广西近岸海水和沉积物中有机氯农药的分布及生态风险

Residue Characteristics and Ecological Risk Assessment of Organochlorine Pesticides in Coastal Waters and Sediments of Guangxi

通过对广西近岸水体和沉积物中2类有机氯农药(OCPs,包括HCHs和DDTs)的大面调查,评估了广西近岸海域OCPs的分布特征、污染状况和生态风险。结果显示:广西近岸海域的海水中所有站位都未检出HCHs和DDTs,所有站位的沉积物中也未检出HCHs, 43个沉积物站位中DDTs的检出率为11.6%,沉积物中DDTs含量范围为nd~3.7 ng/g。研究表明:广西近岸水体及沉积物中OCPs的污染水平很低,沉积物中DDTs具有较为明显的空间分布规律,呈现出渔港附近含量高,以及TOC (有机碳)含量较高的河口附近含量高的特征。船舶防污漆可能是造成渔港附近DDTs含量较高的主要原因,部分河口站位主要受河流输入污染物影响,DDTs主要来源于历史残留,沉积物中TOC含量是影响DDTs残留分布的重要因素,DDTs易与悬浮物中的有机质通过吸附络合结合而沉积。生态风险评价结果显示:广西近岸海水的HCHs和DDTs生态风险极低,沉积物的HCHs生态风险也极低,沉积物中DDTs的潜在生态风险总体很低。

The distribution characteristics,pollution status and ecological risks of organochlorine pesticides in the coastal waters and sediments of Guangxi were evaluated through a comprehensive survey of two types of organochlorine pesticides(OCPs,including HCHs and DDTs).The results showed that HCHs and DDTs were not detected at all sites in the sea water of Guangxi coastal waters,and HCHs were not detected in the sediments at all sites.The detection rate of DDTs at 43 sediment sites was 11.6%,and the concentration of DDTs in the sediments varied from nd to 3.7 ng/g.The research showed that the pollution level of OCPs in the coastal water and sediment of Guangxi was very low,and the DDTs in the sediment had a relatively obvious spatial distribution law,showing the characteristics of high DDTs content near fishing ports and estuaries with high TOC(organic carbon)content.Ship antifouling paint might be the main reason for the high content near the fishing port.Some estuarine stations were mainly affected by river input pollutants.DDTs mainly came from historical residues.TOC content in sediments was an important factor affecting the distribution of DDTs residues.DDTs were easy to deposit by combining with organic matter in suspended solids through adsorption and complexation.The ecological risk assessment results showed that the ecological risk of HCHs and DDTs in the coastal seawater of Guangxi was extremely low,and the ecological risk of HCHs in the sediment was also extremely low.The potential ecological risk of DDTs in the sediment was generally low.