Journal of Biology and Nature

Heavy metals are natural occurring minerals that are found in nature, as deposits in pure and mostly ore form. They are referred to as transition metals due their variable oxidation state, which as a result have made them to develop special properties among other elements in the periodic table. This study aimed to assess the levels of heavy metals (Lead, Chromium, Mercury, Cadmium, Iron, Zinc, Copper and Magnesium) in Clarias gariepinus and Hetrobrancus longifilis collected from the Omambala River. The fish samples were collected by fishermen at the fish landing site. The heavy metal analysis in the two fish species was studied using Atomic Absorbtion Spectrophotometer (AAS) and the instrument was calibrated with standard solutions. The result of this work showed that the highest compositions of heavy metals were:  lead (Pb) content in C. gariepinus was 2.69±1.417 mg/l while in H. longifilis was 3.14±1.395 mg/l. However, Chromium content in C. gariepinus was 3.11±0.826 mg/l and in H. longifilis was 4.04±1.073 mg/l. Mercury in C. gariepinus was 3.98±1.903 mg/l and H. longifilis  was 4.77±2.283 mg/l. Cadmium in C. gariepinus was 4.90±2.100 mg/l while  H. longifilis  was  4.83±2.019 mg/l. Moreover, Iron in C. gariepinus was 3.94±1.414 mg/l and H. longifilis was 4.31±2.077 mg/l. Zinc in C. gariepinus was 4.02±1.917 mg/l and  H. longifilis was 5.47±2.607 mg/l. Copper in C. gariepinus was 2.62±0.720 mg/l  while in H. longifilis was 3.01±0.828 mg/l. Magnesium in C. gariepinus shows 4.66±2.774 mg/l and H.longifilis shows 3.72±1.466 mg/l. The most prevalent heavy metals from the study were Zn, Cd, Hg, Mg, Fe, Cr, Pb, and Cu. It is therefore recommended that further research be made, and awareness created on the high health risk associated with frequent ingestion of these harmful mineral elements found in trace deposits in the Omambala River by the appropriate authority to ascertain their concentrations.