晋江感潮河段沉积物重金属赋存形态及潜在生态风险

测定了晋江感潮河段表层沉积物中12种重金属的含量,分析了沉积物中重金属的分布特征,结果显示:Cr、Ni、Cu、Zn在受人类活动影响较大的中间河段偏高,远离城区与工业区的上游、水动力条件较好的下游偏低。用改进的BCR四步提取法分析了4个站位沉积物中重金属的赋存形态,结果表明:Mn、Cd的弱酸溶态和Pb、Cu的可还原态占主导地位,具有较大的潜在生态危险性;V、Sb、Ti、Sn主要以残渣态为主,对环境的危害较小。沉积物中重金属污染的潜在生态风险评价表明,Cd污染及其生态危害性非常严重,Cu、Zn、Pb、Cr和Ni污染较轻。总体上,晋江感潮河段表层沉积物已受重金属严重污染,属于生态危害性极强的重污染水平。

SPECIATION AND POTENTIAL ECOLOGICAL RISK OF HEAVY METALS IN SEDIMENTS FROM TIDAL REACHES OF THE JINJIANG RIVER

The concentrations of 12 kinds of heavy metals in the surface sediments from tidal reach of Jinjiang River were determined in this paper.The results show that the distribution of Cr,Ni,Cu,Zn are higher at the middle of the river,but lower at the beginning and the end of the tidal reach of Jinjiang River.A modified BCR four-step sequential extraction procedure was carried out to obtain the speciation fractionation of heavy metals in the sediments from 4 stations.The results show that Mn、Cd are present at comparatively higher percentages in the acid extractable fractions and Pb、Cu relatively higher in the reductive fractions,meaning that these metals present larger potential danger.The highest percentages of V、Sb、Ti and Sn were found in the residual fractions,meaning they were less harmful to the environment.Assessment using potential ecological risk indices of heavy metals indicates that the pollution degree and ecological risk of Cd appears highest among all these heavy metals in surface sediments and that of Cu、Zn、Pb、Cr and Ni lower;the pollution degree of surface sediments of tidal reach in Jinjiang River is more serious,and belongs to the extremely stronger ecological risk level.