Policy for Solving the arsenic Problem in Bangladesh

Talk at DCH conference

February 15th 2004by

Richard WilsonMallinckrodt 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 switchingEarly 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