Ammonium Nitrate-Fuel Oil (ANFO) is the explosive generally used in the mining industry to blast ore from the rock face. The use and detonation of ANFO explosives in an underground mine is an intrinsically hazardous process. The by-products formed during blasting have been well studied over the years and modern mining techniques and methods have evolved to mitigate the inherent blasting and gas emission risks. However, there is insufficient research and quantitative data on mine workers’ respiratory exposure to blasting gasses under realistic underground conditions. Aim: The objective of this study was to determine whether blasting gasses such as nitric oxide (NO), nitrogen dioxide (NO2) and ammonia (NH3) pose an inhalation health risk to underground mine workers cleaning at the blasting panels approximately three hours after the detonation of ANFO explosives. Scraper Winch Operators’ (SWOs) respiratory exposure to selected blasting gasses was simultaneously sampled by means of active and passive sampling methodologies. Method: Personal exposures to NO, NO2 and NH3 were measured and analysed in accordance with NIOSH methods 6014 and 6015. Along with the active air samplers, respiratory exposure to NO2 and NH3 were measured by means of radial symmetry diffusive samplers (Aquaria® RING). Measurements were taken over an 8-hour period, where this was not applicable; results were time weighed to an average 8-hour exposure concentration in order to compare the Scraper Winch Operators’ (SWOs) respiratory exposure to the Occupational Exposure Limits (OELs) contained in the Regulations of the Mine Health and Safety Act (No. 29 of 1996). Results: The active air sampling results indicated that the SWOs’ respiratory exposure to NO, NO2 and NH3 complied with their respective OELs contained in the Regulations of the Mine Health and Safety Act (No. 29 of 1996). However, one of the SWOs had an exposure which exceeded the action level (50% of OEL) at which level the implementation of control measures are recommended to reduce the SWO’s exposure. Based on the results of the Wilcoxon matched pairs test, statistical significant differences were observed between the exposure results of the two sampling methodologies for NO2 (p = 0.00078) and NH3 (p = 0.044), with the passive diffusive sampling technique under sampling when compared to the active sampling method. This was also confirmed by a Spearman rank order correlation which indicated a poor relationship between the two sampling methods for NO2 (r = -0.323) and NH3 (r = 0.090). Environmental conditions (i.e. temperature and humidity), as presented in an underground mine, may have been a major factor for the variation between the two sampling methods, mostly affecting the passive samplers. Conclusion: It was established that engineering and administrative control measures implemented at the underground mine were effective to control SWOs’ respiratory exposure to NO, NO2 and NH3 below their respective OELs. An acute health risk pertaining the inhalation of blasting gasses was, therefore, not presented to mine workers cleaning at the blasting panels approximately three hours after the detonation of ANFO explosives. However, long-term exposure to blasting gasses at low concentrations may present SWOs with a health risk if such exposures are not adequately controlled or mitigated. The dilution and production of blasting gasses also varied from one blasting level to another. Geological formation, explosive charge-up and loading practices, the amount of water vapour inside the stopes and ventilation parameters are among the factors that may have affected the amount of blasting gasses produced underground. In addition, a drop in the carbon monoxide levels as indicated by the mine’s central gas monitoring system would not necessarily mean a lowering in other blasting gas concentrations (i.e. elevated ammonia gas concentrations as identified in the present study). The personal exposure levels between the active and passive sampling measurements also differed considerably. This may be ascribed to the impact underground mining conditions and processes had on the sampling media as well the complexities involved when sampling blasting gasses in general. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Ammonium Nitrate-Fuel Oil (ANFO) is the explosive generally used in the mining industry to blast ore from the rock face. The use and detonation of ANFO explosives in an underground mine is an intrinsically hazardous process. The by-products formed during blasting have been well studied over the years and modern mining techniques and methods have evolved to mitigate the inherent blasting and gas emission risks. However, there is insufficient research and quantitative data on mine workers’ respiratory exposure to blasting gasses under realistic underground conditions. Aim: The objective of this study was to determine whether blasting gasses such as nitric oxide (NO), nitrogen dioxide (NO2) and ammonia (NH3) pose an inhalation health risk to underground mine workers cleaning at the blasting panels approximately three hours after the detonation of ANFO explosives. Scraper Winch Operators’ (SWOs) respiratory exposure to selected blasting gasses was simultaneously sampled by means of active and passive sampling methodologies. Method: Personal exposures to NO, NO2 and NH3 were measured and analysed in accordance with NIOSH methods 6014 and 6015. Along with the active air samplers, respiratory exposure to NO2 and NH3 were measured by means of radial symmetry diffusive samplers (Aquaria® RING). Measurements were taken over an 8-hour period, where this was not applicable; results were time weighed to an average 8-hour exposure concentration in order to compare the Scraper Winch Operators’ (SWOs) respiratory exposure to the Occupational Exposure Limits (OELs) contained in the Regulations of the Mine Health and Safety Act (No. 29 of 1996). Results: The active air sampling results indicated that the SWOs’ respiratory exposure to NO, NO2 and NH3 complied with their respective OELs contained in the Regulations of the Mine Health and Safety Act (No. 29 of 1996). However, one of the SWOs had an exposure which exceeded the action level (50% of OEL) at which level the implementation of control measures are recommended to reduce the SWO’s exposure. Based on the results of the Wilcoxon matched pairs test, statistical significant differences were observed between the exposure results of the two sampling methodologies for NO2 (p = 0.00078) and NH3 (p = 0.044), with the passive diffusive sampling technique under sampling when compared to the active sampling method. This was also confirmed by a Spearman rank order correlation which indicated a poor relationship between the two sampling methods for NO2 (r = -0.323) and NH3 (r = 0.090). Environmental conditions (i.e. temperature and humidity), as presented in an underground mine, may have been a major factor for the variation between the two sampling methods, mostly affecting the passive samplers. Conclusion: It was established that engineering and administrative control measures implemented at the underground mine were effective to control SWOs’ respiratory exposure to NO, NO2 and NH3 below their respective OELs. An acute health risk pertaining the inhalation of blasting gasses was, therefore, not presented to mine workers cleaning at the blasting panels approximately three hours after the detonation of ANFO explosives. However, long-term exposure to blasting gasses at low concentrations may present SWOs with a health risk if such exposures are not adequately controlled or mitigated. The dilution and production of blasting gasses also varied from one blasting level to another. Geological formation, explosive charge-up and loading practices, the amount of water vapour inside the stopes and ventilation parameters are among the factors that may have affected the amount of blasting gasses produced underground. In addition, a drop in the carbon monoxide levels as indicated by the mine’s central gas monitoring system would not necessarily mean a lowering in other blasting gas concentrations (i.e. elevated ammonia gas concentrations as identified in the present study). The personal exposure levels between the active and passive sampling measurements also differed considerably. This may be ascribed to the impact underground mining conditions and processes had on the sampling media as well the complexities involved when sampling blasting gasses in general. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Nickel is one of the most commonly known sensitisers and has been classified by the International Agency for Research on Cancer (IARC) as a possible carcinogen to humans (group 2B). Workers at a South African base metal refinery packaging area are potentially exposed to many hazardous chemicals that include nickel. Aims and Objectives: The aim and objectives of this study were to assess dermal and respiratory exposure of workers exposed to nickel in a packaging section at a South African base metal refinery and to assess the change in skin barrier function during a work shift by measuring percentage change in trans epidermal water loss (TEWL), skin hydration and skin surface pH. Skin health was established with a skin questionnaire. Surfaces that workers may come into contact with were also assessed. Method: Respiratory and dermal exposure assessment was done concurrently. Respiratory exposure was assessed and analysed by using the National Institute for Occupational Safety and Health (NIOSH) method 7300. The Institute of Occupational Medicine (IOM) inhalable aerosol sampler was used for personal air sampling. The TEWL index, skin hydration and skin surface pH of the index finger, palm, forearm and forehead were measured before and at the end of the shift with a Derma Measurement Unit, EDS 12 and Skin-pH-Meter® pH 905. These measurements were reported as percentage change in skin barrier function during the shift. Dermal exposure samples were collected with Ghostwipes™ from the index finger and palm of the dominant hand before, during and at the end of the shift, while samples from the forearm and forehead were only collected before and after the shift. Surface sampling was collected and all wipes were analysed for nickel according the NIOSH method 9102, using inductively coupled plasma-atomic emission spectrometry. Results: Respiratory exposure for the whole group of workers in a packaging section was well below the eight hour Time Weighted Average (TWA) respiratory Occupational Exposure Limit (OEL) of 0.5 mg m-3 for nickel. Dermal nickel loading was detected for all the job categories on all the anatomical areas even before the shift had commenced. During the shift more nickel was detected on the index finger and palm of the hand. Levels on the forearm and forehead were much lower in comparison with the index finger and the palm of the hand. Workplace surfaces, which workers may come into contact with on a daily basis, were also contaminated with nickel. Forklift drivers showed high exposure on the index finger and palm of their hands, and this can be attributed to them not wearing any gloves for hand protection. An increase in percentage change for TEWL was seen for most of the job categories on all anatomical areas measured during the shift. Percentage change in skin surface pH and skin hydration varied among job categories. Conclusion: The research addressed the problem statement, with the stated objectives. It was hypothesised that workers at a packaging section of a base metal refinery are exposed to quantifiable levels of nickel through the dermal exposure route. The hypothesis was accepted and control measures together with future studies were recommended. The results confirmed that all workers at a base metal refinery are exposed to quantifiable levels of nickel through the dermal exposure route. Dermal exposure was evident on all anatomical areas for all job categories before the shift had commenced. Personal protective equipment was provided to all employees, but forklift drivers did not wear gloves when operating the forklift. Respirable exposure to nickel was below the OEL. Changes in TEWL and to a lesser extent skin hydration, suggest a deterioration in skin barrier function during the shift. Forklift drivers as well as plate washers may be the highest risk job categories in developing allergic contact dermatitis. Several measures to lower respiratory and dermal exposure to nickel are also recommended. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Nickel is one of the most commonly known sensitisers and has been classified by the International Agency for Research on Cancer (IARC) as a possible carcinogen to humans (group 2B). Workers at a South African base metal refinery packaging area are potentially exposed to many hazardous chemicals that include nickel. Aims and Objectives: The aim and objectives of this study were to assess dermal and respiratory exposure of workers exposed to nickel in a packaging section at a South African base metal refinery and to assess the change in skin barrier function during a work shift by measuring percentage change in trans epidermal water loss (TEWL), skin hydration and skin surface pH. Skin health was established with a skin questionnaire. Surfaces that workers may come into contact with were also assessed. Method: Respiratory and dermal exposure assessment was done concurrently. Respiratory exposure was assessed and analysed by using the National Institute for Occupational Safety and Health (NIOSH) method 7300. The Institute of Occupational Medicine (IOM) inhalable aerosol sampler was used for personal air sampling. The TEWL index, skin hydration and skin surface pH of the index finger, palm, forearm and forehead were measured before and at the end of the shift with a Derma Measurement Unit, EDS 12 and Skin-pH-Meter® pH 905. These measurements were reported as percentage change in skin barrier function during the shift. Dermal exposure samples were collected with Ghostwipes™ from the index finger and palm of the dominant hand before, during and at the end of the shift, while samples from the forearm and forehead were only collected before and after the shift. Surface sampling was collected and all wipes were analysed for nickel according the NIOSH method 9102, using inductively coupled plasma-atomic emission spectrometry. Results: Respiratory exposure for the whole group of workers in a packaging section was well below the eight hour Time Weighted Average (TWA) respiratory Occupational Exposure Limit (OEL) of 0.5 mg m-3 for nickel. Dermal nickel loading was detected for all the job categories on all the anatomical areas even before the shift had commenced. During the shift more nickel was detected on the index finger and palm of the hand. Levels on the forearm and forehead were much lower in comparison with the index finger and the palm of the hand. Workplace surfaces, which workers may come into contact with on a daily basis, were also contaminated with nickel. Forklift drivers showed high exposure on the index finger and palm of their hands, and this can be attributed to them not wearing any gloves for hand protection. An increase in percentage change for TEWL was seen for most of the job categories on all anatomical areas measured during the shift. Percentage change in skin surface pH and skin hydration varied among job categories. Conclusion: The research addressed the problem statement, with the stated objectives. It was hypothesised that workers at a packaging section of a base metal refinery are exposed to quantifiable levels of nickel through the dermal exposure route. The hypothesis was accepted and control measures together with future studies were recommended. The results confirmed that all workers at a base metal refinery are exposed to quantifiable levels of nickel through the dermal exposure route. Dermal exposure was evident on all anatomical areas for all job categories before the shift had commenced. Personal protective equipment was provided to all employees, but forklift drivers did not wear gloves when operating the forklift. Respirable exposure to nickel was below the OEL. Changes in TEWL and to a lesser extent skin hydration, suggest a deterioration in skin barrier function during the shift. Forklift drivers as well as plate washers may be the highest risk job categories in developing allergic contact dermatitis. Several measures to lower respiratory and dermal exposure to nickel are also recommended. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014