DEQ completed its “snapshot” ecological assessment of the Lower Mid-Columbia River, which covers 150 miles between Bonneville Dam on the west and McNary Dam on the east. This study –- the first of its kind on this section of the Columbia -- showed that while the river’s fish and bank habitat is degraded, its water quality is generally good, with low levels of metals and organic compounds known as polyacromatic hydrocarbons. Unfortunately, bass and largescale sucker fish fillets sampled from the river as part of this study show accumulation of potentially harmful levels of mercury, chlorinated pesticides and other toxic or cancer-causing chemicals, including dioxins, furans, and PCBs.
This assessment fills information gaps and compliments studies conducted by states, tribes, federal agencies and non-governmental organizations to gauge conditions, identify problems and find solutions to pollution issues affecting the Columbia River. The U.S. Environmental Protection Agency listed the Columbia Basin as one of seven Great Water Bodies deserving of special attention and protection from environmental harm.