Physicochemical Parameters and Heavy Metals Content of Soil Samples from Farms in Minna

Abstract

Physico-chemical properties and heavy metals content of soils were determined from seven farms in Minna, central Nigeria. Conventional analytical methods were employed to determine the physico-chemical properties and the heavy metals were analysed by atomic absorption spectrometry. The result showed that pH values ranged from 6.64 - 7.70 indicating slight acidity to slight alkalinity of the soils. The total organic carbon values ranged from 0.95-2.25 % resulting in the presence of organic matter (1.63-3.87). The electrical conductivity values ranged from 17-37 μS/cm. The cation exchange capacity of the soil samples ranged from 3.68-5.15 cmol/kg. The heavy metals levels were in the following range: Cd (0.00018-0.00134 mg/g), Cu (0.0069-0.0476 mg/g), Fe (1.942-2.2059 mg/g), Mn (0.1825-0.3696 mg/g), Ni (0.0065-0.0069 mg/g) and Zn (0.0157-0.2252 mg/g). The concentration of the metals in the soil samples varied according to the following trend: Fe>Mn>Zn> Cu>Ni>Cd. The average concentration of all the metals in each farm also gave the trend Farm B>Farm G>Farm E>Farm C>Farm F>Farm D>Farm A. The findings indicate the presence of heavy metals in all the farms but only Fe was above the FAO/WHO standards.