Chemistry Reference
In-Depth Information
17
Chromium - Induced DNA Damage
and Repair
Laura G. Little and Kent D. Sugden
17.1 Introduction
17.1.1 Chromium as a Carcinogen and Current Exposure Limits
Chromium was fi rst used as a commercial chemical in the early 1800s.
1
Since that
time, chromium has found an ever increasing use in a wide range of industrial proc-
esses. These include commercial leather tanning, pigment production, corrosion
inhibition, chrome plating, wood preservation, photoengraving, lithography and fi re-
works production.
2
It was not until the late 19th century, however, that the hexavalent
oxidation state of chromium - Cr(VI) or chromate-containing chemicals were noted
as a potential human health hazard. Scottish chrome pigment workers began report-
ing a large number of nasal tumours presumably caused by the inhalation of chro-
mate dust.
3
By the 1930s, epidemiological studies in Germany had noted a link
between Cr(VI) exposure and the development of lung cancers.
4
These fi ndings were
later confi rmed by studies in the United States,
5 - 7
United Kingdom,
8 - 11
Germany,
12
Italy
13
and Japan.
14
Compounds containing Cr(VI) are now listed as Class 1 human
carcinogens by the International Agency for Research on Cancer (IARC)
15
and as a
Group A airborne human carcinogen by the US EPA due to their presence in a
number of occupational settings.
16 - 18
Safe exposure limits for Cr(VI) compounds are
still being adjusted as new information becomes available. In 1992, the drinking
water standard for total chromium was lowered to 0.1 ppm, due to the emergence of
