Consequences of the reactor accident in chernobyl in the federal republic of Germany: Environmental contamination, radiation protection measures, radiation risk assessment

Environment International, Vol. 14, pp. 83-89, 1988

0160-4120/88 $3.00 + .00 Copyright © 1988 Pergamon Press plc

Printed in the USA. All rights reserved.

CONSEQUENCES OF THE REACTOR ACCIDENT IN CHERNOBYL IN THE FEDERAL REPUBLIC OF GERMANY: ENVIRONMENTAL CONTAMINATION, RADIATION PROTECTION MEASURES, RADIATION RISK ASSESSMENT Alexander Kaul Institute for Radiation Hygiene, Federal Health Office, Ingolst&dter Landstr. 1, D-8042 Neuherberg/ Munich, Federal Republic of Germany

(Received 18 August 1987; Accepted 10 May 1988) As a result of the Chernobyl reactor accident, and depending on the amount of precipitation, the Federal Republic of Germany experienced regionally quite varying degrees of radioactive fallout depositions: the southeastern regions of Bavaria had a '37Cs soil contamination of more than 40 kBq/m 2, in the Munich area the contamination proved to be about 20 kBq/m 2, north of the river Danube it was below 5 kBq/m 2. In consequence, and mainly due to '3'I and '3ZI'e, the local dose rate experienced an erratic increase (e.g., in the Munich area), from 0.08/xSv/h to 1 ~Sv/h within only a few minutes. On account of '3rCs and '34Cs depositions, the local dose rate today is still increased by about 50% in comparison to the time prior to the end of April 1986. In the Munich area, leafy vegetables were contaminated with '3'1 up to 20 kBq/kg, milk up to 1 kBq/l. Upon recommendations from the Radiation Protection Commission of the Federal Republic of Germany, the sale of milk with a '3'1 contamination of more than 500 Bq/l and of fresh leafy vegetables contaminated with '3'I by more than 250 Bq/kg was prohibited. These precautions were taken to limit the thyroid dose to infants to a maximum value of 30 mSv. A limit of foodstuff contamination by 137Csand '34Cs was not recommended, since the measured values and the amounts of food consumed, such as fresh leafy vegetables, milk and meat, were not expected to increase the dose per annum from natural sources by more than one third. Later, the EC-limits were established. Due to the Chernobyl fallout, the upper limit of the hypothetical genetic and somatic radiation risk from external and internal irradiation (inhalation of '3'I and ingestion of contaminated foodstuffs) of about 2 mSv lifetime committed effective dose equivalent lies within the range of one per thousand in comparison to the spontaneous mean genetic risk of 2-4%, or corresponds to an increase of about 0,002% of the spontaneous cancer mortality of 20% per year on the average.

Introduction

radionuclides in air; local dose rate; contamination of soil and vegetation; contamination of foodstuffs; total body activity in man. The extent of contamination was regionally quite different, whereby southern Germany was particularly affected due to strong rainfalls around the first of May. On the basis of results from measurements performed in numerous localities in the Federal Republic of Germany, the dose already absorbed, and the dose to be expected, could be assessed quite early after the reactor accident on the basis of appropriate radioecological models. The results from dose assessments for representative radionuclides clearly showed the radiation dose to the public from the contamination of the biosphere, as a consequence of the reactor accident in Chernobyl, to be far below the threshold for acute radiation effects. Late effects could not be excluded in

The radioactive substances released into the atmosphere on April 26, 1986, by the reactor accident occurred in the nuclear power plant Chernobyl, initially drifted into the Scandinavian region. During the first part of April 27th, the emissions passed across Poland in the direction of the Baltic Sea, but were then blown by changing winds in a southwestern direction. In the early days of May, these radioactive substances, together with the emissions from the reactor subsequently to April 27th, passed over the southern and western regions of Germany. After the first reports of increased radioactivity in air observed in Finland, an extensive measurement program was initiated in the Federal Republic of Germany whereby the following quantities were measured: total beta activity and concentration of selected 83

84 principle, although the first dose assessments already showed the expectation value of calculated genetic and cancer induction risk to be very small in comparison to the respective spontaneous risks. In this article the essential results from measurements of the environmental contamination, and the radiation protection measures taken are summarized. From the dose values expected for the population, radiation risk will be assessed.

1. Environmental Contamination The results from measurements of radioactivity in air, rain, soil, water, vegetation, and food stuffs may be summarized as follows: • In air were found radioisotopes of Iodine (~3'I, '3ZI'e/'a2I, '33I), Cesium ('34Cs, '3~s, ~37Cs) as well as of Strontium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium, Tellurium, Barium, Lanthanum, Cerium, Curium and Plutonium. The measured activity concentrations showed that Iodine 131 and the two Cesium isotopes '3aCs and '37Cs were of special importance due to their relative contribution to the total activity: on April 30th, prior to the onset of heavy rainfall, an activity concentration in air of about 210 Bq/m 3 was measured in the Munich area resulting to about 70% from the iodine isotopes 131,132Te/132Iand '33I, whereas the cesium isotopes '34Cs and '37Cs contributed to the total activity by about 6%. The contribution from 14°Ba and '4°La was approximately 4%, that of the remaining nuclides (99Mo, 99mTc, '°3Ru, '29mTe) about 14%. The activity concentration of alpha-emitters in the aerosol filters on May 1st was approximately 200 /~Bq/m 3 for 239~24°pu, 130 /xBq/m 3 for 238pu and about 200-1500 /zBq/m '~ for 242Cu. The radiochemical measurements of 9°Sr activity in aerosols yielded a ratio of approximately 1:100 in reference to '37Cs. The consequent activity concentration of 99Sr in air was about 0.04%. • In the afternoon of April 30th, strong thunderstorms occurred over southern Bavaria. Due to the high activity concentration of fission products in air at this time, a rapid increase of activity deposition on soil and vegetation followed together with an increasing beta- and gamma-dose rate: for example, the dose rate measured over meadow grass near the Institute for Radiation Hygiene increased within a very few minutes from 0.08/xSv/h (8/zrem/h) due to natural activity in soil and from cosmic radiation, up to 1 /zSv/h (100/xrem/h). At the end of 1986 the dose rate due to deposition of long-lived fission p r o d u c t s mainly '34Cs and "~7Cs- was still 0.12 /xSv/h (12 /zrem/h) and corresponded to an increase in the dose rate from natural environmental radiation by 50%.

A. Kaul • The total activity concentration of a rainwater sample taken in the afternoon of April 30th was about 50 kBq/l, of which approximately 85% could be attributed to '311, '3ZTe - - '321and '331, and about 6% to the cesium isotopes '34Cs and '37Cs. • The soil contamination of the sample meadow grass near the Institute for Radiation Hygiene amounted to about 400 kBq/m z after the rain, with a contribution of 70% from the radioiodine isotopes and 8% from the cesium isotopes. Referring exclusively to 137Cs, the soil contamination of the sample meadow was about 18 kBq/m z. In selected regions of southeast Bavaria values of more than 40 kBq '37Cs/m2 were measured. On the overall, the soil contamination from 137Cs was below 5 kBq/m 2 north of the river Danube, whereas to the south it amounted to about 20 kBq/m 2 on the average (see Fig. 1) (Winkelmann et al., 1987). *The radioiodine contamination of tap water, with the exception of water from cisterns, gave no reasons for concern with values mostly below a few Bq/1; particularly in reference to '37Cs, there is no future contamination of subsoil water to be expected because of its very slow vertical rate of distribution in soil. • Dry and wet deposition of fallout led to the contamination of vegetation: by deposition on the plant surfaces, by diffusion of radionuclides into plant material and by transfer via the soil-root-plant pathway. Radioactivity measurements of grass from the sample meadow near the Institute for Radiation Hygiene after the rain on April 30th resulted in values of about 8 kBq '3'I/kg and 2 kBq 137Cs/kg. These values were doubled by May 1st and then decreased for "~'I with a physical half-life of eight days. The contamination of field cultivated leafy vegetables (lettuce, spinach) measured in the Munich area during May 1986 was 2-20 kBq '3'I/kg and 2-9 kBq '37Cs/kg, that of field cultivated root vegetables 20-250 ('3'1) and 10-160 (137Cs) Bq/kg. In fruits there was a marked transport of radioactive Cesium (e.g. from the blossoms exposed to fallout into the ripe fruits). In red currents, for instance, activity concentrations of ':~4Cs and '37Cs of up to 600 Bq/kg were measured. In grain there was a marked difference between winter grain (essentially by contamination of the leaf surfaces) and summer grain sown in spring where radionuclide contamination is only via the roots. The values for winter grain were between 10 and 300 Bq 134 l:~TCs/kg' for summer grain between less than 5 and 100 at maximum. • For foodstuffs contaminated via the food chain, the pasture-cow-milk or -meat exposure pathways are of special importance in regard to radiation exposure. On account of the large regional variations of animal fodder contamination, only summarizing statements are possible:

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The contamination of cow's milk from dairies supplying the consumers in Bavaria, was in the range from 200 to 300 Bq ':~q 1 with a maximum around the 5th of May; the relative proportion of samples contaminated beyond the reference value of 500 Bq/I, as recommended by the German Radiation Protection Commission, was as high in Bavaria as 40% around the 5th of May.

M o t h e r ' s milk was contaminated comparatively low with 131I, maximum 30 Bq/l, and with 13rCs clearly below 10 Bq/l. B e e f was regionally quite varyingly contaminated, in the Federal States of Hessen and Rheinland-Pfalz primarily below 100 Bq 137Cs/kg by the middle of May, in Bavaria up to 500 Bq/kg, in July up to 800 Bq 137Cs/kg; the highest meat contamination was measured in g a m e (deer) in Bavaria during the first half of May of up to 700 Bq 13q/kg and 2,000 137Cs/kg; in June up to 3,500 Bq 137Cs/kg in single cases.

A. Kaul

Table 1. Estimated upper levels of the committed effective dose equivalent and organ doses from the first year (May 1986 to April 1987) after the Chernobyl accident, based on fallout data measured in the Munich area. Organ doses (roSy) Comm. eft. dose equivalent (mSv)

Age group Type of exposure

Thyroid

Bone marrow, Gonads

Infants (0-10 years) inhalation and ingestion external "/-irradiation

3-13 0.3-0.6

0.3-0.7 0.3-0.6

0.4-1 0.3-0.6

Total

3.3-13.6

0.6-1.3

0.7-1,6

Adults inhalation and ingestion external 3,-irradiation

0.5-2.5 0.1-0.3

0.3-0.6 0.1-0.3

0.4-0.8 0.1-0.3

Total

0.6--2.8

0.4-0.9

0.5-1.1

2. Radiation Protection Measures Results from measurements of soil and vegetation contamination during the first days after the reported accident showed that 131I and 137Cs incorporations were to be expected from the consumption of plant and animal foodstuffs which could hardly be considered as a risk for the population. Nevertheless, the German Radiation Protection Commission considered possibilities of avoiding unnecessary radiation exposure by achievable counter measures. On the basis of recommendations from the Radiation Protection Commission, the following precautions were taken: • Milk with a 1311activity concentration of more than 500 Bq/1 was not allowed to be sold for the purpose of keeping the thyroid dose to the infant below 30 mSv (3 rem) from a milk consumption of 1 1 per day with an activity concentration of 500 Bq/1 over a week and consecutive decrease of radioactivity due to physical decay. • Since other foodstuffs (e.g., fresh leafy vegetables), were also contaminated with 131I, an upper limit of 250 Bq/kg was put on fresh leafy vegetables available for sale, considering a decontamination factor of 5 and less from cleansing. • Due to a reduced contamination from peeling of certain vegetables and fruits, and due to the low daily amounts ingested of such foods as herbs, teas and honey, there was no need to propose upper limit reference values for the contamination of these products with 1311;this also applied to 137Cs as major contaminant next to 134Cs after the physical decay of 131I.

• No limitation was required for tap water, except for the recommendation not to drink water from cisterns. • On the basis of an assumed higher than average '37Cs contamination of meat, leafy vegetables, milk or

milk products of 1,500 and 300 Bq/kg, and 300 Bq/l, and by estimating a mean consumption rate of 10, 5 and 30 kg for a period of three months after the reactor accident, the German Radiation Protection Commission calculated an effective dose equivalent of 0.6 mSv (60 mrem), a value not giving cause for a recommendation of reference levels for 137Cs contained in various foodstuffs. With the intent of minimizing the radiation detriment from contaminated foods imported from non-EC-countries, the Commission of the European Communities decided to limit the contamination of foodstuffs to 370 Bq ~7'la4Cs per kg or per 1 for milk, milk products, and baby foods, and to 600 Bq/kg for other food items.

3. Assessment of Radiation Dose and Risk Radiation dose

On hand of numerous nuclide specific measurement results of activity concentrations in air, soil, vegetation, and foodstuffs, and of the outdoor dose rate, it was possible by means of radioecological models to assess the upper level of presently and future absorbed radiation dose for the population in different regions of the Federal Republic of Germany. The results may be summarized as follows (Verrff. SSK, 1986) (see Tables 1 and 2): • The effective dose equivalent was predicted to be 0.7 to 1.6 mSv (70 to 160 mrem) for infants between 0 and 10 years in the Munich area during the first year after the reactor accident and 3 to 5.5 mSv (300 to 550 mrem) for the expected life time of 70 years. • The values of effective dose equivalent for the adult were 0.5 to 1.1 mSv (50 to 110 mrem) during the first year and 1.5 to 4 mSv (150 to 400 mrem) for 50 years.

Consequences of reactor accident

87

Table 2. Estimated upper level of the expected lifetime committed effective dose equivalent, based on fallout data measured in the Munich area.

Age group Infants (0-10 years)

Type of exposure

inhalation and ingestion

Comm. effective dose equivalent (roSy)

Total comm. effective dose equivalent (rnSv)

1-2.5 3-5.5

external y-irradiation Adults

inhalation and ingestion

2-3 0.5-2 1.5-4

external y-irradiation

1-2

• According to the available activity measurements in different regions of the Federal Republic of Germany the local doses were expected to be between 1/10 and the twofold amount in selected regions of southern Bavaria. Based on the results from total body measurements performed in children (aged 2 months to 13 years) from the Munich area during the month of May, 1986 at the Institute for Radiation Hygiene of the Federal Health Office, a mean thyroid dose of (2.6 _ 1.2) mSv ((260 ___ 120) mrem) was calculated from the intake of '3'1 by inhalation and ingestion (Schmier, 1986). The time dependence of 137'134Cs total body activity in man has been additionally determined by regular total body measurements. The results of these measurements in reference groups (men, women, and children from the Munich area) show that the actual effective doses calculated from total body measurements are, on the average, considerably smaller than the above values, having been predicted during May/June, 1986 for the exposure pathway ingestion during the first year after the reactor accident. These values are 0.07 mSv (7 mrem) for the adult and 0.05 mSv (5 mrem) for women and children (Munich area). For children from the lower alpine region the effective dose from '37,'3~Cs predicted from total body measurements is 0.08 mSv (8 mrem) during the first year after the accident (Schmier, personal communication).

3.2 Radiation risk There are two approaches for assessing the extent of risk from late effects: comparison of the additional radiation dose from the Chernobyl accident with the radiation exposure from natural sources; quantification of late effects based on the risk coefficients derived from epidemiological studies. Both approaches

were used and late effects assessed for thyroid carcinoma, embryo and fetus, genetic effects, and total somatic radiation risk.

3.2.1 Comparison with natural radiation exposure Natural radiation exposure results from the following sources: cosmic radiation, internal radiation exposure due to inhalation or ingestion of natural radionuclides and natural environmental irradiation. The sum of contributions from these components yields in the Federal Republic of Germany a mean effective dose equivalent of approximately 2 mSv per year (200 mrem per year). For 70 years of life the mean natural radiation dose is approximately 150 mSv (15 rem), subject to a considerable variation width which, for the Federal Republic of Germany, comprises a range between approximately one half and threefold of the mean value given above. A comparison between the upper limit of radiation dose resulting from the Chernobyl accident for the adult population in the Munich area during the first year after the accident and that from natural radiation shows an increase of natural dose by approximately 25% to 55%. When referred to the total lifetime, this enhancement is approximately 1% to 5%. Due to the rather high deposition in Bavaria, the increase of radiation dose for the larger part of the population of the Federal Republic of Germany is expected to be no more than 1% of annual natural radiation dose. 3.2.2 Assessment of late effects In reference to the following considerations, an upper bound of the effective dose equivalent of the 2 mSv (200 mrem) for the total lifetime is assumed for the population of the Federal Republic of Germany in consequence of the Chernobyl reactor accident. 3.2.2.1 Thyroid carcinoma For deriving - - on the basis of a linear no threshold hypothesis - - a calculated value for increased thyroid cancer mortality due to irradiation from Chernobyl fallout, the following assumptions are used: mean thyroid dose for infants and children between 0 and 10 years of age: 3 mSv (300 mrem); mortality during total lifetime due to thyroid cancer after therapeutic external irradiation of infants and children: 10 x 10-4 S v - ' (10 x 10-6 rem -1) using the risk coefficient of UNSCEAR (1977); reduction of the effectiveness of '3'I as compared to external radiation by a factor of three as used in NCRP Report 80 (National Council of Radiation Protection and Measurement, 1985). The natural mortality from thyroid carcinoma during the following 50 years in a group of children 0 to 10 years of age is 1:10,000. From the aforementioned data emerges a calculated increase of thyroid cancer mortality in children during the following 50 years of 1%, or 1 case in a million. In reference to the induction of

88 thyroid c a r c i n o m a b y radiation, this represents a hypothetical increase o f a p p r o x i m a t e l y 2%.

3.2.2.2 Teratogenic effects Basically, the following radiation induced effects m u s t be considered: death of e m b r y o or fetus, m a c r o s c o p i c a l - a n a t o m i c a l malformations, especially o f the skeleton and, additional developmental anomalies, especially o f the central n e r v o u s system. An u p p e r b o u n d of the effective dose equivalent of a p p r o x i m a t e l y 2 m S v (200 m r e m ) to pregnant w o m e n and thus to e m b r y o and fetus is not e x p e c t e d to induce d e v e l o p m e n t a l disorders. F r o m medical experiences and from data collected on the d e s c e n d a n t s of H i r o s h i m a and N a g a s a k i survivors, such disorders m a y be e x p e c t e d - - e v e n in the m o s t sensitive stages o f p r e g n a n c y - - o n l y when threshold doses in the o r d e r of 50 m S v (5 rem) acute irradiation are exceeded (Ver6ff. S S K , 1985). Subsequently, the G e r m a n Radiation Protection C o m m i s s i o n in their r e c o m m e n d a t i o n of May 16th 1986 have stated (Verrff. S S K , 1986): " . . . the radiation exposure in the Federal Republic of Germany due to this accident is comparatively low and will be comparable to the exposure from natural radiation during 1 year. Precautionary measures for the consumption of milk, milk products and vegetables resulted in a reduction of radiation exposure. A detriment to unborn life is not to be expected... An abortion due to the radiation dose from the Chernobyl accident is in no case justifiable... " It m a y be mentioned that an abortion is indicated, according to a r e c o m m e n d a t i o n of the G e r m a n Radiological Society, only after radiation doses of at least 100 to 200 m S v (10 to 20 rem). Additionally, for abortions after the 8th w e e k of p r e g n a n c y , a rate of complications from surgical intervention is reported of 12% with a 0.15%o fatality rate (Stieve, 1986).

3.2.2.3 Genetic effects A s s u m i n g an u p p e r b o u n d of an additional dose to the g e r m cells of 2 m S v (200 mrem) f r o m the Chernobyl accident in the Federal Republic of G e r m a n y , the Radiation Protection C o m m i s s i o n concluded (Verrff. S S K , 1986): "Based on the results of experimental radiation genetics, 2-4% of normally occurring mutations may be attributed to the natural radiation exposure in the course of one generation. In the Federal Republic of Germany this would result in an increase of the natural mutation rate of a few %odue to the Chernobyl accident." Referred to the rate o f 2-3% o f n e w b o r n s with any significant genetic defect, this m a t h e m a t i c a l l y derived m i n i m u m increase in mutation rate could not be observed in practice.

3.2.2.4 Total risk o f somatic late effects T h e International C o m m i s s i o n o f Radiological Protection (ICRP) and the United Nations Scientific C o m m i t t e e on the Effects o f Atomic Radiation ( U N -

A. Kaul S C E A R ) h a v e derived a risk coefficient for radiation induced c a n c e r mortality in the order of 1% per Sv (0.01% per rem) effective dose equivalent b y extrapolating the radiation induced cancer mortality observed after high doses and using a linear dose/risk relationship. Accordingly, an increase of c a n c e r mortality of 0.002% m a y be attributed to 2 m S v (200 mrem) a s s u m e d as an u p p e r limit for the additional radiation dose from the Chernobyl accident in the Federal Republic of G e r m a n y . In c o m p a r i s o n , the probability for m e m b e r s of the population of the Federal Republic to die from cancer is presently a p p r o x i m a t e l y 20%. Therefore, the hypothetical radiation induced c a n c e r mortality in c o n s e q u e n c e of the Chernobyl reactor accident is small in c o m p a r i s o n to the temporal and regional variation of natural c a n c e r mortality.

Summary The organ dose values in the Federal Republic of G e r m a n y during the first y e a r after the reactor accident in Chernobyl are in the range o f the annual natural radiation exposure or - - referred to the effective dose equivalent - - c o r r e s p o n d to not m o r e than 50% of the m e a n annual dose from natural radiation. In reference to total lifetime, the u p p e r limit of the additional c o m m i t t e d dose equivalent due to radioactive fallout a m o u n t s to a p p r o x i m a t e l y 1-5% of the natural radiation dose during this period. F o r most of the population of the Federal Republic o f G e r m a n y the relative increase is expected to be not m o r e than 1%. F o r children from regions with relatively high activity contamination (Munich region) one additional radiation induced thyroid c a n c e r mortality in a million m a y mathematically be derived on the basis of risk coefficients f r o m ep~demiological investigations in children who were therapeutically irradiated. In reference to radiatiorr caused d e v e l o p m e n t a l disorders, the radiation doses actually a b s o r b e d were considerably below threshold values established for these types of effects. Based on animal experiments, an increase of the spontaneous mutation rate in the order o f a few %0 m a y be derived mathematically. Assuming a spontaneous risk of about 20% for an individual to die from cancer, the additional radiation dose in c o n s e q u e n c e of the Chernobyl accident would contribute to an increase in this probability to 20.002% in the Federal Republic of Germany.

References Auswirkungen des Reaktorunfalls in Tschernobyl in der Bundesrepublik Deutschland (1986); Empfehlungen der Strahlenschutzkommission zur Absch~itzung, Begrenzung und Bewertung. VerOffentlichungen vom Bundesminister ftir Umwelt, Naturschutz und Reaktorsicherheit; Gustav Fischer Verlag, Stuttgart, New York.

Consequences of reactor accident

Comprehensive Reports on the Reactor Accident in Chernobyl Der Unfall im Kernkraftwerk Tschernobyl. Teil l: Zusammenfassung und Bewertung vorliegender Informationen zur Anlage und zum Unfallablauf. Teil 2: Radiologische Auswirkungen in der Bundesrepublik Deutschland. Stand 10.06. 1986. Gesellschaft f/dr Reaktorsicherheit (GRS) mbH; GRS-s-39 (Juni 1986). Umweltradioaktivit/it und Strahlenexposition in S/ddbayern durch den TschernobyI-Unfall. Bericht des Instituts f/dr Strahlenschutz der Gesellschaft f/dr Strahlen-und Umweltforschung mbH M/dnchen: GSF-Bericht 16/86. Kaul, A. (1986) Reaktorunfall von Tschernobyl: Quantifizierung und Bewertung des Strahlenrisikos. Pharmazeut. Ztg. 131(26), 1500-1504. Kaul, A. (1986) Reaktorunfall von Tschernobyl: Fakten, Marlnahmen, Konsequenzen. Fleischwirtschaft, Heft 10, 66. Jahrgang. Oktober 1986. Kaul, A. Bewertung der Strahlenexposition der Bevblkerung als Folge des ReaktorunfaUs in Tschernobyl. In: Das 6ffentliche Gesundheitswesen 2/87, Georg Thieme Verlag Stuffgart-New York. National Council of Radiation Protection and Measurement (1985) Induction of thyroid cancer by ionizing radiation. NCRpo Report 80, Bethesda MD. Neuere Erkenntnisse zum Unfall im Kernkraftwerk Tschernobyl Tell l: Zusammenfassung und Bewertung der Informationen zur Anlage und zum Unfallablauf. Teil 2: Radiologische Auswirkungen in der Bundesrepublik Deutschland und im europ~iischen Ausland Gesellschaft f/dr Reaktorsicherheit (GRS) mbH; GRSS-49 (November 1986). Radioaktivitf.t und Strahlenfolgen: Messen-Absch~tzen-Bewerten (1986) In: Mensch + Umwelt, ein Magazin der Gesellschaft fiir Strahlenund Umweltforschung M/dnchen, Dezember 1986.

This study is based on published data in the above listed comprehensive reports.

89

Schmier, H. (1986) Ganzk6rperuntersuchungen an ausgew~ihlten Personengruppen, in GSF, Mensch und Umwelt; Radioaktivitgtt und Strahlenfolgen: Messen-Absch/itzen-Bewerten, Dez. S. 49. Schwibach, J. (1986) Auswirkungen des Reaktorunfalls in Tschernobyl auf den Raum M/dnchen; ISH-Heft 103, November 1986, Stieve, F.-E. (1986) Akzeptanz yon strahlenbedingten Risiken; Vortrag anl/ifllich der 27. Jahrestagung der Vereinigung Deutscher Strahlenschutz/irzte am 23./24. Mai in M/dnster/Westfalen. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (1977) Sources and effects of ionizing radiation. Report to the General Assembly, with Annexes. United Nations, New York. Winkelmann, I. et al. (1986) Ergebnisse von Radioktivitatsmessugen nach dem ReaktorunfaU in Tschernobyl; ISH-Heft 99, September. Winkelmann, I. (1987) Radioactivity measurements in the Federal Republic of Germany after the Chernobyl accident. ISH-Heft 116, September. Winter, M., V/dlkle, H., Narrog, J., Meyer, P., Kirchhoff, K. (1986) Die Radioktivit~it in der Bundesrepublik Deutschland und in der Schweiz nach dem Reaktorunfall in Tschernobyl; Ergebnisse einer Me/3werterhebung des Arbeitskreises Umwelt/dberwachung. In: Fachverband f/dr Strahlenschutz e.V.; FS-86-39AKU, Oktober 1986. Wirkungen nach pr~.nataler Bestrahlung (1985). Ver/dffentlichungen der Strahlenschutzkommission, Band 2; herausgegeben vom Bundesminister fiir Umwelt, Naturschutz und Reaktorsicherheit; Gustav Fischer Verlag, Stuttgart, New York.