IEPA ATTACHMENT NO.

United States

Environmental Protection

Agency

Office of Water

?

EPA440/5-84-002

Regulations and Standards

?

January 1986

Criteria and Standards Division

Washington, DC 20460

Water

a

EPA?

Ambient

Water Quality

Criteria for

Bacteria - 1986

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Click here for

DISCLAIMER

Document starts on next page

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3acteriological Ambient Water Quality Criteria

for Marine and Fresh Recreational Waters

U.S. Environmental Protection Agency

Office of Research and Development Office of Water Regulations

Microbiology and Toxicology Div.

?

and

Standards

Cincinnati, Ohio

?

Criteria and Standards Div.

Washington, D.C.

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CONTENTS

Page

Foreword

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ii i

Acknowledgements

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iv

Introduction

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1

St.idy Design

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3

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Data Base for Marine and Fresh Water

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4

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Basis of Criteria for Marine and Fresh Water ? 5 ?

Recommendation on Bacterial Criteria Monitoring

? 7 ?

Development of Recommended

Criteria Based on

E. coli

and enterococci ?

8

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Limitations and

Extrapolations of Criteria

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10

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Relationship With the Criteria Contained In Quality

Criteria

for

Water ?

10

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Tables

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12-15

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National Criteria

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16

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References

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17

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i

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DISCLAIMER

This report has been reviewed by the Criteria and Standards

Division, Office

of

Water Regulations and Standards, U.S. Environ-

mental Protection Agency, and approved for publication. Mention

of trade names or commercial products does not constitute endorse-

ment or recommendation for use.

AVAILABILITY NOTICE

This document is available to

the public through

the National

Technical Information

Service (NTIS), 5285 Port Royal Road,

Springfield, VA 22161. NTIS Access Number is PB 86-158045.

ii

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FOREWORD

Section 304(a)(1) of the Clean Water Act of 1977 (P.L. 95-217)

requires the Administrator of the Environmental Protection Agency

to

publish criteria for water quality accurately reflecting the

latest scientific knowledge on the kind and extent of all identi-

fiable effects on health and welfare which may be expected from

the presence of pollutants in any body of water, including ground

water. This document is a revision of proposed criteria based

upon a consideration of comments received fr_m other Federal

agencies, State agencies, special interest groups, and indiviud3l

scientists. The criteria contained in this document supple7ents

previously published EPA bacteriological criteria in Quality

Criteria for Water (1976).

The term "water quality criteria" is used in twee sections

of the Clean Water Act, section 304(a)(1) and Section 303(c)(2).

The term has a different program impact in each section. In

section 304, the term represents a non-regulatory, scientific

assessment of ecological and public health effects. The criteria

presented

in

this publication are such scientific assessments.

Water quality criteria associated with specific ambient water

uses when adopted as State water quality standards under section

303 become enforceable maximum acceptable levels of a pollutant

in ambient waters. The water quality criteria adopted in the

State water quality standards could have the same numerical

limits as the criteria developed under section 304. However, in

many situations States may want to adjust water quality criteria

developed under section 304 to reflect local environmental condi-

tions and human exposure patterns before incorporation into water

quality standards. It is not until their adoption as part of the

State water quality standards that the criteria become regulatory.

The bacteriological water quality criteria recommended in

this document are based on an estimate of bacterial indicator

counts and gastrointestinal illness rates that are currently

being accepted, albeit unknowingly in many instances, by the

States. Wherever bacteriological indicator counts can consistently

be calculated to give illness rates lower than the general

estimate,

or when the State desires a lower illness rate, indicator bacteria

levels comensurate with the lower rate should be maintained in

State

water quality standards.

Guidelines to assist the States in modification of criteria

presented in this document, in the development of water quality

standards, and in other water-related programs of this Agency,

have been developed by EPA.

artieLfri

/64(11*—

■

Director

Criteria and Standards

Division

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ACKNOWLEDGEMENTS

Alfred P. Dufour

(research-author)

Health

Effects Research

Laboratory

Cincinnati, OH

Theadore H. Ericksen

(review)

HERL'

Cincinnati, OH

Richard K. Ballantine

(author)

OWRS - Washington, D.C.

Victor

J.

Cabelli

(research)

Health Effects Research

Laboratory

West Kingston, RI

Miriam Goldberg

(statistical

assistance)

OWRS

Washington,

D.C.

William E. Fox

(coordinator)

OWRS - Washington, D.C.

iv

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BACTERIOLOGICAL AMBIENT WATER QUALITY CRIT-ERZA

FOR

MARINE AND FRESH RECREATIONAL WATERS

Introduction

Federal water quality criteria recanmendations were first proposed

in 1968 by the National Technical Advisory Committee (NTAC) of the

Department of the Interior (1). Tne microbiological criterion suggested

by the NTAC for bathing waters was based on a series of studies conducted

during the late 1940's and early 1950's, by the United States Public

Health Service, the results of which were 'summarized by Stevenson in 1353

(2). I've studies were conducted at bathing beaches located on Lake Michi-

gan at Chicago, Illinois; on the Ohio River at Dayton, Kentucky;

and on

Long Island Sound at Mamaroneck and

New

Rochelle, New York. All of the

studies followed a similar design. No beaches

with

different water

quality were selected at each location except at the Clayton location

where a beach with high quality water could not be found. A large public

swimming pool was used as a substitute. Each location was chosen because,

in addition to beaches having suitable water quality, there was a large

residential population 'nearby that used the

beaches.

Cooperating families

used a calendar system which allowed than to record their swimming activity

and illnesses on a daily basis for the entire summer. Gastrointestinal,

respiratory, and other symptoms such as skin irritations. were recorded.

The water quality was measured on a routine basis

using total

conform

bacteria as the indicator organise.

The results of the Lake Michigan beach study indicated that there

was no excess illnesses of any type in swimmers at beaches that had

median coliform densities of 91 and 180 per

100 ml over a swimming season

when compared to the number of illnesses in the total study population..

The water quality similarity at the two Chicago beaches

was unexpected

since previous experience had indicated that there was a difference in

water quality at the beaches. A second method of analysis compared the

illness observed in the week following three days of high

coliform

density

with that observed following swimming on three days of low coliform

density. The analyses showed that there was a significantly greater

illness rate in individuals who swan on the three days when the geometric

mean coliform density was 2300/100

ml

when compered

to the illness in

swimmers who swam on the three days.

hen the geometric

mean coliform

density was 43 per 100 ml.

A difference

was not

observed when the

geo-

metric mean coliform density per 100 ml on high

and

low

days

was

732 and

32 respectively. Data

from

the

Chio

River study indicated that swimmers

who swan in

water

with a median coliform density of 2300 conforms per

100

ml had

an excess

of gastrointestinal illness when compared to an

expected rate calculated from the

total study population. No

other

associations between swimming and

illness

were observed.

The results of

two marine bathing beach

studies showed no

association

between illness

and swimming in

water

containing 398 and 815

conforms

per

100

ml.

The coliform

water quality index used during the USPHS

epidemiologi-

cal studies was translated into

a

fecal

conform

index

in the mid-'60s

by

using the ratio of fecal coliforms

to

coliforms at

the

location on the

Chio River where

the

original study had been conducted

in

1949. The

NTAC

canmittee suggested that the change was necessary because fecal coliforms

---

were more fecal specific and less subject to variation than total

coli-

forms which were

greatly influenced by storm water runoff. About 18% of

the coliforms

were

found to be

fecal coliforms and

this proportion was

used to

determine that the equivalent of

2300 coliforms

per 100 ml, the

density at which a statistically significant swimming-associated gastro-

intestinal illness was observed, was about 400 fecal conforms per 100

ml. The

grAC

suggested that a detectable risk was undesirable and,

therefore, one-half of the density at which a health risk occurred, 200

fecal conforms per 100 ml, was proposed. The NTAC also suggested that

the use of the water should not cause a detectable health effect more

than 10% of the

time. Thus, the recommended criterion for recreational

waters

was as follows:

"Fecal conforms should be used

as

the indicator organism.

for evaluating

the microbiological

suitability of recreation

waters. As determined by multiple-tube fermentation or mem-

brane filter procedures and based on a minimum of not less than

five samples taken over not more than a 30-day period, the •

fecal

coliform content of primary contact recreation waters

shall not

exceed a

log mean of 200/100

ml,

nor shall more than

10 percent of total

samples

during any 30-day period exceed

400/100 ml."

This criterion was recommended

again in

1976 by the

USEPA (3), even

though it

had been

criticized on a number of issues. Henderson (4)

published one of the earliest critiques of the reammended criterion. He

noted the paucity of epidemiological data

in support of any numerical

ceilings based on fecal

indicators and criticized the one proposed

as to

the poor quality of the data base, the derivation of the specific limits

and the indicator system used.

Moore (5) objected to the selection of only part of the data from

the Lake Michigan study to develop the 200 fecal conforms

per

100 ml

recreational water criterion. He

observed

that opposite findings in the

Lake Michigan studies

were ignored. He

pointed out that the inclusion of

all illnesses reported during the week after a

bathing

episode

made the

association of these

ailments with

the bathing episode tenuous, and that

there was no way of

knowing whether

the incidence of skin irritations in

bathers who swan on

clean days

was compared to the frequency of diarrhea

in those who swam

on other

days, because all the illnesses reported were

lumped

together.

Cabelli et al. (6) suggested other weaknesses in the USPES study

design which

TigErhave

precluded the identification of swimming-associ-

ated, pollution-related

illnesses

if, in

fact, they occurred. They

pointed out that

"swimming" was poorly

defined and that it was unknown

whether or not study

participants who said

they had been swimming actually

immersed their bodies, much less their heads, in the water. This short-

caming and the use of the calendar method for recording "swimming" epi-

sodes and illnesses also was criticized as precluding the inclusion of

beachgoing but

nonswiming

control groups in

the

studies.

Moreover,

the

use of the

calendar

approach with

nearby residents and the day-to-day

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- 3 -

variability in the pollution levels at the beaches increases the probabi-

lity of a given individual's exposure to different levels of pollution

during the incubation period of the illness.

The deficiencies in the study design and

in the

data used to

establish the 200 fecal coliforms per 100 ml criterion were noted by

the National Academy

of Science - National Academy of Engineers Cannittee

in their 1972 report which stated that they could not recommend a

recreational water quality criterion because of the paucity of epidemi-

logical inforrnation available (7).

The fecal col iform indicator used to measure water quality under the

current system has also been faulted because of the non-fecal sources of.

at least one member of the fecal col ifonn group. For example, thenno-

tolerant

Klebsiella

species have many sources. They have been Observed

in pulp and paper mill effluents (8,9), textile processing plant effluents

(10), cotton mill wastewaters (11), and sugar beet wastes (12), in the

absence of fecal contamination.

The Environmental Protection Agency, in 1972, initiated a series of

studies at marine and fresh water bathing beaches which were designed to

correct the perceived deficiencies of the Public Health

Service

studies.

One goal of the EPA studies was to determine if swimming in

sewage-

contaminated water carries a health risk for bathers; and, if so, to what

type of illness. If a quantitative relationship between water quality

and health risk was obtained, two additional goals were to determine

which bacterial indicator is best correlated to swirmning-associated

health effects and if the relationship is strong enough

to provide a

criterion.

Study Design

The marine studies were conducted at bathing beaches in

New York

City, New

York, Boston, Massachusetts,

and at Lake Pontchartrain, near

New Orleans, Louisiana.

TWo

beaches were selected at each site, one that

received very little or no contamination and the other

whose water quali-

ty was barely acceptable with respect

tr,

local recreational water quality

standards. In the

New York

City and Boston Harbor studies, the "barely

acceptable"

beaches

were ccntmminated

with pollution from multiple point-

sources, usually treated effluents that had been disinfected.

The freshwater studies were conducted on Lake Erie at Erie,

Pennsylvania and on Keystone Lake outside

of Itilsa, Oklahoma. The "barely

acceptable"

beaches

at both sites were contaminated by effluents dis-

charged from single point-souroes.

The epidemiological surveys were carried

out on weekend days and

individuals who swan in the midweeks before

and after a survey were

eliminated from the study. This maximized the study populations; allowed

the

water quality measurements for a

single day to

be specifically as-

sociated with the corresponding illness rates, and permitted the grouping

of days with similar water quality levels and their corresponding study

populations. The design of the epidemiological survey portion of the

---

study has been described elsewhere (13,14).

Specific

steps taken to

correct the deficiencies of earlier studies were noted earlier.

In the initial phases of the overall study, multiple indicators of

water quality were used to monitor the water. This was done because it

was not known which indicator of water quality might show a quantitative

relationshi

p

with swimming-associated health effects. This unique ap-

proach resulted in the selection of the best indicator based on the

strength of the statistical relationship

between the water quality indica-

tor

and a swiming-associated health effect.

Each participant was querried at length about any illness symptoms,

their date of onset and the duration of the symptams. The symptoms were

grouped into four general categories, gastrointestinal, respiratory, eye,

ear and nose, and "other". Gastrointestinal symptoms included vomiting,

diarrhea, stomachache and nausea. Sore throat, bad cough and chest colds

comprised the respiratory symptoms, and runny or stuffy nose, earache or

runny ears and red,

itchy or watery eyes were considered symptomatic of

eye, ear or nose problems. Other symptoms included fever greater than

1000

F,

headache for more than a few hours or backache.

All of the symptoms were self-diagnosed and therefore subject to

variable

interpretation. The

potential for misinterpretation was mini-

mized by creating a new symptan category called highly credible gastro-

intestinal symptoms. This symptom category was defined as including any

one of the following unmistakable or combinations of symptans: (1)

vomiting, (2) diarrhea with fever or a disabling

condition (remained

ham, remained in bed or

sought medical advice because of the symptoms)

and (3) stomachache or nausea accampanied by a fever.

Individuals in

this symptom category were considered to have acute gastroenteritis.

Data Base for Marine and Fresh Water Criteria

The results of the marine Bathing Beach Studies have been reported by

Cabelli (15) and those of the freshwater studies have been described by

Dufour (16). In general, those symptom categories unrelated to gastro-

enteritis usually

did

rot show a significant excess of illnesses at

either of the paired beaches at each study location. Moreover, the

significant swimming-associated rates for gastroenteritis were always

observed at the more polluted of the paired beaches at each study loca-

tion.

Table 1 shows the number of occasions when significant winning-

associated gastroenteritis was observed at barely acceptable and rela-

tively unpolluted marine and fresh water

beaches. Statistically signifi-

cant

swimming-associated

gastroenteritis rates

were rot observed at any

of the

relatively

unpolluted beaches. The occurrence of a statistically

significant excess of swimming-associated

gastroenteritis in

swimmers who

bathed at beaches that

were,

by selection, more polluted is indicative

that there is an increased risk

of illness

fran swimming

in

water oontami-

nated with treated sewage, i.e., both swimming-associated and pollution-

related. This finding, which was observed at both marine and fresh water

locations was important because it placed in proper perspective the

relationship between water contaminated with treated sewage and health

risks for swinners. This association was not very well defined

in

the

---

5

earlier USPHS studies. The only evidence that sewage-contaminated water

carried a risk for gastroenteritis in those studies was observed at the

Ohio River beach where swimmers had an excess of gastrointestinal illness

when the

median coliform density in the water was 2300 per

100

ml. This

was counter to the results found at freshwater beaches in Chicago and at

marine beaches on Long Island Sound where swirrers had no more gastro-

intestinal illness than nonswimmers even when days of "high" and "low"

coliform densities were selected. Therefore, other than the occasional

association of an outbreak of disease with swimming (17), the data from

7.abetli (15) and

Dafour (16) are the only available

evidence

linking

sewage contaminated water with a health risk for bathers.

Although the association of

illness in swiniers using bathing water

contaminated by treated sewage

is

an important aspect of the process for

developing recreational water quality criteria, it is the establishment

of a quantitative relationship between the two variables that provides a

useful relationship for regulating water quality. A part of this process

is the development of suitable methods for measuring the quality of the

water.

A comprehensive discussion of microbial water quality indicators is

beyond the scope of this document, even as the basis for the selection of

those examined in the epidemiological studies. The reader is referred

for this to

the reports of the studies (15,16)

and

to reviews on the

subject (18,19). The examination of a number of potential indicators,

including the ones most commonly used in the United States (total conforms

and fecal coliforms), was included in the studies. Furthermore, the

selection of the best indicator was based on the strength of the relation-

ship between the rate of gastroenteritis and the indicator density, as

measured with the Pearson Correlation Coefficient. This coefficient

varies between minus one and plus one.

A

value

of one indicates a

perfect relationship, that

is,

all of the paired points lie directly on

the line which defines the relationship.

A

value of zero means that

there

is

no linear relationship. A positive value indicates that the

relationship is direct, one variable increases as the other increases.

A negative value indicates the relationship

is inverse,

one variable

decreases as the other

increases.

The correlation coefficients for

gastroenteritis rates as related to the various indicators of water

quality from both

marine and

fresh bathing water are shown in Table 2.

The

data

free the three years

of the

New York

City study were ana-

lyzed in two ways. The first was by grouping trial days with similar

indicator densities from

a given swimming season

and the second was by

looking at

each entire summer.

The results from both analyses are shown

in Table 2.

Per either

type of analysis, enterocccci showed the strong-

est relationship to gastroenteritis. E.

coli was a very poor

second and

all of the other

indicators, including total ccliforms and fecal

ccai-

forms,

showed very

weak correlations

to

gastroenteritis. Enterccocci and

E. coli were used in subsequent studies including the freshwater

trials.

Fecir

-

COlifonts also

were included in subsequent

studies

because of their

status as an accepted basis for a criterion.

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-6 -

The freshwater studies were analyzed only by sinner. The oorrela

tion coefficient for E. coli was slightly greater than

that

for entero-

cocci,

however, statistical

-analysis

indicated that the two values were

not significantly different. Fecal conforms, on the other hand, had a

correlation coefficient that was very similar to that Observed for fecal

coliforms from the marine data analyzed by summer. The freshwater stu-

dies confided the findings of the marine studies with respect to entero-

cccci and fecal coliforms in that the densities of the former in bathing

water showed strong correlation with swimming-associated gastroenteritis

rates and densities of the latter showed no correlation at all. The

similarities in the relationships of E. coli and enterococci to swimming-

associated gastroenteritis in freshwater indicate that these two indica-

tors are equally efficient for monitoring water quality in freshwater,

whereas in marine water environments only enterococci provided a good

correlation. The etiological agent for the

acute

gastroenteritis is

probably viral (20). The ultimate source of the agent is human fecal

wastes. E. coli is the most fecal specific of the coliform indicators

(21); and enterococci, another fecal indicator, better emulates the virus

than do the conforms with respect

to

survival in marine waters (22).

Basis of Criteria for Marine and Fresh Recreational Waters

Cabelli

(15) defined

a recreational water quality criterion as

a

"quantifiable relationship between the density of an indicator in the

water and the potential human health

risks involved

in the water's recre-

ational use."

Fran

such a definition, a criterion now can be

adopted

by

a regulatory agency, which establishes upper limits for densities of

indicator bacteria in

waters

that are associated with acceptable health

risks for

swimmers.

The quantitative relationships

between the rates of swimming-associ-

ated health effects and bacterial indicator

densities

were determined

using regression analysis. Linear relationships

were

estimated from data

grouped on the

basis

of summers or trials with similar indicator densi-

ties. The data for each summer were

analyzed by

pairing the geometric

mean indicator density for a summer bathing season at each beach with the

corresponding swimming-associated gastrointestinal illness rate for the

same

summer.

The swimming-associated illness

rate was determined by

subtracting the gastrointestinal illness rate in nonswimmers fran that

for swimmers.

These two variables

from multiple beach sites were used to

calculate

a regression

coefficient, y-intercept and 95% confidence inter-

vals for the

paired

data. In

the marine

studies the

total number of

points for use

in regression analysis

was

increased

by collecting trial

days with similar indicator densities fran each study location and placing

them into groups. The swimming-associated

illness rate

was determined as

before, by subtracting the nonswimmer illness rate of all the individuals

included in the grouped

trial

days from the swimmer illness rate during

these same grouped trial days. The grouping by trial days with similar

indicator densities approach was not possible with the

freshwater

data

because the variation

of

bacterial indicator densities in freshwater

samples was not large enough to allow such an adjustment to be made.

---

For the saltwater studies the results of the regression analyses of

illness rates against indicator density data was very similar using the

"by summer" or "by grouped trial days" approaches. The data grouped by

trial days will be used here because of the broader range of indicator

densities available for analysis. Table 3 shows the results of the

marine and fresh water bathing beach studies conducted from 1973 through

1982. These data were used to define the relationships between swimming-

associated gastroenteritis and bacterial indicator densities presented

below.

The methods used to enumerate the bacterial indicator densities

which showed the best relationship to swimming-associated gastroenteritis

.rates were specifically developed for the recreational water quality

studies. The membrane filter procedure for enumerating enterccocci was

developed by Levin et al. (23). Evaluation of the method using fresh and

marine water samples indicated that it detects mainly Streptococcus

faecalis and Streptococcus faecium. Although these two species were

thought to be more human spi7M7than other Streptococci, they have been

found in the intestinal tract of other warm-blooded animals such as cats,

dogs, cows, horses and sheep.

E. coli were enumerated usingthe membrane filter procedure developed'

by CuTiOur et al. (24). Evaluation of this method with marine and fresh

water samples has shown that 92 to 95% of the colonies isolated were

confirmed as E. coli.

•

These membrane filter methods have successfully undergone precision

and bias testing by the EPA Environmental Monitoring and

Support Laboratory.

The test methods are available in the

-

EPA Research and

revelopment report,

EPA-600/4-85/076 Test Methods for Escherichia

cola

and Enterococci in

Water

by

the Membrane F ter

Recommendations on Bacterial Criteria Monitoring

Several monitoring situations to assess bacterial

4uality

are encountered

by regulatory agencies. The situation needing the most rigorous monitoring

is

the designated

swimming

beach. Such areas are frequently lifeguard

protected, provide parking

and

other public access and are heavily used by

the public. Public beaches of this type were used by EPA in developing the

relationship described in this document.

Other

recreational

activities may involve bodies

of water which are

regulated

by individual

State water quality standards. These recreational

resources may be natural wading ponds used by children or waters where

incidental full body

,

contact occurs because of water skiing or other

similar activities.

It is EPA's judgement that the monitoring

req

uirements

for these

various recreational activities

are

different.

For

the public beaches,

more frequent sampling is

required

to

verify the

continued

safety of the

waters for swimming, and to identify

water quality

changes

which might

impair

the health

of

the public. Increasing

the

number of

samples

im-

proves the accuracy of bacterial water quality

estimates,

and also

---

improves the likelihood of correct decisions on whether to close

or leave open a beach.

waters with more casual and intermittent

swirmning use

need fewer

samples because of the reduced population at risk. Such sampling may

also be used in establishing trends in the bacterial water quality so

that the necessary improvements in the sanitary quality can be identified

before disease risks became acute.

The following compliarce protocol is one recamended by EPA for

monitoring recreational bathing waters. it is based on the assumption

that the currently accepted risk level based on the CO4 reccmmendation

has been determined

to be appropriate and that the monitoring methods,

i.e., bacterial enumeration techniques are imprecise, and envircxmlental

conditions,

such as rainfall, wind and temperature

will

vary temporally

and spatially. The variable nature of the environment, which affects

the die-off and transport of bacterial indicators, and the inherent

imprecision of bacterial enumeration methods, suggests an approach that

takes these elements into account. Noncompliance with the criterion

is signaled when the maximum

acceptable

geometric mean is exceeded or

when

any individual sample exceeds

a confidence limit, chosen accordingly

or to a level of swimming use. The mean log standard

deviation

for E.

coli densities at the nine freshwater beach sites that were studied was

about 0.4. The mean log standard deviation

for

enterococci

in freshwater

samples was also

about 0.4

and in seawater samples it was about 0.7.

These too values, 0.4 anal

0.7 will be used in calculations associated

with the proposed monitoring protocol and upper percentile values.

It

is recommended that sampling frequency be related to the intensity

of use of the water body. In areas where weekend use is substantial, -

weekly samples collected during the peak use periods are reasonable. In

less heavily used areas perhaps bi-weekly

or

monthly samples may be

adequate to decide bacterial water quality. .In general, samples should

be collected during dry weather periods to establish so-called "steady

state" conditions. Special studies may be necessary to evaluate the

effects of wet weather conditions on waters of interest especially if

sanitary surveys indicate

the area may

be subject to storm water effects.

The water samples are collected

in

sterile sampling containers

as

described in Standard Methods

for the Examination

of Water and

Wastewater

(25).

Development of Recommended Criteria

Based on

E.

coli/Enterococci

Currently EPA

is not recommending

a

change

in the stringency of its

bacterial criteria

for

recreational waters. Such

a

change does not

appear warranted until more information based on greater

experience

with

the

new

indicators can

be

accrued.

EPA and the State Agencies can then

evaluate

the impacts of

change in

terms of beach closures and other

restricted

uses. EPA recognizes that

it will take a period of at least

one triennial

review and revision

period

for States

to incorporate the

new

indicators into State Water

Quality

Standards

and

start

to accrue

experience with the new

indicators at

individual water use areas.

---

EPA's evaluation of the bacteriological data indicated that using

the

fecal ccliform indicator

group at the maximum geometric mean of 200 per

100 ml, recommended in

Quality Criteria

for Water would cause an estimated

8 illness per 1,000

swimmers

at fresh water beaches and 19 illness per

1,000 swimmers at marine beaches. These relationships are only approximate

and are based on applying ratios of the geometric means of the various

indicators from the EPA studies to the 200 per 100 ml fecal coliform

criterion. However, these are CPA's best estimates of the accepted

illness rates for areas which

apply the EPA fecal coliform criterion.

The E. coli and

enterococci

criteria presented in Table 4 were deve-

loped using these currently accepted illness rates. The eauations deve-

loped by Dufour(16) and

Cabelli(15)

were used to calculate the geometric

mean indicator densities corresponding to the accepted gastrointestinal

illness rates. These densiti.es are for steady state dry weather conditions.

The beach is in noncompliance with the criteria if the geometric mean

of

several bacterial

density samples exceeds the value listed in Table 4.

Noncompliance is also signalled by an unacceptably high value for

any single bacterial sample. The maximum acceptable bacterial density

for a single sample is set higher than that for the geometric mean, in

order to avoid unnecessary beach closings based on single samples. In

deciding whether a beach should be left open, it is the long term geometric

mean bacterial density that is of interest. Because of day-to-day fluctu-

ations around this mean, a decision based on a single sample

(or even

several samples) may be erroneous, i.e., the sample may

exceed

the recom-

mended mean criteria even though the long-term geometric mean is protective,

or may

fall below

the maximum even if this mean is in the

nonprotective

range.

To set the single sample maximum, it is necessary to specify the •

desired chance that the beach

will

be left open when the

protection is

adequate. This chance, or confidence level, was

based on Agency judgment.

For the simple decision rule considered here, a smaller confidence level

corresponds to a more stringent (i.e. lower) single sample maximum.

Conversely, a greater confidence level corresponds to less stringent

(i.e. higher) maximum values. This technique reduces the chances of

single samples inappropriately indicating violations of the recommended

criteria.

By using a control chart analogy (26) and the actual log standard

deviations fran the EPA studies, single sample maximum densities for

various confidence levels were calculated. EPA then assigned qualitative

use intensities to those confidence levels. A low confidence

level

(75%)

was assigned to

designated beach areas

because

a

high degree of caution

should be used to evaluate water quality for

heavily used areas. Lass

intensively used areas

would allow less

restrictive single sample limits.

Thus, 95% confidence might be appropriate for swimmable water in remote

areas. Table

4

summarizes the results of these. calculations. These

single sample maximum

levels should

be recalculated for

individual areas

if significant

differences

in log standard

deviations occur.

---

The levels displayed in Table 4 depend not only on the assumed

standard

deviation of log densities, but also on the chosen level of

acceptable risk. While this level was based on the historically accepted

risk, it is still arbitrary insofar as the historical risk was itself

arbitrary. A detailed protocol is available* which shows how to determine

the confidence level associated with any illness risk of interest, once a

maximum has been established for single samples.

The protocol also

indicates how the confidence level approach can be applied to multiple

sample geometric means. In Table

4, the limit for the

measured geometric

-lean is •etermined

directly from the

regression equation

relating

illnesses

to bacteriological density

, without

any "confidence level"

allowance for

random variations in the geometric mean of several

samples.

Limitations and Extrapolations of Criteria

The limitations of Water

Quality

Criteria based on swimming-associated

health effects and bacterial indicator densities have been addressed by

Cabelli(18). Briefly, the major limitations of the criteria are that the

observed relationship may not be valid if the size of the population

contributing the fecal wastes becomes too small or if epidemic conditions

are present in a community.

In

both cases the pathogen

to

indicator ratio,

which is approximately constant in a large population becomes unpredictable

and therefore, the criteria may not be reliable under these circumstances..

These two considerations point out the importance of sanitary surveys and

epidemiological surveillance as part of the monitoring

program.

The presence of these

indicators, in

rural

areas, shows

the presence

of warn blooded animal fecal pollution.

Therefore,

EPA remmmends the

application of these criteria unless sanitary and epidemiological studies

show the sources of the indicator bacteria to be non-human and that the

indicator densities are not indicative of

a

health risk to those swimming

in such

waters.

EPA is sponsoring research to study the health risk.of

nonpoint source pollution from rural areas on the safety of water for

swinzning. Definitive

evidence

from this study was not available at the

tine of preparation of this criterion, but will be incorporated into

subsequent revisions.

Relationship with the

Criterion

contained in

Quality

Criteria for Water

(QCW)

The 1976 QM

criterion

contained recommendations for both swimming

and

shellfish harvesting

waters. This criteria recommendation is intended

as

a

modification to the earlier criterion. Nothing in this criterion is

intended to

supersede

the

QCW

recommendations concerning the bacterial

quality of shellfish waters. EPA is currently co-sponsoring, with the

National Oceanic and Atmospheric

Administration,

research into the

* Procedures for Developing Com

pliance

Rules for Water Quality Protection

Criteria and Standards Divison

Office of Water Regulations and Standard

Environmental Protection Agency

401 M St., S.W.

Washington, EC

20640

---

-

application of the enterococci and E. coli indicators for assessing the

quality of shellfish harvesting waters. The rood and Drug Administration

is also reviewing the results of these studies. A change to the new

indicators may be forthcoming if the studies show a correlation between

gastrointestinal disease and the consumption of raw shellfish from waters

with defined densities of the new indicators. However, these studies

have not sufficiently progressed to justify any change at this time.

Thus, the recommendations in QCW for shellfish waters must remain unchanged.

The QCW recamendations for swthriing waters were based on Eecal

coliforms. Data submitted to EA during the public comment period snowed

that within some beaches, a correlation could be shown between E. coli

densities and fecal coliform densities. Such a site-specific correlation

is not surprising because E. coli is part of the fecal coliform group.

However, the EPA tests show that no general correlation exists across

different beaches. Therefore, EPA believes that the newly recommended

indicators are superior to

the fecal coliform group. Therefore, EPA

strongly recarmends that states begin the transition process

to

the new

indicators.

?

either E. coli or enterococci may be used for fresh

waters, only enterococci is recamtended for marine waters.

---

Table 1. Relationship Between Significant

Swinning-associated

Gastroenteritis and the

Degree

of Pollution at Marine

and Fresh Water Bathing Beaches

Beach Water Duality

Barely Acceptable

?

Relatively Unpolluted

No. Trials

?

17

?

8

`b. Trials

with

Excess Illness in

?

0

Swimmers1

% Trials with

Excess Swimmer

?

41?

0

Illness

1Difference

between swimmer and

nonswimmer illness rates during a

trial period statistically

significant

at p <0.05 level

---

IABLE 2. Correlation Coefficients for 941-ming-Associated

Gastroenteritis Rates Against Mean Indicator

Densities at Marine and Fresh Water Bathing Beaches

Type of

Water

Indicator

Correlation Coefficients

Data by?

Data by

Summers

?

Grouped Trials'

Marine2

enterococci

.75

.96

F: coli

.52

.56

Kleiiiig

lla

.32

.61

Fmterobacter/Citrobacter

.26

.64

Total Coliforms

.19

.65

C. perfrimens

.19

.01

E.

22E2gir2ZIS

.19

.59

FecAItalforms

-.01

.51

A. hydrophila

-.09

.60

V. parahemolyticus

-.20

.42

Staphylococci

-.23

.60

Fresh3

enterococci

.74

E. cols

.80

Fecal Conforms

-.08

'Groups of trials (days) with similar mean

indicator densities

during a given summer

2

Cata from trials conducted at

New

York City beaches 1973-1975

(Reference 18)

3

Data frcm Reference 19

---

TABLE

3.

Stimmary of

Mean

Indicator Density--Swiinming-Association Gastroenteritis

Rates Fran Tri(d!i ot All U.S. studies

Type of

Water

Location

Beachl Year

E. coli

Dengif

Enterococcus

Density

Number

Swimmers

Number

Illnesses

Nunber

Nonswimmers

Nnoilher

illnesses

Gastroenteritis

Rate tier 1000

Marine

N.Y.C.

RW

1973

21.8

484

30.4

197

15.2

15.2

CI

91.2

474

.46.4

167

18

28.4

1974

3.6

1391

7.6

711

4.2

3.4

7.0

951

10.5

1009

6.9

3.6

13.5

625

16.0

419

2.4

13.6

31.5

831

18.1

440

18.1*

1975

5.7

2232

8.8

935

19.3

-0.5

20.3

1896

14.8

678

7.4

7.4

154

579

34.5

191

-

34.5*

Lake

Pontchartrain

I.

1977

44

874

32

451

11.1

20.9*

224

720

31.9

456

8.8

23.1*

495

895

35.8

464

8.6

27.2*

L

1978

11.1

1230

36.6

415

14.5

22.1*

F

14.4

248

44.3

303

23.1

21.2

L

142

801

42.4

322

15.5

26.9*

Boston. Harbor

RE

1978

43

697

23

529

11

12

N

7.3

1130

33

1099

28

5

RE

12.0

222

41

376

13

28*

Fresh

Lake Erie

A

1979

23

5.2

3020

17.2

2349

14.9

2.3

B

47

13

2056

19.5

2349

14.9

4.6

Keystone Lake

E

138

38.8

3059

20.6

970

15.5

5.1

W

19

6.8

2440

20

970

15.5

0.5

Lake Erie

A

1980

137

25

2907

16.5

2944

11.7

4.8

B

236

71

2427

26.4

2944

11.7

14.7*

Keystone Lake

E

52

23

5121

13.5

1211

8.3

5.2

W

71

20

3562

11.2

1211

8.3

3.0

Lake Erie

B

1982

146

20

4374

24.9

1650

13.9

11.0*

1

4i = Rockaways, CI = Coney Island, L = Levee Beach, F =

Fbntainbleu

Beach, R

=

Revere

Beach,

N - Nahant

Beach,

A = Beach 7, B = Beach 11, E = Washington Irving Cove Beach, W = Salt Creek Cove--Keyst,)1,e Ramp luachus

*

Indicates swimmer-nonswinmer illness rate

difference significant at p = 0.05 level

---

TABLE 4

CRITERIA FOR INDICATOR FOR BACTERIOLOGICAL DENSITIES

Single Sample Maximum Allowable Density (4), (5)

Acceptable Swimming

Associated Gastro-

enteritis Rate per

1000 swimmers

Freshwater

Steady State

Geometric Mean

Indicator

Density

Designated?

Moderate Full

Beach Area?

Body. Contact

(upper 75% C.L.)

?

Recreation

(upper 82% C.L.)

Lightly used

Full Body

Contact

Recreation

(upper 90% C.L.)

Infrequently

U!;ett

Full Body

Contdct

Recreation

(upper 95% C.L.)

enter000cci

8

3

3(

1)

61

89

108

151

E. coli

8

126(2)

235

298

406

576

Marine Water

enter000cci

19

35(

3

)

104

158

276

500

Notes:

(1)

Calculated to

nearest whole number using equation:

(mean

enterococci

density) = antilogio

illness

rate/1000 people + 6.28

9.40

(2)

Calculated to nearest whole number using equation:

(mean E. ooli density) = antilogio

illness rate/1000 people + 11.74

9.40

(3)

Calculated to nearest whole number using equation:

(mean enter000cci density) = antiloglo

illness

rate/1000 people - 0.20

12.17

(4)

(log

i o

standard

deviation)

[

Single sample

limit

=

antiloglo

(loglo

indicator geometric + Factordetermined x

mean density/100 ml) from areas

under

the Normal prob-

ability curve tor

the assumed level

of probability

The appropriate

factors for the indicated one

sided

75% C.L. - .675

82% C.L. - .935

90% C.L. - 1.28

95% C.L. - 1.65

confidence

levels

are:

(5) Based on

the

observed log standard deviations during the

EPA

studies:

0.4

1.,1

freshwater

E. coli

=

fl

ei

n

7 few

remeinn wAI-Ar Oni

-

ArnMPer;?

PArh

iftri.4Aioti(In?

.111•1

1'•0-4hlitill–

it

q tirrt)

---

EPA Criteria for Bathing (F.111

Body Contact) Recreational Waters

Freshwater

Based on a statistically sufficient nunter of samples (generally not

less than 5 samples equally spaced over a 30-day period), the geometric

mean of the indicated bacterial

densities should not exceed one

or the

other of the following:(1)

E.

coli?126 per 100 ml; or

enterococci?

33 per 100 ml;

no safncle should exceed a one sided confidence Unit (C.L.) calculated

_sing the following as guidance:

designated bathing beach

?

75% C.L.

moderate use for bathing

?

82% C.L.

light use for bathing

?

90% C.L.

infrequent use for bathing

?

95% C.L.

based on a site-specific log standard deviation, or if site data are

insufficient to establish a log standard deviation, then using 0.4 as the

log standard deviation for both indicators.

Marine Water

Based on a statistically sufficient number of samples (generally not

less than 5 samples equally spaced over a 30-day period), the geometric

mean of the enterococci densities should not

exceed

35 per 100 ml;

no sample should exceed a one sided confidence limit using the following

as guidance:

designated bathing beach ?

75% C.L.

moderate use for bathing

?

82% C.L.

light use for bathing

?

90% C.L.

infrequent

use for bathing?

95% C.L.

based on a site-specific log standard deviation, or if site data are

insufficient to establish a log standard deviation, then using 0.7 as the

log standard deviation.

Note

(1) -

Only one indicator should be used. The Regulatory agency

should

select

the appropriate indicator for its conditions.

---

References

1.

\rational Technical Advisory Committee. 1968. Water Cuality Crite-

ria. Federal Water Poll. Control Adm., Deot. of the Interior,

Washing

ton, CC.

2.

Stevenson, A. H. 1953. studies of Bathing Water Quality and Health.

Am.

J.

Public Hlth. Assoc. 43:529.

3.

U.S. -Environmental Protection Agency. 1976. Cuality Criteria for

Water. U. S.

Environmental

Protection Agency, Washington,

DC.

Henderson,

I.

M. 1968. Enteric Disease Criteria for Recreaticnai

:esters.

J. San. Eng. Div.

94:1253.

5. Moore, B. 1975.

The Case Against Microbial Standards

for Bathing

Beaches.

In:

International Symposium on

Discharge of Sewage From

Sea Out falls. Ed. A. L. H. Gameson. Pergamcn Press, London. p. 103.

6.

Cabelli, V. J.,

M. A. Levin,

A. P. Dufour,

and

L.

J.

McCabe. 1975.

The Development of Criteria for Recreational Waters. In: Interna-

tional

Symposium

on Discharge of Sewage Fran Sea Cutfalls. Ed. A.

L. H. Gmneson. Pergamcn Press, London.

p.

63.

7.

Cannittee on Water Quality Criteria. 1972. National Academy of

Sciences-National Academy of Engineering. Water Quality Criteria.

U.S. Environmental Protection Agency, EPA-R3-73-033, Washington, DC.

8.

Huntley, B. E., A. C. Jones, and V.

J.

Cabelli. 1976. Klebsiella

Densities in Waters Receiving Wood Pulp Effluents. J. Water Poll.

Control

Fed. 48:1766.

9. Caplenas, N. R.,

M. S.

Kanarek,

and

A. P. Dufour. 1981. Source and

Extent of

Klebsiella ppeumoniae

in the

Paper Industry.

Appl. En-

virons Microbiol. 42:779.

10.

Dufour, A. P., and V. J. Cabelli. 1976. Characteristics of Kleb-

siella Fran Textile Finishing Plant Effluents.

J.

Water Poll.

Control Fed. 48:872.

11. Campbell, L.

M.,

G. Michaels, R. D. Klein, and I. L. Roth. 1976.

Isolation of

Klebsiella pneumoniae Fran

Lake Water. Can.

J.

Micro-

biol. 22:1762.

12. Nunez, W. J., and

A.

R. Colmer. 1968. Differentiation of

Aeratecter-

Klebeiella

Isolated from Sugar Cane. Appl. Micrcbiol. .16:875.

13.

Cabelli,?

A.

P. Dufour, M. A.

Levin,

L. J.

McCabe, and P. W.

Haberman. 1979. Relationship of Microbial Indicators to Health

Effects at Marine Bathing Beaches.

Am. J.

Public filth. 69:690.

14. Cabelli, V. J., A. P. Dufour.

L.

J.

McCabe, and M.

A.

Levin. 1982.

Swimming-Associated Gastroenteritis and Water

Quality. Am. J.

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J.

1983. Health Effects Criteria for Marine Recreation-

al

Waters. U.S. Environmental Protection Agency,

EPA-600/1-80-03l,

Cincinnati, OH.

-17-

---

16.

Dufour, A. P. 1984. Health Effects Criteria for Fresh Recreational

Waters. U.S. Environmental Protection Agency, Cincinnati, OH.

EPA 600/1-84-004

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Disinfection of Water and Wastewater. Eds. M. Butler, A. R.

Medlen, and R. Morris. University of Surrey, Surrey, England.

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Cabelli, V.

J. 1976. Indicators of Recreational Water Quality.

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Water.

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W.

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14. Cabelli, V. J. 1982. Microbial Indicator Systems for Assessing

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J. 1981. Epidemiology of Enteric Viral Infections.

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Vasl,

E.

Katzenelson,

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Survival of

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24.

Dufcur, A. P., E. R. Strickland, and V. J. Cabelli. 1981. Membrane

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---