| Organochlorine pesticides (OCPs), which has been well known as typical persistent organic pollutants (POPs), have adverse effects on natural ecosystems and health of human life. Although their production and application have been banned since 1983 in China, high levels of OCPs are still detectable in many environmental media due to their characteristics, such as the highly toxic, lipotropy, semi-volatile and biological accumulation. Thus, the OCPs have gained worldwide concern.Chaohu Lake is located in the middle of Anhui province, is one of the five largest fresh water lake in China. Meanwhile, it is an important living water source for the surrounding residents, and also provides resources for local fisheries development and agricultural irrigation. Owning to estuary is a semi-closed coastal water, freely connect with lake, additionally the river and the lake mixing in here. Therefore, estuary is a area which have the most significant interaction and the strongest effected by human activities.In order to access contamination by organochlorine pesticides (OCPs) from the main estuaries of Chaohu Lake. In this study, I collected both water, surface sediment and Bellamya aeruginosa in 8 estuaries. I used C18 solid phase extraction for water samples and accelerated solvent extraction for surface sediment and Bellamya aeruginosa, respectively, for further liquid concentration, purification, trace enrichment. Accordingly, I analyzed 21 OCPs using chromatography and mass spetrometry. The residue levels and the characteristics were studied. The possible source of the contamination were discussed here, and the potential ecological risk assessment were evaluated. In order to provide basic data for OCPs pollution control. The results showed that:(1) There were 16,18 and 16 kinds of OCPs in water, surface sediment and Bellamya aeruginosa. The total concentration of OCPs ranged from 40.13 to 87.66 ng·L-1 in water samples and from 10.97 to 26.29 ng·g-1 dry weight in surface sediment samples and 11.36 to 15.64 ng·g-1 in Bellamya aeruginosa samples, respectively. The main components were HCHs and DDTs. The residues of HCHs and DDTs in surface sediment and Bellamya aeruginosa are far higher than the corresponding content in the water, indicating that, surface sediment and Bellamya aeruginosa all have a certain enrichment capability.(2) As the whole the tide of the OCPs gross in wate、surface sediment and Bellamya aeruginosa was approximately same. The analysis of variance (ANOVA) were carried out on the content of OCPs in water and surface sediment, the results indicated that, generally, the OCPs content in urban pollution river was higher than soil and water conservation and non-point source pollution river. The urban pollution river becomes the main OCPs pollution source of Chaohu Lake.(3) According to the distributions of HCHs and DDTs components analysis implied that, no matter water, surface sediment or Bellamya aeruginosa the HCHs and DDTs in study areas might derive from the aged and weathered agricultural soils, especially under aerobic conditions.(4) Based on the correlation analysis between the concentrations of OCPs, DDTs, HCHs and TOC in surface sediments. The results showed that there is no correlation between them in surface sediment in the study areas.(5) Compared with other studies, OCPs in Chaohu Lake are in a medium level. HCHs and DDTs in surface water won’t cause harm to the regional environment and human body, basiclly. And the Bellamya aeruginosa also did not exceed the maximum residue limits of standard which we choose, it is not enough to harm human body health.However, OCPs in surface sediment has potential ecological risk, it may cause harm to the ecological environment. In addition, I still need to strengthen the management and control for organochlorine pesticide pollution, due to the biological accumulation and biological amplification. |
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