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.