厦门贝类养殖区海水、沉积物和养殖贝类体内重金属含量的初步研究

A preliminary study of heavy metal contents in sea water,sediments and cultured shellfish in shellfish culture areas of Xiamen

根据2005年4月和10月厦门贝类养殖区的环境调查资料,着重对贝类养殖区海水、表层沉积物和贝类体内重金属的含量分布进行分析,并对贝类养殖区的生态环境进行质量评价及潜在生态危害评价。结果表明,厦门贝类养殖区海水中Cu、Pb、Cd、Zn的平均含量分别为1.06、1.23、0.05和6.28μg.L-1;沉积物中Cu、Pb、Cd、Zn的平均含量分别为20.0×10-6、39.5×10-6、0.07×10-6和97.3×10-6。贝类体内Cu、Pb、Cd、Zn的平均含量分别为16.3×10-6、0.24×10-6、0.38×10-6和63.9×10-6。生态环境质量评价结果表明,贝类养殖区海水重金属的含量符合第二类《海水水质标准》要求,处于清洁水平;养殖区沉积物重金属的含量符合第一类《海洋沉积物质量》标准,属于较清洁水平。潜在生态危害评价结果,Cu、Pb和Cd的潜在生态危害系数大于Zn,表明Cu、Pb、Cd的潜在危害大于Zn,但整个养殖区沉积物中重金属的潜在危害属于轻微,养殖环境良好。菲律宾蛤仔Ruditapes philippinarum、缢蛏Sinonovacula constricta体内Cu、Pb、Cd、Zn的含量均未超《无公害食品》、《食品中锌限量卫生标准》和《海洋生物质量》标准,但僧帽牡蛎Saccostrea cucullata体内Cu的含量和泥蚶Tegillarca granosa体内Cd的含量已超标。

Based on the data of shellfish culture areas of Xiamen, Fujian province in April and October of 2005, the contents and distributions of heavy metals in the sea water, surface sediments and shellfish organisms were analyzed. Eco-environmental quality and potential ecological risk in the shellfish culture areas were also assessed. The results were summarized as follows. The average contents of Cu, Pb, Cd and Zn were 1.06, 1.23, 0.05 and 6.28μg·L^-1 respectively in the sea water, 20.0×10^-6 , 39.5×10^-6, 0.07×10^-6 and 97.3×10^-6 respectively in the sediments, and 16.3 ×10^-6 , 0.24×10^-6, 0.38×10^-6 and 63.9×10^-6 respectively in the shellfish organisms. The results of eco-environmental quality evaluation showed that the contents of four heavy metals in the sea water were below the second degree of Sea Water Quality Standard and belonged to the grade of ＂green＂, while the contents of four metals in the sediments were all less than the values of the first degree of Standard for Marine Sediments Quality and belonged to the grade of ＂less green＂. Cu, Pb and Cd were more harmful than Zn as their potential ecological risk factors were larger; however, for the whole culture area, the potential ecological risks of heavy metals in the sediments were slight and the environmental quality of the culture areas was good. In addition, according to the standards of Pollution-free Foods, Tolerance Limit of Zinc in Foods, and Marine Biological Quality,the pollution levels of heavy metals in the four species of shellfishes had been assessed as follows. The con- centrations of Cu, Pb, Cd and Zn in Ruditapes philippinarum and Sinonovacula constricta were all below the standard values, but the content of Cu in Saccostrea cucullata Born and that of Cd in Tegillarca granosa were above the standard values.