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为了解珠江口沉积物中重金属的污染现状及潜在生态危害,于2012年5月在珠江口海域采集29个站位表层沉积物,对6种重金属(Cr、Cu、Zn、As、Cd、Pb)的含量、形态特征、影响因素以及潜在生态风险进行了研究。本研究采用改进BCR提取法分析重金属赋存形态,并运用酸提取态百分含量风险评估法对重金属潜在生态风险进行评价。结果表明,珠江口沉积物中重金属总量呈现西北向东南逐渐减小的分布特征,西岸的浓度普遍高于东岸区域,重金属含量高值区主要分布于虎门、磨刀门、鸡啼门附近,陆源人为污染影响明显;重金属赋存形态中Cr、Cu、Zn、As主要以残渣态存在,Pb主要以可还原态存在,Cd主要以酸提取态存在,各重金属非残渣态所占比例以Cd最高,表明Cd的迁移性最强;以酸提取态百分含量为依据进行的珠江口沉积物重金属的风险评价,结果显示虽然Cd的绝对含量不高,但其潜在危害等级为高风险,其余重金属为中-低-无风险等级。
In order to understand the status of heavy metal pollution in the sediments of the Pearl River estuary and its potential ecological risk, 29 stations of surface sediments were collected from the Pearl River Estuary in May 2012, and six heavy metals (Cr, Cu, Zn, As, Cd, Pb ) Content, morphological characteristics, influencing factors and potential ecological risk were studied. In this study, the improved BCR extraction method was used to analyze the occurrence patterns of heavy metals, and the potential ecological risk of heavy metals was evaluated by using the acid content percentage risk assessment method. The results showed that the total amount of heavy metals in the sediments from the Pearl River estuary showed a decreasing distribution from northwest to southeast. The concentrations in the west coast were generally higher than those in the east coast. The areas with high contents of heavy metals were mainly distributed in Humen, Modaomen, Jitianmen , And terrigenous man-made pollution was obvious. Cr, Cu, Zn, As were mainly in the residual state in heavy metal speciation. Pb mainly existed in reducible state. Cd mainly existed in acid state. The proportions of non-residual heavy metals Cd was the highest, indicating the strongest mobility of Cd. The risk assessment of heavy metals in sediments from the Pearl River Estuary based on the percentages of acid extract showed that although the absolute content of Cd was not high, the potential hazard level was high risk, The remaining heavy metals in the - low - risk-free rating.