Influence of mining-related activities on concentrations of metals in water and sediment from streams of the Black Hills, South Dakota

Water and sediment samples were collected from streams in Spearfish Creek, Whitewood Creek, and Bear Butte Creek watersheds in the Black Hills, SD, an area impacted by gold mining operations. Arsenic concentrations that excee ded the U.S. Environmental Protection Agency's Maximum Concentration Limit of 50 mug/L for drinking water were found in water from Annie Creek, a trib utary of Spearfish creek, and from Whitewood Creek. Gold Run, a tributary o f Whitewood Creek, and Annie Creek contained Se concentrations in water tha t exceeded the EPA Ecotox threshold of 5 mug/L and were classified as a hig h hazard for Se accumulation from water into the planktonic food chain and for resultant toxicity to fish and aquatic birds. Concentrations of As, Cd, Cu, Hg, Ni, Pb, and Zn in sediment exceeded EPA Ecotox thresholds in one o r more of the watersheds suggesting potential adverse ecological effects. S ediment from Rubicon Creek, a tributary of Spearfish Creek, contained Se co ncentrations high enough (4.0 mug/g) to be a moderate hazard for accumulati on from sediments into the benthic food chain, with resultant dietary toxic ity to fish and aquatic birds. These results are discussed in light of hist orical mining activities and recent clean-up and reclamation efforts. Based on the results and comparisons to Ecotox tresholds, further studies of eco logical effects are warranted.