Contamination of some important kinds of plants by fission products

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  • Journal of Radioanalytical and Nuclear Chemistry, Articles, Vol. 131, No. 2 (1989} 311-317

    CONTAMINATION OF SOME IMPORTANT KINDS OF PLANTS BY FISSION PRODUCTS

    N. AJDA~IC, M. MARTIC

    Boris Kidri~ Institute of Nuclear Sciences, Vin~a, P.O. Box 522, 11000 Beograd (Yugoslavia)

    (Received November 14, 1988)

    Quantitative data for some of the radionuclides, most important because of their intensity and radiotoxicity, present in the biosphere after the Chernobyl accident are given for a selected number among numerous plant and food samples analyzed before and after the accident.

    I n t roduct ion

    Starting from increasing contamination, detected on the basis of muttidisciplinary studies in the case of hazardous radiation, it is important that preventive measures are taken on time and with the aim of protecting drinking water, plants, domestic animals and human population. Even if they cannot eliminate evident danger, pro- tective measures ought to be so organized as to reduce to the greatest possible extent the consequences of the accident. In order to achieve this, it is necessary to:

    - acquire on time sufficient and reliable information on the extent of potential danger,

    - mobilize all available social forces with the aim of self-protection in accordance with the established REAL danger, and

    - react with full responsibility to all signs of existing danger. No efficient protection could possibly be achieved if any of the above conditions

    are not fulfilled,, which would also mean negligence in the obligations towards the population.

    To provide immediate and reliable information about the existing danger is appa- rently the first step in a series of activities expected in any civilized society.

    Although we did provide full information already in the first days of May, 1986,1 by this work we wish to contribute to elucidation of true radiation contamination of biosphere and thus also to providing the basis for a scientific, multidisciplinary approach to the problem and calculation of the doses of population exposure to ionizing radia- tion in order to anticipate possible somatic and genetic consequences of the Chernobyl accident.

    Elsevier Sequoia S. A., Lausanne A kaddmiai Kiad6, Budapest

  • N. AJDACIC, M. MARTIC: CONTAMINATION OF SOME IMPORTANT KINDS

    Results and discussion

    In the case of primary contamination of the biosphere (nuclear explosions, acci-

    dents in nuclear installations etc;), air and fall-out are predominan t transporters of radioactive materials.

    It is clear, therefore, that fully responsible introduction of special protection measures must be based on exact data on contamination of fall-out, particularly when primary contamination lasts longer than several days or weeks and efficient protec,

    tion against contamination by breathing is especially difficult. For this reason in choosing the'samples analyzed and discussed in the present work we had in mind the fact that the sourCes of most dangerous Contamination should be pointed out and faced openly. Precipitations as a general source of all kinds of contamination are the subject of a separate 'study, 2 whereas in the present work we analyze cattle fodder

    Table 1. Activity (kBq/kg) of several important radionuclides (fission products) present

    Kind of sample Place and time of sampling

    Activity, kBCl/kg

    144Ce 13~Te

    Meadow grass (fresh sample)

    Lucerne - flower (dry sample) mown before May 1, 1986

    Lucerne (fresh sample)

    Lucerne - flower (dry sample)

    Lucerne - flower (dry sample)

    Lucerne (fresh sample)

    LemOn balm (fresh sample)

    Camomile (fresh sample)

    'Parsley (fresh sample)

    Parsley (dry sample)

    Meadow grass (fresh sample)

    Vin~a, 0.3-+0.1 5.77-+0.05 May 5, 1986.

    Vr~ac, (13-+11)- 10 -3 (19-+3). 10 -3 May 3, 1986.

    Vr~ac, May 8, 1986. 1.0-+0.3 3.35-+0.07

    Vr~ae, May 8, 1986. 3.2-+0.7 13.0 -+0.2

    Stari Tami], May 7, 1986. 5.3-+0.8 23.7 +-0.4

    Stari Tami~, May 8, 1986. 0.8+_0.3 4.23+_0.08

    Pan~evo, (surroundings) 2 .7 -+0.3 3.90+_0.09 May 7, 1986.

    Novo Mile~evo, 3.4 +_0.2 May 6, 1986.

    Pan~evo, (surroundings) 1.4+-0.3 5.3 +_0.1 May 6, 1986.

    Pan~evo, (surroundings) < 4 9 10-4 < 7 9 10-s from 1985.

    Vin~a, June 20, 1985. < 1 9 10 -s < 2 9 10 -6

    312

  • N. AJDACIC, M. MARTIC: CONTAMINATION OF SOME IMPORTANT KINDS

    and food of animal origin, since milk and meat are direct means of introduction o f

    radiocontaminants in the human organism. We aIso discuss contamination o f several

    kinds Of medicinal herbs for the reasons to be seen later. We should like to point

    out here that the rain content recorded on a wider territory in the surroundings of

    our control station on May I, 1986. was enormous: 61.5 mm of the total of 63.5/24

    hours was recorded between 17 and 19 hours only~ High contamination of the ground,

    surface waters and all kinds of plants ,can~doubtless be explained by these results.

    Extremely high contamination of the biosphere over a very large territory in Yugos-

    lavia, apparently was due to high precipitation, as can also be seen from the food and

    cattle fodder contamination data reported by other authors. 3

    Among many analyzed plant and products, samples we have chosen for presenta-

    tion only the results obtained for some most important kinds: meadow grass which is

    used as fodder and which, on one side, was collected on a territory exposed to high

    in plant samples on the territory of Yugoslavia after the accident of the Chernobyl Nuclear Power Plant

    Activity, kBq/kg

    ~s~j ~O3Ru ~O6Ru ~a4Cs ~37Cs ~4OBa ' 14OLa

    3.95-+0.05 6.02-+0.06 3.0-+0.2 1.62-+0.04 2.93-+0.05 4.87-+0.07

    (38-+3)" 10 -3 (36_+4) 9 10 -~ < 2 9 10 -4 (6_+3) 9 10 -3 (13-+4)" 10 -~ (20+-4) 9 10 -3

    11.1 -+0.1 7.1 -+0.1 3.5-+0.5 1.72-+0.07 3.3 -+0.1 6.6 -+0,2

    46.0 -+0.5 28.0 -+0.4 11 -+1 8.0 -+0.3 14.8 -+0.3 28.0 +-0,6

    54.2 -+0.8 43.7 -+0.7 -11 -+2 15.5 -+0.4 30.2 -+0,6 53 -+1

    13.6 -+0.2 7.7 -+0.1 3.3-+0.5 2.7 -+0.1 5.1 8.8 -+0.2

    16.5 -+0.2 8.4 -+0.2 2.8-+0.5 3.3 -+0.1 6.4 -+0.2 7.8 -+0.2

    14.9 +0.4 4.3 -+0.2 1.4-+0.5 1.0 -+0.1 1.6 _+0.2 2.0 _+0.2

    17.1 -+0.3 11.2 -+0.3 4.1-+0.7 3.1 -+0.2 5.7 -+0.2 7.9 -+0.3

    < 1 9 10 -4 < 2 9 10 -4 ' ( 6 9 10 -3 (29-+4) 9 10 -a (88_+6) 9 10 -a < 4 9 10 -4

    < 4 9 10 -6 (5_+2) 9 i0 -3 < 5 - 10 -s (8+-7) 9 10 -5 (4+-1) 9 10 -5 < 1 9 10 -s

    313

  • N. AJDACIC, M. MARTIC: CONTAMINATION OF SOME IMPORTANT KINDS

    precipitation and on the other hand was regularly controlled before and after the Chernobyl accident; 4 lucerne, planted on very large surfaces, is an especially impor- tant analyzed material since it causes direct introduction of radionuclides in the ani- mals' organisms and, through meat, milk and their products, also in the human organ- ism. Among medicinal herbs we have analized those which are considered as most important for use in pharmaceutical and cosmetics industry such as: camomile, lemon balm and parsley, which are basic raw materials for numerous products.

    Numerical data are given in Table 1. The data presented in Table 2 are only a part of the results obtained for milk, milk products and baby food samples.l' s All gamma- -spectrometric measurements were performed by using a HP(Ge) semiconductor de. rector and ND-2400 analyzer. Due to high complexity of the spectra obtained, data were calculated by the TPA method.

    Numerous data accumulated during many years of biosphere radioactivity control as well as by gamma-spectrometric analyses of samples collected after the Chernobyl accident (of which only a small part is presented here), support some definite con- elusions.

    Contamination levels of the same kinds of plants detected on sampling locations at large mutual distances are evidently approximately equal and extremely high! (Except for some minor regions, the results of fruit and vegetable analyses show high contamination of the whole territory of the Republic of Serbia, which has also been proved by the surface waters analysis.) 1 Contamination levels in particular regions are directly proportional to precipitation contents in the first days of May, 1986.

    Variation factors of plant contamination by different radionuclides in May 1986, as compared to the period preceeding contamination, are of the order of n 9 104 to n ' 106 for meadow grass. For medicinal herb~ these factors vary within a range of values lower by one order of magnitude, pointing to higher radionuclide accumulation in these species even before the Chemobyl accident, which is also proved by the exceptionally high contamination detected in May 1986.

    Proper and timely announcing of the approaching danger and well organized crop collecting, for example, can contribute to a large extent to adequate food and fodder protection. In this particular case these conclusions are proved by the results of our analysis of lucerne samples ~own in the same region, but mown and collected before and after maximum contamination (Table 1).

    As concerns milk, milk products and meat contamination the results reported here suggest, it is necessary in estimation of radiation risks to pay careful attention to the presence of all more or less radiotoxic radionuclides detected in the biosphere. This is especially valid for the so-called "critical" part of the population: children, pregnant women and nursing mothers, for whom the presence of 90 Sr in food should in no

    314

  • N. AJDACIC, M. MARTIC: CONTAMINATION OF SOME IMPORTANT KINDS

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    315

  • N. AJDACIC, M. MARTIC: CONTAMINATION OF SOME IMPORTANT KINDS

    Table 3 Activity (Bq/1) of 131 I, ~ 3, Cs, t z 7 Cs and 9 o Sr in the samples of nursing mothers' milk

    Place and time 1311 la4Cs lSTCs 9oSr Kind of sample of sampling

    Nursing mother's milk Belgrade, February 17, b.d.l.* 4.4_+0.9 18+-2 < 0.06 (mother A. Lj, fed 1987 on controlled food)

    Nursing mother's milk, composite sample (from several hospi- talized donors

    Institute for prematurely born children, Belgrade (mothers from S. R. Serbia and S. R. Bosnia and Hercegovina), February 18, 1987

    0.2_+0.2 10 -+2 24-+2 2.2-+0.2

    *Below detection limit.

    case be neglected, 6 but still no limiting values were determined long after the Chernobyl accident.

    "Risk limits" problems should be discussed thoroughly and with full responsi- bility, paying special attention to possible hazards as the consequence of their irre-

    sponsible and arbitrary alteration (Table 3).

    Conclusion

    ~fumerous activities carried out with great effort all over Europe to prevent hazards due to the nuclear accident in Chernobyl provided reliable and fully responsible infor- mation on the level of radioactive contamination of the living environment immediately

    after it has been detected only in few cases. Unfortunately, there were even opposite

    opinions. Nevertheless, there is no doubt that in the future no one acting with honourable

    human aims could possibly fulfill their duty in defending achievements of civiliza-

    tion without: - taking into account radiation of all relevant radionuclides in the spectrum,

    identified and quantitatively determined in samples from biosphere and especially

    of precipitation several months after the Chernobyl accident if they try to estimate

    reliably the radioactivity of the biosphere; - providing public information timely and openly on the exact degree of contam-

    ination and danger, which is an absolute prerequisite for self-protection of the

    population;

    316

  • N. AJDACIC, M. MARTIC: CONTAMINATION OF SOME IMPORTANT KINDS

    - maintaining recommended protection measures during a period of time suffi-

    ciently long for complete safety;

    - preventing with all mights international exchange of contaminated food, and last but not least,

    - treating with full responsibility and care for future generations the problems of

    determining new limits of tolerant radioactive biosphere contaminations.

    Only in this way could mankind calmly accept unavoidable development of nuclear power plants.

    References

    1. N. AJDA~IC, M. MARTIC, Kontaminacija ~ivotne sredine u na~oj zemlji, kao posledica ~ernobiljske katastrofe, u periodu od 30.04. do 01.07. 1986., godine, prema merenjima u Grupi za istra~ivanje biosfere IBK - Vinga (in Serbocroatian). Final Report IBK, Vin~a - Internal publ., Dec. 1986.

    2. N. AJDA~IC, M. MARTIC, J. Radioanal. Nucl. Chem., 128 (1988) 309. 3. P. MARKOVI~ et al., Current problems and concerns in the field of radiation protection,

    Proc. 14th Regional Congress of IRPA' Kupari-Dubrovnik, Yugoslavia, Sept. 29.-Okt. 2, 1987. 4. N. AJDA~IC, M. MARTIC, Contents of ~ 3 ~ Cs and 9 o Sr in the samples from the surroundings of

    nuclear plant, Proc. l l th Regional Congress of IRPA, Vol. 2, Vienna, Sept. 20-24, (1983) p. 81.

    5. N. AJDA~I(~, M. MARTIC, Rezultati gamaspektrometrijske analize mleka u prahu i de~ije hrane (in Serbocroatian). Izve~taj za Komitet za tad, zdravlje i Socijalnu politiku SFRJ, April 1987., Int. publ. IBK, 1987.

    6. B. C. BORISOV, Investigation of the weight parameters of human skeleton: its use for some radiohiological calculations. Proc. 3rd Intern. Summer School on Radiation Protection, Herceg Novi, Yugoslavia, Sept., 1976, Vol. 1, p. 237.

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