Determination of Trace Metal Composition in Ambient Air from Open Burning of Solid Waste in Aiyekale, Nigeria

Abstract

Open burning of solid municipal waste uncontrolledly presents an environmental menace, which exacerbate air pollution and poses considerable health risks in most developing countries. This study aims at investigating the seasonal deposition fluxes, trace metal concentrations and determination of scavenging ratios of the identified metals, resulting from such practice in Aiyekale, Kwara State, Nigeria. The particulate matter of both dry and wet samples was collected using deposition gauges. The elemental composition of particulates collected was analyzed using Energy-Dispersive X-ray Fluorescence Spectroscopy (EDX-RF). The deposition velocity and scavenging ratio were used to study the removal mechanics of trace metal composition of the ambient air in open burning of solid waste area. The average flux rate in the wet and dry seasons was evaluated to be 3.57 × 10-6 g/m2.s, and 2.28 × 10-5 g/m2.s, respectively. For the study area, the deposition velocities for the trace metals ranged from 5.288 × 10-5 to 4.818 × 10-3 m/s while the estimated scavenging ratio was between 0.61 – 3.96 in the study area. It was obtained from the result that Au, Mn, and Zn were better removed by gravitational particle settling while Fe, Ti, and Rh were scavenged by precipitation. The results show extremely high levels of trace metals above prescribed thresholds, highlighting the need for international cooperation in resolving air quality concerns and developing regulations targeted at lowering emissions from the burning of solid waste in the study environment.