Water Quality Improvement Projects (TMDLs) > Yakima Watershed Area Projects > Yakima Watershed Area Toxics Project

Water Quality Improvement Project
Yakima Watershed Area:
Toxics

Water quality issues

Water quality testing found toxic chemicals in the water of the Yakima River and some of its tributaries. Most of these chemicals are banned pesticides or PCBs (polychlorinated biphenyls) that are no longer used.

Past studies show that some of these chemicals get into the water when contaminated soil erodes and enters the water.  Some of these chemicals were also found in fish living in the Yakima River and some of its tributaries. (See Study Area map)

Why this matters

Toxic chemicals, which are persistent chemicals in the environment, are a growing concern for the state. They can contaminate the food (fish, shellfish, etc.) that people may eat.  In the Yakima River valley, these chemicals are mostly from agricultural pesticides and industrial pollution. They can be found in our air, water, soil, and wildlife. And, they are showing up in people's bodies, which may lead to health problems.

Status of the project

Farmers and other land users in the watershed implemented existing TMDLs that may help some of the water quality problems. The Roza Sunnyside Board of Joint Control and Kittitas County Water Purveyors adopted water quality policies that reduce the amount of polluted runoff entering into tributaries of the Yakima River. Many agricultural operations adopted practices that prevent or reduce their impact to streams.

Monitoring of DDT, dieldrin, and other chlorinated pesticides continues to measure the progress of other water quality improvement project work to bring the watershed into compliance with state water quality standards.

Ecology conducted a study on water quality conditions in the Yakima River watershed in 2006. Although additional sources of toxic contamination to the surface waters were found, changes in agricultural practices have reduced the amount of pollution coming from irrigation runoff. While some Yakima River fish still have pesticides in their flesh, the levels are much improved (reduced) compared to previous years. This reduction in pesticide levels in fish tissue allowed the Washington Department of Health to drop their advisory on DDT in lower Yakima River fish.

The technical study for the Yakima Toxics Project was published in 2010.

Technical information

Quality Assurance Project Plan - Chlorinated Pesticides, PCBs, and Dioxins in Yakima River Fish - 2006: Assessing Progress Toward TMDL Targets and Updating the Fish Consumption Advisory (Ecology Publication)
www.ecy.wa.gov/biblio/0603111.html

Chlorinated Pesticides, PCBs, and Dioxins in Yakima River Fish in 2006:  Data Summary and Comparison to Human Health Criteria (Ecology Publication)
www.ecy.wa.gov/biblio/0703036.html

Quality Assurance Project Plan- Yakima River Chlorinated Pesticides, PCBs, Suspended Sediment, and Turbidity Total Maximum Daily Load Study (Ecology Publication)
www.ecy.wa.gov/biblio/0703107.html

Yakima River Pesticides and PCBs Total Maximum Daily Load: Volume 1: Water Quality Study Findings (Ecology Publication)
www.ecy.wa.gov/biblio/1003018.html

Related information

New information available on toxic chemicals in Yakima River (Ecology news release)
www.ecy.wa.gov/news/2010news/2010-088.html

Yakima River Watershed Toxics Study (Ecology Publication)
www.ecy.wa.gov/biblio/0610069.html

Frequently Asked Questions: Yakima River Watershed Toxics Study: Progress Update (Ecology Publication)
www.ecy.wa.gov/biblio/0910088.html

Fish Consumption Advisories for Yakima River (WA Department of Health)
www.doh.wa.gov/ehp/oehas/fish/fishadvisories.htm#yakimariver

WRIA 37: Lower Yakima Watershed Information (Environmental Assessment Program web site)
www.ecy.wa.gov/apps/watersheds/wriapages/37.html

WRIA 38: Naches Watershed Information (Environmental Assessment Program web site)
www.ecy.wa.gov/apps/watersheds/wriapages/38.html

WRIA 39: Upper Yakima Watershed Information (Environmental Assessment Program web site)
www.ecy.wa.gov/apps/watersheds/wriapages/39.html

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