United States
Environmental Protection Office of Water EPA 811-Z-92-002
Agency 4601 July 1992
&EPA 40 CFR, PARTS 141 and 142
NATIONAL PRIMARY DRINKING
REGULATIONS; SYNTHETIC
ORGANIC CHEMICALS AND
INORGANIC CHEMICALS
FINAL RULE
Recycled/Recyclable
Printed on paper that contains at least
50% post-consumer recycled fiber
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Friday
Julv 17. 1992
Part III
*
Environmental
Protection Agency
'40 CFR Parts 141 and 142
National Primary Drinking Water
Regulations; Synthetic Organic Chemicals
and inorganic Chemicals; Final Rule
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31776 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 141 and 142
tWH-FRL-4137-31
Drinking Water; National Primary
Drinking Water Regulations—Synthetic
Organic Chetnleat* and Inorganic
Chemicals; National Primary Drinking
Water Regulations Implementation
AGENCY: U.S. Environmental Protection
Agency (EPA).
ACTION; Final rule.
SUMMARY: By this document, EPA is
promulgating maximum contaminant
level goals (MCLGs) and National
Primary Drinking Water Regulations
(NPDWRs) for 18 synthetic organic
chemicals (SOCs) and 5 inorganic
che'micals (lOCs). The NPDWRs consist
of maximum contaminant levels (MCLs)
for the SOCs and lOCs. The NPDWRs
also include monitoring, reporting, and
public notification requirements for
these chemicals. Regulation of sulfate,
one of the contaminants in the proposed
rule, has been deferred. This document
includes the best available technology
(BAT) upon which the MCLs are based
and the BAT for the purpose of issuing
variances.
DATES: The effective date for revisions
and additions to 5§ 141.32.141.40.141.50
(except 141.50(b)(28)). 141.51141.61
(except 141.61(c)(28)), 141.62,142.16. and
142.62 is January 17,1994. The effective
date for revisions and additions to
§! 141.2,141.6,141.12.141.23.141.24.
141.50{b](26), 141.60.141.61(c}(26), and
141.89 is August 17.1992. In accordance
with 40 CFR 23.7. this regulation shall be
considered final Agency action for the
purposes of judicial review at 1 p.m..
Eastern time on July 31.1992.
ADDRESSES: Copies of the public
comments received, EPA responses, and.
all other supporting documents
(including references included in this
notice) are available for review at the
U.S. Environmental Protection Agency
(EPA). Drinking Water Docket 401 M
Street. SW.. Washington. DC 20480. For
access to the docket materials, call 202-
260-3027 between 9 a.m. and 3:30 p.m.
Any document referenced by an MRID
number is available by contacting Susan
Lawrence. Freedom of Information
Office. Office of Pesticide Programs, at
703-557-4454.'
Copies of health criteria, analytical
methods, and economic impact analysis
documents are available for A fee from
the National Technical Information
. Service (NTIS). U.S. Department of
Commerce. 5285 Port Royal Road.
Springfield. Virginia 22161. The toll-free
number is 800-338-4700. local: 703-487-
4650. Additionally, they can be reviewed
at the EPA regional offices listed below.
POM FURTHER INFORMATION CONTACT: .
Gregory Helms. Regulation Management
Branch. Drinking Water Standards
Division. Office of Ground Water and
Drinking Water (WH-550D). U.S.
Environmental Protection Agency. 401 M
Street. SW.. Washington. DC 20460. 202-
260-8049. or one of the EPA Regional
Office contacts listed below. General
information may also be obtained from
the EPA Drinking Water Hotline. Ca.'ers
within the United States may reach '.- .-
Safe Drinking Water Hotline at 800-^. '.-
4791. The Safe Drinking Water Hotlir i.
is open Monday through Friday.
excluding Federal holidays, from 8:30
a.m. to 4 p.m. Eastern Time.
EPA Regional Offices
I. JFK Federal Bldg.. Room 2203. One
Congress Street, llth floor. Boston. MA
02203. Phone: (617) 565-3810. Jerry Heaiey
II. 28 Federal Plaza. Room 824. New York. NY
10278. Phone: (212) 264-1800, Walter
Andrews
HI. 841 Chestnut Street. Philadelphia. PA
19107. Phone: (215) 597-9600. Dale Long
IV. 345 Courtland Street. N.E.. Atlanta. GA
30385. Phone: (404} 347-3633, Wayne
Aronson
V. 77 West Jackson Boulevard. Chicago, D.
60804. Phone: (312) 353-2000, Ed Walters
VI. 1445 Ross Avenue. Dallas. TX 75202.
Phone: (214) 655-7155. Tom Love
VII. 728 Minnesota Ave.. Kansas City. KS
66101. Phone: (913) 276-7032. Ralph
Langemeier
VIII. One Denver Place. 999 18th Street Suite
500. Denver. CO 80202-2468, Phone: (303)
293-1413. Patrick Crotty
IX. 75 Hawthorne Street. San Francisco. CA
94105, Phone-. (415) 744-1855, Steve
Pardieck
X. 1200 Sixth Avenue. Seattle. WA 96101.
Phone: (206) 553-1225. Jan Hasting*
SUPPLEMENTARY INFORMATION:
Table of Contents
Abbreviations Used in this Rule Li*t of
Tables
Table of Contents
I. Summary of Today's Action
II Background :
A. Statutory Authority
B. Regulatory History
C. Applicability . '..-.,
D. Public Comments on the Proposal' "f
III. Explanation of Today's Action
A. Establishment of MCLGs
1. How MCLGs are Developed
2. Occurrence and Relative Source Con-
tribution
3. Inorganic MCLGs
a. Antimony
b. Beryllium
. c. Cyanide •• .'••'•'
d. Nickel
e. Sulfate
f. Thallium
4. Organic MCLGs
a. Benzo(a)pyrene and other PAHs
b. Dalapon
c. Dichloromethane (Methylene chlo-
ride)
d. Di(2-ethylhexyl)adipate
e. Di(2-ethylhexyl)phthalate
f. Dinoseb
g. Diquat
h. Endothall
i. Glyphosate
j. Hexachlorocyclopentadiene (HEX)
k. Simazine
1.1.2.4-Trichlorobenzene
m. 1.1.2-Trichloroethane
n. 2.3.7.8-Tetrachlorodibenzo-p-dioxin
o. Endrin, hexachlorobenzene. oxamyl.
picloram
E Establishment of MCLs
1. Methodology for Determination of
MCLs
2. Inorganic Analytical Methods
a. Metals (antimony, beryllium, nickel
and thallium)
b. Anions (cyanide and sulfate)
c. Method Detection Limits and Practi-
cal Quantitation Levels
d. Inorganic Chemical Sample Preser-
vation. Container, and Holding
Times
3. Organic Analytical Methods
a. Method-Specific Comments
b. Responses to Comments Specific to
Method 1613 for Dioxin
c. Detection and Quantitation Levels:
Laboratory Performance Criteria
4. Laboratory Certification
5. Selection of Best Available Technolo-
gy
a. Inorganics
b. Synthetic Organic Contaminant
MCLs
6. Determination of MCLs
a. Inorganic Contaminant MCLs
b. Synthetic Organic Contaminant
MCLs
C. Compliance Monitoring Requirements
1. Introduction
2. Effective Date
3, Standard Monitoring Framework
a. Three-, Six-. Nine-Year Cycles
b. Base Monitoring Requirement!
c. Volatile Organic'Chemicals (VOCs)
d. Increased Monitoring
e. Decreased Monitoring
f. Vulnerability Assessments
g. Relation to the Wellhead Protection
(WHP) Program
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federal Rcsitter / Vol. 57. Mo. t3& /Friday. }uly 17. 1992 / Rules and Regidationa
h. Ground Water Policy
1. Initial and. Repeat Base Monitoring
4. Monitoring Frequenciei
a. Inorganics
(1) Initial and Repeat Base Require-
ments .
(2) Increased Monitoring
(3) Decreased Monitoring
b. Cyanide
c. Volatile Organic. Corrtaminantr
(VOCs)
(1) Initial and Repeat Base Require-
ments
(2) Increased Monitoring
(3) Decreased Monitoring
d. Synthetic Organic Chemicals
(SOCs)
(1) Initial and Repeat Base Require-
ments
(2) Increased Monitoring
(3) Decreased Monitoring
e. Sulfates
5. Other Issues
a. Compliance Determinations
b. Confirmation Samples
c. Compositing
d. Polynuclear Aromatic Hydrocar-
bons (PAHs)
D. Variances and Exemptions
1. Variances
2. Exemptions
3. Point-of-Use Devices. Bottled Water.
and Point-of-Entry Devices
4. Public Comments
E. Public Notice Requirements
1. General Comments
2. Contaminant-Specific Comments
F. Secondary MCL for Hexachlorocyclc-
pentadiene
C. State Implementation
1. Special State Primacy Requirements
2. State Recordkeeping Requirements
3. State Reporting Requirements
IV. Economic Analysis
A. Costs of the Final Rule
B. Comparison to Proposed Rule
1. Monitoring Requirements
2. Changes In MCLs
3. Changes in Occurrence Data
4. Changes in Unit Treatment Cost Esti-
mates
C. Cost to Systems
D. Cost to State Programs
V. Other Requirements
A. Regulatory Flexibility Analysis
B. Paperwork Reduction Act
C. Federalism Review
VI. References.
Abbreviation* U*od In This Rula
AA; Direct Aspiration Atomic Absorption
Spectroscopy
ACS: American Chemical Society
ADI: Acceptable Daily Intak*
- ASDWA; Association of State Drinking
Water Administrators
ASTM: American Society for Testing
Materials
BAT: Best Available Technology
• BTCA: Best Technology Generally Available
CRAVE: Oncer Risk Assessment
Verification Enterprise
CAAj Clean Air Act.
CAG: Cancer Assessment Group
CUR: Carbon Usage Rate
CWS: Community Water System
DWEL: Drinking Water Equivalent Level
EBCT: Empty Eled Contact Time
ELA: Economic Impact Analysis
EMSL Environmental Monitoring Systems
Laboratory (Cincinnati)
EPA: Environmental Protection Agency
FDA: Food and Drug Administration
Fit Federal Register •
GAC: Granular Activated Carbon
GFAA: Graphite Fumance Atomic
Absorption Spectroscopy
HPLC: High Pressure Liquid Chromatography
HSDB: Hazardous Substances Data Base
ICP-AES: Inductively Coupled Plasma-
Atomic Emission Spectroscopy
IE: Ion Exchange
IMDL: Inter-Laboratory Method Detection
Limit
IOC: Inorganic Chemical
IRIS: Integrated Risk Information System
LOAEL- Lowest-Observed-Adverse-Effect
Level
LOQ: Limit of Quantitation
MCAWW: Methods for Chemical Analysis of
Water and Wastes
MCL: Maximum Contaminant Level
(expressed as mg/1)1
MCLG: Maximum Contaminant Level Goal
MDL: Method Detection Limit
MF: Modifying, Factor
MGD: Million Gallons per Day
NAS: National Academy of Sciences
NCWS: Non-Community Water System
NIPDWR: National Interim Primary Drinking
Water Regulation
NOA: Notice of Availability
NOAEL: No-Observed-Adverse-Effect Level
NOEL: No-Ob:ierved-Effect Level
NPDES: National Pollution Discharge
Elimination System
NPDWR: National Primary Drinking Water
Regulation
NTIS: National Technical Information Service
NTNCWS: Non-Transient Non-Community
Water Syiitem
O&M: Operations & Maintenance
OPP: Office of Pesticide Programs
ORD: Office of Research and Development
OW: Office of Water
OX: Oxidation (Chlorine or Ozone)
PAC: Powdered Activated Carbon
PAHs: Polynuclear Aromatic Hydrocarbons
Pathco: Pathology Working Group
PE: Performance Evaluation
POE: Point-of-Entry Technologies
POU: Point-of-Use Technologies
PQU Practical Quantitation Level
FT A: Packed Tower Aeration
PWS: Public Water System
RCRA; Resource Conservation Recovery Act
RfC: Reference Concentration
RfD: Reference Dose (formerly termed
Acceptable Daily Intake (ADI))
R1A; Regulatory Impact Analysis
RMCL: Recommended Maximum
Contaminant Level
RO: Reverse Osmosis
RSC- Relative Source Cootributiin
SOW A: Safe Drinking Water Act or the
"Act" at amended in 19*8
SMCL: Secondary Maximum Contamir
Level
SMF: Standardized Monitoring Framev
SOC: Synthetic Organic Chemical
T&C: Technology & Costs
TEF: Toxic Equivalency Factors
TEM: Transmission Electron Microscop
TWS: Transient Non-Community Wate
System
UF: Uncertainty Factor- ;; • -
UIC: Underground Injection Control
USDA: U.S. Department of Agriculture
VOC: Volatile Organic Chemcial
WHP: Wellhead Protection
WHPA: Wellhead Protection Area
WS: Water Supply
11.000 micrograms (ng) = l milligram
List of Table*
Table 1—MCLGs and MCLs for Inorgai
Contaminants
Table 2—MCLGs and MCLs for Organi
Contaminants
Table 3—Best Available Technologies
Remove Inorganic Contaminants
Table 4—Best Available Technologies
Remove Synthetic Organic Contarr
Table 5—Compliance Monitoring
Requirements
Table 6—Analytical Methods for Inorg.
Chemicals
TaWe 7—Analytical Methods for Vola!
Organic Chemicals
Table 6—Analytical Methods for Pestic
SOCs
Table 9—Laboratory Certification Crite
Table 10—EPA's Three-Category Appr
for Establishing MCLGs
Table 11—Approved Methodology for
Inorganic Contaminants and Meth-
Detection Limits (MDLs)
Table 12—Inorganic Contaminant
Acceptance Limits and Practical
Quantitation Levels
Table 13—Inorganic Contaminant Sam)
Preservation. Container, and Holdi
Time Requirements
Table 14—Analytical Methods. DetectH
Limits. MDLs. PQLs. MCLs. and MC
for Organic Chemicals
Table 15—MCLs. PQLs and Acceptance
Limits Determined from Laboratory
Performance Studies
Table 18—Final BAT for Inorganic
Contaminants
Table 17—Proposed and Final BAT for
Organic Contaminants
Table l&—MCL Analysis for Category 1
Synthetic Organic Contaminants
Table 19—MCL Analysis for Category I
HI Synthetic Organic Contaminant!
Table 20—Section 1415 BAT for Inorgat
Compounds
Table 21—Section 1415 BAT for Organi.
Compound*
Table 22—Summary of Cost Estimate* I
Final Rul*
Table 23—Summary of Benefit* Estimat
Final Rule
Table 24—Comparison of Costs for Pro;
and Final Rule*
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JITTt
/ VoL 57, No. 138 / Friday. July 17. 1992 / Rufcs nod Regulation.
Tabk 25—Increased Coat of Compliance In
Selected System Size Categories
I. Summary of Todiy'i Action
TASL£ 1.—MCLGS AND MCLS FOR INORGANIC CONTAMINANTS
Cnsmcal
(1) Antimony ,„,„„,..,.. , .....,, ....... _,, ,
I2J 8a*yiMtv
i3) Cy«nm ,,. .,. _____ ._ ,..,
(4) N«l«tl™, .... , ,
(5) Sotlate ._,..
(6) Thallium _ ,._,_,
1 ProoOMd
j MCLG».
0.006
0004
0.2
0.1
0«f*rrod
Propoowo
• MOJ cfiicroettiar>« _..,„. _.,...__ „ „
1 .2.4'TncNorOfjen.iene .„._._._,„,., _ .
1.1J2*Tr>criioroetiw>e ._
Dm Don ... ..._,,
Dtnoub
fVy^it
E«x3otha)f . ........... .
Enorm , „...._„_.... . ,
Glypr«saie
Onamyt (Vydatfl)
P*c*e)ryl}pMhalaIt
Hexacr*5rc*en»r>e,
2.3.7 J-TCOO (Ooan) .__
1
'
1
' "i
'" """]
. . |
.. _ . j
... — .j
MCLGa (mg/
7orf*
0.003
0 002
0 5
2wo
0.05
Final
MCLGo (mg/
0
0.003
2en»
0.05
MCU (mg/
0.005
0.009
0.005
0.2
0.007
0.02
0.1
0.7
0^
0.5
0.001
aoci
0.05 '
Final
MCU (mg/
I)
0.005
0.07
0.005
0,2
•3.007
0.02
0.1
0.002
0.7
0.2
0.5
0.004
0.0002
0.006
a 001
0.05
TA8t£ 3—BasT AVAILABLE TECHNOLOG^S To REMOVE INORGANIC CONTAMINANTS
Irvorgartc contaminant
Bwyiixxn.., _.
Cysmoe.. — ...
N(ckei,..._....__._.,..
TIMWiom ,™......» _„ __
Activated
alumn*
X
X
CoagLirt.cn/
fcraecx.
X
X
B«*t <
Urn*
»or>anne>
X
^
va4*M« toc.vx>k
ion ochcng*
X
X
X
5g«*
Reverse
osnosi*
X
X
Chtooo*
oxidation
:
Bectrodaty
«•
' Not 1415 BAT «or unaf ffOtnt for variance* ortes* treatment • curenOy n ptac*.
TABLE *-!BEST AVAILABLE TECHNOLOGIES To REMOVE SYNTHETIC ORGANIC COWTAMJNAKTS
Chenwal
VOCa:
OcMoromemane , ..
1i.4.Tnef>loro<>weeo»
1.1.2-Tnchkxoeiftane _ .. _.. '•
PMCOEtee: . .
DA^An^^ . *~
a««-h .
Diouat,. _
FrWrfhrf , ,
crtorin... tt lrt
Glyprvouta.. „ "
Oxim/t (Vyct«te)__ ._._.. . . _._
ftcloram ™™7IL'_Z !_ 1_
GAC'
j(
X
X
X
X
. X
_
X
PTA»
ox«
X
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Federal Register / VoL 57, No. 138 / Friday. July 17, 1992 / Rules and Regulations
31779
TABLE 4—BEST AVAILABLE TECHNOLOGIES To REMOVE SYNTHETIC ORGANIC CONTAMINANTS—Continued
Chemical
GAC'
PTA«
OX'
Omer Organic Contammarits:
237 8-TCDD (Dtoxin) ..."
X
X
X
x
. X
X
X
X
X
' GAC = Granular activated carbon.
» PTA = Pacned tower aeration.
•• OX = Oxidation (Chlorine or Ozone).
TABLE 5.—COMPLIANCE MONITORING REQUIREMENTS *
Contaminant
8as« requirement
Ground water
Surface water
Trigger that increase* monitoring
Waivers'
4 inorgarxs 1 Sample/3 years... Annual sample MCL— Yes. based on analytical result* of 3
rounds.
1 Sample/9 years after 3 samples < MCL
Cyarwde _ 1 Sample/3 years _ Annual sample..: >MCt , '. Yes. based on vulnerability assessment.
1 Sample/9 years after 3 sample* CAL METHODS FOR
PESTJCtDES/SOCS
EPA rrwtftods
505
506
507
soe
515.1
531.1
1613
547
54*
549
550/560,1
Contamirtants
Endrin.
Simazine.
Di (2-e4hytt^e3ryf) adip*i*.
Di (2-ethy«>*xy() prtlTiaiat*.
Simazin*.
Endhn.
Datapon,
Dinoeeb.
Picloram.
Oitamvl (V/d***).
2.3.73-TCOO (Otoar^.
GrfphOMtil.
EndoJh*.
DiquK.
Benzo (a) pvn»n*.
TABLE 8.— ANALYTICAL METHODS FOR
PESTtctOES/SOCs— Continued
EPA 'method*
•525.1
•Contaminants
Benzo(a) pyren*.
DI (2-ethyfhexyO aolpate.
01 <2-ethylhe*yf) phthalat*.
Endhn.
Hexachlorobenzen*.
HexachkxocyclopentarJeri*.
Simazin*,
' MeO»a525.1maY be
mfofrnstiofv.
TABLE 9.— LABORAT
ORTT
/OCt
Antimony_
BeryaSum._
Cyanide
Nick*
The*um
VOCK
SOCf
At other SOC*
used i adequate sensrtivi-
Section 1KB for addttonal
ORY CERTIFICATJON
ER1A
±30% £ 0.006 mg/L
±15% S 0.001 mg/L
±25% £ 0.1 mg/L
±15% £ 0.01 mg/t
±30% £ 0.002 mg/l
±20% £ 0.01 rng/t
±40% < 0.01 mg/L
±30%.
2 xandert de*«*«on«
band on study
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3178ft
/ VoL 57. No. 138 / Friday. July 17. IflCZ / Raks and Regulation*
II. Background
A. Statutory Authority
These regulations are among a
continuing aeries of rules mandated by
the 1988 Amendments to the Safe
Drinking Water Act. As this final rule
demonstrates. EPA is committed to
effective implementation of the laws .
established by Congress-It should be
noted that EPA's development and
promulgation of these rules is now being
coordinated with a number of other EPA
activities intended to ensure protection
of public health while responsibly
addressing the economic challenge of
the ever-growing list of regulatory
requirements on States and water
systems. To the extent that the results of
this coordination call for change in the
law. we will make that known to the
Congress. It is a commitment of EPA.
however, to understand where
legitimate local implementation
concerns exist.
EPA is working with a recently
convened Governors' Forum on
Environmental Management that is
reviewing means to ensure health
protection while balancing the need for
State regulatory flexibility to address
the States' highest priorities with
available resources. EPA'i
Environmental Financial Advisory
Board Is developing alternative
financing mechanisms with particular
attention on small community concerns.
In addition. EPA is in the third year of
an initiative to identify and promote
low-cost solutions to drinking water
protection. These include consolidation
of water systems to spread costs over a
larger consumer base: pooling of several
systems' water samples to reduce
monitoring cost and low-cost treatment
technologies that can cut water bills in
very small water systems to as much as
one-half what might arise with
traditional engineering solutions.
In addition. EPA is considering greater
reliance on risk-based priority-setting
within State compliance programs. That
approach would focus limited State and
Federal resources on those elements of
the public water supply supervision
program having the greatest potential
for reducing risk and promoting public
health protection. Again, EPA would
only take action in this area to the
extent consistent with law.
The Safe Drinking Water Act (SDWA
or "the Act"), as amended in 1988 (Pub.
L 99-339,100 Stat 642}, requires EPA to
publish "maximum contaminant level
goals" [MCLGs] for contsmininti which,
in the Judgment of the Administrator,
"may have any adverse effect on the
health of person* end which {are]
known or anticipated to occur in public
water systems" (section 1412(bK3MA)).
MCLGs are to be set at a level at which
"no known or anticipated adverse
effects on the health of persons occur
and which allows an adequate margin of
safety" (section 1412(b)(4)).
At the same time EPA publishes an
MCLG. which is a non-enforceable
health goal, it must also promulgate •••>'•'
National Primary Drinking Water
Regulation (NPDWR) which includes
either (1) a maximum contaminant level
(MCL). or (2) a required treatment
technique (section 1401(1), 1412(a)(3).
and 1412(b)(7)(A)). A treatment
technique may be set only if it is not
"economically or technologically
feasible" to ascertain the level of a
contaminant (Sections 1401(1) and
1412(b)(7)(A)). An MCL must be set as
close to the MCLG as feasible (section
1412(b)(4)). Under the Act. "feasible"
means "feasible with the use of the best
technology, treatment techniques and
other means which the Administrator
finds, after examination for efficacy
under field conditions and not solely
under laboratory conditions (taking cost
into consideration)" (section 1412(b)(5}).
In setting MCLs. EPA considers the cost
of treatment technology to large public
water systems with relatively clean
source water supplies (132 Cong. Rec.
S6287 (daily ed.. May 21.1986)).1 Each
NPDWR that establishes an MCL must
list the best available technology,
treatment techniques, and other means
that are feasible for meeting the MCL
(BAT) (section 1412(b)(6)). NPDWRs
include monitoring, analytical and
quality assurance requirements,
specifically, "criteria and procedures to
assure a supply of drinking water which
dependably complies with such
maximum contaminant levels * * * "
(section 1401(1)(D)}. Section 1445 also
authorizes EPA to promulgate
monitoring requirements.
Section 1414{c) requires each owner or
operator of a public water system to
give notice to persons served by it of (1)
any failure to comply with « maximum
contaminant level, treatment technique,
or testing procedure required by a
NPDWR: (2) any failure to comply with
any monitoring required pursuant to
section 1445 of the Act; (3} the existence
of a variance or exemption; and (4) any
failure to comply with the requirements
of any schedule prescribed pursuant to «
variance or exemption.
Under the 1986 Amendments to the
SDWA, EPA was to complete the
promulgation of NPDWRa for 83 listed
contaminants, in three phases, by fooe
19,1989. After 1969, an additional 23
1 EPA
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Federal
/ VoL 57, No. 13* / Friday, July 17. 199* / Rules and
31781
standards is specifically required und«r
the SDWA for 22 of the 23 contaminants
in today's rule [see SDWA section
1412(b](l), 42 U.S.C. 300g-l(bKl)].
Hexachlorobenzene. although not on the
statutory list of contaminants to be
regulated, is being regulated because it
has.been found in drinking, water and-
may cause adverse human health
effects.
C. Applicability
The MCLs promulgated by today's
rule apply to all community and non-
transient non-community PWS.
"U. Public Comments on the Proposal
EPA requested comments on all
aspects of the July 25,1990 proposal A
summary of the major comments and the
Agency's response to the issues raised
are presented in the following section.
The Agency's detailed response to the
comments received are presented in the
document "Response to Comments
Received on the Proposed Requirements
for 24 Contaminants of July 25,1990 and
Notice of Availability of November 29,
1991," which is in the public docket for
this rule.
EPA received approximately 138
comments on the proposed MCLGs and
MCLs in the July 1990 proposal. These
comments represented the views of 66
industrial/commercial groups, 25 State
governments, 36 local governments and
public water systems, 2 public interest
groups, 3 Federal agencies, as well as
. comments from individual citizens and
academic interests.
EPA held a public hearing on the
proposed rule September 25,1990 in
Washington, DC. Six individuals
representing three organizations made
oral presentations at the public bearing.
A transcript of the hearing is available
in the docket [USEPA. 1990J].
EPA published a Notice of
Availability (NOA) on November 29.
1991 for public review and comment on
new information received by the Agency
and analyses of the information, which
was being considered in establishing
final regulations for these contaminants.
EPA received approximately 34
comments on the NOA. Thete comments
represented the views of 14 industrial/
commercial groups, 10 State
- governments, and 10 local governments
and public water systems.
' m. Explanation of Today's Action
A. Establishment of MCLGs
Most of the MCLGs promulgated
today are at the same level as proposed
in July 1990, However, the MCLGt far
antimony, beryllium, skruudne, di(2-
ethylhexyljadipate and 1.2,4-
trichlorobenzene are different from
those proposed in that notice. Changes
result from public comments and/or new
information received by the Agency. The
change in the MCLG for antimony is due
to a revaluation of the relative source
contribution based on public comments.
The change in UM MCXG forberyllium is .
due to « reevataatioa of its •
categorization for setting the MCLG (i.e..
EPA revised its classification from
Category I to Category II based on
public comments and revaluation of the
data). The MCLGs for simazine, di(2-
ethylhexyl)adipate arid 1.2.4-
trichlorobenzene changed because new
health information became available for
these three compounds since the July
1990 proposal. The new health data and
other information pertinent to this rule
was made available to the public for
review and comment in the November
1991 NOA {56 FR 60949}. A full
explanation of these changes is included
below in the sections for each specific
contaminant. The draft health criteria
documents prepared in support of the
proposed niles have all been finalized
and placed in the public docket and
through NTIS, with the exception of
documents for dioxin and sulfate. Dioxin
is being regulated bailed on the
information in the draft criteria
document pending Agency review of
dioxin health effects. Regulation of
sulfate has been deferred.
Most of the MCLs promulgated today
are at the same level as proposed in
July. 1990. The MCL for thallium, for
which options of 0.002 mg/1 and 0.001
mg/1 were proposed, is being finjli**d
as 0.002 mg/L Based on additional
analytic chemistry data presented in die
NOA. the proposed dioxin MCL of
SxlQ-'mg/l is being reduced to 3xlO~*
mg/1 in this final rule. The MCLG and
MCL for sulfate are being deferred
pending further study. The fnstificanon
for this action is discussed in section
IH.B.5 of this notice. Sulfate will b*
addressed in a future action.
In today's rule. EPA is responding to
the major issues raised by the public in
reference to the July 1990 proposal [55
FR 30370] and the November 1991 NOA
[56 FR 60949]. For EPA's complete
response to all issues raised in
comments on both the July 1990 and
November 1991 notic«s, EPA refers the
reader to the Comment/Response
Document found in the Phase V docket
'[USEPA, 1992a],
1. How MCLGs Are Developed
MCLGs are set at concentration levels
at which no known or anticipated
adverse health effects occur, allowing
for an adequate margin of safety.
Establishment of an MCLG for each
specific contaminant depends on the
evidence of carcinogenitity from
drinking water exposure or the Agency's
reference do*e (RID) based on
noncarcinogeriic data.
The cancer classification for a specific
chemical and the reference dose are
adopted by two. different Agency group*.
Decisions on cancer classifications are
made by the Cancer Risk Assessment
Verification Endeavor (CRAVE) Work
Group, which is composed of
representatives of various EPA program
offices. Decisions on EPA RfDs (using
non-cancer endpoints only) are made
through the Agency RfD/RfC work
group, also composed of representatives
of various EPA program offices.
Decisions by CRAVE and the RfD/RfC
groups represent consensus on risk
assessments for the Agency and can be
used by the respective regulatory
programs as the basis for regulatory
decisions. Summaries of the decisions
by these two groups are published in the
Agency's Integrated Risk Information
System (IRIS). This system can be
accessed by the public by contacting
Mike McLaughlin of DIALCOM, Inc. at
202-488-0550.
The RfO (expressed in mg/kg/day) is
aa estimate, with uncertainty spanning
perhaps an order of magnitude, of a
daily exposure to the human population
sensitive subgroups) that is
likely to be without an appreciable risk
of deleterious health effects during a
lifetime. The RfD is derived from a no-
or lowest-observed-adverse-effect level
(called a NOAEL or LOAEL.
respectively) that has been identified
frora a sobchronic or chronic scientific
study of humans or animals. The
NOAEL or LOAEL ts then dirid«d by
uncertainty factors) to derive the RfD.
Uncertainty factors are u«ed in order
to estimate the comparable "no-effect"
level for a larger heterogeneous human
population. The use of uncertainty
factors accounts for intra- and inter-
spedet variability, the small number of
animals tested compared to the size of
the population, sensitive subpopulations
and the possibility of synergistic action
between chemicals (see 52 FR 25600 for
further discussion OB the use of
uncertainty factors).
The us* of an uncertainty factor (UF)
is important in the derivation of the RfD.
EPA has established certain guidelines
(shown below) fo determine how to
apply uncertainty factors when
establishing an RID [USEPA. 1966).
Uncazteimry Factors (UFsi
• Use a 1- to W-feW factor when
extrapolating front vtHd experimental
from ctadies osing prolonged
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31782 Federal RegUtw / Vol 57. No. 138 / Friday. July 17. 1992 / Rulea and Regulations
exposure to average healthy humans.
This factor is intended to account for the
variation in sensitivity among the
members of the human population.
• Use an additional 10-fold factor
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. This factor is intended to
account for the uncertainty in
extrapolating animal data to the case of
humans.
• Use an additional 10-fold factor
when extrapolating from less than
chronic results on experimental animals
where there are no useful long-term
human data. This factor is intended to
account for the uncertainty in
extrapolating from less than chronic
NOAELs to chronic NOAELs.
• Use an additional 10-fold factor
when denving a RfD from a LOAEL
instead of a NOAEL. This factor is
intended to account for the uncertainty
in extrapolating from LOAELs to
NOAELs.
An additional uncertainty factor may
be used according to scientific judgment
when justified.,..
• Use professional judgment to
determine another uncertainty factor
(alao called a modifying factor. MF) that
is greater than zero and less than or
equal to 10. The magnitude of the MF
depends upon the professional
assessment of scientific uncertainties of
the study and data base not explicitly
treated above. e.g., the completeness of
the overall data base and the number of
species tested. The default value for the
MFisl.
From the RfD, a drinking water
equivalent level fDWEL) is calculated.
The DWEL represents the drinking
water lifetime exposure at which
adverse health effects are not expected
to occur over a lifetime. The DWEL is
calculated by multiplying the RfD by an
assumed adult body weight (generally 70
kg) and then dividing by an average
daily water consumption of 2 liters per
day [NA&.1977], The DWEL assumes" • •
the total daily exposure to a substance
is from drinking water exposure. The
MCLG is determined by multiplying the
DWEL by the percentage of the total
daily exposure expected to be
contributed by drinking water, called
the relative source contribution.
Generally, EPA assumes that the
relative source contribution form
drinking water is 20 percent of the total
exposure, unless other exposure data for
the chemical are available [see 54 FR
22089 and 56 FR 3535]. The relative
source contribution may be as high as 80
percent. The calculation below
expresses the derivation of the MCLG:
RfD
DWEL -
NOAEL or LOAEL
uncertainty factor(s)
RfD x body weight
daily water consumption in I/day
MCLG - DWEL x drinking water contribution
(rounded to one significant figure)
ttg/kg body weight/day (1)
ng/1 (2)
- mg/1 (3)
For chemicals suspected to be
carcinogenic to humans, the assessment
for non-threshold toxicants consists of
the weight of evidence of
carcinogenicity in humans, using
bioassays in animals and human
epidemiological studies as well as
information that provides indirect
evidence (i.e., mutagenicity and other
short-term test results). The objectives
of the assessment are (1) to determine
the level or strength of evidence that the
substance is a human or animal
carcinogen and (2) to provide an
upperbound estimate of the possible risk
of human exposure to the substance in
drinking water. A summary of EPA's
general carcinogen classification
scheme is (USEPA. 1986]:
Group A—Human carcinogen based
on sufficient evidence from
epidemiological studio*.
Croup Bl—-Probable human
carcinogen based on limited evidence of
carcinogenicity in human*. ;
Group A?—Probable, human .
carcinogen based on a combination of
sufficient evidence in animals and
inadequate data in humans.
Group C—Possible human carcinogen
based on limited evidence of
carcinogenicity in animals in the
absence of human data.
Group D—Not classifiable based on
lack of data or inadequate evidence of
carcinogenkity from animal dat*.
Group E—No evidence of -
carcinogenicity for humans (no evidence •
for carcinogenicity in at least two
adequate animal testa in different
species or in both epidemiological and
animal studies).
EPA follows a three-category
approach in developing MCLG* for
drinking water contaminant* (Table 10).
TABLE 10.—EPA'a THREE-CATEGORY
APPROACH FOR ESTABLISHING MCLGs
C«t«gory
Evidtne* of
*yvi*
Strong «vid«oco
ofwmtenc*,
pottncyand
•XpOttflL
UmiUd «vti*nc*
cexwdtring w«ght
of «vi4tnc*.
ptwmecokinetic*.
potency and
•xpoaure.
Inacfcqutt* or no
MCLG
•pproAch
Zero.
RfD approach
ufetjr margn
oil to to or
W» 10 W»
Each chemical 1* evaluated for
evidence of caranegenicity via
ingestioB. For volatile contaminant*,
inhalation data should also be
considered. EPA take* Into.
consideration the overall weight of '
evidence for carcinogenicity,
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Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rulei and Regulations
91763
pharmacokinetics. potency and
exposure.
EPA's policy is to set MCLGs for
Category I chemicals at zero. The MCLG
for Category II contaminants is
calculated by using the RfD approach
with an added margin of safety to
account for possible cancer effects. If
adequate data are not available to •. .
calculate an RfD, the MCLG is based on
a cancer risk range of 10"5 to 10"*.
MCLGs for Category III contaminants
: are calculated using the RfD/DWEL
approach.
The MCLG for Category I
contaminants is set at zero because it is
assumed, in the absence of other data,
that there is no known threshold for
carcinogenicity. Category I
contaminants are those for which EPA
has determined that there is strong
evidence of carcinogenicity from
drinking water. In the absence of other
data (e.g.. oral) on the potential cancer
risk from drinking water ingestion.
chemicals classified as Group A or B
carcinogens are generally placed in
Category I.
Category II contaminants include
those contaminants which EPA has
determined that there is limited
evidence of carcinogenicity from
drinking water considering weight of
evidence, pharmacokinetics, potency
and exposure. In the absence of
ingestion data, chemicals classified by
the Agency as'Group C chemicals are
generally placed in Category II. For
Category II contaminants, two
approaches are used to set the MCLG:
Either (1) setting the MCLG based upon
noncarcinogenic endpoints of toxicity
(the RfD) then applying an additional
safety factor of 1 to 10. or (2) setting the
MCLG based upon a theoretical lifetime
excess cancer risk range of 10"5 to 10"*
using a conservative mathematical
extrapolation model. EPA generally uses
the first approach: however, the second
approach is used when valid
noncarcinogenic data are not available
to calculate an RfD and adequate
experimental data are available to
quantify the cancer risk.
EPA requested comment on tha
appropriateness of these approaches for
establishing MCLG* in the July 25.1990
proposal (see 55 FR 30404-05). Two
comments were received on this issue.
One commenter stated.that the MCLGs
and the MCLs should be set at level*
able to protect against carcinogenic risk.
The other commenter stated that Group
C contaminants are not suitable for
evaluation by EPA's cancer risk
; assessment process, tnd supported •
EPA's use of non-cafcinogqsic data for -
establishing the MCLG foe these .
chemicals, EPA believes that the present
approach for Category II contaminants
is protective of non-cancer effects as
well as potential carcinogenic risk.
Therefore, because adequate non-
carcinogenic data are available, the
MCLGs promulgated today for Category
II contaminants (beryllium. di(2-
ethylhexyljadipate. simazine and 1,1.2-
trichloroethane) us« the first optioru Lei.
they are based on the RfD with an
application of an additional safety
factor.
Category III contaminants include
those contaminants for which there is
inadequate evidence of carcinogenicity
from drinking water. If there is no
additional information to consider.
contaminants classified as Group D or E
chemicals are generally placed in
Category III. For these contaminants, the
MCLG is established using the RfD
approach.
2. Occurrence and Relative Source
Contribution
Most of the comments received on
occurrence/exposure and relative .
source contribution (RSC) were related
to current EPA policy. The Agency has
addressed many of tile questions raised
by these commenters in the Comment
Response Document for this rule. Below
is a summary of the major issues raised
and EPA's response.
EPA received some comments
questioning the need to regulate a
chemical if there are little occurrence
data available, if the chemical occurs
infrequently or at low levels, or if the
RSC is below 20 percent. The Agency
has the statutory mandate, under
Section 1412 of the SDWA, to regulate
contaminants "which are known or
anticipated to occur in public water
systems." The Agency believes that the
contaminants in today's rulemaking •
have either been found or potentially
may occur in public water supplies and
that they may pose a health risk to
consumers. Also, development of
drinking water standards is specifically
required under the Safe Drinking Water
Act (SDWA) for 22 of the 23
contaminants in today's rule (see SDWA
Section 1412(b)(l), 42 U.S.C. 300g-
Several commenters questioned why
EPA was regulating hexachlorobenzene,
since it is not on the list of 83
contaminants nor on the Drinking Water
Priority List (DWPL),,
Hexachlorobenzene. although neither on
the statutory list of contaminants to be
regulated nor on tha DWPL, is being
regulated because it has b««n found in
drinking water and may cause adverse
human health effectii.
As described in tht background
occurrence document for
hexachlorobenzene {USEPA, 1989bj. it
has been widely detected in water
albeit at low levels. Of 1.053
observations of ground water in
STORET. 1.028 samples had detectible
(although not quantifiable) levels of
hexachlorobenzene. In surface water
STORET samples. 48 of 54 samples ha I
. detectible (although not quantifiable}" -.-
levels of hexachlorobenzene. The
potential for hexachlorobenzene
occurrence in public water supplies is
corroborated by more recent
information reported in EPA's "National
Survey of Pesticides in Drinking Water
Wells" {USEPA. 1990i], which detected
hexachlorobenzene in several samples
and projected that 470 PWS wells (range
61-1.630 wells) may have detectible
levels (the minimum reporting limit for
the NPS was 0.060 jig/1). EPA therefore
believes that although levels may be
low. there is ample evidence to conclude
that hexachlorobenzene is known or
anticipated to occur in public water
systems as required by the SDWA.
Several comments were received on
the current policy related to the use of a
20 percent floor and 80 percent ceiling
for the RSC in setting the MCLG. Some
commenters objected to using a 20
percent floor and 80 percent ceiling for
the RSC when actual data are available
and suggested percent contributions
above or below these levels. Others
suggested using an RSC of less than 20
percent if available data indicate a
drinking water contribution below this
percentage, assuming 100 percent
contribution from drinking water in the
absence of data, and assuming 50
percent contribution from inorganics
and some pesticides in the absence of
data.
The Agency continues to believe the
20 percent floor and 80 percent ceiling
are prudent and protective of public
health. The 20 percent floor represents a
level below which additional
incremental protection is negligible. In
addition, below 20 percent RSC from
water is a dear indication that control
of other more contaminated media will
result in a significantly greater reduction
in exposure. EPA believes the 80 percent
ceiling is required because it ensures
that the MCLG will be low enough to
provide adequate protection for those
individuals whose total exposure to a
contaminant is higher than indicated by
available data. This approach, in effect
results In a slightly lower MCLG and
increases the margin of safety. EPA
utilizes the actual percentage when , •
adequate exposure "ffata exist and
indicate ah RSC- between 20 and 80
percent, but wheri data are not
adequate, 20 percent Is generally used
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31784 Faderal R«gbter / Vot. 57. No. 138 / Friday. July 17. 1992 / Rule« and Regulations
as a default value that is protective of
public health. In addition, the Agency
does .not believe that assuming a SO
percent RSC is appropriate for
inorganics or pesticides in the absence
of data, as suggested by a comrhenter. In
fact, there have been numerous
inorganics (such as lead or mercury) and
pesticide* regulated by EPA in public... ••
drinking water supples for which the
available data from all sources indicate
that drinking water likely contributes
less than SO percent to total exposure
and. in some cases, less than 20 percent.
Therefore, there is no basis for
automatically assuming 50 percent from
drinking water when data are not
available.
There were three chemical-specific
issues regarding setting the RSC. One
RSC issue concerned cyanide. Several
commenters suggested the use of an 80
to 100 percent RSC because they felt
that drinking water represents
essentially all exposure. The Agency
has decided to use a 20 percent RSC for
this contaminant because the available
data on dietary exposure are
inadequate, and the Agency therefore
could not adequately characterize
overall exposure to cyanide.
Another commenter claimed that the
Agency misinterpreted a USDA study
(Miller-Ihli and Wolf, 1966] on the
dietary intake, and that EPA should
have used more appropriate data
regarding intake of nickel from food and
air to calculate the MCLG. The Agency
agrees that the study relied upon in the
proposed rule was inappropriate for
calculating dietary exposure for nickel
because that study analyzed foods that
were freeze-dried, which resulted in
elevated nickel concentrations (higher
than one would determine in fresh
foods). The Agency has recalculated the '
dietary contribution using an FDA diet
study by Pennington and Jones (1987).
Unlike the Miller-Ihli and Wolf study.
which involved an analysis of freeze-
dried foods, the Pennington Diet Study
program [Pennington and Jones. 1967] is
appropriate for estimating overall
exposure. The revised calculation
indicates again that drinking water
contributes less than 20 percent of th«
daily intake. Therefore, the Agency is
using 20 percent as the RSC in the
calculation of the final MCLG for nickel
following present policy of a 20 percent
floor. Two commenten on the NOA
urged EPA to revise the RSC for nickel
and base a new RSC on analysis of
actual data, as wa» done for antimony..
As discussed above, EPA has done thi* .
and believes the available data, in. . .'
conjunction with EPA's policy, on RSC
supports the use of the 20 percent'vaJu*.
The third issue ia related to EPA's
proposal to use a 20 percent RSC for
antimony as a default value. The
Agency agrees with the commenter that
there is information available on which
the RSC can appropriately be based.
The Agency has decided to use an
occurrence study by Grealhouse and
Craun (1978^ andhu estimated .typical •'
levels of 2 jig/1 antimony in drinking
water. This study was chosen due to its
large sampling base and
representativeness of antimony levels
nationwide. The Agency has also
recalculated the dietary intake of
antimony using a different food study by
Cunningham and Stroube (1987). The
dietary contribution of 4.7 fig/day of
antimony calculated from this study is
lower than previously estimation. The
Cunningham and Stroube report was
judged adequate for determining the
overall exposure estimation. This study,
conducted by the FDA. uses the
methodology of their Total Diet Study
program [Cunningham and Stroube.
1967). By using an inhalation
contribution of 0.7 jig/day and the 4.7
jig/day from the diet along with a mean
drinking water contribution of 2 ng/1 (or
4 jig/day), the resulting RSC is 40
percent (rounded from 42.6 percent). Th«
NOA requested comment on revision of
the antimony RSC. and several
commenters supported the proposed
revision. The final MCLG for antimony
reflects this change in the RSC
The Agency refers readers to the
Comment Response Document [USEPA.
1992a] for additional detailed
information on the issues discussed
above, and for a discussion of other
exposure/RSC related comments raised-
during the public comment period.
3. Inorganic MCLGs
a. Antimony. EPA proposed an MCLG
of 0.003 mg/1 for antimony in the July 25,
1990 proposal [55 FR 3O377J. Antimony
has been classified in Group D
(inadequate evidence of cardnogenioty
In humans) by EPA guideline*. The
proposed MCLG was derived from a
DWEL of 0.015 mg/L applying a 20
percent contribution from drinking
water. The MCLG was based upon a
LOAEL of 0.43 rag/kg/day for
noncarcinogenic effects in a lifetime
drinking water study in rats [Schroedcr
et aL. 1970). An'uncertainty factor of
1,000 was applied to the LOAEL derived
from a lifetime animal study (which i* in.
accordance with MAS/EPA guidelines).
No new toxicological daia that would
change the conclusion* presented in the .
July 25,1990 proposal have became
available since its publication.. \
However, the Agency has revised Us
calculation of the-rtlativesvatw
contribution for antimony after
reconsidering the occurrence/exposure
data, as discussed in the "Relative
Source Contribution" section above.
Based on this reassessment of the
available occurrence/exposure data, the
final RSC for antimony has been set at
40 percent. This change in the RSG s ••"•••: •''
results in a doubling of the final MCLC
from 0.003 to 0.006 mg/1 for antimony.
Public Comments: In response to the
July 25.1990 notice, one individual or
organization commented on the MCLG
proposal for antimony. The commenter
indicated that an online computer
search of the Hazardous Substances
Data Base (rfSDB) showed that
antimony causes marked weight loss.
hair loss, dry scaly akin, eosinophilia.
m'yocardia! failure, vomiting, diarrhea
and stomatitis in animals orally
exposed.
EPA Response: EPA agrees with the
commenter that antimony causes the
above mentioned effects when used in
high doses in animal tests. These effects
were discussed in the Health Criteria
Document for antimony supporting the
July 1990 proposal [USEPA. 19904
finalized as USEPA. 1992b]. However.
the effects reported in the July 1990
notice are effects associated with the
critical endpoint of toxicity used to
establish the lowesl-observed-adverse-
effect level (LOAEL) for antimony. The
effects described by the commenter are
acute efleets noted at much higher dose
levels than the dose causing the critical
effects described in the July 1990 notice.
Since the critical effects are the basis of
the DWEL and MCLG calculations for
antimony, only these effects were
discussed in the July 1990 proposal.
Detailed descriptions of antimony
toxicity at different dose levels and in
different animal species are documented
in the Antimony Health Criteria
Document prepared in support of the
July 1990 notice [USEPA. 19804
finalized in USEPA. 1992f]. This
document is available in the EPA Public
Docket. Office of Water. Based on the
available toxicological information and
on the relative source contribution -
reassessment, the Agency is
promulgating today an MCLG of 0006
mg/1 foe antimony.
b. Beryllium. EPA followed a
Category I approach for beryllium and
proposed an MCLG of zero for beryllium
in drinking water (55 FR 30378) based on
the evidence of carcinogenic potential
from drinking water. The Agency
requested comment on. setting the MCLC
at zero for beryllium given that th« oral .
expocurs- biotuayt on not adequate to
conclusively demonstrata a doa«-
relationship, Beryllium Is
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Federal Register / Vol 57. No, 139 /Friday. July 17. 1992 / Rule» and RegulatJona 31785
classified in Group B2, probable human
carcinogen, based on the positive
carcinogenic findings in several animal
species exposed to beryllium by
inhalation and injection. In addition.
available data indicate tumor induction
by several beryllium compounds and
genotoxic.activity in animal .studies. .
Since the dose-response evidence of
carcinogenicity specifically by ingestion
is limited, the Agency requested public
comments on setting the MCLG of
beryllium at zero.
Public Comments: Eleven commenters
responded to the beryllium proposal.
One significant area of comment in
response to the proposal deals with the
carcinogenicity of beryllium via the oral
route of exposure. The commenters
disagreed with the Agency on the
classification of beryllium in Group B2.
The commenters stated that cancer
studies performed with beryllium sulfate
in drinking water [Schroeder et al.. 1970]
or in feed [Morgareidge. 1977] are
inadequate because the tumors
observed in these studies were
statistically not significant when
compared with those in controls. One
commenter suggested that since
statistical significance was not observed
in these studies, beryllium should be
classified as a Group C carcinogen and
the MCLG should be recalculated using
the options for Group C compounds. The
commenter stated that the Agency has
been inconsistent in its proposed
regulation for beryllium in drinking
water because MCLGs have been set at
non-zero levels for nickel, chromium.
cadmium, antimony and asbestos, which
are classified by the Agency in Group A
or B, via inhalation but in Group C or D
by the oral route.
In addition, one commenter sent two
additional studies of beryllium toxicity
to EPA during the comment period for
the November 29.1991 NOA.
EPA Response: EPA establishei •
MCLGs for drinking water contaminants
by placing them in three categories, a»
discussed above. With regard to the oral
carcinogenicity of beryllium, EPA hai
reconsidered the data and agrees with
the comments regarding the oral
beryllium studies in that the induction of
tumors was statistically not significant
when compared with the controls.
:; However, the Agency believes that
these studies show a suggestive
tumorigenic response which are
r. consistent with the hazard seen In other
- portions of the beryllium data bas«. In
the July 1990 proposal the Agency
indicated that these studies were limited
In their usefulness to evaluate .
carcinogenic potential in snlmals
becaus«-the Schroeder et «L study (1970)
used only one dose, and the
Morgareidge study did not reflect a
traditional dose-response relationship.
In the Morgareidge study, there was an
increase in reticulocyte tumors in rats at
5 and 50 ppm but not at 500 ppm. Taken
together, the available studies show a
limited carcinogenic potential from. .
drinking water ing«*tion, Thii may
relate in part to poor absorption of
beryllium from ingestion. It has been
postulated that ingested beryllium is
precipitated in the gastrointestinal tract
as beryllium phosphate, making it
inaccessible for absorption.
In general, the mechanisms of
absorption of metallic ions are not well
understood and do not follow a dose-
response relationship. On the other
hand, there .is clear evidence of
carcinogenicity of beryllium via
inhalation or injection in monkeys, rats
and rabbits. Studies in animal species
exposed to beryllium by inhalation or
injection showed tumors at sites
different from the route of exposure
[IRIS, 1989]. Because beryllim produces
tumors in several species (rats.
monkeys, and rabbits) via inhalation or
injection, the Agency has concluded that
the overall weight of evidence provides
sufficient evidence of carcinogenicity;
therefore beryllium is classified by the
Agency in Group B2 as discussed in the
proposal. However. EPA has also placed
beryllium in drinking water Category II
(rather than Category L as proposed) for
regulation.
In response to public comments, EPA
reevaluated the categorization of
beryllium by reconsidering its potency,
exposure, and pharmacokinetics. EPA
changed its categorization of beryllium
from Category I to Category II based on
several factors. This contaminant is
poorly absorbed from the
gastrointestinal tract and the majority
of the ingested beryllium passes through
the gut unabsorbed with less than one
.percent being absorbed. Also it is noted
that while the carcinogenic potential for
beryllium is viewed as Group B2 based
on the overall weight of evidence of the
inhalation and ingestion data, the dose-
response analysis for ingestion exposure
does not provide adequate evidence of
carcinogenicity from a drinking water
source, as is true with many of the other
B2 contaminant*. Therefore, in- setting
an MCLG for beryllium k> drinking
water. EPA believes that a Category U
approach (which include* a safety factor
for possible carcinogenic potential) Is
.appropriate based on the weight of
evidence- for cardnogenidty via
ingestion. and also bated on the
potency, exposure and.
phannacokinetict of this chemical. EPA
believes that these factors justify
changing the categorization of beryllium
from Category I to Category II.
For Category II contaminants, EPA
generally sets the MCLG based upon
noncarcinogenic endpoints (using the
RfD approach) with a safety factor
ranging from 1. to 10 applied .ta account, .
for possible caremogenicity. As stated in
the July 1990 notice (55 FR 30378). EPA
selected a lifetime oral study in rats
(Schroeder et al., 1970) to derive the RfD
and the DWEL for beryllium. An RfD of
0.005 mg/kg/day was derived from this
study using an uncertainty factor of 100
(per NAS/EPA guidelines for use with a
chronic study). This results in a DWEL
of 0.2 mg/1 and an MCLG of 0.004 mg/1.
The derivation of the beryllium MCLG is
given below.
own. •
MCLC
).S »a/lco/dav * 70 fro
100 x 2 Ut*r*/d*y
0.2
• °-004
The DWEL is based on a 70-kg adult
consuming 2 liters of drinking water per
day. The MCLG includes an additional
safety factor of 10 to account for
possible carcinogenic potential of this
contaminant via ingestion and assumes
a drinking water contribution to total
intake of 20 percent.
The Agency disagrees with the
comment alleging inconsistencies with
other drinking water regulations. To set
regulations (including those for nickeL
cadmium, chromium, antimony, and
asbestos, as well as the MCLG for
beryllium), each contaminant was
evaluated independently to assess the
available health effects data for drinking
water. EPA considered the overall
weight of evidence to determine
carcinogenic potential. The factors
considered included carcinogenic
potential by ingestion in addition to
other factors, e,g^ cancer potency. •
pharmacokinetics, and exposure. The
above inorganic contaminants are all
classified in Group A or B according to
the Agency's classification scheme, but
were placed into different drinking
water categories from those that would
typically apply to the particular
classifications. The commenter is
mistaken that EPA classified these
contaminants as Group C or D
carcinogens by the oral route of
exposure. Asbestos (cancer
classification A) was placed in drinking
water Category D due to limited
evidence of cardnogenidty from
drinking water cadmium (cancer
classification Bl) was assigned to-
-------
31786 Federal Ragkter / y^ 57. NQ. i3& / Friday. July 17. 1992 / Rule* and Regulations
drinking water Category III due to lack
of evidence of carcinogenicity from
drinking water (56 FR 3536). MCLGi for
chromium (as chromium VI) (56 FR 3537)
and nickel (as refinery dust) (55 FR
30382) (proposed), both belonging to
cancer classification A based on the
inhalation route of exposure, were set
following a Category III approach since
data by the oral route show no evidence
of carcinogenicity. In short, a case-by-
case decision on the categorization of a
contaminant with respect to its
carcinogenicity from drinking water
ir.gestion is made based on the strength
and overall weight of evidence.
EPA also received two health effects
studies on beryllium submitted during
the December 1991 NOA comment
period. The comment period for
beryllium closed in October 1990. No
additional comments were solicited on
beryllium during the NOA period. In
addition, both studies do not appear to
be peer-reviewed as published. Results
of a preliminary review of these studies
do not indicate they would lead to a
change in the RfD or MCLG for
beryllium.
One of the studies, by Morgareidge
(1976). reported that in dogs, a maximum
tolerated dose was likely just above 1
mg/kg/day. a level higher than the 0.54
mg/kg/day NOAEL from the Schroeder
et al. (1970) study above. The other
study, by Ward et al. (undated), is an
epidemiology study of beryllium
workers which presents no dos«
response information.
Consequently, after review of the
timely public comments and •
reassessment of the information on
cancer and other toxicity concerns, EPA
Is placing beryllium in Category II for
the reasons stated above, and
promulgating an MCLG of 0.004 mg/L
c. Cyanide. EPA followed a Category
III approach and proposed an MCLG of
0.2 mg CN'/l for cyanide in the July 25,
1990 proposal (55 FR 30379). The Agency
has classified cyanide in Group D since
there are insufficient human and animal
studies for an assessment of iU
carcineogenicity. A DWEL of 0^6 mg
CN~/1 was derived using a NOAEL
value of 10.8 mg CN"/kg/day from a "
two-year dietary study in which rat*
were administered diets containing
hydrogen cyanide (Howard and HanzaL
1955). In calculating the DWEL. in
uncertainty factor of 100 was applied (in
accordance with NAS/EPA guidelines
for a lifetime animal study). An
additional modifying factor of 5 was
used to account for the possibility that
cyanide would be absorbed more
readily from drinking water than from
food. The 0-2 mg CN~/1 propoeed MCLG
is a rounded value (from OJ5 mg CN~/1)
derived from the DWEL and assuming a
relative source contribution of 20% due
to exposure from drinking water.
Public Comments: A total of eight
individuals or organizations provided
comments in response to the MCLG
proposal regarding cyanide. Six
commenters raised, the issue of cyanide-
: speciation. These commenters stated
that while the proposed MCLG is based
on "free cyanides." the proposed
analytical methods imply that "tola!
cyanides" will be regulated. While "free
cyanides" are readily bioavailable and
extremely toxic, "total cyanides"
contain all cyanides, including those
low-toxicity. inert species that are
undissociable (to CN~) and not
absorbable (see the Analytical Methods
Section for additional information).
Two commenters questioned the
appropriateness of the NOAEL (10.8 mg
CN~/kg/day) that was selected for the
MCLG calculation. One commenter
suggested that the study by Howard and
Hanzai (1955) is not preferable since no
effects were observed in rats at the
highest test dose level of 10.8 mg CN"/
kg/day, and studies should be designed
to show an effect at the highest dose
tested. Thus, this commenter claims that
no NOAEL was identified. The other
commenter stated that the rat LD*.
(reported range of 1-4 mg CN"/kg) is
lower than the NOAEL(10.8 mg CN'/kg/
day) used in the MCLG calculation. The
commenter questioned whether the
proposed MCLG will pose an acute
hazard if a large amount of water was
ingested at one time. Also, two
commenters questioned the necessity of
using a modifying factor of 5 in the
. derivation of the MCLG since the actual
bioavailability of cyanide was not
measured upon oral exposure through
diet or drinking water.
EPA Response: In response to the
comments concerning cyanide
speciation. EPA is promulgating today
an MCLG and MCL for cyanide that
apply only to free cyanide. The Agency
agrees with the commenters that only
free cyanides should be regulated
because these are the species of heahh
concern due to their bioavailability and
toxicity. The analytical methods issue is
fully addressed in the Analytical
Methods section of this rule. In
summary. EPA is specifying the use of
the "cyanide amendable to cbJorination"
test for determining the "free cyanide"
concentrations, while the "total
cyanide" analytical technique is being
allowed to screen samples. If the "toUl
cyanide" results are greater than the
MCL. then the analysis for free cyanide
would be required to determine whether
there is an exceedance of the MCL.
EPA considers the NOAEL selected to
be appropriate and to be protective
against adverse health effects over a
lifetime of exposure. The selection of a
NOAEL of 10.8 mg CN'/kg/day is based
on sensitive endpoint of toxicity and is
consistent with a study that found a
. NOAEL of »mg/kgCN-per day for '
weight loss, thyroid effects, and myelin
degeneration in rats reported in a 11.5-
month dietary study using KCN
(Philbrick et al.. 1979]. The commenter
noted that the reported low LDM in rats.
was lower than the selected NOAEL
However, the rat lethal dose of cyanide
was an acute effect obtained by
administering cyanide in bolus form by
gavage. The NOAEL chosen is from a
two-year chronic dietary study. Studies
have shown that rats (and humans) can
tolerate higher doses of cyanide (80 mg
CN~/kg/day) when mixed in the diet
[Kreutler et al.. 1978) than when
adminidtered in bolus form by gavage in
aqueous solution (LD,.=4 mg CN"/kg/
day) (Ferguson. 1962). Rats also
tolerated a higher oral dose of cyanide
(12 mg CN"/kg/day for 21 days that was
administered in drinking water Palmer
and Olson. 1979). The intermittent
ingesrion of low doses over a day would
allow for sufficient detoxification.
Using the NOAEL chosen, an
uncertainty factor of 500 was used in the
calculation of the DWEL. This includes
an uncertainty factor of 100 (for use of a
NOAEL derived from a Chronic Study)
and a 5-fold modifying factor to account
for the fact that the NOAEL is from a
dietary study.
The fatal oral dose of cyanide in
humans reported by several
investigators ranged from 0.5 to 3.5 mg/
kg CN-. The LD*° values and LOAELs
for various acute (1-14 days) and
subacute (90 days] effects in tested
- animals were reported in the same range
as the human lethal levels or higher
(USEPA. 1988b. finalized as USEPA.
1992h]. Assuming an average human
body weight of 70 kg, the approximate
fatal dose of CN" would be no less than
35 mg (04 mg/kgx70 kg). At the final
MCL of 0.2 mg/1 promulgated today, a
person would need to ingest 175 liters of
water (35 mg+O2 mg/1) in one short
time interval to obtain an acutely toxic
dose, an unrealistic volume to consume.
Therefore, EPA believes the derived
MCLG in protective of both acute and
chronic toxic effects of cyanide in
drinking water.
After review of the comments. t*x
Agency believe* that the proposed
MCLG fir supported by the available
health dttc and is promulg«tinf today
as MCLG of OL2 Bg/I for free cyanxi*.
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Federal Register / Vol. 57, No. 138 / Friday, July 17. 1992 /Rules and Regulations
31787
d. Nickel. On July 2S. 1990. EPA
proposed an MCLG of 0.1 mg/1 for nickel
(55 FR 30381]. The MCLG was based on
the Ambrose et al. 1976 study where rats
were fed nickel sulfate hexahydrate in
their diet for 2 years. Effects noted in the
animals included decreased body
weight in male and female rats, as well
as increased: relative heart weight and' •
decreased relative liver weight in female
rats. Other studies reported decreased
body weight gains and organ weight
effects. A NOAEL of 5 mg Ni/kg body
weight was identified in the Ambrose
study. This NOAEL is supported by a
short term gavage study [American
Biogenics. 1986].
' Nickel refinery dust and nickel
subsulfide are classified in Group A:
Human carcinogen based on human
epidemiologic data from occupational
exposure via inhalation. Nickel was not
demonstrated to be carcinogenic by the
oral route of exposure in several animal
studies. The soluble nickel salts that
may be found in drinking water have not
been classified as to their carcinogenic
potential Nickel is considered to be an
essential trace element for some animal
species, although it has not been shown
to be essential for humans. It is found as
a normal constituent in the human diet.
with average intakes of 100 to 500 jiig/
day. EPA proposed an MCLG for nickel
following a Category III approach
considering the lack of evidence of
carcinogenicity by ingestion.
Public Comments: Comments are
requested on the MCLG for nickel and
the carcinogenicity potential for nickel
in drinking water. Fourteen commenU
were received Comments were received
on the derivation of the MCLG which
discussed the choice of study and toxic
endpoint as the basis for the MCLG, use
of uncertainty factors, assumed volume
of water consumed daily, exposure from
' water and carcinogenic potential for
ingested nickel.
One commenter stated that the dose
of 5 rag/kg/day should be considered a
no-observed-effect level [NOEL) instead
of a no-observed-adverse-effect level
(NOAEL) since no effects, adverse or
otherwise, were noted. They also noted
that the next highest dose (50 mg/kg/d)
could arguably be called a NOAEL
instead of a LOAEL since the effect of
decreased body weight could be the
result of decreased food consumption
possibly due to taste aversion.
A few comments were received on the
use of a 3-fold modifying factor in the
RfD calculation. These commenter* *aid
that EPA should not use the additional
factor of 3 to account for deficiencies in
the data base for reproductive effect*
because the factor of 100 is already
conservative and the available
reproductive data demonstrated a
NOAEL comparable to the Ambrose
study. It was suggested that EPA defer
establishing an MCLG for nickel until all
reviews of reproductive studies are
completed, which would eliminate the
need for a modifying factor of 3.
Comments were received which
discussed: consideration of reproductive :
or dermatitis studies related to nickel in
drinking water as the basis for the
MCLG. These studies suggest that
reproductive or derma tological
endpoinrs may be more sensitive than
the Ambrose feeding study! The
commenters agreed with EPA's position
that the reproductive and dermatitis
studies were not appropriate, to serve as
the sole basis for the RfD due to
problems with the study design. The
commenters stated further that EPA has
been more than conservative in using
the NOAEL from the Ambrose feeding
study, that there may be a potential for
differential absorption from food versus
water, and that the reproductive and
dermatological studies in fact support
the current RfD estimated from the
Ambrose feeding study. Another
commenter indicated that ingested
nickel exerts its toxicity through
irritation to the gastrointestinal tract
and not inherent toxicity due to low
intestinal absorption.
One commenter indicated that the
DWEL should not be adjusted by a
relative source contribution from water
in that the DWEL is already
conservative and that actual exposure
data should be used. Because actual
data show less exposure than EPA's
default relative source contribution, the
MCLG should be 5 to 8 times higher than
it is. They further stated that the volume
of 2 liters of water per day was an
overestimate and that a vahie of 1.4
liters/day taken from the
recommendations of the EPA Exposure
Assessment Group should be used.
Several commenters supported EPA's
position not to treat nickel as a
carcinogen in drinking water.
EPA Response: EPA maintains that
the 5 mg/kg/day dose level in the
Ambrose feeding study is appropriately
considered a NOAEL and that the higher
dose of 50 mg/kg/day is a LOAEL In
females given the done of 50 mg/kg/day,
decreased body weight increased
relative heart weight and decreased
relative liver weight were all
statistically significant Therefore, based
on scientific judgment and statistical
significance (concurred in by SAB), SO
mg/kg/day is considered the LOAEL.
All of the above effects were also
observed at the lower dose level of 5
mg/kg/day but were not statistically
significant. Thus, the 5 mg/kg/day level
is a NOAEL
EPA agrees that nickel may be
irritating to the gastrointestinal tract;
however, there is evidence to indicate
systemic effects following chronic low
dose exposure. Therefore. EPA
disagrees that nickel lacks inherent .
toxicity.- . • • • • • • .,-
EPA disagrees that the modifying
factor of 3 is not justified. While the
existing reproductive studies are not
adequate for use as the sole basis for the
RfD and DWEL they do indicate a
potentialreproductive hazard that may
result from oral exposure to nickel. A
modifying factor of 3 accounts for the
uncertainties for the equivocal nature of
the dose-response data from the existing
reproductive studies.
EPA agrees with the comments that
the dermatological studies should not be
the basis for the NOAEL in that oral
nickel challenge studies ideally should
be conducted in a double blind manner.
The commentators and EPA agree.
however, that the dermatological and
reproductive studies support the RfD
and DWEL in a weight-of-e\ idence
approach.
The Agency disagrees with the
commenter who stated that the DWEL
should not be adjusted by a relative
source contribution but that actual
exposure data showing lower exposure
should be used. EPA agrees that
available data indicate that drinking
water contributes less than 20 percent of
.the daily intake, but EPA uses 20
percent as a minimum percentage in
these cases (see "Relative Source
Contribution" section above). •
In response to the commenter's
suggestion to use 1.4 liters/day as the
assumed water consumption instead of 2
liters/day, EPA continues to believe that
the use of 2 liters/day is appropriate in
setting the MCLGs. as recommended by
NAS (1977). The Agency has
consistently used 2 liters/day as an
assumed consumption in past drinking
water regulations. The NAS estimate
was based on a survey of nine different
literature sources which gave an overall
average per capita water (liquid)
consumption per day of 1.63 liters. It
also concluded that the volume of 2
liters/day represented the intake of the
majority of water consumers. In order to
be conservative and allow for an
adequate margin of safety, EPA uses the
2 I/day value. Further, the use of 1.41/
day in the EPA Exposure Assessment
Group handbook is not inconsistent with
EPA's approach of using 2 I/day in this
and other, drinking water rules. The 1.41
value is an overall average of a number
of studies, tome of which did not
-------
317bb Federal Regiiter / Vol. 57. No. 130 / Friday. July 17. 1992 / Rules and Regulations
necessarily consider indirect water
consumption (such as use in cooking).
Therefore, to best account for all
exposures related to the occurrence of
contaminants in drinking water. EPA
believes use of 2 liters daily water
intake is conservative and appropriate.
The Exposure Assessment.Group.-. •••
Handbook also notes that 2 liters intake
is a reasonable worst case estimate.
With respect to a factor to account for
potential differences in absorption of
nickel from food and water, EPA
acknowledges that data are available
which suggest a potential for differential
absorption. However, these differences
are not clearly reflected in the dose-
response relationships from the toxicity
studies. In particular, the gavage study
[American Biogenics. 1986] exposed rats
to nickel chloride dissolved in water.
This study identified the same NOAEL
(5 mg Ni/kg/day) as the dietary study
[Ambrose et al.. 1976] which serves as
the basis for the RfD. Thus, application
of a modifying factor to account for
differential absorption is not considered
to be justified by the existing data.
After review of the public comments,
EPA is promulgating the MCLG for
nickel at 0.1 mg/1. as proposed.
e. Sulfate. In the July 25,1990 notice.
EPA proposed two alternative MCLGs of
400 and 500 mg/1 for sulfate. People who
continually ingest high levels of sulfate
in their drinking water generally
acclimate to the sulfate and are resistant
to its laxative properties. Even though
promulgation of the MCLG is being
deferred, for reasons discussed in
Section IILB.5 of this notice, a
discussion of comments received and
EPA's response follows below.
Public Comments: There were 15
separate comments concerning sulfate.
Several commenters believed that EPA
should npt regulate sulfate due to a lack
of adequate health data, lack of chronic
effects and because of acclimatization
(refractoriness to the laxative effects) to
sulfate. Eleven commenters stated that
the sulfate regulation should be higher
than 500 mg/1 (between 600 and 1.000
mg/l). Six commenters stated that 500
mg/1 was protective, while three others
believed that the 400 mg/1 option would
be better. One commenter stated that
the usual approach for deriving the
MCLG—an RID and DWEL
calculation—should be used for sulfate.
Another commenter cited a 1989 letter
dated July 17,1989 from the Metals
Subcommittee of the Science Advisory
Board's Environmental Health
Committee to the Administrator stating
that the Subcommittee could not support
the setting of an acute DWEL. Other
commenters urged no regulation of
sulfate, stating thct: a secondary MCL is
sufficient for sulfate, infants as well as
adults acclimate to sulfate. sulfate is
present in food, and the WHO
guidelines are based on taste and not on
health effects.
EPA Response: As noted above. EPA
is deferring action on the sulfate MCLG
and MGL. Some-commenters'noted that''
no chronic health effects have been
associated with long-term exposure to
high levels of sulfate. However, sulfate
can have acute adverse effects on non-
acclimated persons. The critical health
effect that results from exposure to
sulfate in drinking water is diarrhea.
Diarrhea has been reported at a level as
low as 630 mg/1. The population most
likely to experience this effect consists
of travelers and infants not accustomed
to high sulfate levels. This laxative
effect eases and disappears (i.e., the
person acclimatizes to the effects of
sulfate) with continued exposure to high
levels of sulfate in water. Little or no
information is available on how quickly
people, particularly infants, acclimate to
the effects of sulfate.
Due to the acute nature of the critical
effect, an RfD and chronic DWEL were
not determined. Available data indicate
that infants may be the most sensitive
subpopulation since they may be at risk
of becoming dehydrated (which may be
serious if not properly treated) as a
result of prolonged diarrhea [Chien et
al.. 1968J.
The Metals Subcommittee of the
Science Advisory Board's
Environmental Health Committee
recommended additional study before
regulation but noted that, if regulated
an MCLG of 400 mg/1 [Loehr, 19891 was
more appropriate than the 200 mg/1
recommended at the time by the
Agency. The basis for the SAB
recommendation was that (1) the mode
of action of sulfate is fairly well known.
and (2) some human data are available
which indicate that ill effects occur only
at concentrations above 600 mg/1.
At the time EPA proposes a decision
on sulfate. it will present a discussion of
its science assessment, including any
new information which may'become
available.
f. Thallium. EPA proposed an MCLG
of 0.0005 mg/1 for thallium in the July
1990 proposal [55 FR 30383J. The MCLG
was derived using a NOAEL of 0.2 mg
thallium/kg/day from a 13-week dietary
study in rats [Stoltz ei-al. 1986]. Based
on this NOAEL. a DWEL of 0.0023 mg/1
was calculated. An uncertainty factor of
1,000 was applied (in accordance with
NAS/EPA guidelines for a subchronic
study). An additional uncertainty factor
of 3 was used to account for the lack of
adequate reproductive data. EPA ha*
classified thallium in Group D since
there is inadequate evidence of
carcinogenicity. No new data that would
change the conclusions presented in the
July 1990 notice have become available
since its publication.
Public Comments: In response to the
.July. .1990 notice..three individuals on^'"-'-'
organizations commented on the
proposed MCLG for thallium. The most
significant area of comment was the
claim that the uncertainty factor of 3.000
used to establish the MCLG for-thallium
is overly conservative given the nature
of the health effects data involved, and
that an uncertainty factor of 1,000
should be sufficient. The commenter did
not believe that an extra uncertainty
factor of 3 was warranted for protection
from potential reproductive effects.
EPA Response: EPA disagrees that the
uncertainty factor of 3.000 is overly
conservative. The only data available
are from subchronic exposure of
rodents. A factor of 1,000 is generally
used with a NOAEL derived from an
animal study of less-than-lifetime
duration (the 1986 Stoltz et al. study was
13 weeks in length). The additional
uncertainty factor of 3 was applied in
the risk assessment to compensate for
the lack of adequate reproductive data.
In light of the results from Formigli et al.
(1986) in which thallium induced
testicular toxicity in rats at 0.74 mg
thallium/kg/day administered in the
drinking water for 8 weeks, EPA
believes it is appropriate to use an
additional uncertainty factor of 3 since
the possibility that this effect may occur
at doses at or below the selected
NOAEL of 0.2 mg thallium/kg/day
cannot be ruled out. Detailed
descriptions of thallium toxicity at
different dose levels and in different
animal species are documented in the
thallium Health Criteria Document
prepared in support of this regulation
[USEPA. 1990g, finalized in USEPA.
1992cJ. Accordingly, based on the
available information, the Agency is
promulgating today an MCLG of 0.0005
mg/1 for thallium.
4. Organic MCLGs
a. BenzofaJPyrene and other PAHs. In
the July 1990 notice, EPA discussed the
available information on the health
effects, occurrence and human exposure
for 15 Polynuclear Aromatic
Hydrocarbons (PAHs) {55 FR 30396]. Of
the 15 PAHi. seven were presented in
greater detail because of their
carcinogenic potential (all classified as
Group B2, probable human carcinogen),
and were proposed for regulatory
consideration. These included:
Benz[a]anthracene (BaA).
benzo[ajpyrene (BaP).
-------
Federal RagUtet / VoL 57. No. 138 / Friday. July 17. 1992 / Rules and Regulation* 31783
benzo[b]fluoranthene (BbF).
benzo[kjfluoranthene (BkF). chrysene
(CHY). dibenz[a.h]anthracene (DBA).
and indeno(1.2.3-c.d]pvrene (IPy). In tne
proposal. EPA presented alternative
approaches for controlling exposures: (1)
Setting MCLG of zero for BaP alone.
based on its carcinogenic potential and
(2) setting an MCLG of zero for each of
the seven carcinogenic PAHs. Only for
. BaP are sufficient data available to
make a quantitative estimate of cancer
potency. In a study wherein mice were
fed BaP in the diet treatment-related
gastric tumors developed, another
dietary study in rats produced similar
results. Data from these studies form the
basis for the quantitative estimate of
cancer potency [Neal and Rigdon. 1967).
BaP is mutagenic in vitro mutagenicity
tests, and has been found to produce
reproductive effects in animals. Skin
painting studies in animals indicate that
the effectiveness of inducing skin cancer
of the other six PAHs are equal to or
less than that of BaP (see studies cited
in Criteria Document [USEPA. 1988C.
finalized as USEPA, 1991f])- The Federal
Register notice solicited public
comments on: The Agency's two
alternative options: regulation of other
PAHs: and alternative approaches for
evaluating the carcinogenic potency for
BaP. The major comments are discussed
below.
Public Comments: There were 17
comments submitted to the Agency
concerning health-based issues on the .
proposal to regulate PAHs. Eight of the
comments stated that the Agency should
limit the regulation to BaP only. Three of
the comments suggested regulating all
seven of the Group B2 PAHs using a
comparative potency approach, with
comparison to BaP. One comment
indicated that individual MCLGs should
be established after the comparative
potencies are validated. The validation
method was not specified. There were
several comments which suggested that
the Agency should not regulate PAHs.'
The basis claimed for this
recommendation was either that data to
determine health effects were not
sufficient, or that exposure to PAHs in
drinking water was negligible when
compared to other sources. There also
were comments that did not agree with
the Agency's approach of selecting
Category I and setting a zero MCLG for
contaminants'that show evidence of
carcinogenicity via ingestion. Some
commenters described the Agency's
approach as being overly conwrvative:
overestimating riskiand not accounting
for a threshold of carcinogenicity.
Specific suggestions were: (1) To set
MCLGs/MCLs at a de minimus level
(e.g.. 10~4) or at background levels: (2)
use a biologically based (e.g., two-stage
or fitted multistage} model to estimate
cancer risk, instead of the linearized
multistage model: and (3) use body
weight scaling, instead of surface area.
to extrapolate animal data to human
exposure* for estimating cancer risk:v .-
EPA Response: EPA has decided to
establish an MCLG (and MCL) for BaP
only. There are-extensive and sufficient
data to support regulating BaP. It has
been shown to be carcinogenic in
animals by many routes, including by
ingestion. and has been classified by the
Agency as a Group EZ probable human
carcinogen. Even though less than one
percent of PAH exposure may come
from drinking water, PAHs have been
found in some drinking water sources.
The Group B2 classifications and
frequency of association of the other six
PAHs with BaP as a mixture in drinking
water suggest that it may be appropriate
to regulate these others also. The
Agency is considering regulating BaA.
BbF, BkF, CHY. DBA, and IPy using a
comparative cancer potency approach;
the individual potencies would be
compared to that of BaP. Such regulation
may be proposed at a future date when
EPA has established a policy for how
such a comparative approach would be
conducted, or when other appropriate
data become available for any or all of
the six PAHs.
The EPA approach to estimating
cancer risk for drinking water
contaminants (i.e., weight-of-evidence
determination and non-threshold low-
dose extrapolation) is considered to be
the most prudent approach that is
protective of human health. The Agency
considers and evaluates alternative
methods for assessing human health
risks to chemicals. Risk estimates using
a variety of models (including two-stage,
linearized multistage, and Weibull
methods) have been applied to the BaP
data. In the interest of using more of the
available data, the slope factor of 5.76
(mg/kg/dayr1 was derived. This slope
factor is the geometric mean of all the
models used. While data on the
potential mechanism of action of an
agent are considered in the weight-of-
evidence judgment, evidence of a
nongenotoxic mechanism, while
pertinent, would, not always exclude
classification of'a chemical as a
probable human carcinogen. The
appropriate scaling factors for
interspecies extrapolation are being
reviewed currently by the EPA and
other Federal agencies. However, the
Agency will continue to use surface area
scaling to estimate cancer riiks until
there is sufficient evidence to support a
change and until another approach is
fully approved and adopted.
Based on the above discussion, which
considers the toxicity. carcinogenicity.
occurrence, and exposure of BaP. BaA.
BbF. BkF. CHY. DBA. and IPy. EPA has
concluded that only BaP should be
regulated at this time: In most cases, the' "•
Agency places Group B2 contaminants
into EPA Category I when there is strong
evidence of carcinogenicity via
ingestion. EPA's policy is to set MCLGs
for Category I chemicals at zero. Based
on the weight-of-evidence for
carcinogenicity, the Agency places BaP
in Category I and is promulgating today
an MCLG of zero for this contaminant.
b. Dalapon. In the July, 1990 proposal
[55 FR 30385], EPA proposed an MCLG
of 0.2 mg/1 for dalapon based on a two-
year feeding study in rats [Paynter et aj..
I960]. A NOAEL of 8 mg/kg/day was
identified from this study. From the
NOAEL a DWEL of 0.93 mg/1 was
derived. An uncertainty factor of 100
was applied to the NOAEL following
NAS/EPA guidelines for a lifetime .
study. An additional uncertainty factor
of 3 was used to account for possible
inadequacy of the available animal
data.
Public Comments: Three comments
were received on the health effects of
dalapon that were editorial in nature.
There was no major disagreement
between any of the commenters and
EPA. One commenteT misread the .
uncertainty factor of 300 as 800. The
second commenter agreed on the value
but suggested the use of the term
"uncertainty factor" be used
consistently to account for inadequacy
of toxicological data instead of the term
"modifying factor." The third commenter
needed clarification on the title of a
reference.
EPA Response: EPA agrees with the
commenter that suggested that "3" is an
uncertainty factor (which is synonymous
with "modifying factor") to account for
the inadequacy of the data base.
Because none of the comments affect the
proposed MCLG, based on the available
information, the Agency is promulgating
today an MCLG of 0.2 mg/1 for dalapon.
c. Dichloromethane (Methylene
chloride). In the July 1990 notice [55 FR
30386], EPA proposed an MCLG of zero
for dichloromethane. This MCLG was
based on the classification of this
contaminant as a Group B2 carcinogen.
EPA requested comments on whether
the available carcinogenicity data by
ingestion are adequate to classify
dichloromethane in Group B2. and on
the proposed MCLG.
Public Comments: Eleven comments
were received in responw to the
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3^790 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
proposed regulation of dichloromethane.
The majority of the commentert
questioned the classification of
dichloromethane in Group B2—probable
human carcinogen. One commenter
suggested that EPA should not regulate
dichloromethane as a known human
carcinogen since no human'data are
available. Several commenters argued
for the classification in Group C while
others favored a classification in Group
D. These commenters stated that there
are limited or inadequate data to
classify dichloromethane as a Group B2
carcinogen. One commenter agreed with
the EPA cancer classification in Group
B2 for dichloromethane.
EPA Response: EPA disagrees with
the comment that the Agency is
regulating dichloromethane (DCM) as a
known human carcinogen (i.e.. Group A
carcinogen). The Agency has classified
dichloromethane in the cancer
classification of Group B2. probable
human carcinogen. EPA has placed
dichloromethane in Category I to set the
MCLG* because there is sufficient
evidence of carcinogenicity in animals
from drinking water exposure.
EPA disagrees with the commenters
supporting classification of
dichloromethane in Group C [possible
human carcinogen) or Group D
(inadequate evidence for classification).
EPA believes that there is sufficient
evidence that dichloromethane induces
tumors in animals. In drinking water
studies [Serota et al., 198&a.b], a
statistically significant increase in the
incidence of combined hepatocellular
carcinoma and neoplastic nodules when
compared with matched controls was
observed (female rats). Male mice had
an increased incidence of combined
neoplastic modules and hepatocellular
carcinoma. In an inhalation experiment
[IRIS. 1991a], statistically increased
incidences of mammary adenomas and
flbroadenomas were observed in male
and female rats. Mice also showed
increased incidence of hepatocellular
adenomas and carcinomas. These data
support the classification-of
dichloromethane in Group B2 and
provide specific evidence for ingestion
exposure hazard.
Consequently, based on the
information available to the Agency and
the public comments received. EPA has
concluded that dichloromethane should
be placed in Category L and that an.
MCLG'bf zero. a« proposed. i» '
appropriate.
d. Di(Z-ethylhexyl) adipate. In the July
1990 proposal [55 FR 30384], EPA
proposed an MCLG of 0.5 mg/1 for di(2-
ethylhexyl) adipate (DEHA). This MCLG
was derived from an NTP 2-year dietary
study in rats and mice which resulted in
a NOAEL of 700 mg/kg/day (NTP.
1982a]. An uncertainty factor of 100, and
an extra uncertainty factor of 10 for lack
of adequate reproductive effects data,
were applied to the NOAEL to derive a
DWEL of 25 mg/l. The MCLG of 0.5 mg/1
was calculated for DEHA from this
DWEL by applying an additional safety
factor of 10 in accordance with OW
policy for Group C carcinogens, and by
assuming a 20 percent contribution from
drinking water to total exposure.
Based on new health information (see
discussion below), EPA has recalculated
the proposed MCLG for DEHA. A full
discussion on the basis for the revised
MCLG for DEHA was given in the
November 19.1991 Notice of
Availability (56 FR 60953J.
Public Comments: Two commenters
responded to the July 1990 proposal.
Both commenters questioned the use of
an extra uncertainty factor of 10 in the
calculation of the DWEL to account for
the lack of data on reproductive effects.
One commenter claimed that the extra
uncertainty factor of 10 should not be
used because there are the 1988 ICI
teratology and reproductive studies
available for this chemical [ICI. 1988a.bJ.
One commenter on the NOA asserted
that the 3-fold additional uncertainty
factor should not be justified in part by
the observation of dilated ureters in
fetuses in the ICI study [Id, 1988aJ.
because the noted effect wa* not
statistically significant. If these data
were used to justify use of an
uncertainty factor, a value less than 3
should be used, according to the
commenter.
EPA Response: As discussed in the
November 29.1991 Notice of
Availability. EPA has reviewed the 1988
ICI teratology and reproductive studies
and considers.them.adequate.,and'.,
suiufalt to serve as the basis for the
MCLG for DEHA.
In the teratogenicity study, Wistar-
derived pregnant rats (24/group) were
fed diets containing DEHA to a 300,
1,800 or 12.000 ppm corresponding to
dosages of 0. 28,170 or 1,080 mg/kg/day
on gestational days 1-22 [ICL 1988aJ. At
the high dose, slight reductions in
maternal body weight gain and food
consumption were observed, and
reduced ossification and kinked or
dilated ureters were found in the
fetuses. Slightly dilated ureters were
also seen in a few fetuses at 170 mg/kg/
day but the incidence did not reach
statistical significance. The LOAEL and
the NOAEL for this study were 1.080
mg/kg/day, and 170 mg/kg/day.
respectively.
In a companion one-generation
reproductive study [ICI, 1988bj, group's
of Wistar-derived rats (15 males/dose;
30 females/dose) were administered
DEHA in their diets at the same levels
(0. 28,170 or 1,080 mg/kg/day). After 10
weeks on the diet the animals were
mated to produce one generation of
offspring that was reared to day 38 post
partum. Test diets were fed
continuously throughout the study
(approximately 18-19 weeks of
exposure). No effects were seen on male
or female fertility. However, at the
highest dosage level, there was a
reduction in the body weight gain of the
dams during gestation; an increase in
liver weight in both male and female
parents; and reductions in offspring
weight gain, total litter weight and litter
size. The NOAEL for this study was also
170 mg/hg/day.
Based on the NOAEL of 170 mg/kg/
day, an RfD of 0.6 mg/kg/day and a
DWEL of 20 mg/1 is calculated for a 70-
kg adult consuming 2 liters of water per
day using an overall uncertainty factor
of 300.
DWEL -
3 X 100
0.6 rag/kcr/dav x 70 kg
- 0.56
(rounded to 0.6 mg/Jcg/day)
2 I/day
« 21 mg/1
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Federal Ragirtar / VoL 57. No. 138 / Friday, July 17. 1992 / Rules and Regulations
31791
where:
70 kg is the aisumed body weight of an
adult person
TOO is the uncertainty factor following EPA
guidelines for a NOAEL obtained in a
study using laboratory animals
3 is the additional uncertainty factor used
because of data base deficiencies
including.lack of a multi-generation i:" • .-
reproductive study.
In the November 29.1991 Federal
Register Notice. EPA presented this
recalculated DWEL and the proposed
MCLG for DEHA based on the DWEL of
21 mg/1. an additional safety factor of
10 in accordance with EPA policy for
Category II contaminants and an
assumed drinking water contribution of
20% to total exposure.
MCLS
21 BQ/1
10
X 0.2 - 0.4 stg/1
EPA agrees that because the effect on fetal
ureters in the ICI study [1CI. 1988a] was not
statistically significant, this effect should not
be used in justifying the additional 3-fold
uncertainty factor. However. EPA believes
the data gap cited (lack of a multi-generation
study) does warrant use of the additional 3-
fold uncertainty factor.
Therefore, based on the new toxicity
data. EPA is placing DEHA in Category
II (Group C) and promulgating an MCLG
of 0.4 mg/1 in today'i notice. This MCLG
of 0.4 mg/1 corresponds to a theoretical
cancer risk level of 1.3 x 10*.
e. Di(2-ethylhexyl)phthalate. In the
July 1990 notice [55 FR 30398]. EPA
discussed the available information on
the health effects, occurrence and
human exposure for four phthalates:
di(2-ethylhexyl)phthalate (DEHP). butyl
benzyl phthalate (BBP), dibutyl
phthalate (DBP) and diethylphthalate
(DEP). In that notice. EPA proposed to
set an MCLG of zero for DEHP based on
its classification as a Group B2
carcinogen. The Agency based on the
cancer classification on a weight-of-
evidence approach for sufficient
evidence of carcinogenicity in animals.
DEHP caused hepatocellular adenomas
and carcinomas in both sexes of rats
and mice fed DEHP in the diet The
Agency discussed three regulatory
options which included: regulating only.
DEHP based on its carcinogenicity;
./regulating DEHP and BBP. the latter
based on a systemic toxic endpoint; and
regulating all four phthalates separately,
* based on systemic endpoints for all
. except DEHP. Based on toxicity,
occurrence, and exposure
consideration*, the Agency proposed
that only DEHP should be regulated. The
available occurrence data indicate that
DEHP has been found most often in
drinking water while the three other
phthalates have rarely been found, and
the reported levels of the others are
below levels of health concern. Also.
drinking water is a minor route of
exposure to phthalates in general.
further adding to the likelihood of low
risk. The Federal Register notice,...
solicited public comments on the
Agency's proposal to regulate only
DEHP and also on the other options. The
major comments' are discussed below.
Public Comments: There were five
comments submitted to the Agency
concerning health-based issues on the
proposal to regulate DEHP and other
options. There were no comments
addressing the third option, i.e..
regulating all four phthalates separately.
One commenter agreed with the EPA
proposal to regulate DEHP only.
Another commenter suggested that the
MCLG for DEHP should be based on the
DWEL rather than on its carcinogenicity
because the evidence for carcinogenicity
is insufficient. In support of this
position, the commenter stated that (1)
DEHP's classification as a Group B2
carcinogen has been considered but
never finalized by the Agency; (2) based
on scientific uncertainty (e.g.. with
mechanism of action, structure activity
relationships, potency, genotoxicity,
species differences, etc.) a B2
classification is inappropriate: and. (3)
the European community has concluded '
that DEHP is not a human carcinogen.
The other three comments were about
BBP. The comments on BBP were: (1)
That the MCL should be set only for
DEHP until sufficient data exists to set
MCLs for BBP and other phthalates; (2)
that the classification of BBP in Group C
(possible human carcinogen) is not
sufficient to warrant its regulation: and
(3) that the NOAEL to calculate the
DWEL and MCL is quantitatively
incorrect and should be increased by a
factor of 3 because no dose/response
relationship was found.
EPA Response: EPA does not agree
with the position that there is a lack of
evidence for classifying DEHP as a
probable human carcinogen. According
to the Agency's Guidelines for
Carcinogen Risk Assessment [USEPA,
1986], the overall weight-of-evidence
provides sufficient evidence in animals
to classify DEHP as & Group B2
(probable human) carcinogen. EPA's
CRAVE verified the Group B2
classification for DEHP on November 7.
1987. The classification wa* based upon
the NTP study [NTP. 1982b). which
resulted in a statistically significant
increased incidence of hepatocellular
carcinomas and adenomas in female
raU and both sexes of mic*.
Additionally, there was a statistically
significant increase in the combined
incidence of neoplastic nodules and
hepatocellular carcinomas in high dose
male rats. The 13 factors presented in
the comment, to support the view that
DEHP does not have an appreciable
cancer risk, do not conclusively support
an absence.of cancerrisk to humans-' •. *
(see comment response document for
detailed discussion). The EPA approach.
i.e.. weight-of-evidence consideration
and non-threshold low-dose
extrapolation, is considered protective
of human health and EPA has concluded
that the weight of evidence for DEHP
warrants classification in Group B2.
according to the EPA Guidelines for
Carcinogen Risk Assessment. In most
cases, the Agency places Group B2
contaminants into EPA Category I and
sets MCLGa at zero when there is strong
evidence of carcinogenicity from
drinking water. EPA's policy is to set
MCLGs for Category I chemicals at zero.
The fact that the European communities
have concluded that DEHP is not a
human carcinogen is noted, but it does
not necessitate that EPA adopt such a
position, especially in the context of
setting drinking water regulations
according to the strict standard in the
SDWA ("no known or anticipated"
human health effects with an "adequate
margin of safety"). After reviewing the
public comments. EPA has concluded
that an MCLG of zero, as proposed.
based on the available evidence of
carcinogenicity in animals, is
appropriate for DEHP.
With regard to the comments on BBP.
EPA believes that to set an MCL for BBP
alone would incorrectly suggest (as
discussed above) that the available data
are not adequate to regulate DEHP as a
carcinogen. A DWEL for BBP was
determined based upon systemic toxic
effects to the liver, kidney, and testes.
When selecting a NOAEL. EPA does not
necessarily rely upon the conclusions
published with the study. The NOAEL
for BBP was based upon liver weight
change and the value selected was
corroborated by evidence from other
studies. The rationale for selecting the
NOAEL-can be reviewed in the health
criteria document for phthalates
[USEPA. 1991g]. An additional
uncertainty factor for limited cancer
evidence was incorporated to develop
the proposed MCLG for BBP; however.
the Agency is not finalizing the MCLG at
this time.
Considering the toxicity. occurrence.
and exposure of DEHP and BBP. EPA
has decided to regulate DEHP only
because it appears more likely to occur
in drinking weter and is more toxic.
Based on the weight-of-evidence on
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31792 Federal gagktar / Vol. 57. No. 138 / Friday. July 17. 1992 / Rulea and Regulations
carcinogenicity. the Agency it
promulgating today an MCLG of zero for
DEHP. as proposed.
f. Dinoseb. In the July 1990,proposal
(55 FR 30387], EPA proposed an MCLG
cf 0.007 mg/1 for dinoseb based on a
two-year study in rats [Hazleton. 1977).
A LOAEL of 1 mg/kg/day was identified
from1 this study. An uncertainty factor of
1.000 {as per NAS/EPA guidelines for a
LOAEL) was used in the derivation of
the DWEL of 0.035 mg/1. This LOAEL of
1 mg/kg/day was also supported by a
100-week mouse study [Brown. 1981]
and a 3-generation reproductive study in
rats (Irvine. 1981]. The proposed MCLG
was based upon this DWEL and an
assumed drinking water contribution of
20 percent of the total intake. Dinoseb
was placed in Category III (Group D)
based on the lack of evidence of
carcinogenicity.
Publir Cjmmenls: One comment was
received on the health effects of
dinoseb. The commenter agreed with
EPA that dinoseb should be placed in
Group D (inadequate evidence of
carcinogenicity). However, this
commenter questioned the rationale for
using 1.000 instead of 100 as the
uncertainty factor in the calculation of
the DWEL
EPA Response: The Agency used an
uncertainty factor of 1.000 in the
calculation of the DWEL in accordance
with the NAS/EPA guidelines for use of
a LOAEL in the absence of a NOAEL
from an animal study. Therefore, based
on the available toxicological data for
dinoseb. EPA is promulgating today an
MCLG of 0.007 mg/1 for dinoseb. as
proposed.
g. Dignat EPA proposed an MCLG of
0.02 mg/1 for diquat in the July 1990
proposal [55 FR 30389] following a
Category 111 approach. The MCLG of
0.02 mg/1 was derived from a chronic
feeding study in rats (Colley et al., 1985]
A NOAEL of 0.22 mg/kg/day was
identified from this study. A DWEL of
0,08 mg/1 was calculated by applying an
uncertainty factor of 100. The MCLG of
0 02 mg/1 assumes a drinking water
contribution of 20 percent of the total
intake. EPA has placed this contaminant
in Category HI based on the lack of
information on its carcinogeniciry. No
new data that would change the
conclusions presented in this notice
have become available since its
publication.
Public Comments: EPA received one
comment on the proposed MCLG for
diquat The commenter indicated that an
online computer search of the
Hazardous Substances Data Base
(HSDB) showed that diquat causes
nausea, vomiting, diarrhea, possible
liver and kidney damage, dyspnea, and
pulmonary edema. The commenter also
noted that diquat appears to affect
epithelial tissues primarily and may
attack those of the kidney or lens of the
eye preferentially.
EPA Response: EPA agrees with the
commenter that diquat causes the above
mentioned effects when used at high, •
doses in animal tests. These effects
were discussed in the Health Criteria
Document for diquat prepared in support
of the July 1990 proposal [USEPA. 1990e:
finalized as USEPA. 1992g|. However.
the effects reported in the Federal
Register notice are effects associated
with the critical endpoint of toxicity
used to establish the no-observed-
adverse-effect level (NOAEL) for diquat.
The effects described by the commenter
are acute effects noted only at much
higher dose levels than the dose causing
the critical effects described in the
.notice. Therefore, based on the
available health information, the
Agency is promulgating today an MCLG
of 0.02 mg/1 for diquat as proposed.
h. Endothall: EPA proposed an MCLG
of 0.1 mg/1 for endothall in the July 1990
proposal [55 FR 30390]. The MCLG was
derived from a 24-month feeding study
in beagle dogs [Keller. 1965). This study
identifies a NOAEL of 2 mg/kg/day. A
DWEL of 0.7 mg/l was derived for the
70-kg adult by applying an uncertainty
factor of-100 (in accordance with NAS/
EPA guidelines). The MCLG for
endothall was then calculated at 0.1 mg/
1 by applying a 20 percent contribution
from drinking water. EPA has placed
this contaminant in Category in (Group
D) based on the lack of adequate data
on its carcinogenic potential. No new
data that change the conclusions
presented in this notice have become
available since its publication.
Public Comments: EPA received one
comment on the proposed MCLG for
endothall. This commenter indicated
that there is a one-year dog study
'[Greenough et al.. 1987] with a higher
NOAEL of 6 mg/kg/day that the
commenter believes would be more
suitable for the calculation of the
reference dose than the 2 mg/kg/day
NOAEL from the two-year dog study by
Keller (1965) used by the Agency. He
further indicated that the effects noted
by the Agency in the Keller study
(increased organ weight and organ-to-
body weight ratios) are not in hit
opinion, "clearcut adverse effects"
because no effects on body weight gain
or food consumption were seen at any
dose level.
EPA Response: The Agency agree*
with this commenter that the additional
one-year dog study on endothall
[Greenough et ah, 1987; MRID 4M074S2-
02]. which waa not available at the time
the MCLG was proposed, should be
considered. The data from this study are
summarized below.
In a 12-month dietary study in dogs,
disodium endothall was fed to groups of
four male and four female beagle dogs at
levels of 0.150. 450, or 1.350 ppm
[Greenough-et al.v!967f.-After 6 weeks
of dosing, the dietary level at the highest
dose was reduced to 1.000 ppm because
of anorexia, decreased food
consumption and body weight loss.
Compound intake in the low-, mid- and
high-dose groups was approximately 6.
18 and 35.8 mg/kg/day endothall
disodium. After the highest dose had
been reduced to 1.000 ppm. a partial
recovery of the weight loss was
observed, but the overall weight gain
remained lower than in controls. No
effects on weight gain were observed at
150 or 450 ppm. However, based on the
histologic changes in the liver and
reactive hyperplastic response in the
gastric mucosa. the LOAEL is 450 ppm
(14.4 mg/kg/day endothall ion), and
considering the marginal effects on the
stomach at the lowest level, the NOAEL
is probably slightly lower than 6 mg/kg/
day endothall disodium (equivalent to
4.8 mg/kg/day endothall ion).
The Agency notes that the lowest
dose tested in the Greenough et al. dog
study of 4.8 mg/kg/day endothall ion
(150 ppm) provides supportive evidence
that the noted low grade epithelial
irritation may contribute to more
remarkable effects when the animals are
exposed to endothall for a longer period
of time ao noted in the two-year dog
feeding study by Keller (1965). Although
no effects were observed on body
weight gains or on food consumption in
the two-year dog feeding study
[Greenough et al., 1987], the increased
weights and organ-to-body weight ratios
for the stomach and intestine in this
study were dose-dependent and must be
considered in the risk assessment of this
chemical, considering that It is an
irritant.
The dog appears to b« more sensitive
to adverse effects from endothall than
the other animal species tested (as
discussed in the proposal). EPA has
concluded that the Keller (1965) study is
the most appropriate study based on the
effects noted above. Accordingly? the
Agency in promulgating today an MCLG
of 0.1 mg/1 for endothall. as proposed.
i. Glyphoaate. EPA proposed an
MCLG of 0.7 mg/1 for glyphosate in the
July 1990 proposal (55 FR 30392]. The
MCLG of 0.7 mg/1 was derived from a
three-generation rat study (Biodynamics,
1961a]. This study showed a statistically
significant Increase in kidney lesions.
The NOAEL was identified at 10 mg/kg/
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Ftxferal Register / VoL S7. No. 138 / Friday. July 17. 1992 / Rules and Regulations
day. A DWEL of 3.5 mg/1 was derived
by applying an uncertainty factor of 100.
which is in accordance with NAS/EPA
guidelines. The MCLG of 0'.7 mg/1 for
glyphosate was calculated by applying a
20 percent contribution from drinking
water.
Several additional, toxicity. studies on., .
glyphosate submitted tc the Agency
since publication of the July 1990 notice
have been evaluated. However, these
studies do not provide new information
that would change the MCLG proposed
in that notice. The proposal noted that
EPA has classified glyphosate as a
Category III (Group D) chemical. In
" Joday'a notice, the Agency still places
" "glyphosate in Category III (Group D) for
establishing the MCLG.
Public Comments: In response to the
July 1990 notice, two individuals or
organizations commented on the MCLG
proposal for glyphosate. One commenter
noted that over-exposure to glyphosate
may result in mucous membrane
irritation, abdominal pain, vomiting,
hypertension, oliguria. and anuria. The
other commenter claimed that the July
1990 notice did not document
adequately the results of some of the
toxicological studies with glyphosate
and did not include the most recent data
on this chemical, such as a new two-
generation rat reproduction study
[Reyna. 1990), which concerned much
higher doses than the 1981 three-
generation rat study by Biodynamics
that was used in establishing the
proposed MCLG. This commenter also
claimed that the oral LD* in mice is 10
g/kg and that information on the
toxicokinetics of glyphosate is not "very
limited" as stated in the July 1990 notice.
The commenter requested that the
discussion of the chronic rat study of
1981b by Biodynamics be revised as
follows:
Because of the absence of a dose-
dependent effect, the lack of preneoplastic
changes, the wide variability in the
spontaneous incidence of thil tumor, the
similarity in incidence between the high dote
group and historical controls, the lack of any
evidence of genotoxicity. it was concluded
that the observed incidence did not
demonstrate an oncogenic response
(emphasis added).
and that the statement on the three
generation rat study of 1981a by
Biodynamics also be corrected to:
In the three-generation rat reproduction
study and addendum, the mott significant
'"•' finding was focal, unilateral, renal tubular
dilation in the kidneys of male pup* for the
ft* generation of high-dote d«m* (30 mg/kg/
day). The NOEL for thii effect wit 10 mgykg/
day. No effects on fertility or nproducUv*
parameters were noted" (emphasis added).
EPA Response: In response to the first
commenter, the Agency notes that acute
effects are already discussed in the
Health Criteria Document for glyphosate
[USEPA. 19SOfl. The preamble to the
proposal generally discussed only
effects noted at the lowest effect level
and not the acute, toxicity effects that ...
may occur at much higher dose levels.
In response to the second commenter,
the Agency agrees to include the revised
language quoted above in the Public
Comment Response Document [USEPA.
1992aj with respect to both the three-
generation rat reproduction study
[Biodynamics, 1981a] and the chronic rat.
study [Biodynamics. 1'98'lb], The Agency
believes that this-revised language is
appropriate. It does not change the
bases for the MCLG. The criteria
document [USEPA. lSS2bJ discusses
these issues in detail.
On reconsideration, the Agency'
agrees with this commenter that the
data on the toxicokinetics of glyphosate
is not "very limited". The available
information as documented in the
updated Health Criteria Document for
glyphosate (1991) indicate the 97.5
percent of the absorbed dose by rats is
eliminated in urine and feces. The alpha
half-lives ranged from 2.11 to 7.52 hours
for males and 5 to 6.44 hours in females
while the beta half-lives ranged from 69
to 181 hours and 80 to 337 hours for
males and femates, respectively.
In response to the commenter's
statement that the LEWi in mice is 10 g/
kg, a lower LDw in mice of 1.6 g/kg was
reported by Bababunmi et al. (1978), as
noted in the proposal.
The Agency also notes that a new
lifetime rat feeding study [Stout and
Ruecker, 1990, MRID #416438-01.
volumes 1-6] was recently submitted to
the Agency and is being reviewed. As
per the commenter's recommendation to
use the new two-generation rat study
[Reyna, M.S.. 1990, MRID #416215-01).
for the MCLG calculations, this study
was submitted to the Agency only
recently and is fully described in the
updated Health Criteria Document
[USEPA. 1992b| prepared in support of
today's rule. This new study is still
under evaluation by the Agency. It i»
unlikely that this study wiO be
considered an appropriate basis for the
NOAEL and MCLG because the NOAEL
in this study is 500 mg/kg/day, whereas
adverse effects were noted at a much
lower dose level (30 mg/kg/day) in the
"three-generation reproduction study In
rats [Biodynamics, 1881a).
Therefore. EPA has concluded that the
three-generation study in rat*
[Biodynamics, 1981a| is appropriate for
the derivation of the MCLG for
glyphosate. and is promulgating today
an MCLG of-0.7 mg/1 for this
contaminant, as proposed.
j. Hexachlorocyclopentadiene (HEX).
EPA proposed an MCLG of 0.05 mg/1 for
hexachlorocyclopentadiene in the July
1990 proposal [55 FR 30394). The MCLG
of 0.05 mg/1 was derived from a 13-week
oral toxicity study .in rats. (SRL 1981).. •••-•
The only effect reported was slight
depression of body weight. A NOAEL of
10 mg/kg/day was identified from this
study. A DWEL of 0.25 mg/1 was
calculated by applying an uncertainty
factor of 1.000. which is appropriate for
use with a NOAEL derived from animal
study data that are significantly less-
than-lifetime in duration. The MCLG of
0.05 mg/lwas calculated from the
DWEL of 0.025 mg/1 by applying 20
percent contribution from drinking
water. No new data that would change
the conclusions presented in this notice
have become available since its
publication.
Public Comments: EPA received one
comment on the proposed MCLG for
hexachlorocyclopentadiene in the July
1990 notice. The commenter indicated
that the toxicity data in the SRI study
are inadequate to justify setting an
MCLG and suggested that EPA postpone
regulation of hexachlorocyclopentadiene
until adequate toxicity studies are
available.
EPA Response: Although EPA realizes
that the toxicity data base is not as
extensive as-for some contaminant*.
EPA believes that there are sufficient
toxicity data to regulate
hexachlorocyclopentadiene. The SRI
data were reviewed by the Agency's
Reference Dose (RID) Workgroup, which
verified the Reference Dose using these
data. In addition. EPA is required by the
1988 amendments to the SDWA to
regulate hexachlorocyclopentadiene.
Therefore, based on the available data.
the Agency U promulgating today an
MCLG of 0.05 mg/1 for
hexachlorocyclopentadiene, as
proposed.
k. Simazine. EPA proposed an MCLG
of 0.001 mg/1 for simazine in the July
1990 proposal [55 FR 30402). The MCLG
was derived from a DWEL of 0.058 mg/1
(rounded to 0.06 mg/1), applying a 20
percent contribution from drinking
water and an additional 10-fold safety
factor by considering the classification
of simazine in Category II (limited
evidence of carcinogenicity from
drinking water). The MCLG was based
upon a NOAEL of 0.5 mg/kg/day for
non-carcinogenic effects in a 2-year rat
chronic feeding/oncogenic study
[McCormick et aL, 1988, MRID #406144-
05) and was supported by a NOAEL of
0.7 mg/kg/day in a 1-year dog feeding
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31794 Federal Register / Vol. 57. No. 138 / Friday, July 17. 1992 / Rules and Regulations
study [McCormick and Green. 1988,
MRID =406144-021-
Several uncertainty factors were
applied to this NOAEL: 10-fold to
account for mterspecies extrapolation
and another 10-fold to account for
intraspecies variability, plus an
additional 3-fold factor to account for
the absence of an adequate study (data'-
gap) to assess the potential toxic effects
of simazine on reproduction. The
proposal also indicated that if '.he data
gap for reproduction is filled before
finalizing the simazine MCLG and if the
data from this study would not raise any
specific lexicological concerns at the
dose used in the calculation of the
MCLG. 0.5 mg/kg/day. the 3-fold
uncertainty factor may be dropped and
the DWEL would then be 0.2 mg/1 and
the MCLG would be 0.004 mg/1 [55 FR
30404. footnote]. This MCLG lies in the
range of 10"l cancer risk estimates.
As noted in the November 29.1991
Notice of Availability, subsequent to the
July 1990 proposal, the data gap •
concerning reproduction effects has
been filled. The Agency recently
received a two-generation rat
reproduction study [Eps'tein. 1991. MRID
=418036-01] where simazine was tested
at 10,100 and 500 ppm (these doses are
equivalent to 0.5. 5 and 25 mg/kg/day
using Lehman (1959} conversion from
ppm to mg/kg/day) assuming rats
consume 5 percent of their body weight
daily. No effects were noted in this
reproduction study at the dose level (0.5
mg/kg/day) used to calculate the MCLG.
In light of these data. EPA indicated in
the Notice of Availability of November
29.1991 that it was considering dropping
the 3-fold uncertainty factor from the
calculation of the DWEL and the MCLG
for simazine as EPA had indicated it
would do in the proposal [55 FR 30404.
Footnote]. EPA has now decided in
today's final rule to drop the 3-fold
uncertainty factor. Accordingly, the
proposed DWEL end MCLG of 0.06 and
0.001 mg/U respectively, are modified
and finalized (after rounding) at 0.2 and
0.004 mg/1. respectively.
Public Comments: Two individuals or
organizations commented on the MCLG
for simazine. One commenter
questioned the reliability of the current
animal studies for simazine if the
Agency haa to use an additional 3-fold
uncertainty factor in the calculation of
the DWEL. This commenter was also
concerned that the chemical may have
been placed in Group C (possible human
carcinogen) based on the similarity
between simazine tnd atrazine or
propazine. He claimi that the
Justification for the cancer classification
of simazine being placed in Group C
should be made solely on the basis of
animal data.
The second commenter agreed that
EPA should use the non-carcinogenic
data for establishing the MCLG for
Group C chemicals. This commenter
added that Group C contaminants are
not suitable for.the quantitative cancer
' • riskassessmenfprocess. "••' -
Several comments on the NOA were
received which discussed this issue. All
of the commentere on the NOA
supported use of the Epstein study
[Epstein et al.. 1991] and dropping the
additional 3-fold uncertainty factor.
EPA Response: In response to the first
commenter. EPA believes that the
animal studies used in the calculation of
the DWEL for simazine are adequate
studies and provide reliable information
to calculate the DWEL. The additional 3-
fold uncertainty factor was originally
applied to account for the absence of an
adequate reproduction study. As
discussed above, the 3-fold uncertainty
factor is not being used in the final
DWEL or MCLG calculation in today's
notice.
As tj this commenter's concern that
simazine should be placed in Group C
based only on animal data and not on
the similarity with atrazine or
propazine. the Agency notes that
simazine has been placed in Category II
based on the weight-of-evidence
approach and not only because of the
structure-activity relationship with
atrazine and propazine. Simazine has
been found to cause mammary gland
tumors in Sprague-Dawley rats. This
effect was also noted with other
analogues: atrazine. propazine, and
recently with cyanazine. This fact adds
to the weight-of-evidence of the
carcinogenicity of simazine in this
• animal species and supports EPA's
classification of simazine in Group C.
In response to the second
commenter's contention that all Group C
contaminants are unsuitable for
quantitative cancer risk assessment, the
Agency disagrees. In some cases,
adequate dose-response data from •
singk study may be available, even
though the weight of evidence is
inadequate for a Group B classification.
In the July 1990 proposal the Agency •
described two options for the
calculation of the MCLG for Category II
(i.e.. Group C) contaminants such aa
simazine, one using the RfD approach.
with an additional safety factor, and
-another using the cancer quantification
approach.
Many drinking water contaminants
placed in Category D have been
classified aa Group C, possible human
carcinogen, due to the limited nature of •
the weight of evidence for
carcinogenicity. For Group C. the
existing cancer risk assessment
guidelines [USEPA. 1986] allow some
flexibility as to whether to quantify the
risk. Quantification should be carried
out on a case-by-case basis, depending
on various factors, including'th*--.-
adequacy of the data.
For Group C contaminants, the MCLG
is usually based on the RfD approach
when sufficient non-carcinogenic data
are available. An additional 1- to 10-fold
safety factor is used to account for the
possible carcinogenicity. The resulting
MCLG can then be compared to the
cancer risk if the data are quantifiable.
If adequate data are not available to
determine an RfD. then the MCLG is set
at the 10'* to 10"»excess cancer risk
level where such quantification is
appropriate.
EPA under FIFRA examines the risk
for Group C contaminants like simazine
using both an RfD approach and
quantification of cancer risk using the
cancer potency. Either method may be
an appropriate method for risk
management decisions.
As noted in the July 1990 proposal,
carcinogenic potency for simazine at 1.2
X 10"' mg/kg/day"' was determined
from the incidence of mammary gland
tumors in female Sprague-Dawley rats
[McCormick et al., 1988: MRID *4O6144-
05). Based on this carcinogenic potency,
simazine concentrations of 0.003 and
0.0003 mg/1 were associated with
theoretical cancer risk levels of 10"* and
10"*, respectively.
The Agency also-has sufficient non-
carcinogenic data to determine an RfD.
Using the RfD and a 10-fold safety
factor, EPA calculated an MCLG of 0.004
mg/1. This MCLG corresponds to a
theoretical cancer risk level of 1 X 10~*.
The 10-fold safety factor used by EPA to
calculate this MCLG is justified based
on the possible cancer risk associated
with this chemical as expressed in the
rat chronic/oncogenic study
[McCormick et al., 1988; MRID #406144-
05]. Thin study was used for both the
calculation of the cancer potency based
on mammary gland tumors and the
derivation of the RfD based on a
NOAEL of 0.5 mg/kg/day for other
systemic toxicity. like the noted
reduction in the female body weight
gain and the significant changes in the
hematology parameters. This RfD is also
supported with the NOAEL of 0.7 mg/
kg/day from a one-year dietary
exposure study in the dog [McCormick
and Green. 1988; MRID #406144-02].
Using the RfD approach with an
additional safety factor, the Agency is
promulgating today an MCLG of 0.004
-------
F*dervi Register / VoL 57, No. 138 / Friday. July 17, 19&2 / Rules and Regulation* 3TT33
tng/1 for simazine assuming a daily
consumption of 2 liters of water by a 70
kilogram adult and applying a 20 percent
relative source contribution from
drinking water. This MCLG of 0.004 mg/1
corresponds to the theoretical cancer
risk level of 1 X 10"*.
1. l'2.4-Trichlorobenzene. EPA
proposed *n MCLG of 0.009 mg/1 forv
1.2.4-trichlorobenzene (TCB) in the July
1990 proposal [55 FR 30405). The MCLG
of 0.009 mg/1 was derived from a
subchronic inhalation study in rats
{Watanabe et al.. 1978). A NOAEL of
1.31 mg/kg/day and a DWEL of 0.046
mg/1 were identified, resulting in an
MCLG of 0.009 mg/1 when applying a 20
percent contribution from drinking
water.
Public Comments: In response to me
July 1990 notice, three individuals or
organizations commented on the MCLG
proposed for 1.2.4-trichlorobenzene.
Each commenter criticized EPA's use 'of
an inhalation study to derive a health
assessment value and regulatory
standard for drinking water ingestion.
EPA Response: In response to the
public comments received for the July
1990 proposal. EPA has reexamined the
database for trichlorobenzene. The
Agency agrees with the public
comments stating that in the case of
1.2,4-trichlorobenzene the oral RfD
should not be based upon the Watanabe
inhalation study [Watanabe et al., 1978).
Upon reexamination of the oral studies,
EPA determined that the Robinson et al.
(1981) study provides the best scientific
basis for determination of an RfD for
1.2.4-trichlorobenzene, as discussed in
the November 1991 Notice of
Availability [56 FR 60953]. This study
was a multi-generation reproductive
study in rats that were dosed with 0, 25.
100 and 400 ppm 1.2.4-trichlorobenzene
added to the drinking water for 95 days
per generation for two generations and
examination of the offspring of the Fi
rats. The only compound-related.
changes seen in the dams or offspring
were significant increase* in adrenal
gland weights of the Po and Ft
generations.
To more specifically characterize the
changes noted in this study, an in-house
EPA study was performed. It was found
that the increased adrenal weights were
associated with the histopathologic
lesion, vacuolization of the zona
fasciculata of the cortex. The Robinson
study determined a NOAEL at the 100.
. ppm dose (14.8 mg/kg/day). Based on
. thi* study antf applying an uncertainty
factor of 1,000 to account for sensitive
human subpopulatiotic, extrapolation
from an animal study, and for use of a
study which was lew than lifetime, the
RfD is 0.01 mg/kg/day and the DWEL is
0.35 mg/1 (verified by the RfD/RfC
Workgroup [USEPA. 1991bJ). Applying
relative source contribution of 20
percent. EPA is today promulgating an
MCLG of 0.07 mg/1 based upon the
Robinson study, as proposed in the
Notice of Availability,
EPA received two comments on the
NOA.1 both of which supported EPA't '•'
use of the Robinson study [Robinson et
al.. 1981] as the basis for the 1.2.4-
trichlorobenzene RfD and MCLG.
m. 1.1.2-Trichtoroethane. EPA
proposed an MCLG of 0.003 mg/1 for
1.1.2-trichloroethane in the July 1990
proposal [55 FR 30406]. The MCLG of
0.003 mg/1 was derived from two 90-day
drinking water studies in mice [Sanders
et al.. 1985: White et al.. 1985]. A NOAEL
value of 3.9 mg/kg/day was used to
calculate a DWEL of 0.14 mg/1. by
applying an uncertainty factor of 1.000
(per NAS/EPA guidelines for a NOAEL
derived from a less-than-lifetime study).
The proposed MCLG of 0.003 mg/1 was
calculated from the DWEL by applying
an additional safety factor of 10 because
of the classification of 1.1.2- >
trichloroethane in Group C (limited
evidence of carcinogenicity as
evidenced by the presence of
hepatocellular carcinomas and adrenal
pheochromocytomaa in mice but not
rats) and by applying 20 percent
contribution from drinking water.
Public Comments: In response to the
July 1990 notice, two individuals
commented that the use of an
uncertainty factor of 1.000 indicated that
reliable data do not exist for the
development of a DWEL. Another
commenter was confused about the use
of an extra 10-fold safety factor for a
chemical classified as a Group C
chemical and asked ifor clarification
about the use of an extra safety factor
and the rationale for its use.
EPA Response: In response to the
comments about the use of a 1.000
uncertainty factor. EPA prefers to use
data from lifetime studies to set DWELs
and MCLGs. However. EPA often
regulates chemicals that do not have a
complete data base: for example, there
may be no lifetime studies in animal
species. In such cases, an additional 10-
fold uncertainty factor is applied to
account for the "data gap." per NAS/
EPA guidelines.
As described previously in today'*
notice. EPA has developed a three-
category approach for setting MCLGs for
chemical* in drinking water. For
chemical* in Category II (compound*
having limited evidence or
carcinogenicity via drinking water), the
MCLG it usually bated on the use of the
RfD approach with an additional safety
factor of 1 to 10 to account for possible
carcinogenicity. If the data are not
sufficient to calculate an RfD, then the
MCLG is set in the 10'»to KT • lifetime
cancer risk range. Since the Agency has
verified an RfD for 1.1.2-trichloroethane
(verification date 8/01/90) [IRIS. 1991hj.
EPA has used the RfD approach with an
additional safety factor of 10 (to account-
for possible carcinogenic effects) to
derive the MCLG for 1.1.2-
trichloroethane. Based on this approach
and after consideration of public
comment. EPA is promulgating today an
MCLG of 0.003 mg/1 for 1.1.2-
trichloroethane. as proposed. This
MCLG of 0.003 mg/1 corresponds to the
theoretical cancer risk of 10' *.
n'. 2.3,7.8- Tetrachlorodibenzo-p-dioxin.
EPA proposed an MCLG of zero for
2.3.7.8-tetrachlorodibenzo-p-dioxin
(2,3.7.8-TCDD: dioxin) in the July 1990
proposal (55 FR 30384). This proposal
MCLG was based on the classification
of 2.3.7.8-TCDD in Group B2: probable
human carcinogen. New data [i.e..
Fingerhut et al.. 1991 and other studies]
have become available to EPA since the
publication of the July 1990 notice.
• Critical reviews of much of these data.
including reassessments of critical
cancer studies and new epidemiology
studies are under way but have not been
completed by the Agency to date. The
Agency is undertaking a complete
reassessment of the risks from dioxin
which includes a review of the entire
health effects data set for 2.3.7.8-TCDD .
as well as additional laboratory studies.
The Agency expects to complete its
reassessment including a full peer
review by 1993.
Until that time, the Agency believes it
is appropriate to proceed to regulate
2.3.7.8-TCDD in drinking water using the
existing health data and the current
peer-reviewed risk assessment.
Consequently, the Agency is regulating
2.3.7.8-TCDD based on the risk
assessment presented in the July 1990
proposal. Once EPA has completed its
critical review of the new health
information, the Agency will initiate a
process to determine whether the MCLG
for 2.3.7.8-TCD should be revised.
Public Comments: In response to the
notice of July 1990.12 individuals or
. organizations commented on the MCLG
proposal for 2.3.7.8-TCDD. Several
commenters believed EPA's proposed
MCLG was too stringent and several
believed the MCLG was appropriate, but
that the MCL was too lenient.
Four commenters believe that the
cancer potency of 2.3.7.8-TCDD ha*
been overstated by the Agency and
cited the re-review of the Kociba cancer
slides by the EPA Pathology Working
Group (PATHCO) as evidence [Kociba
-------
F«hrd Registtg / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
et al.. 1978J. The PATHCO'* panel of
experts found two-third* fewer tumort
than the original Kociba study, and
concluded that those found were
correlated with toxicity. suggesting a
threshold mechanism. These
commenters also indicated that the
PATHCO findings have already been
recognized by.EPA as scientifically ••
defensible since the Agency approved
the Maryland Water Quality Standard.
which relied on these findings.
One commenter staled that there is a
large body of epidemiological evidence
on 2,3.7.8-TCDD which has found no
association between dioxin and human
cancer, and that the Agency is therefore
not justified in basing all its
mathematical extrapolations on cancer
data from rat studies. This commenter
also stated that the linear multistage
model used to qualify cancer risk for
2.3.7.8-TCDD was the incorrect model
since the reexammatSon of the Kociba et
al. (1978) data indicates no linear dose
response and evidence of a threshold
cancer response.
The same commenter urged EPA to
revise the cancer potency factor based
on the most recent reexamination of the
Kociba et al. (1978) data done by the
PATHCO.
Two commenters criticized the fact
that the MCLG/MCL applies only to
2.3.7.8-TCDD. even though the Agency
acknowledges that other isomer* of
polychlonnarted dibenzo-p-dioxin
(PCDD) and polychlorinated
dibenzofurans (PCDF) have similar toxic
properties as estimated by the 2.3.7.8-
TCDD toxic equivalency factor (TEF)
methodology. The commenter claims
that the MCLG/MCL should be based on
the TEF approach.
One commenter believes that EPA's
proposal of a zero MCLG for 2,3.7,8-
TCDD is inappropriate since data
indicate that the chemical promotes
cancer through a receptor mediated
mechanism, thus indicating it is a
threshold carcinogen. The commenter
indicated that 2.3.7.8-TCDD is not a
tumor initiator but is more likely a tumor
promoter.
One commenter stated that the
average dioxin exposure among the
general population exceeds EPA's
calculated reference dose (RfD) and that
it is unacceptable for EPA to allow any
further dioxin exposure. The commenter
also stated that the Agency failed to
consider more recent data showing
adverse reproductive effects for 2.3.73-
TCDD at doses' lower than those cited in
the July 1990 proposal The commenter
claims that an up-to-date RfD would be
10 times more stringent than the RfD
cited in the July 1990 proposal. •
EPA Response: EPA disagree* with
the commenters who stated that the
MCLG for 2.3.7.8-TCDD is too stringent.
The Agency has placed this compound
in Category I and is setting the MCLG at
zero based on its carcinogenic potential.
EPA disagrees with the commenters
who alleged that EPA has already
approved- the Kociba- et at (1978) re'read-
as part of its approval of the Maryland
water quality standard for 2.3.7,8-TCDD.
Maryland did not incorporate a re-read
of the Kociba study in developing their
water quality standard for 2.3.7.8-TCDD.
Instead. Maryland used the FDA cancer
potency estimate for this contaminant.
In response to the concerns raised
about the cancer potency, EPA is
presently reviewing the cancer potency
of 2.3.7.8-TCDD as part of its complete
reassessment of dioxin. The Agency is
also investigating the mechanism of
carcinogenicity, including assessing the
likelihood of a potential threshold
mechanism and appropriateness of the
current extrapolation model. However,
at this time, the Agency has not
completed its risk assessment or
subjected it to peer review and therefore
has made no decisions to change its
assessment of the cancer potency or the
possible threshold mechanism for
dioxin. As stated above, the Agency
expects to complete its reassessment in
1993. Given this time frame and the legal
mandate to regulate 2,3.7,8-TCDD in
drinking water, the Agency has relied on
the data available at the time of the July
1990 proposal.
EPA does not agree with the
commenter who stated that there is a
large body of epidemiology data on
2.3.7,8-TCDD which has found no
association between dioxin and human
cancer. EPA stated in the July 1990
proposal that taken together, the
epidemiology studies based on exposure
to 2,3,7.8-TCDD by themselves are
inadequate to establish a relationship
between 2,3.7.8,-TCDD and the
development of tumors in humans. More
recent data, however (including
Fingerhut 1991 and studies from
Germany and Italy), are being evaluated
together with the previous epidemiology
studies a* part of the overall
reassessment of dioxin. and EPA
expects to reach its conclusion* within
the timeframe noted above.
EPA is considering revising the cancer
potency based on the re-read of tht
Kociba et al. (1978) data'and other data
such as body weight/surface area
correction*. In addition. EPA will asws*
the entire data base, including the uuuc
of threshold carcinogenicityt and • :
possible immuBotoxicity and
reproductive toxicity at low levels,
before embarking on a change in lite
cancer risk characterization. Because
dioxin is currently considered a B2
carcinogen by the Agency, the MCLG is
being set at zero.
EPA agrees that new data published
since development of the proposed
criteria document might support a
different RfD. As part of an overall . .
' reassessment of dioxin toxicity. EPA i*
reviewing studies on immunotoxicity
and reproductive effects in addition to
the cancer data. The RfD and DWEL
would become relevant to setting the
MCLG for dioxin only if it were
determined that this compound is in fact
a threshold carcinogen with a potency
so low that other non-cancer effect*
become the mo'st sensitive endpoints of
toxicity. This point will be considered in
the re-evaluation of the risk assessment
of 2.3.7.8-TCDD.
In response to the commenter who
stated that EPA should regulate all
isomers of polychlorinated dibenzo-p-
dioxin (PCDD) and polychlorinated
dibenzofurans (PCDF) using the tox'ic
equivalency factors (TEF) approach.
EPA is not considering the regulation of
other related compounds at this time.
The Agency has no indication that these
compounds are found in public water
supplies. The Agency is regulating
2,3.7,8-TCDD in today's rule because it
is the most potent isomer and it is
included in the list of 83 contaminants to
be regulated under the SOW A.
In response to the claim that EPA
should not propose an MCLG of zero for
2.3,7,8-TCDD because it is a threshold
carcinogen, the Agency's reassessment,
again, is reviewing all the health effects
data on 2.3.7,8-TCDD in an effort to
update the cancer risk characterization
of 2,3.7,8-TCDD. However, until the
Agency has completed its reassessment,
the Agency will continue to consider
2.3,7,8-TCDD to be a non-threshold
contaminant and. thus, maintain an
MCLG of zero for 2.3.7.8-TCDD. Because
the analytic limitation for drinking water
compliance monitoring for dioxin is at
30 ppq, a significant change in the risk
assessment and consequently the
MCLG, would be needed before an
increase in the final MCL would result
Detailed descriptions of 2.3.7.8-TCDD
toxicity at different dose levels and in
different animal species are documented
in the 2.3,7,8-TCDD Health Criteria
Document prepared in support of thi*
regulation [USEPA. 1988d]. Thi*
document i* available in the Drinking
Water Public Docket
Bated on the available information.
EPA is promulgating today an ViCLC of
zero for 24,7.8-TCDD,
o. Endrin, hexachlorobenzene,
oxamyL pichram. For four
-------
Federal Renter / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations 3179',
contaminants, no significant issues were
raised and no new health effects
information was obtained by the Agency
that would cause it to change the
MCLGs from the level proposed in July
1990. Therefore, for these contaminants
(endrin. hexachlorobenzene. oxamyl and
pidoram). final MCLGs are.promulgated
in today's^otice as proposed, as
presented in Table 2.
B. Establishment of MCLs
1. Methodology for Determination of
MCLs
The SDWA directs EPA to set the
MCL "as close to" the MCLG "as is
feasible." The term "feasible" means
"feasible with the use of the best
technology, treatment techniques, and
other means, which the Administrator
finds, after examination for efficacy
under field conditions and not solely
under laboratory conditions, are
available (taking costs into •
consideration)." {SDWA section
1412(b)(5)). Each National Primary
Drinking Water Regulation that
establishes an MCL lists the technology.
treatment techniques, and other means
which the Administrator finds to be
feasible for meeting the MCL (SDWA
section 1412(b)(6)).
The present statutory standard for
"best available technology" (BAT) under
1412(b)(5) represents a change from the
provision prior to 1988, which required
EPA to judge feasibility on the basis of
"best technologies generally available"
(BTGA). The 1988 Amendments to the
SDWA changed BTGA to BAT and
added the requirement that BAT must
be tested for efficacy under field
conditions, not just under laboratory
conditions. The legislative history .
explains that Congress removed the
term "generally" to assure that MCLs
"reflect the full extent of current
technology capability" [S. Rep. No. 58,
99th Cong.. 1st Sess. at 8 (1985)]. Read
together with the legislative history.
EPA has concluded that the statutory
term "best available technology" is a
broader standard than "best technology
generally available." and that this
standard allows EPA to select a
technology that is not necessarily in
widespread use. as long as its
performance has been validated in a
reliable manner. In addition. EPA
believes that the technology selected
need not necessarily have been field
. tested for each specific contaminant but
rather, that the operating conditions
may b« projected for a specific
contaminant using a field tested
technology from laboratory or pilot
systems data.
Based on the statutory directive for
setting the MCLs, EPA derives the MCLs
based on an evaluation of (1) the
availability and performance of various
technologies for removing the
contaminant, and (2] the costs of
applying those technologies. Other
technology factors that are considered .
in determining the MCL include the
ability of laboratories to measure
accurately and consistently the level of
the contaminant with available
analytical methods. For Category I
contaminants, the .Agency also
evaluates the health risks that are
associated with various levels of
contaminants, with the goal of ensuring
that the maximum risk at the MCL falls
within the 10" * to 10"' risk range that the
Agency considers protective of public
health, therefore achieving the overall
purpose of the SDWA.
EPA's initial step in deriving the MCL
is to make an engineering assessment of
technologies that are capable of
removing a contaminant from drinking
water. This assessment determines
which of those technologies are "best."
EPA reviews the available data to
determine technologies that have the
highest removal efficiencies, are
compatible with other water treatment
processes, and are not limited to a
particular geographic region.
Based on the removal capabilities of
the various technologies. EPA calculates
the level of each contaminant that is
achievable by their application to large
systems with relative clean raw water
sources. [See H.R. Rep. 1185. 93rd Cong..
2nd Sess. at 13 (1974); 132 Cong. Rec.
S6287. May 21,1988, statement of Sen.
Durenberger.J
When considering costs to control the
contaminants in thin rule, EPA analyzed
whether the technology is reasonably
affordable by regional and large
metropolitan public water systems [See
H.R. Rep. No. 93-1185 at 18 (1974) and
132 Cong. Rec. S6287 (May 21.1986)
(statement of Sen. DurenbergerJJ. EPA
also evaluated the total national
compliance costs for each contaminant
considering the number of systems that
will have to install treatment in order to
comply with the MCL. The resulting
total national costo vary depending
upon the concentration level chosen as
the MCL. The more stringent the MCL.
the greater the number of systems that
may have to Install BAT in order to
achieve compliance and the higher the
national cost In today's rule. EPA has
determined that coits for large syjtems
and total national compliance costs at
the final MCL* are reasonable.
affordable and. therefore, feasible.
One commenter urged EPA to apply
cost-effectiveness analysis in selecting
the MCLs for the contaminants m this
rule. EPA did consider the relative cost-
effectiveness of regulatory alternatives
in selecting the proposed MCLs for
radionuclides in a recent notice (July 18.
. 1991 (56 FR 33050}). In. the-radionuclides-:-:
proposal. EPA collectively analyzed the
regulated contaminants based on the
fact that all cause cancer by delivering
ionizing radiation to body tissue.
Ionizing radiation is itself classified as a
group A carcinogen. Comparing the
relative cost effectiveness of controlling
different sources of ionizing radiation
dose formed the basis for choosing the
most cost-effective alternative for
proposal in the radionuclides rule. While
EPA sought public comment on broader
• use of cost-effectiveness analysis, the
Agency did not suggest that it would be
applying a similar analysis to all other
drinking water regulations, and EPA
does not believe that cost-effectiveness
analysis should be applied to the MCL
selections in today's rule since the
factors that made this analysts
appropriate in the radionuclide proposal
radionuclides notice are not present
here.
The feasibility of setting the MCL at a
precise level is also influenced by
laboratory ability to measure the
contaminant reliably. EPA derives
practical quantitation levels (PQLs)
which reflect the level that can be
measured by good laboratories under
normal operating conditions with
specified limits of precision and
accuracy. Because compliance with the
MCL is determined by analysis with
approved analytical techniques, the
ability to analyze consistently and
accurately for a contaminant at the MCL
is important to'enforce a regulatory
standard. Thus, the feasibility of
meeting a particular level is affected by
Jhe ability of analytical methods to
determine with sufficient precision and
accuracy whether such a level is
actually being achieved. This factor is
critically important in determining the
MCL for contaminants for which EPA
sets the MCLG at zero, a number of
which by definition can be neither
measured nor attained. Limits of
analytical detection require that MCL be
• set at some level greater than the MCLG
for these contaminants. In these cases,
EPA examined the treatment capability
of BAT and the accuracy of analytical
techniques as reflected in the PQL to
establish the appropriate MCL level
EPA also evaluates the health risks
that are associated with various
contaminant levels in order to ensure
that the MCL adequately protects the
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31798 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
public health. For drinking water
contaminants. EPA sets a maximum
reference risk range of 10"' to 10"*
excess individual risk from a carcinogen
over a lifetime. This policy is consistent
with other EPA regulatory programs that
generally target 'his range using
conservative models that are not likely
to underestimate the risk-Since the •-.- ••
underlying goal of the Safe Drinking
Water Act is to protect the public from
adverse effects due to drinking water
contaminants. EPA seeks to ensure that
the health risks associated with MCLs
for carcinogenic contaminants are not
significant.
Below is a discussion of how today's
MCLs were determined, including the
Agency's response to comments on the
proposed rule.
2. Inorganic Analytical Methods
In the fi.ly 1990 notice, the Agency
proposed a list of analytical methods for
measuring the five inorganic chemicals
(lOCs) in today's ru'p. These analytical
methods are considered to be
economically and technologically
feasible for compliance monitoring. In
the November 29.1991 notice of
availability (NOA). new information
received by the Agency on these
methods was made available for public
comment. The NOA included new and
updated versions'for analytical methods.'
performance data on the proposed
methods and corrections to some of the
information included in the proposal
related to the method detection limits.
The NOA also addressed several issues
that were raised during the public
comment period for the July 1990
proposal. EPA has analyzed the
available information and has
considered the public comments on the
proposal and the NOA in arriving at the
final selection of the inorganic methods
and their associated MDLs and PQLs.
The analytical methods being
promulgated today are in some respects
revised from those proposed, as
indicated in the NOA. and as discussed
below. These methods were selected
based on the following factors: (l)
Reliability (i.e.. precision/accuracy) of
the analytical results; (2) specificity in
the presence of interferences; (3)
availability of enough equipment and
trained personnel to implement a
national monitoring program (i.e.... • ->• •••
laboratory availability); (4) rapidity of
analysis to permit routine use; and (5)
cost of analysis to water supply
systems.
Table 11 lists the analytical methods
that EPA is approving today for use to
comply with the monitoring
requirements in this rule. EPA has
updated the references to the most
recent editions of the relevant manuals.
including the atomic absorption.
emission, and mass spectrometric
methods for metals, the spectrometric
and electrode methods for cyanide.
These newer editions are generally very
similar, and in some cases identical, to
the methods proposed in the Juiy 1990
notice.
TABLE 11.—APPROVED METHODOLOGY FOR INORGANIC CONTAMINANTS AND METHOD DETECTION LIMITS (MDLs)
Method
MOL (mg/ n
Antimony ,
B«ytl«im ,.
NlCHW . .... „
Th4*i«m .....
C»arKje .....
, Atomic acsorption. Furnace _ _
' Atomic Absorption. Platform _ _ _
i CP-Mast Soectromatry v _ ... ,
HyarKJe-Atomic Absorption _
,,„. Atomic Absorption. Furnace - _ :. „
1 Atonic Absorption. Platform _ _.._
Indoctivery Coucled Plasma '
i iCP.Mais Soecuometry ,
„,.. Atonx: Absorption. Furnace , ; .
Atom* Absorption. Platform _ _ _. „ _ ,
' Inductrvety Coupled Plasm* ' _ . .
tCP'Mass Spectrometry , . .
™» Atomic Absorption. Furnace
1 Atom* Absorption, Platform
. iCP-Masa Spectromeiry _ _ _.. „
. 1 Distillation. Spectrophotometnc * _
• OistiHation. Automated. Soecvophotometnc 2
i Sefectwe Electrode '
i Distillation. Amenable. Spectrophotometnc " -...- - -
1
0003
4 Q OQOQ
0 0004
0001
0 0002
< 000002
0 0003
00003
0001
4 00006
0 005
0 0005
0001
4 00007
0 0003
002
0005
005
002
' Us«>j a 2X preconceitration step as noted in Method 200.7. Lower MDLs may be achieved when using a
-------
Federal Raster / Vol 57. No. 138 / Friday. |uly 17. 1992 / Ralei md Regulation!
these corrections. However, they had .
concerns on how the resulting
corrections would be used in the setting
of the PQLs. This issue is addressed
below in the PQL discussion.
ICP-Mass Spectrometric Method (EPA
Method 200.8)—Several commenters had
concerns.with.thelisting.of EPA.Method •
200.8 as an approved method because of
the following: (1) the absence of an
Intel-laboratory method validation study.
(2} the limited availability in
laboratories, and (3) the high acquisition
cost of the instrumentation. With
respect to the first point, the Agency
recognizes the usefulness of
interlaboratory performance data and
has recently completed an
interlaboratory method validation study
(Determination of Trace Elements in
Water by Inductively Coupled Plasma-
Mass Spectrometry: Collaborative Study
by J.E. Longbottom et aL. 1991). which
was made available for public comment
with the NOA. The resulting study data
indicate that laboratories using the ICP-
MS method are quite capable of meeting
the performance criteria (i.e.. MDL PQL
and acceptance limits) designated for
the metal contaminants in this rule. EPA
received no public comments on these
data.
With respect to the second point
regarding the limited availability of
laboratories, the Agency believes that
laboratory capability will expand with
time. Although ICP-MS is not currently
widely used. EPA expects a progressive
evolution of the technique and an
increase in its use analogous to the
development and use of another mas*
spectrometry technique, gas
chromatography/mas* spectrometry
(GC/MS). When GC/MS was first
introduced, it was considered state-or-
the-art and few labs had the expertise or
instrumentation to employ, the
technique. However, its use expanded
quite rapidly and today there are very
few laboratories that do not have the
GC/MS instrumentation and employ this
technique for routine analyses. The
change in availability of GC/MS is
attributed mostly to advantages and
benefits for multi-analyte techniques, as
discussed below. EPA believes this
trend will also occur with the ICP-MS
technique. Furthermore, this technique is
only one of many being approved for use
in the analyses of the metals in today's
rule. Laboratories with the ICP-MS
capability may.us,e it for analysis of thi
metals in this rule, and those labs
without it may use another method or
consider acquiring ICP-MS
instrumentation.
In response to the third point
regarding high acquisition costs of
instrumentation. EPA believes that
while ICP-MS represents a substantial
capital investment for labs, there are a
number of cost advantages associated
with having ICP-MS capability, i.e..
sensitivity, multiple metals analysis
capability and high volume sample
throughput. ICP.-MS is a. utable and...
precise technique capable of excellent
accuracy and very low detection limits,
thus providing a laboratory with the
option of performing multielement
analysis using one technique. Another
cost advantage can be realized when
comparing the cost of running each
individual metal analysis on an atomic
absorption spectrophotorneter versus
the cost of simultaneous multiple metals
analyses on ICP-MS. Denpite the high
initial capital cost, ICP-MS capability is
cost-effective because of the speed of
analysis it provides, thus reducing
operational costs. EPA believes that
these advantages will allow laboratories
using ICP-MS to expand their
capabilities and expertise and increase
their productivity.
In conclusion. EPA has determined
that ICP-MS is both technically and
economically feasible for routine
compliance monitoring and is
designating it as one of the approved
analytical methods for conducting
monitoring for the met a In in today's nil*.
Digestion for Metals—-Commenters to
the NOA expressed concerns about the
clarity of EPA's requirements for the us«
of the "total metals" technique and for
digestion of drinking water samples
prior to metals analysis. The
commenters noted, first, that pp. 3-5 of
Section (3030) of the seventeenth edition
of the Standard Methods for the
Examination of Water and Wastewater
[USEPA, 1383), states:
"Colorless, transparent samples
(primarily drinking water) containing a
turbidity of <1 NTU, no odor, and single
phase may be analyzed directly by
atomic absorption spectroscopy or
inductively coupled plasma
spectroscopy for total metals without
digestion*
The commenter also noted that EPA's
1983 "Method for Chemical Analysis of
Water and Waste*" (MCAWW) on page
Metals-5 states:
"Drinking water samples containing
suspended material and settleabla
material should be prepared using the
total recoverable procedure (4.1.4)
* * * .". which included a digestion
step.
The commenters believe that in light
of these statements, samples without
suspended and settleable materials may
not have to be digested The
commenters stated that they recognize
that under certain circumstances, both
digested and undigested drinking water
samples should be compared to verify
that metals are being properly
recovered.
EPA agrees that the requirements for
the use of the "total metals" technique
and for digestion of drinking water- . •;.
samples may not be clear, which could
result in different interpretations by
different analysts. In addition to the
notes above, page Metals-'i of the
"Method for Chemical Analysis of
Water and Wastes" (MCAWW) states
that:
- "While drinking waters free of
paniculate matter may be analyzed
directly, domestic and industrial wastes
require processing to solubilize
suspended material."
While digestion may be necessary for
turbid water samples. EPA does not
believe it is critical for non-turbid, clean
drinking water samples. The current
methodologies being cited for metal
analyses of drinking water samples are
applicable for samples of other matrices.
However. EPA agrees the guidance cited
above on whether to digest or not to
digest drinking water samples may not
be very clear. EPA believes that results
from analyses using the approved total
element techniques, i.e.. graphite furnace
AA and ICP. can be reported as -total
metals" for non-turbid (<1 NTU)
samples that have been properly
preserved (cone HNO» to pH <2).
because under these circumstances the
"total metals" result is equal to the
"dissolved metals", since the
concentration of the "suspended metals"
would be negligible. However, samples
containing a turbidity greater than one
(>1 NTU) even though properly
preserved, require digestion using the
total recoverable technique as defined
in the approved methods, and can be
reported as "total metals". Therefore, to
provide clarity for the "total metals"
technique and to determine whether to
digest or not to digest drinking water
samples, EPA is amending the current
requirement as footnoted in the tables of
approved methodology. The revised
footnotes will state:
* Samples that contain less than 1
NTU (nephelometric turbidity unit) and
which are properly preserved (cone
HNO3 to pH <2) may be analyzed
directly (without digestion) for total
metals; otherwise, digestion is required.
Turbidity must be measured on the
preserved samples just prior to th«
initiation of metal analysis. Whtn
digestion is required, the total
recoverable technique as defined in the.
method must be used.
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31800
Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
10 For the gaseous hydride
determination of Sb and Se, or for
determination of Hg by the cold vapor
technique, the proper digestion
" technique as defined in the method must
be followed to ensure the element is in
the proper chemical state for analyses.
EPA believes that this revision will
provide danty for "total metals"
analysis and a means for determining
whether digestion is required v\hen
performing metals analyses in this rule.
To provide consistency for all metals
analyses for drinking water samples,
EPA is also incorporating these
footnotes, when applicable, by
amending the tables of approved
methodology in § 141.23(k)(4). which
includes the metals in the January. 1991
rule, and § 141.89{a). which includes ,
lead and copper.
b. Ant'ons (cyanide ar.d sulfate]. (1).
Cyanide. In the November 29.1991
NOA. EPA addressed an issue ra-'sed in
response to the July 1990 notice stating
that although the proposed MCLG was
based on "free" cyanide, the proposed
analytical method's determine "total"
cyanide. EPA concurred with
commenters that it was appropriate to
include methods that determined
cyanide amenable to chlorination. or
"free" cyanide. For this reason, the NOA
proposed to add a methodology for
amenable cyanide to the list of
approved methods, and this notice
finalizes the addition. The "total"
cyanide methods are listed as well
because they are adequate to screen
samples for cyanide. If the "total"
cyanide levels are greater than the MCL
then analysis for "free" cyanide should
be performed to determine whether
there is an MCI exceedance. The "total"
cyanide analysis is still recommended
as an initial test because it is cheaper
than the amenable cyanide method.
There are several commenters to the
NOA who supported this action.
Several commenters had concerns
with the approval of the titrimetric
method for cyanide because of its lack
of sensitivity (detection limit of 1 mg/1)
with respect to the PQL which was
proposed to be set at 0.2 mg/1. EPA
agrees with these commenters and has
rescinded the approval of this method
and deleted it from the list of approved
methods. The spectrophotometric
method has been added to the list of
approved methods for cyanide because
this method has adequate sensitivity.
This change was indicated in Table 6 of
the NOA. Comments received by EPA
supported these revisions.
(2) Sulfate. A number of comments on
sulfate analytic methodi were received
Commenters objected to the absence of
the methylthymol blue method from the
list of approved methods and to the fact
that the "non-suppressed" column is not
stated as an acceptable option in
Method 300, an ion chroma tography
method, for sulfate analysis [USEPA.
1989dJ.
EPA agrees with the commenters that
the methylthymol blue.methodis.••-•••.
adequate. However, there are no data to
support the-use of the non-suppressed
column and the commenters submitted
no data to suppott it.
Commenters to the NOA objected to
the presence of the chloranilate method
for sulfate analysis and stated that the
chloranilate method has several
problems. They stated that the required
reagent (anhydrous chloranilate) is hard
to find and that only a single vendor
from England sells this form of the
reagent. Second, the analytical
equipment called for in the method is no
longer available from the manufacturer.
In addition. ASTM has dropped this
method from its most recent edition of
published methods and EMSL/CINN
(EPA) is considering doing this as well.
EPA agrees with the commenters on all
these points.
However, as discussed above. EPA is
deferring promulgation of a final
regulation for sulfate, and so is not
promulgating analytic methods for
sulfate in today's final rule.
c. Method detection limits and
practical quantitation levels. In the July
1990 notice, there were some
inconsistencies and errors in the listed
method detection limits (MDLs) of the
cited methodologies for some of the
inorganic contaminants. Several
commenters to the proposal and the
NOA expressed concerns with these
errors and inconsistencies. The Agency
addressed those concerns in the
November 29,1991 NOA and in this
final rule, respectively, by making the
appropriate corrections, as shown in the
NOA, and by clarifying how the MDLs
were used in setting the PQLs. as
discussed below.
EPA determines practical quantitation
levels (PQLs) for each substance for the
purpose of integrating analytical
chemistry data into regulation
development. This becomes particularly
important where MCLGs are zero or a
very low concentration, near or below
the detection limit. ThaPQL yields a
limit on measurement and identifies
specific precision and accuracy
requirements which EPA uses to
develop regulatory requirementi. At
such, PQLs are a regulatory device
rather than a standard that labs must
specifically demonstrate they can meet.
The following is a discussion of how
EPA determined the PQLs for the
inorganic contaminants in today's rule.
' The proposed PQLs in the July 1990
notice for cyanide and nickel were
determined based upon MDLs and
results from water pollution (WP)
performance evaluation (PE) data as
these data were available for
concentrations near the MCLGs. There
were-no PE data-available at the u-' f%r'
proposed MCLG levels for antimony.
beryllium and thallium. Therefore, the
proposed PQLs for these contaminants
were estimated from the respective
MDLs by using "five or ten times the
MDL" to set the PQL Only the proposed
PQL for thallium was affected by the
corrected MDLs discussed in the NOA.
Several commenters had concerns
with EPA using the "five or ten times the
MDL" to set the PQLs for antimony.
beryllium and thallium. They asserted •
that it is not feasible to measure these
contaminants at these PQLs. As
discussed in other FR notices. EPA
prefers to set PQLs based on PE data or
multi-laboratory collaborative study
data: however, when such data are not
available. EPA uses the generalized rule
of "5 to 10 limes the MDL" to set the
PQL Where data becomes available,
EPA evaluates the data to verify the
generalization or make the appropriate
change(s) dictated by the data.
EPA believes that the proposed PQLs
for the inorganic contaminants are
technologically and economically
feasible and that in general the "5 to 10
times the MDL" rule is a good estimate
of laboratory practical quantitation
capability for drinking water analyses.
This assertion has now been
corroborated by evaluations of Water
Supply (WS) performance data for the
five inorganic contaminants in today's
rule.
Several commenters to the NOA had
concerns on how the WS performance
data would be used. EPA has used the
data in setting the PQLs in this rule as it
has for most of the regulated inorganics,
as discussed below.
The final PQLs for all five inorganics
were derived from data gathered in
recent Water Supply (WS) PE studies,
using the procedure described in 54 FR
22100. May 22,1989. The use of this
procedure has been well documented.
The final acceptance limits and PQLs for
antimony, beryllium and thallium are
based on EPA and State data from
Water Supply PE studies #024-027
[USEPA. 1991dJ. These PE studies were
also evaluated to verify the earlier PE
data on which EPA based the proposed
acceptance limits and PQLs for cyanide
and nickel. The new study data, made
available for public comment in the
November 29,1991 NOA. indicated (1)
for antimony and thallium, for which
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F«dwaT Ragbtar / Vol. S7, No. 1& /'Friday. July it; 1992 / 'Rule* wuf Regulation*
two options were proposed, that their
PQLs be set at 0.006 mg/1 and 0.002 mg/
1. respectively (2) that the PQLs for
nickel and cyanide should be lowered
(the proposed PQLs for nickel and
cyanide were already at levels that were
at or below the proposed MCLGs) and
(3) that the PQL for beryllium should
remain the same as proposed;-..
The PQL procedure, described in the
aforementioned May 22.1989 notice.
generates acceptance ranges, i.e.. a
range of acceptable variation in the
analytical results compared to the
known or "true" value. The acceptance
limits for the inorganics in today's rule
were generated using the procedure
"used to derive PQLs and the laboratory
performance data generated in Water
Supply Studies 24-27, which were
discussed in the NOA. The PQLs were
set at a concentration where it was
estimated that at least 75 percent of the
EPA and State labs are within the
specified acceptance ranges. The final
acceptance limits (1) are tighter than
proposed for cyanide. (2) are bated on
the data rather than two standard
deviations for antimony, beryllium and
thallium and (3) remained the same for
nickel as proposed. The resulting PQLs
and acceptance limits are shown in
Table 12.
TABLE 12.—INORGANIC CONTAMMANT Ao
CEPTANCE LIMITS AND PRACTICAL
O.UANTITATION LEVELS
Inorganic
contaminant
Antimony
Beryl bum
CyarwJe
Nickel
Thallium
MCL
(mg/1)
0006
0.004
02
0 1
0002
Acceptance
limits (plus
or tnnjt %
of the true
value)
30
15
25
15
30
POL
(mg/1)
0000
0.001
0 1
001
0002
preservation, containers and holding
times listed in Table 13 were proposed
for the inorganic contaminants in this
rule. One commenter on the NOA
mentioned that the addition of 0.6 gram
of ascorbic acid in the preservation of
cyanide is not applicable to all samples.
and that the specific procedure in the .. •
methods should be followed to ' '
determine the measure of ascorbic acid
required. EPA agrees with the
commenter and has amended the table
accordingly.
No other comments were received on
these requirements. Therefore, the
Agency is promulgating these
requirements today, as listed.
d. Inorganic chemical sample
preservation, container, and holding
times. The requirements for sample
TABLE 13.—INORGANIC CONTAMINANT SAMPLE PRESERVATION, CONTAINER, AND HOLDING TIME REQUIREMENTS
Contarruneot
Antimony.— — __._
Cyarw)6
Nickel
ThaHtum ._._
Preservative '
Cone HNO> to pH < 2 ~ --,..,-.. .-,., .,-,,,., ._. __. —._._...
Cone HNOi to pH <2 ...
Cool 4'C NaOH to pH >124 . _
Cone HNOi topH <2- .
Go«eHNQi to p* <"!.-. ...... ,.„....-,...... - ~
Container*
PorQ
PorG
PorQ
PorG
PorQ
Manmom hotdng time • •
emonttw.
6 month*.
14 days.
6 jikmBa.
' Samptes mat cannot be aod preserved at me tome o< collection became o4 sampbng limitations or transportation restrictions should be acidified with ratnc
acid to a pH <2 upon recast n me laboratory. Following acidification, ffw sampM snoutd be held lor 16 noun betor* withdrawing an «*quot tor sample processing
and/or anaiys*.
" P «= plastic, hart or soft G - glaaa, hart or soft
* In all cases, samples snook] be analyzed as soon after collection us posstte.
* Ascot*: aod should onty be uSed in the presence at residue! cMome.
3. Organic Analytical Methods
A minimum of eight of the 17 methods
included in today's rule are needed to
measure the IB organic contaminants
(Table 14). Eleven methods have been in
use or promulgated in other rules; there
were no significant comments on them.
Four methods are single-analyte
methods (i.e.. they measure only one
analyte). Most systems will conduct
compliance monitoring for contaminants
to which they are vulnerable using one
of the volatile organic chemical (VOC)
methods and one to three other
methods—Methods 515.1.525.1 and
531.1—all of which may be used to
measure the organic contaminants
regulated in two previous rules
promulgated on July 8.1987 [52 FR
25690] and January 30,1991 [56 FR 3520].
Some commenter* asked that when
EPA permits flexibility in method
selection by citing more than one
method for a contaminant, that the
detection limit practical quantitation
limit (PQL) and maximum contaminant
limit (MCL) be set differently for each
method; EPA disagrees. Although
method detection limits (MDLs) as
calculated by the procedure* in 40 CFR
130. appendix B may sometimes differ
for an analyte measured with different
methods, for regulatory purpose* EPA
must set a single PQL and MCL Sine*
laboratories can sometimes achieve
lower MDLs than thosa cited for •
specific listed method. EPA believes that
a laboratory which routinely achieves
the detection limits specified for a
contaminant (Table 14). should be
permitted to use that method for
compliance monitoring.
EPA also received comments
recommending the use of alternate
analytical procedures. Because reliable
compliance data are necessary for
enforcement of the regulations. EPA
continues to cite only methodologies
included in EPA regulations, as
summarized in the guidance contained
in the laboratory certification manual.
However. EPA recognizes that
improvements in analytical technology
may occur frequently. Thus, the Agency
is developing a regulatory process to
expfriite the revision and updating of
older methods and the inclusion of new
methods for drinking water compliance
ana'y sis.
-------
. > . i ..'-..
31802 Federal RggUter / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
TABLE 14.—ANALYTICAL METHODS, DETECTION LIMITS. MDLs. PQLs. MCLs AND MCLGs FOR ORGANIC CHEMICALS
EPA memod No,
Contaminant
MDL
POL
1 All concentrations a'e >n mg/1
-Memoo 1613 [USEPA. 19901],
• AN 500 Level Met-ocs fu'SEPA. !988e ana USEPA. 1990k]
MCL
5021 5022,524 1,5242 . . ...
KZ 2 503 1. 524 2
S021 5022 52« 1 52*2 ,.
'6»3*
525 1 550, 5=0 « ...
SIS 525.)
5C6 525 I .
505 509. 525 *
505 508 525 t
505 525 I
505 507 5251
5*5 .
515 I ., . .... .
515'
S3« 1 ......
547
548 . ,„,..., ,.
543 * .
Dtcnforometnane
1. 2. <»-TricniofoDenrene
1.1. 2-Tncmoroemane
2 3. 7. 8-TCDD lOioxm)
. ,. Benzo ia) pyr«ne .
-.. Oi 12-ewiyinetyi) «ioit«..: :
Di (2-einymexyi) pmtiaiate
Enonn
HexacmorooenzBnc
Hexacniorocyciopemaaiene
. . .. ... .... Simazine . .
.... Daiapon
. Dinoset) .
Picloram
Oxamyl iVyoate)
. Glyphosate _
Enaotnail
Oiquat .
. 00002
. . 00003
00001
5 - 10 ' .
. . 0 00002.
. . . 0.0006 '
00006
000001
00001
00001
000007
0001
00002 :
0.0001 '
0002 i
0 006 :
: -6.009 •
00004 .
0005 :
0.005
0005 •
3 • 10 •
00002 :
0.006 '
0006
0001
0001
0001
00007 •
001 .
0002
0001
002
006
009
0004
0005
007
0005 '
3 • 10 •
00002 .
04
0006
0002
0001
005
0004
02 •
0007
05
02
07 •
0 1
002
0 07
0003
04
0002
Q OS
0004
02
0007
05
02
07
0 1
002
a, Me&od-speafic comments. Some
comments were received on individual
chemicals--phthalates. adipates. 2.3.7.8-
TCDD(dio.xm). dalapon.
dichloromethane. endothall and
polynudear aromatic hydrocarbons
(PAHs)—and on certain methods being
approved for drinking water regulations
for !he first time—Methods 506. 547. 548.
549. 550. 550.1. 513 and 1613 [USEPA.
1988e and 1990k|.
Several commenters believe that not
enough laboratories will be certified to
timely conduct compliance monitoring
analyses: EPA disagrees. These
comments were similar to those raised
and answered in 56 FR 3550 in the rule
promulgated on January 30.1991. EPA
also received a comment on the NOA
(56 FR 60949] about the effect of starting
the monitoring on January 1.1993 rather
than January 1.1996. EPA recognizes
that an earlier compliance monitoring
start-date accelerates the need for
certification. EPA also believes there is
some confusion about the criteria for
obtaining laboratory certification.
EPA acknowledges that fewer
laboratories currently are proficient
with some of the single-analyte methods
and the 2.3.7.8-TCDD Method 1613 than
with older pesticide and volatile organic
chemical methods. These same concerns
were raised by commenters when EPA
included newer methods in the rule
promulgated January 30.1991. EPA again
expects systems to use vulnerability
assessments as a cost affective way to
characterize trends in their water
quality and thereby be eligible for
renewable monitoring waivers. For
these and other reasons stated in the
1991 rule (56 FR 3550) EPA believes an
adequate number of laboratories will
have opportunity to obtain certification
or^jrovisional certification for these
contaminants in today's rule.
Some commenters were concerned
that high background contamination or
interferences would make reliable
detection and precise measurement of
adipates. phthalates and
dichloromethane difficult or impossible
at the detection and MCL concentrations
listed in the July 1990 notice. They
believe that many false positives for
dichloromethane. in particular, would
occur due to ambient air conditions in
the laboratory or sample collection site.
All EPA methods detailed careful
procedures that must be followed to.
minimize or eliminate interferences or
contamination that can occur in sample
collection, shipment, storage and
analysis. In EPA's laboratory
performance evaluation studies more
than 75 percent of the laboratories have
routinely and successfully analyzed
samples with dichloromethane at
concentrations near the practical
quantification level of 0.005 mg/1. This
affirms that laboratories appear to be
taking precautionary steps outlined in
the methods.
Based on public comment and further
testing. EPA has modified Method 508
for the analysis of adipates and
phthalates. EPA switched from ternary
solvent mixture to the binary methytene
chloride and hexane solvent mixture.
which is used in a previously
promulgated EPA method! EPA Method
606. Using this modification, a very good
precision of ±6 percent was obtained in
replicate'measurements at
concentrations near the practical
quantification level.
EPA acknowledges that methods can
often be improved and the Agency
works to refine them and to adopt new
analytic technology and techniques. For
example. EPA's Environmental
Monitoring Systems Laboratory in
Cincinnati is working to change
derivatization procedures that use' '
diazomethane forthe measurement of
several chemicals, including dalapon.
Dalapon is now measured with Method
515.1. EPA plans to include dalapon in
the next version of Method 552. which
will be named 552.1. Method 552.1
replaces diazomethane with acidic
methanol in the derivatization step, and
liquid-liquid extraction is replaced by
liquid-solid extraction. This should
reduce interferences and improve the
precision of the analysis.
EPA also plans to change the
procedure (Method 548) for
measurement of endothall. The new
method would be named Method 548.1.
It would replace
pentafluorophenylhydrazine with acidic
methanol in the derivatization step, and
liquid-solid extraction is used. The
electron capture detector is replaced
with a flame ionization detector in the
new method. Data arid method write-ups
were not available in time for these
methods (552.1 and 546.1) to be included
in today's rulemaking. However. EPA
anticipates adopting these methods for
compliance monitoring of dalapon and
endothall as soon as possible after they
are released by the Environmental
Monitoring Systems Laboratory.
An early success is EPA Method 1613.
which is a consolidated method for the
measurement of 2,3,7.8-TCDD (dioxin) in
all matrices. It replaces Method 513.
which had. been cited in the July 25,1990
proposal and as the method for
monitoring dioxin as an unregulated
contaminant in the rule promulgated
January 30.1991 [56 FR 3592,
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/ VoL 57. No. 13ft / Friday, July 17. 1992 / Rules and Regulation*
31893
1141.40(n)(ll)]. This rule promulgate!
its use only for drinking water. Its use in
other media will be promulgated as part
of the appropriate regulations.
EPA agrees with commenters who
•fated that only one polynuclear
aromatic hydrocarbon (PAH),
benzo(a)pyrene. should be regulated at
this time (see earlier discussion in':
Section III-4). Three analytical methods
were proposed in the July 1990 notice for
the measurement of benzo(a)pyrene.
Method 550 and 550.1 use high pressure
liquid chromatography (HPLC). Method
525 uses a gas chromatograph connected
-to a mass spectrometer. No significant
, -comments were received on these
methods. Methods 550 and 550.1 are
included in today's rule for compliance
analyses [USEPA. 1990k]. :
Several commenters asked for more
mass spectrometer methods to increase
the number of analytes in an analysis
and to decrease the probability of
interferences that can cause false
positives. EPA proposed multi-analyte
mass spectrometric Method 525 in the
July 25.1990 proposal. As discussed in
an earlier Federal Register notice (58 FR
30272, July'l. 1991), EPA improved the
method, renumbered and adopted it as
Method 525.1. Because Method 525.1
supersedes Method 525. EPA is adopting
525.1 for seven organic chemicals in
today's rule.
Method 525.1 has the potential to
measure a large number of organic
chemicals; the question is whether-the
required sensitivity can be achieved. As
always, laboratories using this method
(and other methods) for compliance
analysis must demonstrate an ability to
achieve the detection limits specified in
.Section 141.24 using the procedure
described in 40 CFR part 136, appendix
.B.
Some commenters requested that EPA
consolidate methods across all EPA
programs and in all media. EPA realizes
the difficulty laboratories may have in
conducting certified analyses for the
same organic chemical in several
matrices over a wide range of
concentrations using similar yet
different EPA methods. Through EPA't
Environmental Methods Management
Council. EPA is working to consolidate
methods, performance requirements and
definitions of quantitation and
detection. Regulatory, quality assurance,
- enforcement and other issues make this
a complicated task.
b. Responses to comments specific to
. Method 1613 for dioxin. EPA hat
received comments related to the
application of Method 1613 to the
measurement of chlorinated dioxins end
furans in drinking water. Some of these
comments address a narrow range of
issues, primarily the Method Detection
Limit (MDL) and practical quantitation
limit (PQL). Others are very extensive in
that nearly every aspect of the technical
details in Method 1613 are addressed. In
organizing its response to the comments
submitted, the Agency has responded to
general issues first, then to comments
specific to the technical details of
Method 1613.
Some comments on Method 1613
overall are incorporated into these
comment replies. Many commenters
were concerned about the performance
of Method 1613 on sample matrices
other than drinking water, particularly
on treated and untreated industrial
wastewaters. paper pulp, and sludge
from wastewater treatment processes.
EPA stated in the proposal of this rule
(55 FR 30426] that Method 1613 was
developed for-these matrices. In 1991
EPA proposed Method 1613 for analysis
of these matrices by industrial
discharges under the Clean Water Act
(proposed amendment to 40 CFR part
136 in 56 FR 5090. February 7.1991), and
solicited comments on that proposal. To
date. EPA has not responded to the
comments received on that proposal.
Because EPA desires to move quickly on
today's drinking water rule, EPA is
responding to comments on Method 1613
related to application of the method to
drinking water prior to responding to
comments on the February 7.1991
proposal of Method 1613.
General issues concerning Method
1613. A commenter noted that Method
1613 has not been promulgated. EPA
agrees. As mentioned above. EPA
proposed Method 1613 under section
304(h) of the FWPCA at 40 CFR part 136
on February 7,1991, accepted comments
at that time, and has not promulgated
Method 1613 in part 138 as of today's
date. EPA has used data from its studies
of Method 1613 to support the practical
quantitation limit (PQL). the Method
Detection Limit (MDL), and other
technical aspects of the regulation of
dioxin in drinking water, in the same
way that EPA references other
documents in support of its rules. The
Agency is not required to use
promulgated methods for reference
purposes. • •
A commenter stated that EPA Office
of Water Method 1613 and Office of
Solid Waste SW-^646 Method 8290 are
significantly different, contradicting
• recommendations to Congress in the
report titled "Availability, Adequacy
and Comparability of Testing
Procedures for the Analysis of
Pollutants Established Under section
304{h) of the Federal Water Pollution
Control Act" (USEPA, 1988f]. The
commenter provided a block diagram
showing differences in these two
methods. EPA agrees that the two
methods are different in exact technical
detail, but the measurement principle of
the two methods is the same. In
developing testing methods for its
regulatory programs, such methods
evolve at different rates for different . .
purposes. For example. Method 1613 '
was originally developed primarily for
use in treated and untreated effluents.
but is applicable to pulps, sludges.
drinking water and other solid and semi-
solid matrices. Similarly. EPA Method
6290 was developed for use primarily in
solid and semi-solid matrices, but is
applicable to analysis of water. EPA is
in the process of consolidating methods
for dioxin measurement in air. water.
and solid waste, consistent with the
recommendations in the report that the
'commenter references. However, such a
merger cannot take precedence over
EPA's development of methods to meet
specific program heeds and for
regulatory programs with Congressional
deadlines and court-ordered timetables.
A commenter stated that, although
EPA used Method 1613A for analysis of
more than 500 samples, there have been
many versions of this method and the
data produced using these versions were
inaccurate. EPA acknowledges that
some data produced with early versions
of Method 1613 may have been less
accurate than data produced with more
recent versions. Much of these earlier
data were developed using complex
matrices, such as industrial effluents,
and were generated as the method was
being developed. The method and MDL
proposed in the November 1991 notice,
and being finalized here, are based not
on these early data but on later data
generated using reagent water, which is
a matrix more similar to drinking water.
The accuracy of analytic methods
usually improves with experience in
using the method. However, the fact that
data become more accurate as a
function of time does not mean that
earlier data are necessarily unsuitable
for their intended purpose. The Agency
is careful to consider in its rulemaking
the effects of the variability of the
analytical data. For example, in this
rulemaking. data variability is
accounted for in the determination of
the MDL and is considered in setting
the PQL.
A commenter noted that Method 181J
calls for instrument calibration to be
verified at a high level, but that
calibration should be verified instead at
the minimum level because of
uncertainties at that level. EPA
disagrees that calibration should be
verified at the minimum level. In method
-------
31804 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
1613, calibration it verified at the mid-
point of the analytical range. This
verification is common and accepted
practice for analytical methods (see e.g..
the methods in 40 CFR 136. appendix A).
The generally accepted practice
followed by EPA is to verify calibration
in a region where error is a constant.
proportion, of the level being measured.
This may not be the case if calibration
were done at the minimum level.
A commenter stated that the MDL
tes's for Method 1613 use reagent water
for tests of initial precision and recovery
(1PR) and on-going precision and
recovery (OPR). and that this practice is
inappropriate for methods that must rely
on extensive cleanup. Reagent water is
water in which the analyte(s) of interest
and interfering compounds are not
detected by the method being used. EPA
disagrees that reagent water is
inappropriate for the IPR. OPR. and
other tests. EPA believes that in the case
of dioxin in drinking water, reagent
water and dnnking water are nearly
equivalent matrices, in that the
concentrations of potentially interfering
compounds in drinking-water are
extremely low.
A commenter stated that allowing the
analyst the flexibility to modify the
method may adversely affect method
performance on real world samples, and
cited as examples that the performance
test solution used to evaluate the
particular columns in Method 1613 will
not work with other columns, and that
reducing the solvent volumes to elute
the dioxm from the AX-21 cleanup
column would prevent analysts from
meeting the detection limits specified in
the method. EPA disagrees. In
developing and promulgating the 40 CFR
part 136. appendix A methods. EPA has .
received comments in the past similar to
this one that the methods should allow
no flexibility in procedures [49 FR
432461. EPA also received comments
that there should be great leeway to
modify the methods [49 FR 43245). EPA'i
general response to those comments and
to this comment is that flexibility is
permitted only in discretionary elements
of the test procedures, and that the dad
generated must meet all stated
performance criteria.
For the specific examples that the
commenter cited. EPA believes that the
requirement for an alternate gas
chromatographic column to meet not
only the specifications for the
performance test solution but also to
meet the relative retention time criteria
in Method 1613 effectively preclude*
any column with Inferior performance,
and that reducing the solvent volumes
used with the AX-21 column to the point
where native dioxin becomes non-
detectable would probably cause the
recovery of the labeled compounds to
fall below the recovery specifications in
the Method: therefore, this would not be
allowed.
EPA notes that the objective of
permitting flexibility»in certain ••'
discretionary parts of its "methods is to
allow for improvements in technology
while requiring all performance
specifications in the method to be met.
A ccmmenter included with its
comments approximately 40 pages of
suggested technical modifications of
Method 1613 to improve the reliability of
the Method. EPA appreciates these
suggestions. This commenter has
participated in EPA's validation studies.
has conducted validation studies of its
own. has scrutinized the details of
Method 1613 and other EPA methods.
and has provided many valuable
suggestions for improvements to these
methods. EPA has considered all of
these suggestions, as well as the
suggestions of others, in its continuing
evolution and upgrading of analytical
methods, and shall continue to work
with all interested parties to assure that
these methods are as state-of-the-art as
possible. Many of the suggestions relate
to analyses of more complex non-
drinking water matrices and are not
relative to analysis of drinking water
samples.
1613 Inter-laboratory study. A
commenter said that EPA had not
completed its inter-laboratory study of
Method 1613 at time of proposal of the
drinking water regulation for dioxin, and
that EPA is premature in proposing
Method 1613 without validating it first.
EPA has relied only on the MDL studies
on Method 1613 in determining the MDL
and the PQL Inter-laboratory validation
studies are on-going and EPA will make
them public when complete. However,
EPA is not required by statute or policy
to use inter-laboratory data to establish
MDLa or PQLs.
Two commenters stated that EPA's
inter-laboratory study used extracts of
samples but not real-world sample*.
Both commenters are correct However.
this rule relies on an MDL study as the
basis for the PQL. and not the inter-
laboratory studies. Therefore, this ii not
a relevant issue for this rule. EPA used
extracts of real-world sample* because
the shipment of large volume* of dioxin-
contatning water both intra- and inter-
nationally was deemed to be too great a
risk to human health and th«
environment and because of the
difficulty in producing a homogeneous
mixtur* of dioxins In such large weter
volume*. EPA underttand* the
commenters' argument and concerns
that performing an inter-laboratory
study on extracts of water rather than
water itself could possibly result in less
bias and greater precision than if water
had been used, but EPA believes that
the risk of using raw waste water
samples'-was-unacceptable: EPA'has
recently collected and received a large
volume of data on application of Method
1613 to paper industry wastewater and
believes that the matrix effects
associated with extraction of dioxin
from water are fairly well quantified at
this point. EPA believes that its
international inter-laboratory validation
study will be valuable in assessing
method and laboratory performance.
even though the study will not be
conducted on raw wastewater.
However, the complex matrix effects
these data are intended to identify and
help resolve are not relevant to drinking
water samples.
SDS extraction. A commenter stated
that the Soxhlet/Dean-Stark (SDS)
extraction procedure for solids has only
been tested to a limited extent on one
municipal sludge.- The commenter was
correct at the time of this comment in
that EPA had performed limited testing
of the SDS extraction procedure on a
limited number of samples. Since that
time, EPA and others have extracted
many sample* using the SDS technique.
and although some data show that some
of the higher isomer* and congener* of
dioxin may not be extracted as
efficiently as other extraction
techniques. EPA has not confirmed the*e
results. However, SDS extraction is not
a method that would be used on
drinking water samples, and so this
comment is not relevant to the present
rulemaking.
A commenter noted that use of liquid-
solid extraction using 3M"» Empon Disk
is approved by EPA for Method 525.1,
and ia included in dioxin Method 513.
The commenter suggested that EPA
include the option of using the Empore
Disk in Method 1613. EPA i* currently
evaluating the Empore disk a* «n
extraction device for cqueou* sample*
.in Method 1613. EPA'* Environmental
Monitoring Systems Laboratory in
Cincinnati. Ohio (EMSL-Ci) has
performed extensive testing of liquid-
solid extraction devices. EPA will
.continue to study the Empore disk and
similar device* because of their
potential for reducing solvent use in the
laboratory, and will incorporate such
devices into Method 1613 and other EPA
methodu if the performance of the*e
device* 1* demonstrated to be
equivalent to extraction device*
presently In these method*. Nationwide
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Fadarii Rggiftef / Vol. 57. No. 13d / Friday. July 17. 1992 / Rules and Regulation 31005
application for an alternate test
procedure may be made under 40 CFR
138.5.
Labeled compound recovery. A
commenter stated that recovery of
labeled compounds in Method 1613 do
not adequately correct for incomplete
recovery of the native analytes.because
it is nearly impossible to spike the
labeled compound into the sample in
such a fashion that it distributes itself
identically to the native anaiyte. EPA
has chosen the isotope dilution
technique for quantification because it is
the most precise analytic technique
currently available to measure dioxin.
• EPA is aware that in some instances the
labeled compounds are not distributed
identically to the native analytes. but
believes that the advantages of the
isotope dilution technique far outweigh
any limited imprecision and reduced
accuracy that may occur when external
standard quantitation techniques are
used. Nearly all analytical methods for
dioxin employ isotope dilution to
provide the highest accuracy and
greatest precision.
Method Detection Limit (MDL) and
minimum level. A com.menter stated
that Method Detection Limits (MDL's) of
5 and 10 ppq for Methods 1613 and 513.
respectively, have not been
demonstrated and that it is not possible
for even the best laboratories to attain
the MDL developed by EPA. EPA
disagrees. EPA has now demonstrated
that the MDL = 5 ppq using Method
1613, as described in the NOA.
A commenter stated that the proposed
standard for dioxin is based upon
detection limits associated with .
outmoded analytical methods that are
thousands of times less sensitive than
the most advanced methods available.
that methods developed by Christoffer
' Rappe, University of Umea, Sweden are
capable of detecting TCDD at 0.001-
0.020 ppq in drinking water, and that •
Canadian methods achieve MDL's of 2
ppq in pulp mill effluents and could be
extended to achieve 0.2 ppq in drinking
.water. EPA is aware that it is possible to
achieve lower detection limits by
revising the dioxin methods to use
sample volumes 10 to 1,000 times (or
more) larger than the existing methods.
At present, most dioxin methods employ
a one liter sample. This sample is
shipped from field locations to
laboratories that have HRGC/HRMS
instruments. Samples will need to
' continue to be shipped from remote
V locations to laboratories. Most sample
shipments are by overnight courier 10
that the samples can be maintained
refrigerated froth the time of collection
until extraction. Shipping 10 to 1.000
liters presents unique logistics problems
and is prohibitively costly (a 1.000 liter
sample weighs approximately 2.500 Ibs..
and costs $1.50/lb. to ship for a total of
$4.500 per sample). Also, while large
volume samples might theoretically
result in a lower MDL, increased
interferences are likely.to result EPA is.
aware of no data demonstrating that
lower MDLs may be achievable. An
alternative would be to collect the
samples on a liquid-solid extraction
device at the remote location and ship
the device to the laboratory. However.
EPA has not developed or validated this
sampling means at this time. EPA is
aware of the methods proposed for
regulatory use in Canada, and believes
that the improvements in sensitivity
suggested by the commenter are simply
the result of differences in terminology
and reporting practices. The Canadian
methods use the term "MDL" to mean
the sample-specific detection limit that
is calculated solely on the basis of
signal-to-noise measurements. In
contrast. EPA uses the term MDL to
refer to the statistically determined
value that results from replicate
measurements, as described in 40 CFR
part 136. appendix B. EPA will continue
to study devices and procedures for
lowering the detection limit to levels
commensurate with the Agency's
measurement and regulatory needs.
1613 Method Detection Limit (MDL}
study. A commenter utated that the 5
ppq MDL in Method 1613 was calculated
from a single-shot experiment that does
not represent a real work estimate of the
MDL It alleges that a real world
estimate of the MDL is at least 10 ppq
based on the 104 mill study and an
estimate by Georgia-Pacific. EPA agrees
that the MDL in Method 1613 was
obtained by a single use of the MDL
procedure [40 CFR part 136. appendix BJ.
As described in the proposal of Method
1613. the MDL procedure was followed
as prescribed, with a result of 5 ppq.
EPA has reviewed the data submitted by
the contract laboratory that performed
the MDL procedure and believes that the
tests were performed properly and that
the 5 ppq MDL is valid. EPA believes
that if the MDL procedure were
performed in other qualified
laboratories, similar results would be
obtained using Method 1613. although
some laboratories might obtain slightly
higher or slightly 'lower results.
However, the MDL is by definition a
single laboratory single operator
concept EPA is unaware of any samples
in the 104 Mill study that were analyzed
at least seven time*, or that conformed
to other requirements of the procedure
for determining the MDL The
commenter provided no specific data for
analysis. Moreover, the 104 Mill study
analyses concern pulp, sludge and
industrial wastewater matrices and so
the MDL derived in that study is not
necessarily the lowest that could be
obtained in samples that more closely
resemble drinking-w.ater,matrices.:••..:'• •<:
Two commenters daim that the MDL'
study cited was conducted with'reagent
water and. therefore, the MDL study is
not relevant. As EPA stated in its
response above to the use of reagent
water for initial and on-going precision
and recovery and other quality control
tests. EPA believes that in the case of
dioxin in drinking water, reagent water
and drinking water are nearly
equivalent matrices, in that the
concentrations of potentially interfering
compounds in drinking water are
extremely low.
A commenter said,that no data are
presented in the Federal Register notice
[56 FR 5090] other than for reagent
water. Therefore, the proposed minimum
levels for solid matrices are
insupportable. For the purpose of the.
regulation of dioxin in drinking water.
data on matrices other than on reagent
water or drinking water are
unnecessary.
A commenter said that the MDL
experiment is inappropriate due to the
high spike levels chosen for the study.
that the variability increases as the
concentration levels approach the MDL
and that the only way to truly determine
the MDL is to perform the experiment at
the exact level of the MDL. EPA notes
that the 25 ppq level was chosen as
described in EPA's proposal of Method
1613 [56 FR 5095). As stated earlier. EPA
believes that its contract laboratory
followed the MDL procedure correctly.
including the use of 25 ppq as the
spiking level. EPA agrees that the
variability increases as the
concentration levels approach the MDL.
However, one of the tenets of the
concept of the MDL is that the
relationship between the level and the
standard deviation of the measurement
becomes approximately constant in the
region of the MDL and the spiking level
is not critical in this region. In addition.
EPA believes that spiking at too high a
. level will tend to overestimate the MDL
rather than underestimate it. EPA is also
in the process of contracting for
additional MDL studies in a variety of
matrices and at other spiking levels
appropriate to the matrices. These data
will be made available at a later date.
Two commenters stated that it is well
' known that a break in the calibration
curve occura at approximately 5 ppq.
Consequently extrapolation from 25 or
-------
31806 Fscteral Ragbter / Vol. 57. No. 138 / Friday. July 17^992 / Rules and Regulation*
12 ppq to 5 ppq is not technically valid.
Extrapolation must be made at or below
the break point. One of the commenters
stated further that extrapolation of the
instrument calibration far beyond
demonstrated performance is not sound
science and provided a graph showing
relative standard deviations a function
of corresponding effluent.concentration-
for native dioxin m calibration
standards. EPA agrees that calibration
error increases as concentration levels
approach the MDL but believes that the
measurement of the MDL in Method
i613 was made in a valid region of the
calibration curve and was made
according to the MDL procedure, as
detailed in the proposal of Method 1613
|56 FR 5035] and the support documents
for the NOA. EPA has reviewed the
graph provided by the commenter and
boheves that the graoh supports the
vji:<:ity of an MDL of 5 ppq. The graph
shows data points at equivalent
concentrations of approximately 3. 5.12.
100.1.000 and 5.000 ppq. associated with
relative standard deviations of
approximately 16. 8. T. 5. 2 and 1
percent, respectively. Calculating the
relame standard deviation (RSD) of
these vaLes results in standard
deviations of 0 48.0.40. 0.84. 5. 20. and
100 ppg. respectively, for the
concentrations. Assuming that the RSD's
are the result of three replicate
determinations, the Student's t
multiplier used in the MDL procedure is
6.97. resulting in MDL values of 3.4. 2.8,
5,9. 35,140. and 700 ppq. (If more than
three replicates were used, the MDL
values would be lower). These data
clearly show that in the region of the
MDL (2-10 ppq). the MDL is
approximately constant, but rises
rapidly as the spike level increases.
Thus, the use of a high spike level would
tend to overstate the MDL. the opposite
of what is argued by the commenters.
Further, the data provided clearly show
that measurement can be made in the
range of 5 ppq because data were
reported in (his range.
Two commenters stated that dioxin
was not detected in one of seven
replicates in EPA's test of the MDL for
Method 1613. EPA believes that in EPA'g
studies of the MDL for Method 1613.
EPA's contract laboratory performed the
study improperly in its first attempt. In
this attempt, the laboratory spiked the
native analytes into the blank that was
a part of the quality control associated
with the MDL test. Also, aa pointed but
by the commentei*, the laboratory failed
to detect dioxin in one of the seven
replicates. EPA rejected the data from
this MDL study, and had the laboratory
determine the MDL under the controlled
conditions that EPA requires. The MDL
of 5 ppq that EPA state* for Method 1613
is the result of the properly conducted
study. EPA did not formally release the
results of the improperly conducted
study, but has made all results of all
studies available to all interested
parties.
•, •' MDL/POL-issues^''Acommenler said' "
that the lowest level that can be
measured is the.PQL. EPA disagrees.
EPA has demonstrated that
measurements can be made as low as
the MDL, but has defined the concept of
the PQL as the lowest Jevel that can be
reliably achieved within specified limits
of precision and accuracy during routine
laboratory operating conditions (50 FR
46902J. Thus, the PQL provides an
allowance for the degree of
measurement precision and accuracy
that EPA estimates can be achieved
across laboratories. If EPA desires a
level of measurement precision and
accuracy that is high, the PQL is set
slightly higher (on the order of 10 times
the MDL); whereas if the Agency desires
a slightly lesser level of measurement
precision and accuracy (in exchange for
reduced health risks). EPA will set the
PQL level somewhat lower (on the order
of 5 times the MDL). but EPA believes
that measurements can be made in the
range between the PQL and MDL.
A commenter stated that finalization
of the PQL should await completion of
an appropriately designed inter-
laboratory study because the PQL is
intended to reflect performance of
multiple laboratories. The commenter
also noted that the preferred method of
determining the PQL would be to utilize
performance evaluation data from as
many labs as possible. EPA believes
that inter-laboratory studies, whether
method validation or performance
evaluation, are useful in establishing the
PQL but also believes that a multiplier
of 5 -10 times me MDL is an effective-
way to establish the PQL. In estimating
the PQL, EPA takes into consideration
all data available, including single
laboratory, multi-laboratory,
performance evaluation, and other data,
as well as regulatory needs to protect
human health and the environment. In
the regulation of dioxin in drinking
water. EPA has reviewed the data from
its study of Method 1613, as well as data
submitted by c«mmenter>. EPA has
established the PQL for this rule after a
review of technical data from method
studies and from health risk
considerations.
A commenter said that decreasing the
PQL from 50 ppq to 30 ppq represents «
very slight decrease in the level of risk
that does not justify the drastic increase
in the level of uncertainty that would
occur. EPA disagree, that there i« a
drastic increase in the level of
uncertainty between 50 and 30 ppq. As
the data submitted by the commenter
demonstrate, the uncertainty
attributable to calibration increases
from approximately six percent Jo. 4
approximately seven percent when the
level decreases from the equivalent of 50
to 30 ppq.
A commenter stated that it is a
longstanding practice within the
scientific community to use a 3-fold
multiplier in establishing the limit of
quantitation. The American Chemical
Society (ACS) uses the concepts of the
Limit of Detection (LOD) and Limit of
Quantitation (LOQ) in discussions of the
lower limits of analytical'measurements.
The LOD is approximately equivalent to
EPA's MDL and the LOQ is
approximately 3.3 times the MDL As
EPA has stated in previous discussions
of the PQL (50 FR 46902). the MDL and
LOQ are single laboratory concepts.
whereas the PQL is the lowest level that
can be reliably achieved within
specified limits of precision and
accuracy during routine laboratory
operating conditions. EPA uses a
multiplier of 5 to 10 times the MDL as
well as other factors to establish the
PQL EPA is presently in the process of
reviewing its approach to establishing
the limits of analytic chemistry for
drinking water samples and the use of
this information in setting drinking
water standards. EPA may propose
revisions to its general approach in a
later Federal Register notice. The ACS
concepts are'among those that will be
considered in this process. EPA will
review its MCLs at that time to
determine whether revisions are
appropriate.
A commenter stated that the PQL
should be set at 10 times the MDL since
the carcinogenic risks do not justify less
precision in dioxin measurement. As
EPA has noted in response to other
comments. EPA hat set the PQL at
approximately five times the MDL based
on technical and health risk
considerations. The PQL is a regulatory
tool that may include consideration of
health risk. EPA also reiterates that the
precision of the dioxin measurement is
not significantly degraded between 50
and 30 ppq.
c. Detection and quantitation levels:
laboratory performance criteria. Many
comments were received on EPA'i
procedures for determining MDL§ and
PQLs. Calculation of method detection
limits (MDLi) by procedures Ml forth at
40 CFR Part 138 Append?*. B i«
understood and generally accepted by i
-------
ST. No. 138 /
July 17. 19« / Rule* «nd Regri«tk»n»
the laboratory community. A few
cotnmenten wrote that since Mine
MDLs cited in EPA methods are a one
time determination by one analyst the
results may not generally be achievable
by the number of laboratories needed to
handle compliance monitoring on a
routine basis. EPA believes that
laboratory performance improves'** an-r
analysis progresses from being novel to
routine. The purpose of the PQL concept
is to allow for this inter-laboratory
variability and ensure that the majority
of good laboratories can adequately
measure contaminants, EPA has also
provided relief for most contaminants in
today's rule by permitting performance
evaluation samples to be judged by the
results of the group of laboratories
participating in each study rather than
on an absolute scale (Le. the pass
criteria are two standard deviations
from the average result rather than
within a fixed ±:percentage of the
spiked concentration).
The selection of practical'quantitation
levels (PQLs) has been discussed at 55
FR 30370 and references therein. EPA
received comments on PQLs identical or
similar to those received and responded
to in earlier rules [55 FR 30370, and 56
FR 3547-3552 and 30269-30271]. Some
commenters on the July 1990 proposal
wrote that some PQLs were too low for
most laboratories to quantify a
contaminant .with acceptable precision
because EPA relied too much on
performance by the "best" laboratories
in setting the PQLs. Some commenters
objected to the PQL for dioxin that WM
proposed at five times the method
detection limit They suggested all PQLs
be ten or more time* the MDL even if
this required that a maximum
contaminant level (MCL) be increased;
EPA disagrees. EPA recognizes that use
of a five-fold multiplier, rather than ten-
fold, may result in some loss of precision
and accuracy in performing analyses.
However. EPA believes it is sometimes
appropriate te- accept somewhat greater
imprecision and. inaccuracy when
necessary to achieve health risks within
EPA'? target risk range. EPA makes such
judgments on a case-by-case basis.
Other commenten stated that some
PQLs were too high, especially for
contaminants with xero or very low
maximum contaminant level goals.
These commenters nuggested that PQLs
and MCLs could be lowered
significantly to reduce risk, thereby
allowing only the best laboratories to
perform compliance analysis. However.
EPA believes this is impractical, due to
the large number of compliance samples
that are required to be analyzed by
these rules.
In response to this interest in
detection and quantitation levels. EPA.
the American Chemical Society (ACS)
and the American Society for Testing
and Materials (ASTM) are working on
standard definition:) of analytical
detection and quantitation levels for
chemical analyses in any matrix The
definitions, if adopted by EPA. would be
only a part of the process used to
determine the feasibility of measuring a
contaminant with acceptable precision
at the MCL The Agency is also
developing criteria to define what data
should be collected to set
interiaboratory performance standards.
EPA has determined, however, that it
is appropriate to set PQLs for today's,.
contaminants using the procedures •
.discussed in the proposal (55 FR 30370
and references therein) rather than
waiting for the results of the new
definitions. The maximum contaminant
level goal (MCLG) for several of the
organic chemicals in today's rule is
significantly greater than the MDL listed
for each contaminant in the EPA
methods. This means setting MCLs
equal to MCLG does not pose the same
problem as when reliable detection and
quantification is desirable near or below
MDLs.
For sixteen regulated organic
chemicals in today's rule, the PQLs are
based on laboratory performance data.
As discussed earlier, considerable
variation in interiaboratory performance
was observed. For this reason, the PQLs
for benzo(a)pyrene and 2. 3,7.8-TCDD
are respectively estimated at ten times
and five times the method detection
limit (as defined at 40 CFR part 136.
appendix B). Table 15 lists MCLs, PQLs
and laboratory acceptance limits for
each organic contaminant. The ranges of
concentrations included in EPA's
laboratory performance samples are
also listed
TABLE 15.—MCLs, PQLs AND ACCEPTANCE LIMITS DirrERMtNeo FROM LABORATORY PERFOPMANCS STUDIES
Contvnrw*
O (2-*ttryfrie*yn a<*c*tft
EfxJrm .— ....-—
2.3.7.8-TCOO (Dwxm)
MCLoW
0.07
0.005
0.0002
0.2
0.005
0.4
0.008
0.007
0.02
0.1
0.002
0.7
0.001
0.05
a*
o.s
O.CO4
3X1I3-*
POL
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31806 Federal Regutar / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulation*
cotnmenters that the performance by the
current pool of laboratories does not
warrant setting pass/fail criteria within
fixed plus or minus percentage limits of
the true concentration and acceptance
limits for the other organic contaminants
in today's rule remain at :r2 standard
deviations. EPA disagrees with the
comment tha: regulation be delayed.
unul fixed acceptance ranges can be
determined by interlaboratory
performance. EPA believes performance
will improve as laboratories routinely
use a method to maintain certification
for compliance monitoring analyses. The
new methods are based on the same
basic analytic techniques as many
existing methods (such as GC. GC-MS,
HPLC). EPA's experience in applying
these techniques to other analytes has
been that laboratory proficiency
improves as laboratories become more
experienced with the basic technique
and specific individual methods.
Although the data are insufficient to
change the proposed certification
acceptance limits, they are sufficient to
examine the relationship between study-
generated PQLs and PQLs calculated by
multiplying MDLs by a factor. In today's
rule. EPA has set PQLs for 16 organic
contaminants after considering an
analysis of the performance from EPA-
sponsored laboratory studies and MDL
data. In most cases the PQLs are ten
times the MDL. For four contaminants.
the PE data were adequate for
establishing the PQLs. For the
remainder. PQLs were established on
the generalization of 10 times the MDL.
For many of these contaminants, a
limited number of laboratories
participated in the PE studies, and EPA
therefore believes these data do not
adequately represent likely performance
over time. For other cases, while there
were a considerable number of
laboratories participating, the
regression-derived acceptance limits
were broad (> =50%). and the PQL was
based on 10 times the MDL, with
acceptance limits set at ±2 standard
deviations, to allow for improvement in
the future. EPA found that federal and
Stale laboratories, which were more
experienced with the methods
performed better. EPA therefore
believes the other laboratories'
performance will improve over time and
use of 10 times the MDL to set the PQL
is appropriate.
For dioxin (PQL=5 MDL) and
benzo(a]pyrene (PQL=10 MDL). PQLs -
could not be derived from an analysis of
the limited laboratory performance
database. The commenter correctly
notes that in most studies.
benzo(a)pyrene was not tested near the
final maximum contaminant level of
0.0002 mg/1. However, in the November
29.1991 notice and in today's rule. EPA
discusses a two-laboratory study of this
contaminant. The precision obtained in
samples spiked at 0.0002 mg/1 was
excellent—±6 percent or better. A
similar study, which is discussed in
today's rule..fordioxin using Method.-.-.
1613 was conducted with good results.
Thus, the PQL for dioxin and
benzo(a)pyrene-are today specified
respectively as five and ten times the
MDL.
The final PQLs for di(2-
ethylhexyljadipate and di(2-
ethylhexyl)phthalate are set at ten times
the MDL. This is consistent with EPA's
general guidelines that calculated PQLs
be equal to five to ten times the MDL.
The commenter refers to the relatively
poor performance in some of EPA's cited
studies. However, in the November 29,
1991 notice and in today's rule. EPA
discusses an improvement in the
Method 506 eluant mixture, which has
been tested in samples spiked near the
final maximum contaminant levels. EPA
believes these data warrant setting a
PQL at ten times the MDL.
EPA notes that PQLs that are'based
on an evaluation of the concentration at
which about 75 percent of the
laboratories participating in a study can
successfully analyze a sample use a
criterion that is more stringent than
setting a pass criterion of ±2 std. dev.
Using this approach, the final PQLs for
volatile organic chemicals are very close
to ten times the MDL. This is consistent
with the performance observed with
other regulated volatile organic
chemicals, all of which can be measured
in the.same sample by an identical
analytical procedure. Since analyses for
dioxin. pesticides and other organic
chemicals in today's rule use several
different analytical techniques. EPA
expected laboratory performance would
be less homogeneous than for the VOC
chemicals, which used the now-routine
purge and trap method. Use of study-
dependent laboratory criteria is
consistent with the requirement to
achieve the lowest feasible MCL
EPA disagrees that performance
sample data need to be normally
distributed in order to proceed with a
determination of the suitability of a
method for compliance measurements. It
is not practical or necessary to
benchmark interlaboratory performance
on anything but a standard matrix. Each
analytical method notes if and how the
analyst should check a compliance
sample or laboratory reagents for
possible interferences. As discussed in
today's rule, the available data indicate
that laboratories have done so even
with potentially difficult analytes such
as dichloromethane.
EPA agrees with the comment that
when analytical variability poses a
problem, the system should have the
opportunity to use multiple samples and
average the results. EPA's monitoring •
requirements-already proVide this'relief:
The requirements permit confirmation of
sample results, and the elimination (with
State concurrence) of spurious
analytical results. And more than one
confirmation sample may be taken. •
provided the State concurs.
EPA notes that for most of the
analytes presented in the table with
relatively high confidence intervals, the
PQLs and MDLs are significantly less
than the final MCLGs and MCLs. so
imprecision of the analysis is not as
likely to lead to resource-wasting false
positives.
The PQLs for most of the
contaminants are identical to the PQLs
proposed on July 25,1990. The PQL for 2.
3. 7, 8-TCDD decreased based on an
evaluation of data from an
interlaboratory study that used Method
1613. The data were cited and discussed
(56 FR 60952-60953) in the November 29.
1991 notice of availability.
For the reasons cited elsewhere in this
rule and in the July 25.1990 proposal [55
FR 30416). the final MCLG for 2. 3. 7. 8-
TCDD (dioxin) remains at zero mg/1.
and the final PQL is estimated as five.
rather than 10. times'the MDL As
discussed in the November 29,1991
notice. MDLs of 6xlO"9 mg/1 and
4xiO"» mg/1 were obtained with a
precision of ±12% in an EPA-sponsored
study. Considering the zero MCLG. the
high relative health risk, and the low
probability of occurrence in finished
drinking water, the final PQL has been
set at five times the average of the two
MDLs. The average MDL is 5x10'* mg/
1—five times this MDL is 2.5 xlO"^ mg/1.
which rounded up becomes the final
PQL of 3 X 10-« mg/1. The final MDL is
50% lower than the proposed MDL of
10X10-" mg/1. The final PQL'for dioxin
is 40% less than the proposed PQL of
5x10-* mg/1.
The important use of laboratory
performance data is to help EPA set
fixed ranges of ± acceptance limits
(Table 15) for laboratories to obtain and
maintain certification. For fourteen of
the organics covered by today's notice.
EPA has set the acceptance limits for
certification samples at two standard
deviations based on performance
sample study statistics rather than
defining fixed acceptance limits.
These limits will permit a reasonable
number of laboratories to obtain
-------
'•certification for compliance monitoring
analyses while ensuring continued
progress toward more efficient analysis.
Laboratory performance data for the
remaining five organic contaminants
were obtained in the following studies.
which were also cited in the November
29.1991 notice. In the first study, the
lowest concentration of benzo(a)pyrene -
tested in an EMSL study was 0.002 mg/L
which is ten times greater than the
proposed MCL Rather than extrapolate '
these data, two EPA laboratories tested
Method 550 for benzo(a)pyrene at the
proposed MCL of 0.0002 mg/1 [USEPA.
1991c]. They achieved a very good
precision of ±6 percent or better. The
second study concluded that the
precision for adipate and phthalate
analysis with Method 506 was relatively
poor in EMSL PE studies [USEPA,
1991c]. With the solvent changes
discussed in Section III-B-3a. an EMSL
laboratory obtained very good precision
of ±6 percent or better in samples
spiked near the MCLs. Based on these
results EPA is citing Methods 506. 550
and 550.1 as compliance methods in
today's rule, and is permitting individual
performance evaluation sample study
statistics to determine the acceptance
limits (ranges) by setting them at two
standard deviations around the average
concentration (Table 15).
For endrin and the volatile organic
chemicals, an analysis of laboratory
performance evaluation data, the mort •
recent of which were cited in the
November 29,1991 NOA. affirm* that
laboratory performance warrants using
fixed limits of ±30 percent for endrin.
The data also support using the fixed
acceptance limits of ±40 percent for
three volatile organic chemical*
included in today's rule—
dichloromethaoe. 1.2,4-trichlorobenzene
and 1.1.2-trichloroethane, These are the
same limits listed in TaUe 18 of the July
25.1990 notice.
Several commenters on the NOA data
for the SOC contaminants expressed
concern about broad confidence
intervals (near ±100 percent) and slated
doubts about PQLs based on such wide
bands. EPA agrees that the data for
some contaminants stowed broad
acceptance bands, and for too**
contaminants. EPA has established
acceptance limits as ±2 standard
deviations of the data developed in PE
studies. As laboratory performance with
• these method* improves, si is EPA'*
expenence with new methods, tfa* .
, confidence interral* will narrow,
*' 4. Laboratory certification. Several
cormnenter* expressed concern about
the resources seeded and the time ,
constrain!* to achieve fuO certification
prior to the initial monitoring period lot
newly regulated contaminants. EPA
understands that certification for all
parameters in time to comply with the
initial monitoring deadlines
(specifically, the January 1993-^
December 1995 period in today's rule)
may present some difficulties in some
areas. To alleviate this. EPA is
recommending that Su» te» and -Regions'•. •
grant provisional certification, but only
for recently regulated unalytes. The
provisional certification criteria are not
regulatory in nature. Guidelines for
granting provisional certification are
described in EPA's "Manual for the
Certification of Laboratories Analyzing
Drinking Water" (USEPA. 1990mJ.
States and Regions are encouraged to
begin certifying laboratories for analytes
as soon as MCLs and certification
requirements for those analytes have
been promulgated. It in not necessary to
wait for MCL* to become effective.or for
the State or Region to become certified.
Under the Certification Manual a State
is to grant a laboratory provisional
certification only for newly regulated
analytes until the next regularly
scheduled on-site audit after the
effective date of the MCLs or until the
end of the first monitoring period.
whichever comes first. Also, according
to the Certification Manual in order to
be granted provisional certification a
laboratory should currently be certified
to test for other drinking water
parameters, pas* an annual performance
evaluation cample containing the
analytes of interest aiad meet all the
other criteria stated in the rule. States
may add additional requirements that
they deem appropriate. In addition.
States may set criteri« for certifying a
laboratory for the measurement of
dioxin (2J^3-TCDD) with EPA Method
1613.
EPA wishes to clarify the effective
date of promulgated analytical method*
in this rule. A promulgated method or
method update must be used for those
analytes for which it was promulgated
as soon as the MCLs become effective.
which i* usually 18 months after
promulgation. However, the method*
may and should be uced starting 30 days
after promulgation of the rule* for
analyzing sample*. Thi* will enable
laboratories to be well prepared and at
least provisionally certified when the
MCLs and monitoring requirements
become effective.
5. Selection of Best Available
Technology
a. Inorganics. On Jtily 25,1990, EPA
proposed the best available technolog**
(BATs) for the removal of tie five
inorganic contaminants frosa drinking
water (55 FR 30416). Today's notice
finalize* the*e determinations. Table 16
summarizes the final BATs for the five
inorganic contaminants.
TABLE 16.—FINAL BAT FOR INORGANIC
CONTAMINANTS
Contvmwnt
j
BAT-
Antimony ......... ______ ...
Berytkuni .. ___________ ...
Cyanide ................ - ........
Thallium „
...I C/F; RO.
.... AA; IE; BO: LS. C/F
.... IE. RO: CH.
...' IE. RO: LS.
...; AA: IE.
1 Best AvadabM Technology (BAT):
AA » Activated Alumina.
IE = ton Eichange.
LS - Lime So«er»ng.
RO « Reverse Osmosis.
•C/F m Coagulation/FtNralion.
CH.» CMonne Oadaaon.
The BATs presented in this notice are
the same as in the proposal with one
exception: ion exchange for cyanide
removal is amended to require pH
adjustment for better removal efficiency.
This issue is discussed below in further
detail with the discussions of the other
major concerns expressed during the
public comment period for Jie proposed
rule regarding the BATs for the IOC*.
(1) BAT field demonstrations. Several
commenters stated that the proposed
BATs have not been demonstrated
specifically for some of the inorganic
contaminants under field conditions.
These commenters were concerned that
the reliance upon bench-scale and pilot-
scale data in the absence of field studies
might not meet the requirements of BAT
for these contaminants under section
1412(b){5)ofrheSLTWA.
The Agency does not believe that the
SDWA requires field studies as a
prerequisite to establishing BAT for a
contaminant. The SDWA directs EPA to
set the MCL as dose to the MCLG as
"feasible." The SDWA defines
"feasible" as "feasible with the use of
the best technology which the
Administrator finds, after examination
for efficacy under field conditions and
not solely under laboratory conditions.
(is] available (taking costs into
consideration)." Section 1412{b)(3){D).
EPA interprets this provision to require
field trials for a technology, not for the
application of that technology to each
individual contaminant Consequently,
EPA has not required full-scale field
validation of a technology's feasibility
for treating a specific contaminant if its
effectivene** has been demonstrated at
bench or pilot *cale for that compound.
The technology, however. mu»t
reasonably b« expected to perform in •
similar """«<** nnAar Ocid condition*
regardleas of aberrations du* to tcale-u
factors.
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3111ft
..ftd«t«M9g«ter
57: «o.
Jdy 17. 1992 / Ruieff and Regulations
It should also be noted that many of
the 83 contaminants for which Congress
required EPA to establish NPDWRs by
June 19.1989 had never been regulated
by EPA or treated by public water
systems. Thus for many of the
contaminants which Congress required
EPA to regulate, the data which the
commenter asserts are a prerequisite to
selecting a. technology as BAT do notyet
exist. The commenter's arguments
suggest that Congress required EPA to
regulate many new contaminants within
3 years of the 1986 amendments but
effectively precluded EPA from selecting
any technologies as BAT for the
regulations. Therefore. EPA believes it is
appropriate to consider pilot plant and
laboratory studies to project the removal
efficiencies for these inorganics that
would be achieved by technologies that
have been in full-scale use by public
water systems for other similar
contaminants. A detailed discussion of
the efficiencies of each of the treatments
can be found in the July 1990 proposal
and in the "Technology and Costs for
the Removal of Phase V Inorganic
Contaminants from Potable Water
Sources" [USEPA. 1990b].
While some of the treatments listed as
BATs in Table 16 are not currently in
full-scale use to treat specifically for the
inorganic contaminants in today's
notice, they are demonstrated
technologies currently in use to treat a
variety of drinking water contaminants,
including previously regulated inorganic
contaminants. Further, in each case.
high quality bench- or pilot-scale data
obtained under verifiable conditions
which replicate typical drinking water
treatment conditions have been
provided.These data confirm that'the
treatment efficiencies of these
technologies are high and that these
technologies may be properly
designated as BAT for the inorganic
contaminants.
(2) Potential For antimony leaching
from tin/antimony solder. Several
commenters were concerned that
antimony could leach from tin/antimony
solder joints similar to lead leaching
from lead/tin solder joints.
EPA has determined that antimony
leaching from tin/antimony solder does
not present a contamination problem.
EPA has based this determination'upon
a theoretical analysis of the potential for
leaching and on three studies that
investigated antimony levels in water in
contact with tin/antimony-soldered
copper pipe joints [Herrera et al., 1981,
Subramanian et al., 1991. and USEPA.
1988a].
When different types of metals are in
contact with each other. gaJvanic
corrosion can occur. In a galvanic
couple, one metal will serve as the
anode, which will deteriorate, and the
other metal will serve as the cathode.
For copper pipes soldered with either
lead/tin solder or tin/antimony solder.
three galvanic couples can exist. For
lead/tin-soldered copper pipe joints, the
three couples which exist are: copper-
tin, copper-lead, and lead-tin. The
• strongest galvanic couple:of these three--
will be the copper-lead couple and lead
will serve as'the sacrificial anode. Thus.
galvanic corrosion would promote lead
leaching from a lead/tin-soldered
copper plumbing joint. For the tin/
antimony-soldered copper pipe joint, the
three couples which may exist are:
copper-antimony, copper-tin, and tin-
antimony. The strongest galvanic couple
of these three will be the copper-tin
couple and tin will serve as the
sacrificial anode. Thus, galvanic
corrosion would promote tin leaching.
rather than antimony leaching, from a
tin/antimony-soldered copper pipe joint
and very little antimony would be
expected to leach. In addition, tin can be
passivated by tin oxide, which could
form a passivating film to further inhibit
antimony leaching from a tin/antimony
solder joint.
Laboratory experiments and field
tests were conducted to verify the
theory on the potential for antimony
leaching from tin/antimony solder joints
(Seattle Distribution System Corrosion
Control Study: Volume III. Potential for
Drinking Water Contamination from
Tin/Antimony Solder prepared by
Herrera et al. for USEPA (August, 1981)
[Seattle. 1981] and also reported in
Herrera et al.. Journal of the American
Water Works Association, July 1982)
[Herrera et al.. 1982].
The laboratory experiments evaluated
antimony levels from tin/antimony-
soldered copper coupons with
stagnation times between one-half hour
to 98 hours. Two coupons of pure
antimony were also tested with a
stagnation time of 70 hours for
comparative purposes. The coupon tests
demonstrated that antimony dissolution
was several orders of magnitude lower
than the dissolution from pure antimony
metal even though the stagnation time
was longer (98 hours versus 70 hours).
The highest antimony concentration
observed in the tin/antimony coupon
testing was 3.7 fig/1, which is below the
MCLG promulgated in this noticed for
antimony. In addition.'tin oxides were
found adhering to areas on the solder,
which'may provide additional inhibition
of antimony leaching from tin/antimony
solder.
Field tests were conducted at the
University of Washington where tin/
antimony solder has been used for
building plumbing systems since 1968.
Samples (0.9 liter) were taken at the
point where the distribution system
entered the building to obtain the
characteristics of the inflow water.
Several commenters stated that these
were the only type of samples taken and
claimed that the study did not evaluate
the leaching potential of .the plumbing.., -
However, overnight standing samples
(0.9 liter) were taken at the tap located
the furthest distance from the entry
point to the building. The plumbing
systems ranged from 1 to 10 years in
age. Thus, the contribution of antimony
leaching from tin/antimony soldered
copper pipe joints was evaluated by
comparing the results from the ovemighi
tap sampling with the building inflow
sampling results. A difference in
antimony concentrations between the
overnight tap sample and the building,
inflow sample was observed in only one
of the eight buildings where sampling
was conducted. The concentration of
antimony in that overnight tap sample
was below the MCLG. AH of the other
antimony concentrations were below
the detection limit. In addition, tin oxide '
films were found on three solder joints
which were removed from a building's
plumbing system. These films could
have contributed to the inhibition of
antimony leaching from these joints
[Herrera et al., 1981].
The commenters noted that the study
conducted at the University of
Washington evaluated only one type of
water quality. However. Seattle's
finished water quality, at the time of this
study, was corrosive, yet significant
antimony leaching from tin/antimony
solder was not observed under these
conditions. In fact, all of the antimony
concentrations measured in this study
were below the MCLG and most were
below the detection limit. The amount of
antimony leaching from tin/antimony
solder would be even less in non-
corrosive waters.
This was confirmed by another study
which evaluated the impact of several
water qualities on antimony leaching
from tin/antimony solder with various.
stagnation times (Impact of Lead and
Other Metallic Solders on Water
Quality, prepared by Murrell for USEPA.
July, 1988) [USEPA. 1988a]. In this study,
a pipe loop was constructed with tin/
antimony-soldered joints to evaluate the
effect of water quality or antimony
leaching from tin/antimony solder. Four
waters with the following
characteristics were evaluated with
varying stagnation times to determine
their effect on antimony leaching from
tin/aMfirnony solder (1) pH between 5.1
and 5.3; (2) pH between 6.3 and 6.6; (3)
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Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
pH 7.4; and (4) pH between 8.5 and 8.6.
The stagnation times evaluated in this
study were 4 hours. 8 hours. 12 hours. 24
hours, and 4 weeks. Six samples were
taken at each pH and stagnation time
combination.
For the two higher pH ranges, where
the pH was above.pH7.0.all of the,
samples had antimony concentrations
below 4 fig/1 for stagnation times up to
24 hours. All of the samples for the
lowest pH range also had antimony
concentrations below 4 /xg/1 for
stagnation times up to 24 hours. For the
second lowest pH range (pH between
6.3 and 6.6). results at 4 ng/\ and above
were observed at stagnation times
below 24 hours. One of the six samples
with a stagnation time of 12 hours
exceeded the final MCLG and three of
the six samples with a 24-hour
stagnation time exceeded the MCLG.
However. EPA believes that systems
with such a low pH would likely fail.to
meet the requirements of the recently
promulgated lead and copper rule (June
7.1991. Federal Register [56 FR 26460]).
Those systems would therefore likely
need to increase the pH of the finished
water to comply with that regulation.
Finished water with a pH above pH 7
did not produce antimony
concentrations above the MCLG in this
study and this water quality is a likely
minimum necessary to comply with the
lead and copper rule.
EPA also believes that this study
addresses several commenters' concerns
about antimony leaching from newly
soldered joints. The commenters
apparently believe that antimony
leaching from tin/antimony solder could
be similar to lead leaching from lead/tin
solder and thus were concerned that
significant concentrations of antimony
could leach from newly soldered joints.
As discussed above, antimony leaching
from newly soldered joints was not
observed in non-acidic waters which
will predominate as systems comply
with the lead and copper rule
requirements.
The effect of water quality on
antimony leaching from tin/antimony
solder was also investigated in
Subramanian, Conner and Meranger.
Journal of Environmental Science and
Health, 1991 [Subramanian et aL 1991].
This study investigated the effect of
three water qualities on metals leaching
from four non-lead-based solders. The
amount of metals leaching from newly
"soldered joints was evaluated using high
purity, tap, and well water samples with
various standing times. The pH of the
high-purity water was 6.8. The pH and
alkalinity of the tap water was 7.8 and
30 mg/1 (as CaCOj). The pH and
alkalinity of the well water was 8.1 and
155 mg/1 (as CaCOa).
The amount of antimony leached into
samples was at or below the detection
limit of 1.2 mg/1 for standing times up to
7 days, regardless of the water quality.
For the high-purity and well water
samples, there was.nodetectable ...
leaching of antimony with standing
times longer than 7 days. However, the
amount of antimony leached into tap
water after 14. 28. and 90 days of
contact was 2.0. 3.7. and 7.3 Mg/l-
respectively. EPA does not believe that
such unusually long standing times are
typically encountered in public water
supplies. Thus, this study supports
EPA's position that antimony leaching'
from tin/antimony solder joints should '
not be a problem.
(3) Disposal of wash brines from ion
exchange and reverse osmosis
treatments in water-scarce areas.
Commenters expressed concerns
regarding the potential costs associated
with disposal of wastes (particularly
brine wastes) generated by treatment
processes which remove inorganics. Of
particular concern are waste brines
generated by reverse osmosis (RO) and
ion exchange (IE] processes. One
commenter expressed concern about the
environmental impacts as well as the
potential impact of waste water
treatment on water conservation
concerns in water-scarce regions. For
example, reverse osmosis results in loss
of a percentage of the influent water as
brine.
EPA does not agree with the
commenter's assertion that
environmental impacts (discussed
below) would be extreme if a low
sulfate standard (i.e., 400 mg/1) were
promulgated. The Agency believes that
water wastage could be minimized by
treating only a portion of source water
containing elevated sulfate levels.
blending the treated water with source
water, and by further treating brine
wastes. Waste volume reduction and
waste handling options appear not to
have been fully considered by
commenters. Other very conservative
assumptions were employed by the
commenter which led to conclusions not
shared by EPA. The commenter'o
assumptions include: An increase in
Colorado River,sulfate levels beyond
recent historical levels: and the overall^
importance of that source to the
Southern California supplier, when
competing entitlements to that river
source may diminish the supplier's share
of available river water.
One commenter stated that there are
potential economic impacts where
limited disposal option* exist The
Agency agrees with the commentei
cheaper options (such as direct
discharge into a receiving body of
water) are not always available. F<
these reasons. EPA has included se
waste treatment and waste dispose
options in its analysis and incorpot
costs for all projected systems in tb
Regulatory Impact Analysis (RIAf
Document developed for this rule
[USEPA. 1992d]. These costs are a
substantial part of the overall estin
treatment costs for meeting the drit
water MCLs.
Commenters raised questions ab
competition for scarce water in cer
regions, the need for source water
protection measures (i.e.. pollution
prevention), and waste quantity an
quality that may limit disposal opti
EPA has addressed these concerns
this rulemaking and in previous act
(Federal Register. Vol. 56. No. 20. p;
3553-3554) and does not believe the
data and assertions presented in
response to the July 1990 proposal <
sufficient to raise regulatory concet
(4) Alkaline chlorination treatme
cyanide. Several commenters were
concerned about the potential for
increased concentration of
trihalomethanes resulting from the
alkaline chlorination treatment for
cyanide. For systems whose raw w
has a high trihalomethane formatio
potential. EPA agrees that this trea'
could exacerbate the problem. How
systems can choose to install ion
exchange or reverse osmosis, whicl
would be less likely to significantly
increase trihalomethanes. As statec
the proposal, the highest observed
occurrence level for cyanide in drin
water (8 fig/1) is considerably lowe
than the MCL for cyanide (200 ^g/l
Therefore. EPA expects that few. if
systems would need to install treat!
for cyanide and that increased
trihalomethanes resulting from a
cyanide BAT is unlikely to be a
widespread problem.
(5) Ion exchange as BA Tfor cyan
Several commenters stated that ani
exchange would not remove cyanid
because at the near-neutral pH vah
for most drinking waters, cyanide is
much more likely to be present as f-
rather than CM. EPA agrees with th
commenters' assertions that anion
exchange would only likely remove
cyanide that is present as CN. EPA
believes, however, that systems tha
need to can increase the pH of theit
water to further dissociate HCN to i
The ion exchange data presented in
Technology and Cost Document ind
that ion exchange can efficiently rei
dissociated cyanide [USEPA. 1990b
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J3812 Fedend Regbter / Vol. 57. No. 138 / Friday. July 17. 1992 / Rule* and
Cyanide is dissociated at lower pH
levels than those cited in some of the
, studies in the Technology and Cost
Document. EPA has provided the
treatment costs for pH adjustment (see
Lead and Copper in Drinking Water as a
Result of Corrosion: Evaluation of
Occurrence. Cost and Technology. 1991-
IUSEPA. 1991aj). An option for systems
using ion exchange for cyanide removal
would be to adjust the pH to dissociate
and remove the cyanide and then lower
the pH somewhat prior to chlorination
and distribution. EPA believes this
approach to be a more effective way to
address cyanide removal in waters with
significant trihalomethanes (THM)
formation potential than alkaline
chlonnation. Nevertheless, for the
reasons provided in the discussion of
alkaline chlorination. EPA does not
believe (hat increased trihalomethanes
resulting from a cyanide BAT will be a •
widespread problem when using that
method.
(6) Sulfate reverse osmosis costs.
Several commenters questioned why the
total treatment costs for sulfate removal
by reverse osmosis were lower than the
total treatment costs for the inorganic
contaminants in this rule. The MCLs
proposed for sulfate were several orders
of magnitude higher than the MCLs for
the inorganic contaminants in this rule.
EPA assumed that systems would blend
a treated portion and an untreated
portion to reduce the total production
costs for sulfate. EPA believes that only
in extreme cases would systems require
both high removal efficiency and
treatment of the entire influent flow.
Thus, systems were only assumed to
treat a part of the product water to
remove sulfate rather than the entire
product flow as is assumed in the T*C
document for the other inorganic
contaminants. However, as was noted in
the Juiy 1990 proposal, blending to
reduce total treatment costs is an option'
tor systems using RO for the other lOCi.
Since a smaller volume of water is being
treated, capital costs and operation and
maintenance costs would be lower.
resulting in lower treatment costs than
estimated.
(7) Sulfate ion exchange costs. Several
commenters questioned why the total
production costs for sulfate removal by
anion exchange were higher than the
total production costs for cyanide
removal by anion exchange. The
difference in the total production coatt
for these two inorganic contaminant*
resulted from higher operation and
maintenance costi for sulfate removal
associated with resin regeneration. The
increased regeneration co«ti are due to
faster saturation if the r«in b«cau«« of
the significantly higher levels of sulfate
that would be treated to meet the
proposed MCL levels compared to the
levels of cyanide.
b. Synthetic organic contaminant.
MCLs In the 1988 SDWA amendments.
Congress specified in section 1412(b)(5)
that."Granularactivated--carb'on:is • ••
feasible for the control of synthetic
organic chemicals, and any technology,
treatment technique, or other means
found to be best available for the
control of synthetic organic chemicals
must b'e'at least as effective in
controlling synthetic organic chemicals
as granular activated carbon." On July
25.1990. the Agency proposed the best
available technology (BAT) for the
removal of the 18 synthetic organic
chemicals (SOCs) from drinking water
[55 FR 30420). Today's notice
promulgates the final rule for these
contaminants, including identification of
the Bat. Table 17 provides a summary of
the proposed and final BATs.
TABLE 17.—PROPOSED AND FINAL BAT
FOR ORGANIC CONTAMINANTS
Contaminant
DH2-«thyln«*yf)
atfoatr
Oalaoon _
Dicritorom««n2o-p-diojan —
1.2.4-
TncttorotMonn*.
1. 1.2-
TncttorocttWM.
PropOMd
BAT
GAC/PTA
GAC
PTA
GAC
GAC
GAC
GAC
GAC
GAC
GAC/PTA
GAC
GAC
GAC
GAC
GAC
GAC
GAC/PTA
GAC/PTA
FmalBAT
GAC or PTA
GAC
PTA
GAC
GAC
GAC
GAC
OX
GAC
GAC or PTA
GAC
GAC
GAC
GAC
GAC
GAC
GAC or PTA
GAC or PTA
GAC—Granular Activated Carbon.
PTA—Pack*! Towvr Aaratnn.
OX—OnMkon (Chtonn* or Ozcrw)
With one exception, the BAT
presented in today's notice is the same
as proposed in July 1990. The exception
is glyphosate. The BAT for glyphosate
was proposed as granular activated
carbon (GAC) but has been finalized as
oxidation. This change U discussed
below.
The BAT* for organic* in today's final
rule listed in Table 17 are discussed in
detail in the Technology and Coit (T&CJ
document contained in the rulemaJdng
docket [USEPA, 1992e£ In the T&C
document the available technologies are
discussed, a summary of the literature
documenting treatment performance is
provided, and the cost estimates of BAT
are detailed. The information presented
in the T&C document, including the
availability of.a technology,,!!*'.••••.- ?•'••':
performance, and an estimated cost of
compliance of using the technology are
all considered and form .the basis for
determining the final BATs for the SOCs
in today's rule.
The following discussion addresses
the major concerns expressed during the
public comment period for the July 25.
1990 proposed rule regarding the
proposed BATs for the SOCs.
(1) BAT field evaluations. A number
of commenters expressed concern that
the BAT proposed for the SOCs had not
been demonstrated to be effective
according to the criteria set forth by the
SDWA. They recommended that the
Agency conduct field testing of all the
SOCs under various conditions to
determine the effectiveness of the BATs
as proposed.
The SDWA directs EPA to set the
MCL as close to the MCLG as
"feasible." The SDWA defines
"feasible" as "feasible" with the use of
the best technology. . . which the
Administrator finds, after examination
for efficacy under field conditions and
not solely under laboratory conditions.
[isj available (taking cost* into
consideration)." As mentioned above,
EPA interprets this provision to require
field trials for a technology, not for the
application of that technology to each
individual contaminant. Consequently,
EPA has not required full-scale field
validation of a technology's
effectiveness for treating a specific
contaminant if its effectiveness has been
demonstrated at bench or pilot scale for
that compound. The technology.
however, must reasonably be expected
to perform in a similar manner under
field conditions after considering
aberrations due to scale-up factors.
For three of the contaminant! In the
July 1990 proposal (di(2-
ethylhexyl)adipate and endothall and
2,3,7,8-TCDD), EPA relied on model
prediction* based on the compounds'
physical/chemical characteristics, to
specify GAC ac BAT. At the time of
proposal treatment performance data
were not available due to analytical
difficulties with (di(2-ethylhexyl)adipate
and endothall. Since proposal, however.
the Agency has obtained treatment
performance data for these two
compounds. The treatment performance
studies and data for both (m[2-
ethylhexyljadipate, endothall are
included te the Technology and Co*t
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Federal Register / Vol. 57. No. 138 / Friday, fuly 17. 1992 / Rules and Regulations 31813
Document contained in the rulemaking
docket [USEPA. 1992e). The results of
the studies on these two compounds
support earlier BAT determinations of
GAG made using the model. Further, the
SDWA states that GAG is feasible for
the control of SOCs.
With.respect to.dioxin.,there is a.piloK
scale treatment performance study
indicating removal of diox'n from Agent
Orange using GAG (Chemical Eng..
1977). This study has limited
applicability since the solvent is not
water, but due to the associated health
risks during analysis of dioxin. the
treatment performance of GAG was
determined based solely on the model
predictions.
The Agency is designating GAG as
BAT for dioxin in today's rule in spite of
the lack of performance data. GAG has
been statutorily designated as "feasible
for the control of synthetic organic
chemicals" (section 1412(b)(5). SDWA)
and the results from model predictions
based on the physical/chemical
properties of dioxin support this
determination. In light of the SDWA
statement that GAG is feasible and the
fact that GAG has proven to be effective
in the laboratory and under full-scale
conditions for other synthetic organic
contaminants of similar characteristics.
the Agency believes it is appropriate to
establish GAC as BAT.
Cost considerations. One commenter
stated that a BAT must be evaluated
and applied to site-specific conditions
and that estimated costs might not be
representative of actual operating
conditions.
In response, costs at specific sites
may be higher than estimated in the
Cost and Technology Documents. The
design and costs of the treatment
technologies evaluated as part of the
T&C document pertain to an average
system (not-worst case), and are meant
to be used for a system's preliminary
planning purposes, for generating
national cost estimates and for
determining affordability for typical
systems. Worst-case cost estimates are
not used because the Agency does not
believe that such estimates would
accurately represent the affordability of
treatment for large water suppliers on a
national basis. Individual systems •
should develop a more complete and
detailed design and cost evaluation
based on pilot-plant testing and site-
specific considerations. The cost
estimates presented in the T&C
document provide a basis that can be
used by any system regardless of water
quality.
Use of other technologies. One
commenter noted that treatment
facilities are free to choose technologies
other than BAT to meet the MCL Other
technologies may be chosen in lieu of
BAT because they may be more cost
effective or better suited to the specific
operating condition!! of the particular
site to meet the MCL Making the choice
not to use BAT. however, means that a
system will not be eligible for.a variance
under SDWA section 1415. For example.
if a facility does not install GAC where
it is the designated BAT. but uses PAG
instead, and fails to meet the MCL. the
facility would not be eligible for a
variance. On the other hand, the same
facility may be eligible for an exemption
under SDWA § 141tt if for example GAC
could not be installed due to an inability
to obtain financing and PAG was used
instead, and the facility failed to meet
the MCL
EPA agrees with commenters that
GAC. and any other treatment
technology for that matter, can create
problems if not properly maintained and
operated. Again, technologies other than
GAC. PTA or OX can be used if they
seem better suited to site-specific
conditions in order to achieve the MCL .
Carbon disposal costs. Some
commenters were concerned that the
cost of disposal of spent carbon was not
taken into account at all in the costing
assumptions for the design and
operation and maintenance (O&M) for a
facility. The cost of carbon "disposal" is
essentially the cost of regenerating the
spent carbon (and replacing the 12 to 15
percent lost in the process). For plants
whose daily carbon use is less than
1.000 pounds per day. EPA assumes that
the carbon would be regenerated off-site
by the carbon supplier and that cost is
included in the cost: of.replacement
carbon. For plants whose carbon
demand is more than 1,000 pounds per
day, it is generally economical to
regenerate on-site. The cost of the
incinerator used to regenerate the
carbon and its operation and
maintenance costs are part of the
facility capital and O&M costs already
factored into total costs. The revised
model that EPA now uses in developing
costs [Adams and Clark. 1989] factors
into total costs the expense of carbon
regeneration and replacement.
When powdered activated carbon
(PAG) is used, it is usually disposed of
with the alum sludge in a sanitary
landfill. Because this rule does not
consider PAC to be BAT, EPA is not
addressing the issue of PAC costs,
including the costs of disposal.
PTA and air emissions. One
commenter stated that it is possible to
transfer risk from water to air when
using PTA. As th« commenter points out.
there is a possibility of transferring the
risk associated with VOCs from water
to air when using PTA as a treatment
technology (and that increased costs
may result from a requirement to also
treat the PTA emissions). EPA agrees
that control of such air emissions may
be required by regulations outside the
SDWA (e.g.. local or State regulations)
. and could.increase.the costs, of this •••• .'-•-'
technology. Consequently, the cost of
controlling emissions was estimated as
a separate cost item in Table 13 of the
July 1990 notice and was included in
chapter 7 of the proposed and final T&C
document [USEPA. 1992e|. These
emission control costs can be added to
the PTA costs to get an estimate of the
total costs. The costs are based on
treatment by vapor-phase GAC.
Empty bed contact time. A number of
commenters expressed concern about
the use of an empty bed contact time
(EBCT) of 7.5 minutes and urged field
studies to identify an EBCT or range of
EBCT values. A reference cited in the
July 1990 proposal on general
information about the parameters of the
cost model may have misled these
' commenters. The values used to satisfy
the variables of the parameters were
stated in the T&C document. The EBCT
was used for estimating cost of GAC
removal of SOCs in the July 1990
proposal and in today's rule, and the
EBCT was assumed to be 10 minutes;
not 7.5 minutes. For additional
information on the basis for the use.of a
10-minute contact time. EPA refers
readers to the January 30.1991 rule [56
FR 3555] and-supporting documents.
Carbon usage rate. Some commenters
stated that natural organic matter is a
major contributor to the carbon use rate
(CUR). The concern was that costs of
carbon replacement and regeneration
would be much higher in actual practice
than those calculated in theory. The
Agency agrees with these commenters
that natural organics contributes to the
CUR. To account for the competitive
adsorption and fouling of GAC by these
organics present in the water matrix.
EPA used an adjusted CUR in both the
proposed and final rules. The CURs are
calculated using an equation derived
from the Freundlich isothermal
relationship and a mass balance for
each specific SOC based on distilled
water isotherm data. The CUR is then
adjusted by comparison of field to
distilled water usage rates to account
for the competing effects of natural
organic*. The method used to determine
and adjust the CUR is presented in
Chapter 4 of the Technology & Cost
Document [USEPA, 19S2e] and is a
reasonable approximation of the effects
of natural organic*. The'CUR as well as
the adjusted CUR provide a mechanism
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31814 Federal Regbter / yol. 57. No. 138 / Friday. July 17. 1992 / Rulea and Regulation!
to compare relative absorbabilities, and
ultimately, relative'costs. The Agency
recommends that each system use its
own water quality and geographical
conditions, as well as the appropriate
EBCT and CURs as part of their design
considerations. EPA discussed these
same issues :n its Phase.II final •
regulation (January 30.1991 [56 FR
3556 J).
Powdered activated carbon as BA T.
One commenter suggested that PAC be
considered BAT since it can be used for
removal of pesticide contamination in
surface waters and is the same
substance as GAC. EPA's position is
that the use of PAC may be an
appropriate choice of technology in
certain instances. PAC treatment of
surface water that is only intermittently
contaminated by pesticides or other
SOCs could be both economical, in
combination with an existing filtration
plant, and effective.
While PAC has proven effective in
taste and odor control, its efficacy for
trace SOC removal in drinking water is
variable due to factors such as carbon
particle size, background organics. and
plant efficiency. Therefore. EPA does
not believe that PAC is as effective as
CAC overall, and the Agency has not
designated it as BAT. If application of
PAC will reduce the contaminant below
the MCL in particular cases, it may be
used in lieu of the designated BAT (for
example, if the utility finds that PAC is
more cost effective}. See discussion
above on use of these technologies in
lieu of BAT.
BATforglyphosate. As presented
earlier in today's notice, the BAT
proposed forglyphosate was GAC. One
commenter stated that GAC is not BAT
for glyphosate and indicated that
conventional treatment is more effective
Jn removing this compound from
drinking water. Conventional treatment
typically combines disinfection (usually
chlorine), coagulation, flocculation.
sedimentation, and filtration. EPA
agrees that other technologies appear to
provide better treatment removal
efficiencies for glyphosate than GAC
and conducted additional bench- and
pilot-scale studies to evaluate and
determine the BAT. As the commenter
suggests, and as we determined from
subsequent study. GAC is not effective
in removing glyphosate from drinking
water. Bench-scale treatability studies
documented by Speth (Speth. 1990]
indicate that oxidation using
chlorination (potentially as part of
conventional treatment) or oronation
were significantly more effective
treatment techniques for glyphosate
than is GAC. EPA stated in th«
November 1991 NOA (56 FR 609541 that
it was considering designating these
technologies instead of GAC as BAT for
glyphosate. Today. EPA is identifying
oxidation (using chlorination or
ozonation) instead of GAC as BAT for
glyphosate.
• The proposed BAT was-based OIF
treatment evaluations conducted using
distilled water and a limited number of
data points. Subsequent bench-scale
analyses [Speth. 1990) revealed that
glyphosate's behavior in natural waters
is unlike that of any of the other SOCs
associated with this rulemaking.
Glyphosate exhibits very different
treatability characteristics in distilled
water than in natural waters. This is
thought to be due to extremely slow
kinetics and the influence of organo/
metallic complexation. These additional
studies also provided a preliminary
examination of the effectiveness of
various other treatment methods for
removing glyphosate. The results
indicated that carbon did not remove
glyphosate under raw water conditions.
but oxidation, specifically chlorine or
ozone, was very effective. These bench-
scale studies also seemed to suggest that
under some conditions glyphosate could
be removed by membranes and
coagulation/filtration. These bench
scale studies were completed too late
for inclusion in the July 1990 proposal.
EPA made these bench-scale studies
available for public comment in the
November 1991 NOA.
During 1991, the Agency conducted
pilot-scale studies to further evaluate
the effectiveness of conventional
treatment (including chlorination and
ozonation). The results of the pilot
studies demonstrated that lower levels
of glyphosate were detected after
chlorination or ozonation. The pilot
study also showed, however, that
conventional treatment, which typically
combines disinfection (usually by
chlorine), coagulation/flocculation/
sedimentation and filtration, has not
added effect over chlorination or
ozonation. The results of these pilot-
scale studies were too late to be
included in the November 29,1991 NOA
[56 FR 60954J.
One'commenter raised a number of
concerns in response to the November
1991 NOA regarding the designation of
oxidation as BAT for glyphosate. The
commenter argues that by selecting
chlorination (or oxidation by chlorine)
as BAT the oxidation by-products
themselves may present health risks and
may need to be regulated under the
SDWA in the future. The commenter
goes on the state that the ccwU
associated with the treatment
modifications that would be required to
accommodate an oxidation process
could be appreciable. In addition, public
water suppliers already have to contend
with the Surface Water Treatment Rule
(SWTR). disinfection by-product (DBP)
concerns, and upcoming DBP regulation.
The-commenter also states-'that-the •'•'•'••''•
bench-scale studies included in the
public docket of the NOA [Speth. 1990|
indicated that conventional
coagulation/flocculaticn/sedimentation
was being overlooked by the Agency.
and that additional studies should be
conducted, beyond bench-scale, to
evaluate the effects of pH. coagulant.
water matrix, etc.. on the removal of
glyphosate,by conventional methods.
As mentioned earlier in response to
comments, the Agency conducted
follow-up pilot studies to evaluate the
effectiveness of the various treatment
alternatives identified by Speth [Speth.
1990|. While chlorination used as a
treatment method could raise concerns
of associated health risks due to
disinfection by-products (DBPs). these
concerns can be addressed through
effective precursor removal. This
approach is fully consistent with EPA's
anticipated approach in the upcoming
DBP regulations. To the degree existing
disinfection also accomplishes oxidation
of glyphosate. little or no cost would be
incurred. Installation of new disinfection
has been costed and the cost considered
acceptable..Further, the option to choose
a treatment technology other than the
BAT to meet the MCL when
necessitated by specific conditions is
available (see earlier discussion of
selection of technologies other than
BAT). Also, consistent with the
commenter's recommendation to do
additional pilot-scale studies to evaluate
conventional treatment, including
coagulation/filtration/sedimentation,
EPA has now conducted such studies as
described above, and based on these
studies. EPA has decided not to identify
those technologies as BAT.
The BAT for glyphosate is determined
to be oxidation. Details of the
treatability studies conducted in support
of selecting a BAT for glyphosate can be
found in the Technology 4 Cost
Document [USEPA, 1992e| for the SOCs.
BA Tfor Di(2-ethylhexyl)adipate and
endothall. As stated earlier in today's
notice, proposed BAT for di(2-
ethylhexyljadipate and endothall was
GAC and is not being changed by
today's notice. One cormntinter stated
that EPA should use treatability study
data instead of relying solely on model
predictions to select BAT for di(2-
ethylhexyl)adipate. The proposed BAT
for di(2-
-------
Federal Register / Vol. 57. No. 136 / Friday. July 17. 1992 / Rules and Regulations 318
endothatl was based on model
predictions due to .analytical problems
.encountered during the earlier treatment
evaluations. The Agency recently
conducted additional treatability studies
to provide additional support for the
selection of GAG as. BAT.for these..- •
compounds. •• '
The treatability studies for di(2-
ethylhexyl)adipate and endothail
demonstrate that GAG is as effective in
removing these compounds from
dnnking water as predicted by the
model. In addition, the SDWA section
1412(b)(5) states that GAG is feasible for
the control of SOCs. Therefore, the BAT
for these compounds remains GAG.
Details of the treatability studies
conducted for di(2-ethylhexyl)adipate
and endothall can be found in the
Technology & Cost Document for the
SOCs [USEPA. 1992E].
BATforBenzofa/pyrene. One
commenter suggested that PAC should
be used to remove PAHs. As indicated
in theT&C document, however. PAHs
can be removed more effectively using
GAG than by other technologies:
therefore, the Agency has defined only
GAG as BAT for PAHs. However, any
other technology that seems better
suited to the particular operating
conditions of the particular site can be
chosen as long as the MCL for the
particular SOC is met. See above for a
discussion of the use of other
technologies in lieu of BAT.
6. Determination of MCLs
EPA proposed MCLs for 24 chemicals
based upon an analysis of several
factors, including:
(!) The effectiveness of BAT in
reducing contaminant levels from,
influent concentrations to'the MCLG.
(2) The feasibility (including costs) of
applying BAT. EPA considered the
availability of the technology and the
costs of installation and operation for
large systems.1
(3) The performance of available
analytical methods as reflected in the
PQL for each contaminant. In order to
ensure the precision and accuracy of
analytical measurement of contaminants
at the MCL. the MCL is set at a level no
lower than the PQL
After taking into account the above
factors. EPA then considered the risks at
the MCL level for the EPA Group A and
B carcinogens to determine whether
they would be adequately protective of
public health. EPA considers a target
risk range of 10~4 to 10"* to be safe and
protective of public health when
1 EPA alto evaluates the national cost* and com
lo tnuller lytiemt in its analyti* of economic
Impact!
calculated by the conservative linear
multistage model. The factors EPA used
in its analysis are summarized in Table
18 for the Category11 and Table 19 for
the Category II and III contaminants.
respectively.
a. Inorganic contaminant A/CLtThe''
MCLs for the inorganic contaminants '
promulgated today are at the same level
as the promulgated MCLG for each
contaminant, except for thallium (see
Table 1). Also. EPA is deferring action
on sulfate. and no sulfate MCL is
promulgated today.
The July 1990 notice proposed
alternative PQLs or MCLs for antimony
and thallium. 7\lternative PQLs/MCLs of
0.005 mg/1 and 0,01 mg/1 were proposed
for antimony based on multiples of 5
and 10 times the MTJL As discussed
above, however, the final PQL for
antimony is not being set as a multiple
of the MDL but rather is being set at
0.006 mg/1 based on new PE data
[USEPA,l991d]. This PQL is equal to the
final MCLG for antimony, as discussed
in section III-A. The Agency is.
therefore, finalizing the MCL at the same
level as the promulgated MCLG of 0.008
mg/1 for this contaminant.
The Agency proposed alternative
MCLGs/MCLs for sulfate of 400 mg/1
and 500 mg/1. Today EPA is deferring
promulgation of a sulfate MCL because
the Agency believes it needs to consider
innovative approaches to regulating
sulfate. The length of this deferral period
will be determined in the course of
ongoing litigation with an interested
citizen's group concerning EPA's legal
deadlines for establishing regulations
for drinking water contaminants. Unlike
most drinking water pollutants, sulfate
appears to be primarily of concern for
Unacclimated transient populations (as
well as for infants).
Because of the high cost of regulating
sulfate. its relatively low risk, and its
impact primarily on the transient
consumer. EPA is deferring the
promulgation of the sulfate MCLG and
MCL In the interim. EPA intends to
resolve the following issues: (1) Whether
further research is needed on how long
it takes infants to acclimate to high
sulfate-containing water. (2) whether
new regulatory approaches need to be
established for regulating a contaminant
whose health effect is confined largely
to transient populations, and (3) whether
the Agency should revise its definition
of Best Available Technology for small
systems (i.e., what should be considered
affordable for transient noncommunity
water system*).
. During this deferral period, the
Agency also intends to consider ways to
expedite the proceas for granting
potential exemptions and variances to
ease the impact of eventual regulations
on small systems. Also in the interim.
the Agency plans to issue a Health
Advisory and encourage States whets
sulfate levels may be high to conduct
additional monitoring and encouragetfh
" use of alternative-water supplies where
appropriate.
For thallium, alternative PQLs/MCLs
of 0.002 mg/1 and 0.001 mg/1 were
proposed in the July 1990 notice based
on 5 and 10 times the MDL As
discussed above, however, the final RQI
and MCL for thallium is being set today
at 0.002 mg/1 based on new PE data
.[USEPA. 1991d]. The. MCL for thallium-ii
limited by the sensitivity of available :
analytical methods (i.e.. it is being set^at
the PQL). The PQL constraint results in
an MCL higher-than the 6.0005 mg/1
MCLG by a factor of 4. However, the
Agency has concluded that the
promulgated MCL is adequately
protective of health because the MCLG
includes a large cumulative safety factor
of 3.000. Thus. EPA believes that "the
health risks of exceeding the MCLG up
to the MCLare minimal.
EPA has determined that each
inorganic contaminant has one or more
BATs to reduce contaminant levels to
the MCLG. and that the BAT(s) is
feasible (as defined by the Act).
analytical methodologies are available
to ensure accurate and precise
measurement for each MCL and each
MCL adequately protects public health.
EPA also calculated the household cost
for water suppliers to remove IOC
contaminants to or below the MCLs.
based on the identified BATs. The
inorganic contaminants are not expected
to occur in the very large water systems
and household costs were not estimated
for them. In the largest systems where
they may occur (25.000-50,000
population), costs were approximately
$100/household per year, and would
likely be lower for larger systems. EPA
believes these costs are reasonable.
Also, the national costs associated with
the MCLs for these contaminants, as
shown in the RIA. are considered
reasonable. Also, the national costs
associated with the MCLs for these
contaminants, as shown in the RIA. are
considered reasonable.
B. Synthetic organic contaminant
MCLa—(1) Category I contaminants.
EPA considered the same factors in.
determining the proposed MCLs for
Category I contaminants as for Category
II and III contaminants. However, the
proposed MCLGs for Category I
contaminant* are zero, a level that by
definition is not "feasible" because no -
analytical method is capable of
determining whether a contaminant
-------
31816
Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
level is zero. The lowest level that can
be reliably measured is the'PQL. EPA
calculated PQLs for these contaminants
from available analytical performance
data, as described above.
In developing MCLs. the Agency
attempts to attain a level as close to the
MCLG as is feastble..For carcinogens." •
EPA evaluates the cancer risk at various
contaminant levels in order to ensure
that the MCL adequately protects public
health. The Agency targets a reference
cancer risk range of 10"' to 10"* excess
individual risk from lifetime exposure
using conservative models which are not
likely to underestimate the risk. Since
the underlying goal of the Safe Drinking
Water Act is to protect the public from
adverse health effects due to drinking
water contaminants. EPA seeks to
ensure that the health risks associated
with carcinogenic contaminants are not
significant.
For most contaminants regulated
today. The PQL is identical to that
proposed in the July 1990 notice. In the
case of dioxin. EPA lowered the PQL
based upon a new MDL study using
Method 1613 (USEPA. 1990hJ. This study
Identifies an MDL of SxiO"'mg/l.
which is exactly twice as low as the
MDL of ixWrng/l that EPA identified
in the July 1990 proposal. EPA provided
this new information through the
November 29.1991 Notice of
Availability. Based on the new
information. EPA has decided to set the
PQL at five times the MDL or at 3x10"'
mg/1.
In the July 25.1990 proposed
regulation for dioxin [55 FR 30416). EPA
proposed to set the PQL (and MCL) at
five times the MDL. rather than ten
times the MDL because of concerns
about.the health risk-posed aUhe •••• ••"
concentration corresponding to ten
times the MDL. EPA recognized that
some loss of analytic precision would
likely result from th'is, but believed it
was warranted by the additional health
protection that would be ensured by the
lower MCL In soliciting public comment
on the new dioxin analytic method
(1613) and MDL EPA asked for
comment on this same issue, of whether
the additional health protection afforded
by a lower MCL warranted the likely
reduction in analytic precision. Several
commenters expressed concern about
likely reduction in analytic precision. In
using a multiplier of five rather than ten
in setting the PQL (based on the new
data), estimated lifetime cancer risks
would be reduced from 2.5X10"*. to
1.3x10"*. EPA believes this reduction in
risk is warranted, because it brings the
MCL closer to the 1 xlO~* target
maximum risk that EPA uses for
national primary drinking water
regulations. Also, as discussed above.
EPA believes that the degradation in
analytic precisional accuracy is not
unreasonable in going from 50 to 30 ppq.
EPA also calculated the annual
household costs for large systems to
remove the SOC contaminants to or
below the MCL using GAC. PTA or
oxidation. As Table 18 shows, these
costs are estimate to be generally about
$20 per household per year for large
systems to jnstall and operate any of
these technologies. Cost estimate* have
not changed frdm the estimates in the'
proposal. No significant comments on
unit treatment costs were submitted.
EPA believes these costs are
reasonable, as are the associated
national costs as shown in the RIA. EPA
therefore promulgates the MCLs at the
levels listed in Table 18.
Pursuant to SDWA section
1412(b)(10). the effective date for all
MCLs promulgated today (except for the
MCL for endrin) is 18 months after
publication of today's notice (see the
beginning of today's notice for the exact
date). The effective date for the MCL for
endrin is set at 30 days after publication
of today's notice. The MCL for endrin
promulgated today represents a
relaxation of the existing MCL for
endrin (from 0.0002 mg/1 to 0.002 mg/1).
Even though SDWA section 1412(b)(10)
calls for the effective date of MCLs to bt
18 months after promulgation. EPA
interprets this provision not to apply in
the case of an existing MCL that is being
revised to a higher level, since utilities
do not need time to prepare to meet the
revised level (they are, in-effect. already
required to be meeting it).
TABLE 18—MCL ANALYSIS FOR CATEGORY I SYNTHETIC ORGANIC CONTAMINANTS
SOC contaminant
Ocnitxomctr.jrw „,,„ _..„.,
OitZ-ethytfiexytlpnthatate....
HcxacftlcfobenzenG ,«....:.,„ „
Benzofajpyrene .«..«....».».«..^ „
2,3.7,8-TCOD™
Final
MCLG '
(mg/l)
0
0
0
o
0
Final
MCL
(mg/l)
0.005
0.006
0,001
00002
3x10"»
10'«
risk -
(mg/l)
0,05
0.4
0.002
00002
2x 10"'
PQL
(mg/l)
0.005
0.006
0.001
00002
3x10'§
Annual h
cos
GAC
S20.00
20.00
2000
2000
ousanott
ts»
PTA
18.00
Notes
MCL it *t 1.3x 10M risK.
1 EPA polcy is mat lot all Category I carcinogens me MCLG "» zoro.
1 For large systems.
(2) Category II and III contaminants.
For the Category II and III SOC
contaminants listed in Table 19, each of
the MCLs was proposed equal to its
proposed MCLG. Because the MCLGt
for di(2-ethylhexyl)adi-pate and
simazine have changed from the levels
proposed in July 1990, as discussed
above, the MCLs have also changed.
The MCL for-di(2-ethylhexyl)adipate
changed from 0.5 to 0.4 mg/l and the
MCL for simazine changed from 0.001 to
0.004 mg/L The MCL for 1.2.4-
trichlorobenzene changed from 0.009 to
0.07 mg/l. Both of these changed MCLs
are equal to the final MCLGs. which
were revised based on a reassessment
of the health data as discussed above.
Section 1412 of the S,DWA requires
EPA to set MCLs as close to the MCLGs
as is feasible (taking costs into
consideration). EPA believes that it is
feasible to set the MCL* at the MCLGs
for the Category II and Category III
contaminants because (1) the PQL for
each contaminant is at or below the
level established by the MCLG: (2) BAT
can remove each contaminant to a level
equal to or below the MCLG: and (3) the
annual household cost to install BAT in
large systems is reasonable. Final
estimated costs are the same as were
established for the proposal. EPA
believes that these costs are affordable
for large systems. EPA also believes the
associated national costs, as shown in
the RIA, are reasonable. Therefore. EPA
promulgates the MCL* for the non-
carcinogenic contaminants equal 10 their
MCLG*.
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I
Federal Raster / Vol. 87. No. 138 / Friday. July 17. 1992 / Rules and Regulations
31B1
TABLE 19.—MCL ANALYSIS FOR CATEGORY II AND III SYNTHETIC ORGANIC CONTAMINANTS
5OC contaminant
Dal&pon ..«.
Ort2-ftttryHHcy)aflip3H' ... - — . .. . .
QtnoSffO • ••
DtQudt , :.
£ndothafl -
Enflfin
Glypfiosate ..— .
HexacMofocydopefitadiene
Oxamyf (Vydate)..., ,
Pictofafn ,„
Simazine
1 2 4-TrtcniOfOt>Gn20O6 — •
1 1 2-Tncntofoeihana
! Final
;. MCLG
| (fftg/l)
I 02
-- , , ,,,( 0*
. ; 0007
: 002
1 01
1 0002
: o 7
i 005
0 2
• 05
i 0004
j 0 07
. . .. • 0003
I
Final '
MCL
(mg/l) j
02 I
04 I
0.007
0.02 :
01
0002 '
0.7 '
005 j
02
OS :
0.004 !
0.07 |
0005 (
POL
(rrg/l)
001
0.005-
0002
0.004
009
0001
0.4
0001
005
0.002
0001
0005
0.005
Annual household costs
BAT '
GAC i PTA !
$3500
25.00
20.00
25.00
' 3500
2000
20.00
25.00
35.00
2000
20.00
25.00
|
S1700|
'" 1
1
£1 Sfl
1.7 00 :
1700 !
42.00 ;
uung
OX
V
-900
1 For iarg« systems.
C. Compliance Monitoring
Requirements
1. Introduction
The proposed compliance monitoring
requirements (55 FR 30427} included
specific monitoring requirements for
inorganic contaminants (IOC*), volatile
organic contaminants (VOCs); and non-
volatile synthetic organic chemical*
(SOCa). EPA proposed that all
community and non-transient non-
community water systems comply with
the monitoring requirements for all
contaminants. EPA also requested
comment on whether the MCL for
sulfate and the associated monitoring
requirements should apply to transient.
non-community system since this
contaminant is associated with acute
effects. The compliance monitoring
requirements promulgated in today's
rule apply to all community and non-
transient non-community water systems.
The compliance monitoring
requirements that EPA is promulgating
today are the minimum currently
necessary to determine whether a public
water supply delivers drinking water
that meets the MCL*.
The proposed compliance monitoring
requirements for the contaminants in the
July 25.1990 notice were similar to the
monitoring requirement* proposed in a
May 1989 notice [54 FR 22124] for 38
inorganic and synthetic organic
contaminants. In the July 1990 proposal
{55 FR 30428), EPA explained that the
Agency's goal in promulgated
compliance monitoring requirement* is
to standardize the requirement* and to
synchronize the schedules to minimize
overall sample collection.and analysis .
efforts. In keeping to that goal, the
Agency further stated in that notice [55
FR 30429] that change* to the monitoring
requirement* in the final rule to the May
1989 proposal would likely effect the
final requirements for the contaminants
in today's notice.
EPA promulgated final regulations for
the contaminants in the May, 1989
proposed rule on January 30,1991 and
July 1.1991 [56 FR 3528 and 56 FR 30266,
respectively]. In the January 1991 final
rule. EPA described a standard
monitoring framework that was
developed by the Agency based on the
proposed monitoring requirements and
on the comments received by EPA in
response to the May 1989 notice. The
final rule, and the November 1991. NOA
concerning today's rule, indicated that
EPA intends to apply this framework to
future requirements for source-related
contamination (i.e., inorganics, VOCs,
SOCs and radionuclides), as
appropriate. The framework and how it
applies to today's rule is described in
more detail below.
The contaminants in today's rule
usually occur at limited frequencies.
thereby justifying flexible monitoring
requirements. In general, the possible
occurrence of these contaminants in
drinking water may be predictable to
some extent based upon a multiplicity of
factors such as geological condition*,
use patterns (e.g., pesticides), presence
of industrial activity in the area, type of
source or historic record. Therefore. EPA
believes that State* should be allowed
the discretion to increase or decrease
monitoring based on established criteria
and site-specific conditions. A* part of .
today's rule EPA is withdrawing these
contaminants from the unregulated
contaminant monitoring requirement* of
§ 141.40 since they will now be
monitored as regulated contaminant*
under J i 141.23 and 141.24.
In developing th« compliance
monitoring requirement* for these
contaminant*. EPA, considered:
(1) Tb« likely lource of drinking water
contaminant*.
.(2) The nature of the potential adverse
health effects, i.e.. chronic versus acute
effects.
(3) Differences between ground and
surface water systems.
(4) How to collect samples that are
representative of consumer exposure,
(5) Sample collection and analysis
. costs,
(6) The use of historical monitoring
data to identify vulnerable systems.
(7) The limited occurrence of some
contaminants, and
(8) The need for States to tailor
monitoring requirements to system- and
area-specific conditions.
EPA monitoring requirements are
designed to ens>'re that compliance with
the MCLs is met and to efficiently utilize
State and utility resources. EPA's goal in
today's rule is to ensure these
monitoring requirements are consistent
with monitoring requirements
promulgated previously by EPA and
with known occurrence trends. The
monitoring requirements promulgated
today focus monitoring in individual
public water systems on the
contaminants that are likely to occur, an
approach that includes:
• Allowing States to reduce
monitoring frequencies based upon
system vulnerability assessments for the
organic chemicals listed in S 141.61 (a)
and (c),
• Allowing States to target monitoring
to those system* that are vulnerable to a
particular .contaminant.
• Allowing the use of recent
monitoring data in lieu of new data if
the system has conducted a monitoring
program generally consistent with
today's requirement* and using reliable
analytical method*.
• Encouraging the States to use
historical monitoring data meeting
specific quality requirement* and other
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31818
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Federal Regular / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
available records to make decisions
regarding a system's vulnerability.
• Requiring all systems to conduct
repeat monitoring unless they
demonstrate through an assessment or
other data that they are not vulnerable.
• Designating sampling locations and
frequencies,that permit simultaneous..
monitoring for all regulated source-
related contaminants, whenever
possible.
• Phase-in monitoring requirements
based on system size. For systems with
150 or more service connections.
mcn:lor:ng begins in the first compliance
period (January 1.1993 to December 31.
1995). For those systems wi.th less than
150 service connections, monitoring
begins in the second compliance period,
(January 1.1996 to December 31.1998).
Although base monitoring
requirements for surface and
groundwater systems are the same for
all contaminants, groundwater systems
will qualify more frequently for reduced
monitoring and return more quickly to
the base monitoring requirements
because (1) the sources and mechanisms
of contamination for ground and surface
water systems are different. (2) the
overall quality of surface waters tends
to change more rapidly with time than
does the quality of ground waters, and
(3) seasonal variations tend to affect
surface waters more than ground
waters. Spatial variations are more
important in ground waters than in
surface waters since groundwater
contamination can be a localized
problem confined to one or several wells
within a system. Therefore, monitoring
frequency is an important factor to
determine baseline conditions for
surface water systems, while sampling
location within the system generally is
more important for groundwater
systems. Today's monitoring
requirements generally require surface
water systems to monitor at an
increased frequency for longer periods
than groundwater systems.
2. Effective Date
In the July 25.1990 Federal Register
Notice. EPA proposed to allow an
additional 12 months after the effective
date of the rule taking final action on the
proposal for public water systems to
complete the first round of sampling and
analysis and to report the results of such
monitoring to the States. The effective
date of the rules is by statute, 18 months
from promulgation. EPA also proposed
to allow an additional 12 months after
the effective date of the final regulations
for the States to complete vulnerability
assessments.
Most commenter* supported
extending the initial monitoring and
reporting period as well as the date to
complete vulnerability assessments.
They claimed that the 18 months
compliance schedule is too rigorous.
especially since extensive investigation
is required. Some commenters claimed
there is a lack of laboratory capacity for
conducting analyses using- the new - . •
analytical methods and a lack of
qualified staff as a rationale for
extending the first.round of monitoring
and the reporting of the results of such
monitoring to the States. Other
commenters cited the impact on State
resources to properly notify water
systems regarding the new monitoring
requirements, develop .the necessary
guidance and procedures, train staff, to
review vulernability assessments.
reduced monitoring decisions, etc.. and
to be prepared to administratively
handle the data generated, as the
rationale for allowing States sufficient
time to initiate the monitoring
requirements. One commenter suggested
that small systems be given more time to
comply with the requirements because
of the cost burden on these systems.
Another commenter suggested that the
systems should be allowed to submit to
the State their own schedule for
compliance for State approval.
In the November 29.1991 NOA. EPA
.stated that it was considering requiring
that monitoring begin during the first
compliance period following
promulgation. This change would
synchronize the monitoring schedule for
the 23 contaminants with those
promulgated for other SOCs and lOCs in
the January 30.1991 notice. Two
commenters supported this change. ,
However. 14 commenters disagreed with
the change since they felt it effectively
moved monitoring up three years from
what was proposed, there would be a
lack of time to conduct vulnerability
assessments, inadequate time for
laboratories to become certified, and
increased cost to States and public
water systems.
EPA agrees with the commenters that
problems may occur in the early stages
of implementing the monitoring
requirements. These problems are
alleviated to some extent, however, by
the fact that this rulemaking is adopting
the Agency's Standard Monitoring
Framework (which EPA originally
adopted in the January,30.1991 rule
setting regulations for 33 contaminants).
_and is adopting a phased approach for
initial monitoring. Specifically, the
Agency has decided to require that
monitoring for the contaminants in
today's rule b« completed (1) during the
first compliance period, as specified in
the-Standard Monitoring Framework.
which begins January 1.1993 and end*
December 31.1995 for systems with 150
or more service connections, and (2)
during the period beginning January 1.
1996 and ending December 31.1998 for
systems with fewer than 150
connections. In addition, all
vulnerability assessment decisions must
be completed prior to' the calendar year
when the initial monitoring must be
completed. Laboratories can be granted
provisional certification to perform
analyses for the contaminants in today's
. rule during the 1993-1995 compliance
period. See the discussion under
Laboratory Certification. •
EPA believes this phased-ih time
frame allows adequate time for
implementation of the monitoring
requirements since for larger systems it .
provides for more than two additional
years after the effective date of today's
rule for completion of the first round of
sampling and analysis and for small
systems it provides three years
additional time. This monitoring
schedule also coincides with the
sampling and analysis schedule for 38.
contaminants previously regulated (56
FR 3526 and 56 FR 30266|. By allowing
systems with less than 150 service
connections to begin initial monitoring
in the second compliance period
(January 1.1996 to December 31.1998).
more time is allowed for States.
laboratories, and small systems to be
fully prepared (i.e.. conduct vulnerability
assessments, find funding).
EPA believes that the earlier 1993-
1995 compliance period for those
systems with 150 ormore service
connections is appropriate, to better
protect health. These systems would
have been required to begin monitoring
for these contaminants under
unregulated monitoring requirements of
the January 30.1991 rule. Since many of
the previously unregulated
contaminants are contaminants being
regulated in today's rule, the Agency
believes the 1993 monitoring will result
in only minor increased monitoring
impact. Those individual contaminants
moving from "unregulated" to
"regulated" status are being deleted
from the unregulated contaminant
monitoring requirement*.
States have the discretion, and may
well choose, to require a percentage
(e.g., one-third) of the required systems
to monitor during each year of the three-
year compliance period States have the
option to prioritize monitoring based on
system size. EPA ha* decided not to
allow systems to submit their own
monitoring schedule for State approval
as some commenters suggested. EPA
believes States need to control the flow
of samples and data to them in order to
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rnoay. puy
ana- «ggmanon«
orderly implementation and
enforcement, within the regulatory
requirements and avoid undue
administrative burdens and potentially
unmanageable enforcement problems.
3. Standard Monitoring Framework
In response to the May 1989 notice
covering a different set of contaminants.
EPA received extensive comment*-;
stating that the proposed monitoring
requirements were complex and would
lead to confusion and misunderstanding
among the public, water utilities, and
State personnel. Commenters also cited
the lack of coordination among various
regulations. Many commenters
suggested that EPA simplify, coordinate.
and synchronize the proposed regulation
with previous regulations. In response to
these comments. EPA developed a
Standard Monitoring Framework to
reduce the complexity of the monitoring
requirements, coordinate the
requirements among various regulations.
and synchronize the monitoring
schedules. This framework is discussed
extensively in the January 30.1991 final
rulemaking to the May 1989 Notice [56
FR 3560]. The Agency also indicated
that this framework will serve as a guide
for future source-related monitoring
requirements. The framework was
developed based on the proposed
requirements, the options and requests
for comments EPA discussed in the
proposal, and the comments received by
EPA.
The use of a Standard Monitoring
Framework for the contaminants in
today's rule was supported by many of
the comments received. Commenters
cited the efficient use of resources as the
major reason to synchronize the
monitoring requirements.
EPA believes that using a Standard
Monitoring Framework satisfies the
comments that recommended reducing
the complexity of the requirements,
synchronizing monitoring schedules.
standardizing regulatory requirements.
and giving regulatory flexibility to
States and systems to manage
monitoring programs. EPA believes
these changes will reduce costs by
combining monitoring requirements tor
the contaminants regulated by the
January 30.1991 rule and today's rule
(i.e.. the presence of multiple
contaminants can be evaluated in a
single laboratory sample and analysis.
or by a single vulnerability assessment)
and will promote greater voluntary
compliance by simplified and
' standardized monitoring requirement*.
v. Use of the framework envisions a •
cooperative effort between EPA and
States. The monitoring requirement*
promulgated today are the minimum - •
fede<*al requirements necessaiy to
ascertain systems' compliance with the
MCLs. In some canes. States will
increase the monitoring frequencies
beyond the federal minimums to address
site-specific conditions.
For all contaminants contained in
today's rule, minimum (or base)
monitoring requirements requirements
may be1 increased or decreased by
States- based upon prior analytical
results and/or the results of a
vulnerability assessment. The
monitoring requirements outlined today
follow to a large extent the requirements
proposed on July 25.1990. In the July
1990 proposal EPA stated as a goal to
efficiently utilize State and utility
resources and be consistent with
monitoring requirements previously
promulgated by EPA. EPA believes that
today's requirements meet that goal.
a. Three-, six-, nine-year cycles. In
order to standardize the monitoring
schedule for different regulations. EPA
has established nine-year compliance
cycles. Each nine-year compliance cycle
consists of 3 three-year compliance
periods. All compliance cycles and
periods run on a calendar year basis
(i.e.. January 1 to December 31). The
January 30.1991 rule established the
first nine-year compliance cycle
beginning January 1.1993 and ending
December 31.2001: the second cycle
beginning January 1.2002 and ending
December 31.201ft etc. Within the first
nine-year compliance cycle (1993 to
2001), the first compliance period begins
January 1,1993 and ends December 31.
1995; the second begins January 1.1998
and ends December 31.1998; and the
third begins January 1.1999 and ends
December 31. 2001..
In the January 1991 Notice. EPA
required that initial monitoring (which
was defined as the first full three-year
compliance period beginning 18 months
after the promulgation date of a rule)
must begin in the First full compliance
period after the effective date of the
final rule. EPA solicited comments on
this issue in the November 29.1991 NOA
and is modifying initial monitoring, as
described above. For today's regulation.
the effective date is January 17.1994.
The next full three-year compliance
period after this effective date begins
January 1.1996. After reviewing
comments received, the Agency has
decided that systems serving 150 or
more service connections must conduct
initial monitoring during the January 1,
1993 to December 31.1996 period and
those serving less than 150 service
connections must conduct initial •
monitoring'during the January 1.1998 to
December 31.199(5 period. EPA believes
the phase-in of monitoring based on
system size will increase public health
protection to the public by identifying
noncompliance earlier for larger systen
which serve a large fraction of the
population (and which would have bee;
required to monitor these contaminants
in any event under the "unregulated
contaminant" requirements of the
January 1991 rule). At the same.time..th
phase-in will allow States, small
systems, and laboratories more time to
effectively implement today's rule for
small systems. EPA believes this is an
appropriate balancing of the need to
identify noncomplying systems through
monitoring, and the implementation
burden on States and laboratories. This
change would synchronize the
monitoring schedule for the 23
contaminants in this rule with those
promulgated for other SOCs and lOCsit
the January 30.1991 notice.
Under the July 1990 proposal,
monitoring for the contaminants in this
rulemaking would have been required to
be initiated no later than November 199C-
(i.e.. the effective date of this
rulemaking). EPA does not believe that
changing the initial monitoring schedule
to begin January 1993 instead of
November 1993 for systems with .150 or
more service connections will
significantly affect costs for those
systems. Under this schedule. States
must establish an enforceable
monitoring schedule for each system
during the initial three-year compliance
period. States have the discretion to
schedule systems by size, vulnerability.
geographic location, laboratory access.
or by other factors. In some cases
• systems will not need to conduct
monitoring until the latter part of the
first three-year period, rather than
needing to start monitoring immediately
as of January 1993 (see discussion of the
Standard Monitoring Framework at 56
FR 3560). In addition. EPA believes there
will be a decrease in costs due to the
effects of synchronizing, the monitoring
requirements in this rule with those of
earlier rules—e.g.. there will be a cost
savings resulting from a system's ability
to evaluate the presence of multiple
contaminants with the analysis of a
single sample, and to perform
vulnerability assessments covering
multiple contaminants.
Several commenters believed that
States would be unable to develop
adequate certified laboratory capacity
in order to monitor during the 1993-199S
period. EPA has responded to this
concern by encouraging provisional
certification of laboratories. «*
discussed above.
b. Base monitoring requirements. In
order to standardize lh« monitoring
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31*2*
, grMal3«V
VSOL
sad
reqtdreaenti. EPA ka« established base
(or minimum) monitoring frequencies for
all systems at each sampling point
These bate monitoring frequencies
apply to all community and noa-
transient water systems, la cases of
detection or non-compliance. EPA has
specified increased monitoring
frequencies from the base, The*e ,.
increases are explained below. Systems
will also be able to decrease monitoring
frequencies from the base requirements
by obtaining waivers from the State
where a State permits such waivers.
Decreases from base monitoring
requirements through waivers are
discussed in general under the section
on decreased monitoring and in the
discussion of monitoring frequency for
each class of contaminants.
In most cases, these Increased or
decreased frequencies are similar to the
frequencies proposed in July 1990.
Specific changes are discussed below
under each contaminant group.
Inorganic contaminant base
requirements are the same as
proposed—one sample at each sampling
point every three years for groundwater
systems and annually for surface water
systems. Modification of base
requirements for VOCs is discussed
below in the section on VOC monitoring
frequency.
For the non-volatile synthetic organic
compounds (SOCs). EPA proposed that
monitoring was not required unless the
State determined that the system was
vulnerable based upon a State-
conducted assessment. EPA requested
comment on the appropriate time frame
for completing these assessments. If die
State determined that a system was
vnlerable to these SOCs, systems would
be required to monitor on a three- or
five-year schedule depending upon
system size and whether contaminants
were detected.
The July 1990 notice also mduded an
alternative monitoring scheme which
would require all CWSs and non-
transient, non-community water systems
(NCWSs) to monitor for the non-volatile
SOCs at specified (base) frequencies.
Most comments EPA received opposed a
round of initial mora'toring-by all
systems. These commenteis cited the
lack of occurrence of these
contaminants in drinking water and the
expense of monitoring. Several
commeaters questioned the availability
of sufficient laboratory capacity.
After reviewing and evaluating the
comments on saonitorfcig for the SOCs ia
the May 1998 Notice, EPA adopted en
alternative saooitorfag approach which
requires systems to monitor it specified
base frequencies imless the
requiremesrts are warred (eftber redaced
or eliminated) by tne State. The rei
for this change are given in the January
1991 rule (56 FR 3S60J. In summary, the
requirement that all systems .monitor for
these contaminants is more protective of
health than were the proposed
requirements because systems will be
required to monitor if the State does not
conduct a.vulnerability assessment, or,.
does not approve a vulnerability
assessment conducted by the system.
The result of this change is that mere
will always be an enforceable
requirement in the absence of a State
waiver.
In today's rule EPA is adopting the
same monitoring approach for the SOCs.
EPA believes that the cost impact of this
approach is the same as under the
proposed scheme provided a
.vulnerability assessment is conducted
and a waiver is granted.
EPA has combined the above '
with the provision that public water
systems may conduct meir own
vulnerability assessments and, at me
State's discretion, may obtain s waiver
if they are determined not to be
vulnerable (see waiver discussion
below}. EPA has shifted the
responsibility to conduct vulnerability
assessments from States to systems
because tne vulnerability assessment is
a monitoring activity that historically
has been a system responsibility. Each
individual system can decide whether to
conduct a vulnerability assessment
(rather than simpty going right to
monitoring) based on cost, previous
monitoring history, and coordinatian
with other vulnerability type
assessments (Le_ sanitary surveys.
Wellhead Protection Assessments}. In
addition, because of States' Indicated
resource shortfalls, many States might
not ccndact vulnerability assessments.
Thougn EPA is permitting systems to
conduct vulnerability ai•«?laments.
approval of waivers based on those
vulnerability assessments rests with tto
States. EPA believes the changes
outlined above address, in part, the
State resource issue and will result in
adequate monitoring and enforceable
drinking water standards.
Based on limited occurrenca data.
EPA anticipates that most system*
would qualify for a waiver from
monitoring tor most SOCs in today's
rule, m cases where a system is not
granted a waiver by the State, it wul be
reqvtred to monitor at the specified base
frequency. In SOB. for the reasons
specified above, all system wiH tw
required to monitor for all SOCs with an
opportunity for reduced monitoring
based wpoci a vulnerability i
monitoring re
i for all VOCs,
EPA promulgated on fuly 1. 199t
modifications to the monitoring
requirements for me 18 VOCs in two
previous rules (}uiy fi, 1987 and January
30. 1991 Federal Register Notices), The
comments submitted to EPA during the
comment period for the January 1991
notice reveated-support for •.-'•• ...
synchronization of the monitoring
requirements and schedules. Therefore.
the monitoring requirements in today's
rule are identical to the requirements for
these previously regulated VOCs [56 FR
39267J.
d. Increased monitoring. In general.
today's rule requires monitoring
frequencies to increase when a
contaminant is measured at a certain
concentration. These concentrations are
specified in each rule, and vary by class
or toxicity of the contaminant. la today's
rule, consistent with the monitoring
requirements set forth in the January
1991 rule for other inorganic
contaminants. VOCs. and SOCs. these
"trigger" concentrations are set at (1)
the MCL* for the inorganic
contaminants: and (2) the analytical
detection limits for VOCs and SOCs.
The detection limit for each VOC is
0.0005 mg/1. The SOC detection limits
are the method detection limits given in
Table 14 and { 14L24(i)(ia). The
rationale for varying the detection limits
monitoring is addressed in
l«pona
c. Votctilt Organic Chemical*
(VOCtf. fa orde? to standardize tfe '
each section for the contaminant
monitoring frequencies below (also see
the January 1391 rule, 56 FR 3560-66).
After exceeding toe trigger
concentration for each contaminant.
systems raust immediately increase
monitoring to quarterly (beginning in the
subsequent quarter after detection) to
establish a baseline of analytical results.
Groundwater systems are required to
take a mmtmnra of two samples and
surface water systems must take four
samples before the State may permit
less frequent monitoring. EPA a
requiring surface water systems to take
a minimum of four tanp^es (rather than
the two samples required for
groundwater systems) because .surf ace
water is generally more variable man
ground waiter and. consequently.
additional sampUmj is required to
determine that th« system « "reliably
and consistently" below the MCL.
Today's rale allows a State, after a
baseline is established, to reduce the
quarterly mooitoring frequency if the
system is "rettabiy and consistently"
betow dae MCL. "Reliably and
consistently" sneans that the State has
enough ccofideoce list fctare sampling
result* w(E b« svfocieatrjr below the
MCL to justify reducing the quarterly
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Federal Register / Vol. 57. No. 138 / Friday, July 17. 1992 / Rules and Regulations
322
monitoring frequency. At a minimum, all
individual samples should be below the
MCL. Systems with widely varying
analytical results or analytical results
that are just below the MCL would not
meet this criterion. In all cases, the
system remains on a quarterly sampling
frequency until the State determines that
the system is."reliably.and consistently"-
below the MCL. EPA is adopting this
approach based on comments received
on the May 1989 and July 1990 proposed
rules that suggested the EPA allow
States to modify the monitoring
schedules in those systems which are
less than the MCL. EPA believes this
approach will result in consistency
among the regulatory requirements for
the different classes of contaminants.
. In the July 1990 proposal. EPA
requested comment on whether EPA
should reduce the three year quarterly
monitoring requirement to one year of
quarterly monitoring in situations where
initial monitoring shows particularly low
levels of detection relative to the levels
of concern (i.e., MCLs) or in situations
where cleanup activities have resulted
in low levels of detection. Several
commenters indicated that a minimum
of 12 quarters after monitoring had been
increased by a trigger level was too long
and supported a reduction in the
monitoring requirements in cases such
as these. These commenters suggested
that EPA should require sufficient
monitoring to establish a baseline. In the
January 1991 Notice EPA prescribed a
minimum of two samples for
groundwater systems and four samples
for surface water systems to establish a
baseline. EPA is adopting the same
approach today because the Agency
agrees with commenters who pointed
out that systems whose analytical
results remain below the MCL do not
pose a health threat.
In the July 1990 proposal, the Agency
proposed to reduce the repeat
monitoring requirements when a
contaminant is consistently-detected at
less than 50 percent of the MCL Many
commenters objected to this trigger,
stating that it was "arbitrary". The
Agency modified this requirement in the
January 1991 notice with respect to other
contaminants to give States additional
flexibility to reduce monitoring for those
systems whose analytical results are
"reliably and consistently less than the
MCL" (see 5 § 141.23(c)(8).
141.24(f)(ll)(ii) and 141.24(h)(7)(ii) 50 FR
3560-68. 3580, 3584. 3588). EPA has
decided that systems meeting this
criteria are also eligible for reductions
from the increased monitoring frequency
requirements for the contaminants in
today's rule.
e. Decreased monitoring. Systems
may decrease monitoring from the base
requirement by receiving a waiver from
the State. State waivers may either
eliminate the monitoring requirement for
that compliance period (for SOCs) or
reduce the frequency (for inorganics and
VOCs). Waivers are either based on a
review-of established criteria ("a waiver
by rule") or by a vulnerability
assessment.
A "waiver by rule" is based simply on
meeting certain criteria set out in EPA
regulations and based, for example, on
previously collected analytical results.
For example. 5 141.23(c) (originally
adopted in the January 1991 notice and.
by this notice, applicable to the
contaminants in today's rule) specifies
that States may grant "waivers by rule"
to systems for five inorganic
contaminants. The waivers are effective
for up to nine years (or one compliance
cycle). In order to qualify for a waiver, a
system must have a minimum of three
previous samples (including one taken
after January 1.1990) with all analytical
results below the MCL The State must
consider a variety of issues in making a
"waiver by rule" determination, such as:
(1) Reported concentrations from all
previous monitoring, (2) degree of
variation in reported concentrations,
and (3) other factors which may affect
contaminant concentrations such as
groundwater pumping rates, changes in
the system's configuration, changes in
the system's operating procedures, or
changes in stream flows or
characteristics.
A "waiver by vulnerability
assessment" may take one of two forms.
The first involves a determination as to
.whether a given contaminant which
does not occur naturally is or was used,
manufactured, and/or stored in an area
nearby the system. If the contaminant is
not used, manufactured, and/or stored
nearby, the system can receive a "use
waiver." Second, if a "use waiver"
cannot be granted, a system may
conduct a thorough assessment of the
water source to determine the system's
susceptibility to contamination.
Susceptibility considers: (1) Prior
analytical and/or vulnerability
assessment result!!, (2) environmetai
persistence and transport (3) how well
the source is protected. (4) wellhead
protection program reports, and (5)
elevated nitrate levels. Systems with no
known susceptibility to contamination
(based upon an assessment of the above
factors) may be granted a "susceptibility
waiver."
All waivers must be granted on a
containinant-by-contaminant basis.
However, systems and States will find it
economical to apply for and grant the
waiver for those contaminants that may
be analyzed using the same analytical
methods. This packaging of assessment:
and State decision making will yield *
significant cost savings to both systems
and State primacy programs.
Waivers for the SOCs and VOCs.may
" be granted after the system conducts a.
vulnerability assessment and the State
determines the system is not vulnerable
based on that assessment. A waiver
must be renewed during each
compliance period. Waivers for
inorganic contaminants may be granted
for up to nine years. If a system does not
receive a waiver by the beginning of the
year in which it is scheduled to monitor.
it must complete the base monitoring .
requirement.
One change that EPA is adopting in
5 142.92 is that EPA may rescind
waivers issued by a State where the
Agency determines that the State has
issued a significant number of
inappropriate waivers. EPA does not
intend to utilize this provision except in
special situations where the State has.
not followed its own established and
EPA-approved protocols and procedures
• (see also the discussion on State
primacy requirements). If a waiver is
resinded. the system must monitor in
accordance with the base requirements
in today's rule.
f. Vulnerability assessments. EPA
received numerous comments on the
.issue of vulnerability assessments. In
the July 1990 Notice. EPA requested
comment on several alternatives for the
process of making vulnerability
decisions. One option involved requiring
States to assess the overall
hydrogeological vulnerability of each
water source supplying a PWS instead
of making contaminant-specific
determinations for each contaminant at
each PWS. Another option was to
assess the overall use of each
contaminant within specific regions,
focusing on potential sources of
contamination within a defined region.
EPA also requested comment on
whether systems should be required to
monitor for all contaminants that are
subject to the same analytical technique.
EPA proposed to allow States to
conduct area-wide assessments (based
on contaminant use information) or one
assessment of the water source
susceptibility to contamination (based
on hydrogeological information).
Commenters generally supported the
use of vulnerability assessments as a
first step in lieu of requiring all systems
to monitor. Different opinion! were
expressed regarding how to conduct
these assessments.
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Fedni
/ VoL 57. No. 138 / Friday. July 17. laaz / Rulea tad RegaUtkra
Some cootmenter* Indicated mat EPA
should provide detailed guidelines that
State* would use to make vulnerability
determinations. Example* cited included
the development of environmental fate
dccuments. identification and
characterization of the available sources
of information regarding the presence of
contaminants, and disposal facilities- " '
that nay impact water sources, among
others. Other commenters questioned
whether State agencies would have
sufficient financial and human resources
to collect the necessary information to
conduct an assessment of a water
system's vulnerability.
EPA has decided that a detailed
protocol for what is usually a very site-
specific analysis is not appropriate.
Instead. EPA desires that each State
develop its own specific vulnerability
assessment procedures that use the
general guidelines established by EPA.
The Agency believes that the States are
in the best position to develop detailed
protocols. If a State chooses not to
develop these procedures, systems
cannot receive waivers and must
monitor at the base requirements.
In the proposal EPA listed the
following criteria systems must consider
in conducting vulnerability assessments
for SOCs: Previous analytical results;
proximity of the system to sources of
contamination; environmental
persistence: protection of the water
source; and nitrate levels as an indicator
of potential contamination by pesticides.
For VOCs. the criteria were previous
monitoring results, number of people
served, proximity to a large system.
proximity to commercial or industrial
use. storage or disposal of VOCs, and
protection of the water source.
EPA received comments OQ the
process of how to make vulnerability
decisions. Comments ranged from
allowing the use of area-wide
assessment to contaminant-specific
assessment for individual supplies. One
commenter suggested combining two
options proposed (assessing the overall
hydrological vulnerability of the water
supplies and assessing the overall
contaminant use). EPA agrees with this
comment and. as part of tie earlier
rulemaking for 36 contaminants, has
made several changes to the
vulnerability assessment criteria and the
process to simplify the procedure {56 FR
3562]. Today's rule also adopts these
changes. First, a two-step waiver
procedure is available to all systems.
Step *1 determines whether the
contaminant that does not occur
naturally is or WAS used, manufactured
stored, transported, or disposed of in the
area. In the case of some contaminants
an assessment of the contaminant's use
in the treatment or distribution of water
may also be required. "Area" is defined
as the watershed area for a surface
water system or the zone of influence
for a groundwater system and includes
effects in the distribution system.
If the State determines that the
contaminant was not-used.
manufactured, stored, transported, or
disposed of in the area, then the system
may obtain a "use" waiver. If the State
cannot make this determination, a
system may not receive a "use" waiver
but may receive a "susceptibility"
waiver, discussed below. Systems
receiving a "use" waiver are not
required to continue on to Step «2 to
determine susceptibility. EPA
anticipates that obtaining a "use"
waiver will apply mostly to the SOCs
where use can be determined more
easily than for VOCs. Obtaining a "use"
waiver for the VOO will be limited
because VOCs are used extensively in
the United States. If a "use1' waiver
cannot be given, a system may conduct
an assessment to determine
susceptibility. Step *2.
Susceptibility considers prior
occurrence and/or vulnerability
assessment results, environmental
persistence and transport of the
chemical the extent of soorce
protection, and Wellhead Protection
Program reports. Systems witfc no
known "susceptibility" to contamination
based upon an assessment of me above
criteria may be granted a waiver by the
State. If "susceptibility" cannot be
determined, a system is not eligible for a
waiver. A system must receive a waiver
by the beginning of the calendar year in
which it is scheduled to begin
monitoring.
Several comroecters requested that
EPA permit "area wide" or geographical
vulnerability assessment
determinations. Though EPA at this time
is skeptical that "area wide"
determinations can be conducted wira
sufficient specificity to predict
contamination over a large area, the
final rule allows this option when State*
submit their procedure* for conducting
vulnerability assessments to determine
"use" waivers.
EPA's goal is to combine vulnerability
assessment activities in other drinking
water programs with today's
requirements to create efficiencies. EPA
also desires to use the results of other
regulatory program requirements, sndj
as Wellhead Protection Assessments, to
determine a system's vulnerability to
contamination. Systems and States may
schedule today's assessments with
sanitary surveys required under the
Total Cdiform Rule {54 FR 27546J
watershed-assessments, and othei' water
quality inspections so that ail
regulatory, operational, and managerial
objectives are met at the same time.
In the July 25.1990 Notice. EPA
solicited comments on whether the
contaminant source assessments.
conducted under State Wellhead '
Protection Programs (see section 1428 of
the SDVVA) could be used for the
vulnerability assessments and what the
relationship of the two assessments
should be. Commenters were supportive
of this concept but requested that
specific guidance be developed to
determine how this might be
accompliohed and where it is
appropriate.
EPA intends to issue a guidance that
will give flexibility to States in
conducting vulnerability assessments
and allow them and local public water
systems to meet these and similar
requirements under the Wellhead
Protection Program, satisfying the
requirements of both programs with one
assessment Additionally, this combined
assessment approach may be used to
meet similar requirements under the
evolving Underground Injection Control
(UIC)—Shallow Injection Well Program.
g. Relation to the Wellhead Protection
fWHPf program. As stated in dve
January 1991 Notice, the Agency plans
to integrate particular elements of the
Public Water System. Wellhead
Protection, and U1C programs related to
contaminant source assessments around
public water supply wells. Specifically,
the Agency plans to prepare a gwdance
document on groundwater contaminant
source assessment that merges the
vulnerability assessment of the PWS
program for SOCs and VOCs with the
wellhead delineation and contaminant
source which can be used to establish
priorities of UIC wells. This integration
is expected to assist State and local
drinking water program managers
responsible for groundwater supplies to
more efficiently and effectively
administer the portion of their program*
addressing source protection and will be
the basis for determining monitoring
frequency. The guidance will give States
flexibility in revising vulnerability/
contaminant scarce assessments.
Section 1420 of the SOWA requires
each State to submit a WHP program for
EPA review and approval in order to be
eligible for grant funds to support the
State's wellhead protection efforts. The
implementation of WHP programs by
States may be phased in to allow
resource* to be ased most effectively.
This matter can be addressed in the
State WHP submittal.
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Federal lUgtater / Vol. 57. No. 138 / Friday. July 17. 1992 / Rales and Regulation* 31823
When States submit WHP programs
for approval in the future, program
documents should address how the
State will phase requirements for
Wellhead Protection Areas (WHPAs)
with other PWS regulations. In some
States, to be most effective, this program
integration may need to be
accomplished-through1 a coordinating •••
agreement or other mechanism among
several State agencies. The guidance
would allow States to tailor their
program provisions to conditions in the
States, within broad guidelines.
Information from the other related
groundwater programs (such as
Superfund. RCRA) will be useful in this
assessment. This information also
includes identification of sources not
regulated under Federal programs, but
perhaps regulated by States, such as
septic tanks. Therefore. States may be
able to meet similar requirements of
these three programs through following
a general set of guidance procedures.
A State may choose from several
methods to delineate WHPAs. As long
as the method is determined to be
protective, a State may choose a
simplified method described in
"Guidelines for the Delineation of
Wellhead Protection Areas" |USEPA.
1987a). If a State desires more
information for use in the decision-
making process, it may choose more
sophisticated methods identified in the
"Guidelines." EPA has made available
to States and local agencies computer
software and training for use of the
"Guidelines" to make the process of
VVHPA delineation less difficult.
WHPAs may incorporate recharge
areas as long as they are within the
jurisdiction of the agencies identified in
the EPA-approved programs. However,
WHPAs must meet the requirements of
this rule if they are to be used to make
monitoring waiver determinations. The
State cannot accept a WHP program in
lieu of a vulnerability assessment if the
' recharge area is not covered to meet all
the requirements of this rule.
Once a WHPA is delineated, a State
may desire to apply a range of
assessment measures to define
hydrogeologic vulnerability within the
delineated area. A State may decide on
a method of assigning priorities to the
public water systems based-on
vulnerability, size, or other criteria
acceptable to EPA.
EPA's Ground-Water Protection
Division has developed a document
"^"entitled "Managing Ground Water
• Contaminatio'n Sources in Wellhead
Protection Areas: A Priority Setting
Approach" [USEPA. 1991hJ to help
States and local water supply managers
prioritize potential contaminant sources
in carrying out their programs for
resource protection, a concern of one
commenter. This system could also be
used in setting monitoring priorities but
was not designed specifically for that
application. The States may use the
regulatory mechanisms available to
them (e.g.. RCRA permits, NPDES
. permits) to determine the point sources; '
of regulated, and potentially
contaminating, substances in or near
areas needing protection, such as
wellhead and recharge areas.
h. Ground water'policy. The Agency
now has a new. integrated ground-water
policy. In July. 1982. EPA established a
Ground-Water Task Force to review the
Agency's ground-water protection
policies. The outcome of this effort is the
Ground-Water Task Force Report, which
includes EPA's Ground-Water
Protection Principles [USEPA. 1991e).
The Principles are intended to foster
more effective and consistent decision-
making in all Agency decisions affecting
ground water.
With respect to prevention, the •
Principles call for ground water to be
protected to ensure that the nation's
currently used and reasonable expected
drinking water supplies, both public and
private, do not present adverse health
effects and are preserved for present
and future generations. Ground water
should also be protected to ensure that
ground water that is closely
hydrologically connected to surface
waters does not interfere with the
attainment of surface water quality
standards, which are designed to protect
the integrity of associated ecosystems.
Ground-water protection should be
achieved through a variety of means
including: pollution prevention programs
aimed at eliminating and minimizing the
amount of pollution that could
potentially affect ground water, source
control, siting controls, the designation
of wellhead protection areas and future
water supply areas, and the protection
of aquifer recharge areas. Efforts to
protect ground water must consider the
use, value, and vulnerability of the
resource, as well as social and economic
values.
With respect to remediation, the
Principles call for activities to be
prioritized to minimize human exposure
to contamination risks first, and then to
restore currently used and reasonably
expected sources' of drinking water and
ground water closely hydrologically
connected to surface waters, whenever
' such restorations arc practicable and
attainable.
With respect to Federal. State, and
local responsibilities, under the
Principles, the primary responsibility for
developing and Implementing
comprehensive ground-water protection
programs continues to be vested with
the States. An effective ground-water
protection program must link Federal.
State, and local activities into a
coherent and coordinated plan of action.
EPA should continue to improve
coordination of ground-water protection.:
efforts within-Jhe Agency and with other
Federal agencies with ground-water
responsibilities.
This rule responds to the Ground-
Water Protection Principles in the
following ways. With respect to the
Principles' emphasis on prevention, this
rule sets MCLs and monitoring
frequencies for 18 synthetic organic and
five inorganic chemicals. These MCLs
will be used for ground water protection
(i.e.. as an indication of possible need
for source control) as well as surface •
water protection. The rule also
recognizes Slate wellhead protection
areas as a method of prevention and a
basis for granting waivers.
With respect to the allocation of
Federal. State, and local responsibilities,
this rule gives States the authority to
grant reductions in monitoring
frequency, based on a vulnerability
assessment. The guidance document for
this rule will give flexibility to the States
in conducting vulnerability assessments.
As a method of coordination among the
PWS. UIC. and Wellhead Protection
Programs, the guidance document will
allow States to use the methods and
approaches of the Wellhead Protection
Program in meeting the requirements for
vulnerability assessments.
i. Initial and repeat base monitoring.
Initial monitoring is defined as the first
full three-year compliance period that
occurs after the regulation is effective.
As described in the January 1991 Notice
[56 FR 3564], under the standard
monitoring framework. States have
flexibility to schedule monitoring for
each system during the three-year
compliance period. As discussed earlier.
all systems must monitor at the base
monitoring frequency unless a waiver is
obtained. The initial monitoring period
for today's regulation begins.fanuary 1,
1993 and ends December 31,1995 for
public water systems having 150 or more
service connections. For systems having
less than 150 connections, the initial
monitoring period will be from fanuary
1.1996 through December 31.1998. After
the system fulfills the initial (or first)
base monitoring requirement, it must
monitor at the repeat base frequency.
Generally the repeat base frequency is
the same as the initial monitoring
frequency but in some instances the
-base monitoring frequency may be
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31B24 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
reduced baaed on previous analytical
results. '
Also, under today s rule, EPA is
requiring the Stales to establish a
sampling schedule that may result in
approximately one-third of the systems
monitoring during reach of the three
years of a compliance period at the
State's discretion. States will have the •
flexibility to designate which systems
must monitor each year based upon
criteria such as system size.
vulnerability, geographic location, and
laboratory access. EPA believes that
allowing States the discretion to
schedule monitoring for each system
during the compliance monitoring period
will enable States to manage their
drinking water programs more
efficiently.
In cases where EPA is the primacy
authority for today's regulation (i.e..
where the Slate has not adopted
regulations corresponding to the
NPDWRs in today's rule by its effective
date, and in States and on Indian lands
where EPA retains primary enforcement
responsibility), systems will be required
lo complete monitoring within 12 months
after notification by EPA. In such cases.
EPA intends to use a prioritizing scheme
similar to the kind that the States will
use. This should minimize the disruption
to the regulated community when the
State does adopt the requirements and
begins to develop its own monitoring
schedules for systems within the State.
Once a system is scheduled for the
first, second, or third year of a
compliance period, the repeat schedule
is set for future compliance periods. For
example, if a system is scheduled by the
State lo complete the initial base
requirement by the end of the first year.
all subsequent repeat base monitoring
for lhal syslem musl be completed by
the end of the first year in the
appropriate three-year compliance
period. This is necessary to prevent
systems from monitoring in the first year
of the first compliance period and the
third year of the repeat base period.
4. Monitoring Frequencies
a. Inorganics—(I) Initial and repeat
base requirements. In the July 1990
Notice. EPA proposed that surface water
systems monitor annually and
groundwater systems monitor every
three years. Some commenters
supported lhal frequency. Other
commenters suggested thai the Agency
should allow waivers.based on
vulnerability assessments for the initial
round of monitoring. The monitoring
frequencies in today's rule are identical
to these proposed frequencies. EPA
disagrees with commenters regarding
the issuance of waivers in lieu of an
initial round of monitoring. A reduction
in monitoring frequency may be
appropriate if the levels found are
reliably and consistently below the MCL
(see discussion on decreased monitoring
below). Systems with 150 or more
service connections will be required to
take the initial base sample for each
inorganic during the initial compliance
period of 1993 to 1995 (subject to State
scheduling). Surface water systems with
150 or more service connections that are
on an annual sampling schedule are
required to start in 1993. '
(2) Increased monitoring. In the
January 1991 Notice. EPA added a
requirement that systems that exceed
the MCL (either in a single sample or
with the average of the original and
repeat sample) and which, consequently.
are out of compliance must immediately
(i.e.. the next calendar quarter after the
sample was taken) begin monitoring
quarterly. Systems must continue to
monitor quarterly until the primacy
agent determines that the system is
"reliably and consistently" below the
MCL Groundwater systems must take a
minimum of two samples and surface
water systems must take a minimum of
four samples after the last analytical
result above the MCL. before the Stale
can reduce monitoring frequencies back
to the base requirement (i.e.. annually
for surface systems and every three
years for groundwater systems).
EPA made this change for several
reasons. First, it is consistent with the
monitoring requirements contained
elsewhere in this rule that more frequent
monitoring occur in instances of non-
compliance. Second. EPA believes that
systems that are out of compliance
should, in general, monitor more
frequently to determine the extent of the
problem. If EPA has not made this
change, groundwater systems that
exceed the MCL could continue to
monitor every three years. EPA believes
the previous frequencies for ground and
surface systems were not adequale lo
protect the public in those cases where
systems exceeded the MCL. :
(3) Decreased monitoring. In both the
May 1989 and the July 1990 Notices, EPA
proposed that systems be allowed to
reduce the monitoring frequency to no
less frequent than once every 10 years
between monitoring episodes provided a
syslem had previously taken ihree
samples that were all less than 50
percent of the MCL Stales would base
their decision on prior analytical results.
variation in analytical results, and
system changes such as pumping rates
or stream flows/characteristics.
EPA received numerous comments on
Ihe 50 percenl trigger for reduced
monitoring with most commentera
opposing Ihe 50 percenl Irigger. calling it
arbitrary. In the January 1991 notice.
EPA decided to eliminate the 50 percent
trigger and change the condition for
reduced monitoring to require three
compliance samples, all of which are
"reliably and consistently" less than the
MCL to give the.States-additional.;. • '••
flexibility to decide which systems are
eligible for reduced monitoring. Systems
meeting this criterion are also eligible
for reduced monitoring for the
contaminants in today's rule. While
States have discretion in making this
delerminalion. EPA believes that as a
minimum, all individual samples should
be below the MCL before the
determination should be made.
Most commenters supported the 10-.
year time frame as a reasonable
monitoring frequency for reduced
monitoring. Because EPA has adopted a
3/6/9-year compliance cycle. EPA has
changed the maximum reduced
monitoring frequency from the proposed
10 years to 9 years to gain consistency
in its regulations. EPA believes this
change will have a minimal impact on
systems..EPA is requiring at least one of
the three previous samples to be taken
since January 1.1990. The other two
samples could be taken at any time after
January 1,1988. Because the reduction in
monitoring to every nine years begins in
the 1993-2001 compliance cycle. EPA
believes that one sample must be recent
(i.e., taken after January 1.1990 for
systems scheduled to monitor in 1993) to
preclude ^unduly long time frames
occurring between samples. Data
obtained to satisfy monitoring
requirements for unregulated
contaminants specified in the January
1991 notice may be used to reduce the
monitoring frequencies. Systems
receiving a waiver may monitor at any
time during the nine-year compliance
cycle, as designated by the State.
b. Cyanide. In the July 1990 Notice.
EPA proposed monitoring requirements
for Ihe IOCS applicable lo all community
(CWS) and non-transienl non-
communily waler syslerris. Several
commenters disagreed with Ihe
requiremenl lo monitor for cyanide at
non-vulnerable systems. They argued
that the main sources of cyanide
contamination are industrial and
manufacturing processes, not natural
occurrence, and thai il would be more
appropriate lo regulale cyanide under
the requirements that apply to synthelic
organic compounds (SOCs), which
dislinguish vulnerable and non-
vulnerable systems.
The Agency agrees with these
commenters and has changed the
requiremenl for cyanide lo require only
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Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Kegu/atfona " 31825
vulnerable systems to monitor, provided
a waiver (by vulnerability assessment)
is available and has been granted by the
State.
Other commenters stated that the
monitoring requirements for all the lOCs
in today's notice should apply to
vulnerable systems only, and that EPA,
should allow waivers based on
vulnerability assessments for the initial
round of monitoring. EPA disagrees with
these commenters (except for cyanide
because it does not occur naturally at
concentrations near the MCL) because
some minimum monitoring requirements
for the inorganic contaminants will
provide a baseline of data on the natural
background levels expected for these
contaminants. Systems may qualify.for
reduced monitoring once a baseline of
data shows levels that are reliably and
consistently below the MCL thus
decreasing the monitoring burden. .
c. Volatile Organic Contaminants
(VOCs)—(I] Initial and repeat base
requirements. In the rule promulgated in
July 1987 setting MCLs for eight VOCs,
. EPA required all systems to take four
consecutive quarterly samples.
Groundwater systems that conducted a
vulnerability assessment and were
judged not vulnerable, however, could
stop monitoring after the first sample
provided no VOCs were detected in that
initial sample.'Repeat frequencies for all
systems vary by system size, detection,
and vulnerability status.
On July 1.1991. EPA amended the
monitoring requirements for VOCs to
streamline the requirements and to
make all VOC requirements consistent
[56 FR 30267]. For the contaminants in
today's rule, the July 1990 proposal
made distinctions in base requirements
for VOCs between ground and surface
water systems, less than and more than
500 service connections, and vulnerable
and non-vulnerable systems. In today's
final rule, to be consistent with the July
1991 rule, and for the reasons discussed
there [56 FR 30267], EPA is requiring all
groundwater systems as well as surface
water systems to initially take four
quarterly samples for the VOCi
(dichloromethane, 1,2,4-
trichlorobenzene, and 1.1,2-
trichloroethane). regardless of size or
vulnerability status. Systems that do hot
detect VOCs in the initial round of four
quarterly samples are required to
monitor annually beginning in the next
• calendar year after quarterly sampling is
completed. For example, systems which
complete quarterly monitoring in
calendar year 1993 are required to begin
annual monitoring in 1994. The State
may allow groundwater systems, which
conducted three years of sampling and
have not detected VOCs to take a single
sample every three years thereafter. The
reasons for these changes are further
explained in the January 1991 notice [56
FR 3566].
In the May 1989 proposal covering 38
contaminants. EPA requested comment
on whether vulnerable-systems may
take only one sample if no VOCs are
detected in the initial year of
monitoring. EPA's intent was to require
quarterly sampling in vulnerable
systems, but most commenters opposed
a change to more frequent monitoring.
Based on the comments received on that
notice. EPA specified in the January
1991 final rule for 33 of the 38
contaminants that vulnerable systems
will be required to take one annual
sample (instead of four quarterly
samples) if no VOCs were detected in
the initial (or subsequent) monitoring.
For consistency, EPA has adopted this
same requirement for the VOCs in
today's rule.
(2) Increased monitoring. In the
proposal, systems detecting VOCs
(defined as any analytical result greater
than 0.0005 mg/1) were required to
monitor quarterly. In today's rule. EPA
is requiring systems that detect VOCs to
monitor quarterly until the State
determines that the iiystem is "reliably
and consistently" below the MCL.
However, groundwater systems must
take a minimum of two samples and
surface water systems must take a
minimum of four samples before the
State may reduce the monitoring to the
base requirement (i.e., annual sampling).
Systems remain on an annual
sampling frequency even if VOCs are
detected in subsequent samples, unless
an MCL is exceeded (or if the State
otherwise specifies). In this case, the
system returns to quarterly sampling fri
the next calendar quarter until the State
determines that the new contamination
has decreased below the MCL and is
expected to remain reliably and
consistently below the MCL This
determination shall again require a
minimum of four quarterly samples for
surface water systems and two
quarterly samples for groundwater
systems.
EPA has made thin change because
some systems may detect VOCs at a
level slightly above the detection limit
EPA believes that where the State can
determine that contamination is
"reliably and consistently" less than the
MCL those systems should be able to
return to the base monitoring
requirement (i.e^ annuallyL. Giving
States the discretion to determine
whether systems meet this criterion may
allow States to give monitoring relief to
some systems.
(3) Decreased monitoring. States may
grant waivers to systems that are not
vulnerable and did not detect VOCs
while conducting base monitoring.
Vulnerability must be determined using
the criteria specified above in-the
•discussion of vulnerability assessments.
EPA anticipates that most systems will
not be able to qualify for a "use" waiver
because of the ubiquity of VOCs.
However, systems conducting an
assessment that considers prior
occurrence and vulnerability
assessments (including those of
surrounding systems), environmental
persistence and transport, source
protection. Wellhead Protection
Assessments, and proximity to sources
of contamination may apply to the State
for a "susceptibility" waiver. If the
waiver is granted, systems are required
to take one sample and update the
current vulnerability assessment during
two consecutive compliance periods
(i.e., six years). The vulnerability
assessment update must be completed
by the beginning of the second
compliance period. EPA has increased
the time frame from five to six years to
bring the five-year monitoring frequency
in the proposal in line with the 3/6/9-
year frequencies specified in the
•standard monitoring framework.
States have the discretion to set
subsequent frequencies in systems that
did not detect VOCs in the initial round
of-four quarterly samples and that are
designated as not vulnerable based on
assessment. The repeat monitoring
frequency for groundwater systems
meeting this criteria shall be not less
than one sample every six years as
discussed above. For surface water
systems meeting this criteria, the repeat
frequency is at State discretion.
d. Synthetic Organic Chemicals
(SOCs)—(1) Initial and repeat base
requirements. In the proposal, systems
were not required to monitor for the
non-volatile SOCs unless the State, on
the basis of a vulnerability assessment,
determined the system to be vulnerable.
Once determined vulnerable by the
State, a system would be required to
take four consecutive quarterly samples,
EPA requested comment on an
alternative approach that would require
all systems to monitor for all
contaminants. As discussed below,
today's requirements specify that all
systems monitor for all SOCs by taking
four quarterly samples every three
years, unless decreased or increased
monitoring requirements apply. All
systems-are eligible for waivers from the
quarterly monitoring requirement as
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31826 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
discussed in the section on decreased
monitoring below.
Most comments on the proposal
revolved around two issues—the
requirement that systems monitor
quarterly and the requirement that all
systems monitor at the time of highest
vulnerability. Many commenters staled
thai quarterly monitoring was not
necessary to detect changes in
contamination Many ccmmenters
recommended annual monitoring for
pesticides. After reviewing the
information and comments submitted.
EPA believes that quarterly monitoring
remains the best scheme lo determine
contamination. Occurrence information
available to EPA indicates that seasonal
fluctuations from runoff and
applications of pesticides may occur:
thus, quarterly monitoring is better than
annual monitoring to determine
pesticide contamination. In some cases.
Slates may consider it appropriate to
require monitoring at greater
frequencies than those specified by
today's rule to better determine
exposure. States have the option to
require monitoring at greater
frequencies than the federal minimums
in today's rule. Systems, of course, may
always monitor more frequently when
they deem it prudent.
Most comorienters opposed the
requirement to monitor at the time of
highest vulnerability, stating the highest
vulnerability, stating that highest
vulnerability cannot be predicted or
determined. Several commenters stated
that the requirement to monitor at the
time of highest vulnerability was
unenforceable. EPA agrees and
eliminates this requirement from today's
rule. However. States are advised to
examine sampling practices of systems
to assure that periods of likely
contamination are not avoided. This is
especially true for surface water
systems monitoring for pesticides after
rainfall and/or application of pesticides.
EPA proposed that systems conduct
repeat monitoring every three or five
years, depending on system size and
ground/surface distinctions.- In today's
rule, the repeat monitoring frequency for
all systems is set at four consecutive
quarterly samples each three-year
compliance period, unless decreased or
Increased monitoring requirements
apply. EPA has made several
adjustments For systems that do not
delect contamination in the initial
compliance period. After the initial
monitoring round is completed, systems
that serve 3.300 or more persons may
reduce the sampling frequency to two
samples In one year during each
compliance period. Systems serving less
than 3.300 persons may reduce the
sampling frequency to one sample per
compliance period. EPA has increased
the frequency at which small systems
must monitor in this rule from every five
years to every three years, because EPA
believes that this change will offer
greater health -protection/ EPA- believes
that every five years is too long an
interval to determine changes in
consumer exposure.
EPA has made the granting of "use"
waivers for pesticides easier in this rule
by permitting States to grant "area
wide" or "Statewide" waivers based
upon pesticide use information. EPA
anticipates that many systems will be
able to obtain a "use" waiver.
Therefore, the impact of the increased
monitoring frequency discussed in the
above paragraph should be minimal. For
those systems not able to obtain a
waiver (i.e.. vulnerable systems), EPA
believes it is appropriate to monitor at
three-year intervals to determine
contamination.
(2) Increased monitoring. EPA
proposed that systems with 500 or less
service connections that detect SOCs
contamination monitor annually, while
systems with more than 500 service
connections that detect SOCs would
monitor quarterly. EPA defined
detection as greater than 50 percent of
the MCL Many comments revolved
around the 50 percent trigger. Consistent
with the above discussion concerning
VOCs. EPA is redefining detection for
SOCs to mean the method detection
limit (as specified in the approved
analytical method). EPA believes it is
appropriate to use the method detection
limit as the trigger for increased
monitoring because detection implies
that the potential for increasing
contamination exists. Consequently,
additional monitoring is required to
determine the extent and variability of
SOCs contamination. Jn today's rule, all
systems that detect SOCs must comply
with the baseline monitoring
requirements (i.e.. waivers are-not
available).
As described in the proposal, upon
detection, all systems must immediately
begin quarterly monitoring. The State
may reduce the requirements to annual
monitoring for SOCs after determining
that samples are "reliably and
consistently" below the MCL. A
reduction to annual monitoring may
occur after a minimum of two samples
for groundwater and four samples for
surface water systems. After three years
of annual monitoring which remains
"reliably and consistently" below the
MCL. systems can return to the base
monitoring requirement for SOCs (i.e..
four quarterly samples every three
years).
(3) Decreased monitoring. Systems
that obtain a waiver from the monitoring
requirements are not required to
monitor. All systems are eligible for
waivers in the first Hires-year
'compliance period of 1993 to 1995. AS
discussed above. EPA has simplified the
vulnerability assessment procedures bv
allowing the system to assess whether"
the contaminant has been used.
transported, mixed, or stored in the
watershed or zone of influence. Where
• previous SOCs use in the area can be
ruled out, systems may apply to the
State for a use waiver. EPA's intent in
promulgating this change is to make it
easier for systems to obtain waivers in
those situations where the chemical has
not been used. States may be able to
determine that the entire State or
specific geographic areas of the Stale
have not used the contaminant and
consequently grant "area wide"
waivers. Systems that cannot determine
use may still qualify for a waiver by
evaluating susceptibility according to
the criteria discussed in the VOC
section above. Waivers must be
renewed every three years.
e. Sulfates. Some commenters
believed that systems violating the
sulfate MCL should not be required to
monitor quarterly, because sulfate levels
are stable, and additional monitoring
would provide no new information. EPA
has collected additional data on sulfate
levels and agrees with the comment.
However, as discussed above. EPA is
not setting a final MCL for sulfate today
and is. therefore, not setting final
monitoring requirements for sulfate. For
the time being, monitoring for sulfate
will continue to be required under the
provisions for monitoring of unregulated
contaminants established in the January
1991 rulemaking.
5. Other Issues
a. Compliance determinations. One
commenter opposed the use of a single
sample to determine compliance with
the IOC MCLs for systems that monitor
yearly or less frequently. The
commenter argued that this procedure
provides an advantage to the system
required to monitor quarterly, because if
an annual average.is the basis for
compliance an entire year may go by
before the system monitoring quarterly
is deemed out of compliance and public
notification is required, whereas the
system moriitbring annually is deemed
out of compliance immediately if it
violates the MCL once. The cemmenter
recommended that all systems monitor
-------
f VAL' 57. 'fk>.' 13B / 'Pti^ay, July 17. 1992"/ RuJes and tfeguJatiohs 3385
on a quarterly basis with compliance
based on a running average.
EPA believes that quarterly
•monitoring is not generally necessary for
the lOCs and is no longer requiring
initial quarterly monitoring. However, if
the system exceeds the MCL at any
sampling point, then the system is out of
compliance (based.on the original and.- •
one confirmation sample, at State
discretion) and quarterly monitoring is
thereafter required. For.those systems
monitoring more frequently than
annually, the Agency requires that if any
one sample would cause the annual
average to be exceeded, then the system
is out of compliance immediately and
public notification is required. In
addition, a system, if it wishes, may
apply to the State to conduct more
frequent monitoring of the lOCs than the
minimum frequencies specified in this
regulation (see § 141.23(h)). Under
§ 141.23(i), systems that are monitoring
at a greater than annual frequency
determine their compliance by a running
annual average of results.
EPA believes that this approach puts
emphasis on monitoring on those
systems that are of greatest concern
while providing cost savings to most
systems.
b. Confirmation samples. Several
commenters stated that collection of a
confirmation sample within 14 days of
the original sample is unrealistic. EPA
continues to believe that the 14-day
period is reasonable for the collection of
a confirmation sample since it is
important to get a conclusive '
determination of any MCL exceedance
as soon as possible. In addition, one
commenter stated that confirmation of
negative samples should not be required
due to cost constraints. In response, the
collection of confirmation samples is not
a federal requirement, but a State •
option. The Agency agrees that States
should consider costs in making
decisions about confirmation samples,
especially for negative results.
c. Compositing. EPA proposed to
allow systems, at the discretion of the
State, to composite up to five samples.
Compositing must be done in the
laboratory. Some commenters supported
compositing as a methodology to cut
costs. In this final rule, EPA is limiting
compositing among different systems to
only those systems serving fewer than
3.300 people. Systems serving greater
than 3,300 persons will be allowed to
composite but only within their own •
system. EPA also requested comments
on whether State discretion on
compositing is necessary or whether
systems can composite automatically
without State approval. Several Statei-
opposed this change; consequently, the •
final rule is unchanged from the
proposal. EPA believes that compositing
is to be used only when cost savings are
important and systems alone should not
make that determination. Today's rule
limits compositing to those
contaminants where theMDL is less
than one-fifth of the MCL, in order to
avoid situations where compositing of.
five samples would mask the presence
of a contaminant in one sample by
dilution with the other samples.
d. Polynuclear Aromatic
Hydrocarbons (PAHs). In the July 1990
proposal. EPA requested comments on
the following monitoring issues related
to the PAHs: (1) Should fluoranthene
and naphthalene be used as indicators
of the potential presence of carcinogenic
PAHs: (2) should EPA require sampling •.
at the tap: and (3) should PAH
monitoring be at State discretion if the
State bans the use of coal tar in
distribution systems. Below is a
summary of the comments on these
issues and EPA's response.
Use of indicators: Commenters
generally opposed the use of non-
regulated PAHs such as naphthalene
and fluoranthene to determine a
system's vulnerability to PAH
contamination and recommended that
systems monitor only for BaP (and any
other PAHs the Agency decides to
regulate). For the reasons stated earlier
in today's notice. EPA is promulgating
an MCLG and an MCL for BaP only at
this time. On reconsideration, EPA
agrees that naphthalene and
fluoranthene are not necessarily good
indicators for the presence of BaP in
water. On reconsideration of the data,
EPA acknowledges that BaP is much
less soluble than naphthalene and
fluoranthene, and has not been found to
co-occur with them. Therefore, EPA has
decided against the use of these PAHs
as indicators of BaP contamination in
drinking water. This is consistent with
the commenters' recommendations.
Samp/ing at the tap: EPA received
numerous comments on this issue. Most
commenters opposed sampling at the
tap, claiming that it is neither acceptable
nor appropriate to sample at the tap for
PAHs. These commenters argued that
coal tar. which may be a major source of
PAH contamination in the distribution
system, is-not used in home plumbing
and that the tap.is a location beyond the
control of the water utility. Some
commenters suggested, however, that
sampling in the distribution system.
downstream of the lined section of the
system, may be appropriate. One
commenter further stated that
monitoring for PAHs originating from
the distribution syatem should be a
"one-time effort" under worst case
conditions.
Elsewhere in today's rulemaking, EPf
has explained that it is regulating only
BaP Within the group of PAHs. MCLs
have not been set for other PAHs that
the proposal indicated EPA was
considering regulating.
Further, there are data indicating that
BaP does not leach from materials in the
water delivery system (i.e.. distribution
system pipe materials, storage tanks), at
noted by one commenter. Survey of data
on leaching of BaP from U.S. water
storage/distribution systems has
revealed that data are available for at
least 36 U.S. cities. In these studies
water samples were collected from the-
treatment site as well as from one or
more locations in the storage and/or
distribution system. The increase in
concentration of BaP from distribution
systems in these studies has ranged
from none to 2i9 ppt [Saxena et at.. 1978;
Robeck. 1978: Zoldak. 1978:
McClanahan. 1978: Alben. 1980: Basu et
al.. 1987). Laboratory studies involving
exposure of tap water to panels coated
with coal tar coating support these
findings [Alben, 1980: Lampo. 1980|.
Higher BaP concentration (78-110 ppt) in
the water was reported only in one
laboratory study where rigorous
leaching conditions not representing
actual distribution/storage system
exposure were used (Sorrell et al.. 1980|.
in addition, coal tar and asphaltic
linings are not generally used in home
plumbing which is usually copper.
galvanized, or plastic piping.
Based on these studies. EPA has
concluded that contribution of BaP from
coal tar-lined storage and distribution
systems is very small overall and is only
a small percentage of the final BaP MCL.
Therefore, EPA has decided that there is
no need to set controls for BaP
contributions from the materials in the
water delivery system. This
contaminant is appropriately controlled
by controlling its levels in source water.
as is true for the other contaminants in
today's rule. Consequently. EPA has
determined that there is no need for
today's rule to require monitoring at the
tap or anywhere else in the distribution
system.
Coal tar ban/States' discretion for
monitoring. Commenters generally
opposed banning the use of coal tar and
asphaltic linings in the distribution •
system and storage tanks at this time.
One commenter suggested that
additional evaluation of the potential
risks due to the use of coal tar linings in
water distribution systems is necessary
before recommending discontinuation of
their use. Another commenter stated
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31828
Fxfcral R*g»tor / Vol. 57. Na 138 / Friday, faiyl7, f992 ^ Riles and • Regulations
that the banning of. the use of coal tar
may not be warranted, especially in
light of the ubiquitousness of PAHs in
foodstuffs and consumer products. One
commenter indicated that its water
supplier had halted the further use of
coal tar materials in the late 1970s. This
commenter indicated it has found cost-
effective.alternatives for both pipes and.-
tanks.
As noted above, the Agency finds that
the contribution of BaP from coal tar
lined pipes and storage tanks is
generally very small relative to dietary
sources, as one commenter stated. It is
possible, however, that there may be
leaching of PAHs other than BaP due to
coal tar in the distribution system. Thus,
the Agency believes that States should
carefully evaluate any actions related to
this potential source of contamination
(such as banning the further use of coal
tar) to be sure that action is warranted.
With respect to State discretion
Concerning monitoring requirements if it
bans the use of coal tar, one commenter
stated that vulnerable systems should
still be required to monitor, while
n.iother commenter indicated that
monitoring should be at State discretion.
and a third commenter recommended
that monitoring at the Up be at State
discretion. EPA has carefully considered
these comments and is not requiring that
systems monitor for BaP in the
distribution system, as discussed above.
D. Variances and Exemptions
1. Variances
Under section 1415{a)(l)(A) of the
SDWA. EPA or a State that has primacy
may grant variances from MCLs to those
public water systems that cannot
comply with the MCLs because of
characteristics of their water sources. At
the time a variance Is granted, the State
must prescribe a compliance schedule
and may require the system to
implement additional control measures.
The SDWA requires dial variances may
only be granted to those systems that
have installed BAT (as identified by
EPA). However, in limited situations ft
system may receive a variance if it
demonstrates that the BAT would only
achieve a de minimi's reduction to
contamination (see 5 142.62(d)). Before
EPA or a State issues a variance, it must
find that the variance will not result in
an unreasonable risk to health.
Under section 1413(a)(4) of the Act.
States with primacy that choose to issut
variances must do so under conditions
and In a manner that is no less stringent
than EPA allows under section 1415.
defore a State may issue n variance, it
must find that there were no
opportumUe* for the system to (1) Join
another water system, or (2) develop
another source of water and thus
comply fully with all applicable drinking
water regulations.
The Act permits EPA to vary the BAT
established under section 1415 from that
established under section 1412 based on
a number of findings such as system
size, physical conditions related to -. • '••••
engineering feasibility, and the cost of
compliance. Paragraph 142.62 of this rule
lists the BAT that EPA has specified
under section 1415 of the Act for the
purposes of issuing variances. This list
mirrors the proposed list except that
oxidation (chlorination or ozonation) is
considered BAT for glyphosate, as
discussed in "Selection of Best
Available Technology" above. Tables 20
and 21 provide a list of the section 1415
BATs for the inorganic and organic
compounds in this rule.
TABLE 20.—SECTION 1415 BAT FOR
INORGANIC COMPOUNDS
Cnemtcal
BATs
Antimony- _ _ .
Becylkum _...._... ...__ .. ._._
CysnxJe _.._ .___ .... ___.
Niekal —„-—,„.,..,....
ThaJhum _ _ _
27
2567
5 7 10
• 56,7
57
Kff 10 BATs in TabJe 2:
'-Coaoulabon/FiRration (not BAT lor systems
with <500 service connections).
-ton Exchange.
-Urn* Softenng. (not BAT lor »>mms w«l
<500 service connections).
• Reverse Oimosft.
o.Chtormo.
'-Ultraviolet.
TABLE 21'.—SECTION 1415 BAT FOR
ORGANIC COMPOUNDS
Chemical
Benzo(a)pjren« . —
D*tapon_.
Dtcnforomttharw ... ,
Di(2-etn>«wxy<)adipaM -
di(2-
etnyttwxyQphthatate.
Dinosab
Oquat ......
EndotnaJJ .
Endrin ._ '. !.."...
GtypnosaM
HcmcMorocyc^o*
pentaoerw.
Oxamyl (Vyd*t»)
pjctorwn _„._.„ -......,
S*m*zsr*
1 . 1 i-TricWoro«th«n«_.
2.3.7.6-TCOO (Dioxin)_.
PTA«
- —-
X
X
X
X
GAC«
X
X
X
X
X
X
X
X
X
X
X
X
X
X
ox»
X
1 PTA-Pucfceo lower >ei«Boo.
* GAC-OranUar aOtalad ctrtx
* OX-Owtoton {ChtonnMon or Owna&an*.
2. Exemptions
Under section 1418(a), a State or EPA
may grant an exemption extending
deadlines for compliance with a
treatment technique or MCL if it finds
that (1) due to compelling factors (which
may include economic factors), the PWS
is unable to comply with the
requirement: (2) the exemption will not
result in an unreasonable risk to human
health: and (3) the system was in
operation on trie-effective date'of the'. •'•'•
NPDWR, or. for a system not in
operation on that date, no reasonable
alternative source of drinking water is
available to the new system.
In determining whether to grant an
exemption. EPA expects the State to
determine whether the facility could be
consolidated with another system or
whether an alternative source could be
developed. It is possible that very small
systems may not be able to consolidate
or find a low-cost treatment. EPA
anticipates that States may wish to
consider granting an exemption when
the requisite treatment is not affordable.
Under section 1416{b)(2)(B) of the Act,
an exemption may be extended or
renewed (in the cases of systems that
serve 500 or less service connections
and that need financial assistance for
the necessary improvements) for one or
more two-year periods provided that no
unreasonable risk to the health of
persons would result from granting the
exemption.
3. Point-of-Use Devices, Bottled Waters
and Point-of-Entry Devices
Under sections 1415(a) and 1416(b) of
the SDWA. when the State grants a
variance or exemption, it must prescribe
an implementation schedule and any
additional control measures that tha
system must take. States may require
the use of point-of-use (POU) devices,
bottled water, point-of-entry (POE)
devices and other mitigating devices as
"additional" control measures'if an
"unreasonable risk to health" would
otherwise exist Sections 1424>7 and
142.62 allow these measures as an
interim control measure while a
variance or exemption is in effect
4. Public^ Comments
EPA received several comments
regarding the issuance of variance* and
exemptions. Comments were concerned
about the high cost of the proposed BAT
technologies (reverse osmosis and Ion
exchange) for sulfate for small systems
that may need to obtain variances under
section 1415 of th« SDWA. One
commenter states that variances and
exemption!) are temporary and that
systems will still be required to comply
at some point This commenter further
states that any cost saving due to
granting of temporary variances or
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Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
311
exemptions must be reduced by the
costs of complying with the "interim
control measures" required under the
Act and the transaction costs of
documenting and applying for exempt
status.
Another commenter argued that
health protection is not ensured because
systems may be granted variances and -
exemptions due to the prohibitive cost
to implement available technology to
achieve lower sulfate levels. This
commenter recommended the use of a
monitoring program and public
notification for sulfates instead of an
MCL.
Two commenters stated that EPA
should allow States the discretion to
grant variances from the sulfate MCL for
all systems (large as well as small), as
long as the variance does not result in
an unreasonable risk to health. These
commenters recommend that concerns
about the water supply and availability
should be considered to be pertinent
"characteristics of raw water sources"
and that provision of public information
and alternate water supplies for
sensitive populations could be regarded
to be appropriate BATs for granting
variances.
EPA Response: In response to the
commenters concerned about the high
costs of reverse osmosis and ion
exchange for sulfate removal, the
Agency agrees that these costs are high
for very small systems. A majority of the
systems which would have been
affected had EPA not deferred the
sulfate rule serve 500 or less persons.
Exemptions for these systems could
have been renewed as long as the
system qualifies for an exemption under
section 1416(b) of the SDWA. The costs
given in the Regulatory Impact Analysis
(RIA) for regulating sulfate assumed no
variances and exemptions are granted
(i.e., that all systems treat). Thus, the
Agency believes that costs to meet a
sulfate regulation would have been
lower than those projected in the RIA,
after consideration of costs associated
with granting variances and exemptions.
In response to the commenter that
alleged lack of health protection
because variances and exemptions will
be granted, a variance or exemption can
only be granted if it will not result in an
unreasonable risk to health. In addition,
the associated public notification
requirements whenever an MCL
exceedance occurs would have provided
additional protection to consumers.
In response to the commentere that
recommended allowing the States
discretion to grant variances to all
systems regardless of size. States do
have the discretion to grant variances to
all public water systems that cannot
comply with the MCLs because of
characteristics of their source waters.
Variances generally can only be granted
if the systems have installed BAT and
have failed to meet the MCL. In granting
variances, the State may prescribe
interim control measures such as public
information or provision of alternate -. . v
water supplies (e.g.. bottled water). •
The population served by transient
water systems is likely to be at greatest
risk of suffering from the adverse effects
of sulfate. Because populations that
regularly consume! water containing
sulfate will acclimate to its effects, it is
people using higher sulfate water on a
transient basis that make up the.
population at risk. This group is largely
travelers, i.e., visitors to communities or
facilities that are non-transient non-
community public water systems, or •
visitors to facilities such as gas stations.
campgrounds or other recreational
facilities that serve an almost
exclusively transient population. It is
this latter group of facilities or public
water systems that are most likely to
serve water to non-acclimated persons
who are at risk from high sulfate.
Sulfate's high treatment cost, low risk.
and impact primarily on the transient
consumer, combine to create a different
set of regulatory challenges than posed
by most other drinking water
contaminants. For these reasons, EPA is
deferring the sulfate standard for a
current undetermined period.
Specifically, EPA is seeking to extend
the legal deadline for establishing the
sulfate standard for a period that would
allow the Agency to resolve the
following issues: (1) Whether further
research is needed on how long it takes
infants to acclimate to high sulfate-
containing water, (2) whether new.
. regulatory approaches need to be
established for regulating a contaminant
whose health effect is confined largely
to transient populations, and (3) whether
the Agency should revise its definition
of Best Available Technology for small
systems (i.e., what should be considered
affordable for transient noncommunity
water systems). During this deferral
period, the Agency also intends to
consider ways to expedite the process
for granting potential exemptions and
variances to ease the impact of these
. regulations on small systems. Also in
the interim, EPA plans to issue a Health
Advisory for sulfate and to encourage
States where sulfate levels may be high
to conduct additional monitoring and
encourage the use of alternative water
supplies where appropriate.
E. Public Notice Requirements
1. General Comments
Two comments were received on the
general issue of public notification
requirements. One commenter stated
that the required public notifications
should, provide a more accurate and v
balanced explanation of potential healt
effects. The second commenter stated
that public notification should not be
required unless contaminant levels
remain excessive after BAT has been
installed. '
EPA Response: EPA believes that the
public notification language prescribed
is, and should be, simple and non-
technical in nature while providing
sufficient information to the public
about the health implications. EPA
believes that the statements are
accurate and balanced. The Agency alsc
believes that the public has the right to
know whenever there is a violation of a
standard. The public water system may
supplement the notice with additional
information such as the steps being
taken to meet the standards as long as
the notice informs the public of the
health risks which EPA has associated
with violation of the standards and the
mandatory health effects language
remains intact.
2. Contaminant-Specific Comments
Two commenters provided specific
suggestions on changes for the public
notification language for several
contaminants. These changes were
editorial in nature.
EPA Response: EPA has made most of
the changes suggested, as appropriate.
F. Secondary MCL for
Hexachlorocyclopen tadiene
EPA proposed a secondary maximum
contaminant level (SMCL) based upon
odor detection levels for
hexachlorocyclopentadiene (HEX). Odor
detection for this organic chemical has
been reported at levels lower than the
MCL of 0.05 mg/1. The July 1990 notice
proposed to set the SMCL for this
compound at 0.008 mg/1.
EPA received two comments on the
proposed SMCL for HEX. One
commenter stated that an SMCL for
HEX will "erode the public's confidence
in the overall quality of the drinking
water," and recommended against an
SMCL for this compound. Another
commenter opposed the proposed SMCL
alleging it is based on an inadequate
experimental basis. The commenter
argued that the literature citation
[Amoore and Hautala. 19S3J was^based
on theoretical extrapolation (from air
odor thresholds), and the levels have not
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31830 Federal RegUtar / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
been confirmed by any published
literature.
After reviewing the public comments.
EPA has decided to defer promulgating
an SMCL for HEX. EPA disagrees with
the first comment and believes that taste
and odor problems do have an adverse
impact on consumers' confidence in the
drinking-water supply. However; the v •
Agency agrees with the second
commenter that additional work is
necessary to determine appropriate
levels for aesthetic effects. Accordingly,
the Agency may initiate in the future a
"National Task Force of Experts" to
review and assess the data, information
end opinions available with respect to
taste and odor problems in public water
supplies [as noted at 56 FR 3572, January
30.1991].
C. State Implementation
The Safe Drinking Water Act provides
that States may assume primary
implementation and enforcement
responsibilities. Fifty-five out of 57
jurisdictions have applied for and
received primary enforcement
responsibility (primacy) under the Act.
To implement the federal regulations for
drinking water contaminants. States
must adopt their own regulations which
are at least as stringent as the federal
regulations. States must also comply on
the requirements in 40 CFR 142.12 on
revising approved primacy programs.
This section of today's rule describes
the regulations and other procedures
and policies States must adopt or have
in place to implement the new
regulations.
To implement today's rule, States will
be required to adopt the following
regulatory requirements when they are
promulgated: § 141.23, Inorganic
Chemical Sampling and Analytical
Requirements; § 141.24, Organic
Chemicals Other Than Total
Trihalomathanes, Sampling and
Analytical Requirements: I 141.32,
Public Notice Requirements (Le.,
mandatory health effects language to be
included in public notification or
violations): § 141.61 (a) and (c).
Maximum Contaminant Levels for
Inorganic and Organic Chemicals.
In addition to adopting drinking water
regulations no less stringent than the
federal regulations listed above, EPA is
requiring that States adopt certain
requirements related to this regulation in
order to have their program revision
application approved by EPA. In various
respects, the NPDWRs provide
flexibility to the State with regard to
implementation of the monitoring
requirements under this rule. Because
Slate determinations regarding
vulnerability and monitoring frequency
will have a substantial impact with
implementation of this regulation.
today's rule requires States to submit, as
part of their State program submissions,
their policies and procedures in these
areas. This requirement will serve to
inform the regulated community of State
requirements and also help EPA in its
oversight'of State'programs. These'1'
requirements are discussed below under
the section on special primacy
requirements.
1. Special Stale Primacy Requirements
To ensure that the State program
includes all the elements necessary for
an effective and enforceable program,
the State's request for approval must
contain a plan to ensure that each
system monitor for the contaminants
listed in this rule by the end of each
compliance period.
In general, commenters supported the
proposed primacy requirements. Most of
the comments .were very similar to those
made on a previous proposed
rulemaking (May 22,1989. [54 FR
22135]). including the following: The
States do not have enough resources.
States should not have to report
vulnerability assessments to EPA, and
records should be kept for less than the
40-year requirement. These issues wera
all addressed in the January 1991 rule
[56 FR 3574].
Numerous comments were made
regarding requirements for sulfates. One
commenter was concerned about the
cost impacts on small systems trying to
achieve compliance with the proposed
MCL options of 400 mg/1 and 500 mg/1.
Under the SOW A, exemptions may be
granted by a State which would have
helped alleviate the cost impact of
compliance for sulfate. Another
commenter claimed that if variance*
and exemptions were allowed for
sulfate*, a significant portion of the
population would not be protected.
Under sections 1415 and 1416. before a
State may grant a variance or exemption
it must determine that the variance or
exemption will not result in an -
unreasonable risk to health. In addition.
a State must notify the public and
provide an opportunity for a public
hearing before a variance or exemption
is granted. Also, the State may require
that bottled water. POU devices, or POE
devices be used as a condition for
granting the variance or exemption. In
this manner, EPA believes that public
health would have been protected where
variances and exemptions were granted
for sulfate. To comply with today's rule.
States may update their monitoring plan
submitted under the January 1991 rule or
they may simply note in their
application that they will use the same
monitoring plan for this group of
contaminants.
In general States may use their
discretion to schedule when, within the
overall three-year compliance period.
each system will need to perform its
one-year-long initial monitoring. For-
example. States may decide to schedule
approximately one-third of the systems '"
for monitoring during each of the three
years, to provide for an even flow of
samples through State-certified
laboratories. States will be able to
establish their own criteria to schedule
the systems to monitor but the schedules
must be enforceable under State law.
If a State does not have primacy for
today's rule at the time the initial
compliance period begins (i.e.. January
1.1993). then EPA will be the primacy
agent. Because water systems must
monitor. EPA has established
procedures (|§ 141.23(k). 141.24(0(23).
and 141.24(h)(lB)J that require systems
to monitor at the time designated by the
State. If EPA implements today's
provisions because a State has not yet .
adopted the regulatory requirements in
today'! rule. EPA intends to use the
State's monitoring schedule to schedule
systems during each compliance period.
EPA believes this approach will reduce
confusion over the required monitoring
schedule that might occur upon the
eventual transfer of primacy from EPA
to the State.
2. State Recordkeeping Requirements
Some commenters characterized the
proposed recordkeepirig requirements as
burdensome and unwarranted. Similar
comments were received In reference to
the May 1989 proposed rules [54 FR
22135]. Similar comments were received
in reference to the May 1989 proposed
rules. In response to comments received
on that proposal, EPA modified the State
recordkeeping requirements to alleviate
the State burden. These changes are
explained in the January 1991 rule at 56
FR 3575. No additional changes have
been made in today's rule to the
recordkeeping requirements.
3. State Reporting Requirements
Generally, commenters characterized
the proposed State reporting
requirements as burdensome and
useless. Similar comments were
received in response to the May 1989
proposed regulations [54 FR 22136]. In
finalizing those regulations, EPA deleted
the proposed reporting requirements
(except for unregulated contaminants),
having determined that the core
reporting requirements of the Primacy-
Rule (December 20,1988 [54 FR 52126])
would be sufficient (»ee 56 FR 3576).
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Federal Register / Vol. 57, No. 138 / Friday. July 17. 1992 / Rules -and Regulations 31831
am*mmmmi^^mmmm^^**^t**—~l~'^~''^^^-^-*'~—~l^~'^~m~m^~~~lmmmm^*^~l~^^^~'^^~~l^~^mf
Today's mle similarly deletes the
proposed reporting requirements and
relies on the core reporting requirements
of the Primacy Rule.
- IV. Economic Analysis
In accordance with Executive Order
12291. the Environmental Protection-
Agency (EPA) has performed a
Regulatory Impact Analysis (RIA) which
is required for all "major" regulations. A
rule is considered "major" if it is
expected to cause:
(1) An annual effect on the economy
of $100 million or more:
(2) A major increase in costs or prices
for consumers, individual industries.
Federal. State, or local government
agencies, or geographic regions: or
(3) Significant adverse effects on
competition, employment, investment..
productivity, innovation, or on the
ability of the United States-based
enterprises to compete with foreign-
based enterprises in domestic or export
markets.
An economic analysis, titled
Economic Impact Analysis of Proposed
National Primary Drinking Water
Standards for 24 Inorganic and
Synthetic Organic Chemicals (Revised
Final) April 1990. was prepared (USEPA.
1990c). An addendum to the EIA. dated
May 15.1990. reclassified the rule as a
"major" rule {USEPA. 1990a). The EIA
indicated that national costs may
exceed $100 million if stringent options
were exercised. If stringent options were
not employed, then costs may not
exceed S100 million and the rule may be
classified as minor. Another addendum
to the EIA which revised the waste
disposal costs for sulfate was added to
the public docket on August 3,1990.
Today's final rule is accompanied by
a Regulatory Impact Analysis, titled the
Regulatory' Impact Analysis of Proposed
Phase V Synthetic Organic and
Inorganic Chemical Regulations
(USEPA. 1992dj. However, with the
deferral of the sulfate portion of the rule.
total costs are projected substantially
below those shown in the Regulatory
Impact Analysis. The Regulatory Impact
Analysis contains sulfate costs because
the document was completed before the
decision to defer sulfate was made.
In order to estimate the economic
- impacts these analyses used the
following data, where available, for
each of the 23 contaminants:
• Occurrence data, to determine the
number of systems violating MCLs;
V • Treatment and waste disposal cost
data and corresponding probabilities
that systems will select each of the
various treatment and disposal options,
to estimate the system level and
aggregate costs of achieving the
proposed MCLs: and
• .Monitoring costs, to estimate
aggregate costs of the monitoring
requirements.
Occurrence data adequate to estimate
the number of systems likely to violate
the MCLs are available- for 15:of these. 23.
contaminants. For the remaining 87
contaminants (endothall. diquat. di(2-
ethylhexyl) phthalate. glyphosate.
hexachlorobenzene.
hexachlorocyclopentadiene, 1.1.2-
trichloroethane. and 2.3.7.8-TCDD) cost
impacts could not be evaluated because
national .occurrence data are not
available. In response to public
comments, impacts of the rule are not
based on extrapolation from other SOC
contaminant occurrence, as in the
proposal.
The EIA supporting the proposed rule
estimated treatment costs for SOCs to
be Sll million per year and also
estimated the rule would affect 900
systems. Treatment costs for JOCs
varied depending upon the MCL used for
sulfate. Treatment costs for lOCs.
estimated in the EIA dated April 1990
and modified by the Addendum dated
August 3,1990. were projected to be $60
million and to affect 1.397 systems with
a sulfate MCL of 400 mg/1. An estimated
795 systems were projected to spend
about $28 million per year to achieve
compliance with a sulfate MCL of 500
mg/1. Monitoring costs for the proposed
rule, detailed in the Information
Collection Request for: Proposed
National Primary Drinking Water
Regulations For Phase V SOCs and
lOCs [USEPA. 1989a). were estimated to
be about S8 million per year. Thus, the
total annualized cost of the proposed
regulations were estimated to be $87
million per year with an MCL of 400 mg/
1. and $50 million per year at an MCL of
500 mg/1.
With the receipt of new data or
information, EPA made several changes
to the proposed economic analysis
which would have resulted in an overall
increase in the projected compliance
costs for the final rule if sulfate has not
been deferred. In addition, revised unit
cost and occurrence data were
incorporated into the final RIA. These
changes, and their corresponding effects
on the original cost estimates, are
described below.
A. Costs of the Final Rule
Treatment and waste disposal costs
associated with the final rule are
estimated based on occurrence
information available for 15 of 23
contaminants in thi« regulation. For the
other 8 contaminant* costs were not
estimated because adequate occurrence
data are not available. Monitoring and
State implementation cost estimates
include a consideration of all 23
contaminants.
Annualized total water treatment and
waste disposal costs are estimated at
$31 million per year (Table 22).
.•Monitoring costs-are'eatimated.to-be •••'.'" •
about $5 million per year. The annual
cost to State drinking water programs to
implement the final rule is estimated to
be $10 million. Thus, the total
annualized compliance cost to the
nation is estimated to be $46 million per
year. Further, given the uncertainty
associated with the inputs used to
estimate costs for the 16 contaminants
for which occurrence data are available
the total annual cost of this rule could
range from approximately $1 million to
$128 million. These cost estimates would
increase if the 8 contaminants for which
costs have not currently been estimated
were included.
Of the 23 contaminants covered by
this rulemaking. endrin is the only
contaminant regulated by an existing
National Primary Drinking Water
Regulation. The final MCL for endrin
promulgated today is greater than the
previously existing MCL. No systems
are projected to fail the final MCL for
endrin. Therefore, no incremental costs
of meeting the new MCL are anticipated.
However, costs associated with
regulating the other 22 contaminants in
this rulemaking do represent an
increased cost burden.
Table 23 shows the benefits of today's
rule. Most contaminants are being
regulated on the basis of non-
carcinogenic effects. Five contaminants
are being regulated on the basis of their
carcinogenicity. These are:
dichloromethane. benzo{a)pyrene, di(2-
ethylhexyl)phthalate,
hexachlorobenzene, and 2,3,7.8-TCDD.
Insufficient occurrence data were
available to estimate the number of
cancer cases avoided for these
contaminants. For the regulated
contaminants that are not carcinogens,
• the adverse effects associated with
exposure are discussed in both the
proposed rules and these final rules.
under the portions of the preamble that
describe derivation of the MCLGs. The
benefits of reduced exposure to these
contaminants relates to reducing the
•possibility that water consumers may
experience these adverse effects. For
example, antimony caused shortened
life spans, weight loss, increased
cholesterol levels, and reduced blood
glucose levels in test animals. The
possibility of any of these effects
occurring in exposed population* would
be reduced by reducing antimony
exposure to below the MCL.
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31832
Federal Register / VoL 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
TABLE 22.—SUMMARY OF COST ESTIMATES FOR FINAL RULE
! Best estimate
Cost m m&ioof of Dollars
1 256
:..! 238
• 14
! 30
I 5
!
1 46
i
Low estimate High estimate
30 795
2 925
<1 65
. . 1 • 128
N/A N/A
N/A N/A4
1 128
TABLE 23.—SUMMARY OF BENEFITS ESTIMATES FOR FINAL RULE
j Best estimate
Low-estimate
HK|h estimate
Ben«l,',j ($ Millions);
340
'0.0
j
4l
N/A 1
1.729
N/A
' Ol tho five carcinogenic contaminants regulated m this package, occurrence data are only available tot dichlorometnane. and these data indicate that MCL
eicvtdaoces ue unlikoly Tha estimate here does not mdude the other 4 carcinogens, nor does it reflect the (act that other contaminants m this package are group
"C" possible human carcinogens, but are not being regulated on the basis ol carcmogenicity.
B. Comparison to Proposed Rule
The costs and benefits of today's final
rule are compared to those estimated for
the proposal (Table 24). The differences
in the cost estimates are attributable to
a variety of changes in the rule and in
the available Input data used in the
analysis. Among the more important
changes are the following.
1. Monitoring Requirements
The Agency has developed a
standardized monitoring framework
(SMF) to address the issues of
complexity, coordination of monitoring
requirements between various
regulations, and synchronization of
monitoring schedules. The monitoring
requirements in today's rule are
somewhat different from those included
In the proposed rule, resulting in
reduction in annual national monitoring
costs of approximately $1 million, for all
contaminants, excluding sulfates. The
estimated monitoring cost of the final
rule is SS million annually. .
In this regulation. EPA is requiring
that initial monitoring begin in the first
compliance period after the
promulgation date for systems having
150 or more service connections. The
initial monitoring period for these
systems is from January 1,1993 through
December 31.1995. For systems with
fewer than 150 service connections,
initial monitoring is from January 1.1996
to December 31.1998. All systems must
monitor at the base monitoring
frequency unless a waiver is obtained.
Systems may decrease monitoring from
the base requirement upon receiving a
waiver from the state. In cases of
deteotion or noncompliance, EPA has
specified increased monitoring
frequencies.
2. Changes in MCLs
Several MCLs in the final rule have
changed from those that were proposed.
As discussed above, regulation of
sulfate has been deferred and no final
MCL has been set. The MCL for di(2-
ethylhexyljadipate is more stringent
based on a new health study which
resulted in a revised reference dose. The
MCL for 2,3,7.8-TCDD changed from 5 X
10"8 mg/Ho 3 X 10"*.mg/l because of
recently available analytic chemistry
data and the MCL for di(2-
ethylhexyl)phthalate changed from 0.004
mg/1 to 0.006 mg/1 based on
.reevaluation of the chemistry data. The
MCL for beryllium was revised from
0.001 mg/1 to 0.004 mg/1 based on public
comments and because there are
inadequate data to justify the more
stringent proposal. The MCL for 1,2,4-
trichlorobenzene was revised because
EPA agrees with public comments that
the oral RfD should not be based on an
inhalation study, particularly because
insufficient pharmacokinetic data are
available for route-to-route
extrapolation, changing from 0.009 mg/1
to 0.07 mg/1. The MCL for antimony was
revised based on a reassessment of the
relative source contribution, and
simazine was revised based on new
health effects data which allowed
elimination of an uncertainty factor
included to account for a data gap.
TABLE 24.—COMPARISON OF COSTS FOR PROPOSED AND FINAL RULES
[Dollar Figures in Minions]
-
Contaminants
Suttatt (400 fna/fl
Swf *!t (500 mg") . , . ,.. -,,-, „-.,,-,,,., — -
K5Gt (ExduAofl SuHito)
SOCi ffortrtog pesbottw and VQCi
MoottCOAQ COStS .....j _! _.!..,.„!..._....!. TTT ....-». ...
Prop
)
System affected
1 087._ ......
485
310
900
2.297
78.703... —..
54 States and
Teoilooes.
asod
ToUlcost
(annualized) S
million*
67
30
3
1 1 ;.. .
£1
6 _
Not esfcmated.....
Fm
Systems affected
N/A
N/A . .,
207
49 ;_.„ . .
258
,78.703 .._»_
54 States and
Twrrtories.
>al
Total cost
(armuakzed) S
millions
N/A
N/A
30
1
31
5
10
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Federal Register / VoL 57, No. 138 / Frida3f, July 17, 1992 / Rules and Regulations
31833
TABLE 24.—COMPARISON OF COSTS FOP PROPOSED AND FINAL RULES—Continued
[Doltv Figures in Millions}
Contaminants
Nation* wfMtato eo« (SMfY'V ; '. ,, , , ,
--
Prop
Systems •Heeled
osed
Total cost
(annuateed) J
millions
87
Fir
Systems affected
ul
Total cost
(anouataed) S
ml Ions
AM
Note: Totals may not tally due to independent rounding. MCLs of 400 mg/l and 500 mg/l were proposed for sutfate.
3. Changes in Occurrence Data
Some occurrence data used in the
final RIA have been changed. A re-
evaluation of the National Inorganics
.and Radionuclides Survey data resulted
in revised antimony occurrence
estimates and estimates of systems
exceeding the MCL The number of
systems estimated to exceed the
beryllium MCL changed as a result of
MCL changes. Further review of the EPA
occurrence document resulted in a
revised occurrence estimate for
dichloromethane. For di{2-
ethylhexyl)adipate, the occurrence
estimate has been changed to reflect a
re-evaluation of available occurrence
data and a change in the MCL For 8
contaminants (endothall, diquat, di(2-
ethylhexyl) phthalate, .glyphosate.
hexachlorobenzene.
hexachlorocyclopentadiene, 1,1.2-
trichloroethane, and 2,3.7,8-TCDD)
adequate data are not available. In the
EIA accompanying the proposed rule.
approximately 82 systems were
assumed to fail the MCL for each
contaminant and to be required to
install treatment equipment. EPA
currently believes that there are
inadequate data with which to estimate
number of systems exceeding the MCL*
for these contaminants and that an
estimate of 82 systems for each
contaminant is potentially inaccurate.
While EPA is unable to estimate the
number of systems potentially
exceeding the MCL it in recognized that
an unknown number of systems may be
required to install treatment for each
contaminant.
4. Changes in Unit Treatment Cost
Estimates
The differences between unit
treatment costs in today's rule and in
the proposed rule are due to differences
in the treatment alternatives included,
the assumed percentage of production
flow treated, and the discount rate used
in annualizing capital costs. Capital
costs in the proposed rule were
annualized over 20 yean at a 10%
interest rate to derive annual costs. The
3% interest rate used in today's final rule
was selected in order to make the costs
of the Phase V regulations comparable
to cost estimates prepared for earlier
rules.
C, Cost to Systems
Table 25 indicates that relatively few
water systems and consumers will be
affected by the regulations. However,
costs will vary depending upon the
specific chemical contaminant and the
size of the public water system.
Systems serving 500 or less people
will incur higher per household costs
because they do not benefit from
engineering economies of scale.
Households served by these systems
would have to pay significantly more.
should their system have contamination
greater than the MCL.
TABLE 25.—INCREASED COST OF COMPLIANCE IN SELECTED SYSTEM S'IZE CATEGORIES
System Scze ! 25-100
Contaminant
Antimony
Nickel
Dicnioromettv
ane
Dinoseb
Annual
Cost per
Household
13.651
1,747
353
984
Cost per
System
$49.500
25.000
4.400
12.500
Number
of
Systems
es
4
18
4
101-600
Annual
Cost per
Household
$1.721
717
138
343
Cost per
System
$102.800
43.300
7.300
20,000
Number
of
Systttms
57
3
11
3
3.301-10.000
Annual
Cost per
Household
$274
0
12
0
Cost per
System .
$521.000
0
2S.OOO
0
Number
of
Systems
10
0
2
0
25.001-50.000
Annual
Cost per
Household
$137
0
0
0
Cost per
System .
$1.935,000
0
0
0
Number
of
Systems
2
0
0
0
Note: For systems serving over 1,000.000 people, no MCt excoedance or cost is estimated.
D. Cost to State Programs
In 1988, EPA and the Association of
State Drinking Water Administrators
(ASDWA) conducted a survey of State
primacy program resource needs for
implementing the 1988 SDWA
amendments. State implementation
costs for the Phase V rule were not
included in the ASDWA survey. State
implementation costs of previously
regulated Phase II inorganic and
synthetic organic chemicals are
estimated to be $21 million during the
initial phase. An additional $17 million
is estimated to be required for States to
annually conduct enforcement actions,
assist in the expansion of laboratory
capabilities, and manage compliance
schedules. Laboratory expansion
undertaken to implement Phase n
regulations will largely satisfy the
monitoring needs of this rule. Total State
implementation coqts are anticipated to
be in the range of $7 million to $12
million. A gross point estimate of $10
million pet year has been selected for
today'* final rule.'
V. Other Requirements
A. Regulatory Flexibility Analysis
The Regulatory Flexibility Act
requires EPA to consider the effect of
regulations on small entities [5 U.S.C.
602 et seq.]. If there is a significant
economic effect on a substantial number
of small entities, the Agency must
prepare a Regulatory Flexibility
Analysis (RFA) describing significant
alternatives that would minimize the
impact The Agency had determined that
the proposed rule, if promulgated would
not have a significant economic impact
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31834 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
on a substantial number of small
entities.
According to EPA guidelines for
conducting RFA assessments, less than
20 percent of a regulated population is
not considered a substantial number.
The RFA for the final rule indicates that
of 77.910 community and non-transient
non-community water supplies serving"
50.000 or fewer people, about 253 (<1
percent) are estimated to exceed the
final MCLs promulgated in today's rule.
Therefore, today's rule does not affect a
substantial number of such small
systems.
Compliance costs for the 253 systems
serving 50.000 or fewer people required
to install treatment are about S31 million
per year for capital and operational
maintenance. This is less than one
percent of the total national operating
expense for such systems. Therefore, at
a national aggregate level, the Phase V
rule would not have a significant impact
on small systems. This finding does not
change if the costs of monitoring to
these systems, S6 million per year, are
included.
"The Agency's determination of no
significant economic impact on a
substantial number of small systems
would remain unchanged under a more
stringent definition of small systems.
Defining systems serving 3.300 or fewer
people as small, today's rule would
affect 235 of the 65.766 public systems in
this size category. This represents less
than one percent of such systems. Costs
would increase S16 million, or
approximately one percent of the total
operating expense for all systems in this
category. The inclusion of monitoring
costs of less than S4 million for such
systems does not alter this finding.
EPA's determination of no significant
economic impact on a substantial
number of small systems would likely
also remain the same if occurrence data
on the eight contaminants not currently
included in this analysis became
available. While it is not possible to
estimate the number of systems
exceeding the MCLS for these
contaminants the number is potentially
small as these contaminants have rarely
been found in drinking*water.
Although there will not be a
significant economic impact on a
substantial number of small systems on
the whole, a small number of individual
systems may find their costs increasing
sharply, depending on the specific
contaminant in their water. For
example, it can be seen from Table 25
that a system serving 25-100 people with
antimony-contaminated water is
expected to incur additional annual
costs of $49,500. EPA is concerned about
such systems. Under the Safe Drinking
Water Act small systems may obtain an
exemption for national primary drinking
water regulation requirements if they
can demonstrate that the granting of the
exemption would not result in an
unreasonable risk to health, among
other conditions. Other aspects of the
regulatory scheme that serve to reduce
impacts on small systems are described
in the proposal (55 FR 30436) and earlier
in this notice.
B. Paperwork Reduction Act
The information collection
requirements in this rule have been
submitted for approval to the Office of
Management and Budget (OMB) under
the Paperwork Reduction Act [44 U.S.C.
3501 et seq.]. These requirements are not
effective until OMB approves them and
a technical amendment to that effect is
published in the Federal Register.
Public reporting burden for this
collection of information is estimated to
average 0.6 hours per response for
public water systems and 13.6 hours for
States to compile each response. These
estimates include time for reviewing
instructions, searching existing data
sources, gathering the information
needed, and completing and reviewing
the collection of information as well as
start-up activities such as staff training.
Comments regarding the burden
estimate of any other aspect of this
collection of information, including
suggestions for reducing this burden.
should be sent to Chief. Information
Policy Branch. PM-223Y. U.S.
Environmental Protection Agency, 401 M
Street, SW.. Washington. DC 20460; and
to the Office of Information and
Regulatory Affairs, Office of
Management and Budget, Washington.
DC 20503, marked "Attention: Desk
•Officer for EPA."
C. Federalism Review
Executive Order 12612 requires all
federal agencies to consider legislative
and regulatory proposals and other
major policy actions to determine if they
have substantial effects on federalism
goals and principles as-set forth in the
Executive Order. According to EPA's
Guidelines for Implementing Executive
Order 12612: Federalism, "[i]f an EPA
action is mandated or the necessary
means to carry it out are implied by
statute, then no further, federalism
assessment is required." Twenty-two of
the 23 contaminants regulated today are
included in the list of 83 contaminants
for which EPA is required to promulgate
National Primary Drinking Water
Standards. Therefore, a federalism
assessment is not required to support
this rule for these listed contaminants.
For hexachlorobenzene, which is not
on the list of 83 contaminants, a
federalism assessment is not required
because today's regulation will not have
a substantial direct effect on States, the
relationship between the Federal
Government and the States or on the
distribution of power, and •.
responsibilities among the various levels
of government.
VI. References
40 CFR Part 136. Appendix A
40 CFR Part 136, Appendix B
Adams. J.Q.. and R.M. Clark. 1989. Cost
Estimates for CAC Treatment Systems.
JAWWA 1:35-42. [Adams and Clark. 1989|
Alben. K. 1980. Coaltar Coatings of Storage
Tanks. A Source of Contamination of the
Potable Water Supply. Environ. Sci.
Technol. 14:468-470. [Alben. 1980|
Ambrose, A.M., P.S. Larson. J.R. Borzelleca
and G.R. Hennigar. jr. 1976. Long-term
Toxicologic Assessment of Nickel in Rats
and Dogs. J. Food Sci. Technol. 13:181-187.
[Ambrose et al.. 1976]
American Biogenics Corp. 1986. Ninety day
gavage study in albino rats using nickel.
Draft Final Report Submitted to Research
Triangle Institute.'P.O. Box 12194. Research
Triangle Park. NC 27709. [American
Biogenics. 1986)
Amoore, John E and Earl Hautala. Odor as
an Aid to Chemical Safety: Odor
Thresholds Compared with Threshold Limit
Values and Volatilities for 214 Industrial
Chemicals in Air and Water Dilution.
Journal of Applied Toxicology. Vol. 3. No.
6.1983.19 pp. [Amoore and Hautala. 1983)
Bababunmi et al.. 1978. Toxicology and
Applied Pharmacology 45:319-370.
(Bababunmi et al., 1978)
Basu. O.K., J. Saxena. F.W. Stoss. ).
Santodonato. M.W. Neal and F.C. Kopfler.
1987. Comparison of Drinking Water
Mutagenicity with Leaching of Polycyclic
Aromatic Hydrocarbons from Water
Distribution Pipes. Chemsphere 16. No. 10-
12. p. 2595. [Basu et al.. 1987)
Biodynamics. Inc. 1981 a. A three-generation
reproduction study in rats with glyphosate.
Project No. 77-2063 for Monsanto Co.. St.
Louis, MO. EPA Accession No. 245909 and
247793. (CBI) [Biodynamics. 1981a)
Biodynamics, Inc. 1981 b. Lifetime Feeding
Study of Glyphosate (Roundup Technical).
Project No. 77-2062 for Monsanto Co.. St.
Louis. MO. EPA Accession Nos. 246617 and
246621. (CBI) [Biodynamics, 198lb|
Brown, D. 1961. Dmoseb: A 100-Week Oral
(Dietary) Toxicity and Carcinogenicity
Study in the Mouse. H'azleton Laboratories
Europe. Ltd. Prepared for Dow Chemicals
• Pacific. Ltd.. Hong Kong-. MRID 00152764.
[Brown. 1981]
Chemical Engineering ft News. 1977. Method
Rids Agent Orange of TCDD
Contamination. 55{11):Z5. [Chemical Eng..
1977J
Chien, L.. H. Robertson and J.W. Gerrard.
1968. Infantile Gastroenteritis Due to Water
with High Sulfate Content. Can. Med.
ABSOC. ]. 99:102-104. (Chien et al.. 1968]
-------
Co^ey. ]. el al 1985, Reference Doses (RfDs)
far-.OTa\Exposure. U.S. EPA. Study by
Huntington Research Centre. England.
(Colley et al.. 1985]
Congressional Record. 1974. House of
Representatives 93-1185. at 18. The 93rd
Congress. Second Session. 13. Microfilm
=H503-28.
Congressional Record. 1974. House of
Representatives 1185.93rd. Congress.
• Second Session—Microfilm »H503-2a.'
Congressional Record. 1986. Vol. 132. 99th
Congress. Second Session. No. 69. May 21.
1986. p. S6287. Statement by.Senator
Durenberger. [132 Cong. Rec.\
Congressional Record. 1985. Senate Report
No. 56. 99th Congress. First Session at 6.
Microfilm =5323-10.
Cunningham. W.C. and W.B. Stroube. 1987.
Application of an Instrumental Neutron
Activation Analysis Procedure to Analysis
of Food. Division of Contaminants
. Chemistry. Food and Drug Administration.
Washington. DC. In: The Science of the
Total Environment. Vol. 63. pp. 29-13.
(Cunningham and Strobe. 1987]
Epstein. D. L.. ei al. 1991. Two generation .
Reproductive Toxicology Study In Rats
EPA Guidelines No. 63-4. Research Dept..
Pharmaceuticals Division. ClBA-Ceigy
Corp. Study No. 882095. Vol. 1. Feb. 12.
1991. MRID =418036-01. [Epstein et al..
1991)
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-------
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Science & Technology, Office of Water.
January 1992. [USEPA. 1992g]
U.S. EPA. 1992h. Drinking Water Criteria
Document for Cyanide. Health & Ecological
Criteria Division. Office of Science &
Technology, Office of Water. January 1992.
[USEPA. 1992hJ
Watanabe, P.G.. R.J. Kociba. R.E. Hefner. Jr.,
H.O. Yake! and B.K.J. Leong. 1978.
Subchronic Toxicity Studies of 1.2,4-
Trichlorobenzene in Experimental Animal*.
Toxicol. Appl. Pharmacol. 45(l):332-333.
[Watanabe et al.. 1978]
White. K.L, V.M. Sanders, D.W.. Barnes,
G.M. Shoup and A.E. Muiuon. 1985.
Toxicology of 1,1.2-Trichloroethane in the
Mouse. Drug Chem. Toxicol. 8:333-355.
[White et al.. 1985]
World Health Organization. 1984. Guideline*
for Drinking-Water Quality. Vol. 2. Health
Criteria and Other Supporting Information.
Geneva, pp. 290-292. [WHO. 1984]
ZoJdak. J.J. 1978. Anarysi* of Drinking Water
for Tree* Level Quantities of Organic
Pollutant*. Thesi*. Miami University.
Oxford. OH. Cited in MAS. 1982. [Zoldak,
1S78J
-------
31838 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
List of Subjects In 40 CFR Parts 141 and
142.
Administrative practice and
procedure. Chemicals. Indians-lands.
Intergovernmental relations. Radiation
protection. Reporting. reeordkeeping
requirements. Water supply.
Dated: May 18,1992.-
F. Henry Habicht II.
Administrator.
For the reasons set forth in the
preamble, chapter I of title 40 of the
Code of Federal Regulations is amended
as follows:
PART 141—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
1. The authority citation for part 141
continues to read as follows:
Authority: 42 U.S.C. 300f. 300g-l. 300g-2.
300g-3.3008-4.300g-5.300g-6.300J-4 and
300J-9.
2. Section 141.2 is amended by
revising.the definition for "Initial
compliance period" to read as follows:
§ 141.2 Definition*.
• « « * •
Initial compliance period means the
first full three-year compliance period
which begins at least 18 months after
promulgation, except for contaminants
listed at 141.61{a) (19}-{21). (c)(19)-{33).
and 141.62(b) (11H16). initial
compliance period means the first full
three-year compliance period after
promulgation for systems with 150 or
more service connections (January 1993-
December 1995), and first full three-year
compliance period after the effective
date of the regulation (January 1996-
December 1998) for systems having
fewer than 150 service connections.
*r * * * *
3. Section 141.6 is amended by adding
paragraph (h), to read as follows:-
5141.6 Effectlvt Date.
• ' • * ,• *
(h) Regulations for the analytic
methods listed at . 141.23(k)(4) for
measuring antimony, beryllium, cyanide.
nickel, and thallium are effective August
17.1992. Regulations for the analytic
methods listed at 5 141(f)(16) for
dichloromethane, 1.2,4-trichlorobenzene,
and 1,1.2-trichloroethane are effective
August 17,1992. Regulations for the
analytic methods listed at § 141.24(h)(12)
for measuring dalapon. dinoseb, diquat.
endothall, endrin. glyphosate. oxamyl,
picloram. simazine. benzo(a)pyrene,
di(2-ethylhexyl)adipate. di(2-'
ethylhexyljphthalate,
hexachlorobenzene.
hexachlorocyclopentadiene, and 2.3,7,8-
TCDD are effective August 17,1992. The
revision to 5 141.12(a) promulgated on
July 17.1992 is effective on August 17.
1992.
4. Section 141.12 is amended by
removing and reserving paragraph (a) in
the table to read as follows:
S 141.12 Maximum contaminant leveta for
organic chemical*.
(a) [Reserved)
• * * • •
5. Section 141.23, which will be
effective, is amended by revising the
introductory text to paragraph (a)(4). by
revising the introductory text to a
(a)(4)(i), (a)(4)(i) table, by adding
paragraph (a)(4)(iii). by. revising-
paragraph (c) introductory text. (c)(l).
and (i)(l). by redesignating (k)(5) as
(k)(6) and revising it, redesignating (k)(4)
as (k)(5) and revising it, and by adding a
new (k)(4) to read as follows:
§ 141.23 Inorganic chemical sampling and
analytical requirements.
• •, • • _ •
(a) *" * .'
(4) The State may reduce the total
number of samples which must be
analyzed by allowing the use of
compositing. Composite samples from a
maximum of five samples are allowed.
provided that the detection limit of the
method used for analysis is less than
one-fifth of the MCL. Compositing of
samples must be done in the laboratory.
(i) If the concentration in the •
composite sample is-greater than or
equal to one-fifth of the MCL of any
inorganic chemical, then a follow-up
sample must be taken within 14 days at
each sampling point included in the
composite. These samples must be
analyzed for the contaminants which
exceeded one-fifth of the MCL in the
composite sample. Detection limits for
each analytical method and MCLs for
each inorganic contaminant are the
following:
DETECTION LIMITS FOR INORGANIC CONTAMINANTS
Conlirrur.im
A3&0S10S _«_ «« ....... .,
Banum , . _«.*<, »»* ,<_._..,
8Mass Spectromotry . . .
Atomic Absorption* (umac* tecfirwQue «.:
Atomic Absorptxyv <1*r8C1 •spraixxi '......
Inductively Goopted Plasma . .
Atomic Absorption; Furnace ,...,„..,...,„ '.... .
xi „ _ _ _ _ _
Inductively Coupted Plasma ' . ___ _. .. _._ _
ICP-Mass Sp-ctrometry . .. _ _
Atomic Absorption; furnace technique
Inductively Coupled Plasma - - „
Atomic Absorption* furnace technique . .. - - - -
Inductively Coupled Plasma.... ..„_ /. .+ _ _ _ ..
Distillation. Spectropnotomctric 4
Distillation Automated Spectrophotometric * - « _
Distillation, S«tectiv« Electrode *
Destination, Amentbte. Spectroptiotomfllnc * .. , . T „
Manual Cold Vapor Technique ___._._. _„_. ......._„__ __.._„„__ .___.._
Aual"Kl CoW Vapof Technique ........ ..._ _
Atomic Absorption; Furnace . .. _ _.. .«.._ . . _ j. . . ....
Inductively Coupted Plasma *. -•• -• ... _.'._'._
ICP-Mtss Spectromelry. -.. - _ •.„ _
Detection
limit (mg/l)
0003
0.0008'
0.0004
0.001
0.01 MFL
0.002
0.1
0.002
(0.001) '
0.0002
0.00002"
0.0003
0.0003
0.0001
0.001 '
0.001
0.007
(0.001) '
0.02
0.005
005
0.02
0.0002
0.0002
0.001
00006*
0.005
0.0005
-------
DETECTION LJMJTS FOR INORGANIC CONTAMINANTS—Continued
Contaminant
MCL
(mg/l)
Methodology
Detection
limit (mg.'i)
Nitrate,
10 (as N)..i Manual Cadmium Reduction
I Automated Hydrazine' Reduction..
| Automated Cadmium Reduction...
i Ion Selective Electrode
.; 0 01
0.01
...: O.OS
NHtme 1 (as I
Ion Crwomatograpny..
!
Selenium
Thallium
j 0.05
i Automated Cadmium Reduction...
; Manual Cadmium Reduction .........
: Ion Chr'omatOQfaphy ....... . ..............
Atomic Absorption: lumace
Atomic Absorption; gaseous hydnde...
! 0.002 Atomic Absorption: Furnace
CP-Mass Spectrometry...
...j 0.01 ,
..... 0.01
..... 0.05
....; o.oi
.... 0.004
..... 0.002 •
....) 0.002
....I 0.001
I 0.0007 «
.... 0.0003
1 Us:r>g concentration technique in Appendix A to EPA Method 200.7.
«MFL = miUion fibers per liter > 10 ^m. — •
' Using a 2X preconcentration step as noted m Method 200.7. Lower MDLs may be achieved when using • 4X preconcentration.
• Screening metnod for total cyanides.
' Measures "free" cyanides.
" Lower MDLs are reported using stabilized temperature graphite lumace atomic absorption.
(iii) If duplicates of the original
sample taken from each sampling point
used in the composite are available, the
system may use these instead of
resampling. The duplicates must be
analyzed and the results reported to the
State within 14 days of collection.
« • * • •
(c) The frequency of monitoring
conducted to determine compliance with
the maximum contaminant levels in
1141.62 for antimony, barium, beryllium.
cadmium, chromium, cyanide, fluoride,
mercury, nickel, selenium and thallium
shall be as follows:
(1) Groundwater systems shall take
one sample at each sampling point once
every three years. Surface water
systems {or combined surface/ground)
shall take one sample annually at each
sampling point.
• • • • •
(i) * ' *
(1) For systems which are conducting
monitoring at a frequency greater than
annual, compliance with the maximum
contaminant levels for antimony.
asbestos, barium, beryllium, cadmium.
chromium, cyanide, fluoride, mercury,
nickel, selenium and thallium is
determined by a running annual average
at any sampling point. If the average at
any sampling point is greater than the
'MCL. then the system is out of
compliance. If any one sample would
cause the annual average to be
exceeded, then the system is our of
compliance immediately. Any sample
below the method detection limit shall
be calculated at zero for the purpose of
determining the annual average.
• • • • • •
(k) Inorganic analysis
(4) Analysis for the listed inorganic
contaminants shall be-conducted using
the following methods:
Contaminant
•
Beryfhum
Cyanide
Mercury _
Nickel
Vstrat«._— . — —
•Methodogy !
Atomic Absorption; Fumac* *
ICP-Mass Spectrometry • .
Hydnde-Atorrac Absorption * ...
AtoTvc Absorption: Furrmc**..-
Atorruc Absorption; Direct*..-
Inductively Coupled Plasma * _ ".
Atomic Absorption; Furnace *
Atomic Absorption' Platform*...
ICP-Mass Spectrometry *
Inductively Coupt^d Plasma *,, ,L ...
DtstiHabon Spec .. -
Distillation. Setectiv* Electrode _ _.
Distillation, Amenable. Spec.
Manual CokJ Vapor Technique • - =
Automated Coid Vapor Technique * .. -
Atomic Absorption* Fumaot * ......
tntKjcttvqfy Coupteft P1»iiTa * , , , ,
ICP-M*s» Sp8CTnxn»try • , ' , ,,. ,,
Manual Cadmium Reduction
Aufm>t1^d Hy9 FWrJurtoo
Automated C*dmium Reduction .-
EPA ••*•»!
1 2CM.2
1 220.9
•200.8
12 EPA
i 20S.2
•208.1
'200.7
1 210.2
•2009
1 200.7
» -200.8
1 213.2
•200.7
'218.2
1 200.7
1 335.2
1 335.3
'335.1
1 245.1
1 245.2
'249.2
1 249 1
•200.7
•200.8
•353.3
' 353.1
'353.2
ASTM»
D-3697-87
D-3645-848
D-2036-69A
D-2O36-69A
D-2O36-898
D3223-66
-
D3867-90
03867-90
SM* i
3113 *
3113B
3111D
3120
3113
3120
31138
31138
3120
4500-CN-O
450O-CH-E
4500-CN-F
4500-CN-G
31128
3113
311 IB
3120' ' "
4500-NOr-e
4500-NQr-F
USGS«
'
(330085
Other
-
-------
31840
Federal Register / Vok 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
ComarrnMnt
, — — —
Thai!wr> ...-,.<«>—.—
• "Memods ol <
| Methodogy
I
t
,.„., Spectophometnc
Automated Cadmium Reduction...
ion Chromatography __
... Hydrate-Atomic Absorption • .'.'. —
, Atomic Absorption: Furnace
, !CP-Mass Spectrometry •
memicaJ Analysis ol Water and Waste
I
i
!
i
!
.._ i
j
EPA •• l "
' ' 300.0
'354.1
1 353.2
' 353.3
' ' 300.0.
' 270.2
' 279.2
5 200,9
•200.8
ASTM»
03867-90
03867-90
03859-88
|
SM» j USGS« ; Other
4500-NOj-F
4500-NOj-E
3113B
3113
WeWWG/
5880'
B-1011 •
B-1011"
i
1
s." EPA Environmental Momtonng Systems Laboratory. Cincinnati. OH 45263 March 1883. EPA-*OU/«-
^
-
,s
vapor
digestion
U^?-%aty^J Memod For Determinate of Asbestos Fibers in Water." EPA-600/4-83-043. September 1983. U.S. EPA Environmental Research Laboratory.
Atrwu. GA 30613,
ait?i »w samples.
Chemistry Branch. Environmental Momtonng Systems
(5) Sample collection for antimony,
asbestos, barium, beryllium, cadmium.
chromium, cyanide, fluoride, mercury.
nickel, nitrate, nitrite, selenium, and
thallium under this section shall be
conducted using the sample
preservation, container, and maximum
holding time procedures specified in the
table below:
Contaminant
Preservative '
Container * I Time :
j Cone HNO, to pH <2 j P or G ! 6 months.
Antimony,™..™..—. •• I cool 4'C - • P or G j
AsaestOS... ••• " ; j cone HNO, to pH <2. j P or G 6 months.
Banum,,..., - - Cone HNO, to pH <2 j P or G , 6 months.
BeryKtum... „ ~~ -...-•- - - Cone HNO, to pH <2,. P or G 6 months.
Cadmium...,,,™....... - .. Cone HNO, to pH <2 i P or G : 6 months.
Ctvorroum.™.™.. • | cool. 4'C. NAOH to pH > 12. ! P or G i 14 days.
Cyanide..™~... ••-- - - I None - P or G : 1 month.
Ftuonde - - '"!""! Cone "HNO, to pH <2 P or G j 28 days
Mercury,,...., . '• j 00^ HNO, to pH <2 P or G 6 months.
Niuats
Non-cWonnated, ~ ~
Nilrrte, — -
Stfoowm „„.........,„......,...,.,
ThaHtum «,.,..._,«—-.«...— „.....
Cool. 4'C
Cone H,SO, to pH <2
Cooc HNOj 10 pH <2 ----------
Cone HNO, to pH <2 ..........
P or G ................. i 28 days.
P or G
PorG
P or G
P or G
I
14 days.
48 hours.
6 months.
6 months.
restrictions, samp* may be .nuially preserved by icing and. knmediatety .Noping it to the laboratory. Upon recent
cone HNO, to pH < 2 and held lor 16 hours before analysis.
« Se« m«tnod{s) for the mlormatxxi (or preservatxjrt
(6) Analysis under this section shall
only be conducted by laboratories that
have been certified by EPA or the State.
Laboratories may conduct sample
analysis under provisional certification
until January 1.1996. To receive
certification to conduct analyses for
antimony, asbestos, barium, beryllium.
cadmium, chromium, cyanide, fluoride.
mercury, nickel, nitrate, nitrite and
selenium and thallium, the laboratory
must:''
(i) Analyze Performance Evaluation
samples which include those substances
provided by EPA Environmental
Monitoring Systems Laboratory or
equivalent samples prpvided by the
State.
' (ii) Achieve quantitative results on the
" analyses that are within the.following
acceptance limits:
Contaminant
Antimony —..—.•
Asbesto*
Barium
BeryMum'.—
Cadmium
Ctrormum—
Cyanide
Mercury —
Nickel..-.
Nitrate—
Nitrite —
Acceptance limit
6*30 at > 0.006 mg/1
2 standard deviations
based on study
statistics.
±15% at >0.15mg/1
±15% at iO.OOl mg/1
±20% at ^0.002 mg/1
±15% at >0.01 mg/1
±25% at >0.1 mg/1
±10% at 21 to 10 mg/l
±30% at > 0.0005 mg/1
±15% at >0.01 mg/1
±10% at >0.4 mg/1
±15% at >0.4mg/1
-------
Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations 31&1
Contaminant
Acceptance limit
Selenium.
Thallium...
±20«i at >0.01 mg/1
= 30S at > 0.002 mg/1
6. Section 141.24 is amended by
revising paragraph (f) introductory text. •
paragraphs (0 introductory text,
paragraphs (0(4). (f)(S). (0(7). and (0(10).
(0(11). introductory text, (0(12), the
introductory texts of (f) (14), (0(15) and
(0(16) revising (0 (17) and (18), (h)(10).
(h)(19)(i)(B), and adding paragraphs
.(h)(12)(ixHxiv) to read as follows:
§ 141.24 Organic chemicals other than
total trialomethanes, sampling and
analytical requirements. -
• • • * *
(0 Beginning with the initial
compliance period, analysis of the
contaminants listed in § 141.61(a) (1)
through (21) for the purpose of
determining compliance with the
maximum contaminant level shall be
conducted as follows:
• * * • *
(4) Each community and non-transient
non-community water system shall take
four consecutive quarterly samples for
each contaminant listed in § 141.61(a)
(2) through 21 during each compliance
period, beginning in the initial
compliance period.
(5) If the initial monitoring for
contaminants listed in § 141.61(a) (1)
through (8) and the monitoring for the
contaminants listed in § 141.61(a) (9)
through (21) as allowed in paragraph
.(0(18) has been completed by December
31, 1992, and the system did not detect
any contaminant listed in § 141.61(a) (1)
through (21), then each ground and
surface water system shall take one
sample annually beginning with the
initial compliance period.
• * • • *
(7) Each community and non-transient
ground water system which does riot
detect a contaminant listed in
§ 141.61(a) (1) through (21) may apply to
the State for a waiver from the
requirements of paragraphs (0(5) and
(0(6) of this section after completing the
initial monitoring. (For purposes. of this
section, detection is defined as >0.0905
mg/1.) A waiver shall be effective for no
more than six years (two compliance
periods). States may also issue waivers
"to small systems for the initial round of
monitoring for 1.2,4-trichlorobenzene.
• • • • *
(10) Each community and non-
transient surface water system which
does not detect a contaminant listed in
§ 141.61(a) (1) through (21) may apply to
the State for a waiver from the
requirements of (0(5) of this section
after completing the initial monitoring.
Composite samples from a maximum of
five sampling points are allowed.
provided that the detection limit of the
method used for analysis is less than
one-fifth of. the MCL. Systems meeting.
this criterion must be determined by the
State to be non-vulnerable based on a
vulnerability assessment during each
compliance period. Each system
receiving a waiver shall sample at the
frequency specified by the State (if any).
(11) If a contaminant listed in
§ 141.61(a) (2) through (21) is detected at
a level exceeding 0.0005 mg/1 in any
sample, then:
• « • a 4 • *
(12) Systems which violate the
requirements of § 141.(>l(a) (1) through
(21), as determined by paragraph (0(15)
of this section, must monitor quarterly.
After a minimum of four consecutive
quarterly samples which show the
system is in compliance as specified in
paragraph (0(15) of this section the
system and the State determines that
the system is reliably and consistently
below the maximum contaminant level,
the system may monitor at the
frequency and times specified in
paragraph (0(H)(iii) of this section.
* • i * * «
(14) The State may reduce the total
number of samples a system must
analyze by allowing the use of
compositing. Composite samples from a
maximum of five sampling points are
allowed, provided that the detection
limit of the method used for analysis is
less than one-fifth of the MCL.
Compositing of samples must be done in
the laboratory and analyzed within 14
days of sample collection.
• * • * *
(15) Compliance with § 141.61(a) (1)
through (21) shall be determined based
on the analytical results obtained at
each sampling point.
• • • « •
(16) Analysis for the contaminants
listed in § 141.61{a) (1) through (21) shall
be conducted using .the: following EPA
methods or their equivalent as approved
by EPA. These methods are contained in
Methods for the Determination of
Organic Compounds in Drinking Water,
EPA/600/4-S8/039. ami are available
from the National Technical Information
Service (NTIS) NTlS PB91-231460 and
PB91-146027. U.S. Department of
Commerce, 5285 Port Royal Road.
Springfield. Virginia 22161. The toll-free
number is 800-333-4700.
* * • « •
(17) Analysis under this section shall
only be conducted by laboratories that
are certified by EPA or the State
according to the following conditions
(laboratories may conduct sample
analysis under provisional certification
until January 1.1996):
(i) To receive certification to conduct
analyses for the contaminants in
§ 14I.81(a) (2) through (21) the
laboratory must
(A) Analyze Performance Evaluation
samples which include these substances
provided by EPA Environmental
Monitoring Systems Laboratory or
equivalent samples provided by the
State.
(B) Achieve the quantitative
acceptance limits under paragraphs
(0(17)(i) (C) and (D) of this section for at
least 80 percent of the regulated organic
chemicals listed in 8 141.61 (a) (2)
through (21).
(C) Achieve quantitative results on
the analyses performed, under paragraph
(0(17)(i)(A) of this section that are
within ±20% of the actual amount of the
substances in the Performance
Evaluation sample when the actual
amount is greater than or equal to 0.010
mg/1.
(D) Achieve quantitative results on
the analyses performed under paragraph
(0(17)(i)(A) of this section that are
within ±40 percent of the actual amount
of the substances in the Performance
Evaluation sample when the actual
amount is less than 0.010 mg/1.
(E) Achieve a method detection limit
of 0.0005 mg/1, according to the
procedures in Appendix B of Part 138.
(ii) To receive certification for vinyl
chloride, the laboratory must
(A) Analyze Performance Evaluation
samples provided by EPA
Environmental Monitoring Systems
Laboratory or equivalent samples
provided by the State.
(B) Achieve quantitative results on the
analyses performed under paragraph
(0(17)(ii)(A) of this section that are
within- ±40 percent of the actual amount
of vinyl chloride in the Performance
Evaluation sample.
(C) Achieve a method detection limit
of 0.0005 mg/1, according to the
procedures in appendix B of part 136.
(D) Obtain certification for the
contaminants listed in $ 141.61(a)(2)
through (21).
(18) States may allow the use of
monitoring data collected after January
1,1988, required, under section 1445 of
the Act for purposes of initial monitoring
compliance. If the data are generally .
consistent with the other requirement*
of this section, the State may use these .
data (i.e., a single sample rather than :
four quarterly samples) to satisfy the
initial monitoring requirement of
-------
31842 Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulation
paragraph {f)(4) of this section. Systems
which use grandfathered samples and
did not detect any contaminant listed
§ 141.61(a)(2) through (21) shall begin.
monitoring annually in accordance with
paragraph (0(5) of this section beginning
with the initial compliance period.
« • • • •
(h) * * *
(10) The State may reduce the total
number of samples a system must
analyze by allowing the use of
compositing. Composite samples from a
maximum of five sampling points are
allowed, provided that the detection
= limit of the method used for analysis is
less than one-fifth of the MCL
Compositing of samples must be done in
the laboratory and analyzed within 14
days of sample collection.
• * • • «
(12) * * *
(ii) Method SOS. "Analysts of
Organohalide Pesticides and
Commercial Polychlorinated Biphenyl
Products (Aroclors) in Water by
Microcxtraction and Gas
Chromatography." Method 505 can be
used to measure alachlor, atrazine.
chlordane, endrin, heptachlor.
heptachlor epoxide, hexachlorobenzene,
hexachlorocyclopentadiene, lindane.
methoxychlor. toxaphene and simazine.
Method 505 can be used as a screen for
PCBs.
(Hi) Method 507. "Determination of
Nitrogen- and Phosphorus-Containing
Pesticides in Ground Water by Gas
Chromatography with a Nitrogen-
Phosphorus Detector." Method 507 can
be used to measure alachlor. atrazine
and simazine.
(iv) Method 508. "Determination of
Chlorinated Pesticides in Water by Gas
Chromatography with an Electron
Capture Detector." Method 508 can be
used to measure chlordane. endrin,
heptachlor. heptachlor epoxide,
hexachlorobenzene,.lindane,
methoxychlor and toxaphene. Method
508 can be used as a screen for PCBs.
******
(vi) Method 515.1. "Determination of
Chlorinated Acids in Water by Gas
Chromatography with an Electron
Capture Detector." Method-515.1 can be
used to measure 2,4-D, dalapon. dinoseb,
pentnchlorophenol, picloram and 2,4,5-
TP (Silvex).
(vii) Method 525.1, "Determination of
Organic Compounds in Drinking Water
by Liquid-Solid Extraction and Capillary
Column Gas Chromatography/Mass
Spectrometry." Method 525.1 can be
used to measure alachlor, atrazine,
chlordane, di(2-ethylhexyl)adipate. di(2-
ethylhexyljphthalate, endrin. heptachlor,
heptachlor epoxide, hexachlorobenzene.
hexachlorocyclopentadiene. lindane,
methoxychlor, pentachlorphenol.
polynuclear aromatic hydrocarbons,'
simazine. and toxaphene.
(viii) Method 531.1. "Measurement of
N-Methyl Carbamoyloximes and N-
Methyl Carbamates in Water by Direct
Aqueous Injection HPLC with Post-
Column Deriv'atization." Method 531.1
can be used to measure aldicarb,
aldicarb sulfoxide, aldicarb sulfone,
carbofuran and oxamyl.
(ix) Method 1613. 'Tetra- through
Octa- Chlorinated Dioxins and Furans
by Isotope Dilution." Method 1613 can
be used to measure 2.3,7,8-TCDD
(dioxin). This method is available from
USEPA-OST, Sample Control Center.
P.O. Box 1407. Alexandria, VA 22313.
(x) Method 547. "Analysis of
Glyphosate in Drinking Water by Direct
Aqueous Injection HPLC with Post-
Column Derivatization" Method 547 can
be used to measure glyphosate.
(xi) Method 548, "Determination of
Endothall in Aqueous Samples." Method
548 can be used to measure endothall.
(xii) Method 549, "Determination of
Diquat and Paraquat in Drinking Water
by High Performance Liquid
Chromatography with Ultraviolet
Detection." Method 549 can be used to
measure diquat.
(xiii) Method 550, "Determination of
Polycyclic Aromatic Hydrocarbons in
Drinking Water by Liquid-Liquid
Extraction and HPLC with Coupled
Ultraviolet and Fluorescence Detection".
Method 550 can be used to measure
benzo(a)pyrene and other polynuclear
aromatic hydrocarbons.
(xiv) Method 550.1. "Determination of
Polycyclic Aromatic Hydrocarbons in
Drinking Water by Liquid-Solid
Extraction and HPLC with Coupled
Ultraviolet and Fluorescence Detection".
Method 550.1 can be used to measure
benzo(a)pyrene and other polynuclear
aromatic hydrocarbons.
* • « • *
(18) Detection as used in this
paragraph shall be defined as greater
than or equal to the following -
concentrations for each contaminant.
Contaminant
Alachlor — _._.._ ....«._
Aidicarta :__.._../„.„__...
Aldicarb sutfoxxJ* ._ .......
Aldicarb suttone
BenzoCalpyreoff _ ,. .,. , M -
ChlordarM
Dicrornochloropropane (DBCP)
Di (2-ethythexyt) adipaia
Di (2-etftyftwxyt) pnthaltM
Detection
limit (mo/0
.0002
.0005
.0005
.0006
.0001
.00002
.0009
.0002
.001
.00002
.0009
.0008
Contaminant
Detection
limit (mg/1)
Dinoseb
Diquat
2.4-0
Endothall
Endrin _ _
Ethyton* abrorrwte (EQB)
Glyphosate
Heptachlor
Heplachkx epoxide
Hexachlorobenzene
Hexachlorocyclopentadiene
Undane
Methoxychlor
Oxamyl
Picloram
Polychlonnated biphenyls (PCBs) (as
decachlorobiphenyl)
Pentachtorophenol
Simazine „
Toxaphene
2.3.7.8-TCDD (Dioxin)
2.4,5-TP (Silvox) ..,
-1
.0002
.0004
.0001
.009
.00001
.00001
.006
.00004
.00002
.0001
.0001
.00002
.0001
.002
.0001
.0001
.00004
.00007
.001
.000000005
.0002
(19) * * *
(!)••*
(B) Achieve quantitative results on the
analyses that are within the following
acceptance limits:
Contaminant
OBCP _ _
EDB
Alachlor _
Atrazine -
Benzotalpyrene —
Carbofiran—
Chtordao*
Dalapon :.—, ,
Di(2-ethyt)exyr)adip«te ....
DK2-ethythexyf)prithalat»
Dinoseb.- - -
Dkjuat.,.-
EndothaH.._
Endnn _.
Glyphosate _
Heptachlor._ ,
Heptachlor epoxide ,
Hexachlorobenzene
Hexachloro-
cydopentadiena
U'ndan*
Methoxychlof
Oxamyl «.
PCSs'as
Decachlorobiphenyl)
Piclonvn
Simazin* — _,
Toxapherve............
Aldicarb.... ...
Aldicarb sulfmbde
Aldicarb suttone _
Pentachlorophenol ..
2.3,7,8-TCOO (Dioxin)...
2.4-O ........ ._.
2.4.5-TP (SivM)
Acceptance limits
(percent)
±40
±40.
2 standard deviations.
±45.
±45.
2 standard deviations.
2 standard deviations
2 standard deviations.
2 standard deviations.
2 standard deviations.
2 standard deviaDons.
2 standard deviations.
±45.
±45.
2 standard deviations.
2 standard deviations.
±45.
2 standard deviations.
0-200.
2 standard deviations.
2 standard deviations.
±45.
2 standard deviations.
2 standard deviations.
2 standard deviations.
±50,
2 standard deviations.
±50.
±50.
7. Section 141.32 is amended by
adding paragraphs (e)(53) through (75) to
read as follows:
-------
Federal Register / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations 31843
§141.32 Pm*c notmejUoo.
(53) Antimony. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that antimony is a health
concern at certain levels of exposure.- • •• -
This inorganic chemical occurs naturally
in soils, ground water and surface
waters and is often used in the flame
retardant industry. It is also used in
ceramics, glass, batteries, fireworks and
explosives. It may get into drinking
water through natural weathering of
rock, industrial production, municipal
waste disposal or manufacturing
processes. This chemical has been
shown to decrease longevity, and
altered blood levels of cholesterol and
gfucose in laboratory animals such as •
rats exposed to high levels during their
lifetimes. EPA has set the drinking water
standard for antimony at 0.006 parts per
million (ppm) to protect against the risk
of these adverse health effects. Drinking
water which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to antimony.
(54) Beryllium. The United Slates
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that beryllium is a health
concern at certain levels of exposure.
This inorganic metal occurs naturally in
soils, ground water and surface waters
and is often used in electrical equipment
and electrical components. It generally
gets into water from runoff from mining
operations, discharge from processing
pfants and improper waste disposal.
Beryllium compounds have been
associated with damage to the bones
end lungs and induction of cancer in
Saboratory animals such as rats and
mice when the animals are exposed at
feigh levels over their lifetimes. There is
Simited evidence to suggest that
beryllium may pose a cancer risk via
drinking water exposure. Therefore.
EPA based the health assessment on
noncancer effects with an extra
uncertainty factor to account for
possible carcinogenicity. Chemicals that
cause cancer in laboratory animals also
nay increase the risk of cancer in
humans who are exposed over long
.periods of time. EPA has set the drinking
water standard for beryllium at 0.004
part per million (ppm) to protect againrt
&e risk of these adverse health effects.
Drinking water which meeti the EPA
standard is associated with little to none
of this risk and should be considered
sife with respect to beryllium.
(55) Cycnfdc. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that cyanide is a health
concern at certain levels of exposure.
This inorganic chemical is used in
electroplating, steel processing, plastics.
synthetic fabrics and fertilizer products.
It usually gets into water as a result of
improper waste disposal. This chemical''
has been shown to damage the spleen.
brain and Kver of hunwins fatally
poisoned with cyanide. EPA has set the
drinking water standard for cyanide at
0.2 parts per million (ppm) to protect
against the risk of these adverse health
effects. Drinking water which meets the
EPA standard is associated with Httle to
none of this risk and should be
considered safe with respect to cyanide.
(56) Nickel. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that nickel poses a health
concern at certain levels of exposure.
This inorganic metal occurs naturally in
soils, ground water and surface waters
and is often used in electroplating,
stainless steel and alloy products, it
generally gets into water from mining
and refining operations. This chemical
has been shown to damage the heart
and liver in laboratory animals when
the animals are exposed to high levels
over their lifetimes. EPA has set the
drinking water standard at 0.1 parts per
million (ppm) for nickel to protect
against the risk of the*: adverse effects.
Drinking water which meets the EPA
standard is associated with little to none
of this risk and should be considered
safe with respect to nickel.
(57) Thallium. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that thallium is a health
concern at certain high levels of
exposure. This inorganic metal is found
naturally in soils and LSI used in
electronics. Pharmaceuticals, and the
manufacture of glass and alloy*. This
chemical has been* shown to damage the
kidney, liver, brain and. intestines of
laboratory animals wtu:n the animals
are exposed at high levels over their
lifetimes. EPA has set the drinking water
standard for thallium at OJJQ2 parts per
million (ppm) to protect against the risk
of these adverse health effects. Drinking
water which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to thallium.
(58) Benzofajpyreije. The United
States Environmental Protection Agency
(EPA) sets drinking, water standards and
has determined that benzo[alpyrene is a
health concern at certain lev*ls of
exposure. Cigarette s«mt.B sn4 .
charbroiled meats are commorv source of
genera! exposure. The major source of
benzo[a)pyrene in drinking water is the
leaching from coal tar lining and
sealants in water storage tanks. This
chemical has been shown to cause
cancer in animals such as rats and mice
when the animals are exposed at high
levels. EPA has set the drinking water .
standard for benzo[aJpyrene at 0.0002
parts per million (ppm) to protect
against the risk of cancer. Drinking
water which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to benzo[ajpyrene.
(59) Dalapon. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that dalapon is a health
concern at certain levels of exposure.
This organic chemical is a widely used
herbicide. It may get into drinking water
after application to control grasses in
crops, drainage ditches and along
railroads. This chemical has been shown
to cause damage to the kidney and liver
in laboratory animals when the animals
are exposed to high levels over their
lifetimes. EPA has set the drinking water
standard for dalapon at 0.2 parts per
million (ppm) to protect against the risk
of these adverse health effects. Drinking
water which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to dalapon.
(60) Dichloromethane. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that dichloromethane
(methylene chloride] is a health concern
at certain levels of exposure. This
organic chemical is a widely used
solvent It is used in the manufacture of
paint remover, as a metal degreaser and
as an aerosol propellant. It generally
gets into drinking water after improper
discharge of waste disposal. This
chemical has been shown to cause
cancer hi laboratory animals such as
rats and mice when the animals are
exposed at high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals alto may increase
the risk of cancer In humans who are
exposed over long periods of time. EPA
has set the drinking water standard for
dichloromethane at 0.005 parti per
million (ppm) to reduce the risk of
cancer or other adverse health effects
which have been observed in laboratory
anfmats. Drinking water which meets
this standard is associated with tittle to
none of this risk and should be
considered safe with respect to
dichloromethane.
(&l)Di(Z-ethy!/iexyfJadipate. The
United States Environmental Protection
Agency (EPA) sets drinking water
-------
31844 Federal RegJater / VoL 57. No. 138 / Friday. July 17. 1992 / Rulea and Regulations
standards and has determined that di(2-
ethylhexyl)adipate is a health concern
at certain levels of exposure. Di(2-
elhylhexyl)adipate is a widely used
plasticizer in a variety of products.
including synthetic rubber, food
packaging materials and cosmetics. It
may get into drinking water after
improper waste disposal. This chemical.
has been shown to damage liver and
testes in laboratory animals such as rats
and mice exposed to high levels. EPA
has set the drinking water standard for
di(2-ethylhexyl)adipate at 0.4 parts per
million (ppm) to protect against the risk
of adverse health effects. Drinking water
which meets the EPA standards is
associated with little to none of this risk
and should be considered safe with
respect to di(2-ethylhexyl)adipate.
(62) Di(2-ethylhexyl)phthalate. The
United States Environmental Protection
Agency (EPA) sets drinking water
standards and has determined that di(2-
ethylhexyljphthalate is a health concern
at certain levels of exposure. Di(2-
ethylhexyljphthalate is a widely used
plasticizer. which is primarily used in
the production of polyvinyl chloride
(PVC) resins. It may get into drinking
water after improper waste disposal.
This chemical has been shown to cause
cancer in laboratory animals such as
rats and mice exposed to high levels
over their lifetimes. EPA has set the
drinking water standard for di(2-
elhylhexyljphthalate at 0.004 parts per
million (ppm) to reduce the risk of
cancer or other adverse health effects
which have been observed in laboratory
animals. Drinking water which meets
the EPA standard is associated with
little to none of this risk and should be
considered safe with respect to di(2-
ethylhexyl)phthalate.
(63) Dinoseb. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that dinoseb is a health
concern at certain levels of exposure.
Dinoseb is a widely used pesticide and
generally gets into drinking water after
application on orchards, vineyards and
other crops. This chemical has been
shown to damage the thyroid and
reproductive organs in laboratory
animals such as rats exposed to high
levels. EPA has set the drinking water
standard for dinoseb at 0.007 parts per
million (ppm) to protect against the risk
of adverse health effects. Drinking water
which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to dinoseb.
(64) DlquaL The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that diquat is a health
concern at certain levels of exposure.
This organic chemical is a herbicide
used to control terrestrial and aquatic
weeds. It may get into drinking water by
runoff into surface water. This chemical
has been shown to damage the liver.
kidney and gastrointestinal tract and
.' causes cataract-formation in-laboratory
animals such as dogs and rats exposed
at high levels over their lifetimes. EPA
has set the drinking water standard for
diquat at 0.02 parts per million (ppm) to
protect against the risk of these adverse
health effects. Drinking water which
meets the EPA standard is associated
with little to none of this risk and should
be considered safe -with respect to
diquat.
(65) Endothall. The United States
Environmental Protection Agency (EPA)
has determined that endothall is a
health concern at certain levels of
exposure. This organic chemical is a
herbicide used to control terrestrial and
aquatic weeds. It may get into water by
runoff into surface water. This chemical
has been shown to damage the liver,
kidney, gastrointestinal tract and
reproductive system of laboratory
animals such as rats and mice exposed
at high levels over their lifetimes. EPA
has set the drinking water standard for
endothall at 0.1 parts per million (ppm)
to protect against the risk of these
adverse health effects. Drinking water
which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to endothall.
(66) Endrin. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that endrin is a health
concern at certain levels of exposure.
This organic chemical is a pesticide no
longer registered for use in the United
States. However, this chemical is
persistent in treated soils and
accumulates in sediments and aquatic
and terrestrial biota. This chemical has
been shown to cause damage to the
liver, kidney and heart in laboratory
animals such as rats and mice when the
animals are exposed at high levels over
their lifetimes. EPA has set the drinking
water standard for endrin at 0.002 parts
per million (ppm) to protect against the
risk of these adverse health effects
which have been observed in laboratory
animals. Drinking water that meets the
EPA standard is associated with little to
none of-this risk and should be
considered safe with respect to endrin.
(67) Glyphoaate. The United State*
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that glyphosate is i health
concern at certain levels of exposure.
This organic chemical is a herbicide
used to control grasses and weeds. It
may get into drinking water by runoff
into surface water. This chemical has
been shown to cause damage to the liver
and kidneys in laboratory animals such
as rats and mice when .the animals are- '••:•
• exposed at high levels over their
lifetimes. EPA has set the drinking water
standard for glyphosate at 0.7 parts per
million (ppm) to protect against the risk
of these adverse health effects. Drinking
water which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to glyphosate.
(88) HexaChlorobenzene. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that hexachlorobenzene
is a health concern at certain levels of
exposure. This organic chemical is
produced as an impurity in the
manufacture of certain solvents and
pesticides. This chemical has been
shown to cause cancer in laboratory •
animals such as rats and mice when the
animals are exposed to high levels
during their lifetimes. Chemicals that
cause cancer in laboratory animals also
may increase the risk of cancer in
humans who are exposed over long
periods of time. EPA has set the drinking
water standard for hexachlorobenzene
at 0.001 parts per million (ppm) to
protect against the risk of cancer and
other adverse health effects. Drinking
water which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to hexachlorobenzene.
(69) Hexachlorocyclopentadiene. The
United States Environmental Protection
Agency (EPA) establishes drinking
water standards and has determined
that hexachlorocyclopentadiene is a
health concern at certain levels of
exposure. This organic chemical is used
as an intermediate in the manufacture of
pesticides and flame retardants. It may
get into water by discharge from
production facilities. This chemical has
been shown to damage the kidney and
the stomach of laboratory animals when
exposed at high levels over their
lifetimes. EPA has set the drinking water
standard for hexachlorocyclopentadiene
at 0.05 parts per million (ppm) to protect
against the risk of these adverse health
effects. Drinking water which meets the
EPA standard is associated with little to
none of this risk and should be
considered safe with respect to
hexachlorocyclopentadiene.
(7Q\Oxamyl. The United States
Environmental Protection Agency (EPA)
establishes drinking water standards
-------
/ Vot. S7; No. 13« / Ffkiay, July 17. 1992 / Rnles am! Regulations
and has determined that oxamyl is a
health concern at certain levels of
exposure. This organic chemical is used
as a pesticide for the control of insects
and other pests. It may get into drinking
water by runoff into surface water or
leaching into ground water. This
chemical has been shown, to.damage the •.
kidneys of laboratory animals such as
rats when exposed at high levels over
their lifetimes. EPA has set .the drinking
water standard for oxamyl at 0.2 parts
per million (ppm) to protect against the
risk of these adverse health effects.
Drinking water which meets the EPA
•standard is associated with little to none
of this risk and should be considered
safe with respect to oxamyL
(71) Picloram. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has
determined that picloram is a health
concern at certain levels of exposure.
This organic chemical is used as a
pesticide for broadleaf weed control. It
may get into drinking water by runoff
into surface watnr or leaching into
ground water as a result of pesticide
application and improper waste
disposal. This chemical has been shown
to cause damage to the kidneys and
liver in laboratory animals such as rats
when the animals are exposed at high
levels over their lifetimes. EPA has set
the drinking water standard for picloram
at 0.5 parts per million (ppm) to protect
against the risk of these adverse health
effects. Drinking water which meets the
EPA standard is associated with little to
none of this risk and should be
considered safe with respect to
picloram.
(72) Simazine. The United States
Environmental Protection Agency (EPA)
sets drinking water standards and has.
determined that simazine is a health
concern at certain levels of exposure.
This organic chemical is a herbicide -
used to control annual grasses and
broadleaf weeds. It may leach into
ground water or runs off into surface
water after application. This chemical
may cause cancer in laboratory animals
such as rats and mice exposed at high
levels during their lifetimes. Chemicals
that cause cancer in laboratory animals
also may increase the risk of cancer in
humans who are exposed over long
periods of time. EPA has set the drinking
.water standard for simazine at 0.004
parts per million (ppm) to reduce the
risk of cancer or other adverse health
effects. Drinking water which meets the
EPA standard is associated with little to
none of this risk and should be .
considered safe with respect to
simazine.
(73) 13,4-TrichJombenze/ie. The
United States Environmental Protection
Agency (EPA) seta drinking water
standards and has determined that 1.2.4-
trichlorobenzene is a health concern at
certain levels of exposure. This organic
chemical is used as a dye carrier and as
a precursor in herbicide manufacture. It.
generally gets into drinking water by
discharges from industrial activities.
This chemical has been shown to cause
damage to several organs, including the
adrenal glands. EPA has set the drinking
water standard for 1,2,4-
trichlorobenzene at 0.07' parts per
million (ppm} to protect against the risk
of these adverse health effects. Drinking
water which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to 1.2.4-trichlorobenzene.
(74) 1.13-Trichhroethane. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined 1,1.2-tricbloroethane is a
health concern at certain levels of
exposure. This organic chemical is an
intermediate in the production of 1.1-
dichloroethytene. It generally gets into
water by industrial discharge of wastes.
This chemical has been shown to
damage the kidney and liver of
laboratory animals such as rats exposed
to high levels during their lifetimes. EPA
has set the drinking water standard for
1.1.2-trichloroethane at 0.005 parts per
million (ppm) to protecJ against the risk
of these adverse health effects. Drinking
water which meets the EPA standard is
associated with little to none of this risk
and should be considered safe with
respect to 1.1.2-trichloroetbane,
(75) 2.3,7,8-TCDD (DioxJn). The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that dioxin is a health
concern at certain levels of exposure.
This organic chemical is an impurity in
the production of some pesticides. It
may get into drinking water by
industrial discharge of wastes. This
chemical has been shown to cause
cancer in laboratory animals such as
rats and mice when the animals are
exposed at high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humane who are
exposed over long periods of time. EPA
has set the drinking water standard for
dioxin at 0.00000003 pacts per million
(ppm) to reduce the risk of cancer or
other adverse tessltk effects which have
been observed in laboratory animals.
Drinking water which meets this
standard is associated with little to none
of this risk and should be considered
safe with respect to dioxin.
8. Section 141.40 is amended by
revising paragraph (e\, revising
paragraph (f). revising paragraphs (g)
and (h). and revising paragraphs (n) (11)
and (12) including the tables to read as
follows:
§141.40 Special monitoring for organic ..,
(e) Community water systems and
non-transient, non-community water
systems shall monitor for the following
contaminants except as provided in
paragraph (f) of this section:
(1) Chloroform
f2)- Bromodichloromethane
(3) Chlorodibromomethane
(4) Bromoform
(5) Chlorobenzene
•(6) m-Dichlorobenzene
(8) 1.1-Dichloropropene
(9) 1.1-Dichloroethane
(10) 1.1.2,2-Tetrachloroethane
(11) 1.3-Dichloropropane
(12) Chloromethane
(13) Bromomethane
(14) 1.2,3-Trichloropropane
(15) 1.1.1.2-Tetrachloroethane
(16) Chloroethane
(17J 2.2-Dichloropropane
(18) o-Chlorotoluene
(19) p-Chlorotoluene
(20) Bromobenzene
(21) i:3-Dichloropropene
(f) [Reserved]
(g) Analysts under this section shall
be conducted using the recommended
EPA methods as follows, or their
equivalent as determined by EPA: 502.1.
"Volatile Halogenated Organic
Compounds in Water by Purge and Trap
Gas Chromatography," 503.1. "Volatile
Aromatic and Unsaturated Organic
Compounds in Water by Purge and Trap
Gas Chromatography." 524.1. "Volatile
Organic Compounds in Water by Purge
and Trap Gas Chromatography/Mass
Spectrometry." 524.2, "Volatile Organic
Compounds in Water by Purge and Trap
Capillary Column Gas Chromatography/
Mass Spectrometry, or 502.2. "Volatile
Organic Compounds in Water by Purge
and Trap Gas Chromatography with
Photoionization and Electrolytic
Conductivity Detectors m Series." These
methods are contained in "Methods for
the Determination of Organic
Compounds in Finished Drinking Water
and Raw Source Water." September
1988. available from the Drinking Water
Public Docket or the National Technical
Information SenrfcarfNTIS). NTTS PB91-
231480 and PB91-146027, U:S; * '
Department of Commerce, 5285 Port-
Royal Road. Springfield. Virginia 22161.
The toll-free number is 800-336-4700.
-------
31846
Fedaral Regute, / VoL 57. No. 13* / Friday. July 17. 1992 / Rnles
(h) Analysis under this section shall
only be conducted by laboratories
approved under § 141.24(g)(ll).
(11) List of Unregulated Organic
Contaminants:
Organic contammann ', EPA analytic* matnod
(22) Hexachlorobenzene
(23) 2.3.7,8-TCDD (Dioxin)
(b) ' * *
Contaminant
MO.G (mg
1)
AJdon „.,..„„.„ ,._...
Bulacnlor „..,.„
Camaryt,,..., „
Dicamba ™
DteWfin
3-Hyatoxycart>ofuran...."
Melhomy) .„.....„.„ „..,
Meiotachlor,, J
Meinbuiin..
Pf opachtor «..™...™.....
—: 505. 508. and 525
• 507. 525_
,...1 581.1.
...J 515.1.
....I 505. 508. and 525.
..-! 581.1.
...J 531.1.
....| 507. 525.
.-.! 507. 508. and 525.
... J 507. 525.
(12) List of Unregulated Inorganic
Contaminants:
Inorganic coniammams
EPA analytical
me mod
<21) Oalapon..:.
(22) Oi(2-etnyth«xyf)adipate.
(23) Dinowb
(24) DiQuat
(25) EndotnaM „
(26)Endrin .".".':.'".'.'.".'."."
(27) Glyphosata """! •
(28) HexacWorccyctopentadwoi'.'!
(29) Oxamyi (Vydata)
(30) Pickxam
(31) Simazme Z.....1.."
(32) 1.2.<-Trichtofoben2en«""
(33) 1.1,2-Tnchtofoetnan*
0.2
.4
.00
.02
.1
.002
.7
.05
.2
.5
.004
.07'
.003
.,_......... Cotonmetnc,
9. Section 141.50 is amended by
adding paragraphs (a)(19) through
(a (23) and paragraphs (b)(21) through
(b](33) in the table in paragraphs (b) as
follows:
§ 141.50 Maximum contaminant l«v«l
goals for organic chamtealt.
(a) ' • •
(19) Benzofajpyrene
(20) Dichloromethane (methylene
chloride)
(21) Di(2-ethylhexyl)phthalate
10. Section 141.51 is amended by
adding entries (b)(ll) through (b)(l5) as
follows:
5 141.51 Maximum contaminant tevtJ
8oal« for Inorganic contaminant*
(b) * « •
Contaminant
MCLG (mg/
1)
(11) Antimony
(12) Beryllium
(13) Cyanide (as tree Cyanide).:
(14) Nickel
(15) Thallium
0.006
.004
.2
.1
.0005
9141.60 Effective data*.
(a)' ' '
(3) The effective date for paragraphs
(a)(19) through (a)(21) and (c)(19)
through (c)(33) of § 141.61 is January 17.
(b) * • •
(3) The ef/ective.date for paragraphs-
b)(ll) through (b)(15) of 8 141.62 is
January 17. 1994.
12. Section 141.61 is amended by
adding paragraphs (a)(19)-{21); by
revising paragraph (b) including the
table: by revising the introductory text
to paragraph (c): and by adding
paragraphs (c)(19}-{33).
5 141.81 Maximum contaminant
organic contaminant*.
for
CAS No.
Contaminant MCL (mg/l)
19) 75-09-2
20) 120-82-1
21) 79-00-5
Dichtorometnane....
1.2.4-TncNoro-
benzene.
1.1.2-Tncnkxo-
etnane.
0005
.07
.005
11. Section 141.60 is amended by
adding paragraphs (a)(3) and fb)(3) to
read as follows:
(b)The Administrator, pursuant to
ection 1412 of the Act. hereby identifies
s indicated in the Table below granular
ctivated carbon (GAG), packed tower
eration (PTA), or oxidation (OX) as the
est technology treatment technique, or
ther means available for achieving
compliance with the maximum
contaminant level for synthetic organic
contaminants identified in paragraphs
(a) and (c) of this section:
BATFOR ORGANIC CONTAMINANTS LISTED IN SECTION 141.61 (A) AND
(c)
50-32-8
75-99-0
75-09-2
103-23-1
117-81-7
88-85-7
85-00-7
145-73-3
72-20-45
1071-53-6
1 18-74-1
Dalapon
Dchtofometnane ........
Di (2-«thyff>exyl) adipate
Oi (2-«thylneryl) phthalals
Dino»et)...._
Douat..... "
Enoothall
Enonn
Glypoosata
Hexacfttofooennna ...
»,
23135-22-0
1918-02-1
122-34-8
120-82-1
79-00-5
1746-01-«
CTwmyl (Vydala)
Pxaofam
SJmanna
1.1.2-TncNofoethan*
2.3.7.8-TCDD (Diorin)
GAC
PTA
X
X
X
X
X
ox
X
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Federal Register / Vol. 57. No. 138 / Friday, fuly 17, 1992 / Rules and Regulations 31847
CAS No.
Contaminant
MCL|mg/l)
09)
(25) '
ipfit
(321
. . 50-32-*
75-99-0
103-23-1
117-81-7
88-85-7
85-00-7.
145-73-3
• • 72-20-8
1071-53-6
118-74-1
77-47-4
23135-22-0
1918-02-1
122-34-9
1746-01-6
BanzofaJpyrene
Dalapcifi T- -
Di(2-ethylrie)ryl) adipate .'.
f>(2-ethylhexyl) pntnalate
Dinoseto . '. -
EndotfwM
Endnn
Gtyphosate
Hexacl*io(orbef>zef>o
HexacWorocyctopentadiene
Oxamyl (Vydate) . .
2 3,7.8-TCOD (Dtoxm) .-. ;
0.0002
0.2
0.4
0.006
0007
002..,
0.1
0.002
O.V
0001
0.05
0.2
0.5
0004
3- 10 •
3. Section 141.62 is amended by
revising the introductory text to
paragraph (b): by adding paragraphs
(b){ll) through (b){15); and by revising
paragraph (c), including the table, to
read as follows:
§ 141.62 Maximum contaminant levels for
Inorganic contaminants.
• * * • *
(b) The maximum contaminant levels
for inorganic contaminants specified in
paragraphs (b)(2J—(6). (b)(10). and
(b)(ll}—{15) of this section apply to
community water systems and non-
transient, non-community water
systems. The maximum contaminant
level specified in paragraph (b)(l) of this
section only applies to community water
systems. The maximum contaminant
levels specified in (b)(7). (b)(8). and
(b)(9) of this section apply to community
water systems; non-transient, non-
community water systems: and transient
non-community water systems.
Contaminant
MCL (mg/l)
* • • e e
b.oos
„ -0.004
.. .. -0.2
0.1
0.002
(c) The Administrator, pursuant to
Section 1412 of the Act, hereby
identifies the following as the best
technology, treatment technique, or
other means available for achieving
compliance with the maximum
contaminant levels for inorganic
contaminants identified in paragraph (b)
of this section, except fluoride:
BAT FOR INORGANIC COMPOUNDS LISTED
IN SECTION 141.62(8}
Chemical Name
A3t>63tO3 '...,.,, ,.,,r,.....,
Bsnuni i
Beryfhum
C^arwde
ttcfcaj
Nrfratv „
N&ftTte ;
Sfttonium
BAT(S)
2.7
2.3.8
5.6.7.9
1.2.5.6.7
2.5,6.7
' 2.5.6 »,7
5.7,10
2 ' *6 ' 7 '
5.6.7
5.7.9
5.7
1.2 '.6.7.9
1,5
1 BAT only rf influent Hg concentrations <10jig/1.
1 BAT lor Chromium III ooty.
1 BAT (or Seicmum IV orty.
Key to BATS in Table
1 = Activated Alumina
2 = Coagulation/Filtration
3 = Direct and Diatomite Filtration
4 = Granular Activated Carbon
5 = Ion Exchange
6=Lime Softening
7 = Reverse Osmosis
8=Corrosion Control
9 = Electrodialysis
10=Chlorine
ll = Ultraviolent
14. Section 141.89(a) table is amended
by revising footnote 9 to read as follows:
§141.99 Analytical methods.
• * • • •
• For analyzing lead and copper, the
technique applicable to total metals
must be used and samples cannot be
filtered. Samples that contain less than 1
NTU (nephelometric turbidity unit) and
are properly preserved (cone HNO» to
pH <2) may-i>e analyzed directly
(without digestion) for total metala:
otherwise, digestion ia required.
Turbidity must be measured on the
preserved samples just prior to when
metal analysis is initiated. When
digestion is required, the 'total
recoverable' technique as defined in the
method must be used.
PART 142—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
IMPLEMENTATION
1. The authority citation for part 142
continues to read as follows:
Authority: 42 U.S.C. 300g. 300g-l. 300g-2,
300g-3.300g-4. 300g-5.300g-fl, 300H and
300J-9.
2. Section 142.16 is amended by
revising the introductory text to
paragraph (e), and revising paragraph
(e)(2) to read as follows:
} 142.16 Special Primary Requirements.
• • * * . «
(e) An application for approval of a
State program revision which adopts the
requirements specified in 8 5 141.11.
141.23.141.24.141.32.141.40.141.61 and
141.62 must contain the following (in
addition to the general primacy
requirements enumerated elsewhere in
this Part including the requirement that -
State regulations be at least as stringent
as the federal requirements):
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31848
Federal Ragbter / Vol. 57. No. 138 / Friday. July 17. 1992 / Rules and Regulations
(2) A monitoring plan for the initial
monitoring period by which the State will
assure all system* complete the required
initial monitoring within the regulatory
deadlines.
Not*: States may update their monitoring
plan submitted under the Phase II Rule or
§ imply note in their application that they will
use the same-monitoring plan for the Phase V
Rule.
(!) The Initial monitoring plan must
describe how systems will be scheduled
during the initial monitoring period and
demonstrate that the analytical workload on
certified laboratories for each of the three
years has been taken into account, to assure
that the State's plan will result in a, high
degree of monitoring compliance and that a*
a result there is a high probability of
compliance and will be updated as
necessary.
(ii) The State must demonstrate.that the..
initial monitoring plan is enforceable under
Slate law.
3. Section 142.62 is amended by
revising paragraphs (a) and (b) to read
as follows:
§ 142.62 Variance* and exemption* from
the maximum contaminant levels for
organic end Inorganic chemicals.
(a) The Administrator, pursuant to
section 1415(a){l)(A) of the Act hereby
identifies the technologies listed in
paragraphs (a)(l) through (a)(54) of this
section as the best technology. •••
treatment techniques, or other means
available for achieving compliance with
the maximum contaminant levels for
organic chemicals listed in § § 141.61 (a)
and (c):
Contaminant
Best available technologies
PAT '
GAO1
OX'
X
(2> Carcon tttrachtood*. X
(3) 1.2-Dichloroothaoe. — - X
(4) Tnchkxoetftyleoe, • X
(5) gara-OicMorooanzeno - - —~ X
(6) 1.1-OiChlOfO««>yten« _ j X
(7) 1.1.1-Tncnkxoethana - X
(8) Wtyt crrfonda ...™ -.«.. ~..— X
(9) os«1.2-OicNofo*triyi*oo..-...«. •...« «. - - - X
-• • -' "" ~ x
(12) MooocWofobenzena - •• X
X
(15) T»tracnkXO«kx
(33) PCSs „
(34) Panlacnlofoph«nol...
(35) Tonaphorvo,,,. ,
(36) 2.4.S-TP „
(37) 8*nzota]pyrena —
(38) Oatapona,
(40) r>(2-«t»»y1b«!Eyt)ado«»« _ X
(41) O(2-clhy)heiyl)pwnalalo,.
(42) &oosab .«
(43) CVy^if^ i
(44) Eretotnax
(45) Endnn..„........_.._...,..___,.
(46) GlypfOMte............. _,.
(47) Hatactvkxobenzene
(48) HaxacWofocyclopofltad^na _ _.... _«..««......«. ,,, , , -,- x
(49) Oxamy< (VydaM).
(SO)P>ekxam,
(52) 1^.4-TnerJocoo«oMoe 3 X
(53) 1.1J!'Tnchloroe«>a«t ~ - ..'....
(5«) 2.3.7,8-TCOO (Ocxjn)
1 Packad Toww Aarabon
'GranO* ActrvmXd Cannon
'Ouda&on (CNoonaton or Otonaao^
(b) The Administrator, pursuant to
section 1415(aXl)(A) of tha Act, hsreby
identifies "tha following as the best
technology, treatment technique*, or
other means available for achieving
compliance with the maximum
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Federal Register / Vol. 57, No. 138 / Friday, July 17, 1992 / Rules and Regulations
31849
contaminant levels for the inorganic
chemicals listed in 5 141.62:
BAT FOR INORGANIC COMPOUNDS LISTED
IN M 4 1.62(8)
Chemical name . BATts)
Antimony*. - .
Nickel • '
2.7
2.3.8
5.6.7.9
1.2.5.6.7
2.5.6.7
2.5.6 '.7
5.7.10
2 '.4.6 \7 '
5.6.7
BAT FOR INORGANIC COMPOUNDS
IN « 1 4 1 .62(8)— Continued
LISTED
Chemical name j 8AT(s)
Nitrite I
Thallium ~ . - |.
1 BAT only if influent Hg concentrations
1 SAT (of Chromium III only.
5 BAT lor Selenium IV only.
Key to BATS in Table
1 = Activated Alumina •
5.7.9
5.7
1 2 '.6.7.9
1.5
-.10*19/1
2=Coagulation/Filtration (not BAT for
systems < 500 service connections)
3 = Direct and Diatomite Filtration
4 = Granular Activated Carbon
5 = Ion Exchange
8= Lime Softening (not BAT for systems
< 500 service connections)
7 = Reverse Osmosis
8=CorroBkm Control • - •
9 = Electrodialysis
10 = Chlorine
11 = Ultraviolet
[FR Doc. 92-15580 Filed 7-16-92; 8:45 amj
BILLING COOf 8MO-SO-M
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