&EPA
United States
Environmental Protection
Agency
Implementation Guidance for
Ambient Water Quality Criteria for
Bacteria
May 2002 Draft
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U.S. Environmental Protection Agency
Office of Water (4305T)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
EPA-823-B-02-003
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Foreword
Our Nation's waters are a valuable recreational resource. We use them for swimming and recreating,
to seek adventure through white water rafting, surfing, and kayaking, or simply enjoying their
aesthetic qualities while hiking or birdwatching. Protection of these waterbodies begins with state,
territory, and authorized tribal adoption of water quality standards. The draft Implementation
Guidance for Ambient Water Quality Criteria for Bacteria was written to provide guidance to state,
territory, and authorized tribal water quality programs on the adoption and implemention of
bacteriological water quality criteria for the protection of waters designated for recreation. This
document may also serve as a useful resource for state and local beach program managers and
interested members of the public.
This draft guidance takes into account feedback the Agency received on its previous February 2000
draft and subsequent interactions with interested stakeholders. In response to this feedback, the
scope and detail of this document increased significantly in comparison to EPA's February 2000
version. Consequently, we are providing this additional opportunity for public review of the
Implementation Guidance for Ambient Water Quality Criteria for Bacteria to ensure that all
interested parties have an opportunity to participate and offer comments on this important guidance.
Once finished, I believe you will find this document a useful resource. We look forward to receiving
your comments and working with you to ensure continued protection of our recreational waters.
Should you have any questions or concerns, please do not hesitate to contact me (202-566-0430) or
Elizabeth Southerland, Director of the Standards and Health Protection Division (202-566-0400).
3bs, Director
'Science and Technology
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NOTICE
The Implementation Guidance for Ambient Water Quality Criteria for Bacteria is
designed to address questions on implementing EPA's recommended water quality
criteria for bacteria within state, territory, and authorized tribal water quality
programs.
The guidance included hi this document cannot impose legally binding requirements
on EPA, states, territories, authorized tribes, or the regulated community. It cannot
substitute for Clean Water Act (CWA) requirements, EPA's regulations, or the
obligations imposed by consent decrees or enforcement orders. Further, this
guidance might not apply to a particular situation based upon the circumstances.
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Acknowledgments
PROJECT LEADER/PRIMARY AUTHOR
Jennifer Wigal U.S. EPA Office of Science and Technology
U.S. EPA WORKGROUP
William Beckwith
Robert Chominski
Pat Costello
Alfred Dufour
Kerianne Gardner
Helen Grebe
Joel Hansel
Stephanie Harris
Sandra Hellman
Rick Hoffmann
Susan Holdsworth
John Hopkins
Ann Jacobs
Bill Kramer
Charles Kovatch
Ronald Landy
Kathleen Mayo
Christy McAllister
Dave Moon
Mike Muse
Russell Nelson
Pam Noyes
Nena Nwachuku
Robin Oshiro
Latisha Parker
David Pfeifer
Marjorie Pitts
Sara Roser
Mike Schaub
Stephen Schaub
Carolann Siciliano
Sandra Spence
Gerard Stelma
Holiday Wirick
Gary WoKnsky
Philip Woods
MEMBERS
U.S. EPA Region 1
U.S. EPA Region 3
U.S. EPA Region 7
U.S. EPA Office of Research and Development
U.S. EPA Region 10
U.S. EPA Region 2
U.S. EPA Region 4
U.S. EPA Region 10
U.S. EPA Region 5
U.S. EPA Office of Science and Technology
U.S. EPA Office of Wetlands, Oceans, and Watersheds
U.S. EPA Office of Wastewater Management
U.S. EPA Region 7
U.S. EPA Office of Science and Technology
U.S. EPA Office of Science and Technology
U.S. EPA Region 3
U.S. EPA Region 5
U.S. EPA Region 3
U.S. EPA Region 8
U.S. EPA Office of Groundwater and Drinking Water
U.S. EPA Region 6
U.S. EPA Office of Research and Development
U.S. EPA Office of Science and Technology
U.S. EPA Office of Science and Technology
U.S. EPA Office of Science and Technology
U.S. EPA Region 5
U.S. EPA Office of Science and Technology
U.S. EPA Region 9
U.S. EPA Region 6
U.S. EPA Office of Science and Technology
U.S. EPA Office of General Counsel
U.S. EPA Region 8
U.S. EPA Office of Research and Development
U.S. EPA Region 5
U.S. EPA Region 9
U.S. EPA Region 9
IV
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Executive Summary
The purpose of this document is to provide guidance for the implementation of water quality
criteria for bacteria once adopted into state and tribal water quality standards. As part of these
recommendations, EPA is encouraging states and authorized tribes to use E. coli or enterococci as
the basis of their water quality criteria for bacteria to protect fresh recreational waters. For marine
recreational waters, EPA recommends the use of enterococci as the basis for water quality criteria
for bacteria. Further, for coastal recreational waters (i.e., marine waters, coastal estuaries, and the
Great Lakes), states are required to adopt bacteriological criteria as protective as EPA's Clean Water
Act §304(a) criteria recommendations by April 2004. EPA believes the use of E. coli and/or
enterococci are best suited to prevent acute gastrointestinal illness caused by the incidental ingestion
of fecally contaminated recreational waterbodies.
This document provides a summary of EPA's existing recommended water quality criteria
for bacteria that it published in 1986 as well as recommendations on the implementation of
bacteriological criteria for the protection of recreation uses once they have been adopted into a state
or authorized tribe's water quality standards. The use of water quality standards to protect
recreational waters encompasses abroad spectrum of waterbody types, from heavily-used ocean front
beach areas, to remote mountain streams. This document attempts to acknowledge these different
types of recreational uses and the different management choices that are available to states and tribes
in managing these water resources.
States and authorized tribes must adopt primary contact recreation wherever attainable for
all surface waters within their jurisdiction, and, in doing so, consider the use of the waterbody by
children and other susceptible groups. To provide protection of human health, states and tribes
should conduct sanitary surveys to identify sources of fecal pollution when high levels of bacteria
are observed.
In many circumstances, waterbodies are impacted by not only human sources of fecal
contamination, but also other animals, including wildlife. In these situations, based on ability of
warm-blooded animals to harbor and shed human pathogens, EPA feels it is inappropriate to
conclude that these sources present no risk to human health from waterbome pathogens.
Consequently, states and authorized tribes should not use broad exemptions from the bacteriological
criteria for waters designated for primary contact recreation based on the presumption that high
levels of bacteria resulting from non-human fecal contamination present no risk to human health.
This policy statement revises EPA's previous policy as stated in its 1994 Water Quality Standards
Handbook, which allowed states and authorized tribes to justify a decision not to apply the
bacteriological criteria to particular recreational waters when high concentrations of bacteria were
found to be of animal origin.
For heavily-used beach areas and other well-known or popular recreational areas, EPA
recommends a more conservative approach in the adoption and implementation of recreational water
quality standards, such as adoption of criteria based on lower illness rates, consideration of the use
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of the 75% confidence level as a single sample maximum value, frequent monitoring, and the use
of sanitary surveys to identify sources of fecal pollution.
For other types of waterbodies, states and authorized tribes may opt to use different
approaches in the management of their recreational waterbodies. For example, those states and
authorized tribes wishing to adopt bacteriological criteria based on the same illness rates for their
fresh and marine waters may adopt both fresh and marine water criteria based on illness rates no
greater than 14 illnesses per 1000 swimmers. For states and authorized tribes not opting for this
approach, the maximum illness rate upon which fresh water criteria should be based is 14 illnesses
per 1000 swimmers and the maximum illness rate upon which marine water criteria should be based
is 19 illnesses per 1000 swimmers.
In some instances, particularly in northern climates, states and authorized tribes may choose
to adopt seasonal recreation uses to protect primary contact recreation during the time of year it
occurs and to prevent excessive disinfection by dischargers during the winter months. Residual
chlorine in effluents can result in the formation of disinfection by-products, such as trihalomethanes
in surface waters, which can have an adverse effect on human health and aquatic life. In other
circumstances where a state or authorized tribe has determined that primary contact recreation is not
an existing use as defined by federal and state (or tribal) regulations, nor attainable for one of the
reasons identified in the federal and state (or tribal) regulations, states and authorized tribes may
adopt other categories of recreation such as intermittent primary contact recreation, wildlife impac ted
recreation, or secondary contact recreation.
In addition to providing recommendations on the adoption of recreational uses and protective
water quality criteria into water quality standards, the document also provides explanations of how
states' and authorized tribes' recreational water quality standards should be used to form the basis
for water quality-based National Pollutant Discharge Elimination System permits, assess and
determine attainment of water quality standards, and develop subsequent Total Maximum Daily
Loads and wasteload allocations.
While this document is focused primarily on the adoption and implementation of water
quality criteria for bacteria as part of a states' or tribes' recreational water quality standards, there
are some natural relationships between this topic and drinking water programs, shellfishing
programs, and beach management activities. This document provides brief discussions of these
relationships and, where appropriate, provides the reader with references where more information
may be obtained.
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Table of Contents
Acknowledgments 1V
Executive Summary 'v
1. Background and Introduction • 1
1.1 What is the purpose of this guidance? 3
1.2 Why is EPA publishing this guidance? 4
1.3 Who should use this guidance? • 5
1.4 What are EPA's recommended water quality criteria for bacteria? 5
1.5 What is the basis for EPA's 1986 water quality criteria for bacteria? 6
1.5.1 How were EPA's epidemiological studies conducted? 7
1.5.2 How were the data from EPA's epidemiological studies analyzed to
provide EPA's recommended water quality criteria for bacteria? 7
References :
2. Reaffirmation of EPA's Recommended Water Quality Criteria 10
2.1 Does EPA continue to support its Ambient Water Quality Criteria for Bacteria -
1986? • 10
2.2 Have subsequent studies affected EPA's recommended water quality criteria for
bacteria? ; • •. 'o12
2.3 Is EPA planning on conducting additional epidemiological studies in the future?
" 14
References
3. Relationship Between Water Quality Standards and Beach Monitoring and
Advisory Programs
3.1 What are the BEACH Act amendments and how do they apply to waters
designated for recreation under a state or tribe's water quality standards? . 16
3.2 How will EPA determine if a state's water quality standards are as protective as
EPA's 1986 water quality criteria for bacteria? 17
3.2.1 Once adopted by a state or authorized tribe into its water quality
standards, how should the water quality criteria for bacteria be used in
beach monitoring and notification programs? • 19
22
References • •
4. Appropriate Approaches for Managing Risk in Recreational Waters 23
4.1 Where should the primary contact recreation use apply? 24
4.1.1 What water quality criteria for bacteria should states and authorized
tribes adopt to protect waters designated for primary contact recreation?
„..,......,....••••• A*
4.1.2 When is it appropriate to adopt seasonal recreational uses? 25
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4.2 What is EPA's policy regarding high levels of indicator organisms from animal
sources? 26
4.3 What is EPA's policy regarding high levels of indicator organisms originating
from environmental sources in tropical climates? 29
4.3.1 Does EPA recommend a different indicator for tropical climates? 29
4.3.2 What options are available to states and authorized tribes to address the
applicability of EPA's recommended water quality criteria for bacteria in
tropical climates? $Q
4.4 What options exist for adopting subcategories of recreation uses? 31
4.4.1 When is it appropriate to modify primary contact recreation uses to reflect
high flow situations? 52
4.4.2 When is it be appropriate to adopt wildlife impacted recreation uses?
••••' ; ....34
4.5 What is EPA's policy regarding secondary contact recreation uses? 37
4.5.1. When is. it appropriate to designate a secondary recreation use? 37
4.5,2 What information should be contained in a use attainability analysis to
remove a primary contact recreation use? 33
4.5.3 What water quality criteria should be applied to waters designated for
secondary contact recreation? 3P
4.5.4 Will EPA publish risk-based water quality criteria to protect for
"secondary contact" uses? 41
References 43
5. Implementation of EPA's Ambient Water Quality Criteria for Bacteria -1986 in State
and Authorized Tribal Water Quality Programs 45
5.1 What is EPA's recommended approach for states and authorized tribes making the
transition from fecal coliforms to E. coli and/or enterococci? 45
5.2 How should states and authorized tribes implement water quality criteria for
bacteria hi their NPDES permitting programs? 46
5.2.1 While transitioning from fecal coliforms to E. coli and/or enterococci, how
should states and authorized tribes implement water quality criteria for
bacteria in their NPDES permitting programs? 46
5.2.2 Once E. coli and/or enterococci have been adopted by states and
authorized tribes, how should the water quality criteria for bacteria be
implemented in NPDES permits ? 47
5.2.3 How do the antibacksliding requirements apply to NPDES permits with
effluent limits for bacteria? 43
5.3 How should state and tribal water quality programs monitor and make attainment
decisions for the water quality criteria for bacteria in recreational waters? 50
5.3.1 While transitioning from fecal coliforms to E. coli and/or enterococci, how
should states and authorized tribes monitor and make attainment
decisions for their water quality criteria for bacteria? SO
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5.3.2 Once E. coli and/or enterococci have been adopted, how should
recreational waters be assessed and attainment determined for waters
where the bacteriological criteria apply? 51
5.4 How should a state or authorized tribe's water quality program calculate allowable
loadings for TMDLs? 56
5.5 What analytical methods should be used to quantify levels of E. coli and
enterococci in ambient water and effluents? 60
5.6 How do the recommendations contained hi this document affect waters designated
for drinking water supply? - 61
5.7 How do the recommendations contained in this document affect waters designated
for shellfishing? 62
f\\
References D0
Appendix A: Beaches Environmental Assessment and Coastal Health Act of 2000 64
Appendix B: Summary of Epidemiological Research Conducted Since 1984 72
Appendix C: Sample Calculations of E. CofcYEnterococci Water Quality Criteria
Associated with Different Risk Levels 82
Appendix D: Summary of Water Quality Criteria for Bacteria Adopted by States,
Authorized Tribes, and Territories • 85
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1. Background and Introduction
In 1986, the U.S. Environmental Protection Agency (EPA) published Ambient Water Quality
Criteria for Bacteria-1986. That document contained EPA's recommended water quality criteria
for bacteria for the protection of bathers from gastrointestinal illness in recreational waters. The
water quality criteria established levels of indicator bacteria, namely Escherichia coli (E. coli) and
enterococci, that demonstrate the presence of fecal pollution and which should not be exceeded in
order to protect bathers in fresh and marine recreational waters. Indicator organisms such as these
have long been used to protect bathers from illnesses that may be contracted from recreational
activities hi surface waters contaminated by fecal pollution. These organisms often do not cause
illness directly, but have demonstrated characteristics that make them good indicators of harmful
pathogens in waterbodies. Prior to its 1986 recommendations, EPA recommended the use of fecal
coliforms as an indicator organism to protect bathers from gastrointestinal illness in recreational
waters. Following epidemiological studies conducted by EPA that evaluated the use of several
organisms as indicators, including fecal coliforms, E. coli, and enterococci, EPA recommended in
1986 the use of E. coli for fresh recreational waters and enterococci for fresh and marine recreational
waters because they were better-predictors of acute gastrointestinal illness than fecal coliforms.
Some states and authorized tribes have replaced their fecal coliform criteria with water quality
criteria for E. coli and/or enterococci; however, many other states and authorized tribes have not yet
made this transition.
The main route of exposure to illness-causing organisms in recreational beach waters is
through direct contact with polluted water while swimming, most commonly through accidental
ingestion of contaminated water, hi waters containing fecal contamination, potentially all of the
waterborne diseases that are spread through fecal contamination and subsequent ingestion (the
"fecal-oral route") may affect bathers. These illnesses result from the following:
Bacterial infection (such as cholera, salmonellosis, shigellosis, and gastroenteritis).
Viral infection (such as infectious hepatitis, gastroenteritis, and intestinal diseases caused by
entero viruses).
Protozoan infections (such as cryptosporidiosis, amoebic dysentery, and giardiasis).
Although the most common effects of bathing in contaminated water are illnesses affecting
the gastrointestinal tract, other illnesses and conditions affecting the eye, ear, skin, and upper
respiratory tract can be contracted as well. With these conditions, infection often results when
pathogenic microorganisms come into contact with small breaks and tears in the skin or ruptures in
delicate membranes in the ear or nose resulting from diving into the water. These illnesses are not
likely to be life-threatening for the majority of the population.
Microorganisms are ubiquitous in all terrestrial and aquatic ecosystems. Many types are
beneficial, functioning as agents for chemical decomposition, food sources for larger animals, and
essential components of the nitrogen cycle and other biogeochemical cycles. Some microorganisms
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reside in the bodies of animals and aid in the digestion of food; others are used for medical purposes
such as providing antibiotics. Of the vast number of species of microorganisms present in the
environment, only a small subset are human pathogens, capable of causing varying degrees of illness
inhumans. While some human pathogens are naturally occurring in the environment (e.g., Naeglaria
or Vibrio cholera), the source of these microorganisms is usually the feces or other wastes of humans
and various other warm-blooded animals. The pathogens most commonly identified and associated
with waterborne diseases can be grouped into the three general categories: bacteria, viruses, and
protozoa.
Bacteria are unicellular organisms that lack an organized nucleus and contain no chlorophyll.
Waste from warm-blooded animals is a source of many types of bacteria found in waterbodies,
including the coliform group and streptococcus, lactobacillus, staphylococcus, and clostridia. It is
important to note, however, that most types of bacteria are not pathogenic.
Viruses are a group of infectious agents that are obligate intracellular parasites (i.e., require a host
in which to live). The most significant virus group affecting water quality and human health
originates in the gastrointestinal tract of infected animals. These enteric viruses are excreted in feces
and include hepatitis A, rotaviruses, Norwalk-type viruses, adenoviruses, enteroviruses, and
reoviruses.
Protozoa are unicellular organisms occurring primarily in the aquatic environment. Pathogenic
protozoa constitute almost 30 percent of the 35,000 known species of protozoans. Pathogenic
protozoa exist in the environment as cysts that hatch, releasing infective forms that attach to or
invade cells, and then grow and multiply, causing associated illness. Encystation of protozoa
facilitates their survival, protecting them from harsh conditions such as high temperature and
salinity. Two protozoa of major concern as waterborne pathogens are Giardia lamblia and
Cryptosporidium parvum.
The detection and enumeration of all pathogens of concern is impractical in most
circumstances due to the potential for many different pathogens to reside in a single waterbody, lack
of readily available and affordable methods, and the variation in likely pathogen concentrations. The
use of indicators provides regulators and water quality managers with a means to ascertain the
likelihood that human pathogens may be present in recreational waters. Specifically, the criteria
published by EPA are intended, once adopted by states and authorized tribes, to control pathogens
by keeping concentrations of indicator organisms at a level that corresponds with acceptable risks
of acute gastrointestinal illness to recreational water users. Of the different illnesses that may be
contracted during recreational activities, gastrointestinal illness occurs most frequently (CDC 2000;
CDC 1998). Gastroenteritis is a term for a variety of diseases that affect the gastrointestinal tract arid
are rarely life-threatening. Symptoms of the illness include vomiting, diarrhea, stomach ache,
nausea, headache, and fever. While other illnesses may be contracted from recreational activities,
they are not specifically addressed by EPA's criteria recommendations. People who become ill as
a result of bathing in contaminated water often do not associate their illness symptoms with
swimming because symptoms often appear several days after exposure and are often not severe
enough to cause individuals to go to the hospital or see a doctor. Most people afflicted by
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gastroenteritis will experience flu-like symptoms several days after exposure, rarely suspecting that
ingestion of water while recreating is the cause of their illness and often assuming that the symptoms
are a result of the flu or food poisoning. Consequently, disease outbreaks often are inconsistently
detected and reported, leading to difficulty in ascertaining the total incidences of illness resulting
from contact with recreational waters.
1.1 What is the purpose of this guidance?
This guidance provides recommendations to help states1 and authorized tribes2 implement
EPA's recommended water quality criteria for bacteria for the protection of recreational waters.
EPA strongly encourages states and authorized tribes that have not already done so, to adopt the
recommendations set forth in Ambient Water Quality Criteria for Bacteria - 1986 or to adopt other
scientifically defensible water quality criteria for bacteria into their recreational water quality
standards to replace fecal or total coliform criteria.
EPA's Ambient Water Quality Criteria for Bacteria-1986 was developed for the protection
of waters designated for recreational uses. Under section 304(a) of the Clean Water Act (CWA),
EPA is required to publish water quality criteria accurately reflecting the latest scientific knowledge
for the protection of human health and aquatic life. The scientific foundation of the criteria is based
on studies conducted by EPA demonstrating that for fresh water, E. coli and enterococci are best
suited for predicting the presence of gastrointestinal illness-causing pathogens, and for marine
waters, enterococci is most appropriate. EPA believes the£. coli and enterococci indicators provide
a better means of protecting recreators from contracting gastrointestinal illness than the use of fecal
coliforms. The transition to E. coli and enterococci bacterial indicators continues to be an Agency
priority for states' and authorized tribes' triennial reviews of water quality standards. Further, the
recently-enacted amendments to the Clean Water Act, also known as the Beaches Environmental
Assessment and Coastal Health Act (BEACH Act amendments), require coastal and Great Lakes
states, by April 2004, to adopt EPA's recommended water quality criteria for bacteria or other
criteria for pathogens or pathogen indicators demonstrated to be as protective as EPA's recom-
mended water quality criteria for Great Lakes, marine, and estuarine waters. The BEACH Act
amendments further direct EPA to propose and promulgate such standards for states that fail to do
so. Appendix A contains the full text of the Beach Act.
'Note: The term "states" will be used to denote states and U.S. territories.
2Pursuant to section 518(e) of the CWA, EPA is authorized to treat an Indian tribe in the same manner as a
state for the purposes of administering a water quality standards program. 40 CFR 131.8 establishes the criteria by
which the Agency makes such a determination. At this time, 23 tribes have requested and been granted program
authorization, and 20 tribes have adopted, and EPA has approved, water quality standards pursuant to section 303(c)
of the Act, and the implementing federal regulations at 40 CFR 131.
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1.2 Why is EPA publishing this guidance?
Despite EPA's and other studies (see Appendix B) demonstrating better correlation between
swimming-associated illnesses and concentrations of E. coli and enterococci, many states and
authorized tribes continue to use either fecal or total coliform criteria to protect and maintain
waterbodies designated for recreation. To date, only 18 states, 3 territories, and 6 authorized tribes3
have adopted E. coli and/or enterococci criteria to protect all or part of their waters designated for
recreation within their jurisdiction (Appendix C). EPA recognizes there has been some uncertainty
among states and authorized tribes with regard to how EPA's recommended 1986 bacteriological
water quality criteria should be implemented and how the transition should be made from fecal
coliforms to E. coli and enterococci. This guidance addresses those issues identified by states and
authorized tribes as impeding their progress toward adopting and implementing EPA's current
recommended water quality criteria for bacteria. To assist states and authorized tribes in the
adoption and implementation of EPA's recommended water quality criteria for bacteria, this
document includes the following:
• Section 2 contains a reaffirmation of the scientific validity of the Ambient Water Quality
Criteria for Bacteria-\ 986 through a summarization EPA's review of relevant peer-reviewed
epidemiological studies conducted since EPA's 1984 epidemiological studies;
• Section 3 contains an explanation of the relationship among state and tribal water quality
standards, the requirements of the BEACH Act amendments, and state and authorized tribal
beach monitoring and advisory programs;
• Sections 4.2 and 4.4 contain recommendations on the application of EPA's recommended
water quality criteria to waters contaminated by non-human sources;
• Section 4.3 provides recommendations for appropriate approaches for monitoring the safety
of recreational waters in those tropical climates where E. coli and enterococci may exist
naturally in the soil environment, possibly complicating the use of those organisms as
indicators;
• Sections 4.4 and 4.5 pro vide recommendations for appropriate approaches for managing risk
in waters that are not designated for primary contact recreation, including waters impacted
The states of Arizona, California, Colorado, Connecticut, Delaware, Hawaii, Idaho, Indiana, Maine,
Michigan, New Hampshire, New Jersey, Ohio, Oklahoma, Oregon, Tennessee, Texas, and Vermont; the territories of
American Samoa, Commonwealth of the Northern Mariana Islands, and Puerto Rico; and the tribes of the Acoma
Pueblo, the Colville Confederated Tribes, the Confederated Tribes of the Umatilla Indian Reservation of Oregon, the
Fond du Lac Band of Lake Superior Chippewa, the Ft. Peck Assiniboine and Sioux Tribes, and the Warm Springs
Tribe have adopted water quality criteria for bacteria based on E. coli and/or enterococci to protect part or all of their
recreational waters. In some cases, because the jurisdiction over bathing beaches and administration of the state's
water quality standards often resides with different departments or at different levels of government (i.e., state versus
county), EPA's recommended water quality criteria may be used to manage beaches even though the state has not
adopted the criteria into its water quality standards.
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by wildlife sources of fecal pollution or high levels of indicator organisms during wet
weather events;
Section 5.1 contains recommendations for making the transition from fecal coliforms to
EPA's recommended water quality criteria, including the use of multiple indicators during
a transition period;
Section 5.4 contains recommendations on the development of wasteload allocations for the
purpose of calculating Total Maximum Daily Loads;
Section 5.5 provides recommendations for the use of detection and enumeration methods in
monitoring ambient and effluent water quality; and
Sections 5.6 and 5.7 discuss the relationship of recommendations contained in this document
to the protection of drinking water sources and shellfishing waters, respectively.
1.3 Who should use this guidance?
This guidance should be used by state and authorized tribal environmental agencies
administering a water quality standards program. This guidance may also provide useful information
for state, tribal, and local beach program managers and interested members of the public.
1.4 What are EPA's recommended water quality criteria for bacteria?
The tables in Appendix D contain EPA's recommended water quality criteria for the
protection of primary contact recreation. The criteria consist of geometric mean and single sample
maximum bacteria density value components derived from specific illness rates. When the criteria
were published in 1986, they were based upon specified illness rates for fresh and marine
recreational waters. Specific single sample maximum values were derived using percentiles (referred
to as "confidence levels" in the criteria document) associated with the geometric mean and observed
standard deviation and were given descriptive headings based on the suggested application of the
maximum values to varying use intensities.
EPA's criteria recommendations include single sample maximum values targeted to various
percentiles at the upper range of the observed distribution. In terms of criteria setting, the targeted
level of protection is the illness rate, and the most direct relationship between measurements of
bacterial levels and illness rate is the geometric mean of measurements taken over the course of a
recreation season. The best way to interpret a series of measurements taken over a period of time
is in comparison to the geometric mean, and the best way to interpret any single measurement is in
comparison to the confidence level associated with the distribution around the geometric mean.
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When EPA published its criteria in 1986, illness rates were established based on 8 illnesses I
per 1000 swimmers in fresh waters and 19 illnesses per 1000 in marine waters, an approximation
of the protection previously afforded by the fecal coliform criterion. In this guidance EPA has
determined that it would be appropriate for states and authorized tribes to protect marine waters at
approximately the same level as fresh waters. This could entail adopting or retaining a fresh water
criterion at a level based on 8 illnesses per 1000 swimmers and adopting a criterion for marine
recreational waters at the same illness rate. Alternatively, a state or authorized tribe may elect to
choose criteria associated with other illness rates to apply to both its fresh and marine recreational
waters. While, in theory, states and authorized tribes could adopt criteria for both fresh and marine
recreational waters associated with illness rates of up to 19 illnesses per 1000 swimmers to protect
its waters designated for primary contact recreation (consistent with EPA's 1986 recommendations
for marine waters) states and authorized tribes should be aware that the epidemiological data used
to support the relationship between illness rates and fresh water bacteriological conditions is based
on an observed illness rate range of up to 14 illnesses per 1000 swimmers, and thus, does not support
extrapolation beyond that point. Consequently, EPA recommends that for states and authorized
tribes choosing to adopt fresh and marine water criteria based on approximately the same illness
rates, the criteria be based on illness rates below 14 illnesses per 1000 swimmers. In any case, for
marine recreational waters, EPA recommends states and authorized tribes adopt criteria associated
with 19 or fewer illnesses per 1000 swimmers for the protection of primary contact recreation waters.
Further discussion on this topic is contained in section 4.1.1.
1.5 What is the basis for EPA's 1986 water quality criteria for bacteria?
Prior to publishing its recommended criteria in 1986, EPA conducted a series of
epidemiological studies that examined the relationship between swimming-associated illness
(namely, acute gastrointestinal illness) and the microbiological quality of the waters used by
recreational bathers. The results of those studies demonstrated that fecal coliforms, the indicator
originally recommended in 1968 by the Federal Water Pollution Control Administration of the
Department of the Interior, are correlated less strongly with swimming-associated gastroenteritis than
other possible indicator organisms. Two indicator organisms, E. coli and enterococci, exhibited a
strong correlation to swimming-associated gastroenteritis, the former in fresh waters only and the
latter in both fresh and marine waters (USEPA, 1986; USEPA, 1984; USEPA, 1983). The strong
correlation maybe due to the indicator organisms being more similar to the pathogens of concern
in their ability to survive within the environment. In some cases, fecal coliforms are routinely
detected where fecal contamination is absent, possibly resulting in inaccurate assessments of
recreational safety. For example, Klebsiella spp., a bacterial organism that is part of the fecal
coliform group and are generally not harmful to humans, are often present in pulp and paper and
textile mill effluents (Archibald, 2000; Dufour et al., 1973). hi contrast, E. coli and enterococci are
less frequently found in environments where fecal contamination is known to be absent, making
them more suitable as indicators of fecal contamination. Enterococci are also resistant to
environmental factors, particularly saline environments, enhancing their utility as an indicator in
marine waters.
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Based on these studies, EP'A''s Ambient Water Quality Criteria for Bacteria - 1986, published
under section 304(a) of the CWA, recommended the use of criteria based on the indicator organisms
E. coli and enterococci rather than fecal coliforms.
1.5.1 How were EPA's epidemiological studies conducted?
The data supporting the water quality criteria were obtained from a series of studies (USEP A,
1984; USEP A, 1983) conducted by EPA examining the relationships between swimming-associated
illness and the microbiological quality of waters used by recreational bathers. The EPA studies were
unique at the time they were initiated because they attempted to relate swimmer illness to water
quality at the time of swimming. This was done by approaching individuals as they were leaving
the beach and asking if they would volunteer to be a part of the recreational water studies.
Individuals who had been swimming during the previous week were excluded from the study. After
seven to 10 days, the volunteers were contacted by telephone to determine their health status since
the swimming event. Control non-swimmers, usually a member of the volunteer's family, were
questioned in a similar manner. The water quality was measured on the day the volunteers swam.
Multiple potential indicators were measured in each beach water sample. Multiple indicators were
measured because it was unknown which one would best correlate to swimmer illness. The
swimming-associated illness parameter was obtained by subtracting the non-swimmer illness rate
from the swimmer illness rate using data collected over a summer trial. Additional study details may
be obtained from Health Effects Criteria for Marine Recreational Waters (USEP A, 1983), Health
Effects Criteria for Fresh Recreational Waters (USEP A, 1984), and the subsequent Ambient Water
Quality Criteria for Bacteria-l 986 (USEPA, 1986).
1.5.2 How were the data from EPA's epidemiological studies analyzed to provide
EPA's recommended water quality criteria for bacteria?
These studies were conducted at three marine and two freshwater locations over several
years. Data were collected on the bacteriological water quality and the incidents of gastrointestinal
illness among swimmers as compared to non-swimmers. For the purpose of analysis, the data
collected at each of these sites were grouped by location and then by season. Each season at a beach
was then averaged into one paired data point consisting of an averaged illness rate and a geometric
mean of the observed water quality. These data points were plotted to determine the relationships
between illness rates and average water quality (expressed as a geometric mean). The resulting
linear regression equations were used to calculate recommended geometric mean values at specific
levels of protection (e.g., 8 illnesses per thousand). Using a generalized standard deviation of the
data collected to develop the relationships and assuming a log normal distribution, various
percentiles of the upper ranges of these distributions were calculated and presented as single sample
maximum values.
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EPA recognizes that the single sample maximum values in the 1986 criteria document are
described as "upper confidence levels," however, the statistical equations used to calculate these
values were those used to calculate percentile values. While the resultant maximum values woulc
more appropriately be called 75th percentile values, 82nd percentile values, etc., this document will!
continue to use the historical term "confidence levels" to describe these values to avoid confusion]
As displayed in Appendix D tables, confidence levels were chosen ranging from 75% to 95°/\
and assigned subjective, qualitative descriptions. For example, the most conservative single sample
maximum value was assigned to beach areas because a more conservative approach should be take
in the protection of heavily-used recreational waterbodies. Conceivably, less intensively used areas|
may have the less restrictive single sample limits applied to them. EPA recommends the use of the
single sample maximum value associated with a 75th percentile for beach areas as a more
conservative approach to assuring that the associated geometric mean is not exceeded in those areas|
regularly used for primary contact recreation activities.
The criteria were developed based on exposures incurred during swimming with head!
immersion and are thus intended to be adopted by states and authorized tribes to protect their primary I
contact recreation uses. Other criteria values may be used to protect surface waters that are not I
designated for primary contact recreation; however, such a designation must be supported by a use I
attainability analysis consistent with federal regulations at 40 CFR 131.10(g). See sections 4.4 and |
4.5 for further discussion.
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References
Archibald, F. 2000. The presence of coliform bacteria in Canadian pulp and paper mill water
systems - A cause for concern? Water Qual. Res. J. Canada 35(1): 1-22.
The Centers for Disease Control and Prevention (CDC). 2000. Surveillance for waterborne-disease
outbreaks - United States, 1997-1998, Morbidity and Mortality Weekly Report 49(SS-04):l-35.
The Centers for Disease Control and Prevention (CDC). 1998. Surveillance for waterborne-disease
outbreaks - United States, 1995-1996, Morbidity and Mortality Weekly Report(1998)
47(SS-5):l-33.
Dufour, A.P., V.J. Cabelli, and M.A. Levin. 1973. Occurrence ofKlebsiella species in wastes from
a textile finishing plant. ASM. Abs. E-16. 73rd Annual Meeting.
USEPA, 1999. Action Plan for Beaches and Recreational Waters. U.-S. Environmental Protection
Agency. EPA/600/R-98/079.
USEPA, 1986. Ambient Water Quality Criteria for Bacteria-1986. U.S. Environmental Protection
Agency. EPA-440/5-84-002.
USEPA. 1984. Health Effects Criteria for Fresh Recreational Waters. U.S. Environmental
Protection Agency. EPA-600/1-84-004.
USEPA. 1983. Health Effects Criteria for Marine Recreational Waters. U.S. Environmental
Protection Agency. EPA-600/1-80-031.
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2. Reaffirmation of EPA's Recommended Water Quality Criteria
The following sections describe the scientific rationale underlying EPA's 1986 guidance,
EPA's re-evaluation of its recommended criteria, and subsequent research conducted following
EPA's issuance of the 1986 guidance. The section also describes additional epidemiological
research EPA plans to conduct in the future that may support development of new water quality
criteria for bacteria.
2.1 Does EPA continue to support its Ambient Water Quality Criteria for Bacteria -1986?
EPA reviewed its original studies supporting its recommended 1986 water quality criteria
for bacteria and the literature on epidemiological research studies conducted since EPA performed
its marine and freshwater research studies of swimming-associated health effects. Based on these
reviews, EPA continues to believe that when appropriately applied and implemented, EPA's
recommended water quality criteria for bacteria are protective of human health for acute
gastrointestinal illness.
The epidemiological and statistical methods used to derive EPA's water quality criteria for
bacteria represent a sound scientific rationale. As with all criteria, there are limitations and
uncertainties. Aside from measuring pathogens directly, the use of bacterial indicators provides the
bestknown approach to protecting swimmers against potential waterborne diseases that maybe fecal
in origin. Despite this fact, there are many known limitations of using indicators as the basis for
protective criteria. The criteria published by EPA are targeted toward protecting recreators from
acute gastrointestinal illness and may not provide protection against other waterborne diseases, such
as eye, ear, skin, and upper respiratory infections, nor illnesses that may be transmitted from
swimmer to swimmer. Also, certain subgroups of the population may contract illnesses more readily
than the general population. These subgroups include children, the elderly, and immuno-
compromised individuals. In addition, because pathogens are not being measured directly, the
concentration of pathogens causing acute gastrointestinal illness may not be constant over time and
at different locations relative to the measured concentrations of bacterial indicators. For instance,
depending upon the type of source and the type and number of pathogens contributed by the source
of fecal pollution, the actual number of illnesses realized for a given level of bacteria may be more
or less than the rates observed in EPA's epidemiological studies that formed the basis of the criteria.
On this topic, the Ambient Water Quality Criteria for Bacteria-l 986 stated:
...the major limitations of the criteria are that the observed relationship may not be
valid if the size of the population contributing the fecal wastes becomes too small or
if epidemic conditions are present in a community, hi both cases the pathogen to
indicator ratio, which is approximately constant in a large population becomes
unpredictable and therefore, the criteria may not be reliable under these circum-
stances.
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Lastly, new pathogens and strains of antibiotic resistant bacteria capable of causing gastrointestinal
illness have been identified since EPA's studies were conducted. The introduction of these new
pathogens into the environment may cause a greater number of illnesses to occur at a given level of
indicator organisms.
These uncertainties and limitations demonstrate the need for appropriate implementation
of water quality criteria for bacteria. To assure protection of recreational water users, EPA
recommends:
frequent monitoring of known recreation areas to establish a more complete
database upon which to determine if the waterbody is attaining the water
quality criteria;
assuring that where mixing zones for bacteria are authorized, they do not
impinge upon known primary contact recreation areas; and
• conducting a sanitary survey when higher than normal levels of bacteria are
measured. (See section 4 for additional information on conducting sanitary
surveys.)
hi addition to its re-evaluation of the original studies, EPA reviewed the literature for
epidemiological research studies conducted after EPA performed its marine and freshwater studies
of swimming-associated health effects. The review examined recent studies to determine if EPA's
indicator relationship findings were supported or if different indicator bacteria were consistently
shown to have quantitatively better predictive abilities. EPA's Office of Research and Development
reviewed 11 separate peer-reviewed studies. This detailed review is contained in Appendix B.
Following this review, EPA's Office of Research and Development concluded:
The epidemiological studies conducted since 1984, which examined the relationships
between water quality and swimming-associated health effects, have not established
any new or unique principles that might significantly affect the current guidance EPA
recommends for maintaining the microbiological safety of marine and freshwater
bathing beaches. Many of the studies have, in fact, confirmed and validated the
findings of the U.S. EPA studies. There would appear to be no good reason for
modifying the Agency's current guidance for recreational waters at this time (Dufour,
1999).
As a result of this examination, EPA believes its 1986 water quality criteria for bacteria
continue to represent the best available science and serve as a defensible foundation for protecting
public health in recreational waters. EPA has no new scientific information or data justifying a
revision of the Agency's recommended 1986 water quality criteria for bacteria at this time. EPA
continues to believe that when appropriately applied and implemented, EPA's recommended
Ambient Water Quality Criteria for Bacteria-1986 are protective of human health for acute
gastrointestinal illness.
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2.2 Have subsequent studies affected EPA's recommended water quality criteria for
bacteria?
None of the epidemiological studies examined by EPA in its recent review presented
compelling evidence that necessitate revising the 1986 water quality criteria for bacteria
recommended by EPA. Most of the studies used a survey plan similar to that used by EPA in the
Agency's studies during the 1970's and 1980's. The study sites chosen by most of the investigators
were similar to those studied by EPA. In the studies, one site was typically a beach with some fecal
contamination, and the other site was usually a relatively unpolluted beach. Most of the bacteria
loadings at the polluted beach sites came from known point sources. The results from these studies
were similar to those found in the EPA studies, i.e., swimming in fecally contaminated water was
associated with a higher rate of gastrointestinal illnesses in swimmers when compared to non-
swimmers. This outcome was not observed in two of the reviewed studies. The reason for a
negative finding is unclear, but could be related to'factors such as the short length of time between
the swimming event and the follow-up contact, the small numbers of children in the study groups,
or the selection of a study site in which the pollution source was poorly defined.
Only a limited number of studies attempted to show a dose-response relationship between
swimming water quality and gastrointestinal illness. Six of the studies (McBride et al., 1998; Kay
et al., 1994; Cheung et al., 1990; Ferley et al., 1989; Seyfried et al., 1985) showed that as the level
of pollution increased, there was also an increase in swimming-associated illness. Only two studies
that looked for a relationship between swimming-associated illness and the level of water quality
failed to find such a relationship (Kueh et al., 1995; Corbett et al., 1993). It is possible that these
findings were related to the indicator organisms measured (i.e., fecal coliforms and fecal
streptococci) or to the methodology used to detect the indicators. In general, the result of these
studies was similar to the results found in the EPA studies; the swimming-associated illness rate
increased with increasing water pollution levels.
It has been shown that some indicator organisms are superior predictors of gastrointestinal
illness in swimmers. In the EPA studies, E. coli and enterococci exhibited the strongest relationships
to swimming-associated gastrointestinal illness. Some of the studies reviewed describe other
microbes having strong relationships with swimming-associated gastrointestinal illness, such as
staphylococci (Seyfried et al., 1985), Clostridium perfringens (Kueh et al., 1995), and Aeromonas
spp. (Kueh et al., 1995). Most of the studies, however, had findings similar to those of the EPA
studies in which enterococci were shown to be the most efficient indicators for measuring marine
water quality. One of the two fresh water studies indicated that E. coli and enterococci both
exhibited very strong correlations with swimming-associated gastrointestinal illness, hi general, the
best indicator organisms for measuring water quality in the reviewed studies were E. coli and
enterococci, results similar to those documented in EPA's studies.
In examining the relationships between water quality and swimming-associated gastro-
intestinal illness, the epidemiological studies conducted since 1984 offer no new or unique principles
that significantly affect the current water quality criteria EPA recommends for protecting and
maintaining recreational uses of marine and fresh waters. Many of the studies have, in fact,
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confirmed and validated the findings of EPA's studies. Thus, EPA has no new scientific information
or data justifying a revision of the Agency's recommended 1986 water quality criteria for bacteria
at this time.
2.3 Is EPA planning on conducting additional epidemiological studies in the future?
The recently enacted Beaches Environmental Assessment and Costal Health (BEACH) Act
amendments to the Clean Water Act require EPA to perform an assessment of potential human
health risks resulting from exposure to pathogens in coastal recreation waters. To meet this
requirement, EPA is planning to conduct additional epidemiological studies that maybe used to
revise and develop new water quality criteria for pathogens and pathogen indicators. See CWA
§§104, 304(a) (33 U.S.C. 1254; 33 U.S.C. 1314). Section 3 contains more information on the
BEACH Act of 2000.and EPA's BEACH program. Appendix A contains the full text of the BEACH
Act.
Future epidemiological studies and evaluation of new indicators and methods may provide
new information to support protection of recreation waters. EPA plans to conduct epidemiological
studies to support the development of new water quality indicators and associated guidelines for
recreational waters. The epidemiological studies will examine the illness rates in families with
children as they relate to microbial contaminant levels in fresh and marine recreational waters. The
studies will evaluate exposure to and effects of illness from microbial pathogens in recreational
waters. A range of water quality indicators will be monitored in fresh and marine recreational
waters. The specific indicators that will be used have not been determined at this time. Recreational
waters included in the study will be selected based on potential number of beach-goers, water
quality, and sources of microbial pathogens to the water (domestic sewage versus animals). Pilot
studies are scheduled to begin in summer 2002, with full-scale studies being completed by the end
of the 2006 fiscal year. Pending their results, new criteria for the protection of recreation waters may
be developed following the completion of these studies.
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References
Cheung, W.H.S., K.C.K. Chang, and R.P.S. Hung. 1990. Health effects of beach water pollution
in Hong Kong. Epidemiol. Infect. 105:139-162.
Corbett, S.J., J.L. Rubin, O.K. Curry, and D.G. Kleinbaum. 1993. The health effects of swimming
at Sydney beaches. Am. J. Public Health 83-1701-1706.
Dufour, Alfred P. March 16,1999. Memo from Alfred P. Dufour, Director, Microbiological and
Chemical Exposure Assessment Research Division, Office of Research and Development to ••
Elizabeth Southerland, Acting Director, Standards and Applied Sciences Division, Office of Water,
U.S. Environmental Protection Agency.
Ferley, J.P., D. Zmirou, F. Balducci, B. Baleux, P. Fera, G. Larbaigt, E. Jacq, B. Moissonnier, A.
Blineau, and J. Boudot. 1989. Epidemiological significance of microbiological pollution criteria
for river recreational waters. Int. J. of Epidemiol. 18:198-205.
Haile, R.W., J.S. Witte, M. Gold, R. Cressey, C. McGee, R.C. Millikan, A. Glasser, N. Harawa, C.
Ervin, P. Harmon, J. Harper, J. Derrnand, J. Alamillo, K. Barrett, M. Nides, and G. Wang. 1999.
The health effects of swimming in ocean water contaminated by storm drain runoff, Epidemiol
10:355-363.
Kay, D., J.M. Fleisher, R.L. Salmon, F. Jones, M.D. Wyer, S.F. Godfree, Z. Zelenauch-Jacquotte,
and R. Shore. 1994. Predicting likelihood of gastroenteritis from sea bathing: Results from
randomized exposure. Lancet 344:905-909.
Kueh, C.S.W., T-Y Tarn, T.W. Lee, S.L. Wang, OX. Lloyd, I.T.S. Yu, T.W. Wang, J.S. Tarn, and
D.C. J. Bassett. 1995. Epidemiological study of swimming-associated illnesses relating to bathing-
beach water quality. Wat. Sci Tech. 31:1-4.
McBride, G.B., C.E. Salmond, D.R. Bandaranayake, SJ. Turner, G.D. Lewis, and D.G. Till. 1998.
Health effects of m'arine bathing in New Zealand, hit. J. of Environ. Health Res. 8:173-189.
Seyfried, P.L., R.S. Tobin, N.E. Brown, and P.F. Ness. 1985. A prospective study of swimming-
related illness JJ. Morbidity and the Microbiological Quality of Water. Am. J. Public Health 75-
1071-1075.
USEPA, 1986. Ambient Water Quality Criteria for Bacteria-1986. U.S. Environmental Protection
Agency, Washington, DC. EPA-440/5-84-002.
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3. Relationship Between Water Quality Standards and Beach Monitoring and Advisory
Programs
CWA §303 requires states and authorized tribes to adopt water quality standards for waters
of the United States within their jurisdiction sufficient to "protect the public health or welfare,
enhance the quality of water and serve the purposes of [the CWA] ." EPA has an oversight role in
this process. EPA's implementing regulations at 40 CFR 131.11 require water quality criteria to be
based on sound scientific rationale and to contain sufficient parameters to protect designated uses.
Further, section 303(c) specifies that water quality standards shall include the designated use or uses
to be made of the water and water quality criteria necessary to protect those uses. States and
authorized tribes may adopt water quality criteria based on EPA's recommended water quality
criteria developed under section 304(a) of the CWA or other scientifically defensible methods.
Within the context of this guidance, states and authorized tribes may adopt EPA's recommended
water quality criteria for bacteria, or other water quality criteria for bacteria based on scientifically
defensible methods, to protect those waterbodies designated for primary contact recreation.
EPA's current 304(a) criteria are used as the basis for Agency decisions, both regulatory and
nonregulatory, until EPA revises and reissues pollutant-specific 304(a) criteria. Two distinct
purposes are served by the 304(a) criteria: (1) as guidance to states and authorized tribes in the
development and adoption of water quality criteria which will protect designated uses, and (2) as the
basis for promulgation of a superseding federal rule when such action is necessary. Once adopted
by a state or authorized tribe into their water quality standards or promulgated by EPA for a state or
authorized tribe, the water quality criteria are used to establish National Pollutant Discharge
Elimination System (NPDES) water quality-based permit limits, to assess the attainment of water
quality, and to provide the basis upon which Total Maximum Daily Loads (TMDLs) are developed.4
hi addition to the uses for the state or tribal-adopted water quality criteria for bacteria listed
above, some beach monitoring and advisory programs have used the state or .authorized tribe's
bacteriological criteria adopted into the state's or authorized tribe's water quality standards to issue
beach advisories and make opening and closure decisions for identified beach areas, hi general,
waters designated for primary contact recreation within a state or authorized tribe's water quality
standards comprise a much larger group of waterbodies than those falling under the purview of a
state or tribe ' s beach program. While waters designated for primary contact recreation may consist
of a majority of a state or tribe's waters and may vary in type from remote streams to well-known
and highly managed beach areas, beach programs generally focus on the latter subset. EPA
recommends beach programs use the state or tribal-adopted water quality standards for beach
advisories (a requirement for those beaches covered under the BEACH Act) and encourages
coordination between state and tribal water quality standards programs and beach monitoring and
advisory programs.
4After a waterbody has been placed on a list by a state or authorized tribe for not attaining its water quality
standards, a TMDL, which is an analysis apportioning pollutant loads to sources of the pollutant causing the
impairment, is usually developed.
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Although these natural relationships exist between water quality standards and beach
monitoring and advisory programs, the use of bacterial water quality monitoring data as part of beach
monitoring and advisory programs may differ slightly to account for some of the inherent differences
between the two programs. For example, because a beach manager must make decisions based on
water quality on a given day or weekend, he or she may focus more on recently collected data to
determine whether a swimming advisory should be issued. This contrasts with the use of monitoring
data for making a determination that a waterbody is not attaining water quality standards as specified
under CWA §303(d). In this case, states and authorized tribes will usually consider data collected
over a longer period of time. Further, for beach programs, beach managers may wish to consider
other types of data hi addition to water quality data. This may include the consideration of rainfall
data when notifying the public that the standards have been exceeded or are expected to be exceeded.
A recent EPA-funded study in Massachusetts at Boston Harbor beaches found that because the time
necessary to obtain water quality monitoring results is at least 24 hours, levels of enterococci
measured on the previous day were not always predictive of the water quality that existed when the
monitoring results became available. The study found that using water quality data in conjunction
with rainfall data as the basis for posting swimming advisories resulted in more accurate postings
and fewer occasions when a swimming advisory would have otherwise been issued based on poor
water quality associated with a previous day's measurements (MWRA, 2001).
EPA understands that the authority for administering beach programs varies among states and
tribes and may rest with state, tribal, county, or municipal government. When the governmental
body with the responsibility and authority for a beach monitoring and advisory program differs from
the state or tribe's water quality standards program, EPA encourages coordination of these programs
to ensure the greatest efficiency and consistency in monitoring and data collection. Additional
information on the use of EPA's recommended criteria for bacteria in beach monitoring and
notification programs will be found in EPA's National Beach Guidance and Required Performance
Criteria for Grants, which is expected to be made available to the public in June 2002.
3.1 What are the BEACH Act amendments and how do they apply to waters designated for
recreation under a state or tribe's water quality standards?
On October 10, 2000, the Beaches Environmental Assessment and Coastal Health Act
(BEACH Act) was passed, amending the Clean Water Act to provide for monitoring of coastal
recreation waters and public notification when the applicable water quality standards are not met or
are not expected to be met. As defined by the Act, coastal recreation waters are the marine, coastal
estuaries, and Great Lakes waters. The amendments contain three significant provisions,
summarized as follows:
1. The BEACH Act amended the CWA to include section 3 03(i), which requires states
that have coastal recreation waters to adopt new or revised water quality standards
by April 10,2004, for pathogens and pathogen indicators that are as protective as the
criteria published by EPA under CWA section 3 04(a). SeeCWA §303(i)(l)(A). The
BEACH Act amendments further direct EPA to promulgate such standards for states
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that fail to do so. See CWA §303(i)(2)(A). For those states that have not adopted
water quality standards as protective as EPA's water quality criteria, EPA intends to
publish an Advance Notice of Proposed Rulemaking identifying those states not
adopting such criteria prior to its proposing federal water quality standards.
The BEACH Act amended the CWA to require EPA to study issues associated with
pathogens and human health and, by October 10, 2005, to publish new or revised
CWA section 304(a) criteria for pathogens and pathogen indicators based on these
studies. See CWA §104(v). Within 3 years after EPA's publication of the new or
revised section 304(a) criteria, states that have coastal recreation waters must then
adopt new or revised water quality standards for all pathogens and pathogen
indicators to which EPA's new or revised section 304(a) criteria apply. See CWA
§303(i)(l)(B).
The BEACH Act amended the CWA to include a new section, section 406, which
authorizes EPA to award grants to states and authorized tribes for the purpose of
developing and implementing a program to monitor for pathc-gens and pathogen
indicators in coastal recreation waters adjacent to beaches that are used by'the public
and to notify the public if water quality standards for pathogens and pathogen
indicators are exceeded or likely to be exceeded. To be eligible for the implemen-
tation grants, states and authorized tribes must develop monitoring and notification
programs that are consistent with performance criteria published by EPA under the
Act. This performance criteria is contained in EPA's National Beach Guidance and
Required Performance Criteria for Grants. Development grants were made
available to all eligible states in 2001, and will be made available again in 2002. The
BEACH Act also requires EPA to perform monitoring and notification activities for
waters in states that do not have a program consistent with EPA's performance
criteria, using grants funds that would otherwise have been available to those states.
See CWA §406(h). For the full text of the BEACH Act, see Appendix A.
3.2 How will EPA determine if a state's water quality standards are as protective as EPA's
1986 water quality criteria for bacteria?
In determining whether a state's water quality standards are as protective as EPA's 1986
water quality criteria for bacteria for BEACH Act purposes, it is useful to review the development
and analyses supporting the criteria. This analysis also applies to situations outside the context of
the BEACH Act in evaluating and adopting the appropriate criteria to protect primary contact
recreation uses. The water quality criteria for bacteria recommended by EPA consist of two
elements: a geometric mean value and a single sample maximum. For each geometric mean value,
four different single sample maximum values were developed based on the distribution of the
observed data (See tables contained in Appendix C). These range from the 75% to the 95%
confidence levels.
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As discussed in section 1.5.2, the single maximum values calculated are more appropriately
referred to as percentiles based on the equations used. The term "confidence levels" has been
retained to avoid confusion; however, the manner in which the maximum values were derived has
implications for the implementation of the criteria. Percentiles represent the predicted bounds of
values surrounding the geometric mean. For example, 95 percent of the values used in calculating
the recommended geometric means fell under the 95th percentile value, with only 5% of the values
falling above the 95th percentile value. Likewise, 75 percent of the values used in calculating the
recommended geometric mean fell below the 75th percentile value, with 25% of the values falling
above the upper 75th percentile value. The percentile values are based on a standard deviation and
an assumption of log normal shape of the distribution. In terms of statistics, a measurement falling
above the 75th percentile value of the collected data is somewhat likely to lie beyond the distribution
of values that constitute the geometric mean, whereas a measurement that falls above the 95th
percentile value is very likely to lie beyond the distribution of values that constitute the geometric
mean.
In terms of risk management, selecting a lower confidence level (e.g., 75%) for comparison
to single measurements will result in a more conservative estimate of whether the measurement is
associated with a given geometric mean value. This would result in a greater number of "false
positive" determinations (i.e., bias toward concluding that criteria are not attained). In the case of
beach advisories, this more conservative approach maybe warranted. In contrast, selecting a higher
confidence level (e.g., 95%) for comparison to single measurements will result in a less conservative
estimate of whether the measurement is associated with a given geometric mean value. This would
result in a fewer number of "false positive" determinations. EPA considers the range of the 75% to
95% confidence levels to represent an appropriate balance between "false positives" and "false
negatives" for determining attainment of a geometric mean associated with a given illness rate.
Both the selection of a target illness rate within a certain range and the choice of a specific
single sample maximum value within this range is a risk management decision at the discretion of
the state or authorized tribe. In practice, the choice of a single sample maximum depends on several
considerations, including the degree of confidence that the variability associated with the standard
deviation accurately reflects the variability at the site [i.e., if the site (or group of recreational waters)
exhibits enormous variability in bacteria levels, then a lower confidence level (e.g., 75%) maybe
more appropriate, at least until a site-specific standard deviation is determined]. Another important
consideration is the consequence of the decision (e.g., the potential for more illnesses versus the loss
of recreational use resulting from a beach advisory or closure). The table of single sample maximum
values presented in the 1986 criteria document includes qualitative descriptors of beach usage
associated with different confidence levels. This represents one approach to risk management, one
that reflects a strong bias toward avoiding the potential for greater numbers of illnesses at more
heavily used recreational waters.
EPA will consider a state's water quality standards to be as protective as its recommendations
consistent with the requirements in CWA §303(i)(l)(A) applying to coastal and Great Lakes states
if, for fresh waters, the state's criteria are
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-1. based on an illness rate equal to or less than 14 illnesses per 1000; and
2. uses a geometric mean and a single sample maximum;
and if, for marine waters, the state's criteria are
1. based on an illness rate equal to or less than 19 illnesses per 1000; and
2. uses a geometric mean and a single sample maximum value.
In either case, EPA would not consider a single sample maximum adopted exceeding the value
associated with the 95% confidence level value to be as protective as its recommendations. EPA
would also consider such criteria to be protective of primary contact recreation uses for waters not
covered under the BEACH Act.
EPA recommends states and authorized tribes adopt both a geometric mean and single
sample maximum for several reasons. Because the criteria form the basis for several purposes under
the Clean Water Act, adoption of both a geometric mean and a single sample maximum will give
states and authorized tribes the necessary components to best implement their adopted criteria for
water quality-based effluent limits, determine whether a waterbody is attaining its water quality
standards, and issue beach notifications and advisories. In some circumstances, states and authorized
tribes may conclude that after evaluation of their monitoring data for a particular waterbody that,
while the geometric mean is consistently-met, the distribution of water quality data is such that the
single sample maximum values are routinely exceeded. In this case, as described in the Ambient
Water Quality Criteria for Bacteria—1986, a state or authorized tribe may re-calculate a standard
deviation specific to the waterbody and subsequently adopt into water quality standards single
sample maximum values specific to the observed distribution of criteria. For any state or authorized
tribe choosing this option, data used should be sufficient in number and representative of the
waterbody.
3.2.1 Once adopted by a state or authorized tribe into its water quality standards,
how should the water quality criteria for bacteria be used in beach monitoring
and notification programs?
States, authorized tribes, and local governments carrying out beach monitoring and
notification programs under section 406 of the Clean Water Act monitor certain coastal recreation
waters for attainment of applicable water quality standards and notify the public whenever those
standards are exceeded or are likely to be exceeded.5 Assuming that a geometric mean value and a
Note: For states and authorized tribes receiving grants under the BEACH Act, the requirements described
in this section are elements that must be included in a state or authorized tribe's beach monitoring and advisory
program in order to be eligible to receive funding. For other state and tribal beach programs for waters not covered
by the BEACH Act, these provisions should be considered recommendations.
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single sample maximum have been adopted, both measures should be used in making public
notification decisions.
Use of both the geometric mean and single sample maximum will enable beach managers
to better evaluate the overall water quality of their beaches. For example, comparison of water
quality data with the single sample maximum value will provide beach managers with the most
recent information about the water quality of a beach and the information with which to post beach
closings or issue advisories, hi addition, frequent exceedances of the geometric mean will likely
indicate that a chronic contamination problem exists and that a sanitary survey should be conducted
to determine the cause.
When bacteria concentrations exceed an applicable standard, the appropriate agency must
immediately make a decision to either issue a public notification or to resample. A state, tribal, or
local government can resample where there is reason to doubt the accuracy or certainty of the first
sample, based on predefined quality assurance measures. The interpretation of the bacteria
monitoring data with respect to notifying the public of an advisory or closing the beach should be
clear and based on the decision rules established during the state or authorized tribe's planning
process. (For more information, refer to the National Beach Guidance and Required Performance
Criteria for Grants discussion in Section 4.2.1, When to Conduct Additional Sampling.)
EPA's National Beach Guidance and Required Performance Criteria for Grants, also
contains detailed information and recommendations regarding when and how to provide public
notification for beaches covered under the state or authorized tribe's program. EPA recommends
a "tiered" beach classification system in which beaches are sorted into various tiers, depending on
beach risk and/or amount of use. Further, CWA §406 requires states, authorized tribes, and local
governments to prioritize the use of grant funds for monitoring and notification programs based on
the use of the waterbody and the risk to human health presented by pathogens or pathogen indicators.
Thus, "Tier 1" would include those beaches likely to have the greatest risk and/or highest use. Under
this approach, the specific notification actions may be tailored to each category. (These recom-
mendations are taken from Chapter 5 of the National Beach Guidance and Required Performance
Criteria for Grants.)
EPA recommends that a tiered approach be used to determine the sampling frequency for the
designated beaches, hi general, EPA recommends that states, tribes, and local governments monitor
at least once a week at the Tier 1 and Tier 2 beaches, resulting in the calculation of a 30-day
geometric mean based on at least four samples.
Because the BEACH Act requires that states and authorized tribes notify the public whenever
the water quality standards are exceeded or likely to be exceeded, some states, authorized tribes, and
local governments have logically concluded that a situation may arise in which a beach would
continue to be closed or advisories issued after the isolated high bacteria level was observed due to
the continued exceedance of the geometric mean. Since the geometric mean is generally calculated
based on data collected over the previous thirty days, a high bacteria level measured a week or two
earlier could continue to cause the geometric mean value to remain high, even if subsequent samples
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are much lower. However, this type of situation can be prevented in the following ways. First,
states, authorized tribes, and local governments that monitor more frequently than on a weekly basis
will rarely encounter this situation. In areas where regular monitoring occurs less frequently,
monitoring should be conducted as soon as possible after a single, very high sample is detected. If
a state, authorized tribe, or local government has developed a good quality assurance/quality control
plan, requiring the collection of replicate samples would provide the it with further information with
which to assess whether the observed high bacteria level is representative of conditions or is an
"outlier."
EPA has also proposed several ambient water quality monitoring methods for bacteria that
are easily portable and relatively cheap, which should facilitate states', authorized tribes', and local
governments' ability to conduct additional monitoring should the need arise. Additional samples
taken following observance of a single high value will serve the dual purpose of identifying when
the waterbody is safe again and showing that the geometric mean is being met based on increased
sampling frequency.
EPA believes these approaches will meet the BEACH Act requirement that states adopt water
quality standards for their coastal waters "as protective as" EPA's recommendations. In using any
of these approaches, the state will achieve the protection of recreational waterbodies consistent with
EPA's criteria recommendations.
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References
Massachusetts Water Resources Authority (MWRA), prepared by Kelly Coughlin and Ann-Michelle
Stanley. 2001. Water Quality at Four Boston Harbor Beaches: Results of Intensive Monitoring,
1996 - 1999. Boston, MA. US EPA Grant # X991712-01.
USEPA. 2002. National Beach Guidance and Required Performance Criteria for Grants. U.S.
Environmental Protection Agency, Washington, DC. EPA-823- B-02-004
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4. Appropriate Approaches for Managing Risk in Recreational Waters
Recreation occurs in many forms throughout the United States and frequently centers around
waterbodies and activities occurring in and on the water. To protect the public while recreating in
surface waters, states and authorized tribes have adopted primary contact recreation uses and
bacteriological criteria for the majority of waterbodies in the United States. Pursuant to the federal
regulations, primary contact recreation uses must be adopted for waterbodies unless such uses are
shown not to be attainable. Further, primary contact recreation uses must be adopted wherever
necessary to protect such uses downstream. See 40 CFR 131.10(b), 40 CFR 131.10(j).
As highlighted in section 2, states and authorized tribes may help assure protection of
recreational waters through frequent monitoring of known recreation areas to establish a more
complete database upon which to determine if the waterbody is attaining the water quality criteria;
assuring that where mixing zones for bacteria are authorized, they do not impinge upon known
primary contact recreation areas; and conducting sanitary surveys when higher than normal levels
of bacteria are measured.
Sanitary surveys are an important element of protecting recreational waters and have long
been used as a means to identify potential sources of contamination. A sanitary survey is an
examination of a watershed to determine if unauthorized sanitary discharges are occurring from
sources such as failed septic tank leach fields or cesspools, sewage leakage from broken pipes,
sanitary sewer overflows from hydraulically overloaded sewers, or overflows from storm sewers that
may contain illegal sanitary sewer connections. The survey should use available public health and
public works departments' records to identify where such septic tanks and sewer lines exist so that
observations are focused in the right places. A sanitary survey might also use dyes or other tracers
in both dry and wet weather to see if unauthorized discharges are occurring from septic tanks and
sewers. In addition, EPA recommends that sanitary surveys identify other possible sources,
including confined animal areas, wildlife watering points, and recreational spots, such as dog
running/walking areas, since these are also sources of fecal pollution. Additional guidance for
conducting sanitary surveys maybe found from several sources: The National Beach Guidance and
Required Performance Criteria for Grants contains a section discussing the use of sanitary surveys
in recreational waters and contains a summarization of recent publications on the subj ect. Additional
resources include the Guidance Manual for Conducting Sanitary Surveys of Public Water System
(USEPA, 1999), the National Shellfish Sanitation Program Model Ordinance (NSSP, 1999), and
California's Guidance for Saltwater Beaches (draft) and Guidance for Freshyvater Beaches (draft)
(CA DHS, 2000a; CA DHS, 2000b).
Sanitary surveys, in addition to being a tool that can be used to identify sources of
contamination, can provide useful data in characterizing a recreational waterbody and determining
the relative contributions of fecal pollution sources. This type of information can be useful in
deciding how to control sources as well as provide useful information to a state or authorized tribe
that may be contemplating a change to the recreational use. While many waters are suitable for
recreation of some sort, there are circumstances where primary contact recreation may not be
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attainable. This section identifies these situations and provides recommendations to appropriately
protect these waters.
4.1 Where should the primary contact recreation use apply?
States and authorized tribes should designate primary contact recreation and adopt water
quality criteria to support that use, unless shown to be unattainable, to reduce the risk of
gastrointestinal illness in recreators. hi particular, states and authorized tribes should assure that
primary contact recreation uses are designated for waterbodies where people engage, or are likely
to engage, in activities that could result in ingestion of water or immersion. These activities logically
include swimming, water skiing, kayaking, and any other activity where contact and immersion in
the water is likely. However, states and authorized tribes should also be aware that although
conditions such as the location of a waterbody, high or low flows, safety concerns, or other physical
conditions of the waterbody may make it unlikely that these activities would occur, EPA believes
that people, particularly children, may swim or make other use of the waterbody such that ingestion
may occur. Children are more likely to engage in activities where ingestion of water is likely, even
in waterbodies where ingestion would not be likely for adults. Children splash and swim in shallow
waters that may otherwise be considered too shallow for full body immersion. Other populations,
such as kayakers or surfers, may actually seek out high flow or unsafe waters in which to recreate.
4.1.1 What water quality criteria for bacteria should states and authorized tribes
adopt to protect waters designated for primary contact recreation?
In adopting criteria to protect primary contact recreation waters, EPA recommends states and
authorized tribes use enterococci and/or E. coli criteria with a specified illness rate no greater than
14 illnesses per 1000 swimmers for fresh waters and no greater'than 19 illnesses per 1QOO swimmers
for marine waters. These recommendations are contained in Appendix C. In adopting water quality
criteria for bacteria to protect waters designated for primary contact recreation, states and authorized
tribes should adopt both a geometric mean and a single sample maximum using the values or
equations described in Appendix C to calculate the appropriate geometric mean and single sample
maximum values. EPA believes that the objective of protecting primary contact recreation waters
is best achieved through this approach. The rationale behind this recommendation is contained in
section 3.2. For waters that are known to be heavily-used swimming areas and where necessary to
protect downstream primary contact recreation uses, states and authorized tribes should consider
using more conservative approaches, such as adopting criteria based on lower illness rates (e.g., 8
illnesses per 1000 swimmers for fresh waters) or a more conservative single sample maximum (e.g.,
single sample maximum values based on the 75% confidence level). For recommendations on
refining recreation uses for waters where primary contact recreation is not attainable, see section 4.4.
States and authorized tribes that opt to protect primary contact recreation waters with criteria
associated with illness rates within these ranges should recognize that this is a risk management
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decision by the state or authorized tribe similar to the selection of alternate risk levels when adopting
human health criteria for carcinogens, and thus would not require a use attainability analysis as
described by the federal regulations at 40 CFR 131.10. Exercising such discretion should assure,
however, that downstream uses, including downstream uses across state or tribal boundaries, are
protected. Further, like any other addition or revision to a state or authorized tribe's water quality
•standards, any subsequent change resulting from these risk management decisions are subject to the
public participation requirements at 40 CFR 131.20(b).
In utilizing this risk management discretion, states and authorized tribes may wish to
establish more than one category of primary contact recreation use. For example, Colorado has two
categories of primary contact recreation use in addition to their secondary contact recreation
designated use (CDPHE, 2001). The Recreation Class 1A use is the default use category, and is
assigned an E. coli criterion of 126 colony forming units (cfu) per 100 milliliters (ml) based on
EP A's recommended illness rate of 8 illnesses per 1000 swimmers. In these waters, primary contact
recreation uses have been documented or are presumed to be present. The Recreation IB use is
intended to protect waters with the potential to support primary contact recreation uses and may be
assigned only if a reasonable level of inquiry has failed to identify any existing primary contact
recreation uses of the waterbody. This use category is assigned an E. coli criterion of 206 cfu per
100 ml based on an illness rate of 10 illnesses per 1000 swimmers. Finally, under Colorado
regulation, the secondary contact recreation use (known as Recreation Class 2 in the Colorado water
quality standards) may be assigned only where a use attainability analysis has been conducted
consistent with 40 CFR 131.10 that further demonstrates there is no reasonable potential for primary
contact recreation uses to occur within the next 20-year period. This use category is assigned an E.
coli criterion of 630 cfu per 100 ml, which is five times the geometric mean criterion value
associated with 8 illnesses per 1000 swimmers.
4.1.2 When is it appropriate to adopt seasonal recreational uses?
A seasonal recreation use may be appropriate in those states and authorized tribes where
ambient air and water temperatures cool substantially during the winter months. For example, in
many northern areas, primary contact recreation is possible only a few months out of the year.
Several states and authorized tribes have adopted, and EPA has approved, primary contact recreation
uses and the associated microbiological water quality criteria only for those months when primary
contact recreation occurs and have relied on less stringent secondary contact recreation water quality
criteria to protect for incidental exposure in the "non-swimming" season. The federal regulation
allows for seasonal uses, provided the criteria adopted to protect such uses do not preclude the
attainment and maintenance of a more protective use in another season. See 40 CFR 131.10(f).
EPA feels this is an appropriate approach, particularly where treatment of discharges
sufficient to meet the primary contact recreation use would result in the use of disinfection by
chlorine and thus, the release of residual chlorine in the effluent. Total residual chlorine in effluents
discharging to surface waters can react with organic compounds to produce disinfection by-products
such as rrihalomethanes. Trihalomethanes have an adverse impact on human health and aquatic life,
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and are consequently of particular concern in waterbodies used for drinking water and areas where
aquatic life may be adversely impacted. Thus, in some cases states and authorized tribes have
adopted seasonal uses to allow for the reduction or suspension of effluent chlorination during the
colder months and, consequently, to reduce risk to human health and aquatic life.
The rationale provided by states and authorized tribes to EPA to support a change in water
quality standards resulting in adoption of a seasonal recreation use for a waterbody need not be
burdensome. EPA's regulations do not require a formal use attainability analysis for the adoption
of seasonal recreation uses. Generally, for a state or authorized tribe contemplating such a revision
to its recreational water quality standards, EPA would expect that the state or authorized tribe
provide information on why the particular season is being chosen. This information may include
information relating to the times of year when the ambient air and water temperatures support
primary contact recreation, activities in and use (or lack thereof) of the waterbody during the
proposed non-recreation months, and other relevant information.
4.2 What is EPA's policy regarding high levels of indicator organisms from animal
sources?
In the 1994 Water Quality Standards Handbook, EPA established a policy that states and
authorized tribes may apply water quality criteria for bacteria to waterbodies designated for
recreation with the rebuttable presumption that the indicators show the presence of human fecal
contamination. As noted below, EPA is now revising this policy. This 1994 policy stated:
States may apply bacteriological criteria sufficient to support primary contact
recreation with a rebuttable presumption that the indicators show the presence of
human fecal pollution. Rebuttal of this presumption, however, must be based on a
sanitary survey that demonstrates a lack of contamination from human sources. The
basis for this option is the absence of data demonstrating a relationship between high
densities of bacteriological water quality indicators and increased risk of swimming-
associated illness hi animal-contaminated waters.
In short, under this policy a state or authorized tribe could justify a decision not to apply the criteria
to a particular waterbody when bacterial indicators were found to be of animal origin. This policy
was based on the absence of data correlating non-human sources of fecal contamination and human
illness and on the belief that pathogens originating from animal sources present an insignificant risk
of acute gastrointestinal illness in humans.
EPA no longer believes that the position taken in the 1994 Water Quality Standards
Handbook is supported by the available scientific data. The available data suggest that there is some
risk posed to humans as a result of exposure to microorganisms resulting from non-human fecal
contamination. As a result, states and authorized tribes may no longer use broad exemptions from
the bacteriological criteria for waters designated for primary contact recreation based on the
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presumption that high levels of bacteria resulting from non-human fecal contamination present no
risk to human health. .
Recent evidence indicates that warm-blooded animals other than humans maybe responsible
for transmitting pathogens capable of causing illness in humans. Examples include outbreaks of
enterohemorrhagic E. coli 0157:H7, Salmonella, Giardia, and Cryptosporidium, all of which are
frequently of animal origin. Consequently, due to the potential for animal sources to contribute
human pathogens to surface waters, EPA is changing its 1994 policy as stated in the Water Quality
Standards Handbook through this guidance to recommend that states and authorized tribes apply
their water quality criteria for bacteria to all waterbodies designated for primary contact recreation
in order to ensure protection of human health from gastrointestinal illness. Livestock, wildlife, and
domestic pets are carriers of human pathogens and can transmit these pathogens to surface waters
as well as contribute significant numbers of indicator bacteria to waterbodies. The relative health
risk from waters contaminated by human sources versus non-human sources has been the subject of
recent debate, particularly related to the application and implementation of EPA's recommended
water quality criteria for bacteria. Blanket exemptions for animal sources would not ensure
protection of swimmers in waters designated for primary contact recreation.
Incidents where these pathogens have been spread to humans through water have been
documented in recent years. In the case of E. coli O157:H7, several cases have been cited in which
fecal contamination from animals was the probable source of the pathogen. The most prominent
examples have included contamination of water supplies, including an outbreak in Alpine,
Wyoming, in June 1998, affecting 157 people, and a major outbreak Walkerton, Ontario, in May and
June of 2000 causing more than 2,300 people to become ill and causing seven deaths (CDC, 2002;
CDC, 2000; Ontario's Ministry of the Attorney General, 2000). m the former case, contamination
by wildlife of the community water supply is the suspected source, and in Walkerton, Ontario, heavy
rains causing agricultural runoff to leak into city wells is suspected. The 1993 Milwaukee
Cryptosporidium outbreak is a well-known example of water supply contamination that resulted in
403,000 illnesses and approximately 100 deaths. The source of the oocysts was not identified, but
suspected sources include agricultural runoff from dairies in the region, wastewater from a
slaughterhouse and meat packing plant, and municipal wastewater treatment plant effluent (Gasman,
1996; USD A, 1993). In addition, Cryptosporidium was the known cause of 15 other outbreaks
associated with drinking and recreational water affecting 5,040 individuals in the U.S. between 1991
and 1994 (Gibson et al., 1998). While many of the reported outbreaks have occurred through the
consumption of contaminated drinking water, other incidences of E. coli O157:H7 infection from
exposure to surface waters have been documented. For example, in the summer of 1991,21 E. coli
O157:H7 infections were traced to fecal contamination of a lake where people swam in Portland,
Oregon (Keene et al., 1994)
These and other pathogens can cause significant gastrointestinal illness, although direct
measurement of these organisms is not readily quantified by current conventional microbial methods.
While EPA believes that non-human sources are capable of transmitting pathogens that can cause
the specific kinds of gastrointestinal illness identified in EPA's original epidemiological studies, the
specific risk from these sources has not been fully determined. The risk presented by fecal
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contamination of waters by non-human sources is possibly less significant; however, the increasing I
number of cases described above in which animals are the likely cause of the contamination and |
resulting illness present a compelling case to protect waters where human contact or consumption
are likely to occur. In addition, because the presence of bacterial indicators may provide evidence
of fecal pollution, high levels of these indicator organisms originating from animal sources may also
indicate the presence of pathogens capable of causing other human illnesses in addition to acute
gastroenteritis. |
A study conducted by Calderon et al. (1991) sought to determine if the human health risk
from animal sources could be quantified. The study was conducted on a small, three-acre pond in
a semi-rural community in central Connecticut and examined the relationship between water quality
degraded by dispersed, unidentified sources of animal fecal contamination and swimmer illness. It
found that although large numbers of indicator organisms were contributed to the waterbody by
animals, the resulting health risk was statistically insignificant at the 95% confidence interval to
swimmers. This study concluded that EPA's currently recommended bacterial indicators are
ineffective for predicting potential health effects associated with water contaminated by animal
sources of fecal pollution.
*
Because of the relatively small sample size and the closeness of the statistical analyses to
demonstrating that a relationship existed between enterococci concentrations and swimmer illness,
EPA believes that this single study does not provide an adequate basis to conclude that non-human
sources of fecal contamination have no potential to cause gastrointestinal illness in humans. (That
is, the study p-value was 0.059 when analyzing the correlation between enterococci and swimmer
illness. A p-value less than 0.05 would have indicated a strong relationship between the two
parameters.)
Unless and until the time that the absence of a relationship between non-human sources of
fecal contamination and human illness rates is established, EPA recommends that states and
authorized tribes apply their water quality criteria for bacteria to all waterbodies designated with
primary contact recreation in order to ensure protection of human health from gastrointestinal illness,
and thus is changing its policy regarding non-human sources of fecal contamination from what was
previously contained in the 1994 Water Quality Standards Handbook on this issue.
While EPA believes a change in this policy is necessary to ensure protection of human health,
EPA acknowledges such a change may present states and authorized tribes with difficulties, such as
the routine exceedance of the ambient water quality criterion due to natural sources of pollution.
Changes to the designated use may be the most appropriate way to address these situations.
Examples of natural (and potentially uncontrollable) sources are resident wildlife populations,
migrating waterfowl, wildlife refuges, or lakes frequented by waterfowl. For waterbodies affected
by natural sources such as these, where a significant portion of fecal contamination is shown to be
from natural sources and a state or authorized tribe demonstrates the water quality criterion for
bacteria and the primary contact recreation designated use is not attainable through the control of
other sources, an intermittent, wildlife impacted, or secondary contact recreational use may be the
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most appropriate designated use. Section 4.4.2 discusses the process a state or authorized tribe
would follow to refine recreational uses where contamination from natural sources is significant.
4.3 What is EPA's policy regarding high levels of indicator organisms originating from
environmental sources in tropical climates?
Recent research has raised the possibility that EPA's recommended indicator bacteria, E. coli
and enterococci, may not be appropriate indicators for assessing the risk of gastrointestinal illness
in tropical recreational waters. E. coli and enterococci have been found to persist in soils and
waterbodies (Fujioka et al., 1999; Fujioka and Byappanahalli, 1998; Lopez-Torres et-al., 1987).
Some researchers have hypothesized that these bacteria have developed mechanisms to maintain
viable cell populations for significant periods of time under uniform tropical conditions (Fujioka,
1998). Because of these observations, some states and authorized tribes have expressed a concern
that the use of EPA's recommended indicator organisms will result high observed concentrations
of these bacteria that are not indicative of human health risks.
4.3.1 Does EPA recommend a different indicator for tropical climates?
At this time, EPA does not recommend that states and authorized tribes use different bacteria
indicators for recreational waters in tropical climates. EPA's continued recommendation to apply
E. coli and/or enterococci criteria for the protection of recreational waters in tropical climates is
based on an expert workshop held recently on this issue and the scientific information available to
date. mMarch2001, an EPA-funded workshop was held in Hawaii to evaluate the existing scientific
body of information on the adequacy of current indicators for tropical waters. International experts
who either have conducted studies or who were otherwise very familiar with the scientific data base
regarding E. coli or enterococci indicator persistence and growth in tropical environments were
tasked to determine if these indicators remained appropriate for determining water quality and
associated exposure risks for gastrointestinal disease in recreational waters. While the final report
from this expert workshop has not yet been completed, EPA's preliminary assessment of the
workshop's outcome is that the evidence is not compelling to change its recommendation for states
and authorized tribes to use E. coli or enterococci criteria to ensure protection of .their tropical
"recreational waters. The Agency believes there currently are insufficient data and information
concerning possible adverse health implications to support a recommendation for the use of different
tropical indicators. EPA will consider further research to determine whether or not environmental
mechanisms favoring the persistence or growth of E. coli and enterococci indicators impact upon
correctly determining the safety of tropical recreational waters. Also, EPA will review the tropical
indicators workshop report, when completed, to determine research and policy needs and to pursue
future research on alternative indicators that may be better suited for characterizing tropical
recreational water quality.
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4.3.2 What options are available to states and authorized tribes to address the
applicability of EPA's recommended water quality criteria for bacteria in
tropical climates?
States and authorized tribes have several options to modify their water quality standards
and/or implementation procedures to address the potential for bacterial indicators to persist in
tropical climates. First, a state or authorized tribe may develop water quality criteria applicable to
recreational waters in tropical climate using alternative indicators. If a state or authorized tribe
wishes to pursue this approach, they should apply a risk-based methodology to the development of
the water quality criteria to establish a correlation between alternative indicator organism
concentrations and gastrointestinal illness. This approach would be consistent with EPA's
requirements for the development of scientifically defensible criteria. See 40 C.F.R..
§131.11(b)(l)(iii). Li addition to demonstrating a statistically significant relationship to
gastrointestinal illness, an alternative indicator should be indicative of recent contamination and be
detectable and quantifiable using acceptable peer-reviewed analytical methods.
Clostridium perfringens has been identified as a candidate organism having potential as a
bacteriological tracer of fecal pollution. However, studies have yet to be conducted demonstrating
a correlation between C. perfringens and the incidence of gastrointestinal illness. In addition,
because C. perfringens forms spores that can survive for extended periods of time, EPA continues
to have concerns regarding the ability of C. perfringens to indicate recent fecal contamination.
However, for states and authorized tribes that do not wish to undertake resource-intensive
epidemiological studies, C. perfringens, or another microorganism associated with fecal pollution
maybe adopted as an additional tracer of fecal pollution. EPA recommends the use of enterococci
(expressed both as a geometric mean and single sample maximum) as the primary bacteriological
indicator for marine and fresh waters (or E. coli for fresh waters), with a secondary tracer of human
fecal contamination if desired. For a state or authorized tribe with tropical waters that chooses this
approach, the use of the criteria and an additional tracer of fecal contamination in conjunction with
site surveys should be adequate to protect the primary contact recreational uses. EPA will work with
states and authorized tribes concerned about the applicability of EPA's recommended criteria in
tropical waters on developing appropriate implementation procedures that take into account the
behavior of indicator organisms in tropical climates.
Another option is the adoption of a subcategory of recreation use with appropriate criteria
reflecting these natural conditions similar to the process described in section 4.4.2 for waterbodies
impacted by high levels of wildlife fecal pollution. An approach such as this would be appropriate
if it can be shown that the primary contact recreation is not an existing use, the source of pollution
is not from anthropogenic sources, and that the primary contact designated use cannot be attained
due to naturally-occurringpollutant concentrations preventing the attainment of the use. (See section
4.4.2 for additional details.)
EPA notes that states and authorized tribes should exercise caution in undertaking this latter
approach; domestic pets and wildlife (especially waterfowl) can contribute significant numbers of
indicator bacteria. While such non-human sources may be less significant in the transmission of the
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types of gastrointestinal illnesses identified in EPA's original epidemiological studies, the bacterial
indicators may indicate risks of other illnesses. Recent outbreaks of enterohemorrhagic E. coli
O157:H7, Giardia, and Cryptosporidium, which are frequently of animal origin, may cause
significant illness. (See section 4.2 for information on human health risks from animal sources of
fecal contamination.)
In addition to the approaches described here, other approaches may also be appropriate. EPA
will work with states and authorized tribes interested in developing such approaches to assure they
meet the requirements of the Clean Water Act and federal regulations. In general, the above
approaches are applicable to any tropical area with high background concentrations of indicator
bacteria. However, prior to any change to water quality standards or implementation procedures,
EPA strongly recommends conducting sanitary surveys in addition to bacteria indicator monitoring,
especially hi areas where higher than normal bacteria densities are observed during monitoring. A
discussion of sanitary surveys and additional related resources is provided at the beginning of section
4. •
4.4 What options exist for adopting subcategories of recreation uses?
States and authorized tribes may adopt subcategories of recreation uses. More choices in
subcategories of recreational uses will allow states and authorized tribes to better tailor the level of
protection to the waterbody where it is most needed, while maintaining some protection for
unanticipated recreation in waters where primary contact recreation is unattainable. Examples of
such categories are primary contact recreation uses modified to reflect high flow situations or
waterbodies significantly impacted by wildlife sources of fecal contamination. In determining the
appropriate recreational use for a waterbody, states and authorized tribes should consider the fact that
in certain circumstances people will use whatever waterbodies are available for recreation, regardless
of the physical conditions, and that adopting a recreational use subcategory may necessitate a
concurrent plan or actions by the state or authorized tribe to communicate to the public the potential
risks or hazards associated with recreating in certain waterbodies.
In adopting recreational subcategories with criteria less stringent than that associated with
primary contact recreation, some analysis will be required. • While most recreational waters are
designated for primary contact recreation to protect people engaged in water immersion activities,
there are some waters where, if it can be shown that recreation is not an existing use pursuant to 40
CFR 131.10(h)(l), recreation uses may be removed altogether.6 States and authorized tribes must
justify a change to the primary contact recreation use for a waterbody through a use attainability
analysis. See 40 CFR 131.10(g). The level of analysis required will vary depending upon the type
of recreation use being designated. Table 4.1 provides a summary of EPA's recommendations and
the types of analyses that should accompany any state or tribal revision to its recreational uses.
6 40 CFR 131.3(e) defines existing uses as "those uses actually attained in the waterbody on or after
November 28, 1975, whether or not they are included in the water quality standards."
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These uses can include the designation of intermittent, secondary, or seasonal recreation uses.
Subject to the provisions of 40 CFR 131.10, recreation uses other than primary contact recreation
may be applicable to waters where, for example, human caused conditions combined with wet
weather events cannot be remedied, or where meeting the primary contact recreation use at all times
would result in substantial and widespread social and economic impact. Where states and authorized
tribes have adopted uses less than primary contact recreation, federal regulations require a re-
examination every three years to determine if any new information has become available to support
the designation of a more protective recreation use. See 40 CFR 131.20.
4.4.1 When is it appropriate to modify primary contact recreation uses to reflect high
flow situations?
An intermittent recreation use may be appropriate when the water quality criteria associated
with primary contact recreation are not attainable for all wet weather events. Meeting the water
quality criteria associated with the primary contact recreation use may be suspended during defined
periods of time, usually after a specified hydrologic or climatic event. EPA intends this intermittent
primary contact recreation use to be adopted for waterbodies in a limited number of circumstances,
contingent upon a state or authorized tribe demonstrating that the primary contact recreation use is
not an existing use, is not attainable through effluent limitations under CWA §301(b)(l)(A) and (B)
and §306 or through cost effective and reasonable best management practices, and meets one of the
six reasons listed under 40 CFR 131.10(g).7 The length of time the water quality criteria (and, thus,
the recreation uses) should be suspended during these events should be determined on a waterbody-
by-waterbody basis, taking into account the proximity of outfalls to sensitive areas, the amount of
rainfall, time of year, etc., and should not allow for any lowering of existing water quality.
EPA anticipates that the use of high flow cutoffs will be primarily applicable to flowing
waterbodies and still waters impacted by flowing waterbodies, where high flows are accompanied
by high levels of indicator bacteria that can not be controlled without substantial and widespread
7 One of the six conditions listed under 40 CFR 131.10(g) must be met in order to remove a designated use
which is not an existing use, or to establish sub-categories of a use:
(1) Naturally occurring pollutant concentrations prevent the attainment of the use; or
(2) Natural, ephemeral, intermittent or low flow conditions or water levels prevent the atttainment of the
use, unless these conditions may be compensated for by the discharge of sufficient volume of effluent discharges
without violating State water conservation requirements to enable uses to be met; or
(3) Human caused conditions or sources of pollution prevent the attainment of the use and cannot be
remedied or would cause more environmental damage to correct than to leave in place; or
(4) Dams, diversions or other types of hydrologic modifications preclude the attainment of the use, and it is
not feasibile to restore the waterbody to its original condition or to operate such modification in a way that would
result in the attainment of the use; or
(5) Physical conditions related to the natural features of the waterbody, such as the lack of a proper
substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality, preclude attainment of aquatic
life protection uses; or
(6) Controls more stringent than those required by sections 301(b) and 306 of the Act would result in
substantial and widespread economic and social impact.
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social and economic impact. When considering whether a high flow cutoff may be appropriate for
a particular waterbody, states and authorized tribes should evaluate the effects of the wet weather
events on the recreation use. For example, in some waterbodies, high flows routinely provide an
attractive recreation environment (e.g., for kayakers), making such waters ineligible for a high flow
cutoff because this type use of a waterbody constitutes an existing use which cannot be removed.
See 40 CFR 131.10(h)(l). In other circumstances, high wet weather flows result in dangerous
conditions physically precluding recreation (e.g., arroyo washes in the arid west), thus indicating that
primary contact recreation is not or should not be occurring. Waterbody flow and velocity vary
greatly among waterbodies depending on a combination of many factors, such as the amount of
impervious surface, slope, soil texture, vegetative cover, soil compaction, and soil moisture. The
conditions affecting velocity also vary with the depth and width of the waterbody's channel. These
variables affect the relationship between wet weather events and the resulting levels of indicator
bacteria.
Adoption of a high flow cutoff should be based on rigorous scientific assessment and needs
to reflect public input. If the waterbody is impacted by, combined sewer overflows, the supporting
analysis for any water quality standards revision should be consistent with, or reflected in, the Long
Term Control Plan (LTCP). Additionally, such a cutoff should apply on a case-by-case basis (rather
than state-wide, for example), should be tailored to the waterbody (rivers, as distinct from lakes), and
should set the cutoff at a point where it only applies under certain limited conditions. For flowing
waters, one approach is to specify the flow conditions when an exceedance may be allowed.
Alternately, for either flowing or still waters, a state or authorized tribe may specify a certain number
of events per year where the bacteriological criteria may be exceeded.
If a state or authorized tribe adopts a high flow cutoff, it should address several questions:
• Will other uses of the waterbody continue to be protected even when the high
flow cutoff is triggered?
• What is the resulting velocity during the high flow events when the
designated use would not be protected?
• Would the velocity during these events preclude all recreational uses
(including kayaking) that typically occur during high velocity flows?
. • Do the high flows have a minimal effect on the velocity of the flow, posing
little or no danger to persons using the waters for recreation?
• For how many days would the cutoff apply and how was the length of time
determined?
• Will the state or authorized tribe adopt the cutoff as a discharger-specific
variance, or create recreational subcategories that correlate to the cutoff?
• Has a use attainability analysis shown that additional controls within the
water watershed would result in substantial and widespread social and
economic impact?
• What effect would the high flow cutoff have on implementing controls for all
sources of bacterial contamination to the waterbody (e.g., CSOs, storm water,
leaking septic systems, feed lots, row crops, etc.)? .
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States and authorized tribes implementing such a high flow cutoff should include
scientifically valid methodologies for maintaining and protecting the primary contact recreational
uses when normal flow returns and for protecting downstream uses. While EPA has not developed
a national policy on a high flow/velocity cutoff for bacteria and recreational uses similar to its
4B3/7Q10 low flow recommendations for aquatic life criteria (e.g., the flow that results in a four-day
exceedance of a chronic aquatic life criterion once every three years, which is approximately equal
to the 7Q10, the lowest seven day flow that is likely to occur once every ten years), EPA envisions
a methodology that states and authorized tribes could apply on a site-specific basis using the
waterbody channel and landscape characteristics. States and authorized tribes could also create a
subcategory of the recreational uses to which the cutoff would apply. Since use of a high
flow/velocity cutoff reduces the level of protection for the waterbody, a use attainability analysis
would be required for each waterbody to which the high flow/velocity cutoff applies. It would be
particularly important to demonstrate that a community could not afford a higher level of control (or,
for example, additional storm water or agricultural best management practices) without substantial
and widespread social and economic impact. As with other changes in designated uses, the public
must have an opportunity to comment on the proposed revision to the water quality standard before
a state or authorized tribe adopts and submits it to EPA for approval or disapproval under CWA
§303(c).
For states and authorized tribes using this approach, EPA encourages the development of a
plan to communicate to the public the conditions under which recreation should not occur. For
waterbodies that are known to be beaches or heavily used recreation areas, EPA encourages caution
in adopting intermittent suspensions of the primary contact recreation use. If the state or authorized
tribe finds after public comment that such a revision to water quality standards for a beach area is
supported, EPA encourages beach managers to issue advisories during the cutoff conditions unless
monitoring data are collected indicating it is safe to recreate. EPA feels this is the most appropriate
implementation measure for those waters heavily used for recreation since the adoption of such a
cutoff presumes that, under the conditions specified by the state or authorized tribe, the bacterio-
logical criteria will be exceeded and, thus, may present a hazard to swimmers.
Further guidance on refining water quality standards specifically for combined sewer
overflow receiving waterbodies is contained in the Coordinating CSO Long-Term Planning With
Water Quality Standards Reviews (USEPA, 2001).
4.4.2 When is it be appropriate to adopt wildlife impacted recreation uses?
States and authorized tribes may refine designated uses if it can be demonstrated that primary
contact recreation is not an existing use and natural sources preclude the attainment of water quality
standards. Prior to exercising this option, a state or authorized tribe should gather data to address
the following questions:
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Is the waterbody publicly identified, advertised, or otherwise regularly
used or known by the public as a beach or swimming area where
primary contact recreation activities are encouraged to occur?
What is the existing water quality? If it is not currently meeting the
applicable recreational water quality standards, do the exceedances
occur on a seasonal basis, in response to rainfall events, or at other
times due to other conditions or weather-related events?
• Is the primary contact recreation use attainable through the appli-
cation of effluent limitations under CWA §301(b)(l)(A) and (B) and
§306 or through cost effective and reasonable best management
practices?
What are the sources of fecal pollution within the waterbody? What
are the relative contributions of these sources?
The first two questions will assist the state or authorized tribe in determining whether or not
primary contact recreation is an existing use. In answering these questions, both water quality and
the actual use that has occurred since November 28, 1975 should be considered. See 40 CFR
131.3(e). Information provided by the public should be considered by the state or authorized tribe
in making this determination. The state or authorized tribe should provide documentation of the
waterbody's historical water quality, if available, and the use of the waterbody for recreation in
support of its conclusion that primary contact recreation is not an existing use.
Secondly, the state or authorized tribe should determine that natural sources, and not leaking
septic tanks or other anthropogenic sources, prevent attainment of water quality standards. To
ascertain whether natural sources are the cause of impairment, several tools are available. Sanitary
surveys may be conducted to identify the sources contributing to a waterbody. Recommendations
on conducting sanitary surveys and additional references are contained at the beginning of section
4. Detection of detergents, dyes, or caffeine may indicate human sewage as the source of fecal
pollution. Knowledge of land use patterns within a watershed may also assist states and authorized
tribes in determining the relative contribution sources of fecal contamination within a watershed.
In addition, other analytical tools are becoming more common in identifying the sources of fecal
contamination. While Bacterial Source Tracking methods such as ribotyping and Antibiotic
Resistance Analysis are becoming more common, such methods may be cost prohibitive for many
states and authorized tribes to use on a large scale (See, for example, Dombeck et al., 2000; Harwood
et al., 2000, Wiggins et al., 1999).
The results of the sanitary survey or other methods demonstrating that natural sources
preclude attainment of primary contact recreation should be sufficient to conclude that primary
contact recreation is not attainable under 40 CFR 131.10(g)(l), on the grounds that naturally-
occurring pollutant concentrations prevent the attainment of the use. When removing a CWA
§101(a) goal use or adopting subcategories of those uses, under 40 CFR 131.10(g), states and
authorized tribes are required to submit an analysis demonstrating that the use is not an existing use
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and justifying the removal of that use based on one of the six reasons listed in that section. When
contemplating revisions to water quality standards based upon impacts from natural sources, EPA
encourages states and authorized tribes to use scientifically defensible methods in their supporting
analyses. EPA will review this information as part of its review and action on any revised water
quality standards. EPA believes answering the questions identified above should assist the state or
authorized tribe in making a scientifically defensible determination that natural sources preclude
attainment of the primary contact recreation use.
Once the initial analysis has been completed, states and authorized tribes have several options
for revising their recreational water quality standards. A state or authorized tribe could pursue
adoption of a wildlife impacted recreation use as a recreational use subcategory, or, for waterbodies
where water quality sufficient to support primary contact recreation is unattainable and location or
barriers make recreation unlikely to occur, consider the adoption of a secondary contact recreation
use or removal of recreation uses. Establishing a wildlife impacted recreation use would be
appropriate for waters where limited recreational activities may still occur. EPA recommends that
states and authorized tribes wishing to adopt a wildlife impacted recreation use adopt a criterion
reflecting the natural levels of bacteria and, because the specific risk to people recreating in these
waters is unknown, develop a plan to communicate to the public the potential risk of recreating in
waters designated with this use. This communication could include public announcements or sign
posting along the waterbody. Ideally, the state or authorized tribe should have monitoring and/or
modeling data that would assist in identifying the natural levels of indicator organisms. Because
such contributions are often correlated with rainfall events, the state or authorized tribe should
consider the level of bacterial indicators present during dry and wet weather as well as any other
spatial or temporal variability to assist in the establishment of an appropriate criterion. EPA
envisions that a wildlife impacted recreation use category would provide greater protection than a
secondary contact recreation use. However, wildlife sources of fecal contamination may still present
some additional risk to recreators. Therefore, if the state or authorized tribe is adopting a less
stringent criterion, the increment of change should correspond only to the estimated amount of the
bacteria that is present due to natural sources.
Where it is shown that primary contact recreation is not an existing use and that the
waterbody is significantly impacted by wildlife contamination, states and authorized tribes may
adopt a secondary contact recreation use or remove the recreational use altogether. In determining
whether recreation is an existing use, states and authorized tribes should consider the location of the
waterbody and any barriers that may exist that would preclude the use of the waterbody for primary
contact recreation. See section 4.5 for a discussion of secondary contact recreation uses and criteria.
Other water quality standards approaches beyond those described here may also be
appropriate. EPA will work with states and authorized tribes interested in developing such
approaches to assure they meet the requirements of the Clean Water Act and federal regulations.
Regardless of the option a state or authorized tribe pursues, EPA emphasizes the importance of
public participation in revising its water quality standards. -
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Use of this approach can provide states and authorized tribes with the means to acknowledge
the type of fecal pollution that exists and its potential risk to recreators. Concern has been expressed
that the use of this approach may provide existing NPDES permitted dischargers with relaxed
effluent limitations. In the case where a discharger has a water quality based effluent limitation
(WQBEL) for bacteriological criteria, it would not be eligible for less stringent effluent limitations
unless an antidegradation analysis was performed consistent with the federal and state (or tribal)
regulations. See 40 CFR 131.12. In addition, an analysis should be performed as part of the
development of the WQBEL that considers the receiving waterbody' s water quality and to determine
whether of the discharge has the resonable potential to cause or contribute to the exceedance of
applicable water quality standards. See 40 CFR 122.44(d).
4.5 What is EPA's policy regarding secondary contact recreation uses?
While recreational waters have been designated by states and authorized tribes for primary
contact recreation to protect people engaged in recreational activities, there are some waters where
a secondary contact recreation use with less stringent water quality criterion may be more
appropriate. Activities that constitute secondary contact recreation include those in which contact
and immersion with the water is unlikely. States and authorized tribes may justify the adoption of
a secondary contact recreation use through a use attainability analysis. See 40 CFR 131.10(g).
Subject to the provisions of 40 CFR 131.10, a secondary contact recreation use may be applicable
to waters that are, for example, impacted by human caused conditions that cannot be remedied, or
where meeting the criteria associated with the primary contact recreation use would result in
substantial and widespread social and economic impact.
4.5.1. When is it appropriate to designate a secondary recreation use?
EPA considers waters designated for primary contact recreation and waters designated for
secondary contact recreation with bacteriological water quality criteria sufficient to support primary
contact recreation to be consistent with the CWA §101(a) goal uses. States and authorized tribes
may designate other recreation uses after demonstrating that primary contact recreation is not an
existing use and the water quality necessary to support the use is not attainable based on chemical,
physical, and biological analyses, as well as economic considerations. See 40 CFR 131.10(g). Any
adoption of a secondary contact recreation use with less stringent water quality criteria than required
for primary contact recreation or the removal of recreation uses requires the state or authorized tribe
to submit appropriate justification for the change in designated use to EPA for review and approval.
See 40 CFR 131.100')- Also, see section 4.5.3 for EPA's recommended water quality criteria for
secondary contact recreation uses.
• Where a primary contact recreation use and the water quality necessary to support the use is
not attainable and primary contact recreation is not an existing use, the state or authorized tribe
should evaluate whether the other subcategories of recreation described in the previous sections are
appropriate. If not, a secondary contact recreation use with less stringent water quality criteria may
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be appropriate. An example would be a situation where flowing or pooled water is not present
within a waterbody during the months when primary contact recreation would otherwise take place
and the waterbody is not in close proximity to residential areas, thereby indicating that primary
contact recreation is not likely to be an existing use. If it can also be demonstrated that natural,
ephemeral, intermittent, or low flow conditions or water levels prevent attainment of the primary
contact recreation use, a secondary contact recreation use may be appropriate. Another example
would be a discharger that may not be able to meet limits necessary to protect the primary contact
recreation use without causing substantial and widespread social and economic impact, but can meet
limits that would assure protection of a secondary contact recreation use. These demonstrations
would fulfill the requirements of and address one of the six conditions contained in 40 CFR
131.10(g) justifying the removal of a designated use. In addition, as discussed in section 4.4.2,
designating a secondary contact recreation use may also be appropriate where primary contact
recreation is not an existing use and high levels of natural and uncontrollable fecal pollution exist.
4.5.2 What information should be contained in a use attainability analysis to remove
a primary contact recreation use?
States and authorized tribes should consult EPA guidance (USEPA, 1995; USEPA, 1994)
for general guidelines on conducting use attainability analyses for recreation uses. The likely
components of a use attainability analysis for recreation uses may include:
• physical analyses considering the actual use, public access to the waterbody,
facilities promoting the use of recreation, proximity to residential areas,
safety considerations, and substrate, depth, width, etc. of a waterbody;
• chemical analyses of existing water quality;
• potential for water qualityimprovements including an assessment of nutrients
and bacteriological contaminants; and
• economic/affordability analyses.
(See also sections 4.4.1 for changes to recreation uses for waterbodies impacted by
bacteria associated with high flow conditions and 4.4.2 for waterbodies impacted by
non-human sources.)
On the subject of physical analyses, EPA has previously stated that, "Physical factors, which
are important in determining attainability of aquatic life uses, may riot be used as the basis for not
designating a recreational use consistent with the CWA section 101(a)(2) goal" (USEPA, 1994).
EPA continues to believe that physical factors alone would not be sufficient justification for
removing or failing to designate a primary contact recreation use. EPA's suggested approach to the
recreational use issue is for states and authorized tribes to look at a suite of factors such as whether
the waterbody is actually being used for primary contact recreation, existing water quality, water
quality potential, access, recreational facilities, location, safety considerations, and physical
conditions of the waterbody in making any use attainability decision. Any one of these factors,
alone, may not be sufficient tb conclude that designation of the use is not warranted.
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EPA continues to believe that downgrading or removing recreational uses due only to
physical conditions is inappropriate when it is otherwise feasible to meet water quality standards.
However, when considered with other data collected for a use attainability analysis, there are a few
instances where physical considerations may play an important role in informing a state or authorized
tribe's decision to refine a recreation use and, in particular, in determining whether or not primary
contact recreation is an existing use. This may include a waterbody where access is prevented by
•fencing or in an urban waterbody that also serves as a shipping port or has close proximity to
shipping lanes. It may also include waterbodies where primary contact recreation is not an existing
use, it can be demonstrated that flowing or pooled water is not present during the months when
recreation would otherwise take place, and that the waterbody is not in close proximity to residential
areas. In instances such as these, the physical attributes help to ensure primary recreation does not
and will not occur in these waterbodies.
EPA understands that substantial and widespread social and economic impacts are often
determining factors in assessing whether or not the primary contact recreation use and water quality
to support the use can be met. EPA has published guidance to assist states and authorized tribes in
considering economic impacts when adopting water quality standards (USEPA, 1995). The cost of
placing additional control measures on sources of fecal contamination are often cited as the reason
a water cannot attain the primary contact recreation use and the associated water quality criteria in
all waters at all times, hi the use attainability analysis process, the federal regulation at 40 CFR
131.10(g) lists the factors that may be used to demonstrate that a primary contact recreation use
cannot be met; these factors include substantial and widespread social and economic impact, and
natural conditions. EPA reminds the reader that water quality criteria are derived to address the
effects of pollution concentrations on the environment and human health. As such, water quality
criteria do not reflect consideration of economic impacts or the technological feasibility of meeting
the ambient criterion concentration in the waterbodies, while under the federal regulation, the setting
of designated uses (and the associated protective criteria) may take into account social and economic
considerations. See 40 CFR 131.10(g).
4.5.3 What water quality criteria should be applied to waters designated for
secondary contact recreation?
For waterbodies where a state or authorized tribe demonstrates through a use attainability
analysis that removing a primary contact recreation use is justified, adoption of a recreation use and
water quality criteria to protect secondary contact activities may be appropriate. EPA defines
secondary contact activities as those activities where most participants would have very little direct
contact with the water and where ingestion of water is unlikely. Secondary contact activities may
include wading, canoeing, motor boating, fishing., etc. Many states and authorized tribes have
adopted secondary contact recreation uses for waterbodies. States and authorized tribes with
bacteriological water quality criteria based on fecal coliforms have generally adopted a secondary
contact water quality criterion of 1000 cfu/100ml geometric mean, which is five times the geometric
mean value used by many states and authorized tribes to protect primary contact recreation. This
water quality criterion has been applied to secondary contact uses and to seasonal recreation uses
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during the months of the year not associated with primary recreation. The Ambient Water Quality
Criteria for Bacteria-1986 recommending E. coli and enterococci as indicators did not recommend
water quality criteria for recreation uses other than primary contact recreation. States and authorized
tribes have cited this as one reason why they have not adopted EPA's recommended water quality
criteria.
During the development of this guidance document, EPA explored the feasibility of
scientifically deriving criteria for secondary contact waters and found it infeasible for several"
reasons. In reviewing the data generated in the epidemiological studies conducted by EPA that |
formed the basis for its 1986 criteria recommendations, EPA found that these data would be'
unsuitable for the development of a secondary contact criterion. The exposure data collected were
associated with swimming-related activities involving immersion. Secondary contact recreation
activities generally do not involve immersion in the water, unless it is incidental (e.g., slipping and
falling into the water or water being inadvertently splashed in the face). While the main illness likely
to be contracted during primary contact recreation is gastrointestinal illness, illnesses contracted from
secondary contact recreation activities mayjust as likely be diseases and conditions affecting the eye,
ear, skin, and upper respiratory tract. Because of the different exposure scenarios and the different
exposure routes that are likely to occur under the two different types of uses, EPA is unable to derive
a national criterion for secondary contact recreation based upon existing data.
Despite the lack of information necessary to develop a risk-based secondary contact
recreation criterion, EPA believes that waters designated for secondary contact recreation should also
have in place an accompanying numeric criterion. Protecting waters designated for secondary
contact recreation with a numeric criterion for bacteria provides the basis for the development of
effluent limitations and, where applicable, the implementation of best management practices. Such
an approach also provides a mechanism to assure that downstream uses are protected and, where
adopted as part of a seasonal recreation use, help to assure that the primary contact recreation use
is not precluded during the recreation season. Adoption of a numeric criterion is a straightforward
approach, transparent to the public, and consistent with historical practices. In pursuing this
approach, states and authorized tribes may wish to adopt a criterion five times that of the geometric
mean component of the criterion adopted to protect primary contact recreation, similar to the
approach states and authorized tribes have used historically in the adoption a secondary contact
criterion for fecal coliforms. In evaluating attainment with this criterion, states and authorized tribes
may wish to calculate geometric mean values based on samples taken over a 30 day period or on a
seasonal or annual basis. Another approach would be the adoption of numeric criterion as a
maximum value protective of the secondary contact recreation use. EPA feels that this would also
be an appropriate approach, particularly for states and authorized tribes that are unable to collect
sufficient monitoring data to calculate a geometric mean value. A narrative criterion along with
implementation procedures may also form the basis for these measures. States and authorized tribes
may also pursue an alternate approach to the protection of secondary contact recreation waters, and
EPA will work with the state or authorized tribe to ensure the approach is protective of the
designated use and meets the above objectives.
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4.5.4 Will EPA publish risk-based water quality criteria to protect for "secondary
contact" uses?
EPA's Ambient Water Quality Criteria for Bacteria-1986 are designed to protect the public
from gastrointestinal illnesses associated with accidental ingestion of water. EPA has not developed
any water quality criteria for secondary contact recreation to protect for other human health-based
risks. Such additional water quality criteria could conceivably be based on the effects of dermal
contact, such as rashes or other minor skin irritations or infections, and inhalation of water. As part
of EPA's requirements under the BEACH Act amendments and commitments made in its Beach
Action Plan, EPA intends to gather additional data and investigate the development of water quality
criteria for transmission of organisms that cause skin, eye, ear, nose, respiratory illness, or throat
infections. Some elements of such future water quality criteria may potentially be applicable to
secondary contact uses.
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Table 4.1 Recreation Uses, Criteria, and Supporting Analyses
Designated Use
Criterion
Primary Contact Recreation
Identified/Popular Beach
Areas
Other Primary Contact
Recreation Waters
Seasonal Recreation Use
Criteria based on risk levels of 8 or
fewer illnesses/1000 swimmers
(fresh waters) and 19 or fewer
illnesses/1000 swimmers (marine
waters).
Criteria based on risk level not
greater than 14 illnesses/1000
swimmers (fresh waters) and not
greater than 19 illness/1000 swim-
mers (marine waters).
Primary contact recreation criteria
apply during specified recreational
season; secondary contact rec-
reation criteria apply rest of year.
Supporting Analysis
None.
None.
Information explaining choice of rec-
reation season (e.g., water & air tem-
peratures, time of use, etc.).
Recreational Use Subcategories
Exceptions for High Flow
Events
Wildlife Impacted Recreation
Exception to criteria at high flows
on a waterbody-by-waterbody basis
based on flow statistic or number of
exceedances allowed.
Criteria to reflect the natural levels
of bacteria while providing greater
protection than criteria adopted to
protect a secondary contact rec-
reation use.
Use Attainability Analysis consistent
with 40 CFR 131.10(g); demon-
stration that primary contact rec-
reation is not an existing use.
Use Attainability Analysis consistent
with 40 CFR 13 1. 10(g) and data dem-
onstrating wildlife contributes a sig-
nificant portion of fecal contamin-
ation; demonstration that primary con-
tact recreation is not an existing use.
Other Categories of Recreation
Secondary Contact
Recreation
Criteria sufficient to protect the use.
May use numeric criterion protec-
tive of secondary contact
recreation(suggest specifying cri-
terion expressed as maximum value
or criterion expressed as geometric
mean five times primary contact
recreation geometric mean value) or
narrative criterion.
Use Attainability Analysis consistent
with 40 CFR 131.10(g); demon-
stration that primary contact rec-
reation is not an existing use.
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Escherichia coli O157:H7 and Shigella sonnei. New Eng. J. Med. 331(9): 579-584.
Lopez-Torres, Arleen J., et al. 1987. Distribution and in situ survival and activity of Klebsiellh
pneumoniae andEscherichia coli in a tropical rain forest watershed. Current Microbiol. 15:213 -21 si
National Shellfish Sanitation Program (NSSP). 1999. National Shellfish Sanitation Program Model
Ordinance. National Shellfish Sanitation Program. US Food and Drug Administration, Washington!
DC.
Ontario's Ministry of the Attorney General. 2000. Part One, Report of the Walkerton Inquiry £. coll
Outbreak: The Events of May 2000 and Related Issues. Toronto, Ontario, Canada.
.USDA. 1993. National Animal Health Monitoring System (NAHMS) Report: Cryptosporidiui
parvum Outbreak, (on-line) URL: http://www.aphis.usda.gov/vs/ceah/cahm/Dairy_Cattle/
ndhep/dhpcryptxthtm.
USEPA. 2001. Guidance: Coordinating CSO Long-Term Planning With Water Quality Standards!
Reviews. U.S. Environmental Protection Agency, Office of Water, Washington DC EPA-833-R-I
01-002. •
USEPA. 1999. Guidance Manual for Conducting Sanitary Surveys of Public Water Systems;
Surface Water and Ground Water Under the Direct Influence (GWUDI) of Surface Water. U.S.
Environmental Protection Agency, Office of Water, Washington, D.C. EPA-815-R-99-016.
USEPA. 1995. Interim Economic Guidance for Water Quality Standards. U.S. Environmental
Protection Agency. EPA-823-B-95-002.
USEPA. 1994. WaterQualityStandardsHandbook:SecondEdition. U.S. Environmental Protection
Agency. EPA-823-B-94-005.
USEPA. 1984. Health Effects Criteria for Fresh Recreational Waters. U.S. Environmental Protection
Agency. EPA-600/1-84-004.
USEPA. 1983. Health Effects Criteria for Marine Recreational Waters. U.S. Environmental
Protection Agency. EPA-600/1 -80-031.
Wiggins, B.A., et al. 1999. Use of antibiotic resistance analysis to identify nonpoint sources of fecal
pollution. Appl. Environ. Microbiol. 65:3483-3486.
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5. Implementation of EPA's Ambient Water Quality Criteria for Bacteria -1986 in State
and Authorized Tribal Water Quality Programs
5.1 What is EPA's recommended approach for states and authorized tribes making the
transition from fecal coliforms to E. coli and/or enterococci?
EPA recognizes that states and authorized tribes that have yet to adopt EPA's recommended
1986 water quality criteria for bacteria may be concerned about how to ensure consistency and
continuity within their regulatory programs. Specifically, states and authorized tribes may have
concerns about making regulatory decisions during this transition period while an adequate
monitoring database is being established. To facilitate this period of transition, states and authorized
tribes may include both fecal coliforms and E. co/z'/enterococci in their water quality standards for
the protection of designated recreational waters for a limited period of time, generally one triennial
review cycle. The dual sets of applicable criteria will enable regulatory decisions and actions to
continue while collecting data for the newly adopted E. coli or enterococci criteria. For states and
authorized tribes choosing this approach, EPA expects that during this limited period of time, states
and authorized tribes will be actively collecting data on E. coli and/or enterococci and working to
incorporate E. coli and/or enterococci water quality criteria into their water quality programs, e.g.,
National Pollutant Discharge Elimination System (NPDES), 305(b), and 303(d) programs.
Alternatively, states and authorized tribes may elect to concurrently adopt a delayed effective date
to allow for time in which to collect data on the newly adopted criteria. With these options
available, lack of data should not delay states' and authorized tribes' adoption of E. coli and/or
enterococci. Once E. coli and/or enterococci are adopted into state or tribal water quality standards,
EPA encourages states and authorized tribes to remove the fecal coliform criterion as it applies to
recreational waters during its next triennial review, since retaining the fecal coliform criterion for
recreational waters may result in additional permitting and monitoring requirements.
Attainment of water quality criteria for bacteria is a critical component of ensuring assessing
the attainment of primary contact recreation uses. Once adopted as water quality standards by states,
authorized tribes, or EPA, these water quality criteria form the basis for water quality program
actions,.both regulatory and non-regulatory. For example, water quality criteria are used in
.establishing NPDES water quality-based effluent limitations (WQBELs), listing impaired waters
under section 303(d), and beach monitoring and advisory programs. How the adopted criteria will
be used in these different programs should be clearly explained in states' and authorized tribes' water
quality standards or supporting implementation documents.
EPA recommends that states and authorized tribes adopt water quality criteria for bacteria
containing both the geometric mean and single sample maximum components and use both
components when assessing and determining attainment of waters designated for primary contact
recreation. With regard to interpreting the geometric mean component of the criteria, there has been
a common misconception of how water quality data should be used to determine whether or not a
waterbody has attained the applicable geometric mean value. Some states and authorized tribes have
mistakenly interpreted the water quality criteria as requiring a minimum number of samples in order
to determine the attainment of the geometric mean component of the water quality criteria. The
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confusion may have arisen because the water quality criteria recommend a monitoring frequency of I
five samples taken over a 30-day period. The recommendation does not intend to imply that five f
samples are needed before a geometric mean can be calculated. The minimum number of samples
used in the 1986 water quality criteria for bacteria is for accuracy purposes only; clearly, more
frequent sampling yields more accurate results when determining the geometric mean. Further, in
some instances averaging periods greater than 30 days may be appropriate. Unless specified
otherwise in a state or authorized tribe's water quality standards or assessment methodology, the
geometric mean should be calculated based on the total number of samples collected over the
specified monitoring period in conjunction with a single sample maximum to determine attainment
of the numeric water quality criteria (e.g., CWA §303(d) listing for fresh and marine waters),
regardless of the number of samples collected. This interpretation encourages the collection and use
of data and is what has always been intended. EPA notes that this interpretation was used by the
Agency when promulgating water quality standards for the Colville Confederated Tribes (40 CFR
131.35).
5.2 How should states and authorized tribes implement water quality criteria for bacteria
in their NPDES permitting programs8?
States and authorized tribes have discretion in how NPDES water quality-based effluent
limits for bacteria are specified. The following sections describe how limits may be established by
the permitting authority for different discharge types and consistent with the applicable federal
requirements. Two scenarios are discussed: first, the period of time during which states and
authorized tribes are making the transition from fecal coliform criteria to E. coli or enterococci
criteria, and second, developing limits once theE. co/z'/enterococci criteria have been established in
state and tribal water quality standards.
5.2.1 While transitioning from fecal coliforms to E. coli and/or enterococci, how
should states and authorized tribes implement water quality criteria for
bacteria in their NPDES permitting programs?
If a state or authorized tribe chooses to retain its fecal coliform criterion during a transitional
period after adoption of E. coli and/or enterococci as water quality criteria, any new or reissued
permits would need to contain water quality-based effluent limits, as appropriate and unless specified
otherwise in a state or authorized tribe's water quality standards, reflecting both criteria to be
consistent with the federal requirement at 40 CFR 122.44(d)(l)(i). This provision requires water
quality-based permits containing limits for those pollutants (including all bacterial pollutants) the
permitting authority determines are or may be discharged at a level which will cause, have
Pursuant to section 518(e) of the CWA, EPA is authorized to treat an Indian tribe in the same manner as a
state for the purposes of administering a NPDES program. 40 CFR 123.31-121.34 establishes the procedures and
criteria by which the Agency makes such a determination. At this time, several tribes are in the process of requesting
program authorization;-however, to date no tribe has been granted authorization to administer an NPDES program.
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reasonable potential to cause, or contribute to an exc<§edance of any applicable water quality
standard. In this case, the existence of "reasonable potential" for fecal coliforms would also indicate
the existence of reasonable potential for any other criterion for bacteria adopted by the state or
authorized tribe. In most cases, wastewater treatment plants that have used secondary and tertiary
treatment for fecal coliforms should find that this treatment also adequately addresses E. coli and
enterococci (Miescier and Cabelli, 1982). However, wastewater treatment plants chlorinating their
effluent may find enterococci more resistant to chlorination than fecal coliforms or E. coli (Oregon
Association of Clean Water Agencies, 1993; Miescier and Cabelli, 1982).
5.2.2 Once E. coli and/or enterococci have been adopted by states and authorized
tribes, how should the water quality criteria for bacteria be implemented in
NPDES permits ?
Many states and authorized tribes have raised concerns regarding how state and tribal water
quality standards based on EPA's 1986 water quality criteria for bacteria should be implemented
through NPDES permits. Under the Clean Water Act and the implementing federal regulations,
states and authorized tribes have flexibility in how they translate water quality standards into NPDES
permit limits to ensure attainment of designated uses. In implementing state and tribal water quality
standards that include both the geometric mean and single sample maximum components, there are
multiple acceptable approaches. EPA recommends, but would not require, that states and authorized
tribes use only the geometric mean component for NPDES water quality-based effluent limits.
Alternatively, states and authorized tribes could use both the geometric mean and single sample
maximum in the development of NPDES water quality-based effluent limits; or the single sample
maximum value expressed as a daily average limit for NPDES water quality-based effluent limits.
The Agency is aware that states have taken different approaches in deriving WQBELs for bacteria
to ensure the ambient water quality criteria are met. For example, many states apply the ambient
water quality criteria for bacteria directly to the discharge with no allowance for in-stream mixing
(this is often referred to as "criteria end-of-pipe"). Alternatively, some states provide mixing zones
for bacteria and derive permit limits that account for in-stream dilution. EPA has also stated that for
certain types of regulated discharges (e.g., municipal separate storm sewer systems [MS4s] and
concentrated animal feeding operations [CAFOs]), the most appropriate permit requirements may
be non-numeric effluent limitations expressed in the form of best management practices (BMPs).
The underlying principle, however, is that which ever approach is selected, the permitting authority
must determine that permit limits and requirements derive from and comply with applicable water
quality standards. See 40 CFR 122.44(d)(l)(vii)(A).
In determining a discharger's compliance with any effluent limitation, the federal regulation
requires that monitoring for any pollutant should never occur less than once per year. Further,
monitoring requirements should be established case-by-case based on the nature of the effluent. See
40 CFR 122.44(i)(2). More frequent sampling may be appropriate if the discharge is in close
proximity to beach areas or known recreation areas.
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With respect to determining whether WQBELs for bacteria are needed for a specific
discharge, the Agency expects permitting authorities to use the same approach that applies to other
pollutants. Thus, the permitting authority must include a WQBEL in the NPDES permit for a
discharger if it determines that a pollutant (including all bacteria pollutants) is or may be discharged
at a level which will cause, have reasonable potential to cause, or contribute to an exceedance of any
state or tribal water quality standard. See 40 CFR 122.44(d)(l)(i). When a state or authorized tribe
adopts, and EPA approves, new water quality criteria for E. coli and/or enterococci, the permitting
authority (in most cases, the state) must immediately begin implementing these criteria through
limits incorporated into any new or reissued NPDES permit, unless the state or tribal water quality
standards authorize another approach. Additionally, if the state or authorized tribe chooses to retain
an existing water quality criterion for fecal coliforms, the permitting authority must continue to
implement this criterion in the form of a WQBEL as well, unless otherwise specified in the state or
tribal water quality standards. In some cases where a discharge is released into a waterbody
designated for both recreation and shellfishing, even after removal of the fecal coliform criterion for
recreation, the permit will likely continue to contain effluent limitations for both parameters since
the fecal coliform criterion will continue to apply to waters designated for shellfishing.
Following state or tribal adoption and EPA approval of water quality criteria for E. coli
and/or enterococci, the Agency does not believe that permitting authorities will typically need to
reopen existing permits prior to their expiration dates to incorporate WQBELs based on the newly-
adopted water quality criteria. Instead the Agency expects that existing WQBELs for fecal coliforms
will continue to be enforced through the existing permit's term, and that permitting authorities will
incorporate WQBELs based on newly adopted water quality criteria (as needed) at the time of permit
reissuance.
5.2.3 How do the antibacksliding requirements apply to NPDES permits with effluent
limits for bacteria?
Dischargers that previously had NPDES water quality-based effluent limits for fecal
coliforms, and subsequently have water quality-based effluent limits based on a state or authorized
tribe's newly adopted E. coli and/or enterococci criteria should also be aware of federal NPDES
"antibacksliding" provisions. The CWA and implementing NPDES federal regulations contain
specific restrictions on when an existing WQBEL may be removed or replaced with a less stringent
effluent limitation in areissued NPDES permit. See CWA section 402(o); 40 CFR 122.44(1). When
a state or authorized tribe replaces a fecal coliform criterion with water quality criteria for E. coli
and/or enterococci, that replacement will not generally result in less stringent effluent limits in the
permit (i.e., replacing a 200 cfu/100 ml fecal coliform criterion with an E. coli criterion of 126
cfu/100 ml or an enterococci criterion of 33 cfu/100 ml for freshwater or 35 cfu/100 ml enterococci
criterion for marine water). In other words, if all other factors are unchanged, EPA expects that the
WQBEL(s) based on the newly adopted water quality criteria for bacteria (for E. coli and/or
enterococci), while perhaps expressed in a different form, will not be less stringent than the previous
WQBEL (for fecal coliform) and that, therefore, the backsliding prohibitions in section 402 of the
CWA and its implementing regulations will not apply.
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If a state or authorized tribe chooses to adopt E. coli or enterococci water quality criteria
greater than, for fresh waters, an E. coli criterion of 126 cfu/100 ml or an enterococci criterion of 33
cfu/100 ml or, for marine waters, an enterococci criterion of 35 cfu/100 ml (generally occurring
through the adoption of a subcategory of primary contact recreation use, other recreational
subcategories, or secondary contact recreation use), the antibacksliding elements of the CWA and
federal regulations would apply. In these instances, the CWA and federal regulations would allow
for backsliding in some circumstances as described below. EPA has consistently interpreted section
402(o)(l) of the CWA to allow relaxation of WQBELs if the requirements of CWA section
303(d)(4) are met. (While CWA §402(o)(2) allows for backsliding to occur when new information
is present, revised water quality standards regulations do not constitute "new information" under this
provision.)
Section 303(d)(4) has two parts: paragraph (A) which applies to "non-attainment waters" and
paragraph (B) which applies to "attainment waters."
Non-attainment water-Section 303(d)(4)(A) allows the establishment of less
stringent WQBELs for waters identified under CWA §303(d)(l)(A) as not
meeting applicable water quality standards (i.e., a "nonattainment water"), if
two conditions are met. First, the existing WQBEL must be based on a total
maximum daily load (TMDL) or other wasteload allocation. Second,
relaxation of a WQBEL is only allowed if attainment of water quality
standards will be assured.
Attainment water-Section 303(d)(4)(B) applies to waters where the water
quality equals or exceeds levels necessary to protect the designated use, or to
otherwise meet applicable water quality standards (i.e., an "attainment water").
Under section 303(d)(4)(B), WQBELs may only be relaxed where the action
is consistent with the state or authorized tribe's antidegradation policy.
It is important to note that these exceptions to the prohibition on antibacksliding as a result of a
change to water quality standards are only applicable to permits with water quality-based effluent
limitations. They are not applicable to relax limitations based on technology-based treatment
standards for the pollutants at issue.
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5.3 How should state and tribal water quality programs monitor and make attainment
decisions for the water quality criteria for bacteria in recreational waters?
Monitoring protocols and assessment methodologies for recreational waters may differ
depending upon the location of the waterbody, level of use, and program resources. The following
sections describe appropriate approaches in the development and implementation of state and tribal
monitoring and assessment programs for bacteria. Specifically, section 5.3.1 provides recommenda-
tions applicable to the period during which a state or authorized tribe maybe transitioning from fecal
coliforms to E. coli or enterococci. Section 5.3.2 focuses on general recommendations and examples
for evaluating monitoring data, assessing water quality, and determining attainment of water quality
standards.
5.3.1 While transitioning from fecal coliforms to E. coli and/or enterococci, how
should states and authorized tribes monitor and make attainment decisions for
their water quality criteria for bacteria?
Once a state or authorized tribe has adopted E. coli and/or enterococci into its water quality
standards and EPA has approved the new standards, states and authorized tribes should not delay
listing waterbodies for exceedances of water quality criteria for bacteria where historical data
(whether for fecal coliforms or for the newly adopted criteria) indicate an impairment. Further,
current Agency guidance and policy reject the notion that states and authorized tribes can avoid
listing waters in anticipation of a change to a state or authorized tribe's water quality standards.
Thus, if a state or authorized tribe has fecal coliform data that indicate a particular waterbody is not
attaining the applicable water quality standards, the waterbody should still be listed even if the state
or authorized tribe anticipates replacing its fecal coliform criteria with E. coli or enterococci in the
near future.
For waterbodies previously listed under section 303(d) for not attaining water quality
standards for fecal coliforms, EPA recommends that the waterbody continue to be included in the
state or authorized tribe's 303(d) impaired waters list for bacteria until sufficient^. co/z/enterococci
data are collected to either develop a Total Daily Maximum Load (TMDL) for bacteria or support
a de-listing decision. Where possible, states and authorized tribes may wish to assign these
waterbodies a lower priority ranking for development of TMDLs to accommodate the collection of
data on E. coli and/or enterococci. This would allow a waterbody listed for fecal coliforms to have
additional data collected for E. coli and/or enterococci and, if needed, a TMDL written based on
these newer criteria. In some instances states and authorized tribes may find that a waterbody not
meeting its previous fecal coliform criterion may meet the newer E. coli or enterococci criterion.
In a recent EPA-funded study conducted at Boston Harbor beaches in Massachusetts, it was found
that the enterococci criterion was met more often than the fecal coliform criterion (MWRA, 2001).
Proceeding hi this manner to accommodate the collection of additional data would also preclude the
need for a future TMDL revision if it had initially been written based on fecal coliforms.
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Where there is an immediate threat to public health or where a waterbody has been listed
under 303(d) on the basis of fecal coliform exceedances, and the waterbody is apriority due to court
order or state (or tribal) statute or regulations, states and authorized tribes should not delay
developing a TMDL. In these situations, the state or authorized tribe should develop the TMDL
using the fecal coliform criterion, and monitor progress toward meeting all bacterial water quality
standards, including the fecal coliform criterion (if it has been retained in the state or authorized
tribe's water quality standards during a transition period) and E. coli and/or enterococci. Because
data may not yet exist on the newly-adopted criteria, this would be one approach to meeting the
requirement that TMDLs be based on the water quality criterion in effect at the time of development.
If data collected over time indicate that the waterbody is meeting the E. co/z'/enterococci criteria, this
would constitute an acceptable measure of attainment of the TMDL. Alternatively, if later data show
a continuing problem under the E. co/z'/enterococci criterion that has not been adequately addressed
under the fecal coliform TMDL, revisions to the TMDL may be necessary once data on E.
co/z'/enterococci are collected.
After a state or authorized tribe adopts criteria for E. coli and/or enterococci, the amount of
data necessary to support a listing or de-listing decision will vary among states' and authorized
tribes' monitoring programs. This information should be contained either in states' and authorized
tribes' assessment and listing methodologies or in their water quality standards. The design of the
state or authorized tribe's monitoring program and the conclusi veness of the data collected will affect
the length of time before a state or authorized tribe is able to make regulatory decisions and take
appropriate actions. For example, if a state or authorized tribe routinely collects monitoring data and
finds within a relatively short period of time that the data collected indicate an exceedance of the
water quality criteria, EPA expects the state or authorized tribe to conclude that the waterbody is
impaired. Further, monitoring designs should reflect the way in which the state or authorized tribe's
water quality standards are expressed.
5.3.2 Once E. coli and/or enterococci have been adopted, how should recreational
waters be assessed and attainment determined for waters where the bacterio-
logical criteria apply?
Implementing water quality criteria for bacteria within a state or authorized tribe's
monitoring and listing program is a recurring topic within the ongoing dialogue EPA has with states,
authorized tribes* and other stakeholders, particularly during the recent development of the
Consolidated Assessment and Listing Methodology (USEPA, 2002a). The upcoming Version 1 of
the Methodology will address water quality monitoring strategies, data quality and data quantity
needs, and data interpretation methodologies. This effort is focused on helping states and authorized
tribes improve the accuracy and completeness of their CWA §303(d) lists and §305(b) reports as
well as streamlining these two reporting requirements. In addition, this document provides
recommendations for the listing and assessment of waters designated for primary contact recreation
and specifically refines previous recommendations on assessing attainment of the water quality
criteria for bacteria.
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States and authorized tribes have questioned how the criteria should be interpreted when
assessing waterbodies under CWA §305(b) and determining attainment under CWA §303(d). As
discussed earlier, EPA recommends states and authorized tribes adopt both a geometric mean and
a single sample maximum value. For states and authorized tribes that follow this approach,
determining attainment would be based on an evaluation of the water quality data as they relate to
both criteria components as specified in the state or authorized tribe's methodology.
Historically, states and authorized tribes have used simple descriptive statistics to determine
attainment consistent with these recommendations. Using this approach, the geometric mean of the
total number of samples taken over a certain period of time is calculated and the results compared
to the geometric mean component of the criterion. In addition, the monitoring data are compared
to the single sample maximum value to assure that no sample has exceeded the single sample
maximum value. Using simple descriptive statistics such as this, while acceptable to EPA, has
several drawbacks. Most notably, use of this approach assumes that the entire population was
representatively sampled, i.e., that the samples fully captured the range and variability of the ambient
concentrations existing over the period of time in which the samples were taken.
States and authorized tribes may also use what is known as inferential statistics (e.g.,
Students t-test, binomial and chi-square tests). The primary difference between the descriptive
statistical approach described above and inferential statistics is how they handle uncertainty (i.e.,
decision error) and the likelihood that the sample data represent the population they are used to
characterize. While descriptive statistics do not address uncertainty in the statistics used to describe
the population of interest, inferential statistics assume a potential for error in using sample data to
characterize the population and specifically address the likelihood that the sample data represent the
population by setting targets for reasonable decision error. States and authorized tribes that define
acceptable decision error have taken on a greater responsibility for monitoring programs, because
these states and authorized tribes are systematically defining—and, it is hoped, committing the
resources to collect—sufficient samples to support the tests.
Of these two general approaches, EPA prefers that, if sufficient data are collected, states and
authorized tribes use inferential statistical models due to the ability of these models to provide the
greatest certainty in making attainment decisions. Recommendations and discussions of the use of
different statistical approaches will be provided in EPA's Consolidated Assessment and Listing
Methodology (USEPA, 2002a) and are contained in EPA's Guidance for Choosing a Sampling
Design for Environmental Data Collection (USEPA, 2000). Using statistical approaches enables
the assessor to estimate, based on the samples taken and a specified confidence level, whether or not
the criterion is being attained. In order for these approaches to provide reliable results, a certain
amount of data must be collected as determined by data quality objectives, which in turn reflect
individual state or tribal standards. Alternatively, states and authorized tribes have employed other
statistical approaches. For example, some states and authorized tribes calculate confidence intervals,
the upper limits of which are compared to the single sample maximum to determine compliance with
that component of the criterion. Additional guidance on the use of alternate assessment approaches
will be provided in the Consolidated Assessment and Listing Guidance.
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In addition to these two approaches, states and authorized tribes may develop their own
approaches; however, any monitoring protocol developed by the state or authorized tribe should be
consistent with the relevant water quality standards. If the state or tribal water quality standards
define how the standards are to be interpreted, the state or authorized tribe must follow its prescribed
approach when assessing attainment. If the state or authorized tribe's standards are silent on h6w
to interpret data to make ambient attainment decisions, the state or authorized tribe should describe
its process. The state or authorized tribe may either follow EPA recommendations or develop
implementation procedures that are consistent with its water quality standards. For example, if a
state or authorized tribe's water quality criteria for bacteria consist of a geometric mean and a single
sample maximum and specify that the geometric mean is to be calculated based on five samples
taken over a thirty day period and that no sample may exceed the single sample maximum, the state
or authorized tribe's monitoring and assessment protocol should be consistent with these water
quality standards provisions. In some circumstances, states and authorized tribes may find that
revisions need to be made to their water quality standards to clarify how the water quality standards
will be interpreted for assessment and attainment determinations.
Many states' and authorized tribes' use information on bathing area restrictions and closures
to determine attainment with recreation-based water quality standards. This information often comes
from state, tribal, or local health departments and may be based on water quality monitoring,
calibrated rainfall alert curves, or precautionary information. Before using this information on use
restrictions and closures, it is important to document the basis for them. For example, the water
quality agency may want to verify that the health department uses indicators and thresholds that are
consistent with the state or authorized tribe's water quality standards.
In general, water quality-based bathing closures or restrictions that are consistent with the
state or authorized tribe's water quality standards and assessment methodology and are in effect
during the reporting period should be used as an indicator of water quality standards attainment.
There are some exceptions, however. Bathing areas subject to precautionary administrative closures
such as automatic closures after storm events of a certain intensity may not trigger an impairment
decision if monitoring data show an exceedance of applicable water quality standards has not
occurred. Similarly, closures or restrictions based on other conditions like rip-tides or sharks should
not trigger a nonattainment decision (USEPA, 2002a).
Regardless of the monitoring protocol used by a state or tribe, EPA recommends, at a
minimum, that primary contact recreation waters be monitored throughout the swimming season,
ideally on a weekly basis, to ensure human health is adequately protected, particularly waters that
are beach areas. EPA has prepared additional guidance contained in the National Beach Guidance
and Required Performance Criteria for Grants recommending monitoring approaches for identified
beach areas, as well as recommendations on how to use the data in making beach closures and
advisories. This document is available through EPA's Beach Watch web site at
www. epa. go v/waterscience/beaches. ,
EPA recognizes that there may be some waterbodies that merit less frequent monitoring.
These waterbodies may include those where public access is purposely restricted or limited by
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location and other waterbodies that are not likely to be used for primary contact recreation. Due to
resources or other constraints, states and authorized tribes may not be able to collect sufficient
samples for these waterbodies to perform a robust statistical analysis or to collect five samples within
a thirty day period to perform the recommended arithmetic analysis. In addition, for waterbodies
where infrequent sampling occurs, the few samples that are taken may have only been collected
during the swimming season.
Limited state or tribal resources may result in a state or tribe not being able to collect
sufficient samples to calculate a meaningful geometric mean for comparison with the criterion.
While EPA continues to encourage frequent monitoring of beaches and heavily-used recreation
areas, for those waterbodies that are remote or, for other reasons, rarely used, EPA recommends
states and authorized tribes develop monitoring protocols that describe how these waterbodies will
be monitored. States and authorized tribes should assure that any alternate monitoring protocols
developed are consistent with its water quality standards. In some cases, states and authorized tribes
may wish to revise their water quality standards to clarify these approaches. Alternatively, states and
authorized tribes may choose to specify their monitoring procedures in their CWA §303(d) listing
methodology. Regardless of where this information is contained, states and authorized tribes should
assure that their monitoring protocols and interpretation of the monitoring data are consistent with
the expression of the applicable water quality standards. Examples of types of monitoring
approaches that may be applied to infrequently used recreational waters are described in Table 5-1.
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Table 5-1. Monitoring approaches for less frequently used primary contact recreation
waters
Example #1
The sampling procedures for waters not identified as public or high use beaches specify that
water quality data collected over a period of time longer than 30 days may be used to calculate
geometric mean values. This may include calculation of seasonal geometric mean values or
annual geometric mean values in addition to using the single sample maximum component.
Example #2
The sampling procedures for remote waters not identified as public or high use beaches specify
the samples collected be compared to the single-sample maximum, serving as a trigger for
collecting five samples within a 30-day period. If routine monitoring finds an exceedance of a
single-sample maximum, then the state or tribe collects additional samples to calculate the
geometric mean. The state or tribe then uses the geometric mean to make an attain-
ment/nonattainment decision (i.e., both the geometric mean and the single-sample maximum
need to exceed the state or tribal standards for the waterbody to be identified as impaired under
CWA §§305(b) and 303(d)). This approach differs from Example #4 in that the assessment
decision is made only after additional data are collected.
Example #3
The sampling procedures for remote waters not designated as public beaches specify sampling
to occur periodically. On a rotating basin basis, sampling is conducted more intensively to
confirm periodic sampling findings.
Example #4
The sampling procedures for remote waters not identified as public or high use beaches are
compared to the single-sample maximum to determine attainment status, .if any of the samples
collected exceeds the single sample maximum, the waterbody is determined to be impaired.
This approach differs from Example #2 in that the assessment decision is made after com-
parison only with the single sample maximum. An exceedance results in a nonattainment
decision by the state or tribe as opposed to triggering more monitoring.
When considering the spectrum of different types of waterbodies designated for recreation,
approaches states and authorized tribes take to monitor their waterbodies may vary with the uses
assigned, since prioritization of monitoring resources maybe directed more toward the heavily used
recreation areas. For example, a state or authorized tribe may choose an inferential statistical
approach for the monitoring and evaluation of data for high use or identified bathing areas since
more data are likely to be collected in these areas. Alternatively, states and authorized tribes may
choose an approach that relies on fewer data for other waterbodies that are primary contact recreation
waters, but are not heavily used. (See section 4.1.1 for a discussion of how states and authorized
tribes may bifurcate their primary contact recreation use designations.) Regardless of the approach
used, states and authorized tribes should specify which monitoring approaches they will be using.
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Additionally, states and authorized tribes may find it useful to identify and provide to the public a
list of recreation waters and the frequency with which they will be monitored.
5.4 How should a state or authorized tribe's water quality program calculate allowable
loadings for TMDLs?
If a state or authorized tribe finds that its bacteriological criteria are not being attained, the ,
state or authorized tribe will need to develop a TMDL consistent with CWA §303(d). A TMDL I
establishes the allowable loadings for specific pollutants that a waterbody can receive without
exceeding water quality standards, thereby providing the basis for states and authorized tribes to
establish water quality-based pollution controls. A TMDL identifies the loading capacity for a
pollutant in a waterbody, the allocation of that pollutant to point and nonpoint sources contributing
the pollutant, and the seasonal variation and margin of safety so that the TMDL will result in
attaining the water quality standard.
For states and authorized tribes that have Adopted E. coli and/or enterococci into their water
quality standards, state and authorized tribe's water quality programs need to keep in mind the basis
and assumptions inherent in the development of the applicable water quality standard when
calculating a waterbody's total allowable load of the impairment-causing pollutant. The 19S6E. coli
and enterococci criteria are generally expressed both as a 30-day geometric mean and as a single
sample. The geometric mean is based on a comparison of the average summer exposure to the
illness rate; the single sample is a calculation of a daily exposure that is statistically related to the
geometric mean. The geometric mean characterizes an average exposure over 30 consecutive days;
the single sample characterizes exposure for any given day. The calculated allowable load will need
to reflect these, that is, the allowable load is a 30-day average load if based on the geometric mean,
and a single day load if based on the single sample. Because the comparison of bacteriological
indicator concentrations to illnesses was conducted on a daily basis, EPA recommends using the
daily average effluent flow for calculating loads based on the single sample.
EPA has published guidance on how to calculate loadings that attain water quality standards
for pathogens and pathogen indicators (USEPA, 2001 a). This guidance identifies analytical methods
that are appropriate to calculate these loads:
• Empirical approaches - Empirical approaches use existing data to
determine the linkage between sources and water quality targets, hi cases
where there are sufficient observations to characterize the relationship
between loading and exposure concentration across a range of loads, this
information could be used to establish the linkage directly, using, for
example, a regression approach.
• Simple approaches - Where the sole source of indicator bacteria are NPDES
permitted sources, these sources are often required to meet water quality
standards for indicator bacteria at the point of discharge or edge of the mixing
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zone, as specified in the state or tribal water quality standard. Simple dilution
calculations and/or compliance monitoring (for existing discharges) are often
adequate for this task.
• ' Detailed modeling-In cases where sources of bacteria are complex and
subject to influences from physical processes, a water quality modeling
approach is typically used to incorporate analysis of fate and transport issues.
Modeling techniques vary in complexity, using one of two basic approaches:
steady-state or dynamic modeling. Steady-state models use constant inputs
for effluent flow, effluent concentration, receiving water flow, and meteoro-
logical conditions. Generally, steady-state models provide very conservative
results when applied to wet weather sources. Dynamic models consider
time-dependent variation of inputs. Dynamic models apply to the entire
record of flows and loadings; thus the state or tribal water quality program
does not need to specify a design or critical flow for Use in the model. A daily
averaging time is suggested for bacteria. .
When detailed modeling is used, different types of models are required for accurate
simulation for rivers and streams as compared to lakes and estuaries because the response
is specific to the waterbody:
• Rivers and Streams. Prediction of bacteria concentrations in rivers and
streams is dominated by the processes of advection and dispersion and the
bacteria indicator degradation. One-, two-, and three-dimensional models
have been developed to describe these processes. Waterbody type and data
availability are the two most important factors that determine model
applicability. For most small and shallow rivers, one-dimensional models are
sufficient to simulate the waterbody's response to indicator bacteria loading.
For large and deep rivers and streams, however, the one-dimensional
approach falls short of describing the processes of advection and dispersion.
Assumptions that the bacteria concentration is uniform both vertically and
laterally are not valid. In such cases two- or three-dimensional models that
include a description of the hydrodynamics are used.
• . Lakes and Estuaries. Predicting the response of lakes and estuaries to
bacteria loading requires an understanding of the hydrodynamic processes.
Shallow lakes can be simulated as a simplified, completely mixed system
with an inflow stream and outflow stream. However, simulating deep lakes
with multiple inflows and outflows that are affected by tidal cycles is not a
simple task. Bacteria concentration prediction is dominated by the processes
of advection and dispersion, and these processes are affected by the tidal
flow. The size of the lake or the estuary, the net freshwater flow, and wind
conditions are some of the factors that determine the applicability of the
models.
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Given that most sources of bacteria are related to rainfall and higher river flow events, and
that water quality standards apply over a wide range of flows, states and authorized tribes will most
likely find that they need to calculate allowable loads for a wide variety of river flows. For this
reason, EPA recommends that states and authorized tribes use dynamic modeling to calculate these
loads. EPA recommends three dynamic modeling techniques to be used when an accurate estimate
of the frequency distribution of projected receiving water quality is required: continuous simulation,
Monte Carlo simulation, and log-normal probability modeling. These methods are described in
detail in EPA's guidance (USEPA, 2001; USEPA, 1991b). Models capable of simulating bacterial
concentrations are also described in EPA's guidance (USEPA, 2002b; USEPA, 1997).
In using dynamic modeling techniques, the state or authorized tribe will first develop,
calibrate, and verify a water quality model for existing loads, and then will try different scenarios of
load reductions until the water quality standards are attained. The wasteload allocations are then
directly calculated from the dynamic model using the permit derivation techniques described in the
Technical Support Document for Water Quality-based Toxics Control (USEPA, 1991b). The load
allocations are calculated from the percent reduction or pounds reduction used to attain the water
quality standard.
If a state or authorized tribe elects not to use a dynamic model, generally because there are
not sufficient data to develop such a model, then the program will need to use a steady state model
approach. This entails specifying a design flow for riverine systems to apply to the water quality
criterion in the standards. As discussed above, this flow will need to reflect the basis and
assumptions inherent in the development of the water quality criterion. Specifying the flow will also
be a challenge because the water quality standards must be attained over a range of flows, and where
the loadings are rainfall related, a critical drought flow approach will not always be representative
of the conditions when the standards might be exceeded. In lakes and estuaries, the flow is not as
responsive to rainfall events, and an average water circulation can be used.
Most TMDLs for bacteria will include intermittent or episodic loading sources (e.g., surface
runoff) that are rain-related and thus have serious water quality impacts under various flow
conditions. Sometimes, maximum impacts from episodic loading occur at high flows instead of at
low flows. For example, the elevated spring flows associated with snowmelt can contain high
concentrations of bacteria, especially when snowmelt originates from agricultural areas where
manure is spread in winter or from urban areas where residents practice poor pet curbing. As another
example, a small tributary may deliver bacteria to a river. The river's bacteria load is positively,
although not linearly, correlated with flow in the higher-order stream. (Both waters respond to
regional precipitation patterns.) The in-stream concentration from the tributary load will be affected
by the competing influences of increased load and increased dilution capacity, resulting in a peak
impact at some flow greater than base flow. If a point source was also present, a dual design
condition might be necessary.
For these reasons, if a state or authorized tribe elects to use a steady state model for a riverine
system, EPA recommends a dual design approach where the loadings for intermittent or episodic
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sources are calculated using a flow duration approach and the loadings for continuous sources are
calculated based on a low flow statistic. The flow duration approach has been used to establish a
number of TMDLs for rivers in Kansas (Stiles, 2001).
The flow duration approach calculates a load duration curve by first calculating the
cumulative frequency of the historical daily flow data over a period of time by the water quality
criterion. This in essence calculates the allowable load for every flow event, and portrays those loads
as the percentage of days that a loading can be exceeded without exceeding the water quality
criterion. The geometric mean criterion should be multiplied by the 30-day average flow, and the
single sample criterion should be multiplied by the daily flow. The flows used should reflect the
long term history of a river, although those periods may be shortened due to major disruptions to
rivers, such as reservoir operations or ground water depletion.
This approach requires the availability of long-term flow data to develop flow duration
curves as well as daily flow values associated with dates of sampling. Where there are no gauging
stations present at the sampling site, the state or authorized tribe may need to monitor flow itself or
rely on USGS-developed methods to estimate flow duration curves from ungauged areas.
The distribution of existing loads is calculated by multiplying the sampled quality data by
the daily flow on the date of sample, and plotting these calculations on the load duration curve
above. The state or authorized tribe can then compare the actual loadings to what is needed to attain
water quality standards. An example of this approach for Cowskin Creek near Oakville, Kansas, is
shown in Figure 1 (Stiles, 2001). While this example has used the state's existing fecal coliform
criterion, the approach is also applicable to either E. coli or enterococci criteria.
The overall reduction in loading necessary to attain the water quality standards is calculated
as the reduction from the distribution of the existing loadings to that of the loadings necessary to
attain the standards. This reduction also defines the necessary load reduction for nonpoint sources
in the Load Allocation and intermittent or episodic point sources in the Wasteload Allocation.
Continuous loadings, that is, sources that discharge at about the same level regardless of the
rainfall, often most greatly impact water quality under low-flow, dry-weather conditions, when
dilution is minimal (USEPA, 199la). For these sources, EPA recommends that the allowable
loading and Wasteload Allocations be calculated for the geometric mean as the product of the
geometric mean water quality criterion and the 30Q5 flow statistic (i.e., the highest 30-day flow
occurring once every five years), and for the single sample as the product of the single sample water
quality criterion and 1Q10 flow statistic (i.e., the highest one-day flow occurring once every 10
years) or the low flow specified in the state or tribal water quality standards, if one is so specified.
These flows reflect the characteristics of the criteria, that is, a 30-day average flow for the 30-day
average geometric mean and a one day flow for the single sample. By using extreme flow values,
the loading calculation ensures that the criteria are rarely exceeded. The 30Q5 is EPA's
recommendation for human health criteria for non-carcinogens and the 1Q10 is EPA's recommend-
ation for calculating loadings for criteria that represent a daily or hourly averaging period (USEPA,
1991b).
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700
KlCaiRE I. EXAMPLE OF A TMDL LOAD DURATION CURVE FOR BACTERIA
Cowskin Cr. nr Oatville
Bacteria TMDL
1000000
-. 100000
o
o
5
SB.
ffl
o
u.
0 10 20 30 40 50 60 70 80 90 100
Percent of Days Load Exceeded
-TMDL (2000)
TMDL {900}
Winter Data 1987-1999
* Spring Data 1987-1999
9 Summer/Fail Data 1987-1999
Source: Stiles, 2001
5.5 What analytical methods should be used to quantify levels of E. coli and enterococci in
ambient water and effluents?
The permit writer is responsible for specifying the analytical methods to be used for
monitoring in an NPDES permit. Typically, the methods specified are those cited in 40 CFR 136
in the standard conditions of the permit, unless other test procedures have been specified. In the case
of the development of permits for E. coli and enterococci, while EPA is planning to publish final
methods in 40 CFR 136 for E. coli or enterococci in the near future, methods do not yet exist in 40
CFR 136 for these constituents. Pursuant to 40 CFR 122.41(j)(4), permit writers have the authority
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to specify methods that are not contained in 40 CFR136. In addition to commercially available test
methods there are several EPA-approved methods permit writers may specify in permits, including
the mE and the mEI agar methods for enterococci and the modified mTEC and mTEC agar methods
for-E". coli.
5.6 How do the recommendations contained in this document affect waters designated for
drinking water supply?
Waterbodies that are used as public (drinking) water supplies are an important resource that
share many of the same human health concerns with recreational waterbodies. Both types of
waterbodies have a need to be protected against contamination by sources of fecal pollution. Like
recreational waterbodies, the primary route of exposure is through ingestion. However, unlike
recreation, consumption and other uses of water are intended and typically in much larger quantities.
While the Safe Drinking Water Act requires public water systems that are served by surface
water, or by groundwater under the direct influence of surface water, to provide a minimum level
of drinking water treatment to remove microbial pathogens, the treatment technologies used to
reduce microbial pathogens to safe levels in drinking water are not fully effective (i.e., they don't
remove every single microbe). Because these technologies remove only ^percentage of pathogens
from the ambient water, higher pollutant loads in the ambient water will result in higher absolute
levels of drinking water contamination and greater public health risk. Further, because drinking
water treatment technologies are subject to operator error and occasional equipment failure, the
prospect of treatment bypass poses a higher public health risk when the ambient water pollutant
loads are higher than when they are lower. Treatment bypass is the suspected cause of the
Milwaukee outbreak of cryptosporiasis in 1993 in which approximately 100 people died.
To date, EPA has not developed criteria recommendations under section 304(a) of the CWA
specifically aimed at the protection of drinking water sources from microbiological contaminants.
Some states and authorized tribes have adopted EPA's recommended water quality criteria for
bacteria to protect waters designated for drinking water supplies. EPA believes that, in the absence
of criteria specifically targeted to the microbiological organisms and exposure routes of concern in
drinking water supplies, this is an appropriate approach. Even though public water systems are
required to remove microbial pathogens to safe levels for consumption, the adoption of EPA's
recommended water quality criteria for bacteria to protect drinking water supplies provides an
additional and critical measure of public health protection. State and tribal adoption of EPA's
bacteriological criteria recommendations into their water quality standards for the protection of
drinking water supplies can provide a mechanism by which water quality may be maintained and
protected and sources of fecal pollution controlled.
EPA is contemplating the development of water quality criteria specifically targeted toward
the protection of waters designated for drinking water supplies. This is one area identified in EPA's
forthcoming Microbial Waterborne Disease Strategy that EPA intends to pursue.
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5.7 How do the recommendations contained in this document affect waters designated for
shellfishing?
EPA's criteria recommendations for the use of fecal coliform criteria to protect designated
shellfishing waters are contained in its Quality Criteria for Water 1986 (also known as the Gold
Book) (USEPA, 1986). While EPA continues to recommend states and authorized tribes use fecal
coliform criteria to protect shellfishing waters, EPA's current recommendation that states and
authorized tribes use enterococci for marine recreational waters and either enterococci or E. coli for
fresh recreational waters, are causing states and authorized tribes that have adopted these criteria to
now monitor for two different indicators. While EPA realizes that this may cause some
inconvenience and additional resources to conduct monitoring, data and information do not yet exist
that would support the use of E. coli or enterococci as criteria to protect waters designated for
shellfishing.
Thel986 E. coli and enterococci criteria were developed to protect against human health
effects, namely acute gastroenteritis, that maybe incurred due to incidental ingestion of water while
recreating. These criteria do not account for exposure that may be incurred by the consumption of
shellfish, and therefore, are not appropriate for waters designated for shellfish. If, at such time, data
and information are compiled that support the use of these indicator organisms in shellfishing waters,
EPA will revisit this issue and consider the development of a revised criterion that appropriately
takes into account the exposure pathways associated with the consumption of shellfish. In the
meantime, EPA continues to recommend the use of fecal coliforms for the protection of shellfishing
waters.
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References
Massachusetts Water Resources Authority (MWRA), prepared by Kelly Coughlin and Ann-Michelle
Stanley. 2001. Water Quality at Four Boston Harbor Beaches: Results of Intensive Monitoring,
1996 - 1999. Boston, MA. US EPA Grant # X991712-01.
Miescier, J. and V. Cabelli. 1982. Enterococci and Other Microbial Indicators in Municipal
Wastewater Effluent. Journal WPCF 54(12): 1599-1606.
Oregon Association of Clean Water Agencies. 1993. ACWA Enterococcus Study: Final Report.
Portland, OR.
Stiles, Thomas C. 2001. A Simple Method to Define Bacteria TMDLs in Kansas. Presented at the
WEF/ASIWPCA TMDL Science Issues Conference, March 7, 2001.
USEPA. 2002a. Version 1: Consolidated Assessment and Listing Methodology. U.S. Environ-
mental Protection Agency, Office of Water, Washington, D.C. Anticipate publication by time of
final document,
USEPA. 2002b. National Beach Guidance and Required Performance Criteria for Grants. U.S
Environmental Protection Agency, Office of Water, Washington, D.C. EPA 823-R-02-004.
USEPA. 2001. Protocol for Developing Pathogen TMDLs. U.S Environmental Protection Agency,
Office of Water, Washington, D.C. EPA 841-R-00-002.
USEPA. 2000. Guidance for Choosing a Sampling Design for Environmental Data Collection
(QA/G-5S), Draft. U.S. Environmental Protection Agency, Office of Environmental Information,
Washington, D.C.
USEPA. 1997. Compendium of Tools for Watershed Assessment and TMDL Development. U.S.
Environmental Protection Agency, Office of Water, Washington, D.C. EPA 841-B-97-006.
USEPA. 1996. U.S. EPA NPDES Permit Writers'Manual. U.S. Environmental Protection Agency,
Office of Water, Washington, D.C. EPA-833-B-96-003.
USEPA. 1991a. Guidance for water quality-based decisions: The TMDL process. U.S.
Environmental Protection Agency, Office of Water, Washington, D.C. EPA 440/4-91-001.
USEPA. 1991b. Technical Support Document for Water Quality-based Toxics Control. U.S
Environmental Protection Agency, Office of Water, Washington, D.C. EPA/505/2-90-001.
USEPA. 1986. Quality Criteria for Water 1986. U.S. Environmental Protection Agency, Office of
Water, Washington, D.C. EPA 440/5-86-001.
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Appendix A: Beaches Environmental Assessment and Coastal Health Act of
2000
An Act
To amend the Federal Water Pollution Control Act to improve the quality of coastal recreation
waters, and for other purposes.
Be it enacted by the Senate and House of Representatives of the United States of America in
Congress assembled,
SECTION 1. SHORT TITLE.
This Act may be cited as the "Beaches Environmental Assessment and Coastal Health Act of 2000".
SECTION 2. ADOPTION OF COASTAL RECREATION WATER QUALITY CRITERIA AND
STANDARDS BY STATES.
Section 303 of the Federal Water Pollution Control Act (33 U.S.C. 1313) is amended by adding at the
end the following:
(i) Coastal Recreation Water Quality Criteria.—
(1) Adoption by States.—
(A) Initial Criteria and Standards.—Not later than 42 months after the date of
the enactment of this subsection, each State having coastal recreation waters
shall adopt and submit to the Administrator water quality criteria and standards
for the coastal recreation waters of the State for those pathogens and pathogen
indicators for which the Administrator has published criteria under section
304(a).
(B) New or Revised Criteria and Standards.—Not later than 36 months after
the date of publication by the Administrator of new or revised water quality
criteria under section 304(a)(9), each State having coastal recreation waters shall
adopt and submit to the Administrator new or revised water quality standards for
the coastal recreation waters of the State for all pathogens and pathogen indica-
tors to which the new or revised water quality criteria are applicable.
(2) Failure of States to Adopt.—
(A) In General.—If a State fails to adopt water quality criteria and standards in
accordance with paragraph (1)(A) that are as protective of human health as the
criteria for pathogens and pathogen indicators for coastal recreation waters
published by the Administrator, the Administrator shall.promptly propose
regulations for the State setting forth revised or new water quality standards for
pathogens and pathogen indicators described in paragraph (1)(A) for coastal
recreation waters of the State.
(B) Exception.—If the Administrator proposes regulations for a State described
in subparagraph (A) under subsection (c)(4)(B), the Administrator shall publish
any revised or new standard under this subsection not later than 42 months after
the date of the enactment of this subsection.
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(3) Applicability.—Except as expressly provided by this subsection, the requirements
and procedures of subsection (c) apply to this subsection, including the requirement in
subsection (c)(2)(A) that the criteria protect public health and welfare.
SECTION 3. REVISIONS TO WATER QUALITY CRITERIA.
(a) Studies Concerning Pathogen Indicators in Coastal Recreation Waters.—Section 104 of the
Federal Water Pollution Control Act (33 U.S.C. 1254) is amended by adding at the end the following:
(v) Studies Concerning Pathogen Indicators in Coastal Recreation Waters.—Not later than
18 months after the date of the enactment of this subsection, after consultation and in cooperation
with appropriate Federal, State, tribal, and local officials (including local health officials), the
Administrator shall initiate, and, not later than 3 years after the date of the enactment of this
subsection, shall complete, in cooperation with the heads of other Federal agencies, studies to
provide additional information for use in developing—
(1) an assessment of potential human health risks resulting from exposure to pathogens
in coastal recreation waters, including nongastrointestinal effects;
(2) appropriate and effective indicators for improving detection in a timely manner in
coastal recreation waters of the presence of pathogens that are harmful to human health;
(3) appropriate, accurate, expeditious, and cost-effective methods (including predictive
models) for detecting in a timely manner in coastal recreation waters the presence of
pathogens that are harmful to human health; and
(4) guidance for State application of the criteria for pathogens and pathogen indicators to
be published under section 304(a)(9) to account for the diversity of geographic and
aquatic conditions.
(b) Revised Criteria.—Section 304(a) of the Federal Water Pollution Control Act (33 U.S.C. 1314(a)) is
amended by adding at the end the following:
(9) Revised Criteria for Coastal Recreation Waters.—
(A) In General.—Not later than 5 years after the date of the enactment of this
paragraph, after consultation and in cooperation with appropriate Federal, State,
tribal, and local officials (including local health officials), the Administrator
shall publish new or revised water quality criteria for pathogens and pathogen
indicators (including a revised list of testing methods, as appropriate), based on
the results of the studies conducted under section 104(v), for the purpose of
protecting human health in coastal recreation waters.
(B) Reviews.—Not later than the date that is 5 years after the date of publication
of water quality criteria under this paragraph, and at least once every 5 years
thereafter, the Administrator shall review and, as necessary, revise the water
quality criteria.
SECTION 4. COASTAL RECREATION WATER QUALITY MONITORING AND NOTIFICATION.
Title IV of the Federal Water Pollution Control Act (33 U.S.C. 1341 et seq.) is amended by adding at the
end the following:
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SEC. 406. COASTAL RECREATION WATER QUALITY MONITORING AND NOTIFICATION.
(a) Monitoring and Notification.—
(1) In General.—Not later than 18 months after the date of the enactment of this
section, after consultation and in cooperation with appropriate Federal, State,
tribal, and local officials (including local health officials), and after providing
public notice and an opportunity for comment, the Administrator shall publish
performance criteria for—
(A) monitoring and assessment (including specifying available methods
for monitoring) of coastal recreation waters adjacent to beaches or
similar points of access that are used by the public for attainment of
applicable water quality standards for pathogens and pathogen indica-
tors; and
(B) the prompt notification of the public, local governments, and the
Administrator of any exceeding of or likelihood of exceeding applicable
water quality standards for coastal recreation waters described in sub-
paragraph (A).
(2) Level of Protection.—The performance criteria referred to in paragraph (1)
shall provide that the activities described in subparagraphs (A) and (B) of that
paragraph shall be carried out as necessary for the protection of public health
and safety.
(b) Program Development and Implementation Grants.—
(1) In General.—The Administrator may make grants to States and local
governments to develop and implement programs for monitoring and notification
for coastal recreation waters adjacent to beaches or similar points of access that
are used by the public.
(2) Limitations.—
(A) In General.—The Administrator may award a grant to a State or a
local government to implement a monitoring and notification program
if—
(i) the program is consistent with the performance criteria pub-
lished by the Administrator under subsection (a);
(ii) the State or local government prioritizes the use of grant
funds for particular coastal recreation waters based on the use of
the water and the risk to human health presented by pathogens or
pathogen indicators;
(iii) the State or local government makes available to the Admin-
istrator the factors used to prioritize the use of funds under
clause (ii);
(iv) the State or local government provides a list of discrete
areas of coastal recreation waters that are subject to the program
for monitoring and notification for which the grant is provided
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that specifies any coastal recreation waters for which fiscal
constraints will prevent consistency with the performance
criteria under subsection (a); and
(v) the public is provided an opportunity to review the program
through a process that provides for public notice and an oppor-
tunity for comment.
(B) Grants to Local Governments.—The Administrator may make a
grant to a local government under this subsection for implementation of
a monitoring and notification program only if, after the lyear period
beginning on the date of publication of performance criteria under
subsection (a)(l), the Administrator determines that the State is not
implementing a program that meets the requirements of this subsection,
regardless of whether the State has received a grant under this sub-
section.
(3) Other Requirements.—
(A) Report.—A State recipient of a grant under this subsection shall
submit to the Administrator, in such format and at such intervals as the
Administrator determines to be appropriate, a report that describes—
(i) data collected.as part of the program for monitoring and
notification as described in subsection (c); and
(ii) actions taken to notify the public when water quality stan-
dards are exceeded.
(B) Delegation.—A State recipient of a grant under this subsection shall
identify each local government to which the State has delegated or
intends to delegate responsibility for implementing a monitoring and
notification program consistent with the performance criteria published
under subsection (a) (including any coastal recreation waters for which
the authority to implement a monitoring and notification program would
be subject to the delegation).
(4) Federal Share.—
(A) In General.—The Administrator, through grants awarded under this
section, may pay up to 100 percent of the costs of developing and
implementing a program for monitoring and notification under this
subsection.
(B) Nonfederal Share.—The non-Federal share of the costs of
developing and implementing a monitoring and notification program
maybe—
(i) in an amount not to exceed 50 percent, as determined by the
Administrator in consultation with State, tribal, and local gov-
ernment representatives; and
(ii) provided in cash or in kind.
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(c) Content of State and Local Government Programs.—As a condition of receipt of
a-grant under subsection (b), a State or local government program for monitoring and
notification under this section shall identify—
(1) lists of coastal recreation waters in the State, including coastal recreation
waters adjacent to beaches or similar points of access that ai'e used by the public;
(2) in the case of a State program for monitoring and notification, the process by
which the State may delegate to local governments responsibility for imple-
menting the monitoring and notification program;
(3) the frequency and location of monitoring and assessment of coastal rec-
reation waters based on—
(A) the periods of recreational use of the waters;
(B) the nature and extent of use during certain periods;
(C) the proximity of the waters to known point sources and nonpoint
sources of pollution; and
(D) any effect of storm events on the waters;
(4) (A) the methods to be used for detecting levels of pathogens and patho-
gen indicators that are harmful to human health; and
(B) the assessment procedures for identifying short-term increases in
pathogens and pathogen indicators that are harmful to human health in
coastal recreation waters (including increases in relation to storm
events);
(5) measures for prompt communication of the occurrence, nature, location,
pollutants involved, and extent of any exceeding of, or likelihood of exceeding,
applicable water quality standards for pathogens and pathogen indicators to—
(A) the Administrator, in such form as the Administrator determines to
be appropriate; and
(B) a designated official of a local government having jurisdiction over
land adjoining the coastal recreation waters for which the failure to meet
applicable standards is identified;
(6) measures for the posting of signs at beaches or similar points of access, or
functionally equivalent communication measures that are sufficient to give
notice to the public that the coastal recreation waters are not meeting or are not
expected to meet applicable water quality standards for pathogens and pathogen
indicators; and
(7) measures that inform the public of the potential risks associated with water
contact activities in the coastal recreation waters that do not meet applicable
water quality standards.
(d) Federal Agency Programs.—Not later than 3 years after the date of the enactment
of this section, each Federal agency that has jurisdiction over coastal recreation waters
adjacent to beaches or similar points of access that are used by the public shall develop
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and implement, through a process that provides for public notice and an opportunity for
comment, a monitoring and notification program for the coastal recreation waters that—
(1) protects the public health and safety;
(2) is consistent with the performance criteria published under subsection (a);
(3) includes a completed report on the information specified in subsection
(b)(3)(A), to be submitted to the Administrator; and
(4) addresses the matters specified in subsection (c).
(e) Database.—The Administrator shall establish, maintain, and make available to the
public by electronic and other means a national coastal recreation water pollution
occurrence database that provides—
(1) the data reported to the Administrator under subsections (b)(3)(A)(i) and
(d)(3); and
(2) other information concerning pathogens and pathogen indicators in coastal
recreation waters that—
(A) is made available to the Administrator by a State or local govern-
ment, from a coastal water quality monitoring program of the State or
local government; and
(B) the Administrator determines should be included.
(f ) Technical Assistance for Monitoring Floatable Material.— The Administrator
shall provide technical assistance to States and local governments for the development of
assessment and monitoring procedures for floatable material to protect public health and
safety in coastal recreation waters.
(g) List of Waters.—
(1) In General.—Beginning not later than 18 months after the date of publi-
cation of performance criteria under subsection (a), based on information made
available to the Administrator, the Administrator shall identify, and maintain a
list of, discrete coastal recreation waters adjacent to beaches or similar points of
access that are used by the public that—
(A) specifies any waters described in this paragraph that are subject to a
monitoring and notification program consistent with the performance
criteria established under subsection (a); and
(B) specifies any waters described in this paragraph for which there is no
monitoring and notification program (including waters for which fiscal
constraints will prevent the State or the Administrator from performing
monitoring and notification consistent with the performance criteria
established under subsection (a)).
(2) Availability.—The Administrator shall make the list described in paragraph
(1) available to the public through—
(A) publication in the Federal Register; and
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PnhJir Review Draft
Mav
(B) electronic media.
(3) Updates.—The Administrator shall update the list described in paragraph (1)
periodically as new information becomes available.
(h) EPA Implementation.—In the case of a State that has no program for monitoring
and notification that is consistent with the performance criteria published under sub-
section (a) after the last day of the 3year period beginning on the date on which the
Administrator lists waters in the State under subsection (g)(l)(B), the Administrator shall
conduct a monitoring and notification program for the listed waters based on a priority
ranking established by the Administrator using funds appropriated for grants under
subsection (i)—
(1) to conduct monitoring and notification; and
(2) for related salaries, expenses, and travel.
(i) Authorization of Appropriations.—There is authorized to be appropriated for
making grants under subsection (b), including implementation of monitoring and
notification programs by the Administrator under subsection (h), $30,000,000 for each of
fiscal years 2001 through 2005.
SECTION 5. DEFINITIONS.
Section 502 of the Federal Water Pollution Control Act (33 U.S.C. 1362) is amended by adding at the
end the following:
(21) Coastal Recreation Waters.—
(A) In General.—The term 'coastal recreation waters' means—
(i) the Great Lakes; and
(ii) marine coastal waters (including coastal estuaries) that are desig-
nated under section 303(c) by a State for use for swimming, bathing,
surfing, or similar water contact activities.
(B) Exclusions.—The term 'coastal recreation waters' does not include—
(i) inland waters; or
(ii) waters upstream of the mouth of a river or stream having an un-
impaired natural connection with the open sea.
(22) Floatable Material.—
«
(A) In General.—The term 'floatable material' means any foreign matter that
may float or remain suspended in the water column.
(B) Inclusions.—The term.'floatable material' includes—
(i) plastic;
(ii) aluminum cans;
(iii) wood products;
70
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PiihJir
T*vafi
(iv) bottles; and
(v) paper products.
(23) Pathogen Indicator.—The term 'pathogen indicator' means a substance that
indicates the potential for human infectious disease.
SECTION 6. INDIAN TRIBES.
Section 518(e) of the Federal Water Pollution Control Act (33 U.S.C. 1377(e)) is amended by striking
"and 404" and inserting "404, and 406".
SECTION 7. REPORT. .
(a) In General.—Not later than 4 years after the date of the enactment of this Act, and every 4
years thereafter, the Administrator of the Environmental Protection Agency shall submit to
Congress a report that includes—
(1) recommendations concerning the need for additional water quality criteria for
pathogens and pathogen indicators and other actions that should be taken to improve the
quality of coastal recreation waters;
(2) an evaluation of Federal, State, and local efforts to implement this Act, including the
amendments made by this Act; and
(3) recommendations on improvements to methodologies and techniques for monitoring
of coastal recreation waters.
(b) Coordination.—The Administrator of the Environmental Protection Agency may coordinate
the report under this section with other reporting requirements under the Federal Water Pollution
Control Act (33 U.S.C. 1251 et seq.).
71
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Jtfav 20/12
Appendix B: Summary of Epidemiological Research Conducted Since 1984
A recent review by Pruss1 of all studies since 1953 that examined the relationship between
swimming-associated gastroenteritis and water quality, indicated that nine separate marine studies
and at least two fresh water studies were conducted since the EPA studies were completed in 1984.
In this review, each of the later studies is summarized with regard to the size of the study, study
design, water quality indicator bacteria measured, and the results of the study with respect to
gastrointestinal illness. Some of the studies looked only at whether an association existed between
swimming and illness at a polluted beach or a non-polluted beach, while other studies attempted to
determine the relationship between increasing levels of poor water quality and the levels of
gastrointestinal illness associated with those increases. This review does not address studies that
examined non-enteric illnesses or infections unrelated to gastrointestinal disease. The intent of the
review is to carefully examine all of the studies conducted subsequent to the EPA studies and to
determine if they have a significant impact on the current water quality criteria for bacteria
recommended by the Agency.
Marine Water Studies
In 1987, Fattal et al.2 reported on a study of health and swimming conducted at beaches near
Tel-Aviv, Israel. The study design was the same that used by EPA. (In those studies described here
using the same design as the epidemiological studies conducted by EPA in support of its 1986 water
quality criteria for bacteria recommendations, it will state that the EPA design was used rather than
describing it in detail each time.) Beach water quality was measured using fecal coliforms,
enterococci, and E. coli. Three beaches with different water qualities were studied. Symptoms
among bathers were analyzed according to high and low categories of bacterial indicator densities
in the seawater. The high and low categories for fecal coliforms were above and below 50 colony
formmg units (cfu) per 100 ml. The limits for enterococci and E. coli were 24 cfu per 100 ml.
Excess illness was observed only in swimmers 0-4 years old at low categories of the indicators.
Significant differences in illness rates between swimmers and non-swimmers occurred only at high
indicator densities. Enterococci were the most predictive indicator for enteric disease symptoms.
hi 1990, Cheung and his co-workers3 reported on a health effects study related to beach water
pollution in Hong Kong. The basic EPA design was used in conducting this investigation. Nine
microbial indicators were examined as potentially useful measures of water quality. They included
fecal coliforms, £. coli, Klebsiella spp., fecal streptococci, enterococci, staphylococci,Pseudomonas
aeruginosa, Candida albicans, and total fungi. The study was carried out at nine beaches that were
polluted either by human sewage discharged from a submarine outfall or carried by storm water
drains into the beaches. Two of the beaches were contaminated mainly by livestock wastes.
Approximately nineteen thousand usable responses were obtained, of which about 77% were from
swimmers. The enterococci densities at the beaches ranged from 31 to 248 cfu per 100 ml. The
range for E. co/rwasfrom69to l,714cfuper 100ml. The overall gastrointestinal illness rates were
significantly higher in swimmers than in non-swimmers. Children under 10 years old were more
likely to exhibit gastrointestinal illness (GI) and highly credible gastrointestinal illness (HCGI)
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Mav 2002
symptoms than individuals older than 10 years. The best relationship between a microbial indicator
density and swimming-associated health effects was between E. coli and HCGI.
Health risks associated with bathing in sea water in the United Kingdom were described by
Balarajan et al.4 in 1991. This study also used the EPA design for their trials. The study was
conducted at one beach where 1,883 individuals participated (1,044 bathers and 839 non-bathers).
The methods used to measure water quality were not given. Ratios of illness in swimmers to non-
swimmers were developed. The rate of gastrointestinal illness was found to be significantly greater
in bathers than in non-bathers. The risk of illness increased with the degree of exposure, ranging
from 1.25 in waders, 1.31 in swimmers, to 1.81 in surfers or divers. The authors concluded that the
increase was indicative of a dose-response relationship.
Von Schirnding and others5 conducted a study to determine the relationship between
swimming-associated illness and the quality of bathing beach waters. A series of discrete,
prospective trials was carried out at a relatively clean and a moderately polluted beach following the
methodology used in the EPA studies. The beaches were situated on the Atlantic coast of South
Africa. The moderately polluted beach was affected by septic tank overflows, storm water run-off,
and feces-contaminated river water. A number of potential indicator organisms were measured
including enterococci, fecal coliforms, coliphages, staphylococci, and F-male-specific bacterio-
phages. A total of 1,024 people were contacted, of whom 733 comprised the final study population.
The moderately polluted beach was characterized by fecal coliforms and enterococci. The median
fecal coliform density was 77 cfu per 100 ml and the median enterococci density was 52 cfu per 100
ml. The median fecal coliform and enterococci densities at the relatively clean beach were 8 and 2
cfu per 100 ml, respectively. The rates for gastrointestinal symptoms were appreciably higher for
swimmers than non-swimmers at the more polluted beach as compared with the less polluted beach,
but the differences were not statistically significant, either for children less than ten years of age or
for adults. The lack of statistical significance may have been due in part to the uncertain sources of
fecal contamination.
In 1993, Corbett et al.6 conducted a study to determine the health risks of swimming at ocean
beaches in Sydney, Australia. The study used a design slightly modified from the EPA approach.
First, no one under the age of 15 was recruited for the study and, second, multiple samples were
taken at the time of swimming activity. The inclusion of families and social groups was minimized.
Water quality was measured using fecal coliforms and fecal streptococci. A total of 2,869
individuals participated in the study. Of this group, 32.2% reported that they did not swim. In
general, gastrointestinal symptoms in swimmers did not increase with increasing counts of fecal
bacteria. However, fecal streptococci were worse predictors of swimming-associated illness than
fecal coliforms. Although no relationship was observed between the measured indicators and
gastrointestinal illness, swimmers who swam for more than 30 minutes were 4.6 times more likely
to develop gastrointestinal symptoms than were those that swam for less than 30 minutes. The lack
of a relationship between increasing fecal coliform densities and gastrointestinal symptoms was
similar to results noted in the EPA marine and freshwater studies where increasing illness rates were
not associated with increasing fecal coliform densities.
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PtihtJc Review Draff
Ma
In 1994, Kay et al.7 conducted a series of four trials at bathing beaches in the Unitedl
Kingdom to examine the relationship between swimming-associated illness and water quality. Thel
design of this study differed from previous studies in that the study population was selected prior tol
each trial. On the trial date, half of the participants were randomly assigned to be swimmers, withl
the remaining participants were non-swimmers. Each swimmer swam in a designated area that was!
monitored by taking a sample every 30 minutes. Samples were analyzed for total and fecall
coriforms, fecal streptococci, Pseudomonas aeruginosa, and total staphylococci. The total numberl
of participants in the study was 1,112, of which 46% were selected as swimmers. All of the study|
volunteers were older than 18 years of age. Analysis of the data indicated that the rates oi
gastroenteritis were significantly higher in the swimming group than in the non-swimming group. I
Only fecal streptococci showed a significant dose-response relationship with gastroenteritis. The!
analysis suggested that the risk of gastroenteritis did not increase until bathers were exposed to about |
40 streptococci per 100 ml.
In 1995, Kueh et al.8 reported a second study conducted at Hong Kong beaches. Only two
beaches were examined in the second study, rather than the nine beaches examined in the 1990 Hong
Kong study. The study design for collecting health data was similar to that followed in the EPA |
studies. The ages of study participants ranged from 10 to 49 years of age. Unlike the EPA studies,
follow-up telephone calls were made two days after the swimming event rather than seven to 10
days. Another aspect of the Hong Kong study differing from the EPA studies was the collection of |
clinical specimens from ill participants with their consent. Stool specimens were analyzed for
Rotavirus, Salmonella spp., Shigella spp., Vibrio spp., and Aeromonas spp. Throat swabs were
examined for Influenza A and B; Parainfluenza virus types 1,2 and 3; Respiratory Syncytial Virus,
and Adenovirus. Water samples were examined for E. coli, fecal coliforms, staphylococci,
Aeromonas spp., Clostridiumperfringens, Vibrio cholera, Vibrioparahemolyticus, Vibrio vulnificus,
Salmonella spp., and Shigella spp. A total of 18,122 individuals participated in the study. Although
the levels of indicator densities were not reported for the beaches, the gastrointestinal illness rates
were significantly higher at the more polluted beach. This study did not find a relationship between
E. coli and swimming-associated illness as had been found in the original Hong Kong study. This
may have been, as pointed out by the authors, due to the fact that only two beaches were examined
rather than nine. The cause of the infections could not be ascertained from the clinical specimens
obtained from ill individuals.
In 1998, McBride et al.9 reported prospective epidemiological studies on the possible health
effects from sea bathing at seven New Zealand beaches, A total of 1,577 and 2,307 non-swinimers
participated in the studies. Although the EPA study design was used, it was slightly modified in that
follow-up interviews were conducted three to five days after the swimming event rather than the
seven to 10 days used in the U.S. studies. Fecal coliforms, E. coli, and enterococci were used to
measure water quality. The results of the study showed that enterococci were most strongly and
consistently associated with illness risk for the exposed groups. Risk differences between swimmers
and non-swimmers were significantly increased if swimmers stayed in the water for more than 30
minutes as compared to those in the water less than 30 minutes. The risk differences were slightly
greater for paddlers than for swimmers.
74
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The most recent study of possible adverse health effects associated with swimming in marine
waters was conducted at beaches on Santa Monica Bay, California, by Haile and others.10 The
objective of this study was to determine if excess swimming-associated illness could be observed
in swimmers exposed to waters receiving discharges from a storm drain. The study design was
patterned after the U.S. EPA studies. Water samples were taken at ankle depth and collected from
sites at the storm drain, 100 yards up-coast, and 100 yards down-coast. Samples were also collected
400 yards up-coast or down-coast of the storm drain, depending on which location would be used
as a control area. The samples were analyzed for totalcoliforms, fecal coliforms, enterococci, and
E. coli.. One sample was collected each Friday, Saturday, and Sunday during the study period at the
mouth of the storm drain and analyzed for enteric viruses. Subjects of all ages participated in the
study. A total of 11,686 subjects volunteered to take part in the study. The results of the study with
regard to -associations between bacterial indicators and health outcomes were presented in terms of
thresholds of bacterial densities, which were somewhat arbitrarily chosen. No positive associations,
as measured by risk ratios, were observed for E. coli at bacterial density thresholds of 35 and 70 cfu
per 100 ml. A less arbitrary analysis using a continuous model showed more positive associations,
especially for enterococci. The model for enterococci indicated positive associations with fever, skin
rash, nausea, diarrhea, stomach pain, coughing, runny nose, and highly credible gastrointestinal
illness. The associations of symptoms with indicators were very weak in the case of E. coli and fecal
coliforms. However, the authors found that the total coliform to fecal coliform ratio was very
informative. Using a ratio of 5.0 as a threshold, diarrhea and highly credible gastrointestinal illness
were associated with a lower total coliform to fecal coliform ratio regardless of the absolute level
of fecal coliforms. When then: analysis was restricted to subjects where the total coliforms exceeded
5,000 cfu per 100 ml, significantly higher risks were detected for most outcomes. One of the general
conclusions of the study was that excess gastrointestinal illness is associated with swimming in
feces-polluted bathing water.
Fresh Water Studies
In 1985, Seyfried et al.11 reported on a prospective epidemiological study of swimming-
associated illness in Canada. These investigations used the EPA methodology in carrying out the
study. Water quality was measured with the following bacterial indicators of swimming water
quality: fecal coliforms, fecal streptococci, heterotrophic bacteria, 'Pseudomonas aeruginosa, and
total staphylococci. A total of 4,537 individuals participated in the study, of which 2,743 were
swimmers and 1,794 were non-swimmers. Swimmers were found to have significantly higher
gastrointestinal illness rates than non-swimmers, and swimmers under the age of 16 had substantially
higher rates than swimmers 16 and older. Logistic regression analysis was performed to determine
the best relationship between water quality indicators and swimming-associated illness. A small
degree of correlation was observed between fecal streptococci and gastrointestinal illness. The best
correlation was between gastrointestinal illness and staphylpcoccus densities.
In 1989, Ferley et al.n described an epidemiological study conducted in France that examined
health effects associated with swimming in a freshwater river. A total of 5,737 individuals
participated in the study. The quality of the water was measured by assaying for fecal coliforms,
75
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Pr/fifff
Drat
fecal streptococci, and Pseudomonas aeruginosa. The study design for collecting health data was!
unique. The maximum latency period for the illness category groups examined in this study wasl
three days. Illnesses occurring during the course of the study were assigned to the nearest day within!
the latency period on which a sample was taken. A weighted linear regression was performed to I
relate gastrointestinal morbidity incidence rates to different levels of exposure to indicator bacteria, f
Significant excess gastrointestinal illness was observed in swimmers. Furthermore, regression of
gastrointestinal illness incidence to the concentration of indicator organisms showed a good I
relationship between swimming-associated illness for both fecal coliforms and fecal streptococci.
The strongest correlations occurred between incidence rates of acute gastrointestinal disease and
fecal streptococci densities. The authors indicated that their definition of fecal streptococci [
essentially included what the EPA studies call enterococci.
76
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References
1. Pruss, A. 1998. Review of epidemiological studies on health effects from exposure to
recreational water. Int. J. Epidemiol. 27:1-9.
2. Fattal, B. 1987. The association between seawater pollution as measured by bacterial
indicators and morbidity among bathers at Mediterranean bathing beaches of Israel. Chemo-
sphere 16:565-570.
3. Cheung, W.H.S., K.C.K. Chang, and R.P.S. Hung. 1990. Health effects of beach water
pollution in Hong Kong. Epidemiol. Infect. 105:139-162.
4. Balarajan, R., V. Soni Raleigh, P. Yuen, D. Wheeler, D. Machin, and R. Cartwright. 1991.
Health risks associated with bathing in sea water. Brit. Med. J. 303:1444-1445.
5. Von Schirnding, Y.E.R., R. Kfir, V. Cabelli, L. Franklin, and G. Joubert. 1992. Morbidity
among bathers exposed to polluted seawater - A prospective epidemiological study. South
African Medical J. 81:543-546.
6. Corbett, S.J., J.L. Rubin, G.K. Curry, and D.G. Kleinbaum. 1993. The health effects of
swimming at Sydney beaches. Am. J. Public Health 83:1701-1706.
7. Kay, D., J.M. Fleisher, R.L. Salmon, F. Jones, M.D. Wyer, S.F. Godfree,Z. Zelenauch-
Jacquotte, and R. Shore. 1994. Predicting likelihood of gastroenteritis from sea bathing: results
from randomized exposure. Lancet 344:905-909.
8. Kueh, C.S.W., T-Y Tarn, T.W. Lee, S.L. Wang, O.L. Lloyd, I.T.S. Yu, T.W. Wang, J.S. Tarn,
and D.CJ. Bassett. 1995. Epidemiological study of swimming-associated illnesses relating to
bathing-beach water quality. Wat. Sci Tech. 31:1-4.
9. McBride, G.B., C.E. Salmond, D.R. Bandaranayake, SJ. Turner, G.D. Lewis, and D.G. Till.
1998. Health effects of marine bathing in New Zealand. Int. J. of Environ. Health Res. 8:173-
189.
10. Haile, R.W., J.S. Witte, M. Gold, R. Cressey, C. McGee, R.C. Millikan, A. Glasser, N.
Harawa, C. Ervin, P. Harmon, J. Harper, J. Dermand, J. Alamillo, K. Barrett, M. Nides, and G.
Wang. 1999. The health effects of swimming in ocean water contaminated by storm drain
runoff, Epidemiol. 10:355-363.
11. Seyfried, P.L., R.S. Tobin, N.E. Brown, and P.F. Ness. 1985. A prospective study of
swimming-related illness U. Morbidity and the Microbiological Quality of Water. Am. J. Public
Health 75:1071-1075.
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12. Ferley, J.P., D. Zmirou, F. Balducci, B. Baleux, P. Fera, G. Larbaigt, E. Jacq, B.
Moissonnier, A. Blineau, and J. Boudot. 1989. Epidemiological significance of microbiological
pollution criteria for river recreational waters. Int. J. of Epidemiol. 18:198-205.
81
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Pr/hfir Review Kraft
Appendix C: Sample Calculations of E. Co///Enterococci Water Quality
Criteria Associated with Different Risk Levels
Fable B.I EPA's Recommended 1986 Water Quality Criteria for Bacteria
Indicator
reshwater
enterococci
£. co/7
narine water
enterococci
Illness Rate
(per 1000)
Geometric
Mean Density
8
8
19
33
126
35
Single Sample Maximum Allowable Density
Designated
Beach Area
75% C.L.*
62
235
104 .
Moderate Full
Body Contact
Recreation
82% C.L.
78
298
158
Lightly Used
Full Body Con-
tact
90% C.L.
107
410
276
Infrequently
Used Full Body
Contact
95% C.L.
151
576
501
*C.L. = confidence level. While more appropriately referred to as "percentiles", these values were originally described as
"confidence levels" in EPA's 1986 criteria document.
Source: USEPA, 1986.
Regression Equations Used to Calculate Geometric Mean Density:
Freshwater
E. coli:
Enterococci:
Marine Water
Enterococci:
log (geometric mean) = (0.1064 x illness rate) + 1.249
log (geometric mean) = (0.1064 x illness rate) + 0.668
log (geometric mean) = (0.0827 x illness rate) - 0.0164
Equations Used to Calculate Single Sample Maximum Values:
Log (SSM) = (Log (Geometric Mean Value)) + ((Confidence Level Factor) x (Log Standard
Deviation))
Confidence Level Factors:
Log Standard Deviation:
75% = 0.68
82% = 0.94
90%'= 1.28
95% =1.65
Freshwater = 0.4
Marine Water = 0.7
82
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Water Quality Criteria for Bacteria for Fresh Recreational Waters
Enterococci Criteria
Illness Rate
(per 1000)
8
9
10
11
12
13
14
Geometric
Mean Density
33
42
54
69
88
112
144
Single Sample Maximum Allowable Density
Designated Beach
Area 75% C.L.
62
79
100
128
164
209
267
Moderate Full Body
Contact Recreation
82% C.L.
78
100
128
163
208
266
340
Lightly Used Full
Body Contact
90% C.L.
107
137
175
224
286
365
467
Infrequently Used
Full Body Contact
95% C.L.
151
193
246
315
402
514
656
E. coli Criteria
Illness Rate
(per 1000)
8
9
10
11
12
13
14
Geometric
Mean Density
126
206
206
263
336
429
548
Single Sample Maximum Allowable Density
Designated Beach
Area 75% C.L.
235
300
383
490
626
799
1021
Moderate Full Body
Contact Recreation
82% C.L.
487
381
487
622
795
1016
1298
Lightly Used Full
Body Contact
90% C.L.
669
524
669
855
1092
1396
1783
Infrequently Used
Full Body Contact
95% C.L.
576
736
941
1202
1536
1962
2507
83
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Pr/hfff Jf0vlf>w Til-nft
Water Quality Criteria for Bacteria for Marine Recreational Waters
Enterococci Criteria
Illness Rate
(per 1000)
8
9
10
11
12
13
14
15
16
17
18
19
Geometric
Mean Density
4
5
6
8
9
11
14
16
20
24
29
35
Single Sample Maximum Allowable Density
Designated Beach
Area 75% C.L.
13
16
19
23
28
33
40
49
59
71
86
104
Moderate Full Body
Contact Recreation
82% C.L.
20
24
29
35
42
51
61
74
90
108
131
158
Lightly Used Full
Body Contact
90% C.L.
34
42
50
61
73
89
107
129
156
189
228
276
Infrequently Used
Full Body Contact
95% C.L.
63
76
91
110
133
161
195
235
284
343
415
501
84
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Public Review Draff
Appendix D: Summary of Water Quality Criteria for Bacteria Adopted by
States, Authorized Tribes, and Territories
STATES
WATER QUALITY CRITERIA1
COMMENTS
Region I
Connecticut
Inland, coastal and marine surface waters
(A/SA and B/SB for enterococci):
GM = 33cfu/100 ml
S.M. = 61cfu/100 ml
Enterococci criteria do not apply to all
primary contact recreation waters,
only established bathing waters.
Maine
Freshwater (E. coif)
Class B:
GM = 64 cfu/lOOml
S.M.= 427 cfu/100 ml
Class C:
GM = 142 cfu/lOOml
S.M. = 949 cfu/100 ml
Marine Waters (enterococci)
Class SB
GM = 8 cfu/100 ml
S.M. = 54 cfu/100
Class SC
GM=14 cfu/100 ml
S.M. =94 cfu/100
Seasonal for both Class SB and SC:
May 15-Sept. 30 .
New Hampshire
Fresh Waters (E. coif)
Class A
GM = 47cfu/100ml
S.M. = 153 cfu/100 ml
Class B
'GM=126cfu/100ml
S.M. = 406 cfu/100 ml
Class B (beaches)
GM = 47cfu/100ml
S.M. = 88 cfu/100 ml
Marine Waters (enterococci)
Class A
GM = 35 cfu/100 ml
S.M. = 104 cfu/100, for "beaches" S.M. = 88
cfu/100
Class B
GM = 35 cfu/100 ml
S.M. = 104 cfu/100, for "beaches" S.M. = 88
cfu/100
85
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PtiMir
Draft
May ?,OQ2
STATES
Vermont
WATER QUALITY CRITERIA1
Class A (E. coli)
S.M. = 18 cfu/100 (E. coli)
Class B (E. coli)
S.M. =77 cfu/100 (E. coli)
COMMENTS
Secretary may waive October 31-
April 1.
Region II
New Jersey
PR
Fresh waters (enterococci)
FW2:
GM = 33 cfu/100 ml
S.M. = 61 cfu/100
Salt and estuarine waters (SE1) and saline
coastal waters (SC) (enterococci):
GM = 35 cfu/100 ml
S.M. = 104/100 ml
Class SA: May not be altered except by natural
causes
Class SB (enterococci): GM = 35 cm/100 ml
for "intensely used waters"
The criteria has only been adopted for
certain marine waters (Class SB).
Other marine waters (Class SC, which
includes primary contact recreation)
do not include these criteria.
Region III
Delaware
Fresh Waters (enterococci):
GM= 100 cfu/100 ml
Marine Waters (enterococci):
GM = 10 cfu/100 ml
Region IV
Tennessee
Recreation waters (E. coll):
GM= 126 cfu/100 ml
Region V
Indiana
Michigan
Total Body Contact Recreation
(E. coli):
GM = 125 cfu/100 ml
S.M.= 235 cfu/100 ml
All waterbodies (E. coli):
GM= 130 cfu/100 ml
S.M. = 300 cfu/100 ml
Seasonal: April - October
The criteria apply, at mirumum,
May 1 -Oct. 31
The E. coli value is used for ambient
monitoring and fecal coliforms used
for establishing effluent limitations.
86
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Public
Mnv 7MJ.
STATES
WATER QUALITY CRITERIA1
COMMENTS
Ohio
Lake Erie & Ohio R. (E. coli):
GM= 126 cfu/100 ml
No more than 10% samples exceed 235
cm/100 ml
Rest of stated, coli):
primary contact:
GM= 126 cfu/100 ml
No more than 10% samples exceed 298
cfu/100 ml
secondary contact:
GM= 126 cfu/100 ml
No more than 10% samples exceed 576
cfu/100 ml
Fond du Lac Band
of Lake Superior
Chippewa
Primary Contact Recreation, Secondary
Contact Recreation
(E. coli)
GM= 126 cfu/100 ml
When fewer than five samples
collected in 30-day period, E. coli is
not to exceed 235 cfu/100 ml in any
single sample.
Region VI
Oklahoma
Primary Body Contact Recreation
(E, coli)
GM= 126 cfu/100 ml
S.M. = 235 cfu/100 ml (lakes and high use
waterbodies)
S.M. = 406 cfu/100 ml
(enterococci)
GM = 33 cfu/100 ml
S.M. = 61 cfu/100 ml (lakes and high use
waterbodies)
S.M. = 108 cfu/100 ml
Applies during recreation period of
May 1 to September 30.
Texas
Fresh Waters (E, coli)
Contact Recreation Use
GM= 126 cfu/100 ml
S.M. = 394 cfu/100 ml
Noncontact Recreation Use
GM = 605 cfu/100 ml
Marine Waters (enterococci)
Contact Recreation Use
GM =35 cfu/100 ml
S.M. =.89 cfu/100 ml
Noncontact Recreation Use
GM= 168 cfu/100 ml
87
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c RP.VJPW Draft
STATES
WATER QUALITY CRITERIA1
COMMENTS
Acoma Pueblo
Primary Contact Recreation
(E. coli)
GM= 126 cfu/100 ml
S.M. = 235 cfii/100 ml (Acomita Lake and high
use waterbodies)
S.M. = 406 cfu/100 ml (all other ceremonial
and recreation use areas)
(enterococci)
GM = 33cMOOml
S.M. = 61 cfu/100 ml (Acomita Lake and high
use waterbodies)
S.M. = 108 cfu/100 ml (all other ceremonial
and recreation use areas)
Partial Body Contact
lOx criteria specified for primary contact rec-
reation
Compliance for primary contact rec-
reation based on meeting the criteria
for one of the indicators.
Region VIII
Colorado
Recreation Use la (E. coli)
GM= 126 cfu/100 ml
Recreation Use Ib (E. coli)
GM = 205 cfu/100 ml
Secondary Contact Recreation Use
(E. coli)
GM = 630 cfu/100 ml
Ft. Peck
Assiniboine and
Sioux Tribes
Primary Contact Recreation Use
(E. coli)
GM= 126 cfu/100 ml
S.M. = 235 cfu/100 ml
Secondary Contact Recreation Use
(E. coli)
GM = 126 cfu/100 ml
S.M. = 406 cfu/100 ml
Region IX
Arizona
Full Body Contact (Kcoli)
GM= 130 cfu/100 ml
S.M. = 580 cfu/100 ml
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PtiMir
7)»V7/
Mm, MM
STATES
WATER QUALITY CRITERIA1
COMMENTS
California
REGIONAL BOARD 2
Salt Waters REC-1 (enterococci):
Geometric mean (GM) =35 cm/100 ml
Single sample maxima (S.M.) range from 104-
500 based on frequency of use
Fresh Waters REC-1:
Enterococci
GM=33cfu/100ml
S.M. range from 61-151 based on frequency of
use
E. coli
GM=126cr¥100ml
S.M. range from 235-576 based on frequency
of use
REGIONAL BOARD 7
REC-1:
Enterococci
GM = 33cfu/100ml
S.M. = 100cru/100ml
E. coli
GM = 126cfu/100ml
S.M.=400crV100ml
REC-2:
Enterococci
GM = 165 cm/100 ml
S.M. = 500cfu/100ml
E. coli
GM = 630 cm/100 ml
S.M. = 2000 cm/100 ml
Colorado River
REC-1:
Enterococci
S.M. = 61cMOOml
E.coll
S.M. = 235 cm/100 ml
REC-2:
Enterococci
S.M. = 305cfu/100ml
E. coli
S.M. = 1175cr¥100ml
Regional Boards 2,7, and 9 have
adopted criteria based on EPA's rec-
ommended indicators. The other 6
Boards have not.
The geometric means specified by
Regional Board 7 for the REC-1 and
REC-2 uses also apply to the
Colorado River.
89
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Pnhlir Review J)rafi
Ma
y
STATES
WATER QUALITY CRITERIA1
COMMENTS
California
(cont.)
REGIONAL BOARD 9
Salt Waters REC-1 (enterococci):
GM=35 cfu/100 ml
S.M. range from 104-500 based on frequency
of use
Fresh Watef s REC-1
Enterococci
GM=33 cfu/100 ml
S.M. range from 61-151 based on frequency of
use
E. coli
GM =126 cfu/100 ml
S.M. range from 235-576 based on frequency
of use
STATE OCEAN PLAN (enterococcH
GM = 24 cfii/100 ml for 30 day period
GM = 12 cfu/100 ml for 6 month period
Hawaii
Marine Waters (enterococci):
GM = 7 cfu/100 ml
American Samoa
For all marine waters (enterococci);
GM = 33 cfu/100 ml
Open Ocean:
S.M. = 276 cm/100 ml
Embayments:
S.M. = 104 or 124 cfu/100 ml
Open Coastal Waters:
S.M. = 124 cfu/100 ml
CNMI
Class AA (enterococci):
GM = 35 cfu/100 ml
Class A (enterococci):
GM= 125 cfu/100 ml
One element of the Class A use is
primary contact recreation.
Hoopa Valley Tribe
Primary Contact Recreation (enterococci)
GM= 16 cfu/100 ml
S.M. = 35 cfu/100 ml
Secondary Contact Recreation (enterococci)
GM = 33 cfu/100 ml
S.M. = 150 cfu/100 ml
Tribe has not yet completed WQS
adoption process.
90
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Puhlfc Review Draft
May ?M2
STATES
WATER QUALITY CRITERIA1
COMMENTS
Region X
Idaho
Primary Contract Recreation
(E. coli)
GM=126cMOOml
S.M. = 406cfu/100ml
Secondary Contact Recreation
(E. coli)
GM=126cMOOml
S.M. = 576cfu/100ml
Oregon
Fresh and Estuarine Waters (E. coli)
GM=126cfu/100ml
Washington
Fresh waters (enterococci)
Water Contact Recreation
GM = 33cfu/100ml
S.M. = 61cfu/100
Marine Waters (enterococci)
In the process of adopting
Water Contact Recreation
GM = 35cfu/100ml
S.M. = 104/100 ml
Colville
Confederated Tribes
Class I (enterococci)
GM = 8cfu/100ml
S.M. = 35cfu/100ml
Class II (enterococci)
GM = 16cru/100ml
S.M. = 75cfu/100ml
Class HI (enterococci)
GM = 33cfo/100ml
S.M. = 150cfu/100ml
Warm Springs
Public and private domestic water supply,
Water Contact Recreation, Wildlife and
Hunting, Fishing, Boating/Rafting (E. coli)
GM=126cfu/100ml
S.M.=406cfu/100ml
Confederated Tribes
oftheUmatilla
Indian Reservation
of Oregon
Recreation (E. coli)
GM=126cMOOml
S.M.=406cfu/100ml
91
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