New Delhi, Sep 17 (UNI) Nearly 16 million people in 79 blocks in eight districts of West Bengal are facing the risk of consuming arsenic affected ground water in the country, an official release said.
The occurrence of arsenic in ground water was first reported in 1980 mainly in West Bengal. The water was found to contain arsenic sporadically beyond the permissible limit of 0.01 mg/L as per Bureau of Indian Standards.
The most affected districts were on the eastern side of Bhagirathi River in the districts of Malda, Murshidabad, Nadia, North 24 Parganas and South 24 Parganas, and the western side of the river districts of Howrah, Hugli and Bardhman.
In all cases, high arsenic is also associated with high iron. The occurrence of Arsenic in ground water is mainly in the intermediate aquifer between 20-100m. The deeper aquifers were free from Arsenic contamination but the tubewell had to be designed with proper cement sealing to prevent percolation from above arseniferous aquifer.
Apart from West Bengal, arsenic contamination in ground water has also been found in the State of Bihar, Chhattisgarh and Uttar Pradesh. In case of Bihar, 12 districts have been reported with contamination of ground water.
The occurrence of Arsenic in the states of Assam, Bihar, West Bengal and Uttar Pradesh have been associated with Alluvium soil formation, but in Chhattisgarh, it is associated with volcanic formation, the release added.