Trace Metals in the Columbia River Estuary Following the 18 May 1980 Eruption of Mount St. Helens

Abstract

Dissolved and suspended concentrations of cadmium, copper, iron, manganese, nickel, lead, and zinc were measured in the Columbia River Estuary following the 18 May 1980 eruption of Mount St. Helens. Soluble concentrations of these trace elements were not substantially elevated by the influx of volcanic ash and mud into the estuary during this period, except for somewhat higher than usual concentrations of manganese and copper. A laboratory experiment indicates that manganese leached from volcanic debris in fresh water and in the transition from fresh to slightly saline water probably caused the elevated Mn concentrations. Copper in solution may also have been enhanced slightly by leaching from the material into fresh water.