Nutrient elements and heavy metals in the sediment of Baiyangdian and Taihu Lakes: A comparative analysis of pollution trends

Abstract

Based on the sample data on the concentrations of nutrient elements and heavy metals in the sediment collected from Baiyangdian Lake (BL) in June 2004, the pollution level and the distribution of N, P, organic matter (OM), and the heavy metals Cu, Zn, Cd and Pb in water body sediment were analyzed. The pollution trends and current loads between BL and Taihu Lake (TL) were compared using relevant data from BL obtained in 1982 and 1994 and from TL in 1988 and 2000. The findings showed an ever-increasing trend of pollution year by year both in the sediment of BL and TL, although N and P pollution was somehow controlled at the end of the 1990s. The pollution situation in the BL area indicated that the downriver regions were more seriously polluted than the upriver regions, and the most heavily polluted sites were the outlet of the Fuhe River, the original wastewater reservoir of Tanghe River, and the densely populated Chunshui and Wangjiazhai villages. For the TL, the northern lakeside regions were found to be more seriously polluted than the southern regions, although the center of the lake was still relatively pollution free. The most heavily polluted spots were Wuli Lake, Meiliang Bay near Changzhou, Wuxi and other neighboring cities. While the Cd pollution in BL was greater than that in TL, there were not many differences in the average loads of Cu, Zn and Pb. This paper discusses the alternative measures to deal with the different pollution levels in these two lakes.