| dc.description.abstract | Tuberculosis is a disease that has a detrimental effect on the economic growth of
South Africa. The country’s TB mortality rate is amongst the highest in the world,
and the worst affected industry is mining. Effective environmental controls of
tuberculosis in mining areas remain a challenge, mainly because there is a lack of
quantitative data to guide the implementation of these controls. No occupational
exposure limits exist for bio–aerosols, particularly Mycobacterium tuberculosis. This
makes it difficult to distinguish between high– and low risk areas. It is believed that a
single inhaled M. tuberculosis particle can cause the tuberculosis disease, and as
this disease can deteriorate all major systems of the body, great care should be
taken in the classification of an area.
Aim: This study aimed to quantify the environmental presence of the M. tuberculosis
bacilli in various occupational settings of a platinum mine. Method: The monitored
areas are all structures above ground, and include high TB risk areas, such as the
hospital TB Ward, and low TB risk areas, such as an office area. Personal
monitoring of the staff in high TB risk areas has also been conducted. Monitoring
was done via the PTFE filter sampling method and the SKC Bio–Sampler impinger
method. The results of these two methods were compared to determine which
method is more effective.
The environmental variables, such as carbon dioxide and -monoxide levels,
temperature (both ambient and wet– bulb), and relative humidity, were also monitored
in order to identify any possible correlations between these variables and the levels
of ambient TB particles. The effectiveness of the Ultraviolet Germicidal Irradiation
(UVGI) system, which is in place in some of the monitored areas, was also indirectly
assessed, i.e. to see if there are any M. tuberculosis particles present in an area that
makes use of an UVGI system. The PCR analytical method was used to quantify the
number of M. tuberculosis bacilli sampled, and the results were statistically analysed.
Results: M. tuberculosis was found to be present in the office area, the laundry
room, the hospital’s waiting area, the training facility, the dining room, and the mobile
clinic. No M. tuberculosis particles were found in the hospital’s TB Ward and the
change houses of the mine. The results showed that the PTFE filter method had a
greater efficiency than the SKC Bio– Sampler in monitoring environmental M.
tuberculosis particles, as the PTFE filter method yielded positive samples where the
SKC Bio–Sampler did not. There is a practical significant difference between the
two methods. No viable correlations between the environmental variables and M. tuberculosis
prevalence were established due to the low number of samples taken.
Conclusion: It seems that the effectiveness of a UVGI system is dependent on the
number of people crowded into that specific area and the ventilation thereof. A UVGI
system is only a precautionary measure and not a solution.
There are too many factors that still need better understanding before the risk of
contracting environmental TB in high risk areas of a mine can be determined. The
high risk areas seem to be occupational settings that have poor ventilation, but
accommodate a large number of people. The highest risk of TB infection remains
close contact with infected individuals, as the results of the employee monitoring
testified. | en_US |
