Aim: The internal and external exposure of
workers to tungsten, cobalt and nickel in
a cemented carbide processing plant was
investigated. In this context, possibly workrelated
adverse effects on the health of the
workers, especially respiratory tract impairment
were also assessed.
Method: The study group was comprised
of 31 workers with an average age of 31
years who had been employed in the facility
for 124 months. The external exposure to
tungsten was determined after air sampling
by inductively-coupled plasma mass spectrometry
(ICP-MS). Biomonitoring for tungsten
in blood and urine was also carried out
by ICP-MS, while cobalt in blood and cobalt
and nickel in urine were analysed by graphite
furnace atomic absorption spectrometry
(GF-AAS).
Results: The median tungsten concentration
in the workplace air was 0.18 mg/m3 with the
highest levels in the powder processing area
(0.45 mg/m3, maximum: 4.46 mg/m³). The
tungsten concentration in the workers’ blood
was 0.7 μg/l (range: 0.1–15.2 μg/l). The tungsten
concentrations in post-shift urine samples
varied between 0.2 μg/l and 11.0 μg/l
(median: 1.6 μg/l). The cobalt concentration
was 1.7 μg/l in blood and 16.2 μg/l in
post-shift urine, the nickel concentration in
urine was 2.5 μg/l (median values). The workers
were exposed to concentrations of the
metals which generally decreased from the
powder processing area across the sintering
hall to the finishing workshop. Respiratory
impairment and disorders were monitored
as possible reactions. Neither lung function
tests nor chest x-ray and computed tomography
revealed alterations indicative of
hard-metal-induced lung fibrosis.
Conclusions: In general, the employees were
exposed to comparatively low levels of tungsten,
cobalt and nickel. The present study of
workplaces where the refined milling technique
was used revealed no conspicuous
differences in external and internal exposure
from exposures in workplaces using conventional
grinding techniques.
