The effect of dust-protective respirator mask and the relevance of work category on urinary 1-hydroxypyrene concentration in PAH exposed electrode paste plant workers

Abstract

Large amounts of polycyclic-aromatic hydrocarbons (PAH) are found in the work environment of electrode paste workers. Inhalation and skin uptake are both important routes for PAH exposure. We have studied the effect of dust-protective respirator masks by measuring urinary 1-hydroxypyrene as a biomarker for PAH exposure. Eighteen workers divided into work categoriesat the factory were monitored by personal air sampling and urinary 1-hydroxypyrene every work shift for two consecutive weeks. In the second week of the study, the workers were encouraged to wear respirator masks persistently, which resulted in a significant reduction in urinary 1-hydroxypyrene in end-of-shift samples (paired t-test, P = 0.009). When correcting urinary 1-hydroxypyrene for ambient air pyrene we found on average 41% reduction in urinary 1-hydroxypyrene concentration in the second week of the intervention study. There was a work-category dependent variation in the correlation between end-of-shift urinary 1-hydroxypyrene samples and pyrene measured in the breathing zone of the workers, most likely due to variable skin uptake of pyrene; the overall correlation coefficient was 0.26 (P = 0.015). The 1-hydroxypyrene concentration in pre- and post-shift urine samples varied between 0.7 and 69.6 μmol/mol creatinine in the normal work week, and depended on the work category. The particulate PAH exposure ranged from 0.6 to 21.4 μg/m3. The ratio of particulate pyrene to benzo[a]pyrene varied from 1.6 to 8.0 amongst the various work categories within the same plant. Multiple regression analysis showed that smoking and work day are explanatory variables for the concentration of 1-hydroxypyrene in urine. Thirty-nine percent of the variation in the urinary 1-hydroxypyrene level at the end of shift could be explained by the independent variables pyrene concentration in air, smoking habits, work day, use of respirator mask, work category and age.