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Exposure of asbestos dust comes from several sources that include mine dumps, unpaved road made of asbestos materials, blasting, crushing, grinding and milling activities, as well as spillages from trucks carrying the asbestos materials. The threat to human health is exacerbated by wind blowing over uncovered asbestos dust, making it airborne and inhaled by nearby local communities. The aim of this case study is to measure the dust-fall rates, characterize the dust and determine the metal levels in the resulting filtrate solutions within the Mpumalanga study area. The standard method for collection and analysis of dust-fall rates adopted by the American Standard Test Method (ASTM D 1739(ASTM D , 1970 and the South African National Dust Control Regulations (NDC R 827, 2013) was used. Filtrate solutions generated after filtering the collected falling dust were analyzed with Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) to determine the levels of some trace metals. Dust samples were characterized with a Scanning Electron Microscopy-Energy Dispersive Spectrometry (SEM-EDS) to determine the morphology such as shape, size, length and width of asbestos fibers. Dust-fall rates measured from January to June 2016 were all below the residential standard limit of 600 mg/m 2 /day at all five sampling sites. Site E was the highest with 478 mg/m 2 /day measured in May 2016, possibly due to its close proximity to the asbestos mine dump. All trace metals of interest (manganese (Mn), iron (Fe), nickel (Ni), cadmium (Cd) and lead (Pb)) exceeded the local and international standard limits. SEM-EDS results confirm the dominance of silicates minerals that include the serpentine (Mg3(OH)4(Si3O5), amphibole (NaCa2(Mg,Fe,Al)5(Al,Si)8O22(OH)2, quartz (SiO2), plagioclase (NaAlSi3O), kaolinite (Al2Si2O5(OH)4Mg,Fe ++5 Al(Si3Al)O10(OH)8, feldspar (KAISQ3O8) and mica (KAI2(Si3Al)10)(OH)2. The presence of poisonous metals and asbestos fibers could have negative health impacts to the exposed individuals.

Penge is an asbestos-contaminated area with a high incidence of asbestos-related diseases amongst its residents due to exposure to airborne asbestos fibres. The following paper presents an assessment of asbestos fibre exposure in the ambient air of the area. The objective of the study was to quantify the level of airborne asbestos fibre concentration in an endeavour to understand the health risk to which residents are exposed. The study was carried out based on air analyses data of the area acquired from the Council for Geoscience as well as health risk assessment techniques guided by the Risk Assessment Guidance for Superfund (EPA, 1989). It was found that the average asbestos fibre concentration in the ambient air of the study area was 0.047 f/mL which is lower than the 0.2 f/mL limit stipulated by the South African government. However, the asbestos fibre concentration in ambient air of the study area is much higher than the 0.0005 f/mL limit stipulated by the World Health Organization. The average cancer risk for all age groups in the study area was 2.08 × 10 −3 . When compared with the Environmental Protection Agency National Contingency Plan standard which accepts the risks within the range between 10 −4 (0.0001) and 10 −6 (0.000001), it was found that the results obtained in the study area generally exceed the standard. It is recommended that all of the sources of asbestos in the area be rehabilitated.

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