The background to what they are doing in Bangladesh and West Bengal =

and why ...

        http://www.bangladesh-selenium.org/documents/La%20Porte%20Phase%20I=
II%20clinical%20trial.pdf


__________________


Background: The Bangladesh Arsenic Crisis

Beginning in 1972, the Governments of Bangladesh and India used UNICEF =

financing to drill 900,000 tubewells
at 20-60m depth throughout the Bengal basin to: a) provide villagers =

with drinking water free from
cholera, typhoid, and dysentery; and b) provide reliable, year-round =

irrigation water for intensive rice
cultivation, as an alternative to the annual but unreliable monsoon =

rains.

Since then, government and private initiatives have introduced a total =

of 8 to 12 million more tubewells in Bangladesh, which now provide 95% =

of
the drinking water for 97% of the population.284

In the 1980s, it was discovered that the alluvial sediments of the
Ganges delta are highly contaminated by arsenic, particularly in the =

shallow aquifers.3 Recent work has
demonstrated that arsenic originates from ferrous oxides in the =

Holocene-era aquifers tapped by the tubewells.
Carbon deposits from ancient mangrove swamps provide reducing =

conditions that cause the release of arsenic
that would otherwise remain trapped in the ferrous oxide crystals.

Arsenicosis was first observed in West Bengal in 1983 by
dermatologist Dr. KC Saha.213 Later, in 1987, it was found in
border-crossing Bangladeshi subjects.214 During the 1980s,
Kolkotta-based researchers led by Dr. D. Chakraborti
discovered 3,000 villages in West Bengal contaminated
about 50 =B5g/L,37 prompting the 1998-99 British Geological
Survey-Bangladeshi government survey of 3,534 wells
throughout Bangladesh. The BGS survey found wide-spread
and severe arsenic contamination, (Figure 1).28 with
estimates that 8.6% of the population drinks at 50-100=B5g/L
As, 10.9% at 100-300=B5g/L As, 4.5% at 300-600=B5g/L As, and
0.83% at > 600=B5g/L As154 The revised WHO and EPA
drinking water limits are at 10 =B5g/L, and toxicity is readily
apparent above 300 =B5g/L. In one Bangladeshi district alone,
an academic group found that 358 out of 375 sampled
tubewells (95.5%) were contaminated by As > 50=B5g/L, with
126 tubwells (33.6%) showing severe contamination by As > 300 ug/l



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