Distribution, composition profiles, source identification and potential risk assessment of Polychlorinated Biphenyls (PCBs) and Dechlorane Plus (DP) in sediments from Liaohe Estuary

Polychlorinated biphenyls (PCBs) and Dechlorane Plus (DP) were analyzed to evaluate the environmental quality in sediments from Liaohe Estuary (LHE), northern China. The concentration of ∑24PCBs ranged from 106.7 to 270.0 pg g−1 dry weight, with a mean value of 186.6 pg g−1 in surface sediments. The PCBs concentrations in the eastern region of Gaizhou Beach (GZB) were higher than those in the western region, indicating that the effects of hydrodynamic transportation and deposition of fine-grained sediments are the factors controlling the distribution and behaviors of PCBs in LHE. Principal component analysis (PCA)-multiple linear regression (MLR) revealed that 15.9% of PCBs in LHE originated from local sources directly discharged by anthropogenic activities, 73.9% from surface runoff of eroded soils contaminated by PCBs and 10.2% from atmospheric deposition and microbial degradation. The concentration of DP varied from 10.1 to 45.7 pg g−1 dry weight, with an average value of 28.0 pg g−1 dry weight. The spatial distribution pattern of DP indicated that hydrodynamic forces and the sedimentary environment were prominent factors influencing the accumulation and distribution of DP in LHE. The mass inventories for a sediment thickness of 2 cm in the whole area of LHE were 4.1 kg and 0.6 kg for ∑24PCBs and DP, respectively. At present, the ecological risk for sediments of LHE is low for both PCBs and DP.