Speciation of heavy metals in sediments from Baihua Lake and Aha Lake

摘要

Baihua Lake and Aha Lake are both drinking-water sources for Guiyang City, the capital of Guizhou Province in southwestern China. In the present research, chemical speciation of chromium (Cr), copper (Cu) and zinc (Zn) in the sediments from these two lakes was studied based on the sequential extraction procedure developed by Tessier et al., and organic matter (OM) was determined by ignition method. The results obtained are as follows: The organic matter amounts in sediments from Baihua Lake and Aha Lake ranged from 11.62 to 18.02% and 8.48 to 13.90%, respectively; Cr and Zn were mainly distributed in residual phase, while Cu mainly existed in oxidizable and residual phases; Levels of Cu distributed in oxidizable phase in sediments from Baihua Lake were higher than those from Aha Lake; Mobility, bioavailability, and toxicity of Cu were low in comparison with Zn and Cr, because Cu was mainly distributed in oxidizable and residual phases in which heavy metals mobility was lower than in the other phases. The Pearson's correlation coefficient between organic matter and Cr in oxidizable phase of the 20 sediment samples collected from the two lakes was up to 0.604 (p < 0.01).