HEAVY METAL CONTAMINATION OF FISH SOLD AT NIGERIA’S RIVERINE AND COASTLINE MARKETS: AN OBSERVATIONAL VIEW STUDY

Fish constitutes a very important source of protein in the diet of many Nigerians hence occupying an important segment of the food chain. The fish sold at Nigeria’s riverine and coastal markets is usually obtained from those nearby bodies of water and the safety of these fishes for human consumption becomes mandatory to prevent various human diseases. This review perspective paper looked at the level of Heavy Metal (HM) contamination of fishes sold at Nigeria’s riverine and coastal markets. Data was obtained from Calabar, Port Harcourt, Lagos, Onitsha, Asaba, Abeokuta, Warri, and Badagry and 57 scholarly articles met the inclusion criteria. Contamination of fishes with the following HMs was analysed: Lead (Pb), Cadmium (Cd), Zinc (Zn), Copper(Cu), Iron (Fe), Nickel (Ni), Chromium (Cr), Antimony (Sb), Mercury (Hg), Arsenic (As), Cobalt (Co), Aluminum (Al), Vanadium (V), Selenium (Se), and Silver (Ag). Analysis of the data showed that HMs that contaminated fishes most were Pb (70.18%, n=40), Cd (61.40%, n=35), Zn (59.65%, n=34), Cu (54.39%, n=31) and Fe (54.39%, n=31); and HMs with bioaccumulation in fishes above the FAO/WHO maximum thresholds were Pb (62.50%, n=40), Fe (54.84%, n=31), Cu (38.71%, n=31), Cd (37.14%, n=35) and Cr (36.00%, n=25) and hence toxic for human consumption. Fish contamination is bound to be on the increase and lack of appropriate knowledge by people on solid wastes disposal is generally seen as the major cause of soil, water and fish contamination with HMs. There is therefore need for more sensitization and creation of more public awareness on dangers of indiscriminate solid wastes disposal on our soils, water and fishes. Also, laws governing wastes management in cities and towns should be strengthened, and strictly implemented with stiff penalties for offenders to serve as deterrent.