Assessment of heavy metal contamination from sediment and soil in the riparian zone China’s Three Gorges Reservoir

Abstract

In the Three Gorges Reservoir (TGR), sedimentation of the riparian zone has occurred over the past 10 years. However, the sediment and related environmental effects have not been explored well. In the present study, sediment and soil in situ were collected in three sites of the riparian zone in the TGR. Samples were analyzed for water content, bulk density, pH, organic matter, total nitrogen, total phosphorus, and heavy metals (As, Cr, Cu, Ni, Pb, Zn). Results revealed that, compared with soil, water content, organic matter, and total phosphorus of sediment were high while bulk density was low. Heavy metal concentrations (As, Cu, Pb, Zn) in sediment were significantly higher than those in soil. Sediment was moderately polluted by Cu and Pb, and soil was unpolluted-moderately polluted by As and Cu. Moreover, the individual and comprehensive potential ecological risk of heavy metals from both sediment and soil showed a low degree. Enrichment of nutrients and heavy metals in sediment of the riparian zone are probably of formation regime and anthropogenic activities, and could pose risks to the environment and human health. Therefore, enhanced efforts of soil and water conservation and pollution treatment in the upper stream of the Yangtze River and the TGR area should be recommended.