大连近岸环境中重金属的分布特征及风险评价

Distributions and risk evalutionof heavy metals in Dalian coastal areas

利用电感耦合等离子体质谱仪对大连近岸海域表层海水、沉积物和贝类体内重金属含量进行了测定,分析了其分布特征及潜在生态风险。结果表明,大连近岸海域表层海水和沉积物中Zn、Cu、Cr、Cd、Pb、Hg的平均含量分别为15.2、1.21、0.59、0.13、0.104、0.038μg/L、51.8×10-6、11.2×10-6、20.4×10-6、0.07×10-6、13.5×10-6、0.021×10-6,贝类体内Zn、Cr、Cd、Pb、Hg的平均含量为108×10-6、0.36×10-6、1.25×10-6、0.11×10-6、0.016×10-6。沉积物重金属富集能力高于生物;沉积物、扇贝和牡蛎分别优先富集Pb、Cd和Zn元素。风险评价结果表明,大连近岸海水中各种重金属生态风险和贝类食用安全风险较低,但沉积物中Hg存在一定的生态风险。

The inductively coupled plasma mass spectrometry（ ICP-MS） was employed in the chemical composition analysis for the surface seawater,surface sediments and shellfishes collected from Dalian coastal areas. Based on the results,the chemical features including heavy metal contents,distribution and enrichment coefficient,and comprehensive evaluation for pollution are discussed. The mean contents of chemical elements（ Zn,Cu,Cr,Cd,Pb,Hg） were 15. 2,1. 21,0. 59,0. 13,0. 104,0. 038 μg / L in surface seawater,51. 8 × 10- 6、11. 2 × 10- 6、20. 4 × 10- 6、0. 07 × 10- 6、13. 5 × 10- 6、0. 021 × 10- 6in sediments,and 108 × 10- 6、0. 36 × 10- 6、1. 25 × 10- 6、0. 11 × 10- 6、0. 016 × 10- 6in shellfishes（ except Cu）. The enrichment capacity of heavy metals in sediments was higher than that in organisms. The heavy metal Pb had the highest enrichment in sediments while Cd and Zn could be most strongly absorbed by scallops and oysters,respectively. The result shows that the surface sediments suffered from relatively low heavy metal pollution,whereas Hg had certain potential ecological risk.