Low Dose Linearity and Hormesis for Radiation

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Transcript Low Dose Linearity and Hormesis for Radiation

The arsenic Catastrophe:
An outsider’s update
Dhaka Community Hospital
Wednesday January 4th 2006
comments by
David Christiani
Professor Harvard Medical School and
Harvard School of Public Health
Richard Wilson
Mallinckrodt Research Professor of Physics
Harvard University
1998 (DCH conference)
urged immediate action:
(1) Measure every well
Green for OK
Red for dont use
Encourage well switching
(2) Purify Water at House level
with simple equipment
(3) Encourage deep wells
(below clay layer)
(4) Keep accurate data and
make them publicly available
(5) Encourage solutions that
lead to the long term
Progress has been slow
Yet international funds
(World Bank, Kuwait Fund)
can be available to GoB
if requested clearly
Problem is probably
local implementation
Difference in cost
between options is
NOT the issue
Labelling wells was
only partially successful
30% of people switched wells
67% switched after a massive
education campaign
Most important step so far.
10 million people have
better water.
Continue education
Emphasize major efforts in
villages with no good well
Uncritical use of Arsenic
Removal Systems (ARS)
has been a disaster.
In West Bengal several hundred
have been installed.
80% are not functional.
(6th report: Jadavpur University
John Macarthur (UCL) agrees.)
DCH tests give only small reduction
NOT a long term solution
(Grainger Prize and US National Academy of
Engineering notwithstanding)
Deep wells may be fed from
the Himalaya further north.
Badly installed wells could bring
water down from upper aquifer.
Some locations (Jessore?)
aquifers may not be distinct
Many have been
Aquifer could be depleted
Measure arsenic levels
frequently, understand
Making data and
information available has
been unsatisfactory
International websites
(arsenic.ws, ACIC.com)
depend upon information
supplied locally
Government sites have
not beendated and kept
up to date.
The APSU site may
solve these problems
Bangladesh Policy
Use surface water when
We must avoid bacteria
and know we have avoided
Rainwater Collection
Improved (sanitary) Dugwells
Pond Sand Filters
River Sand Filters
Key is reliable measurement
and making them available
Cheapest when a large number
supplied from one unit
Many wells have been
abandoned as unsatisfactory
No evidence that they were
properly constructed
Dhaka Community Hospital
has been installing
Sanitary surface “dugwells”
WHO standards;
villagers involved
clear instructions to custodian
Pumped to tank and pipeline
to give running water
Why is it taking so long?
Where is the bottleneck?
Maybe the set up of
village committees
Go at once to tank and
pipeline even though
more expensive
Villagers (especially
women) like it
Early measurements
from DCH looked good.
Recent measurements (with
different equipment) look
This is crucial for
understanding how often
disinfectant , lime or
chloride, must be used.
The whole job can be
done for
ONLY $300 million!
30 cruise missiles!