Abstract:
This research examines temporal fluctuations in leachate contamination potential at Kerawalapitiya
Waste Park, Sri Lanka's largest open waste disposal facility situated within the ecologically
significant Muthurajawela wetland ecosystem. Using the Leachate Pollution Index methodology
across three distinct seasonal periods over a comprehensive three-year monitoring campaign from
2022 to 2024, the study assessed multiple physicochemical parameters encompassing organic
pollutants, inorganic components, heavy metals, major ions, and nutrient indicators to determine
environmental contamination threats to the adjacent wetland system. Results revealed substantial
seasonal and annual variability in contamination potential, with total LPI values fluctuating around
10.0 during the 2023 wet season and 37.2 during the 2024 dry season. Organic matter emerged as
the primary pollution contributor, peaking at 80.0 during the 2024 intermediate season, while heavy
metal contamination exhibited erratic behavior with maximum levels of 43.8 recorded during the
2024 dry season. The year 2024 represented the most environmentally hazardous period, with all
measured components demonstrating elevated contamination levels. Seasonal analysis throughout
the monitoring period revealed irregular patterns, suggesting that conventional seasonal
management approaches are inadequate for addressing the complex interactions between climatic
factors, waste composition, and leachate generation processes. These findings underscore the urgent
need for enhanced monitoring protocols and adaptive pollution management strategies that can
respond to temporal variations in contamination composition, while contributing valuable insights
into leachate contamination dynamics in tropical wetland environments and informing targeted
environmental protection measures for sensitive coastal ecosystems.
