Sediment Quality and Ecological Risk Assessment of Bera Lake

Abstract

The Bera Lake basin is a lacustrine mire system and the largest natural lake in Peninsular Malaysia. Three cores were collected from the lake sediment column in order to assess Bera Lake sediment quality and ecological risks for aquatic life and human health. An index analysis approach (Cf, Cd, Er, and IR) and the fallout 210Pb and 137Cs radioisotopes were applied to assess impacts of environmental evolutionary Changes at Bera Lake. Sediment chronology was conducted using the Constant Rate of Supply (CRS) model with the resultant sediment ages being verified by 137Cs horizons. Although the general contamination factors indicates low risk conditions in the Bera Lake basin, the risks associated with individual layers is regarded as moderate to considerable. Five deforestation phases were manifested in the dated sediment cores with distinct variations in heavy metal fluxes since 1972. These phases are in excellent agreement with the dates of land clearance and development projects undertaken over the recent decades. This study highlighted capability of contamination factors and chronological methods in environmental evolutionary studies which its catchment has extensively experienced land use changes. The destiny of fluxed heavy metal into a lake could be revealed using this methodology.