Only two of the 23 pesticides detected
in streams—malathion and pentachlorophe-
nol—have aquatic-life criteria established
by the State or USEPA; neither pesticide
exceeded these criteria. Aquatic-life crite-
tia are established for some individual
compounds, but no criteria exist for combi-
nations of pesticides, and the effects from
these combinations are not well under-
stood, The data indicate that, in some of
the streams sampled, multiple pesticides
occur. For example, a total of 18 pesticides
was detected in samples from Mercer
Creek. Individual concentrations were gen-
erally small; however, the combined
effects of all these pesticides may have
more or less impact on aquatic organisms
than would be expected from individual
compounds.

Although banned organochlorine pest-
icides were detected in streambed sedi-
ments at small concentrations, they are
probably not acutely affecting aquatic
organisms. However, these small concentra-
tions of pesticides readily accumulate in
fatty tissues of organisms that are exposed
to them. For example, fish exposed to sedi-
ments containing organochlorine pesticides

could accumulate pesticide concentrations
high enough to reduce spawning success,
In addition, many of the persistent orga-
nochlorine compounds have recently been
linked to reproductive problems in aquatic
species, birds, and mammals (Colborn and
others, 1996).

Future Pesticide Monitoring

These results indicate that pesticides do
occur at generally small concentrations not
exceeding aquatic life or human health crite-
tia in small streams and streambed
sediments within the Puget Sound Basin.
Pesticide use and occurrence are greatest in
the urban areas of the basin. Additional pes-
ticide monitoring will be required to
evaluate trends over time and to assess the
occurrence and distribution of currently
used and new pesticides. Further pesticide
sampling will be conducted by the USGS
and Ecology to better evaluate the occur-
rence of pesticides with respect to land use,
seasonal variations, and storm runoff. The
USGS Puget Sound National Water Quality
Assessment (NAWQA) project will conduct
intensive seasonal and storm sampling of

two large rivers and two small streams in the
basin to achieve the following objectives:

* evaluate pesticide occurrence in large riv-
ers and small streams draining agricul-
tural and urban areas,

* assess seasonal and storm-related varia-
tions of pesticide concentrations, and

* calculate estimated loads of pesticides
from selected streams draining different
land uses.

As part of the Washington State Pesti-
cide Monitoring Program, Ecology will
continue to assess pesticide contamination
in streams throughout the basin, including
cooperative sampling efforts with the
USGS. The goal of this monitoring program
is to characterize pesticides geographically
and over time in water, bed sediments, and
aquatic organisms, which will provide infor-
mation to improve pesticide management in
the state and ultimately help reduce the risk
of pesticide exposure that can result in
adverse effects on aquatic organisms and
human health.

References

1, Canadian Council of Resource and Environ-
ment Ministers, 1987, Canadian water quality
guidelines: Canadian Council of Resource
and Environment Ministers, Ottawa, Ontario,
Canada, 365 p.

2. Colborn, Theo, Dumanoski, Dianne, and Myers,
J.P, 1996, Our stolen future: Dutton, New
York, 306 p.

3. Davis, D.A., 1993, Washington State pesticide
monitoring program--reconnaissance sam-
pling of surface waters (1992): Olympia,

Wash Washington State Department of Ecol-
ogy, 38 p.

4. Davis, Dale, 1996, Washington State pesticide
monitoring program 1994 surface water sam-
pling report: Olympia, Wash., Washington
State Department of Ecology, publication no.
96-305, 19 p.

5. Davis, Dale, 1996, Washington State Depart-
ment of Ecology, written communication.

6. Davis, Dale, and Johnson, Art, 1994a, Washing-
ton State pesticide monitoring program
reconnaissance sampling of fish tissue and
sediments (1992): Olympia, Wash., Washing-
ton State Department of Ecology, publication
no. 94-194, 33 p.

7. Davis, Dale, and Johnson, Art, 1994b, Washing-
ton State pesticide monitoring program 1993
surface water sampling report: Olympia,
Wash., Washington State Department of Ecol-
ogy, publication no. 94-164, 21 p.

8, Farm Chemicals Handbook, 1994, Farm Chemi-
cals Handbook: Meister Publishing Co., Wil-
loughby, Ohio, misc. pagination.

June, 1997

9. Mayer, J.R., and Elkins, N.R., 1990, Potential
for agricultural pesticide runoff to a Puget
Sound estuary~Padilla Bay, Washington:
Bulletin of Environmental Contamination
and Toxicology, v. 45, p. 215-222.

10. National Academy of Sciences, 1973, Water
quality criteria, 1972, A report of the com-
mittee on water quality criteria, Environ-
mental Studies Board, National Academy
of Sciences, National Academy of Engi-
neering, Washington, D.C., 594 p.

11. Norris, L. and Dost, F. 1991, Proposed sur-
face water quality criteria for selected pes-
ticides used for forest management and
management of forest tree seedling and
christmas tree plantations in Oregon and
Washington (draft): Oregon State Univer-
sity, Corvallis, Oregon, 39 p.

12. Nowell, L-H., and Resek, E.A., 1994, Sum-
mary of national standards and guidelines
for pesticides in water, bed sediment, and
aquatic organisms and their application to
water-quality assessments: U.S. Geological
Survey Open-File Report 94-44, 115 p.

13. PTI Environmental Services, 1991, 1990
Puget Sound pesticide reconnaissance sur-
vey: Bellevue, Wash,, prepared for U.S.
Environmental Protection Agency Region
10, contract 68D80085, 39 p.

14, State of Washington, 1992, Water quality
standards for surface waters in State of
Washington: State of Washington, Chapter
173-201WAC, Olympia, WA, 14 p.

#8 U.S. GOVERNMENT PRINTING OFFICE: 2000 — 573-280 / 20027 Region No. 8

15, Tetra Tech Incorporated, 1988, Pesticides of
concern in the Puget Sound Basin—a
review of contemporary pesticide usage:
Seattle, Wash., prepared for U.S, Environ-
mental _ Protection Agency, Region 10,
contract. TC3338-32, 97 p.

16. U.S. Environmental Protection Agency, 1986,
Quality criteria for water; U.S. Environmen-
tal Protection Agency, Office of Regulations
and Standards, Washington, unpaginated

[ ‘The National Water Quality ]
Assessment (NAWQA) Program of
the U.S. Geological Survey is designed
to describe the current water-quality
conditions for a large part of
the Nation's ground and surface water,
to describe how water quality is changing
‘over time, and to improve our
understanding of the national and human
factors that affect our water quality.

U.S. Geological Survey Fact Sheet 067-97
by Gilbert C. Bortleson and Dale A. Davis
Tustrations: Donna R. Tarver, USGS, WA District
Banner: Karen A. Lonsdorf. USGS, WI District
For further information, contact:
Project Chief,
US. Geological Survey
Puget Sound Basin NAWQA
1201 Pacific Ave. Suite 600
Tacoma, WA’ 98402
(253) 593-6510
E-mail:nawqa_puget_wa@usgs.gov
World Wide Web:
htp://wwwdwatcm.wr.usgs.gov/ps.nawga.btml



Pesticides in Selected Small Streams in the Puget Sound Basin, 1987-1995

by Gilbert C. Bortleson, U.S. Geological Survey, and Dale A. Davis, Washington State Department of Ecology

\

E

Pesticides in the aquatic environment are a concern because of possible effects on fish, wildlife,
and human health. From 1987 to 1995, Washington State Department of Ecology (Ecology) and
the U.S. Environmental Protection Agency (USEPA) conducted studies to assess the occurrence
of pesticides in streams and streambed sediments in the Puget Sound Basin. Most samples were
collected from small streams and sloughs (none were sources of drinking water) during the spring
and summer, when pesticides were most likely to have been recently applied and therefore be
detected. This fact sheet summarizes data from several of these studies.

CANADA

re we ww
[Ronsanaoun | |
or) \ Fishtrap Crook (3,7)
Washington

——Big indian Stough (9,33)
Tite ndan Seagh

Base Irom U.S. Geological Survey digital data, 1:2,000,000, 1972 Albers Equal-Area Conic Projection

Land use and location of small streams sampled for pesticides
(Numbers refer to sources of data. See References.)

Conway Siough (13)
= Big Ditch Siough (13)

Significant Findings

The most commonly detected pesticides in
streams were among the most heavily used
in the basin. The most frequently detected
pesticide in streams was 2,4-D, the most
heavily used herbicide in the Puget Sound
Basin. Other commonly detected and heavily
used pesticides were the herbicide dicamba
and the insecticide diazinon.

Pesticide concentrations generally were
small. None of the detected pesticides in
streams exceeded existing State or Federal
freshwater aquatic life criteria; however, cri-
teria have been established for only two of the
pesticides detected. Diazinon, mevinphos,
malathion, and diuron were found in streams
exceeding maximum concentrations recom-
mended by the National Academy of Sciences
for the protection of aquatic life (National
Academy of Sciences, 1973). None of the
detected pesticides exceeded the USEPA's
standards or guidelines for drinking water.

Pesticides that are currently banned in the
U. S. were found in streambed sediments.
The pesticide most commonly found in stre-
ambed sediments was the fungicide PCP
(pentachlorophenol); the insecticides DDT
and chlordane were also detected. These com-
pounds are organochlorine pesticides that
were heavily used in the past, but are now
banned from use in the U. S. However, detec-
tion of organochlorine pesticides is common
in sediments across the U. S. because these
compounds degrade slowly and bind strongly
to soil particles. No State freshwater sedi-
ment-quality criteria exist for these com-
pounds, but the USEPA has proposed
guidelines for DDT and chlordane to protect
benthic organisms.


Number and Type of Pesticides Detected
—____Inwater_In bed sediments

collected samples from small sloughs in agri-
cultural areas in the northerm part of the
basin. Although these studies varied in
design and analytical methods used, the data
generally characterize the occurrence of pesti-
cides in small streams in the Puget Sound

Herbicide 7 2
Insecticide 5 4

Fungicide 1 1

Degradation products of DDT _0 2 as
Total 2B 9 Basin.

Studies Reviewed

A USEPA inventory in 1988 of contempo-
rary pesticide usage in the Puget Sound Basin
(Tetra Tech, 1988) indicates that approxi-
mately 2.8 million pounds of pesticides are
used annually (the table on the facing page
lists 18 pesticides that are estimated to be
applied in amounts greater than 20,000
pounds/year in the basin.) Following this
inventory, the USEPA conducted a reconnais-
sance study of five small streams draining
various land uses (PTI Environmental Ser-
vices, 1991). Since 1992, Ecology has
collected water or bed-sediment samples
from nine streams, Mayer and Elkins (1990)
from Western Washington State University

Pesticides Detected in Small
Streams

Herbicides were detected more frequently
than insecticides. Seventeen of 23 pesticides
detected in water were herbicides. The com-
monly used herbicide 2,4-D was found in 12
of 13 streams. Other herbicides—bromacil,
DCPA, dicamba, dichlobenil, diuron, and
MCPP—were found at five or more streams.
The insecticide diazinon was found in six
streams, and three other — insecticides—
malathion, mevinphos, and propoxur—were
detected in one or two streams. In general,
more pesticides were detected in urban
streams than in agricultural streams. Eigh-
teen pesticides were detected in Mercer
Creek, an urban stream, whereas 13 pesticide

detections in Joe Leary Slough were the great-
est number of pesticides found in an
agricultural stream. Seven pesticides were
detected exclusively in urban streams, five
were found only in agricultural streams, and
11 were common to both. Few of these pesti-
cides are used exclusively in urban or
agricultural areas, Their occurrences probably
reflect local application practices.

The graph below shows that 23 pesticides
were detected at mostly small concentrations
either as estimated or quantifiable values.

Pesticides Detected in Streambed
Sediments

Of the total number of compounds
detected in streambed sediments, most were
insecticides or insecticide degradation prod-
ucts. Six of the nine pesticides detected in
streambed sediments were insecticides (or
their degradation products), two were herbi-
cides, and one a fungicide. The most
frequently detected compounds in sediments.
found in both urban and agricultural streams,
were PCP, detected in five streams, and DDT

7
i ici i Range below the quantitation limit
Concentrations of pesticides detected in water —, Rarer ne guanine ove quantitation limit
© Pesticide detected at concentration below quantitation limit
1 Recommended maximum concentration for aquatic lite
Pesticide Aquatic Lite Criteria (ppb) 1 USEPA or State chronic aquatic life criterion
E) IRMC, Recome 5
(Example trade name”) mun cone, = Concentration, in parts per billion (ppb)
Insecticide Acute Chronic = RMC 9-004 ____, 001 pe re re f°
TS Dichloropropene a = =
Diazinon - - 30.009 CREDO ONC Ce
Malathion 40.1 30.008 1 RCO!
Mevinphos (Phosdrin) = ~ 30,002 1 aes
Propoxur (Baygon) - = gs 2
Herbicide
24D 1200 S12 3 OS DOO Koc omens ene o 1
‘Atrazine (AAtex) 4 4 ooo oe |
Bentazon (Basagran) . . . Ea
Bromacil (Hyvar) ~ - OOS! °
Chlorpropham " ~ - = .
DCPA (Dacthal) ~ - - 2 oo ae.0
Dicamba (Banvel) $300 539 *10 ad eee '
Dichlobenil (Casoron) - - 337 OD Oa Doo n
Diuron (Karmex) 7 . 16 — °
EPTC (Eptam) = 2 e ——F
Glyphosate (Roundup) 5300 530 65 n
MCPA (Weedon) - - 26 OND!
MCPP (Mecopar) = = = SHNISIOONONONe -
Metribuzin (Sencor) — Pa % ou} i
Prometon (Pramitol) “os o 6 o
Simazine (Princep) 502 S10 oOo oe '
Trichlopyr (Garlon) 35,600 5569 = 2 000 soe :
Fungicide
Pentachlorophenol (Penta) 47899 47.813 5 | wee ° 1 1
— = caren
0.001 0.01 10 Yoo
ii the ated
mt hee gp ah sgn eat pe wie qin wan ei
2-Use of trade names is for descriptive purposes and does not imply endorsement by the U.S. Geological Survey or the Department of Ecology.
'3-National Academy of Sciences, 1973
|4-U.S. Environmental Protection Agency, 1986
S-Norris and Dost, 199
(6-Canadian Council of Resource and Environment Ministers, 1987
[7-State of Washington, 1992
(8-Criteria are pH ndent, values shown calculated at a pH of 7.8



and/or its degradation products DDD and
DDE, detected in three streams. Chlordane
was also detected in sediments. DDT, PCP,
and chlordane are currently banned from use
in the U. S., but were heavily used in the
past. Because of their slow degradation
rates, these pesticides are likely to be present
in sediments for many years. DDT was
used as an insecticide; PCP was used prima-
Tily as a fungicide, but also as an insecticide
and herbicide. Other pesticides found in bed
sediments from at least two streams were
the herbicides dichlobenil and dicamba. The
insecticides chlordane, diazinon, and
endosulfan were identified in one stream
each. The graph below shows that nine
compounds were detected at concentrations
either as estimated or quantifiable values.
Pesticides in bed sediments do not have any
State freshwater sediment-quality criteria,
but USEPA guidelines to protect benthic
organisms are proposed for DDT, chlordane,
and endosulfan in bed sediments (Nowell
and Resek, 1994). These guidelines, which
are based on the amount of organic carbon in
the sediments, do not apply to concentrations
shown in the graph.

Factors Influenci
Concentrations an

Pesticide
Detections

Detections and concentrations of pesti-
cides in streams are influenced by many
factors, including the amount of pesticide
used, the environmental persistence of the
pesticide, and the analytical methods used.

In the Puget Sound Basin, the most com-
monly detected pesticides were among the
most heavily applied. Eleven of the 18 pes-
ticides that are most heavily used were
detected in water or bed sediments (see table
above). Application practices in urban and
agricultural areas are important in determin-
ing whether pesticides reach streams.
Pesticides are used around urban house-
holds, businesses, and parks, and
application practices of urban users differ
widely. Urban use of pesticides (about 1.1
million pounds/year) was more than three
times greater than agricultural use (Tetra
Tech, 1988). This may explain in part why

Concentrations of pesticides detected in bed sediment
Range below the quantitation limit”
@ Pesticide detected at concentration above quantitation limit
© Pesticide detected at concentration below quantitation limit
1D Pesticide detection. No quantitation limit given by investigators

Pesticide or Degradation Product Concentration, in parts per million (ppm)
(Example trade name”)

Insecticide 0.901 9. 01 R41 2: 2 190

44-DDT ° oO

Chlordane (many) o

Diazinon o

Endosulfan (Thiodan) LI

Herbicide

‘Dicamba (Banvel) . .

Dichlobenil (Casoron) 2 2°

Fungicide

Pen mhenol (Peata)] Oe Ey

Degradation Product

Fa-DDD oo 0 ©

44°-DDE 2 20°

T " r 7 7 r
0,001 0.01 07 100

4-The quantitation limits the smallest cies‘ wet apes cn be neni and pee it thot qualification

aas an estimated concentration. Sce sources of data in References for tabulated data of estima

2-Use of wade names is for descriptive purposes and docs 01 imply endorsement bythe US. Oeolopical Surveyor the
Department of Ecology.

the number of different pesticides found in
urban streams is greater than in agricultural
streams.

Chemical characteristics of pesticides are
a major factor in environmental persistence.
The majority of currently used pesticides
break down relatively rapidly after applica-
tion. Consequently, pesticide detections
occur most frequently in the weeks follow-
ing periods of heaviest pesticide application,
which usually are in spring and early sum-
mer in the basin. Detections of pesticides
have also increased over time as analytical
methods improve and smaller concentrations
can be measured.

Environmental Significance

Pesticides are used to control weeds and
insects in a wide variety of agricultural,
urban, and suburban settings. However,
their use may have unintended conse-
quences, such as contaminating drinking
water and threatening a healthy habitat for
wildlife, fish, and other aquatic organisms.
Concentrations of pesticides detected were
below USEPA standards and guidelines for
drinking water. However, four pesticides—
diazinon, malathion, and mevinphos (insecti-
cides), and diuron (an herbicide)—exceeded
maximum concentrations recommended by
the National Academy of Sciences for the
protection of freshwater organisms at seven
streams. Moreover, moderately high concen-
trations of diazinon found in Mercer Creek
at three different times of the year indicate
sustained concentrations that could have
long-term adverse impacts on some aquatic
organisms.