en Radiation Biology Radiation Biology تحقيق بديع Original Research <span style="font-weight: bold"> Background:</span> 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. <span style="font-weight: bold">Materials and Methods</span>: 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. <span style="font-weight: bold">Results:</span> 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. <span style="font-weight: bold">Conclusion:</span> From careful analysis of the results, these plants could be used as an indicator to monitor these radonuclides. Primordial radionuclides, Western Ghats, monazite, Igneous rock, CR –concentration ratio. 88 96 http://ijrr.com/browse.php?a_code=A-10-1-278&slc_lang=en&sid=1 P.K. Manigandan pkmgs@yahoo.com 790031947532846001119 790031947532846001119 Yes N.M. Manikandan 790031947532846001120 790031947532846001120 No