Metal contents in fish and crustaceans from brackish, freshwater and marine systems in South-Western Nigeria

Present study investigated trace element concentrations in either muscles or whole samples of 37 finfish and crustaceans harvested with gillnet from fresh (Olomore), marine (Eti osa) and brackish (Lekki Lagoon) waters of Ogun and Lagos states, Nigeria between June and August 2013. Trace elements were determined using ICP-MS after digestion with a microwave autoclave system. The results revealed that the general trend of trace elements in the sampled finfish and crustaceans was marine > brackish > freshwater. If all the samples are considered, 16.2% and 13.5% exceeded the 20 μg g−1 and 30 μg g−1 limits for Cu and Zn, respectively, as set by the European Union, while 71%, 50%, 79% of marine, fresh and brackish samples, respectively, exceeded the limit of 48 mg Fe per 60 kg person as set by FAO/WHO. In addition, samples exceeded the acceptable limit set by WHO/FAO, thus adequate efforts should be placed on the monitoring of effluents that are being discharged into open water bodies in Nigeria.