Trace Metals’ Contamination of Stream Water and Irrigated Crop at Naraguta-Jos, Nigeria

摘要

The concentrations of trace elements Chromium (Cr), Cadmium (Cd), and Lead (Pb) in stream water and irrigated crop Carrots ( Daucus carota sativa ) in Naraguta area of Jos were determined. The stream water was sampled at three different sites A, B and C which were about 200m apart along the stream. The Daucus carota sativa were sampled from a farm at the bank of the stream around Site C. The trace metals were analysed with Atomic Absorption Spectrophotometer (Buck Scientific 200A model). The mean concentrations of Cr, Cd and Pb in the stream water were between 0.008mg/l – 0.440mg/L, 0.002mg/L – 0.138mg/L and 0.000mg/L – 0.404mg/L for sites A, B, C. respectively. The concentrations of these metals in Daucus carota sativa collected at site C were Cr = 0.02mg/kg, Cd = 0.042mg/kg and Pb = 0.404mg/kg. The concentrations of the heavy metals in water and Daucus carota sativa in some of the sites were beyond threshold limits set by the Federal Environmental Protection Agency (FEPA) and the World Health Organization (WHO). Therefore, water and Daucus Carota sativa obtained from these sites were unsafe for human consumption as they pose serious health risks due to contamination with the metals. For environmental sustainability the management strategies suggested includes proper treatment of effluents discharged into the stream and adoption of good farming practices by farmers through proper soil amendment and selection of crop varieties with lower metal absorbability. Key words: Heavy metals, Water, Carrots, Limit, Naraguta