重庆市城镇河流沉积物重金属污染的潜在生物毒性评价

Potential Biological Toxicity Assessment on the Pollution of Heavy Metals in Fluvial Sediment in Chongqing

目的了解重庆市区城镇河流水体沉积物重金属的污染状况并评价其潜在生物毒性。方法于2006年12月，在重庆市区的河流（包括长江和嘉陵江）设置3个断面（两江汇合前的长江珊瑚坝断面与嘉陵江观音桥断面、两江汇合后的广阳坝断面），在每个采样断面采集0．10cm与10～20cm沉积物样品，采用电感耦合等离子体原子发射光谱法（ICP—AES）测定样品中Cu、Pb、Zn、Cr元素的含量，分别采用地积累指数法（Igeo）和沉积物质量基准法（SQG）对沉积物重金属的污染状况和潜在生物毒性进行评价。结果沉积物中Cu的Igeo值大多在2．4～3．0之间，达中度到偏重度污染，沉积物中Cu的潜在生物毒性远远大于其余3种重金属元素，沉积物中Pb、Zn、Cr基本处于清洁级；Pb、Zn、Cu、Cr与Fe均未显示出正相关，表明这些重金属元素主要来源于人为污染源。结论本次调查的重庆市城镇河流沉积物中Cu的污染程度和潜在生物毒性最大，而沉积物中Pb、Zn、Cr基本上不存在潜在生物毒性。

Objective To know the pollution degree and to evaluate the biological toxicity risk of heavy metals in the sediment in Chongqing section of Yangtze river. Methods In December, 2006, the surface sediment （0 to 10 and 10 to 20 cm） samples were collected in three sampling sections. The contents of Cu, Pb, Zn, Cr were determined using ICP-AES. The pollution degree and the biological toxicity risk of heavy metals in the fluvial sediment were assessed with the application of the geoaccumulationindex （Igeo） and the sediment quality guidelines （SQGs）, respectively. Results The Igeo value of Cu in the sediment in Chongqing section of Yangtze river was 2.4-3.0 implying the moderately to strongly contaminated degree. The biological toxicity risk of Cu in the sediment was much more higher than those of other elements. The I~ values of contents of Pb,Zn,Cr in the sediments basically accord with the clean level .The contents of Cu, Pb, Zn, Cr in the sediments were negetively correlated with the content of Fe. Conclusion The content of copper in the sediment of the Chongqing section of Yangtze river reveals serious biological toxicity risk ,the contents of Pb,Zn,Cr in the sediments present less biological toxicity risk in a certain degree.