Speaker
Kumar Niranjan
(North-Eastern HilL University Shillong Meghalaya)
Description
A radiation dose and risk assessment exercise was carried out for the edible biota, Garra lamta, Brassica compestris var. dichotoma, Oryza sativa var.Shalum1 and Zea mays due to the naturally available radionuclide 40K, 238U and 232Th in Domiasiat ecosystem of Meghalaya, India. A detailed morph-physiological study of biota and the eco-geo-physiographical study of ecosystem had been carried out prior to the dose -risk assessment. The activity in biota and the corresponding soil and water sample was measured for the 12 months by precipitation method using NaI detector. The total activity of water was 0.3447 Bql-1 by the precipitation method using the 34.2% detector limit and 3000 second counting time having detection limit of 0.03 Bql-1.The foremost point source dose distribution (source↔target) method and the recently developed FASSET were investigated in details. Garra lamta was modeled using the former method whilst others uses FASSET and was concluded that deviation amongst two was negligible. The obtained transfer factor (TF) was Oryza spp. (1.00E-01- 40K, 8.76E-05- 232Th, and 9.11E-05- 238U), for Brassica spp. (5.39E-01- 40K, 8.17E-04 232Th and 2.96E-04 238U) and for Zea spp. (3.41E-01-40K, 5.84E-05-232Th and 8.87E-05-238U) of each radionuclide respectively. The obtained total dose was 1.58E-04 in Oryza spp., 2.87E-04 in Brassica spp. and 6.90E-03μGyh-1 in Zea spp. and in Garra lamta 0.0199μGyh-1 finally compared with IAEA and UNSCEAR dataset for the screening level dose for the fish (0.022-0.065) ,flora (0.1-1.0 mGyd-1) of fresh water and forest ecosystem respectively. Zea spp. was found comparatively more susceptible for chronic radiation exposure.
Author
Kumar Niranjan
(North-Eastern HilL University Shillong Meghalaya)
