Pesticides Detected in Urban Streams During Rainstorms 

in King and Snohomish Counties, Washington, 1998

Prepared in cooperation with 

WASHINGTON STATE DEPARTMENT 

OF ECOLOGY

By Frank D. Voss and Sandra S. Embrey

BRITISH COLUMBIA

C_ANADA_ 

UNITED STATES

Puget Sound Basin

National Water-Quality Assessment Study Unit

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 00-4098

Pesticides Detected in Urban Streams During 

Rainstorms in King and Snohomish Counties, 

Washington, 1998

By Frank D. Voss and Sandra S. Embrey

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 00-4098

Prepared in cooperation with

WASHINGTON STATE DEPARTMENT OF ECOLOGY

Tacoma, Washington 

2000
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Charles G. Groat, Director

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

only and does not constitute endorsement by the U.S. Geological Survey.

For additional information write to:

District Chief

U.S. Geological Survey

1201 Pacific Avenue, Suite 600

Tacoma, Washington 98402

Copies of this report can be purchased 

from:

U.S. Geological Survey 

Information Services 

Box 25286 

Federal Center 

Denver, CO 80225
FOREWORD

The mission of the U.S. Geological Survey 

(USGS) is to assess the quantity and quality of the earth 

resources of the Nation and to provide information that 

will assist resource managers and policymakers at 

Federal, State, and local levels in making sound 

decisions. Assessment of water-quality conditions and 

trends is an important part of this overall mission.

One of the greatest challenges faced by waterresources scientists is acquiring reliable information that 

will guide the use and protection of the Nation's water 

resources. That challenge is being addressed by Federal, 

State, interstate, and local water-resource agencies and 

by many academic institutions. These organizations are 

collecting water-quality data for a host of purposes that 

include: compliance with permits and water-supply 

standards; development of remediation plans for a 

specific contamination problem; operational decisions 

on industrial, wastewater, or water-supply facilities; and 

research on factors that affect water quality. An 

additional need for water-quality information is to 

provide a basis on which regional and national-level 

policy decisions can be based. Wise decisions must be 

based on sound information. As a society we need to 

know whether certain types of water-quality problems 

are isolated or ubiquitous, whether there are significant 

differences in conditions among regions, whether the 

conditions are changing over time, and why these 

conditions change from place to place and over time. 

The information can be used to help determine the 

efficacy of existing water-quality policies and to help 

analysts determine the need for and likely consequences 

of new policies.

To address these needs, the Congress appropriated funds in 1986 for the USGS to begin a pilot 

program in seven project areas to develop and refine the 

National Water-Quality Assessment (NAWQA) 

Program. In 1991, the USGS began full implementation 

of the program. The NAWQA Program builds upon an 

existing base of water-quality studies of the USGS, as 

well as those of other Federal, State, and local agencies. 

The objectives of the NAWQA Program are to:

 Describe current water-quality conditions for a 

large part of the Nation's freshwater streams, 

rivers, and aquifers.

 Describe how water quality is changing over time.

 Improve understanding of the primary natural and 

human factors that affect water-quality conditions.

This information will help support the development and evaluation of management, regulatory, and 

monitoring decisions by other Federal, State, and local 

agencies to protect, use, and enhance water resources.

The goals of the NAWQA Program are being 

achieved through ongoing and proposed investigations 

of more than 50 of the Nation's most important river 

basins and aquifer systems, which are referred to as 

study units. These study units are distributed throughout 

the Nation and cover a diversity of hydrogeologic 

settings. More than two-thirds of the Nation's freshwater use occurs within these study units and more than 

two-thirds of the people served by public water-supply 

systems live within their boundaries.

National synthesis of data analysis, based on 

aggregation of comparable information obtained from 

the study units, is a major component of the program. 

This effort focuses on selected water-quality topics 

using nationally consistent information. Comparative 

studies will explain differences and similarities in 

observed water-quality conditions among study areas 

and will identify changes and trends and their causes. 

The first topics addressed by the national synthesis are 

pesticides, nutrients, volatile organic compounds, and 

aquatic biology. Discussions on these and other waterquality topics will be published in periodic summaries 

of the quality of the Nation's ground and surface water 

as the information becomes available.

This report is an element of the comprehensive 

body of information developed as part of the NAWQA 

Program. The program depends heavily on the advice, 

cooperation, and information from many Federal, State, 

interstate, Tribal, and local agencies and the public. The 

assistance and suggestions of all are greatly appreciated.

Robert M. Hirsch 

Chief Hydrologist
CONTENTS

Abstract...........................................................^ 1

Introduction.............................................^ 1

Purpose and scope....................................................................................................................................................... 2

Description of the study area ...................................................................................................................................... 2

Acknowledgments...............................................................................................................................................^ 3

Methods.............................................................................................................^ 3

Sample collection and processing............................................................................................................................... 4

Laboratory procedures................................................................................................................................................ 6

Method for collecting pesticide retail sales data......................................................................................................... 7

General water-quality findings.............................................................................................................................................. 7

Pesticides detected in stream-water samples............................................................................................................... 7

Pesticide concentrations and aquatic criteria.............................................................................................................. 7

Relating general water-quality findings to retail sales of pesticides..................................................................................... 12

The retail sales database.............................................................................................................................................. 12

Pesticides sold in retail stores and detected in stream-water samples ........................................................................ 12

Pesticides sold in retail stores but not detected in stream-water samples................................................................... 14

Pesticides not sold in retail stores but detected in stream-water samples................................................................... 14

Pesticides not sold in retail stores and not detected in stream-water samples............................................................ 16

Pesticides sold in retail stores but not assessed........................................................................................................... 16

Implications of this study for future research ....................................................................................................................... 16

Summary .................................................................................................................................................................^ 17

References cited ...............................................................................................................................................................~ 18

Appendix A. Pesticides analyzed by the USGS in this study and their method detection limits ......................................... 21

Appendix B. Nitrogen-containing pesticides analyzed by the Washington State Department of Ecology

in this study and their quantitation limits................................................................................................................ 22

Appendix C. Chlorinated herbicides analyzed for by the Washington State Department of Ecology

in this study and their quantitation limits................................................................................................................ 22

FIGURES

1. Map showing locations of sampling sites within watersheds, King and Snohomish Counties, Washington............. 2

2. Conceptual diagram of desired relation between discharge and sample collection................................................... 4

3. Hydrographs for streams sampled during the storm on April 23, 1998, King County, Washington ......................... 5

4. Hydrographs for streams sampled during the storm on May 14, 1998, King and

Snohomish Counties, Washington.............................................................................................................................. 5

5. Hydrographs for streams sampled during the storm on May 25, 1998, King County, Washington .......................... 6

6. Concentrations of detected pesticides and their relations to criteria to protect aquatic life....................................... 11

7. Units of pesticide sold in 1997 at 10 home and garden stores located in western King and

south Snohomish Counties................................................ 13

8. Comparisons of units of pesticides sold with the percentage of study watersheds where pesticide

detections occurred, King and Snohomish Counties, Washington, 1998................................................................... 15

IV
TABLES

1. Land use in study watersheds, King and Snohomish Counties, Washington......................................................... 3

2. Sampling locations and storm dates, King and Snohomish Counties, Washington, 1998 ..................................... 4

3. Pesticides and pesticide transformation products detected at sample sites, King and Snohomish Counties,

Washington, 1998 ............................................................................................................................................ 8

4. Concentrations of all pesticides and pesticide transformation products detected in stream-water samples,

King and Snohomish Counties, Washington, 1998 ................................................................................................ 9

5. Pesticides with retail sales and detected in stream-water samples, King and Snohomish Counties,

Washington, 1998 ............................................................................................................................................ 12

6. Pesticides with retail sales and not detected in stream-water samples, King and Snohomish Counties,

Washington, 1998...............................................................................................................^ 14

7. Pesticides with no retail sales but detected in stream-water samples, King and Snohomish Counties,

Washington, 1998 ...................................................................^^ 14

8. Pesticides with no retail sales and not detected in stream-water samples, King and Snohomish Counties,

Washington, 1998 ............................................................................................................................................ 16

9. Pesticides and other compounds with retail sales that were not sampled for, King and Snohomish Counties,

Washington, 1998................................................................................................................................................... 17

Pesticides Detected in Urban Streams During 

Rainstorms in King and Snohomish Counties, 

Washington, 1998

By Frank D. Voss and Sandra S. Embrey

ABSTRACT

The U.S. Geological Survey and the 

Washington State Department of Ecology cooperated in sampling 13 sites in 10 urban watersheds 

during 3 storms in King County, Wash., in the 

spring of 1998. Twenty-six of the 98 pesticides 

and transformation products sampled for were 

detected. Twenty-three of the 26 were pesticides 

(17 herbicides, 5 insecticides, and 1 fungicide), 

and 3 were transformation products. The pesticides dichlobenil, 2,4-D, MCPP, Diazinon, and 

pentachlorophenol were detected at all of the 

urban study sites.

Samples of 5 of 14 detected pesticides with 

maximum concentration limits exceeded those 

limits-the insecticides carbaryl, chlorpyrifos, 

Diazinon, Lindane, and Malathion. The concentrations of 3 of 11 pesticides with chronic aquaticlife criteria exceeded the limits-Lindane, 

Diazinon, and carbaryl.

Twelve pesticides detected in stream-water 

samples were sold in retail stores. Several of these 

pesticides-2,4-D, dichlobenil, Diazinon, and 

MCPP-were detected in all the sampled streams, 

possibly because of their high retail sales. Retail 

sales might also explain why other pesticides 

(such as prometon and triclopyr) are frequently 

detected.

Five pesticides were sold in retail stores but 

were not detected in stream-water samples-two 

insecticides (cw-permethrin and disulfoton), two 

fungicides (chlorothalonil and triadimefon), and 

one herbicide (pendimethalin).

The pesticides not sold in retail stores but 

detected in stream-water samples probably originate from applications to nonresidential areas 

(roadsides, playing fields, and parks) by local 

governments. Detected pesticides sold in a small 

number of units (prometon, triclopyr, MCPA) also 

may be from nonresidential rather than residential 

applications.

INTRODUCTION

Each year in the Puget Sound Basin, urban and 

residential areas are treated with a variety of pesticides. 

Storm-water runoff transports these pesticides to 

streams, sometimes causing pesticide concentrations to 

reach levels that may cause adverse ecological effects.

As the population of the Puget Sound Basin 

increases and urban and residential areas expand, 

pesticides will probably be used increasingly. However, understanding how pesticide usage affects water 

quality and potentially affects aquatic habitat can lead 

to managing pesticide applications better and minimizing potential adverse impacts on streams in urban 

watersheds.
t wr wm

Purpose and Scope

This report presents the results of a study to 

assess the occurrence and concentrations of pesticides 

in urban stream-water sampled during spring storms 

and to infer sources of pesticides by

 sampling for 98 pesticides and pesticide transformation products during rain storms in April and May 

of 1998 at 13 sites in 11 watersheds in western 

King and Snohomish Counties;

 compiling sampling data into a database and 

examining where pesticides were detected;

 examining the concentrations of pesticides in

stream-water and comparing these concentrations

with criteria for the protection of aquatic life set by 

the National Academy of Sciences and the 

National Academy of Engineering (NAS/NAE), 

the U.S. Environmental Protection Agency 

(USEPA), and other agencies; and

comparing the sample data to pesticide sales data 

and land-use information to try to determine possible sources of pesticides found in stream water.

Description of the Study Area

This study was conducted in western King and 

south Snohomish Counties, both located in western 

Washington (fig. 1). Western King and south Snohomish Counties are in a heavily developed urban/

122°22'30" 122°

Lvon

Cree/rXSNOHOMISH COUNTY

' SouWFork 

Co / Thtffnton 

Crdek

Base from U.S. Geological Survey digital data, 1: 2,000,000, 1972

Albers Conic Equal-Area Projection CVDI AMATIOM

D Puget Sound Basin

 Study area 

O Watershed

Roads 

~"~ County boundary

* Sampling site

Figure 1. Locations of sampling sites within watersheds, King and 

Snohomish Counties, Washington.
suburban environment that includes much of the 

greater Seattle metropolitan area. Temperatures are 

fairly mild throughout the year. The average daily high 

and low temperatures in January are 45°F (degrees 

Fahrenheit) and 35.1°F, and the average daily high and 

low temperatures in July are 75.2°F and 55.2°F (Beautiful Seattle.com, 1999). The mean annual precipitation in Seattle is 37 inches per year.

The land use in 10 of the 11 watersheds selected 

for pesticide sampling consists of varying mixtures of 

dense urban housing, tracts of suburban single-family 

housing, commercial strips and malls, and industrial 

complexes. One of the 11 watersheds (Rock Creek) is 

forested and was sampled to test for pesticides in an 

undeveloped watershed. Natural drainage in most of 

the watersheds has been altered for storm-water management, making it difficult to delineate exact drainage 

areas. Estimated watershed areas in this study (table 1) 

range from approximately 1.8 square miles (Rock 

Creek) to 11.3 square miles (Thornton Creek).

Acknowledgments

We acknowledge and thank the following people 

for their contributions to this study. Dale A. Davis 

from the Washington State Department of Ecology 

(Ecology) and Jim Ebbert and Sandra Embrey from the 

U.S. Geological Survey (USGS) performed site reconnaissance. Bob Black, Jim Ebbert, Sandra Embrey, 

Ralph Embrey (volunteer), Joe Gilbert, Kathy Greene, 

Allan Haggland, Gary Holloway, Emily Inkpen, Greg 

Justin, Stephanie Leisle, Ann Vanderpool from the 

USGS and Dale A. Davis, Art Johnson, Art Larson, 

Pam Marti, Dave Serdar from Ecology performed 

storm sampling, often working under adverse conditions. James Lyles, Deanna Walth, Connie Dean, and 

Ginger Renslow from the USGS performed editing and 

report publication.

METHODS

The following section discusses USGS and 

Ecology methods for collecting and processing field 

samples, processing samples in the laboratory, and 

collecting pesticide retail sales data.

Table 1. Land use in study watersheds, King and Snohomish Counties, Washington

[NF, north fork; SF, south fork; Built-up, comprised of areas of intensive use with much of the land covered by

structures (Anderson and others, 1976)]

Watershed name

Des Moines Creek

Miller Creek

Little Soos Creek

Longfellow Creek 

Rock Creek

Valley Creek 

Sunset Creek

Juanita Creek

Lewis Creek

Lyon Creek 

NF Thornton Creek

SF Thornton Creek

Thornton Creek

Station 

identifier

12103324

12103326

12109550

12113488 

12117695

12119795 

12119900

12120480

12121750

12127290 

12127700

12127800

12128000

Watershed 

area (square 

miles)

6.0

8.6

3.4

2.2 

1.8

2.1 

2.1

3.4

1.9

3.6 

3.1

3.4

11.3

Percent land use in watershed

Built-up

98.3

97.2

60.2

100.0 

0.0

86.5 

100.0

100.0

36.8

99.5 

100.0

100.0

100.0

Agriculture

0.0

0.0

1.0

0.0 

0.0

0.0 

0.0

0.0

0.0

0.0 

0.0

0.0

0.0

Wooded

1.3

2.1

37.8

0.0 

100.0

13.5 

0.0

0.0

63.2

0.0 

0.0

0.0

0.0

Water

0.3

0.7

1.1

0.0 

0.0

0.0 

0.0

0.0

0.0

0.5 

0.0

0.0

0.0

Land-use categories assigned following the method of Hitt, 1995.
o

O

LU

.CO

50

40

00

m

20

10

0 

3:00 AM

Stream-water sample 

collected

6:00 AM 9:00 AM 12:OOPM 3:00 PM

TIME

Figure 2. Conceptual diagram of desired relation between discharge 

and sample collection.

Sample Collection and Processing

The USGS and Ecology cooperated in sampling 

13 sites in 11 watersheds during storms in the spring of 

1998. Streams were sampled during spring because it 

was believed that more pesticides would be detected 

and their concentrations would be higher than at other 

times of the year. This assumption was based on 

pesticide sales data from King County showing that 

pesticide sales were highest during the spring (Market 

Trends Incorporated, 1996). From these sales statistics, it was assumed that these pesticides were being 

purchased for immediate use. It was also assumed that 

the number of pesticides detected and their concentrations would be the highest during storms. This assumption was based on previous sampling of Thornton 

Creek (sampled about 40 times from March 1996 

through May 1998) showing that the number of 

pesticides detected and their concentrations often were 

higher during periods of storm runoff.

The study team determined that taking three 

samples per stream was the best compromise between 

characterizing pesticide concentrations in streams and 

staying within the study's budget. The study design 

specified collecting the three samples while the stream 

was rising during storms, thus capturing the storm 

runoff believed to carry the greatest amount of transportable pesticides. Figure 2 depicts the desired 

relation between the amount of discharge and the times 

when samples should be collected. As shown in this 

figure, the samplers should arrive while the stream is at 

base flow. As the flow in the stream increases slightly 

due to inflow from runoff, the first sample should be 

collected. Another sample should be collected as the

flow continues to increase. Finally, the last sample is 

collected at the storm-runoff peak.

In this study, samples were collected within the 

watersheds during three storms. Table 2 shows the 

locations and dates. While three samples were taken at 

most of the study sites, varying storm intensity and the 

timing of the resulting storm runoff caused variations 

in the numbers of samples taken at some sites (figs. 3, 

4, and 5). For example, two samples were taken at 

Lyon Creek, Thornton Creek, and South Fork Thornton 

Creek, and four samples were taken at Des Moines 

Creek and Little Soos Creek. Single samples were 

taken at Sunset Creek and Lewis Creek on April 10, 

1997, because the storm failed to produce significant 

runoff. A single sample was also taken at the reference 

site, Rock Creek.

Table 2. Sampling locations and storm dates, King and 

Snohomish Counties, Washington, 1998

Sampling locations Storm date

Juanita Creek, Sunset Creek,

Valley Creek, and Lewis Creek April 23, 1998

Lyon Creek, North Fork Thornton

Creek, South Fork Thornton Creek,

and Thornton Creek May 14, 1998

Des Moines Creek, Miller Creek,

Longfellow Creek, Little Soos Creek,

and Rock Creek May 14, 1998
O

O

LU

. W

UJ rr

Ouj

<H&u w u_

Qg

m

^ 

o

30

20

10

Juanita Creek Valley Creek

Lewis Creek

0 i . , . . 0 

12:OOPM 3:00 PM 6:00 PM 9:00 PM 12:00 AM 12:OOPM 3:00 PM 6:00 PM

APRIL 23, 1998

Note: Lewis and Sunset Creeks were each 

sampled once on April 10 but not included in 

these samples because they were not part of 

the April 23 storm.

EXPLANATION

A Stream-water sample collected 

* Stream discharge reading recorded

12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM 

7 i , , , i 8 

6 * Sunset Creek - 7 

5 - /V - - 6 

4 

3 

2 

1

9:00 PM

Figure 3. Hydrographs for streams sampled during the storm on April 23, 1998, King County, 

Washington.

LU

O 

CC

<

O

CO 

Q

Q

Z 

O

o

LJJ 

CO

rrLU

0-

t

LU

LL 

O 

00

D 

O

z

u.o

0.4

0.3

0.2 

0.1.

0

1 1 1

A»-~A. Lyon Creek

f r \

»* ' / X '

- ^ X

i i i

o.u

4.6

4.2

3.8 

3.4

3.0

North Fork of

Thornton Creek fA

yn^Vj 

A

V

« r* \* * »

3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 3:00 AM 6:00 AM 9:00 AM 12:OOPM

% 

94 

92

90 

88

86

84

82

80

"7Q

\ Thornton Creek /*

; / ;

/

A*

f*

I

t * *** i

Data not available for the

South Fork of Thornton Creek

/o 

12:00 AM 3:00 AM 6:00 AM 9:00 AM

MAY 1 4, 1 998 EXPLANATION

A Stream-water sample collected 

» Stream discharge reading recorded

Figure 4. Hydrographs for streams sampled during the storm on May 14,1998, King and Snohomish 

Counties, Washington.
12:00 AM

0 

6:00 PM 9:00 PM 12:00 AM 3:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM 3:00 AM

MAY 25, 1998

EXPLANATION 

' A Stream-water sample collected 

' * Stream discharge reading recorded

Figure 5. Hydrographs for streams sampled during the storm on May 25,1998, King County, 

Washington.

A sample representative of the flow in the stream 

cross-section was obtained by mixing depth-integrated 

samples collected at equally spaced verticals across the 

stream in a glass carboy. Samples were collected using 

the U.S. DH-81 sampler as described by Edwards and 

Glysson (1988) and Shelton (1994). The sampler holds 

a 3-liter Teflon sample bottle, and all parts of the 

sampler coming into contact with sample water are 

constructed of Teflon. All equipment used to collect 

and process samples was cleaned with a 0.2-percent 

nonphosphate detergent, rinsed with deionized water, 

rinsed with pesticide-grade methanol, air dried, 

wrapped in aluminum foil, and stored in a dust-free 

environment prior to sample collection (Shelton, 

1994). The composite sample in the glass carboy was 

split into individual samples for analysis at the USGS 

and Ecology laboratories using a Teflon cone splitter 

(Shelton, 1994).

One of the split samples was filtered through a 

0.7-um (micrometer) glass-fiber filter and passed 

through a C-18 solid-phase extraction (SPE) cartridge 

to extract pesticide compounds. The SPE cartridge was

stored in amber pesticide-free vials at less than 

4 degrees Celsius and shipped to the USGS National 

Water Quality Laboratory (NWQL) in Arvada, Colo. 

The equipment required and the procedures used to 

collect, process, and extract the sample using the SPE 

method are described in Shelton (1994) and Sandstrom 

and others (1992).

Samples analyzed by Ecology's Manchester 

Environmental Laboratory were collected from the 

cone splitter in glass bottles, but were not filtered. 

They were stored on ice during transport to the 

laboratory in Manchester, Wash.

Three field blanks (one per storm) were collected 

for quality assurance of the stream-water samples. No 

pesticides were detected in the field blanks.

Laboratory Procedures

Samples were analyzed for 98 pesticides and 

pesticide transformation products, which required 

three different analytical methods. The USGS laboratory analyzed for several types of pesticides (Appendix
A) using gas chromatography/mass spectrometry 

(Zaugg and others, 1995). The Ecology laboratory 

analyzed for 73 chlorinated herbicides and nitrogencontaining pesticides (Appendices B and C). Chlorinated herbicides and nitrogen-containing pesticides 

were analyzed using Draft EPA Method 8085, which 

uses capillary column GC analysis with an atomic 

emission detector (AED) and ion-trap GC/MS confirmation (Davis, 1998).

No analytes of interest were detected in any of 

the method blanks at the USGS and Ecology laboratories. Precision data were obtained for a set of replicate 

samples. Concentration differences ranged from 0.0 to 

40.0 percent as measured by relative percent difference. No modifications were made to the data set based 

on these results. Surrogate recoveries for pesticide 

analysis by GC/MS indicate that the process was 

acceptably precise and accurate for the pesticide families represented. Quality-control methods for the 

USGS and Ecology laboratories are documented by 

Wagner and others, 1996, and by Davis, 2000.

There was some overlap of compounds analyzed 

by the USGS and Ecology laboratories, which provided additional quality assurance. In cases of overlap, 

the value reported by the USGS laboratory was 

included in the database for analysis because of lower 

reporting levels.

Data returned from the laboratories were 

aggregated into a database and analyzed by the USGS. 

The original data sets can be accessed at http:// 

wa.water.usgs.gov/ps.data.html.

Method for Collecting Pesticide 

Retail Sales Data

Data for 1997 pesticide sales were purchased by 

the King County Hazardous Waste Management 

Program from a firm that collects marketing information from home and garden stores in western Washington. All the large home and garden stores (nine stores) 

in western King County and one store in south 

Snohomish County were selected. The stores are 

widely distributed throughout the study area.

GENERAL WATER-QUALITY FINDINGS

The following section discusses the pesticides 

detected in stream-water samples and how the concentrations relate to criteria to protect aquatic life.

Pesticides Detected in Stream-Water 

Samples

Twenty-six of the 98 pesticides and transformation products sampled for were detected (table 3). 

Three of the 26 compounds detected were transformation products of other pesticides (desethylatrazine is a 

transformation product of atrazine, 4-nitrophenol is a 

transformation product of methyl parathion, and 

2,6-dichlorobenzamide is a transformation product of 

dichlobenil). In this report a transformation product is 

not counted as a detected pesticide because it cannot be 

directly related to the pesticide sales database. Of the 

23 detected pesticides, 17 were herbicides, 5 were 

insecticides, and 1 was a fungicide. The herbicides 

2,4-D, dichlobenil, MCPP, and prometon; the insecticide Diazinon; and the fungicide pentachlorophenol 

were detected at all of the urban sites. The watershed 

with the greatest number of pesticides detected (17) 

was Juanita Creek. The watershed with the least 

number of pesticides detected was Little Soos Creek, 

with eight pesticides detected. The reference site, 

Rock Creek, was sampled to show which pesticides 

would be found in stream water if urban development 

was absent. None of the pesticides studied were 

detected in Rock Creek.

Pesticide Concentrations and 

Aquatic Criteria

Table 4 lists the concentrations of pesticides and 

pesticide transformation products detected by watershed and sample. Figure 6 shows concentrations of 

detected pesticides and their relation to criteria to 

protect aquatic life. Criteria are not established for the 

transformation products. Fourteen of the pesticides 

detected in this study have maximum recommended 

concentration limits for the protection of aquatic life 

established by the National Academy of Sciences and 

National Academy of Engineering (1973) or the Ministers of Health Canada and Environment Canada (1995). 

The limits were exceeded in sample concentrations of 

five insecticides-carbaryl, chlorpyrifos, Diazinon, 

Lindane, and Malathion (fig. 6). Eleven of the pesticides detected in this study have chronic aquatic-life 

criteria recommended by Norris and Dost (1991), the 

U.S. Environmental Protection Agency (1998), and 

others. These limits were exceeded by concentrations 

of Lindane, Diazinon, and carbaryl. The aquatic-life
SAMPLE SITES

Q

PESTICIDES

2,4-D

4-Nitrophenol* 

Diazinon 

Dichlobenil 

MCPP (Mecoprop) 

Pentachlorophenol 

Prometon 

Trichlopyr 

MCPA 

Atrazine 

Benzamide, 2,6-dichloro-* 

Carbaryl 

Simazine 

Dicamba 

Lindane 

Malathion 

Dichlorprop 

Metolachlor 

Trifluralin 

Desethylatrazine* 

EPTC 

Napropamide 

Acetochlor 

Chlorpyrifos 

Oxadiazon 

Tebuthiuron

Creek Juan/fa 

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

*

5

!

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

Sunset Creek

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

Des Moines Creek

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

North FrkThornto

X

X

X

X

X

X

X

X

X

X

X

X

X

Valley Creek

X

X

X

X

X

X

X

X

X

X

X

X

X

ig

5.CO

q> -j

X

X

X

X

X

X

X

X

X

X

X

X

X

Miller Crek

X

X

X

X

X

X

X

X

X

X

X

X

X

Longfellow Creek

X

X

X

X

X

X

X

X

X

X

X

Thornton Creek

X

X

X

X

X

X

X

X

X

X

X

X

South ForkThornto

X

X

X

X

X

X

X

X

X

X

X

X

Soos Creek Little 

X

X

X

X

X

X

X

X

X

X

X

X

X

X - compound was detected

* - pesticide transformation product

Table 3. Pesticides and pesticide transformation products detected at sample sites, 

King and Snohomish Counties, Washington, 1998.
Table 4. Concentrations of all pesticides and pesticide transformation products detected in stream-water samples, King and Sno

Washington, 1998

[J, Estimated value, Ecology; E, Estimated value, USGS; *, pesticide transformation product; --, no data. All values are in micrograms per liter, \ig/L]

Sample site name

Des Moines Creek

Miller Creek

Little Soos Creek

Longfellow Creek

Valley Creek

Sunset Creek

Juanita Creek

Lewis Creek

Lyon Creek

Thornton Creek

Golf Course

Thornton Creek

South Fork

Thornton Creek

Sample

1

2

3

4

1

2

3

1

2

3

4

1

2

3

1

2

3

1

2

3

1

2

3

1

2

3

1

2

1

2

3

1

2

1

2

2,4-D

0.29

0.11

0.22

J0.01

0.05

0.06

--

--

--

J0.01

0.21

0.17

0.27

0.38

0.33

0.68

0.19

0.59

0.50

1.0

0.63

0.59

J0.03

0.12

0.29

0.14

0.16

0.08

0.07

0.08

0.11

0.11

0.12

2,6-Dichlorobenzamide*

J0.01

J0.01

-

-

J0.04

J0.05

-

-

-

-

-

-

--

-

-

--

-

J0.02

J0.02

--

-

--

--

--

J0.02

J0.04

J0.03

J0.03

J0.02

J0.03

-

J0.02

--

J0.02

J0.02

4-Nitro- Acetophenol* chlor

J0.04

0.07

J0.05

0.12

-

J0.05

0.08

..

..

..

J0.06

J0.05

J0.06 0.01

0.12

..

0.16

0.4

0.24

0.24

0.29

0.25

0.22

0.07

J0.02

J0.05

..

J0.04

J0.04

..

J0.03

0.08

0.08

J0.06

0.08

Atrazine

0.006

E0.004

0.012

0.008

0.006

0.008

--

-

-

--

--

-

-

-

--

-

--

-

0.011

0.006

-

0.004

--

-

E0.002

E0.002

0.019

0.021

0.005

0.006

0.006

-

--

--

E0.004

ChlorCarbaryl pyrifos

E0.046

-.-

..

..

0.02

E0.007 0.02

E0.017

E0.01

..

E0.022

E0.017

..

..

E0.012

E0.01 1

E0.003

-

E0.008

E0.009

..

E0.007

Desethyl- Diazatrazine* inon

0.009

0.036

0.036

..

0.011

0.108

..

-

..

0.157

-.

..

0.046

0.05

0.061

0.055

0.08

E0.005 0.122

0.13

0.242

0.276

0.309

0.238

0.105

E0.002 0.094

0.305

0.425

0.092

0.076

0.061

0.094

0.154

0.139

0.152

Dicam

0.06

-

J0.02

-

-

--

--

--

--

0.05

--

-

--

--

--

-

--

--

0.09

J0.03

0.04

--

--

--

J0.04

J0.02

--

--

--

--

--

--

--
Table 4. Concentrations of all pesticides and pesticide transformation products detected in stream-water samples, King and Snoh

Washington, 1998-Continued

Sample site name

Des Moines Creek

Miller Creek

Little Soos Creek

Longfellow Creek

Valley Creek

Sunset Creek

Juanita Creek

Lewis Creek

Lyon Creek

Thornton Creek

Golf Course

Thornton Creek

South Fork

Thornton Creek

MalaSample Lindane thion

1

2

3

4

1

2

3 -- 0.078

1

2

3

4

1

2

3

1 0.095 0.014

2 0.082

3 0.019

1

2 0.032

3 0.076

1 -- 0.087

2 0.034 0.073

3 0.03 0.071

1

2

3

1 -- 0.033

2 - 0.037

1

2

3

1

2

1

2

MCPA

--

--

0.09

--

--

--

--

--

--

--

0.29

J0.06

--

--

0.08

0.09

0.18

0.15

0.13

0.38

0.12

0.14

--

J0.04

--

--

J0.03

J0.05

--

J0.05

--

J0.03

--

--

Metol- Naprop- OxaMCPP achlor amide diazon

J0.07

0.17 -- -- 0.05

0.18 -- - 0.09

0.27 -- -- JO. 11

0.116

0.2 0.09

0.21 0.141

..

..

0.09

0.18

0.23

0.35

0.27 0.01

0.22 0.008

0.38 0.008

0.31 -- 0.167

0.63 -- 0.884

0.57 -- 0.260

0.74

0.39

0.44 0.004

0.06

0.11

0.13

0.15 -- 0.02

0.13 - 0.01

0.16

0.1

0.11

J0.05

J0.06

0.09

0.11

Pentachlorophenol

0.18

0.069

0.082

0.095

J0.016

0.075

0.076

--

--

-

0.025

0.04

0.062

0.19

0.11

0.059

0.13

-

0.067

0.079

-

0.076

0.077

J0.016

--

--

0.036

0.042

0.032

0.024

0.048

0.03

0.041

0.058

0.078

Prometon

0.035

0.233

0.106

0.124

0.02

0.02

0.055

--

--

--

E0.016

--

0.124

0.049

E0.013

E0.01

E0.013

--

0.03

0.025

0.05

0.087

0.078

.

E0.007

E0.007

0.031

0.042

0.019

0.021

0.062

0.023

0.094

0.071

0.045

Simazine 

..

0.026

-

-

..

-

-

..

..

..

-

..

..

-

..

..

0.008

..

..

0.014

0.026

..

E0.002

..

4.73

4.99

0.013 

0.014 

0.022 

0.211

0.164

0.326

0.549
Active ingredient and trade name1 Freshwater aquatic-life criteria, Concentration, in parts per billion (ppb)

example in parentheses in parts per billion | RMC, recommended maximum concentration

no aquatic-life criteria exist | Chronic aquatic-life criteria

Herbicide Acute Chronic RMC 0.001 0.01 0.1 1 10 100

2,4-D (Weedone)Acetochlor (Guardian)

Atrazine (AAtrex)

Dicamba (Banvel)

Dichlobenil (Casoron)Dichlorprop (2,4-DP)

EPIC (Eptam)

MCPA (Kilsem)

MCPP (Mecoprop)

Metolachlor (Dual)

Napropamide (Devrinol)

Oxadiazon (Ronstar)

Prometon (Pramitol)

Simazine (Princep)

Tebuthiuron (Spike)

Triclopyr (Garlon)Trifluralin (Treflan)

Insecticide

Carbaryl (Sevin)Chlorpyrifos (Dursban)

Diazinon (Diazinon)

gfamma-HCH (Lindane)

Malathion (Malathion)

Fungicide

Pentachlorophenol (Penta)

4 10 -- 4 70

4 390--~------------ 4 100- 45,600--4 0.17

3' 7 0.083

6 0.163 0.95 -- 3,8-, 9

4 1-- 4 7

4 39-------------- 4 10- 4560-- 4 0.017

3-7 0.041

6 0.04

7 0.083 0.1

3,8 1 5

5,24-- 5 2

5 10

2 37---- 5 2.6 -- 5 8------ 2,5-, o---- 5 0.1

2 0.022 0.0012 0.009

2 0.022 0.0085 0.5

' ' """

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O (QD <C

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1 0 3D CE

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1 Use of trade names is for descriptive purposes and does not imply endorsement ^ Ministers of Health Canada and Environment Canada, 1995

by the U.S. Geological Survey, the Department of Ecology, or King County 6 Menconi and Cox, 1994

2 National Academy of Sciences and National Academy of Eng neering, 1973 ' State of Washington, 19923 U.S. Environmental Protection Agency, 1998 ° Criteria are pH dependent; values shown calculated at pH of 7.84 Norris and Dost, 1991 , Table 3

Figure 6. Concentrations of detected pesticides and their relations to criteria to protect aquatic life.
criteria indicate concentrations that may adversely 

affect aquatic organisms. However, the ecological 

effects in the streams sampled are unknown because 

the duration of exposure to the concentrations observed 

and the combined effects of many pesticides in stream 

water are unknown.

RELATING GENERAL WATER-QUALITY 

FINDINGS TO RETAIL SALES OF 

PESTICIDES

The following section discusses how pesticides 

sold in 10 home and garden stores located in urban and 

suburban areas in King and Snohomish Counties relate 

to pesticide detections in the study area watersheds.

The Retail Sales Database

In 1997, King County assembled a database of 

retail pesticide sales to study the pesticides that King 

County residents were purchasing and applying to their 

lawns and gardens. Sales data for 61 pesticides were 

obtained from 10 home and garden stores located in 

urban and suburban areas in King and south Snohomish 

Counties. It was assumed that the sales numbers represent pesticide sales throughout western King County 

because according to a 1996 survey of 1,200 King 

County residents (Market Trends Incorporated, 1996), 

two-thirds of retail pesticide sales are from home and 

garden stores.

The measured quantity was a "unit" or package 

of active ingredient sold. Often two or more active 

ingredients are combined in a package of pesticide. For 

example, if a package contains the active ingredients 

2,4-D and MCPP, these pesticides would be counted in 

the retail pesticide database as one unit sold of 2,4-D 

and one unit sold of MCPP. The total units sold from 

the 10 stores are shown in figure 7.

Estimating the amounts of pesticides applied in 

watersheds was not possible because of two limitations 

in the 1997 retail sales data. First, the counted packages (units) varied in size and in concentration of active 

ingredients. Second, some active ingredients were not 

counted because only the first two active ingredients 

listed on a package were recorded into the database 

even though the product might contain several more 

active ingredients. One known instance is for the 

herbicide dicamba, which is listed as the third active 

ingredient in some products. However the number of

packages (units) sold do indicate consumer preference 

and thus is some indication of how widely the active 

ingredient is used in residential areas.

The rest of this report compares data in the 

pesticide retail sales database with pesticides detected 

in the stream-water samples collected for this study. 

The studied pesticides are grouped in the following 

categories:

 pesticides sold in retail stores and detected in 

stream-water samples,

 pesticides sold in retail stores but not detected,

 pesticides not sold in retail stores but detected,

 pesticides not sold in retail stores and not detected, 

and

 pesticides sold in retail stores but not sampled for.

Pesticides Sold in Retail Stores and 

Detected in Stream-Water Samples

Twelve pesticides detected in stream-water 

samples were sold in retail stores (table 5). High retail 

sales of several of these pesticides probably contribute 

to their being detected. This assumption was made 

because the pesticides 2,4-D, MCPP, and Diazinon 

(which had the highest unit sales of the pesticides 

sampled for) were detected at 100 percent of the 

sampling sites.

Table 5. Pesticides with retail sales and detected in streamwater samples, King and Snohomish Counties, Washington, 

1998

Pesticide

2,4-D

carbaryl

chlorpyrifos

Diazinon

dichlobenil

EPTC

Malathion

MCPA

MCPP

prometon

triclopyr

trifluralin

Units

sold,

1997

47,950

2,722

15,830

18,695

16,652

138

1,335

5,112

52,673

6,051

4,918

5,803

Percent

of sites

detected

100

67

8

100

100

16

33

73

100

100

91

25

12
MCPP

2,4-D

metaldehyde

iron sulfate

diquat dibromide

glyphosate

diazinon

dichlobenil

pyrethrins

chlorpyrifos

; permethrin

disulfoton

zinc

d-allethrin ^ m

tralomethrin LMMHMM 694(

prometon \mmmmmm 6051

trifluralin

triforine

MCPA

triclopyr

acephate

soap

tetramethrin

carbaryl

propoxur

piperonyl butoxide

arsenic trioxide

petroleum distillates

sodium metaborate

sodium chlorate 

sulfur 

propiconizole

sumithren 

malathion

hydramethylnon 

chlorothalonil

pendimethalin 

n-etfiy/perfluorooctane sulfon

phenothrin 

boric acid

cypermethrin

triadimefon

methoxychlor

thiram

iprodione

resmethrin

fenbutatin-oxide

captan

copper sulfate

bendiocarb

arsenic acid

B.T.

EPTC

methoprene

dimethoate

cyano

azadirachtin

MSMA

DGA

isoxaben

 5803

 5249

 5112

^^^ 4918

 4632

^^ 4359

 3815

^ 2722

 2152

 1832

 1700

**1652

 1633

 1633 

 n1584 

 11564

 1457 

 1335

 1303 

 1289

 1071 

 973

 711 

i533

i 420

i410

i 400

i 389

i337

i288

i 286

i274

1263

i258

i234

M99

138

114

84

69

62

54

39

15

J r\nr*r*

J t-nnn

 i 1 nQQi Uool

10245

9687

3695

2

1 AC i Ub

I

)50

EXPLANATION

Units of pesticide sold (unit)

 Pesticide detected in stream-water samples

"* * Pesticide not sampled for

^ Pesticide not detected in stream-water samples

0 10,000 20,000 30,000 40,000 50,000 60,000

Figure 7. Units of pesticide sold in 1997 at 10 home and garden stores located in western King and south 

Snohomish Counties (Market Trends, Incorporated, 1996).

13
Application of pesticides sold in retail outlets is a 

possible source of other frequently detected pesticides 

(such as dichlobenil and chlorpyrifos) that also have 

relatively high unit sales (fig. 8).

Relating pesticide concentrations found in 

stream water to the number of units of pesticides sold 

in home and garden stores was not attempted because 

tracking the many factors that influence pesticide distribution, degradation, and transport was beyond the 

scope of this study. Although this study did not determine how pesticides sold in home and garden stores are 

related to concentrations in urban streams, it is a starting point to determine which pesticides are found in 

urban streams and to determine whether the detected 

concentrations are exceeding aquatic-health criteria. 

It is hoped that this report will suggest ideas for further 

studies.

Pesticides Sold in Retail Stores but Not 

Detected in Stream-Water Samples

Five pesticides were sold in retail stores but were 

not detected in stream-water samples (table 6). They 

include two insecticides (permethrin, 15,377 units sold, 

and disulfoton, 12,030 units sold), two fungicides 

(chlorothalonil, 1,289 units sold, and triadimefon, 410 

units sold), and one herbicide (pendimethalin, 1,071 

units sold).

Table 6. Pesticides with retail sales and not detected in 

stream-water samples, King and Snohomish Counties, 

Washington, 1998

Pesticide Units sold, 1997

Permethrin 

Disulfoton 

Chlorothalonil 

Pendimethalin

Triadimefon

15,377

12,030

1,289

1,071

410

A plausible explanation for not detecting the 

insecticides is that they might not be widely distributed 

in the sampled watersheds. This is because insecticides 

tend to be applied to small areas of insect infestation,

whereas herbicides are believed to be combined with 

fertilizer and applied to entire lawns periodically 

through the growing season. The fungicides have 

lower sales than the insecticides and are also believed 

to be applied to problem areas.

Pesticides Not Sold in Retail Stores but 

Detected in Stream-Water Samples

Pesticides not sold in retail stores but detected in 

stream-water samples (table 7) probably originate 

from applications to nonresidential areas. Detected 

pesticides with a relatively small number of units sold 

(prometon, triclopyr, MCPA-see table 5) also may 

possibly be from nonresidential rather than residential 

applications.

Table 7. Pesticides with no retail sales but detected in 

stream-water samples, King and Snohomish Counties, 

Washington, 1998

Pesticide Percent of sites detected

Acetochlor

Atrazine

Dicamba

Dichlorprop

gamma-HCH (Lindane)

Metolachlor

Napropamide

Oxadiazon

Pentachlorophenol

Simazine

Tebuthiuron

67

36

27

25

25

16

9

100

67

It should be noted that detections of pesticides 

with little or no reported retail sales could still result, in 

part, from residential sales if one or more active ingredients mixed in the formulation were not reported. For 

example, dicamba, detected at nearly 40 percent of the 

study sites, is the third active ingredient listed in some 

combined fertilizer-pesticide products sold in home 

and garden stores. Also, pentachlorophenol was not 

shown in the database as being sold in retail stores, but 

it was detected in all the basins. It is a popular wood 

preservative.

14
Class Active 

ingredient

2,4-D

Dichlobenil 

MCPP 

Prometon 

Triclopyr 

MCPA 

Atrazine 

 £3 Simazine

 ^ Dicamba

_Q

J5 Dichlorprop 

1 Metolachlor 

Trifluralin 

EPTC 

Napropamide 

Oxadiazon 

Acetochlor 

Tebuthiuron 

Pendimethalin

Diazinon 

 <Q Carbaryl 

 Q Malathion

"o fifamma-HCH 

w Chlorpyrifos 

~ Disulfoton 

c/s-Permethrin

o> Pentachlorophenol 

'o Chlorothalonil 

c* Triadimefon

 I Use of trade names is for descrip 

*-* does not imply endorsement by 1 Survey, the Department of Ecolo

Trade name 

example

Weedone 

Casoron 

Mecoprop 

Pramitol 

Garlon 

Kilsem 

AAtrex 

Princep 

Banvel 

2,4-DP 

Dual 

Treflan 

Eptam 

Devrinol 

Ronstar 

Guardian 

Spike 

Prowl

Diazinon 

Sevin 

Malathion 

Lindane 

Dursban 

Di-syston 

Ambush

Penta 

Bravo 

Bayleton

live purposes and f 

he U.S. Geological 

gy, or King County

m Percentage of unit retail sales within a class (herbicide, 

insecticide, or fungicide) contributed by the pesticide

 Percentage of sites where pesticide was detected 

MS No sales reported from retail outlets 

ND Not detected at sites

^

 i

73

ia

NS

NS

" 

NS

MS 

MS

ND 

~^m

Q

MC

-_7^_ 

ND 

NS

mi

~

|

j

ND

1 ND

) 20 40 60 80 100 

PERCENT

1 Unit retail sales for these herbicides total to 140,000 units

2 Unit retail sales for these insecticides total to 66,000 units

3 Unit retail sales for these fungicides total to 1 ,700 units

Figure 8. Comparisons of units of pesticides sold with the percentage of study watersheds where 

pesticide detections occurred, King and Snohomish Counties, Washington, 1998.

15
Pesticides Not Sold in Retail Stores and 

Not Detected in Stream-Water Samples

Sixty-six pesticides sampled for but not sold in 

retail stores were not detected (table 8). For the most 

part, the fact that these pesticides were not sold or 

detected indicates little usage in urban watersheds. 

This conclusion is consistent with findings based on 

samples from 58 rivers and streams across the United

Table 8. Pesticides with no retail sales and not detected in 

stream-water samples, King and Snohomish Counties, 

Washington, 1998

Pesticides

2.3.4.5-tetrachlorophenol

2.3.4.6-tetrachlorophenol

2,4,5-T

2,4,5-TB

2,4,5-TP

2.4.5-trichlorophenol

2.4.6-trichlorophenol

2,4-DB

3,5-dichlorobenzoic acid

Acifluorfen

Alachlor

Alpha-HCH

Ametryn

Atraton

Azinphos-methyl

Benfluralin

Bentazon

Bromacil

Bromoxynil

Butachlor

Butylate

Carbofuran

Carboxin

Chlorpropham

Cyanazine

Cycloate

DCPA

Diallate

Diclofop-methyl

Dieldrin

Dinoseb

Diphenamid

Diuron

Ethalfluralin

Ethoprophos

Fenarimol

Fluridone

Fonofos

Hexazinone

loxynil

Linuron

Metalaxyl

Metribuzin

MGK264

Molinate

Norflurazon

Oxyfluorfen

p,p'-DDE

Parathion

Parathion-methyl

Pebulate

Phorate

Picloram

Profluralin

Prometryn

Propachlor

Propanil

Propargite

Propazine

Propyzamide

Terbacil

Terbufos

Terbutryn

Thiobencarb

Triallate

Vernolate

States (Larson and others, 1996). Several of the pesticides not detected in samples collected during this 

study were either not detected or detected infrequently 

in samples from urban streams across the United 

States. Examples are the herbicides terbacil and 

triallate and the insecticides azinphos-methyl and 

carbofuran.

Pesticides Sold in Retail Stores 

but Not Assessed

Sixty-one active ingredients were listed as sold 

in retail home and garden stores. Seventeen of the 61 

were sampled for, leaving 44 pesticides (table 9) sold in 

retail stores but not sampled for.

Pesticides routinely analyzed at the USGS 

NWQL were selected because they are most frequently 

sold in the United States and are fairly easy to extract 

(Gilliom and others, 1995). Thus, there was a gap 

between what was sold and what was sampled for.

Some of the sales of the pesticides not sampled 

were relatively large. For example, 44,538 units of 

metaldehyde and 26,323 units of glyphosate were sold. 

Pesticides that were sold in equivalent numbers 

(52,673 units of MCPP and 47,950 of 2,4-D) and 

sampled for were found in all of the sample sites 

(except the reference site).

IMPLICATIONS OF THIS STUDY FOR 

FUTURE RESEARCH

This study is valuable as an exploratory study for 

future work in measuring pesticide concentrations in 

surface water and has many implications for further 

research. A weak relation was found between pesticide 

sales and some pesticide concentrations in stream 

water. This does not necessarily imply that pesticides 

are not being washed into the surface water. In fact, 

there are many intervening variables that could contribute to these weak relations, and these variables need 

further study before any definitive conclusions can 

be drawn.

In this study, it was assumed that most pesticides 

were purchased in the spring for immediate use. This 

might not necessarily be the case. Pesticides might be 

purchased in the spring for use throughout the spring 

and summer. If this is the case, sampling of surface 

water in the spring might measure only initial applications. It would therefore be interesting to study the

16
Table 9. Pesticides and other compounds with retail sales that were not sampled for, King and Snohomish Counties, 

Washington, 1998

Pesticide Units sold, 1997 Pesticide Units sold, 1997

Acephate

Arsenic Acid

Arsenic trioxide

Azadirachtin

B.T.

Bendiocarb

Boric Acid

Captan

Copper sulfate

Cyano

Cypermethrin

D-allethrin

DGA

Dimethoate

Diquat dibromide

Fenbutatin-oxide

Fluazifop

Glyphosate

Hydramethylnon

Iprodione

Iron sulfate

Isoxaben

4,632

234

1,700

62

199

258

533

274

263

69

420

9,687

39

84

28,106

286

10,245

26,323

1,303

337

43,905

15

Metaldehyde

Methoprene

Methoxychlor

MSMA

N-ethyl perfluorooctane sulfon

Petroleum distillates

Phenothrin

Piperonyl butoxide

Propiconizole

Propoxur

Pyrethrins

Resmethrin

Soap

Sodium chlorate

Sodium metaborate

Sulfur

Sumithren

Tetramethrin

Thiram

Tralomethrin

Triforine

Zinc

44,538

114

400

54

973

1,652

711

1,832

1,564

2,152

16,069

288

4,359

1,633

1,633

1,584

1,457

3,815

389

6,940

5,249

10,831

concentrations of pesticides in surface water throughout the spring and summer to determine if any relations 

could be found.

This study serves as a general survey of pesticide 

concentrations during a limited time frame. However, 

not all pesticides are the same-they have different 

properties. Some pesticides are transformed faster in 

the environment than others. Pesticides also have different transport times and different solubilities in water. 

Again, a study that encompasses a larger time frame 

and that measures and analyzes each pesticide concentration within the context of its unique properties (such 

as transformation time, transformation products, and 

transport time) would be useful.

Future studies relating sales data to pesticide 

concentrations might also benefit from standardizing 

and quantifying unit sales, such as pounds of active 

ingredients. Unfortunately, for this study, unit sales 

could not be broken down into quantifiable units that 

could be compared across pesticides or meaningfully

compared to pesticide concentrations found in surface 

water. Ranking pesticides by their toxicity to aquatic 

life would also help assess the relative environmental 

impact of pesticides. Future studies could focus on 

these problems in the data-collection phase.

SUMMARY

In Spring 1998, the U.S. Geological Survey and 

the Washington State Department of Ecology cooperated in sampling 13 sites in 11 watersheds during 

storms, when more pesticides and higher concentrations might be detected than at any other time of 

the year.

Ninety-eight pesticides and pesticide transformation products were sampled for at each site. The 

USGS used the 2010 laboratory schedule, and Ecology 

used the chlorinated herbicide and nitrogen-containing 

laboratory schedules.

17
Twenty-six of the 98 pesticides and pesticide 

transformation products were detected-23 pesticides 

(17 herbicides, 5 insecticides, and 1 fungicide) and 

3 transformation products. The herbicides dichlobenil, 

2,4-D, MCPP, the insecticide Diazinon, and the fungicide pentachlorophenol were detected at all of the 

urban study sites.

Five insecticides-carbaryl, chlorpyrifos, 

Diazinon, Lindane, and Malathion exceeded maximum 

concentration limits for the protection of aquatic life 

established by the National Academy of Sciences and 

National Academy of Engineering (NAS/NAE) or the 

Ministers of Health Canada and Environment Canada. 

Lindane, Diazinon, and carbaryl exceeded chronic 

aquatic-life criteria recommended by Norris and Dost, 

the U.S. Environmental Protection Agency, and others.

Sales data for 61 pesticides were obtained from 

10 home and garden stores located in urban and suburban areas in King and south Snohomish Counties. 

Estimating the amounts of pesticides applied in watersheds was not possible because of two limitations in the 

1997 retail sales data. First, the counted packages 

(units) varied in size and in concentration of active 

ingredient. Second, some active ingredients were not 

counted. However, the number of packages (units) sold 

did indicate consumer preference and thus is some 

indication of how widely the active ingredient is used 

in residential areas.

Twelve pesticides detected in stream-water 

samples were sold in retail stores. High retail sales of 

2,4-D, MCPP, and Diazinon probably contributed to 

their being detected at 100 percent of the sampling 

sites. Application of pesticides sold in retail outlets 

was a possible source of other frequently detected 

pesticides (such as dichlobenil and chlorpyrifos) that 

also have relatively high unit sales.

Five pesticides sold in retail stores were not 

detected in stream-water samples-two insecticides 

(m-permethrin and disulfoton), two fungicides 

(chlorothalonil and triadimefon), and one herbicide 

(pendimethalin). Possibly they were not detected 

because some of them are relatively insoluble in water 

and are not likely to be transported in runoff. Alternately, some of them might not be widely distributed in 

the sampled watersheds.

Pesticides not sold in retail stores but detected in 

stream-water samples probably originate from applications to nonresidential areas. Detected pesticides with 

a small number of units sold (prometon, triclopyr,

MCPA) also may be from nonresidential rather than 

residential applications.

This study is valuable as an exploratory study for 

future work in measuring pesticide concentrations in 

surface water and has many implications for further 

research. A weak relation was found between pesticide 

sales and some pesticide concentrations in stream 

water. This does not necessarily imply that pesticides 

are not being washed into the surface waters. In fact, 

there are many intervening variables that could contribute to these weak relations, and these variables must 

further be studied before any definitive conclusions can 

be drawn.

REFERENCES CITED

Anderson, J.R., Hardy, E.E., and Witmer, R.E., 1976, A land 

use and cover classification system for use with remote 

sensor data: U.S. Geological Survey Professional Paper 

964,27p.

Beautiful Seattle.com, Seattle Weather: accessed September, 1999, at http://beautifulseattle.com/weasea.htm

Davis, D.A., 1998, Washington State pesticide monitoring 

program, 1996 surface water sampling report: Washington Department of Ecology Publication No. 98-305, 

16 p.

 2000, Washington State pesticide monitoring 

program, 1997, surface water sampling report: 

Washington Department of Ecology Publication 

No. 00-03-003, 19 p.

Edwards, T.K., and Glysson, G.D., 1988, Field methods for 

measurement of fluvial sediment: U.S. Geological 

Survey Open-File Report 86-531, 118 p.

Gilliom, R.J., Alley, W.M., and Gurtz, M.E., 1995, Design of 

the National Water-Quality Assessment ProgramOccurrence and distribution of water-quality conditions: U.S. Geological Survey Circular 1112, 33 p.

Hitt, K.J., 1995, Refining 1970's land-use data with 1990 

population data to indicate new residential development: U.S. Geological Survey Water-Resources 

Investigations Report 94-4250, 15 p.

Larson, S.J., Capel, P.D., and Majewski, M.S., 1996, Pesticides in surface waters-Distribution, trends, and governing factors: Chelsea, Mich., Ann Arbor Press, 

Pesticides in Hydrologic System Series, v. 3, 373 p.

Market Trends Incorporated, 1996, 1996 King County 

household hazardous waste survey report: Bellevue, 

Wash., prepared for King County Local Hazardous 

Waste Management Program, 74 p.

18
Menconi, M., and Cox, C., 1994, Hazard assessment of the 

insecticide diazinon to aquatic organisms in the Sacramento-San Joaquin River System: California Department of Fish and Game, Environmental Services 

Division, Administrative Report 94-2, 60 p.

Ministers of Health Canada and Environment Canada, 1995, 

Canadian water guidelines-summary of guidelines for 

water quality in Canada: Ottawa, Ontario, Canada, 

Minister of Supply and Services Canada, 7 p.

National Academy of Sciences and National Academy of 

Engineering, 1973, Water quality criteria, 1972, a 

report of the committee on water quality criteria: 

Washington, D.C., Environmental Studies Board, 

National Academy of Sciences, National Academy 

of Engineering, 594 p.

Norris, L., and Dost, F., 1991, Proposed surface water 

quality criteria for selected pesticides used for forest 

management and management of forest tree seedling 

and Christmas tree plantations in Oregon and Washington (draft): Corvallis, Oreg., Oregon State University, 

39 p.

Sandstrom, M.W., Wydoski, D.S., Schroeder, M.P.,

Zamboni, J.L., and Foreman, W.T., 1992, Methods of 

analysis by the National Water Quality LaboratoryDetermination of organonitrogen herbicides in water by 

solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion 

monitoring: U.S. Geological Survey Open-file Report 

91-519, 26 p.

Shelton, L.R., 1994, Field guide for collecting and processing stream-water samples for the National WaterQuality Assessment Program: U.S. Geological Survey 

Open-File Report 94-455, 42 p.

State of Washington, 1992, Water quality standards for 

surface waters in the State of Washington: Olympia, 

Wash., State of Washington, Chapter 173-201 WAC, 

14 p.

U.S. Environmental Protection Agency, 1998, Quality criteria for water: Washington, D.C., U.S. Environmental 

Protection Agency, Office of Regulations and 

Standards, unpaginated.

Wagner, R.J., Ebbert, J.C., Roberts, L.M., and Ryker, S.J., 

1996, Agricultural pesticide applications and observed 

concentrations in surface waters from four drainage 

basins in the Central Columbia Plateau, Washington 

and Idaho, 1993-94: U.S. Geological Survey WaterResources Investigations Report 95-4285, 52 p.

Zaugg, S.D., Sandstrom, M.W, Smith, S.G., and Fehlberg, 

K.M., 1995, Methods of analysis by the U.S. Geological Survey National Water Quality LaboratoryDetermination of pesticides in water by C-18 solidphase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring: U.S. Geological Survey Open-File Report 95-181, 

49 p.

19
APPENDICES
Appendix A. Pesticides analyzed by the USGS in this study and their method detection limits 

[Abbreviations: H, herbicide; I, insecticide; (ig/L, microgram per liter]

Chemical 

Abstract 

Service (CAS) 

identification 

number

579-66-8

34256-82-1

15972-60-8

319-84-6

1912-24-9

86-50-0

1861-40-1

2008-41-5

63-25-2

1563-66-2

2921-88-2

21725-46-2

1861-32-1

6190-65-4

333-41-5

60-57-1

298-04-4

759-94-4

55283-68-6

13194-48-4

944-22-9

58-89-9

330-55-2

121-75-5

51218-45-2

21087-64-9

2212-67-1

15299-99-7

56-38-2

298-00-0

1114-71-2

40487-42-1

5264-55-3

298-02-2

72-55-9

1610-18-0

1918-16-7

709-98-8

2312-35-8

23950-58-5

122-34-9

34014-18-1

5902-51-2

13071-79-9

28249-77-6

2303-17-5

1582-09-8

Pesticide 

name

2,6-Diethylaniline*

Acetochlor

Alachlor

alpha-HCH

Atrazine

Azinphos-methyl

Benfluralin

Butylate

Carbaryl

Carbofuran

Chlorpyrifos

Cyanazine

DCPA

Desethylatrazine*

Diazinon

Dieldrin

Disulfoton

EPIC

Ethalfluralin

Ethoprophos

Fonofos

Lindane

Linuron

Malathion

Metolachlor

Metribuzin

Molinate

Napropamide

Parathion

Parathion-methyl

Pebulate

Pendimethalin

tw-permethrin

Phorate

p,p'-DDE

Prometon

Propachlor

Propanil

Propargite

Propyzamide

Simazine

Tebuthiuron

Terbacil

Terbufos

Thiobencarb

Triallate

Trifluralin

Pesticide 

type

H

H

H

I

H

I

H

H

I

I

I

H

H

H

I

I

I

H

H

I

I

I

H

I

H

H

H

H

I

I

H

H

I

I

I

H

H

H

I

H

H

H

H

I

H

H

H

Method 

detection 

limit 

(^g/L)

0.003

0.002

0.002

0.002

0.001

0.001

0.002

0.002

0.003

0.003

0.004

0.004

0.002

0.002

0.002

0.001

0.017

0.002

0.004

0.003

0.003

0.004

0.002

0.005

0.002

0.004

0.004

0.003

0.004

0.006

0.004

0.004

0.005

0.002

0.006

0.018

0.007

0.004

0.013

0.003

0.005

0.01

0.007

0.013

0.002

0.001

0.002

* Pesticide transformation product.

21
Appendix B. Nitrogen-containing pesticides analyzed 

by the Washington State Department of Ecology in this 

study and their quantitation limits 

[|Ig/L, micrograms per liter]

Appendix C. Chlorinated herbicides analyzed for by 

the Washington State Department of Ecology in this 

study and their quantitation limits 

[|ig/L, micrograms per liter]

Chemical 

Abstract 

Service (CAS) 

identification 

number

15972608

834128

1610179

1912249

1861401

2008584

314409

23184669

2008415

5234684

1897456

101213

21725462

1134232

2303164

1194656

957517

330541

759944

55283686

60168889

59756604

51235042

57837191

51218452

21087649

113484

2212671

15299997

27314132

19666309

42874033

1114712

40487421

26399360

1610180

7287196

23950585

1918167

139402

122349

34014181

5902512

886500

43121433

2303175

1582098

1929777

Analyte

Alachlor

Ametryn

Atraton

Atrazine

Benefin

Benzamide, 2,6-dichloroBromacil

Butachlor

Butylate

Carboxin

Chlorothalonil

Chlorpropham

Cyanazine

Cycloate

Diallate

Dichlobenil

Diphenamid

Diuron

EPIC

Ethalfluralin

Fenarimol

Fluridone

Hexazinone

Metalaxyl

Metolachlor

Metribuzin

MGK264

Molinate

Napropamide

Norflurazon

Oxadiazon

Oxyfluorfen

Pebulate

Pendimethalin

Profluralin

Prometon

Prometryn

Pronamide

Propachlor

Propazine

Simazine

Tebuthiuron

Terbacil

Terbutryn

Triadimefon

Triallate

Trifluralin

Vernolate

Quantitation 

limit !

ow

0.26

0.071

0.21

0.071

0.11

0.081

0.28

0.25

0.14

0.78

0.17

0.028

0.11

0.14

0.27

0.16

0.21

0.48

0.14

0.11

0.21

0.43

0.11

0.48

0.28

0.071

0.50

0.14

0.21

0.14

0.04

0.28

0.14

0.11

0.17

0.071

0.071

0.28

0.17

0.071

0.072

0.11

0.21

0.071

0.18

0.18

0.11

0.14

1 Quantitation limits are approximate and are often 

different for each sample; these values are representative 

of a typical sample.

22

Chemical 

Abstract 

Service (CAS) 

identification 

number

4901513

58902

93765

93801

93721

95954

88062

94757

94826

51365

100027

62476599

25057890

1689845

1861321

1918009

120365

51338273

88857

1689834

94746

93652

87865

1918021

55335063

Analyte

2,3 ,4,5-Tetrachlorophenol

2,3 ,4,6-Tetrachlorophenol

2,4,5-T

2,4,5-TB

2,4,5-TP (Silvex)

2,4,5-Trichlorophenol

2,4,6-Trichlorophenol

2,4-D

2,4-DB

3,5-Dichlorobenzoic Acid

4-Nitrophenol

Acifluorfen (Blazer)

Bentazon

Bromoxynil

DCPA

Dicamba

Dichlorprop

Diclofop-methyl

Dinoseb

loxynil

MCPA

MCPP

Pentachlorophenol

Picloram

Trichlopyr

Quantitation 

limit l 

(Hg/L)

0.023

0.023

0.033

0.038

0.033

0.025

0.025

0.042

0.050

0.042

0.073

0.17

0.063

0.042

0.033

0.042

0.046

0.063

0.063

0.042

0.083

0.083

0.021

0.042

0.035

1 Quantitation limits are approximate and are often 

different for each sample; these values are representative 

of a typical sample.

£ U.S. GOVERNMENT PRINTING OFFICE: 2000 589-438 / 03025 Region No. 10
ZUSGS Voss, F.D. and S.S. Emorey^ PESTICIDES DETECTED IN URBAN STREAMS DURING RAINSTORMS IN KING 

AND SNOHOMISH COUNTIES, WASHINGTON, 1998