Assessment of Potentially Toxic Metals in Fish from Lake Manyara, Northern Tanzania

Abstract

Elemental tracer concentrations of copper, lead, nickel and zinc, were assessed in the muscles of Oreochromis amphimelas and Clarias gariepinus from Lake Manyara, Tanzania, to evaluate their safety to consumers, specifcally humans. Results revealed that no elemental concentrations exceeded the FAO permissible levels, indicating fsh from all sites are safe for human consumption. However, based on the highest found concentration of Pb, we recommend a maximum consumption of 2.2 kg of fsh from Lake Manyara per week. No signifcant diferences were observed in the metal concentrations between the two fsh species, suggesting there is no bioaccumulation in the food chain. Moreover, no signifcant diferences were found between fsh landing sites, indicating there are no regions in the lake with higher pollution. These fndings indicate that PTM concentrations have not increased to toxic levels due to increased mobilisation from the catchment. Continued monitoring of potential toxic metal concentrations in fsh is recommended due to endorheic nature of Lake Manyara and increasing anthropogenic activities in its catchment area.