Application of Arc-GIS for zoning of occupational exposure levels to respirable crystalline silica in crushing factories

The silica crushing is a process based on crushing, screening and, granulation of various types of silica rocks. The inhalation of silica dust leads to silicosis by causing irreversible fibrosis in lung tissue. The crystalline silica is classified as a human carcinogenic (group I) by the IARC. Azandarian region is one of the largest silica production units in Iran with 40 silica crushing factories. This study was conducted to application of Arc-GIS for zoning of occupational exposure to respirable crystalline silica (RCS) in this region.

In this descriptive study, the personal exposure levels to RCS in 16 workers silica crushing factories were measured according to the NIOSH method 7602. Also, 16 air samples were collected and quantified simultaneously to evaluate the environmental concentrations in the studied factories.

The results showed that the personal exposure level mean (2.01±2.61mg.m-3) was more than OEL proposed by the Technical Committee of Occupational Health of Iran country (0.025mg.m-3). The results showed a statistically significant difference between the mean concentration of the personal exposure to RCS in the different job activities (P = 0.001).

The results showed that there was no significant relationship between the personal exposure levels and environmental concentrations of the RCS. These findings showed that GIS has a desirable ability for zoning of occupational exposure levels to RCS in workplaces. This study also emphasizes the use of other modeling methods to determine the amount of silica release in the different units of the silica crushing factories.