40年来江苏石梁河水库重金属污染的沉积记录

Recent 40-year sedimentary record of heavy metal pollution in the Shilianghe Reservoir, Jiangsu Province

根据石梁河水库沉积物粒度和重金属元素(Cu,Cr,Zn,AS和Pb)含量的分析,结合137Cs放射性比活度精确定年,研究了石梁河水库沉积速率和重金属的污染变化特征,并利用地累积指数法评价了重金属的污染程度.结果表明:石梁河水库40年来平均淤积速率为3.85cm/a,Cu,Cr和Zn地累积指数一直小于1,处于轻微污染;As污染水平变化较大,现处于低水平的轻度污染;Pb污染水平自柱底始持续恶化,目前地累积指数大于1,且有污染加剧趋势.

According to the analysis of the grain size, content of heavy metals （Cu, Cr, Zn, As and Pb） and ^137Cs dating in Shilianghe Reservoir, the sedimentary rate and pollution characteristic of heavy metals were investigated, The geo-accumulation index was used to assess the pollution degree of heavy metals. It showed that the averaged sedimentary rate was 3.85cm/a, and Cu, Cr and Zn were in the light polluted level with the geo-accumulation index less than I during the past 40 years. The geo-accumulation index of As fluctuated strongly, but now it was in the light polluted level. The geo-accumulation index of Pb was more than 1, and the pollution level increased gradually from the bottom of the core and trends to aggravate.