Risk Assessment of Exposure to Silica Dust in Building Demolition Sites

BACKGROUND: Building demolition can lead to emission of dust into the environment. Exposure to silica dust may be considered as an important hazard in these sites. The objectives of this research were to determine the amount of workers' exposure to crystalline silica dust and assess the relative risk of silicosis and the excess lifetime risk of mortality from lung cancer in demolition workers. METHODS: Four sites in the Tehran megacity region were selected. Silica dust was collected using the National Institute for Occupational Safety and Health method 7601 and determined spectrophotometrically. The Mannetje et al and Rice et al models were chosen to examine the rate of silicosis-related mortality and the excess lifetime risk of mortality from lung cancer, respectively. RESULTS: The amount of demolition workers' exposure was in the range of 0.085-0.185 mg/m³. The range of relative risk of silicosis related mortality was increased from 1 in the workers with the lowest exposure level to 22.64/1,000 in the employees with high exposure level. The range of the excess lifetime risk of mortality from lung cancer was in the range of 32-60/1,000 exposed workers. CONCLUSION: Geometric and arithmetic mean of exposure was higher than threshold limit value for silica dust in all demolition sites. The risk of silicosis mortality for many demolition workers was higher than 1/1,000 (unacceptable level of risk). Estimating the lifetime lung cancer mortality showed a higher risk of mortality from lung cancer in building demolition workers.

Dust exposure and respiratory health effects in cement production

Dust can be produced by almost all production processes in Portland cement factory. Dust exposure potentially can affect respiratory function. But evidence for respiratory effect of cement dust exposure has not been conclusive. In this study we assessed effect of cement dust exposure on respiratory function in a cement production factory. A respiratory symptoms questionnaire was completed and pulmonary function tests were carried out on 94 exposed and 54 non exposed workers at a cement factory in the east of Iran. Additionally, respirable dust level was determined by the gravimetric method. X-ray fluorescence [XRF] technique was performed to determine the silica phases and the SiO[2] contents of the bulk samples. The arithmetic means [AM] of personal respirable dust were 30.18 mg/m[3] in the crushing, 27 mg/m[3] in the packing, 5.4 mg/m[3] in the cement mill, 5.9 mg/m[3] in the kiln and 5.48 mg/m[3] in the maintenance that were higher than threshold limit value [TLV] of the American Conference of Governmental Industrial Hygienists [ACGIH] which is 5 mg/m[3]. This value in the unexposed group was 0.93 mg/m[3]. In this study cough, sputum, wheezing and dyspnea were more prevalent among exposed subjects. Exposed workers compared to the unexposed group showed significant reduction in Forced Expiratory Volume in one second [FEV[1]], Forced Vital Capacity [FVC], and Forced Expiratory Flow between 25% and 75% of the FVC [FEF[25-75%]] [P<0.05]. It can be concluded that in our study there was close and direct association between cement dust exposure and functional impairment among the cement factory workers

effect of cement dust on the lung function in a cement factory, Iran

The present study aimed at assessing cement dust exposure and its relationship to lung function at a Portland cement factory in Ilam, Iran. Lung function tests were carried out on 112 workers at the cement factory in 2008-09. Simultaneously 85 non exposed workers were used as control. Lung function tests were performed for all subjects. Additionally, total dust level was determined by the gravimetric method. Moreover, X-ray diffraction [XRD] technique was performed to determine the SiO2 contents of the bulk samples. The arithmetic means [AM] of personal total dust were higher in the crusher [27.49 mg/m3], packing [16.90 mg/m3], kiln [15.60 mg/m3], cement mill [13.07 mg/m3], raw mill [10.31 mg /m3] than in the maintenance [3.14 mg /m3], and administration [1.55 mg/m3]. The geometrical mean [GM] concentration was 12.12 mg/m3, which were considerably higher than occupational exposure limit [OEL] of the American Conference of Governmental Industrial Hygienists [ACGIH], which is 10 mg/m3. Based on the results, the probability of the long-term mean exposure exceeding to the OEL of 10 mg/m3 for total dust were higher in the kiln [100%], packing [100%], cement mill [90%], crusher [73%], raw mill [60%] than in the maintenance [0%], and administration [2.3%]. Ventiliatory function evaluation, as measured by the function parameters, showed that 35.7% of the exposed workers had abnormality in lung function compared with 5.7% of those unexposed. Statistical analysis of the data indicated that exposed workers compared to the unexposed groups showed significant reductions in Forced Expiratory Volume in one second percent [FEV1], Forced Vital Capacity [FVC], and FEV1/FVC [p< 0.05]

Ergonomics for special populations

The need for Rehabilitation ergonomics for working with special population is potentially greater than with non disabled population. Their quality of life can be influenced to a great extent. In accordance, databases and information should be developed and used for designing environments for special population. Design should consider injury prevention, productivity enhancement, ease of use, and acceptability to the particular population that will use the product, be it medical or a rehabilitation equipment, a consumer product, or tools in a work setting. An approach to applying rehabilitation ergonomics principles for special populations is introduced to help match task requirements with the functional capabilities of special populations. This approach also challenges the definitions of who may be considered disabled versus enabled by promoting the use of design concepts to alter task requirements. It is hoped that this concept and methodology will be used to benefit the lives of the individuals within special populations, and all of rehabilitation and social problem management