Determination of uranium and polonium in Sparus aurata by alpha spectrometry

Re is a Mexicana de Física ISSN: 0035-001X [email p o ec ed] Sociedad Mexicana de Física A.C. México Luna Po es, M.; Manjón Collado, G.; Díaz, I.; Ren e ía, M.; Mon e o Cab e a, M.E. De e mina ion o u anium and polonium in Spa us au a a by alpha spec ome y Re is a Mexicana de Física, ol. 58, núm. 3, junio, 2012, pp. 224-227 Sociedad Mexicana de Física A.C. Dis i o Fede al, México A ailable in: h p://www. edalyc.o g/a iculo.oa?id=57023406009 How o ci e Comple e issue Mo e in o ma ion abou his a icle Jou nal's homepage in edalyc.o g Scien i ic In o ma ion Sys em Ne wo k o Scien i ic Jou nals om La in Ame ica, he Ca ibbean, Spain and Po ugal Non-p o i academic p ojec , de eloped unde he open access ini ia i e RADIATION PHYSICS Re is a Mexicana de F´ ısica 58 (2012) 224–227 JUNIO 2012 De e mina ion o u anium and polonium in Spa us au a a by alpha spec ome y M. Luna Po es1, G. Manj´ on Collado2, I. D´ ıaz2, M. Ren e ´ ıa1, M.E. Mon e o Cab e a1∗ 1Cen o de In es igaci´ on en Ma e iales A anzados, S.C., Miguel de Ce an es 120, Complejo Ind. Chihuahua, Chihuahua, Chih., M´ exico 2Depa amen o de F´ ısica Aplicada II de la Escuela T´ ecnica Supe io de A qui ec u a, Uni e sidad de Se illa, Espa˜ na. ∗Co esponding au ho : elena.mon e o@cima .edu.mx Recibido el 3 de junio de 2011; acep ado el 4 de eb e o de 2012 The aim o his s udy was op imizing condi ions o he speci ic ac i i ies de e mina ion o some u anium-se ies adionuclides p esen in Spa us au a a by alpha spec ome y. De e mina ions o speci ic ac i i ies we e conduc ed a ying he ype o diges ion: acid a ack on ho pla e, con olled mic owa e diges ion and acid a ack a e calcina ion o he sample. The la e p ocedu e was applied only o he case o u anium iso opes de e mina ion. The a ia ion in he iso ope ex ac ion me hod consis ed o applying he echniques o liquid-liquid ex ac ion using T ibu yl phospha e (TBP) o ch oma og aphic UTEVA esin. Resul s depending on he ype o ea men gi en o he samples we e compa ed based on ob ained chemical yields. The esul s e eal a highe bioaccumula ion o polonium in he li e sample, wi h ac i i ies o 0.809, 2.495 and 2.439 Bq kg−1 esh w compa ed wi h he ille . The bes chemical yields o polonium we e close o 60% o samples ha we e diges ed by mic owa e. In he case o u anium he bes chemical yields, close o 80% o ille , we e ob ained wi h a p e ious calcina ion o he sample and using he UTEVA esin. Keywo ds: U anium; polonium; alpha spec ome y; ish. El obje i o de es e es udio ue la op imizaci´ on de las condiciones pa a la de e minaci´ on de las ac i idades espec´ ı icas de algunos adion´ uclidos de la se ie del u anio p esen e en Spa us au a a po espec ome ´ ıa al a.Las de e minaciones de las ac i idades espec´ ı icas se ealiza on a iando el ipo de diges i´ on: a aque ´ acido en pa illa, en mic oondas y a aque ´ acido despu´ es de la calcinaci´ on de la mues a. Es e ´ ul imo p ocedimien o ue aplicado solamen e en el caso de la de e minaci´ on de los is´ o opos de u anio. La a iaci´ on en el m´ e odo de ex acci´ on del is´ o opo, consis i´ o en la aplicaci´ on de las ´ ecnicas de ex acci´ on l´ ıquido-l´ ıquido u ilizando el os a o de ibu ilo (TBP) o sepa aci´ on c oma og ´ a ica empleando la esina UTEVA. Los esul ados ob enidos en los di e en es ipos de a amien os que se les dio a las mues as, ue on compa ados con los endimien os qu´ ımicos ob enidos. Los esul ados e elan una mayo bioacumulaci´ on de polonio en la mues a de h´ ıgado, con ac i idades de 0.809, 2.495 y 2.439 Bq kg−1de peso esco en compa aci´ on con el ile e.Los mejo es endimien os qu´ ımicos pa a el polonio ue on ce canos al 60% pa a las mues as que se some ie on a diges i´ on po mic oondas. En el caso del u anio los mejo es endimien os qu´ ımicos, ce canos al 80% en ile e, se ob u ie on con una calcinaci´ on p e ia de la mues a y el uso de la esina UTEVA. Desc ip o es: U anio; polonio; espec ´ ome o al a; peces. PACS: 91.62.+g; 89.60.-k. 1. In oduc ion The impo ance o s udying con amina ion le els by hea y me als and me alloids (HMM) in he aqua ic en i onmen is due o he ac ha HMM a ebioaccumula i e, no biodeg ad- able, and may be easily inco po a ed in o he ood chain. This con amina ion may ha e se ious e ec s on human heal h [1,2]. O ganisms wi h me als in hei issues a e o en used o indica e and quan i y he le els o con aminan s o hei bioa ailabili y in he en i onmen . A bioindica o is an o - ganism ha con ains in o ma ion abou he quali y o he en i onmen ; a biomoni o con ains in o ma ion abou he quan i a i e aspec s o he quali y o he en i onmen [3,4]. In he ma ine en i onmen di e en o ganisms such as oys- e s, sh imp and ish [5] ha e been used o con amina ion moni o ing. Fish a e ideal indica o s o pollu ion because hey occupy di e en ophic le els; u he mo e, ish samples a e o di - e en sizes and ages [1]. The up ake o adionuclides by ish depends on a iables such as die a y habi s, loca ion, ish physiology and physical- chemical a iables such as pH, empe a u e and wa e (in- cluding he concen a ion o adionuclides) [6]. The Po-210 en e s he human body ia inhala ion o adon gas Rn-222 and inges ion o ood and wa e , inges- ion o ood being he majo ou e [7]. Ma ine bio a ha e been ound o con ain high concen a ions o Po-210, which is conside ed o be he majo con ibu o o adia ion dose e- cei ed by man (abou 0.11 mS yea −1)[8, 9]. The e o e, many coun ies and se e al in e na ional o ganiza ions ha e de e mined he concen a ions o his adionuclide in sea ood [7].The objec i e o his s udy was op imizing he p ocedu e o he de e mina ion o speci ic ac i i ies o some u anium- se ies adionuclides p esen in Spa us au a a by alpha spec- ome y. This species was selec ed o he p esen s udy because i is a med in almos all Medi e anean coun ies and i s size can a y om 20 o 57 cm. These a e impo an ac o s o DETERMINATION OF URANIUM AND POLONIUM IN SPARUS AURATA BY ALPHA SPECTROMETRY 225 conside ing i as a possible biomoni o o con amina ion by adionuclides. 2. Ma e ials and me hods Fish samples we e ob ained om a local supe ma ke a he ci y o Se ille in Spain .The a ge species was Spa us au a a (commonly known as ”Golden”). Se en ish samples we e used o he adiochemical analysis. Fish sizes a ied om 26 o 28 cm o leng h, o no in oducing size o age as a a iable in ou analysis. 2.1. Sample p epa a ion Be o e dissec ion, he samples we e washed ho oughly wi h dis illed wa e and hen hey we e measu ed and weighed. Subsequen ly he ish we e sepa a ed o analysis in o h ee pa s: li e , edible ille and bone; he weigh s o hese h ee pa s we e eco ded o u he calcula ions. Biological samples we e lyophilized o i e days o ex ac he wa e . Weigh s we e eco ded o ge he mois u e loss and inally, se en samples o each pa o he ish we e combined and homogenized be o e he analysis. 2.2. Radiochemical me hods and measu emen ech- niques Samples we e subjec ed o adiochemical analysis o Po-210, U-234 and U-238. The p ocedu es employed we e p e iously desc ibed [10, 11]. The s anda ds yield ace s used ( om Iso ope P oduc s) we e Po-209 (Ac i i y=172.7±5.2 mBq/g) and U-232 (Ac i i y=117.8±0.6 mBq/g). Alpha spec ome y wi h su ace ba ie silicon PIPS de- ec o s ( om CANBERRA) was he me hod applied o de e - mine he speci ic ac i i ies in ish samples. Gene al p ocedu e o he diges ion o samples is p e- sen ed in Figu e 1. 2.2.1. Polonium de e mina ion A s anda d yield ace Po-209 was added in di e en quan i- ies o ish samples which we e diges ed by mic owa e o ho pla e. Au odeposi ion o polonium was done by using asco bic acid in HCl solu ion, hen solu ion was hea ed o 80oC and Powas spon aneously pla ed on o a o a ing coppe disc. Po- 210 ac i i y was co ec ed o eco e y by compa ison wi h he measu ed ac i i y o he Po-209 yield ace . FIGURE 1. Gene al p ocedu e o sample diges ion. 2.2.2. U anium de e mina ion A s anda d yield ace U-232 was added in di e en quan i- ies o ish samples which we e diges ed by calcina ion o in solu ion wi h a ho pla e. The iso ope ex ac ion me hods applied we e liquid- liquid ex ac ion wi h ibu yl phospha e (TBP) and ch o- ma og aphic UTEVA esin. The iso ope ex ac ion me hods a e based on he me hod ini ially de eloped [12-14]. The men ioned ex ac ion me hods a e p esen ed in Fig- u es 2 and 3. Figu e 3 shows he low diag am o u anium and ho ium ch oma og aphic sepa a ion wi h UTEVA esin. The diges ed sample is pou ed on he esin and hen 5 mL HNO33M is added. The ex ac ion me hod o ho ium and u anium is pe o med sequen ially by adding acids solu ion in concen- a ions shown by he a ows in s ep 3 and 4. U anium was elec odeposi ed om he solu ion on a pol- ished s ainless-s eel disc, using Halls adius me hods [15]. The cell used o his elec odeposi ion is made o e lon which p e en s he adionuclides om adso bing on he wall o he cell [10, 15-17]. FIGURE 2. Liquid - liquid ex ac ion echnique. FIGURE 3. Ch oma og aphic sepa a ion echnique using UTEVA esin. Re . Mex. Fis. 58 (2012) 224–227 226 M. LUNA PORRES, G. MANJ´ ON COLLADO, I. D´ IAZ, M. RENTER´ IA, M.E. MONTERO CABRERA TABLE I. Po-210 ac i i y concen a ions gi en on esh weigh ba- sis, ob ained o di e en ypes o sample ea men and di e en sample issues. F means ille and L means li e . SAMPLES Po-210 YIELDS TREATMENTS (Bq kg−1) (%) S1-F 0.21±0.03 27 Ho pla e S2-F 0.16±0.03 28 Ho pla e S3-F 0.44±0.08 11 Ho pla e S4-F 0.15±0.02 61 Mic owa e S5-F 0.12±0.02 62 Mic owa e S6-F 0.14±0.02 56 Mic owa e S1-L 2.50±0.13 66 Mic owa e S2-L 2.44±0.13 60 Mic owa e S3-L 0.81±0.11 61 Mic owa e 3. Resul s and discussion The da a ob ained om he adiochemical analysis o Po-210, U-234 and U-238 in all ish samples a e p esen ed on he basis o esh weigh . 3.1. Polonium concen a ion in ish edible ille and li e Figu e 4 p esen s an alpha spec um o polonium iso opes ex- ac ed o a ish sample, showing bo h Po-210 and ace Po- 209 lines. The da a ob ained om he adiochemical analysis o Po-210 in ish samples a e p esen ed in Table I. I shows ha he chemical yields a ained o samples diges ed in ho pla e a e e y low, a ying be ween 11.25% and 28.04%. I was obse ed a yellowish suspension, sugges ing ha his p ocedu e does no ully diges he lipids p esen in he sam- ples, and hen i hinde he p ecipi a ion p ocess o ac inide necessa y a e diges ion. By con as , mic owa e sample di- ges ion p oduced chemical yields abou 60%, because diges- ion o lipids p esen in he ish sample was almos comple e. De e mina ion o polonium concen a ion in sea ish muscle in Sy ia shows concen a ions abou 0.12±0.01 and 0.13±0.042 Bq kg−1we weigh s o he species Spa us au- a a [7]. Resul s ob ained in he p esen wo k o he same species (see Table I a e o he same o de o magni ude as hose epo ed in [7], pa icula ly o hose ob ained by mi- c owa e diges ion p ocedu e. The di e ences be ween al- ues epo ed in he p esen wo k and hose epo ed in [7] may be jus i ied acco ding o eeding pa e ns and concen a- ions o polonium p esen in he aqua ic en i onmen whe e ish li e. Polonium in li e samples showed he highes speci ic ac- i i y alues (see Table I). This is expec ed because his o gan ypically bioaccumula es mo e polonium [18]. FIGURE 4. Alpha spec um o polonium iso opes, in loga i hmic scale, ex ac ed om a ish li e sample. TABLE II. U-238 and U-234 ac i i ies concen a ions, gi en on esh weigh basis, ob ained o di e en ypes o sample ea men . No e: LD deno es below de ec ion limi = 0.004 Bq/kg. SAMPLES U-234 U-238 YIELDS U-234/U238 TREATMENTS (Bq kg−1) (Bq kg−1) (%) S1-F LD LD 38.15 - Ho pla e UTEVA esin S2-F LD LD 25.41 - Ho pla e TPB S3-F LD LD 10.05 - Ho pla e TPB S4-F 0.008±0.002 0.005±0.001 83.96 1.67 Calcina ion UTEVA esin S5-F 0.007±0.001 0.005±0.001 68.62 1.33 Calcina ion TPB S6-F 0.012±0.001 0.008±0.0005 59.73 1.37 Calcina ion TPB S7-F LD LD 79.50 - Calcina ion UTEVA esin S1-B 0.28±0.05 0.74±0.17 10.89 0.38 Calcina ion UTEVA esin S2-B 0.27±0.03 0.57±0.18 3.73 0.47 Calcina ion TPB Re . Mex. Fis. 58 (2012) 224–227 DETERMINATION OF URANIUM AND POLONIUM IN SPARUS AURATA BY ALPHA SPECTROMETRY 227 3.2. U anium concen a ion in ish edible ille and bone. The da a ob ained om he adiochemical analysis o U-234 and U-238 in ish samples a e p esen ed in Table II. I shows ha he chemical yields achie ed o samples diges ed by acid a ack on he ho pla e a e e y low, a ying be ween 10% and 38%. By con as , he calcina ion o he samples be- o e acid a ack o diges ion p oduced chemical yields abou 60%, because i ensu es he diges ion o ma e ial ha could in e e e wi h u anium de e mina ion (see Table II). In he case o bone samples, i was no possible o achie e good measu emen s because calcium ( e y abun- dan in bones) in e e ed wi h he p ecipi a ion o ac inides. The e o e, de eloping p ocedu es o a oid in e e ence by calcium is needed o u anium de e mina ion in bone. 4. Conclusions The bes al e na i e o de e mining u aniumin ille and li e biopsies is he calcina ion o he samples be o e acid a ack o diges ion, ollowed by UTEVA esin ex ac ion. This is a as e p ocedu e, highe chemical yields a e ob ained and i ensu es u anium measu emen in he sample. The bes p oce- du e o polonium de e mina ion was ob ained by mic owa e diges ion. De eloping p ocedu es o a oid in e e ence by calcium o u anium de e mina ion in bone is sugges ed. 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