Escherichia coli and Microbial Source Tracking Marker 

Concentrations in and Near a Constructed Wetland in 

Maumee Bay State Park, Oregon, Ohio, 2015–16

Prepared in cooperation with the University of Toledo Prepared in cooperation with the University of Toledo

Escherichia coli and Microbial Source Tracking Marker 

Concentrations in and Near a Constructed Wetland in 

Maumee Bay State Park, Oregon, Ohio, 2015–16

Scientific Investigations Report 2018–5127

U.S. Department of the Interior

U.S. Geological Survey
Cover: Photo of wetland adjacent to Berger Ditch, Oregon, Ohio, July 8, 2015, photograph by Christopher Kephart, U.S. Geological Survey.

Back cover: Photo of wetland adjacent to Berger Ditch, Oregon, Ohio, February 3, 2016, photograph by Christopher Kephart, U.S. Geological 

Survey.
Escherichia coli and Microbial Source 

Tracking Marker Concentrations in and 

Near a Constructed Wetland in Maumee 

Bay State Park, Oregon, Ohio, 2015–16

By Christopher M. Kephart, Amie M.G. Brady, and Ryan W. Jackwood

Prepared in cooperation with the University of Toledo

Scientific Investigations Report 2018–5127

U.S. Department of the Interior

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

DAVID BERNHARDT, Acting Secretary

U.S. Geological Survey

James F. Reilly II, Director

U.S. Geological Survey, Reston, Virginia: 2019

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–ASK–USGS.

For an overview of USGS information products, including maps, imagery, and publications, 

visit https://store.usgs.gov.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Kephart, C.M., Brady, A.M.G., and Jackwood, R.W., 2019, Escherichia coli and microbial source tracking marker concentrations in and near a constructed wetland in Maumee Bay State Park, Oregon, Ohio, 2015–16: U.S. Geological 

Survey Scientific Investigations Report 2018–5127, 13 p., https://doi.org/10.3133/sir20185127.

ISSN 2328-0328 (online)
iii

Contents

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

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

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

Site Descriptions and Sampling Frequency .....................................................................................2

Rainfall and Streamflow Data.............................................................................................................2

Sampling Procedures...........................................................................................................................2

Laboratory Analyses and Associated Laboratory Quality Control ...............................................4

Escherichia coli Analysis ...........................................................................................................4

Microbial Source Tracking Marker Analyses .........................................................................4

DNA Extraction and qPCR Analyses................................................................................4

Standard Curves and Quantifying Microbial Source Tracking Markers ...................4

Quality Control Measures of Variability and Bias.....................................................................................5

Escherichia coli and Microbial Source Tracking Marker Concentrations at Selected Sites 

Entering Maumee Bay, Lake Erie...................................................................................................5

Summary..........................................................................................................................................................8

References Cited............................................................................................................................................8

Appendix 1. Concentrations of Escherichia coli and microbial source tracking markers at 

Berger Ditch, wetland, and Maumee Bay sites, Oregon, Ohio, 2015–16 ..............................10
iv

Figures

1. Map showing location of sample collection sites in Maumee Bay State Park,

Oregon, Ohio, 2015–16..................................................................................................................3

2. Boxplots showing concentrations of the general marker GenBac and

Escherichia coli during dry- and wet-weather sampling conditions Maumee

Bay State Park, Oregon, Ohio, 2015–16.....................................................................................6

Tables

1. Standard curve characteristics and limits of detection and quantification for

microbial source tracking markers............................................................................................4

2. Quality-control concurrent replicate data for Escherichia coli and microbial

source tracking markers, Maumee Bay State Park, Oregon, Ohio, 2014–16......................5

3. Summary statistics for detections of host-associated microbial source

tracking markers in samples collected at Maumee Bay State Park, Oregon,

Ohio, 2015–16.................................................................................................................................7

Conversion Factors

U.S. customary units to International System of Units

Multiply By To obtain

Length

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

yard (yd) 0.9144 meter (m)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

cubic inch (in3) 0.01639 liter (L)

inch per year per foot ([in/yr]/ft) 83.33 millimeter per year per meter 

([mm/yr]/m)

Datum

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).
v

Supplemental Information

Concentrations of Escherichia coli (E. coli) in water are reported as most probable number per 

100 milliliters (MPN/100 mL) or as colony-forming units per 100 milliliters (CFU/100 mL).

Microbial source tracking markers are reported as copies per 100 milliliters.

Abbreviations

CFU Colony-forming unit

USEPA U.S. Environmental Protection Agency

FIB Fecal indicator bacteria

LoB Limit of blanks

LoD Limit of detection

LoQ Limit of quantification

MBSP Maumee Bay State Park

MST Microbial source tracking

OWML Ohio Water Microbiology Laboratory

qPCR Quantitative polymerase chain reaction

SRL Sample reporting limit

USGS U.S. Geological Survey

Escherichia coli and Microbial Source Tracking Marker

Concentrations in and Near a Constructed Wetland in

Maumee Bay State Park, Oregon, Ohio, 2015–16 

By Christopher M. Kephart1

, Amie M.G. Brady1, and Ryan W. Jackwood2

Abstract

Elevated Escherichia coli (E. coli) concentrations at 

the Maumee Bay State Park (MBSP) Lake Erie beach have 

resulted in frequent recreational water-quality advisories. After 

the construction of a wetland along Berger Ditch in Maumee 

Bay State Park, Oregon, Ohio, samples were collected and 

analyzed for concentrations of E. coli and microbial source 

tracking (MST) markers. This study was done by the U.S. 

Geological Survey, in cooperation with the University of 

Toledo, to provide data that can be used to help evaluate the 

effects of the wetland on water quality in MBSP. From July 

2015 to February 2016, 116 samples were collected from six 

sites. Median GenBac (general marker) and E. coli concentrations were higher in samples from Berger Ditch sites than in 

samples from the wetland sites. No statistically significant 

difference was found between median E. coli concentrations in samples collected at Berger Ditch sites upstream and 

downstream from the wetland. The frequency of detection 

of the human-associated Bacteroides MST marker (HF183) 

decreased from 39 percent upstream from the wetland to 

22 percent downstream from the wetland; however, the 

HF183 median concentrations from these two groups of 

samples were nearly the same (2,700 to 2,800 copies per 

100 milliliters from upstream to downstream). The waterfowlassociated Helicobacter MST marker (GFD) was detected in 

13 percent of samples from the Berger Ditch site upstream 

from the wetland, although it was not detected in samples 

from the Berger Ditch site downstream from the wetland. The 

ruminant-associated MST marker, Rum2Bac, was not detected 

at any site during this study.

1

U.S. Geological Survey.

2

University of Toledo.

Introduction

Exposure to microbiological pathogens in water contaminated by human and animal feces poses a significant human 

health risk (World Health Organization [WHO], 2003). The 

U.S. Environmental Protection Agency (USEPA, 2012) has 

developed bacterial water-quality criteria to protect recreational water users from exposure to pathogens (such as bacteria, viruses, and protozoa) at concentrations likely to cause 

illness. These criteria are based on concentrations of fecal 

indicator bacteria (FIB), such as Escherichia coli (E. coli) and 

enterococci, which are used to estimate the potential occurrence of pathogens. FIB generally are nonpathogenic and 

ubiquitous in human and animal feces. Standard methods used 

to determine concentrations of FIB do not provide information 

about the source of contamination (Boehm and others, 2009 

and 2013); therefore, other techniques are used to supplement 

FIB monitoring data to help identify FIB contributions from 

human sources. Human-source FIB are of particular concern 

because they are expected to pose a higher risk to public 

health than sources of non-human origin (WHO, 1999 and 

2003; Colford and others, 2007; Soller and others, 2010).

Microbial source tracking (MST) can be used to identify 

and characterize dominant sources of FIB in a water body, 

thereby enabling water managers to implement source-appropriate remediation strategies to improve water quality. There 

are currently no standard methods for MST. One of the most 

commonly used MST methods uses quantitative polymerase 

chain reaction (qPCR) to detect and enumerate molecular 

markers; however, no one single method has been identified as 

the best method for determining sources.

Sources of bacterial contamination contributing to recreational water at Maumee Bay State Park Lake Erie beach in 

Oregon, Ohio, are not well-characterized. Runoff from fields 

where biosolids have been applied and septic system failures 

in the watershed may be contributing to high levels of fecal 

contamination. Effluent from drainage tiles in fields where 

biosolids have been applied as fertilizer are known to flow to 

Wolf Creek and Berger Ditch. Waterfowl, including Larus spp. 
2 E. coli and Microbial Tracking Marker Concentrations at Constructed Wetland in Maumee Bay State Park, OH., 2015–16

(gulls) and Branta canadensis (Canada geese), are also potential contributors of fecal contamination to recreational water at 

Maumee Bay State Park Lake Erie beach.

In the summer of 2015, a novel wetland was constructed 

to demonstrate and quantify the ability of ecosystem services 

to reduce nutrients and fecal microorganisms in Berger Ditch. 

Concentrations of E. coli elevated above background conditions are frequently detected in water at the Maumee Bay State 

Park Lake Erie beach, leading to beach advisories (Francy and 

others, 2013; https://ny.water.usgs.gov/maps/nowcast/). Berger 

Ditch, which discharges to Lake Erie just east of the beach, 

has previously been characterized as having an important 

effect on water quality at and near the beach (Francy and others, 2005).

This report describes the results of research done by 

the U.S. Geological Survey (USGS), in cooperation with the 

University of Toledo, to evaluate the effects of a constructed 

wetland on selected microbiological water-quality constituents 

in Berger Ditch and Maumee Bay State Park Lake Erie beach. 

This research is part of a larger effort by the University of 

Toledo to evaluate the effectiveness of that wetland and other 

restoration efforts, including a restored floodplain for Wolf 

Creek. A total of 116 samples were collected from six sites 

from July 2015 to February 2016 and analyzed for concentrations of E. coli and several MST markers (general Bacteroides— human-, waterfowl-, and ruminant-associated). The 

results are presented in this report.

Methods of Study

Site Descriptions and Sampling Frequency

With a drainage area of approximately 16 square 

miles (mi2), Berger Ditch flows from south to north and empties into Maumee Bay in Lake Erie 230 feet (ft) east of the 

Maumee Bay State Park (MBSP) Lake Erie beach (fig. 1). 

Berger Ditch receives flow from Wolf Creek (not shown) 

which drains 10.7 mi2

. Land use surrounding Berger Ditch and 

Wolf Creek consists primarily of farmland and single-family 

residences.

Adjacent to Berger Ditch to the west is the wetland 

designed by the University of Toledo. The wetland is 

hydraulically connected to Berger Ditch by a holding pond 

(3,000 square meters [m2] x 3 m [32,292 ft2 x 9.84 ft] in 

depth). From this holding pond, water is pumped through subsurface distribution pipes into the first of three subsurface flow 

wetland cells (each 2,800 m2

 [30,139 ft2] in area). The wetland 

cells were constructed by excavating soil and backfilling 0.6 m 

(1.97 ft) of limestone gravel and 0.1 m (0.328 ft) of coarse 

aggregate, topped with 0.2 m (0.656 ft) of on-site topsoil. 

The wetland cells were designed as a cascading system where 

elevation decreases by 0.3 m (0.984 ft) between each cell, 

allowing water to passively flow from the first through the 

third cell and then to Berger Ditch. Water flows through the 

subsurface gravel of each wetland cell until entering collection pipes that direct flow between wetland cells. This process 

is repeated until water is discharged into Berger Ditch and 

continues toward Maumee Bay. Water-level control structures 

(WLCSs) provide access for water-sample collection prior to 

the first wetland cell (WLCS-1), between the first and second 

wetland cells (WLCS-2), between the second and third wetland cells (WLCS-3), and between the third wetland cell and 

Berger Ditch (WLCS-4). The retention time for the wetland at 

the time of this study was calculated to be 2.1 days. This calculation was based on the void space within the wetland cells 

and the pumping rate from the holding pond.

Sampling was done at six sites as part of this study 

(fig. 1). Generally, samples were collected twice per week—

Monday and Wednesday—for 12 weeks. In Berger Ditch, one 

site (W1) is upstream from the wetland adjacent to the USGS 

streamgage (station number 04194085). Three sampling sites 

are within the wetland at WLCS-1 (W2), WLCS-3 (W4), and 

WLCS-4 (W5). Samples were collected at site W4 instead 

of site W5 when WLCS-4 was submerged in overflow water 

from Berger Ditch after a rainfall event. Another site (W6) is 

located in Berger Ditch, downstream from where the wetlandtreated water discharges to Berger Ditch. Finally, site (M3) is 

in Maumee Bay of Lake Erie in the third swimming cove west 

of the mouth of Berger Ditch.

Rainfall and Streamflow Data

Rainfall data were obtained from a National Weather 

Service (NWS) station at Toledo Executive Airport (Station 

Identifier: Toledo Metcalf Field, WBAN: 04848) by accessing 

the historical data from the National Oceanic and Atmospheric 

Administration (NOAA, 2016). Daily rainfall amounts were 

tabulated, and the sum of the 2 days prior to the day of sampling was calculated for each sample. Samples collected when 

the sum of the previous 2 days of rainfall was greater than 

0.56 inches were classified as wet-weather samples, whereas 

samples collected when the previous 2 days of rainfall was 

0.56 inches or less were classified as dry-weather samples. 

This classification threshold was determined by examining 

the distribution of the previous 2-day rainfall data during the 

entire study period and calculating the 90th percentile.

Sampling Procedures

Samples were collected into sterile 1-liter polypropylene bottles using the hand-dip method as described in the 

USGS National Field Manual Section 7.1.2.A (USGS, 2014). 

WLCS sites were sampled by opening the concrete hatch and 

dipping the sample bottle into the pooled water contained 

therein. Samples were maintained on ice during transport to 

the University of Toledo Lake Erie Center laboratory, Oregon, 

Ohio, and during handling and transport to the Ohio Water 

Microbiology Laboratory (OWML) in Columbus, Ohio. Two 
Methods of Study 3

83°23' 83°22'30" 83°22'

41°41'

41°40'30"

0

0

Base map data from Google, 2016

State Plane Ohio, North, FIPS 3401

North American Datum of 1983

0.1 0.2 MILES

0.1 0.2 KILOMETERS

Maumee Bay (LAKE ERIE) Berger Ditch

#

M3

W6

W2 W4 W5

W1 04194085

M3

#

# ##

# W6

W2 W4 W5

W1 04194085

#

EXPLANATION

Water-quality site and 

 identification number

Surface-water site and 

 identification number

W5

04194085

Study Area

OHIO

W6

W2 W4 W5

04194085 W1

0

0

# # #

#

#

100 200 FEET

25 50 METERS

W6

W2 W4 W5

04194085 W1

Figure 1. Location of sample collection sites in Maumee Bay State Park, Oregon, Ohio, 2015–16.
4 E. coli and Microbial Tracking Marker Concentrations at Constructed Wetland in Maumee Bay State Park, OH., 2015–16

concurrent field replicate samples were collected during the 

sampling period, both from site W1. Most samples were collected by University of Toledo personnel and shipped to the 

OWML for processing within 24 hours. Samples collected outside the routine schedule were collected by USGS personnel.

Laboratory Analyses and Associated Laboratory 

Quality Control

Escherichia coli Analysis

For those samples collected by USGS personnel (collected on February 3, 2016) and all samples collected at 

Maumee Bay cove 3 (site M3), E. coli concentrations were 

determined by use of the Colilert Quanti-Tray/2000 method 

(IDEXX Laboratories, Inc.; Westbrook, Maine). Results for 

the water samples were recorded as the most probable number 

per 100 milliliters of sample (MPN/100 mL). The two concurrent replicate samples were processed by use of the Colilert 

method.

For those samples collected by University of Toledo personnel at sites W1, W2, W4, W5, and W6, analyses for E. coli 

concentrations were done using the modified mTEC membrane-filtration method (USEPA, 2009). The concentrations of 

E. coli in the samples were recorded as colony-forming units 

per 100 milliliters (CFU/100 mL).

Microbial Source Tracking Marker Analyses

DNA Extraction and qPCR Analyses

In the OWML, an aliquot of each water sample (up to 

100 milliliters [mL]) was filtered through a 0.4-micrometer, 47-millimeter polycarbonate filter (Whatman; Florham 

Park, N.J.). Filters were then folded aseptically and placed into 

2-mL screw-cap vials containing 0.3 grams of acid-washed 

glass beads (Sigma-Aldrich Corp.; St. Louis, Mo.). Negative 

controls (filter blanks) were filtered each day that samples 

were processed using sterile buffered water. Filtered samples 

were then stored at -70 degrees Celsius (°C) until subsequent 

analysis.

Samples underwent DNA extraction by means 

of the DNA-EZ extraction kit from GeneRite (North 

Brunswick, N.J.). The extraction was done according to the 

manufacturer’s instructions, except that no prefilter was used. 

Negative extraction controls (extraction blanks), consisting of a 2-mL vial containing only acid-washed glass beads, 

were processed with each batch of extractions. DNA extracts 

were stored at 4 °C until subsequent analysis by qPCR within 

5 days of extraction.

Sample extracts were analyzed by qPCR for four MST 

markers: a general Bacteroides marker (GenBac)(Siefring 

and others, 2008), a human-associated Bacteroides marker 

(HF183) (Bernhard and Field, 2000; Seurinck and others, 

2005), a waterfowl-associated Helicobacter marker (GFD) 

(Green and others, 2012), and a ruminant-associated Bacteroides marker (Rum2Bac) (Mieszkin and others, 2010). All 

qPCR analyses were performed using either an Applied Biosystems StepOne Plus or Model 7500 thermal cycler (Applied 

Biosystems; Foster City, Calif.). All samples were analyzed 

in duplicate. No-template controls (qPCR blanks), consisting 

of molecular-grade sterile water instead of DNA extract, were 

included on each qPCR plate in duplicate. For all samples, 

matrix inhibition was tested using matrix spikes, and results 

from diluted samples were used if inhibition was detected 

(Francy and others, 2017).

Standard Curves and Quantifying Microbial Source 

Tracking Markers

Standard curves were generated using plasmids containing the sequences for each of the targeted MST marker 

genes (Francy and Stelzer, 2012). Each qPCR run included a 

seven-point standard curve run in duplicate. Standard curve 

characteristics are listed in table 1. Amplification efficiency 

is calculated from the slope of the log-linear portion of the 

standard curve, specifically, PCR efficiency = 10-1/slope - 1 

Table 1. Standard curve characteristics and limits of detection and quantification for microbial source tracking markers.

[MST, microbial source tracking; R2, coefficient of determination; qPCR, quantitative polymerase chain reaction; GenBac, general Bacteroides marker; HF183, 

human-associated Bacteroides marker; GFD, waterfowl-associated Helicobacter marker; Rum2Bac, ruminant-associated Bacteroides marker]

MST marker

Number of 

standard 

curves run

Average 

amplification 

efficiency 

(percent)

Average R2 value 

Limit of detection Limit of 

quantification

(copies/qPCR 

reaction)

(copies/qPCR 

reaction)

GenBac 6 96 0.998 3 11

HF183 6 101 0.998 25 66

GFD 5 95 0.999 27 68

Rum2Bac 6 100 0.997 21 42
Escherichia coli and Microbial Source Tracking Marker Concentrations at Selected Sites Entering Maumee Bay, Lake Erie 5

(Bustin and others, 2009). Conversion of qPCR output to MST 

marker concentrations was done by interpolating from these 

standard curves.

To aid in the interpretation of qPCR results, limit of blank 

(LoB), limit of detection (LoD), and limit of quantification 

(LoQ) were determined for each assay to describe the lowest 

concentration of each MST marker that can be differentiated 

from blank sample results and can be reliably detected and 

quantified (Francy and others, 2017). The LoB is the lowest 

concentration that can be reported with 95-percent confidence 

to be greater than the concentration of the blanks; it was determined for each qPCR run on the basis of results from negative 

filtration controls, negative extraction controls, and no-template controls. The LoB was not used to report results unless it 

was greater than the LoD, in which case the LoB replaced the 

LoD. The LoD is the lowest concentration of a marker that can 

be detected with 95-percent confidence that it is a true detection and distinguishable from the blank sample results; LoD 

was determined by analyzing at least 10 replicates of each of 

several dilutions of a positive control. The LoQ is the lowest 

concentration of each MST marker that can be accurately quantified and is calculated from the standard deviation of the LoD 

replicates. If a sample result was less than the LoQ but greater 

than the LoD, the result was qualified as an estimate. If the 

MST marker was not detected in a sample or if the concentration was less than the LoD, then results were reported as less 

than the sample reporting limit (< SRL). The SRL is specific 

to each sample and is calculated using the LoD, taking into 

account the dilution analyzed and the initial sample volume 

filtered. The LoD and LoQ for each MST assay are listed in 

table 1.

Quality Control Measures of Variability 

and Bias

Two field concurrent replicates were collected and 

analyzed during this study, both from site W1 (table 2, fig. 1). 

For E. coli concentrations, the absolute value log difference 

(AVLD) for each replicate pair was 0 MPN/100 mL. For the 

GenBac and HF183 MST markers, the AVLDs ranged from 

Table 2. Quality-control concurrent replicate data for Escherichia coli and microbial source tracking markers, Maumee Bay State 

Park, Oregon, Ohio, 2014–16.

[AVLD is absolute value log10 difference between replicates A and B; Escherichia coli (E. coli) are reported in most probable number per 100 milliliters; microbial source tracking markers are reported in copies per 100 milliliters; GenBac, general Bacteroides marker; HF183, human-associated Bacteroides marker]

Date

E. coli GenBac HF183

A B AVLD A B AVLD A B AVLD

9/11/2014 6,100 6,100 0.00 1.94E+09 1.39E+09 0.02 3.70E+04 2.89E+04 0.02

2/3/2016 330 330 0.00 5.80E+07 7.96E+07 0.02 1.85E+04 2.09E+04 0.01

0.01 to 0.02 copies/100 mL. For the GFD and Rum2Bac MST 

markers, results were less than the detection limit for both 

replicates.

Among the various negative control samples, 25 filter 

blanks, 20 extraction blanks, and the 23 qPCR blanks were 

analyzed. None of the results from these quality-control 

samples required removal of any data from the datasets. 

Additionally, none of the results from the negative control 

analyses required adjustment of established limits of detection 

or quantification.

Escherichia coli and Microbial Source 

Tracking Marker Concentrations at 

Selected Sites Entering Maumee Bay, 

Lake Erie

Based on the distribution analysis of the rainfall data, 

samples were classified as occurring during dry or wet 

weather. Wet-weather conditions occurred during three of the 

sampling dates with a total of 15 samples. This equates to 

13 percent of the 23 sampling dates as well as 13 percent of 

the 116 total samples collected.

Selected statistical tests were performed to evaluate 

differences in median concentrations between sampling sites 

and to evaluate the correlation between the GenBac marker 

and E. coli concentrations. An alpha level of 0.05 was used to 

assess statistical significance for all tests.

GenBac MST marker and E. coli concentrations, grouped 

into dry (boxplots) and wet weather (closed circles) sampling 

events, are shown in figure 2. Although there were far fewer 

wet-weather than dry-weather samples collected, some comparisons can be made. GenBac marker and E. coli concentrations during wet weather were in the same range as concentrations during dry weather with two notable exceptions: (1) 

GenBac concentrations at site W4 during wet weather were 

lower than concentrations during dry weather and (2) E. coli

concentrations in samples collected at site W1 and site W6 

during wet weather were higher than those in most or all 

samples collected during dry weather. Median GenBac and 
6 E. coli and Microbial Tracking Marker Concentrations at Constructed Wetland in Maumee Bay State Park, OH., 2015–16

100

101

102

103

104

104

105

106

107

108

109

GenBac copies per 100 milliliters Escherichia coli per 100 milliliters

(21,3) (19,3) (9,2) (12,1) (20,3) (19,3)

(15,1) (14,2) (6,2) (9,0) (14,1) (16,3)

W1 W2 W4 W5 W6 M3

EXPLANATION

Number of samples

Outliers1

Upper whisker2

75th percentile

25th percentile

Lower whisker2

Median of detections

1

Outliers are defined as values 

outside 1.5 times the interquartile 

range beyond the ends of the box

2

The whiskers are the largest and

smallest values within 1.5 times 

the interquartile range beyond 

the 75th and 25th percentiles, 

respectively 

(ndry, nwet)

Figure 2. Concentrations of the general marker GenBac and Escherichia coli during dry- and wet-weather sampling conditions 

Maumee Bay State Park, Oregon, Ohio, 2015–16. (Wet-weather samples are represented by closed circles. Boxplots are not drawn 

for wet-weather sample concentrations as, at most, there were only three such occurrences at a given site. Escherichia coli

concentrations include both most probable number/100 milliliters (Colilert analysis) and colony-forming units/100 milliliters (mod mTEC 

analysis). Sites in the plot with gray shaded vertical panels are in the constructed wetland.)
Escherichia coli and Microbial Source Tracking Marker Concentrations at Selected Sites Entering Maumee Bay, Lake Erie 7

E. coli concentrations, regardless of precipitation, were highest 

at sites W1 and W6, both in Berger Ditch. HF183, GFD, and 

Rum2Bac MST markers were not detected frequently enough 

at greater than the detection limit to be presented in boxplots 

such as those in figure 2.

Results of a Wilcoxon rank-sum test (Helsel and Hirsch, 

2002) indicate that median E. coli concentrations at sites W1 

and W6 (sites upstream and downstream from the wetland in 

Berger Ditch) were not significantly different (p = 0.43). However, results of this same test indicate that median GenBac 

marker concentrations at sites W1 and W6 were significantly 

different (p = 0.01). The median GenBac concentrations at 

sites W1 and W6 were 1.7 x 107 and 7.8 x 106 copies per 

100 mL, respectively.

E. coli and MST marker concentration results are presented in appendix 1. Wet-weather sampling dates (7/20/2015, 

8/3/2015, and 8/31/2015) are shaded and detections of the 

MST markers HF183 and GFD are bold. The general marker 

(GenBac) was detected in all samples and ranged in concentration from 3.1 x 104

 to 1.2 x 108 copies/100 mL. Results of 

Spearman’s rank correlation analysis indicate that log concentrations of the GenBac marker correlate with log concentrations of E. coli (rho = 0.51, p < 0.0001). Of the 21 detections 

of the HF183 human-associated marker, 14 occurred on just 

four sampling dates. HF183 was detected at three or more sites 

on each of those four dates, and only one of the four dates was 

classified as wet weather (appendix 1). The Rum2Bac marker 

was not detected at greater than the sample reporting limits in 

any sample (data not shown).

Summary statistics with combined wet and dry weather 

results for the HF183 and GFD MST markers are presented 

in table 3. Although the percent detection of HF183 was 

lower for Berger Ditch site W6 (22 percent) than for W1 

(39 percent), the median concentration of those detections 

was about the same for W1 and W6 (2.7 x 103 and 2.8 x 103

copies/100 mL). The GFD waterfowl maker was detected in 

13 samples, most frequently at site W5. This was unexpected 

because this site was a WLCS site and thus closed off from 

direct contact with waterfowl feces, but the presence of the 

GFD marker could have been the result of waterfowl using the 

wetland holding pond. Two samples contained GFD concentrations nearly 1 log and 3 logs greater than all other detections (6.0 x 104

 copies/100 mL at site W1 on September 23, 

2015, and 1.2 x 106 copies/100 mL at site M3 on August 31, 

2015).

In this study, samples were collected and analyzed for 

E. coli and MST marker concentrations at six sites in and near 

a subsurface treatment wetland constructed in Maumee Bay 

State Park. These data are available for review or download 

from the USGS National Water Information System Web 

Interface and can be found using the hyperlinks associated 

with the site numbers in table 3 (USGS, 2018). Given the low 

frequency of detection of MST markers such as HF183 and 

GFD, a larger dataset with multiple years of sampling under 

varied hydrologic conditions would likely help to characterize fecal sources while also providing more information 

with which to evaluate the efficacy of restoration efforts. 

Additionally, given the estimated 2-day retention time of the 

wetland, high-frequency synoptic sampling during dry- and 

wet-weather conditions could improve the understanding of 

the wetland’s effect on the reduction of fecal microorganism 

contributions to Lake Erie.

Table 3. Summary statistics for detections of host-associated microbial source tracking markers in samples collected at Maumee Bay 

State Park, Oregon, Ohio, 2015–16.

[Microbial source tracking markers are reported in copies per 100 milliliters; ND, not determined because there were not enough detected concentrations; 

median concentrations were reported only when there were greater than two detections; HF183, human-associated Bacteroides marker; GFD, waterfowlassociated Helicobacter marker]

Site

Number 

of 

samples

HF183 Marker GFD Marker

Percent 

detection

Range of marker 

concentration

Mean 

concentration

Median 

concentration

Percent 

detection

Range of marker 

concentration

Mean 

concentration

Median 

concentration

W1 23 39 8.40E+02 - 2.50E+04 7.50E+03 2.70E+03 13 1.20E+03 - 6.00E+04 2.30E+04 7.10E+03

W2 22 9 3.10E+03 - 1.60E+04 9.30E+03 ND 0 ND ND ND

W4 11 9 2.10E+03 ND ND 18 6.90E+02 - 2.30E+03 1.50E+03 ND

W5 13 15 9.80E+02 - 3.40E+03 2.20E+03 ND 46 6.20E+02 - 3.50E+03 1.80E+03 1.60E+03

W6 23 22 1.30E+03 - 1.70E+04 5.30E+03 2.80E+03 0 ND ND ND

M3 22 9 4.50E+03 - 9.10E+03 6.80E+03 ND 9 1.70E+03 - 1.20E+06 6.10E+05 ND
8 E. coli and Microbial Tracking Marker Concentrations at Constructed Wetland in Maumee Bay State Park, OH., 2015–16

Summary

A study was conducted by the U.S. Geological Survey 

in cooperation with the University of Toledo to evaluate the 

effects of a constructed wetland on microbial water-quality 

constituents. Elevated Escherichia coli (E. coli) concentrations at the Maumee Bay State Park (MBSP) Lake Erie beach 

have resulted in frequent recreational water-quality advisories. 

Sources of these elevated E. coli concentrations at the beach 

are not well understood, but previous studies have indicated 

that Berger Ditch has an important effect on water quality at 

and near the beach. Putative sources of fecal contamination 

that may affect the study area include runoff and (or) drainage 

from fields that have been treated with biosolids applied as 

fertilizer, failing septic systems, and waterfowl.

As part of an effort to improve water quality at the MBSP 

Lake Erie beach, the University of Toledo designed and 

implemented a novel wetland along Berger Ditch. Sampling 

was done in 2015 and early 2016 to determine concentrations of E. coli and selected microbial source tracking (MST) 

markers in and around the wetland. The specific MST markers analyzed were a general Bacteroides marker (GenBac), a 

human-associated Bacteroides marker (HF183), a waterfowlassociated Helicobacter marker (GFD), and a ruminant-associated Bacteroides marker (Rum2Bac). Samples were collected 

from 6 sites: 2 were in Berger Ditch (W1, upstream from the 

wetland and W6, downstream from the wetland), 3 were in 

subsurface water-level control structures within the wetland 

(W2, before the first wetland cell; W4, between wetland cells 

2 and 3; and W5, between wetland cell 3 and re-entry to 

Berger Ditch), and 1 was in the swimming area at the Lake 

Erie beach at MBSP (M3).

Median GenBac and E. coli concentrations were highest in samples from sites in Berger Ditch (W1 and W6), and 

lower concentrations were present in samples from wetland 

sites (W2, W4, and W5). The effect of the wetland (if any) on 

removal of E. coli and GenBac in Berger Ditch is uncertain. 

The results of a Wilcoxon rank-sum test indicate that median 

E. coli concentrations at sites W1 and W6 (sites upstream 

and downstream from the wetland in Berger Ditch) were not 

significantly different (p = 0.43). However, results of this 

same test indicate that median GenBac marker concentrations 

at sites W1 and W6 were significantly different (p = 0.01). 

The median GenBac concentrations at sites W1 and W6 

were 1.7 x 107 and 7.8 x 106 copies per 100 milliliters (mL), 

respectively.

The source-associated MST markers were not detected 

frequently enough to draw conclusions regarding the wetland’s effect on their fate and transport in Berger Ditch. In the 

116 samples analyzed, HF183 was detected only 21 times, and 

GFD was detected only 13 times. Rum2Bac was not detected 

in any of the samples analyzed. Although the percent detection of HF183 was somewhat lower at site W6 (22%) than at 

site W1 (39%), the median concentration of those detections 

was about the same at both sites (2.7 x 103 copies/100 mL 

at site W1 and 2.8 x 103 copies/100 mL at site W6). GFD 

was detected most frequently at site W5. This was unexpected 

because this was a subsurface site, but the presence of GFD 

could have resulted from waterfowl using the wetland holding 

pond.

Given the low frequency of detection for MST markers and 

the complexity of the wetland at Berger Ditch, a larger dataset 

with multiple years of sampling data could provide more information to evaluate the efficacy of the water-quality restoration 

efforts in Maumee Bay State Park. High-frequency synoptic 

sampling in and around the wetland during various hydrologic 

conditions also could provide more resolution for the effect of 

the wetland on microbiological constituents of concern.

References Cited

Bernhard, A.E., and Field, K.G., 2000, A PCR assay to discriminate human and ruminant feces on the basis of host differences in Bacteroides-Prevotella genes encoding 16S rRNA: 

Applied and Environmental Microbiology, v. 66, no. 10, 

p. 4571–4574.

Boehm, A.B., Ashbolt, N.J., Colford, J.M., Dunbar, L.E., Fleming, L.E., Gold, M.A., Hansel, J.A., Hunter, P.R., Ichida, 

A.M., McGee, C.D., Soller, J.A., and Weisberg, S.B., 2009, 

A sea change ahead for recreational water quality criteria: 

Journal of Water Health, v. 7, no. 1, p. 9–20.

Boehm, A.B., Van De Werfhorst, L.C., Griffith, J.F., Holden, 

P.A., Jay, J.A., Shanks, O.C., Wang, D., and Weisberg, S.B., 

2013, Performance of forty-one microbial source tracking methods: A twenty-seven lab evaluation study: Water 

Resources, v. 47, p. 6812–6828.

Bustin, S.A., Benes, V., Garson, J.A., Hellemans, J., Huggett, 

J., Kubista, M., Mueller, R., Nolan, T., Pfaffl, M.W., Shipley, 

G.L., Vandesompele, J., and Wittwer, C.T., 2009, Clinical 

Chemistry, v. 55, no. 4, p. 611–622.

Colford, J.M., Wade, T.J., Schiff, K.C., Wright, C.C., Griffith, 

J.F., Sandhu, S.K., Burns, S., Sobsey, M., Lovelace, G., and 

Weisberg, S.B., 2007, Water quality indicators and the risk of 

illness at beaches with nonpoint sources of fecal contamination: Epidemiology, v. 18, no. 1, p. 27–35.

Francy, D.S., Struffolino, P., Brady, A.M.G., and Dwyer, D.F., 

2005, A spatial, multivariable approach for identifying proximate sources of Escherichia coli to Maumee Bay, Lake Erie, 

Ohio: U.S. Geological Survey Open-File Report 2005–1386, 

20 p.

Francy, D.S., Brady, A.M.G., Carvin, R.B., Corsi, S.R., Fuller, 

L.M., Harrison, J.H., Hayhurst, B.A., Lant, J., Nevers, M.B., 

Terrio, P.J., and Zimmerman, T.M., 2013, Developing and 

implementing predictive models for estimating recreational 

water quality at Great Lakes beaches: U.S. Geological Survey 

Scientific Investigations Report 2013–5166, 68 p.
References Cited 9

Francy, D.S., Bushon, R.N., Brady, A.M.G., Kephart, C.M., 

Stelzer, E.A., and Ecker, C.D., 2017, Quality Assurance/

Quality Control Manual: Ohio Water Microbiology Laboratory, accessed April 3, 2018, at http://oh.water.usgs.gov/

micro_qaqc.htm.

Francy, D.S., and Stelzer, E.A., 2012, Microbial source tracking markers at three inland recreational lakes in Ohio, 2011: 

U.S. Geological Survey Open-File Report 2012–1222, 8 p.

Green, H.C., Dick, L.K., Gilpin, B., Samadpour, M., and 

Field, K.G., 2012, Genetic markers for rapid PCR-based 

identification of gull, Canada goose, duck, and chicken fecal 

contamination in water: Applied and Environmental Microbiology, v. 78, no. 2, p. 503–510.

Helsel, D.R., and Hirsch, R.M., 2002, Statistical Methods in 

Water Resources. U.S. Geological Survey Techniques of 

Water-Resources Investigations, Book 4, chapter A3, 522 p.

Mieszkin, S., Yala, J.F., Joubrel, R., and Gourmelon, M., 2010, 

Phylogenetic analysis of Bacteroidales 16S rRNA gene 

sequences from human and animal effluents and assessment 

of ruminant faecal pollution by real-time PCR: Journal of 

Applied Microbiology, v. 108, p. 974–984.

National Oceanic and Atmospheric Administration (NOAA), 

2016, National Centers for Environmental InformationLocal Climatological Data: Asheville, N.C., accessed May 

16, 2018 at https://www.ncdc.noaa.gov/cdo-web/datatools/

lcd.

Seurinck, S., Defoirdt, T., Verstraete, W., and Siciliano, S.D., 

2005, Detection and quantification of the human-specific 

HF183 Bacteroides 16S rRNA genetic marker with realtime PCR for assessment of human faecal pollution in freshwater: Environmental Microbiology, v. 7, no. 2, p. 249–259.

Siefring, S., Varma, M., Atikovic, E., Wymer, L., and Haugland R., 2008, Improved real-time PCR assays for the 

detection of fecal indicator bacteria in surface waters with 

different instrument and reagent systems: Journal of Water 

and Health, v. 6, no. 2, p. 225–237.

Soller, J.A., Schoen, M.E., Bartrand, T., Ravenscroft, J.E., 

and Ashbolt, N.J., 2010, Estimated human health risks 

from exposure to recreational waters impacted by human 

and nonhuman sources of faecal contamination: Water 

Resources, v. 44, no. 16, p. 4674–4691.

U.S. Environmental Protection Agency (USEPA), 2009, 

Method 1603: Escherichia coli (E. coli) in water by membrane filtration using modified membrane-thermotolerant 

Escherichia coli agar (modified mTEC), Washington, D.C., 

EPA-821-R-09-007, 24 p.

U.S. Environmental Protection Agency (USEPA), 2012, Recreational water quality criteria, Office of Water 820-F-12-

058, accessed April 3, 2018, at http://water.epa.gov/scitech/

swguidance/standards/criteria/health/recreation/upload/

RWQC2012.pdf.

U.S. Geological Survey (USGS), 2014, National field manual 

for the collection of water-quality data: U.S. Geological 

Survey Techniques of Water-Resources Investigations, 

book 9, chap. A7, accessed May 16, 2018, at http://water.

usgs.gov/owq/FieldManual/.

U.S. Geological Survey (USGS), 2018, National Water Information System—Web Interface: U.S. Geological Survey 

web page, accessed September 10, 2018, at https://dx.doi.

org/10.5066/F7P55KJN.

World Health Organization (WHO), 1999, Health-based 

monitoring of recreational waters: The feasibility of a new 

approach (the ‘‘Annapolis Protocol’’): Geneva, World 

Health Organization.

World Health Organization (WHO), 2003, Guidelines for safe 

recreational water environments, Volume 1: Coastal and 

Freshwaters: Geneva, World Health Organization.
10 E. coli and Microbial Tracking Marker Concentrations at Constructed Wetland in Maumee Bay State Park, OH., 2015–16

Appendix 1.

Concentrations of Escherichia coli and microbial source tracking markers at Berger Ditch, wetland, and Maumee 

Bay sites, Oregon, Ohio, 2015–16.
Appendix 1 11

Appendix 1. Concentrations of Escherichia coli and microbial source tracking markers at Berger Ditch, wetland, and Maumee Bay 

sites, Oregon, Ohio, 2015–16.

[MST, microbial source tracking; E. coli, Escherichia coli; MPN, most probable number; CFU, colony forming units; mL, milliliters; GenBac, general Bacteroides marker; --, analysis not done; <, less than; E, value was estimated; b, extrapolated below the limit of quantification; ~, duplicate quantitative polymerase 

chain reaction results did not agree; wet-weather sample sets are shaded; detections of human-associated Bacteroides marker (HF183) or waterfowl-associated 

Helicobacter marker (GFD) are bold]

Sample 

date Site E. coli(MPN or CFU/100 mL)

MST marker (copies/100 mL)

GenBac

(general)

HF183

(human)

GFD

(waterfowl)

7/8/2015

W1 -- 2.00E+07 2.70E+03 <9.00E+02

W5 -- 4.50E+07 E~ 3.40E+03 <6.30E+02

W6 -- 4.60E+07 2.80E+03 <6.40E+02

M3 610 5.90E+07 <1.00E+03 <9.90E+01

7/20/2015

W1 -- 2.20E+07 2.50E+04 <1.70E+03

W2 320 3.20E+06 <5.90E+02 <5.60E+02

W4 20 3.10E+04 Eb~ 2.10E+03 <1.10E+03

W6 -- 1.10E+07 3.60E+03 <1.50E+03

M3 150 3.80E+06 <7.10E+02 <5.10E+02

7/22/2015

W1 840 1.50E+07 Eb 1.90E+03 Eb~ 1.20E+03

W2 1,000 3.90E+06 3.10E+03 <1.00E+02

W5 250 6.20E+06 <1.00E+03 <3.40E+02

W6 880 7.80E+06 Eb~ 1.80E+03 <1.10E+03

M3 290 3.30E+07 <1.00E+03 <8.30E+02

7/27/2015

W1 830 9.60E+06 <1.00E+03 <4.30E+02

W2 1,300 1.50E+06 <1.00E+03 <1.10E+03

W4 170 8.50E+05 <5.00E+02 <5.40E+02

W6 1,300 4.50E+06 Eb~ 1.30E+03 <1.10E+03

M3 250 9.50E+05 <1.00E+03 <1.10E+03

7/29/2015

W1 830 1.40E+07 <1.00E+03 <1.10E+03

W2 270 4.60E+05 <1.00E+03 <1.10E+03

W5 39 9.90E+05 <5.00E+02 Eb~ 6.20E+02

W6 480 1.20E+07 <1.00E+03 <3.70E+02

M3 47 1.00E+06 <1.00E+03 <6.40E+02

8/3/2015

W1 -- 1.40E+07 2.80E+03 <1.10E+03

W2 -- 5.60E+06 <6.70E+02 <2.50E+02

W5 -- 2.40E+06 <6.70E+02 Eb 9.30E+02

W6 -- 2.30E+07 <6.70E+02 <6.10E+02

M3 230 1.90E+06 <1.00E+03 <1.10E+03

8/5/2015

W1 210 1.60E+07 1.30E+04 <8.30E+02

W2 76 7.80E+05 <7.10E+02 <7.70E+02

W5 11 1.50E+06 <7.10E+02 <7.70E+02

W6 220 7.40E+06 <1.40E+03 <5.10E+02

M3 120 5.70E+06 <1.40E+03 <1.50E+03

8/10/2015

W1 2,700 4.50E+07 Eb~ 1.40E+03 <2.00E+02

W2 230 3.20E+06 <1.00E+03 <1.10E+03

W5 8,000 1.60E+05 <5.00E+02 1.30E+03

W6 840 4.10E+07 <1.00E+03 <4.60E+02

M3 240 1.30E+06 9.10E+03 <1.10E+03
12 E. coli and Microbial Tracking Marker Concentrations at Constructed Wetland in Maumee Bay State Park, OH., 2015–16

Appendix 1. Concentrations of Escherichia coli and microbial source tracking markers at Berger Ditch, wetland, and Maumee Bay 

sites, Oregon, Ohio, 2015–16.—Continued

[MST, microbial source tracking; E. coli, Escherichia coli; MPN, most probable number; CFU, colony forming units; mL, milliliters; GenBac, general Bacteroides marker; --, analysis not done; <, less than; E, value was estimated; b, extrapolated below the limit of quantification; ~, duplicate quantitative polymerase 

chain reaction results did not agree; wet-weather sample sets are shaded; detections of human-associated Bacteroides marker (HF183) or waterfowl-associated 

Helicobacter marker (GFD) are bold]

Sample 

date Site E. coli(MPN or CFU/100 mL)

MST marker (copies/100 mL)

GenBac

(general)

HF183

(human)

GFD

(waterfowl)

8/12/2015

W1 90 5.90E+06 <5.00E+02 <1.50E+01

W2 48 1.20E+06 <7.10E+02 <1.20E+02

W5 8,000 3.20E+05 <5.00E+02 <5.40E+02

W6 160 2.00E+06 <8.30E+02 <9.00E+02

M3 96 1.90E+06 <1.40E+03 <1.50E+03

8/17/2015

W1 -- 5.50E+06 <8.30E+02 <9.00E+02

W2 -- 1.40E+06 <7.10E+02 <1.80E+02

W4 -- 5.10E+06 <7.10E+02 2.30E+03

W6 -- 2.80E+06 <1.00E+03 <3.40E+02

M3 46 7.10E+05 <1.00E+03 <1.10E+03

8/19/2015

W1 160 1.20E+07 Eb~ 1.20E+03 <2.60E+02

W2 100 2.20E+06 <1.00E+03 <2.20E+02

W4 6 2.20E+06 <8.30E+02 <9.00E+02

W6 220 8.10E+06 <7.10E+02 <5.60E+01

M3 88 3.90E+06 <1.70E+03 <1.80E+03

8/24/2015

W1 130 6.40E+06 <8.30E+02 7.10E+03

W2 24 5.50E+05 <6.70E+02 <7.20E+02

W4 8 7.10E+05 <6.70E+02 <7.20E+02

W6 120 3.50E+06 <8.30E+02 <5.10E+02

M3 80 3.40E+05 <1.40E+03 <1.50E+03

8/26/2015

W1 70 3.20E+06 <7.70E+02 <1.80E+01

W2 24 1.40E+06 <8.30E+02 <9.00E+02

W4 1 3.40E+05 <8.30E+02 <9.00E+02

W6 150 2.20E+06 <1.00E+03 <5.40E+02

M3 6 1.40E+06 <2.50E+03 <2.70E+03

8/31/2015

W1 1,300 2.50E+07 Eb~ 8.40E+02 <9.00E+02

W2 65 1.20E+06 <7.10E+02 <7.70E+02

W4 1 5.00E+05 <6.20E+02 Eb~ 6.90E+02

W6 3,400 9.60E+06 <8.30E+02 <9.00E+02

M3 82 9.70E+05 <1.40E+03 1.20E+06

9/2/2015

W1 120 2.30E+07 <7.70E+02 <1.50E+01

W2 30 4.10E+05 <1.00E+03 <7.40E+02

W4 3 1.70E+06 <6.70E+02 <4.60E+02

W6 380 2.60E+06 <7.70E+02 <8.30E+02

M3 93 1.90E+06 <1.40E+03 <1.50E+03

9/9/2015

W1 -- 1.70E+07 <1.00E+03 <4.30E+01

W2 -- 1.20E+06 <1.00E+03 <1.10E+03

W4 -- 7.30E+05 <5.00E+02 <5.40E+02

W6 -- 4.60E+06 <1.00E+03 <6.10E+02

M3 -- 6.50E+06 <1.00E+03 <1.10E+03
Appendix 1 13

Appendix 1. Concentrations of Escherichia coli and microbial source tracking markers at Berger Ditch, wetland, and Maumee Bay 

sites, Oregon, Ohio, 2015–16.—Continued

[MST, microbial source tracking; E. coli, Escherichia coli; MPN, most probable number; CFU, colony forming units; mL, milliliters; GenBac, general Bacteroides marker; --, analysis not done; <, less than; E, value was estimated; b, extrapolated below the limit of quantification; ~, duplicate quantitative polymerase 

chain reaction results did not agree; wet-weather sample sets are shaded; detections of human-associated Bacteroides marker (HF183) or waterfowl-associated 

Helicobacter marker (GFD) are bold]

Sample 

date Site E. coli(MPN or CFU/100 mL)

MST marker (copies/100 mL)

GenBac

(general)

HF183

(human)

GFD

(waterfowl)

9/14/2015

W1 790 2.40E+07 <1.40E+03 <1.50E+03

W2 590 5.30E+06 <1.40E+03 <7.80E+02

W5 69 7.60E+05 <6.70E+02 E~ 3.50E+03

W6 700 2.30E+07 <1.40E+03 <1.30E+02

M3 90 1.40E+06 <1.40E+03 <1.50E+03

9/16/2015

W1 -- 1.40E+07 <1.00E+03 <1.10E+03

W2 -- 1.30E+06 <1.70E+03 <9.10E+02

W5 -- 5.60E+05 <7.70E+02 2.00E+03

W6 -- 8.80E+06 <1.00E+03 <1.10E+03

M3 -- 6.10E+05 <1.40E+03 <1.50E+03

9/21/2015

W1 -- 1.20E+08 <1.40E+03 <1.50E+03

W2 -- 7.90E+05 <1.00E+03 <5.50E+02

W5 -- 1.30E+05 <1.40E+03 <8.10E+02

W6 -- 1.90E+07 <1.40E+03 <8.00E+02

M3 -- 6.40E+07 <1.40E+03 <1.50E+03

9/23/2015

W1 -- 1.80E+07 <6.70E+02 6.00E+04

W2 -- 4.50E+05 <1.00E+03 <5.60E+02

W4 -- 2.00E+06 <6.70E+02 <7.20E+02

W6 -- 7.00E+06 <1.00E+03 <6.00E+02

9/28/2015

W1 170 3.30E+07 <6.70E+02 <7.20E+02

W2 57 1.10E+07 <8.30E+02 <9.00E+02

W5 6 1.00E+06 <5.00E+02 <5.40E+02

W6 170 4.00E+06 <6.70E+02 <7.20E+02

M3 57 1.30E+06 <1.40E+03 <1.50E+03

9/30/2015

W1 180 2.30E+07 <5.00E+02 <5.40E+02

W2 38 2.80E+05 <5.00E+02 <5.40E+02

W5 1 1.70E+06 <5.00E+02 <5.40E+02

W6 350 4.60E+06 <7.10E+02 <7.70E+02

M3 640 8.10E+06 <2.00E+03 <2.20E+03

2/3/2016

W1 330 5.80E+07 1.80E+04 <3.70E+02

W2 60 2.50E+07 1.60E+04 <7.20E+02

W4 5 2.60E+06 <5.00E+02 <5.40E+02

W5 3 5.50E+06 Eb 9.80E+02 E~ 2.70E+03

W6 370 4.40E+07 1.70E+04 <4.30E+02

M3 21 5.90E+06 E~ 4.50E+03 Eb~ 1.70E+03
For additional information, contact:

Director, Ohio-Kentucky-Indiana Water Science Center

U.S. Geological Survey

6460 Busch Blvd, Suite 100

Columbus, OH 43229-1737

Or visit our website at:

https://www.usgs.gov/centers/oki-water

Publishing support provided by the West Trenton 

Publishing Service Center
Kephart and others—E. coli and Microbial Tracking Marker Concentrations at Constructed Wetland in Maumee Bay State Park, OH., 2015–16—Scientific Investigations Report 2018–5127

ISSN 2328-0328 (online)

https://doi.org/10.3133/sir20185127