Estimation of radiological risk due to concentration of ^{238}U, ^{226}Ra, ^{232}Th and ^{40}K in soils of different geological origins in northern India


Abstract: Radioactivity of nuclides ^{238}U, ^{226}Ra, ^{232}Th and ^{40}K was measured in soil by \gamma-ray spectrometry using a HPGe detector. A criterion was set in order to analyse soil samples from plain, semi-hilly and hilly areas in northern India. More than three \gamma-ray energy peaks were used for the determination of ^{226}Ra and ^{232}Th activity concentrations to obtain more accurate results. Some of these peaks have interfering energies, which was caused by the limited resolution of the detector, but they were resolved theoretically and used in the analysis because of their significance in reducing the random error to its minimum level. Relationships between the measured radionuclides have been discussed elaborately. Radionuclides ^{238}U and ^{226}Ra were found in disequilibrium with ratio of specific activities (^{238}U/^{226}Ra) less than unity for most of the samples. In some cases this disequilibrium may be significant enough to modify the \gamma -ray dose factors.

Keywords: Soil, natural radionuclides, disequilibrium, dose

Full Text: PDF