Source Analysis of Heavy metals and Polycyclic Aromatic Hydrocarbons from a popular dumpsite, Lagos State, Nigeria

In this study, landfill leachates and plants from Olusosun landfill in Ojota area of Lagos State, Nigeria were investigated. Physicochemical parameters, concentrations of heavy metals (HMs – Pb, Cd, Cr, Ni, Mn and Zn) and polycyclic aromatic hydrocarbons (PAHs) were determined in leachates while HMs and PAHs were determined in plants. Perchloric and sulfuric acids mixtures were used for digesting both the leachates and plant samples prior to quantification by atomic absorption spectrometry. Cold extraction was used for extracting PAHs and quantified using gas chromatography-mass spectrometry. The range of results on HMs analysis were: leachates (mg/L) - Pb: 0.60 - 1.10, Cd: 0.04 - 0.05, Cr: 0.30 - 0.40, Ni: 0.13 - 0.19, Mn: 0.53 - 0.74 and Zn: 2.24 - 3.72; plants (mg/kg) – Pb: 1.0 – 6.0, Cd: 0.3 – 0.5, Cr: 0.0 – 4.0, Ni: 0.2 – 1.6, Mn: 10.1 – 41.2 and Zn: 0.0 – 13.2 respectively. For PAHs, the concentrations (mg/L) ranged from 0.10 - 0.24 and 0.09 - 0.31 mg/kg for leachates and plants respectively. Pearson correlation and principal component analysis identified the main sources of pollution on Olusosun landfill as anthropogenic. Proper management of the landfill is advised to prevent contamination of groundwater and surface waters.