A USGS study, done in cooperation with Estuary Partnership and Columbia River Inter-Tribal Fish Commission detected hundreds of contaminants in water samples collected from wastewater-treatment-plant effluent and storm runoff from roads and other urban areas. The water samples were taken in nine cities that line the Columbia River in Oregon and Washington including Wenatchee, Richland, Umatilla, The Dalles, Hood River, Portland, Vancouver, St. Helens, and Longview.
Link here to the full report.