United Stsfe* Scl««* AAaswy io»fd
gwrireniTMntd A-101
Pr«*otfon Agency Washington, DC
AN SAB REPORT:
EVALUATION OF THE
GUIDANCE FOR THE GREAT
LAKES WATER QUALITY
INITIATIVE
PREPARED JCiNTLY BY THE
GREAT LAKES WATER QUALITY
SUBCOMMITTEE OF THE
ECOLOGICAL PROCESSES AND
EFFECTS COMMITTEE AND THE
DRINKING WATER COMMITTEE
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UMTiD STATES SNVIRONMB^TAL PflOTECTTON,
WASHINGTON D.C. 20460
December 16, 1992
OFFICE OF
TH£ ADMINISTRATOR
SCIENCE ADVISOR* BQARO
EPA-SAB-EPEC/DWC-98.005
Honorable William Reffly •
Administirator
U.S. Environmental Protection Agency
401 M Street, S.W. "
Washington, B.C. 20460
Subject; SAB. Review of Guidance for the Great Lakes Water
Quality Initiative
Dear Mr. Bfiilly:
The Science Advisory Board (SAB) has completed its review of four
technical guidance documents for developing water qualiiy criteria m the Great
Lakes Basin, This guidance was developed by EPA in collaboration with states in
the Great Lakes Basin and is intended for application in this region. This review
covered a wide range of disciplines, and included the expertise^ of both the
Ecological Processes and Effects Committee (EPEC) aid the Drinking Water
Committee (DWC) of the SAB. The SAB conducted this review in response to an
extensive charge from EPA Region V which asked for review on aquatic life,
wildlife, and human health criteria guidance and a new approach for assessing
bioaccumulation. EFEC formed a Great Lakes Water Quality Subcommittee to
coordinate the review. The Subcommittee evaluation focustd on the following
issues from the charge: 1) the validity and proposed uses of Tier 2 aquatic life
criteria; 2} the wildlife criteria approach, including species selected, the data used,
and the use of Toxicity Equivalency Factors (TEFs); and 3} tht use and
calculation of bioaecumulation factors. The Subcommittee and the Drinking Water
Committee addressed the human health criteria for carcinogens and mim™1™ data
sets for each tier.
Four public meetings were conducted, including two meetings by the Drinking
Water Committee (focused on Human Health Criteria) and a meeting of the Dioxm
Ecotox Subcommittee of EPEC which included TEFs for aquatic life and wildlife.
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Tlie Great Lakes Wtter Quality Initiative (GLWQI) is a challenging and
ambitious endeavor. Tilt SAB commends EPA for tlie interactions among the
states, EPA, the private sector and the scientific community in further developing
environmental protection programs for the Great Lakes. This program should also
actively involve interests in Canada and seek a consistent U.S.-Canadian approach,
Based on the documents reviewed and tht presentations made to the panels it is
unclear how the Great Lakes region is unique in water quality problems and
issues. The Subcommittee recommends that the EPA provide more background
information on the sources and effects of chemicals discharged to the Great Lakes
and the nature of the exposures. The GLWQI should revise its introduction to
discuss its rationale for an initiative in the Great Lakes; a history of contaminant ~
related ecological problems; and a discussion of environmental issues associated
with the Great Lakes. These would be of value to place the GLWQI in
perspective.
The Subcommittee also recommends that tht EPA promote a broadly based
ecosystem approach which considers not only point source discharges but non-
point sources, sediments, atmospheric fall-out, and grouadwater as targets for
conservation and control of undesirable loadings (i.e., levels which have a toxic
effect). Likewise, the EPA should consider other pathways of exposure and
endpoints of effects for wildlife and humans,
The Subcommittee supports the principle of using Tier 1 and Tier 2 data in
developing water quality protective of aquatic life, wildlife and humans. The Tier
1 criteria have data sets equivalent to the National Water Quality Criteria, The
Tier 2 approach is used to develop criteria for contaminants which have less data.
The Subcommittee recommends that the Tier 2 tniniirmm data base for aquatic life
include estimates of chronic fcoxicity and assess, matrix effects on toxicity, We
caution EPA against setting inflexible numeric standards based on Tier 2. Tier 2
derived values should be used as an incentive to improve the underlying data base
for Tier 2 chemicals.
The Subcommittee supports the GLWQfs efforts to develop an approach to
protect wildlife from thi tffects of bioaceumulative chemicals in the tnvironment
However, the Subcommittee is concerned that the current approach does not
adequately consider ecologically important species in selection of surrogate wildlife
species and it relies on human health procedures that are more appropriate for
protection of individuals than for "local or regional wildlife populations. Similarly,
the Subcommittee feels that the definition of wildlife is ambiguous and
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recommends that EPA and the GLWQI develop a definition of wildlife and justify
species Inclusions and exclusions.
The form of the contaminant and the analytical methods to measure criteria
concentrations deserves further discussion in the guidance. The Subcommittee
recommends that values for both the biologically active form of contaminants and
the total concentration he included In water quality criteria. Guidance should be
provided for monitoring instances where water quality standards result in water
concentrations that are well below detection limits of currently accepted analytical
methods,
The Subcommittee notes that the- GLWQI appears to haw no elements
which predict the persistence of chemicals. The proposed approaches also do not
consider rates of degradation, hydrolysis, volatilization, sorption and all of the
environmental transport and fate pathways. The approach for assessing
bioaccumulation factors CBAF) advanced in the GLWQI uses octanol/water
partition coefficients (Log P) and food chain models to predict residues la biota.
Other approaches to estimate persistence should also be explored, such as, using
biological residues and partitioning- methods with C18 and/or Tessx,
We are concerned that the Great Lakes Initiative human health risk
assessment methodology is not using the most updated approaches being used by
EPA and others. Tier I criteria for human health should bt limited to chemicals
with good data on earcinog enesis, reproductive and developnfental/ ttratogenie
effects. The linear multistage model is a reasonable default methodology for
chemicals which lack more detailed information on their modes of action, Ideally,
additivity should not be used as a default, but rather multiple carcinogens should
be considered on a case by case basis. We encourage EPA to use a variety of
broad criteria to classify chemicals as Tier 2 to encourage improvements in the
data base, The Subcommittee recommends that the draft human health criteria
documents and guidance for their development be revised to improve the analysis
and presentation of data and rationale for the development of the criteria*
It is the SAB's understanding that the draft guidance and implementation
procedures will be published in the Federal Ifegiater for public comment. It is tht
Subcommittee's conclusion that the substantive scientific issues raised here should
be addressed before the Agency adopts final guidance. The SAB would like the
opportunity to review the revised guidance and public comments prior to the final
, publication. We are particularly interested that the Agency respond to our
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recommendations for expanding the data set for Tier 2 aquatic life criteria, the
population approach for wildlife, the data requirements for human health Tier 1
and handling multiple carcinogens, the relationship of the GLWQI to other media
within an ecosystematie context, and the Agency's plans for implementation of the
guidance. We appreciate the opportunity to review this important Agency
initiative and look forward to receiving your response.
Sincerely yours,
Dr. Kaymond
Executive Committee
Science Advisory Board
D?, Kenneth L, Dickson, Chair Dr. Verne Ray, Chal
Great Lakes Water Quality Subcommittee Drinking Water Committee
and Ecological Processes and Science Advisory Board
Effects Committee
Science Advisory Board
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NOTICE
This report has-been written as t part of thi activities of the Science
Advisory Board, a public advisory group providing extramural scientific
information and advice to the Administrator and other officials of the
Environmental Protection Agency, The Board is structured to provide a balanced
expert assessment of scientific matters related to problems facing the Agency,
This report has not been reviewed fof approval by the Agency, and hence, the
contents of this report do mot necessarily represent the vie1*? and policies of the
Environmental Protection Agency or other agencies in Federal government.
Mention of trade names or commercial products doss not constitute a ,
recommendation for'use,
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ABSTRACT
The report represents the conclusions and recommendations of the U.S,
Environmental Protection Agency's Science Advisory Board (SAB) regarding &
EPA guidance for the Great Lakes Water Quality Initiative (GLWQI). The SAB
commends the Agency for the interactions among the states, EPA, the private
sector and the scientific community which have lead to the development of this
initiative. The SAB recommended that the introduction to the guidance be revised
to explain the unique characteristics of the Great Lakes and the rationale for an
initiative. The SAB endorsed the ecosystems approach of the initiative and
recommended that it also address non-point sources, atmospheric deposition and '
contaminated sediments. The Subcommittee agreed with the concept of Tier 1 and
Tier 2 criteria but was concerned that the minimal data base currently required in
Tier 2 water quality criterion - a single acute toxieity test • is inadequate. They
were also concerned that the risk management apparatus, currently in place; cf.,
the anti-baeksliding provisions of the Clean Water Act, may prevent adjustments in
Tier 2 numbers when more data become available. The Subcommittee
recommends that the approach to protect wildlife be expanded to consider
ecologically representative species and species sensitivities and to focus on
populations. The current wildlife criteria concepts were formulated around the
perceived requirements of the human health risk assessment paradigm and they
are inadequate for wildlife. The Subcommittee recommended that the program
also consider both the biologically active form and the total contaminants
concentrations when establishing water quality criteria. The GLWQI should
provide some specific guidance on how to handle monitoring compliance for
criteria which are below the detection limits of analytical methods. The
Subcommittee recommended that |he GLWQI add procedures to predict the
persistence of chemicals.
f
The SAB is concerned that the human health risk assessment methodology
being advanced by the GLWQI is not using updated approaches for exposure
assessment and carcinogen classification that are being used by EPA and others,
Tier 1 should be limited to chemicals with good data on carcinogenesis,
reproductive and developmental/teratogenic effects. The linear multistage model
is a reasonable default methodology for chemicals which lack more detailed
information on their modes of action. Ideally, multiple carcinogens should be
considered on a case by case basis, The SAB encouraged EPA to use a variety of
broad criteria to classify chemicals as Tier 2 to encourage improvements in the
data base. The SAB recommended that the draft human health criteria documents
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and guidance for their development be rtyised to reflect SAB eommtats and
improve tilt analysis and presentation of data and rationale for the development of
the criteria.
KET WOKDS: .Wildlife Criteria; Bioacc«nralation; Great Lakts; Water
Criteria, ' • ,
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ILS. ENVIRONMENTAL PROTECTION AGENCY
SCIENCE ADVISORY BOARD
GREAT LAKES WATER QUALITY SUBCOMMITTEE
CHAIR
Dr, Kenneth I* Dieksoii, Institute of Applied Sciences, University of North
Texas, Denton, Texas
M1MBERSA30NSULTANTS
Dr, Anders Andrea, Water Chemistry Program, University of Wisconsin, Madison,'
Wisconsin
Dr. Richard J. Bull* College of Pharmacy, Washington State University, Pullman,
Washington
Dr. Sterling L. Burks, Oklahoma St. University, Water Quality Research Lafa,
Stillwater, Oklahoma
Dr. Lenore S. Clesceii, Rensselaer Polytechnic Institute, Troy, New York
Dr. Peter delHir, Environmental Defense Fund, Washington, DC
Dr. Eolf Hartung, School of Public Health, University of Michigan, Ann Arbor,
Michigan
^*
Dr. Robert J. Huggeit, Virginia Institute of Marine Sciences, School of Marine
Sciences, College of William and Mary, Gloucester Point, Virginia
Dr. Richard Kimerle, Monsanto Corporation, Bt, Louis, Missouri
Dr. Donald Madbay, Dept. of Chemical Engineering and Applied Chemistry,
Institute for Environmental Studies and Department of Pharmacology,
University of Toronto, Toronto, Ontario, Canada
Dr. Ian Nisfaet, ICT Nisbet & Co., Lincoln, Massachusetts
Dr. Dean B. Frexno, White Water Associates, In«,, Amasa, Michigan
Dr. Robert Ringer, Michigan St, University, Institute of Environmental
Toxicology, East Lansing, MI
IV
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Dr. Edward S. Bender, Biologist and Designated Federal Official, Science Advisory
Board, 401 M Street, S.W,» A-101F, Washington, B.C.
Mrs, Marcia K. Jolly, Secretary to ^ the Designated federal Official
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ENVIROHMENTAL PROTECTION AGENCY
SCIENCE ADVISORY BOARD
DfflHKING WATER COMMITTEE
CHME
Dr, Verae A. Bay, Medical Eeseareh Laboratory, Pfizer Inc., Groton,
Connecticut
VICS-CHAIR
Dr. Vein L. SnoeySnjs, Department of Civil Engineering, University of Illinois,
Urbtna, Illinois
MEMBERS/CONSULTANTS
Dr. Richard J» Bull, College of Pharmacy, Washington State University,
Pullman, Washington
Dr, Gory P* Carlson, Department of Pharmacology and Toxicology, School of
Pharmacy, Purdue University, West Lafayette, Indiana
Dr. Keith E. Caros, East Bay Municipal Utility District, Oakland, California
Dr. Lenore S. Clesceri, Eensselaer Polytechnic Institute, Troy, New York
Dr. David G< Kaufman, Department of Pathology, University of North Carolina,.
Chapel Hill, North Carolina
Dr. Samon G. Lee, American Water Works Servici Company, Voorhees, New
Jersey
Dr. Edo D. Pellizzar^ Eesearch Triangle Institute, Beseareh Trianglt Park,
North Carolina
Dr, Mark- D. Sobsey, Department of Environmental Sciences and Engineering,
School of Public Health, University of North Carolina, Chapel Hffl, North
Carolina
Dr. James M. SSymons, Department of Civil and Environmental Engineering,
University of Houston, Houston, Texas
VI
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SCIENCE ADVISORY BOARD STAFF
Mr. A. Robert Flaak, Assistant Staff Director and Acting Designated Federal
Official, Science Advfeoqr Board (A401F), UJ3, EPA, 401 M Street, SW,
Washington, DC 20460
Mrs, Frances Dolby, Staff Secretary, Drinldiig Water Committee, Science
Advisoiy Board (A-101F), U.S. EPA, 401 M Street, SW» Washington, DC
20460
vu.
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TABLE OF CONTENTS
1. EXECUTIVE SUMMARY . , ,' , l
2. INTRODUCTION ,.,.,.,. §
2.1 Statement of the Charge *.*.......... 6
2.2 Subcommittit Review Procedures » , ,, 8
3, AQUATIC LIFE CRITERIA .... 10
3,1 Summary of the Proposed Tier 2 Method *.,..,..,».. .10
3,2 Specific Responses to the Charge .,......,,,,, 'll
3,2.1 Validity of Tier 2 Values 11
3.2.2 Proposed Uses of the Tier 2 Values , 14
3,3 Major Issues Identified Belated to GLWQI Tier 2 Approach 15
3.3.1 Tier 2 and the EPA Advisory Concept 15
3,3.2 Additional Testing . ,- 15
3.3,3 Tier 2 Acute Factors and Acute/Chronic Ratios . 16
3,3.4 Implementation of Tier 2 and Anti*Backslidinf .,,..... 16
3,3,5 Relationship of Tier 2 to Whole Effluent Toxicify , 16
3.3.6 Site-Specific Variability . t 17
3,3.7 Laboratory to Field Validation 17
3,3.8 The WQC Data Base 18
~*
4. WILDLIFE CRITERIA , 19
4.1 Introduction , 19
4.2 Problem and Definition of Significant Terms ..,,,...., 19
4,3 Exposure Assessment , 20
4.4 Dietary and Drinking Water as Routes of Exposure ........... 21
4,5 Use of Rsprtsentative Avian and Mammalian Species 21
4.6 Interpretation of Toxiclty Data , 24
4.6.1 LOAEL vs. NOAEL . * ,, 25
4.6.2 Subehronie to Chronic Extrapolation 26
4.6.3 Field and Laboratory Study Information ,.,,,,, 26
4.6.4 Tissue Residues ,.,,,,.,....,.,,, 27
4.7 Tier 2 , , , 28
4.8 Individual Criteria Documents , . t , 28
4.9 Toxicity Equivalent Factors (TEFs) 29
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5. BIG-ACCUMULATION FACTORS, ,...,,,., . 30
• 5,1 General Comments . 30
5J Field Measured Bioaeeumulation Factors , 30
5.3 Adjusting BCFs to BAFs 32
5,4 BCF for log K^ above 5.0 , ....,..• 34
5.5 Analytical Methodology for Compliaaci »....„.,...... 35
6. HUMAN HEALTH CRITERIA .......».,..' 37
6.1 General Comments .......,,,,,.... 37
6,2 Thresholds for Cardnopns , 38
6.3 Additive Risks for Carcinopns ... ......*.»,.......... 39'
6,4 Tier 1 Minimum Data Baie . ',........».....,.....*...„. 40
6,5 Tier 2 Concept. 41
6,6 Chemical Mutapus ,,,.,.. v. ...'....>..„....., — 41
6,7 Ralative Source Contribution ,.,,,,,,».. 42
6,8 Additional Concerns . 42
Literature Cited , ..., ,.,.... 44
Abbreviations and Definitions ......,,»,,...». 46
IX
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1. EXECUTIVE SUMMARY
The Great Lakes Water Quality Subcommittee of the SAB Ecological
Proctsses and Effects Committee (EPEC) was asked to review the scientific
underpinnings of the proposed Great Lakes Water Quality Initiative (GLWQD.
Thi Subcommittee met February 18-20, 1992 for briefings on the technical
approaches for developing water quality criteria for aquatic life, wildlife, and
human health in the Great Lakes and to receive public comments. This report
summarizes the findings of the Subcommittee which addressed all parts of the
guidance and the recommendations of the Drinking Water Committee which '
focused on the Human Health Criteria (see Chapter 6 of this report).
The Great Lakts Water Quality Initiative (GLWQD is a challenging and
ambitious endeavor. In addition to parties in the United States, Canadian
interests must also become actively involved in developing a consistent approach
for this shared international resource. Based on the materials reviewed and the
presentations to both Panels, it is evident that a great deal of time and effort has
been spent by all parties. The SAB encourages the continuation of interactions
among the states, EPA, the private sector and the scientific community in furthtr
developing environmental protection programs for the Great Lakes.
The SAB recommends that the introduction to the documents be revised to
explain how the Great Lakes are unique in terms of their water quality problems
and issues, and indicate how the unique aspects of contaminant exposure of the
biota in the Great Lakes dictate the approach being advanced, A better rationale
should be developed and presented in the guidance documents on why a Great
Likes specific approach for establishing water quality criteria for aquatic life,
wildlife and humans is needed. Inclusion of data showing trends in the levels of
contaminants in the Great Lakes and t history of contaminant related ecological
problems and issues associated with the Great Lakes would be of value to place
the proposed program in perspective.
The GLWQI makes an effort to ust an ecosystem approach to environ-
mental protection. The Subcommittee strongly endorses an ecosystems approach
because it is more scientifically sound than thi piece-meal approach that has been
historically used, The approach should also take into account the sources, sinks,
and transport routes of these chemicals. The great opportunity of an ecosystem
approach is to capture the major inputs and* target resources for the most effective
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control measures;,, Jt Is not clear however, what specific .mechanisms the GLWQI
has incorporated to address non-point sources, atmospheric deposition and
contaminated sediments. The current approach is specifically directed at point
sources effects on water quality and biota, A complete ecosystem approach should
examine all sources of contaminant loadings, all ecosystem compartments and all
ecological receptors, While the SAB recognizes that this is difficult, .the position of
the GLWQI in an overall ecosystem approach for environmental protection of the
Great Lakes should be identified.
A fundamental aspect of the Great Lakes Water Quality Initiative Is the
principle of using Tier 1 and Tier 2 data in developing water quality protective of -
aquatic life, wildlife and humans, The Subcommittee agrees in concept with this
approach. There are many chemicals for which Tier I data do not exist, yet which
need regulation, A Tier 2 approach, if properly applied, provides a mechanism for
controlling those chemicals for which there are limited scientific data while at the
same time provides a mechanism for reducing uncertainty regarding then-
environmental consequences, The Subcommittee is concerned that the
data base currently required in Tier 2 - a single acute tesacliy test - is inadequate.
The Subcommittee recommended that the Tier 2 minimum data base include
estimates of chronic toxicity and matrix effects in tozicity,
The BAB fully expects that as additional scientific data accumulate, the
technically derived values for WQC will change in response to new information. It
is not clear, however, that the risk management apparatus currently in place is
capable of accommodating these scientific' improvements; cf., the .anti-backsUdimg
provisions of th§ Clean Water Act. The Board is concerned that situations could
arise in which risk management positions are not scientifically defensible.
The Subcommittee supports the GLWQFs efforts to develop an approach to
protect wildlife from the effects of bioaccumulative chemicals in the environment,
However, the Subcommittee is concerned that the current approach does not
adequately consider ecologically representative species in selection of surrogate
wildlife species. Similarly, the Subcommittee feels that the definition of wildlife is
ambiguous as used in the GLWQI. We recommend that EPA and the GLWQI
develop a definition of wildlife and justify species inclusions and exclusions.
Begardless of the definition, provisions should be provided in the GLWQI for re-
evaluating and updating the list of surrogate ^pecies. In addition^ the exposure
assessment needs to be differentiated between species sensitivities and effects of
the chemicals,
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The Subcommittee is also concerned that the methodology- used in the
GLWQI to assess the range of species sensitivities netds further development. In
contrast to tinman health criteria,which are designed to protect individuals,
wildlife criteria are designed to protect populations and must consider differences
in species sensitivities. This aspect is not a part of the human health methodology
which has been applied to establish wildlife criteria in the GLWQI. The
discussions of the Lowest Observed Acute Effect Level (LOAEL) versus the No
Observed Acute Effect Level (NOAEL) in the Technical Support Document are
vtry superficial. These concepts were formulated around the perceived
requirements of the human health risk assessment paradigm. While they may be
applicable to human health risk assessment, they cannot serve as foundations for -
tht development of criteria methodologies for the protection of wildlife. Further'
explanation is needed of how the two applications differ and how they wM be
addressed. Tht GLWQI should develop guidance for the selection of NQAELs
appropriate for the protection of local and regional wildlife populations as distinct
from the protection of individuals,
There are a number of regulatory approaches which have direct bearing on
chemical, physical and biological water quality and protection of aquatic Hfe,
wildlife and humans. The relationship of these approaches to the GLWQI is
unclear and was not adequately addressed in the materials examined by the
Subcommittee. What is the relationship of the proposed GLWQI to whole effluent
biomonltoriag? How does the GLWQI focus on bioaccumulative chemicals relate to
the HPLC based screening approaches for bioaeeumwlativt chemicals in effluents?
What is the interface between the GLWQI and the National Sediment Quality
program? It is not clear from the documents reviewed and the presentations that
these techniques and activities were considered in developing the GLWQI
approaches.
The GLWQI is designed to establish water quality criteria Jfor total
contaminant concentration not the bioavailable form of the contaminant. The
Subcommittee recommends that the program also consider the biologically active
form of contaminants when establishing water quality criteria. The Subcommittee
feels that by basing the water quality criteria only on total concentration that
much of the science which has developed in the last ten years on the importance
of chemical speciation and biological activity is being ignored. The approach is
also inconsistent with the one for sediment criteria which uses the soluble forms
of contaminants, but not the total concentration.
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Since a water quality criterion for. a chemical may.be the result of a back
calculation from a measured or predicted biological residue concentration and/or
•based on Tier 2 data, the appropriately calculated water concentration taay be
several orders of magnitude below detection limits of eurrtntly accepted analytical
methods. This creates a serious compliance monitoring problem and may further
widen the credibility gap between the regulatory agencies, regulated community
and the public. The GLWQI should provide some specific guidance on how to
handle this problem.
The Subcommittee notes that the GLWQI appears to have no elements
which predict the persistence of chemicals. The proposed approaches also do not *
consider rates of oxidation, hydrolysis, volatilization, sorption and all of the
environmental transport and fate pathways. The approach for assessing
bioaeeumulation factors (BAF) advanced in the GLWQI uses oefanol/water
partition coefficients (Log P) and food chain models to predict residues in biota,
While these approaches appear to have some utiliiy, there,are alternative
"approaches (Lebo et al, 1992 and Johnson, 1091) which should also be explored as
part of the GLWQI such as using biological residues, partitioning methods with
C18 and/or Tenax tad "artificial fish".
The SAB is concerned that the human health risk assessment methodology
being advanced by the GLWQI is not using updated approaches for exposure
assessment and carcinogen classification that are being used by EPA and others.
Tier 1 should be limited to chemicals with good data on carctoogeaesis,
reproductive and developtnental/teratogenie effects. Tier 2 should contain
chemicals for which a less complete data set existsvand. appropriate uncertainty
factors are incorporated to compensate for this lack of data. The Agency must
move forward by using biologically based models for assessing carcinogenic risks at
low doses. The linear multistage model is,a:reasonable default methodology, but
the Agency appears reluctant to follow its own guidelines when appropriate
mechanistic, pharmacokinetic, or other relevant data are available for Individual
chemicals, Ideally multiple carcinogens should be considered on a. case by case
basis, because the assumption of additivity has both practical and scientific •
shortcomings. The SAB recommends that the draft human health criteria
documents and guidance for their development be revised to reflect SAB comments
and improve the analysis and presentation of data and rationale for the
development of the criteria.
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2. INTRODUCTION
The Great Lakes Water Quality Initiative (GLWQI) was developed by the
U.S. EPA in cooperation with the states in the Great Lakes Basin to ensure
consistency in the development of water quality standards to maintain, protect,
and restore the unique Great Lakes resource, EPA Region 5 (Chicago, IL) has
taken the lead role since the effort began in 1989. The schedule for GLWQI
activities, under the Great Lakes Critical Programs Act, required EPA to publish
final GLWQI guidance.by June 1992 and for Great Lakes States to adopt the
guidance as part of their state water quality standards within two years of the '<•
publication of final guidance,
The GLWQI consists of six interconnected procedures: a) derivation of
criteria for the protection of aquatic life; b) bioaeeumulation factors; e) derivation
of criteria for the protection of wildlife; d) derivation of criteria for the protection
of human health; e) protection of current water quality (antidegradation); and f)
translation of standards into regulatory controls (implementation). This guidance
was developed by technical work groups of scientists from the states, U.S. EPA,
U.S. Fish and Wildlife Service, and the U.S, National Park Service with input
from a public participation group which includes members of the regulated
community and academia. As a result the GLWQI is being developed and
implemented through an iterative process and has a goal of being based on a
broad consensus.
The GLWQI guidance is being developed primarily from the water quality
perspective and it will be implemented through the National Pollutant Discharge
Elimination System (NPDES) permit program. As a result, it draws heavily from
the Agency's technical guidance and experience with water quality criteria and
surface water monitoring, States rely on the water quality criteria as the
foundation of their state water quality standards.
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2.1 Statement, of the Charfe
On January 8, 1992, Mr, Dale Bryson, Director, Water Division, EPA Eegioa
5, sent a revised charge to the Science Advisory Board (SAB) requesting a review
of the recommendations of the EPA-State Great Lakes Watt? Quality initiative.
In particular, he asked that the SAB focus on questions related to four guidance
documents; Aquatic Life; Bioaccmmilation Factors; Wildlife Methodology; and
Human Health,
Specific aspects of the charge were:
A Tier 2 Aquatic Life. Proposal
1} Does the Tier 2 methodology provide a valid method for
developing values in the absence of sufficient data to meet the
Tier 1 requirements?
2} Is the derivation of the values compatible with the proposed.
uses of the Tier 2 values?
B. SMJfejCrJtgrfa Methodology
1) Is the •wildlife' criteria algorithm, which only considers dietary
and drinking water exposures reasonable?-*
2} Are the representative avia^. and, mammalian species reasonable
and appropriate lelectionst
3) Is .the pneral approach for usmg_«ncertaini^ acceptable? Is
the derivation of those factors adequately explained?
* * * "* \
43 With regard to the four wildlife criteria calculated for Mercury,
DDT, Diosin, and PCBs, are the toxieily data reviewed
complete and their subsequent mtei^M^fcation appropriate?
5) ' Are the TEPs [toxicity equivalent factors] chosen for diosms,
coplanar and monortho coplanar PCBs acceptable and is their
application in deriving criteria adequately presented?
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C, BioaecmmilatioB Factors (BAF)
1) Is the BAF/BCF tBioeoneentration Factors] for organic
chemicals usefully related to the percent' Mpid to tissues?
2) Are field measured BAFs suitable for the calculation of
generally applicable criteria?
'3) Is a BCF an underestimate of a BAF for organic chemicals with
log K^ In the rangt of 4.5 to 6.5?
t
4) Is the proposal to adjust BOFs to BAFsf based on Thomson
(1989) appropriate?
5) Are there chemicals or groups of chemicals (e.g., PAHs?) with
log KQW in the 4,5-6,5 range for which the application of a food
chain multiplier is not appropriate?
0, Human Health Criteria
1) Is the Linearized Multistage Model appropriate to manage
chemical carcinogens?
2) Should additive risk be considered in evaluating ambient water
quality of the Great Lakes? If so, how should this be
presented?
3) Is the proposed minimum data set for Tier 1 appropriate for
establishing region wide numeric water quality criteria? Is it
appropriate to treat A and B level carcinogens and certain
designated C level carcinogens equally via this approach?
4) Is it defensible to regulate environmental contaminants via the
proposed Tier 2 approach? If so, what is the minimum
database necessary? la it scientifically defensible to manage 0
level carcinogens via this Concept?
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55, Is the approach to identify chemical ttitttagens and teratogens
for special .consideration appropriate? If so, how should they
be controlled?
6) Is the concept of relative source contribution a scientifically
valid approach in controlling- the significance of this route in -
total food chain and other exposure to bioaccumulstive
contaminants?
The Subcommittee accepted this charge, but also requested further
information on the use and rationale for these procedures and clarification of ', '
certain regulatory definitions that would affect these concepts, The Subcommittee
agreed that the human health criteria, guidance would also be reviewed by the
DrinMng Water Committee of the SAB and the application of TEFs wouM be
reviewed by the SAB's Dioxin Eeotox Subcommittee. •
2.2 Subcommittee Review Procedures
The Ecological Processes and Effects Committee (EPEC) of the SAB was
assigned the lead for coordinating the review of the GLWQI technical guidance.
The Great Lakes Water Quality Subcommittee was composed of members and
consultants from EPEC with expertise to address the four areas of the charge
from the perspective of surface water quality. Two members of the DrinMng
Water Committee provided additional expertise on human health criteria and
human cancer risk assessment methodologies to the Subcommittee. In addition,
the Drinking Water Committee, including t consultant-from EPEC, separately
reviewed the Human Health Criteria guidance. :-
The Great Lakes Water Quality Subcommittee (GLWQS) met in Hoseniont>
Illinois on February 18*20, 1092 toreceive1" briefings on the technical guidance and
take public continents, The Chairman summarized the preliminary impressions of
the Subcommittee on the overall initiative. He also explained that other panels of
the SAB would address portions of the charge. At the meeting, the Chairman
asked EPA to provide the Subcommittee with further information regarding
implementation of the guidance (January 1992 .version of the gederal Register
preamble to the guidance), the goals of the program and its relationships to other
media, the reasons for a unique approach, in the Great Lakes Basin, and the
process for monitoring compliance of criteria that are below analytical levels of
detection. The GLWQI provided the Subcommittee with copies of the draft
8
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preamble (dated, January, 1992), implementation guidance (created December,
1991), and other documents to address these issues. In addition, the
Subcommittee received written comments from 16 parties and heard oral
comments at the meeting. In May 1992, the Subcommittee 'held a writing session.
The Drinking Water Committee met on April 14 tad June 1, 1992 to review
the guidance for human health criteria. Copies of comments from the GLWQS
were provided to that group and three members of the GLWQ Subcommittee were
present for the discussion. The comments of the DWC appear primarily in
Chapter 6 of this report.
The Subcommittee also received input from the SAB's Dioacin
Subcommittee of EPEC which reviewed a question related to Toxiclty Equivalent
Factors (TEFs). The Subcommittee noted that the use of TEFs would be
addressed by the SAB's Environmental Health Committee (EHC) as part of the
revaluation Of the Agency's Dioxili Bisk Assessment, therefore, the comments
"hire and in the Dioxin Ecotox review (Science Advisory Board, 1992) were limited
to specific research needs on TEFs for wildlife and aquatic life.
9
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3. AQUATIC OF!
3.1 Summary of the Proposed Tier 2 Method
A two tiered procedure to derive aquatic lift water quality criteria Is being
proposed in .the Great Lakes Water Quality Initiative for the protection of aquatic
life from exposure to individual chemicals contained in point source effluent
•discharges to the Great Lakes,
Tier 1 acute and chronic numeric criteria will be derived using a *
modification of the current U. S. Environmental Protection Agency's "GhiidfiJines
for Deriving Numerical National Water Qualify Criteria for the Protection of
Aquatic Organisms and Their Uses." Great Irakis Basin States tre ejected to
adopt these as numeric criteria. 'Major modifications of'the original EPA
guidelines included the following: deletion of saltwater criteria, final residue value,
and considerations related to'wildlife species; and inclusion of lower criteria to
protect commercially or rteraationally important species In the Great Lakes Basin,
use of Ceriodaphnia f*day life cycle test in the criteria, and the use of the two
tiered approach when sufficiently large data bases art not available.
The Tier 2 approach is structured in a manner conceptually similar to the
U.S. EPA water quality criteria method. A statistical procedure was applied to the
"universe11 of data existing within the EPA water quality "data base. Instead of the
Tier 1 requirement of a minimum base of-acute toxieity
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not adequate to- meet the Tier 1 data base requirements. GLWQI anticipates the
Tier 2 criteria concentrations will be more stringent, Li. over-protective, than the
Titr 1 criteria, Host tt al. (1990), developers of the statistical approach advanced
for Tier 2, intended the Titr 2 values to be used as narrative standards and not to
be used for numerical criteria.
The existing data bast for Tier 1 chemicals was subjected to a statistical
analysis to determine the effect upon the calculated Final Acute Value (FAV), if
portions of the toxicity data was sequentially removed. This data set was then
subjected to a probability analysis to determine if a Secondary Acute Value (SAV)
was calculated according to Tier 2 protocol if there were a sequential reduction ia "
the number of acute toxic% values available, Le., from 8 to 7, 7 to 6, ...» 2 to 1.
The resulting data sets were then analyzed to determine the percent frequency
when the Tier 2 SAV would be less than the Tier 1 FAV. The choice of the
percent probability used to choose the secondary acute value, Le., 80% was based
upon the assumption that the probability of the Tier 2 SAV would exceed the FAV
only 20% of the time, (The Subcommittee is not aware of any rationale provided
in the documentation for this particular value.) The ratio of FAV/SAV was
calculated to be 3.6, which was labeled the "Final Acute Value Factor*' (FAVF),
This FAVF is utili2ed to calculate a SAV by dividing tht lowest genus (Daphnid
species) mean acute value (GMAV) by the FAVF; SAV o (lowest GMAV)/FAVF.
The final standard, "Secondary Chronic Value" (SCV) is then calculated using the
SAV divided by the Secondary Acute Chronic Eatio (SACR), which is derived from
the ordered ratio's of the Tier 1 data set FAV/FACS, The S&Vs were ordered
from high to low so that a secondary acute-chronic ratio could be derived to
correspond to any selected percentile,
3 J2 Specific Responses to the Charge
3.2.1 Validity of Tier 2 Values
The intent of developing a Tier 2 protocol was to supplement the acute
toxicity database, and produce values to be adopted as narrative standards, The
Tier 2 numbers were designed to provide a:
a) basis for evaluating potential for concern,
b) focus on chemicals which need more toxicity data,
c) basis for regulatory limits under some circumstances.
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The Subcommittee indorses the. original intent of using Tier 2 numbers to
identify those contaminants of concern which need additional toxicity data.
However, the Subcommittee is concerned that Tier 2 values might be adopted as
regulatory limits for point source dischargers. The Tier'2 numbers were designed
to be over protective in the arbitrary choices of percentage distributions from the
original data set* These numbers should only be used as interim narrative
standards not as nmnerie Mmits, Otherwise»EPA may be forced to revise it's
policy on anti-backslldlng (see footnote 1 on page 14 a»d Section 8*3,4).
Under the best of circumstances water qualify criteria developed using the
national guideline approach are generated from data which contain significant . ,
uncertainties. For example, the statistical variances associated -with the generation
of EC and LCSO's are not included in the dematioiL The procedures used in
.developing the Great Lakes Initiative (Gil) aquatic criteria are based in large part
on the national criteria, i.e., an assumption has to have been made that the
national criteria are correct and therefore can be modified for use with
significantly smaller data sets. This may in fact he true, although it is probably
also true that the smaller the data set the greater the uncertainty. EPA
recognizes this and the acute factors which have been generated reflect tills (Table
D.
Table I :
""I.
Relationship Between Data Requirements and Uncertainty
Number of Minimum Data
.Requirements
1 , . . .
' . 2. .
3
'4
5
6
. 7
Acute
, , ,, , ..Factor .
20 ,
...,:- ,-13 ;{ji-
8 J '
6.5
5,0
4.0
3.6
There are at least two features that are disconcerting about this approach.
The example which follows will be used to describe one of these.
12
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The data on which the national water quality criterion for copper was
developed includes numerous tests for which the test species was £ magnti,
The LC/EC50 values for this species range from 10 ug/L to 200 ug/L. If the
procedures for the GLI wtrt followed and the only date that were available
for copper were the EC50 of 200 ugflu, then the Secondary Acute Value
would be:
Secondary Acute = lowest: GMAV
Value Acute Factor
= 200jig/L = 10 ug/L v
20
If on the other hand the only data available for copper were the EC50 value
of 10 ug/L, then the Secondary Acute Value would be:
Secondary Acute **
Value Acute Factor
= .10 u£& - 0.5 ug/L
20
These data suggest that for those chemicals for which there is a significant
matrix effect, significant differences in the secondary maximum concentrations and
also the secondary continuous concentration can exist if only a single GMAV is
available for evaluation. An alternative approach, might be to dictate not only the
species to be tested but also the matrix, although the number of matrix factors
altering bioavailabillty can be extensive.
The iecond factor of concern about this approach is the relationship
between data generation and cost. It has been suggested that fcht costs of
generating a complete data git for deriving a National Water Quality Criteria
could be a much as $100,000 per chemical. However, there has to be a gradient
for costs between generating a single acute value tnd complete data set. If short
term chronic test results are acceptable for input into the derivation of the Great
Lakes criteria then tests could be undertaken for less than $5,000 per chemical for
two matrices and two species of test organisms.
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The Subcommittee is concerned that the minimal data base of one species
acute test is inadequate. From a statistical perspective, the historical data base is
probably scientifically defensible to account for many of the sources of toxieologleal
testing uncertainty. However, a purely statistical analysis "of the existing historical
water quality data base does not reflect several important contemporary
considerations. Although' acute toxicity data can be very useful whea there is a
void of other data, the current state-of-the-science is to rely upon data that are
more characteristic of chrome effects. Some new fairly inexpensive short cut
methods with some plants, invertebrates, and fishes offers many advantages over
acute data with extrapolations to chronic effects of other species. The Mayer
method of the "infinite LC Zero" should be considered as an alternative to just -, -
using single acute data.. Another important consideration is the effect that the
characteristics of the water can have on toxicity. In the case of metals, softer "
water makes the chemical more tojdc and turbidity mitigates the toxiefly of
lipophilic organic chemicals. These matters are not easy to include in a regulatory
program, However, the Subcommittee challenges the Agency to mate better use of
' current science,, Defaulting to the statistical derived estimates with limited
consideration for the complexity of water qualify factors may not be serving the
best interest of water quality.
3J,2 Proposed Uses of the Tier 2 Values
The Subcommittee believes that Tier 2 values are compatible with the
proposed uses, if used as a -'value" and in a manner consistent with guidance very
appropriately spelled out in the introduction of the EPA document (Host et aL,
1990). The briefing of the Subcommittee by GLWQI personnel in February 1992,
clearly indicated in the handouts the concept "Tier 1 numbers were to be adopted
by Great Lakes states as numeric criteria" and Tier 2 "to be adopted as a
narrative procedure". However, the Subcommittee,is concerned about how Tier 2
will be implemented, particularly with respect to such issues as permits, permit
limits, periods of time allowed for improving the data base, and anti-backsliding1.
AfltPHNrkfIMIflg U A 10gaJ Concept from the *^**^ Wa*ftr Aft yWM* pTohib*** ***•
EPA imj^ tllow fit&& Tfl^ffirajfoB'p HTt^ftn cftftaifl eipetimjfra*^**^ wfcifl^ iaay fc^lffife $faA ^f^t^BTT 9* spw
wtush Indicate that tbt und«rlyiii5 criteria are too stnagenV Modification of permit «">&• may «Uo bt affected 1^
previatow of >tftt« w fwkrai 2aw,
14
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SJ Major Issues Identified Related to GLWQI Tier 2 Approach
3.3.1 Tier 2 and the EPA Advisory Concept
The proposed GLWQI Tier 2 method is similar at least in its intent to the
Michigan Suit 57 and the U.S. EFA's "Guidelines for Preparing Water Quality
Adviiories" developed several years igo. In a 1988 review of these guidelines for
advisories, the Environmental Effects, Transport and Pate Committee of the SAB
endorsed the aquatic life advisory concept while recognizing that advisories should
not be a substitute for continuing development of water quality criteria based on a
full set of data (Science Advisory Board, 1988), In addition, the Subcommittee V *
identified several issues that needed to be addressed in order to enhance the
potential utility of the approach. These included: the problem of implementation
where laws stipulate that state water quality standards cannot be made less
stringent, as would be the case as new data ultimately lead to a full water qualify
criteria; a method to identify which chemicals deserved advisories; better
documentation of the uncertainty factors used; input data quality, inclusion of the
concept of exposure duration; and site specific modification possibilities,
In this review of the Tier 2 method, which was judged similar in intent and
use to the previous water quality advisory method, the SAB Subcommittee once
again endorsed the concept recognizing that many of the scientific deficiencies
identified in thi previous method may have bttn addressed in the new statistical
procedure. However, most of the science-related policy and Implementation issues
cited in the previous review are relevant,
3.3,2 Additional Testing
The Subcommittee noted that the second'paragraph on page 1 of the
"Analysis of Acute and Chronic Data for Aquatic Life" that EPA realizes that
"although a criterion (full Tier 1)) might be desirable, it might not be necessary*.
EPA further discussed how the Tier 2 data can bt appropriately used to determine
whether a predicted or measured exposure concentration of a chemical in a body
of water is cause for concern because of toxicity to aquatic organisms. If the
margin of safety is sufficiently large Tier 2 data may be adequate without any
additional data. If the margin is small then there may be a justification to expect
additional toxleity testing in order to get better resolution on the safety issue. It
was recognized that this Tier 2 approach would help avoid the generation of
unneeded data,. The Subcommittee feels that this is a good use of the Tier 2
-------
approach and reec-mmeiads its use in this manner. However, Tier 2 values should
not replace the more scientifically defeasible Tier 1 criteria,
3.3 J Tier 2 Acute Factors and Acute/Chronic Ratios
It was not possible for the members of this Subcommittee to judge the
absolute validity of the statistical analysis of acute and chronic data. However,
the method seemed conceptually correct hut could benefit from a review by a
separate group of experts in statistics. Many of the concerns expressed ID the
previous SAB review on tht guidelines to derive water quality advisories appeared
to he addressed with this new statistical method. However, the Subcommittee stJJT
cautions against misuse of the Tier 2 concept and specific values derived from the
procedure.
3,3.4 Implementation of Tier 2 and AntE-Backsh'ding
The Subcommittee expressed concern on the issue of how the Tier 2 data
might be used by some states and the implications of the current EPA policy of
anti-bacfcslidtng. States implementing this Tier 2 method must realize that all
Tier 2 estimates will, because of the statistical derivation method used, result in a
value more stringent than a full criterion. As moire data are obtained over time,
the value will frequently become, less stringent as it approaches the Tier 1 value.
If these facts can not be dealt with in implementation then there can be no
scientific defensibility in the Tier 2 concept
3.3,5 Relationship of Tier 2 to Whole Effluent Toadcity
EPA recognized years ago the water quality criterion program (Tier 1) of
the NPDES was not addressing all the- needs ia-protecting-the nation's water.
Thus, the whole effluent toxieity; testing propam was. developed-and implemented
to regulate the many unknown chemicals that- were likely to cause adverse impacts
in receiving waters, This whole effluent tokicity testing program is recognized by
the Subcommittee1 as a valuable and scientifically justifiable program. It is
lomewhat redundant with the intentions-of the- GLI Tier 2 aquatic life criteria
approach. The Subcommittee believes that if thf Tier 2 program is implemented
within the framework of the previous discussion on "guidance and anti-backsliding*
then it can be a valuable additional tool in the hands of the water quality
manager, It would he unfortunate if the Tier 2 method was used to generate
16
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useless and unseeded information on long lists of chemicals; whole elHutnt toxieitf
testing should bt included as an alternative*
The Subcommittee recommends that the GLWQJ consider incorporating
many of the practices.and policies embodied in the "Whole Effluent Toadciiy Tests"
program, An "in-situ" fish or mussel bioaccumulation test Of an HPLC test could
be implemented, as part of a battery of tests, to alleviate the concerns of
establishing limits based upon calculated bioaccumulation factors (BAF's) that may
be either too stringent or inadequate to achieve the desired levels of protection,
The Subcommittee accepts the concept that a "field1* measured residue of ~f -
nonpolax contaminant relative to the mean "bioavailable" concentration in the
water should be acceptable measure of BAF. Even this measure Is subject to
considerable error due to temporal changes in concentration of the contaminant,
analytical errors associated with dissolved versus sorbed fractions,, and uptake
rates by individual fish. Also, the exposure time should" be* sufficient to allow for
development of equilibrium conditions between the contaminant in tht
environment and the organism.
3JJ Site-Specific Variability
Criteria derived from tht Tier 2 minimum species data set may not
adequately consider site specific factors such as water hardness and warm versus
cold water conditions. Application of such calculated values 'could result in
unknown over- or under-estimation of the concentration needed to protect aquatic
life* This can occur because fewer species tested under fewer water quality
conditions can result in criteria with limited application over the rangt of water
temperatures and hardness conditions of the Great Lakes Basin. "
3.8.7 Laboratory to Field VaUdatioii "
A need was recognized to review the protjctiveness of these Tier 2 values in
relation to real world impacts. The Subcommittee suggests that some of the
existing field studies that have analyzed Tier 1WQC for their application could be
revisited with the intention of looking at the degree tff conservatism that will
result from Tier 2 values, '
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3,3.8 The WQC Date Base
The overall process of combining the acute and chronic toxieity data for the
set of 29 chemical contaminants may have introduced artifacts when comparing
toxic effects of metals, insecticides, solvents, petroleum hydrocarbons, etc. The
mechanism of action of the different classes of coataminajits could certainly
influence the ratio of acute to chronic toxieity values. Thus, limits derived from
the grouped contaminants could be either over* or under-protective of aquatic life
exposed to a specific contaminant, All data were put into a single data set to
increase the size of the database. Chemical effects data were not separated
according to modes of action or obvious classes such as metal, pesticides, and ', "
others, It would have been more scientifically sound if this had been done,
especially for the acute to chronic ratio. However, the reduced size of the data
base would have reduced the robustness of the statistical parameters. As more
data are accumulated over time, EPA should split the data as suggested to
improve the quality of the estimates.
18
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4. WHDLIF1 CRTEEBI&
41 Introduction
The development of criteria for protection of wildlife is probably the most
innovative aspect of the Great lakes Initiative. The lack of suck criteria lias been
a significant obstacle for the Agency 'with respect to its overall mission of
protection of the environment. Although the Subcommittee lias major reservations
on the scientific defensibility of certain aspects of the present formulations of the
wildlife criteria methodology and specific aspects of the proposed criteria, the ~r
Subcommittee wishes to encourage and' support the Agency's efforts in the
development of criteria,for protection of wildlife. It should also be noted that
habitat and disease may have major influences on the success of local populations
of wildlife,
The development of methodologies for the criteria to-protect human health
and aquatic life has required considerable effort The experience gained in
developing these methodologies gives tht developers of the methodologies for the
derivation of criteria for the protection of wildlife a considerable head start
However* this does not imply that wildlife criteria can be generated througa minor
fine-tuning of existing criteria, or that the existing data base is adequate to
generate criteria for all substances of concern without the need for further
research.
42 Problem and Definition of Significant Terms
What is the definition of wildlife in the context of the criteria? Does the
term refer to all animal sptcies that are not domesticated, or does it refer only to
air-breathing vertebrate species that are legally hunted, does it include
invertebrates, or is it some intermediate definition? -In the Great Lakes, Initiative
wildlife appears to have been defined in terms of & restricted number of
piscivorous species: otters, mink, bald eagle, osprey, and kingfisher. These species
occupy the apices of the water based food webs in the Great Lakes and would thus
be expected to be highly exposed, The draft should explain that tht representative
species are not intended to be the most sensitive specks exposed to the chemicals,
Alternatively, the recent National Wildlife Criteria Methodologies meeting of tht
U.S. EPA in Chariottesville, Virginia (April 13 -16,1992) defined wildlife as
mammals, birds, reptiles and amphibians. It is acknowledged that there is a body
19
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of knowledge on the experimental biology of some amphibians which would permit
the development of a lexicological data base in short order. However, in spite of
this laboratory capability for studies in amphibians, such & toxicologies! data base
has not been assembled, Beyond this, the basic knowledge on the natural history
of reptiles is so fragmentary that it is not possible to maintain tiiem routinely in
the laboratory over a complete life cycle. Consequently it is not even possible to
establish & toxicological data base covering fall life cycles for representative
reptiles at this time. Although the definition of wildlife given at the National
Wildlife Criteria Methodologies meeting is broad, and even though tht taaeological
data base to support it is fragmentary, the broad definition of wildlife is more
supportable than the limited list of species used by tht Great Lakes Initiative. »
Several important questions exist regarding the establishment of wildlife
criteria. Should there be national criteria, regional criteria, aquatic wildlife
criteria, or species specific criteria? Should the methods be developed in such a
way that they are suitable for the development of criteria at either the national
ievf 1, or at site specific levels, or at organism specific levels? If the methodology Is
properly constructed, it may be feasible to fulfill all of these roles. In light of
these concerns the Subcommittee recommends that the Agency develop a general
definition of "wildlife" and justify inclusions and exclusions of particular groups of
4.3 Exposure Assessment
The Great Lakes are unique in their considerable geographical extent and
the long residence times of water and persistent contaminants within the lakes*
This aspect of the Great Lakts requires an understanding of the environmental
transport and fate of the contaminants, and developing a basin-wide approach to
their control, Fish and wildlife in the Great Lakes (and elsewhere) exhibit high
body burdens of substances that tend to bioaccumulate. For some substances
(DDT, dieidrin, PCBs) the body burdens in the recent past have eiceeded those of
today. High body burdens of some contaminants have been associated with
adverse effects in field studies, although it remains controversial whether these
associations are causally related. EPA has appropriately identified bloaceunmlative
chemicals and potential effects on wildlife as major issues of concern. However,
little foundation was presented to indicate that the Great Lakes system is unique
with respect to either how chemicals bioaeeumulate or the inherent sensitivity of
the species that reside in the Great Lakes basin and how their populations art
exposed and at what level they will be protected.
20
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4.4 Dietary and IMoMng Water as Routes of Exposure . ,
At present the exposure assessments for wildlife are based primarily upon
bioeoneentrated substances IE foods plus direct uptakes of substances from
drinking water. Given the emphasis on chemicals with high BAFs, the influence
of the drinking water route of exposure Is negligible for those specific chemicals.
Furthermore, in the present Great Lakes Initiative, wildlife exposures via
inhalation or dermal contact are not considered. These routes of exposure can
become important for .chemicals with significant vapor pressure and intermediate
molecular weights,
Overall, tht proposed wildlife criteria methodology is confounded by
combining exposure assessments (in terms of the BAF) with risk assessments (in
terms of assessments of dose-response relationships extrapolated to daily intakes
that do not produce adverse effects). If the Great Lakes Initiative's intent is to
protect populations of wildlife, then it is important to control the daily absorbed
dose of the chemical of concern to the members of the population of that species,
regardless of the route of exposure. The BAF issue is significant, it needs to be
explored on its own merits, but it should not confound the risk assessments in the
development of criteria for the protection of wildlife.
4.5 Use of Representative Avian and Mammalian Species
Many species of mammals, birds, reptiles and amphibians are subject to
substantial exposure to w&terborne contaminants in the Great Lakes basin. An
initial listing of all these species, with basic information on size, diet, and foraging
zone, would show that the five piscivorous species considered in the document axe
not representative of the fuU range of any of these three characteristics.
Additional species subject to substantial exposure include the raccoon, horned
grebe, double-crested cormorant, green-backed heron, old squaw, black tern,
common tern, Forester's tern, piping plover, tree swallow,' snapping turtle and
northern banded water snake. It is not self-evident that these species are ^pres-
ented" by any of the five piscivorous species considered in the present document.
In conclusion, the Subcommittee is -concerned that the current approach does not
adequately consider ecologically representative, species in the selection of surrogate
wildlife species. The Subcommittee recommends that if the agency chooses to
address, a specified list of species, then that list should be re-evaluated regularly
and a rationale provided to add particular species,
21
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Most of the proposed methodology for wildlife criteria is devoted to methods
that estimate exposures. It is possible to estimate (with uncertainty) the total
daily intake of a contaminant by an individual by estimating bioaccumulation in
the food web, proportions of food arising from various trophic levels within that
food web, daily food intake on the basis of allometric equations, and estimating
the uptakes from other routes of exposure (inhalation and dermal). However, the
methods do not consider the exposures from all environmental media. In addition,
the estimates of daily intake are species and life-stage specific, they do not
adequately address the question of the extent to which one species may be more
sensitive than another, given the same amount of daily exposure, These
differences in species sensitivities are currently addressed by the application of &f -
Species Sensitivity Factor (SSF) which can vary from 0.1 to 1 (see later discussion
on page 24).
The proposed GLWQI wildlife methodology is basically a modification of the
methods to derive risk assessments on human health for substances that exhibit
thresholds for non-cancer toxicologies! effects. Risk assessments for the protection
of human health use information generated during the studies of several species to
draw conclusions with respect to a single species * namely humans. Unless there
is information to the contrary, it is assumed that humans are at least as sensitive
as the most sensitive test in the most sensitive species tested. Furthermore, risk
assessments for the protection of humans seek to protect the individual against
effects which may be subtle, effects which relate to the quality of life rather than
survival, and effects which may only occur in sensitive sub-groups and occur over
long periods. Therefore, the tests that are incorporated into protocols applicable
to developing criteria for the protection of human health can be very sensitive,
and often go beyond the basic needs for protection of a species to assure the
maintenance of its local population level. In contrast, criteria for the protection of
wildlife must make allowances for differences in species sensitivities thtt are not
incorporated into the methodology that has been developed for the protection of
human health. When one seeks to protect a broad range of wildlife species, the
challenge is to extrapolate from experimental data developed within a very limited
group of laboratory species to the potential effects that may occur in the broad
range of species whose populations need to be protected in the environment. This
is complicated because the range of species sensitivities is not "a constant, and the
range of species sensitivities cannot be adequately captured in the allometric
equations, which are largely related to species differences in dietary intake and
body size. Independently of body sisje and dietary intake, the range of species
sensitivities can be very narrow (e.g., with HGN or CO), or it can be very large
22
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(*.g.t with 2,3,7,8-TCDD). As illustrated below in Figure i; there is a significant
difference between the derivation of criteria for the protection of human health
(lower arrow), and the relationship between laboratory studies and the needs to
prosed a broad-, range of wildlife species at the local populafcioa level (upper
arrow).
Figure 1
Tru« Spectrum of Wildlife Species Sensitivities Existing In the Field
Most
Sensitive , - ResiStoni
Wildlife Criferlo (bassd on centre.) *elu* of
— __ „— , . minvs somt metric of variability)
of
(N
Lob end/or flsJci studies
.-_ J
....... .
CriMfjOn (b«'*«si o«* most stnsltivf
u«certainiy foe(ers)
TITLE: Conctptual Differences 'Between- Derivations of -Criteria
for Protection of Human- Health and-Wildlife
The question of how to account for the spectrum of differences IB species
seasititities is far from simple. It is'essentially impossible to Mtntfiy the "most
sensitive" species, because .the most sensitive species status is likely to be chemical
specific. Ideally one would have chronic toziciiy data on a broad range of species*
so that the range of species sensitivities could be determined directly.
23
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Alternatively, one could determine the tinge of species sensitivities by some means
of extrapolation based upon & statistical analysis of a sampling of data relevant to
species sensitivities. Potentially useful examples are: the lower 95th confidence
limit of the geometric mtan of NQAELs from chronic toxiciiy studies in a
spectrum of species-, the 6th percentile of the pereentile distribution of NOAELs
from chronic toxicity studies; a chosen percentile of a Monte Carlo simulation from
chronic NOAELs, If there are insufficient chronic toxicity studies, then one could
resort" to the range of species sensitivities In acute toxicity tests* coupled with the
application of an acute toxicity to chronic toxicity ratio akin to the procedures
employed for the derivation of ambient water quality criteria for the protection of
aquatic life, However, the acute to chronic ratio is probably not & constant, as^h&s
been pointed out previously in SAB comments on the methodologies- for the
development of criteria for the protection of aquatic life. The Subcommittee
recommends that the methodology for deriving wildlife criteria incorporate
procedures that address a measure of the variability of species sensitivities
observed in substance specific studies.
The proposed approach suggests that mink or kingfishers art the most
exposed and/or sensitive species, and that a species sensitivity factor (SSF) ranging
from 0,1 to 1 as a multiplier can account for any additional contingencies,
considering that the exact value of the SSF needs to be based upon best
professional judgment As the procedures move from a direct assessment to
indirect indicators, their reliability deteriorates.
**4
Wildlife criteria need to take account of the principles and uncertainties of
extrapolating information across evolutionary, spatial and temporal dimensions.
Furthermore, the developers of the wildlife criteria methods also need to recognize
that the uncertainties in this process accumulate in complex ways because the
available data are based on conditions that may not occur in the field.
In special cases wildlife criteria need to be constructed so that they are able
to protect the individual rather than the population. This can be an important
consideration for endangered species, or for species covered by various treaty
obligations that prohibit the "taking" of individuals.
4.6 Interpretation o£ Toxicity Data
The majority of the toxicologies! information for chemicals that are known
to predominate in the Great Lakes system, has been derived either in direct
24
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support of criteria' for the protection of toman health, or it lias been generated as
part of research into the basic toxicology of these chemicals. Consequently, much
of the Information that is cited in support of the wildEft criteria was generated in
studies that were not designed to support the devetopm«nt"of such criteria.
Therefore, most of the extant information suffers from various deficiencies.
46.1 LOAEL vs. NQAEL
The discussions of the LOAEL v. NQAEL issues in the Technical Support
Document are veiy superficial, The discussions cover the degree of adjustment
required to estimate an NOAEL when the available information is based only uppir
an LOAEL. This issue is seriously confounded with -the range of species
sensitivities discussed .above, and furthermore it is strongly influenced by the
dosage spacing that was used in the chronic toxicity study. It is very important to
remember that the entire evaluative structure involving the "NOEL * NQAEL -
LOAEL - Severity of Effect" concepts, was formulated for a human health risk
assessment paradigm. Although these concepts can serve as sources of inspiration,
they cannot serve as foundations for the development of criteria methodologies for
the protection of wildlife or anything other than humans. For example,
biochemical changes and the induction of enzymes without concomitant
histopathological changes, may be of significance for the development of criteria
for the protection of the human individual. It is not at all apparent to what
extent such changes might influence the long-term success of local or regional
wildlife populations. The Subcommittee recommends that tKe Agency develop
guidance for the selection of NQAELs appropriate for the protection of wildlife
populations as distinct from the protection of individuals,
The principal message here is that the interpretations concerning specific
effects extrapolated to the well-being of a human individual or those for the
maintenance of sensitive wildlife populations, are fundamentally different
Consequently, it is unlikely that criteria for the protection of wildlife can be
created by relatively .mine1; adjustments to the methods that have been developed
for the derivation of the criteria for the protection of human health. The
uncertainty factor that seeks to relate the LOAEL to the NOAEL is related to the
spacing of the dosing regime chosen by the investigator.
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46,2 Sofeebronle to Chronic Iktrapoktion
The proposed methodology suggests that an up to 10-fold uncertainty feetor
bt applied to subchronic studies. Reproductive and developmental toxicity studies
art inherently short-term studies which do not merit the application of sub-chronic
to chronic uncertainty factors. Evtn among target organ toxicity studies, there are
many instances where sub-chronic studies are actually more sensitive than the
chronic studies carried out on the same substance. As animals age, various organ
Systems deteriorate in function and Hstological structure (e.g., kidney studies by
Coleman et al., 1977). This deterioration is common in most organ systems. As a
result it becomes increasingly difficult to discern damage to these organ systems V
induced by chronic exposures to chemicals as animals age, because the
deteriorating status of these organ systems in control animals obscures the effects
produced by the exposure to the test substance. Further evidence for this
phenomenon is provided by McNsmara (1076) who found that 90 day studies were
more sensitive thin life-time studies in over half of all cases, so that the ratios
between dose rates at which comparable effects were seen at 90 days relative to
their dose rates at the end of the life span, ranged from 0.1 to 10. The
methodology should discuss this problem and provide a rationale for when the 10-
fold uncertainly factor is appropriate for subchronic results, Further, the
methodology should note that s id-fold uncertainty may also he appropriate for
chronic studies due to the masking of effects caused by aging test animals.
4.6.3 Field and Laboratory Study Information
Experimental toxicology studits and fit Id studies provide complementary
information. Experimental studies provide precise dose-response information
under simplified and controlled conditions. The causal relationship between dose
and response can usually be clearly demonstrated, but the ability to interpret the
applicability of the information is constrained by the artificiality of the test
conditions.
Although field studies provide direct information on the response of species
under real-world conditions, this information often exists only in terms of
associations, Such associations offer important opportunities to identify effects of
*
concern and target them for priority research. However, in field studies the
question of causality can rarely be established without question. Hill (1965) listed
a sat of criteria for establishing causality when positive associations are found to
exist (Table II),
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Table E
Criteria for the Evaluation of Causal Associations
STRENGTH: & high magnitude of effect is associated with **pb*u*e to thft
CONSISTENCY: the association is repeatedly observed under different cj
SPECIFICITY; the effect is diagnostic of a streffiw.
TEMPORALITY: the stresaor precedes the effect in time.
OF A BIOIXXHCAL GI^DIENT; a ^ V
stressor and the response.
A PLAUSIBLE MECHANISM OF ACTION: some understanding of the functional
relationship between stressor and effect.
COHERENCE: the hypothesis does not conflict with knowledge of natural history and
biology.,
EXPERIMENTAL EVIDENCE: laboratory results which support a hypothesis.
ANALOGY: similar stressors cause similar responses.
After Kill CldiS).
The difference is closely analogous to that between experimental toxicology
studies and epidemiologies! studies in human health risk assessment. Hill's
criteria need to be applied with care. Absence of information on some criterion
only implies that causality cannot be established, not that it cannot exist Both
laboratory and field studies provide important information, both contribute to the
weight of evidence, and Both should be used for complete assessment "of qualitative
and quantitative respotists. .... . 4 . , ,
4.6.4 Tissue Residues
, t * * * .
Tissue residues in the target species can be used as indicators of exposure*
and if the organisms have achieved equilibrium concentrations, then they can also
be used as measures of exposure. When the basic modelling information is
available, then the tissue concentrations' can be intigratid with physiologically
based pharmacokinetic models (PB/PK models) and these can in turn be integrated
with laboratory toxieity information arranged in biologically based dose/response
27
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models (BBDR models). These models are at the cutting edge of tojdeological
research, and they are being investigated vigorously, because they appear to offer
the best way of bridging the differences in toxicologies! responses among different
experimental systems. The field of wildlife toxicology needs to be a prominent
part of this effort. :
At present, tissue residue data have often been the first indication that the
inputs of chemicals into a large system like the Great Lakes Basin have exceeded
the rates at which the chemicals can become biologically unavailable through &
variety of processes,
47 Tier 2
More information is needed before the Tier 2 wildlife proposal can be
evaluated completely. In principle, it appears reasonable to develop interim
"values" for chemicals for which some data are available, but are insufficient to
establish a Tier 1 wildlife criterion. However, the major differences in the
minimum data requirements specified for Tier 1 criterion development compared
to Tier 2 revolves around the use of sub-chronic vt chronic studies. Compared to
the problems inherent in the development of Tier 1 criteria;, the further
distinctions introduced in the Tier 2 methodology are trivial,
There are clearly advantages to having a form of TieriJ criteria or "interim1*
criteria for wildlife. The present proposal represents only minor differences to
Tier 1, it does not make scientific justifications for the magnitude of the
uncertainty factor that Tier 2 requires, and it is does not provide justifications or
scientific advice on implementation needed for risk management that is consistent
with the concepts of Banti-baeksHdmg» non-degradation,-zero-discharge, and virtual
elimination of toxics" programs,
4.8 Individual Criteria Documents
Previous reviews of these substances for other criteria or health assessment
documents have required the full time efforts of special review panels specifically
constituted for each substance. Typically each review has taken more than one
day. This SAB Subcommittee was not constituted to conduct compound specific
reviews.
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49 Toridty Equivalent Factors (TlFs)
The TEF values have been developed to estimate the relative toaieltSes of
PCDDs and PCDFs, with a recent interest to Include appropriate PCS eonpatis,
The major impetus for this development has been the concern for carcinogenicity.
Issues related to the fundamental assessment of the toxidty of dioxins and selected
dioxin-like compounds were reviewed by the Dioxin Ecotox Subcommittee (Science
Advisory Board, 1992). A concern expressed by this Subcommittee is whether
TEFs developed to assess relative carcinogenic potency are alsb applicable to
assess effects on reproductive and developmental toxicity. Furthermore, it is
unclear to what extent TEFi developed largely in mammalian systems are *, -
applicable to avian or other wildlife species.
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5. BIOACCUMULATION FACTORS
6,1 General Comments
The GLWQI documents present a good explanation of bioaecumuktkm and
the need to consider it rather than only bioconcentration in the establishment of
management scenarios for the Great Lakes environment. In the absence of field
derived data, the Initiative attempts to generate criteria for human health and
wildlife based on bioaeeumuktion factors derived from perceived trophic levels,
organism lipid estimates, and octtnol«water partition coefficient (K^). These '
endeavors are admirable and the Subcommittee encourages EPA and the Great
Lakes states to continue to explore these approaches and address some problems
associated with them.
The Subcommittee finds that the BAF procediire is more advanced and
scientifically credible than existing simple BCF procedures, Tht use of the BCF,
Food Chain Multiplier (FCM), and BAF approach appear to be fundamentally
sound.' However, a major inconsistency exists between Held data, for some
chemicals (Reinert, 1970) and the conceptual mode! of Thomann (1989) for food
chain derived residues. Efforts should be devoted to clarifying and improving the
documentation and the issues discussed below with a view to presenting a straight-
forward procedure with associated estimates of confidence levels. It is the
Subcommittee's opinion that with some modification a credible BAF estimation
method can be developed exploiting present knowledge.
5.2 Field Measured Bioacctunulation Factors
A "field" BAF is the ratio of the concentration of a chemical in feral fish to
its concentration in water from the same locality. Generally the water
concentration in question is "total" rather than truly dissolved or "available". Few
such "field" data exist (see for example, Reinert (1970) and Reinert and Bergman
(1974)), but they do demonstrate convincingly that field BAFs exceed laboratory
bioconcentration factors (BCFs) by a substantial factor for many hydrophobic
chemicals. While field measurements should be an acceptable measure of BAF,
there can be considerable error due to factors such as temporal changes in
concentration of the contaminant, analytical errors, whether dissolved or
suspended concentrations were determined, variable uptake rates by individual
fish, mortality of target species, and fish mobility,
SO
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Reinert-(197Q) and Reiaert and Bergman (1974) found that the
concentrations of DDT and Dieldrin in relation to fish, lipids ("oils") were nearly
constant across all aquatic trophic levels. Generally, the percent lipid increased at
higher trophic levels and with the length of the fisk For "these lipophilic
pesticides, reporting residues based on lipid minimises the effect of the food chain.
EPA should update its model in relation to these data.
Field BAFs must be interpreted very carefully, and it should be recognized
that they may contain substantial errors and variability due to the following
reasons:
i. >Mt
*•
a) Analytical methodologies generally determine total concentrations all
of which may not he biologically available;
b) There may be a loss of analyte by sorption or evaporation during
sampling;
c) Incomplete extractions may occur, especially if there is a high organic
carbon' content in the water;
d) Temporal and spatial variability in water concentration may occur
due to season, temperature, depth, hydrology, meteorology, and
microbial and photolytlc activity;
•.
e) There is likely to be variability in fish concentrations due to size, age,
sex, season, pre- or post-spawning status, migration, the nature of and
availability of food, the structure of the food chain, differences in lipid
content, parasite infestation and general health of the organism-
Given these potentials for error, EPA, should discuss and quantify the variance in
field derived BAFs in its guidance, along with.FCM estimates and attempt to
identify the magnitudes of natural variability and analytical errors in each
criterion data base, and estimate the impacts on the BCFs and FCMs.
In many cases, the laboratory generated BCF data are likely to be more
analytically accurate, but they .may be less representative than BAF, in that they
do not reflect natural variabilities, especially on food uptake. Therefore, field
measured BAFs are suitable for the'calculation of criteria but with the
qualifications that the data must be interpreted carefully and all information
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should be exploited. Specific guidelines need to bi developed for the acceptability
of residue data in tissues and dissolved concentrations in water. This will likely
require a research effort to determine the appropriate sampling procedures, such
as the number of organisms per station, the sampling frequency, or filtered/
tmfiJtered water.
To help alleviate the problem, EPA needs to support a research program to
develop more sensitive analytical methodologies for hydrophobia chemicaJs In
tissues, sediments and water. Consideration should be given to the establishment
of a formalized analytical chemistry program which utilizes the best scientists, the,
best instrumentation, tdtquati support, etc,, to develop analytical methodologies'
and perform analyses that are not readily achievable by "normal" laboratories.
Support to universities and industrial support to develop analytical reference
materials would help ensure the success of the program.
At present, water concentrations in field derived bioaceumulatian
calculations are assumed to be totals, Le,» Cf -C^+Cp. There are abundant
arguments in literature that show that dissolved (C^) and particle bound (Cp)
contaminants have different availabilities over time. This concept is certainly
recognized in the Agency's effort designed to develop sediment quality criteria.
One can thus ask the question: if the science underlying the development of
sediment quality criteria recognizes partitioning because dissolved and particulate
associated contaminants present different bioavailabflities, wljy do water quality
criteria not incorporate this state-of-the-art understanding of speciation and phase
partitioning? The Subcommittee recommends that these factors be presented as
part of the criterion methodology with a clear and defensible explanation as to
why GLI ignores these factors.
5.8 Adjusting BCFs to BAFs
Theoretically derived bioaccumulation factors appear to be based upon
accepted concepts of how chemical exchange between water, food, and fish; but
they have not been applied to enough field conditions to judge if the predictions
are realistic. Thomann's (198S) model for bioaeeumulation incorporates the
appropriate transfer coefficients for uptake via food intake and allows for rates of
excretion. Biotransformation can be included, however rates of biotransformatioii
cannot be estimated adequately from physical/chemical properties such as K^, and
therefore must be determined experimentally for each compound, or at least each
functionally related group of compounds. There is also considerable uncertainty
32
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about die factors controlling food uptake efficiency. The Thomann (1S89) model
assumes that the lipid-normallzed BCF is equal to E^. at zero growth and at
''equilibrium*1. This basic assumption does mot allow for oxidative metabolism and
biosynthetic conjugation with KydropMic Hgands such as glueuronic acid* sulfates,
and acetates. The model has not been adequately tested to use for the
establishment of regional water quality criteria at this time. The potential exists
for errors on both over-protection and under-proteetion of aquatic organisms,
wildlife and humans. It Is noteworthy that almost all bioacctimulation work has
focussed on non-metabolizing, non-polar, chlorinated hydrocarbons. Relatively
little has been done on metabolkable chemicals such as PAHs or phenols.
t
The Subcommittee is particularly concerned that consideration of
metabolism is not included. Admittedly it is difficult to find rate constant data
but for certain chemicals such as the PAHs, however, metabolism is an important
determinant 6f BAP, Metabolism may become more significant when lipid stores
are reduced at times of stress and lipophilic chemicals become mobilized.
Metabolism is also an important detoxification mechanism. In principle,
metabolism can invalidate the use of the simple FOM approach but the
Subcommittee is unable to suggest an alternative other than the use of reliable
field BAF's,
It should be noted that Thomann's (1989) model gives only very general
expressions for respiration rate, feeding rate and growth rate as a function, of
organism mass. More accurate species-specific data exist for"'these rates which
could be used instead, presumably giving greater accuracy. The option to use such
data should be included.
1 5
At present the GLI procedures use an equation for BCF developed by the
Buluth Environmental Besearch Laboratory plus .the Thomann (1989) equation for
FCM, The Subcommittee recommends that the GLWQI use either the entire
Thomann (19S9) approach, which has been tested or test the validity of the
GLWQI combination, of approaches. The significant difference is that the Veiiii
and Kosian .approach does not view the bioconcentration'as simple lipid
partitioning.
Laboratory generated BCF values can be measured in a number of ways.
Systems prescribed by EPA and OECD include: static, sequential static, semi-
static, and flow-througii systems. In addition,, conditions such as times of exposure
and kinetic frameworks may be specified. It is now'becoming evident that Log
-------
KpW-BCF relationships work well for chlorinated organic chemicals with low to
medium molecular weights (<500 - 600) and for which no biotransfonnation
occurs. Carefully specified procedures for measuring and estimating BCFs and Log
Kow for other classes of compounds must be developed and evaluated. A proper
testing protocol should be able to accommodate questions as to such effects as;
influence of pH, especially for those compounds that dissociate; the influence of
mixtures on bioavailability, solubility, and general partitioning; the influence of age
on different fishes and their capacity to bioaccumulate; and the influence of a
third phase (i.e. suspended or bottom sediments) on BCFs.
BCF relationships for metals present a special problem, as recognized by the
authors of the GLI document. The Subcommittee strongly wges the authors to
pay particular attention to the fact that total analytical concentrations of metals
(and organically completed metals) may not represent the "activity* of that metal
Enough is known now about aqueous metal sptciation, precipitation behavior, and
solids partitioning to incorporate this body of. knowledge -into scientifically rigorous
criteria protocols. The Subcommittee recommends that the GLWQI coEaborate
with modeling specialists from the EPA Athens laboratory.
5.4 BCF for lo K above 5,0
At present the BAP confidence intervals for chemicals with log Kww < 5
appear to be quite tight while those in the range of 5 to 6.5 have confidence
intervals which may be more than an order of magnitude wide. In the range
beyond §.5, the confidence is not known within reasonable limits. This situation
is less than satisfactory for a regulatory program.
The treatment of super hydrophobic chemicals, e.g.» those with log K^, >
6,5, by assigning them an arbitrary PCM of 1.0 is viewed as merefy an admission
of ignorance. This presents a problem in that most of the chemicals in this range
have high molecular weights and volumes and they may be subject to slow
absorption and clearance as a result of retarded diffusion through absorbing
tissues. EPA should consider other approaches to handling these substances such
as:
a) Using only field BAF's in such cases;
b) Conducting chemical specific assessments;
c) Assuming all chemicals with log K^w > 6,5 behave similarly to one
with a log Kow= $.5 for which the BCF is accurately known.
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This is clearlyta 'area in which mort research is needed, The field of
bioaceuimilation is clearly of importance in the GLI process. Considerable
progress has been made in recent years towards understanding the factors
influencing BAPs. Notable are the experimental studies at the 1PA laboratory in
Duluth and the modeling work at the Athens laboratory and at Manhattan
College. There is a need to bring together the available scientific expertise in.
water chemistry analysis, fish physiology and pharmacokinetics, biochemistry, and
food chain structure and fish ecology with mathematical modeling to derive
credible, validated BAF models. A combination of thoughtfully designed laboratory
stadias and fitld investigations is needed. To date, the work being esploited is
fragmented. The modeling approach of the Athens group is promising, but thesTf -
is a need for more active cooperation between modelers, and biologists, the latter
being in the best position to understand the nature of the complex series of events
which comprise bioaccumulaMon. In short, EPA should mount a specific research
program in this area to satisfy the needs of programs such as the GLL
5.5 Analytical Methodology for Compliance
The present GLI document presents numerical criteria values for four
chemicals. The criteria for several of these chemicals, and presumably for a host
of others, will be less than the analytical detection capabilities of many
laboratories. Additionally, because aquatic systems receive contaminants from
other point and non-point sources, the ambient concentration of a chemical in
question may already exceed proposed criteria. The Subcommittee recognizes that
it is entirely plausible to arrive at a scientifically defensible concentration value
which is orders of magnitude below present analytical detection levels. However,
EPA should provide implementation guidelines for the discharger to deal with
monitoring criterion values that are below present limits of detection and
situations where present ambient concentrations, derived from possibly a nsuMtode
of sources (including atmospheric sources), far exceed proposed criteria.
The Subcommittee suggest several approaches. The dischargers could
estimate the mass of discharged pollutant and, together with known volumes of
water flow, calculate theoretical concentrations; if the substance is hydrophoMc,
samples of the suspended solids should be analyzed. It is possible that analysis of
surfiekl sediments maybe more reliable than analysis of water. The dissolved and
total concentrations could be estimated using partitioning theories. Caged fish
could be used as "accumulators" for specified time periods to estimate BCF values
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for field exposures. Surrogate "accumulators", such as dialysis bags filled with
appropriate solvents could also be used.
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6. HUMAN HEALTH CEITEHI4
6.1 General Comments
Conceptually, the Great Lakes Initiative Has significant implications for
improving the ability to assess health hazards associated with water contaminants
in the Great Lakes Basin. The National Program has never before specified a
minimum data set for estimating water quality criteria related to human health.
The tiered approach suggested offers a mechanism for improving the data base
necessary to reduce, the uncertainties in risk assessment In the national criteria'
and to develop appropriate data for compounds released to the Great Lakes; Basin
for which national criteria do not exist. On the other hand, the process lias the
potential for being somewhat frivolously applied to chemicals which should be
regarded as safe without specific testing. Within this group would MI natural
substrates consumed in food as a source of calories (e.g., fatty acids, sugars, amino
acids).
There are also some serious difficulties with the way the tiers are
constructed. It is not possible to argue that Tier 1 chemicals protect against
reproductive developmenttl/teratogenic or carcinopnie endpoints because the
minimum data base does not require data that are appropriate for estimating
hazards of these types. In other words* chemicals can be classified as non-
carcinogens or without reproductive/developmental effects by not being tested for
these endpoicts. The lack of "such data is adjusted for by additional uncertainly
factors in the case of reproductive/developmental tfiiits, but no adjustment was
made for lack of data on caftinogenesis/ '
The Subcommittee suggests that compounds that lack dala on"
earemopnesii, reproductive and developmental/teratogenic effects be relegated to
Tier 2. Therefore, Tier 2 would .serve to identify those chemicals for which an
inadequate data base exists. The generation of the appropriate data could be
rewarded by smaller uncertainty factors and movement into a Tier 1 criteria.
Certain of the criteria developed in the Great Lakes Water Quality Initiative
will inevitably bring up conflicts in risks to the ecosystem or specific wildlife
relative to risks to human health, A specific example of such a circumstance
would b6 the disinfection of wastewater effluents to prevent infectious disease
transmission. Such treatments inevitably lead to the formation of a variety of by-
. 37
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products which- may represent somi finite ecological risk. To reduce or eliminate
disinfection of such effluents might result in a substantial impact on huinsii
health. The potential magnitude of such risks relative to risks associated with
some potential bioteeumulative compounds whose estimate! risks frequently
depend upon multiplicative factors that may or may not be realized In the real
world might present a very distorted view of the benefits of regulation. The
documentation provided dots not provide any perspective to how such issues might
be resolved.
The Subcommittee suggests that the EPA should be much more explicit in
balancing human health risks with ecological risks. The EPA should either
exempt chemicals added to water for puhEc health purposes or modify ambient
water quality criteria to allow for prudent use of these chemicals. This needs to
be addressed at the national level, not only in relationship with the GLWQL
Another major concern is what the impact this local or regional activity will
have on the development of national standards. While many of the aims of this
program are laudable, differences in the criteria or the types of compounds toat
are limited between the national and local level are likely to lead to confusion and
distrust on the part of the public served,
6.2 Thresholds for Carcinogens
The approach, taken in earcinogenesis risk assessment in the Initiative is
over simplistic and does not break out the questions in such a way as to
encourage concise development of the rationale for the risk assessment. The
current technical guidance should be revised to reflect the following discussion.
Weight of evidence issues simply address the question of whether available
data indicates that humans would be sensitive to the carcinogenic effects of the
chemical. This decision would be based on the consistency of the carcinogenic
response across species using1 criteria articulated by both EPA and IAEO. A more
recent refinement of these criteria includes specific questions of whether the
mechanism for producing cancer in experimental animals exists in humans. This
latter question has been explicitly considered in recent deliberations on chemicals
that induce accumulation of alpha-2U-globulin in male rats, compounds which are
peroxisome proliferators in rodents and substances which induce thyroid tumors.
38
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The method by which low dose extrapolation is conducted should not be
simply viewed as a question of threshold QT non-threshold carcinogens* To tat
extent possible the t^dnogewe response should be modeled in the context of the
mechanisms by which the chemical induces the cancer. These considerations need
to be included independently of whether the chemical has been shown carcinogenic
In humans or only in experimental animate, Several research groups are
developing data that will alow the independent contribution of mutagenic and eel
proliferates effects of a chemical to the carcinogenic response to be modeled,
Additionally, data are being developed which allow the effective dose of the
responsible metabolites to be estimated across species with much more confidence
utffizinf physiolof^eally-based pharmacokmetic (PBPK) models, Wntn such *, -
information Is available it should be utilized in estimating carcinogenic risks at
low doses. As it happens both mechanistic and pharmacokinetic data are being
developed for a number of compounds that are being considered for developing
water Quality criteria. It. is .important to note that treatment of individual
chemicals in this process may be complicated and perhaps controversial. The
Subcommittee recommends that the GLWQI coordinate with other programs in
EPA that are currently addressing these issues. A partial list of chemicals that
will receive much attention in the near future axe dioxia, ehloroform, PCBs,
trichloroethylene, tetracMoroethylane, and the phthalates.
In the interim, the linearized multistage model is a reasonable, default
methodology for the many chemicals for which these more detailed data are not
available, However, the Agency must utilize available information on the
mechanisms carcinogens to modify this assumption whenever data are considered
to be reliable,
6,3 Additive Bisks for Carcinogens
The assumption of additivity for chemical carcinogens is difficult to accept
as & default at low doses, Additivity assumes a common mechanism of action*
This is probably an infrequent condition since compounds classified as carcinogens
are known to act by a wide variety of mechanisms and to target different organs,
Moreover, compounds which operate by different mechanisms, mutagenlc versus
non-mutagenid, are likely to be synergistic at effective doits but less than additive
at low doses.
Within the confines of compounds that act at the same receptor (e.g.,
djosdns, fufans and PCBs) an assumption of additivity might well be defeasible.
39
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However, it must be recognized that such interactions can also be antagonistic, a
weaker activator of the receptor may actually inhibit the effects of a mom effective
activator (it. acting as a partial aatagotttetjh ;Cte;tite--other hand, synergistic
activity "can b£ expected to occur between compounds tctMg by different
mechanisms within the same target organ, ^he classic example are compounds
that tet by mutation vs. induction of cell proliferation- It is clear, however, that
the latter chemicals must be presentedJn doses that, either produce sustained,
levels of increased cell division or prevent ceU deatl in the target organ. Thus,
such interactions are unlikely to occur at, low. doses.
• ' * ": -. , ** •
The SAB recommends that the.GliI consider the probability of interaction
between carcinogens on a case by caSH basis. These interactions must also be
taken into account within the context of their co-occurrence in fish tissue rather
than from simple projections of their concentrations based on occurrence to
effluents. The compound? might well take entirely separate environmental
pathways, It would1 be unwise t<5 project potential errors of an interaction on top
of errors in risk assessment and projections of bioaccumulation.
6.4 Tier 1 Minimum Data Base
Tier 1 should be reserved for those compounds that have'been adequately
tested. To include chemicals in Tier 1 which,have not been adequately tested for
carcinogenic, reproductive or developmen£al/&ratogenic-effects is inconsistent with
the stated goals of the initiatives A-coroJkry.to.this is that 'a^Tier 1 compound
should not carry an extra uncertainty factor for lack of appropriate data,
With this suggested reconstitution of Tier 1, the C carcinogen classification
would include chemicals that had been adequately tested and the weight of
evidence does not support the notion that they are probable human carcinogens.
Therefore, they would not be treated as carcinogens in developing the criteria.
These chemicals should be clearly distinguished from those which have received
their C classification because they have only been tested in m single species. The
absence of data in one or more other specits essentially frustrates the development
of a weight of evidence argument. Therefore, such chemicals should be relegated
to Tier 2 and treated as suspect carcinogens. A more conservative assessment
could be justified to force completion of a data bast on the chemical that will
allow a proper judgement to be made,
40
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6.5 Tier 2 Concept
Under the proposed Tie? 1 and Tier 2, earcinogtns classified as C would be
treated more conservatively if they fell into Tier 2. This seems more consistent
with the overall aims of Tier 2, the development of a guidance that encourages the
development of more definitive data.
The we of a 28-day itudy (tie term swbaeuti should be abandoned) to
produce a NOABL as the minimum data set for Tier 2 may be marginal for
detecting some chronic human health effects. The latent period for some well
defined chronic effects approach this limit (e.g., peripheral neuropathies produced
by acryjamide, n-hexane or methylbutylketone) and some exceed it (&&» peripheral
neuropathy produced by dicMoroacetate). More speculative neisrotoaddties may
have even longer latencies (e,g,» aluminum induced neurofibrfllary tangles).
On the other hand, data, from experiments of 28 days duration are better
than no data at all. It is important that these data be developed in an accepted
mammalian species and that additional uncertainty factors compensate for the
significantly less sensitive detection limits that Witt result from the shorter
duration of the experiments,
A more broadly cast function for the Tier 2 concept should make it more
defensible. As indicated above one may reluctantly start with a mfaiTwm data
base of a 28-day study, but other critical data deficiencies should also place
compounds into this class
6.6 Chemical Mtitagens
There are substantive difficulties in determining whether chemicals Induce
these effects by "genotoxie* mechanisms. Consequently, it is impossible to consider
this question without knowing what the mfrifamin data base for determining
whether a genotoxie mechanism is involved. Clearly one cannot use bacterial or w
vitm methods for determining whether & chemical will produce a heritable
mutation in humans, Damage to the germ cell line can only be gaged by in vivo
heritable mutation assays. On the other hand, the whole animal tests available in
this area are inordinately insensitive or very expensive to conduct.
In addition to demonstrating1 that the effect is the result of a genotoxie
mechanism, some effort must be expended to develop a methodology for
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extrapolating these data to low doses. Risk assessment models to predict tht
induction, of heritable mutations and/or genotoxie teratogenk effects must consider
other factors (e.gf, spontaneous abortion) that influence the outcome. Thus, simple
application of the same risk assessment models ustd for cancer may not be
appropriate. Consequently, a case must be developed for any extrapolation model
that would be used before the Subcommittee can usefully comment on this
proposal. There have been some recent efforts in this area that have been
published in the literature, but consensus on this issue has not yet been reached.
6.7 Rektive Source Contributioa
f
Most persistent and bioaccumulative environmental contaminants offer a
substantial exposure potential through the food chain. In the case of water
contaminants,'fish fltsh represents a predominant food source of exposure. The
procedure proposes a difault 80% relative source contribution (ESC) for water
contaminants to account for fish flesh exposure as a predominant human exposure.
There might be individuals that have veiy high exposures in contaminated soil,
but this is such an irregular source that development of an HSC is unlikely to
protect such individuals anyway. Other sources (ie.» fish taktn from other sites)
are really already compensated for in the calculation of fish consumption.
Consequently, there seems little justification for any RSC for these chemicals. The
SAB believas that a factor of 80% is not supportable becaust it is within the
rounding error on the calculations of the overall exposure.,.
6.8 Additional Concerns
a) Tht criteria documents must explicitly consider issues that are critical
to the development of the either Tier 1 or Tier 2 criteria. Examples
are: 1) It is important to consider both positive and negative
carcinogenesis data to develop a weight of evidence argument that a
chemical is or is not to be considered a carcinogen. 2) The selection
of a NOAEL is strengthened by finding similar values for.similar
endpoints in several independent experiments. 3) The methods of
quantitative extrapolation of risks need to be supported by data
relevant to the chemical's mechanismCs) of action when such data is
available.
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b) Risk Assessments do not consider multiple routes of exposure posed
by volatile compounds.
The basis of the criterion is an assessment of human exposure
by drinkmg water and fish consumption only. Exposure by air
inhalation of chemical derived from water is not considered and
should be. For example* the toluene drinking water criteria of 6000
or 6 rag/L corresponds to an equilibrium concentration In air of
about 2 mg/L or 2 gfm . This greatly exceeds the occupational health
TLV (188 mg/m ). Water containing these concentrations of toluene „
will taste and smell offensive. Additionally, there is the fact that '
levels of 22,000 #g/L or 22 mg/L could represent a fire, hazard or an
explosion hazard in sewer systems. The point is that water and fish
consumption are not the only exposure routes or hazards to be
considered, especially 'for volatile chemicals.
EPA should consider adding an air inhalation term to the
exposure denominator in the form of some volume of air Va inhaled
which achieves equilibrium with the water,. It would become Wc +
(FC x BAF) -f Va x K^ where K^w is the air-water partition
• coefficient,
c) The data utilized and assumptions made to arrive at the 15 g/d for
consumption need to be more explicitly discussed.
d) Data and assumptions used to arrive at the Epid content need to be
made explicitly in the document.
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literature Cited
Coiiman, G.L., Barthold, S.W,» Qsbaldiston, G.W.; Foster, S.J. and AM, Jonas.
1977. Pathological changes during aging in barrier-reared Fischer 344 male
rates. jL Gerontology lK31;25S-278.
Hill, A.B. 1965, The environment and disease: association or causation?
Proceedings of the Royal §2£iity_ fif Medicine 68:295-300.
r
Host, G.» Regal, R. and C,L, Stephan. 4990, Analyses of Acute and Chronic Data
for Aquatic Life. EPA Environmental Research Laboratoiy-Duluth.
Lebo, JA.» Zajicek, J.L., Huckins, J,N,» Petty, J.D, and PJJ. Petermsn. 1992. Use
of semipermeabie membrane devices for insula monitoring of polycyclic
aromatic hydrocarbons in aquatic tnviroaments. ChemospKeyi g§;697-718.
Johnson, G.D. 1991, Hexane filled dialysis-bags for monitoring organic
contaminants in water. J, Environ. Sgj. Teehnol. 25:1897-1903.
McNamara, B.P. 1976, Concepts in health tvaluation of commercial and
industrial chemicals. Chapter 4 in: Ne\r Concepts in Safety Evaluation. M.A.
Mehlman, R.E. Shapiro, H. Blumenthal, eds. Advances in Modern To^ieoiogy
1(1) :61-140. Hemisphere Publishers, Washington, D.C,
Reinert, R. 1970. Pesticide concentrations in Great Lakes fish. Pesticide
Monitoring- Journal 3(4):97-lll.
Reinert, R.E. and HL, Bergman. 1974, Residues of DDT in Lake Trout
(SalwUnus namaycmh) and' Coho Salmon (Qkcorhynchus ki&uteh) from the
Great Lakes, 1. Fish. Res. Board Can. 31:191-199.
Science Advisory Board. 1988. Review of the Guidelines for Preparing Water
Quality Advisories, EPA-SAB-EETFC-88-032, July 1988, Washington, DC.
Science Advisory Board, 1992. Review of EPA's Research to Support Water
Quality Criteria for TCDD (Dioxin), EPA-SAB'EPEC-92-024, August 1992,
Washington, DC.
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R.Y.-1989, Bioaecumulation model of organic chemical distribution la
aquatic food chains. £ jBnviron. Set. jPeehnol. 2^:609-707.
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ABBHEVIATIONS AND DEFINITIONS
BAF Bioaeeumulation Factor* a ratio of the concentration of a chemical in
fish or tissue to concentration of the chemical" in water,
BCP Bioconcentration Factor, chemical-specific values used to predict tissue
residues derived through direct uptake of the chemical from water.
Board See SAB,
Clg Radioactively labelled carbon. . * "
DWC Drinking Water Committee, a standing committee of the Science
Advisory Board.
EEC Environmental Health Committee, a standing committee of the
Science Advisory Board.
EPEC Ecological Processes and Effects Committee, a standing committee of
the Science Advisory Board,
FAY Final Acute Value, a numerical estimate of the concentration of a
chemical in water that will protect aquatic life from acute toxkity.
This is usually a Tier 1 value based on a minimum data set of
toxicity ttst on a variety of aquatic species.
FCV Food chain multiplier, a value used to account for the concentration
of residue! predators obtain from, prey,
FWS U,S. Fish and Wildlife Service.
GL! Great Lakes Initiative.
GLWQI Great Lakes Water Quality Initiative, a coordinate EPA and State
effort to protect aquatic organisms and humans from the adverse
effects of persistent toxic pollutants in tht Great Lakes.
GMAV Genus Mean Acute Valut, another value used in the calculation of
aquatic life water quality criterii.
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HPLO
LC
LOAEL
NOAEL
NPDES
PAH
SAB
SAV
TEF
Tier 1
Tier 2
WQC
High Pressure Liquid Chromatography, a tool in analytical chemistry
used to measure the quantity of organic compounds.
Lethal Concentration, the concentration of a chemical which kills &
proportion of the test organisms (e.g., an LC50 is tfat concentration
that Mia 00% of the test organisms).
Lowest Observed Adverse Effect Level, the lowest test concentration
of a chemical at which & deleterious effect was measured,
No Observed Adverse Effect Level, the highest test ccmeentrataoa
chemical at which no deleterious effect was measured.
National PoEution Discharge Elimination System,
Polyaromatic Hydrocarbon compounds (e.g., styrene).
Science Advisory Board* a public advisory group operated by staff of
the EPA Administrator.
Secondary Acute Value, a Tier 2 value based on a limited data set,
designed to protect aquatic life from acute toxicity,
Tojdcity Equivalent Factor, a system for comparing the potency or
toxidty of mixtures of congeners of a chemical
Criteria values which are based on a minimum data set
testing1 and bioaccumulation data for a chemical The nature of the
minimum data set varies among aquatic life, wildlife, and human
health criteria, . ...
Criteria values based on a limited data set of toxicity testing for a
chemical,
Water Quality Criteria* numerical estimates of the levels of a chemical
in water that will protect aquatic organisms and humans. These
values are used by states as the foundation for- state water quality-
standard which are used to set limits in discharge permits.
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