Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health

185 Pages·2005·0.79 MB·English

United States Office of Water EPA-822-B-00-004
Environmental Protection Office of Science and Technology October 2000
Agency 4304
Methodology for Deriving Ambient
Water Quality Criteria for the
Protection of Human Health (2000)
EPA 822-B-00-004
October 2000
Methodology for Deriving
Ambient Water Quality Criteria
for the Protection of
Human Health (2000)

Final
Office of Science and Technology
Office of Water
U.S. Environmental Protection Agency
Washington, DC 20460
NOTICE
The policies and procedures set forth in this document are intended solely to describe
EPA methods for developing or revising ambient water quality criteria to protect human health,
pursuant to Section 304(a) of the Clean Water Act, and to serve as guidance to States and
authorized Tribes for developing their own water quality criteria. This guidance does not
substitute for the Clean Water Act or EPA’s regulations; nor is it a regulation itself. Thus, it
does not impose legally-binding requirements on EPA, States, Tribes or the regulated
community, and may not apply to a particular situation based upon the circumstances.
This document has been reviewed in accordance with U.S. Environmental Protection
Agency policy and approved for publication. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
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FOREWORD
This document presents EPA’s recommended Methodology for developing ambient water
quality criteria as required under Section 304(a) of the Clean Water Act (CWA). The
Methodology is guidance for scientific human health assessments used by EPA to develop,
publish, and from time to time revise, recommended criteria for water quality accurately
reflecting the latest scientific knowledge. The recommended criteria serve States and Tribes’
needs in their development of water quality standards under Section 303(c) of the CWA.
The term “water quality criteria” is used in two sections of the Clean Water Act, Section
304(a)(1) and Section 303(c)(2). The term has a different program impact in each section. In
Section 304, the term represents a scientific assessment of ecological and human health effects
that EPA recommends to States and authorized Tribes for establishing water quality standards
that ultimately provide a basis for controlling discharges or releases of pollutants. Ambient
water quality criteria associated with specific stream uses when adopted as State or Tribal water
quality standards under Section 303 define the maximum levels of a pollutant necessary to
protect designated uses in ambient waters. The water quality criteria adopted in the State or
Tribal water quality standards could have the same numerical limits as the criteria developed
under Section 304. However, in many situations States and authorized Tribes may want to
adjust water quality criteria developed under Section 304 to reflect local environmental
conditions and human exposure patterns before incorporation into water quality standards.
When adopting their water quality criteria, States and authorized Tribes have four options: (1)
adopt EPA’s 304(a) recommendations; (2) adopt 304(a) criteria modified to reflect site-specific
conditions; (3) develop criteria based on other scientifically defensible methods; or (4) establish
narrative criteria where numeric criteria cannot be determined.
EPA will use this Methodology to develop new ambient water quality criteria and to
revise existing recommended water quality criteria. It also provides States and authorized Tribes
the necessary guidance to adjust water quality criteria developed under Section 304 to reflect
local conditions or to develop their own water quality criteria using scientifically defensible
methods consistent with this Methodology. EPA encourages States and authorized Tribes to use
this Methodology to develop or revise water quality criteria to appropriately reflect local
conditions. EPA believes that ambient water quality criteria inherently require several risk
management decisions that are, in many cases, better made at the State, Tribal, or regional level.
Additional guidance to assist States and authorized Tribes in the modification of criteria based
on the Methodology will accompany this document in the form of three companion Technical
Support Documents on Risk Assessment, Exposure Assessment, and Bioaccumulation
Assessment.
___________________________
Geoffrey H. Grubbs
Director
Office of Science and Technology
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ACKNOWLEDGMENTS
Project Leader
Denis Borum U.S. EPA Office of Science and Technology
Coauthors
Risk Assessment
Joyce M. Donohue, Ph.D.* U.S. EPA Office of Science and Technology
Julie T. Du, Ph.D.* U.S. EPA Office of Science and Technology
Charles O. Abernathy, Ph.D. U.S. EPA Office of Science and Technology
Exposure
Denis Borum * U.S. EPA Office of Science and Technology
Helen Jacobs, M.S. U.S. EPA Office of Science and Technology
Henry Kahn, D.Sc. U.S. EPA Office of Science and Technology
Bioaccumulation
Keith G. Sappington, M.S.* U.S. EPA Office of Science and Technology
Lawrence P. Burkhard, Ph.D. U.S. EPA Office of Research and Development
Philip M. Cook, Ph.D. U.S. EPA Office of Research and Development
Erik L. Winchester, M.S. U.S. EPA Office of Science and Technology
U.S. EPA Technical Reviewers
William Beckwith U.S. EPA Region 1
Jeff Bigler U.S. EPA Office of Science and Technology
Sally Brough U.S. EPA Region 10
Karen Clark U.S. EPA Office of General Counsel
Gregory Currey U.S. EPA Office of Wastewater Management
Vicki Dellarco U.S. EPA Office of Prevention, Pesticides, and Toxic Substances
Charles Delos U.S. EPA Office of Science and Technology
Arnold Den U.S. EPA Region 9
Catherine Eiden U.S. EPA Office of Prevention, Pesticides, and Toxic Substances
Michael Firestone U.S. EPA Office of Prevention, Pesticides, and Toxic Substances
Steven Galson U.S. EPA Office of Prevention, Pesticides, and Toxic Substances
Sue Gilbertson U.S. EPA Office of Science and Technology
Denise Hakowski U.S. EPA Region 3
Joel Hansel U.S. EPA Region 4
Wayne Jackson U.S. EPA Region 2
Annie Jarabek U.S. EPA Office of Research and Development
William Jordan U.S. EPA Office of Prevention, Pesticides, and Toxic Substances
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Margaret Kelly U.S. EPA Office of Children’s Health Protection
Henry Lee U.S. EPA Office of Research and Development
Sharon Lin U.S. EPA Office of Wetlands, Oceans, and Watersheds
Roseanne Lorenzana U.S. EPA Region 10
Gregory McCabe U.S. EPA Region 7
Jennifer Mclain U.S. EPA Office of Ground Water and Drinking Water
Bruce Mintz U.S. EPA Office of Research and Development
Dave Moon U.S. EPA Region 8
William Morrow U.S. EPA Office of Science and Technology
Jacqueline Moya U.S. EPA Office of Research and Development
Deirdre Murphy U.S. EPA Office of Air Quality Planning and Standards
Joseph Nabholz U.S. EPA Office of Prevention, Pesticides, and Toxic Substances
Russell Nelson U.S. EPA Region 6
Jennifer Orme-Zavaleta U.S. EPA Office of Research and Development
Lynn Papa U.S. EPA Office of Research and Development
Robert Pepin U.S. EPA Region 5
David Pfeifer U.S. EPA Region 5
Rita Schoeny U.S. EPA Office of Science and Technology
Charles Stephan U.S. EPA Office of Research and Development
Linda Teuschler U.S. EPA Office of Research and Development
David Tomey U.S. EPA Region 1
Fritz Wagener U.S. EPA Region 4
Jennifer Wigal U.S. EPA Office of Science and Technology
Jeanette Wiltse U.S. EPA Office of Scence and Technology
Gary Wolinsky U.S. EPA Region 9
Philip Woods U.S. EPA Region 9
William Wuerthele U.S. EPA Region 8
* Principal U.S. EPA Author and Contact
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EXTERNAL
PEER REVIEW WORKGROUP
The following professionals were part of the External Peer Review Workgroup that provided
technical and scientific review regarding the content and technical approach in the July 1998
Draft Ambient Water Quality Criteria Derivation Methodology: Human Health. Their
comments were reviewed and incorporated where appropriate to develop this final document.
Kenneth T. Bogen, Ph.D. Lawrence Livermore National Laboratory
Paul E. Brubaker, Ph.D. P.E. Brubaker Associates
Peter L. DeFur, Ph.D. Virginia Commonwealth University
Karen Erstfeld, Ph.D. Rutgers University
Bob Fares, Ph.D. Environmental Standards, Inc.
Laura Green, Ph.D. Cambridge Environmental, Inc.
Robert Hales, Ph.D. Virginia Institute of Marine Science
Brendan Hickie, Ph.D. Trent University
Ernest Hodgson, Ph.D. North Carolina State University
Paul Locke, Ph.D. Johns Hopkins University
Lynn S. McCarty, Ph.D. LS McCarty Scientific Research and Consulting
Erik Rifkin, Ph.D. Rifkin and Associates, Inc.
Damian Shea, Ph.D. North Carolina State University
Nga Tran, Ph.D. Johns Hopkins University
Curtis Travis, Ph.D. Project Performance Corp.
Potential areas for conflict of interest were investigated via direct inquiry with the peer reviews
and review of their current affiliations. No conflicts of interest were identified.
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TABLE OF CONTENTS
Page
NOTICE .................................................................... ii
FOREWORD ................................................................ iii
ACKNOWLEDGMENTS .......................................................v
EXTERNAL PEER REVIEW WORKGROUP........................... .......... vii
CONTENTS ...................... ........................................... ix
TABLES AND FIGURES ..................................................... xiv
LIST OF ACRONYMS ........................................................xv
1. INTRODUCTION .................................................... 1-1
1.1 Water Quality Criteria and Standards ...................................... 1-1
1.2 Purpose of This Document ............................................... 1-1
1.3 History of the Ambient Water Quality Criteria (AWQC) Methodology ............ 1-2
1.4 Relationship of Water Quality Standards to AWQC ........................... 1-4
1.5 Need for the AWQC Methodology Revisions ................................ 1-4
1.5.1 Group C Chemicals .............................................. 1-6
1.5.2 Consideration of Non-Water Sources of Exposure ...................... 1-7
1.5.3 Cancer Risk Ranges .............................................. 1-8
1.6 Overview of the AWQC Methodology Revisions ............................. 1-9
1.7 References .......................................................... 1-13
2. CLARIFICATIONS ON THE METHODOLOGY, RISK CHARACTERIZATION,
AND OTHER ISSUES FOR DEVELOPING CRITERIA ................... 2-1
2.1 Identifying the Population Subgroup that the AWQC Should Protect ............. 2-1
2.2 Science, Science Policy, and Risk Management .............................. 2-3
2.3 Setting Criteria to Protect Against Multiple Exposures From Multiple Chemicals
(Cumulative Risk) ..................................................... 2-4
2.4 Cancer Risk Range .......................................... ........... 2-6
2.5 Microbiological Ambient Water Quality Criteria ............................. 2-7
2.6 Risk Characterization Considerations ...................................... 2-9
2.7 Discussion of Uncertainty .............................................. 2-11
2.7.1 Observed Range of Toxicity Versus Range of Environmental Exposure .... 2-11
2.7.2 Continuum of Preferred Data/Use of Defaults ......................... 2-11
2.7.3 Significant Figures .............................................. 2-11
2.8 Other Considerations .................................................. 2-13
2.8.1 Minimum Data Considerations .................................... 2-13
2.8.2 Site-Specific Criterion Calculation ................................. 2-13
2.8.3 Organoleptic Criteria ............................................ 2-14
2.8.4 Criteria for Chemical Classes ..................................... 2-15
2.8.5 Criteria for Essential Elements .................................... 2-16
2.9 References .......................................................... 2-16
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