Purpose Pneumoconiosis is a kind of diffuse lung fibrosis disease caused by long-term inhalation of industrial dust and retention in the lungs. In recent years, the incidence of pneumoconiosis decline in Europe, America and other developed countries, but remains stubbornly high in China, and even shows a rising trend. Currently, China does not have a comprehensive pneumoconiosis risk index system for risk assessment. This project aims to review methods to construct the risk index system of occupational dust exposure. A comprehensive, evidence-based and practical risk index system will offer a solid foundation for calculating the risk index weightings, adjusting indicator system and practical application in the future. Method Pubmed search was conducted for all the literature in 2000 -2014 about the risk factors of pneumoconiosis. RCT trials, cohort studies and case-control studies were identified to explore the risk factors of pneumoconiosis. Animal experiments, clinical research, radiological research, genetic research, and simple descriptive studies were excluded. Referring to "The Law of Occupational Disease Prevention in People's Republic of China" and national occupational health risk assessment system in other countries and an occupational dust risk index system prototype was formulated. Result 19 highly relevant literatures were identified from the systematic review. We found that dust concentration, working duration, age and smoking habit are highly correlated to the risk of pneumoconiosis. Combined with occupational health risk assessment systems in other countries and "The Law of Occupational Disease Prevention in People's Republic of China", the primary occupational risk index system was built. The system totally included four level indicators, 11 secondary indicators and 48 tertiary level indicators, covering human factors, physical factors, environmental factors and the management factors. Conclusion The primary risk index system not only covers the detail of production process from the dust generation to the dust spread, but also includes personal risk exposure caused by individual differences, working environment and hazards caused by improper management. It is trusted to be a comprehensive risk index. However, the index system needs further statistical analysis, like setting the index weight and testing with the data collecting from actual work, to improve the rationality and practicality of the index system. / published_or_final_version / Public health / Master / Master of Public Health

Pneumoconiosis in rural Transkeian women termed "Transkei Silicosis" has been thought to be caused by silica inhaled while grinding maize by traditional methods (Palmer and Daynes, 1967). This study was undertaken to investigate the features and causes of hut lung. The range of clinical, radiologic, histologic, pulmonary physiologic and broncho-alveolar lavage features in patients meeting the following criteria was assessed: i) rural women practising traditional cooking methods ii) with a diffuse nodularity on chest x-ray iii) and lung biopsy evidence of pneumoconiosis iv) and without occupational exposure v) or evidence of active tuberculosis. Smoke and dust levels were measured in rural dwellings during cooking and maize grinding and ground maize and grinding rocks were analysed. 25 patients were studied. 17 were non-smokers, 5 were pipe smokers and 3 smoked 10 or less cigarettes per day. 7 had evidence of previous tuberculosis. The radiological findings ranged from a diffuse fine miliary pattern through coarse nodules with coalescence, to extensive fibrosis resembling PMF. The histologic features revealed simple "anthracosis" in 12, anthracosis with macules in 6 and mixed dust fibrosis in 7, of which 2 had silicotic nodules and 1 PMF. No such findings were observed in the control lung biopsy specimens obtained at post-mortem from city dwelling Xhosa females. Mild to moderate airflow limitation (defined as an FEV1/FVC ratio of < 65% and/or RV> 145% of predicted) was present in 73% while a reduced T'LCO (< 80% predicted) was found in 76% of the patients. Cell numbers and differential counts in BAL fluid were normal but> 80% of the macrophages were heavily laden with inorganic inclusions. The mean smoke level during indoor open fire cooking was 30mg/m³. Respirable dust and quartz concentrations ranging from 3,03 to 5, 82mg/m³ and 0,097 to 0,186mg/m³ respectively were found during hand grinding with sandstone (100% quartz), but were lower (ranging from 2,62 to 3,40mg/m³ and 0,024mg/m³ respectively) when non-quartz containing dolerite was used. Calculated cumulative equivalent time-weighted average respirable dust concentrations were shown to be similar to those found in an average South African gold mine while calculated equivalent respirable quartz concentrations were well below those found in the worst exposed gold miners and well within the recommended threshold limit values of the National Institute for Occupational Safety and Health (NIOSH) and the World Health Organisation (WHO). Respirable quartz exposure alone was not sufficient to explain the changes found. Respirable non-quartz containing nuisance dust and intense smoke exposure were shown to be significant. It was concluded that: i) hut lung can be defined as a domestic pneumoconiosis that occurs in rural women who practise primitive cooking methods ii) hut lung typically occurs in rural maize grinding Transkeian women but can occur in other rural women iii) there is a wide clinical, spectrum radiological and histologic iv) the pulmonary physiological changes are predominantly those of airflow limitation with some CO transfer factor reduction v) cigarette and pipe smoking do not contribute to the aetiology or pulmonary physiological abnormalities vi) the bronchoalveolar lavage features may help differentiate this condition from miliary tuberculosis vi) the aetiology of hut lung is multifactorial with exposure to respirable quartz and non-quartz containing dust together with smoke particles from biomass fuelled fires all playing a significant role while previous tuberculosis may be a contributing factor.

published_or_final_version / Medicine / Master / Doctor of Medicine

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No description available.

Thesis (MPH. (Occupational and Environmental Health))-- University of Limpopo, 2012 / Background: The objective of this study was to quantify personal time-weighted average respirable dust and silica exposure of workers at foundries in Gauteng and to rank the occupations in foundries according to the risk of exposure to silica quartz. Methods: A task-based risk assessment of 56 personal samples from two foundries was conducted. Personal exposure data was collected from workers’ breathing zones for the full working shift. All analyses of samples for silica dust were carried out in the CSIR Centre for Mining Innovation’s Laboratory, which has SANAS accreditation (ISO 17025) for both x-ray powder diffraction and particle size analysis methods. Results: The personal time-weighted average mean and median respirable silica dust concentration was 0.184 mg/m³ and 0.167 mg/m³ respectively. The maximum exposure concentration was 0.835 mg/m³ and minimum exposure was 0.010 mg/m³. The occupations within the foundries with the highest exposures were moulders, sand mixers, furnace operators and the lowest exposed occupations were grinders, closers, and casting operators. The majority of foundry workers (62%) in both foundries are exposed to respirable silica dust at above the South African occupational exposure level (OEL). Conclusion and recommendations: Foundry workers are over-exposed to respirable silica dust and are potentially at high risk of contracting silicosis and other occupational diseases associated with respirable silica dust. It is recommended that a dust control programme be implemented and a baseline study be conducted.

A case control study was performed in 6 cotton mills in KwaZulu-Natal, South Africa. The study used questionnaire and pulmonary function testing results to categorise respiratory symptoms in 52 exposed symptomatic, 30 exposed asymptomatic and 46 unexposed control subjects. These categorisation results were used to explore the relationship between serum IgG subclasses and cotton-specific IgG to byssinosis. No definitive relationships between the serum IgG subclasses and clinical and functional symptoms of byssinosis were found . Whereas, exposed symptomatic (22.72 mg All) subjects had significantly higher (P = 0.01) mean specific IgG concentrations than exposed asymptomatic (15.02 mg All) or unexposed control (13.08 mg All) subjects. A pathoaetiological or marker-aetiological role is indicated for specific IgG in the development of byssinosis. The findings of this research challenged the status quo in terms of the accepted aetiological pathways of byssinosis. In turn the acceptance of a different aetiological pathway provided a possible answer to the varying presentation of the disease and by implication contested the current definition of byssinosis. / Thesis (M.Med.Sc.)-University of Natal, Durban, 2002.

Indoor air quality is described as the chemical, physical and biological characteristics of air in a residential or occupational indoor environment. In residential settings, there are many contributions to indoor pollution levels namely; human activities, biological sources and outdoor air. There has been increased focus on house dust due to its potential to contain biological and chemical pollutants in indoor environments. These have the potential to cause harm to human health. The purpose of this study was to conduct toxicological analysis of house dust collected from inside selected Durban residential buildings. The objectives of this study were to isolate, identify and quantify mould occurrence in house dust samples; to measure the occurrence of heavy metals (arsenic, lead and mercury) in house dust; and to analyse the cytotoxicity of house dust on human lung bronchus carcinoma epithelial line (A549) and human lung bronchus virus transformed epithelial cell line (BBM). One hundred and five house dust samples were obtained from households that participated in the South Durban Health Study. In each home, a sample of settled dust was collected, using standardized protocols, then sieved and individually packed into polystyrene bags. The samples were taken from three surface areas namely; living room couches, bed mattresses, and carpets. Well documented methods were used for the isolation, identification and quantification of mould. The samples for heavy metals analysis were sent to Umgeni Water (chemistry laboratory, Pietermaritzburg) where standardised methods were used. Human cell lines were treated with five different dilutions of each house dust extract. Cell viability was assessed using the MTT assay. Toxic effects of house dust extract were analyzed, following house dust extract treatment and cells were stained with double dye (annexin-V- and propidium iodide) and analysed with flow cytometry, and fluorescent microscope. Cytokines were analysed by Microbionix (Neuried, German) using a Luminex®100 plate reader for multiplex human cytokines analysis. There were (n=128) mould types isolated and (n=105) were identified, of which (n=10) were predominately isolated moulds. This was further confirmed by Allerton Provincial Laboratory in Pietermaritzburg. Among the isolated genera in all three surface areas, Rhizopus spp and Penicillium spp were widely distributed throughout surface areas in greater proportion. The overall highest mean which was reported in this study and expressed in colony forming unit per gram (CFU/g) for Penicillium spp ranged (3400 - 62316 CFU/g) obtained from living room couches, followed by Rhizopus spp (5200 - 15990 CFU/g). The mould results were compared with the South African Occupational Health and Safety Act (OHSA) 85 of 1993 as amended suggested guidelines of 1,000, 000 CFU/g. The findings of this study suggest the moulds in the homes studied were below the suggested guideline. However, this does not imply that the indoor conditions are unsafe or hazardous. Instead, the findings act as an indicator of moulds presence indoors. The type of airborne mould, its concentration and extent of exposure and the health status of the occupants of a building will determine the health effects on an individual. Heavy metals were detected in the dust in the following ascending order: arsenic (As) ranged from 1.3 ug/g -18.4 ug/g (mean, 4.26 ug/g), lead (Pb) ranged from 28.0 - 872 ug/g (mean 171.66 ug/g), and mercury (Hg) ranged from 0.6 -19.0 ug/g (mean, 2.22 ug/g). The mean concentration of lead in the dust was within the range of Canadian National Classification guidelines on residential contamination (500 ug/g). There was numerous numbers of samples in this study that exceeded these guidelines. The mean concentration of arsenic was within residential soil guidelines (20 ug/g). Mercury was within limits when compared with Global Hg project guidelines of soil/residential (6.6 ug/g), thought some of samples were notably above this mean. The ability of house dust extract to lower the cell viability which was slightly above 80% (prior treatment) to less than 50% (post treatment) in both cells was observed in this study. The findings in this study showed that dust extract are toxic to human cell lines, and cells undergone a degree of apoptosis and necrosis 62% (A549) and 99% (BBM). The cytokines serve an important role in the non-specific defence external against insults. It was observed that A549 cells up-regulated the release of IL-6 and IL-8 pro-inflammatory cytokines and under-regulated the release of other cytokines analysed (IL-4, IL-13, and TNF-a). BBM cells released IL-4, IL-8 and IL-13 within limit of detection. The presence of moulds in these sampled indoor household dusts, which is comparable with findings elsewhere indoors, show that moulds act as an indicator for building conditions such as dampness, which supports mould growth. Individuals, whether they are sensitized or not, may develop allergic reactions towards spores, thus the elevated numbers of spores quantified in this study are of concern. Some of the heavy metals reported in this study were higher or marginally higher than international norms and guidelines. The findings in this study strongly suggest that house dust extract is toxic to human lung cell lines. It must be noted, however, that this study may not reflect all that happens when a human lung is exposed to house dust. The findings of this study could contribute to the development of South African indoor air guidelines. In conclusion further study needed to be undertaken with respect to air pollution disease such as allergic; the reason being this study shown the reduced expression of cytokines that are involved in allergic inflammation. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2009.