title: Polychlorinated biphenyls (PCBs) in sediments/soils of different wetlands along 100-year coastal reclamation chronosequence in the Pearl River Estuary, China.
abstract: PCBs (polychlorinated biphenyls) were determined in sediment/soil profiles to a depth of 30 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 (∑15 PCBs) decreased with depth along sediment/soil profiles in these three wetlands. The ∑15 PCBs concentrations ranged from 17.68 to 169.26 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, 21.6 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 (10(-3) 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 (P < 0.05), whereas no significant correlations were observed between any PCBs congeners and grain size or aggregate content (P > 0.05).
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, PR China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, PR China. Electronic address: junhongbai@163.com.
authors.forename: Junhong
authors.initials: J
authors.lastname: Bai
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, PR China.
authors.forename: Qiongqiong
authors.initials: Q
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, PR China.
authors.forename: Zhaoqin
authors.initials: Z
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, PR China.
authors.forename: Baoshan
authors.initials: B
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, PR China.
authors.forename: Xinhui
authors.initials: X
authors.lastname: Liu
mesh_terms: D002681:China; D004784:Environmental Monitoring / Q000379:methods; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D025341:Principal Component Analysis; D045483:Rivers / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D053833:Wetlands
chemical_list: D012987:Soil; D011078:Polychlorinated Biphenyls
keywords: Dioxin-like PCBs; PCB congeners; Reclamation chronosequence; Total toxic equivalent; Wetland sediments/soils