An assessment of mercury contamination and the relationship between environmental variables and mercury concentrations in a seasonal wetland

Abstract

A study was undertaken to assess the extent of mercury contamination in the water and sediment in a seasonal wetland, as well as to determine the relationship between environmental parameters and the distribution of the mercury contamination. Water and sediment samples were collected and analysed for methylmercury, inorganic mercury and other physical and chemical variables. One-way analysis of variance and homogeneity of variance were performed, and linear regression analysis was used to determine correlations between mercury and other environmental variables. The highest mercury concentrations were recorded at the sites located closest to the industrial complex. Methylmercury concentrations in the water and sediment were mostly higher during the low flow season, while inorganic mercury concentrations in the water and sediment were higher during the high flow and low flow seasons, respectively. Chromium, manganese, organic carbon and fine sediment particles were found to have significantly positive correlations with mercury concentrations in water and sediment. It was also found that the mercury concentrations decreased within a relatively short distance from the sites closer to the industrial complex to the sites further downstream