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RADIOACTIVE CONTAMINATION OF THE OF SOUTHERN AND FINLAND

M. Jasirlska, K. Kozak, JW. Mietelski Institute of Nuclear Physics Radioactive Contamination of Environment Research Laboratory, Krak6w, Radzikowsklego 152

J. Barszcz, J. Greszta Academy of Agriculture Ecology Department, Krak6w, 29 Listopada 46

ABSTRACT Experimental data of caesium and ruthenium radioactivity In chosen parts of forest ecosystems In Finland and Southern Poland are presented and compared. Measurements were performed with a low-background gamma-rays spectrometer with the Ge(LI) detector. The maximum caeslum 137 ativity In litter form Poland is 25 kBq, in that from Finland 39 kBq, In spruce needles It Is 04 kBq (Poland), 09 kBq (Finland) and in fern leaves it Is as high as 15.9 kBq per kg of dry mass In one sample from Poland.

1. INTRODUCTION The Academy of Agriculture In Krak6w was measuring Industrial pollution in forest ecosystems. After the Chernobyl reactor accident these measurements were extended to Include measurements of radioactive contamination. The measurements started In 1987 and were carried out at the Radioactive Contamination of Environment Research Laboratory of the Institute of Nuclear Physics, Krak6w. In this paper measurements of radioactive contamination of forests In Poland and Finland are presented.

2. SAMPLES Samples of the two upper layers of forest soil: litter (AL ) and humus (AI), of two year old needles of spruce (Picea excelsa) and of fern (Anthyrium sp.) leaves were analysed. Samples from Poland were collected in the late summer of 1987 from 19 experimental plots of the Cracow Academy of Agriculture, Department, belonging to the standard net -of areas. The net of these areas covers Southern Poland (see Map.1 and Table 1). an the experimental plots are 60-80 years old. Samples were taken from these plots according to the method of sampling developed for the industrial pollution research. The method was described in detail In paper From two experimental plots we also collected samples (needles or leaves) of beech (Fagus sylvatica), (Pinus sylvestris), fir (Abies alba), elder

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areas of Cracow Academy of Agriculture map. I. Map of eXpe,-3- in forests Of Southern Poland. The are-,,- from which

samples ele CC-lecteI I are mark:ed i black (Sambucus racemosa) and herbs: Senecio sylvaticus and Oxalis acetosella.

TABLE 1. Data about locations In Poland where samples were taken from.

number name height above on Map 1 region of Poland of the lace sea level [ml

7 Western Sudety ts. Petr6wka 1100 21 Eastern Sudety Mts. tnie2nik 1100 23 Eastern Sudety Mts. Biskupla Kopa 850 26 Pog6rze tlAskle Czechow1ce 330 29 Pog6rze Wielickle Kornatka 460 32 Pog6rze Ciq2kowickle Plotrkowice 370 36 Pog6rze Dynowskle Ka6czug-,x 350 38 Beskid 14ski Mts. Czantorla 620 39 Beskid tlAski Mts. Skrzyczne 640 38A Beskid t1qskI Mts. Waplenica 740 Si Beskid tlAskl Mts. Istebna 580 S2 Beskid tlakski Mts. Barania G6ra 1160 54 Beskid WysokI Mts. Babla G6ra 1300 S7 Beskid Sqdecki Mts. Radzlejowa 1200 58 Beskid SqdeckI Mts. Wojkowa 700 60 Beskid Niski Mts. Dukla 550 65 Tatra Mts. Zable 1500 74 Bleszczady Mts. Tarnica 1000 75 Silesian Upland 2yglinek 300

Samples from Finland were collected (using the same method) from 9

temporary experimental areas placed In forests which belong to the Finnish Forest Research Institute. They were collected from spruce forests having 60-80 years old trees. Their localization Is shown In Map. 2 and some

further details are presented In Table 2 Samples were collected In

TABLE 2 Location and numbers of the sample plots In Finnish forests

The places of Forest Height [ml Number of the sampling division above sea sample plots level on Map 2

The Seill Island 27/31 5 1 Vantaa/Ruotsnkyla 75 60 2 Lepinjarwi 98 55 3 Parkano 413 160 4 2 Suonenjoki 41 130 5 Muhos/Pyhakoski/ 331 70 6 Rovanleml/Kivalo/ 132 155 7 Kolarl 38 160 8 Pallasjarvi 69 0 320 9

Explanations: sample forest of the Seill Nature Reserve samples 2 9 - forests research and experiment stations of the Finnish Forest Research Institute.

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Map.2. Lccaticns ir, `nnlsh torests whei, were collec'-ed for this paper. Explanaticns;: I - nuryLei s of tjc_ pjc_,tL life li Tble abbreviations: K. -'ucpic,. C. -Culu. F. cvamemi- T -Turku

e( September and f Irst half of October (plot no 3 of 1988 by one of the authors (J.Barszcz) during his study of the effects of Industrial pollution on forest ecosystems at the Finnish Forest Rsearch Institute, Dpt of In Vantaa. Before measurements all samples were dried at 105 0C and then homogenized.

3.METHOD OF MEASUREMENT Measurements of activity of all samples were done with the standard gamma-rays spectrometer with a Ge(LI) detector. The energy resolution of the 137 spectrometer was 3 keV at 661.6 keV Cs line. The detector was placed In a low-background shield made of cm of lead, 0 2 cm of copper and 0 2 cm of cadmium. Spectra were taken on 1024 channel NTA analyser and then analysed using the IBM XT computer with P.I.M.P. 121 programme. The activity of both caeslum sotopes in the samples was measured by omparison of the given peak area In the sample and In the standard. The typical measurement time was IS hours. The 604.7 keV and 795.7 keV lines were taken Into account to

determine the activity of 134 Cs. The 214 Bi line 609 keV (background) and

134 Cs 604.7 keV were separated numerically. Ruthenium-106 activities were

determined using 511.9 keV and 621.9 keV 106 Rh lines after calibration of

spectrometer efficiency. The contribution of' the background 511 keV

annihilation line In the 511.9 keV line was taken Into account. Samples and

standards were placed In bakers of the same shape having capacity of 150 ccm

and all of them were arranged on the detector In the same way. Samples from

Poland were analysed from April to August 1988 and those from Finland a year later.

4. RESULTS

The results of the measurements are presented In Tables: 3 (samples from

Poland), 4 (samples from Finland) and (additional plant samples from

Poland).

Activities In the samples were decay corrected for 1st August 1987 (samples

from Poland) and Ist October 1988 (samples from Finland) - the conventional dates of sampling.

4.a. Caesium Isotopes

The 137 Cs and 134 Cs activities In layer A lattice) samples from Poland L were placed from (ygline) 300 B/kg 137 Cs) and 95 Bq/kg ( 134 Cs) to

(Wapienica) 2480 Bq/kg 137 Cs) and 930 B/kg (1 3 4Cs - see Table 3 In a deeper layer - A I (humus) contamination level was a few times less. In spruce (Picea excelsa) needles caeslum 137 concentration was between 20

81 TABI 3. Activities of samples collected In forests of Southern Poland

Activity decay corrected for I August 1987

No lattice humus needles fern on (layer A L (layer AI of spruce Hap 137 134 106 -137 134 137 134 137 134 1 Cs Cs Ru Cs I Cs Cs Cs Cs Cs

[Bq/kg of dry mass]

7 680:t3l 215±32 70±110 104±6 47±10 230±17 85:t24 5700±97 1700t59 21 1870±28 690±17 195±40 540±25 165±31 410til 160±15 758ft126 2540±81 23 1460±53 620±55 515±170 1790" 560±16 - - 14140±245 4630igl 26 1530±61 610±62 7251165 8%±1 S 290±10 205±18 76±31 390±17 ISUM 00 29 2420±54 880±46 625±120 1110±25 285±20 295±18 79±37 1040±38 390±43 32 720±61 290±72 650±330 260±9 53±10 58±8 19±15 270±11 90±12 36 626±21 240±2-5 290±125 440±15 88±12 45±4 13±8 99±13 47t19 38 985±43 300±39 41CY-+150 495±15 155±15 355+79 108±51 2710±48 895±3S 39 1475±55 560±55 580±115 1055+73 350±20 120±8 35±17 1120±25 395+93 39A 2480±47 930±36 410±105 620±14 155±12 300±12 98±40 15890+234 5430±12.5 51 665±38 225±43 165±135 395±12 75±11 125±12 49+29 - - 52 1680±61 630±62 1040±185 76S±15 240±13 380±15 92±41 13600±194 4680±94 54 750±21 290±21 510±105 570±28 150±28 340±19 120+74 6750±111 2070±67 57 1810±55 630±52 75±140 87±5 17±5 59±12 54±16 2150±58 580±48 58 800±38 230±35 0±100 - - 47±5 11±6 700±18 235±19 60 620±12 235±12 375±45 210±5 38±4 20±2 6±5 240±14 Sol 1 5 65 660±17 170t14 240±SO 265±14 40±14 200±8 56±28 3100±93 820±77 74 490±44 235±52 775±260 200±7 26±6 32±5 25±10 - - 75 300±26 95±27 465±130 - - 115±18 66±30 TABLE 4 Caesium activity In samples collected In forests of Finland

Activity decay corrected for I October 1988

no. lattice layer A humus - layer A needles of spruce on L Map 137 Cs 134 Cs 137 Cs 134 Cs 137 Cs 2 Bq/kg of dry mass

I 550 ± 16 155 ± is 405 ±10 89 ±9 183± 12 49 ± 15 2 880 ± 43 85 ± 61 343 ±9 72 ±10 54 ± 7 23 ± 9 3 3660 ± 60 970 ± 37 2940 ±42 740 ±22 266± 8 66 ± 9 4 3920 ± 55 1080 ± 54 765 ±16 157 ±12 289± 8 69 ± 12 5 2050 ± 34 570 ± 23 480 ±12 100 ±10 8751 21 200± 22 6 98± 8 16 ± 14 60 ±5 0 ±14 63 ± 4 8 5 7 55± 6 0 ± 14 173 ±14 8 ±5 40 ± 4 0 10 8 193 ± 8 32 ± 9 117 ±7 12 ±7 34 ± 4 10 6 9 98± 6 10 ± 11 119 ±7 0 ±14 52 ± 6 0 10

TABLE S. Caesium activity In plant samples from two experimental plots In Poland (no 39 and 60). Activities were decay corrected for I August 1987

Skrzyczne 39) Dukla (plot 60) 134C. 137 plant 137C. Cs TTi4 Cs

[Bq4/kg d.m.]

Ables alba (fir) 183 7 66 9 26 ± 9 9 ± 8 Pinius slver (pine) 40 ± 5 18 ±11 Fagus syJvatica (beech) 470 15 160 17 71± 8 0 ±10 Sawbuccus raceinosa (elder) 165 9 73 33 90± 9 39 ±28 Senecio sylvaticus 605 t 18 205 22 104±11 32 ±24 Ozalls acetosella 1190 ± 30 430 40 285±37 95 ±65

Bq/kg (Dukla) and 410 Bq/kg (tnletnik) and that of caeslum -134 was from 6 Bq/kg to 160 Bq/kg (Dukla and tnie2nik, respectively). A wide range of caeslum concentration In fern (Athyrium sp.) leaves was observed. The higher activities reach 15.9 kBq/kg 137 Cs and 5. 4 kB(4/kg 1 3 4Cs (Wapienica - see Table 3 The geographical dstribution of contamination with caesium Isotopes In all samples from Poland Is strictly connected with rainfall during the passage of the radioactive cloud 3]. The caeslum activity in samples from Finland Is presented In Table 4. Samples from Southern Finland were generally a few times more contaminated with caesium Isotopes than those from Northern Finland which Is In good agreement with the data of 4 The contamination level In the upper soil layer - A varies from 55 to 3920 Bq/kg d.m. 137 Cs) and f rom 0 to 1080 L Bq/kg d. m. 134 Cs). In the humus layer - A it varies from 60 to 2940

83 Bq/kg d. m. (1 37 Cs) and f rom 0 to 740 Bq/kg d. m. (1 3 4Cs). The caeslum concentrations in both soil layers samples from the low contaminated Northern Finland are nearly equal. In samples from one plot (no 7 -

Rovanlemi) the caesium activity in the humus sample is greater than that In the lattice sample. We have noticed the same In samples from one area from

Poland (no 23 - Biskupla Kopa). In all other samples from Poland and from

Finland the caesium activity of the deeper soil layer samples - A I (humus) was a few times less than that of the upper soil samples (lattice-A L ). Thus we Infer a wide variation of caeslum migration rate in forest soils. The main value of the A /A 137 Cs activity ratio In samples from Finland is equal I L to 0.88 (a = 030), but the analogous ratio for 1 3 4Cs is equal to 048 (o-

0.12). These ratios In samples from Poland were equal to 049 (a- 007) and

0. 34 = ) for 137 Cs and 134 Cs respectively. The A /A activity ratio I L for 1 3 4Cs Is always less than for 1 3 7Cs. Than Is caused by the amount of

1 37 Cs In the humus layer deposited from nuclear weapons tests In the past.

The needles of spruce (Picea excelsa) from Finland were generally more contaminated with caeslum Isotopes than those from Poland. The highest activity observed was 875 Bq/kg d.m. 137 Cs) and 200 Bq/kg d.m. 134 Cs). It

Is interesting that soil samples from this plot (no - Suonenjoki) were not

the most contaminated ones.

4.b. Ruthenium - 106

The only samples In which we were able to determine the activity of

106 Ru were samples of litter layer (A from Poland. The results are L presented In table 3 The geographical distribution of the contamination is different than in the case of contamination with caeslum. The correlation factor between 137 Cs and 106 Ru activities n the A layer Is equal to 0.18. L The highest activity, 1040 Bq/kg, was observed In a sample from plot no 52 -

Barania G6ra. Large errors In the determination of ruthenium activities In all those samples were due to three causes. First, all measurements started over two years after the Chernobyl reactor accident; the ruthenium-106 half-life time is 372 days. Second, the typical mass of a sample was about

30-50 g. Third, 106 Ru determination faces measurement difficulties. We used

two lines of 106 Ru 106 Rh); 511.9 keV (with yield 20.7%( [51 and 621.9 keV

(9.8%). Both of them have low efficiency and the former is additionally

Interfered with by a background 511 keV annihilation line.

S. CONCLUSIONS

The largest contamination by 134 Cs and 137 Cs was found In samples taken

from A L layers in the vicinity of Helsinki. Activity in samples taken at

84 location further to the north decreases In agreement wth data published In

[4]. The concentration of 137 Cs and 134 Cs observed at locations In Southern Poland differ very much. The largest values were observed In the Sudety Mountains, In the Beskid 81aski Mountains and near Krak6w. The are only slightly more contaminated than forests In Northern Italy 16,71. Fern leaves showed significant activity. Dying leaves of fern, needles of spruce and leaves of other trees supply the forest soil with contaminated matter. This leads to a very slow decontamination of this closed bological system. One can expect that forest plants and will have Increased activity for a long time [,91.

6. ACKNOWLEDGEMENTS The authors thank Dr Ewa Ochab for standard preparation and Mr. A.Pletruszewski and Mr. M.Birski of the Central Laboratory of Radiation Protection for standard calibration. A research grant to Dr Barszcz from the Mnistry of Education in Finland Is gratefully acknowledged.. Members of the laboratories In the Dept. of Silviculture at the Finnish Forest Research Institute In Vantaa are thanked for their kind help in collecting samples.

REFERENCES 1. J. Greszta, J. Barszcz, S. Niemtur - Evaluation of damage to mountain forests In Southern Poland; 15 th International Meeting for Specialists In Air Pollution Effects on Forests Ecosystems, Interlaken 28 X. 1988 2. J. W. Metelski - P.I.M.P. - User's Friendly Program for IBM PC Compatibles for Gamma-Rays Analysis from Germanium Detector; Raport IFJ No 1435/S, 1989 /in Polish/ 3. K. Kr6las, M. Kubala, T. Sclq2or - Ground Dposition of Long Lived Gamma Emitters In Poland from the Chernobyl Accident; Raport IFJ No 1348/B, 1986 4. H. Aaltonen et al. - Interim Report on Fallout Stuation In Finland from April 26 to May 4 1986; Raport STIJK-B-VALO 44 1986) S. U. Reus, W. Westmeir - Catalog of Gamma Rays from Radioactive Decay - Parts I and 2 Atomic Data and Nuclear Data Tables vol 29 No I and 2 (1983) 6. E. Baldinl, M.G. Bettoll, 0. Tubertini - Chernobyl Pollution In Forest Blogeocenoses; Radlochimica Acta vol 41 p. 181-190 1987) 7. E. Baldini, M.G. Bettoli, 0. Tubertin - Further Investigations on the Chernobyl Pollution in Forest Blogeocenoses; Radiochimica Acta vol 46 p.143-144 1989) 137 134 S. D.K. Teheran - Determination of Cs and Cs Radioisotopes in Various Mushrooms from Austria One Year after the Chernoby Incident; Journal of Radioanalytical and Nuclear Chemistry Letters 126/6/ p. 401-406 1988) 9. M. Jasiiska, K. Kozak, J.W. Mietelsk - Ceaslum isotopes In mushrooms from Poland (to be published)

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