Effectiveness of Calcined Calcium Carbide Waste (CCCW) in Mitigating the Leachability of Lead and Cadmium from Contaminated Soil from Evbareke Spare Parts Market Benin City Edo State Nigeria

Abstract

Heavy metal contamination of soil can present dangers besides threats to humans as well as the ecosystem via uninterrupted intake or interaction with  contaminated soil and the food chain. The purpose of this research is to examine the effectiveness of calcined calcium carbide waste (CCCW) in mitigating  the leachability of lead and cadmium ions in contaminated soil from Evbareke spare parts market Benin City, Edo State Nigeria. Contaminated  soil samples were collected using quadrant sampling method at the depth of 0-15cm with soil auger. The calcium carbide waste was  obtained from a panel beating workshop dumpsite. The calcium carbide waste was dried to constant weight in an oven at 105^oC. 50g of the dried  calcium carbide waste (CCW) was crushed in a mortar to obtain a powdered form. The X-ray diffraction analysis for the CCCW revealed that it was made  up of predominantly portlandite (47%), calcite fraction (23.0%), dolomite (12.7%), coesite (8.6%), muscovite (4.5%) and lime (4.0%), this was corroborated  by FTIR analysis. SEM analysis revealed that CCCW possess a rough surface with pore of varied size and irregular shape. The contaminated soil from the  Evbareke spare parts market was contaminated with petroleum hydrocarbons, the soil was saline with low C.E.C. The soil texture was loamy-sand. As the  amount of CCCW amended increase in the soil, the amount of cadmium and lead ions that was releasable in the soil reduced. The cadmium and lead ions  in contaminated soil was stabilized hence reducing the cadmium and lead availability in the soil. The optimum amender amount in the  contaminated soil to immobilize lead ion was 4% w/w and ≥2% w/w for cadmium ion. The CCCW effectively mitigated the leachability of lead and  cadmium