BaselineBaseline survey of sediments and marine organisms in Liaohe Estuary: Heavy metals, polychlorinated biphenyls and organochlorine pesticides

- The concentrations of heavy metals, PCBs and OCPs in the sediments and marine organisms were investigated in Liaohe Estuary.
- Heavy metal contents in the sediments were observed in the following order: Cr > Cu > Pb > As > Cd > Hg.
- Heavy metal pollution in Liaohe Estuary is mainly dominated by Cd and Hg.
- The increased concentration of DDTs indicated that there may be a fresh DDTs input.

A geographically extensive investigation was carried out to analyze the concentrations of heavy metals, PCBs and OCPs in the sediments and marine organisms collected from the Liaohe Estuary. In order to determine the spatial distribution and potential ecological risk of heavy metals, the surface sediments were collected from 44 sites in the Liaohe Estuary. The results showed that the heavy metal contents in the sediments were observed in the following order: Cr (11.2-84.8 mg/kg) > Cu (1.7-47.9 mg/kg) > Pb (4.3-28.3 mg/kg) > As (1.61-12.77 mg/kg) > Cd (0.06-0.47 mg/kg) > Hg (0.005-0.113 mg/kg). In comparison with the concentrations of heavy metals and POPs in other regions, the concentrations of As, Pb and DDTs in the Liaohe Estuary were generally low, and other pollutant concentrations were inconsistent with those reported in other regions. The contamination factor (CF), the pollution load index (PLI), the geoaccumulation index and the potential ecological risk index were used to analyze the pollution situation, which showed that the heavy metal pollution in Liaohe Estuary is mainly dominated by Cd and Hg. The concentrations of the four heavy metals varied significantly in the three kinds of tested organisms (fish, mollusk and crustacean), indicating the different accumulative abilities of the species. The results obtained in this study provide useful information background information for further ecology investigation and management in this region.