Lucknow, Jun 4 (IANS): Sonbhadra, the second-largest district in Uttar Pradesh, has been found to have an 'alarmingly high' fluoride contamination in groundwater.

High arsenic toxicity has also been found in groundwater in Gonda and Basti districts.

A study conducted by the Geological Survey of India (GSI), northern region, Lucknow has found that the volume of contaminants in groundwater is alarmingly high with values recorded several times higher than permissible limits.

The study was conducted by a team of five geologists led by GSI Director (geology) Abhinandan Srivastava.

In Sonbhadra, GSI took over 200 samples from handpumps and wells. In around 20 villages, fluoride contamination was found double the permissible limits, especially in villages around Govind Ballabh Pant Reservoir.

The presence of high fluoride in groundwater has led to health issues like tooth decay, discolouration and yellowness of teeth, joint pains and dental fluorosis among villagers.

Superintending geologist, GSI, Suparna Hazra, said, "In villages like Jhapar, Siswa, Bichhiari and Pindari, fluoride contamination was found to be 3 milligram per litre (mg/litre), which is double of the permissible limit of 1.5mg/litre as set by the Bureau of Indian Standards."

In three villages, Pipri, Dhaurahwa and Sonwani, an alarming 5mg/litre of fluoride was found in the groundwater, she said.

Meanwhile, in Gonda and Basti, high arsenic toxicity has led to health issues like hyperpigmentation, keratosis on palm and sole and hearing loss.

In Gonda, villages falling in Nawabganj, Tarabganj, Paraspur, Haldarmau and Katra Bajar blocks recorded 20-25 times higher arsenic contamination than permissible limit.

The highest contamination of about 250 parts per billion (ppb) was found at three places-- Gokula village, Bhihanpur Kalan Temple and Gosain Purwa. The acceptable limit of arsenic in drinking water is 10 ppb only.

In Basti, the Captanganj, Bahadurpur and Kudraha blocks recorded high arsenic contamination.

The maximum concentration of 250 ppb has been observed in Agauna village.

GSI has suggested that rainwater harvesting may be practiced and pre-treated rivers may be used for supply to rural households in these areas till the groundwater situation improves.