ABSTRACT
Growth of the plastics industry in recent decades has been dramatic. Poly Vinyl Chloride is one of the most widely used plastics in the world that granules in the thermal process decompose to Vinyl Chloride Monomer and is released in work air environment. This study aimed to evaluate occupational exposure and estimate workers' exposure with vinyl chloride monomer risk. A cross-sectional study of 100 workers at two Plastic factories in Tehran [A, B] was performed. Personal monitoring of workers to Vinyl Chloride Monomer was conducted by Optimized Method No.1007 from NIOSH. Atmospheric conditions, such as temperature, pressure, air velocity, and relative humidity were measured simultaneously along with personal monitoring. Quantitative risk assessment of workers was computed in the form of Standard Mortality Rate and incident rate cancer. Statistical analysis of data was conducted by SPSS version 19. Climatic parameters in the plant A and B for a relative humidity were 43.77 +/- 16.71 and 37.16 +/- 14.45% and temperature 20.95 +/- 3.34 and 21.05 +/- 2.20 degree C, air pressure 87.48 +/- 0.54 and 87.41 +/- 0.64 kPa and air velocity 0.13 +/- 0.08 and 0.10 +/- 0.06 meters per second were measured respectively. Occupational exposure to Vinyl Chloride Monomer plants A and B were 1.01 +/- 0.51 and 0.72 +/- 0.30 as ppm respectively. Quantitative risk of exposed workers based on Standard Mortality Rate was estimated 1.06 +/- 0.03 times of the population without exposure. Incident rate cancer based on accounting measures of integrated risk Information System was calculated per 1000 person exposure population. The correlation of Standard Mortality Rate and the risk of cancer incidence was statistically significant [R[2] :0.88]. Thirty one percent of workers had higher exposure to Vinyl Chloride Monomer than the occupational exposure limits [1 ppm]. In the present workers' exposure in this study is lower than international workforces reported in decades ago, but higher than studies recently published. The results clearly describes occupational hazard of workers in the current Iranian recession situation. The application of control system in the form of engineering control measure, especially in the coming years with projected economic growth, is justified for securing workers health and well-being.
ABSTRACT
Aluminum and in particular its compounds make up a large proportion of the pollutants coming from the aluminum foundry. In several studies conducted on the harmful effects of aluminum in recent decades, it has been identified as a neurotoxic metal. Chronic occupational exposure through inhalation of dust is a common problem in aluminum foundries. Investigation of the exposure of various occupational groups in two aluminum foundry plants to aluminum aerosols. To study the occupational exposure of foundry workers to respirable aerosols of aluminum, personal sampling was conducted from the breathing zone of 63 workers at two foundries in the south of Tehran city following NIOSH method No. 0600. Then samples were treated using NIOSH Institute optimized method No. 7013 and analyzed by high sensitivity graphite atomic absorption.Collected data were analyzed with SPSS V.16 statistical software using an independent sample t-test and ANOVA. The average of aluminum respirable aerosols in A and B factories were 3.21 +/- 2.33 and 3.31 +/- 2.15 mg/m[3] respectively. The one-way ANOVA indicated that occupational exposure among various occupational groups [Similar Exposure Group] in Foundry A had no significant difference [p=0.089], but differences between the exposure of melting and assembling groups in Foundry B are significant [p=0.044]. In general, in exposure frequency to aerosols in aluminum foundries, a significant difference was observed between melting and assembling groups [p=0.005] as well among abrading and assembling groups [p=0.02]. Most of the exposures to aluminum in foundry workers exceeded the current limits given by ACGIH Institute and the Iranian occupational exposure limits. According to the occupational exposure of both foundries and the absence of differences among variables involved in the exposure, the high exposure of melting and abrading groups compared to assembling groups can be attributed to the nature of these units in the production of aluminum aerosols.