锦州湾沉积物中重金属形态特征及其潜在生态风险

用5步提取法分析了锦州湾14个样点沉积物中6种重金属的地球化学形态.结果表明,Cd主要分布在可交换态和碳酸盐结合态; Zn和Pb主要分布于碳酸盐结合态和铁锰氧化态;Cu主要分布在有机硫化物结合态;Cr、Ni主要结合于残渣态中.对Hakanson潜在生态危害指数法作了改进,结合了地球化学形态对生物毒性的影响,得出的生态风险评价结果和次生相与原生相比值法的污染评价结果类似.锦州湾西南角海域生态危害极高,产生生态危害的主要重金属污染物依次为Cd＞Zn＞Pb＞Cu.按风险等级和区域分布将锦州湾划分为4个生态风险功能分区,沿东北方向生态风险随距离增加而减弱.

Speciation characteristics and potential ecological risk of heavy metals in surface sediments of Jinzhou Bay

The speciation distribution and bioavailability of 6 metals in 14 sediment samples from Jinzhou Bay were analyzed by a sequential extraction procedure.The results showed that Cd was predominantly found in the exchangeable and carbonate phase.Pb and Zn were mainly associated with carbonate and Fe-Mn oxidation phase.Cu was higher in organic phase,and Cr and Ni were mainly associated with residual phase.Hakanson's potential risk index method is improved by the considering heavy metals biological toxicity.The results were good agreement with the assessment of RSP method.The potential ecological risk of Cd,Zn,Pb and Cu was rather high around the southwest of this bay.The order of pollution contents and ecological risk followed by Cd>Zn>Cu>Pb.The Jinzhou Bay was divided into four areas according to the degree of ecological risk,which is gradually decreased from Southwest to Northeast.