Contamination of steel slag waste on industrial soils of south-western Nigeria.

• Ugwonoh^1,3, P. Maleknia¹, R. Khedhri¹, Z.F. Ali^1,4,S. Czigány²

^1,3Doctoral School of Earth Sciences, University of Pécs, Ifjúság útja 6.,7624, Pécs, Hungary.

²Institute of Geography and Earth Science, University of Pécs, Ifjúság útja 6.,7624, Pécs, Hungary.

⁴Department of Geography, Faculty of Education, Koya University, Kurdistan region, Iraq.

³Corresponding author, ugwonohnelson@gmail.com

 

Abstract

As the demand for steel production increases, there is an increase in the disposal of steel slag, which may contaminate industrial soil due to the presence of heavy metals. Hence, this study examined the contamination of steel slag waste on industrial soil in southwestern Nigeria. Sample A (steel slag specimen) was provided by African Foundries Ltd. Sample B (soil samples) was collected using a soil auger at a dumping site in an industrial area. The three representative locations are Ogijo, Ogun State; Ibadan, Oyo State; and Ikeja, Lagos State.  Sample C was a mixture of steel slag and soil. The samples were pulverized, and the chemical composition of each sample for all locations was determined using an energy-dispersive X-ray fluorescence spectrometer (ARL QUANT’X EDXRF Analyzer) at the Research and Development Laboratory of the African Foundries Laboratory, Ogijo, Ogun State. The samples were dominated by Fe₂O₃, TiO₂, SiO₂, Al₂O₃, and MgO oxides. The soil pH after slag addition increased, and the higher the slag addition, the higher the soil pH. A comparison was made between industrial soil samples (sample B) and the mixture of soil with steel slag (Sample C) using Pearson’s coefficient of correlation method. it was observed that the computed value of the Product moment correlation coefficient (r = + 0.89) of the samples for the first location falls within the table value (1 > r > 0.8) indicating that there is a strong positive linear correlation between the soil sample and the steel slag while for the other two locations the computed value of the Product moment correlation coefficient (r = + 0.77 and r = + 0.74) of the samples fall within the table value (0.8 > r > 0.4). The contamination/pollution index for heavy metals in the soil showed that vanadium (V), manganese (Mn), and barium (Ba) had very severe contamination (VSC) in the humus soil. Nickel (Ni) and copper (Cu) are severely contaminated in the soil, whereas (Fe), Chromium (Cr), and Zinc (Zn) are moderately contaminated.  Titanium (Ti) has slightly contaminated the soil.