Policy for Solving the arsenic Problem in Bangladesh Talk at DCH conference February 15th 2004 by Richard Wilson Mallinckrodt Research Professor of Physics Harvard University

Progress has been Painfully Slow! This should not be surprising. Organization is the biggest Bangladesh problem and the one in which NGOs and foreigners can help..

I will argue that there are several potential solutions (1) Household purification (2) well switching (3) Deep wells (4) Dugwells (5) Pond sand filters (6)Rainwater collection (7) large scale purification (a) tube well water (b) river water

Feroze Ahmed Discussed these in the 2002 WHO conference I argue that: Each one has problems which need strong community involvement for their succesful implementation

(1) Household filters PROPOSED 5 Years Ao By DCH among others Abandoned because Household were found unable to manage them They produced solid waste

(2) Well switching Early Optimism Based on Poisons 70% of tubewells are arsenic free It is claimed that the purity gets worse. Is this because: (a) Measurements are bad? (b) They degrade Columbia University Scientists found that it worked in their area

(3) Deep tube wells Cheaper than many others Works Fine for Dhaka Fine in Harvey/Feroze Ahmed studies Fine in Columbia University area Fear that they may not be grouted properly They may degrade with large scale use These fears can be avoided if there is a commitment for yearly measurements and for those areas where they dont work to do something else.

(4) Sanitary Dugwells DCH and in Pabna region and Meera Smith in West Bengal have extensive positive experience Must be properly built and regularly maintained

In some places, shallow dugwells have got more depleted with time. Some critics of dugwells claim that this will inevitably happen to dugwells too. Yet (unsanitary) dugwells have been used for centuries, and DCH, Chariborti and Smith see no problems. Being open to the air is a difference. There is an urgent need to clarify this definitively

(5) Pond Sand Filters Not expensive Seems obvious Difficulty in keeping sanitary I know of no extensive experience

(6) Rainwater collection A centuries old solution. It gets expensive for 9 month storage Must be maintained to keep sanitary

(7) Large scale purification (a) from arsenic laden water Useful for larger communities Cost can be modest At present central facility Piping water to house can be done

(7)Large scale purification (b) from river water Useful for larger communities (10,000 and up) Less complex than getting rid of arsenic and therefore cheaper Trial systems but very slow implementation

TIME SCALES WE need community involvement DCH produced pure piped water to 7000 people. Next year they want to multiply this by 3. Their capability is probably saturated if they go beyond a factor 0f 10 In 5 years that is 350,000 people With 20 NGOs that becomes 7,000,000 Others will follow an the government can buy some larger scale purification systems

WHICH of the 7 approaches? There is no need to specify Each NGO does the system it knows best The Government does the larger scale units for larger communities

BUT : Which stem must be regularly monitored to ensure no degradation We still do not know for sure the reliability of the measurement devices