Abstract
The marine coastal area is facing serious challenges due to several artificial pollution sources. An investigative biomonitoring survey was conducted along the coastal area of Laizhou Bay, China, which combined an evaluation of organic pollution and biomarker responses in the clam Ruditapes philippinarum. Meanwhile, the contents of polychlorinated biphenyls (PCBs), total petroleum hydrocarbons (TPHs) and nonylphenol (NP) in surface sediments at the biomonitoring sites were measured. The results indicated that a complex mixture by these toxic organic pollutants was prevalent throughout the entire area. Concentrations (mean ± standard error) of PCBs, TPHs and NP in sediments of the study area were 1.90 ± 0.10 µg kg-1, 39.55 ± 2.42 mg kg-1, 9.23 ± 0.41 µg kg-1 dry weight, respectively. Biomarker responses of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), Glutathione S-transferase (GST), total glutathione (GSHt) and lipid peroxidation (LPO) levels were assayed in the gills and digestive glands of R. philippinarum collected from eleven sites. Finally, biomarker responses obtained in gills were selected to calculate the integrated biomarker response (IBR) index and to assess the impact of integrated organic contaminants from different stations. The site S2 exhibited an IBR value of 2.65 and was considered as the place with the greatest stress in coastal environment. The western coast (S1-S4) and eastern coast (S9-S11) exhibited higher environmental stress than the sampling sites along the southern coast of Laizhou Bay. PCBs and NP were the main organic pollutants which have caused high level of pollution pressure on R. philippinarum in Laizhou Bay coastal area. The integrated assessment approach of organic contamination which combined chemical analysis and multi-biomarker responses was proved to be practical and useful in coastal environment assessment programs.
Functional identity enhances aboveground productivity of a coastal saline meadow mediated by Tamarix chinensis in Laizhou Bay, China
