Water pollution studies on Lake Illawarra. III. Distribution of heavy metals in sediments

Abstract

Samples of recent sediments from 18 sites in Lake Illawarra showed marked enrichment of copper, zinc, cadmium and lead. The highest concentrations were found in Griffins Bay in the north-east corner of the lake, which is closest to the Port Kembla industrial complex. Maximum enrichments for copper, zinc and lead are respectively 4, 34 and 11 times the background concentrations found in deep cores. By comparison of vertical profiles of heavy metal concentration with historical data on the growth of metal smelting industries in the Illawarra region, the recent sedimentation rate has been estimated as 2.5-3 mm/year. A depth of 40-50 cm below the surface of the sediment marks the beginning of human influence on the lake.