Study on radioactivity in foodstuff for assessment of radiation doses for public at large

Abstract

A study \\la, eontluctetl 10 delemlin~ Jctivity concentration of 'IlK, 20in,112pb, 114pb, 214H't~, ~iAe, 2J~Ra, 23-'Th, 1IOrb. "'r 0, noRa and 2JSU I' n JriOdotl cOlmnon y consume by popuhltion of Bangl8desh, A total of270 diet ."alllpl~~were collceted from the 6 divisions of Bang18desh, The dietary intakes of l2iRu, mIh. 210pb, mpo. mRa and 2JiU were computed basing on the measured activit} of these radionl1e1ide, for estimJtioll of Internal doses, The diet samples have been analp,ed by gamma-ray spectrometry, The gamm8-ray spectrum was recorded 1I,ing a PC based 4096 channel anal}zer and processed by [mca Plus softwarc. rhe elJictenC} of the detector was determined experimentally u~ing stil1uhml radioactive sources. The lower detection limits at 95% conlidenc~ kvd for 10000 s of counting timc and 250 g sample weight were found to be 134 Bqlkg for 40K0.82 Uq for m'Ra, 1.94 Bq for 22iRa, 0.21 Bq for mIh, 0,69 Bq for liOPb. 1.3lBq for 210pOand 0.69 Hq for mU. TIle 8nalytical mcthod employed for the analysis of diet samples wa~ ksted for its reliability through (he analysis of the IAEA ~ertjfied rer"eren~ematelials, Tile statistical paramder:s .weh as mean, median, mode, stand"rd devi8tion, range, skewncss and kurtosis wcre analyzcd. The lrequency distributions Or'28Ra, 210pb, ll"PO, "IK, 226Ra. 1.12'1 hand !'iU werc tcsted nO'the 5apilO-Wilk test. In addition to this, the correlation!. hdween wK ami m'Ra. mIh and 22r'l?a,,J~U and 2l6Ra, 2J1Th ami "'K. 2J8U antl WK. IJlTh and 2)iU were computed from tile re~uhs of thc eOlleentrali'Jn of the radionuc!ide'. A Illoderately good correlation was unserved between 2J~U and ,26Ra: Where<l8Illf other cases the observed correlations were vv'eak.The activity concentration of "'K varies Ii-om 20.5 to 346 I1q,kg" with a medilln value 109 Bq.kg", The corrcspDntlillg v~hJ~' for the rmlionuclides 2.\21h, ~J~1u26.Ra,2IOPO.1lOPbantl ~l~Rawere found to vmy IrOlll 0.01 (00.75 Bq.kg.l with a median ofO,llBq,kg.I, f!'OmOJ)1 tu 1.56 Bq.kg" with a median 01'0.37 Uq.kg.l; from O,OJ (02.30 Bq.kg.l with a median of 0.43 Bq.kg'l. I;-om 0.02 10 4,20 Uq,kg"' with a median of 0.74 J3q.kg.l; from 0.01 to 156 Uq,kg,L with a median of {J.J(J Bq.kg" am! from O,O! to 6,78 Bq,kg" with a IIlctlian or 0,% IJq.k{', The mean activity of the radiolluclitle~ 'l'K, mTh, 2J3U. 22i>Ra.2lIIpo, ""Ph and -'1'I{a werc \21:t61 13q,kg',I 0.1310.10 Rq kg',I 0.4310.31 Bq,kg', I 0.501 0,42 Bq.kg,l. 0,8910.73 Bq,kg,l, 0,3910,33 I:Iq,kg" al\ll 1.I6:tO.92 Bq.kg'l rcspectively, Dietary illl"kes of Ihe Hldionuclides have also bccn cvaluatcd in the \'iork. The daily intakcs from food consumption in I3q arc 121 (,uK),' 0,13 (mIh), 0.41 (mU), U.51 (l2('Ra).1l XI e,ul'oUJ,41 (JIOph),md Ll4e2!Ra). Annllal committed effective doses resulting from I-ycar ingestIon have been estimatcd in the work fh'm Ihe annual intake of12!Ra, 1J"lh, )l°ph, llUpO, 226Raand lJ&Uactivitics, The lesults thus obtained \'iCI'C279 )1Sv, 10 f'S\', 100 flSv. 67 fISV. 52 flSV and 6 flSv re~pectivelJ' The population weighted annual comrnined elfective dose calculated from these mdionuclides was 514 IISV, 'Ihc largest dO,le deli\'ered was by mRa (54.2X%); "ther cOlltrihulinl,; ones Wele mIh (l.(}5%). 210Pb (19.45%), IIVpO (13,03%), 126Ra (10,1 1%) and 2J3U(1.17%). The dala presenled here would be useful to formulate the dose limitlo[ the population of Banglmlcsh.