[A-HW28] 水循環・水環境

[AHW28-P16] Groundwater Quality at a Former Landfill Site in Kuala Lumpur, Malaysia: Contamination Levels, Health Risks, and Remediation Needs

*Wan Zuhairi Wan Yaacob¹ (1.Universiti Kebangsaan Malaysia )

キーワード：Groundwater Quality, Contamination, Former Landfill Site, Environmental Standards

This study investigates the groundwater quality at a former landfill site located in Kuala Lumpur, Malaysia, focusing on the impact of landfill leachate on aquifer chemical composition. Fourteen (14) groundwater boreholes were constructed for the groundwater study. This borehole network comprised of six (6) shallow boreholes (SBH) and eight (8) deep boreholes (DBH). Shallow boreholes were screened at 15 m depth while deep boreholes were screened at 30 m depth. Groundwater sampling was conducted after purging the wells, with strict protocols. A total of fourteen chemical parameters were analysed, revealing significant contamination levels. Results indicated that both shallow and deep groundwater samples exhibited elevated concentrations of pollutants, including Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), ammonia, heavy metals (e.g., arsenic, lead), and microbiological indicators (e.g., total coliform and E. coli), exceeding environmental standards. Shallow boreholes (SBHs) exhibited elevated levels of Total Dissolved Solids (TDS), Total Hardness, and microbiological contaminants compared to deep boreholes (DBHs). For instance, TDS levels in shallow boreholes reached up to 1800 mg/L, while deep boreholes peaked at 8280 mg/L, indicating a higher concentration of dissolved substances in deeper groundwater. Hydrochemical analysis using Piper diagrams classified the groundwater into two main facies, namely CaHCO₃ (Type I) and mixed NaKHCO₃ (Type VI). HCO₃ is a dominant anion in all groundwater samples indicating the aquifer rock type in this area is consist of limestone. Cation such as Ca is also originated from limestone (CaCO₃) chemical composition. Meanwhile, the composition of Na and K in groundwater are contributed by landfill leachate composition. Concentration spatial plots illustrated regional variations in contaminant concentrations, primarily concentrated at the northern region of the site, highlighting the urgent need for remediation efforts and continuous monitoring of groundwater quality. The findings underscore the urgent need for remediation efforts at the landfill site to mitigate the adverse effects of groundwater contamination. Immediate actions should include implementing remediation strategies to reduce contaminant levels, establishing a regular monitoring program for groundwater quality and engaging with local communities to raise awareness about potential health risks associated with contaminated groundwater.