Assessment of Heavy Metal Pollution in Soils from Farms in the Vicinity of Durumi Quarry Site in Mpape, Abuja Nigeria

Seasonal concentrations of eight total and bioavailable heavy metals (Cr, Cu, Cd, Zn, Mn, Ni, Pb an Fe), along with levels of some physico chemical properties of soils in vegetable farms around the rock quarry in Durumi, Abuja were assessed in order to ascertain the level of heavy metal pollution of the soil. Control and actual soil samples were collected from depths of 0.0 -5.0cm and 5.0 - 10.0 cm during dry and rainy seasons. During dry season, mean concentrations of total heavy metals ranged from 0.02 (Cu) to 71.53(Fe) mg/kg for samples and 0.01mg/kg (Zn) to 111.89 mg/kg (Fe) for controls. During rainy season the heavy metal concentrations ranged from 0.02 mg/kg (Cu) to 22.53 mg/kg (Pb) for samples and 0.03 mg/kg (Cd) to 26.63 mg/kg (Pb) for controls. These observed concentrations were lower than the Maximum Allowable Limits (mg/Kg) for World Health Organization (WHO) and Food and Agriculture Organization (FAO). During dry season, heavy metals that indicated anthropogenic content, had anthropogenic levels that ranged from 16.67 %( Cd) to 94.00 %( Cr) for soil at depth of 0.0 – 5.0 cm and 35.25 % (Fe) to 96.28 %( Mn) for soil at depth of 5-10 cm. During rainy season the range of anthropogenic input was 25.93 %( Cd) to 81.23 %( Cr) for soils at depth of 0.0-5.0 cm and 4.21 %( Mn) to 93.21 %(Cu) for soil at depth of 5.0 – 10.0 cm. This indicated that the quarry activities influenced the concentrations of some heavy metals observed in the soils. Contamination /pollution (C/P) Index ranged from 0.0 to 0.27 levels with Pb having the highest at moderate contamination levels, indicating that the soils are not polluted. These findings show that the soil in the farms studied is not polluted by heavy metals from the quarry activities though physico chemical parameters of the soil favoured the bioavailability and mobility of heavy metals.