Assessment of the geo-accumulation index on the soil pollution by heavy metals in the Shuangqiao river basin

By field environment investigation and collecting soil samples in the Shuangqiao river basin, the heavy metal contents of Hg, Pb, Cd, Cr, As, Cu, Zn in the soil were analyzed, and the pollution of the soil was assessed with geo-accumulation index. The results showed that geo-accumulation index of Hg was 0.036–2.286, and 29.63% sampling sites had grade 2 degree of pollution, equivalent to moderate pollution; 68.52% sampling sites had grade 1, none to moderate pollution. Pollution of Pb was next to that of Hg, whose geo-accumulation index was 0.001–1.304 and 16.67% of sampling sites had grade 2, moderate pollution, while the other sites had grade 1, none to moderate pollution. Soil pollution of Cd, Cu and Zn was lighter, and the soil was not polluted by Cr, As. The pollution of Hg was the most serious element.