Spatial and temporal variations of trace metals in sediments from the artificial Saemangeum Lake, Korea

Abstract

Trace metals in the surface sediments were measured to investigate the spatial distribution and annual variations of metals (Cr, Co, Ni, Cu, Zn, As, Cd, Pb, Hg) and to evaluate the pollution status for metals from the artificial Saemangeum Lake that was created by the dike construction. The highest concentrations of metals were found in the river mouth and metal concentrations gradually decreased toward the dike. Anthropogenic pollution sources from two rivers exist, while the clay fraction of sediment and TOC were found to be major controlling factor on metal concentrations such as Cu, Zn, As, Pb and Hg. Results of annual variations during 2002-2010 showed that metal concentrations increased after the completion of the dike in 2006. This indicates that the dike construction lead to increased metal concentrations in sediments due to the limited water exchange, the reduction of water current velocity and the changes of redox condition, especially developing suboxic condition in bottom water after the dike construction. Assessment of pollution status for metals indicates that Saemangeum Lake was characterized as unpolluted to moderately contaminated. Even though the lake is presently unpolluted, on-going reclamation of land for residential and industrial purposes might lead to serious contamination by various pollutants. Proper management for sustainable development should be necessary to prevent metal pollution in study area.