广西合浦廉州湾贝类养殖区表层沉积物重金属汞和砷污染评价

Assessment on pollution of heavy metal Hg and As in surface sediment of shellfish culture areas in Hepu Lianzhou Bay

【目的】掌握广西合浦廉州湾贝类养殖区表层沉积物重金属的污染状况及发展趋势,为广西海水贝类养殖区重金属污染的治理提供科学依据。【方法】根据广西合浦廉州湾养殖区域地形结构特点及养殖生产情况,分别设党江浅水区（1#）、党江深水区（2#）、沙岗（3#）、西场（4#）4个监测点,于2008~2010年夏季、秋季对4个监测点进行6次采样,采用GB 18668-2002《海洋沉积物质量》标准和地积累指数（Igeo）评价其重金属汞（Hg）和砷（As）的污染程度。【结果】党江浅水区（1#）、党江深水区（2#）和沙岗（3#）3个监测点Hg的Igeo较小,无Hg污染;而西场监测点（4#）Hg的Igeo为1.91,地积累级别为2,Hg污染程度为中级。4个监测点均受到不同程度的As污染：沙岗（3#）、党江浅水区（1#）、西场（4#）和党江深水区（2#）的污染程度分别属无~中级、中级、中级和中~强级,地积累级别分别为1、2、2和3。【结论】广西合浦廉州湾贝类养殖区的水环境已开始受到重金属污染,应引起重视并加强监控力度。

【Objective】Pollution status and future tendency of heavy metal Hg and As in surface sediment of shellfish culture areas in Hepu Lianzhou Bay were analyzed to provide scientific references for controlling heavy metal pollution in seawater shellfish culture areas in Guangxi. 【Method】According to geographical features and aquaculture situation, four monitor points（Dangjiang shoal waters, Dangjiang deep waters, Shagang, Xichang） in shellfish culture areas in Hepu of Guangxi were set up as 1#,2#, 3# and 4#. Samples from the four monitor points were collected for six times in summer and fall during 2008 to 2010. National marine sediment quality standard and index of geo-accumulation were used to assess the heavy metal pollution of this district. The pollution status of heavy metal Hg and As was evaluated using GB 18668-2002 Ocean Sediments Quality and geoaccumulation（Igeo）. 【Result】The results showed that the heavy metal Hg in Xichang monitor point（4#） had intermediate pollution with geo-accumulation level of 2 and the Igeoof 1.91, while the other three points had no heavy metal Hg pollution. But the four monitor points were polluted by heavy metal As with different extents. The pollution level of monitor point 3#, 1#, 4#, 2# was zero-intermediate, intermediate, intermediate and intermediate-high with the geo-accumulation level of 1, 2, 2, 3. 【Conclusion】The ocean environment in shellfish culture areas of Hepu Lianzhou Bay is deteriorating, hence more efforts should be made for monitoring strength.