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ARSENIC CONTAMINATION IN BANGLADESH
Groundwater
contamination by arsenic was first discovered in the west of
Bangladesh in late 1993 following reports of extensive
contamination of water supplies in the adjoining areas of India.
A World Bank Fact Finding Mission visited Bangladesh in April
1997 to assess the situation and to initiate a mitigation
program. Part of their recommendations included a broad-ranging
rapid Investigation Program to collate the available data, fill
in critical gaps in knowledge and undertake surveys of the
affected area. This eventually led to the project entitled
�Groundwater Studies for Arsenic Contamination in Bangladesh�
which was approved by the Government of Bangladesh in late
December 1997. The UK Department for International Development
(DFID) agreed to finance the project.
The
symptoms of chronic arsenic poisoning may take between five and
fifteen years to reveal themselves. The principal treatment is
to provide the patient with arsenic-free drinking water. The
Bangladesh Standard for arsenic in drinking water is 0.05 mg/l.
This standard was based on World Health Organization (WHO)
advice at the time when the regulations were drafted. In 1993
WHO lowered their guideline value for arsenic to 0.01 mg/l. This
value has not been adopted in either Bangladesh or India.
Arsenic is both toxic and carcinogenic. Inorganic forms of
arsenic dissolved in drinking water are the most significant
forms of natural exposure. Organic forms of arsenic that may be
present in food are much less toxic to humans. Clinical
manifestations of arsenic poisoning begin with various forms of
skin disease, and proceed via damage to internal organs
ultimately to cancer and death.
The
Department of
Public Health Engineering (DPHE), which is responsible for
water supply throughout the country other than in the cities of
Dhaka and Chittagong, is the executing agency for the project.
The Bangladesh Water Development Board (BWDB) and the Geological
Survey of Bangladesh (GSB) also provided counterparts for the
study. On behalf of the Government of Bangladesh, DFID appointed
the British Geological Survey (BGS) as lead consultants for the
study. BGS appointed Mott MacDonald Ltd (MML) to carry out much
of the Phase 1 work. A team of national experts was recruited to
assist with the work.
Maps:
Percentage of ground
waters from the shallow aquifer (less then 150 m deep) exceeding
the Bangladesh standard for arsenic of 0.05 mg/l
Population per square km exposed to arsenic greater then 0.05
mg/l
The project began in mid January 1998 and was structured to have
a six month Phase 1 and an eighteen month Phase 2 with about
half the funding allocated to Phase 1. The principal aims of
Phase 1 were to: (i) collate and review existing data for
arsenic in Bangladesh ground waters; (ii) carry out a regional
survey of arsenic in ground waters in what was believed to be
the worst-affected parts of Bangladesh (approximately the
southern and eastern two-thirds of Bangladesh); and (iii) to
carry out a more detailed study of three small areas (thanas) to
assess the possible source, mobility and fate of arsenic in the
aquifers. Phase 1 was due to be completed in July 1998 but was
delayed due to the need to reanalyze all of the 2000 regional
survey samples in the UK. The arsenic analyses were completed in
October 1998, and the draft final report was submitted for
review in November. This delay did not prevent the start of
Phase 2 work, and a number of Bangladesh sediments have now been
analyzed for arsenic and other elements.
Sources:
- Government of the People's Republic of
Bangladesh
- Ministry of Local Government, Rural
Development and Cooperatives
- Department of Public Health Engineering
- UK Department for International
Development (DFID)
-
British
Geological Survey, http://www.bgs.ac.uk/hydro/b_intro.htm
A simple home-made
filter to remove arsenic from water
Women decanting
water treated by a pitcher filter
Alternative to
tubewell water: a pond sand filter
Special Article : Arsenic Risk
Management : Need for a Comprehensive Strategy
Read more about
arsenic pollution in
www.sdnbd.org
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