Arsenic Groundwater Contamination and Sufferings of People in North 24-Parganas, One of the Nine Arsenic Affected Districts of West Bengal, India

Abstract

To understand the magnitude of the arsenic calamity in West Bengal, a detailed study spanning 7 years was made in North 24-Parganas, one of the nine arsenic affected districts. Area and population of North 24-Parganas district are 4093.82 sq. km and 7.3 million, respectively. Fourty eight thousand and thirty water samples were analyzed from hand tubewells of North 24-Parganas in use for drinking, cooking and 29.2% of the tubewells were found to have arsenic above 50 µg/L, the maximum permissible limit of World Health Organization (WHO) and 52.8% have arsenic above 10 µg/L, WHO recommended value of arsenic in drinking water. Out of the 22 blocks of North 24-Parganas, in 20 blocks arsenic has been found above the maximum permissible limit and so far in 16 blocks people have been identified as suffering from arsenical skin lesions. From the generated data, it is estimated that about 2.0 million and 1.0 million people are drinking arsenic contaminated water above 10 µg/L and 50 µg/L level, respectively in North 24-Parganas alone. So far, in our preliminary study 33,000 people have been examined at random from arsenic affected villages in North 24-Parganas and 2274 people have been registered with arsenical skin lesions. Extrapolation of the available data indicates about 0.1 million people may be suffering from arsenical skin lesions from North 24-Parganas alone. A sum of 21,000 hair, nail, and urine samples analyses from arsenic affected villages show 56%, 80%, and 87% people have arsenic in biological specimen more than normal/toxic (hair) level, respectively. Thus, many may be subclinically affected. Due to use of arsenic contaminated groundwater for agricultural irrigation, rice and vegetable are getting arsenic contaminated. Hence there is an additional arsenic burden from food chain. People from arsenic affected villages are also suffering from arsenical neuropathy. A followup study indicates that many of the victims suffering from severe arsenical skin lesions for several years are now suffering from cancer or have already died of cancer.

Keywords:

• North 24-Parganas district
• Arsenic above 10 and 50 µg/L
• Arsenic in food chain
• Arsenic neuropathy
• LOAEL and NOAEL
• Arsenical skin lesions

Acknowledgement

The authors thank Shankar Dey, Bijan Pal, Pijush Ray, Manik Pal, Shibu Pal, Rahul Amin, and Nakuleshwar Pal for their extensive help in the field survey. The authors also thank Gautam Das, Shikha Chowdhury, Shyamal Biswas, Anup Sarkar, and Ashok Das of Gaighata Science Organisation, Gaighata, North 24-Parganas, West Bengal for field survey. Financial support from School of Environmental Studies, Jadavpur University is greatly acknowledged.