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.

Risk Assessment of Computer Users' Upper Musculoskeletal limbs Disorders in a Power Company by means of RULA Method and NMQ in 1390

Background and aims: Development and rapid increase of computer usage in all aspects of industry and society has been caused remarkable increase in musculoskeletal disorders of upper limbs. So, this study was conducted to determine the prevalence of upper musculoskeletal limbs disorders, to assess potential risk to them and their relations with demographic characteristics among computer users of a power company`s Computer Users

Materials and Methods: In this cross sectional and descriptive - analytic study, all computer users who worked in official units [60 people] of a power company that had entry criteria were chosen in 1390. In this study, Nordic questionnaire and RULA method were used. Data gathering was analyzed by applying SPSS13 software, statistical tests, Chi-Square and Independent Sample T- test

Results: The results of the questionnaire revealed that the most pain was related to back [80.00%], neck [73.30%], arms/ wrists [73.30%], and shoulder [46.70%] respectively, in past year. There was also significant relation between the outbreak of back musculoskeletal disorders with age variations, job experience, and users` length [p<0.05]. The results of RULA revealed that 73.3%, 6.7% and 20% of computer users were exposed to medium, high, and very high risk of exposure to work, respectively

Conclusion: Computer users were determined from the medium risk level to very high risk level. Thus, in accordance with determined priority level of corrective action, ergonomic intervention and changes commensurate with working condition should be carried out. In order to prevent disorders and obtaining more efficiency, ergonomic instructions related to working with computer were trained to staffs and recommendations were presented in this field