Cancerous levels are found high in drinking groundwater of 2 districts

Selenium, A Mineral Found In Soil, Can Cause Cancer If Consumed In Excess

Chandigarh: High concentration of selenium in the groundwater has been found in about 50% of the area in Hoshiarpur and Nawanshahr districts of Punjab, posing a serious threat to human health, crops and animals, shows new research.

Selenium, a mineral found in soil, has both benefits and potential health risks. If consumed within the prescribed limit, it boosts immunity, besides other health benefits. However, when consumed in excess, it has carcinogenic effects and is capable of causing cancer.

A study was conducted in Hoshiarpur and Nawanshahr districts to examine the depth-wise variation of sele nium in the aquifers of north-eastern Punjab. For this, three aquifer groups we re identified with groups I, II and III having depth rage of 75-95m, 120-230m and above 255m, respectively.

Groundwater sampling for selenium was carried out at 14 locations and about a litre of groundwater was collected from each sampled tube well after about 30 minutes of pumping for collection of fresh groundwater for chemical analysis.

Out of the 14 groundwater samples collected from tube wells, selenium was not found in five samples, while six samples showed higher concentration of selenium concentrations than the f 0.01 permissible limit mg/L prescribed by the Bureau of Indian Standards, raising concern about the presence of high amount of selenium in aquifers of the study area. In nine samples, selenium levels ranged between 0.0024 and 0.114 mg/L. High concentration of selenium was observed in aquifer groups I and II with concentrations decreasing with depth.

In aquifer group III, which started from a depth of 255m, selenium level was within the permissible limits, pointing out at the need for water supply wells to tap aquifer group III and completely sealing the aquifer groups I and II in the affected areas.

The study titled ‘Depth wise Variation of Selenium in Groundwater in Parts of Punjab, India’ has been carried out by ML Angurala, Central Ground Water Board, North West Himalayan Region, Jammu; Pardeep K Naik, Rajiv Gandhi National Groundwater Training and Research Institute, Raipur; and SC Behra, Central Ground Water Board, South Eastern Region, Bhubaneswar. The findings have been published in the Journal of Geological Society of India.

Experts opined that unregulated withdrawal of groundwater led to a sharp decline in water levels and the symptoms of selenium toxicity started to emerge after tube wells started to tap aquifers below the sandy clay horizon of 20m to 45m and were put to use for irrigation and domestic purposes. Researchers observed: “It is inferred that possibly the use of selenium-rich groundwater from this sandy clay horizon contaminated the surface as well as subsurface soils, resulting in high selenium contents in plants as well. With the decline in water level, deeper tube wells have been drilled piercing through this selenium-rich, sandy-clay horizon, thus spreading selenium contamination in the entire region.”