Source Analysis of Heavy Metals and Polycyclic Aromatic Hydrocarbons from a Popular Dumpsite, Lagos State, Nigeria

Abstract

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 HMsand PAHs were determined in plants. Nitric and Perchloric acid mixtures were used for digesting bothleachates and plant samples before quantification by atomic absorption spectrometry. Cold extractionwas used for extracting PAHs and was quantified using gas chromatography-mass spectrometry. Therange 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, theconcentrations (mg/L) ranged from 0.10 - 0.24 and 0.09 - 0.31 mg/kg for leachates and plantsrespectively. Pearson correlation and principal component analysis identified the main sources ofpollution in Olusosun landfill as anthropogenic. Proper management of the landfill is advised to preventcontamination of groundwater and surface waters.