Purpose and Scope

This report, prepared by the U.S. Geological Survey at the request of the Confederated Tribes of Warm Springs, summarizes the pesticide and trace element data collected by the ODEQ from 1999 through 2009 in the Hood River basin, Oregon, and uses the data to assess the potential effects of these contaminants on the health of salmonids that spawn and spend the first years of their life in the basin. Concentrations of pesticides and trace elements are compared to water-quality standards and mortality endpoints for fish and aquatic invertebrates, where such standards and endpoints exist. Concentrations of pesticides and trace elements also are compared to sublethal effects on salmonids documented in peer-reviewed literature and U.S. Environmental Protection Agency databases. Finally, the report identifies gaps in information about the occurrence of contaminants toxic to salmonids and aquatic invertebrates in streams of the Hood River basin.

First posted June 17, 2011