Surface Water Monitoring Program
for Pesticides in Salmonid-Bearing Streams

What’s New
Introduction
Sampling Locations
Results
What’s Ahead
Documents
Links
Contact Information

What’s New

The Departments of Ecology and Agriculture released a report summarizing monitoring data collected in 2010. A summary of the report can be found below under the results section. The report can be viewed by clicking on the following link: Surface Water Monitoring Program for Pesticides in Salmonid-Bearing Streams, 2010 Data Summary.

Study data are available through Ecology's Environmental Information Management (EIM) database. Results for different years can be accessed by entering "Pesticides in Salmonid-Bearing" as the Study Name.

Introduction

Program Goal

Identify, measure, and assess pesticide residues in salmonid-bearing surface waters during the typical use season, over multiple years.

Background

The Washington State Pesticide/Endangered Species Act (ESA) Task Force convened in March 2000 to address the considerable scientific uncertainty surrounding the effects of pesticides on the essential biological requirements of salmonids.

A key question posed by the task force was; "Is there evidence of exposure of pesticide residues to salmonids or the prey base?" They identified "a need for increased surface water monitoring that reflects current land-use patterns/practices as they relate to salmonid habitat and biology."

The task force recommended several Watershed Resource Inventory Areas (WRIAs) for pesticide monitoring. Among these were both agricultural and urban basins. The report detailing these findings is available at the following link: A Process for Evaluating Pesticides in Washington State Surface Waters for Potential Impact to Salmonids.

In 2002, WSDA contracted with Ecology to design and conduct a multi-year surface water monitoring program to characterize pesticide concentrations in salmonid-bearing streams.

Who will be using these data and for what purpose?

The data collected will allow the WSDA, EPA, USFWS, and NOAA to refine exposure assessments for pesticides registered for use in Washington State. Understanding the fate and transport of pesticides used in Washington allows regulators to make appropriate decisions to protect endangered species while minimizing the economic impacts to agriculture.

Parameters

A wide range of current and historical use pesticides (and degradates) are analyzed in this study. Conventional water quality parameters--total suspended solids, pH, conductivity, temperature, dissolved oxygen, and discharge--were measured to better understand chemical fate and toxicity.

Sampling Locations

Site Selection

The primary criteria applied in site selection included: location within an ESA-listed (threatened or endangered) salmonid Evolutionary Significant Unit (ESU), documented salmonid presence, land use, and historical pesticide detections.

Six watersheds were selected for this study because they fit the primary criteria.

Two sub-basins in two watersheds (Cedar-Sammamish and Green-Duwamish) were selected to represent urban basins.
Four sub-basins of the Lower Skagit-Samish watershed were selected to represent western Washington agricultural land use practices.
Eight sub-basins in three watersheds (Lower Yakima, Wenatchee, Entiat) were selected to represent eastern Washington agricultural land use practices.

Urban Sites

Thornton Creek is located in the Cedar-Sammamish Watershed Resource Inventory Area (WRIA) 8 and Longfellow Creek is located in the Green-Duwamish WRIA 9 in the Puget Sound basin. WRIA 8 and 9 are within the Puget Sound Chinook ESU (threatened), Coastal Puget Sound Bull Trout Distinct Population Segment (DPS) (threatened), Puget Sound Steelhead (threatened) and the Puget Sound/Strait of Georgia Coho ESU (species of concern).

Western Washington Agricultural Sites

Western Washington agriculture is represented by four drainages within the Lower Skagit-Samish WRIA 3: Big Ditch, Browns Slough, Indian Slough, and Samish River. The Lower Skagit-Samish WRIA supports several Puget Sound salmonid populations (Chinook, Coho, Chum, Pink, Sockeye, Bull Trout/Dolly Varden, and Steelhead).

The Lower Skagit-Samish watershed has numerous minor crops such as bulbs (daffodil, iris, and tulip), berries, seed crops, sod, potatoes, peas, and cucumber. The diversity of crops, pesticide use, and large percentages of cropped area are the driving forces for choosing WRIA 3 to represent western Washington agriculture.

Eastern Washington Agricultural Sites

Eastern Washington agriculture is represented by eight drainages within three watersheds. The Lower Yakima WRIA 37: Marion Drain, Sulphur Creek Wasteway, and Spring Creek; Wenatchee WRIA 45: Wenatchee River, Brender Creek, Mission Creek, Peshastin Creek; and Entiat WRIA 46: Entiat River. Each WRIA supports diverse salmonid populations (Chinook, Coho, Sockeye, Steelhead, and Bull Trout/Dolly Varden) All three watersheds have numerous minor crops such as currants, cherries, alfalfa, mint, asparagus, apples, and pears. The diversity of crops, pesticide use, and large percentages of cropped area are the driving forces for choosing these WRIAs to represent eastern Washington agriculture.

Results

Results of this ongoing study are presented as annual data summaries, supplemented by three-year reviews. When possible, the three-year review will assess potential pesticide effects to salmonids, their prey base, and habitat. Dissimilar sample regimes of 2003 to years 2004-2005 reduced the ability for direct comparison of the first three-year data set. More detailed effects analyses will take place according to weight of evidence, over multiple years.

Temporal trends and potential impacts to aquatic species are investigated through comparison to (1) EPA registration toxicological criteria for fish, aquatic invertebrates, and plants, (2) Washington State Water Quality Standards, and (3) EPA National Recommended Water Quality Criteria.

2010 Data Summary

This report presents 2010 pesticide results for two urban basins (Thornton Creek in the Cedar-Sammamish basin and Longfellow Creek in the Green-Duwamish basin) and four agricultural basins (lower Skagit-Samish, lower Yakima, Wenatchee, and Entiat). In 2010, surface water samples were analyzed for over 170 pesticides and pesticide degradates.

Changes during 2010 include purchase of a new laboratory instrument for carbamate pesticide analysis that allowed for better sensitivity and a significant reduction in identification uncertainty, thus decreasing the potential for false positive and negatives.

During 2010 very few pesticide detections were above (did not meet) water quality criteria or standards. An intensive triennial review of pesticide results will be conducted after the 2011 monitoring season.

What’s Ahead

A report summarizing results from sampling conducted in 2011 will be released in early 2012.

Documents

For detailed information and results, follow the link to each report.

To download results data, follow the link below to Ecology's EIM system. Study data are available through Ecology's Environmental Information Management (EIM) database. Results for different years can be accessed by entering "Pesticides in Salmonid-Bearing" as the Study Name.