Promotion of well-switching to mitigate the current arsenic crisis in Bangladesh.
OBJECTIVE
To survey tube wells and households in Araihazar upazila, Bangladesh, to set the stage for a long-term epidemiological study of the consequences of chronic arsenic exposure.


METHODS
Water samples and household data were collected over a period of 4 months in 2000 from 4997 contiguous tube wells serving a population of 55000, the position of each well being determined to within +/- 30 m using Global Positioning System receivers. Arsenic concentrations were determined by graphite-furnace atomic-absorption spectrometry. In addition, groundwater samples collected every 2 weeks for an entire year from six tube wells were analysed for arsenic by high-resolution inductively coupled plasma-mass spectrometry.


RESULTS
Half of the wells surveyed in Araihazar had been installed in the previous 5 years; 94% were privately owned. Only about 48% of the surveyed wells supplied water with an arsenic content below 50 micro g/l, the current Bangladesh standard for drinking-water. Similar to other regions of Bangladesh and West Bengal, India, the distribution of arsenic in Araihazar is spatially highly variable (range: 5-860 micro g/l) and therefore difficult to predict. Because of this variability, however, close to 90% of the inhabitants live within 100 m of a safe well. Monitoring of six tube wells currently meeting the 50 micro g/l standard showed no indication of a seasonal cycle in arsenic concentrations coupled to the hydrological cycle. This suggests that well-switching is a viable option in Araihazar, at least for the short term.


CONCLUSIONS
Well-switching should be more systematically encouraged in Araihazar and many other parts of Bangladesh and West Bengal, India. Social barriers to well-switching need to be better understood and, if possible, overcome.
Van Geen
Alexander
A
Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA. avangeen@ldeo.columbia.edu
Ahsan
Habibul
H
Horneman
Allan H
AH
Dhar
Ratan K
RK
Zheng
Yan
Y
Hussain
Iftikhhar
I
Ahmed
Kazi Matin
KM
Gelman
Andrew
A
Stute
Martin
M
Simpson
H James
HJ
Wallace
Sean
S
Small
Christopher
C
Parvez
Faruque
F
Slavkovich
Vesna
V
Loiacono
Nancy J
NJ
Becker
Marck
M
Cheng
Zhongqi
Z
Momotaj
Hassina
H
Shahnewaz
Mohammad
M
Seddique
Ashraf Ali
AA
Graziano
Joseph H
JH
D001151:Arsenic / Q000032:analysis*; D020261:Arsenic Poisoning / Q000453:epidemiology / Q000517:prevention & control; D001459:Bangladesh / Q000453:epidemiology; D004781:Environmental Exposure / Q000032:analysis*; D006801:Humans; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
D014874:Water Pollutants, Chemical; D001151:Arsenic