inini XAn5C0109

RECENT DEVELOPMENTS IN RADIOECOLOGY

M.Tschurlovits

Atominstitute of Austrian Universities, Schüttelstraße 115, A-1020 Vienna, Austria

ABSTRACT The international development of the field "radioecology" in the last decade with a short glance to earlier periods is shown. Present activities are discussed. Both assessment and modelling approaches are going to become more developed. The present developments lead to the conclusion the existing problems can be solved only by cooperation of measurements and modelling. This collaboration is important for not to leave the field to groups, directed by politicians seeking for short term gain, in order to give retrospective justification in a specious manner of decisions not be based on objective analysis.

INTRODUCTION Radioecology is considered to be one of the younger fields in protection, but the roots go back to the dawn of the development of radiation protection in general. Definition and terminology radio.. derived from Mdm Curies initial definition ecology.. greek access ( house, immediate environment of man; coined by Heckel (1834-1919 ), medical practitioner in Jena. Later established by Worrming. Present scientific definition (not identical with political interpretation): relation between mankind and environment. Radioecology: 1956 as Radiation ecology coined (USA, USSR ) Today the term "radioecology" is interpreted as: • understanding the behaviour of radioactive material in the environment (Ts 84) • science of the effects of to living and non living environment ( Bo 93)

These definitions are very general. Therefore, a further specification is required, which is only possible by definition of a purpose. It has therefore to be distinguished between scientific and practical objectives of the programmes. Further it is possible to distinguish between different types of programmes: 1) MONITORING PROGRAMMES: demonstration of compliance with limits (assessment of activity in a given compartment (e.g. activity concentration in air independent from the source), recently also dose estimates ( e.g. Lo /9 Iff/) 2) RADIOECOLOGICAL PROGRAMMES: basic criteria for the transfer of radioactive materials in environmental compartments, investigations on transfer parameters, development of models for retrospective dose estimation and prediction of doses for different conditions ( e.g acute and chronic releases ) (e.g /IA 93,94/) 3) ECOLOGICAL PROGRAMMES: assessment of risk factors from empirically assessed exposure conditions ( e.g health effects from radon ) (e.g.St 93 ) The results of programs attributable to the first two groups lead are usually reliable and consistent, taking into account inherent variability. Ecological programmes lead at present only under particular conditions to proved results. This is mainly because too many parameters are needed for evaluation, but only a few are sufficiently well known. Therefore the conclusions may depend rather on the assumption of parameters than on real parameters. ( see St /93/ for the relation between Radon and lung cancer). In general, the programmes are established for different purposes and can not be consistent. When data are used for another purpose as they were established, misleading conclusions may result.

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DEVELOPMENT OF RADIOECOLOGY The development in time can more or less arbitrarily separated into five phases and a precursor. The phases are obviously in close relation to the general development in the fields of ( mainly development of radiation detectors ), radiation biology and epidemiology ( risk factors ), radiation standards ( organs of interest) etc. A few examples are shown below. Precursor: epidemiological studies before discovery of radioactivity /Hä 79/; /Sc 93/reports even on much earlier reports on miners diseases as by Paracelsus 1567 measuring approaches: determination of Ra-A in air and water (Ba 07, Sc 13), cosmic rays ( He 29 ). phase 1 (until 1960) • assessment of activity concentration in environmental materials • source: nuclear weapons test • mainly used detector: gross beta • results: activity concentration gross beta • presentation of results:tables , no interpretation • development: dose commitment ( Lindeil, UNSCEAR 1958) • selective measurements: mainly based on chemical separation ( Sr-9o) phase 2 (about 1960 -1970 ) • development of research programs , mainly in relation to use of nuclear energy, use of • recognition of natural background phase 3 pre Chernobyl ( about 1970-1986) • advent of environmental awareness • improvement of measuring techniques ( spectroscopy, low level measurements) • dose assessment • development of prediction models • improvement of conceptual background • increase of public interest by political influences of "quasicritical" groups with a background in contradiction to scientific basic • assessment of natural background phase 4 past Chernobyl (immediately after 1986) • avalancing increase of the number of "experts" in radioecology, number in the meantime decayed to pre-Chernobyl level • interaction between political and scientific issues • development of scientific basis for decision makers overruled by political influences • dose predictions phase 5 present development Among other activities, the following large programs are in progress: empirical dose assessments a) retrospective dose assessments of previous emissions Hanford, Wismut, Maralinga&Emu, Kyshtym, Nevada test site (IAEA 94) Semipalatinsk (ST 95) b) doses assessment after Chernobyl c) Radon programmes model development d) improvement of models e) model validation f) predictive models h) default parameter sets of environmental parameters

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Some examples • Estimation of the doses of Wismut workers/ Ei 93/: annual doses of uranium miners were in the early years (to 1955 ) in the range of 30-300 WLM, later decreasing. ( 10 WLM=»50 mSv) • Hanford Dose reconstruction project / Na 93/: the routine releases in the Columbia river 1955 bis 1959 were in the order of 1015 Bq (gross beta activity). The migration of these radionuclides is investigated. • Dose reconstruction in nuclear test sites e.g: Maralingu and Emu (Australia ) /Wi 94, Ha 94/: The area was contaminated with Pu-isotopes and is still occupied by aborigines. The dose by inhalation is the most important pathway. • Continuation of model development and parameter assessment IAEA Handbook on Parameter values for prediction of transfer in temperate environments (1994) Model validation IAEA: VAlidation of Model Predictions ( VAMP), The International Chernobyl Project BIOMOVS: BlOsperic MOdel Validation Study ( CDN,SP,SW) an international study to test models designed to predict the environmental transfer and bioaccumulation of radionuclides and trace substances

IUR: International Union of Radioecology : scientific basis, collaboration with CEC CEC: support of projects to provide a scientific basis for decision making in accidental cases.

CONCLUSIONS It can be seen that substantial effort is put into both model development and measuring programs. Even if we consider only institutions which have the aim of an objective judgement of the environmental situation, neither the progressive modelists nor the pragmatic measuring engineer can solve the existing problems alone. Uncertainty assessment and sensitivity analysis may keywords. Both groups need the interaction with the other to prevent irrationalism. This collaboration is also important for not to leave the field to groups directed by politicians seeking for short term gain in order to give retrospective justification in a specious manner of decisions not be based on objective analysis.

REFERENCES

/Ba 07/ M.Bamberger: Beiträge zur Radioaktivität der Mineralquellen Tirols Sitzungsberichte der Österr. Akademie der Wissenschaften Vol CXVI Dez. 1907. BIOMOVS II Progress reports, Technical reports, Newsletter/Bo 93/ H. Bonka: Entstehung des Begriffes Radioökologie Wissenschaft und Umwelt 1/93 p.31. /Ei 93/ G.G.Eigenwillig et al: FV für Strahlenschutz: Strahlenexposition und strahleninduzierte Berufskrankheiten am Beispiel Wismut FS-92-62/2-AKURA (1993). /Ha 94/ S.M.Haywood, J.G.Smith: Assessment of Potential Doses at the Maralinga and Emu Test Sites IAEA TECDOC-755(1994). /Hä79/ F.H.Haertling, W.Hesse: Der Lungenkrebs, die Bergkrankheit in den Schneeberger Gruben Vierteljahresschrift f. gerichtliche Medizin Vol XXX 1879 ( 3 parts). /He 07/ V.F.Hess, R.Steinmaurer: Neuere Ergebnisse der Registrierung der kosmischen Ultrastrahlung auf dem Sonnblick Helv.Phy.Acta III (1929). /IA 93/ IAEA 93: Validation of Environmental Model Predictions (VAMP) program outline. /IA 94/ IAEA 94:: Assessing the radiological impact of past nuclear activities and events: IAEA TECDOC-755 (1994). /IA 94/ IAEA 94: Handbook of Parameter Values for the Prediction of Radionuclide Transfers in Temperate Environments (Technical Series 364) 1994. /IA 94 BSS/ Basic Safety Standards Safety Series 115 1 (1994). /IAEA 95?/ Safety series 57: new edition in progress. /Lo 91/ H. Loosli et al:30 Bericht der Eidg. Kommission zur Überwachung der Radioaktivität 1987-88 (1991).

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/Na 93/ B.A. Napier et a(: Environmental Modelling for the Hanford Environmental Dose Reconstruction Project (1993) BN-SA-HEDR. /Sc 13/ E.Schrödinger: Beiträge zur Kenntnis der atmosphärischen Elektrizität LI Sitzungsberichte der Österr. Akademie der Wissenschaften Vol CXXII Dez.1913. /Sc 93/ W.Schüttmann.Historical perspectives in occ. Medicine Am.J.Ind.Med 23 (1993)355. /Si 93/ C.Stidley: A review of ecological studies of lung cancer and indoor radon Health Physics 65 (1993)235-25. /St 95/ P.Stegnar: Radiol. situation at the Semipalatinsk nuclear test site, this meeting. /Ts 84/ M.TschurlovteLecture notes, TU Wien Radioökologie, 1984 ff. /TS 95/ M.Tschurlovits, G.Winkler: On the use of a deterministic model for prediction of radionuclide concentration in water Proc.IAEA SM 339/128, in press. U.I.R: Newsletter Quarterly 1991 ff,, Information Bulletin, Textbook in preparation. /Wi 94/ G.A. Williams: Dose assessment studies at former nuclear weapons test sites in Australia 1993 IAEA TECDOC-755(1994).

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