Article Text

Download PDFPDF
Exposure assessment in the hard metal manufacturing industry with special regard to tungsten and its compounds


OBJECTIVES To assess the exposure to tungsten, cobalt, and nickel in a plant producing hard metals. The main components of hard metals are tungsten carbide and cobalt metal. According to recent studies, these two components may be responsible for both fibrogenic and carcinogenic effects.

METHODS 87 workers were investigated (86 male, one female) with a median age of 42 (range 22–58) and a mean duration of exposure of 13 years (range 1–27 years). Stationary and personal air sampling, and biological monitoring were carried out.

RESULTS Ambient monitoring yielded maximum tungsten concentrations of 417 μg/m3 in the production of heavy alloys. A maximum cobalt concentration of 343 μg/m3 and a maximum nickel concentration of 30 μg/m3 were found at the sintering workshop. The highest urinary cobalt concentrations were found in the powder processing department. The mean concentration was 28.5 μg/g creatinine and the maximum value was 228 μg/g creatinine. The maximum nickel concentration in urine of 6.3 μg/g creatinine was detected in the department producing heavy alloys. The highest tungsten concentrations excreted in urine were found in grinders and had a mean value of 94.4 μg/g creatinine and a maximum of 169 μg/g creatinine. Due to the different solubility and bioavailability of the substance, there was no correlation between the tungsten concentrations in air and urine on a group basis.

CONCLUSIONS Despite its low solubility, tungsten carbide is bioavailable. The different bioavailability of tungsten metal and tungsten compounds has to be considered in the interpretation of ambient and biological monitoring data in the hard metal producing industry. The bioavailability increases in the order: tungsten metal, tungsten carbide, tungstenate. Only if both monitoring strategies are considered in combination can a valid and effective definition of high risk groups be derived.

  • tungsten
  • cobalt
  • biological monitoring

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.