Assessment of Radionuclides, Trace Metals and Radionuclide Transfer from Soil to Food of Jhangar Valley (Pakistan) Using Gamma-Ray Spectrometry

Abstract

The gamma spectrometric analysis of soil and essential foodstuffs, e.g., wheat, millet, potato, lentils and cauliflower, which form the main component of the daily diet of the local public, was carried out using high purity germanium (HpGe) detector coupled with a computer based high-resolution multi-channel analyzer. The activity concentration in soil samples for 226Ra, 232Th and 40K ranged from 30.0 Bq kg−1 to 81.2 Bq kg−1, 31.4 Bq kg−1 to 78.25 Bq kg−1 and 308.8 Bq kg−1 to 2177.6 Bq kg−1, with mean values of 56.2, 58.5 and 851.9 Bq kg−1, respectively. The average activity measured for 226Ra, 232Th and 40K in soil samples was found higher than the world average. The major radionuclide found in the food items studied was 40K, while 226Ra, 232Th and 137Cs were detected in very nominal amounts. The results clearly indicate that these radionuclides have no health hazard to human beings, as they are well below the annual limit of intake (ALI) for these radionuclides. The transfer factors of these radionuclides from soil to food were also studied. The mean transfer factors of 40K, 226Ra, 232Th and 137Cs from soil to food were estimated to be about 0.17, 0.07, 0.16 and 0.23, respectively. An artificial radionuclide, 137Cs, was also present in detectable amount in all samples. The internal and external hazard indices were measured and had mean values of 0.70 and 0.55, respectively. Absorbed dose rates and effective dose have been determined in the present study. Concentration of trace metals, such as Cr, Pb, Ni and Zn, was also determined in the soil samples. The concentrations of radionuclides and trace metals found in these samples during the present study were nominal and do not pose any potential health hazard to the general public.