Occurrence, transport, and fate of trace elements, Blue River Basin, Summit County, Colorado: an integrated approach

Mining activities in the Blue River Basin, Summit County, Colorado, have affected the trace-element chemistry and biota along French Gulch and the Blue River. Elevated concentrations of As, Cd, Cu, Pb, and Zn were present in the bed and suspended sediments. Bed sediment trace-element concentrations were high in the streams in and near mining activities in the basin and remained high as water flowed into Dillon Reservoir about 3.5 km downstream. Bed-sediment (< 63 μm) data were useful in assessing the distribution of trace elements in the basin. Suspended-sediment measurements provided information as to the transport of the trace elements. Filtered (< 0.45 μm) water-column trace-element concentrations were orders of magnitude less than the sediment concentrations. Concentrations of Cd and Zn in the water column at some sites exceeded stream water-quality standards. Elevated trace-element concentrations in the sediment and water column are a source of contamination and must be considered in water-quality management of the Blue River Basin.