三沙湾表层沉积物中重金属赋存形态及环境风险评价

Speciation and environmental risk assessment of heavy metals in the surface sediment of Sansha Bay

利用BCR四步分级提取法分析三沙湾表层沉积物中6种重金属(Cr、Co、Ni、Cu、Zn、Pb)不同赋存形态的含量,阐述了重金属赋存形态与其环境因子关系,并采用次生相与原生相分布比法(RSP)和潜在生态危害指数法评价沉积物中重金属环境风险程度。结果表明,Pb主要以铁锰氧化物结合态为主,其他重金属以残渣态为主。重金属Co、Ni、Cu、Cr相互之间呈显著正相关,Pb与Zn呈显著正相关,有机碳与Co、Ni、Cu、Cr、Zn呈显著正相关。评价结果显示Pb总体表现为中度污染,具有中等环境风险,其他重金属为无污染到轻度污染,环境风险较低。

BCR four stages sequential extraction procedure was applied to investigate the speciation and contents of six types of heavy metals(including Cr,Co,Ni,Cu,Zn and Pb)in the surface sediments in Sansha Bay.The relationships between the speciation of these heavy metals and other environmental factors were described.The environmental risk of heavy metals was evaluated by the ratio of secondary phase to primary phase(RSP)and the contamination and potential ecological risk.The results showed that the Pb existed mainly in Fe-Mn oxide faction,and others existed mainly in residual fraction.Co,Ni,Cu,and Cr were significantly positively correlated with each other,and also with Pb and Zn.And the organic matter was significantly positively correlated with Co,Ni,Cu,Cr and Zn.The assessment results showed that Pb was generally at the middle pollution level,which might pose middle environmental risk,while other elements were at clean to light pollution level,whose environmental risk was low.