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Objective: Ambient exposure to fine particles is associated with increased cardiovascular morbidity and mortality. Associations between occupational particulate matter (PM) exposure and cardiovascular disease have been studied less. The objective of this study was to examine associations between PM exposure and endothelial function among workers in Norwegian smelters., Methods: We examined endothelial function with Endo-PAT equipment after a working day (WD) and on a day off (DO) in 59 furnace workers recruited from three metal smelters in Norway. The difference in baseline pulse amplitude (BPA) and reactive hyperemia index (RHI) between the 2 days was analysed in relation to individual exposure to PM < 250 nm (PM 250 ) or the respirable aerosol fraction of particles, and adjusted for relevant covariates., Results: The exposure to PM 250 ranged from 0.004 to 5.7 mg/m 3 . The mean BPA was significantly higher on WD relative to DO (772 vs. 535, p = 0.001). This difference was associated with PM concentrations among participants ≥ 34 years, but not among the younger workers. Reactive hyperemia was significantly lower on workdays relative to days off (1.70 vs. 1.84, p = 0.05). This difference was observed only among participants above the age 34. No associations with PM exposure were observed., Conclusions: PM exposure was associated with higher BPA among participants older than 34 years. BPA reflects microvessel pulsatility. Our results may indicate an age-dependent cardiovascular susceptibility to PM exposure. Endothelial function measured by RHI was reduced on WD among participants 34 years and older, but we found no associations between PM exposure and RHI.

Air samples were collected by personal sampling with five stage Sioutas cascade impactors and respirable cyclones in parallel among tappers and crane operators in two manganese (Mn) alloy smelters in Norway to investigate PM fractions. The mass concentrations of PM collected by using the impactors and the respirable cyclones were critically evaluated by comparing the results of the parallel measurements. The geometric mean (GM) mass concentrations of the respirable fraction and the <10 μm PM fraction were 0.18 and 0.39 mg m(-3), respectively. Particle size distributions were determined using the impactor data in the range from 0 to 10 μm and by stationary measurements by using a scanning mobility particle sizer in the range from 10 to 487 nm. On average 50% of the particulate mass in the Mn alloy smelters was in the range from 2.5 to 10 μm, while the rest was distributed between the lower stages of the impactors. On average 15% of the particulate mass was found in the <0.25 μm PM fraction. The comparisons of the different PM fraction mass concentrations related to different work tasks or different workplaces, showed in many cases statistically significant differences, however, the particle size distribution of PM in the fraction <10 μm d(ae) was independent of the plant, furnace or work task.

The hygroscopic behaviour of individual aerosol particles from workplaces in a primary aluminium smelter was investigated by environmental scanning electron microscopy. At a high relative humidity, comparable with the human respiratory tract, most particles encountered in the Søderberg and Prebake potrooms either undergo partial deliquescence (leading to a water droplet with an insoluble core) or form thin water films at the surface. As gaseous HF and SO(2) are highly soluble in water, the aerosol particles may act as carrier for these two gases into the alveolar region of the lower respiratory tract. Based on a one-dimensional mass balance model, it is estimated that under peak exposure conditions (particle surface area concentration of 10(-4) cm(2) cm(-3)) approximately 10% of the initial gaseous HF may be transferred to the particle phase. For SO(2), this fraction is much lower (approximately 1%). These results indicate that at least HF may penetrate deeper into the lung in the presence of soluble particles or particles that form surface water films compared to HF alone.

Biologic monitoring data in electric welders revealed reliable correlation between manganese concentration in the whole blood and manganese concentrations in the workplace air. The chronic manganese intoxication patients showed reliable lower levels of urinary iron, cobalt and manganese vs. those values in the reference group.

Mercury vapour exposure was studied for 40 years in 419 chloralkali workers. The concentration of mercury was measured in the work room (stationary) from 1953 and in urine from 1948. There were major differences in the mean urinary concentrations between different types of job. The mean urinary mercury concentration, uncorrected for urinary dilution, for all subjects varied between 30 and 250 micrograms 1.(-1) during the study period. For workers in the cell-room the correlation (r) between urinary mercury and mercury in the work room was r = 0.74 (P < 0.001), and for repair men/mechanics it was r = 0.70 (P < 0.001). The introduction of new cells and stabilizing the volume of production may have been important for reducing air-Hg and U-Hg, whereas other changes in the production process, or actions to reduce the release of mercury to the work environment, had no detectable effect. The urinary mercury concentration among all workers was related to the relative energy consumption (r = 0.83, P < 0.001).

Chromosome aberrations and micronuclei in peripheral lymphocytes were studied in 29 male chloralkali workers previously exposed to mercury vapor and in two matched reference groups comprising 29 nitrate fertilizer workers and 29 customs and police officers. The study was performed using whole-blood cultures with and without hydroxyurea and caffeine to inhibit deoxyribonucleic acid synthesis and repair, respectively. No significant differences in the frequencies of chromosome aberrations and micronuclei were observed. However, a nonsignificant increase in chromosome breaks and dicentrics was found in the subgroups with high urinary mercury peak levels or high cumulative mercury exposure. An increased prevalence of "high" scores of chromatid breaks in the inhibited cultures, exceeding the 75th percentile of all of the subjects studied, was observed for the chloralkali workers when compared with both reference groups. No evident cytogenetic effects were observed among the chloralkali workers with the methods used in the present study.

Seventeen former chloralkali workers were followed through the regular determination of urinary mercury for nearly two years after the cessation of exposure to mercury vapor in a study of the time course of urinary mercury elimination. Their duration of exposure ranged from 3 d to 35.5 years. A one-compartment model for urinary mercury elimination was applied. The urinary mercury concentration declined at a rate indicating a half-time of 91 d. When corrected for an individual base-line level of urinary mercury resulting from sources of mercury intake not related to work, the half-time was 72.4 [95% confidence interval (95% CI) 63.2-81.7] d, with a mean elimination rate constant of 0.011 (95% CI 0.008-0.013).d-1. The day-to-day variability of the urinary mercury concentration averaged 22%, expressed as the coefficient of variation between urine samples delivered on three consecutive days.

The aim of this study was to investigate the relationship between organic solvent exposure and brain atrophy among 85 patients referred to a department of occupational medicine and who underwent cerebral computed tomography. On average, the patients had been heavily exposed to a mixture of organic solvents for 22.9 years. Diseases which may be associated with brain atrophy or high alcohol consumption was observed among 31% of the subjects. Among these subjects the prevalence of brain atrophy was 58%. The prevalence of brain atrophy was 20% among the men without such conditions. None of the eight female patients appeared to have atrophy. The quantitative assessment showed no correlation between the duration of exposure and atrophy-related parameters. However, the width of the third ventricle, bifrontal ratio, and bicaudate ratio were correlated with age.