ONUEBUM

This study evaluated the chemistry and biological consequences of heavy metal contamination of water from River Nun at Onuebum town, Ogbia Local Government Area of Bayelsa State, Nigeria. The pH of the water, acidity, alkalinity, turbidity, sulphides, total nitrogen and total hydrocarbon content in the river water were identified. The toxicity of the water itself and that of the heavy metals in the river water were investigated using rats. Sixty rats divided into twelve groups of five rats each were used. Group A, the control rats, received distilled water only (42.86 ml/rat/day by gavage). Group B received the boiled river water. Group C received the unboiled river water. Group D received a solution of the salts of all the metal ions identified in the river water (1.24 mg Fe, 0.018 mg Cu, 0.001 mg Hg, 0.001 mg Cd, 0.001 mg Pb, 0.001mg Mn, 0.001 mg Cr/L of distilled water). Group E received a solution containing 1.24 mg Fe/L. Group F received a solution containing 0.018 mg Cu/L. Group G received a solution containing 1.24 mg Fe/L and 0.001 mg Hg/L in distilled water. Group H received a solution containing 0.001 mg Hg/L. Group I received a solution containing 0.001 mg Cr/L. Group J received a solution containing 0.001 mg Cd/L. Group K received a solution containing 0.001 mg Mn/L. Group L received a solution containing 0.001 mg Pb/L. Each rat received 42.86 ml/kg bd wt. of the appropriate solution by gavage daily, 7 days a week for 3 months. After an exposure duration of three months, there were significant increases (p ≤ 0.05) in serum urea, creatinine, chloride, LDH, total and direct bilirubin levels of the groups H (mercury only), J (cadmium only) and L (lead only) rats compared to the rats in the control and the other eight groups. There were significant increases (p ≤ 0.05) in liver GGT, LDH, total bilirubin, ALT, AST, and total protein levels of groups H (mercury only), J (cadmium only) and L (lead only) rats as compared to the control and other eight groups. There were significant increases (p ≤ 0.05) in kidney sodium, chloride, urea and creatinine levels of groups H (mercury only), J (cadmium only) and L(lead only) rats as compared to the rats in the control and other eight groups. There was also significant (p ≤ 0.05) increase in the group G when compared to control in terms of serum AST, ALT, Na+ and cholesterol levels. However, these increases were not as profound as those observed for mercury when administered singly. The adverse effects, evidenced by changes in these parameters in the test rats relative to the control group, was not observed in the groups (B and C) that consumed the river water directly. The results obtained here show that heavy metals antagonize the effects of each other when administered concurrently, a pattern of behavior which would not be evident when each is examined inisolation. The findings also show that the River Nun water, although containing several toxic
elements, may be fairly safe for human consumption.