ABSTRACT

This study evaluates the impact of hydrocarbon contamination on soil heavy metal levels, as well as total and available nitrogen and phosphorus, and assesses the remediation potential of cassava mill effluent (CME). Soil samples were collected from hydrocarbon free sites and polluted with crankcase oil which was analyzed for heavy metal concentrations, total nitrogen, total phosphorus, available nitrogen, and available phosphorus.  Soil samples underwent different CME treatment frequencies; once, monthly, weekly and daily with control groups inclusive. The results demonstrate elevated levels of heavy metals in the contaminated soil, indicating potential environmental risks. Additionally, the contamination significantly affected the availability of nitrogen and phosphorus in the soil.

Subsequently, remediation experiments were conducted using CME, a readily available organic waste product. Application of CME resulted in notable reductions in heavy metal concentrations and improvements in nitrogen and phosphorus availability in the soil. These remediation effects varied with the dosage and frequency of CME application. Overall, the findings suggest that CME holds promise as a cost-effective and sustainable remediation strategy for hydrocarbon-contaminated soils, offering benefits for both heavy metal mitigation and nutrient enhancement. Further research is warranted to optimize CME application protocols and assess its long-term efficacy and environmental implications.