Journal of School of Public Health and

Background and Aim: Work-related Musculoskeletal Disorders (WMSDs) are the most prevalent occupational diseases and injuries. The aim of this investigation was WMSDs risk factors study in building construction industry by PATH (Posture, Activity, Tools and Handling) method.

Materials and Methods: This analytical-descriptive and cross-sectional study was conducted in four construction sites. A total of 3100 observations of 89 workers in 14 jobs were obtained. The percent of time determined for trunk, legs and hands postures, and manual material handling activities, used tools and handling in job tasks.

Results: Trunk, legs and hands postures, tools and objects weight differed significantly between stages (P<0.0001). Neutral trunk posture was observed frequently. Neutral legs and hands postures were observed greater than %50 and %80 of the time respectively in studied workers. Tools are used with different frequency in studied jobs. Loads with less than 5 Kg were handled repeatedly.

Conclusion: The result of this study can be used to reduce musculoskeletal disorders in construction workers. This study revealed construction workers spent more time with neutral postures. But ergonomic interventions should be accomplished in specified jobs.

Background and aim: In this study the cytotoxicity to human epithelial lung cells of single-walled carbon nanotubes, multi-walled carbon nanotubes and chrysotile was compared based on the following cytotoxicity indices: no observable adverse effect concentration (NOAEC), inhibitory concentration 50 (IC50), and Total Lethal Concentration (TLC).

Materials and Methods: Human epithelial lung cells were exposed to different concentrations (1 to 1500 µg/ml) of carbon nanotubes and chrysotile for 6 and 24 hours. Cytotoxicity was assessed using the MTT assay. NOAEC, IC50, and TLC idices were determined by probit analysis.

Results: The results showed statistically significant correlations (p<0.001) between cytoxicity and exposure concentration in the case of all the three compounds. The NOAEC and IC50 indices were lowest for the multi-walled carbon nanotubes, while the single-walled carbon nanotubes showed the lowest TLC index.

Conclusion: Cytotoxicity of multi-walled carbon nanotubes at low concentrations was higher than that of single-walled carbon nanotubes and chrysotile. This would mean that exposure to this compound occurs at low concentrations. Thus, cytotoxicity of multi-walled carbon nanotubes is a cause for concern. It can be concluded, then, that, like chrysotile fibers, crabon nanotubes are also considerably toxic to human epithelial lung cells.