Аңдатпа
The article presents results of a study of tritium incorporation by vegetable crops with short-term aerial exposure to tritium oxide in laboratory and field conditions . Plants are a key link in the process of tritium migration both in the ecosystem as a whole and in the trophic structure in particular . As a result of photosynthesis , much of tritium is incorporated into the organic matter of plants . In this aspect , the study of tritium incorporation processes and its possible contribution to human radiation exposure from ingested crop products is a relevant task . The aim of the study was to assess tritium incorporation by vegetable crops quantitatively at aerial entry of the radionuclide in the form of tritium oxide . To achieve this goal , laboratory ( in the chamber ) and field ( in the territory of the former Semipalatinsk Test Site ) experiments were conducted with commonly cultivated pepper ( Capsicum annuum ) and eggplant ( Solanum melongena ) that were affected by short-term exposure to tritium oxide vapors . Air was sampled with a tritium collector “OS 1700”. Plant samples for measuring organically bound tritium were prepared using a “ Sample Oxidizer ” unit . Tritium activity in samples was measured with “QUANTULUS 1220”. It was found that tissue free water tritium activity in leaves of Capsicum annuum and Solanum melongena was 1-2 orders of magnitude higher than in stems and fruits . The distribution of tissue free water tritium in both crops with a short-term aerial exposure is described by a decreasing series : “ leaves < stems < fruits ”. The difference between the tissue free water tritium and organically b ound t ritium c oncentration i n p lants f or a ll e xposure v ariants w as a lso 1 -2 o rders o f m agnitude . For o rganically b ound t ritium , n o d istinct r egularity i n t he d istribution o f p lant p arts w as e stablished , w hich i s m ost l ikely d ue t o t he s hort p eriod o f e xposure . By t he t ime t he f ruits w ere f ully r ipe , a s ignificant d ecrease i n t he a ctivity o f t issue f ree w ater t ritium ( t he m ain s ource o f t he f ormation o f o rganically b ound t ritium i n t he p ost-exposure p eriod ) i n a ll p lant p arts w as o bserved . For o rganically b ound t ritium , b oth a n i ncrease a nd a d ecrease i n t he c oncentration w ere n oted i n l eaves a nd s tems , a nd i n r ipe f ruits i t r emained a lmost a t t he s ame l evel a s a t t he e nd o f t he e xposure . The c onversion r ate o f t ritium i n f ield c onditions w as 1 5-30 t imes t han i n t he c hamber . O rganically b ound t ritium t ranslocation i nto e dible p arts o f v egetable c rops i n f ield c onditions w as 2 -4 t imes h igher t han i n t he c hamber , r egardless o f t he t ritium o xide c oncentration i n a ir a nd l eaves . A ccording t o a c onservative a ssessment , t he p ossible c ontribution t o t he d ose o f i nternal e xposure f rom i ngested t ritium p er 1 k g o f v egetables c ontaminated a s a r esult o f s hort – t erm e xposure , b ased o n t he a bsolute a ctivity o f r adionuclide f orms i n C apsicum a nnuum a nd S olanum m elongena f ruits w ill b e : f or t issue f ree w ater t ritium – 0.7 a nd 5.6 n Sv ; f or o rganically b ound t ritium – 1.7 a nd 2.4 n Sv , r espectively . S ince t he l evels o f t ritium o xide i n t he e missions o f n uclear f uel c ycle e nterprises a re m uch l ower c ompared t o e xperimental o nes , t he p ossible c ontribution o f t ritium t o t he d ose o f p ublic i nternal e xposure f rom t he i ngestion w ith c rop p roducts a fter a s hort-term t ritium o xide e xposure w ill b e n egligible .