Exploring a new method for the biological monitoring of plastic workers exposed to the vinyl chloride monomer.

Vinyl chloride monomer (VCM) is widely used in the production of polyvinyl chloride (PVC) plastics. VCM is recognized as a confirmed human and animal carcinogenic compound. Recent studies have reported poor health of plastic workers, even having exposure at concentrations below the permissible limit to VCM. There has not been any study regarding exposed workers to VCM in Iran. Similarly, no information exists as to the biological monitoring of such workers. The main purpose of this study was to conduct a thorough occupational and biological monitoring of Iranian plastic workers exposed to VCM.A total of 100 workers from two plastic manufacturing plants (A and B) in Tehran along with 25 unexposed workers as controls were studied. The personal monitoring of all nonsmoking workers exposed to VCM at two plastic manufacturing plants (A and B) was performed in the morning shift (8 a.m. to 4 p.m.) according to the National Institute For Occupational Safety And Health method no. 1007.Biological monitoring of workers was carried out through collection of exhaled breath of all exposed and control workers in Tedlar bags and with a subsequent analysis using gas chromatography-flame ionization detector.Not only the mean occupational exposure of workers to VCM at plant A was higher than the respective threshold limit value but also the statistical significance was higher than workers at plant B. Similarly, VCM concentration in exhaled breath of workers at plant A was also statistically significantly higher than at plant B. Correlation of occupational exposure of all workers to vinyl chloride with its concentration in exhaled breath was statistically significant.This is the first study on biological monitoring for exposed plastic workers to VCM using exhaled breath. On the basis of the results in this study, a novel method of biological monitoring of plastic workers was proposed.

Development and Validation of a Questionnaire for Preliminary Assessment of Heat Stress at Workplace.

BACKGROUND: Current heat stress indices are not completely suitable for heat strain screening in developing countries due to their inherent and applied limitations. The aim of this study was development of a questionnaire method entitled "Heat Strain Score Index" (HSSI) in order to perform a preliminary assessment of heat stress at work. METHODS: This research included six phases (i) Item generation (ii) Content validity (iii) Reliability analysis (iv)Structure validity (v) Concurrent validity and (vi) Classification of thermal risk level. In item generation phase, 40 items were identified to have impact on the heat strain. Content validity was evaluated by occupational health specialists. RESULTS: In consistency assessment, Cronbach's coefficient (α) of items was 0.91. Exploratory factor analysis on items HSSI draft identified four subscales which explained 71.6% of the variance. Correlation between the HSSI score with aural temperature was 0.73. Cut-off point; sensitivity and specificity for upper no thermal strain zone were 13.5, 91% and 50%, respectively. Whereas Cut-off point, sensitivity and specificity for lower thermal strain zone were 18, 86% and 73%. CONCLUSIONS: The results showed that 18 variables that were measurable through subjective judgment and observation in the HSSI scale covered heat stress key factors. This scale demonstrated reliability and initial validity in scale were suitable. Therefore HSSI scale for primary evaluation heat stress is appropriate.