1978-04-30:.-- Jitiïkoh( S)

' TITLE

Measurement of the natural radiation environment, and' its dependence on various parameters in Austria and assessment of the natural external and-internal .raèiation dose of various population groups ,

FINAL REPORT i?0R 'THE "PEP.IQB

• ..1975-05-bl -•-;-.-1978-04-30:.--

jitiïkoH( s)

E. Pohl

. - University" of -"'Salzburg1 . Chair of Physics Salzburg, Austria

ÉEG)' AGE3CY JS DAÎT •Jtlne

•%•: p LEHRKANZEL FUR PHYSOC UNIVERSITÀTSALZBVRG VORSTAND: UNIK-PROF. OR. ECON POHL AKADEMIESTRASSE26 Se»; A-5020SALZBURG (A USTKIA) ES TELEFON(U6222)44SII-37l'4S6 SALZBURG. AM 1978-06-02

Final Report

a) (i) Contract Number: 1493/RB; 1493/Rl/RB; 1493/R2/RB

(ii) Title of project;

Measurement of the natural radiation environment and its dependence on various parameters in Austria, and assessment of the natural external and internal radiation dose of various population groups.

(iii) Institute where research is being carried out:

Institute of Physics (Lehrkanzel fiir Physik) of the University of Salzburg, Akademiestrafie 26, A-5020 Salzburg, Austria

(iv) Chief scientific investigator:

Univ.-Prof. Dr. Egon Pohl

(v) Time period covered:

Research Contract 1493/RB: 1 May, 1974 till 30 April, 1975 Renewal Res. Contr. 1493/Rl/RB: 1 May, 1975 till 30 April, 1976 Renewal Res. Contr. 1493/R2/RB: 1 May, 1976 till 30 April, 1977 For the final report additional measurements and calculations were carried out till 30 April, 1978. ^^

b) Description of research carried out: 9m Mi

Inhaled radon and its decay products cause an important part of the human natural radiation burden in a normal environment. Measurements of these nuclides are, however, complicated by the. fact that outdoors as well as if indoors there are not only large local variations due to differences in geological subsoil and in construction materials of houses but also temporal fluctuations due to the influence of meteorological parameters. Therefore in our investigations main emphasis was laid on the determination of statistically significant mean annual values for the single, nuclide concentrations. In order to obtain mean annual nuclide concentrations with a limited number of measurements a suitable sampling method was developed which consists of the combination of grab-sampling with long-term series of measurements (2).

The inhalation of radon and its decay products results in an inhbmogeneous dose distribution within the body and causes, therefore, different organ doses. For this reason we calculated the specific mean annual doses for the sa most important organs and tissues for each testperson. At the sites referring II. to the respective personal life pattern significant annual mean values of the 1" natural radionuclides in the air and the external gamma-radiation were determined as a basis for these dose calculations.

Moreover frequency distributions of several specific organ doses withia various population groups were investigated using demoscopical methods which means to select testpersons as representatives for thefahole population.

Hitherto the radiation burden was entirely investigated for the adult "Reference Man". In order to get more satisfying information we carried out detailed calculations to elucidate the respective conditions with children and adolescents (13). I Sites and kinds of investigations

Measurements of the natural air activity indoors as well as outdoors and the external gamma-radiation were carried out in the following sites:

1. In Salzburg Town (150 000 inhabitants) as an example of a typical Central European town, situated on a geological subsoil with low natural radioactivity. In this location a demoscopical method was used selecting I) •j-:'?r-&Jii£~S'2'!Ti " m testpersons as representatives of the whole population. On the. base of more than 8000 measurements during four years statistically significant W dose distribution histograms for the most important organs could be established. pf 2. At Badgastein ( 5 500 inhabitants), a radon spa with an elevated radioactive environment, mainly characterized by an increased content 222 * * • - ' * of Bn and daughters in the atmosphere indoors and outdoors. Several thousand measurements were carried out at different seasons. 3. In the Gastein Valley and Mallnitz in order to study the natural radioactivity in dependence of the geological subsoil along the whole Gastein Valley. This valley reaches from south to north extending from the "Hone Tauern" ( a central montain chain and divide of the Eastern Alps) l-f with BSckstein as its highest situated village and Lend as its lowest point, the junction with the Salzach Valley, running east-west.

At Mallnitz, a village situated on the southern side of the Tauern chain at the same sea-level as Bockstein, which was taken as an example of comparison. .

4. At several other places situated at a line crossing the Alps from south to north, a pilot study was carried out in Carinthia (Spittal a. D.) and in the Country of Salzburg (Schwarzach, Forstau, Hallein, Kuchl, Grodig and Voggenberg/Bergheim).

'• & 5. In 15 different mines of the countries of Salzburg and Upper-Austria, to investigate the radiation burden of mainly non-uranium miners.

c) Results obtained . fe- The method of the calculation of the radiation burden due to inhalation rn of the natural radionuclides was published previously (2).

The results at the sites given above are these:

1. Salzburg Town:

These investigations were reported at four international symposia and can be seen from the corresponding proceedings (1,2,3,14). The most 'TA.

detailed of them is no. 14 which is part of this final report. Besides . there are two papers in German (4, II). The most important results of this study are: mi' a. The radon content of, théair ^sfhigtier hotionly outdoors but al.so indoorsthan^uàualïy;: assumed." We found.indoors that ^ih'11,6.3.% of -1'.". the rooms: investigated; the; annual mean value was and in 2.3 % highei than 3 j?CÏ/ï. ^

b. The dose-calculations, for the 722 testpersons demonstrated, that only those organs and tissues show wide'dose ranges which are remarkably 1 "' " • 222' ' ' '"'i '" ' ' " " '" ' influenced by the inhaled to decay products. The ratio of the maximum to the minimum is only 1.7 for the gonads and bone marrow, rises up to about 5 for the kidneys, to 35 for-the alveolar tissue and even •38 to 92 for the bronchial epithelium.

2. Badgastein:

.This is a spa characterized by thermal.,springs, in the center of the town, supplying about 5 million liters of hot water per day with a mean radon content of 40 nCi/1. About 1 million liters of it are delivered to

.?•'.•;•• . Bad Hofgastein, a 7 km distant spa. In each of the .two.places the.thermal water is kept in large reservoirs from which it is conveyed to about 130 hotels and spa houses. . At the sources of the springs and from the reservoirs most of the radon-emanates already into the air of the environment, but also during.the baths themselves (the.radon content of the water in the bathtubs is 10 to 13 and 15 to 20 nCi/1 in Badgastein and Bad Hof- it; gastein respectively^ Even the sewages exhalate radon thus contributing to the air activity. Thus the radon of the water passes almost entirely into the air outdoors and. indoors, which amounts to about 58 Ci per year for Badgastein and 15 Ci per year for Bad Hofgastein. Therefore and because of the narrow building zones the:mean radon contents, in the room and in the open air are higher at Badgastein, to which our dose assessments mainly refer. Tab. 1 gives the mean contents of Rn and its daughters at various indoor and •it outdoor sites of Badgastein, being the basis for our dose calculations. The individual doses turned out to be very different according to the different air activities in the various sleeping-, living- and working-rooms as well ti as to the different living habits (mean stay at the various pices and living activities there). We also calculated the radiation burden of many persons for investigations of biological effects, mainly chromosome aberrations (15-21). For this report, however, we defined two model persons to give a general example for the radiation dose at Badgastein. Modelperson 1 corresponds, to a bath attendant living and working in the center of the town (zone 1 ). Modelperson 2 is a person living and working in the center but not belonging to the therapeutic personneli Table 2 gives the annual doses of the basal cells of the segmentai and subsegmental bronchials, as the organ with the highest burden. Xhese doses were calculated according the most recent method developed by Hofmann et al. (13).

3. Gastein Valley and Mallnitz: 222 The mean annual values of the Rn-concentration and of the gamma- radiation indoors and outdoors are given in Table 3. The radon contents of the air at Klatmnstein, Dorfgastein, Bad Hofgastein, Bockstein and Mallnitz are significantly higher than that in Salzburg Town and of the same order of magnitude as zone II of Badgastein (Table 2). 4. Other villages:

We only carried out a pilot study at these places, therefore the mean values given in Table 4 are not of/high significance due to the seasonal variations of the air activities. . . 222 It is remarkable that at Forstau the mean value of the Rn content in the air is not much higher than the other mean values in spite of mining small quantities of low-concentratéd uranium ores there.

5. Selected mines in Salzburg Country and Upper-Austria:

I'v Host miners receive a higher radiation burden due to external gamma- radiation from the surrounding rocks as well as from the increased f: 222 concentrations of natural radionuclides in the air, especially of Rn and its short-lived daughters. For dose calculations it is necessary to determine statistically significant mean values of the nuclide concentrations and gamma radiation and the amount of time spent at the respective

In our previous publications we used the estimation of Jacobi (1964), being about twice as high. 6 ;ï

areas of employment. Due to large local and temporal variations of the atmospheric radioactivity, influenced by varying ventilation conditions and meteorological parameters, numerous single measurements or special integrated measuring techniques are necessary.

: In a pilot study 230 sites were selected in 15 underground- and open- cast mines with about 2000 employees in the countries of Salzburg and Upper-Austria. The types of mines were: salt, quartz, gypsum, clay, kaolin, coal and uranium mines. Results of these measurements are given in Figure 1 to 4. They show that the rates of the four activities investigated, namely 090 91A ' 219 gamma-radiation, Rn, RaB ( Pb) and ThB ( Pb), are found to be different in the various mines. Comparing mines extracting various minerals one must take into consideration the different working conditions, i. e. ventilation, length 222 and volume of the mine. The relatively low levels of Rn, RaB and ThB in the uranium mine investigated are caused by the high ventilations. In the copper mine the air activity is relatively high, because there are some patches of uranium ore. These, however, are not mined and therefore the ventilation is kept low there. . ,; \ It is remarkable that the ThB contents of the air in the coal, kaolin and salt mines investigated are relatively high, none the less of a low 222 . Rn concentration. A preliminary result of our measurements is given in paper no. 5. A detailed paper is in preparation.

d) Conclusions;

Our work demonstrates great local differences of some components of the natural radiation sources even within relatively small areas like a town or a village. This holds especially for the radionuclides in the air which show moreover great temporal differences at one and the same site. These fluctuating components have mainly to be considered for calculating the radiation burden of individuals or of smaller or bigger population groups.

Radiation doses have to be calculated separately for the various organs and tissues as the external irradiation and much more the incorporation of radionuclides cause an inhomogeneous dose distribution within the organism. The dose estimations due to inhalation of radionuclides hitherto given in the literature only refer to the adult "Reference Man" and are therefore not sufficient as our dose calculations demonstrate a dependency on age, n r, • sex and weight. The most striking result is that at the age of 6 there is twice the dose of the respiratory tract than in an adult (10, 13).

Jl ; The calculation of thé radiation, burden also.;requiresi, the-consideration

of the actual physical^ activity of;..the "person^investigated.:àt; thé; various living sites as the doses due ito inhalation 9f;the decay products bf' . En ^ and ?-Rn areiprbpbrtibnâl to the)respiratory minute .volume; Our. investigations te have shown that even in a town with a low radioactive environment high dose values can occur due to inhalation of radon and decay products. The tissue with the highest natural radiation burden is the basal cells layer of the epithelium of the segmentai and subsegmental bronchial s (4th to 9th generation in the lung model of Weibel). These cells are the critical ones for the -induction of lung cancer. It is remarkable that about 64 % of the population investigated by us receive more than 0.5 rem/yr, 25 % more than 1.5 rem/yr É and 1.3 % more than 3 rem/yrI (Assuming a Quality Factor of 10 for alpha- radiation). It might be possible that these doses act synergistically in con- V nection with other car cenogenous factors, especially cigarette smoking.

From our studies can be seen furthermore that the estimation of mean values alone is not sufficient in order to consider all the aspects of the radiation burden of a population.

The different air activities of the living- and working-rooms are caused entirely by differences in building materials and in the construction of the houses. The materials of the houses cover a wide range from prefabricated concrete parts to all kinds of bricks and natural stone. The different . architectural styles of the buildings inhabited comprise modern multistoreyed buildings as well as medieval houses. This is not only typical for the town of Salzburg, but also for many other Central European cities,: which are therefore supposed to supply similar results. In areas on subsoil with higher natural radioactivity the dose values will even be higher.

Our measurements in various places of Austria have shown that their mean ë.-'-; values of the air activity and the external gamma radiation differ less from one to another than those within one and the same village or town, except areas with elevated radioactive environment as for example Badgastein. fc^ ' ; •'/'" -, IK'^V'tV^

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Tab. 2 Basis and results of dose calculation • i for 2- "model persons" in Badgastein - • |

Model person I (man, light work) Bath attendant employed and living in the centre of the village

H Annual mean values for Annual stay Site 222Rn

bathrooms 90 0.4 400 rooms connected to thermal baths 46 0.4 2000 living rooms of zone I 10 0.6 2200 sleeping rooms of zone I 10 0.6 2900 living rooms of zone II 3 0.6 200 open air of zone I 2.6 0.5 360 open air of zone II 0.8 0.5 360 outside the village 0.4 0.6 340

Working level month/year: 5.9 Calculated annual dose of the basal cells of segmentai and subsegmental bronchies: 17.9 rem/year

Model person 2 (man, light work) Employed (office work) and living in the centre of the village

Annual mean values for Annual stay 222_ Site Tin (pCi/1) RaB/Rn in hours

living- and working rooms of zone II 10 0.6 4100 sleeping rooms of zone I 10 0.6 2900 living'rooms of zone II 3 0.6 240 open air of zone I 2.6 0.5 360 open air of zone II 0.8 0.5 360 outside the village 0.4 0.6 800

. Working level month/year: 2.8 Calculated annual dose of the basal cells of segmentai and subsegmental yt bronchi^s: 7.8 rem/year IP;,

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SS-: Tab. 3 Results of measurements of the natural radioactivity indoors and outdoors in the Badgastein region including Mallnitz (Carinthia).

222Rn-concentration (pCi/1)

*..';:•

indoors outdqors Site Min Mean Max - Min - Mean Max

Lend/S <0.05 0.6 2.9 <0.05 0-3 2.1 Klammstein/S <0.05 3.0 12.3 <0.05 0.6 1.3 Dorfgastein <0.05 0.9 6.4 <0.05 0.2 3.3 Bad Hofgastein/S <0.05 1.1 3.2 <0.05 0.4 2.2 I;; Bockstein/S <0.05 4.3 18,3 <0.05 0.6 2.4 Mallnitz/C <0.05 1.3 9.8 <0.05 0.4 1.3

Gamma-radiation (without cosmic rays) Çurd/h)

indoors outdoors Site Min Mean Max Min Mean Max Lend/S 4.7 8.1 15.3 2.5 5.0 13.3 Klammstein/S 6.3 8.0 10.5 2.8 3.4 4.6 Dorfgastein/S 2.0 7.9 16.1 2.6 5.9 8.0 Bad Hofgastein/S 1.8 8.6 17.8 3.0 4.9 8.3 I? S Bockstein/S 5.0 14.3 31.8 4.3 11.9 14.8 Mallnitz/C 2.6 11.3 19.3 3.4 ' 8.1 13.3

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Tab. 4 Results of measurements of the natural radioactivity indoors and outdoors in Salzburg country and Carinthia without the Badgastein region

222Rn-concentrâtion (pCi/1)

~ ' ' ". -"':"'•--- Indoors outdoors Site "••»- Min Mean Max Min Mean Max Voggenberg/S <0.05 0.6 1.4 <. 0.05 0.3 0.6 GrBdig/S 0.1 0.3 0.5 < 0.05 0.4 0.8 Kuchl/s.' ' 0;08 0.5 0.9 < 0.05 0.4 0.8; Halléin/S 0.06 0.1 0.2- <0.05 0.4 0.9 F6rstau/S <0.05 Î.3 7.9 <0.05 0.2 0.5 Scbwarzacb/S <0.05; 0.6 5.5 : <0.05 0.2 1.1 Spittal a. D./C<0.05 0.7 4.1 <0.05 0.3 0.7

Gamma-radiation (without cosmic rays) (urd/h)

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Voggenberg/S 5.3 6.6 6.9 2.6 4.4 •;.• 6.2 A 6r8dig/S 4.8 5.9 7.2 4.1 4.8 •;:6.5-.-- "'A Kuchl/S 5.2 6.2 7.7 4,3 5.7 6.7 Hallein/S 4-1 4.9 5'! 2.4 3.5 4V6 Forstau/S 5.7 6.7 8.1 4.8 5.7 6.9 Schwarzach/S 3.6 7.1 15.3 3.4 4.6 6.5 if Spittal a. D./C 5.0 ,8.8 14.0 6.9 8.6 11.5 %I 2

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f • e) Papers published on work done under the contract;

1. Steinhausler, F., Hofmann, W. and Pohl, E.: Urban natural radioactivity in Salzburg, Austria, and its resulting dose for various organs in different groups of inhabitants. Proc. 3rd Europ. Congr. Internat. Had. Protect. Ass., Amsterdam, 1975:G4.

2. Pohl, E., Steinhausler, F., Hofmann, W. and Pohl-Ruling, J.; Methodology of measurements and statistical evaluation of radiation burden to various population groups from all internal and external natural. sources. Biological and Environmental Effects of Low-Level Radiation, IAEA, Chicago, 1976, Vol. 11:305-315.

3. . Steinhausler, F., Hofmann, W., Pohl, E. and Pohl-Ruling, J.; Natural ;* radioactivity in an urban environment and the resulting dose frequency distribution of the population for the most important organs. Natural Radioactivity in Man's Environment. 10th Midyear Topical Symposium, Saratoga Springs, New York, 1976.

4. Pohl, E., Steinhausler, F., Hofmann, W. and Pohl-Ruling, J.; Methodisches zur Messung und Berechnung der Strahlenexposition des Menschen durch natiirliche Quellen ionisierender Strahlung am Beispiel einer Uhtersuchung an der BevSlkerung der Stadt Salzburg. Jahrestagung des 5sterr. Strahlen- schutzverbandes, Wien, 1976:19-39. I 5. Steinhausler, F., Hofmann, W., Pohl, E. and Pohl-Ruling, J.: Untersuchungen tiber die Strahlenbelastung der Arbeiter in Bergwerken Salzburgs und Ober- osterreichs. Jahrestagung des 6sterr. Strahlenscbutzverbandes, Wien, 1976:44-67.

6. Hofmann, W. und Steinhausler, F. : Die Strahlenbelastung des Atemtraktes bei der Inhalation naturlich radioaktiver Nuklide. Ber. nat.-med. Ver. Salz- burg 2 (1976):7-25.

7. Hofmann, W., Steinhausler, F. and Daschil, F. : LDMO - a simulation study of age dependent lung dosimetry for inhaled radioactivity. DECUS Europe Symposium, London, 1977:315-320.

8. Hofmann, W.: Modell zur Simulation des Verhaltens naturlich radioaktiver Nuklide in der Luft von Wohn- und Arbèitsraumen mit Hilfe eines Hybrid- rechners. Interface 8(1977):19-24.

9. Hofmann, ff., Steinhausler, F. und Hummer, H. : Modell zur Simulation der Altersabhangigkeit der Sosis im Atemtrakt bei der Inhalation naturlich radioaktiver Nuklide. Teil 1. Interface 9(1977):37-46.

10. Hofmann, W. and Steinhausler, F.: Dose calculations for infants and youths due to the inhalation of radon and its decay products in the normal environment. Proc. 4th Internat. Congr. Internat. Rad. Protect. Ass., Paris, 1977:497-500. 11. Pohl, E.; Steinhâusler, F. und Hofmaan, W. : Die natiirliche Strahlen- exposîtion der Bevolkerung der Stadt Salzburg - Ergebnisse einer vier- jahrigen Untersuchung des Institutes fur Physik fur Bio- und Geowissen- scbaften. Jahrbuch 1976/77 der Universitât Salzburg.

12. Hofmanh, W. : Miilticompartment-models for the simulation of the indoor natural radiation environment and the resulting dose distribution in man. Froc. IMA.CS Symp. "Simulation of Control Systems", Vienna 1978.

J3. Hofmann, W., Steinhâusler, F. and Pohl, E.t Age-, sex- and weight dependent dose distribution pattern for human pattern for human organs and tissues due to inhalation of natural radioactive nuclides. Proc. nat. Rad. Env. Ill, Houston, 1978. -

14. Steinhâusler, F., Hofmann, W., Pohl, E. and Pohl-Ruling, J.: Local and temporal distribution pattern of radon and daughters in an urban en- vironemnt and determination of organ dose frequency distributions with demoscopical methods. Proc. Nat. Rad. Eny, III, Houston, 1978. f) Other relevant literature references;

15. Pohl-Ruling. J., Pohl, E., Fischer, P. and Sahu. N. K.; Dose estimation for workers exposed to Rn 222 and an investigation of chromosome aberrations in their peripheral blood lymphocytes. > Health Physics 19(1970): 154.

16. Fischer, P.. Pohl-Rulihg, J. and Pohl, E. : Chromosome studies on persons exposed to increased levels of radon * in the : environment. 4th Int. Congress of Human Genetics, Paris, 1971, No. 233.

17. Pohl-Ruling, J., Fischer. P. and Pohl, K.: Dependence between internal dose due to the inhalation of Rn 222 and its daughters on chromosomal aberration in peripheral blood lymphocytes. Proc. 2nd Europ. Congr. Internat. Rad. Protect. Ass., Budapest, 1973: 125-128.

18. Pohl-Biiling. J.; Chromosome aberrations in the peripheral blood lymphocytes of people living or working in areas of higher atmospheric concentration of natural radon 222 and its daughters in Bad- gastein, Austria. Techn. Rep. 154, IAEA Res. Contr. 14 Ann. Rep. IAEA, Vienna, 1974 Res. Contr. 791: 150-152.

19. Pohl-Ruling. J.. Fischer. P. and Pohl, E.: Chromosome aberrations in peripheral blood lymphocytes dependent on various dose levels of natural radioactivity, Biological and Environmental Effects of Low- Level Radiation, IAEA, Chicago, 1976, Vol. II: 317-324.

20. Pohl-Ruling^ J., Fischer. P. and Pohl; E:: The low-level shape of dose response for chromosome aberrations. Proc. Int. Symp. of Late Biol. Effects of Ionizing Radiation, IAEA, Vienna,1978.

21. Pohl-Ruling, J., Fischer. P. and Altmann. H.: Correlation between chromosome aberrations and DNA repair capacity in the peripheral blood lymphocytes of workers due to inhalation of radon and daughters. Proc. Int. Meeting on DNA Rapair and Late Effects, Tel. Aviv, 1978.