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.

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 categories at 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 mumol/mol creatinine in the normal work week, and depended on the work category. The particulate PAH exposure ranged from 0.6 to 21.4 micrograms/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 respiratory mask, work category and age.

Correlation between urinary 1-hydroxypyrene and ambient air pyrene measured with an inhalable aerosol sampler and a total dust sampler in an electrode paste plant.

The aim of this study was to investigate whether the use of an inhalable aerosol sampler would improve the correlation between urinary 1-hydroxypyrene and occupational pyrene exposure compared to measurements with a total dust sampler in an electrode paste plant. PAHs were collected on a filter and adsorbent by a 37-mm closed-face total aerosol sampler and an open-face sampler for inhalable aerosol from the Institute of Occupational Medicine (IOM). 1-Hydroxypyrene in pre- and post-shift urine samples was quantitated by high performance liquid chromatography (HPLC). In this study, the use of the IOM sampler resulted in approximately four times higher concentrations of particulate PAH and pyrene than the total dust sampler. The correlation between pyrene levels measured with the two samplers was good with a correlation coefficient of 0.83. The correlation between workplace air pyrene and 1-hydroxypyrene in post-shift urine was poor (r = -0.12), but a small non-significant improvement was found with the IOM sampler (r = 0.11). In this factory the use of an inhalable aerosol sampler had only marginal effect on the correlation between 1-hydroxypyrene in urine and breathing zone pyrene. These results indicate that skin exposure is an important route of PAH uptake in this plant.

Comparative study of an inhalable and a total dust sampler for personal sampling of dust and polycyclic aromatic hydrocarbons in the gas and particulate phase.

For many years the closed-face plastic cassette has been widely used for monitoring 'total' dust in working atmospheres. In the late 1980s a different personal sampler was developed at the Institute of Occupational Medicine in Edinburgh. This so-called IOM sampler was designed to meet the criteria for inhalable dust (EN 481). In this work, a comparison of the closed-face 25 mm Gelman total dust sampler and the IOM inhalable sampler was made for exposure measurements of dust and PAHs among workers in an electrode paste plant. The two samplers were modified in order to permit sampling of both particulate and gas-phase PAHs. Three groups with different tasks were examined. The particle size distribution was determined using personal inhalable dust spectrometers and the GRIMM particle counter. The results showed that higher concentrations of dust and particulate PAHs were measured with the IOM inhalable sampler than the Gelman total dust sampler and the difference between the samplers was significant. This is in agreement with previously reported studies. In some samples collected with the IOM sampler very large particles were observed. There was no significant difference between volatile PAHs measured with the two samplers. For semi-volatile PAHs a significant difference between the samplers was observed, which was ascribed to evaporation loss from the filters during storage.