The level of heavy metal pollution in the soil as affected by wastes from pig production in Assin South District, Ghana

Abstract

Pig wastes have been considered a source of heavy metal pollution in soils in pig production communities in Ghana. The study was conducted to determine the pollution levels of copper (Cu), iron (Fe) and zinc (Zn) in soils in some pig production communities in Assin South District. Soils and pig droppings from five pig waste dumping sites designated as NS, AM, AK, AD and NK and one non-dumping site,O, (control) were studied. The mean Cu concentration in the droppings varied from 12 mg kg-1 to 46 mg kg-1 and in the order of NKAM NS AK AD. The mean Fe concentration in the droppings also ranged from 551 mg kg-1 to 657 mg kg-1 whilst the Zn concentration ranged from 55 mg kg-1 to 118 mg kg-1 and in the order of AD AM NS NK AK and NS NK AM AK AD respectively. The mean concentrations of extractable Cu, Fe and Zn in the soils from all the dumping sites were significantly (P ≤ 0.05) higher than the background value (control). The mean Cu concentration in the soils varied from 49 mg kg-1 to 70 mg kg-1, whilst the Fe varied from 957 mg kg-1 to 1020 mg kg-1 and the Zn varied from 108 mg kg-1 to 204 mg kg-1, and the order of the variations differed from that of the pig droppings. The results of the quantification of the metal contamination in the soils from the dumping sites using geoaccumulation index indicated that at all the sites, the Cu pollution in the soils was moderate, the soils were almost not polluted by Fe, and the Zn pollution was light