江苏某拆船厂船舶压载水舱沉积物重金属形态特征及生态风险评价

采用Tessier连续提取法分析了10艘船舶的压载水舱沉积物中6种重金属的赋存形态，并进行生态风险评价。结果表明，沉积物中Zn含量最高，平均浓度为3915.73×10-6。Cd含量最低，为6.17×10-6。Ni、Pb和Cr主要以残渣态存在，Cd以有机态和残渣态为主，Cu主要为有机态，Zn多为铁/锰态。Hakanson生态风险指数评价各重金属污染程度依次为Cd > Zn > Cu > Pb > Ni > Cr。次生相与原生相比值法分析显示，沉积物中Cr、Ni、Pb污染较轻，Cd和Zn处于重度污染水平，表明船舶压载水舱沉积物重金属的潜在生物毒性较大，应对其加强管理并合理处置。

The speciation and ecological risk of heavy metals in the ballast tank sediments from a shipyard of Jiangsu province,China

Tessier sequential extraction procedure was used to analyze the distributions of six kinds of heavy metals in the ballast tank sediments from 10 ships.The ecological risks of the heavy metals were evaluated according to the potential ecological risk index and the ratio of secondary and primary phases.Results show that the average concentration of Zn and Cd are 3915.73×10-6 and 6.17×10-6, which present as the highest and the lowest contents in all of ballast sediments, respectively.In this study, Ni, Pb and Cr are found mainly distributed in the residual form, while Cd mainly exists in the organic and residual fraction.Cu is primarily belonged to the organic form and Zn mainly bounds to the Fe/Mn oxides.Hakanson ecological risk index indicates that the ecological risk of heavy metals is in the order of Cd > Zn > Cu > Pb > Ni > Cr.The risk evaluation of heavy metal based on speciation shows that the pollution of Cr, Ni and Pb in the sediments was light, while the Cd and Zn were at the level of heavy pollution.In conclusion, the heavy metals in ballast tank sediments have high potential bio-toxicity and reasonable managements and treatments are required to prevent the marine environment pollution.