M.A. Adeyeye^1,, F.A. Akeredolu¹, J.A. Sonibare¹, E.L. Odekanle¹, D.D. Ajala¹

Particulate matter (PM) in ambient air is a potential carrier of toxic metals. This study determined the concentration of total suspended particulate matter in the ambient air of a secondary steel smelting plant and further determined the level of selected metals in the collected samples. Deposition gauges were installed at four distinct sampling locations in the vicinity of the plant for collection of ambient particles. The particulate samples were collected simultaneously and removed at two weeks interval from October, 2015 to April, 2016. Particulate matter from solution was recovered through Whatmann filter paper by filtration. All samples were digested and analyzed by Flame Atomic Absorption Spectrophotometry (FAAS) instrument. The elements analyzed included Copper (Cu), Iron (Fe), Nickel (Ni), Zinc (Zn), Manganese (Mn) and Chromium (Cr). The ambient concentration of ambient particulate matter was in the range of 390-1450 µg/m³ with an overall average of 918.0±325.5. This average concentration significantly exceeded the allowable limits of 150 µg/m³ set by the World Health Organisation and 250 µg/m³ by Federal Ministry of Environment of Nigeria. Analysis of the total suspended particulate matter shows the concentration (µg/m³) range of 0.1-24 for Cu, 2.3-500 for Fe, 0-3 for Ni, 11-540 for Zn, 11-120 Mn and 0-6 for Cr. The upper limit for Cu was above the values in literature. The results suggest the need to install particulate matter control device to curb the release of particulate matter into the area for adequate air quality management.

particulate matter, ambient air, heavy metals, metal recycling, FAAS