en Radiation Biology Radiation Biology تحقيق بديع Original Research <strong>Introduction:</strong> Investigation on the natural radionuclides 238U, 232Th, 40K and natural fallout radionuclide 210Po in the prominent plants species of Western Ghats tropical forest near Kotagiri have been carried out as a part of baseline background radiation studies in the forest environment. <strong>Materials and Methods:</strong> The prominent plants species of the region Evodia roxburghiana and Eleaocarpus oblangus were chosen and concentrations of 238U, 232Th, 40K and 210Po were measured by employing gamma ray spectrometer and alpha counter. <strong>Results:</strong> The radioactivity concentrations in plants and soils reflect the impact of the existence of igneous nature of rock in the area of study. Concentration ratios (CR) of these radionuclides, between plants and underlying soil, have been studied and results shows that the concentration ratios (CR) seem to be depend on radionuclides in soil. <strong>Conclusion:</strong> From careful analysis of the results, these Plants could be used as an indicator to monitor these radionuclides. Primordial radionuclides, Western Ghats, monazite, igneous rock, CR -concentration ratio. 195 202 http://ijrr.com/browse.php?a_code=A-10-1-257&slc_lang=en&sid=1 P.K. Manigandan pkmgs@yahoo.com 79003194753284600911 79003194753284600911 Yes N.M. Manikandan 79003194753284600912 79003194753284600912 No