Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6315063 | Environmental Pollution | 2016 | 10 Pages |
Abstract
PCBs (polychlorinated biphenyls) were determined in sediment/soil profiles to a depth of 30Â cm from three different wetlands (i.e., ditch wetlands, riparian wetlands and reclaimed wetlands) of the Pearl River Estuary to elucidate their levels, distribution and toxic risks along a 100-year chronosequence of reclamation. All detected PCB congeners and the total 15 PCBs (â15 PCBs) decreased with depth along sediment/soil profiles in these three wetlands. The â15 PCBs concentrations ranged from 17.68 to 169.26Â ng/g in surface sediments/soils. Generally, old wetlands tended to have higher PCB concentrations than younger ones. The dominant PCB congeners at all sampling sites were light PCB homologues (i.e., tetra-CBs and tri-CBs). According to the sediment quality guideline, the average PCB concentrations exceeded the threshold effects level (TEL, 21.6Â ng/g) at most of the sampling sites, exhibiting possible adverse biological effects, which were dominantly caused by light PCB congeners. The total toxic equivalent (TEQ) concentrations of 10 dioxin-like PCBs (DL-PCBs) detected at all sampling sites ranged from 0.04 to 852.7 (10â3Â ng/g), mainly affected by PCB126. Only DL-PCB concentrations in ditch and riparian wetland sediments with 40-year reclamation histories (i.e., D40 and Ri40) exhibited moderate adverse biological effects according to SQGQ values. Principal component analysis indicated that PCBs in three wetland sediments/soils mainly originated from Aroclor 1016, 1242, and 1248. Correlation analysis showed that sediment/soil organic carbon content had a significant correlation with the concentrations of several PCB congeners (PÂ <Â 0.05), whereas no significant correlations were observed between any PCBs congeners and grain size or aggregate content (PÂ >Â 0.05).
Keywords
Related Topics
Life Sciences
Environmental Science
Environmental Chemistry
Authors
Qingqing Zhao, Junhong Bai, Qiongqiong Lu, Zhaoqin Gao, Jia Jia, Baoshan Cui, Xinhui Liu,