying these
tests, including a detailed description of
the context in which they are employed
and the agency resources necessary to
carry them out.
Several concerns prompted EPA to
propose the approach in the proposed
Guidance instead of an affordability
approach. These concerns are discussed
below, along with requests for comment
on specific related issues.
The first issue is the difference in the
degree of flexibility granted to the
Director. The proposed approach
provides the Director much discretion,
in identifying what other expenditures
should be required in the event that the
mandatory expenditures do not prevent
the significant lowering of water quality.
The proposed approach focusses on >
controls that result from prudent and
feasible pollution prevention
. alternatives, but allows for a variety of
; additional considerations in the final
decision.
The affordability approach would
have, provided very specific criteria for
determining which costs are affordable
and, therefore, must be implemented
The affordability approach was
intended to represent an analytically
simple and straightforward'procedure
for evaluating whether the lowering of
water quality is necessary. However,
with each of the simplifying steps
involved, some degree of accuracy was
lost. Thus, the procedures required
qualifications, and do not take many
site-specific factors into account.
EPA is concerned that, in light of the
above qualifications, the benefits in
consistency achieved by the specificity
. of an affordability approach are
outweighed by the constraints placed on
the Director's ability to exercise best
professional judgment on a case-by-case
basis. EPA believes that this is a
significant disadvantage of the
affordability, approach and welcomes
comments on the use of specific
affordability criteria.
A second issue which led EPA to
propose the approach outlined in the
proposed Guidance rather than an ,
affordability approach involved the
States' perceptions of the level of
financial and economic analysis that it
required. The Technical Work Group
and Steering Committee representatives
frequently voiced concerns that the
financial and economic analysis
required exceeded the scope of their
normal regulatory functions (which
generally focus on Clean Water Act
programs). This potentially resource
intensive analysis could place
considerable strain on already limited
resources. EPA acknowledges this
problem and believes that the proposed
approach provides a workable solution.
However, EPA requests comments on
the experience other regulatory agencies
may have had in the application of
affordability measures and how they :
might be most effectively and efficiently
utilized. •
EPA also seeks comment on the =
potential use of a strict benefit/cost
analysis for making antidegradation
decisions. Such an analysis would not
include a mandatory expenditure oh
• pollution prevention measures. In the
proposed approach in the proposed
Guidance, regulatory agencies already
have to determine the economic and
social benefits, of the new or expanded .-
activity. They must then, compare these
benefits with the economic and social
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
costs of water quality degradation.
Social costs and benefits include the
externalities associated with a private
transaction. Social costs include such
factors as loss of aesthetics, the
destruction of habitats, the loss of a cold
water source of a game fish, and
incroasod risks to human health. Social
benefits include a community's
increased tax base that allows it to
construct new parks, rehabilitate slums,
and build recreation facilities.
In contrast to the proposed approach,
under a strict benefit/cost analysis
approach, decisions would rely entirely
on economic efficiency criteria. They
would not consider the financial
condition of the entity. For such an
approach, the proposed Guidance
would have included a method for
determining and listing social benefits
and social costs. The proposed
Guidance would have also
distinguished between economic
benefits and transfer payments. A strict
benofit/cost analysis does not include
the latter.
EPA did not propose a strict benefit/
cost analysis approach because it is
concerned that the approach would fail
to take into consideration whether a
significant lowering of water quality is
necessary* As discussed above under
"Background/Rationale", the
determination that a significant
lowering of water quality is necessary is
ono of the two mandatory
demonstrations under the existing
federal antidegradation policy. EPA
does not believe that there is any
compelling reason under the GLWQA or
the CPA to deviate from this
requirement of existing Federal
guidance. EPA considered the use of
cost/benefit analyses in a previous water
quality standards rulemaking and, in
part based on public comment, did not
include such analyses in the final rule.
The reader is referred to the preamble
discussion in the November 8,1983,
Federal Register notice (49 FR 51400)
for a more detailed discussion.
Nonetheless, EPA requests comments on
the appropriateness of a cost/benefit test
in antidegradation decision-making.
b. Economic Recovery. Concerns were
expressed during deliberations on the
proposed Guidance that it is not
sufficiently sensitive to firms that have
beon forced to reduce production as a
result of an economic downturn or
recession, and later want to increase
production to previous levels. In
particular, the Great Lakes region has
own adversely affected in recent years,
with major declines in production in
industrial sectors such as iron and steel
and automobiles and associated
supporting industries.
The proposed Guidance tries to strike
a balance between the need to protect
and maintain high quality water and the
need to accommodate growth, or in this
case promote economic recovery. The ,
proposed Guidance provides the
regulatory agency with some flexibility
that cpuld be brought into the
antidegradation decision involving a
recovering firm. For example, in the
establishment of the EEQ baseline
estimate, the proposed Guidance
provides the regulatory agency
flexibility to account for recent
economic downturns. Section D.2 of
this preamble discusses using
information from the preceding permit
term that are representative of typical
operations to determine the effluent
quality. In general, all effluent quality
data collected over the previous control
document term (e.g., past five years) that
are representative of the typical
operation of the pollutant source should
be utilized. However, the regulatory
agency could account for any recent
downturn in production by setting the
effluent quality baseline to reflect
conditions prior to the downturn, if
information was available to suggest
that it was likely to be temporary.
Similar flexibility is provided the i
regulatory agency in the establishment
of permit limits that are based on
production levels. In addition, in the
evaluation of social and economic
importance, the regulatory agency could
provide special consideration for the
recovering firm.
EPA requests comment on whether
the flexibility inherent in the proposed
Guidance is sufficient to make it
sensitive to the unique situation and
needs of the recovering firm. EPA is also
interested in comments on whether the
proposed Guidance should make special
provisions for recovering firms and
what form the provisions should take.
c. Best Available Technology. Another
issue that was raised regarding the
Antidegradation Demonstration
involves the ca,se-by-case analysis of
available pollution control alternatives
and development of EEQ restrictions.
Specifically, concerns were expressed
that, with the EEQ, pollution
prevention, and alternative or enhanced
treatment analysis requirements, EPA
was using antidegradation to require
case-by-case development of best
available technology conditions in
NPDES permits, in lieu of the
promulgation and subsequent re-..
evaluation of industry-wide guidelines
pursuant to section 304 of the Clean
Water Act.
EPA has developed effluent
guidelines for 34 primary industrial
point source discharger categories and
numerous other secondary industrial
discharger categories. Such guidelines
identify the effluent limitations
(technology-based effluent limitations)
that shall be established in NPDES
• permits issued to point source
dischargers in covered industrial
categories to ensure that such
dischargers satisfy the minimum
pollution control technology
requirements of the Clean Water Act.
Among the minimum pollution control
technology categories identified in the
Clean Water Act are best practicable
control .technology currently available,
best available technology economically
achievable, best conventional pollutant
control technology, and new source
performance standards.
EPA believes the concerns expressed
above are misplaced. The evaluation of
control alternatives and EEQ would be
required regardless of the quality of the
effluent guidelines upon which the
permits were based.
Antidegradation standards are a
component of water quality standards.
EPA and States routinely develop
effluent limitations that are more
stringent than technology-based
limitations when necessary to protect ~
water quality standards (water quality-
based effluent limitations). Specifically,
the Clean Water Act requires limitations
as necessary to meet state water quality
.standards and EPA has developed a
sizeable body of regulation and
guidance to implement this requirement
(e.g., 40 CFR 122.44(d) and the
"Technical Support Document for Water
Quality-based Toxics Control"). It is
common practice in water quality-based
permitting to require effluent limitations
that are more stringent than National
technology-based limitations as
necessary to reflect site-specific
conditions. EPA believes that
antidegradation-based EEQ or
alternative pollution prevention/control
technology requirements fall within this
context. Antidegradation requirements
such as those proposed for this ..
proposed Guidance to protect and'
maintain water quality would be
necessary regardless of how stringent
the National effluent guidelines were
made. EPA welcomes comment on this
issue.
d. Mandatory Expenditures for
Alternative or Enhanced Treatment
Techniques. As discussed above in
detail, 4he proposed Guidance
establishes the requirement that
alternative or enhanced treatment
techniques be implemented when such
techniques prevent the need to
significantly lower water quality and are
available within a specified cost range.
This provision reflects the priority of
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the Great Lakes States to create a .V. •
' mandatory expenditure policy to protect
and maintain water quality, Previous
-discussion in'this preamble addressed .
the situation in which an entity can
afford more than the additional 10 '
percent for pollution control and
treatment to prevent the significant
lowering of water quality. As that
discussion indicated, the
Antidegradatipn Decision guidance
provides the Director ample latitude to
require such additional expenditures, at
his or her discretion, to prevent or
reduce the significant lowering of water
quality. ,
The proposed Guidance, however,
provides no such latitude to the Director-
to circumvent the mandatory
expenditure requirements when the
results of the analysis .required under
section IH.B of appendix E of the
proposed Guidance show that
alternative or enhanced treatment exists
that is available within the defined cost
range and prevents the significant
lowering of water Duality. The
Antidegradation Decision guidance does
n.ot provide the Director with the ability
to determine, on a case,-by-case basis,
that the amount denneii as the ;
.mandatory expenditure is. not affordable
and, therefore, should be waived.
During GLWQI Work Group
deliberations, in considering this
position for proposal, the Steering
Committee recognized that there may he
occasions when this requirement
prevents entities from undertaking
- certain actions, which, as proposed,
would significantly lower water quality,
because they cannot afford the '
mandatory expenditure for .treatment
that would prevent the significant
lowering of water quality. In the ' ,
judgment of the Steering Committee,
this concern is more than offset by the
benefits of establishing a minimum ,
expenditure policy to protect and
maintain the quality of the Great Lakes
• System. EPA agrees with this position.
EPA invites comment on the policy
position established by the proposed
, mandatory expenditure requirements.
EPA also requests comments on the
following alternative considerations
regarding mandatory expenditures. EPA
solicits comment on whether it is
appropriate to require the mandatory
expenditures set forth in section DI.B of
appendix E only when the expenditure
prevents the significant lowering of
water quality, of if it would be
appropriate for such an expenditure to
r be mandatory if it reduced the extent to
which water quality was significantly
lowered. In the case of the latter, EPA
• also solicits comments on the extent to
which the expenditure must reduce the
significant loweringof water quality
before it becomes a mandatory
expenditure. Finally, EPA seeks .
comment on whether specific guidance
should be included to assist the Director
in. making case-by-case decisions ,
regarding expenditures greater than the
proposed mandatory amount.
e. Antidegradation Decision
Presumption Against the Significant
Lowering of Water Quality, Sections
IV. A.5 and IV.B.2 of appendix E of the
proposed Great Lakes antidegradation
guidance create an opportunity for the
Director to defer the analysis of the
social or economic developments and
environmental effects associated with
an action that significantly lowers water
quality until after opportunity for public
comment. Section IV.B.2 of appendix E
of the proposed Guidance provides that:
, If the Director chooses to defer the review
as provided in section IV. A.5 of this
appendix, then the Director shall tentatively
determine that the significant lowering of
water quality is not allowable. The public
notice shall state that the decision, based on
a review of the social or economic
developments and environmental effects
associated with the .action has been deferred,
.pending'review of the comments.ieceived
from the public, and that the tentative
decision may subsequently be revised.
This provision reflects a presumption
against .the significant lowering of water
' quality which is consistent with the
tone of the proposed Guidance, as a
• whole. It is viewed as particularly
important at the stage of the decision
procedure when the public is asked to
comment on the merits of a proposed
action that would significantly lower
water quality. During, deliberations at ;
TechnicalWork Group meetings and
Steering Committee meetings to develop
this proposed Guidance, several of the
State representatives expressed concern
that they needed the input of the public
before they could do a meaningful ;
assessment of the importance of the
social or economic developments
associated with a proposed action that
would significantly lower water quality.
However, in order to receive such input,
within the public participation
processes established for many of the
existing regulatory programs, it would
be necessary to propose a tentative
.decision regarding approval or
disapproval of the request to :
significantly lower water quality to put
out for public comment. The Steering ;
Committee and EPA agreed that it was
appropriate for the tentative decision
put forth for public comment to be a
denial, since, at that point there would
be insufficient public input to ascertain
that the social or economic development
. resulting from the proposed significant
lowering of water quality would be : ,
important. To create a new public
comment step outside of the .existing
procedures was an option, but it was
considered too burdensome to the
regulatory agencies to be feasible and a
significant hinderance to timely
decision-making.
Again, this provision represents the • . - .
choice of the Steering Committee, with
which EPA agrees, to presume that
water quality be maintained and .--.:'
protected unless the public believes that
the social or economic development that
necessitates its significant lowering is
important enough to support. EPA
welcomes comments on this provision
in the proposal, and on the position
established by it.: • ' •. .
G. Special Antidegradation Provisions
for Lake Superior
1. Background
As stated earlier in this preamble
; discussion, in September 1991, the /
States of Michigan, Minnesota, and
Wisconsin/the Province of Ontario, the
government of Canada, and EPA entered
into an agreement entitled "A Bi- -•'
National Program to Restore and Protect •
the Lake Superior Basin." This
agreement established a "Lake Superior
Zero Discharge Demonstration Program"
. with the stated goal being "To achieve
zer,o discharge and zero emission of
certain designated persistent, .,,':;-.
bioaccumulativetoxic'substances,
which may degrade the ecosystem .of the
Lake Superior basin," The agreement
identified three areas in which the
parties agreed to undertake actions to
pursue realization of this.goal, one of
which, "Special Protection ,
Designations", is significant to this
proposal. Under the.Special Protection
Designation heading, the Governors of
the three Great Lakes States of
Michigan, Minnesota, and Wisconsin
("Lake Superior States") commit to
initiate appropriate State procedures to
designate all waters of the Lake Superior
Basin as Outstanding International
• Resource Waters (OIRWs) and certain
special areas of the Lake Superior Basin
as Outstanding National Resource
Waters. The agreement further defines
the intent and effect of such -•.-.'.'
designations:
Under the OIRW designation, the ..",
increased discharge of certain
designated persistent, bioaccumulative
toxic substances will not be allowed
without an adequate antidegradation
demonstration which includes the
installation of the best technology in
process and treatment.
The purpose of this Lake Superior
:Basin-r-Outstanding National Resource
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Water designation is to prohibit the new
or increased discharges of certain
designated persistent, bioaccumulative
toxic substances by point sources in
these areas, including respective buffer
zones and transition areas as defined by
the States.
Tha agreement requires that
procedures to implement each
designation be incorporated into the
Great Lakes Water Quality Initiative
Antidegradation Guidance.
2. Effect
This proposed Guidance contains
several provisions, developed by the
Lake Superior States and enumerated
below, to implement the above
conditions in the agreement. These
provisions operate as additional
restrictions, beyond the minimum
requirements of the National
antidogradation regulation, as this
proposed Guidance has adapted it to
apply to the entire Great Lakes System.
Consequently, this notice puts these
special Lake Superior provisions
forward as State proposals, which EPA
considers acceptable pursuant to section
510 of the Clean Water Act. The special
provisions of this proposed Guidance
included to implement the Lake
Superior Special Protection
Designations are as follows:
Appendix E, section H.A. Definition
of Lake Superior bioaccumulative
substances of immediate concern;
Appendix E, section n.A. Definition
of Lake Superior Basin—Outstanding
National Resource Waters;
Appendix E, section II.E.1 and E.2.
Implementation procedures, entitled
"Special Provisions for Lake Superior"
that identify the effect of Lake Superior.
Special Protection Designations;
Appendix E, section m.
Antidegradation Demonstration text
reiterating the actions within the Lake
Superior Basin, if designated an OIRW,
that would necessitate a special
demonstration by the entity proposing
the action;
Appendix E, section m.C. Description
of the special demonstration that must
be provided by an entity proposing a
new or increased discharge of Lake
Superior bioaccumulative substances of
immediate concern to the Lake Superior
Basin, if designated an OIRW;
Appendix E, section IV.A.3.
Antidegradation Decision provision to
ensure that the Director requires
installation and utilization of best
technology in process and treatment by
entities mat lower water quality as a
result of the new or increased discharge
of any Lake Superior bioaccumulative
substance of immediate concern into the
Lake Superior Basin, if designated an
OIRW.
EPA notes that the Lake Superior
special provisions in the
antidegradation guidance are operative
only when States designate waters of the
Lake Superior basin as either Lake
Superior Basin - Outstanding National
Resource Waters or OIRWs. The
proposed Guidance does not direct or
require the Lake Superior States to make.
such designations.
Several of the above provisions
require additional discussion to
differentiate them from conditions more
broadly applicable to the Great Lakes
System and to describe how the special
provisions operate within the larger
antidegradation framework.
a. Relationship to Other
Antidegradation Requirements. As
indicated above, the special provisions
applicable to designated portions of the
Lake Superior Basin operate in addition
to the antidegradation provisions
otherwise applicable. Section HE of
appendix E of the proposed Guidance
explicitly states this relationship.
i. Example. Upon designation of the
Lake Superior Basin as an OIRW by the
Lake Superior States a proposal by a '
point source to increase the discharge
rate of mass loading of BCCs, which also
includes certain Lake Superior
bioaccumulative substances of
immediate concern (BSICs), into an area
of the basin that is a high quality water
with respect to the pollutants in
question would be covered as follows.
- The proposal would necessitate an
antidegradation demonstration, because
it involves an increase in the rate of
mass loading of BCCs (pursuant to
section II.D.1 of appendix E) and an
increased discharge of BSICs from a
point source (pursuant to section HE.2
of appendix Ej.
The demonstration would evaluate,
pursuant to section HI.A of appendix E
of the proposed Guidance, pollution
prevention alternatives available for all
the pollutants, BCCs and BSICs. If
prudent and feasible pollution
prevention alternatives prevent the
significant lowering of water quality (or
increased discharge in the case of the
BSICs), then the entity would not be
required to provide any additional
antidegradation demonstration
information, because the significant
lowering of water quality would not be
allowable.
The second step of the demonstration
differs between the BCCs and the BSICs.
For BCCs not on the list of BSICs, the
demonstration would evaluate
alternative or enhanced treatment
techniques available to prevent the
significant lowering of water quality and
identify the associated costs as specified
in section m.B of appendix E of the
proposed Guidance.,If the costs were
within the range defined by section ffl.B
of appendix E of the proposed
Guidance, no further antidegradation
demonstration information would be
required'of the entity regarding the
BCCs, because the significant lowering
of water quality would not be allowable.
For the BSICs, the demonstration would
identify and evaluate the effectiveness '
of the best technology in process and
treatment. The proposed Guidance
leaves the determination of what
constitutes best technology in process
and treatment to the individual Lake
Superior States, with the understanding
that it will always be at least as stringent
as the alternative or enhanced treatment
identified for pollutants other than
BSICs, that the cost of the technologies
is not a factor in the decision, and that
in general the requirement is intended
to force implementation of "state of the
art" pollution controls.
In the third step, where the
application of alternative or enhanced
treatment techniques available within
the mandatory cost range does not
prevent the significant lowering of water
quality by BCCs or the implementation
of best technology in process and
treatment does not prevent the
increased discharge of BSICs, the entity
must provide the important social or
economic development demonstration
required by section Etl.D.of appendix E
of the proposed Guidance. This
information is evaluated in the same
manner for all pollutants.
Finally, section IV.A.1 of appendix E
of the Antidegradation Decision
instructs the Director to require the
implementation of prudent and feasible
pollution prevention alternatives for
both types of pollutants. The
information developed in the second
step is handled in separate provisions in
the Antidegradation Decision part of the
proposed Guidance. For the BCCs,
section IV.A.2 of appendix E of the
proposed Guidance provides that the
Director must deny the request to
„ significantly lower water quality if
alternative or enhanced treatment
technologies exist, the cost of such
treatment falls within a defined range
and its implementation prevents the
significant lowering of water quality.
For the BSICs, section IV.A.3 of
appendix E of the proposed Guidance
provides that the Director must require
the installation and utilization of the
. best technology in process and
treatment and establish limitations on
the BSICs accordingly, In section IV.A.4
of appendix E of the proposed
Guidance, actions that are not prevented
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Federal Register / Vol. 58, No. 72 /, Friday, April 16, 1993 /: Proposed Rules 20917
from significantly lowering water
quality (or increasing the discharge of .
BSICs) by the decisions in section
IV.A.-1 through A.3 of appendix E of the
proposed Guidance are evaluated in •
light of the associated social or
economic developments and i
environmental effects and a decision
proposed regarding the extent to which
water quality may be significantly
lowered (or the discharge of BSICs
increased). Both actions involving BCCs
and BSICs are subject to this evaluation.
As discussed in detail elsewhere in this
preamble, as a result of this evaluation
the Director may require other controls
on BCCs on a case-by-case basis _,
provided they are no less stringent than
the controls required under section f
IV.A.2 of appendix E of the proposed
Guidance.
b. Lake Superior Basin—Outstanding
National Resource Waters. The special
provisions created for Lake Superior
define a potential new State
designation, that of Lake Superior
.Basin—Outstanding National Resource
Water, and specify the effect of such a
designation (see sections II.A and n.E.l
of appendix E of the proposed
Guidance, respectively). EPA wants to
clarify that this new designation created
for Lake Superior is different than the
' Outstanding National Resource Water
designation defined in section II.A of
appendix E of the proposed Guidance.
The terminology for the Lake Superior
designation was chosen by the Lake
Superior States to conform as closely as
possible" to the language in the
agreement, while still being .
distinguishable from the ONRW ;
designation defined in the National
antidegradation. regulation and. used in
this proposed Guidance. EPA also notes
that the creation of the new Lake
Superior Basin—Outstanding National
Resource Water designation does not
affect the ability of a State to designate
a portion of the Lake Superior Basin as
an ONRW (as defined in section II.A. of
appendix E of the proposed Guidance)
and that such a designation would have
the effect specified in section II.C of
appendix E of the proposed Guidance.
! c. Lake Superior Bioaccumulative
Substances of Immediate Concern. '•'•'
Section !L A of appendix E of tlae .
antidegradation guidance identifies the
substances that are subject to the special
Lake Superior provisions of the : - =
proposed Guidance. These substances
' were identified in the agreement and are
.proposed by the Lake Superior States for
this proposed Guidance, because they
are the persistent, bioaccumulative toxic
' pollutants considered to pose the most
significant ri$k to the Lake Superior
Basin. The proposed Guidance provides
that additional substances may be added
by a State in the future, after the
opportunity for public review and
comment. EPA wants to clarify that
designation as a Lake Superior
bioaccumulative substance of
immediate concern has no effect on the
status of such pollutants in Lake
Superior Basin waters not designated'as
Lake Superior Basin—Outstanding
National Resource Waters or OIRWs or
in other waters of the Great Lakes
System. '- .-".-". ,
EPA invites comment on all aspects of
the special provisions for Lake Superior.
H. Offsets
During Technical Work Group
deliberations on the GLWQI, ah
approach was evaluated that would
have required, as a^ part of the
antidegradation review, ^consideration of
controls on unregulated pollutant
sources to offset proposed increased
discharges from a regulated source. The
approach was referred to as "offsets",
and it was intended to provide the
Director with an additional mechanism
to prevent significant lowering of water
quality.. 1 . ' , . -
The offset approach would have
required that an entity seeking to
significantly lower water quality with
respect to any pollutant, identify other
sources, currently not subject to
regulation, of that pollutant to the water
body in question. The entity would be
required to determine if any such
sources were amenable to control such.
that the reduction in the loading from
the unregulated source would offset the
proposed increase in loading from the
entity. If the opportunity for such offsets
was found and incorporated as an
enforceable requirement of the entity's
control document (e.g., NPDES permit) •
the entity could avoid the additional
antidegradation demonstration
requirements in the Great Lakes
Antidegradation Guidance. That is, the
Director could in such a case determine'
that .water quality was not significantly
lowered. One variation to the general
offset approach considered by the
GLWQI Technical Work Group is
highlighted for comment. The Technical
Work Group considered requiring that
additional removals of BCCs be
mandated under the offset provision in
order for an-action to be relieved of
further antidegradation demonstration
requirements. That is, the entity seeking
to increase its mass loading rate of a
BCC would have been required to find
and control unregulated, uncontrolled
sources of that BCC in an amount
greater than the proposed increase, in
order for the increase to be considered
offset. Several alternative factors were
considered, ranging up to 1.5,"which
would have mandated 1.5 times the
amount of the proposed increased rate
of pollutant loading be removed from
currently unregulated, uncontrolled
sources to achieve an offset.
EPA is not proposing any offset
provision in the Great Lakes ;
Antidegradation Policy in the Federal
Register notice. In the GLWQI
deliberations, EPA and the Great Lakes
States shared concerns that • . •
implementation of the offset concept is '
not yet technically feasible or legally
enforceable. That is, although .
conceptually possible, it was expected
to be too difficult to quantitatively
implement and enforce the concept of,
offsets. In particular, the likelihood that
controls on currently unregulated, '"'';.'
uncontrolled sources could be an '.
enforceable requirement of a permit was
strongly questioned and anticipated to ~ ;
result in excessive administrative
burdens. In addition, the likelihood that
an entity seeking an increased discharge
could identify and control an
unregulated source of contamination ,,
; was questioned by many Work Group
members; . :
.Although the offset concept is not
being proposed in the Great Lakes :
Antidegradatiori Policy, other parts of
the Great Lakes Water Quality Guidance
may allow "trading" of pollutant load
allocations between pollutant sources,
'both point and nonpoint. In particular
the reader is referred to the discussion
of TMDLs in the implementation '•':
procedures (see section VULC of this: :
preamble). However, any such
reallocation of pollutant loads to
pollutant sourc'es might subject them to
the requirements of this :
Antidegradation Policy.
EPA requests comment on the offset
approach considered for the Great Lakes
Antidegradation Policy. EPA also
solicits comment on any information ,
that regulatory agencies may have on
actual experience using an offset
approach to control pollution sources,
J. Incorporation Into State Water Quality
Standards. .
The Great Lakes Critical Programs Act
requires the Great Lakes States to adopt
antidegradation policies for the Great'..
Lakes System that are consistent with
the final Great Lakes'Guidance
published by EPA. The Federal Register
notice proposes such Guidance. When
evaluating whether or not the, States
adopt antidegradation policies that are •
consistent with the final Great .Lakes , .-.'-
Water Quality Initiative Antidegradation
Policy, EPA will follow the .provisions
of 40 CFR 132,6, proposed in the ;
proposed Guidance; ._•.,-.. ;-1
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20918
Federal Register / Vol. 58, No. 72 /Friday, April 16, 1993 / Proposed Rules
EPA expects Chat upon finalization of
the proposed Guidance, the States will
adopt into their water quality standards
regulations language identical to or no
less restrictive than the language set
forth in the Great Lakes Water Quality
Initiative Antidegradation Policy
(appendix E to part 132). Specifically,
tho States must adopt into their water
quality standards regulations the
Antidegradation Standard,
Antidegradation Implementation
Procedures, Antidegradation
Demonstration, and Antidegradation ••
Decision provisions of the final
Guidance. EPA believes that these
provisions collectively represent the
AnUdegradaUon Policy required by the
Great Lakes Critical Programs Act. The
State regulations need not reproduce,
verbatim, the Great Lakes Guidance.
However, the antidegradation policy
adopted into State regulation must
result in equal protection and
maintenance of water quality as would
this proposed Guidance in the same
situation.
As indicated in proposed 40 CFR
132,4(a)(6), the Great Lakes States are
not required to adopt the provisions of
the Antidegradation Policy that provide
special protection to Lake Superior.
These provisions are enumerated in 40
CFR 132,i(a)(6) and discussed in this
preamble isea section Vn.G.2.). EPA is
including these provisions in the
Antidogradation Policy to provide
guidance to the Great Lakes States
signatory to the "Bi-National Program to
' Restore and Protect the Lake Superior
Basin." EPA does not intend to
promulgate the Lake Superior special
provision of the Antidegradation Policy
pursuant to proposed 40 CFR 132.5(d) if
a Great Lakes State fails to do so.
At several points in this preamble,
various alternatives are identified to
accomplish specific requirements set
; forth in the proposed Guidance (e.g.,
options for EEQ controls). A State is free
to implement the requirement using the
identified alternatives or others that
may be equally effective. Finally, there
are a numoer of decisions required by
the proposed Guidance which allow the
Stale to exercise flexibility in response
to situation-specific conditions (e.g., the
determination of what constitutes
, "prudent and feasible" pollution
prevention alternatives). As noted in the
preamble, EPA is requesting comment
on whether the proposed Guidance
provides adequate direction to the
States for making such decisions.
A State may adopt an antidegradation
policy for the Great Lakes System,
which is more stringent than that
spocifiod in the proposed Guidance.
Finally, to the extent that a State can
demonstrate that its current water
quality standards regulations or statutes
contain some of all of the proposed
Guidance being proposed here for the
Great Lakes System, the State need not
reproduce that portion of the proposed
Guidance as separate Great Lakes
standards.
. General Implementation
Procedures
A. Site-Specific Modifications to Criteria
National guidance provided in the
"Water Quality Standards Handbook"
(1983) (the Handbook) indicates that
States may modify generally applicable •
State criteria and set site-specific water
quality criteria for the protection of
aquatic life when: the local water
quality parameters such as pH,
hardness, temperature, color, etc., alter
the biological availability and/or
toxicity of a pollutant; and/or the
sensitivity of the local aquatic
organisms (i.e., those that would live in
the water absent human-induced
pollution) differs significantly from the
species actually tested in developing the
criteria. This Handbook is available in
the administrative record for this .
rulemaking. Copies are also available
upon written request to the address
listed in section XIH of this preamble.
State-wide water quality criteria for
aquatic life may be unnecessarily
stringent or underprotective in a given
water body if the physical and chemical
characteristics of the water body
ameliorate or enhance the biological
availability and/or toxicity of a given
chemical. In addition, species capable of
living at a particular site, if there were
no human-induced pollution, may be
more or less sensitive than those species
represented in the development of the
State-wide criteria. Developing site-
specific criteria for aquatic life is a way
of taking unique conditions of a specific
portion of a water body into account so
that criteria adequately protect aquatic
life from acute and chronic effects.
Chapter 4 of the Handbook provides
procedures for setting site-specific
criteria for aquatic life which may be
utilized as a basis for establishing water
quality standards. Using those
procedures, the resulting chronic or
acute aquatic life criteria may be more
or less stringent than the otherwise
applicable State criteria.
There is presently no such specific
guidance regarding site-specific „
modifications to human health water
quality criteria. Additionally, there is
presently no National guidance for
deriving wildlife water quality criteria
or site-specific modifications to wildlife
criteria. However, present regulations
do allow States to modify any criteria to
reflect site-specific conditions provided
that the modified criteria are protective
of designated uses and based on sound
scientific rationale (40 CFR 131.11). One
of the issues that States might consider
in developing site-specific
modifications to human health criteria,
for example, is local fish consumption
rates. (See, generally, memorandum
from Lajuana S. Wilcher to Regional
Water Management Division Directors,
dated January 5,1990, which is
available in the administrative record
for this rulemaking.)
National water quality criteria are
based upon data from, and assumptions
specifically applicable to, the entire
United States. The Great Lakes criteria/
values proposed in the proposed
Guidance differ from the National
criteria in part because they were
derived using data and assumptions
relevant to the Great Lakes System. For
example, certain aquatic life criteria/
values have been lowered to protect
commercially or recreationally
important species within the Great
Lakes System (e.g., steelhead rainbow
trout). As another example, BAFs used
in developing human health, criteria/
values for the Great Lakes System
assume a fish lipid content of five
percent based on Great Lakes-specific
data instead of the National average
lipid content of three percent used for
the derivation of National criteria. The
purpose of using Great Lakes-specific
data and assumptions in deriving
criteria/values is to more accurately
calculate ambient criteria levels that are
protective of aquatic life, wildlife and
humans within, the Great Lakes System.
Even though the Great Lakes criteria/
values already reflect Great Lakes-based
modifications of, the National criteria,
there may be local areas within the
Great Lakes System where conditions
vary sufficiently from the assumptions
underlying the methodologies for
deriving Tier I criteria and Tier n values
to merit the application of more
narrowly applicable site-specific
criteria. Procedure 1 of the proposed
Implementation Procedures specifies
the circumstances where a State may
develop site-specific modifications to
the Great Lakes aquatic life, human
health and wildlife criteria as well as .
bioaccumulation factors. The proposed
Implementation Procedures allow
modifications to be made to acute or
chronic aquatic life criteria/values in a
manner consistent with Chapter 4 of the
' Handbook, This Handbook only covers
site-specific water quality criteria for the
protection of aquatic life. Consistent
with that guidance, site-specific
modifications to acute and chronic
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Federal Register 7 Vol. 58', No. 727 Friday, April 16, 1993 / Proposed Rules.
20919
aquatic life criteria/values for the Great
Lakes System under the proposed
Guidance may result in more or less
stringent aquatic life criteria/values than
those calculated using the Great Lakes
aquatic life methodology.
, The Handbook only sets forth
procedures for developing site-specific ,
modifications to aquatic fife criteria
when such modifications are . "
appropriate because either local water
quality parameters alter the biological"
availability or tpxicity of a pollutant, or
the sensitivity of local aquatic •
organisms differ significantly, from the
species actually tested in developing
criteria. Proposed implementation _
proqedure 1, however, goes beyond the/
Handbook by also allowing the Great
Lakes States and Tribes to deveslop site-
specific modifications to chronic
aquatic life criteria/values for the Great
Lakes System to reflect local physical
and hydrologic conditions. Specifically,
the Great Lakes States and Tribes would
• be allowed to also develop site-specific
modifications to chronic aquatic life
criteria/values by showing that either
hydrologic conditions or physical
conditions related to the natural features
of a water body, such as lack of a proper
substrate, cover, flow, depth, pools,
riffles, and the like, unrelated to
ambient water quality, preclude aquatic
life from remaining in the site for 96
hours or more. These site-specific
conditions may also be taken into
account in determining whether a
discharge must comply with the chronic
whole effluent toxicity requirements
specified in proposed procedure 6.A.2., .
This provision is discussed in section
Vin.F of the preamble. ,-
"As explained above in the section of
ibis-preamble on the Applicability of
the Tier I and Tier II Criteria/Values, the
Initiative Steering.Committee intended
that the States be given additional
flexibility to modify chronic aquatic life
criteria/values where physical and
hydrologic conditions prevent aquatic
life from remaining in a specific water
body for 96 hours or more. The Steering
. Committee was concerned that the
chronic aquatic life criteria/values
would be unnecessarily stringent in
protecting aquatic life in such locations
because the chronic aquatic life
methodologies assume that aquatic life
are exposed to pollutants in a specific
water body for at least 96 hours.
Consistent with the Steering Committee
deliberations, the proposed Guidance
allows the States to develop site-specific
modifications to the chronic aquatic life
criteria/values to reflect local physical
and hydrologic conditions.
* EPA believes that it is possible that
there may be sites within the Great • ,
Lakes System where aquatic life willnot
remain at the site for more than 96 ..
hours. Consequently, aquatic life can be
protected from suffering chronic health
effects at such sites by criteria/values
less stringent than those developed
under the proposed Great Lakes
Guidance. Similarly, in sites where
conditions preclude all but a few forms
of aquatic life from living in a specific
site, it is possible that the few, forms of
aquatic life living at the site may be
protected by less stringent criteria/
values. Because the physical and
hydrologic condition justification for
the exception to procedure 6.A.2 of
appendix F is functionally equivalent to
a justification for the removal of a
designated use at 40 CFR 131.10(g)(2), ,
(4) and-(5), EPA'expects this exception
will typically be used for waters where
a full aquatic life use is unattainable.
States must ensure that the application
of this exception does not impair the -•
water quality _of downstream waters.
The proposed Great Lakes Guidance
does not provide for the same flexibility
in terms of site-specific modifications to
the wildlife and human health criteria/
values or to bioaccumulation factors as
is available for aquatic life criteria/
values. The proposed Guidance restricts-
site-specific modifications to human
health criteria/values, wildlife criteria/
values, or bioaccumulation factors to
only those which would increase the
level of protection for humans and
wildlife. The proposed Guidance, in
allowing States to adopt less stringent
criteria/values for aquatic life, but not .
for human health and wildlife,.is
consistent witbrthe Steering
Committee's proposal. ••'-;
EPA believes that although less
stringent site-specific criteria/value
modifications can be justified for
aquatic life,, similar justifications may
not exist with respect to less stringent
wildlife and human health criteria/
values or BAFs. For example, EPA does
not believe that there are natural
conditions in the Great Lakes System
which preclude humans and wildlife
from consuming fish and recreating in
specific sites. Similarly, even if there
maybe local populations of humans and
wildlife less exposed to toxicants than
assumed in deriving the State-wide
criteria, a less stringent site-specific
, modification may not be appropriate
given the mobility of humans and
wildlife into and out of these localized
areas. Instead, EPA assumes that, due to
.their mobility, humans and wildlife feed
from .and recreate in all portions of the-
Great Lakes System. EPA believes that
these assumptions are reasonable and
appropriate in light of the goals and
objectives of the Clean Water Act and ,
.the Great Lakes Water Quality
Agreement. However; EPA requests
comment on these assumptions.
, The proposed Guidance allows Great
Lakes States and Tribes to adopt site-
specific modifications allowing for
application of less stringent aquatic life
'criteria/values where local water quality
parameters alter the biological
availability and/or tpxicity of a
pollutant, but does not allow similar
site-specific modifications for human
health and wildlife criteria/values. This
proposal is consistent with the proposal
of the Steering Committee. In those
cases where the biological availability
and/or toxicity of a pollutant is.
decreased by local water quality
conditions (e.g., pH, hardness,
alkalinity, suspended solids), a less ;
stringent criteria/value for aquatic life
will adequately protect aquatic
organisms. The proposed Guidance ,
reflects a more conservative approach
with respect to humans and wildlife by
allowing only more stringent site-
specific modifications. EPA believes
that this conservative approach is •
appropriate because of the mobility of,
humans and wildlife and their potential
for exposure to these pollutants in
different areas of the Great Lakes basin.
In addition, there is not adequate
information to quantify the total
environmental uptake by humans and
wildlife from different exposure routes.
In light of these uncertainties, EPA
proposes to use an approach that may
result in human health, and wildlife
criteria/values which are somewhat
overprotective in those cases where
local water quality parameters decrease
the biological availability and/or'
toxicity of a water body. This approach
would err on the side of being '
overprotective rather than
underprotective. EPA invites Comment _
on whether the proposed approach for
humans arid wildlife is reasonable or
"whether less stringent site-specific
modifications should be allowed under
certain circumstances.
Specifically, EPA requests comment
on whether the proposed Guidance ,
should be modified to allow for
development of less stringent site-
specific modifications to all types of ;
criteria/values (including human health
;and wildlife) arid BAFs under any of the
• scenarios described below or under any
• other scenarios. Comment is requested
on whether less stringent site-specific
modifications should be allowed for ,
human health and wildlife criteria/
values where local water quality .
parameters decrease the biological
availability and/or toxicity of a - -
pollutant. EPA invites specific comment
on adding to the human health and
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20920
Federal Register / Vol. 58, No. 72 I Friday, April 16, 1993 / Proposed Rules
wildlifa provisions the sarao text as -
appears in section A.l.a of procedure 1
of appendix F for aquatic life. EPA also
Invites comment on whether less
stringent site-specific modifications
should ba allowed for bioaccumulative
pollutants where local physical or
hydrologic conditions do not allow
aquatic life that may he consumed hy
humans or wildlife to ha present in the
water hody long enough to reach steady-
state Woaecumulation. EPA further
invites comment on whether less
stringent site-specific modifications
should ba allowed for bioaccumulation
factors if reliable data shows that local
bioaccumulation is lower than the
system-wide value.
EPA also invites comment on whether
it should allow in the final Great Lakes
Guidance the development of less
stringent site-specific modifications to
the aquatic life criteria/values, as
proposed today. Eliminating the option
would enhance consistency of criteria in
the Great Lakes System.
The proposed Guidance for wildlife
criteria/values states that modifications
may be made on a site-specific basis to
provide an additional level of protection
for a species determined to require
greater protection, for any reason. The
proposed Guidance specifies that such
site-specific modifications may be
accomplished through the incorporation
of an additional uncertainty factor in the
_ (NOAEL X SSF x ISF) x WtA
WA-f(FAxBAF) _
equation for the wildlife value. The text
presented below provides additional
guidance on the equation for the
calculation of the wildlife value and is
in keeping with the intent of the
Initiative Committees. EPA requests
comment on the use of the following-
alternate text to replace the text of
procedure 1.A.2 of appendix F of the
proposed Guidance.
Wildlife criteria or values may be modified
on a site-specific basis to provide aa
additional level of protection for a species ,
determined to require greater protection, for
any reason. This may be accomplished
through the use of an additional uncertainty
factor in the equation for the wildlife value •
as presented below:
where:
The terms are defined in appendix D,
section II of the proposed Guidance
except that:
NOAEL=No Observed Adverse Effect
Level in milligrams per kilogram
body weight per day (mg/kg/d)
determined for the taxonomic class
to which the species requiring
greater protection belongs.
WtA-Averaga weight in kilograms (kg),
of the species requiring greater
protection,
WA=Average daily volume of water
consumed by the species requiring
greater protection, In liters per day.
FA«Average daily amount of food
consumed by the species requiring
greater protection, in kilograms per
day(kg/d).
BAFaAquatic life bioaccumulation
factor in liters per kilogram (L/kg)
for the trophiclevelfs) at which the
spodes requiring greater protection
faeds. The BAF is chosen using
guidelines for wildlife presented in
appendix B, section V.B of the
proposed Guidance.
ISF«Intraspecies sensitivity factor. An
uncertainty factor to account for
differences in toxicologies!
sensitivity among members of the
population of the species requiring
greater protection (maybe 0.1 or
less).
The aquation presented above for the
calculation of a site-specific wildlife
criterion for species requiring greater
protection incorporates the use of the
NOAEL determined for the taxonomic
class to which the species requiring
greater protection belongs. It is possible
that the site-specific wildlife criterion
may be based on a species from a
different taxonomic class than the
wildlife value used to derive the State-
wide wildlife criterion. However, site-
sp ecific modifications may only be
made when the site-specific wildlife
criterion which results is more stringent
than the State-wide wildlife criterion. In
addition, the above equation for the
wildlife value includes an intraspecies
sensitivity factor (ISF) to provide
additional protection to individuals in a
population since the proposed wildlife
methodology is derived to protect
wildlife populations, not individuals'
within the population. Therefore, EPA
highlights the use,of site-specific
modifications for the protection of
individuals within a population for
species requiring greater protection for
public comment
Section IT.K of today's preamble states
that EPA has initiated informal
consultation with the FWS to ensure
that the requirements in part 132 are not
likely to cause jeopardy for threatened
or endangered species in the Great
Lakes System. EPA invites comments on
whether procedure 1 in appendix F to
part 132 should contain specific text
requiring modification on a site-specific
basis of aquatic life and wildlife criteria/
values to provide protection appropriate
for threatened or endangered species.
Individual Great Lakes States may
make a decision to modify any aquatic
life, human health or wildlife criterion/
value consistent with the requirements
of this guidance. Site-specific
modifications to criteria must be
submitted to EPA for approval or
disapproval in accordance with section
303(c) of the Clean Water Act and 40
CFR 131.20. Iri. addition, the proposed
Guidance would require that the State
share information concerning site-
specific modifications to Great Lakes
criteria/values with other Great Lakes
States. The State must notify the other
• Great Lakes States at the time a State
proposes any site-specific modification
and supply a justification for any less
stringent site-specific modification. The
State may send a notice to the
appropriate State agency designee's and/
or notify the EPA Region V
Clearinghouse to comply with this
requirement. The purpose of the notice
is to allow other Great Lakes States to
comment on proposed site-specific
modifications to criteria/values since a
primary objective of today's proposed
Guidance is to provide consistency
among the Great Lakes States.
EPA invites comment on two possible
alternatives to the proposed procedure 1
of appendix F. Under the first
alternative, site-specific modifications
as provided in procedure 1 would be
available only for tributaries and
connecting channels, not the open
waters of the Great Lakes. This first
alternative was developed by the
Technical Work Group, which felt that
the Great Lakes criteria provide
appropriate protection for the open
waters of the Great Lakes and that the
proposed procedure 1 should only be
used for rather small localized areas to
provide needed additional protection of
specific subpopulations within those
areas and, for aquatic life, limited less
stringent modifications. The reason for
the Work Group's proposal was to
ensure that a consistent set of
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Federal Register / Vol. 58, :No. 72 / Friday, April 16, 1993 / Proposed Rules 20921
requirements is applied throughout the
open waters of the Great Lakes.
Although EPA recognizes that one of
the goals expressed in the legislative
history of the Great Lakes Critical
Programs Act of 1990 is to promote,
consistency in Great Lalces water quality
standards, EPA does not view this goal
as overriding the authority specifically
reserved to States and Tribes in section
510 of the Clean Water Act to enact
more stringent requirements than
necessary to implement Clean Water Act
requirements. Furthermore, Article IV(a)
of the Great Lakes Water Quality
Agreement also clearly provides that the
Agreement is not intended to preclude
adoption of more stringent . ,
requirements. Consequently, EPA is not
authorized under the Clean Water Act to
prohibit States from adopting more
stringent criteria/values for the open,
waters of the Great Lakes System. For
these reasons, EPA is not proposing this
first alternative in today's proposed
. Guidance. Nevertheless, EPA invites
comment on this first alternative, and
on EPA's interpretation of the Clean
Water Act. . •' •
A second altemative.would provide
that the site-specific modification
procedures in procedure 1 of appendix
F would differ for pollutants that are not
bioaccumulative chemicals of concern
(BCCs). For non-BCCs, this.alternative
approach would allow site-specific
modifications for human health and
wildlife criteria/values that are either
more stringent or less stringent than the
criteria/values derived using the
proposed Guidance methodologies,
depending on local considerations (e.g.,
water quality characteristics). This
alternative approach would provide .
additional flexibility to the States in
conducting site-specific modifications
for rion-BCCs.
This second alternative was not
viewed favorably by the Great. Lakes
Steering Committee. EPA is proposing
today that only those site-specific
modifications which result in more
stringent human health and wildlife
criteria/values be allowed under the
proposed Great Lakes Guidance,
consistent with the Steering Committee
proposal. However, EPA invites
comment on this possible alternative
. approach. •
B. Variances From Water Quality
Standards for Point Sources.
. , The proposed Water Quality
Guidance for the Great Lakes System
proposes Guidance to be followed by
the Great Lakes States and Tribes in the
development of procedures for granting
• variances from 'water :quality standards
for point sources at 40 CFR p;art 132,
appendix F, procedure 2. This proposed
Guidance is not intended to require the
States or Tribes to include a variance
provision as part of their standards
program. Rather, EPA is proposing to
permit Great Lakes States and Tribes to
include water quality standards
variance provisions in their water
quality standards,-and grant variances
based on those provisions, as long as
they are at least as stringent as those
proposed herein. The proposed water
quality standards variance procedure
provides a mechanism for States and
Tribes to maintain goal standards and
assure compliance with.sections
301(b)(l)(C) and 402(a)(l) of the CWA
that require NPDES permits meet
applicable water quality standards,
while granting temporary relief to point
source dischargers.
The intent of the variance provision is
to: Provide a mechanism by which .
permits can be written to meet a,
modified standard where compliance
with the underlying water quality
standard is demonstrated to be
infeasible; encourage maintenance of
- original standards as goals rather than
removing uses; identify conditions
under which such variances may be ,
granted; identify the requirements for
variance applications; and ensure the
highest level of water quality achievable
while tiie variance is in effect.
1. Current EPA Policy
For some time, EPA has
acknowledged State or Tribal authority
to grant variances from water quality
standards and has approved both State-
- adopted variances procedures and State-
issued individual variances. Because the
Clean Water Act does riot speak directly
to water quality standards variances and
EPA's regulations merely allow States to
adopt variance provisions subject to
' EPA approval, the permissible scope of
water quality standards variances must
be discerned from the general structure
of the Clean Water Act and by analogy.
This process,,conducted over the past
15 years, has resulted in a variety of
guidance and interpretive documents
which, together, set out the evolution of
EPA's current policy on water quality
' standards variances. •
EPA first formally indicated
allowability of State water quality
. standards variance provisions in
Decision'of the General Counsel No. 44,;
dated June 22,1976, which specifically
considered an Illinois variance
provision. EPA expanded upon the
acceptability of State water quality
standards variance procedures in \ /
Decision of the General Counsel No. 58
(44 FR 39508) dated March 29,1977
(pGG#58):
.*'•*- * Rather than downgrading the
standard [note: downgrading the standard is
currently referred to as removing a
designated use in EPA's Water Quality
Standards Regulation at 40 CFR 131.10(g)j for
an entire stream, or stream segment, some .
States have maintained the standard, but
provided that individual dischargers may
receive variances for a limited time period
from meeting standards. This approach
appears to be preferable environmentally.
The more stringent standard is maintained
and is binding upon all other dischargers on
the stream or stream segment. Even the -
discharger who is given a variance for one ;
particular constituent * * * will be required \
to meet.the applicable criteria for other
constituents. T}ie variance is given for a
limited time period and the discharger must
either meet the standard upon the expiration
of this time period or must make a new ' ,
demonstration of unattainability.
EPA will accept such variance procedures
as part of State water quality standards as
.long as they are consistent with the
substantive requirements of 40 C.F.R, 130.17
[note: 40 CFR 130.17, as revised on
November 8,1983; is currently codified as
Water Quality Standards at 40 CFR 131].
Therefore, variances can be granted by States
only when achieving the standard is
unattainable. In demonstrating that meeting"
the. standard is unattainable, tie State must
demonstrate that treatment in excess of that
required pursuant to section 3.0i(b)(2) (A)
and (B) of the CWA is necessary to meet the ,
standard and also must demonstrate that
requiring such treatment will result in
substantial and widespread economic and .
social impact * * *.
The justification submitted by the State
should include documentation that treatment
more advanced than that required by section
303(c)(2)(A) and (B) has been carefully
considered and that alternative effluent
control strategies have been evaluated.
Since State variance proceedings involve
revisions of water quality standards, they
must be subjected to public notice, :
opportunity for comment, and public
hearing. (See section 303(c)(l) and 40 C.F.R.
130.17(a)0 The public notice should contain
a clear description of the impact of the
variance upon achieving water quality
standards in the affected stream segment.
OGC #58 has formed the basis for .
EPA's water Duality standards variance
policy to the present. This decision is ,
available in the administrative record
for this rulemaking.
Subsequent guidance has elaborated
on or clarified the policy over the years.
For example, the Director of EPA's
Criteria and Standards Division, '
transmitted EPA's definition of a water
quality standards variance to the
Regional Water Quality Standard
Coordinators on July 3,1979 (1979
Guidance), which is available in the
administrative record for this
.rulemaking, variances are granted for a
specific period of time and must be
rejustified upon expiration but at least
every three years. The three-year
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
Trustification is derived from the
triennial review requirements of section
303fc)oftheCWA.
The 1983 revisions of the Water
Quality Standards Regulation allowed
States to include variances in State
standards, subject to EPA review and
approval (40 CFR 131.13). In the
preamble discussion of the General
Policies Section (1983 Preamble at 48
FR 51403), EPA re-affirmed the
allowability of State water quality
standards variances mirroring the
requirements as set out in OGC #58:
EPA has approvod Stato-adoptod variances
in the past and will continue to do so if: each
individual variance is included as part of the
witor quality standard * * * and is granted
bajod on « demonstration that meeting the
standard would causa widespread social and
economic impact, the same test as if the State
wore changing « use based on widespread
social and economic impact * * * With the
varianco provision, NPDES permits may be
written such that reasonable progress is made
toward attaining the standards without
violating section 402{a)(l) of the CWA which
states that NPDES permits must meet the
applicable water quality standards.
The 1983 preamble noted that water
quality standards variances were
appropriate for granting relief to NPDES
discharge permits and linked the
granting of such variances to reasonable
progress being made toward meeting the
underlying standards.
In December 1983, EPA produced a
Handbook to assist in implementing the
1983 Regulation. The Handbook
explains that in showing widespread
social and economic impact, the
determining factor is whether the
impact on the discharger is sufficient to
have a substantial and widespread
impact on the affected community and
not just on the discharger.
On March 15,1985, the Director of the
Office of Water Regulations and
Standards, responding to questions
raised on water quality standards
variances, issuea a reinterpretation of
the factors that could be considered
when granting variances (1985
Guidance). This memorandum
explained that variances could be based
on any of the grounds outlined in 40
CFR 131.10{g) for removing a designated
usa, not merely on the widespread
social and economic impact ground.
This interpretation was based on the
fact that, under section 510 of the Clean
Water Act, States have the right to
establish more stringent standards than
thcsa suggested by EPA. Therefore, as
long as any temporary water quality
standards variance conforms to the
requirements established in 40 CFR
131.13fg) for removal of a designated
uso, it would be more stringent than the
Federal requirements since it would be
a temporary rather than permanent
change.
2. GLWQI Proposal (40 CFR Part 132,
Appendix F, Procedure 2)
The proposed Great Lakes Guidance,
procedure 2 of appendix F of part 132,
proposes a procedure to ensure
consistent application of water quality
standards variances for, the Great Lakes
States and Tribes. Variances can be
requested for any of the grounds which
justify removing designated uses set out
at 40 CFR 131.10(g).
, The six conditions set forth in
proposed procedure 2.C.1 through 2.C.6
of appendix F are, as discussed above,
taken from 40 CFR 131.10(g) and are
generally self explanatory. EPA has not
provided further details or definition for
these six conditions for that reason and
because it could interfere with lie
intention to give the States and Tribes
some latitude in applying this provision
on a case-by-case basis. However, £PA
solicits comments on whether
procedure 2.C.3 of appendix F should
be clarified to prevent any bootstrapping
by parties who have contributed to the
human-caused conditions or sources of
pollution. That is, should parties that
have contributed to conditions that
prevent water quality standards from
being attained be explicitly prohibited
from being granted a water quality
standards variance based on that non-
attainment? An example of such .
bootstrapping might be a discharger,
whose past or present activities
(including, but not limited to,
discharges, spills, or leaching of
pollutants) have contaminated
sediments which currently cause non-
attainment of water quality standards,
requesting a water quality standards
variance based on that previous and/or
continuing, pollution.
As mentioned in the discussion on
pollutants in intake waters (section
VHI.E of the preamble), variances may
be available under procedure 2.C.6 of
appendix F for certain dischargers
where the intake water contains a
ubiquitous pollutant which is found in
almost all water bodies in a watershed
at about the same concentration due to
watershed-wide contributions from
nonpoint sources and where removing
the pollutant would cause a substantial
and widespread social and economic
impact. In the case of small dischargers
unable to meet the widespread social
and economic impact test, a variance
may be available under procedure 2.C.3
of appendix F, which applies where
there are human caused conditions or
sources of p dilution that cannot be
remedied, at least in the near term. In
either case, the variance would establish
an interim criterion for the pollutant
that accounts for the background level
and the level of incidental removal
obtained by the discharger's proposed or
existing treatment system. EPA seeks
comment on whether such variances
addressing ubiquitous pbllutants'should
be available to new as well as_ existing
dischargers. Comments are also solicited
on whether this, or any of the other six
conditions for granting a water quality
standards variance, require further
explanation or clarification.
The proposed Guidance would not
require the Great Lakes States or Tribes
to have a variance procedure for water
quality standards, but if they adopt one,
it would be required to be consistent
with the procedure proposed herein. In
the proposed Guidance, Great Lakes
States and Tribes would retain the ,
discretion to define what specific
information they will require in a
permittee's variance demonstration and
application pursuant to procedures 2.C
and 2.D of appendix F. Great Lakes
States and'Tribes would also have the
discretion to define the decision criteria
the Great Lakes State or Tribe will use
when approving or disapproving a
variance under procedure 2.F of
appendix F, as long as they are at least
as stringent as the requirements
proposed in procedure 2.C, subject to .
EPA review and approval.
A Great Lakes State or Tribe choosing
to adopt variance procedures will
provide information, pursuant to part
132.5(b)(3) of the proposed Guidance,
on the requirements for the variance
demonstration and application as well
as the evaluation criteria that the State
or Tribe would use to approve or
disapprove specific variances. This will
assure that: the public has sufficient
information to comment on the
appropriateness of a State's or Tribe's
WQS variance process pursuant to part
132.5(c) of the proposed Guidance; EPA
has sufficient details to determine if the
State or Tribe procedures comply with
the CWA and are.approvable pursuant
to part 132.5(d) of the proposed
Guidance; and both EPA and the public
have adequate information on which to
judge State or Tribal compliance with
its own procedures when making
individual variance decisions. EPA
requests comment on whether the
appropriate amount of latitude is given
the States and Tribes and on whether it
will provide for the consistency within
and between State and Tribal programs
in the Great Lakes System that the .
proposed Guidance is intended to
provide. Neither the procedure
proposed, nor any State or Tribal
procedures adopted consistent with it, ,
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Federal Register / Vol. 58, Np, 72 / Friday, April 16, 19.93-/ Proposed"Rules^ . 20923
would require States, or Tribes to grant
variances in any specific circumstance.
EPA requests comment on whether
this section provides adequate guidance,
and sufficient detail, for the Great Lakes'.
States and Tribes to make appropriate
decisions on water quality standards
variance applications. ... .
3. Applicability . . ;
The Guidance requkes variances
apply only to the permittee requesting
the variance and only to the pollutant(s)
specified. The water quality standards
,. for the affected water body are not
otherwise changed by a water quality
standards variance. Although a variance
modifies specific criteria for specific
NPDES discharges, the underlying water
quality standards for the water body
.have full force and effect for all other
purposes, and any controls place)d on
other sources of pollution to the water
body should be designed to meet those
standards. Any TMDL/WLA/LA, NPDES
permit (other than the specific one
modified pursuant to the variance), or v
other water pollution control
requirement is to be implemented in a
manner consistent .with the appropriate
implementation absent the variance.
. The proposed Guidance would not
allow variances for new or
recommencing dischargers as those
terms are defined at 40 CFR 122,2.
Water quality standards variances are
intended to provide relief, whera
appropriate, to existing dischargers.
Variances could apply to existing
dischargers even where water qiiality
standards have been on the books for a
while (as long as they have consistently
not been attained). New and . .
recommencing dischargers should
design their facilities and treatment to
meet water quality standards. EPA
requests comment on the .
. appropriateness of these restrictions and
on whether variance requirements for
increasing dischargers should be
different from those for existing
dischargers as those terms are defined at
procedure 9.D of appendix F of the
proposed Guidance and whether the
definition for new discharge at . ...
procedure 9.D of appendix F of the
proposed Guidance is-more appropriate
to this section than the definition at 40
CFR 122.2.
4. Maximum Timeframe
The Great Lakes Guidance proposes a
maximum three-year limit on the,
duration of variances, subject to
possible renewal. This is intended to
reinforce the triennial review required /
of all water quality standards in section
303(c) of the Clean Water Act EPA's
1979 Guidance clearly indicated that
variances must be reviewed ©very three
years! Some States and Tribes use the
triennial review process to accomplish
this review, however, this is not
universal and triennial reviews are often
delayed. EPA believes that the most
effective way to assure that variances get
a detailed review at the prescribed
interval is to require them to actually
expire at no greater than three-year i .
intervals. -
5. Conditions to Grant a Variance
Variances under the Great Lakes
Guidance are applicable if any of five
specified types of water body conditions
exist and/or the affected community
would encounter substantial and
widespread economic and social
impacts as aresult of the point source
having to install controls beyond
technology-based requirements. The
permittee must also make two other
demonstrations^ -.-..•
The first demonstration would be that
the requested variance is consistent
with State or Tribal antidegradatibn '
procedures. This requirement would
prevent a variance that would result in
a lowering of actual water quality for .
any pollutant where water quality for
that pollutant does not support either,
-the designated or existing uses or in any
water constituting an outstanding
national resource as proposed at section
I.C of appendix E of part-132. This
provision would also prevent
dischargers from avoiding the proposed
requirements of section I.B of appendix
E of part 132 in high quality waters by
requesting a variance rather than
conducting an antidegradation
.demonstration. In most instances,
variances are requested where water
quality standards are already not being
met. In addition, the requirement at
procedure 2.F.1 of appendix F requiring
dischargers to maintain the level of.
treatment achieved under the previous
permit would normally prevent a
discharger from being granted a variance
that would result in a lowering of water
quality. The antidegradation showing
would simply demonstrate to the State
and public that either a concurrent
antidegradation question is not at issue
or that, if one is, the regulatory
provisions for antidegradation are being
- met. EPA requests comment on whether
this demonstration is appropriate. _-.•:
Second, the applicant would be
required to demonstrate the extent of
any increased risk to human health and
the environment associated with
compliance with the variance compared
to the.original water quality standards,
and the State or Tribe would be required
to find that any such increased risk is
consistent with the protection of the
public health, safety and welfare before
granting a variance. Because variances,
are from water quality standards that
meet the goals and requirements of the
Clean Water Act, this language is
intended to ensure that the "general
requirement of section 303(c)(2)(A) of
'the CWA (i.e., such standards shall be
such as to protect the public health and
welfare) is met even though specific
protective criteria may be temporarily •
exceeded. .
The permittee has the sole
responsibility to provide sufficient
relevant information, pursuant to State
or Tribal requirements, to make a
variance demonstration for the
pollutant(s) in question. Failure of the
permittee to make the demonstration or.
to provide sufficient information in the
submitted demonstration shall result in ,
a State denial of the variance,
6. Timeframe to Submit Application.',,-.
The proposed Guidance would allow .-.
initiation of the source-specific variance
process after the controls based upon
water quality standards are imposed in
NPDES permits since that is the time ,K
when a point source discharger knows**^
the exact requirements'that will be
imposed and is in the best position to
assess whether those limits can be
attained. This would reduce the number
of variance requests by avoiding
protecting requests, Commentis
requested on whether it'-would be more
appropriate to require Initiation of the : .
variance process within 60 days of a
proposed permit. If a variance is granted
after the effective date of the water ,.
quality-based NPDES effluent limitation
in question (e.g., after completion of any
evidentiary hearing during which the
limitation was stayed and after the
compliance date for the limitation), then
the permittee willhave to demonstrate
satisfaction of the ahti-backsliding ,
requirements of section 402 (o) of the
CWA before the permit can be modified
to include a less stringent effluent
limitation. That demonstration may be
based on either section 402(p) or section
303CDX4XA). :,
7. Public Notice of PreUminary Decision
The proposed Guidance would
provide the public an opportunity to be
involved at two times: First, during the
comment period associated with the
notice of receipt, of the variance request;,
and second,",during the public notice of
the modification of the permit. In ,
addition, the requirement that variances
be appended to State water quality
standards rules ensures that the public
is made aware of which variances have
been granted. Both public notices
should contain a clear, description of the
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
impact of the variance upon achieving
water quality standards in the affected
stream segment.
Tha following is a summary of the
elements that EPA would expect to he
made available to the public in order to
moot the public notification
requirements of the water quality
standards regulation and the proposed
Guidance. These items would not need
US be included in detail in the public
notice; however, the public must be
mado aware of their existence and of
how and where they may be obtained.
a. A statement that the action must
comply with the State's or Tribe's
variance procedures and description of
those procedures.
b. The permittee's demonstration,
Including the rationale for the requested
variance and the extent of any increased
risk to human health and-the
environment associated with the
variance.
c. In addition, for the public notice for
the modification of the NPDES permit,
the public comments and public hearing
record pursuant to procedure 2.E of
appendix F, and the State approval
pursuant to procedure 2.F appendix F of
thoproposed Guidance.
EPA requests comment on whether
the public notice requirements in this
proposal are adequate to allow the
public to be fully involved in the State
wafer quality standards variance process
and, if not, what requirements would be
adequate.
8, Final Decision on Variance Request
The proposed Guidance would allow
the State's or Tribe's final decision on
tha variance request to be an approval,
all NPDES permit conditions needed to
implement the parts of the variance
approved. These conditions would be
designed to assure that; The permittee
minimizes, to the maximum extent
possible, exceedance of the underlying
water quality standards by
implementing the level of treatment
currently achievable (conditions
requiring effluent limitations at least as
stringent as those achieved under the
previous permit); the permittee makes
reasonable progress toward attaining the
water quality standards as envisioned in
tha 1983 preamble, through appropriate
conditions (such as the establishment of
a capital improvements fund and
continued investigations of treatment
technologies, process changes, pollution
prevention, wastewater reuse and/or
other techniques that will reduce the
lovel of the pollutant or result in
compliance oy the permittee with the
WQS and submission of reports on the
investigations at such time specified by
the State), and effluent Limits sufficient
to protect water quality standards are in
effect upon expiration of the variance.
9. Incorporating State- or Tribal-
Approved Variance Into Permit
Once the variance is granted, the
appropriate NPDES permitting authority
would be required to modify the NPDES
permit to incorporate all NPDES permit
conditions determined to be necessary
to implement the variance. „
10. Renewal of Variance
The proposed Guidance would
require the permittee to apply for a
variance renewal and make a new
showing of justification, no later than
the required submission of a permit
application for a NPDES permit, or 60
days prior to the expiration of the
variance, whichever occurs earliest;
variances would not be automatically
renewed. As part of the renewal
application, the permittee must be
required to demonstrate that it has met
the NPDES permit conditions
implementing the existing variance. The
same public notice requirements for the
initial issuance of a variance would
apply to the renewal. Permittees not
demonstrating compliance with these
conditions would not be eligible for
variance renewal. EPA requests
comment on the sufficiency of the
proposed renewal requirements.
11. EPA Approval
Variances are modifications of State
or Tribal water quality standards and
are, therefore, subject to EPA review and
approval. Like other water quality
standards changes, variances are
effective when adopted (under the terms
of the adoption), whether or not EPA
review is complete. For EPA to conduct
an adequate review, sufficient
information must be submitted.
Procedure 2.1 of appendix F would set
out the timeframe and substantive
requirements for that submittal. EPA's
review would follow the procedures of
40 CFR 123.44 and 40 CFR 131.21. EPA
requests comment on the sufficiency of
the proposed information requirements
in this section as well as the
appropriateness of the proposed
timeframes.
12. State or Tribal Water Quality
Standards Revisions
Because water quality standards
variances are modifications of water
quality standards, the proposed
Guidance would require the State or
Tribe to append the State- or Tribal-
approved variances to the State's water
quality standards. EPA has traditionally
required water quality standards
variances to be granted through the
water quality standards adoption
process. This requirement is intended to
ensure that: the public is made aware
that a water quality standards change is
under consideration and has sufficient
opportunity to comment on the action;
the State or Tribal water quality
standards document accurately reflects
the criteria that •will be used to derive
effluent limitations and other water
quality-based controls; and water
quality standards variances are
submitted to EPA for .review and
approval/disapproval under section 303
oftheCWA.
There was considerable concern
expressed by the States,, during the
preparation of the proposed Guidance,
that this requirement would make water
quality standards variance adoptions so
lengthy that variances would be
essentially unusable for granting
appropriate relief to dischargers in a
timely manner. EPA and the Technical
Work Group recognized this concern
and have, through the public,.
participation and EPA review and
approval requirements of the proposed
Guidance, met the substantive
requirements of a water quality
standards action while allowing a water
quality standards variance be appended
to, rather than adopted in, the State or
Tribal standards. Thus, the proposed
Guidance allows the Great Lakes States
or Tribes to grant water quality
standards variances without requiring
that those variances go through their
usual water quality standards adoption
process. EPA requests comment on
whether the proposed Guidance
adequately meets the intent and
substantive requirements for State or
Tribal adoption of variances as changes
to water quality standards.
The proposed Guidance contains no .
timeframe under which the State and
Tribes would be required to append the
variance to the standards. EPA requests
comment on whether such a mandatory
timeframe is necessary, and if so, what
that timeframe should be.
13. Consistency With the CWA and
Confdrmance With the GLWQA
The CPA requires EPA to develop,
inter alia, guidance on procedures that
States must use to implement the
Guidance's water quality criteria in tha
Great Lakes System. The CPA states that
the proposed Guidance shall be no less
restrictive than the provisions of the
Clean Water Act, and shall conform
with the objectives and provisions of the
Great Lakes Water Quality Agreement.
The variance provision contained in the
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Federal Register /Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
20925
proposed Guidance complies with these
requirements, as explained below.
a. Consistency With the Clean Water
Act. It is the goal of the Clean Water Act
to achieve, wherever attainable, water,
quality which provides for the
protection and propagation of fish,
shellfish, and wildlife and provides for
recreation in and on the water.-33 U.S.C.
1251(2). EPA's regulation found at 40
CFR 13l.lb(g) addresses the above
language's phrase wherever attainable.
To fully understand the proposed
•Guidance on water quality standards
.variances, one must start with this
provision. Basically, under the CWA's
regulatory structure, water quality
criteria are set by States or Tribes at
levels which are directed at achieving a
stream's designated use(s). 40 CFR
131.10(g) sets forth the procedure by
which States or Tribes may remove a
stream's designated beneficialjise,
under specified conditions. Removing a
. stream's designated use due to the
unattainability of that use may have the
effect of lowering the water quality
criteria for the subject stream segment
unless a use with more'stringent criteria
is designated. - ,
. Limiting the applications of 40 CFR
131.10(g) is 40 CFR 131.10(h), which
states:'
States may not remove designated
uses if: .
(1) They are existing uses (existing uses are
those uses actually attained in the water body
on or after November 28,1975, whether or
not they are included in the water quality
standards. 40 CFR 131.3(e).), as denned in
§-13li3, [i,e.,] unless ause requiring more
stringent criteria is added; or
(2) Such uses will be attained by
implementing effluent limits required under
sections 301ft) and 306 of the CWA and by
implementing cost-effective and reasonable
best management practices for nonpoint
source control. '• .
The practical effect of removing a ,
stream's designated use is that the' water
quality criteria (which are the bases for
limiting the discharge of pollutants into
that stream) are revised to meet the
remaining or revised use(s). Removing
or modifying i beneficial use, therefore,
may effect a relatively widespread and
permanent lowering in waiter quality ,
criteria. , . ' - V ' '
: No use removal provision exists in the
proposed Guidance because, in general,
, permanent removal of CWA goal uses
would have little or no effect on the
applicable water quality criteria,
Instead, as explained in sections III, V
and VI of this preamble^ water quality
criteria or methodologies for the
protection of aquatic life, wildlife and
human health are applicable basin- ;...
wide, with limited exceptions (see
section VIII. A on site-specific
modifications).
In effect, the variance provision
included in the proposed Guidance, in
addition to providing the variance ,
function provided for in 40 CFR 131,
provides a method, appropriate to the
Great Lakes, analogous to the Federal
use removal provision. Consistent with
this approach, the proposed Guidance
basically incorporates the language from
40 GER 131.10(g), with minor
modifications. The difference, of course,
as mentioned previously in the
preamble discussion, is that the
application of the factors in the
proposed Guidance will only result in a
temporary variance for individual
dischargers and pollutants rather than •
resulting in a removal or modification of
'a designated use and possible change of
associated criteria'for the. entire water
body segment. For this reason and
viewed in context, therefore, the
proposed Guidance is not less stringent
than what the CWA currently allows. -
Secondly, it will be recalled that the
Water Quality Standards Regulation (40
CFR Part 131) does not require, but only
indicates the allowability of, State or
Tribal variance procedures. The
proposed Guidance is consistent with
this approach because the proposed
Guidance does not require a State or,
Tribe to have variance procedures, but ,
rather only specifies what the variance
provision should be consistent with if
the State or Tribe decides to adopt one.
Finally, as outlined previously in the
preamble discussion, the proposed -
Guidance is fully consistent with the
EPA's prior opinions and guidance , .
documents on State variance provisions.
(e.g., the Decision of the General •
Counsel No. 58 dated March 29,1977;
Preamble to the 1983 Revisions to .the
Water Quality Standards Regulation;
and the 1985 Guidance on Variances . --_"'
issued by the Director of the Office of
Water Regulations and Standards,
which is available in the administrative
record for this rulemaking.)
b. Gonformance With the'Great Lakes
Water Quality Agreement. Like the
Clean Water Act, the purpose of the .
Great Lakes Water Quality Agreement
(GLWQA) is to restore and maintain the
chemical, physical and biological
integrity of the waters it addresses. "
Similar to the Clean Water Act, the
Agreement is structured to achieve this
purpose by requiring the elimination or
reduction to the maximum extent
practicable of discharges of pollutants :
into the Great Lakes System. See Article
H, Purpose. .•••--.. ;
As indicated by the language, to the
maximum extent practicable, the
•GLWQA recognizes the need for
flexibility In addressing requirements
which, if imposed, would be
impracticable. In particular, the
Agreement contains language in Article
TV, Specific Objectives, which explicitly
recognizes situations in which
achievement of Specific Objectives
.cannot be attained. These provisions are
reasonably read as delineating situations
in which temporary variances are
permissible. Article IV, Specific •'-'"'
Objective 1, contains the following •
provisions: .
(e) The Parties recognize that in certain ,
areas of inshore waters natural phenomena
existiwhich, despite the.best efforts of the
•Parties, will prevent the achievement of some
of the Specific Objectives; As early as
possible, these areas should be identified
explicitly by the appropriate jurisdictions ;
and reported to the International Joint
Commission.. .
: (f) The Parties recognize that there are .
areas in the boundary waters of the Great
Lakes System where, due to human activity, •
one or more of the General or Specific
Objectives of the Agreement are not being <"
met. Pending virtual elimination of the
persistent toxic substances in the Great Lakes
System, the Parties, in cooperation with State
and Provincial Governments and the
Commission, shall identify and work toward
the elimination of: .
(i) Areas of Concern pursuant to Annex 2;
•and . . :• - ,
• (ii) Critical Pollutants pursuant to Annex 2;
and . . ..'••'"•.
(iii) Point Source Impact Zones pursuant tb
Annex 2. '•••••'
These provisions clearly recognize
that objectives may not be attainable
due to natural phenomena and/or
human-caused conditions. In the case of
an area affected by natural phenomena, .
the Agreement requires such areas to be
identified and reported to the
international Joint Commission! In the
case of areas affected by human activity,
the Agreement requires the Parties work
toward elimination of such conditions
areas by identifying and eliminating
Areas of Concern, Critical Pollutants
and Point Source Impact Zones,
The provisions of Article IV as wellas
the practicable language in Article II of "'
the Agreement, are reasonably read as
allowing provision for temporary
variances from water quality standards.
The variance provision in the proposed
Guidance specifies certain naturally
occurring and human-caused sources of
pollution which could justify temporary
relief from standards. The widespread ;
social or economic impact variance •'.-'•
addresses the Agreement's language that
discharges must be reduced or
eliminated where-practicable.
It is EPA's position that the.variance ,
provision included herein conforms-
with the GLWQA because it is limited ';
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20926 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
to situations where the discharger's or
the stream's compliance with water
quality standards is not practicable.
Additionally, the proposed Guidance
requires that reasonable progress be
made toward compliance with water
quality standards. This requirement
parallels the requirement of Article IV(f)
of tho GLWQA, that the Parties must
work toward the elimination of the
sources of pollution in the areas not
complying with the objective of the
GLWQA,
14. Options Considered
«. One option considered by the
Technical Work Group when
developing the proposed Guidance
would nave: allowed the State or Tribe
to request additional information from
tho permittee within 30 days after
receiving the variance application and
given the permittee an additional 30 '
days to provide the additional
Information; required the Great Lakes
State or Tribe to issue the preliminary
decision on the variance request within
' 120 days of receipt of the completed
application and provide a 30 day public
comment period on the preliminary
decision, and; required the State or
Tribe to issue a final decision within 90
days of the expiration of the public
comment period or the receipt of
additional information discussed above.
Failure of the permittee to provide the
additional information in the time
allotted would have resulted in the
denial of the variance. The proposed
Guidance does not contain these time
constraints because it is EPA's opinion
that existing State or Tribal
administrative procedures provide both
sufficient freedom to request additional
information and sufficient requirements
to act in a timely manner.
EPA requests comment on whether
the proposed Guidance requires the
Great Lakes State or Tribe to act in a
. sufficiently timely manner on variance
applications or whether time constraints
similar to the above are necessary. EPA
also requests comment on whether the
proposed Guidance allows the State or
Tribe sufficient flexibility in collecting
the information necessary to make a
defensible decision or whether an
explicit period for requesting additional
information is advisable.
b. Another option considered by the
Technical Work Group would require
NPDES permitting authority to initiate
any applicable NPDES permit
modification in procedure 2.G of
appendix F, of the Guidance within 60
days aftei granting the variance. The
proposed Guidance does not contain
this lima constraint because it is EPA's
opinion that existing State or Tribal
administrative procedures provide
sufficient requirements to act in a timely
manner.
EPA requests comment on whether
the proposed Guidance requires
sufficiently timely State or Tribal action
in initiating a permit modification in
response to an approved water quality
standards variance.
c. Another option considered by the
Technical Work Group allowed
variances based only on procedure 2.C.6
of appendix F, widespread social and ,
economic impact. EPA chose to expand
the allowable bases for water quality
- standards variances to include those in
procedures 2.C.1 through C.5 of
appendix F, where water body
conditions may warrant short-term relief
for point sources to be consistent with
EPA's 1985 Guidance and section 510 of
the CWA. In addition, EPA found that
these additional bases for a water
quality standards variance, especially
procedures 2.C.1 and 2.C.3 of appendix
F, were necessary to provide States with
sufficient flexibility to address the issue
of unreasonable water quality-based
effluent limits resulting from ubiquitous
pollutants in a facility's intake water
(see discussion hi section VIII.E of this
preamble.)
EPA requests comment on whether
the factors for the granting of variances
to water bodies in the Great Lakes
System should be different than those
for granting variances in other waters of
the United States and, if so, the
scientific rationale for such a difference
(see also section o.ii, below), EPA also
seeks comment on whether the
requirements under procedure 2.C of
appendix F that cost-effective and
reasonable best management practices
for nonpoint source control be
implemented should, as proposed, be
limited to best management practices
the permittee can implement or should
include all best management practices
required by a State or Tribal regulatory
program for the area in question.
d. Another option considered by the
Technical Work Group required the
State or Tribe to provide for an
additional period of public comment.
This public comment period would
have been initiated within 30 days of
receipt of a completed variance
application and would have given the
State public input prior to making a
preliminary decision on a variance
request. EPA has not included this
additional public comment period in
the proposed Guidance because two
opportunities for public comment are
provided, first, during the comment
period associated with the notice of
receipt of the variance application, and
second, during the public notice of the
modification of the permit, and because
an additional comment period was
considered to be unnecessary and pose
an undue administrative burden on the
States^
EPA requests comment on whether
there is a need for public comment early,
in the variance process and, if so, how
that need can be met without posing an
undue administrative burden on the
State and Tribal governments.
e. Another option considered by the
Technical Work Group, would have
required States and Tribes to public
notice variance applications in all eight
Great Lakes States. The proposed
Guidance requires the Great Lakes
States and Tribes to notify the other
Great Lakes States and Tribes of the
preliminary decision. EPA decided
against proposing to require the wider
public notice requirement because it
was considered to be unnecessary, to
pose an undue administrative burden on
the States and to have the potential to
unreasonably lengthen the variance
review and approval process.
EPA requests comment on whether
wider public notice is necessary and, if
so, how it can be accomplished without
posing an undue administrative burden
on the States and without having the
potential to unreasonably lengthen the
variance review and approval process.
15. Request for Comments
EPA specifically invites public
comment on these additional issues that
received discussion during the drafting
of this proposal:
a. Although the proposed Guidance
emphasizes that variances are based on
water quality standards, these variances
are implemented for point sources in
the permitting process. The three-year,
expiration of water quality standards
variances is based on-the triennial water
quality standards review cycle and
makes sense for a provision that
requires a modification of standards.
However, NPDES and State- or Tribally-
authorized permits are normally granted
for five years. Because the variance •
would be implemented in a permit, it
has been suggested that the variance
requirements include a provision,
allowing variances to be granted for up
to five years, with a reassessment after
three years. EPA invites comment on
this suggestion.
b. Some States have suggested using
criteria similar to the first five elements
(procedures 2.C.1 through 2.C.5 of
appendix F of part 132) to establishing
variances to use classifications for entire
water body segments or portions of
water body segments. This could be
done, for example, where historic
mining practices have impaired water ,
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Federal Register./-' Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
quality and designated uses, but the ,
State 01 Tribe has considered the,
problems correctable within a
reasonable planning period (the 20-year,
section 208 planning period, for . ;
example). In such situations, the State ,
maintains goal uses and underlying
criteria while recognizing existing
ambient conditions by adopting
ambient-based criteria which ha,ve
specific expiration dates. This approach
allows a State or Tribe to incorporate
the criteria modified by the water body
variance into all appropriate.NPDES
permits on the specific water body. This
approach might be used to relieve :-
dischargers from the burden of . .
demonstrating that individual variances
are appropriate and allows multiple
dischargers to pool their resources to ,
make a demonstration that a variance
based solely on water body conditions
is appropriate. This approach might also
decrease the State or Tribal burden of,
reviewing multiple applications for
discharger-specific variances based on
water body conditions.
EPA believes that the water body
variance may provide a way of applying
the use-based 40 CFRl31.10(g)
elements in a manner that makes sense
and meets the objectives of the water
quality standards variance policy. EPA
requests comment on this bifurcated
approach of dividing variances into two
categories: water body variances to .
which the first five elements
(procedures 2.C.1 through 2.C.5 of
appendix F) apply, and discharger-
specific variances to which the
'. substantial and widespread economic
and social impact element (procedure
2.C.6 of appendix F) applies.
EPA additionally requests comment,
pn whether it would be appropriate to
require, as a condition to granting the
water body variance referenced above,
that a TMDL be developed for the water
body at issue based, on pre-variance
criteria. See section VHI.C on TMDLs,
. especially phased TMDLs at section
VII!.C.2.b, for further information on .
what this requirement would entail. The
rationale for conditioning a water body
, variance with the TMDL requirement is
that, before all dischargers are given
relief from applicable water quality
standards, there should be a plan in
"place through the TMDL process to
ultimately achieve the applicable water
quality standards. EPA also requests
comment on the maximum tirneframe
for completing such a required TMDL if
one should be required. For example,
. making a water body variance non-
renewable would have the effect of
requiring a TMDL be developed within
three years (or by the expiration of the
variance). Permits could then be written
to be in.conformance with the TMDL
and a variance would no longer be
•necessary. ;
c. Because variances may not be :
granted if they do not comply with the
proposed Antidegradation Policy at 40
•CFR 132, appendix E, a variance will
not be allowed if it results in lowering
of existing water quality unless in
compliance with the antidegradatiqn •-
requirements. Because of this
restriction, because variances are subject
to EPA review, and because EPA will.
consult with the Fish and Wildlife
: Service regarding approvals of water
quality standards pursuant to a recently
signed agreement, it does not appear
that variances would be granted which
would jeopardize threatened or
endangered species. EPA requests
comments on whether additional
safeguards are needed to protect -
threatened or endangered species.
d. Procedure 2.C.6 of appendix F
allows a water quality standards
, variance to be granted if controls would
cause widespread social or economic
impact, EPA has traditionally used
many of the same ecoridmic measures to,
determine social or economic impact
when evaluating use removal and water
quality standards variance requests as it-
uses to determine important economic
or social development when evaluating
the allowable lowering of water quality
• under the antidegradation policy. EPA
requests comment on whether further
guidance on how to determine social or
economic impact is needed, and, if so,
whether social or economic impact.
should be interpreted similarly to
important economic or social
development as discussed in section '_
VII.F. 5 of this preamble
(Antidegradation Demonstration). EPA
also requests comment on whether
further guidance is necessary on the
interpretation of widespread, and, if so,
whether the determination of
widespread should be similar to the
determination of economic area
discussed in section VII.F.5 of this
preamble (Antidegradation
Demonstration),
e. As written, the variance provision
-- only provides for variances for
applicants for NPDES permits, not
section 404 permits for the discharge of
dredged or fill material. As a practical
matter, few if any section 404 .
dischargers would be eligible for a water
quality standards variance, as . :
envisioned in the proposed Guidance,
, because most section 404 discharges are
short-term, one-shot activities and'
therefore the applicants would be new
dischargers or recommencing
dischargers. EPA solicits comments on
-whether there is any rifeed to expand the
proposed variance procedure'to address
non-NPDES permits.
C. Totdl'Maximum Daily Loads
I/Background .
'. One approach to achieving the water
quality goals of the Glean Water Act is
to ensure that technology-based effluent
. limitations are established in NPDES
permits. Such limitations are based on:
(1) Effluent guidelines established by
EPA for major industrial categories
under section 304 of the Clean Water
Act, (2) the best professional judgement
of permit writers for industrial point
sour'ces not subject to effluent
guidelines or, (3) secondary treatment
requirements for POTWs. Where "
existing technology-based limitations, '
together with other State or Federal
pollution controls are insufficient to
attain and maintain water quality: .
standards, additional water quality-
based controls are necessary. Section
303(d) of the Clean Water Act requires
the establishment of total maximum
daily loads (TMDLs) for waters that are "
not expected to meet-applicable State
water quality standards despite •.-."
implementation of existing or planned
pollution controls. . .
2. National Approach •
a. General Approach to TMLIL
Development. EPA National policy on
theldevelopment, review and approval
of TMDLs is contained in the Water
Quality Planning and Management
regulation, 40 CFR part 130. Additional
guidance is provided in the "Technical
Support Document for Water Quality-
based Toxic Control," (TSD) EPA,505/
2-90-001, March 1991 and the :
"Guidance for Water Quality-based'
Decisions: The TMDL Process/'.EPA
440/1-91-001, April 1991.
TMDLs are established to meet the
water quality criteria and designated
uses that apply to a given water body.
The TMDL quantifies the maximum ,
allowable loading of a pollutant to a
water body, and allocates this loading
capacity to contributing point and
.nonpoint sources (including natural
background) such that water quality
standards will not be violated. A TMDL
must incorporate a margin of safety
(MOS) that accounts for Uncertainty
about the relationship between
pollutant loads and water quality.
TMDLs may. involve a single pollutant
source or multiple sources (e.g., point
sources and nonpoint sources) and may
be established for geographic areas that
•range in size from large watersheds to
, relatively small water body segments.
EPA encourages the development of
TMDLs that reflect tradeoffs betvy een
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
point and nonpoint sources where such
tradeoffs achieve the desired .
environmental result and are cost-
efficient,
EPA guidance suggests that protective
assumptions be used in developing
TMDLs and recognizes that use of such
conservative assumptions may provide
Uw MQS required. Where necessary, an
additional margin of safety can be
allocated as a separate component of the
TMDL.
b. Phased TMDLs, The CWA assigns
' th« primary role for TMDL development
to the States and the Indian Tribes. EPA
, provides guidance to the States and
Tribes and is required to review TMDLs
the States and Tribes develop. If EPA
disapproves a State or Tribal TMDL, the
Act authorizes EPA to establish a
revised TMDL,
Gflntrally, a phased approach to
* TMDL development should be used
when significant nonpoint source or
complex water quality problems
involving many sources are present.
Under a phased approach, a TMDL is
davaloped and implemented using best
availftblo information, professional
Judgement and a margin of safety that
it fl*cts uncertainties. The phased
TMDL Incorporates a monitoring plan
and a schedule for assessing the
a'tainiaent of standards after the
ImplemtrataUoa of pollution controls. If
standard* are not attained after
implementation of the TMDL, the data
obtained through the monitoring
program can be used to develop a
revised TMDL.
TMDLs established using the phased
approach allow EPA and the States to
move forward and implement water
quality-based control measures when
limited information is available. Thus,
for example, TMDLs that address
pollutants originating primarily from
nonpoint sources can be established
using the phased approach even though
tho ability to analyze and model
nonpoint source loadings, pollutant fate
and transport and actual water quality
effects is not as developed as the ability
for point source loadings. Under the
phased approach the statutory
requirements of section 303 (d) can be
met even in the absence of extensive
data on cause and effect relationships
and the effectiveness of control
measures, particularly best management
practices (BMPs) for nonpoint sources.
One situation where a phased
approach is used is where a TMDL
incorporates nonpoint source
allocations based on future
implementation of nonpoint source
control requirements. Such phased
TMDLs must include documentation
concerning the nonpoint source control
implementation plan and the basis for
projecting nonpoint source load
reductions. EPA will approve such
TMDLs only when there is a reasonable
likelihood that LAs will be achieved in
a reasonable time frame.
A phased TMDL could be used in
situations where a point source is
discharging to a water that does not
attain standards due in part to nonpoint
source loadings. One option for TMDL
development would be to identify BMPs
that are expected to reduce nonpoint
loadings such that the nonpoint source
contributions alone would result.in
attainment of water quality standards
with a margin of safety. If a State or a .
Tribe implements a program reasonably
anticipated to result in BMP
implementation, it could establish LAs
in a TMDL that reflect load reductions
expected through BMP implementation.
The WLA in the TMDL for the point
source could allow a discharge at a
concentration equal to (or in some cases
greater than) criteria or values.
EPA's approval of TMDLs (including
phased TMDLs) is case-specific, and
depends on a review of the technical
assumptions and procedures used to
develop the TMDL and, as noted above,
whether it is reasonable to expect that
anticipated nonpoint source controls
will be implemented and be effective.
c. Pollutant Degradation. One factor
that needs to be considered hi
establishing TMDLs is the possibility of
degradation of a pollutant after it is
released to surface waters. If there were
no degradation reactions taking place in
aquatic ecosystems (i.e., if all pollutants
behaved conservatively), every pollutant
released to the environment would be
present at some location. However,
there are natural physical, .chemical and
biological processes that serve to
degrade some pollutants and ameliorate
their impacts. These natural processes
include hydrolysis, oxidation, photo-
transformations (photolysis), and
biological transformation. Degradation
is different from pollutant transport,
which simply involves the movement of
a chemical in the environment and is
discussed below.
Existing EPA policy regarding the
environmental fate of pollutants is that
where data are available to support
estimation of degradation rates, it is
appropriate to include these
calculations when establishing TMDLs.
Two EPA references providing
information on environmental fate are •
Processes, Coefficients and Models of
Simulating Toxic Organics and Heavy
Metals in Surface Waters (EPA/600/3-
87/015; June 1987) and Water-Related
Environmental Fate of 129 Priority
Pollutants (EPA-400/4-79-029a,b;
December 1979),
d. Pollutant Transport. Pollutant
transport includes dispersion of
pollutants, in ambient waters, and the
movement of pollutants from the water
column to bottom sediments or to the
air. Transport within the water column
is relevant in establishing TMDLs where
States require criteria attainment at the
edge of allowed mixing zones. In such
circumstances it is necessary to
calculate pollutant concentrations that
will exist at the edge of the mixing zone
as 'a result of discharge-induced mixing,
currents and turbulence in the receiving
waters and pollutant dispersion.
Similarly, volatilization that occurs.
before the edge of a mixing zone can be
considered in determining the amount
of discharge that will not cause an
exceedance of water quality standards at
the edge of an applicable mixing zone.
Transfers to sediment may be taken into
consideration in establishing a TMDL,
but care must be taken to also account •
for pollutant release from sediments,
3. Development of the Proposed
Guidance
a. The Proposed Guidance. The Great
Lakes Technical Work Group attempted
to devise a single, consistent approach
for developing TMDLs to be used by all
States and Tribes in the Great Lakes
System. Current practice in the eight
Great Lakes States includes distinct
technical procedures and program
approaches which differ in scope, scale,
emphasis and level of detail. Although
there was broad general agreement on
dealing with TMDL development for
Open Waters of the Great Lakes
. (OWGLs), the technical work group
found it difficult to agree upon a single
set of procedures and processes to
establish TMDLs for tributaries. The
underlying reason for the inability to
reach a technical consensus is that there
are at least two views on how to-meet
the Clean Water Act's requirements for
establishing TMDLs for tributaries on a
large basin scale. One focuses first on
evaluating the basin as a whole,
followed by site-by-site adjustments.
The other focuses initially on evaluating
limits needed for individual point
sources with supplemental emphasis on
basin-wide considerations as necessary.
£oth approaches are consistent with the
Clean Water Act, but result in different
methodologies for TMDL development.
Each option provides that TMDLs be
established on a case-by-case basis by
the authorities responsible for
developing TMDLs.
The Steering Committee proposed to
include two options (Option A and
Option B) in the proposed Guidance and
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Federal Register / Vol. 58, No. 72 /Friday, April 16, 1993 / Proposed Aides,
20929
to solicit comments widely on all
aspects of both options. Option A is
presented as procedure 3A of appendix
A to part 132; Option B is presented as
procedure 3B. Option A utilizes the first
approach described above and is similar
to the approach currently used by New
York State. Option B utilizes the second
approach described above and is similar
to the approach used by several States
within EPA Region V. Option B
includes' specific formulae and
assumptions to be used in deriving
TMDLs. . :-'";'.
The proposed Guidance is not
intended to be a completely
comprehensive set of provisions
addressing all aspects of section 303 (d)
implementation by the States. ;
Accordingly, such matters as required
, submission by States and Tribes of lists
of waters needing TMDLs, are not
addressed in the proposed Guidance.
Current National regulations at 40 CFR
part 130, Would continue to apply in the
Great Lakes States.
Explicit guidance on deriving
nonpoint source load allocations and
implementing nonpoint source controls
are not included in the proposed
Guidance, While both options provide
general guidance on how TMDLs;should
consider nonpoint source loadings,
existing EPA regulations and technical
guidance should be used for these
purposes.
b. Overview of Option A and Option
B. Both options propose procedures for
.establishing TMDLs for open waters and
connecting channels and separate
procedures for establishing TMDLs for
tributaries to the Great Lakes, Both
options contain general conditions
applicable to all TMDL development,
and special conditions regarding control
of bioaccumulative chemicals of
concern (BCCs). Options A and B are
essentially the same with respect to
general conditions of TMDL
development, control of BGCs and the
development of open waters and
connecting channels. ,
The main differences between :the two
options exist in the development of
TMDLs for tributary discharges. These
differences are primarily in the
development of wasteload allocations
and focus on the degree of specificity
contained in the procedure and the use
"of mixing zones and margins of safety in
each, option. Option A and B are
discussed in greater detail below.
4. General Conditions of Application
Options A and B both contain the
same ten general conditions of
application. The general conditions
apply to every TMDL established under
the GLWQI and assure that TMDLs
employ consistent methodologies,
analytical approaches and assumptions.
a. General Condition 1, General
condition i establishes that, at a
minimum, TMDLs must be established
.for each pollutant for which itis
determined that there is a reasonable
potential' that a discharge will cause, or
contribute to an exceedance of WQS and
where the sum of existing point and
nonpoint .source (including natural
background) loadings exceeds the
loading capacity of the water under .:
investigation minus any margin of
safety. For additional guidance on when
TMDLs must be prepared, see 40 CFR
130.7.
b. General Condition 2, General
condition 2 establishes that aiTMDL for
a given pollutant must implement all
criteria for that pollutant that are
applicable to the water body in
question. As a practical matter, this will
normally involve identification of the
most stringent applicable criterion and
development of a TMDL based on its
implementation. General condition 2
also establishes that a TMDL must
consider point and nonpoint sources
and that the sum of the WLAs for point
sources, LAs for nonpoint sources, and
any specified MOS and reserve capacity
for future growth, shall not exceed the
loading capacity. This general condition
assures TMDLs will provide for
attainment of water'quality standards.
c. General Condition 3. General
condition 3 recognizes that TMDLs may
be developed for downstream waters
that will include WLAs for sources
already covered by a TMDL of different
geographic scope. For .example, a •
source-specific TMDL may already be in
place, when a basin TMDL is developed.
The condition requires that WQBELs in
NPDES permits be consistent with the
most stringent of the WLAs included in
any EPA-approved or EPA-established
TMDLs. This assures that water quality
standards will be met throughout a
drainage basin.
d. General Condition 4. General ,
condition 4 requires that each TMDL .
describe the manner in which a MOS is
provided and that MQSs be established
either by setting aside a portion Of the
loading capacity or by using
conservative modelling assumptions in
deriving"the TMDL. ..
e. General Condition 5. .General
condition 5 provides that States may
employ the provisions of section 510 of
the CWA to establish TMDLs more
stringent than those developed pursuant
to the proposed procedures. This
condition simply recognizes the
reserved right of the States to require
more stringent controls than those
required tinder the rWA. '' -
f. General Condition 6. General .
condition 6 establishes that TMDLs
must consider contributions to the water.
column from sediments inside and
outside mixing zones. Although TMDLs ,
are calculated on the.basis of pollutants
in the water column, all sources of •
pollution, including sediment re-release
to the water, column, must be
considered during the establishment of
the TMDL..
g. General Condition 7. General
condition 7 clarifies that the
implementation procedure for TMDLs
does not include explicit methods or
requirements for determining controls
necessary to ensure attainment of water
quality standards during wet weather
events. Nonpoint sources, storm water
discharges and combined sewer
overflows can typically be expected to
have the greatest impact On receiving
waters din-ing storm events. While
implementation procedures specific to
wet weather events are not included in
this Guidance, TMDLs must consider
pollution resulting from these wet
weather events. The procedures
contained in the proposed Guidance
may be appropriate in some case-
specific applications.
h. General Condition 8. General
condition 8 establishes the procedure
for determining representative
background concentrations of
pollutants. Procedures and assumptions
for calculating or identifying - v •
background assure that background
concentrations will be consistently
considered as TMDLs are established.
The first step in this process will be
selecting one of three possible data sets:
Representative caged fish tissue data,
representative ambient monitoring data,
or representative pollutant loading data.
While ambient monitoring data are
generally preferred over other data
sources, there may be instances where
the ambient data are not available, or
because of limits in analytical detection
methods, are not as informative or - '
reliable as either caged fish tissue or
pollutant loading data. Care must be
taken to ensure that the data represent,
or are adjusted to represent, ambient
conditions of .concern in the TMDL
development process. After a data set is
selected, a geometric mean is taken of
representative data points. -
With respect to pollutant loading
data, the geometric mean is taken of
pollutant loading data from individual
sources; the individual means are then
added to estimate total loading to the ;
receiving water. Background .
concentration is calculated by dividing
total loadings by the volume of water
available at the appropriate design flow
(which will vary depending on the
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Federal Register / Vol. 58, No. 72 I Friday, April 16, 1993 / Proposed Rules
criterion being implemented through
TMDL establishment) at the point
immediately upstream of the watershed,
water body or water body segment for
which the TMDL is being established.
Calculating the background
concentration of a pollutant using caged
fish tissue data or ambient monitoring
data generally does not require a
separate determination of the pollutant's
degradation or transport upstream of the
water body for which the TMDL is being
prepared. However, when actual
loadings are used to derive background
concentration, the assumption of
conservation of mass throughout the
sagmont of interest may not be accurate
for some pollutants. Pollutant
degradation or transport studies may
show that the substance does not
contribute to a problem after a certain
point downstream from the original
point of introduction into the water
body. The Steering Committee's
proposal on environmental fate
prohibited accounting for the
degradation or transport of a pollutant
that occurs outside of the mixing zone
for a point source, but that was coupled
with the Steering Committee's choice of
ambient monitoring data to determine
background, EPA believes that
accounting for degradation and
transport outside of the mixing zone
may be appropriate in circumstances
when background concentrations are
being calculated using actual loadings to
the system of interest. Accordingly, the
proposed Guidance provides for
consideration of pollutant degradation
and transport in such circumstances.
EPA invites comments on this issue.
Individual data points may not be
representative for a variety of reasons.
Best professional judgement will be
used to determine which data points are
acceptable. For example, a data point
may not be acceptable if reported as
below detection if the detection leve.l
itself is not reported. The permitting
authority should also consider detection
levels and quantification levels of data
whan determining what data are
acceptable. Recent data with improved
detection or quantification levels may
be acceptable, while some older data
with poorer detection or quantification
levali may render it unacceptable.
Care should be exercised in
determining what fish tissue data are
representative of background pollutant
concentrations. When using caged fish
tissue data to calculate background
concentrations, the geometric mean of
representative fish tissue analysis is
taken and that value will generally be
divided by the bioaccumulation factor
calculated for the pollutant in question
pursuant to the proposed methodology
in appendix B of part 132 to yield
estimated ambient concentrations.
However, where fish tissue data from a
single species are used to calculate
background calculations, and where
bioaccumulation data exist for that
species, it may be more appropriate to
use a species-BAF rather than a BAF
derived through the methodology in
appendix B. To be acceptable, the fish
must have lived within the geographic
area long enough to have reached or
approached steady state conditions in
terms of bioaccumulation. Steady state
occurs when the level of pollutant
uptake is approximately equal to the
level of pollutant elimination from the
fish. EPA guidance on these calculations
and considerations is provided in
Assessing Human Health Risks from
Chemically Contaminated Fish and
Shellfish: A Guidance Manual (USEPA,
September, 1989, EPA-503/8-89-002).
EPA intends to provide further guidance
through finalization of a draft document
entitled Assessment and Control of
Bioconcentratable Contaminants in
Surface Waters (March, 1991).
Within a given data set, some data
points may indicate that the pollutant
was not present at levels capable of
being detected by the analytical method
used. For these data points the true
concentration of the pollutant could be
anywhere between zero and the
detection level of the method. Other
data points may indicate that the
pollutant was detected, but at levels
below which the analytical method is
capable of reliable quantification. For
these pollutants, the true concentration
will be between the detection level and
the quantification levels of the
analytical method. Finally, there may be
data points showing reliably quantified
levels of the pollutant. Consistent with
the Steering Committee's intent, the
proposed Guidance would require, that
all data points showing that the--
pollutant is not present at the detection
level be considered to represent a
concentration of one-half of the reported
detection level, provided that at least
one data point is above the level of
detection. Similarly, for data points that
show that the pollutant is present at
concentrations between the detection
level and the quantification level, the
proposed methodology would provide
for use of a concentration equal to the
mid-point between the reported
detection level and the reported
quantification level. While this
condition was not addressed by the
Steering Committee proposal, EPA -
believes that.all these conditions are
necessary and appropriate for dealing
with values that are not detected or not
quantified.
EPA believes that it is necessary to
accord some weight to data points
below the detection level or
quantification level in calculating a
geometric mean; to do so requires the
selection of a concentration value
within the range of possible .values, EPA
is proposing to use one-half of the
reported detection level and also the
mid-point between the reported
detection level and reported
quantification level as reasonable
estimates of actual concentrations.
Where data are described as below the
detection level, EPA could also have
proposed to use either zero or the
reported detection level. Use of the
reported detection level in such
instances would result in the lowest
WLA for point sources, and while
certainly protective of water quality,
may require a greater reduction, in point
source loadings than necessary. Use of
zero in such instances would result in
the greatest WLA for point sources but
may not assure the attainment of water
quality standards. Because there is no ^
way to reliably quantify pollutant
concentrations below the detection
level, EPA believes that using one-half !
of the reported detection level is a
reasonable balance of the available
options. .
The proposed Guidance specifies,
however, that where all acceptable
available data points in a data set are
reported as below detection levels, then
all the data for that data set are assumed
to be zero. •
EPA also believes that a similar
reasoning supports the use of the mid-
point between the reported detection
levels and reported quantification level.'.
Under the proposal, States could always
choose a more stringent approach as a
general matter or in establishing
individual TMDLs.
The proposed Guidance includes a
definition of detection level that is ,
identical to the definition long used by
EPA, and published at 40 CFR 136.2(f).
There is no similar long-established
definition of the term quantification
level. The proposed definition is the
concentration at which a particular
substance can be quantitatively
measured. EPA solicits comment on •
whether this definition should be made
more precise and; if so, how it should
be changed. EPA is particularly
interested in whether a particular degree
of confidence should be specified.
A State's use of procedures for ,
estimating representative background
concentrations of pollutants shall be
reviewed by EPA on a case-by-case basis
when it approves or disapproves State
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Federal Register / Vol. 58, No. 72 / Friday, April 16,1993 / Proposed Rules _JQ931
TMDLs submitted under section 303(d).
The proposed requirements for .
determining representative background
concentrations are based on the current
practices of a majority of the Great Lakes
States. -. ;. . .•' v .,• •
,i. General Condition 9. General
condition 9 establishes that npnpoint
source load allocations must be based ,
on existing or anticipated increased
loading rates unless a lower loading rate
is reasonably.expected to occur within
a reasonable period of time as a result
of implementation of best management
practices or other control measures.
This general condition assures that,
• nohpoint source contributions will be
consistently considered as TMDLs are _
established and that anticipated .
reductions in loadings from nonpoint
sources will be used in establishing
TMDLs only where these reduced
loadings are reasonably expected to
occur. " . . .".
j. General Condition 10. General
- condition 10 requires that if WLAs are
.expressed as a concentration of a
pollutant in a discharge, that the TMDL
also specify the point source effluent
flow assumed in deriving the WLA. This
will facilitate establishment of mass
loading limitations in NPDES permits
: .pursuant toi lie proposed Guidance.
This general condition assures that
• common assumptions are used in
establishing TMDLs and corresponding
NPDES permit limits. '
• k. General Condition 11. General
condition 11 establishes that once a • ,
' TMDL is in place for a water body, a
riew source or new discharger can locate
on the. water body only if its loading is
" consistent with the existing TMDL (i.e.,
the TMDL included a reserved
allocation for future growth) or the
TMDL is revised to include an
allocation for the new source.,This
general condition assures that the
impacts of new sources will be
considered.
5. Special Provisions for BCCs
Bioaccumulative chemicals of
concern (BCCs) are those chemicals,
which'after considering metabolism and
other physicochemical properties which
might enhance or inhibit
bioaccumulation, have a BAF of greater
than 1000. Although levels of certain
BCCs have significantly declined in
recent years, -the rate of decline has
diminished and contaminant levels •
appear to be levelling off. It is estimated
that .under current loadings it will take
years, perhaps decades, for fish tissue
concentrations of certain BCCs to
decline to levels that would allow
unrestricted consumption of fish in the
Great Lakes. Due to the unique
characteristics of the Great Lakes,
.primarily long pollutant residence
times, the Steering Committee wished to
assure that similar problems did not
occur in the future for other BCCs. A
more detailed description of the
.rationale for,the proposed increased ,
controls on BCCs is provided in section
I.D of this preamble.
a. Reason for Restricting Discharge, of
BCCs. The proposed Guidance would
restrict the introduction and
accumulation of BCCs in the Great
Lakes System by requiring, in general,
that mixing zones for existing .-"•'.
discharges of BCCs be eliminated within
10 years and for new sources, that no
mixing .zone be provided. This proposed
restriction reflects the Steering v .
Committee's belief that every reasonable
effort should be made to reduce all .
loadings of BCCs. In particular, the
Steering Committee believed mixing
zones should be eliminated for BCCs as
a way to reduce mass loadings to the
Great Lakes, The Steering Committee's
approach is discussed further in section
I.D of this preamble. EPA is seeking
comment on whether the elimination of
mixing zones over a 10-year period is an
appropriate mechanism for addressing
concerns with BCCs in the Great Lakes
System. , •'
. b. Elimination of Mixing Zones for
BCCs. Mixing zones are areas within the
water body where the effluent mixes
with the receiving water and where
chronic water quality standards, are not
required to be met. Mixing zones for
existing discharges of BCCs are
proposed to be eliminated after a ten
year period, after which time
concentrations in any discharge which
has the reasonable potential to.cause or
contribute to an excursion above a BCC
criterion of value must be at or below
the water quality criterion or value for
the bipaccumulative pollutant. This ten
year time period equates to two five- -
year terms for NPDES permits. This time
period represents a reasonable period
for implementing the phase out that
works toward the Great Lakes Water
Quality Agreement goal of virtual
elimination of persistent toxic
substances. .
The concept of eliminating mixing
zones for BCCs is consistent with
current National regulations and
guidance and the Great, Lakes Water .
Quality Agreement. EPA regulations
provide that States may, at their
discretion, provide for mixing zones as
part of their State water quality
standards. The TSD recommends that
States prov^e a definitive statement in
.their water quality standards as to
whether or not mixing zones are . .
allowed and states. As our _^., „
understanding of pollutant impacts on
ecological systems evolves, there insy be
dases identified where no mixing zone .
is appropriate. In addition, a general -
principle of the GLWQA at Annex 2
Paragraph 2.(d) supports the elimination
of point source impact zones (mixing
zones) for toxic substances.
c. New Sources. New sources of BCCs
are riot afforded the phase-in time. New
sources that have a reasonable potential
to cause or contribute to an excursion
above a BCC criterion or value are to
achieve the criterion/value at the
discharge point at the time of -
commencing discharge. •
d. Mixing Zones During the Ten Year
Phase Out. Until mixing zones for
existing sources of BCCs are phased out,
TMDLs that include WLAs for such -,--,
sources would be established using the
mixing zone provisions set forth in each
option or, where there are no specific
provisions, in accordance with x
applicable requirements of State law.
e. Exception to the Ten Year Phase
Out of Mixing Zones. Both options *
provide an exception to the required
elimination of mixing zones (sections
B.4 of both procedures 3A and 3B).
Limited mixing zones may be granted
beyond ths ,10-year period where water
conservation measures leading to
overall load reductions are used. When
a facility implements water
conservation measures, the
concentration of the pollutant in the
effluent may increase while the mass of
the pollutants discharged does not. The
Steering Committee believed that the
effect of eliminating mixing zones could
discourage permittees from utilizing •
water conservation measures, because of
the potential for pollutants to increase -
in concentration in the effluent, causing
a higher possibility that compliance
with the concentration-based effluent
limitation would not be achieved. The
Steering Committee believed that "
because water conservation is desirable,
that an exception may be appropriate in
certain circumstances. The primary
concern for BCCs is the mass of the
pollutant entering the Great Lakes •
System. Concentration levels would still
be controlled to assure no short term
affects in the mixing zone. In no event,
however, may the State grant mixing
zones larger than those available when
non-BGCs are discharged pollutants.
6. TMDLs for Open Waters of the Great ,
•Lakes -"- ..- .-'- ..-, •'.. • v,-.'" -,.'. ;.. ...',,-:
Both options describe the process fpr ,
developing TMDLs for OWGLs; inland;
lakes and other waters of the Great >
Lakes System that exhibit lentic , —
conditions (section 3.G of both -, •? _•.
procedures 3A and 3B). In both options,
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
general guidance for development of
TMDLs on a lake-wide basis is
provided,
a. Point Source Mixing Zones for
Chronic Criteria and Values. Both
options provide that absent a mixing
zone study, individual wasteload
allocations for point sources not be
based on • mixing zone larger than is
provided by mixing one part effluent
mixed with ten parts lake water
(containing background concentrations
of pollutants). A smaller mixing zone or
rato discharge may be deemed
niceisary to meet criteria and values,
The 10:1 mixing factor was derived
from mixing zone studies conducted for
tho Milwaukee Metropolitan South
Shora wastewater treatment plant and
for the Green Bay Metropolitan
wastowater treatment plant. For these
cases, it was shown that the ten to one
mixing factor represents an area of
mixing where the velocity and
momentum associated with an effluent
being discharged from the end of a pipe
is dissipated and any further dilution or
mixing which then occurs is associated
only with the typically slower natural
process of diffusion, wind, temperature
or current induced dispersion. The
mixing zone assumption for open lake
discharges accounts for background
concentrations in the lake and
essentially bases the TMDL on meeting
criteria and values when one part
effluent is mixed with ten parts lake
water. Option A describes the 10:1
mixing zone in a narrative format, while
Option B embodies the concept in a
formula.
Under Option B, for non-BCCs, when
a party believes that the 10:1
assumption does not reflect tha actual
a»a of discharge-induced mixing, a
different mixing zone may bs provided
if the provisions of section 3.E of
procoduro 3B are met. Under Option A,
the mixing zone available is not
necessarily constrained by the area of
discharge induced mixing if it is
demonstrated that an alternative mixing
zone is appropriate for protection of
designated and existing uses and
implementation of all criteria and
values.
EPA invites comment on the relative
merits of those different formats.
b. Calculating Load Allocations.
Under both options, appropriate
dilution assumptions to be used when
establishing load allocations for
nonpoint sources shall be determined in
accordance with State law on a case-by-
casa basis by the authority establishing
tha TMDL.
c. Protection from Acute Effects,
Option A provides for a cross check to l
ensure that acute criteria are met within
applicable acute mixing zones
authorized under State law. The option
does not include a specific final acute
value (FAV) cap, but instead relies on
site-specific analysis of limits necessary
to assure attainment of acute criteria
and values within the applicable acute
mixing zone.
To protect against acute effects in
mixing zones, Option B requires that.
effluent limitations for point sources
never exceed the final acute value
(FAV). In some circumstances, however,
the effluent limit may be required on a
case-by-case basis to be more stringent
than the FAV to protect against acute
effects. The FAV is twice the CMC, as
provided in the methodology for
derivation of aquatic life criteria and
values (appendix A to part 132).
d. Procedures When High Background
Concentrations are Present. Under both
Options, specific procedures are only
provided for the situation where
background concentrations do not
exceed criteria or values. When ambient
water quality concentrations do exceed
chronic narrative or numeric criteria or
Tier II values, any discharge that has a
reasonable potential to cause or
contribute to an excursion above a
criterion or value should either be
prohibited or a multiple source TMDL
established that ensures the attainment
of criteria or values. Under both
Options, the procedures used in
developing multiple source TMDLs for
discharges to OWGL and other lentic
waters are to be developed on a case-by-
case basis, consistent with applicable
regulatory requirements. There may be
situations in which a phased TMDL is
most appropriate. In a phased TMDL,
best professional judgement is used to
derive LAs and WLAs that will lead to
attainment of water quality standards
with a MOS. However, for example, due
to large nonpoint source contributions
and uncertainties regarding current
loadings and probable success of
nonpoint source controls, it is necessary
to carefully monitor the effectiveness of
the controls developed as a result of the
TMDL. The phased TMDL and controls
must result in attainment of water
quality standards within a reasonable
period of time, although during the
implementation of controls, there will
be a period of time when water quality
standards may not be met. Frequent
monitoring of the effectiveness of
controls, particularly nonpoint source
controls, is necessary in order to
determine both the validity of the
phased TMDL and the ultimate success
of controls in attaining wate^quality
standards.
Under the proposed procedure 9 of
appendix F to part 132, compliance
schedules in NPDES permits for point
sources are limited to-three years. Thus,
there is a maximum period of eight
years after the establishment of a TMDL
in which permits can be reissued and
point source limits consistent with a
TMDL can be attained (five years for the
expiration of existing permits and three
years for the permittee to come into
compliance with a new limit based on
a TMDL). EPA also believes that in most
situations it is appropriate to factor
nonpoint sources reductions that are
reasonably expected to occur within an
8 year time period into a TMDL, absent
case-specific considerations.
. e. Margin of Safety—L Chronic
Criteria and Values. In situations where
background concentration do not exceed
criteria and values, EPA believes that a
MOS is generally provided through the
use of a ten to one mixing zone. Given
the size of the OWGL and other lentic
receiving waters in the Great Lakes -
System, such a limited mixing zone
provides a MOS with respect to
attainment of water quality standards in
ambient waters. In situations where a
larger mixing zone is allowed based on
a mixing zone study, the TMDL must
include an explanation of how the MOS
is provided.
li. Acute Criteria and Values. EPA
believes that restricting effluent levels to
less than or equal to the FAV for acute
criteria and values, provides the needed
MOS. In other situations, such as
TMDLs developed under Option A
allowing larger loadings, the TMDL
must include an explanation of how the
MOS is provided.
7. TMDLs for Discharges to Tributaries
The principal differences between
options A and B relate to TMDL
development for tributaries. The initial
focus of Option A is on attainment of
water quality standards in a tributary
basin, followed by assuring that water
quality standards are attained at
discharge points throughout the basin'
Option A does not specify the size of
mixing zones, leaving such
considerations to existing State
requirements. Option B, on the other ,
hand, has detailed procedures for
developing tributary basin and source
specific TMDLs that are applicable
where background concentrations do
not exceed water quality standards.
These detailed procedures include
specific mixing zone provisions. Option
B envisions development of tributary
basin TMDLs at the discretion of the
TMDL authority, or where the source
specific procedures are not applicable or
appropriate.
a. Steady State Mass Balance
Approach Common to Both Options.
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20933
Both options envision predominant use •
of a simple, stead;yVstate mass balance
approach. A mass balance approach is a
method used to approximate the mass of
pollutants within a water body. It is
based on the physical law of ,
conservation of mass thatstates that ;
mass cannot be created or destroyed but
only transformed. This approach
assumes that the input or mass into the
system (e.g., through point and ;
nonpoint source loadings, atmospheric
deposition, groundwater seepage) equals
the loss of mass from the system plus
any losses due to transformation of mass
within the system. Because both options
assume a simple steady state, it-is _
assumed that no mass can be
accumulated in the system. This
provides for a first approximation of
allowable loading allocations.
Subsequent monitoring will identify any
shortcomings to this approach and
indicatejwhether revisions are •
necessary. Although Options A and.B
are based on steady state conditions
which assume fixed low flows, EPA is
seeking comment on whether the final
rule should allow the use of more
sophisticated dynamic flow models.
b. Design Flows Common to Both
'Options. Many of the point source.
dischargers regulated under the Clean
Water Act discharge effluent ,
continuously toflowing streams.
However, the amount of water available
to dilute the discharge typically varies
: with the season and with, periodic storm
or drought conditions. In deriving
TMDLs it is necessary to determine the
stream conditions under which criteria
and values must be attained. The .
criteria and values derived pursuant to
today's Guidance are not designed to be
never-exceeded values. Rather, they
may be exceeded at varying frequencies
and durations without injury to human
health, wildlife or aquatic life.'
' Both options specify tributary design
- flows at which criteria and values are to
be attained. The volume of water
flowing through the tributary in a given
time period at the design flow
conditions is the volume that is
considered available to dilute all
pollutants present or introduced into
the water body. Because of differences .
in criteria derivation methodologies, the
proposed Guidance specifies different
design flows for chronic aquatic life,
wildlife, and human health criteria. For
WLAs based upon chronic aquatic life
criteria or values^ the hydrologically-
based 7Q10 flow or the biologically-
based 4B3 flow is used; for TMDLs
based upon wildlife criteria or values,
, the hydrologically-based 30Q5 flow is
used; and for TMDLs based upon
human health criteria, the harmonic
mean flow is used. . - . '
With respect to implementing chronic
aquatic life criteria using a mass balance;
approach, the proposed Guidance
specifies the use of either the 7Q10
design flow or the 4B3 biologically-
based design flow.
The 4B3 is that flow determined on a
case-by-case basis that would provide
for an excursion of chronic aquatic life
criteria, over a 4-day averaging period,
only once every three years. This flow;
is selected because criteria developed'
pursuant to procedures in the proposed
Guidance may be exceeded over a 4-day .
averaging period once every three years
without injury to the aquatic ecosystem. •
(See Technical Support Document to
Water Quality-based Toxics Controls, or
TSD)
; The biologically-based 4B3 flow can
be calculated by the computer program
DFLOW supported on EPA's computers
at the National Computer Center in ,
Research Triangle Park, NC. (Further
information may .be obtained from
Assessment and Watershed Protection
Division, U.S. Environniental Protection
Agency, 401 M St, S.W., Washington, -.
D.C. 20460)
The second alternative design flow .
allowed in the proposed rule is the
hydrologically-based 7Q10 flow. The
7Q10 is the lowest 7-day, average flow
expected to occur on the average once:
in every ten years, based on the period
of record. Empirical data from
approximately 60 streams show that the
7Q10 flow provides a degree of
protection approximately equivalent to
the 4B3 flow. Statistics based on stream
. gages operated by the U.S. Geological
Survey are routinely published. These
statistics commonly include estimates of
the 7Q10 for most riverine systems.
EPA solicits comment on whether the..
final rule should specify a design flow
for the purposes of implementing acute
aquatic life criteria. Current EPA
guidance recommends use of a IQIO for
this purpose (Technical Support
•Document for Water Quality-based
Toxics Control). The design flow would
be used in conducting acute cross-
checks under Option A, andln .
determining whether the FAV cap is
sufficient to protect against acute effects
in Option B. -,':'-.' -- <
Human health criteria represent
ambient pollutant concentrations that
are acceptable based on a lifetime (70
years) of exposure. Accordingly,
discharges shouldbe regulated such that
criteria will not be exceeded under
stream conditions that represent long-
term average conditions. Current EPA
guidance recommends, use of the long-
term harmonic mean flow to implement
human health criteria (TSD). The
harmonic mean flow is the sum of the
reciprocals of individual flow
measurements divided into the total
number of individual flow
measurements. .
Since wildlife criteria have not been
implemented by EPA before, there is no
current EPA guidance regarding a
design flow for their implementation.
Based on the recommendations of the
State of Wisconsin and the GLWQI
Steering Committee, EPA is proposing
that a 30Q5 flow rate be used for the
implementation of wildlife criteria. This
is the lowest 30-day average flow that
would occur on the average every five
years based on a statistical review of .-..-.
historic flow data.
-The Steermg Committee's starting ;
point in selecting a 30Q5 flow rate for • •
wildlife criteria was analysis of the :
7Q10 flow rate currently used in the •
implementation of aquatic life criteria.
For wildlife, impacts of chemicals with,
a high propensity to bioaccumulate in
aquatic organisms is of greatest concern.
Aquatic organisms comprise a major
portion of the diet of many wildlife .
species. Because of relatively slow ra.es
of uptake by aquatic organisms of
bioaccumulative chemicals, residues in
the food chain would have a delayed .
response to increases in ambient
concentrations of chemicals during
short-term periods, such as during low/
flow events. Accordingly, the Steering! ,
Committee judged a 30-day averaging
period was more appropriate than the 7-
day averaging period used in the aquatic
life design flow. The Steering
Committee selected a five-year return
interval as adequate to ensure that
criteria exceedances did not occur too
frequently to interfere with
reproduction of wildlife species, and no
unacceptable adverse effects on the
population would result
EPA recognizes that the .use of a 30-
day averaging p'eriod is conservative
given the: long time it may take for
bioaccumulative chemicals to reach
steady state in an aquatic organism. EPA
is interested,in receiving comments on
the proposed 30Q5 design flow for the
implementation of wildlife criteria.
Given the long time to equilibrium for r
bioaccumulative chemicals, EPA
particularly solicits comments on
whether, a 90Q10 flow, the long-term
(period of record) harmonic mean flow,
or the lowest annual harmonic mean
flow expected to oecur on the average
within a 5 or 10 year period shouldbe. .:
used for the implementation of wildlife
criteria. The latter two alternatives ;'
above are iessentially a 365Q5 or
365Q10, where a harmonic mean rather
than an arithmetic mean is used.
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20934
Federal Register 7 Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
Comments are requested on these flow
rates because the harmonic mean is
recognized as a better predictor of the
average concentration than is the
arithmetic moan.
Tha requirements in the proposed
Guidance for use of design flow are
consistent with the recommendations in
tJie TSD. A more complete description
of tho selection of design flows, steady-
state and dynamic modeling
approaches, and the reasons for the
requirements in today's proposed rule
may be found on pages 36. 78-82, and
appendix D of that document EPA
invites comment on the use of these
design flows and on the use of steady-
state and dynamic modeling
approaches.
c. Overview of Option A—L Load
Inventory. A load inventory is prepared
under Option A that documents all
loadings from point and nonpoint
sources to the entire basin. Option. A
allows a number of different data
sources to be used in calculating
loadings from point sources: Current
NPDBS permit limits, calculated limits
reflecting now technology-based
requirements, interim limits in an
enforceable schedule of compliance,
and actual loadings of pollutants
determined, for example, through
discharge monitoring. Tha data source
actually used in a load inventory should
ba determined on a case-by-case basis,
with tha objective of ensuring the
ultimata success of the TMDL in
bringing about attainment of water
quality standards.
The load inventory also includes
natural background loadings of
pollutants, and loadings from nonpoint
sources It may be particularly difficult
to assess loadings from nonpoint
sources. Any uncertainties in this regard
should be reflected in the margin of
safety established for the TMDL.
Pollutants may degrade into non-toxic
byproducts as they travel from the point
of discharge to the farthest downstream
location in the tributary basin. It is
permissible to discount pollutant
loadings to the farthest downstream
point of the basin to the extent that
degradation can be estimated with
accuracy.
it. Loading Capacity. The next step in
deriving a tributary TMDL under Option
A is to calculate the total loading of
pollutants that can enter the basin and
still ensure attainment of all applicable
water quality standards at the furthest
downstream location in the basin. When
chronic numeric criteria or values are
available, this loading capacity is
calculated by multiplying the numeric
criterion or value, expressed as a
concentration of pollutant, times a given
tributary design flow. As is discussed
above, the design "flow varies with the
type of criterion or value being
implemented. For example, the loading
capacity associated with attaining
chronic aquatic life criteria is calculated
for a design flow representing the lowest
7-day average flow that occurs once
every 10 years, Tha loading capacity
associated with implementing human
health criteria or values, on the other
hand, is calculated based on the
harmonic mean flow of the stream.
Thus, for example, if a human health
criterion is expressed as 10 milligrams
of pollutant per liter of water, and 10
million liters of water pass the lowest
downstream location of the tributary
during a day at the harmonic mean flow,
then the loading capacity of the
tributary would be 100 kilograms of
pollutant per day;
Where numeric criteria or values have
not been calculated, a case-by-case
determination must be made as to the
loadings of pollutants to the tributary
that are consistent with attainment of
narrative water quality criteria and
protection of designated and existing
uses.
If degradation is assumed in
calculating the baseline inventory, it
should also be assumed in calculating
the loading capacity of the tributary
basin. This may be difficult, however,
since the loading capacity will vary
depending on where the pollutants are
introduced. Correlation to existing
loading patterns will ensure the most
accurate estimate of loading capacity
given the current discharge situation.
iii. Basin Margin of Safety. TMDLs are
to be derived with a margin of safety to
account for uncertainties. An
assessment of uncertainties hi
calculating the loading inventory and
loading capacity should be made, and a
portion of the basin loading capacity set
aside as a margin of safety that reflects
the uncertainties presented. Of course, if
the loading inventory and loading
capacity are initially calculated in a
conservative (protective of the
environment) manner, then a separate
set-aside of loading capacity for a
margin of safety may not be necessary,
iv. Load Reduction Targets. The
loading capacity minus any specified
•basin margin of safety is the loading that
is available for allocating to all sources
(including natural background) of the
basin. The amount of load reduction
necessary to meet water quality
standards at the downstream end of the
tributary can be calculated as the
baseline inventory load minus the basin
loading capacity adjusted by any
specified basin margin of safety.
v. Basin Allocations. Allocations are
made consistent with load reduction
targets identified above. TMDLs must
not include allocations which are not
reasonably anticipated to be attained. :
Accordingly, load allocations for
nonpoint sources should be based on
current or anticipated increased
loadings, unless there is a reasonable
bdsis for assuming that there will be a
reduction in nonpoint source loadings
within a reasonable time period. As
discussed above, EPA will typically
consider eight years to be a reasonable
time period. Whatever portion of the
loading capacity is not allocated to
nonpoint sources, background, and
reserve capacity for future growth may
be allocated to existing point source "
dischargers,
vi. Site-specific Cross-checks. After
allocations are established to ensure
attainment of water quality standards at
the furthest downstream location in the
tributary, site-speciEc cross-checks are
conducted at each source location to
ensure that water quality standards
(acute and chronic aquatic life, wildlife
and human health) are attained at the
edges of applicable mixing zones .or. if
mixing zones are not allowed under
state law, throughout the basin. Option
A does not specify the size of mixing
zones for this purpose; mixing zone
requirements (if any) adopted by the
various states will be used for the cross-
checks. The cross-checks should apply
the margin of safety concept to the local
discharge area. In addition, they must
account for background concentrations
of pollutants in tie immediate vicinity
of the discharge.
If a site-specific cross-check indicates
that standards will not be attained in the
vicinity of a nonpoint source, the LA
may be reduced if such a revised LA can
reasonably be expected to be promptly
attained by that source in a reasonable
time period. Otherwise, WLAs for
upstream point sources must be reduced
to ensure attainment of standards in the
vicinity of the nonpoint sources. In
some instances it may be more
economical for the upstream point
sources to fund nonpoint source control
measures to achieve needed load
reductions than to institute additional
treatment measures at their locations. If
such ah agreement is binding on the
parties and can reasonably be expected
to promptly provide the needed load
reductions in a reasonable time period,
the TMDL can include a reduced load
allocation reflecting the agreement.
vii. Establish Final Allocations. Final
allocations in TMDLs developed under
Option A are the more stringent of those
developed through the basin analysis or
through site-specific cross checks..
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Federal Register / Vol. 58, No. 72 /* Friday rApril ifr. 1993V/Proposed Rules' 26935*
However, if certain basin allocations are
reduced as a result of site-specific cross
checks, other basin allocations could be
correspondingly increased provided that
such increased allocations are deemed
acceptable after conducting site-specific
cross-checks.
; viii. Monitoring Provisions, If there is
a significant nonpoint source
contribution of the pollutant addressed
in the TMDL, the TMDL should
typically include, a monitoring plan that
will test the success of the TMDL in
leading to attainment of water quality
• standards. States may consider
performing the monitoring themselves,
or requiring ambient monitoring as a
condition of NPDES permits issued to
point source dischargers of the
pollutant. If the ambient monitoring
indicates continued exceedances of
water quality standards, the TMDL
should be revised to include more
stringent allocations. Such phased
TMDLs are appropriate when nonpoint
Sources are present because it is
currently very difficult to accurately
estimate nonpoint source loadings and
reductions that can be achieved through
implementation of nonpoint source
controls.
d. Overview of Option B, Option B
includes detailed procedures to derive
tributary basin and source specific
WLAs for point sources where ;
background concentrations do not
exceed water quality standards, but
where the additional discharge of the
point source or sources in question has
a reasonable potential to cause or
contribute to such an exceedance. ,
The detailed source specific .
procedures could pose an inequitable ,
burden in some situations on the
particular point source responsible for
' the marginal loading that could result in
a water quality standards exceedanee.
Upstream sources also contributing to
the water quality impairment would not
need source-specific TMDLs under this
approach. Accordingly, Option B also
includes an approach for deriving
tributary basin TMDLs that would
spread the load reduction burden among
a number of sources. A tributary basin
TMDL is also necessary where
background loadings at point source
locations exceed applicable water
quality standards.
Consistent with the general
conditions set forth in section A.2 of
procedure 3B, the tributary basin TMDL
will include WLAs for point sources
and LAs for nonpoint sources such that
their sum is not greater than the loading
capacity minus the stun of any specified
MOS and reserve capacity for future
growth. Also, each individual WLA
must be no less stringent than the
requirements for source specific TMDLs
as specified in section D.3 of procedure
3B, . "' --•'•;'.' ••'- •'.-.- •
i. Source-specific TMDLs. Option B ,
includes a formula in section D.S.c.i of
, procedure 3B for deriving a WLA in
situations where background
concentrations do not exceed water
quality standards. By considering •"" .
background concentrations in the
formula, all upsbeam loadings are
accounted for, and a WLA" is generated
that will ensure attainment of water
quality "standards at the discharge ;
location. The proposed formula reflects
current EPA guidance for deriving a
WLA using steady state mass-balance
assumptions: -'.-.-
™ A ^
WLA <:
(criterion)[Qad + (1 - f )(efiPuent flow)] - (background)Qad
-,., • . -
effluent flow
. The formula contains five major
functional components. The first
component of the formula is the WLA—
the mass of pollutant that may be
discharged over a given period of time
by the point source and still provide for
attainment of water quality standards.
The second :major component of the
formula is:
: , (criterion)^ + (1 - f )(effluent flowJ]
.This set of terms calculates the mixing
zone capacity (expressed as mass of
pollutants per unit of time) within a ' .
specified mixing zone and accoimting-
for water introduced by the point source
to the stream. The third major •
component of the formula is
(background)Qad. This component
calculates the loading (also expressed as
mass of pollutants per unit of time) ••
already present in the volume of stream
flowing to the discharge location that
will be used for mixing. -The mixing
zone capacity minus the background
loading yields the additional point
source loading (in mass per unit of time)
that may be discharged without causing
an exceedance of water quality,
standards. When this is divided by the
effluent flow in units of volume per unit
time, the fourth major component of the
formula, it yields a concentration that
may be discharged (in units of mass per
volume of flow). The fifth factor in the
equation, X, is used to convert-the
concentration based value to a mass
based discharge limitation expressec
over an appropriate time period (such, as
mass discharge per day). The loading
capacity and background loading
components of the formula are
described in more detail belowi
ii. Mixing Zone Capacity. The mixing
zone capacity is the capacity to
assimilate pollutants and attain criteria
in the portion of the stream designated
for mixing, assuming no pollutants
present,'and is provided by:
aj.+(1<- f )(effluent flow)]
The criterion is a chronic Tie): I
criterion, chronic Tier n value, or oilier
numeric criterion or numeric
interpretation of a narrative criterion,
expressed as a concentration of the
pollutant. A chronic criterion or value .s
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20936 Federal Register . Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
designed to protect against effects that
may arise due to long-term exposure.
Such criteria are typically more
stringent than acute criteria, so this
implementation typically also provides
protection from acuta or subchronic
effects, depending upon mixing zone
considerations.
Tha Qfd is that portion of the
receiving water at an appropriate design
flow that is allowed to oe used to dilute
the discharge. Section D,3.c.ii of
procedure 3B specifies that the Q»d is
calculated by multiplying the stream
design flow by the dilution fraction. As
discussed in more detail above, the
design flow of the stream varies with the
type of criteria being implemented (e.g.,
chronic aquatic life or human health),
and accounts for the fact that there
typically will be differing amounts of
dilution water available in a stream
depending on the season and periods of
drought or flooding. WLAs for
continuous discharges must consider
this variability in receiving water flow.
The dilution fraction is derived based
on the relationship of the effluent flow
of the point source to the flow of the
receiving water, and an assumption
regarding how rapidly mixing occurs.
Stream data showing effluent and
receiving water flow show that the
discharge from a point source to a small
stream will mix relatively rapidly with
a greater percentage of the water in the
receiving stream as compared to the
discharge of a similar point source to a
large stream. The ratio of the stream
flow to the effluent flow is used in
section D.3.c,iii of procedure 3B to
determine the amount of flow to be
granted as the default dilution fraction.
Tha dilution fraction varies from 0.1 to
0.25, depending on this ratio. Thus, the
dilution fraction specifies the size of the
mixing zone in terms of the percentage
of stream flow (10-25 percent) that is
available for dilution. The proposed
Guidance provides for an opportunity to
demonstrate that a larger mixing zone is
acceptable within the constraints set
forth in section E. In no case, however,
may the dilution fraction exceed 0.75.
The concept of the fraction of the
stream design flow is based upon
recommendations found in the Water
Quality Criteria—Report of the National
Technical Advisory Committee to the
Secretary of the Interior, April, 1968
(Green Book) and upon guidance from
EPA's 1983 Water Quality Standards
Handbook. The Green Book
recommended that in order to prevent
the initial mixing of wastewater of point
sources from erecting a barrier to fish
and other aquatic organisms, only 25
percent of the cross-sectional area of the
river should be used for mixing. The
Handbook suggests that the value of 25
percent of total river flow is a rational
estimate of the amount of river flow in
25 percent of the cross-sectional area.
The basis of the use of a fraction of the
cross-sectional area is then tied to the
allowance forjmixing zones found in
each State's water quality standards.
The use of the 25 percent fraction has
been incorporated as policy in the water
quality standards of some States across
the Nation and included in the Great
Lakes System for many years in order to
account for the uncertainties
surrounding available data, discharge
fluctuations, impacts on aquatic
resources, etc. Option B's use of a
fraction of the cross-sectional area for
.deriving WLAs is consistent with the
longstanding EPA guidance and State
policies on mixing.
The proposed procedure specifically
sets the default dilution fraction to vary
inversely with the stream flow to
effluent flow ratio. A larger portion of
the stream design flow is allowed for
those situations where the source flow
closely approximates the stream design
flow. This means that when the effluent
mixes with the stream rapidly, a larger
portion (25 percent) of the stream is
justified as a dilution fraction. But when
the effluent does not mix rapidly with
the stream, a smaller portion (10
percent) of the stream flow is justified
as a dilution fraction. This reduction in
the dilution fraction effectively reduces
the volume of water available for
dilution in larger rivers. This reflects a
compromise approach when compared
to some States within the Great Lakes
System. For example, the State of Ohio
uses a graduated scale for the fraction
that ranges between 10 percent and 100
percent of the stream design flow. The
State of Michigan, on the other hand,
uses a straight 25 percent of the stream
design flow for all categories of criteria
or values, with an opportunity to
demonstrate for a larger percentage.
Similar to the approach used by Ohio,
the dilution fraction is only determined
based upon the ratio of the 7Q10 to the
effluent source flow. Once a dilution ,
fraction is determined, the same
dilution fraction would be used when
assessing the need for all water quality-
based controls for a particular
discharger. As required by the proposed
Guidance, the dilution fraction would
never be determined using the harmonic
mean 30Q5 flow of a receiving water.
The constant dilution fraction for
varying stream design flows is specified,
in order to ease administrative burden. •
EPA solicits comments on the proposed
method of calculating a default dilution
fraction, and also solicits suggestions
(with supporting rationale) for
alternative methods.
EPA believes that the dilution fraction
provisions are conservative, and
contribute to a margin of safety for
TMDLs derived using the equations. As
such, EPA believes that in most
situations an additional margin of safety
will not need to be provided when this
equation is used to derive source-
specific TMDLs. This procedure,
however, may not provide an adequate •
MOS where there is more than one
discharger in a relatively short stretch of
river where the design flow (drought,
flow) of the receiving stream does not
substantially increase between the
upstream and downstream dischargers
or where background levels are high. In
such a situation, the tributary basin
procedure should be used, or some
other method used to provide an
adequate margin of safety.
The approach is somewhat more
conservative (contributes more to a
MOS) with respect to TMDLs for
wildlife and human health criteria,
since the dilution fraction is always
calculated using the low design flow
(7Q10) used to implement chronic
aquatic life criteria. EPA believes that
use of the formula will promote
consistency in developing TMDLs in the :
Great Lakes System. Comments on the
proposed mixing zone/margin of safety
approach built into the formula are,
specifically invited.
The component of the formula that is
used to calculate loading capacity also
includes the terms (1-fj(effluent flow).
"f is defined as the fraction of the
effluent flow that is withdrawn from the
receiving water.
The (1-f) factor is applied to take into
account whether or not the point source
is increasing stream flow (and available
dilution) by adding water to the
receiving stream. In situations when the
receiving water of the discharge is the
same water body as the facility's source
water, the flow from the effluent should
already be accounted for in the stream
flow value and the receiving water is
only receiving additional loading of
pollutants. Where the'facility source
water is from a different water body
than the receiving water, the factor has
the effect of increasing the allowable
dilution flow of the stream to account
for the additional water introduced by
the point source.
iii. Background Loadings. The
background conditions of the receiving
water are accounted for in the formula -
in proposed section D.3.c.i of procedure
3B by the term (background) Qad. As
discussed above, Q^ is the portion of
the receiving water that is allowed to
dilute the discharge. When this flow is ;
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Federal Register / Vol, Sft, No, 72, / Friday, April 16, 1993 /Proposed;' Rules
20937
multiplied by the background
concentration of pollutants in the
receiving water immediately upstream
:of the point source (calculated in
accordance with section A.S), the result
is a background loading of pollutants in
the portion of the receiving water flow
.that is available for diluting the
discharge, in units of mass of pollutants
per unit of time. . ., .. ' •
' iv. Formula Modification Based an.
Mixing Zone Studies. Option. B allows
any interested party to prepare a mixing
zone; study and allows the TMDL
authority to modify the dilution fraction
described, above in accordance 'with
such studies. The dilution fraction -
could be either reduced or eliminated,
or increased to a maximurja. of 75
percent of the 7Q10 flow. Option B;
section E describes several required
elements of a mixing zone study, all
designed to address the area of mixing
that can be allowed consistent with
attainment of water quality standards.
Mixing zone studies are to assume that
pollutants do not degrade within mixing
zones, unless the mixing zone study is
accompanied by scientifically valid
field studies or other relevant
information demonstrating that ,
degradation of the pollutant will occur
in the mixing zone under the full range
of environmental conditions expected to
be encountered and such studies or
other, information also address factors
other than degradation, that affect the
level of pollutants in the water column,
tncludina resuspension of sediments,
chemical speciation, and .biological arid
chemical transformation. .
v. Limitation on Use of Source-
specific TMDL Formula. In situations
where the term, (background) Qad is
larger tharLthe term Ccriterion)[Qad +. (1-
. f)(effluent flow}}, the formula will
generate a negative WLA. .This will
typically occur where the background
concentration of pollutants exceeds
'criteria levels, and the point source uses
the receiving water as its source of
intake water. Where the formula^. •
generates a negative WLA, a discharge ;
which has the reasonable-.potential to
cause or contribute to an excursion
above a criterion or value cannot be
allowed unless a multiple-source TMDL
is prepared that will ensure attainment
of water quality standards,.
e Pollutant Degradation. Alt&ough
pollutant degradation may be
considered for different purposes under
Options A andB, both.Options allow
TMDLs to account for degradation of a
pollutant provided two conditions are
met. The first condition is that the
regulatory authority must have
information regarding, the rate of
degradation of the pollutant in the form
of field studies or other relevant
information. Field studies, if used, must
document that degradation, of the
pollutant will occur under the full range
of critical conditions exriected to be ••-'.
encountered, and should quantify the
degradation. Critical conditions should
include the design conditions that are
established for the implementation of
criteria in ambient waters as well as
other conditions such as periods of
stratification Of the water body and
variability of the facility effluent flow
rate. If field study information is not
available, the regulatory authority can
- use other relevant information such as .
literature references from similar sites.
Regardless of the type of information
used, all information must be reviewed
by the regulatory authority and found to
be scientifically valid, EPA invites
specific comment on what type of
; information is sufficient to demonstrate
degradation in ambient waters, and in
particular, whether literature
information or field data from similar
sites can be used, to quantify
degradation. , . ...
The second condition is that.the.
studies take into account factors other '
than, pollutant degradation that affect
the concentration of the pollutant in the
water column including but not limited
to resuspension of sediments, speciation
and transformation.
' The Steering Committee
recommended" including a requirement
that the degradation in the mixing zone
must be rapid and significant. EPA is
not proposing these requirements today
since these terms are vague and since
any degradation that does occur in. the
mixing zone will in practice be rapid
due to the relatively small size of the
mixing zones; Further,EPA does not
believe that the degradation need be
significant, but rather that the permittee
be allowed to receive consideration for
any degradation that can. be
demonstrated to occur, in the mixing
zone.
The Steering Committee
recommended,that the Guidance specify
, that losses from the water column due
to physical transfer of pollutants to
other media is not an acceptable
environmental fate process for
increasing TMDL allocations. The
Steeling Committee was concerned .that
inter-media transfers, including
volatilization (evaporation from the
water to the, atmosphere},
bioaccumulation In the .tissues of
organisms and sorption to sediment and
suspended solids in the water body may
not be permanent losses and that
pollutants could be reintroducect into
the water column at some later time
EFA is not proposing,these
requirements today, however, because
EPA believes that the concerns of the
Steering Committee can be answered
through other mechanisms.
Each of the Great Lakes States has" ".
already adapted a narrative criterion
specifying that waters shall be free from
pollutants that settle to form
objectionable deposits. EPA's existing
NPDES requirements (40 CFR 122.44(d))
require permit effluent limitations to
meet these narrative criteria. Each
option also contains identical text in
general condition 6 requiring that
TMDLs prevent the accumulation of
pollutants in sediments to levels'
injurious to designated or existing uses.
Inclusion of this provision in the
proposed Guidance reflects EPA's
concern about sediment quality in the
Great Lakes System and a recognition
that ft may often need to be considered.
,EPA is currently developing new
methods for preventing sediment
contamination. The first step is to
develop numeric sediment criteria
guidance. Upon State adoption of-
sediment criteria as part of a State WQ.S,
regulatory authorities will need to factor
such criteria into the TMDL and NPDES
permitting-process.
To the extent that volatilization does
not represent a permanent loss from the,
Great Lakes System, it will be accounted
for in determining background „
concentrations. Accordingly, it does not
seem necessary to prohibit accounting
; for volatilization in establishing TMDLs.
It would be extremely difficult to
establish a significant loss of ambient
pollutaiits as a result of .
bioaccumulation. Since most TMDLs
assume steady state conditions, it
should also be assumed that the aquatic
biota is at equilibrium regarding
pollutant uptake and depuration.
Likewise, thepotentialloss of .
pollutants from the water column by
bioaccumulation into fish tissue is offset
by the return of pollutants via
depuration in more complete models.
Again, the regulatory authority has
available a more appropriate mechanism
for addressing physical transport.
Finally, EPA believes that pollutant
volatilization is an irreversible loss of ,
pollutants from water column. EPA
recognizes that allowing discharge of •
volatile pollutants may lead to elevated
pollutant concentrations in the air, ' .
However, EPA believes that these , .
potential releases are better controlled
using other statutory authorities, for
example, the Clean Air Act. EPA invites
comment on whether some or all - *
physical transport processes should be
precluded from consideration in. the
development ofTMDLs and WLAs. ,
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8. Pollution Trading Opportunities
The TMDL process provides an
opportunity for pollution trading in the
water quality program as long as CWA
goals and requirements are met. Effluent
limits and nonpoint source controls, for
example, must be designed, maintained
and enforced so that water quality
standards and other program
requirements are met. For purposes of
the proposed Guidance, trading refers to
approaches which introduce market
incentives into water quality control
decisions by acknowledging the ability
of a point source to achieve water
quality basod loading reductions
through creative, enforceable, market
mechanisms.
Tho proposed Guidance allows States
to look for pollution trading
opportunities as TMDLs are established.
It should be noted, however, that some
of the general conditions of applicability
in both Options may limit trading
opportunities since they specify, for
example, that mixing zones for BCC
discharges must be eliminated within 10
years and focus primarily on developing
TMDLs necessary to derive point source
permit limits. These types of conditions
may serve to define the characteristics
of trading programs acceptable within
any given basin of the Great Lakes
System.
While the proposed Guidance focuses
primarily on providing two options
designed to provide consistent TMDL
procedures among the States, each
option does provide general guidance
for completing TMDLs on varying
geographic scales. TMDLs completed for
larger geographic areas are generally
moro complex and deal with pollution
from point and nonpoint sources. As the
number of sources and pollutants
included in a TMDL and the geographic
area grows larger, opportunities for
trading and the types of trading
programs appropriate to specific sites
and water quality problems will grow.
9, State Adoption
In order to achieve consistent
application of the TMDL procedures,
the proposed Guidance would require
States to adopt a TMDL procedure
consistent with procedure 3 of the final
Guidance, or an equally stringent
alternative. If a State chooses to adopt
an alternative approach, the selected
approach must result in equal or more
stringent controls than the final
procedure 3.
10. Summary of Other Options
Considered
Earlier drafts of procedure 3 focused
only on tha development of WLAs for
point sources using predominantly
Option B. One State, New York, uses a
different TMDL procedure from the
other Great Lakes States. During the
Technical Work Group sessions it
became evident that these approaches
differed in respect to establishing
TMDLs for tributaries and in the general
level of detail and assumptions used.
The Steering Gommittee, believing that
both approaches may be consistent with
National guidance and the GLWQA,
decided to propose both approaches as
options and to request comment on
them.
Additionally, the Steering Committee
considered whether, based upon
demonstrations that the effluent rapidly
mixes with the receiving water, the
regulatory authorities should have the
flexibility to specify effluent limitations
based upon acute aquatic life criteria
which are greater than the FAV. These
demonstrations would define the'acute
mixing zones, which are also known ag
zones of initial dilutions (ZIDs) and
areas of initial mixing (AIMs). As
.explained earlier in the preamble,
Option B restricts the WLA for the
control of acute toxicity to not greater
than the FAV, while Option A provides
for case-by-case determinations and
applications of State-developed acute
mixing zone policies in deriving WLAs
necessary to prevent acute toxicity. EPA
would like to receive comments on the
relative merits of the two approaches.
The Technical Work Group had
recommended that Option B prohibit
mixing zones from extending from a
tributary into a lake or connecting
channel. The prohibition was intended
to ensure that additional mixing based
upon the dilution from OWGLs or
CCGLs would not be incorporated into
the WLA development. EPA was
concerned that this prohibition could
result in an inequitable elimination of
mixing zones for sources located at the
mouths of tributaries. Accordingly, this
language was deleted from the proposed
Guidance and replaced with a condition
in section D.2 of procedure 3B requiring
that when information on mixing zones
is available for a point source discharge •
that demonstrates that the mixing zone
extends into an OWGL or CCGL, the
WLA is determined using the more
stringent dilution allowance provided in
either section C.I or section D.S.c. States
will use professional judgement in
assessing when a mixing zone extends
beyond the boundary of the tributary
basin. EPA solicits comments on
whether this revision to the
recommendation of the Technical Work
Group is appropriate and, if not,
alternative proposals for dealing with
discharges at the mouth of tributaries.
11. Request for Comments
Comments are invited on all aspects
of the two proposals for TMDL
development and on possible
alternatives, EPA is interested in
receiving comments individually on
both Options A and B. Area's in which
EPA is particularly interested in
receiving comments include the overall
technical and programmatic approach
set out in each option, the technical
issues involved in applying each option
to a varied set of water quality
problems, consistency with existing
national policy and program approaches
and the degree to which each option
allows for integrated development of
effective point and nonpoint source
controls. In addition to comments on
each option, EPA is also interested in
receiving comments on the consistency
between Options A and B. EPA is
particularly interested in receiving
comments concerning the overall
compatibility, technical and
programmatic strength? and weaknesses
of each option. EPA is particularly
interested in the potential impact that
any differences in these options might
have on the perceptions and interest of
the public and regulated community.
Comments are also invited on how the
options should be incorporated into the
final implementation procedures. EPA
is very interested in receiving comments
which address the compatibility of these
two options. Should, for example, all
the States in the Great Lakes System be
required to adopt either Option A or B,
or a combined approach so that only
one consistent approach is employed
throughout the Great Lakes System. Or,
alternatively, should States be required
to adopt one or the other of these
options so that all the States in the Great
Lakes basin are committed to using
either Option A or B. Finally, should
States be permitted to use one or the
other option according to the situation
at hand. EPA also solicits comments on
the option of not providing specific
TMDL provisions in the final Great
Lakes Guidance, relying instead on a
continuation of the existing national
program in this area.
•EPA would like to receive comments
on the elimination of mixing zones for
BCCs. In addition, EPA welcomes
comments on whether the lO^year
implementation period is reasonable
and if other periods are more
appropriate.
EPA would also like comments from
the public on whether acute mixing-
zones should be allowed and if so,
whether the Guidance should include
any maximum size for acute mixing
zones, and what that size should be.
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20939
Further, EPA would like comments on
the need for, and applicability o£. a final
effluent cap,, such, as the Final Acute
Value which is proposed in Option B,
EPA invites comment on the
procedures to account for the
environmental fate of pollutants;, .
including: the requirement for tiia
permittee to submit documentation on
the rate of degradation inside the mixing
zone; allowing field studies based on a
similar stream anda similar discharge to
be considered acceptable and the
information to be submitted by the ,
permittee. ,
EPA also invites comments on the
provisions related to background data
requirements, specifically on how
background is defined and on including
caged fish tissue andloading data as
acceptable available data. EPA also
invites comment on the requirement
that the'background concentrations be
representative and on providing1 .
relatively Iittle,detail in the h
methodology regarding determination of
what is representative, or on how to
adjust data to make it representative.
The public is also invited to comment
on setting data points below the
detection level to one-half of the ,
reported detection level for the purposes
of calculating a geometric mean;: setting
data points between the detection level
and the quantification level at the mid-
point between f&& twa reported! levels;
and setting the background level as zero-
when all data are below the level of
detection. ;
It is EPA's intent that the Great Lakes
States will, at a minimum, use this
procedure for developing TMDLs for all
pollutants except those identified in
Table 5,of the proposed Guidance. The
results of'dynamic modeling may be
used only where the results can be
shown to be more restrictive thaii the
results due to the steady-state \ •
assumptions of both options in.
proposed procedure 3. EPA would like
comments on whether the States should
be allowed to use the results of dynamic
modeling whether the results are less
stringent or not when compared with
the results using the steady-state
approaches in procedure 3.
Finally, cominenters may provide
additional information or alternative
approaches to TMBL development. In
particular, EPA welcomes comments on
means for controlling nonpoint sources,
D. Additivity •
1. Introduction
* Traditionally* EPA has developed ••-
numerical criteria on a single pollutant
basis. However, many instances of
contamination in surface waters involve
mixtures of two or more pollutants.
Such mixtures can interact in various
ways which may affect the magnitude
and nature of risks or effects on human .
health, aquatic life and wildlife. With
respect to impacts on aquatic life, the
interactive'effects of discharged
pollutants on organisms is ascertained
through direct exposure of test ,
organisms to a point source effluent in
whole effluent toxicity (WET) tests as
described in procedure 6 of appendix F
of the proposed Guidance, The use of
such tests to determine additive
pollutant effects on aquatic organisms is
a well-established .component of
existing Clean Water Act regulatory
programs, EPA currently has no
guidance regarding consideration of
additive effects of pollutants on
wildlife.
EPA has considered-mechanisms for .
assessing effects resulting from human
exposure to pollutant mixtures. On
September 24,1986, the EPA published
"Guidelines for the Health Risk
Assessment of Chemical Mixtures C51
, FR 34O14D," which is available in the
administrative record feir this
rulemaking. These guidelines set forth
principles and procedures for human
health risk assessment/of chemical .
mixtures. Although the calculation ."
procedures ia these guidelines differ for
carcinogenic and non-carcinogenic'
effects, both procedures assume dose
additfvity in the absence of information
' on specific mixtures. Dose additivity is
based on the assumption that the --
components in a mixture hava the same
mode of action and elicit titts same types
of effects. Because information on the
interaction of pollutants and on the
modes of action, is so sparse, EPAt
recommends in the 1386 guidelines that
risk assessments of mixtures be based :
on an assumption! of additivity, as long
as the components elicit similar effects.
Dose additivity could result im errors in
risk estimates if synergistic or
antagonistic interactions occur ft.e»,
additivity assumptions could result in
overestimates or underestimates of the
actual, risks); Thus, the assumption is
not a "worst-case" assumption, but a
reasonable assumption within the
bounds of possibility when specific
information on pollutant interaction is
not available.
In an effort to address the concurrent
human exposure to combinations1 of
carcinogens, three Great Lakes States
(Illinois, Minnesota and Wisconsin}
assum® ia criteria development that the
risk of a combination pfcarcinogens in
a mixture is equal to the sum of risks
associated with exposure to each
' individual pollutant in the mixture.
These three States have adopted an.
acceptable cancer risk level of 10~5 for
exposures to individual pollutants. In
Minnesota and Wisconsin, the total
risks associated with exposure to ,
mixtures is aot to- exceed 1&~5 while
Illinois allows a total cancer risk level
of 10'""* for exposure to mixtures. • •'
"The Great Lakes Water Quality * . :
Agreement addresses this issue in
Annex 12t which states that "The
Parties shall establish action levels to
protect humaa health based on_ v
multimedia exposure and the interactive
effect of toxic substances. ** In addition,
Annex 12 of the Agreement
recommends that research efforts on the
, interactive effects of residues of toxic
substances om aquatic life, wildlife, and
human health be intensified. A
supplement to Annex 1 of the
Agreement also provides for the /
development of specific'objectives
addressing synergisiic and additive
effects of pollutants,
2. Approaches Considered
The Committees of tfaalaitiative .
sought to develop a consistent approach
to additivity within the Great Lakes
States. Their deliberations resulted in
proposals for the use of sdditivity for
the .protection of aquaticHfe, wildlife =
and human health. EPA evaluated the-
Committees' proposals as well as other
alternatives; both the Committees*
proposals arid alternatives are discussed
below.
EPA's traditional approach is to
address each pollutant OH an individual
basis in the derivation of criteria; and
values. However, EPA has provided V:
guidanqs in the past on how to take —
.additivity into account for the
protection of aqtiatic life and human
health. With respect to the proposed
Great Lakes Water QualityGuidance,
EPA mvites comment on. the additivity-
relatedissues discussed below and on
whether a specific procedure, should be
either required or set forth as guidance-
irt the final rule.
a. Aquatic lAfel As proposed by the
Committees of the Eiitiative, the
proposed Guidance accounts for
additive effects on aquatic life through
establishment of whole-effluent toxieity
(\VETJ limitations, WET requirements
are proposed under procedure ® of
appendix F of the proposed GuMancev
• b. Human Health—Carcinogens. For .-
carcinogenic effects on. humam health,
the 1986 guidelines for mixture >
recommend that in, the absence of
contrary information: it be assumed that
the total cancer risk posed by a mixture
of chemicals is the sum of risks: posed
by exposures to individual chemicals.
Since information on the interaction ./f
pollutants in a mixture is generally
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Federal Register / Vol. 58, No, 72 / Friday, April 16, 1993 / Proposed Rules
rather limited, the 1986 guidelines
recommend the use of the additivity
assumption under most circumstances.
However, the guidelines indicate a
preference for relying on actual data on
the interaction or pollutants in mixtures
whenever adequate data are available.
Therefore, EPA recommends that in
those cases where it can he
demonstrated that the carcinogenic risks
of a mixture are not additive, the
additivity assumption should not be
used.
In its December 16,1992, report,
"Evaluation of the Guidance for the
Great Lakes Water Quality Initiative,"
the EPA's Science Advisory Board
(SAB) stated that additivity should not
ba used as a default, hut rather multiple
carcinogens should he considered on a
casa-by-case basis. This is because
additivity assumes a common
mechanism of action and carcinogens
ore known to act by a. wide variety of
mechanisms and to target different
organs. The SAB report goes on to say
that for compounds that act at the same
receptor (such as dioxin, fuians and
PCBs) an assumption of additivity might
well b« defensible. EPA invites
comment on whether the assumption of
additivity for carcinogens should be
limited to those situations when
adequate data are available on the
mechanisms of action,
EPA invites comment on whether the
narrative criteria of the States and
Tribes providing that waters be free
from substances that injure or are toxic
to humans, animals or plants should be
Interpreted to account for the additive
offsets of chemicals. The purpose of this
approach would be to prevent the total
risk associated with carcinogens in
ambient waters from exceeding a non-
appreciable level. As discussed
elsewhere in the proposed Guidance,
EPA is proposing criteria/values for
single pollutants based on a 10~5 cancer
risk lovel, EPA believes that the use of
a risk level on total risk associated with
chemical mixtures would enhance
protection of human health, and
consistency in addressing additive
impacts throughout the Great Lakes
System. It would also be consistent with
tb.8 provisions of the Great Lakes Water
Quality Agreement calling for
consideration of the interactive effects
of toxic substances. Insofar as it may
require greater reductions of pollutant
discharges than would be required
through implementation of individual
chemical criteria alone, it would also
further the "virtual elimination" goal of
the Agreement. EPA requests comments
on the possible use of 10~s as a cap on
tho cancer risk associated with mixtures
and on alternative risk levels (e.g., 10-*}
that may be considered. A specific •
option that would require interpretation
of narrative criteria to establish a 10~5
cap on cancer risk associated with
chemical mixtures is set forth in section
3 of this preamble discussion.
EPA also requests comments on
whether -the additivity concept should
be applied only to a limited (i.e., finite)
number of the carcinogens in ambient
waters that individually pose the
greatest cancer risk to exposed
populations rather than to all detected
carcinogens. For example, the narrative
criteria could be interpreted such that •
the cumulative cancer risk posed by the
presence of five (or some other number
of) carcinogens in any given waterbody
or segment would not exceed 10~s.
Such a modification would reflect the
fact, recognized in EPA's 1986
Guidelines for the Health Risk
Assessment of Chemical Mixtures, that
as the number of pollutants covered by
the additivity assumption increases, the
uncertainty associated with the
resulting risk assessment is also likely to
increase. This approach could also
greatly ease the administrative burden
of preparing total maximum daily loads
(TMDLs) and water quality-based
effluent limits (WQBELs) based on the
additivity assumption, since it would
provide a cut-off to what otherwise
might be an extended inquiry and
would relieve regulatory authorities of
the burden of identifying risks and
sources associated .with carcinogens that
pose a relatively insignificant risk to
human health. Finally, EPA requests
comments on whether a separate water
quality criterion (WQC) should be
established for carcinogenicity (e.g.,
total cancer risk for ambient waters not
to exceed 10 ~4,10 ~5, or some other
cancer risk level) rather than the
approach discussed above for
implementing narrative criteria.
These alternatives differ considerably
from the proposal of the Committees of
the Initiative with respect to considering
additivity for carcinogens. The
Committees proposed that the additivity
assumption be applied only with
respect to facilities otherwise requiring
WQBELs for individual carcinogens,
and only as to those carcinogens
requiring WQBELs. Thus, the
Committees did not propose application
of the additivity assumption in setting
or interpreting ambient water quality
criteria. Rather, their proposed approach
would have resulted in further
limitations beyond WQBEL levels so
that the carcinogens covered by
WQBELs from a given facility would
not, after mixing with receiving waters,
represent a total cancer risk greater than
10 ~s. Thus, the Committees' approach
did not address Carcinogens for which
WQBELs were not needed. In addition,
because not all sources discharging a
pollutant for which WQBELs are needed
necessarily need WQBELs in order to
provide for attainment of water quality
standards, not all sources discharging a
given carcinogen would have the
additivity assumption applied to their
discharges.
Although EPA agrees that the '
approach proposed by the Committees
of the Initiative offers certain
administrative advantages as compared
with other alternatives, EPA is
concerned that the Committees'
approach could be inequitable in its
application. The full text of the proposal
of the Committees is reproduced below
under section 4 of this preamble. EPA
invites comment on the possible use of
that approach in the final rule to .
account for the additive effects of
carcinogens in the Great Lakes.
c. Human Health—Non-carcinogens.
The 1986 EPA guidelines on chemical
mixtures acknowledge that additivity of
effects for non-carcinogens is most
appropriate when pollutants in a
mixture elicit the same type of effect by
the same mechanism of action. •
However, because information, on the
mechanism of action is rather limited
for many pollutants, the 1986 EPA
guidelines on chemical mixtures
recommend that when two or more
compounds produce adverse effects on
the same organ system (i.e., target organ)
the effects should be considered
additive. The 1986 guidelines
additionally state that additivity for
dissimilar effects does not have strong
scientific support. Thus, the underlying
assumption in the 1986 guidelines is
that the components of a mixture whick
produces adverse effects on the same
target organ are additive. This approach
could overestimate or underestimate the
actual risks due to possible antagonistic
or synergistic'interactions among
components in a mixture.
The 1986 guidelines recommend the ,
use of a hazard index (HI) approach for
non-carcinogenic toxic agents. The
hazard index indicates if there is a
concern with a mixture by providing a
rough measure of likely toxicity.
However, it does not define dose-
response relationships (i.e., its
numerical value is not a direct estimate
of risk).
EPA solicits comment on the HI
approach for applying additivity to non-
carcinogenic effects, as described in the
1986 guidelines. This approach assumes
that multiple, simultaneous exposures
to a chemical could result in an adverse
health effect and that the magnitude of
the effect is proportional to the sum of -
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20941
the ratios of the* actual exposures to
"acceptable" exposures. When the HI
exceeds unity (i.e., 1) a potential, for
adverse health effects exists. While any
single chemical with an exposure- level
greater than the toxicity value (i.e., .
threshold or Reference dose (RfD)) will
cause the HI to exceed unity, for
mixtures, the HI can also exceed unity
even' if no single chemical exceeds its
RfD. , •'"-'.;•'
The hazard index approach assumes
dose addition for those compounds that
induce the same target organ response -
and, therefore, a separate hazard index
should he developed for each end point.
Dose addition (additivity) for dissimilar
effects does not have strong scientific
support. For estimating the "HI" of a
mixture of non-carcinogens based on
additivity, the following equation may
be applied:
HI
- EI i
E
RfD
1 t
Where, for i = 1 through n:
EI = exposure level of the chemical in
the mixture.
RfDi = The Reference dose for that
chemical.
: Since publication of the 1986
guidelines, EPA has published a
"Technical Support Document on Risk
Assessment of Qiemical Mixtures
(November 1988)", which discusses the .
hazard index approach as well as an
alternative "toxicity equivalency factor"
' (TEF) approach. This document is
available in the administrative record
for this rulemaking. The "toxicity'
equivalency factor" approach was not
discussed in the 1986 guidelines but has
since been recommended by EPA for
risk assessment of certain chemical
classes.: One advantage of the TEF
approach is that it allows the use of data -
to assess and quantify the toxicity of
mixtures that are not used to quantify
the risk from exposure to single ; ,
chemicals (lie.,- acute data, data from
atypical routes of environmental
exposure and in vitro data). The 1988
Technical Support Document states that
the TEF approach should be applied;
only to compounds that have the same
mode of action or act independently. ;.
The approach described in the 1988
, Technical Support Document is more,
restrictive than the 1986 guidelines in
the use pf the additivity assumption for
non-carcinogens but it is consistent with-
the proposal for the use of TEFs made
by the Committees of the' Initiative. EPA
also believes that the approach in the
1988 Technical Support Document is
not inconsistent with the original 1986
guidelines which state: "No single '
approach can be recommended to risk
assessments for multiple chemical
exposures."
The preferred approach presented in
the 1986 guidelines for conducting risk
assessment of mixtures is to use in vivo
toxicity data on the mixture itself based
on the route of exposure and duration
period of concern. However, this
approach is not practical in most cases .-.
because adequate toxicity data are
available on very few complex mixtures.
The "toxicity equivalency factor"
approach involves estimating the
potency of less well-studied
components in a mixture relative to the
potency of better studied components,.
using data from comparable types of in
vitro and short-term in vivo assays. So
far, this approach has been used only to
estimate the toxicity of mixtures of
chlorinated dioxins and dibenzofurans
by using extensive data on the in vitro
activity of these compounds. Today's
proposal requests .comments on whether
EPA should consider the "toxicity
equivalency factor" approach for these
chemical classes and for any other , .
mixtures for which TEFs may
reasonably be calculated in the future as
this area of research progresses and EPA
is able to develop additional TEFs.
EPA specifically solicits comment on
two possible approaches to addressing
additivity for non-carcinogens, set forth
. in sections 3'and 4 of this preamble.
Both would require that mixture of
CDDs and GDFs be considered additive,
in accordance with specific TEFs
described in more detail in section 2.d.
of the preamble. In addition, the option
described in section 3 would require use
of bioaccumulation equivalency factors
(BEFs) (discussed in detail below) to
account for differences in
bioaccumulation potential of different
CDDs and CDFs. The alternative set
forth in section 3 would require
generally that noncancereffects.be
considered additive for those pollutants
for which available scientific •' •
information supports a reasonable
assumption that the pollutants produce
the same adverse effects through the
same mode of action, and for which
TEFs and BEFs may reasonably, be
calculated. Thus, this option would
establish a general requirement for
States and Tribes to develop specific
additivity protocols for classes of
pollutants when sufficiently supported
by scientific information.
The second option which EPA
specifically solicits comment on is set ,
forth in section 4. It would require
application of additivity assumptions ,
only -for those pollutants for which TEFs
are set forth as part of the Great Lakes
Guidance. Pollutants covered initially
would include CDDs and CDFs, but
more pollutants could be addressed
through future revisions to die rule.'
This option would best promote •
consistency among the Great Lakes
States and Tribes, but may involve more
lag time between availability of
scientific, support for application of •
additivity-and use in water quality
management than would ike option set
forth in section 3. • •
d. TEFs and BEFs for Chlorinated
Dibenzo-p-dioxins (CDDs) and
Chlorinated Dibenzofurans (CDFs).
Chlorinated dibenzo-p-dioxiris and
dib~ehzofurans (CDDs/CDFs) constitute a:
family of 210 structurally related
chemical compounds. During the late
1970s and early 1980s, EPA
encountered a number of incidents of ',
environmental pollution in which the
toxic potential of CDDs and CDFs
figured prominently. Initially, concern
was focused solely on 2,3,7,8-TCDD,
which was produced as a low level by-
product during the manufacture of
certain herbicides.
During the past 20 years, many
studies have been conducted to '
elucidate the toxic effects of 2,3,7,8--
TCDD. The data obtained from these
studies are summarized in a number of
reviews (U.S. EPA, 1984; U.S. EPA,
1985; U.S. EPA, 1988; WHO, 1977;
NRCC, 1981), which are available in the
administrative record for this"
rulemaking. EPA is currently engaged in
a major effort to generate more data on
dioxih toxicity, and to update its :
analysis of existing data. While research
efforts to date have not answered all of,
the questions, the data do show that
2,3,7,8-TCDD can prbduce a variety of
toxic effects, including cancer and
reproductive effects in .laboratory
animals at very low doses. : . •
Data on the toxicity of other CDDs and
for CDFs is considerably more limited.
These data are summarized in two EPA
documents entitled "Interim Procedures
for Estimating Risks Associated with .
Exposures to Mixtures of Chlorinated
Dibenzo-p-Dioxins and -Dibenzofurans
(CDDs and CDFs)", (October 1986), and
"1989 Update to'the Interim Procedures
for Estimating Risks Associated with
Exposures to Mixtures of Chlorinated
Dibenzo-p-Dioxins and -Dibenzofurans.
(CDDs and CDFs)", (March 1989) {the
"1989 TEF Update"), which are
available in, the, administrative record •
for this rulemaking. While data
available from long-term in vivo studies
are limited for the majority of CDDs and
CDFs, a much larger body of data is '.'.,
available on short-term in vivo studies
and a variety of in vitro studies. These
experiments cover a wide variety of end
points; e.g.,. developmental toxicity, cell
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
transformation, and enzyme induction
(aryl hydrocarbon hydroxylase [AHH]).
While the doses necessaiy to'elicit the
toxic response differ in each case, the
relative potency of the different
compounds compared to 2,3,7,8-TCDD
Is generally consistent from one end
point to another.
This information, developed by
researchers in several laboratories
around the world, reveals a strong
structure-activity relationship between
tho chemical structure of a particular
ODD or CDF congener and its ability to
elicit a biological or toxic response in
various in vivo and in vitro test systems,
(Bandiera et al., 1984; Olson et at, 1989;
U.S. EPA 1989; NATO/CCMS 1988a,b).
Research has also revealed a
mechanistic basis for these observations.
That is, a necessary (but not sufficient)
condition for expression of much of the
toxiciU' of a given CDD or CDF congener
Is its ability to bind with a particular
protein receptor located hi the
cytoplasm of the cell. This congener
receptor complex then migrates to the
nucleus of the cell, where it initiates
reaction loading to expression of
toxidty (Poland and Knutson, 1982).
Based on this type of Information,
scientists suggested the development of
numerical factors ("toxic equivalency
factors" or "TEFs") that could be used
to equate the toxicity posed by various
CDDs and CDFs to 2,3,7,8-TCDD for
purposes of conducting risk assessments
including mixtures of the chemicals.
EPA developed an Interim procedure
that was reviewed and approved by
EPA's Science Advisory Board, and
published as a monograph of EPA's Risk
Assessment Forum in 1987. The
procedure was modified in certain
respects in the 1989 TEF Update, and
has been adopted for international use
by the North Atlantic Treaty
Organization.
EPA solicits comment on whether
EPA should require use of the specified
TEF-based approach to equate mixtures
of CDDs and CDFs to a concentration of
2,3,7,8-TCDD for purposes of
implementing the human health and
wildlife criteria for 2,3,7,8-TCDD.
Specific options are set forth in sections
3 and 4 of this preamble. The TEFs are
tho samoas those set forth in EPA's
1989 TEF Update, and that Update
provides the technical basis for the
proposal. EPA also invites comment on
whether other TEFs should be used
rather than those listed in the 1989 TEF
Update.
The CDD/CDF TEFs address the
toxicity of various chemicals as
compared to 2,3,7,8-TCDD, but do not
address differences in bioaccumulation
potential between the chemicals.
Because the criteria for 2,3,7,8-TCDD are
largely driven by the relatively large
bioaccumulation factor for the chemical,
and because available information
suggests that other CDDs and CDFs have
different bioaccumulation factors, EPA
believes that it may be appropriate to
use factors accounting for the different
BAFs in converting concentrations of
CDDs and CDFs to equivalent
concentrations of 2,3,7,8-TCDD. The
option set forth in section 3 incorporates
this approach. The technical rationale
for the particular "bioaccumulation
equivalency factors" (BEFs) selected is
provided in a "Draft Technical Support
Document for Bioaccumulation
Equivalency Factors," which is
available in the administrative record :
for this rulemaking.
The Committees of the Initiative did .
not propose use of bioaccumulation
equivalency factors; their proposal
would have assumed that BAFs for all
CDDs and CDFs are identical to that
calculated for 2,3,7,8-TCDD. Because
available information on BAFs for other
CDDs and CDFs suggests that BAFs for
those chemicals are generally smaller
than for 2,3,7,8-TCDD, the Committee's
proposal would be a conservative, as
well as a simplifying, approach. EPA
solicits comment on this option, set
forth in section 4 of this preamble.
e. Wildlife. As stated earlier, EPA has
no present policy on the use of
additivity for wildlife effects. EPA
solicits comment, however, on whether
additivity with respect to wildlife
effects should be treated in a manner
consistent with the options described '
above for noncancer human health
effects and for mixtures of CDDs and
CDFs. EPA believes that an argument
can be made that the TEFs for CDDs and
CDFs developed for use in human
health risk assessments should generally
be applicable to wildlife, since the TEFs
are based largely on animal studies.
Using the TEF approach, the total
allowed exposure level for mixtures of
these congeners would not exceed the
level established by the wildlife criteria
for 2,3,7,8-TCDD, based on 2,3,7,8-
TCDD equivalents. Two specific
alternatives regarding application of
additivity principles to wildlife effects
are set forth in sections 3 and 4 of this
preamble. EPA requests comment on
these options, and on possible
alternatives to them.
In developing this proposed
Guidance, the use of TEFs for
polychlorinated biphenyls (PCS)
congeners for wildlife was considered.
In December 1990, EPA's Risk
Assessment Forum held a workshop to
specifically address the use of TEFs for
PCBs (Risk Assessment Forum,
Workshop Report on Toxicity
Equivalency Factors for Polychlorinated
Biphenyl Congeners, June 1991, EPA/
625/3-91-020). This workshop
concluded that the application of TEFs
to PCBs is not as straightforward as it is
in the case of GDDs and CDFs, but that
TEFs for dioxin-like PCB congeners are
feasible and may be considered additive
with those for CDDs and CDFs. Further,
the workshop concluded that current
dioxin-like TEFs appear to be useful in
assessing traditional measures of
wildlife toxicity. The workshop, •
however, recommended that a TEF
scheme for PCBs should be seen as an '
interim procedure and promising
bioassay approaches should also be
vigorously pursued.
On March 19-20,1992, a Dioxin
Ecotpx Subcommittee of the Ecological
Processes and Effects Committee of the
Science Advisory Board met to review
EPA's research proposals to support the
development of an ambient aquatic liie
water quality criterion for 2,3,7,8-
TCDD. At that meeting, the
Subcommittee addressed the general
issue of research needed to support the
use of TEFs for aquatic life and wildlife.
In their final report dated August 1992,
the Committee stated that the TEF
approach appears promising for aquatic
life and wildlife but more studies are
needed to show phylogenetic
variability. The Committee concluded
that at the present time there are
insufficient data available to judge the
reliability and the accuracy of the TEF
approach. .
A recent study of the potencies of
CDDs, CDFs and PCBs relative to
2,3,7,8-TCDD for producing early life
stage mortality in rainbow trout
calculated TEFs for each of these classes
of chemicals (Walker and Peterson,
1991). The TEFs calculated in this study
for CDDs and CDFs were similar to
those proposed by Safe (1990),
However, the TEFs for the PCB
congeners were 14 to 80 times less than
those proposed in Safe (1990), The
results of the Walker and Peterson study
illustrate the significant uncertainties in
applying TEFs across species and
endpoints for PCB congeners. Further,
another recent study concluded that the
TEFs proposed in Safe (1990) for the
"dioxin-like" PCBs overestimate the '.
potency of these compounds by a factor
of 10-1,000 (DeVito et al., 1992).
EPA solicits comments on whether
TEFs for PCBs should be included
together with those for CDDs and CDFs
in the use of the additivity concept for .
wildlife effects. Table VDI.D-1 presents
TEFs for PCB congeners from Safe.
1990. EPA specifically requests
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Federal Register /-Vol. 58>
1G, 1993 '/ Imposed faiJes 20943
comment on the inclusion of these TEFs
for wildlife in the Great Lakes Guidance..
TABLE VIII.D-1.—Toxic EQUIVALENCY
FACTOR VALUES FOR PCBs
(a) Coplanar PCBs:
-3,3',4,4',5-PeCB .....
3,3',4,4',5,5'-HxCB .......
3 3',4,4'-TCB
(b) Monoortho Coplanar
PCBs:
• 233'44'-PeCB
234 4'-PeCB
2' 3 4 4' 5-PeCB
,2,3',4,4',5-PeCB
2,3,3',4,4',5-HxCB
2,3,3',4,4',5-HxCB ........
2,3',4,4',5,5'-HxCB .......
2,3,3',4,4',5,5'-HpCB ....
'IUPAC
•..#'
126
169
. 77
105
114
< 123
118
156
157
167
189
TEF
Value
0.1
.05
.01
.001
.001
.001
.001
.001
.001
.001
.001
3. Request for Comment on Approach
Considered for Implementing the States'
Narrative Criteria
The text presented below represents
one approach that would specify that '
the narrative criteria be interpreted to
account for the additive effects of '
chemicals. EPA requests comments on
whether the language below should be
added to the Implementation
Procedures of the final Guidance,
- The following procedures establish the
manner in which the additive effects of
chemical mixtures shall be treated when
interpreting the narrative criteria of the States
and Tribes requiring that all waters be. free
from substances that injure or are toxic or ,
produce adverse physiological responses in •
humans, animals or plants. ,
A. Aquatic Life Effects. Whole-effluent
toxicity requirements established under
procedure'6-of appendix F of part 132 shall
be used to account for additive effects to
aquatic organisms.
B. Wildlife Effects. The effects of
individual pollutants shall be considered ;
additive for chlorinated dibenzo-p-dioxins
and chlorinated dibenzofurans, and for other
pollutants for which available scientific
information Supports a reasonable
assumption that the pollutants produce the
same adverse effects through the same
mechanism of action, and for which toxic
equivalency factors and bioaccumulation
equivalency factors may reasonably be
calculated. For chlorinated dibenzo-p-
dioxins and chlorinated dibenzofurans,
additivity shall be accounted for hi
accordance with section E. For other
pollutants, toxic equivalency factors and
bioaccumulation equivalency factors shall he
developed and thereafter applied in a manner
. similar to that described in section E based
either on a relationship to 2,3,7,8-TCDD or to
some other chemical, as appropriate.
C. Human Health—Non-cancer Effects.
The effects of individual pollutants shall be
considered additive for chlorinated dibenzo-
p-dioxins and chlorinated dibenzofurans,
and for other pollutants for which available
scientific information supports a reasonable
assumption that the pollutants produce the
same adverse effects through the same
mechanisnl of action, and for which toxic
equivalency factors and bioaccumulation
equivalency factors may reasonably be
calculated. For chlorinated diberizo-p-
dioxins and chlorinated dibenzofurans,
additivity shall be accounted for in ,
accordance with section E. For other
pollutants, toxic equivalency factors and
bioaccumulation equivalency factors shall be
developed and thereafter applied hi a manner
similar to that described hi section E based
either on a relationship to 2,3,7,8-TCDD or to
some other chemical, as appropriate.
D. Human Health—Cancer Effects. The
incremental cancer risk of each carcinogen
shall be considered to be additive and the,
total cancer risk shall not exceed 10~5,
However, the State or Tribe may determine,
based on information submitted by a
permittee or otherwise available to the State
Or Tribe, that the carcinogenic risk for a given
mixture is not additive.
E. Toxicity Equivalency Factors. The
following TEFs shall be used when
implementing human health or wildlife
criteria for 2,3,7,8-TGDD. The concentration
of each CDD and CDF in an effluent shall be
converted to a 2,3,7,8-TCDD equivalent
concentration by multiplying me ,
concentration of the CDD or CDF by the TEF
shown in Table VIIID.2 below, and
multiplying that product by the
bioaccumulation equivalency factor in Table
VHI.D.3 below. All resultant concentrations
shall be added to produce an equivalent
2,3,7,8-TCDD concentration. The equivalent
2,3,7,8-TCDD concentration shall be used to
establish TMDLs (including wastelqad and
load allocations) pursuant to procedure 3.
This equivalent 2,3,7,8-TCDD concentration
, shall also be used as the .concentration of "
2,3,7,8-TCDD for purposes of assessing the
total cancer risk of carcinogens pursuant to
section 4.D.
TABLE VIII.D-2.--TOXIC EQUIVALENCY
FACTOR VALUES FOR CDDs AND CDFs
TABLE Vlll.D-3.—BJOACCUMULATION
EQUIVALENCY FACTORS (BEFs)
" v Congener
2,3,7,8-TCDD :................
1 ,2,3,7,8-PeCDD ......:,..... ...
1 ,2,3,4,7,8-HxCDD
1 2,3,6,7,8-HxCDD .............;...
1 ,2,3,7,8,9-HxCDD :............
1 ,2,3,4,6,7,8-HpCDD
OCDD „
2,3,7,8-TCDF ........
1 ,2,3,7,8-PeCDF
2,3,4,7,8-PeCDF ...................
1 ,2,3,4,7,8-HxCDF „.. ....
1 ,2,3,6,7,8-HxCDF .....;...........
2,3,4,6,7,8-HxCDF
1 ,2,3,7,8,9-HxCDF ;
1 ,2,3,4,6,7,8-HpCDF
1 ,2,3,4,7,8,9-HpCDF
OCDF
TEF
1.0
.5 -
.1
.1
.1
.01
.001
.1
.05
.5
.1
.1
.1
.1
. .01
. .01
.001
Congener
2,3,7,8-TCDD .......„;
1,2,3,7,8-PeCDD .-.
1,2,3,4,7,8-rHxCDD
1,2,3,6,7,8-HxCDD
1 ,2,3,7,8,9-HxCDD
1 ,2,3,4,6,7,8-HpCDD ..*.
OCDD :
2,3,7,8-TCDF
1 ,2,3,7,8-PeCDF
2,3,4,7,8-PeCDF ...
1 ,2,3,4,7,8-HxCDF
1 ,2,3,6,7,8-HxCDF .....;'.......
2,3,4,6,7,8-HxCDF
1 ,2,3,7,8,9-HxCDF .....:...
1,2,3,4,6,7,8-HpCDF ...............
1 ,2,3,4,7,8,9-HpCDF
OCDF
TCDD
BEF
10
£0.8
£0.3
£0.2
£0.2
<0.03
£0.02
1.2
0.3
1.8
£03
£0.3
£0.5
£0.5
£0.003
£0.1
£0.005
Notes:
1..xBEFxTcPDBAF =
2. xBAF=lipid-based bioaccumulation factor
for total congener concentration in water.
The TEFs provided in Table Vm.D-2
are the same as those set forth in EPA's
1989 TEF Update. However, this Table
has been reorganized to make it
consistent With Table Vm.D-3 above
(which lists the BEFs for specific
congeners and does not include CDDs
and CDFs with TEF values of zero),
4, Request for Comment on Alternative
Approach
The text presented below represents
the proposal for additivity of the
Committees of .the Initiative, modified
by EPA to delete the application of TEFs
for PCBs to wildlife. EPA requests
comments on whether the language
below should be added to the
implementation procedures of the final
Guidance. , •
The toxic action of some pollutants in
mixtures is additive in their effects on
organisms. The following procedure
, establishes the manner hi which the additive
effects of chemical mixtures shall he treated. •
This provision shall be applied to point
source discharges.
A. Aquatic Life Effects. Whole-effluent
toxicity requirements established under
procedure 6 of appendix F of part 132 shall
be used to account for additive effects to
aquatic organisms. • ,
B. Wildlife Effects. When establishing
wasteload allocations (WLAs) for the
protection of wildlife, the effects of
individual pollutants shall he considered
additive for the pollutants for which toxicity
equivalency factors (TEFs), as provided in
section E of this procedure, are available. •
. C. Human Health—-Non-cancer Effects.
When establishing wasteload allocations
(WLAs) for the protection of human health
for non-carcinogens, the effects of individual
pollutants shall be considered additive for
the pollutants for which toxicity equivalency
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20944 Federal Re^ster 1 Vol. 58, No. 72 ? Friday, April 16, 1993 / Proposed Rules
factors, as provided hi part F of this
procedure, are available.
D. Human Health—Cancer Effects. When
establishing wasteload allocations (WLAs) for
tho protection of human health for
carcinogens, the following shall apply:
(1) Except as noted hi (2) below, in cases
where an effluent contains detected levels of
moro than one pollutant for which a Tier I
criterion or Tier n value exists and for which
a water quality-based limitation is required
under Procedure 5, the incremental risk of
•ach cardnogan shall be considered to be.
additive and the total cancer risk shall not
exceed 10~5. The wasteload allocation
(WLAJ for each carcinogen shall be
established in a permit to protect against
potential additive effects associated with
simultaneous, multiple-chemical human
exposure such that the following condition is
met:
rj C
.4. 2_+...+_±a—^1
WLA2 WLAn
Where:
Ci. . .n = tho monthly average effluent
limitation expressed as
concentration of each separate
carcinogen in the effluent.
WLAi. . ,n = the wasteload allocation
concentration calculated for each
substance at each permitted facility
independent of other carcinogens
that may be present in the receiving
waters based oa the human cancer
criterion for each respective
carcinogen.
(2) If tha permitting authority determines,
based on information submitted by the
p&rmiUea, that the carcinogenic risk for a
mixture is not additive, the permitting
authority may establish wasteload based on
that Information.
B. TEFs applied to Wildlife Effects. Tha
permitting authority shall usa toxlcity
equivalency factors when establishing
wasteload allocations for the protection of
wildlife for chlorinated dibonzodioxins
(CDDt) and chlorinated dibenzofurans
(CDFs). Tb* concentration of each CDD and
CDF in an effluent shall be converted to a
2,3,7,8-TCDD equivalent concentration by
multiplying the concentration of the CDD or
CDF by tha TEF shown In Table VHLD.4. All
resultant concentrations shall be added to
pro-due* an equivalent 2,3,7,8-TCDD
concentration. The equivalent 2,3,7,8-TCDD
concentration shall bo usod to establish a
wasteload allocation consistent with
procedure 3. Whenever one or more CDDs
and/or CDFs aro present in an effluent, the
permitting authority shall establish a
wasteload allocation for 2,3,7,8-TCDD. The
permittee shall be considered in compliance
only if thasum of the effluent concentration
times the TEF for all the CDDs and CDFs are
less or equal to the wasteload allocation for
2,3,7,8-TCDD. If there are carcinogens other
than CDDs and CDFs hi the effluent, the sum
calculated for tho equivalent 2,3,7,8-TCDD
concentration must bo used in the formula hi
D(l) abova foe Cj» where k represents 2,3,7,8-
TCDD.
F. TEFs applied to Human Health—Cancer
Effects. The permitting authority shall use
toxicity equivalency factors when
establishing wasteload allocations for human
health-based criteria for CDDs and CDFs. The
concentration of each CDD and CDF hi an
effluent shall be converted to a 2,3,7,8-TCDD
equivalent concentration by multiplying the
concentration of the CDD or CDF by the TEF
shown in Table VTH.D.4. All resultant
concentrations shall be added to produce an
equivalent 2,3,7,8-TCDD concentration. The
equivalent 2,3,7,8-TCDD concentration shall
be used to establish a wasteload allocation
consistent with procedure 3. Whenever one
or more CDDs and/or CDFs are present in an
effluent, the permitting authority shall
establish a wasteload allocation for 2,3,7,8-
TCDD. The permittee shall be considered in
compliance only if the sum of the effluent
concentration times the TEF fpr all the CDDs,
and CDFs are less or equal to the wasteload
allocation for 2,3,7,8-TCDD. If there are
carcinogens other than CDDs and CDFs in the
effluent, the sum calculated for the
equivalent 2,3,7,8-TCDD concentration must
be used hi the formula in D(l) above for Ck, •
where k represents 2,3,7,8-TCDD.
TABLE VlH-D-4.—Toxic EQUIVALENCY
FACTOR VALUES FOR CDDs AND CDFs
Compound
1. Dioxlns:
Mono-, Di-, and TriCODs ..
2,3,7,8-TCDD
Other TCODs
2,3,7,6,-PeCDO
Other PeCDDs
2,3,7.8-HxCDDs
Other HxCDDs
2,3,7,8-HpCDD
Other HpCDDs
OCDD'...™
2. Furans:
Mono-, Dl-, and TriCFDs ..
2,3,7,8-TCDF
Other TCDFs
2,3,4,7,8-PeCDF
1,2,3,7,8-PeCDF
Other PeCDFs.. ........
2,3,7,6-HxCDFs
Other HxCDFs
2,3,7,8-HpCDFs .„
Other HpCDFs
OCDF
TEF
value
0
1
0
0.5
.0
.1
.0
.01
.0
.001
0
0.1
.0
.5
.05
.0
.1
.0
.01
.0
.001"
5. Request for Comments
EPA requests comment on each
element of the text for the two
approaches to additivity presented in
sections 3 and 4 above, including all
subjects and issues raised in the
preamble discussion whether or not
specific regulatory text has been,
provided in the proposed Guidance, and
any suggested alternative requirements
or combinations of requirements to
address these elements and issues in the
final rule. EPA may promulgate final
rules based on any of the issues or
subjects discussed in this preamble or
based on a combination of possible
requirements to address these subjects
and issues.
E. Reasonable Potential for Exceeding
Numeric Water Quality Standards
The purpose'of this section is to
define the proposed procedures for
determining whether an NPDES permit
for discharges to the Great Lakes System
must include a water quality-based
effluent limitation for a parameter or
pollutant parameter (not including
whole effluent toxicity). Considerations
related to whole effluent toxicity and
the basis for such considerations are
addressed separately in section G of this
preamble. The proposed Guidance
would require permitting authorities to
follow specific procedures where
facility-specific effluent monitoring data
is available. Where this data is not
, available, including when all available
effluent data for a pollutant or pollutant
. parameter is below the applicable
analytical detection level, this Guidance
does not establish any new or specific
requirements, and permitting authorities
will continue to follow existing Federal,
, State or Tribal regulations and guidance.
Existing guidance for determination of
reasonable potential in the absence of
facility-specific effluent monitoring data
are discussed in section S.E.I of the
preamble, below.
1. Existing National Rules and Guidance
EPA's existing regulations require
NPDES permits to contain effluent
limitations necessary to meet applicable
technology-based requirements of
Federal and State law. These
technology-based limitations are
derived directly from application of
National effluent limitation guidelines
or on the basis of the permitting
authority's best professional judgment
(40 CFR 125.3); States are currently
required to adopt regulations consistent
with these provisions as part of their •
approved NPDES State permitting
program (40 CFR 123.25(a)(36)J, EPA is
not proposing to amend the
requirements governing the
establishment of technology-based
limitations in to the proposed Guidance.
In addition to these technology-based
requirements, EPA's existing regulations
require NPDES permits to include water
quality-based effluent limitations
(WQBELs) to control all pollutants or
pollutant parameters.which the . ..
permitting.authority determines are or
maybe discharged at a level which will
, cause, have the reasonable potential to
cause, or contribute to an excursion
above any water quality standard,
including numeric and narrative criteria
for water quality (40 CFR 122.44(d)(l))..
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Federal Register T Vol. 58, No; 72 7 FrUiayv
16,' 1993 / Proposed Rules
20945
When determining whether a discharge
will cause, has the reasonable potential
to cause, or contributes to an excursion
above any State or Tribal water quality
standard, the permitting authority must
use all relevant available data, including
facility-specific effluentmonitoring data
where available. Additionally, the ,
permitting authority must use
procedures which account for existing
controls on point and nonppint sources
of pollution; variability of the pollutant
or pollutant parameter in the effluent;
and, where appropriate, the dilution of
the effluent in the receiving water (40
. CFR 122 44(d)(l)(ii)). If the permitting-
authority determines that a discharge .
has the reasonable potential to cause or
contribute to an excursion of an
applicable numeric or narrative water
quality criterion, it must include a
WQBEL for the individual pollutant in
the permit (40 CFR 122.44(d)(l)(iii)). In
the absence of a numeric water quality
criterion for an individual pollutant
under these circumstances, the' •
permitting authority must derive
appropriate WQBELs from thq State or
Tribal narrative water quality criterion
by: using a calculated numeric criterion
for the pollutant that attains the
applicable narrative criterion and
protects designated uses; establishing
effluent limitations on a case-by-case '
basis using EPA's water quality criteria
developed under section 304(a) of the
; Clean Water Act, supplemented with
other information where necessary; or
establishing effluent limitations on an
indicator pollutant (40 CFR
EPA has provided guidance on how to
apply these requirements in the
"Technical Support Documenifor Water
Quality-based Toxics Control (TSD)"
(EPA/505/2-90-081,. March 1991),
which is available in the administrative
record for this rulemaking. Copies are
also available upon written request from
the person listed in section XIII of this
preamble. In the TSD, EPA recommends
that facility-specific effluent monitoring
data be used, where available, to project
receiving water concentrations, which
are then compared to water quality
criteria. This comparison in the TSD
guidance is comprised first of
calculating the pollutant concentration
in the receiving water after considering
dilution (if allowed by the water quality
standards regulation), the contributions
.of other point and nonpoint sources,
and the potential for effluent variability
,to justifyhigher effluent concentrations:
. than have actually been measured; and
second, comparing this calculation to
the applicable water quality criterion.
The TSD guidance allows the permitting
authority the flexibility to determine the
appropriate approach for assessing
reasonable potential. For example, an.
authority may opt to use a stochastic ,
dilution model that incorporates both
ambient dilution and effluent variability
rather than use a steady state dilution ;
model with a statistically defined
maximum effluent concentration. Also,
a permitting authority may develop a
WQBEL in lite absence of facility-
specific effluent monitoring data. .
Whatever approach is selected by the
authority, it must satisfy all .
requirements of 40 CFR 122.44(d)(l)(ii)
summarized above.
One of four outcomes will be reached
when using the TSD protocol:
a. Excursion Above the Water Qualify
Standard. If the permitting authority .
determines that pollutants or pollutant
parameters in a facility's discharge are
or may be discharged at a level which
causes or contributes to an excursion
above a narrative or numeric water
quality criterion, it must establish a
WQBEL m the permit for those
pollutants (40 CFR 122.44(d)(l)(i).
b. Reasonable'Potential for Excursion
Above the Water Quality Standard, If
the permitting authority determines that
pollutants or pollutant parameters in a
facility's discharge are or may be
discharged at a level which has the
reasonable potential to cause or '. - .
contribute to an excursion above a
narrative or numeric water quality
criterion, it must establish a WQBEL in
the permit for that pollutant (40 CFR :
122.44(d)(l)(i)J. EPA believes that
reasonable potential is shown where an
effluent in conjunction with other
sources of a pollutant is projected to
cause an excursion above the water
quality criterion. This projection is
based upon an analysis of available data
that accounts, for limited sample size
and effluent variability. EPA's guidance
in the TSD does not, however, constrain -
the determination of reasonable
potential to a projection of an excursion
above a water quality criterion based
solely on effluent variability. The . ,
. guidance recognizes that reasonable
potential determinations include
consideration of the factors in 40 CFR
122.44(d)(l)(iij and any other
appropriate factors based on the
professional judgement of the
permitting authority. These other factors
; may include the existing data on toxic .
pollutants; type of receiving water and
. designated uses (e.g., high-use fishery);
relative proximity to the-water quality
standard; existing controls on point and
nonpoint sources; compliance history of
the facility; and type of treatment
facility. ,: ,
c. No Reasonable Potential for
Excursions Above the Water Quality
Standards. If the permitting authority
determines that the pollutants or
pollutant parameters in a facility's
discharge are not discharged at a level
that have the reasonable potential to
cause or contribute to an excursion
above a narrative or numeric water
quality criterion, then a WQBEL for
those pollutants is not necessary. In
these situations, EPA's guidance
recommends that the effluent.
monitoring be repeated at a frequency of
at least once every five years (see TSD
at p. 64).
d.Inadequate Information. If a
permitting authority has inadequate
information to determine whether a
discharge contains pollutants or
pollutant parameters which are or may
be discharged at a level which has the
reasonable potential to cause or '
contribute to an excursion of a narrative
or numeric water quality criterion, ..
EPA's existing guidance recommends
that the permit contain appropriate
monitoring requirements and a reopener-
clause (see TSD at p. 64). This clause
would require reopening of the permit
and establishment" of a WQBEL based
upon any monitoring results or other
new factors which substantiate that the
effluent causes, has the reasonable
potential to cause, or contributes to an
excursion above water quality ..:.
standards.
2. Proposed Procedure 5
Procedure. 5 of the proposed Guidance
requires jthe permitting authority to
include a WQBEL in an NPDES permit
whenever a pollutant is or may be r
discharged into the Great Lakes System
at a level which will cause, have the •
reasonable potential to cause, or •
contribute to an excursion above any •
Tier I criterion or-Tier H value. .
Procedure 5 of appendixF to part 132
sets forth a two-step process for
.determining whether the discharge of a
pollutant will cause, have the -
reasonable potential to cause, or
contribute to an excursion above any
Tier I criterion or Tier II value. -."-..-.
First, under procedure 5.A of :
appendix F, permitting authorities must
develop preliminary effluent limitations
that will ensure that all Tier I criteria
and Tier n values will be met in-stream, ••
after discharge where there is sufficient
data to develop such criteria or values.
If such data do hot exist, permitting
authorities must apply the provisions in.
procedure 5.D of appendix F to
determine whether such data must be
generated. Second, procedure 5..B and
5.C of appendix F set forth procedures ;
to be followed to determine: the, •...'...- .
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20946 Federal Register / Vol. 58, No. 72 I Friday, April 16, 1993 / Proposed Rules
projected effluent quality (PEQ) of the
effluent that will be discharged; and
whether a WQBEL must be established
based on specified ratios between the
PEQ and the preliminary effluent
limitation. If such effluent data do not
exist or if all such effluent data for a
pollutant or pollutant parameter are
below the analytical detection level for
that pollutant or pollutant parameter,
permitting authorities will continue to
apply existing Federal, State or Tribal
regulations and guidance for making
reasonable potential determinations.
Finally, procedure 5.E of appendix F
provides that, regardless of the manner
in which the reasonable potential
determination is made, all effluent
limitations must also comply with all
other applicable State, Tribal and
Federal requirements.
The proposed Guidance provides
permitting authorities with specific
requirements for making reasonable
potential determinations based on
faeilUy-spacific effluent monitoring data
consistent with the provisions of 40 CFR
122.44(dKlXO. (ii), (Hi), and (vi). As
discussed in section n.D of the
preamble, the proposed Guidance
requires the States and Tribes to adopt
the Tier I criteria in Tables 1 through 4
of 40 CFR part 132 and the
methodologies for deriving Tier I
criteria and Tier n values in appendixes
A, C, and D of 40 CFR part 132 into their
water quality standards for the Great
Lakas System. Part 132.3 of the
proposed Guidance defines Tier I
criteria as:
* * * numeric values derived by use of the
Tier I methodologies in appendixes A, C and
D, Uia methodology in appendix B, and the
procedures in appendix F, that either have
MO a adopted as numeric criteria into a water
qutlity standard or aro used to implement
narrativo water quality criteria.
Tier n values are defined as:
• * * numeric values derived by use of the
Tier II methodologies in appendixes A, C and
D, tho methodology in appendix B, and the
procedures in appendix F, that are used to
Implement narrativo water quality criteria.
Procedure 5 implements the provisions
of 40 CFR 122.44(d)(l)(i) for discharges
%vithin the Groat Lakes System by
requiring that WQBELs be established
whenever pollutants or pollutant
parameters "are or may be discharged at
a level which will cause, have the
reasonable potential to cause, or
contribute to an excursion above any
State water quality standard, including
State narrative criteria for water
quality." Procedure 5 of appendix F is
also consistent with the provisions of 40
CFR 122.44(dKD(iiilrequiring WQBELS
bo established whenever a discharge
"causes, has the reasonable potential to
cause, or contributes to an in-stream
excursion above the allowable ambient
concentration of a State numeric
criterion" because the Tier I criteria will
serve as minimum numeric water
quality criteria for the Great Lakes
System.
Procedure 5 of appendix F to part 132
is also consistent with the provisions of ,
40 CFR 122.44(d)(l)(vi)(A). This section
requires authorities to establish
WQBELS to implement narrative water
quality criteria using one or more of the
specified options. Option
122.44(d)(l)(A) allows the permitting
authority to establish WQBELs using a
calculated numeric water quality
criterion for the pollutant that will
attain and maintain applicable narrative
criteria and fully protect the designated
uses. The Guidance implements this
option by providing Tier I and Tier n
methodologies to translate narrative
water quality criteria into numerical
criteria or effluent limitations.
Finally, procedure 5 of appendix F to
part 132 also includes consideration of
controls on point and nonpoint sources
and dilution (see procedure 5. A of
appendix F) and effluent variability
through statistical characterizations (see
procedures 5.B and 5.C of appendix F),
'and is, therefore, consistent with the
requirements of 40 CFR 122.44(d)(l)(ii).
The procedures of this section are not
intended to implement the regulations
at 40 CFR 122.44(d)(l) (iv) and (v)
which pertain to whole effluent toxicity.
These provisions are implemented by
procedure 6 of appendix F of the
proposed Guidance. Furthermore, the
procedures of this section do not affect
the permitting authorities' existing
obligation to implement the regulations
at 40 CFR 122.44(d)(l)(vii) which
pertain to expression of WQBELs.
a. Developing Preliminary Effluent
Limitations. Procedure 5.A of the
proposed Guidance describes how the
permitting authority must establish
preliminary effluent limitations. For a
specific water body or stream segment,
the allowable total maximum daily load
(TMDL) for a pollutant is defined as the
sum of the individual wasteload
allocations (WLAs) and load allocations
(LAs); a margin of safety is included to
ensure that allocated loads, regardless of
source, will not produce an excursion
above water quality standards. The
WLAs are those portions of the TMDL
assigned to point sources; the LAs are
those portions of the TMDL assigned to
nonpoint sources and background
sources. (40 CFR 130.2(f)). Iii procedure
5. A of appendix F of the proposed
Guidance, the permitting authority is
required to develop preliminary
wasteload allocations based upon and
consistent with the wasteload allocation
procedures defined in procedure 3 of
appendix F of the proposed Guidance,
and then develop preliminary effluent
limitations based on the preliminary
wasteload allocations.
Procedure 5.A.2 of appendix F of the
proposed Guidance specifies the
procedure for developing preliminary
effluent limitations based on the
preliminary wasteload allocations. The
preliminary effluent limitations are
expressed as either a single day value,
a weekly average, or a monthly average,
and are used in determining if a facility
causes, has the reasonable potential to
cause or contribute to excursions above
water quality criteria by being compared
to actual effluent information in
procedure 5.B of appendix F. Because
the preliminary effluent limitations are
for use to compare to actual effluent
information, the Guidance expresses the
preliminary effluent limitations in the
same form that effluent data are
.typically available to permitting
authorities. Effluent information is
typically available to jpermitting
authorities either in the permit,
application or in the Discharge
Monitoring Records (DMR). Both the
application for.rns and DMRs require
effluent concentrations to be reported as
weekly and monthly averages for
publicly owned treatment works
(POTWs) and as single day values and
monthly averages for non-POTW. The
use of these single day values, weekly
averages, and monthly averages allows
for direct comparison of preliminary
effluent limitations to effluent data
without requiring additional
manipulations or conversion of the
effluent data. EPA believes that this
reduces the burden to the permitting
authorities and facilities in reviewing
and using effluent concentration data in
determining if a WQBEL is necessary.
Each preliminary wasteload allocation
has a corresponding preliminary
effluent limitation which matches to the
extent possible the criterion (or value)
and dilution basis used to develop the
wasteload allocation. The preliminary
effluent limitation based on wildlife
criteria is expressed in proposed section
5.A.2 as a monthly average because the
wasteload allocation is calculated usiiig
a 30-day (monthly) average flow under
proposed procedure 3 of appendix F.
The preliminary effluent limitation
based on human health criteria is
expressed as a monthly average because,
although the wasteload allocation is
calculated using a harmonic mean
(annual) river flow, the monthly
averaging period is the closest
expression of the preliminary effluent
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Federal, Register / Vol. 58, No. 72 /Friday,^ April 16, 1993 / Proposed Rules
20947
limitations to an annual average. The ,
preliminary effluent limitation eased on
acute aquatic life .criteria is expressed as
a daily value to reflect that the criteria
themselves are expressed as: one-hour ;
: averages and the wasteload allocation is
calculated using a seven-day (weekly)
average 'river flow. The preliminary .
effluent limitation based on chronic
aquatic life criteria is expressed as a
weekly average value to reflect that the
criteria themselves are expressed as
four-day averages and the wasteload;
allocation is calculated using a seven- -
day (weekly) average river flow. In :
addition, the preliminary'effluent
limitation based on chronic aquatic life
criteria can as an option be expressed as
a monthly average value to reflect that
weekly average effluent data; may not be
available for non-POTW facilities.
Because the preliminary effluent
limitations are based on the preliminary
wasteload allocations; procedure S.A.I
of appendix F accounts for dilution and
existing controls on point and.nonpoint
sources of pollution, two of the required
factors of federal NPDES regulations at
40 CFR 12'2.44(d)(l}(ii). The remaining
factor of 40 CFR 122.44(d)(l)(iij, the
potential for effluent variability, is
accounted for in procedures 5.B and S.C
of appendix F of the proposed
. Guidance. r
: The proposed procedures in
procedure 5. A of appendix F are limited
to determination of the need for a
WQBEL. Procedures for converting
wasteload allocations into WQBELs and
for expressing effluent limitations in .
NPDES permits shall continue to be
governed by existing State, Tribal and
Federal requirements or guidance (see
40 CFR 122 45(d) and (e)).
EPA invites comment on all aspects of
the proposed methodology for .•
calculating a preliminary effluent
limitation, including the
appropriateness of specifying a
methodology and any suggested
alternative methodologies. In particular,
EPA invites comment on whether.the
preliminary effluent limitation needs to
be expressed using exactly the same ;
terms as the wasteload allocation (e.g.,
an annual average preliminary effluent
limitation based on a wasteload
allocation for human health protection),
EPA also invites specific comment on
the use of probabilistic or dynamic
modeling procedures to calculate the
preliminary wasteload allocations
instead of the procedures proposed in
procedure 3 of appendix F.
•b. Determining yVhether There is
Reasonable Potential to Exceed the
Preliminary Effluent Limitations.
Procedures 5.B and 5.C of appendix F of.
the proposed Guidance specify.
procedures for determining the .,
Projected Effluent Quality (PEQ) based
on fadlity-specific-effluent monitoring
data. Available effluent monitoring data
. includes information from discharge
monitoring reports (DMRs), data from
NPDES permit application forms 2A and
2C, and other data requested of or
submitted by the facility of'available to
the permitting authority. Procedures 5.B
and S.C of appendix F specify -
procedures for determining the PEQin .
three different situations: procedure, ;.'.
5.B.1 of appendix F addresses situations
where ten or more effluent data points
are available and the effluent flow rate
is less than the seven-day, 10-year low
flow rate of the stream, or the discharge
is to the' Open Waters of the Great Lakes;
procedure 5.B.2 of appendix F addresses
•situations where tea or more effluent ;
data points are available and the
effluent flow rate is equal to or greater
than the seven-day; 10-year, low flow of,
the stream; and procedure 5 C of,
appendix F addresses situations wherei
at least one but less than ten data points
exist, regardless of the effluent flow rate.
i. Determining Reasonable Potential' ,
Where Ten or More Effluent Data Points
are Available and the Effluent Flow Rate
is Less than the 7-day, W-yearFlow
Rate or the Discharge is to Open Wafers
of the Great Lakes. Procedure S.B.I of ;
appendix F to part 132 provides two
alternative methods of developing the
PEQ for discharges to the open waters
of the Great Lakes or to free flowing.
streams where the effluent flow rate is ..'
less than the stream seven-day, 10-year
flow. The first method, which is set
forth at procedures S.B.I.a through c of
appendix F, requires the PEQ to be
specified as: Thp greater of the
maximum daily effluent concentration
or the' 89th percentile of the distribution
of the daily data; the 99th percentile of
the; distribution of mbnthly averages;
and the 99th percentile of the
distribution of weekly averages. Under,
this first method, a WQBEL must be ,
established if the maximum effluent
concentration or the 99th percentile,of
the available daily data .exceeds the,
preliminary effluent limitation based on;
the criteria and values for the protection
of aquatic life from acute effects; the
99th percent^ of the distribution of
monthly averages exceeds the ^
preliminary effluent limitation based on
' criteria and values to protect aquatic life
from chronic effects, human health or
wildlife; or the 99th percentile of the .
distribution of weekly averages exceeds
the prelimuiary effluent limitation T
based on the criteria and values for
protection of aquatic life from chronic
effects.
The basis for the first approach is that
reasonable potential decisions must be
performed ;forthose effluent and ,
environmental conditions which cause,
have the reasonable potential to cause or
contribute to an excursion above a water
quality criterion. The consideration of
: effluent variability is an important .
component of the reasonable potential •
decision. Accordingly, the Great Lakes
Initiative Steering Committee developed.
procedure 5;B.l.a through S.B.l.c of
appendix F to provide a statistical ;
approach to better characterize the " '
effects of effluent'Variability as
measured by a predicted maximum
effluent concentration. In the proposed
rule, the estimated maximum
concentration is calculated, in most .
applications, as an upper bound (99th
percentile) of the distribution of effluent
concentrations. The 99th percentile was
selected as a reasonable measure of the
maximum effluent concentration. Where
a sufficient number of effluent .
measurements exist, the maximum .
value of all of the concentrations may be
a close approximation of the 99th
percentile concentration! The
. information is then used by the ,
permitting authority to determine the
need for a WQBEL. '-' ' • .
The second method, which is set forth
at procedure S.B.l.d'of appendix F to
part 132, provides that the PEQ may be
calculated as the upper 95 percent
confidence level of the 95t£ percentile
based on a log-normal distribution of '
the effluent concentration data. This
statistical procedure is consistent with
the procedure described in section 3.3
of the TSD. Procedure S-.B.l.d of •'.
appendix F specifies that a WQBEL
must be established if the PEQ, as
calculated under this second method," ,
exceeds any/of the preliminary effluent •''•'
limitations developed in accordance
with section 8.A. ' ,
The basis for procedure: S.B.l.d of
appendix F to part 132 is that all
effluent assessment approaches for
individual pollutants have some degree
of uncertainty associated with them. .
; The more limited the amount of test
• data available, the larger the uncertainty
• and the lower the precision of the
methodology for characterizing the
maximum effluent concentration.
Because of this uncertainty, EPA
. developed the guidance in the TSD to
provide a statistical approach to better
characterize the effects of effluent
; variability and reduce uncertainty in the
process of deciding whether to require
a WQBEL for a particular pollutant. The.
TSD guidance combines knowledge of
effluent variability as estimated by a
coefficient of variation with the * ..
, uncertainty due to a limited number of.
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20948
Federal Register / Vol. 58. No. 72 /Friday, April 16, 1993 /Proposed Rules
data to project an estimated maximum
concentration for individual pollutants
In a facility's effluent. The estimated
maximum concentration is calculated as
an upper bound of the expected
lognormal distribution of effluent
concentrations at a high confidence
level, Tn0 information is then used by
tha permitting authority to determine
the need for a WQBEL.
Procedure S.B.l.d of appendix F to
pert 132 is based on the principles
expressed in the TSD guidance
document. Under procedure S.B.l.d of
appendix F to part 132, the PEQ is
calculated by multiplying the maximum
effluent concentration value by a factor
which represents the uncertainty in the
dcgroo of variability in the effluent. The
specific value of this factor depends
upon the number of effluent
concentration values and the variability
of the effluent. The proposed Great
Lakes Guidance provides these factors
to Table 1 of procedure 6 of appendix
F.
Tho calculation of the factors in Table
8 of procedure 6 of appendix F to part
132 has two parts. The first is
characterization of the highest measured
effluent concentration based on the
desired confidence level. The
relationship that describes this is:
pn S: (1 - confidence level)1/n
%vhera "pn" is the lower bound ("worst
case") percontile represented by the
highest concentration in the data and
"n" is the number of samples.
The second part of this calculation is
a relationship between the percentile
described above and the selected upper
bound of the lognormal effluent
distribution. EPA's industrial treatment
effluent database, which was used by
EPA to develop and promulgate effluent
guidelines, suggests that the lognormal
distribution characterizes effluent
concentrations well. For example, if five
samples were collected (of which the
highest value represents at least the 40th
percentile at the upper 95 percent
confidence level), the coefficient of
variation is 0.6, and the desired upper
bound of the effluent distribution is the
95th percentils, then the two percentiles
can bo related using the coefficient of
variation (CV) as shown below:
C9S = exp(l.645(T-0.5a*) =^
c4Q exp(-0.258
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Federal Register / Vol. 58, No. 72 /.Friday, April 16, 1993 / Proposed Rules 20949
year FlowRate.. Procedure 5.B.2 of •
appendix F the proposed Guidance
establishes requirements .for situations
where the effluent flow rate is equal to
or greater than the critical low flow of
the stream (7Q10) and 1Q or more
effluent data points are available. In
such effluent dominated discharge
situations, the requirements are
identical to those in procedure 5.B.1 of
appendix F with two exceptions: The
maximum effluent value, the 99th
percentile value of daily samples and
the 99th percentile value weekly and
monthly averages must be compared to
50 percent of the preliminary effluent.
limitations based on wasteload
• allocations (instead of to the full 100
percent of the preliminary limitations);
and use of the statistical approach ':
contained in procedure S.B.l.d of
appendix F is precluded. Open Waters
of the Great Lakes System are not
considered to be effluent dominated
under any circumstance because the-
volume of surface water is much greater
than the volume of effluent; '
, With respect to the first difference,
the proposed requirement to compare
the PEQto 50 percent'of the preliminary
effluent limitation will not increase the
stringency of a WQBEL; instead it better
ensures that a WQBEL will be included
in a NPDES permit in effluent
dominated, situations in the Great Lakes
System due to the lack of ambient
dilution to compensate for the effects of
high effluent concentrations. Because
the procedures in procedure 5.B of
appendix F are based on statistical
estimates, there is a smalTpotential for
a facility to discharge pollutants at
higher concentrations that would
exceed a water quality criterion. One
fundamental principle of the statistical
methods used in procedure 5.B of
appendix F is that a*higher
concentration is always possible
although less likely to occur. This
potential is offset by consideration -of
the available dilution in the receiving -
water, because the simultaneous , ;
occurrence of the high effluent
concentration and low stream flow is
rare. In contrast, there is little
' substantial ambient stream flow in
streams with low dilution capacity. EPA
believes that the 50 percent factor in
procedure 5.B of appendix F provides a
reasonable level of assurance that a
WQBEL is imposed where appropriate.
With respect to the second difference,
the statistical approach described in -
procedure S.B.l.d of appendix F to part
132 does not provide a separate explicit
mechanism to account for the need for
additional assurances in low dilution
streams. Rather, the approach addresses
this factor implicitly in tJfre selection of "
the confidence level used. In instances
of low dilution streams, a permitting
authority could use a higher confidence
levelto increase the likelihood that a
WQBEL will be required and thereby
provide the appropriate level of
additional assurance. EPA believes that
proper application of the proposed
procedures under procedures S.B.l.d
and 5.B.2 of appendix F may result in
the same likelihood of requiring a •
WQBEL. EPA is not proposing to allow
use of procedure S.B.l.d of appendix F
in effluent dominated streams, however,
because the TSD does not include
specific guidance on how high to adjust
the confidence level in these situations,
EPA invites comment on whether the
level of at least 50 percent of the
potential limitation in a effluent
dominated situation is reasonable to
ensure that WQBELs are required where
necessary, and whether the statistical
approach in procedure 5.B.l,d of '
appendix F or an alternative approach
based on the TSD should also be
available as an option to the permitting -
authority, -
iii. Determining Reasonable Potential
Where there is at Least One but Less
than Ten Data Points Available.
Procedure 5,C of appendix F to the
proposed Guidance establishes
requirements for determining reasonable
potential for small data sets (those with
.at least one, but less than 10 samples).
The approach in procedure 5.C of-
appendix F is consistent with procedure
5.B.l.d of appendix F discussed above
and is also consistent with the
recommendations in Chapter 3 of the
TSD. Under this provision, a maximum
value is calculated from the highest
value in the data set and a multiplying
factor is based pn the assumption that
the coefficient of variation is 0.6 for all
effluents, EPA believes that where there
are less than 10 items of data, the
uncertainty in the coefficient of
variation is .too large to calculate a
standard deviation or mean with
sufficient confidence. Based on the data
in EPA's effluent guidelines database,
which was used to develop and
promulgate effluent guidelines for
industrial wastewaters, a coefficient of
variation of 0.6 typifies average effluent
variability. For this reason, only one
value of the coefficient of variation is
assumed. If the maximum value thus
calculated is greater than the ';
preliminary effluent limitations based
on the preliminary wasteload
allocations, a WQBEL must be included
in the permit,
EPA invites comment on all aspects of
this provision, including whether a
distinction should be made basedjan'the
number of representative effluentHata
samples, and whether 10 or less such
samples is an appropriate basis for
making a distinction. EPA also requests
comment on establishing a coefficient of
variation of 0.6 when there are fewer
than 10 representative effluent data
samples.
c. Determining the Need for Water !
Quality-based Effluent Limitations in
the Absence of Effluent Monitoring Data
fora Specific Facility. The proposed
Guidance does not establish any new or
specific requirements for determining
the need for WQBELs in the absence of
effluent data for a specific facility. In
these instances, the permitting authority
must continue to apply, existing : *
regulations and procedures consistent
with 40 CFR 122.44(d)(l) to determine
on a case-by-case basis whether
WQBELs are necessary. EPA's existing
guidance recommends that the
regulatory authority use a variety of :
. factors and information when
determining whether or not a discharge
will cause, has the reasonable potential
to cause, or Contributes to an excursion
of a" water quality standard if facility-
•specific effluent monitoring data are
unavailable. (See TSD at pp. 50-55.) At
a minimum, the proposed Guidance,
consistent with existing regulations,
requires the permitting authority to
consider the four factors identified in 40
CFR 122.44(d)(l)(ii) in making a
reasonable potential determination
regardless of the availability of facility-
-specific effluent monitoring data.
If the permitting authority, after
evaluating all available information on
the facility, is not able to determine
whether the discharge will cause, has ','.
the reasonable potential to cause, or
contributes to an excursion above a
water quality standard, existing EPA
guidance provides that the authority
should require whole effluent toxicity or
chemical-specific effluent monitoring to
acquire additional data. The permitting
authority should require the monitoring
prior to permit issuance, if sufficient
time exists, or as a condition of the
issued or reissued permit. If monitoring;
is required after permit issuance, the
permitting authority should also include
, a specific reopener clause to allow for
subsequent modification of the permit .
to include a WQBEL if the monitoring
establishes that the discharge causes,
has the reasonable potential to cause, or
contributes to an excursion above a • -
water quality .criterion. (See TSD at p.
55) - .. ,. . -.'•••'. - -.'-./.- ..-.--
EPA invites comments on whether
existing guidance is sufficient for •'
determining the need for WQBELs in ^
the absence of facility-specific effluent
monitoring data, or whether minimum
requirements should be specified iivthe
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20950
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
final Guidance. EPA also solicits
comments on any alternative procedures
to make this determination in the
absence of facility-specific data.
d. Determination of Reasonable
Potential for Pollutants for Which Great
Lakss Tier It Values are Not Available.
Procedure 5,D of appendix F of the
proposed Guidance specifies
requirements for determining whether
pcrmitting-authoritios must generate or
require permittees to generate, data
sufficient to calculate Tier H values
when pollutants on Table 6 are known
or suspected of being discharged into
Lho Great Lakes System, but neither Tier
I criteria nor Tier n values have been
derived duo to a lack of toxicological
data. In some cases, toxicological data
for a particular pollutant may be
available which meets the minimum
database requirements for one of the
categories of Tier I criteria or Tier n
values, for example aquatic life, but not
for human health and wildlife. Other
cases may involve a pollutant present in
the effluent for which, no toxicological
data exist. A preliminary assessment
conducted by EPA indicates that there
are data currently available to calculate
Tier I or Tier E criteria/values for
aquatic life, human health and wildlife
for most of the pollutants in Table 6.
EPA recognizes that it would be
preferable to have Tier I criteria
available to compute WQ3ELs in all
circumstances. However, the
development of Tier I criteria is often
costly and time-consuming. In the
absence of a Tier I criterion, the
permitting authority must have some
mechanism with which to interpret and
ensure that the narrative prohibition
against tho discharge of toxic substances
in toxic amounts is reflected in permits
(40 CFR 122.44(dKD(vi)).
Tha Steering Committee considered
four options to address the discharge of
pollutants in the absence of Tier I
criterion: preclude discharge of the
pollutant unless and until a Tier I
criterion is developed; allow
unregulated discharge unless and until
a Tier I criterion is developed; allow
permitting authorities to translate the
narrative criterion into a numeric
criterion on a case-by-case basis; or
develop systematic methodologies for
deriving numeric criteria and
determining the need for a WQBEL to
implement the criteria in the absence of
a full database. As discussed in section
II.D of the preamble above, the proposed
Guidance implements the latter
option—to propose the use of a Tier II
methodology to derive values in the
absence of Tier I criteria. Consistent
with this decision, procedure 5.D of
appendix F proposes a methodology for
determining whether Tier n data must
be generated by the permitting authority
or discharging facility to determine the
need for a WQBEL for a pollutant in the
NPDES permit.
Procedure S.D.I of appendix F the
proposed Guidance requires the
permitting authority to use all available,
relevant information including
Quantitative Structure Activity
Relationship (QSAR) information and
other relevant toxicity information to
develop "ambient screening values" for
each of the following water quality
criteria categories: aquatic life (acute
and chronic); wildlife; and non-cancer
human health for pollutants included iri
Table 6 of the proposed Guidance.
These ambient screening values must be
specified at a level which would not be
expected to cause an excursion of the
narrative water quality standard.
Examples on development of ambient
screening values are provided in
"Technical Support Document:
Establishment of Ambient Screening
Values under the Great Lakes Water
Quality Initiative", February 1993,
which is available in the administrative
record for this rulemaking. Copies are
also available upon' written request from
the person listed in.section XIII of this
preamble.
Based on the specifics of the effluent
data base and discharge situation (i.e.,
whether there are more or less than 10
data points for the particular pollutant
in the effluent, and whether it is an
effluent dominated or a non-effluent
dominated receiving water), the
permitting authority must apply the
appropriate procedure described in
procedures 5.A, 5.B or 5.C of appendix
F to calculate a preliminary wasteload
allocation and preliminary effluent
limitation using the calculated ambient
screening value. If based on this
information, the permitting authority
concludes the discharge will cause, has
the reasonable potential to cause, or
contributes to an excursion above
ambient screening value, the regulatory
authority must either generate or require
the permittee to generate the data
necessary to derive Tier n values for the
protection of aquatic life, wildlife, and
human health for the pollutant. Once
sufficient data are generated to calculate
a Tier n value, the permitting authority
must follow the procedures set forth in
procedures 5.A through 5.C of appendix
F to determine whether a WQBEL must
be incorporated into an NPDES permit
based on the Tier n value.
Procedure 5.D.2 of appendix F of the
proposed Guidance includes an
alternative provision for existing
discharges of pollutants listed in Table
6 other than those identified as
bioaccumulative pollutants of concern,
if data sufficient to calculate Tier I .
criteria and Tier H values for aquatic life
are not available. In these cases,
proposed procedure 5.D.2 of appendix F
does not require permitting authorities
to generate or have the permittee
generate the data necessary to derive
Tier n values for aquatic life or include
pollutant-specific, aquatic life-based
effluent limits in the NPDES permit for
the discharge of those pollutants if the
discharge is to segments where a
biological assessment has demonstrated
no acute or chronic effects on aquatic
organisms and the whole effluent has
not exhibited toxicity in accordance
with the procedures in procedure 6 of
appendix F. Procedure 5.D.2 of
appendix F allows this exception from
the procedures in proposed procedure
S.D.I of appendix F for non- • •,
bioaccumulative chemicals of concern
as defined in proposed 40 CFR 132,2.
EPA is proposing procedures 5.D.1
and 5.D.2 of appendix F to implement
the existing NPDES regulation at 40 CFR
122.44(d)(l)(vi). These regulations
direct permitting authorities in the
absence of an applicable numeric water
quality criterion, to establish effluent
limitations for pollutants that cause,
have the reasonable potential to cause,
or contribute to an excursion of a
narrative water quality criterion using
one or more of the following options:
calculate a site-specific numeric
criterion; use EPA's water quality
criteria (developed in accordance with
section 304(af6f the Clean Water Act)
supplemented where necessary by other
relevant information; or establish
effluent limitations on an indicator
pollutant. Proposed procedure 5.D.1 of
appendix F implements the first option
by providing a mechanism to determine
whether the effluent has the reasonable
potential to cause or contribute to an
exceedance of the Tier H values. As
discussed in section n.D above, these
values will serve as calculated
minimum water quality criteria for an,
individual discharge to the Great Lakes
System. The Steering Committee
believed that a prescribed methodology
for conducting reasonable-potential
determinations was necessary to
improve consistent translation of
narrative water quality criteria within
the Great Lakes System. The proposed
approach is also consistent with existing
regulations which allow permitting
.authorities to require permittees to
submit any data necessary to support
permit development. If the permitting
agency determines that a pollutant is or
may be discharged at a level that will
cause, have the reasonable potential to
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Federal, Register /Vol. 58, No. 72 /Friday, April 16, 1993 /Proposed Rules 20951
cause, or contribute to an exceedance of
any water quality standard including
narrative criteria, it may require the ,
submittal of data necessary to compute
a WQBEL for that pollutant, including ,
the data necessary to calculate a Tier I
' value. EPA invites comment on all
aspects of this provision including
whether permitting authorities should
be allowed to use alternative procedures
consistent, with 40 CFR 122.44(d)(l)(vi)
"in interpreting a State's narrative water
quality criterion for the purposes of
establishing a WQBEL. , ":
The proposed .Guidance in procedure
5.D.1 of appendix F to part 132 does not
require the permitting authority to
estimate ambient screening values or to
generate or require the generation of
data sufficient to develop a Tier II value
for human health based on carcinogenic
effects; For such pollutants,, the Steering
Committee believed that permitting ..
, authorities already have sufficient
information to protect human health
from, carcinogenic effects by applying
one of the three options specified in 40
CFR 122.44(d)(l)(vi) for the purpose of
determining whether a discharge has the
reasonable potential to cause or
contribute to an exceedance of a,
narrative water quality criterion for
human health based on carcinogenic
effects. In contrast to wildlife, aquatic
•life, and non-carcinogenic criteria, EPA
has developed criteria pursuant to
section 304(a) of the CWA or maintains
information for developing a criterion to
.protecting human health from ,
carcinogenic effects for all but four, of.
the "pollutants listed hi Table 6: 2-
chloroethyl vinyl ether, 2-chlorophenyl
phenyl ether, di-n-octyl phthalate, and
octaehlorostyrene.. EPA currently does
not have information to indicate
whether these pollutants have the
characteristics of carcinogens, and
invites comment oh this.
Permitting authorities must consider
all relevant information, including
criteria published by EPA pursuant to
304(a), in making reasonable potential
determinations under 40 CFR
122-.44(d)(l)(vi). EPA believes that the .
above approach of using 304(a) criteria
, and other information available, to
calculate a criterion satisfies the
' requirements of § 122.44(d)(i)(vi) while.
providing flexibility to the permitting'
authority to establish any necessary :
effluent limitations to meet narrative or
numeric .water quality criteria and fully
protect designated'uses. EPA invites
comment on all aspects of this provision
including whether the permitting *
authority should be required to generate
ambient screening values and if
necessary, generate or have generated
data sufficient to develop a Tier n value
based on the protection of human health
from carcinogenic effects of pollutants.
The proposed Guidance in procedure
5.D.2 of appendix F also does not ., !
require the development of a Tier II
value for the protection of aquatic life
(except for those pollutants which are
.considered to be bioaccumulative
chemicals of concern) if the permittee
demonstrates through a biological _"j
assessment that there are no acute or
chronic effects on aquatic life in the
receiving water and that the, whole
effluent does not exhibit acute or
chronic toxicity based on the " '
requirements in procedure 6 of ,
appendix F. EPA has developed
guidance on conducting biological-.
assessments in Rapid Bioassessment
Protocols for Use in Streams and Rivers
(EPA/440/4-89/001, May 1.989), which
are available in the administrative
record for this rulemaking. EPA believes
that the results of a biological
assessment in conjunction with acute
and chronic toxicity tests serve as
available, relevant information for the
purposes of applying EPA's existing
regulation at 40 CFR 122.44(d)(l)(vi)(C).
This regulation allows permitting
authorities, in the absence of an , :
applicable numeric water quality
criterion to establish any necessary
WQBELs to control the pollutant by use
of an indicator parameter..In the case of
protection of aquatic life, EPA believes
that whole effluent toxicity can serve as
an indicator parameter in appropriate
circumstances. Whole effluent toxicity
measures the combined toxic effect of
all chemicals in an effluent. This .--..-
approach is. also consistent with EPA's
policy on independent'application of
water quality criteria discussed below
because this procedure is limited to
circumstances where whole effluent
toxicity requirements are not exceeded,
biological criteria are attained, and there
"are no data to develop a numeric
criterion for the pollutant of concern.
, Because there is no.analogous indicator
parameter for the protection of human
health and .wildlife, EPA has proposed
limiting application of this provision to
the protection of aquatic life. EPA
invites comment on all aspects of this
provision including the exception from
the requirement to generate data
necessary to derive Tier II values for the
protection of aquatic life if the permittee
demonstrates that biological
assessments have shown there are no
acute or chronic effects on aquatic life..
and the whole effluent toxicity does not
exhibit any acute or.chronic toxicity.
EPA also invites comment on the types
of information that comprise a valid
bioassessment, including whether
minimum requirements for conducting
these assessments should be specified in
the final Great Lakes Guidance. .
The proposed Guidance for procedure
5.D.2 of appendix F does not allow a
similar exception for bioconcentratable
chemicals of concern (BCCs) because
the use of whole effluent toxicity as an
indicator parameter may not be
appropriate for these pollutants. Whole
effluent toxicity measures the combined
effect of all toxic chemicals in an
effluent over the duration of the test.
The whole effluent toxicity test
methodologies published as guidance by
EPA .are conducted over a period of up
to eight days, hi contrast, the effects of
bioaccumulation of a pollutant on an
aquatic organism may not be observable
'within 30 days, and perhaps until the
end of the lifetime of the organism. For
this reason, EPA believes that whole
effluent toxicity tests may be
insufficient to identify significant toxic ;
effects of BCCs. EPA invites comment
on all aspects of this proposal including:
whether the exception should apply to
pollutants that have been identified as -•
BCCs.
Application of procedure 5.D.1 of
appendix F of the proposed Guidancels
only required for pollutants in Table 6.
The basis for selecting the pollutants hi;.'..
Table 6 is discussed in section n of the .
preamble, above. EPA believes that
requiring permitting authorities to
generate or have permittees generate :
ambient screening values and ' -
potentially Tier n values for all •...".
pollutants present ih;or known to be ,
discharged to the. Great Lakes may be
unnecessarily burdensome on regulated
discharges or permitting authorities.
EPA believes that limitation of :
procedure 5.D of appendix F to Table 6
pollutants is a reasonable means to .
improve uniform application of
minimum permitting requirements
^throughout the Great Lakes System for
the'pollutants of most concern to EPA ,
and the .Great Lakes States within these "
waters. Determinations of the
appropriate WQBEL for a pollutant not ,
identified in Table 6 will continue to be
made subject to the requirements in 40
CFR 122.44(d)(l)(vi) (A), (B), and (C). In
applying these regulations, permitting :
authorities may interpret State or Tribal
narrative, water quality-criteria by either
calculating site-specific numeric
criteria; applying EPA's water quality
guidance under section 304(a) of the
Clean Water Act, supplemented by other
relevant information; or establishing an
effluent limitation on an indicator
parameter for the pollutant of concern.
EPA .invites comment on all •.
requirements and exceptions in •'->'•
procedures 5.D.I and 5.D.2 of appendix
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
F including the procedure for
determining whether the permitting
authorities must generate or have the
permittee generate the data necessary to
derive Tier n values for the protection
of aquatic life, wildlife, and human
health for all pollutants known or
suspected to be present in discharges;
identification of procedures to minimize
the costs of this data generation on
permitting authorities and discharging
facilities; and identification of
procedures to minimize or eliminate
possible inequities between facilities ,
due to application of the data generated
by one facility to subsequent permitting
decisions regarding other dischargers.
Procedure 5.D.3 of appendix F of the
proposed Guidance states that, where
there is insufficient information to
develop a Tier n value, nothing in
procedure 5.D of appendix F precludes
or denies the right of a State or Tribe to
determine in the absence of the data
necessary lo derive a Tier I criterion or
a Tier n value, that the discharge of a
pollutant will cause, have the
reasonable potential to cause or
contribute to an excursion above the
State's narrative criterion for water
quality or incorporate a WQBEL for that
pollutant in a NPDES permit. This
provision is consistent with section 510
of the dean Water Act which expressly
retains the State's authority to adopt and
enforce standards, limitations or
requirements more stringent than those
in effect under the Clean Water Act.
Finally, proposed procedure 5.D.4 of
appendix F clarifies that if the
permitting authority develops a WQBEL
pursuant to procedure 5.D.3 of appendix
F under other more stringent authority,
it Is not obligated to generate or require
tha permittee to generate the data
necessary to derive a Tier n value for
that pollutant When a permitting
authority develops a WQBEL. the
WQBEL must achieve State water
quality standards including both
numeric and narrative water quality
criteria as required by 40 CFR
122.44(d)(l)(vii). As previously
discussed in the preamble, Tier n
criteria are tha permitting authority's
interpretation of narrative water quality
criteria. Therefore, if a permitting
authority establishes a WQBEL under
other more stringent authority when a
WQBEL is not mandated by procedure
S of appendix F, it is not also required
to apply the Tier H methodologies to
interpret that narrative water quality
criterion.
o. Consideration of Make Water
Pollutants When Determining
Reasonable Potential—-i. Introduction.
The proposed Guidance in appendix F,
procedure 5.A. through D., provides
procedures for permitting authorities to
determine if a discharge causes, has the
reasonable potential to cause or
contributes to an excursion above a
State or Tribal numeric or narrative
water quality criterion. These proposed
procedures require the permit authority
to establish water quality-based effluent
limitations upon determination that a
pollutant is or may be discharged at
sufficient levels to cause, have the
reasonable potential to cause or
contribute to an excursion above any
Tier I criterion or Tier II value.
The proposed procedures for
conducting reasonable potential
determinations in 5.A. through 5.D. do
not provide special considerations for
pollutants contained in a facility's"
intake water. In some'situations, the
sole or primary origin of a pollutant in
a discharge may be the'intake water for
a facility. For example, the origin of
many pollutants in once through
cooling water is the water body where
the facility obtains the water rather than
' a facility wastestream.
Procedure 5.E. of appendix F of the
proposed Guidance provides a separate
mechanism for permitting authorities to
consider the presence of intake water
pollutants in a facility's discharge when
determining the necessity for WQBELs.
Procedure 5.E. of appendix F would
allow the permitting authority to
determine that tha return of identified
intake water pollutants to the same body
of water under specified circumstances
does not have the reasonable potential
to cause or contribute to an exceedance
of water quality standards without
application of the reasonable potential
procedures set forth in procedure 5.A.
through 5.D of appendix F. Based on
this determination, the permitting
authority would not be required to
establish WQBELs for the identified
intake water pollutants. This procedure
would apply to facilities that return
unaltered intake water pollutants to the
same body of water without increasing
the mass loading rate or concentration
of the pollutant atthe edge of any
available mixing zone, and that do not
discharge the intake water pollutants at
a time or location that would cause
adverse water quality effects to occur
that would not have occurred if the
pollutants were left in place.
The proposed procedure would
supplement existing mechanisms to
modify technology-based effluent
limitations to reflect intake water
pollutants, and to derive appropriate
WQBELs for discharges to water that
exceed water quality criteria. These
mechanisms include Total Maximum
Daily Loads (TMDLs), temporary
variances from water quality standards,
modifications to designate uses, and
site-specific modifications to criteria.
Application of these existing
mechanisms to address intake water
pollutants is discussed below.
In addition to the proposed procedure
5.E of appendix F to part 132, EPA
considered four alternative options for,
addressing intake water pollutants. Each
of these options is discussed in more
detail in subsection e.iv below.
Option 1. Option 1 reflects the current
national approach. While EPA's existing
regulations do not provide for a special
credit for pollutants present in a
facility's intake water in the calculation
of WQBELs, several mechanisms are
available that may result in an
adjustment in a WQBEL to reflect the
presence of intake water pollutants (e.g.
TMDLs, temporary variances from water
quality standards, and changes in the
designated use of the water body or site-
specific criteria modifications). Option 1
would limit the regulatory procedures to
address intake water pollutants to these
existing mechanisms,, •
Option 2. In addition to allowing the
use of the procedures in Option 1,
Option 2 would allow a permitting
authority to modify WQBELs directly to
provide a full or partial credit for intake
water pollutants when the pollutants are
discharged to the same water body as
the intake water. A specified level of
credit would be allowed under this
approach even when the facility
contributes an additional amount of the
intake water pollutant from its process
waste stream. . • . •
Option 3. This option is similar to
Option 3, but it would also allow the
permitting authority to modify WQBELs
when the source, of the intake water is
different from the receiving water.
Option 4. This option is the initial
procedure developed by the Great Lakes
Technical Work Group. It is a
combination of Options 2 and 3 and
would provide a direct mechanism for
reflecting a credit, for pollutants in a
facUity's intake water under specified
circumstances.
Although the Great Lakes Steering .
Committee did not adopt the procedure
drafted by the Technical Work Group
(Option 4), it believed that the draft
Great Lakes Guidance should include a
provision addressing the discharge of
intake water pollutants to the Great
Lakes System. Accordingly, EPA agreed
to Convene a separate workgroup to
evaluate the extent to which permitting
authorities may consider the presence of
intake water pollutants during the
development of WQBELs. Proposed
procedure 5.E of appendix F reflects the
efforts of this workgroup. EPA requests
comment on all aspects of this subject,
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Federal Register / Vol. 58, No. 72 / Friday, April 16. 1993 / Proposed Rules
20953
including proposed procedure 5.33, all
issues raised in the preamble discussion
below, and any'suggested alternative
requirements or" combinations of
requirements to address the subject and
issues in the final rule.
iL Current National Approach—(A)
Net/Gross Credits for Technology-based
Limits. EPA's NPDES permitting
regulation at 40 CFR i22.45(g) currently
provides a mechanism for adjusting
treatment technology-based effluent
limitations to reflect credit for
pollutants in a discharger's intake water.
The regulation specifies the
circumstances under which EPA will
• adjust a facility's technology-based '
effluent limitation to account for the
presence of pollutants in a discharger's
intake water. The regulation provides
that technology-based limitations shall
be adjusted where the applicable
effluent limitations guidelines direct
limitations be applied on a net basis or
where the discharger demonstrates that
the presence of intake water pollutants
prevents compliance with the
applicable technology-based limitations
despite proper installation and
operation of the treatment systems. The
regulation also identifies four specific
conditions restricting the use of net
credits: •
(1) The regulation precludes lie use
of net credits for generic or indicator
pollutants unless the permittee
demonstrates that the constituents, of the
generic measure in the, effluent and
influent are substantially simikir or . . •
unless appropriate additional limits are
placed on process water pollutants.
(2) Credit may be granted only to the
extent necessary to meet the applicable
technology-based limitation, up to a'
, maximum value equal to the influent
value.
(3) Credit is generally limited to
discharges to the same body of water
from which the .intake water is drawn
although the Director may waive this
requirement if no.environmental
degradation will result. •
(4) Credit is precluded for return of
materials generated from the treatment
of intake water (e.g., raw water clarifier
sludge). • - • ; .
. The provision granting credit only to
the extent necessary to achieve a
technology-based limitation assures that
a discharger uses the appropriate
technology-based level of treatment (e.g.
BPT/BAT/BCT) in removing pollutants
that originate from the discharger's
facility. This provision in essence
•;assures the proper operation of
treatment technology.
In the promulgation of this "40 CFR
122.45(g), EPA declined to develop a
similar mechanism to adjust water
quality-based effluent limitations to
reflect credit for intake water pollutants.
EPA explained that "[i]he Clean Water
Act's requirement to protect and
enhance water-quality is not " .
conditioned on factors such as intake ;
waterqualityanditwould.be
inappropriate for EPA to impose such a
condition. Eligibility for a net credit
under these [technology-based]
regulations does not imply any right to
violate water quality standards." (49 FR
37998, 38027 (September 26,1984)).
EPA recognized the complexity of water
quality-based permitting, however, and
indicated that permit writers may take
the presence of intake water pollutants
into account, as appropriate, in
.individual permitting decisions. In all
cases, EPA noted that permit limits
"must be adequate to meet the water
quality objectives of the Clean Water -
Act when considered along with control,
requirements for other discharges to the
stream." (49 FR 38027 (September 26,
1984)). The existing mechanisms for .
simultaneously considering control
requirements for all dischargers to a
single body of water are total maximum
daily loads (TMDLs) and NPDES
permits written to implement these
TMDLs. The use of TMDLs to address
intake water pollutants is discussed -
further below,
(BJ Consideration-of Intake Water
Pollutants for Water Quality-based
Limits, Existing National regulations
and guidance allow the permitting
authority to utilize four mechanisms to
determine appropriate WQBELs when
the receiving water exceeds a water
quality criterion. These mechanisms
which are discussed below are total
maximum daily loads, variances,
removal of non-existing uses, and site-
specific modifications to water quality
criteria. ,
In addition to mechanisms, facilities
with intake water that contain
pollutants at concentrations above water
quality criteria.may be able to reduce
the level of these pollutants through
.pollution prevention measures.
Although pollution prevention is-a
voluntary action under the existing
NPDES permit program, pollution
prevention techniques can help reduce
the amount of a pollutant in an intake
water and therefore reduce the amount
of a pollutant that a facility may need
to discharge. For example, a facility
using groundwater contaminated with
DDT may be able to use an alternative
intake water source, such as a municipal
or surface water supply, that does not
contain this pollutant. Substitution of
an alternative source of intake water
may remove the necessity for or
decrease the stringency of any WQBEL
and improve the quality of the receiving
water body.
Another type of pollution prevention
involves source reduction within the
facility. One example of this approach is
a waste paper facility that discharges
PCBs (that are present in a process
waste stream and the' intake water
. source) to a receiving body of water that
already exceeds the criterion for PCBs,
By switching to a different source of
waste paper, one with less PCBs in the
ink, the facility maybe able to meets its <
WQBEL without having to install
additional treatment technology. This
type of source reduction is also
beneficial to the environment because '
the effluent would contain less PCBs, a
toxic bioaccumulative pollutant of
concern.
A second example of source reduction
within a facility is a utility with an
, effluent containing copper due at least
in part to corrosion from its copper
pipes at a level that would have a
reasonable potential to cause or
contribute to an exceedance of the '~
criterion for copper. The facility could
increase the hardness of the water that
passes through the copper pipes,
thereby reducing the amount of copper
in the effluent from corrosion. The
utility may then be able to comply with
any necessary WQBEL for copper
through this source reduction measure.
In addition to pollution prevention
efforts conducted by the facility,
regulatory authorities may utilize four
mechanisms to determine appropriate
WQBELs when the receiving water
exceeds a water quality criterion.
Regulatory authorities may:
(1) Develop an appropriate waste load
allocation for the discharger through a
TMDL that is designed to lead to
attainment of water quality standards,
pursuant to State requirements '
consistent with 40 CFR Part 130;
(2) Grant a "temporary variance from
water quality standards to an individual
discharger, pursuant to State
requirements consistent with 40 CFR
131.10 and 131.13;
(3) Remove a non-existing designated
use where unattainable and designate a
less stringent use and corresponding1
criteria to protect existing and/or
attainable uses pursuant to State
requirements consistent with 40 CFR
131.10; or
(4) Develop a site-specific criterion for
the water segment pursuant to State
requirements consistent with 40 CFR
If the permitting authority utilizes a
TMDL, a WQBEL for the pollutant may
be less stringent or unnecessary if the, '
TMDL provides for the attainment of
water quality standards .through load
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Federal Register / Vol. 58, No. 72/Friday, April 16, 1993 / Proposed Rules
reductions from other point or nonpoint
sources. If the pennitting authority
utilizes a variance from water quality
standards, a modified designated use or
a silo-specific criterion, a WQBEL for
tha pollutant may be less stringent than
the WQPEL necessary to meet the
original criterion or unnecessary to
reflect the temporary variance or change
in tho State water quality standards.
,,As discussed below, application of
one or more of these mechanisms may
bo appropriate to reflect the presence of
intake water pollutants above State
water quality criteria. All four existing
mechanisms can be applied whether toe
discharge is to a body of water meeting
or exceeding water quality standards,
and regardless of the intake water
quality. EPA offers this variety of
mechanisms because decisions whether
a WQBEL is necessary, and if so,
establishment of the appropriate level,
should be made on a case-by-case basis.
In some situations, one of these
mechanisms will provide a clear vehicle
for establishing appropriate WQBELs
whan background concentrations
exceed water quality standards. For
example, if the sole cause for non-
attainment of water quality criteria is
that the criteria do not reflect local
unique conditions, then a site-specific
criterion modification is the appropriate
mechanism. In other cases, compliance
with water quality standards may be
possible only with a combination of
mechanisms. Additional discussion of
those mechanisms is also contained in
the following preamble sections: section
Vffl.D., TotalMaximum Daily Load,
Wasteload Allocations Procedures;
section VEI.C, Variances from Water
Quality Standards; and section Vm.B,
Site-Specific Modifications to Criteria/
Values.
(1) TMDLs. Section 303[d) of the CWA
and 40 CFR 130.7 require States to
dovolop TMDLs for waters that are not
expected to meet applicable water
quality standards after existing
pollution control requirements
(Including technology-based controls)
are in place. A TMDL establishes the
total allowable pollutant load that can
exist in a body of water while
maintaining water quality standards; the
TMDL allocates this allowable load
among all pollutant sources. A TMDL is
tha sum of the waste load allocations
(point source load allocations), load
allocations (nonpoint source load
allocations), a margin of safety to
account for any uncertainties, and any
reserve capacity for future growth.
Pollutants in a facility's intake water
may originate from upstream point
sources or nonpoint sources (including
natural background). If the TMDL
provides for the attainment of water
quality standards through load
reductions from sources other than the
facility's discharge, a WQBEL may be
unnecessary for the facility's discharge
of intake water pollutants.
EPA interprets section 303(d) of the
Clean Water Act as requiring States to
develop TMDLs and begin requiring
pollution control even in the absence of
complete information. EPA's April
1991, Guidance for Water Quality-based
Decisions: The TMDL Process, which is
available in the administrative record
for this rulemaking, encourages a
phased approach to TMDL development
in situations where data are incomplete
or modelling is difficult. Under the
phased approach, a TMDL is developed
using all available information,
professional judgment, and a margin of
safety to account for uncertainties. The
TMDL includes a monitoring plan and
a schedule for assessing the attainment
of water quality standards after
implementation of the pollution
controls. The monitoring program acts
as a safeguard and, if water quality
standards are not attained after ,
implementation of the TMDL or it is
determined that allocations could be
larger without exceeding standards, the
data obtained through the monitoring
program can be used to develop a
revised TMDL.
Phased TMDLs can be effectively used
to address the presence of intake water
pollutants and to remedy violations of
existing water quality standards by
fairly allocating the burden of reducing
undesirable discharges among all
sources. An example where a phased
TMDL may be appropriate to address
intake water pollutants is a facility that
discharges mercury attributed to both its
intake water and process waste stream
to a water body that exceeds the water
quality criterion for mercury. The
sources of ambient mercury in the
intake water include upstream
permitted point source dischargers, and
releases from contaminated sediments.
A phased TMDL could reflect projected
iductions in mercury loads from a
re
required or scheduled sediment
remediation proje'ct and from reductions
in discharges from upstream point
sources. Under these circumstances, the
pennitting authority may determine that
a WQBEL for mercury for this facility is
unnecessary or should be less stringent
to reflect the projected load reductions.
Additional load reductions by this
facility beyond the capability of the
required treatment technology would
not be necessary if attainment of
standards could be achieved by these
other measures. The TMDL would
identify the implementation plan for
load reductions, document that these
actions are expected to attain water
quality standards based on predictive
water quality models, and in the case of
a phased TMDL, describe the plan for
implementation, monitoring, and
assessing whether standards are in fact
attained after implementation.
. Elimination or modification of
WQBELs based on a phased TMDL may
be available to dischargers whose intake
water contains pollutants for which the
water quality criteria are exceeded. The
phased approach for TMDLs is
discussed further in section VLI.D of the
preamble.
(2) Variances from Water. Quality
Standards. Second, States may currently
grant a temporary variance from water
quality standards to an individual
discharger pursuant to State
requirements consistent with 40 CFR
131.10 and 131.13 and National
guidance. The intent of a variance from
water quality standards is to provide a
mechanism by which a permit can be
written to meet an interim standard in
situations where short-term compliance
with the underlying non-attained water
quality standard is demonstrated not to
be feasible because of one or more of the
reasons listed in 40 CFR 131.10(g). In ,
addition, a variance from water quality
standards maintains the designated use
as a goal to be achieved in the long-term
instead of removing a use where the
current limiting conditions are
considered ultimately correctable.
Procedure 2.C of appendix F of the
proposed Guidance would allow the
Great Lakes States to continue to grant
variances for -the same reasons
recognized under the National program.
There are several conditions under
which variances from water quality
standards may be granted that are
appropriate to issues of background
water quality. For example, a State
could allow a variance under 40 CFR
- 131.10(g)(l) and proposed procedure
2.C.1 of appendix F when "naturally
occurring pollutant concentrations
prevent the attainment of the use"; 40
CFR 131.10(g)(3) and proposed
procedure 2.C.3 of appendix F when
"human caused conditions or sources of
pollution prevent the attainment of the
use and cannot be remedied or would
cause more environmental damage to
correct than to leave in place"; or 40
CFR 131.10(g)(6) and proposed
procedure 2.C.6 of appendix F when :
"controls more stringent than those
required by sections 301(b) and 306 of
the CWA would result in substantial
and widespread economic and social
impact.'' Such, variances may be
available to dischargers whose intake
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Federal Regiister / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rule?
20955
water contains pollutants for which the
water quality criteria are exceeded.
An example where a variance may be
appropriate is a situation where a
stream bed contains sediments upstream
of a permitted discharger contaminated
by a specified pollutant, Resuspension
of the contaminated sediments has
resulted in an exceedance of the water
quality criterion for the pollutant in-
: stream. Removing the sediments may
.cause more environmental damage than
to leave them in place for future .
remediation. The permitted facility
discharges effluent containing this
pollutant that is present hi both the
intake water and in its process waste
stream. By granting a variance and
calculating an interim water quality
criterion based on the current condition
of the water body reflecting the
background source of the pollutant, a
WQBEL for this discharge would be
established to meet this interim water
quality criterion. This approach should
still result in further improvement
towards attaining the existing water
quality standards..
Another example where a variance
may be appropriate is a utility company
with intake-water containing levels of
copper that exceed the applicable water
quality criterion. The facility's discharge
also contains a small amount of copper
due to corrosion of the facility's pipes.
Adding a treatment system to remove
the copper in the discharge to a level '
necessary to assure attainment of the
designated use or switching to an
alternative source of intake water might
increase facility costs substantially. If
those costs would result in large • ••-.
increases in utility rates in the area, they
could be considered to cause a
substantial and widespread social and
economic impact. By granting a variance
from water quality standards that
establishes an interim criterion for
copper that accounts for the background
level and the level of incidental removal
obtained by the discharger's proposed or
existing treatment systems, an NPDES
permit could be written which enr.ures
compliance with the interim criterion
without requiring additional treatment
by the facility. !
Another example where a variance
may be appropriate is a regional public
water supply with an intake water that
contains an ubiquitous pollutant which
is found in almost all water bodies in a
watershed at about the same
concentration due to watershed-wide
contributions from nonpoint sources,
and for which the concentrations exceed
the applicable water quality criterion.
Adding a treatment system to remove
the pollutant hi the discharge to a level
necessary to assure attainment of the
designated use might result in large
increases in utility rates in the area and
could be considered to cause a
substantial and widespread social and
economic impact. Also, switching to an
alternative source of intake water may.
not be practical because the pollutant
exists throughout the basin due to
nonpoint sources. By granting a
' variance from water quality standards
that establishes an interim criterion for
the pollutant that accounts for the
background level and the level of
incidental removal obtained by the
discharger's proposed or existing
, treatment systems, an NPDES permit
could be written which ensures
compliance with the interim criterion
without requiring additional treatment
by the facility.
The use of variances to address
discharges to water bodies exceeding
water quality standards within the Great
Lakes System is discussed further in
section Vm.C of the preamble.
(3) Modifications to Designated Uses,
"Third, States may currently remove a
non-existing designated use where
unattainable and adopt less stringent:
criteria to protect existing and/or
attainable uses pursuant to State
requirements consistent with 40 CFR
Part 131.10. This regulatory provision is
appropriate to address situations whe^e
the water quality standards for a water
body are not attainable hi the future. A
State may remove'a designated use that
is not an existing use if it can
demonstrate that attaining the use is not
feasible due to one or more of the six
factors,in 40 CFR 131.10(g). These are
the same factors for granting a variance
identified in EPA's existing guidance
and hi procedure 2 of appendix F of the
proposed rule. A State is required to
conduct a use attainability analysis in
accordance with 40 CFR 131.10 if the
revised uses are less than the fishable/
swimmable goals of the CWA specified
in section 101(a) or if the State adopts
Subcategories of uses specified in
section 101{a) which require less
stringent criteria. . ;>.
The proposed Guidance requires '
States to adopt specific numeric criteria
for the protection of human health that
' are equal to or more stringent than those
set forth in section 132.3, Table 3. All
of the criteria are calculated assuming
that the waters are used for fishing,
However, the Table includes both
cancer and non-cancer criteria that .
differ depending on whether the State
waters are designated for (or have
existing) drinking water uses. For many
pollutants the criteria are more stringent
for waters with drinking water uses, .-•••;
Thus, if States remove a non-existing
drinking water designated use for a
water body, the human health criteria
that would be required under the
proposed Guidance would be less
stringent for many chemicals than it
would be otherwise. Similar relief is
possible when the proposed human
health methodology is used to derive
criteria or values'for pollutants other
than those listed in Table 3.
Modifications of designated uses for
aquatic life and wildlife protection
would have no impact under the
proposed Guidance because the criteria
set forth in Tables 1, 2 and 4, and the
criteria and values developed pursuant
to methodologies referenced in § 132.4,
apply to waters of the Great Lakes basin
regardless of designated use. Site.'
specific modifications to acute and
chronic aquatic life criteria are available
in procedure 1 of appendix F of the
proposed Guidance hi those instances
where local water chemistry alters the
biological availability or toxicity of a
pollutant or where the sensitivity of the
local aquatic organisms differ
significantly from the species used to
develop the criteria. In addition, site
specific modifications to chronic "
aquatic life criteria are available in
procedure 1 of appendix F of the
proposed Guidance to reflect local
physical and hydrological conditions.
(4) Site-Specific Modifications to
Criteria. Fourth, a State or permittee
may develop site-specific criteria for a
water body. Site-specific modifications
need to be submitted to EPA for
approval or disapproval pursuant to
CWA section 303(c)(2). EPA guidance
on development of site-specific, aquatic
life criteria is contained hi Chapter 4 of
the U.S.EPA Water Quality Standards
Handbook, which is available in the
administrative record for this
rulemaking. The guidance provides for
site-specific adjustment of criteria when
(1) site water has different chemical
characteristics of water than the water
used in studies upon which the criteria
are based, where the differences have
been demonstrated to affect the
biological availability and/or toxicity of
a pollutant, or (2) the sensitivity of local
aquatic organisms (i.e. those that would
live in the water absent human-induced
pollution) differs significantly from the
sensitivity of species tested in <
developing the criterion.
Under the proposed Guidance, site-
specific modifications may result in *
either more or less stringent acute and
chronic aquatic life criteria, but may
result only in more stringent wildlife or
human health criteria. Accordingly, '
such modifications maybe available to
provide relief in situations involving
pollutants in intake waters where the
most stringent criterion for a pollutant
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20956
Federal Register / Vol. 58, No. 72 /Friday, April 16, 1993 / Proposed Rules
of concern is an acute or chronic aquatic
Ufa criterion. The bases a State may use
for justifying such less stringent criteria
are discussed in section VELA of the
preamble,
(5) Additional Examples of
Application of Existing Mechanisms.
Another example of the application of
existing mechanisms to address intake
water pollutants is a facility located on
a river that uses the river as both its
intake water source and receiving water
for the discharge. Contaminated
sediments amassed behind a dam on the
river are contributing to polynuclear
aromatic hydrocarbon (PAH)
concentrations that currently exceed the
State water quality criterion for PAHs.
The facility discharge includes PAHs
from both its process waste stream and
from the intake water.
Under Option 1, the permitting
authority would apply proposed
procedures 5.A through 5.D of appendix
F to determine whether the discharge
has the reasonable potential to cause or
contribute to the exceedance of water
quality standards. If reasonable
potential is demonstrated, the
permitting authority would need to
determine an appropriate WQBEL for
PAHs based on the existing State water
quality standards for this discharge to a
non-attainment water. At least two
exceptions to a WQBEL based on
existing State criteria, however, maybe '
available for this scenario for discharges
to the Great Lakes System under the
proposed Guidance. First, if the
contaminated sediments could not be
remedied in the near term or would
causa more environmental damage to
correct than to leave hi place, the
facility could request a temporary
variance from the water qualify criterion
under proposed procedure 2 of
appendix F of the proposed Guidance.
This would result in the facility
receiving a less stringent or no WQBEL
for PAHs in the discharge.
Second, if remediation of the
contaminated sediments was
technologically feasible, the appropriate
authority could develop a phased TMDL
under proposed procedure 3 of
appendix F of the proposed Guidance
based on available information,
professional judgment, and a margin of
safety to account for uncertainties.
Based on documentation of a required
implementation plan for remediation of
the contaminated sediments, the TMDL
could allot a larger wasteload allocation
to the facility to correspond to the
projected loading reductions to be
attained in a reasonable time period.
from sediment release. This would
result in either a less stringent or no
WQBEL for PAHs for the facility.
Additional examples of the use of
TMDLs, variances from standards, and
site-specific criteria modifications to
address pollutants from intake waters
exceeding water quality criteria are
contained in the discussion of those
procedures above..
iii. Proposed Guidance. Procedure 5.E
of appendix F of the proposed Guidance
provides a new procedure for
considering the presence of intake water
pollutants in water quality-based
permitting decisions in addition to the
available mechanisms described above.
The proposed Guidance would allow
the permitting authority to determine
that there is no reasonable potential for
the discharge of a particular intake
water pollutant to cause or contribute to
an excursion above a narrative or
numeric water quality criterion without
application of the procedures in
procedure 5. A through 5.D of appendix
F based on the permittee's
demonstration of specified conditions. If
these conditions are demonstrated, the
permitting authority would not be
required to include a WQBEL for the
pollutant in the facility's permit, If these
conditions are not satisfied, the
permitting authority would follow the
reasonable potential procedures in
procedure 5.A through 5.D of appendix
F to determine whether a WQBEL is
necessary for these discharges*
Proposed procedure 5.E of appendix F
was developed by a joint EPA and State
work group in 1992. Upon initial review
of the draft provision addressing intake
water pollutants developed by the Great
Lakes Technical Work Group (Option 4
in the preamble), EPA was concerned
that the provision may be inconsistent
with EPA's regulations and
interpretation of the CWA. These
concerns are expressed in the
discussion of Options 2, 3, and 4 below.
EPA formed a joint EPA and State work
group comprised of all ten EPA regional
offices, EPA's national office, and five
States to review the existing national
regulations to determine whether an
alternative option should be developed
to address intake water pollutants. This
work group identified and evaluated the
relevant technical factors and issues,
and drafted a procedure for determining
whether a discharge of intake water
pollutants would cause or contribute to
excursions above numeric or narrative
water quality criteria] Proposed
procedure 5.E of appendix F reflects the
efforts of that work group.
Proposed procedure 5.E. of appendix
F would provide a separate mechanism
for determining whether water quality-
based effluent limitations are necessary
for facilities that return unaltered intake
water pollutants to the source of the
intake water. EPA believes that the .
return of intake water pollutants to the
waters of the United States after removal
and use of the water by industrial
facilities is an addition of pollutants
subject to regulation under section 402
of the CWA. Once the water is removed
for use in industrial operations, it has
lost its status as waters of the United
States and the discharge must be
governed by appropriate conditions in
an NPDES permit, including any
limitations necessary to meet applicable
water quality standards. (See, NWFv,
Consumers Power, 862 F.2d 580, 589
(6th Cir. 1988), distinguishing
impoundment and subsequent release of
water at hydroelectric facilities which
generally is not subject to section 402
regulation from "the diversion of waters
of the United States by industrial
operations for cooling purposes in
which the water loses its status as water
of the United States". See also, NWF, Id.
at 585, distinguishing impoundment
and subsequent release of water at
hydroelectric facilities from discharges
from seafood processors which remove
fish from the waters of the United States
for processing and discharge the
•remaining fish materials back to the
waters of the U.S.; Association of Pacific
Fisheries v. EPA, 615 F.2d 794 (9th Cir.
1980), affirming in part, EPA's national
effluent guideline regulating discharges
from seafood processing facilities;
Rybachek vrEPA, 904 F. 2d 1276, "1285
(9th Cir. 1990), holding that
resuspension or redepositing of
materials discharged in placer mining,
including materials originally from the .
streambed or adjoining banks, is the
addition of pollutants; United States v.
M.C.C. of Florida, Inc., 772 F. 2d 1501,
1506 (llth Cir. 1985), holding that
redepositing of vegetation and sediment
by propellers of tugboat onto adjacent
sea grass beds is the addition of
pollutants; Avoyelles Sportsmen's
League v. Marsh, 715 F. 2d 897, 923- -
924 (5th Cir. 1983), holding that
redepositing of materials taken from
wetlands during land clearing activity is
the addition of pollutants.)
Industrial representatives have
previously argued that the discharge of '
intake water pollutants is not an
addition of pollutants subject to
regulation under the CWA and,
therefore, that EPA should provide for
simple subtraction of all amounts of
intake pollutants from any technology-.
based effluent standards. (49 FR 38025-
38027, September 26,1984; See also,
Appalachian Power v. Train, 545 F.2d
1351,1377 (4th Cir. 1977); American
Iron and Steel Institute v. EPA, 526 F.2d
1027 (3rd Cir. 1975)). EPA rejected these
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Federal Register /Vol. 58, No. 72 /Friday, April 16, 1993 7 Propdsed Rules 20957
arguments in the preamble supporting
the 1984 net-gross regulation for
technology-based limitations reasoning
that such subtraction was inappropriate
because treatment systems typically
reduce pollutants to a given level
despite variations in influent-
concentrations. EPA asserted that to
grant an absolute credit under these
circumstances: • ,
may give an unfair advantage to facilities
with measurable levels of pollutants in their
intake waters. Such facilities, by relying on
intake credits; could "comply" with effluent
limitations by utilizing a lower level of
treatment than their competitors on cleaner
streams—frequently a far lower level of
treatment than that designated by EPA as
BAT. (49 FR at 38026). : • -
Based on this reasoning, the final
regulation at 40 CFR 122.45(g) limited
the availability of credits for intake
water pollutants in calculating
technology-based limitations to the
specified conditions discussed in
subsection 5.E.2,e.ii.(A) above,
including that credit could only be
granted to •the extent necessary to meet
the applicable technology-based limit,
up to a maximum value equal to the
influent value. This requirement
generally precludes an,"absolute" credit
equal to the amount of pollutants in'the
intake water to the extent that these
pollutants can be removed through
proper operation and maintenance of
'the facility's control systems. EPA also
indicated-in the supporting preamble .
that such limitations on the availability
of net credits for calculating technology-
based limits comported with the Fourth
Circuit's decision in Appalachian
Power. Id., at 38027.. (See .also,
American Petroleum Institute v. EPA,
540 F.2d 1023 (10th Cir. 1976) and
Hooker Chemicals and Plastics v. Train,
537 F.2d 620 (2dCir. 1976) holding that
EPA's 1975 net-gross regulation was a
satisfactory answer to the argument that
all technology-based effluent limitations
must be expressed in net terms);
Although'challenges were also filed to
the 1984 regulation governing intake
credits for technology-based effluent
limitations, the United States Court of
Appeals for the District of Columbia
Circuit held that the rule was not ripe
for review until applied in a specific
permit. (NRDC v. EPA, 859 F.2d 156,
~ 204-205 (D.C. Cir. 1988).
Reliance on these decisions by
industry representatives to support an
argument that EPA is required to allow
net credits in the calculation of
WQBELs is also misplaced because of -
the fundamental differences between
technology-based and water quality-
based effluent limitations'under the
CWA. The authority for establishing the.
existing intake regulation is derived
generally from EPA's authority to
establish technology-based effluent
limits under sections 301, 304 and 306
of the CWA. Under those sections, EPA
must develop increasingly stringent
' effluent limitations based on the
improving technological capabilities of
treatment plants and economic
achievability. In developing a
mechanism for net credits in the
calculation of technology-based
limitations, EPA recognized that the
presence of pollutants in intake water
may prevent a facility in some , ;
circumstances from obtaining the .
statutorily mandated level of pollutant
removal (e.g.BPT, BAT orBCT). Under
• those circumstances, the failure to allow
adjustment of technology-based limits to
reflect the pollutants would in effect
' impose a higher, level of control than
statutorily required. As discussed
further above, three Circuits have
indicated'that the 1975 net credit
regulation provides an adequate
mechanism for addressing this problem
in the calculation of technology-based
limits. ', ;
The authority to establish WQBELs, in
contrast, is derived primarily from
section 301(b)(l)(C) of the CWA. This
section requires application of any more
stringent limitation necessary to meet
water quality standards after application
of technology-based controls. Legislative
history and judicial decisions have
emphasized the fundamental differences
and purposes of these two effluent
limitations, [See, House Debate H.R.
11896 (March 27,. 1972, Leg. Hist, at
* 375,379). See also, NRDC-v. EPA/859
F.2d 156, 210 (D.C. Chvl988), holding
that the CWA by virtue of .the important
differences between technology-based
and water quality-based standards, does
not require EPA to provide for an upset
defense to water quality-based permit
limitations violations and remanding for"
farther-proceedings}.
EPA has gained extensive technical,.
expertise in the two decades of NPDES
permitting on the nature of pollutants
and the effects of pollutants on waters
on the United States. Based on this
experience, EPA believes that
determinations whether a discharge of
intake water pollutants should be
limited by a WQBEL and, if so, the
scope of such limitations, must be •
determined after consideration of site-
specific factors. These factors include
consideration of the. applicable water
quality criteria, the quality of the
receiving water in relation to these .
criteria, additional pollutant loadings
from other point and non-point sources,
and evaluation of the facility's effluent.
As discussed further below, the effect of
the discharge4 of intake water pollutants
may also vary substantially depending '
on the location of the outfall in relation
to the intake point, the time interval
between intake and discharge of the
water, alterations of the pollutant by the
waste water treatment process, or
synergistic or additive interactions ; .
between the intake water and other .
waste water pollutants.
Additionally, EPA recognizes that
impairment of water quality is . "
determined not only by the magnitude
of a pollutant, but also by its chemical
nature in the environment. For example,
100 jig71 of lead in a dissolved form in
a river would likely cause a fish kill
whereas it rnay not if the lead was
tightly bound to suspended solids. With
regards to pollutants in a facility's
intake water, removal of 10 kg/day of
non-bioavailable lead and replacement
with 10 kg/day of bioavailable lead
"would place an additional stress upon
the receiving water.
; EPA believes that proposed procedure
5.E of appendix F would provide a
reasonable mechanism for evaluating .
the site-specific water quality effects
from the discharge of intake water "
pollutants. This procedure would allow
permitting authorities to conclude that
the return of unaltered intake water
pollutants to the same body of water
under identified ckcumstances does not
have the reasonable potential to cause or
contribute to an exceedance of water
quality standards. Under this procedure,
permitting authorities would not be
required to apply the reasonable
Eotential determination procedures, set
Drth in procedure 5.A. through 5.D of
appendix F or to establish a WQBEL to
control the discharge of an intake water
pollutant :
Proposed procedure 5 ,E of appendix F
would be applied on a pollutant-by-
pollutant and outfall-by-outfall basis.
For example, if a'facility takes in water
containing lead and copper, procedure .
5,E of appendix F would be available for
the parameter lead, even if the facility
contributes additional .copper to its
discharge from a waste' stream or other
source but does not contribute
additional lead or alter the lead in the
, intake water. The determination
whether a WQBEL would be necessary
for copper under these circumstances
would be made based on the procedures
in procedure 5.A through 5.D of
appendix F.
An example of the application of
proposed procedure 5.E of appendix F
is fora steam electric power plant with
once-through cooling water. In this
example, a steam electric facilityis
located downstream from a shoe
manufacturer that discharges bis(2-
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
ethylhexyl)phthalate. The steam electric
plant's intake water contains this
pollutant in a concentration that
exceeds the State water quality
criterion. The facility is able to
demonstrate that it does not contribute
an additional amount of this pollutant
from any source other than the intake
water; that the pollutant is not
concentrated at the edge of any mixing
zone or adversely altered in the process
of ones-through cooling prior to its
return to the same body of water; and
that the timing and location of the
effluent discharge does not cause
adverse impacts to occur that would not
occur if the pollutant was left instream.
This steam electric power plant would
qualify for a determination of no
reasonable potential for bis{2-
ethylhaxyDphthalate and would not
need a WQBEL for this pollutant.
The permittee would oe eligible for
the reasonable potential procedure in
proposed procedure 5.E of appendix F
upon demonstration of five conditions.
First, the permittee would need to
demonstrate that it withdraws 100
percent of the intake water containing
the pollutant from the same body of
water into which the discharge is made.
Facilities with multiple sources of
intake water that are not commingled
but discharged from separate outfalls
would be efigible for this new procedure
for any outfall(s) where 100 percent of
the intake water is drawn from the same
body of water into which the discharge
is made. Facilities with co-mingled
intake waters would also be eligible if
they could demonstrate that the
pollutant of concern is not present in
intake water withdrawn from any other
body of water. If the discharge from an
outiall includes intake water containing
the pollutant of concern from sources
other than the receiving water, the
permitting authority would instead need
to make a determination of reasonable
potential based on the procedures in
procedures 5.A through 5.D of appendix
EPA believes that restriction of
proposed procedure 5.E of appendix F
to dischargers to the same body of water
is appropriate to ensure consistency
with the structure and function of State
or Tribal water quality standards. Water
Duality standards include State
esignated uses and both narrative and
numeric criteria to ensure protection of
those uses foraspecified water body or
segment 40 CFR 131.3(i). The failure to
restrict this provision to discharges to
tha same body of water as the intake
source would allow the addition of
pollutants to a separate water body or
segment for the first time without
determining whether the new discharge
has the reasonable potential to cause or
contribute to an exceedance of
applicable water quality criteria based
on consideration of site-specific factors
including the condition of the receiving
water and contributions by other point
or non-point source discharges.
The restriction of proposed procedure
5.E of appendix F to the same body of
water is also consistent with the general
preclusion of credits for the discharge of
intake water pollutants to different
bodies of water when deriving
technology-based limitations under 40
CFR 122.45(g). As discussed further
above, this technology-based regulation
does not affect the discharger's
obligation to comply with any more
stringent limitations necessary to meet
the applicable water quality standards.
The regulation initially precluded credit
for intake water pollutants in deriving '
technology-based limitations under all
circumstances unless the permittee
demonstrated that the intake water was
drawn from the same body of water into
which the discharge was made (45 FR
33451, section 122.63(h)(l) (May 19, ,
1980)). hi 1982, EPA proposed to delete
the same body of water restriction for
calculating technology-based
limitations. Industry commenters
supported this proposal arguing that
limitations to implement water quality
standards would be sufficient to protect
receiving waters. Commenters opposed
to this proposal argued that limitations
based on water quality standards alone
were inadequate because States had not
developed numeric water quality
criteria for many toxic pollutants (47 FR
52081). In the final rule, EPA agreed
with commenters that many States had
not yet developed specific criteria for
many toxic pollutants and, therefore,
"meeting water quality standards [was]
not alone a sufficient condition for this
waiver." Based on this concern, EPA
retained the general preclusion of credit
for intake water pollutants from sources
other than the receiving water in the
calculation of technology-based
limitations, but allowed the Director to
waive the same body of water
requirement for those limitations if no
environmental degradation would result
from the discharge. (49 FR 38026
(September 26,1984)).
EPA invites comment on all aspects of
this condition including whether the
final Guidance should define the phrase
"same body of water" or allow
permitting authorities discretion to
interpret this phrase on a case-by-case
basis. As discussed further above, the
purpose of restricting the application of
proposed procedure 5.E of appendix F
to dischargers to the same body of water
is to ensure adequate evaluation of the
applicable water quality standards for
the receiving water and consideration of
the presence and amounts of other
sources of the pollutant. One option
under consideration is to define "same
body of water" to include water.
segments designated in State or Tribal
water quality standards. This approach
may result in inconsistent
determinations between permitting
agencies, however, particularly if there
are large variations in the size of the
designated individual water segments.
EPA requests comment on this
interpretation, including whether the
final Guidance should specify a
maximum limit to the size of the water
segment if this element is selected in. the
final Guidance.
Another possible approach would be
to allow permitting authorities the
flexibility to interpret "same body of
water" on a case-by-case basis. Factors
that might be considered in this
determination include whether the
intake and outfall points are within the
same water segment identified in State
or Tribal water quality standards;
whether the discharge is upstream or
downstream from the intake point in
, flowing waters or in close proximity to
the intake point in open lake waters;
. whether the intake pollutants would
reach the outfall point within a
reasonable time period in the absence of
the removal and discharge back to the
receiving.water; or whether the water
chemistry (e.g. hardness and pH) are ,
similar. Based on consideration of these
factors, for example, a permitting
authority might determine that a
discharge is to the same body • of water
where intake waters are taken from a
relatively clean tributary of a relatively
dirty body of water and discharged to
the latter body in close proximity to
where the tributary itself flows into the
larger water body. EPA also requests
comment on whether and, if so, under
what circumstances the phrase "same .
body of water" should be interpreted to
cover waters within the same
watershed. For example, should the
phrase "same body of water" encompass
intake waters taken from a relatively
clean water body and discharged into
another water body containing the
pollutant at higher concentrations
where both water bodies are within the
same watershed. EPA requests comment
on the interpretation of "same body of
water" and identification of any
additional factors that the permitting -
authority should evaluate in making this
determination. EPA also requests
comment on any alternative
interpretations of this phrase.
The second condition that the
permittee would need to demonstrate to
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20959
be eligible for procedure 5.E of ,-,
appendix F is that it does not contribute
any additional mass of the specified
intake water pollutant to its wastewater.
Contributions include pollutants
discharged to the process waste stream,
corroded from the facility's pipes, or ':
that are introduced from intake water
sources other than the receiving water.
The pollutant present in the discharge
must be due solely to its presence in
intake water from the receiving water
body.
EPA believes that this provision may
he necessary to implement the statutory
and regulatory requirements discussed
above, and to further the goals of'the
CWA and GLWQA to restore and
maintain, the physical, chemical and
biological integrity of the Nation's
waters. In non-attained waters,
restoration can only be achieved by
removal or natural degradation of past
pollutant loadings or by reduction hi •
future pollutant loadings. One
reasonable step towards restoration of
. non-attained waters is to limit
application of the proposed provisions .
of procedure 5.E.l?b. of appendix F to
"facilities that dp not contribute any
additional mass of a pollutant from its,
process waste stream. ..' • :
The determination whether the
discharge contributes an additional
mass of the intake water pollutant
should be based on monitoring data and
information on the kinds of pollutants
generated by the particular type of
facility. Forexample, a facility would
monitor the effluent flow.fvolume. per
day) and effluent pollutant :
concentration, and then wouldrcalculate
the mass of the pollutant'by multiplying
the effluent flow by a conversion factor
to transfer the, volume of water into
mass of water, and then multiplying by
.the concentration. If adequate data do
not exist to make this determination, the
, permitting authority would apply the
reasonable potential procedures in
procedure 5,A through 5.D of appendix
F. EPA invites comment on all aspects
of this provision including the
interpretation of "contribution of no
additional amount," the data discussed
for making,this determination, the use
of statistical methods to make this
determination, and whether minimum
data requirements should be specified
• in the final regulation.
The third condition the permittee
would need to demonstrate to he
eligible for proposed procedure 5.E of
' appendix Fis that it does not alter the
identified intake water pollutant
chemically or physically in a manner
that would cause adverse water quality
impacts to occur from the discharge that
would not occur if the pollutant was left
in-stream. Alterations may occur as long
as they do not cause adverse water
quality impacts. An example of the type
of alteration that would cause adverse
water quality impacts would be a '
change in pH or temperature that affects
the structure of some pollutants
contained in non-contact cooling water
such that the toxic effects associated
with the effluent pollutants are
increased. Another example is where a
facility reduces the hardness of its
water, thereby increasing the toxicity of
a metal. However, simple removal of a -
portion of the pollutants through
treatmentis not considered to be an
alteration that would cause adverse
water quality impacts. If the permittee
does not demonstrate to the satisfaction
of the permitting authority;that an
intake pollutant is not chemically or
physically altered in a manner that
would cause adverse water quality
impacts, the permitting authority must
determine the necessity for and level of
any appropriate WQBEL for the altered
pollutant according to the reasonable
potential procedures in procedures 5.A..
through 5.D of appendix F after
consideration of the individual facts.
EPA invites comment on all aspects of
this provision including the _.
interpretation of "chemical and physical
alteration," the interpretation of
"adverse water quality impacts", the
specific environmental and pollutant
parameters needing evaluation for
making this determination, the use of
statistical methods to make this
determination, and whether minimum
data requirements should be specified
in the final regulation. For example,
should the final rule include a list of
environmental parameters such as
hardness, pH, and percent of the
pollutant in the dissolved state for
determining if the pollutant is altered.
Also, should the final rule specify the
maximum extent to which these
environmental parameters can change
without causing an adverse impact on
water quality.
The fourth condition the permittee
would need to demonstrate to be
eligible for proposed procedure 5.E of '
appendix F is that the pollutant is not
concentrated at the edge of any available
mixing zone after discharge from the ,
facility. Attainment of water quality
standards generally is measured by
comparing the concentration of a
pollutant in an ambient water to the
water quality criterion which is
represented as a concentration. 'A non-
attained surface water is one where the
ambient concentration exceeds the
water quality criteria at the edge of a
mixing zone, if one is allowed by State
water quality standards, or at the end of
a discharge, pipe, if the water quality
pollutants at the edge of a mixing zone,
especially in non-attained waters, may
contribute to an, exceedance of water
quality standards. Accordingly,
: proposed procedure 5.E of appendix F
does not apply if there is an increase of
the pollutant concentration at the edge
.of a mixing zone as compared to the
pollutant concentration in the intake .:
water; if no mixing zone is allowed by
a State's water quality standards/the
appropriate comparison is instead to the
point of discharge. However, proposed
procedure 5.E of appendix F would
allow consideration of increased :
concentrations at the edge of any
allowable mixing zone to accommodate
water conservation in order to be
consistent "with the proposed provisions
in procedure 3 of appendix F that allow
the continued use of mixing zones when
water conservation measures would
result in increased pollutant
concentrations without increases in
mass loadings. EPA invites comment on
all aspects of this provision including
the interpretation of "no concentration";
whether a particular statistical
methodology for measuring "no
concentration" should be included in
the final Guidance; and whether any
provision in the final Guidance for
intake water pollutants should allow
consideration of a maximum increased
concentration resulting from
evaporation of cooling water.
The fifth condition that the permittee
would need to demonstrate to be
eligible for proposed procedure 5.E of
appendix F is that the timing and
location of the effluent discharge does
not cause adverse water quality impacts
to occur from the simple pass-through of
an intake water pollutant that would not
occurif the pollutant were left in-
stream. This, condition is designed to
protect the water body from adverse
impacts that could result if intake water
were withdrawn, for example, at high
flow conditions and discharged at low
flow conditions of at high tide and
' discharged at low tide. EPA is aware
that in some cases, differences due to
timing of the discharge would not cause
adverse water quality impacts, but
believes that there are some cases where
timing differences would cause adverse
impacts that must be considered by the
permitting authority.
This condition also ensures that the
location of the effluent discharge does
not cause adverse water quality impacts
to occur from the simple pass-through of
an intake water pollutant that would not
otherwise occur if the pollutant were
left in-stream. An example where there
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
may be an adverse water quality impact
is where the intake pipe is located mid-
stream, and the discharge is at the edge
of the river bank where there is a critical
habitat for a breeding population of fish.
Another example is where the intake
and outfall pipes are within the same
body of water but several miles apart.
The size of a water body segment
designated by the State or Tribe may
vary substantially. One large river
segment, for example, may contain both
portions that are in compliance with the
designated use and water quality
criteria, and portions that exceed
criteria due to other dischargers. Under
this circumstance, adverse impacts
might occur if the intake pipe was
located in the non-attainment portion of
the water body and the discharge was to
the higher quality water further
upstream. Accordingly, EPA believes
that the permitting authority should
evaluate the possibility of adverse
impacts due to the location of the intake
ana outfall pipes as a condition of
granting relief under proposed
procedure 5.E of appendix F. EPA
invites comment on all aspects of this
condition including whether the final
regulation should specify a maximum
distance between the intake and outfall
or a maximum time interval between
intake and discharge to be eligible for
proposed procedure 5.E of appendix F.
Proposed procedure 5.E. ol appendix
F of part 132 identifies three conditions
that the permitting authority must
address in the NPDES permit or fact
shoot if it determines under procedure
5.E of appendix F that simple pass-
through of an identified intake water,
pollutant does not have the reasonable
potential to cause or contribute to an
exceedance of a water quality standard.
. First, the permitting authority must
summarize the basis for the
determination that there is no
reasonable potential for the discharge of
an identified intake water pollutant to
causa or contribute to an excursion
above a narrative or numeric water
quality criterion within a State water
quality standard in the NPDES permit
fact sheet or statement of basis. This
would include evaluation of the
permittee's demonstration of the five
specified conditions discussed above.
Documentation of all calculations and
rationales is required by the existing
NPDES regulations at 40 CFR 124.7.
Second, proposed procedure 5.E of
appendix F would require that the
permit require all monitoring of the
influent, effluent and ambient water
necessary to determine that the
conditions of procedure 5.E of appendix
F are maintained during the permit
term. Appropriate monitoring is
necessary, for example, to identify
changes in the mass or concentration of
an intake water pollutant or
introduction of a new source of the"
identified pollutant through the
facility's waste stream. The selection of
appropriate monitoring requirements
may vary based on consideration of the
individual circumstances at each facility
or within the receiving water.
Accordingly, EPA believes that
permitting authorities should identify,
the appropriate monitoring parameters
and frequencies to be included in the
NPDES permit based on their best
professional judgment. EPA invites
comment on this condition, including'
whether the final Guidance should
specify minimum monitoring
requirements for all facilities, whether
permitting authorities should be
required to consider specified factors in
making this determination, or whether
other permit conditions would be
adequate in lieu of the proposed
monitoring provisions.
Third, proposed procedure 5.E of
appendix F would require that the
permit contain a reopener clause
authorizing the permitting authority to
modify or revoke and reissue the permit
if new information demonstrates
changes in any of the conditions of
procedure 5.E of appendix F. For
example, a facility may obtain a
different source of intake water or may
relocate its discharge into a different
receiving water. In these instances, new
amounts of pollutants are added to the
receiving water for the first time.
Similarly, monitoring may demonstrate
that an intake water pollutant is altered
by some change in the process waste
stream subsequent to permit issuance.
In either circumstance, the permitting
authority must evaluate whether a
WQBEL is necessary given the changed
circumstance, This condition is ' . , ,
consistent with EPA's authority to
modify permits for new information
under 40 CFR 122.62(a)(2).
The last part of the proposed language
for proposed procedure 5.E of appendix
F addresses the relationship between
the option and any available waste load
allocation CWLA) or total maximum
daily load (TMDL). The proposed
provisions of procedure 5.E of appendix
F do not alter the permitting authority's
existing obligation to develop effluent
limits consistent with the assumptions
and requirements of any WLA or TMDL
that is developed by the State and
approved by EPA. (40 CFR'
122.44(dKlXvii).)
Similarly, application of procedure
5.E of appendix F, if finalized, would
not alter a State's obligation to identify
water quality-limited segments and
establish priorities for conducting
TMDLs for those waters under 40 CFR
130.7. The required evaluation of
existing and available water quality data
to make these determinations under
existing § 130.7(b)(5) would include
consideration of the information
submitted or generated to support
permit decisions under procedure 5.E of
appendix F. .
If the permitting authority cannot
.make the determination under
procedure 5.E of appendix F for any
reason, then the permitting authority
would need to use the procedures under
procedure 5.A through 5.D of appendix
F for determining whether a discharge
has the reasonable potential to cause or
contribute to an exceedance of water
quality standards. Additionally,
ineligibility of a facility for the simple
pass-through determination of
procedure 5.E of appendix F would not
affect that facility's ability to request the
application of existing mechanisms for
consideration of intake water pollutants
in setting WQBELs (e.g., TMDL,
variance from water quality standards,
and modifications to designated uses
and criteria), described earlier in this
preamble and in other parts of this
Guidance.
Finally, § 132.4(g) of today's proposed
Guidance provides that the Great Lake
States and Tribes may,-but are not
required to, apply any of the proposed
implementation procedures to the
pollutants and pollutant parameters
listed in Table S of the proposed rule at
40 CFR part 132. EPA believes that
application of proposed procedure 5.E
of appendix F to the pollutants ha Table
5, including generic pollutant
parameters (e.g., biochemical oxygen
demand (BOD) and total suspended
solids (TSS)), is technically feasible as
long as the proposed requirements of
procedure 5.E of appendix F are
demonstrated. EPA invites comment on
the application of the procedures, to all
pollutants, including identification of
pollutant characteristics that may
prevent demonstration of any of the
proposed requirements of procedure 5.E
of appendix F.
iv. Alternative Options Considered.
EPA considered several options
described below that reflect
consideration of intake water pollutants
in establishing water quality-based
limits in addition to the proposed
approach. EPA requests comment onall
aspects of these alternative options.
(A) Option 1. Option 1 is the current
National approach. EPA's existing
regulations do not provide a specific
mechanism to allow special credit or
consideration for pollutants present in a
facility's intake water when setting
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Federal Register / Vol. 58, No. 72 /Friday, April 16, .1993 / Proposed Rules
20961
WQBELs comparable to the intake credit
provision for technology-based
limitations at 40 CFR 122.45{g). If the
permitting authority determines that a
facility's discharge has the reasonable
potential to cause or contribute to an
exceedance of water quality standards;
for any pollutant in the effluent, the
NPDES permit mustinclude-an
'appropriate WQBEL for that pollutant.
EPA's existing regulations and guidance
provide several mechanisms, however, -
that may be used to derive any WQBEL
necessary to control discharges of
pollutants to receiving waters that
exceed water quality standards,
including discharges containing .those
- poU^ants found in a discharger's intake
water. These mechanisms include
TMDLs, temporary variances from water
quality standards, and changes; in the
designated use of the water body or site-
specific criteria modifications. Each of
these mechanisms is described above. ,
Option 1 is the current EPA approach.
This approach forwards the CWA
section 101(a) goal of restoring the
physical, chemical and biological
integrity of the Nation's waters. It is also
consistent with requirements in CWA
section 3Ql(b)(l)(C) to include all
limitations necessary in NPDES permits'
to meet applicable State water quality
standards. Option 1 also creates an
incentive for regulatory authorities to
develop TMDLs for non-attainment
• waters consistent with the requirements
of CWA section 303(d). CWA section
303(d) is designed to remedy existing
in-stream excursions above State Water
quality standards and can be;used to
fairly allocate the burden of reducing
undesirable discharges among all
sources, point and ndnpoint. Finally,
Option 1 also allows use of temporary .
variances in the Great Lakes System to
the extent provided under National
regulations and site-specific criteria
.modifications to the extent described in
section VIILA above.
Some States have expressed concern
with the use of these existing
mechanisms/to address discharges of
intake water pollutants to non-
attainment waters. For example,
approval of a variance or site-specific
modification to a water quality criterion
requires time for public participation
and extends the duration of the permit
issuance process. In addition, .
completion and approval of a TMDL
may require additional time for
evaluation of available data and could
also extend the duration of the permit
issuance process. Delays in permit
issuance may impose additional costs •
on facilities and permitting .authorities.
Based on these concerns, the Initiative
Committees beh'eved that the proposed
Great Lakes Guidance should present
additional mechanisms to address
intake water pollutants. •., *
If EPA selects Option 1 in the final
Guidance, no regulatory language would
.be included to specifically address
intake water pollutants. EPA believes
that the existing mechanisms in, Option
1 generally" pro vide sufficient
procedures to address discharges to
non-attainment waters, including
discharges that contain intake water
pollutants. As discussed above, 7
however, EPA is also soliciting
comment on the adoption of proposed
procedure 5.E of appendix F to .
specifically address the simple pass-
through of unaltered intake water
pollutants in addition to continued
application of these existing
mechanisms,
(B) Option 2. EPA is also considering
whether to include a provision in the
final rule that would allow the
permitting authority to directly modify
WQBELs to reflect a credit for intake
water pollutants if the pollutants are- • .•
discharged to the same body of water as
the intake water. A specified level of
credit would be allowed under this
approach even when the facility
contributes an additional amount of the
intake water pollutant from its process
waste stream. However, credit would be
precluded under Option 2 if the facility
failed to demonstrate the remaining
conditions specified in section.S.E.l.a,
c, d, and e of proposed procedure 5.E of
appendix F. For example, credit would
be precluded under Option 2 similar to
the proposed procedure 5.E of appendix
F if the facility altered the identified
intake water pollutant chemically or
physically in a manner that would cause
adverse water quality impacts to occur
that would not have occurred if the - -
" pollutant was left uvstream;
concentrated the intake water pollutant
at the edge of the mixing zone (or end
of pipe if a mixing zone is prohibited)
as compared to the concentration in the
. intake; withdrew intake water from a
different body of water than the
receiving water; or discharged at a time
or location that may cause adverse
effects to occur that would not occur if
the pollutant was left'instream.
Option 2a would allow a facility to
discharge an effluent containing, at a
maximum, the same mass of the
pollutant withdrawn from the receiving
water. If a facility is able to remove any
of the pollutant from the intake water
either before use at the facility or during
waste water "treatment, the facility could
offset this reduction by increasing the
amount of the pollutant contributed by
the process wastewater. ••
Option 2b would allow a facility to
discharge an effluent containing, at a
maximum, the same mass of the
pollutant in the intake water after :
deduction of the amount removed by
the facility's treatment system prior to
use of the intake water in the facility.
This variation could result in a lower
discharge than allowed under option 2a.
If a facility removes any of the pollutant
originating in the intake water prior to
use at the facility, the facility would not
be able to offset this reduction. If a
facility is able to remove any of the
intake water pollutant during the
treatment process, however, it would be
able to increase the amount of the ,
pollutant contributed in the process
wastewater. The following scenario
demonstrates application of options 2a
and 2b. .
A facility is located on a river segment
with a lead concentration of 50 ug/L that
exceeds the State water quality criteria
of three ug/L. The facility withdraws
200,000,000 liters/day [53 million.
gallons/day) of water at a concentration,
of 50 ug/L; this corresponds to 10 kg/
day of lead in the intake water. The
facility treats its intake water prior to
use in the industrial process to remove
solids; this treatment removes 60
percent of the lead (six kg/day). The
facility's wastewater treatment system ^
removes 90 percent of lead from the
combination of the intake water and
process, waste water and "discharges the
remaining 10 percent.
Option 2a would allow the facility to
discharge an effluent containing the
same mass of lead withdrawn from the
receiving water, i.e., 10 kg/day of lead.
Under this scenario, the facility could
contribute 96 kg/day of lead from its
process waste stream prior to treatment
and still be able to discharge the-same
mass of lead withdrawn from the river*
that is, 10 kg/day. This calculation is
expressed as {10 kg- 6 kg + 96 kg)(Q.10)
= 10 kg.
Option 2b would allow the facility to
discharge an effluent containing the
same mass of lead withdrawn from the
receiving' water after deduction of the
amount removed by the facility prior to
use in the process stream, i.e., four kg/
day of lead. Under this seenario.'the
facility could contribute 36- kg/day of
lead from its process waste stream prior
to treatment. The facility would,
however, have the net environmental
benefit of removing six kg/day of lead
from the river even though it is
discharging pollutants that did not
originate from the receiving water. This
calculation is expressed as (10 kg—6 kg
+ 36 kg)(0.10) = 4 kg. The amount of
discharge allowed under Option 2b
would be greater for a facility that did;
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
not have to pretreat its intake water to
fulfill industrial process needs.
In developing NPDES permit
conditions under Option 2, a permitting
authority would need to require
sufficient information and monitoring of
the intake water quality to determine
tho appropriate WQJ3EL, including
information on the restrictions
identified as part of the proposed
procedure 5.E of appendix F (e.g.,
alteration of the pollutant, concentration
at tho edge of the mixing zone, and time
and location of the discharge). In
addition, the permitting authority
would need to require intake water
monitoring during the permit term to
determine if ambient concentrations
ducreast, and include a specific
reopancr provision In the permit to
allow the permit modification to
address any changed circumstances
including changed concentrations in the
intake water similar to the proposed
requirements of the proposed procedure
5£ of appendix F.
Finally, neither option 2a or 2b would
altar the authority of the regulatory or
permitting authority to develop
WQBBLs to account for the presence of
intake water pollutants pursuant to a
TMDL, temporary variance, or other
allowable modifications to water quality
standards pursuant to State and EPA
regulations and this proposed Guidance,
If a TMDL was developed, effluent
limitations derived using Option 2
would need to be adjusted so that the
TMDL was not exceeded.
Similarly, if EPA finalized a direct "
mechanism to modify WOjBELs to
reflect a credit for discharges containing
intake water pollutants, application of
this mechanism would not alter a State's
obligation to identify water quality-
limited segments and establish priorities
for conducting TMDLs for those waters
under 40 CFR 130.7. The required
evaluation of existing and available
water quality data to make these
determinations under existing
S 130.7(b)(5) would include
consideration of the information
submitted or generated to support these
permit decisions.
There are some advantages to this
option. In particular, this approach
%vould explicitly recognize that the
waiving water is the original source of
some or even all of the pollutants
discharged by the facility and provide a
direct mechanism for adjusting the
NPDES effluent limitations to reflect
this contribution from the intake water.
Option 2 does not require a facility to
remove constituents from the intake
water prior to discharging the water
back to the receiving water. The
mechanism provided by Option 2 would
not delay permit-issuance; in contrast,
the mechanisms available under EPA's
current regulations may delay permit
issuance as discussed in Option 1
above. This approach would at least
assure that current water column
concentrations that exceed either Tier I
criteria or Tier H values would not be ,
increased.
Further, EPA recognizes that in some
instances, Option 2 could result hi
reductions in water column
concentrations which may improve the
overall water quality. These instances
could occur where a facility discharges
less than the mass of a pollutant that it
removed from its intake water. For
example, if a facility's intake water
contained 10 kg/day of lead, the current
treatment system removed 6 kg/day of
the intake pollutant, and the facility
offset 3 kg/day of the removed amount
with waste stream pollutants (i.e., the
facility discharged 7 kg/day of lead), the
water quality may improve because of
the overall decrease in the mass of lead
in the water. Whether this discharge
would result in water quality
improvements, however, would depend
on several factors including the
magnitude of the actual decrease in the
pollutant concentration in the water
column, the lowered concentration in
the water column as compared to the ,
Water quality criterion, and
consideration of the factors identified in
the proposed procedure 5.E of appendix
F (e.g., alteration of the pollutant,
concentration at the edge of any
applicable mixing "zone, and time and
location of the discharge).
EPA has several concerns, however,
about Options 2a and 2b. First, both
options 2a and 2b may be viewed as
inconsistent with the CWA and GLWQA
goals of restoring the physical, chemical
and biological integrity of the Nation's
waters. In non-attained waters,
restoration Can only be achieved by
removal or natural degradation of past
pollutant loadings or by reduction in
future pollutant loadings. Option 2a
does not produce any further reduction
in pollutant levels because the facility
may discharge waste stream pollutants
up to the total pollutant mass in the
intake water. Option 2b provides some
reduction because any pollutant mass
removed by a facility prior to use of the
intake water in the process system
cannot be returned to the surface water.
However, option 2b also allows any
further removal of pollutants by the
facility's wastewater treatment system to
be replaced by an increased discharge of
the pollutants from the process waste
stream. Therefore, both options allow
offset of incidental removal of
pollutants in whole or in part by
contributions from facility discharges.
Second, Option 2 may be interpreted
as inconsistent with EPA's existing
regulation of intake water pollutants for
technology-based limitations. The
NPDES regulation at 40 CFR
122.45(g)(3) provides that the credit
shall be granted "only to the extent
necessary to meet the applicable
limitation or standard up to the influent
value." This regulation does not provide
full credit in the calculation of
technology-based limitations for all
pollutants contained in intake water,
but instead precludes credit for
pollutants removed by the existing or
proposed intake and effluent treatment
systems.
In the preamble to the final
rulemaking promulgating 40 CFR
122.45(g)(3), EPA discussed a comment
that asserted that a simple subtraction of
intake pollutant values from effluent
values should be made when setting
technology-based permit limits and
measuring compliance. EPA rejected
this argument in part because:
To grant a net/gross credit may give an
unfair advantage to facilities with measurable
levels of pollutants in their intake waters.
Such facilities, by relying on intake credits,
could "comply" with effluent limitations by
utilizing a lower level of treatment than their
competitors on cleaner streams * * *.
Furthermore, intake pollutants rarely pass
through a facility and all its associated intake"
and/or effluent treatment without some
removal and/or complicated exchange of
pollutants* * *. [T]he current regulation
* * * does not allow a full credit, but only'
a credit after consideration of removal in ,
intake and effluent treatment systems.
Today's regulation replaces that complicated
calculation with a more simple approach of
granting credit as .needed to meet technology-
based standards. (49 FR 38026 (September
26,1984));
Option 2 could be viewed as
inconsistent with this position by
allowing facilities to replace pollutants
removed by treatment of the effluent
(and, under option 2a, treatment of the
influent as well) with additional
pollutants from their process waste
stream prior to discharge.
Additionally, although adjustment of
technology-based limits is appropriate
to reflect intake water pollutants under
narrow circumstances, EPA believes
that a similar direct credit provision to
adjust WQBELS may not be appropriate
because of the fundamental differences,
between the two types of permit
limitations. The authority for
establishing the existing intake
regulation is derived from EPA's
authority to establish technology-based
effluent limitations under sections 301,
304, and 306 of the CWA. Under those
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Federal Register /Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules 20963
sections, EPA must develop increasingly
stringent effluent limitations based on
the improving technological capabilities
of treatment plants. In developing this
mechanism to ad just technology-based
effluent limitations, EPA recognized
that the presence of pollutants in intake
water may in some circumstances
prevent a facility from obtaining the
statutorily mandated level of pollutant
removal (e.g., BPT, BAT, orBCT). Under
those circumstances, the failure to allow
adjustment of technology-based •
limitations to reflect the pollutants,
would in effect impose a higher level of
control than statutorily required. The
authority to establish WQBELs, in
contrast, is derived primarily from
section 30lCb)(l)(C). This getStion
requires application of "any more
stringent limitation * * * necessary to
meet water quality standards" after
application'of technology-based
controls. - "
Third, EPA is concerned that both
options 2a and 2b would allow facilities
to discharge pollutants originating from
a process waste stream into a surface
receiving water that currently exceeds
an applicable water quality criterion. In
the absence of a temporary variance
from existing water quality standards,
site-specific modifications to criteria or
designated uses, or an appropriate
wasteload allocation pursuant to a
TMDL, EPA believes that the permitting
authority should establish appropriate
WQBELs to control discharge from
process wastewaters if they have the
reasonable potential to cause or s. ". •.
contribute to an exceedance of existing
State water quality standards. -
Fourth, Option 2 may create an
economic incentive for facilities to
relocate to water bodies that are the
most polluted, that is, have the highest
ambient pollutant concentrations.
Under both options 2a and 2b, the
amount of a pollutant that a facility.
could discharge is not based solely on
attainment of water .quality standards; in
these cases, the amount of the pollutant
currently in the receiving water and the
efficiency of the facility's treatment
systems also affectthe effluent
limitations. Wastewater treatment
systems generally are able to remove a
set percentage of a pollutant mass in the
influent to the wastewater treatment
system. (There are exceptions to this
general concept but these occur when
the influent concentrations are greatly
dissimilar, e.g., one influent
concentration is near the analytical
method detection limit and the other is
greater by a factor of 10 or more.) As a
result, the higher the ambient pollutant
concentration, the greater the pollutant
. mass that alacility could discharge."
In the previous example used to
describe Option 2a, the facility removed
10 kg/day of lead from the-river and was
able to contribute 96 kg/day from its
process wastewater in order to achieve
a discharge requirement of 10 kg/day. If
the concentration in the river at the
intake was double (160 ug/i), Option 2a
would allow the facility.to discharge
more of the pollutant (20 kg/day of
lead). Under this condition of a higher
concentration in the intake water, the
facility could contribute 192 kg/day of
lead from its process waste stream, prior
to treatment. This calculation is
expressed as (20 kg—12 kgf192
kg)(0.10)=20 kg. Therefore, the higher
.the pollutant concentration in the
receiving water, the more of that
pollutant that the facility can contribute
from its process wastewater under
Option 2a before it is treated and still
discharge the same mass of lead
withdrawn from the river.
The same principle holds for Option
2b', Under the example used to describe
Option 2b, the facility is able to
discharge 4 kg/day of lead which '>
represents the mass removed from the
river by the intake after discounting the
amount removed by the facility prior to
use,in the process. The facility was able
to contribute 36 kg/day from its process
wastewater in order to achieve a ,
discharge requirement of 4 kg/day. If the
concentration in the river at the intake -.
was double (100 Hg/L), Option 2b would
allow the facility to discharge more of
the pollutant (8 kg/day of lead). Under
this condition of a higher concentration
in the intake water.'the facility could
contribute 72 kg/day of lead from its
process waste stream prior to treatment.
This calculation is expressed as (20
kg -12 kg + 72 kgKO.10) = 8 kg.
Therefore, the higher the pollutant
concentration in the receiving water, the
more of that pollutant that the facility
can contribute from its process
wastewater under Option 2b before it is
treated and still discharge the same
mass of lead withdrawn from the river
less the amount removed by the facility
prior to use in the process*
EPA is concerned that any incentive
for facilities to relocate to surface waters
that are more polluted may be
interpreted as inconsistent with the
shared goal of the CWA and the
GLWQA to restore the physical,
chemical and biological integrity of the
Nation's waters. In non-attained surface
waters, restoration can only be achieved
by removal or natural degradation of
past pollutant loadings or reduction in
future pollutant loadings. Creating an
incentive for facilities to relocate to non-
attained waters may delay or frustrate
achievement of this goal. ,
EPA requests comment on all aspects
of Option 2, including whether any
. consideration of this approach should
be limited to intake water pollutant
discharges that result in a minimum
specified decrease in the total mass of
the pollutant in the receiving water and/
or improvement in water quality. EPA
also requests comment on the '
conditions that would be necessary to:
demonstrate improvement in water
quality under these circumstances; any
appropriate methods for determining
decreases io. total pollutant mass; and .
whether a specified minimum level of
decrease should be required for this
option. For example, should this
approach, if adopted, specify a
minimum percent reduction in the
ambient concentration of the pollutant
or require that the ambient
concentration after discharge be within
a certain percentage of the water quality
criterion.
Finally, EPA requests comment on
whether application of a mechanism to
modify WQBELs to directly reflect
credit for intake water pollutants, if
adopted, should be limited to one
permit term (a maximum of five years)
absent State completion of a TMDL for
the water quality-impaired receiving
water. As discussed further above,
existing § 130.7 currently requires States
to identify water quality-limited
segments and establish priorities for
conducting TMDLs for those -waters. A
time limitation on the availability of ,
intake credits un^er Option 2 may
facilitate restoration of water quality-
limited segments by encouraging timely
development of appropriate wasteload
allocations .and load allocations for all
discharges into these impaired waters.
EPA requests comment on this
limitation, including the reasonableness
of a restriction to one permit term, and
on all other aspects of Option 2.
(C) Option 3. EPA considered another
option that would allow the permitting
authority to directly modify WQBELs to
reflect a credit for intake water
pollutants regardless of where the intake
water source is located. Option 3 is
similar to Option 2 in all'aspects except
that Option 3 extends the concept of
intake credits for WQBELS to situations
where all or a portion of the intake
.. water source is a different body of water
than the receiving water. EPA
considered three variations to this r
option.
Option 3a would allow a facility to ,
discharge an effluent containing, at'a
maximum, the same mass of the, • ;
pollutant that the facility receives from
any water source including sources
other than the receiving water. If a ; .
facility is able to remove any of the
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
pollutant from the intake water, the
facility could offset this reduction by
increasing the amount of the pollutant
contributed by the process wastewater.
Option 3b woula similarly allow a
facility to discharge an effluent
containing, at a maximum, the same
mass of the pollutant contained in
intake water from any source after
deduction of the amount removed by
tha facility's treatment system prior to
uso of the intake water in the facility. If
a facility is able to remove any of the
pollutant originating in any intake water
through wastewater treatment, the
facility could similarly offset this
reduction by increasing the amount of
tha pollutant contributed by the process
wastewater.
Option 3c would allow a facility to
discharge an effluent containing, at a
maximum, the same concentration of
the pollutant that Is present in the
raceiving water. If a facility is able to
romova any of the pollutant from the
intake water, the facility will be able to
offset this reduction by increasing the
amount of the pollutant contributed by
the process wastewater. The following
scenario demonstrates application of
options 3a, 3b, and 3c.
A facility is located on a river segment
with a lead concentration of 50 ug/L that
exceflds the State water quality criteria
of three Ug/L. The facility obtains
200,000,000 liters/day (53 million „
gallons/day) of water at a concentration
of 10 ug/L from a nearby lake; this
corresponds to two kg/day of lead in the
intake water. The facility treats its
intake water prior to use in the
industrial process to remove solids; this
treatment removes 60% of the lead (1.2
kg/day). The facility's wastewater
treatment system removes 90 percent of
lead from the combination of the intake
water and process wastewater and
thereby discharges the remaining 10
percent.
Option 3a would allow the facility to
discharge an effluent to the river which
contains the same mass of lead in the
water removed from the lake, i.e., two
kg/day of lead from the lake. Under this
scenario, the facility could contribute
19.2 kg/day of lead from its process
waste stream prior to treatment. This
calculation is expressed as (2 kg-1.2
kg*19.2 kg)(0.10]=2 kg. This discharge
also would increase the lead mass in the
river by two kg/day.
Option 3b would allow the facility to
discharge an effluent to the river which
contains the same mass of lead
withdrawn from the lake after deduction
of the amount removed by the facility
prior to use in the process stream, i.e.,
0.8 kg/day of lead. Under this scenario,
the facility could therefore contribute
7.2 kg/day of lead from its process waste
stream prior to treatment. This
calculation is expressed as (2 kg—,1.2
kg+7.2 kg)(0.10)=0.8 kg. This also would
increase the mass in the river by 0,8 kg/
day.
Option 3c would allow the facility to
discharge an effluent to the river which
contains the same concentration of lead
as in the receiving water. In the
example, the river has a concentration
of 50 ug/1. The facility would be able to
discharge 10 kg/day of lead to the river
which represents a discharge of
200,000,000 I/day at a concentration of
50 ug/1. Under this scenario, the facility
could contribute 99.2 kg/day of lead
from its process waste stream prior to
treatment. This calculation is expressed
as (2 kg-1.2 kg+99.2 kg)(0.10)=10 kg.
This discharge also would increase the
lead mass in the river by 10 kg/day.
In developing NPDES permit
conditions under Option 3, as with
Option 2, a permitting authority would
need to require sufficient monitoring of
the intake water quality to determine
eligibility for and compliance with
appropriate WQBELs and incorporate a
specific reopener provision in the
permit to allow permit modification to
address any changes in the ambient
concentration of the pollutant. Also
consistent with Option 2, Options 3a,
3b, and 3c would not alter the authority
of the regulatory or permitting authority
to develop WQBELs to account for the
presence of intake water pollutants
pursuant to a TMDL, temporary
variance, or other allowable ,. ' •
modifications to water quality standards
pursuant to State and EPA regulations
and this proposed Guidance, If a TMDL
was developed, effluent limitations
derived using Option 3a, 3b, or 3c
would need to be adjusted so that the •.
TMDL was not exceeded.
Option 3 has the same advantages as
identified above for Option 2. In
particular, the option would recognize
that the intake water is the original
source of some or all of the pollutants
discharged by the facility and provides
a direct mechanism for adjusting the
facility permit limits to reflect this,
contribution. For example, where a
facility receives its intake water from a
commercial or public water supplier,
this approach allows the facility to
discharge into the receiving water the
same amount of pollutants, either
treated or untreated, as present in the
intake water.
EPA recognizes that in some instances
Option 3 could result in reductions in
water column concentrations which
may improve the overall water quality.
These instances could occur if a facility
discharges less than the concentration of
a pollutant that is present in the
receiving water. For example, if a
facility discharged an effluent
containing 10 ug/1 of lead into a river
with a concentration of 50 ug/1, the
discharge may dilute the ambient
concentration and therefore lower the
river concentration. Although the
ambient concentration could be lower,
however, the mass of a pollutant would
increase by the transfer of pollutants to
a different body of water. Whether this
discharge would result in overall water
quality improvements would depend on
several factors including, the magnitude
of the actual decrease in the pollutant
concentration in the water column, the
lowered concentration in the water
column as compared to the water
quality criterion, consideration of the
factors identified under the proposed
procedure 5.E of appendix F (e.g.,
alteration of the pollutant, concentration
at the edge of any applicable mixing
zone, and time and location of the
discharge), the impacts of additional
mass on pollutant levels in sediment
and fish tissue, and the transfer of the
additional mass through volatilization "•
and sedimentation into nonpoint
sources of atmospheric deposition and
sediment resuspension. In particular,
the additional mass of a persistent
pollutant may offset some of the
environmental benefits of lowering
water concentrations because the
additional mass, if cycled through
sediments by deposition and
resuspension, could delay the date of
achieving the water quality criterion.
EPA has several concerns, however,
with options 3a, 3b or 3c of the
proposed Guidance. In addition to the
reasons discussed for options 2a and 2b,
options 3a, 3b and 3c would allow '
facilities to increase the mass of
pollutants in a surface receiving water
that currently exceeds an applicable
water quality criterion. Under Option 3,
the pollutants in the intake water
originated from outside the water body
and would otherwise not be introduced
into the receiving water except for the
discharge of the facility. The approach
of Option 3 therefore may be interpreted
as inconsistent with the CWA and
GLWQA goals of restoring the physical,
chemical and biological integrity of the
Nation's waters. In non-attained waters,
restoration can only be achieved by
removal or natural degradation of jpast
pollutant loadings or by reduction in
future pollutant loadings. Options 3a, 3b
and 3c increase the pollutant levels by
increasing the pollutant mass in the
receiving water.
Option 3 is also inconsistent with the
structure and function of State water
quality standards under the CWA. Water
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20965
[uality standards include Stata ,
lesignated uses and criteria to ensure
protection of those uses for a specified
water body or water segment, dption 3
would allow facilities to introduce
pollutants from a different body of water
for the first time without determining
whether the new discharge has the .
reasonable potential to cause or
contribute to an exceedance. of .
applicable water quality criteria for the
receiving water. '
EPA requests comment on all aspects
of Option 3, including whether any
consideration of this approach should
be limited to-intake water pollutant
discharges that result in a specified
minimum decrease in the concentration
of the pollutant in the receiving water
and/or improvement in water quality..
EPA also requests comment on the
conditions that would be necessary to
demonstrate improvement in water
quality under these circumstances; any
appropriate methods for restricting
' increases in total pollutant mass; and .
whether a specified maximum level of
mass increase should be required for
this option. EPA also requests comment
on whether this option should only be
considered for .those pollutants that do
not bioconcentrate in aquatic organism
tissue or accumulate in sediments. For
example, should this approach if
'adopted specify a minimum percent
reduction in the ambient Sjpncijntration
of the pollutant or require that the
ambient concentration after discharge be
within a certain percentage of the water
quality criterion or'require a maximum
allowable increase in title mass loading
to the water. •
(D) Option 4. This option is;the initial
procedure developed by the Gifeat Lakes
Technical Work Group during the
Initiative process. Option 4 is presented
below in its entirety from the December
6,1991 version. This version was
originally included in the Great Lakes
. Implementation Guidance as. Part, ll.B t
(now procedure 3 of appendix F to part
,132) and is listed below; .
•••-••>.•.• • :,' '• ' ' '•• ^ .' ••
B. Background concentrations greater thpn
the water quality standard or criteria. This
• section includes provisions for determining ,
effluent limitations when the. background .
concentration of a pollutant in a receiving
water exceeds an applicable water quality
standard or criterion. In applying these
, provisions.'hdwever, all effluent limitations
.derived by this provision must not cause any
applicable TMDL to be exceeded. In such .
cases, the effluent limitations, shall be
adjusted so that the TMDL is not exceeded.
(1) Point sources using water from a source
other than the water body to which the
'effluent is discharged.
(a) Whenever the representative
background concentration for a toxic
substance in- the receiving.: water is '
determined to be greater than any applicable
water quality standard or criterion for that.
substance and the source of at least 90
percent of the Wastewater is from
groundwater or a public drinking water
supply system, the concentration value of the
WLA for that substance, shall be equal to the
lowest applicable water quality standard or
.criterion except as provided by part B,(l)(b).
POTWs which discharge to the same surface
water from which the water supply is
withdrawn shall be subject to .part B(2). of
this procedure.
(b) The concentration value of the WLA
"may be established at a concentration greater
than the water quality standard or criterion
for the substance in the receiving water as '
required by part B.(l)(a) in a range up to, but
• not greater than the representative
concentration of the substance hi the •
receiving water. The WLA shall only be
increased above the standard or criterion if
it is demonstrated to the permitting agency
that the concentration of the substance in the
groundwater or public, drinking water-supply
system at the point of intake exceeds that
applicable standard or criterion for that
substance and that reasonable, practical or
otherwise required methods are implemented
• to minimize the addition of the toxic
substance to the wastewater. This part shall
not apply where groundwater is withdrawn
from a location of contaminated
groundwater. . '
(2) Point sourcesusing water from the
same water body to which the effluent is
discharged.
fa) Whenever the representative :
background concentration bt a toxic
substance in the receiving water is
determined to be greater than any applicable
water quality standard or criterion for that
substance and the source of more than 10
percent of the wastewater for any discharger
is from the same receiving water, the
concentration value of the WLA for that
substance shall equal the representative
background of that substance in the receiving
water. In addition, or as an alternative, the '
mass value of the WLA may be established
at a value which requires that there be no net
addition of the. toxic substance in the
wastewater as compared to;the intake or
source water. ..._..
. Option 4 represents a combination of
Options 2a and 3c. The procedure
provides mechanisms for reflecting a
credit for pollutants in a facility's intake
water under two circumstances.
First, when at least 90 percent of the
intake water source is from ground
water or public drinking water supply,
Option 4 would allow a facility to .
discharge an effluent containing a
concentration of a pollutant ranging
from, at the low end, the water quality
criterion, to, at the high end, the _
.concentration of the pollutant in the '•
receiving water. The permitting ,
authority would use its professional
judgment and Would consider the
reasonable, practical, and required
methods to minimize addition of toxics,
in deciding where to establish the
effluent limitation within the range of
possible effluent limitations; .
. Second, when a minimum of 10
percent of wastewater is from the same
water body into which the effluent is
discharged, Option 4 would allow a
facility to discharge an effluent at a
concentration equal to the receiving
water or containing a mass of a
pollutant equal to the mass the facility
receives from the water body. This .
. option would apply even if 90 percent
of the wastewater is from the process
waste stream or from waters other than
the receiving stream. - .
The same scenarios used to illustrate
options 2a and 3c and permitting > :
considerations can also be used to
illustrate application of this option; EPA
has concerns about Option 4 in the
proposed Guidance similar to those , •
expressed above for options 2a and'Sc.
In addition, the requirement that
effluent limitations must be consistent ,
with the provisions of a TMDL is not
sufficient to resolve the deficiencies of
this option. There is no guarantee that
a TMDL will be developed for any
particular water body that accounts for
all significant point and nonpoint
sources and the option alone does not
, ensure attainment of water quality
standards in the receiving waters.
EPA is also concerned that Option 4
would not prevent facilities-from
discharging pollutants that, although ,
. equal in mass to that in the intake waterV
may be biologically more active and
thereby cause a greater adverse impact
on the receiving water than leaving the :
pollutants in place. As previously
discussed, EPA recognizes that ;
impairment of water quality is
determined by both the magnitude of a •.-
pollutant and.its chemical affects on the
environment. This led to the proposal of
the provisions of proposed procedure
5 .E of appendix F that a facility not
contribute additional mass of the
pollutant, or alter an intake water
pollutant chemically or physically, or '
discharge at a time or location that may
cause adverse impacts to occur which ;
would not occur absent removal akd
redischarge of the pollutants. ,
Finally, EPA recognizes that in some ;
instances Option 4 could result in-
reductions in water column
concentrations which.may improve the
overall water quality in circumstances
and for reasons identical to those :';-'
discussed previously for Option 3. EPA
requests comment on all* aspects of
Option 4, including the issues identified
for comment under Options 2 and 3.
v. Request for Public Comment. EPA.
invites public comment on all aspects of
.the proposed Guidance and all other, •.-..•.•
options: for procedure 5,.Eof appendix.F
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
for determining whether a discharge has
the reasonable potential to cause or
contribute to an excursion of water
quality standards, including the specific
issues and alternatives for public
comment identified througnout this
preamble. Additionally, EPA requests
public comment on any additional
options for consideration, including
new options based on consideration or
combination of factors discussed in the
preamble.
EPA intends to include a provision in
the final Guidance specifying the extent
to which permitting authorities in the
Great Lakes may consider the presence
of intake water pollutants when
establishing water quality based effluunt
limitations. EPA requests comment on
all aspects of this subject, including all
issues raised in the preamble discussion
above, and any suggested alternative
requirements or combinations of
requirements to address the subject and
issues in the final rule.
In addition, EPA invites comment on
whether any finalized requirements
addressing intake water pollutants
should bo restricted only to those
pollutants that, due to nonpoint source
contributions such as atmospheric
opposition, are present throughout the
Groat Lakes Basin at about the same
concentration which already exceeds
toe water quality criterion. The presence
of these pollutants was a primary
impetus for Hie Steering Committee's
Initial development of draft provisions
addressing intake water pollutants.
Reductions in ambient concentrations of
somo of these pollutants may be very
difficult to currently achieve. For
example, the current ambient
concentrations of PCBs may reflect moro
tho contributions of nonpoint loadings
from atmospheric deposition and
contaminated sediments than from
point sources. Removal of all sediments
containing PCBs from the Basin may not
bo practical duo to the amount of
sediments and the availability of
disposal or treatment of the sediments.
Likewise, control of all contributions of
PCBs into the air may not be
immediately possible, particularly if the
introduction of PCBs into the air occurs
outside the United States. Pollutants of
this type, due to their wide-spread
presence in the Basin, may represent the
greatest application of the Options for
addressing intake water pollutants.
f. Other Applicable Conditions.
Procedure 5.F.1 of appendix F of the
proposed Guidance states that effluent
limitations are required to comply with
other State, Tribal and Federal laws and
regulations, including technology-based
requirements and antidegradation
policies. Section 301(b) of the Clean
Water Act requires NPDES permits to
contain effluent limitations to meet both
the technology and water quality-based
requirements of the CWA. The proposed
Guidance addresses implementation
procedures for establishing appropriate
water quality-based controls and does
not provide specific direction to permit
authorities regarding implementation of
State, Tribal or Federal technology-
based requirements. In addition, State or
Tribal law or regulations may require
NPDES permits to include WQBELs
even if the reasonable potential
determination procedures in procedures
5.B.1, 5.B.2, and 5.C of appendix F
would not require a WQBEL to be
included in the permit. In these cases,
the more stringent State or Tribal
requirements may be applied pursuant
to section 510 of the Clean Water Act.
Additionally, implementation of the
antidegradation requirements of
appendix E of the proposed Guidance
may require establishment of numeric
effluent limitations in a permit in order
tn assure that further degradation of a
water body by the point source will not
occur, These limitations would be set,
not to ensure that a facility will achieve
a numeric water quality criterion, but
rather to limit increases in a facility's
effluent discharge under specified
circumstances consistent with the
antidegradation policy.
Also, procedure 5.F.2 of appendix F
provides that when the permitting
authority is determining the necessity
for WQBELs, information from
chemical-specific, whole effluent
loxicity and biological assessments must
be considered independently. EPA has
established a "Policy on the Use of
Biological Assessments and Criteria in
the Water Quality Program" (June 1991),
which is available in die administrative
record for this rulemaking. The policy
recommends that permitting authorities
fully integrate chemical specific, whole
effluent toxicity and bioassessment
approaches into their water quality-
based toxic control programs. This
policy is also discussed in the TSD at p.
22, Because each water quality
assessment method has unique as well
as overlapping attributes, sensitivities,
and program applications, EPA believes
that no single approach for detecting
impacts should be considered uniformly
superior to any other approach. For
example, the inability to detect
receiving water impacts using a
biosurvey alone is insufficient evidence
to waive or relax an effluent limitation,
established using either of the other
methods. The most protective results
from each assessment conducted should
be used in the effluent characterization
process. Similarly, the results of one
assessment technique should not be
used to contradict or overrule, the results
of the other(s). ' •
Proposed procedure 5.F-2 of appendix
F is consistent with the National policy
of independent applicability. EPA
invites comment on all aspects of this
provision including whether the policy
. of independent applicability should
apply to determinations of appropriate
effluent limitations based on either Tier
I criteria or Tier II values in the Great
Lakes System.
Finally, procedure 5.F.3 of appendix
F requires that permitting authorities
also establish a WQBEL if the discharger
has a pollutant in its effluent at
detectable levels and fish tissue from
the water body also contains the
pollutant at levels that exceed the tissue
basis of the water quality criteria. This
provision applies to instances where
proposed procedures 5.B and 5.C of
appendix F do not project the
reasonable potential of a discharger to .
cause or contribute to an excursion
above a Tier I criterion or Tier II value
but tissue data from ambient fish
sampling demonstrates an excursion.
These instances occur when ambient
water concentration monitoring either
does not include the pollutant of
concern or else the pollutant is present
in ambient waters at a level below the
ability of analytical chemical methods
to detect or quantify. Nevertheless, the
presence of the pollutant in fish tissue
at levels that exceed the tissue basis of
the Tier I criterion or Tier n value
demonstrates that the criterion or value
is not met. Under NPDES regulations at
40 CFR 122.44(d)(l){i), a WQBEL is
required for that pollutant or pollutant
parameter whenever there is
information that demonstrates that the
discharge, of a pollutant causes or
contributes to such an excursion. The
provisions of proposed procedure 5.F.3
of appendix F implements the
requirements of 40 CFR 122.44(d)(l)(i)
with respect to ambient fish tissue data.
In using fish tissue data, care should
be exercised by the permitting authority
.in determining what fish tissue data are
representative of ambient conditions.
For example, a fish must be expected to
have lived within the geographic area of
concern sufficiently long .enough to
have reached or approached steady state
conditions in terms of bioaccumulation.
Steady state occurs when the level of
pollutant uptake is approximately equal
to the level of pollutant elimination
from the fish. EPA guidance on these
considerations is provided in
"Assessing Human Health Risks from
Chemically Contaminated Fish and
Shellfish: A Guidance Manual" (USEPA
September 1989, EPA-503/8-89-002),
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Federal Register / Vol. 58, No. 72 /Friday, April 16, 1993 7 Proposed Rules
20967
which is available in the administrative
record for this rulemaking.
The proposed procedure 5.F.3 of
appendix F compares the geometric
mean of tissue samples collected from
ambient fish to the tissue basis of the
Tier I criterion and Tier II values for
human health and wildlife protection.
The tissue basis is equal to the
bioaccumulation factor that was used to
calculate the Tier I criterion'or Tier IE "
value multiplied by the Tier I criterion
:or Tier-H value. The tissue basis for the
same pollutant may differ for human
health arid wildlife criteria arid values;
if any tissue basis is exceeded, ,
reasonable potential exists with respect
to facilities discharging detectable levels
of the pollutant. .; '
The mean of the ambient data is used
in the comparison to be/consistent with
the assumptions of the criteria, that is,
wildlife-and human consumers of fish
eat an assemblage of fish. A mean best
reflects this assemblage. The geometric
mean is used as the most representative
way to reflect the average of
environmental samples. EPA invites
specific comment on what characteristic
of. ambient data (mean, average,
maximum, etc.) should be used for .
comparison to the tissue basis of Tier I
. criteria or Tier II values. EPA also
. invites comment on what type of mean,
geometric, arithmetic, harmonic, or ;
others, should.be used for this •__•
comparison.
The proposed procedure 5.F.3 of :
appendix F also recognizes that there
may be differences in tissue
concentrations between fish samples
collected from a specific water body.
The reasons for this include differences
in lipid content between fish, the ages
' offish, arid the actual exposure of
individual fish. The use of a geometric
mean in the comparison serves to
overcome some of the inherent
variability because the mean reduces the
effect of any one sample. However, there
may still be some variability associated
with using fish tissue data. Therefore,
the proposed procedure 5.F.3 of
appendix F directs the permitting . :
authority to consider the variability of a
pollutant's biocoiicentration and .
bioaceumulation in fish. The assessment
of the variability may-be accomplished
by applying specific factors to adjust for
differences in lipid content or age, or by
applying an overall factor based on
review'bf the variability in literature or
field data. Whatever method is used by
the permitting authority taiust be
described in the administrative record
supporting the permit decision. EPA
invites comment on whether 'the final
Guidance should allow permitting . ;
authorities to determine this variability
on a site-specific basis; or otherwise
include specific procedures, for :
addressing each part of the variability or
a uniform factor to address overall
variability.
The proposed procedure 5.F.3 of
appendix F applies to all facilities that
discharge detectable levels of a
pollutant into a water body where the.' .
pollutant is found in the fish tissue in
the water body at levels exceeding the
tissue basis of a Tier I criterion or Tier
n value. EPA is proposing that all
facilities that discharge detectable levels
of this pollutant into the water body are
contributing the pollutant and therefore
meet the requirements of 40 CFR
122.44(d)(l)(i). Because fish are mobile
and thereby reflect exposure'over the
entire water body, the fish tissue
concentrations reflect the accumulated
effect of all discharges. EPA invites
specific comment on this provision of
the proposal including whether the term
"wate'r body" should be defined in the
final rule; any specific factors that
should be considered in defining this
term; and whether the scope of this -
provision should be limited to the
definition of "same body of water"
discussed as part of proposed procedure
5.E of appendix F to part 132 in the
preamble above.
F. Whole Effluent Toxicity
1. Background
^ Today's preamble has focused, thus
far, on the effect of individual pollutants
on the water environment. In nature,
pollutants are often not isolated;, they
are combined in effluents, and these
effluents are, in turn, combined in
receiving waters. Because the toxic
effects of pollutants may change when
they react with other pollutants, a focus
on individual pollutants does not
provide complete protection of water
quality. Procedure 6 of appendix F of
the proposed Guidance sets forth
procedures for controlling the toxic
effect of an effluent as a whole (known
as "whole effluent toxicity" or "WET").
Concern for controlling the toxic
effects of effluents is reflected in both
the CWA and the Great Lakes Water
Quality Agreement (GLWQA). Article II
of the GLWQA and section 101(a) of the
CWA provide that the discharge of
. toxics in toxic amounts should be
prohibited. In addition, General .
Objective (d) of Article HI of the
GLWQA provides that water should be
free from materials that will produce
conditions that are toxic or harmful to
human, animal or aquatic life. Pursuant
to these goals, today's proposed
procedure seeks to ensure that
combinations of pollutants do .not cause
toxic effects.
The whole effluent approach to toxics '-•
control for the protection of aquatic life
involves the use qf acute and chronic
toxicity tests to measure the toxicity of
wastewaters. An acute test is defined as
a test of 96 hours or less in which
lethality or immobilization of aquatic
organisms is the measured endpoint. A
chronic test is defined as a long-term
test in which sublethal effects, such as ,
impaired fertilization, growth, or' • •
reproduction, are measured, in addition
to lethality or immobilization. Aquatic
organisms used hi the tests include
invertebrates, fish, and plants.
Terms commonly u§ed to express the
toxicity of ah effluent include the lethal
concentration (LC) and the no observed
effect concentration (NOEC). The LC is
the'concentration of an effluent at
which a certain percentage of test
organisms die (for example, if 50
percent of the test organisms die in 20
percent effluent, the LC50=20). The ;
NOEC is the highest concentration of
effluent that causes no ohservable . :
adverse effects in the test organisms (for
example, if none of the test organisms
exhibit any.adverse effects in 20 percent
effluent, but some organisms exhibit
adverse effects in 21 percent effluent,
the NOEG - 20). Other commonly used
terms are acute toxic units (TUa) and ,
chronic toxic units (TUC), which are
defined as follows: . •
"TUa=10Q/LC50
TUC = 1007 NOEC
For example, an effluent with LCso = '
20 translates to 5 TUa's.
2. Current National Guidance
a. Regulations. EPA regulations define'
whole effluent toxicity as the aggregate
toxic effect of an effluent measured ••
directly by a toxicity test (40 CFR
122.2). EPA's authority to set limits on;
toxicity was upheld in Natural
Resources Defense Council Inc. v. EPA,
859 F.2d 156 (D.C.Cir. 1988).
As discussed in section Vin.E of -
today's preamble, EPA's existing :
regulations require NPDES permits to
include water quality-based effluent
limitations (WQBELsj to control all
pollutants or pollutant parameters, .
including WET, that the permitting
authority determines are or may be
discharged at a level which will cause,
have the reasonable potential to cause,
or contribute to an excursion above any
water quality standards including -
numeric and narrative criteria for water
. quality (40 CFR 122.44(d)(i)); When r -
determining whether a discharge will
cause, have the reasonable potential to
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20968 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
cause, or contribute to an excursion
above a water quality standard, a
permitting authority must use relevant
available data, including facility-
specific effluent monitoring data where
available. Additionally, a permitting
authority must use procedures that
1 account for existing controls on point
and nonpoint sources of pollution;
sensitivity of aquatic organisms;
variability of the pollutant or pollutant
parameter in the effluent; and, where
appropriate, the dilution of the effluent
In tho receiving water (40 CFR
122.44{dMlHii)).
If a permitting authority determines
that a discharge causes, has the
reasonable potential to cause, or
contributes to an excursion of an
applicable numeric water quality
criterion for WET, it must include a
WQBBL for WET in the permit (40 CFR
122,44(d}{l)(iv)). In the absence of a
numeric water quality criterion for WET
fa a water quality standard, a permitting
authority must derive an appropriate •
WQBEL for WET that will insure
compliance with narrative criteria for
wat«r quality unless the permitting
authority demonstrates that chemical-
spedOc WQBELs are sufficient to attain
and maintain applicable numeric and
narrative water quality criteria (40 CFR
122,44(dJ(lKv)).
Currant NPDES regulations at 40 CFR
part 136 require permitting authorities
to use analytical methods promulgated
at 40 CFR part 136. In the case of WET,
there are no promulgated analytical
methods. When there is no analytical
method promulgated, permitting
authorities have the discretion to
specify the method for use.
b. Existing Technical Guidance. EPA
guidance on developing WQBELs for
WET is set forth in the "Technical
Support Document for Water Quality-
based Toxics Control ("TSD"}" (EPA/
505/2-90-001, March 1991), which is
available La the administrative record
for this rulernaking. Copies are also
available upon written request from the
person listed in section XIII of this
preamble. In the TSD, EPA provides
recommendations on methods for,
among other things, developing acute
and chronic WET criteria from State or
Tribal narrative water quality criteria,
determining when a discharge has the
reasonable potential to cause or
contribute to an excursion above water
quality standards, and conducting
additional studies to identify the cause
and method for treating WET. The TSD
is EPA guidance only. It does not
establish or affect legal rights or
obligations.
Currently, there are no National water
quality criteria for WET. In the TSD,
EPA recommends that a State's narrative
criterion be interpreted as 0.3 TUa and
1.0 TUC. Achievement of the criterion is
measured with acute and chronic WET
tests using at least three aquatic species.
EPA also recommends in the TSD that
the 0.3 TUa and 1.0 TUC values be
applied as 24-hour and 4-day averages
respectively, and that these values not
be exceeded more than once every three
years. These recommendations mirror
the duration and frequency assumptions
of EPA's National chemical criteria for
protection of aquatic life.
The TSD explains the derivation of
the 0.3 TUa and 1.0 TUC values. The 0.3
TUa value represents the concentration
that assures no lethality or mortality.at
any point xvithin the ambient water
column. EPA collected information on
496 acute 96-hour WET tests in the early
1980's which showed no mortality at
the 0.3 TUa level in 91 percent of the
samples and used this information to
support the recommendations in the
TSD. The 1.0 TU0 value represents the
highest concentration at which chronic
tqxicity effects are not observed
throughout a waterbody.
In the TSD, EPA recommends
applying the 0.3 TUa acute criteria value
at the edge of an acute mixing zone and
the 1.0 TU0 chronic criteria value at the
edge of a chronic mixing zone, unless
otherwise prohibited by a State's water
quality standards. (EPA interprets the
CWA to give States the discretion to
allow mixing zones in their water
quality standards.) The TSD recognizes
mat in States that prohibit mixing
zones, effluent limitations must assure
that all State;adopted numeric criteria
or interpretations of the narrative
criterion are met within the discharge
itself. -
An acute mixing zone is a zone ~
immediately surrounding a discharge
point ivhere neither acute nor chronic
criteria need be met. (Acute mixing
zones are also sometimes referred to as
zones of initial dilution (ZEDs) or areas
of initial mixing (AIMs). However, these
terms may also have different regulatory
definitions and may not be always used
to denote an acute mixing zone.) A
chronic mixing zone is where acute
criteria must be met. All chronic criteria
must be met at the edge of that zone.
The TSD guidance also recommends
that mixing zones be restricted in size
in order to prevent impairment of the
integrity of a waterbody.
The TSD guidance recognizes that
permitting authorities have flexibility in
assessing whether a discharge has
reasonable potential to exceed water
quality standards. For example, an
authority may opt to use a stochastic
dilution model that incorporates both
ambient dilution and effluent variability
rather than use a steady state dilution
model with a statistically defined
maximum effluent concentration. Also,
a permitting authority may decide to
develop a WQBEL in the absence-of
facility-specific effluent monitoring
data. Whatever approach is selected by
the authority, it must satisfy all
requirements of 40 CFR 122.44(d)(l)(ii)
summarized above.
Under EPA regulations, at least three
outcomes are possible when deciding
whether a facility causes, has the
reasonable potential to cause, or
contributes to an excursion above a
water quality criterion. First, a
permitting authority may determine that
, WET in a facility's discharge may be
discharged at a level which causes, has
the reasonable potential to cause, or
contributes to an excursion above a
narrative or numeric water quality
criterion. In this case, EPA regulations
require that the permitting authority
establish a WQBEL in the permit. (40
CFR 122.44(d)(l)(i)) This WQBEL must
be for WET, unless the permitting
authority can demonstrate that
chemical-specific limits are sufficient to
attain and maintain applicable
standards. (40 CFR 122-44(d)(l)(v))
Under EPA regulations and the TSD,
reasonable potential is shown where an
effluent, in conjunction with other point
and nonpoint sources, is projected to
cause an excursion above the water
quality criterion. This projection is
based upon an analysis of available data
that accounts for, among other things,
limited sample size and effluent
variability.
Second, a permitting authority may
have inadequate information to
determine whether a discharge causes,
has the reasonable potential to cause, or
contributes to an excursion of a water
quality criterion. In this case, EPA
regulations do not require that the •
permitting authority establish a WQBEL,
however, the TSD recommends that the
permitting authority establish
appropriate monitoring requirements
and a reopener clause in the permit (see
TSD at p. 60). A reopener clause
authorizes "reopening" the permit and
establishing additional permit
conditions based upon monitoring
results or other new factors that indicate
that the effluent may cause, hav.e the
reasonable potential to cause, or
contribute to an excursion above Water
quality standards. When permits are '
"reopened" in this manner, permitting
authorities typically impose WQBELs
for WET or require a discharger to
perform a toxicity reduction evaluation ,
(TRE).
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Federal Register / Vol. -58, No. 72 / Friday, April 16, 1993 / Proposed Rules
20969
•- Third, a permitting authority may .
determine that WET in a facility's
discharge is not discharged at a level
that causes, has the reasonable potential
to cause, or contributes to an excursion
above a water quality criterion. In this
case, EPA regulations do not require
that the permitting authority establish a.
WQBEL, however. The TSD
recommends that effluent monitoring be
.repeated at a frequency of at least once
every five years (see TSD at p, 60).
In the TSD, EPA also recognizes that
permitting authorities may need to
. require permittees to take specific
actions to identify the causes of •
exceedances of WET WQBELs. The TSD
recommends that permitting authorities
require permittees that are not in
compliance with their WET WQBEL to
;use TREs to identify the causes of WET,
isolate the sources of WET, evaluate the
effectiveness of WET control options,
and confirm the reduction of TOT. EPA
has published guidance for conducting
TREs including "Generalized
Methodology for Conducting Industrial
Toxicity Reduction Evaluations (EPA/
600/2-88/070)", "Toxicity Reduction
Evaluation Protocol for Municipal
Wastewater Treatment Plants (EPA/600/
2-88/062)", "Methods for Aquatic'
Toxicity Identification Evaluations;
Phase i Toxicity Characterization
Procedures (EPA/600/3-88/034)",
"Methods for Aquatic Toxicity
Identification Evaluations; Phase 2
Toxicity Identification Procedures
'(EPA/600/3-88/035)", and "Methods for
Aquatic Toxicity Identification
Evaluations; Phase. 3 Toxicity
Confirmation Procedures (EPA/600/3-
88/036)", which are available in the
administrative record for this
rulemakirig.
EPA's guidance in the TSD
recommends that TREs be required
whenever a discharger exceeds a WET
WQBEL and the effluent exhibits
measurable WET more than 20 percent
of the time. The recommendation in the
TSD was based on the performance
experience of EPA's research laboratory
in Duluth, Minnesota which has
successfully performed the toxicity
identification evaluation step of a TRE
on over 60 dischargers. If the discharge
exhibits WET less than 20 percent of the
time, the specific procedures of EPA's
toxicity reduction evaluation guidance
may be unable reliably to identify the
cause of toxicity.
3. Great Lakes Guidance
Procedure 6 of appendix F of the
proposed Guidance provides specific
requirements for controlling the WET of
discharges to the Great Lakes System.
The procedure contains four sections:
Discharge requirements for WET,
appropriate test methods to measure
WET, requirements for permit •" •
conditions, and reasonable potential
procedures for determining whether or
not limits for WET are necessary. The
. procedure does not cover all topics
addressed in the TSD. The proposed
Guidance on WET merely supplements,
rather than replaces, the regulations at
40 CFR 122.44(d)(l) for dischargers to
the Great Lakes System.
The requirements of procedure 6 of
appendix F apply without regard to the
cause of toxicity in an effluent.
Specifically, these requirements apply
whether or not one or more of the
pollutants listed in Table 5 of part 132
of this Guidance is the cause or possible
cause of toxicity in an effluent. As set
in more detail elsewhere in this
preamble, the.ratibnale for not applying
Implementation Procedures 1 through 5
and 7 through 9 to the Table 5 '-..'•"
pollutants relates to fundamental /
inconsistencies between.the nature of
the pollutants and the specific
requirements of the procedure,?. These
? considerations are not relevant with
respect to procedure 6, which sets forth
requirements with respect .to the toxicity
pf effluents as a whole. A contrary
viewpoint would seriously limit the
effectiveness of the WET procedure
since at least one of the Table 5
pollutants is likely to be present in the
vast majority of discharges to the Great
Lakes System.
• a. WET Basic Requirements.
Procedure 6.A of appendix F prohibits
any discharge from: exceeding 1.0 TUa
at the point of discharge; causing or
contributing to receiving water quality
exceeding 1.0 TUC (subject to certain
exceptions); and causing or contributing
to causing an excursion above any ,
numeric WET criterion Or narrative
criterion for water quality within a State
or Tribal water quality standard.
Procedure 6 does not require a Great
Lakes State or Tribe to adopt numeric
criteria for WET. The proposed Great
Lakes Guidance, rather, specifies .
effluent restrictions that apply when
either narrative or numeric criteria are
involved. Like the Federal regulations at
40 CFR 122,44(d)(l) (iv) or (v), which
provide for control of WET with either -
numeric or narrative criteria,
respectively, the proposed Great Lakes
Guidance allows- the Great Lakes States
or Tribes to choose the preferred form
of criteria to implement. The proposed
.Guidance is at least as-.stringent as the
Federal regulations.
The Technical Work Group of the
Initiative Committees considered
whether to require all Great Lakes States
or Tribes to adopt numeric criteria for
WET- This approach has the potential to
ensure the greatest consistency when,!
controlling WET, The Technical Work
Group chose not'to require the adoption-
of numeric criterion for WET due to a
regulatory difference between
implementation of numeric criteria and
implementation of narrative criteria in
existing Federal regulations. Under 40
CFR 122.44(d)(l)(v), permitting
authorities, may decide that WQBELs for
WET are not necessary if the State's
water quality standard does not contain
a numeric criterion for WET and the
permitting authority demonstrates in the
fact sheet ,or statement of basis of the "
NPDES permit that chemical-specific
limits will be sufficient to prevent ...;".
toxicity. This same discretion is not
available for States that have, a numeric
criterion for WET in their WQS. To ,
preserve this flexibility for the Great
Lakes States, the Technical Work Group
chose to structure procedure 6 in the
manner set forth in the proposed
Guidance. However, under proposed ,
procedure 6, Great Lakes States and
Tribes will be required to meet certain
specific requirements in controlling
WET whether the applicable water
quality criteria are expressed in the
narrative or numeric form. EPA believes
that, under this procedure, discharge
requirements for WET will be ' :
reasonably consistent among the Great
Lakes States and Tribes.
EPA invites comments from the
public as to whether the proposed
Guidance should require Great Lakes^
States and Tribes to adopt numeric
criteria for WET. In addition, if numeric
criteria should be adopted, EPA is
interested in receiving comments
regarding what numeric criteria,
including those specified in the TSD
(0.3 TUa and 1.0 TUc), would be
appropriate.numeric criteria for WET
i. Acute Toxicity Control. To protect
against acute (short-term) effects in
mixing zones, procedure 6.A.1 of the
proposed Great Lakes Guidance
proposes that no discharge exceed 1.0
TUa. The 1,0 TUa maximum limitation
or "cap" is by definition no more than
50 percent mortality or immobilization.
in 100 percent effluent.
The 1.0 TUa effluent cap is based
upon the proposals of the Great Lakes
Initiative Steering Committee.'The
Steering Committee believed that the 1.0
TUa cap would protect water quality
either as a single effluent limitation in
water providing substantial dilution or
in concert with a chronic WET limit in
waters without substantial dilution.
Whether a chronic limit is required to
supplement a limit of 1.0 TUa depends
upon the amount of dilution that will
occur in the receiving water. In waters
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20970 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
providing dilution of more than three
times effluent flow, a 1.0 TU, limit will
ba sufficient to attain and maintain the
WET criteria recommended in the TSD
(0.3 TUJ. (There is approximately a
three-fold difference between the 1.0
and 0.3 TU» values.) Indeed, in these
situations, there is a possibility that a
1,0 TU. may be overly stringent since,
in these situations, the actual effect of
the effluent in the receiving water, after
dilution, may be less than 0.3 TU, if the
effluent is completely mixed after
discharge. However, effluents in many
of these situations actually form plumes
and ara not completely mixed for some
distance downstream of the discharge.
Discharge plumes can overlap such that
tho toxic effects of the effluent are
compounded La the ambient water to
the degree that the toxicity overwhelms
thtt immediate aquatic life community.
In addition, calculation of the WET
concentrations at the edge of the plumes
can pose an administrative burden in
collecting the necessary dispersion
information for conducting the
calculations, For these reasons, the
consensus of the Steering Committee
was to propose an effluent cap of 1.0
TU«,
The Steering Committee recognized
that in discharge situations which
provide dilution of less than three times
tlw effluent flow, the 1.0 TU. effluent
limitation may not be stringent enough
to insure that a narrative "no lethality"
criterion, the 0,3 TU, value or other
approved numeric criterion for acute
WET would be met. The reason for this
lies in the definition ofi.O TU.as 100
times the reciprocal of the LC50. The
LC50, as previously discussed in today's
preamble, is the effluent concentration
at which 50 percent of the exposed
aquatic organisms demonstrate lethality
or immobilization. In discharge
dominated situations where the
receiving water is comprised of a
substantial fraction of the effluent, an
effluent discharged at toxicity of 1.0 TU,
may not be sufficiently diluted to
prevent lethality to organisms in the
receiving water. In these situations, the
appropriate control on toxicity should
be based on the threshold at which
ocuto toxicity occurs. The proposed
Guidance uses effluent limitations on
chronic toxicity as the means for
accomplishing this. In contrast to the
acute effluent limitation, the chronic
effluent limitation is based on meeting
a receiving water condition of 1.0 TUC
ot the edge of the mixing zone, if such
a mixing zone is allowed. The definition
of 1,0 TU£ is the lowest effluent
concentration at which no effects,
Deluding lethality or immobilization,
are observed. It is a measure of the
threshold of.incipient toxicity.
Therefore, for discharge scenarios with
small amounts of available dilution,
chronic testing should be performed and
evaluated for unacceptable acute
toxicity. When acute effects are
measured, then a chronic limit based
upon the level causing lethal effects
should be imposed in addition to or in ,
lieu of the 1.0 TU. effluent cap.
The 1.0 TUa effluent cap is consistent
with the goal of the GLWQA at Annex
10, Part 3.(a)(i), where acute
lexicological effects are prohibited. The
GLWQA defines acute toxicological
effects as whether the substance is lethal
to "one-half of the test population of
aquatic animals in 96 hours."
Depending on the test species, the acute
tests will last for either 48 hours (for
invertebrates) or up to 96 hours (for
vertebrates). Acute mixing zones would
provide the basis for toxicity greater
than 1.0 TUa, and are therefore not part
of the proposed Guidance.
EPA invites comment on the utility of
other options for preventing acute WET
effects in low dilution receiving water
situations. In specific, EPA invites
comment on the use of another acute
WET testing endpoint, such as the LCi
(effluent concentration at which 1
percent of the organisms demonstrate
lethality or immobility) or a chronic
toxicity test endpoint equivalent to 0,3
TUa, either applied directly as an
effluent limitation or as an ambient
condition applied at the edge of the
mixing zone. EPA also invites comment
on whether the final Guidance should
allow for acute mixing zones, and if so,
what should be the maximum size.
In addition, EPA invites comment on
the utility of other options for
preventing acute WET effects in high
dilution receiving water situations. In
specific, EPA invites comments on ..
whetherthe proposed'effluent cap of 1.0
TU« is too restrictive in high dilution
situations, and if so, what effluent
conditions would be fully protective of
the narrative water quality criterion. In
addition, EPA invites comment on the
utility of an ambient criterion of 0.3 TUa
applied at the edge of an acute mixing
zone for these situations, and on
appropriate methods to calculate or
estimate acute mixing zones.
EPA also invites comments on
whether it would be appropriate to
allow discharges with toxicity in excess
of 1.0 TUa where site-specific
information is available to demonstrate
that such discharges will not cause,
contribute or have the reasonable
potential to cause or contribute to an
exceedance of a State or Tribal water
quality standard.
ii. Chronic Toxicity Control. The
proposed Guidance, at procedure 6.A.2
of appendix F, requires that a value of
1.0 TUC must be maintained at all points
of the receiving water except (i) within
a mixing zone, or (ii) in any portion of
the receiving water for which a '
.. permitting authority has demonstrated
that due to the site-specific physical and
hydrological conditions, it is
unnecessary to apply any chronic WET
requirements to protect aquatic life. The
• 1.0 TUC value is, by definition, the point
at which no effect is observed in a test
solution that approximates the dilution
of the effluent in the receiving water.
This requirement is consistent with the
TSD recommendation.
EPA invites comment on the ability of
1.0 TUC applied at the edge of a chronic
mixing zone to sufficiently achieve a
State or Tribe's narrative water quality
criterion. In particular, EPA invites
comment on alternative definitions of
1.0 TUC based on the use of a different
chronic toxicity test endpoint (for
example the.IQjs endpoint). In addition
EPA invites comment on whether the
1.0 TUC criterion should be adjusted
higher or lower to reflect the sensitivity
of aquatic organisms indigenous to the
_Great Lakes System.
Under procedure 6.A.2 of appendix F
of the proposed Guidance, a Great Lakes
State need not apply the 1.0 TUC
requirement (and therefore need not
impose a chronic WET WQBEL) when a
State demonstrates that due to local
physical or hydrologic conditions of the
receiving water, it is unnecessary to
apply any chronic whole effluent
toxicity requirements to protect aquatic
life. This text is similar to that included
in procedure 1 of appendix F, which
provides that.States may develop site-
specific modifications to chronic
aquatic life criteria/values for individual
pollutants to reflect local physical or
hydrologic conditions.
As explained in section VIII. A of this
preamble, EPA believes that there may
be sites within the Great Lakes System
where, due to physical or hydrologic
conditions, aquatic life will not remain
for more than 96 hours. In such
situations, WQBELs are not necessary to
protect aquatic life from chronic
impacts. Since the physical and
hydrologic condition justification for
the exception to procedure 6.A.2 of
appendix F is functionally equivalent to
a justification for the removal of a
designated use at 40 CFR 131.10(g)(2),
(4), and (5), EPA expects this exception
will typically be used for waters where
a full aquatic life use is unattainable.
States must ensure that the application
of this exception does not impair the
water quality of downstream waters.
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20971
EfA invites comment on the ability of
this exception to provide adequate
protection of waters tributary to those
waters where the exception may apply.
In particular, EPA invites comment on, •
• the use of a 96-hour exposure psriod to
define the waters where the exception
applies and whether an alternative
definition should be uspd.
iii. Numeric and Narrative Criteria.
The proposed Guidance prohibits any
discharge from causing or contributing
to an excursion above any State or Tribe
adopted numeric criteria for WET or
interpretation of the narrative criterion
for water quality. This provision was
not contained in the Steering
Committee's proposal. EPA added
Erocedure 6.A.3 of appendix F to make
: clear that the proposed Guidance on
WET merely supplements, rather than
replaces, the requirements of 40 CFR
122.44(d)(l) for dischargers into the
Great Lakes System. EPA believes that
procedure- 6.A.3 is necessary because
there may be instances where a
Federally-approved State or Tribal water.
quality standard has additional or more
stringent requirements pertaining to
toxicity than those contained in today's
proposal. Procedure 6.A.3 makes it clear
that these additional requirements must
still be met. EPA solicits comment on
whether.or not procedure 6.A.3 of
appendix F is a necessary or appropriate
part for the proposed Guidance.
• b. WET Test Methods. Procedure 6.B.
of appendix F of the proposed Guidance
requires all WET tests be performed in
accordance with test procedures -
approved under 40 CFR part 136-.
Current NPDES regulations at 40 CFR
part 136 require permitting -authorities
to use analytical methods promulgated
at 40 CFR part 136. In the case of WET,
there are no promulgated analytical
methods. When there is no analytical
method promulgated, permitting ;
authorities have the discretion to
specify the method for use. The
proposed Guidance at procedure 6.B is
consistent with this .current NPDES
requirement. '•. •. ' '.--...
Although EPA has yet to approve any
analytical methods for WET under 40
CFR part 136. EPA expects to do so
before the proposed Great lakes Water
Quality Guidance is finalized. Until
such methods are approved, permitting
authorities have the discretion under
procedure 6.B to choose appropriate
analytical methods, '
EPA expects that permitting
authorities, in exercising this discretion,
' will require WET analytical methods
that include conditions such as the test
species to be used in tests, length of
exposure for both acute and chronic test
procedures, conditions of the effluent
and control water solution, appropriate
methods for evaluating the data, and
reporting requirements.
EPA invites comment on the WET test
methods that should be identified in the
final Great Lakes Water Quality
Guidance. In addition, EPA invites
specific comment on what factors a
permitting authority should consider in
approving any particular test, and
whether consideration of such factors
should be required in the final
Guidance. . ,
c. Permit Conditions. The proposed
Guidance proposes specific permit
requirements for each of three
situations. These are:
(l) When sufficient data demonstrate
that the reasonable potential to violate
the requirements of procedure 6.A of
appendix F exists;
- 12) When sufficient data are not
available to determine whether the
discharge has the reasonable potential to
violate the requirements of procedure
6.A; and
(3) When adequate data demonstrate
that reasonable potential to violate the
requirements of procedure 6.A does not
exist. ,
i. Data Indicates the Reasonable
Potential for WET. Procedure 6 .C.I of
appendix F requires that permitting '
authorities impose effluent limitations
for WET when sufficient effluent-
specific data demonstrate, in accordance
with, procedures 6.D.2 or D.3, that the
reasonable potential exists to violate the
requirements of procedure 6.A.
Procedure 6.C. 1. also includes three
other provisions:
. (1) Chronic WQBELs shall be
calculated based upon the dilution
calculations specified in sections C and ,
D of procedure B3 of appendix F;
.(2) A schedule of compliance
consistent with procedure 9 of appendix
F of the proposed Guidance may be
(deluded in the NPDES permit; and
(3) When regulating using a narrative
criterion for water quality, a specific
WQBEL for WET may not be necessary
.if it can be shown f and documented in
a taci sneei or statement ol basis tor a
NPDES permit) that chemical-specific
WQBELs will ensure compliance with
the requirements of procedure 6.A*
When reasonable potential exists, the
effluent limitations for acute WET will
be equal to. or less than, 1.0. TUa. The
effluent limitations .for chronic WET,
will be derived using the equation
.specified in procedure B3.C.2.a of
appendix F for lake discharges or the
Qad developed for the discharge using
the requirement in. procedure B3.D.3.a.ii
for tributary discharges. These specific
procedures from procedure B3 calculate
the .effect of dilution in establishing an
effluent limitation that achieve a
criterion at the edge of the mixing zone.
: EPA believes that these dilution
considerations that were developed to
apply to specific pollutants also apply
'to WET. EPA invites specific comment
on the use of these procedures for WET,
and if not appropriate, suggestions on
what alternative procedure should be
included in the final Guidance.
. EPA expects that the WQBELs for
WET will be compared for compliance
purposes to all species tested. EPA
invites comments on Whether it is
necessary to provide specific .
requirements to meet the most sensitive
species. ^ : •
Because some existing dischargers .'.
may not be able to meet WET limits at
the time that their permits are reissued
or modified to include new WET limits,
EPA believes that allowing some
permittees time in which to achieve
compliance may be appropriate where
allowed for in State or Tribal water
quality standards. The proposed.
Guidance requires that compliance .
schedules, however, be developed in
accordance with procedure 9 of
appendix F of the proposed Guidance.
EPA invites comment of this provision
in conjunction with the comments on.
procedures.
The provision at procedure G.C.l.d
mirrors the existing regulation at 40 CFR
122.44(d)(l)(v). As discussed earlier, •
EPA is including this provision to
eliminate any confusion about the ,
applicability of 40 CFR 122.44(d)Ci)(v)
to facilities covered by,the Guidance.
ii, Insufficient Data to Determine the
Reasonable Potential for WET. As
previously discussed in this preamble,
40 CFR 122.44(d)(l)(i) requires a
permitting authority to impose effluent
limitations whenever it finds that a
facility has the reasonable potential to
.cause or contribute to an excursion
above a State's numeric or narrative ..
water quality criterion, Procedure 6.C.2
of the proposed Guidance recognizes the
potential for a permitting authority to
have insufficient information reliably to
aetermme waether a facility causes, has
the reasonable potential to cause, or
contributes to such an excursion. In this
instance, the proposed Guidance
requires permitting authorities" to collect
sufficient information by requiring
effluent monitoring in permits.
The Technical Work Group ,
recognized the necessity to make
permitting decisions based on good
information and the preference for
facility-specific effluent monitoring data
for making these decisions. The
Technical Work Group considered
several ways in which to collect such
information, One approach is to collect
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the necessary Information as a permit
monitoring condition. In this approach,
the permitting authority would impose
specific WET monitoring requirements
that reflect the site-specific factors of the
facility. This approach allows the
permitting authority to gather
information that is representative of the
effluent condition pver a multiple-year
period, and therefore the effluent's
variability can be reasonably assessed.
In addition, this approach allows the
permitting authority to tailor the
requirements for sample collection to
the specific instances of the facility
based on the information in the permit
application, However, this approach
does delay the determination of
reasonable potential to the next permit
reissuance action which may be five
years later.
Another approach is to require
sufficient information as part of the
permit application process. In this
approach, the permitting authority
would require the facility to collect the
necessary WET monitoring information
prior to permit issuance. This approach
has the advantage in providing the
nacessary information to make
reasonable potential determinations
before the first permit reissuance.
However, there may not be sufficient
lima to collect such information prior to
permit issuance nor may the permitting
authority know of all site-specific
factors that it may need to appropriately
determine the monitoring conditions.
A third approach is for the permitting
authority to collect the necessary
information itself prior to permit
issuance. This approach has the same
advantages and disadvantages as
requiring facilities to submit WET
monitoring information with the permit
application. It also has the additional
disadvantage of imposing a large
resource burden on States due to the
need to send inspectors to each facility
to collect the information.
Tho Technical Work Groupproposed
the alternative of requiring effluent
monitoring as a permit condition. This
proposal is also consistent with EPA's
guidance (TSD at page 60). The
proposed Guidance does not identify
the type of fedlity required to collect
this information, nor the amount and
type of effluent monitoring data that
would comprise a sufficient set of
information. The proposed Guidance
reserves the existing discretion of
permitting authorities to make these
decisions based on the site-specific
characteristics of the facility and its
receiving water. In deciding what
facilities are required to collect effluent
V4IET monitoring data, permitting
authorities may consider a number of
factors including the type of facility, the
potential sources of toxic contaminants,
the presence of individual toxic
pollutants in the effluent, and known
impacts on the receiving water In
deciding the type of monitoring that
comprises a sufficient data set, EPA
expects permitting authorities to require
WET tests using multiple aquatic
species to be consistent with the
provision of 40 CFR 122.44(d)(lKii) that
requires consideratioh.of aquatic species
sensitivity. The amount of information
is left entirely to the discretion of the
permitting authority; the means to
account for the uncertainties posed by
infrequent monitoring are addressed in
the discussion of procedure 6.D of
appendix F of part 132 in today's
preamble.
Recognizing that the approach of
collecting effluent monitoring data as a
permit condition could delay effluent
controls necessary to achieve State
numeric and narrative water quality
criteria, the Technical Work Group also
proposed that such effluent monitoring
be combined with a permit requirement
that the permittee initiate a TRE if the
monitoring demonstrated the reasonable
potential. The effluent conditions
necessary to initiate a TRE are not
specified in the proposed Guidance;
again, permitting authorities retain the
discretion to make these decisions based
on the site-specific characteristics of the
facility and its receiving water.
EPA invites comment on this,
proposed approach, and/or whether any
alternatives should be included in the
final Guidance. In particular, EPA
invites comment on whether the final
Guidance should require specific
monitoring conditions such as the
minimum number of samples to be
collected, the type of WET tests (acute
or chronic, and which species), and
which facilities need effluent WET
monitoring as a permit condition. EPA
also invites comment on whether a TRE
should be required as a permit
condition if the effluent monitoring
demonstrates reasonable potential, and
whether the final Guidance should
include a specific condition that
requires initiation of a TRE. EPA would
also like comment on whether
procedure 6 of appendix F should
require a specific reopener clause for
WET as opposed to or in addition to the
TRE requirement mentioned above.
iii. Data Indicates No Reasonable
Potential for WET. Procedure 6.C.3 of
appehdix F restates the current
authority for a permitting authority to
establish monitoring requirements for
WET in an NPDES permit. The
permitting authority may decide that it
is appropriate to impose continued
testing conditions upon those
dischargers for which it does not find
the reasonable potential to exceed
numeric or narrative water quality
criteria. Where the permitting authority
concludes that a continued monitoring
requirement is warranted based upon
the particular circumstances of a '
discharge, the permitting authority may
require continued testing for a,
reasonable period of time and then
evaluate the monitoring results at the
conclusion of this period. For example,
a permitting authority may decide to
impose continued monitoring for a
discharger for which available effluent
WET data are limited or for which more
recent information raises the specter of
reasonable potential. Under sections 308
and 402 of the CWA, a permitting
authority can require NPDES permittees
to provide WET testing data to assure
compliance with State or Tribal water
quality standards.
d. Reasonable Potential
Determinations. The proposed Guidance
specifies how a permitting authority
shall determine the reasonable potential
to exceed the condition of procedure
6.A of appendix F. These specific
procedures are similar to those of
procedure 5 of the proposed Guidance
which pertains only to individual
pollutants.
The proposed Guidance requires that
the factors described in 40 CFR
I22.44(d)(a)(ii) be evaluated when
making a determination whether
.reasonable potential to violate
procedure 6.A of appendix F exists.
These factors need to be considered in
all evaluations because the conditions of
40 CFR 122.44(d) require that when the
reasonable potential to exceed State
water quality standards exists, a limit
must be imposed into a permit. The
conditions for evaluating reasonable
potential are not limited to situations
where effluent-specific data are
available. The regulatory factors which
apply to WET and need to be evaluated
are: accounting for existing controls on
the point and nonpoint sources of
pollution, the variability of the pollutant
parameter in' the effluent, the sensitivity
of the species to toxicity testing and
where appropriate the dilution of the
effluent in the receiving water.
The first factor in 40 CFR
122.44(d)(l)(ii) requires that existing
controls on point and nonpoint sources
must be evaluated. States must ensure
that existing controls on adjacent
discharges and the discharge of interest, .
as a whole, maintain the in-stream water
quality requirements for acute and
chronic WET. If the total controls
cannot ensure that the WET
requirements will be attained and
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20973
maintained, then additional controls
need to be required in one or all cases.
Existing State procedures also need to
be used to account for multiple
dischargers or toxicity from upstream
source?.
Procedure 6 applies for the most part
when facility-specific effluent data are
available. However, there are situations
when a permitting authority may
determine without facility-specific
effluent data that the reasonable
potential to cause an excursion of a
WET criterion or the narrative criterion
exists. Effluent data from similar
industrial operations can be.used to
evaluate a facility for which no effluent-
specific data exist. This information,
within the judgement of the permitting
authority can be used as a;ba"sis for
.evaluating whether the reasonable
• potential to violate the WET
requirements exists. , ;
When effluent data are available,
procedures 6.D.1, D.2 and D.3 of
appendix F also apply. It is believed
that the procedures set forth in
procedures 6.D.1, D.2 and D.3
incorporate most of those.factors to
some extent. There may be some
situations, however, where those ,
formulas, themselves, do not involve all
of the evaluating factors from 40 CFR
122.44(d)(l)(ii). In those situations, the •••
additional factors must be considered.
i. Characterizing Acute and Chronic
Toxicity Values. Great Lakes Guidance
for-determining the reasonable potential
to cause or contribute to a violation of
State water quality standards for toxicity
is provided in procedure 6.D or
appendix F. (The Great Lakes Guidance
for assessing reasonable potential to
cause or contribute to water quality
standards violations of chemical-
specific numeric criteria is included in
procedure 5 of appendix F, which was
discussed in section VIII.E. of this
preamble.) Procedure 6.D.1 provides
jguidance for three areas: how to
characterize effluents when1 more than
one toxicity result is available for a
given time period; how to evaluate
toxicity results for different test Species;
and how to predict either chronic or
acute toxicity levels if only one of the
types of toxicity results are available. ',:/
If several acute tests are performed oh
an effluent discharged on a given day or
several chronic tests are performed.
during a given month, procedures
6.D.l.a and l.b recognize that averaging
the data for the same species is
appropriate. When only one WET test
sample is collected, it is generally
considered representative.and the most
toxic result for each species is used.to
determine if an effluent causes, has the
reasonable.potentiai to cause or;. -
contributes to a violation of the - ,' •
requirements in procedure 6.A.
However, due to the possibility that
multiple tests may be conducted during
the same day for acute tests or the same
month for chronic tests, the proposed
Guidance provides additional guidance.
Acute test results generally equate to
one day maxima, and therefore the. " . • -
proposed;Great Lakes Guidance, • :
proposes that all acute tests for the same
species collected during one contiguous
24-hour period will be averaged to give
one daily result. Similarly, since
"chronic test results in the existing Great
Lakes State NPDES programs generally
equate to monthly average:
concentrations, all chronic tests taken
during the same calendar month for the
same species will be averaged to give
one 'monthly result. The acute and
chronic averages will be used in the
comparison provided in procedure 6.D.2
and procedure 6.D.3, respectively, to
determine the need for-a limit.
The regulations at 40 CFR
122.44(d)(l)(ii) require that.species
sensitivity be taken into account when
determining whether the reasonable.
potential to exceed water quality
standards" exist. Species sensitivity
occurs because aquatic species react
differently to the causes of the toxicity ,
in an effluent. In order to address this
potential for variation and to be
consistent with the regulatory
requirements, the proposed Guidance at
procedures 6.D.l.a and l.b of appendix
F provides explicit direction to average
only test results which are for the same ,
test species. If the results from a
sensitive species were averaged with a
less sensitive species, the average would
mask the worse case toxicity levels for
the most sensitive species. The
"average'' results for each species along
with other available effluent data will be
used in the reasonable potential
determinations provided in procedures
6.D.2orD.3.
The provision in paragraph D. 1 ,c of
procedure 6 of appendix F provides the
guidance for a State or Tribe to predict
chronic toxicity from acute toxicity
results or acute toxicity from chronic
toxicity results, if one of the types of •
toxicity test results are not available.. It
is not unusual to have only one type of
test, i.e. either acute WET tests or
chronic WET tests, for a particular
effluent. The acute-to-chronic ratio
(ACR) expresses the relationship
between the concentration of WET, or a
toxicant causing acute toxicity to a
species, and the concentration of WET;
or a toxicant causing chronic toxicity to
the same species. An ACR is commonly
used to extrapolate to a chronic toxicity
concentration using exposure »
considerations and available acute
toxicity data when chronic toxicity data
for the effluent are not available. This is
often used in order to reduce testing:
costs. The AGR is ideally calculated
using effluent-specific acute and
chronic test results. In the absence of
data to develop a facility-specific ACR,
the TSD suggests that .an ACR of 10 is
an appropriate default, The default ACR
is the upper 90th percentile of all the
ACR data presented in appendix A-3 of
the TSD. Given the protective margin of
safety inherent with the use of a critical
. flow for the calculation of a chronic
: receiving water concentration, an ACR
:of 10 should provide ample protection
against chronic instream impacts.
•„ The proposed Guidance states that
effluent-specific ACRs shall be used
where available. Gathering enough data
to develop an effluent-specific ACR can
be costly and may be unnecessary to
characterize an effluent. The proposed
Great Lakes Guidance, consistent with
National guidance, allows the use'of
effluent specific ACRs, and in the.,
absence of effluent specific ACR, the use
of a default AGR of 10. EPA invites
comments on whether other values
above or below 10 would be more
suitable for default ACRs. EPA would be
interested in receiving comment oil the '
alternative numbers and the justification
for those alternative ACRs.
ii. Specific Conditions for Acute
Toxicity. The Great Lakes Guidance for
WET also contains specific ... , • -
requirements for determining the
reasonable potential to exceed the
conditions of procedure 6.A of appendix
F when effluent data are available.
Procedure 6.D contains the reasonable
potential requirements for WET which :
are equivalent to procedure 5 for - -.
chemical-specific criteria. Procedures
6.D.2 and D.3 provide customized
requirements for determining the ' '
reasonable potential to violate the WET
requirements in procedure 6.A for acute
and chronic WET effects, respectively.;
Specifically for acute toxicity, ' : '
reasonable potential exists if the results
from an acute WET test divided into 50 ;
percent is less than a factor that ',...':
accounts for effluent variability and the
number of effluent samples collected. -
These factors were calculated using a
95 percent confidence level and a 95 \
percent probability basis. The factor is
, applied to account for uncertainties-and
variability with the effluent data. As ^;.
mentioned above, this is a function of
the number of samples and the •
coefficient of variation of the effluent '
• samples. Because of the Uncertainty in:- . "
deriving a CV for data sets with less •
than 10 data points, the GV is assumed
to be Oi6. For data sets with 10 of,greater
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Federal Register / Vol. 58, No,. 72 / Friday, April 16, 1993 / Proposed Rules
samples, the CV shall be calculated by
determining tho standard deviation of
the values and dividing by the mean.
The term "individual WET tests"
means any results of acute WET tests
derived from samples taken on a
particular day when no other test results
are available) for the same day, and the
average of results, derived in accordance
with procedure G.D.l.a, when more than
ono sample was taken on a particular
day, The samples used in averaging
results for a day, would not be
accounted for in the number of samples
for determining the CV. For example, a
permittee may have eight acute test
results of samples taken on 8 separate
days. In addition, a sample was split
between the permittee and EPA during
an inspection on another day. Assuming
that both results of the split sample
meet the appropriate quality assurance
goals, both shall be averaged and the
results treated as one sample and one
result, in accordance with the guidance
at procedure 6.D.I.Q. In order to
determine whether effluent has the
reasonable potential according to
procedure 8.D.2, the CV would be based
upon a sample of 9 results and not 10
results.
Tha equation at procedure 6.D.2
provides a concise formula with which
to determine whether the reasonable
potential exists to violate the 1.0 TU.
effluent cap and therefore violate any
narrative criterion for water quality or
numeric criterion for acute WET. The
equation is based upon the discussion
provided in tha TSD for determining
wh«thor reasonable potential exists.
This equation and the premise in the
TSD is to statistically estimate the
greatest level of WET that could exist in
a particular effluent, A statistically
derived factor is applied to the highest
WET love! based upon actual effluent
data. The resultant would then be the
estimate of the highest possible level of
acute WET that could be reasonably
oxpoctod in the effluent.
This procsdf.'e is consistent with that
specified inprocedura 5 of the proposed
Guidance, The preamble discussion at
section VflI,E.2!b.i provides a thorough
explanation of the justification for this
statistical approach used in both
procedures. The equation has been
modified for acute toxicity, to relate to
tho TSD recommendations with the
basic policy of the Steering Committee
of no acute mixing zones beyond 1.0
TU,, tho criterion will equal 50 percent
without accounting for additional
receiving water flow. The expression of
tho process has been placed in equation
format for tho proposed Great Lakes
Guidance,
Comments on the basic statistical ,
approach should address the discussion
provided in the preamble discussion for
procedure 5 of appendix F. EPA invites
comments, however, regarding whether
the application of this reasonable
potential procedure is appropriate for
acute WET.
iii: Specific Conditions for Chronic ,,..,.
Toxicity. The reasonable potential
determination for chronic toxicity is
similar to the discussion for acute
toxicity. The proposed Great Lakes
Guidance formula for determining
whether reasonable potential to exceed
the 1.0 TUC requirement is that
reasonable potential exists if the level of
chronic toxicity of the effluent is greater
than the reciprocal of the product of a
multiply factor and the receiving water
concentration (RWC) of the effluent
Again, the size of the data sets dictates
the CV that is used in selecting the
multiplying factor. In addition, the
dilution flow from the receiving water is
taken into account. The dilution flow is
calculated using the guidance from
procedure B3.C for lake dischargers and
procedure B3.D for tributary
dischargers.
The proposed Great Lakes Guidance
provides additional requirements when
deriving the appropriate amount of
dilution which should be used in
developing the RWC. The RWC is based
upon the dilution of the effluent in the
receiving water. For tributary
discharges, the RWC is calculated
differently if the entity uses the,
receiving water for any portion of its
process wastewater. For entities which
do not use the receiving water for the
source water, the RWC is the source
flow divided by the sum of the Qad
derived using procedure B3 of appendix
F plus the effluent flow. For entities
which use the receiving water for some
or all of its source water, the RWC is
derived by dividing the effluent flow by
the Qad. The RWC for lake discharges is
the effluent flow divided by 11.
When the RWC is high and the
coefficient of variation is great, the
formula will calculate chronic effluent
levels that cannot be measured. For the
situations where B is greater than I/ .
RWC, the proposed Great Lakes
Guidance provides flexibility for the
State to review the raw chronic toxicity
results to determine whether or not the
discharge has the reasonable potential to
exceed the 1.0 TUC level.
This formula is consistent with the
guidance provided in the TSD, section
3. The proposed Great Lakes Guidance
recommends estimating an upper bound
of the amount of toxicity which, would
be allowed in the receiving water based
up on the available dilution. If the .
chronic test results exceed the upper
bound estimate of what can be
discharged, then the effluent has the'
reasonable potential to cause an
excursion above the numeric chronic
WET requirement. . .
EPA invites comments on whether
this approach is appropriate for
determining the reasonable potential to
exceed the chronic WET requirements
of procedure 6. A of appendix F.
e. State and Tribal Adoption of
Guidance. Section 132.4(a)(7) of the
proposed Guidance requires Great Lakes
States and Tribes to adopt procedures
that are consistent with the proposed
Great Lakes Water Quality Guidance.
Great Lakes States and Tribes shall
adopt procedures for deriving permit
limits to control WET that are consistent
with procedure 6 of the Implementation
Procedures of appendix F of the
proposed Guidance. Procedure 6 of the
proposed Guidance is intended to
implement both narrative and numeric
criteria for toxicity. In the event a Great
Lakes State or Tribe choosesjo regulate
WET through narrative water quality
criteria, those criteria may not be
implemented in any manner less
stringent than specified in the proposed
procedure. In the event a Great Lakes
State or Tribe chooses to regulate WET
through numeric water quality criteria,
those numeric criteria must be
sufficiently stringent to provide a basis
for requiring all dischargers to comply
with the terms of procedure 6. A of
appendix F.
In addition, a Great Lakes State or
Tribe must adopt procedures that, at a
minimum, require -consideration of the
same types of information as specified
in the proposed procedure 6.D of
appendix F and reach a decision that an
effluent limit is necessary where the
proposed procedures 6.D.2 and D.3
require effluent limitations.
G. Loading Limits
1. Expression of WQBELs as
Concentration and Mass Loading Rates
In the proposed Guidance, EPA is
proposing to require that water quality-
based effluent limits (WQBELs) for all
pollutants discharged to the Great Lakes
System be limited in NPDES permits in
terms of concentration and mass loading
rate, except for those which cannot
appropriately be expressed in terms of
mass. These requirements are intended
to clarify what EPA believes to be the
appropriate application of the existing
Federal regulations at 40 CFR 122.45(f)
to the Great Lakes System to most
effectively implement the objectives of
the Clean Water Act and GLWQA,
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Federal Register / Vol. 58, No. 72 / Friday,"April' 16, 1903 / Proposed Rules
20975
' ,The unique character of the Great
Lakes System is the basis for the
proposed requirement that WQBELs be
expressed in terms of both
concentration and mass loading rates.
Because of the long retention time and
the complex flow patterns of the water ,
in the Great Lakes System, the Lakes
tend to act as a sink, accumulating
persistent pollutants discharged to
them. Many of the lingering ,
contamination problems in the Great
Lakes System are the result of the long-
term build-up and slow elimination rate
of persistent contaminants in the , ....-
System, These characteristics are .
discussed in Background sections LA
and ID of the preamble. During
deliberations on the proposed Guidance,
the Great Lakes States proposed
inclusion of a provision requiring the "
expression of WQBELs as both
concentration and mass loading rate •
values to protect the integrity of the
Great Lakes System. In particular,
concerns werje expressed that increased
loads of pollutants, which might comply
with concentration limits, could
accumulate in the Great Lakes System
and result in increased difficulty in : •.
attaining the goals and objectives of the
Clean Water Act, the GLWQA and the
Great Lakes Governors' Toxics-
Agreement. The Great Lakes States were
concerned that any additional '
accumulation of these chemicals in the
Great Lakes System could prevent the
attainment of beneficial uses*
EPA shares these concerns and
believes that the use of niass loading
- rate limitations is appropriate to '
implement the general purpose of the
GLWQA to restore and maintain the '
chemical, physical and biological .
integrity of the waters of the Great Lakes
Basin Ecosystem. In order to achieve .
this purpose, the Governments of the
United States and Canada agreed, in the
GLWQA to establish programs to
eliminate and reduce to the maximum
extent practicable the discharge of
pollutants into the Great Lakes System.
(Article H). The Governments also
agreed that, consistent with these
provisions of the GLWQA, it is the •
policy of the United States and Canada
that "the discharge of toxic substances
in toxic amounts be prohibited and the
discharge of any or all persistent toxic
substances be virtually eliminated."
(Article n(a)). Additionally, the United
States and Canada agreed that all
reasonable and practicable measures
must be taken to maintain and improve
the existing water quality in those areas
of the boundary waters of the Great
Lakes System where such water quality
is better than that prescribed by Specific
Objectives and.in those areas having
outstanding natural resource value. .
(Article IV(c)). The proposed
requirement to establish both
concentration and mass-based WQBELs
in permits for discharges of pollutants to
the Great Lakes System will help to
assure progress toward these goals and
objectives.- :
The existing Federal regulations at 40
CFR 122.45(f) require, with several :
limited exceptions, the establishment .of
mass loading limitations in NPDES
permits. The following discussion
compares the requirements in the
proposed Guidance to the existing
regulation, with emphasis on the .
exceptions" in the existing regulation.
First, the proposed Guidance provides
one exception from the requirement to
express WQBELs in both concentration
values and mass loading rates. •
Consistent with the existing Federal •
regulations at 40 CFR 122.45(0(1), the
,proposed Guidance does not require
Great Lakes States to express WQBELs
as mass loading rates for pollutants
which cannot be appropriately
expressed in terms of mass, such as pH,
color, temperature, or radiation.
Second, the Federal regulation also
includes an exception to the
requirement for the development of
mass-based WQBELs for pollutants for
which technology-based limits, •
developed on a case-by-case basis using
40 CFR 125.3, cannot feasibly be
expressed in terms of mass. Because the
proposed Guidance does not apply to
technology-based limits, it.does'not
affect the application of this provision
of the Federal regulations.
Third, the proposed Guidance does
not include the exception from mass
limits in 40 CFR 122.45(f) for pollutants
for which applicable standards or
limitations are expressed in terms of ''•
other units of measurement Based on
this exceptioni permitting authorities
are not currently required to establish
mass loading rate WQBELs in all NPDES
permits if, for example,.the applicable
water quality standards are expressed
only in terms of concentration in the
ambient water. Although 40 CFR
122.45(f) does not require establishment
of mass loading limits in all permits
under these circumstances, the
permitting authority must, hpwever,
currently include any limits determined
necessary based on best professional
judgment to meet water quality
standards, including, where
appropriate, mass loading rate limits.
(CWA sec, 301(b)(l)(c); 40 CFR
122.44(d).)
The proposed Guidance is consistent
with existing EPA guidance supporting
the use of mass loading rate limitations
to protect water quality under these
circumstances. The March 1991 revised
"Technical Support Document for Water
Quality-based Toxics Control (TSD)" '
which is available in the administrative
record for this proposed rulemaking,
provides EPA's current nationwide
guidance oh the implementation of the
statutory requirements of section
301(b)(l)(C) of the Clean Water Act and
the associated Federal regulations;
specifically 40 CFR 122.44(d)(l). Copies ;
of this document are also available upon
written request from the person listed in
section XHI of this preamble. The TSD
explicitly addresses the expression of
WQBELs in terms of mass loading rates.
Section 5;7.1 of tKe TSD clarifies that
'mass loading rate limitations are,
especially important for the control of
.bioconceiitratable pollutants or those
pollutants with effluent concentrations
that are below detection levels. It further
supports the. complementary, use of
concentration limits and mass limits;
particularly in low dilution situations.
(See also 49 FR 38031, September 26, '.
1984, "Permit writers are encouraged to
express limits in terms of both mass and
concentration. Mass-based limits are
necessary and encouraged to prevent the
use of dilution as a mean's of treatment
and also,-where water quality is
limiting, control total loadings in regard
to the assimilative capacity of the . •••••'
receiving water body.")
Finally, the proposed Guidance to
express WQBELs as both.conceittration
values and mass loading rates is . .•
necessary to implement the proposed
antidegradationpolicy for the Great
Lakes System. The use of mass limits in
the Great Lakes antidegradation analysis
is discusse'd in appendix E of the •
proposed Guidance.
For the reasons identified above, EPA
believes that WQBELs for discharges.to
the Great Lakes System should be . '•
established as both a concentration
value and an equivalent mass loading
rate. EPA requests comment on all
aspects of procedure 7 of appendix F of
part 132 including whether the ,
requirement to establish WQBELs as
both concentration values and mass •
loading rates should be limited to an
identified class of pollutants, (e.g.,
persistent or bioaccumulatiye .
pollutants) and identification of any
alternative provisions to achieve the
goals of-the CWA, GLWQA, and the
Great Lakes Governors'Toxics
Agreement.
2. Procedures to Calculate Mass Loading
Limits
Proposed procedure 7 of appendix F •
establishes procedures to calculate mass
loading rate effluent limitations to "
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20976 Federal Register / Vol. 58, No. 72 / Friday, April-16, 1993 / Proposed Rules
restrict the loadings of pollutants to the
Great Lakes System. As discussed
above, procedure 7 requires that when
a WQBEL is developed based on
procedures 3,5, or other State
procedures, the limitation must be
expressed in terms of both
concentration and mass loading rate.
Proposed procedure 7 also requires
that the concentration and mass
limitations must be consistent in terms
of daily, weekly, and monthly averages,
or in other appropriate time-related
terms, (procedure 7.A). For example,
where a concantration-based WQBEL is
expressed in terms of maximum daily
and average monthly limitations, the
corresponding mass loading rate
limitations must likewise be expressed
as maximum daily and average monthly
limitations, The existing Federal
regulation at 40 CFR 122.45(d) requires
that limitations for continuous
discharges be expressed, unless
Impracticable, as average weekly and
average monthly limitations for POTWs
and maximum daily and average
monthly limitations for all other
continuous discharges. The proposed
Guidance does not change these existing
requirements, but instead ensures-
consistency between mass and
concentration-based limitations in
individual NPDES permits.
During the Initiative Committee's
deliberations on the proposed Guidance,
an alternative was considered regarding
tha use of averaging periods for
WQBELs that are based on the criterion
that U» limits wera derived to protect.
Under such an alternative, WQBELs
would bo expressed hi term,s which are
consistent with the duration of the
criterion/value upon which the
Emitatlons were based. For example,
WQBELs based upon acute aquatic life
criteria would be expressed only as
daily maxima. Similarly, it would be
acceptable under such an approach to
express WQBELs based on human
health criteria as only annual averages
because the human health criteria are
derived using long-term exposure
assumptions. This approach, however,
appears is inconsistent with the existing
NPDES regulations for continuous
discharges at 40 GFR 122.45(d). The
existing regulation allows deviations
from the standard application of daily
maxima or weekly averages, and
monthly averages only in cases where
deriving such limitations is
impracticable. EPA's guidance provided
in the TSD provides the mechanism hi
most circumstances to derive daily
maximum, weekly average, and monthly
average limitations, regardless of the
criterion, as is required by the existing
regulation. EPA welcomes comment on
all aspects of procedure 7. A of appendix
F, including the identified alternative,
other alternatives, and the practicability
of implementing the proposed
approach. EPA also requests comment
on whether only requiring that mass
loading limitations be expressed as
monthly averages, in combination with
the appropriate concentration limits
which would still be required to fully
implement 40 CFR 122.45(d), would
adequately implement the objectives of
the CWA and GLWQA for the Great
Lakes System. As discussed below with .
regard to wet-weather discharges, such
an approach may be appropriate to
address short-term effluent mass
discharge variability that may be
associated with wet weather.
Proposed procedure 7.B of appendix F
directs the permit writer to use effluent
flow rates when developing the mass :
loading rate limits that are consistent "
with those used in procedures 3, 5, or
other State procedures, to develop the
concentration-based WQBELs. For
example, under procedure 3 of
appendix F, ,a specific effluent flow rate
and a receiving water flow rate will be
utilized for each pollutant to determine •
the TMDL and WLA, and from them the
WQBEL, that will protect the water
quality standards (WQS) in the
receiving water. Under the requirements
of- procedure 7.B, an effluent flow rate
that is consistent with that used in the
foregoing process to derive a
concentration-based WQBEL for a
pollutant would be applied to derive the
mass loading rate limitation. The
existing Federal regulations at 40 CFR
a22.44(d)(l)(vii){B) and 123.25(a)(15)
require that water quality-based effluent
limits in State and Federal NPDES
permits be"* * * consistent with the
assumptions and requirements of any
available wasteload allocation for the
discharge * * *". By specifying this
requirement in today's proposal, EPA
believes that it will eliminate confusion
that might arise regarding the proper
effluent flow rate to be used in
development of mass loading rate
permit limitations and thereby ensure
greater consistency between WQBELs in
the Great Lakes System.
During the deliberation process on the
proposed Guidance, EPA and the Great
Lakes States considered requiring
permitting authorities to use design
flows for POTWs and annual average
flows for industrial facilities in all
circumstances to calculate mass loading
limitations as an alternative to proposed
procedure 7.B. These flows are used as
default values by some Great Lakes
States in establishing WQBELs and may
have the beneficial effect of providing a
consistent requirement applicable to 'all
WQBELs in a permit, rather than
requiring the development of differing
effluent flow rates to correspond to
different criteria. EPA is not proposing
this alternative in the proposed
Guidance, because EPA believes that it
is more appropriate to ensure that the
permitting authority retains the •
flexibility in establishing effluent flow
rates to adequately account for effluent
variability. EPA welcomes comment on
all aspects of procedure 7.B, including
the identified alternative or other
alternative procedures.
3. Special Provisions Applicable to Wet-
weather Discharges
During Technical Work Group
deliberations on the proposed Guidance
EPA and the Great Ldkes States
considered including specific
provisions in the loading limits
procedure to address elevated effluent
flo'ws from continuous discharges that
might occur during wet-weather
discharge events, EPA is not proposing
such text in the proposed Guidance
because it believes that the procedures
for development Of TMDLs and WLAs,
and from them WQBELs; already
provide the permitting authority with
the ability to adequately account for
effluent variability in continuous
discharges, including that resulting from
wet-weather events. EPA invites ,
comment on this conclusion and on the
provisions discussed below, which were
considered by the Technical Work
Group.
During Technical Work Group
deliberations on the proposed Guidance,
concerns were expressed regarding the
increased discharge flow rates that
might be associated with wet weather,
and.their effept.on compliance with
mass-loading rate limitations.
Specifically, it was argued that if wetr
weather events increase the flow rates
from certain point source discharges,
the potential to exceed mass loading
rate limits may also increase if the wet-
weather.portion of the discharge carries
any of the limited pollutants. In
contrast, it was argued that wet weather
will generally not pose a similar
concern for compliance with
concentration limits, as the wet-weather
component of a discharge will typically
be dilute even when it may be
contaminated with the limited
pollutant. Furthermore, the effect of the
wet-weather discharges on the receiving
water may be more complicated as
nonpoint contributions may increase
and the resulting ambient pollutant
concentrations may increase or
decrease. The effect'of wet weather on
compliance with WQS is discussed '
more;thoroughly elsewhere in the
-------
proposed Guidance. To account for the
perceived uncertain effect on water
quality of increased wet-weather mass
loading rates and potential for permit
limit violations, the Technical Work
Group considered a procedure that
would have allowed the permitting
authority, to establish special permit
conditions associated with wet-weather
mass loading rates for non-BGe
pollutants as long as such loading rates
would still result in the attainment of
the applicable water quality criteria.
The provision would have been limited
to,non-BCC pollutants because of the
overriding concerns, discussed above,
associated with long-term mass loadings
of BCC pollutants,
EPA is not proposing to include
specific provisions in the loading limits
procedure to address wet-weather flows,
because it believes that effluent
variability, which such a provision
Would seek to address, may already be
adequately addressed on a case-byrcase
basis by the permitting authority.
Effluent variability is already a required
.consideration^ determining if
WQBELs are necessary to protect water
quality (40 CFR 122.44(d)(l)(ii)), and
EPA's TSD provides EPA's guidance on
how effluent variability should be
addressed in WQBEL development.
Permitting authorities continue to have -
the ability to account for effluent
variability, even though the.proposed
Guidance on loading limits provides no
specific provisions for addressing wet-
weather, flows. Furthermore, EPA is not
aware of information showing that the
risk of violating mass limitations as a
result of wet-weather flows is actually
significant and cannot be adequately
addressed by accounting for effluent -
variability. ,
EPA requests comment on the
approach to the development of mass
, loading rate limits to account for wet-
weather effluent variability supported
by the proposed Guidance and also
solicits information on the effect of wet-
weather pollutant contributions on the
ability of permittees to comply with
mass loading limitations. EPA also
requests comment on the alternative
identified and any other methods to
appropriately account for wet-weather
induced effluent variability in the
.development of WQBELs. Finally, EPA
invites comments regarding whether it
may be appropriate to only require
monthly average mass loading WQBELs,
as discussed above in conjunction with
/procedure .7. A of appendix F, as a
mechanism to address wekweather
effluent variability ,
20977
H. WQBELs Below the Level of
Quantification
Many GreatLakes Water Quality
Initiative (GLJVQ!) pollutants cause
unacceptable toxic effects in amounts
lower than can be reliably measured by
the most sensitive current analytical
techniques. Accordingly ,-the calculated
water quality-based effluent limitations
(WQBEL) for; those pollutants are often
below a level that is analytically
quantifiable.:^Vhen the W@BEL is
calculated to be lower than a level that
can be quantified, it is difficult to
determine whether or not the facility is
complying with the WQBEL. In these
circumstances special techniques may
be necessary to assess and assure
compliance.
1, Existing National Guidance
NPDES regulations do not require
specific procedures when WQBELs are
less than quantification. However,
several EPA guidance documents have
addressed this issue. First, EPA's "Final
Guidance on Section 304(1) Listing and
Permitting of Pulp and Paper Mills" was
released on March 15,1989 (March IS,
, 1989 Guidance), which is available in
the administrative record for this
rulemaking. This document
recommends that where WQBELs are
less than the detection level for the ;
specified analytical method, the WQBEL
should be included in the permit and
.. the quantification level of the analytical
method should be the threshold for
compliance determinations. This same
issue was discussed in EPA's "Strategy
for the Regulation of Discharges of
PHDDs and PHDFs from Pulp and Paper
Mills to Waters of the United States,"
dated May'21, 1990 ("May 21,1990
Strategy"), which is available in the • '
administrative record for this :'
rulemaking. The May 21,1990 Strategy
modified the March 15,1989 Guidance
by recommending that the permit writer
specify the minimum level (ML) as the
compliance evaluation level in permits
that limit dioxin.
Finally, in March 1991, EPA
published the Technical Support
Document for Water Quality-based
Toxics Control ("TSD"),' which further
expanded guidance on this subject. This
document is-available in the
administrative record for this
rulemaking. Copies are also available -.
upon written request from the address
justed at the beginning of this preamble.
The TSD recommends applying the
concepts contained in the May 21,1990
Strategy to all pollutants.
NPDES regulations do specify how
samples are averaged to obtain a
monthly or weekly discharge limit.
- According to 40 CFR 122.2, average
monthly (weekly) discharge limit means
the highest allowable average of daily
discharges over a calendar month
(week), calculated as the sum of all
daily discharges measured during a
calendar month (week) divided by the
; number of daily discharges measured
during that month (week). All samples
taken must be included in these
averages. , :'..• ,.-.-•-
2, Great Lakes Guidance
The Great Lakes proposaTestablishes
' P™£^£*et f?raddress"ig: Expression of
a WQBEL below a level of quantification
in a permit; the appropriate compliance
evaluation level (CEL)~; and permit
conditions to be included to ensure
compliance when the WQBEL is below
a level that can be analytically
quantified. This procedure is specified
in procedure 8 of appendix F of part 132
of this proposed Guidance. '
- , The Great Lakes Guidance requires
that the actual, calculated WQBEL he
expressed in each permit. Even though
a WQBEL cannot be measured
'analytically, it mustbe specified. In
addition to the exact WQBEL, the
permit must specify the analytical
method to be used to analyze the
monitoring samples; the CEL; and the
measurement frequency. The analytical
methods used to analyze wastewater
samples must be "ones specified in or '
approved as an Alternate Testing
Procedure under 40 CFR part 136. This
portion of the Great Lakes Guidance
.closely follows the guidance of section
There are many possible ways of
defining a CEL, Some examples in
current use are: .ML, method detection
limit (MDL), and practical -
quantification level (PQL). The Great
Lakes Guidance follows the TSD
recommendation in that the proposed
CEL for the purposes of this procedure
is the ML. The GEL is defined in 40 CFR
132.2 of the proposed. Guidance as the
ML. The ML is defined in 40.CFR part
136 as the level at which the analytical
system gives recognizable spectra and
acceptable cah'bration points. An ML is
back calculated from method-specific
weights and injection volumes. The use
of MLs in evaluating acceptable
quantification has been used by EPA in
the development of the 1624 and 1625
organic analytical methods (40 CFR part
136), and the. 1613 analytical method as
proposed in 56 FR 5090. In addition,
EPA is in the process of developing
additional MLs for the other analytical
methodologies.
When MLs are not available for a
pollutant, the permitting authority must
still specify a CELin the permit. The
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20978
Federal Register / VoL 58, No. 72 /Friday. April 16, 1993 /Proposed Rules
permitting authority has the discretion
to select the GEL in these instances. EPA
expects that the permitting axithority
will select a CEL that reflects the similar
performance of the ML, that is, the CEL
defines the lower bound of
quantification of a chemical analytical
method, ,
There are several ways that permuting
authorities may specify the CEL in the
absence of a ML. One way is to use the
MDL specified in 40 CFR part 136. The
MDL is the minimum concentration of
a substance that can be measured and
reported with 99 percent confidence
that the analyte concentration is greater
than zero and is determined from the
analysis of a sample to a given matrix
containing the analyte.
Another possibility is the minimum
quantification level (MQL). MQLs have
been developed as an interim measure
in the absence of strictly defined MLs.
An MQL is defined, similar to the ML,
as the lowest concentration at which a
particular substance can be
quantitatively measured. MQLs for
priority pollutants are based upon a
literature search of existing information.
The primary source selected was the
Contract Required Quantitation Levels
(CRQLs) and Contract Required
Detection Levels (CRDLs) which were
developed under the Contract
Laboratory Program administered under
CERCLA. When CRQLs were compared
with the MLs for similar gas
chromalography/mass spectroscopy
(GC/MS) methods, the results showed
that the levels are within the same order
of magnitude. Therefore, defining MQLs
as CRQLs or CRDLs appears to be
appropriate as an interim measure
where MLs have not yet been
developed. EPA would like to receive
VAWW w*wwwv*» ***** ,.•,——— »-^»T
comments on the use of MDLs, MQLs or
any other measure of the threshold of
quantification as an alternative CEL hi
the absence of MLs. ...
Procedure 8.A allows the permittee to
demonstrate that a higher CEL is
appropriate because of matrix
interference. Quantification levels are
unique for each selected analytical
method. The presence of other
pollutants in the effluent may cause
interference with the analysis and affect
the level at which quantification can be
assessed. This matrix interference could
raise the level at which one is able to
determine that a pollutant is
quantifiable.
The proposed Guidance in procedure
8 B specifies that a narrative statement
should be included hi the permit. This
statement must explain that the WQBEL
for the pollutant is less than the ML.
This statement clarifies to both the
permittee and the public that it is not
currently possible to analytically
measure at those levels with available
methods and that other procedures for
assessing compliance with the effluent
limit wi5.be used. ,
Procedure 8.C of the proposed Great
Lakes Guidance proposes text be
included hi each permit that defines
compliance with the CEL for maximum
daily permit limits, average weekly
limits, and average monthly limits.
Procedure 8.C states that any discharge
of a pollutant in amounts greater than or-
equal to the daily CEL for that pollutant
is an exceedance. Procedure 8.C further
states that, when a permit contains a
weekly or monthly limit, all discharges
sampled during such time period be
averaged according to" methods
established by the permitting authority,
with the average value compared to the
weekly or monthly CEL to determine
compliance. .
Usually, when assessing compliance
with weekly or monthly average permit
limits, the limit is compared to an
average of samples taken during the
relevant time period. The permittee is
required to supply the minimum
required number of samples, and must
supply data for additional samples if
taken from the appropriate period of
tune. In some cases, the permit may
require only one sample to assess
compliance. If one sample is required
and supplied, then it represents the
average concentration of that pollutant
for the entire period of interest.
When the WQBEL is below the CEL,
and the effluent data set includes both"
quantifiable and non-quantifiable
samples, the compliance determination
is not simple. In this situation, some
method must be developed for
"averaging" these non-quantifiable
values to assess compliance with
weekly or monthly average limits.
Current EPA Guidance does n
\jujLi.o*j.w f " **• vjfc**wujj.wJ CLOGS HOc
specifically address this issue, and
today's proposed Procedure allows
permitting authorities to specify then-
own methods for "averaging" values in
this situation. EPA invites comment on
whether the proposed Guidance should
require Great Lakes States and Tribes to
adopt uniform methods for averaging
quantifiable and non-quantifiable values
in this situation and, if so, what such
methods should be.
When a WQBEL is below the ML, one
cannot make a definitive statement as to
whether or not the concentration of the
pollutant in the effluent is above or
below the WQBEL. Because of this
constraint, other requirements are
necessary in order to increase the
likelihood that the concentration of the
pollutant in the effluent is as close to
meeting the WQBEL as possible.
Procedure 8.D of the proposed Great
Lakes Guidance requires that a pollutant
minimization program (PMP) be
specified in the permit in this instance.
This program would require a facility to
develop a pollutant minimization
program to reduce all quantifiable levels
of the pollutant in all internal or
indirect wastewater streams
contributing to the permittee's
wastewater collection system to
maintain the effluent at or below the
WQBEL. A PMP shall include, but not
be limited to the following: Annual
review an(l semi-annual monitoring of
sources of the pollutant, quarterly
monitoring of the pollutant in the
influent to the treatment system .
submittal of a control strategy for
reducing loading of the pollutants of
concern to the treatment system,
reporting of actions which are
consistent with the control strategy as
the sources of the pollutants are
discovered, and annual status reporting
of activities and accomplishments. EPA
invites specific comments regarding
whether the conditions otthe PMP are
appropriate, including whether the
frequency for monitoring of the sources
of the pollutant (procedure 8.D.1) and
the influent (procedure 8.D.2.) are
appropriate. -
EPA expects the PMP to recognize
that there are practical constraints on
treatment capabilities. Therefore, EPA
does not view the PMP as a zero ''
discharge requirement. Instead, it is
viewed as a means to ensure that
WQBELs are achieved. The effects of the
PMP may be to reduce all levels of the
substances hi the internal streams to
non-detectable levels, but this is not
equivalent to a zero discharge
requirement. A PMP-type requirement is
consistent with the Guidance found in
section 5.7.3 of the TSD and in the May
21,1990 Strategy. .
A permittee may consider cost-
effectiveness hi developing a pollutant
minimization program. In considering
alternative elements of a pollution
minimization program, the permittee
may choose to consider the cost-
effectiveness of each element. EPA
solicits comments on whether the final
Guidance should allow a facility to
consider cost-effectiveness in
developing a pollutant minimization
program, and if so, what data the facility
should consider in developing the
program.
Procedure 8.E specifies that if all
samples of the effluent are below the
CEL for the maximum daily limits, all
required averages are below the CEL for
the average weekly and monthly limits,
and the conditions of the PMP are met,
then the permittee will be deemed in
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Federal Regisit0r / VoL 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
20979
. compliance with the permit. If one of
tie conditions of the,PMP is not met,
the permittee is in violation: of the . ,--
permit conditions. If an effluent sample
is above the CEL for tie maximum daily
limit and the average of samples are
. above the CEL for weekly and monthly
average limits, then the conditions of
procedure 8.G are invoked. '•",'•
Special requirements are specified kt
procedure 8.F of the Implementation
Procedures for the cases where BCCs are
limited below the quantification level.
The special requirements generate
additionalinformation with which to
use in judging whether or not the,
discharge is contributing enough of a
;s pollutant to cause bioaccumulation of
the pollutant In fish tissue. The
additional provisions require the
permittee to determine if the pollutant
from the effluent is bioconcentrating or
bioaccumulating hi fish tissue. This
condition is also consistent with the
section 5.7.3 of the TSD and May 21,
1990 Strategy. Approaches to determine
whether a pollutant is bioconcentrating
or bioaccumulating are specified in the
proposed Great Lakes Guidance. EPA ,
believes that there are many acceptable
approaches to performing fish
monitoring or effluent bioconcentration
studies. Examples,of acceptable
methods are: "U.S. EPA Interim
Methods for the Sampling and Analysis
of Priority Pollutants in Sediments and
Fish Tissue" {U.S. EPA, 1982), and
"Draft Assessment and Control of
Bioconcentratable Contaminants ;in
Surface Water" (U.S. EPA, March 1991),
which are available in the '
administrative record for this
proceeding. The regulatory authority
may require that other approaches be
used; If the results of the studies show
that the effluent is bioconcentrating or
bioaccumulating at unacceptable levels,
the control strategy, as part of the PMP,
must be reviewed and modified
appropriately. :
The proposed Great Lakes Guidance
provides two approaches for
.determining unacceptable tissue levels.
One approach is" to estimate
! concentrations of a pollutant in
receiving waters based upon the levels
of the pollutant in the fish tissues
calculated using the criteria equations
and assumed inputs. If this
concentration is above the water quality
standards, then ways to modify the
control strategy are warranted and
necessary. A complementary approach
is to compare the level of the pollutant
in the monitored fish tissue to the level
used to develop the water quality
criteria for that pollutant.'In both cases,
the variability of the bioconcentration
test an^ the calculated dilution of the
effluent flow in the receiving water
must be considered. EPA welcomes
comments on these and differing
approaches to defining unacceptable
tissue levels and the extent to which
"unacceptable tissue levels" should be
defined in the text of the procedure..
In addition,.the permitting authority "
may impose other conditions, as
provided in procedure 8.H, upon .
permittees on a case-by-case basis to
require: Derivation and/or use of new
analytical equipment and/or methods;
use of internal waste stream monitoring
and mass balance modeling techniques;
and use of any other innovative
monitoring techniques and results with
which to assess compliance with the
WQBEL. This section acknowledges the
authority of a State under section 510 of
the CWA to require more stringent
provisions. .. : ;
3. State and Tribal Adoption
Requirements
In order to achieve consistent
application of this procedure, the Great
Lakes State or Tribe must adopt a
procedure that requires: The actual
WQBEL derived from the WQS to be
imposed in the effluent limitations'
table of the pennit; the minimum level
as the CEL of preference, when
available; PMPs to he specified in all
permits so that internal sources of the
pollutant are being reduced; when the
WQBEL is for a BCC, studies to
demonstrate whether bioaccumulation
or bioconcentration is occurring in fish,
tissue due to the discharge be
submitted, and the results used to .
modify the PMP, as necessary; and one
quantified sample of the pollutantfat or
above the CEL) to be considered as an
exceedance of the maximum daily limit
for that reporting period, and any
average above the CEL to be considered ;
as an exceedance of the average limit for
that reporting period. The text does not
have to be adopted verbatim. However,
the permitting authority must show that
the above conditions are met.
4. Options Considered
During the Great Lakes Water Quality
Initiative process, it was suggested that
numerous violations of the WQBEL will
occur although actual effluent
concentrations may be below the CEL,
due to .analytical uncertainty
surrounding measurements at the CEL.
Suggestions were made that other
measurement levels, like the MDL or the
PQL, would be more appropriate. EPA
does not believe that the MDL or PQL
would be more appropriate, because: the
MDL is not a measure of.quantification,
and the PQL (which is typically set as
. a multiple 5 or 10 times the MDL) is not
as precise as the ML. EPA invites
specific comments if whether other
levels would provide a more valid :
determination of the ability of an
analytical method to quantify a
pollutant concentration and the ,-
published scientific data supporting
such levels. '
Alternate text was discussed by the
Initiative Committees during
. development of this proposed provision.
This text was "Include permit language .
clarifying that any discharge of the
pollutant at or above the detection level
is an exceedance requiring further r'
action." This text incorporates two
concepts: t . - .
a. Averaging effluent samples for a
particular reporting period would not be
allowed; and . :... .
b. Permitting authorities would have
the authority to require further action to
confirm exceedances of WQBELs. The
following text will discuss the
Technical Work Group's reasons and
other options considered.
The Initiative Committees considered
many approaches for assessing values of
pollutant measurements below the - ,
quantification level. The original
Technical Work Group proposal of.
prohibiting the averaging of effluent
samples was chosen as a simple,
conservative approach to assessing
compliance. As mentioned previously,
when a WQBEL is below a detection or
• quantification level, and the effluent
data set includes both quantifiable and
non-quantifiable samples, the
compliance determination is not simple.
The Technical Work Group believed
that when a pollutant is detected or
quantified in compliance monitoring, .
then it is known that the pollutant is
present in the discharge at levels above
the magnitude of the WQBEL, Limited
'agreement was reached on appropriate
means for averaging detected/quantified
values with non-detected/non-
quantified values.,
EPA did not believe that the
conservative approach would • , ,
necessarily be appropriate in all cases,
and therefore revised paragraph C of
procedure 8 of appendix F as it is
published today. Procedure 8.C states
that an exceedance of an average limits
occurs with respect to a reporting period
when the average of a pollutant is above7
the CEL during that averaging period. '
The specific means for calculating the
average is left to the discretion of the
permitting authority.
Several other approaches for assessing
values of pollutant measurements below
the quantification level were discussed
during the Initiative Cpmmittees' Work-
_ Group meetings.and during the drafting "
of this proposal package. An alternative ;
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
approach would be to specify the means
fot averaging by assigning a value
somewhere in the range from zero to the
CEL, to the non-quantified samples. A
value which assigns an equal amount of
risk to the environment and to the
discharger is 50 percent of the CEL or
the WQBEL, whichever is less. Another
approach would be to assign a zero
value to all samples below the
minimum value, average all of the
samples and then compare the result to
the WQBEL (even if less than the
minimum level). If this approach was
selected in the final Guidance, this
would require changing the definition of
the CEL to equal the WQBEL for both
weekly and monthly average effluent
limitation. EPA invites comments on
those alternative approaches, any
combination of approaches, or other
approaches to address this issue.
Additional methods for evaluating
compliance with mixed data sets of
quantified and non-quantified samples
are as follows: First, compliance could
be assessed by calculating the
percentage of quantified samples from
the total number of samples, and
declaring noncomplianoe when the
percentage of quantified samples is
equal to or greater than 50 percent.
Another option would be to substitute
lha WQBEL value for the values which
aro below the CEL, average all values,
and then compare the results to the CEL.
If the results are below the CEL, then
compliance is declared. If the results are
at or above the CEL, then
noncompliance is declared. Neither of
these approaches were considered by
the Technical Work Group, however.
EPA believes that these proposals bear
some merit and welcomes comments on
these and other methods for averaging
effluent samples or for accounting for
non-quantified samples in determining
compliance with effluent limits which
are below the level of quantification.
The second concept of the Initiative
Committees' version of paragraph C of
procedure 8 was addressed because the
Committees believed that this text
would reduce the effects of potential
analytical uncertainty at the detection
level. Comments received during the
drafting process expressed that when
the concentration is close to the DL, the
uncertainty regarding the assessment of
detection and/or quantification appears
to be higher. Chemists typically use
some degree of judgment in assessing
tho amount of a pollutant during the
process of analysis. Judgment is used to
quantify the amount of a pollutant that
is present in a sample, no matter the
definition of the detection level. This
judgment may, hi some cases, result in
false positives, i.e., the analysis
indicating the presence of a pollutant
when the pollutant actually is not
present.
The Initiative Committees believed
that for analytical results close to the
detection level, since there may be.
uncertainty regarding its validity, the
regulatory authority should be allowed
to reserve judgement regarding the
compliance status of that sample. Permit
authority would require further action,
for example, increased monitoring of the
pollutant for an extended period of
time, of the permittee before a final
compliance judgement would be made.
It was envisioned that once the
additional monitoring work was
provided or other appropriate actions
w.ere completed, an assessment of
whether the original point violated the
limit would be made by the regulatory
authority. EPA did not include this text
in proposed procedure 8 of appendix F
because EPA maintains that any
exceedance of a permit limit including
a WQBEL is a violation as defined by
section 309 of the CWA. Of course,
dischargers always have the opportunity
to demonstrate that any measurement is
inaccurate or invalid. In addition,
because the CEL of preference is the ML,
EPA believes that the analytical
uncertainty of false detects is less of a
concern than if a true detection level
were used as the CEL. EPA, however,
welcomes comments on all aspects of
this issue, including the appropriateness
of the original text prepared by the .
Initiative Committees.
I. Compliance Schedules
A compliance schedule in this context
refers to an enforceable sequence of
interim requirements leading to ultimate
compliance with the requirements of the
Clean Water Act. Procedure 9 of the
implementation procedures allows
schedules for compliance in peftnits
with WQBELs hi specified
circumstances. However, the permitting
authority has discretion not to include
compliance schedule provisions.
The circumstances under which a
compliance schedule may be provided
depend on whether a new discharger, an
increasing discharger, or an existing
discharger i& involved. For purposes of
procedure 9, a "new discharger" is
defined as any facility which
commences discharging on or after the
effective date of this regulation._An
"increasing discharger" is defined as an
existing discharger which on or after the
effective date of this regulation has an
increase in flow, concentration or
loading from that which was previously
specified in its permit. An "existing
discharger" is defined as any facility
which commenced discharging prior to
the effective date of this regulation,
provided it is not an increasing
discharger. •
Schedules of compliance are not
available for new or increasing
dischargers. Procedure 9.A provides that
when a permit is issued, reissued, or
modified to contain an effluent
limitation derived from Tier I criteria,
Tier II values, whole effluent toxicity
criteria, or narrative criteria for a new or
increasing discharger, the permittee
shall comply with the new effluent
limitations upon the commencement of
the new or increased discharge.
The Initiative Committees believed
that schedules of compliance for .
WQBELs should not be available for
new or increased dischargers because
their changed operations would occur
on or after the effective date of this
regulation; and hence after they are. on
notice of the water quality standards
which are required under the Great .
Lakes Initiative. The Initiative
Committees believed that it is
reasonable to expect immediate
compliance with effluent limits derived
from the Tier I and Tier II
methodologies in these circumstances as
soon as the new or increased discharges
commence and that this action would
further the goal of reducing discharges
to the Great Lakes System as soon as
possible. • -
Procedure 9.B addresses the
circumstances under which compliance
schedules would be appropriate when
new or more restrictive limitations are
established in permits for existing
dischargers. This section provides that
when a permit for an existing discharger
is modified or reissued to contain more
stringent effluent limitations due to Tier
I criteria, Tier II values, whole effluent
toxicity criteria, or narrative criteria, the
permit may allow a reasonable time, not
to exceed the term of the permit or three
years, whichever is less, to comply with
the new limitations. As a matter of
practice, EPA has generally supported •
and allowed a three year maximum on
compliance schedules in discussions'
with States, if this does not extend past
the term of the permit. This time frame
is also consistent with that provided
pursuant tb section 304(1) for Individual
Control Strategies. During this period,
the permittees must comply with either
the terms of the previous permit or any
more stringent interim limitations and
other requirements specified in the
schedule of compliance.
If a permit establishes a schedule of
compliance which exceeds one year
from the date of the permit issuance, the
schedule shall set forth interim
requirements and the dates for their,
achievement. Interim requirements may;
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Federal Register / Vol. 58, No. 72 1 Friday,-April 16, 1993 / Proposed Rules 20981
be construction milestones; they need,
not necessarily be interim effluent
limitations. The time between interim
" dates for compliance schedules under
this provision may not exceed one year.
If the time necessary for completion of
any "interim requirement is more than
one year and is not readily divisible into
stages for completion* the permit shall
specify interim dates for the submission
of progress reports toward, completion of
the interim requirements and indicate a ~
projected completion date. Specification
of interim compliance dates is cumrently
required in all NPDES permits issued by
EPA or authorized States. (40 CFR
122.47,123.25).
• Procedure 9.C provides the discretion -
for the permitting-authority to provide
additional flexibility for complying with
Tier II limitations in modified or
reissued permits for existing
dischargers, to accommodate the
situation where additional studies may
provide the basis for developing a Tier
I criteria or modifying a Tier II value.
Under these circumstances, the permit
- may provide up to two years from
permit issuance for completion of.
specified studies (this would occur
during the up to three-year period for
compliance provided under procedure
9.B}. If such studies are completed in a
timely fashion, and new criteria or
values are developed, the permit may be
reopened and modified to reflect the
new Tier I criteria or revised Tier jl
value. As long as the specified studies
are completed, whether or not they turn
out to justify new criteria or values, the
permittee may have a reasonable time,
within the remaining term of the permit;
to comply with the limit(s) in question.
Any additional time which will be
granted to a permittee should be ~ ,
appropriate for the activities which the
permittee will have to undergo in order
to achieve compliance with the revised
WQBEL, or, if hot revised, the originally
established WQBEL. The reasonable
time will be determined by a permitting
authority on a permit-by-permit basis.
For example, if the WQBEL is revised to
become less stringent and minor process
changes are necessary to achieve
compliance, then no additional time
• may be necessary or additional time ••
may not be more than six months. On
the other hand, a facility may need to
add on additional treatment involving
construction. In this case, two years may
be appropriate in order for the facility
to achieve compliance. In any case, due
to the.fact that the permits must be
modified in order to incorporate 'the
results of the studies the public would
have an opportunity to comment upon
the appropriateness of any extension of
the compliance schedule as well as .the
modified WQBEL. In addition, EPA has
review authority to ensure -that the
additional time period is "reasonable"
and not based upon a" standard practice
of granting additional time which
equates to the remaining term of the
permit. If the studies are not completed
in a timely fashion, the permittee must
comply under the original not-to-exceed
three-year schedule. In addition, the
permittee may not presume that a
revised WQBEL has been established or
additional time for compliance has been
provided, until the permitting authority
has modified the facility's NPDES
permit to reflect these changes.
EPA has long had a practice of
considering reasonable schedules of
compliance in permits based oh newly
adopted or revised water quality
standards promulgated after July 1,
1977. Recent orders in In Re Star-Kist
Caribe, lac,, NPDES Appeal No. 88-5,
have emphasized the need for States
and Tribes to provide specific -
authorization for such schedules. In
light of the deadline in'section
301(b)(i)(C) of the Clean Water Apt,
which requires that permits assure
compliance with applicable water
quality standards, these Orders state
that schedules of compliance for
limitatipns based on post-July 1,1977,
standards are prohibited unless the
standards themselves or State or Tribal
implementing regulations expressly
authorize such schedules.
- Because the implementation
procedures proposed today are expected
to be adopted by States and Tribes as
part of their standards programs or
implementation regulations for the ,
Great Lakes System, such adoption will
allow the proposed use of schedules of
compliance in NPDES permits in those
States and Tribal lands. Of course, no
State or Tribe is obligated to include a
schedule of compliance in a particular
permit under the proposed procedures
and States or Tribes can be more
stringent by not providing for
compliance schedules. Because the
pollutants in Table 5 are not addressed
by procedure 9, any States or Tribes
wishing to provide schedules of-
compliance for limits based on .criteria
. for Table 5 pollutants will heed to do so
separately. , . ' •
In addition, facilities being regulated
under section 304(1) of the Clean Water
Act (CWA) are not exempt from their
304(1) compliance requirements. For
example, if facilities are located in one
of the Great Lakes States or on Tribal
land but were listed on a 304(1) list,
their 304(1) compliance-requirements
cannot be extended by any compliance
schedules adopted pursuant to the <
proposed Great Lakes .Water Quality
Initiative Guidance.
Another issue which was raised
during the development process of
procedure 9 is whether the anti- .-:'.-
backsliding requirements of section .
402(6) of the CWA would apply to
limits which have a scheduled date of
compliance beyond the effective date of
the permit. The anti-backsliding
provision of the CWA prohibits
reissuing or modifying an NPDES
permit to include less stringent effluent
limitations unless certain tests are met
The proposed Guidance provides that
anti-backsliding restrictions do not
apply to revisions to effluent limitations
made before the scheduled date of
compliance for those limitations.
Additional discussion of anti-
backsliding requirements is contained
in section II.D of today's preamble^
EPA would like to receive comments
from the public regarding the three
approaches outlined concerning
compliance by dischargers .with the Tier
I criteria and Tier ri values presented in
Procedure 9.A through C, inclusive, of
appendix F. For example, do the
timeframes detailed hi Procedure 9.B
and ,C provide sufficient time both to .
comply generally, and, in particular, to
adequately complete the necessary
studies referred to in these sections? In
addition, EPA specifically invites
comment .oh whether it is appropriate to
provide for extension of a compliance ,
schedule where a permittee conducts a
study'as to the appropriateness of a Tier
JI limitation. EPA has traditionally taken
the position that a. facility can challenge,
study or litigate both technology-based
and water quality-based terms and
conditions of a permit on its own time,
but that these activities do not extend
otherwise applicable compliance dates.
EPA invites comment on whether the
approaches described in Procedure 9.C
are appropriate. EPA would also
appreciate comment from the public as
to whether the time permitted for
compliance under the Guidance is
appropriate, i.e., if no studies are done,
up to three years; or, if the studies are
'done, whether or not they justify less
stringent limits, then up to five years. In
addition, another topic for consideration
is what factors; or procedures should be
used by the permitting authority to
assess what would be the reasonable
amount of any of the compliance
period(s) or interim schedule(s); EPA •
• also invites comments on the proposed
text precluding compliance schedules
for new or increasing dischargers; and
the proposed definitions of new,
existing, and increasing dischargers .
applicable to compliance schedules.
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
IX. Executive Order 12291
A. Introduction and Rationale for
Estimating Costs and Benefits for the
Great Lakes Water Quality Guidance
Executive Order 12291 requires EPA
to prepare a Regulatory Impact Analysis
(RlA) for major regulations, which, are
defined by certain levels of costs and
impacts. For example, the Executive
Order specifies that a regulation
imposing an annual cost and benefit to
the economy of $100 million or more is
considered major under the terms of the
Order. According to the Executive
Order, the Regulatory Impact Analysis
should contain descriptions of both
potential costs and benefits.
Under the Clean Water Act, costs are
not directly relevant in establishing
water quality criteria. However, if a
range of scientifically defensible criteria
that are protective of the designated use
in question are identified, costs may be
considered in selecting a particular
criterion within that range. In addition,
under EPA's regulations, certain costs
can be considered in the context of use
attainability analyses, variances, and
antldegradation. Moreover, as a matter
of good government, EPA likes to be
aware of costs and benefits of its
proposals. Accordingly, the question of
costs and benefits has been an integral
part of the deliberations involving the
States and EPA in the development of
tho Great Lakes Water Quality Guidance
(GLWQG). In addition to the
requirements set forth in Executive
Order 12291, the States of Ohio,
Michigan and Wisconsin have
specifically requested that EPA examine
the costs and benefits of the Initiative.
Some members of the Public
Participation Group also expressed a
concern during the Steering Committee
meetings that the posts to point sources
could be sizeable. Other public
comments expressed concern about
potential benefits. During the Steering
Committee deliberations in November
and December 1991, EPA expressly
committed to estimate various costs and
benefits that could accrue from the
proposed GLWQG.
Toe following discussion describes
how EPA has estimated both costs and
benefits associated with the proposed
Guidance, Aggregate costs are estimated
for all direct and indirect dischargers in
the Great Lakes System. Benefits and
costs are assessed for direct industrial
and municipal dischargers at three sites
in the System, The results of these case
studies are not appropriate to use in
evaluating the aggregate benefits and
costs of th« proposed GLWQG. EPA is
requesting comments on the
methodologies used to estimate both
costs and benefits. Commenters should
provide data to support their comments.
EPA will evaluate all comments and
supporting data received through the
public comment process. As noted
above, E.0.12291 requires EPA to
prepare a Regulatory Impact Analysis
for proposed and final major rules. The
studies described below have been
submitted to Office of Management and
Budget (OMB) to fulfill this
requirement. These cost and benefit
studies are summarized below. The
documents underlying this summary are
available in the administrative record
for this rulemaking.
B. Overview of Projected Costs
Attributable to the Great Lakes Water
Quality Guidance
1. Introduction
EPA acknowledges that some point
source dischargers, including cities and
towns, will incur costs in complying
with the requirements of the GLWQG
after the proposed Guidance is
promulgated and Great Lakes States and
Tribes have adopted it. These
requirements, when added to current
State or Tribe water quality standards
and permitting regulations, could
require additional construction of
treatment facilities and/or process
changes, including pollution prevention
and waste minimization programs. The
magnitude of these incremental costs
would depend on the types of treatment
or other pollution control installed, the
number and type of pollutants treated,
and implementation of such pollutant
management programs as pollution
prevention, community and facility
waste minimization programs, and best
management practices in a variety of
areas.
Similar sources of costs and the
variables affecting costs would also
apply to indirect industrial dischargers
to the extent that the industrial
discharger is a source of pollutants
discharged to a Publicly Owned
Treatment Works (POTW). In addition,
the POTW may incur costs for
expansion, operational changes,
additional treatment, modified .
pretreatment programs and increased
operator training.
Monitoring programs are another
source of potential incremental costs to
dischargers and regulatory authorities.
Monitoring programs to generate
information on the existing quality of
water and the types and amounts of
pollutants being discharged are
potentially affected by the imposition of
the proposed GLWQG criteria. The
addition of criteria and values for toxic
pollutants as a result of States' or Tribes'
use of the Tier I and Tier n
methodologies of the GLWQG can lead
to additional compliance monitoring by
facilities and regulatory authorities as
well as additional ambient water quality
assessment costs. However, this
monitoring is not solely triggered by the
adoption of GLWQG criteria or
methodologies, but is contingent on the
States' implementation actions in
discharger permits add other control
mechanisms. Additionally, it is possible
that pollution prevention type measures
(source reduction and increased
recycling) would enable dischargers to
reduce their discharges, eliminate
pollutants, and therefore decrease
monitoring.
Nonpoint sources of pollutants
covered by the proposed Guidance may
also incur increased costs to the extent
that best management practices need to
be modified to comply with the revised
water quality standards resulting from
the aquatic, human health and wildlife
criteria adopted under the proposed
Guidance. However, there is no Federal
permit program requiring control of
nonpoint sources comparable to that for
point sources. Some Great Lakes States
have developed regulatory programs
under State law that will require some
nonpoint source dischargers to comply
with the numeric criteria and values
proposed hi the proposed Guidance. As
these State Nonpoint Source
Management Plans are implemented in
the Great Lakes, best management
practices will begin to reduce discharges
from nonpoint sources within an
increasing number of drainage basins
and will require application of the
antidegradation provisions specified in
the final Guidance. These costs are not
directly attributable to this proposal.
2. Methodology for Estimating Costs to
Point Sources Attributable to the
Proposed Great Lakes Water Quality
Guidance
EPA decided to focus its initial
assessment on categories of industries
and municipalities that would be both '
likely to be affected by the proposed
Guidance and serve as the bases for a
reasonable extrapolation of costs to the
universe of Great Lakes System
dischargers. Based on a review of lists
that States generated and of permits
issued since March 1991, EPA assumed
that the largest aggregate impact would
most likely be on the major direct
dischargers. EPA defines major
municipal dischargers as those that
serve over 20,000 persons and have
flows in excess of 1,000,000 gallons per
day; there are 316 major municipal
dischargers in the System.,
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20983
In defining major industrial ••/.
dischargers, EPA considers several
factors, including the amount of toxic ..
pollutants in the discharge as Well as
volume discharged; there are 272 major
industrial dischargers in the Great Lakes
System, Thus, the GLWQG could affect
a total of 588 major industrial and
municipal dischargers.
EPA also distinguishes a second.
group of dischargers, minor dischargers,
that fall outside of these definitions;
Minor facilities may discharge
contaminated process wastes that could
have a significant toxic component, or
have other characteristics that would be
the focus of the GLWQI. There are 3,207
such minor dischargers located.in the
Great Lakes basin. '.
'.,. These are all the facilities currently
permitted by either EPA or the eight
Great Lakes,States authorized to
administer the National Pollutant
Discharge Elimination System (NPDES)
program—588 majors arid 3,207 minors,
for a total of 3,795 permittees.
The .subset of facilities used in the
cost study was selected primarily from
.the universe of major facilities to enable
EPA to reasonablyextrapolate the most
significant costs in the Great Lakes basin
as a whole. After reviewing a variety of
lists of facilities—permits issued since
March 1991, those recommended by
each State and the lists, of major and
minor facilities—EPA randomly
selected 59 facilities (50 major arid nine
minor). These facilities represented a
limited, but practical, number of:.
dischargers for estimating costs and for
extrapolating these costs to estimate
total costs for all direct dischargers in
the'Great Lakes basin. EPA conducted a
detailed review of these facilities that it
considered representative of all tjfpes
and sizes of facilities iri the Great Lakes,
basin. , ' ' . '".-'.''
• Due to differences in the universe of
major and minor dischargers, two
separate methodologies were used to
select representative major and minor
facilities. For major dischargers, all •
randomly selected facilities were
grouped into 10 categories .which
included nine primary industrial groups
and a category for municipalities, also
known as Publicly Owned Treatment
Works or POTWs. The nine industrial
categories are: Mining, Food'and Food
Products, Pulp and Paper, Inorganic
Chemical Manufacturing, Organic
Chemical Manufacturing/Petroleum
Refining, Metals Manufacturing,-
Electroplating/Metal Fabrication, Steam
Electric Power Plants, and
Miscellaneous facilities.
This initial categorization of major
facilities was then stratified by flow
within each, category. While each
industrial category was divided into two
or three flow strata, these distinctions
were tailored to each category. The
differing flow distinctions were used to
decrease reliance on estimating cost
strictly based on flow rates and to
decrease the skewing effect on the
analysis of greatly varying flow rates
between categories. EPA feels that flow
distinctions chosen independently for
each category represent a natural
clustering of the flow rate data that put
roughly equal numbers of facilities into
each flow stratum. These distinctive
flow strata were designed to address the.
following objectives:
a. Ensure that the strata allows for
random selection and costing of at least •.
two sites from each flow strata arid
category of discharge; :
b. Ensure a balance in the number of
sites Within each flow strata to provide
roughly proportional representation iri
the sample of sites with varying flows;
c. Ensure enough flow divisions so
that reported flows differ as little as
possible within any single flow strata;
and •-.'.-.'
d. Ensure allocation of more sites to
discharger categories with a greater
number of facilities to allow more flow
'strata to be formed within these
categories. -.--. , .'.-'•- - .
These objectives allow for greater
• precision in estimating cost and allow
for more efficient extrapolation of the
cost estimates to the entire System^
Since POTWs represented the largest
category of major.dischargers, more
POTWs were selected from that group to
ensure a more statistically reliable
representation.
Further, a number of minor facilities
were evaluated even though they are not
expected to discharge a large number or
quantity of toxic pollutants as compared
" to major dischargers. Because little or no
compliance costs are anticipated by
minor dischargers, EPA analyzed a .',
limited number of randomly s'elected .
minors to verify that assumption.
Furthermore, because EPA has. little or
no flow'data:for minor dischargers, it is
not possible to adopt a flow-stratified
analytical plan similar to that for
majors. For each facility under review,
the most current, necessary NPDES
permit data and background information
was collected to: calculate the limits
•;that would be anticipated from current
regulatory requirements (if hot
incorporated into the current permit);
and develop additional permit
requirements based on the proposed '
Guidance. EPA gathered information
from State and Regional files that
included permit applications, permit
fact sheets or rationale, inspection
reports, discharge monitoring reports,
. pretreatment reports, short-term waste
characterization studies,'receiving '-•'-»
stream low-flow scenarios and total "•
maximum daily loads/waste .load
allocation reports, and,any other readily
available information. In most instances,
State permit writers were directly
contacted to: verify collected
information; assist iri the interpretation
of previous permit limit calculations;
and assist in interpreting water quality
standards and implementation
procedures adopted in the past two
years to comply with section
303(c)(2)(B),of the Clean Water Act.
Permit writers and water quality experts
from the following organizations were
consulted: Minnesota Pollution Control
Agency, the New York State Department
of Environmental Conservation, the
Michigan Department of Natural
.Resources, the Ohio Environmental
Protection Agency, the Wisconsin
Department of Natural Resources, the
Indiana Department of Environmental
Management, the Pennsylvania
Department of Erivironriiental
Resources, the Indiana United States
Geological Survey, the Michigan United
States Geological Survey, the Minnesota
United States Geological Survey and
EPA Regions 2, 3, and 5.
For each facility on the review list,
new permit limits and additional permit
conditions were developed based on the
implementation procedures in the .
proposed Guidance. The proposed ,
'criteria would require some permitted
-facilities to meet new limits and adopt
other permit conditions such as whole
effluent toxicity testing and additional
monitoring. The limits developed for -
estimating costs were calculated for
those 34 pollutants for which numeric
Tier I and Tier 31 criteria and values
have been proposed. For a given facility,
only those pollutants that were detected
in the discharge, or expected to be '•
- present in the discharge but were
reported as not detected because less
sensitive EPA approved analytical
methods were used, were evaluated. ••
The need for whole effluent toxicity
limits and monitoring was also
evaluated in accordance with this
proposal. For each facility, limits were
calculated for the outfalls that contain
or may contain observed or anticipated
loadings for the pollutants of concern.
If the existing effluent limits for some
of the permitted facilities selected did
not reflect current State water quality
standards,and implementation policies,
these differences needed to be
accounted for prior to estimating the '.'
incremental difference between the
current requirements arid the GLWQG-
based effluent limits. Therefore, prior to
comparing the limits and conditions '••
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20984 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
that are based on the GLWQG, EPA
recalculated the permit limits to reflect
th® newly-revised State standards and
requirements that are based on the
adoption of toxic water quality
standards under section 303 (c)(2)(B)
(referred to here as baseline
requirements). This approach should
reflect more accurately differences
between existing effluent limits based
on newly-revised State requirements
and procedures required in the
Initiative, In other words, for older
permits, two sets of permit limits were
calculated—a first set of permit limits to
reflect the current, but not fiilly
implemented, regulatory baseline
requirements for facilities, and a second
set of limits to determine what the
GLWQG will add to these baseline
requirements.
In determining specific requirements
imposed by the GLWQG, it was
necessary to calculate wasteload
allocations for discharges to both the
open waters of the Great Lakes and their
tributaries, In doing so, EPA assumed
that the data necessary to calculate total
maximum daily loads (TMDLs) would
not ba available for specific pollutants
on specific receiving waters. Therefore,
EPA calculated site-specific wasteload
allocations for each discharger using
equations set forth in the draft
implementation procedures. Due to the
general lack of background
concentration data for receiving waters,
two different Waste Load Allocations
(WLAs) were calculated for each
facility. The first WLA assumed zero
background in the absence of
background data (WLA #1). The second
WLA assumed a value for background
concentrations where no background
data existed (WLA #2). The assumed
background value was based on the
average proportion of the actual
measurable background data from seven
facilities to the GLWQG criteria and
values. The assumed background values
wore approximately 50 percent of the
GLWQG water quality criteria and
values.
The proposed implementation
procedures do not contain specific
procedures for converting WLAs into
Water Quality Based Effluent Limits
(WQBELs). In this study, the dally
maximum WQBEL for a pollutant was
sot equal to tha WLA calculated to
protect the acute aquatic life criterion
(i.e., the Final Acute Value). Monthly
average WQBELs were set equal to the
most stringent WLA calculated to
protect chronic aquatic life, wildlife, or
human health criteria. There were
several instances when negative WLAs
were calculated for a pollutant. This
occurred duo to high background
concentrations of pollutants reported for
a receiving water. Since the
implementation procedures do not
contain procedures for dealing with
negative WLAs, two different sets of
WQBELs were calculated for each
facility, which resulted in different
compliance cost scenarios. In cases
where negative WLAs were calculated
using WLA. #1, the WQBEL was set
equal to the background concentration
(WQBEL #1); when negative WLAs were
calculated using WLA #2, then the
WQBEL was set equal to the most
stringent water quality criteria (WQBEL
#2). .
The specific assumptions and
protocols used in making these
calculations are set forth in the
Assessment of Compliance Costs
Resulting from Implementation of die
Proposed Great Lakes Water Quality
Guidance. This document is available in
the administrative record for this
rulemaking. EPA solicits any comments
on the methodologies used to estimate
costs, including the underlying
assumptions and the supporting data
used. Commenters should provide data
supporting their comments during the
public comment period to enable EPA to
conduct a thorough evaluation.
3. Determinations of Costs
The three main cost categories
assessed are:
a. Treatment costs associated with
installation, modification or expansion
of treatment systems;
b. Monitoring costs for facilities for
the purpose of tracking the presence of
toxic pollutants thought or known to be
in a discharge, but at levels too low to
justify direct regulation through effluent
limits; and,
c. Costs related to facility or system
management, such as enhancement of
pretreatment programs, special studies,
toxicity reduction programs, pollution
prevention programs and waste
minimization.
If the GLWQG-based effluent limits
were more stringent than the existing
effluent limits either in current permits
or calculated against current regulatory
requirements, then EPA developed costs
to comply with the more stringent
effluent limits on a facility-by-facility
basis. In developing these cost estimates
several factors were taken into
consideration, including:
i. Ability of the existing treatment
system and process to treat any or all "of
the pollutants for which GLWQG limits
have been calculated;
ii. Whether or not the incremental
amount of a pollutant or pollutants to be
evaluated were below treatable levels;
iii. Degree to which influent
concentrations of pollutants to be
treated are present at levels amenable to
existing treatment, or would require
additional treatment;
iv. Opportunities available for
retrofitting existing treatment systems in
terms of add-ons, process
enhancements, etc.;
v. Opportunities for source reductioi.
through pretreatment program •
modifications, pollution prevention,
waste minimization and best
management practices (of particular
importance for municipalities');
vi. Treatment options and costs
identified in EPA development
documents associated with policy,
guidance and effluent guideline
regulation.development; and,
vii. Costs for additional monitoring,
implementation of special conditions -
such as toxic reduction evaluations and
special studies to verify presence of
suspected toxicants.
These factors were applied to each of
the facilities reviewed. Each review is
documented in a facility-specific report
.that outlines the application of the
methodology, including the findings
and conclusions. These individual,
facility-specific review reports and the'
report collating the information from all
of the reviews are, available for review
in the administrative record. EPA
requests public comment on this
methodology, the facility reviews and
the tentative conclusions set forth
below.
4. Estimated Facility Compliance Costs
a. Basic Considerations. Following the
identification of pollutants of concern
for each facility and the development of
water quality-based effluent limits based
upon the proposed Guidance criteria
and implementation procedures, the
final step involved an estimate of costs
to the particular facilities reviewed. An
engineering analysis for each facility in
the sample was conducted to develop
potential compliance options. This
included a review of existing trea*
systems at the facility, and an
assessment of the need to add new
treatment or supplement existing
treatment capabilities. Having defined
the control options, the compliance
costs to facilities implementing each
option were estimated. Compliance
costs generally included treatment costs,
monitoring and operations and
maintenance costs, and a variety of one-
time costs of limited durations (e.g.,
waste minimization audits of
production processes).
In performing this analysis, EPA used
its own development documents for
effluent guidelines and standards, die
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20985
Office of Research and Development
Risk Reduction Engineering
Laboratory's RREL Treatability
Database, and other information that
was available in State or EPA records.
This information enabled EPA to, ;
develop estimates for the toxic effluent
levels currently achieved at facilities
and the levels-that could be anticipated
to be achieved with alternative
treatment systems. If this analysis
showed that additional treatment was
.; needed, unit processes were then
selected as additional end-of-pipe . '
. treatment. EPA generally assumecTthat
additional treatment would be added as
end-of-pipe because it did not have such
process-specific information such as
flows, treatment-in-place, process waste
characteristics or recycling capabilities
that would allow an assessment of other
potentially less expensive alternatives.
The estimates most affected by the end-
of-pipe assumption would be the size of
the treatment units because this
assumption had to be based on ,
treatment of the entire flow. Where
process-specific information was .
available, however, EPA attempted to
develop estimates for treating separate
• process waste streams. •
In several instances, additional end-
of-pipe treatment was not projected for
a facility. This was the case where
existing treatment facilities could
accomplish the required treatment, .
current permit requirements or
construction plans were already in place
to provide the additional treatment, or
the incremental amounts of pollutants
to be removed were minimal/In each of
these instances, it is not currently '.,
anticipated that there will be
appreciable treatment requirements
directly attributable to the GLWQG.
. b. POTW Costs. In the case of
municipalities, orPQTWs, compliance
costs are also a function of their ability
,to implement additional controls
through pretreatment programs they
administer. Therefore, in setting cost
estimates for these systems, -
consideration was'given to the number
and types of industrial users discharging
to the collection system, as well as the
size of the POTW. If additional
pretreatment controls or modifications
seemed unlikely to achieve the
pollutant reductions, then additional
treatment at the POTW was considered
the next most likely option.
Capital costs were estimated for
facilities where the analysis indicated
that additional or enhanced treatment
was needed. After identification .of ;the
treatment system, these costs were then
estimated based on the information from
such readily available EPA documents
, ,as the Development Document for \.
Effluent Limitations Guidelines and
Standards for the Metal Finishing Point
Source Category CEPA/440/1-83/091)
June 1983; Development Document for
Existing Source Pretreatment Standards
for the Electroplating Point Source
Category (EPA/440/1-79/003) August
1979; and Treatability Manual, Volume
IV: Cost Estimating (EPA/600/8-80-
042d) July 1980, which are available in
. the administrative record for this
rulemaking.
Effluent guidelines and development
documents appropriate to-each facility's
industrial category were also consulted.
However, since the majority of the
proposed Guidance pollutants of
concern were metals, EPA decided that
the metal finishing and electroplating
development documents were the most
appropriate for use in this study. Once
the estimates were made, they were
converted into first quarter,1992 dollars
using the Engineering News Record
Construction Cost Index.
For assessing annual costs associated\
with operation and maintenance of the
facilities, the analysis focused on the
costs associated with the addition of
supplemental treatment systems. These
costs were generally based on the same
information and sources as the capital
costs, and reconciled using the same
Engineering News Record Construction
Cost Index.
c. Monitoring Costs.. Monitoring costs
for permitted facilities were also
estimated. In those cases where
additional parameters and limitations,
were deemed necessary due to the
GLWQG, the monitoring regimes (i.e.,
sampling frequency) were established
consistent with the existing monitoring
' requirements for other parameters.
Monitoring costs were then estimated
based upon information generated hi the
development of the draft NPDES Permit
Application Form 2A. This information,
based on an evaluation of laboratories
for costs of over 60 established '
analytical methods, provides average '
costs per method for the more common
techniques.
As the discharge of bioaccumulative
.chemicals of concern (BCCs) are of
special concern under the proposed
Guidance, this study included
monitoring-only costs for Tier I BCGs for
all effected facilities regardless of
whether Tier I BCCs were detected or
expected to be present in a discharge.
These monitoring costs were estimated
using the same average analytical costs
described above for determining
compliance with effluent limitations.
Residual management costs were also
estimated for industrial and municipal.
facilities that were projected to install
end-of-pipe treatment and generate
additional sludge (e.g., chemical
precipitation). These disposal costs
were estimated for, each appropriate
facility in the sample and then -
extrapolated to derive total costs for all
facilities discharging to the Great Lakes
System.
A number of other costs were also
considered depending on the specific
circumstances surrounding a particular
type of facility. These were generally
one time costs related to pollutant, ,
minimization studies, bioconcentration
studies, whole effluent tbxicity testing,
pretreatmeht program revisions, waste
minimization audits, and implementing
pollution prevention techniques.
Generally these costs were included
with the capital cpstslbr purposes of
calculating annualized costs of
compliance,
5. Extrapolation of Total Compliance
Costs for Sample to the Great Lakes
Community pi Point Sources
Four different cost estimates were
developed to account for differences
between limits based on WLA #i (zero
background absent actual data) and
WLA #2 (assumed 50 percent
background absent actual data), as well
as the potential range of costs associated
with implementation of waste and •
pollutant minimization studies and
controls. These scenarios are described
below: •
Scenario 1: Limits basedon WLA #1
- and the low end of the estimated range
of waste minimization costs for all ,
facilities. , '
Scenario 2: Limits based on WLA #2,
the middle of the estimated range of
waste minimization costs for industrial
facilities, and PQTWs aggressively
implement the pretreatment program to
promote source control (high-end cost),
Scenario 3: Limits based on WLA #2,
the middle of the estimated range of
waste minimization costs for industrial
facilities, and POTWs install end-of-
pipe treatment. .
Scenario 4: Limits based on WLA #24
high-end of an- estimated range of waste
minimization costs, and POTWs install
end-of-pipe treatment.
The major difference between ' • .
Scenario 2 and Scenario 3 is the
emphasis on pollution prevention
versus end-of-pipe; Assumptions
underlying Scenario 2 emphasize
pollution prevention through source-
control. Scenario 3 focuses on end-of:
pipe treatment, especially at POTWs.
EPA believes that facilities will most
likely follow the pollution prevention"
approach to meet the requirements—
Scenario 2 will be the most likely
scenario of compliance. This approach
is also consistent with EPA's desire to
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
encourage pollution prevention as well
as the general preference of facilities to
reduce wastes first before considering
treatment.
To develop a single cost estimate for
each facility for each scenario described
above, the three cost categories
mentioned above were combined into a
single annualized cost, which reflects
the annual economic costs associated
with recurring activities, repaying
capital expenses, and special studies.
Annualized costs were calculated by
assuming that all capital costs and
special study costs would be paid by
borrowing money at an interest rate of •
seven percent and paying it back over a
10-year period. Annual costs of
monitoring, operation and maintenance
were added directly.
Given a single estimate of the
annualized cost for each facility, the
procedure for extrapolating costs from
the sample to the entire population is
pra-datermined by the stratified random
sampling procedure used to select the
subset of facilities examined hi detail.
Using the single annualized cost figure
lor each plant, an estimate of the cost for
each category/stratum was calculated by
averaging the values for individual
(sample) plants, and then multiplying
by the total (population) number of
plants in that category/stratum. The cost
estimate for the category is calculated
simply by summing over the strata in
the category. The cost estimate for the
entire universe of facilities is simply the
sum across categories. This procedure is
followed to estimate costs for each
scenario.
EPA has identified an estimated 3,500
indirect industrial dischargers that
discharge to POTWs in the Great Lakes
System and has developed preliminary •
"estimates of compliance costs for them.
These preliminary cost estimates are
based on the assumption that indirect
dischargers affected by the GLWQG
would incur the average cost that same
type of direct industrial dischargers
would incur under cost Scenario 2. In
addition, EPA assumed that costs to
categorical industrial users would be
higher than the costs to non-categorical
significant industrial users. The
following four scenarios for indirect
dischargers are consistent with the four
cost scenarios developed for direct
dischargers.
Scenario 1: Assumes that 10 percent
of all indirect dischargers in the Great
Lakes basin would install treatment
controls.
Scenario 2: Assumes that 30 percent
of all indirect dischargers in the Great
Lakes basin would install additional
controls
Scenario 3: Assumes that 20 percent
of all indirect dischargers would install
additional controls.
Scenario 4: Assumes that 20 percent
of all indirect dischargers would install
additional controls.
The estimated percent of indirect
dischargers affected by the Initiative
was based on an assessment of
conditions involving industrial users
arid their toxic dischargers to a
moderately large POTW in the Great
Lakes basin.
C. Limitations of the Analysis
1. Limitations in Scope
This analysis addresses costs to point
source dischargers and indirect
dischargers only. EPA did not attempt to
identify the least costly means of
controlling a particular pollutant or to
estimate costs to nonpoint sources. EPA
also did not attempt to estimate the
costs associated with other aspects of
the GLWQG, such possible future Tier I
numeric criteria and use of Tier n
values in individual permits, nor does it
quantify the incremental costs to States
of implementing the proposed
Guidance. Alternatively, the study does
not account for potential cost savings
from less stringent limits that could be
granted through the variance provisions.
It also does not attempt to estimate cost
reductions to direct and indirect
industrial and municipal dischargers
that are able to allocate part of the
burden of pollutant reduction to diffuse
sources under State nonpoint source
regulations.
2. Impact of Technical Assumptions
Based on the limited resources and
data available for this analysis, certain
simplifying assumptions were made that
could impact estimates of compliance
costs. Several of these assumptions and
their potential impact on the
compliance costs are summarized
below.
a. Due to the lack of effluent data,
process descriptions, etc., in some of the
permit files, as well as the constrained
analytical detection capabilities
reported by some facilities, it was
unclear if some of the pollutants of
interest were actually in the effluent at
detectable levels. If a facilities'
maximum observed values were at or
below detection levels, but the detection
limit was higher than what is achievable
using the most sensitive EPA-approved
analytical methods, then for purposes of
determining the need for WQBELs, the
value of the highest detection limit was
used as the maximum effluent
concentration. This would tend to '
overestimate the need to control toxic
discharges, and potentially overestimate
costs.
b. In the absence of any receiving
water critical low flow values, zero flow
was assumed (i.e., effluent dominated
flow). This most likely results in more
stringent WQBELs, and tends to
overestimate costs. Additionally, for
many facilities the 30Q5 and harmonic
mean flows were estimated from the
7Q10 low flow. Use of the actual 30Q5
and harmonic mean could result in
either less or more stringent limitations.
c. The most common program
component considered for this
evaluation for POTWs is development of
local limits for the pollutant(s) for
which WQBELs were established.
Estimation of local limit development
costs tend to overestimate compliance
costs, as the existing General'
Pretreatment Program regulations (40
CFR part 403) already require
pretreatment POTWs to evaluate the
need for new or revised local limits at
least every five years.
D. Findings
1. General Observations
a. The proposed Great Lakes water
quality criteria and values and
implementation procedures did not
always result in more stringent effluent
limitations for a particular pollutant, as
compared to existing permit limitations
and conditions or those limitations that
would be imposed as a result of current
regulatory requirements. This was
particularly true for the metals and
phenol for which either technology-
based and/or water quality-based
limitations were commonly found in
permits.
b. Some States appear to have
implemented controls more
aggressively. Therefore, permittees in
these States will incur proportionally
less compliance costs to comply with
the GLWQG.
c. Most of the data contained in -
permit files (e.g., the permit application)
and in PCS was not reported using
analytical methods sensitive enough to
accurately assess the true impact of the
GLWQG. This analysis tended to err on
the conservative side, as limits were
derived for pollutants that were
reported as below less stringent
detection levels. Permit writers could
require further analyses using more
stringent analytical methods to
determine whether a pollutant is indeed
present.
d. Where GLWQG-based limitations
were found to be more stringent than
the existing permit limitations, the
.incremental difference,was typically
.relatively small. Further, in the absence
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20987
of an existing permit limitation, the
incremental difference between the
GLWQG-based limitations and reported
concentrations was also found to be
relatively smalL Generally, on a
concentration basis, the incremental;
difference was found to be less than one
part per million (or one milligram per
liter). .,. '•'. :.
2, Specific Findings - r . V
a. Of the 3,795 direct discharging
facilities hi the Great Lakes System,
about 85 percent of these facilities are .
minor dischargers. POTWs account for
more-than-half (54 percent) of all major
dischargers.
b. Over 23 billion gallons per day
(total daily average) of wastewateris
discharged by major dischargers into the
Great Lakes System. The.steam electric
category alone accounts for over 70
percent of the total .daily average flow
discharged to the Great Lakes System.
Over 40 percent of all direct dischargers
are located in Michigan; over 20 percent
are located in Ohio. ' ...'-.
c. The total annualized compliance
costs of implementing the GLWQG to
" direct and indirect dischargers is
estimated to be between $80 million
under Scenario 1 and $505 million.
under Scenario 4 (See Table IX—1).
Major increases in costs between
Scenario 1 and Scenario 2 are attributed
to direct industrial and municipal
majors and to indirect dischargers as
POTWs implement aggressive source/
pretreatment programs; Under Scenario
3, costs to.major municipal facilities ,
more than double from Scenario 2 costs
as they-'are projected to install end-6f-
pipe treatment systems. These
additional treatment systems at POTWs
will substantially incfease.the residual
management costs—from about $5 . ,
million under Scenario 2 to.over $200
million under Scenario 3. Costs to ,,
mdirect dischargers decline under
Scenario 3 because POTWs are
installing .end-of-pipe treatment rather
than aggressively implementing the
pretreatment program. As a result, a
smaller number ofIndirect dischargers
are expected to incur costs. ;
TABLE IX-1—SUMMARY OF ANNUALIZED COSTS
- -• [First quarter 1992 $, millions]
; •-'•'.'• Cost categories "• . ' " -
, '-.-'' ' - • . ' . ; -.. _ ... -• • - *~_ • .
Major direct dischargers— Industrial
Major direct dischargers — Municipal '• ........ ....; ........
Indirect dischargers -.....; .—• — • •• • — ".—• •••—
Total costs , ;. .................
Scenarios
r',"'
: 37.4
5.1
10.5
26.5
79.5
2
, 61.1
41;,2
10:5
79.5
192.3
3
61.5
48.9
10.5
53.0
173.9
•«,',
88.5
53.5
10.5
53.0
205.5
Source: Assessment of Compliance Costs Resulting from Implementation of the Proposed Great Lakes Water Quality Guidance.
EPA considers Scenario 2 to be the
most likely scenario of the four
described above and estimates the '• :
annualized compliance cost to be about
$192 million. Indirect and direct major
industrial dischargers account for 41
percent and 32 percent, respectively, of
these costs. Major POTWs account for
the largest proportion of total
annualized costs borne by any of the
category of dischargers; the mining
category is estimated to incur the lowest
proportion .of costs for the universe of
industrial categories.
d. Major industrial and municipal
facilities would bear about 53 percent of
the total annualized costsjunder
Scenario 2 of the GLWQG. Indirect
dischargers account for about 41 percent
of the annualized costs. Minor
industrial and municipal dischargers
account for the remaining 6 percent of
the total annualized costs. Among the
majors, three categories account for the
majority (79 percent) of the costs:
POTWs (37 percent), organic chemicals/
refining (27 percent) and pulp and
paper (15 percent).
e. Average plant costs range from
. about $2,800 to $1,080,000. The three
highest average cost categories are
organic chemieayrefining ($1,080,000),
pulp and paper ($305,000), and .
miscellaneous; ($211,400); Although
major POTWs make up a large portion
of the total cost, the average cost per
plant is not among the .highest at
$130,400. .""--.'
About 3,200 minor dischargers or
small facih'ties incur an estimated $10.5
million in annualized costs for special .
monitoring studies. At 5 percent of the
total annualized costs, this translates
into less than $3,300 per facility.
f. Annualized capital costs account for
about 7 percent of the total annual cost
for majors, but none of the costs for
minors, which are not expected to
require investment in treatment "'
technology. , '
g. Waste/pollutant minimization
studies and implementation of
appropriate controls/techniques are a
very significant portion of the total
expected cost of the proposed Guidance.
The total annualized costs of such
studies make up about 54 percent of the
costs for direct dischargers under
Scenario 2.
h. The annual cost of monitoring,
operating and maintaining equipment, ".
etc., makes up about 36 percent of the
estimated annual costs for direct
dischargers. Special monitoring studies
account for about 4 percent. .
E. Provisions in the Proposed Guidance
Available for Use at States' Discretion
To Mitigate Compliance Costs
' The GLWQG includes several
provisions that States can use under
specified circumstances to allow
dischargers to lower their cost of
compliance. EPA has not projected the
.use of these variances in estimating .
costs. These are summarized below and
: discussed in more detail in their
respective sections;
1. Additional Tune To Collect Data To
Derive a Numeric Tier I Criteria or a
New Tier n Value
Procedure 9 of appendix F to part 132
(Compliance Schedules) provides for
States to grant dischargers time to
collect additional toxicity data to derive
aquatic life, wildlife, and human health
criteria or values. These additional data
could be used to develop new effluent
limits that may be less stringent and'
hence potentially less costly to comply
with. ; .'..'-.'..' ,
2. Variances From Water Quality
Standards '
*. Procedure 2 of appendix F to part 132
provides for States to grant WQS
variances if a discharger follows these
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20988 Federal Register / Vol. 58, No. 72 / Friday, April 16. 1993 / Proposed Rules
procedures. Such variances could result
in lower compliance costs.
3. Mixing Zones
Procedure 3 of appendix F to part 132
includes provisions regarding mixing
zones for point source dischargers.
Mixing zones generally allow less
stringent effluent limitations.
4. Reasonable Potential To Exceed
Water Quality
Procedure 5 of appendix F to part 132
provides procedures for determining
whether a discharge of a pollutant has
the reasonable potential to cause or
contribute to an exceedance of water
quality standards and, therefore, must
be controlled in the NPDES permit
through a WQBEL. Under procedures
discussed in appendix F, a permitting
authority may allow dischargers
additional time to derive numeric Tier
I criteria instead of Tier n values for
consideration in this determination and
thereby reduce the likelihood of a
finding of reasonable potential.
5. Designated Use Modification
The GLWQG provides methodologies
for deriving human health criteria based
upon (1) fish consumption and
recreational exposure, and (2) fish
consumption, recreational exposure and
drinking water consumption. A State
must provide protection based upon the
second category of human health
criteria for water bodies that are used as
public water supplies. The second
category of human health criteria are
generally more stringent than the first.
Water bodies may be designated as
public water supply. But if that use does
not exist, this designation may be
removed hi accordance with the
regulations at 40 CFR130. If the use is
removed, then the first set of criteria
would apply to the water body, and
would result in less stringent water
quality-based effluent limitations for
dischargers. These provisions are
discussed in more detail in section HE
of the preamble.
8. Site-specific Criteria
Procedure 1 of appendix F to part 132
provides for States to develop site-
specific modifications to aquatic life
criteria and values. These may result in
less stringent criteria or values, and ,
subsequent WQBELs, which may be less
costly to comply with.
7. Total Maximum Daily Load CTMDL)/
Waste Load Allocation (WLA)
Procedure 3 of appendix F to part 132
provides two options forTMDL
development. These options can be used
to pTov>da alternative control measures
for dischargers potentially subject to
water quality-based controls.
a. The State or Tribe may collect
sufficient data to support a smaller
margin of safety than would otherwise
be possible. This would allow
establishment of a larger WLA and
corresponding less stringent permit
limit.
b. The State or Tribe may also allocate
or reallocate the available load among
various point and nonpoint sources.
Such reallocations could be arranged at
the request of two or more sources who
may have reached an agreement
between themselves regarding a shifting
of the pollutant reduction burden. Such
reallocation could result in less
stringent effluent limits for some
dischargers.
8. Compliance Schedules
Procedure 9 of appendix F to part 132,
allows changes in schedules of
compliance for existing dischargers to
comply with new criteria and values.
Where limits are based on Tier n values,
such schedules may allow time to
collect data to revise such values before
compliance is required.
EPA has not attempted to project the
use of these provisions and, therefore,
has not estimated the potential savings
resulting from their application.
Commenters should address the
feasibility of using these and other
provisions and estimating potential
compliance cost savings attributable to
the future usage of these provisions.
F. Sensitivity Analyses
As described in section D.I above,
there were several limitations in the
scope of the cost study. In an effort to
evaluate the impacts of these study
limitations on the total estimated
compliance cost, several sensitivity
analyses were performed.
1. Tier I BCCs Are Found-
Bioaccumulating
As is required under the proposed
GLWQG implementation procedures,
when a water quality-based effluent
limitation (WQBEL) for a BCC is below
the most sensitive analytical detection
level, then a pollutant minimization
study and a bioaccumulation study
must be performed by the facility. For
purposes of the cost study, EPA
assumed that each of these studies
would be performed only during the
first year of the permit term; any future
costs related to the assessment and
control of Tier I BCCs found to be
bioaccumulating at unacceptable levels
were not estimated. If this situation
occurs, however, the proposed . :
Guidance requires the facility to review
and modify the pollutant minimization
study originally performed to control
the discharge of the BCC.
To address this issue EPA performed
several calculations to estimate the
potential incremental compliance cost.
These calculations were based on the
assumption that a facility would incur
the same pollutant minimization study
cost once more (including the Costs
associated with monitoring, performing
an initial assessment, and identification
and implementation of control
measures). It should be noted that
bioancumulation studies were required
, for only 20 of the 59 sample facilities
examined in the compliance cost study.
Incremental costs were calculated under
four different assumptions:
a. Assuming each of the permittees
required to perform bioaccumulation
studies find pollutants in the waste
stream which bioaccumulate;
b. Assuming 50 percent of the
permittees required to perform
bioaccumulation studies find pollutants
in the waste stream which
bioaccumulate;
c. Assuming 25 percent of the
permittees required to perform
bioaccumulation studies find pollutants
bioaccumulating! and
d. Assuming 10 percent of the
permittees required to perform
bioaccumulation studies find pollutants
bioaccumulating.
To calculate a total incremental cost,
' EPA extrapolated to the universe of
direct dischargers in the Great Lakes
System utilizing the same procedures
used to calculate the total compliance
cost in the cost study.
Using this procedure, the incremental
costs under the most conservative
assumption (i.e., assuming 100 percent
of the facilities required to perform • •
bioaccumulation studies would require
additional controls) range from about
$10 million to $52 million under the
four cost scenarios. Under the least
conservative assumption (i.e., assuming
10 percent of the facilities required to
perform bioaccumulation studies would
require additional controls) incremental
costs range from about $1 million to $5
million under the four cost scenarios.
EPA believes that the most
conservative assumption (i.e., 100
percent failure) is unlikely to occur; the
most likely incremental cost that would
be incurred would be between the costs
associated with 50 and 10 percent
assumptions. Assuming that 25 percent
is considered the most likely failure
rate, and if cost scenario 2 is considered
the most likely compliance cost estimate
for the GLWQG, then the total
incremental cost related to failure of
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
20989
.bioaccumulation studies would be about
$5.0 million dollars annually.
2. Proposed Antidegradation , . L
Requirements
The baseline cost study did not
. address costs associated with the .
proposed antidegradation requirements.
EPA developed preliminary cost ,
estimates of the proposed GLWQG :
antidegradation policy upon the
• regulated community of the Great Lakes
System. This preliminary analysis is .
based on the assumption that of the
existing 3,795 permittees that will be. ,
affected by the GLWQG, approximately
190 (5 percent) are expected to request
an increase in permit limitations during
a five-year permit cycle. For.purposes of
this; apalysis, it is also assumed that
certain new facilities will propose to
initiate direct discharge and request to
lower the water quality. Therefore, an
additional 3 .percent of the existing
minor facilities (3j>ercent of 3,207, or
96 facilities) and I percent of the
existing major facilities (l percent of
588, or 6 facilities) were assumed to .
represent hew dischargers that choose to
prepare antidegradation demonstrations,
• again, during a five year permit cycle. In
summary, a total of ,8 percent (for minor
facilities) and 6 percent (for major
facilities) of the total number of
facilities in each category and flow
strata were assumed for this analysis. "•
Based on the above assumptions for
the number of affected facilities and the
results from the .cost study, preliminary
cost estimates for demonstrating the
rieed for antidegradation were
developed. To perform the preliminary
analysis, the cost,of implementing the
results of each 6f the steps required for
an antidegradation demonstration were
developed separately (i.e., Step 1—
pollution prevention, Step 2— •
alternative or enhanced treatment, Step
3—social/economic analysis).
a. Step 1—Pollution Prevention,The
first step a facility must undertake to
support a determination for the need for
degradation or a justification for the
heed to lower water quality is to show
that implementing pollution prevention
measures will not result in compliance
with the existing effluent limits. The
costs for assessing and implementing
waste minimization/pollution
prevention measures were derived from
estimates contained in the GLWQG cost
study. Each of these costs were then
multiplied by 8 percent (for minor .'
facilities) and' 6 percent (for major
facilities) of the total number of
, facilities in each category and flow
strata and totalled. • ' '
Assuming that all facilities
performing-the Step 1 demonstration
conclude that implementation of •
pollution prevention will result in
compliance with their existing effluent
limits, the annualized compliance costs
could range from about $2,7 million
(under cost scenario 1) to $6.7 million
(under cost scenario 4). -.-"..'- r
b. Step 2—Alternative or Enhanced
Treatment. Assuming that all of the
facilities performing a Step 1 analysis
demonstrate that pollution prevention
measures will not eliminate the need to
significantly lower the water quality,
then all of the assumed facilities would
move on to a Step 2 analysis (assuming
'. there is still a desire by all facilities to
pursue significant lowering of the water
quality). To assess the costs of -;
alternative or enhanced treatment, three
different costs were estimated including
the additional costs to modify-the
existing treatment train at a facility, the
costs for additional treatment, and
reporting costs. These three cost
estimates were totalled and then
multiplied by 8 percent (for minor
^facilities) and 6 percent (formajor
facilities) of the total number of
facilities in each category and totalled.
If all assumed existing and new
facilities were required to spend up to
10 percent of average capital, and
Operating and maintenance costs more
than the treatment required to meet
relaxed effluent limits, then-these
additional annualized costs could range
from about $300,000 (under scenario 1).
to about $724,000 (under scenarios 3 '>
and 4). It is important to recognize that
if these costs are incurred, the
antidegradation procedures would not
require the entity to go to Step 3 and
none of the costs associated with Step
3 would be incurred.
c. Step 3—Social/Economic Impact. -
To estimate costs for Step 3 it was
assumed that all facilities performing a' :
Tier 1 and Tier 2 analysis are denied
their request to lower the water quality
(i.e., the facilities did not adequately
justify the case for the social or
economic benefits of lowering the water
quality associated with the proposed
action and therefore the facilities must
incur the costs associated-with treating
effluent to current water quality based
effluent limits or loading rates). This '
, scenario ,is assumed to be conservative
as it would be expected that many
facilities would adequately'show that
lowering the water quality would result.
in social or economic benefit. For
analysis of Step 3 costs it was assumed
that each facility would incur the
following costs to prevent the •'-••••
significant lowering of the water quality:
the .additional costs to modify the :
existing treatment train at a facility, the
costs for additional treatment; and the •
costs to perform the social arid \.
economic analysis. These-three cost
estimates were totalled and then ,
multiplied by 8 percent (for minor'
facilities) and 6 percent (for major .
facilities) of the total number of
facilities in each category and totalled.
Estimated annualized costs for Step 3
range from about $i.5'million (under
scenario 1) to $3.6 million (under
scenarios 3 and 4)t EPA considers these
costs to be overstated since some ,
pollutant reduction benefits from
implementation of pollution prevention
alternatives identified in Step 1 will be
realized, by facilities.
d. Summary. In summary, under the
worst case/the proposed GLWQG anti-
degradation procedures could cost the
regulated community in the Great Lakes
basin approximately $11 million per
year. This estimate should be viewed as
an overestimate due to the fact'that it is
highly unlikely that a facility will incur
the total cost for each step in the
demonstration process (i.e., there will
be some treatment benefit at the
completion of steps 1 and 2 of the
demonstration process). In addition, •
some facilities may be allowed to lower
the water quality if social and economic
impacts are demonstrated, and thus the
facilities would not be required to incur
all the costs for additional treatment.
Assuming that Cost Scenario 2 is the
most probable cost scenario, then the
more •reasonable worst case,costs related
to the proposed GLWQG anti- _..: ,
degradation procedures swtould be about
$7 million dollars.
3. Future Detection of BCCs '>
•. Preliminary estimates were derived to
reflect the potential incremental costs to
direct dischargers to the waters of the
. Great Lakes System if BCCs for which
Tier ! criteria are proposed in Tables 1
through 4 of Part 132 are detected from
increased monitoring. In accordance
with the proposed GLWQI
implementation procedures, a facility is
required to conduct a pollutant
minimization study and a
bioconcentration study if a water
quality-based effluent limitation
(WQBEL) for a Tier IBCC is set below
analytical detection levels. Based on
these requirements, 20. of the 59 ;
facilities evaluated in the cost study
would be required t6 undertake a , , \
pollutant minimization arid a
bioconcentration study, ^incathe cost
study included costs for all facilities to
monitor for Tier I BGCs, an analysis was
conducted to determine what the
incremental-increase in pollutant
minimization and bioconcentration
study costs might be if Tier I BCCs are ;
detected in the discharge. A simple set
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2099'
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
of assumptions was used to estimate the
possible incremental pollutant
minimization andbioconcentration *
study exists for the entira population
resulting from increased Tier IBCC
monitoring. These assumptions include:
each facility in the population is
expected to detect, at most, one of the
11 Tier I BCCsj and 25 percent of the
facilities in the population are expected
to detect one Tier I BCC. The costs to
perform the pollutant minimization
study and the bioconcentrau'on study
wore estimated using the same
procedures and cost assumptions used
in the cost study analysis—excluding
monitoring costs.
The resulting total incremental
anmudized costs are estimated to range
from $13.4 million (under Cost Scenario
l) to $37.3 million (under Scenario 4).
Assuming that Cost Scenario 2 is the
most likely scenario, then the estimated
incremental cost is $27.8 million
annually. It should ba noted that the
cost contribution by minors account for
more than 50 percent of the additional
cost. Because minors generally do not
have toxics in their discharge, they are
not expected to detect any Tier I BCCs
in their discharge. Thus, the additional
costs are perceived to be overestimates.
4. Elimination of Mixing Zones for BCCs
The proposed GLWQG
implementation procedures require that
within 10 years after the effective date
of the regulation, waste load allocations
(WLAs) for BCCs be set to the most
stringent water quality criterion or a
fraction of the WLA that has been
established (i.e., no mixing zones will
be allowed). EPA assessed the potential
costs resulting from future elimination
of mixing zones for BCCs for facilities
that were evaluated hi the cost study.
To assess this future impact, EPA
compared the existing most stringent
GLWQG-based WQBEL with the most
stringent water quality criterion for the
20 of 59 facilities required to comply
with Tier I BCC VVQBELs. Presumably,
if some or all of these 20 facilities have
to comply with a more stringent -
Hinitation(s) (i.e., water quality criteria)
in 10 years, than they will incur costs
beyond what was estimated in the
compliance cost study. EPA also
presupposed that the results derived
from the evaluation of these 20 facilities
would be a good general indication on
the likely impact on the entire
population of dischargers. The results of
this comparison are provided below:
a. Fifteen facilities had existing
WQBELs for Tier I BCCs that were equal
to the most stringent proposed numeric
water quality criteria. In addition, both
tha WQBEL and the water quality
criteria were below tha most sensitive
detection levels by at least one order of
magnitude. Thus, these facilities, as
evaluated under all of the assumptions
in the compliance cost study, would not
be expected to incur, any additional
, costs because elimination would not
require further reductions.
b. For seven facilities, proposed water
quality criteria were more stringent than
the WQBELs. These facilities would
appear to be candidates for incurring
additional compliance costs 10 years
from the effective date of the regulation.
, For facilities listed in this finding,
however, the WQBEL was at least one
order of magnitude less than currently
achievable detection levels (and
consequently the water quality criteria
was even further below detection
levels). While in theory, one can assume
that a water quality criterion, by virtue
of its being less than the WQBEL, will
result in additional costs and/or impacts
for facilities, a practical justification
appears difficult—unless the detection
limit for each Tier I BCC in this category
can be lowered by the time compliance
with water quality criteria are required
(10 years). Thus, because of the inability
to predict where the detection limit
might lie in 10 years, the prediction of
future costs has no basis at this time for
facilities in this finding.
c. For two facilities, only one Tier I
BCC (endrin) had a detection level that
was lower than both the WQBEL and
the water quality criteria; In these cases,
it was determined that the WQBEL and
the water quality criteria were in the
range where costs associated with
compliance with both requirements can
be anticipated. But both of these
facilities had existing permit limits for
endrin that are more stringent than the
calculated WQBEL. Thus, the existing
permit limit was compared to the most
stringent proposed water quality
criteria. In both cases, the permit limit
is very close to the proposed water
quality criteria implying that any future
compliance costs would be minimal.
Further, these facilities were already
projected to incur costs for the control
of other pesticides for which GLWQG-
based effluent limits were established.
Based on this, EPA believes that future
compliance costs for endrin are
negligible for both of these facilities.
Also, one of the two facilities had a
WQBEL for heptachlor that was greater
than the detection level. The most
stringent water quality criteria,
however, was below the most sensitive
detection level by one order of
magnitude. For the same reasons .
discussed for endrin, the cost impact is
expected to be minimal.
d. In summary, EPA's conclusions,
based on an evaluation of the 20
facilities on the future impact of the
elimination of mixing zones are:
i. The current compliance cost
estimate appears to have indirectly
taken into consideration the impact of
end-of-pipa requirements for Tier I
BCCs for the majority of facilities in the
sample. Generally, the population of
dischargers is likely to exhibit the same
characteristics. For these facilities, no
future impacts are anticipated.
ii. Since changes in analytical
detection levels cannot be predicted
and/or are unlikely, facilities.that have
a more stringent water quality criteria
than a WQBEL, on a practical basis, are
the same as the facilities where the -
WQBEL and the water quality criteria
are the same.
iii. Assuming that no significant
changes in analytical detection levels
occur over time, only two Tier I BCCs
(endrin and heptachlor) are expected to
cause additional costs from end-of-pipe
requirements for a very small portion of
the sample (2 facilities). These costs are
expected to not be significant.
5. Prevalence of Tier II BCCs and
Potential BCCs
Since the cost study focused only on
pollutants with proposed Tier I numeric
criteria, the estimated compliance costs
reflect only those costs associated with
complying with water quality-based
effluent limitations (WQBELs) for Tier I
BCCs. Acknowledging that there may be
future costs associated with regulating
additional BCCs and potential BCCs
using Tier II values, EPA evaluated how
prevalent such Tier n BCCs and
potential BCCs were in the discharges of
the 59 facilities examined for the cost
study. Using the results of this
evaluation, some general conclusions
were drawn on what the cost impact
might be if facilities are required to
comply with future Tier n BCC and
potential BCC requirements. The two-
tiered approach is discussed in more
detail in section II.D.
To evaluate Tier II BCCs and potential
BCCs, EPA re-examined the files of the -
59 sample facilities considered in the
compliance cost study. Permit
application data and any other data in
the permit file were reviewed to
determine if any Tier n BCCs and
potential BCCs were pervasive in the
facilities' effluent. As part of the
evaluation EPA also examined each •
facility's existing permit to determine if
any Tier H BCCs and potential BGCs are
currently regulated (i.e., limited and/or
monitoring requirements). The findings
indicate that:
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20991
a. A total of 28 out of 50 facilities had
monitoring data that ranged from a few
(5) to most (27) of the 32 Tier II BCCs.
(Nine of the 59 in the sample belong to
the two minor categories. None of the
minor facilities had analytical data for
the Tier II BCCs and potential BCCs.
Thus, only the results of facilities in the
major categories (50) are reported.) Out
of these 28 facilities, only two facilities,
detected a Tier II BCC. Moreover, these
facilities detected only two of the 17
Tier II BCCs. These facilities detected
one potential BCC each; and only 2 of
the 15 Tier H potential BCCs.
b. Sixteen of the 50 facilities did not
provide any monitoring data (the ;
majority of which fall into the major
POTW category).
c. Nine of the 50 facilities did not
provide any monitoring data but
reported that the BCCs were "believed
absent for some or most of the Tier n
BCCs and potential BCCs.
d. The detection levels reported for
virtually all Tier II BCCs and potential
BCCs were higher than the most .
.sensitive currently achievable detection
', levels. '•'.'•.' :
e. The concentrations of Tier II BCCs
and potential BCCs detected were ' •
generally less than current Federal
water quality criteria. .. ' " "
f., Twelve of the 50 facilities had
monitoring or other permit conditions,
for several of the Tier II BCCs and
potential BCCs.
In summary, if water quality criteria
are developed for Tier II BCCs and
potentialBCCs under the GLWQI and
these criteria become permit
requirements, the increase in
compliance costs for additional
treatment and/or .control costs is not,
expected to be significant. This-
preliminary conclusion is, based on the
fact that several Tier.II BCCs and •
potential BCCs are already regulated in
permits for 12 of the sample facilities,
.as well as the fact that, based on '
discharge data reported by sample
facilities, Tier n BCCs and potential
BCCs were not often detected by the •
sample facilities in their effluent
streams^ It should be noted that EPA is
aware that a key consideration regarding
.the available data is that the currently
reported detection levels may be
masking the presence of some Tier II
BCCs and potential BCCs present in
lower concentrations. This preliminary
conclusion is also underscored by the
fact that the presence of a water quality
criteria or value for a BCC (or any :
pollutant) does not explicitly mean that
a facility will incur any additional
compliance costs. Even if a water
quality Criterion or value has been
developed, it may be highly unlikely
that the BCC is actually present (at least
for most of the industrial categories), so
nacompliance costs (other than
monitoring) wpuld be borne by the
facility. , , ,
6. Evaluation of Intake Pollutant
Options ,
The proposed GLWQG
implementation procedures at
procedure 5.E of appendix F of the
preamble provide a proposed
mechanism for permitting authorities to
consider the presence of intake water
pollutants in a facility's discharge when
.determining the necessity for WQBELs,
Procedure 5.E of appendix F would
allow the permitting authority to
determine that the return of identified
intake water pollutants to the same body
of water under specified circumstances
does not have the reasonable potential'.
to cause or contribute to an exceedance
of water quality .standards. Based on this
determination, the permitting authority
would not be required to establish
WQBELs for the identified intake water
-pollutants. This procedure would apply
to facilities that-return unaltered intake
water pollutants to the same .body of
water without increasing the mass .
loading rate or concentration of the .
pollutant at the edge of any available
mixing zone, and that do not discharge.
the intake water pollutants at a time or
location that would cause adverse water
quality effects to occur that would not
-have occurred if the pollutants were left
in place. EPA compared the cost study
assumptions and methodologies to the
options presented in the proposed
regulation in an attempt to evaluate the
associated compliance cost
implications, '
As previously described in section .
I.B.2 of this preamble, for the purpose
of the cost study, EPA chose to handle
pollutants in intake water in several
ways in the cost study. First," WQBELs
were not calculated for outfalls that
contained uncontaminated non-contact
cooling water that was'-withdrawn from
the same water body to which it was
discharged. This is consistent with the
proposed Guidance in procedure 5.E'of
appendix F where a regulatory authority
could determine that there is no
reasonable potential to exceed'a Tier I
criterion or Tier II value if certain
conditions are met. EPA believes that
most uncontaminated once-through
non-contact cooling water would meet
these conditions. In addition, to
evaluate the costs associated with other
options for addressing intake water
pollutants where the pollutant
" concentrations exceed Tier I criteria or
Tier H values, the WQBELs were
calculated in two different scenarios: "
a. WQ3EL Scenario #1: WQBELs were
set to the intake water column
concentration regardless of the source of
the intake water..
b. WQBEL Scenario #2: WQBELs were
set equal to the most stringent criterion
regardless of the source of the intake
water. • . ' .,. .' -••'"' . '
Because the cost study used an
approach that combined provisions of
' several of the intake credit options
presented in this preamble, no direct
comparison was possible between the :.
cost study estimates and the total costs
related to the proposed options for
allowing intake credits. However, the
methods used to address instances,,
where the intake water concentrations
exceeded Tier I criteria and Tier H
values and the resulting compliance .
cost estimates appear to bracket the total
costs of each of the intake credit
options, with the exception of the
proppsed Guidance and alternative
Option 1. - ,
Proposed procedure 5 .E of appendix F
. is likely to have its greatest-application .
with cleaner discharges such as once-"
through non-contact cooling water. For
this reason, the rationale discussed
above, for excluding non-contact cooling
water from cost consideration is"
, somewhat consistent with the proposed
Guidance, It is possible-that some non- ...
cooling water dischargers that were not .
excluded from the eost evaluation
. would also meet the conditions . - , ' ,
necessary for'a permitting authority to
determine that there is no reasonable • •
potential to exceed a Tier I criterion or '
Tier n value. The impact of this
potential on cost estimate cannot be
accurately predicted because the permit
file information is insufficient to .
determine whether each of these
facilities meet the five conditions
associated with proposed procedure 5.E
of appendix F. •
Under the remaining alternative
options for addressing intake water
pollutants, depending on whether the
WQBEL is set equal to the receiving
water concentration, the water quality
criterion (WQC) or at an alternate level,
the cost study WQBEL #1 and WQBEL
#2 scenarios may or may not be
consistent. Generally, estimated costs to
comply with the WQBEL #1 scenario
may reflect the costs associated with the
alternative options that may potentially
-result in establishment of WQBELs
equal to the background or intake
pollutant concentration (i.e., portions of
Options 2, 3, and 4).
Alternatively, costs to comply with
the WQBEL #2 scenario may reflect the
costs associated with the alternative
options that result in establishment of
WQBELs at the lowest water quality
-------
20092
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
standard or criterion (i.e., Option 4b).
The estimated cost to comply with
WQBEL #1 scenario is represented by
Cost Scenario 1 ($56.7 million per year
for direct dischargers). The estimated
costs to comply with WQBEL #2
scenario is represented by Cost
Scenarios 2,3, and 4 (ranging from
$112.8 million to $452.4 million per
ytwr).
Assuming Scenario 2 is the most
likely of the costs associated with
complying with the WQBEL #2 scenario,
then tho potential costs associated with
the options addressing intake water
pollutants generally range from $52.9
million to $112.8 million per year. For
a given option, the actual total costs
would realistically tend to move toward
tho lower end of the range because (l)
if more pollutant data was available,
more situations where the intake water
pollutants exceed Tier I criteria and Tier
II values may be revealed, resulting in
potentially greater application of the
pftjpossd Guidance; and (2) the
compliance costs for all options except
1 and the proposed Guidance do not
include any cost reductions that would
result from application of phased
TMDLs, variances or specific
modifications to criteria. The extent of
such cost reductions cannot be
estimated because of the site-specific
nature of such allowances data
limitation.
Alternatively, if existing mechanisms
(o,g,, variances and phased TMDLs, and
site-specific criteria modification) are
not utilized by a regulatory authority,
the potential compliance costs may
increase. .
7. Summary
Sensitivity analyses of major cost
study technical assumptions were
performed to determine the potential
impact on the total estimated
compliance cost attributable to the
proposed Guidance. Table IX—2
summarizes the results of these
analyses.
TABLE IX-2—SUMMARY OF OTHER POTEN-
TIAL COMPLIANCE COSTS" NOT AD-
DRESSED IN THE GLWQG COST STUDY
TABLE IX-2—SUMMARY OF OTHER POTEN-
TIAL COMPLIANCE COSTS NOT AD-
DRESSED IN THE GLWQG COST
STUDY—Continued
Original Cost Study Estl-
ma:a,
1. Costs if Tier I BCCs are
Found BtoaccumuJatlng.
2. Costs Related to Pro-
posed AnU-Dogradatfon
Requframants.
3. Costs Related to Future
Detection of Tier I BCCs.
Annualized
costs (first
quarter 1992 $,
millions)
192.3
5.0
7.0
27.8
4. Costs Related to Elimi-
nation of Mixing Zones for
BCCs.
5. Costs Related to Preva-
lence of Tier II BCCs.
6. Costs Related to Intake
Credit Options.
Annualized
costs (first
quarter 1992 $,
millions)
Unknown—In-
•crease ex-
pected to not
be signifi-
cant
Unknown—In-
crease ex-
pected to not
be signifi-
cant.
Unknown—Can
result in ei-
ther cost sav-
ings or addi-
tional costs.
Note: All costs reflect.Cost Scenario 2. • •
Source: Assessment of Compliance Costs
Resulting from Implementation of the
Proposed Great Lakes Water Quality
Guidance.
Based oa the sensitivity analyses
performed, and as summarized in Table
IX-2 above, an additional $40 million
annually in costs may also be
attributable to the proposed Guidance.
This incremental cost represents about a
21 percent increase above the cost study
estimate. If added to the most likely cost
study estimate (i.e., Cost Scenario 2), the
total compliance costs could reach as
high as $232 million annually.
G. Future Analyses
In addition to refining the cost
estimates for the RIA that EPA will
prepare as part of the final rulemaking,
several other analyses will be
performed. EPA will assess the
economic impact of the estimated costs
on both industrial dischargers and
municipal facilities, including an
assessment of the impacts on small
businesses. The results of these analyses
will be placed in the record for this
rulemaking.
The final EPA analysis will include
an economic assessment of various
options that are available to implement
the final Guidance, the effect of the final
Guidance on State implementation
policies, especially for facilities that are
not discharging to the waters of the
Great Lakes System, policy implications
of implementing the proposed Guidance
in States not part of the Great Lakes
System, and the relevant contributions
of other sources of pollution to the
waters of the Great Lakes System, EPA
will also assess the potential for using
market-based incentives (e.g., effluent
trading between point and nonpoint'
sources) that can be used to achieve
compliance with the requirements of the
proposed Guidance.
H. Cost-effectiveness
1. Introduction
Cost-effectiveness values can be used
to compare the efficiency of,one
regulatory option in removing
pollutants to another regulatory option.
Cost-effectiveness is defined as the
incremental (to another option or to a
benchmark, such as existing treatment)
annualized costs of a pollution control
option per incremental pollutant
removal (measured in copper-based
pounds equivalent). In other words, ths
cost-effectiveness value represents the
unit cost of removing the next pound-
equivalent of pollutant.
The cost-effectiveness analysis is a
useful tool for evaluating regulatory
options for the removal of toxic
pollutants. A cost-effectiveness
calculation is simply a ratio of the
annualized costs of a control option for
a group of dischargers to the pollutant ,
loadings removed from surface waters
by that option. Three factors are of
particular importance in the cost-
effectiveness calculations. First, the
analysis is based on removals of
pounds-equivalent—a term used to
describe a pound of a pollutant
weighted for its toxicity. Usa of pound-
equivalent values reflects the fact that
some pollutants are more toxic than
others and enables removals to be
summed across pollutants. Copper is
used as the standard pollutant for
developing toxic weighting factors.
Second, where there are a number of
control options being evaluated, the
analysis is often done on an incremental
basis—using the incremental cost and
removals of one control option
compared to another option or to
existing treatment. Third, cost-
effectiveness values are considered high
or low only within a given context, such
as similar discharge status or for
comparison with other industries.
2. Pollutant Loadings Reductions
Pollutant loadings reductions were
estimated to indicate the decrease in
pollutants discharged due to more
stringent GLWQG limits. Baseline
loadings were determined in pounds per
day by multiplying the permit limit or
effluent concentration by the facility's
flow rate and a conversion factor. If
either the permit limit or effluent
concentration for a pollutant was
reported as less than a detectable level,
the reported detection level was divided
in half. Using extrapolation procedures
-------
Federal Register /Vol. 58, No. 72 /Friday, April 16, 1993 / Proposed Rules
20993
similar to those used for compliance"
costs, sample facility baseline loadings
were averaged across all facilities in
each strata, multiplied by the total
number of facilities in each strata, and
summed. Total baseline loadings for
each pollutant for all direct discharging
facilities are shown in Table IX-3 under
baseline,
TABLE IX-3.— POLLUTANT LOAPJNG REDUCTIONS
ILbs/day]
Pollutants
Arsenic ,.... .'. ,..„."....„.... .
Cadmium .....: '.„
Chlorobenzene
Chromium III .-. „
Chromium VI ,
Copper .'. .......,.';....i.
Cyanide total ..............;
4,4'DDT ; ,
Dieldrin .;....... .
2,4-Dimethylphenol , , .....1
2,4-DInitrophenol .*.. ...., ,
Endrin „
Heptachlor
Hexachloroethane .'. ....'...„•
Lindane ..„.. .".
Mercury „... :.....
Methylene Chloride
Nickel
Parathlon .'......i. ,....;
PCBs i....... .
Pentachlorophenol
Selenium IV .•
Selenium VI
Selenium, total .
2,3,7,8-TCDD
Toluene
Toxaphene „
Zinc .', .....................
Totals..... ;
Baseline
5356
•000
5,760.89
1 17
000
3.38
1533
78,598.67
7731
009
032
0 15
000
000
000
037
1 50
000
0 00
5658
000
8 659 86
000
3 16
6 84
000
0 00
0 00
911.50
00059
067
640
27 17
9,225.14
103,410.07
Scenario 1
reduction
1 10
000
5,367.95
043
0 00
0.00
944
75 664 12
3284
000
000
0 10
000
000
000
0 11
0 17
0 00
000
3879
000
8027
000
0 ?3
1 09
000
000
000
903.51
00056
•0 00
0 05
26 1 1
1,017.05
83,143.88
Scenario 1
percentage
•change
2
• • 0
"93
36
o
0
62
96
42
o
16
66
0
0
0
29
11
0
0
'68
0
•1
o
7
16
0
'- 0
99
95
n
•j
96
»p
80
Scenario 2
reduction
1 01
' o 00
5 622 53
: 0 BO
000
000
76 292 93
34 <}3
000
000
0 10
000
000
o no
0 21
017
o no
o no
45 BQ
0 00
9278
6 "00
2 02
000
000
0 00
90377
• 00056
000
"005
' OR 44
1,048.61
84,082.98
Scenario 2
percentage
change
98
Rfl
0
> RQ
97
AK
0"
fiflF
0'
11
A
0"
0'"
•i
0
•IO
0
99
0
•i
QR
11
81
Note: Numbers may not add due to rounding. . . :
Source: Assessment of Compliancs Costs Resulting from Implementation of the Proposed Great Lakes Water Quality Guidance.
Scenario 1 (reflecting WQBEL #1) and
Scenario 2 (reflecting WQBEL #2) ;
loading reductions were calculated by
finding the difference between the
esdsting permit limits and the GLWQG
limit for each pollutant. The resulting
difference was converted to pounds per
day by multiplying the difference by the
facility's flow rate and a conversion
factor. Several assumptions were made
to calculate the loading reduction for a
.pollutant:
a. If the difference between the
GLWQG-water quality-based effluent
, limitation (WQBEL) and the highest
reported concentration was negative,
zero reduction was assumed. This .
situation occurred because there were
instances where the reported
concentration was below the GLWQG
WQBEL. -
b. When the highest reported
concentration was reported as below a
detection level, one-half of this level
was used as the baseline concentration.
c. If GLWQG WQBEL was below
analytical detection levels, the
limitation was set equal to.the detection
level divided by two for purposes of
calculating a difference.
d. It was assumed that facilities are
discharging at the level of the existing
permit limitation.
Loading reductions were calculated
for each direct discharging facility in the
sample and then extrapolated to .all
direct discharging facilities in the Great
Lakes System (costs and pounds
removed from indirect dischargers are
excluded from these calculations).
These are also shown in Table IX-3.
As shown in Table IX-3, Scenarios 1"
and 2 reduce the loadings of toxic .
pounds by about 80 percent. In general,
metals are reduced by a much higher
percent than the organic pollutants.
3. Toxicity-Weighted Loadings
Reduction
, .The pollutant loading reductions from
direct dischargers were weighted to
compare to national standards using
EPA toxic weights (EPA/C3ST1988 Cost
Effectiveness Criteria and Weights).
Toxic weighting factors are derived
primarily from chronic freshwater
criteria and toxicity values. However,
-------
20994
FederalRegister /Vol. 58, No. 72 /Friday, April 16, 1993 / Proposed Rules
both human and aquatic criteria are
used In cases where a human health
criterion has been established for the
consumption offish. Toxic weights
along with toxicity-weighted pounds are
shown in Table DC—4 as are the
reductions associated with Scenarios 1
and 2.
TABLE IX-4.—POUND-EQUIVALENT LOADINQ^REDUCTIONS
(Ibs-equlvalerit/day] .' '.' •'.
Pollutants
AfsanJc „„ .. . .
Bartzeno „.
Cadmium
CWordarw ..„„.....„
CWorobonzena
Chromium III , , ,
Chromium VI ..
Coppar ,„. . . .
Cyanfdo, fraa
Cyanide, total
4.4T3OT
DfaWrfn .11.
2,4*Dlmethy!ph«nol
2,4-Dinttroph«noi
Endrln v
HapiacWor
Haxachtorobonzona
HoxacWoroelhana
Undana .,...,
M«rcury
Mathyfana Chloride
Nfckel
Parathton ..,
PCBs
Pantachiorophenol .,
phono!
Sfteflkim IV
Selenium VI - .
Selonlum, total .,
2,3,7,8-TCDD
Totoona ,....„„„„
Toxaphsno
TrfchlofoeU^fefM}
Totals
Toxic weights
3203
003
509
246899
000
0.02
3550
046
1 07
1 07
28,933.33
1031578
0.00
0.18
243684
3 404.71
756.80
007
7896
50502
003
009
430.76
7,488.60
043
000
0.16
0 16
" 016
40 005 600 00
000
2876712
000
005
Baseline
pounds equiva-
lent
1 715 53
000
29 322 96
288077
000
009
54429
36 682 00
8326
0 10
9,336.58
1 599 1 1
000
000
000
1 262 56
1 131 97
000
0 00
28 573 71
000
78805
0.00
23 681 .45
295
000
0.00
000
146 12
23 532 48
000
184 160 89
026
470 48
345,915.60
Scenario 1 re-
duction pounds
equivalent
35 08
000
27 322 89
1 053 17
000
000
33524
35 312 45
3537
000
150.34
1 053 24
0 00
000
000
36206
131 04
000
0 00
1958940
000
730
000
1 701 98
047
000
000
0 00
14484
22 450 43
0 00
1 567 12
024
51 87
111,304.55
Scenario '
percent
change
0
93
00
37
o
o
62
QR
42
o
1 6
66
0
o
o
29
11
o
o
68
•)
o
0
7
16
0
0
o
99
95
0
1
96
11
32
Scenario 2 re-
duction pounds
equivalent
oc no
0 00
28 61868
1 flfifi fin
0 00
000
375 70
oc enc OH
37 R1
0 00
15034
1 ns^ 94
0 00
0 00
0 00
721 95
131 04
000
nnn
23 174 89
n nn
B44
000
3 047 29
0 87
0 00
000
n no
14488
y> 4sn 43
• 0 00
1 *ifi7 19
025
5348
119,143.84
Scenario 2
percent
change
t n
qfl
CO
0'
fiq
Q7
A%
1 6
CG
o
o
57
11
31
1
o
13
90
o
qq
q*;
n
flfi
'11
34
Note: Numbore may not add due to rounding.
Sourot; Assessment of Compliance Costs Resulting from Implementation of the Proposed Great Lakes Water Quality Guidance.
The proposed Guidance would reduce
the toxicity-weighted pounds, or
pounds-equivalent, by about 32 percent
under Scenario 1 and by about 34
porcent under Scenario 2,
4. Cost-effectiveness
Tha cost-effcctivonoss values are
calculated by multiplying the pounds-
equivalent per day, shown in Table K-
4, with 365 days to derive total annual
pounds-equivalent reduced under each
scenario. Total annualized costs for
direct dischargers in each scenario are
then di^fidud by total annual pounds-
equivalent for each scenario to estimate
tho S/lb-eq. for each scenario. The cost-
ef&ctiveness of all four cost scenarios
ranges from $1.30 per pound-equivalent
to $10 40 per pound-equivalent over the
baseline; the cost-effectiveness of the
most likely scenario is $2.60 per pound-
equivalent. The costs for and pounds-
equivalent removed from indirect
dischargers are not included in these
calculations. When compared with the
cost-effectiveness of various effluent .
guidelines, these values are at the low
end of the range of $1-$500.
5. Sensitivity Analysis
Two additional analyses were
conducted to assess the impact on the
cost-effectiveness of assuming that
baseline values reported as less than a
detectable value equal one-half the
reported detection level. The following
alternatives for addressing baseline
values reported as less than a detection
level (in the absence of a permit limit)
were evaluated:
a. The reported detection level was
used as the baseline concentration.
b. Zero was used as the baseline
concentration.
Using the first alternative resulted in
about a 22 percent increase in total
annual pounds-equivalent removed for
Scenario 1 and about a 20 percent
increase in total annual pounds-
equivalent removed for Scenarios 2-4
when compared to the original analysis.
Cost-effectiveness values ranged from
$1.07 per pound-equivalent to $8,72 per
pound-equivalent,
Using the second alternative resulted
hi about a 22 percent decrease 'in total
annual pounds-equivalent removed for
Scenario 1 and about a 20 percent
-------
Federal Regist&r / Vol. 58/No. .72 / Friday, April 16, 1993 / Proposed Rules
20995
reduction in total annual pounds-
equivalent removed for Scenarios 2-4
when compared to the original analysis.
This assumption yielded cost-
effectiveness values ranging from $1.68
per pound-equivalent to $12.87 per
pound-equivalent for Scenarios 1-4.
/. Overview of Projected Benefits
Attributable to the Great Lakes Water
Quality Guidance
1. Introduction
The benefits analysis is intended to
provide insight into both the types and
potential magnitude of the economic
benefits expected to arise as a result of,
- the GLWQG. A qualitative assessmenfbf
these benefits is provided in section 1.2
below. In addition to the qualitative
assessment, more quantitative empirical
estimates of the potential magnitude of
•- the benefits from controlling point
sources are developed to the extent
feasible and then compared to1 the
estimated costs of controlling-point
sources in the proposed Guidance. This
discussion is intended to demonstrate
data needed and a methodology suitable
for comparing benefits and costs. The
methodology used to assess benefits and
its results are summarized below. A
complete study, Regulatory Impact
Analysis of the Proposed Great Lakes
Water Quality Guidance, is available in-
the administrative record for this
rulemaking. EPA invites comments and
requests that the commenters provide
. detailed analysis and data to support .
their conclusions. The appropriate
documentation would enable EPA to
better evaluate these comments,
2. Qualitative Assessment of Benefits
Associated With the Great Lakes Water
Quality Guidance
This section provides a qualitative
.review of £he benefits that can be
expected from implementation of the"
proposed Guidance. This qualitative
assessment presents a characterization
of anticipated benefits based on; (a) The
sensitivity and unique attributes of the
receiving waters, (b) the natureof the ...
toxic pollutants addressed by the.
GLWQG and some implications of the
proposed Guidance for human health
and ecological risk reductions, and (c)
an overview of exposed and sensitive
populations.
a. Sensitivity and Unique Attributes of
Receiving Waters. Bioaecumulative
chemicals of concern have been.
identified for special treatment in the ''.
GLWQG. EPA believes addressing these
pollutants will yield particularly high
benefits given the sensitivity and
vulnerability of this aquatic ecosystem.
Several characteristics of the Great
Lakes make them particularly
susceptible to relatively nondegradable,
lipophilic chemicals, such as some of V
the contaminants addressed by the Great
Lakes Water Quality Guidance. These
characteristics include:
i. Long hydraulic retention time. (Less
than one percent of the total volume of
the Great Lakes drains through the St.
Lawrence River on an annual basis.
Retention times range from 173 years for
Lake Superior to 2.7 years for Lake Erie.)
ii Low suspended solids
concentration.
iii. Low biological productivity.
iv. The presence of self-contained,
vulnerable plant and animal ,
populations.
These attributes result in •
contaminants remaining in the Great
Lakes $ystem for long periods of time
and bioaccumulating in fish and
wildlife at concentrations that are orders
of magnitude above those in the water
column. Continued or new inputs of
-toxic pollutants only exacerbate this
problem. However, reductions in
loadings of pollutants will, over the long
term, reduce the rate of bioaccumulation
(see sections LA. and I.D. of this
preamble for further discussion).
Because physical and biological
processes in the Great Lakes encourage
the recycling of toxics, pollutant
loadings entering the Great Lakes
System may be more likely to impact
Great Lakes' wildlife, human and
aquatic communities than in other
ecosystems. Pollutants like the BCCs
identified in the proposed Guidance
tend to preferentially sorb to particles in
the water column, and are subsequently
transported to the bottom sediments in
many locations. Because the Great Lakes
efficiently cycle carbon and nutrients,
higher trophic levels are exposed to
many of the chemicals associated with
biotic particles and create the risk of
these chemicals bioaccumulating up the
food chain/Pollutants are also released
back to the water column as particulate
matter is degraded by bacterial action,
posing further risks to the fish and \
wildlife. Even those particles that do
reach the bottom sediments are subject
to resuspension during storm events.
While concentrations of these
contaminants in current loadings may
be expected to decline, the rate of
decline in the total mass of these
contaminants for the Great Lakes
System, will occur much more slowly
. than in systems with shorter hyftraulic
retention times, or greater sedimentation
rates (EPA Region V, Great Lakes
National Program Office, Great Lakes
Risk Characterization Study, Review
Draft, Chicago, IL, 1991). Accordingly,
any new discharges of bibaccumiilative
pollutants of concern will add to food :
web contamination and prolong the
time for the full restoration of beneficial
uses of the Great Lakes and^ -^
unacceptable levels of risk to human,
wildlife and aquatic populations which
utilize the Great Lakes Basin Ecosystem.
1 For a number of years, the monitored
concentrations of bioaccumulative .
chemical contaminants have declined in
Great Lakes fish. Based on a review of
lake trout and coho salmon data
collected through 1990, however, it
appears that the rate of decline in
contaminant concentrations in fish
tissue is slowing, and approaching zero
(EPA Region V, 1991). Additionally,
these data show; that fish tissue
concentrations are stabilizing at
unacceptabiy high concentrations,:- '
despite the decreased loadings resulting
from previous regulatory actions.
Contaminant concentrations measured
in 1990 for PGBs and chlorinated
pesticides exceed fish tissue ,
concentrations allowable .under current
EPA water quality criteria, by several
orders of magnitude. If, as the data
suggest, a new equilibrium in ambient
water quality and fish tissue
concentrations is being reached given'
current loading rates for these
pollutants, then substantial further .-'••-
reductions in loadings may be necessary
to achieve fish tissue concentrations
that would provide for the lifting of fish
advisories and bans imposed at present
in the Great Lakes region (EPA Region
V, 1993).
Finally, in recognizing the sensitive
nature of the Great Lakes System,
recommendations calling for special,.
more restrictive measures for toxic
pollutants will be consistent with the
Greatlakes Water Quality Agreement
goal of virtual elimination of persistent
toxics, the Great Lakes Governors'
Toxics Substance Control Agreement ,
calling for continued reduction of toxics
in the Great Lakes System to the
maximum extent possible consistent
with the Clean Water Act and Great
Lakes Water Quality Agreement, and the
fishable goal of the CWA. In addition to
the purely ecologicbenefits associated-
with reductions'in loadings of . '
bioaccumulating toxics, these
reductions will generate significant
benefits associated with improved
opportunities for human uses of the
fishery and related resources: increased .
recreational fishing and hunting
opportunities, the potential fpr-c- - - ,-,.
commercial fishery expansion; and
increased opportunities ahdV values to
other recreational users of Great Lakes
basin waters.
b; Nature of Toxic Pollutants
Addressed by the GLWQG and: ;1: "
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20996
Federal Register / Vol. 58, No. 72 / Friday, April 16,-'199-3 /* Proposed Rules
Implications for Risk Reduction. The
benefits of controlling discharges under
tha proposed Guidance depend on the
characteristics of the specific pollutants
that are reduced. A number of these
pollutants (those associated with control
of point source discharges), and
associated health and ecological risks,.
are summarized in Table IX-5. This
table illustrates several key points:
i. All compounds are highly
persistent, implying that future
reductions hi loadings will yield long-
term benefits. However, for the same
reason, current ambient conditions, due
to past loadings, are likely to delay the
realization of benefits for manv vears
into the future
-i - • i, * • •„ -
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Federal Register /.Vol. 58, No. 72 /Friday, April 16, 1993 /Proposed kules
120997
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20998 Federal Register / VoL 58. No. 72 A Friday, April 16, 1993-/ Proposed Rules
ii. Half the compounds have a
relatively high potential for
Moacctanttlation. The implications are
consistent with those raised above with
respect to the persistence of the toxics—
®,g., even if all future loadings are
eliminated and reductions in water
column and sediment concentrations
are realized, it will take many years for
tissue concentrations of these pollutants
to decline in impacted biota to the point
where residual risks have been
minimized.
iii. Dioxin and PCBs are considered
probable human carcinogens via
ingest ion, and both also are associated
with systemic (i.e., noncarcinogenic)
health risks. Cadmium, cyanide and
mercury also are of high concern for
systemic human health risks (kidney
and central nervous system). While
human health risk reductions may not
ba tho primary motivation for the
CLWQG, the potential for reducing
these risks may be appreciable.
Furthermore, because noncarcinogenic
effects of the contaminants are
presumed to exhibit threshold dose-
response functions, it is more difficult
to quantify reductions in these types of
risks than it is to quantify carcinogenic
risks.
Iv. Most of the toxics addressed in the
GLWQG pose relatively high risk to
aquatic and terrestrial organisms, both
to tho survival of living organisms and
thek reproductive capacity. These risks
imply that the primary benefits of the
GLWQG will be related to ecologic
concerns. The toxics controlled by the
GLWQG pose risks to species of concern
and value apart from direct
consumptive use for recreation,
commercial or other such purposes. For
example, bald eagles, osprey,
cormorants, mink, otter and other
important piscivorous species are likely
to face reduced mortality risk and
increased breeding success if the levels
of the compounds are reduced in the
Groat Lakes environment. The resulting
benefits to society extend beyond more
commonly measured consumptive use
values and include nonuse or intrinsic
benefits, (nonconsumptive and indirect
use benefits also are relevant) and
option values (which are also
considered, in most circles, as a form of
us® value).
Tho persistence and toxicity of the -
compounds to be directly controlled
from point sources under the GLWQG
have important implications for the
benefits analysis. The principal benefits
exhibit characteristics that make them
less amenable to empirical evaluation
than benefits for other EPA actions
because: (l) Temporally, most of tha
direct benefits are likely to be delayed
for many years, and (2) structurally, the
benefits are largely of the ecologic or
nonuse variety.
c. Overview of Exposed and Sensitive
Populations. The potential for
significant health risk reduction benefits
exists for certain populations who may
be unaware of or ignore fish
consumption advisories. For example,
Native American .tribes in the Great
Lakes basin also tend to consume a
greater amount of local fish than the
general population, and thus are at
greater risk than the average exposed
population for any associated health
effects. East Asian populations such as
the Hmong who rely heavily on
subsistence fishing, and for many of
whom English is a second language,
may be particularly vulnerable to
exposing themselves to toxic •
contaminants in fish. Finally, while
advisories warn against consumption,
many anglers consume recreationally-
caught fish in excess of the
recommended quantity. All of these
populations will benefit from reduced
health risks as the concentrations of
toxic compounds in fish decrease.
d. Conclusions. The benefits
associated with the proposed Great
Lakes Water Quality Guidance may be
substantial due to the significant health
and ecologic risks posed by the
chemicals addressed by the proposed
Guidance, when combined with
physical characteristics of the Great .
Lakes that cause them to be particularly
vulnerable to bioaccumulative toxic
pollutants. Given the long retention
time, low sedimentation, low .
productivity in the Great Lakes System
and presence of-self contained,
vulnerable populations (and hence the
persistence of toxic contaminants in this,
ecosystem), loadings reductions realized
as a result of the GLWQG are expected
to have lasting impacts on mortality risk
and the reproductive success of many
aquatic, avion, and mammalian species
of concern. These benefits include
increased productivity and protection of
biological diversity,of Great Lakes
species including salmonids and other
fish species, cormorants, eagles, osprey,
and otters. -.-..-•
" Fish arid waterfowl consumption
• advisories are likely to be lifted as •
concentrations of toxic compounds are
reduced. Such actions, and water ••
quality improvements leading to those
actions, would result in increased
recreational fishing and hunting
opportunities and increased values for.
recreational fishing and hunting days.
According to the U.S. Fish and Wildlife
Service's 1985 National Survey of
Fishing, Hunting, and Wildlife- :
Associated Recreatioa (U.S. Department
of the Interior, Washington, B.C., 19891
the Great Lakes supported more than 46
million angler days in that year. Even a
small increase in the-number of angler
days or the value associated with
improvements in Great Lakes angling
would provide significant annual
benefits. Other recreational
opportunities, including boating,
swimming, and wildlife observation-
would also be expected to be enhanced
as water quality and ecosystem health
improve. Health risk reduction benefits
are likely to be generated through
reduced exposure via the following
pathways: fish consumption
(particularly among subsistence
populations relying on Great Lakes fish
and wildlife as a primary food source),
ingestion of contaminated drinking
water, and incidental forms of exposure
to contaminants through recreational
activities such as swimming. The value
of these improvements touch not only
direct users of the Great Lakes, but also
nonusers who ascribe values to the
ecologic benefits resulting from the
implementation of the proposed
Guidance. ,
3: Economic Concepts Applicable to: •
Quantitative Benefits Analysis
a. The,Economic Concept of Benefits.
The term economic benefits refers to the
dollar value associated with all of the
expected, direct positive impacts of the
Initiative; that is, all GLWQG outcomes .
that lead to higher social welfare.
Conceptually, the monetary value of
benefits is embodied by the sum of the
predicted changes in consumer (and -
producer) surplus. These surplus-
measures are standard and widely •
accepted terms of applied welfare
economics, and reflect the degree of
well-being enjoyed by people given
different levels of goods and prices '
(including those associated with . -.,
en vironmental quality). '
This conceptual economic foundation
raises three relevant issues and potential
limitations for the benefits, analysis of
the GLWQG. First, the standard
economic approach to: estimating
environmental benefits is • -
anthropocentric—all benefit values arise
from how environmental changes are
perceived and valued by humans. ;
Second; benefits of all future outcomes
are valued by the present-day human
population. Third, all near-term as well
as temporally distant future physical ,
outcomes associated with reduced
pollutant loadings need to be predicted --
, and then translated into the framework . -
of present-day human activities and
concerns.
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Federal Renter / Vol. 58, No. 72 ;/ '
'April '16, "LQ&X / Prdposed "Rules
20999
b. Benefit Categories Applicable to the
GLWQG. EPA divides the potential
benefits associated with the GLWQG
into two broad categories: use benefits
and nonuse benefits (also referred to as
passive use, or intrinsic benefits}. The
use benefit category can embody both
direct and indirect uses of the impacted
waters, and the direct use category •
embraces both Consumptive (e.g.,
fishing} and non-consumptive (e.g.,
wildlife observation) activities. In most
applications to pollutant reduction
scenarios, the most prominent usa
benefit categories are those related to
^recreational fishing, boating and/or
'swimming.
Whether or not recreational use
benefits reflect society's prime
motivation for environmental protection
measures is unclear; however^
recreational activities are amenable to
various non-market valuation -
techniques (e.g., travel cost models) and,
accordingly, have received considerable
empirical attention from economic
researchers' over the past two decades.
Thus, there is a considerable body of
knowledge relating to recreational
fishing and related activities,, and these
generally indicate that water-based
recreation is a highly valued activity in
society. Accordingly, many benefits-
analyses focus on recreational values •
because they are well understood, there
is a large body of empirical research to
draw upon, and the associated benefits
tend to be quite large>
Improved environmental quality can
be valued by individuals apart from any
past, present or anticipated future use of
the resource in question; Such rtomise
(or passive use) values may be of a
highly significant magnitude; but the
benefit value to assign: to these .
motivations often is a matter of .
considerable debate. Whereas, human
uses of a resource- can be observed
. directly and valued with a range of
technical economic techniques, non-use
values can only be ascertained from-'
directly asking survey respondents to
reveal their values. The inability to rely
on revealed behavior to ascertain non-
use values has led to-debates as to
whether they exist for applicable '
changes in environmental quality and, if
so, whether they are of an, appreciable
magnitude relative to use values. As
described below, there is reason to
anticipate that non-use benefits are
relevant and may be appreciable for the
proposed Guidance.
Among the rnors relevant non-use
values associated" with the GLWQG, are-
ecological benefits associated with,
decreasing the level of toxic compounds-
found in Great Lakes waters and
sediment. Such ecological benefits' are .
likely to embody reduced risks, of direct
mortality, arid increased reproductive
success, in a range of important fish and
wildlife species. The species include,
but are not limited to; bald eagles,
cormorants, and other piscivorous avian
species; mink, river otter and other
mammalian species that feed on fish
and crustaceans; an
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21000 federal Register / Vol. 58, No.. 72 "I Friday, April 16. 1993"/'Proposed Rules
progress, or anticipated, absent the
GLWQG. Therefore, there is an
important distinction between present
observed conditions, and the conditions
that reflect the relevant baseline for the
GLWQG.
Benefit analyses can be designed to
measure actual or theoretic changes in
water quality conditions. In both cases,
there must be a well defined baseline
condition beyond which«the value of
water quality improvements can be
measured. In this instance, the
establishment of a baseline level of
water quality conditions upon which
the benefits of the GLWQG should be
measured must be ascertained to
estimate the benefits relevant strictly to
the GLWQG. Benefits of improvements
expected to occur as a result of current
requirements need to be distinguished
from the benefits for which will accrue
as the results of the implementation of
tho final Great Lakes Guidance. In some '
instances, distinguishing between the
two la relatively straight forward. At
other times, several assumptions must
be made and believed to allow the two
stages to be distinguished from one
another.
One approach for attributing benefits
to the GLWQG is to discern how toxic
loadings reductions will change from
present conditions to the WQG-relevant
baseline, and then from this baseline to
tha post-GLWQG loadings.
Unfortunately, the absence of loadings
data for all potential sources of toxics
(i.e., point and nonpoint sources) does
not allow for an assessment of the
results of the GLWQG to present
conditions. However, point source
loadings reduction estimates due to the
GLWQG relative to expected loadings
that would be observed subsequent to
compliance with current regulatory
requirements indicate a substantial
reduction in tojdcity-weighted loadings
of pollutants could be achieved. Thus,
while the GLWQG will have a
significant impact relative to loadings at
its baseline, we have no empirical
information with which to discern how
this reduction compares to differences
that may exist between present
conditions and the GLWQG-relevant
baseline. The absence of this data makes
it difficult to attribute benefits to the
GLWQG on the basis of changes in
loadings with any certainty.
d. Contingent Valuation Method
Issues, The empirical results presented
at the casa study analyses utilize
benefits estimates from relevant
research on water quality
improvements. Several of these
estimates include results derived from
contingent valuation methodology
(CVM) (as well as Jhe travel cost
methodology (TCM) and other
techniques). CVM is an approacn in
which hypothetical markets are
constructed and presented to^
individuals in a survey format, with the
responses used to infer prices and
values for the goods and services being
evaluated (such as those associated with
different levels of environmental
quality). Because the CVM approach
relies on survey responses to
hypothetical conditions and markets,
CVM is considered a potentially biased
approach to estimating benefits.
In particular, there is an inherent
degree of skepticism among some
economists regarding the accuracy of
results derived from the CVM approach
relative to those derived from economic
research methods that rely on revealed
human behavior, such as TCM.
Likewise, where there are no means of
relying on revealed behavior as a '
possible benchmark for accuracy and
validity, such as in estimating nonuse
values with CVM, the approach has
been the subject of considerable debate.
The issues surrounding the general
validity of the CVM approach are
discussed in the RIA, and have been the
subject of peer reviewed economics
literature for more than a decade (see,
for example, R.G. Cummings, D.S.
Brookshire and W.D. Schulze, Valuing
Environmental Goods, Rowan and
Allanheld, Totowa, N.J., 1986; R.G.
"Cummings and G.W. Harrison,
Identifying and Measuring Nonuse
Values for Natural and Environmental
Resources: A Critical Review of the
State of the Art, Final Report, April
1992). Scholarly insights from a broad
range of relevant disciplines, including
psychology and statistics as well as
economics, have also been brought to
bear on defining appropriate approaches
to developing, implementing, and '
interpreting state-of-the-art,
professionally credible CVM
instruments and results (e.g., R.C,
Mitchell and R.T. Carson, Using Surveys
to Value Public Goods: The Contingent
Valuation Method, Resources for the
Future, Hopkins University Press,
Washington, DC, 1989).
As in any economic research
technique, the credibility, accuracy, and
robustness of CVM-derived results
depend entirely on the research protocol
applied by the practitioners in designing
and implementing the CVM survey
instruments, Poorly designed and
executed CVM surveys are likely to '"
generate results that may be biased and
misleading. However, careful design
and implementation of surveys allow
researchers to test for (and account for)
potential biases and embedded values.
In brief, each CVM study.must be.
evaluated and interpreted on its own
merits; tnere are many nigh quantj
CVM research efforts that provide
credible and reliable information;
Accordingly, among numerous
academic and applied economic
researchers, CVM is recognized as
capable of providing robust and credible
benefits estimates.
Indeed, a NOAA Blue Ribbon Panel
review (K. Arrow, R, Solbw, i-.R.
Portney, E.E. Learner, R. Radnerv and H.
Schuman, Report of the NOAA Panel on
Contingent Valuation, U.S. Department
of Commerce, National Oceanic and
Atmospheric Administration, Rockville,
Maryland, 1993) of CVM to measure
nonuse values concluded that CVM can
produce reliable estimates for use in the
litigation process to determine natural
resource damages. The panel set forth a
number of guidelines for CVM'survevs
The guidelines address survey design
(including the recommendation of a
personal interview format); elicitation
format (including the recommendation
of a conservatively designed referendum
eliciting willingness to pay (WTP) and
checks on understanding and
acceptance); and additional issues that
CVM surveys should explicitly address
(e.g., the warm glow of giving effect).
The Panel maintained that use of these
guidelines will generate more reliable
results.
The NOAA panel evaluated CVM as a
means of estimating nonuse values for
use in litigation to determine the
liability of a specific party rather than •
for use in a public policy setting. Thus,
the applicability of the standards set by
the Panel to analysis of regulatory
impacts should be evaluated
considering that the estimates are used
in an informational context, to compare
benefits to costs. Failure of the CVM
studies utilized in the case studies
analyses to conform to all of the NOAA
recommendations should therefore not
automatically preclude them from being
considered as a source for benefits
information.
i. Using CVM to Estimate Use
(Recreational) Benefits The issues
associated with using CVM for use
values (e.g., recreational benefits) are
somewhat distinct from those of
estimating nonuse values. Since
recreational activities are amenable to
various non-market valuation
techniques, one means of assessing the
accuracy of CVM results for estimating
use values is to compare results of CVM
research for use benefits With those for
other valuation methods which rely on
revealed behavior (e.g., TCM,; hedonic
pricing). Examples can be found in the •
comparative reviews of R.G. Walsh
'D.M. Johnson, and J.R McKean
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Federal Register /Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rales
21001
(Nonmarket Values From Two Decades
of Research on Recreation Demand,
Advances in Applied Microeconomics,
Vol. 5, V. K. Smith arid A.N Link (eds),
JAI Press Inc.,1990); Cummings,
Brookshire, and Schulze (1986); and A. r
M. Freeman .(The Economics of Valuing
Marine Recreation: A Review of the >,
Empirical Evidence, Draft Report to
OPPE/USEPA, Washington, D; C.,1992).
These studies reveal that the accuracy of
both types of methodologies depends
heavily on the study design, ana both
iriethodologies can produce wide
ranging estimates as a result.
, Furthermore, (JVM studies of recreation
use benefits have performed reasonably
well when compared to the available
evidence from travel behavior, actual
cash transactions, and controlled :
laboratory experiments. : .
ii. Using CVM to Measure Nonuse
Values. CVM provides a method for
directly eliciting nonuse values where
• there do not appear to be direct market
' transactions or indirect methods based.
on market behavkfr available to reveal ,
these values. Indeed, CVM's greatest
asset is its potential to measure any
benefit category. As is the case with use
values, efforts to measure nonuse values
by CVM must be thoughtfully
conceived, well designed, and carefully
, implemented. Where testable (recreation
values only), estimates for use values
from high quality. CVM studies have
been found to compare favorably with
results obtained from other accepted
valuation methods. Providing similar
.test results for nonuse values has proved
difficult, and thus critics of the CVM
approach have questioned the reliability
of CVM in estimating nonuse values for
which alternate measures of comparison
are difficult, if not impossible, to
construct. While the NOAA Panel found
the criticisms of CVM to take on added
importance in light of this absence of
alternate measures with which to
compare the .estimates, it recognized
that this problem would be inherent in
any method of estimating nonuse
values, . '
5.:Cost-Effectiveness of theProposed
Guidance at Three Sites . :•
• For each of the. three case studies (Fox
River/Green Bay, WI; Saginaw Bay, MI;
and Black River, OH), loadings
reductions were estimated for cost
scenarios 1 and 2 using the approach
outlined earlier. These, loadings were
then converted into toxicity-weighted .
pounds (or pounds-equivalents).
Pounds-equivalent per day were
multiplied by 365 days to obtain annual
reductions in the loadings. Total
annualized costs for .Scenarios 1 and .2
.were then divided by the total annual
reductions in toxkaty-weighted pounds
to obtain $ per pound-equivalent. -.-.-•.
The cost-effectiveness values for all
four Scenarios in the Fox Raver case
study range between $0.80 per pound-
equivalent and $4.02 per. pound-
equivalent over the baseline. The cost
effectiveness for the most likely
scenario, Scenario 2, is $146 per pound
equivalent. The cost-effectiveness for
the Sagiriaw Bay case study is between"
$1.70 per pound-equivalent and $22.50
per pound-equivalent over the baseline
for all four scenarios. The cost-
effectiveness for the most likely scenario
is about $4.62 per pound-equivalent
over the baseline. The cost-effectiveness
of all four scenarios for the Black River '.
case study range between $8.08 per
pound-equivalent and $164.73 per "'
pound-equivalent over the baseline. The
cost-effectiveness of the most likely '
scenario is $22 41 per pound-
equivalent. The results of these analyses
are presented in more details in the
Regulatory Impact Analysis of the :
Proposed Great Lakes Water Quality ;
Guidance,
6 > Future Analysis :
The discussion above provides useful
insights into the potential impacts of the
proposed Guidance. It also indicates
areas in which additional analysis and
research may be useful for strengthening
our understanding of the GLWQG, the
Great Lakes Basin Ecosystem, and,
poh'cy analysis in general. Areas which
the EPA will consider for future
analyses include:
a. Obtain more information and
conduct more sophisticated analyses to.
estimate the appropriate baseline for
analyzing the GLWQG, and the
improvements beyond that baseline
attributable to the GLWQG. These
efforts might focus on pollutant
loadings, the -physical/chemical
properties 6f receiving waters, and
aquatic ecosystem impacts. This would
help define more reliable means for
assigning benefits to the GLWQG than
has been attempted in these case "
studies.
b. Expand the effort to encompass a
broader array of case study sites. The
benefits and costs of water quality
improvements are highly site-specific.
The analysis can be broadened to
portray this, and establish a framework
by which information from case studies
can be used to represent aggregate
benefits of the GLWQG. ,
c. Incorporate Monte Carlo or Other
Sensitivity Analysis Techniques into the
analysis to more clearly and insightfully
portray the uncertainties in the results,
and the extent to which the assumptions
necessary to conduct the analysis ."•...
influence the outcomes. ' v
d. Broaden the perspective of the case
studies to examine and properly
account for the full suite -e£
environmental actions necessary to , ;
realizing important threshold-like
improvements in water quality. Benefits
typically accrue only when discrete
changes in the environment are realized,
and such changes generally arise as a...
joint product of several efforts v
implemented over a course of time (e.g.,
nonpoint source controls as well'as
point sourca controls may both be
required to attain fishable waters). The
case study approach is a valuable tool
for clearly identifying and assessing
these multiple program arid associated
benefits apportionment issues.
e. Define, assess and interpret options
for explicitly addressing the issue of
how to portray arid account for long-
term ecologic benefits in a benefit-cost
.analysis such that it appropriately
balances normative concerns within a
positive analytic paradigm.
The results of additional analyses will
be placed in the record. ,
• This proposed rule was submitted to"
the Office of Management arid Budget
for review as required by Executive
Order 12291.
X. Regulatory Flexibility Act
Under the Regulatory Flexibility Act
(RFA), 5 U.S.G. 601 et seq., EPA must
prepare a;Regulatory Flexibility'
Analysis for regulations having a
significant impact on a substantial
number of small entities. The RFA
recognizes three kinds of small entities
and defines them as follows:
—Small governmental jurisdictions—
any government of a district with a .,.
population of less than 50,000.
—Small business—any business which
is independently owned and operated
and not dominant-in its field as
••; defined by Small Business
. Administration regulations under
Section 3 of the Small Business Aci,
-^Small organization—any not-for-profit
enterprise that is independently
owned and operated and not
\ dominant in its field. >; •
As discussed in section IX above,
small facilities are projected to incur
less than $3,300 per facility to comply
with the requirements in the proposed
Guidance. These costs are not expected
to impose economic burdens on small
facilities. Accordingly, I certify pursuant
to 5 U.S.C. 605(b) that the proposed -"„
Guidance, if implemented, will not have
a significant impact ;qn a substantial
number of small entities and.that a
Regulator* Flexibility Analysis, .-,.-.,.
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21002
federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
therefore, is unnecessary. After the
proposal, EPA is planning to conduct a
moro detailed economic analysis and
Will reconsider this determination, if
warranted.
XI Paperwork Reduction Act
Tho Information collection
requirements la this proposed rule have
boon submitted for approval to OMB
imdor th0 Paperwork Reduction Act, 44
U.S.C. 3501 et seg. EPA has prepared an
Information Collection Bequest (ICR)
document (ICRNo. 1639.01). Copies of
tho 1CR may be obtained by writing
Sandy Farmer, Information Policy-
Branch, EPA, 401M St., SW. (PM-
223 Y), Washington, DC 20460, or by
calling (202) 260-2740.
Tho public reporting burden for this
collection cf information is estimated to
ba 80,283 hoos for the 3,795
pannlttees, or aa average 18,2 hours.
Sand comments regarding the burden
estimate or ar.y other aspect of this
collection cf information, including
suggestions for reducing this burden to
Chief, Information Policy Branch. PM-
223Y, U.S. Environmental Protection
Agency, 401M St. SW., Washington,
DC 20460; and to the Office of
InfornjiaJion and Regulatory Affairs,
QfficfljfCManagementand Budget,
WasBiigton, DC 20503 The final rule
Will respond to any OMB or public
comments on the .information collection
requirements contained in this proposal.
Xtt Judicial Review of Provisions not
Amended
In some situations, EPA is proposing
renumbering or other editorial changes
to regulations that have already been
promulgated, or to provide for ease in
reading proposed changes is repeating
an entire section, including the portions
not changed. The proposal and
promulgation of these regulations does
not provide another opportunity to seek
judicial review on the substance of these
regulations.
XHI. Supporting Documents
All documents that are referenced in
this preamble are available for
inspection and photocopying in the
administrative record for this
rulemaldng at the address listed at the
beginning of this preamble. A
reasonabfe fca will be charged for
photocopies.
Tha documents listed below are also
BVftllablo for a fee upon written request
or telephone call to the National
Technical Information Center (NTIS),
US, Department of Commerce 5285
Port Royal Road, Springfield, VA 22161
Tho toll fre« number is 800-33,6-4700
and the local number is 703-487—4650
Alternatively, copies may be obtained
for a fee upon written request or
telephone call to tho Educational
Resources Information Center/
Clearinghouse for Science, Mathematics,
and Environmental Education (ERIC/
CSMEE), 1200 Chambers Road, room
310, Columbus, Ohio 43212 (phone
number: 614-292-6717). When
ordering, please include the NTIS or
ERIC/CSMEE accession npnber.
A. Great Lakes Water Quality
Initiative Criteria Documents for the
Protection cf Aquatic Life in Ambient
Water. NTIS Number: PB93-154656.
ERIC Number: 3900.
B. Great Lakes Water Quality
Initiative Technical Support Document
for the Procedure to Determine
Bioaccumulation Factors, NTIS Number:
PB93-154664. ERIC Number: 3910.
C. Derivation of Proposed Human
Health and Wildlife Bioaccumulation
Factors for the Great Lakes Initiative.
NTIS Number: PB93-154672. ERIC
Number: 3920.
D. Great Lakes Water Quality
Initiative Criteria Documents for the
Protection of Human Health. NTIS
Number: PB93-154880. ERIC Number:
3930.
E. Great Lakes Water Quality Initiative
Technical Support Document for
Human Health Criteria and Values, -
NTIS Number: PB93-154698. ERIC
Number: 3940.
F. Technical Support Document: •
Establishment of Ambient Screening
Values Under the Great Lakes Water
Quality Initiative. NTIS Number: PB93-
154706. ERIC Number 3950.
G. "Analysis of Acute and Chronic
Data for Aquaticlife," Host, G.E., R.R,
Regal, and C.E. Stephen, ,1-4-91 draft.
NTIS Number: PB93-154714. ERIC
Number 3960.
H. Great Lakes Water Quality
Initiative Criteria Documents for the
Protection of Wildlife. NTIS Number;
PB93-154722. ERIC Number. 3970.
I. Assessment of Compliance Costs
Resulting from Implementation of the
Proposed Great Lakes Water Quality
Guidance. NTIS Number. PB93-154730.
ERIC Number 3980
J. Regulatory Impact Analysis of the
Proposed Great Lakes Water Quality
Guidance. NTIS Number PB93-154748.
ERIC Number 3990,
Appendix to the Preamble—Great
Lakes Water Quality Initiative
Technical Support Document for
Wildlife Criteria .
Note: This appendix to part 132 contains
.background material and material intended
to clarify portions of the regulation. It does
not establish any additional regulatory
requirements. ..-.•'•
I. Introduction
; The waters of the Great Lakes System
provide vital resources not only to
support numerous critical human
activities and habitat for aquatic
organisms, but also to sustain viable
mammalian and avian wildlife
communities. In order to assure that the
quality of the waters in the System are
adequate to support these uses, specific
water quality criteria need to be set.
The purpose cf establishing water
quality criteria for wildlife is to
determine surface water concentrations
of toxicants that will remain protective
of avian and mammalian wildlife
populations that utilize waters,of the
Great Lakes System as a drinking and/
or foraging source. Specifically, each
criterion is the highest calculated ,
aqueous concentration of a toxicant
which causes no significant reduction in
the viability or usefulness (in a
commercial or recreational sense) of a-
population of exposed animals over
several generations. For the purpose of
these regulations, this concentration is
called the Great Lakes Wildlife Criterion
(GLWC).
Ideally, a safe concentration of a given
pollutant would be calculated for every
species and the GLWC would be
determined based on the distribution of
these values across all species (an
approach similar to that used in
deriving criteria to protect aquatic life,
Stephen et aL, 1985,).Therefore, an
approach similar to that proposed to
derive a noncancer human health
criterion (section ffl.C.3 of appendix C
to part 132 of this rule. Methodologies
for Development of Human Health
Criteria and Values) was used in which
representative wildlife species were
selected to establish the basis for
employing interspecies unqertainty
factors for extrapolation of toxicity data
and to define specific exposure
parameters. Five Great Lakes basin
wildlife .species representative of avian
and mammalian species resident in the
Great Lakes basin which are likely to
experience significant exposure to
contaminants through the aquatic food
web were identified. These species are
the bald eagle, osprey, belted kingfisher
mink, and river otter. A Wildlife Value
(WV) is calculated for each
representative species (which is a safe
concentration of a given pollutant) and
then the geometric mean of these values
within each taxonomic class is
determinetLThe GLW'C is the lower of
two class-specific means. . • , .
To derive the WVs from whkh the
GLWC is determined, scientific
literature for the toxicant of concern is
reviewed for mammalian and. avian. .
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Federal Register / Vol. 58, No. 72 /Friday, April 16, 1993 / Proposed Rules
21603
toxicity studies that meet the minimum
toxicity database requirements. A tiered
approach, is used in the derivation of -
these criteria. Tier I values are
developed for chemicals with databases
providing a high level of certainty in
quantifying concentrations at which
adverse effects may be experienced by
the avian and mammalian wildlife
communities. EPA is proposing four
specific Tier I criteria that will be
applicable across the Great Lakes
System. States and Tribes will be
expected to adopt into regulation these
criteria (or more stringent values). They
will also be expected to adopt the
procedure for developing Tier I values
for additional substances. EPA
encourages States and Tribes to adopt
these Tier I values as criteria.
Chemicals with less extensive data, or
where the level of certainty is less, are
subject to Tier E values. States and
Tribes will be expected to adopt, by
regulation, the procedure for developing
Tier II values, rather than the numeric
values the procedure generates.
H. Calculation of Wildlife Values for
Tier I Criteria and Tier II Value
Development . / :'
A Derivation of Equation
The equation used to calculate
Wildlife Values (WV), and ultimately .
the GLWC, has both a hazard and
exposure component. The hazard :
component contains the NOAEL—the .
highest tested dose of a substance which
does not result in an observed adverse
effect. The exposure routes considered
in this derivation are food and water
ingestion. The intake level is dependent
.on organism size and therefore it is ,
scaled to body weight. The total toxicant
intake through these exposure routes is
detennined and then set equal to the
NOAEL as follows:
Toxicant intake through drinking
water=(WVxWA)/WtA (Equation 1)
Toxicant intake through ,
food=(WVxFAxBAF)/WtA (Equation
2) ; , ,-"_: -.. • -•;• ..
Where: ' '.
Wy=Wildlife value in milligrams of
- substance per liter (mg/L).
WA=Average daily volume of water ..
consumed in liters per day (L/d) by
the representative species identified
for protection or the species
identified as. requiring greater :
protection.
FA=Average daily amount of food
consumed in kilograms per day (kg/
d) by the representative species
identified for protection -or the
species identified as requiring
greater protection.
BAF=Aquatic life bioaccumulation
factor for wildlife in liters per
kilogram (L/kg). Chosen using
guidelines for wiloUife presented in
appendix B to part 132 of this rule,
the Methodology for Development
of Bioaccumulation Factors.
WtA=Average weight in kilograms (kg)
for the representative species
identified for protection or the
species identified as requiring
greater protection. -
Equations one and two are combined
to yield Equation three.
NOAEL > (WV x WA) / WtA + (WV x FA x BAF) / WtA
(Equation 3)
Where:
. NOAEL=No observed adverse effect
level in milligrams of substance per
kilogram of body weight per day
(mg/kg - d) as derived from
mammalian or avian toxicity
, .studies.
Factoring and rearranging produces:
wy< NOAELXW.,
, ; WA+[FAXBAF]
(Equation 4)
To account .for differences in toxicity
among species, the NOAEL is .
multiplied by the species sensitivity
factor; SSF. The final equation for the
WVis: -"" -
[NOAEL x SSF] xWtA
-... " (Equation 5)
B. Weight of the Test Animal,
Representative Species, or Species
Requiring Greater Protection ,
The weight of the test animal may be
. needed to convert the NOAEL
determined in the study to the correct
units for use in the equation to derive
a Wildlife value. If a species is identified
as requiring greater protection said is.not
one of the representative species, its
weight is needed for calculation of the
, GLWC. If this information is not given
in the chosen study, the average weight .
of the test species shall be detennined
from available literature, including, if
, necessary, metabolic rate models, such
as those .presented by Nagy (1987), and
discussed further, below.
C. Drinking and Feeding Rates for the
Test Animal or Species Requiring
Greater Protection '"; .
A feeding and drinking rate for a
species identified as requiring greater
protection and which is not one of the
representative species identified for " -
protection may also be needed for
calculation of the GLWC. These rates are
needed to accurately predict exposure.
When consumption rates are given in
the study of choice, they may be
substituted directly into the equation. If
. this information is not available from,
the chosen toxicity study, it shall be •"
obtained from other appropriate '
Hterature concerning the species. In
some instances, however, this :
information is not available directly and
needs to be estimated. The following
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'Federal Register /-Vol. 58, No. 72V Friday, AprillB, 1993 / Proposed Rules
reference may be consulted for studies
dona with domestic laboratory animals:
Registry of Toxic Effects of Chemical
Substances (National Institute for
Occupational Safety and Health, the
latest edition).
When insufficient data exist for other
mammalian or avian species, the
allometric equations presented in
appendix D to part 132 should be used
to approximate the needed feeding or
drinking rates. These equations were
adopted from Calder and Braun (1983),
and Nagy (1987),
When replicated data exist, best
professional judgement will be used ir
iho selection of a single value. Barring
th«t« the geometric mean of the data
points will be utilized as the
representative value.
HI. Parameters of the Hazard
Component of the Wildlife Criteria
Methodology
A. Minimum ToxicityDatabase fot Tier
I Criteria Development
The 90-day requirement for
mammalian studies and the 28-day
requirement for avian studies are to
erasure that the toxicity data on which
a wildlife criterion is based exceeds an
acute exposure, which may
underestimate the potency a compound
would have following a chronic
exposure. These minimum test length
requirements are to be applied to both
fiold and laboratory studies.
B. Minimum Toxicity Database for Tier
II Wildlife Value Development
For those substances for which Tier I
criteria cannot be derived, all data from
avian and mammalian species may be
considered in the development of Tier
E values. Subchronic or chronic toxicity
data shall be used whenever available.to
derive a no observable adverse effect
loval (NOAEL) for Tier H values. There
are two major differences hi data
requirements for Tier n values: (1) The
minimum database requirements
presented for the derivation of a Tier I
wildlife criteria must only be met for
one of the two taxonomic classes in
ord«r to derive a Tier n wildlife value;
and (2) a Tier H value may also be based
on a mammalian study which fulfills
tha requirements set forth for Tier I
criteria excepting it may have only a 28-
day duration.
LD50 and eight-day LC50 data may be
used in support of subchronic and
chronic toxidty data; however, neither
a Tier I criteria nor a Tier n value shall
be calculated solely on the basis of LD50
or eight-day LC50 data.
C. LOAEL to NOAEL Extrapolations
If a NOAEL hi proper units is
available from the scientific literature, it
may be substituted directly into the
equation. In many instances, however, a
NOAEL is unavailable and a LOAEL is •
available for a particular animal. In
these instances the LOAEL must be
adjusted to estimate a NOAEL and
converted to proper units before being
substituted into the equation.
The LOAEL is adjusted by dividing by
an uncertainty factor which typically
ranges hi value from 1.0 to 10 to lower
the LOAEL into the range of the
NOAEL. Experimental support of this
concept is provided by Weiland
McCollister (1963). A discussion and
endorsement of this concept can be
found hi Stokinger (1972) and Dourson
and Stara (1983). In addition, this
concept is endorsed by EPA in the
Federal Register for Water Quality
Criteria Documents (45 FR 79353-
79354, November 28,1980) and hi the
National Drinking Water Regulations (50
FR 46944-46946, November 13,1985).
Additional discussion on the use of a •
LOAEL to NOAEL uncertainty factor
and the determination of its magnitude
is also provided in appendix A to the
Great Lakes Water Quality Initiative
(GLWQQ Technical Support Document
for Human Health Criteria and Values,
which is available hi the administrative
record for this rulemaking.
D. Subchronic to Chronic Extrapolations
In certain instances where only
subchronic data are available,.a
subchronic to chronic, uncertainty factor
may be used to account for the
uncertainty hi extrapolating from a
subchronic NOAEL to a chronic
NOAEL. The value of the uncertainty
factor is within the range of 1.0 to 10,
depending on the dose-response of the
adverse effect. The subchronic NOAEL
is divided by the uncertainty factor.
This factor may be used when assessing
highly bioaccumulative chemicals,
. where toxicokinetic considerations
suggest that a bioassay of limited length
may underestimate hazard. This concept
and the use of a 10-fold uncertainty
factor is endorsed by EPA hi the Federal
Register for Water Quality Criteria
Documents (45 FR 79353-79354,
November 28,1980) and in the National
Drinking Water Regulations (50 FR
46944-46946, November 13,1985).
Additional discussion on the use of a-
subchronic to chronic uncertainty factor
is also provided hi appendix A to the
Great Lakes Water Quality Initiative
Technical Support Document for
Human Health Criteria and Values,
which is available hi the administrative
record for this rulemaking..
E. Species Sensitivity Factor
The NOAEL shall be adjusted to
accommodate differences hi interspecies
toxicity with the use of an uncertainty
factor. This adjustment may be
necessary since the toxicity information
upon which a criterion is developed
will not necessarily be based on a study
using the representative wildlife species
Or the species identified as requiring
greater protection. In order to provide
protection for the representative species
or the species requiring greater
protection, an uncertainty factor called
the species sensitivity factor (SSF) shall
be used, the value of which shall be
based on the physicochemical,
toxicokinetic and toxicodynamic
properties of the substance hi question.
The value of the SSF shall also be based
on the amount and quality of available
toxicological data—both the duration
and quality of available studies and the
diversity of species for which data is
available. Toxicity information for
chemicals which operate by the same
mode of action can also be considered
hi deriving the SSF for a given
chemical. The SSF is notintended to
adjust for potential differences with
regard to body weight and food and
water consumption rates between the
test species and the representative
species or species requiring greater
protection. The factor selected shall .
reflect the uncertainty with which the
available toxicity data are appropriate
for the representative species or the
species requiring greater protection.
For Tier I wildlife criteria, the SSF
generally shall be used for extrapolating
toxicity data across species within a
taxonomic class and have a value within
the range of 0.01 and 1.0. Use of a SSF
outside of this range is prohibited
unless approved by EPA. An interclass
extrapolation employing a SSF may be
used for a specific chemical if it can be
supported by a validated biologically-
based dose-response model,
incorporating acceptable endpoints, for
a chemical analog that acts Under the
same mode of toxic action.
For Tier H wildlife values, interclass
extrapolations are permitted. Because of
the uncertainties hi performing •
interclass extrapolations, the SSF for
calculating Tier n values may not be
greater than 1.0 but may be lower than
0.01 without requiring a written
justification. It is stressed that Tier E
•values are by definition and design
conservative. Tier Rvalues can be
derived when subchronic or chronic
data are available, from only one
taxonomic class; however, because there "
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Federal Register./Vol. 88*:No, 72-I Friday, April 16, 199"3 /Tiropdseif Rules
21005
- is more uncertainty in perlprming :
interciass extrapolation, a more
conservative SSF may be applied, -
. To determine the proper range for the-
.' species sensitivity factor, LD50 data
were reviewed for approximately 50
chemicals and chronic toxicity data
were reviewed where available. Table I
of the annex contains LD50 data for rune
pesticides,'PCBs (Aroclor 1242) and
2,3,7',8-tetrachlorodibenzo-p-dio:dn.
This table demonstrates how toxieity,
from certain chemicals differs among
species/Table n of this annex contains
, chronic toxicity data for organomercury
compoundsin mammalian species.
These data support both the use of an
interspecies uncertainty factor and the ';
range of the SSF established within this
procedure. :
In application, a database containing
both chronic and reproductive/. •
developmental data for a diversity of
• species may require a SSF of between
0,1 and 1.0. If these data are from
numerous species and represent 'the •
most sensitive mammalian and avian
species, the SSF maybe equal to 1.0.-.
IV. Parameters of the Exposure
Component of the Wildlife Criteria
Methodology.
' - ' _'. * • " [t'".",'.'
A. Bioaccumulation Faptors •
. A bioaccinnulation factor (BAF) is •.;„' .
necessary to estimate the. concentration
of the chemical in the; wildlife food :
source based on its concentration in the.
- water source. The procedure to derive
the BAF is specified hi appendix B to
part 132 of this rule. This methodology
. specifies that, in general, trophic level
. three and four BAFs are used in the
.derivation of wildh'fe values, although '..
options to use plant or other .trophic
level BAFs are permitted based on the
identification of species requiring
greater protection which are not obligate
piscivorous or are not .likely to consume
: only ;fish species at trophic level three
or four . . ..•:--..-
V. Determination of Species Identified
for Protection and Associated Exposure
Parameters
Wildlife exposure to environmental
contaminants in aquatic systems can be
quite variable depending on natural.
. history characteristics of species and on
animal physiology. Furthermore, for ,
most species there are few data to,
estimateiexposure in nature (e.g.,,
ingestion rates of natural foods, field
. metabolic rates). The procedure
outlined below integrates appropriate ..
exposure information for a broad array
:' of species with variable exposure , '
; scenarios-and was used to determine
representative! species idenUfiedfor
protection in deriving the Great Lakes
Wildlife Criteria. .This analysis also
supports the WV derivation procedure
. which reflects an approach similar to -
the human non-carcinogen: water quality
criteria derivation procedure.
A. Selection of Species Identified for
Protection
The analysis described in this section
was performed to determine
representative avian and mammalian
species of the Great Lakes basin which
are likely to experience significant
exposure to contaminants in aquatic
ecosystems through the food chain. As
a consequence, emphasis is on species
with foraging behaviors and trophic •
levels of their forage sources which
suggest high exposure to contaminants.
Therefore, the wildlife species of
primary concern are piscivorous.
In general, small endbtherms have a
higher ingestion rate relative to body
mass than large endotherms, because
small animals generally have a larger
surface area to volume ratio and lose
proportionately more energy as heat.
This suggests that small animals would
be exposed to contaminants to a greater
degree than large animals, and would
always be at a higher level, of risk.
However, small piscivorous are
generaUy size-limited predators and
feed on smaller fish in a lower trophic
status than larger piscivorous. Since the
concentration of bioaccumulative
pollutants is usually less at lower
trophic levels, it can not be assumed
that small animals have a greater
exposure. Therefore, to. adequately
predict exposure, information on animal
size, food habits, and behavior is
needed. ' ' .
Detorminations were made of , . - -.
representative species that reside in the
Great Lakes basin, based on animal size
(small, medium, and large) and foraging
style. Animals with different foraging
styles may also have different
morphologies and activity patterns that
ultimately influence food or water
ingestion rates and other factors that
determine exposure to contaminants,
1. Selection of Avian Species.,
Piscivorous avian species cartbe ,
classified into three general types of .
foraging styles; raptorial predators,
diving and swimming predators, and
wading,,"sit-and-wait" predators. Some,
species which reside in the GreatLakes
basin and exhibit each.pf these.foraging
styles are listed here:
a. Raptorial: Bald eagle, osprey, : • -••
kingfisher and cc-mmon tern;
b. Diving: Double-crested cormorant,
common loon, common merganser and
redrbroastedmerganser,and :, , ,'.•
c. Wading: Great blue heron and
green-badced heron. •
Exposure data with sufficient detail to
make reasonable exposure estimates for
six Great Lakes basin piscivorous birds
.was obtained: Bald eagle, osprey,
common merganser, common loon,
double-crested cormorant and belted
kingfisher. These species represent two
of the three foraging styles identified.
Analysis of these data indicate that the
ingestion rates are proportional to the
animal mass and the differing foraging .
styles do not contribute to differences in
the ingestion rate. A representative
sample of the variability in bird
exposure to contaminants in water can
be gained by calculating WVs for the
three raptorial species (eagle, osprey
and kmgfisher) which represent the
range and extremes in body siz». The
additional data, since it is only for a
small number of species, was not used
because it could skew-the distribution,.
2. Selection of Mammalian Species.
Two mammals were identified hi the
Great Lakes basin which are piscivorous
and therefore likely to experience
significant exposure to contaminants in
aquatic food chains—the mink and river
otter. The two species have different
body sizes (adult otters are six-to-eight "
times larger than adult mhik), and
different food habits. Wildlife Values
should be calculated "for both mammal
species. The mink has alarger food
ingestion rate relative to body size than
the otter. However, it is unlikely that ••;
mink have a diet that is comprised !
solely of fish from the higher trophic
level as is predicted for me otter.
Therefore, calculatkig Wys for both"
mammals may account for the
variabilijty in exposure that likely occurs
in mammals. . - , .'•'.'}
JB; Derivation of Exposure Parameters
and Body Weights for Species Identified
for Protection , •••,' ;.;..". ••"• ,
1, Bald Eagle (Haliaeetus
leucocephalus). Adult eagles wdgh .
from 3.0 to 6.3 kg with an average adult
weighing about 4.5 kg. (Bortolotti, 1984;
Stabnaster and Gessaman, 1984; Pahner,
1988)v
There have, been several estinaates of
food ingestion rates of-captive and-free-
ranging eagles. Stahnaster and ,'•>•
Gessaman (1982) found that captive .
eagles consumed about 9.2 percent of ,
theirbody mass m fish each day
(approximately 414 g/d).Ho"wever, by
weighing fish carcasses before and alter
they were fed upon by free-ranging
eagles, Stalmaster and Gessaman (1984)
estimated that eagles Wintering on the
Nooksack River, WA, consumed about ^
490 gof fish each day Using models- ;
produced by Gessaman and Stahnaste
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21006 Federal Register / Vol. 58,'No. 72 / Friday, April 16, 1993 / Proposed Rules
(1084), Craig et al. (1988) estimated that
adult eagles wintering along the lower
Connecticut River, CT, consume about
§20 g of food per day. Therefore, it is
assumed that a typical adult eagle
consumes about 500 g of fish per day.
Tha water ingestion rate is derived
from the allomelric equation presented
in appendix D to part 132 and is 0.16
L/d.
2. Osprey (Pandton haliatus). Adult
ospreys weigh from 1.1 kg to 2.0 kg with
a typical adult weighing approximately
1.5 kg (Newell et al., 1987; Palmer,
1988; Poole, 1989).
As reviewed by Palmer (1988), adult
osprey consume 286 kcal/d. Assuming
the metabolizable energy in fish is
approximately 1 kcal/g (Palmer, 1988;
Stalmaster and Gessaman, 1982), osprey
require 286 g of fish per day. A review
of data for European Ospreys,
summarized by Palmer, 1988, suggested
that food requirements were about 300
to 400 g/d. Nagy (1987) presents models
to calculate field metabolic rates (FMRs)
of birds and mammals based on body
weights. The equation for calculating
the FMR (in kcal/bird-d) of anon-
passerine bird is as follows:
log FMR (kcal/bird-d)=O.Q594+0.749 log
Wt (g)
where Wt is in g, wet weight.
The Nagy (1987) model predicts that
osproy require 274 g of fish per day,
assuming osprey weigh 1500 g and the
metabolizable energy in fish is 1 kcal/
g. Also, Newell et el (1987) estimated
that osprey would require 300 g/d
assuming birds consume 20% of their
body weight each day. Therefore, it
appears that a reasonable estimate of
food ingestion rate for adult ospreys is
approximately 300 g/d.
The water ingestion rate is derived
from the allometric equation presented
In appendix D to part 132 of this rule
and is 0.077 L/d.
3. Belted Kingfisher (Ceryle alcyon).
The average adult belted kingfisher
weighs approximately 0.15 kg (Fry,
1980; Dunning, 1984).
Alexander (1977) reviewed the
literature and estimated that adult
Belted Kingfishers may consume up to
50 percent of their body weight in fish
each day. This would equate to
approximately 75 g/d. Since this was an
estimate, the Nagy (1987) model was
applied to calculate the FMR in kcal/d
for a non-passerine bird:
log FMR (kcal/bird-d)=0.0594+0.749 log
Wt(g).
Assuming kingfishers weigh 150 g, ,
and that the metabolizable energy in
fish is 1 kcal/g (Stalmaster and
Gessaman, 1982; Palmer, 1988), the
Nagy model predicts that birds would
require about 50 g/d. Therefore, a
reasonable estimate of the kingfisher
food ingestion rate would be about 75 g
of fish per day.
The water ingestion rate is derived
from the allometric equation presented
in appendix D to part 132 and is 0.017
L/d.
4. Mink (Mustela vison). Adult male
mink range from 0.9 to 1.6 kg, and
females range from 0.6 to 1.1 kg
(Linscombe et al., 1982). Therefore, it is
assumed that an average adult mink has
a body mass of 1.0 kg (see also Newell
et al., 1987).
Estimates of food ingestion rates of
captive mink range from about 12
percent to 16 percent of the adult body
weight per day (Aulerich et al., 1973;
Bleavins and Aulerich, 1981). Therefore,
it will be assumed that a one kg adult
mink consumes about 150 g of food per
day (Aulerich et al., 1973; Newell et al.,
1987).
The water ingestion rate is derived
from the allometric equation presented
in appendix D to part 132 and is 0.099
L/d.
5. River Otter (Lutra canadensis).
Adult otters range from 5 kg to 15 kg,
with a typical adult weighing 8 kg
(Lauhachinda, 1978; Toweill and Tabor,
1982).
ToweiE and Tabor (1982) reviewed
two studies reporting food ingestion
rates of captive otters. North American
otters were reported to require about
700 to 900 g of prepared food each day,
while European otters consumed 900 to
1000 g of live fish each day. Therefore,
.it is assumed that otters consume about
900 g of food per day.
The water ingestion rate is derived
from the allometric equation presented
in appendix D to part 132 and is 0.64
L/d.
C. Derivation of Dietary Trophic Levels
for Species Identified for Protection;
1. Bald Eagle (Haliaeetus
leucocephalus). Bald Eagles are known
to consume a variety of foods including
fish, waterfowl, small mammals, and
carrion. However, if available, fish are
their principal food and large fish may
make up 100 percent of their diet
(Newell et al., 1987; Palmer, 1988; Kozie
and Anderson, 1991). Therefore, it is
assumed that eagles consume only
trophic level 4 fish.
2. Osprey (Pandion haliatus). The diet
of Osprey is almost 100 percent live
fish, concentrating on fish weighing
150-300 g (Palmer, 1988 and Poole,
1989). Therefore, it is assumed that
Osprey are consuming only trophic
level 3 fish.
3. Belted Kingfisher (Ceryle alcyon).
Kingfishers may eat a variety of foods
including fish, amphibians, and insects!
However, small fish are known to
comprise roughly 90 percent of their
total diet (Alexander, 1977). Therefore,
it is assumed that kingfishers have a diet
of only trophic level a fish.
4. Mink (Mustela vison). Mink are
opportunistic carnivores (Linscombe et
at, 1982); however, aquatic organisms
sometimes comprise almost 100 percent
of their diet with fish usually making up
less than 50 percent of their total intake
(Aulerich, 1973; Alexander, 1977;
Linscombe et al,, 1982; Newell et al.,
1987). It is assumed that the diet of
mink foraging in habitats comprising the
shores of the Great Lakes and major
tributaries is made up of trophic level 3
fish.
5. fliVer Otter (Lutra canadensis). The
bulk of the otter's diet is composed of
fish (typically greater than 90 percent)
with other aquatic organisms making up
lesser portions (Toweill and Tabor, .
1982; Newell et al., 1987). It is assumed
that otters consume a diet composed of
50 percent trophic level 3 and 50
percent trophic level 4 fish.
TABLE I.—SENSITIVITY OF SPECIES BASED ON LDj0 Data
Chemical and Species
«*tn: .. . .-. . , , ,,,i , .,.;.. ,. '„• .„. , •..
FiHvou* whistling duck „
Malard , „
pheasant
MoteDaer , „ ,
LDjo (mg/kg)
292
520
659
168 .
18.8-37.5
[95% Con-
fidence Inter-
val]
[22 2-38 4]
[229-1 i210]
[5 00-8 66]
[14 1—200]
-------
Federal Register / Vol. 58, No; 72; / Friday, April 16, 1993 7 Proposed Rides
21007
TABLE I.—SENSITIVITY OF SPECIES BASEPON LDjo Data—Continued
Chemical and Species
Chlordane: \ • -' - \\- •,'"' ".-••' . - . "..:-. : .--,-, .''..;""• "". ' . -.;' ".'- ""•"•-•.
' 'Mallard ....»...,..........„..„....„......; .............. ...,A...!.........i..»...«.;™.....J. ................ 1,200
California Quail , ; ..........; „„ 14.1
Pheasant ...................... —. . •„= „•„ .............. „'..-.' 24.0-727o
DDT.---'. -.-"•-.. ..••".- -.-.•• : •-.":';-•' vV'; "• •• ''•.'.'• •. '••. -':'"• '. .- '- ": :
Bullfrog ...;„, ....'. ; ............ .................. 72,000 ,
Mallard '. ................. ..;.... .'.............. ."..... 72,240
California Quail ...,........:..,..„.. ,.: „......, ......i......;........,, ..; 595
Japanese Quail ... ........................ ......;................™........!;:..;»... 841
Pheasant ..r. ......„............;;.........................„ ......V,. 1,334
Sahdhiil Crane ............... .......;..„.„....!.....„.. .....:. .. 71,200
Rock Dove ...7. •„.;'. .:......•........... ;.... „. 74?,000
Dleldrin: ,. : • ' .; ; '.'.-.
, -" Canada Goose !....„... ........ ..:....... ...;.... ..../......I <141
^.Fulvous Whistling Duck .........; ................................... .;. 100-200
= Mallard „......; :...... 381
• California Quail ,....;....; ., 8.78
Japanese Quail .-. „.......:.:.„„. !...„'.„...; 69.7
Pheasant .....>.... ......................; ...... 79.0
Chukar .„ ...' .'............................ .;.. 25.3
Gray Partridge .................... ......: .'. 8.84
Rock Dove .......... ...„..., ., ........ .; 26.6
House Sparrow .,.............;......„..........„„„..„..„....„.„.... ;. ......... 47.6
. Mule Deer ...„,..;. ,.;....... .....:... ...L..-........J.-.;. . ........ 75-150
Domestic Goat ......:. ...„ ...^....;.......... 10f>-200
Endrih:' . ".'.. •. "*'-• •' -' .'..-••. .-. .,, _.": '-' . . ,., ' ',- '" '' - - ;'-'.' ". '• "
Mallard ...'....! .;......,. ^.,.....»i... .„„ 5.64
•- Sharp Tailed Grouse ;.„.......'..,:...... ;... . ...... ...........'................L.....,....;.: .....". „. 1.06
California Quail ..„.........„., ;.,..,.......... ,.....;........ ......i 1.19
' Pheasant* .....;............; ...,...„. ...„.........,.....;. ; ........;...„.....! .„......„.....•..„„... i,7S /
Rock Dove 1................. ;.., ......„.....;.. ; ...„ 2.6-5.0 '
Mule Deer......;......:...... ,,.;....; .....^......«. , ,.4.;..,..... 6.25-12.5
Domestic Goat » ~. ...,......„,.„ 25.0-50,0 ,
Hexachlorobenzene: , • ... • -..'
Mallard ....„.,......! ..'........;.„... 7i,4t4
Pheasant ..................... ............... 118
Parathlon:. .•_'..'' - '•[•'..
Fulvous Whistling Duck .:....... '•. ...........„„„ 0.125-0.250
Mallard —........;........ ........... .„„.„.. ^2.40
Mallard ....:............;....................... ....,...,.;i.......;.......i. .„.........;. ....;... ...; ..„ 1.90
- Mallard ..........-.:. ..........».............^ .'.........„. 2.34 '
Mallard...;....... ..........^«.....;.....l......:..™... :.........:...;... ;.................. .... .. 1.44
: .• Mallard ;.......;... .,....„;......... ..„.....„• ;............ ....... ; . i 44 .
. Mallard Duckling (MM) .,..«..„ .„...:.... .-„ 0.898
Sharp Tailed Grouse .,... .......„......,......;..„....„„ „...„.„.. 5.66
California Quail '.......... 16.9
Japanese Quail ........! .................— ..„.'..........„..... ...„„ 5.95
Ptieasant I.™.............;....,.........:.. ....;.........;..„;...„„....„ 12.4
Pheasant .•..„..... .„..„. ;........ ...................; >24.0
;Chukar .......:....;..,.................... .....,^......\ 24.0
Gray Partridge ..; ..:..... '.....'.. ...-......: „........„ 16.0
' Rock Dove.'..;..:....-...........; .....;..........„......; ..„ ....................I.......™.................. 2.52
House Sparrow :. ....: 3.36 '.•'-.
Mule Deer „ 22.0-44.0
Domestic Goat ..—..,.;.,........i....... „ .;.„ 28.0-56.0
PCS (Aroclpr 1242):. :
. Mallard Duck .,—..............—......,.,.....,...........; 2,098
Pheasant ...i 2078
Mink ,....".....„.. .".:.,.....„„.„..„„.;, ........„.........".:,. ...;.,..... .'....•„...„.„..„„ ^^......;...;......... "1*0-8.6
Ferret ..............I..!...'...... ...... ^.....-........««...... ;.....;... 1.. >20
: : Rat...........'.. ...........'...„.........,................ » ...'. .„.....,..' ..........i......................'.!........ 0.8-11.0
Rabbit ... . ......;..... „. .i........... .„ ...... . 8.7 .
.Temephos: . ': , -.-''".. '-.."'•. :• .
- Bullfrog ....r...... ...:.......^...™...l ;..„..; .,., ;......v..... >2,000 ,
Mallard ...; :......... ............;.„ 79.4
:.' , California Quail ..,.................^.,......JW,.. 18.9
. Japanese Quail ] „...,..... B4.1
. . ^Pheasant ., ......,.,........:,.,.........,..;.l....,..............«.«........!. «.!.,.......;..«...'...;.........i...."...!.....w.l....i,. 35.4
.',.-' Chukar ....„...........'. ........,.;...^L;.,...^...........<....,,........I.»,..^^ ....„.,....„„. 24d ,
RQCk Dove ........;............^.....^'...«..........«.i.«...........;.................;,.. SO.t
LDso(mg/kg)
[95% Con-
fidence -Inter-.
:••• val]
[954-1,510}
(9.14-21.7V
[430-825]
[607-1.170]
[894-1,990]
[6.47-11.9]
[40.0-121]
[21.6-289
[15.2-42.2
[1.24-62.8
[19.2-36.9
[34.3-66.0
[2.71-11.7]
[0.552-2.04
[0.857-1.65
[1.12-2.83;
[93.6-148]
[1.67-4.01]
[1.37-2.64
[1.88-2.92
[1.13-1.83
[1.16-1.80
[0.770-1.05!
[3.46-^9.24
[12.2-23.5
[3.38-10.5
: [10,1-15.2
[16.8-34^;
[4.00-64.0'
[1.82-3.50
[2.43-4.66
[38.5-163]
[15.0-23.8j
[60.6-116
[25.5-49.0
"•'''
,
[16.7-150
-------
21008
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
TABLE I,—SENSITIVITY OF SPECIES BASED ON LD3o p
Chemical and Species
Housa Sparrow ."....... ,.
2,3,7,8-TCDD:
RUt , ..
Rhosus Monkey •
Don . ,
M
Sbmp Tsllod Qrouso ....» ...» — «. • »»•
Bobwhita * , . * •• •
Hom*d urk .............;;.;.:.: ...:..:.....„................ ...........
Dorosstfa Goat •
LDso (mg/kg)
35.4
0.6-2 H<5/kg
22-45 ng/kg
<70 fig/kg
1 00-200 ng/kg
114-284 jig/kg
115|ig/kg
1,157-5,051 jig/kg
99.0
30.8
70.7
19.9
85.5
23.7
40.0
23.7
100-316
581
139-240
>160
[95% Con-
fidence Inter-
val]
[8.85-141
[37.2-264]
[23.3-40.6]
[37.6-133]
[14.1-28.2]
[59.3-123]
[11.9-47.4]
[20.0-80.0]
[20.0-28.3]
[425-794]
Adopted from Bsler 1986a,b and Hudson, et al. 1984.
TABLE II.—TOXICITY OF ORGANOMERCURY
COMPOUNDS TO SELECTED MAMMALIAN
SPECIES
Species
Doa
Cat
pfg „ ,
Rhesus Monkey
MW<
Rivsr Otter.
Dose (mg/
kg)
0.1-0.25
0.25
0.5
0.5
1.0
>2.0
Effect
Stillbirths.
Death.
Stillbirths.
Maternal
Toxlcity.
Death.
Death,
Adopted from Eisler 1987.
VI. References
Alexander, G. 1977. Food of vertebrate
predators of trout waters In north central
lower Michigan. Michigan Academician.
10:181-195.
Aulcrfch, R. J., R. K. Ringer and S.
twamoto. 1973. Reproductive failure and
mortality in mink fad on Great Lakes fish. J.
Raprod. Pert. (Suppl.) 19:365-376.
Bicavins, M. R. and R. J. Aulerich. 1981.
Feed consumption and food passage in mink
(Mustola vison) and European ferrets
(Mustola putorius furo). Lab. Animal Sci.
31:268-269.
Bortolottl, G. R. 1984. Sexual size
dimorphism and age-related size variation in
bold eagles. J. Wildl. Manage. 48:72-81.
Older in, W. A., and E. J. Braun. 1983.
Scaling of osmotic regulation in mammals
and birds. American Journal of Physiology.
244:601-606.
Orals. R. J., E. S. Mitchell and J. E.
Mitchell. 1988. Time and energy budgets of
bald eagles wintering along the Connecticut
River. J. Field Omithol. 59:22-32.
Dourson, M. L. and J. F. Stara. 1983.
Regulatory history and experimental support
of uncertainty (safety) factors. Regulatory
Toxicology and Pharmacology. 3:224.
Dunning, J. B. 1984. Body weights of 686
North American birds, Monograph #1,
Western Bird Banding Association.
Eisler, R. 1986a. Dioxin hazards to fish,
wildlife, and invertebrates: a synoptic
review. U.S. Fish and Wildlife Service
Biological Report. 85(1.8): 37pp.
Eisler, R. 1986b. Polychlorinated biphehyl
hazards to fish, wildlife, and invertebrates: a
synoptic review. U.S. Fish and Wildlife
Service. Biological Report. 85(1.7): 72 pp.'
Eisler, R. 1987.-Mercury hazard to fish,
wildlife and invertebrates: a synoptic review.
U.S. Fish and Wildlife Service Biological
Report. 85(1.10): 90pp.
Fry, C. 1980. The evolutionary biology of
kingfishers (Alcedinidea). In: The Living
Bird, 1979-1980. The Laboratbry of
Ornithology, Cornell Univ., Ithaca, pp. 113-
160.
Great Lakes Water Quality Initiative.
Appendix A: Uncertainty Factors. HI Great
Lakes Water Quality Criteria Initiative
Technical Support Document for Human
Health Criteria and Values. NTIS #PB93-
15468. ERIC: 3940.
Hudson, R. H., R. K. Tucker, and M. A.
Haegele. 1984. Handbook of toxicity of
pesticides to wildlife, U.S. Fish and Wildlife
Service, Resource Publication #153, 90 pp.
Kozie, K. D. and R. K. Anderson. 1991.
Productivity, diet, and environmental
contaminants in bald eagles nesting near the
Wisconsin shoreline of Lake Superior. Arch.
Environ. Contain. Toxicol. 20:41-48.
Lauhachinda, V. 1978. Life history of the
river otter in Alabama with emphasis "on food
habits. Ph.D. dissertation. University of
Alabama, Auburn, AL. 169 pp.
Linscombe, G., N. Kinler and R. Aulerich.
1982. Mink. In: J. Chapman and G.
Feldhamer (eds.), Wild Mammals of North ,
America: Biology, management and ,
economics. John Hopkins Univ. Press,
Baltimore, pp. 629-643.
Nagy, K. A. 1987. Field metabolic rate and
food requirement scaling in mammals and
birds. Ecological Monographs. 57(2):111-128
National Institute for Occupational Safety
and Health. Latest edition. Registry of Toxic
Effects of Chemical Substances (available •
only on microfiche or as an electronic data
base). Cincinnati, OH.
Newell, A. J., D. W. Johnson and L. K.
Allen. 1987. Niagara River biota
contamination project: Fish flesh criteria for
piscivorous wildlife. New York State,
Division of Environmental Contaminants.
Technical Report 87-3.
Palmer, R. S. Editor. 1988. Handbook of
North American birds: Volume 4. Yale
University Press. 433 pp.
Poole, A. F. 1989. Ospreys: A natural and
unnatural history. Cambridge, MA:
Cambridge University Press.
Registry of Toxic Effects of Chemical
Substances. Latest edition. National Institute
for Occupational Safety and Health.
Cincinnati, OH.
Stalmaster, M. V. and J. A. Gessaman.
1982. Food consumption and energy
requirements of captive bald eagles. J. Wildl.
Manage. 46:646-654. '
„ Stalmaster, ,M. V. and J. A. Gessaman.
1984. Ecological energetics and foraging
behavior of overwintering bald eagles. Ecol.
Monogr. 54:407-428.
Stephen, C. E., D. I. Mount, D. J. Hansen,
J. H. Gentile, G. A. Chapman, and W. A.
Brungs. 1985. Guidelines for deriving
numerical national water quality fcriteria'fof
the protection of aquatic organisms and their
uses. PB85-227049. National Technical
Information Service. Springfield, VA.
Stokinger, H.E! 1972. Concepts of "
thresholds in. standard setting. Arch. Environ.
Health. 25:153-157.
-------
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules 21009
Toweill, D. E. and J. E. Tabor. J982. River
otter. In: J. Chapman and G. Feldhammer
(eds.), Wild Mammals of North America.
John Hopkins Univ. Press, Baltimore, pp.
688-703. .-...-
U.S. EPA. 1980. Appendix C. Guidelines
and Methodology Used in the Preparation'of "
Health Effect AssessmentiChapters of the
Consent Decree Water Criteria Documents, .
pp, 79347-79357 in Water Quality Criteria
Documents; Availability. 45 FR 79318-
79378. Friday, November 28,1980. ,
U.S. EPA. 1985. Section V.C. Evaluation of
Health Effects and Determination of RMCLs
pp. 46944-46950 in National Primary
Drinking Water Regulations; Synthetic
Organic Chemicals; Inorganic Chemicals and
Microorganisms. 50 FR 46936-^4702:2.
Wednesday November 13,1985.
i, and D.D. McCollister, 1963.
tip between short-and long-term
studies in designing an effective toxicity test.
Agric. Food Chem. 11:486-491. '-'
List of Subjects
40 CFR Part 122
Administrative practice and
procedure, Confidential business
information, Great Lakes, Hazardous
substances/ Reporting and
recordkeeping requirements, Water
pollution control.
40 CFR Part-123
' Admii;istratiye practice and
procedure, Confidential business
information, Great Lakes, Hazardous
-substances, Indians-lands,...
Intergovernmental relations, Penalties,
Reporting and recordkeeping
requirements, Water pollution control.
40CFRPartl31
, Great Lakes^Reporfing and
recordkeeping requirements, Water
pollution control.
.40 CFR Part 132
Administrative practice and
procedure, Great Lakes, Indians-lands,
Intergovernmental relations, Reporting
and recordkeeping requirements, Water
pollution control.
Dated: March 30,1993.'
Carol M. Browner, , , ;
Administrator.
For the reasons set forth in the
preamble, EPA proposes to amend 40
CFR.parts 122,123, and 13.1, and add
part 132 as follows:
PART 122—EPA ADMINISTERED
PERMJT PROGRAMS: THE NATIONAL
POLLUTANT DISCHARGE
ELIMINATION SYSTEM ; ;
l.-The authority citation for part, 122
, continues to read as follows: .
Authority: the Clean Water Act, 33 U.S.C.
:1251etse
-------
Federal Register / Vol. 58, No. 72 7 Friday, April 16, 1993 / Proposed Rules
11. Section 131.21 is amended by
revising paragraph (b) to read as follows:
S131.21 EPA review and approval of water
quality standards.
» * * * *
(b) The Regional Administrator's
approval or disapproval of a State water
quality standard shall he based on the
requirements of the Act as described in
§§ 131.5 and 131.6, and, with respect to
Great Lakes States or Tribes (as defined
in 40 CFR 132.2), 40 CFR part 132.
* * * * , * -,'
12. Part 132 is proposed to be added
as follows;
PART 132—WATER QUALITY
GUIDANCE FOR THE GREAT LAKES
SYSTEM
Sec.
132.1 Scope, purpose, and availability of
documents.
132.2 Definitions.
132,3 Adoption of criteria.
132.4 State adoption and application of
methodologies, policies and procedures.
132.5 Procedures for adoption and EPA
review.
132,6 Application of part 132 requirements
in Great Lakes States and Tribes.
Table* to Part 132
Appendix A to Part 132—Great Lakes Water
Quality Initiative Methodologies for
Development of Aquatic Life Criteria
and Values
Appendix B (o Fart 132—Great Lakes Water
Quality Initiative Methodology for
Development of Bioaccumulation
Factors
Appendix C to Part 132—Great Lakes Water
Quality Initiative Procedure for
Development of Human Health Criteria
and Values
Appendix D to Part 132—Great Lakes Water
Quality Initiative Methodology for the
Development of VVildlifa Criteria and
Values
Appendix E to Part 132—Great Lakes Water
Quality Initiative Antidegradation
Policy
Appendix t to Part 132—Great Lakes Water
Quality Initiative Implementation
Procedures
Authority: 33 U.S.C. 1251 etseq.
§ 132.1 Scop*, purpose, and availability of
documents.
(a) This part constitutes the Water
Quality Guidance for the Great Lakes
System required by section 118(c)(2) of
the Clean Water Act (33 U.S.C. 1251 ei
seo.) as amended by the Great Lakes
Critical Programs Act of 1990 (Pub. L.
101-598,104 Stat 3000 et seg.). This
Guidance specifies minimum water
quality standards, antidegradation
policies, and implementation
procedures for the Great Lakes System
to protect human health/aquatic life,
and wildlife.
(b) Certain documents referenced in
the appendixes to this part with a •
designation of NTIS and/or ERIC are
available for a fee upon written request
to the National Technical Information
Center (NTIS), U.S. Department of
Commerce, 5285 Port Royal Road,
Springfield, VA 22161. Alternatively,
copies may be obtained for a fee upon -
written request to the Educational
Resources Information Center/
Clearinghouse for Science, Mathematics,
and Environmental Education (ERIC/
CSMEE), 1200 Chambers Road, Room
310, Columbus, Ohio 43212. When
ordering, please include the NTIS or
ERIC/CSMEE accession number.
(c) [Reserved]
[Note: The reporting or recordkeeping
information provisions in this proposed rule
have been submitted to the Office of
Management and Budget under section
3504(b) of the Paperwork Reduction Act of
1980,44 U.S.C. 3501 ef seq. (ICR number
1639.01). When the reporting requirements
have been approved by OMB, the text of this
paragraph will be added in the final rule.]
§132.2 Definition*.
The following definitions applvjn
this part. Terms not defined in this
section have the meaning given'by the
Clean Water Act or EPA implementing
regulations.
Acceptable daily exposure (ADE) is an
estimate of the maximum daily dose of
a substance which is not expected to -
result in adverse effects to the general
human population, including sensitive
subgroups.
Acute toxic unit (TUa) is 100/LC50
where the LC50 is expressed as a
percent.
Acute toxicityis an,adverse effect hi
an organism as a result of exposure to
a toxicant for a relatively short period of
time relative to the organism's natural
life span. '
Acute-chronic ratio (ACR) is the ratio
of the acute toxicity of an effluent or a
toxicant to its chronic toxicity. The ACR
.is used as a factor for estimating chronic
toxicity on the basis of acute toxicity
data, or for estimating acute toxicity on
the basis of chronic toxicity data.
Adverse effect is any deleterious effect
to organisms due to exposure to a
substance. This includes effects which
are or may become debilitating, harmful
or toxic to the normal functions of the
organism, but does not include non-
harmful effects such as tissue '
discoloration alone or the induction of
enzymes involved in the metabolism of
the substance.
Allowable dilution flow (Qaj) is the
portion of the stream design flow used
in developing the wasteload allocation
for sources regulated by the National
Pollution Discharge Elimination System
(NPDES) program. The Qad is calculated
in procedure B3, section D.S.a.ii, of
appendix F of this part.
Bioaccumulation is the uptake and
retention of a substance by an aquatic
organism from its surrounding media
and food,
Bioaccum ulation factor (BAF) is the
ratio (hi L/kg) of the substance's
concentration in tissue of aquatic
• organisms resulting from .•
bioaccumulation, versus its
concentration in ambient water.
Bioaccumulative chemical of concern
(BCC) is any chemical which, upon
entering the surface waters, by itself or
as its toxic transformation product,
bioaccumulates in aquatic organisms by
a human health bioaccumulation factor
greater than 1000, after considering
metabolism and other physicochemical
properties that might enhance or inhibit
bioaccumulation, in accordance with
the methodology in appendix B of this
part. BCCs include, but are not limited
to, the pollutants identified as BCCs in
part A of Table 6 of this part. . ; .
Bioconcentration is the uptake and
retention of a substance by an aquatic
organism from the surrounding water
only through gill membranes or other
external body surfaces.
Bioconcentration factor (BCF) is the
. ratio of the substance's concentration in
tissue of aquatic organisms resulting
from bioconcentration versus its
concentration in water.
Biomagnification is the transfer and
step-wise increase in bioaccumulation
of a chemical in organisms through
successive trophic levels.
Carcinogen is a substance which ^
causes an increased.incidence of benign
or malignant neoplasms, or substantially
decreases the time to develop
neoplasms, in animals or humans.
Chronic toxic unit (TUC) is 100/NOEC,
where the NOEC is expressed as a
percent.
Chronic toxicityis an adverse effect in
an organism as a result of exposure to
a toxicant for a major portion of time
relative to the organism's natural life
span.
Compliance evaluation level (CEL) is
the level at which compliance with a
water quality-based effluent limitation
in an NPDES permit is assessed. It is the
minimum level, when the water quality-
based effluent limit is less than the "
minimum level. Otherwise, it is the
water quality-based effluent limn.
Connecting channels of the Great
Lakes are the Saint Mary's River, Saint
Clair River, Detroit River, Niagara River,
and Saint Lawrence River to the
Canadian Border.
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> Fbderal Register / Vol. 58, No; 72 /Friday, April 16,1993 / feoposed
21011
Criterion continuous concentration
(CCC) is the lower of the Final Plant
Value or the Final Chronic Value. It is
the highest instream concentration of a
material to which aquatic organisms can
be exposed indefinitely without causing
unacceptable effect -,--.'
- Criterion maximum concentration
(CMC)[is one half the FAV. Itis the'
highest instream concentration of a
material to which aquatic organisms can
be'exposed for a brief period of time
without causing an unacceptable acute
effect
Depuration is the loss of a substance
from an aquatic organism. .
Detection level is the minimum
concentration of an analyte (substance)
that can be measured and reported with
a 99 percent confidence that the analyte
concentration is greater than zero as
determinedby the procedure set forth at
^appendix B of 4p CFR part 136.
Dilution fraction is the factor wlu'ch,
when multiplied by the stream design
flow, determines the allowable dilution
flow (Qad). The dilution fraction is
calculated as detailed in section
D.S.a.iii. of procedure B3 in appendixF
of this part
EC50 is the concentration of a test
material at which 50 percent of the
exposed organisms exhibit an
observable adverse effect (such as death,
immobilization, or serious •
incapacitation) during a specified time
jperlod. •
- Existing dischargee is any source
which is neither a new source,as >
defined by 40 CFR 122.2 nor a new
discharge as defined by 40 CFR 122.2.
. - • Existing uses are those uses actually
attained in the water body on or alter
November 28,1975, whether or not they
are included in the water quality
standards. ,
- Federal Indian Reservation, Indian
Reservation, or Reservation means all
land within the limits of any Indian
reservation under the jurisdiction of the
United States Government,
notwithstanding the issuance of any •
patent, andincluding rights-pf-way
ruhninff through the reservation.
- Finalacute value (FAV) is an.esllmate
of the concentration of a material such
- that 95 percent of the genera {with
which acceptable acute toxicjty tests
have been conducted on the material}
• have higher acute toxicity values.The
. calculated FAV may be lowered to be
equal to the Species Mean Acute Value
of a commercially or recreationally
important species of the Great Lakes
System.' ' • ;
Final chronic value (FCV) is an
estimate of the concentration of a
'material such that 95 percent «f the '-
genera (with which acceptable-chronic
toxicity tests have been conducted on
the material) have higher chronic
toxicity values. Alternatively, the FCV
may be determined by dividing the FAV
by an acute-chronic ratio. The
calculated FCV may be lowered to be
equal to the Species Mean Chronic
Value of a commercially or
recreationally important species of the
Great Lakes System.
Final plant value (FPV) is the result
of a 96-hour test conducted with an alga
or chronic test conducted with an
aquatic vascular plant
Genus mean acute value (GMAVJis
the geometric mean of the Species Mean
Acute Values for the genus.
Genus mean chrome value (GMCV) is
the geometric mean of the Species Mean
Chronic Values for the genus.
Great Lakes means Lake Ontario, Lake
Erie, Lake Huron (including Lake St
Clair), Lake Michigan, and Lake
Superior; and the connecting channels
(Saint Mary's River, Saint Clair River,
Detroit River, Niagara River, and Saint ,
Lawrence River to the Canadian Border).
Great Lakes States and Great Lakes
Tribes, or Great Lakes States and Tribes
..means {he States of Illinois, Indiana,
Michigan, Minnesota, New York, Ohio,
Pennsylvania, and Wisconsin, and any
Indian tribe as defined in this part
which is located in whole or In part
within the drainage basin of the Great
Lakes, and that EPA has determined
qualifies under section 518 of the Clean
Water Act to administer programs under
sections 303 (see 40 CFR 131.8) and/of
402 of the Clean Water Act.
Great Lakes System means all the
streams, rivers, lakes and other bodies of
water within the drainage basin of the ,
Great Lakes.
• Human cancer criterion (HOC) is a
Human Cancer Value (HC V) for a• ,
pollutant that meets the minimum data
requirements for Tier I specified in
appendix G of this part -
•' Human cancer value (HGV) is the '
maximum ambient water concentration
of a substance at or below which a,
lifetime of exposure from either: ^ -
drmking the water, consuming fish from
the water, and water-related recreation
activities; or consuming fish from tlia
water, «nd water related recreation
activities, will represent a plausible ,
upper bound risk of contracting cancer
of one in lOO.OGQusing the exposure
assumptions specified in the
methodologies for the development of -
Human Health Criteria and Values in
appendix C pf this part •
• Human noncancer criterion (HNC) is
a Human Noncancer Value (HNV) for a
pollutant that meets the minimum data
requirements for Tier I specified in
appendix C of this part;-
Human noncancer value (HNV) is the
maximum ambient water concentration
of a substance at or belowr which
adverse noncancer effects are not likely
to occur in the human population from
lifetime exposure via either: drinking
the water, consuming fish.from the •
water, and water-related recreation
activities; or consuming fish from the
water, and water-related recreation
activities using the Human Health
Criteria and Values in appendix C of
tills part. . ?
Indian Tribe or Tribe meansiany -
IndianTribe, hand, group, or
community recognized by the Secretary
of the Interior and exercising
governmental authority over a Federal
Indian reservation. '
LC50 is the concentration of a test
material at which 50 percent of the
exposed organisms die during a
specified time period. ,
Linear multi-stage model is a.
conservative mathematical model for
cancer risk assessment This model fits
linear dose-response curves to low
doses. It is consistent with a no-
threshold model of carcinogenesis, i.e.,
exposure to even a very small amount'
of the substance produces a finite
increased risk of cancer.
Load allocation (LA) is the portion of-
a receiving water's loading capacity that
is attributed either to one of its existing
or future non-point sources or to natural
background sources, as more fully
defined at 40 CFR 130.2(g). Nonpoint
sources include: in-place contaminants,
direct wet and dry deposition,
groundwater inflow, andoverland
runoff.; . >• -"- •- ./-... • •••. • -' •'' --• ••
Loading capacity is the greatest
amount of loading that a water can
receive without violating water quality
standards.
Lowest observed adverse effect level
(LOAELjisthe lowest tested dose or
'concentration of a substance which
resulted in an observed adverse effect in
exposed test organisms when all higher
doses or concentrations resulted in the
same or more severe effects.
Minimumlevel(ML) is the level at
which the analytical system gives ''.-•-
recognizable spectra and acceptable
- calibration points; ,It is based upon
interlaboratory analyses for the analyte • :"
in the matrix of concern;
No observed adverse effect level •;
(NOAELjis the highest tested dose or
concentration of a substance which
resulted in no observed adverse effect in
exposed, test organisms when .all lower
levels resulted in no observed adverse
effect . " • ;';" :•" " ' ..-";..'';-- '' '• •' "• -
No observed effect concentration
(NOEC) is the highest tested
concentration of an «ffluent or a
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Federal Register / Vol. 58, No.- 72 / Friday, April 16, 1993 / Proposed Rules
toxicant at which, no adverse effects are
observed on the aquatic test organisms,
at a specific time of observation, when
all lower levels resulted in no observed
effect
Noncarcinogen is a substance which
is not classified as a known, probable,
or possible human carcinogen according
to the weight-of-evidence assessment.
Octanol/water partition coefficient
(KnJ is the ratio, at equilibrium, of the
concentration of a substance in the
octanol phase to its concentration in the
aqueous phase in a two-phase octanol/
water system.
Open waters of the Great Lakes means
all of the waters within Lake Erie, Lake
Huron (including Lake St. Glair), Lake
Michigan, Lake Ontario, and Lake
Superior lakeward from a line drawn
across the mouth of tributaries to the
Lakes, including all waters enclosed by
constructed breakwaters, but not
including the connecting channels.
Quantification level is a measurement
of the concentration of a chemical
obtained by using a specified laboratory
procedure, at a specified concentration
above the detection level. It is
considered the lowest concentration at
which a particular substance can be
quantitatively measured using a
specified laboratory procedure.
Quantitative structure activity
relationship (QSAR) or structure activity
relationship (SAR) is a mathematical
relationship between a property
(activity) of a chemical and a number of
descriptors of the chemical. These
descriptors are chemical or physical
characteristics obtained experimentally
or from the structure of the chemical.
Reasonable potential is where an
effluent is projected or calculated to
cause or contribute to an excursion
above any water quality standard,
including State narrative criteria for
water, by using procedures which at a
minimum account for existing controls
on point and nonpoint sources of
pollution, the variability of the pollutant
or pollutant parameter in the effluent,
the sensitivity of the species to toxicity
testing (when evaluating whole effluent
toxicity), and where appropriate the
dilution of the effluent In the receiving
water.
Relative source contribution (RSC) is
the factor (percentage) used in
calculating a HNV or HNC to account
for all sources of exposure to a
contaminant. The RSC reflects the
percent of total exposure which can be
attributed to surface water through
water intake and fish consumption.
Risk associated dose (RADjis a dose
of a known or presumed carcinogenic
substance in rnilligrams/kilogram/day
which, over a lifetime of exposure is
calculated to be associated with a
plausible upper-bound incremental
cancer risk equal to one hi 100,000..
Slope factor, also known as qi*, is the
incremental rate of cancer development
calculated through use of a linear
multistage model. It is expressed in (mg/
kg)/day of exposure to the chemical in
question.
Species mean acute value (SMAV) is
the geometric mean of the results of all
flow-through acute toxicity tests (LC50)
in which the concentrations of test
material were measured. For a species
for which no such result is available, the
SMAV should be calculated as the
geometric mean of all available acute
values. ' •
Species mean chronic value (SMCV)
is the geometric mean of the results of
aH flow-through chronic toxicity tests in
which the concentrations of test
material were measured. For a species
for which no such result is available, the
SMCV Should be calculated as the
geometric mean of all available chronic
values.
Steady-state BAF/BCFis a BAF or
BCF that does not change substantially
over time. It is the BAF or BCF that
exists when uptake and depuration are
equal.
Stream design flow is the stream flow
that represents critical conditions,
upstream of the source, for protection of
aquatic life, human health, and wildlife.
Superlipophilic chemicals are
chemicals with a very strong affinity for
lipids, having a log Kow greater than 6.5.
Threatened or endangered species are
those species that are listed as
threatened or endangered under the
Federal Endangered Species Act.
Threshold effect is an effect of a
substance for which there is a
theoretical or empirically established
(Jose or concentration below which the
effect does not occur.
Tier I criteria are numeric values
derived by use of the Tier I
methodologies hi appendixes A, C and
appendix B of this part, and the
procedures in appendix F of this part,
that either have oeen adopted as
numeric criteria into a water quality
standard or are used to implement
narrative water quality criteria.
Tier II vajues are numeric values
derived by use of the Tier n
methodologies in appendixes A, C and
D of this part, the methodology in
appendix B of this part, and the
procedures in appendix F of this part,
that are used to implement narrative
water quality criteria.
Total maximum daily load (TMDL) is
the sum of the individual wastelpad
allocations for point sources and load
allocations for nonpoint sources and
natural background, as more fully
defined at 40 CFR 130.2(i)'. A TMDL sets
and allocates the maximum amount of
a pollutant which may be introduced
into a water body and still assure
attainment and maintenance of water
quality standards.
Tributaries of the Great Lakes System
means,all waters of the Great Lakes
System that are not open waters of the
Great Lakes, or connecting channels.
Uncertainty factor (UF) is one of
several, generally 10-fold, factors used
in operationally deriving criteria from
experimental data.
Uptake is the sorption of a substance
into or onto an aquatic organism.
Wasteload allocation (WLA) is the.
portion of a receiving water's loading
capacity that is allocated to one of its
existing or future point sources of
pollution, as more fully defined at 40
CFR130.2(h).
Wet weather point source is a point
source which is either,an outfall from a
municipal separate storm sewer as
defined at 40 CFR 122.26(b)(?), a storm
water discharge associated with
industrial activity as defined at 40 CFR
122.26(b)(14), or a combined sewer
overflow. A combined sewer overflow is
a flow from a combined sewer in excess
of the interceptor or regulator capacity
which is discharged into a receiving
water body without going to a publicly
owned treatment works. Combined
sewer overflows occur prior to the
headworks of a treatment facility. A
storm water discharge associated with
industrial activity which is mixed with
process wastewater shall not be
considered a wet-weather point source.
§132.3 Adoption of criteria.
The Great Lakes States and Tribes
shall adopt numeric water quality
criteria for the purposes of section
303(c) of the Clean Water Act applicable
to waters of the Great Lakes System in
accordance with § 132.4(d) that are
equal to or more restrictive than:
(a) The acute water quality criteria for
protection of aquatic life in Table 1 of
this part, or a site-specific modification
thereof in accordance with procedure 1
of appendix F of this part;
(b) The chronic water quality criteria
for protection of aquatic life in Table 2
of this part, or a site-specific >
modification thereof in accordance with
procedure 1 of appendix F of.ihis^partu
(c) The water quality criteria for
protection of human health in Table 3
of this part, or a site-specific
modification thereof in accordance with
procedure 1 of appendix F of this part;
and
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Federal Register /VojL 58, No. 72 / Friday, April 16, 1993 /Proposed Rules
21013
(d) The water quah'fy criteria for
protection of wildlife in Table 4 of this
part, or a site-specific modification ,
thereof in accordance wijii procedure 1
of appendix F of this part
§132.4 State adoption and application of.
methodologies, policies and procedures.
{a)The Great Lakes States and Tribes
shall adopt requirements applicable to
waters of theGreat Lakes System for the.
purposes of sections 118,303,^ and 402
of the Clean Water Act that are
consistent with:
(1) The definitions in §132.2;
(2) The Methodologies for "
Development of Aquatic Life Criteria
and Values in appendix A of this part;
(3) The Methodology for Development
of Bioaccumulation Factors in appendix
B of this part;
, (4) The Methodologies for
Development of Human Health Crjiteria
and Values in appendix C of this piart;
<5) The Methodologies for
Development of Wildlife Criteria and
Values in appendix D of this part;
(6) The Antidegradation Policy in
appendix E of this part; and
(7) The Implementation Procedures in
appendix F of this part
(b) Except as provided in paragraphs
{g) and (h) of this section, the Great
Lakes States and Tribes shall use the
methodologies designated as Tier i;
methodologies in appendixes A, C, and:
D of this part, the methodology in
appendix B of this part, and fee
procedures in appendix F of this part
when adopting or revising numeric
water quality criteria for the purposes of
section 303(c) of the Clean Water Act for
the Great Lakes System. -
• (c) Except as provided La paragraphs
(gj and (h) of this section, the Great
Lakes States and Tribes shall apply the
methodologies designated as Tier I and
1 Tier n methodologies in appendixes A,
C, and D of this part, the methodology
in appendix B of this part, and the
procedures in appendix F of this part to
- develop numeric values when
implementing narrative water quality
criteria adopted for purposes of section
303(c) of the Clean Water Act.
(d) The water quality criteria and -
values adopted or developed pursuant
to paragraphs (a) through (c) of this
section shall apply as follows: • -
jl) The acute water quality criteria
and values for the protection of aquatic
life, or site-specific modifications
thereof,'shall apply to all waters of the
Great Lakes System.
(2) The chronic water quality criteria
and values for the protection of aquatic
life, or site-specific modifications
thereof, shall apply to all waters of the
Great Lakes System.
{3) The water quality criteria and •
values for protection of human health,
orsiterspecific modifications thereof,
shall apply as follows:
(i) Criteria and values derived as
HCVrDrinking and HNV-Drinking shall
apply to the Open Waters of the Great
Lakes, all connecting channels of &e
Great Lakes, and all other waters of the
Great Lakes System that have been
designated as public water supplies by
any State or Tribe in accordance with 40
GFR131.1Q.
(ii) Criteria and values derived as
HCV-Nondrinking and HNV-
Nondrinking shall apply to all waters of
the Great Lakes System other than those
in paragraph (d)(3)(i) of this section.
(4)I Criteria and values for protection
of wildlife, or site-specific modifications
thereof, shall apply to all waters of the.
Great Lakes System.
(e) The Great Lakes States and Tribes
shall apply the implementation
procedures adopted pursuant to
§ 132.4{a){7) for all applicable purposes
under the Glean Water Act, including
developing total maximum daily loads
for the purposes of section 303{d) and
water quality-based effluent limits for
the purposes of section 402, in
establishing controls on the discharge of
any pollutant to the Great Lakes System
by any point source with the following
exceptions: .
(1) The Great Lakes States and Tribes
are not required to apply these
implementation procedures to ,
establishing controls on the discharge of
any pollutant by a wet weather point
source. Any adopted implementation
procedures shall conform with all
applicable Federal, State and Tribal
requirements. •
(2) The Great Lakes States and Tribes
may, but are not required to, apply
procedures 1,2,3,4,5,7,8, and 9 of
appendix F of this part in establishing
controls on the discharge t)f any
pollutant set forth in Table 5 of this
part. Any procedures.applied in lieu of
'these implementation procedures shall
conform with all applicable Federal.,
State, and Tribal requirements.
(fj The Great Lakes States and Tribes
shall apply the antidegradation policy
adopted pursuant to § 132.4(a)(6) for all
applicable purposes under the Glean
Water Act, including 40 CFR 131.12, for
all pollutants. . •..'/'.,
(g) For pollutants listed in Table 5 of
this part, or for any pollutant other than
those in Table 5 of this part for which
the State or Tribe demonstrates that one
or more methodologies or procedures in
this part are not scientifically
defensible, the Great Lakes States and
Tribes shall: '
(1) Apply any methodologies and .
procedures acceptable under 40 CFR
part 131 when developing water qualify
criteria or implementing narrative
criteria; and
(2) Apply the implementation
procedures in appendix F of this part or
alternative procedures consistent with
all applicable Federal, State, and Tribal
laws.". -. • '.'••'.•• --: - •' '• -'-
(h) Nothing in this part shall prohibit
the Great Lakes States and Tribes from
adopting numeric water qualify criteria;
narrative criteria, or water qualify
values that are more stringent than
criteria or values that would be derived
from application of the methodologies
set forth in appendixes A, B, C, and D
of this part or to adopt antidegradation
policies and implementation procedures
more stringent than those set forth in
appendixes E and F of this part
§ 132.5 Procedures for adoption and EPA
review. ~.
(a) The Great Lakes States and Tribes
shall adopt and submit for EPA review
and approval the criteria,
methodologies, policies, and procedures
developed pursuant to this part no later
than eighteen months from the date of
final publication of this part
•{b) The following elements must be
included in each submission to EPA for
review:
(1) The criteria, methodologies,
policies, and procedures developed
pursuant to this part;
(2) Certification by the Attorney
General or other appropriate legal
authority pursuant to 40 CFR 123.62
and 40 CFR 131,6Ce) as appropriate; .
(3-) All other information: required for
submission of NPDES program
modifications under 40 CFR 123.62; and
(4) General information which will .'
aid EPA in determining whether the
criteria, methodologies, policies and
procedures are consistent with the
requirements of the Clean Water Act
and this part; as well as information on
general policies which may affect then*
.application and implementation.
. (c) If a Great Lakes State or Tribe fails
to submit any criteria, methodologies,
policies, and procedures pursuant to
this part to EPA for review, the
requirements of this part shall apply to
discharges within the State or Federal
Indian Reservation upon EPA's
publication Of a" final rule indicating the
effective date of the part 132
requirements hi the identified
jurisdictions,. ;' -,'
fd) If a Great Lakes State or Tribe
submits criteria, methodologies, '
policies, and procedures pursuant to
this part to EPA for review, EPA shall
issue public notice and provide a >;
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules '
minimum of 30 days for public
comment on all received State or Tribal
submissions. The public notice shall
conform with the requirements of 40
CFR 123.62. Following the public
comment period, EPA shall either:
(1) Publish notice of approval of the
submission in the Federal Register
within 60 days of such submission; or
(2) Notify the State or Tribe within 90
days of such submission that EPA has
determined that all or part of the
submission is inconsistent with the
requirements of the Clean Water Act or
this part and identify any necessary
changes to obtain EPA approval. If the
State or Tribe fails to adopt such
changes within 90 days after the
notification, EPA shall publish a notice
in the Federal Register identifying the
approved and disapproved elements of
the submission and a final rule in the
Federal Register identifying the
provisions of part 132 that shall apply
to discharges within the State or Federal
Indian Reservation.
(e) EPA's approval or disapproval of
a State or Tribal submission shall be
based on the requirements of this part
find of the Clean Water Act. EPA will
determine that the criteria,
methodologies, policies, and procedures
in a State or Tribal submission are
consistent with the requirements of this
part if:
(1) For pollutants listed in Tables 1,
2,3, and 4 of this part. The Great Lakes
State or Tribe has adopted numeric
water quality criteria equal to or more
restrictive than each of the numeric
criteria in Tables 1,2,3, and 4 of this
part, talcing into account any site-
specific criteria modifications in
accordance with procedure 1 of
appendix F of this part;
(2) For pollutants other than those
listed Sn Tables 1,2,3, and 4 of this
part. The Great Lakes State or Tribe
demonstrates that either:
(i) It has adopted numeric criteria in
its water'quality standards that were
derived, or are equal to or more
restrictive than could be derived, using
the methodologies in appendixes A, B,
C, and D of this part, and the site-
specific criteria modification procedures
of appendix F of this part; or
(ii) It has adopted a procedure by "
which water quality-based effluent
limits and total maximum daily loads
are developed using the more restrictive
of:
(A) Numeric criteria adopted by the
State into State water quality standards
prior to the date of final publication of
this part; or
(B) Water quality criteria and values
derived pursuant to § 132.4(c); and
(3) For methodologies, policies, and
procedures. The Great Lakes State or
Tribe has adopted methodologies,
policies, and procedures equal to or
more restrictive than the corresponding
methodology, policy, or procedure in
§ 132.4. The Great Lakes State or Tribe
may adopt provisions which are more
restrictive than those contained in this
part; however, a more restrictive
individual provision is not justification
for adoption of a less restrictive'
requirement for a separate element of
this part.
(f) EPA's approval of the elements of
a State's or Tribe's submission will
constitute approval under section 118 of
the Clean Water Act, approval of the
submitted water quality standards
pursuant to section 303 of the Clean
Water Act, and approval of the
submitted modifications to the State's or
Tribe's NPDES program pursuant to
section 402 of the Clean Water Act.
§ 132.6 Application of part 132
requirements In Great Lakes States and
Tribes [Reserved]
[Note: The text of this section is reserved.
Text will be added as necessary through
subsequent rulemaking in accordance with
§132.5.]
Tables to Part 132
TABLE 1.—ACUTE WATER QUALITY CRI-
TERIA PCJR PROTECTION OF AQUATIC
LIFE IN AMBIENT WATER
Chemical
Arsenic (III)
Cadmium .;...
Chromium (III)
Chromium (VI)
CoDoer
Dieldrin
Endrin
Lindane
Mercury (II) .'.
Nickel
Pentachlorophenol
Phenol
Total Selenium
Zinc
CMC (ng/L)
340
12.1
1 1000
16
17.3
22
0.24
0.09
0.95
0.83
1260
.065
2 5.3
3700
20
'67
1 The toxicity of this chemical is hardness
related; the criterion expressed is at a
hardness of 50 mg/L.
2 The criterion for this chemical is pH
dependent; the criterion expressed is at a pH
of 6.5.
TABLE 2.—CHRONIC WATER QUALITY CRI-
TERIA FOR PROTECTION OF AQUATIC
LIFE IN AMBIENT WATER
Chemical
Arsenic (III)
Chromium (III)
Chromium (VI)
Dieldrin ....."...
Endrin
Mercury (II)
Nickel
Parathion
Pentachlorophenol
Phenol
Total Selenium
Zinc
CCC(ng/L)
150
'0.78
M9
11
15.2
5.2
0.056
0.037
0.44
129
0.013
2 3.3
120
5.0
160
1The toxicity of this chemical is hardness
related; the criterion expressed is at a
hardness of 50 mg/L.
2 The toxicity of this chemical is pH related;
the criterion expressed is at a pH of 6.5.
, ,,. .
TABLE 3.—WATER QUALITY CRITERIA FOR PROTECTION OF HUMAN HEALTH
Chemical
. • • '. • in ", in - . ' , '*•'.; i- -.-••'. ;vi»
&0nz@fK) ...
Chlordano .
Chlfwihflfiyflfwi
DDT . . .
DjoWrin . " .". „..»..!!..
2 4- Di mo thy! phono!
2 4-Diotoophonol .... . '. .
HoptacMor ,
HNV(ng/L)
Drinking
2.E4
9
5.E5
8.E5
1.0
7
3.E5
7.E4
300
Nondrinking
2.E5
9
1.8E6
6.E7
1.0
7
5.E5
1.7E6
300
HCV(ng/L)
Drinking
1.E4
0.2
0.07
0.1
0.5
Nondrinking
1.E5
r. 0.2
0.07
0.1
0.5 ,
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,, , . . ,.t., . .
, TABLE a.^VVATER QUAUTY CRITERIA FOR PROTECTION OF HUMAN HEALTH— Continued
••• . ' -! • ' Chemical
Hexachlorobenzene ,
Hexachloroethane ,
Lindane ,-. '
Mercury1 ..:
Methylene chloride ..,...., '..- .
PCBs (class) ..........:„ .:......
Pentachlorophenol .
2,3,7,8-TCDD .. „....
Toluene ,...".
Toxaphene ,
Trichlordethylene ...;.....'..............; ;„ ...;
HNV(ng/L)
Drinking •
10 '->
2.E3
,700
-. • . ' 2
2.E6
2.E5
1.E-4
6.E6
6
6.E5
Nondrinking
10
3.E3
800
- »•'£''
9.6E7
2.E5
1B-4
. 2.6E7
6
5.E6
HCV(ngA.)
Drinking
0.1
3.E3 .
5.E4
3.E-3 '
500
1.E-5
0.02
3.E4
Nondrinking
0.1
4.E3
2.E6
3.E-3
' • - 600 >
1.E-5
0.02
2.E5
-1 Includes MetHylmercury.
TABLE 4.—WATER QUALITY CRITERIA FOR
. ,. PROTECTION OF WILDLIFE
Chemical - . .
DDT and Metabolites
Mercury (including
Methylmercury) ...„..:.
Polychlorinated biphenyls
(PCBs)
2,3,7,6-TCDD
Criteria (pg/L)
0.87
180
17
• 0.0096
Table 5. Excluded pollutants
Alkalinity . •„ ;
Ammonia ' •.•.-".
Bacteria ;,.
. Biochemical oxygen demand (BOD)
Chlorine
Color ; \ .'.;- .;.
Dissolved oscygen: ;
Dissolved solids .
Hydrogen sulfide ,
PH .-. ., - -..;
Phosphorus .
Salinity.
"Sulfide ' : .. '
Temperature
Total and suspended solids
Turbidity
Table 6. Pollutants of Initial Focus in
the Great Lakes Water Quality
Initiative • , •
A. Pollutants that are biqaccumulative
chemicals of concern (BCCsJ:
Aldrin
4-Bromophenyl phenyl ether
Chlordane
4,4-DDD; p.p-DDD; 4,4-TDE; p.p-TDE
^^-DDE; p,p-DDE .
4,4-DDT; p,p-DDT
Dieldrin
Endrin • ;
Hepjachlor ,; ,;
Heptachlor eppxide ,
Hexachlorohenzene . ..-.;,. ,.
Hexachlorobutadiene; hexachiorc--l,3-
butadiene : .'',..
Hexachlorocyclohexane; BHC
alpha-Hexacmordcyclohexane; alpha-:
BHC ' , . -;'-. ^ ' - •.•:
beta-Hexachlorocyclohexane; beta-BHC
delta-Hexachlproeyclohexane; delta- •
BHC '
. Lindane; gamma-BHC; gamma-
• hexachlorocyclohexane
Mercury
Methoxychlor -\,'
Mirex; dechlorane
Octachlorostyrene
PCBs; polychlorinated biphenyls
Pentachlorobenzene •
Photomirex
2,3,7,^TCDD; dioxin"'
1,2,3,4-Tetrachlorpbenzene . "
1,2,4,5-Tetrachlorobenzene
Toxaphene - , :
B. Pollutants that are potential
bioaccumulative chemicals of concern:
Benzo[a]pyrene; 3,4-benzopyrene
3,4-Benzoitluoranthene;
• benzo[b]fluoranthene '.
11,12-BenzofluoranJhene;
benzo [k] fluoranthene
l,12-Benzoperylene;benzo[ghi]perylene
4-Chlorophenyl phenyl ether
l,2:5,6-Dibenzanthracene; '
dib8nz[a,h]anthracene
Dibutyl phthalate; di-n-butyl phthalate
mdeno[l,2,3-cd]pyrene; 2,3-o-
phenylene pyrene
Phenol -.-•'•
Toluene; methylbenzene
C. Pollutants that are neither
bioaccumulative chemicals of concern
nor potential bioaccumulative ;
chemicals of concern:
Acenaphthene. ' •
Acenaphthylene- -
Acrolein; 2-propenal .
Acrylonitnle
Aluminum
Anthracene .'' t- , :
Antimony . . " •
Arsenic ' ' : ' . . ' ••'.
Asbestos ; ; v
l^-Benzanthracenejbenztalanthracene
Benzene ; ^
Benzidine
Beryllium " -.. "
Bis{2-chloroeth6xy)methane
Bis(2-chloroethyl) ether
Bis(2-chloroisopropyl) ether '. . •
Bromdform; tribromomethane
Butyl benzyl phthalate
Cadmium
Carbon tetrachloride;
tetrachloromethane ,
Chlorobenzene
p-Chloro-m-cresol; 4-chloro-3-
methylphenol ..-'••
Chlorodibromomethane
Qiloroethane .
2-Chloroethyl vuiyl ether
Chloroform; trichlorbmethane
2-Chloronaphthalene
• 2-Chlorophenol •
Chlorpyrifos t ~-
Chromium .-;
Chrysene . ,
Copper " "
Cyanide ••;.'.
2,4-D; 2,4-Dichlorophenoxyacetic acid
DEHP; di(2-ethylhexyl) phthalate
Diazinon
1,2-Dichlorpbenzene
1,3-^Dichlorobenzene
1,4-Dichlorpbenzene
3,3-Dichlorobenziduie
Dichlorobromomethane;
bromodichloromethane
1,1-Dichloroethane
1,2-Dichloroethane; vinylidene chloride
1,1-Dichloroethylene
1,2-trans-Dichloroethylene
2,4-Dichlorophenol ..'-.".
1,2-Dichloropropane "
1,3-Dichloropropene; 1,3-
dichloropropylene
Diethyl phthalate
2,4-Dimethylphenol; 2,4-xylehol
Dimethyl phuialate
4;6-Dinitro-o-cresol; 2-methyl-4,6>-
- dinitrophenol
2,4-Dinitrophenol .. v.
2,4-Dinitrotoluene . ; . ''
2,6-Dmitrotoluene . .
\Dioctyl phthalate; di-n-octyl phthalate
1,2-Diphenylhydrazine
Ehdosulfan; thiddan • 1; ;
alpha-Endosulfan v"
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21016 Federal Register / Vol. 58, No. 72 /Friday, April 16, 1993 / Proposed Rules
beta-Endosulfan
Endosulfan sulfate
Endrin aldehyde
Ethylbenzane
Fluoranthona
Fluorene; 9H-fluore,ne
Fluorido
Gulbion
Hoxachlorocyclopentadiene
Hexachlorcethane
Iron
Isophorono
Lead
Malathion
Methyl bromide; bromomethane
Mathyl chloride; chloromethane
Methylene chloride; dichloromethane
Naphthalene
Nickel
Nitrobenzene
2-Nitrophenol
4-Nitroph0nol
N-Nitrosodimethylamine
N-NitrosodJphenylamine
N-Nitrosodipropylamine; N-nitrosodi-n-
propylamine
ParatMon
Pontachlorophenol
Fhenanthrene
Pyrena
Selenium
Silver "" ; ';
1,1,2,2-Tetradilorciethane
Tetrachloroethylene
Thallium
1,2,4-Trichlorobenzene '
1,1,1-Trichloroethane
1,1,2-Trichloroethana
Trichloroethylene; trichloroethene
2,4,6-Trichlorophenol
Vinyl chloride; chloroethylene;
chloroethene
Zinc
Appendix A to Part 132—Great Lakes
Water Quality Initiative Methodologies
for Development of Aquatic Life
Criteria and Values
Methodology for Deriving Aquatic Life
Criteria'. Tier I
I. Definitions
A. Material of Concern, 1. Each saparate
chemical that does not ionize substantially in
mo»t natural bodies of water should usually
bo considered a separata material, except
possibly for structurally similar organic
compounds that only exist in large quantities
as commercial mixtures of the various
compounds and apparently have similar
biological, chemical, physical, and
toxicologies! properties.
2. For chemicals that ionize substantially
in most natural bodies of water (e.g. some
phenols and organic acids, soma salts of
phenols and organic acids, and most
inorganic salts and coordination complexes
of metals and metalloids), all forms that
would be in chemical equilibrium should
usually be considered one material. Each
different oxidation state of a metal and each
different non-ionizable cpvalently bonded
organometallic compound should usually be
" considered a separate material.
3. The definition of the material should
include an operational analytical component
Identification of a material simply as
"sodium," for example, implies "total
sodium", but leaves room for doubt. If "total"
is meant, it must be explicitly stated. Even
"total" has different operational definitions,
some of which do not necessarily measure
"all that is there" in all samples. Thus, it is
also necessary to reference or describe the
analytical method that is intended. The
selection of the operational analytical
component should take into account the
analytical and environmental chemistry of
the material, the desirability of using the
same analytical method on samples from
laboratory tests, ambient water, and aqueous
effluents, and various practical
considerations, such as labor and equipment
requirements, and whether the method
'would require measurement in the field or
would allow measurement after samples are
transported to a laboratory.
The primary requirements of the
operational analytical component are that it
be appropriate for use on samples of
receiving water, that it be compatible with
the available toxicity and bioaccumulation
data without making extrapolations that are
too hypothetical, and that it rarely result in
underprotection or overprotection of aquatic
organisms and their" uses.
Because an ideal analytical measurement
will rarely be available, a compromise
measurement will usually have to be used.
This compromise measurement must fit with *
the general approach that if an ambient
concentration is lower than the criterion,
unacceptable effects will probably not occur,
i.e., the compromise measure must not err on
the side of underprotection when
measurements are made on a surface water.
Because the chemical and physical properties
of an effluent are usually quite different from
those of the receiving water, an analytical
method that is acceptable for analyzing an
effluent might not be appropriate for
analyzing a receiving water, and vice versa.
If the ambient concentration calculated from
a measured concentration in an effluent is
higher then the criterion, an additional
option is to measure the concentration after
dilution of the effluent with the receiving
water to determine if the measured
concentration is lowered by such phenomena
as complexation or sorption. A further
option, of course, is to derive a site-specific
criterion. Thus, the criterion should be based
on an appropriate analytical measurement,
but the criterion is not rendered useless if an
ideal measurement either is not available or
is not feasible.
Note: The analytical chemistry of the
material might have to be taken into account
when defining the material or when judging
the acceptability of some toxicity tests, but a
criterion must not be based on the sensitivity
of an analytical method. When aquatic
organisms are more sensitive than routine
. analytical methods, the proper solution is to
develop better analytical methods, not to
underprotect aquatic life.
B. Acute Toxicity. An adverse effect
(usually lethality) in an aquatic organism as
a result of exposure to a toxicant for a
relatively short period (i.e., 24 to 96 hours)
of tune relative to the organism's natural life
span.
C. Chronic Toxicity. An adverse effect (i.e.,
reduced growth, reproductive effects, etc.> in
addition to lethality) in an aquatic organism
as a result of exposure to a toxicant for a
significant portion of time relative to the
organism's natural life span.
D. Collection of Data
A. Collect all data available on the material
concerning toxicity to aquatic animals and •,
plants.
B. AH data that are used should be
available in typed, dated, and signed hard
copy (publication, manuscript, letter,
memorandum, etc.) with enough supporting
information to indicate that acceptable test
procedures were used and that the results are
probably reliable. In some cases, it may be
appropriate to obtain written information
from the investigator, if possible. Information
that is not available for distribution shall not
be used.
C. Questionable data, whether published or
unpublished, must not be used. For example,
data must be rejected if they are from tests
that did not contain a control treatment, tests
in which too many organisms in the control
treatment died or showed signs of stress or
disease, and tests in which distilled or
deionized water was used as the dilution
water without the addition of appropriate
salts. '
D. Data on technical grade, materials may
be used if appropriate, but data on
formulated mixtures and emulsifiable
concentrates of the material must not be
used.
E. For some highly volatile, hydrolyzable, •
or degradable materials, it is probably
appropriate to use only results of flow-
through tests in which the concentrations of
test material in test solutions were measured
using acceptable analytical methods.
F. Data must be rejected if obtained using:
1. Brine shrimp, because they usually only
occur naturally in water witn salinity greater
than35g/kg.
2. Species that do not have reproducing .
wild populations in North America.
3. Organisms that were previously exposed
to substantial concentrations of the test
material or other contaminants.
4. Saltwater species except for use in
deriving acute-chronic ratios.
G. Questionable data, data on formulated
mixtures and emulsifiable concentrates, and
data obtained with non-resident species or
previously exposed organisms may be used
to provide auxiliary information but shall not
be used in the derivation of criteria.
III. Required Data
. A. Certain data should be available to help
ensure that each of the major kinds of
possible adverse effects receives adequate
consideration. Results of acute and chronic
toxicity tests with representative species of
aquatic animals are necessary so that data
available for tested species can be considered
a useful indication of the sensitivities of
appropriate untested species. Fewer data
concerning toxicity to aquatic plants are
required because procedures for conducting
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Federal Register / Vol. 58, No. 72 / Friday. April 16, 1993 / Proposed Rules
21017
tests with plants and interpreting the results
of such tests are not as well developed,
B. To derive a Great Lakes Tier I criterion
for freshwater aquatic organisms and their
uses, the following must be available:;
1, Results of acceptable acute tests (see
section IV of this appendix) with at least one
species of freshwater animal in at least eight
different families such that all of the .
following are included: ,
a. The family Salmonidae in the class
Osteichthyes;
' - • b. One ojther family (preferably a
commercially, orrecreationally important,
warm-water species) in the class Osteichthyes
, (e.g., bluegill, channel catfish, etc.);
c.,A third family in the phylum Chordata
(e.g., fish, amphibian, etc.); __
d. A planktonic crustacean (e.g., a
cladoceran, copepod, etc.);
e. A benthic crustacean (e.g., ostracod,
isopod, amphipod, crayfish, etc.);
f. An insect (e.g., mayfly, dragonfly,
damselfly, stonefly, caddisfly, mosquito,
midge, etc.); _ • -
g. A family in a phylum other than
Arthropoda or Chordata (e.g., Rotifera,
Annelida, Mollusqa, etc.); -
h. A family in any order of insect or any
phylum not already represented.
2. Acute-chronic ratios (see section VI of
this appendix) with a species of aquatic'
animal in at least three different families
.provided that of the three species:
a. At least one is a fish;
b. At least one is an invertebrate; and
, c. At least one species is an acutely
sensitive freshwater species (the other two
may be saltwater species).
3. Results of at least one acceptable test
with a freshwater algae or vascular plant is
-desirable but not required for criterion.
derivation (see section VIE of this appendix).
If plants are among the aquatic organisms
_most sensitive to the material, results of a test
With a plant in another phylum (division) •
should also be available. - " - •
C. If all required data are available, a
numerical criterion can usually be derived, _
except in some cases. Also, if a criterion is
to be related to a water quality characteristic
(see sections V and VII of this appendix)
more data will be required.
Similarly, if all required data are not
available, a numeric criterion should not be "
derived except in special cases. For example,
derivation of a criterion might not be possible
if the available acute-chronic ratios vary by
more than a factor of ten with no apparent
pattern. Also, if a criterion is to be related to
a water quality characteristic (see sections V
and VII of this appendix) more data will be
required. .
Similarly, if all required data are not
available, a numeric criterion should not be
derived except in special cases.,
D. Confidence in a criterion usually
increases as the amount of available pertinent
information increases. Thus, additional data
are usually desirable.
IV. Final Acute Value
. A. Appropriate measures of the acute
(short-term) toxicity :of the material to a
variety of species of aquatic animals are used
to calculate the Final Acute Value. The Final
Acute Value is an estimate of the
concentration of the material corresponding
to a cumulative probability of 0.05 in tha
acute tbxicity values for the genera with
which acceptable acute tests have been
conducted on the material. However, in some
cases, if the Species Mean Acute. Value of a
commercially or recreationally important
species of the Great Lakes System is lower
than that calculated Final Acute Value, then
the Species Mean Acute Value replaces the
calculated Final Acute Value in order to
provide protection for that important species,
B. Acute toxicity tests shall be conducted
using acceptable procedures.
C. Except for results with saltwater '.
annelids and mysids, results of acute tests
during which the test organisms were fed
shall not be used, unless data indicate that
the food did not affect the toxicity of the test
material.
• D. Results of acute tests conducted hi •.
unusual dilution water, e.g., dilution water hi
which total organic carbon or particulate
matter exceeded five mg/L, should not be
used, unless a relationship is developed
between acute toxicity and organic carbon or
particulate matter, or unless data show that
organic carbon or particulate matter, etc., do
not affect toxicity. .
E. Acute values must be based upon
endpoints which reflect the total severe
adverse impact of the test material on tha
organisms used hi the test. Therefore, only
the following kinds of data on acute tpxicity '
to aquatic animals shall be used:
1. Tests with daphnids and'other
cladocerans must be started with organisms
less than 24 hours old and tests with midges
should be started with second or third instar
larvae. The results should be the 48-hour
EC50 based on percentage of organisms lulled •
or immobilized, if such an EC50 is not
available for'a test, the 48-hour LC50 should
be used in place of the desired 48-hour ECSO.
An ECSO or LC50 of longer than 48 hours can
be used as long as the animals were not fed
and the control animals were acceptable at
the end of the test
2. The results of srtest with embryos and
larvae of barnacles, bivalve molluscs (clams,
mussels, oysters and scallops), sea urchins,
lobsters, drabs, shrimp and abalones should
be the 96-hour ECSO based on percentage of
organisms with incompletely developed
shells plus percentage of organisms killed. If"
such an ECSO is not available from a test, of
the values that are available from the test, the
lowest of the following should be used in
place of the desired 96-hour ECSO: 48- to 96-
hour ECS Os based on percentage of organisms
with incompletely developed shells plus
percentage of organisms killed, 48-to 96-
hour ECS Os based upon percentage of
organisms with incompletely developed
shells, and 48- to 96-hour LCSOs.
3. The result of tests with all other aquatic
animal species and older life stages of
barnacles, bivalve molluscs (clams, mussels,
oysters and scallops), sea urchins, lobsters, ~
crabs, shrimp and abalones should be the 96-
hour EC50 based on percentage of organisms
exhibiting loss of equilibrium plus
percentage of organisms immobilized plus
percentage of organisms killed. If such an
ECSO is not available from a test, of the
values that are available from a test the lower
of the following should be used in place of
the desired 96-hour ECSO: the 96-hour ECSO
based on percentage of organisms exhibiting
loss of equilibrium plus percentage of •
organisms immobilized and the 96-hour
LC50.
4. Tests whose results take into account the
number of young produced, such as most
tests with protozoans, are not considered
acute tests, even if the duration was 96 hours
or less.
5. If the tests were conducted properly,
acute values reported as "greater than"
values and those which are above the
solubility bf the test material should be used,
because rejection of such acute values would
bias the Final Acute Value by eliminating '
acute values for resistant species.
F. If the acute toxicity of the material to
aquatic animals has been shown to be related
to a water quality characteristic such as
hardness or particulate matter for freshwater
animals, refer to section V of this appendix.
. G. The agreement of the data within and
between species must be considered. Acute
values that appear to be questionable in .
comparison with other acute and chronic
data for the same species and for other
species in the same genus must not be used.
For example, if the acute values available for
a species or genus differ by more than a
fector of 10, rejection of some or all of the
values is probably appropriate.
. • H. If the available data indicate that one or
more life stages are at least a fector of two
or more resistant than one or more other life
stages of the same species, the data for the
more resistant life stages must not be used in
the calculation of the Species Mean Acute '
Value because a species cannot be considered
protected from acute toxicity if all of the life
stages are not protected, ..• ;
I. For each species for which at least one
acute value is available, the Species Mean
Acute Value (SMAV) should be calculated as
the geometric mean of the results of all flow-
through tests in which the concentrations of
test material were measured. For a species for
.which no such result is available, the SMAV
shall be calculated as the geometric of all
available acute values, i.e., results of flow-
through tests in which the concentrations
were not measured and results of static and
renewal tests based on initial concentrations
(nominal concentrations are acceptable for
most test materials if measured
concentrations are not available) of test
material.
Note 1: Data reported by original
investigators must not be rounded off.
Results bf all intermediate calculations must
be rounded off to no fewer than four
significant digits.
Note 2: The geometric mean of N numbers
is the Nth root of the product of the N
numbers. Alternatively, the geometric mean
can be calculated by adding the logarithms of
the N numbers, dividing the sum by N, and
taking the antilog of the quotient. The
geometric mean of two numbers is the square
root of the product of the two numbers, and
the geometric mean of one number is that
number. Either natural (base e) or common
(base 10) logarithms can be used to calculate
geometric means as long as they are used
consistently within each set of data, i.e., the
antilog used must match the logarithms used.
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Federal Register / Vol. 58, No. 72 / Friday, April 16, J993 / Proposed Rules
Note 3: Geometric means, rather than
arithmetic means are used here because the
distributions of sensitivities of individual
organisms in toxidty tests on most materials
and the distributions of sensitivities of
species within a genus are more likely to be
lognormal than normal. Similarly, geometric
moans are used for acute-chronic ratios
because quotients are likely to be closer to
lognormal than normal distributions. In
addition, division of the geometric mean of
a set of numerators by the geometric mean of
the set of denominators will result in the
geometric mean of the set of corresponding
quotients.
J. tor each genus for which one or more
SMAVs are available, the Genus Mean Acute
Value (GMAV) shall be calculated as the
geometric mean of the SMAVs available for
the genus.
K. Order the GMAVs from high to low.
L. Assign ranks, R, to the GMAVs from "1"
for the lowest to "N" for the highest. If two -
or more GMAVs are identical, assign them
successive ranks.
M. Calculate the cumulative probability, P,
for each GMAV as R/(N+1).
N. Select the four GMAVs which have
cumulative probabilities closest to 0.05 (if
there are less than 59 GMAVs, these will
always be the four lowest GMAVs).
O. Using the selected GMAVs andPs,
calculate.
S2 =
^GMAV^-G^f1^
Note; Natural logarithms (logarithms to
btsa e, denoted as In) are used herein merely
because they are easier to use on some hand
calculators and computers than common
(bra 10) logarithms. Consistent use of either
will produce the same result
P. If for • commercially or recreationally
important species of the Groat Lakes System
. tht goomatric mean of the acute values from
flow-through tests hi which the
concentrations of test material were
metjured is lower than the calculated Final
Acute Value (FAV), then that geometric mean
must bo used as the FAV instead of the
calculated FAV.
Q, S«a section VI of this appendix. •
V, Final Acute Equation
A, When enough data are available to show
that scute toxidty to two or more species is
similarly related to a water quality
characteristic, the relationship shall be taken
Into account as described in sections V.B
through G of this appendix or using analysis
ofcovmriance. The two methods are
equivalent and produce identical results. The
manual method described below provides an
understanding of this application of
covariance analysis, but computerized
versions of covariance analysis are much
more convenient for analyzing large data sets.
If two or more factors affect toxicity, multiple
regression analysis shall be used.
B. For each species for which comparable
acute toxicity values are available at two or
more different values of the water quality
characteristic, perform a least squares
regression of the acute toxicity values on the
corresponding values of the water quality
characteristic to obtain the slope and its 95
percent confidence limits for each species.
Note: Because the best documented
relationship is that between hardness and
_5> GMAV)-s(]T(Vp))
acute toxicity of metals hi fresh water and a
log-log relationship fits these data, geometric
means and natural logarithms of both toxicity
and water quality are used in the rest of this
section. For relationships based on other
water quality characteristics, such as pH,
temperature, or salinity, no transformation or
a different transformation might fit the data
better, and appropriate changes will be
necessary throughout this section.
"C. Decide whether the data for each species
is useful, taking into account the range and
number of the tested values of the water
quality characteristic and the degree of
agreement within and between species. For
example, a slope based on six data points
might be of limited value if it is based only
on data for a very narrow range of values of
the water quality characteristic. A slope
based on only two data points, however, '
might be useful if it is consistent with other
information and if the two points cover a
broad enough range of the water quality ,
characteristic. In addition, acute values that
appear to be questionable in comparison with
other acute and chronic data available for the
same species and for other species in the
same genus shall not be used. For example,
if after adjustment for the water quality
characteristic, the acute values available for
a species or genus differ by more than a
factor of 10, rejection of some or all of the
values is probably appropriate. If useful
slopes are not available for at least one fish
and one invertebrate or if the available slopes
are too dissimilar or if too few data are
available to adequately define the
relationship between acute toxicity and the
water quality characteristic, return to section
IV.G of this appendix, using the results of
tests conducted under conditions and in
waters similar to those commonly used for
toxicity tests with the species.
D. Individually for each species calculate
the geometric mean of the available acute
values and then divide each of the acute
values for a species by the me.an for the
species. This normalizes the acute values so
that the geometric mean of the normalized •
values for each species individually and for
any combination of species is 1.0.
E. Similarly normalize the values of the .
water quality characteristic for each species
individually.
F. Individually for each species perform a
least squares regression of the normalized
acute values of the water quality
characteristic. The resulting slopes and 95
percent confidence limits will be identical to
those obtained in section B of this appendix.
Now, however, if the data are actually...
plotted, the line of best fit for each individual
species will go through the point 1,1 in the
center of the graph.
G. Treat all of the "normalized data as if
they were all for the same species and
perform a least squares regression of all of the
normalized acute, values on the
corresponding normalized values of the
water quality characteristic to obtain the
pooled acute slope, V, and its 95 percent
confidence limits. If ail of the normalized
data are actually plotted, the line of best fit
will go through the point 1,1 in the center of
the graph.
. H. For each species calculate the geometric
mean, W, of the acute toxicity values and the
geometric mean, X, of the values of the water
quality characteristic. (These were calculated
hi sections D and E of this appendix".)
I. For each species, calculate the logarithm,
Y, of the Species Mean Acute Value (SMAV)
at a selected value, Z, of the water quality
characteristic using the equation:
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Federal Register / Vol. 58, No. 72 7 Friday, April 16, 1993 / Proposed Rules
21019
Y = In W - V(ln X - In Z)
J. For each species calculate the SMAV at;
X using the equation: "
*'-.•.;•::;.'SMAV =eY.-,:.;;.
Note: Alternatively, the SMAVs at Z can be
obtained by skipping step H above, using the
equations in steps I and J to adjust each acute
value individually to Z, and then calculating
.the geometric mean of the adjusted values for
eac'h species individually. This alternative
procedure allows an examination of the range
of the adjusted acute values for each species.
K. Obtain the Final Acute Value at Z by
using the procedure described in sections
IV. J through 'O of this appendix,
L. If for a commercially of recreationally
important species of the Great Lakes System
the. geometric mean of the acute values at Z
from flow through tests in which the
concentrations of the test material were
measured is lower than the Final Acule
Value at Z, then the geometric mean must be
usejd as the Final Acute Value instead of the
Final Acute Value, , '
M. The Final Acute Equation is written as:
Final Acute Value = e(vPn(water(Juality <*aracfcristic)]+A-V[ln Z])
where:' .
V=pooled acute slope, and A=ln(Final
Acute Value at Z).
Because V, A, and'Z are known, the Final
Acute Value can be calculated for any '
selected value of the water quality
characteristic.
VL Final Chronic Value
A.iDepending on the data that are available
concerning-chronic toxicity to aquatic
animals, the Final (Chronic Value might be
'calculated in the same manner as the'Final
Acute Value or by dividing the Final Acute
Value by the Final Acute-Chronic Ratio. In
some cases, it may not be possible to
calculate a Final Chronic Value for Tier I.
Note: As the'name implies, the acute-
chronic ratio (ACR) is a way of relating acute
and chronic toxicities. The acute-chronic
ratio is basically the inverse of the
application factor, but this new name-is
better because it is more descriptive and
should help prevent confusion between
"application factors" and "safety factors."
Acute-chronic ratios and application factors
are ways of relating the acute and chronic
toxicities of a material to aquatic organisms.
Safety factors are used to provide an extra
margin of safety beyond the known or
estimated sensitivities of aquatic organisms.
Another advantage of the acute-chronic ratio
is that it will usually be greater than one; this
should avoid the Confusion as to whether a
large application factor is one that is close to -
unity or one that has a denominator that is
much greater than the numerator.
B. Chronic values shall be based on results
of flow-through (except renewal is acceptable
for daphnids) chronic tests in which the
concentration of test material in the test
solutions were properly measured at
appropriate tunes during the test.
- C. Results of chronic tests in which
survival, growth, or reproduction in the
, control treatment was unacceptably low shall
not be used. The limits of acceptability will
depend on the species.
D. Results of chronic tests conducted in
unusual dilution water, e.g., dilution water in
which total organic carbon or particulate •
matter exceeded five mg/L, shall not be used,
unless a relationship is developed between
chronic toxicity and organic carbon or
particulate matter, or unless data show that
organic carbon, particulate matter, etc., do
not affect toxicity.
E. Chronic values must be based on
eridpoints and lengths of exposure
appropriate to the species. Therefore, only
results of the following kinds of chronic
toxicity tests shall be used:
1. Life-cycle toxicity tests consisting of ;
exposures of each of two or more groups of.,..'
individuals of a species to a different
concentration of the test material throughout
a life cycle. To ensure that all life stages and
: life processes are exposed, tests with fish
should begin with embryos or newly hatched
young less than, 48 hours old, continue
through maturation and reproduction, and
should end not less than 24 days (90 days for
sahnonids) after the hatching of the next
generation. Tests with daphnids should begin
with young less than 24 hours old and last
for not less than 21 days, and for
Ceriodaphnia not less than seven days. Tests
with mysids should begin With young less.
than 24 hours old and continue until seven
days past the median time of first brood
release.in the controls. For fish, data should
be obtained and analyzed on survival and
growth of adults and young, maturation of
males and females, eggs spawned per female,
embryo viability (salmonids only), and
hatchability. For daphnids, data should be
obtained and analyzed on survival and young
per female. For toysids, data should be
obtained and analyzed on survival, growth,
and young per female;
•2. Partial life-cycle toxicity tests consist of
exposures of each of two more groups of
individuals of a species of fish to a different
concentration of the test material through
most portions of a life cycle. Partial life-cycle
tests are allowed with fish species that
require more than a year to reach sexual
maturity, so that all major life stages can be
exposed to the test material in less than 15
months. Exposure to the test material should
begin with Immature juveniles at least two
months prior to active gonad development,
continue through maturation and
reproduction, and end not less than 24 days
(90 days for sahnonids} after the hatching of
the next generation. Data should be obtained
and analyzed on survival and growth of -
adults and young, maturation of males and
females, eggs spawned per female, embryo
viability (sahnonids only), and hatchability.
• 3. Early life-stage toxicity tests consisting -
of 28-to 3 2-day (60 days post hatch for
sahnonids) exposures of the early life stages
of a species of fish from shortly after
fertilization through embryonic, larval, and
early juvenile development. Data should be
obtained and analyzed on survival and
growth. •
Note: Results of an. early life-stage.test are
used as predictions of results of life-cycle
and partial life-cycle tests with the same
species. Therefore, when results of a life-
cycle or partial life-cycle test are available,
results of an early life-stage test with the
same species should not be used. Also,
results of early life^stage tests in which the
incidence of mortalities or abnormalities
increased substantially near the end of the
test shall not Be used because the results of
such tests are possibly not good predictions
of comparable life-cycle or partial life-cycle
tests. • •
F. A chronic value may be obtained by
calculating the geometric mean of the lower
and upper chronic limits from a chronic test
or by analyzing chronic data using regression
analysis.
1. A lower chronic limit is the highest
tested concentration:
a. In an. acceptable chronic test; .
b. Which did not cause an unacceptable
amount of adverse effect on any of the
specified biological measurements; and
c. Below which no tested concentration
caused an unacceptable effect,
.2. An upper chronic limit is the lowest
tested concentration:
a. In an acceptable chronic test;
b. Which did not cause an unacceptable
amount of adverse effect on one or more of
the specified biological measurements; and
, c. Above which all tested concentrations
also caused such an effect. ' •'.
Note: Because various authors have used a
variety of terms and definitions to interpret '
and report results of chronic tests, reported
results should be reviewed carefully. The
amount of effect that is considered
unacceptable is often based on a statistical
hypothesis test, but might also be defined in
terms of a specified percent reduction from
, the controls. A small percent reduction (e^g.,
three percent) might be considered
acceptable even if it is statistically "
significantly different from the control,
whereas a- large percent reduction (e.g., 30 .
percent) might be considered unacceptable
even if it is not statistically significant. •
G. If the chronic toxicity of the material to
aquatic animals has been shown to be related
to a water quality characteristic such as
hardness or particulate matter for freshwater
annuals, refer to section VII of this appendix.
H. If chronic values are available for
species in eight families as described in ,
section ffl.B.l of this appendix, a Species
Mean Chronic Value (SMCV) shall be
calculated for each species for which at least
one chronic value is available by calculating
the geometric mean of all chronic values
available for the species, and appropriate
Genus Mean Chronic Values' shall also be
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
calculated, "The Final Chronic Value shall be
obtained using the procedure described in
sections IVJ through O of this appendix. See
section VI.M of this appendix.
I. For each chronic value for which at least
ona corresponding appropriate acute value is
available, calculate an acute-chronic ratio,
using for the numerator the geometric mean
of the results of all acceptable flow-through
(except static is acceptable for daphnids and
midges) acute tests in the same dilution
•water in which the concentrations are
measured. For fish, the acute test(s) should
b« conducted with juveniles. The acute
tos:(s) should be part of the same study as the
chronic test. If acute tests are not conducted
as part of the same study, acute tests
conducted in the same laboratory and
dilution water, but in a different study, may
ba used. If no such acute tests are available,
results of acute tests conducted in the same
dilution water in a different laboratory may
be us«d. If no such acute tests are available,
an acute-chronic ratio shall not be calculated.
J, For each species, calculate the Species
Mean Acute-Chronic Ratio as the geometric
mean of all acute-chronic ratios available for
that species. Preference should be given to
freshwater (versus saltwater) species acute-
chronic ratios when calculating a Final
Acute-Chronic Ratio. If the minimum acute-
chronic ratio data requirements (as described
in section HI.B.2 of this appendix) are not
mot with freshwater data alone, saltwater
data may be used.
K. For some materials, the acute-chronic
ratio seems to be the same for all species, but
for other materials the ratio seems to increase
or decreaso as the Species Mean Acute Value
(SMAV) increases. Thus the Final Acute-
Chronic Ratio can bo obtained in four ways,
depending on the data available:
1. If the species mean acute-chronic ratio
seems to increase or decrease as the SMAVs
increase, the Final Acute-Chronic Ratio shall
bo calculated as the geometric mean of the
acute-chronic ratios for species whose
SMAVs aro dose to the Final Acute Value.
2. If no major trend is apparent and the
acute-chronic ratios for all species are within
• factor often, the Final Acute-Chronic Ratio
shall be calculated as the geometric mean of
all of the Species Mean Acute-Chronic Ratios
for both freshwater and saltwater species.
3. For acute tests conducted on metals and
possibly other substances with embryos and
larvae of barnacles, bivalve molluscs, sea
urchins, lobsters, crabs, shrimp, and abalones
(sea section IV.E.2 of this appendix), it is
probably appropriate to assume that the acute
to chronic ratio is two. Chronic tests are very
difficult to conduct with most such species,
but it is likely that the sensitivities of
embryos and larvae would determine the
results of life cycle tests. Thus, if the lowest
available SMAVs are determined with
embryos and larvae of such species, the Final
Chronic Value Is equal to the Criterion
Maximum Concentration (see section VI of
this appendix).
4. If the most appropriate species mean
acute-chronic ratios are less than 2.0, and
especially If they are less than 1.0,
acclimation has probably occurred during the
chronic test In this situation, because
continuous exposure and acclimation cannot
be assured to provide adequate protection in
field situations, the Final Acute-Chronic
Ratio should be assumed to be two, so that
the Final Chronic Value is equal to the
Criterion Maximum Concentration. (See
section X.B of this appendix)
If the available species mean acute-chronic
ratios do not fit one of these cases, a Final
Acute-Chronic Ratio probably cannot be
obtained and a Final Chronic Value probably
cannot be calculated for Tier I.
Preference shall be given to freshwater
(versus saltwater) species acute-chronic
ratios when calculating Final Acute-Chronic
Ratio. If the minimum acute-chronic ratio
data requirements (as described in section
ilI.B.2 of this appendix) are not met with
freshwater data alone, saltwater data may be
used. -
L. Calculate the Final Chronic Value by
dividing the Final Acute Value by the Final'
Acute-Chronic Ratio. If there is a Final Acute,
Equation rather than a Final Acute Value, see
also section V of this appendix. .
M. If the Species Mean Chronic Value of
a commercially or recreationally important
species of the Great Lakes System is lower
than the calculated Final Chronic Value, then
that Species Mean Chronic Value must be
used as the Final Chronic Value instead of
the calculated Final Chronic Value.
N. See section VHI of this appendix.
VII. Final Chronic Equation
A. A Final Chronic Equation can be
derived in two ways. The procedure
described here in section VII. A of this
appendix will result in the chronic slope
being the same as the acute slope. The
procedure described in sections VII.B
through N of this appendix will usually
result in the chronic slope being different
from the acute slope.
1. If acute-chronic ratios are available for
enough species at enough values of the water
quality characteristic to indicate that the
acute-chronic ratio is probably the same for
all species and is probably independent of
the water quality characteristic, calculate the
Final Acute-Chronic Ratio as the geometric
mean of the available Species Mean Acute-
Chronic Ratios.
2. Calculate the Final Chronic Value at the
selected value Z of the water quality
characteristic by dividing the Final Acute
Value at Z. (see section V.M of this appendix)
by the Final Acute-Chronic Ratio.
3. Use V=pooled acute slope (see section
V.M of this appendix)
as
L=pooled chronic slope.
4. See section VnM of this appendix.
B. When enough data are available to show
that chronic toxicity to at least one species
is related to a water quality characteristic, the
relationship should be taken into account as
described in sections B through G below or,
using analysis of covariance. The two
methods are equivalent and produce
identical results. The manual method
described below provides an understanding
of this application of covariance analysis, but
computerized versions of covariance analysis
ere much more convenient for analyzing
large data sets. If two or more factors affect
toxicity, multiple regression analysis shall be.
used. .
C. For each species for which comparable
chronic toxicity values are available at two or
more different values of the water quality
characteristic, perform a least squares
regression of the chronic toxioity values on
the corresponding values of the water quality
characteristic to obtain the slope and its 95
percent confidence limits for each species.
Note:,Because the best documented
relationship is that between hardness and
acute toxicity of metals in fresh water and a
log-log relationship fits these data, geometric
means and natural logarithms of both toxicity
and water quality are used in the rest of this
section. For relationships based on other
water quality characteristics, such as pH,
temperature, or salinity, no transformation or
a different transformation might fit the data
better, and appropriate changes will be
necessary throughout this section. It is
probably preferable, but not necessary, to use
the same transformation that was used with
the acute values in section V of this
appendix.
•D. Decide whether the data for each species
is useful, taking into account the range and
number of the tested values of the water
quality characteristic and the degree of
agreement within and between species. For
example, a slope based on six data points
might be of limited value, if it is based only
on data for a very narrow range of values of
the water quality characteristic. A slope
based on only two data points, however,
might be more useful if it is consistent with
other information and if the two points cover
a broad range of the water quality
characteristic. In addition, chronic values
that appear to be questionable in comparison
with other acute and chronic data available
for the same species and for other species in
• the same genus "probably should not be used.
For example, if after adjustment for the water
quality characteristic, pthe chronic values
available for a species or genus differ by more
than a factor of 10, rejection of some or all
of the values is probably appropriate. If a
useful chronic slope is not available for at
Jeast one species or if the available slopes are
too dissimilar or if too few data are available
to adequately define the relationship between
chronic toxicity and the water quality
characteristic, it might be appropriate to
assume that the chronic slope is the same as
the acute slope, which is equivalent to •
assuming that the acute-chronic ratio is
independent of the water quality
characteristic. Alternatively, return to section
VI.H of this appendix, using the results of
tests conducted under conditions and in
waters similar to those commonly used for
toxicity tests with the species.
E. Individually for each species calculate
the geometric mean of the available chronic
values and then divide each chronic value for
a species by the mean for the species. This
normalizes the chronic values so that the
geometric mean of the normalized values for
each species individually, and for any
combination of species, is 1.0.
F. Similarly, normalize the values of the
water quality characteristic for each species
individually. " ,.
G. Individually for each Species perform a
least squares regression of the normalized
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
21021
chronic toxicity values on the corresponding
normalized values of the water quality
characteristic. The resulting slopes and the
95 percent confidence limits will be identical
to those obtained in section VTLB of this '
appendix Now, however, if the data are
actually plotted, the line of best fit for each
individual species will go through the point
1,1 in the center of the. graph.
•.. H, Treat all of the normalized data as if
they were all the same species and perform
a least squares regression of all of the
normalized chronic values on the ..
corresponding normalized values of the
water quality characteristic to obtain tie
pooled chronic slope, L, and its 95 percent
confidence limits. • • , - , .
If all normalized data are actually plotted,
• the line of best fit will go through the point
1,1 in the center of the graph.
I. For each species, calculate the geometric
mean. M, of the toxicity. values and the
geometric mean, P, of the values of the water
_ quality characteristic. (These are calculated
in sections Vn.E and F of this appendix.)
J. For each species, calculate the logarithm,
Q, of the Species Mean Chronic Value at a
selected value, Z, of the water quality
characteristic using the equation:
'Q = lnM-L(lnP-lnZ)
Note: Although it is not necessary, it is
recommended that the same value, of the
water quality characteristic be used -here as
was used in section VI of this appendix. -
K. For each species, calculate a Species
Mean Chronic Value at Z using the equatidn:
Note: Alternatively, the Species. Mean '•
Chronic Value at Z can be obtained by
skipping section VH.J of this appendix, using
the equations in sections Vn.J and K of this
appendix to adjust each chronic value
individually to Z and then calculating the
geometric means of the adjusted values for
each species individually. This alternative
procedure allows an examination of the range
of the adjusted chronic values for .each
species. - : '
, t. Qbtain.the Final Chronic Value at Z by
using the procedure described in sections
IV.J through Oof this appendix.'"-''.,.
M. If the Species Mean Chronic Value at
_Z of a commercially or recreationally '
important specie's of the Great Lakes System
is lower than the calculated Final Chronic :
Value at Z, then that Species Mean Chronic
Value shall be used as the Fmal Chronic
Value at Z instead of the calculated Final
Chronic Value.
• N. The Final Chronic Equation is •''-
written as:
Final Chronic Value = e(L[ln(water quality <*aracterisuc)j+ins-L[inZ])
where:
L=popled chronic slope and S=Final
: Chronic Value at Z.
; Because L, S, and Z are known, the Final
Chronic Value can be calculated for any
selected value of the water quality '-' • '
characteristic.
Vin. Final Plant Value
A, Appropriate measures.of the toxicity of
the material to aquatic plants are used to
. Compare the relative.sensitivities of aquatic
plants and animals. Although procedures for
conducting and interpreting the results of
toxicity tests with plants are not well-
developed, results of tests with plants
usually indicate that criteria which
adequately protect aquatic animals and their
uses will probably also protect aquatic plants
and their uses.
B. A plant value'is the result of a 96-hour
test .conducted with an alga or a chronic test
conducted with an aquatic vascular plant.
Note: A test of the toxicity of a metal to a '
plant shall not be used if the medium
contained an excessive amount of a •
complexing agent, such as EDTA, that might
affect the toxicity of the metal. ' '.,•'.
' Concentrations'of EDTA above 200 ug/L
should probably be considered excessive.
C. The Final Plant Value shall be obtained
by selecting the lowest result from a test with
an important aquatic plant species in which
the concentrations of test material are
measured and the endpoint is biologically
important. .-• ':
DC. Other Data ; ' •
Pertinent information that could not be
used in earlier sections might be available
concerning adverse effects on aquatic
organisms and their uses. The most
'important of these are data on cumulative ,
and,delayed toxicity, reduction in survival,
growth, or reproduction, or any other adverse
effect that has been shown to be biologically"
important. Especially important are data for.
species for which ho o.ther data are available
Data from behavioral, biochemical,
physiological, microcosm, and field studies
might also be available. Data might be
available from tests conducted in unusual
dilution water (see sections IV.D and VLD of
this appendix), from chronic tests in which
the concentrations were not measured (see
section VLB of this appendix), from tests
with previously exposed organisms (see
section H.F'of this appendix), and from tests
on formulated mixtures or emulsifiable
' concentrates (see section H.D of this
appendix). Such data might affect a criterion
if the data were obtained with an important
species, the test concentrations were
measured, and the endpoint was biologically
important.
X. Criterion
A. A criterion consists of two
concentrations: the Criterion Maximum
Concentration and the Criterion Continuous
.Concentration.
B. The Criterion Maximum Concentration
(CMC) is equal to one-half the Fina} Acute
„ Value. ,.
C. The Criterion Continuous Concentration
(CCC) is equal to the lowest of the Final.
Chronic Value or the Final Plant Value (if
available) unless other data (see section IX of
this appendix) show that a lower value
should be used. If toxicity is related to a
water quality characteristic, the CCC is
obtained from the Final Chronic Equation or
.Final Plant Value (if available) that results in
the lowest concentrations in the Usual range
of the water quality characteristic, unless ,
other data (see section DC) show that a lower
value should be used.
D. Round.hpth the CMC and the CCC to ,
two significant digits. " •
E. The criterion is stated as:
The procedures described in the Tier I
methodology indicate that, except possibly
where a locally important species is very
sensitive, aquatic organisms and their uses
should not be affected unacceptably if the
four-day average concentration of (1) does,
not exceed (2) ug/L more than once every
. three years on the average and if the one-hour
average concentration" does.not exceed (3) jig/
•L more than once every three years on .the
average.
where:
(1) = insert name of material
(2) = insert the Criterion Continuous
Concentration '-'..'•-
(3) = insert the Criterion Maximum
Concentration
XI. Final Review '..".'..-. ,
A- The derivation of the criterion should be
carefully reviewed by rechecking each step of
the Guidance. Items that should be especially
checked are: ;
1. If unpublished data are used, are they
well documented?
2. Are all required data available?
3. Is the range of acute values-for any
species greater than a factor of 10?
4. Is the range of Species Mean Acute
Values for any genus greater than a factor of
10? '
5. Is there more than a factor of 10
. difference between the four lowest Genus
Mean Acute Values?
6. Are any of the lowest Genus Mean Acute
Values questionable?
7. Is the Final Acute Value reasonable in:
comparison with the Species Mean Acute
Values and Genus Mean AcuteValues? ;
r 8. For any commercially or recreationally
important species'of the Great Lakes System,
is the geometric mean of the acute values •
from flow-through tests in which the
concentrations of test material were '
measured lower than the Final Acute Value?
9. Are any of the chronic values'
questionable? ' . :'"..'
10." Are any chronic values available for
acutely sensitive species?
11. Is the range of acute-chronic ratios
greater than a factor of 10? _
12. Is the Final Chronic Value reasonable •
in comparison with the available acute-and i
chronic data?. . <•. , • .-•
13. Is the measured or predicted chronic ,
value for any commercially or recreationally,
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21022 Federal Register. / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
Important species of the Great Lakes System
below the Final Chronic Value?
' 14. Are any of the oilier data important?
15, Do any data look like they might be
outliers?
18, A» thora any deviations from the
Guidance? Am they acceptable?
B. On the basis of all available pertinent
laboratory and field information, determine if
tho criterion Is consistent with sound
tctentific evidence. If it is not, another
criterion, cither higher or lower, shall be
derived u*!ng appropriate modifications of
this Guidance,
Methodology foe Deriving Aquatic life
Values; Ti»M
XII. Secondary Acute Value
If all eight minimum data requi
calculating an FAV using Tier I ai
Iuiraments for
are not met,
a Secondary Acute Value (SAV) for the
waters of the Great Lakes basin shall be
calculated for a chemical as follows:
To calculate a SAV, the iowast GMAV in
the database Is divided by the Secondary
Acute Factor (SAP] (Table A-l of this
appendix) corresponding to the number of
satisfied minimum data requirements listed
in the Tier I methodology (section III.B.1 of
this appendix). If all eight minimum data
requirements are satisfied, a Tier I criterion .
calculation may be possible. In order to
calculate a SAV, the database must contain,
at a minimum^ a genus mean acute value
(GMAV) for one of the following three genera
in the family Daphnidae—Cenodaphtua sp*
Daphnia sp., 6r Simocephalus sp.
If appropriate, the SAV wdll be made a
function of a water quality characteristic in
a manner similar to that described in Tier I
XIIL Secondary Acute-Chronic Ratio
If three or more experimentally determined
acute-chronic ratios ,(AC3?sJ, which are
acceptable based on Tier I, are available for
the chemical, determine the Final Acute-
Chronic Ratio PACK) using the procedure
described in Tier I. If fewer Jhan ithree
acceptable experimentally determined ACRs
are available, use enough assumad ACRs of
18 so that fee total -number of AGRs equals
three. Calculate the Secondary Acute-Chronic
Ratio (SACR) as &e geometric mean of the
three ACRs. Thus, if no experimentally
determined acute-chronic ratios are available.,
the SACR is 18.
XTV, Secondary Chronic Value
Calculate the Secondary Chronic Vafee
(SCV) using one -of the following:
A.
B,
scy=
scv=
' FAV
(use FAV from Tier I)
scv=
SACR
If appropriate, the SCV will be made a
function of a water quality characteristic in
a manner similar to that described in Tier I.
XV, Commercially or Rocreationally
Important Species
If for a commercially or rocreationally
important spades of the Great Lakes System
ttiB geometric moan of the acute values from
flow-through tests in which the
concentrations of the test materials were
measured Is lower than the calculated SAV,
thon that geometric mean must be used as the
SAV instead of the calculated SAV.
If fora commercially orrecreationally
Important species of the Great Lakes System
tho geometric moan of the chronic values
from flow-through tests in which the
concentrations, of the test materials were
measured is lower than the calculated SCV,
thon that goometric mean must be used as the
SCV Instead of the calculated SCV.
XVLTlwO Value
A, Secondary Value shall consist of -two
concentrations: the Secondary Maximum
ConoKitiatloa (SMC) and the Secondary
Continuous Concentration (SCO).
B. TJw SMC it equal to one-half of the
SAV.
C. Tho SCC If equal to the lowest of the
SCV oc tfao Final Want Vmlue, if available,
unless other data (See section DC of this
appendix} show that a lower value should be
usci
If toxicity is related to a water quality
characteristic, tha SCC is obtained from the
Secondary Chronic Equation or Final Plant
Valus, if available, that results in the lowest
concentrations in tha usual range of the water
quality characteristic, unless other data (See
section IX of this appendix) chow that a
lower valuo should be used.
D. Round both the SMC and the SCC to *wo
significant digits.
E. The value is Stated as:
The procedures described in the Tier H
methodology indicate that, except possibly
where a locally important species is very
sensitive, aquatic organisms should not be
affected unacceptably if the four-day average
concentration of (1) does not exceed (2) ,ug/
L more than once every three years on the
average and if the one-hour average
concentration does not exceed (3) ng/L more
than once every mree years on the average..
Where:
(l)=insert name of material
(2)=insertthe Secondary Continuous
Concentration
(3)=insert the Secondary Maximum
Concentration
XVII. Appropriate Modifications
On the basis of all available pertinent
laboratory and field information, determine if
the value is consistent with sound .scientific
evidence. If it is not, another value, either
higher or lower, must be derived using
appropriate modifications of these
procedures.
XVHL Availablity of Information
The most recent secondary values shall be
compiled on an annual basis by EPA Region
V Water Division and be available for
distribution to the public.
Tables to Appendix A to Part 132
TABJ.E A-l.—SECONDARY ACUTE
FACTORS
Number of satisfied minimum :
data requirements ,
1
2
3
4.
5
6,
7
0
...„.„.„-.„.„ 1
;. — ...„ ,.. ...,,
•AF
20
13
8.6
6,5
5,0
4.0
3.6
Appendix B to Part 132—Great Lakes
Water Quality Initiative Methodology
for Development of Bioaccumulation
Factors
• /. Introduction ,
The purpose iof this methodology is to
determine bioaccumulaHon factors to be used
in the calculation of Great Lakes Water
Quality Guidance (GLWGH3) human health
and wildlife Tier.I criteria and Tier II values.
The BAFs for human health criteria and
values will also be used to identify the
Bioaccumulative Chemicals of Concern
(BCCs) to be considered under the Great
Lakes Initiative (GLIJ programs.
Bioaccumulation reflects uptake of a
substance by aquatic organisms exposed to
the substance through all routes, as would
occur in nature. Bioconcentration reflects
uptake of a substance by aquatic organisms
exposed to the substance only from the
surrounding water medium. Both
bloaccumulatlon factors ;(BAFs) and
bioconcentration factors {BCFsj are
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Federal Register"/ Vol."-"5 8," Wo. ",72 7 FrMy, April 16, 1993 /Proposed Rules
21023
proportionality constants, relating the
- concentration of a substance in aquatic
organisms to its concentration in the . -
surrourfding water. BAFs, rather than BCFs.
will be used to calculate Tier I criteria and
Tier n values'because BAFs represent the
bioaccumulation that occurs in natural
aquatic systems. Measured BAEs will be used
when possible; otherwise, predicted BAFs
will be calculated, by multiplying a measured
or predicted BCF by a food chain multiplier
(FCM). . . • • , '
• II, Definitions , •
Bioaccumulation. The uptake and
retention of a substance by an aquatic ,
organism from its surrounding medium and'
food.
Bioaccum ulationfactor (BAF). The ratio
• (in I/kg) of a substance's concentration in
. tissue to its concentration in the surrounding
water in situations where both the organism
and its food are exposed and the ratio does
not change substantially oyer time.
Bioconcentration. The uptake and •
retention of a substance by an aquatic
organism from the surrounding water only,
through gill membranes or other external
body surfaces. •
Depuration. The loss of a substance from
an aquatic organism.
Food Chain Multiplier (FCM). A factor by
which a BCF is multiplied to obtain a BAF;
or, the ratio of the BAF to the BCF.
Octahol-vyater partition coefficient KM}. .
The ratio of the concentration of a substance
in the octanol phase to its concentration in
the aqueous phase in an equilibrate4 two-
phase octahol-water system.
Steady-State Bioconcentration Factor
(BCF). The ratio (L/kg) of a substance's
concentration in tissue to its concentration in
the surrounding water, in situations where
the organism is exposed through the water
only, and the ratio does not change
substantially over time; that is, a steady-state'
BCF exists when uptake and depuration are
equal. In this methodology whenever (he
term BCF is used, steady state is implied.
"Uptake. The sorptionof a substance into or .
onto an aquatic organism. ' . . -
in. Overview of Procedure, -
Bioaccumulation factors are, derived in the
" three ways listed below from most preferred •
to least preferred: ' ' _
A. A measured BAF based on a field study;
especially if the field study was'conducted
on the Great Lakes with fish at or near the -
top of the.aquatic food chain.
B. A predicted BAF that is the product of
a measured BCF from a laboratory study and
a food chain multiplier (FCM). -
C. A predicted BAF for organic chemicals
which is the product of a BCF estimated from
a log Km, and a FCM, where log means
logarithm to the base 10.
. BAFs for a chemical should be calculated
by as many of the three methods as available
data allow for comparative purposes. .The
' BAF selected is based on the stated
preferences unless there is a valid reason for
. selecting an alternative BAF. Formost .
inorganic chemicals, and many organic
."Chemicals, the FCM will be 1.0; that is,
, bioaccumulation and bioconcentration are '
equal. The lipid content of the test fish will
be used to normalize BAFs and BCFs for
organic chemicals so that data from different
tissues and fish species can be integrated. •
Fish are the dominant aquatic species
consumed by humans in the Great Lakes
basin. Thus, BAFs for human health Tier I
criteria and Tier n values will be based on
fish. Because Great Lakes basin wildlife
include many piscivorous species, BAFs for
wildlife criteria and values will generally be
based on fish data as well. Oh a case-specific
basis, wildlife BAFs may be weighted to
reflect the proportion of plants, invertebrates,
and fish in the diet of the species to be
protected.
IV. Review and Selection of Data
A. Data Sources. Measured BAFs.and BCFs
are assembled from available sources
including the following:
1. EPA Ambient Water Quality Criteria
documents issued after January 1,1980.
2. AQUIRE database.
3. Published scientific literature.
4. Reports issued by EPA or other reliable
sources.
5. Unpublished data. ,
B. Data Review.and Selection. Measured
BCFs and, if applicable, measured BAFs
should meet the procedural and quality
assurance requirements specified in the
ASTM (1990) "Standard Practice for
Conducting Bioconcentration Tests with
Fishes and Saltwater Bivalve Molluscs", and
in the U.S. EPA guidance contained in
Stephen et al. (1985) "Guidelines for
Deriving Numerical National Water Quality
Criteria for the Protection of Aquatic
Organisms and Their Uses". In particular, the
following should be met:.
1. The bioconcentration factor is steady-
state, or steady-state BCF can be estimated.
2. The concentration of the substance did
not have an adverse effect on the test
organisms. ,
3. The concentration of the substance in
the water was measured and was relatively
constant during the steady-state time period."
The concentration should be averaged over
the period during which steady-state
conditions were achieved. All average (mean)
values are geometric means unless specified
otherwise. .
4. For measured BCFs, the organisms were
exposed to the substance using a flow-
through or renewal procedure.
5. For organic chemicals, the percent lipid
was measured in, or can be reliably
determined for, the test organisms.
This methodology provides overall
guidance for the derivation of BAFs, but it
cannot cover all the decisions that must be
made in the review and selection of
acceptable data. Professional judgment is
required throughout the process. A degree of
uncertainty is associated with the
determination of any BAF or BCF. The •..
amount of uncertainty involved hi deriving a
BAF depends on both the quality of data
available and the method used to derive the
BAF.. :,•.•-...•• .
Field-measured BAFs should be based on
fish species, preferably living in the Great _..
Lakes at or near the top of the aquatic food
chain (trophic level 3 or 4). This is •
particularly true for organic chemicals with
log Row values greater than four. The
'conditions of the field study should not be
so unique that the BAF is not applicable to
other locations where the criteria and values
willapply.
Laboratory-measured BCFs also should be
based on fish species, but BCFs for molluscs
and other invertebrates maybe used with
caution. For example, because invertebrates
metabolize some chemicals less efficiently"-
than vertebrates, the BCF obtained with
invertebrates for such chemicals will be
higher than the BCF obtained with fish on a
lipid basis.
The percent lipid content of the test
organisms and the analytical method used to
measure lipids should be reported as part of
a BAF or BCF study on organic chemicals.
An average lipid value representative of
tissue in the test organisms should be used.
If percent lipid is hot reported for the test .
organisms in the original studyr it may be
obtained from the author; or, in the case of
a laboratory study, lipid data for the same
laboratory population of test organisms that
were us,ed in the original study may be used. •
If measured BCFs for a substance vary with
the test concentration of the substance in a
laboratory test, the BCF measured at the
lowest test concentration that is above
concentrations that exist in the control water
should be used; i.e.y do not use the BCF from
a control treatment
BAFs and BCFs should be used only if they
are expressed on a wet weight basis. BAFs ,
"'. and BCFs reported on a dry weight basis
should be converted to wet weight only if a
conversion factor was determined for the test
' organisms or comparable organisms from the
same study. •
Hereinafter in this methodology, the terms
'. BAF and BCF refer to those BAFs and BCFs'
that are consistent with the above provisions
for data review and selection. . ,
V. Determination of BAFs for Inorganic
Chemicals
BAFs are assumed to be equal to BCFs for
most inorganic substances. However, a food
chain multiplier may be applicable to some
metals, for example, if an organometallic
form of the metal biomagnifies.
Concentrations of an inorganic substance
in a BAF or BCF study should be greater than
nonrtal background levels and greater than
levels required for normal nutrition of the
test species if the substance is a
micronutrient, while still below levels which
adversely affect the species. Bioaccumulation
of inorganic substances may be . •
inappropriately overestimated if
concentrations are at or below normal •
background levels due to, for example,
nutritional requirements of the test
organisms. ..;.- ', .
A. BAF for Human Health Criteria and
Values, / -' , • "
1. BAFs and BCFs used to determine
human health BAFs should be based on
edible tissue (e.g., muscle) of freshwater fish'
unless it can be demonstrated that whole
body BAFs or BCFs are similar to edible
tissue BAFs or BCFs. BCFs for non-fish ,
species and non-edible tissues offish are , '
generally higher than for muscle of fish.
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21024
Federal Register / VoL 58, No. 72 / Friday, April 16, 1993 / Pjsopo&ed
Thesa other BCFs and BAFs should only be
used to set upper limits on the BCF or BAF
for odibls tissues. Plant BCFs and BAFs
should not boused for human health criteria
and values.,
2.If ono or more measured BAFs are
available for am Inorganic chemical the
geomeMc mean of those BAFs will be used.
3, A predicted BAF used to derive human
health criteria and values equals an odibla-
porfton BCF times a food chain multiplier. If
tr.ora Una one edible-partksa BCF is
available, the geometric mean of those values
wIU bo used. The food chain multiplier will
bo 1.0 unless chemical specific
Momtgnlfiottioa data support using a
multiplier other thaa 1.0.
B. BAF for Wildlife Criteria and Values
1. BAFs «ad BCFs used to determine
wildlife criteria and values should be based
on wholo-body fish data unless it can be
demonstrated that, BAFs or BCFs for edible
Uf tut, arc similar to whole body BAFs or
BCFs. BCFs Kid BAFs for non-fish species
a:sd aoBHXliblft tissues of fish are generally
higher OUB for muscle of fish. The BCFs and
BAFs for non-fish species and non-edible
t braes of fish should only be used to sot
lower limits oa the desired BCF or BAF for
whole body.
2. if ono armors measured BAFs are
tvxiUbk, the goomfttricmean of those BAFs
will be used.
3. A pwdicted BAF used to derive wildlife
criteria tad values equals a whole-body BCF
times a food chain multiplier. If more than
oca whole-body BCF Is available, the
gtonsetric meaa will be uisd. The food chain
multiplier will bo 1.0 unless chemical
specific biotnagnification data support using
a multiplier other than 1.0.
4, BAFs or BCFs, used to determine
wildlife criteria and values, for whole-body
fish, Invertebrates and aquatic plants may ba
considered oa a cass-by-case basis. If used.
they should be used in proportion to the
percent-by- weight of invertebrate or plant
material consumed by the wildlife species to
be protected.
ViT. Detent/notion of BAFs for Organic
Cltemicals
A, LipSd Nonntlizttloa
For lipophillc organic chemicals, BAFs and
BCFs are at fumed to be directly proportional
to the percent lipid from ono tissue to
another aad frota one aquatic species to
another, Percent lipid data are used to
convert reported BAFs and BCFs to BAFs and
BCFs appropriate for tha fisheries of the
Groat Lakes basin, Percent lipid data are also
used to determine human health and wildlife
BAFs from the simo data.
The percent lipid of the test organism
(whole body credible tissue) should be
obtained from the BAF or BCF study. BAFs
and BCFs are normalized to one percent lipid
by dividing the BAFs or BCFs by the mean
percent lipid. Both whole body and edible
tissue BAFs and BCFs are normalized using
lha respective whole body and edible tissue
percent lipid values. Unless comparability
can ba determined, the percent lipid should
be determined on the test organisms.
B. Food -Cham Multiplier
In the absence of measured BAFs for
organic chemicals, a food chain multiplier
(FCM) is -used to predict the BAF. 'The
appropriate FCM is selected from Table 1
based on the chemical's log KOW. A FCM
greater than 1.0 is applicable to most
lipophHic organic chemicals with log KOW
values of four or more. For human health
BAFs, a FCM from Table 1 for trophic level
4 (top predator fish) is used. For wildlife
BAFs, FCMs for trophic levels 3 (small fish)
and 4 are used depending on the model bird
or mammal being considered. For
superlipophilic chemicals, i.e., log Kow
greater than 6.5, chemical-specific
information should be used to determine the
appropriate FCM to use because the FCM
may range from 0.1 and 100. In the absence
of chemical-specific information, a FGM of
one should be used.
C. Predicted BCFs Based on Qclanol-Water
Partition Coefficient
In the absence of acceptable measured
B AFs-and/or BCFs for lipophilic organic
chemicals, a BAF is calculated using the
relationship between the BCF and the log of
the octanol-water partition coefficient. BCFs
based on log Kow values will be multiplied
by tie appropriate FCM to reflect
a. Human Health BAE=»(mean normalized
BCF) (5.0) {FCMJ
b. Wildlife BAF=et
al. (1985) "Guidelines for Deriving Numerical
National Water Quality Criteria for the
Protection of Aquatic Organisms andThefc
Uses." NTIS # PB85-227049. U.S.
Department of Commerce, 5285 Port Royal
Road, Springfield, VA 22161.
ASTM. 1990, Standard Practice for
Conducting Bioeoncentration Tests with •
Fishes and .Saltwater Bivalve Molluscs.
_ Designation E 1022—84. Pages 606-62 2. ife
Annual Book of ASTM Standards. Section
11, Water and Environmental Xechnologyj
Volume 11.04. American Society for Testing
and Materials, t'916 Race 'Street, Phila. PA
19103.
Thomann, R.V, 1989. Bioaccumulation
Model of Organic Chemical Distribution In
Aquatic Food Chains, .Environ. Sci. Teehnol.
23: 699-707.
UJS. Environmental Protection Agency. .
1991. Assessment and Ceotroi af '
Bioconcentratable 'Contaminants in Surface
Waters, Draft 0.S. EPA, Office of Water.,
Permits Division, EN-336, 401 MSbreet,
Washington DC 20480. ,
Veith, G.D. and P. Kosian. 1983. Estimating
Bioconcentration Potential from Octanol/
Water Partition Coefficients, Chapter 15 in '
PCBs in the Craat Lakes. Mackay, D.,. R.
Patterson, S. Eisenreich, , and M. Simmons ,
(eds.) Ann Arbor Science, Publishers, Ana j
Arbor, Michigan. , 1
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
2102a
Tables to Appendix B of Part 132
TABLE B-1.—AQUATIC FOOD CHAIN
MULTIPLIERS
LogKcw
:£3.9
4.0
4.1
4.2
4.3
•4.4
4.5
4.6
4.7
4.8
4.9
. 5.0
5.1
5.2
'. 5.3
,5.4
5.5
5.6
5.7
5.8
5.9
6.0
6.1
, 6.2
6.3
6.4
6.5
>6.5
Trophic Level"
2
1.0
1.1
1.1
1.1
1.1
• "1.2"
1.2
1.2
1.3
1.4
1.5
1.6
1.7
1.9
2.2
2.4
2.8
3.3
3.9
4.6
5.6
6.8
8.2
10
13
15
19
(")
3
1.0
1.0
1.1
1.1
1.1
1.1
1.2
1.3
1.4
1.5
1.8
2.1
2.5
3.0
3.7
4.6
5.9
7.5
9.8
13
17
21
25
29
34
39
45
(b)
4
1.0
1.0
1.1
1.1
1.1
1.1
1.2
1.3
1.4
1.6
2.0
2.6
3.2
4.3
5.8
8.0
11
16
23
33
47
67
75
84
92
98
100
(")
"Trophic level: 2 Is zooplankton, 3 Is small
fish, 4 is piscivorous fish including top
predators.
. b For chemicals with log Kow values greater
.than 6.5 the FCM can range from 0.1 to 100.
Such chemicals should be evaluated
individually to determine the appropriate FCM.
In the absence of chemical-specific
information, a FCM of 1.0 should be used.
Appendix C to Part 132—Great Lakes
Water Quality Initiative Methodology
for Development of Human Health
Criteria and Values
J. Introduction
A. Goal
The goal of the human, health criteria for
the Great Lakes System is the protection of
humans from unacceptable exposure to
toxicants via consumption of contaminated
fish and drinking water and from ingesting
water as a result of participation hi water-
oriented recreational activities.
B. Levelof Protection
The criteria developed shall provide a level
of protection likely to be without appreciable
risk of carcinogenic and/or non-carcinogenic
effects. Criteria are a function of the level of
.design risk or no adverse effect estimation,
selection of data and exposure assumptions.
Ambient criteria for single carcinogens shall
not be set at a level representing a lifetime
incremental risk greater than one in 100,000
of developing cancer using the hazard
assessment techniques and exposure
assumptions described'herein. Criteria
affording protection from noncarcinogenic
effects shall be established at levels that,
taking into account uncertainties, are
considered likely to be without an
appreciable risk of adverse human health
effects (i.e., acute, subchronic and chronic
toxicity including reproductive and
developmental effects) during a lifetime of
exposure, using the risk assessment
techniques and exposure assumptions
described herein.
C. Two-tiered Classification
Chemical concentration levels in surface
water protective of human health shall be
derived based on either a Tier I or Tier n
classification. The two Tiers are primarily '.
.distinguished by the amount of toxicity data
available for deriving the concentration
levels.
n. Minimum Data Requirements
The best available toxicity data on the
adverse health effects of a chemical shall be
used when developing Tier Icriteria or Tier
H values. The best available toxicity data
shall .include data from well conducted
epidemiolpgic and/or animal studies which
provide (in the case of carcinogens) an
adequate weight of evidence of potential.
human carcinogsnicity and, in the case of
non-carcinogens, a dose response
relationship involving critical effects
biologically relevant to humans. Such
information should be obtained from the EPA
Integrated Risk Information System (IRIS)
database, the scientific literature, and other
informational databases, studies and/or
reports containing adverse health effects data'
of adequate quality for use in this procedure.
Strong consideration shall be given to the
most currently available guidance provided
by IRIS ia deriving criteria or values,
supplemented with any recent-data not
incorporated into IRIS. ;
A. Carcinogens
Tier I criteria and Tier n values will be
derived pursuant to section III. A of this
appendix when there is adequate evidence of
potential Tinman carcinogenic effects for a
chemical.' It is strongly recommended that
the EPA classification system for chemical
carcinogens,-which is described in the 1986
EPA Guidelines for Carcinogenic Risk
Assessment (U.S. EPA. 1986), or future
modifications thereto, be used in determining
whether adequate evidence of potential
carcinogenic effects exists.
1. Tier I: Weight of evidence of potential
human carcinogenic effects sufficient to :
derive a Tier I human cancer criterion shall
generally include human carcinogens, and
probable human carcinogens. Chemicals are
described as human carcinogens when there
is sufficient evidence from epidemiologieal
studies to support a causal association
between exposure to the agents and cancer.
Chemicals described as probable human
carcinogens include agents for which the
weight of evidence of human carcinogenicity
based on epidemiological studies is limited.
Probable human carcinogens are'also agents
for which there is sufficient evidence from
animal studies and for which there is -
inadequate evidence or no data from
epidemiologic studies. Possible human
carcinogens, may be suitable for Tier I
criterion development Vrhere studies have
been well-conducted albeit are limited, when
• compared to studies Used in classifying
human and probable human carcinogens,
because they involve only a single species,
strain or experiment which does not
demonstrate a high incidence, unusual site or
type of tumor, or early onset. Possible human
carcinogens are agents with limited evidence
of carcinogenicity in animals in the absence
of human data. Limited evidence includes a
wide variety of evidence, e.g., (a) a malignant
tumor response ha a single well-conducted
experiment that does not meet conditions for
sufficient evidence, (b) tumor response of
marginal statistical significance in studies
having inadequate design Or reporting, (c)
benign but not malignant tumors with an
agent showing no, response in a variety,of
short-term tests for mutagenicity, and (d)
response of marginal statistical significance
hi a tissue known to have a high or variable
' background rate.
a. The weight of evidence for
carcinogenicity from studies in humans is
classified as:
i. Sufficient when the evidence indicates
that there is a causal relationship between
the agent and human cancer.
ii. Limited when the evidence indicates
that a causal interpretation is credible, but
that alternative explanations, such as chance,
bias, or confounding, could not adequately be
excluded.
iii. Inadequate when the evidence indicates
that one of two conditions prevailed:
(a) There were few pertinent data, or
(b) The available studies, while showing
evidence of association, did not exclude
chance, bias, or confounding and therefore a
causal interpretation is not credible.
b. The weight of evidence for
carcinogenicity from studies in experimental
animals is classified as:
i. Sufficient when the evidence indicates
that there is an increased incidence of
malignant tumors or combined malignant
and benign tumors:
(a) In multiple species or strains; '".'•-
(b) In multiple experiments (e.g., with
different'routes of administration orusing
different dose levels); or •
(c) To an unusual degree in a single
experiment with regard to high incidence,
unusual site of type of tumor, or early age at
onset.
Additional evidence maybe provided by data
: on dose-re'sponse effects, as well as
information from short-term tests or on .
chemical structure.
ii. Limited when the data suggest a
carcinogenic effect but are limited because:
(a) The studies involve a single species,
strain, or experiment and do not meet criteria
for sufficient evidence (see preceding
paragraph); or '--
(b) The experiments are restricted by
inadequate dosage levels, inadequate
duration of exposure to the agent, inadequate
period of follow-up, poor survival, too few
animals, or inadequate reporting; or
(c) The studies indicate an increase in the
incidence of benign tumors only.
iii. Inadequate when; because of major
qualitative or quantitative limitations, the
evidence cannot be interpreted as showing
either the presence or absence of a
carcinogenic effect. •
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Federal Register / Vol. 58, No. 72 /Friday, April 16, 1993 / Proposed Rules
2, Tier 11: Welght-of-ovidencB of possible
human carcinogenic effects sufficient to
derive a Tier H human cancer value shall
include thosa possibla human carcinogens,
with da'.a sufficient for quantitative risk
assessment, however inadequate for Tier I
criterion development due to a tumor
response of marginal statistical significance
or iBibility to derive a strong dose-response
relationship.
B. Noaeareinogens
All available toxicity data shall he
evaluated considering the full range of
possible health effects of a chemical, i.e.,
acute/subtcute, chronic/subchronic and
reproductive/developmental effects, in order
to oest describe the dose-response
relationship of the chemical, and to calculate
human noncancor criteria and values data
•which will protect against the most sensitive
endpo!nt(s) of toxicity. Although it is
desirable to have an extensive database
which considers a wide range of possible
adversa effects, this type of data exists for a
very limited number of chemicals. For many
others, there is a range in quality and
quantity of data available. To assure
minimum reliability of criteria and values, it
Is necessary to establish a minimum database
below which development of criteria or
values cannot proceed. The following,
although not idoal, represent the minimum
data sets necessary for this procedure.
1. Tfcf /; The minimum data sufficient to
derive a Tier I human criterion shall include
at least pne, well-conducted opidemiologic
study or animal study- A well-conducted
epldemlologic study for a Tier I human
noncsneef" criterion must quantify exposure
levol(s) and demonstrate positive association
between exposure to a chemical and adverse
effects) in humans. A well-conducted study
in animals must demonstrate a dose response
relationship involving one or more critical
offect(s) biologically relevant to humans. (For
cxamplo, study results from an animal whose
phannacokinetics and toxicokinetics match
those of a human would be considered most
biologically relevant.) Ideally, the duration of
a study should span multiple generations of
exposed test species or at least a major
portion of the lifespan of one generation.
This type of data is currently very limited. By.
tho uss of uncertainty adjustments, shorter,
term studios (such as 90-day subchronic
studios) with evaluation of more limited
cffec'(s) may be used to extrapolate to longer
exposures or to account for a variety of
adverse offsets. For Tier I criteria developed
pursuant to this procedure, such a limited
study must be conducted for at least 90 days
Jn rodents or 10 percent of the lifespan of
other appropriate test species and
demonstrate a no observable adverse effect
level (NOAEL). Chronic studies of one year
or longer in rodents or 50 percent of the
lifespan or greater in other appropriate test
species that demonstrate a lowest observable
adverse effect level (LOAEL) may be
sufficient for use in Tier I criterion derivation
if tho effects observed at the LOAEL were
relatively mild and reversible as compared to
effects at higher doses. This does not
preclude tho use of a LOAEL from a study
with only one or two doses if the effects
observed appear minimal when compared to
effect levels observed at higher doses in other
studies.
2, r/erff: When sufficierit data are not -
available to meet the Tiefl data
requirements, a more limited database may
be considered for Tier II values development.
As with Tier I, all available data shall be
considered and ideally should address a
range of adverse health effects with exposure -
over a substantial portion of the lifespan (or
multiple generations) of the test species.
When such data are lacking it may be
necessary to rely on less than ideal data in
order to establish a Tier II value. .With the use
of appropriate uncertainty factors to account
for such limited data, the minimum data
sufficient to derive a Tier n value shall
include a NOAEL from at least one well-
conducted short-term repeated dose study.
This study shall be of at least 28 days
duration, in animals demonstrating a dose-
response, and involving effects biologically
relevant to humans. Data from studies of
longer duration (greater than 28 days) and
LOAELs from such studies may be more
appropriate in some cases for derivation of
Tier II values." Use of a particular LOAEL
should be based on consideration of the
following information: severity of effect,
quality of the study and duration of the
study. An additional uncertainty factor may
be applied to a LOAEL or NOAEL in addition
to the standard uncertainty factors which
account for intra- and interspecies variability
(and for a lack of an identifiable NOAEL
when a LOAEL is used), in order to further
accommodate the extrapolation of short
study duration (28 days) to lifetime exposure
and to compensate for the lack of a complete
toxicological data base. Structure-activity
relationships (S AR) may be used along with
all other data available on a chemical to
determine the appropriate additional
uncertainty factor to be used with such
limited data.
Iff. Principles for Development of Tier I
Criteria or Tier II Values
The fundamental components of the
procedure to calculate Tier I criteria or Tier
II values are the same. However, certain of
the aspects of the procedure designed to
account for short-duration studies or other
limitations in data are more likely to be
relevant in deriving Tier II values than Tier
I criteria.
A. Carcinogens
1. A non-threshold mechanism of
carcinogenesis shall be assumed unless
biological data adequately demonstrate the
existence of a threshold on a chemical-^
specific basis.
2. All appropriate human epidemiologic
data and animal cancer bioassay data shall be
considered. Data specific to an
environmentally appropriate route of
- exposure shall be used. Oral exposure should
be used preferentially over dermal and
inhalation. The risk associated dose shall^be
set at a level corresponding to an incremental
cancer risk of one in 100,000. If acceptable
human epidemiologic data are available for a
chemical, it shall.be used to derive the risk
associated dose. If acceptable human
epidemiologic data are not available, the risk
associated dose shall be derived from
available animal bioassay data. Data from a
species that responds most like humans is
preferred where all other considerations
regarding quality of data are equal. For
example, in'the absence of data to distinguish
the most relevant species, data from the most
sensitive species tested, i.e., the species
showing a carcinogenic effect at the lowest .
administered dose, shall generally be used.
3. When animal bioassay data are used and
a non-threshold mechanism of
carcinogenicity is assumed, the data are fitted
to a linearized multistage computer model
(e.g, Global "86 or equivalent model). Global
'86 is the linearized multistage model,
derived by Howe, Crump and Van
Landingham (1986) which EPA uses to .
determine cancer potencies. The upper-
bound 95 percent confidence limit on risk
(or, the lower 95 percent confidence limit on ,
dose) at the one in 100,000 risklevel shall
be used to calculate a risk associated dose
(RAD). Other models, including
modifications or variations of the linear
multistage model which consider the data
more appropriately may be used on a case-
by-case basis.
4. If the duration of experiment is
significantly less than the natural lifespan of
the test animal (for example, as cited in the
Human Health TSD, 78 weeks for mice and
90'weeks for rats), the slope will be adjusted
to compensate for latent tumors which were
not expressed (see, e.g., U.S. EPA, 1980.)
5. A species scaling factor shall be used to
account for differences between test species
and humans. It shall be assumed that
milligrams per surface area per day is a«
equivalent dose between species (U.S. EP/,.
1986). All doses presented in mg/kg ,
bodyweight will be converted to an
equivalent surface area dose by raising the
mg/kg dose to the % power. However, if ,
adequate pharmacokinetic and metabolism
studies are available, these data may be
factored into the adjustment for species
differences on a case-by-case basis.
6. Additional data selection and
adjustment decisions must also be made in
the process of quantifying risk. Consideration
must be given to tumor selection for .
modeling, e.g., pooling estimates for multiple
tumor types and identifying and combining -
benign and malignant tumors. All doses shall
be adjusted to give an average daily dose over
the study duration. Adjustments in the rate
of tumor response must be made for early
mortality in test species. The goodness-of-fit
of the model to the data must also be
assessed.
7. When a linear, non-threshold dose
response relationship is assumed, the risk
associated dose shall be calculated using the
following equation:
RAD =
0.00001
Where: '
RAD = risk associated dose in milligrams
of toxicant per kilogram body weight per day
(mg/kg/day).
0.00001 (1 x 10-3) = incremental risk of
developing cancer equal to one in 100,000.
-qi* = slope factor (mg/kg/day)~'.
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Federal Register / Vol.'58, No. 72 I Friday, April 16, 1993 / Proposed Rules 21027
8. If human epidemiologic data and/or
other biological data (animal] indicate that a
chemical causes cancer via a threshold
mechanism, the risk associated dose may be
calculated via a method which assumes a
threshold mechanism is operative on a case-
by-case basis.
B. Noncarcinogens " v-
1. Noncarcinogens shall generally be
assumed to have a threshold dose or
concentration below which no adverse effects
should be observed^Therefore, the Tier I
criterion or Tier II value is the maximum
water concentration of a substance at or
below which a lifetime exposure from
drinking the water, consuming fish caught in
the water, and ingesting water as a result of
• participating in v?ater-related recreation
activities is likely*to be without appreciable
risk of deleterious effects.
For some rioncarcinogens, there may not be
a threshold dose below which no adverse
effects should be observed. Chemicals acting
as genotoxic teratogens and germline
mutagens are thought to possibly produce
reproductive and/or developmental effects
via a genetically linked mechanism which
may have no threshold. Other chemicals; also
may not demonstrate a threshold. Criteria for
these types of chemicals will be established
on a case-by-case basis using appropriate
assumptions reflecting the likelihood that no
threshold exists.
2. All appropriate human and animal
tpxicologicdata shall be reviewed and
evaluated. Exposure should be via a route
most relevant to environmental exposure.
When acceptable human data are not
available (e.g., well-conducted epidemioldgiG
studies), animal data from species most
biologically relevant to humans shall be
used. In the absence of data to distinguish the
most relevant species, data from the most
sensitive animal species tested, te., the
species showing a toxic effect at the lowest
administered dose (given a relevant route of
exposure), shall generally be used.
3. Minimum data requirements are
specified in section n.B of this appendix. The
experimental exposure level representing the
highest level tested at which no adverse
effects were demonstrated (NOAEL) from
studies satisfying the provisions of section
n.B of this appendix shall be used for criteria
calculations. In the absence of a NOAEL, the •
lowest observable adverse effect level
(LOAEL) from studies satisfying the _.'••- .
provisions of section n.B of this appendix
may be used if it is based on relatively mild
and reversible effects.
4, Uncertainty factors shall be used to
account for the uncertainties in predicting -
acceptable dose levels for the general human
population based upon experimental animal
data or limited human data. -
a. An uncertainty factor of 10 shall
generally be used when extrapolating from
valid experimental results from studies on
prolonged exposure to average healthy .
humans, this 10-fold factor is used to protect
sensitive members of the human population,
b. An uncertainty factor of 100 shall
generally be used when extrapolating from
valid results of long-term studies on
experimental animals when results of studies
of human exposure are not available or are
inadequate. In comparison to a, above, this
represents an additional 10-fold uncertainty
factor in extrapolating data from the average
animal to the average human.
. c. An uncertainty factor of up to 1000 shall
generally'be used when extrapolating from
animal studies for which the exposure -
duration is less than chronic or when other
significant deficiencies in study quality are
present, and when useful long-term human
data are not available. In comparison to b,
above, this represents an additional
uncertainty factor of up to 10-fold. The level
of additional uncertainty applied for
subchronic exposure depends on the
^duration of the study used relative to the
lifetime of the experimental animal.
d. An additional uncertainty factor of
between one and ten may be used when
deriving a criterion from a lowest observable
adverse effect level (LOAEL). This
uncertainty factor accounts for the lack of an
identifiable no observable adverse effect level
(NOAEL). The level of additional uncertainty
applied may depend upon the severity of the
observed adverse effect. '
e. An additional uncertainty factor of
between one and ten may be applied when
there are limited effects data or incomplete
subacute or chronic tqxicity data. The level
of quality and quantity of the experimental
data available as well as structure-activity
relationships may be used to determine the
factor selected. ,
£ When deriving an uncertainty factor in
developing a Tier I criterion or Tier n value,
the total uncertainty, as calculated following
the guidance of 4.a-e, cited above, shall not
exceed 30,000. •
5. All study results shall be converted, as
necessary, to the standard unit for acceptable
daily exposure of milligrams of toxicant per
kilogram of body weight per day (mg/kg/day)..
Doses will be adjusted for continuous
exposure, i.e., seven days/week, 24 hours/
day, etc. ,
C. Criteria and Value Derivation
1. Standard Exposure Assumptions. The
following represent the standard exposure
assumptions used to calculate Tier! criteria
and Tier II values for carcinogens and
noncarcinogens. Higher levels of exposure
may be assumed by States and Tribes t
pursuant to CWA section 510, or-where '
appropriate in deriving site-specific criteria
pursuant to procedure 1 in appendix F to
part 132.
Wh = weight of an average human
(Wh = 70kg).
. WCd = per capita water consumption .
(both drinking and incidental exposure)
for surface waters classified as public -
water supplies = two liters/day.;
or
WC, = per capita incidental daily
water ingestion for surface waters not
used as human drinking water sources
= 0.01 liters/day.
FG = per capita daily consumption of
regionally caught freshwater fish =
0.015 kg/day. .
B AF = bioaccumulation factor, as
derived using the BAF methodology in
appendix B to part 132.
2. Carcinogens. The Tier I human
cancer criteria or Tier n values shall be
calculated as follows:
HCV = -
RADxWh
WC-f (EC x BAF)
Where: ;, -,'_.. . : ,
HCV = Human Cancer Value in
, milligrams per liter (mg/L).
RAD = Risk associated dose in
, milligrams toxicant per kilogram body
weight per day (mg/kg/day) that is
associated with a lifetime incremental
cancer risk equal to one in 100,000.
Wh = weight of an average human •
(Wh=70kg).
WCd = per capita water .consumption
(both drinking and incidental exposure)
for surface waters classified as public
water supplies = two liters/day.
•or ;•'-• -. .•••'• -i' ''•.'"" • :
WCr = per capita incidental daily
water ingestion, for surface waters not
used as human drinking water sources
= 0.01 liters/day.
FC = per capita daily consumption of
regionally caught freshwater fish - .
0.015 kg/day.
BAF = bioaccumulation factor; as •'
derived using the BAF methodology in
appendix B to part 132.
3. Noncarcinogens. The Tier I human
noncancer criteria or Tier n values shall
be calculated as follows:
HNV =
ADExWhxRSC
WC+(FCxBAF)
'Where: . '.''•- ; ;
HNV = Human noncancer value in
milligrams per liter (mg/L). ','•
ADE = Acceptable daily exposure in
milligrams toxicant per kilogram body -
weight per day (mg/kg/day).
RSC = Relative source contribution
factor of 0.8 for bioaccumulative
chemicals of concern. This shall be
applied to bioaccumulative chemicals of
concern. •
. Wh = weight of an average human
(Wh=70kg).
WCd = per capita water consumption
(both drinking and incidental exposure)
for surface waters classified as public
watersupplies = two liters/day.
or
WCr = per capita incidental daily
water ingestion for surface waters not •
used as human drinking water sources
= 0.01 liters/day.
FC = per capita daily consumption of
regionally caught freshwater fish =
0.015 kg/day. v
BAF = bioaccumulation factor, as •
derived using the BAF methodology in
appendix B to part 132.
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21028 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
IV. nefarences
Howa, R.B,, K.S. Crump and C. Van
Landingham. 1986, Computer Program to
Extrapolate) Quantitative Animal Toxicity
Data to Low Doses, Prepared for EPA under
subcontract #2-25lU-2745 to Research
Triangle Institute.
U.S, Environmental Protection Agency.
1980. Water Quality Criteria Availability,
Appendix C Guidelines and Methodology
Used in the Preparation of Health Effects
Assessment Chapters of the Consent Decree
Water Quality Criteria Documents. Available
from U.S. Environmental Protection Agency,
OHlco of Water Resource Center (WJS-550A),
401M St., SW., Washington, DC 20460.
U.S. Environmental Protection Agency.
1986. Guidelines for Carcinogen Risk
Assessment. Available from U.S,
Environmental Protection Agency, Office of
Water Resource Center (WH-S50A), 401 M
St., SW., Washington, DC 20460.
Appendix D to Part 132—Great Lakes
Water Quality Initiative Methodology
for the Development of Wildlife Criteria
and Values
I, Introduction
A Groat Lakes Water Quality Wildlife
Criterion (GLWC) is the concentration of a
substance which, if not exceeded, protects
avian and mammalian wildlife populations
Inhabiting the Great Lakes basin from adverse
effects resulting from the ingestion of surface
•waters and aquatic prey taken from surface
wafers of the Groat Lakes System. These
criteria are numeric or narrative in nature
and are based on existing toxicologies!
studies of the substance of concern and
quantitative information about the exposure
of wildlife species to the substance (i.e., food
and water consumption rates). Since
toxkologictl and exposure data for
Individual wildlife species is limited, a
GLWC is derived using a methodology
similar to that used to derive noncancer
human health criteria (Barnes and Dourson,
1988; NAS. 1977; NAS, 1980; U.S. EPA.
1980). Separate avian and mammalian values
are developed using taxonomic class-specific
toxicity data and exposure data for five
representative Groat Lakes basin wildlife
gpcdes. The representative wildlife species
selected are representative of avian and
mammalian species resident in the Great
Lakes basin which are likely to experience
significant exposure to contaminants through
the aquatic food web; they are the bald eagle,
osproy. belted kingfisher, mink, and river
otter. Taxonomic class-specific avian and
mammalian Wildlife Values (WVs)—
concentrations of a substance which if not
exceeded should protect the wildlife
species—are calculated using the geometric
moans of the species' WVs and the lower of
the mammalian and avian WVs is selected as
thoGLWC.
This appendix establishes a two-tiered
approach to the protection of avian and
mammalian communities in the Great Lakes
basin. This appendix sets forth the method
for deriving both Tier I criteria and Tier n
values.
n. Calculation of Wildlife Values for Tier I
Criteria and Tier U Value Development
Table 4 of part 132 and Table D-l of this
appendix to part 132 contain the proposed
Tier I criteria calculated by EPA pursuant to
the provisions below. No Tier II values have
been calculated.
A. Equation for Avian and Mammalian
Wildlife Values"
The Tier I GLWC is the lower of the two
taxonomic class-specific wildlife values. A
Tier H value may be based on the wildlife -
value derived from a single taxonomic class.
These wildlife values are calculated using the
equation presented below.
wv=
[NOAELxSSF]xWtA
WA+[FAXBAF]
Where:
WV = Wildlife value in milligrams of
substance per liter (mg/L).
NOAEL = No observed adverse effect
level in milligrams of substance per
kilogram of body weight per day (mg/kg-
d) as derived from mammalian or avian
studies as described in section II.E of
this document,
WIA = Average weight in kilograms
(kg) for the representative species
identified for protection or the species
identified as requiring greater
protection.
WA = Average daily volume of water
consumed in liters per day (L/d) by the
representative species identified for
protection or the species identified as
requiring greater protection.
SSF = Species sensitivity factor. An
extrapolation factor to account for
differences in toxicity between species.
Further information is provided in
section ELI of this document.
FA = Average daily amount of food
consumed in kilograms per day (kg/d)
by the representative species identified
for protection or the species identified
as requiring greater protection.
BAF = Aquatic life bioaccumulation
factor for wildlife in liters per kilogram
(L/kg). Chosen using guidelines for
wildlife presented in appendix B to part
132, Methodology for Development of
Bioaccumulation Factors.
The term "wildlife value" is used to denote
any value which results from each
application of the equation presented above
or any averaging of such numbers. It can refer
to values derived using either the Tier I or
Tier n database requirements. Wildlife values
calculated for the representative species are
used to calculate taxonomic class-specific
wildlife values. "Tier II wildlife value," or
"Tier II value," is used to denote any final
number derived from data meeting only the
Tier n requirements and using the procedure
presented in this document. "Tier I wildlife
value," or Tier I value," is used to denote any
final number derived from.data meeting .the.
Tier I database requirements calculated using
the procedure presented in this document. <
"Tier I criteria" are the four wildlife criteria
presented in Table 4 of part 132 and in Table
D-l of this appendix to part 132,
B. Identification of Representative Species for
Protection
Piscivorous species are identified as the
focus of concern for wildlife criteria
development in the Great Lakes, An analysis
of known or estimated exposure components
for avian and mammalian wildlife species is
presented in the Technical Support
Document for Wildlife Criteria (U.S. EPA,
1993a). This analysis identifies three avian
species and two mammalian species as
, representative species for protection. The
NOAEL obtained from toxicity data for each
taxonomic class is used to calculate Wildlife
Values (WVs) for each of the five
representative species identified for
protection.
Because of the lack of empirical species-
specific exposure information for all wildlife
species in each taxonomic class, the
geometric means of wildlife values for the
representative species within each taxonomic
class are used to determine the taxonomic
class-specific wildlife value.
C. Identification of Species Requiring Greater
Protection '
If exposure and/or hazard data identifies a
Great Lakes basin avian or mammalian
wildlife species which is at risk, for which
the wildlife criteria or Tier II value based on
the representative species may not be
adequately protective, the final avian or
mammalian WV will be calculated
specifically for that species. A class-specific
WV for a species determined to require
greater protection is calculated using the
equation presented above, but using exposure
information for the species determined to
require greater protection. Toxicity
information specific for that species is .also
used if it is available. This provision can be
invoked in the derivation of site-specific
criteria where a wildlife species has been
determined to require greater protection.
D. Calculation of Avian and Mammalian
Wildlife Values
The taxonomic class-specific Wildlife .
Values (WV) can be determined in two wayd
both of which use the equation presented
above. The avian WV is the geometric mean
of the WVs calculated for the three
representative avian species identified for
protection or it is the WV calculated for an
avian species determined to require greater
protection. The mammalian WV is the
geometric mean of the WVs calculated for the
two representative mammalian species or it
is the WV calculated for a mammalian
species determined to require greater
protection. When a WV is calculated for a
species determined to require greater
protection, the taxonomic class-specific WV
. for use hi the determination of a GLWC is the
lower of the WVs 'calculated for the given
taxonomic class (the geometric mean of the
WVs calculated for the representative species
or the WV calculated for the species
determined to require greater protection).
The Tier I GLWC is set equivalent to the
lower of the avian or mammalian WVs
determined,
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Federal Register / Vol. 58, No. 72 7 Friday, April 16, 1993 / Proposed Rules
21029
Iff. Parameters of the Hazard.Component of
the Wildlife Criteria Methodology
A. Definitions
The following definitions provide
additional specificity and guidance in the "-. •
' evaluation of toxieity data and the
application of this methodology. These
definitions are applicable to both Tier I
criteria and tier fl value development.
Acceptable eridpoints. For the purpose of
wildlife criteria derivation, acceptable
subchronic and chronic endpoints are those
which affect organismal growth or viability,
or reproductive or developmental success or
any other endpoint which is, or is directly
related to, parameters that influence
population dynamics. .
Chronic effect An adverse effect, measured
by assessing an acceptable endpoint,
resulting from continual exposure over
several generations, or at least over a
significant part of the test species projected
life span or life stage.
Lowest-observed-adverse-effect-level
(LOAEL). The lowest tested dose or
concentration of a substance which resulted
in an observed adverse effect in exposed test
organisms when all higher doses or
concentrations resulted in the same o:t more
severe effects.
No-observed-qdverse-effect-level (NOAEL).
The highest tested.dose or concentration of
a substance which did not result in an
observed adverse effect in exposed test.,;
.Organisms. :
, Subchronic effect. An adyerse.effecf,
measured by assessing an acceptable " .. - .
endpoint, resulting from continual exposure
for a period of time less than that deemed
necessary for a chronic test :
B. Minimum Toxieity Database for The I
Criteria Development
•: A NOAEL or LOAEL value is required for
. criterion calculation. To derive a Tier I
criterion for wildlife, the minimum toxieity
database required must provide^enough data ,
to generate a subchronic or chronic dose-
response curve for any given substanca for
boUi mammalian and avian species.
• In reviewing the toxieity data available
which meets the mhiiiniim data requirements
for each taxonomic class, the following order
of preference shall be applied to select the
appropriate NOAEL or LQAEL tp be used for
! calculation of individual wildlifayarues.
•• Data from peer-reviewed field studies of
wildlife species takes precedence oveit other
types of studies. An acceptable field study
. must be of subphrpniic or chronic dotation,
provide a defensible, chemical-specific dose-
response curve in which cause and effect are
clearly established, and assess acceptable
endpoints as defined in this document. When
acceptable wildlife field studies are not
available, the needed toxieity information
may come from peer-reviewed laboratory
studies. When laboratory studies are used,
preference shall be given to laboratory
studies with wildlife species over traditional
laboratory animals to reduce uncertainties in
making interspecies extrapolations.
Whenever possible, all available laboratory
data and field studies shall be reviewed to
corroborate .the final GLWC, to Assess the
reasonableness of'the toxieity,value used,
and to assess the appropriateness of any
uncertainty factors which are applied. •
" • When laboratory data are used, the
following requirements must be met:
1. The mammalian data must come from at
least one well-conducted study of 90 days or
greater designed to observe subchronic or
chronic effects as defined in this document.
2. The. avian data must come from at least
one well-conducted study of 28 days or
greater designed to observe subchronic or
chronic effects as defined in this document.
In reviewing the studies from which a
NOAEL is derived for use hi calculating a •
wildlife value, studies involving exposure
routes other than oral may be considered
only when an equivalent oral daily dose can
be estimated and technically justified. This is
because the mechanism of toxieity and/or
issues of dosimetry (e.g. delivered dose to
target organs, extent of xenobiotic ' - - .
metabolism, etc.) for other routes of exposure
(e.g., dermal or inhalation) may differ; and
the criteria and value calculations are based
on an oral route of exposure.
In assessing the studies which meet the
minimum data requirements, preference
should be given to studies which assess
effects oh developmental or reproductive
'endpoints because, in general, these are more
important endpoints in ensuring that a
population's productivity is maintained.
C Minimum Toxieity Database for Tier n
Wildlife Value Development
For those substances for which Tier I .
criteria cannot be derived, all data from avian
and mammalian species may be considered
in the development of Tier n values. To
derive a Tier II value for wildlife, the
minimum toxieity database required must
provide enough data to generate a subchronic
or chronic dose-response curve for any given.
substance for either a mammalian or avian
species. Subchronic or chronic toxieity data
shall be used to derive NOAELs for Tier II
values. When laboratory data for avian
species is used to calculate a Tier II wildlife
value, it must meet the same requirements
presented above for Tier I criteria derivation.
When laboratory data for mammals is used tp
calculate a Tier n wildlife value, a 28-day
subchronic study which assessed acceptable '
endpoints may be used in addition to studies
which meet the requirements presented
above for Tier I criteria derivation. Relevant
LD50 or eight-day LC50 values from avian
and mammalian studies may be used in
support of subchronic and chronic toxieity
data; however, a Tier n value shall not be
calculated solely on the basis of LD50 or
eight-day LC50 data.
D. Selection of NOAEL or LOAEL Data
. In selecting data to be used in the
derivation of wildlife values, the nature of
the observed endpoints will be the primary
selection criterion. All data not part of the
selected subset may be used to assess the
reasonableness of the toxieity value and the
appropriateness of any uncertainty factor
which is applied.
1. If more than one NOAEL is available :•
within a taxonomic class, based on different
endpoints of toxieity, that NOAEL which
likely best reflects potentialimpacts to
wildlife populations throughi resultant
changes in mortality and/or fecundity rates :
shall be used for the calculation of wildlife
. values. , • -...;. -••' •
2. If more than one NOAEL is available
within a taxonomic class based on the same
endpoint of toxieity, the NOAEL from the
most sensitive species is used.
3. If more than one NOAEL based on the
same endpoint of toxieity is Available for a
given species, the NOAEL for that species
shall be. calculated usmg the geometric mean
of those NOAELs.
E, Determination of the NOAEL in Proper
Units •;..;• : : ,
In those cases in which a NOAEL is ,
available in units other than mg/kg-d, the
following procedures shall be used to convert
the .NOAEL to appropriate units prior to
calculating a wildlife value.
If the NOAEL is given in milligrams of
toxicant per liter of water consumed by the
test animals (mg/L), the NOAEL shall be •
multiplied by the daily average volume of ,
water consumed by the test animals in liters
per day (L/d) and divided by the average
weight of the test animals in kilograms (kg).
If the NOAEL is given in milligrams of
toxicant per kilogram of food consumed by ^
the test animals (mg/kg), the NOAEL shall be
multiplied by the average amount of food in
kilograms consumed daily by the test animals
(kg/d) and divided by the average weight of
the test animals in .kilograms (kg).
F. Drinking and Feeding Rates .
When drinking and feeding rates and body
weight are needed to express the NOAEL in
mg/kg-d, they should be obtained from the
study from which the NOAEL was derived.
If not already determined, body weight, and
drinking and feeding rates are to be -
converted to a wet weight basis. •
lithe study does not provide the needed... •
values, they shall be determined from
appropriate data tables-Air the particular
study species. For studies done with
domestic laboratory animals, the following
reference should be consulted:' Registry of
Toxic Effects of Chemical Substances
(National Institute for OccupationaLSafety
and Health, the latest edition, Cincinnati, '
OH.). When insufficient data exist for other
mammaUan or avian species, the allometric ;
.equations from Calder and BraUn (1983) and
Nagy (1987) which are presented below phall
be applied to approximate the needed
feeding or drinking rates. '
For mammalian species the allometric
equations are;
i. FA = 0.0687 x (WtA)°-82
Where: , ""..
FA=Feeding rate of mammalian
species in kilograms per day (kg/d) ,
dry weight.
WtA=Average weight in kilograms (kg)
, •; of the test animals. ,':;
2. \\k = 0.099 x
Where: ;: .'.". :: _./{: :.,'•.• •".,• ; '•''-•'• .-" ••
Wx=I3rinking rate of mammalian •
specdes in liters per day (L/d).
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231030 Federal Register / Vol. 58, No. 72 I Friday, April 16, 1993 /• Proposed Rules
WtA=«Averag3 weight in kilograms (kg)
of the test animals.
For avian species the allometric
equations are:
3. FA= 0,0582 x(WtA)°'65
Where:
FAs=Feoding rate of avian species in
kilograms per day (kg/d) dry
weight.
WU^Average weight in kilograms (kg)
of the test animals.
4, WA= 0.059 x(WtA)°'67
Where:
WA=Drinking rate of avian species in
liters per day (L/d).
WtA»Averag9 weight in kilograms (kg)
of the test animals.
G. LOAEL to NOAH. Extrapolations
la those cases in -which a NOAEL is
unavailable and a LOAEL is available, the
LOAHL may be adjusted to estimate the
NOAEL. Typically, the LOAEL is divided by
an uncertainty factor to estimate a NOAEL for
ute in deriving wildlife values. The value of
the uncertainty factor is typically within the
range of 1.0 and 10, depending on the dose-
rosponta curve. Additional references which
support this concept and are useful in
choosing an appropriate LOAEL to NOAEL
unwUinty factor are provided in the
Technical Support Document for Wildlife
Criteria (U.S, EPA, 1993a). Assistance in
choosing an appropriate LOAEL to NOAEL
uncertainty factor is also provided in
appendix A to the Great Lakes Water Quality
Initiative (GLWQI) Technical Support
Document for Human Health Criteria and
Values (U.S. EPA, 1993b).
H. Subchronic to Chronic Extrapolations
In certain Instances where only subchronic
data ate available, the NOAEL may be
dMWtod by an uncertainty factor to
extrapolate from tubchronlc to chronic
levels. Typically the value of the uncertainty
fecloc Is within the range of 1.0 and 10. This
factor may he usad when assessing highly
biotccumuktive substances where
tojdcoldnrtlc considerations suggest that a
hkwscay of limited length underestimates
chronic hazard. Assistance in choosing an
appropriate subchronic to chronic
uncertainty factor is provided in appendix A
to the GLWQJ Technical Support Document
tor Human Health Criteria and Values (U.S.
EPA. 1993b),
I. Spedts Sensitivity Factor
The selection of the species sensitivity
factor (SSF) shall be based on the available
lexicological data and on available data
concerning the physicochemical,
toxlcofclnatic and toxicodynamic properties
of the substance in question and the amount
and quality of available data. This value is an
uncertainty factor that is intended to account
for differences in lexicological sensitivity
among species. Guidance for choosing the
SSF is provided in the Technical Support
Document for Wildlife Criteria (U.S. EPA,.
1993a).Tfle discussion of an interspecies
uncertainty factor located in appendix A to
the GLWQI Technical Support Document for
Human Health Criteria and Values (U.S. EPA/
1993b) may also be useful in determining the
appropriate value for a SSF.
For the derivation of Tier I criteria, a SSF
within the range of 0.01 to 1.0 may be
applied. If a SSF outside this range is used,
it must be based on sound scientific and
technical reasons and must be accompanied
by a written justification presenting this
reasoning. This justification shall be
provided to EPA as part of the State's or
Tribe's submission as required under § 132.5.
Use of a SSF outside this range is prohibited
unless approved by EPA based on its
consideration of the justification provided.
F.orTier I wildlife criteria, the SSF shall ba
used ftjr extrapolating toxicity data across
species within a taxonomic class. The Tier I
SSF is not intended for interclass
extrapolations because of the poorly defined'.
comparative toxicokinetic and
toxicodynamic parameters between mammals
and birds. However, an interclass
extrapolation employing a SSF may be used
for a given chemical if it can be supported
by a validated biologically-based dose-
response model or by an analysis of
interclass toxicologies! data, considerate of
acceptable endpoints, for a chemical analog
that acts under the same mode of toxic
action.
For the derivation of Tier H wildlife values,
a SSF may not be greater than 1.0 but may
be lower than 0.01 without requiring a
written justification..For Tier H wildlife
values, the SSF may be used to extrapolate .
toxicity data across the two taxonomic
classes. ,
IV. Parameters of the Exposure Component of
the Wildlife Criteria Methodology
A. Drinking and Feeding Rates of
Representative Species or Species Requiring
Greater Protection
The body weights (WU), feeding rates (FA),
and drinking rates |WA) for each of the five
representative species are presented in Table
D-2 of this appendix. Trophic level dietary
composition for these species are also
presented in Table D-2 of this appendix for
use in selecting the correct bioaccumulation
factor for use in the WV equation.
If the feeding rate (FA) or drinking rate
(WA) for the species requiring greater
protection are not known, they can be
estimated using tho allometric equations
presented above in section III.F of this
appendix.
B. Bioaccumulation Factors
The Methodology for Development of
Bioaccumulation Factors is presented hi
appendix B to part 132. This Guidance
document specifies that, in general, trophic
level three or four BAFs are to be used in the
derivation of wildlife values, depending on
the species identified for protection. "Trophic
level three and four BAFs are used because
these are the-trophic levels at which the
representative species identified for
protection feed. Options to use plant and or
other trophic level BAFs are permitted based
on the identification of a species requiring
greater protection which may feed, in part or
whole, at other trophic levels.
V. References
Barnes D. G. and M. Dourson. 1988.
Reference Dose (RfD): Description and Use in
Health Risk Assessments. Regul. Toxicol.
PharmacoL 8:471-486. Academic Press, Inc.
1250 6th Avenue;San Diego, CA 92101-
4312.
Calder ffl, W, A. and E, J. Braun. 1983.
Scaling of Osmotic Regulation in Mammals
and Birds. American Journal of Physiology.
244:601-606. Williams and Wilkins, 1316
East 16th Street, Brooklyn, NY 11230-6003,
Nagy, K. A. 1987. Field Metabolic Rate and
Food Requirement Sealing in Mammals and
Birds. Ecological Monographs. 57(2):111-
128. Ecological Society of America, Arizona
State University, Tempo, AZ 85287-0001.
• National Academy of Sciences. 1977.
Chemical Contaminants: Safety and Risk
Assessment, pp. 19-62 in Drinking Water
and Health, Volume 1. National Academy
Press, 2101 Constitution Avenue, NW.,
Washington, DC 20418.
National Academy of Sciences. 1980.
Problems of Risk Estimation, pp. 25-«5 in
Drinking Water and Health, Volume 3.
National Academy Press, 2101 Constitution
Avenue, NW., Washington, DC 20418.
National Institute for Occupational Safety
and Health. Latest edition. Registry of Toxic
Effects of Chemical Substances (available
only on microfiche or as an electronic
database). Division of Standards
Development and Technology Transfer, 4676
Columbia Parkway, Cincinnati, OH 45226.
U.S. EPA. 1980. Appendix C. Guidelines
and Methodology Used in the Preparation of'
Health Effect Assessment Chapters pf the
Consent Decree Water Criteria Documents.
'pp. 79347-79357 in Water Quality Criteria
Documents; Availability. Available from U.S,
Environmental Protection Agency, Office of
Water Resource Center (WH-550A), 401 M
St.. SW., Washington, DC 20460.
U.S. EPA. 1985. Section V.C. Evaluation .of
Health Effects and Determination of RMCLs
pp. 46944-46950 in National Primary
.Drinking Water Regulations; Synthetic
Organic Chemicals; Inorganic Chemicals and
Microorganisms. Available from U.S,
Environmental Protection Agency, Office of
Water Resource Center (WH-550A), 401 M
St., SW,, Washington, DC 20460.
U.S. EPA. 1993a. Great Lakes Water.
Quality Initiative Technical Support
Document for Wildlife Criteria. Available .
from U.S. Environmental Protection Agency,
Office of Water Resource Center IWH-55DA)
401 M St. SW,, Washington, DC 20460.
U.S. EPA. 1993b. Great Lakes Water
Quality Criteria Initiative Appendix Ai
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' " Federal Register /Vol.'58. No. 72 /'Friday/April 16, 1993 / Proposed. Rules 21031
Uncertainty Factors, in Great Lakes Water
Quality Criteria Initiative Technical Support
Document for Human Health Criteria and
Values.^ NTIS #PB93-15468.ERIC: 3940.
Tables to Appendix D to Part 132
TABLE D-i .--TIER I GREAT LAKES WILDLIFE CRITERIA
,-. . ; •• ' '; '• •• .Substance - • - ,' ' ' '--. ' ;
• - -• -''--• ..-..-«• • •
DDT & Metabolites .................;.. '. .: „
Mercury :........ . .
PCBs (total) :; ;... ;........................; ; .
2,3,7,8-TCDD .. ;
Criterion
0 87 DO/L
180 PQ/L - •
17pg/L
0.0096 pg/L
TABLE D-2.—EXPOSURE PARAMETERS FOR THE FIVE REPRESENTATIVE §PECIES IDENTIFIED: FOR PROTECTION
, - •'.' Species
Mink .....>....,..„ .......:....... .....;.; •
Otter.... ......
Kingfisher :... „....,-
Osprey ........;. ;.. .. .....
Eagle ., ................I
Body Wt.
(WtA)
(Kg)
10
80
015
15
4.5 :
Ingestion
rate f A)
(Kg)d)
0"15
09
0 075
03
0.5
Drinking
rate (WA)
(L/d)
0099
064
0017
0 077
0.16
Trophic level
of wildlife
food source
3'
3
' 4
- "• . ', 4
Percent diet
at each
trophic level
10fl
50
50
inn
ion
100
Appendix E to Part 132—Great Lakes
Water Quality Initiative
Antidegradation Policy ' .
' I. Antidegradation Standard
This antidegradation standard shall be
applicable to any source, point orrionpoint,
of pollutants to surface waters of the Great
: Lakes System. Pursuant to this standard:
, A. Existing instream water uses, as defined
pursuant to 40 CFR part 131, and the level
of water quality necessary to protect existing
' uses shall be maintained and protected.
Where designated uses of the water body are
impaired, there shall be no lowering of the
water quality with respect to the pollutant or
pollutants which are causing the impairment;
' B, Where, for any parameter, the water
quality exceeds that level necessary to ,
support the propagation offish, shellfish, and
wildlife and recreation hi and on the waters,
that water shall be considered high quality
for that parameter and that quality shall be
maintained and protected unless the State •
finds, after full satisfaction of
intergovernmental coordination and public
participation provisions of the State's
continuing planning process, that allowing
ipwer water quality is necessary to
accommodate important economic or social
. development in the area in which the waters
are located. In allowing such degradation, the
State shall assure water quality adequate to
protect existing uses fully. Further, the State
shall assure that there shall be achieved the
highest statutory and regulatory requirements
for all new and existing point sources and all
cost effective and reasonable best
management practices for nonpoint source
controls. The State shall utilize the
Antidegradation Implementation Procedures
of section II of this appendix, the
Antidegradation Demonstration provisions of
section ID of this appendix, and the .
Antidegradation Decision provisions of
section IV of this appendix in determining if .
the significant lowering'of water quality shall
he allowed; :
C. Where high quality waters constitute an
outstanding National resource, such as
waters of National and State parks and
wildlife refuges and waters of exceptional
recreational of ecological significance, that,.
water quality shall be maintained and ., :
protected; and
D. In those cases where the potential ,
lowering of water quality is associated with
a thermal discharge, the decision to allow
such degradation shall be consistent with
section 316 of the Clean Water Act
JI. Antidegradation Implementation.
Procedures : • • .'
A. Definitions—Bioaccumulative chemical
of concern. A bioaccumulative chemical of •
concern is: Any chemical which, upon
entering the surface waters, by itself or as its
. transformation product, bioaccumulates in
aquatic organisms by a factor greater than
1000. BCCs include all of the pollutants
.identified as BCCs in Tab.le 6 of part 132."
De minimis. The lowering of water quality
iby a pollutant may be considered de minimis
if it satisfies all of the following criteria for
the pollutant under consideration, arid such
a determination is consistent with applicable
requirements and limitations in appendix F
to 40 CFR 132 (implementation procedures),
including appropriate margin of safety
allocations:
—The lowering of water quality does not
involve a bioaccumulative chemical of
concern; .* ,
—The lowering of water quality uses less
than 10 percent of the unused assimilative
capacity; and
—For pollutants included on Table 5 of part
132, at least 10 percent of the total
assimilative capacity remains unused after .
• the lowering of water quality; '
where; , ;
—Unless impracticable, the total assimilative
capacity is determined as the product of
the applicable water quality criterion times
the critical, low flow, or designated mixing
volume in the.case of lakes, for the water
, body in the area where the water quality
: is proposed to be lowered, expressed as a
> mass loading rate. The unused assimilative
capacity is that amount of the total
- assimilative capacity not utilized by point
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21032
Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
source and nonpoint source discharges.
Tho unused assimilative capacity is
wtabHsfaed at the time the request to lower
water quality is considered,
H&J» quality waters. High quality waters
are those that satisfy the criteria spcified in
soction 1.B of this appendix regarding the
quality of tho water.
Lake Superior Basin—Outstanding
National Resource Wafers. Lake Superior
Basic—Outstanding National Resource
Waters shall be those designated as such by
tho Stale consistent with the September 1991
Bi-Ntllonil Program to Restore and Protect
the Lake Superior Basin. The purpose of such
desSgnettons shall be to prohibit new or
increased discharges of Lake Superior
bio-accumulative substances of immediate
ccr.com from point sources in these areas.
Lake Supurtarbioaccumulalive substances
offamsdiata concern, A list of substances
identified Sa tho September 1891 Bi-National
Program to Restore and Protect the Lake
SuptHor Batin. They include: 2,3,7,8-TCDD;
octachloioftyrenej hexachlorobonzene;
chlocdtae; DDT, DDE, and other metabolites;
toxupfaese; PCBs; and mercury. Other
chemicals may be added to the list following
tha State's assessments of environmental
effects and impacts and after public review
mad comment,
Qr.titanding National flesouree Waters.
Outstanding National Resource Waters
(GNRW*) shall be those designated as such
by fta States, The State ONRW designation
shall describe the quality of such waters to
stttva M Us« benchmark of the water quality
that thill be maintained and protected.
Categories of watars which are eligible for
designation include but are not limited to the
following five categories, which are waters
recognized as;
—Important because of protection through
official action, such as Federal or State law.
Presidential or Secretarial action,
mtanwlionel treaty, or Interstate compact;
—•Having exceptional recreational
significance;
—Having exceptional ecological significance;
—Htving other special environmental,
recreation:.!, or ecological attributes: or
—Waters whose designation as Outstanding
National Resource Waters is reasonably
necessity for the protection of waters
Identified in above.
Pollutant, The term pollutant is as defined
to fecttoa 502 of tHe Clean Water Act and
includes toxic, conventional and
noccoQventional pollutants, and
bloaccumula'.ivo chemicals of concern as
they are defined in this section.
Significant lowering of water quality. A
significant lowering of water quality occurs
when any of the following conditions exist:
—There is an Increase in the rate of mass
loading. In excess of that defined by the
existing effluent quality controls
established pursuant to section II. D. 1. of
this appendix, of any bioaccumulative
chemical of concern to the surface water
from an action by the permitted at aa
existing, expanding or new point source;
-That* is art increase in the rate of mass
loading, in excess of that defined by the
existing effluent quality controls
established pursuant to section n. D. 1. of
this appendix, of any bioaccumulative
chemical of concern to the surface water
• from an action by the regulated entity at an
existing, expanding or new nonpoint
source, where existing independent
regulatory authority requires compliance
with water quality standards;
—There is an increase, other than a de
minimis increase, in the permit limitations
governing the rate of mass loading of any
pollutant that is not a bioaccumulative
chemical of concern to the surface water at
an existing, expanding or new point
source, unless the ambient concentration of
the pollutant in the affected water body,
outside of a designated point source
mixing zone, where applicable, will not
increase. The Director may also take into
consideration potential impacts on
sediments and biota;
—There is aa increase in the permit
limitations governing the rate of mass
loading of any pollutant that is not a
bioaccumulative chemical of concern from
a nonpoint source, where existing
independent regulatory authority requires
compliance with water quality standards,
where such permit limitations are those
authorized by the governing nonpoint
source program, unless the ambient '
concentration of the pollutant in the
affected water body, outside of a
designated mixing zone, where applicable,
will not increase. The Director may also
take into consideration potential impacts
on sediments and biota; or
—For any action, where such action is
determined by the Director, on a case-by-
case basis, to be significant
B. For all waters, the Director shall ensure
that the level of water quality necessary to
protect existing uses is maintained. In order
to achieve this requirement, and consistent
with 40 CFR 131.10, water quality standards
use designations must include all existing
uses. Controls shall be established as
necessary on point End nonpoint sources of
pollutants to ensure that the criteria
applicable to the designated use are achieved
ia the water and that any designated use of
a downstream water is protected Where
water quality does not support the designated
uses of a water body or ambient pollutant
concentrations exceed water quality criteria
applicable to that water body, the Director
shall allow no lowering of water quality for
the pollutant or pollutants preventing the
attainment of such uses or exceeding such
criteria.
C. For Outstanding National Resource
Waters:
1. The Director shall ensure, through tie
application of appropriate controls on
pollutant sources, that water quality is
maintained and protected.
2. Exception. A short-term, temporary
(weeks or months) lowering of water quality
may be permitted by the Director.
D. For high quality waters, the Director
shall ensure that no significant lowering of
water quality occurs except as the action
resulting in the significant lowering of water
quality satisfies the conditions of section ill
of this appendix regarding completion of an ,
antidegradation demonstration and the
information thus provided is determined by
the Director pursuant to section IV of this
appendix to adequately support the
significant lowering of water quality.
1. To prevent the significant lowering of
water quality that would result from any
increased rate of mass loading of a
bioaccumulative chemical of concern from
ajiy source, the Director shall establish
conditions in the control document
applicable to the pollutant source that
restricts, unless prior approval for an
increase is received from the Director, the
rate of mass loading of such bioaccumulativi,
chemical of concern to the baseline level
established, considering historical rates of
discharge, at the time of issuance of the
control document. In establishing the
existing effluent quality level, all data
collected over the term of the previous
control document that are representative of
(a) the typical operation of the pollutant
source at the time of permit issuance and (b)
bioaccumulative chemical of concern mass
loading rates at the time of permit reissuance,
should be utilized to define the existing
effluent quality. The Director may account
for recent temporary changes in effluent
quality that are not, representative of mass
loading rates generally experienced and
expected to resume in the future.
For point source dischargers, such control
requirements shall be specified in the
discharger's National Pollutant Discharge
Elimination System (NPDES) permit upon
reissuance and may include, but are not
limited to, effluent limitations, notification
requirements, or discharge prohibitions,
provided that the control requirements
utilized prevent any increase in the rate of
bioaccumulative chemical of concern mass
loading. A subsequent increase in the rate of
mass loading may be authorized by the -
Director provided such increase has been
supported by a satisfactory antidegradation
demonstration pursuant to section III of this
appendix, and provided the control
document is modified to specify the newly
approved rate of mass loading. Control
documents shall also contain a condition
which prohibits the entity responsible for the
pollutant loading from undertaking any •
deliberate action the result of which would
be an increase in the rate of mass loading of
any bioaccumulative chemical of concern,
unless an antidegradation demonstration is
provided to the Director and prior approval
is obtained from the Director.
2. To prevent the significant lowering of
water quality that may result from a change
in control requirements, such as effluent
limitations in an NPDES permit, except as
such change is determined by the Director to
result in a de minimis lowering of water
quality based on the criteria in section II.A
of this appendix, no such change shall be
allowed unless and until an antidegradation
demonstration pursuant to section III of this
appendix is provided by the entity and
approved by the Director! In addition to the
above requirements, no limitation in an
NPDES permit may be made less stringent in
a subsequently issued permit except as in
compliance with40 CFR 122.44(1),
3. Fact Sheets prepared pursuant to 40 GFR
124.8 and 124.56 shall indicate when
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Federal Register / VoL 58, No. 72 / Friday, April 16, 1993 / Frooosed Rules
21033
conditions developed under sections ILD. 1 or
CUD. 2 of this appendix are included in a
permit.
E. Special Provisions for Lake Superior.
The following conditions apply in addition
to those specified in sections n.B through ILD
of this appendix for waters of Lake Superior
so designated.
1. A State may designate certain specified
areas of the Lake Superior Basin as Lake
Superior Basin— Outstanding National
Resource Waters for the purpose of
prohibiting the new or increased discharge of
Lake Superior bioaccumulative substances of
immediate concern from point sources in :
these areas.
2. States may designate all watersof the
Lake Superior Basin as Outstanding
International Resource Waters for jthe
purpose of restricting the increased discharge
of Lake Superior bioacaimulative substances
of immediate concern from point sources
consistent with the requirements of sections
III.C and IV. A.3 of this appendix.
F. Exemptions. Except as the Director may
determine on a case-by-flase basis that the
application of these procedures is required to
adequately protect water quality, or as the
. affected water body is an outstanding
National resource water as defined in section
H. A of this appendix, the procedures in this
part do not apply to:
1, Short-term, temporary {weeks' or
months) lowering of water quality;
2. Bypasses that are not prohibited at 40
. CFR 122.41(m); and ,
3. Response actions pursuant to the
Comprehensive Environmental Response,
, Compensation and Liability Act, as amended,
or similar Federal or State authorities,
undertaken to alleviate a release into tha
environment of hazardous substances,
pollutants or contaminants which may pose
an imminent and substantial danger to public
health or welfare. . .
III. Antidegmddtion Demonstration
Any entity seeking to significantly lower
water quality ia a high quality water or create
a new or increased discharge of Lake
• Superior bioaccumulativa substances of
immediate concern in a Lake Superior
Outstanding International Resource Water
must first, as required by sections H.D or
II.E.2 of this appendixt Submit an '
antidegradation demonstration for
consideration by the Director The
antidegradation demonstration shall identify:
A. Pollution Prevention Alternatives
Analysis. Identify any prudent and feasible
pollution prevention alternatives and
techniques that are available to the entity *Nt
would eliminate or significantly reduce the
extent of the lowering of water quality.
1. Alternatives that must be evaluated
include:- • . '. ' • - . •
a. Substitution of bioaccumulative
chemicals of concern with non- , -
bioaccumulative and/or non-toxic .:• ,
.substances; . •
, b. Application of water conservation ,.
methods; , . . ,. , : ' .
c. Waste source reductions within process .
,
-> d-Recycle/reuse of waste by-products,
either liquid, solid, or gaseous; and .
e, Manufacturing process operational
changes,
2. Should such alternatives eliminate the
need to significantly lower water quality, the
entity shall not be required to provide the
infoniiatibn specified in sections HLB and
III.D of this appendix. , , :
B, Alternative or Enhanced Treatment,
Identify alternative or enhanced treatment
techniques that are available to the entity that
would eliminate the significant lowering of
water quality. The evaluation shall define the
total capital and operation costs associated
with such alternative or enhanced treatment
techniques as well as the total capital and
. operation costs associated with pollution
control facilities necessary to achieve Federal
effluent guidelines-based, water quality-
based effluent limitations and other
applicable State or Federal s'tandards, and '•
calculate the ratio of the former costs to the
latter costs. If the ratio is less than or equal
to 1.1, the entity shall not be required to
provide information specified in section ffl.D
of this appendix. .-..--•
C. Lake Superior. If the States designate the
waters .of Lake Superior as Outstanding
International Resource Waters pursuant to
section II.E.2 of this appendix, then any
entity proposing a new or increased !
discharge of any Lake Superior
bioaceunnilative substance of immediate
concern to the Lake Superior Basin shall
identify the best technology in process and
treatment to eliminate or reduce the extent of
the significant lowering of water quality. In •
this case, the requirements ia section HLB of
this appendix do not apply. s
D. Important Social or Economic
Development. Identify the social or economic
developments to the area in which'the waters
are located that will be foregoae.if the
significant lowering of water quality is not
allowed. Developments eonsidered-ia'ust fall
into one of the following categories:
1. Increase in the number of jobs;
2, Increase in personal income or wages;
3, Reduction in the unemployment rate or
other social service expenses;
.4. Increase hi tax revenues; or . •
5. Provision of necessary social.services?
E. Special Provision for Remedial Actions,
Entities proposing remedial actions pursuant
to the Comprehensive Environmental
Response, Compensation and Liability Act,
as amended, corrective actions pursuant to
the Resource Conservation and Recovery Act,
as amended, or similar actions pursuant to
other Federal or State environmental statutes
may submit information to the Director that
demonstrates that the action utilizes the most
cost effective pollution prevention and
treatment techniques available, and
minimizes the necessary lowering of water
quality, hi lieu of the information required by
sections ffl.B through ELD of this appendix.
IV. Antidegradation Decision
A. Once the Director determines that the
information provided by the entity pursuant
to sections 31I.A through HLDof.this
appendix is administratively complete the
Director shall-use the informattont as follows,
to determine the extent to which water
quality may be lowered by the entity.
Remedial actions covered-by section HLE of
this appendix shall be required to implement
the most cost-effective pollution prevention
and treatment techniques available. All other
actions shall be required to implement
controls as identified pursuant to sections
IV.A.1 through IV.A.5 of this appendix, In no
event may the decision, reached under this
section allow the water quality to be lowered
below the minimum level required to fully
support existing uses and designated uses.
1. If the information provided pursuant to
section IIL A of this appendix demonstrates
that there exist prudent and feasible •
pollution prevention alternatives which
significantly reduce the lowering of water
quality, the Director shall require
•implementation of such measures as part of
the authorization to significantly lower water
quality or deny the significant lowering of
water quality.
2. If the cost ratio defined pursuant to
section ffi.B of this appendix is less than or
equal to 1.1, then the Director shall deny the
request to significantly lower water quality.
3. If States designate the waters of .Lake
Superior as Outstanding International
Resource Waters pursuant to section ILE.2 of
this appendix, any entity requesting to lower
water quality in the Lake Superior Basin as
a result of the new or increased discharge of
aay Lake Superior bioaccumulative:
substance of immediate concern shall be
required to install and utilize the best
technology in process and treatment as
identified by the Director.
4, Should the requirements of section
IV.A.1, IV.A.2, or IV. A.3 of this appendix not
preclude the significant lowering o~f water
quality, the Director shall consider the social
or economic developments associated with
the action identified pursuant to section TTTTI
of this appendix and the environmental
effects of the significant lowering of water
quality. Based on this analysis, the Director
shall determine if the significant lowering of
water quality should be proposed to be
allowed.
5. The Director may choose to defer the
review in section IV.A.4 of this appendix
until after the public is provided the
•• opportunity to comment, siibject to the
conditions of section IV.B.2 of this appendix
B. The tentative decision of the Director
regarding the'extent to which water quality
may be significantly lowered shall be subject
to the public participation requirements of 40
CFR part 25. To the extentthat the tentative
decision is embodied in the conditions of an •
NPDES permit, the public participation
requirements may be satisfied by the public
notice of the draft permit and fact sheet •
which discusses the antidegradation
demonstration and decision regarding the
significant lowering of water quality.
1. If the Director's decision is based on the
analysis in section IV.A.4 of this Appendix,
then the public notice of the decision shall.
define the extent of significant lowering of
water quality tentatively determined by the
Director to be allowable, and the factors
coaslderedln reaching that decision. •
.2. If the DLrector chooses to defer the
review as provided in section IY.A.5 of this
appendix, then the Director shall tentatively
determine that the significant lowering of
water quality is not allowable. The public
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"K Li, I1:,,,,111. "I1,,!,,1
notka shall state that a decision that is based
on • review of the social or economic
developments and environmental effects
associated •with the action, has been deferred,
ponding review of the comments received
from the public, and that the tentative
decision may subsequently be revised.
Appendix F to Part 132—Great Lakes
Water Quality Initiative
Implementation Procedures
[Note: For casa of reference, sections in this
appendix may be referred to by appending
the section designation lo the procedure
number. For example, section A.l of
procedure 1 may be referred to as procedure
i.A.1 of appendix F.]
Procedure 1: Site-specific Modifications to
Criteria/Values
A. Requirements for Site-specific
Modifications to Criteria/Values. Criteria or
values may be modified on a site-specific
basis !o reflect local environmental
conditions as restricted by the following
provisions, Any such modifications must be:
protective of designated uses and aquatic life,
wikilifa and human health; and submitted to
EPA for approval/disapproval. In addition,
any site-specific modifications that result in
lits stringent criteria must be based on sound
scientific rationale.
I, Aquatic Ufa. Aquatic life criteria or
values may be modified on a site-specific
basis to provide an additional level of
protection, pursuant to authority reserved to
the States and Tribes under Clean Water Act
section 510.
I. Less stringent site-specific modifications
to chronic or acute aquatic life criteria or
values may be developed when:
1. The local water quality parameters such
as pH, hardness, temperature, color, etc.,
alter tho biological availability and/or
toxidty of a pollutant; and/or
ii. The sensitivity of the local aquatic
organisms (i.e., those that would live in the
water absent man-induced pollution) differs
significantly from the species actually tested
in developing tho criteria.
Guidance oa developing site-specific
criteria in these instances is provided in
Chapter 4 of the U.S. EPA Water Quality
Standards Handbook.
b. Lets stringent modifications also may be
developed to tha chronic aquatic life criteria
or values to reflect local physical and
hydrologicsl conditions.
2. Wildlife. Wildlife criteria or values may
be modified on a site-specific basis to
provide an additional level of protection,
pursuant to authority reserved to the States
and Tribes under Clean Water Act section
S10. This may be accomplished through the
u$o of an additional uncertainty or other
documented factor in the equation for the
Wildlife Value.
3, Bioaccumulation. Bicaccumulation
factors may be modified on a site-specific
basis to larger values than derived pursuant
to authority reserved to the States and Tribes
under Clean Water Act section 510.
Bioaccumulation factors shall be modified on
• tito-sptcific basis where reliable data
shows that local bipaccumulation is greater
than the system-wide value.
4. Human Health. Human health, criteria or
values may be modified on a site-specific
basis to provide an additional level of
protection, pursuant to authority reserved to
the States and Tribes under Clean Water Act
section 510. Human health criteria or values
shall be modified on a site-specific basis to
Erovide additional protection appropriate for
ighly exposed subpopulations.
B. Notification Requirements. When a State
proposes a site-specific modification to a
criterion or value as allowed in section A
above, the State shall notify the other Great
Lakes States of such a proposal and, for less
stringent criteria, supply appropriate
justification.
C. References. U.S. EPA. 1983. Water
Quality Standards Handbook. Chapter 4. U.S.
Environmental Protection Agency, Office of
Water Resource Center (RG-4100), 401 M
Street, SW., Washington, DC 20960.
Procedure 2: Variances from Water Quality '
Standards for Point Sources
The Great Lakes States or Tribes may adopt
water quality standards (WQS) variance
procedures and may grant WQS variances for
point sources in compliance with such
procedures. Any adopted variance
procedures shall be at least as stringent as the
provisions in this Guidance.
A. Applicability. The Great Lakes States or
Tribes may grant a variance to a water quality
standard (WQS) which is the basis of a water
quality-based effluent limitation included in
an NPDES permit. A WQS variance applies
only to the permittee requesting the .variance
and only to the pollutant or pollutants
specified in the variance. A variance does not
affect, or require the Great Lakes States or '
Tribes to modify, the corresponding WQS for
the water body as a whole.
This provision shall not apply to new
dischargers or recommencing dischargers.
B. Maximum Timeframefor Variances. A
WQS variance shall not exceed three years.
Upon expiration of a variance, the WQS of
the water body will have full force and effect
on the permittee. '
C. Conditions to Grant a Variance. A
variance may be granted if the permittee
demonstrates to the Great Lakes State or
Tribe that attaining the WQS is not feasible
because:
1. Naturally occurring pollutant
concentrations prevent the attainment of the
WQS;
2. Natural, ephemeral, intermittent or low
flow conditions or water levels prevent the
attainment of the WQS, unless these
conditions may be compensated for by the
discharge of sufficient volume of effluent
discharges without violating State or Tribal
water conservation requirements to enable
WQS to be met;
3. Human-caused conditions or sources of
pollution prevent the attainment of the WQS
and cannot be remedied or would cause more
environmental damage to correct than to
leave in place;
4. Dams, diversions or other types of
hydrologic modifications preclude the
attainment of the WQS, and it is not feasible
to restore the water body to its original
condition or to operate such modification in
a way that would result in the attainment of
the WQS; ;
5. Physical conditions.related to the
natural features of the water body, such as
the lack of a proper substrate cover, flow,
depth, pools, riffles, and the like, unrelated
to water quality, preclude attainment of
WQS; or .
6. Controls more stringent than those
required by sections 301(b) and 3Q6 of the
Clean Wa'er Act would result in substantial
and widespread economic and social impact,
provided that the permittee also:
demonstrates that the variance requested
conforms to the requirements of the State or
Tribe's antidegradation procedures; and
demonstrates the extent of any increased risk
to human health and the environment
associated with compliance with the variance
compared with compliance with WQS absent
the variance, and the State or Tribe
concludes that any such increased risk is
consistent with the protection of the public
health, safety and welfare. .
A WQS variance may not be granted if .
standards will be attained by implementing
effluent limits required under sections 301(b)
and 306 of the Clean Water Act and by the
permittee implementing cost-effective and
reasonable best management practices for '
nonpoint source control.
D. Timeframe to Submit Application. The
permittee shall submit an application for a
variance no later than 60 days after the
regulatory authority reissues or modifies the
permit. The application shall include:
1. All relevant information demonstrating
that attaining the WQS is not feasible based
on one or more of the conditions in sections
C.1 through C.6 of this procedure; and
2. A demonstration of compliance with the
general conditions in section C of this
procedure.
E. Public Notice of Preliminary Decision.
Upon receipt of a complete application for a
variance, and upon making a preliminary
decision regarding the variance, the Great
Lakes State or Tribe shall issue a public
notice of the request and preliminary
decision for public comment pursuant to the
regulatory authority's Administrative
Procedure Act and shall notify the other
Great Lakes States and Tribes of the
preliminary decision. . •
F. Final Decision on Variance Request. The
Great Lakes State or Tribe shall issue a final
decision on the variance request within 90"
days of the expiration of the public comment
period as required in section E of this
procedure. If all or part of the variance is
approved by the State or Tribe, the decision
shall specify all permit conditions needed to
implement those parts of the variance so'
approved. Such permit conditions shall, at a
minimum, require:
1. Compliance with an initial effluent
limitation which, at the time the variance is
granted, represents the level currently
achievable by the permittee, but no less •
stringent than that achieved under the
previous permit;
2. That reasonable progress be made
toward attaining the water quality standards
for the water body as a whole through
appropriate conditions; and
3. Compliance with the effluent limitation
in effect immediately prior to the granting of
the variance upon the expiration of said
' variance. •
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/ Proposed Eules -
21S35
The Great Lakes State or Tribe stall deny
'•. a requested variance if the permittee fails to
make the demonstration required under
section Cof this procedure. : . v
G. Incorporating State or Tribal Approved
Variance into Permit. Tie NPDES pkmitting
authority shall initiate a penhit modification
- to establish and:incorporate Into the
permittee's NPDES permit all conditions
needed to'implement the variance as
determined in section F,6f this procedure. -
H. Renewal of Variance. A variance may be
renewed, subject So the requirements of
sections A through G of this procedure,
except that renewal application shall bo
submitted no later thafi the required
• submission of a permit application !br a
• NPDES permit, or 60 .days prior to tlie
expiration of the variance, whichevsir occurs
. earliest As part of any renewal application,
the permittee shall again have the burden of
. demonstrating that attaining WQS is not
feasible based on the requirements of section
C of this procedure. The permittee's,,
application shall also contain information
concerning its compliance with the
conditions incorporated into 'its penult as
part of the variance pursuant to section G of
this procedure. A variance shall not be
• renewed if the permittee did not comply with
the conditions of the variance.
I. EPA Approval. Ail variances, including;
•1. Relevant permittee applications
.pursuant to section D of this procedure;
2. Public comments and public hearing
record pursuant to section E of this ,
procedure;
..3. Approvals pursuant to section F.of this
procedure; and
4. NPDES permits issued pursuant to
section G of this procedure shall be , ' "
submitted by the State or Tribe to the
appropriate EPA RegionaLoffice.
Items requiredrby sections 1.1 through 3 of
this procedure shall be submitted by me
Great Lakes State or Tribe within 30 days of
the date of the final variance decision'. Items
required by section 14 of this procedure shall
be submitted in accordance, with me State or
Tribal Memorandum of Agreement with the
Regional Administrator pursuant to 40 CHR
123,24. ' '
EPA shall review the State or Tribe
submittal for compliance with the CWA
pursuant to 40 CFR 123.44, and 40 CFJR
.131.21.
'I- WQSHeMsJons.AllvariaMesmustbe '
appended to the State or Tribal WQS rules.
Procedure 3A: Total Maximum Daily Loads,
Wasteload Allocations and Load Allocations
for Point and Noapoiat Sources; (Option A)
A. General Conditions of Application,The,
following are conditions applicable to' *
establishing total maximum daily loads ., .~
(TMDLs)'for all pollutants and waters within
the Great Lakes System subject to the
exceptions included in 40 CFR 132<4.
1. TMDLs Required. TMDLs shall, at a
minimum, be established for each pollutant
for which it is determined pursuant to
procedure 5 of this appendix that there is a
reasonable potential that a discharge wM
cause or contribute to an.exceedance of water
quality standards, and in advance of issuance
of any new or revised permit for the
dischargo of such pollutant, unless it is
. determined pursuant to these procedures that
a TMDL is not needed. • .
, 2. Load Reductions. TMDLs.shall also be
prepared if the sum of existing point source
aad nonpoint source (including natural
background) loadings exceeds the loading
capacity minus any specified margin of safety
for a substance. A TMDL must ensure
attainment of allnumeric and narrative
criteria and Tier fl values for a given
pollutant TMDLs shall include WLAs&r
point sources aad LAs for nonpoint sources
such that then- sum is not greater than the
loading capacity minus the sum of any
specified MOS and reserve capacity for
future growth.
3. WLA Values. Point sources must be
regulated so as to ensure attainment of all
downstream water quality standards. If
separate TMDLs are prepared for the same
pollutant in different segments of the same
drainage basin, and the separate TMDLs each
include WL As for one or more of the same
point sources, then WQBELS shall be
consistent with the most stringent WLA in an
EPA approved o^EPA established TMDL.
4. Margin of Safety (MOS). Each TMDL
shall include a MOS sufficient to account for
uncertainties in establishing the TMDL and
, describe the manner in which a MOS is
provided. The MOS may be provided by
leaving a portion of the loading capacity
unallocated or by use of protective modeling
assumptions to account for the uncertainties
' in deriving the TMDL. If a separate allocation
of loading capacity is set aside to provide a
MOS, the amount of such allocation shall be
described. If protective modeling
assumptions are relied on to provide a MOS,
the specific assumptions providing the MOS
shall be identified.
5. More Stringent Requirements. States may
exercise authority reserved to them under
section 510 of the Clean Water Act to develop
more stringent TMDLs (including WLAs and
LAs) than are required herein, providing that
all LAs in suchTMDLs reflect actual
nonpoint source loads or those loads that can
reasonably he expected to occur within a
reasonable time period as a result of •
implementing nonpoint source controls.:
6. Accumulation in Sediments. TMDLs
shall be sufficiently stringent so as to prevent
accumulation of the pollutant of concern in
sediments to levels injurious to designated or
existing uses, human health, wildlife and
aquatic life. TMDLs shall consider
contributions to the water column from
sediments inside and outside of any
applicable mixing zones.
7, Wei Weather Events. This guidance does
not provide specific procedures for wet
weather events. However, some of ihese
procedures may be deemed appropriate for
such purposes on a case-by-case basis,
8. Background Concentrations of
Pollutants, The representative background
concentration of pollutants shall be
established in accordance with this
subsection to develop TMDLs and to
determine reasonable potential throughuse
of procedure S of this appendix Such
loadings may be accounted for in a TMDL
through an allocation to a single
"background" category, or through
individual allocations to the various
background sources,
:• ."a..Requirements for Calculating •"•' •
Background. "Background'' represents all
loadings that (1) Flow from upstream waters
into the specified watershed, water body or- "
water body segment fbr which a TMDL is''
being developed, (2) enter the specified
watershed, water body or water body
, segment through atmospheric deposition or
sediment release or resuspeasiori, or (3)
occur within the watershed, water body or
water body segment as a result of chemical
reactions. Background concentrations shall ;
be determined on a case-by-case basis using
acceptable .available data on the specified
.watershed, water body or water body
segment, or on similar water bodies, and bast
professional judgement Available data shall
include available ambient water column :
measurements, caged fish tissue
measurements, and pollutant loading data.
When determining what available data are
acceptable, best professional judgement
should be used,-including consideration of
the sampling locatipn and the reliability of
the data through eomparisonio reported •
analytical detection levels and quantification
levels; . :
b. Calculation Requirements. Except as
provided below, the representative
background concentration for a pollutant •-:.--•
shall be established as the geometric mean of;
i. Acceptable available water column data:
ii. Water column concentrations estimated
through use of acceptable available caged fish
tissue data; or :
iii. Acceptable available mass loading data
used to estimate water column levels.
When more thaa one of the above three
data sets exist, best professional judgement
should be used to select .the one data set most
likely to accurately estimate background
concentrations, in utilizing mass loading
data, pollutant degradation and transport
information raay be considered.
In certain circumstjances, caged fish tissue
data or ambient monitoring data may be used
to estimate ambient concentrations at a given
upstream location, and data on mass loadings
upstream may be used to adjust that value to
the background level entering the water body
or water body segment of concern.
For the purpose of calculating the
geometric mean, data reported as below the
detection level shall be assumed to be one-
half of the reported detection level; data
reported as above the detection level but
below the quantification level shall be
assumed to be the detection leys! plus one-
half of the difference between the reported
detection level and the reported
quantification levei When all of the
acceptable available data in a data set ojr
category such as water column, caged fish
tissue or mass loading data, are below the
level of detection for a pollutant, then all tha
• data for that pollutant in that data set shall
be assumed to be zero,
9. TMDL Allocations. Nonpomt source load
allocations shall be based on: a. existing
loading rates if changes in loading rates are
not anticipated; b. anticipated increased
loading rates; or c. anticipated lower loading
rate if such lower loading rate is technically
reasonable and anticipated to occur within a
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reasonable tima period as a result of
implementation of best management
practices or other load reduction measures.
la determining whether any expected load
reduction? aro technically reasonable and
will occur within a reasonable period of time,
technical and institutional factors should be
considered. These decisions are case-specific
and should reflect the particular TMDL
under consideration. The portion of the
loading capacity not assigned to nonpoint
sources, or to a MOS, or reserved for future
growth is allocated to point sources. Upon
reissuenee, NPDES permits for these point
sources must Include limitations consistent
with tha WLAs in EPA approved or EPA
established TMDLs.
10. Effluent Flow. If WLAs are expressed as
concentrations of pollutants, the TMDL shall
also indicate the point source effluent flows
assumed in the analyses. Mass loading
limitations established in NPDES permits
must bo consistent with both the WLA and
assumed effluent flows used in establishing
tha TMDL.
11. New Source or Discharger. TMDLs may
include reserved allocations of loading
capacity to accommodate future growth and
additional sources. Where such reserved
allocations are not included in a TMDL, a
new or expanded discharge cannot be
permitted unless the TMDL is revised in
accordance with these procedures to include
• WLA for the new or expanded discharge.
B, Misting Zones for Bsoaccumulative
Chemicals of Concern (BCCs).
Notwithstanding any other provision in these
ruin, tho following requirements (or any
more stringent requirement established in
accordp.net) with section 510 of the Clean
Water Act) shall be applied in TMDLs for
BCCs:
I. Up until {insert 10 years from the
effective date of tha final rule], mixing zones
for BCCs may be allowed for existing
dischargers pursuant to the procedures
specified in sections C and D of this
procedure. However, for implementation of
numeric or narrative criteria and values
(Including, but not limited to HCC, HCV,
HNV, HNC, wildlife criteria and values, and
chronic aquatic criteria and values),
Individual WLAs for discharges to the open
waters of tha Great Lakes shall assume no
greater dilution than one part effluent to ten
parts receiving water.
2. No later man [insert 10 years from the
effective data of ths final rule], there shall be
no mixing zones available) to existing
dischargers for BCCs. Accordingly, the WLAs
for existing dischargers shall be such as are
Decenary to attain water quality standards
for BCCs at tha point of discharge. Thus, they
shall bo set (1) equal to the most stringent
water quality criteria or values for the BCCs
in question, or (2) at a more stringent level
than the most stringent water quality criteria
or values if necessary due to background
concentrations to meet such criteria and
values at the point of discharge. Permits
Isfuod within five years prior to [insert 10
years from tha effective date of the final rule]
must include a more stringent set of
limitation* applicable on [insert 10years
from tha effective data of the final rulei if
necessary to implement this requirement
3. Beginning on the effective date of these
procedures, there shall be no mixing zones
for BCCs available to new dischargers or new
sources. Accordingly, the WLAs for new
dischargers shall be such as are necessary to
attain water quality standards for BCCs at the
point of discharge. Thus, they shall be set (1)
equal to the most stringent water quality
criteria or values for the BCCs in question, or
(2) at a more stringent level than the most
stringent water quality criteria or values if
necessary due to background concentrations
to meet such criteria and values at the point
of discharge.
4. States may grant mixing zones beyond
the dates specified in paragraphs 2 and 3 of
this section, where it can be demonstrated on
a case-by-case basis that failure to grant a
mixing zone would preclude water
conservation measures that would lead to
overall load reductions in BCCs, even though
higher concentrations of BCCs occur in the
effluent. Such mixing zones must also be
consistent with sections C and D of this
procedure.
C. Deriving TMDLs for Discharges to Lakes.
This section addresses conditions for
deriving TMDLs for Open Waters of the Great
Lakes (OWGL), inland lakes and other waters
of the Great Lakes System with no
appreciable flow relative to their volumes.
1. Individual point source WLAs shall
assume no greater dilution than one part
effluent to 10 parts receiving water
(containing background levels of pollutants)
for implementation of numeric or narrative
chronic criteria and values (including, but
not limited to Tier I and Tier II HNVs, HCVs
and chronic aquatic life and wildlife criteria
and values), unless; subject to restrictions for
BCCs in section B of this procedure, an
alternative mixing zone is demonstrated as
appropriate in a mixing zone study
conducted pursuant to subsection 3 of this
section.
2. Appropriate mixing zone assumptions to
be used in calculating load allocations for
nonpoint sources shall be determined,
consistent with applicable State
requirements, on a case-by-case basis by the
authority establishing the TMDL.
3. Data generated by mixing zone studies
conducted by any interested party shall be
used to establish allocations when, in the
best professional judgement of the authority
establishing the TMDL, it is determined that
the mixing zone study demonstrates that a
dilution allowance other than those specified
in or established pursuant to sections C.I and
C.2 of this procedure is appropriate for the
protection of designated and existing uses,
and implementation of numeric and narrative
criteria and values. Mixing zone studies shall
address factors identified by the authority
establishing the TMDL, including, but not
limited to, density or temperature
stratification of the water body, dispersion of
the effluent discharge relative to situations
such as the location of a water supply intake
and critical biological habitat areas.
4. In cases where background
concentrations exceed criteria or values,
WLAs shall be set equal to zero or a multiple
source TMDL shall be established that '
ensures attainment of criteria or values and
control of BCCs pursuant to section B of this
procedure. • <
5. A separate check is made to assure that
the final WLAs provide, for attainment of
acute aquatic life criteria and values at the
boundary of any acute mixing zone allowed
under State law.
D. The Tributary Basin Mass Balance
TMDL Approach. The basin approach to
developing TMDLs addresses all known
sources of a pollutant in a drainage basin in
a single analysis. Where it is either not
required or not feasible to develop a basin-
wide TMDL, the regulatory authority shall
develop a TMDL for a smaller geographic
unit as necessary. The TMDL analysis shall
be undertaken pursuant to the following
steps:
1. Calculation of the Tributary Basin
Loading Capacity. The loading capacity is
initially calculated at the furthest •
downstream location in the drainage basin.,
The maximum allowable loading consistent
with the attainment of each numeric criterion
or value for a given pollutant is determined
by multiplying the criterion or value by the
flow at the furthest downstream location in
the tributary basin at the design flow
condition below:
a. Harmonic mean flow for human health
criteria or values. ,-..'•
b. 30-day, five-year low flow for wildlife
criteria or values. . .
c. 7-day, 10-year low flow or 4-day, 3-year
biologically-based low flow for chronic
aquatic life criteria or values. - ...
The lowest load is then selected as the
loading capacity. (
2. Inventory of Baseline Pollutant Loads.
An inventory of pollutant loadings (including
natural background) from all known sources
in the tributary basin shall be constructed.
a. The inventory for point sources uses a
pollutant loading baseline which should, as
appropriate, be derived from:
i. The permit limit(s) of sources
discharging the pollutant of concern. The
limits may be technology-based limits, water
quality-based limits, or a combination of ,
both. Actual effluent flow rates are used to
convert concentration-based permit limits to
an estimate of mass of pollutants discharged
overtime.
ii. The level of treatment currently required
or required pursuant to an enforceable
schedule of compliance. In appropriate
circumstances this could be BAT limits for
industrial discharges or secondary treatment
limits for POTWs.
iii. Actual loadings of a pollutant from a
facility when, for example, a limitation for
the pollutant is not included in the facility's .
permit. . '•!"""'
b. The inventory of nonpoint source
pollutant loadings includes contributions
from urban runoff, agricultural runoff,
groundwater contributions (including
groundwater contaminated by leaching from
landfill or industrial waste disposal sites),
atmospheric deposition and resuspension/
resolution from contaminated sediment.
Measured loading rates shall be used, when
available, or best estimates calculated.
Estimates should be based on loadings
expected after implementation of nonpoint .
source controls expected to occur within a
reasonable time period. , ,
3. Environmental Fate. The inventory of
baseline loadings conducted in sections D.2
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31037
and D.7 of this procedure and the site-
specific cross checks in sections D..8 and D.9
of this procedure shall be based on the.,
assumption that a pollutant does not degrade.
If, however, each of the following conditions -.
are met, the regulatory authority may take
into account degradation of a pollutant:
a. Scientifically valid field studies or other
relevant information demonstrate that
degradation of the pollutant will occur under
the full range of .environmental conditions
expected to be encountered; and
b. The field studies and other relevant
information address other factors that affect "
the level of pollutants in the water column
including, but not limited to, resuspension of
sediments, chemical speciation, and
biological and chemical transformation.
4. Establish the Basin Margin of Safety
(MOS). The basin margin of safety maybe
represented as a portion of the loading
capacity whiclrmust remain unallocated to
account for the uncertainties in deriving the
TMDL. Identification of a MOS should reflect
, consideration of the baseline loading chosen
to develop the inventory (e.g., permitted
versus actual loads, estimated versus
measured nonpoint loads) as well as
uncertainties in calculating loading capacity.
For example, the MOS may vary depending
on the degree of uncertainty associated with
predicted nonpoint source loadings. The
basin MOS will be unique and specific for
each tributary basin depending on the degree
of uncertainty. .
5. Compare Allowable Loading with
Baseline Loading. Compare the difference of
the loading.capacity calculated in section D.I
of this procedure minus any specified MOS
. calculated in section D.4 of this procedure to
the inventory baseline load calculated in
section D.2 of this procedure from all sources
for the pollutant of concern. If the baseline
load is greater than the difference of the -
loading capacity minus any specified MOS, ,
then the tributary basin is water quality- ~
limited'and a TMDL must be developed. If
the baseline load is less than the difference
of the loading capacity minus any specified
•MOS, the basin is not water quality-limited
and a TMDL for the entire basin is not
necessary; Whether or not a TMDL for the
entire basin is required, a mass balance cross
check, as described in sections D.8 and D.9
of this procedure shall be conducted in the
vicinity of each source to determine if a
TMDL for a segment of the basin is necessary.
6. Identify Load Reductions Subject to
Allocation. For a water quality-limited basin,
the portion of the pollutant load which must
.be reduced to meet water quality standards
shall be equal to the baseline load'minus the
loading capacity adjusted by the MOS. This
represents the load reduction which must be
, achieved through new or revised load and/
or wasteload allocations in order to meet
water quality standards at the downstream
terminus of the'basin. Additional reductions
may be necessary as determjned.,in sections
D.8 and D.9 of this procedure to ensure
attainment of water quality standards
throughout the basin. ' \\ .-.'.-.
'7. Conduct Allocation. The WLAs and LAs
shall be established by a reasonable process
for the particular basin under investigation.
Examples of allocation methods include but.
are not limited to;'.,.. . ....' .
a. Reduction of all sources proportional'to
then-current share of the baseline load. ,
b. Equal percent reduction. '
c. Equal effluent concentrations. ,
d. Most efficient reductions by selected
sources.
In no event shall a load allocation be set
.at a level which reflects an unreasonable
expectation of load reductions that will be
.attained by a nonpoint source within a
reasonable time period. .
8. Mass Balance Site-specific Chronic
, Allocation Cross-check. The basin approach
to the TMDL/allocation analysis initially
focuses on attainment of water quality
standards at the selected downstream
location. It must also be determined whether
standards will be met at all locations within
the basin.
At each individual point source location, a
site-specific cross-check shall be performed
that generates a WLA for the source that is
necessary to implement all water quality
standards for protection from chronic effects
at that location. Such cross-checks take into
.consideration background concentrations
immediately upstream of the point source,
any applicable State mixing zone policies
and a margin of safety to account for
uncertainties. .
Permittees may be required to conduct
mixing zone demonstrations in accordance
with directives of the authority establishing
the TMDL where the authority determines
that such a demonstration is necessary to
adequately conduct the basin TMDL analysis
or to evaluate chronic toxicity conditions at
the edge of any applicable mixing zone.
A site specific chronic cross-check is also
conducted with respect.to nonpoint source
loadings, and may indicate that reduced
loadings are necessary in the vicinity of the
nonpoint source to attain water quality
standards there. It may be appropriate to
reduce the LA for the nonpoint source to
reflect the requisite load reduction if it can
' reasonably be expected that such a load
reduction will hi fact be achieved within a
reasonable time period. Otherwise, it maybe
necessary to reduce the WLAs of upstream
point sources in order to ensure that water
quality standards are attained in the vicinity
of the nonpoint source. If either the LA for
a nonpoint source or the WLAs for upstream
point sources ate reduced for this purpose, it
is possible that .the allocations for some
sources'downstream in the tributary could be
increased hi the final TMDL from those,
initially calculated in the basin analysis,
depending on site-specific considerations
including individual acute and chronic cross-
checks.
9. Acute Criteria Cross-check. A separate
check shall be made to assure that acute
aquatic life criteria and values are met at the
boundary of any applicable acute criteria
mixing zone allowed under State law. If
mixing zones from two or more proximate
sources interact or overlap, the combined
•effect will be evaluated to determine if '
criteria and values will be met at the edge of
any applicable acute criteria mixing zones.
The acute criteria cross-check shall
include, but not be limited to, consideration
of:: (1) The expected dilution under all ...
effluent flow and concentration conditions at
idesign stream flow,-(2) maintenance of a zone
of passage for aquatic organisms and (3)
protection of'critical aquatic habitat.
A permittee may be required to conduct an
acute criteria mixing zone demonstration in
accordance with the directives of the
authority establishing the TMDL where the
authority determines that such a
demonstration is necessary to adequately
conduct the basin TMDL/allocation analysis
or is necessary to evaluate acute toxicity
conditions at the edge of the acute criteria
mixing zone. ; .
10. Determine the WLA. The more stringent
of the basin WLA, the site-specific chronic
WLA or site-specific acute WLA'is typically
applied as a WQBEL in the source's NPDES,
permit. However, where a more stringent
WLA is established as a result bf a site-
specific cross check than was initially
calculated using the basin-wide analysis,
revision of other WLAs or LAs initially
calculated under the basin approach may be
appropriate to reflect the additional
unallocated basin loading, depending on site-
specific considerations, including other , .
individual acute and chronic cross checks.
11. TMDL Validation. Where available,
ambient monitoring and other relevant data
should be evaluated to assess the accuracy of
the mass balance basin approach.
Comparison bf measured versus calculated
ambient concentrations (calculated from the
load inventory at the furthest downstream
location) can serve as a check on the
accuracy of the TMDL." Such analyses could •
demonstrate that a full-scale kinetic model
may be useful in developing a TMDL for the
basin. , •
Procedure 3B: Total Maximum Daily Loads,
Wasteload Allocations and Load Allocations
for Point and Nonpoint Sources; (Option B)"
A. General.Conditions of Application. The
following are conditions applicable to
establishing total maximum daily loads
(TMDLs) for all pollutants and waters within
the'Great Lakes System subject to the
exceptions included in 40 CFR 132.4.
1. TMDLs Required. TMDLs shall, at a
minimum, be established for each pollutant
for which it is determined pursuant to
procedure 5 of this appendix that there is a
reasonable potential that a'discharge will
cause or contribute to an exceedance of water
quality standards, and in advance of issuance
of any new or revised permit for the
discharge of such pollutant, unless it is
determined pursuant to these procedures that
a TMDL is not needed.
2. Load Reductions. TMDLs shall also be
prepared if the sum of existing point source
and nonpoint source (including natural
background) loadings exceeds the loading
capacity minus any specified margin of safety
for a substance. A TMDL must ensure
attainment of all numeric and narrative
criteria and Tier n values for a given
pollutant. TMDLs shall include WLAs for
point sources and LAs, for nonpoint sources
such that their sum is not greater than the
loading capacity minus the sum of any
specified MOS and reserve capacity for
future growth.
3. WLA Values. Point sources must be
regulated so as to ensure attainment of all .
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
downstream water quality standards. If
separate TMDLs are prepared for the same
pollutant In different segments of the same
drainage basin, and the separate TMDLs each
include WLAs for one or more of the same
point sources, then WQBELS shall be
consistent with the most stringent WLA in an
EPA approved or EPA established TMDL.
4. Momn of Safety (MOS). Each TMDL
shall include a MOS sufficient to account for
uncertainties in establishing the TMDL and
describe the manner in which a MOS is
provided. The MOS may bo provided by
waving a portion of the loading capacity
unallocated or by use of protective modeling
assumpUo&s to account for the uncertainties
in deriving the TMDL If a separate allocation
of loading capacity is set aside to provide a
MOS, the amount of such allocation shall be
described. If protective modeling
assumptions are relied on to provide a MOS,
the specific assumptions providing the MOS
•hull bo identified.
S. Mora Stringent Requirements. States may
exercise authority reserved to them under
section 510 of the Gean Water Act to develop
more stringent TMDLs (including WLAs and
LAs) than are required heroin, providing that
all LAs in such TMDLs reflect actual
nonpcirit source loads or those loads that can
reasonably be expected to occur within a
msotuiblt- time period as a result of ,
implementing conpoint source controls.
6. Accumulation in Sediments. TMDLs
shall be sufficiently stringent so as to prevent
accumulation of the pollutant of concern in
sediments to levels injurious to designated or
existing uses, human health, wildlife and
aquatic Ufa. TMDLs shall consider
contributions to the water column from
sediment! inside and outside of any
applicable mixing zones.
7. Wat Weather Events. This guidance does
not provide specific procedures for wet
weather events. However, some of these
procedures maybe deemed appropriate for
such purposes on a caso-by-caso basis.
8. Background Concentrations of
Pollutants, The representative background
concentration cf pollutants shall be
established in accordance with this
subsection to develop TMDLs and to
determine reasonable potential through use
of procedure 8 of this appendix. Such
loadings may be accounted for in a TMDL
through an allocation to a single
"background" category, or through
indlviduil allocations to the various
bsclgrijund sources.
a. Requirements for Calculating
Background "Background" represents all
losding* that: (1) Flow from upstream waters,
into the specified watershed, water body or
wa'.or body seipnent for which a TMDL is
being developed, (2) enter the specified
watershed, water body or water body
segment through atmospheric deposition or
sediment roloasa or re suspension, or (3)
occur within the watershed, water body or
water body segment as a result of chemical
reactions. Background concentrations shall
be determined on a case-by-case basis using
acceptable available data on the specified
watershed, water body or water body
segment, or on similar water bodies, and best
professional judgement. Available data shall
include available ambient water column
measurements, caged fish tissue
measurements, and pollutant loading data.
When determining what available data are
acceptable, best professional judgement
should be used, including consideration of
the sampling location and the reliability of
the data through comparison to reported
analytical detection levels and quantification
levels. ......................................... ' ........ , ............................. .
b. Calculation Requirements. Except as
provided below, the representative
background concentration for a pollutant
shall be established as the geometric mean of:
i. Acceptable available water column data;
ii. Water column concentrations estimated
through use of acceptable available caged fish
tissue data; or
iii. Acceptable available mass loading data
used to estimate water column levels.
When more than one of the above three
data sets exist, best professional judgement
^.....
likely to accurately estimate background
concentrations. In utilizing mass loading
data, pollutant degradation and transport
information may be considered.
In certain circumstances, caged fish tissue
data or ambient monitoring data may be used
to estimate ambient concentrations at a given
upstream location, and data on mass loadings
upstream may be used to adjust that value to
the background level entering the water body
or water body segment of concern.
For the purpose of calculating the
geometric mean, data reported as below the
detection level shall be assumed to be one-
half of the reported detection level; data
reported as above the detection level but
below the quantification level shall be
assumed to be the detection level plus one-
half of the difference between the reported
detection level and the reported
quantification level. When all of the
acceptable available data in a data set or
category such as water column, caged fish
tissue or mass loading data, are below the
level of detection for a pollutant, then all the
data for that pollutant in that data set shall
be assumed to be zero.
9. TMDL Allocations. Nonpoint source load
allocations shall be based on: a. existing
loading rates if changes in loading rates are
not anticipated; b. anticipated increased
loading rates; or c. anticipated lower loading
rate if such lower loading rate is technically
reasonably and anticipated to occur within a
reasonable time period as a result of
implementation of best management
practices or other load reduction measures.
In determining whether any expected load
reductions are technically reasonable and
will occur within a reasonable period of time,
technical and institutional factors should be
considered. These decisions are case-specific
and should reflect the .particular TMDL
under consideration. The portion of the
loading capacity not assigned to nonpoint
sources, or to a MOS, or reserved for future
growth is allocated to point sources. Upon
reissuance, NPDES permits for these point
sources must include limitations consistent
with the WLAs in EPA approved or EPA
established TMDLs.
10. Effluent Flow. If WLAs are expressed as
concentrations of pollutants, the TMDL shall
also indicate the point source effluent flows.
assumed in the analysis. Mass loading
limitations established hi NPDES permits
must be consistent with both the WLA and
assumed effluent flows used in establishing
the TMDL.
11. New Source or Discharger. TMDLs may
include reserved allocations of loading
capacity to accommodate future growth and
additional sources. Where such reserved
allocations are not included in a TMDL, a
new or expanded discharge cannot be
permitted unless the TMDL is revised in
accordance with these procedures to include
a WLA for the new or expanded discharge.'
B. Mixing Zones for Bioaccum ulatiys
Chemicals of Concern (BCCs).
Notwithstanding any other provision in these
rules, the following requirements (or any
more stringent requirement established in
accordance with section 510 of the Clean
Water Act) shall be applied in TMDLs for
BCCs: . ' , . -,..'''.....-. ',
il Up until [insert 10 years from the
effective date of the final rule], mixing zones
for BCCs may be allowed for existing
dischargers pursuant to the procedures
specified in sections C and Dof this
procedure. However, for Implementation of
numeric or narrative criteria and values
including, but not limited to HOC, HCV, .
HNV, HNC, wildlife criteria and values, and
chronic aquatic life criteria and values,
individual WLAs for discharges to open
waters of the Great Lakes shall assume no
greater dilution than one part effluent to ten
parts receiving water, and for discharges to
Great Lakes System tributaries shall assume
no greater dilution than that allowed under
section D.3.c.iii of this procedure.
2. No later than [insert 10 years from the
effective date of the final rule], there shall be
no mixing zones available to existing
dischargers for BCCs. Accordingly, the WLAs
for existing dischargers shall be such as are
necessary to attain water quality standards
for BCCs at the point of discharge. Thus, they
shall be set (1) equal to the most stringent
water quality criteria or values for the BCCs
in question, or (2) at a more stringent level
than the most stringent water quality criteria
or values if necessary due to background
concentrations to meet such criteria and
values at the point of discharge. Permits
issued within five years prior to [insert 10
years from the effective date of the final rule]
must include a more stringent set of
limitations applicable on [insert 10 years
from the effective date of the final rule] if
necessary to implement this requirement.
3. Beginning on [insert the effective date of
the final rule], there shall be no mixing zones
for BCCs available to new dischargers or new
sources. Accordingly, the WLAs for new
dischargers shall be such as are necessary to
attain water quality standards for BCCs at the
point of discharge. Thus, they shall be set (1)
equal to the most stringent water quality
criteria or values for the BCCs in question, or
• (2) at a more stringent level than the most
stringent water quality criteria or values if
necessary due to background concentrations
to meet such criteria and values at the point
of discharge.
4. States may grant mixing zones beyond
the dates specified in paragraphs 2 and 3 of
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21039
this section, where it can be demonstrated on
a case-by-case basis that failure to grant a
mixing zone would preclude water
conservation measures that woultJlead to
overall load reductions in BCCs, even though
higher concentrations of BCCs occur in the
efflueat. Such mixing zones must also be
c consistent with sections C and D of this .
'procedure. '.-..-
C. Deriving TMDLs for Discharges to Lakes.
.This section addresses conditions for
deriving TMDLs for Open Waters of the. Great
Lakes (QWGL), inland lakes and other waters
of the Great Lakes System with no
appreciable flow relative to their volumes.
1. Individual point source WLAs shall
assume no greater dilution than one part
effluent to 10 parts receiving water
(containing background levels of pollutants)
for implementation of numeric or narrative
chronic criteria and values (including, but
not limited to Tier I and Tier EHNVs, HCVs,
chronic aquatic life, and wildlife criteria and
values), unless, subject to restrictions for
BCCs in section B of this procedure, an
alternative mixing zone is demonstrated as
appropriate in a mixing zone study
conducted pursuant to section E of this .
procedure. - •
. a. Implementing Numeric Criteria and
, Values. Unless an alternative mixing zone is
approved, WLAs based upon protection of
aquatic life, wildlife and human health from
chronic effects shall not exceed:
WLA < 1 l(criterion) - IQ(background)
Where:
Criterion = a numeric criterion or value
designed to protect aquatic life, wildlife
criterion or value, and/or human health
from chronic adverse effects (including,
but not limited to a Tier I or Tier IIHNV,
HCV, chronic aquatic life criterion or
value, or a wildlife criterion or value
derived pursuant to this Guidance)
specified in units of mass per unit of
volume; -. '.-.'.'
Background = background concentration
, determined pursuant to section A.8 of
this procedure; specified.in units of mass
per unit of volume; and
A demonstration for a smaller or larger
mixing zone may be provided, approved and
implemented in accordance with section E of
this procedure. In no case shall the
1 permitting authority grant a mixing zone
based on a mixing zone demonstration which
exceeds" the area where discharge-induced
mixing occurs.
2. Appropriate dilution assumptions to be~~
used in calculating load allocations for .
npnpoint sources shall be determined,"
consistent with applicable State
requirements, oh a case-by-case basis by the
authority establishing the TMDL.
3. In cases where background
concentrations.exceed numeric or narrative
criteria or values, the WLA shall be set to
zero or a multiple source TMDL shall be
established that ensures attainment of criteria
or values and control of BCCs pursuant to
section B of this procedure.
4. WLAs based on acute aquatic life criteria
or values shall not exceed the Final Acute
Value.
' 5. The final TMDL shall include the most
stringent of the WLAs derived pursuant to
sections C.I, 3 and 4 of this procedure.
. p. Deriving TMDLs and WLAs/LAsfor
Discharges toGreatLakesSystem Tributaries.
This section applies to tributaries and
connecting channels of the Great Lakes that
exhibit appreciable flows relative ,to their
volumes, . ; .. ' . .
1. Stream design flow. The appropriate
stream design flow used in TMDL ~
development shall be: ••••••
a. Either the 7-day, 10-year low flow
(7Q10) or the-4-day, 3-year.biologically-based
design flow for chronic aquatic life criteria or
values; .... •-'...
. b. The harmonic mean flow for human
health criteria or values; and
c. The 30-day, 5-year low flow (30Q5) for
wildlife criteria or values.
2. Tributary Basin. When a TMDL is
established for a tributary basin or watershed
within a tributary basin:
a. An adequate MOS shall be identified in
the TMDL and shall include but may not be
necessarily limited to the unused capacity
provided by not utilizing more than the
allowable dilution flow defined in section
D.3.C.U of this procedure; "
b. When available information indicates
that a mixing zone for a point source extends
in an OWGL'or CCGL, the WLA is, :
determined using the more stringent dilution
allowance provided in either section C.I or
D,3.c of this procedure;
c. WLAs shall not exceed the FAV to
ensure protection of aquatic life'from acute
effects;
d. The WLA for a particular point source
shall be the more stringent of either:
i. The portion of the loading capacity for
the basin or. portion thereof, which is not
allocated to.LAs, MOS, reserve capacity (if
any) and WLAa-for other point source
dischargers; or
ii. The WLA developed using the '
-procedures in section D.3 of this procedure.
e. Tributary basin TMDLs shall be based on
the assumption that a pollutant does not
degrade. If, however, each of the following
conditions are met, the regulatory authority
may take into account degradation of a
"pollutant: "-.-'
i. Scientifically valid field studies or other
relevant information demonstrate that
, degradation of the pollutant will occur under
the full range of environmental conditions
expected to be encountered; and ;
ii. The field studies and other relevant
information address other factors that affect
the level of pollutants in the water column •
including, but not limited to, resuspension of
sediments,chemicalspeciation,and, •
biological and chemical,transformation,
3. Source Specific TMDLs. Source specific-
TMDLs shall be calculated in accordance ,
with this section. The procedures in this
section are applicable only when background
concentrations (see section A.8 of this
procedure) at the source location prior to the
addition-of discharge pollutants do not
exceed criteria and values. In other
situations, the regulatory authority shall
develop a TMDL in accordance with section
D. 2 of this procedure. ,
a. An adequate MOS shall be identified in
the TMDL and shall include unused capacity
provided by' not utilizing more than the
allowable dilution flow determined in
section D.3.c.ii of this procedure..
b. Where there is information that a mixing
zone for a point source discharge extends
from a tributary into ah OWGL or a
•connecting channel, the WLA for that point
source discharge shall be determined by
applying the procedures in section C.1 of this
procedure or section D.3.C of this procedure,
whichever is more stringent.
c. Existing Sources. TMDLs based upon -.
chronic aquatic life, wildlife and human
health criteria or values shall be developed
in accordance with the following
requirements:' •
WLA<
< (criterion)[Qad +(l-f)(effluent flow)]-(backgix>und)Qad ,
effluent flow
(X).
Where: . v -
(Jritenon = a numeric criterion or
"value, designed to protect aquatic
. life, wildlife, and/or hum.ait health
from, chronic adverse effects
(including, but not limited to, a Tier
I or Tier H HNV, HCV, chronic
aquatic life criterion or value, or a
wildlife criterion or value derived .
pursuant to this procedure)
specified in units of mass per unit
of volume. . • ...:'.
ad = allowable dilution flow as
calculated in section D.3.c.ii of this
:procedure, -
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Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
f M fraction of the source flow that is
withdrawn from the receiving
water,
Effluent flow « flow rate of the
discharger specified in units of
volume per time,
Background ** background
concentration at the discharge
location calculated pursuant to
section A,8 and specified in units of procedure.
mass per unit of volume,
X = a conversion factor which
converts units of mass per unit
volume to units of mass per unit
time.
ii. The allowable dilution flow [QaJ will be
_ __ 1 * * t il 1 J • V*-*J KAOtHO* M4.CL4A «4VfU Uklk -J.UtJt> IH.IU-H. WWV| I.UU
determined by mulbplytag the stream design ^^ fraction ^ be no ffeater than the
flow by the dilution fraction specified in «,« fcllnwina «nna«nm
either section D.3.c.iii or section E.3 of this
iii. Unless an alternative mixing zone is
allowed consistent with section E, the
dilution fraction is based upon the ratio of
the 7Q10 to the effluent flow. If the ratio is:
(a) less than or equal to 250, the dilution
fraction shall be no greater than 0.25;
(b) greater than 250 but less than 300, the
result of the following equation:
_, . "••• ;'••:•: 103-0^1(7Q16/Source Flow)
Dilution fraction = —
(c) is equal to or greater than 300, the
dilution fraction shall be no greater than 0,1.
d, New Sources. WLAs based upon chronic
aquatic Ufa, wildlife and human health
criteria or values shall equal the criteria or
value*, unless a mixing study is provided,
approved, and implemented in accordance
with soction E of this procedure. In no case
shall • demonstration result in a mixing zone
•which provides greater dilution than is
provided by section D.3.c.ii of this
procedure,
e. Existing and Mew Sources. WLAs based
on aculo aquatic lifo criteria or values for
both existing and new sources shall not
exceed the Final Acute Value.
f. The final WLA for an existing point
source is tha most stringent value calculated
under paragraphs c and e. The final WLA for
*« new point source Is the most stringent
value calculated under sections D.3.d and
D.3.e of this procedure.
B. Mixing Zone Demonstration
Requirements. 1. A mixing zone
demonstration must:
i. Describe the degree of dilution occurring
at the boundaries of the proposed mixing
zone and the size, shape, and location of the
urea of mixing, including the manner in
which diffusion and dispersion occur;
b. Define the location at which discharge-
induced mixing ceases for sources to the
open waters of the Great Lakes;
c. Document the substrate character and
gsomorphology within the mixing zone;
d. Show that the mixing zone does not
in!«fo:a with or block passage offish or
aquatic lifo;
e. Show that the mixing zone does not
extend to drinking water intakes;
f. Show that the mixing zone would not
otherwise interfere with the designated uses
of the receiving water or downstream waters;
and
g. Document background water quality
concentrations.
2. la addition, the mixing zone
demonstration shall address the following
factors;
a. Whether or not adjacent mixing zones
overlap;
b. Whether organisms would be attracted to
Ine area of mixing as a result of the effluent
character;
c Whither the habitat supports endemic or
naturally occurring species;
d. That the mixing zone does not promote
undesirable aquatic life or result in a
dominance of nuisance species; and
e. That by allowing additional mixing/
dilution:
i. Substances will not settle to form
objectionable deposits;
ii. Floating debris, oil, scum, and other
matter in concentrations that form nuisances
will not be produced;
iii. Objectionable color, odor, taste or
turbidity will not be produced.
3. For situations where a mixing zone
demonstration, as set forth in sections E.I
and E.2 of this procedure, has been provided
by the point source or any interested party,
if the permitting authority approves the
demonstration made according to the
conditions outlined above, an adjustment for
existing sources of non-BCCs to the dilution
ratio specified in section C.I of this
procedure or the dilution fraction specified
in section D.3.c.iii of this procedure may be
made. The maximum adjustment to the
dilution ratio specified in section C.l.a of
this procedure shall reflect the dilution
available in the area where discharged
induced mixing occurs. The adjustment to
the dilution fraction in section D.S.c.iii of -
this procedure shall not increase the dilution
fraction to greater than 0.75.
4. The mixing zone demonstration shall be
based on the assumption that a pollutant
does not degrade within the proposed mixing
zone, except that the regulatory authority
may take into account degradation of a
pollutant provided each of the following
conditions are met:
a. Scientifically valid field studies or other
relevant information demonstrate that
degradation of the pollutant will occur under
the full range of environmental conditions
expected to be encountered; and
b. The field studies and other relevant
information include other factors that affect ...
the level of pollutants in the water column,
including, but not limited to, resuspension of
sediments, chemical speciation, and
biological and chemical transformation.
Procedure 4: Additivity
[Reserved]
Procedure 5: Reasonable Potential To Exceed
Water Quality Standards
If a permitting authority determines that a
pollutant is or may be discharged into the
Great Lakes System at a level which will
cause, have the reasonable potential to cause,
or contribute to an excursion above any Tier
I criterion or Tier E value, the permitting
authority shall incorporate a water quality-
based effluent limitation (WQPEL) in an
NPDES permit for the discharge of that
pollutant. When facility-specific effluent
monitoring data are available, the permitting
authority shall make this determination by ,
developing preliminary effluent limitations
and comparing those effluent limitations to
the projected effluent quality (PEQ) of the
discharge in accordance with the following
procedures. In addition, the permitting
authority shall use any relevant information
that indicates a reasonable potential to
exceed any Tier I criterion or Tier II value.
A. Developing Preliminary Effluent
Limitations on the Discharge of a Pollutant
From a Point Source /
1. In accordance with procedure 3 this
appendix, the permitting authority shall
develop preliminary wasteload allocations
for the discharge of the pollutant from the
point source to protect human health,
wildlife, acute aquatic life, and chronic
aquatic life, based upon any existing Tier I
criteria. Where there is no Tier I criterion, the
permitting authority shall calculate a Tier II
value for such pollutant and the preliminary
wasteload allocations shall be based upon
such values; Where there is insufficient data
to calculate a Tier II value, the permitting
authority shall apply the procedure set forth
in section D of this procedure to determine
whether data must be generated to calculate
a Tier II value.
2. The permitting authority shall develop
preliminary effluent limitations consistent
with the preliminary wasteload allocations
developed pursuant to section A.I of this
procedure, and in accordance with existing
State or Tribal procedures for converting
wasteload allocations into water quality-
based effluent limitations. At a minimum:
a. The preliminary effluent limitations
based upon criteria and values for the
protection of human health and wildlife shall
be expressed as monthly limitations;
b. The preliminary effluent limitations
-based upon criteria and values for the
protection of aquatic life from chronic effects
shall be expressed as either monthly •
limitations or weekly limitations; and
c. The preliminary effluent limitations
based upon the criteria and values for the
protection of aquatic life from acute effects •
shall be expressed as daily limitations.
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21041
B. Determining Reasonable Potential for
Pollutants Where There Are Ten or More
Effluent Data Samples • . ' ;..
1. If ID or more facility-specific efiliient
monitoring data samples are available for a
pollutant discharged from a. point SOTOTCB to
the Open Waters of the Great Lakes or to" a
free-flowing stream where the effluent flow
rats is less than the stream seven-day, 10-year
flow, the permitting authority shall apply the
following procedures:
a. The permitting authority shall specify
the PEQ as the greater of the mgyirnum
effluent concentration or the 99th percentile
of the distribution of the daily values of the
facility-specific effluent monitoring data. If
the PEQ as either the maximum effluent
concentration or calculated as the 99lh .
percentile of the distribution of the. data
exceeds the preliminary effluent limitation
based on the criteria and values for the
protection of aquatic life from acute effects
developed in accordance with section A of
this procedure, the permitting authority shall
establish a WQBEL in an NPDES permit for
such pollutant;
b. The permitting authority shall calculate
the PEQ as the 99th percentile of the
distribution of monthly averages of tlie
facility-specific effluent monitoring data. If
, the PEQ exceeds the preliminary effluent .
limitation based on criteria and values for the
protection of aquatic life from chronic effects,,
human health or wildlife developed In
accordance with section A of this procedure,
the permitting authority shall establish a
WQBEL in an NPDES permit for such
pollutant; and
c. The permitting authority shall cfdculate
the PEQ as the 99th percentile of the.
distribution of weakly averages of thi?
facility-specific effluent monitoring data. If '
the PEQ exceeds the preliminary effluent
limitation based on criteria and values to
protect aquatic life from chronic effects '
developed in accordance with section A of
this procedure, the permitting authority shall
establish a WQBEL in an NPDES permit for
such pollutant. '
d, As an alternative to the procedures set
forth in procedures S.B.I.a through S.B.l.c of
this appendix, the permitting author! ty may
calculate .the PEQ as the 95 percent
confidence level of the 95th percentile based
on a log-normal distribution of the effluent
concentration.,In calculating the PEQ, the
permitting authority shall identify'the , -
number of effluent samples and the
coefficient of variation of the effluent: data,
obtain the appropriate multiplying factor
from. Table 1 of procedure 6 of appendix F,
and multiply the maximum effluent
concentration by that factor. The coefficient
of variation of the effluent data shall be
• calculated as the ratio of the standard
'deviation of the effluent data divided by the
arithmetic average of the effluent data. If the
PEQ exceeds any of the preliminary effluent
limitations developed in accordance with -
section A of this procedure, the permitting
authority shall establish a WQBEL in an
: NPDES permit for such pollutant -
- 2. if 10 or more facility-specific effluent
monitoring data samples are available for a
' p'ollutant. discharged from a point source to
a free flowing, stream where the-effluent flow
rate is equal to or greater than the stream
seven-day, -ID-year flow, the permitting
authority shall apply the following
procedures: '
a. The permitting authority shall specify
the PEQ as the greater of the maximum
effluent concentration and the 99th
percentile of the distribution of the daily
values of the facility-specific effluent
monitoring data. If the PEQ, as either the
maximum effluent concentration or
calculated as the 99th percentile of the
distribution of the data, exceeds 50 percent
of the preluninary effluent limitation based;
on the criteria and values for the protection
of aquatic life from acute effects developed
in accordance with section A of this :
procedure, the permitting authority shall
establish a WQBEL in an NPDES permit for
such pollutant;
b. The permitting authority shall calculate
the P_EQ as the 99th percentile of the
distribution of monthly averages of the
facility-specific effluent monitoring data. If
the PEQ exceeds 50 percent of the
preliminary effluent limitation based on
criteria and. values for the protection of
aquatic life from chronic effects, human '
health or wildlife developed in accordance
with section A of this procedure, the
permitting authority shall establish a WQBEL
in an NPDES jsermit for such pollutant; and
c. The permitting authority shall calculate
the PEQ as the 99th percentile of the
distribution of weekly averages of the
facility-specific effluent monitoring data. If
the PEQ exceeds 50 percent of the
preluninary limitation based on criteria and
values to protect aquatic life from chronic
effects developed in accordance with section
•A of this procedure, the permitting authority
shall establish a WQBEL in an NPDES permit
for such pollutant.
.C. Determining Reasonable Potential for
Pollutants Where There Are Less Than Ten .
Effluent Data Samples
If less than 10 representative effluent data
samples are available for a pollutant
discharged from a point source, the
pannitting authority shall apply the
following procedures:
, 1. Calculate the PEQ as follows: a. -
Determine the number of data samples
available for the pollutant discharged from"
the point source and the corresponding
multiplying factor from Table F5-1 of this
appendix:
b. The PEQ shall be the product of the
appropriate multiplying factor and the
maximum effluent concentration.
2, If the PEQ exceeds any of the
preliminary effluent limitations developed in
accordance with section A of this procedure,
the permitting authority shall establish.a
WQBEL in an NPDES permit for such
pollutant -
D. Developing Necessary Data To Calculate
Tier H Values Where Such Data Does Not
Currently Exist
1. Except as provided in sections D.2, D.3
or E of'this procedure, for. each pollutant
listed in Tables of part 132 that a permittee
reports as known or believed to be present in
its effluent at a level for. which data sufficient
tp calculate Tier n values for noncancer -'-•••.'
human jiealth, wildlife, acute aquatic life and
chronic aquatic life does not .exist, the
permitting authority shall:
a. Use all available, relevant information,
including Quantitative Structure Activity ,
Relationship information and other relevant
toxicity information, to estimate ambient
screening values for such pollutant which : ..
will protect-humans from health effects other
than cancer, aquatic life from,acute and
chronic effects, and wildlife,-;
b. In accordance with procedure 3 of this
appendix, the permitting authority shall
, develop preliminary wasteload allocations
for the discharge of the pollutant from the
point source to protect human health,
wildlife, acute aquatic life, and chronic
aquatic life, based upon the estimated
ambient screening values. .
c. The permitting authority shall develop
preliminary effluent limitations ia
accordance with section A.2 of this
procedure, and consistent with the
preliminary wasteload allocations developed
in accordance with section D.l.b of this., ;
procedure.
d. The permitting authority shallcompare
\thePEQdevelopedaccordingtothe
procedures set forth in sections B and C of
this procedure to the preliminary effluent
limitations developed in accordance with
sectipn D.l.c of this procedure. If the PEQ
exceeds any of the preliminary effluent
limitations (or 50 percent of any of the
preluninary effluent limitations where the
pollutant is being discharged into a free-
flowing stream where the discharger design
flow is equal to or greater than the stream 7- -
day, 10-year flow), the permitting authority
.' shall generate, or require the permittee to
generate, the data necessary to derive Tier H
values fer noncancer human health, wildlife,
• acute aquatic life and chronic aquatic life.
e. The data generated in accordance with,
section D. i.d of this procedure shall be used
ia calculating Tier II values as required under
section A.1 of this procedure.
2. A permitting authority is not required to
apply the procedures set forth in section D,i
of this procedure, and include WQBELs to
protect aquatic life on the,discharge of any
pollutant listed in Table 6 of part 132, other
than bioaccumulative chemicals of concern,
by an existing point source into the Great
Lakes System, if: .
a. There is insufficient" data to calculate a /
Tier I criterion or Tier II value for aquatic life
for such pollutant; '•'.-.-•••
b. The permittee has demonstrated through
a biological assessment that there are no
acute or chronic effects on aquatic life in the
receiving water; and'
• c, The permittee has demonstrated in
accordance with procedure 6 Of this
appendix .that the whole effluent does not
exhibit acute pr chronic toxieity,
3, Nothing in sections D,l or D.2 of this
procedure shall preclude or deny the right of .
a permitting authority to: , , '/;
a. Determine, in the absence of the data -.-• •
necessary to .derive a Tier II value, that the ,
discharge of the pollutant will cause, have
the reasonable potential to cause or
contribute to an excursion above a narrative
criterion for water quality; and . ' -^
b. To incorporate a WQBEL for the ,
'- pollutant into an NPDES permit : ..-;,., -.
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21042
Federal Register / Vol. 58, No. 72 7 Friday, April 16, 1993 7 Proposed Rules
4. If the permitting authority develops a
water quality-based effluent limitation
consistent with section D.3 of this procedure,
it shall not be obligated to generate or require
tho permitted to generate the data necessary
to derive a Tier II value or values for that
pollutant
B. Determining Reasonable Potential for
Intake Water Pollutants
1. The permitting authority may determine
that there is no reasonable potential for the
discharge of an identified intake water
pollutant or pollutant parameter to cause or
contribute* to an excursion above a narrative
or numeric water quality criterion within a
State or Tribal water quality standard if the
permittee demonstrates that:
a. The facility withdraws 100 percent of
the intake water containing the pollutant
from the same body of water into which the
discharge is made;
b. The facility docs not contribute any
additional mass of the identified intake water
pollutant to its wastewaterj
c. The facility does not alter the identified
intake water pollutant chemically or
physically hi a manner that would cause
advene water quality impacts to occur that
would not occur if the pollutants were left in-
strearn;
d. The facility docs not increase the
identified intake water pollutant
concentration at the edge of the mixing zone,
or at the point of discharge if a mixing zone
is not allowed, as compared to the pollutant
concentration in the intake water; and
e. The timing and location of the discharge
would not cause adverse water quality
impacts to occur from the discharge of the
identified intake water pollutant that would
not occur if the pollutants were left in-
stream.
2. Upon demonstration of the conditions La
section B.1 of this procedure, the permitting
authority is not required to include a water
quality-bused effluent limitation for the
identified intake water pollutant in the
facility's pormlt, provided:
a. The NPDES permit fact sheet or
statement of basis summarizes the basis for
the determination that there is no reasonable
potential for the discharge of an identified
intake water pollutant to cause or contribute
to art excursion above a narrative or numeric
water quality criterion and references
appropriate supporting documentation
included in the administrative record;
b, The permit requires all influent, effluent,
and ambient monitoring necessary to
demonstrate that the conditions in section
E,l of this procedure are maintained during
the permit term; and
c. The permit contains a reopener clause
authorizing modification or revocation and
relssuance of the permit if new information
indicates changes in the conditions hi section
B.1 of this procedure.
3, Absent demonstration of the conditions
in section E.I of this procedure, the
parmltting authority shall use the procedures
tinder sections A through D of this procedure
to determine whether a discharge has the
reasonable potential to cause or contribute to
an excursion above a narrative or numeric
water quality criterion.
"' „;,; ,; •,'<".•: ,«;. ;,,••:! .",,: Vs;,,.;,, ',:>".; ',. ;••„>.';:•'.•
4. This section does not alter the
permitting authority's existing obligation to
develop effluent limitations consistent with
the assumptions and requirements of any
available waste load allocation for the
discharge prepared by the State or Tribe and
approved by EPA pursuant to 40 CFR 130.7.
F. Other Applicable Conditions
1. In addition to the above procedures,
effluent limitations shall be established to
comply with all other applicable State, Tribal
and Federal laws and regulations, including
technology-based requirements and
antidegradation policies.
2. When determining whether water,
quality-based effluent limitations are
necessary, information from chemical-
specific, whole effluent toxicity and
biological assessments shall be considered
independently.
3. If the geometric mean of a pollutant in
fish tissue samples collected from a water
body exceeds the tissue basis of a Tier I
criterion or Tier n value, after consideration
of the variability of the pollutant's
bioconcentration and bioaccumulation in
fish, each facility that discharges detectable
levels of such pollutant has the reasonable
potential to cause or contribute to an
excursion above a Tier I criteria or a Tier II
value and the permitting authority shall
establish a WQBEL for such pollutant hi the
NPDES permit for such facility.
Tables to Procedure 5 of Appendix F
TABLE F5-1
Number of samples
1
2
3
4
5
6
7
8
9
Multiplying fac-
tor for CV=0.6
6.2
3.8
3.0
2.6
2.3
2.1
2.0
1.9
1.8
Procedure 6t Whole Effluent Toxicity
Requirements for Point Sources
A. Whole Effluent Toxicity Requirements
The following requirements shall apply to
all discharges:
1. No discharge shall exceed 1.0 acute toxic
unit (TUJ at the point of discharge;
2. No discharge shall cause or contribute to
causing any point in a receiving water to
exceed 1.0 chronic toxic unit (TUJ; provided
that, at the discretion of the permitting
authority, the foregoing requirement shall not
apply, (i) within a mixing zone, or (ii) in any
portion of a receiving water for which a
permitting authority nas demonstrated that
due to the site-specific physical and
hydrological conditions, it is unnecessary to
apply any chronic whole effluent toxicity
(WET) requirements to protect aquatic life;
and
3. No discharge shall cause or contribute to
causing an excursion above any numeric
WET criteria or narrative criteria for water
quality within a State or Tribal water quality
standard. • • ..
B. WET Test Methods
All WET tests performed pursuant to :this ,
procedure 6 shall be performed in
accordance with test procedures approved
under 40 CFR part 136. If there are no test
procedures for WET approved under 40 CFR
part 136, all WET tests performed pursuant
to this procedure shall be performed in
accordance with:
1. "Methods for Measuring the Acute
Toxicity of Effluents and Receiving Waters to
Freshwater and Marine Organisms", EPA/
600/4-90/027;
2. "Short-Term Methods for Estimating the
Chronic Toxicity of Effluents and Receiving
Waters to Freshwater Organisms", EPA/600/
4-89/001, and Supplement, EPA/600/4-89/
OOla (except Method #1001 and #1003); or
3. other acute or chronic toxicity testing
methods determined to be acceptable by the
permitting authority,
C. Permit Conditions
1. Where a permitting authority determines
that a discharge violates or has the reasonable
potential to violate the requirements of
section A of this procedure, the permitting
authority:
, a. Shall establish a water quality-based
effluent limitation (WQBEL) or WQBELs for
WET to ensure compliance with section A of
this procedure;
b. Shall calculate the WQBEL to ensure
compliance with the requirements of section
A.2 of this procedure based upon the dilution.
calculations specified in sections C and D of
procedure B3 of this appendix;
c. May allow an appropriate schedule of
compliance consistent with procedure 9 of
this appendix; and
d. May decide that WQBELs for WET are
not necessary if the State or Tribe's water
quality standard does not contain a numeric
criterion for WET, and the permitting
authority demonstrates in the fact sheet or
statement of basis of the NPDES permit that
chemical-specific effluent limits" are
sufficient to ensure compliance with section
A of this procedure. - ,
2. Where a permitting authority does not
determine that a discharge violates or has the
reasonable potential to violate the
requirements of section A of this procedure,
but the permitting authority lacks sufficient
data to demonstrate pursuant to section D
that the discharge does not violate or have
the reasonable potential to violate the
requirements of section A of this prodedure,
then the permitting authority shall include:
a. WET testing requirements in NPDES
permits to generate the data needed to
adequately characterize the aquatic toxicity
of the effluent; and , ' .
b. Appropriate language requiring the
initiation and completion of a toxicity
reduction evaluation by the permittee if the
toxicity testing data required by section
6.C.2.a of this appendix indicate that the
discharge violates or has reasonable potential
to violate the requirements of section A of
this procedure.
3. Where sufficient data are available for a
permitting authority to determine pursuant to
section D of this procedure that a discharge
does not violate or have the reasonable
potential to violate the requirements in
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Federal Register -/ Vol. 58, No. 72 / Friday, • April 16, 1993 / Proposed Rules
21043
section A of this procedure, the permitting
authority shall hot he required to include in
the permit those conditions set forth in
section C.2 of this procedure, hut may do so
at its discretion.
D. Reasonable Potential Determinations
"'. The permitting authority shall take Into
account the factors described in 40 CFR
122.44(d)(l)(ii} in determining whether a
discharge causes, has the reasonable
potential to cause, or contributes to a
violation of the requirements of section A of
this procedure. In cases where facility-
specific WET effluent data are available, a
permitting authority shall use the following
procedures hi determining whether a :
discharge .causes, has the reasonable
potential to cause, or contributes to a
violation of section A of this procedure:
1. The-permitting authority shall ,''.'.
characterize the toxicity of the discharge by;"
a. Averaging acute toxicity values collected
within the same day for each species; •
b. Averaging chronic toxicity values
collected within the same calendar month for
each species; and
c. When either chronic or acute toxicity
values are unavailable; estimating the
missing result by using ah effluent-specific :
acute/chronic ratio, except that when there is
no effluent-specific acute/chronic ratio, the
missing value shall be predicted using a
default acute/chronic ratio of 10.
2. A'discharge causes, has the reasonable
potential to cause, or contributes to a
violation of 1.0 TUa when sufficient effluent-
specific information demonstrates that
50%
% effect in 100% effluent
iV(BxRWC)
where B is the multiplying factor taken from
Table F6-1 of this procedure and RWC is the
receiving water concentration of the effluent
expressed in decimal form. Where there are
less than ten individual WET tests, the •
multiplying factor taken from Table F6-1 of
this procedure shall be based on a CV of 0.6.
Where there are ten or more individual WET
tests, the multiplying factor taken from Table
F8—1 qf this procedure shall be based on a
CV calculated as the standard deviation of
the WET tests by the arithmetic mean of the
WET tests, For discharges to Tributaries of
the Great Lakes System, RWC is determined
by dividing the source flow by the Q,
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Federal Register / Vol. 58, No. 72, / Friday, April 16, 1993 / Proposed Rules
TABLE F6-t.—REASONABLE POTENTIAL MULTIPLYING FACTORS: 95% CONFIDENCE LEVEL AND 95% PROBABILITY BASIS—
Continued ^
Number of samples
•jg ,
20 ..„.„.„.....
Coefficient of variation
0.1
1.1
1.1
0.2
1.1
1.1
0.3
1.2
1.2
0.4
1.3
1.2
0.5
1.3
1.3
0.6
1.4
1.4
0.7
1.5
1.4
0.8
1.5
1.5
0.9
1.6
1.5
1.0
1.6
1.6
1.1
1.7
1.7
1.2
1.8
1.7
1.3
1.8
1.8
1.4
1.9
1.8
1.5
1.9
1.8
1.6
2.0
1.9
1.7
2.0
1.9
1.8
2.0
2.0
1.9
2.1
2.0
2.0
2.1
2.0
Ptocedura 7: Loading Limits
Whenever a water quality-based affluent
limitation (WQBEL) is developed based upon
(ha provisions of procedures 3 and 5 of this
appendix, or other State procedures except
for pollutants which cannot be appropriately
expnsied in terms of mass, the WQBEL shall
bo established as both a concentration value
and an equivalent mass loading rate value.
A, Both values shall be consistent in terms
of dally or weekly, and monthly averages, or
la other appropriate time-related terms.
B. The mass loading values shall be
calculated using (he effluent flow rate values
that are consistent with those used in the -
development of WQBEL concentration values
pursuant to procedures 3 and 5 of this
appendix, or other State procedures.
Procedure 8: Water Quality-Based Effluent
Limitations Below the Levels of
Quantification
Whan a water quality-based effluent
limitation (WQBEL) for a pollutant is
determined to bo less than the minimum
lavcl (ML) of the most sensitive analytical >
technique specified In or approved under 40
CFR part 136, the permitting authority shall
ula the following strategy to regulate the
source of that pollutant in the NPDES permit
A, Permit Limit
Include the WQBEL in the NPDES permit,
specify an analytical method and
measurement frequency, and identify the
compliance evaluation level (GEL) for the
pollutant that is not to be exceeded. The GEL
is the level at which compliance with, an
effluent limit is assessed. The permittee shall
bo given the opportunity to demonstrate that
a higher level is appropriate because of
matrix interference.
B, Narrative Statement
Include permit text explaining that the
WQBEL for the pollutant is less than the GEL
of lha specified analytical method.
C. Daily, Weekly and Monthly Limits
Include text in each permit stating that any
discharge of a pollutant in amounts greater
than or equal to the daily CEL for that
pollutant is an exceedance. Include text
when a permit contains a weekly or monthly
limit, (i) requiring that all discharges
sampled during such time period be averaged
according to procedures established by the
permitting authority, and (ii) stating than an
average value greater than or equal to a
weekly or monthly CEL is an exceedance.
D. Program Requirement
Include a condition in the permit which
requires the permittee to develop and
conduct a pollutant minimization program.
The goal of the pollutant minimization
program shall be to reduce all potential
sources of the pollutant to maintain the
effluent at or below the WQBEL. The
minimization program shall, as a minimum,
include the following:
1. An annual review arid semi-annual
monitoring of potential sources of the
pollutant;
2. Quarterly monitoring for the pollutant in
the influent to the wastewater treatment .
system;
3. Submittal of a control strategy designed
to proceed toward the goal of maintaining all
sources of the pollutant to the wastewater
collection system below the WQBEL;
4. When the sources of the pollutant are
discovered, appropriate control measures
shall be implemented, consistent with the
control strategy; and
5. An annual status jeport shall be sent to
the permitting authority including:
a. All minimization program monitoring
results for the previous year;
b. A list of potential sources of the
pollutant; and
c. All action taken to determine and
eliminate the pollutant
E. Compliance Text
Include permit text specifying that the
permittee will be considered in compliance
during any time period if all applicable
discharge limits are being met, the Pollutant
Minimization Program described in section D
of this procedure is being fully performed,
and all other terms and conditions of the
permit are being fully satisfied.
F. BCCs
If the WQBEL is for a pollutant which is
aBCC:
1. Include a condition in the permit which
requires the permittee to determine if the
pollutant is bioconcentrating or
bioaccumulating in fish exposed to the
effluent. Resident fish monitoring/caged fish
monitoring, effluent pollutant
bioconcentration studies, and/or application
of other approvable procedures shall be
required as part of the permit condition.
2. To the extent that these studies reveal
unacceptable accumulation in fish tissue as
a result of the discharge, the control strategy
required by section D.3 of this procedure
shall be reviewed and modified as
appropriate. For purposes of the foregoing,
"unacceptable accumulation" shall be /
determined by: (i) Comparing the level of the
pollutant in the monitored fish tissue to the
level used to develop the water quality
criteria for that pollutant (accounting for the
variability of the bioconcentration test and
for the calculated dilution of the effluent
flow hi the receiving water), or (ii)
calculating the effluent concentration of the
pollutant from fish tissue monitoring and
comparing the result to the water quality
criteria for that pollutant (accounting for the
variability of the bioconcentration test and
for the calculated dilution of the effluent
flow in the receiving water).
G. Other Conditions
The permit may also require the
development and implementation of other
innovative monitoring programs. These
programs would be determined On a case-by-
case basis and may include:
1. New analytical equipment and methods
more sensitive than the analytical method
specified in the permit;
2. Internal waste stream monitoring and
mass balance modeling techniques; and
3. Other innovative monitoring techniques
capable of adequately determining the
compliance status of the effluent.
Procedure 9: Compliance Schedules
A. New or More Restrictive Limitations.fbr
New or Increasing Dischargers
When a permit is issued, reissued or
modified to contain an effluent limitation
derived from a Tier I criterion or Tier II
value, whole effluent toxicity criterion or
narrative criterion to address a new or -
increased discharge, the permittee shall
comply with the new effluent limitation
upon the commencement of the new or
increased discharge. - • •
B. New or More Restrictive Limitations for
Existing Discharges
1. Any existing permit which is reissued or
modified to contain a new or more restrictive
effluent limitation based upon a Tier I
criterion or Tier II value, whole effluent
toxicity criterion, or narrative criterion may
allow a reasonable period of time, not to
exceed the term of the permit or three, years,
whichever is less, for the permittee to comply
with that limit, provided that the Tier I
criterion. Tier II value, whole effluent
toxicity criterion, or narrative criterion was
adopted (or, in the case of a narrative
criterion, was newly interpreted) after July 1,,
1977.
, 2. If a permit establishes a schedule of
compliance which exceeds one year from the
date of permit issuance, the schedule shall
set forth, interim requirements and the dates
for their achievement. The time between
interim dates for compliance schedules
under this provision may not exceed one
year. If the tune necessary for completion of ;
any interim requirement is more than one
year and is not readily divisible into stages
for completion, the permit shall specify
interim dates which shall be at least annual
for the submission of progress reports toward
completion of the interim requirements and
indicate a projected completion date.
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21045
C. Delayed Effectiveness of Tier n
Limitations for Existing Discharges
Whenever a limit based upon a Tier II
value is included in a final permit issued to
an existing discharger, the permit may^
provide a reasonable period of time up to two
years in which to provide additional studies
necessary to develop a Tier I criterion or to
modify the Tier II value. In such cases, the
permit shall require compliance with the Tier
II limitation within a reasonable time no later
than three years after permit issuance and
contain a reopener clause allowing permit
modification if specified studies have been
provided by the permittee or any person
during the time allowed for generation of
additional data. If the permittee or any
person demonstrates through additional
studies that a revised'limit is appropriate,
that limit shall be incorporated through
permit modification,and a reasonable time
period allowed for compliance up to the
permit term. If the specified studies have
been performed and do not demonstrate that
a revised limit is appropriate, the permitting
authority may provide the permittee a
reasonable additional tune with which to
achieve compliance with the original effluent
limitation within the remaining term of the
permit. The limit revised based upon
additional studies is not affected by the anti:
backsliding provisions of section 402(o) of
the Clean Water Act.
D. Definitions , ': 1
Existing discharger. Any facility that.
commenced discharging prior to [insert the ,
effective date affinal rule], provided it is not,
an increasing discharger. '•'"-•!.•
Increasing discharger. An existing
discharger that on or after [insert the effective
dateoffinal.rule] has an increase in flow,
concentration or loading from that which was
previously specified in its permit.
New discharger. Any facility that
commences discharging on or after [insert the
effective date affinal ru/ej.
[FR Doc. 93-7832 Filed 4-15-93; 8:45,am]
BILLING CODE 6560-60-P
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21046 Federal Register / Vol. 58, No. 72 / Friday, April 16, 1993 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 122,123,131, and 132
[FRL-4613-8]
F1N204Q-AC06
Proposed Water Quality Guidance for
the Great Lakes System
AGENCY; U.S. Environmental Protection
Agency
ACTION: Proposed rule; correction.
SUMMARY: EPA is making corrections to
tho preamble to the proposed rule for
the Water Quality Guidance for the
Great Lakes System which appears
elsewhere in this separate part of the
Federal Register. The corrections
provide missing text and changes that
were inadvertently omitted during
editing of the proposed rule. In
addition, EPA is encouraging
commonters on the Guidance to provide
one copy of their comments in
electronic format
DATES: EPA will accept public
comments on the proposed Guidance
including the corrections until
September 13,1993. Comments
postmarked after this date may not be
considered.
ADDRESSES: An original and 4 copies of
all comments on the proposed Guidance
including the corrections should be
addressed to Wendy Schumacher, Water
Quality Branch (WQS-16J), U.S. EPA,
Region V, 77 West Jackson Blvd.,
Chicago, Illinois, 60604 (telephone:
312-886-0142), In addition, EPA
encourages commenters to provide one
copy of their comments in electronic
format, preferably 5.25" or 3.5" diskettes
compatible with WordPerfect for DOS,
FOR FURTHER INFORMATION CONTACT:
Kenneth A. Fenner, Water Quality
Branch Chief CWQS-16J), U.S. EPA
Region V, 77 W. Jackson Blvd.,,Chicago
Illinois, 60604 (Telephone: 312-353-
2079).
SUPPLEMENTARY INFORMATION: This
document provides corrections to
several paragraphs in the preamble to
tho proposed Water Quality Guidance
for the Great Lakes System ("Guidance")
developed under section 118(c)(2) of the
Clean Water Act (CWA), and published
elsewhere in this separate part of the
Federal Register. This Guidance, once
finalized, will establish minimum water
quality standards, antidegradation
policies, and implementation
procedures for waters within the Great
Lakes System in the States of New York,
Pennsylvania, Ohio, Indiana, Illinois,
Minnesota, Wisconsin, and Michigan,
including the waters within the
jurisdiction of Indian Tribes.
The corrections provide missing text
and changes that were inadvertently
omitted during editing of the proposed
rule, i ,_ f
Correction 1 •
„ " ;' I , • ''''!!' • ,: '•', '! , " H'" ' ' ' :'"'i ' ' ,,",* , ' .",' "iiL" -..' '
Replace the 17th paragraph in section
I.A.4.b of the preamble with the two
naw paragraphs below. The revision
corrects an inadvertent omission of text
that references the source of measured
concentrations of pollutants in fish
tissue in the Great Lakes system,
references a recent EPA study, and
requests additional comments. The two
new paragraphs would read:
These substances appear to be
approaching equilibrium in the Great
Lakes System at unacceptably high
levels due to continuing loadings froni
a variety of sources, such as: (1)
Historically contaminated sediments in
the embayments as well as the open
lakes; (2) tributary inputs resulting from
point sources, spills and direct runoff
from urban and rural areas, and/or
resuspension from contaminated
sediments; and (3) atmospheric
deposition of pollutants.
Concentrations measured.in 1990 in
lake trout in Lake Michigan of PCBs and
chlorinated pesticides exceed the fish .
tissue concentrations that correspond to
current EPA 304(a) water quality criteria
by several orders of magnitude (Table I—
1) (DeVault 1993a). As discussed above,
coho salmon respond much faster to
changes in water column concentrations
than lake trout. If a new equilibrium is
being reached given current mass
loadings, then substantial further
reductions in mass loadings to the lakes
will be necessary to eliminate fish
advisories.
EPA recently released a national
study on chemical residues in fish (EPA,
1992). Many of the fish samples
evaluated in the study were from sites
in the Great Lakes basin known to be
influenced by various point and
nonpbint sources. EPA invites
comments on the applicability of data
from the study to the analysis of toxic
pollutants in the Great Lakes ecosystem.
Correction 2
Replace the fifth paragraph of section
n.E.l.b of the preamble with the new
paragraph below. The editorial changes
that were inadvertently omitted clarify
the Agency's position that the proposed
Guidance would be applicable to
decisions under other statutes "to the
extent independent regulatory authority
requires compliance with the Clean
Water Act." The new paragraph would
read:
Finally, upon Incorporation into'
enforceable State, Tribal, or Federal
laws, the criteria and values or
appropriate site-specific modifications
developed under the proposed
Guidance will apply to a wide range of
regulatory decisions, including
decisions uader other statutes tt> the
extent independent regulatory authority
requires compliance with the Clean
Water Act. Examples of such
application include:
Correction 3
Replace the six&.paragraph of section
n.I of the preamble with the new
paragraph below. The text inadvertently
omitted reference to Table 5. The new
paragraph would read:
For pollutants other than those listed
in Tables 1, 2, 3, 4, and 5, the
requirements of § 132.5(e)(2) are
intended to ensure that State or Tribal
criteria methodologies and narrative
implementation procedures result in
criteria or values equal to or more
restrictive than the proposed Guidance
methodology produces.
Correction 4
Replace the fourth sentence of the
first paragraph of sectionTV.B.5 of the
preamble with the three new sentences
below. The text corrects a reference to
the chemicals that the Agency believes
may be affected by the use of
bioaccumulation factors. The three new
sentences would read:
This change will result in more
stringent criteria for a number of
chemicals in the Great Lakes system.
The chemicals most affected would be
those listed as bioaccumulative
chemicals of concern and potential
bioaccumulative chemicals of concern
in Table 6 of part 132, This change is
also consistent with EPA's existing
guidance ("Technical Support
Document for Water Quality-based
Toxics Control" (EPA 505/2-90-001)'
and draft "Assessment and Control of
Bioconcentratable Contaminants in
Surface Waters" (56 FR13150)).
Correction 5
Replace the third last paragraph of
section VII.D.S.g of the preamble with •
the new paragraph below. The editorial
changes that were inadvertently omitted
clarify .the scenario presented in the
preamble. The new paragraph Would
read;
In this scenario, the return to the
higher production rate may be subject to
antidegradation, depending on the ...
timing of the previous production
patterns and whether or not they are
reflected in the effluent limits and EEQ
baseline conditions established at the
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.Federal Register / Vol. 58, No. 72 I Friday, April 16, 199a /Proposed Rules
21047
time of. permit reissuance. As discussed
above, information from the preceding ;
permit term should be used to
determine the effluent quality. The
permit writer has the flexibility to use
the most representative information
from the preceding permit term in
making the determination. The permit
•writer could account for a recent • -' • -
downturn in production by setting the
effluent limits and establishing EEQ
baseline conditions to reflect conditions
prior to the downturn. In this, j:ase, '-,.
permit limits would aLready^e^et at
. levels that will accommodate^rlturn to
historic production levels. In contrast, if
a production decrease was in evidence
over the previous permit term and likely
to continue, the permit would likely ,
establish effluent limits and baseline
EEQ conditions at the level
representative of the previous permit
term, and a firm'seeking to return to .
production levels achieved hi an earlier
time period would be subject to
antidegradation (if changes to these
permit limits are necessary to
accommodate this increase in
production). _ ' .-
Correction 6
Replace the third sentence of the last
paragraph of section VILF.S.e of the
•preamble with the new sentence below.
The editorial changes that were
inadvertently omitted add the words "or
analyze the cost-effectiveness of a; -';
pollution prevention alternative" to the
sentence. The new sentence would read:
, While the proposed Guidance does
not explicitly require cost/benefit or
cosi effectiveness analyses, in .
determining what is prudent and
feasible EPA believes that the Director
will likely weigh the cost of the
pjollution prevention measures against
the benefits with regard to the
reductions in pollutant loading.or
analyze the cost-effectiveness of a
pollution prevention alternative.
Correction 7
Replace the last digit of the
Educational Resources Information
Center (ERIC) order numbers for
documents appearing in section Xm of
the preamble with the capital letter "D"
This change corrects a typographical
error in editing. For examplspthe ERIC.
order number for document A in section
XEI should read "390D" instead of
"3900". Similar changes should be
made ,in the ERIC order numbers for
these documents wherever they may
appear in the preamble, rule text, and
appendixes. _„
Electronic Submission of Comments
EPA'is encouraging people who
submit comments on the proposed
Guidance to provide one copy of their
comments in electronic format. Having
comments in electronic formatwill
facilitate analysis of the comments
received, and will help ensure
comments on specific topics.are
efficiently addressed EPA believes that
because a large majority ofcommenters
will-probably use microcomputers to,
prepare the comments, it may be
relatively easy for commenters to
prepare a diskette copy of the
comments. EPA would welcome
comments in any common diskette
format, but prefers 5.25" or 3.5""
diskettes compatible with WordPerfect
for DOS to reduce chances for incorrect
transfers from different formats to the
format EPA is likely to use.
Submission of a copy of the
comments in electronic format is ,
voluntary. EPA will give full :
consideration to comments whether or •
not they are accompanied by a copy in
electronic format. '- - ' " ,
Submission of comments in electronic
format does not eliminate the need for
commenters to provide an "original and
four copies of comments in hardcopy
format.
'To facilitate public review of the, •.
Guidance, diskette copies of the :
Guidance and selected supporting
materials are available from the
, addresses shown in section XIH of the
preamble. The NTIS order number is
PB-9'a-504-504. The ERIC order
number is 526D.
Dated: April 8,1993.
Tudor T.Davies,
Acting Assistant Administrator,
[FR Doc. 93-8659 Filed 4-15-93; 8:45 am]
BILUNG CODE 6580-01-P
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