巢湖表层沉积物与环棱螺重金属分布特征及生态风险评价

Heavy Metals in Surface Sediments and Bellamya of Chaohu Lake:Distribution Characteristics and Risk Assessment

以巢湖优势种淡水贝类——环棱螺与表层沉积物为研究对象,采用HNO_3-HF-HClO_4全消解法消解,然后使用电感耦合等离子体发射光谱仪(ICP-AES)对二者重金属(Cd,Cr,Cu和Pb)的总量分布进行研究,同时运用潜在生态风险指数法及单因子污染指数法与均方根综合指数评价二者重金属风险。结果表明:巢湖沉积物均已受到了一定程度的重金属Cd,Cr,Cu,Pb污染,其中以Cd的潜在生态风险最大,而环棱螺中则以Pb和Cr为高风险元素;重金属的分布特征和相关性分析显示,巢湖沉积物中的重金属来源具有相似性,而环棱螺对重金属的积累因多种环境因素的综合作用,使得环棱螺体内的重金属来源不同。因此,在未来的巢湖环境治理过程中,可着重考虑对重金属Cd,Cr,Pb的治理,同时应加大对贝类等生物监测措施的应用。

Surface sediment samples and Bellamya were taken from the Chaohu Lake.The concentration and space distribution of heavy metals （Cd,Cr,Cu and Pb） were studied by HNO_3-HF-HClO_4 digestion-ICP-AES （Inductively coupled plasma atomic emission spectrometry）.The pollution levels of the four heavy metals were evaluated by the potential ecological risk index,single factor pollution index and root mean square composite index.Results suggest that the sediments in Chaohu Lake have been polluted to a certain extent by heavy metals （Cd,Cr,Cu and Pb）,among which Cd poses the largest potential ecological risk,while Pb and Cr are the high risk elements for Bellamya.The distribution characteristics and correlation analysis of heavy metals showed that the heavy metal sources in the sediments of Chaohu Lake are of similarity; whereas the sources of heavy metals in Bellamya are different due to multiple environmental factors.In conclusion,treatments of heavy metals （Cd,Cr,Cu and Pb）should be emphasized and the application of biological monitoring mwasures to shellfish should be strengthened.