ORIGINAL ARTICLE The potential impact of leachate-contaminated groundwater of an ex-landfill site at Taman Beringin Kuala Lumpur, Malaysia Mustapha Atta • Wan Zuhairi Wan Yaacob • Othman Bin Jaafar Received: 28 February 2014 / Accepted: 2 September 2014 Ó Springer-Verlag Berlin Heidelberg 2014 Abstract Spreading of leachates to soil, surface and groundwater aquifers is a prevailing problem with unlined landfills, causing many problems with adverse impacts on the surrounding environment. The impact of leachate contamination on groundwater quality was investigated from unlined ex-landfill site at Taman Beringin in Malaysia to identify the characteristics of the groundwater, and the possible impacts on the environment. Various physico- chemical parameters including: temperature, pH, color, TDS, TSS, BOD, COD, S 2- ,F - , Cl - , NH 3 -N, SO 2À 4 , NO À 3 , and heavy metals: Ag, As, Cd, Cu, Cr 3? , Cr 6? , Fe, Hg, Ni, Pb, Zn, Mn, B, Se, Sn and Ba, were collected from four (4) monitoring wells and six (6) surface raw leachate points between December 2012 and January 2013. Physico- chemical analyses of sampled leachates and groundwater followed standard analytical methods. The results showed considerable impact of leachates on groundwater with high concentration of most chemical parameters in groundwater samples: COD (101.75 ± 99.42), BOD (28 ± 30.99), NH 3 -N (31.10 ± 19.12), F - (0.72 ± 0.32) and heavy metal; Pb (0.042 ± 0.045), Ni (0.016 ± 0.006), Fe (0.41 ± 0.68) have exceeded the Malaysian National Drinking Water Quality Standard and National Water Quality Standards CLASS II A. Remedial measures are suggested to prevent further spreading of leachates into rivers via groundwater flow. In addition, combined process of routine chemical treatment prior to biological treatment is necessary to improve the existing leachate quality to minimize the effects on the surrounding environment. Keywords Landfill leachate Á Biological oxygen demand (BOD) Á Ammonical nitrogen Á Groundwater contamination Á Water Quality Standards Introduction The degradation of waste into constituent chemicals occurs in stages in landfills and this may continue for several years even long after their closure, while they continue to pro- duce leachates and landfill gases. Spreading of leachates is however, a phenomenon that is evident around landfill without proper lining material or when lining material is punctured or leaky (Agamuthu 2001). However, some contaminants concentrations in the leachates could be present at concentrations above the appropriate standards, while some could stay high for extended period of time. These contaminants threaten groundwater resources and consequently, can pose a serious threat to human, animal and aquatic life and the deterioration of the ecosystems as a whole. Landfill design has often been one of the means of the source of groundwater pollution in Malaysia. The problems have also been aggravated from the fact that most of the existing solid waste disposal sites are practicing either open dumping or controlled tipping because the technology of proper landfill operation is not properly implemented (Chong et al. 2004). In accordance with the Eighth Malaysia Plan (2001–2005), the Department of M. Atta (&) Á W. Z. W. Yaacob Geology Programme, School of Environmental Sciences and Natural Resources, Faculty of Science and Technology, University Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia e-mail: mustapha_atta@yahoo.com O. B. Jaafar Department of Civil and Structural Engineering, Faculty of Engineering and Built Environment, University Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia 123 Environ Earth Sci DOI 10.1007/s12665-014-3675-x