Distribution and risk assessment of organochlorine pesticides and polychlorinated biphenyls in surficial sediments from Lake Baiyangdian

Abstract

To better understand the contamination of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in sediments from Lake Baiyangdian, 20 OCPs and all 209 PCB congeners were measured in 11 surficial sediment samples collected from different locations of Lake Baiyangdian. Moreover, the risks posed by OCPs and PCBs were assessed based on sediment quality guidelines. The results show that 10 OCPs and 24 PCB congeners were detectable. The total OCPs concentrations ranged from 1.22 to 52.45 ng/g(DW) (dry weight), while the total PCBs levels were from below detection limit to 37.61 ng/g. These results indicate a moderate pollution level within China. HCHs and Dieldrin were predominant in all OCPs, which accounted for 39.9% and 31.5% of total OCPs, respectively. Seven sampling sites of Lake Baiyangdian were contaminated by Lindane (γ-HCH) and the other 4 sampling sites were mainly contaminated by industrial HCHs. Moreover, new HCHs inputs might exist in some locations. DDTs levels were relatively low, which suggests that DDTs in Lake Baiyangdian might be the historical residues. PCBs detected in these sediment samples were dominated by low chlorinated PCBs congeners. Mono-, di-and tri-chlorinated biphenyls accounted for 64.73% of the total PCBs. However, it is noted that some new organochlorine pesticide pollution of HCHs may be present in some areas. Ecological risk assessment based on sediment quality guidelines revealed that the risks posed by p,p'-DDD and ∑PCBs were relatively lower, while the risk associated with Dieldrin was of concern. Notably, γ-HCH posed apparent adverse effects on the local ecological system.