Heavy metal pollution and the risk from tidal flat reclamation in coastal areas of Jiangsu, China

Tidal flat is an important supplementary land resource. However, increasing tidal flat reclamation in China has resulted in severe environmental issues. Using single-metal pollution index and multi-metal Nemerow pollution index, this study aimed to evaluate the risks of heavy metal pollution among different tidal flat use types, including fish farm, farmland, pastoral land, industrial land, forest and unutilized land. The results indicated that, concentrations of all elements were higher than geochemical values; Cd posed the highest risk, followed by As and Ni. Fish farm created the highest risk, followed by farmland. Every one year increase in fish farming led to increases in sediment concentrations of Cu, Cr, Ni, Pb, Zn and As by 0.73, 1.25, 0.68, 0.41, 1.22 and 0.20 mg.kg(-1), respectively. Tidal flat reclamation in Jiangsu Province creates the risk of heavy metal pollution, and specific attention should be paid to the fodders and additives used in fish farming.