U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2010–5036

In cooperation with Bowling Green State University and the Wood County Health Department

Utility of Microbial Source-Tracking Markers for Assessing 

Fecal Contamination in the Portage River Watershed, 

Northwestern Ohio, 2008

Utility of Microbial Source-Tracking 

Markers for Assessing Fecal 

Contamination in the Portage River 

Watershed, Northwestern Ohio, 2008

By Christopher M. Kephart and Rebecca N. Bushon

In Cooperation With Bowling Green State University and the 

Wood County Health Department

Scientific Investigations Report 2010–5036

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Suggested citation:

Kephart, C.M., and Bushon, R.N., 2010, Utility of microbial source-tracking markers for assessing fecal contamination 

in the Portage River watershed, northwestern Ohio, 2008: U.S. Geological Survey Scientific Investigations Report 

2009–5036, 7 p.
iii

Contents

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

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

Methods...........................................................................................................................................................2

Utility of Microbial Source-Tracking Markers for Assessing Fecal Contamination...........................4

Summary and Conclusions...........................................................................................................................6

References......................................................................................................................................................7

Figures

1. Location of sampling sites within the Portage River watershed, 

northwestern Ohio........................................................................................................................3

Tables

1. Sampling site locations and descriptions.................................................................................2

2. Standard-curve characteristics for AllBac, BoBac, Btheta, and qHF183 

microbial source-tracking (MST) markers ...............................................................................4

3. DNA marker results for fecal source samples collected on November 6, 2007, 

Portage River watershed, northwestern Ohio.........................................................................5

4. DNA marker results for water samples, Portage River watershed, 

northwestern Ohio........................................................................................................................5
iv

Conversion Factors

Multiply By To obtain

Volume

milliliter (mL) 0.06102 cubic inch (in3)

milliliter (mL) 0.03381 fluid ounce (oz)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32
Utility of Microbial Source-Tracking Markers for 

Assessing Fecal Contamination in the Portage River 

Watershed, Northwestern Ohio, 2008

By Christopher M. Kephart and Rebecca N. Bushon

Abstract

An influx of concentrated animal feeding operations in 

northwest Ohio has prompted local agencies to examine the 

effects of these industrial farms on water quality in the upper 

Portage River watershed. The utility of microbial sourcetracking (MST) tools as a means of characterizing sources of 

fecal contamination in the watershed was evaluated. From 

2007 to 2008, scientists with the U.S. Geological Survey, 

Bowling Green State University, and the Wood County Health 

Department collected and analyzed 17 environmental samples 

and 13 fecal source samples for Bacteroides-based hostassociated DNA markers. At many of the environmental sites 

tested, MST marker results corroborated the presumptive fecal 

contamination sources. Results from this demonstration study 

support the utility of using MST with host-specific molecular 

markers to characterize the sources of fecal contamination in 

the Portage River watershed.

Introduction

The upper Portage River watershed in northwestern Ohio 

is an agricultural area whose water quality has historically 

been influenced by runoff from row crops and small-scale 

livestock operations and discharges from septic systems and 

small wastewater-treatment plants. Recently, however, the area 

has been targeted for construction and operation of large dairy 

farms. As of July 2007, two large-scale dairies already were 

operating, and three more were proposed. Local officials and 

the public are concerned that discharges from these animal 

feeding operations (AFOs) will result in the degradation of 

water quality. Little information is available, however, on the 

influence of existing fecal sources on water quality (including 

the two large-scale dairies) within the watershed. 

In order to establish current (2008) or baseline conditions 

before any watershed protection steps are undertaken, the relative contributions of contaminants from AFOs, septic systems, 

and treated wastewater within the Portage River watershed 

need to be understood. Contaminants include pathogens of 

fecal origin, wastewater compounds (including hormones 

and antibiotics), nutrients, and suspended sediment. Research 

indicates that the best approach for characterizing the sources 

of fecal contamination in a watershed is to establish multiple lines of evidence (Boehm and others, 2003; Francy 

and others, 2006). This is done by identifying the spatial 

distribution of bacterial and chemical indicators, understanding the hydrologic factors that affect their distribution, and 

applying microbial source-tracking (MST) techniques. The 

use of culture-independent host-specific molecular markers is 

gaining acceptance among researchers as the preferred MST 

tool (Santo Domingo and others, 2007). Molecular markers 

for MST are common in research; however, their utility for 

forensic assessment of fecal sources in a specific location must 

be demonstrated before being applied.

The U.S. Geological Survey (USGS), in cooperation 

with Bowling Green State University (BGSU) and the Wood 

County Health Department (WCHD), have taken the first 

step towards understanding the relative contributions of fecal 

contaminants by identifying the source-tracking tools that 

can best be used in the Portage River watershed. Fecal source 

and environmental water samples were analyzed for Bacteroides DNA markers of general fecal contamination, as well 

as markers that have been associated with human or bovine 

feces. The Bacteroides are the most numerous members of 

the normal flora of the human intestinal system (Finegold and 

others, 1983) and are a group of enteric bacteria thought to 

have co-evolved with their hosts (Dick and others, 2005). For 

these reasons, their host specificity has been investigated for 

use in microbial source tracking (Bernhard and Field, 2000). 

In this study, samples were analyzed by means of quantitative 

polymerase chain reaction (qPCR), which results in a relative quantity of each DNA marker. The results from this study 

may be used as preliminary information for a larger, long-term 

source-tracking study to identify and assess relative source 

contributions of fecal contamination in the changing Portage 

River watershed. 

This report documents the demonstration study to identify MST tools that can be used to understand the relative contributions of fecal contaminant sources in the Portage River 
2 Microbial Source-Tracking Markers for Assessing Fecal Contamination, Portage River Watershed, Northwestern Ohio

watershed. A total of 17 environmental water samples and 

13 known-source fecal samples (treated wastewater, septage, 

and bovine slurry) were tested for the presence and relative 

quantity of MST markers by qPCR. Four Bacteroides-based 

markers were evaluated: two human-associated MST markers, 

one bovine-associated MST marker, and one marker of general 

fecal contamination.

Methods

Fecal source sampling.—Sample collection of potential 

fecal sources (treated wastewater, septage, and cattle slurry) 

was done on November 6, 2007, by USGS, BGSU, and 

WCHD to ensure that the selected DNA markers were found 

in potential sources. These samples consisted of 

• two wastewater samples (primary-treated influent and 

final effluent) collected from two treatment plants in 

or near the watershed (designated as WWTP-1 and 

WWTP-2),

• septic-tank samples collected from six households in 

the watershed,

• two replicate cattle-slurry samples collected from the 

primary settling lagoon at a local dairy farm, and

• a composite goose fecal sample collected from a golf 

course in the watershed to confirm that human or 

bovine-associated markers would not be detected.

Wastewater, septage, and bovine slurry samples 

were collected in sterile polypropylene bottles by using a 

grab-sampling technique described in Myers and others 

(2007). A total of 20 individual goose fecal droppings were 

composited into a sterile 50-mL centrifuge tube using sterile 

toothpicks. All source samples were preserved on ice and were 

transported to the USGS for further analysis.

Water sampling.—Water samples were collected on June 

26, 2008, and September 15, 2008, at the sites described in 

table 1 and illustrated in figure 1. The June samples, which 

were collected by USGS and BGSU, were collected after 

a recent rain event. The September samples were collected 

by BGSU. Samples were collected in sterile polypropylene 

bottles by using a grab-sampling technique described in Myers 

and others (2007). All water samples were preserved on ice 

and were transported to BGSU and USGS for further analysis.

Sample analyses.—Fecal source samples were analyzed 

by the USGS within 24 hours of collection by membrane 

filtration on modified mTEC agar (U.S. Environmental Protection Agency, 2006). Water samples were analyzed for E. coli

by BGSU within 24 hours of collection by means of a mostprobable number (MPN) technique using Colilert in QuantiTray/2000 wells (Idexx, Westbrook, Maine). At USGS, all 

samples were filtered and stored at −70°C for subsequent DNA 

marker analysis. All samples were analyzed for three Bacteroides DNA markers; fecal source samples were also analyzed 

for a fourth marker (Btheta): 

• General fecal marker, AllBac (Layton and others, 2006)

• Human fecal marker, qHF183 (Seurnick and others, 

2005)

• Bovine fecal marker, BoBac (Layton and others, 2006)

• Human fecal marker, Btheta (Carson and others, 2005)

Table 1. Sampling site locations and descriptions.

[WWTP, wastewater-treatment plant; BGSU, Bowling Green State University; WCHD, Wood County Health Department]

Site name Latitude Longitude Site descriptiona

Poe Ditch 1 41.38513 −83.61185 Upstream from WWTP

Poe Ditch 2 41.38511 −83.61086 Downstream from WWTP

Huffman Ditch 41.33953 −83.59162 Thought to have septic inputs

Unnamed Tile 1 41.24818 −83.77061 Field with no manure application

Unnamed Tile 2 41.24817 −83.77083 Field with possible manure application

Unnamed Tile 3 41.25075 −83.76598 Field with no manure application

Bays Ditch 1 41.26963 −83.73242 Thought to drain manure-applied field

Bays Ditch 2 41.26461 −83.72824 Thought to drain manure-applied field and have septic inputs

Bays Tile 1 41.26963 −83.73100 Thought to drain manure-applied field

Bays Tile 2 41.26962 −83.72825 Thought to have septic inputs

Ostego Pike Ditch 41.24782 −83.78533 Mixed sources

Rangeline Ditch 41.28486 −83.76642 Not expected to have high levels of fecal contamination

a

Descriptions are based on presumptions, input from local agencies, and historical data collected by BGSU and WCHD. Discussions of possible sources 

are based only on observations, not on scientific evidence.
Methods 3

Bays Tile 1 Bays Tile 2

Poe Ditch 2 Poe Ditch 1

Bays Ditch 2

Bays Ditch 1

Huffman Ditch

Rangeline Ditch

Unnamed Tile 3

Unnamed Tile 2

Unnamed Tile 1

Ostego

Pike Ditch

83°45' 83°40' 83°35'

41°20' 41°15'

0 1 2 Miles

0 1 2 Kilometers

EXPLANATION

Sampling locations

Stream network

Roads

Lake Erie

OHIO Portage River watershed

LUCAS CO

WOOD CO

OTTAWA CO

SANDUSKY CO

SENECA CO

HANCOCK CO

Portage River

watershed

Middle

Branch

Middle

Branch

North

BranchBranch

PortagePortage

River

PortagePortage

River

Bowling Green

Figure 1. Location of sampling sites within the Portage River watershed, northwestern Ohio. 
4 Microbial Source-Tracking Markers for Assessing Fecal Contamination, Portage River Watershed, Northwestern Ohio

Quantitative PCR.—Quantification was done by use of 

standard curves calculated from threshold cycles observed for 

decimal dilutions of plasmid-borne DNA target. Calculation 

of standard concentrations was based on the total concentration of DNA in the plasmid solution and the known size of 

the target-containing plasmid. Characteristics of the standard 

curves are presented in table 2.

Each qPCR run included a standard curve, an extraction 

blank (negative control at the extraction step), and a no-template control (negative control at the qPCR step). The upper 

and lower limits of quantification (ULQ and LLQ, represented 

as the dynamic range in table 2) were based on the range of 

standards that contributed to the linear part of the standard 

curve. In all cases, the standard curve remained linear at both 

the highest and lowest standards.

No-template-control and extraction-blank data were 

used to measure a limit of detection (LOD). The no-template 

controls and extraction blanks sometimes showed nonspecific 

fluorescent signal during late cycles. In these cases, the mean 

and the 99-percent confidence interval among cycle thresholds 

were calculated. To guard against false-positive results, the target concentration that corresponded with detection at the lower 

99-percent confidence interval of multiple detections was used 

as the LOD. A cycle threshold higher than the LOD was not 

considered credible evidence that the sample contained detectable quantities of the marker.

The LLQ and the LOD were used to qualify low-concentration data. In cases where the LLQ was greater than the 

LOD, results higher than the LLQ were not qualified. Results 

between the LLQ and the LOD were qualified “detected, not 

quantified” (DNQ). Results below the LOD were considered 

nondetects. Conversely, when the LOD was greater than the 

LLQ, results higher than the LOD were not qualified. Results 

below the LOD were considered nondetects.

Exogenous internal standard.—DNA encoding redfluorescent protein dsRed2 (Matz and others, 1999) was used 

as an internal standard that is not expected to be detected from 

natural sources in the freshwater environment. Approximately 

2.5×106 cells of E. coli containing a dsRed2 plasmid were 

added to each filtered sample immediately before extraction. 

Recovery of dsRed2 marker was measured by qPCR and used 

as a measure of matrix inhibition. Cycle threshold values of 

all samples were within 2 cycles of the expected Ct value for 

the positive control and thus were not considered to be matrix 

inhibited.

Utility of Microbial Source-Tracking 

Markers for Assessing Fecal 

Contamination

A total of 13 fecal source samples and 17 water samples 

were analyzed for DNA markers. Tables 3 and 4 list the results 

for the source and water samples, respectively. These tables 

show the quantities of the markers, in copies per 100 milliliters, which were based on multiple runs of composite standard 

curves of known concentrations of each marker. 

Table 2. Standard-curve characteristics for AllBac, BoBac, Btheta, and qHF183 microbial source-tracking (MST) 

markers.

[R2, Pearson correlation coefficient; ND, not detected]

MST marker Number of compiled curves

Dynamic range

(copies per 

100 milliliters)

Range of amplification 

efficiency (percent) Range of R2

 values

Limit of detection

(copies per 

100 milliliters)

AllBac 11 1.2×101–1.2×107 82–102 0.985–0.999 290

BoBac 11 6.1×101 – 6.1×107 82–101 0.992–0.999 NDa

Btheta 4 5.7×101 – 5.7×107 84–91 0.992–0.999 NDa

qHF183 23 2.3×101 – 2.3×107 84–108 0.991–1.000 NDb

a

The marker was never detected in a blank.

b

The marker was detected in one of 10 blanks; however, it was considered an outlier and was removed from the dataset because it was 

atypical and the replicate result was not detected.
Utility of Microbial Source-Tracking Markers for Assessing Fecal Contamination 5

Table 3. DNA marker results for fecal source samples collected on November 6, 2007, Portage River watershed, 

northwestern Ohio.

[WWTP, wastewater-treatment plant; ND, not detected; DNQ, detected but not quantified; --, not analyzed for]

Sample namea

Escherichia coli 

(colony-forming 

units per 

100 milliliters)

Marker concentration (copies per 100 milliliters)

AllBac 

general marker

BoBac

bovine marker

Btheta

human marker

qHF183

human marker

WWTP-1 influent 7.6×105 1.3×108 1.4×104 2.7×104 3.7×106

WWTP-1 effluent 3.0×102 4.0×103 ND DNQ 4.5×101

WWTP-2 influent 9.8×105 2.3×108 9.9×103 7.2×104 2.9×106

WWTP-2 effluent 1.0×103 3.5×103 ND DNQ 4.8×102

Septic 1 9.8×105 7.9×108 ND 1.7×103 8.4×105

Septic 2 <1.0×103 3.4×108 ND DNQ 6.0×105

Septic 3 2.1×105 2.6×108 ND 1.1×103 2.4×102

Septic 4 1.0×103 3.8×108 ND DNQ DNQ

Septic 5 2.9×104 4.6×108 ND 1.9×103 1.1×105

Septic 6 4.6×104 1.5×108 ND 6.5×103 5.8×105

Cattle 1 9.1×106 3.7×109 1.1×108 DNQ DNQ

Cattle 2 -- 2.5×109 5.5×107 DNQ ND

Goose -- 1.1×107 ND DNQ ND

a

 Sample names defined in methods section.

Table 4. DNA marker results for water samples, Portage River watershed, northwestern Ohio.

[ND, not detected; DNQ, detected but not quantified]

Date Sample name

Escherichia coli 

 (most-probable

number per 

100 milliliters)

Marker concentration (copies per 100 milliliters)

AllBac 

general marker

BoBac

bovine marker

qHF183 

human marker

6/26/2008 Poe Ditch 1 7.7×103 5.7×106 1.5×103 1.0×103

9/15/2008 Poe Ditch 1 2.1×103 5.0×106 6.2×102 8.4×103

6/26/2008 Poe Ditch 2 4.0×102 1.7×107 9.8×103 4.7×104

9/15/2008 Poe Ditch 2 2.8×103 8.8×106 3.0×103 5.6×104

6/26/2008 Huffman Ditch 1.7×104 1.5×108 3.0×104 1.8×105

9/15/2008 Huffman Ditch 3.3×102 2.9×106 DNQ 1.4×102

6/26/2008 Unnamed Tile 1 3.8×102 1.7×106 DNQ DNQ

6/26/2008 Unnamed Tile 2 3.7×103 5.2×106 2.8×103 DNQ

9/15/2008 Unnamed Tile 2 2.3×103 1.0×106 DNQ DNQ

9/15/2008 Unnamed Tile 3 2.8×102 1.1×106 ND DNQ

6/26/2008 Bays Ditch 1 2.9×103 2.2×106 2.3×102 9.6×102

9/15/2008 Bays Ditch 1 3.8×103 1.7×106 ND DNQ

6/26/2008 Bays Ditch 2 6.9×103 2.6×106 DNQ 2.2×103

9/15/2008 Bays Tile 1 2.1×102 6.5×105 ND DNQ

9/15/2008 Bays Tile 2 1.6×104 1.3×107 9.7×102 1.1×104

6/26/2008 Ostego Pike Ditch 6.1×103 1.5×106 DNQ 1.1×102

6/26/2008 Rangeline Ditch 6.2×102 5.4×105 ND DNQ
6 Microbial Source-Tracking Markers for Assessing Fecal Contamination, Portage River Watershed, Northwestern Ohio

Fecal source samples.—The AllBac general fecal marker 

was detected in all 13 fecal source samples at concentrations ranging from 3.5×103

 to 3.7×109 copies per 100 milliliters. The BoBac bovine-associated marker was detected at 

high concentrations, as expected, in the two cattle samples; 

however, it also was detected at considerably lower levels in 

both wastewater-influent samples. The BoBac marker was not 

detected in any of the six septic-source samples. The Btheta 

human-associated marker was detected at quantifiable levels 

in only 6 of the 10 human-source samples; it was detected at 

levels below the LLQ in 4 human-source samples and all of 

the non-human samples (2 cattle and 1 goose). Because the 

Btheta marker was detected in nonhuman sources, it does 

not appear to be a useful human-associated marker for use in 

this study; consequently, stream samples were not analyzed 

for this marker. The qHF183 human marker was detected at 

quantifiable levels in 9 of the 10 human-source samples and 

was detected in the remaining human-source sample, but at a 

nonquantifiable level. This marker also was detected in one of 

the cattle samples but at a level below the LLQ. 

Water samples.1—In the Poe Ditch 1 samples, collected 

upstream from a WWTP outfall, concentrations of AllBac, 

BoBac, and qHF183 were lower on both collection dates 

than in Poe Ditch 2 samples, collected downstream from the 

WWTP outfall. At Poe Ditch 2, the concentrations of BoBac 

and qHF183 markers were among the highest observed in the 

water samples collected during this study. High levels of the 

qHF183 were expected at Poe Ditch 2 because qPCR analysis 

detects genetic targets regardless of cell viability. According 

to personnel at this WWTP, possible sources of bovine-origin 

fecal contamination at these Poe Ditch sites include drainage 

that goes to the WWTP from nearby county fairground lands 

and combined-sewer overflow (CSO) events flowing into Poe 

Ditch upstream from Poe Ditch 2 after heavy rain. (Heavy 

rainfall before the June sample may have led to contribution 

of fairground drainage and/or a CSO event to Poe Ditch at this 

site). 

The Huffman Ditch site was expected to receive inputs 

from upstream septic sources. This expectation was corroborated by its having the highest concentration of qHF183 

observed in this study (in the June sample). This sample, 

which was collected after a significant rain event, also had the 

highest concentrations of E. coli, AllBac, and BoBac. The high 

BoBac concentration was unexpected because adjacent fields 

were not known to receive manure application. This finding 

demonstrates that other sources of fecal contamination may be 

influencing this site, especially after rainfall. 

The Unnamed Tile 1 and 3 sites were known to drain 

fields that do not receive cattle-manure application; results 

show concentrations of BoBac and qHF183 that were either 

below the LLQ or not detected. Unnamed Tile 2 was thought 

to drain a cattle-manure-treated field; results show a detectable 

concentration of BoBac in the June sample. The fact that the 

1

 Names of ditches in this report are unofficial and follow the local convention of reference to the adjoining road name. 

September sample collected at Unnamed Tile 2 had a BoBac 

concentration below the LLQ was not unexpected because 

flow from the tile was very low, and at least 2 months had 

elapsed since the last cattle manure application.

Before sampling, there was less confidence in the 

presumptions about the inputs of contamination to the Bays 

Ditch and Bays Tile sites than at the other sites. Concentrations of the BoBac and qHF183 markers generally were low, 

if detected, with the exception of high levels of qHF183 in the 

Bays Tile 2 site, which was thought to have septic inputs. 

The Ostego Pike Ditch sample was thought to be affected 

by both human and animal sources of contamination. The 

BoBac marker was detected below the LLQ, and the qHF183 

marker was detected at a low concentration. 

The Rangeline Ditch site was included to serve as a control site and was not expected to have high levels of contamination. The concentration of the AllBac marker was the lowest 

measured in the stream samples for this study. The BoBac 

marker was not detected in this sample, and the qHF183 

marker was detected at levels below the LLQ. 

The results described above suggest that microbial source 

tracking by means of host-associated molecular markers is a 

viable option for characterizing fecal contamination sources in 

the upper Portage River watershed. With the exception of the 

Btheta marker, the markers tested exhibited good host specificity, based on analysis of known-source fecal samples. In addition, marker results for most ditch and tile sites were reflective 

of expected fecal sources. This study provides a foundation 

from which future investigations could be conducted concerning fecal contamination in the Portage River watershed. 

In addition to demonstrating usefulness of these MST methods, this study provides background information on putative 

sources and sites that may be helpful in future investigations 

in the watershed.

Summary and Conclusions

Water-quality impacts to the Portage River watershed 

originate from a variety of sources, including various agricultural operations, septic-system discharges, and wastewatertreatment-plant (WWTP) effluent. Recent and planned expansion of industrial livestock operations, such as large-scale 

dairy farms, in and surrounding the watershed has prompted 

concern about the possible effects on water quality. Characterization of the sources of fecal contamination was undertaken 

in 2008 to assist water-resource managers in determination of 

the most effective watershed protection steps to take. Along 

with the Wood County Health Department and Bowling Green 

State University, the U.S. Geological Survey investigated the 

usefulness of microbial source tracking (MST) with host-associated molecular markers to characterize cattle and humanorigin fecal contamination in the Portage River watershed. 

Of the three host-associated MST markers evaluated, 

two markers—BoBac (bovine-associated) and qHF183 
References 7

(human-associated)—performed well enough during analysis 

of relevant fecal samples to be considered for evaluation of 

water samples. For many of the water-sampling locations, 

observations and input from local agencies were provided 

about what fecal inputs could be affecting water quality. At 

many of these sites, BoBac and qHF183 marker results supported the presumptive fecal inputs. At Poe Ditch, samples 

collected downstream from WWTP effluent had increased 

levels of qHF183 compared to samples collected upstream 

from the effluent. At Huffman Ditch, the presumption of 

septic-dominant inputs was corroborated by elevated levels of 

qHF183 but was complicated by concurrently elevated levels 

of BoBac. At the Unnamed Tile sites, all drainage samples 

from fields not expected to receive manure application had 

levels of BoBac that were undetected or below the lower limit 

of quantitation (LLQ). Conversely, the BoBac marker was 

detected at quantifiable levels from the drainage tile of a field 

known to receive manure applications. At a site expected to 

receive minimal fecal contamination, Rangeline Ditch, marker 

results were either undetected or below the LLQ.

Results from this study demonstrate the utility of using 

microbial source tracking with host-associated markers to 

help characterize fecal contamination sources in the Portage 

River watershed. Future studies to investigate contamination 

sources could include use of the BoBac and qHF183 markers, 

along with other new or refined MST markers that have been 

validated for use in the watershed. If expansion of large-scale 

or industrial livestock facilities continues in this watershed, 

then host-associated MST marker analysis can potentially be 

a useful tool in elucidating fecal contamination sources and 

pathways, and could provide water-resource managers and 

public health officials with data needed for effective watershed 

protection.

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