Heavy Metals Contamination of Soil and Water From an E-Waste Burning Site, Ojota, Lagos

ABSTRACT

The objective of this study is to determine the level of heavy metal contamination in soil and water at an E-waste burning site at Ojota, New garage in Lagos State, Nigeria. The information obtained from this study will form the basis of formulating strategies for the environmentally
sound management of e-waste in Nigeria. Systematic grid sampling design was used in this study in sampling the soil and ash samples. Physico-chemical parameters such as the pH, soil organic matter, organic carbon and cation exchange capacity were determination. The assessment of the level of Cu, Zn, Cr, Mn, Pb and Cd in the ash, soil and water from the e-waste burning site using Atomic Absorption Spectroscopy reveal that the site is highly contaminated. The mean concentration of Cu, Zn, Cr, Pb, Mn, and Cd of depth 0-30cm in site A were determined to be 260.75 mg/kg, 242.75 mg/kg, 247.75 mg/kg, 1,120 mg/kg and 37.5mg/kg respectively while that of site B were determined to be 153.5 mg/kg, 104.5 mg/kg, 41.75 mg/kg, 278 mg/kg and 22.25 mg/kg respectively. Cadmium was not detected in the samples which may be due to the proper recycling of cadmium materials or the banning of Cd-Ni battery in most countries due to its toxicity. The level of metal recorded in the control taken from Yabatech Botanical Garden was lower compared to the burning site which shows that e-waste burning at Ojota site contributed to the increase in the concentration of the heavy metals in the soil leading to the contamination of the site. The well water from this site was contaminated with lead of concentration of 0.17 mg/L and 0.20 mg/L and also with chromium of concentration 0.13 mg/L and 0.12mg/L respectively. This is as a result of the leaching of the metals into the groundwater contaminating the well water. The information obtained from this study shows that the soil and water at the E-waste burning site at Ojota, New garage in Lagos State, Nigeria is highly contaminated and appropriate method should therefore be adopted to reduce their effects.