A precise dose-response-relationship between
chromium (VI) exposure and the
development of lung cancer could not be
demonstrated so far, neither for exposures
in the chromate industry nor for exposures
to welding fumes. There are large statistical
uncertainties due to small numbers of cases,
lack of or insufficient control for smoking
and co-exposures. Because of the strong
correlation between exposures to Cr(VI) and
Cr(III), effects of the two chromium species in
chromate workers cannot be differentiated.
The same is true for chromium and nickel in
welding fumes. A comparatively small but
significant increase in the lung cancer risk
has been observed after welding-fume exposure.
Application of results from the chromate
industry to welders must be viewed
critically because of the different effects and
bioavailability of the various chromium compounds.
Because of the shortcomings of the epidemiological
data, the derivation of a scientifically
based estimate of the dose causing a
doubling of the lung cancer risk is associated
with considerable uncertainty. Thus, a socio-
political consensus would be needed to
establish an dose level for use in a simplified
procedure for the recognition of occupational
diseases. According to our evaluation of the
literature, such a dose could be in the range
of 2000 μg Cr(VI)/m³-years, as proposed by
Norpoth and Popp.
Future scientific evaluation of chromium
effects should address the solubility and
biopersistence of Cr(VI) and Cr(III) compounds
in more detail. Particulate-matter
effects have to be taken into account for studies
in welders, together with co-exposure to
nickel.
