Toxic chemicals ranging from pesticides to metals have been found in all water basins of Oregon, according to a new study.

Research conducted by the Oregon Department of Environmental Quality's (DEQ) Laboratory and Environmental Assessment Program showed that some sites had levels above state criteria or benchmarks for human health and aquatic life.

Water samples were collected from 177 monitoring sites across the state over a period of five years, from 2008 to 2013. DEQ experts analyzed the samples, which came from large rivers, small streams and coastal estuaries, for more than 500 different chemicals.

Tests looked for the presence of a wide range of substances, including: industrial solvents; PCBs; metals such as arsenic, lead, copper and cadmium; flame retardants; pesticides that are used today and others that have been banned, such as DDT and dieldrin; combustion by-products; and consumer product constituents such as acetaminophen and codeine.

DEQ detected 128 of the chemicals it looked for, although most were at very low concentrations. The Department noted that the largest variety of chemicals detected was in the Willamette River and Hood River basins, two areas with population centers as well as agricultural and industrial activities.

This study helps provide the baseline data needed to conduct future water toxics monitoring and also to investigate areas that may need additional work, explained Aaron Borisenko, manager of the Water Quality Monitoring Program.

The full Statewide Water Quality Toxics Assessment report is available here.