Impact of coal power plant emission on the foliar elemental concentrationsin plants in a low rainfall tropical region

A field study was conducted around two thermal power plants of India to qua ntify the changes in foliar elemental concentrations due to emission in a l ow rainfall tropical area. Sulphur dioxide and particulates were at high le vels which may cause serious ecological effects. Emission from the power pl ants has altered the elemental concentrations in the leaves of evergreen an d deciduous plants. The foliar total-S and SO42--S levels were significantl y higher in all the plants growing at polluted sites. However, the organic- S content was more or less unaltered. In evergreen plants, the SO42--S cont ent increased gradually from summer through winter, whereas in the deciduou s plants there was a higher magnitude of increase after onset of new leaves during summer. With the increasing pollution load, foliar Ca2+ and K+ cont ents increased, whereas N content decreased. The reduction in N content was greater during summer in evergreen plants and during winter in deciduous p lants. The plants growing closer to the power plants accumulated more trace elements (Mn, Fe, Cd, Pb and Ni) as compared to those growing at distant s ites. In deciduous plants the leaf fall during winter lowered down the trac e element.