Arsenic poisoning of groundwater: a way to supply arsenic-free water
to the community
Dr Richard Anstiss, Abdul Wakib Khan, Dr Chandra Arewgoda and Prof Mushfique
Ahmed
The New Zealand-Bangladesh Bilateral Development Program
Arsenic contamination of groundwater has reached a state of calamity
in Bangladesh. A large number of people in Bangladesh have been suffering,
and many of them are dying from arsenicosis and related complications.
Making use of arsenic adsorption on ferric oxyhydroxide and settling, we
found it optimal to add modest quantities of pre-precipitated ferric oxyhydroxide
in well-head treatment tanks to obtain efficient enough adsorption (As<0.05
ppm) to be of practical use by people using water regularly from the tanks
(<100 litres). This simple low-cost procedure produces some arsenic-rich
ferric oxyhydroxide, however the volume of drinkable water produced is
substantial, and arsenic adsorption and settling are relatively fast. During
the 1998-99 dry season we - members of the New Zealand-Bangladesh Bilateral
Development Program - will be implementing a three year arsenic removal
pilot program in Chapainawabganj, a severely arsenic contaminated district
in northwest Bangladesh (where maximum arsenic concentrations can be as
high as 2.4 ppm). It is hoped that with a combination of such water treatment
and prudent well management integrated with a public health program, this
large-scale crisis in Bangladesh can be tackled successfully.
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