Surface and Ground Waters Concentrations of Metal Elements in Central Cross River State, Nigeria, and their Suitability for Fish Culture

Abstract

One of the requirements for fish farming is good water quality, void of pollutants. Some heavy metals such as Magnesium, Calcium, Zinc and Iron, which are important in daily life processes, could become pollutants above the required concentrations. Others such as Mercury (Hg), Arsenic (As), Silver (Ag), and Cadmium (Cd) are not required by organisms even at low concentrations. Surface and ground water were investigated for heavy metals concentration to establish their suitability for fish culture. Three surface water bodies (a river, stream and fish pond) and ground water stations (dugout well and two bore holes) were sampled. Heavy metals were analyzed spectrophotomically at different wave lengths. Data were collated and subjected to analysis of variance which showed that heavy metal concentration in order of abundance was pond, river, stream, dug out well and the bore holes. Heavy metals were therefore, more concentrated in surface water than in ground water (p < 0.05). Surface water contain run off from within their basins while ground water contain what has been sieved into it from the surrounding. Hardness which is a measure of Calcium (Ca) and magnesium (Mg) salts were higher in ground water compared to surface water. Heavy metal concentration were Cu = 0.06 - 0.97 mg/l, Cd = 0.0 - 0.0013 mg/l, Zn = 0.04 – 2.97 mg/l, Ni = 0.0 – 0.43 mg/l, Mn = 0.1 – 3.67 mg/l, Fe = 0.95 – 5.11 mg/l and Al = 0.02 - .02 mg/l. Though heavy metals have no safe concentration for living organisms, the metals were observed to be lower than concentrations recommended by several bodies including Food and Nutrition Board (USA) and Food and Drug Administration Control (NAFDAC in Nigeria).