Leachate characteristics and pollution indeces of Lapite dumpsite in Ibadan, southwestern Nigeria

Municipal solid waste dumpsites pose significant risks of environmental pollution, particularly through the infiltration of leachate into soil and groundwater systems. This research examines physico-chemical properties of leachates from the Lapite dumpsite located in Ibadan, southwestern Nigeria, and assesses its pollution indices to evaluate its effects on nearby ecosystems. The analysis of the physico-chemical characteristics and concentrations of heavy metals, including Fe, Zn, Cu, Pb, Ni, Cr, Co, Cd, and As, in leachates collected from six distinct locations within the dumpsite were done using standard analytical methods. The extent of pollution was quantified using several indices, such as the leachate pollution index (LPI), Contamination Factor (CF), Pollution Load Index (PLI), and Geo-Accumulation Index (Igeo). Principal Component Analysis (PCA) was applied to identify the primary sources of contamination. The findings indicate elevated levels of organic pollutants and heavy metals that exceed acceptable thresholds. The LPI values ranged from 43.25 to 71.25 suggesting moderate to significant pollution. Also, values of CF (0.42 – 238.00); Igeo (-1.84 – 7.30) and PLI (11.14 – 21.83) indicating critical level of pollution of heavy metals in the leachates. The PCA identified three main sources of pollution: industrial waste characterized by Fe, Zn, Cu, Pb, and Ni; soil and geogenic influences represented by Cr and Co; and residues from e-waste and pesticides including Cd and As. This study shown that the leachates have high level of contaminants, hence there is need for effective leachate management and establishment of comprehensive waste management practices to mitigate environmental and health risks.