Arsenic contamination in Ground Water in India

Arsenic is a naturally occurring trace element found in rocks, soils and the water in contact with them. Arsenic has been recognized as a toxic element and is considered a human health hazard.

Effect of Arsenic on human health

Long-term intake of arsenic contaminated water leads to arsenic poisoning or arsenicosis, with cancer of skin, bladder, kidney or lung or diseases of skin (colour changes, and hard patches on palms and soles), or blood vessels of legs and feet. Fresh evidence indicates possible association between intake of contaminated water to onset of diabetes, hypertension and reproductive disorders.

Absorption of arsenic through the skin is minimal and thus hand-washing, bathing, laundry, etc. with water containing arsenic do not pose human health risks.

World Health Organisation’s provisional guideline value for arsenic in drinking water - 0.01 mg/l (10 μg/l). Permissible limit of arsenic in India in absence of an alternative source - 0.05 mg/l (50 μg/l).

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Arsenic contamination in groundwater

The occurrence of Arsenic in ground water was first reported in 1980 in West Bengal in India. In West Bengal, 79 blocks in 8 districts have Arsenic beyond the permissible limit of 0.05 mg/l. The most affected areas are on the eastern side of Bhagirathi River in the districts of Malda, Murshidabad, Nadia, North 24 Parganas and South 24 Parganas and western side of the districts of Howrah, Hugli and Bardhman. The occurrence of Arsenic in ground water is mainly in the aquifers up to 100 m depth. The deeper aquifers are free from Arsenic contamination.

Apart from West Bengal, Arsenic contamination in ground water has been found in the states of Assam, Bihar, Chhattisgarh, Haryana, Jharkhand, Karnataka, Punjab and Uttar Pradesh. The occurrence of Arsenic in the states of Bihar, West Bengal and Uttar Pradesh is in alluvial formations but in the state of Chhattisgarh, it is in the volcanic rocks exclusively confined to N-S trending Dongargarh- Kotri ancient rift zone. It has also been reported in Golaghat, Jorhat, Lakhimpur, Nagaon, Nalbari, Sibsagar, Sonitpur districts of Assam

The map showing Arsenic hot spots (Hot spots are locations where the arsenic concentration in ground water sample is more than the permissible limit of BIS, 0.01 mg/ L) in India is shown below.

Districts having Arsenic (between 0.01 to 0.05 mg/ litre) in Ground Water in different states of India

Districts Having Arsenic (>0.05mg/litre) in Ground Water in Different States of India

Locations Having Arsenic between 0.01 to 0.5 mg/litre in Ground Water in Different States/ UT of India

Management of Arsenic contamination in groundwater

Some of the management options include

1. Uses of surface water sources
2. Exploring and harnessing alternate arsenic free aquifer
3. Removal of arsenic from groundwater using arsenic treatment plants/filters
4. Adopting rainwater harvesting/ watershed management practices.

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