Title: FW: [globalnews] Ganges, Bengal Delta arsenic crisis: 36 million drinking contaminated water, 150 million at risk
Asia's arsenic crisis deepens
Another Indian state succumbs to well water poisoning.
15 February 2003
TOM CLARKE
http://www.nature.com/nsu/030210/030210-14.html
New cases of arsenic poisoning in India's Ganges Basin suggest that a
crisis in the sub-continent could extend much farther than previously
thought1. Untold numbers of the region's 449 million residents could be
exposed to dangerous levels of the element in their drinking water.
In the mid-1990s it emerged that arsenic has contaminated well water in
parts of the Bengal Delta. This is the coastal floodplain of numerous
rivers, including the Ganges and is shared by Bangladesh and the Indian
state of West Bengal. The latest surveys estimate that around 36 million
people in the Bengal Delta are drinking contaminated water, and 150 million
are at risk.
The new finding suggests that the Bengal Delta "may be only the tip of the
iceberg", says epidemiologist Dipankar Chakraborti of Jadavpur University
in Kolkata. He is calling for urgent region-wide water-well analysis. "The
arsenic problem intensified during a period of long neglect. Our earlier
mistakes must not be repeated," he says
Calling cards
Tipped-off to a spate of cancer deaths and skin lesions in the village of
Semria Ojha Patti in the Indian state of Bihar, Chakraborti's team sampled
wells in the village. Half contain five times the accepted safe limit of
arsenic; 1 in 5 wells have 30 times the safe level.
Many villagers are suffering from the classic skin lesions and neurological
problems of arsenic poisoning. Preliminary evidence also suggests that
mothers who have drunk from contaminated wells have unusually high rates of
miscarriage and premature delivery - another of arsenic's calling cards.
The situation in Semria Ojha Patti is alarmingly similar to that of the
villages in West Bengal and Bangladesh where, as in Bihar, hand-pump wells
have been dug to provide drinking water that is free of waterborne
diseases. Unfortunately the wells tap into natural accumulations of arsenic
swept down from the Himalayas and deposited in the silty aquifers of the
Ganges Basin.
Bihar is 500 kilometres west of the Bengal Delta and is geologically akin
to much of the Ganges Basin. Arsenic-rich deposits could cover much of the
Basin, stretching across the foot of the Himalayas from New Delhi to the
Bay of Bengal.
Countless rural villages with hand-pump wells could be affected, warns
Chakraborti. Last year, arsenic-contaminated groundwater was reported in
Nepal, some 200 kilometres to the north of Semria Ojha Patti, and there are
unconfirmed reports of arsenic in the water in Chandigarh, north of New
Delhi. Only comprehensive surveys will reveal the extent of the problem.
Unfortunately there is a general lack of awareness of the symptoms of
arsenic poisoning - residents of Semria Ojha Patti were being treated for
skin disorders. The best treatment for chronic arsenic poisoning is
removing the source. Arsenic-laden sediments are patchy, so relocating
wells around a village can ameliorate the problem.
Delta watch
"What seems to be emerging is that the correct geological conditions for
arsenic release into groundwater occur widely in delta areas," says
geochemist Andrew Meharg of the University of Aberdeen, UK.
The new finding suggests that similar arsenic contamination in Vietnam,
Thailand and Taiwan could also be more widespread, suggests Meharg.
"Wherever people look, they seem to find arsenic elevation in these deltaic
aquifers," he says.
References
Chakraborti, D. et al. Arsenic groundwater contamination in middle Ganga
Plain, Bihar, India: A future danger?. Environmental Health Perspectives,
published online, doi:10.1289/ehp.5966 (2003). |Article|
