Analysis of heavy metals in the surface sediments of shallow lakes in Nanjishan (Poyang Lake) Natural Wetland in China

Aim: The land between aquatic and terrestrial systems is defined as wetland where heavy metals accumulate and deposit in sediments more easily due to natural as well as anthropogenic activities. The main objective of the present study was to investigate the distribution characteristics, pollution degree and potential source of heavy metals in the surface sediments of Nanjishan Wetland Nature Reserve. Methodology: Surface sediments samples from three representative shallow lakes (Lake Nanshen, Lake Dong and Lake Chang) were collected, and heavy metals were estimated in terms of content characteristics, spatial features and correlations. Integrated pollution indexs (PI and IPI), geoaccumulation indices (Igeo) combined with geostatistical methods were used to calculate the degree of heavy metals, evaluate the ecosystem risks and identify the potential sources. Results: Indicators like PI, IPI and Igeo indicated that heavy metals in research areas exist widely and were mainly dominated by Zn, Pb, Cd and Cr at higher concentration than the permissible limit standards. Statistical analysis revealed two main sources of pollutants; first due to discharge of mixed-origin domestic wastewater emissions and other due to terrigenous? sediments. Interpretation: Human activities, such as traffic, aquaculture, municipal and industrial wastewater and hydrological exchange can significantly influence the spatial variation of heavy metals in wetlands.