LAKE-ONTARIO SEDIMENTS IN MONITORING POLLUTION

An investigation was carried out to select locations for long-term mon itoring of inputs of contaminants into Lake Ontario using fine-grained bottom sediments as an historical record of pollution. The sediment s ampling program was designed to determine sediment heterogeneity in th e western, central and eastern depositional basins of the lake. Surfic ial sediments and sediment cores were collected in each basin to obtai n information on horizontal distribution and concentration profiles of major and trace elements in the sediments (Si, Al, Ca, Mg, Fe, Na, K, Ti, Mn, P, As, Co, Cu, Cr, Ni, Pb and Zn). The results of the investi gation indicated that fine-grained sediments in three Lake Ontario dep ositional basins are homogeneous to a high degree, and that only a few sediment cores need to be collected within each basin for the long-te rm monitoring of inputs of contaminants to the lake.