Total and Bioavailable Particulate Phosphorus Loads from the Niagara River in 1987 and 1988

Abstract

The forms and concentrations of phosphorus were determined in suspended sediments of the Niagara River for the purpose of assessing the annual loads of bioavailable particulate and total particulate P. The bioavailable phosphorus (BAP) in suspended sediments accounted for about 44% of the total particulate P (TPP). Concentrations of BAP and TPP were significantly higher in the summer than in the winter, due to the presence of material of biogenic origin entering the river from Lake Erie. Apatite-P, generally considered to be biologically inert in aquatic environments, accounted for about 26% of the TPP. The calculated annual loadings of particulate BAP and TPP in 1987 were 0.92 × 10 6 and 2.04 × 10 6 kg/year, respectively. In 1988 the calculated BAP and TPP loadings from suspended sediments were 0.91 × 10 6 and 2.03 × 10 6 kg/year, respectively. The results indicate that only about 45% of the TPP load is bioavailable and is of environmental significance. This has important implications for implementation of phosphorus control programs and for the lakewide management plans considered now for Lake Ontario.