Risk assessment of radioactivity in soils of forest and grassland ecosystems of the Western Ghats, India

Abstract

Naturally occurring radionuclides were investigated in soil samples collected from a tropical rainforest in the Western Ghats, India. For comparison, a number of soil samples from nearby meadows (open grassland) were also studied using gamma-ray spectrometry. Average values of the activity concentration of radionuclides, outdoor gamma-ray dose rate, annual effective dose equivalent and radiation hazard indices from soil activity were estimated. Significant differences were found between the soils from the forest and meadow sites: the meadow sites contained higher natural radionuclide concentrations than the forest sites. The activity concentration of 232Th and average outdoor gamma-ray dose rates were found to be higher than the global average in both ecosystems, so high gamma radiation appears to affect the Western Ghats environment. Therefore, the radiological risks to the general population from ionizing radiation from the naturally occurring radionuclides in the soil are considered to be significant. However, other radiological hazard indices that were calculated were within acceptable limits.