Smelter and mill wastewater outfalls, receiving water, biota, slag heaps, tailings ponds, streams, and coal-burning fly ash dumps were sampled as part of this effort to determine the effect of effluent or residual spillage on aquatic systems. Up to 17% lead, 0.1% cadmium and 5 ppm thallium were found in sediments of streams used for irrigation and drinking water below copper and zinc extractive industries in high runoff regions. Groundwater infiltration in the Northwest and Ozarks provides mine drainage water which is used as process water in mills. This water transports potentially toxic wastes into naturally erosive bottom sediments thereby contaminating the food chain. Prevention techniques recommended here include separation of waste streams, protection of tailing dams from flood erosion, and recycle of mill and smelter wastewater. Excess water discharged can be treated with lime at elevated pH to precipitate heavy metals and to prevent leaching of sediment already in streams.

Prepared under contract no. 68-01-0726. Issued August 1977.