Dear All:

On January 6, 2002 Dr.Subangshu Acharya in his post [to arsenic-source, see
http://groups.yahoo.com/group/arsenic-source/message/162 ]indicated that on July
13, 2001 [in a post to Setubanbhan] he clarified and answered the questions
raised by Dr. Thomas Bridge and myself regarding the reduction and oxidation
mechanism for releasing arsenic into the groundwater of Bangladesh and West
Bengal of India.

I have reviewed his post of July 13, 2001 in which I could not find any logical
explanation and factual evidence that he answered the questions.

In his post of January 6, 2002 he did not even present any scientific
explanation that rejected the oxidation theory and supported the reduction
theory for the mobilization of arsenic into groundwater of Bangladesh and West
Bengal of India. His explanations are based on misconception and improper
judgments.

However he fully agrees with me that there is a need of systematic discussion on
the source and the cause of arsenic poisoning because the people of Bangladesh
and West Bengal of India are confused about what is really causing this problem.
We believe the arsenic poisoning in Bengal Basin is a recent, and the largest
man-made disaster in the history of human civilization whereas Dr.Acharya,
Bhattacharya et.al., Ross Nickson et.al. and BGS investigators believe that
arsenic poisoning in Bengal Basin has been present for thousands of years.

Dear all, we have been debating the oxidation/reduction issue for the last few
years. Dr. Bhattacharya and Mr.Ross Nickson claim to be the pioneers of
oxyhydroxide reduction theory (in the context of Bengal Basin) but none of them
came up with any answer(s)/explanation(s) regarding the questions raised by Dr.
Bridge and myself as of yet. These are professional questions and the answer to
these questions will give us a clear idea about the source and the cause of
arsenic disaster in Bangladesh and West Bengal of India and solution to this
problem.

Dear scientists, journalists, environmental activists and people of Bangladesh
and West Bengal of India, I strongly believe that without the help of the
international community no one can solve this problem. The solution to the
arsenic disaster in Bangladesh and west Bengal of India is a very expensive
matter. In order to get help from international community we need to provide
them with right information regarding the source and the cause of poisoning.
Wrong theories and improper judgments can not solve this problem. We have to
establish the source and the cause of poisoning based on reliable data and
factual evidence.

In my next post I will respond to Dr.Acharya's post of January 6, 2002 and today
I would like to make brief comments on his post of July 13, 2001 and invite you
all to participate in this discussion. This discussion will help us to
understand what is needed to be done to determine the source and cause of
arsenic disaster and solution to the problem.

Dr.Acharya in his post stated that, "You have envisaged a combination of
oxidation related to drawdown of water table and reduction during following wet
season in your model. Oxidation can be operative only for very shallow wells.
Whereas, you consider that oxidation is the major cause, that do not follow from
your analysis but from strong 'belief.'"

Dr. Acharya, like all other opponents of oxidation theory, rejected the theory
based on the concept of low sulfate concentration in groundwater and presence of
insignificant amounts of arsenic bearing minerals, but they do not like to
consider/examine the other conditions of the oxidation mechanism and they do not
like to apply proper hydrological and hydrogeological and hydrochemical data and
principles, as a result they have failed to understand the role of oxidation
mechanism for releasing arsenic into groundwater.

Dr. Acharya does not consider the presence of arsenic bearing mineral in the
sediments as reported by Roy Chowdhury et.al. (Nature 1999). I could not find
any logic behind his consideration. Roy Chowdhury et.al's findings are based on
112 wells and 2235 samples whereas Dr. Acharya's justification is based on 25-65
samples from 4 wells only.

In order to verify/justify the findings of Roy Chowdhury et.al., Dr. Acharya
needs to collect "split samples." It appears that he did not collect any split
samples from any of Roy Chowdhury's wells and without collecting and analyzing
he can not state that arsenic bearing minerals are not present in West Bengal
and he can not refute Roy Chowdhury's findings. This is absolutely wrong and
unscientific judgment.

If Dr. Chakraborti does not have enough samples to share with him, then he
should provide Dr. Acharya with a map showing the location of wells and depth of
samples. In Bengal Basin, the change of litho-facies is a common phenomenon.
If Dr. Acharya drill/install wells a foot apart or very close to that of Roy
Chowdhury's wells and collect samples from the same depth he may find similar
samples as that of Roy Chowdhury et.al. The analysis of these samples will
present whether Roy Chowdhury's data are correct or not.

On 12-12-2000, in response to Dr.Achary's comment regarding the oxidation
mechanism Dr. Chakraborti stated "Our samples were also cross-checked by USGS,
USA (Ref. Dr. Alan H. Welch, USGS, Carson City, Nevada). However this does not
mean pyrite oxidation is the only reason of groundwater arsenic contamination in
West Bengal and Bangladesh. We wrote in all our publications pyrite oxidation is
one of the possibilities and we have identified (and cross-checked by various
laboratories) and can say without any doubt after analyzing thousands of samples
the presence of arsenic-rich pyrite in sediment samples of W. Bengal"

Since Dr. Acharia does not believe Roy Chowdhury's data, he should verify the
cross examined data by USGS and other laboratories as indicated above by Dr.
Chakraborti. If these cross examined data are available with Dr. Chakraborti,
I would request him to share these data with Dr. Acharya and us.

Finally, I would like state that even if Dr. Chakraborti's data appears to be
wrong, I am confident if the other conditions of oxidation mechanism are
examined, the complete investigation will prove that arsenic bearing minerals
were present in the sediments prior to the water diversion from rivers and over
pumping of groundwater.

The opponents of oxidation theory did not conduct any detail investigation to
verify the validity of oxidation mechanism and without doing that they have
rejected the oxidation theory and proposed the Oxyhydroxide reduction theory
which is a wrong and misleading theory for the mobilization of arsenic into
groundwater of Bangladesh and West Bengal of India. Therefore, Oxyhydroxide
reduction theory is not an acceptable theory for the mobilization of arsenic
into groundwater of Bangladesh and west Bengal of India.