Scientia Africana

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The evaluation of trace metal concentration in selected seafood species from new Calarbar River, in Rivers State Nigeria

T.N. Chikwe, M.C. Onojake


Three sea foods namely prawn, crab and tilapia fish from ‘new calabar river’ were assessed to determine their heavy metal concentrations as well as the health effects on the consumers. Samples were treated with concentrated trioxonitrate V and perchloric acid on a hot plate before analyzing the selected metals with an absorption spectrophotometer and flow injection mercury system (FIMS). Results obtained for crabindicated that; nickel (3.890-4.190 mg/kg), cadmium (0.007mg/kg), arsenic (0.010-0.020 mg/kg), lead (3.270-3.310 mg/kg), vanadium (0.004 mg/kg), chromium (2.970- 3.120 mg/kg), cobalt (1.050-1.190 mg/kg) show the highest concentration of all the heavy metals analyzed compared to the other sea foods. Prawn has the least concentration of heavy metals. The concentrations of nickel, lead and chromium in the three sea foods were above World Health Organization standard, while cadmium and vanadium in the three sea foods were within World Health Organization limit. The concentrations of arsenic in prawn and tilapia fish were within acceptable standard, while that of cobalt was within acceptable limit only in prawns. The concentration of heavy metals in sea foods depends on their mode of feeding as well as their body permeability. Heavy metal contaminated fish can cause several health hazards in humans ranging from cancers, liver damage, kidney failure, bronchitis among others.

Keywords: Toxicity, ecosystem, adsorption, permeability, anthropogenic, bio-indicators, concentration

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