Environmental Assessment of Heavy Metals in New and Used Engine Oils: A Case Study from Benghazi, Libya
DOI:
https://doi.org/10.59992/IJSR.2026.v5n8p21الكلمات المفتاحية:
Engine Oils، Heavy Metals، AAS، Used Oil، Environmental Impact، Preventive Maintenanceالملخص
The presence of heavy metals in lubricating engine oils is a critical factor in assessing engine performance, lubricant degradation, and potential environmental impacts. This study investigated the concentrations of selected heavy metals (Pb, Cr, Ni, Cu, and Fe) in both new and used engine oils using Atomic Absorption Spectrophotometry (AAS (Engine oil samples of different brands were collected from vehicles in Benghazi, Libya, and analyzed to determine the concentrations of selected heavy metals and assess changes in physicochemical properties, including viscosity, flash point, density, and total base number.
The results showed that heavy metal concentrations were substantially higher in used oils than in new oils. Lead (Pb) concentrations increased from nearly undetectable levels in new oils to over 70 mg/kg in used oils. Similarly, chromium (Cr), nickel (Ni), copper (Cu), and iron (Fe) showed increases of more than 90% in used samples compared to new ones. These increases reflect mechanical wear, additive degradation, and contamination during engine operation. The study also highlighted marked changes in physicochemical properties between new and used oils, including decreased viscosity index, reduced flash point, and reduced sulfated ash content. Such findings confirm the diagnostic value of oil analysis for preventive maintenance, while also underlining the environmental hazards posed by improper disposal of used lubricants. This work emphasizes the urgent need for strict regulations and sustainable waste management practices in Libya and globally. Furthermore, the integration of more advanced analytical techniques, such as ICP-OES and ICP-MS, is recommended for enhanced detection accuracy in future research.
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