Occurrence, Distribution, and Loads of

Selected Pesticides in Streams in the

Lake Erie-Lake St. Clair Basin, 1996–98

By Jeffrey W. Frey

Water-Resources Investigations Report 00-4169

National Water-Quality Assessment Program

Indianapolis, Indiana

2001

U.S. Department of the Interior

U.S. Geological Survey
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, SECRETARY

U.S. GEOLOGICAL SURVEY

CHARLES G. GROAT, Director

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

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

For additional information, write to:

District Chief

U.S. Geological Survey

5957 Lakeside Boulevard

Indianapolis, IN 46278-1996

Copies of this report can be purchased from:

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Federal Center

Denver, CO 80225-0286

Information regarding the National Water-Quality Assessment (NAWQA) Program

is available on the Internet via the World Wide Web. You can connect to the

NAWQA Home Page using the Universal Resource Locator (URL) at:

<URL:http://water.usgs.gov/nawqa>
Foreword

The U.S. Geological Survey (USGS) is committed

to serve the Nation with accurate and timely scientific information that helps enhance and protect

the overall quality of life, and facilitates effective

management of water, biological, energy, and

mineral resources. Information on the quality of

the Nation’s water resources is of critical interest

to the USGS because it is so integrally linked to

the long-term availability of water that is clean

and safe for drinking and recreation and that is

suitable for industry, irrigation, and habitat for

fish and wildlife. Escalating population growth

and increasing demands for the multiple water uses

make water availability, now measured in terms

of quantity and quality, even more critical to the

long-term sustainability of our communities and

ecosystems.

The USGS implemented the National WaterQuality Assessment (NAWQA) Program to

support national, regional, and local information

needs and decisions related to water-quality management and policy. Shaped by and coordinated

with ongoing efforts of other Federal, State, and

local agencies, the NAWQA Program is designed

to answer: What is the condition of our Nation’s

streams and ground water? How are the conditions

changing over time? How do natural features

and human activities affect the quality of streams

and ground water, and where are those effects most

pronounced? By combining information on water

chemistry, physical characteristics, stream habitat,

and aquatic life, the NAWQA Program aims to

provide science-based insights for current and

emerging water issues. NAWQA results can contribute to informed decisions that result in practical

and effective water-resource management and

strategies that protect and restore water quality.

Since 1991, the NAWQA Program has implemented interdisciplinary assessments in more than

50 of the Nation’s most important river basins and

aquifers, referred to as Study Units. Collectively,

these Study Units account for more than 60 percent

of the overall water use and population served by

public water supply, and are representative of

the Nation’s major hydrologic landscapes, priority

ecological resources, and agricultural, urban, and

natural sources of contamination.

Each assessment is guided by a nationally consistent study design and methods of sampling and

analysis. The assessments thereby build local

knowledge about water-quality issues and trends

in a particular stream or aquifer while providing

an understanding of how and why water quality

varies regionally and nationally. The consistent,

multi-scale approach helps to determine if certain types of water-quality issues are isolated

or pervasive, and allows direct comparisons of

how human activities and natural processes affect

water quality and ecological health in the Nation’s

diverse geographic and environmental settings.

Comprehensive assessments on pesticides, nutrients, volatile organic compounds, trace metals,

and aquatic ecology are developed at the national

scale through comparative analysis of the StudyUnit findings.

The USGS places high value on the communication and dissemination of credible, timely, and

relevant science so that the most recent and available knowledge about water resources can be

applied in management and policy decisions. We

hope this NAWQA publication will provide you

the needed insights and information to meet your

needs, and thereby foster increased awareness

and involvement in the protection and restoration

of our Nation’s waters.

The NAWQA Program recognizes that a national

assessment by a single program cannot address all

water-resource issues of interest. External coordination at all levels is critical for a fully integrated

understanding of watersheds and for cost-effective

management, regulation, and conservation of our

Nation’s water resources. The Program, therefore,

depends extensively on the advice, cooperation,

and information from other Federal, State, interstate, Tribal, and local agencies, non-government

organizations, industry, academia, and other stakeholder groups. The assistance and suggestions of

all are greatly appreciated.

Robert M. Hirsch

Chief Hydrologist

Contents

Contents v

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

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

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

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Description of the Lake Erie-Lake St.Clair Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Location and Hydrologic Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Physiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Geology and Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Climate and Hydrologic Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Land and Water Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Pesticide Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Sampling-Site Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Analytical and Sampling Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Field Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Laboratory Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Quality-Assurance Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Computation of Pesticide Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Occurrence, Distribution, and Loads of Selected Pesticides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Pesticide Detections and Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Spatial Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Temporal Variations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Degradates of Selected Herbicides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Relation to Drinking-Water Standards or Guidelines and Aquatic-Life Guidelines . . . . . . . . . . . 27

Loads and Yields of Selected Pesticides in Streams of Lake Erie . . . . . . . . . . . . . . . . . . . . . . . . . 35

Relation of Pesticide Occurrence to Pesticide Properties, Pesticide Use, and Environmental

 Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Pesticide Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Pesticide Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Environmental Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Appendix A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Field Blanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Field Spikes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Split Replicates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Appendix B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Contents—Continued

vi Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Figures

1–2. Maps showing:

1. Location and surface-water-sampling sites of the Lake Erie-Lake St. Clair Basin . . . . . . . . . . . . . . . 4

2. Infiltration rates of soils in the Lake Erie-Lake St. Clair Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3. Graphs showing percentage of mean monthly precipitation, percentage of mean monthly streamflow,

and streamflow from March 1996 to February 1998 at three surface-water-sampling sites in the western

part of the Lake Erie-Lake St. Clair Basin and one site in the eastern part of the Basin . . . . . . . . . . . . . . 7

4. Map showing land use in the Lake Erie-Lake St. Clair Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

5–20. Graphs showing:

5. Amount of agricultural-use herbicides and insecticides applied in 1995 in the Lake Erie-Lake

St. Clair Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

6. Percentage of samples collected for each hydrologic condition at 10 surface-water-sampling sites,

Lake Erie-Lake St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

7. Seasonal relation of atrazine load to streamflow, St. Joseph River near Newville, Ind., 1996–98 . . . 18

8. Number of pesticides detected in the Lake Erie-Lake St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . 19

9. Relation of frequency of detections for selected pesticides to primary land use in the Lake ErieLake St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

10. Concentrations of atrazine and diazinon in streams in pasture/forest, row-crop, and urban areas,

Lake Erie-Lake St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

11. Relation of cyanazine and diazinon concentrations to time for samples collected in streams in

an urban area and in a row-crop area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

12. Atrazine concentrations in the Lake Erie-Lake St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . . . . . . 25

13. Relation of selected pesticide concentrations and streamflow to time . . . . . . . . . . . . . . . . . . . . . . . . . 26

14. Relation of the triazine compound atrazine, the acetanilide alachlor, and selected degradate

concentrations and streamflow to time in the St. Joseph River near Newville, Ind. . . . . . . . . . . . . . . 28

15. Number of times U.S. Environmental Protection Agency aquatic-life guidelines were exceeded,

by site, in the Lake Erie-Lake St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

16. Relation of frequency of pesticide detection to pesticide application for all surface-water-sampling

sites by runoff potential and pesticide family, Lake Erie-Lake St. Clair Basin, 1996–98 . . . . . . . . . . 41

17. Atrazine application in 1997 and concentrations, by site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

18. Relation of alachlor and acetochlor concentrations and streamflow to time in the St. Joseph River

near Newville, Ind., and alachlor and acetochlor application in Indiana, 1991–98 . . . . . . . . . . . . . . . 43

19. Relation of atrazine concentrations and streamflow to time in the St. Joseph River near Newville,

Ind., March 1996–September 1998 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

20. Percentage of applied atrazine exported to streams in row-crop basins and the percentage of

permeable soils in each study basin of the Lake Erie-Lake St. Clair Basin, 1996–98 . . . . . . . . . . . . . 45

Appendix Figure

A1. Graph showing percent differences and differences in concentration between the 10 environmental

and split-replicate samples for the Lake Erie-Lake St. Clair study, 1996–98 . . . . . . . . . . . . . . . . . . . . 58
Contents—Continued

Contents vii

Tables

1. National Weather Service precipitation stations used to compute 30-year normals for four surfacewater-sampling sites in the Lake Erie-Lake St. Clair Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2. Drainage area, land use, percent permeable soils, and base-flow index for surface-water-sampling

sites in the Lake Erie-Lake St. Clair Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3. Characteristics of compounds analyzed and their use in the Lake Erie-Lake St. Clair Basin study

area in 1995. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4. Frequency of detection and summary of pesticide concentrations for evaluated pesticides in the

Lake Erie-Lake St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5. Human-health and aquatic-life benchmarks established for evaluated compounds . . . . . . . . . . . . . . . . 30

6. Two-year time-weighted average concentrations and time-weighted May through July average

concentrations for selected pesticides at 10 surface-water-sampling sites in the Lake Erie-Lake

St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

7. Estimated pesticide application in 1997 and summary of loads and yields calculated March 1996 to

February 1998 per drainage area of selected pesticides in Lake Erie-Lake St. Clair Basin surfacewater-sampling sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

8. Drainage area, estimated atrazine application in 1997, atrazine load, and percentage of applied

atrazine exported at Lake Erie-Lake St. Clair Basin surface-water-sampling sites, 1996–98 . . . . . . . . 39

Appendix Tables

A1. Bias and variability estimates for 7 field blanks and 10 split-replicate samples, Lake Erie-Lake

St. Clair Basin, 1996–98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

A2. Precision and bias estimates for pesticides in 7 field spikes from the Lake Erie-Lake St. Clair Basin,

March 1996–February 1998, and 751 to 754 laboratory spikes for all National Water-Quality

Assessment Program Study Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

B1–B10. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the

median, 95th percentile, and maximum concentrations for samples from the:

B1. River Raisin near Manchester, Mich. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

B2. Clinton River at Sterling Heights, Mich. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

B3. Auglaize River near Fort Jennings, Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

B4. Cattaraugus Creek at Gowanda, N.Y. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

B5. Black River near Jeddo, Mich. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

B6. Grand River at Harpersfield, Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

B7. St. Joseph River near Newville, Ind. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

B8. Cuyahoga River at Cleveland, Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

B9. Maumee River at New Haven, Ind. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

B10. Maumee River at Waterville, Ohio. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
viii Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Conversion Factors, Vertical Datum, and Abbreviations

Multiply By To obtain

inch (in.) 25.4 millimeter

inch per year (in/yr) 25.4 millimeter per year

foot (ft) 0.3048 meter

square foot (ft2) 0.09290 square meter

mile (mi) 1.609 kilometer

square mile (mi2) 2.590 square kilometer

gallon (gal) 3.785 liter

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

pound per day (lb/d) 0.4536 kilogram per day

Temperature is given in degrees Celsius (°C), which can be converted to degrees Fahrenheit (°F) as follows:

°F = 1.8 x °C + 32

Vertical Datum: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)—a geodetic

datum derived from a general adjustment of the first-order level nets of the United States and Canada, formerly called Sea Level

Datum of 1929.

The following abbreviations and acronyms are used in this report:

a.i. active ingredient

Koc organic-carbon-normalized adsorption coefficient

ESA ethane sulfonic acid

GC/MS gas chromatography/mass spectrometry

HA-L health advisory lifetime value

HPLC high performance liquid chromatography

IBI Index of Biological Integrity

IJC International Joint Commission

LC/MS liquid chromatography/mass spectrometry

MCL Maximum Contaminant Level

MCPP 2-(4-chloro-2-methylphenoxy)-propanoic acid, potassium salt

MDL method detection limit

MRLC Multi-Resolution Land Characteristics

MS mass spectrometry

NAWQA National Water-Quality Assessment Program

NWQL National Water Quality Laboratory

QHEI Qualitative Habitat Evaluation Index

RSD risk-specific dosage

SPE solid phase extraction

STATSGO State Soil Geographic Data Base

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

L liter

mL milliliter

mg/L milligram per liter

μg/L microgram per liter

mm millimeter
Abstract 1

Occurrence, Distribution, and Loads of

Selected Pesticides in Streams in the

Lake Erie-Lake St. Clair Basin, 1996–98

By Jeffrey W. Frey

Abstract

Thirty pesticides or their degradates were

detected in 315 samples collected from 10

streams in the Lake Erie-Lake St. Clair Basin

between March 1996 and February 1998 as

part of the U.S. Geological Survey’s National

Water-Quality Assessment (NAWQA) Program. Atrazine was detected in every sample,

and deethylatrazine, metolachlor, and simazine

were detected in more than 90 percent of all

samples. Atrazine and metolachlor, the most

heavily applied pesticides in the Basin, had

the highest detected concentrations (85 and

78 micrograms per liter, respectively). No

annual average concentrations exceeded the

U.S. Environmental Protection Agency Maximum Contaminant Level or health advisory

level at any of the surface-water-sampling sites.

Seasonally elevated pesticide concentrations,

however, have economic consequences on

water-treatment facilities required to remove

pesticides in water to meet drinking-water

standards. From May through July, when

most pesticides are transported by runoff into

streams, time-weighted average concentrations of atrazine exceeded the Maximum

Contaminant Level at five row-crop sites,

and time-weighted average concentrations of

atrazine and cyanazine frequently exceeded

lifetime adult health advisories at these same

sites. For some heavily used herbicides such

as atrazine, metolachlor, cyanazine, and acetochlor, elevated concentrations persisted 4 to

6 weeks after the initial maximum concentration in the row-crop streams was measured.

Land use and physical processes can

affect the occurrence and distribution of pesticides. Pesticides were detected at greater

frequency and at higher concentrations in

samples from streams in basins dominated

by row-crop agriculture than in samples from

streams in urban or pasture/forest areas. Maximum measured concentrations were higher

in 1997 than in 1996 and probably were related

to greater precipitation in 1997. Generally,

the number of pesticides detected in a basin

increased with basin size. Pesticide concentrations showed strong seasonal trends related to

the timing and amount of pesticide application.

Row-crop herbicides applied in the spring, such

as atrazine, had maximum measured concentrations in the spring; pesticides typically applied

in late summer and early fall, such as diazinon,

had maximum measured concentrations then.

The increased number of detections and maximum measured concentrations of acetochlor

and the corresponding decrease in the number

of detections and concentrations of alachlor

reflected changes in the amount of pesticides

applied during the sampling period. The percentage of the applied atrazine that was

detected in streams, in general, increased when

the percentage of impermeable soils within

each basin increased.
2 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Loads and yields of selected pesticides

were calculated. The highest loads calculated

were those for atrazine and metolachlor in

the Maumee River at Waterville, Ohio, with

47,000 and 44,000 pounds per year, respectively. Of the row-crop basins, either the

St. Joseph River near Newville, Ind., or the

Auglaize River near Fort Jennings, Ohio, had

the highest yields for the herbicides acetochlor,

alachlor, atrazine, cyanazine, metolachlor, and

simazine. The Cuyahoga River at Cleveland,

Ohio, had the highest yields for diazinon and

prometon—pesticides that typically are applied

heavily in urban areas. The percentage of

the applied atrazine that was calculated in

the stream was determined for each basin

in 1997. The export of atrazine ranged from

0.10 percent at the River Raisin near Manchester, Mich., to 10.6 percent at the St. Joseph

River near Newville, Ind.

Introduction

The Lake Erie-Lake St. Clair Basin is one

of 59 basins and aquifer studies (known as “Study

Units”) in the National Water-Quality Assessment

(NAWQA) Program of the U.S. Geological Survey

(USGS) (Hirsch and others, 1988; Leahy and

others, 1990). These 59 Study Units, which are distributed throughout the Nation, account for 60 to

70 percent of the Nation’s water use and population

served by public water supplies (Leahy and Wilbur,

1991). The overall goals of the NAWQA Program

are to describe the status of and trends in the quality

of ground and surface waters of the United States

and to improve our understanding of natural and

human factors that affect these resources on local,

regional, and national scales.

Study-Unit investigations and national synthesis are the major design features of the NAWQA

Program that allow water-quality information

collected at local and regional scales to be integrated into a national description of water quality.

USGS investigators in the 59 Study Units collect

and analyze water-quality data, following national

protocols for the surface-water, ground-water, and

ecological components of the program design.

These data then are used with other information

from the Study Units to assess water quality at

regional and national scales.

The major components of the Study-Unit

investigations are (1) retrospective analysis of

existing water-quality data, (2) assessment of the

geographic and seasonal distribution of evaluated

contaminants, (3) long-term monitoring to determine water-quality trends, and (4) case studies of

selected contaminants in local areas and specific

hydrologic processes or environmental effects.

Pesticides, nutrients, volatile organic compounds, and suspended sediment are the primary

topics for retrospective analysis and national synthesis in the NAWQA Program. The objectives

of the study described in this report were to describe

the occurrence, distribution, and loads of selected

pesticides and degradates in the streams of the Lake

Erie-Lake St. Clair Basin. Data were collected from

March 1996 to February 1998 at 10 surface-watersampling sites and additionally from March 1996

to February 1999 at 2 of the 10 sites—the St. Joseph

River near Newville, Ind., and the Maumee River at

Waterville, Ohio.

Purpose and Scope

This report describes (1) the occurrence,

distribution, and temporal variation of pesticide

concentrations in selected streams in the Lake

Erie-Lake St. Clair Basin; (2) the relation between

pesticides in surface water in the Basin and land

use, current and historical pesticide use, other

environmental factors, and chemical properties

of the pesticides; (3) the occurrence and temporal

variation of concentrations of degradates of selected pesticides at one stream site in the Basin;

and (4) pesticide loads and yields for selected

streams within the Basin. These analyses are based

upon water samples collected at 10 surface-watersampling sites.
Description of the Lake Erie-Lake St. Clair Basin 3

Acknowledgments

The following USGS employees contributed

to this report: Charles G. Crawford assisted

with the computations and interpretation of the

pesticide loads and reviewed several early drafts;

Jeffrey D. Martin reviewed the quality-assurance

section; Daniel T. Button assisted with map

production and processed the land-use information; Donna N. Myers, Sandra Y. Panshin, and

Dale M. Robertson provided technical reviews;

Martha L. Erwin provided editorial review; and

Patricia H. Long assisted with production of

the text.

Description of the

Lake Erie-Lake St. Clair Basin

Location and Hydrologic Setting

Lake Erie is the smallest (by volume) of

the Great Lakes. About 78.5 percent of the water

supplied to Lake Erie comes from the upper Great

Lakes by way of the St. Clair and Detroit Rivers.

The Lake Erie-Lake St. Clair Basin Study Unit

encompasses approximately 22,300 mi2

 in parts

of five states: Michigan, Indiana, Ohio, Pennsylvania, and New York (fig. 1). Lake Erie also drains

8,900 mi2 in Canada. For the purposes of this study,

the Lake Erie-Lake St. Clair Basin encompasses

that part of the drainage basin to Lake Erie within

the United States and excludes the area drained

by the upper Great Lakes; it is hereafter referred to

as “the Lake Erie Basin” or the “Basin.” Only the

streams on the U.S. side of the Basin were sampled

for this study. A more complete description of the

Study Unit is given by Casey and others (1997).

The Maumee River, the largest river in the

Basin, drains 6,609 mi2 and discharges nearly

24 percent of the streamflow into Lake Erie. Eight

streams—the Clinton, Huron, and Raisin Rivers

in Michigan; the Maumee River in Indiana and

Ohio; the Sandusky, Cuyahoga, and Grand Rivers

in Ohio; and Cattaraugus Creek in New York—

drain approximately 54 percent of the land area

of the Basin.

Physiography

The Lake Erie Basin spans two physiographic

provinces, the Central Lowland Province and the

Appalachian Plateaus Province (Casey and others,

1997). The Central Lowland Province encompasses

nearly 19,000 mi2

 in the western and central areas

of the Basin. The Appalachian Plateaus Province

covers the remaining area in the eastern part of the

Basin. The Central Lowland Province contains two

distinct physiographic sections, the Eastern Lake

Section and the Till Plains Section. The Eastern

Lake Section encompasses 14,300 mi2 of the Basin

in Michigan, northeastern Indiana, and northwestern Ohio; it is dominated by recessional moraines

and beach ridges, lacustrine plains, and outwash

plains. The Till Plains Section encompasses approximately 4,700 mi2 in the southern parts of

the Basin in Indiana and Ohio. The till plains are

characterized by flat topography and thick glacial

deposits.

Geology and Soils

In general, the bedrock in the Lake Erie Basin

varies from west to east; sandstone shale in the

western part changes to shale in the eastern part

of the Basin as it approaches the Appalachian

Plateaus (Casey and others, 1997). Bedrock is predominantly carbonate in the center of the Basin,

which includes the northwestern corner of Ohio,

the northeastern corner of Indiana, and the southeastern corner of Michigan (including the Maumee

River Basin). The bedrock throughout the Basin

is overlain by predominantly unconsolidated Pleistocene deposits that range in thickness from a few

feet to more than 600 ft in parts of the Cuyahoga

Basin.

Two major soil types are found in the Basin—

the Alfisols (74 percent) and Inseptisols (18 percent) (Casey and others, 1997). These relatively

young soils are derived from lacustrine deposits

that have high clay content and are unsorted and
Black

River

Belle

River

Clinton

River

River

H uron

Rouge

Raisin

River

GrandRiver

River

River

Tiffin

Cuyahoga

Black

River

River

St. Joseph

Maumee

River

Blanchard

River

St. Marys

River

River

Sandusky

Auglaize

River

Rive r

MICHIGAN

OHIO

INDIANA

OHIO

OHIO

PENNSYLVANIA

PENNSYLVANIA

NEW YORK

UNITED STATES

CANADA

LAKE ERIE LAKE ST. CLAIR

ERIE

MONROE

FINDLAY

SANDUSKY

ANN

ARBOR

LIMA

TOLEDO

DETROIT

CLEVELAND

AKRON

FORTWAYNE

7

9

3

10

8

2

5

1

6

81

82

85

41

42

43

84

83

80

EXPLAN

Basin boSurface-w

1 River Raisin 2 Clinton River 3 Auglaize Riv4 Cattaraugus C5 Black River n6 Grand River a7 St. Joseph Ri8 Cuyahoga Ri9 Maumee Rive

10 Maumee Rive

Figure 1. Location and surface-water-sampling sites of the Lake Erie-Lake St. Clair Basin.

Ohio

Penn.

N.Y.

Ind.

Mich.

Canada

Detroit River

St. Clair River

Base from U.S. Geological Survey digital data 1:250,000 1983Albers Equal-Area Conic projectionStandard parallels 29 30' and 45 30' central meridian -83 00
Description of the Lake Erie-Lake St. Clair Basin 5

unconsolidated. Subgroups of the two major

types include the Hapludalfs, the Ochraqualfs,

and the Dystrocrepts. The coarse, moderately

well-drained Hapludalfs (an Alfisol) are found in

western Michigan, specifically the River Raisin

Basin. The Ochraqualfs (also an Alfisol) are poorly

drained soils that encompass the area formerly

known as the Black Swamp in the region near

or in the Auglaize River Basin. The Dystrocrepts

(which are Inseptisols) are thin, infertile soils

found in the eastern regions in or near the Cattaraugus Creek Basin. A gradient of poorly drained

Ochraqualf soils, which contain mostly fine clays,

extends from the Auglaize River Basin in the southcentral part of the Lake Erie Basin and surrounding

area to the River Raisin Basin, which contains

moderately well-drained, coarse Hapludalf soils

(fig. 2, p. 6). This gradient has a pronounced effect

on pesticide transport from cropland.

Climate and Hydrologic Conditions

Precipitation in the Lake Erie Basin during

the study period was about 120 percent of the mean

monthly or “normal” (based on the 1961–90 average computed from data for the precipitation

stations listed in table 1). Precipitation generally

was above normal in the eastern and the western

parts of the Basin during 1996 and 1997 (fig. 3,

p. 7). This precipitation resulted in above-normal

streamflows during much of the study period,

especially in the western part of the Basin. Streamflows were above normal in 16 of the 24 months

during which samples were collected (fig. 3).

Heavy rains in spring 1996 in the western part of

the Basin resulted in record or near-record streamflows and unusually high runoff, especially in the

northwestern part of the Basin but also throughout

Michigan, Indiana, and Ohio. The highest streamflow of record (1947–98) occurred in the St. Joseph

River near Newville, Ind., during May 1996.

Table 1. National Weather Service precipitation stations

used to compute 30-year (1961–90) normalsa for four

surface-water-sampling sites in the Lake Erie-Lake

St. Clair Basin

a

The 30-year normals for precipitation were calculated, when

possible, by averaging the monthly precipitation data from 1961

through 1990 from two rain gages near the surface-water-sampling

sites.

b

Sites taken from Midwest Regional Climate Center, 1999.

Land and Water Use

Agriculture is the predominant land use in

the Lake Erie Basin (fig. 4, p. 8); it accounts for

65 percent of the total area of the Basin (table 2,

p. 9). Of the agricultural lands, row crops (mostly

corn and soybeans) account for 48 percent and pasture for 17 percent. In 1995, 6 million acres in the

Basin were planted with crops (Brody and others,

1998). Soybeans and corn accounted for more than

73 percent of total planted acres (41 and 32.5 percent, respectively). Other significant crops include

wheat, hay, and oats.

The second most common land use is urban.

Although urban land accounts for only 10 percent

of the Basin, there are several large urban areas—

including Detroit, Mich.; Fort Wayne, Ind.; Cleveland, Toledo, and Akron, Ohio; and Buffalo, New

York. In 1990, the population in the Basin was

Station nameb Station number

Black River near Jeddo, Mich.

Lapeer, Mich. 204655

Port_Huron_Sewage_Plant 206680

St. Joseph River near Newville, Ind.

Fort_Wayne_WSO_AP 123037

Defiance, Ohio 332098

Auglaize River near Fort Jennings, Ohio

Lima_WWTP 334551

Van_Wert 338609

Cattaraugus Creek at Gowanda, N.Y.

Fredonia, N.Y. 303033
Black

River

Belle

River

Clinton

River

River

H uron

Rouge

Raisin

River

Grand

River

River

River Tiffin

Cuyahoga

Black

River

River

St. Joseph

Maumee

River

Blanchard

River

St. Marys

River

River

Sandusky

Auglaize

River

River

7

9

10

2

5

1

6

MICHIGAN

OHIO

INDIANA

OHIO

OHIO

PENNSYLVANIA

PENNSYLVANIA

NEW YORK

UNITED STATES

CANADA

81

82

41

42

85

43

84

83

80

HMSlVeSu

1 Riv2 Clin3 Aug4 Catt5 Bla6 Gra7 St. J8 Cuy9 Mau

10 Mau

Figure 2. Infiltration rates of soils in the Lake Erie-Lake St. Clair Basin.

8

Detroit River

St. Clair River

3

Base from U.S. Geological Survey digital data 1:2,000,000 1983Albers Equal-Area Conic projectionStandard parallels 29 30' and 45 30' central meridian -83 00
96

MARCH

96

APRIL

96

MAY

96

JUNE

96

JULY

96

AUGUST

96

SEPTEMBER

96

OCTOBER

96

NOVEMBER

96

DECEMBER

97

JANUARY

97

FEBRUARY

97

MARCH

97

APRIL

97

MAY

97

JUNE

97

JULY

97

AUGUST

97

SEPTEMBER

97

OCTOBER

97

NOVEMBER

97

DECEMBER

98

JANUARY

98

FEBRUARY

V1

0

300

100200

PERCENTAGE OF

MEAN MONTHLY

PRECIPITATION

96

MARCH

96

APRIL

96

MAY

96

JUNE

96

JULY

96

AUGUST

96

SEPTEMBER

96

OCTOBER

96

NOVEMBER

96

DECEMBER

97

JANUARY

97

FEBRUARY

97

MARCH

97

APRIL

97

MAY

97

JUNE

97

JULY

97

AUGUST

97

SEPTEMBER

97

OCTOBER

97

NOVEMBER

97

DECEMBER

98

JANUARY

98

FEBRUARY

V1

0

1,200

200400600800

1,000

PERCENTAGE OF

MEAN MONTHLY

STREAMFLOW

0

10,000

2,0004,0006,0008,000

STREAMFLOW, IN

CUBIC FEET PER

SECOND

96

MARCH

96

APRIL

96

MAY

96

JUNE

96

JULY

96

AUGUST

96

SEPTEMBER

96

OCTOBER

96

NOVEMBER

96

DECEMBER

97

JANUARY

97

FEBRUARY

97

MARCH

97

APR

V1

0

300100200

96

MARCH

96

APRIL

96

MAY

96

JUNE

96

JULY

96

AUGUST

96

SEPTEMBER

96

OCTOBER

96

NOVEMBER

96

DECEMBER

97

JANUARY

97

FEBRUARY

97

MARCH

97

APRI

M

V1

0

600

100200300400500

0

12,000

2,0004,0006,0008,000

10,000

96

MARCH

96

APRIL

96

MAY

96

JUNE

96

JULY

96

AUGUST

96

SEPTEMBER

96

OCTOBER

96

NOVEMBER

96

DECEMBER

97

JANUARY

97

FEBRUARY

97

MARCH

97

APRIL

97

MAY

97

JUNE

97

JULY

97

AUGUST

97

SEPTEMBER

97

OCTOBER

97

NOVEMBER

97

DECEMBER

98

JANUARY

98

FEBRUARY

V1

0

300

100200

PERCENTAGE OF

MEAN MONTHLY

PRECIPITATION

96

MARCH

96

APRIL

96

MAY

96

JUNE

96

JULY

96

AUGUST

96

SEPTEMBER

96

OCTOBER

96

NOVEMBER

96

DECEMBER

97

JANUARY

97

FEBRUARY

97

MARCH

97

APRIL

97

MAY

97

JUNE

97

JULY

97

AUGUST

97

SEPTEMBER

97

OCTOBER

97

NOVEMBER

97

DECEMBER

98

JANUARY

98

FEBRUARY

V1

0

400

100200300

PERCENTAGE OF

MEAN MONTHLY

STREAMFLOW

M

A

M J J A S O

N

D J F M

A

M J J A S O

N

D J F

1996 1997 1998

0

8,000

2,0004,0006,000

STREAMFLOW, IN

CUBIC FEET PER

SECOND

A

BLACK RIVER NEAR JEDDO, MICH.

B

ST. JOSEPH RIVE

C

AUGLAIZE RIVER NEAR FORT JENNINGS, OHIO

96

MARCH

96

APRIL

96

MAY

96

JUNE

96

JULY

96

AUGUST

96

SEPTEMBER

96

OCTOBER

96

NOVEMBER

96

DECEMBER

97

JANUARY

97

FEBRUARY

97

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97

APRI

M

V1

0

300

100200

96

MARCH

96

APRIL

96

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96

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96

JULY

96

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96

SEPTEMBER

96

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96

NOVEMBER

96

DECEMBER

97

JANUARY

97

FEBRUARY

97

MARCH

97

APRI

M

MONTH

0

400

100200300

CATTARAUGUS C

D

M

A

M J J A S O

N

D J F M

A

1996 

0

12,000

2,0004,0006,0008,000

10,000

Mean monthly ave

Figure 3. Percentage of mean monthly precipitation, percentage of mean monthly streamflow, and streamflow from March 1996 tsurface-water-sampling sites in the western part of the Lake Erie Basin-Lake St. Clair Basin

—(A) Black River near Jeddo, Mich., 

Newville, Ind., (C) Auglaize River near Fort Jennings, Ohio

—and one site in the eastern part of the Basin, (D) Cattaraugus Creek 

,
PENNSYLVANIA

OHIO

MICHIGAN

OHIO

INDIANA

OHIO

PENNSYLVANIA

NEW YORK

UNITED STATES CANADA

7

9

3

10 8

2

5

1

6 Row 

PastuUrbanForesWetlaOpen OtherSurfa

 1 River R 2 Clinton  3 Auglaiz 4 Cattarau 5 Black R 6 Grand R 7 St. Jose 8 Cuyaho 9 Maume10 Maume

. .

41

42

43

80

81

82

83

84

85

Base from U.S. Geological Survey digital data 1:2,000,000 1983Albers Equal-Area Conic projectionStandard parallels 29 30' and 45 30' central meridian -83 00
Description of the Lake Erie-Lake St. Clair Basin 9

Table 2. Drainage area, land use, percent permeable soils, and base-flow index for surface-water-sampling sites in the Lake Er

[Values taken from the Multi-Resolution Land Characteristics coverage (Vogelmann, Sohl, and others, 1998; Vogelmann, Sohl, and Howard, 1998) based upo(Anderson and others, 1976) (minor uses are not included in the table); mi2, square miles; nd, no data; na, not applicable]

Percent land use in Basin

Agriculture Foresta Urbanb

aIncludes Anderson classes: mixed forest, deciduous forest, evergreen forest, woody wetlands.

bIncludes Anderson classes: low-intensity residential, high-intensity residential, commercial/industrial/transportation, quarries/strip mines/gravel pits, a

Site number and name

Drainage area

(mi2)

 Primary

land use

Row

crop Pasture

cBased on the Natural Resources Conservation’s State Soil Geographic Data Base (STATSGO) values for hydrologic soils groups A and B, the most pedBased on the ratio of ground-water discharge to surface-water discharge (Rutledge, 1998).

1. River Raisin near Manchester, Mich. 132 Row crop 44 13 36 2 2. Clinton River at Sterling Heights, Mich. 309 Urban 19 8 40 25 3. Auglaize River near Fort Jennings, Ohio 332 Row crop 76 13 8 2 4. Cattaraugus Creek at Gowanda, N.Y. 436 Pasture 6 35 58 1 5. Black River near Jeddo, Mich. 464 Row crop 72 12 14 1 6. Grand River at Harpersfield, Ohio 552 Pasture 20 22 54 1 

7. St. Joseph River near Newville, Ind. 610 Row crop 54 24 20 1 8. Cuyahoga River at Cleveland, Ohio 788 Urban 8 19 44 25 9. Maumee River at New Haven, Ind. 1,967 Row crop 66 16 12 4 

10. Maumee River at Waterville, Ohio 6,330 Row crop 74 13 9 3 

Lake Erie-Lake St. Clair Basin 22,300 Row crop 48 17 9 10 
10 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

10.4 million; the Detroit, Cleveland, and Buffalo

Metropolitan Areas accounted for 62 percent of

the total population.

About 98 percent of the total amount of water

use in the Lake Erie Basin comes from surface

water (Casey and others, 1997). Power generation

accounts for about 77 percent of the total water

use, followed by industrial, domestic, public, and

agricultural uses. Most drinking-water supplies,

which are included in the public- and domesticuse groups, are provided by surface-water sources

(91.8 and 85.2 percent, respectively); the remainder

comes from ground water.

Pesticide Use

Pesticides are used widely in the extensive

row-crop agricultural areas in the Basin. No

pesticide-use data, however, are collected by states

for 16 of the 44 pesticides evaluated in this report.

Also, some of the most heavily used pesticides in

the Basin, such as glyphosate, were not evaluated

in this study. Regardless of the missing data, herbicides are applied more heavily than insecticides

(fig. 5); approximately 8.1 million pounds of herbicides and more than 28,100 pounds of insecticides

were applied to agricultural areas in the Basin

in 1995 (Brody and others, 1998). Herbicides are

applied during spring planting to nearly all corn

and soybean fields. Metolachlor (an acetanilide

herbicide used on soybeans and corn) and atrazine

(a triazine herbicide used primarily on corn) were

the most heavily used pesticides in the Basin during

1995 (Brody and others, 1998; table 3, p. 12). More

than 2.0 and 1.7 million pounds of metolachlor

and atrazine, respectively, were applied. More

than 100,000 pounds of active ingredient of cyanazine, acetochlor, alachlor, glyphosate, 2,4-D,

pendimethalin, dicamba, metribuzin, and dimethenamid also were applied. Insecticides occasionally

are applied to corn in the summer but usually are

not applied to soybeans. Chlorpyrifos, carbaryl, and

ethoprop were the most heavily used insecticides

in the Basin.

Use of pesticides in urban and other nonagricultural areas in the Lake Erie Basin is not as well

documented as that in agricultural areas. Insecticides usually represent a larger percentage of the

total amount of pesticides used in urban areas than

in row-crop agricultural areas. The herbicide 2,4-D

is the most heavily applied pesticide in urban and

other nonagricultural areas of the U.S.; an estimated 17 to 22 million pounds of active ingredient

were used in 1994 (Aspelin, 1997). The insecticides chlorpyrifos, diazinon, and malathion, and

the herbicides glyphosate, dicamba, and MCPP

also commonly are used in urban areas.

The total amount of pesticides applied cannot

be determined accurately with existing data because most states require that statistics be kept for

only the most heavily used pesticides. For example,

according to Brody and others (1998), no data have

been systematically collected on the application

of simazine in the Lake Erie Basin. Simazine was

detected in 93.4 percent of the samples collected

in this study. Data also are not reported or rarely are

reported for pesticides used in urban and other areas

(such as highway medians). For example, prometon

(a nonselective triazine herbicide) commonly is

applied for “total vegetation control on industrial

sites and under asphalt roads” (Capel and others,

1999). Prometon was detected in 75.7 percent of

the samples, which indicates this pesticide was

used in the study area. The quantity and quality of

pesticide-use data collected by states vary, making

Basin-wide estimates difficult. For example, Brody

and others (1998) note that pesticide usage in the

Lake Erie Basin probably is underestimated because New York State does not keep statistics on

pesticide use. Data from Brody and others (1998)

are used in this report, however, because they

provide the best available estimate of agricultural

pesticide use in the Lake Erie Basin during this

study.

Sampling-Site Locations

Water quality in streams is affected by a complex combination of natural and human factors.

To contrast these influences, NAWQA Study Units

are stratified into smaller areas that have relatively
Description of the Lake Erie-Lake St. Clair Basin 11

Metolachlor

Atrazine

Cyanazine

Acetochlor

Alachlor

Glyphosate

Pendimethalin

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

AMOUNT OF PESTICIDE APPLIED, IN POUNDS

OF ACTIVE INGREDIENT PER YEAR

Chlorpyrifos

Carbaryl

Ethoprop

Endosulfan

Phorate

Azinphos-methyl

Methamidophos

Cryolite

Imidacloprid

Methyl Parathion

0

8,000

2,000

4,000

6,000

HERBICIDES

INSECTICIDES

 Figure 5. Amount of agricultural-use herbicides and insecticides applied in 1995 in the

Lake Erie-Lake St. Clair Basin (from Brody and others, 1998).

Pesticides in bold are evaluated in this study

homogenous combinations of land use and physical

characteristics (Gilliom and others, 1995). For

this study, 10 surface-water-sampling sites were

selected that represent typical streams in the

Basin and contrast the major surficial and bedrock

geology and land-use types (table 2). Surfacewater-sampling sites were selected for purposes

of comparison as being either (1) small and relatively homogenous or (2) large and heterogenous to

represent the integrated effects of many upstream

factors. The smaller sampling sites were as large

as possible yet still representative of a single, major

land use. The three land-use classes that differentiate the basins are row-crop agriculture, urban, and

pasture/forest. Because there are no streams of sufficient size (50 percent or more of the land area

in the basin) that flow entirely through urban or

pasture/forest areas in the Basin, sampling sites

were selected in streams that drain significant

amounts of land in urban or pasture/forest use.

Sampling sites also were selected to represent

a gradient from poorly drained to well-drained

soils. Soil types were differentiated, based on the

National Resources Conservation Service’s State

Soil Geographic Data Base (STATSGO) (Wolock,

1997).

The River Raisin, the smallest stream in the

study, drains 132 mi2 near Manchester, Mich.

This basin lies within the Eastern Lake section of
12 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Table 3. Characteristics of compounds analyzed and their use in the Lake Erie-Lake St. Clair Basin study area in 1995

[Method: Pesticide degradates in bold were sampled only at the St. Joseph River near Newville, Ind.; MDL, method detection limit; a.i., active

ingredient; μg/L, microgram per liter; ESA, ethane sulfonic acid; OA, oxanilic acid; GC/MS, gas chromatography/mass spectrometry; HPLC,

high-performance liquid chromatography; nd, no data; na, not applicable (degradate). Family: AM, amide; TR, triazine; OP, organophosphate;

DI, dinitroanaline; CA, carbamate; OC, organochlorine; UR, urea; PY, pyrethroid; MI, miscellaneous; UL, uracil. Type: H, herbicide; I, insecticide; d-H, herbicide degradate product; d-I, insecticide degradate product]

Compound

Trade

or

common

name(s)a Family Type

Method

of

analysis

MDL

(μg/L)

Runoff

potentialb

Estimated

agricultural usec

in 1995

(in

1,000 pounds

of a.i.)

Acetochlor Harness, Surpass AM H GC/MS 0.002 medium 703.5

Acetochlor ESA None AM d-H HPLC .20 nd na

Acetochlor OA None AM d-H HPLC .20 nd na

Alachlor Lasso AM H GC/MS .002 medium 577.0

Alachlor ESA None AM d-H HPLC .20 nd na

Alachlor OA None AM d-H HPLC .20 nd na

Atrazine AAtrex TR H GC/MS .001 large 1,729.5

Atrazine, deethyl None TR d-H GC/MS .002 nd na

Atrazine, deisopropyl None TR d-H GC/MS .05 nd na

Atrazine, hydroxy None TR d-H HPLC .20 nd na

Azinphos, methyl Azinos, Gusathion A OP I GC/MS .001 medium nd

Benfluralin Ballin, Benefin DI H GC/MS .002 medium nd

Butylate Sutan +, Genate Plus CA H GC/MS .002 large nd

Carbaryl Sevin, Savit, Slam CA I GC/MS .003 medium 3.2

Carbofuran Furadan, Terrafuran CA I GC/MS .003 large .1

Chlorpyrifos Lorsban, Scout OP I GC/MS .004 small 7.6

Cyanazine Bladex TR H GC/MS .004 medium 893.1

Cyanazine amide None TR d-H GC/MS .05 nd na

DCPA Dacthal OC H GC/MS .002 medium .07

DDE, p,p’ None OC d-I GC/MS .006 medium 0

Diazinon Spectracide, Sarolex OP I GC/MS .002 large .1

Dieldrin Panoram-D-31 OC I GC/MS .001 medium nd

Diethylanaline-2,6 None AM d-H GC/MS .003 nd na

Disulfoton Di-Syston OP I GC/MS .017 large .01

EPTC Eptam, Eradicane CA H GC/MS .002 medium .11

Ethalfluralin Sonalan, Curbit DI H GC/MS .004 medium .2

Ethoprop Mocap OP I GC/MS .003 medium 2.1

Fonofos Dyfonate, Cudgel OP I GC/MS .003 large .6
Table 3. Characteristics of compounds analyzed and their use in the Lake Erie-Lake St. Clair Basin study area in

1995—Continued

Description of the Lake Erie-Lake St. Clair Basin 13

HCH, alpha None OC I GC/MS 0.002 nd nd

HCH, gamma Lindane OC I GC/MS .004 large na

Linuron Lorax, Linex UR H GC/MS .002 large 91.0

Malathion Cythion, Acimal OP I GC/MS .005 small .4

Metolachlor Dual, Pennant AM H GC/MS .002 large 2,018.8

Metolachlor ESA None AM d-H HPLC .20 nd na

Metolachlor OA None AM d-H HPLC .20 nd na

Metribuzin Lexone, Sencor TR H GC/MS .004 large 143.1

Molinate Ordram CA H GC/MS .004 medium nd

Napropamide Devrinol AM H GC/MS .003 large 1.2

Parathion Orthophos, Panthion OP I GC/MS .004 medium nd

Parathion, methyl Penncap-M, Prompt OP I GC/MS .006 medium 1.0

Pebulate Tillam CA H GC/MS .004 medium 1.5

Pendimethalin Prowl, Stomp DI H GC/MS .004 medium 359.3

Permethrin, cis Ambush, Pounce PY I GC/MS .005 small .4

Phorate Thimet, Rampart OP I GC/MS .002 large 1.6

Prometon Pramitol TR H GC/MS .003 large nd

Pronamide Kerb AM H GC/MS .003 large nd

Propachlor Ramrod AM H GC/MS .007 medium nd

Propanil Stampede AM H GC/MS .004 medium nd

Propargite Comite, Omite MI I GC/MS .013 medium nd

Simazine Aquazine, Princep TR H GC/MS .005 large nd

Tebuthiuron Spike UR H GC/MS .010 large nd

Terbacil Sinbar UL H GC/MS .007 large .02

Terbufos Counter OP I GC/MS .013 medium .3

Thiobencarb Bolero, Saturn CA H GC/MS .002 medium nd

Triallate Far-Go CA H GC/MS .001 large nd

Trifluralin Treflan, Trilin DI H GC/MS .002 medium 11.3

a

From Sine (1995).

b

From Goss (1992).

c

From Brody and others (1998).

Compound

Trade

or

common

name(s)a Family Type

Method

of

analysis

MDL

(μg/L)

Runoff

potentialb

Estimated

agricultural usec

in 1995

(in

1,000 pounds

of a.i.)
14 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

the Central Lowland Province. The bedrock—

a combination of shales, siltstone, and imbedded

sandstone—is overlain by moderately well-drained

soils. In the gradient of poorly drained to welldrained soils for the agricultural basins, the River

Raisin has the most well-drained soils. Nearly

90 percent of the streamflow is derived from ground

water (table 2). Row-crop agriculture is the predominant land use (44 percent), but a significant

amount (36 percent) is forested.

The Clinton River drains 309 mi2 at Sterling

Heights, Mich. This basin lies within the Eastern

Lake Section of the Central Lowland Province. The

sandstone-shale bedrock is overlain by moderately

well-drained till and coarse soils. Approximately

78 percent of the streamflow is derived from ground

water. The Clinton River Basin was selected to

represent urban land use, which accounts for

25 percent of the land in this basin. Forty percent

of this basin is forested; 19 percent is planted in

row crops, mostly in the headwaters region.

The Auglaize River drains 332 mi2 near Fort

Jennings, Ohio. This basin lies within the Till

Plains Section of the Central Lowland Province.

The bedrock is predominantly carbonate. The

Auglaize River Basin, which drains the former

Black Swamp, contains very poorly drained soils

that have a large clay content and that require

tile drains and ditches to make them suitable for

farming. In the gradient of poorly drained to welldrained soils, this basin has the most poorly drained

soils. Approximately 30 percent of streamflow

comes from ground water. The primary land use

in this basin is row-crop agriculture. It is the most

heavily farmed basin of the basins studied, with

76 percent in row crops. The Auglaize River

is the source of drinking water for several small

communities.

Cattaraugus Creek drains 436 mi2 at Gowanda,

N.Y., and is the easternmost site in the Basin.

It flows through the Appalachian Plateaus Province.

The shale bedrock is overlain by moderately

well-drained to poorly drained soils. Approximately 57 percent of the streamflow comes from

ground water. This basin was selected to represent

pasture/forest land use because of the large amount

(35 percent) used for pasture. This basin also has

the most forested areas (58 percent) of all the basins

in the study area. The hilly terrain of the Appalachian Plateaus Province makes farming difficult;

thus, this basin has the smallest amount of row-crop

agriculture acreage (6 percent) in the study area.

The Black River near Jeddo, Mich., drains

464 mi2 and is the northernmost basin in the study.

This basin lies within the Eastern Lake Section

of the Central Lowland Province. The sandstone

and shale bedrock is overlain by poorly drained

till and fine soils. Approximately 37 percent of the

streamflow is derived from ground water. Row-crop

agriculture is the primary land use and accounts

for 72 percent of the land.

The Grand River drains 552 mi2 at Harpersfield, Ohio, and flows through the Appalachian

Plateaus Province. The shale and sand/shale bedrock underlies mostly till soils that are moderately

drained to very poorly drained. Ground water contributes about 33 percent of the streamflow. This

basin was selected to represent pasture/forest

land use; about 22 percent is used as pasture, and

54 percent is forested. The Grand River supports

the most diverse biological communities of the

10 surface-water-sampling sites in this study area

(Stephen Rheaume, U.S. Geological Survey, oral

commun., 1999).

The St. Joseph River drains 610 mi2 near

Newville, Ind. Parts of this basin are within either

the Till Plains or Eastern Lake Sections of the

Central Lowland Province. The poorly drained soils

are mostly till that have high clay content and overlay sandstone and shale bedrock; these soils require

tile drains for farm use. About 62 percent of the

streamflow comes from ground water. Row-crop

agriculture, primarily corn and soybeans, is the

primary land use (54 percent). The St. Joseph River

is the source of drinking water for the city of Fort

Wayne, Ind.

The Cuyahoga River drains 788 mi2

 at Cleveland, Ohio, and flows through the Appalachian

Plateaus Province. The sandstone-shale bedrock is

overlain by till and coarse soils that are moderately

well-drained to poorly drained. Ground water contributes about 66 percent of the streamflow. This

basin was selected to represent urban land use;
Analytical and Sampling Methods 15

about 25 percent of the basin is urban land, mostly

the Cleveland Metropolitan Area. About 44 percent

of this basin is forested, mainly in the headwaters,

and 8 percent of the basin is planted in row crops.

The Maumee River at New Haven, Ind., drains

1,967 mi2 near Fort Wayne, Ind. Parts of this basin

are within either the Till Plains or Eastern Lake

Sections of the Central Lowland Province. The

poorly drained till soils overlay a sandstone-shale/

carbonate bedrock and require tile drains for farm

use. Ground water accounts for 51 percent of the

streamflow. This basin was selected to represent

multiple land uses, but about 66 percent is used for

row-crop agriculture. The St. Joseph River Basin

lies within the Maumee River Basin.

The Maumee River at Waterville, Ohio, drains

6,330 mi2 and is the largest stream in the Lake Erie

Basin. It flows through the Till Plains and Eastern

Lake Sections of the Central Lowland Province.

This basin has moderately well-drained to poorly

drained soils over predominantly carbonate and

sandstone/shale bedrock. Approximately 33 percent of the streamflow is derived from ground

water. This basin was selected to represent the

effects of multiple land uses, but row-crop agriculture is the primary land use, with 74 percent of the

basin in row crops. The St. Joseph River, Auglaize

River, and Maumee River at New Haven lie within this basin. The Maumee River is the source of

drinking water for the cities of Defiance, Napoleon,

Grand Rapids, and Maumee, Ohio.

Analytical and Sampling Methods

The NAWQA Program evaluates pesticides for

analysis that (1) are among the most heavily used

pesticides in the U.S., (2) have potentially adverse

human-health or environmental effects, and (3) are

amenable to analysis by gas chromatography/mass

spectroscopy (GC/MS). Forty-four pesticides and

three degradates are compared among all surfacewater-sampling sites in this report. Of these, 26 are

herbicides, 18 insecticides, 2 herbicide degradates,

and 1 insecticide degradate (table 3). These pesticides (except for acetochlor) accounted for about

72 and 66 percent, respectively, of the estimated

annual application of herbicides and insecticides

in the United States between 1990 and 1993 (Larson and others, 1999).

Additionally, 10 samples from the St. Joseph

River near Newville, Ind., were analyzed for nine

selected degradates of the heavily used herbicides

atrazine, metolachlor, alachlor, acetochlor, and

cyanazine (table 3). All the degradates in these

10 samples were analyzed, using high-performance

liquid chromatography (HPLC); exceptions were

deisopropylatrazine and cyanazine amide, which

were analyzed using GC/MS. In total, 56 pesticides

or degradates will be discussed in this report.

Field Methods

Water samples were collected at equal-width

increments across the stream in 1- or 3-liter Teflon

bottles placed into a USGS D-77 sampler. The D-77

sampler is designed to collect equal amounts of

streamwater at all depths (depth-integrated). Samples were composited by pouring the water through

a Teflon conesplitter into stainless-steel or Teflon

containers. Approximately 900 mL of sample were

filtered to remove sediment and organic debris

by passing the water through a 0.7-mm glass-fiber

filter into a 1-L baked-glass bottle. Pesticides were

extracted by pumping these samples through C-18

solid-phase extraction (SPE) cartridges. Detailed

descriptions of equipment and procedures used

to decontaminate the sampling equipment and to

collect, process, and extract the samples, using the

SPE method, are in Shelton (1994). Samples were

packed on ice and shipped to the USGS National

Water Quality Laboratory (NWQL) in Arvada,

Colo., for analysis. For the 10 additional samples

collected for degradate analyses from the St. Joseph

River near Newville, Ind., another aliquot was

taken and filtered through a 0.7-mm glass-fiber

filter. Two 125-mL standard brown glass bottles

were filled with the filtered water, packed on ice,

and shipped to the Organic Geochemistry Research

Laboratory in Lawrence, Kans., for analysis.

The transport of pesticides into streams or

surface-water bodies is affected by the timing of

pesticide application and subsequent runoff. Conse-
16 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

quently, samples were collected more frequently

during the growing season after many pesticides

have been applied. Samples were collected at

six surface-water-sampling sites at least monthly

between March and April 1996 until February 1998

and twice monthly during the growing season

(May–August) in 1997. Samples were collected

at another four surface-water sites at least monthly

throughout the same time frame and more frequently during the growing season; samples were

collected at least monthly in 1996, three to four

times per month during the growing season in 1997,

and twice monthly in 1998. When possible, samples also were collected to coincide with rising,

peak, and falling stages of the streamflow hydrograph at a higher frequency and still adhere to the

weekly, bimonthly, or monthly sampling schedule.

Approximately 52 percent of the samples were

collected on the rising (12.8 percent), peak (7.5 percent), and falling (31.5 percent) stages of the

streamflow hydrograph (fig. 6).

Overall, 315 samples were collected and

analyzed for pesticides at the 10 surface-watersampling sites in the Lake Erie Basin between

March 1996 and February 1998. At the six

less-intensively sampled sites (River Raisin,

Cattaraugus Creek, Black River, Grand River,

Cuyahoga River, and the Maumee River at New

Haven), from 24 to 29 samples were collected. At

the more-intensively sampled sites (Clinton River,

Auglaize River, St. Joseph River, and the Maumee

River at Waterville), from 33 to 36 samples were

collected. Additionally, 10 samples were collected

at the St. Joseph River near Newville, Ind., between

May 1997 and March 1998 as part of a national

USGS study at selected NAWQA surface-watersampling sites to evaluate the occurrence of some

degradates of heavily used herbicides acetochlor,

alachlor, atrazine, cyanazine, and metolachlor.

Laboratory Methods

The SPE cartridges were eluted at the NWQL

and then analyzed by GC/MS for separation and

analysis of the pesticides (Zaugg and others, 1995).

Pesticides were identified and quantified, using

a mass selective detector operating in the selective ion monitoring mode. Each compound has a

method detection limit (MDL), which is the minimum concentration at which a substance can be

identified with 99 percent confidence that the concentration is greater than zero (Martin and others,

1999). Concentrations near the method detection

low

Stable Rising Peak Falling

normal

Stable

high

Stable

HYDROLOGIC CONDITION

0

40

10

20

30

PERCENTAGE OF SAMPLES

305 total samples

(STAGE OF STREAMFLOW HYDROGRAPH)

Figure 6. Percentage of samples collected for each hydrologic condition at 10 surface-watersampling sites, Lake Erie-Lake St. Clair Basin, 1996–98.
Analytical and Sampling Methods 17

limit were not censored; instead, compounds detected below the MDL were remarked as “E”

(estimated) in the analytical results reported by

the NWQL.

Parent compounds and several degradates of

triazine herbicides were separated from the water

samples, using C-18 SPE; they were analyzed,

using GC/MS. Degradates for all acetanilide herbicides and one atrazine compound were isolated

from the samples, using C-18 SPE; they were identified and quantified, using HPLC coupled with

mass spectroscopy (MS) by means of electrospray ionization and negative ion detection. Liquid

chromatography/mass spectrometry (LC/MS) is

necessary for analysis because, using the GC/MS

method, the ionic characteristics of the degradates

make recovery difficult. Evaluated pesticides and

degradates were extracted in the laboratory by

passing 100 mL of sample through a C-18 SPE

cartridge. For further details on methods, see Ferrer

and others (1997) and Zimmerman and Thurman

(1999).

Quality-Assurance Procedures

Field blanks, field spikes, and split replicates

were used to estimate sample contamination and

matrix effects and to determine variability affecting

the pesticide concentrations, following the qualitycontrol design of the NAWQA Program (Mueller

and others, 1997). Blanks and spikes were used

to estimate bias. Replicates were used to determine

variability. The precision and bias associated with

the pesticide samples were estimated, using 7 field

blanks, 15 field spikes, and 10 split replicates.

Of the seven pesticides detected in the blanks,

only metolachlor was detected in more than two

samples—but it was detected at such low concentrations (median of 0.003 μg/L and maximum of

0.007 μg/L) that the interpretation of the data

was not affected. In the 15 field spikes, 26 of the

pesticides were within 10 percent of 100-percent

recovery. For 40 of the 47 pesticides analyzed

in the spikes by the GC/MS method, the mean percent recovery ranged from 71 to 130 percent. Of

the seven pesticides outside this range, deethylatrazine, disulfuton, phorate, and p,p’-DDE were

biased low; carbaryl, carbofuran, and tebuthiuron

were biased high. Further discussion of qualityassurance procedures followed in this study is

provided in appendix A.

Computation of Pesticide Loads

The load of a chemical in a stream is defined

as the mass of the chemical passing by a fixed measuring point in a specified period of time. Average

annual loads of pesticides for this study were estimated, using the rating-curve method (Cohn and

others, 1989, 1992; Crawford, 1991, 1996). This

method allows an estimate of daily loads to be made

from relatively few samples when daily streamflow

data are available. Loads can be calculated by multiplying the concentration of the chemical in the

sample by the streamflow in the stream at the time

of sample collection and an appropriate unit’s conversion factor.

Concentrations of pesticides detected in this

study showed a strong seasonal pattern related to

the timing of application of the pesticides and their

subsequent runoff from the land surface. Consequently, a rating curve incorporating two seasonal

periods was used

ln L = b0 + b1 period + b2 ln Q + b3 ln (Q * period),

where,

ln indicates the natural logarithm

of the quantity,

L is pesticide load,

b0, b1,

b2, and

b3 are rating-curve parameters,

Q is daily value streamflow, and

period is a variable equal to 1 if

an observation falls within a

selected month and 0 otherwise.

For pesticides commonly applied during

spring, such as the agricultural herbicides atrazine and metolachlor, the seasonal periods used

were May through July and August through April.

For pesticides commonly applied in mid to late

summer, such as chlorpyrifos or diazinon, the

seasonal periods used were July through September
18 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

May-July data

August-April data

LOGARITHM OF ATRAZINE LOAD,

IN POUNDS PER DAY

LOGARITHM OF STREAMFLOW, 

IN CUBIC FEET PER SECOND

-3

-2

-1

0

1

2

3

4

5

6

7

3456789

Figure 7. Seasonal relation of atrazine load to streamflow,

St. Joseph River near Newville, Ind., 1996-98.

and October through June. An example of the

seasonal relation between load of a pesticide

(atrazine) and streamflow is shown in figure 7.

Because some of the concentrations reported were below the detection limit, rating-curve

parameters were estimated by the linear attribution

method (Chatterjee and McLeash, 1986) rather

than the linear least squares method. A correction

for transformation bias was made, using Duan’s

(1983) method when converting model predictions

in logarithmic units to arithmetic units (Miller,

1984). This was done because model parameters

were estimated, using a model in which the

response variable (load) is log transformed.

Given a time series of streamflow data, such

as that available from a USGS streamflow-gaging

station, the average pesticide load, , can be estimated by:

where,

is the estimated load obtained from

the rating curve for the ith value of

streamflow in the time series, and

N is the total number of streamflow

values.

The accuracy of this estimate is a function

of the accuracy with which the rating curve describes the relation between pesticide load and

streamflow and the interval between streamflow

observations in the time series. For small streams

in which flow is highly responsive to runoff, a short

interval between streamflow values in the time

series may be required. For larger, less responsive

streams, a daily or longer interval may be sufficient.

A time series of daily mean streamflow values

L

L

i=1

Σ

N Lˆ i

N = ----- ,

Lˆi
Occurrence, Distribution, and Loads of Selected Pesticides 19

usually is used to compute average loads because

these values readily are available. Because some of

the streams sampled for this study are small, however, the use of daily mean flows and hourly flows

for computing average loads was compared at a

subset of the surface-water-sampling sites for a few

pesticides. The average annual loads were similar

between the two sets of estimates, computed as the

percent difference defined as:

[y - x/(y+x)/2] * 100,

where,

y is load obtained, using the daily

mean streamflow, and

x is load obtained, using the hourly

streamflow.

Most of the load estimates had relative differences of 0 to 4 percent; loads of acetochlor had the

greatest relative difference of less than 7 percent.

Consequently, daily mean streamflows were used

to compute all average loads in this report.

The degree of uncertainty in the loads was estimated, using the jackknife method (Efron, 1982).

(Crawford, 1996, presents a more-detailed description of the methods used to compute pesticide loads

in this report.) Yields were calculated by dividing

loads by the drainage area of each basin.

Occurrence, Distribution, and Loads

of Selected Pesticides

Pesticide Detections and Concentrations

Of the 44 pesticides and three degradates evaluated in this study, 30 were detected at least once

(table 4). In general, more pesticides were detected

as basin size increased (fig. 8). In the River Raisin

near Manchester, Mich. (the smallest basin sampled

at 132 mi2

), 14 pesticides were detected at least

once; 27 pesticides were detected at the Maumee

River at Waterville, Ohio (the largest basin at

6,330 mi2

). Exceptions to this trend were observed

at the pasture/forest sites, Cattaraugus Creek and

Grand River—basins in which fewer numbers

and smaller quantities of pesticides are applied

than in the row-crop basins in the study. Atrazine

(an herbicide used primarily on corn) was detected

in every sample, including samples from the basins

with relatively small amounts of row crops (less

than 10 percent) such as the Cattaraugus Creek and

Cuyahoga River Basins. Concentrations of atrazine

were much greater, however, in the row-crop basins

than in other basins. The atrazine degradate deethylatrazine and the herbicide metolachlor were

detected in 99 percent of the samples. Eight of the

Raisin

River

River

Clinton

River

Auglaize

Creek

Cattaraugus

River

Black

River

Grand

River

Joseph

St.

River

Cuyahoga

Haven

New

RiverMaumee

Waterville

RiverMaumee

0

30

10

20

NUMBER OF DETECTIONS

Figure 8. Number of pesticides detected in the Lake Erie-Lake St. Clair Basin, 1996–98.

Surface-water-sampling sites listed in order of increasing basin size.

47 pesticides analyzed
20 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98 Table 4. Frequency of detection and summary of pesticide concentrations for evaluated pesticides in the Lake Erie-Lake St. Clair 

[Pesticide degradates in bold were sampled only at the St. Joseph River near Newville, Ind.; μg/L, micrograms per liter; ESA, ethane sulfonic acid; OA, oxanilic and concentration estimated; nd, no detections; ld, less than detection limit; --, insufficient number of samples to calculate value]

Compound

Method detection

limit

(μg/L)

Number of samples

analyzed

Frequency of detection

(percent)

Median

(μg/L)

95th perce

(μg/L)

Acetochlor 0.002 305 58.0 0.009 2.57 Acetochlor ESA .20 10 90.0 .585 -- Acetochlor OA .20 10 70.0 .475 -- Alachlor .002 305 63.9 .011 1.28 Alachlor ESA .20 10 100 .665 -- Alachlor OA .20 10 70.0 .250 -- Atrazine .001 305 100 .134 14.0 Atrazine, deethyl .002 305 99.0 E .024 E .433 Atrazine, deisopropyl .05 10 80.0 .160 -- Atrazine, hydroxy .20 10 80.0 .580 -- Azinphos, methyl .001 302 0 nd nd Benfluralin .002 305 1.6 ld ld Butylate .002 305 1.6 ld ld Carbaryl .003 305 16.4 ld E .027 Carbofuran .003 305 3.6 ld ld Chlorpyrifos .004 301 21.6 ld .020 Cyanazine .004 305 70.5 .023 3.36 Cyanazine amide .05 10 60.0 .235 -- DCPA .002 302 11.9 ld .002 DDE, p,p’ .006 305 1.3 ld ld 

Diazinon .002 305 43.0 ld .063 Dieldrin .001 305 1.0 ld ld Diethylanaline-2,6 .003 305 1.0 ld ld Disulfoton .017 305 0 nd nd EPTC .002 305 7.5 ld .003 Ethalfluralin .004 305 0 nd nd 
Occurrence, Distribution, and Loads of Selected Pesticides 21

Table 4. Frequency of detection and summary of pesticide concentrations for evaluated pesticides in the Lake Erie-Lake St. Clair B

Compound

Method detection

limit

(μg/L)

Number of samples

analyzed

Frequency of detection

(percent)

Median

(μg/L)

95th percen

(μg/L)

Ethoprop 0.003 305 0 nd nd Fonofos .003 305 1.3 ld ld HCH, alpha .002 305 .3 ld ld HCH, gamma .004 305 0 nd nd Linuron .002 305 11.1 ld .049 Malathion .005 305 4.3 ld ld Metolachlor .002 305 99.3 .120 9.95 Metolachlor ESA .20 10 100 1.63 -- Metolachlor OA .20 10 100 .660 -- Metribuzin .004 305 49.5 ld 1.25 Molinate .004 305 0 nd nd Napropamide .003 305 0 nd nd Parathion .004 305 0 nd nd Parathion, methyl .006 305 .3 ld ld Pebulate .004 305 0 nd nd Pendimethalin .004 305 8.5 ld .021 Permethrin, cis .005 305 0 nd nd Phorate .002 305 0 nd nd Prometon .003 305 75.7 .013 .120 Pronamide .003 305 0 nd nd Propachlor .007 305 .3 ld ld Propanil .004 305 0 nd nd Propargite .013 305 0 nd nd Simazine .005 305 93.4 .026 .864 Tebuthiuron .010 305 25.9 ld .023 Terbacil .007 305 2.0 ld ld Terbufos .013 305 0 nd nd Thiobencarb .002 305 0 nd nd Triallate .001 305 0 nd nd Trifluralin .002 305 9.2 ld .003 
22 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

47 pesticides and degradates were detected in at

least 50 percent of the samples (table 4). All eight

of these are herbicides used on row crops, except

for prometon which is used primarily in urban

areas. Of the 15 most commonly used agricultural

pesticides evaluated in this study, all were detected

in at least 8.5 percent of the samples. Diazinon

and chlorpyrifos were the most frequently detected

insecticides—detected in 43 and 21.6 percent

of the samples, respectively. Additional data on

detection frequencies and other statistics for each

of the basins sampled are included in appendix B.

Seventeen of the 47 evaluated pesticides and

degradates were not detected (table 4). Of these,

nine had no reported agricultural use in the Basin.

Of the 17 evaluated insecticides, 9 were not

detected. The most heavily applied agricultural pesticide not detected was the insecticide ethoprop

(2,100 pounds applied annually).

Atrazine and metolachlor had the highest

detected concentrations in the Basin at 85 and

78 μg/L, respectively. All seven pesticides that

had the highest measured concentrations are rowcrop herbicides (either triazines or amides) and,

except for simazine, also are the seven most heavily

applied pesticides. As was noted previously, however, use of simazine probably is underreported in

the individual state statistics.

Spatial Distribution

The spatial distribution of pesticides in streams

coincides with the types and amounts of land uses

in basins. Many herbicides, such as atrazine, are

used exclusively or predominantly on row crops

while other pesticides, such as the herbicide prometon and the insecticide diazinon, usually are used

in urban areas. Most row-crop agriculture is in the

western section of the Lake Erie Basin, while land

use in easternmost section is primarily pasture

and forest. Only 17 pesticides were detected in

these eastern basins. At row-crop sites in western

Ohio, northeastern Indiana, and southeastern Michigan, 30 pesticides were detected—the same 30

pesticides that were detected in the entire Basin.

In the urban streams, 20 pesticides were detected.

The frequency of detections for certain pesticides also reflects the predominant land uses in

basins. Pesticides used primarily in urban areas,

such as diazinon or carbaryl, were detected up to

four times more frequently in urban basins than in

row-crop or pasture/forest basins (fig. 9). Prometon,

a non-selective herbicide, is used for total vegetation control mostly in urban areas, but it also is

used in agricultural areas (Capel and others, 1999).

It was detected in almost 75 percent of the samples in row-crop basins and in 90 percent of the

samples in urban basins. Herbicides used primarily

on row crops—such as acetochlor, alachlor, linuron, and metribuzin—were detected up to seven

times more often in row-crop basins than in urban

basins.

A comparison of atrazine and diazinon reflects

the relation between land use in a basin and the

frequency of detection and concentration of pesticides in streams (fig. 10). Atrazine had higher

concentrations in the row-crop basins than in the

urban or pasture/forest basins. Diazinon had higher

concentrations in the urban basins than in the rowcrop or pasture/forest basins.

Although atrazine and metolachlor were

detected in 99 to 100 percent of all samples, maximum measured and median concentrations were

higher in the row-crop basins. Likewise, concentrations of cyanazine and diazinon in an urban basin

(Clinton River) and a row-crop basin (Auglaize

River) reflect the differences between the land

uses in these basins. At the Auglaize River site,

maximum measured concentrations of 7 μg/L of

cyanazine (an herbicide used primarily on corn)

occurred in May and June (fig. 11, p. 24). At the

Clinton River, a peak occurred in May and June,

with a maximum measured concentration of

0.410 μg/L. The median concentration of cyanazine was higher in the Auglaize River at 0.095 μg/L

than in the Clinton River at 0.022 μg/L. Diazinon,

an insecticide used mostly in urban and residential

areas, had a higher maximum measured concentration in the Clinton River at 0.197 μg/L than in the

Auglaize River at 0.048 μg/L (fig. 11). Maximum

measured concentrations of diazinon occurred following application in late July to September at

both sites.
Occurrence, Distribution, and Loads of Selected Pesticides 23

0 100 20 40 60 80

ROW-CROP SITES

Acetochlor

Alachlor

Atrazine

Deethylatrazine

Carbaryl

Chlorpyrifos

Cyanazine

DCPA

Diazinon

Linuron

Metolachlor

Metribuzin

Prometon

Simazine

Tebuthiuron

0 100 20 40 60 80

PASTURE/FOREST SITES

0 100 20 40 60 80

URBAN SITES

0 100 20 40 60 80

ALL SITES

Acetochlor

Alachlor

Atrazine

Deethylatrazine

Carbaryl

Chlorpyrifos

Cyanazine

DCPA

Diazinon

Linuron

Metolachlor

Metribuzin

Prometon

Simazine

Tebuthiuron

Figure 9. Relation of frequency of detections for selected pesticides to primary land use in the Lake ErieLake St. Clair Basin, 1996–98.

no detections

(51) (125) (66)

PASTURE/ ROW CROP URBAN

0.001

1

0.002

0.005

0.01

0.02

0.05

0.1

0.2

0.5

CONCENTRATION, IN MICROGRAMS PER LITER

(52) (126) (65)

0.0005

200

0.001

0.01

0.1

1

10

100

Method detection limit

10th percentile

25th percentile

Median

75th percentile

90th percentile

10th and 90th percentiles

Data values outside the

(52) Number of observations

Figure 10. Concentrations of atrazine and diazinon in streams in pasture/forest, row-crop, and urban areas,

ATRAZINE

DIAZINON

FOREST

Lake Erie-Lake St. Clair Basin, 1996–98.

EXPLANATION
24 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

The spatial distribution of atrazine concentrations among the 10 surface-water-sampling sites

is similar to that of the most commonly used rowcrop herbicides. As shown in figure 12, in general,

atrazine concentrations are lower at the urban

sites (Clinton and Cuyahoga Rivers) and at the

pasture/forest sites (Grand River and Cattaraugus

Creek) than at the row-crop sites. Most row-crop

basins (Auglaize, St. Joseph, and both Maumee

River sites) have higher concentrations of atrazine.

The River Raisin, the one exception, has lower

atrazine concentrations than all other row-crop

sites. The relatively low concentrations of atrazine

in the River Raisin probably are because of (1) a

lower percentage of row crops than in the other

row-crop basins (table 2); (2) less surface runoff

(90 percent of streamflow comes from ground

water, which allows for more adsorption of the

pesticides to soils); (3) fewer tile drains; and

(4) more riparian buffer zones that hinder pesticide

transport by overland runoff into streams.

Some pesticides were detected locally in certain parts of the Basin. EPTC, a thiocarbamate

herbicide used on corn and beans, was detected

in 23 of the 315 samples; 65 percent of the detections were in the Black River near Manchester,

Mich. Even though DDT was banned from use in

the United States in 1973 because of human-health

and environmental concerns, a DDT degradate

(p,p’-DDE) was detected in four samples at low

concentrations; three detections were in the Black

River and all four detections occurred in Michigan.

Although reliable usage data are not available for

either pesticide, EPTC detections probably are

caused by recent use; p,p’-DDE detections probably are the result of historical use of DDT, its

0

8

2

4

6

Auglaize River

Clinton River

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

1996 1997 1998

0

0.25

0.05

0.10

0.15

0.20

 PESTICIDE CONCENTRATION, IN MICROGRAMS PER LITER

CYANAZINE

DIAZINON

Figure 11. Relation of cyanazine and diazinon concentrations to time for samples collected in streams

in an urban area (the Clinton River at Sterling Heights, Mich.) and in a row-crop area (the Auglaize

River near Fort Jennings, Ohio).
Occurrence, Distribution, and Loads of Selected Pesticides 25

Raisin

River

River

Clinton

River

Auglaize

Creek

Cattauragus

River

Black

River

Grand

River

Joseph

St.

River

Cuyahoga

Haven

New

RiverMaumee

Waterville

RiverMaumee

0.001

100

0.002

0.005

0.01

0.02

0.05

0.1

0.2

0.5

1

2

5

10

20

50

CONCENTRATION, IN MICROGRAMS PER LITER

EXPLANATION

10th percentile

25th percentile

Median

75th percentile

90th percentile

 10th and 90th percentiles

Data values outside the

Figure 12. Atrazine concentrations in the Lake Erie-Lake St. Clair Basin, 1996–98. Surface-water-sampling sites

Urban

Row crop

Pasture/forest

listed in order of increasing basin size.

sorption to sediments, and resuspension into the

streamwater. One blank also had a detection of

p,p’-DDE (discussed in appendix A, p. 55).

Temporal Variations

It has been well documented that highest concentrations of pesticides in streams occur when

precipitation causes surface-water runoff and tile

drains to transport recently applied pesticides into

streams (Richards and Baker, 1993; Fenelon and

Moore, 1998; Crawford, 1995; Larson and others,

1997). Most agricultural herbicides are applied

either as pre-emergent or early post-emergent in

the spring, and the corresponding highest concentrations in streams occur soon after application.

In the Lake Erie Basin, highest herbicide concentrations typically coincided with the first runoff

after application and then steadily decreased to

pre-application values. For some heavily used herbicides such as atrazine, metolachlor, cyanazine,

and acetochlor, elevated concentrations persisted

for 4 to 6 weeks after the initial maximum measured

concentration in the streams in row-crop basins.

A typical seasonal pattern for agricultural herbicides applied in the spring is shown in a graph of

atrazine concentrations in the St. Joseph River near

Newville, Ind. (fig. 13A). Maximum measured

concentrations of prometon occurred in late summer (fig. 13B); some herbicides that primarily are

used in urban areas, such as prometon, commonly

are applied in late summer or early fall. Some insecticides primarily used in urban areas, such as

diazinon, are applied over a longer period that can

extend from late spring to late summer. A typical

seasonal pattern for insecticides commonly used in

urban areas is shown in a graph of diazinon concentrations in the Clinton River at Sterling Heights,

Mich. (fig. 13C).
26 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

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

1996 1997 1998

0

25

5

10

15

20

0

10,000

2,000

4,000

6,000

8,000 STREAMFLOW

PESTICIDE DETECTED

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

1996 1997 1998

0

0.25

0.05

0.10

0.15

0.20

STREAMFLOW, IN CUBIC FEET PER SECOND

0

2,500

500

1,000

1,500

2,000

PESTICIDE CONCENTRATION, IN MICROGRAMS PER LITER

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

1996 1997 1998

0

0.25

0.05

0.10

0.15

0.20

0

2,500

500

1,000

1,500

2,000

ATRAZINE

PROMETON

DIAZINON

A

B

C

Figure 13. Relation of selected pesticide concentrations and streamflow to time, (A) atrazine in the 

St. Joseph River near Newville, Ind.; (B) prometon in the Clinton River at Sterling Heights, Mich.;

and (C) diazinon in the Clinton River at Sterling Heights, Mich. 
Occurrence, Distribution, and Loads of Selected Pesticides 27

Degradates of Selected Herbicides

Typically, only 0.01 to 10 percent of the mass

of pesticide compounds applied to fields is detected

in streams (Larson and others, 1999). The remaining 90 to 99 percent of pesticides adsorb to soil,

percolate into ground water, or volatilize (Larson

and others, 1997). The major degradates of the most

heavily used herbicides found in surface water have

not been studied widely. It is believed, however, that

some degradates are as toxic or more toxic than the

parent compound (Day, 1991).

Many physical properties of pesticides affect

the amount transported to streams but, in general,

acetanilide herbicides are more soluble in water

and thus more mobile than the triazines (Crawford,

2001). The solubility of sulfonated degradates

of acetanilides (ethane sulfonic acid—ESA), can

be 10 times the solubility of the parent (Thurman

and others, 1996). The greater mobility of the

degradates of the acetanilides (amide family) can

explain their greater frequency of detection and

concentrations when compared to the triazines in

the 10 samples from the St. Joseph River site. The

frequency of detection of degradates ranged from

60 percent (6 of 10 samples) for cyanazine amide

to 100 percent (10 of 10 samples) for metolachlor

degradates (table 4). Acetochlor ESA, acetochlor

oxanilic acid, and cyanazine amide had maximum

measured concentrations greater than 4 μg/L;

acetochlor oxanilic acid had the highest maximum

measured concentration of 6.76 μg/L.

Concentrations of the triazine and acetanilide

degradates had seasonal trends similar to their

parent compounds (fig. 14). The greatest concentrations of the degradates detected in the 10 samples

from the St. Joseph River were in the samples

collected in the spring after the first rains following

application of pesticides. The maximum measured

concentrations of the degradates, however, were

in samples collected from 1 to 2 weeks after the

maximum measured concentration of the parent

compound. After the maximum concentration was

measured, degradate and parent compound concentrations steadily decreased to detection levels for

the triazines. For the acetanilides, the degradate

concentrations also decreased with time. Concentrations of acetanilide degradates, however, were

higher than that of the parent compound for most

of the year (except immediately after application).

Acetanilide degradates constituted a much larger

fraction of the total acetanilide herbicides washing

off fields than triazine degradates did for triazine

herbicides. These limited data suggest that degradates (especially of acetanilide herbicides) can

contribute a significant proportion of the pesticide

load to Lake Erie. This pattern is similar to results

found in Iowa (Kalkhoff and others, 1998).

Relation to Drinking-Water Standards

or Guidelines and Aquatic-Life Guidelines

Although the use of pesticides has increased

agricultural productivity significantly and has

helped to limit disease transmission by insects,

many pesticides can have carcinogenic, mutagenic,

or other toxic effects on humans and aquatic life.

Recently, for example, some pesticides were linked

to endocrine disruption in some species (Goodbred

and others, 1997; Smith, 1998).

To protect the health of human and aquatic

life, enforceable standards and advisory guidelines

have been set by several agencies, including the

U.S. Environmental Protection Agency (USEPA),

Environment Canada, and the International Joint

Commission (IJC). In this report, observed and

time-weighted average concentrations are compared to USEPA standards and guidelines if they

exist, or to Canadian or IJC values. The USGS

NAWQA Program is designed to assess the quality

of the Nation’s water resources; it is not designed

to monitor drinking-water quality. Comparisons

made in this report to drinking-water standards and

guidelines are made in the context of the available

untreated (raw) resource (U.S. Geological Survey,

1999).

In the United States, the USEPA sets the primary drinking-water regulations to protect human

health (U.S. Environmental Protection Agency,

2000). Maximum Contaminant Levels (MCL’s)

are the maximum permissible concentration of a

contaminant in water that is delivered to any user

of public water systems; they are established on the

basis, among other factors, of health effects, feasibility and cost of water treatment, and analytical
28 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

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

1997 1998

0

20

2

4

6

8

10

12

14

16

18

0

5,000

1,000

2,000

3,000

4,000

Streamflow

Atrazine

Atrazine, deethyl

Atrazine, deisopropyl

Atrazine, hydroxy

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

1997 1998

0

2.5

0.5

1.0

1.5

2.0

STREAMFLOW, IN CUBIC FEET PER SECOND

0

5,000

1,000

2,000

3,000

4,000

PESTICIDE CONCENTRATION, IN MICROGRAMS PER LITER

Streamflow

Alachlor

Alachlor ethane sulfonic acid

Alachlor oxanilic acid

ATRAZINE

ALACHLOR

Figure 14. Relation of the triazine compound atrazine, the acetanilide alachlor, and selected degradate concentrations and streamflow to time in the St. Joseph River near Newville, Ind.
Occurrence, Distribution, and Loads of Selected Pesticides 29

detection limits (Nowell and Resek, 1994). MCL’s

are enforceable standards, and a water-treatment

facility’s compliance with these standards is based

on an average concentration of four quarterly samples of treated (finished) drinking water. Of the 47

pesticides and degradates evaluated in this study,

MCL’s have been set for five: alachlor, atrazine,

carbofuran, lindane, and simazine (table 5). No

MCL has been established for acetochlor, but

an annual time-weighted average benchmark of

2.0 μg/L has been suggested as part of a conditional

registration (“REG” in table 5).

For some pesticides, the USEPA also sets

nonenforceable drinking-water health advisories.

These guidelines represent concentrations that are

expected to result in no adverse noncarcinogenic

acute (1- and 10-day, child), longer-term (7-year,

child and adult), and lifetime (70-year, adult)

human-health effects. For health advisories to be

exceeded, a child would need to drink 1 L per day

or an adult would need to drink 2 L per day of water

at the guideline concentration for the length of the

specific time period (1 day, 10 days, 7 years, or

70 years). Drinking-water health advisories—but

no MCL’s—have been set for 20 of the pesticides

evaluated in this study (table 5).

For some pesticides, the USEPA also sets

nonenforceable risk-specific dose (RSD) guidelines

that are associated with some degree of cancer risk.

For example, an RSD5 represents a risk of 1 in

100,000 for a concentration in drinking water equal

to the RSD. In other words, the lifetime consumption of drinking water with a concentration equal

to the RSD would result in an upper-bound excess

cancer risk of 1 in 100,000. Of the 47 pesticides and

degradates monitored, RSD guidelines have been

set for 5: alachlor, alpha-HCH, p,p’-DDE, dieldrin,

and trifluralin.

For some pesticides, nonenforceable guidelines have been set to prevent long- and short-term

effects on aquatic life. The USEPA aquatic-life

guidelines are based upon 4-day average concentrations, are intended to protect 95 percent of the

aquatic species, and are not to be exceeded more

than once in 3 years. Canadian and IJC aquaticlife guidelines, which are more stringent than

those of the USEPA, indicate a single maximum

measured concentration that should never be

exceeded. Of the 47 pesticides or degradates

analyzed, aquatic-life guidelines for 18 have been

set by either the USEPA, Environment Canada, or

the IJC.

Several researchers have noted the limitations

of available standards and guidelines as a basis

for evaluating the potential effects of pesticides in

surface water (Nowell and Resek, 1994; Larson

and others, 1999). These limitations include

(1) Standards and guidelines have not

been set for many pesticides. Of

the 47 pesticides evaluated, only 5

MCL’s, 25 drinking-water health

advisories, and 18 aquatic-life guidelines have been set.

(2) Few standards and guidelines have

been set for pesticide degradates.

Degradates, especially of the acetanilides such as metolachlor and alachlor

were detected frequently and at

greater concentrations than the parent

compound.

(3) Standards and guidelines are established on the basis on toxicity tests

that are conducted on a single pesticide and that do not evaluate the

possible additive or synergistic effects

of multiple pesticides. Of the 47 pesticides and degradates monitored in

this study, 27 were detected in the

Maumee River at Waterville, Ohio,

at least once, and up to 19 pesticides

were detected in a single sample.

(4) Aquatic-life guidelines do not account

for the effects of multiple stressors

in concert with pesticides such as

suspended sediment, low dissolved

oxygen, or inorganic contaminants.

(5) Standards and guidelines do not

address possible effects of pesticides

on the endocrine systems of humans

(Colborn and others, 1993) and

aquatic organisms (Goodbred

and others, 1997).
30 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98 Table 5. Human-health and aquatic-life benchmarks established for evaluated compounds (RSD5, risk-specific dose associated with an excess cancer risk of 1 in 100,000 for a concentration in drinking water equal to the RSD; μg/L, microgram per l

U.S. Environmental Protection Agency; MCL, U.S. Environmental Protection Agency–established Maximum Contaminant Level for drinking water; --, no stadian guideline for protection of aquatic life; USEPA, U.S. Environmental Protection Agency; CAN-INT, Canadian interim guideline for protection of aquatic lfrom the International Joint Commission] Human-health standards and guidelinesa 

Primary drinking-water standard Drinking-water health advisories 

Compound Number of samples Value

(μg/L) Source

1 and 10 day,

child value

(μg/L)

Longer term,

child valueb

(μg/L)

Longer term,

adult value

(μg/L)

Lifetime,

adult value

(μg/L)

RS

a

1 in 

can

ri

(μg

Acetochlor 305 2.0 REG 8.0 -- -- -- -Alachlor 305 2.0 MCL 100 -- -- -- 4Atrazine 305 3.0 MCL 100 50 200 3.0 -Atrazine, deethyl 305 -- -- -- -- -- -- -Azinphos, methyl 302 -- -- -- -- -- -- -Benfluralin 305 -- -- -- -- -- -- -Butylate 305 -- -- 2,000 1,000 4,000 350 -Carbaryl 305 -- -- 1,000 1,000 1,000 700 -Carbofuran 305 40 MCL 50 50 200 40 -Chlorpyrifos 301 -- -- 30 30 100 20 -Cyanazine 305 -- -- 100 20 70 1.0 -DCPA 302 -- -- 80,000 5,000 20,000 -- -DDE, p,p’ 305 -- -- -- -- -- -- 1Diazinon 305 -- -- 20 5 20 .6 -Dieldrin 305 -- -- .5 .5 2 -- Diethylaniline -2,6 305 -- -- -- -- -- -- -Disulfoton 305 -- -- 10 3 9 .3 -EPTC 305 -- -- -- -- -- -- -Ethalfluralin 305 -- -- -- -- -- -- -Ethoprop 305 -- -- -- -- -- -- -Fonofos 305 -- -- 20 20 70 10 -
Table 5. Human-health and aquatic-life benchmarks established for target compounds—Continued

Occurrence, Distribution, and Loads of Selected Pesticides 31

HCH, alpha 305 -- -- -- -- -- -- 0.0HCH, gamma 305 .2 MCL 1,000 30 100 .2 -- Linuron 305 -- -- -- -- -- -- -- Malathion 305 -- -- 200 200 800 200 -- Methyl parathion 305 -- -- 300 30 100 2.0 -- Metolachlor 305 -- -- 2,000 2,000 5,000 70 -- Metribuzin 305 -- -- 5,000 300 500 100 -- Molinate 305 -- -- -- -- -- -- -- Napropamide 305 -- -- -- -- -- -- -- Parathion 305 -- -- -- -- -- -- -- Pebulate 305 -- -- -- -- -- -- -- Pendimethalin 305 -- -- -- -- -- -- -- Permethrin, cis 305 -- -- -- -- -- -- -- Phorate 305 -- -- -- -- -- -- -- Prometon 305 -- -- 200 200 500 100 -- Pronamide 305 -- -- 800 800 3,000 50 -- Propachlor 305 -- -- 500 100 500 90 -- Propanil 305 -- -- -- -- -- -- -- Propargite 305 -- -- -- -- -- -- -- Simazine 305 4.0 MCL 70 70 70 4.0 -- Tebuthiuron 305 -- -- 3,000 700 2,000 500 -- Terbacil 305 -- -- 300 300 900 90 -- Terbufos 305 -- -- 5 1 5 .9 -- Thiobencarb 305 -- -- -- -- -- -- -- Triallate 305 -- -- -- -- -- -- -- Trifluralin 305 -- -- 80 80 300 5.0 50 

aValues taken from http://infotrek.er.usgs.gov/wdbctx/nawqa_www/NWQ_MNG.STDS_REPORT.html on August 30, 2000.bIntended to represent 10 percent of a lifetime or 7 years.

Human-health standards and guidelinesa 

Primary

drinking-water

standard

Drinking-water

health advisories

Compound

Number

of

samples

Value

(μg/L) Source

1 and 10 day,

child value

(μg/L)

Longer term,

child valueb

(μg/L)

Longer term,

adult value

(μg/L)

Lifetime,

adult value

(μg/L)

RSD

at

1 in 1

canc

risk

(μg/
32 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

An Ohio Environmental Protection Agency

report noted that at no drinking-water-treatment

facility in Ohio did annual average pesticide concentrations exceed the primary drinking-water

standards (MCL’s) from 1995 to 1999 (Kelleher,

1999). Four of the surface-water-sampling sites in

this study are either near drinking-water intakes or

in a stream used as a source of drinking water: the

Auglaize River near Fort Jennings, Ohio; St. Joseph

River near Newville, Ind.; Maumee River at New

Haven, Ind.; and the Maumee River at Waterville,

Ohio. MCL’s apply to treated water. Although the

data collected in this study are from stream samples, they provide temporal and spatial information

on pesticide concentrations in raw water used for

public supply in the Lake Erie Basin.

The elevated concentrations of pesticides

observed during spring runoff has economic as

well as health consequences for areas that use

surface water as a source for drinking water. Many

larger water-treatment facilities that use surface

water (other than Lake Erie) use activated carbon

during the spring to meet drinking-water standards.

In areas where pesticides are applied heavily, some

facilities use activated carbon all year to remove

pesticides. The annual cost of this treatment is

approximately $210,000; about 40 percent of this

cost is incurred during April to July (Doug Pooler,

Fort Wayne Water Filtration Plant, oral commun.,

1999). Moreover, despite carbon treatment, some

individual samples collected by the treatment

facilities during the spring exceeded the MCL

for atrazine, although the annual average concentrations did not exceed the MCL.

Annual time-weighted average concentrations

and time-weighted average concentrations of

selected pesticides for May through July were calculated at all surface-water-sampling sites, using

data collected from March 1, 1996, to February 28,

1998 (table 6). No annual time-weighted average

concentrations exceeded the MCL for pesticides

with established MCL’s. During May through July,

however, when pesticide runoff into streams is

greatest, time-weighted average concentrations

would meet or exceed the MCL for atrazine of

3.00 μg/L at five row-crop sites: Maumee River at

New Haven (10 μg/L), Maumee River at Waterville

(9.26 μg/L), Auglaize River (8.87 μg/L), St. Joseph

River (5.45 μg/L), and Black River (3.00 μg/L).

No other time-weighted average concentrations for

pesticides with an established MCL were exceeded

May through July.

No annual time-weighted average concentrations exceeded the acute, longer-term, or lifetime

health advisories (table 6). The time-weighted

average concentrations of atrazine and cyanazine,

however, frequently exceeded lifetime adult

health advisories (HA-L) during May through

July.

Chronic aquatic-life guidelines were exceeded

for atrazine, metolachlor, cyanazine, metribuzin,

diazinon, chlorpyrifos, and carbaryl. The heavily

used row-crop herbicides atrazine, metolachlor,

cyanazine, and metribuzin had the largest number

of exceedences of these guidelines; diazinon had

the highest number of exceedences of any insecticide. One or more aquatic-life guidelines were

exceeded at least once in every stream except the

River Raisin and Cattaraugus Creek. The number

of exceedences did not increase with stream size;

instead, the type of land use in the basin was more

of a factor in determining the number of exceedences. Samples from the row-crop basins had the

highest number of exceedences of aquatic-life

guidelines: the Auglaize River had the highest at

27 exceedences, followed by the Maumee River

at Waterville, the St. Joseph River, the Maumee

River at New Haven, and the Black River (fig. 15,

p. 34). Most of the exceedences at these sites were

because of high concentrations of row-crop herbicides, while exceedences of aquatic-life guidelines

in urban basins were mostly because of high concentrations of diazinon and chlorpyrifos.

Exceedences of aquatic-life guidelines may

impact fish communities in the Lake Erie Basin.

One component of the NAWQA Program is the

collection of biological samples to help determine

water quality; the fish community and instream

and riparian habitat at the sampled sites were

studied. Most of the surface-water-sampling sites

in this study have good to excellent fish habitat

based upon Qualitative Habitat Evaluation Index

(QHEI) scores (Ohio Environmental Protection

Agency, 1989). The fish communities, however,
Occurrence, Distribution, and Loads of Selected Pesticides 33

aCalculated using 2 years of data from March 1, 1996, to February 28, 1998.

Site name

Acetochlor Alachlor Atrazine Cya

Drainage

area

(mi2)

Timeweighted

average

(μg/L)a

Timeweighted

average

May–July

(μg/L)

Timeweighted

average

(μg/L)

Timeweighted

average

May–July

(μg/L)

Timeweighted

average

(μg/L)

Timeweighted

average

May–July

(μg/L)

Timeweighted

average

(μg/L)

River Raisin near Manchester, Mich. 132 0.006 0.019 0.004 0.012 0.037 0.090 0.010 

Clinton River at Sterling Heights, Mich. 309 .012 .040 .005 .015 .038 .084 .007 Auglaize River near Fort Jennings, Ohio 332 .205 .759 .268 .997 2.41 8.87 .458 Cattaraugus Creek at Gowanda, N.Y. 436 .002 .002 .004 .010 .036 .111 .005 Black River near Jeddo, Mich. 464 .190 .709 .097 .327 .905 3.00 .232 Grand River at Harpersfield, Ohio 552 .038 .106 .012 .041 .527 1.29 .022 St. Joseph River near Newville, Ind. 610 .331 1.28 .247 .912 1.58 5.45 .358 Cuyahoga River at Cleveland, Ohio 788 .015 .048 .005 .010 .098 .243 .016 Maumee River at New Haven, Ind. 1,967 .470 1.83 .254 .928 2.75 10 .511 Maumee River at Waterville, Ohio 6,330 .500 1.93 .349 1.31 2.57 9.26 .747 

Site name

Simazine Chlorpyrifos Diazinon Pro

Drainage

area

(mi2)

Timeweighted

average

(μg/L)

Timeweighted

average

May–July

(μg/L)

Timeweighted

average

(μg/L)

Timeweighted

average

May–July

(μg/L)

Timeweighted

average

(μg/L)

Timeweighted

average

May–July

(μg/L)

Timeweighted

average

(μg/L)

River Raisin near Manchester, Mich. 132 0.101 0.220 0.004 0.004 0.003 0.004 0.015 

Clinton River at Sterling Heights, Mich. 309 .019 .030 .005 .005 .029 .024 .040 Auglaize River near Fort Jennings, Ohio 332 .180 .617 .007 .013 .006 .013 .050 Cattaraugus Creek at Gowanda, N.Y. 436 .013 .040 .004 .004 .002 .002 .016 Black River near Jeddo, Mich. 464 .017 .036 .005 .005 .004 .003 .014 Grand River at Harpersfield, Ohio 552 .033 .086 .007 .015 .010 .007 .018 St. Joseph River near Newville, Ind. 610 .131 .220 .012 .034 .002 .003 .028 Cuyahoga River at Cleveland, Ohio 788 .019 .041 .009 .017 .045 .081 .043 Maumee River at New Haven, Ind. 1,967 .191 .654 .017 .046 .023 .028 .064 Maumee River at Waterville, Ohio 6,330 .194 .677 .013 .024 .007 .014 .037 

Table 6. Two-year time-weighted average concentrations and time-weighted May through July average concentrations for selected 

sampling sites in the Lake Erie-Lake St. Clair Basin, 1996–98

[Concentrations in bold exceeded a human-health or aquatic-life benchmark; mi2, square mile; μg/L, microgram per liter]
34 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

have only poor to good Index of Biological Integrity (IBI) values (Ohio Environmental Protection

Agency, 1987). Two sites that had low numbers

of exceedences of aquatic-life guidelines (Grand

River and the River Raisin) also had IBI values

that ranked “good,” whereas the four sites with the

highest number of exceedences (Auglaize River,

St. Joseph River, and both Maumee River sites) had

IBI values that ranked “poor” (Stephen Rheaume,

U.S. Geological Survey, oral commun., 1999). Similar results were found in the White River Basin in

Indiana (Frey and others, 1996).

The USEPA aquatic-life guidelines specify a

recurrence interval of 3 years, which implies that an

aquatic ecosystem can recover if the contaminant

concentration does not exceed the guideline more

than once in 3 years (Larson and others, 1999).

This study found that concentrations of pesticides

commonly associated with a specific land use in

the Lake Erie Basin exceeded the aquatic-life

guidelines at least once from 1996 to 1998. In the

row-crop basins, guidelines were exceeded by

atrazine, cyanazine, metolachlor, and metribuzin;

in the urban basins by diazinon and chlorpyrifos.

Drinking-water standards, human-health

advisories, or aquatic-life guidelines have not

been established for acetochlor. As a requirement of conditional registration in 1994, however,

restrictions regarding concentration levels of acetochlor in drinking water were established by the

USEPA (U.S. Environmental Protection Agency,

1994). Those restrictions apply if the annual timeweighted average concentration of acetochlor

exceeds 2.00 μg/L in one or more community water

supplies that derive water primarily from surface

water. These restrictions range from prohibiting

the use of acetochlor in the affected watershed to

cancellation of the registration if the exceedences

are widespread. For example, a single measured

concentration of 8.0 μg/L in a community water

supply deriving its water primarily from surface

water would result in a requirement for additional

monitoring.

The annual time-weighted average concentrations of acetochlor in the four surface-watersampling sites in this study that are near a public

water intake or are used as a public water supply

did not exceed 2.00 μg/L. The highest calculated

annual time-weighted average acetochlor concentration was 0.500 μg/L for the Maumee River at

Waterville, Ohio. Individual concentrations of

acetochlor in samples exceeded 8.00 μg/L twice—

once in the Maumee River at New Haven, Ind.,

Auglaize River

Waterville

Maumee RiverSt. Joseph River

New Haven

Maumee RiverBlack River

Cuyahoga River

Grand River

Clinton River

River Raisin

Creek

Cattaraugus

0

30

10

20

NUMBER OF EXCEEDENCES

PRIMARY LAND USE

Row crop

Urban

Pasture/forest

Figure 15. Number of times U.S. Environmental Protection

Agency aquatic-life guidelines were exceeded, by site, in

the Lake Erie-Lake St. Clair Basin, 1996-98. (There were

no exceedences for River Raisin, which is primarily row crop,

and Cattaraugus Creek, which is primarily pasture/forest.)
Occurrence, Distribution, and Loads of Selected Pesticides 35

(8.88 μg/L) and once in the Maumee River at

Waterville, Ohio (11.0 μg/L). Both exceedences

occurred in May 1997.

Loads and Yields of Selected Pesticides

in Streams of Lake Erie

Public officials and water-resource managers

often need to know the amount of a contaminant

transported in a stream to determine the stream’s

condition and how it has changed over time. Loads

and yields of the contaminants are common measures for these assessments. Loads and yields were

calculated for selected pesticides for each basin on

the basis of 2 years of data collected from March

1996 to February 1998 (table 7). Application

estimates were based on county-level data for pesticides applied to corn and soybeans collected as

part of the Census of Agriculture in 1997 (National

Agricultural Statistics Service, 1999). Sufficient

data were available for estimating application of

pesticides used primarily on corn or soybeans (or

both), such as alachlor, acetochlor, atrazine, and

metolachlor. For other pesticides, use estimates

were unreliable (chlorpyrifos) or unavailable (diazinon and prometon).

Atrazine and metolachlor had the highest estimated use and the highest estimated loads. Loads

were less for insecticides and herbicides that have

primarily nonagricultural uses. For example, the

loads of chlorpyrifos and prometon in the Maumee

River at Waterville were only 0.3 and 0.6 percent,

respectively, of the atrazine load.

Estimated annual loads of commonly used

agricultural herbicides in the Maumee River at

Waterville for the study period were about 3 to

7 percent of that applied in the basin. Smaller

basins tended to have a higher percentage of the

amount of applied pesticide exported from the basin

than did larger basins. For example, 10.6 percent

of the atrazine applied in the St. Joseph River near

Newville was exported, compared to 7.1 percent

in the Maumee River at New Haven and 4.4 percent in the Maumee River at Waterville (table 8,

p. 39). Relatively high percentages also were found

in other small, predominantly row-crop basins (the

Auglaize River and the Black River). A notable

exception was the River Raisin Basin, where less

than 0.1 percent of the amount of atrazine applied

to cropland in that basin was detected. This may

be because of (1) the high percentage of permeable

soils in the basin and (2) streamflow contribution

by ground water (90 percent).

Pesticide loads in streams as a percentage

of the applied amount reported in this study are

higher than those found in earlier studies in the

Lake Erie Basin and in other basins in the United

States. Richards and others (1996) reported 0.1 to

4.0 percent loads for streams tributary to Lake Erie

in 1983 through 1993. Goolsby and Pereira (1995)

reported that loads of pesticides in major tributaries to the Mississippi River in the early 1990’s

were generally less than 3 percent of the amount

applied to cropland. Crawford (1995) reported

that loads of alachlor, atrazine, cyanazine, and

metolachlor in the 11,305-mi2 White River Basin

in Indiana were 0.2 to 1.3 percent of the amount

applied in 1992 through 1994. Percentages in this

Lake Erie study ranged from 0.1 to 10.6. It is not

known if the higher percentages found in this Lake

Erie study are because of regional differences in

soils, geology, or other natural factors or because

of differences in rainfall or other factors that vary

temporarily.

Annual pesticide loads reported for the Maumee River at Waterville, Ohio, by Richards and

others (1996) are less than those estimated in

this study. For example, the loads of atrazine and

metolachlor for 1983 through 1993 reported by

Richards and others (1996) were 78 and 54 percent,

respectively, of those found in this study. As noted

previously, however, precipitation and streamflow

during the study period were above normal. The

higher runoff during the period of this study is

the likely cause of the increased pesticide loads.

Unusually high runoff was probably also the cause

for the high pesticide loads detected in the White

River in Indiana in 1996 and 1997 (Charles G.

Crawford, U.S. Geological Survey, written commun., 1999). Annual loads for atrazine in the
Table 7. Estimated pesticide application in 1997 and summary of loads and yields calculated March 1996 to February 1998 per drainage area 

Lake St. Clair Basin surface-water-sampling sites

[mi2, square mile; lb/yr, pound per year; lb/mi2/yr, pound per square mile per year; -- , insufficient number of detections to determine loads and yields; nd, no data]

Site name

Acetochlor Alachlor 

Drainage

area

(mi2)

Estimated

amount

of

pesticide

applied

to

corn

and

soybeans

in 1997a

(pounds)

Load

(lb/yr)

Standard

deviation

of

load

(lb/yr)

Yield

per

drainage

areab

(lb/mi2/yr)

Estimated

amount

of

pesticide

applied

to

corn

and

soybeans

in 1997a

(pounds)

Load

(lb/yr)

Standard

deviation

of

load

(lb/yr)

Yield

per

drainage

areab

(lb/mi2/yr)

Est

am

pes

ap

c

a

soy

in 

(po

River Raisin near Manchester, Mich. 132 5,200 2.0 0.66 0.02 400 1.5 0.40 0.01 1Clinton River at Sterling Heights, Mich. 309 1,200 13 7.7 .04 100 5.1 1.6 .02 Auglaize River near Fort Jennings, Ohio 332 22,000 660 550 2.0 6,600 620 510 1.9 5Cattaraugus Creek at Gowanda, N.Y. 436 nd -- -- -- nd -- -- -- Black River near Jeddo, Mich. 464 12,000 260 260 .55 800 110 88 .24 2Grand River at Harpersfield, Ohio 552 7,600 84 73 .15 1,400 27 14 .05 1St. Joseph River near Newville, Ind. 610 34,000 11,000 14,000 17 6,200 1,600 1,400 2.6 7Cuyahoga River at Cleveland, Ohio 788 7,000 140 950 .18 1,500 37 15 .05 1Maumee River at New Haven, Ind. 1,967 120,000 6,600 5,500 3.3 26,000 2,900 2,200 1.5 31Maumee River at Waterville, Ohio 6,330 420,000 12,000 6,600 1.9 110,000 8,000 4,000 1.3 1,10
Table 7. Estimated pesticide application in 1997 and summary of loads and yields calculated March 1996 to February 1998 per drainage area o

Lake St. Clair Basin surface-water-sampling sites—Continued

Site name

Cyanazine Metolachlor 

Drainage

area

(mi2)

Estimated

amount

of

pesticide

applied

to

corn

and

soybeans

in 1997a

(pounds)

Load

(lb/yr)

Standard

deviation

of

load

(lb/yr)

Yield

per

drainage

areab

(lb/mi2/yr)

Estimated

amount

of

pesticide

applied

to

corn

and

soybeans

in 1997a

(pounds)

Load

(lb/yr)

Standard

deviation

of

load

(lb/yr)

Yield

per

drainage

areab

(lb/mi2/yr)

Estim

amo

of

pesti

appl

to

cor

an

soybe

in 19

(poun

River Raisin near Manchester, Mich. 132 1,900 3.0 0.91 0.02 12,000 2.7 0.37 0.02 nd Clinton River at Sterling Heights, Mich. 309 500 6.6 .99 .02 2,900 11 3.4 .03 nd Auglaize River near Fort Jennings, Ohio 332 26,000 730 510 2.2 71,000 5,500 2,900 16 5,6Cattaraugus Creek at Gowanda, N.Y. 436 nd -- -- -- nd -- -- -- nd Black River near Jeddo, Mich. 464 4,300 240 180 .53 30,000 2,200 1,800 4.7 nd Grand River at Harpersfield, Ohio 552 8,800 27 13 .05 18,000 220 130 .39 1,9

St. Joseph River near Newville, Ind. 610 25,000 2,200 1,500 3.6 92,000 7,300 6,200 12 3,2Cuyahoga River at Cleveland, Ohio 788 8,100 77 26 1.0 18,000 110 62 .13 1,7Maumee River at New Haven, Ind. 1,967 100,000 4,400 2,600 2.2 330,000 24,000 11,000 12 11,0Maumee River at Waterville, Ohio 6,330 440,000 15,000 7,700 2.4 1,300,000 44,000 15,000 6.9 79,0
Table 7. Estimated pesticide application in 1997 and summary of loads and yields calculated March 1996 to February 1998 per drainage area o

Lake St. Clair Basin surface-water-sampling sites—Continued

aFrom National Agricultural Statistics Service, 1999.bCalculated using square miles of drainage area.

Site name

Chlorpyrifos Diazinon 

Drainage

area

(mi2)

Estimated

amount

of

pesticide

applied

to

corn

and

soybeans

in 1997a

(pounds)

Load

(lb/yr)

Standard

deviation

of

load

(lb/yr)

Yield

per

drainage

areab

(lb/mi2/yr)

Estimated

amount

of

pesticide

applied

to

corn

and

soybeans

in 1997a

(pounds)

Load

(lb/yr)

Standard

deviation

of

load

(lb/yr)

Yield

per

drainage

areab

(lb/mi2/yr)

Estima

amou

of

pestic

appli

to

cor

and

soybe

in 199

(poun

River Raisin near Manchester, Mich. 132 700 -- -- -- nd 1.1 0.15 0.01 nd Clinton River at Sterling Heights, Mich. 309 200 3.5 .73 .01 nd 13 3.5 .04 nd Auglaize River near Fort Jennings, Ohio 332 5,600 12 4.4 .04 nd 14 3.7 .04 nd Cattaraugus Creek at Gowanda, N.Y. 436 nd -- -- -- nd -- -- -- nd Black River near Jeddo, Mich. 464 1,500 -- -- -- nd - -- -- nd Grand River at Harpersfield, Ohio 552 1,900 -- -- -- nd 30 19 .05 nd 

St. Joseph River near Newville, Ind. 610 5,800 40 25 .07 nd -- -- -- nd Cuyahoga River at Cleveland, Ohio 788 1,700 40 6.6 .05 nd 200 95 .26 nd Maumee River at New Haven, Ind. 1,967 20,000 110 55 .06 nd 320 300 .16 nd Maumee River at Waterville, Ohio 6,330 91,000 160 37 .02 nd 120 23 .02 nd 
Occurrence, Distribution, and Loads of Selected Pesticides 39

White River in 1996 through 1997 were as much

as 600 percent higher than the smallest load that

occurred during 1992 through 1998. As in the Lake

Erie Basin, precipitation and streamflow were

above normal in the White River Basin during 1996

through 1997.

Yields are loads normalized to a unit area;

for this report, loads are normalized by the amount

of drainage area. Because yields minimize the

influence of differences in streamflow, they

are useful measures for identifying streams that

export more pesticides. The St. Joseph and

Auglaize Rivers had the highest yields of commonly used row-crop herbicides (acetochlor,

alachlor, atrazine, cyanazine, metolachlor, and

simazine). Atrazine yields were 14 lb/mi2

/yr for

both of these streams (table 7); metolachlor yields

were 12 and 16 lb/mi2

/yr, respectively. The Cuyahoga River, an urban site, had the highest yields of

the pesticides that more typically are used in urban

areas (diazinon and prometon). Of these, diazinon

had the highest yield (0.26 lb/mi2/yr).

Relation of Pesticide Occurrence

to Pesticide Properties, Pesticide Use,

and Environmental Factors

Pesticide Properties

The chemical and physical properties of pesticides affect their behavior in the environment.

Panshin and others (1998) investigated the influence of some of these properties on the occurrence

and distribution of pesticides in the San Joaquin

Basin in California. Two variables associated

with the physical and chemical properties of

pesticides—runoff potential and pesticide family—

also are analyzed in this report. These properties

are identified in the plots of pesticides applied

versus the frequency of detection to compare general tendencies of these pesticides (table 3). A

pesticide’s runoff potential is based on its solubility

in water, soil half-life, and the normalized organiccarbon adsorption coefficient (Koc) and indicates

the likelihood the pesticide will be transported to

surface water (Goss, 1992).

Table 8. Drainage area, estimated atrazine application in 1997, atrazine load, and percentage of applied atrazine

exported at Lake Erie-Lake St. Clair Basin surface-water-sampling sites, 1996–98

[mi2, square mile; nd, no data]

Site name

Drainage

area

(mi2)

 Atrazine,

estimated applicationa

in 1997

(pounds of

active ingredient)

a

Estimated from county level data collected by National Agricultural Statistics Service, 1999.

Atrazine,

load

(pounds/year)

Percentage

of

applied atrazine

detected in stream

River Raisin near Manchester, Mich. 132 10,400 8.4 0.10

Clinton River at Sterling Heights, Mich. 309 2,500 22 .90

Auglaize River near Fort Jennings, Ohio 332 56,900 4,700 8.3

Cattaraugus Creek at Gowanda, N.Y. 436 nd nd nd

Black River near Jeddo, Mich. 464 22,900 1,200 5.1

Grand River at Harpersfield, Ohio 552 19,400 440 2.3

St. Joseph River near Newville, Ind. 610 73,900 8,400 10.6

Cuyahoga River at Cleveland, Ohio 788 17,800 260 1.5

Maumee River at New Haven, Ind. 1,967 309,000 22,000 7.1

Maumee River at Waterville, Ohio 6,330 1,070,000 47,000 4.4
40 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

In general, the frequency of detection of pesticides in samples collected from streams in the Lake

Erie Basin increased as the amount of pesticides

used in those stream basins increased (fig. 16A).

Pendimethalin is an exception; although more

than 300,000 lb of this herbicide were applied in

1995 in the Basin, it rarely was detected. Application data were available only for pesticides used

in agricultural areas; as a result, pesticides with

significant nonagricultural use (such as chlorpyrifos, diazinon, prometon, simazine, and tebuthiuron)

will be underestimated (Aspelin, 1997).

There was also a trend of increasing frequency

of detection with increasing runoff potential. Pesticides with medium or small runoff potential could

be detected at a higher frequency if greater amounts

of pesticide are applied—as reflected by detections

of cyanazine, alachlor, and acetochlor. Linuron

(large runoff potential) and pendimethalin (medium

runoff potential) plot much lower than other pesticides with large or medium runoff potential and are

exceptions to this trend.

Because families of pesticides have similar

chemical structure and physical properties,

similar frequency of detections would be expected

when families of pesticides are analyzed (fig. 16B).

In general, the families of pesticides detected more

than 10 percent of the time can be categorized in

decreasing order of detection frequency: triazines,

amides, organophosphates, ureas, carbamates,

organochlorines, and dinitroanalines. Linuron and

tebuthiuron, both members of the urea family, have

large runoff potential yet the lowest frequency

of detection of all of the compounds that have a

large runoff potential. This may be a factor of the

amount of pesticide applied, the timing of application, or method of application that hinders runoff.

Pendimethalin, the sixth most-applied pesticide

in the Basin, has a much lower frequency of detection than the other heavily used pesticides with

medium runoff potential (alachlor, acetochlor, and

cyanazine). This lower frequency is more likely

a function of pendimethalin having a lower water

solubility and higher Koc value than the other herbicides with higher frequencies of detection (Panshin

and others, 1998).

Pesticide Use

Pesticide concentrations in streams are related

to pesticide use, as illustrated by the application

and concentrations of atrazine (fig. 17, p. 42). The

maximum measured and median concentrations of

atrazine detected in streams tended to increase with

increasing application amounts. An exception to

this trend was observed at the Maumee River at

Waterville site, which is in the largest of the basins

sampled (6,330 mi2). Degradation of atrazine and

dilution by the larger volume of water may account

for this exception. Another exception was observed

at the Auglaize River site, where the maximum

(85 μg/L) and 95th percentile (40 μg/L) measured

concentrations were much higher than at the other

sites (table 4). These higher concentrations may

be explained by the very poorly drained soils in the

Auglaize River Basin, which necessitate tile drains

for agriculture. Even though the highest measured

concentrations were detected at the Auglaize River

near Fort Jennings, Ohio, site, median concentration of atrazine was highest at the Maumee River at

New Haven, Ind., site, probably because this basin

is six times larger than the Auglaize River Basin.

Changes in pesticide use over time can be seen

in the concentrations of alachlor and acetochlor

in the St. Joseph River (fig. 18, p. 43). Acetochlor

was conditionally registered for use by the USEPA

in 1994 (U.S. Environmental Protection Agency,

1994). Between 1991 and 1993, alachlor was

one of the most heavily used herbicides on corn

and soybeans in the Lake Erie Basin; nearly 10

to 12.5 million pounds were applied to corn and

soybeans in Ohio, Indiana, and Michigan. After

use of acetochlor began in 1994, use of alachlor

in the Basin dropped every year. Only about

800,000 pounds of alachlor were applied in these

states in 1997. Acetochlor usage increased from

1.1 million pounds in 1994 to about 5.4 million

pounds in 1996 and 1997. In 1996, the highest concentration of alachlor in a sample collected in

this study was greater than the highest measured

concentration of acetochlor; by 1997, the highest

measured acetochlor concentration was almost

double the highest concentration of alachlor, and it
Occurrence, Distribution, and Loads of Selected Pesticides 41

0 500 1,000 1,500 2,000 2,500

0

120

20

40

60

80

100

Amides

Carbamates

Dinitroanalines

Miscellaneous

Organochlorines

Organophosphates

Pyrethroids

Triazines

Uracils

Ureas

 PESTICIDE APPLICATION, IN 1,000 POUNDS OF ACTIVE INGREDIENT ON MAJOR CROPS

0

120

20

40

60

80

100

FREQUENCY OF DETECTION, IN PERCENT

Large runoff potential

Medium runoff potential

Small runoff potential

A

B

Figure 16. Relation of frequency of pesticide detection to pesticide application for all surface-water-sampling sites

by (A) runoff potential and (B) pesticide family, Lake Erie-Lake St. Clair Basin, 1996–98. (Pesticide-application data

Metolachlor Atrazine

Cyanazine

Alachlor

Acetochlor

Prometon

Simazine

Atrazine Metolachlor

Cyanazine

Acetochlor

Alachlor

Prometon

Simazine

Metribuzin

Metribuzin

Diazinon

Diazinon

Pendimethalin

Linuron Pendimethalin

Linuron

Tebuthiuron

Tebuthiuron

Chlorpyrifos

Chlorpyrifos

Only the most heavily applied pesticides or those with the most frequent detections were labeled.

from Brody and others, 1998.)

.
42 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

was nearly 10 times greater in 1998. Similar patterns for these herbicides were found in the White

River in Indiana (Crawford, 1997).

Environmental Factors

The amount and timing of rainfall after pesticide application affect pesticide concentrations

in surface water. A conceptual model of pesticide

interaction with soils and water shows these variations. After application, some of a pesticide is

taken up by the plants, some adsorbs to soils, some

volatilizes, and some goes into solution in the soil

water. In the soil, some of the pesticide breaks down

into degradates through biological or physical processes. When rain falls, some pesticides percolate

into soil until the soil becomes saturated. Once

the soil is saturated or the infiltration rate is exceeded, rainfall flows over the land surface as

runoff. More rain results in more runoff. Years with

long, intense rainfall on fields with relatively moist

soils shortly after pesticide application will result

in the transport of more pesticides into streams

than years in which the rain occurs a long time after

application. These differences in wet and dry years

and timing of rainfall can be seen in the concentrations of atrazine in the St. Joseph River from

1996 through 1998 (fig. 19, p. 44). In May and June

1996, streamflow was 330 to 340 percent of the normal May–June flow; in 1997, streamflow was 103

to 129 percent of the normal May–June flow; and

in 1998, streamflow was 36 to 78 percent of the

normal May–June flow. 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 19981.

1When the medians were calculated from the same

number of samples per month from March to December in

1996, 1997, and 1998, the medians were 0.47 μg/L, 0.30 μg/L,

and 0.13 μg/L, respectively.

River

Clinton

Raisin

River

River Cuyahoga River

Grand

River

Black

River

Auglaize

River

Joseph

St.

Haven

New

RiverMaumee

Waterville

RiverMaumee

0.002

200

0.005

0.01

0.02

0.05

0.1

0.2

0.5

1

2

5

10

20

50

100

ATRAZINE CONCENTRATION,

IN MICROGRAMS PER LITER

10th percentile

25th percentile

Median

75th percentile

90th percentile

 10th and 90th percentiles

Data values outside the

0

400

100

200

300

ATRAZINE APPLICATION,

IN THOUSAND POUNDS

PER YEAR

Primary Land Use

Urban

Row Crop

Mixed

Pasture/forest

Maximum use 1,071,000 pounds

Figure 17. Atrazine application in 1997 and concentrations, by site. Lake Erie-Lake St. Clair River Basin surfacewater-sampling sites listed in of order increasing application of atrazine. (Application data from National Agricultural

EXPLANATION

Statistics Service, 1999.)
90 91 92 93 94 95 96 97 98 99

0

6,000

2,000

4,000

PESTICIDE APPLICATION, IN THOUSAND

POUNDS OF ACTIVE INGREDIENT

ACETOCHLOR

ALACHLOR

0

6

1

2

3

4

5

0

10,000

2,000

4,000

6,000

8,000

STREAMFLOW

ALACHLOR

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

10,000

2,000

4,000

6,000

8,000

HERBICIDE CONCENTRATION, IN MICROGRAMS PER LITER

0

6

1

2

3

4

5

STREAMFLOW, IN CUBIC FEET PER SECOND

STREAMFLOW

ACETOCHLOR

ALACHLOR

ACETOCHLOR

Figure 18. Relation of alachlor and acetochlor concentrations and streamflow to time in the

St. Joseph River near Newville, Ind., and alachlor and acetochlor application in Indiana 1991–98.

(Application data from National Agricultural Statistics Service, 1999.)

Application in Indiana

0
44 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

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

CUBIC FEET PER SECOND

0

10,000

2,000

4,000

6,000

8,000

ATRAZINE CONCENTRATION, IN

MICROGRAMS PER LITER

STREAMFLOW

ATRAZINE

Figure 19. Relation of atrazine concentrations and streamflow to time in the St. Joseph River near

Newville, Ind., March 1996-September 1998.

The maximum measured atrazine concentration

detected in the stream was 16 μg/L in 1996, 23 μg/L

in 1997, and 4.7 μg/L in 1998. Differences in the

timing of rainfall between 1996 and 1998 also influenced when maximum measured concentrations of

pesticides occurred. Above-average rainfall led to

the highest recorded streamflow in May 1996 in

the St. Joseph River between 1947 and 1998 and

delayed planting. Peak concentrations of rainfall

occurred 2 to 4 weeks later in 1996 than in 1997.

Another factor that appears to influence pesticide concentrations in streams is soil permeability.

Well-drained soils (hydrologic soil type A and B

soils in the State Soil Geographic Data Base in

Wolock, 1997) allow water to percolate to ground

water. As water percolates through soil, some

pesticides are filtered by the soil and broken down

to degradates by bacteria. In areas with impermeable soils, more water enters streams as surface

runoff. Such areas also require tile drains to make

the land arable. Because tile drains lessen the

underground filtration of the soils, they can transport elevated concentrations of pesticides (Fenelon,

1998; Zucker and Brown, 1998). This may account

for the elevated pesticide concentrations in the

Auglaize River. In four row-crop basins in which

the percentage of permeable soils ranges from

2 percent (Auglaize River Basin) to 58 percent

(River Raisin Basin), comparisons of the percentage of atrazine exported in streams to the amount

applied in the basin illustrate the generally increasing amount of atrazine exported in basins with more

impermeable soils (fig. 20). This trend corresponds

to the more frequent detections and higher concentrations of pesticides and degradates in ground

water in areas with more permeable soils than in

areas with more impermeable soils (M.A. Thomas,

U.S. Geological Survey, oral commun., 2000).

Apparently, at least one factor is unaccounted for

because the St. Joseph and Black Rivers, which

have similar percentages of permeable soils (22 and

20 percent, respectively) have different amounts of

pesticide detected. One factor that could account

for this difference is streamflow. Higher streamflow, especially in the spring, could influence the

amount of pesticide in the stream. It appears, however, that the 30-year normals for precipitation

and streamflow were similar for the St. Joseph and

Black Rivers (fig. 3).
Summary and Conclusions 45

Summary and Conclusions

As part of the U.S. Geological Survey’s

National Water-Quality Assessment (NAWQA)

Program, 315 pesticide samples were collected

from 10 streams in the Lake Erie-Lake St. Clair

Basin. Two agricultural herbicides, metolachlor

and atrazine, are the most heavily used pesticides in the Basin. In 1995, approximately 2.0

and 1.7 million pounds of metolachlor and atrazine,

respectively, were applied in the Basin. Herbicides

are used much more heavily than insecticides in

agricultural areas. Seven of the 10 most heavily

applied agricultural pesticides were herbicides

used primarily on corn and soybeans and include

metolachlor, atrazine, cyanazine, acetochlor,

alachlor, pendimethalin, and metribuzin. Although

data on urban pesticide use are lacking, insecticides

usually account for a larger percentage of the overall use in urban areas than in agricultural areas

planted in corn and soybeans.

Of the 44 pesticides and three degradates

evaluated in this study, 30 were detected at least

once. Atrazine was detected in every sample. Deethylatrazine, metolachlor, and simazine were

detected in more than 90 percent of the samples.

Eight pesticides had a frequency of detection

greater than 50 percent. The pesticides that were

the most heavily applied in the Basin were generally those most frequently detected in streams in

the Basin. Herbicides, therefore, were detected

more frequently than insecticides. Diazinon and

chlorpyrifos were the most frequently detected

insecticides. In general, the number of detections

increased with basin size. In the River Raisin near

Manchester, Mich., (the smallest basin sampled at

132 mi2) 14 pesticides were detected at least once;

27 pesticides were detected at the Maumee River

at Waterville, Ohio (the largest basin at 6,330 mi2

).

Atrazine and metolachlor were detected at

the highest concentrations (85 and 78 μg/L, respectively). Pesticide concentrations in streams showed

pronounced seasonal trends. Row-crop herbicides

applied in the spring, such as atrazine, had elevated

concentrations in the spring; pesticides usually

applied in the late summer or early fall, such as

diazinon, had maximum measured concentrations

at those times. Maximum measured concentrations

in streams occurred after application and corresponded with rainfalls that carried the pesticides

into the streams. The amount of pesticides detected in streams also was influenced by hydrologic

conditions. Differences in the timing and amount

of rainfall between 1996 and 1998 influenced the

concentrations of pesticides detected. AboveRiver Raisin Black River

River St. Joseph Auglaize River 0

15

5

10

PERCENTAGE OF APPLIED ATRAZINE

EXPORTED TO STREAMS

58

Figure 20. Percentage of applied atrazine exported to streams in row-crop basins and

the percentage of permeable soils in each study basin of the Lake Erie-Lake St. Clair

20

22

2

58 Percentage of permeable soils

Basin, 1996–98.
46 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

average rainfall in May and June 1996 delayed

planting, and maximum measured concentrations

of pesticides were detected 2 to 4 weeks later

in 1996 than in 1997. Maximum measured and

median concentrations were higher in 1996

and 1997 than in 1998 because of the aboveaverage rainfall and streamflow in 1996 and 1997

(compared to the below-average rainfall and

streamflow in 1998).

The highest pesticide loads were of atrazine

and metolachlor at the Maumee River at Waterville, Ohio, with 47,000 and 44,000 pounds in

1997, respectively. Two basins in which row-crop

agriculture dominated—the St. Joseph River near

Newville, Ind., and the Auglaize River near Fort

Jennings, Ohio—had the highest yields of the

herbicides acetochlor, alachlor, atrazine, cyanazine, metolachlor, and simazine. The St. Joseph

and Auglaize Rivers had the highest yields of

commonly used row-crop herbicides, with atrazine

yields of 14 lb/mi2/yr for both of these streams.

Metolachlor yields were 12 and 16 lb/mi2

/yr,

respectively. The Cuyahoga River at Cleveland,

Ohio, had the highest yields of diazinon and prometon—pesticides typically applied more heavily

in urban areas. Pesticide loads in streams as a percentage of the amount applied to cropland in the

basin ranged from 3 to 7 percent at the Maumee

River at Waterville, Ohio; these percentages tended

to be highest in the smaller basins.

All of the herbicide degradates analyzed for

were detected in at least 6 of 10 of the samples.

Alachlor ESA, metolachlor ESA, and metolachlor

oxanilic acid were detected in 100 percent (10

of 10 samples). Acetochlor oxanilic acid had the

highest detected concentration (6.76 μg/L). Seasonal variation was similar for the degradates to

that of the parent compounds. Acetanilide degradates constituted a much larger fraction of the

amount of acetanilide herbicides washing off the

fields than triazine degradates did for triazine

herbicides. These data, though limited, suggest

that degradates—especially acetanilides—can

contribute a significant load into Lake Erie.

The annual time-weighted average concentrations did not exceed the primary drinking-water

standards or health advisories at any of the surfacewater-sampling sites. During May through July,

however, when most pesticides run off into streams,

time-weighted average concentrations for this time

period exceeded the MCL for atrazine at five rowcrop sites. There were no exceedences of the acute,

longer-term, or lifetime health advisories. Timeweighted average concentrations of atrazine and

cyanazine frequently exceeded HA-L guidelines

during May through July. For some heavily used

herbicides such as atrazine, metolachlor, cyanazine,

and acetochlor, elevated concentrations were detected for 4 to 6 weeks after the initial maximum

measured concentration in the row-crop basins.

Acetochlor was twice detected at levels above

8.00 μg/L in two streams used as a drinking-water

supply, which triggers additional sampling as part

of the conditional registration for acetochlor.

The percentage of atrazine that was applied and

then detected in streams generally increased when

the amount of permeable soils decreased within

each basin. More permeable soils allow water to

percolate into ground water and require less use of

tile drains. A lower percentage of atrazine was

found in the River Raisin, which has 58 percent

permeable soils, compared to the Black River,

St. Joseph River, and Auglaize River, which have

20, 22, and 2 percent permeable soils.

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Appendix A

Quality Assurance: Field Blanks, Field Spikes, and Split Replicates

Tables A1–A2

Figure A1
52 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Quality Assurance

Data from field blanks, field and laboratory

spikes, and split replicates were used to estimate

bias and variability in the measurement of pesticides. A field blank is a pesticide-free water sample

that is processed through the sampling equipment

and sent to the laboratory for analysis, following

the same procedures as those used for environmental samples. Analysis of field blanks provides an

estimate to determine whether the equipment,

field technicians, transportation of the samples,

site atmosphere, laboratory analysis, or other

sources could have contaminated the environmental samples.

A spike is a sample of streamwater or

pesticide-free water used to estimate positive or

negative bias in environmental samples caused

by matrix interference or pesticide degradation.

Matrix interference can cause a positive or negative

bias (over- or underestimation of the true amount of

pesticides in the sample), and pesticide degradation

can cause a negative bias. Matrix interference

occurs when compounds in the water prevent accurate measurement of pesticides, using current

analytical methods (Mueller and others, 1997).

Pesticide degradation occurs when the parent compound breaks down into a metabolite before the

sample is analyzed. A spike is a streamwater or

pesticide-free water sample that has had a known

amount of pesticides added. For each spike, an

unspiked streamwater sample (the environmental

sample) is collected at the same time to estimate

the background concentration (the concentration of

pesticides in the spike before the pesticides were

added). The percent recovery of each pesticide in

the spike is calculated by subtracting the concentration of the pesticide in the spiked sample from the

concentration in the environmental sample and

dividing by the expected concentration in the spike.

The expected concentration is the concentration

that would be found if there were 100-percent

recovery of the spike compounds added to the

sample.

A split replicate is a second environmental

sample used to estimate variability. A split replicate is obtained by splitting a large volume of

streamwater into two samples (one is considered

to be the environmental sample and the other is

the split replicate). Because the environmental

and split-replicate samples come from the same

volume of streamwater, analytical differences between the two samples should reflect the variability

associated with either the field or laboratory processes.

Field Blanks

Contamination associated with the pesticide

data was estimated, using seven field blanks

collected at three surface-water-sampling sites

between December 1996 and June 1997. Fieldblank samples were collected prior to collecting

the environmental samples. Seven pesticides were

detected at least once in the field-blank samples

(table A1). Of the pesticides with detections, only

metolachlor—with six detections—was detected

in more than two of the seven field blanks. The

median of these detections was 0.004 μg/L, and

the maximum was 0.007 μg/L. Even though metolachlor frequently was detected in the field blanks,

the concentrations were very low compared to

environmental samples. Metolachlor was detected

(the method detection limit is 0.002 μg/L) in

99.3 percent of the 305 environmental samples. The

frequency of detection would decrease to 96.7 percent if metolachlor were censored at 0.003 μg/L. If

censored at 0.007 μg/L, the frequency of detection

of metolachlor in the environmental samples would

decrease to 84.9 percent.

Diazinon was detected in one sample blank

at the highest concentration (0.179 μg/L) of all

458 surface-water blanks collected by all NAWQA

1991 and 1994 Study Units (Jeffrey D. Martin,

U.S. Geological Survey, written commun., 2000).

The reported value was verified by the NWQL;

however, the validity of the sample is questionable

because there were no detections in the environmental samples at the previous site or at the site

where the blank was collected. Also, the blank

does not appear to be a sample switched with an

environmental sample because commonly detected

pesticides such as atrazine and metolachlor were

not detected in the blank.
Bias and Variability Estimates 53

Table A1. Bias and variability estimates for 7 field blanks and 10 split-replicate samples, Lake Erie-Lake St. Clair Basin, 1996–98[(μg/L), microgram per liter; E, estimated; nd, not detected]

Field blanks Split replicates

Pesticide

Method

detection

limit

(μg/L)

Number

of

detections

Median

concentration

detected

(μg/L)

Maximum

concentration

detected

(μg/L)

Number

of

detections

Minimum

concentration

detected

(μg/L)

Maximum

concentration

detected

(μg/L)

Me

per

diffe

f

dete

pest

Acetochlor 0.002 0 nd nd 8 0.010 0.518 3Alachlor .002 0 nd nd 10 .005 .222 5Atrazine .001 2 .009 .015 10 .033 6.98 3Atrazine, deethyl .002 0 nd nd 10 E .006 E .557 13Azinphos, methyl .001 0 nd nd 0 nd nd nBenfluralin .002 0 nd nd 0 nd nd nButylate .002 0 nd nd 0 nd nd nCarbaryl .003 0 nd nd 2 E .003 E .015 87Carbofuran .003 0 nd nd 1 E .003 E .007 77Chlorpyrifos .004 2 .0175 .019 3 .004 .021 75Cyanazine .004 0 nd nd 10 .010 1.52 4DCPA .002 2 E .002 E .002 5 E .0005 .006 51DDE, p,p’ .006 1 E .002 E .002 0 nd nd n

Diazinon .002 2 .119 .179 5 .002 .007 18Dieldrin .001 0 nd nd 0 nd nd nDiethylanaline-2,6 .003 0 nd nd 0 nd nd nDisulfoton .017 0 nd nd 0 nd nd nEPTC .002 0 nd nd 1 .003 .003 18Ethalfluralin .004 0 nd nd 0 nd nd nEthoprop .003 0 nd nd 0 nd nd nFonofos .003 0 nd nd 0 nd nd nalpha-HCH .002 0 nd nd 0 nd nd ngamma-HCH .004 0 nd nd 0 nd nd nLinuron .002 0 nd nd 4 .004 .016 14
Table A1. Bias and variability estimates from 7 field blanks and 10 split-replicate samples, Lake Erie-Lake St. Clair Basin, 1996

–9

54 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98 Malathion 0.005 1 0.022 0.022 0 nd nd n

Methyl parathion .006 0 nd nd 0 nd nd nMetolachlor .002 6 .0035 .007 10 .036 4.62 4Metribuzin .004 0 nd nd 9 .004 .207 9Molinate .004 0 nd nd 1 .004 .004 13Napropamide .003 0 nd nd 0 nd nd nParathion .004 0 nd nd 0 nd nd nPebulate .004 0 nd nd 0 nd nd nPendimethalin .004 0 nd nd 0 nd nd nPermethrin, cis .005 0 nd nd 0 nd nd nPhorate .002 0 nd nd 0 nd nd nPrometon .003 0 nd nd 10 .003 .046 9Pronamide .003 0 nd nd 0 nd nd nPropachlor .007 0 nd nd 0 nd nd nPropanil .004 0 nd nd 0 nd nd nPropargite .013 0 nd nd 0 nd nd nSimazine .005 0 nd nd 10 .004 .682 5Tebuthiuron .010 0 nd nd 6 .006 .024 24Terbacil .007 0 nd nd 0 nd nd nTerbufos .013 0 nd nd 0 nd nd nThiobencarb .002 0 nd nd 0 nd nd nTriallate .001 0 nd nd 0 nd nd nTrifluralin .002 0 nd nd 1 .003 .004 5

Field blanks Split replicates

Pesticide

Method

detection

limit

(μg/L)

Number

of

detections

Median

concentration

detected

(μg/L)

Maximum

concentration

detected

(μg/L)

Number

of

detections

Minimum

concentration

detected

(μg/L)

Maximum

concentration

detected

(μg/L)

Me

per

diffe

f

dete

pest
Field Spikes 55

The frequency of detection of p,p’-DDE

(14.3 percent) was higher in the seven blanks

collected than in the 302 environmental samples

(1.3 percent) in the Lake Erie study. This makes

the p,p’-DDE data questionable. All four detections

of p,p’-DDE in environmental samples, however,

were found in Michigan and the single detection

of p,p’-DDE was found in a blank collected at the

St. Joseph River near Newville, Ind. Furthermore,

although p,p’-DDE was detected in 14.3 percent of

the blanks (1 of 7 blanks) collected in the Lake Erie

study, of the 458 blanks collected by all NAWQA

Study Units only 2.8 percent had detections (Jeffrey

D. Martin, U.S. Geological Survey, written commun., 2000).

Field Spikes

Three sets of field spikes were collected at

different concentrations to determine the accuracy

with which the National Water Quality Laboratory

can measure a known amount of pesticide over a

range of concentrations. Fifteen spiked samples

were collected. To evaluate recovery at low concentrations, duplicate field spikes (six total samples)

at concentrations of 0.1 μg/L were sampled for all

47 pesticides at the St. Joseph River near Newville,

Ind., and the Auglaize River near Fort Jennings,

Ohio, in December 1996 and at the Black River

near Jeddo, Mich., in April 1997. To evaluate recovery at medium concentrations, single field spikes

(three total samples) with concentrations of 0.1,

3.0, and 6.0 μg/L, respectively, for 16 heavily used

row-crop pesticides were sampled at the St. Joseph

River near Newville, Ind., in July 1998. To evaluate

recovery at high concentrations, duplicate field

spikes (six total samples) with concentrations of

2.0 to 20.0 μg/L were sampled for the same 16

row-crop pesticides at the St. Joseph River near

Newville, Ind.; Auglaize River near Fort Jennings,

Ohio; and the Maumee River at Waterville, Ohio,

in April 1997.

The 15 spiked samples were analyzed, using

the gas chromatography/mass spectroscopy

(GC/MS) method. Twenty-six of the pesticides

had median recovery within 10 percent of 100 percent. For 40 of the 47 pesticides and degradates

analyzed in the spikes, using the GC/MS method,

the median percent recovery ranged from 71 to

130 percent (table A2). Of the seven compounds

outside this range, four were biased low: deethylatrazine (50 percent), disulfoton (56 percent),

phorate (57 percent), and p,p’-DDE (66 percent).

Three were biased high: carbaryl (254 percent),

carbofuran (172 percent), and tebuthiuron (136 percent).

Twelve of the 16 pesticides spiked at 0.1,

3.0, and 6.0 μg/L in 1998 had similar recoveries

as the 0.1-μg/L field spikes obtained in 1996

and 1997, indicating that bias is not a function of

concentration. Recoveries of the four remaining

pesticides were a function of concentration; deethylatrazine, cyanazine, carbofuran, and carbaryl

showed statistically significant decreases in recovery at higher concentrations (Jeffrey D. Martin,

U.S. Geological Survey, oral commun., 1999),

indicating that they are underestimated at higher

concentrations.

Because replicates were collected for 12 of

the 15 spikes, variability can be calculated. The

Relative Interquartile Range (RIQR) is a nonparametric measurement of variability around

the median. The RIQR is calculated as:

[(75% Quartile - 25% Quartile)/Median) x 100].

The RIQR ranged from 3 for ethoprop to 130 for

disulfoton. The median IQR for all pesticides

was 20 percent. Ten pesticides had variability

with a RIQR greater than 40 percent, including

metribuzin (48 percent), propargite (51 percent),

tebuthiuron (52 percent), terbacil (52 percent),

cis-permethrin (58 percent), terbufos (61 percent),

linuron (62 percent), deethylatrazine (84 percent),

phorate (123 percent), and disulfoton (130 percent).

A comparison of spikes analyzed by the

NQWL for internal quality assurance with

the seven field spikes at the same concentrations

indicates that the measurement of some compounds

may be affected by matrix interference (table A2).

Between March 1996 and February 1998, 751

to 754 spikes were analyzed using pesticide-free

water at the NWQL. Twenty-eight of the 47 pesticides had median recoveries of 10 percent or less

(90–110 percent recovery). The difference between

median recoveries in laboratory and field spikes
56 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98 Table A2. Precision and bias estimates for pesticides in 7 field spikes from the Lake Erie-Lake St. Clair Basin, March 1996

–Febru

laboratory spikes for all National Water-Quality Assessment Program Study Units

[IQR, interquartile range]

Compound

Median

recovery

—

field

(percent)

Relative

IQR

—

field

Median

recovery

—

laboratory

(percent)

Relative

IQR

—

laboratory Pesticide

Median

recovery

—

field

(percent)

Relativ

IQR

—

field

Acetochlor 98 7 97 12 Linuron 102 62 Alachlor 101 20 103 11 Malathion 107 16 Atrazine 87 17 100 11 Methyl parathion 126 18 Atrazine, deethyl 50 84 44 42 Metolachlor 92 23 Azinphos, methyl 118 21 81 70 Metribuzin 109 48 Benfluralin 107 7 68 32 Molinate 98 16 Butylate 105 8 89 11 Napropamide 99 11 Carbaryl 254 10 126 58 Parathion 130 14 Carbofuran 172 30 112 33 Pebulate 95 21 Chlorpyrifos 98 5 90 14 Pendimethalin 126 10 Cyanazine 108 39 103 24 Permethrin, cis 80 58 DCPA 96 5 104 12 Phorate 57 123 DDE, p,p’ 66 11 59 23 Prometon 102 27 

Diazinon 100 14 84 13 Pronamide 105 24 Dieldrin 93 20 82 19 Propachlor 124 12 Diethylanaline-2,6 83 25 85 11 Propanil 103 8 Disulfoton 56 130 73 32 Propargite 99 51 EPTC 94 28 91 9 Simazine 91 23 Ethalfluralin 120 12 78 30 Tebuthiuron 136 52 Ethoprop 93 3 96 17 Terbacil 101 52 Fonofos 89 27 88 14 Terbufos 71 61 alpha-HCH 88 8 90 14 Thiobencarb 97 5 gamma-HCH 97 6 92 16 Triallate 89 13 

Trifluralin 111 32 
Split Replicates 57

was 30 percent or greater for 12 pesticides; in these

samples, the laboratory spike values were always

less than in the field spikes. These large differences

between the field and laboratory spikes for certain

pesticides may be explained by (1) matrix interference or (2) improved recovery of spikes using

natural waters that have more ions compared to

those using pesticide-free water (pesticide recovery

is more effective with more ions, using the GC/MS

method) (Jeffrey D. Martin, U.S. Geological Survey, oral commun., 1999).

The variability (median RIQR) was approximately the same for the laboratory (19 percent)

and field spikes (20 percent). The range, however,

was smaller for the laboratory spikes than for the

seven field spikes. The RIQR for the laboratory

spikes ranged from 9 for ethoprop to 70 for disulfoton, with a median of 20 percent. A smaller RIQR

is expected because of the large number of samples

(more than 750). Eight pesticides had high variability (RIQR greater than 30 percent) in field or

laboratory spikes. Five pesticides (deethylatrazine,

disulfoton, linuron, phorate, and terbufos) had

much greater variability associated with the field

spikes (greater than 30 percent difference between

the field and laboratory RIQRs); three pesticides

(methyl azinphos, carbaryl, and prometon) had

much greater variability associated with the laboratory spikes.

Split Replicates

The precision of the pesticide data was estimated, using 10 split-replicate samples collected at

four surface-water-sampling sites between December 1996 and June 1997. Of the 47 compounds that

were analyzed, 19 were detected at least once;

therefore relative differences in concentrations

could be calculated (table A1). For replicates

with one detection and one nondetection, the MDL

concentration was used. The percent difference

between replicates was calculated as:

[EC - RC/(EC+RC)/2] x 100,

where,

EC is the concentration of the environmental sample and

RC is the concentration of the

split-replicate.

 The median percent differences for these

19 pesticides ranged from 3.3 (atrazine) to

87.4 percent (carbaryl). Compounds having the

most variability were carbaryl, carbofuran, chlorpyrifos, and DCPA—all of which had median percent

differences greater than 50 percent or more. Some

of the variability associated with these pesticides

results from detections near the MDL, where percent differences are greatest (Mueller and others,

1997). Only eight compounds were detected at

concentrations above 1 μg/L. As concentrations

approached the MDL, the variability increased

(fig. A1). Of the remaining 15 pesticides that were

detected, 4 had individual replicates that had maximum percent differences greater than 50 percent.

Two (carbofuran and prometon) had maximum percent differences between 75.0 and 99.9 percent, and

two (metribuzin and tebuthiuron) had maximum

percent differences between 50.0 and 74.9 percent.

In these four samples, carbofuran and metribuzin

were detected near the MDL. Three pesticides

(carbofuran, EPTC, and molinate) were detected

only once.

The results of the quality-assurance blank

samples indicate that, for most pesticides, bias

was low. Metolachlor was an exception. Because

the contamination of metolachlor was at low levels,

the analysis was unaffected and the data were

uncensored. The results of the field and laboratory

spikes indicate that the recovery of pesticides, using

GC/MS analysis, was effective for most of the

compounds analyzed; 28 of the 47 had recoveries

between 90 and 110 percent. Some pesticides consistently were biased low in recovery, and reported

concentrations were probably low, including those

for deethylatrazine, p,p’-DDE, disulfoton, and

phorate. Some pesticides were consistently biased

high in recovery, and reported concentrations were

probably high, including carbaryl, carbofuran, and

tebuthiuron. The results of the split-replicate samples indicate that intra-sample variability is low for

those pesticides most frequently detected. The variability was greater for some pesticides (carbaryl,

carbofuran, and chlorpyrifos) because of the low

number of detections in the split-replicate samples.

These results indicate that the reproducibility, and

thus the quality of the samples, was good.
0 1 2 3 4 5 6 7 8

ENVIRONMENTAL SAMPLE CONCENTRATION, IN MICROGRAMS PER LITER

0

8

2

4

6

REPLICATE SAMPLE CONCENTRATION, IN MICROGRAMS PER LITER

00 0.01 0.02 0.03 0.04 0.05 0

0.05

0

0.01

0.02

0.03

0.04

Figure A1. Percent differences and differences in concentration between the 10 environmental and

split-replicate samples for the Lake Erie-Lake St. Clair study, 1996–98.

Includes comparisons of all compounds with at least one detection.

Only the samples in the range of 0 to 0.05 ug/L are plotted.

1:1

Line

1:1

Line

00 1 2 3 4 5 6 7 8

AVERAGE OF ENVIRONMENTAL AND REPLICATE SAMPLES, IN MICROGRAMS PER LITER

-80.0

80.0

-60.0

-40.0

-20.0

0

20.0

40.0

60.0

AND REPLICATE SAMPLES (PERCENT)

Includes comparisons of all compounds with at least one detection.

DIFFERENCE BETWEEN THE ENVIRONMENTAL
Appendix B

Compounds Analyzed; Method Detection Limit; Number of Analyses; Frequency of Detection;

and the Median, 95th Percentile, and Maximum Concentration for Each Pesticide for Each Basin

Tables B1–B10
60 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Table B1. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the River Raisin near Manchester, Mich.

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 27 29.6 ld 0.042 0.045

Alachlor .002 27 25.9 ld .017 .040

Atrazine .001 27 100 .022 .248 .280

Atrazine, deethyl .002 27 100 E .008 E .036 E .045

Azinphos, methyl .001 27 0 -- -- --

Benfluralin .002 27 0 -- -- --

Butylate .002 27 0 -- -- --

Carbaryl .003 27 0 -- -- --

Carbofuran .003 27 0 -- -- --

Chlorpyrifos .004 27 0 -- -- --

Cyanazine .004 27 66.7 .008 .030 .152

DCPA .002 26 3.7 ld ld E .001

DDE, p,p’ .006 27 3.7 ld ld E .002

Diazinon .002 27 37.0 ld .008 .009

Dieldrin .001 27 0 -- -- --

Diethylanaline-2,6 .003 27 0 -- -- --

Disulfoton .017 27 0 -- -- --

EPTC .002 27 0 -- -- --

Ethalfluralin .004 27 0 -- -- --

Ethoprop .003 27 0 -- -- --

Fonofos .003 27 3.7 ld ld E .003

HCH, alpha .002 27 0 -- -- --

HCH, gamma .004 27 0 -- -- --

Linuron .002 27 0 -- -- --

Malathion .005 27 0 -- -- --

Metolachlor .002 27 92.6 .007 .038 .067

Metribuzin .004 27 11.1 ld .023 .024

Molinate .004 27 0 -- -- --

Napropamide .003 27 0 -- -- --

Parathion .004 27 0 -- -- --

Parathion, methyl .006 27 0 -- -- --

Pebulate .004 27 0 -- -- --

Pendimethalin .004 27 0 -- -- --

Permethrin, cis .005 27 0 -- -- --

Phorate .002 27 0 -- -- --

Prometon .003 27 44.4 ld .017 .018

Pronamide .003 27 0 -- -- --

Propachlor .007 27 0 -- -- --

Propanil .004 27 0 -- -- --

Propargite .013 27 0 -- -- --

Simazine .005 27 100 .042 1.09 1.63

Tebuthiuron .010 27 7.4 ld E .002 E .004

Terbacil .007 27 0 -- -- --

Terbufos .013 27 0 -- -- --

Thiobencarb .002 27 0 -- -- --

Triallate .001 27 0 -- -- --

Trifluralin .002 27 0 -- -- --
Compounds Analyzed 61

Table B2. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the Clinton River at Sterling Heights, Mich.

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 37 29.7 ld 0.022 0.320

Alachlor .002 37 29.7 ld .019 .087

Atrazine .001 37 100 .026 .117 .410

Atrazine, deethyl .002 37 97.3 E .008 E .018 E .022

Azinphos, methyl .001 37 0 -- -- --

Benfluralin .002 37 5.4 ld E .003 E .004

Butylate .002 37 0 -- -- --

Carbaryl .003 37 35.1 ld E .102 E .139

Carbofuran .003 37 0 -- -- --

Chlorpyrifos .004 37 18.9 ld .011 .011

Cyanazine .004 37 29.7 ld .014 .022

DCPA .002 37 18.9 ld .003 .005

DDE, p,p’ .006 37 0 -- -- --

Diazinon .002 37 67.6 .012 .152 .197

Dieldrin .001 37 0 -- -- --

Diethylanaline-2,6 .003 37 0 -- -- --

Disulfoton .017 37 0 -- -- --

EPTC .002 37 0 -- -- --

Ethalfluralin .004 37 0 -- -- --

Ethoprop .003 37 0 -- -- --

Fonofos .003 37 0 -- -- --

HCH, alpha .002 37 0 -- -- --

HCH, gamma .004 37 0 -- -- --

Linuron .002 37 0 -- -- --

Malathion .005 37 5.4 ld .010 .026

Metolachlor .002 37 100 .010 .078 .260

Metribuzin .004 37 13.5 ld .024 .035

Molinate .004 37 0 -- -- --

Napropamide .003 37 0 -- -- --

Parathion .004 37 0 -- -- --

Parathion, methyl .006 37 0 -- -- --

Pebulate .004 37 0 -- -- --

Pendimethalin .004 37 16.2 ld .015 .144

Permethrin, cis .005 37 0 -- -- --

Phorate .002 37 0 -- -- --

Prometon .003 37 94.5 .015 .139 .228

Pronamide .003 37 0 -- -- --

Propachlor .007 37 0 -- -- --

Propanil .004 37 0 -- -- --

Propargite .013 37 0 -- -- --

Simazine .005 37 97.3 .014 .049 .070

Tebuthiuron .010 37 8.1 ld E .005 E .006

Terbacil .007 37 0 -- -- --

Terbufos .013 37 0 -- -- --

Thiobencarb .002 37 0 -- -- --

Triallate .001 37 0 -- -- --

Trifluralin .002 37 16.2 ld .004 .006
62 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Table B3. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the Auglaize River near Fort Jennings, Ohio

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 36 86.1 0.017 5.06 5.13

Alachlor .002 36 97.2 .022 3.32 4.59

Atrazine .001 36 100 .379 E 40 E85

Atrazine, deethyl .002 36 100 E .063 E 1.05 E 1.51

Azinphos, methyl .001 35 0 -- -- --

Benfluralin .002 36 0 -- -- --

Butylate .002 36 0 -- -- --

Carbaryl .003 36 11.1 ld E .024 E .432

Carbofuran .003 36 8.3 ld E .007 E .007

Chlorpyrifos .004 35 22.2 ld .024 .051

Cyanazine .004 36 97.2 .095 6.98 7.00

DCPA .002 35 8.3 ld E .001 E .002

DDE, p,p’ .006 36 0 -- -- --

Diazinon .002 36 44.4 ld .037 .048

Dieldrin .001 36 2.8 ld ld .004

Diethylanaline-2,6 .003 36 0 -- -- --

Disulfoton .017 36 0 -- -- --

EPTC .002 36 0 -- -- --

Ethalfluralin .004 36 0 -- -- --

Ethoprop .003 36 0 -- -- --

Fonofos .003 36 0 -- -- --

HCH, alpha .002 36 0 -- -- --

HCH, gamma .004 36 0 -- -- --

Linuron .002 36 2.8 ld ld .023

Malathion .005 36 2.8 ld ld .019

Metolachlor .002 36 100 .529 E37 E78

Metribuzin .004 36 88.9 .033 3.31 5.36

Molinate .004 36 0 -- -- --

Napropamide .003 36 0 -- -- --

Parathion .004 36 0 -- -- --

Parathion, methyl .006 36 0 -- -- --

Pebulate .004 36 0 -- -- --

Pendimethalin .004 36 8.3 ld .045 E .113

Permethrin, cis .005 36 0 -- -- --

Phorate .002 36 0 -- -- --

Prometon .003 36 94.4 .027 .149 .174

Pronamide .003 36 0 -- -- --

Propachlor .007 36 0 -- -- --

Propanil .004 36 0 -- -- --

Propargite .013 36 0 -- -- --

Simazine .005 36 97.2 .052 2.57 3.05

Tebuthiuron .010 36 22.2 ld .013 .013

Terbacil .007 36 0 -- -- --

Terbufos .013 36 0 -- -- --

Thiobencarb .002 36 0 -- -- --

Triallate .001 36 0 -- -- --

Trifluralin .002 36 11.1 ld .004 .009
Compounds Analyzed 63

Table B4. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the Cattaraugus Creek at Gowanda, N.Y.

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 24 4.2 ld ld 0.005

Alachlor .002 24 16.7 ld .015 .018

Atrazine .001 24 100 .011 .306 .347

Atrazine, deethyl .002 24 100 E .006 E .022 E .023

Azinphos, methyl .001 24 0 -- -- --

Benfluralin .002 24 0 -- -- --

Butylate .002 24 0 -- -- --

Carbaryl .003 24 4.2 ld ld E .011

Carbofuran .003 24 0 -- -- --

Chlorpyrifos .004 24 0 -- -- --

Cyanazine .004 24 8.3 ld .006 .023

DCPA .002 24 0 -- -- --

DDE, p,p’ .006 24 0 -- -- --

Diazinon .002 24 0 -- -- --

Dieldrin .001 24 0 -- -- --

Diethylanaline-2,6 .003 24 0 -- -- --

Disulfoton .017 24 0 -- -- --

EPTC .002 24 4.2 ld ld E .002

Ethalfluralin .004 24 0 -- -- --

Ethoprop .003 24 0 -- -- --

Fonofos .003 24 0 -- -- --

HCH, alpha .002 24 0 -- -- --

HCH, gamma .004 24 0 -- -- --

Linuron .002 24 0 -- -- --

Malathion .005 24 0 -- -- --

Metolachlor .002 24 100 .004 .304 .367

Metribuzin .004 24 0 -- -- --

Molinate .004 24 0 -- -- --

Napropamide .003 24 0 -- -- --

Parathion .004 24 0 -- -- --

Parathion, methyl .006 24 0 -- -- --

Pebulate .004 24 0 -- -- --

Pendimethalin .004 24 0 -- -- --

Permethrin, cis .005 24 0 -- -- --

Phorate .002 24 0 -- -- --

Prometon .003 24 12.5 ld E .003 E .003

Pronamide .003 24 0 -- -- --

Propachlor .007 24 0 -- -- --

Propanil .004 24 0 -- -- --

Propargite .013 24 0 -- -- --

Simazine .005 24 79.2 .003 .011 .227

Tebuthiuron .010 24 0 -- -- --

Terbacil .007 24 0 -- -- --

Terbufos .013 24 0 -- -- --

Thiobencarb .002 24 0 -- -- --

Triallate .001 24 0 -- -- --

Trifluralin .002 24 0 -- -- --
64 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Table B5. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the Black River near Jeddo, Mich.

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 28 75.0 0.018 1.49 E 3.80

Alachlor .002 28 96.4 .027 1.03 1.32

Atrazine .001 28 100 .237 7.21 7.32

Atrazine, deethyl .002 28 100 E .037 E .542 E .622

Azinphos, methyl .001 28 0 -- -- --

Benfluralin .002 28 0 -- -- --

Butylate .002 28 7.1 ld .011 .021

Carbaryl .003 28 7.1 ld E .013 E .019

Carbofuran .003 28 3.6 ld ld E .006

Chlorpyrifos .004 28 7.1 ld .005 .018

Cyanazine .004 28 100 .060 2.76 3.39

DCPA .002 27 10.7 ld E .002 E .003

DDE, p,p’ .006 28 10.7 ld E .002 E .003

Diazinon .002 28 7.1 ld .010 .028

Dieldrin .001 28 0 -- -- --

Diethylanaline-2,6 .003 28 0 -- -- --

Disulfoton .017 28 0 -- -- --

EPTC .002 28 53.6 .001 .176 .177

Ethalfluralin .004 28 0 -- -- --

Ethoprop .003 28 0 -- -- --

Fonofos .003 28 7.1 ld .008 .021

HCH, alpha .002 28 0 -- -- --

HCH, gamma .004 28 0 -- -- --

Linuron .002 28 28.6 ld .068 .090

Malathion .005 28 0 -- -- --

Metolachlor .002 28 100 .451 E25.9 E 37

Metribuzin .004 28 82.1 .021 .640 .866

Molinate .004 28 0 -- -- --

Napropamide .003 28 0 -- -- --

Parathion .004 28 0 -- -- --

Parathion, methyl .006 28 0 -- -- --

Pebulate .004 28 0 -- -- --

Pendimethalin .004 28 17.9 ld .056 .071

Permethrin, cis .005 28 0 -- -- --

Phorate .002 28 0 -- -- --

Prometon .003 28 64.3 .006 .025 .032

Pronamide .003 28 0 -- -- --

Propachlor .007 28 0 -- -- --

Propanil .004 28 0 -- -- --

Propargite .013 28 0 -- -- --

Simazine .005 28 96.4 .009 .104 .140

Tebuthiuron .010 28 10.7 ld E .004 E .005

Terbacil .007 28 14.3 ld E .013 E .021

Terbufos .013 28 0 -- -- --

Thiobencarb .002 28 0 -- -- --

Triallate .001 28 0 -- -- --

Trifluralin .002 28 25.0 ld .005 .006
Compounds Analyzed 65

Table B6. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the Grand River at Harpersfield, Ohio

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 28 57.1 0.007 0.165 0.410

Alachlor .002 28 35.7 ld .075 .138

Atrazine .001 28 100 .185 2.45 2.57

Atrazine, deethyl .002 28 100 E .029 E .200 E .211

Azinphos, methyl .001 28 0 -- -- --

Benfluralin .002 28 0 -- -- --

Butylate .002 28 0 -- -- --

Carbaryl .003 28 17.9 ld E .013 E .031

Carbofuran .003 28 0 -- -- --

Chlorpyrifos .004 28 17.9 ld .021 .106

Cyanazine .004 28 50.0 ld .091 .113

DCPA .002 28 14.3 ld E .001 E .002

DDE, p,p’ .006 28 0 -- -- --

Diazinon .002 28 32.1 ld .049 .092

Dieldrin .001 28 0 -- -- --

Diethylanaline-2,6 .003 28 0 -- -- --

Disulfoton .017 28 0 -- -- --

EPTC .002 28 0 -- -- --

Ethalfluralin .004 28 0 -- -- --

Ethoprop .003 28 0 -- -- --

Fonofos .003 28 0 -- -- --

HCH, alpha .002 28 0 -- -- --

HCH, gamma .004 28 0 -- -- --

Linuron .002 28 3.6 ld ld .054

Malathion .005 28 3.6 ld ld .008

Metolachlor .002 28 100 .105 1.37 1.51

Metribuzin .004 28 28.6 ld .073 .120

Molinate .004 28 0 -- -- --

Napropamide .003 28 0 -- -- --

Parathion .004 28 0 -- -- --

Parathion, methyl .006 28 0 -- -- --

Pebulate .004 28 0 -- -- --

Pendimethalin .004 28 0 -- -- --

Permethrin, cis .005 28 0 -- -- --

Phorate .002 28 0 -- -- --

Prometon .003 28 75.0 .008 .044 .055

Pronamide .003 28 0 -- -- --

Propachlor .007 28 0 -- -- --

Propanil .004 28 0 -- -- --

Propargite .013 28 0 -- -- --

Simazine .005 28 89.3 .023 .167 .177

Tebuthiuron .010 28 0 -- -- --

Terbacil .007 28 3.6 ld ld E .014

Terbufos .013 28 0 -- -- --

Thiobencarb .002 28 0 -- -- --

Triallate .001 28 0 -- -- --

Trifluralin .002 28 0 -- -- --
66 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Table B7. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the St. Joseph River near Newville, Ind.

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 35 82.9 0.012 4.68 5.61

Alachlor .002 35 97.1 .023 3.43 4.94

Atrazine .001 35 100 .357 17 E23

Atrazine, deethyl .002 35 100 E .045 E .479 E .510

Azinphos, methyl .001 34 0 -- -- --

Benfluralin .002 35 2.9 ld ld E .003

Butylate .002 35 2.9 ld ld E .002

Carbaryl .003 35 0 -- -- --

Carbofuran .003 35 2.9 ld ld E .004

Chlorpyrifos .004 34 22.9 ld .020 E .211

Cyanazine .004 35 100 .081 4.68 4.75

DCPA .002 35 17.1 ld E .002 E .005

DDE, p,p’ .006 35 0 -- -- --

Diazinon .002 35 14.3 ld .007 .007

Dieldrin .001 35 0 -- -- --

Diethylanaline-2,6 .003 35 2.9 ld ld E .001

Disulfoton .017 35 0 -- -- --

EPTC .002 35 2.9 ld ld E .002

Ethalfluralin .004 35 0 -- -- --

Ethoprop .003 35 0 -- -- --

Fonofos .003 35 0 -- -- --

HCH, alpha .002 35 0 -- -- --

HCH, gamma .004 35 0 -- -- --

Linuron .002 35 28.6 ld .394 .434

Malathion .005 35 2.9 ld ld .011

Metolachlor .002 35 100 .270 12 14

Metribuzin .004 35 82.9 .019 1.62 2.02

Molinate .004 35 0 -- -- --

Napropamide .003 35 0 -- -- --

Parathion .004 35 0 -- -- --

Parathion, methyl .006 35 0 -- -- --

Pebulate .004 35 0 -- -- --

Pendimethalin .004 35 8.6 ld .015 .152

Permethrin, cis .005 35 0 -- -- --

Phorate .002 35 0 -- -- --

Prometon .003 35 74.3 .010 .065 .210

Pronamide .003 35 0 -- -- --

Propachlor .007 35 0 -- -- --

Propanil .004 35 0 -- -- --

Propargite .013 35 0 -- -- --

Simazine .005 35 100 .042 1.4 2.16

Tebuthiuron .010 35 48.6 ld .040 .070

Terbacil .007 35 0 -- -- --

Terbufos .013 35 0 -- -- --

Thiobencarb .002 35 0 -- -- --

Triallate .001 35 0 -- -- --

Trifluralin .002 35 2.9 ld ld E .001
Compounds Analyzed 67

Table B8. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the Cuyahoga River at Cleveland, Ohio

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 28 25.0 ld 0.122 0.198

Alachlor .002 28 25.0 ld .021 .027

Atrazine .001 28 100 .063 .572 .761

Atrazine, deethyl .002 28 96.4 E .013 E .038 E .038

Azinphos, methyl .001 28 0 -- -- --

Benfluralin .002 28 0 -- -- --

Butylate .002 28 0 -- -- --

Carbaryl .003 28 42.9 ld E .110 E .143

Carbofuran .003 28 0 -- -- --

Chlorpyrifos .004 28 46.4 ld .023 .025

Cyanazine .004 28 35.7 ld .080 .126

DCPA .002 28 14.3 ld E .002 E .003

DDE, p,p’ .006 28 0 -- -- --

Diazinon .002 28 92.9 .036 .160 .290

Dieldrin .001 28 0 -- -- --

Diethylanaline-2,6 .003 28 0 -- -- --

Disulfoton .017 28 0 -- -- --

EPTC .002 28 3.6 ld ld E .004

Ethalfluralin .004 28 0 -- -- --

Ethoprop .003 28 0 -- -- --

Fonofos .003 28 0 -- -- --

HCH, alpha .002 28 0 -- -- --

HCH, gamma .004 28 0 -- -- --

Linuron .002 28 0 -- -- --

Malathion .005 28 14.3 ld .015 .016

Metolachlor .002 28 100 .021 .266 .386

Metribuzin .004 28 3.6 ld ld .030

Molinate .004 28 0 -- -- --

Napropamide .003 28 0 -- -- --

Parathion .004 28 0 -- -- --

Parathion, methyl .006 28 0 -- -- --

Pebulate .004 28 0 -- -- --

Pendimethalin .004 28 3.6 ld ld .021

Permethrin, cis .005 28 0 -- -- --

Phorate .002 28 0 -- -- --

Prometon .003 28 96.4 .038 .135 .162

Pronamide .003 28 0 -- -- --

Propachlor .007 28 0 -- -- --

Propanil .004 28 0 -- -- --

Propargite .013 28 0 -- -- --

Simazine .005 28 71.4 .012 .063 .064

Tebuthiuron .010 28 21.4 ld .016 .030

Terbacil .007 28 3.6 ld ld E .014

Terbufos .013 28 0 -- -- --

Thiobencarb .002 28 0 -- -- --

Triallate .001 28 0 -- -- --

Trifluralin .002 28 10.7 ld .006 E .007
68 Occurrence, Distribution, Loads of Selected Pesticides, Lake Erie-Lake St. Clair Basin, 1996–98

Table B9. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the Maumee River at New Haven, Ind.

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 29 75.9 0.014 4.58 8.88

Alachlor .002 29 96.5 .027 2.54 3.63

Atrazine .001 29 100 .485 E28 E37

Atrazine, deethyl .002 29 100 E .052 E .738 E 1.09

Azinphos, methyl .001 28 0 -- -- --

Benfluralin .002 29 3.4 ld ld E .004

Butylate .002 29 0 -- -- --

Carbaryl .003 29 31.0 ld E .033 E .141

Carbofuran .003 29 10.3 ld E .044 E .188

Chlorpyrifos .004 28 27.6 ld .045 .092

Cyanazine .004 29 100 .115 5.53 5.97

DCPA .002 29 10.3 ld .002 .006

DDE, p,p’ .006 29 0 -- -- --

Diazinon .002 29 55.2 .006 .130 .201

Dieldrin .001 29 0 -- -- --

Diethylanaline-2,6 .003 29 0 -- -- --

Disulfoton .017 29 0 -- -- --

EPTC .002 29 3.4 ld ld .010

Ethalfluralin .004 29 0 -- -- --

Ethoprop .003 29 0 -- -- --

Fonofos .003 29 3.4 ld ld .005

HCH, alpha .002 29 0 -- -- --

HCH, gamma .004 29 0 -- -- --

Linuron .002 29 20.7 ld .077 .438

Malathion .005 29 10.3 ld .007 .009

Metolachlor .002 29 100 .395 18 E23

Metribuzin .004 29 72.4 .032 1.25 1.69

Molinate .004 29 0 -- -- --

Napropamide .003 29 0 -- -- --

Parathion .004 29 0 -- -- --

Parathion, methyl .006 29 0 -- -- --

Pebulate .004 29 0 -- -- --

Pendimethalin .004 29 13.8 ld .094 .142

Permethrin, cis .005 29 0 -- -- --

Phorate .002 29 0 -- -- --

Prometon .003 29 89.7 .026 .220 .248

Pronamide .003 29 0 -- -- --

Propachlor .007 29 0 -- -- --

Propanil .004 29 0 -- -- --

Propargite .013 29 0 -- -- --

Simazine .005 29 100 .063 2.25 3.00

Tebuthiuron .010 29 48.3 ld .093 .155

Terbacil .007 29 0 -- -- --

Terbufos .013 29 0 -- -- --

Thiobencarb .002 29 0 -- -- --

Triallate .001 29 0 -- -- --

Trifluralin .002 29 10.3 ld .004 .006
Compounds Analyzed 69

Table B10. Compounds analyzed; method detection limit; number of analyses; frequency of detection; and the median,

95th percentile, and maximum concentrations for samples from the Maumee River at Waterville, Ohio

[μg/L, micrograms per liter; ld, less than method detection limit; E, pesticides detected and concentrations estimated; --, no data]

Compound

Method

detection limit

(μg/L)

Number

of

analyses

Frequency

of

detection

(percent)

Median

(μg/L)

95th

percentile

(μg/L)

Maximum

(μg/L)

Acetochlor 0.002 33 93.9 0.026 6.68 10.6

Alachlor .002 33 97.0 .036 4.34 6.70

Atrazine .001 33 100 .337 E21 E22

Atrazine, deethyl .002 33 100 E .084 E .763 E 1.02

Azinphos, methyl .001 33 0 -- -- --

Benfluralin .002 33 3.0 ld ld E .002

Butylate .002 33 6.1 ld .001 .005

Carbaryl .003 33 12.1 ld E .026 E .084

Carbofuran .003 33 9.1 ld E .079 E .247

Chlorpyrifos .004 32 42.4 ld .025 .030

Cyanazine .004 33 100 .096 9.92 9.97

DCPA .002 33 15.2 ld E .001 E .003

DDE, p,p’ .006 33 0 -- -- --

Diazinon .002 33 66.7 .005 .022 .023

Dieldrin .001 33 6.1 ld .004 .009

Diethylanaline-2,6 .003 33 6.1 ld E .002 E .002

Disulfoton .017 33 0 -- -- --

EPTC .002 33 12.1 ld E .004 E .004

Ethalfluralin .004 33 0 -- -- --

Ethoprop .003 33 0 -- -- --

Fonofos .003 33 0 -- -- --

HCH, alpha .002 33 3.0 ld ld E .004

HCH, gamma .004 33 0 -- -- --

Linuron .002 33 24.2 ld .055 .370

Malathion .005 33 3.0 ld ld .008

Metolachlor .002 33 100 .372 17 20

Metribuzin .004 33 87.9 .052 3.50 4.92

Molinate .004 33 0 -- -- --

Napropamide .003 33 0 -- -- --

Parathion .004 33 0 -- -- --

Parathion, methyl .006 33 3.0 ld ld .008

Pebulate .004 33 0 -- -- --

Pendimethalin .004 33 12.1 ld .039 .064

Permethrin, cis .005 33 0 -- -- --

Phorate .002 33 0 -- -- --

Prometon .003 33 87.9 .020 .114 .128

Pronamide .003 33 0 -- -- --

Propachlor .007 33 3.0 ld ld .008

Propanil .004 33 0 -- -- --

Propargite .013 33 0 -- -- --

Simazine .005 33 97.0 .047 1.84 1.99

Tebuthiuron .010 33 78.8 .016 .066 .090

Terbacil .007 33 0 -- -- --

Terbufos .013 33 0 -- -- --

Thiobencarb .002 33 0 -- -- --

Triallate .001 33 0 -- -- --

Trifluralin .002 33 12.1 ld .002 .005