Uranium and thorium with their progenies and radioactive isotope of
potassium 40K are the greatest contributor to ionizing
radiation in human environment. In nature, uranium and thorium, have crustal average abundance of 2.7 ppm and 8.5 ppm respectively. Analysis of uranium, thorium and
potassium-40 in crustal materials is very important to estimate their contribution to environmental
radioactivity.
To study distribution of radio nuclides in the soils of Punjab gamma spectrometry technique was used. A total of 12 samples from different parts of the state were collected. The soil samples were collected from a depth of about 12-15 cm and dried in the oven at 100 ºC for 1 hr. Then the samples were sieved through 150 µm mesh and stored in standard plastic containers for one month before counting. Radium-226 has been measured in soil samples instead of uranium-238.
The concentration of radium-226 in the state varies from a minimum value of 18.6 Bq/Kg in Bathinda district to a maximum value of 68.9 Bq/Kg in Amritsar district. Thorium-232 concentration varies from a minimum of 10.6 Bq/Kg for Patiala district to a maximum of 94.2 for Amritsar district. The concentration of potassium-40 varies form 48.8 Bq/Kg in Moga district to 160.1 Bq/Kg in Amritsar district.
The correlation coefficient between the concentration of radium-226 and potassium-40 comes out to be 0.80 while that between concentration between concentration of thorium-232 and potassium-40 is 0.84.