Renal and immunologic markers for chloralkali workers with low exposure to mercury vapor.

Objectives: The aim of this study was to investigate renal function and immunologic markers among chloralkali workers with long-term low exposure to mercury vapor.
Methods: Forty-seven currently exposed workers were compared with reference workers matched for age in a cross-sectional design.
Results: The mean urinary mercury concentration was 5.9 (range 1.1-16.8) nmol/mmol creatinine (Cr) for the exposed workers and 1.3 (range 0.2-5.0) nmol/mmol Cr for the referents. The chloralkali workers had been exposed for an average of 13.3 (range 2.8-34.5) years. The activity of N-acetyl-beta-D-glucosaminidase in urine (U-NAG) was higher in the exposed workers (mean 0.18 U/mmol Cr versus 0.14 U/mmol Cr, P=0.02). Associations between current urinary mercury, cumulative urinary mercury, and cumulative urinary mercury per year (intensity) and U-NAG, autoantibodies to myeloperoxidase (anti-MPO) and proteinase 3 in serum, respectively, were observed. The activity of U-NAG and anti-MPO was increased in the workers with the highest exposure, as assessed by their mean intensity of exposure. The highest activity of U-NAG was observed in the exposed workers with the lower concentrations of selenium in whole blood.
Conclusions: The study indicates an effect of exposure on the kidney proximale tubule cells, possibly modified by individual selenium status, and an effect mediated by neutrophil granulocytes.