| Toxicity: |
Human exposure occurs occupationally and via
food, tobacco smoke, ambient air, and water. Three major
groups of arsenic compounds have been defined on the basis
of biological considerations: inorganic arsenicals; organic
arsenicals; and arsine (gas). The comparative toxicity of these
groups is dependent upon the route of exposure and their solubilities;
the more quickly absorbed compounds have lower
LD50. Arsenic is readily absorbed by the respiratory and gastrointestinal
systems and is concentrated in the skin, hair, and
nails (Aldrich-Mees’ lines). The cellular toxicity of arsenic is
related to reactions with SH-containing mitochondrial enzymes
that result in impaired respiration. Arsenic may also compete
with phosphate during oxidative phosphorylation. |