Hazards due to Polycyclic Aromatic Hydrocarbons (PAHs) and heavy metals at the closed Kubang Badak landfill, Selangor

Demand on redevelopment of a closed landfill is increasing due to limited land resources. However, the hazards of a closed landfill remain unknown. Thus, there is a need to assess the health hazard for a closed landfill to ensure its suitability for future development. The aim of this study is to evaluate the distributions and hazards based on soil samples taken from a closed landfill located at Kubang Badak, Selangor, with specific focus on Polycyclic Aromatic Hydrocarbons (PAHs) and heavy metals. A total of ten soil samples were collected using hand auger. PAHs were extracted using Microwave Assisted Extraction (MAE) and analysed using Gas Chromatography-Mass Spectrometer, while heavy metals were digested with MAE and analysed using Inductively Coupled Plasma. Concentrations of PAHs were compared to guidelines from Canada, Netherlands and Denmark. Concentrations of heavy metals were compared to guidelines from United Kindom.. Results showed that 12 PAHs compounds were distributed consistently except for phenanthrene and anthracene. Most abundant was phenanthrene with an average value of 62.02 µg/kg. For heavy metals, Zn was found the most abundant ranging from 256.9–666.05 mg/kg. This is followed by Mn (29.05–262.5 mg/kg), V (3.85–174.65 mg/kg), Ga (34.4–182 mg/kg), Rb (63.7–135.8 mg/kg), Cr (37.8–136.85 mg/kg), Sr (0–158.2 mg/kg), Mg (16.1–173.6 mg/kg), Cu (0–201.6 mg/kg) and Pb (0.7–89.25 mg/kg). Two heavy metals, i.e. Cr and As were found to have concentrations above concentration limits permissible for residential activities. Whilst PAHs compounds were distributed uniformly, heavy metals were not. Based on the findings, landfill area is not suitable for residential area development as concentrations of Cr and As are above permissible limits.