823-R-07-007
REPORT OF THE EXPERTS SCIENTIFIC WORKSHOP ON CRITICAL
RESEARCH NEEDS FOR THE DEVELOPMENT OF NEW OR REVISED
RECREATIONAL WATER QUALITY CRITERIA
DRAFT
EXECUTIVE SUMMARY
BY WORKGROUP CHAIRS
Airlie Center
Warrenton, Virginia
March 26-30, 2007
U.S. Environmental Protection Agency
Office of Water
Office of Research and Development
July 13, 2007
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U.S. Environmental Protection Agency Experts Scientific Workshop
DISCLAIMER
This document has been reviewed in accordance with U.S. Environmental Protection Agency
(EPA) policy and approved for publication. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use. Furthermore, this document is a
summary of the views of the individual workgroup chairs and approval for publication does not
signify that the contents reflect the views of the Agency and no official endorsement should be
inferred.
ACKNOWLEDGMENTS
EPA would like to thank the experts and others who participated in the Experts Scientific
Workshop on Critical Research Needs for the Development of New or Revised Recreational
Water Quality Criteria. Their dedication and hard work at and following the workshop to
produce the proceedings are greatly appreciated. EPA would also like to thank the workgroup
chairs who worked collaboratively after the workshop to produce this Executive Summary.
Workshop Chair:
Denise Keehner, USEPA
Workshop Experts:
* Nicholas Ashbolt, USEPA
Thomas Atherholt, New Jersey Department of Environmental Protection
Michael Beach, Centers for Disease Control and Prevention
Bart Bibler, Florida Department of Health
* Alexandria Boehm, Stanford University, California
Rebecca Calderon, USEPA
Jack Colford, University of California, Berkeley
Elizabeth Doyle, USEPA
Alfred Dufour, USEPA
* Lee Dunbar, Connecticut Department of Environmental Protection
Lora Fleming, University of Miami School of Medicine and Rosenstiel School of Marine and
Atmospheric Sciences, Florida
Donna Francy, U.S. Geological Survey
Roger Fuji oka, University of Hawaii, Manoa
Toni Glymph, Wisconsin Department of Natural Resources
Mark Gold, Heal the Bay, California
Charles Hagedorn, Virginia Tech
* Joel Hansel, USEPA
Lawrence Honeybourne, Orange County Health Care Agency, Santa Ana, California
* Paul Hunter, University of East Anglia, U.K.
* Dennis Juranek, Centers for Disease Control and Prevention (retired)
David Kay, University of Wales, U.K.
Sharon Kluender, Wisconsin State Laboratory of Hygiene
Erin Lipp, University of Georgia
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U.S. Environmental Protection Agency Experts Scientific Workshop
Graham McBride, National Institute of Water and Atmospheric Research, New Zealand
Charles McGee, Orange County Sanitation District, California
Samuel Myoda, Delaware Department of Natural Resources
Charles Noss, USEPA
Robin Oshiro, USEPA
James Pendergast, USEPA
Mark Pfister, Lake County Health Department, Illinois
John Ravenscroft, USEPA
William Robertson, Water, Air and Climate Change Bureau, Health Canada
Stephen Schaub, USEPA
Mark Sobsey, University of North Carolina, Chapel Hill
Jeffrey Seller, Seller Environmental, California
Michael Tate, Kansas Department of Health and Environment
Peter Teunis, RIVM (National Institute of Public Health and the Environment), Netherlands
Gary Toranzos, University of Puerto Rico, Rio Piedras
Timothy Wade, USEPA
John Wathen, USEPA
* Stephen Weisberg, Southern California Coastal Water Research Project
David Whiting, Florida Department of Environmental Protection
Richard Zepp, USEPA
* Workgroup chairs and authors of this Executive Summary
Workshop Organizing Committee:
Shari Barash, USEPA
Rebecca Calderon, USEPA
Elizabeth Doyle, USEPA
Alfred Dufour, USEPA
Samantha Fontenelle, USEPA
Mark Gibson, ICF International
Patricia Harrigan, USEPA
Peggy Himes, Great Lakes Environmental Center
Rick Hoffmann, USEPA
Audrey Ichida, ICF International
Beth Leamond, USEPA
Patrick McCool, Great Lakes Environmental Center
Charles Noss, USEPA
Kevin Oshima, USEPA
John Ravenscroft, USEPA
Cynthia Roberts, USEPA
Grace Robiou, USEPA
Stephen Schaub, USEPA
Timothy Wade, USEPA
John Wathen, USEPA
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U.S. Environmental Protection Agency Experts Scientific Workshop
EXECUTIVE SUMMARY
The Experts Scientific Workshop on Critical Research and Science Needs for the Development of
New or Revised Recreational Water Quality Criteria took place at the Airlie Center in
Warrenton, Virginia, from March 26 to March 30, 2007. Forty-three U.S. and international
experts from academia, numerous states, public interest groups, U.S. Environmental Protection
Agency (EPA or the Agency), and other federal agencies, met to discuss the state of the science
on recreational water quality research and implementation issues.
The purpose of the workshop was for EPA to obtain input from individual members of the broad
scientific and technical community on the "critical path" research and related science needs for
developing scientifically defensible new or revised Clean Water Act (CWA) Section 304(a)
recreational ambient water quality criteria (AWQC) in the near-term. Near-term needs were
defined as those specific research and science activities that could be accomplished over the next
2 to 3 years so that results would be available to EPA in time to support development of new or
revised criteria. EPA would publish the new or revised criteria in roughly 5 years (2012).
Experts were assigned to one of seven workgroups to discuss the following seven topics essential
for EPA's development of new or revised criteria: (1) approaches to criteria development;
(2) pathogens, pathogen indicators, and indicators of fecal contamination; (3) methods
development, (4) comparing risks (to humans) from different sources; (5) "acceptable risk";
(6) modeling applications for criteria development and implementation; and (7) implementation
realities. The workshop proceedings dedicate a chapter to each of these seven topics.
Drafts of the seven chapters of the report were written by the experts at the workshop.
Subsequently, the chairs of the respective groups worked with EPA to finalize each chapter and
prepare this Executive Summary. Because the workshop's purpose was to obtain individual
input from each expert, the report is necessarily a summary of individual views. Thus,
commonalities and differences in expert opinion are acknowledged throughout the workshop
proceeding. During their deliberations, experts were asked to consider the following four main
applications and implementation issues associated with AWQC for recreational waters: (1)
listing of impaired waters under CWA §303(d); (2) total maximum daily load (TMDL)
calculations for impaired waters; (3) National Pollutant Discharge Elimination System (NPDES)
permits; and (4) recreational water monitoring and notification.
Because of the diverse nature of watersheds throughout the United States, there was general
agreement among experts that criteria that have flexibility are desirable. A common statement
from a number of workshop participants was that a "one size fits all" criterion is inadequate for
public health protection and the compliance applications under the CWA. Workshop
participants agreed that EPA should develop implementation guidance, including monitoring
protocols, concurrently with development of new or revised §304(a) AWQC, and that the criteria
and implementation guidance should be released simultaneously. This would facilitate
acceptance and adoption by States, Tribes, and Territories.
Various workshop participants suggested areas for EPA to improve lines of communication,
including with state and local governments and the public, by means of clear implementation
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guidance and timely risk communication and education activities. Experts also urged EPA to
communicate with other researchers who are planning to conduct relevant studies in the near
term; importantly, researchers who plan to conduct epidemiological studies of swimmers and
adverse health outcomes during the summers of 2007 and 2008 to determine if any of the
methods being used are appropriate for inclusion in EPA's planned summer 2007 studies.
Whether a particular method or tool (e.g., indicator type, quantification assay, use of watershed
and/or predictive models) is appropriate for addition to EPA's planned epidemiological studies
could be judged based on whether that indicator or method is important for one or more of the
four high priority research paths discussed below.
Summary of Critical Path Research
The workshop participants identified the following critical path research areas as high priority:
(1) human health impacts from different sources of fecal contamination; (2) measurement issues:
climatic, geographic, and temporal variability; (3) determining risk level and subpopulations of
concern; and (4) indicators and methods for measuring fecal contamination.
Human Health Impacts from Different Sources of Fecal Contamination
There was broad support among the workshop participants for conducting research and including
in the new or revised criteria provisions that account for differences in risks associated with
human versus nonhuman sources of fecal contamination, and point versus non-point sources
regardless of the framework ultimately proposed for the criteria. The absolute risk levels and the
magnitude of differences between animal and human waste associated risks are not well
characterized and may vary greatly geographically and temporally. Point sources and non-point
sources of fecal contamination also differ in risk and those differences are not well characterized.
Workshop participants suggested enhancements to epidemiological studies, quantitative
microbial risk assessment (QMRA), development of quantitative sanitary investigations, and
models to aid in sanitary investigations to help characterize risks.
Epidemiological studies are the preferred approach to define and quantify human health risks
from exposure to pathogens in recreational waters. Two principal study designs have been used
in previous studies of recreational watersrandomized control trials and prospective
observational cohort studies. Epidemiological studies have historically been used to assess
human health risks at beaches impacted by point sources of fecal contamination. However, the
need for additional epidemiological studies, especially at non-point source impacted beaches, is
viewed as essential to better define risk and guide future criteria development. In future
epidemiological studies, consideration should be given to enhanced study designs as well as use
of both study designs simultaneously.
QMRA can be used to rank the relative risks of different exposure scenarios, such as recreational
sites impacted by animal versus human fecal wastes, where no direct epidemiological
information is available. QMRA can also supplement existing epidemiological data, such as has
been done in a number of specific case studies in the United States and in other countries.
QMRA has the ability to consider infectivity of specific pathogens from a variety of fecal
sources and their fate and transport in waterbodies to estimate risk.
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Quantitative sanitary investigations for watershed characterization could be used to classify
water quality based on relative risk, with waters that are more likely to be impacted by human
waste being assigned a higher risk. Some methods for watershed characterization include the
following: methods for sanitary investigations, methods for fecal source identification, and
modeling to determine which watershed characteristics are related to risk of illness. Quantitative
sanitary investigations can address multiple concerns regarding the applicability of criteria,
including the impact of different sources of fecal contamination. The details of how quantitative
sanitary investigations can be designed and implemented on a national level have yet to be
determined and were not substantively addressed by the workshop participants; in part because
the process by which the details would be determined is likely to be lengthy and iterative, though
the details will be important for implementation.
Related Key Near-term Science and Research Needs:
[bracketed numbers correspond to the report chapters in EPA 823-R-07-006]:
Develop methods to quantify the difference in risk to human health from human
versus animal fecal material in recreational waters. [1, 4, 7]
o Conduct epidemiological studies at locations influenced by different types
of animals but that are not influenced by treated sewage (wastewater)
effluent or other human fecal sources. [2]
o Identify data gaps and collect data that are important for conducting QMRA
studies for estimating health risks from different sources of fecal
contamination (e.g., humans, domesticated animals, birds, point, non-point),
particularly when epidemiological data are not available. [4]
o Conduct QMRA studies to estimate the risk of low probability/high impact
illnesses from human exposure to animal waste in recreational waters.
(Animals can harbor many bacterial and protozoan pathogens that pose a
human health hazard and some of these pathogens, such as
enterohemorrhagic E. coli, can cause serious, life-threatening illness in
humans.) [4, 5]
Determine potential exposure levels and the associated health risks to
intermittent microbial pollution discharges, combined sewer overflows (CSOs),
urban runoff, and concentrated animal feeding operations (CAFOs). One aspect
of exposure includes whether swimmers are likely to be in the water during
these events, and if so, collect appropriate data (e.g., for complementary QMRA
studies). [7]
Develop protocols for using simple, heuristic, statistical models that correlate
watershed activities (presence of sewage treatment plant effluents, agricultural
activities, domesticated animals) and attributes (slope, soil type, climate, soil
moisture) to the susceptibility of a waterbody to exceed new or revised criteria
levels. [6]
Develop quantitative rather than qualitative sanitary investigation tools. A
tiered assessment of the watershed, starting with traditional fecal indicators
(conservative measures) and progressing to select a suite of indicators that
provide source specificity and load information, was suggested as one possible
approach. [1, 2, 7]
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Develop indicators and associated methods for differentiating between human
and animal fecal contamination. These methods could be part of a second or
third tier of steps in evaluating a watershed, regardless of what criteria approach
is selected. [2, 3]
Measurement Issues: Climatic, Geographic, and Temporal Variability
There was broad support among the workshop participants for conducting research and including
in the new or revised criteria provisions that account for differences in climatic regions and
geographic areas. Workshop participants were in agreement that the current state of the science
calls for the new or revised criteria to be based on indicators of fecal contamination. Experts
also agreed that enterococci and E. coli are probably not appropriate indicators in all climatic
regions (e.g., in tropical and subtropical climates) and geographic areas. Appropriate indicators
that correlate with recreator illness rates in tropical and subtropical climates are needed. New or
revised criteria need to be applicable in areas where currently accepted indicators of fecal
contamination, such as enterococci, may not be strongly correlated with observed excess illness
rates. The workshop participants felt that there is no scientific rationale to support different risk
level targets between geographic areas (i.e., freshwater and marine water) or between climatic
regions (tropical, subtropical, temperate).
Workshop participants agreed that the spatial and temporal variability evident in indicator data
sets, as well as the delay in obtaining monitoring results using conventional culture-based
methods, rendered the single sample standard impractical for routine water quality notification
purposes. Simple statistical models that do not necessarily require an understanding of processes
and mechanisms have the potential to be incorporated into the new criteria, particularly for beach
monitoring and water quality notification purposes. These models relate water quality to
environmental factors like wind speed, prior rainfall, and tide level. Models have been
demonstrated to serve as valuable tools for making closure or advisory decisions while managers
wait for laboratory results, thereby providing for improved public health protection for
swimmers as compared to relying on bacterial indicator monitoring alone. Also, once a model is
site-validated with a sufficient baseline of monitoring, further monitoring could be reduced and
targeted to instances where the model predicts exceedences of the criteria. The Modeling
workgroup members felt that due to time-lag notification errors and temporal variation known to
exist in indicator data series, day-to-day water quality notifications should not be issued using a
single sample standard in conjunction with a microbial assay that takes longer than a few hours.
Related Key Near-term Science and Research Needs:
Identify and develop indicators and corresponding methods that are appropriate
for use in tropical and subtropical recreational waters. Conduct epidemiological
studies to link those indicators with illness at tropical and subtropical locations.
[1,2,4,5]
Increase the diversity of climatic regions and geographic areas where
epidemiological studies are conducted. Also include different types of
recreational waters, such as flowing (inland) waters. [3, 7]
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Gain better understanding of temporal and spatial variability in environmental
sampling using culture-based and non culture-based methods and the
implications for their use in representing water quality. [2, 4]
Conduct research to better understand the human health significance of
regrowth and persistence of indicator bacteria in nutrient enriched surface
waters and sand/sediments and how those impact water quality determinations.
[5]
Ensure that QMRA studies conducted for estimating health risks from
swimming in recreational waters include parameters and assumptions that are
applicable for temperate, subtropical, and tropical climates. [4, 5]
Determine if data are sufficient to conduct QMRA studies for evaluating health
risks from flowing waters and collect data if possible and necessary. [7]
Develop, test, and validate water quality models for different water types with a
wide range of fecal sources and locations to improve notification accuracy. [6]
Determining Risk Level and Subpopulations of Concern
Workshop participants felt that (1) risks to children should be considered as the basis for
determining risk level associated with new or revised criteria, and (2) timely risk communication
and education of the public are critical for future acceptance of new or revised criteria. Social
sciences research is needed to inform risk communication strategies and to examine what the
public considers to be an "acceptable" level of risk for swimming-related illnesses. However,
the Acceptable Risk workgroup members agreed that the term "acceptable risk" is flawed and
should be avoided during the process of developing new or revised recreational AWQC.
Workshop participants felt that the risks to children should be better characterized and that a
better understanding of risks to children may help inform policy decisions regarding selection of
the risk level that will be associated with new or revised criteria. Epidemiological data indicate
that children can have a higher risk of illness than adults from swimming in fecal contaminated
recreational waters. Two factors contributing to this difference are (1) increased exposure from
ingestion of higher volumes of water, and (2) greater susceptibility due to immunological
differences compared to healthy adults. Note, workshop participants agreed that criteria should
not be established based on the susceptibility of immunocompromised individuals; rather,
targeted risk communication and public health messages could be used to advise these
individuals that they are at increased risk of illness and are advised not to swim.
Workshop participants emphasized that clear and transparent communication with all
stakeholders is important for the process of developing and implementing new or revised criteria.
A tiered communication plan may be an effective approach for better informing the public about
the criteria and how to interpret beach advisories and closings. Depending on the individual's
level of interest or need, the information could be basic (e.g., a sign at a beach) or more detailed
(e.g., pamphlets, websites). Workshop participants felt that EPA has a role in assisting State and
local officials in developing risk communication strategies.
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Related Key Near-term Science and Research Needs:
Review existing recreational water-related epidemiological studies to evaluate
risks to children. [1, 5]
Include the ability to evaluate specific risks to children when developing new
epidemiological studies. [1, 4, 5]
Include some element of assessing acceptability of risk in the upcoming
epidemiological studies, such as adding a sociological component. [5]
Initiate studies to assess how impacted groups understand and perceive risks
associated with recreational water use and what level of voluntary risk would be
acceptable. [5]
Indicators and Methods for Measuring Fecal Contamination
Workshop participants felt that new or revised recreational AWQC should be based on fecal
indicators. The level of occurrence and the types of pathogens in ambient waters vary greatly
both temporally and spatially. Some pathogens are only present in very small concentrations, yet
may present a public health risk. Because of these factors, methods to detect and quantify
specific pathogens in ambient waters are not sufficiently developed at present to be practical for
use in the near-term timeframe. Therefore, using suites of pathogens as the basis for new or
revised criteria was not favored among workshop participants as a first "line of defense."
However, pathogen monitoring may be useful as a subsequent tier for microbial water quality
evaluation. For longer term research needs, further development of pathogen detection methods
may result in a more important role.
There was broad expert support for new and/or improved methods for enumeration of fecal
contamination and specific pathogens; however, methods need to be evaluated in the context of
how they are going to be used for specific CWA applications. The workshop participants felt
that rapid methods are needed in some but not all water quality management situations.
Future epidemiological study design efforts should integrate sanitary investigation and water
quality modeling and incorporate characterization of the source of fecal contamination, including
measurement of pathogens and indicators. The latter includes identifying the etiological agents
in the source of fecal contamination and that cause illness in the subjects enrolled in the
epidemiological studies.
Many of the enhancements of methods and tools discussed throughout these proceedings are
likely to take longer than 2 to 3 years. Therefore, the further development of these methods and
tools should be proactively pursued to facilitate future enhancements (beyond 2012). In
situations where method and tool development proceed rapidly, then those methods and tools
would become candidates for integration into new or revised criteria in the next 5 years.
Related Science and Research Needs:
Evaluate and validate performance characteristics of methods that are linked to
new or revised criteria and ensure that those methods are developed into official
EPA Methods. [1,2,3]
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Develop and demonstrate the robustness of new methods for existing indicators
(e.g., new ways of quantifying enterococci). [3]
Develop new methods for new indicators, including but not limited to
Clostridium perfringens, adenoviruses, coliphages, and Bacteroides, to either
replace or augment the current bacterial indicators. [3, 4]
Develop methods for enumeration of pathogens and indicators in wastewater.
[1,3]
Develop methods for source identification to support watershed characterization
activities. [3]
Develop methods related to specific pathogens and fecal source identification
for use in a second tier of tests to provide for a more refined assessment of risk
of human illness. [1,3]
Conduct fate and transport studies to determine relationships between current
and new fecal indicators, index pathogens, and priority pathogens in treated
effluents and in recreational water to better inform the applicability of those
indicators and pathogens for specific CWA criteria uses. [2, 4, 7]
Summary
EPA would like to thank the workgroup chairs and other experts for their valuable contributions
to the workshop deliberations, proceedings, and this Executive Summary, and on the state of the
science of recreational water quality research and implementation issues. EPA intends to use
these reports as it develops a critical path science plan that will help guide Agency research
activities over the next 2 to 3 years in support of the development of new or revised recreational
AWQC. These research activities could be a combination of Agency-sponsored studies,
collaborative arrangements with external investigators and groups, or coordination of projects
with external investigators to help supplement Agency efforts.
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