Effect of Atmospheric Deposition of Pollutants on the Concentration of Trace Metals on Some Sun-Dried Food Items Dried at a Non-Vehicular Corridor in Ile-Ife Nigeria

Abstract

The effect of atmospheric pollution on some sun-dried food items in Ile-Ife, Nigeria was investigated. Six farm produce: cassava (Manihot esculenta), plantain (Musa x paradisiaca), white yam (Dioscorea rotundata), yellow yam (Dioscorea cayenensis), red cocoyam (Xanthosoma sagittifolium) and sweet potato (Ipomoea batatas) were exposed, for different hours (0 h, 8 h, 20 h, 32 h, 42 h), to the sun at a location far from vehicular activities. Exposed samples were digested and analyzed for Cu, Zn, Ni, Mn, Cd, and Pb using Atomic Absorption Spectroscopy (AAS). The concentration of Cu, in exposed samples, ranged from mg/kg in sweet potato (32 h exposure) to mg/kg in cocoyam (0 h exposure), while the concentration of Zn ranged from mg/kg in plantain (42 h exposure) to mg/kg in cocoyam (0 h exposure). On the other hand, the concentration of Mn ranged from mg/kg in plantain (42 h exposure) to mg/kg in sweet potato (0 h exposure). Furthermore, the concentration of Ni ranged from mg/kg in yellow yam (32 h exposure) to mg/kg in the plantain (32 h exposure). The concentration of Cd ranged from mg/kg in cassava (32 h exposure) to mg/kg in plantain (20 h exposure). In comparison, the concentration of Pb ranged from mg/kg in cassava (20 h exposure) to mg/kg in plantain (20 h exposure). The study observed that there was no particular pattern in the effect of atmospheric deposition of the pollutants, Cu, Zn, Ni, Mn, Cd, and Pb, on the concentration of these pollutants in the sun-dried farm products, for the different exposure hours. The study believed that the non-uniform pattern could result from differences in the concentrations of the pollutants in the atmosphere. It could also be a result of the different water retention abilities of the respective farm products, which may impact the absorption or evaporation of deposited pollutants on these farm products.