Contamination and Health Risk Assessment of Heavy Metals in Selected Highly Edible Fish Species from Lake Nyasa, Tanzania

Heavy metal contamination emanating from increased industrial and anthropogenic activities poses considerable environmental risks to water resources, aquatic biodiversity, and human health. These metals are major sources of various unfavorable environmental changes and human health hazards. This research investigated the potential contamination level and health risk assessment of heavy metals (Fe, Zn, Ni, Cu and Cr) in five highly edible fishes (O. microlepis, C. gariepinus, O.niloticus, R. moorii,B. meridionalis) from Lake Nyasa. The results indicated that gills contained higher amounts of heavy metals compared to muscles. The levels of Fe and Zn were higher in the gills of C. gariepinus and O.niloticus than O. microlepis, R. moorii, and B. meridionalis. Similarly, amounts of Cu and Cr were higher in the gills of C. gariepinus and O. microlepis. The general trend of heavy metal concentrations accumulated in selected fish species was Fe > Zn > Ni > Cu > Cr. The amounts of heavy metals found in the fish samples were within acceptable limits set by FAO and WHO. Furthermore, the risk assessments indicated that the current exposure levels are unlikely to cause serious health risks. However, the progressive monitoring of levels of heavy metals in various aquatic organisms from Lake Nyasa is important for the continued protection of human health against hazardous health effects.