Evaluation of Heavy Metal Concentration and Health Risk Assessment in some Marine Fish Species from Zwitina Harbor Coast (Libya), as Indicator of Petroleum Pollution

As a result of industrial development, heavy metals (HMs) have become major contributors to environmental contamination worldwide. HM contamination leads to the accumulation of these metals in fish bodies. Consumption of such contaminated fish poses a serious threat to human health through the food chain. In the current study, various marine fish species were collected during the winter and summer of 2023 from four sites along the coastal region of Zwitina, Libya. The goal was to assess the levels of several heavy metals, including copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), and lead (Pb). Additionally, health risk assessment metrics were used to evaluate potential risks to human health—particularly the carcinogenic effects associated with long-term exposure to Pb and Ni, which are known to increase the risk of cancer and other chronic illnesses. Significant seasonal and regional variations in metal concentrations were observed across different fish organs. The highest concentrations of heavy metals were found in the gills of some fish species, while in others, the liver stored the highest levels. The muscle tissues exhibited the lowest concentrations of HMs. Among the studied species, Serranus scriba accumulated the highest levels of Pb, Cd, and Ni. The highest concentrations of Zn were detected in Umbrina cirrosa and S. scriba, whereas Siganus rivulatus showed the highest Cu levels. These findings suggest that bioaccumulation of heavy metals is species-dependent. Fish species that inhabit areas near sediments tend to accumulate higher metal concentrations in their bodies. For human consumption, the data showed that Cu, Zn, and Cd levels in the muscle tissues (the edible part) of the analyzed fish were within safe limits. However, Ni and Pb levels exceeded the permissible limits, posing potential health risks. The health risk assessment indicated a moderate to high likelihood of adverse health effects from HM exposure, particularly due to Pb. The calculated Hazard Index values underscore the need for ongoing monitoring and prompt public health measures to reduce the risks associated with consuming fish from contaminated waters.