Biological monitoring of tungsten (and cobalt) in workers of a hard metal alloy industry

Objectives To evaluate a combined biomonitoring
approach based on both cobalt and tungsten determination
in workers of the hard metal alloy sector.
Methods We enrolled 55 workers from a factory producing
cutting tools for carpentry. Combined workroom air
and biological monitoring of both cobalt and tungsten
relied on inductively coupled plasma mass spectrometry
determinations. Metals were determined on plasma, blood
and urine samples. Urine samples from 34 unexposed subjects
were also analyzed.
Results Tungsten was determined in every collected sample.
Workers showed signiWcantly higher urinary tungsten
levels than controls (pre-shift values of 4.12 vs. 0.06 g/l
on average; P < 0.0005). Both airborne and biological
levels of tungsten prevailed among workers involved in
wet-grinding activities. The element was excreted at higher
urinary levels than cobalt and showed lower circulating
(blood, plasma) concentrations. Exposure–dose relationships
were apparent for tungsten biomarkers.
Conclusions Obtained results may contribute to the
development of biomarkers of exposure to tungsten. The
association of such biomarkers to traditional determinations
of cobalt in blood and/or urine may substantially improve
the exposure assessment of workers employed in cemented
carbide industries.