河流底泥砷污染状况及分布特征研究

The Study of the Pollution Situation and Distribution Characteristics of Arsenic in Sludge of the Creek

为了今年马鞍山市河湖整治重点工程中清淤工程环境安全需要，对该市城郊某河全流域不同断面底泥中砷含量进行了分析，评价了底泥砷污染状况并分析了该河流底泥中砷的沿程分布特征、横向分布特征和垂向分布特征。结果表明，该河流底泥砷含量范围为17．9～335mg／kg，均值为94．25mg／kg。参照土壤环境质量标准三级标准值对底泥中砷含量进行评价，平均砷污染指数2．69为中度污染；用土壤背景值标准参照评价，平均砷污染指数为9．72，超过当地背景值水平8．50倍，该河流从上游到下游，总体上沿程底泥砷含量未呈明显变化，但局部域段呈现一定变化趋势；断面横向分布上，河中间砷含量总体高于河岸边；垂向分布上，表层底泥砷含量最高。

In order to satisfy the needs of environmental safety for removing sludge in the major project--＂ Creek and Lake Treatment＂ in Ma Anshan in 2009. We determined the concentrations of total As in sludge of deferent along the whole creek in Ma Anshan suburb, evaluated the pollution situation of As, and discussed the longitudinal, transversal, vertical distribution of As in sludge of the creek. The results indicated that the concentration was 17.9 - 335mg/kg, the average date was 94.25mg/kg. The average As pollution indices were 2.69, referring to the China National Standard for soil Environment Quality Grade III, the sludge was moderate - polluted; and the average As pollution indices was 9.72 referring to soil background values, and was 8.50 times more than local As background values. There is no obvious variation trend for As concentrations along the creek on the whole, but in some reaches of the creek, there is a certain variation trend for As concentrations in the transversal direction of section; overall, the As concentrations are higher in the sludge in the middle of the creek than the near the bank of the creek.