Assessment of heavy metal content in Bernam River catchment, Selangor, Malaysia

Rivers are important for residential needs, agriculture, and hydroelectric power generation. This study focuses on the Bernam River, which serves as a water source for Selangor and Perak States residents, located on the boundary between the two states. Sampling was conducted from December 2021 to June 2022, measuring heavy metal concentrations at eleven selected sampling locations along the Bernam River and its tributaries, including the Bil River, Slim River, Dara River, Trolak River, Selisik River, and Inki River. Using the Metal Index (MI) and cluster analysis (CA), the levels of six heavy metals, which are Al, Zn, Mn, Cr, Cu, and Ni were assessed, yielding concentrations in the order of Zn > Al > Mn > Cu > Ni > Cr. The Inki River (ST1) exhibited the lowest MI level of 1.23, indicating minimal heavy metal influence, while ST11 recorded the highest MI of 6.26, suggesting significant contamination in the Bernam River at that location. The upper section of the river (ST1 to ST4) showed minimal impacts, while ST5, ST6, and ST9 exhibited significantly higher values. ST7 and ST8 showed minimal contamination, whereas ST10 and ST11 showed high contamination. This assessment reveals a progressive degradation of water quality in the Bernam River as it approaches its mouth, largely driven by human activities and seasonal factors in the surrounding area. This study will provide valuable baseline data for future research.