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Department of Ecology News Release - July 5, 2000
00-118
YAKIMA - Results of two separate water quality studies will influence future clean-up priorities on the upper Yakima River.
The Washington Department of Ecology (Ecology) initiated the studies in 1999 to verify whether concentrations of metals and pesticides in the upper river are at levels that require inclusion on a list that identifies impaired water bodies in the state.
Copper, cadmium, mercury and silver, as well as the pesticides DDT and dieldrin, are identified as contaminants in the upper Yakima River on the 1998 303(d) list prepared by the state in compliance with the federal Clean Water Act.
A yearlong study was unable to identify any levels of copper, cadmium, mercury and silver above state water-quality standards for the listed metals. As a result, a recommendation will be made to remove the upper river from the list for those metals.
A second study examining two persistent and bioaccumulative pesticides did verify that DDT and dieldrin continue to be found in upper-river fish. The study confirmed findings of previous studies in 1985 by Ecology and in 1989 by the U.S. Geologic Survey (USGS).
"DDT and dieldrin are particularly troublesome because they stay in the environment and tend to collect and remain in the fatty tissue of animals," explained Chris Coffin, a water quality specialist for Ecology. "Although they have been banned for many years, they continue to have an effect on the food chain as higher animals consume lower contaminated animals."
In 1993, state and local health officials issued a recommendation that people limit their consumption of bottom fish from the lower Yakima River. Sediment erosion from farmlands has been linked to residual pesticides found in the Yakima River and its tributaries.
To address the pollution concerns, a water clean-up plan (known as a "total maximum daily load," or TMDL process) will soon be developed for the upper Yakima Basin similar to the cleanup plan for pesticides and sediment currently under way in the lower basin.
Contact: Chris Coffin, Water Quality Specialist, (509) 454-7860
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
