Measurement of Radionuclides and Gamma-Ray Dose Rate in Soil and Transfer of Radionuclides from Soil to Vegetation, Vegetable of Some Northern Area of Pakistan Using γ-Ray Spectrometry

The analysis of gamma emitters natural radionuclides, i.e., 226 Ra, 232 Th, and 40 K, has been carried out in soil, vegetation, vegetable, and water samples collected from some Northern area of Pakistan, using gamma-ray spectrometry. The γ-ray spectrometry was carried out using high-purity Germanium detector coupled with a computer-based high-resolution multi-channel analyzer. The activity concentrations in soil ranges from 24.7 to 78.5 Bq kg −1 , 21.7 to 75.3 Bq kg −1 , and 298.5 to 570.8 Bq kg −1 for 226 Ra, 232 Th, and 40 K with the mean value of 42.1, 43.3, 9.5, and 418.3 Bq kg −1 , respectively. In the present analysis, 40 K was the major radionuclide present in soil, vegetation, fruit, and vegetable samples. The concentration of 40 K in vegetation sample varied from 646.6 to 869.6 Bq kg −1 on dry weight basis. However, the concentration of 40 K in fruit and vegetable samples varied from 34.0 to 123.3 Bq kg −1 on fresh weight basis. In vegetation samples, along with 40 K, 226 Ra, and 232 Th were also present in small amount. The transfer factors of these radionuclides from soil to vegetation, fruit, and vegetable were also studied. The transfer factors were found in the order: 40 K > 232 Th ≈ 226 Ra. The analysis of water samples showed activity concentrations values for all radionuclides below detection limit. The internal and external hazard indices were measured and found less than the safe limit of unity. The mean value of outdoor and indoor absorbed dose rate in air was found 64.61 and 77.54 nGy h −1 , respectively. The activity concentrations of radionuclides found in all samples during the current investigation were nominal. Therefore, they are not associated with any potential source of health hazard to the general public.