Application of multiple ecological risk indices for the evaluation of heavy metal contamination in a coastal dredging area

Toxic compounds such as heavy metals exert chronic and lethal effects in animals and plants. There is a need to analyze the contamination level and the biological effect rather than to simply compare the heavy metal contents. Heavy metal contamination in sediments from Masan Bay were evaluated by multiple ecological risk indices before and after a sediment dredging process. The results concluded that heavy metal contamination in sediments of Masan Bay was at a `heavily polluted levelʹ by sediment quality guidelines and `biological effects ranged between low and median (ERL-ERM)ʹ by guidelines for adverse biological effects both before and after dredging. Concentrations between effect range low and median (ERL-ERM) represent a possible-effects range within which effects would occasionally occur. Although the guidelines were derived from biological and chemical data of nearly 350 publications, the change resulting from the dredging process was not well distinguished by this method. This is because of wide ranges between ERL and ERM. The analysis by the degree of contamination (Cd) was best represented for evaluating the effect of sediment dredging. In addition, metplate which is a test kit utilizing β-galactosidase of E. coli was also applied to the sediments.