Heavy Metal Status of Major Vegetable Farmsoils in Ilorin Metropolis, Kwara State, Nigeria

Abstract

Soils in developing areas have been confirmed by researchers to be contaminated with heavy metals which are a major category of pollutants. Previous projects had been carried out to ascertain different levels of heavy metals in soils but this paper targets heavy metals and degree of pollution of major vegetable farm soils in Ilorin metropolis, Kwara State, Northern Nigeria. Therefore, this work aimed at determining the; concentrations of total heavy metals (HMs) and the pollution index of the major vegetable farm soils. Total cadmium (Cd), copper (Cu) and lead (Pb) in soils were determined by acid digestion and Atomic Absorption Spectrophotometry method. Data generated were subjected to Analysis of Variance (ANOVA) and mean separated using Duncan Multiple Range Test (DMRT) at 5% significance. HMs in soils were: Cd (0.00-4.67), Cu (1.71-30.08) and Pb (1.29-82.00) mg/kg with pH range of 6.62-9.33 and pollution index range of Cd (0.00-2.90), Cu (0.86- 11.72) and Pb (0.70-14.30). Some soils showed elevated concentration of Cd and Pb higher than the recommended permissible – limit (Cd=1.00 mg/kg, Pb=70.00mg/kg) with pollution index of HMs ranged from low pollution to very strong pollution (0.00±0.00- 14.30±1.77). The study therefore, suggested that there could be a risk of Cd and Pb associated diseases on the consumption of vegetables planted on some of these soils. Keywords: Heavy metal content, pollution index, vegetable farmsoils, Ilorin metropolis.