Laboratory studies were conducted to investigate the adsorption/desorption behaviour in alluvial soils of seleniferous and non-seleniferous regions of Punjab. Adsorption of Se by different soils from the equilibrating solutions containing 1 to 100 μg mL−1 could be described by Langmuir and Freundlich equations for the entire range of concentration used in the study. Adsorption maximum was highest for Barwa soil (460.8 μg g−1) from seleniferous region, whereas, binding energy was more for Gurdaspur soil (0.207 mL g−1) from non-seleniferous region. Significant positive relationship existed between adsorption maximum and cation exchange capacity (r = 0.930*) as well as clay (r = 0.986**) content of soils. The amount of Se desorbed in Kel (water-soluble) was relatively higher than desorbed in KH2PO4 (exchangeable) in all the soils except Gurdaspur soil. On an average, water-soluble and exchangeable Se together constituted 78.7 to 95.6 per cent of total adsorbed Se on all the soils.
Selenium, adsorption, desorption, seleniferous soils
