Geochemical Speciation and Risk Assessment of Heavy Metals in the Surface Sediments of Jemberau Lake, Tasik Chini, Malaysia

The mine tailings from the iron ore mining in Jemberau catchment, Tasik Chini is directly seeping into Laut Jemberau. The caustic red sludge which consists of trace amounts of heavy metals from the mining site is also being washed and ultimately gets accumulated in the lake sediment. Under favorable conditions, the heavy metals are remobilized to the aquatic system, causing danger to the benthic organisms. Hence, a risk assessment study of surface sediment was conducted at Laut Jemberau, Tasik Chini. The results suggested that Mn, Co, and Cd are the most easily exchangeable metals in the sediment. Among these metals, the concentration of Mn (mean value = 12.04 ppm +/- 13.25) is higher and it has adverse effect on aquatic biota. The risk assessment code (RAC) results also identified that the risk associated with Co, Cd, Mn are highly dangerous due to its high bioavailability and labiality in Jemberau aquatic system. The closer vicinity of mining site poses higher risk in comparative to other sampling stations. The geoaccumulation index (Igeo) shows that level of contamination in surface sediment due to anthropogenic activities is extremely higher especially in S2- near to mining site.