Evidence of chromium dust pollution on the leaves of food and medicinal plants from mining areas of Sekhukhuneland, South Africa

Abstract Leaves of food and medicinal plant species occurring in the vicinity of chromium (Cr) mines and ferrochrome smelters in Sekhukhuneland, South Africa, were investigated for evidence of Cr dust deposition. Leaf morphology was assessed to identify traits that could enhance dust adhesion. Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) analysis techniques were employed. EDS analysis confirmed Cr on leaf surfaces of 67% of species investigated and recorded Cr in up to 43% of analysed dust particles found on these species. Cr was detected in PM2.5 (0.1‒2.5 µm), PM10 (2.5‒10 µm) and PM > 10 µm. Assessment of leaf macromorphology indicated significantly higher amounts of EDS detected Cr (weight percentage, wt%) on the adaxial surface (p