Potential impacts on aquatic ecosystems from the release of trace elements in geothermal fluids. Environmental Sciences Division publication No. 1097

Analyses of 14 trace elements found in hydrothermal fluids from various geothermal reservoirs in the western United States are presented. The concentrations of these elements, which include As, B, Ba, Br, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Rb, Ti and Zn, vary over orders of magnitude between reservoirs. Potential impacts are conservatively assessed on the basis of toxicity to freshwater biota, and bioaccumulation in food fish to the point where consumption might be hazardous to human health. Trace element concentrations generally range from benign levels to levels which might prove toxic to freshwater biota and contaminate food fisheries. The need for site-specific analyses and careful handling of geothermal fluids in order to minimize potential impacts is stressed