Determination of platinum group metals in dust, water, soil and sediments in the vicinity of a cement manufacturing plant

Abstract

Global economic growth has led to an increase in cement production to meet the demand of infrastructural development over the past decades. This has resulted in cement factories being the major sources of dust pollution. Dust emanating from the cements plants deposits on buildings, roadways, on road pavements and plants. The purpose of this study was to determine the concentration of platinum group metals (PGMs) emitted with cement dust on a dust suppressed roadway next to a cement factory in Waterberg, South Africa. The concentrations of PGMs were determined using inductively coupled optical emission spectrometry. This region is well known for large reserves and mining of PGMs such as Pt, Rh, Ru and Pd. The highest concentration in the dust samples collected along the roadway was that of Pt followed by Ru, Rh and Pd. The concentrations of Pt, Ru, Rh and Pd in soil samples decreased with the increase of depth. Water concentration of PGMs decreased at each sampling point in the following order; Pt > Ru > Rh > Pd. Sediments samples were also sampled along the Crocodile River for characterisation of physico-chemical parameters. It was of great importance to also analyse PGMs in soils, water and sediments since, dust settles on them. Elevated concentrations of Pt were observed in all samples and the highest concentrations were partitioned to the small particle size fraction of 32 µm. The pH and electric conductivity (EC) of the sediments were measured and the pH values increased while EC values decreased moving along the river. The most common minerals identified in the dust samples were quartz and calcites. Vehicular emissions were also found to be the major contributor to suspended particulate matter and atmospheric deposition of dust dominantly result from emission from the cement plant. The cement plant was the major polluter through atmospheric deposition of dust particles. The result also revealed that the pH of the Crocodile River was slightly alkaline which was influenced by the effluent from the cement plant.