Experts from Punjab Agriculture University (PAU) have identified specific regions in Punjab, notably a belt across Nawanshahr and Hoshiarpur districts, as having seleniferous soil. This condition, characterized by an excess of selenium in the earth and groundwater, poses a significant risk of selenium toxicity, detrimental to both human and animal health.
Mapping the Selenium Contamination
In response to this geo-genic issue, PAU is creating detailed GIS digital maps based on soil and water samples collected from the affected region. This initiative aims to precisely delineate areas with high selenium concentration. The concern gained wider attention earlier this year following reports that grains distributed through the public distribution system in Maharashtra contained excessive selenium, with the produce reportedly sourced from Punjab.
While PAU experts clarify that it cannot be definitively confirmed if those specific grains originated from Punjab or a particular selenium-rich patch, the university has been proactively studying the problem for several years. Dr. Sumita Chandel, a soil chemist at PAU's Department of Soil Science, stated that their research focuses on identifying affected zones, mapping selenium levels, and developing practical management strategies for the farming community.
The Double-Edged Sword of Selenium
Dr. Chandel explained the delicate balance of selenium, noting it is a beneficial micronutrient for crops, animals, and humans, but only within a very narrow range. The safe limit in soil is 0.5 parts per million (ppm). Levels exceeding this threshold lead to toxicity, while concentrations below it can result in deficiency.
A PAU study pinpointed that selenium toxicity is primarily prevalent in parts of Nawanshahr and Hoshiarpur. The issue came to light when farmers approached the university after observing the leaves of their wheat crops turning a whitish color. Subsequent testing confirmed selenium toxicity. Wheat is particularly sensitive to this condition, whereas paddy remains largely unaffected.
The excess selenium not only reduces crop yield but also infiltrates the food chain through grain, fodder, and drinking water. "The groundwater in these areas contains elevated selenium. When this water is used for drinking, irrigation, or for growing fodder, animals start losing hair and nails. Similar symptoms can appear in humans as well," Dr. Chandel elaborated. She emphasized that the problem is natural in origin, stemming from the region's geological composition, and is not linked to fertilizer use or industrial pollution.
Practical Solutions for Farmers
PAU has framed actionable solutions to mitigate the impact. For agricultural management, the application of gypsum has shown positive results. "Adding gypsum to wheat or fodder crops helps reduce the adverse effects of selenium in soil. About 350–400 kg per acre should be added in seleniferous soil," advised Dr. Chandel. Farmers who have adopted such in-situ soil management practices have reported fewer problems.
Crop selection is another crucial strategy. Farmers in affected areas are advised to opt for less sensitive crops like maize, sorghum, and bajra. Dr. Chandel recommended that crop choices must be made carefully and suggested that agroforestry could also serve as a sustainable alternative in these seleniferous regions.
