U.S. Department of the Interior

U.S. Geological Survey

Concentrations of Escherichia coli in Streams

in the Ohio River Watershed in Indiana,

May–August 2000

By Cheryl A. Silcox, Bret A. Robinson, and Timothy C. Willoughby

Prepared in cooperation with the

Indiana Department of Environmental Management

Water-Resources Investigation Report 02-4064

Indianapolis, Indiana

2002
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

The use of trade, product, or firm names is for descriptive purposes only

and does not imply endorsement by the U.S. Government.

For additional information, write to:

District Chief

U.S. Geological Survey

5957 Lakeside Boulevard

Indianapolis, IN 46278-1996

Copies of this report can be purchased from:

U.S. Geological Survey

Branch of Information Services

Box 25286

Federal Center

Denver, CO 80225-0286
 Contents iii

Contents

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Description of the Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Study Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Selection of Sampling Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Field Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Collection of Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Processing of Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Geometric Mean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Statistical Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Quality-Assurance Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Concentrations of Escherichia coli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Relation between Concentrations of Escherichia coli and Streamflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Relation between Concentrations of Escherichia coli and Turbidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Quality-Assurance Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Filter Blanks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Process Blanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Field Blanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Duplicate Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Supplemental Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figures

1–4. Maps showing:

1. Location and principal streams of the Ohio River Watershed in Indiana . . . . . . . . . . . . . . . . . . . . . . 3

2. Location of sampling sites in the Ohio River Watershed in Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3. Ranges in concentrations of Escherichia coli for sampling sites in the Ohio River Watershed in

Indiana, May–August 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4. Five-sample geometric mean Escherichia coli concentration determined for sampling sites in

the Ohio River Watershed in Indiana, May–August 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5–7. Graphs showing:

5. Concentrations of Escherichia coli and five-sample geometric means for selected sites in the

Ohio River Watershed in Indiana, May–June 2000. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

6. Concentrations of Escherichia coli and five-sample geometric means for selected sites in the

Ohio River Watershed in Indiana, July–August 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

7. Stream discharge and concentrations of Escherichia coli for selected sites in the Ohio River

Watershed in Indiana, May–August 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
iv Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000

Contents—Continued

Figures—Continued

8–9. Graphs showing:

8. Turbidity and concentrations of Escherichia coli measured in samples collected at sites in the

Upper and Lower Wabash, Kankakee, and Ohio River Watersheds in Indiana, June–September

1998 and 1999 and May–August 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

9. Difference between concentrations of Escherichia coli in environmental and duplicate samples

and their natural log-percent differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Tables

1. Group 1 sites in the Ohio River Watershed in Indiana at which water samples were collected during

May and June 2000 for analysis of Escherichia coli. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2. Group 2 sites in the Ohio River Watershed in Indiana at which water samples were collected during

July and August 2000 for analysis of Escherichia coli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000 . . . . . 28

 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River

Watershed in Indiana, May–August 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Conversion Factors, Abbreviations, and Definitions

Contents v

Multiply By To obtain

foot (ft) 0.3048 meter

mile (mi) 1.609 kilometer

square mile (mi2) 2.590 square kilometer

cubic foot per second (ft3/s) 0.02832 cubic meter per second

pound per square inch (lb/in2

) 70.307 gram per square centimeter

Temperature is given in degrees Celsius (°C), which can be converted to degrees Fahrenheit (°F) by use of the following equation:

°F = 1.8(°C) + 32

Abbreviated water-quality units used in this report: Chemical concentrations and water temperature are given in metric

units. Chemical concentration is given in milligrams per liter (mg/L) or micrograms per liter (μg/L). Milligrams per liter is a

unit expressing the concentration of chemical constituents in solution as weight (milligrams) of solute per unit volume (liter)

of water. One thousand micrograms per liter is equivalent to one milligram per liter. For concentrations less than 7,000 mg/L,

the numerical value is the same as for concentrations in parts per million. Concentrations of bacteria are given in colonies per

100 milliliters (col/100 mL).

Bacteria are microscopic unicellular organisms, typically spherical, rodlike, or spiral and threadlike in shape, often clumped

into colonies.

Escherichia coli (E. coli) bacteria are present in the intestine and feces of warm-blooded animals. E. coli are a member species

of the fecal coliform group of indicator bacteria. Indicator bacteria for presumptive identification and enumeration are cultured

on selective media after filtration of several different sample volumes onto gridded membrane filters. In the laboratory, they

are defined as those bacteria that produce yellow or yellow-brown colonies that remain so when placed on a filter pad saturated

with urea substrate broth for 15 minutes after resuscitation at 35.0 ± 0.5°C for 2 hours and primary culturing for 22 to 24 hours at

44.5 ± 0.2°C on mTEC medium. Concentrations of bacteria are given in colonies per 100 milliliters (col/100 mL).

Dissolved oxygen (DO) content of water in equilibrium with air is a function of atmospheric pressure, temperature, and dissolvedsolids concentration of the water. The ability of water to retain oxygen decreases with increasing temperature or dissolved solids,

with small temperature changes having the more significant offset. Photosynthesis and respiration may cause diurnal variations

in dissolved-oxygen concentration in water from some streams.

Membrane filter (MF) is a thin microporous material of specific pore size used to filter bacteria, algae, and other very small

particles from water.

Membrane-filter Thermotolerant E. coli (mTEC) is a bacteria medium designed to encourage the growth of certain

indicator bacteria while restricting the growth of nontarget bacteria. Used for analysis of Escherichia coli, mTEC is a type of

membrane-filter media.

Nephelometric turbidity unit (NTU) is the unit of measurement for reporting turbidity that is based on use of a standard

suspension of Formazin. Turbidity measured in NTU uses nephelometric methods that depend on passing specific light of a

specific wavelength through the sample.
Conversion Factors, Abbreviations, and Definitions—Continued

vi Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000

pH of water is the negative logarithm of the hydrogen-ion activity. Solutions with pH less than 7 are termed “acidic,” and solutions

with a pH of greater than 7 are termed “basic.” Solutions with a pH of 7 are neutral. The presence and concentration of many

dissolved chemical constituents found in water are, in part, influenced by the hydrogen-ion activity of water. Biological processes

including growth, distribution of organisms, and toxicity of the water to organisms are also influenced, in part, by the hydrogenion activity of water.

River mile is the distance of a point on a river measured in miles from the river’s mouth along the low-water channel.

Specific conductance of water is expressed in microsiemens per centimeter at 25 degrees Celsius (μS/cm). This unit is equivalent

to micromhos per centimeter at 25 degrees Celsius (μmho/cm), formerly used by the U.S. Geological Survey.

Streamflow-gaging station is a site on a stream or canal where systematic observations of stage, discharge, or other hydrologic

data are obtained. When used in connection with a discharge record, the term is applied only to those streamflow-gaging stations

where a continuous record of discharge is computed.

Turbidity is a measurement of the collective optical properties of a water sample that cause light to be scattered and absorbed rather

than transmitted in straight lines; the higher the intensity of scattered light, the higher the turbidity. Turbidity is expressed in

nephelometric units (NTU) or Formazin turbidity units (FTU), depending on the method and equipment used.

Volumes of water-quality samples are given in liters (L) and milliliters (mL).
Abstract 1

Concentrations of Escherichia coli in Streams in the

Ohio River Watershed in Indiana, May–August 2000

By Cheryl A. Silcox, Bret A. Robinson, and Timothy C. Willoughby

Abstract

Water samples collected from 40 stream

sites in the Ohio River Watershed in Indiana

from May through August 2000 were analyzed

for concentrations of Escherichia coli (E. coli)

bacteria. Each site was sampled five times in a

30-day period. Concentrations of E. coli in 72

of the 200 samples exceeded the State of Indiana single-sample standard of 235 colonies per

100 milliliters for waters used for recreation.

A five-sample geometric mean of concentrations was computed for each site.

Concentrations in samples from 24 of the

40 sites exceeded the State of Indiana standard

for a five-sample geometric mean of 125 colonies per 100 milliliters for waters used for

recreation. Samples collected from 34 sites had

E. coli concentrations that exceeded either or

both the single-sample standard and the fivesample geometric mean standard.

Five of the 40 sampling sites were at

or near U.S. Geological Survey streamflowgaging stations. On the basis of records from

these stations, 16 percent of the samples

from these sites were collected at streamflows

above the median daily mean discharge for

each station.

E. coli concentrations and turbidity measurements collected during 2000 were analyzed

in concert with E. coli concentration and turbidity data collected in 1999 at streams within

the Kankakee and Lower Wabash River Watersheds in Indiana and in 1998 at streams within

the Upper Wabash River Watershed in Indiana.

These data were grouped together to investigate

the relation between concentrations of bacteria

and turbidity. The resulting analysis indicated

a statistically significant correlation between

concentrations of E. coli and turbidity.

Introduction

The presence of E. coli in water is direct

evidence of the presence of fecal contamination

from human or other warm-blooded animals and

indicates the possible presence of pathogens

(Myers and Sylvester, 1997; Francy and others,

2000). E. coli is one of the two preferred indicator

bacteria used by the U.S. Environmental Protection

Agency (USEPA) to determine the suitability of

surface waters for recreational use. Contact with

fecal-contaminated water puts swimmers at risk

of contracting gastrointestinal illness, skin rashes,

and ear and eye infections (Francy and others,

2000). The water-quality standards for E. coli in

recreational waters in Indiana require the concentration of E. coli to be less than the single-sample

standard of 235 colonies per 100 mL (milliliters)

and less than the geometric mean of 125 colonies

per 100 mL computed from five samples collected

within a 30-day period (Oddi, 1995).

The Indiana Department of Environmental

Management (IDEM) is responsible for monitoring

watersheds in Indiana and reporting the quality

of the State’s waters to Congress. IDEM has published those data for the year 2000 through the

State’s Report to Congress on Water Quality, 305B
2 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000

Report (Indiana Department of Environmental

Management, 2000). As part of this statewide

watershed-assessment program, IDEM entered

into a cooperative agreement with the U.S. Geological Survey (USGS) to determine concentrations

of E. coli at 40 stream sites in the Ohio River

Watershed from May through August. Previous

cooperative studies with IDEM determined E. coli

concentrations at 46 sites in the Upper Wabash

River Watershed in 1998 (Silcox and others, 2000)

and at 58 sites in the Kankakee and Lower Wabash

River Watersheds in 1999 (Silcox and others,

2001).

Purpose and Scope

This report documents the concentrations of

E. coli measured in samples from selected streams

in the Ohio River Watershed from May through

August 2000. The report also describes the relation

between concentrations of E. coli and streamflow

at sites where streamflow records were available

and examines the relation between concentrations

of E. coli and turbidity. Quality-assurance data for

the E. coli samples also are presented. Field measurements of water temperature, pH, dissolved

oxygen, specific conductance, and turbidity collected at the same time as the samples collected

for E. coli analysis also are presented in this report.

Description of the Study Area

Samples were collected in the Ohio River

Watershed in Indiana (fig. 1). This watershed,

which drains 4,224 mi2 in Indiana (Fenelon, Bobay,

and others, 1994, p. 177–181), includes all direct

tributaries to the Ohio River except the Wabash

River and Whitewater River Basins in Indiana.

The study area extended from near Aurora, Indiana

(Dearborn County), in the east to just west of

Evansville, Indiana (Vanderburgh County). Major

tributaries in the study area include Laughery Creek

(Ripley, Ohio, and Dearborn Counties), Indian

Creek1 (Switzerland County), Fourteenmile Creek

(Clark County), Indian Creek1 (Floyd and Harrison

Counties), Little Blue River (Crawford County),

Blue River (Washington and Crawford Counties),

Crooked Creek (Spencer County), Cypress Creek

(Warrick County), and Pigeon Creek (Vanderburgh

County).

The study area falls within seven physiographic units (Dearborn Upland, Muscatatuck

Regional Slope, Scottsburg Lowland, Norman

Upland, Mitchell Plain, Crawford Upland, and

Wabash Lowland) of southern Indiana (Schneider,

1966). In general, when compared to the glacially

derived topography of central and northern Indiana,

the Ohio River Watershed can be described as a

rugged area of relatively high topographic relief

with physical characteristics controlled by the

underlying bedrock.

Each physiographic unit within the Ohio River

Watershed, however, has its own distinct physical

characteristics distinguishing it from the other

units. The Dearborn Upland, Norman Upland, and

Crawford Upland physiographic units are underlain by relatively resistant rocks and show the

greatest relief where bedrock has been dissected

by streams. In places, the local relief in these three

physiographic units is as much as 450 ft (Schneider,

1966). In comparison, the Muscatatuck Regional

Slope, Scottsburg Lowland, and Wabash Lowland

exhibit less overall topographic relief.

Study Methods

Selection of sampling sites, methods used

to measure field parameters, and procedures

used to collect the samples to meet a 6-hour sampleholding time limit are described in the following

sections. Methods used to collect and process the

water samples for analysis of E. coli and the equation used to calculate the geometric mean are

discussed. Statistical methods used to evaluate

the relation between concentrations of E. coli and

turbidity also are described.

1There are two streams in the Ohio River Watershed

named Indian Creek. One is in Switzerland County and is just

west of the town of Vevay. The other Indian Creek drains

parts of Clark, Floyd, and Harrison Counties and is tributary

to the Ohio River southwest of Corydon, Ind.
SWITZERLAND

New Albany

Corydon

Madison

Vevay

Aurora

WASHINGTON

HARRISON

FLOYD

CLARK

SCOTT

JEFFERSON

RIPLEY

DECATUR

FRANKLIN

OHIO

DEARBORN

Laugh ery

C r.

N. Hog an Cr.

S. H ogan Cr.

Grant'sGoose 

Cr.

Cr

B

.

ryant Cr.

India n Cr.

Four et en Mile Cr.

Indian Cr. Indian Cr.

B uck Cr.

Blue River

Log Lick

Cr.

S i vl er Cr.

Ind i an -KentuckCr.

S. Fork 

Laughery Cr.

0 10 20 30 40 50

MILES

INDIANA

39 21'

85 37'50"

DEARBORN 

UPLAND

MUSCATATUCK

REGIONAL 

SLOPE

SCOTTSBURG

LOWLAND

NORMAN 

UPLAND 

CHELL

LAIN
4 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000

Selection of Sampling Sites

Sampling sites initially were selected by

IDEM personnel using responses from a 1987 poll

of local health officials, conservation officers, and

sheriff’s departments regarding known areas of

stream recreational uses. Additional sites then were

added to improve spatial coverage or to locate sites

at or near active USGS streamflow-gaging stations

where streamflow data was readily available. Site

locations were identified on topographic maps

and field verified for safety and accessibility by

USGS personnel prior to sample collection. Where

sampling conditions were unsafe or where site

characteristics interfered with the ability to collect

a sample, the sampling site was relocated as close

to the initial sampling site as possible. Changes to

sampling-site locations were agreed upon by USGS

and IDEM personnel.

The 40 selected sampling sites (fig. 2) were

divided into two groups so that all sites could be

sampled five times at equally spaced intervals

within a 30-day period. Table 1 lists the Group 1

sites (sites 1 through 12) sampled during May and

June 2000; table 2 lists the Group 2 sites (sites 13

through 40) sampled during July and August 2000.

Field Measurements

At each sampling site, a multi-parameter

water-quality probe was used to make field measurements of water temperature, dissolved oxygen,

pH, and specific conductance at several locations

across the width of the stream. The probes used

to measure dissolved oxygen, pH, and specific

conductance were calibrated daily. If parameters

measured in the field were not stable or if they

displayed unreasonable values, the meters were

recalibrated at the site and field parameters

were remeasured.

Field determinations of turbidity were made

by collecting samples of streamwater in polyethylene bottles and analyzing the samples with

a portable turbidimeter. The measuring range of

the turbidimeter was checked daily with reference

standards. Water temperature, dissolved-oxygen

concentration, pH, specific conductance, and turbidity were measured at the same locations in

the stream where the samples were collected for

analysis of E. coli.

Collection of Samples

Water samples were collected during Indiana’s recreational season, defined as April through

October. The samples were collected by two-person

field crews to expedite the sampling process and

to meet the mandated 6-hour sample-holding time

limit prior to processing the samples.

Activities at the sampling sites included

measuring and recording field parameters, measuring and recording water-surface-stage data, and

collecting the water samples for analysis of E. coli.

Water-surface stage was determined by using a

measuring tape lowered to the surface of the stream

from a reference mark on the bridge or documenting the stage levels of streams at sites where USGS

streamflow-gaging stations were present or nearby.

At the time of sampling, water-surface-stage elevation, water clarity, and weather conditions also were

noted on the field forms.

Water samples for E. coli determinations were

collected in 300 mL glass bottles with glass stoppers. Prior to use, the bottles were washed with

detergent, rinsed three times with tap water and

three times with deionized water, and then sterilized

by autoclaving. To ensure optimum growth conditions for E. coli, two solutions were added to each

sample bottle before the bottle was sterilized.

To counter the effects of residual chlorine or other

halogens used in water-disinfection processes,

0.3 mL of a 10-percent solution of sodium thiosulfate was added to the bottles. Residual chlorine

and other halogen compounds act as bacterialgrowth inhibitors; their effects need to be reduced

so that E. coli can fully recover on the growth

medium and produce accurate counts (Bordner and

Winter, 1978; American Public Health Association

and others, 1992).

In addition, 0.9 mL of a 15-percent solution of

ethylenediaminetetraacetic acid (EDTA) was added

to neutralize the effects of trace-element concentrations greater than 10 μg/L (micrograms per liter).
10

13

14

15 16

17

18

19 20

21

22

27

28

30

3

32

31 29

23

24

25

26

25

GROUP (1) ESCHERICHIA COLI SAMPLING SITES–

Sites sampled May and June 2000

GROUP (2) ESCHERICHIA COLI SAMPLING SITES–

Sites sampled July and August 2000

1

2

4 7

8 10 9

11

12

5

6

3

COUNTY BOUNDARY

WATERSHED BOUNDARY

EXPLANATION

39 21'

85 37'50"

0 10 20 30 40 50

MILES

ESCHERICHIA COLI SAMPLING SITES–

collected at or near U.S. Geological Survey active 

streamflow-gaging stations

*

*

*

*

*

*
6 Concentrations of Escherichia coli, Ohio River Wattershed, Indiana, May–August 2000

Table 1. Group 1 sites in the Ohio River Watershed in Indiana at which water samples were collected during May and

June 2000 for analysis of Escherichia coli

[USGS, U.S. Geological Survey; SR, State Road; *, denotes active USGS streamflow-gaging station]

Site

number Site location

USGS site

identification Latitude and longitude County

1 Laughery Creek at SR 350 near Osgood 390854085151301 39 ̊ 08 ́ 54 ̋ 85 ̊ 15 ́ 13 ̋ Ripley

2 Laughery Creek at SR 62 at Friendship 385821085091101 38 ̊ 58 ́ 21 ̋ 85 ̊ 09 ́ 11 ̋ Ripley

3 Laughery Creek at Cole Lane at Hartford 385941084572801 38 ̊ 59 ́ 41 ̋ 84 ̊ 57 ́ 28 ̋ Ohio

4 South Fork Laughery Creek at SR 262

at Milton

385812085003001 38 ̊ 58 ́ 12 ̋ 85 ̊ 00 ́ 30 ̋ Ohio

5 North Hogan Creek at North Hogan Road

near Wilmington

390444084574601 39 ̊ 04 ́ 44 ̋ 84 ̊ 57 ́ 46 ̋ Dearborn

6 South Hogan Creek near Dillsboro 03276700 39 ̊ 01 ́ 47 ̋ 85 ̊ 02 ́ 17 ̋ Dearborn

7 Grant’s Creek at Barkworks Road near

Quercus Grove

385306084541201 38 ̊ 53 ́ 06 ̋ 84 ̊ 54 ́ 12 ̋ Switzerland

8 Goose Creek at SR 156 at Patriot 385042084490701 38 ̊ 50 ́ 42 ̋ 84 ̊ 49 ́ 07 ̋ Switzerland

9 Bryant Creek at Private Drive, 1 river mile

upstream from SR 156

384835084520301 38 ̊ 48 ́ 35 ̋ 84 ̊ 52 ́ 03 ̋ Switzerland

10 Log Lick Creek at Bennett Road

near Markland

384713084583101 38 ̊ 47 ́ 13 ̋ 84 ̊ 58 ́ 31 ̋ Switzerland

11 Indian Creek at SR 129 near Vevay 384443085054101 38 ̊ 44 ́ 43 ̋ 85 ̊ 05 ́ 41 ̋ Switzerland

12* Indian-Kentuck Creek at SR 62 near

Canaan

03291780 38 ̊ 52 ́ 41 ̋ 85 ̊ 15 ́ 26 ̋ Jefferson

EDTA, a chelating agent, binds particularly with

copper and zinc, making the metals neutral so that

they do not adversely affect bacterial growth (Britton and Greeson, 1989, p. 5–6; Bordner and Winter,

1978; American Public Health Association and

others, 1992).

Samples were collected with a weighted handline sampler that was lowered beneath the surface

of the water. Grab samples were collected by immersing the bottles by hand when the stream was

not deep enough to use the hand-line sampler

(Myers and Slyvester, 1997). At each site, the

sample collected was a composite of water from

one to four well-mixed areas of flow, depending

on the width of the stream. The samples were kept

on ice until processed. Duplicate samples were

collected concurrently with the environmental

samples at selected sites.

Processing of Samples

Processing equipment included a multi-port

manifold filter stand, stainless-steel filter holders,

vacuum pumps, and glass graduated cylinders.

Equipment used to process the samples was washed

with detergent prior to field work, rinsed three

times with hot tap water and three times with deionized water, and then sterilized for a minimum

of 15 minutes with an 8-watt ultraviolet (UV) lamp

having a wavelength of 254 nanometers. Other

processing equipment used but not washed or

sterilized included vacuum pumps and sterile dis-
Study Methods 7

Table 2. Group 2 sites in the Ohio River Watershed in Indiana at which water samples were collected during July and

August 2000 for analysis of Escherichia coli

[USGS, U.S. Geological Survey; SR, State Road; CR, County Road; US, U.S.Highway; W, N, and S, denote the geographic directions of West,

North, and South; *, denotes active USGS streamflow-gaging station; ** , denotes site where streamflow data from nearby active USGS streamflow-gaging station was applied]

Site

number Site location

USGS site

identification Latitude and longitude County

13 Fourteenmile Creek at Zimmerman Road

at New Market

383156085370001 38 ̊ 31 ́ 56 ̋ 85 ̊ 37 ́ 00 ̋ Clark

14 Fourteenmile Creek at SR 62

near Charlestown

03292400 38 ̊ 27 ́ 57 ̋ 85 ̊ 37 ́ 05 ̋ Clark

15 Silver Creek at Blackiston Mill Road

near New Albany

0330000050 38 ̊ 20 ́ 03 ̋ 85 ̊ 47 ́ 41 ̋ Floyd

16 Indian Creek at Greenville Road

near Georgetown

381903086000701 38 ̊ 19 ́ 03 ̋ 86 ̊ 00 ́ 07 ̋ Floyd

17 Indian Creek at SR 335 near Corydon 03302500 38 ̊ 16 ́ 35 ̋ 86 ̊ 06 ́ 35 ̋ Harrison

18 Indian Creek downstream from

Little Indian Creek mouth at Corydon

381237086075801 38 ̊ 12 ́ 37 ̋ 86 ̊ 07 ́ 58 ̋ Harrison

19 Indian Creek at Lickford Bridge Road

near Central

380733086145101 38 ̊ 07 ́ 33 ̋ 86 ̊ 14 ́ 51 ̋ Harrison

20* Buck Creek at SR 337 near New Middletown 03302220 38 ̊ 07 ́ 13 ̋ 86 ̊ 05 ́ 17 ̋ Harrison

21 Little Blue River at SR 37 near Grantsburg 381709086290001 38 ̊ 17 ́ 09 ̋ 86 ̊ 29 ́ 00 ̋ Crawford

22 Little Blue River at CR 38 near Alton 380832086241001 38 ̊ 08 ́ 32 ̋ 86 ̊ 24 ́ 10 ̋ Crawford

23* Blue River at US 150 at Fredericksburg 03302800 38 ̊ 26 ́ 02 ̋ 86 ̊ 11 ́ 30 ̋ Washington

24 Blue River at Main Street at Milltown 382026086162501 38 ̊ 20 ́ 26 ̋ 86 ̊ 16 ́ 25 ̋ Crawford

25 Blue River at Rothrock Mill near Moberly 381628086163101 38 ̊ 16 ́ 28 ̋ 86 ̊ 16 ́ 31 ̋ Crawford

26** Blue River at SR 462 near White Cloud 381349086151301 38 ̊ 13 ́ 49 ̋ 86 ̊ 15 ́ 13 ̋ Crawford

27 Little Oil Creek at SR 66 near Dexter 380435086291701 38 ̊ 04 ́ 35 ̋ 86 ̊ 29 ́ 17 ̋ Perry

28 Poison Creek at CR 104 near Gerald 375903086334301 37 ̊ 59 ́ 03 ̋ 86 ̊ 33 ́ 43 ̋ Perry

29 Oil Creek at CR 34 near Mt. Pleasant 380629086332301 38 ̊ 06 ́ 29 ̋ 86 ̊ 33 ́ 23 ̋ Perry

30 Deer Creek at Trolly Road near Dodd 375716086393001 37 ̊ 57 ́ 16 ̋ 86 ̊ 39 ́ 30 ̋ Perry

31* Middle Fork Anderson River at SR 145

at Bristow

03303300 38 ̊ 08 ́ 20 ̋ 86 ̊ 43 ́ 16 ̋ Perry

32 Anderson River at CR 1300N near Huffman 380432086464201 38 ̊ 04 ́ 32 ̋ 86 ̊ 46 ́ 42 ̋ Spencer

33 Crooked Creek at SR 70 at Maxville 380005086511701 38 ̊ 00 ́ 05 ̋ 86 ̊ 51 ́ 17 ̋ Spencer

34 Crooked Creek at SR 245 at Lamar 380317086541801 38 ̊ 03 ́ 17 ̋ 86 ̊ 54 ́ 18 ̋ Spencer

35* Little Pigeon Creek at SR 161 near Midway 03304055 38 ̊ 00 ́ 23 ̋ 87 ̊ 10 ́ 31 ̋ Spencer

36 Cypress Creek at CR 300W–Eskew Road

near Boonville

380143087180801 38 ̊ 01 ́ 43 ̋ 87 ̊ 18 ́ 08 ̋ Warrick

37 Cypress Creek at CR 550S–Sharon Road

at Dayville

375720087195000 37 ̊ 57 ́ 15 ̋ 87 ̊ 19 ́ 51 ̋ Warrick

38 Pigeon Creek at Oak Hill Road at Evansville 375946087313001 37 ̊ 59 ́ 46 ̋ 87 ̊ 31 ́ 30 ̋ Vanderburgh

39 Pigeon Creek at First Avenue at Evansville 375944087342901 37 ̊ 59 ́ 44 ̋ 87 ̊ 34 ́ 29 ̋ Vanderburgh

40 Bayou Creek at Burdette Park near Evansville 375640087382101 37 ̊ 56 ́ 40 ̋ 87 ̊ 38 ́ 21 ̋ Vanderburgh
8 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000

posable pipets. After the samples were processed,

aluminum-block incubators were used to provide

optimum conditions for bacterial growth.

Fresh membrane-filter Thermotolerant E. coli

(mTEC) agar was prepared by personnel at the

USGS Ohio District Microbiology Laboratory.

The fresh mTEC agar was heated and poured into

petri dishes in the USGS Indiana District laboratory

for use in the field. Refrigeration units were used

to keep the mTEC agar chilled before use. The 2-

week holding time for mTEC agar, once it was

prepared, was monitored in the laboratory and field.

Urea/phenol red reagent was prepared as needed in

the USGS Indiana District laboratory and was used

to confirm the presence of E. coli colonies.

The samples collected for analysis of E. coli

were processed either in mobile laboratories set up

in hotel rooms near collection sites or in the USGS

Indiana District laboratory. Surfaces on which the

samples were processed were cleaned with isopropyl alcohol before the first sample was processed,

between samples, and after the last sample was

processed each day. Analysts washed their hands

with bactericidal soap before processing the first

sample, between samples, and after processing the

last sample.

Five to eight different sample volumes, including one to three different dilutions, were

filtered for each site because the concentration

of E. coli was unknown. A range of small to large

sample volumes and dilutions were used for processing. This was done to provide at least one

sample volume capable of producing one or more

filter plates with sufficient colony growth to achieve

the ideal E. coli colony count of 20 to 80 colonies

per filter plate (Myers and Sylvester, 1997). Stream

conditions at the time of each sampling and previous colony counts for each site obtained after the

first week of sampling guided the analysts in determining the sample quantities to process that would

help them obtain one or more filter plates in an

ideal range. Sample dilutions were made by adding

11 mL of sample water to 99 mL of sterile dilution

water for a 1:10 ratio and 1 mL of sample water

to another 99 mL of sterile dilution water for a

1:100 ratio.

Samples were shaken vigorously before each

sample dilution volume was withdrawn to ensure

uniform distribution of the bacteria throughout the

sample. Sterile, disposable 1-mL and 10-mL glass

pipets were used to measure and deliver concentrated sample volumes to dilution bottles and to

measure and deliver dilution volumes to the interior

of the funnel filter assembly. For sample dilution

volumes less than 10 mL, about 20 mL of sterile

saline buffer solution was poured into the funnel

before pipetting the sample dilution to evenly distribute the bacteria on the filter. A sterile graduated

cylinder was used to transfer sample dilution volumes greater than 10 mL. A three-port manifold

with funnels or a single-use stainless-steel filter

system was used to support a 0.45-μm (micrometer)

filter designed to facilitate colony capture, incubation, and quantification. The water was pulled

through the filter either by a vacuum pump set not

to exceed 5 lb/in2 or by a hand vacuum assembly to

prevent damage to bacteria (Myers and Sylvester,

1997, p. 10).

After filtering each of the sample dilution volumes, 20 to 30 mL of sterile saline buffer solution

were used to flush the sides of the funnel to ensure

that any bacteria present on the funnel walls were

rinsed onto the filter. The graduated cylinders used

to measure and deliver sample dilution volumes to

the funnel also were rinsed with sterile saline buffer

solution, and the rinsate was processed through the

filter.

Petri dishes containing the mTec agar used

to encourage growth of E. coli colonies on the prepared filters were labeled prior to processing the

sample. Undiluted environmental samples and sample dilutions were filtered from smallest to largest.

The filters then were placed in petri dishes with

the mTec agar and placed inverted in a pre-heated

incubator set at 35.0οC for 1.75 to 2 hours, removed, and then placed in a preheated incubator

set at 44.5οC for 22 to 24 hours. After the second

incubation period was completed, the filter was

transferred to a filter pad saturated with urea/phenol

red reagent. After 15 to 20 minutes at room temperature, the yellow to yellow-brown E. coli colonies

were counted under a microscope with magnification ranging from 7X to 10X. If the filter plate had
Study Methods 9

a colony count in the ideal range, verification of the

count was made either by the second crew member

or by rotating the filter 90 degrees and recounting

the colonies.

Concentrations of E. coli were calculated

according to the methods described by Myers and

Sylvester (1997, p. 31–33-FIB) and recorded on the

field sheet. If more than one dilution produced an

ideal colony count, the concentration of E. coli was

computed as the sum of the colony counts for each

sample volume multiplied by 100 and divided by

the sum of the sample volumes. For example, if 24

colonies were counted for a sample volume of 3 mL

and 60 colonies were counted for a sample volume

of 10 mL, the concentration of E. coli is calculated

as follows:

Col/100 mL = (24 + 60) x 100/(3 + 10) = 646, (1)

where:

Col/100 mL = colonies per 100 milliliters,

24 + 60 are the colony counts on two

different filter plates, and

3 + 10 are the sample volumes filtered

for each plate.

For this example, the result would be reported

as 650 colonies per 100 mL; whole numbers are

reported to two significant figures.

The same calculation was used if E. coli colonies were present but none of the dilutions had

concentrations of E. coli within the ideal colony

count. All the dilutions having observable colonies

present were used in the calculation, and the result

was reported as an estimate based on a non-ideal

colony count (denoted with a “K” preceding the

number). Concentrations of E. coli were reported

in whole numbers for results of less than 10, and

results greater than or equal to 10 were reported to

two significant figures (Myers and Sylvester, 1997,

p. 30-FIB). Colony counts were recorded on field

sheets labeled for each site. After counting, petri

dishes were filled with chlorine bleach, placed in

sealed plastic bags, and discarded.

Geometric Mean

The five single-sample calculations for each

site, based on either ideal or estimated (K) nonideal colony counts (whichever occurred), were

used to determine the five-sample geometric mean.

The five-sample geometric mean was calculated,

using equation 2.

(2)

where:

GM is the geometric mean, and

Si is the concentration of E. coli measured in each of the five samples.

Statistical Analysis

A Kendall’s Tau test (Helsel and Hirsch, 1992,

p. 212) for significant correlation was used to determine if there was a statistically significant

correlation between the concentration of E. coli and

turbidity. For this report, a 5-percent level of significance (α=0.05) was identified as the criterion for

the statistical correlation. The p-value is derived

from the data and measures the believability of

the null hypothesis that states no correlation exists

between concentrations of E. coli and turbidity.

The smaller the p-value, the more likely there is a

correlation between concentrations of E. coli and

turbidity and the stronger the evidence for rejection

of the null hypothesis.

A Wilcoxon signed-rank test (Helsel and

Hirsch, 1992, p. 142) was used to determine if there

were statistically significant differences between

the environmental samples and the concurrent

duplicates. The Wilcoxon signed-rank test measured whether one group of data tends to produce

larger observations than the second group and made

no assumptions regarding how the data are distributed (Helsel and Hirsch, 1992, p. 118). For this

report, a 5-percent level of significance (α=0.05)

was selected for the Wilcoxon signed-rank test.

The p-values also are presented for the Wilcoxon

signed-rank test. The smaller the p-value, the more

likely there is a difference between the environmental samples and the concurrent duplicates.

GM S1 S2 S3 S4 S5 = 5 ⋅⋅⋅⋅ ,
10 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000

Quality-Assurance Procedures

Quality-assurance procedures were followed

for collection and processing of the samples. These

procedures include frequent checking and calibration of equipment as well as collection of additional

samples for quality control. Analysis of the qualitycontrol samples provides quantitative information

not only about the potential for bias from contamination during collection and processing but also

about the variability of sampling.

The pH buffers and specific-conductance

solutions used to calibrate the multi-parameter

probe were quality assured by the USGS Quality

of Water Services Unit (QWSU). Fresh E. coli

substrate media kits were quality assured by the

USGS Ohio District Microbiology Laboratory.

Membrane filters, sterile saline buffer solution, premeasured sterile dilution water, petri dishes, and

petri dishes with pads also were quality assured by

the QWSU. The incubators were checked weekly

with an American Society for Testing and Materials

(ASTM) certified thermometer to assure that temperature ranges shown on the internal thermometer

in the incubator were accurate to ±0.5°C. The incubators were inspected daily to assure they were

operating properly.

Quality-control samples consisted of 199 filter

blanks, 54 process blanks, 15 field blanks, and 21

duplicate samples. Filter blanks were processed

before every set of samples to determine if the

equipment used to process the samples was clean

and the saline buffer solution used to rinse sampleprocessing equipment was not contaminated. While

passing the saline buffer solution through the filter,

every attempt was made to have the saline buffer

solution come in contact with every surface that

the environmental sample might touch.

Process blanks consisted of 100 mL of saline

buffer solution filtered after an environmental

sample through the same equipment used to process

environmental samples, ensuring the equipment

rinses following the filtering of each environmental

sample were adequate. Process blanks were filtered

for one sample daily.

Field blanks consisted of 250 mL of sterile

saline buffer solution that was poured into a

sample-collection bottle before personnel left

for the first sampling site for the day. The field

blanks were kept chilled and remained with the

samples collected at all sites for that day. The field

blanks were processed by passing 100 mL of the

blank solution through the filter. Duplicate samples

were collected concurrently with the environmental

samples, processed in the same manner as the environmental samples, and used to evaluate the natural

variability in the samples.

Concentrations of Escherichia coli

The Indiana Environmental Rules establish

the bacteriological quality standard for waters for

recreational uses (Oddi, 1995, 327 IAC 2-1-6 [d]).

These rules are used to evaluate waters for

full-body-contact recreational uses, to establish

wastewater-treatment requirements, and to establish effluent limits during the recreational season.

The standard states:

E. coli bacteria, using membrane filter

(MF) count, shall not exceed one hundred

twenty-five (125) per one hundred (100) milliliters as a geometric mean based on not

less than five (5) samples equally spaced

over a thirty (30) day period nor exceed two

hundred thirty-five (235) per one hundred

(100) milliliters in any one (1) sample in a

thirty (30) day period.

Concentrations of E. coli at all 40 sites, listed

in table 3 at the back of this report, ranged from

3 to 24,000 colonies per 100 mL (fig. 3), with concentrations in 72 of the 200 samples processed

exceeding the single-sample standard in samples

from 33 sites. The five-sample geometric mean

of concentrations of E. coli for all sites ranged

from 11 to 1,500 colonies per 100 mL (fig. 4). The

concentrations of E. coli in samples from 24 sites

exceeded the five-sample geometric mean standard. Concentrations of E. coli at 34 of the 40 sites

sampled exceeded either the single-sample or

the five-sample geometric mean standard(s) or

both. Concentrations of E. coli at 6 of the 40 sites

sampled did not exceed the single-sample or the

five-sample geometric mean.
23-24000

COUNTY BOUNDARY

WATERSHED BOUNDARY

EXPLANATION

e 3. Ranges in concentrations of Escherichia coli for sampling sites in the Ohio River Watershed in Indiana, May–August 2000.

26-460

74-2100

GROUP (1) ESCHERICHIA COLI SAMPLING SITES–

showing range of colonies per 100 milliliters

GROUP (2) ESCHERICHIA COLI SAMPLING SITES–

showing range of colonies per 100 milliliters

K Values estimated from non-ideal colony count 

20-4700

31-700

63-1500

77-260

32-260

K22-260

K9-150

73-790 K19-430

28-240

26-460

24-290

80-250

K19-1600 64-180

94-880

40-2800

K19-590

50-K1600

90-K13000

120-5200

160-K1600

170-7300 160-17000 310-1200

K43-170

74-2100

33-4500

45-170

150-7900

800-4400

K20-830

K3-50

22-9000

K12-67

K13-25

K60-K13000

110-1100

K10-450

39 21'

85 37'50"

0 10 20 30 40 50

0 50 KILOMETERS

MILES

om U.S. Geological Survey 1:100,000 digital data 1983

Equal Area Conic projection,

rd parallels 29 30' and 45 30', central meridian -86
100

140

67 130

420

360

280 160

250

11

490

29

17

830 450 590

430

640 430

73

700

350

1500

84

340

180

87

230

240

90

140

80

90 34 350 120

120

110

190

100

COUNTY BOUNDARY

WATERSHED BOUNDARY

EXPLANATION

4. Five-sample geometric mean Escherichia coli concentration determined for sampling sites in the Ohio River Watershed in Indiana, May–August 2000.

120

140

GROUP (1) ESCHERICHIA COLI SAMPLING SITES–

Showing five-sample geometric mean per 100 milliliters

GROUP (2) ESCHERICHIA COLI SAMPLING SITES–

Showing five-sample geometric mean per 100 milliliters

An asterisk indicates geometric mean determined by use of 

one or more samples having non-ideal colony counts

rom U.S. Geological Survey 1:100,000 digital data 1983

Equal Area Conic projection,

rd parallels 29 30' and 45 30', central meridian -86

39 21'

85 37'50"

0 10 20 30 40 50

0 50 KILOMETERS

MILES

*

*

*

*

*

* *

*

*

* *

*

*

*

* *

*

*

*

*

*
Concentrations of Escherichia coli 13

Concentrations of E. coli were examined relative to their location at sampling sites along several

stream reaches in the Ohio River Watershed in

Indiana (figs. 5 and 6). Stream reaches sampled in

May and June (Group 1 sites, fig. 5) were Laughery

and South Fork Laughery, North Hogan and South

Hogan, Grant’s, Goose, Bryant, Log Lick, Indian

(Switzerland County), and Indian-Kentuck Creeks.

Concentrations of E. coli exceeded the singlesample standard for 16 of 60 samples from Group 1.

At Laughery and South Laughery Creek (sites

1–4) and North and South Hogan Creek (sites 5 and

6), concentrations of E. coli exceeded the singlesample standard for 9 of the 30 samples collected.

Concentrations of E. coli ranged from K10 to 4,700

colonies per 100 mL. The five-sample geometric

means ranged from 90 to 240 colonies per 100 mL.

Concentrations of E. coli in Group 1 sites

(7–12) exceeded the single-sample standard for

seven of 30 samples collected at six sites. Concentrations of E. coli ranged from K9 to 790 colonies

per 100 mL. The five-sample geometric means

ranged from 34 to 350 colonies per 100 mL.

Stream reaches for Group 2 sites (fig. 6) sampled in July and August were Fourteenmile, Silver,

Indian, and Buck Creeks; Little Blue and Blue

Rivers; Little Oil, Poison, and Deer Creeks; Middle

Fork Anderson and Anderson Rivers; and Crooked,

Little Pigeon, Cypress, and Bayou Creeks. Concentrations of E. coli in 56 of 140 samples exceeded the

single-sample standard. Concentrations of E. coli

exceeded the standard for the five-sample geometric mean at 20 of the 28 sites.

Concentrations of E. coli exceeded the singlesample standard in 3 of 15 samples from two sites

on Fourteenmile Creek (sites 13 and 14) and one

site on Silver Creek (site 15). Concentrations of

E. coli ranged from K19 to 1,600 colonies per

100 mL. The five-sample geometric means ranged

from 67 to 140 colonies per 100 mL.

Concentrations of E. coli exceeded the singlesample standard for 13 of 25 samples at three of

four sites on Indian Creek (sites 16–19) and one site

on Buck Creek (site 20). Concentrations ranged

from K20 to 2,100 colonies per 100 mL. The fivesample geometric mean standard was exceeded

at the five sites, with concentrations varying from

130 to 420 colonies per 100 mL.

Concentrations of E. coli exceeded the singlesample standard in 8 of 30 samples from two sites

on the Little Blue River (sites 21 and 22) and four

sites on the Blue River (sites 23–26). Concentrations of E. coli ranged from 3 to 13,000 colonies per

100 mL. The five-sample geometric mean ranged

from 11 colonies to 340 colonies per 100 mL and

was exceeded at four of the six sites.

Concentrations of E. coli exceeded the singlesample standard in three of five samples from one

site on Little Oil Creek (site 27). Concentrations

ranged from 22 to 9,000 colonies per 100 mL. The

five-sample geometric mean was exceeded at this

site, having a concentration of E. coli of 490 colonies per 100 mL.

None of the 15 samples from sites on Poison,

Oil, and Deer Creeks (sites 2–30) exceeded the

single-sample or the five-sample geometric mean

standards. Concentrations ranged from K12 to 170

colonies per 100 mL. Concentrations for the fivesample geometric means ranged from 17 to 84

colonies per 100 mL.

All five samples from the Middle Fork Anderson River (site 31) exceeded the single-sample

and the geometric mean standards; whereas, two

of five samples from the Anderson River (site 32)

exceeded the single-sample standard, and the

five-sample geometric mean was exceeded also.

Single-sample concentrations of E. coli ranged

from 23 to 24,000 colonies per 100 mL, with the

five-sample geometric means being 1,500 colonies

per 100 mL (site 31) and 350 colonies per 100 mL

(site 32).

Twenty-two of 35 samples from two sites each

on Crooked, Cypress, and Pigeon Creeks (sites 33

and 34, 36 and 37, and 38 and 39) and one site on

Little Pigeon Creek (site 35) exceeded the singlesample standard for concentrations of E. coli.

Concentrations of E. coli ranged from 90 to 17,000

colonies per 100 mL. The five-sample geometric

means was exceeded at all sites, with concentrations of E. coli varying from 430 to 830 colonies per

100 mL.

Twenty-two of 35 samples from two sites each

on Crooked, Cypress, and Pigeon Creeks (sites 33

and 34, 36 and 37, and 38 and 39) and one site on


27 28 29 30 31 32

10

100,000

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

50,000

33 34 35 36 37 38 39 40

10

100,000

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

50,000

EXPLANATION

Five-sample geometric mean E. coli water-quality standard for full-body contact

Single-sample E. coli water-quality standard for full-body contact

Figure 6. Concentrations of Escherichia coli (E. coli) and five-sample geometric means for selected sites

 in the Ohio River Watershed in Indiana, July–August 2000—Continued.

Single-sample E. coli concentration

Five-sample geometric mean E. coli concentration

E. coli concentration based upon non-ideal colony counts

CONCENTRATION OF ESCHERICHIA COLI, IN COLONIES PER 100 MILLILITERS

 Little Oil Creek Poison Creek Oil Creek Deer Creek Middle Fork

Anderson River

 Anderson River

 Crooked Creek Cypress Creek Pigeon Creek Bayou Creek Little

Pigeon Creek
Concentrations of Escherichia coli 17

Little Pigeon Creek (site 35) exceeded the singlesample standard for concentrations of E. coli.

Concentrations of E. coli ranged from 90 to 17,000

colonies per 100 mL. The five-sample geometric

means was exceeded at all sites, with concentrations of E. coli varying from 430 to 830 colonies

per 100 mL.

None of the five samples from one site (40)

on Bayou Creek exceeded the single-sample

standard or the five-sample geometric mean.

Concentrations of E. coli ranged from K43 to 170

colonies per 100 mL. The five-sample geometric

mean was 73 colonies per 100 mL.

Relation between Concentrations of

Escherichia coli and Streamflow

The relation between concentrations of E. coli

and stream discharge was examined for five sites

at or near active USGS streamflow-gaging stations

in the Ohio River Watershed in Indiana (fig.7).

Stream discharge at the time of sample collection

was obtained from the active streamflow-gaging

stations (noted by asterisk symbols in tables 1 and

2; listed in table 3 at the back of this report) and

compared to the median daily mean discharge for

the period of record at each station. For this comparison, the median daily mean discharge is the

value for which 50 percent of the days are greater

than this discharge and 50 percent of the days are

less than this discharge for the long-term period

of record ending with the 2000 water year.

Streamflow conditions varied during the 5-

week sample-collection periods, May–June and

July–August (fig. 7). Climatic data for southern

Indiana indicated that precipitation amounts were

below normal at the beginning of water year 2000

(Stewart and others, 2001). Near the end of the

water year (June–September) when samples were

collected for this study, precipitation was above

average. On the basis of stream discharge from

the five streamflow-gaging stations, 16 percent

of the samples collected at these sites were collected at discharges above the median daily mean

discharge (Stewart and others, 2001).

Only one of the Group 1 sites, Indian-Kentuck

Creek near Canaan (fig. 7, site 12), was at or near

a streamflow-gaging station; 40 percent of the samples at that site were collected at discharges above

the long-term median daily mean discharge. Four

of the Group 2 sites (fig. 7, sites 20, 23, 26, and 31)

were at or near streamflow-gaging stations; 10 percent of the samples at those sites were collected at

discharges above the long-term median daily mean

discharge. Inspection of figure 7 indicates a general

trend of increased concentration with increased

discharge (although concentrations of E. coli can

exceed the single-sample standard during low

stream discharge and do not always exceed the

standard at discharges greater than the median

daily mean).

Relation between Concentrations of

Escherichia coli and Turbidity

To determine if there was a relation between

concentrations of E. coli and turbidity, data for

samples collected in 1998 (Silcox and others,

2000), 1999 (Silcox and others, 2001), and 2000

were combined. Turbidity is a measure of the collective optical properties of a water sample that

cause light to be scattered and absorbed rather than

transmitted in straight lines (Wilde and Gibs, 1998).

The primary contributors to turbidity include clay,

silt, fine organic and inorganic matter, plankton,

and microscopic organisms (American Public

Health Association and others, 1992). Turbidity

values measured in 1998 generally were greater

than those measured during the studies in 1999 and

2000, due in part to higher streamflow discharges

and runoff at the sites sampled in 1998. In 1998,

62 percent of the samples were collected at discharges above the long-term median daily mean

discharge, compared to 18 percent in 1999 and

16 percent in 2000.

Turbidity data are plotted with concentrations of E. coli on figure 8 for data collected in

1998, 1999, and 2000, and for 1998 through 2000.

Concentrations of E. coli exceeded the singlesample standard in 145 of 230 samples (15 percent)

collected in 1998; in 1999, 126 of 289 samples

(44 percent) exceeded the standard; and in 2000, 72


of 200 samples (36 percent) exceeded the standard.

Concentrations of E. coli exceeded the singlesample standard in 48 percent of the samples for

the 3-year period. Statistically significant correlations were determined for data collected in 1998

(p<0.001), in 2000 (p<0.001), and for the combined

3-year data set (p=0.001). There was not a statistically significant correlation between concentrations

of E. coli and turbidity in 1999.

A locally weighted scatterplot smoothing

technique (LOWESS) was used to generate the

lines in each scatterplot on figure 8. The LOWESS

method was selected to depict the relation between

turbidity and E. coli because it can accommodate

outlying data (Helsel and Hirsch, 1992, p. 48). For

data collected in 1998 and 1999, if the turbidity

was greater than 83 nephelometric turbidity units

(NTU), concentrations of E. coli in the sample

always exceeded the single-sample standard. This

was true for data collected in 2000, except for two

samples from Pigeon Creek (sites 38 and 39, listed

in table 3 at the back of this report) where the single-sample standard was not exceeded even though

the measured turbidity was greater than 83 NTU.

The analysis indicates a general relation

between concentrations of E. coli and turbidity,

whereby increased turbidity indicates increased

concentrations of E. coli. The value of turbidity

above which all samples exceed a standard is

variable and may be influenced by environmental

factors in each watershed. Turbidity and E. coli data

were collected with the same procedures for each

of the 3 years, even though the data are from watersheds with different land uses and runoff rates

 20 Concentrations of Escherichia coli, Ohio River Watershed, Indiana, May–August 2000
Concentrations of Escherichia coli 21
22 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000

and the watersheds were sampled during various

hydrologic conditions. In addition, if the measured

turbidity was less than 83 NTU, concentrations of

E. coli were not always below the single-sample

standard, indicating that factors other than turbidity

(such as soil type, land use, and the rate and duration of runoff) were affecting concentrations of

E. coli.

Quality-Assurance Results

Quality-control samples consisted of 199 filter

blanks, 54 process blanks, 15 field blanks, and 21

duplicate samples. Results of the quality-assurance

and E. coli determinations are presented in table 4

at the back of this report. Blanks and duplicate samples are discussed separately.

Filter Blanks

Filter blanks were processed for 199 of the

200 samples collected (table 4). An oversight by

the analyst resulted in a filter blank not being processed for the sample collected at site 1 on June 26.

Concentrations of E. coli in the filter blanks ranged

from 0 to 12 colonies per 100 mL. Only three of

the 199 filter blanks exhibited observable E. coli

growth—filter blanks processed for site 3 on June

27, site 10 on June 28, and site 31 on July 26. The

presence of colonies on the filter blanks indicates

a procedural error or that the glassware, the filtration equipment, and/or the saline buffer solution

used for these three samples was contaminated.

The filter blank associated with the sample from

site 3 had a concentration of 12 colonies per

100 mL of E. coli, which was approximately

11 percent of the concentration in the environmental sample. Therefore, the result reported for the

environmental sample was noted as being inconclusive. Filter blanks for samples from sites 10 and

31 contained concentrations of E. coli that were less

than one-half percent of the environmental samples,

indicating results for these samples probably are

reliable.

Process Blanks

Nineteen of the 54 process blanks contained

observable E. coli colonies. The maximum concentration of E. coli measured in the process blanks

was 12 colonies per 100 mL; the presence of

colonies indicates that the glassware or the filterholding assembly used to process the sample was

not rinsed completely or that the analyst made a

procedural error. The process blank associated with

the sample collected from site 1 on June 8 contained

a concentration of E. coli that was 18.9 percent

of the concentration in the environmental sample;

concentrations of E. coli in the remaining process

blanks were 2.5 percent or less of the concentration measured in the environmental sample. If the

concentration of E. coli in the process blank is

subtracted from the concentration in the environmental sample, in no cases would the result affect

the comparison of the environmental sample with

the water-quality standards.

Field Blanks

Fifteen field blanks were filtered during the

study on randomly selected days determined by

the analysts. Of the 15 field blanks, no E. coli colonies were present—indicating that there was no

contamination resulting from transporting the samples and that there was adequate sterilization of

the sample-collection bottles.

Duplicate Samples

Results of 21 concurrent duplicate samples

collected from 20 sites were used to evaluate the

natural variability in concentrations of E. coli for

samples collected at the same time at a site. The

natural log-percent difference between the two

samples is shown in figure 9. The median difference

between the environmental and duplicate samples

was five colonies per 100 mL. The median natural

log-percent difference between the environmental

samples and the duplicate samples was 7 percent.

A Wilcoxon signed-rank test (Helsel and Hirsch,

1992, p. 142) indicated no statistically significant

differences between the environmental samples and
Quality-Assurance Results 23
24 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000

the concurrent duplicate samples at the 5-percent

significance level. The significance level obtained

by the data, or the p-value, was 0.481.

Summary

Water samples collected from 40 stream

sites in the Ohio River Watershed in Indiana, May–

August 2000, were analyzed for concentrations of

E. coli. Five samples were collected at 12 sites

during May and June and at 28 other sites during

July and August. A five-sample geometric mean

was computed for each site. The five-sample geometric mean concentrations for all sites ranged

from 11 to 1,500 colonies per 100 mL, and concentrations at 24 sites exceeded the five-sample

geometric mean standard of 125 colonies per

100 mL. Of the 200 individual samples processed,

72 exceeded the single-sample standard of 235 colonies per 100 mL. Single-sample concentrations

of E. coli ranged from K3 to 24,000 colonies

per 100 mL during the study. The single-sample

standard and/or the five-sample geometric mean

standard for concentrations of E. coli in recreational

waters were exceeded at 34 of the 40 sites.

Five of the 40 sites were at or near USGS

streamflow-gaging stations. On the basis of records

from these stations, 16 percent of the samples

collected at these five sites were collected at streamflows above the median daily mean discharge.

Results indicate a general trend of increased concentration with increased discharge, although

concentrations of E. coli can exceed the singlesample standard during low stream discharge and

do not always exceed the standard at discharges

greater than the median daily mean.

E. coli concentration data and turbidity measurements collected in 1998 at streams within the

Upper Wabash River Watershed and in 2000 at

streams within the Ohio River Watershed showed

a statistically significant correlation. The correlation was not as strong for the 1999 data collected

in streams within the Kankakee and Lower Wabash

River Watersheds but, overall, the combined data

set for the 3 years was statistically significant.

The concentration of E. coli always exceeded

the single-sample standard when the turbidity

exceeded 83 NTU for the studies in 1998 and

1999 and the majority of sample concentrations for

the study in 2000. There were two occurrences in

2000 when the measured turbidity was greater than

83 NTU, but the single-sample standard for concentrations of E. coli was not exceeded. In contrast,

when the measured turbidity was less than 83 NTU,

concentrations of E. coli were not always below the

single-sample standard.

References Cited

American Public Health Association and others, 1992, in

National field manual for the collection of waterquality data: U.S. Geological Survey Techniques of

Water-Resources Investigations, book 9, chap. 6.7,

p. 3.

American Public Health Association, American Water

Works Association, and Water Pollution Control

Federation, 1992, Standard methods for the examination of water and wastewater (18th ed.), Parts

9221 through 9225: Washington, D.C., American

Public Health Association, p. 9–1 to 9–73.

Bordner, Robert, and Winter, J.A., 1978, Microbiological methods for monitoring the environment, water,

and wastes: U.S. Environmental Protection Agency,

EPA 600/8-78-017, 338 p.

Britton, L.J., and Greeson, P.E., eds., 1989, Methods

for collection and analysis of aquatic biological and

microbiological samples: U.S. Geological Survey

Techniques of Water-Resources Investigations,

book 5, chap. A4, 160 p.

Fenelon, Joseph M., Bobay, Keith E., and others,

1994, Hydrogeologic atlas of aquifers in Indiana:

U.S. Geological Survey Water-Resources Investigations Report 92-4142, 197 p.

Francy, Donna S., Myers, Donna N., and Helsel, Dennis

R., 2000, Microbiological monitoring for the

U.S. Geological Survey National Water-Quality

Assessment Program: U.S. Geological Survey

Water Resources Investigations Report 00-4018,

34 p.

Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in water resources: Studies in Environmental

Science, no. 49, New York, Elsevier Publishers,

Inc., 522 p.
References Cited—Continued 25

References Cited—Continued

Indiana Department of Environmental Management,

2000, Indiana Water Quality Report 2000: From

URL http; www.state.in.us/idem/owm/planbr/wqs/

quality.html accessed September 28, 2001.

Myers, D.N., and Sylvester, M.A., 1997, Fecal indicator

bacteria, in National field manual for the collection

of water-quality data: U.S. Geological Survey Techniques of Water-Resources Investigations, book 9,

chap. 7.1, p. FIB 1-38.

Oddi, M.J., ed., 1995, Indiana environmental rules—

Water: Indiana Department of Environmental

Management, p. 19.

Schneider, A.F., 1966, Physiography, in Lindsey, A.A.,

ed., Natural features of Indiana: Indianapolis, Indiana Academy of Science and Indiana State Library,

p. 40–56.

Silcox, C.A., Robinson, B.A., and Willoughby, T.C.,

2001, Concentrations of Escherichia coli in

streams in the Kankakee and Lower Wabash River

Watersheds in Indiana, June–September, 1999:

U.S. Geological Water-Resources Investigations

Report 01-4018, 58 p.

Silcox, C.A., Voelker, D.C., and Willoughby, T.C.,

2000, Concentrations of Escherichia coli in

the upper Wabash River Watershed in Indiana,

June–September, 1998: U.S. Geological Survey

Water-Resources Investigations Report 00-4021,

52 p.

Stewart, J.A., Keeton, C.R., Hammil, L.E., Nguyen,

H.T., and Majors, D.K., 2001, Water resources

data, Indiana, water year 2000: U.S. Geological

Survey Water-Data Report IN-01-1, 450 p.

Wilde, F.D., and Gibs, Jacob, 1998, Turbidity, in

National field manual for the collection of waterquality data: U.S. Geological Survey Techniques of

Water Resources Investigations, book 9, chap. 6.7,

p. 3.

Supplemental Data

(Tables 3 and 4)
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000

[--, no data; >, K, non-ideal colony count; date is month-day-year, time is in military notation]

28 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 Site number Date Time Gage height1 (feet) Discharge at time of sample collection (cubic feet per second) Water temperature (degrees Celsius) pH (Standard units) Dissolved oxygen (milligrams per liter) Specific conductance (microsiemens per centimeter at 25 degrees Celsius) Tu

(Neph

turbid

1 05-30-00 1230 70.50 -- 18.0 7.6 8.1 375 41 06-08-00 1150 69.74 -- 20.0 8.1 10.0 448 11 06-12-00 1126 69.64 -- 25.0 8.2 12.5 449 1 06-19-00 1120 70.96 -- 19.5 7.4 6.9 309 111 06-26-00 1045 70.00 -- 24.5 7.9 7.4 438 3

Five-sample geometric mean 

2 05-31-00 1125 81.50 -- 21.0 7.9 9.0 299 62 06-06-00 1530 81.00 -- 23.0 9.0 15.1 294 12 06-13-00 1138 80.70 -- 26.5 8.2 8.0 339 12 06-20-00 1240 81.74 -- 22.0 7.8 8.0 309 82 06-27-00 1141 81.05 -- 24.5 8.2 8.8 338 1

Five-sample geometric mean 

3 05-31-00 1000 67.10 -- 21.0 7.7 7.5 301 73 06-06-00 1430 65.50 -- 22.5 8.4 12.1 388 13 06-13-00 0955 65.84 -- 25.5 7.5 7.9 359 13 06-20-00 1055 66.40 -- 21.5 7.7 7.0 331 83 06-27-00 0947 65.95 -- 26.0 8.1 9.3 398 2

Five-sample geometric mean 

4 05-31-00 1035 68.10 -- 20.5 8.3 11.6 458 4 06-06-00 1340 67.80 -- 20.0 8.1 11.4 479 4 06-13-00 1028 67.69 -- 24.0 8.0 8.1 343 4 06-20-00 1145 68.38 -- 21.5 8.1 9.1 423 4 06-27-00 1015 68.00 -- 23.0 8.0 8.2 460 

Five-sample geometric mean 
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

Water-Quality Data 29

5 05-30-00 1335 79.50 -- 18.5 8.1 10.6 440 5 06-05-00 1455 79.20 -- 21.5 8.0 7.3 457 5 06-12-00 1223 79.06 -- 26.5 7.9 7.2 484 5 06-19-00 1225 79.51 -- 20.0 8.0 8.5 356 25 06-26-00 1140 79.10 -- 25.5 8.0 6.7 411 1

Five-sample geometric mean 

6 05-30-00 1430 77.40 -- 20.0 8.5 11.1 394 6 06-05-00 1545 77.05 -- 22.5 8.4 9.9 407 6 06-12-00 1357 76.76 -- 24.5 8.4 10.5 421 6 06-19-00 1405 74.70 -- 22.0 8.2 9.0 354 46 06-26-00 1225 76.45 -- 25.5 8.5 12.1 434 

Five-sample geometric mean 

7 05-31-00 0900 77.70 -- 19.0 7.9 8.6 492 7 06-06-00 1110 77.53 -- 20.0 7.8 7.5 487 7 06-13-00 0841 77.57 -- 24.0 7.4 3.4 532 7 06-20-00 0940 77.75 -- 19.5 8.1 8.9 464 7 06-27-00 0847 77.74 -- 23.5 7.9 7.5 491 

Five-sample geometric mean 

8 06-01-00 0840 78.80 -- 24.0 8.0 7.7 385 38 06-07-00 1040 78.28 -- 22.5 8.1 7.9 379 38 06-14-00 0847 78.69 -- 27.5 8.3 9.0 384 28 06-21-00 0915 78.93 -- 24.5 7.6 5.8 313 58 06-28-00 0856 78.40 -- 25.5 7.7 5.2 339 5

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Tu

(Neph

turbid
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

30 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 9 06-01-00 0950 86.20 -- 22.0 7.8 6.3 447 2

9 06-07-00 1115 85.94 -- 20.0 7.6 5.0 446 29 06-14-00 0925 86.36 -- 26.0 7.6 3.4 448 19 06-21-00 1105 86.37 -- 21.5 7.8 6.8 434 29 06-28-00 0930 86.10 -- 23.0 7.6 4.0 458 2

Five-sample geometric mean 

10 06-01-00 1020 87.90 -- 20.5 7.7 6.6 520 110 06-07-00 1230 87.80 -- 17.5 6.7 7.6 548 110 06-14-00 0952 87.73 -- 22.5 7.7 4.7 584 10 06-21-00 1135 88.10 -- 22.0 7.7 6.9 481 110 06-28-00 1020 87.95 -- 21.0 7.7 6.8 504 1

Five-sample geometric mean 

11 06-01-00 1105 58.50 -- 20.5 7.7 6.3 398 211 06-07-00 1445 50.86 -- 20.5 7.6 6.7 484 111 06-14-00 1030 51.10 -- 24.5 7.6 4.9 514 111 06-21-00 1310 56.79 -- 22.5 7.8 7.4 417 111 06-28-00 1105 50.60 -- 22.0 7.6 6.4 444 2

Five-sample geometric mean 

12 05-30-00 1535 2.96 10.4 22.0 8.4 11.3 398 12 06-05-00 1656 2.73 3.2 22.5 8.2 10.3 408 12 06-12-00 1510 2.52 .8 28.0 7.8 9.1 453 12 06-19-00 1515 3.29 28 22.5 8.1 8.9 436 112 06-26-00 1400 2.79 5.5 25.5 8.2 12.4 452 

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Tu

(Neph

turbid
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

Water-Quality Data 31

13 07-10-00 1100 71.78 -- 27.0 8.3 12.1 401 13 07-17-00 1205 71.87 -- 28.0 8.3 12.2 377 13 07-24-00 1145 71.87 -- 24.5 8.3 11.1 374 13 07-31-00 1153 71.99 -- 23.5 7.7 7.2 241 113 08-07-00 1230 71.83 -- 26.0 8.4 11.8 342 

Five-sample geometric mean 

14 07-10-00 1135 59.09 -- 26.0 7.8 7.4 397 14 07-17-00 1255 59.04 -- 26.5 7.9 7.6 383 14 07-24-00 1220 59.16 -- 24.5 7.8 7.5 303 14 07-31-00 1130 59.44 -- 24.0 7.9 7.7 266 14 08-07-00 1300 59.06 -- 25.5 7.7 6.9 306 

Five-sample geometric mean 

15 07-10-00 1340 71.43 -- 26.5 8.2 9.3 617 115 07-17-00 1355 71.10 -- 27.5 7.9 7.3 528 115 07-24-00 1255 70.65 -- 25.5 7.9 8.0 752 115 07-31-00 1300 70.72 -- 26.0 7.9 7.5 900 115 08-07-00 1330 71.49 -- 26.5 8.0 8.0 753 1

Five-sample geometric mean 

16 07-10-00 1430 75.18 -- 26.0 7.6 8.9 332 16 07-17-00 1450 74.42 -- 24.5 7.6 7.5 337 16 07-24-00 1345 74.84 -- 22.5 7.6 8.0 357 16 07-31-00 1345 74.93 -- 24.0 7.6 7.0 334 16 08-07-00 1405 74.82 -- 25.0 7.3 6.5 344 

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Tu

(Neph

turbid
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

32 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 17 07-10-00 1535 71.95 -- 24.5 7.9 8.4 393 

17 07-17-00 1535 71.75 -- 23.0 7.7 8.2 400 17 07-24-00 1420 71.56 -- 22.0 7.7 8.9 401 17 07-31-00 1415 71.82 -- 21.0 7.4 6.2 421 217 08-07-00 1450 71.65 -- 24.5 7.6 6.1 371 

Five-sample geometric mean 

18 07-12-00 1405 91.52 -- 28.0 8.1 8.5 417 18 07-19-00 1225 92.58 -- 24.5 7.9 7.6 508 318 07-26-00 1215 92.32 -- 29.5 8.2 11.2 576 18 08-02-00 1110 92.72 -- 27.0 8.2 9.7 399 118 08-09-00 1130 93.48 -- 24.5 7.8 9.2 395 2

Five-sample geometric mean 

19 07-12-00 1035 71.60 -- 26.0 7.8 7.8 406 19 07-19-00 1025 70.43 -- 25.0 7.4 4.0 421 119 07-26-00 1010 69.68 -- 22.5 7.4 4.0 447 119 08-02-00 0935 70.93 -- 23.5 7.4 2.5 433 19 08-09-00 1005 72.82 -- 24.5 7.4 3.1 405 1

Five-sample geometric mean 

20 07-12-00 1300 1.69 13.3 25.0 8.0 8.6 377 20 07-19-00 1135 1.84 18.1 23.5 7.8 7.1 351 20 07-26-00 1100 1.73 4.9 21.5 7.8 7.8 354 20 08-02-00 1025 1.83 6.2 23.0 7.9 6.9 378 20 08-09-00 1055 1.85 7.7 24.0 7.8 8.1 357 

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Tu

(Neph

turbid
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

Water-Quality Data 33

21 07-11-00 1030 65.90 -- 26.0 7.5 5.2 556 21 07-18-00 1130 65.76 -- 25.0 7.4 5.3 664 121 07-26-00 1030 66.05 -- 21.5 7.4 5.5 841 121 08-01-00 1000 66.10 -- 22.5 7.4 5.3 567 421 08-08-00 1010 66.03 -- 24.5 7.4 4.9 823 1

Five-sample geometric mean 

22 07-11-00 0920 67.00 -- 28.0 8.0 8.9 299 22 07-18-00 1035 67.30 -- 27.0 7.6 6.4 336 122 07-25-00 0930 66.95 -- 24.5 7.3 4.1 340 122 08-01-00 0910 67.20 -- 24.5 7.3 2.8 323 22 08-08-00 0925 67.65 -- 26.5 7.7 7.0 332 

Five-sample geometric mean 

23 07-11-00 1440 2.29 35 24.5 7.9 8.6 409 123 07-18-00 1430 2.11 22 24.5 8.0 9.6 440 23 07-25-00 1325 2.33 39 21.0 8.0 9.7 447 23 08-01-00 1305 2.77 91 22.5 7.9 7.5 405 223 08-08-00 1320 2.38 44 22.5 7.8 7.4 431 2

Five-sample geometric mean 

24 07-11-00 1130 79.08 -- 25.0 7.9 8.0 418 24 07-18-00 1220 79.00 -- 23.5 7.9 7.1 434 24 07-25-00 1125 79.03 -- 21.5 7.9 7.9 404 124 08-01-00 1050 79.42 -- 20.0 7.5 6.8 361 724 08-08-00 1110 79.02 -- 24.0 7.8 6.5 410 

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Tu

(Neph

turbid
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

34 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 25 07-11-00 1240 70.97 -- 26.0 8.2 9.9 400 

25 07-18-00 1330 70.99 -- 27.0 8.3 10.3 401 25 07-25-00 1210 71.11 -- 23.0 8.1 9.4 321 125 08-01-00 1155 71.94 -- 24.0 8.1 8.3 422 125 08-08-00 1210 71.06 -- 24.5 8.0 7.8 407 

Five-sample geometric mean 

26 07-12-00 0900 66.72 110 24.0 7.7 6.7 434 26 07-19-00 0930 66.58 82 23.5 7.8 6.8 450 26 07-26-00 0850 66.50 66 21.5 7.7 7.0 386 126 08-02-00 0845 67.31 247 23.0 7.8 7.2 454 26 08-09-00 0915 67.65 374 21.5 7.5 7.8 488 1

Five-sample geometric mean 

27 07-10-00 1250 67.92 -- 24.5 7.1 2.7 281 127 07-17-00 1242 67.70 -- 24.5 7.2 2.1 320 27 07-24-00 1532 68.01 -- 22.5 7.3 2.2 307 127 07-31-00 1405 67.56 -- 23.0 7.2 2.5 279 227 08-07-00 1330 68.19 -- 25.0 7.2 3.4 260 1

Five-sample geometric mean 

28 07-10-00 1343 78.20 -- 23.0 7.1 .7 301 28 07-17-00 1355 77.90 -- 22.5 7.2 3.2 333 28 07-24-00 1615 78.28 -- 21.0 7.2 .9 315 28 07-31-00 1450 77.71 -- 22.5 7.2 2.6 306 128 08-07-00 1420 78.34 -- 23.5 7.1 2.3 277 

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Tur

(Neph

turbid
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

Water-Quality Data 35

29 07-10-00 1210 71.90 -- 25.0 7.5 7.1 305 129 07-17-00 1205 71.80 -- 25.5 7.7 7.3 335 129 07-24-00 1412 71.83 -- 21.5 7.5 5.2 326 129 07-31-00 1250 71.95 -- 22.5 7.3 4.5 321 129 08-07-00 1230 71.85 -- 25.0 7.4 5.1 289 

Five-sample geometric mean 

30 07-10-00 1440 85.72 -- 24.0 7.0 1.7 244 30 07-17-00 1506 85.43 -- 24.0 7.1 2.7 266 30 07-24-00 1701 85.88 -- 22.0 7.1 2.0 260 30 07-31-00 1540 85.62 -- 23.0 7.1 2.5 258 30 08-07-00 1520 85.77 -- 24.0 7.1 2.0 242 

Five-sample geometric mean 

31 07-12-00 1147 6.72 5.9 26.0 7.0 3.3 186 231 07-19-00 1055 6.59 3.1 25.0 7.0 3.7 165 431 07-26-00 1202 6.52 2.3 22.0 7.0 4.7 158 231 08-02-00 1250 6.44 1.2 25.0 6.9 2.5 216 131 08-09-00 1210 7.04 16 25.0 7.0 5.9 149 2

Five-sample geometric mean 

32 07-12-00 1105 72.74 -- 25.0 7.0 2.3 292 132 07-19-00 1005 72.57 -- 23.5 7.1 2.2 297 32 07-26-00 1120 72.53 -- 20.5 7.1 1.9 318 32 08-02-00 1155 72.82 -- 23.0 7.1 4.0 264 132 08-09-00 1125 75.85 -- 23.0 6.7 4.5 131 29

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Tu

(Neph

turbid
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

36 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 33 07-12-00 1009 67.05 -- 25.5 7.3 3.9 457 1

33 07-19-00 0930 67.00 -- 24.5 7.3 3.0 458 433 07-26-00 1030 67.03 -- 22.5 7.4 4.9 445 133 08-02-00 1055 67.10 -- 23.5 7.3 4.0 632 133 08-09-00 1045 67.99 -- 24.0 7.0 3.6 277 27

Five-sample geometric mean 

34 07-12-00 0925 79.40 -- 26.0 7.0 1.3 462 534 07-19-00 0900 79.55 -- 25.0 7.2 2.9 549 934 07-26-00 0950 79.33 -- 21.5 7.2 2.3 736 434 08-02-00 0950 79.30 -- 24.5 7.6 8.8 513 334 08-09-00 1010 79.95 -- 24.0 6.9 2.8 357 6

Five-sample geometric mean 

35 07-12-00 0835 71.97 -- 26.0 7.5 4.3 1,800 235 07-19-00 0815 71.90 -- 25.5 7.6 4.7 2,000 235 07-26-00 0855 71.70 -- 22.0 7.6 5.6 2,000 235 08-02-00 0905 76.41 -- 23.0 6.8 4.2 391 535 08-09-00 0910 78.14 -- 23.5 6.8 5.4 302 21

Five-sample geometric mean 

36 07-11-00 1243 83.71 -- 26.5 8.3 12.0 1,700 136 07-18-00 1230 83.75 -- 29.5 8.1 9.8 1,900 136 07-25-00 1458 83.73 -- 29.5 8.7 -- 1,900 36 08-01-00 1530 83.84 -- 28.0 7.5 7.8 1,600 236 08-08-00 1325 84.24 -- 25.0 7.4 6.5 1,400 7

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Tur

(Neph

turbid
Table 3. Water-quality data for selected sites in the Ohio River Watershed in Indiana, May–August 2000—Continued

Water-Quality Data 37 1Gage height number is either from a gage recorder or computed by subtracting the tape down value measured from a fixed point on a bridge from an arbitrary 

37 07-11-00 1205 75.37 -- 27.5 8.0 6.5 1,800 60 37 07-18-00 1105 75.27 -- 27.5 8.1 8.5 1,900 33 37 07-25-00 1425 75.14 -- 27.0 8.3 13.0 2,000 24 37 08-01-00 1450 76.53 -- 26.5 7.7 7.7 1,300 55 37 08-08-00 1300 75.90 -- 25.0 7.6 6.5 1,400 39 

Five-sample geometric mean 

38 07-11-00 1107 64.92 -- 26.5 7.5 2.6 1,300 25 38 07-18-00 1030 64.68 -- 26.0 7.6 3.3 1,500 50 38 07-25-00 1228 64.80 -- 23.0 7.7 4.3 1,900 50 38 08-01-00 1250 68.83 -- 23.0 7.4 5.1 880 180 38 08-08-00 1045 71.32 -- 23.5 6.9 3.8 212 280 

Five-sample geometric mean 

39 07-11-00 1025 55.57 -- 26.0 7.6 4.2 1,100 29 39 07-18-00 0950 56.43 -- 25.5 7.6 4.3 1,300 20 39 07-25-00 1141 55.25 -- 22.5 7.6 5.8 1,700 339 08-01-00 1135 56.54 -- 22.5 7.4 5.4 846 270 39 08-08-00 1030 61.15 -- 23.5 6.9 4.1 186 440 

Five-sample geometric mean 

40 07-11-00 0942 96.57 -- 28.0 7.0 .4 412 440 07-18-00 0900 96.58 -- 26.0 7.0 .6 463 440 07-25-00 1010 96.61 -- 23.0 7.2 1.2 489 540 08-01-00 0950 96.73 -- 24.5 7.1 1.9 479 940 08-08-00 0940 96.80 -- 26.5 7.0 1.7 449 9

Five-sample geometric mean 

Site

number Date Time

Gage

height1

(feet)

Discharge

at time

of sample

collection

(cubic feet

per second)

Water

temperature

(degrees

Celsius)

pH

(Standard

units)

Dissolved

oxygen

(milligrams

per liter)

Specific

conductance

(microsiemens

per centimeter at

25 degrees

Celsius)

Turb

(Nephe

turbidi
Table 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River Watershed in Indiana, Ma

[K, non-ideal colony count; --, no data]

38 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 Site number Date Time Environmental sample (colonies per 100 milliliters) Filter blank Process blank Field blank Concurrent duplicate Escherichia coli (colonies per 100 milliliters) 

1 05-30-00 1230 490 0 -- -- -- 1 06-08-00 1150 53 0 10 -- 56 1 06-12-00 1126 20 0 -- -- -- 1 06-19-00 1120 4,700 0 -- -- -- 1 06-26-00 1045 310 -- -- -- -- 2 05-31-00 1125 170 0 0 -- 87 2 06-06-00 1530 62 0 0 0 -- 2 06-13-00 1138 K22 0 -- -- -- 2 06-20-00 1240 260 0 0 -- -- 2 06-27-00 1141 K100 0 -- -- -- 3 05-31-00 1000 31 0 -- -- -- 3 06-06-00 1430 74 0 -- -- -- 3 06-13-00 0955 67 0 -- -- -- 3 06-20-00 1055 700 0 -- -- -- 3 06-27-00 0947 K110 12 -- -- -- 4 05-31-00 1035 110 0 -- -- -- 4 06-06-00 1340 77 0 -- -- -- 4 06-13-00 1028 110 0 0 -- 100 4 06-20-00 1145 260 0 -- -- -- 4 06-27-00 1015 210 0 1 -- -- 5 05-30-00 1335 150 0 -- -- -- 5 06-05-00 1455 100 0 -- -- -- 5 06-12-00 1223 K10 0 -- -- -- 5 06-19-00 1225 450 0 -- -- -- 5 06-26-00 1140 260 0 -- -- -- 
Table 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River Watershed in Indiana, May

Quality-Assurance Data 39

6 05-30-00 1430 200 0 -- -- 180 6 06-05-00 1545 63 0 -- -- -- 6 06-12-00 1357 170 0 -- -- -- 6 06-19-00 1405 1,500 0 -- -- -- 6 06-26-00 1225 76 0 -- -- -- 7 05-31-00 0900 59 0 -- -- -- 7 06-06-00 1110 32 0 -- -- -- 7 06-13-00 0841 52 0 -- -- -- 7 06-20-00 0940 260 0 -- 0 -- 7 06-27-00 0847 120 0 -- -- -- 8 06-01-00 0840 K80 0 -- 0 -- 8 06-07-00 1040 K13 0 -- -- -- 8 06-14-00 0847 K9 0 -- -- -- 8 06-21-00 0915 150 0 -- -- 248 8 06-28-00 0856 K32 0 -- -- -- 9 06-01-00 0950 67 0 -- -- -- 9 06-07-00 1115 K19 0 -- -- -- 9 06-14-00 0925 120 0 0 -- -- 9 06-21-00 1105 430 0 -- -- -- 9 06-28-00 0930 K93 0 -- -- -- 

10 06-01-00 1020 790 0 0 -- -- 10 06-07-00 1230 170 0 0 -- 103 10 06-14-00 0952 73 0 -- -- 68 10 06-21-00 1135 770 0 0 -- -- 10 06-28-00 1020 660 3 -- -- -- 

Site number Date Time

Environmental sample

(colonies per

100 milliliters)

Filter

blank

Process

blank

Field

blank

Concurrent

duplicate

Escherichia coli

(colonies per

100 milliliters)

N
Table 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River Watershed in Indiana, May

40 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 11 06-01-00 1105 240 0 -- -- -- 

11 06-07-00 1445 28 0 -- -- -- 11 06-14-00 1030 220 0 -- -- -- 11 06-21-00 1310 200 0 -- -- -- 11 06-28-00 1105 72 0 -- -- K73 12 05-30-00 1535 100 0 0 -- -- 12 06-05-00 1656 26 0 -- -- -- 12 06-12-00 1510 87 0 0 0 -- 12 06-19-00 1515 460 0 0 -- 460 12 06-26-00 1400 K210 0 0 0 -- 13 07-10-00 1100 24 0 -- -- -- 13 07-17-00 1205 160 0 0 0 -- 13 07-24-00 1145 110 0 -- 0 -- 13 07-31-00 1153 290 0 -- 0 -- 13 08-07-00 1230 100 0 -- 0 -- 14 07-10-00 1135 180 0 -- -- -- 14 07-17-00 1255 110 0 0 -- -- 14 07-24-00 1220 120 0 -- -- -- 14 07-31-00 1130 80 0 -- -- -- 14 08-07-00 1300 250 0 -- -- -- 15 07-10-00 1340 35 0 -- -- K50 15 07-17-00 1355 1,600 0 3 -- -- 15 07-24-00 1255 K35 0 -- -- -- 15 07-31-00 1300 K19 0 -- -- -- 15 08-07-00 1330 K36 0 -- -- -- 

Site number Date Time

Environmental sample

(colonies per

100 milliliters)

Filter

blank

Process

blank

Field

blank

Concurrent

duplicate

Escherichia coli

(colonies per

100 milliliters)

N
Table 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River Watershed in Indiana, May

Quality-Assurance Data 41

16 07-10-00 1430 110 0 -- -- -- 16 07-17-00 1450 64 0 1 -- -- 16 07-24-00 1345 170 0 -- -- -- 16 07-31-00 1345 160 0 1 -- -- 16 08-07-00 1405 180 0 -- -- -- 17 07-10-00 1535 400 0 0 -- -- 17 07-17-00 1535 74 0 1 -- -- 17 07-24-00 1420 260 0 1 -- -- 17 07-31-00 1415 2,100 0 5 -- -- 17 08-07-00 1450 800 0 1 -- -- 18 07-12-00 1405 K56 0 -- -- -- 18 07-19-00 1225 4,500 0 1 -- -- 18 07-26-00 1215 33 0 -- -- K25 18 08-02-00 1110 690 0 0 -- -- 18 08-09-00 1130 1,100 0 12 -- -- 19 07-12-00 1035 240 0 -- -- -- 19 07-19-00 1025 710 0 -- -- -- 19 07-26-00 1010 40 0 -- -- -- 19 08-02-00 0935 K20 0 -- -- K19 19 08-09-00 1005 830 0 -- -- -- 20 07-12-00 1300 250 0 0 0 -- 20 07-19-00 1135 1,100 0 -- -- -- 20 07-26-00 1100 110 0 -- -- -- 20 08-02-00 1025 230 0 -- -- -- 20 08-09-00 1055 240 0 -- -- -- 

Site number Date Time

Environmental sample

(colonies per

100 milliliters)

Filter

blank

Process

blank

Field

blank

Concurrent

duplicate

Escherichia coli

(colonies per

100 milliliters)

N
Table 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River Watershed in Indiana, May

42 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 21 07-11-00 1030 220 0 -- -- -- 

21 07-18-00 1130 62 0 0 -- -- 21 07-26-00 1030 K60 0 -- -- -- 21 08-01-00 1000 K13,000 0 -- -- -- 21 08-08-00 1010 93 0 -- -- K140 22 07-11-00 0920 K3 0 -- -- -- 22 07-18-00 1035 50 0 0 -- -- 22 07-25-00 0930 K7 0 -- -- -- 22 08-01-00 0910 K7 0 -- -- -- 22 08-08-00 0925 K20 0 -- -- -- 23 07-11-00 1440 170 0 0 -- -- 23 07-18-00 1430 94 0 0 -- -- 23 07-25-00 1325 450 0 1 -- -- 23 08-01-00 1305 760 0 1 -- -- 23 08-08-00 1320 880 0 1 -- -- 24 07-11-00 1130 110 0 -- -- -- 24 07-18-00 1220 40 0 1 -- 49 24 07-25-00 1125 170 0 -- -- -- 24 08-01-00 1050 2,800 0 -- -- -- 24 08-08-00 1110 97 0 -- -- -- 25 07-11-00 1240 74 0 -- -- -- 25 07-18-00 1330 K19 0 0 -- -- 25 07-25-00 1210 56 0 -- -- -- 25 08-01-00 1155 590 0 -- -- -- 25 08-08-00 1210 110 0 -- -- -- 

Site number Date Time

Environmental sample

(colonies per

100 milliliters)

Filter

blank

Process

blank

Field

blank

Concurrent

duplicate

Escherichia coli

(colonies per

100 milliliters)

N
Table 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River Watershed in Indiana, May

Quality-Assurance Data 43

26 07-12-00 0900 50 0 -- -- 40 26 07-19-00 0930 520 0 -- -- -- 26 07-26-00 0850 78 0 -- -- -- 26 08-02-00 0845 190 0 -- -- -- 26 08-09-00 0915 K1,600 0 -- -- -- 27 07-10-00 1250 310 0 -- -- -- 27 07-17-00 1242 22 0 0 0 -- 27 07-24-00 1532 9,000 0 -- 0 -- 27 07-31-00 1405 6,700 0 -- 0 -- 27 08-07-00 1330 67 0 -- -- -- 28 07-10-00 1343 35 0 0 -- K8 28 07-17-00 1355 21 0 -- -- -- 28 07-24-00 1615 K12 0 0 -- -- 28 07-31-00 1450 K34 0 0 -- -- 28 08-07-00 1420 67 0 -- -- -- 29 07-10-00 1210 77 0 -- -- -- 29 07-17-00 1205 45 0 -- -- -- 29 07-24-00 1412 170 0 0 -- -- 29 07-31-00 1250 70 0 -- -- -- 29 08-07-00 1230 100 0 -- -- 48 30 07-10-00 1440 25 0 -- -- -- 30 07-17-00 1506 K14 0 -- -- -- 30 07-24-00 1701 K14 0 -- -- -- 30 07-31-00 1540 K21 0 -- -- -- 30 08-07-00 1520 K13 0 -- 0 -- 

Site number Date Time

Environmental sample

(colonies per

100 milliliters)

Filter

blank

Process

blank

Field

blank

Concurrent

duplicate

Escherichia coli

(colonies per

100 milliliters)

N
Table 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River Watershed in Indiana, May

44 Concentrations of Escherichia coli in Streams in the Ohio River Watershed in Indiana, May–August 2000 31 07-12-00 1147 810 0 -- -- -- 

31 07-19-00 1055 4,400 0 -- -- -- 31 07-26-00 1202 800 1 1 -- -- 31 08-02-00 1250 2,000 0 0 -- 2,442 31 08-09-00 1210 1,500 0 1 -- -- 32 07-12-00 1105 140 0 -- -- -- 32 07-19-00 1005 450 0 0 -- -- 32 07-26-00 1120 23 0 -- -- -- 32 08-02-00 1155 140 0 -- -- -- 32 08-09-00 1125 24,000 0 -- -- -- 33 07-12-00 1009 260 0 0 -- -- 33 07-19-00 0930 1,200 0 -- -- -- 33 07-26-00 1030 150 0 0 -- -- 33 08-02-00 1055 190 0 -- -- -- 33 08-09-00 1045 7,900 0 -- -- -- 34 07-12-00 0925 280 0 -- 0 -- 34 07-19-00 0900 700 0 -- -- 1,267 34 07-26-00 0950 90 0 -- -- -- 34 08-02-00 0950 740 0 -- -- -- 34 08-09-00 1010 K13,000 0 -- -- -- 35 07-12-00 0835 200 0 -- -- -- 35 07-19-00 0815 260 0 -- -- -- 35 07-26-00 0855 120 0 -- -- -- 35 08-02-00 0905 570 0 -- -- -- 35 08-09-00 0910 5,200 0 -- -- -- 

Site number Date Time

Environmental sample

(colonies per

100 milliliters)

Filter

blank

Process

blank

Field

blank

Concurrent

duplicate

Escherichia coli

(colonies per

100 milliliters)

N
Table 4. Quality-assurance data associated with Escherichia coli samples collected in the Ohio River Watershed in Indiana, May

Quality-Assurance Data 45

36 07-11-00 1243 1,200 0 0 -- 316 36 07-18-00 1230 1,200 0 -- -- -- 36 07-25-00 1458 310 0 0 -- -- 36 08-01-00 1530 990 0 0 -- -- 36 08-08-00 1325 900 0 5 -- -- 37 07-11-00 1205 830 0 -- -- -- 37 07-18-00 1105 210 0 -- -- -- 37 07-25-00 1425 160 0 2 -- -- 37 08-01-00 1450 310 0 -- -- -- 37 08-08-00 1300 K1,600 0 -- -- -- 38 07-11-00 1107 17,000 0 -- -- -- 38 07-18-00 1030 160 0 -- -- -- 38 07-25-00 1228 190 0 -- -- -- 38 08-01-00 1250 910 0 -- -- -- 38 08-08-00 1045 K230 0 -- -- -- 39 07-11-00 1025 250 0 -- -- -- 39 07-18-00 0950 170 0 -- -- -- 39 07-25-00 1141 230 0 -- -- 177 39 08-01-00 1135 200 0 -- -- -- 39 08-08-00 1030 7,300 0 -- -- -- 40 07-11-00 0942 K84 0 -- -- -- 40 07-18-00 0900 170 0 0 -- -- 40 07-25-00 1010 K47 0 -- -- -- 40 08-01-00 0950 K43 0 -- -- -- 40 08-08-00 0940 73 0 -- -- -- 

Site number Date Time

Environmental sample

(colonies per

100 milliliters)

Filter

blank

Process

blank

Field

blank

Concurrent

duplicate

Escherichia coli

(colonies per

100 milliliters)

N