Water Quality in the

Puget Sound Basin

Washington and British Columbia, 1996–98

U.S. Department of the Interior

U.S. Geological Survey

Circular 1216
POINTS OF CONTACT AND ADDITIONAL INFORMATION

Front cover: The Port of Tacoma in foreground looking up the Puyallup River Valley toward Mount Rainier in the 

background. (Photograph © by Kemer Nelson, Aequalis Aerial Photography, Tacoma, Washington. Used with 

permission.)

Back cover: The Port of Tacoma in foreground looking northwest toward the Olympic Mountains. (Photograph © by 

Kemer Nelson, Aequalis Aerial Photography, Tacoma, Washington. Used with permission.)

The companion Web site for NAWQA summary reports:

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

Puget Sound Basin contact and Web site:

USGS State Representative

U.S. Geological Survey

Water Resources Division

1201 Pacific Avenue

Suite 600

Tacoma, WA 98402

e-mail: gs-w_nawqa_pugt_ch@usgs.gov

http://wa.water.usgs.gov/ps.nawqa.html

National NAWQA Program:

Chief, NAWQA Program

U.S. Geological Survey

Water Resources Division

12201 Sunrise Valley Drive, M.S. 413

Reston, VA 20192

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

River Basin Assessments

Albemarle-Pamlico Drainage Basin (Circular 1157)

Allegheny and Monongahela River Basins (Circular 1202)

Apalachicola-Chattahoochee-Flint River Basin (Circular 1164)

Central Arizona Basins (Circular 1213)

Central Columbia Plateau (Circular 1144)

Central Nebraska Basins (Circular 1163)

Connecticut, Housatonic and Thames River Basins (Circular 1155)

Eastern Iowa Basins (Circular 1210)

Georgia-Florida Coastal Plain (Circular 1151)

Hudson River Basin (Circular 1165)

Kanawha - New River Basins (Circular 1204)

Lake Erie - Lake Saint Clair Drainages (Circular 1203)

Las Vegas Valley Area and the Carson and Truckee River Basins

(Circular 1170)

Lower Illinois River Basin (Circular 1209)

Long Island - New Jersey Coastal Drainages (Circular 1201)

Lower Susquehanna River Basin (Circular 1168)

Mississippi Embayment (Circular 1208)

Ozark Plateaus (Circular 1158)

Potomac River Basin (Circular 1166)

Other NAWQA summary reports

Red River of the North Basin (Circular 1169)

Rio Grande Valley (Circular 1162)

Sacramento River Basin (Circular 1215)

San Joaquin-Tulare Basins (Circular 1159)

Santee River Basin and Coastal Drainages (Circular 1206)

South-Central Texas (Circular 1212) 

South Platte River Basin (Circular 1167)

Southern Florida (Circular 1207)

Trinity River Basin (Circular 1171)

Upper Colorado River Basin (Circular 1214) 

Upper Mississippi River Basin (Circular 1211)

Upper Snake River Basin (Circular 1160)

Upper Tennessee River Basin (Circular 1205)

Western Lake Michigan Drainages (Circular 1156)

White River Basin (Circular 1150)

Willamette Basin (Circular 1161)

National Assessments

The Quality of Our Nation’s Waters—Nutrients and Pesticides

(Circular 1225)
U.S. GEOLOGICAL SURVEY CIRCULAR

Water Quality in the Puget Sound Basin,

Washington and British Columbia, 1996–98

1216

By James C. Ebbert, Sandra S. Embrey, Robert W. Black, Anthony J. Tesoriero,

and Alan L. Haggland
Library of Congress Cataloging-in-Publications Data

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

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

Free on application to the

U.S. Geological Survey

Information Services

Box 25286 Federal Center

Denver, CO 80225

Or call: 1-888-ASK-USGS

U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

2000

Water-quality assessment of the Puget Sound basin, Washington and British Columbia, 1996–98 / by James C. 

Ebbert...[et al.].

p. cm. -- (U.S. Geological Survey Circular ; 1216)

Includes bibliographical references.

ISBN 0-607-95420-5 (alk. paper)

1. Water quality--Washington (State)--Puget Sound Region. 2. Water quality--British Columbia. I. Ebbert, 

J. C. II. Series.

TD224.C3 W394 2000

363.739’42’097977--dc21

00-049456
CONTENTS

Contents III

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

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

Stream and river highlights........................................................................................................................... 1

Ground-water highlights ............................................................................................................................... 2

INTRODUCTION TO THE PUGET SOUND BASIN ........................................................................................... 3

Land use affects water quality and stream habitat ....................................................................................... 3

Water availability is a major issue................................................................................................................. 4

Hydrologic conditions probably affected study results.................................................................................. 5

Some ground water is susceptible to contamination .................................................................................... 5

Study design focuses on land use................................................................................................................ 5

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

Pesticides in surface water were indicative of upstream land uses, and more pesticides were

detected in streams than in rivers ............................................................................................................. 6

NATIONAL PERSPECTIVE—Insecticides in Thornton Creek were also detected in urban streams 

throughout the Nation................................................................................................................................ 8

Historically used pesticides and PCBs are still detected in streambed sediments and fish tissue............... 8

Streams and rivers in developed areas were enriched with nutrients relative to those 

in undeveloped areas ................................................................................................................................ 11

Runoff during rainstorms contributes contaminants to streams, indicating nonpoint sources...................... 12

Bacteria indicate the presence of fecal contamination in many Puget Lowland streams ............................. 13

Stream habitat and health are degraded in agricultural and urban streams................................................. 13

NATIONAL PERSPECTIVE—Puget Sound stream invertebrate status ranged from high to low 

when compared with national levels.......................................................................................................... 15

Ground-water quality is generally good ........................................................................................................ 16

Nitrate concentrations in shallow ground water beneath residential areas were elevated, but 

concentrations of other compounds were low ........................................................................................... 17

High nitrate concentrations and fumigant-related compounds were detected in shallow ground water 

beneath an agricultural area...................................................................................................................... 18

NATIONAL PERSPECTIVE—MTBE was rarely detected in ground water in the Puget Sound Basin......... 19

STUDY UNIT DESIGN ........................................................................................................................................ 20

GLOSSARY ........................................................................................................................................................ 22

REFERENCES.................................................................................................................................................... 24

APPENDIX—WATER-QUALITY DATA FROM THE PUGET SOUND BASIN IN A NATIONAL CONTEXT ........ 26
NATIONAL WATER-QUALITY ASSESSMENT PROGRAM

IV National Water-Quality Assessment Program 

THIS REPORT summarizes major findings about water quality in the Puget Sound Basin that emerged from an 

assessment conducted between 1996 and 1998 by the U.S. Geological Survey (USGS) National Water-Quality 

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

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

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

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

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

complementing many ongoing Federal, State, and local drinking-water monitoring programs. The comparisons 

made in this report to drinking-water standards and guidelines are only in the context of the available untreated 

resource. Finally, this report includes information about the status of aquatic communities and the condition of 

in-stream habitats as elements of a complete water-quality assessment.

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

managers, and members of stakeholder groups who provided advice and input during the Puget Sound River Basin 

assessment. Basin residents who wish to know more about water quality in the areas where they live will find this 

report informative as well. 

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

major river basins and ground-water systems. Better understanding facilitates effective resource management, 

accurate identification of water-quality priorities, and successful development of strategies that protect and restore 

water quality. Guided by a nationally consistent study design and shaped by ongoing communication with local, 

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

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

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

The Puget Sound Basin is one of 51 water-quality assessments initiated since 1991, when the U.S. Congress 

appropriated funds for the USGS to begin the NAWQA Program. As indicated on the map, 36 assessments have 

been completed, and 15 more assessments will conclude in 2001. Collectively, these assessments cover about 

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

of the U.S. population.

Not yet scheduled

NAWQA Study Units±

Assessment schedule

Puget Sound Basin

1991 95

1994 98

1997 2001

High Plains Regional

Ground Water Study,

1999 2004
Summary of Major Findings 1 

SUMMARY OF MAJOR FINDINGS 

Stream and River Highlights

Streams and rivers in the Puget Sound Basin met 

most Federal and State water-quality guidelines. In 

general, large rivers were more likely to meet guidelines than were small streams. Concentrations of 

fecal bacteria frequently exceeded U.S. Environmental Protection Agency (USEPA) recreational 

criteria and State standards protecting beneficial 

uses of surface water, and insecticide concentrations 

were occasionally higher than guidelines recommended to protect aquatic life. A total of 74 manmade organic chemicals were detected in streams 

and rivers, with different mixtures of chemicals 

linked to agricultural and urban settings. Though 

most chemical concentrations appeared to be low, 

guidelines for drinking water and aquatic life that 

The Puget Sound Basin is a 13,700-square-mile area of 

mountains and coastal lowlands in western Washington 

State and portions of British Columbia. About 4 million 

people live in the basin, mainly in metropolitan areas of 

Seattle, Tacoma, Everett, Bellingham, and Olympia. 

Headwaters of major rivers provide much of the drinking 

water for these metropolitan areas. Ground water is the 

primary source of drinking water in rural areas and, 

increasingly, for new suburbs.

Nooksack Rive r

Skagit

Ri ver

Still a guamish Riv er

Sno homish

River

Gree n River

Puyall up

R i ver

Nisqual ly

Ri ver

Skokomis h River

El w h a

River

PUGET

SOUND

Bellingham

Everett

Seattle

Tacoma

Olympia

Cascade

Range

Oly

mpic

Mountains

 BRITISH 

COLUMBIA

CANADA

UNITED STATES

INTERNATIONAL

 BOUNDARY

49°

47°

EXPLANATION

123°

121°

LAND-USE TYPE

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

AGRICULTURAL

OTHER

URBAN

FOREST

are needed to make a full assessment do not exist 

for more than half the compounds detected.

• The insecticide diazinon, commonly used by homeowners on lawns and gardens, was frequently 

detected in urban streams at concentrations that 

exceeded guidelines for protecting aquatic life (p. 6).

• The average concentration of total nitrogen in small 

streams draining agricultural lands was twice the 

concentration in streams draining urban areas and 

over 40 times the concentration in streams draining 

undeveloped areas. Concentrations of total phosphorus were less dependent on land use, and concentrations above the USEPA desired goal of 0.1 mg/L to 

prevent excessive plant growth were detected in 

rivers and streams in all but undeveloped areas 

(p. 11).

• Concentrations of E. coli bacteria exceeded USEPA 

criteria for moderate water-contact recreation, 

including swimming, in 15 of 31 small streams. 

Livestock, pet, and wildlife wastes, and to some 

extent human sewage, are likely sources of these 

bacteria (p. 13).

__________________________________________ 1

 Insecticides, herbicides, and pesticide metabolites, sampled 

in water. 2

 Total phosphorus and nitrate (as nitrogen), sampled in water.

3

 Organochlorine compounds including DDT and PCBs, 

sampled in fish tissue. 4

 Miscellaneous industrial chemicals and combustion byproducts, sampled in sediment.

Urban Agricultural Undeveloped

and Forest

Mixed

Land Uses

Small Streams Major Rivers

Selected Indicators of Surface-Water Quality 

Pesticides1

Nutrients2

Organochlorines3

Semivolatile

organics4

—

Percentage of samples with concentrations equal to or

greater than a health-related national guideline for drinking

water or aquatic life; or above a national goal for preventing

excess algal growth

Percentage of samples with concentrations less than a

health-related national guideline for drinking water or aquatic

life; or below a national goal for preventing excess algal

growth 

Percentage of samples with no detection

Not assessed

—
2 Water Quality in the Puget Sound Basin

Major Influences on Ground Water

• Poultry and dairy waste 

• Lawn and garden fertilizers

• Septic systems

• Fumigants no longer in use

Major Influences on Streams and Rivers

• Contaminants in runoff from urban and 

agricultural land surfaces

• Degraded stream habitat in urban and 

agricultural areas

• Urban expansion into forested areas is changing 

stream habitats, in part because of changes in water 

quality. Streams in urban and agricultural areas are 

warmer and support less diverse populations of 

insects than those in forested areas (p. 14).

Trends in Surface-Water Quality

Concentrations of nitrate and phosphorus in 

the Nooksack and Green Rivers did not change 

between 1980 and 1997. During the same period, 

concentrations of nitrate in the Skokomish River 

and in Big Soos and Newaukum Creeks 

increased slightly (p. 12).

Ground-Water Highlights

Reliance on ground water as a source of drinking water is increasing with urban and suburban 

development. With some exceptions, ground 

water is of high quality. However, as indicated 

by elevated concentrations of nitrate and the 

presence of pesticides and other organic compounds, shallow ground water in both urban and 

agricultural settings is vulnerable to contamination. Monitoring wells in urban residential areas 

generally contained low-concentration mixtures 

of chemicals associated with transportation and 

household activities. Shallow ground water, at 

depths tapped for domestic supply in agricultural 

areas, contained fertilizer residues (nitrate) at 

concentrations that commonly exceeded the 

drinking-water standard. Other agricultural 

chemicals were also frequently detected, though 

mostly at concentrations below current Federal 

and State drinking-water guidelines.

• Use of fertilizers on urban lawns and gardens and 

drainage from septic systems have elevated nitrate 

concentrations in shallow ground water beneath 

urban residential areas. In most samples, these 

concentrations were substantially less than the 

drinking-water standard (p. 17).

• Pesticides were not detected in wells that are more 

than 120 feet deep, the depth below which most 

large public-supply wells withdraw water. 

Pesticides were detected in wells that are less than 

100 feet deep, the range of many rural and suburban 

domestic wells, but concentrations met drinkingwater guidelines. Only about half of the detected 

pesticides have guidelines, and no benchmarks 

are available to assess the significance of lowconcentration mixtures of pesticides (p. 16).

• Applications of fertilizers and dairy and poultry 

manure to cropland in agricultural areas of the 

Nooksack River Basin have increased nitrate 

concentrations above the USEPA drinking-water 

standard in about 60 percent of the shallow ground 

water sampled (p. 18).

• Prior to 1977, 1,2-dichloropropane was one of the 

ingredients in fumigants used on potatoes and 

berries in the Nooksack River Basin. Currently 

used fumigants contain only trace amounts of this 

compound, and their application is not likely contaminating ground water to concentrations exceeding drinking-water standards (p. 19).

Selected Indicators of Ground-Water Quality

Shallow Ground Water Supply Wells

Urban Domestic Public Agricultural

Nitrate

Pesticides

Radon

Volatile

organics1

—

Percentage of samples with concentrations equal to or greater

than a health-related national guideline for drinking water

Percentage of samples with concentrations less than a healthrelated national guideline for drinking water

Percentage of samples with no detection

Not assessed

1 Solvents, refrigerants, fumigants, and gasoline compounds, sampled in water.

—

—

—

—

—
Introduction to the Puget Sound Basin 3 

INTRODUCTION TO THE PUGET SOUND BASIN

KITSAP

PIERCE

 SAN 

JUAN

ISLAND

WHATCOM

SKAGIT

SNOHOMISH CLALLAM

JEFFERSON

KING

LEWIS

THURSTON

MASON

BRITISH COLUMBIA

CANADA

UNITED STATES

Olympic

Mountains

Cascade

Range

Puget

Lowlands

Bellingham

Everett

Seattle

Tacoma

Olympia

INTERNATIONAL BOUNDARY

COUNTY BOUNDARY

EXPLANATION

PHYSIOGRAPHIC PROVINCE BOUNDARY

Rivers in forested headwaters

supply most of the drinking water

for major urban centers.

(Photograph by Bob Black,

U.S. Geological Survey.)

Streambank vegetation is sparse along

an agricultural stream. (Photograph by

Bob Black, U.S. Geological Survey.)

Urban land use is concentrated in the

Puget Lowlands. (Photograph by Ward

Staubitz, U.S. Geological Survey.)

49°

47°

123°

121°

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

The Puget Sound Basin encompasses the 13,700-square-mile area 

that drains to Puget Sound and 

adjacent marine waters. Included 

are all or part of 13 counties in 

western Washington, as well as the 

headwaters of the Skagit River and 

part of the Nooksack River in British Columbia, Canada. Streams 

and rivers drain three physiographic provinces—the Olympic 

Mountains in the west, the 

Cascade Range in the east, and the 

Puget Lowlands in the center

of the basin (fig. 1).

Land Use Affects Water

Quality and Stream Habitat

Nearly 4 million people, or 

about 70 percent of Washington 

State’s population, live in the 

Puget Sound Basin. Urban growth 

is rapid; by 2020, the population is 

expected to increase 

by 1.1 million people, 

with most growth in 

urban and suburban 

areas. Urban and 

agricultural land uses, 

which cover about 

9 and 6 percent of 

the basin, respectively (fig. 2), are 

concentrated in the 

lowlands. Forest 

dominates land use 

and cover in the basin 

and is concentrated 

in the foothills and 

mountains (see map, p. 1).

The quality of water and aquatic 

biota has been affected by a range 

of forestry, agricultural, and urban 

development practices. The 

chemical quality of surface water 

in the foothills and mountains is 

generally suitable for most uses. 

However, the physical hydrology, 

water temperature, and biologic 

integrity of streams have been 

influenced to varying degrees by 

logging (Black and Silkey, 1998). 

Figure 1. Streams and rivers drain three physiographic provinces in the Puget Sound Basin (Black and Silkey, 1998).

0

2,000

4,000

6,000

8,000

10,000

12,000

0

10

20

30

40

50

60

70

80

FOREST URBAN AND BUILTUP LANDAGRICULTURAL LAND OTHER

Total area = 13,700 square miles

AREA, IN SQARE MILES

PERCENTAGE OF TOTAL AREA

Figure 2. Land use and cover in the basin is 

predominantly forest.
4 Water Quality in the Puget Sound Basin

The quality of ground water in the 

upper watersheds probably differs 

little from natural conditions.

Because of development, many 

streams in the Puget Lowlands 

have undergone changes in structure and function with a trend 

toward simplification of stream 

channels and loss of habitat 

(Black and Silkey, 1998). Sources 

of contaminants to lowland 

streams and lower reaches of 

large rivers are largely nonpoint 

because most major point sources 

discharge directly to Puget Sound. 

Compared with that in small 

streams in the Puget Lowlands, 

the quality of water in the lower 

reaches of large rivers is better 

because much of the flow is 

derived from the forested 

headwaters.

More than half of the agricultural acreage in the basin is 

located in Whatcom, Skagit, and 

Snohomish Counties. Agricultural land use consists of about 60 

percent cropland and 40 percent 

pasture. Livestock produce a large 

amount of manure that is applied 

as fertilizer to cropland, sometimes in excess amounts, resulting 

in runoff of nitrogen and phosphorus to surface water and leaching 

of nitrate to ground water. Runoff 

from agricultural areas also carries 

sediment, pesticides, and bacteria 

to streams (Staubitz and others, 

1997). Pesticides and fumigantrelated compounds are present,

usually at low concentrations, in 

shallow ground water in agricultural areas.

Heavy industry is generally 

located on the shores of the urban 

bays and along the lower reaches 

of their influent tributaries, such 

as Commencement Bay and the 

Puyallup River in Tacoma and 

Elliott Bay and the Duwamish 

Waterway in Seattle. Highdensity commercial and residential development occurs primarily within and adjacent to the 

major cities. Development in 

recent years has continued 

around the periphery of these 

urban areas but has trended 

toward lower density. This trend 

has resulted in increasing urban 

sprawl in the central Puget 

Sound Basin (fig. 3).

Urban land-use activities have 

had a significant impact on the 

quality of streams in the Puget 

Sound Basin (Staubitz and 

others, 1997). Water-quality concerns related to urban development include providing 

adequate sewage treatment and 

disposal, transport of contaminants 

to streams by storm runoff, and 

preservation of stream corridors.

Water Availability Is a

Major Issue

Although surface water provides 

most of the drinking water for the 

major urban centers (fig. 4), ground 

water is used in rural areas, and reliance on ground water as a source of 

drinking water is increasing with 

urban and suburban development 

(Staubitz and others, 1997).

Water availability has been and 

will continue to be a major, longterm issue in the Puget Sound Basin. 

It is now widely recognized that 

ground-water withdrawals can 

Figure 3. Recent urban development in the Puget Sound Basin has 

been around the periphery of established urban areas.

EXPLANATION

49°

47°

CANADA

123°

121°

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

 BRITISH COLUMBIA

 PUGET

 SOUND

UNITED STATES

Oly

mpic Mountains

URBAN LAND USE IN 1970

LAND DEVELOPED FOR URBAN

 LAND USE BETWEEN 1970 AND 1990

INTERNATIONAL BOUNDARY

Everett

Seattle

Bremerton

Bellingham

Olympia

Tacoma

Cascade

Range
Introduction to the Puget Sound Basin 5 

deplete streamflows (Morgan and 

Jones, 1999), and one of the 

increasing demands for surface 

water is the need to maintain 

instream flows for fish and other 

aquatic biota.

Hydrologic Conditions 

Probably Affected Study 

Results

Surface water was sampled 

during 1996 and 1997 when rainfall and streamflows generally 

were above the 30-year average 

(fig. 5). Because of increased 

runoff during periods of rainfall, 

larger amounts of sediment, nutrients, pesticides, bacteria, and other 

contaminants may have been 

transported from the land surface 

into streams and rivers than during 

drier years. High flows due to 

runoff from paved surfaces can 

also alter stream habitat.

Figure 4. Excluding water used for hydroelectric power, 41 percent of 

water was used for domestic supply in 1995. Ground water accounted 

for 47 percent of all withdrawals.

Figure 5. Streams and rivers were sampled during 1996 and 1997 when 

streamflows generally were above the 30-year average.

Some Ground Water Is

Susceptible to Contamination

Shallow ground water (less than 

100 feet deep) in the Puget Lowlands is more susceptible to contamination in areas where the overlying 

sediments are coarse grained than 

where they are fine grained (see 

p. 16 and map, p. 20). This is 

because rainfall, or applied irrigation water, seep relatively easily 

through coarse-grained sediments 

and can transport contaminants to 

ground water.

Study Design Focuses on 

Land Use

Chemical and biological samples 

were collected from a mix of rivers 

and streams in forested, urban, and 

agricultural areas to assess overall 

quality as well as the effects of 

specific land-use practices. At some 

sites, water samples were collected 

monthly and during storms to assess 

the effects of storm runoff on 

contaminant washoff. Other sites 

were sampled only once, usually 

during normal flows.

Shallow ground water was 

sampled from aquifers in coarsegrained glacial deposits considered 

to be the most at risk to contamination. Water from these aquifers 

was sampled to assess general water 

quality and specifically to assess the 

quality of water in agricultural and 

residential areas. Monitoring wells 

and domestic wells were sampled. 

Data from a previous sampling of 

public-supply wells (Ryker and 

Williamson, 1996) are used to help 

evaluate the quality of drinking 

water and the quality of deep 

ground water. (See table 3, page 21 

for details on study design.)

0

200

400

600

800

1,000

1,200

0

20

40

60

80

100 100%

7% 9%

41%

30%

<1% <1% 1%

11%

Public supply-Combined ground water and surface water 

Public supply-Surface water

Public supply-Ground water

Self supply-Surface water

Self supply-Ground water

WATER WITHDRAWALS, IN MILLIONS OF GALLONS PER DAY

PERCENTAGE OF TOTAL WATER WITHDRAWALS

TOTAL

WITHDRAWALS

PUBLIC USE

AND LOSSES

COMMERCIAL

DOMESTIC

INDUSTRIAL

THERMOELECTRIC

MINING

LIVESTOCK

IRRIGATION

WATER WITHDRAWALS AND USE IN PUGET SOUND BASIN, 1995

STREAMFLOW, IN CUBIC

FEET PER SECOND

OND J FMAMJ J ASOND J FMAMJ J ASOND J FMAMJ J AS

1995 1996 1997 1998

Big Soos Creek 75th percentile

25th percentile

Daily streamflow

8,000

5,000

2,000

1,000

500

200

100

50

20

10
MAJOR FINDINGS 

6 Water Quality in the Puget Sound Basin

Pesticides in Surface Water 

Were Indicative of Upstream 

Land Uses, and More 

Pesticides Were Detected in 

Streams Than in Rivers

Twenty-nine pesticides were 

detected in Fishtrap Creek, which 

drains an agricultural area in the 

Nooksack River Basin (see map, 

p. 20), compared with 21 in Thornton Creek, an urban stream. In 

Fishtrap Creek, the more frequent 

detections of the herbicides atrazine 

and metolachlor, used more in 

agricultural areas, and less frequent 

detections of the herbicides dichlobenil and prometon (fig. 6), used 

more in urban areas, are consistent 

with the predominant land use in the 

drainage basin. Urbanuse pesticides in Fishtrap Creek are probably 

transported from urban 

areas in the upper and 

lower parts of the basin.

The two large rivers 

sampled for pesticides, 

the Nooksack and 

Duwamish (see map, 

p. 20), integrate landuse effects. The 

herbicides prometon, 

simazine, and tebuthiuron, which are used in 

urban settings, were 

detected frequently in 

the Duwamish River (fig. 6). 

This is indicative of the urban 

land use surrounding and 

Figure 6. Pesticides detected in small streams (A) and large rivers (B) were 

indicative of land use, but detection frequencies in large rivers were lower 

because of dilution by flows from forested headwaters.

immediately upstream from the 

sampling site. Metolachlor, an agricultural herbicide, was detected more 

often in the Duwamish River than in 

the Nooksack River, which was 

sampled in an agricultural setting. 

Metolachlor in the Duwamish River 

was likely transported from agricultural areas upstream from the mostly 

urbanized lower part of the basin, 

where samples were collected.

Pesticides transported to the 

Nooksack and Duwamish Rivers 

are diluted by the volume of highquality water from forested headwaters, resulting in lower detection 

frequencies compared with Fishtrap 

and Thornton Creeks (fig. 6). In addition to lower detection frequencies, 

fewer pesticides were detected in the 

large rivers.

Diazinon was the most frequently 

detected insecticide in both small 

streams and large rivers (fig. 6). It is 

used heavily in urban areas of the 

Puget Sound Basin, and its frequent 

detection, sometimes at concentrations exceeding the chronic guideline 

for the protection of aquatic life (table 

1), prompted a more focused study of 

pesticides in urban streams in Seattle 

and surrounding King County (see 

page 7).

Table 1. Concentrations of three insecticides were 

sometimes above chronic guidelines for the protection 

of aquatic life

1

 U.S. Geological Survey, 1999a.

Insecticide

Aquatic

life

guideline 

(micrograms per 

liter)1

Percentage

of all 

samples 

exceeding 

guideline

Site in

exceedance

and 

(percentage 

of samples)

Range of 

concentrations 

detected at the

site (micrograms per liter)

Chlorpy-

 rifos

 0.041 1 Thornton (2) 0.006–0.074

Diazinon 0.08 9 Thornton (20)

 Fishtrap (3)

 Duwamish (4)

0.003–0.501

0.004–0.113

0.004–0.083

Lindane 0.01 1 Thornton (2) 0.02

PERCENT DETECTIONS PERCENT DETECTIONS

ATRAZINE

DEETHYLATRAZINE

METOLACHLOR

DICHLOBENIL

PROMETON

SIMAZINE

TEBUTHIURON

CARBARYL

CHLORPYRIFOS

DIAZINON

MALATHION

HERBICIDES,

PRIMARILY AGRICULTURAL USAGE

HERBICIDES,

PRIMARILY URBAN USAGE INSECTICIDES

0

100

(A) Small Streams

20

40

60

80

0

100

20

40

60

80

(B) Large Rivers

Nooksack River sampled in

 an agricultural setting

Duwamish River sampled in

 an urban setting

Fishtrap Creek,

 agricultural stream

Thornton Creek,

 urban stream
Major Findings 7 

Concentrations of Pesticides in 

Surface Water Draining Urban and 

Agricultural Areas Sometimes 

Exceeded Guidelines for the 

Protection of Aquatic Life

The insecticides chlorpyrifos, 

diazinon, and lindane were sometimes 

detected at concentrations above 

chronic guidelines for the protection 

of aquatic life (table 1). Concentrations of diazinon exceeded its guideFigure 7. A comparison of pesticides detected in urban streams with retail 

sales data suggests that homeowner and nonresidential applications both are 

sources of pesticides in streams. Sales were reported in units, which represent a 

bag, bottle, or other package containing the pesticide.

line in 9 percent of all samples, and 

in Thornton Creek, concentrations 

exceeded the guideline in 20 

percent of samples. It is estimated 

that about half the 83,000 pounds 

of diazinon applied annually in the 

Puget Sound Basin are applied in 

King County (Tetra Tech Incorporated, 1988). Diazinon is the insecticide purchased most frequently by 

King County residents (fig. 7).

Pesticides Applied to Lawns and 

Gardens, As Well As Those Applied 

in Nonresidential Areas, Are 

Sources of Pesticides in Urban 

Streams

Because of the prevalence of diazinon and other pesticides in Thornton 

Creek, the USGS collaborated with 

the Washington State Department 

of Ecology and the King County 

Hazardous Waste Management 

Program to study pesticides in streams 

in 10 urban and suburban watersheds 

in King County (see map, p. 20). 

Samples were collected during April 

and May 1998 when retail sales of 

pesticides are highest (Voss and 

others, 1999), and they were collected 

during storms when runoff can transport pesticides to streams.

Because USGS and Washington 

State Department of Ecology laboratories both participated in the study, 

additional pesticides not included in 

the NAWQA study were analyzed. To 

help determine sources of pesticides 

detected, King County provided sales 

data for pesticides sold in 10 large 

home and garden stores during 1997.

Twenty-three of 98 pesticides 

analyzed for were detected in the 

urban streams. Homeowner use as a 

source of pesticides in streams is

indicated for compounds like the

herbicide 2,4-D and the insecticide 

diazinon, which were detected in all 

streams and were sold frequently in 

the home and garden stores (fig. 7). 

Some pesticides sold in stores were 

not detected in streams, indicating that 

other factors, like the rate at which a 

compound breaks down, affect the 

relation between usage and detection.

Almost half of the pesticides 

detected in the streams had no retail 

sales, indicating that they are usually 

not applied by homeowners. In urban 

areas, pesticides are also applied in 

commercial areas, along road rightsof-way, and in parks and recreational 

areas.

Herbicide Insecticide Fungicide

PERCENT

1

2

3 32 1 Unit retail sales for these herbicides total to 140,000 units.

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

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

0 20 40 60 80 100

ND

ND

ND

ND

ND

ND

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

2,4-D 

Dichlobenil 

MCPP 

Prometon 

Triclopyr 

MCPA 

Atrazine 

Simazine 

Dicamba 

Dichlorprop 

Metolachlor 

Trifluralin 

EPTC 

Napropamide 

Oxadiazon 

Acetochlor Guardian 

Tebuthiuron 

 

Diazinon 

Carbaryl 

Malathion 

gamma-HCH Chlorpyrifos 

Disulfoton 

cis-Permethrin 

 

Pentachlorophenol 

Chlorothalonil 

Triadimefon

Active 

ingredient

Trade name

example

Class

Percentage of unit retail sales within a class (herbicide, 

insecticide, or fungicide) contributed by the pesticide

Percentage of sites where pesticide was detected

No sales reported from retail outlets

Not detected at sites

 

Pendimethalin Prowl

Casoron

Mecoprop

Pramitol

Garlon

Kilsem

AAtrex

Princep

Banvel

2,4-DP

Dual

Treflan

Eptam

Devrinol

Ronstar

Spike

Diazinon

Sevin

Malathion

Lindane

Dursban

Di-syston

Ambush

Penta

Bravo

Bayleton

Weedone
8 Water Quality in the Puget Sound Basin

Historically Used Pesticides 

and PCBs Are Still Detected 

in Streambed Sediments 

and Fish Tissue

Streambed sediment and whole 

fish (sculpin, a bottom fish) tissue 

were analyzed at sites throughout 

the basin (see map, p. 20) in 1995 

for organochlorine pesticides and 

PCBs. These compounds have been 

shown to have negative impacts on 

the health of aquatic organisms as 

well as the organisms that consume 

them. More organochlorine compounds were detected in both 

streambed sediments and fish tissue 

at sites surrounded by agricultural 

and urban land uses than at sites in 

undeveloped, forest, or mixedland-use areas (fig. 8).

Figure 8. Organochlorine compounds, including the insecticide DDT and 

PCBs, in streambed sediments and fish tissue were primarily detected in 

urban and agricultural streams.

Although detection frequencies 

vary, insecticides 

in Thornton Creek 

were typical of 

those detected in 

urban streams in 

other Study Units 

throughout the 

Nation.

Areas where pesticides 

are applied in urban 

settings are often in close 

proximity to streams. 

(Photograph by Sandra 

Embrey, U.S. Geological 

Survey.)

Throughout the Nation, the insecticides diazinon, carbaryl, chlorpyrifos, 

and malathion were detected much 

more frequently in streams draining 

urban basins than in streams draining 

agricultural basins (U.S. Geological 

Survey, 1999b). Except for carbaryl, 

these pesticides also were detected 

more frequently in Thornton Creek, an 

urban stream, than in Fishtrap Creek, 

an agricultural stream (fig. 6).

Detection of these pesticides is 

related to usage. For example, diazinon 

and chlorpyrifos, which nationally rank 

1 and 4 among insecticides used for 

homes and gardens, rank 1 and 2 in unit 

sales of insecticides sold by home 

improvement stores in urban and 

suburban areas of King County (fig. 7).

Insecticides in streams are a concern 

because even at relatively low concentrations they can exceed guidelines for 

the protection of aquatic life (table 1).

Insecticides in Thornton Creek Were Also Detected in Urban

Streams Throughout the Nation

0

10

20

30

40

50

60

70

80

90

100

CARBARYL CHLORPYRIFOS DIAZINON MALATHION

FREQUENCY OF DETECTION, 

AS PERCENTAGE OF SAMPLES

Thornton Creek in

 Puget Sound Basin

Urban streams in

 other Study Units

0

1

2

3

4

5

6

7

8

9

10

11

12

NUMBER OF COMPOUNDS DETECTED

AGRICULTURAL URBAN UNDEVELOPED

AND FOREST

MIXED

LAND USE / LAND COVER

Maximum

Minimum

Average

SedimentTissue
Major Findings 9 

Fish Tissue Contamination is 

Related to Urban and Agricultural 

Land Uses

The relation between land use 

and the probability of detecting 

organochlorine compounds in fish 

(sculpin) tissue were statistically 

significant. This relation suggests 

that urban and agricultural land uses 

both contribute to the probability 

that a fish is contaminated with 

organochlorine pesticides. The 

probability of detecting total PCBs 

in fish was significantly related to 

urban land use only (Black and 

others, 2000). These relations also 

suggest that there is a land-use 

threshold below which the probability of finding organochlorine 

compounds in fish tissue is 

unlikely (fig. 9).

Organochlorine Compounds in 

Streambed Sediment and Fish 

May Be a Concern for Aquatic 

Ecosystems

Organochlorine pesticides were 

detected in streambed sediment at 

3 of 19 sites (fig. 10). At Thornton 

Creek, an urban stream, levels of 

DDE (a breakdown product of 

DDT) and DDT exceeded the 

Canadian Council of Ministers of 

the Environment’s (Canadian Council of Ministers of the Environment, 

1995) probable effects level (PEL). 

Compounds exceeding the PEL are 

likely to result in adverse effects on 

aquatic organisms. It is important to 

note that levels of DDT in Thornton 

Creek sediment were higher than 

either one of its breakdown products, DDD and DDE. This may 

indicate that land disturbances in 

the basin have reintroduced buried 

soils contaminated with DDT.

Organochlorine compounds were 

also detected in the tissue of whole 

bottom fish (sculpin) collected at 

8 of 18 study sites (fig. 11). 

Figure 10. Concentrations of organochlorine compounds in streambed sediment 

in the Puget Sound Basin sometimes exceeded Canadian probable effects levels 

(PELs). Compounds above the PELs may have negative impacts on aquatic 

organisms.

Figure 9. The probability of detecting specific organochlorine compounds in one 

or more fish (sculpin) at a site increased with the percentage of urban and agricultural land in the drainage basin. Dieldrin, cis-Chlordane, and p,p’-DDT relations 

are based on the percentage of agriculture plus urban land upstream from the 

sampling site. The total PCBs relation is based on the percent of urban land 

upstream from the sampling site.

p,p’-DDT

Total PCBs

cis-Chlordane

Dieldrin

0

20

40

60

80

100

PROBABILITY OF DETECTION IN ONE OR

MORE FISH (SCULPIN), IN PERCENT

0 20 40 60 80 100

PERCENT URBAN PLUS AGRICULTURAL LAND OR

PERCENT URBAN LAND FOR TOTAL PCBs

0

1

2

3

4

5

6

7

8

9

10

CONCENTRATION, IN MICROGRAMS PER KILOGRAM, DRY WEIGHT

FISHTRAP CREEK AT FLYNN ROAD

(AGRICULTURAL)

THORNTON CREEK NEAR SEATTLE

(URBAN)

ROCK CREEK NEAR MAPLE VALLEY

(SUBURBAN)

PEL Total Chlordane

PEL DDD

PEL DDE

PEL DDT

PEL Dieldrin

Total Chlordane

DDD

DDE

DDT

Hexachlorobenzene (HCB)

Dieldrin
10 Water Quality in the Puget Sound Basin

The largest number and highest concentrations of these compounds were in the 

fish collected from urban sites. At some 

sites, total PCBs and DDT concentrations were equal to or above the New 

York State Department of Environmental 

Conservation (NYSDEC) criteria for the 

protection of fish-eating wildlife (Newell 

and others, 1987).

Generally, the concentrations of 

organochlorine compounds in sediment 

and fish tissue were in the middle 50 

percent nationally (see Appendix). 

Occasionally, concentrations of DDE, 

total chlordane, and total DDT were in 

the upper 25 percent of those reported 

nationally.

Figure 11. Concentrations of organochlorine compounds in fish (sculpin) 

tissue from streams in the Puget Sound Basin sometimes exceeded New 

York State Department of Environmental Conservation (NYSDEC) criteria. 

Concentrations above criteria may have a detrimental effect on fish-eating 

organisms.

Organochlorine compounds are 

synthetic organic compounds containing chlorine. As generally used, 

the term refers to compounds 

containing mostly or exclusively 

carbon, hydrogen, and chlorine. 

Examples include organochlorine 

insecticides, polychlorinated 

biphenyls, and some solvents 

containing chlorine.

Chlordane (Octachloro-4,7-methanotetrahydroindane) is an organochlorine insecticide no longer registered for use in the United States. 

Technical chlordane is a mixture in 

which the primary components are 

cis- and trans-chlordane, cis- and 

trans-nonachlor, and heptachlor.

DDT (Dichloro-diphenyl-trichloroethane) is an organochlorine insecticide no longer registered for use in 

the United States.

Dieldrin is an organochlorine 

insecticide no longer registered for 

use in the United States. It is also a 

breakdown product of the insecticide aldrin.

Heptachlor epoxide is a breakdown product of the organochlorine 

insecticide heptachlor. It was used 

in the United States until the 1970s.

Hexachlorobenzene (HCB) is a 

fungicide used as a seed and soil 

treatment. It was discontinued from 

use in the United States in the 

1980s.

Polychlorinated biphenyls (PCBs)

are a mixture of chlorinated derivatives of biphenyl, marketed under 

the trade name Aroclor with a number designating the chlorine content (such as Aroclor 1260). PCBs 

were used in transformers and 

capacitors for insulating purposes 

and in gas pipeline systems as a 

lubricant. Further sale for new use 

was banned by law in 1979.

Characteristics and historical uses of organochlorine compounds detected in 

Puget Sound Basin fish tissue and streambed sediment

Whole 

sculpin 

(Cottus) 

were 

analyzed 

for 

organochlorine compounds. (Photograph by 

Ward W. Staubitz, U.S. Geological Survey.)

0

50

100

150

200

250

300

350

Total chlordane (Criterion = 500 μg/kg)

Heptachlor epoxide

Total PCBs

Total DDT

Hexachlorobenzene

Dieldrin

BERTRAND

(agricultural)

FISHTRAP

(agricultural)

JUANITA

(urban)

KELSEY

(urban)

LEACH

(urban)

MILLER

(urban)

NORTH

(urban)

THORNTON

(urban)

STREAM NAMES AND LAND USE

Heptachlor epoxide Criterion

Dieldrin Criterion

Total DDT Criterion

Total PCB Criterion

Hexachlorobenzene Criterion

CONCENTRATION, IN MICROGRAMS PER

KILOGRAM (μg/kg), WET WEIGHT
Major Findings 11 

Streams and Rivers in Developed Areas

Were Enriched with Nutrients Relative 

to Those in Undeveloped Areas

The highest average concentrations of total nitrogen 

were in small streams draining agricultural areas. The 

concentrations were nearly twice those in streams 

draining urban areas and over 40 times the average 

concentrations in streams draining undeveloped land 

(table 2). Drainage basins in agricultural areas also 

yielded the most nitrogen per square mile (fig. 12). 

Concentrations and yields of total nitrogen in Puget 

Sound Basin streams and rivers correlate with usage 

and atmospheric deposition of nitrogen in drainage 

basins (Inkpen and Embrey, 1998). Fertilizers used in 

both agricultural and urban areas, manure associated 

with dairy farms, and atmospheric deposition are 

sources of nitrogen in Puget Sound Basin rivers 

(Embrey and Inkpen, 1998).

Concentrations of Phosphorus in Some Streams and 

Rivers May Promote Excessive Plant Growth

Average concentrations of total phosphorus exceeding the USEPA desired goal of 0.1 mg/L to prevent 

excessive plant growth were detected in streams and 

rivers in all land-use areas except undeveloped land 

(table 2). Unlike total nitrogen, concentrations of total phosphorus in streams and 

rivers in the Puget Sound Basin do not 

correlate with usage and atmospheric 

deposition of phosphorus in drainage 

basins (Inkpen and Embrey, 1998). This is 

because phosphorus attaches to soil particles and usually remains close to application areas unless it is transported to rivers 

by soil erosion.

Because of the importance of erosion in 

transporting phosphorus to streams, yields 

of total phosphorus correlate with yields of 

suspended sediment. The highest yields of 

both suspended sediment and total phosphorus were in the Nooksack River at 

North Cedarville, which drains a forested 

area.

Erosion of unstable streambanks and 

landslides transport sediment and phosphorus to headwater streams in the Nooksack River Basin. Most of the unstable 

streambanks are associated with road 

construction and logging (U.S. Forest 

Service, 1995).

Table 2. Highest average concentrations of total nitrogen were in streams 

draining agricultural areas. Average concentrations of total phosphorus 

exceeding the USEPA desired goal of 0.1 mg/L to prevent excessive plant 

growth (shown in bold) were present in streams in urban, agricultural, and

forested basins 

River or stream

Average total 

nitrogen 

concentration

(milligrams per 

liter)

Average total 

phosphorus 

concentration

(milligrams per 

liter)

Basin area 

size

Land use/land cover

(dominant land use 

in mixed)1

Fishtrap 3.54 0.086 small agricultural

Newaukum 2.82 0.210 small agricultural

Thornton 1.73 0.131 small urban

Big Soos 1.20 0.054 small urban

Springbrook 1.10 0.165 small urban

Nooksack, Brennan 0.66 0.301 large mixed (agricultural)

Duwamish 0.65 0.089 large mixed (urban)

Nooksack, North 

Cedarville

0.39 0.152 large mixed (forest)

Skokomish 0.13 0.078 large mixed (forest)

North Fork Skokomish 0.07 0.012 small undeveloped

Green 0.07 0.012 small forest

1Forest land that is not logged is designated undeveloped. In basins with 

mixed land use, the land use in the part of the basin where samples were 

collected is usually considered the dominant land use.

Figure 12. Basins in agricultural areas yielded the most 

nitrogen per square mile. The forested area upstream from 

the Nooksack River at North Cedarville yielded the most 

phosphorus. In basins with mixed land use, the dominant 

land use is indicated. The Green River above Twin Camp 

Creek and North Fork Skokomish River fall into the stream 

category because their drainage basins are relatively small.

Skokomish

Nooksack

(N. Cedarville)

Nooksack

(Brennan)

Duwamish

Green

NF Skokomish

Fishtrap

Newaukum

Big Soos

Springbrook

Thornton

Forest Agricultural Urban

FOREST AND

UNDEVELOPED AGRICULTURAL URBAN

0

10

20

30

40

50

NUTRIENT YIELDS, IN POUNDS PER DAY PER SQUARE MILE

RIVERS STREAMS

MIXED LAND USE

Total nitrogen

Total phosphorus
12 Water Quality in the Puget Sound Basin

Concentrations of Nitrate and 

Phosphorus in Streams and Rivers 

Have Not Changed or Have Only 

Slightly Increased with Time

Concentrations of nitrate, one of 

the major forms of nitrogen in water, 

and of total phosphorus have not 

changed much over the period 1980 

to 1997 in several Puget Sound Basin 

rivers and streams (fig. 13). In three 

streams, nitrate concentrations have 

increased by a small amount, 

0.014 mg/L per year or less. Only in 

Figure 14. Nutrient concentrations in Newaukum Creek 

were highest during the rainy winter and spring periods. 

Concentrations were lowest during late summer-early 

fall when rainfall amounts are lowest. Figure 13. In three of six rivers and streams monitored 

by the Washington State Department of Ecology and King 

County, nutrient concentrations have remained stable from 

1980 to 1997. In three others, concentrations of nitrate have 

gradually increased with time.

Newaukum Creek did concentrations 

of both nitrogen and phosphorus 

increase over time. Although data 

were not collected to determine the 

cause, trends often reflect land-use 

changes. For example, urban development might be a factor related to 

increasing nitrate concentrations in 

Big Soos Creek and in Newaukum 

Creek, which drains an agricultural 

basin with hobby farms and residential development.

Figure 15. Peak concentrations of diazinon in Thornton Creek often 

occurred during spring rainstorms, which can produce an inch or 

more of rain in a day.

Runoff During Rainstorms 

Contributes Contaminants 

to Streams, Indicating 

Nonpoint Sources

Washoff of nutrients and pesticides during storms causes both 

seasonal and short-term temporal 

variations in concentrations. A 

typical seasonal pattern for Puget 

Sound Basin streams and rivers is 

illustrated by lower concentrations 

of nitrogen and phosphorus in 

Newaukum Creek from July 

through October when rainfall 

amounts are lowest (fig. 14).

Commonly used pesticides, such as 

diazinon, often had higher concentrations during rainstorms when they 

were washed off from areas of application (fig. 15). Even when daily 

rainfall amounts were small, less 

than 0.05 inch, diazinon concentrations increased in Thornton Creek.

Nitrate, as N Total phosphorus

Trend Trend Rate of change,

in mg/L per year

Rate of change,

in mg/L per year

Site name (land use and

cover, dominant in mixed)

No trend or no value mg/L=milligrams per liter Significant upward trend

Newaukum Creek

(agricultural)

Skokomish River

(mixed, forest)

Big Soos Creek

(urban)

Nooksack River

 at Brennan

(mixed, agricultural)

Nooksack River

 at N. Cedarville

(mixed, forest)

Green River at

 Renton Junction

(mixed, urban)

0.004

0.010

0.014 0.002

2

4

6

0

TOTAL NITROGEN,

IN MILLIGRAMS PER LITER

TOTAL PHOSPHORUS,

IN MILLIGRAMS PER LITER

0.2

0.4

0.6

0.8

0 NOVEMBERFEBRUARY

MARCHJUNEJULYOCTOBER

SEASON

EXPLANATION

Total

nitrogen

Total

phosphorus

Maximum

Median

Minimum

0

1

2

3

Streamflow

Diazinon

Rainfall

0.02

0.03

0.04

0.05

0.07

0.1

0.2

0.3

DIAZINON CONCENTRATION,

IN MICROGRAMS PER LITER

STREAMFLOW, IN CUBIC FEET PER SECOND

RAINFALL, IN INCHES

31 5 10 15

APRIL MAY

20 25 30 5 10 15 20 25

1996

20

1

40

60
Major Findings 13 

Bacteria Indicate the 

Presence of Fecal 

Contamination in Many 

Puget Lowland Streams

A study of 31 small lowland 

streams showed fecal coliform, 

E. coli, and enterococci bacteria to 

be present in every stream sampled 

during base flow. The presence of 

E. coli and enterococci bacteria is 

evidence that fecal contamination 

has occurred. During base flow, 

fecal contamination in urban 

streams could result from leaky 

sewer systems, failing septic 

systems, and direct fecal inputs 

from pets and wildlife, including 

waterfowl. In agricultural and rural 

streams, fecal contamination is 

likely to be mostly from animals, 

including farm animals (dairy and 

beef cattle, and horses). Other 

sources could be wildlife, with 

perhaps some input from onsite 

septic systems.

Concentrations of all three 

fecal-indicator bacteria frequently 

exceeded standards and criteria 

(fig. 16); 81 percent of all sites had 

concentrations of fecal coliforms 

exceeding Washington State standards, and 48 percent of all sites had 

levels of E. coli exceeding USEPA’s 

recommended concentration for 

moderate water-contact recreation. 

Because concentrations of E. coli

and enterococci are related to cases 

of gastrointestinal illness in swimmers (U.S. Environmental Protection 

Agency, 1986), there could be some 

risk of illness to children and adults 

playing and swimming in these 

accessible streams.

The types of fecal bacteria and 

their concentrations in streams were 

similar among urban, agricultural, 

and rural areas (fig. 16). However, 

concentrations of E. coli in the urban 

and agricultural streams were all 

well above those in the upper Green 

River in the forested headwaters of 

the basin.

Stream Habitat and Health 

Are Degraded in Agricultural 

and Urban Streams

During the late summer and early 

fall, between 1995 and 1998, the 

USGS and the Washington State 

Department of Ecology evaluated 

instream and riparian (streamside) 

habitat conditions at 45 sites. These 

evaluations indicated that habitat 

conditions at streams draining urban 

Figure 16. Concentrations of E. coli and enterococci bacteria exceeded U.S. 

Environmental Protection Agency recreational criteria, and fecal coliform bacteria 

exceeded Washington State standards in many lowland streams. Concentrations 

of bacteria in single samples were compared with criteria and standards. USEPA 

criteria for moderate full-body contact recreation apply to a single sample (U.S. 

Environmental Protection Agency, 1986). Washington State standards for fecal 

coliform bacteria apply to the geometric mean of concentrations in samples 

collected during a period of no more than 30 days (State of Washington, 1992). 

Because no minimum number of samples is specified, the standard is routinely 

applied to concentrations in single samples (Hallock and others, 1996).

Concentrations of bacteria in urban 

streams, which are attractive recreation 

areas, often exceed recommended 

concentrations for moderate watercontact recreation. (Photograph by Ward 

W. Staubitz, U.S. Geological 

Survey.)

1

50,000

2

5

10

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

FECAL COLIFORMS,

WASHINGTON STATE, CLASS A

ENTEROCOCCI,

 USEPA, MODERATE CONTACT RECREATION

E. COLI,

 USEPA, MODERATE CONTACT RECREATION Maximum

Median

Minimum

Fecal coliform

E. coli

Enterococci

CONCENTRATIONS, IN COLONIES PER 100 MILLILITERS

AGRICULTURAL

AND RURAL

URBAN FOREST No data No data

STANDARDS AND CRITERIA

EXPLANATION
14 Water Quality in the Puget Sound Basin

and agricultural basins were significantly different from those 

at streams draining basins with forest and undeveloped land 

(fig. 17). Compared with either urban or agricultural sites, 

forest and undeveloped stream sites had a much higher percentage of cobble substrate, ideal for a diverse population of 

aquatic organisms, and a lower percentage of sand, detrimental 

to salmon spawning. In addition, forest and undeveloped sites 

had a much higher variability in water flow velocities than 

either urban or agricultural sites. More variability in flow 

velocities increases habitat diversity and wildlife diversity. 

Midday water temperatures were also much lower in the 

forested streams. The higher temperatures observed in the 

agricultural and urban streams are not ideal for native salmon 

and other aquatic organisms.

Human Activities Have Altered Aquatic 

Invertebrate Communities

As part of the USGS and Washington State Department of 

Ecology habitat data collection, aquatic invertebrates (insects 

and worms) were also collected from multiple riffle habitats at 

all 45 sites. A number of invertebrate community measures 

were examined to evaluate the status and quality of the aquatic 

invertebrate community. For each invertebrate community 

measure, values were lower, significantly so in some cases, at 

the urban and agricultural sites (fig. 18). 

Figure 17. Values of selected habitat variables indicate that habitat conditions are degraded in agricultural and urban streams compared with streams 

in forest and undeveloped land. For each habitat variable, except temperature, multiple measurements were taken within a 330- to 660-foot-long 

stream reach at each study site.

Figure 18. As indicated by the average values of six 

different invertebrate community indicators of stream 

ecosystem conditions, conditions were better at sites in 

forest and undeveloped land than at sites in urban and 

agricultural areas. Lower values suggest a more 

degraded stream site. Taxa are different types of 

invertebrates.

Urban development and agriculture can 

reduce habitat quality, alter typical stream 

flows, and increase chemical contaminants 

and temperatures, all of which are reflected 

in invertebrate community measures. A 

reduction in the total number of different 

invertebrates, stoneflies, mayflies, intolerant invertebrates, and percentage of predatory invertebrates indicates stream ecosystem degradation. For example, the total 

number of different invertebrates was 

much higher at the forest and undeveloped 

sites. A greater number of different invertebrates indicates a less degraded stream system capable of supporting more numerous 

desirable species such as salmon.

A summation of many invertebrate 

community measures is also shown in 

figure 18. This measure is known as a 

Benthic Index of Biological Integrity 

(BIBI) and is an overall indication of the 

biological integrity or health of a particular stream site (Black and MacCoy, 

2000). As seen in figure 18, urban and 

agricultural systems have lower biological 

integrity scores than the forest and 

undeveloped sites.

0

20

40

60

0.1

0.2

0.3

0.4

0.5

0.6

STREAM VELOCITY VARIATION

0.8

0.4

1.2

1.6

AGRICULTURAL

12

14

16

18

MIDDAY WATER TEMPERATURE,

IN DEGREES CELSIUS

AGRICULTURAL URBAN URBAN

AGRICULTURAL UNDEVELOPED AGRICULTURAL URBAN

AND FOREST

UNDEVELOPED

AND FOREST

URBAN

SITE TYPE SITE TYPE

UNDEVELOPED

AND FOREST

UNDEVELOPED

AND FOREST

Average Range (95% of data)

PERCENT COBBLE

(64 256 MILLIMETERS) SUBSTRATE

PERCENT SAND

(0.06 2 MILLIMETERS) SUBSTRATE

0

10

20

30

40

NUMBER OF INVERTEBRATE TAXA,

PERCENTAGE OF PREDATORS, OR BENTHIC INDEX

OF BIOLOGICAL INTEGRITY SCORE

TOTAL OF ALL DIFFERENT

INVERTEBRATE TAXA 

TOTAL STONEFLY

INVERTEBRATE TAXA

TOTAL MAYFLY

INVERTEBRATE TAXA

TOTAL INTOLERANT

INVERTEBRATE TAXA

PERCENT PREDATOR

INVERTEBRATE TAXA

BENTHIC INDEX

(BIBI) SCORE

Undeveloped and forest

Urban

Agricultural

Average Range (95% of data)
Major Findings 15 

Streams in Urban and Agricultural Areas 

Have Less Than Optimal Amounts of 

Forest and Undeveloped Land to Support 

Healthy Aquatic Invertebrate 

Communities

A total of 46 different aquatic invertebrate taxa were identified at 45 sites 

throughout the Puget Sound Basin. Of the 

46, only 4 taxa prefer watersheds with low 

forest/undeveloped land cover, whereas 

19 taxa prefer watersheds with high 

forest/undeveloped land cover (fig. 19). 

These results indicate that streams in 

watersheds dominated by urban and agricultural land are optimally suited for only a 

few of the different taxa and many of these 

taxa are indicators of degraded stream ecosystems. Watersheds dominated by forest 

and undeveloped land are preferred by a 

much larger number of different invertebrate taxa, many of which are indicators of 

healthy stream systems.

Figure 19. 

More different 

aquatic invertebrate types 

(taxa) prefer 

streams that 

have watersheds with 

greater than

75 percent 

forest/undeveloped land 

cover. Each 

bar represents 

the preferred 

range of 

forest/undeveloped land cover 

for the specified number of invertebrate taxa out of the 46 taxa identified 

in the Puget Sound Basin. An animal is healthiest when it is in its preferred range. This figure indicates that more different invertebrate taxa 

prefer sites in forested/undeveloped watersheds, but not that more 

invertebrate taxa or total numbers of invertebrates were found at these 

sites. The method used to determine preferred land-cover percentages 

was based on the work of Line and others (1994).

In the Puget Sound Basin, 

aquatic invertebrates collected at 

the 11 fixed monitoring sites were 

compared with those collected at 

140 NAWQA sites nationwide. 

An Invertebrate status index

(Tom Cuffney, U.S. Geological 

Survey, written commun., 2000) 

was developed by averaging 11 

invertebrate metrics that summarized changes in richness, tolerance, food preference, and 

dominance associated with waterquality degradation. Invertebrate 

status scores in the basin ranged 

from low (less degraded) for 

streams in forest and undeveloped 

areas to high (more degraded) for 

other streams. As indicated by the 

invertebrate status scores, some 

Puget Sound Basin streams are 

highly degraded. This is the result 

Invertebrate status 

index by land use 

and cover for Puget 

Sound Basin sites 

in relation to 

national conditions. A low invertebrate status index 

score represents a 

less degraded 

stream site. *Mixed 

land uses can have 

an agricultural, 

urban, or forestry 

influence (table 2).

of poor habitat conditions and possibly water chemistry. As shown in 

figure 17, high midday water temperatures and percent sand were 

observed in urban and agricultural 

streams, both of which have 

negative effects on aquatic organisms. In addition, numerous pesticides, some at concentrations above 

guidelines set to protect aquatic life, 

were detected at these sites (see 

Appendix).

Puget Sound Stream Invertebrate Status Ranged from High to

Low When Compared with National Levels

0

5 4 different taxa

prefer this range

10

15

20

NUMBER OF DIFFERENT INVERTEBRATE TYPES (TAXA)

AT THEIR PREFERRED LAND COVER

PERCENTAGE OF FOREST OR UNDEVELOPED LAND COVER

30 45 60 75 90

8 different taxa

prefer this range

15 different taxa

prefer this range

19 different taxa

prefer this range

0

20

40

60

80

100

INVERTEBRATE STATUS INDEX

INCREASING STREAM DEGRADATION

UNDEVELOPED

AND FOREST AGRICULTURAL URBAN MIXED* ALL SITES

LAND USE / LAND COVER

National range

Puget Sound value

75th percentile

25th percentile
16 Water Quality in the Puget Sound Basin

Seattle

Puget

Sound

EXPLANATION

HIGHEST

LOWEST

UNKNOWN

 (PRIMARILY BEDROCK AREAS)

INCREASING RISK OF GROUNDWATER CONTAMINATION

Cascade

Range

Oly

mpic Mountains

 BRITISH 

COLUMBIA

CANADA

UNITED STATES

49°

47°

123°

121°

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

Ground-Water Quality is 

Generally Good

Prior to conducting field studies, 

an analysis of existing data was 

conducted to determine which 

Puget Sound Basin aquifers are 

most at risk to contamination. Unconfined aquifers that are overlain 

by coarse-grained glacial deposits 

(see map, p. 20) were found to be 

the most susceptible to contamination (see sidebar). Aquifers in 

coarse-grained glacial deposits in 

the Puget Sound Basin are collectively referred to as the Fraser 

aquifer. Three studies were conducted in the unconfined part of the 

Fraser aquifer (Inkpen and others, 

2000). A study-unit survey was 

conducted by randomly selecting 

30 domestic wells without regard to 

land use to evaluate the overall 

quality of shallow ground water. 

Ground-water-quality studies were 

also conducted in residential areas 

in Pierce and Thurston Counties 

and in an agricultural area in Whatcom County (see map, p. 20) to examine the influence of these important 

land-use categories on shallow ground 

water. Shallow ground water in all 

parts of the Fraser aquifer sampled is 

used for domestic supplies.

The study-unit survey results indicate that ground water is of generally 

good quality, as only one well did not 

meet a drinking-water standard (for 

nitrate). Nitrate was detected in 

Figure 20. Median 

nitrate concentrations in shallow 

ground water sampled for the studyunit survey (varied 

land use) were low. 

Higher nitrate concentrations were 

more common in 

both the residential 

land-use and agricultural land-use 

studies.

Predicting Ground-Water 

Susceptibility and Vulnerability

A statistical model (Tesoriero and Voss, 

1997; Erwin and Tesoriero, 1997) was 

created to predict which areas are (1) most 

likely to become contaminated if sources of 

contaminants are present (susceptibility) 

and (2) at the greatest risk of contamination, 

based on current land-use practices (vulnerability). Well depth, surficial geology, and 

land use were the factors that significantly 

correlated with elevated nitrate concentrations and were used in the models. Shallow 

ground water in areas with coarse-grained 

glacial deposits at the surface were the most 

susceptible to contamination. These areas 

become increasingly vulnerable to nitrate 

contamination as the amount of agricultural 

and urban land use increases. Vulnerable 

areas include the intensive agricultural areas 

in the northern part of the Study Unit as 

well as urban areas extending north and 

south of Seattle.

most wells, but the concentrations 

were low, having a median concentration of 1.0 mg/L (fig. 20). Pesticides 

were detected in 20 percent of studyunit survey wells (fig. 21) but were 

present at low concentrations (less 

than 0.2 μg/L) (micrograms per liter) 

and were well below drinking-water 

standards or guidelines. Based on 

data from a previous study (Ryker 

and Williamson, 1996), pesticides 

were not detected in wells more than 

Map shows 

risk of groundwater contamination 

(vulnerability) 

by nitrate. 

Map results 

are based 

on predicted 

probabilities 

of elevated 

nitrate concentrations 

in shallow 

ground water.

VARIED LAND USE

(Study-Unit Survey) (Land-Use Studies)

RESIDENTIAL AGRICULTURAL

5

10

0

15

Drinking-Water Standard

Median value

for 30 samples

Median value

for 27 samples

Median value

for 22 samples

MEDIAN NITRATE CONCENTRATION,

IN MILLIGRAMS PER LITER AS N
Major Findings 17 

120 feet deep (Bortleson and Ebbert, 

2000). Volatile organic compounds 

were detected frequently (80 percent 

of wells sampled) but were present 

at low concentrations (less than 

1 μg/L).

Radon concentrations exceeded 

the proposed drinking-water 

standard of 300 picocuries per liter 

(U.S. Environmental Protection 

Agency, 1999a) in about 50 percent 

of the domestic and monitoring 

wells sampled for radon (table 3, 

p. 21). Radon is a naturally occurring product from the decay of uranium. The median concentration of 

radon in ground water in the Puget 

Sound Basin was 320 picocuries per 

liter. Elevated radon concentrations 

are by no means unique to the Puget 

Sound Basin. In fact, radon concentrations in ground water collected 

for NAWQA studies throughout the 

Nation exceeded the proposed standard more often and had a higher 

median value (420 picocuries per 

liter) than in the Puget Sound Basin 

(Wentz and others, 1999).

Nitrate Concentrations in 

Shallow Ground Water 

Beneath Residential Areas 

Were Elevated, but 

Concentrations of Other 

Compounds Were Low

Although nitrate concentrations 

in shallow ground water beneath the 

residential areas in Pierce and 

Thurston Counties were elevated 

compared with those in ground 

water sampled by the study-unit 

survey (fig. 20), only one sample 

exceeded the drinking-water standard. Stable isotope measurements 

of nitrogen in nitrate suggest that 

septic-system effluent is a significant source of nitrate in unsewered 

areas. Additional nitrate sources are 

indicated by the similar concentrations of nitrate in sewered and 

unsewered areas (Inkpen and others, 

2000). Some nitrate in ground water 

in unsewered areas and most nitrate 

in sewered areas is likely from the 

application of fertilizers to lawns 

and gardens. 

Figure 21. A pesticide was detected in less than 15 

percent of shallow ground-water samples beneath 

residential areas, and the most frequently detected 

compounds were each detected in less than 10 percent 

of these samples.

Pesticides Were Rarely Detected in 

Ground Water Beneath Residential 

Areas

In spite of the vulnerability of the 

unconfined Fraser aquifer, only a few 

pesticides were detected (fig. 21) and 

these were at low concentrations (less 

than 0.2 microgram per liter) beneath 

residential areas developed since 

1970. These results suggest that 

pesticides currently used in residential 

areas may pose little risk to ground 

water. However, it should be noted 

that several commonly used pesticides 

(glyphosate, for example) were not 

analyzed.

Volatile Organic Compounds 

Were Detected Frequently at Low 

Concentrations in Ground Water 

Beneath Residential Areas

Although volatile organic compounds (VOCs) were detected in over 

90 percent of shallow ground-water 

samples in residential areas, concentrations were low (fig. 22). Most 

detections were less than 0.05 μg/L, 

Figure 22. Volatile organic compounds were frequently 

detected at low concentrations in shallow ground water 

beneath residential areas.

AT LEAST ONE PESTICIDE DETECTED

DEETHYLATRAZINE

ATRAZINE

OXAMYL

SIMAZINE

CARBOFURAN

0

10

20

30

40

50

60

70

80

PERCENT DETECTIONS

Agricultural

Varied land use

Urban

None detectedNone detectedNone detectedNone detected

PERCENT DETECTIONS

CONCENTRATION RANGE OF

 DETECTED VALUES 

MEDIAN OF DETECTED VALUES

0.01

0.1

1

10

0.001

CONCENTRATION RANGE OF DETECTED

VALUES, IN MICROGRAMS PER LITER

1,3- and 1,4-DIMETHYLBENZENE

ETHYLBENZENE

1,1,1-TRICHLOROETHANE

TRICHLOROMETHANE

METHYLBENZENE

1,2-DIMETHYLBENZENE

TETRACHLOROETHENE

10

20

30

40

50

60

70

0

PERCENT DETECTIONS

EXPLANATION
18 Water Quality in the Puget Sound Basin

Cultivated land

Riparian zone Fishtrap

Creek

Low Nitrate,

High Nitrogen Gas

High Nitrate, Low Nitrogen Gas

and none was above drinking-water 

standards or guidelines. Solvents, 

chlorinated by-products, and fuelrelated compounds were the most 

commonly detected VOCs.

High Nitrate Concentrations 

and Fumigant-Related 

Compounds Were Detected

in Shallow Ground Water 

Beneath an Agricultural Area

Nitrate concentrations in more 

than half of the shallow ground 

water sampled for the agricultural 

land-use study exceeded the drinking-water standard. Major sources 

of nitrate are animal manure from 

poultry and dairy operations and 

fertilizers applied to crops. High 

concentrations of nitrate have persisted for many years in wells sampled in this aquifer (Hii and others, 

1999), suggesting that land applications of manure and inorganic fertilizers are contributing nitrate to 

this aquifer at a sufficient rate to 

sustain these levels (fig. 23).

Figure 23. Nitrate concentrations in shallow ground water often exceeded the 

drinking-water standard (10 milligrams per liter), with high concentrations persisting for many years. Nitrate concentrations in deeper ground water, while elevated, 

generally met the drinking-water standard. Both the shallow and deeper ground 

water are used for domestic supplies.

Reactions in the Riparian Zone 

Remove Nitrate from Ground 

Water

Nitrate concentrations in ground 

water in the agricultural land-use study 

area commonly 

exceeded 10 mg/L, 

a concentration 

that can promote excessive plant 

growth in streams where this ground 

water discharges. A detailed analysis of water-quality changes along 

ground-water flow paths was 

conducted in this area (flow-path 

study area, p. 20). High nitrate 

concentrations persisted throughout 

much of the shallow aquifer. It was 

not until ground water reached the 

riparian zone of Fishtrap Creek that 

nitrate concentrations decreased to 

low levels (fig. 24). A decrease in 

nitrate concentrations in ground 

water concurrent with an increase in 

nitrogen gas (N2) concentrations in 

this zone is evidence that nitrate is 

being converted to N2 by denitrification (Tesoriero and others, 2000).

High Concentrations of 1,2-

Dichloropropane Were Probably 

Caused by Applications of Older 

Fumigant Formulations

The most commonly detected 

volatile organic compounds in the 

agricultural land-use study area were 

associated with the application of 

fumigants to soils prior to planting. 

One or more fumigant-related compounds (1,2-dichloropropane, 1,2,2-

trichloropropane, and 1,2,3-trichloropropane) were detected in over half of 

the samples. Each of these compounds 

is present in varying amounts in 

historically and/or presently used 

fumigants. Concentrations of 1,2-

dichloropropane in water from two 

wells were above the drinking-water 

standard for this compound (fig. 25).

The amount of 1,2-dichloropropane 

and 1,2,3-trichloropropane in fumigant formulations has dropped substantially over the past few decades 

(Zebarth and others, 1998), while the 

amount of 1,2,2-trichloropropane has 

decreased only slightly. 

Figure 24. Nitrate concentrations in 

ground water remain high until water 

seeps through stream sediments that 

favor microbial denitrification. This 

process can effectively transform nitrate 

to nitrogen gas before the water 

discharges to the stream.

0

5

10

15

20

25

30

35

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999

NITRATE AS N, IN MILLIGRAMS PER LITER

Shallow well (30 feet) in agricultural area

Deeper well (75 feet) in agricultural area

Drinking-water standard
Major Findings 19 

Figure 25. Fumigant-related compounds were detected 

frequently in shallow ground water in the agricultural landuse study area. Concentrations of 1,2-dichloropropane 

exceeded the drinking-water standard in two samples.

Figure 26. Based on the relative amounts of chloropropanes in samples, higher concentrations of 1,2-

dichloropropane are likely derived from older fumigant 

formulations.

The relative amounts of these 

chloropropanes in ground water 

were compared with those present in 

fumigant formulations to determine 

the origin of these compounds in 

ground water (Tesoriero and others, 

in press). Results indicate that high 

concentrations of 1,2-dichloropropane 

in ground water are largely due to older 

formulations (fig. 26).

Areas that exceed air-quality 

standards for carbon monoxide are 

required to use a fuel oxygenate to 

comply with the Clean Air Act of 

1990. Methyl tert-butyl ether 

(MTBE) is the most widely used 

oxygenate in the United States. 

However, frequent detections of 

MTBE, sometimes high concentrations, in ground water in areas 

where this compound is used has 

caused the USEPA to recommend 

that it be discontinued or reduced 

(U.S. Environmental Protection 

Agency, 1999b). MTBE is used in 

the Canadian part of the Puget 

Sound Basin but not in the U.S. 

part. Not surprisingly, detections of 

this compound were more frequent 

in the Canadian part of the Study 

Unit. When detected, MTBE concentrations were low (less than 

The detection 

frequency of 

MTBE in shallow 

ground water in 

the Puget Sound 

Basin was less 

than detection 

frequencies in 

other parts of the 

Nation (Squillace, 

1999). Ethanol, 

not MTBE, is used 

as a fuel oxygenate in the U.S. 

part of the Puget 

Sound Basin.

0.2 microgram per liter). Low 

concentrations of MTBE are likely 

derived from nonpoint sources, such 

as stormwater runoff or atmospheric 

deposition, or from diluted point 

sources (Squillace and others, 1996).

MTBE Was Rarely Detected in Ground Water in the

Puget Sound Basin

0.01

0.1

1

10

100

0.001 CONCENTRATION, IN MICROGRAMS PER LITER

Health advisory for

drinking water

Drinking-water standard

1,2-dichloropropane

1,2,2-trichloropropane

1,2,3-trichloropropane

Total number

of samples

Number of samples

 with nondetectable

 concentrations

26 28 49

59 48 59

FUMIGANT-RELATED COMPOUNDS INCREASING PROPORTION OF OLDER FUMIGANT FORMULATION

0.01

0.10

1

10

100

CONCENTRATION OF 1,2-DICHLOROPROPANE IN

GROUND WATER, IN MICROGRAMS PER LITER

U.S. PART OF

PUGET SOUND BASIN NAWQA

CANADIAN PART OF PUGET SOUND BASIN NAWQA

PUGET SOUND BASIN NAWQA

NATIONWIDE NAWQA,

MTBE NOT USED

NATIONWIDE NAWQA,

MTBE USED

0

5

10

15

20

25

30

PERCENT DETECTIONS OF MTBE

Percent detections above

 0.04 microgram per liter

0%

2%

21% 21%

1.5%

Percent detections above

 0.2 microgram per liter
20 Water Quality in the Puget Sound Basin

STUDY UNIT DESIGN 

The Puget Sound Basin study was designed to 

address local and national goals of providing widely 

comparable water-quality data focused on stream 

chemistry, stream ecology, and ground-water chemistry.

Of the 12 major and numerous minor tributaries to 

the Puget Sound, sampling was concentrated in four 

representative drainage basins: the Nooksack and 

Green River Basins with varied land uses, the Thornton 

Creek Basin in a totally urban environment, and the 

Skokomish River Basin, which is mostly forested.

collected at 14 other sites. Two-thirds of the sites 

were within the Puget Lowlands, while the remainder 

were in other ecoregions (Black and Silkey, 1998).

Some sampling was done outside these areas for 

special studies, such as the study of pesticides in 

urban streams.

Wells sampled for the survey of ground-water 

quality in the Study Unit were distributed throughout 

the Puget Lowlands. Agricultural effects on groundwater quality and changes in quality along flow paths 

were evaluated using wells located in the lower Nooksack River Basin. Wells sampled in residential areas 

surrounding Olympia and Tacoma were used for 

determining urban land-use effects on shallow 

ground-water quality.

Stream ecology, bed sediment, and aquatic biota 

sampling was done at all the fixed stream-chemistry 

sites, and one or more of these types of samples were 

Nooksack

River Basin

Skokomish

River Basin

Thornton

Creek Basin

Green

River Basin

47°

STREAM CHEMISTRY

EXPLANATION

DRAINAGE BASINS

WHERE SITES WERE

 SAMPLED MONTHLY

 AND DURING STORMS

MAJOR RIVERS

BASIC FIXED SITE

INTENSIVE FIXED SITE

STUDY OF PESTICIDES

 IN URBAN STREAMS

Nooksack River at

North Cedarville

(mixed land use)

Fishtrap Creek

(agricultural)

Nooksack River at Brennan

(mixed land use)

Springbrook Creek

(urban)

Big Soos Creek

(urban)

Newaukum Creek

(agricultural)

Green River above

Twin Camp Creek

(forest)

Duwamish River

(mixed land use)

Skokomish River

near Potlatch

(mixed land use)

North Fork

Skokomish River

(undeveloped)

Thornton Creek (urban)

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

49°

123°

121°

49°

47°

EXPLANATION

ECOREGIONS

ECOLOGY STUDIES

STREAM ECOLOGY

123°

121°

COAST RANGE

PUGET LOWLANDS

CASCADES

NORTH CASCADES

FIXED SITE

SYNOPTIC SITE

BED SEDIMENT AND

TISSUE SITE 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

Sound

Puget

EXPLANATION

ALLUVIUM

COARSE-GRAINED

 GLACIAL DEPOSITS

FINE-GRAINED

 GLACIAL DEPOSITS

BEDROCK

INTERNATIONAL BOUNDARY

GROUND WATER

URBAN LAND-USE STUDY

 AREAS (27 WELLS)

STUDY-UNIT SURVEY WELLS

AGRICULTURAL LAND-USE

 STUDY AREA (22 WELLS)

 AND FLOW-PATH STUDY

 AREA (16 WELLS)

GROUND-WATER CHEMISTRY

49°

47°

123°

121°

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0
Study Unit Design 21 

Table 3. Summary of data collection in the Puget Sound Basin, 1994–981

Study

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

Sampling frequency 

and period

Stream Chemistry

 Basic fixed 

sites–general 

water quality

Streamflow, dissolved oxygen, pH, alkalinity, specific 

conductance, temperature, nutrients, major ions, trace 

elements, organic carbon, and suspended sediment were 

measured to determine occurrence and concentration.

Streams draining basins ranging in size 

from 12 to 790 square miles, reflecting 

forest and mixed land use, and widely 

distributed geographically within the 

Study Unit.

7 Monthly plus storms

Mar. 1996–Apr. 1998

Intensive fixedsites–pesticides and 

VOCs

Above constituents plus 87 pesticides and 85 volatile 

organic compounds.

Sites selected for closer proximity to and 

more direct influence from agricultural 

and urban land uses plus integration of 

mixed-use larger basins.

3

1

Weekly to monthly

Mar. 1996–May 1997

Weekly to monthly

Mar. 1996–May 1998

Synoptic

sites–pesticides

Streamflow, pH, specific conductance, temperature plus 

pesticides during varying flow conditions to relate occurrences and concentrations to retail sales of pesticides.

Sites predominantly influenced by urban 

residential land use plus 1 reference site.

13 2 to 4 samples

over storm hydrograph

Apr.–May 1998

Contaminants 

in bed 

sediment

Trace elements and organic compounds to determine 

occurrence and distribution in streambed sediment.

Depositional zones of all basic and 

intensive stream-chemistry sites plus 

additional sites.

19 Once

Sept. 1995

Contaminants 

in fish tissue

Trace elements and organic compounds in the tissue of 

whole fish.

Same sites from which bed sediment 

samples were collected.

18 Once

Sept. 1995

Stream Ecology

Fixed sites Invertebrate, algae, and fish communities, streamflow, 

basic water chemistry, and riparian habitat conditions

surveyed to assess biological communities in the basin.

Sites collected with basic and intensive 

stream-chemistry sites and having contributing drainage areas from 12 to 790 

square miles.

11 Annually

1995–97

Synoptic Invertebrate, algae, and fish communities, streamflow, 

nutrients, and habitat conditions surveyed to determine 

land-use effects on biological communities.

4 bed sediment and tissue sites and 10 

other sites influenced by various land 

uses, with contributing drainage areas 

ranging from 3 to 48 square miles.

14 Once

Sept.–Oct. 1996

Ground-Water Chemistry

Study Unit–

varied land 

use

Nutrients, major ions, pesticides, volatile organic 

compounds, and radon in shallow, unconfined glacial 

outwash aquifer to assess the drinking-water quality of 

domestic wells in the Fraser aquifer.

Existing domestic supply wells widely 

distributed through the Puget Lowlands.

30 Once

1996

Land use–

residential

Above compounds to determine effects of urban land use 

on ground-water quality in the Fraser aquifer. One-half of 

the wells were sampled for radon.

Monitoring wells in urban residential 

areas with both sewer and private septic 

systems.

27 Once

1996–97

Land use–

agricultural 

Above compounds, except radon, to determine effects of 

agricultural land use on ground-water quality in the 

Fraser aquifer.

Monitoring wells (18) and existing 

domestic supply wells (4) in an area of 

intensive row crops (raspberries, for 

example).

22 Once

1997–98

Flow path–

agricultural

Above compounds, except radon, to determine changes in 

water quality occurring as water moves from recharge to 

discharge areas.

Shallow and deep monitoring wells along 

flow paths in an agricultural watershed. 

16 Varied

1997–98

Special Studies

Synoptic

study–microbiology and 

wastewater 

chemicals

Turbidity, pH, specific conductance, temperature, wastewater chemicals, fecal-indicator bacteria, coliphage, and 

coliphage serotypes to determine occurrence and distribution in the Puget Lowlands and infer sources of fecal 

contamination.

Sites predominantly influenced by urban 

and agricultural land use.

31 Once

Aug. 1998

Land use and 

scale

Invertebrates, instream habitat, and riparian condition data 

from USGS and Washington State Department of Ecology sites (common protocol) were combined to evaluate 

land-use impacts at different spatial scales.

Indicator sites with smaller drainage 

basins and mixed land uses.

20 USGS

25 WDOE

Annually

Aug.–Sept. 1995–97

Drinking-water 

assessment–

pesticides

Pesticides collected in previous study used to estimate 

detection probability.

Public-supply wells throughout the 

Study Unit.

78 Once

1994

 1Most data were collected 1996–98.
22 Water Quality in the Puget Sound Basin

GLOSSARY

Aquatic guidelines - Specific levels of 

water quality which, if reached, 

may adversely affect aquatic life. 

These are nonenforceable guidelines issued by a governmental 

agency or other institution.

Aquifer - A water-bearing layer of 

soil, sand, gravel, or rock that will 

yield usable quantities of water to 

a well.

Atmospheric deposition - The transfer of substances from the air to 

the surface of the Earth, either in 

wet form (rain, fog, snow, dew, 

frost, hail) or in dry form (gases, 

aerosols, particles).

Base flow - Sustained, low flow in a 

stream; ground-water discharge is 

the source of base flow in most 

places.

Basic fixed sites - Sites on streams at 

which streamflow is measured 

and samples are collected for 

temperature, salinity, suspended 

sediment, major ions and metals, 

nutrients, and organic carbon to 

assess the broad-scale spatial and 

temporal character and transport 

of inorganic constituents of 

streamwater in relation to hydrologic conditions and environmental settings.

Benthic invertebrates - Insects, mollusks, crustaceans, worms, and 

other organisms without a backbone that live in, on, or near the 

bottom of lakes, streams, 

or oceans.

Breakdown product - A compound 

derived by chemical, biological, 

or physical action upon a pesticide. The breakdown is a natural 

process that may result in a more 

toxic or a less toxic compound 

and a more persistent or less 

persistent compound.

Chlorinated solvent - A volatile 

organic compound containing 

chlorine. Some common solvents 

are trichloroethylene, tetrachloroethylene, and carbon tetrachloride.

Coliphages - Bacteriaphages, a type of 

virus, that infect and replicate in 

coliform bacteria and appear to be 

present wherever total and fecal 

coliforms are found.

Coliphage serotypes - Groups of coliphages that can be identified and 

used to infer sources of coliform 

bacteria.

Community - In ecology, the species 

that interact in a common area.

Denitrification - A process by which 

oxidized forms of nitrogen such 

as nitrate (NO3

-

) are reduced to 

form nitrites, nitrogen oxides, 

ammonia, or free nitrogen: 

commonly brought about by the 

action of denitrifying bacteria and 

usually resulting in the release of 

nitrogen to the air.

Detection limit - The minimum concentration of a substance that can 

be identified, measured, and 

reported within 99 percent confidence that the analyte concentration is greater than zero; 

determined from analysis of a 

sample in a given matrix containing the analyte.

Drainage basin - The portion of the 

surface of the Earth that contributes water to a stream through 

overland runoff, including tributaries and impoundments. 

Drinking-water standard or guideline - A threshold concentration 

in a public drinking-water supply, 

designed to protect human health. 

As defined here, standards are 

U.S. Environmental Protection 

Agency regulations that specify 

the maximum contamination 

levels for public water systems 

required to protect the public 

welfare; guidelines have no regulatory status and are issued in an 

advisory capacity.

Ecoregion - An area of similar 

climate, landform, soil, potential 

natural vegetation, hydrology, or 

other ecologically relevant 

variables. 

Fecal bacteria - Microscopic singlecelled organisms (primarily fecal 

coliforms and fecal streptococci) 

found in the wastes of warmblooded animals. Their presence 

in water is used to assess the 

sanitary quality of water for 

body-contact recreation or for 

consumption. Their presence 

indicates contamination by the 

wastes of warm-blooded animals 

and the possible presence of 

pathogenic (disease producing) 

organisms.

Flow-path study - A study to examine 

the relations of land-use practices, 

ground-water flow, and contaminant occurrence and transport. A 

flow-path study is conducted 

within a land-use study.

Freshwater chronic criteria - The 

highest concentration of a contaminant that freshwater aquatic 

organisms can be exposed to for 

an extended period of time (4 

days) without adverse effects. 

See also Water-quality criteria.

Fumigant - A substance or mixture of 

substances that produces gas, 

vapor, fume, or smoke intended to 

destroy insects, bacteria, or 

rodents.

Habitat - The part of the physical 

environment where plants and 

animals live.

Headwaters - The source and upper 

part of a stream.

Intensive fixed sites - Basic fixed 

sites with increased sampling frequency during selected seasonal 

periods and analysis of dissolved 

pesticides and volatile organic 

compounds for 1 year. Most 

NAWQA Study Units have one to 

two integrator intensive fixed 

sites and one to four indicator 

intensive fixed sites.

Intolerant organisms - Organisms 

that are not adaptable to human 

alterations to the environment and 

thus decline in numbers where 

human alterations occur. See also 

Tolerant species.
Glossary 23

Land-use study - A study that is a 

subset of the study-unit survey 

and has the goal of relating the 

quality of shallow ground water 

to land use. See also Study-unit 

survey.

Load - General term that refers to a 

material or constituent in solution, in suspension, or in transport; usually expressed in terms 

of mass or volume.

Median - The middle or central value 

in a distribution of data ranked in 

order of magnitude. The median 

is also known as the 50th 

percentile.

Metabolite - A substance produced in 

or by biological processes.

Micrograms per liter (μg/L) - A unit 

expressing the concentration of 

constituents in solution as weight 

(micrograms) of solute per unit 

volume (liter) of water; equivalent to one part per billion in most 

streamwater and ground water. 

One thousand micrograms per 

liter equals 1 mg/L.

Milligrams per liter (mg/L) - A unit 

expressing the concentration of 

chemical constituents in solution 

as weight (milligrams) of solute 

per unit volume (liter) of water; 

equivalent to one part per million 

in most streamwater and ground 

water. One thousand micrograms 

per liter equals 1 mg/L.

Nonpoint source - A pollution source 

that cannot be defined as originating from discrete points such 

as pipe discharge. Areas of fertilizer and pesticide applications, 

atmospheric deposition, manure, 

and natural inputs from plants and 

trees are types of nonpoint source 

pollution.

Nutrient - Element or compound 

essential for animal and plant 

growth. Common nutrients in 

fertilizer include nitrogen, 

phosphorus, and potassium.

Pesticide - A chemical applied to 

crops, rights of way, lawns, or 

residences to control weeds, 

insects, fungi, nematodes, 

rodents, or other "pests."

Picocurie (pCi) - One trillionth 

(10–12) of the amount of radioactivity represented by a curie 

(Ci). A curie is the amount of 

radioactivity that yields 3.7 x 

1010 radioactive disintegrations 

per second (dps). A picocurie 

yields 2.22 disintegrations per 

minute (dpm) or 0.037 dps.

Radon - A naturally occurring, colorless, odorless, radioactive gas 

formed by the disintegration of 

the element radium; damaging to 

human lungs when inhaled.

Riparian - Areas adjacent to rivers 

and streams with a high density, 

diversity, and productivity of 

plant and animal species relative 

to nearby uplands.

Study Unit - A major hydrologic system of the United States in which 

NAWQA studies are focused. 

Study Units are geographically 

defined by a combination of 

ground- and surface-water 

features and generally encompass more than 4,000 square 

miles of land area.

Study-unit survey - Broad assessment 

of the water-quality conditions of 

the major aquifer systems of each 

Study Unit. The study-unit 

survey relies primarily on 

sampling existing wells and, 

wherever possible, on existing 

data collected by other agencies 

and programs. Typically, 20 to 30 

wells are sampled in each of three 

to five aquifer subunits.

Synoptic sites - Sites sampled during a 

short-term investigation of 

specific water-quality conditions 

during selected seasonal or 

hydrologic conditions to provide 

improved spatial resolution for 

critical water-quality conditions.

Taxon (plural taxa) - Any identifiable 

group of taxonomically related 

organisms.

Tolerant species - Those species that 

are adaptable to (tolerant of) 

human alterations to the environment and often increase in 

number when human alterations 

occur.

Unconsolidated deposit - Deposit of 

loosely bound sediment that typically fills topographically low 

areas.

Volatile organic compounds (VOCs)

Organic chemicals that have a 

high vapor pressure relative to 

their water solubility. VOCs 

include components of gasoline, 

fuel oils, and lubricants, as well 

as organic solvents, fumigants, 

some inert ingredients in pesticides, and some by-products of 

chlorine disinfection.

Water-quality criteria - Specific 

levels of water quality which, if 

reached, are expected to render a 

body of water unsuitable for its 

designated use. Commonly refers 

to water-quality criteria established by the U.S. Environmental 

Protection Agency. Water-quality 

criteria are based on specific 

levels of pollutants that would 

make the water harmful if used 

for drinking, swimming, farming, fish production, or industrial 

processes.

Yield - The mass of material or constituent transported by a river in a 

specified period of time divided 

by the drainage area of the river 

basin.
24 Water Quality in the Puget Sound Basin

REFERENCES

Black, R.W., Haggland, A.L., and Voss, F.D., 2000, 

Predicting the probability of detecting organochlorine pesticides and polychlorinated biphenyls 

in stream systems on the basis of land use in the 

Pacific Northwest, USA: Environmental Toxicology and Chemistry, v. 19, no. 4, p. 1044–1054.

Black, R.W., and MacCoy, D.E., rev. 2000, The development and evaluation of a benthic index of biological integrity for the Cedar River Watershed, 

Washington: U.S. Geological Survey WaterResources Investigations Report 99–4203, 92 p.

Black, R.W., and Silkey, M., 1998, Water-quality assessment of the Puget Sound Basin, Washington—

Summary of stream biological data through 1995: 

U.S. Geological Survey Water-Resources 

Investigations Report 97–4164, 78 p.

Bortleson, G.C., and Ebbert, J.C., 2000, Occurrence of 

pesticides in streams and ground water in the 

Puget Sound Basin, Washington and British 

Columbia, 1996–98: U.S. Geological Survey WaterResources Investigations Report 00–4118, 14 p.

CCME (Canadian Council of Ministers of the Environment), 1995, Protocol for the derivation of 

Canadian sediment quality guidelines for the 

protection of aquatic life: Winnipeg, Manitoba, 

report CCME EPC–98E, Task Group on Water 

Quality Guidelines, 38 p.

Embrey, S.S., and Inkpen, E.L., 1998, Water-quality 

assessment of the Puget Sound Basin, Washington, 

nutrient transport in rivers, 1980–93: U.S. Geological Survey Water-Resources Investigations 

Report 97–4270, 30 p.

Erwin, M.L., and Tesoriero, A.J., 1997, Predicting 

ground-water vulnerability to nitrate in the Puget 

Sound Basin: U.S. Geological Survey Fact 

Sheet 061–97, 4 p.

Hallock, Dave, Ehinger, William, and Hopkins, Brad, 

1996, River and stream ambient monitoring report 

for wateryear 1995: Washington State Department 

of Ecology publication 96–355, 29 p., 3 appendices.

Hii, Basil, Liebscher, Hugh, Mazalek, Mike, and 

Tuominen, Taina, 1999, Ground water quality and 

flow rates in the Abbotsford aquifer, British 

Columbia: Environment Canada, 36 p.

Inkpen, E.L., and Embrey, S.S., 1998, Nutrient transport 

in the major rivers and streams of the Puget Sound 

Basin, Washington: U.S. Geological Survey Fact 

Sheet 009–98, 4 p.

Inkpen, E.L., Tesoriero, A. J., Ebbert, J.C., Silva, S.R., 

and Sandstrom, M.W., 2000, Ground-water quality 

in regional, agricultural, and urban settings in the 

Puget Sound Basin, Washington and British 

Columbia, 1996–1998: U.S. Geological Survey 

Water-Resources Investigations Report 00–4100, 

66 p.

Line, J.M., ter Braak, C.J.F., and Birks, H.J.B., 1994, 

WACALIB version 3.3–A computer program to 

reconstruct environmental variables from fossil 

assemblages by weighted averaging and to derive

sample-specific errors of prediction: Journal of 

Paleolimnology, v. 10, p. 147–152.

Morgan, D.S., and Jones, J.L., 1999, Numerical model 

analysis of the effects of ground-water withdrawals on discharge to streams and springs in 

small basins typical of the Puget Sound Lowland, 

Washington: U.S. Geological Survey WaterSupply Paper 2492, 73 p.

Newell, Arthur J., Johnson, David W., and Allen, 

Laurie K., 1987, Niagara River biota contamination 

project–Fish flesh criteria for piscivorous wildlife: 

New York State Department of Environmental 

Conservation, Division of Fish and Wildlife, 

Bureau of Environmental Protection, Technical 

Report 87–3, 182 p.

Ryker, S.J., and Williamson, A.K., 1996, Pesticides in 

public supply wells in Washington State: U.S. 

Geological Survey Fact Sheet 122–96, 2 p.

Squillace, P.J., Zogorski, J.S., Wilber, W.G., and Price, 

C.V., 1996, Preliminary assessment of the 

occurrence and possible sources of MTBE in 

ground-water in the United States, 1993–1994: 

Environmental Science and Technology, v. 30,

no. 5, p. 1721–1730.

Squillace, P.J., 1999, MTBE in the Nation’s ground 

Water: U.S. Geological Survey, accessed August 18, 

2000, at URL http://sd.water.usgs.gov/nawqa/

vocns/brp-pjs-handout.html
References 25

State of Washington, 1992, Water quality standards for 

surface waters of the State of Washington: 

Olympia, Washington, Washington Administrative 

Code, chap. 173–201A, 14 p.

Staubitz, W.W., Bortleson, G.C., Semans, S.D., 

Tesoriero, A.J., and Black, R.W., 1997, Water-quality 

assessment of the Puget Sound Basin, Washington—Environmental setting and its implications 

for water quality and aquatic biota: U.S. Geological 

Survey Water-Resources Investigations 

Report 97–4013, 76 p.

Tesoriero, A.J., Liebscher, H., and Cox, S.E., 2000, 

Mechanism and rate of denitrification in an agricultural watershed—Electron and mass balance 

along ground-water flow paths: Water Resources 

Research, v. 36, no. 6, p. 1545–1559.

Tesoriero, A.J., LÖffler, F.E., and Liebscher, H., in press, 

The fate and origin of 1,2-dichloropropane in an 

unconfined shallow aquifer: Environmental 

Science and Technology.

Tesoriero, A.J., and Voss, F.D., 1997, Predicting the 

probability of elevated nitrate concentrations in the 

Puget Sound Basin—Implications for aquifer 

susceptibility and vulnerability: Ground Water, 

v. 35, no. 6, p. 1029–1039.

Tetra Tech Incorporated, 1988, Pesticides of concern in 

the Puget Sound Basin—A review of contemporary pesticide usage: Seattle, Wash., prepared for 

U.S. Environmental Protection Agency, Region 10, 

contract TC3338–32, 97 p.

U.S. Environmental Protection Agency, 1986, Ambient 

water quality criteria for bacteria, 1986: U.S. 

Environmental Protection Agency Office of Water, 

EPA 440/5–84–002, 18 p.

_____rev. February 23, 1998, Biological effects of ionizing radiation (BEIR) VI report, “The health effects 

of exposure to indoor radon”—Executive 

Summary: accessed November 9, 1999, at URL 

http://www.epa.gov/iaq/radon/beirvi.html

_____rev. October 18, 1999a, Proposed radon in drinking water rule: U.S. Environmental Protection 

Agency report EPA 815–F–99–006: accessed 

November 11, 1999, at URL http://www.epa.gov/

OGWDW/radon/fact.html

_____1999b, Achieving clean air and clean water—The 

report of the blue ribbon panel on oxygenates in 

gasoline: EPA420–R–99–021 accessed August 18, 

2000, at URL http://www.epa.gov/oms/

consumer/fuels/oxypanel/blueribb.htm

U.S. Forest Service, 1995, Pilot watershed analysis for 

the Canyon Creek watershed (draft), Mt. BakerSnoqualmie National Forest, Pacific Northwest 

region, 268 p.

U.S. Geological Survey, 1999a, Pesticides analyzed in 

NAWQA samples—Use, chemical analyses, and 

water-quality criteria: U.S. Geological Survey, 

accessed April 12, 2000, at URL 

http://water.wr.usgs.gov/pnsp/

_____1999b, The quality of our Nation’s waters— 

Nutrients and pesticides: U.S. Geological Survey 

Circular 1225, 82 p.

Voss, Frank D., Embrey, Sandra S., Ebbert, James C., 

Davis, Dale A., Frahm, Annette M., and Perry, 

George H., 1999, Pesticides detected in urban 

streams during rainstorms and relations to retail 

sales of pesticides in King County, Washington: 

U.S. Geological Survey Fact Sheet 097–99, 4 p.

Wentz, D.A., Morace, J.L., and Ryker, S.J., 1999, 

Summary—Radon in ground water from 1991 and 

1994 NAWQA study units: accessed April 26, 2000, 

at URL http://co.water.usgs.gov/trace/usgs/

summary/radon_nov99.html

Zebarth, B.J., Szeto, S.Y., Hii, B., Liebscher, H., and 

Grove, G., 1998, Groundwater contamination by 

chlorinated hydrocarbon impurities present in soil 

fumigant formulations: Water Quality Research 

Journal Canada, v. 33, no. 1, p. 31–50.
26 Water Quality in the Puget Sound Basin

Streams in agricultural areas 

Streams in urban areas

Streams and rivers draining mixed land uses 

Shallow ground water in agricultural areas

Shallow ground water in urban areas 

Major aquifers 

Detected concentration in Study Unit

Frequencies of detection, in percent. Detection frequencies 

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

column is the national frequency 

Not measured or sample size less than two

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

samples is equal to the number of wells sampled

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

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

in which a chemical was detected

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

Protection of aquatic life (applies to surface water only)

Prevention of eutrophication in streams not flowing directly into 

lakes or impoundments

No benchmark for drinking-water quality

No benchmark for protection of aquatic life

*

**

66 38

Other herbicides detected

Acetochlor (Harness Plus, Surpass) * **

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

Bromacil (Hyvar X, Urox B, Bromax) 

DCPA (Dacthal, chlorthal-dimethyl) * **

Dicamba (Banvel, Dianat, Scotts Proturf) 

Dinoseb (Dinosebe) 

Diuron (Crisuron, Karmex, Diurex) **

EPTC (Eptam, Farmarox, Alirox) * **

Fluometuron (Flo-Met, Cotoran) **

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

MCPA (Rhomene, Rhonox, Chiptox) 

Metolachlor (Dual, Pennant) 

Metribuzin (Lexone, Sencor) 

Molinate (Ordram) * **

Napropamide (Devrinol) * **

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

Oryzalin (Surflan, Dirimal) * **

Pebulate (Tillam, PEBC) * **

Pronamide (Kerb, Propyzamid) **

Terbacil (Sinbar) **

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

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

CHEMICALS IN WATER

Concentrations and detection frequencies, Puget Sound Basin, 

1996–98—Detection sensitivity varies among chemicals and, thus, 

frequencies are not directly comparable among chemicals

Lowest

25 percent

Middle

50 percent

Highest

25 percent

National water-quality benchmarks

National benchmarks include standards and guidelines related to 

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

a goal for preventing stream eutrophication due to phosphorus. Sources 

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

Council of Ministers of the Environment

|

|

|

--

This appendix is a summary of chemical concentrations 

and biological indicators assessed in the Puget Sound 

Basin. Selected results for this basin are graphically 

compared to results from as many as 36 NAWQA Study 

Units investigated from 1991 to 1998 and to national 

water-quality benchmarks for human health, aquatic life, or 

fish-eating wildlife. The chemical and biological indicators 

shown were selected on the basis of frequent detection, 

detection at concentrations above a national benchmark, 

or regulatory or scientific importance. The graphs illustrate 

how conditions associated with each land use sampled in 

the Puget Sound Basin compare to results from across the 

Nation, and how conditions compare among the several 

land uses. Graphs for chemicals show only detected

concentrations and, thus, care must be taken to evaluate

detection frequencies in addition to concentrations when 

comparing study-unit and national results. For example, 

simazine concentrations in Puget Sound Basin agricultural 

streams were similar to the national distribution, but the 

detection frequency was much higher (97 percent 

compared to 61 percent). 

CONCENTRATION, IN MICROGRAMS PER LITER

 0.0001 0.001 0.01 0.1 1 10 100 1,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Pesticides in water—Herbicides

Study-unit sample size

12

Atrazine (AAtrex, Atrex, Atred, Gesaprim) 

97 88 | | 30 47 86 | | 43 64 87 | | 42

41 40 | 22 7 30 | 27 17 18 | 30

2,4-D (Aqua-Kleen, Lawn-Keep, Weed-B-Gone) 3 15 | | 30 0 18 | | 43 0 11 | | 42

0 <1 | 22 0 1 | 27 0 <1 | 28

Deethylatrazine (Atrazine breakdown product) * ** 97 75 30 5 62 43 21 75 42

45 39 22 4 28 27 13 19 30

Prometon (Pramitol, Princep) **

70 44 | 30 98 86 | 43 31 60 | 42

0 12 | 22 4 21 | 27 3 5 | 30

Simazine (Princep, Caliber 90) 97 61 | | 30 51 77 | | 43 55 74 | | 42

36 21 | 22 4 18 | 27 3 5 | 30

Tebuthiuron (Spike, Tebusan) 63 22 | | 30 2 39 | | 43 31 32 | | 42

14 3 | 22 0 7 | 27 0 3 | 30

APPENDIX—WATER-QUALITY DATA FROM THE PUGET SOUND 

BASIN IN A NATIONAL CONTEXT

For a complete view of Puget Sound Basin data and for additional information about specific benchmarks used, visit our Web site at http://water.usgs.gov/nawqa/. 

Also visit the NAWQA Data Warehouse for access to NAWQA data sets at http://water.usgs.gov/nawqa/data. 
Water-Quality Data in a National Context 27 

CONCENTRATION, IN MICROGRAMS PER LITER

 0.0001 0.001 0.01 0.1 1 10 100 1,000 

Herbicides not detected

Acifluorfen (Blazer, Tackle 2S) **

Benfluralin (Balan, Benefin, Bonalan) * **

Bentazon (Basagran, Bentazone) **

Bromoxynil (Buctril, Brominal) * 

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

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

Clopyralid (Stinger, Lontrel, Transline) * **

Cyanazine (Bladex, Fortrol) 

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

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

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

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

Ethalfluralin (Sonalan, Curbit) * **

Fenuron (Fenulon, Fenidim) * **

MCPB (Thistrol) * **

Neburon (Neburea, Neburyl, Noruben) * **

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

Picloram (Grazon, Tordon) 

Propachlor (Ramrod, Satecid) **

Propanil (Stam, Stampede, Wham) * **

Propham (Tuberite) **

2,4,5-T **

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

Thiobencarb (Bolero, Saturn, Benthiocarb) * **

Triallate (Far-Go, Avadex BW, Tri-allate) * 

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Pesticides in water—Insecticides

Study-unit sample size

Volatile organic compounds (VOCs) in ground water

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

Study-unit frequency of detection, in percent

National frequency of detection in percent Study-unit sample size

CONCENTRATION, IN MICROGRAMS PER LITER

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

Chlorpyrifos (Brodan, Dursban, Lorsban) 

0 18 | | 30 7 37 | | 42 0 20 | | 42

0 1 | 22 0 1 | 27 0 <1 | 30

Diazinon (Basudin, Diazatol, Neocidol, Knox Out) 43 16 | | 30 84 70 | | 43 14 39 | | 42

0 <1 | 22 0 2 | 27 0 2 | 30

gamma-HCH (Lindane, gamma-BHC) 0 1 | | 30 2 1 | | 42 0 4 | | 42

0 <1 | 22

0 <1 | 30

Other insecticides detected 

Carbaryl (Carbamine, Denapon, Sevin) 

Carbofuran (Furadan, Curaterr, Yaltox) 

Ethoprop (Mocap, Ethoprophos) * **

Malathion (Malathion) 

Oxamyl (Vydate L, Pratt) **

Propargite (Comite, Omite, Ornamite) * **

Insecticides not detected

Aldicarb (Temik, Ambush, Pounce) 

Aldicarb sulfone (Standak, aldoxycarb) 

Aldicarb sulfoxide (Aldicarb breakdown product) 

Azinphos-methyl (Guthion, Gusathion M) * 

p,p'-DDE 

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

Disulfoton (Disyston, Di-Syston) **

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

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

3-Hydroxycarbofuran (Carbofuran breakdown product) * **

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

Methomyl (Lanox, Lannate, Acinate) **

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

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

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

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

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

Terbufos (Contraven, Counter, Pilarfox) **

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

9 1 | 22

0 <1 | 30

1,2-Dichloropropane (Propylene dichloride) 

77 13 | 22 0 1 | 27 0 1 | 30

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

6 7 | 18 63 18 | 27 0 3 | 30

Ethylbenzene (Phenylethane) 

0 4 | 18 56 13 | 27 0 1 | 30

Methyl tert-butyl ether (MTBE) 

18 4 | 22 0 16 | 27 0 6 | 30

Methylbenzene (Toluene) 

50 36 | 18 44 30 | 27 3 11 | 30

1,1,1-Trichloroethane (Methylchloroform) 

18 5 | 22 52 22 | 27 17 8 | 30

1,2,4-Trimethylbenzene (Pseudocumene) * 

41 19 17 22 18 27 67 19 30

Other VOCs detected

Benzene 

Bromodichloromethane (Dichlorobromomethane) 

Carbon disulfide * 

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

Chlorobenzene (Monochlorobenzene) 

Chlorodibromomethane (Dibromochloromethane) 

Chloromethane (Methyl chloride) 
28 Water Quality in the Puget Sound Basin

CONCENTRATION, IN MILLIGRAMS PER LITER

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

CONCENTRATION, IN MILLIGRAMS PER LITER

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

Dissolved solids in water

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Nutrients in water

Study-unit frequency of detection, in percent

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

Study-unit sample size

Dichlorodifluoromethane (CFC 12, Freon 12) 

1,2-Dichloroethane (Ethylene dichloride) 

Dichloromethane (Methylene chloride) 

1,3-Dichloropropane (Trimethylene dichloride) * 

1,2-Dimethylbenzene (o-Xylene)

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

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

Iodomethane (Methyl iodide) * 

Isopropylbenzene (Cumene) * 

2-Propanone (Acetone) * 

n-Propylbenzene (Isocumene) * 

Tetrachloroethene (Perchloroethene) 

Trichloroethene (TCE)

Trichlorofluoromethane (CFC 11, Freon 11) 

Trichloromethane (Chloroform) 

1,2,3-Trichloropropane (Allyl trichloride) 

1,2,3-Trimethylbenzene (Hemimellitene) * 

1,3,5-Trimethylbenzene (Mesitylene) *

VOCs not detected

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

Bromobenzene (Phenyl bromide) * 

Bromochloromethane (Methylene chlorobromide) 

Bromoethene (Vinyl bromide) * 

Bromomethane (Methyl bromide) 

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

n-Butylbenzene (1-Phenylbutane) * 

sec-Butylbenzene * 

tert-Butylbenzene * 

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

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

Chloroethane (Ethyl chloride) * 

Chloroethene (Vinyl chloride) 

1,2-Dibromoethane (Ethylene dibromide, EDB) 

Dibromomethane (Methylene dibromide) * 

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

1,2-Dichlorobenzene (o-Dichlorobenzene) 

1,3-Dichlorobenzene (m-Dichlorobenzene) 

1,4-Dichlorobenzene (p-Dichlorobenzene) 

1,1-Dichloroethane (Ethylidene dichloride) * 

1,1-Dichloroethene (Vinylidene chloride) 

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

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

2,2-Dichloropropane * 

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

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

1,1-Dichloropropene * 

Diethyl ether (Ethyl ether) * 

Diisopropyl ether (Diisopropylether (DIPE)) * 

Ethenylbenzene (Styrene) 

Ethyl methacrylate* 

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

Hexachlorobutadiene 

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

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

p-Isopropyltoluene (p-Cymene) * 

Methyl acrylonitrile * 

Methyl-2-methacrylate (Methyl methacrylate) * 

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

Methyl-2-propenoate (Methyl acrylate) * 

Naphthalene 

2-Propenenitrile (Acrylonitrile) 

1,1,2,2-Tetrachloroethane * 

1,1,1,2-Tetrachloroethane 

Tetrachloromethane (Carbon tetrachloride) 

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

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

Tribromomethane (Bromoform) 

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

1,2,4-Trichlorobenzene 

1,2,3-Trichlorobenzene * 

Trace elements in ground water

Study-unit frequency of detection, in percent

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

CONCENTRATION, IN PICOCURIES PER LITER

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

Radon-222 

-- 99 | 0 100 100 | 16 100 97 | 30

Ammonia, as N * **

87 84 75 70 86 117 55 75 153

29 78 21 41 71 27 70 70 30

Dissolved ammonia plus organic nitrogen, as N * ** 79 78 75 72 74 117 13 62 153

19 28 21 7 30 27 7 24 30

Dissolved nitrite plus nitrate, as N ** 100 95 | 75 100 97 | 117 97 91 | 153

95 81 | 21 93 74 | 27 93 71 | 30

Orthophosphate, as P * **

75 79 75 93 72 117 52 74 153

52 59 21 81 52 27 93 61 30

Total phosphorus, as P * ** 96 92 | 75 96 90 | 117 80 88 | 153

Dissolved solids * ** 100 100 75 100 100 117 100 100 152

100 100 22 100 100 27 100 100 30
Water-Quality Data in a National Context 29 

Fish tissue from streams in agricultural areas

Fish tissue from streams in urban areas

Fish tissue from streams draining mixed land uses

Sediment from streams in agricultural areas 

Sediment from streams in urban areas 

Sediment from streams draining mixed land uses

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

Protection of aquatic life (applies to bed sediment)

No benchmark for protection of fish-eating wildlife

No benchmark for protection of aquatic life

|

|

**

CHEMICALS IN FISH TISSUE

AND BED SEDIMENT

Concentrations and detection frequencies, Puget Sound Basin, 

1996–98—Detection sensitivity varies among chemicals and, thus, 

frequencies are not directly comparable among chemicals. Study-unit 

frequencies of detection are based on small sample sizes; the 

applicable sample size is specified in each graph

Lowest

25 percent

Middle

50 percent

Highest

25 percent

National benchmarks for fish tissue and bed sediment

National benchmarks include standards and guidelines related to 

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

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

other Federal and State agencies, and the Canadian Council of 

Ministers of the Environment

*

Other organochlorines detected

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

Heptachlor epoxide (Heptachlor breakdown product) * 

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

Hexachlorobenzene (HCB) **

Pentachloroanisole (PCA) * **

Organochlorines not detected

Chloroneb (Chloronebe, Demosan) * **

DCPA (Dacthal, chlorthal-dimethyl) * **

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

Endrin (Endrine) 

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

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

Isodrin (Isodrine, Compound 711) * **

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

o,p'-Methoxychlor * **

Mirex (Dechlorane) **

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

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

Toxaphene (Camphechlor, Hercules 3956) * **

CONCENTRATION, IN MICROGRAMS PER KILOGRAM

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

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

CONCENTRATION, IN MICROGRAMS PER KILOGRAM

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

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

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

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

in which a chemical was detected

Detected concentration in Study Unit

Frequencies of detection, in percent. Detection frequencies 

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

column is the national frequency

Not measured or sample size less than two

Study-unit sample size

66 38

--

12

Organochlorines in fish tissue (whole body)

and bed sediment

Study-unit frequency of detection, in percent

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

Study-unit frequency of detection, in percent

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

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

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

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

Other trace elements detected

Chromium

Trace elements not detected

Arsenic 

Cadmium 

Lead 

Selenium 

Uranium 

Zinc 

Total Chlordane (sum of 5 chlordanes) 

33 38 | 3 71 75 | 7 0 56 | 4

33 9 | 3 12 57 | 8 0 11 | 4

p,p'-DDE * **

67 90 3 71 94 7 0 92 4

33 48 3 12 62 8 0 39 4

o,p'+p,p'-DDE (sum of o,p'-DDE and p,p'-DDE) * 67 90 3 71 94 7 0 92 4

33 48 | 3 12 62 | 8 0 39 | 4

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

33 31 3 29 53 7 0 29 4

0 19 | 3 12 38 | 8 0 11 | 4

Total DDT (sum of 6 DDTs) **

67 90 | 3 71 94 | 7 0 93 | 4

33 49 3 12 66 8 0 41 4

Dieldrin (Panoram D-31, Octalox) * 

33 53 3 57 42 7 0 38 4

0 13 | 3 12 30 | 8 0 9 | 4

Dieldrin+aldrin (sum of dieldrin and aldrin) ** 33 52 | 3 57 42 | 7 0 38 | 4

0 13 3 12 29 8 0 9 4

Total PCB 1

0 38 | 3 43 81 | 7 0 66 | 4

0 2 | 3 0 21 | 8 0 9 | 4
30 Water Quality in the Puget Sound Basin

Other SVOCs detected

Acenaphthylene 

Acridine **

Anthracene 

Azobenzene **

Benzo[b]fluoranthene **

Benzo[ghi]perylene **

Benzo[k]fluoranthene **

2,2-Biquinoline **

Butylbenzylphthalate **

p-Cresol **

Di-n-butylphthalate **

Di-n-octylphthalate **

Diethylphthalate **

1,2-Dimethylnaphthalene **

1,6-Dimethylnaphthalene **

3,5-Dimethylphenol **

Dimethylphthalate **

9H-Fluorene (Fluorene) 

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

Isoquinoline **

1-Methyl-9H-fluorene **

2-Methylanthracene **

4,5-Methylenephenanthrene **

1-Methylphenanthrene **

1-Methylpyrene **

Naphthalene 

Phenanthridine **

2,3,6-Trimethylnaphthalene **

SVOCs not detected

C8-Alkylphenol **

Benzo[c]cinnoline **

4-Bromophenyl-phenylether **

4-Chloro-3-methylphenol **

bis(2-Chloroethoxy)methane **

CONCENTRATION, IN MICROGRAMS PER KILOGRAM, DRY WEIGHT

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

CONCENTRATION, IN MICROGRAMS PER KILOGRAM, DRY WEIGHT

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

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Semivolatile organic compounds (SVOCs)

in bed sediment

Study-unit sample size

Study-unit sample size

Acenaphthene 

33 10 | 3 50 54 | 8 0 27 | 4

Anthraquinone **

33 21 3 88 83 8 25 39 4

Benz[a]anthracene 

67 44 | 3 100 94 | 8 75 62 | 4

Benzo[a]pyrene 

33 40 | 3 100 92 | 8 25 59 | 4

9H-Carbazole **

33 19 3 100 76 8 25 33 4

Chrysene 

100 50 | 3 100 94 | 8 75 67 | 4

Dibenz[a,h]anthracene 

0 8 | 3 50 68 | 8 0 23 | 4

Dibenzothiophene **

33 12 3 88 64 8 25 30 4

2,6-Dimethylnaphthalene **

100 65 3 50 74 8 75 77 4

bis(2-Ethylhexyl)phthalate **

100 91 3 100 99 8 75 95 4

Fluoranthene 

100 66 | 3 100 97 | 8 75 78 | 4

N-Nitrosodiphenylamine **

33 2 3 25 10 8 0 4 4

Phenanthrene 

100 50 | 3 100 93 | 8 75 66 | 4

Phenol **

100 81 3 100 82 8 75 80 4

Pyrene 

100 64 | 3 100 95 | 8 75 76 | 4
Water-Quality Data in a National Context 31 

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Biological indicator value, Puget Sound Basin, by land use, 

1996–98

Biological status assessed at a site

National ranges of biological indicators, in 16 NAWQA Study 

Units, 1994–98

Streams in undeveloped areas

Streams in agricultural areas

Streams in urban areas

Streams in mixed-land-use areas

75th percentile

25th percentile

BIOLOGICAL INDICATORS

Higher national scores suggest habitat disturbance, water-quality 

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

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

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

changes in the percentage of certain algae in response to 

increasing siltation, and it often correlates with higher nutrient 

concentrations in some regions. Invertebrate status averages 11 

metrics that summarize changes in richness, tolerance, trophic 

conditions, and dominance associated with water-quality 

degradation. Fish status sums the scores of four fish metrics 

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

individuals with external anomalies) that increase in association 

with water-quality degradation

 0 10 20 30 40 50 60 70 80 90 100

CONCENTRATION, IN MICROGRAMS PER GRAM

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

 0.01 0.1 1 10 100 10,000 1,000 

CONCENTRATION, IN MICROGRAMS PER GRAM

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

 0.01 0.1 1 10 100 10,000 1,000 

Study-unit frequency of detection, in percent

National frequency of detection, in percent

Trace elements in fish tissue (livers) and 

bed sediment

Study-unit sample size

Study-unit sample size

2-Chloronaphthalene **

2-Chlorophenol **

4-Chlorophenyl-phenylether **

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

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

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

2,4-Dinitrotoluene **

Isophorone **

Nitrobenzene **

N-Nitrosodi-n-propylamine **

Pentachloronitrobenzene **

Quinoline **

1,2,4-Trichlorobenzene **

 Algal status indicator

Undeveloped

Agricultural

Urban

Mixed

 Invertebrate status indicator

Undeveloped

Agricultural

Urban

Mixed

Undeveloped

Agricultural

Urban

Mixed

 0 5 10 15 20

 Fish status indicator

Arsenic * 

-- 56 0 -- 38 0 -- 76 0

100 99 | 3 100 98 | 8 75 97 | 4

Cadmium * 

-- 77 0 -- 72 0 -- 95 0

100 98 | 3 100 100 | 8 100 98 | 4

Chromium * -- 62 0 -- 72 0 -- 54 0

100 100 | 3 100 99 | 8 100 100 | 4

Copper * -- 100 0 -- 100 0 -- 100 0

100 100 | 3 100 99 | 8 100 100 | 4

Lead * 

-- 11 0 -- 41 0 -- 41 0

100 100 | 3 100 100 | 8 50 99 | 4

Mercury * 

-- 71 0 -- 59 0 -- 80 0

100 82 | 3 100 97 | 8 100 93 | 4

Nickel * **

-- 42 0 -- 44 0 -- 50 0

100 100 3 100 100 8 100 100 4

Selenium * -- 99 0 -- 100 0 -- 99 0

100 100 | 3 100 100 | 8 100 100 | 4

Zinc * 

-- 100 0 -- 100 0 -- 100 0

100 100 | 3 100 99 | 8 100 100 | 4
Coordination with agencies and organizations in the Puget Sound Basin was integral to the success of this waterquality assessment. We thank those who served as members of our liaison committee. 

Federal Agencies

Bureau of Indian Affairs

National Marine Fisheries Service

National Park Service

Northwest Indian Fisheries Commission

U.S. Army Corps of Engineers

U.S. Environmental Protection Agency

U.S. Fish and Wildlife Service

U.S. Forest Service

Canadian Agencies

British Columbia Ministry of 

 Environment

Environment Canada

State Agencies

Puget Sound Water Quality Action

 Team

Washington State Department of

 Agriculture

Washington State Department of

 Ecology

Washington State Department of

 Fish and Wildlife

Native American Tribes and

Nations

Lummi Tribe

Muckleshoot Tribe

Nooksack Tribe

Puyallup Tribe

Skokomish Tribe

Universities

University of Washington

Washington State University

Other Public and Private

Organizations

Adopt a Stream Foundation

People for Puget Sound

Thornton Creek Project

Washington Environmental Council

Washington Toxics Coalition

We thank the following individuals for contributing to this effort. 

• Gil Bortleson (USGS, Washington District) participated in the design of the study and authored several reports.

• Dale Davis (Washington State Department of Ecology) was a partner and coauthor in the study of pesticides in streams.

• Sue Davis (Thurston County), Mindy Fohn (City of Bremerton), Keith Grellner (Kitsap County), Ray Hanowell (Pierce County), 

Joe Joy (Washington State Department of Ecology), and Ginny Stern (Washington State Department of Health) helped in the design of 

the microbiological studies.

• Annette Frahm and George Perry (King County) provided sales data for pesticides, conducted toxicity tests, and coauthored a fact sheet 

about pesticides in urban streams.

• Kathleen Greene, Joseph Gilbert, Gary Holloway, Brett Smith, and Greg Justin (USGS, Washington District) played a major role in the 

collection and compilation of water-quality and streamflow data.

• Emily Inkpen (USGS, Washington District) collected and compiled water-quality data and authored a number of reports.

• Dr. James Karr (University of Washington) provided advice on the analysis of macroinvertebrate data.

• Moon Kim, Raegan Huffman, Stephanie Leisle, Mark Munn, Steve Sumioka, and Ann Vanderpool (USGS, Washington District); 

Steve Goodbred and Terry Short (USGS, Western Region); Mariabeth Silkey and Michael Hummling (University of Washington); and 

Dave Serdar and Art Johnson (Washington State Department of Ecology) provided field support and assisted in data collection.

• Hugh Liebscher and Basil Hii (Environment Canada) provided water level and chemistry data for wells in Canada.

• Dorene MacCoy (USGS, Idaho District) helped collect and interpret biological data and helped produce a number of reports.

• Rob Plotnikoff (Washington State Department of Ecology) provided macroinvertebrate and habitat data.

• Dr. Mark Sobsey, Fu-Chih Hsu, and Douglas Wait (University of North Carolina, Chapel Hill) provided technical assistance and 

laboratory analyses for the microbiological study.

• Ward Staubitz (USGS, Virginia District), project chief until April 1997, played a major role in the design of the study.

• Ian Waite and Dennis Wentz (USGS, Oregon District) provided fish tissue data from the Willamette Basin, Oregon.

• Frank Voss (USGS, Washington District) managed the project data base and produced a number of reports.

Appreciation is extended to those individuals who reviewed this report or helped prepare it.

Joe Joy, Washington State Department of Ecology Dennis Wentz, USGS, Oregon District

Cindy Moore, Washington State Department of Agriculture Ginger Renslow, Editor, USGS, Washington District

Richard Ramsey, Staff to the Washington State Environmental Robert Crist, Illustrator, USGS, Washington District

 Quality and Water Resources Committee

Washington State Department of

 Health

Washington State Department of

 Natural Resources

Washington State Department of

 Transportation

Local Agencies

City of Auburn

City of Bremerton

City of Lacey

City of Olympia

City of Renton

City of Seattle

City of Tacoma

King County

Kitsap County

Pierce County

Seattle Public Utilities

Snohomish County

Tacoma-Pierce County Health

 Department

Thurston County

Whatcom County
Ebbert and others— Water Quality in the Puget Sound Basin

U.S. Geological Survey Circular 1216

National Water-Quality Assessment (NAWQA) Program

Puget Sound Basin

NAWQA

Bellingham

Everett

Seattle

Tacoma

Olympia

Strait of Juan de Fuca

PUGET SOUND

WASHINGTON

BRITISH

COLUMBIA