Spent engine oil contamination from improper disposal in Nigeria introduces toxic hydrocarbons and heavy metals into soils, altering soil properties, reducing crop growth and yield, and potentially affecting the nutritional, phytochemical, and antimicrobial qualities of crops such as maize (Zea mays) and fluted pumpkin (Telfairia occidentalis). This study evaluated the impacts of waste engine oil on the proximate, phytochemical, and antibacterial activity of Telfairia occidentalis and Zea mays. The seeds were obtained in Benin City, Nigeria, and grown in humus soil that was mixed with spent engine oil that was obtained in a local mechanic workshop. Plant samples were harvested, processed and exposed to aqueous extraction after 21 days of growth. Based on the selected pathogenic organisms, the zone of inhibition method was used to determine antibacterial activity. It was found that the extracts at higher concentrations (80 g/100 ml) had the best antibacterial activity against all the organisms tested including those of E. coli, Staphylococcus aureus, Streptococcus, Pseudomonas aeruginosa, Proteus mirabilis and Klebsiella pneumoniae. The proximate analysis showed that lipid was the greatest (18% - 36.6%), then protein (0.175% - 5.425%).Phytochemical analysis showed that the amounts of alkaloids, saponins, flavonoids, and phenols were higher in the control plants and the amounts of these bioactive compounds were considerably decreased with the escalation of oil contamination (particularly 500 ml). Morphology also indicated retarded growth in polluted plants. On the whole, waste engine oil has a detrimental influence on plant growth and biochemical structure, but significant antibacterial activity is maintained at a higher extract concentration.
Imarhobobhor et al. (Mon,) studied this question.