DETERMINATION OF SOME HEAVY METALS IN DIFFERENT SPECIES OF FISH SOLD

ABSTRACT

Heavy metals are regarded as metallic elements with relatively high density having the ability to be poisonous even at low concentrations. The contamination of aquatic ecosystems by heavy metals constitute a major public health problem. Fish which is one of the most widely distributed organisms in the aquatic environment can become a source of heavy metal to humans. The aim of this study was to determine and compare the bioaccumulation of selected heavy metalsMercury, Cadmium and Lead in different species of fish sold within and around the campus of the University of Benin and other parts of Benin City. Three different fish samples were obtained from June 12, Ekosodin, BDPA and Ikpoba Hill markets. Fish samples were digested and heavy metals were analysed by using an Inductively coupled plasma mass spectrometer (ICP-MS). The results showed that Lead (μg/dl) was significantly higher in Fish samples from Ekosodin (0.191±0.18) when compared to June 12 (0.026±0.02) and BDPA (0.020±0.11). Mercury (mg/L) was significantly higher in Fish samples from Ekosodin (0.060±0.06) when compared to June 12 (0.008±0.01) and BDPA (0.006±0.003). Cadmium (mg/L) was significantly higher in Fish samples from Ekosodin (0.032±0.03) when compared to June 12 (0.004±0.003) and BDPA (0.003±0.002). Lead, Mercury and Cadmium were significantly higher in smoked fish when compared to frozen fish. Lead, Mercury and Cadmium were also significantly higher in the head of fish when compared to the fin. The above results were all statistically significant at (p<0.05). The concentration of Lead, Cadmium and Mercury were higher in the fish from Ekosodin and Ikpoba hill market. The varying degrees of heavy metal contamination detected in smoked fish from the study areas calls for an urgent need for further investigation and vigorous enforcement of regulated standards. The observed increasing high levels of heavy metals in this study could be attributed to anthropogenic sources such as fossil fuel consumption, indiscriminate disposal of domestic waste and industrial effluents on land and water bodies and other human activities.