Heavy metal contamination in Lebanese lettuce: Quantification and health risk assessment

Heavy metals (HM) contamination in food products is a major risk to public health. Lebanon is constantly suffering from unresolved environmental pollution issues, which have led to an increase in atmospheric deposition of contaminants in water and soil. This study aims to investigates the levels of HM in Lettuce products collected from different market regions in Lebanon. We also estimated the potential human exposure to HM through ingestion of lettuce. We used the Atomic Absorption Spectrophotometry to determine HM levels in the collected samples. Furthermore, we calculated the Metal Pollution Index (MPI) and the Hazard Quotient (HQ) to determine the expectance of adverse health effects in comparison to other countries. The results showed that Lead (Pb), Arsenic (As) and Chromium [Cr (III)] levels in the capital city exceeded the maximum allowable values set by FAO/WHO, whereas Palladium (Pd) was above the safety limit in all collected samples. The MPIs fluctuated over all investigated regions but remained below the critical value (of 1). However, the maximum As HQ exceeded the permissible limit by 186 % and the maximum Pb HQ value was higher than that of industrialized countries including China, Brazil, and Egypt. These findings prove that regular testing and monitoring are highly required to investigate the importance of human exposure to HM in Lebanon and any associated health impacts.