Evaluation of Bioavailable Contents of Arsenic, Copper and Zinc in Some Poultry Farms Soils in Osun State, Nigeria

This work evaluated the mobility and bioavailability of arsenic, copper and zinc in chosen poultry farmlands situated within Osun State, Nigeria in respect to the soil physico-chemical characteristics. The site was split into 12 zones of about equal sites. Soil samples were collected over a period of four months from each zone for analysis of soil physico-chemical characteristics and As, Cu and Zn contents in sequential fraction of the soil sample. Sequential fractionation of soil samples were conducted utilizing reworked Tessier technique, utilizing Flame Atomic Absorption Spectrophotometer. Mean of total content (mg/kg) and percentage bioavailability were: As 470.48±48 (31.16%), Cu 62.95±10.61 (29.02%) and Zn 125.58±20.74 (26.67%), respectively. Analysis of variance and correlation analyzes indicated that soil pH, % clay, % organic carbon, cation exchange capacity, and metal speciation in soil control metal mobility and bioavailability in the poultry farm soil. The mean contents of As, Cu and Zn in soil in the sampling area were usually more than those of the control site, indicating some degrees of contamination of the poultry farm soil by these metals. Also, the mean contents of As in some zones were considerably greater (p < 0.05) than stipulated world guidelines like Food and Agriculture Organization/World Health Organization maximum limit of 40 mg/kg in arable land. The elevated contents of As in the soil of the poultry farms in some zones and the elevated bioavailability calls attention to as this could cause a threat to the consumers of the food crops cultivated on these farms.