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Recreational Water Quality
Criteria
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14 Disclaimer
15 This information is distributed solely for the purpose of obtaining scientific views on the
16 content of this document. It does not represent and should not be construed to represent
17 any final agency determination or policy.
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21 Disclaimer i
22 Appendices iii
23 Acronyms v
24 1.0 Executive Summary 1
25 1.1 Contents of this Document 1
26 1.2 EPA's Recommended §304(a) Water Quality Criteria 5
27 2.0 Applicability and Scope of the 2012 RWQC 6
28 3.0 Science and Policy Underlying the 2012 RWQC 10
29 3.1 Indicators of Fecal Contamination 10
30 3.1.1 Enumeration Methods in RWQC 11
31 3.2 Linking Water Quality and Health 13
32 3.2.1 Historical Perspectives in Criteria Development 13
33 3.2.2 Human Health Endpoint 14
34 3.2.3 Relationship Between Water Quality and Illness 16
35 3.2.4 Establishing a Comparable Illness Rate for Defining Culture and qPCR
36 Thresholds 22
37 3.3 Scope of Protected Population 29
38 3.4WaterbodyType 31
39 3.5 Sources of Fecal Contamination 34
40 3.6 Expression of Criteria 38
41 3.6.1 Use of the STV for Beach Notification 40
42 3.6.2 Criteria Magnitude, Duration, and Frequency for other CWA Purposes 40
43 3.6.3 Practical Considerations for Applying the Criteria 42
44 4.0 Recreational Water Quality Criteria 45
45 5.0 Tools to Support States and Tribes in Managing Recreational Waters and for
46 Considering Alternate Water Quality Criteria 47
47 5.1 Tools for Assessing and Managing Recreational Waters 47
48 5.1.1 Sanitary Survey 48
49 5.1.2 Predictive Models 48
50 5.2 Tools for Use in Developing Alternative RWQC 50
51 5.2.1 Epidemiological Studies 51
52 5.2.2 Quantitative Microbial Risk Assessment and Sanitary Characterization 52
53 5.2.3 Developing Alternative Criteria Based on Novel Indicators or New
54 Analytical Methods, without Site-Specific Epidemiological Studies 55
55 References 57
56
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57
58 Appendices
59 APPENDIX A. Indicators and Enumeration Methods
60 Appendix A.I: Results of the Single-Laboratory Validation of EPA Method A for
61 Enterococci and Method B for Bacteroidales in Waters by TaqMan® Quantitative
62 Polymerase Chain Reaction (qPCR) Assay, U.S. EPA, 2010.
63 Appendix A.2: Evaluation of Multiple Indicator Combinations to Develop Quantifiable
64 Relationships, U.S. EPA 2010, EPA 822-R-10-004.
65 Appendix A.3: A Study of the Various Parameters that Affect the Performance of the
66 New Rapid U.S. Environmental Protection Agency Quantitative Polymerase Chain
67 Reaction (qPCR) Method for Enterococcus Detection and Comparison with Other
68 Methods and Pathogens in Treated Wastewater Mixed with Ambient Water, U.S. EPA
69 2010, EPA 600-R-10-149.
70 Appendix A.4: Effects of Holding Time, Storage, and the Preservation of Samples on
71 Sample Integrity for the Detection of Fecal Indicator Bacteria by Quantitative
72 Polymerase Chain Reaction, U.S. EPA 2010, EPA 600-R-10-150.
73 Appendix A.5: Evaluation of the Suitability of Individual Combinations of Indicators
74 and Methods for Different Clean Water Act Programs, U.S. EPA 2010, EPA 823-R-10-
75 004.
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77 APPENDIX B. Linking Water Quality and Health
78 Appendix B.I: Critical Path Science Plan: For the Development of New or Revised
79 Recreational Water Quality Criteria, U.S. EPA, 2007.
80 Appendix B.2: Comparison and Evaluation of Epidemiological Study Designs of Health
81 Effects Associated with Recreational Water Use, U.S. EPA 2010.
82 Appendix B.3: Report on 2009 National Epidemiologic and Environmental Assessment
83 of Recreational Water Epidemiology Studies (NEEAR 2010 - Surfside & Boqueron).
84 U.S. EPA 2010, EPA 600-R-10-168.
85 Appendix B.4: Translation of 1986 Criteria Risk to Equivalent Risk Levels for Use with
86 New Health Data Developed Using Rapid Methods for Measuring Water Quality, U.S.
87 EPA 2011.
88 Appendix B.5: Comparison of NEEAR culturable water quality and health effects to
89 EPA's epidemiology studies from the 1980s : MEMO - NEEAR culture compared to
90 1980s data.
91 Appendix B.6: Report on the Expert Scientific Workshop on Critical Research and
92 Science Needs for the Development of Recreational Water Quality Criteria for Inland
93 Waters, WERF, PATH4W09.
94 Appendix B.7: MEMO - Analysis of NEEAR culture data: combining marine and fresh
95 waters.
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97 APPENDIX C. Sources of Fecal Contamination
98 Appendix C.I: Review of Published Studies to Characterize Relative Risks from
99 Different Sources of Fecal Contamination in Recreational Water, U.S. EPA 2009, EPA
100 822-R-09-001.
101 Appendix C.2: Review of Zoonotic Pathogens in Ambient Waters, U.S. EPA 2009, EPA
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102 822-R-09-002.
103 Appendix C.3: Quantitative Microbial Risk Assessment to Estimate Illness in Fresh
104 water Impacted by Agricultural Animal Sources of Fecal Contamination, U.S. EPA 2010,
105 EPA 822-R-10-005.
106 Appendix C.4: Assessment of the Applicability of Existing Epidemiology Data to Inland
107 Waters. EPA 823-Rl-0002.
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109 APPENDIX D. Supplemental Tools
110 Appendix D.I: Predictive Tools for Beach Notification Volume I: Review and Technical
111 Protocol, U.S. EPA2010, EPA 823-R-10-003.
112 Appendix D.2: Predictive Modeling at Beaches Volume II: Predictive Tools for Beach
113 Notification, U.S. EPA 2010, EPA 600-R-10-176.
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IV
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115 Acronyms
BEACH Beaches Environmental Assessment and Coastal Health Act of 2000
BMP best management practices
CCE calibrator cell equivalent
CDC U.S. Centers for Disease Control and Prevention
cfu colony forming units
CWA Clean Water Act
DNA deoxyribonucleic acid
E. coli Escherichia coll
EPA U.S. Environmental Protection Agency
E.U. European Union
FC fecal coliforms
FIB fecal indicator bacteria, which includes total coliforms, fecal
coliforms, E. coli or Enterococcus
FS fecal streptococci
GI gastrointestinal
GM geometric mean
HCGI highly credible gastrointestinal illness
MF membrane filtration
mL milliliters
MPN most probable number
NEEAR National Epidemiological and Environmental Assessment of
Recreational Water
NGI NEEAR-GI
NOAEL no observable adverse effect level
NFS non-point source pollution
NPDES National Pollutant Discharge Elimination System
NTAC National Technical Advisory Committee
PC prospective cohort
POTW publicly owned treatment works
QMRA quantitative microbial risk assessment
qPCR quantitative polymerase chain reaction
RCT randomized control trial
RWQC recreational water quality criteria
SCCWRP Southern California Coastal Water Research Proj ect
SPC sample processing control
SSM single sample maximum
States states, tribes, and territories
STV statistical threshold value
TC total coliform
TMDL total maximum daily load
TSM technical support materials
U.K. United Kingdom
U.S. United States
USDA U.S. Department of Agriculture
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U.S. EPA U.S. Environmental Protection Agency
U.S. PHS U.S. Public Health Service
UV ultraviolet (light)
WERF Water Environment Research Foundation
WHO World Health Organization (United Nations)
WQBEL water quality-based effluent limits
WQC water quality criteria
WQS water quality standard
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1.0 Executive Summary
The Clean Water Act (CWA), as amended by
the Beaches Environmental Assessment and
Coastal Health (BEACH) Act in 2000, requires
the U.S. Environmental Protection Agency
(EPA) under §104(v) and §304(a)(9) to
conduct studies associated with pathogens
and human health and to publish new or
revised criteria for pathogens and pathogen
indicators based on those studies. This
document was prepared following an extensive
review of the available scientific literature and
evaluation of new information developed in
response to §104(v). This document provides
EPA's recommended CWA §304(a)
Recreational Water Quality Criteria (RWQC)
for States, lays out the science related to the
2012 RWQC, how these scientific findings
were used during the development of the 2012
RWQC, and the water quality methods
associated with the 2012 RWQC.
1.1 Contents of this Document
Section 1 provides an executive summary and
introductory information regarding the history
of water quality criteria (WQC) and the CWA.
Section 2 provides an overview of the most
recent scientific findings used to support the
criteria and explains the scope of the 2012 RWQC. The studies and projects EPA
conducted as part of the 2012 RWQC development are described in the Critical Path
Science Plan and other documents (see Appendix B). The projects align into these major
categories: epidemiological studies, quantitative microbial risk assessment (QMRA), site
characterization studies, indicators/methods development and validation studies,
modeling, level of public health protection, and literature reviews. EPA also considered
relevant studies conducted by independent researchers.
Section 3 describes the scientific aspects that were considered during the development of
the 2012 RWQC. These include indicators of fecal contamination and enumeration
methods, linking water quality and health, scope of protected populations, types of
waterbodies, sources of fecal contamination, and the expression of the 2012 RWQC.
The 2012 RWQC recommendations indicators for fresh water are the bacteria enterococci
and Escherichia coll (E. coll) and for marine water are enterococci. Section 3.1 explains
What is new in the 2012 RWQC compared
to the 1986 Criteria?
1. EPA has developed and validated a qPCR
method as a rapid analytical technique for the
detection of enterococci in recreational water.
The method can be used to develop site-
specific criteria for beach monitoring.
2. EPA is introducing a new term, Statistical
Threshold Value (STV), as a clarification and
replacement for the term single sample
maximum (SSM). In addition there are no
longer recommendations for different use
intensities.
3. EPA is providing information on tools for
assessing and managing recreational waters,
such as predictive modeling and sanitary
surveys.
4. EPA is providing information on tools for
developing alternative RWQC on a site-
specific basis. These tools include the
continued use of epidemiological studies in
both fresh and marine waters and the
development of quantitative microbial risk
assessment (QMRA).
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163 that EPA recommends culture-based methods be used to detect the presence of both
164 indicators and quantitative polymerase chain reaction (qPCR) be used on a site-specific
165 basis for enterococci enumeration for the purposes of beach monitoring. Because of the
166 limited experience with this method, EPA recommends that States evaluate qPCR
167 performance prior to developing new or revised standards based on this qPCR method.
168 EPA will provide separate guidance on how to evaluate qPCR performance.
169
170 Section 3.2.1 provides a historical overview of how WQC have changed throughout the
171 past century. Scientific advancements in microbiological, statistical, and epidemiological
172 methods have demonstrated E. coli and enterococci are better indicators of health than the
173 previous indicators, total coliforms (TC) and fecal coliforms (FC).
174
175 Section 3.2.2 discusses the various human health endpoints that EPA and others have
176 examined in epidemiological studies. Additionally, two illness definitions are discussed.
177 EPA's 1986 criteria correspond to a level of water quality that is associated with an
178 estimated illness rate recommendations expressed in terms of the number of highly
179 credible gastrointestinal illnesses (HCGI) per 1,000 recreators. EPA's National
180 Epidemiological and Environmental Assessment of Recreational Water (NEEAR) studies
181 used a more encompassing definition of gastrointestinal (GI) illness, referred to as
182 NEEAR-GI (NGI). Because NGI is broader than HCGI (e.g., NGI includes diarrhea
183 without the requirement of fever), more illness cases were reported and associated with
184 aquatic recreation in the NEEAR studies.
185
186 Section 3.2.3 provides an overview of the epidemiological studies conducted by EPA as
187 part of the NEEAR studies. Seven studies were performed at temperate beaches impacted
188 by publicly owned treatment works (POTWs) discharging effluent from treated municipal
189 sewage. Three study beaches were in marine water and four were in fresh water. Studies
190 also were performed at two additional beaches: a temperate beach in Surfside, South
191 Carolina impacted by urban run-off sources, and a tropical beach in Boqueron, Puerto
192 Rico impacted by a POTW. EPA also considered epidemiological studies from other
193 research efforts.
194
195 Section 3.2.4 describes the process EPA used to establish a comparable illness rate for
196 culture and qPCR thresholds. EPA's recommended indicator density in the 2012 RWC
197 would retain the same level of water quality established by the 1986 criteria (U.S. EPA,
198 1986), as determined by culturable levels of enterococci for both marine waters and fresh
199 waters and E. coli levels for fresh water. The water quality level recommended in the
200 2012 RWQC for marine waters and fresh waters (as measured by enterococci)
201 corresponds to a mean estimate of illness ranging from approximately 6 to 8 cases of
202 HCGI per 1,000 recreators for both fresh and marine waters, based on the results from the
203 NEEAR studies and studies conducted in support of the 1986 criteria. EPA derived a
204 qPCR value for enterococci comparable to the culture-based value based on an illness
205 rate of 8 HCGI per 1,000 recreators for both fresh and marine waters, computed from the
206 combined NEEAR epidemiological regression model. The 2012 RWQC
207 recommendations correspond to the same level of water quality associated with the
208 previous 1986 criteria recommendations.
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209
210 Section 3.3 discusses subpopulations that participated in recreational activities in the
211 NEEAR studies. The sample sizes in the epidemiological data were not large enough to
212 capture potential differences for persons over 55 years of age, pregnant women, and other
213 subpopulations. Children aged 10 years and younger did show a difference from adults in
214 fresh water, but the sample size for marine water exposures was too small to draw
215 statistical conclusions for children. EPA is basing the 2012 RWQC on the general
216 population, which includes children. Because children may be more exposed and more
217 sensitive to pathogens in recreational waters, it is imperative that effective risk
218 communication outreach be done to mitigate their exposure to contaminated waters
219 effectively. Alerting families with children when the water quality does not meet the
220 States' applicable WQS on a given beach day, in real time, will allow for better
221 protection of children.
222
223 Section 3.4 describes EPA's review of the available information comparing coastal
224 (including Great Lakes and marine) and non-coastal (including flowing and non-flowing
225 inland) waters to evaluate whether EPA should recommend that States use the 2012
226 RWQC in developing recreational water quality standards (WQSs) in all waterbody
227 types. Based on EPA's evaluation of the body of information described in section 3.4,
228 EPA recommends the 2012 RWQC for use in both coastal and non-coastal waterbodies.
229 While some differences may exist between coastal and non-coastal waters, WQS based
230 on the recommended criteria in both waterbody types would constitute a prudent
231 approach to protect public health. Therefore, EPA's §304(a) RWQC recommendations
232 are national recommendations for all surface waters of the United States designated for
233 swimming, bathing, surfing, or similar water contact activities (referred to throughout this
234 document as "primary contact recreational use").
235
236 Section 3.5 describes EPA's evaluation of how different fecal sources may influence
237 risks to human health. EPA's research indicates that the source of contamination is
238 critical for understanding the human health risk associated with recreational waters and
239 that there is variability in the amount of human health risk in recreational waters from the
240 various fecal sources due to the wide-ranging environmental conditions that occur across
241 the United States. Human pathogens, microorganisms that could cause disease, are
242 present in animal fecal matter. Therefore, there is a level of risk from recreational
243 exposure to human pathogens in animal-impacted waters. Quantifying that risk is
244 difficult, however, and the methods necessary to distinguish between human and
245 nonhuman sources, with the appropriate level of confidence, are still under development.
246 EPA concluded that States adopting the 2012 RWQC would have WQS protective of
247 public health, regardless of the source of fecal contamination. EPA is not developing
248 separate national criteria for nonhuman sources. States interested in adopting different
249 standards to address the potential human health risk differences from different sources of
250 fecal contamination on a site-specific basis should refer to section 5 of this document for
251 suggestions on approaches.
252
253 Section 3.6 describes the statistical expression of the RWQC. As part of the 2012
254 RWQC, EPA is recommending that the criteria be expressed using two components: the
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255 geometric mean (GM) and the 75th percentile Statistical Threshold Value (STV). EPA
256 computed the STV based on the water quality variance observed during EPA's
257 epidemiological studies. The STV corresponds to the 75th percentile of an acceptable
258 water-quality distribution. Because fecal indicator bacteria (FIB; which refers to TC, FC,
259 E. coli or Enterococcus) are highly variable in environmental waters, distributional
260 estimates are more robust than single point estimates. EPA is including the STV in the
261 2012 RWQC, rather than the term "single sample maximum," to resolve previous
262 inconsistencies in implementation. In addition, the 2012 RWQC are no longer
263 recommending multiple "use intensity" values, in an effort to increase national
264 consistency across bodies of water and ensure equivalent public health protection in all
265 waters.
266
267 Section 4 presents EPA's recommended magnitude, duration, and frequency for E. coli
268 and enterococci as measured by the culture method.. The designated use of primary
269 contact recreation would be protected if the following criteria are adopted into State
270 WQSs:
271 (a) For fresh waters, a criterion that measures E. coli using EPA Method 1603, or any
272 other equivalent method that measures culturable E. coli at a GM of 126 colony
273 forming units (cfu) per 100 milliliters (mL) and an STV of 235 cfu per 100 mL; a
274 criterion for enterococci measured using EPA Method 1600 (U.S. EPA 2002b), or
275 any other equivalent method that measures culturable enterococci at a GM of 33 cfu
276 per 100 mL and an STV of 61 cfu per 100 mL; or both of the above criteria.
277
278 (b) For marine waters, a criterion that measures enterococci using EPA Method 1600,
279 or another equivalent method that measures culturable enterococci at a GM of 35 cfu
280 per 100 mL and an STV of 104 cfu per 100 mL.
281
282 For the purposes of beach monitoring, EPA is providing information to States for
283 developing a site-specific criterion that measure enterococci using EPA Enterococcus
284 qPCR Method A, at a GM of 475 calibrator cell equivalent (CCE) per 100 mL and an
285 STV of 1,000 CCE per 100 mL.
286
287 Section 5 describes the tools that can be used to assess and manage recreational waters
288 and derive site-specific criteria. The tools listed in section 5 will not only provide States
289 with additional options for revising their WQS for primary contact recreation, but will
290 also help States gain a better understanding of their surrounding watersheds. Section 5.1
291 describes sanitary surveys and provides an overview of predictive models. Section 5.2
292 provides an overview of how epidemiological studies, QMRA, and alternative fecal
293 indicator/method combinations may be used to support the development of site-specific
294 criteria. The use of alternative fecal indicators and methods may not be scientifically
295 defensible or protective of the use for all CWA purposes. All of the tools described in
296 section 5 will be further explained in technical support materials (TSM) that are being
297 developed by EPA.
298
299 A series of appendices is also included. Appendix A provides additional information on
300 indicators and enumeration methods, Appendix B describes data and information used to
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301 evaluate the linking of water quality and health, Appendix C contains information on
302 sources of fecal contamination, and Appendix D provides additional information on
303 supplemental tools.
304
305 1.2 EPA's Recommended §304(a) Water Quality Criteria
306
307 An important goal of the CWA is to protect and restore waters for swimming. Section
308 304(a) of the CWA directs EPA to publish and, from time to time, to revise the WQC to
309 accurately reflect the latest scientific knowledge on the identifiable effects on health and
310 welfare that might be expected from the presence of pollutants in any body of water,
311 including groundwater. These recommendations are referred to as §304(a) criteria. Under
312 §304(a)(9) of the CWA, EPA is required to publish WQC for pathogens and pathogen
313 indicators based on the results of the studies conducted under §104(v) for the purpose of
314 protecting human health in coastal recreation waters.
315
316 The 2012 RWQC recommendations are based on data and scientific conclusions on the
317 relationship between FIB density and GI illness and do not reflect the economic impacts
318 or technological feasibility of meeting the criteria. These criteria recommendations may
319 be used by the States to establish WQS, and if adopted in State WQS, will ultimately
320 provide a basis for controlling the discharge or release of pollutants and assessing water
321 bodies. Additionally, the criteria also provide guidance to EPA when promulgating WQS
322 for States under CWA §303(c), when such actions are necessary. Monitoring and
323 sampling strategies are not included in the 2012 RWQC. The criteria recommendations
324 do not address pollutants in sand, except to the degree that sand may serve as a source of
325 FIB in recreational waters.
326
327 When adopting new or revised WQSs, the States must adopt criteria that are scientifically
328 defensible and protective of the designated uses of the bodies of water. EPA's regulations
329 stated in 40 CFR §131.11(b)(l) provide that "In establishing criteria, States should (1)
330 Establish numerical values based on (i) 304(a) Guidance; or (ii) 304(a) Guidance
331 modified to reflect site-specific conditions; or (iii) Other scientifically defensible
332 methods." EPA's 2012 RWQC recommendations describe the desired ambient water
333 quality conditions to support the designated use of primary contact recreation. WQS are
334 used in various CWA programs to identify and address sources of pollution, with the
335 ultimate goal of attaining standards. These CWA programs include National Pollutant
336 Discharge Elimination System (NPDES) permitting, waterbody assessments, and the
337 development of total maximum daily loads (TMDLs). In addition, the BEACH Act
338 requires States with coastal waters to use WQS in beach monitoring and water quality
339 notification programs funded by EPA grants.
340
341 EPA's current recommended criteria for protecting people who use recreational waters
342 are based on fecal indicators of bacterial contamination. In the 1960s, the U.S. Public
343 Health Service (U.S. PHS) recommended using fecal coliform as indicator bacteria and
344 EPA revised the recommendation in 1976 (U.S. EPA, 1976). In the late 1970s and early
345 1980s, EPA conducted epidemiological studies that evaluated the use of several
346 organisms as possible indicators, including FC, E. coli, and enterococci (Cabelli et al.,
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347 1983; Dufour, 1984). These studies showed that enterococci are good predictors of GI
348 illnesses in fresh and marine recreational waters and E. coli is a good predictor of GI
349 illnesses in fresh waters. As a result, EPA published EPA 's Ambient Water Quality
350 Criteria for Bacteria - 1986 (hereafter referred to as "the 1986 criteria") for determining
351 contamination levels in recreational waters. This document recommends the use of E. coli
352 for fresh recreational waters (the criteria recommend a GM of 126 cfu per 100 mL) and
353 enterococci for fresh and marine recreational waters (the criteria recommends a GM of 33
354 cfu per 100 mL in fresh water and 35 cfu per 100 mL in marine water) (U.S. EPA, 1986).
355 The 1986 recommendations replaced the U.S. PHS previously recommended FC criteria
356 of 200 cfu per 100 mL (US EPA, 1976). In 2004, EPA promulgated the!986 criteria as
357 the WQSs for coastal recreational waters in the 21 States that had not yet adopted
358 standards as protective of human health as EPA's 1986 criteria recommendations (U.S.
359 EPA, 2004). Since the promulgation of the BEACH Act Rule, six States have adopted
360 their own standards that are as protective of human health as EPA's 1986 criteria
361 recommendations and therefore, they are no longer covered by the Federal standards.
362
363 Like past EPA recommendations for the protection of people using bodies of water for
364 recreational uses, such as swimming, bathing, surfing, or similar water-contact activities,
365 these criteria are based on an indicator of fecal contamination, which is a pathogen
366 indicator because pathogens frequently occur with fecal contamination. A pathogen
367 indicator, as defined in §502(23) of the CWA and amended by the BEACH Act, is
368 defined as follows: "a substance that indicates the potential for human infectious
369 disease." Most strains of E. coli and enterococci do not cause human illness (that is, they
370 are not human pathogens); rather, they indicate the presence of fecal contamination. The
371 basis for recommending criteria that use bacterial indicators of fecal contamination is that
372 pathogens often co-occur with indicators of fecal contamination.
373
374 2.0 Applicability and Scope of the 2012 RWQC
375
376 EPA's 2012 RWQC recommendations supersede EPA's previous criteria
377 recommendations to protect primary contact recreation, Ambient Water Quality Criteria
378 for Bacteria - 1986 (referred to as the "1986 criteria"). These recommendations are for
379 all waters in the U.S. including coastal, estuarine, Great Lakes, and inland waters that are
380 designed for swimming, bathing, surfing, or similar water-contact activities ("primary
381 contact recreation"). When swimming, bathing, surfing, water skiing, tubing, skin diving,
382 water play by children, or engaging in similar water-contact activities, immersion and
383 ingestion are likely and there is a high degree of bodily contact with the water.
384
385 Since EPA last issued recommended RWQC in 1986, scientific advances have been made
386 in the areas of epidemiology, molecular biology, microbiology, QMRA, and methods of
387 analytical assessment. Adding these new scientific and technical advances in the
388 development of the 2012 RWQC strengthens the scientific foundation of EPA's criteria
389 recommendations to protect the designated use of primary contact recreation.
390
391 In accordance with § 104(v) of the CWA, as amended by the BEACH Act, EPA
392 developed and implemented a research plan to ensure that state-of-the-art science would
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393 be available to support the development of the 2012 RWQC recommendations. To
394 facilitate the identification of research required to develop the 2012 RWQC, EPA held a
395 5-day scientific workshop in 2007 to obtain a broad range of external scientific input.
396 Forty-three U.S. and international experts provided input on near-term research
397 requirements that would be needed in the next 2-3 years to further develop the scientific
398 foundation of new 2012 RWQC and implementation guidance. The report from this
399 workshop, Report of the Experts Scientific Workshop on Critical Research Needs for the
400 Development of New or Revised Recreational Water Quality Criteria (U.S. EPA, 2007a),
401 included chapters from the seven breakout groups: (1) approaches to criteria
402 development, (2) pathogens, pathogen indicators, and indicators of fecal contamination,
403 (3) methods development, (4) comparing the risks of different contamination sources to
404 humans, (5) acceptable risk, (6) modeling applications for criteria development and
405 implementation, and (7) implementation realities.
406
407 The report from the Experts Scientific Workshop provided a core part of the information
408 EPA used to develop the Critical Path Science Plan for the Development of New or
409 Revised Recreational Water Quality Criteria (U. S. EPA, 2007b). The Critical Path
410 Science Plan, which was peer reviewed, includes 32 projects that EPA completed for the
411 development of the 2012 RWQC. All projects included in the Critical Path Science Plan,
412 and any additional projects, were completed and considered during the process of
413 developing the 2012 RWQC. These projects included epidemiological studies to provide
414 data correlating illness with indicators, site-characterization studies to facilitate QMRA,
415 indicator and methods development and validation, water quality modeling, literature
416 reviews, and additional studies to support appropriate levels of public health protection.
417 EPA also supported the Water Environment Research Foundation (WERF) workshop,
418 Experts Scientific Workshop on Critical Research and Science Needs for the
419 Development of Recreational Water Quality Criteria for Inland Waters, to consider the
420 significance of the differences between inland and coastal recreational waters (WERF,
421 2009). As summarized or included in the appendices, these projects included efforts in
422 the following areas:l
423
424 • Epidemiological Studies and QMRA
425 ° 2003-2004 Temperate Fresh water: four beach sites on the Great Lakes
426 ° 2005-2007 Temperate Marine: three beach sites: Alabama, Rhode Island,
427 Mississippi
428 ° 2009 sites: Puerto Rico (tropical), South Carolina (urban runoff)
429 ° QMRA for fresh water impacted by agricultural animals
430 ° Technical support to the Southern California Coastal Water Research
431 Project (SCCWRP) for epidemiological studies at the beaches of Doheny,
432 Avalon, and Malibu
433 • Site Characterization Studies
434 ° Development of site characterization tool for QMRA applications
1 EPA's RecreationalWater Quality Criteria website:
http://water.epa.gov/scitech/swguidance/standards/criteria/health/recreation/
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435 ° Expanded data collection at epidemiological study locations to support
436 modeling and QMRA
437 ° Site selection evaluation for Puerto Rico and South Carolina
438 epidemiological studies
439 ° Study to better understand spatial and temporal variability
440 ° Pilot sanitary survey in the Great Lakes
441 • Indicators/Methods Development and Validation Studies
442 ° Evaluate multiple indicator/method combinations to develop quantifiable
443 relationships
444 ° Study the effects of sample holding time, storage, and preservation
445 ° Performance of qPCR signal in ambient water and wastewater (fate and
446 transport)
447 ° Develop, refine, validate, and publish new ambient and wastewater
448 methods
449 ° Publish a rapid test method that has been validated by multiple
450 laboratories
451 ° Evaluate the suitability of individual combinations of indicators and
452 methods for different CWA purposes
453 ° Develop new and/or evaluate previously published source-identifying
454 assays
455 ° Evaluate genetic markers for human, bovine, chickens, and gulls
456 • Modeling
457 ° Pilot test Virtual Beach Model Builder
458 ° Refine and validate existing models for fresh water beaches
459 ° Refine and validate other existing models for marine beaches
460 ° Develop technical protocol for site-specific application of predictive
461 models
462 • Appropriate Level of Public Health Protect!on
463 ° Evaluate 1986 recommendations for culturable E. coli and enterococci
464 compared to data collected in EPA studies and non-EPA studies
465 ° Evaluate applicability of EPA Great Lakes epidemiological data to inland
466 waters
467 ° Evaluate available children's health data
468 • Literature Reviews
469 ° State-of-the-science reviews of published studies to characterize relative
470 risk from different fecal sources
471 ° State-of-the-science review on occurrence and cross-infectivity of specific
472 pathogens associated with animals
473 ° Comparison and evaluation of epidemiological study designs of health
474 effects associated with recreational water use
475
476 EPA epidemiological studies were conducted at U.S. beaches in 2003, 2004, 2005, 2007,
477 and 2009, and as a group are referred to as the NEEAR studies. These studies enrolled
478 54,250 participants, encompassed 9 locations, and collected and analyzed numerous
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479 samples from a combination of fresh water, marine, tropical, and temperate beaches
480 (Wade et al., 2008, 2010; U.S. EPA, 2010d).
481
482 In addition to its own studies, EPA considered independent research, based on a
483 comprehensive search of the scientific literature, which was related to the development of
484 the 2012 RWQC. These studies included epidemiological studies, research on the
485 development of new and improved water quality indicators and analytical methods,
486 approaches to QMRA, water quality predictive modeling, and microbial-source tracking.
487 As of the date of the draft RWQC, EPA received data from SCCWRP, which were
488 generally consistent with the NEEAR study findings. However, because results were
489 preliminary in nature, they were not considered quantitatively. These scientific topics are
490 discussed further in section 3 of this document.
491
492
493
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494 3.0 Science and Policy Underlying the 2012 RWQC
495
496 To develop the 2012 RWQC, EPA considered indicators of fecal contamination, methods
497 for detecting and enumerating such indicators, the relationship between the occurrence of
498 FIB in the water and their human health effects, the populations to be protected by the
499 2012 RWQC, waterbody types, sources of fecal contamination, and how the 2012 RWQC
500 should be expressed in terms of the magnitude, duration, and frequency of any excursions
501 above the criteria values. For each aspect of the 2012 RWQC, the following variables are
502 discussed: background related to the 1986 criteria, new scientific findings and
503 information, and what EPA is proposing for the 2012 RWQC recommendations.
504
505 Indicators of fecal contamination and RWQC indicator organisms can be detected
506 through different methods, thus information on both the indicator organism and the
507 method of detection are important for RWQC. The important linkage between the
508 organism and the method is captured throughout this document by the use of the term
509 indicator/method to refer to the combination of both. EPA believes that addressing only
510 the organism or only the method is not adequate for deriving RWQC because the
511 organism and the detection method result in different units (see Section 3.1.1).
512
513 3.1 Indicators of Fecal Contamination
514
515 Public health agencies have long used FIB to identify potential for illness resulting from
516 the engagement in recreational activities in surface waters contaminated by fecal
517 pollution. EPA based its 1986 criteria for marine and fresh recreational waters on levels
518 of bacterial indicators of fecal contamination, specifically E. coli and enterococci for
519 fresh water and enterococci for marine water. Although generally not inherently
520 pathogenic, these particular FIB demonstrate characteristics that make them good
521 indicators of fecal contamination, and thus, indirectly indicate the potential presence of
522 fecal pathogens capable of causing GI illnesses. As such, FIB are "pathogen indicators"
523 as that term is defined by Section 502(23) -"a substance that indicates the potential for
524 human infectious diseases" - even though they are not generally thought of as "pathogen
525 indicators," as that term is typically used by the scientific community as direct indicators
526 of pathogens. EPA cannot publish criteria for "pathogens" at this time because the
527 current state of the science is not sufficient to support this effort. In addition, there are
528 numerous pathogens that cause the full range of illnesses associated with primary contact
529 recreation. Many pathogen specific methods were not finalized at the time of the fresh
530 and marine water epidemiology studies, and thus a health relationship was not
531 established. For additional information on indicators, see Appendix A.3 and A.5.
532
533 Several microorganisms that are potential indicators of fecal contamination are normally
534 present in fecal material. Not all of these indicators, however, have a clear relationship to
535 illness levels observed in epidemiological studies. Two microorganisms that have
536 consistently performed well as indicators of illness in epidemiological studies are
537 enterococci in both fresh and marine water and E. coli in fresh water (see Section 3.2.3).
538 Although EPA does not have recent epidemiological data on E. coli in fresh water, two
539 independent epidemiological studies support the utility of E. coli as an indicator as
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540 recommended in the 1986 criteria (Marion et al., 2010, Wiedenmann, 2006). A meta-
541 analysis of 27 studies also supports E. coli as an indicator in fresh water (Wade et al.,
542 2003). See section 5.2.3 for discussion of alternative indicators that EPA has not
543 specifically included in 2012 RWQC.
544
545 Some human pathogens, such as various species of Vibrio., Legionella, and the free-living
546 amoeba Naegleria, occur naturally in the environment (Cangelosi et al., 2004; Pond,
547 2005). Other aquatic microbes, such as harmful algae, cyanobacteria, diatoms, and
548 dinoflagellates, produce toxins that can cause human illnesses. These microbes were not
549 the focus of the 2012 RWQC because adverse health effects that occur in humans from
550 these microorganisms have not been associated with FIB.
551
552 3.1.1 Enumeration Methods in RWQC
553
554 FIB can be enumerated using various analytical methods including those in which the
555 organisms are grown (cultured) and those in which their deoxyribonucleic acid (DNA) is
556 amplified and quantified (qPCR). These different enumeration methods result in method-
557 specific units and values. One culture method, membrane filtration (MF), results in the
558 number of cfu that arise from bacteria captured on the filter per volume of water. One
559 colony can be produced from one or several cells (clumped cells in the environmental
560 sample). Another culture method, the defined substrate method, produces a most probable
561 number (MPN) per volume. MPN analyses estimate the number of organisms in a sample
562 using statistical probability tables, hence the "most probable number." Bacterial densities
563 are based on the combination of positive and negative test tube results that can be read
564 from an MPN table (U.S. EPA, 1978). Culture-based approaches for the enumeration of
565 FIB, such as MPN and MF, do not result in a direct count or concentration of the bacteria
566 being enumerated but rather rely on probabilities and generate results following culturing
567 of a particular microbe for 18-24 hours. Results from qPCR analysis are reported in CCE
568 units that are calculated based on the target DNA sequences from test samples relative to
569 those in calibrator samples that contain a known quantity of target organisms (Haugland
570 etal., 2005, Wade etal.,2010).2
571
572 The results from each of these enumeration techniques depend on the method used. Each
573 analytical technique focuses on different attributes of the fecal indicator and results in a
574 "signal" specific to that technique. For example, culture-based methods fundamentally
575 depend on the metabolic state (i.e., viability) of the target organisms for effective
576 enumeration. Only the culturable members of the target population are detected using
577 culture-based techniques. Alternatively, qPCR-based approaches detect specific
578 sequences of DNA that have been extracted from a water sample, and results contain
579 sequences from all members of the target population, both viable and nonviable. In the
580 context of the 2012 RWQC, the results for enterococci determined using the culture
2 Note that in some EPA NEEAR study publications, the term calibrator cell equivalents (CCEs) has been
shortened to cell equivalents (CEs). EPA considers these terms to be synonymous and in all cases calibrator
cells were used. EPA used the delta-delta comparative Ct calibration model for estimating CCE or CE in
all NEEAR studies.
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581 methods are not the same as the results for enterococci detected by qPCR methods. These
582 results are not directly interchangeable and require an explanation of each method's
583 results as they relate to the reported health effects (i.e., epidemiological relationships; see
584 section 3.2).
585
586 FIB, such as E. coli, enumerated by culture-based methods have a demonstrated
587 correlation with GI illness from exposure to ambient recreational water previously
588 (Dufour 1984; Wade et al. 2003) and more recently (Marion et al., 2010,Wiedenmann et
589 al., 2006), provide a historical association with previous water-quality data, and are
590 scientifically defensible and protective of the primary contact recreation use when used
591 for multiple CWA programs (beach monitoring and notifications, §303[d] listing,
592 permits, TMDLs). Culture-based methods have a time lag of 24 hours or more between
593 sample collection and results. This lag is less of an issue if monitoring is coupled with a
594 calibrated predictive model (see section 5.1.2).
595
596 EPA is also providing information on how to use a more recently developed qPCR
597 method as a site-specific criterion for the purposes of beach monitoring. This
598 methodology showed a statistically significant correlation with GI illness among
599 swimmers in both marine and fresh recreational waters impacted by human fecal
600 contamination (Wade et al., 2006, 2008, 2010). The technical literature demonstrates that
601 this enterococci enumeration technique can provide results more rapidly than culture-
602 based methods, with results available the same day (Griffith and Weisberg, 2011). Thus,
603 the strengths of the Enterococcus qPCR compared to the culture method include rapidity
604 and demonstration of stronger and more sensitive health relationships in the NEEAR
605 studies.
606
607 As with other methods, including culture methods, the qPCR methodology may be
608 affected by unpredictable interference from substances in different environmental
609 matrices such as surface waters. Interference is any process that results in lower
610 quantitative estimates than expected or actual values. Unlike culture methods, the EPA
611 Enter ococcus qPCR method (U.S. EPA Method A, 201 Oh) has a sample processing
612 control (SPC) assay that is performed on each sample to identify unacceptable levels of
613 interference (defined as a 3-Ct unit shift compared to corresponding control samples).
614
615 While the fresh water NEEAR studies in the Great Lakes and four temperate marine
616 beaches demonstrated minimal to no inhibition, EPA's overall testing of qPCR in
617 ambient waters has been limited. EPA anticipates that there may be situations at a given
618 location where the qPCR performance may be inconsistent with respect to sample
619 interference. Given that there is limited information on the performance of EPA's
620 Enterococcus qPCR method in inland and tropical marine waters, EPA recommends that
621 States evaluate qPCR performance with respect to sample interference prior to
622 developing new or revised standards relying on this method for the purposes of beach
623 monitoring. EPA will provide guidance on how to evaluate performance with respect to
624 sample interference at a particular site at a later date.
625
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626 3.2 Linking Water Quality and Health
627
628 This section discusses the information that EPA considered during the course of
629 evaluating the association between measures of water quality and potential human health
630 effects from exposure to fecal contamination. There are many scenarios where fecal
631 contamination can impact a waterbody, and the relationship between the presence of FIB
632 and of the pathogens that cause illness can be highly variable. The following four
633 subsections—historical perspectives in criteria development, human health endpoints,
634 water quality and illness, and derivation of recommended numerical criteria values—
635 describe the lines of evidence EPA used to support the association between the 2012
636 RWQC and human health protection. The historical perspectives subsection briefly
637 discusses previous approaches to the development of WQC in the United States. The
638 human health endpoint subsection explains how the definition of illness is important for
639 understanding the meaning of the associated 2012 RWQC illness-rate levels. The water
640 quality and illness subsection presents the results of epidemiological studies that EPA
641 considered when developing the 2012 RWQC. The derivation subsection discusses the
642 mathematical basis of the 2012 RWQC values.
643
644 3.2.1 Historical Perspectives in Criteria Development
645
646 EPA's previously recommended recreational water-quality criteria (the 1986 criteria) and
647 the 2012 RWQC are based on the association between the density of FIB and observation
648 of GI illnesses. FIB levels have long served as the surrogate measure of fecal
649 contamination and thus the presence of pathogens that are commonly associated with
650 fecal material.
651
652 In the 1960s, the U.S. PHS recommended using FC bacteria as the indicator of primary
653 contact with FIB. Studies the U.S. PHS conducted reported a detectable health effect
654 when TC density was about 2,300 per 100 mL (Stevenson, 1953). In 1968, the National
655 Technical Advisory Committee (NTAC) translated the TC level to 400 FC per 100 mL
656 based on a ratio of TC to FC, and then halved that number to 200 FC per 100 mL (U.S.
657 EPA, 1986). The NTAC criteria for recreational waters were recommended again by EPA
658 in 1976.
659
660 In the late 1970s and early 1980s, EPA conducted a series of epidemiological studies to
661 evaluate several additional organisms as possible indicators of fecal contamination,
662 including E. coli and enterococci. These epidemiological studies showed that enterococci
663 are a good predictor of GI illnesses in fresh and marine recreational waters, and E. coli is
664 a good predictor of GI illnesses in fresh waters (Cabelli et al., 1982; Cabelli, 1983;
665 Dufour, 1984).
666
667 The 1986 criteria values represent the desired ambient condition of the water body
668 necessary to protect the designated use of primary contact recreation. Those values were
669 selected in order to further carry forward the same level of water quality associated with
670 EPA's previous criteria recommendations to protect the primary contact recreation use,
671 which were for FC (US EPA, 1976). For this effort, the enterococci and E. coli criteria
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672 values from the existing FC criteria were translated using the GM values for the FIB
673 established in the previous epidemiological studies (see Text Box 1, below) (Dufour and
674 Schaub, 2007). The SSM component of the 1986 criteria was computed using the GM
675 values and corresponding observed variances in the FIB obtained from water quality
676 measurements taken during the epidemiological studies from the 1970s and 1980s. The
677 1986 criteria values resulted in different values and corresponding illness rates for marine
678 and fresh waters because the marine and fresh water epidemiological studies reported
679 different GMs for the FIB associated with the level of water quality corresponding to
680 EPA's FC criteria recommendations.
681
682
683 Text Box 1. Translation of 1960s criteria to 1986 criteria
The 1986 criteria values (A) were derived as follows
A = (B*C)/D
Where
B is the observed GM enterococci (from epidemiological studies)
C is the criterion for fecal coliform (200 cfu per 100 mL)
D is the observed GM fecal coliform (from epidemiological studies)
684
685
686 For example, using the equation in Text Box 1, the marine enterococci 1986 criterion was
687 calculated as follows:
688
689 B = 20 cfu per 100 mL (observed GM enterococci)
690 C = 200 cfu per 100 mL (old FC standard)
691 D = 115 cfu per 100 mL (observed GM fecal coliforms)
692 Therefore, A = 3 5 cfu per 100 mL.
693
694 Using the observed relationships between the FIB densities and GI illness, EPA estimated
695 in 1986 that the predicted level of illness associated with the criteria was 8 HCGI per
696 1,000 recreators in fresh water (see section 3.2.2) and 19 HCGI per 1,000 recreators in
697 marine waters (U.S. EPA, 1986).
698
699 3.2.2 Human Health Endpoint
700
701 EPA's 1986 criteria values correspond to a level of water quality associated with an
702 estimated level of illness that is expressed in terms of the number of HCGI. The HCGI
703 case definition is "any one of the following unmistakable or combinations of symptoms
704 [within 8 to 10 days of swimming]: (1) vomiting (2) diarrhea with fever or a disabling
705 condition (remained home, remained in bed or sought medical advice because of
706 symptoms), (3) stomachache or nausea accompanied by a fever."
707
708 EPA's NEEAR epidemiological studies used a different definition of GI illness, defining
709 a case of GI illness as "any of the following [within 10 to 12 days after swimming]: (a)
710 diarrhea (3 or more loose stools in a 24 hour period), (b) vomiting, (c) nausea and
711 stomachache, or (d) nausea or stomachache and impact on daily activity." This illness
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712 definition is referred to as NGI and is the definition of illness associated with the 2012
713 RWQC. For additional information, see Appendix B.
714
715 The NGI case definition was broadened in that diarrhea, stomachache, or nausea is
716 included without the occurrence of fever. Viral gastroenteritis does not always present
717 with a fever, so including GI illness without fever incorporates more types of viral
718 illnesses in this definition. Viruses are thought to be the etiologic agent responsible for
719 most GI illnesses that are contracted in recreational waters impacted by sources of human
720 fecal contamination (Cabelli, 1983; Seller et al., 2010a).
721
722 In addition, the NEEAR studies extended the number of days following the swimming
723 event in which illness may have been observed to account for pathogens with longer
724 incubation times. For example, the incubation of Cryptosporidium spp. can be up to 10
725 days, thus participants contacted after 8 days may not have developed symptoms. By
726 calling participants after 10 days, the study design allowed for illness caused by
727 pathogens associated with longer incubation periods to be included. Similar GI
728 definitions are now widely used nationally and internationally (Colford et al., 2002, 2007;
729 Payment, 1991, 1997; Sinigalliano et al., 2010; Wiedenmann et al., 2006).
730
731 Because the NGI definition is broader than HCGI, more illnesses qualify to be counted as
732 "cases" in the epidemiological studies, than if the older HCGI definition were applied.
733 Therefore, at the same level of water quality, more NGI illnesses will be observed than
734 HCGI illnesses. The relative differences in rates of GI illness between the studies (i.e.,
735 HCGI versus NGI) are directly attributable to the changes in how illness was defined and
736 not due to an actual increase in the incidence of illness among swimmers at a given level
737 of water quality.
738
739 EPA estimated how the GI illness rate associated with the two GI illness definitions can
740 be compared using the difference between (a) non-swimmer illness rates from the pre-
741 1986 epidemiological data, and the (b) non-swimmer illness rates from the NEEAR
742 studies (U.S. EPA, 201 la). The non-swimmer HCGI rate from pre-1986 epidemiological
743 studies was 14 illnesses per 1,000 non-swimmer recreators, while the non-swimmer
744 recreators NGI rate from the NEEAR studies was 63 illnesses per 1,000 non-swimmer
745 recreators. Thus an illness level of 8 HCGI per 1,000 recreators is estimated to be
746 equivalent with an illness level of 36 NGI per 1,000 recreators (estimated translation
747 factor of 4.5 NGI per HCGI). For analyses presented in section 3.2.4, the HCGI illness
748 rate metric was used, through this translation factor, in order to maintain comparability to
749 the 1986 criteria.
750
751 Of all the adverse health effects considered, the NEEAR epidemiological studies found
752 the strongest association with GI illnesses (see section 3.2.3). In addition to NGI
753 illnesses, the NEEAR epidemiological studies evaluated other health endpoints that could
754 have been caused by pathogens found in fecal matter. These included the following:
755 1. "Upper respiratory illness," which was defined as any two of the following: sore
756 throat, cough, runny nose, cold, or fever;
757 2. "Rash," which was defined as a rash or itchy skin;
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758 3. "Eye ailments," which were defined as either an eye infection or a watery eye;
759 4. "Earache," which was defined as ear pain, ear infection, or runny ears;
760 5. "Infected cut," which was defined as a cut or wound that became infected.
761
762 Results from the NEEAR studies and previous epidemiological studies indicate that
763 criteria based on protecting the public from GI illness correlated with FIB will prevent
764 most types of recreational waterborne illnesses. In general, these other illnesses occur at a
765 lower rate than GI illness (Fleisher et al., 1998; Haile et al., 1999; McBride et al. 1998;
766 Wade et al. 2008). For example, Wade et al. (2008) reported overall GI illness incidence
767 of 7.3 percent, upper respiratory infection incidence of 5.7 percent, rash incidence of 2.7
768 percent, and eye irritations and infections of 2.9 percent. Kay et al. (1994) and Fleisher et
769 al. (1998) reported 14.8 percent GI illness in swimmers and 9.7 percent in non-
770 swimmers, 4.7 percent incidence of respiratory infection in swimmers and 3 percent in
771 non-swimmers, and 4.2 percent incidence of ear ailments in swimmers and 4.8 percent
772 and non-swimmers.
773
774 Non-EPA studies in waters not impacted by POTWs found correlations between other
775 health endpoints and water quality. Sinigalliano et al. (2010) reported symptoms between
776 one set of human subjects randomly assigned to marine water exposure with intensive
777 environmental monitoring compared with other subjects who did not have exposure.
778 Their results demonstrated an increase in self-reported GI, respiratory, and skin illnesses
779 among bathers compared to non-bathers. Among the bathers, a relationship was observed
780 between increasing FIB and skin illness, where skin illness was positively related to
781 enterococci enumeration by culture methods.
782
783
784 3.2.3 Relationship Between Water Quality and Illness
785
786 The protection of the primary contact recreation use has always been the goal of bacterial
787 WQCs in the United States. For decades, epidemiological studies have been used to
788 evaluate how FIB levels are associated with health effects of primary contact recreation
789 on a quantitative basis. The 1986 criteria recommendations are supported by
790 epidemiological studies conducted by EPA in the 1970s and 1980s. In those studies, E.
791 coli and enterococci exhibited the strongest correlation to swimming-associated
792 gastroenteritis (specifically HCGI, as discussed in section 3.2.2). Because these indicators
793 correlate with illness, EPA selected E. coli as the indicator to be measured in fresh water
794 and enterococci as an indicator to be measured in both fresh water and marine water.
795 Both indicators continue to be used in epidemiological studies conducted throughout the
796 world, including in the European Union (E.U.) and Canada (EP/CEU, 2006; MNHW,
797 1992). In addition, the World Health Organization (WHO) recommends the use of these
798 two organisms as water-quality indicators for recreational waters (WHO, 2003).
799
800 EPA NEEAR epidemiological study design and conclusions.
801 EPA conducted the NEEAR epidemiological studies at U.S. beaches in 2003, 2004, 2005,
802 2007, and 2009 and the results of these studies were reported in a series of research
803 articles (Wade et al., 2006, 2008, 2010; U.S. EPA, 2010d). These NEEAR studies were
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804 prospective cohort (PC) epidemiological studies that enrolled participants at the beach
805 (the cohort) and followed them for an appropriate period of time to compare incidence of
806 illness (i.e., NGI illness) between the exposed (swimmers) and unexposed groups. This
807 type of study can also include exposure response analyses if varying degrees of exposure
808 (such as water-quality data) are present (see Appendix B). The PC design used in
809 NEEAR studies was a modification of the cohort design previously employed by Cabelli
810 (1983), Dufour (1984), and numerous others (Calderon et al., 1991; Cheung et al., 1990;
811 Colford et al., 2005; Corbett et al., 1993; Haile et al., 1999; McBride et al., 1998; Prieto
812 et al., 2001; Seyfried et al., 1985; von Schirnding et al., 1992).
813
814 Investigators considered several different study designs, but only the randomized
815 controlled trial (described below) and prospective designs were viewed as potentially
816 viable methods to address the specific goals of the study. The cohort design adopted for
817 these studies modified and improved the design used for studies in the development of
818 the 1986 criteria (U.S. EPA, 1986). Attributes of the NEEAR studies' design include: (1)
819 the studied population of beach-goers is representative of all beach-goers; (2) the ability
820 to recruit many swimmers and nonswimmers; (3) the studies can be conducted over an
821 entire season, capturing and observing variability in the water quality; (4) potentially
822 sensitive groups who use the beach, such as children, the elderly, and the
823 immunocompromised are represented in the sample; and (5) the matrix water-sampling
824 design allows flexibility in determining monitoring options and allows short-term (hours)
825 variability in water quality to be evaluated.
826
827 The criteria used to select the seven beaches studied between 2003 and 20073 include:
828 1. The beach is an officially designated recreational area near a large population
829 center.
830 2. The beach has an attendance large enough to support an epidemiological study
831 (e.g., 300-400 attendees/day).
832 3. The age range of the swimmers is broad (i.e., includes children, teenagers, and
833 adults).
834 4. The beach generally meets the state or local WQSs with a range of concentrations.
835 5. The range of indicator concentration is related to occasional contamination by an
836 identified human source of pollution (point-source).
837 6. The swimming season is at least 90 days long.
838
839 In addition to the above criteria, obtaining agreement and consent from the local
840 community and beach or park management was necessary.
841
842 The enrollment goal was to approach and offer enrollment to all beach-goers between
843 11:00 AM and 5:00 PM. Interviewers approached beach-goers on weekends and holidays
844 during the summer. The health survey was administered in three parts: enrollment, exit
845 interview, and telephone interview. The beach interview included questions about
846 demographics, swimming and other beach activities, consumption of raw or undercooked
847 meat or runny eggs, chronic illnesses, allergies, acute health symptoms in the past 48
3 Criteria for selecting urban run-off and tropical beaches included other selection criteria as well (see
Appendix B.2).
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848 hours, contact with sick persons in the past 48 hours, other swimming in the past 48
849 hours, and contact with animals in the past 48 hours. The telephone interview was
850 conducted 10-12 days after the beach visit, and consisted of questions about health
851 symptoms experienced since the beach visit and other swimming or water-related
852 activities, contact with animals, and consumption of high-risk foods since the beach visit,
853 among others.
854
855 The goal of the data analysis was to evaluate the relationship between novel and rapid
856 measures of water quality and health effects and, by doing so, determine whether the new
857 approaches to measuring water quality would be useful in protecting beach-goers health
858 by accurately predicting swimming associated illness.
859
860 Regression models were the primary method used to determine the strength and the
861 significance of the relationship between the indicator measures and health effects. The
862 types of models used are an improvement over those used in the development of the 1986
863 criteria because they use individual-level data and do not rely on grouping of data points.
864 Grouping of the 1986 data resulted in the loss of the ability to account for individual
865 differences, such as age, sex, and other health conditions. The individual-level analysis
866 results in better control over these and other factors that might differ among individuals
867 (covariates or confounding factors). Nearly all the studies conducted in recent years have
868 used similar models, usually logistic or log-linear models (Fleisher et al., 1993; Haile et
869 al., 1999; Kay et al., 1994; McBride et al., 1998; Prieto et al., 2001; Seyfried et al., 1985).
870 The models used for the NEEAR data analysis are similar, but include several
871 modifications to the usual approach employed by these studies (Wade et al., 2008 and
872 2010).
873
874 Statistical tests were conducted using several approaches and models to assess whether
875 the odds ratios for the different fresh water and marine beaches were statistically
876 different. The regression models considered many potential covariates, including age,
877 sex, race, contact with animals, contact with other persons with diarrhea, number of other
878 visits to the beach, any other chronic illnesses (GI, skin, asthma), digging in sand, and
879 consumption of raw or undercooked meat.
880
881 As a result of the statistical analyses, EPA concluded that epidemiological data from
882 POTW-impacted temperate fresh waters and marine waters could be combined. A direct
883 comparison of the slope parameters (the change in illness rate per unit change in
884 enterococci CCE) shows no difference (p = 0.44) between the marine and fresh water
885 beaches. There were no significant differences in risk estimates from separate models
886 from marine and fresh water beaches separately or from the combined model. The results
887 indicated that for the maj ority of the range of exposures observed there were no
888 significant differences in the estimated risk levels for marine and fresh waters. Thus,
889 based on these NEEAR epidemiological study results, the relationship between the
890 Enterococcus qPCR levels and illness did not differ across POTW-impacted temperate
891 fresh water and marine beach sites (U.S. EPA, 201 la). For additional information, see
892 Appendix B.
893
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894 As part of the NEEAR epidemiological study design, EPA collected data from seven
895 POTW-influenced temperate fresh water and marine water beaches at intervals
896 throughout the day at different water depths. EPA collected 18 water samples each day
897 for each study. Water samples were collected three times daily (at 0800 hr, 1100 hr, and
898 1500 hr); two water samples were collected along each of three transects perpendicular to
899 the shoreline, one in waist-high water (1 m deep) and one in shin-high water (0.3 m
900 deep). The association between the qPCR average of the enterococci sample collected at
901 0800 hr and GI illness was nearly identical to the daily GM of all samples collected.4 The
902 GM of the 18 daily samples provided a single daily value for the health relationship
903 analysis. For the four fresh water beaches and the three marine beaches, enterococci were
904 positively associated with swimming-associated NGI illnesses (Wade et al., 2008, 2010).
905
906 A number of FIB were examined in the NEEAR studies (see Table 1). The occurrence of
907 GI illness in swimmers was positively associated with exposure to levels of enterococci
908 enumerated with EPA's Enterococcus qPCR method A in fresh waters and marine waters
909 (Wade et al., 2008, 2010). GI illness in swimmers at marine waters was also associated
910 with exposure to levels of anaerobic bacteria of the order Bacteroidales enumerated with
911 EPA's Bacteroidales qPCR method (Wade, 2010). The correlation between GI illness
912 and enterococci measured by culture in the NEEAR studies was positive, but not as
913 strong as the qPCR relationship to illness. No associations between adverse health
914 outcomes and any of the other fecal indicator organisms were observed in either the fresh
915 water or marine beach studies. Culturable E. coli was not included in the NEEAR
916 epidemiological studies because EPA had decided at the time to evaluate a single
917 indicator that it could potentially recommend for use by States in both marine and fresh
918 waters. Although cultured E. coli samples were not included in the NEEAR
919 epidemiological studies, other researchers confirm that culturable E. coli remains a useful
920 indicator of contamination in fresh waters (Marion et al., 2010).
921
922 Table 1. Fecal indicator organisms and enumeration methods tested in the NEEAR
923 epidemiological studies.
EPA Epidemiological
Study
Great Lakes
2007 Marine
Tropical
Urban Runoff
Indicator/Methods Tested in Study
Enterococcus measured by qPCR, enterococci measured by
culture, Bacteroidales measured by qPCR
Enterococcus measured by qPCR, enterococci measured by
culture, E. coli measured by qPCR, Bacteroides
thetaiotamicro (potentially human associated) measured by
qPCR, Bacteroidales, male-specific coliphage measured by
antibody assay, Clostridium spp. measured by qPCR
Same as 2007 marine, but no coliphage
Same as 2007 marine, but no coliphage
924
4 The association between the 0800-hr sample and health is potentially important from an implementation
perspective. These results indicate that a sample taken at 0800 hr could be used for beach-management
decisions on that day.
19
-------
12-9-11
925 In addition to the seven temperate, POTW-influenced beaches, EPA conducted PC
926 epidemiological studies at two other beaches in 2009: a temperate beach in Surfside,
927 South Carolina that is impacted by urban run-off sources but has no POTW sources, and
928 a tropical beach in Boqueron, Puerto Rico that is impacted by a POTW. Boqueron was
929 selected as an epidemiological study site to specifically examine the health relationships
930 of the indicators in a tropical setting. For both studies, the illness levels were found to be
931 low and no correlation between illness and indicator levels was observed (significant
932 inhibition, however, was reported for water samples measured by qPCR in the tropical
933 beach study) (U.S. EPA, 2010d). The very low indicator levels are likely an important
934 reason for the absence of a demonstrated relationship between FIB and health at both
935 sites.
936
937 Other Epidemiological Studies.
938 Findings from epidemiological studies conducted by non-EPA researchers were also
939 reviewed and considered during the development of the RWQC. Numerous
940 epidemiological investigations have been conducted since the 1950s to evaluate the
941 association between illness risk to recreational water users and the concentration of
942 suitable fecal indicators (Reviewed in U.S. EPA, 2009b). These studies have been
943 conducted in Australia, Canada, Egypt, France, Hong Kong, Israel, the Netherlands, New
944 Zealand, Spain, South Africa, the United States, and the United Kingdom. Most of these
945 studies investigated waters that were impacted or influenced by wastewater effluent.
946 Several groups of researchers have compiled information and generated broad and wide-
947 ranging inferences from these epidemiological studies (Priiss, 1998; Wade et al., 2003;
948 Zmirou et al., 2003). For example, a systematic review and meta-analysis of 27 published
949 studies evaluated the evidence linking specific microbial indicators of recreational water
950 quality to specific health outcomes under non-outbreak (endemic) conditions and
951 concluded that: (1) enterococci andE. coli are indicators of fecal contamination in fresh
952 waters and demonstrated predictors of GI illness in fresh waters, and enterococci in
953 marine waters, but FC are not; and (2) the risk of GI illness is considerably lower in
954 studies with enterococci and E. coli densities below those established by EPA in 1986
955 (Wade et al., 2003).
956
957 As of the date of the draft RWQC, EPA received data from SCCWRP, which were
958 generally consistent with the NEEAR study findings. However, because results were
959 preliminary in nature, they were not considered quantitatively.
960
961 A PC epidemiological study at an Ohio reservoir (a fresh water inland beach) provided an
962 indicator-illness relationship that agrees with EPA's earlier epidemiological studies
963 conducted at fresh water beaches (Dufour, 1984; Marion et al., 2010). In this study, E.
964 coli levels (EPA Method 1603; U.S. EPA, 2002a) were associated with HCGI in a
965 statistically similar manner as in EPA's 1970s and 1980s epidemiological studies (U.S.
966 EPA, 201 Of; see Appendix A).
967
968 Several epidemiological studies have been conducted using study designs that differ from
969 the NEEAR design, such as those referred to as randomized control trials (RCT) or
970 randomized exposure trials (see below). The RCT is an epidemiological experiment in
20
-------
12-9-11
971 which the study subjects are randomly allocated to groups to receive an experimental
972 procedure, manner, or intervention. For recreational water exposures, the groups are
973 bathers and nonbathers (swimmers vs. nonswimmers). The bathers are instructed as to
974 their time in the water and activities. Similar to a PC study, bathers and nonbathers must
975 be followed for an appropriate time to assess illness incidence and the effect of other
976 biases and potential confounders. Exposure-response analyses may be conducted for this
977 purpose.
978
979 Among the purported merits of RCT study designs are that they (1) better account for the
980 possibility that those who do not bathe choose not to do so based on factors other than
981 water quality, (2) associate individuals and the incidence of illness with the water quality
982 at the time and place of bathing, and (3) account for non-water-related risk factors (Kay,
983 et al., 1994). One of the most significant limitations of RCT is that the exposures in the
984 study are not necessarily representative of those experienced by the general population.
985
986 EPA reviewed and qualitatively considered the results from these studies, to the
987 maximum extent possible. For example, the E.U. used epidemiological studies to support
988 their WQSs (EP/CEU 2006). An RCT was conducted over four bathing seasons
989 (summers) at a different marine beach each season in the United Kingdom. Trends in
990 gastroenteritis (equivalent to GI illness) rate with increasing enterococci exposure were
991 not significantly different between sites, and data from the four beaches were pooled
992 (Kay et al., 1994). The source of FIB in this study was reported as domestic sewage.
993 Gastroenteritis was defined as "all cases of vomiting or diarrhea or all cases of nausea,
994 indigestion, diarrhea or vomiting that was accompanied by a fever". Rates of
995 gastroenteritis were significantly higher in the exposed group than the unexposed group
996 and adverse health effects were identified when the FIB density exceeded 32 per 100ml
997 (Kay et al., 1994; Fleisher et al., 1998). Another E.U. randomized control trial at five
998 fresh water bathing sites in Germany recommended the following guidance values for
999 water quality: 100 E. coli cfu per 100 mL and 25 enterococci cfu per 100 mL, based on
1000 the no observable adverse effects levels (NOAELs) for gastroenteritis (Wiedenmann et
1001 al., 2006).
1002
1003 Additionally, a randomized exposure epidemiological study at a Florida marine beach not
1004 impacted by a POTW found that those randomized to head immersion were
1005 approximately twice as likely to develop a skin rash when swimming in water with
1006 culturable enterococci levels greater than or equal to 40 cfu per 100 mL, than swimmers
1007 exposed to enterococci levels less than 40 cfu per 100 mL (Fleming et al., 2008;
1008 Sinigalliano et al., 2010).
1009
1010 Not all epidemiological studies show a clear correlation between indicator levels and
1011 health outcomes. For example, in a 1989 PC epidemiological study at marine beaches
1012 impacted by sewage outfalls and stormwater overflows in Sydney, Australia,
1013 gastrointestinal symptoms did not increase with increasing counts of FC or enterococci
1014 (Corbett et al., 1993). In a PC epidemiological study at Mission Bay, in California, where
1015 birds were the primary fecal source, only male-specific coliphage had a correlation with
1016 illness (Colford et al., 2005).
21
-------
12-9-11
1017
1018 3.2.4 Establishing a Comparable Illness Rate for Defining Culture and qPCR
1019 Thresholds
1020
1021 The 2012 RWQC values for cultureable levels of enterococci for marine and fresh waters
1022 and E. coli for fresh waters, if adopted by a State in its WQSs, would correspond to the
1023 same level of water quality established by the 1986 criteria in terms of indicator density,
1024 if the State had WQS consistent with EPA's 1986 criteria recommendations (U.S. EPA,
1025 1986). They assume this level of water quality would be determined by culturable levels
1026 of enterococci for marine waters and fresh waters and E. coli for fresh waters.
1027
1028 The NEEAR studies provided additional culturable enterococci data that EPA used to
1029 help estimate an illness rate associated with the recommended level of water quality. The
1030 NEEAR culture-based data were analyzed in several ways, some of which differed from
1031 the reported approach with the NEEAR qPCR-based data. EPA conducted these analyses
1032 to provide a comparison with the data analysis underlying the 1986 criteria for
1033 recreational waters. The following details describe EPA analytical approaches to evaluate
1034 the culture-based data. Taken together, these analyses indicate that the illness level
1035 associated with the 2012 RWQC water quality recommendations is approximately 6 to 8
1036 cases of HCGI per 1,000 recreators in both fresh and marine waters. The HCGI illness
1037 rate metric was used in these analyses, rather than the NGI employed in the NEEAR
1038 studies, in order to maintain comparability to the 1986 criteria.
1039
1040 Approach 1.
1041 As reported by Wade et al. (2008, 2010), culture-based measures of enterococci collected
1042 in the NEEAR studies were analyzed using the same rigorous statistical approach applied
1043 to the qPCR data (Wade et al., 2008, 2010). This approach did not result in a statistically
1044 significant illness association over the entire range of observed water quality measured by
1045 culturable enterococci using the fresh water, marine, or combined beach datasets (Wade
1046 et al., 2008, 2010). Therefore, EPA is not relying quantitatively on those exposure-
1047 response relationships because the regression coefficients would have little predictive
1048 value and may be misleading.
1049
1050 EPA's fresh water NEEAR studies, however, did indicate that swimmers exposed above
1051 the guideline value of 33 cfu per 100 mL had higher risks than nonswimmers or
1052 swimmers exposed below this value (Wade et al. 2008). Additionally, during EPA's
1053 marine water NEEAR studies, approximately 16 percent of the marine study days
1054 exceeded the enterococci GM value of 35 cfu enterococci per 100 mL. Similar to the
1055 fresh water NEEAR studies, odds of diarrhea, respiratory illness and earache were
1056 elevated among swimmers compared to non-swimmers on these study days (Wade et al.,
1057 2010).
1058
1059 Approach 2.
1060 EPA also used the NEEAR study statistical approach (Wade et al., 2008, 2010) to
1061 compare the swimmer-associated risk on days when cfu per 100 mL was above and
1062 below 33 cfu per 100 mL and 35 cfu per 100 mL for fresh and marine sites, respectively
22
-------
12-9-11
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
(Figure la). Those data indicate that (1) on days when the current GM guidelines values
were exceeded, illness rates were similar at marine and fresh water sites, (2) illness rates
at marine sites are likely less than the previously predicted 19 HCGI per 1,000, and (3)
average illness rates in marine and fresh water were on the order of 6 to 8 HCGI per
1,000 recreators.
Approach 3.
EPA then compared the distributions of fresh water and marine swimming-associated
HCGI rates observed in the NEEAR study to that of the corresponding 1986 illness rates.
Results of this analysis indicate that the distribution of NEEAR fresh water swimming-
associated HCGI rates was consistent with that observed in the earlier studies (Figure Ib).
Boxes in Figure Ib represent the middle 50 percent of the data, which intersect over most
of their range between these two fresh water data sets. (Note that the whiskers describe
the 10th and 90th percentiles, while the lines within the boxes indicate the median values).
In contrast, marine swimming-associated HCGI rates were considerably higher than fresh
water rates in the 1980s, showing no commonality among the middle 50 percent. This
observation explains the greater level of HCGI risk that was estimated for marine beaches
in the 1986 criteria, at 19 cases per 1,000 in marine waters versus 8 cases per 1,000 in
fresh water. Among the NEEAR beaches, however, the distribution of marine swimming-
associated HCGI rates is similar to that of both the NEEAR and the 1986 fresh water
rates, consistent with the results presented in Figure la.
1 1 95% C
• Estima
e
(
is so
a)
b)
Figure 1. Swimming-associated HCGI Illness levels observed during EPA's
epidemiological studies, a) risk on days with GM above 35 cfu at marine sites and
above 33 cfu per 100 mL at fresh water sites, b) illness observed during 1986 and
NEEAR studies
Approach 4.
EPA next attempted to compare the behavior of culturable data with respect to GI illness
from the NEEAR studies to the results of the 1986 analyses (Cabelli, 1983; Dufour,
1984). EPA could not reanalyze the 1980s data using the newer and more rigorous
NEEAR analytical approaches because the raw data from those earlier studies are no
longer available. Therefore, EPA used the same analytical approaches employed in the
23
-------
12-9-11
1099 1980s studies to evaluate the comparability of the NEEAR data with the results from the
1100 1980s.
1101
1102 In the 1986 criteria, quantitative relationships between the rates of swimming-associated
1103 illness and FIB densities were determined using regression analysis. Linear relationships
1104 were estimated from data grouped in two ways: (1) pairing the GM indicator density for a
1105 summer bathing season at each beach with the corresponding swimming-associated GI
1106 rate for the same summer (fresh water beaches), and (2) by trial days with similar
1107 indicator densities from each study location (marine beaches). The second approach,
1108 grouping by trial days with similar indicator densities, was not possible with the 1980s
1109 fresh water data because the variation of bacterial indicator densities in fresh water
1110 samples was not large enough to allow such groupings (U.S. EPA, 1986). For the 2012
1111 RWQC, EPA evaluated both approaches with the NEEAR culture-based enterococci data
1112 (seasonal and days of similar water quality) to estimate the illness associated with the
1113 recomm ended 1 evel of water qual ity.
1114
1115 Using the NEEAR culture-based enterococci data, the first analyses summarized each
1116 NEEAR beach as a seasonal GM of water quality and its average seasonal illness rate
1117 estimate, using the entire body of culturable enterococci data from the NEEAR studies.
1118 Illness rates were translated from NGI case definition to the older HCGI case definition
1119 to be able to compare NEEAR epidemiological results to 1986 results (U.S. EPA, 201 la).
1120 These data points generally fell within the predicted range of the published
1121 epidemiological regressions (Cabelli, 1983; Dufour, 1984). However, this analysis
1122 proved to be insufficient to estimate NEEAR study illness estimates, because only seven
1123 data points—one for each of the NEEAR beaches—were available.
1124
1125 EPA then examined the NEEAR culture-based enterococci data consistent with the
1126 analytical approach utilized for the marine water studies in the 1986 criteria by
1127 aggregating days of similar water quality (bins) for each beach (Cabelli, 1983; U.S. EPA
1128 1986). The NEEAR data were sorted by the observed GM for each beach day and the
1129 data for each beach were grouped according to natural breaks in these data. Bins of beach
1130 days were established from these data to balance, to the extent feasible, the existence of
1131 natural breaks of days with similar culturable enterococci GM and the number of study
1132 participants represented in each bin (Table 2). The binned data for all seven NEEAR
1133 beaches resulted in more data points per beach for both fresh water and marine beaches
1134 (Figures 2 and 3), which provided a greater level of resolution to the data compared to the
1135 seasonal-level fresh water analysis described above. Illness rates were also translated into
1136 HCGI equivalents.
1137
1138 EPA compared both fresh water and marine culture-based NEEAR indicator data to the
1139 corresponding 1986 regressions using the binned data. Results of this analysis indicate
1140 the vast majority of these data points fall within the 95th percentile prediction intervals
1141 derived from the 1986 regression models (Figure 2). The prediction intervals can be used
1142 to assess whether the additional data fall within an expected range based on the 1986
1143 data. While, the NEEAR marine culture-based data cluster at the lower end of the water
1144 quality and illness distribution described by the 1986 marine regression, they occur in a
24
-------
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
12-9-11
similar range of water quality and illness that was observed in the fresh water studies
(Figure 3). Because this analysis does not take into account the individual and beach-
level factors that may affect the association, EPA is only using this analysis to describe
the potential range of illness associated with the water quality level recommended in the
2012 RWQC for marine and fresh waters, (logio of 35 = 1.54 and logio of 33 = 1.52,
respectively). Based on this analysis, the corresponding mean estimate of illness ranged
approximately from 6 to 8 cases of HCGI per 1,000 recreators for both fresh waters and
marine waters (Figure 3).
Table 2. NEEAR culture-based enterococci and illness rate data for each of the
seven beaches.
Beach
West Beach
(fresh)
Huntington
Beach
(fresh)
Silver Beach
(fresh)
Washington
Park Beach
(fresh)
Edgewater
Beach
(marine)
Fairhope Beach
(marine)
Goddard Beach
(marine)
Daily
geometric
mean
Enterococcus
density
(CFU/100 ml)
1.6
9.2
25.1
110.4
4.7
9.2
15.7
81.1
7.0
14.8
25.8
51.3
106.6
8.4
17.2
27.9
44.6
2.3
10.0
18.9
77.7
5.5
12.7
24.1
81.0
2.6
18.8
Total number
interviewed
1122
726
463
553
731
733
526
850
864
2203
3128
2525
2152
722
789
1368
1465
555
239
441
108
494
541
351
629
2433
535
Number
reporting no
water
contact
360
144
101
117
426
391
251
467
220
603
900
808
843
198
171
364
524
135
66
152
27
261
200
126
266
1322
262
Number
reporting
immersion
556
468
299
344
186
208
167
196
490
1215
1720
1281
945
398
488
764
710
173
77
139
40
120
186
114
225
596
183
Number
NGI cases
no contact
21
2
8
5
43
27
31
46
16
36
54
46
36
15
10
23
31
10
7
13
2
27
19
5
23
58
15
Number
NGI cases
immersion
60
39
28
42
18
33
22
28
37
89
138
98
68
30
45
60
71
13
10
19
5
9
20
11
22
33
15
Excess
HCGI
swimmers
(S/1000),
beach
average
non-
swimmer
illness rate
12.9
7.4
9.7
16.0
0.2
14.0
8.0
10.5
4.4
3.9
5.5
4.6
3.6
2.8
6.5
3.5
8.3
-2.0
10.1
11.7
9.1
-2.6
4.6
2.2
2.4
2.1
8.0
1156
25
-------
12-9-11
1157
1158
1159
1160
1161
1162
1163
40 •
35 •
S 30 •
£
•| 25
tf)
O
8 20-
Q) -1R
+J ID '
ro
O 10-
O
I
5 -
0 •
• 1 986 freshwater data
1986 95% prediction interval
D NEEAR freshwater data
/
/ D
D D X *
^ *n /n
'^^ _ /M
D Mn ^X"^
_X*&] 0r-i
r-i/^^ AQ D
• J"^ ^
CT* /-
0.5 1.0 1.5 2.0 2.5 3.0
LoglO Enterococci density/ 100mL
a)
b)
40-
35-
30-
25-
20-
15-
10-
5-
0-
-5-
•
A
1986 marine data
1986 marine regression
1986 95% Prediction Interval
NEEAR marine data
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
LoglO Enterococci density / 100ml_
Figure 2. NEEAR studies culture data aggregated by similar water quality and 1986
criteria data for (a) fresh water beaches and (b) marine water beaches.
1 165
1 166
1167
1 168
1 169
1 170
1171
1 172
1 173
25 -i
15 -I
O
§ 10 H
-------
12-9-11
1174 factor for predicting culturable enterococci levels at NEEAR beaches (see Appendix
1175 B.7).
1176
1177 Conclusion.
1178 Taken together, the set of approaches described above provide lines of evidence to refine
1179 the illness rate estimate associated with the recommended marine criterion for
1180 enterococci (i.e., 19 HCGI per 1,000 recreators was the best mean estimate available at
1181 the time in 1986, but it was accompanied by a wide range of uncertainty) and indicates
1182 that the recommended 2012 RWQC values are similarly protective of public health in
1183 both marine waters and fresh waters.
1184
1185 Derivation of an equivalent qPCR value.
1186 EPA then derived a value for enterococci measured by qPCR value comparable to the
1187 culture-based value based on an illness rate of 8 HCGI per 1,000 recreators for both fresh
1188 waters and marine waters computed from the combined NEEAR epidemiological
1189 regression model (Figure 4) (U.S. EPA, 201 la). This model was used rather than separate
1190 models for marine waters and fresh waters because EPA's analysis indicated that there
1191 was little evidence for differences in illness rate estimates obtained from separate models
1192 from marine and fresh water beaches and because the beach-specific separate models
1193 showed no statistical improvement over a single combined model (U.S. EPA, 201 la).
1194 Furthermore, results from the marine water and fresh water studies are sufficiently
1195 similar to allow combining the NEEAR marine water and fresh water data to give a
1196 single relationship between health effects and water quality measured with a new rapid
1197 method (U.S. EPA, 201 la). The relationship between swimming-associated illness in
1198 terms of NGI per 1,000 recreators and water quality developed from the combined marine
1199 and fresh water data is defined as follows:
1200
1201 Swimming associated NGI illness = -27.3 + 23.64 (mean Logic qPCR CCE/100 mL)
1202
27
-------
12-9-11
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
o
o
o
O
o:
!S
UJ
03
Dl
C
'£
£
s=
Swimming-associated illness
95% Confidence bound
10
100 1000
Enterococcus CCE/100ml (ddCT)
daily geometric mean
Figure 4. Swimming-associated NGI illness and daily average Enterococcus qPCR
CCE. All subjects, marine and fresh water beaches combined (Intercept= -0.0273,
Slope= 0.02364).
The illness level of 8 cases of HCGI per 1,000 recreators corresponds to an estimated 36
cases of NGI per 1,000 recreators based on a translation of the definition of NGI to HCGI
using a factor of 4.5 (U.S. EPA, 201 la). Thus, a qPCR-based GM value of 475 CCE
enterococci per 100 mL corresponds to 36 cases of NGI per 1,000 recreators. Based on
the regression model, the following equation was used to derive the qPCR value:
4.S*//CG/+27.3
qPCR Value =10
where:
23.64
qPCR = qPCR value in units of CCE per 100 mL
HCGI =HCGI illness rate5 in illnesses per 1,000 recreators
This approach to derive a comparable qPCR-based recommended value for enterococci
allows EPA to use all the data collected during the NEEAR studies, demonstrates a
consistent level of protection for enterococci enumerated with culture-based methods,
and provides a qPCR value for States that desire a more rapid enumeration technique for
beach monitoring.
Summary.
EPA's 2012 RWQC recommendations, if adopted into State WQSs, will correspond to
the same level of water quality associated with the previous 1986 criteria
See U.S. EPA (2011) for translation information of HCGI illness rate into the NEEAR illness rate.
28
-------
12-9-11
1227 recommendations. The analyses conducted with the NEEAR culture-based enterococci
1228 data allowed for a refined estimate of illness associated with the current level of water
1229 quality described by 35 cfu enterococci per 100 mL in marine waters and 33 cfu
1230 enterococci per 100 mL in fresh waters. Furthermore, the refined illness rate estimate
1231 range of 6 to 8 HCGI per 1,000 recreators applies to both fresh and marine waters. The
1232 illness rate of 8 HCGI per 1,000 recreators was used as the basis for developing a qPCR-
1233 based enterococci value. Visual representations of the separate fresh water and marine
1234 water health relationships can be found in Wade et al. 2008 and Wade et al. 2010.
1235
1236 3.3 Scope of Protected Population
1237
1238 EPA's 1986 criteria recommendations are supported by epidemiological studies that were
1239 conducted in the late 1970s and 1980s. Those studies enrolled participants according to
1240 the following criteria: "Whenever possible, family units were sought because information
1241 on multiple individuals could be obtained from one person, usually an adult member of a
1242 family. During this initial contact, the following information was obtained on each
1243 participant: sex, age, race and ethnicity" (Dufour, 1984). This enrollment strategy
1244 ensured that children were highly represented in those epidemiological studies. When
1245 EPA published the 1986 recommended criteria values, EPA related the water-quality
1246 level to the associated illness-rate level derived in the epidemiological studies conducted
1247 in the 1970s and 1980s. Thus, the illness rates corresponding to the 1986 criteria
1248 recommendations are based on the epidemiological relationship for the general
1249 population that includes children. EPA is proposing a similar approach for deriving
1250 illness levels for the 2012 RWQC.
1251
1252 As in the previous EPA epidemiological studies, children were well represented in EPA's
1253 NEEAR studies population. The proportions of individuals in the under 5-year and 5-
1254 to 11-year age categories that were enrolled in the epidemiological studies were greater
1255 than those present in the U.S. demographic. For example, at West Beach the proportion
1256 of children aged 10 years and under made up 20 percent of the study sample. A similar
1257 over-representation of children is true for the other beaches, including Huntington (20
1258 percent of the study sample), Washington Park (22 percent), Silver Beach (22 percent),
1259 Edgewater (17 percent), Fairhope (30 percent), and Goddard (20 percent). According to
1260 the U.S. Census data for 2009, children younger than 10 years of age make up
1261 approximately 14 percent of the U.S. population (Census, 2010). Based on national
1262 demographics, the NEEAR epidemiological studies included an over-representation of
1263 children.
1264
1265 EPA conducted statistical analyses of the data from each of EPA's epidemiological
1266 studies at fresh water, marine, and tropical beaches to evaluate whether children at these
1267 sites were at an increased risk of illness following exposure to recreational waters. The
1268 results for children were compared to adults and other age groups. The age groups used
1269 for comparison included the following: 10 years and under, 11 to 55 years, and over 55
1270 years of age. Other age groups for children were not separately analyzed due to small
1271 sample sizes. Data for children (i.e., 10 years and under) were specifically analyzed to
29
-------
12-9-11
1272 evaluate whether their behavior and/or physiology results in different illness rates
1273 compared to the general population.
1274
1275 In the NEEAR fresh water epidemiological studies, the association between GI illness
1276 and water quality, as measured by EPA's Enterococcus qPCR method A, was stronger
1277 among children (age 10 years and under) compared with the NEEAR general population,
1278 which also included children. Relative to body size, children breathe more air and ingest
1279 more food and water than adults (U.S. EPA, 2003). Children also exhibit behaviors that
1280 increase their exposure to environmental contaminants, including increased head and
1281 body immersion in recreational waters (Wade et al., 2006, 2008; U.S. EPA, 2010d) and
1282 hand-to-mouth contact (Xue et al., 2007). The immature immune systems of children can
1283 also leave them particularly vulnerable to the effects of environmental agents (Pond,
1284 2005). A higher proportion of children immerse their heads in shallow water compared
1285 with adults. Children also stay in the water longer than adults (Wade et al., 2006, 2008)
1286 and ingest more water (Dufour et al., 2006). These characteristics supported the
1287 hypothesis that a significant difference in GI illness in children in comparison to the
1288 general population could have been observed in the epidemiological studies.
1289
1290 In the NEEAR fresh water studies, however, there was considerable overlap in the
1291 confidence intervals associated with the estimated mean illness responses between
1292 children and the general population. The confidence intervals for the children's curve
1293 were wider than the confidence intervals for the general population. When health effects
1294 were compared with water quality, as measured by cultured enterococci, differences
1295 between children (age 10 years and under) and the general population were not observed
1296 (Wade et al., 2008). Swimmers exposed to water qualities above densities of 33 cfu per
1297 100 mL had an elevated risk of developing GI illness compared with non-swimmers and
1298 swimmers exposed to water having densities less than 33 cfu per 100 mL. Both cohorts,
1299 including children (age 10 years and under) and the general population, demonstrated
1300 similar responses to water having more than 33 cfu per 100 mL.
1301
1302 In the NEEAR marine epidemiological studies, there was insufficient evidence of
1303 increased illness among children corresponding to water quality as measured by qPCR.
1304 As with the fresh water sites, a higher proportion of children age 5 to 10 years (75
1305 percent) would immerse their bodies or head in the water compared with adults over age
1306 55 years (26 percent) (Wade et al., 2010). Elevated GI illness levels were observed
1307 among swimmers of all age groups compared with non-swimmers on days that exceeded
1308 the enterococci GM value of 35 cfu per 100 mL (Wade et al., 2010).
1309
1310 The epidemiological studies conducted by EPA in tropical regions (Boqueron Beach,
1311 Puerto Rico) and temperate marine waters that were impacted by urban runoff (Surfside
1312 Beach, South Carolina) showed no evidence of increased illness in children that
1313 corresponded to exposure to FIB in the recreational waters (U.S. EPA, 2010d).
1314
1315 EPA considered children's unique physiological and behavioral characteristics when
1316 developing these criteria. The collective results of the NEEAR epidemiological studies,
1317 however, provide inconclusive evidence that children (age 10 years and under) exhibited
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1318 a significantly different illness response given the range of water qualities measured in
1319 these studies.
1320
1321 Another subpopulation of participants, those over the age of 55 years, was also present
1322 but at levels too low to be evaluated separately. For example, in the fresh water studies,
1323 this subgroup represented 7 percent of the study population. This small sample size did
1324 not allow EPA to make any conclusions about risk in the subpopulation over 55 years of
1325 age. EPA's NEEAR studies were also not designed to evaluate the effects on groups with
1326 compromised immune systems or other vulnerable subpopulations.
1327
1328 EPA considered all the demographic data and results presented above and concluded that
1329 the robustness of the estimates for the general population data provide a significant
1330 advantage over the more uncertain and smaller sample set that consisted only of children.
1331 Importantly, the general population data are weighted to include children in a robust
1332 manner. Thus, the general population data provide an appropriate basis for deriving
1333 EPA's recommended values for the 2012 RWQC.
1334
1335 The 2012 RWQC document includes information for States on an additional protective
1336 option for children through implementation of qPCR for site-specifically, which would
1337 allow families to make real-time decisions to protect their children. In contrast to the
1338 "rapid" methods, such as qPCR, traditional culture methods provide estimates of water
1339 quality a day or two after the actual exposure. qPCR can be performed in 2-6 hours and
1340 has been shown to be successful when implementing same-day health-protective
1341 decisions (Griffith and Weisberg, 2011). Predictive models will also be available for
1342 rapid notification with these new criteria for the measurement of E. coli and enterococci
1343 by culture and qPCR as presented in section 5.1.2. These models have been demonstrated
1344 to be useful tools for implementing beach monitoring programs in the Great Lakes
1345 (Francy, 2009; Frick et al., 2008; Ge and Frick, 2009). Because children may be more
1346 exposed and more sensitive to pathogens in recreational waters, it is imperative that
1347 effective risk communication and health outreach be done to effectively mitigate
1348 exposure to contaminated waters. Alerting families with children to the level of water
1349 quality on a given beach day, in real time, will allow for better protection of children.
1350
1351 3.4 Waterbody Type
1352
1353 EPA's 2012 RWQC national recommendations are for all surface waters of the United
1354 States designated by a State for swimming, bathing, surfing, or similar water contact
1355 activities. Historically, the scientific evidence used to generate criteria recommendations
1356 has been based on data collected mostly from coastal, temperate and Great Lakes
1357 freshwaters. The stakeholder community has asked EPA to consider whether EPA's
1358 criteria recommendations could be used to develop State WQSs for other types of waters.
1359
1360 In response, EPA conducted a review of the available information comparing coastal
1361 (including Great Lakes and marine) and non-coastal (including flowing and non-flowing
1362 inland waters, such as streams, rivers, impoundments, and lakes) waters to evaluate
1363 whether EPA should include recommendations in the 2012 RWQC for all waterbody
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1364 types (U.S. EPA, 2010g). Additionally, EPA considered the WERF Inland Water
1365 Workshop report (WERF, 2009) and subsequent meeting report publication (Dorevitch et
1366 al., 2010), which concluded that the inclusion of non-coastal waters in the 2012 criteria
1367 will result in public health protection, by preventing illnesses associated with exposure to
1368 non-coastal waters if States adopt WQS based on EPA's 2012 RWQC recommendations.
1369 Additionally, outbreaks from exposure to non-coastal waters indicate a need for public
1370 health protection in such settings. FIB monitoring can be used as a way to reduce the
1371 occurrence of outbreaks of severe illness, as well as the sporadic cases of illness that
1372 occur among swimmers. Overall, the distinction of non-coastal waters versus coastal
1373 waters is of less importance than more fundamental variables such as the source of fecal
1374 contamination, scale of the body of water, and the effects of sediment, which translate
1375 into differences in the densities, transport, and fate of indicators and pathogens
1376 (Dorevitch et al., 2010). The next two subsections describe the scope of the currently
1377 available data that EPA considered supporting the revision of criteria that include both
1378 coastal and non-coastal waters. For additional information on the EPA report, see
1379 Appendix B.6.
1380
1381 Waterbody type and sources of fecal contamination.
1382 EPA's literature review identified the source of fecal pollution as one of the most
1383 important factors when considering the potential differences between EPA
1384 epidemiological study sites and non-coastal waters (U.S. EPA 2010g). More information
1385 specifically concerning the source of fecal contamination is found in section 3.5. Sources
1386 of fecal contamination are discussed in this section only insofar as they potentially impact
1387 FIB in coastal versus non-coastal settings.
1388
1389 All surface waters receive FIB from point sources, diffuse sources (which may consist of
1390 point source and non-point source pollution), direct deposition, and resuspension of FIB
1391 contained in sediments. Loadings and hydrodynamics of FIB in POTW-impacted coastal
1392 and non-coastal waters are generally similar. POTW discharges, which are known
1393 sources of human-derived pathogens and indicators from fecal pollution, are relatively
1394 steady. Differences exist in FIB loadings between POTW-impacted coastal and non-
1395 coastal waters, and non-coastal waters impacted by sources other than treated sewage
1396 effluent due to differences in the physical and biological characteristics that influence
1397 FIB survival compared to pathogen survival. Some of the characteristics include potential
1398 and extent of shading, hydrodynamics, potential for sedimentation, and microbial
1399 ecology.
1400
1401 Differences can exist between coastal and non-coastal waters that could affect the
1402 relationship between FIB levels and adverse health effects, including the type of fecal
1403 source impacting the waterbody and the differences in fate and transport of pathogens
1404 and FIB in the receiving waters. For example, POTW effluents are a continual loading
1405 event, whereas fecal contamination from other sources, particularly non-point sources,
1406 occurs primarily during precipitation events. Pathogens and FIB in rain event-driven fecal
1407 loadings could be affected by the different transport characteristics in coastal versus non-
1408 coastal waters.
1409
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1410 Epidemiological studies in non-coastal waters.
1411 EPA also evaluated the available epidemiological evidence in non-coastal waters. Only a
1412 handful of studies have been conducted in small lakes and even fewer in inland flowing
1413 waters. Among those, one of the epidemiological sites for earlier EPA studies (Dufour
1414 1984) was a small inland lake in Oklahoma, which helped provide the basis for the 1986
1415 criteria.
1416
1417 Ferley et al. (1989) conducted a retrospective study in the French Ardeche basin to assess
1418 the relationship between swimming-related morbidity and the bacteriological quality of
1419 the recreational water. Tourists (n = 5737) in eight holiday camps were questioned about
1420 the occurrence of illness and their bathing habits during the week preceding the
1421 interviews. GI illness was higher in swimmers than in non-swimmers. Fecal streptococci
1422 (FS) were best correlated to GI illness. Direct linear regression models and FC did not
1423 predict risk as well. The concentration of FS above which bathers exhibited higher illness
1424 rates than non-bathers was as 20 FS per 100 mL.
1425
1426 A series of RCT epidemiological studies was conducted in Germany to establish the
1427 association of illness with recreational use of designated fresh recreational waters (four
1428 lakes and one river) (Wiedenmann et al., 2006). All study sites were considered to be in
1429 compliance with the European standards for total coliform and FC for at least the three
1430 previous bathing seasons. Sources of fecal contamination at the study sites included
1431 treated and untreated municipal sewage, non-point source agricultural runoff, and fecal
1432 contamination from water fowl. Based on the water quality measured as levels of E. coli,
1433 enterococci, somatic coliphages, or Clostridiumperfringens, and observed health effects,
1434 the authors recommended guideline values for each of these fecal indicator organisms.
1435 They noted that these values for E. coll and enterococci were consistent with EPA's 1986
1436 criteria for recreational water recommendations.
1437
1438 Epibathe, a public health project funded under E.U. Framework Programme 6 to produce
1439 "science support for policy" began in December 2005 and ended in March 2009. The
1440 imperative for this research effort was the relative paucity of E.U. data describing the
1441 health effects of controlled exposure (head immersion) in E.U. fresh waters and
1442 Mediterranean marine waters. Both aquatic environments provide important recreational
1443 resources throughout the E.U. (European Commission-Epibathe, 2009). Epibathe
1444 comprised a series of marine and fresh recreation water epidemiological studies
1445 conducted in 2006 and 2007 in Spain and Hungary, respectively. Four riverine
1446 recreational sites were assessed in Hungary and four coastal sites were assessed in Spain.
1447 All sites were in compliance with the European standards specified in the E.U. bathing
1448 Water Directive (EP/CEU, 1976). For E.U. marine waters (Spain and the U.K. RCT
1449 studies), the clearest trend in increasing risk of illness with decreasing water quality was
1450 evident using enterococci as an indicator of water quality. For fresh waters (German and
1451 Hungary RCT studies), the clearest indicator-illness relationship between GI symptoms
1452 and water quality was seen with E. coll. Both analyses (fresh waters and marine waters)
1453 suggest elevations in GI illness in the controlled exposure (head immersion) cohorts. The
1454 authors concluded that the empirical field studies and combined data analysis suggested
1455 that the WHO or E.U. water quality standard recommendations did not need to be
33
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1456 revised. Additionally, EPA concluded that these results provide further evidence that the
1457 E.U.-recommended E. coll and enterococci guidelines values are consistent with the 1986
1458 criteri a for recreati onal waters.
1459
1460 A PC study was recently conducted at a small inland lake in Ohio (Marion, 2010). The
1461 study was undertaken to examine the illness rates among inland recreational water users.
1462 It also evaluated the effectiveness of E. coli as an effective predictor of GI illness risk
1463 among recreators. Human health data were collected during the 2009 swimming season at
1464 East Fork Lake, Ohio and adverse health outcomes were reported 8-9 days post-
1465 exposure. The authors concluded that E. coli was significantly associated with elevated
1466 GI illness risk among swimmers compared to non-swimmers. The risk of illness
1467 increased among swimmers with increasing densities of E. coli. The results of this study
1468 were consistent with prior fresh water beach studies used by EPA to develop the 1986
1469 criteria for recreational waters.
1470
1471 Based on the best available information, which is summarized above, EPA has
1472 determined that the 2012 RWQC recommendations are applicable to coastal and non-
1473 coastal waterbodies. Although some differences may exist between coastal and non-
1474 coastal waters, application of the recommended criteria in both water types would
1475 constitute a prudent approach to protect public health. States wishing to address site-
1476 specific conditions or local waterbody characteristics in their WQS should refer to section
1477 5 of this document for suggestions on approaches.
1478
1479 3.5 Sources of Fecal Contamination
1480
1481 In the 1986 criteria, EPA recommended:
1482 "the application of these criteria unless sanitary and epidemiological studies show
1483 the sources of the indicator bacteria to be nonhuman and that the indicator
1484 densities are not indicative of a health risk to those swimming in such waters.
1485 EPA is sponsoring research to study the health risk of non-point source pollution
1486 (NPS) from rural areas on the safety of water for swimming. Definitive evidence
1487 from this study was not available at the time of preparation of this criterion, but
1488 will be incorporated into subsequent revisions."
1489
1490 Section 303(i)(2)(A) required EPA to promulgate criteria for States as protective of
1491 human health as EPA's 1986 criteria where States had failed to do so for their coastal and
1492 Great Lakes waters. When EPA promulgated WQSs for those States based on the 1986
1493 criteria in 2004, EPA evaluated the scientific understanding of the human health risks
1494 associated with nonhuman sources of fecal contamination and concluded that although
1495 "[the] EPA's scientific understanding of pathogens and pathogen indicators has evolved
1496 since 1986, data characterizing the public health risk associated with nonhuman sources
1497 is still too limited for the [EPA] to promulgate [WQSs for States based on] another
1498 approach." Thus, the federally promulgated criteria values in the Rule were considered
1499 applicable regardless of origin unless a sanitary survey shows that the sources of the
1500 indicator bacteria are nonhuman and an epidemiological study shows that the indicator
1501 densities are not indicative of a human health risk. In addition, in evaluating whether
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1502 State standards were as protective of human health as EPA's 1986 criteria, EPA
1503 concluded that State WQSs with exemptions for non-human sources were not as
1504 protective of human health as EPA's 1986 criteria (See 69 FR at 67228).
1505
1506 EPA has continued to examine the potential for illness from exposure to nonhuman fecal
1507 contamination compared to the potential for illness from exposure to human fecal
1508 contamination. One of the key topics discussed at the Experts Scientific Workshop on
1509 Critical Research Needs for the Development of New or Revised Recreational Water
1510 Quality Criteria (U.S. EPA, 2007a) was different sources of FIB, including human
1511 sources and a variety of nonhuman sources (such as animals and the environment). EPA
1512 further investigated this topic in Review of Published Studies to Characterize Relative
1513 Risks from Different Sources of Fecal Contamination in Recreational Waters (U.S. EPA,
1514 2009b) and Review ofZoonotic Pathogens in Ambient Waters (U.S. EPA, 2009a). EPA
1515 recognizes the public health importance of waterborne zoonotic pathogens. However, the
1516 state of the science has only recently allowed for the characterization of the potential
1517 health impacts from recreational exposures to zoonotic pathogens relative to the risks
1518 associated with human sources of fecal contamination. Overall, however, the
1519 aforementioned reviews indicate that both human and animal feces in recreational waters
1520 pose potential threats to human health, especially in immunocompromised persons and
1521 subpopulations. For additional information, see Appendix C.
1522
1523 Humans can become ill from exposure to zoonotic pathogens in fecal contamination
1524 originating from animal sources. Livestock and wildlife carry both human pathogens and
1525 FIB, and can transmit these microbes to surface waters and other bodies of water (CDC,
1526 1993, 1996, 1998, 2000, 2002, 2004, 2006, 2008; USDA, 2000). Additionally, many
1527 documented outbreaks of potential zoonotic pathogens, such as Salmonella, Giardia,
1528 Cryptosporidium, and enterohemorrhagic E. coli O157:H7, could be of either human or
1529 animal origin, although providing proper source attribution for these outbreaks can be
1530 quite difficult. U.S. Centers for Disease Control and Prevention (CDC) reports have
1531 documented instances of E. coli O157:H7 infection resulting from exposure to surface
1532 waters, but the source of the contamination is not specified (CDC 2000, 2002). Other
1533 studies have linked recreational water exposure to outbreaks caused by potentially
1534 zoonotic pathogens, but the sources of fecal contamination in these waters were not
1535 identified (Valderrama, 2009; Roy, 2004; U.S. EPA 2009a). Although formal
1536 surveillance information is not comprehensive, Craun et al. (2005) estimated that 18
1537 percent of the 259 recreational water outbreaks reported to the CDC from 1970 to 2000
1538 were associated with animals.
1539
1540 One study documenting a 1999 outbreak of E. coli O157:H7 at a lake in Vancouver,
1541 Washington suggested that duck feces were the source of the pathogen causing the
1542 outbreak (Samadpour, 2002). More than 100 samples of water, soil, sand, sediment, and
1543 animal feces were collected in and around the lake and tested. E. coli O157:H7 was
1544 detected in both water and duck fecal samples. Genetic analyses of the E. coli isolates
1545 demonstrated similar results in the water, duck feces, and patient stool samples. Duck
1546 feces could not be confirmed as the primary source of the zoonotic pathogens, however,
1547 because the ducks could have been infected by the same source of contamination that was
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1548 present in the lake. Other notable outbreaks are discussed in the EPA's Review of
1549 Published Studies to Characterize Relative Risks from Difference Sources of Fecal
1550 Contamination in Recreational Water (Appendix C and U.S. EPA, 2009b).
1551
1552 Fecal contamination from nonhuman sources can transmit pathogens that can cause GI
1553 illnesses, such as those reported in EPA's NEEAR and other epidemiological studies.
1554 The potential human health risks from human versus non-human fecal sources, for a
1555 given level of water quality as measured by FIB, can be different, with certain non-
1556 bovine fecal sources potentially posing less risk (Seller et al. 2010b. and Schoen and
1557 Ashbolt, 2010).
1558
1559 Although EPA's research indicates that the source of contamination is critical for
1560 understanding the human health risk associated with recreational waters, there is
1561 variability in the amount of human health risk in recreational waters from the various
1562 fecal sources due to the wide-ranging environmental conditions that occur across the
1563 United States. EPA and others have documented human health impacts in numerous
1564 epidemiological studies in fresh waters and marine waters primarily impacted by human
1565 sources of fecal contamination (see sections 3.2 and 3.4 for a discussion of these studies).
1566 The cause of many of the illnesses, particularly those resulting from exposure to POTW
1567 effluent, is thought to be viral (USEPA, 1986, Seller et al., 2010a, Bambic et al., 2011).
1568
1569 While human sources of fecal contamination are fairly consistent in the potential human
1570 health risks posted during recreational exposure, non-human sources of fecal
1571 contamination, and thus the potential human health risks, can vary from site-to-site
1572 depending on factors such as: the nature of the non-human source(s), the fecal load from
1573 the non-human source(s), and the fate and transport characteristics of the fecal
1574 contamination from deposition to the point of exposure. Nonhuman fecal sources can
1575 contaminate recreational bodies of water via direct fecal loading into the body of water,
1576 and indirect contamination can occur via runoff from the land. The fate and transport
1577 characteristics of the zoonotic pathogens and FIB present under these conditions can be
1578 different (e.g., differences in attachment to particulates or differences in susceptibility to
1579 environmental parameters affecting survival) (see Appendix C.4). For more information
1580 on pathogenic risks from nonhuman sources, see Review of Zoonotic Pathogens in
1581 Ambient Waters (U.S. EPA, 2009a). EPA did not develop nationally applicable criteria
1582 values that adjust for the source of the fecal contamination, for non-human sources.
1583 Rather, EPA recommends that States use these nationally applicable criteria in all waters
1584 designated for primary contact recreation.
1585
1586 Few epidemiological studies have been conducted in waters impacted by nonhuman
1587 sources of fecal contamination resulting in an ambiguous understanding of the
1588 relationship between swimmer-associated illness and any of the conventionally
1589 enumerated FIB in those types of waters. For example, Calderon (1991) found a lack of a
1590 statistical association between swimmers' illness risk and FIB levels in a rural fresh
1591 waterbody impacted by animal fecal contamination; however, other researchers have
1592 commented that this lack of statistical association was likely due to the small study size
1593 and not a lack of potential human health risks (McBride, 1993). Another epidemiological
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1594 study conducted at a nonhuman, nonpoint source impacted beach at Mission Bay,
1595 California documented an increase in diarrhea and skin rash in swimmers versus non-
1596 swimmers, but the incidence of illness was not associated with any of the traditional FIB
1597 levels tested (Colford, 2007). The few studies conducted in non-POTW-impacted waters
1598 that also report significant health effects (McBride et al., 1998; Cheung, 1990; and
1599 Wiedenmann 2006) have (1) been conducted in highly animal-impacted scenarios, and
1600 (2) epidemiological data from beaches with nonhuman fecal source impacts combined
1601 with data from beaches impacted by human fecal contamination sources. McBride et al.
1602 (1998) conducted a separate analysis of the impact on human sources versus the impact
1603 of animal sources on beach sites in addition to evaluating the effects of both human and
1604 animal sources combined and concluded that illness risks posed by animal versus human
1605 fecal material were not substantially different. Thus, waterbodies with substantial animal
1606 inputs can result in potential human health risks on par with those that result from human
1607 fecal inputs.
1608
1609 Microbial risk assessment approaches are available to assist in characterizing potential
1610 human health risks from nonhuman sources of fecal contamination (Till and McBride,
1611 2004, Roser et al., 2006, Seller et al., 2010b, Schoen and Ashbolt, 2010). For example,
1612 New Zealand, where roughly 80 percent of the total notified illnesses are zoonotic and
1613 potentially waterborne, recently updated its recreational fresh water guidelines based on a
1614 risk analysis of campylobacteriosis (accounting for over half of the reported total
1615 notifiable disease burden in that country) and using E. coli as a pathogen indicator (Till
1616 and McBride, 2004). Since those waters were highly impacted by fecal contamination, in
1617 this case from agricultural sources, a predictable relationship between the pathogen and
1618 the FIB was able to be developed. The correlation between the occurrence of
1619 Campylobacter and E. coli may not hold in all waters, but this relationship was
1620 demonstrated in New Zealand, particularly in waters with high levels of Campylobacter
1621 and E. coli. Water quality guidelines based on this work resulted in values for E. coli,
1622 which when compared at similar estimated illness levels, are consistent with the 2012
1623 RWQC recommendations.
1624
1625 EPA determined that the current scientific understanding of the human health risks
1626 associated with the wide variation of exposures to nonhuman fecal contamination is
1627 insufficient to support development of separate nationally applicable 2012 RWQC for
1628 waterbodies impacted by nonhuman sources. The risk presented by fecal contamination
1629 from nonhuman sources varies and, has been shown in some cases, to be potentially less
1630 significant than the risk presented by fecal contamination from human sources (Seller et
1631 al., 2010a,b; Schoen and Ashbolt, 2010, Bambic et al., 2011). The number of cases where
1632 animals are suspected as being the likely cause of the contamination and resulting illness,
1633 however, present a strong case for not neglecting these sources altogether. EPA's
1634 research indicates that some nonhuman fecal sources (cattle in particular) may pose risks
1635 comparable to those risks from human sources; not all animal fecal material, however,
1636 presents the same level of risk (see Appendix C for additional details; Seller et al.,
1637 2010a,b; U.S. EPA, 2010a). Human pathogens are present in animal fecal matter, and
1638 there is, therefore, a potential risk from recreational exposure to human pathogens in
1639 animal-impacted waters. EPA feels that the state of the science is not developed
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1640 sufficiently for quantifying potential human health risks from non-human fecal
1641 contamination on a national basis given the site-to-site variability. For waters
1642 predominated by non-human sources and in the absence of site-specific criteria, EPA
1643 recommends that the national criteria should be used to develop WQS.
1644
1645 For these reasons, EPA has concluded that States adopting the 2012 RWQC, regardless
1646 of the source of fecal contamination, would result in WQSs protective of public health.
1647 EPA is not developing separate national criteria for nonhuman sources. States interested
1648 in addressing the potential human health risk differences from different sources of fecal
1649 contamination on a site-specific basis should refer to section 5.2.2 of this document for
1650 suggestions on approaches.
1651
1652 3.6 Expression of Criteria
1653
1654 In 1986, EPA recommended criteria for enterococci and E. coli that contain two
1655 components: a GM and an SSM. The 1986 criteria values were derived from separate
1656 beach water quality datasets that were averaged over the entire summer swimming
1657 season, as part of EPA's epidemiological studies conducted during the 1970s and 1980s.
1658 The GM is calculated as the antilog of the arithmetic mean of the log-transformed
1659 densities (Wymer and Wade, 2007). The SSM densities are based on the upper
1660 percentiles of the water quality distribution around the GM. Together, the GM and SSM
1661 describe a water quality distribution that would be protective of primary contact
1662 recreation, based on the epidemiological studies conducted at that time. Because the GM
1663 and SSM are components of the same water quality distribution, they are anchored to the
1664 same illness rate (e.g., 8 HCGI per 1,000 recreators).
1665
1666 The two components, however, serve different purposes for different CWA programs.
1667 For beach management, the SSM is given as a value that should not be exceeded,
1668 allowing States to determine when to make timely public notifications (i.e., advisories or
1669 closings). The 1986 criteria expression contains four different SSM values, corresponding
1670 to the 75th, 82th, 90th, and 95th percentile confidence levels. EPA recommended using
1671 different SSM percentiles based on a waterbody's use intensity. For NPDES or State
1672 permitting programs, water quality-based effluent limitations (WQBELs) for dischargers
1673 are to be calculated in accordance with 40 CFR §122.45, which requires WQBELS for
1674 continuous dischargers to be expressed as short-term (such as daily or weekly) and long-
1675 term (monthly) limits. These effluent limitations would be derived from the State's WQS
1676 which, if it is consistent with EPA's recommendations would include both a GM and an
1677 SSM value. When identifying those waters for which existing effluent limitations are not
1678 stringent enough to meet recreational WQS (i.e., determining attainment status) states,
1679 with standards consistent with EPA's 2012 RWQC recommendations, would use both the
1680 GM and SSM. Two clarifications to the 1986 criteria expression for determining
1681 attainment status for CWA §303(d) and §305(b) purposes using the GM and SSM are
1682 described below.
1683
1684 First, the 1986 criteria GM was meant to be compared to the calculated GM of the
1685 waterbody being assessed, using at least five samples taken over a 30-day period. As
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1686 stated in the preamble to EPA's promulgation of WQS for States in 2004 the GM is the
1687 more relevant value for protecting water quality because it is a more reliable measure and
1688 more directly linked to the underlying studies on which the 1986 criteria are based.
1689 However, the 2004 preamble also states that "EPA intends that States and Territories
1690 should retain discretion to use single sample maximum values as they deem appropriate
1691 in the context of Clean Water Act implementation programs other than beach notification
1692 and closure, consistent with the Clean Water Act and its implementing regulations (U.S.
1693 EPA, 2004)."
1694
1695 Secondly, if SSM's values are interpreted to be "never to be exceeded" values for
1696 assessing a waterbody, the resulting water-quality standard is much more stringent than
1697 needed to protect the designated use of primary contact recreation if the GM were used.
1698 For example, a marine body of water that is in compliance with the 1986 criteria for
1699 enterococci (i.e., GM = 35 cfu per 100 mL; estimated 75th percentile = 104 cfu per 100
1700 mL) would have a water-quality distribution such that 25 percent of the samples taken
1701 would be higher than 104 cfu per 100 mL. For a body of water to meet 104 cfu per 100
1702 mL as a "never to be exceeded" value, the GM of that body of water would need to be
1703 extremely low.
1704
1705 In the 2012 RWQC, to ensure public health protection and to minimize inconsistencies in
1706 the interpretation or application of the statistical construct, EPA is recommending that the
1707 criteria magnitude be expressed using two components: the GM and the estimated 75th
1708 percentile STV. The recommended GM and STV (essentially the STV represents a
1709 renaming of the previous SSM) values are described below.
1710
1711 The GM for a waterbody should be calculated in the same way it was calculated for the
1712 1986 criteria: 1) take the logic of the samples under consideration,6 2) average those
1713 values, and 3) raise that average to the power of 10. It is important to note that EPA'
1714 recommendations no longer include a recommendation to calculate the GM criterion over
1715 a period of 30 days. Epidemiological data, from which these criteria are derived, were
1716 evaluated on a seasonally basis. Thus, EPA recommends States to select a duration for
1717 both the GM and the STV between 30 days and 90 days. The duration for calculating the
1718 GM and associated STV should not exceed 90 days. The duration should be explicitly
1719 included in the State's WQS, as it is a component of the WQS. Including more samples in
1720 calculation of the GM and STV improves the accuracy of the characterization of water
1721 quality. If States decide to use a duration that is shorter than 90 days for the purposes of
1722 calculating waterbody GMs, please be aware that smaller number of samples increases
1723 the chance of misclassification and careful consideration will be needed to properly
1724 interpret multiple GM estimates (see Section 3.6.3).
1725
1726 Identical to the derivation of the SSM in the 1986 criteria document, the STV
1727 corresponds to an upper percentile (e.g., 75th percentile) of a water-quality distribution
1728 around the 2012 RWQC's GM. EPA is recommending the STV in the 2012 RWQC,
1729 rather than an SSM, to resolve previous inconsistencies in implementation and to ensure
6 For data points reported below detectable limits, the GM calculation should based on the assumption that
those observations were present at the detection limit.
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1730 that both components of the 2012 RWQC (i.e., the GM and STV) are equivalently
1731 stringent. Since FIB are highly variable in environmental waters and generally are well
1732 represented by a logic normal distribution (Bartram and Rees, 2000, Wyer et al., 1999,
1733 Kay et al., 2004), distributional estimates are more robust than single point estimates. In
1734 addition, EPA is no longer recommending multiple "use intensity" values to ensure
1735 equivalent public health protection in all waters. This section clarifies how a WQS that
1736 includes a GM and STV should be used and evaluated for various CWA purposes. EPA
1737 believes that in order to be consistent with EPA's recommended criteria; the criteria in a
1738 State WQS need to include both the GM and STV.
1739
1740 The STV represents the estimated 75th percentile of a distribution of water quality as
1741 measured by FIB. For the 2012 RWQC, EPA computed the STV based on the observed
1742 pooled variance of the FIB data reported in EPA's epidemiological studies. The
1743 computed pooled variances represent a wide range of weather conditions because the
1744 monitoring was conducted over the full course of the set of epidemiological studies. In
1745 computing the observed pooled variance, EPA stratified the data from the
1746 epidemiological studies by beach and water depth, since these are known to differ
1747 systematically in their respective distributions of FIB (Wade et al., 2008), and computed
1748 the variances within each of the resulting strata. The pooled variances from these 14
1749 subsets of the data in effect represent an overall mean variance. For the qPCR method,
1750 the pooled variance resulted in a log standard deviation (the standard deviation of the
1751 base 10 logarithms of the data) of 0.49 and the pooled variance estimates for culturable
1752 FIB that were reported previously (U.S. EPA, 1986). For the STV, EPA selected the
1753 estimated 75* percentile to align the beach notification decision-making process with the
1754 water-quality attainment criteria (i.e., the 1986 SSM was based on the estimated 75
1755 percentile and beach-management decisions were based on this value).
1756
1757 3.6.1 Use of the STV for Beach Notification
1758
1759 The estimated 75th percentile STV is the recommended value for beach notification
1760 purposes (such as advisories and closings). Any single sample above the estimated 75th
1761 percentile STV should trigger beach notification until another sample that is below the
1762 estimated 75* percentile STV is collected. Additionally, a short-term GM can be useful
1763 in the beach advisory context.
1764
1765 3.6.2 Criteria Magnitude, Duration, and Frequency for other CWA Purposes
1766
1767 o Magnitude: GM and the estimated 75th percentile STV regardless of the sample size.
1768 o Duration: For calculating the GM and associated STV, EPA recommends a duration
1769 between 30 days and 90 days. The duration for calculating the GM and associated
1770 STV should not exceed 90 days. The duration is a component of a water quality
1771 criterion and as such would need to be explicitly included in the State's WQS.
1772 Sampling of waterbodies should be representative of meteorological conditions (e.g.,
1773 wet and dry weather). If a State is not sampling during or immediately after a rain
1774 event, the State should advise the public to the risks of primary contact recreation.
1775 o Frequency of exceedance:
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1776 GM: The GM of a body of water over the duration specified in the standard for
1777 calculating a GM should not be higher than the recommended GM criteria value.
1778 Therefore, EPA recommends a frequency of exceedance of zero - i.e., no
1779 "excursions" - of the GM over the duration specified in the State standard. Like
1780 duration, the frequency of exceedance is a component of a water quality criterion and
1781 as such would need to be explicitly included in a State's WQS.
1782 STV: EPA recommends that no more than 25 percent of the observations exceed the
1783 STV over the duration specified for calculating the STV. This should be computed by
1784 multiplying the total number of observations by 0.25. The number of observations
1785 above the STV is the whole-number portion of this quotient.
1786
1787 A State's recreational WQS should include a clearly articulated magnitude, duration, and
1788 frequency. States may adopt more stringent criteria into their WQSs. For example, it may
1789 be appropriate for States to establish a lower frequency of exceedances of the STV based
1790 on regional or site-specific circumstances or studies.
1791
1792 NPDES permitting purposes
1793
1794 The NPDES regulations at 40 CFR 122.44(d) require the development of water quality-
1795 based effluent limitations (WQBELs) as necessary to attain water quality standards.
1796 Under §122.45(d), permit limits for continuous dischargers must include both short- and
1797 long-term WQBELs unless there is a specific finding of "impracticability." To derive the
1798 required short-term (maximum daily or average weekly) permit limits, EPA recommends
1799 that permitting authorities use the more stringent derivation values between the GM and
1800 STV. To derive the required long-term (average monthly) permit limits, EPA
1801 recommends that permitting authorities use the GM. Once established, pathogen limits
1802 for continuous dischargers are applied and enforced in a manner consistent with all other
1803 water quality parameters.
1804
1805 For non-continuous or episodic discharges, by comparison, 40 CFR 122.45(e) requires
1806 WQBELs to reflect the frequency of discharge; total mass; maximum discharge rate; and
1807 prohibition or limitation of specified pollutants by mass, concentration, or other measure.
1808 Combined sewer overflows (CSOs) are a key example of these types of discharges. As
1809 the paragraph below discusses, EPA's longstanding CSO Policy has recommended
1810 various approaches for addressing CSO discharges. The statistical framework underlying
1811 EPA's revised water quality criteria recommendations recognizes that a certain number
1812 of excursions from the STV criteria value may be permissible. Therefore, in permitting
1813 episodic discharges, such as CSOs, it may be appropriate for a permitting authority to
1814 authorize a limited number of discharge events that could exceed the STV as long as the
1815 permitting authority could demonstrate that the applicable criteria for primary contact
1816 uses (STV and geometric mean values) would be maintained in the stream. (As
1817 mentioned above, CSOs are episodic discharges that pose particular challenges for water
1818 quality-based permitting due to the extreme variability in the volume and quality of
1819 overflows. For this reason the 1994 CSO Control Policy (also see section 402(q) of the
1820 CWA) provides for expression of WQBELs as performance standards based on average
1821 design conditions (e.g., a maximum number of overflow events per year or a minimum
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1822 percentage capture of combined sewage). The CSO Policy also recommends WQS
1823 review and revision, as appropriate, to reflect the site-specific wet weather impacts of
1824 CSOs. This review should be coordinated with the development, implementation, and
1825 post-construction monitoring associated with an approved long-term CSO control plan.
1826 WQS review could involve a use attainability analysis (40 CFR 131.10(g)) and
1827 subsequent modification of a designated use - for example, adoption of a partial or time-
1828 limited use for a defined period of time when primary contact recreation does not exist.
1829
1830 Detailed approaches for deriving WQBELs to meet WQS based on EPA's final 2012
1831 RWQC will be further explained in the TSM.
1832
1833 Identification of Impaired and Threatened Waters
1834 Under §303(d) of the CWA and EPA's implementing regulations (40 CFR 130.7), states,
1835 territories, and authorized tribes (hereafter referred to as states) are required to develop
1836 lists of impaired and threatened waters that require Total Maximum Daily Loads
1837 (TMDLs). Impaired waters are those that do not meet any applicable WQS. EPA
1838 recommends that states consider as threatened those waters that are currently attaining
1839 WQS, but which are expected not to meet WQS by the next listing cycle (every two
1840 years). Consistent with EPA recommendation, many states consolidate their §303(d) and
1841 §305(b) reporting requirement into one "integrated" report.
1842
1843 For making these water quality attainment determinations, a State that adopts WQSs
1844 consistent with the 2012 RWQC, would evaluate all readily available data and
1845 information to determine whether a waterbody meets the WQS (i.e., whether the
1846 waterbody is in attainment). A WQS that is consistent with EPA's recommended criteria
1847 would include both a GM and an STV, and all three components of a WQS (e.g.,
1848 magnitude, duration, and frequency) for both the GM and the STV. Both the GM and the
1849 STV apply independently and would need to be evaluated to determine whether or not
1850 water quality in a given waterbody meets the WQS for primary contact recreation. The
1851 waterbody condition would need to be evaluated based on all existing and readily
1852 available data and information for the specified duration. EPA's regulations define "all
1853 existing and readily available water quality related data and information" at 40 CFR
1854 130.7(b)(5). EPA expects that water quality attainment determinations would include
1855 water quality monitoring data collected as part of a beach monitoring program, as well as
1856 information regarding beach closures and advisories.
1857
1858 3.6.3 Practical Considerations for Applying the Criteria
1859
1860 The number of samples is not an approvable element of a WQS, therefore states should
1861 not include a minimum sample size as part of their criteria submission. The
1862 recommendations and information provided in this section can be used when identifying
1863 sampling frequency as part of a state's monitoring plan.
1864
1865 Typically, a larger dataset will more accurately characterize the water quality in a
1866 waterbody, resulting in more meaningful attainment determinations (Table 3 and Figure
1867 5). Therefore, EPA is recommending that states conduct weekly sampling to calculate a
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1868 GM over a 30 to 90 day period. This recommendation is consistent with global
1869 recommendations for recreational water management (WHO, 2003; E.U. 2007; MFE
1870 2003). EPA's analysis indicates increasing the number of samples when calculating a
1871 GM from the typical monthly regime of 4 or 5 samples to the recommended 90 day basis
1872 of 12 to 15 samples will reduce waterbody misclassification from both Type I (false
1873 positive) and Type II (false negative) errors with respect to attainment status based on the
1874 computed GM (Table 3 and Figure 5). For example, compared to GMs based on four
1875 samples (logsd=0.7), the predicted level of waterbody misclassification for 15 samples is
1876 reduced by 50 percent for a simulated waterbody with GM of 30 cfu per 100 mL (from
1877 34 percent to 17 percent) and 98 percent for a simulated waterbody with GM of 60 cfu
1878 per 100 mL (from 10 percent to 0.2 percent). Although waterbody misclassification can
1879 occur even with large datasets (e.g., 60 samples or more), the likelihood of waterbody
1880 misclassification is highest when the GM is based on a small number of samples (Figure
1881 5).
1882
1883
1884
43
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1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
Table 3. Sample size influences the likelihood of misclassification.1
Number of
Samples
4
5
12
15
Actual Geometric Mean
(cfu enterococci per 100 ml)
25
20.3%
14.0%
5.3%
3.4%
30
34.6%
31.0%
22.0%
17.4%
45
25.0%
21.1%
9.7%
8.6%
60
10.0%
4.0%
0.2%
0.2%
falsely being determined as above or below the limit (35 GM), when in fact the true GM is below
(GM=25 and 30) or above (GM=45 and 60).
2 Actual GM is the GM of a simulated waterbody (with logsd=0.7).
Actual GM 25 cfu/lOOmL
Actual GM 30 cfu/lOOmL
Actual GM 45cfu/100mL
Actual GM 60 cfu/lOQmL
20
30 40
Sample size
70
1901
1902
1903
1904
1905
1906
1907
1908
Figure 5. Likelihood of misclassification as a function of sample size.
(Graphical representation of data in Table 3)
44
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1909 4.0 Recreational Water Quality Criteria
1910
1911 EPA evaluated the available data and determined that the designated use of recreation
1912 would be protected if the following criteria were adopted into State WQS:
1913
1914 (a) Fresh water criteria
1915 Magnitude: Culturable E. coli at a GM of 126 cfu per 100 mL and an STV of
1916 235 cfu per 100 mL measured using EPA Method 1603, or any other
1917 equivalent method that measures culturable E. coli; culturable enterococci at a
1918 GM of 33 cfu per 100 mL and an STV of 61 cfu per 100 mL measured using
1919 EPA Method 1600 (U.S. EPA, 2002b), or any other equivalent method that
1920 measures culturable enterococci; or both of the above criteria. EPA believes
1921 that in order to be consistent with EPA's recommended criteria, the criteria in
1922 a State WQS need to include both the GM and STV.
1923
1924 Duration: For calculating the GM and associated STV, EPA recommends a
1925 duration between 30 days and 90 days. The duration for calculating the GM
1926 and associated STV should not exceed 90 days. The duration is a component
1927 of a water quality criterion, and as such, would need to be explicitly included
1928 in the State's WQS. Sampling of waterbodies should be representative of
1929 meteorological conditions (e.g., wet and dry weather). If a State is not
1930 sampling during or immediately after a rain event, the State should advise the
1931 public to the risks of primary contact recreation.
1932
1933 Frequency: EPA recommends a frequency of zero exceedances of the GM and
1934 < 25 percent exceedance of the STV, over the duration specified for
1935 calculating the GM and STV. The frequency of exceedance is a component of
1936 a water quality criterion, and as such, would need to be explicitly included in
1937 State's WQS.
1938
1939 (b) Marine criteria
1940 Magnitude: Culturable enterococci at a GM of 35 cfu per 100 mL and an STV
1941 of 104 cfu per 100 mL measured using EPA Method 1600, or any other
1942 equivalent method that measures culturable enterococci. EPA believes that in
1943 order to be consistent with EPA's recommended criteria, the criteria in a State
1944 WQS need to include both the GM and STV.
1945
1946 Duration: For calculating the GM and associated STV, EPA recommends a
1947 duration between 30 days and 90 days. The duration for calculating the GM
1948 and the associated STV should not exceed 90 days. The duration is a
1949 component of a water quality criterion, and as such, would need to be
1950 explicitly included in the State's WQS. Sampling of waterbodies should be
1951 representative of meteorological conditions (e.g., wet and dry weather). If a
1952 State is not sampling during or immediately after a rain event, the State should
1953 advise the public to the risks of primary contact recreation.
1954
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1955 Frequency: EPA recommends a frequency of zero exceedances of the GM and
1956 < 25 percent exceedance of the STV, over the duration specified for
1957 calculating the GM and STV. The frequency of exceedance is a component of
1958 a water quality criterion, and as such, would need to be explicitly included in
1959 State's WQS.
1960
1961 EPA has also developed a qPCR method to detect and quantify enterococci more rapidly
1962 than the culture method. Enterococci as measured by EPA Enterococcus qPCR method A
1963 has shown a strong relationship to GI illness in the recent EPA NEEAR epidemiological
1964 studies compared to other methods tested (Wade et al., 2008; U.S. EPA, 2010d).
1965 Introduction of EPA Enterococcus qPCR method A is anticipated also to provide
1966 increased public health protection by permitting timely notification7 to swimmers of
1967 levels of FIB that exceed the site-specific criteria value. While the fresh water Great
1968 Lakes and temperate marine water NEEAR studies resulted in minimal to no inhibition, it
1969 is EPA's goal to publish RWQC recommendations that can be recommended nationally.
1970 Given the current state of knowledge regarding the performance of qPCR methods under
1971 varied waterbody conditions and the limited experience of its use in the field, EPA
1972 encourages a site-specific assessment of the method's performance before it is adopted
1973 into State WQS for implementation in beach monitoring programs.
1974
1975 For the purposes of beach monitoring, alternative site-specific criteria could be adopted
1976 into State standards measured by EPA's Enterococcus qPCR method A based on a site-
1977 specific performance characterization. This method is not recommended for NPDES
1978 permitting. A "site" may be a beach, a waterbody, or a particular watershed that is
1979 anticipated to have uniform qualities throughout. As States adopt water-quality standards
1980 for enterococci, as measured by EP A's Enterococcus qPCR method A, they will gain
1981 experience with the qPCR method and better understand how this method performs in
1982 their waters. Considerations for determining how qPCR could be used to develop site-
1983 specific criteria will be provided in additional TSM. For States interested in adopting a
1984 value for enterococci using EPA's Enterococcus qPCR method A into their WQS, EPA
1985 recommends a GM criterion of 475 CCE per 100 mL and an STV criterion of 1,000 CCE
1986 per 100 mL in freshwaters and marine waters based on its epidemiological study data.
1987
1988 Because this document only includes supplementary information about how States may
1989 adopt water-quality standards on a site-specific basis for enterococci as measured by
1990 qPCR, the 2012 RWQC recommendations are not "applicable" to that pathogen indicator
1991 (i.e., enterococci as measured by qPCR). Therefore, the inclusion of qPCR-related
1992 information in this document does not trigger the requirement in CWA §303(i) that States
1993 adopt water-quality standards "for all pathogens and pathogen indicators to which the
1994 new or revised WQC are applicable" for their coastal recreational waters.
See section 5.2.1 for a discussion on the use of predictive models as an additional approach for achieving
timely notification.
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1995 5.0 Tools to Support States and Tribes in Managing Recreational Waters and for
1996 Considering Alternate Water Quality Criteria
1997
1998 EPA's implementing regulations for §303 of the CWA provide that "states must adopt
1999 those WQC that protect the designated use. Such criteria must be based on sound
2000 scientific rationale and must contain sufficient parameters or constituents to protect the
2001 designated use." (40 CFR §131.11(a)). EPA's regulations stated in 40 CFR §131.11(b)(l)
2002 provide that "In establishing criteria, States should (1) Establish numerical values based
2003 on (i) 304(a) Guidance; or (ii) 304(a) Guidance modified to reflect site-specific
2004 conditions; or (iii) Other scientifically defensible methods." WQS can be established for
2005 waterbodies, or a portion of a water body and therefore they could be established for a
2006 specific site, such as a waterbody adjacent to a beach or the entire water body that is
2007 anticipated to have uniform qualities throughout. When EPA reviews State WQSs for
2008 approval or disapproval under the CWA, EPA must ensure that the WQC in the standard
2009 (regardless of whether they are "site-specific") are scientifically defensible and protective
2010 of the designated use.
2011
2012 The tools discussed in this section fall into two main categories: (1) tools that States can
2013 use to enhance public health protection when implementing state WQS for primary
2014 contact recreation; and (2) tools that can be used by States in the development of WQC
2015 that differs from EPA's recommended criteria ("alternate criteria"). Alternate criteria
2016 could be developed to reflect site-specific conditions, or they could be developed using
2017 different indicators and analytical methods. State WQS that include alternate criteria
2018 would need to be scientifically defensible and protective of the use. These tools reflect
2019 currently available scientific information, can be utilized to assist in the assessment and
2020 management of recreational waters (see section 5.1), and have the potential to be used in
2021 the development of site-specific criteria (see section 5.2). Site-specific criteria are based
2022 in part on assumptions regarding the current state of a watershed such as current land
2023 uses, and should be revisited no less frequently than triennially to ensure the site-specific
2024 criteria remains protective of the primary contact recreation use. This section does not
2025 provide details on how to implement these tools. Additional, detailed information on
2026 these tools will be provided in TSM.
2027
2028 The tools discussed below (and the corresponding subsections) are (1) sanitary surveys
2029 (5.1.1); (2) predictive models (5.1.2); (3) epidemiological studies (5.2.1); (4) quantitative
2030 microbial risk assessment (QMRA) (5.2.2); and (5) approaches for developing criteria
2031 using alternative fecal indicators and/or methods (5.2.3).
2032
2033 5.1 Tools for Assessing and Managing Recreational Waters
2034
2035 EPA recognizes that advancements have been made since the publication of the 1986
2036 criteria in the area of managing recreational waters. This section discusses tools that
2037 States can use to enhance public health protection. These tools can aid in the
2038 identification of days of poor water quality on a site-specific basis. Specifically, this
2039 section discusses the use of sanitary surveys as a tool for identifying sources of fecal
2040 contamination and identifying and prioritizing clean-up/remediation actions for a specific
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2041 body of water and the use of predictive models for timely beach notification. EPA
2042 encourages the use of sanitary surveys and predictive models, specifically by beach
2043 managers, to better understand and potentially control sources of fecal contamination and
2044 pathogens. EPA also encourages the use of predictive models to supplement a sound
2045 monitoring program that has the potential to prevent human exposure on days of poor
2046 water quality. Together, the tools in this section have the potential to allow a State or
2047 locality to assess and communicate the risks associated with fecally contaminated
2048 recreational waters. These tools are not a part of the adopted WQSs and do not result in
2049 different numerical criteria value(s).
2050
2051 5.1.1 Sanitary Survey
2052
2053 Beach managers often use sanitary surveys to assess beaches for fecal contamination and
2054 to prioritize clean-up and remediation efforts. Beach sanitary surveys involve collecting
2055 information at the beach, as well as in the surrounding watershed. Information collected
2056 at the beach may include the following: proximity to septic systems, number of birds at
2057 the beach, slope of the beach, location and condition of bathrooms at beach facilities, and
2058 amount of algae on the beach. Information collected in the watershed may include the
2059 following: land use, location of storm water outfalls, surface water quality, and
2060 residential septic tank information.
2061
2062 Sanitary surveys are a "snapshot" of the conditions at a beach, which can change due to
2063 factors including those listed above. Sanitary surveys help State and local beach program
2064 managers and public health officials identify sources of beach water pollution, assess the
2065 magnitude of pollution, and designate priority locations for water testing. In conjunction
2066 with monitoring to determine whether a waterbody is meeting State WQS for recreation,
2067 they can use sanitary survey data (such as bacteria levels, source flow, turbidity, and
2068 rainfall) to develop models to predict bathing beach water quality using readily available
2069 data. Other information, such as source tracking and watershed information may be
2070 needed to effectively delineate sources within the watershed.
2071
2072 EPA has developed documents on sanitary surveys for the purpose of supplementing the
2073 2012 RWQC recommendations. These documents are available on the website:
2074 http://water.epa.gov/type/oceb/beaches/sanitarysurvey_index.cfm, as well as in Great
2075 Lakes Beach Sanitary Survey User Manual (U. S. EPA, 2008). EPA plans to include
2076 detailed information on developing and using sanitary surveys in its upcoming beach
2077 guidance and other TSM (see Appendix D).
2078
2079 5.1.2 Predictive Models
2080
2081 EPA recognizes that, at some locations and under some conditions, implementation of a
2082 rapid enumeration methodology, such as the qPCR-based method described previously in
2083 this document, is not feasible or is unlikely to provide sufficiently timely information for
2084 making a same-day beach notification decision (for example, in locations where water
2085 samples cannot be transported to the appropriate laboratory facilities for analysis in a
2086 timely manner). EPA is therefore providing an approach that may supplement the current
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2087 culture-based analytical results to facilitate same-day public health decisions. EPA
2088 encourages the use of predictive models in these situations to allow timely notification at
2089 beaches. Typically, States would use these and site-specific predictive models, such as
2090 statistical models, rainfall threshold levels, and notification protocols (U.S. EPA, 2010b,
2091 2010c), to supplement monitoring using culture-based methods. The models would not
2092 themselves be a part of State' WQS.
2093
2094 Predictive models that are currently employed in areas such as the Great Lakes have
2095 proven to be effective. These models draw on existing culture-based monitoring data
2096 bases, are inexpensive to use, and allow for a rapid, proactive beach management
2097 decisions (U.S. EPA, 2010b,c). They provide a means to supplement monitoring and
2098 support rapid notification.
2099
2100 EPA has conducted research and published a two-volume report to advance the use of
2101 predictive models (U.S. EPA, 2010b,c). Volume I summarizes the current uses of these
2102 predictive tools to provide model developers with the basic concepts for developing
2103 predictive tools for same-day beach notifications at coastal marine waters, the Great
2104 Lakes, and inland waters (U.S. EPA, 2010b). Volume II provides the results of research
2105 conducted by EPA on developing statistical models at research sites. It also presents
2106 Virtual Beach, a software package designed to build statistical multivariate linear
2107 regression predictive models (U.S. EPA, 2010c; see Appendix D). EPA is also expanding
2108 the Virtual Beach tool so that it will include other statistical approaches besides multiple
2109 linear regression. Techniques such as recursive partitioning (especially a technique called
2110 the Gradient Boosting Method [GBM] that involves usage of multiple decision trees) are
2111 promising. Artificial neural networks, binary logistic regression, and partial least-squares
2112 techniques also are being added. Beyond these improvements in Virtual Beach, other
2113 efforts such as linking watershed and statistical models, Cyterski's temporal
2114 synchronization approach to incorporate time lags, and process-based transformations are
2115 being pursued to improve predictive modeling efforts.
2116
2117 The types of predictive tools that can be used to make beach notification decisions fall
2118 into the following categories: statistical regression models, rainfall-based notifications,
2119 decision trees or notification protocols, deterministic models, and combinations of tools.
2120
2121 • A statistical regression model is a general term for any type of statistical modeling
2122 approach used to predict beach water quality. A statistical correlation (for
2123 example, one established using multivariate linear regression techniques) is
2124 observed between FIB and environmental and water quality variables that are
2125 easier to measure than FIB. Typical variables include meteorological conditions
2126 (such as solar radiation, air temperature, precipitation, wind speed and direction,
2127 and dew point), water quality (such as turbidity, pH, conductivity/salinity, and
2128 ultraviolet [UV]/visible spectra), and hydrodynamic conditions (such as flows of
2129 nearby tributaries, magnitude and direction of water currents, wave height, and
2130 tidal stage).
2131 • Rainfall-based notifications are based on a rain threshold level, which is a
2132 predictive tool that can be used when a connection exists between the
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2133 concentration of FIB at a beach and the amount of rain received in nearby areas.
2134 That relationship can be quantified as the amount or intensity of rainfall (i.e., the
2135 threshold level) that is likely to cause an exceedance of the WQSs at a beach, and
2136 the length of time over which the standards will be exceeded.
2137 • Decision trees or notification protocols are a series of questions that can also be
2138 used to consider factors such as rainfall to guide beach notifications. Such
2139 evaluations use water quality sampling, rainfall data, and other environmental
2140 factors that could influence FIB levels (such as proximity to pollution sources,
2141 wind direction, visual observations, or other information specific to the region or
2142 beach). This process is referred to as developing a notification protocol.
2143 • Deterministic models use mathematical representations of the processes that
2144 affect bacteria densities to predict exceedances of WQSs. They include a range of
2145 simple to complex modeling techniques.
2146
2147 There are various considerations for developing each of these model types for beaches
2148 and each has its own set of challenges (Boehm et al., 2007). To be effective, these
2149 predictive models should be sufficiently calibrated to reflect site-specific conditions and
2150 account for inter-seasonal variations, if applicable. Predictive models are intended for use
2151 as a rapid beach notification tool only. They do not replace the need for a sound
2152 monitoring program, and the development of predictive models requires monitoring data
2153 both for establishing and maintaining statistical relevance. A State using a site-specific
2154 predictive model would still need to evaluate the waterbody in order to determine
2155 whether it meets the WQS for purposes of CWA §303(d) listing.
2156
2157 5.2 Tools for Use in Developing Alternative Criteria
2158
2159 As described above, EPA's regulations provide that "States must adopt those water
2160 quality criteria that protect the designated use. Such criteria must be based on sound
2161 scientific rationale and must contain sufficient parameters or constituents to protect the
2162 designated use." 40 CFR 131.1 l(a). EPA's regulations at 40 CFR §131.1 l(b)(l) provide
2163 that in establishing criteria, States should (1) establish numerical criteria based on (i)
2164 EPA's CWA §304(a) guidance; (ii) §304(a) guidance modified to reflect site-specific
2165 conditions or, (iii) other scientifically defensible methods. States could adopt site-specific
2166 modifications of a §304(a) criterion to reflect local environmental conditions and human
2167 exposure patterns. A "site" may signify beach, a waterbody, or a particular watershed,
2168 that is anticipated to have uniform qualities throughout. Such site-specific criteria may be
2169 adopted into a state WQS as long as the resulting site-specific WQS are scientifically
2170 defensible and protective of the use. For example, alternative WQSs may involve the
2171 adoption of different numerical value(s) that are based on: (1) the results of an
2172 epidemiological study; (2) the results of a quantitative QMRA to account for different
2173 sources of FIB; or (3) a different FIB-method combination. To be used for CWA
2174 purposes, site-specific criteria would need to be adopted into State WQS and reviewed
2175 and approved under CWA §303(c).
2176
2177 EPA believes that the recommended 2012 RWQC, which are derived from and informed
2178 by the preponderance of epidemiological evidence in human fecal-impacted waters,
50
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2179 would be protective of primary contact recreation. EPA recognizes, however, that the
2180 conditions studied in the temperate fresh waters and marine waters by the NEEAR
2181 studies (i.e., waters primarily impacted by secondary-treated and disinfected POTW
2182 effluent) may not be representative of all possible fecal contamination combinations that
2183 could impact recreational bodies of water in the United States. Therefore, this section
2184 describes the tools available to support States considering alternate WQS based on other
2185 data such as: (1) epidemiological studies, (2) QMRA, and (3) novel fecal indicators and
2186 analytical methods.
2187
2188 5.2.1 Epidemiological Studies
2189
2190 EPA's NEEAR epidemiological studies were conducted in water primarily impacted
2191 human fecal contamination, including temperate fresh water, temperate marine water, and
2192 tropical marine water sites, as well as one temperate marine water site that was impacted
2193 by urban runoff (Wade et al., 2006, 2008, 2010; U.S. EPA, 2010d). Statistically
2194 significant associations between water quality, as determined using Enterococcus
2195 measured by qPCR, and reported illness were observed in the temperate marine water and
2196 fresh water POTW-impacted beaches. No associations between FIB, enumerated with
2197 either culture-based or qPCR-based methods, and reported illness were observed at the
2198 beach impacted by urban runoff in Surfside, SC or at the tropical beach in Boqueron, PR.
2199
2200 Local and/or State agencies have conducted, or are considering conducting,
2201 epidemiological studies of health risks and water quality at recreational beach sites. For
2202 example, epidemiology studies of recreational water exposures have been conducted
2203 recently in Southern California (SCCWRP,personal communication, 2010), south Florida
2204 (Fleming, 2006; Sinigalliano, 2010), and Ohio (Marion et al., 2010). These studies could
2205 be used to confirm EPA's 2012 criteria or to develop site-specific criteria.
2206
2207 Several factors can influence the potential epidemiological relationship between indicator
2208 density and relative human health risk. Some of the potentially important factors include
2209 the source of fecal contamination, age of the fecal contamination, intensity of solar
2210 radiation that the fecal contamination is exposed to, water salinity, turbidity, dissolved
2211 organic matter, water temperature, and nutrient content. Numerous factors also affect the
2212 occurrence and distribution of FIB and the pathogens from the source of contamination to
2213 the receptor location that include, but are not limited to, the following: predation of
2214 bacteria by other organisms; differential interactions between microbes and sediment,
2215 including the release and resuspension of bacteria from sediments in the water column;
2216 and differential environmental effects on indicator organisms versus pathogens. For
2217 additional information, see Appendix B.
2218
2219 States or local agencies may choose to conduct epidemiological studies in their
2220 waterbodies and use the results from those studies to derive site-specific criteria. To
2221 derive scientifically defensible site-specific WQC for adoption into state standards, the
2222 epidemiological studies should be of similar quality and of comparable scientific rigor as
2223 EPA's NEEAR water studies. The epidemiological information underlying the
2224 recommended 2012 RWQC was produced using a study design called "prospective
51
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2225 cohort." EPA is unsure at the current time how results from alternate epidemiological
2226 study designs can inform site-specific criteria. Significant differences in the study
2227 designs, data collection, and analysis methods, exposure, and health outcome measures
2228 pose a major challenge to the ability to quantitatively compare the illness rate and water
2229 quality relationships in epidemiological studies with significant design differences to the
2230 NEEAR studies.
2231
2232 Epidemiological studies are resource intensive and logistically difficult, although the
2233 results can provide the data necessary for a scientifically defensible basis to allow the
2234 adoption of WQS based on fecal indicator/methods that are not part of EPA's national
2235 §304(a) recommendations. First, site-specific epidemiological studies can take into
2236 account the characteristics of local waterbodies to support the derivation of a site-specific
2237 criteria value based on the fecal indicator/methods that are part of EPA's national §304(a)
2238 recommendations. Second, such studies may support the development and adoption of
2239 alternative criteria based on different health endpoints, such as respiratory illnesses, than
2240 EPA has used in its current recommendations (i.e., GI illnesses). Where the studies
2241 demonstrate a statistically significant correlation between levels of water quality
2242 measured using particular Fffi(s) and adverse health outcomes, they may be scientifically
2243 defensible and as such, could be used to develop and adopt alternate criteria.
2244
2245 If a State wishes to develop alternative criteria using their own epidemiological studies,
2246 EPA recommends that the studies also be of the PC design, to facilitate the evaluation of
2247 the resultant alternative criteria. EPA's TSM will provide additional information on the
2248 use of epidemiological studies in development of site-specific criteria.
2249
2250 5.2.2 Quantitative Microbial Risk Assessment and Sanitary Characterization
2251
2252 If a particular waterbody is believed to be predominantly impacted by nonhuman sources,
2253 a site-specific criterion may be worth investigating. EPA's research indicates that
2254 understanding the predominant source of fecal contamination is critical for
2255 characterization of the human health risks associated with recreational water exposure.
2256 Various epidemiological investigations, including EPA's have documented human health
2257 effects in waters impacted by human fecal contamination. Additionally, QMRA studies
2258 have demonstrated that the potential human health risks from human and non-human
2259 fecal sources can be different due to the nature of the source, the type and number of
2260 pathogens from any given source, as well as, variations in the co-occurrence of pathogens
2261 and fecal indicators associated with different sources (Till and McBride, 2004, Roser et
2262 al, 2006, Schoen and Ashbolt, 2010, Seller et al., 2010b, Bambic et al, 2011). While
2263 human sources of fecal contamination pose similar health risks regardless of location, the
2264 differences in predicted human health risks from recreational water exposure to non-
2265 human fecal contamination are dependent on local characteristics that will vary from site-
2266 to-site. EPA is not recommending nationally-applicable criteria values for recreational
2267 waters that account for non-human sources of fecal contamination due to this variability.
2268 EPA's nationally applicable criteria values can be used for such waters. However, EPA is
2269 making available TSMs for QMRA to assist States in developing equivalent site-specific
2270 criteria to account for local scale, non-human sources.
52
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2271
2272 Any alternative WQSs must be scientifically defensible and protective of the use. QMRA
2273 is one tool that has been identified as potentially useful for developing alternative criteria
2274 by enhancing the interpretation and application of new or existing epidemiological data
2275 (Boehm et al., 2009; Dorevitch et al., 2011). Recreational water epidemiological studies
2276 describe the risks associated with exposure to fecal contamination as measured by FIB.
2277 QMRA can supplement new or existing epidemiological results by characterizing various
2278 exposure scenarios, interpreting potential etiological drivers for the observed
2279 epidemiological results, and accounting for differences in risks posed by various types of
2280 fecal sources. EPA is working to anchor the QMRA framework to existing
2281 epidemiological relationships as part of the TSMs.
2282
2283 QMRA applies risk-assessment principles (NRC, 1983) to approximate the consequences
2284 from exposure to selected infectious pathogens. To the greatest possible extent, the
2285 QMRA process includes the evaluation and consideration of quantitative information;
2286 qualitative information, however, is also used when appropriate (WHO, 1999). QMRA
2287 can be initiated for a variety of reasons, including, but not limited to, the following:
2288
2289 • to assess the potential for human risk associated with exposure to a known
2290 pathogen;
2291 • to determine critical points for control, such as watershed protection measures;
2292 • to determine specific treatment processes to reduce, remove, or inactivate various
2293 pathogens;
2294 • to predict the consequences of various management options for reducing risk;
2295 • to determine appropriate criteria (regulatory) levels that will protect individuals
2296 and/or populations to a specified risk level or range
2297 • to identify and prioritize research needs; and
2298 • to assist in interpretation of epidemiological investigations.
2299
2300 QMRA methodologies have been applied to evaluate and manage pathogen risks for a
2301 range of scenarios, including from food, sludge/biosolids, drinking water, recycled water,
2302 and recreational waters. Moreover, risk assessment in general has been used extensively
2303 by EPA for decades to establish human health criteria for a wide range of pollutants in
2304 water and other media, and microbial risk assessment has been used to inform EPA's
2305 policy making for microbiological pollutants in drinking water and biosolids, and by
2306 other U.S. and international governmental agencies (e.g., U.S. Department of Agriculture
2307 [USDA], U.S. Food and Drug Administration, WHO) to protect public health from
2308 exposure to microbiological pollutants in food and water.
2309
2310 For recreational waters, QMRA incorporates a site-specific sanitary characterization and
2311 maybe used to determine if a particular waterbody/watershed is predominantly impacted
2312 by a source other than human fecal contamination and whether lower relative risk is
2313 associated with the contributing source(s) of fecal contamination in that waterbody or
2314 watershed (Seller et al., 2010a,b). Site characterization tools (similar to an enhanced
2315 sanitary survey) can provide detailed information on the source(s) of fecal contamination
2316 in a waterbody and whether the sources are human or nonhuman. EPA developed a
53
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2317 QMRA-specific application of the sanitary survey, hereafter referred to as a site
2318 characterization, to capture information directly applicable for the conduct of a QMRA.
2319 This site-specific sanitary characterization process will be described in detail in the
2320 QMRA TSM.
2321
2322 Where sanitary site characterization work indicates that the predominant source is human,
2323 the 2012 RWQC recommendations are scientifically defensible and protective of primary
2324 contact recreation. Also, when sources are predominately nonhuman, EPA has concluded
2325 the 2012 RWQC would be scientifically defensible and protective of primary contact
2326 recreation. Where the sources of fecal contamination are predominantly nonhuman or
2327 non fecal, QMRA is a tool that is less resource intensive and more broadly applicable
2328 than epidemiological studies. Epidemiological studies have reported ambiguous results
2329 in scenarios impacted by nonhuman sources and are impractical in infrequently used
2330 waterbodies. However, EPA's QMRA framework, anchored with the newer reported
2331 epidemiological relationships, will help facilitate the risk characterization on a site-
2332 specific basis.
2333
2334 EPA's recent QMRA research provides new information on fecal contamination from
2335 nonhuman sources which, under some circumstances, may be less risky to human health
2336 than contamination from human sources (Schoen and Ashbolt, 2010; Seller et al.,
2337 2010a,b; U.S. EPA, 2010a). For additional information and case studies of QMRA for
2338 recreational waters, see Appendix C. This research demonstrates that different pathogens
2339 are expected to cause illness in recreational waters impacted by different sources of fecal
2340 contamination. For example, in human-impacted recreational waters, human enteric
2341 viruses are expected to cause a large proportion of illnesses (Seller et al., 2010a). In
2342 recreational waters impacted by gulls and agricultural animals, such as cattle, pigs, and
2343 chickens, other pathogens (such as bacteria and protozoa) would be expected to be the
2344 etiologic agents that cause human illness (Roser et al., 2006, Seller et al., 2010b; Schoen
2345 and Ashbolt, 2010). Other research also supports the utility of QMRA, such as QMRA
2346 conducted for a tropical waterbody (Viau et al., 2011) and the use of QMRA to establish
2347 recreational WQC in New Zealand (MFE, 2003).
2348
2349 Moreover, the relative level of predicted human illness in recreational waters impacted by
2350 nonhuman sources can vary depending on whether the contamination is direct or via
2351 runoff due to a storm event (U.S. EPA, 2010a). For example, when considering a direct
2352 contamination scenario in which FIB was assumed to be present at the 1986 criteria
2353 levels, predicted GI illness risks associated with exposure to recreational waters impacted
2354 by fresh cattle feces were not substantially different from waters impacted by human
2355 sources (Seller et al., 2010b). Predicted illness levels in bodies of water that contain FIB
2356 at the 1986 criteria levels from land-applied fecal material from cattle (with microbial
2357 loading due to runoff from a storm event), however, were approximately 20 times lower
2358 than the risk associated with human-impacted water (U.S. EPA, 2010a). These results
2359 highlight the potential power of QMRA to inform site-specific criteria.
2360
2361 To derive site-specific criteria that are considered scientifically defensible and protective
2362 of the use, QMRA studies should follow accepted practices, rely on scientifically
54
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2363 defensible data, and be well documented (Haas et al., 1999; Seller et al., 2004; Schoen
2364 and Ashbolt, 2010; MFE, 2003). EPA plans to provide additional guidance on conducting
2365 QMRA for the purpose of assessing differences in risk and for the possible derivation of
2366 site-specific criteria in a TSM.
2367
2368 5.2.3 Developing Alternative Criteria Based on Novel Indicators or New Analytical
2369 Methods, without Site-Specific Epidemiological Studies
2370
2371 EPA anticipates that scientific advancements will provide new technologies for
2372 quantifying fecal pathogens or fecal contamination indicators. These newer technologies
2373 may provide alternative ways to address methodological considerations, such as rapidity,
2374 sensitivity and specificity, and method performance in site-specific situations, but may
2375 not be appropriate for all CWA purposes. As new or alternative indicator and/or
2376 enumeration method combinations are developed, States may want to consider using
2377 them to develop WQC on a site-specific basis. EPA would approve them if the resulting
2378 criteria are scientifically defensible and protective of the recreational use. One way such
2379 alternate criteria may be demonstrated to be scientifically defensible would be a
2380 consistent and predictable demonstration of the enumeration method performance for a
2381 proposed site-specific criterion.
2382
2383 Previously, EPA has used the relative performance of enumeration methods to describe a
2384 common level of water quality. For example, derivation of the 1986 criteria was
2385 fundamentally based on the comparison of enumeration methods for FC, enterococci, and
2386 E. coli. In that specific case, those comparisons were made among membrane filtration
2387 methods specific to each target organism. Another example of this occurred when EPA
2388 approved the use of the IDEXX-based methods for the detection of enterococci and
2389 E. coli. In this comparison, results from a membrane-filtration method were compared to
2390 another method that relied on substrate-utilization and MPN enumeration. Use of already
2391 available rapid methods, such as qPCR methods for E. coli, has been demonstrated
2392 (Lavender and Kinzelman, 2009), on a site-specific basis.
2393
2394 Examples of other reported methodologies for quantifying of FIB include the following:
2395 immunomagnetic separation/adenosine triphosphate (IMS/ATP), propidium monoazide
2396 (PMA) qPCR, reverse transcriptase (RT) PCR, covalently linked immunomagnetic
2397 separation/adenosine triphosphate (COV-EVIS-ATP), and transcription mediated
2398 amplification (TMA-RNA)
2399
2400 Also, additional indicator organisms can be used with existing methodologies similar to
2401 those recommended by the 2012 RWQC. Examples of possible alternative indicators
2402 include but are not limited to, Bacteroidales, Clostridiumperfringens, human enteric
2403 viruses, and coliphages. For example, in one case, Bacteroidales measured by qPCR were
2404 highly correlated with Enterococcus and E. coli when either traditional, cultivation
2405 dependent, or qPCR methods were used (WERF, 2011). Norovirus GI and Gil have also
2406 shown to be predictors of the presence of other pathogens like Adenovirus, Giardia, and
2407 Cryptosporidium measured by qPCR (WERF, 2011). E. coli and Enterococcus measured
2408 by qPCR may also be a possible indicator and method in fresh water. For organism and
55
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2409 enumeration methodology combinations that are different from the 2012 RWQC, EPA
2410 would review technical information on incorporating alternative indicator organisms and
2411 enumeration methods provided by the State.
2412
2413 To facilitate consideration, States could gather water quality data over a recreational
2414 season for both an EPA-approved method and the proposed alternative indicator-method
2415 combination. A robust relationship need not necessarily be established between EPA's
2416 recommendation and alternative indicator(s) for the whole range of indicator densities
2417 observed, as EPA's recent research highlights these difficulties and limitations (U.S.
2418 EPA, 2010e). It is, however, important that a consistent and predictable relationship exist
2419 between the enumeration methods and an established indicator-health relationship in the
2420 range of the criteria. A State WQS using a different indicator or analytical method would
2421 need to be scientifically defensible and protective of the primary contact recreational use.
2422 Information on demonstrating the relationship between two-indicator method
2423 combinations can be found in TSM.
2424
56
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