Surface-water and groundwater contamination by industrial wastes or chemical spills is a concern particularly near sources of large water supply near urban areas, along the major rivers, and in principal aquifers. Organic compounds and toxic trace elements from petroleum products, from storage tanks or pipelines, or from industrial sites are a hazard to aquatic biological communities and to water supply. Sedimentation and contamination of surface water can occur after urban runoff and combined stormwater-sewer overflow when the capacity of waste water treatment facilities are exceeded. Nutrients, bacteria, and turbidity affect water supplies in many areas. Contamination of surface waters and ground waters by nutrients and pesticides used in agricultural and urban areas can occur where land uses are highly mixed.
Acidic precipitation affects water quality and biological communities.
Naturally occurring radiochemicals, especially radon, affect the quality of groundwater supplies. The discharge of heated water used for cooling thermoelectric power plants adversely affects stream water quality and biologic communities and can cause reductions in dissolved oxygen concentrations, algal blooms, and growth of pathogens. The liaison committee for the Allegheny-Monongahela River Basin study was formed and convened in June 1994.