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Arsenic
is an important environmental contaminant, being number
ONE in the EPA (Environmental Protection Agency) Superfund
list.
The degree of human sufferings caused by arsenic is
beyond comprehension in some other parts of the world, such as in Bangladesh
and West Bengal, India where an estimated
50 million people are at risk from drinking arsenic contaminated
water.
Arsenic's cancer-causing properties may stem from
the production of DNA-damaging particles called free
radicals.
The finding supports the use of antioxidants such
as vitamin C and vitamin E,
which mop up free radicals,
in cancer prevention.
Researchers studied the effects of arsenic on cells
grown in the laboratory.
Cells exposed to
arsenic produced about three
times as many damaging free radicals
as other cells, the authors report, and an antioxidant cut the level of
free radicals in the arsenic-exposed cells by half.
Arsenic exposure also doubled the number of cells
with genetic mutations, the researchers note. And when an antioxidant
blocker was added to the mix, mutated cells increased by 5 to 16 times.
Studies have already shown arsenic to be a human carcinogen,
but before this study, the way arsenic caused cancer was unclear.
These results, however, clearly demonstrate that
the generation of free radicals
within minutes of arsenic exposure can lead to gene mutations and death
of the cell, the authors conclude, and that antioxidants
can block those effects.
Proceedings of the National
Academy of Sciences February 13th 2001;98:1643-1648
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