Bioaccumulation of heavy metals in fish and shrimp from the Atlantic Ocean off the coast of Accra, Ghana, and their associated health risks

Heavy metal pollution in the environment and its bioaccumulation in biota are causes for concern, as they can have toxic effects on both biota and humans who consume them. In the present study we quantified iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) in fish and shrimp species using Atomic Absorption Spectroscopy (AAS). The fish and shrimp caught in the Nungua coastal waters of Ghana which is part of the Gulf of Guinea were Sardinella aurita, Brachydeuterus auritus, Galeoides dacadactylus, Dentex angolensis, Hemiramphus brasiliensis, Sardinella maderensis, Decapterus macarellus, Sphraena sphyraena, and Penaeus notialis. The results showed that the metal levels were highest in the shrimp (Penaeus notialis) and lowest in Sardinella aurita. There was no difference in metal levels between pelagic and demersal fish. The results indicate that the average concentrations of all metals in fish except Mn in Dentex angolensis, Sardinella aurita and Galeoides dacadactylus were within the FAO recommended levels. The Fe, Mn and Cu in the tissues of Penaeus notialis also exceeded the FAO recommended levels. The results of target hazard quotients (THQs) and total target hazard quotients (TTHQs) of the fish and shrimp also showed that all metals showed no potential health risk to consumers, as they were less than one. However, the study indicates that high and regular consumption of Penaeus notialis exposes consumers to toxic levels of heavy metals.