| Persistent organic pollutants (POPs) have the characteristics of environmental persistence, semi-volatility, bio-magnification and highly toxicity. For adverse effects on humans and other animals, POPs have now represented a global environmental problem and received great attention around the world. Distribution, migration, transference and ecotoxicological of POPs in marine sediments were the important part of study POPs’s behavior of the global distribution, pollution levels, and ecological risk. The paper investigated 11 organochlorine pesticides (OCPs) and 22 polychlorinated biphenyls (PCBs) in marine of Yangtze River Delta and adjacent sea, the Enantiomeric fractions (EFs) value of chiral POPs were determined, spatial distribution of POPs with chiral signal were obtained, pollution status and ecological risks of POPs in the study marine environment were also assessed. Furthermore, based on the composition characteristics, principal components analyse and EFs value, source of POPs were surveyed. All the investigation would gain pollution status of POPs in the Yangtze River Delta and adjacent sea, apply as the scientific for pollutant control and management, and have great significance for protecting people’s health and safety. The main conclusions in the paper were as follows:(1) Based on enantiomeric level, residues and source of OCPs in surface sediments of Yangtze River Estuary and adjacent sea (30.0oN-32.0oN, 121.0oE-127.0oE) were surveyed. Total OCPs concentrations ranged from 0.46 to 4.99 ng/g dry weight (dw), with the highest concentrations found in the river-sea boundary zone which is so-called“marginal filter”. The predominantβ-HCH and lowα-HCH/γ-HCH ratios indicated that the residues of HCHs in these places mainly originated from the historical usage of technical HCH. However, the ratios of 2,4-DDT/4,4-DDT higher than 0.3 and ratios of (DDE + DDD)/DDT less than 0.5 reflected a cocktail input pattern of fresh and weathered DDTs. Ratio of TC/CC was 2.4, implying fresh input pattern. Furthermore, Enantiomeric analysis showed that the degradation of chiral OCPs were enantioselective, resulting in enrichment of (-) enantiomers forα-HCH and 2,4-DDD in all samples and for 2,4-DDT in part samples.(2) Residues and source of PCBs in surface sediments of Yangtze River Estuary and adjacent sea were analysed. Total concentrations of PCBs ranged from 5.08 to 19.64 ng/g dw, with the highest concentrations also found in the zone which is of“marginal filter”. The PCB levels were sharply decreased from the east of the 124oE, which illustrates that the contaminated PCBs have not been transported to the open sea and confirms a dispersion of PCBs moving seawards. Low-chlorinated PCBs, dominated by tri-PCB, were identified as the prevalent contaminate of surface sediments, and the top three PCB congeners were lighter chlorinated congeners (PCB 8, PCB 18 and PCB 28). The result of the principal component analysis revealed that all samples were similar in composition to Aroclor 1242.(3) The spatial distribution and source of OCPs and PCBs in sediment core (30.5oN, 124oE) of Yangtze River Estuary and adjacent sea were surveyed. Concentrations of OCPs were very low before 1960s, However, the flux of OCPs continued to increase at a steady pace after 1960s. Although production was banned legally in 1983 in China, concentrations of OCPs keep increased due to the Economic development and population growth. Between 1950 to mid-1970s, the concentrations ofΣPCBs increase at a steady pace. A small dip of PCB fluxes in the late-1970s was evident, probably parallel to the period that the PCBs production was banned legally in 1974 in China. After 1980s, the PCB fluxes started to rise again.(4) Based on the enantiomeric level, spatial distribution and source of OCPs in surface sediments of Xiangshan Bay, Sanmen Bay and Yueqing Bay, the coastal of Zhejiang provinces were surveyed. Total OCPs concentrations ranged from0.93 to 23.2 ng/g, 3.33 to 7.41 ng/g and 2.11 to 18.15 ng/g dw, respectively. When compared to the other estuaries or bays worldwide, residues of OCPs in the sampling stations were in the moderate level. According to the compositional patterns, the residues of HCHs were mainly originated from the historical usage. However, the DDT pollution was attributable to a mixed usage of technical DDT and dicofol. Additionally, the degradation of chiral OCPs were enantioselective, resulting in enrichment of (-)-enantiomers forα-HCH, 2,4-DDT and 2,4-DDD in all samples(5) The spatial distribution and source of PCBs in surface sediments of Xiangshan Bay, Sanmen Bay and Yueqing Bay, the coastal of Zhejiang provinces were surveyed. Total concentrations of PCBs ranged from 9.51 to 12.91 ng/g, 9.33 to 19.60 ng/g and 9.80 to 17.77 ng/g dw, respectively. When compared to the other estuaries or bays worldwide, residues of PCBs in the sampling stations were in the moderate level. Low-chlorinated PCBs, dominated by tri-PCB, were identified as the prevalent contaminate of surface sediments. The result of the principal component analysis revealed that all samples were similar in composition to Aroclor 1242.(6) The vertical distribution and source of OCPs in water and suspended particulate matter (SPM) in Xiangshan Bay were investigated. Total OCPs concentrations ranged from 2.88 to 34.72 ng/L for water samples. The present observation showed both DDTs and HCHs were lower than the Chinese official guideline (GH3838–2002) of gradesⅠ, However, according to EPA quality guideline (EPA822-Z-99-001), concentrations of pesticides exceed the EPA guideline values, the potential health risks may exist to eco-systems and organism. Total OCPs concentrations ranged from 2.47 to 29.94 ng/L in SPM samples. When compared to other estuaries or bays in China, residues of OCPs were in the moderate level.(7) According to the sediment ecotoxicological assessment criteria, pernicious effects would be rarely observed for the residues of 4,4-DDD and∑PCBs in marine environment of Yangtze River Delta and adjacent sea. However, for 4,4-DDT and∑DDTs, adverse effects are expected to occur frequently. Pollution of OCPs in the study areas are of great concern due to they resist degradation by physical, chemical, and biological pathways; trend in bioaccumulate through the food web. |
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