ASSESSMENT OF HEAVY METAL LEVELS IN JUJI RIVER WATER AND CATCHMENT SOIL IN KADUNA CITY, NIGERIA

Abstract

The levels of cadmium (Cd), copper (Cu), lead (Pb), and chromium (Cr) in water from Juji River and its catchment soil (a valley popularly known for vegetable farming) in Kaduna City, Nigeria, were assessed. Water and soil samples were collected from four different points at two depths (0 – 15 cm; 15 – 30 cm), analyzed for routine attributes and metal concentrations using standard operating procedure. The results indicated that the ranges of metal concentrations in water (mg/L) were: Cr (213±0.867 to 0.098±0.001), Pb (0.092±0.023 to 0.101±0.064), Cu (0.015±0.007 to 0.013±0.005) mg/L. The concentration of Cd at all sampling points was below detection limit of 0.01 mg/L; while that of Pb exceeded the drinking water limit of 0.01 mg/L. Soil analysis indicated that metal concentrations (mg/kg) were highest at the top soil and decreased with depth. Pb had the highest concentration of (20.65±1.201); which did not exceed the maximum limit of 200 mg/kg for soils. Cr had maximum and minimum concentrations of (401.13±120.90) and (174.505±143.27) mg/kg, respectively, with most of samples exceeding the permissible limit of 200 mg/kg. The maximum and minimum concentrations of Cu were (19.056±2.881) and (4.514±1.712) mg/kg, respectively, lower than the permissible limit of 100 mg/kg. Cd concentrations at all sampling points were lower than the permissible concentration of 100 mg/kg in soils. The presence of heavy metals in the sampled soil and water portends their transfer to the food chain, especially as crop and vegetable cultivation in these valleys.  Keywords: Heavy metal, soil, water, Juji River, vegetable farming