Study of radon exhalation rate and natural radioactivity in soil samples collected from 50m away from Kasimpur thermal power plant

In the present study, about 20 samples of soil were collected about 50 m away from Kasimpur Thermal Power Plant to investigate the effect of fly ash spread out from the plant on the nearby soil. Can technique using LR-115 type II solid state nuclear track detector has been employed for the measurement of radon activity and radon exhalation rate. Radon activity for soil samples from inside of the Kasimpur Thermal Power Plant, varies from 4657.14 to 4714.29 Bq m-3 with an average value of 4685.72 Bq m-3 ,exhalation rate varies from 1674.35 to 1694.90 mBq m-2 h-1 with an average value of 1684.63 mBq m-2 h-1 and effective dose equivalent varies from 197.44 to 199.86 µSv y-1 with an average value of 198.65 µSv y-1, while from a distance of 50m away from power plant, radon activity varies from 2148.57 Bq m-3 to 4905.71 Bq m-3 with an average value of 3840.75 Bq m-3 , exhalation rate varies from 772.46 mBq m-2 h-1 to 1763.72 mBq m-2 h-1 with an average value of 1380.84 mBq m-2 h-1 while effective dose equivalent varies from 91.09 µSv y-1 to 207.98 µSv y-1 with an average value of 162.83 µSv y-1.Natural radioactivity in soil samples collected from a distance of 50m from Kasimpur Thermal Power Plant has been measured by low level gamma ray spectrometer. Activity concentrations were found to vary from 24.82 ± 0.68 to 241.55 ± 3.39 Bq kg-1 with an average value of 72.19 ± 1.44 Bq kg-1 for 238U, from 37.97 ± 1.3 to 97.22 ±2.16 Bq kg-1 with an average value of 68.81 ± 1.73 Bq kg-1 for 232Th and 99.73 ± 1.53 to 710.72 ± 8.56 Bq kg-1 with an average value of 517.89 ± 6.54 Bq kg-1 for 40K. Radium equivalent activity (Raeq) due to the presence of radio nuclides varies from 86.09 to 415.68 Bq kg-1 with an average value of 206.84 Bq kg-1. Total absorbed gamma dose rates in the surrounding air are found to vary from 38.56 to 191.23 nGy h-1 with an average value of 96.51 nGy h-1. Indoor and outdoor annual effective dose rate from these soil samples changes from 0.19 to 0.94 mSv y-1 and 0.05 to 0.23 mSv y-1 respectively. External hazard index, Hex for the soil samples studied in this work range from 0.23 to 1.13 with mean a value of 0.57. Internal hazard index Hin varies from 0.3 to 1.79 with an average value of 0.76.