Heavy metals accumulation in river sediments of Chongming Island, Shanghai City, and its environmental risk

Heavy metals accumulation in river sediments can reflect the environmental quality of river waters. It's of practical significance to study the accumulation level of heavy metals in river sediments and its environmental risk. In this paper, the heavy metals accumulation in river sediments of three typical towns of Chongming Island was studied, and the results showed that the average accumulation of Zn, Cr, Cu, Pb and Cd in Chengqiao Town, Baozhen Town and Chenjia Town was 103.1, 79.2, 39.0, 29.7 and 0.300 mg · kg^-1, 99.0, 104.0, 50.5, 32.7 and 0.308 mg · kg^-1, and 86.7, 79.5, 32.2, 30.5 and 0.274 mg · kg^-1, respectively. In South Chongming, the average accumulation of Zn, Cr, Cu, Pb and Cd was 94.72, 81.35, 38.52, 30.78 and 0.297 mg · kg^-1, respectively. The environmental risk assessment by using geoaccumulation index (I_geo) indicated that these three towns had a low-medium rank environmental risk of heavy metals accumulation in river sediments, and the probability of achieving medium rank risk was in the order of Chengqiao > Baozhen > Chenjia.