Impact of Landfill on the Physical and Chemical Properties of River Water: Evidence from Perlis, Malaysia

Abstract Sungai Kubang Tiga river, formerly a vital source of sustenance, has undergone substantial alterations in its quality which rendered it unsuitable for activities such as bathing, fishing, and agriculture. This study examined the physical and chemical characteristics of Sungai Kubang Tiga in Perlis, Malaysia, with a specific focus on pollution in the vicinity of the Tapak Pelupusan Sanitari Rimba Mas landfill. Water quality was examined at four sampling points (P1, P2, P3, P4) for turbidity, colour, temperature, total dissolved solid (TDS), pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand (COD). The study spanned from December 2023 to April 2024. The data demonstrated that turbidity and colour increased significantly during the wet season due to increased runoff. The consistent rise in colour at P4 was caused by ongoing landfill contamination. P1 and P2 showed higher pH, conductivity, and TDS levels, although P2 had higher DO levels. In contrast, P3 and P4 had higher amounts of BOD and COD. The correlation and regression analyses revealed strong positive relationships between BOD and COD. The findings underscore the substantial influence of landfill leachate on the quality of water, underlining the necessity for ongoing monitoring and efficient solutions for managing pollution.