Arsenic Poisoning Part-2
Arsenic is a grey-appearing chemical element (atomic number 33, symbol As in
the periodic table) also termed a metalloid. Arsenic can exist in a metallic
state in three forms (yellow, black, and gray; with gray predominating) and in
ionic forms. Arsenic is considered to be a heavy metal, and arsenic toxicity
shares some features with poisonings by other heavy metals. Historically,
arsenic has been used as a medicinal agent, a pigment, a pesticide, and an agent
with intent to harm (use with criminal intent). Up until 2003, arsenic (in the
form of chromated copper arsenate) was used in the US as a treatment to prevent
insect infestation of wood used in building. In 2003 the use of this compound
was banned by the US Environmental Protection Agency.
Arsenic is mixed with
copper or lead to strengthen alloys containing these materials. Arsenic and some
of its compounds react with proteins, mainly the thiol portions, and uncouples
the process of oxidative phosphorylation, thus inactivating most cellular
functions. Consequently, arsenic and some of the substances it combines with are
deadly poisons to most biologic systems, except for a few bacterial species.
Arsenic is used in making insecticides and weed killers. Arsenic is also thought
to be carcinogenic, meaning that it has the potential to
cause
cancer.
Arsenic
can be found as a contaminant in food and water sources. Shellfish and other
seafood, as well as fruits, vegetables, and rice; are the foods most commonly
contaminated. Arsenic poisoning typically occurs as a result of industrial
exposure, from contaminated wine or illegally distilled spirits, or in cases of
malicious intent.
What is inorganic arsenic?
Inorganic arsenic is metallic or metalloid element that forms a number of
poisonous compounds. In industry, it can be found in a gaseous form termed
arsine gas that is very toxic when inhaled. Inorganic arsenic is found in nature
at low levels mostly compounded with oxygen, chlorine, and sulfur. These are
called inorganic arsenic compounds. Inorganic arsenic compounds are much more
poisonous to most biologic systems (animals, plants, humans) than organic
arsenic (see below). Inorganic arsenic occurs in nature in the soil, copper and
lead ore deposits, and water, but usually in low concentrations. However, it can
become more concentrated when industrial processes use it to make wood
preservatives, metal compounds, or organic arsenic-containing compounds such as
insecticides, weed killers, and other compounds. If such compounds are burned,
inorganic arsenic can be released into the air and later settle on the ground or
in water and either remain in the inorganic form or combine with organic
material.