Chemistry Reference
In-Depth Information
18
Arsenic - Induced Carcinogenicity:
New Insights in Molecular
Mechanism
Andrea Hartwig and Tanja Schwerdtle
18.1 Introduction
Arsenic is a well-documented human carcinogen after both oral exposure and inha-
lation. While environmentally relevant arsenic species include inorganic as well as
organic arsenicals, elevated cancer incidences have been attributed to inorganic
arsenic, and research has focused on identifying the underlying mechanisms. A
variety of inorganic arsenates or arsenites occur in water, soil and food, while the
most common inorganic arsenical in the air is arsenic trioxide (As
2
O
3
). In general,
trivalent arsenites tend to be more toxic than pentavalent arsenates; however, in
many cases mixed exposure towards trivalent and pentavalent inorganic arsenic
occurs and the precise chemical speciation is usually not known.
1,2
Regarding world-
wide public health, the most important medium for inorganic arsenic exposure is
drinking water, causing many types of cancer and a wide range of further adverse
health effects, including neurotoxicity, liver injury and the endemic 'blackfoot
disease ' .
3 - 6
Furthermore, occupational exposure is still relevant, even though the use
of arsenicals has been restricted in industrialized countries considerably during
recent years.
