Measurement of radium, thorium, potassium and associated hazard indices from the soil samples collected from Northern India

The presence of radium, thorium and potassium in soil and building materials impose radiological hazards to human population. Both alpha and gamma radiation are produced from the decay chain of uranium and thorium while potassium is itself a source of gamma radiation. The measurement of these radionuclides in soil is important to prevent the general public from health hazards. The measurement of radium, thorium and potassium from soil samples collected from some locations of Northern India was carried out to assess the various radiological hazard indices using sodium iodide-based gamma ray spectroscopy. The observed specific activities of radium, thorium and potassium varied from 13 to 175, 141 to 399 and 276 to 1581？Bq/kg with an average of 78, 231 and 525？Bq/kg, respectively. The mean values from soil samples under study are more than the corresponding worldwide average values (35, 30 and 400？Bq kg？1 for 226Ra, 232Th and 40K) but less than the recommended limits. The measured radium, thorium and potassium activity from the soil samples were used to find out the various hazards index and absorbed dose. The results show the soil of the study area does not pose any health hazards to people residing in this area