Mapping natural radioactivity of soil samples in different regions of Punjab, India.

Thallium activated sodium iodide (NaI(Tl)) detector and multi channel analyzer has been utilized to measure gamma rays emitted by radio nuclides found in soil samples of south-west (SW) region of Punjab state, India where elevated level of uranium of around value of 700µg/l in groundwater has been reported. For comparative study, soil samples were also collected and analyzed from west (W) and north east (NE) regions of the state. Uranium and potassium has been found to be comparatively higher in SW region whereas thorium level is higher in W and NE part of Punjab state. Overall concentration level of naturally occurring radio nuclides40 K,238 U and232 Th has been found to be varied from 260.1±17.3 to 728.2±27.7, BDL to 41.9±10.3 and 29.5±7.1 to 88.1±6.2Bq/Kg respectively. Overall average level of40 K and232 Th has been found to be higher as compared to world's average concentration level. Average radium equivalent activity (134.8±23.03 (σ) Bq/Kg), dose rate (61.9±10.3nGy/h), outdoor and indoor dose (0.30±0.05 and 0.08±0.01 mSv/year), external and internal hazard index (0.36±0.06 and 0.42±0.08) has been calculated.