Water Quality in the

Lake Erie-Lake Saint Clair Drainages

Michigan, Ohio, Indiana, New York, and Pennsylvania, 1996–98

U.S. Department of the Interior

U.S. Geological Survey

Circular 1203
POINTS OF CONTACT AND ADDITIONAL INFORMATION

Front cover: Marblehead Lighthouse, a symbol of Lake Erie, located on the Marblehead Peninsula, near Sandusky, 

Ohio. (Photograph from Ohio Lake Erie Commission, Toledo, Ohio). 

Back cover: left, waterways such as the harbor of the Ashtabula River, Ohio, are used for industry, commerce, and 

recreation; right, country roads and small farms are still common in some areas. 

The companion Web site for NAWQA summary reports:

http://water.usgs.gov/nawqa/summaryreports/

Lake Erie-Lake Saint Clair Drainages:

USGS State Representative

U.S. Geological Survey-Water Resources Division

6480 Doubletree Avenue

Columbus, Ohio 43229–1111

e-mail: shindall@usgs.gov

http://oh.water.usgs.gov/nawqa/

National NAWQA Program:

Chief, NAWQA Program

U.S. Geological Survey-Water 

Resources Division

12201 Sunrise Valley Drive, M.S. 413

Reston, VA 20192

http://water.usgs.gov/nawqa/

River Basin Assessments

Albemarle–Pamlico Drainage Basin (Circular 1157)

Allegheny and Monongahela River Basins (Circular

 1202)

Apalachicola–Chattahoochee–Flint River Basin 

 (Circular 1164)

Central Arizona Basins (Circular 1213)

Central Columbia Plateau (Circular 1144)

Central Nebraska Basins (Circular 1163)

Connecticut, Housatonic and Thames River Basins

 (Circular 1155)

Eastern Iowa Basins (Circular 1210)

Georgia–Florida Coastal Plain (Circular 1151)

Hudson River Basin (Circular 1165)

Kanawha–New River Basins (Circular 1204)

Las Vegas Valley Area and the Carson and Truckee

 River Basins (Circular 1170)

Lower Illinois River Basin (Circular 1209)

Long Island–New Jersey Coastal Drainages 

 (Circular 1201)

Lower Susquehanna River Basin (Circular 1168)

Mississippi Embayment (Circular 1208)

Ozark Plateaus (Circular 1158)

Potomac River Basin (Circular 1166)

Puget Sound Basin (Circular 1216)

Red River of the North Basin (Circular 1169)

Other NAWQA summary reports

Rio Grande Valley (Circular 1162)

Sacramento River Basin (Circular 1215)

San Joaquin–Tulare Basins (Circular 1159)

Santee River Basin and Coastal Drainages (Circular

 1206)

South–Central Texas (Circular 1212) 

South Platte River Basin (Circular 1167)

Southern Florida (Circular 1207)

Trinity River Basin (Circular 1171)

Upper Colorado River Basin (Circular 1214) 

Upper Mississippi River Basin (Circular 1211)

Upper Snake River Basin (Circular 1160)

Upper Tennessee River Basin (Circular 1205)

Western Lake Michigan Drainages (Circular 1156)

White River Basin (Circular 1150)

Willamette Basin (Circular 1161)

National Assessments

The Quality of Our Nation’s Waters—Nutrients and

 Pesticides (Circular 1225)
U.S. GEOLOGICAL SURVEY CIRCULAR 1203 

Water Quality in the

Lake Erie-Lake Saint Clair Drainages

Michigan, Ohio, Indiana, New York, and Pennsylvania, 1996–98

By Donna N. Myers, Mary Ann Thomas, Jeffrey W. Frey, Stephen J. Rheaume, 

and Daniel T. Button
Library of Congress Cataloging-in-Publications Data

The use of firm, trade, and brand names in this report is for identification purposes only and

does not constitute endorsement by the U.S. Government.

Free on application to the

U.S. Geological Survey

Information Services

Box 25286 Federal Center

Denver, CO 80225

Or call: 1-888-ASK-USGS

U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

2000

Water quality in the Lake Erie-Lake St. Clair Drainages, Michigan, Ohio, Indiana, New York, and Pennsylvania, 

1996–98 / by D.N. Myers...[et al.].

p. cm. -- (U.S. Geological Survey Circular ; 1203)

Includes bibliographical references.

ISBN 0-607-95421-3 (alk. paper)

1. Water quality--Erie, Lake, Watershed. 2. Water quality--Saint Clair, Lake, Watershed (Mich. and Ont.) I. 

Myers, Donna N. II. Geological Survey (U.S.) III. Series.

TD222.3 .W374 2000

363.739’42’097712--dc21

00-049458
CONTENTS

Contents III

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM.....................................................................IV

SUMMARY OF MAJOR FINDINGS..............................................................................................................1

Stream and River Highlights ........................................................................................................... 1

Ground Water Highlights................................................................................................................. 2

INTRODUCTION TO THE LAKE ERIE-LAKE SAINT CLAIR DRAINAGES.................................................3

Major water-quality issues ......................................................................................................................3

Environmental setting and hydrologic conditions....................................................................................3

MAJOR FINDINGS .......................................................................................................................................6

Pesticides were detected in every stream sample..................................................................................6

The pesticides most frequently detected in streams were generally those most heavily 

applied ................................................................................................................................................ 7

Pesticide metabolites were frequently detected......................................................................................7

Pesticide concentrations in streams are related to land use, rainfall, runoff, and season ......................8

Pesticide concentrations in streams have public-health and economic consequences .........................8

Another consequence of heavy pesticide use is the potential effect on aquatic life ...............................9

NATIONAL PERSPECTIVE—Concentrations of nutrients and herbicides in certain streams are 

among the highest in the Nation....................................................................................................... 10

Runoff from agricultural land to streams is an important pathway of phosphorus to Lake Erie ........... 10

Decreases in the amounts of suspended sediment carried by rivers correspond to 

increases in farmers’ use of conservation tillage ....................................................................... 12

Contamination of bed sediments may be causing adverse effects on aquatic life........................ 13

Land use and chemical use contribute to the contamination of sediments and fish............................ 14

Bioaccumulative contaminants in fish may pose a risk to fish-eating wildlife ...................................... 15

Land use appears to affect fish-community composition .............................................................. 16

Recent residential development has had a widespread effect on ground-water quality...................... 18

Ground water is vulnerable to contamination in agricultural areas underlain by till ............................. 20

NATIONAL PERSPECTIVE—Nitrate and herbicides in ground water in agricultural areas ................ 22

STUDY-UNIT DESIGN............................................................................................................................... 23

GLOSSARY............................................................................................................................................... 25

REFERENCES .......................................................................................................................................... 27

APPENDIX–WATER-QUALITY DATA FROM THE LAKE ERIE-LAKE SAINT CLAIR DRAINAGES IN A 

NATIONAL CONTEXT...................................................................................................................... 29
NATIONAL WATER-QUALITY ASSESSMENT PROGRAM

IV National Water-Quality Assessment Program

THIS REPORT summarizes major findings about water quality in the Lake Erie-Lake Saint Clair Drainages that 

emerged from an assessment conducted between 1996 and 1998 by the U.S. Geological Survey (USGS) National 

Water-Quality Assessment (NAWQA) Program. Water quality is discussed in terms of local and regional issues and 

compared to conditions found in all 36 NAWQA study areas, called Study Units, assessed to date. Findings are also 

explained in the context of selected national benchmarks, such as those for drinking-water quality and the protection 

of aquatic organisms. The NAWQA Program was not intended to assess the quality of the Nation’s drinking water, 

such as by monitoring water from household taps. Rather, the assessments focus on the quality of the resource itself, 

thereby complementing many ongoing Federal, State, and local drinking-water monitoring programs. The comparisons made in this report to drinking-water standards and guidelines are only in the context of the available untreated 

resource. Finally, this report includes information about the status of aquatic communities and the condition of instream habitats as elements of a complete water-quality assessment.

 Many topics covered in this report reflect the concerns of officials of State and Federal agencies, water-resource 

managers, and members of stakeholder groups who provided advice and input during the Lake Erie-Lake Saint Clair 

Drainages assessment. Residents who wish to know more about water quality where they live will find this report 

informative as well.

THE NAWQA PROGRAM seeks to improve scientific and public understanding of water quality in the Nation’s 

major river basins and ground-water systems. Better understanding facilitates effective resource management, accurate identification of water-quality priorities, and successful development of strategies that protect and restore water quality. Guided by a nationally consistent study design and shaped by ongoing communication with local, State, 

and Federal agencies, NAWQA assessments support the investigation of local issues and trends while providing a 

firm foundation for understanding water quality at regional and national scales. The ability to integrate local and 

national scales of data collection and analysis is a unique feature of the USGS NAWQA Program.

 The Lake Erie-Lake Saint Clair Drainages is one of 51 water-quality assessments initiated since 1991, when the 

U.S. Congress appropriated funds for the USGS to begin the NAWQA Program. As indicated on the map, 36 assessments have been completed, and 15 more assessments will conclude in 2001. Collectively, these assessments cover 

about one-half of the land area of the United States and include water resources that are available to more than 60 

percent of the U.S. population.

1991-95

1994-98

1997-2001

Not yet scheduled

High Plains Regional

Ground Water Study, 

1999-2004

NAWQA Study Units 

Assessment schedule

Lake Erie-Lake Saint Clair Drainages
SUMMARY OF MAJOR FINDINGS

Summary of Major Findings 1 

Stream and River Highlights

Water quality in the Lake ErieLake Saint Clair Drainages is greatly 

influenced by land use and human 

activities. A major pathway for contaminant transfer from the land surface to streams is storm runoff from 

urban and agricultural areas. 

As a result of herbicides in runoff, 

concentrations in streams were in the 

top 25 percent of streams nationwide 

and many public-water supplies must 

treat stream water to reduce herbicide 

concentrations. As a result of nutrients in runoff, concentrations of total 

phosphorus and nitrate in some small 

streams in agricultural areas and in 

major rivers were in the top 25 percent of streams 

nationwide. Concentrations of nitrate, although elevated relative to many other streams in the Nation, 

were infrequently greater than the drinking-water standard of 10 milligrams per liter. 

Contamination of the bed sediments of small 

streams and major rivers by persistent and bioaccumulative contaminants was prevalent. The highest concentrations of PCBs (polychlorinated biphenyls) and 

mercury were detected in streams draining highly populated urban and mixed land-use areas. Detections of 

contaminants in fish tissues indicate bioaccumulation; 

in fact, bioaccumulation of PCBs and DDT in some 

fish species presents a health risk to fish-eating wildlife. 

• The pesticides detected most frequently were among those

applied in the greatest quantities to agricultural and mixed

land-use areas. The herbicides atrazine, acetochlor, cyanazine, metolachlor, and simazine were detected in 50 to 100

percent of samples. (p. 6) 

• Several heavily used herbicides and insecticides were detected in spring and summer at or above a standard for drinking water or a guideline for aquatic life. Elevated pesticide

concentrations in streams persisted for 4 to 6 weeks after applications in agricultural and mixed-land-use areas. (p. 8) 

• Annual average concentrations of total phosphorus were

greater than the U.S. Environmental Protection Agency recommended level for control of nutrient enrichment at 8 of 10

sites sampled in small streams and major rivers draining agricultural and mixed-use land. Streams draining row-crops

and mixed-use land are major pathways of phosphorus to

Lake Erie. (p. 10) 

Small streams Major rivers

Urban Row crop Pasture/

forest

Pesticides1 

Nitrate3

Indicators of Stream Quality 

Arsenic4

Polycyclic

aromatic

hydrocarbons5

Polychlorinated

biphenyls5

Other trace

elements4

Total 

phosphorus 2

Mixed

Percentage of samples with concentrations equal to or 

greater than a health-related national guideline for 

drinking water, aquatic life, or above a national goal for 

preventing excess algal growth (

a Percentage is 1 or 

less and may not be clearly visible.) 

Percentage of samples with concentrations less than a 

health-related national guideline for drinking water, 

aquatic life, or below a national goal for preventing 

excess algal growth 

(

b Percentage is 1 or less and may not be clearly 

visible.) 

1

2 Total phosphorus, sampled in water.

3 Nitrate (as nitrogen), sampled in water. 

4 Arsenic, cadmium, copper, lead, mercury, and zinc, sampled in sediment.

Insecticides, herbicides, and pesticide metabolites, sampled in water.

5 Industrial chemicals, combustion byproducts, and polychlorinated 

 biphenyls sampled in sediment.

c

 c c a

Percentage of samples with no detection 

(c Percentage is 1 or less and may not be clearly 

visible.) 

Land use in the Lake Erie-Lake Saint Clair Drainages was predominantly agriculand urban. This level of human activity has had substantial effects on water 

in the region.

tural

quality 

OHIO

INDIANA

OHIO

PA.

N.Y.

OHIO

MICHIGAN UNITED STATES

CANADA

LAKE ERIE LAKE

ST. CLAIR

MONROE

FINDLAY

ANN

ARBOR

LIMA

TOLEDO

DETROIT

WINDSOR

AKRON

CLEVELAND

ERIE

BUFFALO

SANDUSKY

41 ̊

42 ̊

43 ̊ 80 ̊

85 ̊

84 ̊

83 ̊

82 ̊

81 ̊

79 ̊

EXPLANATION

1970'S LAND USE UPDATED

WITH 1990 POPULATION DATA

Agriculture

Urban

Recent residential

Forest

Open water

Wetlands 20 40 60 MILES

0 20 40 60 KILOMETERS

0

Ohio

Pa.

N.Y.

Ind.

Mich.

Canada

Study

area

PA.

FORT

WAYNE
2 Water Quality in the Lake Erie-Lake Saint Clair Drainages

most other agricultural areas of the Nation. This observation

partially supports the belief that till or tile drains protect the

aquifer from contamination. Nevertheless, the ground water

is still vulnerable to contamination; almost 60 percent of shallow ground water contained herbicides or elevated concentrations of nitrate. Herbicides were predominantly detected as

breakdown products. (p. 20) 

• In residential and agricultural areas, samples from domestic

wells met health-related drinking-water standards. However,

ground water affected by human activities was detected at

depths below 25 feet, the minimum required depth for wells

in Ohio and Michigan. (p. 19) 

Major Influences on Ground-Water Quality

• Septic systems, roads, and lawns in residential areas

• Herbicides and fertilizer in agricultural areas

• Geology, especially deposits at land surface 

• Well depth and ground-water age

Trends in Ground-Water Quality

A significant change in ground-water quality is 

linked to recent residential development near Detroit. 

Ground water recharged before 1953 (which predates 

suburbanization) has concentrations of chemical constituents typical of natural water. In contrast, ground 

water recharged after 1953 has significantly higher 

concentrations of constituents derived from human 

activities.

• Contaminants detected most often in the bed sediments of

small streams and major rivers were arsenic, cadmium, copper, lead, mercury, zinc, PCBs, and PAHs (polycyclic aromatic hydrocarbons). The concentrations of arsenic, mercury,

PCBs, and PAHs were equal to or greater than sediment

guidelines, indicating probable adverse effects on aquatic

life, in about 11 to 30 percent of samples. (p. 13) 

• The most frequently detected contaminants in fish were

highly persistent contaminants—DDT, chlordane, dieldrin,

PCBs, and mercury. Except for mercury, use of these compounds in industry and agriculture in the United States was

discontinued 15 to 25 years ago. (p. 14) 

• Agricultural land use appears to be affecting fish communities in streams draining areas of row-crops. As the amount of

row-crops increased relative to forested land, the number of

pollution-intolerant fish species decreased. It appears that

pollution-intolerant fish can live where agriculture is the primary land use when streams are protected by natural cover.

(p. 17) 

Major Influences on Surface-Water Quality and 

Aquatic Biota

• Storm runoff

• Land use and chemical releases

• Bioaccumulative and persistent contaminants

Trends in Surface-Water Quality

 Suspended-sediment discharges from the Maumee 

River Basin decreased by 11.2 percent over the period 

1970–98 and corresponded to increased use of conservation tillage to control soil erosion.

Ground Water Highlights

The glacial aquifer is the major source of drinking 

water in the northwestern part of the study area. In this 

area, ground-water quality is affected by a combination of human and natural factors. Land use determines which chemicals are used; how readily these 

chemicals are transported to the ground water is 

affected by geology.

• In residential areas underlain by sand and gravel, more 

than 75 percent of ground water recharged since 1953 

shows evidence of human activities in the form of nitrate, 

chloride, or volatile organic compounds (VOCs). Probable 

sources are (1) septic systems containing human waste and 

household chemicals, (2) road salt and gasoline residue 

from paved surfaces, (3) waste from water softeners, or (4) 

lawn fertilizer. Pesticides were rarely detected. (p. 18) 

• In the agricultural study area, which is underlain by till, nitrate and herbicides were detected less frequently than in

Percentage of samples with concentrations equal to 

or greater than a health-related national guideline for 

drinking water.

Percentage of samples with concentrations less than

health-related national guideline for drinking water. 

Percentage of samples with no detection. 

Urban Agricultural

—

Domestic-supply

 wells

Indicators of Ground-Water Quality

1 Insecticides, herbicides, and herbicide metabolites, sampled 

 in water.

2 Nitrate (as nitrogen), sampled in water.

3 Solvents, refrigerants, fumigants, and gasoline compounds, 

 sampled in water.

Volatile

organics3

Pesticides1

Nitrate2

—

Shallow ground water

Not assessed.
INTRODUCTION TO THE LAKE ERIE-LAKE SAINT CLAIR DRAINAGES

Introduction to the Lake Erie-Lake Saint Clair Drainages 3 

Major water-quality issues

Streams and aquifers in the Lake 

Erie-Lake Saint Clair Drainages 

study area provide water for 10.6 

million people. The major waterquality issues in the study area are 

similar to those facing the rest of 

the Nation. Natural-resource managers are interested in the effects of 

urban and agricultural land use on 

the quality of surface water and 

ground water, specifically: 

• pesticide and nutrient contamination

of stream water used for public supply 

• nutrient enrichment and sedimentation

in streams and subsequent effects on

aquatic biota

• impairment of aquatic life from bioaccumulation of organochlorine compounds and mercury

• consumption advisories for certain fish

due to bioaccumulation of PCBs and

mercury

• degradation of ground water used for

domestic supply in areas of new residential development and areas of

row-crops

Environmental setting and 

hydrologic conditions

Lake Erie is the 11th-largest 

freshwater lake in the world. About 

two-thirds of the Lake Erie watershed is in the United States, and is 

referred to as the Lake Erie-Lake 

Saint Clair Drainages. (For simplicity, this area will be referred to 

as the “basin.”) This 22,300-

square-mile area includes sections 

of Michigan, Indiana, Ohio, Pennsylvania, and New York. The land 

surface is gently rolling to nearly 

flat lying. Eight major rivers, all 

with drainage areas greater than 

500 square miles, flow into the system.

Land use

In the Lake Erie-Lake Saint Clair 

Drainages, about 75 percent of the 

land area is in agriculture, 11 percent is urban land, 11 percent is 

forest, and 3 percent is open water 

or wetlands. (See land-use map in 

summary section.)

Corn, soybeans, and wheat are 

grown predominantly in the western part of the basin (fig. 1). Other 

agricultural land uses include pasture and forage crops, grown predominantly in the eastern part of 

the basin (fig. 2). Orchards and 

vineyards, located mainly along the 

shores of Lake Erie and in parts of 

Michigan, is the least widespread 

type of agricultural land use.

Urban land is an important component of land use in the basin (fig. 

3). Detroit and Pontiac, Mich.; 

Akron, Cleveland, Lima, and 

Toledo, Ohio; Fort Wayne, Ind.; 

Erie, Pa.; and Buffalo, N.Y., were 

historically significant contributors to industrial America through 

the production of automobiles, rubber, steel, petroleum, and chemicals. These cities remain important 

industrial and manufacturing centers. Major urban centers rely on 

abundant supplies of water for 

shipping, electric power generation, industry, domestic consumption, and waste assimilation.

Forest and wetlands, once common throughout the basin, have 

been greatly reduced since the mid1800s. The greatest percentage of 

forested land today is in Pennsylvania and New York. Metropolitan 

parks also support substantial 

urban forests. Wetlands lie primarily along Lake Erie and Lake Saint 

Figure 1. Agriculture is a major industry in the western part of the basin, where corn and soybeans are

grown. (Photograph from Natural

Resources Conservation Service.)

Figure 3. The port of Toledo, Ohio,

on the Maumee River exports large

amounts of grain from Midwestern

farms. Toledo is an industrial center

for automobile manufacturing. (Photograph from Ohio Lake Erie Commission.)

Figure 2. Pasture and forage crops

are found in the eastern part of the

basin.
4 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Clair from Detroit, Mich., to 

Sandusky, Ohio.

Geology

A layer of glacial deposits from 

20 to 200 feet thick mantles the 

entire basin and overlies limestone, 

sandstone, or shale bedrock. The 

glacial sediments consist of sand 

and gravel, till, and fine-grained 

sediments composed of fine sands, 

silts, and clay (fig. 4). Sand and 

gravel are present as discontinuous 

deposits in river valleys and in the 

western part of the basin.The most 

widespread deposit is till, a mixture 

of grain sizes. Tills in the Lake 

Erie-Lake Saint Clair Drainages 

contain a high 

content of clay, 

which slows infiltration of rainfall 

into the ground. 

Water use

More than 10.6 

billion gallons of 

water is used each 

day in the basin 

(fig. 5). Cooling 

during power generation accounts 

for 71 percent of the water use. 

Public and domestic supply 

account for 17 percent, and industry and mining account for 10 percent of the total use. Normal 

precipitation is generally adequate 

for agriculture, so irrigation 

accounts for less than 1 percent of 

water use. 

Of the more than 1.8 billion gallons per day used for public and 

domestic supply, about 88 percent 

is from surface-water sources. 

Most of the major cities are near 

Lake Erie and Lake Saint Clair and 

therefore derive their water from 

the lakes or their connecting channels (fig. 6). Major rivers are an 

important source of drinking water 

for inland cities such as Fort 

Figure 4. Glacial deposits throughout the basin influence the quality and flow of

surface water and ground water.

0

2,000

4,000

6,000

8,000

10,000

12,000

Ground water

Surface water

% of total withdrawals

WATER WITHDRAWALS,

IN MILLIONS OF GALLONS PER DAY

17%

71%

10% Less than

1 %

100%

TOTAL

THERMOELECTRIC

PUBLIC AND 

DOMESTIC SUPPLY

INDUSTRIAL

AND MINING

COMMERCIAL

AGRICULTURAL

Figure 5. Water withdrawals in the basin are 

dominated by thermoelectric power production.

Figure 6. Many public-water supplies with surface-water 

sources are near Lake Erie or major rivers, whereas publicwater supplies with ground-water sources generally are some

distance from the lake and major rivers.

UNITED STATES

CANADA

EXPLANATION

POPULATION SERVED

Less than 3,000

3,001 - 10,000

10,001 - 50,000

50,001 - 100,000

Greater than 100,000

Surface Water

UNITED STATES

CANADA

EXPLANATION

POPULATION SERVED

Less than 3,000

3,001 - 10,000

10,001 - 50,000

Greater than 50,000

Ground Water

BelleRiver

Rouge

River Raisin

River Maumee

River

Blanchard

River

St. Marys

River AuglaizeRiver

Sandusky

River

Black River

Cuyahoga

River BuffaloRiver Tonawanda

Creek

Black

River

River

Clinton River

H uron River

River

Tiffin St. Joseph

GrandRiver

CattaraugusCreek

OHIO

INDIANA

OHIO

MICHIGAN UNITED STATES

CANADA

LAKE ERIE LAKE

ST. CLAIR

MONROE

FINDLAY

ANN

ARBOR

LIMA

TOLEDO

DETROIT

FORT

WAYNE

AKRON

CLEVELAND

ERIE

BUFFALO

SANDUSKY

41 ̊

42 ̊

43 ̊ 80 ̊

85 ̊

84 ̊

83 ̊

82 ̊

81 ̊

79 ̊

EXPLANATION

SURFICIAL GEOLOGY

Sand and gravel

Clay and silt

Till

Water, exposed bedrock, 

other

20 40 60 MILES

0 20 40 60 KILOMETERS

0

OHIO

PA.

N.Y.

PA.
Introduction to the Lake Erie-Lake Saint Clair Drainages 5 

Wayne, Ind., and Akron and Lima, 

Ohio. 

About 12 percent of water for 

human consumption comes from 

ground water. The cities that use 

ground water as their major source 

of drinking water are generally 

inland (fig. 6). The most productive 

aquifers are in glacial deposits and 

limestone and sandstone bedrock. 

Hydrologic conditions

Average annual precipitation 

across the basin ranges from 28 to 

47 inches. Precipitation is highest 

in the northeast because of lake 

effect, whereby cool, dry air picks 

up moisture as it travels over 

warmer lake water and then produces rain or snow as it reaches 

land. The lowest amounts of precipitation are in the northwestern 

part of the basin in Michigan. During the study, annual precipitation 

was 4 to 5 inches above the 30-year 

mean annual. Some areas received 

13 inches of precipitation above the 

mean, and a few isolated areas 

received slightly less than the mean 

(fig. 7).

The highest streamflows are typically in February, March, and 

April, as a result of increased precipitation, cold temperatures and 

little vegetative growth. The lowest 

streamflows are in August, September, and October (Casey and 

others, 1997). During low streamflow, ground water typically contributes most of the flow.

Mean monthly streamflows for 

the Maumee River at Waterville, 

Ohio, at the west end of the basin, 

exceeded the long-term averages 

by a factor of 2 or more for some 

months in 1997–98 (fig. 8). Overall, the mean annual streamflow in 

the Maumee River was 25 percent 

above average during the sampling 

period. For Cattaraugus Creek at 

Gowanda, N.Y., at the east end of 

the basin, mean monthly streamflow during 1996–98 closely followed the long-term average (fig. 

8). In most areas of the basin, 

higher than average streamflows 

were observed in water years 

1996–98.

Increased streamflow tends to 

carry higher concentrations of 

materials associated with landsurface runoff. Low streamflow 

conditions tend to increase concentrations of materials associated 

with industrial and municipal discharges or ground water.

OHIO

INDIANA

OHIO

MICHIGAN UNITED STATES

CANADA

EXPLANATION

+13

-1

DEPARTURES FROM

30-YEAR MEAN

ANNUAL, IN INCHES

81 ̊

82 ̊

80 ̊

79 ̊ 83 ̊

84 ̊

85 ̊

43 ̊

42 ̊

41 ̊

OHIO

PA.

PA.

N.Y.

Figure 7. Departures from 30-year mean annual precipitation patterns for water 

years 1996–98, based on data from 133 weather stations.

Figure 8. Mean monthly streamflows during water years 1996–98 greatly 

exceeded long-term averages in some months.

18,000

O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S

15,000

12,000

900

600

300

0

600

2,400

1,800

1,200

S

0

TREAMFLOW, IN CUBIC FEET PER SECOND

Cattaraugus Creek at Gowanda, N.Y.

Maumee River at Waterville, Ohio

Mean monthly streamflow, water years 1996-98

Long–term mean monthly streamflow, 50+ years

1995 1996 1997 1998
6 Water Quality in the Lake Erie-Lake Saint Clair Drainages

MAJOR FINDINGS

The quality of streams and 

ground water in the Lake Erie-Lake 

Saint Clair Drainages is affected by 

a complex combination of natural 

factors (precipitation, streamflow, 

geology) and human factors (land 

use, chemical use, population density). Specific parts of the basin 

were targeted for investigation 

because they have particular combinations of natural and human factors. (See Appendix for details.) A 

primary factor that was found to 

influence water quality was land 

use, and this factor is emphasized 

throughout the report.

Pesticides were detected in 

every stream sample 

Between March 1996 and February 1998, 305 samples were collected from 10 streams in the basin. 

Every sample contained at least 

one pesticide, and most contained 

mixtures of several pesticides. 

Some samples contained a mixture 

of 18 pesticide compounds, which 

is among the highest number of 

pesticides detected in a sample 

nationally. 

 More pesticides were detected 

in large streams than small 

streams. Overall, 30 different pesticides were detected within the 

basin. The number of pesticides 

detected was greater in large 

streams and rivers that drain areas 

of mixed land use (urban and agricultural) than in smaller streams 

that drain basins dominated by a 

single land use. 

Urban and

agricultural

herbicides

Pasture/forest

Insecticides

Mixed

0

RowCrop

Metolachlor

Atrazine

Deethylatrazine

Cyanazine

Acetochlor

Alachlor

Metribuzin

Linuron

Simazine

DCPA

Prometon

2,4-D

Tebuthiuron

Diazinon

Chlorpyrifos

Carbaryl

Row-crop

herbicides

PERCENTAGE OF DETECTIONS

EXPLANATION

20 40 60 80 40 60 80 100 0 20 40 60 80 100

Urban

100 0 20 40 60 80 100 0 20

Figure 10. Metolachlor, atrazine, deethylatrazine, cyanazine, and simazine were the most frequently detected 

herbicides. Diazinon, chlorpyrifos, and carbaryl were the most frequently detected insecticides.

Metolachlor Atrazine

Cyanazine

Acetochlor

yanazine

Acetochl Alachlor

Glyphosate

Pendimethalin Pendimethal 2,4-D

Bentazon Dicamba

Metribuzin Dimethenamid Linuron

Acifluorfen Imazaquin

0

2,500,000

500,000

1,000,000

1,500,000

2,000,000

Chlorpyrifos

Carbaryl

Ethoprop

Endosulfan

Phorate

Azinphos-methyl

Methamidophos

Cryolite

Imidacloprid

Methyl Parathion

0

8,000

2,000

4,000

6,000

HERBICIDES

INSECTICIDES PESTICIDE USE, IN POUND

S

OF A

CTIVE IN

GREDIENT

Figure 9. A total of nearly 8.3 million pounds of pesticides 

was applied in the agricultural areas of the Lake Erie-Lake 

Saint Clair Drainages during 1994–95. (Data from Brody 

and others, 1997.) 
Major Findings 7 

The pesticides most 

frequently detected in 

streams were generally those 

most heavily applied 

Pesticide applications to crops in 

the Lake Erie-Lake Saint Clair 

Drainages are among the highest 

nationwide. The five most heavily 

applied agricultural pesticides—metolachlor, atrazine, 

cyanazine, acetochlor, and 

alachlor—were also among the 

most frequently detected (figs. 9 

and 10). Atrazine was detected in 

every stream-water sample collected during 1996–98 (fig. 10). 

Metolachlor was detected in 99 

percent of samples, and simazine 

was detected in greater than 80 percent of samples, regardless of land 

use (fig. 10). Two pesticides that 

are heavily used in the basin were 

not analyzed for in this study: (1) 

glyphosate, an herbicide used in 

agricultural and urban areas, and 

(2) endosulfan, an organochlorine 

insecticide, which was analyzed for 

in streambed sediment but not in 

water.

Pesticides detected more frequently in urban than in agricultural areas include the herbicide 

prometon and the insecticides diazinon and chlorpyrifos (figs. 10 and 

11). Chlorpyrifos (Dursban), which 

was detected in 22 percent of the 

samples, was recently restricted for 

residential and commercial use by 

the U.S. Environmental Protection 

Agency (USEPA).

Historical-use pesticides are 

seldom detected in water. Aldrin 

and DDT are organochlorine insecticides banned in the mid-1970s. 

Their metabolites (dieldrin and 

DDE) were each detected in about 

1 percent of stream samples. In 

contrast, total DDT was detected in 

nearly 35 percent of all streambed 

sediment samples (fig. 19, p. 13).

Pesticide metabolites were 

frequently detected

Little is known about pesticide 

metabolites (breakdown products) 

on a watershed level. After application, most pesticides adsorb to soil, 

infiltrate to ground water, volatilize, or break down to a metabolite 

(Larson and others, 1999). Deethylatrazine, a metabolite of atrazine, 

was detected in every sample collected during 1996–98. Additional 

triazine and acetanilide herbicides 

and their metabolites were intensively sampled for at one site, the 

St. Joseph River near Newville, 

Ind. Here, the metabolites of triazine compounds, like atrazine, 

showed the same seasonal pattern 

and relative concentrations as parent compounds. In contrast, concentrations of the acetanilide parent 

compounds—alachlor, acetochlor, 

and metolachlor—were lower than 

those of their metabolites for most 

of the year (fig. 12). 

1996 1997 1998

0

50

10

20

30

40

0

0.4

0.1

0.2

0.3

PESTICIDE CONCENTRATION,

IN MI

C

ROGRAM

S PER LITER

Auglaize River (row-crop basin)

Clinton River (urban basin)

ATRAZINE

DIAZINON

Maximum 85 μg/l

M A M J J A S O N D J F M A M J J A S O N D J F

Figure 11. The concentration of atrazine was higher in streams 

draining row-crops, whereas the concentration of diazinon was 

higher in streams draining urban-land use.

M J J A S O N D J F M A

1997 1998

0

3

1

2

STREAMFLOW,

IN CUBIC FEET PER SECOND 

0

6,000

1,000

2,000

3,000

4,000

5,000

PESTICIDE CONCENTRATION,

IN MICROGRAMS PER LITER 

STREAMFLOW

ALACHLOR

ALACHLOR ESA

ALACHLOR OA

St. Joseph River near Newville, Indiana

A

Figure 12. Metabolite concentrations for alachlor, as well as acetochlor 

and metolachlor (not shown), were greater than parent compounds for 

much of the year.
8 Water Quality in the Lake Erie-Lake Saint Clair Drainages

M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S

1996 1997 1998

0

25

5

10

15

20

STREAMFLOW,

IN CUBI

C FEET PER SECOND

0

10,000

2,000

4,000

6,000

8,000

ATRAZINE CONCENTRATION,IN MI

C

ROGRAMS PER LITER

STREAMFLOW

ATRAZINE

Maximum

Contaminant

Level

Figure 13. Pesticides such as atrazine show a seasonal trend with streamflow, as

shown for the St. Joseph River near Newville, Ind. Differences in the amount and

timing of precipitation affect the concentrations, as illustrated by the differences 

between the wet years of 1996–97 and the dry year of 1998.

Site and primary

land use

Auglaize River, Ohio 2.4 8.9

3.0

1.6 5.5

PASTURE/FOREST LAND USE

0.04

0.53 1.3

0.10

2.8

2.6 9.3

1

 Stream is used as a source of drinking water

River Raisin, Mich.

Black River, Mich.

St. Joseph River, Ind.

URBAN LAND USE

MIXED LAND USE

ROW-CROP LAND USE

Cattaraugus Creek, N.Y.

Maumee River, Ohio

Maumee River, Ind.

Cuyahoga River, Ohio

Clinton River, Mich.

Grand River, Ohio

Bold indicates concentration is greater than the

USEPA's aquatic-life guideline for atrazine of 1.8

micrograms per liter.

Concentrations of

atrazine

Annual

average

(μg/L)

May - July

average

(μg/L)

1

1

1

1

0.04 0.09

0.91

0.11

0.04 0.08

0.24

10.1

Table 1. Annual and seasonal time-weighted 

average concentrations of atrazine at 10 

stream sites in the Lake Erie-Lake Saint 

Clair Drainages, 1996–98

No benchmarks for metabolites 

have been set to protect human 

health or aquatic life, but some 

metabolites are believed to be as 

toxic as parent compounds (Day, 

1991). Because metabolites may 

account for a significant amount of 

the total pesticides in the environment, they are considered a waterquality concern.

Pesticide concentrations in 

streams are related to land 

use, rainfall, runoff, and 

season 

Herbicide concentrations were 

highest in streams draining rowcrops followed by streams draining 

mixed-use and urban land, and 

were lowest in streams draining 

pasture/forested land. Atrazine was 

detected at the highest concentrations, as high as 85 μg/L (micrograms per liter), in streams 

draining row crops and at much 

lower concentrations in streams 

draining urban land (fig. 11).

Rainfall and runoff affected the 

concentrations of atrazine in the 

wet years of 1996–97 compared to 

the dry year of 1998 in the St. 

Joseph River near Newville, Ind. 

(fig. 13). In 1996, streamflow was 

330 to 340 percent above average 

in May and June; in 1997, streamflow was 103 to 129 percent above 

average in May and June; and in 

1998, streamflow was only 36 to 

78 percent of the average. The 

median atrazine concentration 

detected in the stream was 0.40 

μg/L in 1996, 0.45 μg/L in 1997, 

and 0.14 μg/L in 1998. 

Herbicide concentrations in 

streams are typically highest 

after application and steadily 

decrease thereafter. Elevated concentrations of the most heavily 

used herbicides—metolachlor, 

atrazine, cyanazine, and acetochlor—were detected for 

4 to 6 weeks after rainfall 

and runoff in the spring 

and early summer (fig. 13, 

table 1). Pesticides used 

mostly in urban areas, such 

as prometon and diazinon, 

are typically applied in late 

summer, and this is when 

the highest concentrations 

were detected in streams 

(fig. 11).

Pesticide 

concentrations in 

streams have publichealth and economic 

consequences 

When concentrations of 

a contaminant in stream 

water are greater than a 

Maximum Contaminant 

Level (MCL), treatment 

might be needed to reduce 

the concentration (Box 1).

 The time-weighted average annual concentrations 

of atrazine were not greater 

than the drinking-water 

standard, or MCL, of 3 

μg/L at any of the 10 
Major Findings 9 

stream sites sampled during 1996–

98 (table 1). The values from May–

July, however, were greater than 

the MCL at five stream sites (table 

1), indicating a need for sourcewater treatment during that period 

to remove the pesticides. 

Many large water-treatment 

facilities that withdraw surface 

water (other than Lake Erie) use 

activated-carbon filtration during 

the spring to meet drinking-water 

standards. In areas of heavy pesticide use, specialized treatment may 

be necessary year round. For example, the Fort Wayne Water-Filtration Plant uses activated carbon all 

year. The annual cost of the treatment chemicals at Fort Wayne is 

approximately $210,000, about 40 

percent of this amount being spent 

from April to July (Doug Pooler, 

Fort Wayne Water Filtration Plant, 

oral commun., 1999). Even with 

carbon treatment, some treated 

drinking-water samples tested for 

atrazine were in excess of the MCL 

during 1996–98 

(Kelleher, 1999).

Another 

consequence of 

heavy pesticide 

use is the 

potential effect 

on aquatic life

Of the 10 streams 

sampled, 8 had pesticide concentrations, in single 

samples, in excess 

of one or more 

aquatic-life guidelines (fig. 14) (Frey, 

in press). Concentrations in excess of 

aquatic-life guidelines were 

detected for the herbicides atrazine, 

metolachlor, cyanazine, and 

metribuzin, and for the insecticides chlorpyrifos, carbaryl, and 

diazinon. Heavily used compounds—metolachlor, atrazine, 

cyanazine, and metribuzin—were 

the compounds with concentrations 

most frequently greater than guidelines. The time-weighted average 

concentration of atrazine, for 

example, was in excess of the 1.8-

μg/L guideline at 3 of 10 sites 

annually and at 5 of 10 sites during 

May–July (table 1).

Box 1—What concentrations of pesticides are considered safe in drinking water?

The USEPA sets drinking-water standards, or Maximum Contaminant Levels (MCLs), and health advisory–lifetime quidelines (HALs) for drinking water, to protect human health. The MCL is the maximum permissible concentration of a contaminant in water delivered to any user of public water systems. MCLs are enforceable standards and are based on an 

average annual concentration taken from quarterly samples of finished drinking water. HA (Health Advisories) are nonenforceable, risk-based guidelines. Health advisories indicate contaminant exposures below which no short- or long-term 

adverse human-health effects are expected, based on drinking a specific amount of water for a specific period of time. Risk 

of illness increases with exposure time and concentration. This report lists only HALs, which are based on a lifetime of 70 

years. Standards and guidelines to evaluate the potential adverse effects of pesticides have limitations: (1) Few standards 

and guidelines have been set for pesticides; of the 88 pesticides analyzed in this study, only 14 MCLs and 38 HALs have 

been established. (2) Drinking-water standards are based on toxicity tests on a single pesticide and do not evaluate the additive or synergistic effects of multiple pesticides. (3) The standards and guidelines do not address possible effects of pesticides on endocrine systems of humans (Nowell and Resek, 1994; Larson and others, 1999).

Box 2—What concentrations of pesticides are considered safe for aquatic life? 

Several agencies, including the USEPA, Environment Canada, and the IJC (International Joint Commission), have set guidelines to protect aquatic life. These guidelines are designed to prevent adverse short-term (acute) and long-term (chronic) effects on aquatic life. The aquatic-life guidelines or benchmarks developed by USEPA are based on 4-day average 

concentrations, are intended to protect 95 percent of the aquatic species, and should not be exceeded more than once in 3 

years. The Canadian and IJC aquatic-life guidelines, which are more stringent than those of the USEPA, indicate a single 

maximum concentration that should never be exceeded. Aquatic-life guidelines have been developed for only 18 pesticides.

Creek

Cattaraugus

Grand River

Clinton River

River Raisin

Black River

St. Joseph River

Auglaize River

Cuyahoga River

Maumee River,

 

 

 Ind.

 

Ohio

Maumee River,

0

30

10

20

NUMBER 

OF EX

CEEDAN

CES

PRIMARY LAND USE

Pasture/forest

Urban

Row crop

Mixed

Figure 14. The greatest number of concentrations of

pesticides affecting aquatic life were detected in streams

draining row crops and mixed-use land.
10 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Runoff from agricultural land 

to streams is an important 

pathway of phosphorus to 

Lake Erie

In the 1960s, Lake Erie was considered “dead” from the excessive 

growth and decay of algae and the 

oxygen-depleting effects of this 

decay on the bottom water of the 

lake (Herdendorf, 1986). By 1971, 

it was well known that the major 

sources of phosphorus to the lake 

were sewage, laundry detergents, 

and fertilizers. The Great Lakes 

Water-Quality Agreement (International Joint Commission, 1994) set 

goals for United States and Canada 

to reduce phosphorus inputs to the 

lake. Actions taken to reduce phosphorus included a limit on the 

phosphorus content of detergents, a 

limit of 1.0 mg/L in discharges 

from sewage-treatment plants, and 

a total load limit for Lake Erie of 

11,000 metric tons per year (International Joint Commission, 1994). 

Having achieved the point-source 

reductions over the period 1968–92 

(Litke, 1999), the focus shifted to 

reducing nonpoint sources of phosphorus. 

A sustained focus on reducing 

nonpoint sources of phosphorus to 

Lake Erie has continued because 

oxygen depletion in the bottom 

water in some areas occurs intermittently (Bertram, 1993; Litke, 

1999). One reason may be that in 

years with above-average runoff, 

annual phosphorus loads to the lake 

exceed 11,000 metric tons (Dolan, 

1993). The excess phosphorus in 

wet years is thought to come from 

nonpoint sources (Dolan, 1993).

Concentrations of nutrients and herbicides in certain streams

are among the highest in the Nation

Because the amounts of fertilizers and herbicides applied to agricultural areas are among the highest in the Nation, concentrations of nutrients and herbicides in stream water also are comparatively high at 8 of 10 streams 

sampled during 1996–98. In eight streams draining agricultural and mixed-use land, average annual concentrations of total phosphorus were in excess of the 0.1-mg/L (milligram per liter) guideline recommended by 

USEPA to reduce stream eutrophication (fig. 15). In four streams, phosphorus concentrations were in the upper 

25 percent of all streams sampled nationwide by NAWQA, as were nitrate concentrations in six streams. In two 

streams that serve as source waters for public supply, nitrate concentrations in a few samples were detected in 

excess of the drinking-water standard. Although total phosphorus concentrations appear to be relatively high, 

the work of other investigators has shown that concentrations of total phosphorus were 40 percent lower in 

1995 than in 1976 (Baker and others, 1998). In two of the streams where nutrient concentrations were in the 

upper 25 percent range on a national basis, average annual concentrations of herbicides were in the upper 25 

percent as well. Mixtures of pesticide compounds were found in every stream sample and a total of 30 different 

pesticides were detected. In one sample, 18 different pesticides were detected. This sample contained more pesticide compounds than 98.5 percent of all the samples collected at 343 sites across the Nation during 1993–98. 

Black

River

Tonawanda

Creek

BelleRiver

Clinton

River

Rive

H

r

uron

Rouge

Raisin

River

River

River

River Tiffin

Cuyahoga

Black

River

River

St. Joseph

River

Maumee

Blanchard River

St. Marys River

Sandusky

Cattaraugus

Creek

Buffalo River

Aug al ize River

River

Rive r

OHIO

INDIANA

OHIO

PA.

N.Y.

OHIO

MICHIGAN UNITED STATES

CANADA

LAKE ERIE LAKE

ST. CLAIR

MONROE

FINDLAY

ANN

ARBOR

LIMA

TOLEDO

DETROIT

WINDSOR

FORT

WAYNE AKRON

CLEVELAND

ERIE

BUFFALO

SANDUSKY

Agricultural land use

Urban land use

Mixed land use

AVERAGE ANNUAL CONCENTRATION

OF TOTAL PHOSPHORUS 

in milligrams per liter

Upper 25 percent (greater than 0.27)

Middle 50 percent (0.05 to 0.27)

Lower 25 percent (less than 0.05)

Bold outline indicates median value 

greater than USEPA desired goal of 0.1 

milligram per liter for prevention of 

nuisance plant growth in flowing waters

not discharging directly to lakes and 

impoundments

BACKGROUND CONCENTRATION

STREAM TYPE

EXPLANATION

EXPLANATION

Grand

PA.

Figure 15. Median concentrations of total phosphorus at 8 of 10 sites in the Lake

Erie–Lake Saint Clair Drainages were in excess of 0.1 milligram per liter, the USEPA

guideline to control eutrophication in streams.
Major Findings 11 

Fertilizers appear to be the 

major nonpoint sources of phosphorus to Lake Erie. Greater 

amounts of phosphorus were 

applied as fertilizers to each square 

kilometer of agricultural and 

mixed-use land than to urban-residential land in 1996–98 (fig. 16). 

Phosphorus yields, or the amount 

of phosphorus discharged from a 

stream per unit area of its basin, 

ranged from 8.2 to 293 kg/km2

(kilograms per square kilometer). 

The phosphorus yield from only 1 

of 10 streams sampled during 

1996–98 was in the lower range of 

yields typical of streams flowing 

through undeveloped land (Clark 

and others, 2000). Phosphorus 

yields in eight streams were similar 

to or slightly higher than the yields 

typical of streams flowing through 

agricultural and mixed-use lands 

(Gibson and others, 2000).

Phosphorus concentrations were 

highest in the same streams where 

yields were highest. Therefore, 

streams receiving runoff from agricultural and mixed-use lands contributed greater concentrations and 

amounts of phosphorus to Lake 

Erie than did streams receiving 

runoff from urban-residential land 

(fig. 16). A conclusion is that agricultural runoff is an 

important nonpoint source of 

phosphorus to 

small streams and 

major rivers and 

that major rivers, 

like the Maumee 

River, provide a 

direct pathway to 

Lake Erie. During 

1996–98, the 

Maumee River 

contributed an 

average of 24 percent per year to the 

11,000-metric-ton 

limit.

In the last few 

years, phosphorus 

concentrations in 

Lake Erie appear 

to be increasing 

above levels recommended in the 

Great Lakes WaterQuality Agreement (Scott Painter, Environment 

Canada, written commun., Oct. 

2000). Continued emphasis on 

managing levels of phosphorus in 

Lake Erie appears to be warranted 

(Box 3). 

Photograph from Ohio Lake Erie Commission.

Box 3—Recent changes in the food web of Lake Erie-the role of phosphorus and zebra mussels

Concerns about recent declines in some important fish species and the proliferation of zebra mussels, an exotic species, have 

prompted a renewed interest in the role of phosphorus in Lake Erie. Zebra mussels (shown in the photograph) were introduced 

into Lake Saint Clair in the mid-1980s and quickly became established in Lake Erie. Because of their filter-feeding behavior, 

zebra mussels may be affecting fish production in Lake Erie by consuming large amounts of small invertebrates and algae, or 

plankton, that are the food for small fish, which in turn are the food of larger game fish like yellow perch and walleye. Recent 

decreases in sport- and commercial-fish harvests, proliferation of zebra mussels, and 

reductions in phosphorus concentrations in Lake Erie have prompted a renewed interest in how factors such as phosphorus and zebra mussels may be affecting sustainable 

fish harvests. Adding more phosphorus to the lake to stimulate algal productivity has 

been suggested, but this could result in increased eutrophication of tributary streams 

and a return to excessive oxygen depletion in the bottom water of the lake. Furthermore, uncertainties about the response of the lake to phosphorus additions in light of 

its changing food web have held back plans to apply such a solution. One thing about 

which everyone can agree is the remarkable ability of exotic species to cause unexpected consequences in ecosystems (U.S. Environmental Protection Agency and Environment Canada, 2000).

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

Phosphorus inputs/outputs

Urban

Mixed

Row crop

Pasture/forest

Clinton River

Grand River

River Raisin

Cattaraugus Creek

Black River

St. Joseph River

Auglaize River

Cuyahoga River

Maumee River-New Haven

Maumee River-Waterville

TOTAL PHOSPHORUS,

IN KILOGRAMS PER S

QUARE KILOMETER

LAND USE

Figure 16. Unit-area phosphorus inputs to the land surface

from fertilizer and manure and unit-area phosphorus outputs from 10 streams in the Lake Erie-Lake Saint Clair

Drainages, 1996–98.
12 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Decreases in the amounts of 

suspended sediment carried 

by rivers correspond to 

increases in farmers’ use of 

conservation tillage

Cropland in the Maumee River 

Basin is the largest contributor to 

soil erosion and sediment in the 

Maumee River (U.S. Department 

of Agriculture, 1998), and the river 

is the largest tributary source of 

suspended sediments to Lake Erie 

(Myers and others, 2000). Excessive amounts of sediment discharged from the Maumee River to 

Lake Erie diminishes the aquatic 

habitats of fish and other organisms. Maintenance of navigation 

requires the dredging of approximately 800,000 tons of sediment 

each year from the Maumee River 

and Lake Erie at an average annual 

cost of about $2.2 million. In 

response to these problems, the 

Ohio Lake Erie Commission has 

set a goal of reducing suspended 

sediment in Lake Erie tributaries 

by 67 percent (Ohio Lake Erie 

Commission, 1998), and the U.S. 

Army Corps of Engineers has set a 

goal of reducing the amount of sediment dredged from the lower river 

and its harbor by 15 percent. 

Conservation tillage (fig. 17) is a 

reduced-cultivation method that is 

being used to decrease soil erosion 

and thereby the amount of suspended sediment carried by the 

Maumee River and its tributaries. 

By maintaining a layer of crop residue from the past year’s crop on 30 

percent or more of the soil surface, 

conservation tillage protects the 

soil from the forces of water erosion. During 1993–98, about 53 

percent of all crop fields in the 

Maumee River Basin and about 50 

percent of the crop fields in northwestern Ohio were planted using 

conservation tillage methods (fig. 

18).

Significant decreases in the 

amounts of suspended sediment 

carried by the Maumee and 

Auglaize Rivers over time correspond to increases in conservation tillage. Data from previous 

studies and new data collected at 

two sites in the Maumee River 

Basin during 1996–98 support this 

conclusion (Myers and others, 

2000). An 11.2-percent decrease in 

the amount of suspended sediment 

carried by the Maumee River was 

detected at Waterville, Ohio, near 

the mouth (fig. 18), and a 49.8-percent decrease was detected in the 

amount carried by the Auglaize 

River near Fort Jennings, Ohio, a 

tributary stream (Myers and others, 

2000). During 1970–98, no trends 

in streamflow at these two sites 

were detected. If conditions leading to the downward trends remain 

the same, then the estimated time 

necessary to achieve the 15 and 67 

percent reduction goals are 30.1 

and 205 years, respectively, from 

the reference condition in 1992. 

One reason for the smaller 

downward trend in the Maumee 

River compared to that found in its 

tributary may be related to drainage-basin size. In the large drainage basin of the Maumee River, 

sediment is deposited in small 

drainage ditches and streams. 

These stored sediments are available for resuspension and transport 

in subsequent storms.This process, 

as described by Trimble (1975, 

1999), creates a lag in the response 

of rivers to conservation tillage on 

the land.

Conservation tillage

Suspended-sediment

trend line

0.10

0.05

0.00

-0.05

-0.10

1970 1975 1980 1985 1990 1995

50

40

30

20

10

0

PERCENTAGE OF FIELDS IN CONSERVATION

TILLAGE IN NORTHWESTERN OHIO, 1982–98

STREAMFLOW-CORRECTED DAILY SUSPENDEDSEDIMENT, IN NATURAL LOG UNITS

Figure 18. Increases in conservation tillage in the Maumee 

River Basin and elsewhere in northwestern Ohio correspond 

to decreases in the amount of suspended-sediment carried 

by the Maumee River at Waterville, Ohio.

Figure 17. Conservation tillage protects

the soil. (Photograph by Steven Davis,

Natural Resources Conservation Service).
Major Findings 13 

Contamination of bed 

sediments may be causing 

adverse effects on aquatic 

life

Bed sediments of small streams 

and major rivers provide habitat 

for many aquatic organisms but 

also serve as a repository for persistent and toxic chemical contaminants that have been released into 

the environment or that occur naturally. Sediments, once contaminated, can provide a pathway for 

bioaccumulation. Activities such 

as dredging of sediments can 

release contaminants to the surrounding water.

Evidence from laboratory tests 

shows that contaminated bed sediments can be toxic to aquatic 

invertebrates (worms, clams, and 

insect larvae) that are of recreational, commercial, or ecological 

importance. Contaminated sediments also can affect the food 

supply required to sustain fish populations (U.S. Environmental Protection Agency, 1997). 

Data collected by the U.S. Geological Survey (USGS) and other 

public-sector agencies at more than 

800 locations from 1990 to 1997 

were aggregated and analyzed to 

assess bed-sediment contamination. These data show that zinc, 

lead, copper, arsenic, cadmium, 

mercury, PAHs (polycyclic aromatic hydrocarbons), PCBs 

(total polychlorinated biphenyls), DDT, and its breakdown 

products are prevalent in bed 

sediments, being detected in 30 to 

100 percent of samples (Rheaume 

and others, in press) (fig. 19). 

Concentrations of mercury and 

PCBs (figs. 20 and 21) exceeded 

Probable Effect Levels (PELs) in 

11.8 and 22.4 percent of samples, 

respectively. PELs are the guidelines established for the protection 

of aquatic life (Box 4). Contamination of bed sediments with mercury 

and PCBs was greatest in nearshore 

areas of Lake Erie, in Lake Saint 

Clair, and in major rivers that flow 

through urban areas with industry 

and populations over 100,000.

Concentrations of arsenic, DDT, 

and chlordane also exceeded PELs 

in the bed sediments of some 

smaller streams. Samples with 

detection limits higher than 

Threshold Effect Levels (TELs) 

(open circles, figs. 20 and 21) were 

not useful for assessment purposes. 

Lower detection limits would have 

made these data more useful. 

Box 4—How are contaminated sediments evaluated?

Effect levels are screening values used to indicate when contaminant concentrations in the bed sediments are likely to be associated with adverse effects on 

aquatic life. The Threshold Effect Level (TEL) is an estimate of the concentration of a contaminant in bed sediment below which adverse biological effects 

rarely occur and, if so, only in very sensitive species. The Probable Effect Level 

(PEL) is an estimate of the concentration of a contaminant in bed sediment 

above which adverse biological effects frequently occur. These guidelines were 

developed for the Great Lakes sediments and are used for national assessment in 

this report. For anthracene and total PAHs, no guideline was available from 

Smith and others (1996), so guidelines developed by Ingersoll and others (1996) 

for the Great Lakes were used.

0

10

20

30

40

50

60

70

80

90

100

CONTAMINANT

Zinc

Anthracene

Total PCB

Total DDT

Benzo[a]pyrene ]p

Benz[a]anthracene

a

Phenanthrene

Chrysene

Total PAH

Mercury

Cadmium

Copper

Arsenic

Lead

Mirex + Photomirex

Hexachlorobenzene

Lindane

Chlordane

Hexachlorocyclohexane

Dieldrin + Aldrin

PERCENTAGE

Percentage of samples in which contaminant

was detected

Percentage probability of being

great th P b bl Eff t L l er than a Probable Effect Level

Figure 19. Percentage detection and percentage probability of sample concentrations being greater than a Probable Effect Level in bed sediments of small streams,

major rivers, and lakes, Lake Erie-Lake Saint Clair Drainages, 1990–97. 
14 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Land use and chemical use 

contribute to contamination 

of sediments and fish

Most organochlorine pesticides 

and PCBs have not been manufactured or used in the United States 

for at least 10–25 years; however, 

because of their chemical stability 

(persistence), they were detected in 

bed sediments and fish collected in 

1996–98. Aldrin, DDT, and chlordane were the organochlorine 

insecticides used in the greatest 

quantities in the Corn Belt and 

Great Lakes States in the 1970s. 

Similarly, historical use of PCBs in 

industry contributed to their occurrence in urban and mixed-use 

areas. 

The highest concentrations of 

DDT, chlordane, dieldrin, and their 

breakdown products were detected 

in bed sediments and fish collected 

from small streams and major rivers flowing through row-crop, 

urban, and mixed-use lands. The 

highest concentrations of PCBs, 

DDT, and chlordane were detected 

in bed sediments and fish from 

streams flowing through urban and 

mixed-use lands where historical 

use was greatest. Organochlorine 

contamination was the lowest in 

fish and sediments collected from 

streams in pasture/forest settings.

Unlike organochlorine compounds, mercury has more than 

2,000 uses in industry, medicine, 

agriculture, and commerce. Mercury also is released to the atmosphere as a by-product of coal 

combustion and waste incineration 

(Irwin and others, 1997). In 1996–

97, mercury was detected in all 15 

bed-sediment samples and in all 11 

fish-liver samples collected from 

streams, independent of land-use 

type. The highest concentrations of 

mercury, however, were detected in 

bed sediments and fish collected 

from small streams and major rivers that flow through urban and 

mixed-use lands. The magnitude of 

mercury contamination in bed sediments and fish appears to follow 

patterns of use in commerce and 

industry. Mercury was detected in 

several different fish species that 

have different feeding habits and 

that occupy different positions in 

the food web. Mercury was 

detected in carp, which are bottomfeeders, in northern hog suckers, 

which eat insects, and in rock bass, 

which eat smaller fish (fig. 22).

UNITED STATES

CANADA

LAKE ERIE LAKE

ST. CLAIR

Aquatic effects (Smith and others, 1996)

TEL - Threshold Effect Level (0.174 mg/kg)

PEL - Probable Effect Level (0.486 mg/kg)

Total Mercury

EXPLANATION

Not detected; detection limit equal to

or greater than TEL

Less than TEL

Equal to or greater than TEL and

less than PEL

Equal to or greater than PEL and

less than 10 times PEL

Equal to or greater than 10 times PEL

and less than 100 times the PEL

Equal to or greater than 100 times PEL

CONCENTRATIONS, IN MILLIGRAMS 

PER KILOGRAM

Figure 20. Concentrations of total mercury in recently deposited lakebed and

streambed sediments (Data from 1990–97). 

UNITED STATES

CANADA

LAKE ERIE LAKE

ST. CLAIR

Aquatic effects (Smith and others, 1996)

TEL - Threshold Effect Level (0.0341 mg/kg)

PEL - Probable Effect Level (0.277 mg/kg)

Total PCB

Figure 21. Concentrations of total PCB in recently deposited lakebed and

streambed sediments (Data from 1990–97). 

Figure 22. Total chlordane, total DDT,

dieldrin, heptachlor epoxide, mercury,

and total PCBs were detected in the

tissues of carp, rock bass, and northern hog suckers collected in 1996–97.
Major Findings 15 

Bioaccumulative 

contaminants in fish may 

pose a risk to fish-eating 

wildlife

Where PCBs were detected in 

fish, they frequently posed a threat 

to fish-eating wildlife because of 

their high concentrations. PCBs 

were found in fish at 8 of 11 sites, 

and concentrations in fish from 6 

sites exceeded the New York State 

guideline for the protection of fisheating wildlife (table 2). The maximum concentration of PCBs found 

in fish was 25 times higher than the 

guideline set by the New York 

State Department of Environmental 

Conservation (NYSDEC) for the 

protection of fish-eating wildlife 

(Newell and others, 1987). These 

fish were collected from the Cuyahoga River at Cleveland, Ohio, a 

major river that flows through 

mixed-use land. 

DDT was present in fish at 10 of 

11 sites but concentrations in fish 

from only 2 sites exceeded the 

NYSDEC guideline. The highest 

concentrations of DDT were in 

whole fish in streams flowing 

through urban and mixed-use 

land—the Clinton River at Sterling 

Heights, Mich., and the Cuyahoga 

River at Cleveland, Ohio. Although 

mercury is a concern, no wildlife 

consumption guidelines have been 

established. 

Fish-consumption restrictions 

for humans are based on contaminant concentrations in edible fish 

fillets, which are typically lower 

than those in whole fish. The contaminants of most concern in the 

Lake Erie Basin for human consumption of fish are mercury, 

PCBs, DDT, chlordane, and dieldrin. These are the same contaminants that are a concern for wildlife 

consumption (fig. 23). Because of 

widespread human consumption 

advisories for fish in the Lake Erie 

Basin, mercury and PCBs have 

been identified as critical pollutants 

and targeted by the USEPA and 

Environment Canada for cleanup 

and elimination (Daher, 1999).

Compound found

in fish tissue

Number of

sites with

detections

(11 sites

sampled)

Maximium

detected

concentration (μg/kg)

NYSDEC whole-fish

quideline for the

protection of fisheating wildlife

(μg/kg)

Number of

sites with

contamination in

excess of

NYSDEC

criteria

Chlordane, total 6 157 500 0

DDT, total 10 450 200 2

Dieldrin 5 32.0 120 0

Heptachlor epoxide 2 10.0 100 0

PCBs, total 8 3,200 130 6

Table 2. Summary of contaminant concentrations in fish tissue in relation to guidelines for the protection of fish-eating wildlife [μg/kg, micrograms per kilogram;

NYSDEC, New York State Department of Environmental Conservation]

1. Contamimants are washed

 into water and build up in

 the sediment

2. Bottom-dwelling organisms

 such as zebra mussels 

 concentrate contaminants

 and are then eaten by goby

 and other small fish

3. Predator species like small

 mouth bass continue to

 concentrate toxins by eating

 the goby. Bass are then

 consumed by humans

Figure 23. Contaminants can bioaccumulate upward through the food web and may

affect the health of human and animal consumers of fish.
16 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Land use appears to affect 

fish-community composition

Contaminants and nutrients in 

water and bed sediments appear to 

affect aquatic life, but human disturbance of physical stream habitat 

also is thought to be one of the 

most important causes of declines 

in certain fish species (Ohio Environmental Protection Agency, 

1995). To differentiate the effects 

on fish of human disturbance from 

those of contaminants, sites considered to represent good to excellent 

stream habitat, as rated by the 

Qualitative Habitat Evaluation 

Index (QHEI) (Box 5) were 

selected for assessment of fish. 

Fish communities were assessed by 

means of the Index of Biotic Integrity (Box 5). 

 In 1996–98, stream habitats were

rated good to excellent at 11 of 13

sites (fig. 24A), but fish communities were rated good to excellent at

only 5 sites (fig. 24B). This may be

an indication that the contaminants

detected in water and bed sediments

Clinton River Fish Creek

W.Br. St. Joseph River E.Br. St. Joseph River

Br. St. Joseph River

E.Br. St. Joseph Riv River Raisin

eph River

River Rais

Auglaize River Black River

ze Rive

Black Ri St. Joseph River

Grand River Cattaraugus Creek Cuyahoga River raugus Creek ga Ri

Maumee River, Ind.

Maumee River, Ohio

0

160

20

40

60

80

100

120

140

PERCENTA

GE OF ATTAINMENT 

OF THE INDEX 

OF BI

OTIC

INTEGRITY (IBI)

0

100

20

40

60

80

QUALITATIVE HABITAT 

EVALUATION INDEX (QHEI)

PRIMARY LAND USE

URBAN

ROW CROP

PASTURE/FOREST

MIXED

No QHEI

EXPLANATION

A

B

Scores at or above the

line indicate the streamchannel habitat is rated

good to excellant

Scores at or above the

line indicate the fish

community is rated

good to excellant

Figure 24. Although most stream sites were rated good to excellent for habitat

as measured by the Qualitative Habitat Evaluation Index (A), only five sites

were rated good to excellent for fish community composition as measured by

the Index of Biotic Integrity (B).

Box 5—Index of Biotic Integrity and Qualitative Habitat Evaluation Index

Aquatic biological communities are sensitive indicators of stream quality. The biological condition of streams is 

evaluated within water-quality assessment programs by comparing the type, number, and abundance of fish species 

to those of streams known to be “least impacted” by human activities. The Index of Biotic Integrity (IBI), used by 

the Ohio Environmental Protection Agency (Ohio Environmental Protection Agency, 1989), also was used in this 

study to assess fish-community composition. IBI scores are derived by summing 12 individual metric scores from 

separate factors that describe fish communities. Examples of such metrics are the number of taxa, the number of 

insect-eating or omnivorous species, the number of pollution-tolerant and pollution-intolerant species, and the relative abundance of fish in each of these categories. Scores for the IBI range from 12 to 60; with ratings of poor, fair, 

good, and excellent quality assigned to numerical ranges. Higher scores indicate better overall fish-community 

diversity and abundance. Because the minimum IBI score required for a “good” rating differs somewhat from one 

ecological region to another, and there are five such regions in this study, each IBI score was reported as a percentage attainment of a “good” rating. A comparison of IBI scores computed independently for the same sites in the 

same years by the Ohio Environmental Protection Agency and USGS show that results are comparable between the 

two agencies as long as fish-collection methods are appropriate for the stream size (Covert, in press). A Qualitative 

Habitat Evaluation Index (QHEI), also developed by the Ohio Environmental Protection Agency (1989), was 

applied to data collected by USGS at the same stream sites where fish were assessed. The QHEI is composed of 

seven metrics that describe the physical habitat of streams: width, depth, pools, riffles, grain size of streambed substrates, and vegetation type and width along stream banks. Scores for the QHEI range from 0 to 100, with scores of 

60 or better indicating excellent stream-channel habitat.
Major Findings 17 

are affecting fish-community composition. 

For example, agricultural runoff appears to be affecting fish 

communities in streams draining row crops. Agricultural practices can heavily stress fish 

communities because 

of runoff of pesticides, nutrients, and 

sediments (figs.14–

16, 18–19). As the 

amount of row-crop 

agriculture increased, 

IBI scores at stream 

sites tended to 

decrease, although 

not proportionately 

(fig. 25A). In contrast, as the amount of 

forested land in a 

basin increased, IBI 

scores tended to 

increase. Forested 

lands, especially 

along the banks of 

streams, have been 

shown to be effective 

in removing sediment, pesticides, and nutrients that 

otherwise drain into streams with 

runoff from the land surface 

(Sweeney, 1992; Lowrance and 

others, 1997). 

Clear differences can be seen 

in fish-community composition 

among streams draining row-crops 

that may be related to the relative 

amount of row crops compared to 

woodlands and forests. As the 

amount of row-crops increased, the 

number of pollution-tolerant fish 

species in streams also increased 

(fig. 25B). In contrast, more pollution-intolerant fish species were 

found in streams draining areas 

with lower percentages of row 

crops and higher percentages of 

forested land in their basins, 

especially when the forests were 

along streams.

 Although only a few sites were

examined, it appears that pollution-intolerant fish can live in

streams where agriculture is the

primary land use under certain

conditions. This information corroborates the findings of others on

the water-quality benefits provided

by undisturbed natural stream habitats and wooded riparian areas (figs.

26 and 27).

0

60

10

20

30

40

50

INDEX OF BIOTIC

INTEGRITY (IBI)

Fish Creek

West Branch St. Joseph River

East Branch St. Joseph River

St. Joseph River

Black River Auglaize River

River Raisin

0 2 4 6 8 10

RATIO OF PERCENTAGE OF BASIN IN ROW CROPS TO PERCENTAGE

IN FOREST

0

10

5

INTOLERANT SPECIES (NUMBER)

Sites with percentages at or above the line are

comparable to "least impacted" sites

Auglaize River

Black River

Fish Creek

River Raisin

West Branch St. Joseph River

St. Joseph River p

East Branch

St. Joseph River

A

B

Figure 25. As the percentage of row-crop land use increased in a stream basin (A) scores for the Index of Biotic Integrity decreased and (B) the number of pollutionintolerant fish decreased.

Figure 26. High-quality stream habitat supports a variety of pollutionintolerant fish species along the West Branch of the St. Joseph River.Figure 27. Poor-quality stream habitat supports pollution-tolerant fish along the East

Branch of the St. Joseph River.
18 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Recent residential 

development has had a 

widespread effect on groundwater quality 

Two studies were done to assess 

ground-water quality in areas west 

of Detroit, where recent suburban 

development overlies sand-andgravel deposits (Thomas, 2000a). 

Recent suburban development typically consists of homes on large 

residential/rural lots or in uppermiddle-class subdivisions (fig. 28). 

Most homes have private wells, 

septic systems, and water softeners.

Samples of shallow and deep 

ground water were collected from 

co-located wells (fig. 29). Shallow 

ground water was sampled from 30 

monitor wells (median depth of 25 

feet). Deeper ground water was 

sampled from 28 domestic wells 

(median depth of 93 feet). In most 

places, clay till of varied thickness 

separates the shallow and deep 

sand-and-gravel deposits (fig. 29). 

Tritium concentrations were 

used to distinguish ground waters 

recharged before 1953 (“old 

waters”) from those recharged after 

1953 (“young waters”) (Plummer 

and others, 1993). Water in about 

one-third of domestic-wells was 

recharged before 1953, which is 

prior to widespread residential 

development in the study area. Old 

waters show no evidence of human 

activities. All nitrate concentrations were less than the estimated 

background value of 2 mg/L (U.S. 

Geological Survey, 1999), and all 

chloride concentrations were less 

than 25 mg/L, the estimated background concentration based on a 

historical data set from the same 

area (Mozola, 1953). 

In contrast, more than 75 

percent of young waters show 

evidence of human influence:

• Seventy-six percent of young 

waters had chloride concentrations 

greater than background (fig. 30). 

Probable sources of elevated chloride concentrations are road salt, 

septic systems, and backwash from 

water softeners. 

• Twenty-six percent of young 

waters contained nitrate concentrations greater than background (fig. 

30). Probable sources of elevated 

nitrate concentrations in residential areas are septic systems, lawn 

fertilizer, and pet waste.

• Trace concentrations of VOCs 

were detected in 29 of the 30 samples from monitor wells. The most 

frequently detected VOCs were 

BTEX compounds, which are components of fuels and solvents.

Samples that contained nitrate or 

VOCs also contained elevated 

Figure 28. Much of the recent development west of Detroit in the residential study

area consists of low- to medium-density subdivisions. Most homes have private

wells, septic systems, and water softeners.

0

200

100

50

150

250

EXPLANATION

WELL DEPTH, IN FEET

Sand and gravel

Till

Water table

30 monitor wells

 (median depth 25 feet)

28 domestic wells

 (median depth 93 feet)

Figure 29. Ground-water samples were collected from pairs of shallow monitor

wells and deeper domestic wells. Sand-and-gravel deposits are at land surface

and at varied depths in the subsurface. 
Major Findings 19 

chloride concentrations. The cooccurrence of these compounds suggests that ground water is affected 

by a mixture of sources, such as (1) 

septic systems containing domestic 

waste (nitrate and chloride), watersoftener backwash (chloride), 

and/or household solvents such as 

drain cleaners (VOCs), (2) infiltration of runoff from roads containing 

road salt (chloride) and fuel residue 

(VOCs), and/or (3) fertilizer or pet 

waste (nitrate) from lawns.

Pesticides were detected infrequently. Trace concentrations of 

herbicides were detected in 2 of 30 

(7 percent) monitor-well samples. 

This value is low compared to similar studies in 25 other urban/residential areas, where the median 

detection frequency of herbicides in 

shallow ground water was 44 percent (Kolpin, 2000). In the study 

area, most of the pesticides commonly used on lawns and roadways 

were analyzed for but were not 

detected in the shallow ground 

water. 

One monitor-well sample had a 

nitrate concentration exceeding 

health-related standards (fig. 30). 

The sample was from a well too 

shallow to be used as a source of 

drinking water, but shallow ground 

water can migrate to deeper parts of 

ground-water system or discharge to 

streams, lakes, and wetlands. 

No health-related drinking-water 

standards were exceeded in samples 

from domestic wells; however, standards do not exist for all compounds 

or for mixtures of compounds. Also, 

all possible constituents were not 

tested; for example, septic systems 

can contain bacteria, viruses, or 

pharmaceuticals. 

In Michigan, the minimum depth 

required for domestic wells is 25 

feet. In the study area, the effects of 

human activities were detected far 

below this depth (fig. 30). A proposal to increase the required depth 

for private wells in subdivisions is 

under consideration by the Michigan Department of Environmental 

Quality. 

0 5 10 15 20

0

275

25

50

75

100

125

150

175

200

225

250

WELL DEPTH, IN FEET

0 250 500 750 900

CONCENTRATION, IN MILLIGRAMS PER LITER

0

275

25

50

75

100

125

150

175

200

225

250 Background concentration g

Minimum well-depth

requirement i

EXPLANATION

Nitrate Chloride

MCL SMCL

Monitor well

Domestic well

Solid symbol: old water

Open symbol: young water

MCL: Maximum Contaminant Level—

 drinking-water standard

 based on health criteria

SMCL: Secondary MCL—

 drinking-water standard

 based on aesthetic criteria

Background concentration—

 estimated maximum concentration

 in ground water unaffected by

 human activities

Nitrate: 2 milligrams per liter

 (USGS,1999)

Chloride: 25 milligrams per liter

 (Mozola,1953)

Background concentration d

Figure 30. In the residential study area, concentrations of nitrate and chloride greater than background concentrations are the result of human activities. Elevated concentrations of chloride were detected far below 25 feet,

the minimum well depth required by State regulations. 

Box 6—Chloride/bromide 

ratios verify that elevated 

chloride concentrations are 

due to human activities. 

In parts of eastern Michigan, elevated chloride concentrations in shallow ground water have been 

attributed to upward movement of 

brine from deep bedrock formations 

(Mozola, 1953; Long and others, 

1988). In the study area, however, 

Cl/Br ratios indicate that elevated 

chloride concentrations were not 

derived from brine, but from halite 

(rock salt) (Davis and others, 1998). 

Natural sources of halite are not 

present in near-surface bedrock or 

sediments. However, halite is commonly used as road salt, table salt, 

and as a water-softener additive. 

The conclusion that elevated chloride concentrations are due to recent human activities is consistent 

with the observations that (1) chloride concentrations are highest in 

young, shallow waters, and (2) all 

old waters have concentrations that 

are less than background values. 
20 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Ground water is vulnerable to 

contamination in agricultural 

areas underlain by till 

Ground-water quality was 

assessed in agricultural areas in the 

northwestern part of the Lake ErieLake Saint Clair Drainages (Thomas, 2000b) (fig. 31). In this 

region, clay-rich till is at the land 

surface, and the rate of water infiltration is generally less than in the 

residential study area, where sand 

and gravel are at the surface (compare figs. 29 and 32).

Samples of shallow ground 

water were collected from 30 monitor wells installed in the till at a 

median depth of 18 feet. Deeper 

ground water, from the glacial 

sand-and-gravel aquifer, was collected from 18 domestic wells with 

a median depth of 90 feet (fig. 32). 

Samples were analyzed for pesticides in the form of parent compounds (the original active 

ingredient) and metabolites (breakFigure 31. In the agricultural study

area, the predominant crops are corn,

soybeans, and small grains. (Photograph from Ohio Department of Natural

Resources.) 

Sand and gravel

Till

Tile drains approx. depth 3 feet

Water table

18 domestic wells (median depth 90 feet)

30 monitor wells (median depth 18 feet)

50

100

150

0 EXPLANATION

WELL DEPTH, IN FEET

Figure 32. In the agricultural study area, clay-rich till occurs at land surface. 

Shallow tile drains are installed in low spots of farm fields to improve drainage.

0 10 20 30 40

METOLACHLOR

MM Metolachlor ESA

Metolachlor OA

ATRAZINE

Deethylatrazine

Cyanazine amide

Acetochlor ESA

Acetochlor OA

Alachlor ESA

Alachlor OA

BROMOXYNIL

EXPLANATION

Analysis from the USGS

Organic Chemistry Lab

Analysis from the USGS

National Water-Quality Lab

0 10 20 30

METOLACHLOR

ATRAZINE

CYANAZINE

ACETOCHLOR

ALACHLOR

OTHER

0.01

6.02

3.27

0.11

0.05

3.53

1.04

PERCENT TOTAL PESTICIDE USE PERCENTAGE OF SAMPLES IN WHICH

COMPOUND WAS DETECTED

0 10 20 30 40

0.009

0.02

1.52

0.97

0.12

Black letters: parent

compounds

ESA: ethanesulfonic acid

OA: oxalic acid

 27 monitor wells 18 domestic wells

PESTICIDES APPLIED PESTICIDES DETECTED

Blue letters: metabolites

Number to right of each bar

represents the maximum

concentration detected.

Detection frequencies are

based on varied reporting limits

Figure 33. Pesticides detected in the shallow ground water closely correspond to those most heavily applied in

the Lake Erie–Lake Saint Clair Drainages (data from Brody and others, 1997). All are herbicides used on corn

and soybeans. Metabolites were detected more frequently, and at higher concentrations, than parent compounds.
Major Findings 21 

down products). Pesticides were 

detected in 41 percent of monitor-well samples. The six compounds detected closely correspond 

to those most heavily applied in the 

basin—herbicides used on corn and 

soybeans (fig. 33). Metabolites 

were detected three times more frequently, and at higher concentrations, than were parent compounds. 

Concentrations did not exceed 

drinking-water standards, but standards do not exist for 9 of the 11 

compounds detected. In addition, 

many samples contained more than 

one herbicide, and the health effect 

of mixtures is unknown. 

 Nitrate concentrations indicative of human influence were 

detected in 37 percent of monitor-well samples. Probable sources 

are nitrogen fertilizers (which are 

heavily used in the study area), 

manure, or septic systems. Nitrate 

concentrations exceeded healthrelated drinking-water standards in 

two shallow monitor wells (fig. 

34). 

Pesticides and nitrate were 

detected much less frequently in 

domestic wells than in monitor 

wells (fig. 34). About 6 percent 

(1 of 18) of samples from domestic 

wells contained a trace concentration of a pesticide metabolite, and 6 

percent contained a nitrate concentration approximately equal to the 

background concentration of 2 

mg/L.

A common belief is that till 

protects the ground water from 

contamination. There appears to 

be some truth to this idea because 

detections of nitrate and herbicides 

are low relative to other agricultural areas with similarly high 

application rates. At the same time, 

this belief is a simplification that 

may be misleading because ground 

water is still vulnerable to contamination, especially at shallow 

depths. 

Fifty-nine percent of monitorwell samples showed evidence of 

human activity—either an herbicide or an elevated nitrate concentration. Moreover, 83 percent of 

waters from monitor wells were 

recharged after 1953. These observations indicate that till does not 

prevent water at the land surface 

from moving to the shallow 

ground water. In the study area, 

0 2 4 6 8 10 12 14 16

0

175

25

50

75

100

125

150

WELL DEPTH, IN FEET

Background

concentration

Solid symbol: old water

0.1 1 10 100 500

TRITIUM CONCENTRATION,

IN PICOCURIES PER LITER

Domestic well

Monitor well

0 1 2 3 4 5 6

MCL

EXPLANATION

Recharged

after 1953

MCL: Maximum Contaminant Level—

 drinking-water standard

 based on health criteria

Nitrate Pesticides Estimated

ground-water age

Minimum

well-depth

requirement

Recharged

before 1953

Open symbol: young water

NUMBER OF PESTICIDES

DETECTED

NITRATE CONCENTRATION,

IN MILLIGRAMS PER LITER

0

175

25

50

75

100

125

150

0

175

25

50

75

100

125

150

Figure 34. Detections of nitrate or pesticides are relatively infrequent at depths greater than 35 feet; however,

deeper ground water is not completely isolated from the land surface because almost half of the waters between depths of 35 and 100 feet were recharged after 1953.
22 Water Quality in the Lake Erie-Lake Saint Clair Drainages

till contains vertical fractures and 

numerous stringers of sand and 

gravel that are potential pathways 

for movement of water from the 

surface. In areas with similar geology to that in the agricultural study 

area, active ground-water flow 

occurs to depths of 35 feet, and 

sometimes much deeper (Keller 

and others, 1991). 

Similarly, till does not completely prevent water at the land 

surface from entering the deeper 

ground water. Eleven percent of 

domestic-well samples contained 

either a pesticide or elevated nitrate 

concentration. Moreover, almost 

half of the waters from domestic 

wells between depths of 35 to 100 

feet were recharged after 1953 (fig. 

34). 

Naturally occurring geochemical processes may be partly 

responsible for the relatively low 

detection frequencies of agrochemicals in the ground water. Till and 

till soils are generally rich in clay 

and organic matter and therefore 

are conducive to the sorption or 

breakdown of pesticides. Most of 

the pesticides detected were metabolites that had already been partially broken down (fig. 33).

Nitrate also can be transformed 

in the subsurface. In the presence 

of organic matter, low dissolvedoxygen concentrations are conducive to denitrification. Groundwater samples from 100 percent of 

the domestic wells and 50 percent 

of the monitor wells had dissolvedoxygen concentrations less than 1 

mg/L. In addition, the till contains 

numerous fragments of black shale 

rich in pyrite, a mineral that can 

also lead to denitrification (Robertson and others, 1996). 

Within the study area, the thickness and composition of the till are 

variable and not well defined in all 

locations. Therefore, the degree to 

which the till protects the ground 

water—by physical or geochemical 

means—is probably also variable 

and difficult to predict. 

 Low detections of agrochemicals

in ground water may be partly due

to tile drains, which can divert contaminants from the shallow ground

water to streams (Nolan and Stoner,

2000), but tile drains do not completely prevent contaminants from

reaching shallow ground water. Nitrate and pesticides were detected in

monitor wells 10 to 34 feet deep,

whereas tile drains are typically

about 3 feet deep. Vertical fractures

in the till can provide a direct pathway from the land surface to the

water table. 

In general, agrochemicals are most frequently detected where 

they are most heavily used; but exceptions to this pattern 

have been found (U.S. Geological Survey, 1999). For example, in the agricultural study area, detections of nitrate and 

herbicides in shallow ground water are among the lowest in 

the Nation even though nitrogen inputs and herbicide use are 

among the highest. In deeper ground water, nitrate and herbicide detections are also low relative to the Nation as a whole.

 A similar phenomenon has been noted elsewhere. In parts 

of the Midwest, the proposed explanations for low detections 

of nitrate in ground water are that (1) till impedes movement 

of contaminants from land surface, or (2) tile drains divert 

contaminants to streams (Fenelon, 1998; Nolan and Stoner, 

2000). In an area of the Southeast Coastal Plain, biogeochemical processes are the proposed cause of the low detections 

(Nolan and Stoner, 2000). In the study area, low detections of 

nitrate (and herbicides) are probably due to a combination of 

physical and geochemical processes. 

Median concentration

in milligrams per liter. Each circle

represents a ground-water study

Highest (greater than 5.1)

Medium (.48 to 5.1)

Lowest (less than .48)

Background concentration

Bold outline indicates median values

greater than background concentration

(2 milligrams per liter)

Average annual total

in pounds per acre, by county, for

1995-98. Inputs are from fertilizer,

Greater than 25

6 to 25

Less than 6 

Shallow ground water in agricultural areas

NITRATES 

manure, and the atmosphere

nitrogen input-- of nitrate--

EXPLANATION

Nitrate and herbicides in ground water in agricultural areas
STUDY UNIT DESIGN

Study Unit Design 23 

Stream Chemistry

A network of 10 stream sites was 

sampled for various chemical constituents and physical properties 

from March 1996 through February 

1998 (fig. 35, table 3). Sampling 

was done over a range of streamflows. Sites were sampled 18–32 

times per year; intensive sites were 

sampled more frequently than basic 

sites (table 3). 

Assessments of contaminants in 

streambed sediments and fish tissue were made at the 10 fixed 

streams sites and at one to five 

additional sites. Sediment samples 

were collected and sieved in the 

field. Whole fish were collected 

and analyzed for concentrations of 

organochlorine compounds. Fish 

livers were analyzed for traceelement concentrations.

Stream Ecology

Sampling was done at least once 

at 10 sites where water samples 

were collected. Multiple-year and 

multiple-reach sampling was done 

at three sites (table 3). Stream 

reaches ranged from 200 to 500 

meters in length. 

Fish surveys involved electrofishing and seining. Macroinvertebrates and algae were sampled 

from natural substrates. Habitats 

were assessed by identifying and 

mapping riparian vegetation and 

measuring geomorphic features of 

stream channels. Samples of bed 

and bank materials were collected 

and analyzed for grain size. 

BlackRiver

Tonawanda

Creek

Belle

C

River

linton

River

H

River

uron

Rouge

Raisin

River

GrandRiver

River

River

Tiffin

Cuyahoga

Black

River

River

St. Joseph

River

Maumee

Blanchard River

St. Marys

River

River

Sandusky

Cattaraugus Cr.

Buffalo

River

Augal ize

River

River

OHIO

INDIANA

OHIO

PA.

OHIO

MICHIGAN UNITED STATES

CANADA

LAKE ERIE LAKE

ST. CLAIR

MONROE

FINDLAY

ANN

ARBOR

LIMA

TOLEDO

DETROIT

WINDSOR

FORT

WAYNE

AKRON

CLEVELAND

ERIE

BUFFALO

4 SANDUSKY

5 6

7

8

2 10

1

3

9

11

12

13

14

15

EXPLANATION

Basin indicator of agricultural land use

Basin indicator of mixed land use

STREAM SAMPLING SITES

 1 Black River near Jeddo, Mich.

 2 Clinton River at Sterling Heights, Mich.

 3 River Raisin near Manchester, Mich.

 4 St. Joseph River near Newville, Ind.

 5 Maumee River at New Haven, Ind.

 6 Auglaize River near Ft. Jennings, Ohio

 7 Maumee River at Waterville, Ohio

 8 Cuyahoga River at LTV Steel, Cleveland, Ohio

 9 Grand River at Harpersfield, Ohio

10 Cattaraugus Creek at Gowanda, N.Y. 

11 Cedar Creek near Cedarville, Ind.

12 Huron River near Hamburg, Mich.

13 Clinton River near Drayton Plains, Mich.

14 Paint Creek at Rochester, Mich.

15 Fish Creek near Artic, Ind.

16 East Branch St. Joseph River, Ohio

17 West Branch St. Joseph River, Ohio

DETROIT

ANN ARBOR

EXPLANATION

GROUND-WATER STUDIES

Urban Land-Use Study

Agricultural Land-Use Study

Subunit Survey

Basin indicator of urban land use

-stream water and ecology

 -bed sediment and fish tissue

-bed sediment and fish tissue or fish

 communities

Fixed Site

Additional Sites

NiagaraRiver

Co-located wells in residential areas

Urban Drinking-Water Study

STREAM WATER AND

BIOLOGICAL STUDIES

17 16

PA.

N.Y.

Figure 35. Stream and ground-water sampling sites in the Lake Erie-Lake Saint Clair Drainages, 1996–98.
24 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Ground-Water Chemistry

Four ground-water studies were 

done in the northwestern part of the 

basin (fig. 35), where glacial 

deposits greater than 100 feet thick 

serve as the major source of drinking water. 

Two of the studies were done on 

the far outskirts of Detroit, where 

recent residential developments 

overlie sand and gravel. An urban 

land-use study was done by installing and sampling 30 shallow monitor wells (table 3). A second study 

involved sampling 28 domesticsupply wells, each of which was 

co-located with a monitor well. 

The agricultural land-use study 

was done in areas where corn and 

soybean row crops overlie clayrich till. Thirty shallow monitor 

wells were installed in the till and 

sampled for a various constituents, 

including pesticide metabolites.

The subunit survey involved 

sampling 28 domestic wells that 

produce water from the glacial 

aquifer in areas where it is overlain 

by till. Of the 28 wells, 18 were colocated with monitor wells in the 

agricultural land-use study area 

(fig. 35). 

Study

component What data were collected and why Types of sites sampled Number of sites

Sampling frequency 

and period

Stream Chemistry

Contaminants 

in streamwater—

 basic sites

Streamflow, pH, specific conductance, temperature and concentrations of nitrogen and phosphorus compounds, 

major ions, organic carbon, suspended sediment, herbicides, and E. coli were measured to determine occurrence 

and distribution of contaminants and other constituents

Streams draining areas ranging in size from 

132 square miles to 1,230 square miles 

reflecting agricultural, urban, and mixed 

land uses.

6 Monthly, plus storms and 

low flows from March 

1996 to February 1998

Contaminants 

in streamwater—

 intensive sites

Physical properties and chemical and microbiological constituents mentioned above plus insecticides and VOCs.Streams draining areas ranging from 310 

square miles to 6,330 square miles 

reflecting agricultural, urban, and mixed 

land uses.

4 Weekly to monthly, plus 

storms and low flows 

from October 1996 to 

September 1997, 

bracketed by monthly 

plus storms from 

March 1996 to February 1998

Contaminants 

in streambed 

sediment

Concentrations as dry weight of trace elements, semivolatile 

organic compounds, organochlorine compounds, and 

percent organic content. Determined to assess occurrence 

and distribution of contaminants.

Shallow depositional zones in a 300-meter 

reach at all 10 sites sampled for streamwater chemistry and at 5 additional sites

15 One to three times in 

June–October, 1996–

98

Contaminants 

in fish tissue

Concentrations of trace elements in fish liver and organochlorine compounds, such as PCBs and organochlorine pesticides, in fish tissue were analyzed to determine 

occurrence and distribution.

Resident fish such as carp, rock bass, and 

hog suckers at all sites sampled for 

stream-water chemistry and at one 

additional site

15 One to three times in 

June–October, 1996–

98

Stream Ecology

Aquatic biota at 

stream sites

Community composition of aquatic macroinvertebrates, 

algae, fish and stream habitat were surveyed to determine 

effects of water quality on aquatic biota.

Sites co-located with basic and intensive 

stream-water chemistry sites and at three 

additional sites

10 One to three times in 

June–October in 1996–

98

Ground-Water Chemistry

Subunit 

 survey 

Water level, pH, specific conductance, temperature and concentrations of nitrogen and phosphorus compounds, 

major ions, VOCs, organic carbon, insecticides, herbicides, herbicide degradates, radon, and tritium were measured to determine the quality of an aquifer that is an 

important source of drinking water. 

Domestic wells in the northwestern part of 

the Study Unit. Eighteen of the wells are

 co-located with monitor wells of the 

 agricultural land-use study.

28 Once, June–August 1998

Agricultural 

land-use 

study

Above measurements and compounds (except VOCs and 

radon) to determine the effects of agricultural land use on 

shallow ground water. 

Monitor wells in agricultural areas in 

northwestern part of Study Unit.

30 Once, June–August, 1998

Urban land-use 

study

Above compounds (plus VOCs and radon) to determine 

effects of recent residential development on shallow 

ground water.

Monitor wells in new residential areas near 

Detroit, Mich.

30 Once, September–

 December 1996

Special Study

Urban drinking-water 

study 

Same as for Subunit survey Domestic wells co-located with urban landuse wells in new residential areas near 

Detroit. 

28 Once, May–July 1997

TABLE 3. SUMMARY OF DATA COLLECTION IN THE LAKE ERIE-LAKE SAINT CLAIR DRAINAGES, 1996–98
GLOSSARY 

Glossary 25

Anthropogenic - A condition or occurrence that is the result 

of, or is influenced by, human activity. 

Aquifer - A water-bearing layer of soil, sand, gravel, or rock 

that will yield usable quantities of water to a well. 

Background concentration - A concentration of a substance in a particular environment that is indicative of 

minimal influence by human (anthropogenic) sources. 

Base flow - Sustained, low flow in a stream; ground-water 

discharge is the source of base flow in most places. 

Bed sediment - The material that temporarily is stationary in 

the bottom of a stream or other watercourse. 

Benthic - Refers to plants or animals that live on the bottom 

of lakes, streams, or oceans. 

Bioaccumulation - The biological sequestering of a substance at a higher concentration than that at which it 

occurs in the surrounding environment or medium. 

Also, the process whereby a substance enters organisms 

through the gills, epithelial tissues, dietary, or other 

sources. 

Biota - Living organisms. 

Breakdown product - A compound derived by chemical, 

biological, or physical action upon a pesticide. The 

breakdown is a natural process which may result in a 

more toxic or a less toxic compound and a more persistent or less persistent compound. 

BTEX - Benzene, toluene, ethylbenzene, and xylene; volatile organic compounds found in gasoline and solvents. 

Chlordane - Octachloro-4,7-methanotetrahydroindane. An 

organochlorine insecticide no longer registered for use 

in the U.S. Technical chlordane is a mixture in which 

the primary components are cis- and trans-chlordane, 

cis- and trans-nonachlor, and heptachlor. 

Community - In ecology, the species that interact in a common area. 

Concentration - The amount or mass of a substance present 

in a given volume or mass of sample. Usually expressed 

as microgram per liter (water sample) or micrograms 

per kilogram (sediment or tissue sample). 

Denitrification - A process by which oxidized forms of 

nitrogen such as nitrate (NO3

-

) are reduced to form 

nitrites, nitrogen oxides, ammonia, or free nitrogen: 

commonly brought about by the action of denitrifying 

bacteria and usually resulting in the escape of nitrogen 

to the air. 

Detect - To determine the presence of a compound. 

DDT - Dichloro-diphenyl-trichloroethane. An organochlorine insecticide no longer registered for use in the 

United States. 

Dieldrin - An organochlorine insecticide no longer registered for use in the United States. Also a degradation 

product of the insecticide aldrin. 

Discharge - Rate of fluid flow passing a given point at a 

given moment in time, expressed as volume per unit of 

time. 

Domestic well - A private home well, or a well that serves 

less than 15 households or 25 individuals. 

Endocrine system - The collection of glands in animals that 

secrete hormones, which influence growth, gender and 

sexual maturity. 

Eutrophication - The process by which water becomes 

enriched with plant nutrients, most commonly phosphorus and nitrogen. 

Ground water - In general, any water that exists beneath the 

land surface, but more commonly applied to water in 

fully saturated soils and geologic formations. 

Herbicide - A chemical or other agent applied for the purpose of killing undesirable plants. See also Pesticide. 

Insecticide - A substance or mixture of substances intended 

to destroy or repel insects. 

Intolerant organisms - Organisms that are not adaptable to 

human alterations to the environment and thus decline 

in numbers where human alterations occur. See also 

Tolerant species. 

Invertebrate - An animal having no backbone or spinal column.

MCL (Maximum Contaminant Level) - Maximum permissible level of a contaminant in water that is delivered to any user of a public water system. MCLs are 

enforceable standards established by the U.S. Environmental Protection Agency. 

Median - The middle or central value in a distribution of 

data ranked in order of magnitude. The median is also 

known as the 50th percentile. 

Metabolite - See breakdown product. 

Monitor well - A well designed for measuring water levels 

and testing ground-water quality. 

Nitrate - An ion consisting of nitrogen and oxygen (NO3

-

). 

Nitrate is a plant nutrient and is very mobile in soils. In 

this report, the term “nitrate” is used as shorthand for 

“nitrate plus nitrite, reported as nitrogen.”

Nutrient - Element or compound essential for animal and 

plant growth. Common nutrients in fertilizer include 

nitrogen, phosphorus, and potassium. 

Organochlorine compound - Synthetic organic compound 

containing chlorine. As generally used, term refers to 

compounds containing mostly or exclusively carbon, 

hydrogen, and chlorine. Examples include organochlorine insecticides, polychlorinated biphenyls, and some 

solvents containing chlorine. 

Pesticide - A chemical applied to crops, rights of way, 

lawns, or residences to control weeds, insects, fungi, 

nematodes, rodents or other “pests.” 

Phosphorus - A nutrient essential for growth that can play a 

key role in stimulating aquatic growth in lakes and 

streams. 

Polychlorinated biphenyls (PCBs) - A mixture of chlorinated derivatives of biphenyl, marketed under the trade 

name Aroclor with a number designating the chlorine 
26 Water Quality in the Lake Erie–Lake Saint Clair Drainages

content (such as Aroclor 1260). PCBs were used in 

transformers and capacitors for insulating purposes and 

in gas pipeline systems as a lubricant. Further sale for 

new use was banned by law in 1979. 

Polycyclic aromatic hydrocarbon (PAH) - A class of 

organic compounds with a fused-ring aromatic structure. PAHs result from incomplete combustion of 

organic carbon (including wood), municipal solid 

waste, and fossil fuels, as well as from natural or 

anthropogenic introduction of uncombusted coal and 

oil. PAHs include benzo[a]pyrene, fluoranthene, and 

pyrene. 

Recharge - Water that infiltrates the ground and reaches the 

saturated zone. 

Runoff - Excess rainwater or snowmelt that is transported to 

streams by overland flow, tile drains, or ground water. 

SMCL (Secondary maximum contaminant level) - Nonenforceable drinking-water standards established by the 

U.S. Environmental Protection Agency for contaminants that may adversely affect the odor or appearance 

of drinking water. 

Sediment - Particles, derived from rocks or biological materials, that have been transported by a fluid or other natural process, suspended or settled in water. 

Semivolatile organic compound (SVOC) - Operationally 

defined as a group of synthetic organic compounds that 

are solvent-extractable and can be determined by gas 

chromatography/mass spectrometry. SVOCs include 

phenols, phthalates, and polycyclic aromatic hydrocarbons (PAHs). 

Streamflow - A type of channel flow, applied to that part of 

surface runoff in a stream whether or not it is affected 

by diversion or regulation. 

Suspended sediment - Particles of rock, sand, soil, and 

organic detritus carried in suspension in the water column, in contrast to sediment that moves on or near the 

streambed. 

Taxon (plural taxa) - Any identifiable group of taxonomically related organisms. 

Tile drain - A buried perforated pipe designed to remove 

excess water from soils. 

Till - An unsorted glacial deposit characterized by low permeability.

Triazine herbicide - A class of herbicides containing a symmetrical triazine ring (a nitrogen-heterocyclic ring composed of three nitrogens and three carbons in an 

alternating sequence). Examples include atrazine, propazine, and simazine. 

Volatile organic compounds (VOCs) - Organic chemicals 

that have a high vapor pressure relative to their water 

solubility. VOCs include components of gasoline, fuel 

oils, and lubricants, as well as organic solvents, fumigants, some inert ingredients in pesticides, and some 

by-products of chlorine disinfection. 

Water table - The point below the land surface where 

ground water is first encountered and below which the 

earth is saturated. Depth to the water table varies widely 

across the country. 

Water year - The continuous 12-month period, October 1 

through September 30, in U.S. Geological Survey 

reports dealing with the surface-water supply. The 

water year is designated by the calendar year in which it 

ends and which includes 9 of the 12 months. Thus, the 

year ending September 30, 1980, is referred to as water 

year 1980. 
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Water-Quality Data in a National Context 29 

APPENDIX—WATER-QUALITY DATA FROM THE LAKE ERIELAKE SAINT CLAIR DRAINAGES IN A NATIONAL CONTEXT

For a complete view of Lake Erie-Lake Saint Clair Drainages data and for additional information about specific benchmarks used, visit our Web site at 

http://water.usgs.gov/nawqa/. Also visit the NAWQA Data Warehouse for access to NAWQA data sets at http://water.usgs.gov/nawqa/data.

Streams in agricultural areas 

Streams in urban areas

Streams and rivers draining mixed land uses 

Shallow ground water in agricultural areas

Shallow ground water in urban areas 

Major aquifers 

Detected concentration in Study Unit

Frequencies of detection, in percent. Detection frequencies 

were not censored at any common reporting limit. The lefthand column is the study-unit frequency and the right-hand 

column is the national frequency 

Not measured or sample size less than two

Study-unit sample size. For ground water, the number of 

samples is equal to the number of wells sampled

National ranges of detected concentrations, by land use, in 36 

NAWQA Study Units, 1991–98—Ranges include only samples

in which a chemical was detected

Drinking-water quality (applies to ground water and surface water)

Protection of aquatic life (applies to surface water only)

Prevention of eutrophication in streams not flowing directly into 

lakes or impoundments

No benchmark for drinking-water quality

No benchmark for protection of aquatic life

*

**

66 38

CHEMICALS IN WATER

Concentrations and detection frequencies, Lake Erie-Lake Saint 

Clair Drainages, 1996–98—Detection sensitivity varies among 

chemicals and, thus, frequencies are not directly comparable among 

chemicals

Lowest

25 percent

Middle

50 percent

Highest

25 percent

National water-quality benchmarks

National benchmarks include standards and guidelines related to 

drinking-water quality, criteria for protecting the health of aquatic life, and 

a goal for preventing stream eutrophication due to phosphorus. Sources 

include the U.S. Environmental Protection Agency and the Canadian 

Council of Ministers of the Environment

|

|

|

--

This appendix is a summary of chemical concentrations 

and biological indicators assessed in the Lake Erie-Lake 

Saint Clair Drainages. Selected results for this Study Unit 

are graphically compared to results from as many as 36 

NAWQA Study Units investigated from 1991 to 1998 and 

to national water-quality benchmarks for human health, 

aquatic life, or fish-eating wildlife. The chemical and 

biological indicators shown were selected on the basis of 

frequent detection, detection at concentrations above a 

national benchmark, or regulatory or scientific importance. 

The graphs illustrate how conditions associated with each 

land use sampled in the Lake Erie-Lake Saint Clair 

Drainages compare to results from across the Nation, and 

how conditions compare among the several land uses. 

Graphs for chemicals show only detected concentrations 

and, thus, care must be taken to evaluate detection 

frequencies in addition to concentrations when comparing 

study-unit and national results. For example, in the Lake 

Erie-Lake Saint Clair Drainages acetochlor concentrations 

in agricultural streams were similar to the national 

distribution, but the detection frequency was much higher 

(61 percent compared to 33 percent). 

CONCENTRATION, IN MICROGRAMS PER LITER

 0.0001 0.001 0.01 0.1 1 10 100 1,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Pesticides in water—Herbicides

Study-unit sample size

12

Acetochlor (Harness Plus, Surpass) * ** 61 33 189 30 9 37 70 38 99

0 <1 30 0 <1 30 0 <1 28

Alachlor (Lasso, Bronco, Lariat, Bullet) **

67 44 | 189 30 20 | 37 76 45 | 99

0 3 | 30 0 <1 | 30 0 1 | 28

Atrazine (AAtrex, Atrex, Atred, Gesaprim) 

100 88 | | 189 100 86 | | 37 100 87 | | 99

3 40 | 30 0 30 | 30 0 18 | 28

Cyanazine (Bladex, Fortrol) 76 44 | | 189 30 14 | | 37 82 54 | | 99

0 1 | 30 0 1 | 30 0 <1 | 28

2,4-D (Aqua-Kleen, Lawn-Keep, Weed-B-Gone) 

37 15 | | 52 31 18 | | 29 27 11 | | 33

0 <1 | 30 0 1 | 29 -- <1 | 0

Deethylatrazine (Atrazine breakdown product) * **

100 75 189 97 62 37 99 75 99

3 39 30 3 28 30 4 19 28

MCPA (Rhomene, Rhonox, Chiptox) 0 1 | | 52 10 4 | | 29 0 1 | | 33

Metolachlor (Dual, Pennant) 

99 81 | | 189 100 64 | | 37 100 83 | | 99

3 18 | 30 0 9 | 30 0 5 | 28

Metribuzin (Lexone, Sencor) 

55 19 | | 189 14 8 | | 37 59 20 | | 99

0 3 | 30 0 2 | 30 0 1 | 28

Prometon (Pramitol, Princep) ** 66 44 | 189 95 86 | 37 92 60 | 99

0 12 | 30 0 21 | 30 0 5 | 28
30 Water Quality in the Lake Erie-Lake Saint Clair Drainages

CONCENTRATION, IN MICROGRAMS PER LITER

 0.0001 0.001 0.01 0.1 1 10 100 1,000 

Other herbicides detected

Acifluorfen (Blazer, Tackle 2S) **

Benfluralin (Balan, Benefin, Bonalan) * **

Bentazon (Basagran, Bentazone) **

Bromoxynil (Buctril, Brominal) * 

Butylate (Sutan +, Genate Plus, Butilate) **

DCPA (Dacthal, chlorthal-dimethyl) * **

Dicamba (Banvel, Dianat, Scotts Proturf) 

2,6-Diethylaniline (Alachlor breakdown product) * **

Diuron (Crisuron, Karmex, Diurex) **

EPTC (Eptam, Farmarox, Alirox) * **

Fenuron (Fenulon, Fenidim) * **

Linuron (Lorox, Linex, Sarclex, Linurex, Afalon) * 

MCPB (Thistrol) * **

Pendimethalin (Pre-M, Prowl, Stomp) * **

Picloram (Grazon, Tordon) 

Propachlor (Ramrod, Satecid) **

Terbacil (Sinbar) **

Triclopyr (Garlon, Grandstand, Redeem, Remedy) * **

Trifluralin (Treflan, Gowan, Tri-4, Trific) 

Herbicides not detected

Bromacil (Hyvar X, Urox B, Bromax) 

Chloramben (Amiben, Amilon-WP, Vegiben) **

Clopyralid (Stinger, Lontrel, Transline) * **

2,4-DB (Butyrac, Butoxone, Embutox Plus, Embutone) * **

Dacthal mono-acid (Dacthal breakdown product) * **

Dichlorprop (2,4-DP, Seritox 50, Lentemul) * **

Dinoseb (Dinosebe) 

Ethalfluralin (Sonalan, Curbit) * **

Fluometuron (Flo-Met, Cotoran) **

Molinate (Ordram) * **

Napropamide (Devrinol) * **

Neburon (Neburea, Neburyl, Noruben) * **

Norflurazon (Evital, Predict, Solicam, Zorial) * **

Oryzalin (Surflan, Dirimal) * **

Pebulate (Tillam, PEBC) * **

Pronamide (Kerb, Propyzamid) **

Propanil (Stam, Stampede, Wham) * **

Propham (Tuberite) **

2,4,5-T **

2,4,5-TP (Silvex, Fenoprop) **

Thiobencarb (Bolero, Saturn, Benthiocarb) * **

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Pesticides in water—Insecticides

Study-unit sample size

CONCENTRATION, IN MICROGRAMS PER LITER

 0.0001 0.001 0.01 0.1 1 10 100 1,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent Study-unit sample size

Volatile organic compounds (VOCs) in ground water

These graphs represent data from 16 Study Units, sampled from 1996 to 1998

Study-unit frequency of detection, in percent

National frequency of detection in percent Study-unit sample size

CONCENTRATION, IN MICROGRAMS PER LITER

 0.001 0.01 0.1 1 10 100 1,000 10,000 

Other insecticides detected 

Carbofuran (Furadan, Curaterr, Yaltox) 

Dieldrin (Panoram D-31, Octalox, Compound 497) 

Fonofos (Dyfonate, Capfos, Cudgel, Tycap) **

alpha-HCH (alpha-BHC, alpha-lindane) **

Malathion (Malathion) 

Methyl parathion (Penncap-M, Folidol-M) **

Insecticides not detected

Aldicarb (Temik, Ambush, Pounce) 

Aldicarb sulfone (Standak, aldoxycarb) 

Aldicarb sulfoxide (Aldicarb breakdown product) 

Azinphos-methyl (Guthion, Gusathion M) * 

Disulfoton (Disyston, Di-Syston) **

Ethoprop (Mocap, Ethoprophos) * **

gamma-HCH (Lindane, gamma-BHC) 

3-Hydroxycarbofuran (Carbofuran breakdown product) * **

Methiocarb (Slug-Geta, Grandslam, Mesurol) * **

Methomyl (Lanox, Lannate, Acinate) **

Oxamyl (Vydate L, Pratt) **

Parathion (Roethyl-P, Alkron, Panthion, Phoskil) * 

cis-Permethrin (Ambush, Astro, Pounce) * **

Phorate (Thimet, Granutox, Geomet, Rampart) * **

Propargite (Comite, Omite, Ornamite) * **

Propoxur (Baygon, Blattanex, Unden, Proprotox) * **

Terbufos (Contraven, Counter, Pilarfox) **

Simazine (Princep, Caliber 90) 

95 61 | | 189 97 77 | | 37 91 74 | | 99

0 21 | 30 3 18 | 30 0 5 | 28

Tebuthiuron (Spike, Tebusan) 

16 22 | | 189 8 39 | | 37 52 32 | | 99

0 3 | 30 0 7 | 30 0 3 | 28

CONCENTRATION, IN MICROGRAMS PER LITER

 0.0001 0.001 0.01 0.1 1 10 100 1,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent Study-unit sample size

Carbaryl (Carbamine, Denapon, Sevin) 

7 9 | | 189 35 46 | | 37 27 16 | | 99

0 <1 | 30 0 2 | 30 0 1 | 28

Chlorpyrifos (Brodan, Dursban, Lorsban) 13 18 | | 186 19 37 | | 37 36 20 | | 97

0 1 | 30 0 1 | 30 0 <1 | 28

p,p'-DDE 

2 8 | | 189 0 2 | | 37 0 4 | | 99

0 4 | 30 0 2 | 30 0 2 | 28

Diazinon (Basudin, Diazatol, Neocidol, Knox Out) 23 16 | | 189 68 70 | | 37 70 39 | | 99

0 <1 | 30 0 2 | 30 4 2 | 28

Carbon disulfide * 

-- 30 0 53 42 30 25 24 28

1,3 & 1,4-Dimethylbenzene (m-&p-Xylene) 

-- 7 | 0 53 18 | 30 18 3 | 28
Water-Quality Data in a National Context 31 

CONCENTRATION, IN MILLIGRAMS PER LITER

 0.001 0.01 0.1 1 10 100 1,000 10,000 100,000 

CONCENTRATION, IN MILLIGRAMS PER LITER

 0.001 0.01 0.1 1 10 100 1,000 10,000 100,000 

Nutrients in water

Study-unit frequency of detection, in percent

National frequency of detection, in percent Study-unit sample size

Dissolved solids in water

Study-unit frequency of detection, in percent

National frequency of detection, in percent Study-unit sample size

Study-unit frequency of detection, in percent

National frequency of detection in percent Study-unit sample size

CONCENTRATION, IN MICROGRAMS PER LITER

 0.001 0.01 0.1 1 10 100 1,000 10,000 

Methylbenzene (Toluene) 

-- 36 | 0 77 30 | 30 4 11 | 28

Other VOCs detected

Benzene 

Bromodichloromethane (Dichlorobromomethane) 

2-Butanone (Methyl ethyl ketone (MEK)) * 

Chlorodibromomethane (Dibromochloromethane) 

1,4-Dichlorobenzene (p-Dichlorobenzene) 

Dichlorodifluoromethane (CFC 12, Freon 12) 

Dichloromethane (Methylene chloride) 

1,2-Dimethylbenzene (o-Xylene) 

1-4-Epoxy butane (Tetrahydrofuran, Diethylene oxide) * 

Ethenylbenzene (Styrene) 

Ethylbenzene (Phenylethane) 

Iodomethane (Methyl iodide) * 

2-Propanone (Acetone) * 

Tetrachloroethene (Perchloroethene) 

1,1,1-Trichloroethane (Methylchloroform) 

Trichloromethane (Chloroform) 

1,2,4-Trimethylbenzene (Pseudocumene) * 

VOCs not detected

tert-Amylmethylether (tert-amyl methyl ether (TAME)) * 

Bromobenzene (Phenyl bromide) * 

Bromochloromethane (Methylene chlorobromide) 

Bromoethene (Vinyl bromide) * 

Bromomethane (Methyl bromide) 

n-Butylbenzene (1-Phenylbutane) * 

sec-Butylbenzene * 

tert-Butylbenzene * 

3-Chloro-1-propene (3-Chloropropene) * 

1-Chloro-2-methylbenzene (o-Chlorotoluene) 

1-Chloro-4-methylbenzene (p-Chlorotoluene) 

Chlorobenzene (Monochlorobenzene) 

Chloroethane (Ethyl chloride) * 

Chloroethene (Vinyl chloride) 

Chloromethane (Methyl chloride) 

1,2-Dibromo-3-chloropropane (DBCP, Nemagon) 

1,2-Dibromoethane (Ethylene dibromide, EDB) 

Dibromomethane (Methylene dibromide) * 

trans-1,4-Dichloro-2-butene ((Z)-1,4-Dichloro-2-butene) * 

1,2-Dichlorobenzene (o-Dichlorobenzene) 

1,3-Dichlorobenzene (m-Dichlorobenzene) 

1,2-Dichloroethane (Ethylene dichloride) 

1,1-Dichloroethane (Ethylidene dichloride) * 

1,1-Dichloroethene (Vinylidene chloride) 

trans-1,2-Dichloroethene ((E)-1,2-Dichlorothene) 

cis-1,2-Dichloroethene ((Z)-1,2-Dichloroethene) 

1,2-Dichloropropane (Propylene dichloride) 

2,2-Dichloropropane * 

1,3-Dichloropropane (Trimethylene dichloride) * 

trans-1,3-Dichloropropene ((E)-1,3-Dichloropropene) 

cis-1,3-Dichloropropene ((Z)-1,3-Dichloropropene) 

1,1-Dichloropropene * 

Diethyl ether (Ethyl ether) * 

Diisopropyl ether (Diisopropylether (DIPE)) * 

Ethyl methacrylate * 

Ethyl tert-butyl ether (Ethyl-t-butyl ether (ETBE)) * 

1-Ethyl-2-methylbenzene (2-Ethyltoluene) * 

Hexachlorobutadiene 

1,1,1,2,2,2-Hexachloroethane (Hexachloroethane) 

2-Hexanone (Methyl butyl ketone (MBK)) * 

Isopropylbenzene (Cumene) * 

p-Isopropyltoluene (p-Cymene) * 

Methyl acrylonitrile * 

Methyl tert-butyl ether (MTBE) 

Methyl-2-methacrylate (Methyl methacrylate) * 

4-Methyl-2-pentanone (Methyl isobutyl ketone (MIBK)) * 

Methyl-2-propenoate (Methyl acrylate) * 

Naphthalene 

2-Propenenitrile (Acrylonitrile) 

n-Propylbenzene (Isocumene) * 

1,1,2,2-Tetrachloroethane * 

1,1,1,2-Tetrachloroethane 

Tetrachloromethane (Carbon tetrachloride) 

1,2,3,4-Tetramethylbenzene (Prehnitene) * 

1,2,3,5-Tetramethylbenzene (Isodurene) * 

Tribromomethane (Bromoform) 

1,1,2-Trichloro-1,2,2-trifluoroethane (Freon 113) * 

1,2,4-Trichlorobenzene 

1,2,3-Trichlorobenzene * 

1,1,2-Trichloroethane (Vinyl trichloride) 

Trichloroethene (TCE) 

Trichlorofluoromethane (CFC 11, Freon 11) 

1,2,3-Trichloropropane (Allyl trichloride) 

1,2,3-Trimethylbenzene (Hemimellitene) * 

1,3,5-Trimethylbenzene (Mesitylene) * 

Ammonia, as N * **

71 84 219 93 86 43 83 75 115

97 78 30 80 71 30 100 70 28

Dissolved ammonia plus organic nitrogen, as N * ** 90 78 219 100 74 43 100 62 115

77 28 30 13 30 30 82 24 28

Dissolved nitrite plus nitrate, as N ** 99 95 | 219 100 97 | 43 100 91 | 115

67 81 | 30 73 74 | 30 11 71 | 28

Orthophosphate, as P * **

69 79 219 65 72 43 90 74 115

57 59 30 17 52 30 68 61 28

Total phosphorus, as P * ** 87 92 | 217 93 90 | 43 100 88 | 115

Dissolved solids * ** 100 100 215 100 100 43 100 100 115

100 100 30 100 100 30 100 100 28
32 Water Quality in the Lake Erie-Lake Saint Clair Drainages

Fish tissue from streams in agricultural areas

Fish tissue from streams in urban areas

Fish tissue from streams draining mixed land uses

Sediment from streams in agricultural areas 

Sediment from streams in urban areas 

Sediment from streams draining mixed land uses

Protection of fish-eating wildlife (applies to fish tissue)

Protection of aquatic life (applies to bed sediment)

No benchmark for protection of fish-eating wildlife

No benchmark for protection of aquatic life

|

|

**

CHEMICALS IN FISH TISSUE

AND BED SEDIMENT

Concentrations and detection frequencies, Lake Erie-Lake Saint 

Clair Drainages, 1996–98—Detection sensitivity varies among 

chemicals and, thus, frequencies are not directly comparable among 

chemicals. Study-unit frequencies of detection are based on small 

sample sizes; the applicable sample size is specified in each graph

Lowest

25 percent

Middle

50 percent

Highest

25 percent

National benchmarks for fish tissue and bed sediment

National benchmarks include standards and guidelines related to 

criteria for protection of the health of fish-eating wildlife and aquatic 

organisms. Sources include the U.S. Environmental Protection Agency, 

other Federal and State agencies, and the Canadian Council of 

Ministers of the Environment

*

CONCENTRATION, IN MICROGRAMS PER KILOGRAM

(Fish tissue is wet weight; bed sediment is dry weight)

 0.1 1 10 100 1,000 10,000 100,000 

CONCENTRATION, IN MICROGRAMS PER KILOGRAM

(Fish tissue is wet weight; bed sediment is dry weight)

 0.1 1 10 100 1,000 10,000 100,000 

National ranges of concentrations detected, by land use, in 36 

NAWQA Study Units, 1991–98—Ranges include only samples

in which a chemical was detected

Detected concentration in Study Unit

Frequencies of detection, in percent. Detection frequencies 

were not censored at any common reporting limit. The lefthand column is the study-unit frequency and the right-hand 

column is the national frequency

Not measured or sample size less than two

Study-unit sample size

66 38

--

12

Organochlorines in fish tissue (whole body)

and bed sediment

Study-unit frequency of detection, in percent

National frequency of detection, in percent Study-unit sample size

Study-unit frequency of detection, in percent

National frequency of detection, in percent Study-unit sample size

Other trace elements detected

Lead 

Selenium 

Uranium 

Zinc

Trace elements not detected

Cadmium 

CONCENTRATION, IN PICOCURIES PER LITER

Trace elements in ground water

Study-unit frequency of detection, in percent

National frequency of detection, in percent Study-unit sample size

Arsenic 

-- 58 | 0 23 36 | 30 -- 37 | 0

Chromium 

-- 85 | 0 100 79 | 29 -- 73 | 0

Radon-222 

-- 99 | 0 100 100 | 21 100 97 | 28

CONCENTRATION, IN MICROGRAMS PER LITER

 0.01 0.1 1 10 100 1,000 10,000 100,000 

 0.01 0.1 1 10 100 1,000 10,000 100,000 

Total Chlordane (sum of 5 chlordanes) 

38 38 | 8 100 75 | 2 80 56 | 5

0 9 | 7 40 57 | 5 33 11 | 3

o,p'+p,p'-DDD (sum of o,p'-DDD and p,p'-DDD) * 

38 49 8 100 69 2 80 50 5

29 27 | 7 80 50 | 5 100 20 | 3

p,p'-DDE * ** 88 90 8 100 94 2 100 92 5

43 48 7 80 62 5 67 39 3

o,p'+p,p'-DDE (sum of o,p'-DDE and p,p'-DDE) * 88 90 8 100 94 2 100 92 5

43 48 | 7 80 62 | 5 67 39 | 3

o,p'+p,p'-DDT (sum of o,p'-DDT and p,p'-DDT) * 

0 31 8 100 53 2 0 29 5

0 19 | 7 40 38 | 5 33 11 | 3

Total DDT (sum of 6 DDTs) **

88 90 | 8 100 94 | 2 100 93 | 5

43 49 7 80 66 5 100 41 3

Dieldrin (Panoram D-31, Octalox) * 

43 53 7 0 42 2 80 38 5

29 13 | 7 0 30 | 5 67 9 | 3
Water-Quality Data in a National Context 33 

CONCENTRATION, IN MICROGRAMS PER KILOGRAM, DRY WEIGHT

 0.1 1 10 100 1,000 10,000 100,000 

CONCENTRATION, IN MICROGRAMS PER KILOGRAM, DRY WEIGHT

 0.1 1 10 100 1,000 10,000 100,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Semivolatile organic compounds (SVOCs)

in bed sediment

Study-unit sample size

Study-unit sample size

Other organochlorines detected

Heptachlor epoxide (Heptachlor breakdown product) * 

Heptachlor+heptachlor epoxide (sum of heptachlor and heptachlor epoxide) **

Pentachloroanisole (PCA) * **

Organochlorines not detected

Chloroneb (Chloronebe, Demosan) * **

DCPA (Dacthal, chlorthal-dimethyl) * **

Endosulfan I (alpha-Endosulfan, Thiodan) * **

Endrin (Endrine) 

gamma-HCH (Lindane, gamma-BHC, Gammexane) * 

Total-HCH (sum of alpha-HCH, beta-HCH, gamma-HCH, and delta-HCH) **

Isodrin (Isodrine, Compound 711) * **

p,p'-Methoxychlor (Marlate, methoxychlore) * **

o,p'-Methoxychlor * **

Mirex (Dechlorane) **

cis-Permethrin (Ambush, Astro, Pounce) * **

trans-Permethrin (Ambush, Astro, Pounce) * **

Toxaphene (Camphechlor, Hercules 3956) * **

1 The national detection frequencies for total PCB in sediment are biased low because about 

30 percent of samples nationally had elevated detection levels compared to this Study Unit. 

See http://water.usgs.gov/nawqa/ for additional information.

CONCENTRATION, IN MICROGRAMS PER KILOGRAM

(Fish tissue is wet weight; bed sediment is dry weight)

 0.1 1 10 100 1,000 10,000 100,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent Study-unit sample size

Dieldrin+aldrin (sum of dieldrin and aldrin) ** 38 52 | 8 0 42 | 2 80 38 | 5

29 13 7 0 29 5 67 9 3

Hexachlorobenzene (HCB) ** 25 8 | 8 50 12 | 2 0 3 | 5

0 4 7 0 4 4 0 1 2

Total PCB 1

50 38 | 8 100 81 | 2 100 66 | 5

0 2 | 7 60 21 | 5 67 9 | 3

Acenaphthene 

14 10 | 7 60 54 | 5 100 27 | 3

Anthracene 

86 37 | 7 100 89 | 5 100 56 | 3

Anthraquinone **

71 21 7 80 83 5 100 39 3

Benz[a]anthracene 

100 44 | 7 100 94 | 5 100 62 | 3

Benzo[a]pyrene 

86 40 | 7 100 92 | 5 100 59 | 3

9H-Carbazole **

29 19 7 100 76 5 100 33 3

Chrysene 

100 50 | 7 100 94 | 5 100 67 | 3

Dibenz[a,h]anthracene 

57 8 | 7 60 68 | 5 33 23 | 3

Dibenzothiophene **

29 12 7 60 64 5 100 30 3

1,4-Dichlorobenzene (p-Dichlorobenzene) **

20 6 5 67 7 3

2,6-Dimethylnaphthalene **

100 65 7 100 74 5 100 77 3

bis(2-Ethylhexyl)phthalate **

100 91 7 100 99 5 100 95 3

Fluoranthene 

100 66 | 7 100 97 | 5 100 78 | 3
34 Water Quality in the Lake Erie-Lake Saint Clair Drainages

CONCENTRATION, IN MICROGRAMS PER GRAM

(Fish tissue is wet weight, bed sediment is dry weight)

 0.01 0.1 1 10 100 10,000 1,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Trace elements in fish tissue (livers) and 

bed sediment

Study-unit sample size

CONCENTRATION, IN MICROGRAMS PER KILOGRAM, DRY WEIGHT

 0.1 1 10 100 1,000 10,000 100,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Other SVOCs detected

Acenaphthylene 

Acridine **

Benzo[b]fluoranthene **

Benzo[c]cinnoline **

Benzo[ghi]perylene **

Benzo[k]fluoranthene **

2,2-Biquinoline **

Butylbenzylphthalate **

p-Cresol **

Di-n-butylphthalate **

Di-n-octylphthalate **

Diethylphthalate **

1,2-Dimethylnaphthalene **

1,6-Dimethylnaphthalene **

3,5-Dimethylphenol **

Dimethylphthalate **

2-Ethylnaphthalene **

9H-Fluorene (Fluorene) 

Indeno[1,2,3-cd]pyrene **

Isophorone **

Isoquinoline **

1-Methyl-9H-fluorene **

2-Methylanthracene **

4,5-Methylenephenanthrene **

1-Methylphenanthrene **

1-Methylpyrene **

Naphthalene 

Phenanthridine **

2,3,6-Trimethylnaphthalene **

SVOCs not detected

C8-Alkylphenol **

Azobenzene **

4-Bromophenyl-phenylether **

4-Chloro-3-methylphenol **

bis(2-Chloroethoxy)methane **

2-Chloronaphthalene **

2-Chlorophenol **

4-Chlorophenyl-phenylether **

1,2-Dichlorobenzene (o-Dichlorobenzene) **

1,3-Dichlorobenzene (m-Dichlorobenzene) **

2,4-Dinitrotoluene **

Nitrobenzene **

N-Nitrosodi-n-propylamine **

Pentachloronitrobenzene **

Quinoline **

1,2,4-Trichlorobenzene **

Study-unit sample size

N-Nitrosodiphenylamine **

14 2 7 0 10 5 0 4 3

Phenanthrene 

100 50 | 7 100 93 | 5 100 66 | 3

Phenol **

86 81 7 100 82 5 100 80 3

Pyrene 

100 64 | 7 100 95 | 5 100 76 | 3

Arsenic * 

86 56 7 100 38 2 100 76 4

100 99 | 7 100 98 | 5 100 97 | 3

Cadmium * 

100 77 7 100 72 2 100 95 4

100 98 | 7 100 100 | 5 100 98 | 3

Chromium * 43 62 7 0 72 2 25 54 4

100 100 | 7 100 99 | 5 100 100 | 3

Copper * 100 100 7 100 100 2 100 100 4

100 100 | 7 100 99 | 5 100 100 | 3

Lead * 

0 11 7 100 41 2 100 41 4

100 100 | 7 100 100 | 5 100 99 | 3

Mercury * 

100 71 7 100 59 2 100 80 4

100 82 | 7 100 97 | 5 100 93 | 3

Nickel * **

0 42 7 50 44 2 0 50 4

100 100 7 100 100 5 100 100 3

Selenium * 100 99 7 100 100 2 100 99 4

100 100 | 7 100 100 | 5 100 100 | 3

Zinc * 

100 100 7 100 100 2 100 100 4

100 100 | 7 100 99 | 5 100 100 | 3
Water-Quality Data in a National Context 35 

Biological indicator value, Lake Erie - Lake Saint Clair 

Drainages, by land use, 1996–98

Biological status assessed at a site

National ranges of biological indicators, in 16 NAWQA Study 

Units, 1994–98

Streams in undeveloped areas

Streams in agricultural areas

Streams in urban areas

Streams in mixed-land-use areas

75th percentile

25th percentile

BIOLOGICAL INDICATORS

Higher national scores suggest habitat disturbance, water-quality 

degradation, or naturally harsh conditions. The status of algae, 

invertebrates (insects, worms, and clams), and fish provide a 

record of water-quality and stream conditions that waterchemistry indicators may not reveal. Algal status focuses on the 

changes in the percentage of certain algae in response to 

increasing siltation, and it often correlates with higher nutrient 

concentrations in some regions. Invertebrate status averages 11 

metrics that summarize changes in richness, tolerance, trophic 

conditions, and dominance associated with water-quality 

degradation. Fish status sums the scores of four fish metrics 

(percent tolerant, omnivorous, non-native individuals, and percent 

individuals with external anomalies) that increase in association 

with water-quality degradation

 0 10 20 30 40 50 60 70 80 90 100

 0 5 10 15 20

 Algal status indicator

Undeveloped

Agricultural

Urban

Mixed

 Invertebrate status indicator

Undeveloped

Agricultural

Urban

Mixed

 Fish status indicator

Undeveloped

Agricultural

Urban

Mixed
A COORDINATED EFFORT

Coordination with agencies and organizations in the Lake Erie-Lake Saint Clair Drainages was integral to the 

success of this water-quality assessment. We thank those who served as members of our liaison committee. 

Federal Agencies

U.S. Environmental Protection Agency

U.S. Army Corps of Engineers

U.S. Department of Agriculture

Environment Canada, Great Lakes Division

State Agencies

Ohio Environmental Protection Agency

Ohio Department of Natural Resources

Ohio Lake Erie Commission

Michigan Department of Agriculture

Michigan Department of Environmental Quality

Indiana Department of Natural Resources

New York Department of Environmental Conservation

Local Agencies

City of Fort Wayne

City of Toledo

Southeast Michigan Council of Governments

Washtenaw County, Michigan, Health Department

Oakland County, Michigan, Health Department

Allen County, Indiana, Soil and Water Conservation 

District

Other public and private organizations

Rouge River Program Office, Michigan

The Nature Conservancy

Great Lakes Commission

International Association of Great Lakes Researchers

Michigan State University

University of Michigan, Dearborn

We thank the following individuals for contributing to this effort.

Robert Pigg, Michigan Department of Agriculture

John Estenik, Ohio Environmental Protection Agency

Charles Staudt, Ohio Environmental Protection Agency

Terry Keiser, Ohio Northern University

Special thanks to U.S. Geological Survey employees for their contributions:

 Kevin Metzker, lead technician, Erin Lynch, Bill Yost, Dennis Finnegan, Stephanie Brubeck, Alex Covert,

Rick Hubbell, Craig Oberst, David Eckhardt, George Casey, and Michael Wieczorek. Richard Frehs and 

C. Michael Eberle for production of the report, including editing, layout, and illustrations. 

Appreciation also is extended to those individuals and agencies that reviewed this report: Mark Ayers, Charles

Peters, and Patrick Phillips, and others at the U.S. Geological Survey; Tom Crane, Great Lakes Commission, 

and Jeffrey Busch, Ohio Lake Erie Commission.
Myers and others—Water Quality in the Lake Erie-Lake Saint Clair Drainages

U.S. Geological Survey Circular 1203

National Water-Quality Assessment (NAWQA) Program

Lake Erie-Lake Saint Clair Drainages

NAWQA

St. Clair R

Clinton R LAKE

ST.

CLAIR

LAKE ERIE

Sandusky R

Maumee R

Cuyahoga R.

Nai gara R

Huron R

R Rouge Detroit

River

Erie Ann

Arbor

Lima

Toledo Cleveland

Akron

Ft.

Wayne

Buffalo

Detroit

U.S.

PA CANADA

MI

IN OHIO

NY