地球科学と気候変動ジャーナル

抽象的な

Characterization of Surface and Trapped Dust Samples Collected around Human Settlements That are in the Vicinity of Old Mine Tailings in Mpumalanga Province, South Africa

Shadung J Moja, Maphuti G Kwata, Lerato M Sebesho, Khuthadzo G Masindi1 and Fanyana Mtunzi

Asbestos mining is banned in many countries because of the health effects that are linked to the inhalation of asbestos dust/fibres. Most of asbestos mine tailings in Mpumalanga Province are not rehabilitated and dust/fibres are easily eroded by weather and settle in sensitive areas like human settlements. Surface and trapped dust samples were collected around human settlements that are in the vicinity of five abandoned and ownerless asbestos mine tailings in October 2015. After collection, surface dust samples were sieved with a 100 μm pore size stainless steel sieve to remove large dust particles. Trapped dust material was collected outdoors around the window panes in houses, on surfaces of old furniture and on windscreens of old cars. Surface and trapped dust samples were treated in the laboratory in preparation of analyses by the Scanning Electron Microscope – Energy Dispersive Spectrometry (SEM - EDS), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) techniques. Both the serpentine (Mg₃SiO₅(OH)₄ and amphibole [Ca₂(Fe, Mg)₅Si₈O₂₂(OH)₂] asbestos mineral groups were detected from the samples. Other silicate minerals present include the quartz (SiO₂), talc [Mg₃Si₃O_{10(OH)3], feldspar [(KAlSi3O8)^- (NaAlSi3O8)^-(CaAl2Si2O8)] and smectite [(Na,Ca)0.33(Al, Mg)2 (Si4O10)(OH)2. nH2O]. Non silicates minerals which were detected are hematite (Fe2O3d), chlorite (ClO2^-), magnetite (Fe3O4), gibbsite [Al(OH)3], dolomite [Ca-Mg (CO3)2] and ilmenite (FeTiO3). Industrial and biological materials that include fly ash particles, organic and glass fibres were also detected. While the amounts detected are at trace levels, but the continued presence of asbestos minerals around residential areas is of concern.}