Study of Radioactivity Levels in Different Kinds of Food Stuff Grown on the Bank of RupshaRriver and its Impact on Human Health

Abstract

The natural environment around us is the prime source of radiation. The activity concentrations of radionuclide have been investigated in the human food-chain. To determine the radioactivity level in the Paddy, Arum, Papaya &Leafy vegetables samples collected from different locations on the Bank of Rupsha River at Rupsha upazialla in Khulna of Bangladesh. In the present study, a total of 6 Paddy, 7 Leafy vegetables, 8 Arum and 7 Papaya samples have been collected from 8 locations of the area under investigation. The samples have been analyzed by gamma-ray spectrometry system using a ‘Hyper-Pure Germanium’ (HPGe) detector of 20% relative efficiency to identify the probable radionuclides, activity concentrations and the radiological risks to human from intake of these crops and vegetables. Natural radionuclides such as 226Ra, 232Th and 40K have been found in the samples and no artificial radionuclide has been detected in any of the sample. The activity concentrations of 226Ra, 232Th and 40K in Paddy samples have been found to be varied from 17.59±4.44 Bq/Kg to 42.32±4.48 Bq/Kg, average 24.43±5.16 Bq/Kg, BDL to 3.745±2.99, average 2.048±2.798 Bq/Kg and 35.97±150.34 Bq/Kg to 170.12±135.49 Bq/Kg, average 93.96±133.75 Bq/Kg, respectively. In Leafy vegetables activity concentrations have been found to be varied from 25.97±11.28 Bq/Kg to 49.11±13.48 Bq/Kg, average 34.22±12.55 Bq/Kg, BDL to 17.075±11.515 Bq/Kg, average 9.84±10.63 Bq/Kg and 626.88±176.34 Bq/Kg to 1378.25±225.93 Bq/Kg, average 1110.50±200.24 Bq/Kg. In Arum samples activity concentrations have been found to be varied from BDL to 8.78±3.08 Bq/Kg, average 5.77±2.97 Bq/Kg, BDL to 2.53±4.32 Bq/Kg and 426.91±107.23 Bq/Kg to 1280.71±133.89Bq/Kg, average 758.298±109.66 Bq/Kg. The activity concentrations in Papaya samples have also been found to be varied from 13.295±9.64 Bq/Kg to 77.96±22.01 Bq/Kg, average 43.31±15.28 Bq/Kg, BDL to 26.2±17.27 Bq/Kg, average 15.44±11.28Bq/Kg and 1112.65±202.33 Bq/Kg to 1712.47±221.96Bq/Kg, average 1490.27±226.27 Bq/Kg, respectively. The annual effective dose of all samples (Paddy, Leafy vegetables, Arum and Papaya) have been found that intake high effective Dose of 226Ra of 349.23 μSv y-1 by Papaya samples and 344.92 μSv y-1 by Leafy vegetables samples. 232Th of 248.29 μSv y-1 by Paddy samples & 40K of 454.90 μSv y-1 by Arum samples. The maximum effective dose of 226Ra (0.39mSv) is high than world safe value (0.12mSv) in Papaya, The effective dose of 40K (0.45mSv) is high than world safe value (0.17mSv) in Arum and 232Th (0.24mSv) is slightly than world safe value(0.12mSv) in Paddy samples. The natural radioactivity concentrations of 226Ra, 232Th and 40K for all samples are higher than the worldwide average values. The current result is slightly higher compared with the results of similar studies undertaken in other countries and in different places in Bangladesh. However, these values of doses are much below the permissible level set by ICRP, and, therefore, there is no immediate health risk on workers and public due to natural radioactivity present in the samples of the study area. Therefore, the results on radionuclide concentrations and annual effective dose have been obtained from this study may provide with interesting information to evaluate the extent, degree and routes of the radiological impact. This study would also be useful as a base line data on radiation exposure and environmental impact caused by crops and vegetables on the Bank of Rupsha River in Khulna of Bangladesh.