The effect of work practices on personal exposure to glutaraldehyde among health care workers.

Glutaraldehyde is a potential sensitizer and has been implicated in the literature as a cause of respiratory irritation and asthma among health care workers. In order to evaluate the effect of work practices and general ventilation system on employees' peak exposure to glutaraldehyde, 42 breathing zone personal air samples were taken in five hospitals. In addition, work practices were observed and recorded during the course of sampling and were classified into three categories. Presence of local or general ventilation system, air change per hour, and quantity of glutaraldehyde used were also recorded. Geometric mean concentration of all samples was 0.025 ppm (GSD=3.05). Statistical analysis indicated that work practice was the most important factor affecting the level of exposure to glutaraldehyde. In locations where "poor" or "unsafe" work practices were employed, the geometric mean concentrations were much higher (GM=0.05, GSD=2.11 and GM 0.08, GSD=1.52, respectively). The result has indicated higher prevalence of headache and itchy eyes among employees who worked where unsafe work practices were observed. Employing proper work practices can significantly reduce exposure to glutaraldehyde among health care workers. It has been recently proposed that the current occupational exposure limit of 0.2 ppm shall be reduced to either 0.1 or 0.05 ppm in the province of Québec (Canada). In this case, it is likely that concentration levels higher than these levels be experienced in some workplaces. Therefore, it is imperative that employers initiate necessary corrective action immediately.

Mineralogical and exposure determinants of pulmonary fibrosis among Québec chrysotile miners and millers.

OBJECTIVES: Lung fibre content was determined for 86 former chrysotile miners and millers in two Québec mining regions: Thetford mines (TM) and the Asbestos region (AR). METHODS: Fibres were assessed using transmission electron microscopy (TEM) and energy dispersive X-ray spectrometry (EDS). Asbestos body (AB) concentrations were assessed by microscopy of tissue digests. Corresponding histological lung tissue sections were quantitatively graded for the severity of interstitial fibrosis on a 12-point scale. Fibrosis score and its associations with (1) fibre concentrations and fibre dimensions within three fibre length intervals (less than 5 microm, 5-10 microm, and over 10 microm), and (2) several exposure variables were evaluated using correlation coefficients and regression techniques. RESULTS: Concentration of short (<5 microm) tremolite fibres was the best predictor of fibrosis grade in both mining groups (r=0.44, P<0.01 and r=0.39, P<0.01 for TM and AR, respectively). Chrysotile fibre concentration showed a lower correlation with the fibrosis grade for subjects from TM only. Long (>10 microm) amosite fibre concentration showed a linear relationship with the fibrosis score in miners and millers from AR. Exposure variables, including smoking, had no predictive value for fibrosis grade. Within fibre length categories, fibre dimension was not related to the fibrosis score. CONCLUSION: Lung fibre concentration as measured by TEM/EDS, especially that of short (<5 microm) tremolite fibres, is a better predictor of fibrosis grade in these two groups of chrysotile miners than either the concentration of ABs or the duration of exposure. Due to the limitation of our counting method, almost all fibres longer than 10 microm observed in this study were shorter than 14 microm. Thus, if length plays a role in fibrogenesis, it may be related to fibres of greater length than those covered in this study.