Ganga-Meghna Brahmaputra || West Bengal || Bangladesh || Middle Ganga Plain, Bihar || Uttarpradesh
Jharkhand || North-East Hilly States || Rajnandgaon, Chattisgarh || Behala, Kolkata, WB || As toxicity- Homeopathic Treatment
Effectiveness & Reliability - As Field Testing Kits || Utility Of Treatment Plant
Causes, Effects & Remedies - Groundwater As Calamity || References

Endangered Generations :Groundwater Arsenic Contamination in West Bengal, India

Dipankar Chakroborti
School of Environmental Studies,
Jadavpur University, Kolkata-700 032
Tel: 91 33 24146233, Fax: 91 33 24146266

Arsenic contamination of groundwater and its human consequences in three villages from two districts of the state of West Bengal in the eastern part of India was first brought to attention in 1982. The scale of this disaster has become evident over the past twenty years. During field surveys conducted over the past seventeen years, we have identified 3300 arsenic-affected villages in 9 of the total 18 districts in West Bengal. The danger is still acute. During a preliminary field survey conducted for 4 days in Murshidabad on 18-21 December 2001, we identified 931 new victims with skin lesions caused by arsenic poisoning from 29 villages. Fourteen have suspected cancer and 72 suspected Bowen's Disease. Even after twenty years, the problem is worsening. Many villagers continue to be unaware that they are drinking contaminated water, which is responsible for their skin lesions. Approximately 90% of children below 11 years of age living in arsenic affected villages show hair and nail arsenic above normal level. Infants and children (Photograph 1) might be at greater risk from arsenic toxicity because of more water consumption on a body weight basis.

Yet the Government of West Bengal has steadily ignored or deliberately reduced the extent of this environmental hazard. On 5 April 1999 the Health Minister claimed a substantial improvement in the groundwater arsenic situation from that in 1983. In August 2000 a high-ranking official of the state government told in an international meeting in Bangladesh that West Bengal had only 450 arsenic patients from all arsenic affected districts and that arsenic-free drinking water is supplied to people in the affected areas through a pipeline network. These claims are disproved by scientific and empirical evidence to the contrary. It is my contention in this paper that not only thousands of present sufferers, but countless future generations are still gravely at risk from groundwater arsenic contamination in West Bengal.

Twenty years ago, groundwater arsenic contamination and symptoms of arsenic related ailments were first noticed in patients residing in three villages of two districts in West Bengal. Today, this minor arsenic incident has taken a menacing look simply due to negligence and lack of proper controlling mechanisms. A minimum of 6.5 million people including about 2 million children belonging to 9 out of the total 18 districts of West Bengal were drinking arsenic contaminated water which contains arsenic more than the maximum permissible limit set by WHO (which is 50 µg/l) and about 300,000 are already suffering from arsenic related diseases. About 50 million inhabitants of these 9 districts are at risk from arsenic toxicity. Many people with moderate to severe arsenical skin lesions have been found to develop cancer eventually. Previously, it was thought skin cancer is the common type of cancer caused by arsenic. But lung, liver, colon, bladder etc. cancers have been found among those suffering from chronic arsenic toxicity.

A team of average 15 researchers from Jadavpur University, Kolkata has been engaged for the last 17 years in the task of surveying the magnitude of the arsenic problem in the villages of West Bengal's affected districts. We have analyzed 1,28,303 water samples from 9 arsenic affected districts by Flow Injection Hydride Generation-AAS. Out of the total samples analyzed, 50% are unsafe to drink according to WHO recommended value of arsenic in drinking water (recommended value is 10 µg/l) and 26.7% contains arsenic above WHO maximum permissible limit (maximum permissible limit is 50µg/l). So far we have identified 3285 villages from 85 blocks out of 9 affected districts (Figure 1) where ground water contains arsenic above 50 µg/l and registered 10,000 people from 284 villages with arsenical skin lesions (Table 1).

Table 1: Present Groundwater Arsenic Contamination Status of West Bengal, India

Area in sq. km 89193
Population in million 80
Total number of districts 18
Total number of water samples analyzed 128303
% of samples having arsenic above 10µg/l 50
% of samples having arsenic above 50µg/l 26.7
Number of arsenic affected districts where groundwater contain arsenic above 50 µg/l 9
Area of arsenic affected districts in sq. km 38865
Number of arsenic affected Blocks / Police Station 85
Number of arsenic affected villages (approx.) where groundwater contain arsenic above 50 µg/l 3285
People drinking arsenic contaminated water above 50 µg/l (in million) 6.5
Number of districts surveyed for arsenic patients 7
Number of districts where arsenic patients identified 7
Number of people screened for arsenical skin lesions (preliminary survey) 95000
Number of registered patients with clinical manifestations 10000
% of children having arsenical skin lesions of total patients 1.7
Total hair, nail, urine, skin-scales analyzed 28000
Arsenic above normal level (average) in biological samples 85%
People may be affected from arsenical skin lesions* (approximate) 300,000

*On the the basis of no. of tubewells having arsenic >300 µg/l

But we feel we have been able to survey and bring to light only a negligible amount of the real and menacingly huge proportion of the calamity. With every of our subsequent survey there is an increase of both the number of affected villages and that of ailing persons. During our survey we have noticed that in some villages where a few years before after analyzing the hand tube-wells, we colored the tube-wells green (arsenic < 10 µg/l) and told the villagers to drink the water, a good percentage of those
tube-wells are now no more safe to dink (arsenic > 50 µg/l). Thus with time more and more tube wells are getting contaminated.

Figure 1

This is also true for deep tube-wells. Some time back when we realized it would take us years to find out the actual magnitude of the calamity, we decided to survey in detail 2 out of 9 arsenic affected districts of West Bengal. We have been undertaking a detail survey of North 24-Parganas and Murshidbad for the last 5 and 3 years respectively. This survey is still on.