Analysis of effective equivalent dose to the organs and cancer risk assessment due to natural outdoor gamma radiation in Eastern Thar Desert, India

Abstract

ABSTRACT The assessment of a population’s radiological impact due to radiation emitted by natural radionuclides is important because it is associated with the health of the people. The objective of the study was to provide reliable baseline data and analyse the impact of the natural outdoor gamma radiation dose of Nagaur, Kheenvasar, and Jayal blocks of Nagaur district, Rajasthan. A total of 80 locations of Nagaur, 31 locations of Kheenvasar, and 51 locations of Jayal were selected for the analysis. The gamma radiation exposure was found to vary from 66 nSv/h to 163 nSv/h, which lies within the normal range specified by UNSCEAR (20 to 200 nSv/h) for all the sites. Statistical analysis through the Shapiro-Wilk test (p < 0.05) rejects the normality of data for all three blocks, which specified the not suitability of data for the parametric test. The Jonckheere-Terpstra test (p < 0.05) confirmed that there was no significant difference among the radiation doses of different blocks. Annual effective dose (AED) and Excess lifetime cancer risk (ELCR) were computed to determine the number of cancer cases originating from outdoor gamma radiation. Average cancer cases due to outdoor gamma radiation were estimated at 49, 45 and 48 per hundred thousand in Jayal, Kheenvasar, and Nagaur blocks, respectively. The Effective Equivalent Dose for Bone-marrow (red), colon, lung, stomach, breast, reminder tissues, Gonads, Bladder, Oesophagus, Liver, Thyroid, Bone surface, brain, salivary, glands, and skin was also calculated and found within the prescribed limit.