Evaluation of some heavy metals in wetland soils of Uguru, Yobe State, Nigeria

Abstract

Some physicochemical properties and concentrations of Pb, Fe, Cd and Zn in wetland soils of Uguru, Yobe State, Nigeria were evaluated at different locations in the study area using standard methods. Results (mean ± SD) for the soil physicochemical properties showed that pH ranged from 6.10 – 8.85, electrical conductivity (EC) ranged from 0.060 to 0.875 mScm^-1, organic carbon (OC) ranged from 1.131 – 9.428 mg/100g , Exchangeable base ranged from 2.47 – 12.80 mg/l for Ca, 0.688 – 2.416 mg/l for Na, 0.100 – 3.285mg/l for K and 0.316 – 0.849mg/l for Mg, total nitrogen (TN) ranged from 0.070 to 0.140 mg/l and available phosphorus (AP) ranged from 1.131 – 9.428 mg/100g. The concentrations of Pb, Fe, Cd and Zn ranged 0.53 – 84.95 mg/kg for Pb, 1.95 – 29.90 mg/kg for Fe, 0.13 – 24.95 mg/kg for Cd and 1.63 – 24.95mg/kg for Zn. Generally, the profile of heavy metal followed this order: Pb> Zn > Fe > Cd. Pb. However, the levels of all metals presented with exception of Cd across the sites were found within the permissible levels recommended for agricultural soils. High concentrations of Cd in some of the sites suggested a possible contamination of the farmlands.

Keywords: Wetland, Soils, Heavy Metals and Nguru