Heavy Metals Accumulation in Water, Sediments and Catfish (Clarias gariepinus) from Two Fishing Settlements along River Kaduna in Niger State, Nigeria

Abstract

Water, sediments and catfish (Clarias gariepinus) samples obtained from two fishing settlements along River Kaduna at Shiroro and Zungeru in Niger State, Nigeria were analyzed for some selected heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) using Buck Scientific Model 210 VGP atomic absorption spectrophotometer. The data obtained were then, analysed using one-way analysis of variance (ANOVA) statistical analysis. All heavy metals analyzed were detected in all the samples except Pb, not detected in water and catfish samples and also, Cd was not detected in sediments sample. The highest heavy metal concentrations were found in the sediments compared to the water and catfish this is because sediments are known to be major depository of metals present in the system. Zungeru fishing settlement has higher concentration of the following metals: 0.72±0.84 mg/L Fe in the water; 1331.00±46.98 mg/kg Fe and 160.83±12.18 mg/kg Zn in the catfish 7447.33±139.07 mg/kg Fe and 164.67±7.63 mg/kg Mn in the sediments than the values from Shiroro site. Shiroro fishing settlement has the highest concentration of Fe in water 5.86±0.11 mg/L, highest Fe in catfish 1482.83±99.50 mg/kg, highest in sediment 26629.50±487.97 mg/kg. The heavy metals in the water from Shiroro River follow the ranking: Fe > Cu > Cr > Zn > Mn > Cd > Ni; while the metals in the fish from Zungeru follow the order: Fe > Zn > Mn > Cr > Cu > Cd > Pb, Ni. Variable results were obtained from the two fishing settlements, but results obtained for some metals in different samples (water, catfish and sediments) were within maximum permissible limits for water, sediments and fish as recommended by WHO/USEPA, while other metals were higher than the recommended limits. Regular monitoring of these heavy metals in water, catfish and sediments on these fishing settlements is recommended.