Prepared in cooperation with the 

Milwaukee Metropolitan Sewerage District

Organic Waste Compounds in Streams: Occurrence and 

Aquatic Toxicity in Different Stream Compartments, Flow 

Regimes, and Land Uses in Southeast Wisconsin, 2006–9

Scientific Investigations Report 2013–5104

U.S. Department of the Interior

U.S. Geological Survey
Cover: All photos provided by Milwaukee Metropolitan Sewerage District.

Upper left: Fishing the falls on the Milwaukee River at Estabrook Park, Milwaukee, Wis.

 Lower left: Kayakers explore the Milwaukee Estuary, Milwaukee, Wis.

 Upper right: Children play on the banks of the Menomonee River at Lime Kiln Park, Menomonee Falls, Wis.

 Lower right: Diners enjoy the sunshine at an outdoor café along the Riverwalk, downtown Milwaukee, Wis.
Organic Waste Compounds in Streams: 

Occurrence and Aquatic Toxicity in 

Different Stream Compartments, Flow 

Regimes, and Land Uses in Southeast 

Wisconsin, 2006–9

By Austin K. Baldwin, Steven R. Corsi, Kevin D. Richards, Steven W. Geis, and 

Christopher Magruder 

Prepared in cooperation with the

Milwaukee Metropolitan Sewerage District

Scientific Investigations Report 2013–5104

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

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reproduce any copyrighted materials contained within this report.

Suggested citation:

Baldwin, A.K., Corsi, S.R., Richards, K.D., Geis, S.W., and Magruder, C., 2013, Organic waste compounds in streams: 

occurrence and aquatic toxicity in different stream compartments, flow regimes, and land uses in southeast 

Wisconsin, 2006–9: U.S. Geological Survey Scientific Investigations Report 2013–5104, 46 p.
iii

Contents

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

Introduction.....................................................................................................................................................2

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

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

Water and Sediment Sampling: Design and Collection .........................................................................5

Sampling Design ...................................................................................................................................5

Sample-Collection Methods ...............................................................................................................5

Analytical Methods........................................................................................................................................6

Organic Waste Compounds ................................................................................................................6

Bioassays for Toxicity Testing in Sediment .....................................................................................6

Bioassays for Toxicity Testing in Water...........................................................................................7

Quality Assurance/Quality Control .............................................................................................................7

Data Analysis..................................................................................................................................................7

Organic Waste Compounds ................................................................................................................7

Toxicity in Stream Compartments .....................................................................................................8

Occurrence of Organic Waste Compounds .............................................................................................9

Detection Frequencies of Classes of OWCs ....................................................................................9

Detection Frequencies of Individual OWCs ...................................................................................12

Concentrations of OWCs ...................................................................................................................12

Domestic Wastewater Indicators....................................................................................................13

OWCs and Sampling Sites.................................................................................................................15

Adverse Impacts on Aquatic Life..............................................................................................................19

Endocrine-Disrupting Compounds...................................................................................................19

OWCs and Toxicity Benchmarks......................................................................................................19

Toxicity Bioassays .............................................................................................................................20

Summary and Conclusions.........................................................................................................................26

Acknowledgments.......................................................................................................................................26

References Cited..........................................................................................................................................27

Appendix 1. Summary of Test Conditions for Conducting Sediment-Toxicity Tests ...................46
iv

Figures

1. Map showing location of sampling sites, drainage basins, and land-use areas 

used in the study...........................................................................................................................4

2. Graphs showing percent of compounds detected per sample, organized by 

site and sample type ..................................................................................................................10

3. Graphs showing frequency of detection of organic waste compounds, by 

class, for each sample type ......................................................................................................11

4. Graph showing total detected concentrations of polycyclic aromatic 

hydrocarbons (PAHs) in stormflow and base-flow samples...............................................13

5. Graphs showing class-detection frequencies and maximum class concentrations for each site. A, Stormflow, base-flow, and pore-water samples. 

B, Sediment samples..................................................................................................................14

6. Graphs showing total detected class concentrations for each sample type ..................16

7. Graphs showing total detected concentration per sample of 20 domestic 

wastewater-indicator compounds commonly associated with sanitary sewer 

and septic sources .....................................................................................................................17

8. Map showing summary of the distribution of organic waste compounds in the 

Milwaukee Metropolitan Sewerage District (MMSD) planning area, Wisconsin ..........18

9. Graphs showing compounds with exceedances of toxicity benchmarks for one or 

more sample type. Bar heights indicate the percentage of samples exceeding the 

lowest benchmark listed in tables 4 and 5. Bar color indicates the maximum toxicity 

quotient (concentration/benchmark) observed for each compound. Compounds in 

red are known or suspected endocrine disruptors according to The Endocrine 

Disruption Exchange, Inc. ........................................................................................................21

10. Boxplots showing polycyclic aromatic hydrocarbons toxicity. A, Stormflow samples. 

B, Sediment samples. C, Base-flow samples. D, Pore-water samples. A sample with a 

potency factor greater than 1 is considered toxic, based on calculations developed 

by the U.S. Environmental Protection Agency (2010). Acute and chronic toxicity were 

calculated for each sample, using different computations (only chronic toxicity is 

shown for sediment samples). For the sediment-sample calculations, an expected 

range of organic content was used because the actual organic content was 

not known.....................................................................................................................................22

11. Graphs showing water-column bioassay results for 14 sites in the Milwaukee 

area, 2006–7. Error bars indicate the standard error of replicates for each result.........23

12. Graphs showing pore-water assay results for 14 sites in the Milwaukee area, 

2006–7. Error bars indicate the standard error of replicates for each result...................23

13. Graphs showing sediment assay results for 14 sites in the Milwaukee area, 

2006–7. Error bars indicate the standard error of replicates for each result...................24

14. Graph showing relation between Chironomus tentans weight and rank summations 

of concentrations of polycyclic aromatic hydrocarbons, solvents, and fire 

retardants in sediment samples...............................................................................................24
v

Tables

1. Site characteristics, land use, and types of samples collected, southeast 

Wisconsin, 2006–9 ........................................................................................................................3

2. Organic waste compounds sampled, their classes, and possible uses, southeast 

Wisconsin, 2006–9 ......................................................................................................................30

3. Detection statistics for organic waste compounds, by sample type, all sites 

combined, southeast Wisconsin, 2006–9..................................................................................9

4. Organic waste compounds sampled and summary of analytical results of water 

samples, southeast Wisconsin, 2006–9 ..................................................................................36

5. Organic waste compounds sampled and summary of analytical results of sediment 

samples, southeast Wisconsin, 2006–9 ..................................................................................42

6. Pearson correlation coefficients of Chironomus tentans weight to rank summations 

of concentrations of classes of organic waste compounds in sediment samples, 

southeast Wisconsin, 2006–9 ...................................................................................................25
vi

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.305 meter (m)

Area

square mile (mi2) 259 hectare (ha)

square mile (mi2) 2.59 square kilometer (km2)

Flow rate

cubic foot per second (ft3/s) 0.028 cubic meter per second (m3/s)

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.394 inch (in.)

Volume

liter (L) 33.82 ounce, fluid (fl. oz)

liter (L) 2.113 pint (pt)

liter (L) 1.057 quart (qt)

liter (L) 0.264 gallon (gal)

liter (L) 61.02 cubic inch (in3)

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

°F=(1.8×°C)+32

Horizontal coordinate information is referenced to the Wisconsin Transverse Mercator (WTM) 

Projection and the North American Datum of 1983 (NAD 83), with 1991 adjustment.

Concentrations of chemical constituents in water are given in micrograms per liter (μg/L).

Concentrations of chemical constituents in sediment are given in micrograms per kilogram 

(μg/kg).
vii

Acronyms and Abbreviations

AqT aquatic toxicity

CAS Chemical Abstracts Service

C. dubia 

C. tentans

DEET N,N-diethyl-meta-toluamide

DEHP Bis(2-ethylhexyl) phthalate

EDCs endocrine-disrupting compounds/chemicals

EPA U.S. Environmental Protection Agency

EWI equal-width increment

GC/MS gas chromatography/mass spectrometry

Ceriodaphnia dubia

Chironomus tentans

H. azteca Hyallela azteca

HCW Honey Creek at Wauwatosa

KRM Kinnickinnic River at S. 11th Street, at Milwaukee

LCM Lincoln Creek 47th Street at Milwaukee

LMM Little Menomonee River at Milwaukee

MDL minimum detection limit

MMF Menomonee River at Menomonee Falls

MMSD Milwaukee Metropolitan Sewerage District

MRC Milwaukee River near Cedarburg

MRJ Milwaukee River at the mouth at Jones Island

MRM Milwaukee River at Milwaukee

MRW Menomonee River at Wauwatosa

NP 4-Nonylphenol (sum of all isomers)

NWQL National Water Quality Laboratory

OH-03 Middle Harbor Milwaukee Outer Harbor Site

OH-14 Middle Outside Harbor Breakwater Lake Site

OSM Oak Creek at South Milwaukee

OWC organic waste compound

PAH polycyclic aromatic hydrocarbon

PCD Parnell Creek near Dundee

QA/QC quality assurance/quality control

RL reporting limit

RRF Root River near Franklin

RRG Root River at Grange Avenue, at Greenfield

SEWRPC Southeastern Wisconsin Regional Planning Commission

tPAH total concentration of polycyclic aromatic hydrocarbons

TQ toxicity quotients

UCW Underwood Creek at Wauwatosa

USGS U.S. Geological Survey

UV ultraviolet

WCG Willow Creek at Maple Road, near Germantown

WDNR Wisconsin Department of Natural Resources

YFC yeast/fish food/cereal leaves

Organic Waste Compounds in Streams: Occurrence and 

Aquatic Toxicity in Different Stream Compartments, Flow 

Regimes, and Land Uses in Southeast Wisconsin, 2006–9

By Austin K. Baldwin,1 Steven R. Corsi,1 Kevin D. Richards,2 Steven W. Geis,3 and Christopher Magruder4 

Abstract

An assessment of organic chemicals and aquatic toxicity in streams located near Milwaukee, Wisconsin, indicated 

high potential for adverse impacts on aquatic organisms that 

could be related to organic waste compounds (OWCs). OWCs 

used in agriculture, industry, and households make their way 

into surface waters through runoff, leaking septic-conveyance 

systems, regulated and unregulated discharges, and combined sewage overflows, among other sources. Many of these 

compounds are toxic at elevated concentrations and (or) 

known to have endocrine-disrupting potential, and often they 

occur as complex mixtures. There is still much to be learned 

about the chronic exposure effects of these compounds on 

aquatic populations. 

During 2006–9, the U.S. Geological Survey, in cooperation with the Milwaukee Metropolitan Sewerage District 

(MMSD), conducted a study to determine the occurrence 

and potential toxicity of OWCs in different stream compartments and flow regimes for streams in the Milwaukee area. 

Samples were collected at 17 sites and analyzed for a suite of 

69 OWCs. Three types of stream compartments were represented: water column, streambed pore water, and streambed 

sediment. Water-column samples were subdivided by flow 

regime into stormflow and base-flow samples.

One or more compounds were detected in all 196 samples 

collected, and 64 of the 69 compounds were detected at least 

once. Base-flow samples had the lowest detection rates, with 

a median of 12 compounds detected per sample. Median 

detection rates for stormflow, pore-water, and sediment 

samples1

 were more than double that of base-flow samples. 

Compounds with the highest detection rates include polycyclic 

aromatic hydrocarbons (PAHs), insecticides, herbicides, and 

dyes/pigments. 

1

 U.S. Geological Survey, Wisconsin Water Science Center

2

 U.S. Geological Survey, Iowa Water Science Center

3

 Wisconsin State Laboratory of Hygiene

4

 Milwaukee Metropolitan Sewerage District

Elevated occurrence and concentrations of some compounds were detected in samples from urban sites, as compared with more rural sites, especially during stormflow 

conditions. These include the PAHs and the domestic wastewater-indicator compounds, among others. Urban runoff and 

storm-related leaks of sanitary sewers and (or) septic systems 

may be important sources of these and other compounds to the 

streams. The Kinnickinnic River, a highly urbanized site, had 

the highest detection rates and concentrations of compounds of 

all the sampled sites. The Milwaukee River near Cedarburg—

one of the least urban sites—and the Outer Milwaukee Harbor 

site had the lowest detection rates and concentrations. 

Aquatic-toxicity benchmarks were exceeded for 12 of 

the 25 compounds with known benchmarks. The compounds 

with the greatest benchmark exceedances were the PAHs, both 

in terms of exceedance frequency (up to 93 percent for some 

compounds in sediment samples) and magnitude (concentrations up to 1,024 times greater than the benchmark value). 

Other compounds with toxicity-benchmark exceedances 

include Bis(2-ethylhexyl) phthalate (a plasticizer), 2-Methylnapthalene (a component of fuel and oil), phenol (an antimicrobial disinfectant with diverse uses), and 4-Nonylphenol (sum 

of all isomers; a detergent metabolite, among other uses). Analyzed as a mixture, the suite of PAH compounds were found to 

be potentially toxic for most non-base-flow samples. 

Bioassay tests were conducted on samples from 

14 streams: Ceriodaphnia dubia in base-flow samples, Ceriodaphnia dubia and Hyallela azteca in pore-water samples, and 

Hyallela azteca and Chironomus tentans in sediment samples. 

The greatest adverse effect was observed in tests with Chironomus tentans from sediment samples. The weight of Chironomus tentans after exposure to sediments decreased with 

increased OWC concentrations. This was most evident in the 

relation between PAH results and Chironomus tentans bioassay results for the majority of samples; however, solvents and 

flame retardants appeared to be important for one site each. 

These results for PAHs were consistent with assessment of 

PAH potency factors for sediment, indicating that PAHs were 

likely to have adverse effects on aquatic organisms in many of 

the streams studied. 
2 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Introduction

The occurrence and effects of organic waste compounds 

(OWCs) in streams has garnered increasing attention in recent 

years, both within the scientific community and in the popular 

press (Kolpin and others, 2002; Richardson and Ternes, 2005; 

Blue, 2012). OWCs are natural or synthetic chemicals derived 

from domestic, agricultural, and industrial wastewater sources. 

OWCs include fire retardants, fuel by-products, polycyclic 

aromatic hydrocarbons (PAHs), herbicides, antimicrobial 

disinfectants, and flavors and fragrances, among others. These 

compounds enter the environment through a number of pathways, including washing into streams from impervious surfaces and agricultural fields, industrial discharges into the air 

or water, leaching into the groundwater from unlined landfills, 

discharges from wastewater-treatment plants, combined sewer 

overflows, leaking septic systems, and leaking municipal 

sanitary and storm sewer systems (Kolpin and others, 2002; 

Gilliom and others, 2006; Phillips and others, 2012). 

Numerous recent studies have focused on the health 

effects of OWCs on aquatic communities (Thorpe and others, 

2001; U.S. Environmental Protection Agency, 2003; Barber 

and others, 2007; Vandenberg and others, 2012; Kemble and 

others, 2013). Although environmental concentrations tend 

to be low (generally, in the range of micrograms per liter or 

nanograms per liter), exposure is often chronic, spanning 

entire life cycles. Many of the OWCs sampled in this study are 

known or suspected endocrine-disrupting chemicals (EDCs), 

meaning they possess hormone-like activity that can disrupt 

normal endocrine function. EDCs have been shown to disrupt 

sexual development, brain development, and the immune 

system, among others (Vandenberg and others, 2012). In 

aquatic environments, EDCs and other OWCs usually occur 

as complex mixtures, which may have additive or synergistic 

effects (Sumpter and Jobling, 1995; Marinovich and others, 

1996; Thorpe and others, 2001; U.S. Environmental Protection Agency, 2003; Vandenberg and others, 2012). Chronic, 

multigenerational exposure of low-concentration mixtures of 

OWCs may result in incremental and irreversible impacts to 

aquatic communities (Daughton and Ternes, 1999). 

In 2006, the U.S. Geological Survey (USGS) and the 

Milwaukee Metropolitan Sewerage District (MMSD) began a 

cooperative study of OWCs in Milwaukee area streams and in 

the Milwaukee Harbor. The goal of the study was to provide 

an assessment of OWCs and toxicity in different stream 

compartment and flow regimes, including surface water during 

base flow and stormflow, streambed pore water, and streambed 

sediment. During 2006–9, 196 samples were collected from 

17 sites: 14 stream sites, 2 harbor sites, and 1 stream/harbor 

transition site (table 1; fig. 1). Water samples were analyzed 

for 69 OWCs; sediment samples were analyzed for 57 OWCs. 

Additionally, water column, pore-water, and sediment samples 

from the 14 stream sites were analyzed for aquatic toxicity 

(AqT) using bioassays.

This study can assist watershed managers in prioritizing management and remediation efforts by describing 

OWC occurrences at different sites and in different stream 

compartments and flow regimes, and by identifying frequently occurring compounds and their potential toxicity to 

aquatic communities. 

Purpose and Scope

This report presents results of an assessment of OWCs 

and AqT in different stream compartments (stream water, 

sediment pore water, and bed sediment) and flow regimes 

(stormflow and base flow) in aquatic ecosystems within the 

MMSD service area. Occurrence and concentrations of OWCs 

are analyzed by sampling site, stream compartment, and flow 

regime. AqT is assessed by comparing measured concentrations to benchmark values, and by bioassays. This study was 

part of the Watercourse Corridor Study—Phase III, a cooperative effort among the MMSD, WDNR, SEWRPC, USGS, and 

local universities. Data from this study builds on data collected 

during 2004–5 as part of the Watercourse Corridor Study—

Phase II (Thomas and others, 2007).

Description of Study Area 

Most sampling sites were within the MMSD planning 

area. In total, 17 sites were sampled: 14 stream sites, 2 sites in 

the Milwaukee Harbor (Middle Harbor Milwaukee Outer Harbor Site (OH-03) and Middle Outside Harbor Breakwater Lake 

Site (OH-14)), and 1 stream/harbor transition site (Milwaukee 

River at the mouth at Jones Island (MRJ)). The stream/harbor 

transition site, MRJ, receives water from the Milwaukee, Kinnickinnic, and Menomonee River watersheds, as well as Lake 

Michigan. Basin-drainage areas of the stream sites (including 

MRJ) range from 9.56 to 872 square miles (mi2), with annual 

mean discharges from 13.2 to 735 cubic feet per second 

(ft3/s) (Scudder Eikenberry and others, 2010; U.S. Geological 

Survey, 2011). The sampled basins span a broad range of land 

uses and urban influence, with 10.4 to 96.0 percent urban land 

use. Of the harbor sites, OH-14 is located outside the break 

wall and OH-03 is located inside the break wall, approximately midway between the break wall and the mouth of the 

Milwaukee River. 
Introduction 

3

Table 1. Site characteristics, land use, and types of samples collected, southeast Wisconsin, 2006–9. [USGS, U.S. Geological Survey; mi2, square mile; ft3/s, cubic foot per second; natural areas include forests, grasslands, wetlands, and shrublands, among others; OWC, organic waste compound; AqT, aquatic toxicity, samples were collected one time, where indicated; --, not sampled; na, not available; land use percentages calculated from National Land Cover Database, 2001, and Southeastern Wisconsin Regional Planning Commission, 2000]

USGS 

site 

name

Site 

abbreviation

USGS 

station 

number

Site characteristics and land use

Type of 

samples 

collected

Number of samples collected 

for OWCs

Drainage 

area 

(mi2)

Mean 

annual 

discharge 

(ft3/s)

Percent 

urban

Percent 

agricultural

Percent 

natural 

areas

Base 

flow

Stormflow Pore water Sedi- ment

Streams sampled at low intensity

Milwaukee River at Milwaukee MRM 04087000 696 442 19 50 31 OWC, AqT 1 -- 1 1Root River near Franklin RRF 04087220 49.2 44.8 68 11 21 OWC, AqT 1 -- 1 1Menomonee River at Menomonee Falls MMF 04087030 34.7 31.5 35 38 27 OWC, AqT 1 -- 1 1Willow Creek at Maple Road, near Germantown WCG 040870195 6.33 na 34 37 28 OWC, AqT 1 -- 1 1Parnell Creek near Dundee PCD 04086175 9.35 na 3 26 71 OWC, AqT 1 -- 1 1

Streams sampled at middle intensity

Lincoln Creek 47th Street at Milwaukee LCM 040869415 9.56 13.2 89 0 11 OWC, AqT 9 -- 1 2Little Menomonee River at Milwaukee LMM 04087070 19.7 18 41 34 26 OWC, AqT 10 -- 2 4Underwood Creek at Wauwatosa UCW 04087088 18.2 15.2 84 1 15 OWC, AqT 9 -- 1 3Honey Creek at Wauwatosa HCW 04087119 10.3 15.2 96 0 4 OWC, AqT 9 -- 1 3Root River at Grange Avenue, at Greenfield RRG 04087214 14.7 17.3 86 1 14 OWC, AqT 9 -- 1 3

Streams sampled at high intensity

Menomonee River at Wauwatosa MRW 04087120 123 107 61 19 20 OWC, AqT 9 12 1 3Kinnickinnic River at S. 11th Street, at Milwaukee KRM 04087159 18.8 25.3 93 1 7 OWC, AqT 9 11 1 3Oak Creek at South Milwaukee OSM 04087204 25 23.9 58 18 24 OWC, AqT 9 10 1 3Milwaukee River near Cedarburg MRC 04086600 607 453 13 55 32 OWC, AqT 9 6 1 3

Stream/harbor transition and harbor sites

Milwaukee River at the mouth at Jones Island MRJ 04087170 872 727 30 43 28 OWC 9 -- -- --Middle Harbor Milwaukee Outer Harbor Site OH-03 430134087532900 na na na na na OWC 8 -- -- --Middle Outside Harbor Breakwater Lake Site OH-14 430138087514800 na na na na na OWC 8 -- -- --
4 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Milwaukee

Sheboygan

Waukesha

Cedarburg

MRW

HCW

UCW

LCM

LMM

MRC

KRM

MRJ

OH-03

OH-14

RRG

OSM

RRG

KRM

HCW MRJ

OH-03

OH-14

LMM

LCM

UCW

MRC

SHEBOYGAN

FOND DU LAC

DODGE

WASHINGTON

OZAUKEE

MILWAUKEE

WAUKESHA

WASHINGTON

DODGE

FOND DU LAC

SHEBOYGAN

Lake

Michigan

MRM

RRF RRF

MMF

WCG

PCD

0 5 10 MILES

0 105 KILOMETERS

EXPLANATION

Land use

Residential

Commercial

Industrial

Transportation

Other urban

Agriculture, general

Forests, grasslands, and other 

 natural areas

Milwaukee Metropolitan Sewerage

District planning area boundary

Sampling site

Open water

Cloud cover

Sampling site drainage area boundary

County boundary

Watershed boundary

(colors outside watershed are masked)

43o20'

43o10'

42o50'

43o

43o30'

43o40'

88o40' 88o30' 88o20' 88o10' 88o 87o50' 87o40'

Base composited from Southeastern Wisconsin Regional Planning Commission digital land use inventory, 1:4,800, 2000;

Wisconsin Department of Natural Resources WISCLAND land cover, 1:40,000, 1998; National Hydrologic Dataset Waterbody, 

1:24,000, 2010; Wisconsin Transverse Mercator Projection, referenced to North American Datum of 1983, 1991 adjustment. 

Wisconsin

Figure 1. Location of sampling sites, drainage basins, and land-use areas used in the study. (Sampling site abbreviations are defined 

in table 1.)
Water and Sediment Sampling: Design and Collection 5

Water and Sediment Sampling: Design 

and Collection 

Whole-water and sediment samples were collected for 

analysis of OWCs as well as for AqT bioassays. Sampling for 

OWCs was conducted during 2007–9, and was a collaborative 

effort between USGS and MMSD field personnel. Sampling 

for AqT was conducted during May 2006 and July–August 

2007. Table 1 outlines the types and numbers of samples collected at each of the 17 sites.

Sampling Design

The 17 sites were sampled at different intensities, 

and at some sites only certain sample types were collected 

(table 1). Of the 14 stream sites, 5 were sampled at low 

intensity: 1 base-flow water column, 1 streambed pore-water, 

and 1 streambed-sediment sample per site, all analyzed for 

both OWCs and AqT. These sites were Milwaukee River 

at Milwaukee (MRM), Root River near Franklin (RRF), 

Menomonee River at Menomonee Falls (MMF), Willow 

Creek at Maple Road, near Germantown (WCG), and Parnell 

Creek near Dundee (PCD). Another five of the stream sites 

were sampled at middle intensity, with the same sampling 

schedule as the low-intensity sites but with additional OWC 

samples of streambed sediment and base-flow water column. 

The middle-intensity stream sites were Lincoln Creek 47th 

Street at Milwaukee (LCM); Little Menomonee River at 

Milwaukee (LMM); Underwood Creek at Wauwatosa (UCW); 

Honey Creek at Wauwatosa (HCW); and Root River at Grange 

Avenue, at Greenfield (RRG). The 4 high-intensity stream 

sites—Menomonee River at Wauwatosa (MRW); Kinnickinnic River at South 11th Street, at Milwaukee (KRM); Oak 

Creek at South Milwaukee (OSM); and Milwaukee River near 

Cedarburg (MRC)—followed the same sampling schedule as 

the middle-intensity sites, but with the addition of 6–12 stormflow samples collected for OWC analysis. At the two harbor 

sites (OH03 and OH14) and the stream/harbor transition site 

(MRJ), samples were collected from the water column only, 

and analysis was limited to OWCs. 

All streambed-sediment and streambed pore-water 

samples were collected during spring and summer months, 

as were the 1 to 2 base-flow water-column samples analyzed 

for both OWCs and AqT. At the middle- and high-intensity 

stream sites, base-flow water-column samples for OWCs were 

collected quarterly, for a total of 9 to 10 samples over a 2-year 

period. At the high-intensity stream sites, stormflow watercolumn OWC samples were collected based on availability of 

runoff events rather than on a set schedule. Runoff events were 

less frequent at the more rural site (MRC) allowing collection of fewer stormflow samples than at the more urban sites. 

A total of 6–12 stormflow samples were collected per highintensity sampling site. 

Sample-Collection Methods

In accordance with USGS protocols (U.S. Geological 

Survey, variously dated), samples were collected and processed in a manner consistent with minimal contamination of 

organic compounds. Glass, Teflon, or stainless-steel equipment 

was used during sample collection and processing, whenever 

possible. Water samples were neither filtered nor acidified. 

Samples were sent to the USGS National Water Quality Laboratory (NWQL) for analysis of OWCs and to the Wisconsin 

State Laboratory of Hygiene for AqT bioassays.

Base-flow water-column samples from stream sites were 

collected using the equal-width-increment (EWI) method 

(Edwards and Glysson, 1999). Approximately 10 subsamples 

were collected at equal widths across the stream cross section 

using a DH-81 with a Teflon nozzle and a 1liter (L) Teflon 

bottle. Subsamples were composited in a 14-L Teflon churn 

and then churned into a 1L baked amber-glass bottle for 

analysis. At the three harbor and stream/harbor transition sites, 

samples were collected using a single dip of the baked amberglass bottle. 

Stormflow samples were collected using refrigerated 

automated samplers with Teflon-lined sample lines and up to 

four 10-L glass bottles. The automated samplers were controlled by dataloggers programmed to collect flow-weighted 

composites throughout the storm-runoff period. The 10-L 

bottles were composited in a Teflon churn and then the sample 

was churned into a 1-L baked amber-glass bottle for analysis. 

Streambed pore water was collected by inserting a vented 

Teflon probe 10–15 centimeters (cm) into the sediment and 

using a peristaltic pump to pull the surrounding pore water out 

through the vents, as described in Lutz and others (2008). An 

acrylic disc was attached to the sampler, and the sampler was 

inserted to the point where the disc made contact with the top 

of the bed sediment. This disc helped to minimize intrusion 

into the pore water from the water column during sampling. At 

each site, subsamples of approximately 2 L of pore water were 

collected at three to five locations, composited in a 14L Teflon 

churn, and then churned into a 1-L baked amber-glass bottle. 

Streambed sediment was collected by inserting a 2-inch 

(in.) diameter Teflon core approximately 2 in. into the sediment, inserting a stiff Teflon sheet under the bottom of the 

core, and gently lifting the sheet and core out of the water. 

Sediment was collected at three to five locations per site, composited in a stainless-steel bucket, and mixed with a stainlesssteel spoon. Fine sediments (silts) were targeted at all sites, 

when available. Sediment samples for OWC analysis were put 

through a stainless-steel sieve using a stainless-steel spoon to 

remove any gravel or large organic debris. The AqT samples 

were not sieved. After being composited, the sediment samples 

were put in baked amber-glass bottles for analysis. 
6 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Analytical Methods

Following collection, whole-water and sediment samples 

were shipped on ice overnight to the USGS NWQL for 

analysis of OWCs (analysis schedule 4433 for water and 5433 

for sediment samples), and delivered to the Wisconsin State 

Laboratory of Hygiene for bioassay toxicity tests. 

Organic Waste Compounds

Whole-water and sediment samples were analyzed at 

the NWQL for 69 and 57 compounds, respectively (table 2, 

in back of report). The compounds were chosen because they 

are good indicators of domestic or industrial wastewater, 

and (or) because they are associated with human or environmental health risks (Kolpin and others, 2002; Zaugg and 

others, 2007). Approximately one-third of the compounds 

are known or suspected endocrine disruptors (The Endocrine 

Disruption Exchange, Inc., 2011). 

Compounds in water samples were extracted using 

continuous liquid-liquid extraction and methylene chloride 

solvent, then determined by capillary-column gas chromatography/mass spectrometry (GC/MS; Zaugg and others, 2007). 

Compounds in sediment samples were extracted using a 

pressurized solvent-extraction system, then determined by 

capillary-column GC/MS (Burkhardt and others, 2006).

The NWQL spikes of these compounds in reagent and 

surface water, and in sand, river sediment, and topsoil, show 

variable recovery performance. Percent recovery and variability data for each compound are listed in Zaugg and others 

(2007) and Burkhardt and others (2006). 

For most compounds, the NWQL sets the reporting limit 

(RL) at 2–10 times higher than the minimum detection limit 

(MDL; table 2; Oblinger Childress and others, 1999). The 

RLs may be elevated because of interferences, especially in 

sediment samples. Reasons for interferences are discussed in 

Zaugg and others (2007) and Burkhardt and others (2006). 

Measured concentrations below the RL are still reported by the 

lab but are assigned an “estimated” (“E”) qualifier. The “E” 

qualifier also may be assigned if the concentration is below 

the lowest calibration standard [(usually 0.2 micrograms per 

liter (μg/L)], or if there are matrix interferences. Further, some 

compounds have been permanently assigned an “E” qualifier because historically quality-assurance criteria have not 

been met. In terms of qualitative identification of a compound 

(detection as opposed to nondetection), results with the “E” 

qualifier generally can be considered reliable, with reliability 

decreasing as the measured concentration nears or falls below 

the MDL (Oblinger Childress and others, 1999; Zaugg and 

others, 2007). In this report, concentrations reported with the 

“E” qualifier are considered detections. 

Bioassays for Toxicity Testing in Sediment

Sediments were tested for toxicity along with formulated 

laboratory sediment as the laboratory control. Solid-phase 

sediment-toxicity tests were performed using the amphipod, 

Hyalella azteca, and the larval stage of the midge, Chironomus 

tentans (C. tentans). These two organisms, which burrow and 

come into direct contact with the sediments, are recommended 

by the U.S. Environmental Protection Agency (EPA) for use 

in sediment-toxicity testing (U.S. Environmental Protection 

Agency, 1994). 

Sediments were stored at 4 degrees Celsius (°C) in the 

dark. Prior to testing, the sediment was thoroughly homogenized (by mixing) using a large stainless-steel spoon. A 

synthetic laboratory-control sediment was prepared containing 77 percent sand, 17 percent clay, 5 percent organic matter 

(composted cow manure), and 1 percent buffer (calcium 

carbonate). Homogenized sediment was placed in test beakers 

with dechlorinated tap water, with a sediment to overlying 

water ratio of 1:1.75. After allowing the sediments to settle for 

24 hours, organisms were randomly added to the test beakers. 

Test beakers were randomly placed in a walk-in environmental 

chamber at 23 ± 1°C with a 16:8-hour light:dark cycle. Test 

conditions are summarized in appendix 1.

Juvenile Hyallela azteca (H. azteca) and larval C. tentans

were ordered from Aquatic Research Organisms (Hampton, 

New Hampshire) to be the appropriate age at test initiation 

(7–14 days old for H. azteca and 9 days old for C. tentans). 

Ten individuals were randomly placed in each 400 milliliter (mL) polypropylene test beaker with eight replicates per 

sediment site. Overlying water was replaced twice daily, and 

organisms were fed daily (1.5 mL yeast/fish food/cereal leaves 

(YFC) leaves for H. azteca and 4 milligrams Tetramin® flake 

fish food for C. tentans). Dissolved oxygen, pH, and temperature of the overlying water were recorded daily. On day 10, 

the organisms were recovered from the sediment to determine 

the number of survivors in each replicate. The organisms then 

were subjected to ultraviolet (UV) light for a period of 2 hours 

following the procedure for PAH photoactivation described by 

Ankley and others (1994). This procedure at times can provide 

information on additional adverse impacts owing to PAH 

photoactivation in the organisms. Surviving individuals were 

transferred to 100 mL beakers containing 30 mL of dechlorinated tap water. The beakers were set below the UV bulbs 

(UVA-340, Q-Panel Lab Products, Cleveland, Ohio, USA) so 

that the bottom of each beaker was approximately 8.5 cm from 

the bottom of the UV bulb. After 2 hours of UV exposure, the 

beakers were removed to record post-UV survival. One replicate from each treatment was kept away from the UV light 

during the 2-hour exposure to serve as controls. Both surviving and dead organisms then were removed from the beakers 

and placed in tared aluminum weigh pans to determine dry 

weight. Pans were placed in an oven for a minimum of 2 hours 

at 110°C prior to weighing. C. tentans then were ashed at 

550°C overnight to determine ash-free dry weight. The weight 

of inorganic material (ash weight) was subtracted from the 
Data Analysis 7

total dry weight to determine weight of organic matter. Survival and ash-free dry weight were used as final endpoints for 

C. tentans test. Ash-free dry weight is referred to as “weight” 

throughout this report. Survival and dry weight were used as 

final endpoints for H. azteca tests.

Bioassays for Toxicity Testing in Water

Surface- and pore-water samples were stored at 4°C upon 

delivery from the field. Aliquots were removed daily to prepare test solutions. Samples were warmed in a water bath to 

the appropriate test temperature. Toxicity tests were performed 

without dilution using the C. dubia chronic test (U.S. Environmental Protection Agency, 2002). Test-chamber conditions 

were 25°C with a 16:8-hour light:dark cycle. The organisms 

were fed with each daily renewal a combination of YFC and 

the green algae Selenastrum capricornutum. Production of 

young was recorded daily, and the tests were terminated after 

80 percent of controls released their third brood (6 to 7 days). 

Survival and production of young (reproduction) were used as 

final endpoints for this test.

Additionally, pore-water samples were assayed using a 

48-hour H. azteca acute test. Each treatment consisted of 10 

replicates, each containing 2 H. azteca organisms in 30 mL of 

water and 1 square centimeter (cm2) of Nitex® mesh for substrate. Organisms were fed YFC daily. Survival was recorded 

at the end of the 48-hour exposure and was used as the final 

endpoint for this assay. 

Quality Assurance/Quality Control 

Quality-assurance/quality-control (QA/QC) samples were 

collected during both laboratory and field activities to assess 

data quality and identify possible contamination. The NWQL 

QA/QC samples included blanks, reagent spikes, and surrogates. A blank consists of analyte-free water that is analyzed 

alongside environmental samples to ensure there is no contamination from the lab. A reagent spike is water with a known 

concentration of the analytes being measured. A reagent spike 

also is analyzed alongside environmental samples to measure the performance of the analytical methods. At least one 

laboratory blank and reagent spike accompany each set of 18 

or fewer environmental samples being analyzed at the NWQL 

(Zaugg and others, 2007). 

Surrogates are compounds that are physically and (or) 

chemically similar to the other compounds being measured. 

The NWQL adds surrogate compounds to each OWC sample 

prior to analysis. Surrogate recovery rates, reported as percentages, are used to measure the accuracy of the analytical 

method and identify sample-processing problems and matrix 

effects. The four surrogates added to water samples were 

bisphenol A-d3, caffeine-13C, decafluorobiphenyl, and fluoranthene-d10, with median recovery rates of 84, 75, 60, and 

74 percent, respectively. Overall, the recovery rates in water 

samples ranged from 13 to 162 percent, with a median of 71 

and standard deviation of 21. The same surrogates were added 

to OWC sediment samples, minus caffeine-13C. Median 

recovery rates in sediment samples were 83 for bisphenol 

A-d3, 23 for decafluorobiphenyl, and 82 for fluoranthened10. Overall, the recovery rates in sediment samples ranged 

from 0 to 266 percent, with a median of 60 and standard 

deviation of 44. 

Field QA/QC activities consisted of one replicate watercolumn sample collected for OWCs during base-flow conditions at MRC. A replicate sample is collected concurrently 

with an environmental sample to determine the variability in 

sample-collection and processing procedures. Of the 69 comparisons (compounds) between the 2 samples, 10 compounds 

were detected in both samples; for 9 of those compounds, the 

detections were below 0.2 μg/L. The tenth compound, cholesterol, had estimated detections of 0.45 and 0.89 μg/L, for 

a relative percent difference of 66. For 22 compounds, there 

were estimated detections in 1 sample but not the other, but 

in only 5 of those were the detections greater than 0.2 μg/L, 

and those were still below the reporting level as set by the 

other sample. 

No OWC field blanks were collected for this study. The 

lack of field blanks decreases confidence in the concentrations 

detected in the environmental samples, especially detected 

concentrations at or below the RL. Other studies sampling 

OWCs have reported low concentration detections of a 

number of compounds in field blanks, including naphthalene, 

phenanthrene, benzo[a]pyrene, benzophenone, bisphenol A, 

methyl salicylate, N,N-diethyl-meta-toluamide (DEET), isophorone, phenol, 4-Nonylphenol (sum of all isomers; hereafter 

NP), triphenyl phosphate, and Tris(2-chloroethyl) phosphate 

(Phillips and others, 2005; Phillips and Chalmers, 2009; Wilkison and others, 2002; Kingsbury and others, 2008). Three of 

these compounds stand out as having fairly high (greater than 

25 percent) detection frequencies in base-flow samples in this 

study: phenanthrene (51 percent), DEET (58 percent), and Tris 

(2-chloroethyl) phosphate (42 percent). Therefore, low-concentration detections of these compounds, as well as others, 

should be cautiously interpreted.

Data Analysis

Organic Waste Compounds

Individual OWC compounds were aggregated into 

15 classes: antioxidants, dyes and pigments, fire retardants, 

PAHs, plasticizers, fuels, solvents, herbicides, insecticides, 

antimicrobial disinfectants, detergent metabolites, flavors 

and fragrances, human drugs (nonprescription), sterols, and 

miscellaneous (table 2). The classes are consistent with those 

used in the Watercourse Corridor Study—Phase II (Thomas 

and others, 2007), and were originally based on aggregations 

by Sullivan and others (2005). 
8 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

A number of the analyses in this report are based on 

whether or not compounds were detected in the environmental samples. Results reported as “estimated” were considered detections, regardless of their concentration. Detection 

frequencies were analyzed for individual compounds as well 

as for classes of compounds. For individual compounds, 

detection frequencies were computed as the percentage of 

samples with detections of those compounds. For classes, 

detection frequencies were determined by whether any one of 

the compounds in a class was detected in a given sample. For 

example, if any one of the six compounds in the PAH class 

were detected in a sample, that would be considered a detection of the PAH class. 

Analyses in this study use estimated concentrations at 

their reported value, whether above or below the RL for that 

compound. Median, mean, and maximum detected concentrations were computed for individual compounds using detected 

concentrations only. Class concentrations were computed for 

each sample by summing the detected concentrations within 

each class, using zeros for compounds without detections. 

Total sample concentrations were computed by summing all 

detected concentrations, using zeros for compounds without 

detections. Inadequate sample numbers prevented the use 

of nondetect-estimation methods such as those described by 

Helsel (2012). 

To assess how the total concentration of each compound 

class varied by sample type, total class concentrations were 

computed for each sample using detected concentrations only, 

with zeros for nondetections. The total class concentrations 

then were averaged by site to give equal weight to each site, as 

different sites had different numbers of samples. 

A subset of 20 compounds considered to be domesticwastewater indicators was analyzed to assess contributions 

from that source. These are compounds commonly associated 

with sanitary-sewer and septic-system leaks and overflows, 

though other sources are possible. These compounds are 

indicated in table 2 and include all of the fire retardants and 

detergent metabolites, most of the flavors/fragrances, and the 

antimicrobial disinfectant triclosan. Total concentrations of 

these 20 domestic-wastewater indicator compounds were computed by summing the detected concentrations in each sample, 

using zeros for nondetections. 

The AqT criteria and guidelines (hereafter cumulatively referred to as benchmarks) for OWCs were compiled 

and compared to concentrations in environmental samples. 

For the majority of the compounds in this study, AqT 

benchmarks have not been established. Benchmarks from 

the EPA and other sources, such as the Canadian Council 

of Ministers of the Environment were found for 25 of the 

compounds sampled. 

Toxicity quotients (TQ) were computed for individual 

OWC compounds with AqT benchmarks. The TQ provides a 

unitless measure of the scale of the benchmark exceedance, 

and is computed by dividing the measured concentration of 

a compound by the lowest of the compound’s benchmarks. 

mean) then were computed for each 

compound, using samples with detected concentrations only. 

The potential combined toxicity of the six PAH compounds was assessed using an equilibrium-partitioning 

method developed by the EPA (U.S. Environmental Protection Agency, 2003; 2010). Using the measured concentrations 

and compound-specific multipliers and divisors, acute- and 

chronic-potency ratios are computed for each PAH compound in a sample. The potency ratios then are summed for 

an acute- and chronic-potency factor, which if greater than 

1.0 indicates potential toxicity to aquatic organisms. Because 

only 6 PAH compounds were analyzed in this study, rather 

than the 27 compounds used in the EPA method, and because 

the potency ratios for each compound are additive, the 

resulting potency factors likely are conservative. Based on a 

previous study, which analyzed 17 PAHs in sediment at these 

same streams (Corsi and others, 2011), it is estimated that the 

potency factors presented in this study likely would be 1.4 to 

1.6 times greater had the same 17 PAHs been sampled.

The OWC-focused analyses in this report omit samples 

from the five low-intensity sampling sites (MRM, RRF, MMF, 

WCG, and PCD) because of the low sample numbers at those 

sites (table 1). This includes all analyses discussed in the section titled “Occurrence of OWCs.” These sites are included 

in analyses focused on the AqT bioassays, in the section titled 

“Adverse Impacts on Aquatic Life.” 

Mean toxicity quotients (TQ

Toxicity in Stream Compartments 

Resulting toxicity endpoints were normalized by the 

laboratory-control results and presented as a percent of laboratory control. Standard errors of replicates are presented on all 

graphs as a representation of uncertainty in bioassay sample 

results. A specific threshold of adverse effect is difficult to 

define owing to many factors that influence aquatic organisms. 

An adverse effect is likely if the result is below 50 percent; if 

the value falls between 100 and 50 percent, the likelihood of 

an adverse effect increases with a decreasing value. Examination of the range of the error bars on the graphs also can 

provide information on the likelihood of differences in sample 

results from the laboratory control (overlapping with 100 percent) and from other samples (overlapping with corresponding-error bars). For sediment-toxicity results, likely adverse 

effects were observed, so further analysis was done to explore 

association with the corresponding OWC-sample results. 

These sediment OWC-sample results were aggregated by 

chemical class as previously discussed. Concentrations could 

not be compared directly among categories for association 

to the AqT data because consistent toxicity-benchmark data 

were not available from comparable laboratory testing for the 

various OWC compounds, and the actual concentration levels 

that could possibly affect AqT in different categories likely are 

very different. As an attempt to address this inconsistency, the 

sites were given a ranking from lowest to highest concentration for each OWC category that was considered a potential 
Occurrence of Organic Waste Compounds 9

contributor to toxicity. This included the following categories: 

detergent metabolites, fire retardants, fuel, insecticides, PAHs, 

and solvents. Rank summations were computed for all one, 

two, and three class combinations of these rankings. Scatter 

plots and Pearson correlation coefficients of the rank summations as compared to C. tentans weight were generated for 

final analysis. For example, when considering three of the 

categories to explain bioassay results, the rankings for the 

three categories were summed for each site giving a potential 

rank-sum from 3 to 42. Lacking consistent toxicity-benchmark 

data among different categories precluded more sophisticated and relevant analysis such as a summation of toxicity 

units (ratio of sample concentrations to toxicity-benchmark 

concentrations). 

Occurrence of Organic Waste 

Compounds

At least 1 compound was detected in all 196 samples 

collected with as many as 41 of the 69 compounds detected in 

1 of the stormflow samples (table 3). As a group, the baseflow samples had the lowest detection rate, with a median 

of 12 compounds detected per sample. The stormflow and 

pore-water samples had medians of 26 and 28 detections per 

sample, respectively. The sediment samples had a median of 

22 detections per sample but were tested for only 57 compounds instead of 69. Figure 2 shows the percent of compounds detected for samples collected at the middle- and 

high-intensity sampling sites. 

Detection Frequencies of Classes of OWCs

Of the 69 compounds analyzed, 64 were detected in at 

least 1 sample (all sample types combined), and all 15 of the 

classes were detected [(tables 4a, 4b, 5a, and 5b (in back of 

Table 3. Detection statistics for organic waste compounds, by sample type, all sites combined, southeast Wisconsin, 2006–9.

Sample type Number of 

samples

Number of 

compounds 

analyzed

Minimum 

number of 

compounds 

detected, 

per sample

Median number of 

compounds detected, 

per sample

Maximum number of 

compounds detected, 

per sample

Base flow 107 69 1 12 37

Stormflow 39 69 11 26 41

Pore water 10 69 18 28 37

Sediment 28 57 7 22 28

report)]. The five compounds not detected in any sample are 

all from different classes. 

The base-flow samples had class-detection frequencies 

from 25 to 75 percent for all but two classes (fig. 3). The two 

classes with base-flow detection frequencies above 75 percent were PAHs (80 percent) and herbicides (88 percent). 

None of the classes had base-flow detection frequencies 

below 25 percent. 

At the four high-intensity sampling sites—MRC, MRW, 

OSM, and KRM—class-detection frequencies in stormflow samples averaged 1.3 to 2.0 times higher than those in 

base-flow samples. Eleven of the 15 classes had stormflowdetection frequencies above 75 percent, and 5 classes (dyes/

pigments, PAHs, solvents, herbicides, and insecticides) had 

stormflow-detection frequencies above 90 percent. The only 

class with a stormflow-detection frequency below 25 percent 

was the miscellaneous class (fig. 3). These results indicate that 

urban storm water is an important source of OWCs to Milwaukee area streams. 

The pore-water samples, which were collected during 

base-flow conditions, had higher detection frequencies than 

base-flow samples for all classes except human drugs. The 

three compounds in the human-drug class were not detected 

in pore-water samples. Ten of the 15 classes had pore-water 

detection frequencies above 75 percent, and 7 classes (antioxidants, dyes/pigments, PAHs, fuels, herbicides, insecticides, 

and flavors/fragrances) had pore-water detection frequencies 

above 90 percent. Human drugs was the only class with a 

pore-water detection frequency below 25 percent.

None of the classes had sediment-detection frequencies 

in the range of 25 to 75 percent, a notably different occurrence distribution from the base-flow samples. Ten of the 

15 classes had sediment-detection frequencies of 75 percent or 

above, and 7 classes (dyes/pigments, PAHs, fuels, insecticides, 

antimicrobial disinfectants, flavors/fragrances, and sterols) had 

detection frequencies above 90 percent. Five of the classes had 

sediment-detection frequencies below 25 percent, and two of 

those (herbicides and nonprescription human drugs) were not 

detected in sediment samples. 
10 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

0

10

20

30

40

50

60

Percent of compounds detected

0

10

20

30

40

50

60

0

10

20

30

40

50

60

10

20

30

40

50

60

Milwaukee River near Cedarburg Little Menomonee (LMM)

(MRC)

Underwood Creek (UCW) Honey Creek (HCW) Menomonee River (MRW)

Kinnickinnic River

(KRM)

Oak Creek (OSM) Root River at Greenfield (RRG)

Milwaukee River at mouth (MRJ) Middle Harbor (OH-03) Outside Harbor (OH-14)

Lincoln Creek (LCM)

Pore

water

StormflowBase

flow

Sediment Pore

water

StormflowBase

flow

Sediment Pore

water

StormflowBase

flow

Sediment

NA NA NA NA NA NA NA NA NA

NA NA

NA NA

NA

0

horizontal lines mark medians; NA, no samples collected)

Figure 2. Percent of compounds detected per sample, organized by site and sample type. (Site abbreviations are defined in table 1; 
Occurrence of Organic Waste Compounds 11

0 0

0

Organic waste compounds

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

Antioxidants

Dyes/pigments

Fire retardants

Polycyclic aromatic hydrocarbons

Plasticizers

Fuels

Solvents

Herbicides

Insecticides

Antimicrobial disinfectants

Detergent metabolites

Flavor/fragrances

Human drugs, non prescription

Sterols

Miscellaneous

Base-flow samples (n = 107)

Stormflow samples (n = 39)

Pore-water samples (n = 10)

Sediment samples (n = 28)

Frequency of detection, in percent

Figure 3. Frequency of detection of organic waste compounds, by class, for each sample type. (n, number of samples; 0, no 

detections)
12 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Several of the classes with low sediment-detection frequencies had high-detection frequencies in the water samples, 

especially herbicides and fire retardants. The one class in 

which the sediment samples had a markedly higher-detection 

frequency than the water samples was the antimicrobial disinfectants, with detection frequencies of 96 percent in sediment 

samples and 50 percent or below in water samples. The highdetection frequency of antimicrobial disinfectants in sediment 

samples can be attributed to the wood preservative p-Cresol. 

The source of p-Cresol may be creosote-treated railroad ties 

and guardrail posts (Thomas, 2009).

The PAHs were the most frequently detected class 

overall, occurring in 100 percent of the stormflow, pore-water, 

and sediment samples, and in 80 percent of the base-flow 

samples. In the stormflow, pore-water, and sediment samples, 

all six of the PAH compounds had detection frequencies above 

60 percent, and four had detection frequencies ranging from 

90 to 100 percent. Overall, the miscellaneous class was the 

least-frequently detected. 

Detection Frequencies of Individual OWCs

Detection frequencies for some classes were dominated by only one or two of the compounds within that 

class. Two of the three compounds in the antioxidants class 

had low-detection frequencies (0 to 40 percent), but the 

third compound, Bisphenol A, was detected in more than 

75 percent of all stormflow, pore-water, and sediment samples 

(tables 4a, 4b, 5a, and 5b). Detections in the plasticizers class 

(five compounds) were dominantly DEHP (sediment samples) 

and Tris(2-chloroethyl) phosphate (all water-sample types). 

Four of the six compounds in the insecticides class had detection frequencies below 20 percent; the high-detection frequency of insecticides can be attributed to Carbazole and, to a 

lesser extent, DEET. The detergent metabolite-class detections 

were mostly NP (4-Nonylphenol, also used in pesticide and 

asphalt formulations) and, to a lesser extent, 4-Cumylphenol. In the nonprescription human-drug class, base-flow and 

stormflow-detection frequencies were mostly caffeine.

For some of the classes, most or all of the compounds 

were detected at high frequencies. All six of the PAH compounds (anthracene, benzo[a]pyrene, fluoranthene, naphthalene, phenanthrene, and pyrene) had very high-detection 

frequencies in stormflow, pore-water, and sediment samples, 

and three of the six had high-detection frequencies in baseflow samples (tables 4a, 4b, 5a, and 5b). Three of the four 

compounds in the fuels class (1-Methylnapthalene, 2-Methylnapthalene, and 2,6Dimethylnapthalene) were detected in 

the majority of stormflow, pore-water, and sediment samples. 

Detection frequencies for all compounds and sample types are 

listed in tables 4a, 4b, 5a, and 5b.

Concentrations of OWCs

The median detected concentrations of most compounds 

were higher in stormflow and pore-water samples than in 

base-flow samples. Median concentrations in stormflow 

samples were greater than those in base-flow samples by a 

factor of 2 or more for 23 compounds and by a factor of 10 or 

more for 5 compounds (fluoranthene, phenanthrene, pyrene, 

isophorone, and acetophenone; tables 4a, and 4b), indicating 

that urban runoff is likely a source of many of the compounds 

to the stream. Conversely, median concentrations in baseflow samples were greater than those in stormflow samples 

by a factor of two or more for three compounds: dichlorvos, 

HHCB, and 1,4-Dichlorobenzene. Median pore-water concentrations were comparable to stormflow concentrations for most 

compounds. 

Five compounds had median detected concentrations 

greater than 0.5 μg/L in base-flow samples: the herbicide 

pentachlorophenol, the detergent metabolite 4-Nonylphenol 

diethoxylate, and the sterols beta-sitosterol, beta-stigmastanol, 

and cholesterol (tables 4a, and 4b). The highest detected 

concentration of the base-flow samples was 115 μg/L (estimated), for the non-crop herbicide, dichlorophenyl isocyanate, 

at LMM. The source of the herbicide may have been weed 

control along the railroad, which crosses the stream at the 

sampling location. 

In stormflow samples, 13 compounds had median 

detected concentrations greater than 0.5 μg/L, and 5 compounds had median detected concentrations greater than 

1.0 μg/L: the antioxidant 5-methyl-1H-benzotriazole, the plasticizer DEHP, the solvent isophorone, the detergent metabolite 

4Nonylphenol diethoxylate, and the sterol beta-sitosterol. The 

three compounds with the highest stormflow concentrations 

were all PAHs: fluoranthene (25.6 μg/L, estimated), phenanthrene (26.3 μg/L, estimated), and pyrene (25.6 μg/L, estimated), all from the same KRM sample. 

PAH concentrations in stormflow samples were directly 

related to the percentage of the basin in urban land use (fig. 4). 

The median total PAH (tPAH) concentration from stormflow 

samples at the most urban site (KRM) was 83 times greater 

than at the least urban site (MRC). Likewise, the magnitude 

of the difference between tPAH concentrations in base-flow 

as opposed to stormflow samples appears to be related to the 

percentage of the basin in urban use. The difference between 

the median base-flow and median stormflow concentration at 

MRC was less than 1.0 μg/L (dependent upon value used for 

nondetections), compared to a difference of approximately 

14 μg/L at KRM. 

In pore-water samples, 11 compounds had median 

detected concentrations greater than 0.5 μg/L, and 5 compounds had median detected concentrations greater than 

1.0 μg/L: the PAH fluoranthene, the herbicide dichlorophenyl 

isocyanate, and the sterols beta-coprostanol, beta-sitosterol, 

and cholesterol (tables 4a, and 4b). The compound with the 

highest concentration in pore-water samples was p-Cresol, 

measured at 119 μg/L (estimated) in a sample from HCW. 
Occurrence of Organic Waste Compounds 13

oooooo o oooooo oo o oo

oo oo o o o o o

o o o o o oo

o o

o

xx x xx x

xxxx

x x xxx x

xx x x xx xxx xx x

xxxxxx x x xx x

MRC (13) OSM (58) MRW (61) KRM (93)

0.01

0.1

1.0

10

100

1,000

Total detected concentrations of PAHs, 

in micrograms per liter

Sampling sites from least to most urban 

(Percent of basin in urban land use shown in parentheses)

Stormflow samples

Base-flow samples o x n = 6 9 10 9 12 9 11 9

EXPLANATION

Figure 4. Total detected concentrations of polycyclic aromatic 

hydrocarbons (PAHs) in stormflow and base-flow samples. 

(Nondetections plotted at 0.01 micrograms per liter; horizontal 

lines mark medians; site abbreviations are defined in table 1; 

n, number of samples)

In sediment samples, the median detected concentrations 

of most compounds (36) were less than 100 micrograms per 

kilogram (μg/kg) (tables 5a, and 5b). Eleven compounds had 

median detected concentrations greater than 500 μg/kg, and 

six had median detected concentrations greater than 1,000 μg/

kg: four PAHs (benzo[a]pyrene, fluoranthene, phenanthrene, 

and pyrene) and two sterols (beta-sitosterol and cholesterol). 

Fluoranthene had the highest detected concentration of all 

compounds in sediment samples, measured at 14,900 μg/kg in 

a sample from MRW. 

By summing the detected concentrations within each 

OWC class and for each sample (hereafter referred to as class 

concentrations), some general patterns become apparent. 

Figure 5A and B show maximum class concentrations for each 

sampling location and sample type. Maximum class concentrations above 1 μg/L are much more common in the stormflow and pore-water samples than in the base-flow samples 

(fig, 5A). Herbicide maximum concentrations are uniformly 

high across the three water-sample types, but completely 

undetected in the sediment samples (fig, 5B). Most of the high 

herbicide concentrations can be attributed to one compound, 

dichlorophenyl isocyanate, a noncrop herbicide commonly 

used in urban areas. PAH maximum concentrations are high 

in the stormflow, pore-water, and sediment samples, but less 

than 1 μg/L in the base-flow samples. Solvents have high 

maximum concentrations in the stormflow samples but not in 

any other sample type. Sterols have high, uniform maximum 

concentrations across all sample types and sites. Sterols have 

been shown to be effective tracers of wastewater (Maldonado 

and others, 1999; Wilkison and others, 2002), but they also 

can occur naturally from plants or carnivores. Among the 

water samples, the fuels, human drugs (nonprescription), and 

miscellaneous classes were the only ones with no concentrations greater than 1 μg/L. 

Class concentrations in each sample were averaged, by 

site, to give equal weight to sites with different numbers of 

samples. The resulting site-averaged class concentrations, 

plotted in figure 6, show that for most classes base-flow concentrations tend to be lower than stormflow and pore-water 

concentrations. This is especially true of the PAHs, dyes/

pigments, and solvents. The miscellaneous class is the only 

one for which base-flow class concentrations are greater than 

stormflow class concentrations. This indicates that nonpointsource runoff and (or) wastewater leakage associated with 

storm events may be important sources of OWCs to the 

streams. 

Site-averaged stormflow and pore-water class concentrations are comparable for most classes, with some exceptions 

including plasticizers and solvents, for which stormflow 

concentrations are higher, and flavors/fragrances and the 

miscellaneous class, for which pore-water concentrations are 

higher. In sediment samples, site-averaged class concentrations are highest for the PAHs and sterols and lowest for fire 

retardants, solvents, herbicides (not detected), human drugs 

(not detected), and the miscellaneous class. 

Domestic Wastewater Indicators

Most of the compounds sampled in this study are associated with either nonpoint-source runoff (such as herbicides, 

insecticides, PAHs, and fuels) or industrial or domestic wastewater. To identify OWC contributions primarily from domestic 

human wastewater sources (for example, from leaking sanitary 

sewers and septic systems), a subset of 20 compounds considered to be likely indicators of those sources were analyzed. 

These compounds are indicated in table 2 and include all of 

the fire retardants and detergent metabolites, most of the flavors/fragrances, and the antimicrobial disinfectant triclosan. 

All pore-water and stormflow samples had detections of 

one or more of the domestic wastewater indicator compounds, 

with a median of 5.5 compounds in pore-water samples and 4 

in stormflow samples. Domestic wastewater-indicator compounds were detected in 79 percent of base-flow samples, with 

a median of 2 compounds per sample, and in 89 percent of 

sediment samples, with a median of 3 compounds per sample. 

The maximum number of domestic wastewater-indicator compounds detected in a sample was 11, in a sample from MRJ, 

possibly because of its proximity to the effluent discharge of 

the Jones Island Water Reclamation Facility (wastewater treatment plant), approximately 1,000 feet (ft) away.

The total sample concentrations of the 20 domestic 

wastewater-indicator compounds are plotted by site and 

sample type in figure 7. Samples from most sample types, and 

especially stormflow samples, show a general trend of increasing total concentrations with increasing urban area. Total 

concentrations generally were lower in base-flow samples 

than in stormflow or pore-water samples. For both base-flow 

and stormflow samples, the site with the highest median total 
14 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

. . .

.

.

. .

.

.

.

.

.

.

.

.

.

.

. .

.

.

. . . . .

Stormflow samples Sites (least to most urban, top to bottom)

nAntioxidantsDyes/pigmentsFire retardantsPolycyclic aromatichydrocarbonsPlasticizersFuelsSolventsHerbicidesInsecticidesAntimicrobialdisinfectantsDetergentmetabolitesFlavors andfragrancesHuman drugs,nonprescriptionSterolsMiscellaneous

A

HCW

KRM

MRC

MRW

OSM

RRG

MRC

Base-flow samples

Pore-water samples

1

1

1

1

1

1

6

LCM 1

UCW 1

KRM 11

MRW 12

OSM 10

LCM 9

MRC 9

MRJ 9

LMM 10

OH-03 8

LMM 2

HCW 9

KRM 9

MRW 9

OSM 9

RRG 9

UCW 9

OH-14 8

80−100

60−79

40−59

20−39

1−19

0.99

1.0−9.99

10.0−99.9

100.

0 . <

<

EXPLANATION

Maximum concentration,

in micrograms per liter

Detection frequency,

in percent

Figure 5. Class-detection frequencies and maximum class concentrations for each site. A, Stormflow, base-flow, and pore-water 

samples. B, Sediment samples. (Site abbreviations are defined in table 1; n, number of samples; ≤, less than or equal to; ≥, greater than 

or equal to; <, less than)
Occurrence of Organic Waste Compounds 15

.

.

.

.

.

.

.

. .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

. . .

. . . . .

B

Sediment samples Sites (least to most urban, top to bottom)

AntioxidantsDyes/pigmentsFire retardantsPolycyclic aromatichydrocarbonsPlasticizersFuelsSolventsHerbicidesInsecticidesAntimicrobialdisinfectantsDetergentmetabolitesFlavors andfragrancesHuman drugs,nonprescriptionSterolsMiscellaneous

HCW

KRM

LCM

LMM

MRC

MRW

UCW

3

3

2

4

3

3

OSM 3

RRG 3

3

n

80−100

60−79

40−59

20−39

<100

100−999

1,000−9,999

10,000

0

<

Maximum concentration,

in micrograms per liter

Detection frequency,

in percent

.

EXPLANATION

Figure 5. Class-detection frequencies and maximum class concentrations for each site. A, Stormflow, base-flow, and pore-water 

samples. B, Sediment samples. (Site abbreviations are defined in table 1; n, number of samples; ≤, less than or equal to; ≥, greater than 

or equal to; <, less than)—Continued

concentration was KRM. MRJ had the second highest median 

total concentration among the base-flow sampled sites.

Among the pore-water samples, the highest total concentration of domestic wastewater-indicator compounds was 

from one of the two samples from LMM. That sample had a 

total concentration of 17.2 μg/L, of which 17.15 μg/L came 

from only two compounds— 4-Cumylphenol and 4-Nonylphenol—both detergent metabolites. The other pore-water sample 

collected at that site, 1 year later, had a total concentration of 

0.13 μg/L. Of the sediment samples, the highest median total 

concentrations were from sites MRW (2,974 μg/kg) and HCW 

(2,970 μg/kg).

OWCs and Sampling Sites

OWCs were detected at all sampled streams and harbor sites. The site where the fewest number of compounds 

were detected was the harbor site OH-14, with 22 of the 69 

compounds detected at least once. The site where the most 

compounds were detected was KRM, with 59 of the 69 compounds detected at least once. 

In order to compare detected concentrations among sites, 

the detected concentrations for each sample were summed, 

using zeros for nondetections. Figure 8 shows the median sum 

concentration for each site and sample type, as well as the 

percentage of parameters detected for each site and sample 

type. The median sum concentration for base-flow samples 

was less than 5 μg/L at all sites. At the four sites where stormflow samples were collected, the median sum concentrations 

ranged from 4.4 μg/L at MRC to 40.9 μg/L at KRM. For the 

pore-water samples, the median sum concentrations ranged 

from 5.6 μg/L at UCW to 136 μg/L at HCW. The high value 

at HCW can be attributed mostly to one compound, p-Cresol, 

which was measured at 119 μg/L (estimated). P-Cresol has 

numerous applications, including in antimicrobial disinfectants, antioxidants, dyes, plastics, and pesticides. Median sum 

concentrations for sediment samples ranged from 4,889 μg/kg 

at MRC to 46,526 μg/kg at KRM.
16 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

x

x

x

o o nd nd

x

x

o x

x

x

x

x x

x

x

x

x

x

x

x

o o

oo

x

o

x

nd

1

0.1

10

100

10,000

Antioxidants (3, 2)

Dyes/pigments (1, 1)

Fire retardants (4, 4)

Plasticizers (5, 4)

Fuels (4, 4)

Solvents (2, 1)

Herbicides (7, 4)

Insecticides (6, 4)

Flavor/fragrances (10, 10)

Sterols (4, 4)

Miscellaneous (3, 1)

.01

.001

1

10

100

1,000

Total detected concentration, 

in micrograms per liter

Total detected concentration, 

in micrograms per kilogram

Antimicrobial

disinfectants (3, 3)

Detergent

metabolites (8, 8)

Human drugs,

nonprescription (3, 1)

0.1

Polycyclic aromatic

hydrocarbons (6, 6)

Base flow, n = 12

Stormflow, n = 4

Pore water, n = 9

Sediment, n = 9

nd: no detections

x

o

75th percentile

median

25th percentile

adjacent

adjacent

detached

outside

EXPLANATION

Compound class and number of compounds analyzed (water samples, sediment samples)

site to give all sites equal weight; n, number of samples)

Figure 6. Total detected class concentrations for each sample type. (Total class concentrations from each sample are averaged by 
Occurrence of Organic Waste Compounds 17

n = 0

0

0

3

0 10 12 0 0 0 11 0

n = 0

0

0

6

4 3 3 3 3 2 3 3

n = 8 8 9 9 10 9 9 9 9 9 9 9

0.02

0.05

0.1

0.2

0.5

1

2

5

10

0.01

0.05

0.1

0

1

5

10

0.1

0.2

0.5

1

2

5

10

20

10

100

1,000

10,000

Total detected concentration per sample of 20 domestic wastewater-indicator compounds

Concentration, in 

micrograms per liter

Concentration, in

micrograms per kilogram

Concentration, in 

micrograms per liter

Concentration, in 

micrograms per liter

Stormflow

Base flow

Pore water

OH-14 OH-03 MRJ MRC LMM OSM MRW UCW HCW

Stream sites (least to most urban, left to right)

RRG LCM KRM

Harbor sites

NS NS NS

NS NS NS

75th percentile

median

25th percentile

adjacent

adjacent

outside

EXPLANATION

Sediment

sanitary sewer and septic sources. (Scales differ between sample types; site abbreviations are defined in table 1; n, number of samples; 

NS, no samples collected)

Figure 7. Total detected concentration per sample of 20 domestic wastewater-indicator compounds commonly associated with 
18 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

EXPLANATION

Water

Area within the MMSD

planning area

Area outside of the 

MMSD planning area

Watershed boundary

Subwatershed boundary

Stream

Sampling site

< 40.0

40.0 - 49.9

50.0 - 59.9

60.0 - 69.9

70.0 - 79.9

Circle size:

Percent of compounds 

detected at least once

base

flow

pore

water

stormflow

sediment

Sample type:

NA Sample type not collected

Circle color: 

Sum of detected 

concentrations (median)

< 5.0

5.0 - 24.9

25.0 - 44.9

45.0 - 64.9

> 65.0

< 5,000

5,000- 16,999

17,000 - 28,999

29,000 - 40,999

> 41,000 

Water (μg/L) Sediment (μg/kg)

ROOT RIVER

MILWAUKEE RIVER

MENOMONEE

RIVER

OAK CREEK

DIRECT

TRIBUTARY

DIRECT

TRIBUTARY

LAKE

MICHIGAN

DIRECT

MRJ

Milwaukee

NA

NA

NA NA

NA NA

NA

NA

NA NA

NA

NA

NA

NA

OH-14

OH-03

OSM

HCW

LCM

UCW

KRM

LMM

RRG

MRW

MRC

88°10' 87°50'

42°50'

43°10'

Lake Michigan

WISCONSIN

MICHIGAN

ILLINOIS

IOWA

MINNESOTA

MMSD

planning area

Milwaukee

0 42 MILES

0 42 KILOMETERS

Base composited from Southeastern Wisconsin Regional Planning Commission regional base 

map, 1:2,000, 1995; U.S. Geological Survey digital line graph hydrography, 1:100,000, 1989; 

Wisconsin Department of Natural Resources version 2 hydrography, 1:24,000, 2002. Wisconsin 

Transverse Mercator Projection, referenced to North American Datum of 1983, 1991 adjustment.

planning area, Wisconsin. (Sampling site abbreviations are listed in table 1; <, less than; μg/L, micrograms per liter; μg/kg, 

micrograms per kilogram; >, greater than) 

Figure 8. Summary of the distribution of organic waste compounds in the Milwaukee Metropolitan Sewerage District (MMSD) 
Adverse Impacts on Aquatic Life 19

For most sites, the percentage of compounds detected 

at least once was lower for pore-water and sediment samples 

than for base-flow and stormflow samples. However, this 

is biased by the small number of pore-water and sediment 

samples as compared to the other sample types. For base-flow 

samples, the percentage of compounds detected at least once 

ranged from 32 percent at OH-14 to 69.6 percent at MRJ. The 

range for stormflow samples was from 44 percent at MRC to 

79.7 percent at KRM. MRC was the only stormflow sampling site where a greater percentage of the compounds were 

detected in the base-flow samples than in the stormflow samples (57 as opposed to 44 percent). As MRC is the least urban 

of the stormflow sampling sites, this indicates that storm-water 

runoff is an important source of OWCs to urban streams but 

less so to rural ones. The difference also may be related to the 

greater number of base-flow as opposed to stormflow samples 

collected at MRC (nine base-flow samples compared to six 

stormflow samples), and (or) to dilution during storm events. 

Unlike most of the other sites, MRC has several wastewatertreatment plants discharging upstream. These plants likely 

input OWCs to the stream constantly, and those inputs would 

be most concentrated during base-flow conditions. 

For pore water, the percentage of compounds detected 

at least once ranged from 28 percent at UCW to 54 percent 

at KRM. Sediment samples varied the least, ranging from 

35 percent of the compounds detected at MRC to 54 percent 

at KRM. Overall, the site with the highest OWC concentrations and detection frequencies was KRM. For both detection 

rates and median sum concentrations, KRM had the highest or 

second-highest values for each of the four sample types. MRJ, 

the stream/harbor transition site, also had high concentrations 

and detection frequencies. Though only base-flow samples 

were collected there, those samples had a higher percentage of 

compounds detected at least once, and a higher median sum 

concentration than the base-flow samples at any other site, 

including KRM. This may be in part because of MRJ’s location near the confluence of the Kinnickinnic, Menomonee, and 

Milwaukee watersheds, as well as its proximity to the Jones 

Island Water Reclamation Facility (wastewater-treatment 

plant) effluent discharge. 

More maximum compound concentrations were 

measured in samples from KRM than from any other site 

(tables 4a, 4b, 5a, and 5b). In stormflow samples, the maximum measured concentrations for 43 of the 69 compounds 

were from KRM samples; the site with the second-highest 

number of maximum compound concentrations in stormflow 

samples, OSM, had only 8. Maximum compound concentrations in pore-water and sediment samples were dominantly 

from KRM samples as well, with 18 and 16 compounds, 

respectively. Maximum compound concentrations in base-flow 

samples were more evenly distributed among sites, with MRJ, 

UCW, and KRM having the most (9, 9, and 8, respectively) 

and RRG, MRW, and MRC having the least (2, 2, and 1, 

respectively). 

The stream sites with the lowest OWC concentrations 

and detection frequencies were MRC (the least urban site) and 

UCW. For both stormflow and sediment samples, the median 

sum concentrations at MRC were approximately an order of 

magnitude less than at KRM. In the Milwaukee River Harbor, detections and concentrations decreased with increasing 

distance from the mouth of the river. Harbor site OH-14 had 

the lowest median sum concentration and the lowest percent of 

compounds detected, followed by harbor site OH-03, followed 

by the stream/harbor transition site MRJ.

Adverse Impacts on Aquatic Life

The potential impacts of OWCs on aquatic life are 

assessed by (1) discussion of EDCs, (2) comparisons of OWC 

concentrations to known toxicity benchmarks, and (3) analysis 

of toxicity bioassay results.

Endocrine-Disrupting Compounds

Of the 69 compounds sampled in this study, 27 are known 

or suspected endocrine disruptors (table 2; The Endocrine 

Disruption Exchange, Inc., 2011). Endocrine disruptors are 

compounds that possess hormone-like activity and have the 

potential to disrupt normal endocrine function by interfering 

with hormone signaling. Research has shown that exposure 

to EDCs can result in adverse reproductive, developmental, 

neurologic, immunologic, carcinogenic, and ecologic effects 

(National Research Council, 1999; Vajda and others, 2008; 

Vandenberg and others, 2012).

Known or suspected EDCs were found in all pore-water, 

stormflow, and sediment samples, and in more than 90 percent 

of base-flow samples. The median number of EDCs per sample was 8.5 for pore-water, 9 for stormflow, 4 for base-flow, 

and 6.5 for sediment samples. The maximum number of EDCs 

in a sample was 15, found in a stormflow sample from MRW. 

In base-flow samples, the highest EDC-detection rates 

were found at two of the harbor sites, OH03 and MRJ. As 

discussed in previous sections, this may be related to the 

proximity of those sites to the Jones Island Water Reclamation 

Facility (wastewater-treatment plant) effluent discharge.

OWCs and Toxicity Benchmarks

Of the 69 OWCs sampled, 25 have known AqT benchmarks (tables 4a, 4b, 5a, and 5b). These benchmarks are based 

on individual compounds, rather than the complex mixtures 

of 20 to 40 different compounds observed in environmental 

samples in this study. Likewise, benchmarks often are based 

on exposure times of 10 days or less (U.S. Environmental Protection Agency, 2002; 2003), whereas environmental exposure 

to these compounds may be measured in weeks or months. For 

these reasons, comparisons to single-compound benchmarks 

may underestimate the potential for adverse effects on aquatic 

organisms (Gilliom and others, 2006). 
20 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Figure 9 shows compounds with toxicity-benchmark 

exceedances in one or more sample type. In water samples 

(stormflow, base flow, and pore water), the compounds with 

the most frequent benchmark exceedances were PAHs: anthracene, benzo[a]pyrene, fluoranthene, phenanthrene, and pyrene. 

Benchmarks for these five PAH compounds were exceeded 

in 50 to 95 percent of all stormflow and pore-water samples, 

and in 17 to 53 percent of all base-flow samples (phenanthrene 

excluded). In stormflow and pore-water samples, the highest 

mean toxicity quotients (TQmean, computed by dividing the 

mean detected concentration by the lowest of the benchmarks) 

were for pyrene, with values of 97 and 101, respectively. This 

means that of the stormflow and pore-water samples with 

pyrene detections, the mean concentration was approximately 

100 times the AqT-benchmark value. The highest toxicity 

quotient observed also was for pyrene, in a stormflow sample 

from KRM, with a value of 1,024. The higher detection frequencies and higher mean toxicity quotients of PAHs in stormflow samples as compared to base-flow samples indicates 

urban runoff may be an important source of these compounds 

to the stream. 

Aside from the PAHs, compounds with toxicitybenchmark exceedances in water samples include DEHP 

in stormflow and base-flow samples, NP in stormflow and 

pore-water samples, and bromacil and carbaryl in base-flow 

samples (fig. 9). 

Most of the compounds with AqT exceedances in water 

samples also had exceedances in sediment samples (fig. 9). 

Benchmarks for the six PAH compounds were exceeded in 

64 to 93 percent of all sediment samples, with TQmean values 

from 3.0 to 79 in samples with detected concentrations. Other 

compounds with benchmark exceedances in sediment samples 

were DEHP (54 percent of samples, TQmean of 3.8), 2-Methylnapthalene (61 percent of samples, TQmean of 2.8), p-Cresol 

(14 percent of samples, TQmean of 0.5), phenol (46 percent 

of samples, TQmean of 4.4), and NP (29 percent of samples, 

TQmean of 0.9). 

While toxicity benchmarks for individual compounds are 

useful, aquatic organisms often are exposed to tens or hundreds of compounds at once; therefore, quantifying the toxicity of mixtures of compounds may provide a more realistic 

assessment. A number of authors have developed methods to 

compute the toxicity of mixtures of PAHs, including MacDonald and others (2000) and more recently the U.S. Environmental Protection Agency (2003; 2010). 

The EPA method computes an acute and chronic toxicitypotency factor for each sample (each mixture of PAH compounds). Acute toxicity refers to toxicity to aquatic organisms 

over a short exposure time, usually a few days or less, whereas 

chronic toxicity is over a longer exposure time. Both the acute 

and chronic potency factors use a toxicity benchmark of 1, 

where potency factors greater than 1 are considered potentially 

toxic. None of the base-flow water-column samples showed 

potential toxicity using the EPA method (fig, 10A). In contrast, 

three of the four streams sampled during stormflow conditions showed potential PAH toxicity under chronic-exposure 

conditions, and two of the four streams showed potential 

toxicity under acute-exposure conditions (fig, 10C). 

In sediment and pore-water samples, potential toxicity 

under chronic-exposure conditions was seen at seven of nine 

and four of nine sites sampled, respectively (figs. 10B and D). 

The EPA calculation for sediment requires knowledge of the 

organic content of the sample. Because that information was 

not available, a range of 1.5 to 7.0 percent organic content 

was assumed, based on the range of organic content seen in 

samples from the same and nearby streams in a previous study 

(Corsi and others, 2011). Most of the sediment samples were 

either above or below the chronic-toxicity benchmark regardless of the organic content assumed. 

For comparison to the EPA method previously described, 

probable effect concentration (PEC) quotients were computed 

for sediment samples using the method described by MacDonald and others (2000). Generally, the MacDonald and the EPA 

methods agreed on which samples were above and below the 

toxicity benchmark. 

Toxicity Bioassays 

The greatest adverse effect in samples from different 

stream compartments was observed in C. tentans assays from 

sediment samples (figs. 11, 12, and 13). Results from watercolumn sample assays indicated that C. dubia survival was 

at least 80 percent of the laboratory-control survival, and the 

mean young produced (reproduction) was at least 59 percent 

of that from the laboratory control. The three samples that had 

the lowest weights for C. dubia in water-column assay results 

were from MRC, MRM, and WCG (64, 59, and 67 percent of 

the laboratory control, respectively; fig. 11). Results from the 

OWC analysis did not indicate an obvious reason that reproduction results from these three sites should be different than 

the other sample results. MRC and MRM are the only two 

sites with wastewater-effluent discharges upstream.

Results from pore-water sample assays indicated that survival of C. dubia and H. azteca was at least 80 percent of the 

laboratory-control survival in all samples (fig. 12). The mean 

C. dubia young produced for one sample was as low as 45 percent (at site RRF), with all other sites resulting in 70 percent 

or greater of the laboratory-control results. Examination of the 

OWC pore-water sample results for site RRF did not indicate 

that concentrations were greater than samples with no adversetoxicity result. It does not appear that low C. dubia reproduction in the assay from the site RRF sample can be explained 

by concentrations of measured parameters for this study.
Adverse Impacts on Aquatic Life 21

NA NA

NA NA

Percentage of samples exceeding toxicity benchmarks

Anthracene

Benzo[a]pyrene

Fluoranthene

Phenanthrene

Pyrene

Naphthalene

Bis(2-ethylhexyl) phthalate

2-Methylnapthalene

Bromacil

Carbarylp-Cresol

Phenol

4-Nonylphenol

Compound name

0

20

40

60

80

20

40

60

80

Base-flow samples (n = 107)

Sediment samples (n = 28)

Stormflow samples (n = 39)

Pore-water samples (n = 10)

100

100

Anthracene

Benzo[a]pyrene

Fluoranthene

Phenanthrene

Pyrene

Naphthalene

2-Methylnapthalene

Bromacil

Carbarylp-Cresol

Phenol

4-Nonylphenol

Bis(2-ethylhexyl) phthalate

Mean toxicity quotient

EXPLANATION

< 1.0

1.0 - 9.9

10 - 99

≥ 100

Figure 9. Compounds with exceedances of toxicity benchmarks for one or more sample type. Bar heights indicate the percentage of 

samples exceeding the lowest benchmark listed in tables 4 and 5. Bar color indicates the maximum toxicity quotient (concentration/

benchmark) observed for each compound. Compounds in red are known or suspected endocrine disruptors according to The Endocrine 

Disruption Exchange, Inc. (2011). (n, number of samples; <, less than; ≥, greater than or equal to; 4-Nonylphenol is the sum of all isomers; 

NA, no known toxicity benchmark)
22 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9 assuming 1.5 percent organic content assuming 7.0 percent organic content

EXPLANATION

chronictoxicity abovebenchmark

MRC

10

1

0.1

0.01

KRM

6 6

MRW

12 12 11 11

OSM

10 10

AcuteChronic

n =

Potency factor for PAH mixture (six compounds)

Stream sites (least to most urban, left to right)

toxic abovebenchmark

Harbor sites

MRC LMM MRW RRG LCM MRJ OH-03 OH-14 HCW KRM OSM

o x

o

UCW

x

o

9 9 10 10 99 9 9 999 9 9 9 9 9 9 9 8 8 9 9 8 8 n =

Potency factor for PAH mixture (six compounds)

Stream sites (least to most urban, left to right)

toxic abovebenchmark

MRC MRW RRG LCM LMM UCW HCW KRM OSM

Stream sites (least to most urban, left to right)

toxic abovebenchmark

A. Stormflow

C. Base flow

B. Sediment EXPLANATION

100

10

1

0.1

0.01

0.001

0.1

0.01

1

MRC LMM MRW KRM OSM RRG LCM

AcuteChronic

HCW UCW

toxic abovebenchmark

Stream sites (least to most urban, left to right)

D. Pore water

10

100 1.2

1.00.80.60.40.20.0

EXPLANATION

AcuteChronic

o

x

detachedoutsideadjacent75th percentilemedian25th percentileadjacent

EXPLANATION

Figure 10. Polycyclic aromatic hydrocarbons toxicity. 

A, Stormflow samples. 

B, Sediment samples. 

C, Base-flow samples. 

D, Pore-water samples. A sample with a potency 

factor greater than 1 is considered toxic, based on calculations developed by the U.S. Environmental Protection Agency (2010). Acute and chronic toxicity were calculated for was used because the actual organic content was not known. (Site abbreviations are defined in table 1; PAH, polycyclic aromatic hydrocarbon; n, number of samples)each sample, using different computations (only chronic toxicity is shown for sediment samples). For the sediment-sample calculations, an expected range of organic content 
Adverse Impacts on Aquatic Life 23

0

20

40

60

80

100

120

0

20

40

60

80

100

120

PCD

MRC

MRM

WCG

MMFLMM

OSM

MRW

RRF

UCW

RRG

LCM

KRM

HCW

Percent of control

Ceriodaphnia dubia Reproduction

Ceriodaphnia dubia Survival

Sample site (least to most urban, left to right)

Figure 11. Water-column bioassay results for 14 sites in the 

Milwaukee area, 2006–7. Error bars indicate the standard error 

of replicates for each result. (Site abbreviations are defined 

in table 1.)

Survival observed in sediment assay results for C. tentans

was as low as 15 percent of that from the laboratory control 

at site LCM, but survival was 62 percent or greater of the 

laboratory control for all other samples (fig. 13). Weight of C. 

tentans was as low as 11 percent of the laboratory control for 

site LCM. Survival of H. azteca was at least 70 percent and 

weight was at least 97 percent of the laboratory control for 

all samples. Results for survival of both organisms were not 

substantially different after UV treatment (fig. 13). 

C. tentans weights were analyzed with respect to OWCanalysis results as an attempt to explain adverse effect as 

defined in the section “Toxicity in Stream Compartments.” 

Correlation coefficients of C. tentans weight to rank summations were all negative, indicating a clear increase of toxicity as OWC contamination increased in sediment samples 

(table 6). Scatter plots of the rank sums and C. tentans weight 

showed that three sites (HCW, LMM, and LCM) were persistent outliers in this relation. Less toxicity was observed 

in the samples from HCW and LMM than would have been 

Figure 12. Pore-water assay results for 14 sites in the 

0

50

100

150

20

40

60

80

100

120

0

20

40

60

80

100

120

PCD

MRC

MRM

WCG

MMFLMM

OSM

MRW

RRF

UCW

RRG

LCM

KRM

HCW

Ceriodaphnia dubia Reproduction

Ceriodaphnia dubia Survival

Hyallela azteca Survival 

Percent of control

Sample site (least to most urban, left to right)

Milwaukee area, 2006–7. Error bars indicate the standard error 

of replicates for each result. (Site abbreviations are defined in 

table 1.)

predicted by any of the rank summations. More toxicity was 

observed in the LCM sample than would have been predicted 

by rank summations. This is not unexpected for the LCM 

sample since it was collected at a different time than the bioassay sample owing to laboratory complications. It is uncertain 

why the data from HCW and LMM appear different than other 

sites. Correlation coefficients computed without these outliers 
24 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

0

20

40

60

80

100

120

NSNS

0

20

40

60

80

100

120

140

0

20

40

60

80

100

120

NSNS

0

50

150

200

NSNSNSNSNSNSNSNSNSNSNSNSNSNS

PCD

MRC

MRM

WCG

MMFLMM

OSM

MRW

RRF

UCW

RRG

LCM

KRM

HCW

Chironomus tentans Survival 

Chironomus tentans Weight 

Hyallela azteca Survival 

Hyallela azteca Weight 

Percent of control

Pre-UV light treatment

Post-UV light treatment

NSNSNSNSNSNSNSNSNSNSNSNSNSNS

Sample site (least to most urban, left to right)

100

Figure 13. Sediment assay results for 14 sites in the Milwaukee 

area, 2006–7. Error bars indicate the standard error of replicates 

for each result. (Site abbreviations are defined in table 1; UV, 

ultraviolet; NS, not sampled)

improved for all except three of the class combinations. The 

classes that produced the best correlation (r = −0.97) of rank 

summations to C. tentans weight without outliers were PAHs, 

solvents, and fire retardants (fig. 14, table 6). The classes that 

produced the best correlation (r = −0.74) of rank summations 

to C. tentans weight using all sites including outliers were 

fuels, solvents, and fire retardants. 

Most of the top 10 correlation coefficients using all sites 

or with the 2 outliers removed included PAHs, fuels, or both 

as categories. Other common variables included for the top 10 

correlation coefficients were detergent metabolites, solvents, 

and fire retardants. Solvents and fire retardants were detected 

at only one site each (PCD and LMM, respectively), but inclusion of these two classes substantially improved explanation 

of C. tentans weight in sediment-assay variability (correlation 

coefficient closer to 1.0).

This comparison of OWC-category rankings with sediment bioassay results indicates a strong correlation between 

sediment toxicity and OWC presence. PAHs explain much of 

the variability in this relation and often were shown to exceed 

toxicity benchmarks in the potency-factor assessment for 

PAHs, so it is reasonable to assume that PAHs play a role in 

the observed toxicity. Still, there are strong cross-correlations 

between PAHs with fuels and insecticides (r = 0.79 and 0.95 

for concentrations and r = 0.91 and 0.94 for ranks, respectively). This indicates a possibility that there could be influence from other OWCs or that the adverse effects observed 

could be owing to a mixture of these OWCs.

PNL

MRC

LCM

MRM

WCG

MMF

LMM

UCW

HCW

MRW

KRMOSM

RRG

RRF

16 18 20 22 24 26 28

20

40

60

80

100

120

Median regression

EXPLANATION

Chironomus tentans

Summation of rankings

 weight as percent of laboratory control

Figure 14. Relation between Chironomus tentans weight and 

rank summations of concentrations of polycyclic aromatic 

hydrocarbons, solvents, and fire retardants in sediment samples. 

(Site abbreviations are defined in table 1.)
Adverse Impacts on Aquatic Life 25

Table 6. Pearson correlation coefficients of Chironomus tentans weight to rank summations of concentrations of classes of organic 

waste compounds in sediment samples, southeast Wisconsin, 2006–9.

[OWC, organic waste compound; HCW, Honey Creek at Wauwatosa; LMM, Little Menomonee River at Milwaukee; LCM, Lincoln Creek 47th Street at 

Milwaukee; PAH, polycyclic aromatic hydrocarbon; top ten correlation coefficients are shown in bold]

OWC classes included

Pearson correlation coefficients of 

Chironomus tentans

All sites

Sites without 

persistent outliers 

(HCW, LMM, and LCM)

Detergent metabolites

−0.49 −0.81

Fire retardant −.55 −.86

Fuel −.61 −.82

Insecticide −.49 −.82

PAH −.53 −.82

Solvent −.5 −.82

Fire retardant Fuel −.66 −.89

Fire retardant Insecticide −.54 −.88

Fire retardant PAH −.58 −.88

Fire retardant Solvent −.56 −.88

Fuel Insecticide −.55 −.81

Fuel PAH −.57 −.82

Fuel Solvent −.64 −.86

Insecticide PAH −.5 −.82

Insecticide Solvent −.52 −.86

PAH Solvent −.57 −.88

Fire retardant

−.32 −.42

Fuel −.69 −.88

Insecticide −.53 −.87

PAH −.56 −.86

Solvent −.26 −.33

Fuel Insecticide −.59 −.85

Fuel PAH −.61 −.86

Fuel Solvent −.74 −.92

Insecticide PAH −.52 −.85

Insecticide Solvent −.58 −.95

PAH Solvent −.64 −.97

Fuel

−.59 −.75

Insecticide −.52 −.77

PAH −.54 −.78

Solvent −.62 −.78

Insecticide PAH −.51 −.78

Insecticide Solvent −.56 −.82

PAH Solvent −.58 −.84

Insecticide

−.43 −.77

PAH −.45 −.78

Solvent −.47 −.84

PAH Solvent −.5 −.85

PAH

−.47 −.77

Solvent −.54 −.87

Solvent −.03 −.02
26 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Summary and Conclusions

During 2006–9, the U.S. Geological Survey, in cooperation with the Milwaukee Metropolitan Sewerage District, sampled a suite of 69 organic waste compounds (OWCs) in different stream compartments and flow regimes in Milwaukee area 

streams and in the Milwaukee Harbor. Three stream compartments were represented: water column, streambed pore water, 

and streambed sediment. Water-column samples were divided 

by flow regime into surface water during base-flow conditions 

and surface water during stormflow conditions. OWC data 

should be interpreted cautiously as laboratory recovery rates 

vary (see Quality Assurance/Quality Control section).

OWCs were detected in all 196 samples collected, with as 

many as 41 different compounds detected in a single sample. 

Of the 69 compounds analyzed, 64 were detected at least once. 

The lowest detection rates were in the base-flow samples, 

with a median of 12 compounds detected per sample. Median 

detection rates for stormflow, streambed pore-water, and 

streambed-sediment samples were approximately double those 

of the base-flow samples. The compound classes with the 

highest detection rates were the polycyclic aromatic hydrocarbons (PAHs), insecticides, herbicides, and dyes/pigments. 

The compound classes with the highest detected concentrations were the PAHs (water and sediment samples) and the 

herbicides (water samples only). Sterols also had relatively 

high detection frequencies and concentrations in both water 

and sediment samples, but some of those compounds are 

naturally occurring and not necessarily human-derived. The 

PAH concentrations show a clear urban gradient in stormflow 

samples, with concentrations increasing with increasing urban 

area. However, the urban gradient is less clear in base-flow 

PAH concentrations, indicating that urban runoff is an important source of PAHs to the streams. Total concentrations of 

the 20 domestic wastewater-indicator compounds also show 

an urban gradient in stormflow samples, indicating increased 

sanitary and (or) septic system leaks or releases during stormflow conditions, as compared to base flow. 

The Kinnickinnic River (KRM)—one of the most urban 

sites—had some of the highest detection frequencies and 

concentrations in all sample types. Sites with the lowest 

detection frequencies and concentrations were the least urban 

stream sites: Milwaukee River near Cedarburg (MRC), and 

Middle Outside Harbor Breakwater Lake Site (OH-14). The 

Milwaukee River at the mouth at Jones Island (MRJ) site had 

some of the highest detection frequencies and concentrations 

of endocrine-disrupting chemicals and domestic wastewaterindicator compounds, likely in part because of its proximity 

to the Jones Island Water Reclamation Facility (wastewatertreatment plant) effluent discharge point. 

Aquatic-toxicity benchmarks were exceeded for 12 of 

the 25 compounds with known benchmarks. The compounds 

with the greatest benchmark exceedances were the PAHs, 

both in terms of exceedance frequency (up to 93 percent 

for some compounds in sediment samples) and magnitude 

(concentrations up to 1,024 times greater than the benchmark 

value). Other compounds with toxicity-benchmark exceedances include Bis(2-ethylhexyl) phthalate (a plasticizer), 

2-Methylnapthalene (a component of fuel and oil), phenol (an 

antimicrobial disinfectant with diverse uses), and 4-Nonylphenol (sum of all isomers; a detergent metabolite, among other 

uses). Analyzed as a mixture, the suite of PAH compounds 

were found to be potentially toxic in stormflow samples from 

three of four sites, in pore-water samples from four of nine 

sites, and in sediment samples from seven of nine sites. Baseflow samples showed low potential for PAH toxicity when 

those compounds were analyzed as a mixture. These results 

indicate that the likely source of PAHs to the stream is urban 

nonpoint runoff during storm events, and that the PAHs then 

collect in the streambed sediments. 

Bioassay tests were conducted on base-flow samples, 

pore-water samples, and sediment samples, with the greatest 

adverse effect in Chironomus tentans assays from sediment 

samples. The sediment bioassay results were highly correlated 

with OWC results. There was a relation between PAH results 

and bioassay results for the majority of samples; however, 

solvents and flame retardants appeared to be important for one 

site each as well. 

From an aquatic toxicity standpoint, PAHs are prominent 

in this study as compounds that likely have an adverse effect 

on aquatic organisms. This is evident from evaluation of the 

computed potency factors as well as results from direct bioassay testing. Additional insight on impacts to aquatic organisms 

may be gained if more aquatic-life criteria were available 

to help evaluate these data. In addition, if longer duration, 

chronic-toxicity information were made available, it may be 

valuable to perform a long-term assessment of the impacts of 

these compounds on aquatic life.

Acknowledgments

Technical Reviewers

Patrick Phillips, U.S. Geological Survey New York 

Water Science Center, Troy, N.Y.

Donald Wilkison, U.S. Geological Survey Missouri 

Water Science Center, Lee’s Summit, Mo.

Editorial Reviewer

Bonnie J. Stich, Editor, U.S. Geological Survey Science Publishing Network, Louisville, Ky.

Graphics

Jennifer Bruce, U.S. Geological Survey Wisconsin 

Water Science Center, Middleton, Wis.

Michelle Lutz, U.S. Geological Survey Wisconsin 

Water Science Center, Middleton, Wis.
References Cited 27

Data Collection

David Graczyk, U.S. Geological Survey Wisconsin 

Water Science Center, Middleton, Wis.

Eric Waldmer, Milwaukee Metropolitan Sewerage 

District, Milwaukee, Wis.

Susan Sutherland, Milwaukee Metropolitan Sewerage District, Milwaukee, Wis.

Meredith Welling, Milwaukee Metropolitan Sewerage District, Milwaukee, Wis.

Mark Munzenmaier, Milwaukee Metropolitan Sewerage District, Milwaukee, Wis.

Ken Wardius, Milwaukee Metropolitan Sewerage 

District, Milwaukee, Wis.

Jean Bourne, Milwaukee Metropolitan Sewerage 

District, Milwaukee, Wis.

Approving Official

Kevin Breen, Bureau Approving Official, U.S. 

Geological Survey Office of Science Quality and 

Integrity, New Cumberland, Pa.

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30 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9 Table 2. Organic waste compounds sampled, their classes, and possible uses, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; CAS, Chemical Abstracts Service; μg/L, micrograms per liter; μg/kg, micrograms per kilogram; na, not analyzed; PAH, polycyclic aromatic hydrocarbons; >, greater than; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] OWC class Compound name CAS registry number Reporting level Possible compound uses or sources† Water samples (μg/L) Sediment samples (μg/kg)‡ Antioxidants 3-tert-Butyl-4-hydroxyanisole (BHA) 25013-16-5 0.2 150 Antioxidant, general preservative 5-Methyl-1H-benzotriazole 136-85-6 1.22, 1.6, 2.0 na Antioxidant in antifreeze and deicers Bisphenol A 80-05-7 0.4, 1.0 50 Manufacturing polycarbonate resins, antioxidant, flame retardant Dyes/ pigments 9, 10-Anthraquinone 84-65-1 0.2, 0.5 50 Manufacturing dye/textiles, seed treatment, bird repellant Fire retardants BDE congener 47 (tetrabromodiphenyl ether)* 5436-43-1 0.2, 0.3, 0.39, 0.5 50 Flame retardant Tributyl phosphate* 126-73-8 0.2, 0.5 50 Antifoaming agent, flame retardant Tris(2-butoxyethyl) phosphate* 78-51-3 0.2, 0.21, 0.22, 0.26, 0.28, 0.3, 0.49, 0.5, 0.54, 150 Flame retardant Tris(dichloroisopropyl) phosphate (Fyrol FR 2)* 13674-87-8 0.2, 0.5 100 Flame retardant PAH Anthracene 120-12-7 0.2, 0.5 50 Wood preservative, component of tar, diesel, crude oil, combustion product Benzo[a]pyrene 50-32-8 0.2 50 Regulated PAH, used in cancer research, combustion product Fluoranthene 206-44-0 0.2, 0.3 50 Component of coal tar and asphalt (only traces in gasoline or diesel fuel), combustion product Naphthalene 91-20-3 0.2 50 Fumigant, moth repellent, major component (about 10 percent) of gasoline Phenanthrene 85-01-8 0.2 50 Manufacturing explosives, component of tar, diesel fuel, or crude oil, combustion product

Pyrene 129-00-0 0.2, 0.4 50 Component of coal tar and asphalt (only traces in gasoline or diesel fuel), combustion product
Table 2 31

Table 2. Organic waste compounds sampled, their classes, and possible uses, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; CAS, Chemical Abstracts Service; μg/L, micrograms per liter; μg/kg, micrograms per kilogram; na, not analyzed; PAH, polycyclic aromatic hydrocarbons; >, greater than; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] 

Reporting level

CAS OWC Water Sediment Compound name registry Possible compound uses or sources† class samples samples number

(μg/L) (μg/kg)‡

Plasticizer for polymers and resins; major Bis(2-ethylhexyl) phthalate (DEHP) 117-81-7 0.22, 2.0, 2.1, 2.62, 9.8 250 component of vinyl

Makes plastics more flexible; also cosmetics, Diethyl phthalate 84-66-2 0.2, 0.22, 0.26, 0.32, 0.39, 0.5 100 insecticides, aspirin

Plasticizers Triethyl citrate 77-93-0 0.2, 0.5 na Cosmetics, pharmaceuticals 

Plasticizer, resin, wax, finish, roofing paper, Triphenyl phosphate 115-86-6 0.2, 0.5 50 flame retardant

Tris(2-chloroethyl) phosphate (Fyrol CEF) 115-96-8 0.2, 0.5 100 Plasticizer, flame retardant 

1-Methylnaphthalene 90-12-0 0.2, 0.5 50 2-5 percent of gasoline, diesel fuel, or crude oil 

2,6-Dimethylnaphthalene 581-42-0 0.2, 0.5 50 Present in diesel/kerosene (trace in gasoline) 

Fuels

2-Methylnaphthalene 91-57-6 0.2, 0.5 50 2-5 percent of gasoline, diesel fuel, or crude oil 

Manufacturing phenol/acetone, fuels and paint Isopropylbenzene (cumene) 98-82-8 0.2, 0.5 100 thinner 

Isophorone 78-59-1 0.2, 0.5 50 Solvent for lacquer, plastic, oil, silicon, resin 

Solvents

Tetrachloroethene (PERC) 127-18-4 0.4, 0.5 na Solvent, degreaser, veterinary anthelmintic 
32 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9 Table 2. Organic waste compounds sampled, their classes, and possible uses, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; CAS, Chemical Abstracts Service; μg/L, micrograms per liter; μg/kg, micrograms per kilogram; na, not analyzed; PAH, polycyclic aromatic hydrocarbons; >, greater than; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] Reporting level CAS OWC Water Sediment Compound name registry Possible compound uses or sources† class samples samples number (μg/L) (μg/kg)‡ Herbicide, selective for weed control and used Atrazine 1912-24-9 0.2 100 on cropland and highway and railroad rights of way Herbicide (general use pesticide), >80 percent Bromacil 314-40-9 0.2, 0.26, 0.5, 0.8 500 non-crop usage on grass/brush Dichlorophenyl isocyanate 102-36-3 0.5, 1.6, 2.0 na Degradate of diuron, a non-crop herbicide Herbicide, fungicide (general use pesticide), Herbicides Metalaxyl 57837-19-1 0.2, 0.5 na mildew, blight, pathogens, golf/turf Herbicide (general use pesticide), indicator of Metolachlor 51218-45-2 0.2, 0.5 50 agricultural drainage Herbicide, fungicide, wood preservative, Pentachlorophenol (PCP) 87-86-5 0.8, 1.6, 1.71, 2.0, 3.2 na termite control Herbicide (noncrop only), applied prior to b Prometon 1610-18-0 0.2, 0.5, 1.6 50 lacktop Carbaryl 63-25-2 0.2, 1.0 na Insecticide, crop and garden uses, low persistence Insecticide, Manufacturing dyes, explosives, Carbazole 86-74-8 0.2, 0.5 50 and lubricants Insecticide, domestic pest and termite control Chlorpyrifos 2921-88-2 0.2, 0.5 50 (domestic use restricted as of 2001) Insecticides Insecticide, >40 percent nonagricultural usage, Diazinon 333-41-5 0.2, 0.5 50 ants, flies Insecticide, control of parasites on livestock Dichlorvos 62-73-7 0.2, 1.0 na and pets (pet collars) N, N-diethyl-meta-toluamide (DEET) 134-62-3 0.2, 0.25 100 Insecticide, urban uses, mosquito repellent 

Wood preservative, dissolve other chemicals, p-Cresol (para-Cresol) 106-44-5 0.2, 1.0 250 disinfectant

Antimicrobial Disinfectant, slimicide, manufacturing of synthetic Phenol 108-95-2 0.2, 0.5 50 disinfectants fibers, mouthwash

Disinfectant, antimicrobial (concern for acquired Triclosan* 3380-34-5 0.2, 1.0 50 microbial resistance) 
Table 2 33

Table 2. Organic waste compounds sampled, their classes, and possible uses, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; CAS, Chemical Abstracts Service; μg/L, micrograms per liter; μg/kg, micrograms per kilogram; na, not analyzed; PAH, polycyclic aromatic hydrocarbons; >, greater than; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] 

Reporting level

CAS OWC Water Sediment Compound name registry Possible compound uses or sources† class samples samples number

(μg/L) (μg/kg)‡

 4-tert-Octylphenol monoethoxylate* NA 1 250 Nonionic detergent metabolite 4-Cumylphenol* 599-64-4 0.2, 1.0 50 Nonionic detergent metabolite 

4-Nonylphenol (sum of all isomers)* 84852-15-3 1.6, 5.0 750 Nonionic detergent metabolite 4-Nonylphenol diethoxylate* 20427-84-3 3.2, 5.0 1,000 Nonionic detergent metabolite Detergent 

metabolites

4-Nonylphenol monoethoxylate* 104-35-8 1.6, 2.0 500 Nonionic detergent metabolite 

4-Octylphenol (4-normal-Octylphenol)* 1806-26-4 0.2, 1.0 50 Nonionic detergent metabolite 4-tert-Octylphenol diethoxylate* NA 0.32, 0.5, 1.0 50 Nonionic detergent metabolite 

4-tert-Octylphenol* 140-66-9 0.2, 0.4, 1.0 50 Nonionic detergent metabolite 
34 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9 Table 2. Organic waste compounds sampled, their classes, and possible uses, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; CAS, Chemical Abstracts Service; μg/L, micrograms per liter; μg/kg, micrograms per kilogram; na, not analyzed; PAH, polycyclic aromatic hydrocarbons; >, greater than; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] Reporting level CAS OWC Water Sediment Compound name registry Possible compound uses or sources† class samples samples number (μg/L) (μg/kg)‡ 3-Methyl-1H-indole (skatol) 83-34-1 0.2, 1.0 50 Fragrance, stench in feces and coal tar Fragrance in detergent and tobacco, flavor in Acetophenone 98-86-2 0.2, 0.3, 0.32, 0.37, 0.4, 0.5 150 beverages Acetyl hexamethyl tetrahydro naphthalene Musk fragrance (widespread usage), persistent 21145-77-7 0.2, 0.5 50 (AHTN)* in groundwater Benzophenone* 119-61-9 0.2, 0.4, 0.5 50 Fixative for perfumes and soaps Camphor* 76-22-2 0.2, 0.5 50 Flavor, odorant, ointments Flavors and fragrances Citrus flavoring and fragrance in food and houshold 

d-Limonene* 5989-27-5 0.2, 0.5 50 products, fungicide, antimicrobial, antiviral

Hexahydrohexamethyl cyclopentabenzopy- Musk fragrance (widespread usage) persistent 1222-05-5 0.2, 0.5 50 ran (HHCB)* in ground water 

Indole 120-72-9 0.2, 0.5 100 Pesticide inert ingredient, fragrance in coffee Isoborneol* 124-76-5 0.2, 0.5 50 Fragrance in perfumery and disinfectants 

Isoquinoline* 119-65-3 0.2, 0.5 100 Flavors and fragrances 

Stimulant, beverages, diuretic, very mobile/ Caffeine 58-08-2 0.2, 0.5 na biodegradable 

Human drugs, nonpre- Cotinine 486-56-6 0.8, 1.0 na Primary nicotine metabolite 

scription

Menthol 89-78-1 0.2, 0.29, 0.32, 0.4, 0.5 50 Cigarettes, cough drops, liniment, mouthwash 
Table 2 35

Table 2. Organic waste compounds sampled, their classes, and possible uses, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; CAS, Chemical Abstracts Service; μg/L, micrograms per liter; μg/kg, micrograms per kilogram; na, not analyzed; PAH, polycyclic aromatic hydrocarbons; >, greater than; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] 

Reporting level

CAS OWC Water Sediment Compound name registry Possible compound uses or sources† class samples samples number

(μg/L) (μg/kg)‡

3-beta-Coprostanol 360-68-9 0.8, 1.2, 1.5, 1.6, 2.0 500 Carnivore fecal indicator 

beta-Sitosterol 83-46-5 0.8, 1.5, 1.6, 2.0, 2.09, 2.15, 3.2 500 Plant sterol 

Sterols

beta-Stigmastanol 19466-47-8 0.8, 0.94, 1.05, 1.3, 1.6, 1.7, 2.0, 2.4 500 Plant sterol, pulp-mill waste, decomposing paperCholesterol 57-88-5 0.8, 0.85, 0.91, 1.08, 1.1, 1.4, 1.6, 2.5 250 Often a fecal indicator, also a plant sterol 1,4-Dichlorobenzene 106-46-7 0.2, 0.5 50 Moth repellant, fumigant, deodorant 

Miscella- Methyl salicylate 119-36-8 0.2, 0.45, 0.5 na Liniment, food, beverage, UV-absorbing lotion neous

Wastewater ozination byproduct, military/ Tribromomethane (bromoform) 75-25-2 0.2, 0.5 na explosives 

‡ Reporting levels of sediment samples were variously elevated because of interferences.† Zaugg and others, 2007.* Compounds considered by the authors to be domestic wastewater-indicator compounds likely from sanitary sewer sources.
36 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9 Table 4a. Organic waste compounds sampled and summary of analytical results of water samples, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; μg/L, micrograms per liter; ND, not detected; e, estimated; PAH, polycyclic aromatic hydrocarbon; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] OWC class Compound name Detection frequencies (percent) Median detected concentration (μg/L)‡ Maximum detected concentration (μg/L), and site* Base flow Storm- flow Pore water Base flow Storm- flow Pore water Base flow Stormflow Pore water Antioxidants 3-tert-Butyl-4-hydroxyanisole (BHA) 0 0 0 ND ND ND ND ND ND 5-Methyl-1H- benzotriazole 32 33 40 e0.239 e1.25 e0.278 5.36, KRM e3.42, KRM e0.379, LCM Bisphenol A 24 77 100 e0.063 e0.144 e0.269 e0.311, LCM e1.12, KRM 1.47, LMM Dyes/pigments 9,10-Anthraquinone 46 95 100 e0.091 0.45 e0.30 0.416, LCM e2.98, KRM 2.13, KRM Fire retardants BDE congener 47 (tetrabromodiphenyl ether)** 0 0 0 ND ND ND ND ND ND Tributyl phosphate** 32 74 50 e0.0539 0.35 e0.0414 4.2, KRM e4.69, KRM e0.144, KRM Tris(2-butoxyethyl) phosphate** 50 64 60 e0.268 e0.389 e0.982 13.4, RRG e1.5, KRM e1.3, UCW Tris(dichloroisopropyl) phosphate (Fyrol FR 2)** 30 49 60 e0.0612 e0.0784 e0.0462 0.268, UCW 0.23, KRM e0.0642, LCM PAHs Anthracene 25 74 90 e0.0142 e0.118 e0.182 e0.0556, UCW 5.16, KRM 1.0, KRM Benzo[a]pyrene 23 95 100 e0.0447 0.42 0.40 e0.14, UCW e8.88, KRM 7.23, KRM Fluoranthene 76 100 90 e0.061 e0.927 e1.2 0.651, UCW e25.6, KRM 11.6, KRM Naphthalene 9 67 70 e0.0281 e0.0707 e0.0871 e0.14, OH-14 0.26, KRM e0.187, RRG Phenanthrene 51 100 90 e0.0382 e0.519 e0.551 0.343, UCW e26.3, KRM 6.59, KRM

Pyrene 71 100 90 e0.0479 e0.705 e0.927 0.413, UCW e25.6, KRM 10.1, KRM
Table 4a 37

Table 4a. Organic waste compounds sampled and summary of analytical results of water samples, southeast Wisconsin, 2006–9.—Continued[OWC, organic waste compound; μg/L, micrograms per liter; ND, not detected; e, estimated; PAH, polycyclic aromatic hydrocarbon; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)]

Detection Median detected Maximum detected 

frequencies concentration concentration 

OWC class Compound name (percent) (μg/L)‡ (μg/L), and site*

Base Storm- Pore Base Storm- Pore Base flow Stormflow Pore water flow flow water flow flow water

Bis(2-ethylhexyl) phthalate 2 23 0 e0.248 e1.33 ND e0.309, OH-14 2.4, KRM ND (DEHP)

Diethyl phthalate 5 26 0 0.21 e0.251 ND 0.3, OH-03 0.46, MRW ND

Plasticizers Triethyl citrate 15 15 0 e0.0326 e0.0546 ND e0.151, MRJ 0.282, MRW ND

Triphenyl phosphate 24 44 30 e0.0246 e0.0431 e0.0198 e0.0555, HCW e0.116, KRM e0.0481, HCWTris(2-chloroethyl) phosphate 42 90 90 e0.0522 e0.125 e0.0492 0.87, HCW 0.418, OSM e0.0787, OSM (Fyrol CEF)1-Methylnaphthalene 18 59 60 e0.0101 e0.0312 e0.0389 e0.132, OH-14 0.349, KRM e0.0794, KRM2,6-Dimethylnaphthalene 20 54 100 e0.01 e0.0232 e0.0159 e0.159, OH-14 0.379, KRM e0.0733, KRM

Fuels

2-Methylnaphthalene 16 62 60 e0.0132 e0.0378 e0.0322 e0.184, OH-14 0.377, KRM e0.105, KRMIsopropylbenzene (cumene) 0 3 0 ND e0.0081 ND ND e0.0081, KRM ND

Isophorone 22 100 60 e0.0127 e1.42 e0.0331 e0.0386, MRW e18.2, OSM e0.0613, HCW

Solvents

Tetrachloroethene (PERC) 22 18 40 e0.0082 e0.0095 e0.0078 e0.0281, LCM e0.0169, MRW e0.0116, KRMAtrazine 69 46 90 e0.0472 e0.123 e0.0358 0.795, OH-03 1.4, MRC e0.447, LMMBromacil 16 28 30 e0.212 e0.163 0.62 e6.2, LMM e0.379, KRM e2.62, LMM

Herbicides

Dichlorophenyl isocyanate 64 67 90 e0.190 e0.28 e7.51 e115, LMM e14.7, MRW e24.3, LMMMetalaxyl 0 0 10 ND ND e0.061 ND ND e0.061, RRG
38 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9 Table 4a. Organic waste compounds sampled and summary of analytical results of water samples, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; μg/L, micrograms per liter; ND, not detected; e, estimated; PAH, polycyclic aromatic hydrocarbon; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] Detection Median detected Maximum detected frequencies concentration concentration OWC class Compound name (percent) (μg/L)‡ (μg/L), and site* Base Storm- Pore Base Storm- Pore Base flow Stormflow Pore water flow flow water flow flow water Metolachlor 38 46 40 e0.0206 e0.0277 e0.0583 0.706, OH-03 1.38, MRC e0.242, LMM Herbicides Pentachlorophenol (PCP) 25 77 40 e0.726 e0.457 e0.0666 e3.01, LCM e3.26, KRM e0.0796, KRM Prometon 16 15 50 e0.0306 e0.0496 e0.0204 e0.0495, OSM e0.0792, KRM e0.0409, OSM Carbaryl 3 18 0 e0.0989 e0.0804 ND e0.225, UCW e0.109, MRW ND Carbazole 30 87 100 e0.0208 e0.139 e0.177 e0.0973, UCW 1.56, KRM 1.36, RRG Chlorpyrifos 0 3 0 ND e0.018 ND ND e0.018, OSM ND Insecticides Diazinon 0 0 0 ND ND ND ND ND ND Dichlorvos 2 3 0 e0.117 e0.0245 ND e0.216, RRG e0.0245, OSM ND N, N-diethyl-meta-toluamide e0.165, OSM, 58 82 90 e0.0538 e0.0996 e0.105 0.293, OSM e0.776, KRM (DEET) RRG p-Cresol (para-Cresol) 16 33 50 e0.0481 e0.0668 e0.196 0.272, KRM 0.245, KRM e119, HCW Antimicrobial Phenol 10 31 30 0.26 e0.162 e0.171 0.511, OH-14 0.549, KRM 6.33, HCW disinfectants Triclosan** 12 3 0 e0.0557 e0.0672 ND e0.162, LMM e0.0672, MRC ND 4-tert-Octylphenol 2 10 0 e0.411 e0.664 ND e0.421, KRM e1.0, KRM ND monoethoxylate**

Detergent metabolites 4-Cumylphenol** 8 46 60 e0.0299 e0.0559 e0.0959 e0.0436, OSM 0.569, KRM 4.65, LMM

4-Nonylphenol 22 74 70 e0.195 e0.71 e0.396 e0.442, MRJ e3.81, KRM e12.5, LMM (sum of all isomers)**
Table 4a 39

Table 4a. Organic waste compounds sampled and summary of analytical results of water samples, southeast Wisconsin, 2006–9.—Continued[OWC, organic waste compound; μg/L, micrograms per liter; ND, not detected; e, estimated; PAH, polycyclic aromatic hydrocarbon; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)]

Detection Median detected Maximum detected 

frequencies concentration concentration 

OWC class Compound name (percent) (μg/L)‡ (μg/L), and site*

Base Storm- Pore Base Storm- Pore Base flow Stormflow Pore water flow flow water flow flow water

4-Nonylphenol diethoxylate** 5 10 30 e1.9 e1.06 e0.662 e3.03, MRJ e1.96, KRM e0.749, KRM4-Nonylphenol 10 0 0 e0.291 ND ND e0.568, MRJ ND ND monoethoxylate**

4-Octylphenol Detergent metabolites 0 0 0 ND ND ND ND ND ND (4-normal-Octylphenol)**

4-tert-Octylphenol diethoxylate** 3 21 0 e0.496 e0.426 ND e0.779, KRM e1.77, KRM ND4-tert-Octylphenol** 1 5 0 e0.032 e0.0454 ND e0.032, OH-03 e0.0587, KRM ND3-Methyl-1H-indole (skatol) 3 8 60 e0.0055 e0.0071 e0.0354 e0.0115, OSM e0.0072, KRM 1.5, HCWAcetophenone 1 5 0 e0.0382 0.40 ND e0.0382, KRM 0.482, KRM NDAcetyl hexamethyl tetrahydro 7 0 0 e0.0203 ND ND e0.0605, MRJ ND ND naphthalene (AHTN)**Benzophenone** 7 31 50 e0.0769 e0.0566 e0.0565 e0.116, MRJ e0.0937, OSM e0.0781, MRCCamphor** 15 49 100 e0.0413 e0.0773 e0.0596 0.266, LCM e0.171, KRM 0.575, RRG

Flavors and fragrances

d-Limonene** 1 3 20 e0.131 e0.141 e0.0664 e0.131, UCW e0.141, KRM e0.0812, KRMHexahydrohexamethyl 31 13 30 e0.0615 e0.0244 e0.0254 0.54, MRJ e0.0444, MRC e0.0292, KRM cyclopentabenzopyran (HHCB)**Indole 10 10 30 e0.0091 e0.0337 0.99 e0.018, KRM e0.06, KRM 1.02, MRCIsoborneol** 0 0 0 ND ND ND ND ND NDIsoquinoline** 0 3 13 ND e0.095 e0.0689 ND e0.095, KRM e0.0689, RRG
40 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9 Table 4a. Organic waste compounds sampled and summary of analytical results of water samples, southeast Wisconsin, 2006–9.—Continued [OWC, organic waste compound; μg/L, micrograms per liter; ND, not detected; e, estimated; PAH, polycyclic aromatic hydrocarbon; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)] Detection Median detected Maximum detected frequencies concentration concentration OWC class Compound name (percent) (μg/L)‡ (μg/L), and site* Base Storm- Pore Base Storm- Pore Base flow Stormflow Pore water flow flow water flow flow water Caffeine 52 77 0 e0.105 e0.149 ND 0.66, LCM 0.711, KRM ND Human drugs, Cotinine 2 10 0 e0.0299 e0.0853 ND e0.0315, MRJ e0.349, KRM ND nonprescription Menthol 5 36 0 e0.0401 e0.160 ND 0.31, HCW 0.317, KRM ND 3-beta-Coprostanol 18 31 10 e0.442 e0.569 e1.03 e4.26, LMM e2.16, MRW e1.03, KRM beta-Sitosterol 24 71 70 e0.924 e1.4 e1.07 e3.15, MRC e5.08, KRM e2.45, KRM Sterols beta-Stigmastanol 7 3 50 e0.664 e0.793 e0.47 1.15, OSM e0.793, KRM e0.921, KRM Cholesterol 73 77 90 e0.586 e0.917 e1.59 e6.18, LMM e4.55, KRM e6.63, RRG 1,4-Dichlorobenzene 11 8 50 e0.0395 e0.0093 e0.0297 e0.108, MRJ e0.0245, OSM e0.073, LMM Miscellaneous Methyl salicylate 1 3 0 e0.0206 e0.0158 ND e0.0206, MRW e0.0158, OSM ND Tribromomethane 25 8 20 e0.014 e0.0114 e0.0117 e0.0299, KRM e0.0131, OSM e0.014, HCW (bromoform)

* Site abbreviations are defined in table 1.** Indicates compounds considered by the authors to be domestic wastewater-indicator compounds, likely from sanitary sewer sources.‡ Determined from only those samples with detections.
Table 4b 41

Table 4b. Organic waste compounds with known aquatic toxicity benchmarks for water samples, southeast Wisconsin, 2006–9.[OWC, organic waste compound; μg/L, micrograms per liter; EPA, U.S. Environmental Protection Agency; --, no data; PAH, polycyclic aromatic hydrocarbon; red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)]

OWC class Compound name

Aquatic toxicity benchmarks 

from EPA

Aquatic toxicity benchmarks 

from other sources

Percentage of samples exceeding lowest 

aquatic toxicity benchmark

Acute 

(μg/L)

Chronic 

(μg/L)

Acute 

(μg/L)

Chronic 

(μg/L) Base flow Stormflow Pore water

PAHs

Anthracene 86.1B 20.7B 13F .012D 17 72 90

Benzo[a]pyrene 3.98B .957B .24F .015D 19 92 90Fluoranthene 29.6B 7.11B 3,980F .04D 46 95 90Naphthalene 803B 193B 190F 1.1D 0 0 0Phenanthrene 79.7B 19.1B 30F .4D 0 51 50Pyrene 42B 10.1B -- .025D 53 95 90

Plasticizers Bis(2-ethylhexyl) phthalate (DEHP) -- -- 400F .3F 1 23 0 Diethyl phthalate -- -- 1,800F 110F 0 0 0Fuels

1-Methylnaphthalene -- -- 37F 2.1F 0 0 02-Methylnaphthalene -- -- -- 330F 0 0 0Isopropylbenzene (cumene) 2,140A 420A -- -- 0 0 0

Solvents Isophorone -- -- 117,000F 920F 0 0 0 Tetrachloroethene (PERC) -- -- 830F 45F 0 0 0Herbicides

Atrazine -- -- -- 1.8D 0 0 0Bromacil -- -- -- 5.0D 1 0 0Metolachlor -- -- -- 7.8D 0 0 0Pentachlorophenol (PCP) 19C 15C -- -- 0 0 0

Insecticides

Carbaryl 2.1C 2.1C 3.3D .2D 1 0 0Chlorpyrifos .083C .041C .02D .02D 0 0 0Diazinon .17C .17C .2E .07E 0 0 0

Antimicrobial disinfectants Phenol -- -- 10,200F 180F 0 0 0Detergent metabolites 4-Nonylphenol (sum of all isomers)** 28C 6.6C -- 1.0D 0 28 20Miscellaneous 1,4-Dichlorobenzene -- -- 180F 9.4F 0 0 0 Tribromomethane (bromoform) -- -- 2,300F 320F 0 0 0

** Indicates compounds considered by the authors to be domestic wastewater-indicator compounds, likely from sanitary sewer sources.A U.S. Environmental Protection Agency, 2008.B U.S. Environmental Protection Agency, 2003.C U.S. Environmental Protection Agency, 2012a.D Canadian Council of Ministers of the Environment, 2012.E Palumbo and others, 2012.F Buchman, 2008.
42 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Table 5a. Organic waste compounds sampled and summary of analytical results of sediment samples, southeast 

Wisconsin, 2006–9.—Continued

[OWC, organic waste compound; μg/kg, micrograms per kilogram; ND, not detected; -, not applicable; e, estimated; PAH, polycyclic aromatic hydrocarbon; 

red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)]

OWC class Compound name

Detection 

frequency 

(percent)

Median 

detected 

concentration

 (μg/kg)‡

Maximum 

detected 

concentration

Value 

(μg/kg) Site* 

Antioxidants 3-tert-Butyl-4-hydroxyanisole (BHA) 0 ND ND -

Bisphenol A 81 e98.42 e1,500 LMM

Dyes/pigments 9,10-Anthraquinone 96 625 1,630 LMM

Fire retardants

BDE congener 47 (tetrabromodiphenyl ether)** 0 ND ND -

Tributyl phosphate** 4 e20.4 e20.4 OSM

Tris(2-butoxyethyl) phosphate** 11 e161 e324 HCW

Tris(dichloroisopropyl) phosphate (Fyrol FR 2)** 4 e3.13 e3.13 MRW

PAHs

Anthracene 93 364 1,690 KRM

Benzo[a]pyrene 96 1,230 3,360 KRM

Fluoranthene 100 4,370 14,900 MRW

Naphthalene 71 88.5 278 KRM

Phenanthrene 100 2,320 7,630 MRW

Pyrene 100 3,460 10,600 MRW

Plasticizers

Bis(2-ethylhexyl) phthalate (DEHP) 75 567 1,930 KRM

Diethyl phthalate 4 88.9 88.9 LMM

Triphenyl phosphate 4 e37.7 e37.7 KRM

Tris(2-chloroethyl) phosphate (Fyrol CEF) 0 ND ND -

Fuels

1-Methylnaphthalene 75 e25.4 129 KRM

2,6-Dimethylnaphthalene 93 e30.3 e136 KRM

2-Methylnaphthalene 68 48.9 167 KRM

Isopropylbenzene (cumene) 4 e2.34 e2.34 LMM

Solvents Isophorone 18 e13.6 e21.5 LCM

Herbicides

Atrazine 0 ND ND -

Bromacil 0 ND ND -

Metolachlor 0 ND ND -

Prometon 0 ND ND -

Insecticides

Carbazole 93 324 810 KRM

Chlorpyrifos 0 ND ND -

Diazinon 0 ND ND -

N, N-diethyl-meta-toluamide (DEET) 0 ND ND -

Antimicrobial disinfectants

p-Cresol (para-Cresol) 96 e192 2,670 KRM

Phenol 61 e105 e753 UCW

Triclosan** 0 ND ND -
Table 5a 43

Table 5a. Organic waste compounds sampled and summary of analytical results of sediment samples, southeast 

Wisconsin, 2006–9.—Continued

[OWC, organic waste compound; μg/kg, micrograms per kilogram; ND, not detected; -, not applicable; e, estimated; PAH, polycyclic aromatic hydrocarbon; 

red compound names indicate known or suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)]

OWC class Compound name

Detection 

frequency 

(percent)

Median 

detected 

concentration

 (μg/kg)‡

Maximum 

detected 

concentration

Value Site* (μg/kg)

Detergent metabolites

Flavors and fragrances

Human drugs, nonprescription

Sterols

Miscellaneous

 4-tert-Octylphenol monoethoxylate**

4-Cumylphenol**

4-Nonylphenol (sum of all isomers)**

4-Nonylphenol diethoxylate**

4-Nonylphenol monoethoxylate**

4-Octylphenol (4-normal-Octylphenol)**

4-tert-Octylphenol diethoxylate**

4-tert-Octylphenol**

3-Methyl-1H-indole (skatol)

Acetophenone

Acetyl hexamethyl tetrahydro naphthalene (AHTN)**

Benzophenone**

Camphor**

d-Limonene**

Hexahydrohexamethyl cyclopentabenzopyran (HHCB)**

Indole

Isoborneol**

Isoquinoline**

Menthol

3-beta-Coprostanol

beta-Sitosterol

beta-Stigmastanol

Cholesterol

1,4-Dichlorobenzene

4

54

82

14

11

0

0

21

86

50

0

0

0

18

11

89

0

4

0

57

96

82

96

18

e114

112

e907

e606

e373

ND

ND

e29.4

e21.4

e46.6

ND

ND

ND

e29.7

e15.4

237

ND

e6.0

ND

e229

e3,670

e577

e1,380

e57.2

e114

1,270

e3,100

e1,520

e463

ND

ND

e48.5

74.9

e220

ND

ND

ND

e59.5

e16.3

717

ND

e6.0

ND

e937

e13,200

e2,450

e4,420

e72.3

KRM

LMM

MRW

MRW

MRW

-

-

KRM

KRM

KRM

-

-

-

LCM

LCM

LCM

-

HCW

-

KRM

LCM

MRW

KRM

LCM

‡

 Determined from only those samples with detections.

*

 Site abbreviations are defined in table 1.

** Indicates compounds considered by the authors to be domestic wastewater-indicator compounds likely from sanitary sewer sources.
44 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Table 5b. Organic waste compounds with known aquatic toxicity benchmarks for sediment samples, southeast Wisconsin, 2006–9.

[OWC, organic waste compound; μg/kg, micrograms per kilogram; EPA, U.S. Environmental Protection Agency; --, no data; PAH, polycyclic aromatic 

hydrocarbon; ISQG, interim sediment quality guideline; AET, apparent effects threshold; PEL, probable effect level; red compound names indicate known or 

suspected endocrine disruptors, according to The Endocrine Disruption Exchange, Inc. (2011)]

OWC class Compound name

EPA 

freshwater 

sediment 

screening 

benchmark† 

(μg/kg)

Sediment toxicity benchmarks from other sources

Percentage 

of samples 

exceeding 

lowest 

benchmark

Value

 (μg/kg)

Criteria type 

and source

PAHs

Anthracene 57.2 46.9 ISQGD 82

Benzo[a]pyrene 150 31.9 ISQGD 89

Fluoranthene 423 111 ISQGD 93

Naphthalene 176 34.6 ISQGD 64

Phenanthrene 204 41.9 ISQGD 93

Pyrene 195 53 ISQGD 93

Plasticizers

Bis(2-ethylhexyl) phthalate (DEHP) 180 750 AETF 54

Diethyl phthalate 603 -- -- 0

Fuels

2-Methylnaphthalene 20.2 201 PELD 61

Isopropylbenzene (cumene) 86 -- -- 0

Herbicides Atrazine 6.62 -- -- 0

Insecticides

Chlorpyrifos 0.52 -- -- 0

Diazinon 2.39 -- -- 0

Antimicrobial disinfectants

p-Cresol (para-Cresol) 670 -- -- 14

Phenol 420 48 AETF 46

Detergent metabolites 4-Nonylphenol (sum of all isomers)** -- 1,400 ISQGD 29

Miscellaneous 1,4-Dichlorobenzene 599 -- -- 0

†

 U.S. Environmental Protection Agency, 2012b.

** Indicates compounds considered by the authors to be domestic wastewater-indicator compounds likely from sanitary sewer sources.

D Canadian Council of Ministers of the Environment, 2012.

F

 Buchman, 2008.
Appendix 1.

Appendix Summary of Test Conditions for Conducting Sediment-Toxicity Tests.
46 Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9

Appendix 1. Summary of Test Conditions for Conducting Sediment-Toxicity Tests1.

Parameter Conditions

Test type Whole sediment toxicity test with renewal of overlying water

Temperature 23 ± 1 degree Celsius

Light quality Wide-spectrum fluorescent lights

Illuminance About 500 to 1,000 lux

Photoperiod 16 light : 8 dark

Test chamber 400 milliliter polypropylene beaker

Sediment volume 100 milliliter

Overlying water volume 175 milliliter

Renewal of overlying water 2 volume additions per day

Age of organisms Third instar larvae or 9 to 12 days (Chironomus tentans)

7 to 14 days (Hyallela azteca)

Number of organisms/

chamber 10

Number of replicates/

treatment

8

Feeding 1.5 milliliter yeast/fish food/cereal daily to each test chamber (Hyallela azteca)

1 milliliter Tetramin flake fish food to each test chamber (1 milliliter contains 4 milligrams of dry solids) 

(Chironomus tentans)

Aeration None, unless dissolved oxygen in overlying water drops below 40 percent of saturation

Overlying water Dechlorinated tap water

Test chamber cleaning If screens become clogged during a test, gently brush the outside of the screen

Overlying water quality Hardness, alkalinity, conductivity, pH, and ammonia at the beginning and end of a test. Temperature, pH, 

and dissolved oxygen daily.

Test duration 10 days

Endpoints Survival and growth (dry weight)

Test acceptability Minimum mean control survival of 70 percent (Chironomus tentans)

Minimum mean control survival of 80 percent (Hyallela azteca)

1

 U.S. Environmental Protection Agency, 1994.
Publishing support provided by the U.S. Geological Survey

Science Publishing Network, Columbus and West Trenton Publishing 

Service Centers

For more information concerning the research in this report,

contact the

Director, Wisconsin Water Science Center

U.S. Geological Survey

8505 Research Way

Middleton, WI 53562

http://wi.water.usgs.gov/
Baldwin and others—Organic Waste Compounds in Streams: Occurrence and Aquatic Toxicity, Southeast Wisconsin, 2006–9—Scientific Investigations Report 2013–5104