Trace-element concentrations in water, streambed sediment, and aquatic invertebrates at select locations in the Klamath River and major tributaries, 2018-2019

The U.S. Geological Survey is monitoring concentrations of metals and other trace elements in water, streambed sediment, and aquatic invertebrates at 6 locations in the middle and lower portions of the mainstem Klamath River from below J.C. Boyle dam in Oregon to near the mouth on the northwestern coast of California. Included are 3 tributary monitoring sites, one each on the Scott, Salmon, and Trinity Rivers. This data release makes available major and minor trace element concentrations in surface water, bed sediment, and aquatic invertebrates collected in September 2018, and in bed sediment collected in September 2019.