History of Phosphorus Loading to Onondaga Lake

Abstract

The history of phosphorus loading to, and efflux from, Onondaga Lake, New York, is presented for a 12‐yr period (1970–1981), during which several phosphorus management measures were taken. A ten‐fold reduction in phosphorus loading since 1970 has been achieved through implementation of reclamation measures, which included a ban on high phosphorus detergents and the addition of secondary and tertiary processes at the adjoining sewage treatment plant. Significant reductions in lake phytoplankton concentrations have not accompanied the reduction in phosphorus loading, indicating the lake remains nutrient‐saturated. An unusually high fraction of phosphorus received by the lake is retained, apparently as a result of enhanced phosphorus deposition associated with the industrial loading of calcium from an adjoining chloralkali manufacturer. One‐tenth of the reported substantial reduction in phosphorus loading to Lake Ontario from 1970–1979 is attributable to the reduction in loading to Onondaga Lake. The nature of the phosphorus associations in the lake's sediments indicates that sediment interactions should not act to compensate for further reductions in external phosphorus loading.