Natural Radiation Environment

f 6 r SECOND SPECIAL SYMPOSIUM

ON NATURAL RADIATION ENVIRONMENT

JANUARY 19-23- 1981

ABSTRACTS

fleoc/i Sonrfs of Kerala

BHABHA ATOMIC RESEARCH CENTRE BOMBAY. INDIA SECOND SPECIAL SYMPOSIUM ON NATURAL RADIATION ENVIRONMENT

Hosts : Bhabha Atomic Research Centre Bombay-400 085, India Sponsors : Department of Atomic Energy, Government of India Indian Association for Radiation Protection Advisory Committee JAS Adams, USA, Chairman A Bauman, Yugoslavia M Eisenbud, USA H Jammet, France Z Jaworowski, Poland A Kuzin, USSR D Oakley, USA E E Pochin, UK J Pohl-Rueling, Austria W Seelentag, FRG K Sundaram, IAEA l< G Vohra, India M Wilkening, USA Organising Committee K G Vohra, Convener JAS Adams T F Gesell W M Lowder J E McLaughlin K C Pillai T Subbaratnam U C Mishra, Secretary Local Arrangements Committee U C Mishra, Convener L. U Joshi V A Kamath K S V Nambi P P Pai S Sadasivan T Subbaratnam C M Sunta SECOND SPECIAL SYMPOSIUM

NATURAL RADIATION ENVIRONMENT

JANUARY 19-23, 1981.

BHABHA ATOMIC RESEARCH CENTRE BOMBAY, INDIA

ABSTRACTS Author index with session numbers are given at the end. Session numbers and paper numbers are given on the top of each page. CCWUT3ICXS DShIVED PI:OK THE 1975 CONPSSEKCE OS A52AS O? HIGH KATÜltAl JJATUFAL RADIOACTIVITY

iï. Sisenburi !?•» York university Kedical Center fuxedo, mr 10987» USA

Tbe first International Synposiua on Areas of High Eatural Radioactivity «as held in Pocos de Caldaa, Brazil in June, 1975» The conference was attended by 93 scientists froa 16 countries, «ho discussed a wide range of geological radioactive anomalies. The proceedings of the conference were published by tbe Brazilian Academy of Sciences in 1977* At the conclusion of the conference, representatives of both IAEA aid WHO expressed an interest in developing a program of international collaboration which would encourage their me&ber states to locate and describe the characteristics of areas of high natural radioactivity. It was hoped that a number of services would be offered, including central laboratory facilities for analysis of Ra-226 and other heavy radionuclides in samples of food and water collected by investigators in parts of tbe world where local facilities might not be available. Because of the importance of quality control, it was suggested that IAEA should take such steps as are necessary to assure intercomparability of measurements made by investigators in the various high background ureas* Because of the apparent association of high levels of Ra-226 in public water supplies known to be derived from aquifers in contact with sandstone, fractured granite or black shales, it was recommended that samples of water from such source* be sampled for Ra-226 and, as necessary, Pb-210 and Po-210. It was recommended that the location of faros and pasturelands where the soils are known to contain uraniferous minerals should be identified by soil scientists throughout the world, and that samples of foods from such areas should be «analyzed for Ra-226 and other heavy radionuclides» Recommendationa were also aade for a coordinated study of the relationship between -type of habitat construction aad exposure of tahabitantti to tbe radon series*

- 1 - I 2

SHCÜlD THE SEPOSUHE TO ÜATDBAL SOURCES OF RADIATION Bf REGUIATJK» AND IN WHAT ÏÏAÏ ?

1. Jaanet Instltut De protection et de 3uT«t* Buclaire ?ontea»j Aux Boaea franc*

- 2 - TRACK DETECTORS FOR ENVIRONMENTAL RADON STUDIES: RADON CONCENTRATIONS IN THE GROUND

Robert L. Fleischer and Antonio Mogro-Oampero General Electric Research & Development Center Schenectady, NY 12301 USA

Systematic flow of fluids in the earth could have important consequences. It could redistribute elements geochemieally and consequently produce or destroy mineral deposits"; or it could provide an agent for transport of trace elements or isotopes from within or near such deposits. The diverse topics that these possibilities suggest include both the study of the origin of mineral resources and exploration methods that rely on distinctive signals. The signals could be gases- hydrocarbons from petroleum or natural gas deposits, noble gases from the decay of uranium or thorium, or other volatiles that are derived from minerals. The security of subterrestrial waste disposal is another topic to which fluid flow is critical. A prime tracer for gas flow in the earth is Rn-222, which has the virtues of not interacting chemically with the earth, since it is a noble gas, and of being readily measured at minute levels due to its alpha radioactivity. Solid state track detection has been developed in recent years such that it can give reliable Rn-222 readings, integrated over time, free from interference from Rn-220 or other terrestrial radioactivity.

Track techniques for measuring radon concentrations and fluxes will be reviewed and recent observations of variations of radon in the ground will be surveyed and their implications for fluid flow considered.

As an example of a well documented site we describe results at a site near Thoreau, New Mexico. There Rn-222 measurements at 60 cm in the earth show background patterns that can be remarkable reproducible over time. The readings taken at monthly intervals over a 13-month period for a set of 55 positions give different, but nearly constant monthly readings at each position, the typical standard deviation being 22% (see Fig. 1). Superimposed on thai stable pattern and extending over more than 2 years time have been four periods during which spatially grouped radon readings increased by a factor of 2 or more over their normal values (see Fig. 2). The simplest description of the-source of the increases is sporadic puffs of upflowing gas, originating at as yet unknown depths. Alternative interpretations are considered, and such factors as precipitation, temperature, atmospheric pressure, and earthquakes are found to be uncorrelated with the events. Separate periods of mostly low radon values may be due to downflow of gas.

Figure 1 displays the reproducibility of month-to-month readings for holes that show an event and ones that do not. Measurements in deeper holes located near one corner of the array over the last 18 months show the same radon increases and establish that the effect extends to at least 600 em depth.

The patterns in Figure 2 are not yet understood. The only possible cause of which we are aware that can presently not be ruled out is earth-tidal fluctuations, which could only act as a trigger. Even if such fluctuations were found to be well correlated with the upflows, they would leave unresolved the question of what physical phenomenon is responsible for the effects.

- 3 - I»TB Figure I- Variations of track- MEDIANS : production rate with time: Top: Progression of the Tnedian of 55 readings. Center: Variations at 3 nearby holes. Bottom: Varia- tions at three holes showing a simultaneous increase at month 2., (2.2-KTtracks/cm -30d=l dps/cnT) JHXI

|M0 [wo ' 10 90

M 20 I I I I O-J I I

Figure 2- Variation with times of unusually high readings (£1.6 times the usual value at each individual site) and unusually low readings (*0.62 times the usual value).

- 4 FAST A525 J^WSBS? 71-7V. IS THE Air? CASE TO "TÏI3 ?ROBLS» 0? SI5B SAr^ëJii. B

G.'J. MaatiEU I*borator\o j

CM. Sunta, M. David, M.C. Abani, A.S. Ba«u and K.5.V. Bambi Health Phyaica Division Bhabha Atonic Research Oentre Bombay-400 085» India

Southern coast of India ia scattered with patches of momazite bearing sands. Two large and most concentrated deposits are at : 1) Chavara-Neendakara in Quilon Dist, Kerala and (2) lianavalakuriehi- Midalam in Kanyakumari Dist. tTamil Nadu. Other minor and Isolated patches of lower cocf«ntration are found at a number of placea along the west as well as the east coast* In an earlier survey external radiation exposure measurements were carried out covering a population of about 70,000 people living in tile 55 km long coastal strip in Kerala. The measurements were carried out with natural CaF TLD in about 2500 dwellings and 10,000 persons selected on random basis. The present paper deals with the statistical analysis of these dosimetric data. These consist of 11,108 values which include personal exposure of 8770 persona and house exposures in 2338 dwellings* The data are ranked in the annual exposure internals of <100, 100-200, 200-300, upto 3800-3900 mH per year. The upper- most bracket is determined by the fact that the highest value is 3840 mfi per year, for the dwellings and 3260 oB per year for the personal exposure. The paper presents i) frequency distributions in the above exposure ranges for the dwellings as well as for the resident population are plotted. . The data are presented in this form separately for the three occupational groups namely, i) residing in the area but working elsewhere; ii) working in the household and iii) fishermen. 2) The probability distribution of the exposure values is attempted by fitting the relative cumulative frequencies on a normal probability graph. The fitting of the data into the most often observed log-normal distribution is examined. The average and standard deviations are calculated for each segment of the area as well as for the whole area of the survey. 3) The ratio between the exposure inside the dwellings and the exposure received by the respective residents is calculated for eacn case. This correlation study is carried out separately for each of the three occupational groups to see to what extent the mobility of the individuals affects their radiation exposure value. 4) Average population and dwelling exposures for individual segments of the total area of survey are caloulated. The segments are geographically contiguous and the pattern of average exposures have a nearly continuous variation starting from 135 mB/yr in the northern segments, increasing to 900 mB/yr at Chavara and then tapering down to 500 mB/yr at the southern «oat segment* The population In each of these segments range» between 2500-3500 persons. 5) The eoUectire dose to the present estimated population of about 92,000 persona in thi« are* works out to about 33000 peraon-rems. The survey is being extended to other ureas; the recent me-*—->-ea:eat carried out at ifenavalaJcurichi-illdalam area, with a portable survey meter are also presented. The values rang* from 15 uH/ar to 800 uB/nr. ENHANCED NATURAL RADIATION EXPOSURE DUE TO ENRICHED HEAVY MINERALS AT THE COAST OF NOTHERN GERMANY

H. Bonka Lehrstuhl fiir Reaktortechnik Rhein.-Westf. Technische Hochschule Aachen Eilfschornsteinstrafie 18 Aachen, Federal Republic of Germany

In the Federal Republic of Germany, the natural local dose rate varies very differently. The lowest values of approximately 2o to 4o mrem/a are found in the northern part of Germany (sandy soil) and in the Lower Alps (calcareous soil). Up to now we believed that the highest local dose rate not influenced by man is located in the Bavarian- or Black Forest, with approximately 25o mrem/a.

On streets and in tcvns of the northern part of the Federal Republic of Germany the local dose rate became enhanced by the use of granite and basalt stones. Further changes of the radiation exposure on streets are the result of using slagstones. Copper . slagstones from Mansfeld in the German Democratic Republic have a 238u-activity of nearly 2o pCi/g.

In 1978, measurements of the natural radiation exposure at the beach of the island Norderney resulted in a natural gamma dose rate which might be more than 1o times enhanced. The Fig. 1 shows e.g. the measured local dose rate at the beach of Norderney at Oktober 1979. The place with an enhanced gamma radiation exposure is conspicuous by its dark colour. In the dark sand up to 25 pCi/g 238u or 232>rh have been measured as shown e.g. in table 1. In the dark sand the heavy minerals are enriched. In the main, the dark sand consists of silicon, titanium, iron, aluminum, zirconium etc.. Only little monazite has been found. Uranium and Thorium are mixed witb the zirconium. The enrichment of heavy grains with high neavy mineral concentrations results from the movement of the grains due to the influence of water and wind. The grains originate from granite stones which moved at glacier time from Scandinavia to the North Sea. Places with enhanced gamma radiation exposure have been found at the coast of different East- and North-Fri- sian Islands. However, these places are not as extensive as e.g. those at the coast of Kerala. The highest measured local dose rate is 5oo mrem/a. If the regions would be larger, local dose rates up to approximately 1ooo mrem/a might occur.

••* P na REFERENCES

1. Bonka, H. : Erhöhte natürliche Strahlenexposition dur-- Schwermineralanreicherung an der Kuste Ivcrddeutschlancs Atomkernenergie - Kerntechnik 35 (198o):5 2. Bonka, H. : Erhöhte terrestrische Strahlunu durch Schwermineralanreicherung an der Kilste der Insein Norddeutschlands; Seminar on the radiological burden of man from natural radioactivity in the Countries of the European Communi- ty, 4-6 Dec. 1979, Le Vesinet (in print)

250 iwrwn a 150 h 100 A \\ 50 4 u 0 \

Shiwwefc lOmtm/a North S*o

lMi£it: 350mrtm/o at surface: SOOimtn/a

o tooipoeon tywoom

rig, ii Arc* ultli «flhAncKl local do«« rat* du* to t«rr«atrlc tadlatton at th« coatt of th« laland Horovmay ae CM North Saa

Activity [pCi/g] No. Island Date Conment U 238 Th 232 1 Nocdamy 2.10.78 0,2 0,15 Light non»! «and at tra ooaat of Fadanl *puhUc of Oanany; K 40-*Ktlvtey: Sp!l/g 2 2.1O.7B 19 1.1 Dark aard, fint auatd* 1 Nixdacmy 21.10.7» 20 22 Dark land of location with tuqhaat radiation «foaura in Fig. 1

4 sylt 2.12.7a 1« 20 Dark sand of tra wast bsach naar tra ton Hoama 5 s,lt 24.09.7» 10 24 Sard of a nasxly 1 cat thick dark layar (m th* batch of tha tan Haatarlard « Julat 20.10.79 » S Dark sard naar tha vastrolnt of tha laUrd 7 Wngunqa 17.10.7» e Dark aand Ira th» bsaeh of tha ton W»javuJja

Tab. Is IHaaiiiail acUvltlM lr. diffanrtt aand aasplas at Islands of U* Vtdsral Bapublic of Qarsany II 4

BACKGROUND LEVELS OF NATURALLY OCCURRING RADIONUCLIDES IN ENVIRONMENTAL SAMPLES TAKEN FROM A URANIUM ORE RICH AREA OF NORTHERN SASKATCHEWAN, CANADA

J. R. DEAN, N. CHIU, P. NEAME; MONENCO CONSULTANTS LTD. CALGARY, ALBERTA, CANADA. J. BLAND; UNIVERSITY OF CALGARY, CALGARY, ALBERTA, CANADA.

The most abundant naturally occurring isotope of Uranium, Uranium 238, decays into many long-lived alpha and beta particle emitters such as Radium 226 and Lead 210. It is feared that biological consequences may be observed if significant concentrations of these daughters find their way into the food chain of humans. One pathway is via the well documented Radon 222 emanation mechanism which can allow Lead 210 and Polonium 210 to accummulate on the surface of the earth. The effect of Uranium strip mining on this phenomena and on the entrance of other nuclides into the food chain is of considerable importance. A study carried out in a Uranium rich mining area of Northern Saskatchewan, Canada, revealed interesting data concerning activity levels of Uranium 238 daughters in the natural environment. Samples of water, suspended particulate matter, benthos, sediments, terrestrial vegetation, aquatic vegetation, small mammals and fish were analysed for Uranium, gross alpha, gross beta, Radium 226, Polonium 210, Thorium 228, Thorium 230 and Lead 210 activity contents. The predominant contributor to the alpha and beta activity of the samples was found to be unsupported Lead 210 and its daughters Bismuth 210, and Polonium 210. For the sediments, evidence is presented to suggest that the source of Lead 210 is via a Radon emanation mechanism. The levels of Lead 210 and Uranium in sediments were found to vary directly with the organic carbon content. In most samples, the Lead 210 activity levels were at least an order of magnitude larger than expected from the Uranium contents. The average level of Lead 210 in the terrestrial vegetation was 4.7 pCi/g. This accounted for the predominant portion of the beta activity and compared with a Radium 226 content of 0.14 pCi/g. The Lead 210 activity level variations as a function of individual plant species are discussed. Lichen, for example, were found to contain the highest average levels

'• n <=.- of 11 pCi/g. The Polonium 210/Lead 210 ratio '..as io_.iu to vjry with the growth behaviour of individual species. A.c-jn^i,.]aticns of Radium 226, Thorium 230 and Thorium 228 were noc found in the terrestrial vegetation. The aquatic vegetation contained 10-20 tirr.es higher levels of Thorium 228, Thorium 230 and Radium 226. However, the Lead 210 levels were lower. The subnergents, PotarajJ2,

INTERNAL DOSIMETRY OF RAOON-222, RADON-220 AND THEIR SHORT-LIVED DAUGHTERS

W. Jacobi, K. Eisfeid

GSF, Institut fur Strahlenschutz Mlinchen -Neuherberg, BR Deutschland GSF-Report S-626, Jnauary 1980

In this study the results of a sensitivity analysis are described which shows the influence of relevant physical and biological parameters on the dose from inhaled Rn-222, Rn-220 and their daughters to the basal cell layer of the bronchi, to the pulmonary tissues and to other body tissues. The used models for deposition, retention and dosimetry of inhaled daughters take into regard the variation of following parameters: The AMAD of inhaled radioactive particles; the fraction of unattached daughters atoms; the velocity of ciliary transport; the desorption rate of attached daughter atoms from their particles; the absorption rate to blood; and the depth of the basal cell layer in the bronchial generations. A computer programme was set-up for the calculation of the activity and dose distribution in the lungs as function of these parameters. For the evaluation of the effective dose from inhaled mixtures of Rn-222- and Rn-220 -daughters three different alternatives for the weight- ing of the mean doses to the target tissues in the lungs are described, taking into regard possible differences between the cancerogenic sensitivity of the target cells in the bronchial and alveolar region. On the basis of the results of this sensitivity analysis mean values for the effective dose to adults per unit of inhaled potential a-energy (in Joule) and per unit of potential a-energy (in WLM) of daughters mixtures are derived as function of the unattached fraction of potential a-energy in air and the desorption half-life time of attached daughter atoms in the lungs. In addition the effective dose from inhaled Rn-222 and Rn-220 (+ Po-216) and from ingested Radon and its daughters is estimated. Finally the consequences for the assessment of intake and exposure limits for workers and for members of the public are outlined. Ill '/.

COMPARATIVE DISTRIBUTION OF THORIUM, URANIUM AND PLUTONIUM IN HUMAN TISSUES OF THE GENERAL POPULATION Narayani P. Singh and McDonald E. Wrenn Radiobiology Division, College of Medicine, University of Utah Salt Lake City, Utah 84112 Earlier studies on thorium concentration in human tissues are scattered and inadequate to reconstruct the metabolic pattern of thorium in man. For example, Hill (l) reported a concentration range of 0.2-1 pCi/kg wet weight for Th-232 in nine lungs with uncertainty of spectral interference from Th-230. Petrow and Streh'ow (2) found 10 ng of thorium per gm of bone ash of composite sample of skeleton of several adults. Picer and Strohl (3) reported a value of 23 ng of Th-232/gm of bone ash for an individual of unknown age. Lucas (4) in his detailed work found a thorium concentration of 0.1-72 ng/g ash in 38 rib bones of humans. Clifton et al (5) reported the concentration of Th-232 in persons from the United Kingdom to vary from 0.8-164 ng/g of bone ash with a mean of 28.7±13-1 ng/g.

A systematic study was done by us where sets of human tissues including lung, lymphnodes, liver, bone, kidney and spleen were analyzed for Th-228, Th-230 and Th-232 from Grand Junction, Colorado (22 sets) and from Washington, D.C. (10 sets). The results are as follows: Isotope Locat ion Order of Decreasing Concentration Th-228 Grand Junction Lymphnodes>bone>1ung>k i dney>liver Washington, D.C Lymphnodes>bone>lung>kidney>!iver Th-230 Grand Junction Lymphnodes>bone>1ung>k i dney>1iver Washington, D.C Lymphnodes>bone>1ung>1i ver>k i dney Th-232 Grand Junction Lymphnodes>lung>bone>k?dney>lfver Washington, D.C Lymphnodes>lung>bone>liver>kidney Very limited information is available on the concentration of uranium in human tissues and none on the isotopic concentration of U-238 and U-234. Welford et al. (7,8) reported the average concentration of 20 and 3-2 ng of uranium/gm of bone ash, 0.13 ng/g of liver, 0.24 ng/g of kidney, 0.57 ng/g of blood and 0.53 ng/g and 1 ng/g of wet lung. Hamilton (9) found average concentratiaons of 0.16 ng uranium per gm of heart, 0.25 ng/gm of liver, 0.84 ng/g of blood, 0.60 ng/g of fat, 0.19 ng/g of muscle and 6.96 ng/g skeleton. Nozoki et al. (10) analyzed 47 samples of bone and found an average concentration of 2.0 ng/g wet bone. Ganguly (11) reported a concentration range of 2.3-3.4 ng/g wet bone and 0.6-3-8 ng/g wet kidney from Bombay, India.

Ten sets of human tissues including lung, lymphnodes, bone, liver, kidney and spleen are being analyzed inour laboratory for isotopic concentrations of U-234 and U-238 from the Colorado (USA) area and the results will be included in our final paper. Plutonium has been studied very systematically by different groups in the United States and other countries. Results of Mclnroy et al (12), Wrenn et at. (13) and Mussaio et al. (14) in terms of organ distribution is similar and Is given below: Lymphnodes>1iver>bone>lung>sp1een>kidney Data from Japan (15,16) is limited and no clear cut distribution pattern can be drawn. Limited data onPu-239,240 concentrations in lung and lymphnodes are available from the Soviet Union (17). The lymphnodes contained 7-9 pCi/kg and lung contained 0.11-0.15 pCi/kg.

The summarized organ distribution pattern of thorium, uranium find plutonium are given In Figures 1 and 2. Lymphnodes concentrate the highest amount of thorium and plutonium whereas there is inadequate information available about uranium. The major difference between the accumulation of three actinides is in liver; plutonium is mostly concentrated in liver whereas thorium and uranium are least concentrated in liver. This is very unique in the sense that thorium and plutonium, being most similar* chemically and biologically, should have behaved similarly but, in fact, thorium behaved more like uranium.

Lung contained the highest amount of Th-230 and 232 following lymphnodes. Uranium was elevated in lung which probably suggests that accumulation by inhalation Is not negligible relative to ingestion for accumulation of uranium in the human body. Plutonium was higher in lung in the early 60's, but as time passed, the air concentration of fallout plutonium decreased drastically and therefore lung burden decreased due to trans location of plutonium to other organs.

The concentration of Th-228 was highest in bone, following lymphnodes which may have been due to intake of Ra-228 parent and its subsequent decay to Th-228. The concentrations of Th-230 and Th-232 were higher than all other organs except lymphnodes and lung. According to several authors, bone seems to have the highest concentrations of uranium; however, the revised results reported by Wel ford et al. (18) give very low concentrations (0.11 pCi/kg), in fact, lower than lung. An ideal comparison of the organ distribution pattern of three actinides can be achieved by determining thorium, uranium and plutonium in each organ of the same subject simultaneously. We have determined the concentration of thorium and plutonium simultaneously in the tissues of same subjects and the results are in agreement with the results summarized earlier (18,19). SELECTED REFERENCES ( 1). Hill, O.R., Health Phys. 8:17 (1962). ( k). Lucas, H.F. et al., Health Phys. 19:739 (1970). ( 6). Wrenn, M.E., Singh, N.P. et al., NRC Rept. Nureg/CR-1227 (1980). ( 7). Welforc, G.A. and Ruth, B., Health Phys. 13:1321 (1967). ( 9). Hamilton, E.I., Health Phys., 22:149 (1971). (12). Mclnroy, J.F. et al., Health Phys. 37:1 (1979). (18). Singh, N.P. el al., Health Phys. Abstr. P/101 (1979). (19). Singh, N.P. et al., Health Phys. Abstr. P/91» (1978) Th-228, 230 AND 232 IN HUMAN TISSUES OF WASHINGTON D.C. (Non-occupational) io.Oq 8,0; Th -228 6.0- Th-230 Th-232 4.0-

2.0-

:i i.o a 0.8 0.6-

0.4- 0.2- J LUNG LYMPH LIVER BONE KIDNEY NODES

Th-228, 230 AND 232 IN HUMAN TISSUES OF COLORADO (Non occupational) 20.0-

Th-228 10.0- Th-230 : 8.0 P Th-232 6.0- 4.0-

2.0-

0.6- 0.4-

0.2-

0.1 J LUNG LYMPH LIVER BONE KIDNEY SPLEEN NODES

FIG. 1 URANIUM IN HUMAN TISSUE

E'S Weiford USA 20- Hamilton UK Nozoki V////1 Ganguli 1.0- 0.8- 5* 0.6- "g i3 o a 0.4-

0.3- o 0.2- f= ö 1 0.1 LUNG LIVER . BONE! KIDNEY

Pu 239, 240 IN HUMAN TISSUES (Non Occupational)

NYU (Wash.D.C.) (Colorado) (Penn) FINLAND

LUNG LYMPH LIVER BONE KIDNEY SPLEEN1

FIG. 2 - 16 - HATOHAL RADICKCTIVITT Iff THE MAEI5E miHOTMBÏf

L.Ü. Joshi Air Monitoring Section Bhabna Atomic Beaearch Centre Trombay, Bombay-400 085 and S»Z. Qaeim National Institute of Oceanography Dona Paula Soa-403 004

The naturally occurring radionuclides are always present in uea water and in aarine organise and sediments. However, the concentration of radionuclides in the ocean jiffars from that of The earth's crust as in the oceans the radionuclidec are introduced by land run-offs as products of erosion and also as a result of precipitation from the atmosphere. Measurements of natural radioactivity due to thorium, ur^niurr, radium, protactinium etc.? have been carried out in coastal ^edixents and in se& water of the weet coast of India. These investigations were carried out with a view to understand tae distribution of the labile component of natural radioactivity in the narine sediments and waters. The sediment samples were leached with b% 3DTA far the extraction of thorium and radium. Uranium is extracted from the surface of the sediments by leaching with saturated solution of ammonium carbonate and protactinium is leached with IÜ oxalic acid. The separation of the ü, Th, Ra and B» is carried cut by ion-exchange methods and the radioactivity due to Th2-72, Tfa23<-, Th22e, U23~, U2-5', y , 23 228 231 TJ234, Ra228 ^ Ra231, is.measured in the samplee = BXi 232 2?fl It has been observed that dis-equilibrium between Th and Th as well as U233 and TJ234 exists only on the surface labile layer and when the labile component is removed, the core shows equilibrium activity. The concentration factors of Ea as well as fe have also been calculated. Cn the basis of the values obtained for Ba228 concentration in waters and the concentration of Ra228 in the organic layer, the calculated concentration factors range from 20,000 to 50,000. In the case of Ra231, the concentration factor for B&231 in the organic layers ia calculated to be 4.7 x 106. The thickness of the labile organic layer on the sediment particles has also been calculated and this is found to be in the range of 2.5 x 10~° cm to 10.0 x 10"^ cm. These values are comparable to the values obtained bj the electron microscopy method. 11 I-A 1

Some Aspects of Radon and Daughter-Products in Man and His Environment

J. Rundo, F. Markun, N. J. Plondke and J. Y. Sha Center for Human Radiobiology, Argonne National Laboratory 9700 S. Cass Avenue Argonne, H 60439, U.S.A.

Our observation of a transient postprandial increase by a factor of about two in the rate of exhalation of radon produced from radium in the human skeleton, led us to seek a similar increase in the exhalation of radon which had been inhaled previously. We knew that the concentrations of radon in many houses were appreciably higher than in our laboratories. The inhalation of radon in the home results in a body content of the gas because of its dissolution in body fluids and fat. When a person leaves the house his content is reduced by exhalation if the airborne concentration of radon is lower in the new environment.

We have made serial determinations of the exhalation rate of radon of seven subjects who ate breakfast after their arrival in our laboratory. In all cases the expected decrease in exhalation rate was interrupted by a marked postprandial increase, of some two to three hours' duration. At the time of the maximum, the ra'te was about twice what would have been expected had there t-en no increase. The results will be presented in detail.

The airborne concentrations of radon in the six residences of the seven subjects were determined as part of the study Just described. Five values were less than 5 pCifl, but the sixth house contained about 26 pCi/£ the first time it was sampled, and 12 pCi/fl. on a second sampling three months

- "a - later. On investigation we discovered that the radon was entering the nous--:

by emanation from the ground in the unpaved crawl space. We deter mire "'

the radon concentration in the air of 21 other houses, all of wooden f ram.. construction, and all having unpaved crawl spa-jes. Nine of the 22 houses showed levels in excess of 5 pCi/£, and in six of therr: the concentrations (2) exceeded 10 pCi/£. At the same time we also observed a concentration in one house as iow as .0.3 pCi/5.. Measurements were also made of the concentrations of the short-lived radon daughters, 218Po, 21Tb and 21''B;, with an Environmental Working Level Monitor (3) in the first house ir. which we had observed the high levels. The mean for three periods each lasting

92-113 hours was 0.018 WL. Details of these and other measurements will be presented.

The repeated observation of high levels of radon and its daughters in this house raised the question as to whether the occupants might contain sufficient amounts of the short-lived daughters to be detectable by external counting. On separate occasions we have made serial measurements of thp radioactivity in the three residents of the house, i.e. the husband and wife and their baby. The results for the baby indicated clearly the presence of

21<(Bi but at much lower levels than the easily measurable ones found in the adults. In each subject, the content decreased rapidly at first and then much more slowly. We interpreted the rapid decline as a reflection of the decay of radon daughters in the lung, unsupported by the parent radon, while the long-term component was attributed to radon daughters distributed throughout the body, and supported by radon dissolved in body fluids and fat. The best estimates that we could make of the contents were 9.5 nCl and 12.7 nCl for

the short-term exponents In the man and his wife respectively, and 2.2 nCl

and 5.1 nCi for the long-term components respectively. With certain assumptions,

we calculated absorbed dose-rates of 2.4 rad/yr and 4 rad/yr to the lungs of the male and female subjects, respectively.

Finally, the presence of easily measurable radon daughters in the lungs can have important consequences In radiological protection, because of their possible mlsidentification as uranium L x rays emitted by plutonium.

References

1. Rurido, J., Markun, F. and Sha, J. Y. "Postprandial Changes In the Exhalation Rate of Radon Produced in vivo," Science, 199, 1*211-1212 (1978).

2. Rundo, J., Markun, F. and Plondké, N. J. "Observation of High Concentrations of Radon in Certain Houses," Health Phys., 36, 729-730 (1979).

3. Keefe, Do J., McDowell, W. P. and Groer, P. G. "The Environmental Working Level Monitor," U.S. Environmental Protection Agency Report No. P7628C, U.S.E.P.A., Washington, D. C. (1978).

20 JII-A 2

THE VARIATION OP SATURAL BACKGROUND RADIATION IS THE FEDERAL REHJBLIC OP GERÜAHY.

H. Schmier Institute fcar Radiation Hygiene, Federal Health Office, Ingolstadter Iandstr. 1, 6042 Neuherberg/ttuaieh, Federal Republic of Germany

Within + he framework of a research project supported by the Federal Minister of the Interior, 30,000 measurements were conducted with scintillation dosimeters of the same type in 10 institutions distributed all over the Federal Republic of Germany, determining the local rate of gamma radiation in buildings (mean values). In addition, 25,000 measurements of the local dose rate of gamna radiation in the free environment as well as approximately 6C0 measurements were performed via gamma spectroscopy of the specific content of natural radioactive substances in building materials. The dose rate measurements were centrally evaluated by an electronic data processing system, whereby the following aspects were taken into consideration : regional differences, differences depending on age and type of buildings, differences depending on the content of natural radioactive substances in building materials. The results of the research program will be announced- Temporal Variations of the Natural Radiation Field

Harold L. Beck Environmental Measurements Laboratory New York, N.Y.

Data obtained from continuously monitoring high pressure ionization chambers (PIC) at a number of sites in the N. E. United States have been used to study the temporal variations of typical external natural radiation fields. Besides providing highly precise information on the monthly and seasonal variations in the total penetrating exposure, these data also provide a statistical profile of the shorter term fluctuations caused by washout and rainout of radon daughters. When supplemented by other measurements, including soil moisture, precipitation rates, and barometric pressure, the PIC data provide a com- prehensive picture of the magnitude and frequency of the various contributors to temporal variations in the open field exposure rate.

Annual free-air exposures of 0.5-1.0 mR from radon daughter washout were measured at one site over a two year period. These increment- al exposures are of the same order as those expected near the fenceline from routine gaseous releases from nuclear power plants and can thus complicate the accurate measurement of such manmade perturbations. Changes in soil moisture and snow cover have a much larger effect on natural radiation levels with month to month fluctuations greater than ± 20% not uncommon.

The cosmic ray component of the natural radiation field also varies with time. Short term fluctuations occur due to variations in atmospheric pressure and temperature. Longer term variations occur due to periodic changes in solar activity.

Finally, diurnal an* seasonal variations in radon exhalation and atmospheric turbulent diffusion cause large perturbations in the external exposure rate from airborne radon daughters, although this usually results in only small perturbations in the total exposure rate,

Other data in the literature on temporal variations are also reviewed as well as the predictions of mathematical models of external radiation fields. I .TT> i_i

NATURAL RADIATION QUALITY OF THE ENVIRONMENT IN THE UNITED STATES

Raymond H. Johnson, Jr., Neal S. Nelson, Abraham S. Goldin (.U.S. Environmental Protection Agency, Office of Radiation Programs (ANR-461), 401 M St., S.W., Washington, D.C. 20460) and Thomas F. Gesell (University of Texas Health Science Center at Houston, P.O. Box 20186, Houston, Texas 77025)

The U.S. Environmental Protection Agency (EPA) has gathered data for many years on the radiological quality of the environment in the United States. The contribution of natural radiation to overall exposures is becoming of increasing concern to EPA, especially those exposures influenced by man's activities (technologically enhanced natural radiation). EPA is revising estimates of background radiation from cosmic, radiation and terrestrial radiation to account for the influence of shielding by construction materials and self absorption by body tissues. The revised average external whole body dose is-28 mrem/year for cosmic radiation and 26 mrera/yr for terrestrial for a total of 54 mrem/yr. This is a reduction of 23 percent from the previous estimate of 71 mrem/yr. The internal contribution of potassium-40 (19 mrem/yr) and elements of the uranium and thorium series bring the total background dose equivalent to about 75 mrem/yr.

Data will be presented on EPA studies of technologically enhanced radiation sources including ore mining and milling (uranium, phosphate, iron, copper, zinc, clay, limestone, fluorspar, and bauxite) fossil fuel combustion, radon in water, geothermal power, construction materials, and indoor radon. The data will include radionuclide release rates for each source category and the resulting internal and external dose equivalents to individuals and the population. The calculated doses will be related to health effects and health risk except for the short-lived radon daughters. For these nuclides, the health risk estimates will be related to exposures in terms of working levels. Dose data will also be presented on other sources of ambient ionizing radiation such as tritium, carbon-14, krypton-85 and actinides.

23 III-A 5

POLOHIUM IV THE COASTAL WATERS AT KALPAKKA*

M.A.B. Iyengar, V. Xannan, S* Ganapathy and P.B. Kanath E.S. laboratory Salpakkaa, Xaallnadu 603102

The occurrence of patches of aonazite in the beach sand at Kalpakkam led to the present investigations of leached alpha activity in filamentous weeds and edible tissues of marine organisms in coastal waters* Distribution of Ba in the marine environment at Ealpakkam was reported in the NBE Symposium held in 1978. Ra-226, Ba-228 and Ba-D and its daughters are present in sea waters as a result of decay of Th and U present in monazite. The radiums and lead isotopes concentrate in skeletal tissues of fishes and are not at as much concern as the radioelementa that concentrate in edible tissues. Polonium is a short lived alpha emitter from Ba-Z) decay which is ubiquitously present in the coastal waters, weeds and organisms* The beaches are frequented by fishing families, fishing being an Important activity of the people. The fish intake by fishermen on the average works to 120 g/day. A large number of environmental samples were collected in the coastal waters for Po content. The samples examined are - sea water, sea silt» salt, pelagic fishes, benthic organisms and intertidal biota-mollusca, Crustacea and macrophyta. Po distribution is reported in fish-soft tissue, gills, liver, viscera and bones and shell. Cybium has shown liver Po concentration of 580 Bq Kg activity and a CF of 2.7 x 10^. In the crabs haepatopancreas has a high CF (6*9 x 10*). These C? values are comparable to CP in silt* Methodology of determination of Po is of interest because of loss of Po in different analytical steps. Separation techniques in large volumes of water and standardisation procedures are described. The significance of Po concentration in edible fish tissue is discussed in relevance to human exposures. KttCCUMULATIOT CF RADIUM IH AN AQUATIC ECOSTSTïM

P.M. Markose, £.P. Eappen, M. Raghavayya and B. Fatel Bbabha Atomic Research Centre Health Physics Unit Jaduguda, Bihar

'Sadium1 the most hazardous radionuclide encountered in the mining and milling of uranium ore is mostly contained in the tailings pile. A part of this escapes into the environment from the containment system by means of dissolution and bioderradation. This fraction, though small in quantity may ultimately be taken up by the population and thus pose an environmental problem. Constant surveillance of the environment receiving the effluents from raining and milling operations is therefore necessary for the control of population dose arising out of exposure to this enhanced radiation. Information regarding the accumulation pattern of the radionuclide in aquatic organisms is one of the essential parameters in this respect. In view of this, some aspects of the accumulation of radium in a few organisms of significance in the aquatic environment of the uranium mining complex in India were studied. The results are presented and discussed in this paper. The uptake of radium by algae, gastropods and fish was investigated in the laboratory under simulated conditions as -well as under actual environmental conditions. The major source of population exposure is through gastropods and fish, but considering the distribution in edible and nonedible (shell and bone) tissues, the dose to the population is probably not very significant. Accumulation of radium in different size groups of Ophiocephalus sp which survive in the effluent carrying stream was studied. The increase in radium content of the tissue has been observed to be a function of the weight of the tissue. The ratio of radium in edible soft tissue to that in bone was found to be approximately 1:6. The concentration factors with respect to the ambient radium concentration in the stream has been found to be between 5 to 15 in flesh and between 40 to 75 in bones. The snail 7iviparuB bengalensis was observed to accumulate radium rapidly, reaching equilibrium in about 24 hours. The rate of uptake of radium in the tissue of the species was observed to be high. However the biological half life of the radionuclide in the edible tissue of the species has been found to be short. Two sets of experiments - one in the laboratory under controlled conditions and another under field conditions were conducted. Under the two conditions the species showed two different uptake/release patterns suggesting that the reactions

25 of an organism to a coatrolled set of conditions may be different from that to the natural environment. The tissue of snails showed a maximum concentration of 2900 pCi/Kg (117«3 Bq/Kg) and shell about 5500 pCi/Kg (203.5 Bq/Kg). It is also indicated that the level of calcium in the media has a direct bearing on the accumulation of radium in the species. Analysis of samples of Spirogyra spp. unicellular algae, collected at various locations in the streams indicate that there exists a good correlation (correlation coefficient 0.96) between the concentration of radium in the medium and that in the species. The concentration factors varied from 800 to 3100 with a mean of approximately 2000» The species» therefore, may be used as a 'quantitative indicator organism' for the probable level of radium in the aquatic system. Ill--,

THORIUM CONTENT OF HUMAN TlSsüÉJ .-.

Age, sex, occupation, and smoking history was recorded as well as results of pathological examination of tissues. Evidence of tumor or carcin- nomas, organ degeneration, and the cause of death were determined. Tracheo- bronchial lymphnodes were dissected from the lung by a trained technician.

Analytical Technique. Thorium in soft tissues and bone was determined by radiochemical procedures (1,2) involving wet ashing, solvent extraction and a-spectrometry using Th-229 as an internal tracer (3). Results. The two populations were not well matched by age, sex, occupation and smoking history. The G.J. subjects were older (median age 67 vs 33 years), smoked less heavily (50? vs 80%), and contained a greater proportion of males (771 vs 60%). The age distribution is particularly import- and because the concentration of thorium in bone is known to increase with age (Lucas).

The median concentrations of the Th isotopes in tissues from both populations are shown in Table 2, and the tissue concentrations are ranked as follows: 1sotope Location Order of Decreasing Concentration Th-228 Grand Junction Lymphnodes>bone>?ung>kidney>J iver Washington, D.C. Lymphnodes>bone>1ung>kidney>liver Th-230 Grand Junction Lymphnodes>bone>1ung>k i dney>1i ver Washington, D.C. Lymphnodes>bone>1ung>1iver>k i dney Th-232 Grand Junction Lymphr.odss>l ung>bone>kf dney>l iVer Washington, D.C. Lymphnodes>lung>bone>liver>kidney

~ 2? The median Th-230 and Th-232 in G.J. tissues exceeded the Wash., D.C. Use of the Wilcoxon Rank sum test suggests that Th-230 and Th-232 in lung, lymphnodes, kidney, and bone in G.J. differ significantly from Washington, D.C. The median concentration of Th-230 and Th-232 in the lunj, lymphnodes, kidney, and bone of G.J. subjects exceeded those of Washington, D.C.

One likely reason is that the different age distribution of the two groups. The median ages-were 67 (G.J.) and 33 years (Wash., D.C.). Since Th-232 and Th-230 increase with age in bone, a higher concentration of both isotopes was expected in the G.J. subjects. For comparison, Washing- ton, O.C. subjects had a median age of 33 and a median concentration of 0.32 pCi/kg, and 0.10 pCi/kg for Th-230 and Th-232 in bone, respectively. If the concentration in b-one is extrapolated in a linear fashion to that expected at 67 years (the median age for G.J. subjects), a median concentration in bone of 0.6^ and 0.2 pCi/kg for Th-230 and Th-232 would be expected. As shown in Table 1, this estimate is comparable to that of Th-232 obtained from G.J. bones (0.19 pCi/kg) and slightly less for Th-230 (0.92 pCi/kg).

The ratio of Th-230/Th-232 should be independent of biological variations between individuals, and should be age-independent, but will depend on the source of the exposure. The Wilcoxon Rank Sum Test, performed using the Th-230/Th-232 concentration ratios for the individuals of the two groups, showed no significant difference in this ratio between the two groups in any tissue except in bone (P<0.l). Because the skeleton accumulates thorium throughout life, and the lung and lymphnodes reflect more recent exposures, the elevated ratio of Th-230/Th-232 observed in the skeleton (but not lungs) of the G.J. subjects may have been caused by past exposures to a source elevated in Th-230.

Another possibility for the elevated Th-230/Th-232 ratio is that un- identified occupational exposure cases could have been included among the G.J. subjects. General conclusions are (1) the 3 to 6-fold greater Th-228 in bone compared to 232 suggests the Ra-228 parent is the source of most Th-228 in bone from ingest ion, and (2) most of the Th is in the skeleton at the end of life.

REFERENCES 1. N. Singh, S. Ibrahim, N. Cohen, and E. Wrenn, Anal. Chem. 51:207 (1979). 2. N. Singh, S. Ibrahim, N. Cohen and £. Wrenn, Anal. Chem. 51:12 (1979). 3. E. Wrenn, N. Singh, S. Ibrahim, and N. Cohen, Anal. Chem. 50:1712 (1978). TABLE 1

Concentrat ion in pCi/kg Grand Junction Washington, D.C. Organ Isotope Median Age 67 y Median Age 33 y Age Adj. at 67 y

Bone Th-230 0.92 0.32 0.65

Bone Th-232 0.19 0.10 0.20

TABLE 2 MEDIAN CONCENTRATION OF TH-228, 230 AND 232 IN TISSUES OF GRAND JUNCTION, COLORADO AND WASHINGTON, D.C. SUBJECTS (pCiAg Wet Weight)

GRAND JUNCTION Lung Lymphnodes Liver Bone Kidney Spleen Th 223 0.28(20)* 5.1(14) 0.07(16) 0.54(16) 0.07(17) 0.06(14) Th-230 0.80(19) 11.0(14) 0.15(16) 0.92(17) 0.29(17) 0.13(14) Th-232 0.58(19) 7.8(14) 0.03(16) 0.19(16) 0.07(16) 0.09(14)

WASHINGTON, D.C. Lung Lymphnodes Liver Bone Kidney Th-228 0.24(10) 2.6(10) 0.09(10) 0.66(7) 0.09(8) Th-230 0.36(10) 4.6(10) 0.11(10) 0.32(7) 0.17(8) Th-232 0.32(10) 2.8(10) 0.05(10) 0.10(7) 0.03(8)

•Numbers in parenthesis present the number of samples analyzed*

- 29 - • Ti.l -A 3

210Pb- 210Po-T00TH CONTENT AND RADOH DAUGHTER EXPOSURE

G. F. Clemente, A. Renzetti, and G. Santori, CNEN, Roma, Italy J. Pohl-Rüling and F. Steinhausler Division of Biophysics, University of Salzburg A-5020 Salzburg / Austria

It has been demonstrated that the Pb- Po-skeletal burden in miners (uranium and non-uranium) and spa workers can be heavily increased by the prolonged exposure to high levels of radon daughter air concentration (1). The 21 Opt,- Ôpo-content in tooth samples may then be considered a good index of the skeletal burden due to these radionuclides and therefore of the past integrated exposure to radon daughters. To establish the reliability of this hypothesis the 21^Pb- 210Po- content has been measured in 60 tooth samples collected from 57 individuals of varying ages, exposed to different levels of radon daughter exposure. Most of the persons considered have been living and working in the Austrian Badgastein spa area. Also included in the test population was a low-exposure group, represented by residents in other parts of the Gastein valley or by persons who stayed in Badgastein only for short periods. Badgastein is a well-known spa, over 600 years old and situated in the Central Alps (population; 65OO inhabitants). The main contribution to the elevated natural radioactive environment results from the 19 thermal springs in the center of the town, supplying daily more than 5 x 10" liters water (temperature up to U8°C) with a mean 222Rn concentration of kO nCi/liter. Annually about 58 Ci of radon diffuse from the water into the open air at the spring-heads and reservoirs, respectively into the room air from th« baths at the about 120 hotels. During the past 30 years many thousand measurements of the atmospheric concentration of 222RQ, ssO^ as wen as their short- and long-lived daughter products have been carried out indoors and outdoors. Based on these nuclide measurements and our calculations regarding the dose distribution in the human body (2, 3, M, the past radon and daughter exposure levels have been assessed for each individual separately. The data related to the Badgastein persons will be compared to the 210pb^ 210po_content measured in tooth samples collected from members of the general Italian population. The method applied to determine Po in the tooths samples is based on a coprecipitation of polonium with manganese dioxide after wet ashing of the sample (5). The 210po plated on silver disk is then measured by solid state detector alpha spectrometry. Owing to the very long time elapsed between sample collection and analysis the equilibrium condition can be assumed for 210pb gâ 210p0 jn tê analyzed sample. There- fore 210po only has been measured in all samples. The 210pb_ ^'^rPcfBkeletal dose will be evaluated for all subjects under the assumption that the bone 210pb_ 210p0_conceQtration is similar to that found in teeth. References; (1) G. F. CLEMENTE, A. RENZETTI, G. SANTORI, and F. BREUER, Assessment of 210po exposure for the Italian population, Proc. of the Vth IRPA Int. Conf., Vol. Ill, 303-306, 1980 (2) J. P0HL-3ÜLING and F. SCHEMINZKY, The natural radiation environment of Badgastein, Austria and its biological effects, Proc. Sec. Symp. Hat. Rad. En?., CONF - 720Ö05 - Pi, 393, 1972 (3) E. POHL and J. POHL-RÜLING, Dose calculations due to the inhalation of Rn 222, Rn 220 and their daughters, Health Phys. 32, 5521 1977, {k) W. HOFMANM, F. STEINHAUSLER, and E. POHL, Dose calculations for the respiratory tract froc' 'nhaled natural radioactive nuclides as a function of age - pavt I: compartmental deposition, Health Phys. 37, 517, 1979, (5) G. F. CLEMENTE, A. RENZETTÏ, G. SAKTORI, and A. K. BACHVAROVA, Valutazione delle esposisione da 210pD_ 210p0 nella popula- zione italiana, CNEN Tech. Report RT/PROT (79) 6, 1979. Ill—A 9

Analysis of human teeth for ^?b aud °Po

A.TÓTH, J.PETER, J.3ZABÓ and I .BERTA Hospital-Clinic of Baranya County, Low Level Counting Laboratory,H-7633,Pecs,Dr.Veress E.u.2. and Medical University Pecs, Dental Clinic, H-7623,Pécs,Dischka u.5« Hungary

Analysis of the 210 Pb-content of easily accessible and in great number avaiable extracted human teeth may be suggested to provide indirect information on the 210 Pb- content of the skeleton or on the surplus 210 Pb-content of the skeletal bone system induced by smoking and perhaps on the cumulative radon daughter exposure of miners* Extracted teeth were collected from coal miners and from individuals not engaged in mines /that is from control persons/* Smokers and non-smokers were evaluated separately. The following data were registered: age, sex, place of residence, working place, occupation, duration of the job, the number of teeth extracted, their localization and whether the teeth were still living or greatly devitalized, the length of the smoking period and the number of cigarettes smoked per day. Prior to the analysis the fillings and the debris of the teeth were removed as well as the wet mass and the Ca- content of the teeth had been determined. In 37 measurement a proportion of 0,3 of Ca mass per wet mass was found. Even the 210 Pb-content of a single tooth can be determined by the method of Radford et al. /1963/ as well as by our scintillation alpha counter which has a counting efficiency of 30 percent and a mean background measured by net nickel plates of 1 impulse pro hour. Por a 10 hours measurement period and a wet tooth mass of 1 gram, the minimal measurable 210 Po-content in the teeth was found to be 0,6 mBq. pro gram /i.e. 0,02 pCi per g/ as calculated by the twofold counting error of the sample counting rate. Determinations in 140 samples performed so far revealed higher contents of 210 Po than the minimal measurable limit mentiond above. The frequency distribution of the 210 Pb- and 210 Po- contents for all the teeth samples /coal miners, controls, smokers and non-smokers, males and females/ appeared to be log-normal as shown by the straight line for data

32 - plotted on log-probability paper. Significant differences were found between the 210 Pb- contents of non-smoker coal miners and non-smoker control males. In smokers on the other hand the surplus 210 Pb-content, induced by smoking, masked tae difference. In the group of the control males there was a higher 210 Pb- and 210 Po-content in the teeth of smokers than that of non-smokers. The 210 Po-content of the teeth appeared to be related to the age of the individuals showing a catenary-like curve. Greater activities being shown under 20. years of age as well as over 50. years time of life and smaller contents between 20. and 50. years. A possible explanation of this finding may be that the 210 Pb can get into the teeth by two different ways. Partly fron the blood stream, being active particularly in the younger ages and partly from the oral-cavity, especially in the later life periods, when enamel-free surface areas develop, through which the 210 Pb- /210 Po-/ diffusion, tending to the teeth, rises. In addition to this the pulpal blood flow even in the healthy teeth reduces and the number of the devitalized teeth increases. On the contrary the 210 Pb can reach the bones via blood stream only. Consequently it appears evident that the skeletal 210 Pb'activity, or the cumulative radon daughter exposure of miners can be only approximately estimated from the 210 Pb-content of the teeth* The difference demonstrated between the 210 Pb-contents of teeth of non-smoker coal miners as well -as that of non-smoker control males can even more be higher for the skeleton.

Reference: E.P.RADFORD, VIIMA R.HÜMP and DWYN SHKKRÏ, Analysis of teeth and bones for alpha emitting elements, Radiation Research lg, pp. 298-315. /1963A URANIUM AND Ra-226 LEVELS UT AUTOCHTHONIC PISHES OF AN ADRIATIC ESTUARY Emilija HorSié and Alica Bauman Faculty of Veterinary Medicine 71000 Sarajevo, Yugoslavia Institute for Medical Research and Occupational Health 41000, Zagreb, Yugoslavia

In the estuary of the river Neretva passing through a mud lake, salt and fresh water are mixed. As a result considerable changes in aquatic organisms along a 30-mile-stratch are discovered. Species of sea water fishes such as merlucius vulgaris, scomber scomber, clupea pilikhardia, molluscae such as mytilus galloprovincialis and crustaceae as nephrops norvegicus are found in the estuary. Several miles upstream fresh water fishes typical of the Neretva river and the connecting mud lake are found. There are umbra Krameri, scardinius crypthophtalamus, chondostrome Kheri, leuciscus leuciscus, and cara- ngidae. Levels of radioactivity have not been previously measured in these fishes. Some fishes have been found ex- cellent indicators of fission activity. The natural radioactivity levels in sea water and river water were determined. In sea water the average values were 3,4 ug U/l and 1,6 mBq/1 of Ra-226 (l). The lake and water from the Neretva river contained 0,25 ug U/l and 39 mBq Ra-226/1. Sea water fishes had 0-1.39 ug U/kg of fresh fish, molluscae and crustaceae. Different values were obtained for fresh water fishes. All the above mentioned species had the same level of uranium as sea water fishes except scardinius erythophtalmus which had 12.0 ug U/kg and chondostrome Kneri which had 4(2.0 ug U/kg of fresh fish. Ra-226 levels were in all fresh water fishes higher than in salt water species, with highest results in scardinius erythophtalmus 1.35 Bq and chondostrome Kheri 1.67 Bq. Concentration factors were determined for all fishes. They were for all sea water species in the range of 0.20 - 1.21 for uranium, and 18.44 - 44.0 for Ha-226. The concentration factors for fresh water fishes were the same as for sea fishes except for sc- ardiniua erythophtalmus 31.58 and chondrostome Kneri 11. 08. Por Ea-226 the values ranged from 1.08 to 38.02 for chondostrome Kheri. Dose rates (u &7/h) to sea water and fresh water fishes from natural radionuclides in water are shown in Tables 1. and 2. Table 1. Dose rates (n Gy/h) to sea water organisms from natural radionuelides in the water

merlucius vulgaris 0.30 x 10""*' scomber scombe- 0.6?x lO""*5 clupea pilihchardia 0.14 x 10"*' " " (can) ' 0 mytilus galloprovincialis 0.21 x lO""** nephrops norvegicus 0 Table 2. Dose rates Cu. Gy/h) to fresh water organisms from natural radionuelides in the water leuciscus leuciscus 1.48 x lO"-7 scardinius crypthophtalamus 12,19 x 10~- chondostrome Kheri 15.29 x 10"^ carangidjio 0.79 x 10"5 umbre Krameri 0.43 x lO"-3

Radiation doses through fish consumption were estimated for the general population and for local fishermen. All calculated radiation doses were well below the annual limits on intake (All). For the general population the radiation dose for sea water and fresh water fishes was within the limits from 2.84 - 21.45 x 10~/. For the local fishermen the highest doses were for fresh water fishes chondostrome Eneri 5.»328 x 10 mSv/yr and for leuciscus leuciscus 1.21 x 10 7 mSv/yr. Literature 1. Technical Report Series No 1?2., IAEA, Vienna (1976). RADIOCHEMICAL STUDIES OF U, Ra-226 AND Th IN LICHENS, MOSS AND WILD LIFE IN CENTRAL YUGOSLAVIA Milosevic Z., Horsic E., Bauman A.* and Kljajic R. Faculty of Veterinary Medicine, 71000 Sarajevo, Yugoslavia Institute for Medical Research and Occupational Health, 41000 Zagreb, Yugoslavia

Data on Pb-210 and Po-210 in lichens, moss and reindeer from the far north are frequently found. Such data for the moderate temperature climate zone are less frequent. Data on uranium. Ra-226 and thorium in such samples aro completely missing for Yugoslavia. For that reason the aim of this investigation was to obtain data on natural radioactivity levels in mountains and forrests of Central Yugoslavia where lichens and moss are frequent, and game such as deer and bear are still abundant. All the samples were collected in the Sutjeska National Park, a part of the Dinarid mountain chain in Central Bosnia. The area from which the samples were collected is 1200 - 1500 m above sea level. It is characterized by extreme heat in summer and extreme high snow conditions in different seasons during the year. This is a wild and partly unexplored part of Central Yugoslavia with the last primordial forests in Southern Europe. Lichens being duplicate organisms composed of fungi and algea living in a kind of symbiosis, effectually accumulate and retain most of the radioactivity from the soil and thus act together with moss as a reservoir of radioactivity. In this investigation peltigera canina was collected. Both the lichen and moss carpet constitute a constant source of external irradiation for man and animals. The plots from which the lichens and moss were gathered were completely covered with them and were not effec- ted by grazing at the time of collection. The samples were collected during 1976 and 1977. The lichen and moss gathered from one place and one species weighted 250 to 300 g after being air dried. The animals were shot in a game preserve and were delivered whole to the laboratory. . All the samples were ashed and measured with a GeLi detector and an ORTEC 1024 channel analyser. The results are given in the following tables. They represent the median value of 3 samples with differences of ± 20%.

36 - Table 1. Natural radioactivity in lichen and moss

U (ng/kg) Ra-226 (Bq/kg) Th (ug/kg) lichen 1340 16.28 1.88 moss 2700 32.56 1.00 The results are all valid for an undisturbed lichen and moss carpet. Table 2. Natural radioactivity in bear and deer

U (ug/kg) Ra-226 (Bq/kg) Th (ug/kg) bear meat 37.5 0.41 0.40 bones 1326.0 14.80 0.75-2.05 deer meat 40.0 0.41 0.40 bones 1300.0 14.80 0.75-2.05 hooves 684.0 8.36 9.73 antlers 3700.0 44.40 8.00

The animals were several years old and the deer antlers were well grown. Discussion The content of uranium and Ra-226 was much lower in lichen and moss than could be expected compared with data for Pb-210 and Po-210 in Artie food(l).'Thorium content in all samples was very low. Parallel thorium data for comparison were not available, but the present amount of thorium is again a proof of its insolubility in .biological materials. The quantities of U and Ra-226 in the meat of bear and deer were 30 ~ 40 times lower than in the bones. The range of activity in bears (bone and meat) was nearly the same as in deers. The highest results were obtained in antlers. Uranium and Ra-2 26 concentrations were nearly 100 times higher than in meat and exceeded the content of hooves 5 to 6 times. Thorium in deer and bear compared to lichen (peltigera canina) and moss was very low, being 9.73 ug/kg in deer hooves and 8.0 ug/kg in antlers. The results are a specialy interesting because of the location of collected samples 5 an environment unspoi- led by human interference at present very hard to find in Europe at all. Literature 1. P.V. Ramzaev, M.N. Troishaye et al: II ÏRPA Europ, Cong. Radiation Protection, Budapest (1973) 417. THE CHAKACESRISTICS OP BADIATÏOBS IH IBS HUMAN EJVIECKM3ÏT 2&saharu OBUTO, Xoicbl IZDMO, Hidekasu KUMIGAI, Takeo K1TCX7 and Tatsuji BAMUU The Institute of Physical and Chemical Research Wako-shi, Saitana, 351, Japan A portable scintillation spectrometer with a spherical Nal(Tl) seintillator of 3 in* in diameter and of about 10 kg in weight was used to study the characteristics of environmental radiations* The energy spectrum of incident photons was obtained by the peeling-off method from the lower-energy part below 3 MeV of the measured scintillation spectrum. And the cosmic-ray components were defined from the higher-energy part above 3 &V of the same spectrum. Measurements were carried out in various situations of the human environment such as; indoors and outdoors, in vehicles and trains and on airplanes, in open fields and caves, and on sea and lake. And the following conclusions were obtained. 1. The energy distribution of gamma-rays in the human environment has least dependence on locations. 2. The intensities of gamma-rays as well as cosmic rays in the human environment has great dependence on locations. Especially in crowded cities is the variation greater. 3. The intensity and energy of radiations in open fields are not necessarily representative in the human environment around the location. 4. Buildings and their materials make great influences on both gamma-ray dose and cosmic-ray dose. 5. The conversion factor of exposure rate into photon flux density upto 3 MeV, in unit of (pl",ton/ca2'sec)/(uB/nr), is nearly equal to 1*0 in almost all situations of the human environment. This value ia a smaller than that of 1*2 to 1.6 in open fields. 6. The conversion factor of exposure dose into gonad dose, in unit of rad/R, is estimated 0.74 for male and 0.66 for female based on the depth dose data in ICRP Publication 21. The portable scintillation spectrometer with a spherical scintillator is found to be very powerful for the measurement of environmental radiations. This spectrometer «as used for the intercomparison study made at SEE III held on April 29» 1978, in Texas, U.S.A., and good results were obtained. RADON-222 IN POTABLE WATER SUPPLIES IN MAINE: THE GEOLOGY, HYDROLOGY PHYSICS AND HEALTH EFFECTS C.T.Hess, S.A.Norton,W.F.Brutsaert.R.E.Casparius,E.G.Coombs,A.L.Hess The University of Maine, Orono Maine, 04469, U.S.A.

For the past year, a team of researchers at the University of Maine at Orono has been studying the content of naturally- occuring radioactive gas 222^ (radon) in the potable water supplies in Maine. The objectives of the studies have been: 1) to obtain up to 2000 samples of groundwater and to measure them using a new inexpensive liquid scintillation technique; 2) to collect 350 samples of water from drilled wells, private water supplies and some public water supplies with the purpose being to determine their physical, chemical and geological characteristics in order to describe the geographic distribution of areas of high radon; 3) to determine the levels of radon gas in the hone environment of 10 sample homes, describe the type of housing and level of radon in their respective water supplies; 4) to prepare a map showing the distribution of sample points with radon levels; 5) co calculate the statistical association of radon T

MULTIPARAMETER ANALYSIS OF TEMPORAL CHANGES OP THE Ra- AND 222Rn- CONCENTRATION IN A MUNICIPAL DRINKING WATER SYSTEM

F. Steinhausler, W. Hofmann and E. Pohl Division of Biophysics, University of Salzburg A-5020 Salzburg / Austria

At present several attempts are being undertaken to find population groups, who are non-professionally exposed to elevated atmospheric levels of radon and their decay-products. These groups could then be studied for a causal relationship between the inhalation of radon daughters at environmental levels and lung cancer induction without the simultaneous presence of other co-carcinogens, such as dust or diesel fumes in the uranium miner studies. Groups potentially suitable for such a study are the consumers of radon-rich water as have been identified in the Helsinki area (Finland) and some counties in Maine (USA), where radon levels in the drinking water can exceed 100 nCi/ liter (1, 2). Due to domestic use the radon is deemanated and, along with its decay products, inhaled by the inhabitants of the dwellings. The basis for the characterization of any population group by radon levels in their community water supply system is the statistically significant determination of the mean Rn content in the water at the single sites. This requires the consideration of the temporal variation of the nuclide concentration in the water and its dependence on environmental parameters. The same is valid with regard to the determination of the bone-seeking radionuclide ^^Ra in water. In a program over several years a network of stations was defined in an European city of medium size (Salzburg/Austria) and the ^2"Ra- and 22%n-concentration was monitored in the public drinking water system (dws). At defined stations water samples were taken repeatedly directly at the well-heads, respectively reservoirs. In addition water was also sampled at various consumer endpoints, whose water was supplied by different origin. The Salzburg dws receives its water mainly from Alpine spring water and ground water. Water samples for radium-, respectively radon-measurement were taken in 2-liter, respectively 0.5-liter glass bottles at the defined sites. The nuclide concentration was determined by deemanation methods in the laboratory, using ionization chambers in connection with FET-electrometers (3). Additional samples were analysed with gamma- respectively alpha-spectrometric methods, using a high-efficiency, shielded Ge(Li)-detector system respectively Si-diode in connection with computerized multichannel analyzers. In this manner about 1800 Ra- and 'Tin-measurements were carried out. Extensive multiparameter statistical analysis of the radionuclide data was performed together with data on the following environmental parameters: a) meteorological variables: precipitation, soil temperature and snow cover b) hydrological variables: ground water level and turbidity. In the paper the nuclide-specific variation of the concentration with time will be discussed. Special emphasis is given to the simultaneous influence of several superimposed parameters and their changing contribution at different annual seasons.

References: (i)0. CASTHEN, Radon in Finnish dwellings - aspects of epidemiological studies and radiation protection, Proc. Radon Specialist Meeting, Rome, March 3-7, 1980. (2) T. F. GBSELL, H. M. PRICHARD and C. T. HESS, Epidemiologie implications of radon in public water supplies, Proc. Radon Specialist Meeting, Rome, March 3-7» 1980. (3) E. POHL and J. POHL-RÜLING, Determination of environmental or occupational Rn 222 in air and water and Ra 226 in water with feasible and rapid methods of sampling and measurement, Health Phys. 31, 3^3, 1976. I I I - A ! 5

Radon Progeny on Biological Surfaces and Their Effects. ^ E.A. Martell and S.E. Poet, National Center for Atmospheric Research , P.O. Box 3000, Boulder, Colorado.

It has long been recognized that most of the lead-210 and polonium-210 associated with vegetation is accumulated on plant surfaces as natural fallout. It has been less widely appreciated that a large fraction of the lead-210 atoms on biological surfaces were deposited as precursors of lead-210, the short-lived radon progeny. Thus, there is a high frequency of alpha, 3 and Y disintegrations on biological surfaces, a frequency dependent on the air concentration and properties of radon progeny and on rates and mechanisms of deposition. An understanding of the mechanisms of accumulation of short-lived radon progeny on biological surfaces, and the frequency of alpha emissions on such surfaces, is basic to an assessment of biological and health effects. It is the purpose of this paper to make a preliminary assessment of these processes and effects. When radon decays by alpha emission in air, the polonium-218 recoil atom acquires a positive charge of +2 due to: (1) removal of one or more orbital electrons during alpha particle emission, and (2) further ionization by collision of the energetic recoil atom with air molecules. A large fraction of the recoil atoms become attached to small airborne condensation nuclei (hygroscopic particles <0.1um radius). Both the unattached and attached fractions of radon progeny diffuse to and accumulate on biological surfaces. A proposed mechanism for the selective deposition of positively charged condensation nuclei on negatively charged biological surfaces is described. The frequency of alpha emissions on biological surfaces can be determined experimentally. The accumulation of lead-210 atoms on biological surfaces can be determined with a high degree of sensitivity by alpha spectroscopy of polonium-210 after ingrowth. The fraction of lead-210 which is deposited as precursors can be estimated from the known, or measured steady-state concentrations and aerosol properties of lead-210 and its precursors in air. Blanchard (1969) showed that in uranium mine atmospheres there are 12 to 36 percent as nany airborne precursor atoms as lead-210 atoms. Our experimental results indicate about 2 to 5 percent as many precursor atoms as lead-210 atoms in continental surface air. For indoor radon progeny under relatively dust free conditions, the airborne precursor fraction will exceed 50 percent. In addition, due to differences in aerosol properties, deposition velocities are appreciably higher for precursor atoms than for airborne lead-210 atoms. There are 3.7 x 107 atoms per picocurie of lead-210 and one prior polonium-214 disintegration

* The National Centex for Atmospheric Research is sponsored by the National Science Foundation.

- 42 on surfaces for each lead-210 atom deposited as a precursor. Thus, for residence times in the range of a few days to a few weeks for natural fallout on biological surfaces the polonium-214 activity is thousands of times greater than that for polonium-210. Based on the above considerations and on the measured accumulation of lead-210 on tobacco erichomes (Martell, 1974) it is estimated that there are between 103 and 10" polonium-214 disintegrations per cm2 of tobacco leaf surface per month. Similarly it is estimated that there are between 10s and 106 polonium-214 disintegrations per cm2 per year on exposed skin surfaces from 0.01 WL of indoor radon progeny, the average level of public exposure. Thus basal cells of the epidermis at depths within the alpha track range, experience a high frequency of alpha interactions over the long period of skin cancer induction. The biological and health implications of this high frequency of alpha emissions on biological surfaces is discussed. Basal cells and germ cells receive a radiation dose of about 100 rem per alpha interaction — about 1,000 times the annual background radiation dose. It is proposed that alpha interactions with cell nuclei may explain the incidence of chromosome aberrations which occur spontaneously in small organisms and in cells in vitro. It also is evident that bronchial cancer and skin cancer are induced by multiple alpha interactions with basal cell populations. Improved knowledge of the frequency of alpha emissions on biological surfaces will help to clarify the role of alpha emitters as mutagens and will provide improved basis for modeling multiple alpha interaction mechanisms of cancer induction.

REFERENCES

Martell, E.A., 1974. Radioactivity of tobacco trichomes and insoluble cigarette smoke particles, Nature 249, 215-217. Blanchard, R.L., 1969. Radon-222 daughter concentrations in uranium mine atmospheres, Nature 223, 287-289.

- 43 Ill-fl 16

The Ra-226, Pb-210 and Po-210 Contamination of the Black Forest

H. Schutte!kopf, H. Kiefer Kernforschungszentrum Karlsruhe Hauptabteilung Sicherheit

Black Forest is the most important natural high background area in the Federal Republic of Germany. The high natural uranium contamination in the Black Forest causes an accordingly high Ra-226, Pb-210 and Po-210 contamination. This contamination was used to evaluate the extent of contamination in the environment, the mechanisms of radionuclid transport to man, and the radiation burden of the population due to natural Ra-226. Ra-226, Pb-210 and Po-210 were measured in air, soil, sediment and rock samples. Spring, surface and drinking water was examined for its radionuclid content. The contamination of fish, milk and practically all foodstuffs produced in the Black Forest were measured. Moreover, grass and hay samples as well as many wild plants have been analyzed for Ra-226, Pb-210 and Po-210. About 1000 samples have been analyzed for the mentioned radionuclides using very sensitive measurement techniques for natural radioactivity. Since water and fish samples, grass and milk samples, soil and grass samples, etc. were collected jointly in every case, it was possible to calculate many transfer factors. The following transfer factors have been determined: fish/water, grass/soil, milk/grass, water/ sediments, foodstuffs/soil. The latter include the transfer factors for wheat, barley, oat, eggs, beef and deer, potatoes, vegetable, etc. The natural radiation burden was calculated on the basis of the consumption habit by the average member of the population. The environmental contamination by effluents of two uranium exploration mines, one situated in the Northern and one in the Southern Black Forest, is negligible low. Measurement in the body counter of the Ra-226 body burden of 28 persons living in the area under consideration concluded tne research program. An investigation of the Ra-226 content in the teeth of the population living in this area for the determination of the differential Ra-226 body burden is presently performed. The radioecological and health physics aspects of the results are discussed.

- 44 - ALPHA SPECTROSCOPIC TECHNIQUES FOR FIELD MEASUREMENT OF RADON DAUGHTERS

W.W. Nazaroff, A,V. Nero, and K. Revzan

Energy Efficient Buildings Program Energy and Environment Division Lawrence Berkeley Laboratory Berkeley, GA 94720 March 31, 1980

Measuring low concentrations of radon daughters in buildings and in outdoor air requires techniques that are more sensitive than those Gen- erally applied in mines, At present, most field measurements of radon- daughter concentrations employ cotal alpha techniques, although spectro- scopie methods can be far more sensitive. The latter mechods, which dis- criminate between alpha particles from polonium-218 and p^lcnium-21i. i.a-.'t1 been largely restricted to the laboratory because the bulkv and expensive instrumentation they require mjtkp.b field applications impractical. Xov. however, advances in integfat?^ circuit technology have led to the development of lightweight field instruments based en alpha spertroscopy. In this paper, we discuss the selection and optimization of neasiiramenc tec)- niques for such instruments. In selecting a technique fcr 'measuring radon daughters, one wants - ideally - to achieve both measurement detail, of ten-meaning high precision, and short measurement timej objectives which may conflict in practice. However,, in any given research setting, one or the other objective may be emphasized according to exneriniental goals. In field surveys, sone detail can be given up in favor of a rapid procedure. On the other hand, in studies of the behavior of radon daughters under various environmental conditions, precise individual daughter measurement is called for rather than a short measurement time. A relatively low-cost instrument that can be used for either application has been built at the Lawrence Berkeley Laboratory; it is shown sche- matically in the Figure. Air is drawn through E filter (0.8 micron pore, mixed cellulose acetate and nitrate) at 10 to 20 liters per minute (lpra"! for a sampling period ranging from 5 to 10 minutes. One minute is allowed between the end of sampling and the beginning of counting during which the filter is transferred to the vacuum chamber. We ensure good energy resolution by evacuating the chamber with a small hand pump before counting. The single-channel analyzer, designed by Keefe1, separates the pulses resulting from polonium-218 and polonium-214 alpha decays. These pulses are recorded in two counters, and the totals can be displayed on the front pa- nel. The prototype is operated manually; however, the addition of automatic timing is in progress. When short measurement time is the objective, as in field surveys, it is possible to use a single counting interval immediately after sampling. The polonium-218 concentration can be measured directly from the total count in the lower-level alpha counter. The potential alpha energy concentration ("working level") can be estimated from a linear combination of the totals in the two counters, as suggested by Schiager2. The ratio of the coefficients can be chosen so that the uncertain equilibrium will affect the estimate as little as possible. Since polonium-218 has a short half-life, its concentration over time tracks well that of radon-222. Thus, with one measurement, we can obtain an estimate of both radon concentration and potential alpha energy concentration. We can use total measurement times from 10 to 20 minutes, and still achieve results that are precise enough to satisfy the goals of field surveys. To measure individual daughter concentrations two counting intervals are necessary. Based on the four count totals, we can calculate the three daughter concentrations as well as the fraction of polonium-214 counts that appear in the polonium-218 counter as a result of the energy lost as the alpha leaves the filter. The timing for this technique has been optimized, with constrained sampling and total measurement times, by minimizing the statistical uncertainity in a linear combination of the radon daughters over a range of equilibrium conditions. Although longer total measurem» it times improve the precision of this method, the gain beyond 50 minutes is small. For a 50-minute measurement, counting from 11 to 20 and 31 to 50 minutes after the beginning of a 10-minute sample optimizes sensitivity. Assuming that the product of the detector efficiency and the sampling flow rate is 1.0 (lpm-counts/disintegration), the uncertainty in individual daughter measurements is roughly 20% at 1.0 picocuries per liter.

References:

1. D.J. Keefe, W.P. McDowell, and P.G. Groer, The Environmental Working Level Monitor, Argonne National Laboratory Report, No. P762SC, prepared for r-.he Office of Radiation Programs, U.S. EPA (September 1978).

2. K.J. Schiager, Radon Progeny Inhalation Study, Colorado State University Report, C00 1500-17 (Fort Collins, February 1970).

46 - RESIDENTIAL RADON OAUGHTER MONITOR

+300V vacuum Ctambtr Solid Stott Surfoet Borritr Otttetor

Filttr Somplt

High Voltagt Supply Counter Upper Ltvtl q Display JL > U^ A- Lower Level«. Preamp Amplifier JL Singlt Channel Counter Anolyztr/Pulst Shoper

XBL 799-7119

Schematic of a portable radon-daughter monitor based on alpha spectroscopy. 11 I-B 2

BLECTHET SYSTEM - A IB» APPROACH II MKASUBIflG BUK*, THOBOH ABS THE DSCAT EBGDGCTS IV BfBLUIGS P. Kotrappa, S.K. Bua, P.G» Gupta, T.3. Mayya, K.S.V. Nambi, A.II. Bhagwat and S.D. Sonan Health Ihysics Division Bhabha Atoaie Besearch Centre Bombay 400 085, HTOIA Had on and thoron, naturally occuring radioactive gases, decay to particulate radioactive decay products carrying positive electrostatic charges (1, 2). This property is used in the electret system developed in our laboratory. Electret is a permanently charged dielectric usually mede from teflon. Such electrets produce electrostatic fields equivalent to that produced by 2000 to 3000 7 battery. The system consists of 10 litre SS mesh chamber lined with 25 nm thick polyurethene foam from outside. A 6 cm diameter electret with a negative charge is fixed at the top centre of the chamber. 'Alien 3uch a chamber is left in the atmosphere, polyurethene foam lets in only the radon and thoron gases into the chamber and not the decay products present in the atmosphere. The decay products formed Inside the chamber, being positively charged, get collected on to the electret surface* Typical chamber with an electret équivalent to -2000 volts DC, collects 70$ of all the decay products produced inside the chamber, rest goes to walls. After letting the chamber stay in the atmosphere for about 3 hours, the electret is removed and subjected to a programmed counting of alpha radioactivity. Theoretically, this system is analogous to the double filter system and the procedure already available (3) can be used to analyse the data to calculate the concentration of radon and thoron. In analogy with double filter systeri (3), this method with a sampling time of three hourB, has the minimum detectable limit of 30 pCi/nt3 for radon and 100 pCi/m3 for thoron. The electrets are reusable since the collection takes place on a thin mylar foil used for lining the surface of the electret. It should be noted that this is a passive system and it takes aearly 40 minutes for equalising the concentration of the gases inside and outside. This system does not need a pump as in the case of double filter (3) nor does it need an additional electrostatic source as in the case of Cowper'a instrument (4). The system is small, portable and inexpensive. A set of 20 measurements were carried out simultaneously in an uaventilated room with a standardised double filter system (3) and the electret system. There was a good agreement* The electret system's sensitivity can be improved by a large factor using in situ recording of the alpha disintegrations using a solid state nuclear track detector (SSHTL) or TIJ) material the electret. Results of the measurement carried out bj this technique are discussed.

- 48 Electret surfaces being highly charged collect not only the oppositely charged decay products but also the small size neutral aerosols by image charge effect. Tbe# *»eay products of redon and thoron present in the atmosphere are us*jally attached to the small sized aerosols ( \' 0,04 unj present in the atmosphere (5). Such decay productc nay or;may not carry the electrostatic charge» The preliminary investigations indicated that electret collects the decay products free tiie atmosphere at a rate equivalent to the collection by a filtejf- paper at a floir rate of about 0.250 litres per minuts. using this correlation and the subsequent analysis of the alpha activity on the electret or on the SSNTD, it is possible to compute the working levels due to the decay products of radon and thoron. The aim of the present work is to develop and standardise a simple method suitable for determining the concentration of radon, thoron and the decay products in dwellings, with a final aim of the estimation of the inhalation dose to the lungs of people living in high background dwellings. The present system is Ideally suited for the conditions in our country. REFEREHCES j. 1. S.K. Sua, P. Kotrappa and D.P. Bhanti - "Electrostatic charge on decay products of thoron", Am. Ind. Hyg. Ass. J., 39*339 (1978), 2. S.K. Sua and P. Kotrappa - "Comment on the charge on decay products of thoron and radon", submitted to Asu Ind. Hjg. Ass. J. (1530). . 3. P. Kotrappa, S.D. Soman and T.S. Mayya - "modified double filter system for measuring radon/thoron in the environment and In inhaled breath", Proc. of IAEA. Symposium en Advances in Eadiatior. Protection Monitoring, IASA-SM-229/31 t 423 (1979). A, C. Cowper and M.E. Davenport - "An instrument for the measurement of long term average radon levels", Proc. of IAEA Symposium on Advances la Badiation Protection Monitoring, IAEA-SM-229/31 : 413 (1979). 5. P. Kotrappa, D.P. Bhanti* S.K. Sua and P.P. Josh! - "A single stage centripeter for rapid analysis of long lived alpha emitters in air", Health Physics, 27 t 103 (1974). 11 I. -B 3

AUTOMATIC MONITORING OF RADON DAUGHTER CONCENTRATION IN SOIL AIR BY ELECTRODE COLLECTOR

Fujio Tanaka and Yasuyuki Makl

Industrial Research Institute of Kanagawa Prefecture Showa-cho, Kanazawa-ku, Yokohama, Japan

The continuous measurement of radon daughter concentration in ground-water and soil air has been performed by several methods such as ZnS scintillator(1), ionization chamber(2) and aerosol filtration-GM tube(3) counting. This paper presents a simplified and inexpensive apparatus to make automatic and continuous measurement of radon daughter concentration in soil air by using GM tube, while acquiring higher measuring sensitivity. For this purpose the apparatus is paid special consideration on the following points. One is the mechanism to collect as many radon daughter as possible to improve sensitivity even ir. measuring environment of low concentration. The other is the system of configuration to prevent GM tube from radioactive contamination and lower background during the time of GM tube measurement.

The constructed measuring apparatus is shown in Fig. 1. Two methods of positive collecting of radon daughters are introduced in this apparatus. One is the installation of the heater which produces the flow of air around

Sequential Controller ounting Position Timer GM Tube"j-jpre-Am Sealer -Printer Main-Amp H.V.Supply 1 , Space of Tank DC V.Supply

Electrode (§) Charging Gearmotor Contact Collecting Endless Cloth <|) Heater osition Velt (ft) Lid Driving Roller Ground-Water Level Roller I Limit Switch

50 the collecting position, and the other is the at'• acnrr.er of the negative charged electrode. By these r.et:tods v-. daughters are collected to measure positively. : from radioactive contamination of Gl'. tube, the 'o _, .L ~ J ^ position and the counting position are separated airtight as much as possible. A cloth velt sy c — is TV troduced to drive electrode between each posit radon daughters are collected by electrode att R.C n6( velt for a given period, the plate is driver, to the c-ant- ing position and the radon concentration level is res sure?, by GM tube.

One of the measured data is shewn in Fis-.. 2. It shows diurnal variation of radon daughter ooncan-r-at icr.s in air over the ground-water level in :-t storage tank. The radon concentration of ground-water is approximately 1.2-5 pCi/1 by the liquid scintillation counting method. The charged voltage of electrode is -500V DC. The electrode is made of a stainless steel plate. The unit cycle for the measuring operation is 30 min (20 min for collecting radon daughters and 10 min for counting).

It is concluded that this apparatus is available to measure the concentration of radon daughters exhaled from ground-water with enough sensitivity. Additionally it can be mentioned that this measuring system is able to be modified to measure radon daughter concentrations even in the lower concentration in environmental levels, by installing two electrodes to obtain enough time to collect and count.

1030. Atmospheric Pressure o o 1020 O o O o 1010 15 Air Temperature u 10 0 5 0 Radon Concentration

•• '

E ?: 4

17 18 19 r- O 20 21 22 Fig2 May,1980 References 1. M. E. Wrenn, H. Spitz, and N. Cohen (1975). Design of a continuous digital-output environmental radon monitor, IEEE Trans. Nucl. Sci. NS-22:645.

2. L. Cathey (1978). Continuous radon concentration monitoring, Rev. Sci. Instrum. 49(12):l670. 3. J. D. Melvin, M. H. Shapiro, and N. A. Copping (1978) An automated radon-thoron monitor for earthquake prediction research, Nucl. Instr. and Meth. 153(1) 239.

52 Passive differentiating track detector for the measure ment of exposure and equilibrium between radon and its progeny in the ambient i* Doaanski T», Chruécielewski W., Swi^tnicki G, Institute of Occupational Medicine, 90-950 Lód£,P.0.Box 199» Teresy 8 Str., POLAND Abstract The Paper presents the results of investigation of the Passive track detector designed to measure exposure to radon decay products (RnDP) as well as to determine equilibrium between radon ( Rn ) and RnDP in the ambient air. Such a detector is called a passive differentiating track detector (PDTD). The idea of design is based on two detection films one of which is sheltered in a cell with the material which allows diffusive permeation of radon but restrains RnDP and their radiation. 3?igure 1 presents a scheme of the design.

COVER and films holder Pig. 1. Scheme of PDTD. OPEN SMCE /E - volume of

GRID DIFFUSE SHIELD - space over the film ixotector radon permeable sheltered portion permeable to radon material and barrier and daughters to daughters of film/

(Alpha energy absorber)

Film exposed Covered poriion lp ambient air of film C^Rn* daughters)

Kodak film LR-115 (II) is used as the detection material.. The PDTD was tested in the air inside a special experimental chamber(Do79') which ensured RnDP : Rn equilibrium within the wide range corresponding to the so-called ( IGRP77 ) equilibrium coefficient F whose value ranges from 0.01 to 0.9. The test was carried out for a few different materials used as barriers for RnDP. The following parameter was x7Porformed under USEPA"Washington D.C. contract No 0.5-536-5. Domaóski QJ. et al* 2nd paga asumed to characterize equilibrium in the ambient air:

where: D.= - are the surfacial trade densities on the un- sheltered and sheltered film, respectively to the index 1 or 2. As a result of tests» if was found that parameter considered as a function V a V( F) is hardly sensitive to F variation, i.e. it is not sufficiently sensitive a function of RnDP ï Rn equilibrium since \7 = a-F , where: a = 4- and b cannot be greater than 0.24. PDTD of similar design has been described by Prank and Benton (Fr77) as well. The results obtained now, howeveiy lead to completely different conclusions, which are the following: - theoretically, variation of parameter V used to determine RnDP : Rn equilibrium can have the maximum range of(1 - 3)for the extremal equilibrium states. Practi- cally the range is even narrower (1 - 1.3) within F variability between 0.08 and 0.8, - PDTD design based on two detection fields» one of which is sheltered by the so-called diffusion barrier against RnDP does not ensure close relationship between parameter V and RnDP : Rn equilibrium, - PDTD of the type mentioned above as used to determine RnDP : Rn equilibrium in the environment, and especial-* ly when applied in the personal dosimeter is not a guarantee of the proper assessment of F mean value which exists during the exposure time* References Do79 Domanski T., Chruscielewski W., Orzechowski W., 1979, "Experimental Chamber Simulating the Equi- librium between Rn and Its Daughters in Mine Air", Health Physios /submitted for publication ICRP77 International commission of Radiological Pro- tection Radiation, 1977( "Protection in Uranium and Other Mines, ICR? Publication 24, Pergamon Press, Oxford Fr77 Frank A.I.» Benton B.7., 19771 "Radon Doaimetry Using Plastic Nuclear Track Detector11, Nucl. Track Detection. 1, 149 11 I-8 5

A PASSIVE INTEGRATING RADON MONITOR FOR

ENVIRONMENTAL MONITORING

H. W. ALTER Terradex Corporation 460 N. Wiget Lane Walnut Creek, CA. 94598

R. L. FLEISCHER General Electric Research and Development Center Schenectady, NY 12301

ANDREAS C. GEORGE Environmental Measurements Laboratory, DOE 376 Hudson St. New York, NY 10014

•Improved Track Etch alpha particle detectors have been calibrated against standard radon atmospheres. Detectors were exposed in several configurations to permit the measurement of radon-only unaffected by radon daughter concentrations. A statistical analysis of sensitivity shows that reliable exposure readings can be made down to 0.2 (pcx/t) - months. 0 Track Etch detectors are completely passive and integrating and may be of use in a, variety of radon monitoring areas. ' I 't -3 <:

A PILOT STUDY OF INDOOR RADON LEVEL USING A SHORT TIME FILTER TECHNIQUE AND A TIME INTEGRATING PASSIVE RADON MONITOR.

M. Urban, H. Kiefer, E. Piesen Kernforschungszentrum Karlsruhe Hauptabteilung Sicherheit

The inhalation of short-lived radon daughters in dwellings is one of the most important radiation risks for the population. Due to human activities today, the effect of reduced ventilation increases the indoor radon concentration and thus the population dose significantly. On behalf of the Federal Ministry of Interior a pilot study on the basis of two different techniques has been performed to establish a suitable detector system which may be used for a country-wide investigation of the current population dose in the Federal Republic of Germany. The active technique applies the short-term collection of radon decay products by using a glass fibre filter of 20 cm diam.,a gas flow of 1 m3/min and a sampling time of 3 min. After sampling the time- dependend decay of the a-activity on the filter was measured by means of a sealed large area argon-methan proportional counter in front of the filter. The concentration of the different decay products can be analysed on the basis of the count-rate distribution and the "Weighted Least Squares"technique. This method provides the analysis of short-term concentrations of radon/thoron daughters with a lowest detection sensitivity of 0.05 pCi/1 for radon daughters and 0.001 pCi/1 for thoron daughters. The other technique is a time-integrating one and makes use of a passive radon monitor. Inside a diffusion chamber a-particles from radon and daughters are registrated by a Makrofol E track etch detector (electrochemical etching technique). The radon monitor provides the long-term accumulated exposure in terms of'Working Level Hours" (WLh) up to periods of one year with a sensitivity of 0.3 pCi/1 after 3 month accumulation. The radon concentration has been investigated in dwellings located in different geological areas. The 200 experimental results of the pilot study will be discussed taking the short-term results as a first approximation because of the relatively high change of the exhalation and ventilation rate in the room and the 90 days accumulation as a more reliable time independent value for the estimation of the lung dose. The following assumptions are used to calculate the population dose: the UNSCEAR 1977 dose conversion factors of 0.2 rad/WLM for radon daughters and 0.1 rad/WLM for thoron daughters; an equilibrium factor of 0.4; a 7000 hours stay in houses during one year. The frequency distribution found for the concentration of radon/thoron daughters may be described by a log-normal distribution with a most frequent value of 1.7-10" WL / 1.5*10" WL, and a variation from 0.38*10 WL to 50-10 WL (Rn daughters) and from 0.21-10"3 WL to 19*10" WL (Tn daughters). The short-term measurements result in mean inhalation dose of 400 mrem/a with extreme values of 190 mretn/a and 8200 mrem/a compared to the long-term accumulated results of 460 mrem/a and a variation from 110 mrem/a up to 25.000 mrem/a. The results are discussed in more detail taking into account additional data about building material,type of Houses and the geological situation in the investigated areas. Application of a Y- Y-coincidence method for measuring the age dependancy of Ra-226 in human bone and also the concentration of Radon in indoor and outdoor air

B. Glöbel, H. Huth

Institut fur Biophysik UniversltSt des Saarlandes D-665o Homburg (Saar) West-Germany

Ra-226 in equilibrium with his shortlived daughters can be detected by the registration of the Y-radiation from Bi-214. In the decay-scheme of Bi-214 exist coincidences of some Y-energies above 0,8 MeV with that of o,6o9 MeV. Our measuring device uses two large NaJ(Tl)-Detectors (8" x 4") which are connected by a fast coincidence circuit. The detector arrangement was positionned in a human body counter with a steel-shielding of 8".

.1 •

9 20 30 tO Altwtol

Fig. 11 Concentration of Ra-226 in human bone depending on age In nearly 1ooo human bone samples, with known Sr-9o-content, the age dependent concentration of naturally accuring Ra-226 was measured. The investigations were carried out in agegroups from zero to fourty years (Fig* 1). The natural Ra-226-concentration and the content of Sr-9o from nuclear testexplosions will be compared and discussed. In the second application. Systematically the condition of adsorption for Radon on charcoal was investigated. The adsorption is dependant from temperature, moisture and velocity of the air stream over the charcoal. The distribution coefficient between air and charcoal (concentration in charcoal to concentration in air) was determinated at 2o° C to be 2100. The measurement of Radon we carried out by analysing the 7 -v-coincidences between the energies from 0,8 to 2,8 MeV with that of o,6o9 MeV. The detection limit for Radon lies in the region of o,oo1 pCi/1 air. The results of indoor and outdoor investigations are reported and discussed. I7Ï-B S poo Rapid Measurements of Rn in Water by In-Situ Ge(Li) Spectrometry KAZUHISA KOMURA and MASANOBU SAKANOUE Low Level Radioactivity Laboratory, Kanazawa University, Wake, Tatsunokuchi, IsMkawa 923-12, Japan 222 "A new method was developed to determine Rn concentrations in water by in-situ y-spectrometry with a portable Ge(Li) detector. The detector was specially designed for in-situ measurements of environmental radioactivity and has a 30 cm of long-necked detector head, which makes it possible to immerse the detector directly into water sample collected in a bucket. The detection efficiency and energy resolution are 16 % relative to 7.6cm x 7.6 cm Nal(Tl) and 2.0 keV FWHM at 1.33 MeV. Usually 80 1. of water was collected in a 90x100 cm thin polyethylene bag put inside of a commercially available 90 1. plastic bucket. For 222Rn measurement,special care was paia to avoid the loss of radon during the sample collection and storage. Since Z22Rn does not emit y-ray, measurement was started after the lapse of at least 3 hours to allow the radioactive equilibrium*between 222R0 ancj Y-ray emitting daughter nuclides 214pb and 214Bi. Measuring time was usually one to several hours depending on 222R0 concentration and required accuracy. For the utility of this method, no shielding was applied for external y-rays from soil, air and other sorroundings. However, large volume of sample water serves as a good shielding particularly for low energy y-rays. The minimum detectable 222R0 concentration is about 30 pCi/1. for 1 hour of in-situ measurement of 80 1. sample under the typical background radiation of 5uRad/h. The detection efficiency was obtained by a simple Monte Carlo calculation, which includes the Y-ray attenuation by water, geometrical efficiency and the experimental efficiencies measured by standard point sources. 2?? 222 Table 1. shows the example of Rn Table 1. Rn concentration in water measurements for underground water near-our laboratory. As known from Sampling point "*Rn concentration Table 1 , ^ Rn concentrations are (depth of well) (pCi/1) high enough than the detection limit Kamikaihotsu (600m) 560 ± 50 of this method. Mitsukuchi (40m) 880 ± 30 This technique can be applied for Wake (1 .2m) 490 ± 20 other radionuclides in water, milk, Deguchi (80m) 650 + 20 and various types of liquid radio- Melted snow 20 ± 20 active waste. In Table 2 the detection limits for some radionuclides of interest from the view point of Table 2. Detection limits of some environmental radioactivity are given radionuclides for one hour of in-situ measurement. Nuclide Measured Detection limit The detection limit is defined as Y-ray (oCi/1 .) D.L.=2/(BKG)x(2FWHM) 1-131 364keV 12 As known from Table 2, detection Ru-103 497 12 limits are around 10 pCi/1., which is Cs-134 605 9 as low as 1/10 of maximum permissible Cs-137 662 12 level of liquid waste. Mn-54 835 8 This method is sufficiently Co-60 1332 10 sensitive for the monitoring of liquid waste from nuclear facilities. Conditions: sample volume- 80 1. measuring time- 60 min. *Growing-up of ^^Pb and ^^.j was dynamically checked by y-spectra.

- 60 rn —s 9

The Analysis of Dissolved Alpha Activity in the Radiation Environment

C.J. Bland Physics Dept., University of Calgary, Calgary, Alberta, Canada T2N 1N4.

Abstract

At the previous meeting in Houston, the author (Bland 19 78) gave details of methods for collecting activities of dissolved radionuclides (e.g. Ra 226, Th 230) using filters of manganese impregnated fibres. This method was based on techniques developed by Moore and Reid (1973). Further studies have revealed that the extraordinary ability of hydrated manganese dioxide to adsorb certain radioactive cations was discovered by pioneer workers in radioactivity and indeed methods were devised to extract radium from water using this substance as far back as 1913 (Ebler and Bender 1913). A striking natural example of this phenomenon! is exhibited 'by the mineral "reissacherit" which occurs in the Bad Geistein area of Austria as a sediment in mineral springs. In certain locations, spring water containing less than lpCi/1 is associated with these sediments containing activities of several 1000 pCi/g as Ra 226 (the author is indebted to Professor Pohl and Dr. Pohi-Ruhlir.g for information and samples).

Experiments have been carried out to develop a simple cartric.C:? filter that can be impregnated with manganese and which is capable of removing radium and certain ocher nuclides ac flow rates j.bove 51/min. By the use of a portable pump, researchers in the field may preconcentrate the activity from several hundred litres of water. After receipt in the laboratory, the activity may be removed from the filter by recirculating dilute nitric acid.

In areas where the dissolved activity is quite high (e.g. effluent from Uranium mines) the author has developed a special plastic disc containing manganese. After immersion in water for several hours, the surface activity is sufficiently high and the thickness of the adsorbing layer thin enough for high resolucion alpha spectrometry to be carried out without any chemical prepara- tion. (Bland 1979).

Developrojnts in the field of alpha particle spectrometry will be discussed. The author has computed the effective geometrical factor for alpha particle sources, including self-absorbtion, as a function

f- '• of source thickness and counter to source distance. These calculations may be of be of value whenever it becomes difficult to prepare a standardized source for comparison with one of unknown activity. A method for performing alpha particle spectrometry simultaneously on several separate sources (in our case six) using an inexpensive PET™ desk computer will be described.

Actual case histories of the analysis of spring waters in the Uraniferrous regions of Northern Saskatchewan will be described if time perimits.

References Bland, C.J. Proc. Natural Radn. Envir. Ill Conf., Houston 1978 (in press). Bland, C.J. Int. J. App. Radn. and Isotopes J3<), 557-561, 1979. Ebler E. and Bender W., Z. Anorg. Chem. 8±, 77, 1913. Moore, W.S. and Reid, D.F., J. Geophys. Res. _7Ji, 8880, 1973.

62 - .11-3

NATURAL CONTAMINATION IN RADIONUCLIOE DETECTION SYSTEMS N.A. Wogman and J.C. Laul Physical Sciences Department Battelle-Northwest Richland, Washington (U.S.A.)

There are two sources which contribute radioactivity to natural and synthetic materials. These sources are natural radioactivity from the earth's crust and radioactivity produced by man. Thus, the potential exists for radioactive contamination of materials used for radionuclide detection systems. In designing low-level gamma-ray counting systems, attempts are made to use the purest of materials as well as sophisticated electronic anti-coincidence shields to eliminate the inherent radioactive background created within the system or from radioactive sources external to the system. This paper discusses the radionuclide contamination that exists in natural materials which are used to construct Nal(Tl), and Ge low-background gamma-ray spectrometers. In order to detect low levels of radioactivity in construction materials, the most sensitive technology available must be used to identify the radionuclide species in a sample. In this study, a multi-dimensional gamma-ray spectrometer system1 (MDGRS) which employs two 23cm-dia x 20cm thick Nal(Tl) crystals as principal detectors was used. The detector system is coupled to a computer memory and uses the gamma-ray decay characteristics of each of the radionuclides for its identification and measurement. Through use of the MDGRS the natural radioactivity in Nal(Tl) and Ge(Li) spectrometer construction materials have been measured and are shown in Table I. In general, Al contains high quantities of 232Th and 238U with minimal quantities of ^°K. Stainless steels contain 60Co although in general they are becoming cleaner as the 60Co use in iron fab- rication is being eliminated. The radioactive content of foams, cements and light reflective material are quite variable. The magnesium oxide reflective material used in Nal(Tl) spectrometer construction contains 232Th, 238U, and 40K; calcium carbonate does not. Molecular sieve material used in Ge spectrometers contains 4-9 dpm/g of sieve. As is illustrated in Table I, many construction materials used for gairma-ray spectrometer systems contaminate these same systems. Only through a judicious choice of materials can systems with the lowest achievable background be assembled. It should be noted, however, that the lowest achievable background of a spectrometer allows the further study of radioactivity in construction materials used in future generations of gamma-ray detection systems. The degree of contamination can be minimized in some ways. Quartz light pipes can be placed between the Nal(Tl) gamma-ray detectors and glass phototubes. Ceramic phototubes may eliminate some ^K background. Systems can be constructed of titanium metal using pure calcium carbonate reflective coatings. In diode spectrometers, molecular sieve material car? he placed at 90° to the detector allowing shielding to >•>

TABLE I. NATURAL RADrOACTJVrTT IN Nal(Tl) AND Ge(LO G*MMA- RAV SPECTROMETER CONSTRUCTION MATERIALS {dpm p«r g» of s ample)

Spectroneter Assembly Mauri a 1 "»Th Al 25} 0.12 ' «0.07 1.0 Al 6061 0.42 0.04 «0.05 Al 1100 0.24 «0.017 «0.06 Al 1100 0.08 «0.026 «o.n Al (3003 0.10 «a. 026 0.56 Al (sheet) <0.08 «0.1 «0.4 Al (sheet)

6 5 11 I-B '12

INDOOR AND OUTDOOR GAMMA-RAY STUDIES IF AN URBAN ENVIRONMENT IN POLAND

J. Koperski, T. Niewiadomski, S. Ryba Institute of Nuclear Physics, Kraków, Poland

ABSTRACT As a result of previous work (N179) it was found that areas of enhanced gamma dose rates in the natural environment in Poland prevail in the territory running meridio- nally through southern part of the country. A series of surveys of indoor and outdoor gamma-ray fields in an urban environment of five provinces (Fig. 1) was started in 1979 and will be completed in the second half of 1980. Provinces 1, 2, 3 and 4 are those with the highest values of natural radiation outdoors. Province 5, which also lies within the range of elevated natural radioactivity, is particularly interesting due to its highest rate of population and biggest urban agglomeration in Po- land. Total area of the provinces studied is 29433 knr, i.e. about 9.5# of Poland s territory. About 6.2 mln people, i.e. 187& of Polish population, live here. The following kinds of measurements of gamma radiation are being performed: - outdoor momentary measurements over different kinds of beddings in about 350 localities; - indoor integrating measurements in about 1050 dwelling- houses made of various building materials in 143 localities. For outdoor measurements a high pressure argon filled ionization chamber is used. For indoor measurements TL dosimeters together with the Automated Tï System described elsewhere (Da74) is used. The errors of TL and chamber measurements were estimated as up to ±6$ and ii2?ó respectively at the two sigma confidence level. All data obtained are presented as air absorbed dose rates for both indoor and outdoor measurements. The contribution from cosmic radiation is subtracted mathematically. Till now the measurement programme in 382 dwelling- houses of 57 localities and in 233 points outdoors of 151 localities, all within provinces 1 and 2, has been completed. The results obtained show that the outdoor dose rates in an urban environment varies with the kinds of beddings

- 66 - from 2.0 to 19.1 prad h (5.6 to 53.1 pGy a"1) and, on the average, in province 1 equal .7.2 ;irad h"1 .J20.0 pGy s" 9 over grassy grounds, 8.1 urad h (22.5 pG-y s~') over concrete, 8.8 ;irad hr' (24.5 pGy a"1) over asphalt, and 14.5 ^irad h~' (40.3 pGy s"~') over granite coverings. The relative data for province 2 are somewhat lower and equal 6.8 urad ti~] (18.9 pGy s~' ), 8.1 urad h"1 (22.5 pGy s"1),^ 8.6 urad h"1 (23.9 pGy s~1) and 13.5 ;urad h"1 (37.5pGy s~1) over grass, concrete, asphalt and granite coverings, respectively.

ufad h-1 (23.6 pGy s"^) in province 2*. About 73£ buildings monitored were made of red bricks, 25.5^ of gravel-sand prefabricated elements and 1.5^ of wood or coal slags. Dose rates inside the red brick houses are on the average 40$ higher than those inside the houses made of prefabricated gravel-sand elements. This difference is much higher than the difference found for other provinces of southern Poland previously monitored (Ki78, Ko80), which usually i3 "\QFfo. The complete data from all the provinces will be reported in the final paper and will be of great importance for future evaluation of the population doses in an urban environment in Poland.

References Da74 Daszkiewicz O.K., Niewiadomski T., 1974, Programme of an Environmental Dose Survey in Poland utilizing the Automated TL System, p. 713, in the Proceedings IV International Cc-iference on Luminescence Dosi- metry, Kraków, Polajd.

Ni78 Niewiadomski T., Koperski J.t Ryba E., 1978, Natural Radiation Measurements and Interpretation of Their Results in Terms of Dose to Population, in the Proceedings III Symposium on the Natural Radiation Environment, Houston, Texas, USA /in press/. Ni79 Niewiadomski T., Koperski J., Ryba E., 1979, Na- tural Radiation in Poland and its Disturbance in an Urban Environment, Health Physics /in press/. Ko80 Koperski J., Jasinska M., 1980, Risk to Kraków Population of Gamma Irradiation from Building Ma- terials, IPJ Report in press /in Polish/. ?ig.1. Average air absorbed g&maa dose rate3 from terrestial sources .ie the provinces of Poland /S179/. The present prograanie will be executed tn provinces 1 - 5- MEASUREMENTS OF ULTRALOW RADIOACTIVE ISOTOPB CQSCENTRATIONS IN DIFFERENT- SAMPLES AND THRESHOLD OF A SENSITIVITT Of A GAMMA-SPECTRUM ANALISIS E.L.Kovalchuk, A.A.Pomansky, A.A.Smolnikov, A.H.Iemmoev Institute for Nuclear Research of the USSR Academy of Sciences 'Ühe low-background deep underground (660 nrw.e.) installation for )/ -spectra8 analysi2 s allow to measure c cpncentrations of about 10~ g 32!Eh, 10"9g 23Su ^4 io~°g 40K per gram of different samples. It obtained firstly due to decrease of the Nal(Tl) self-background counting rate up to limit 0.0095 counts/min gram in the O.I-3.5 MeV range. Secondly due to large volume of the detector well (

5 9 10 1000 QxlQ'7 1.5xlO" 6.4xlo~9 5*10* 1000 1.2X10"6 2.4xlO"9 9.7xlo"9 500 4.6xlO~6 3.2xlO"9 1.3xlO"8

6 9 8 5x10* 500 7.2xlO" 4 4.3xlO" 1.9X10" Il' "

GEOLOGIC REEXAMINATION OF THE THRESHOLD HYPOTHESIS

J.A.S. ADAMS School of Natural Sciences Rice University,Houston Texas, U.S.A.

70 11/ 2

NATURAL HIGHER BACKGROUND AR2AS AT FICHPSLGSBIHG2

Bruno Sansoni Central Department for Chemical Analysis, Kernforsehungsanlage Julioh GmbH D-517 Julich-1, Federal Republic of Germany

The Pichtelgebirge is a granitic mountain district about 500 to 1050 meter above sea level in the north-eastern border of Bavaria. It belongs to the areas with the highest natural radioactive background in Federal Republic of Germany. This is mainly due to grant it ic rocks containing, smaller or larger amounts of uranium and corresponding radioactive daughter radionuclides. A summary is given about the radioactivity monitoring in this region. The investigations include monitoring of the natural dose rate above the ground in open air during a motor car surveillance, and in houses. From typical rock and soil samples low-level gamma and alpha spectra have been measured* Uranium contents have been determined by neutron activation analysis. The dose rate values are presented as frequency distributions for different areas and objects. Surveillance for does rates has been carried out by car through several traverses in these areas as well as for specific areas, such as, the granitic mountain ridge, quarries \r".th and without uranium minerals, peaty soils, roads of different type, various granitic construction materials for houses, roads and wells in different towns and villages. Comparison of dose rates measured in the two main towns of Fiehtelgebirge, Wunsiedel and Marktredwitz, show characteristic differences. Wunsiedel has more granitic construction materials which explain Mgher dose rate peaks in the regions of 1? to about 30 uR/h with small peaks between 35 and 45 uR/h. Msrktredwitz, with a smaller amount of granite construction and pavement materials has a significantly smalIer "granite" peak in the dose rate distribution= In addition, however, this town shows peaks between about 45 up to almost 70 uR/h. This is unusually high and mere than those found ir. a quarry with uranium minerals. These are the highest dose rates measured in the whole Fichtelgebirge. The high values of the main street, the market place and some few other streets can be associated with the slag-stones of the road pavement. Data on gamma and alphar ray spectra of several relevant rocks and soils are presented together with uranium contents. The dose rates from Fichtelgebirge are compared with those from lower background areas in Germany and with high radioactivity areas in Kerala, India.

7 J - Natural radioactivity around a prospected uranium mining site in a subarctic environment.

E. Holm and M. Nilsson Department of Radiation Physics, Lund University, Lund, Sweden

In the nuclear fuel cycle little attention has been drawn to possible radiological consequences at mining of uranium compared to reprocessing of burned out fuel for example. Especially the natural a-particle emitters such as isotopes of polonium, radon uranium and radium might be released to the environment and transported to man. Also for information to the public the eventually found enhanced levels at uranium mining should be compared to those existing before mining commen- cement.

In an arctic and subarctic environment biological production is low, transfer coefficients much higher than elsewhere and food chains unique. .

In October 1979 a sampling expedition was undertaken to a possible future uranium mine in the vicinity of Lake /Village/ Rörvattnet, Sweden (64.0° N, 13.8° E). At present this uranium ore is under prospectation. The area is low populated but is a region used for reindeer breeding and in a popular resort for wintersport and fishing. Samples were taken mainly of bioindicators such as lichens, mosses, surface soil and soil profiles. Watersa::les from rivers, lakes and ponds have recently been collected as well as different tissues from reindeer.

The lichen-, moss- and soilsamples were analyzed for 210 Po, 226Ra,

228 234 235 238 239+240 Ra and U, U, U as well as full out nuclides such as pu and 137Cs. Typical levels of different isotopes are shown in Table 1.

Table 1. Activity concentration levels of different radionuclides in lichens and mosses (Bq/kg dry)

238U 21CPo 226Ra 137Cs 239+240pu Lichen (Cladonia) 1.5 300 22 440 1.5 Moss 74 125 110 300 1.5

There is no correlation between activity concentration and distance from the ore and there is a large spread in the values depending on site of collection. High concentrations of natural radioisctopes are correlated to high concentrations of artificial fall out nuclides. Uranium concentrations in lichens show that there is a significant re- suspension in the area in spite of that the ground is covered by snow about 7 months per year. The lichen/surface soil activity ratio for uranium plutonium and cesium are 0.035, 3.3 and 2.6 respectively.

Results indicate a higher concentration in biota of uranium and radium compared to an other similar area (1). On bases of measurements of the natural actinides in soil and lichen a few per cent of the activity of f?!1 oui "w'','-.*-- !\r

(1) E. Holm and B. Persson (1978). Radiochenncal and radioecoiogical studies of natural and artificial alpha-emitting radionuclides. The Natural Radiation Environment III, Houston,Texas, USA, April 1978 (In press). SIGH HADOf IBVB1S DETECTED U SOME IOB-UBAÏIÜM MOSS II HSU

I.B. lair, C*£. Eapen and C. Bangarajan Air Monitoring Section Bhabha Atoaic Besearcb Centra Boabay-400 06$ ladiM

In India there are a large number of persona engaged In various types of mining activities. Airborne radioactivity due to Badon-Tboron emanations and their daughter products» if present in considerable concentrations will be a major inhalation hazard to the «n• '«jiu»u«t& are oigb... further deta:W«d studies were curries out *t n%m.\^(t,tc points under-ground, using special equipments which satisfies the sine safety regulations of the concerned nines. In the Solar Gold Field9, although the mines are very deep and the path length of the ventilating air is rerj long, the airborne radioactivity «as only an order of magnitude higher compared to the outside atmospheric air* In all, about one hundred air camples were taken frost 14 up-cast shafts. The collected data showed that the inhalation hazard due to airborne radon daughter product activity is not significant in the Solar Gold Field Mines. The low concentration of uranium/radium in the mine rock» its hard and non-porous structure and the absence of slgnivicant ground water movements could be the rescns for the low radon levels» She measurements carried out in three deep coal mines in Jbaria Coal Fields and another mine in Cbanch Victoria Sector, also in Bihar state, are presented in detail. These coal mines also do not show any significant levels of airborne radioactivity. Qoe major factor, apart from the characteristics of these coal seams, which contribute to the low radon Isvels, is the very high ventilation rate that is being maintained in all these mines for keeping the methane, carbon-monoxide and other pollutants below the permissible levels. Four copper mines under Hindustan Copper Ltd. Singbbhum Dt., Bihar state were surveyed» They were Bakha, Mbsaboni, Surda and Jathargora copper mines. The preliminary studies have clearly indicated higher levels ii* these mines. The concentrations observed in the main ventilating exhausts were many orders of magnitude higher than the normal background in the atmospheric air, and about an order of magnitude lower than the maximum permissible levels. However these levels in the main exhausts indicate only an overall average value and there could be many hot spots underground -where the local concentrations may be very high. Hence a number of measurements were carried out at many points underground and the data are presented. Also in some selected locations separate radon and daughter product measurements were carried out. There'were many locations giving radon levels of the order of 100 pci/1. However the corresponding radon daughter product concentrations in these locations showed that the radon was in a state of high disequilibrium with its daughters and the actual concentrations were therefore only a few tenth* of a Working level. The unattached fraction and particle sixe distribution of the radon deoay products at a few selected locations ara also given* A few Modifications that can be easily carried out to reduce the radon activity level* arc suggested» UADIATION EXPOSURE AND RESULTING RISK DUE TO RESIDENCE ZUID EMPLOYMENT IH A RADON SPA J. Pohl-Rüling, F. Steinhausler and E. Pohl Division of Biophysics, University of Salzburg A-5020 Salzburg / Austria

In many countries water, containing naturally high levels of Rn, is used in spas for therapeutical treatment of various diseases. During collection, supply and treatment using the water radon can emanate into the atmosphere indoors and outdoors. In some spas radon-enriched atmospheres are used directly for inhalation treatment. Therefore in a radon spa the inhabitants are exposed to a more or less elevated radiation burden due to inhalation of radon and decay products. As an exaaple it is demonstrated for the renowned Austrian spa Badgastein, which doses and risks for lung cancer induction occur for different groups of the population. Badgastein (about 6500 inhabitants) is situated in a narrow valley of the Central Alps. In the center of the town 19 springs originate and deliver daily 5 million liter of hot water with a mean 222Rn concentration of UO nCi/liter. The water is collected from the well-heads in large reservoirs and supplied to more than 120 spa hotels and treatment centers. Already during transport of the water to the treatment rooms a large proportion of radon is lost into the atmosphere. Addi- tional losses occur during treatment, where deemanated radon enxers all other rooms connected to the bathrooms, e.g. living- and sleeping-rocms in the hotel. In many series of measurements over several years annual mean concentration values of Rn, its short- and long-lived decay products and ^Pb could be determined for numerous living-, working- and sleeping-rooms as well as for outdoors. A former goldnine near Badgastein was added to the spa treatment installations as a natural inhalation facility of about 22000 m3. In this so-called "thermal gallery" which is entered by patients as well as by accompanying medical staff and maintainance workers, the air has a mean radon concentration of 3000 pCi/lit-r («22 WL), In the spa house adjacent to the thermal gallery the atmospheric radon concentration was also found to be elevated. Based on the measurements of atmospheric nuclide concentrations and applying our dosimetric methods (1, 2) organ doses were assessed for different individuals as there are: employees of the treatment centers and inhabitants from various parts of the health resort, including children and youths. For these dose calculations it was important to carry out time-motion studies for the different physical activities* the latter also have a great influence on the respiratory minute volume. The risk calculations were based on data published for uranium miners (3). In the case of children and youths age-dependent lung dosimetry (k) was combined with risk assessments for cancer induction in dependence of age as derived from data on A-bomb victims (5). The table shows an example for the range of annual radon daughter exposure, the resulting bronchial doses and the annual risk factor rt for lung cancer induction; r+ is defined as the total risk factor per unit exposure (WLM) and 10<. cases.These values in the table are valid for adults only.

References: (1) E. POHL and J. PURL-RULING, Dose calculations due to the inhalation of Rn 222, Rn 220 and their daughters, Health Fhys. 32, 552, 1977. (2) W. ÏÏ0FMAM, F. STEIHHfiUSLER, and E. POHL, Dose calculations for the respiratory tract from inhaled natural radioactive nuclides as a function of age - part I: compartmental deposition, retention and resulting dose, Health Pbys; 37, 517 - 532, 1979. (3) United Hat.ons Scientific Committee on the Effects of Atomic Radia- tion , Sources and Effects of Ionizing Radiation, IAEA, Vienna» 1977. (k) W. KOFMAM, F. STEIHHfiUSLER, and E. POHL, Age-, sex- and weight- dependent dose distribution patterns for human organs and tissues due to inhalation of natural radioactive nuclides, Proc. Natur. Radiation Environment III Symp., Houston, 1978. (5) National Academy of Sciences, Report of the Advisory Committee, The effects on populations of exposure to low-levels of ionizing radiation, National Research Council, Washington, 1972.

Calculated range of annual radon daughter exposure and the resulting zneai dose to the basal cells of the segmental and subsegmental bronchioles for typical groups of the population in the radon spa Badgastein

Population population Exposure Dose to rt (per year groups size (appr.) (WLM/yr) Bronchioles ' (rem/yr) Inhabitants of ~ Badgastein, 5500 0.17-0.60 *0.5 - 2 3 - 27 (peripherie) Inhabitants of Badgastein 800 0.67-2.7 2 - 8 13 - 122 (center) Bath attendants 150 1.0 -5.0 3 - 15 20 - 225 Thermal Gallery administration 30 0.67-6.7 2 - 20 13 - 302 personnel

Thermal Gallery 10 1.8 -12 9 - 58 36 - 5U0 doctors, inspectors Thermal Gallery mi- 10 30 -uo 120 - 160 600 - 1 800 ners, trainleaders JU t

Behavior of Ra and uPb in the aquatical environment of the first Brazilian uranium mine and mill. E. Penna Franca, E.C.S.Amaral, M.G.Stoffel. Institute of Biophysics - Federal university of Rio de Ja- neiro.

The first Brazilian uranium mine and mill will start operation in 1981, on the Pogos de Caldas plateau, in the central state of Minas Gerais. The uranium mine will ex- ploit an open sky pitt. The site licensing procedure and the pre-operationai environmental surveys indicated that the critical radionuclides in the region wilj be: 226Ra> due to the tailings pond liquid effluent, and ^1(-)Pb, due to radon dispersion, fall-out and accumulation on the ground. As part of the environmental studies it was decided to carrv on laboratory experiments on the behavior of ^2oRa and 210pi)/ on their interaction with local waters, particles in suspension and bottom sediments and the subsequent leaching by river waters. The results demonstrated that Ra and Pb, in contact with water and sediments or particles in suspension, rapidly reach equilibrium. The distribution coeffipients range from 103 to 104 for 225Ra and from 104 to 1CP for 2I0 The granulometry of sediments slightly influences the distribution coefficients for 210pbf 'DU-^ not significantly for 226RS. NO correlation was found between the distribution coefficients and the organic matter contents of sediments, for both radionuclides. ihe^-^^Ra leaching of contaminated sediments £>y river waters was fast and appre- ciable (from 16 to 64% under the experimental conditions used). It was influenced by the ratio water volume/sediment mass. No measurable ^lOpfc, leaching was detected. Other experiments are under way to observethe influence of chemicals, expected to be present in river waters due to the mill operation, on the leaching of 226R3 and 210pfc retained in sediments. Based on the data obtained, a model was proposed for la and 210PJ3 transport in the local rivers.

79 - HATUBAL BADIOACTIVITY IH POOD-STUPPS EHOM HIGH FATUEAL SADIOACTIVITÏ AREAS OP SCöTHEBN DJEIA

B.I, Ltlit and 7.K. SfaukJ* Air Monitoring Sectie» Bhabfaa Atomic Eese&rch Centra Bombay-400 035 India IE the MS-HI, 1978 conference, some data oa naturally occurring radicmjclides in variety of food samples collected froa Bombs/ area ws; pr^seated (1). Thees samples were collected from hinterland of city of Bombay having noraal radiation background arsas. A «j-c-reteh OÏ' aaout 250 iciloastra long and about 0«5 kilometer iz? width in the states of Kerala aod Tamil Nadu in India havs 2>or*3.3ite deposits aontainiry? principally thorium to the extent of ö to 10 %. Thii; area is considered as one of the high natural radioactivity areas of the world. A number of food-stuffs, which s-are actually grown in this area, were collected and analysed for their potasaiUE-40, rsidium«226 and thcrirun-228 content by usiii^ the ray spectrometric techniques outlined in earlier publication These reacl«;e are presented and discussed in this paper»

Samples•fere collected at Sfenavalakuriehi, Chavaras Ponnana ££d SgeMsJtara' ursae in the high radiation background areas. It is fc-oad 'that most of the fruit vegetable samples such as bri-njals, anake-gousd and fruit samples liks plant«ain and papaiya collected in these areas haè jsarginally higher 22ÓPJ, arïj 228^ COatent (10-20 r.Ci 1%"^ wat waight)» Cucuaibsr and colocasia (root vegetable) from 22S Caavara z-egion had soncentrations of 8£> pCi 22&j>c g^ 296 pCi Tti %""' wet weight respectively» Coconut samples were analysed in three parts J outer case (goaiewhat soft fibrous material-epicarp,), inner case (middle hard cosponent - a shell or pericarp) and th» kern©! (white part inside shell used for eating and manufacturing coconut oil). The outer case and the shell had'rauch higher concentrations of 22gHa and 228Th (100-800 pCi per piece of normal size coconut weighing about 800-1000 gms). Concentrations of these isotopes in kernel were normal. The levels of these isotopes in coconut samples collected in Bombay region were also normal (few pCi per piece), fhe findings on coconut samples from Kerala areas are similar to those reported from Brazil nuts (2). These results will have Important bearing on natural radiation environment because the outer case is widely used in coir industry (most of the coir in India comes from Kerala region) and hard shell is used as fuel or its a«h as tooth-pow&orby villagers. The content of 40K was also somewhat higher in these samples. 22SL It is known that tia is the oain long-lived radionuclide of thorium series absorbed by the plaats growing in monozide bearing regions; Its subsequent radioactive decay results in the buildup of 22STu. Tn» results art discussed in terms of soil-conditions» growth-pattern, natur» of root system for these crops. REFERENCES 1. Ie lit, B.Y. and T.V. Bamchandran (1978), natural Radioactivity in Indian Pood-stuffs, The Natural Radiation Environment III, Boole of summaries, Houston, Texas, U.S.A., p. 123. 2. Smith, K.A. (1967), Comparative Distribution of the Alkaline Earth Elements in Brazil Nut Trees : Agricultural Research Council Hadiobiological laboratory, Annual Report 1966, ARCRL Ho. 17, Wantage, Berks, ÏÏ.K. p. 20.

- SI Tl.'

DITSHHAL EXPOSÖEB AT THE HIGH BACKGBGO5D AEEAS

A.C. Jaul, P.M.B. Pillai, T. Veteyudban* and K.C. Pillai Health Physics Division Bhabha Atomic Beaearch Centre Bombay-400 085 Apart from the high external radiation field prevailing, people residing in the high background areas are subjected to additional exposure by way of ingeetion and inhalation. The important pathway of ingestion is identified as intake through food and drinking water. The mole food (thali) served in a canteen and drinking water collected from the high background area show Ha-228 activity ae presented in table 1. Table 1 Ea-228 Iff FOOD AMD DBI5SDTO WATER

Article Ra-228

Whole food, Veg., 1.3 kg (canteen) 65 + 13 P« Drinking water Plant (well) 3.6 +.0.05 pCi.i'-1 Chinnavilai village (well) 7.8 i 1.2 " fencbayat supplied 3.3 +.0.04 "

Considering 2 meals in a day with a drinking water Intake of 2*5 litres, the total Ingestion of Ea-228 would work out to nearly 150 pCi.d""^ of which water would constitute less than 10 %. Another inportant pathway of internal exposure* i« the ingestion of active raw sand itself. This aode of exposure is inadvertent, but mostly unavoidable. It is obvious that children are most au«ceptible to this type of exposure. The radionuclides in the ingested raw sand would get partly aetabolised giving rise to long term deposition in body tissues. A manifestation of this could be observed in the fowls sampled from the area. Fowls by virtue of their eating habits peck on the ground and in the process ing«3t the active mineral along with the food. Hurt of the ingested activity gets metabolised which results in the deposition of radium

•Indian Bare Earths Ltd., Kinerals Division, Jfrnavalakurichi . 629 252 Tamil Sadu. ia bone* Gamma spectra of the gizzard content, collected from the fowlsi show photopeaic distribution similar to nonasite; however only Ha-228 shows up in the spectra of bone. Data obtained with respect to the analysis carried out on 2 fowls are presented in table 2. Table 2 Ea-228 ACTIVITY IS FOWLS

Sample Ba-228 pCi.kg-1

1. Bone 1200 • 180 Gizzard content 14600 7 1300 2. Bone 1852 + 201 Gizzard content 2597 T 304

Surface raw sand activity in the area where the fowls are fed is found to be 5 i 10^ pCi.fcg-1, which gives a transfer ratio of 0.003 to the bone of the fowl. The apparent difference in the activity of the gizzard content is not reflected in the bone depositioni as the latter is a cumulative effect which represents an average situation. The fowls do not show any significant activity in the flesh, however egg shells indicate the same specific activity as that of the bone» It is recognised that apart from radium, other activities such as U, Th, Fo, etc present in monazite may also get metabolised and deposited in different body tissues contributing to the total dose. Dose due to inhalation of radon, thoron and decay products could also be significant in the area. The levels are found to be 10"~10 ana iQ-9 uCi per cc of air for radon and thoron, respectively, inside dwellings* Data obtained on the radionuclide content of urinary excretion of children belonging to two age groups in the area are discussed. The paper strives to present an integrated approach to evaluate the significant intakes for estimation of the total dose to the people residing in the high background areas. I'd

THE SURFACES GEOCHEMISTRY OB UEAHIUM AHD THORIUM SERIES RADIGNUCLIDSS OVER THE ENH4KCZD KATUHAL BADIOACTITITY

BT.A.Titaeva, Y.I.Maslov, A.I.Tasieaev, I.I.Suktomova USSR, Hosed* State University, Komi Branch of the Academy of Science

She radionuclide geochemistry under surface conditions will be determined by a namber of factors: 1) concentration of radionuclides in. rocks and their products of disintegrations as veil; 2) the form of radionuclides occurances in rocks and their resistance to weathering; 2) radionuclides transporting medium; 4) the fora of radionuclides when, transported; 5) physico-chemical conditions of their fixation and form their presence in soils. We have studied uranium» thorium and radium isotope geochemistry in the European part of the USSR. This area rocks possess Th enhanced concentration and Th/U=(l-100) n. They contain up to 20% of a mobile Th and nearly 5% of a mobile U easily leached by Ha2C0, 5% solution. There have been noted the unusually high Th concentrations in water up to n 10 g/1 and Th/U higher than 3 and some- times up to 50. The field experiments of ionexehange co- lumn have shown the presence in waters studied of both cation and anlon TJ and Th forms, Th anion form predomina- ting. With a view of studying migration there has been used a technique of radioactive disequilibrium in the uranium and thorium series. As uranium geocbemieal indicators there have been used 2^o/2^8ir activity ratios, for thorium 228Th/2^2Th being used. The significant part of radio-, nuclides water migration, inf lunces radioelement isotope composition in soils and bottom sediments. 2^hj/2^8ü and 22^h/z^21ih values activity deviate from equilibrium both sides depending om U and Th fragmental or aorbtien form of Dredominanco» - 84 - In the upper accumulative horizons of mountain- -tundra soils element sorbtion forms predominate, waTinmii) concentration coinciding with, iron «a^^CTi concentration, uranium accumulation in a humus horizon depends on redox conditions. Generally its concentration correlate with FeO/FepO,. In eluvium horiaon there has been noted £h leaching from mineral fragment soil fraction, its concentration increasing downward. Uranium leaching has been noted in the soil profile lowest horizons. Radium in nearsurface rock zones and soils as well is much higher than that of uranium equilibrium concentration. It is connected with radium exolution from deeper horizons and its successive sorbtion and uranium leaeiing as well, uranium enriched humus horizons are the excep- tion. 23°Th/258U ratio characteristically alike with that of Tte/ ^U. Hence, radionuclide surface geology is successfully followed by making use of disequilibria in IT, Th series. 02T SATOEAL TEE EOS SH?IHG AES&S

ÏÏ.C» Mishxa, L,ü, Joshi and &* 3athe Air Moni-soring Section iïfe-abh» At aasic Heaeareh Cen Bombay-400 085 India

rj&rried out aï th* üot .spr-i&ga ia 7usa9 a ia --a- district of Suiaj-e.i; Star^ vadioated caüu hot,

-uv.-risd yy.t- recent],7 i^i tb.ö-5? area3 shew r-a=li.cact-iv.Lty doaes in zh-, :a:'.;je of 0,4 t-o 2.>2 32?:/br; tas highest cose bsirg ;«sr the cenxral pu.'icU '?!"•«; ö,02:i; rat* dscr&«35s s-s ons procsi-fifj -•./-•/ fros the ponds» It ba.? been observed 'feat at Godhra ïailway etasioa. i>. diaiane« of SJIS from the araa of ponds? the dose rato drops down to 0.01 s Studies hav? slso beaa carried out on gioenec-dcal beaaviour of uraaiuci arid r-adiuaa in the region^ The region y^ves unique infomaxicn about geochandstïy aad tsansport of natural radicactivity. The preliminary measure^snts iiave indicated renar-cacls anos-aloua bebarifflir of U23S and U234 isotopes, the activity ratio» ex TJ23A ,-U238 are however varying is. she racgs of 2.23 to 2»76 -t;ich are oonsiderably higher aa cconjarsd to about 14 % excess of U2-*-4 obtained in eoaatal sediiEents and marins organisms. The radium concentrations in the region have been found to yary from 10-23 pCi/Iitre, The higher concentrations of radium observed in the region can be attributed to constant leaching of radium by water from uranium ore body which may be present underground in adjoining areas. Implications of high Ea226 ^ terms of radiation hazards to general population have been discussed. IN7BSTIGATIOTS OS HDMA5 POPULATIONS RBSIDI5O Iff HIGH BACKGHOJHD RADIATIOff AREAS OF KEHALA AHD ADJOIBIUG HBGIQHS : CYTOGEHETIC STUDIES.

K.?. George, K.V. Aravlndan, B. Joseph, M.V. Tbaapi, 7.D. Cberiyaa, C..J. Kurien, 7.B. Shah and £. Sundaram Vooazlta Survey Project laboratory (Medical Group, Bhabha Atonic Research Centre); I.JT.M.C.H. Unit, ffeendakara, Quilon 691582, Kerala, INDIA.

In continuation of our efforts to evaluate long tern effects of chronic radiation on nan, chromosomal analyses have been initiated on human populations residing in the monasite bearing high background radiation areas of Kerala and adjoining regions. The demographic and dosimetric aspects of this population were reported earlier* Orer 496 samples have been cytologically analysed. These samples were drawn from various sources and includes newborns, their parents, samples from low background and high background areas. Blood culture techniques have been employed in chromosome work and the samples were processed at 50-54 hr. cultures. Cells haring well spread metaphase chromosomes and 46 centromeres were only considered for cytologies1 screening. Among the 457 samples analysed so far, 85 samples came from new boms and the remaining from adults. Of the 85 samples of newborns, 47 were born to mothers who are not residents in the high background radiation area and 38 were born to mothers who are residents in the region* The aberration frequency in both the groups were similar. The 372 adults included in the study could be divided into two groups - 247 persons were residents of high background radiation areas, which include 62 persons working on monazite sand and the remaining 125 persons were residents outside the high background region. The frequency of dicentries and rings per cell in the control population was 7 x 10~* and 12 x 10* in the high background radiation population. SCE data on 41 individuals from control and 32 from exposed population did not indicate any significant differences between these two populations. Implications of these findlags will be discussed. THE RADIATION EXPOSURE OF MAN FROM RADON AND THEIR DECAY PRODUCTS IN THE INDOOR ENVIRONMENT

F. Steinhausler and E. Pobl Division of Biophysics, University of Salzburg A-5020 Salzburg / Austria

Internationally growing concern is being expressed about the radiation exposure of large population groups from elevated levels of natural radionuclides. Although these nuclides - apart from cosmic rays - were the main sources for the natural radiation environment (NRE) all through the evolution of man, only during the last ten years attention has focused on the health risks associated with the exposure to the NRE. Since man spends up to 90 % of his time in rooms, in most countries it is the indoor environment that causes the major contribution to the total dose from the NRE. Of particular interest are the decay products of ^"Rn and ^ Rn, since in parts of the respiratory tract they can cause the highest radiation burden from all naturally occuring sources. Technological developments in general and specific local conditions in some areas can introduce even stronger sources of radon daughters into man's environment: a) several industrial activities (e.g. mining in general, aluminium- and fertilizer-production, coal fired power stations) result in the accumulation of large amounts of unwanted waste products. Simultaneous need of equally large quantities of raw materials for construction purposes, paired with concern about environmental protection suggest the large scale use of these industrial by-products, e.g. as building materials. Unfortonately many of these new, economically and technologically advantageous i&ais? rials have been found to contain highly elevated levels of Ra and "2 respectively ^°Ra (e.g. India, Brazil). Unfortunately.the radiobiological information on the effects of inhaled radon daughters available is scarce, partially contradicting and non- conclusive. Latest laboratory experiments with rats demonstrate increasing effectiveness of lung cancer induction (per unit exposure) due to decreasing radon daughter exposure below levels of 290 WLM. In other studies on the same animal it could be shown that there is also a statistically significant decrease of survival time at an exposure level of about 300 WLM. However; lung tumor frequency increased significantly only under simultaneous high ore dust concentration as levels were raised from about 320 and"6U0 to 2560 WLM. The solely information available for man are the lung cancer epidemiological studies carried out on US- and CSR-uranium miners as well as on several groups of non-uranium miners. These results show increased lung cancer incidence only well above an exposure of several hundred WLM. Large uncertainties are involved in the dose assessment for the individual miner and quantitative information on other simultaneously present carcinogens and competing risks besides radiation induced cancer is lacking. Therefore risk factors derived from these studies differ by as much as a factor 2. Risk assessment for the general public based on the above data is problematic for the following reasons: a) with regard to the laboratory experiments, the differences in the radiation response between rat and man concerning cancer induction are unknown b) with regard to the miner epidemiologies, the validity of extra- polating from risk factors derived from a dust- and fume-pollu- ted mining environment to that of atmospheric indoor conditions in dwellings is highly questionable. In view of the importance of this problem several attempts are current- ly being undertaken at national and international level by regulatory and scientific committees in order to assess the risks associated with the exposure to one of the most widespread known carcinogenic pollutants in the environment of man.

ao TECHSOIOGICALiy KQDIPIBD BAH^AL BADIiTIOBS BXPOSORB

T.F. GESBLL Th» UniTeraity of Texas Houston, Texast U.S.A. TECHNOLOGICALLY ENHANCED NATURAL RADIOACTIVITY IN A COAL- FIRED POWER STATION

Bauman A., Horvat Dj., Kovac J. and Lokobauer N.

Institute for Medical Research and Occupational Health 41000 Zagreb, Yugoslavia

A project was conducted to evaluate the impact of natural radioactivity from a coal-fired power station on occupationally exposed persons and the surrounding country side. The investigated coal used for combustion was an anthracite coal which in addition to higher uranium content ranging from 14-1500 ppm had an elevated amount of sul- phur 6-9% (1,2). The contamination of personnel and equipment with radioactive dust was considerable and remained unremove. The contamination of the surrounding country sj.de was detected while determining Ra-226, uranium and SO" concentrations in creek water which is released as waste water into the sea after passing through the coal-fired power station. The concentrations were determined upstream and downstream from the power station. Personnel monitoring was done by mutagenic analysis and control of Pb-210 in urine. The persons under investigation all spent their occupational life in coal-fired power stations and nowhere else. They and the control group were screened by a questionnaire consisting of demographic, medical, occupational and tabacco use data.

Results Fresh water from a creek entering the coal-fired power station (CFPS) had uranium under the detection limit, but a significant amount of Ra-226 i.H. 0.U7 Bq/1, originating probably from the soil 10 miles upstream. On reen tering into the creek the waste water from the CFPS had 0.35 Bq Ra-226/1, a high content of uranium - 950 yg/1 and 803.99 mg S0~ /I.

This paper is based on work performed under.International Atomic Energy Agency contract No 2346/R1/RB. The path of the creek ends 1 mile downstream from the coal-fired power station in an estuary where fresh and sewater mix. About 50 m further from the mixing point in the bay the level of radioactivity in saline water was 120 yg/1 for uranium and 0.100 Bq/1 for Ra-226 at a pH=5.8. In the suspended solids separted from one litre of surface sea water uranium was present with 590 pg and 0.636 Bq Ra- 226. The environmental impact must be considerable. Since at a distance of several miles fish is caught for commercial purpose and fed to the local population, or processed in several plants the level of radioactivity was of utmost importance. One specimen of pilikhardia clupea had 11.HO ug/kg of uranium and 2.60 Bq Ra-226/kg, another had 55.50 €q of total alpha activity, and one specimen of eel from the estuary had 100 ug U/kg and 0.85 Bq Ra-226/kg. Paralelly with environmental investigations personnel monitoring was done. Two groups of subjects were chosen. One consisted of non-smokers and the other were regu- lar cigarette smokers. Workers exposed to natural radiation in mining were excluded. The results are given in following tables.

Table 1. Pb-210 levels in urine and percentage of chromosomal aberrations in occupationally exposed persons to natural radiation in the coal- fired power plant (non smokers)

No. Age/ Years of PCi Pb-210/1 % chromosomal subjects years exposure urine aberrations 1 52 24 5.80 6.0 2 39 20 7.15 10*0 3 35 3 1.89 6.0 4 39 3 14.47 7.5 5 26 3 4.31 7.0 6 33 2 2.29 8.0

From all the resulrs the blank level of 1.05 pCi Pb-210/1 urine obtained from the control group was deducted. Table 2. Pb-210 levels in urine and percentage of chromosomal aberrations in occupationally exposed persons to natural radiation in the coal-fired power plant (smokers)

- 92 - No. Age/ Years of Mo ciga-pCi pb-21C/l %chromcsomal subjects _years exposure rettes/day urine aberra-. icr.s 1 39 10 5 4.75 3.C 2 35 7 3-5 1.89 8.C 3 28 6 20 0.7 3 2.C 4 31 6 20 0.37 4. c 5 26 4.5 20 9.89 4.5 6 39 3 5 13.12 n £ 7 30 2.5 20-25 7.1C 8 24 2 20 0.46 12 . C 9 43 2 20 2.15 10 27 2 20 0.5S -. c 11 34 2 50 3.27 5 . 5 The results No. 3, 4, i and 10 are the original vali es. The blank level of 1.05 pCi Fb-21C/1 was deducted frcr. all other values. All exposed workers shewed the same type of structu- ral aberrations as the control group i.e. breaks and gaps except nos 2, 8 and 11. Discussion

The coal-fired power station described in this paper is a complex source of conventional contamir.ats, SC,, heavy metals, benzo(a)pyrene and natural radioactivity. •" Before even approaching the problem of possible syne.rgis~: inside the coal-fired power station the question of the impact on the environment and occupaticnally expesec persons had to be investigated. The environmental impact was measured in fish several miles distant frcn the ccal-firec power station. No changes from normal levels of Pb-210 and chromosomal aberrations at background levels were fcund ir. cccu- pationally exposed persons. The changes were observed =t 100 mrern above the noramla background. From the fraquer.cy and type of chromosomal aberrations can be persur.ee chat the cytogenetic damages originate more from low coses of radiation them from chemical mutagens. Literature 1. R.C. Corey: I. How coal properties influence har.cilir.g and combustion. Chem. Eng. _8_5, 111-11S C197S).

2. R.R. Beven: II. Coal handling at the olant site. Chem. Eng. _8_5, 120-128 (197-8). NATURAL RADIOACTIVITY RELEASES FROM COAL FIRED AND GEOTHERMAL POWER PLANTS IN ITALY

R. Gragnani, G.G. Mastino and G. Paganin Laboratório Geochimica Ambientale, CSN Casaccia, CiVEN C.P. 2400, ROME 00100 Italy

Since 1973 new attention has been given to the use of coal for electric power generation. It seems actually the most liable energy source to satisfy the increasing energy demand in the short term, and may be aiso in the medium term (1). Coal world reserves, in fact, present a much higher reserve/ consumption ratio (about 200)* than both oil or natural gas (about 36), thus justifying a widespread attitude to consider the use of coal resources to fill the energy gap from oil to nuclear fusion (2). Sever problems are however posed by coal environmental impact, both from the chemical and radioactive point of view (3-10). If radioactive airborne releases only are considered, a large variety of studies has been carried out leading to somewhat contradictory conclusions (11-14). It seems in fact that the environmental conditions considered and the foodchain taken into account be responsible of such variability, as well as the model adopted to interpretate the transfer of radionuclides from the source to the environment (12,15,16). In Italy the CNEN Environmental Geochemistry Laboratory (EGL) has started a program to evaluate the environmental impact of various energy systems (fossil fuels, geothermal fluids) (17,18). In the framework of this program, a study on coal being used in Italy has been initiated, starting witti the evaluation of radioactive releases from thermal power plants. For that concern geothermal fluids, data on releases are also ready available. Italy produces only 30*£ of the coal used for power production, the remainder being imported from Poland and South Africa mainly. Italian coal is almost brown coal characterized by a low heath content and high ash resi- due. In the paper are given: - concentration of the most important natural radionuclides in the various coal minerals, ashes and fly ashes; - estimates of yearly released activities for various plants in production and for those in construction; oncentration of the most important natural radionuclides in geothermal fluids; - estimate of the yearly released activity; - estimate of the radiological impact for the populations living in the vicinity of the power plants, on the basis of the comparison with similar studies carried out in other countries. Similarly to the majority of these studies, such results are to be considered only partly significant of the radiological impact due to the coal energy production, as they should include also the contribution of the extraction, transport and possible treatment of the coal, as well as that of ash tailings and their"recycling. Finally it is discussed that in any case the radiological impact for both coal and geothermal fluids represents a limited portion of the overall impact (due to stable and radioactive substances) through the whole energy cycles. Anyway it has to be considered that for both coal and geothermal energy, technological development may strongly reduce the release of harmful1 substances (13,17). The evaluation of the radiological impact might therefore be considered as a tracer study to provide fundamental guidelines on which stimulate and plan technological application developments that may lead to a safer management of coal and geotherraal energy.

REFERENCES

1 - GABOR, D. and U. COLOMBO,1976, Beyond the age of waste, The Club of Rome Ed., Geneva. 2 - WAES.1977, Energy global prospects 1985-200O, Report of the Workshop on Alternative Energy Strategies, New York. 3 - HAMILTON, L.D.,1975, Health effects of air pollution, Proceedings of the Conference on Computer Support of Environmental Science and Analysis, U.S. Energy Research and Development Administration, Albuquerque, New Mexico, July 9-11, 1975. 4 - HAMILTON, L.D.,1979, Health effects of electricity generation, Proceedings of the Conference on Health Effects of Energy Production, Chalk River, Ontario-Canada, Sept. 12-14, 1979. 5 - BLOCK, C, DAMS, R. and J. HOSTE, 1976, Chemical composition of coal and fly ash, Proceedings of the Interna- tional SynposiuB on Development of Nuclear Based Techni- ques for the Measurement, Detection and Control of En- vironmental Pollutants, Vienna, March 15-19, 1976, IAEA Vienna, 1976, pp. 101-109. 6 - LYON.W.S.,LINDBERG,S.E., EMERY, J.F., CARTER, J.A., FERUSON, N.M., van HOOK, R.J. and R.J. RARIDON,1978, Analytical determination and statistical relationships of forty-one elements in coal from three coal-fired steam-plants, Proceedings fo the International Sympo- sium on Nuclear Activation Techniques in the Life Sci- ences, Vienna, May 22-28, 1978, IAEA, Vienna, 1979, pp. 615-625. 7 - COLES, D.G., RAGAINI, R.C., ONDOV, J.M., FISHER, G.L., SILBERMAN, D. and B.A. PRENTICE,1979, Chemical studies of stack fly ash from a coal-fired power plant, Environ. Sci. Techno1. ^3 n.4, 455-459. 8 - TITTERTON, E.,1978, Pollution, environmental and health hazards of fossil fuels, Report ANU-P-727. 9 - LYON, W.S.,1977, Trace elements measurements at the coal fired steam plants, CRC PRESS, Inc. Bocae Raton, Florida. 10 - UNEP,1979, The environmental impacts of production and use of energy - Part I - Fossil Fuels, Report of the Executive Director, Nairobi, Sept. 1979. 11 - KOLB, W.,1978, Die Emission radioaktiver Stoffe mit der Abluft aus Kern und Steinkohlekraftwerken, Report PTB- Ra-8, Feb.1978. 12 - McBRIDE, J.P., MOORE, R.E., WITHERSPOON, J.P. and R.E. BLANCO,1978, Radiological impact of.' airborne effluents of coal and nuclear plants, Science, 202, 1045-1050. 13 - BECK, H.L., GOGOLAK, C.V., MILLER, K.M. and W.M. LOWDER, 1978, Perturbations on the Natural Radiation Environ- ment due to the utilization coal as an energy source, Proceedings of Natural Radiation Environment III Inter- national Symposium, Houston, Texas, April 23-28, 1978 (in press). 14 - USEPA,1977, Radiological Quality of the Environment in the United States, USEPA Report 520/1-77-009. 15 - CAMPLIN, W.C. and J. HALLAM,1980, Assessment of the radiation exposure from the radioactive material released from the stack of a 2000 MWe coal fired power station, Proceedings 5th International IRPA Congress, Jerusalem Israel, March 9-4, 1980, vol.Ill,pp. 153-156. 16 - 0KAM0T0, K.,1980, Effects of the foodchain in radioacti- vities released from thermal power plants, Proceedings 5th International IRPA Congress, Jerusalem, Israel,

- 96 - March 9-14, 1980,' vol.Ill, pp.157-160. 17 - MASTINO, G.G., 1979, Natural radioactivity Levels in releases from coal-fired power plants in Italy, Pro- ceedings of the Seminar on the RadiologicaJ Burden to Man from Natural Radioactivity in tne Countries of che European Communities, LeVssinet, Paris, Dec.4-6, 1979, C.C.E. (in press). 18 - MASTINO, G.G.,1979, The radiological impact of geothermal energy, Proceedings of the Seminar on the Radiolo- gical Burden to Man from Natural Radioactivity in che Countries of the European Communities, LeVesinet, Paris Dec.4-6, 1979, C.C.E. (in press). . ium in Waste Water from Coal Mines and Other Sources is tbe Federal Republic of Germany

I. Grans, V. Fubrmann, E, Weller and E. Wollesbaupt

Institute of Water, Soil and Air Hygiene of tbe Federal Health Office, Berlin (West), Federal Republic of Germany

In tbe course of a pre-operational radiological survey for a nuclear power station concentrations of more tban 1 pCi/1 of radium 226 and 228 were detected by local authorities in tbe River Lippe which receives waste water from coal mines in tbe German Ruhr district. While concentrations of this magnitude are not uncommon in natural waters relatively high radiation doses may be calculated, wben radioecological models used in the evaluation of radioactive emissions from nuclear power stations are applied for calculation of doses resulting from these technologically enhanced levels of natural radioactivity.

A research project was set up to investigate radium emissions from all coal mines in the Federal Republic of Germany as well as from other sources that are potential radium emitters e.g. pbospbate fertilizer industry.

Until now concentrations from less than 1 pCi/1 up to a few hundred pCi/1 of radium 226 bave been found. The emissions calculated from these data range from 1 mCi and less to 1 Ci per year. Due to tbe chemical composition of tbe waste water from mines a large fraction ot tbe radium emitted is bound

-- 96 to sediments in tbe receiving water body» wbicb axe spread on pastures by yearly floods. Measurements of radium in tbe terrestrial and aquatic food chain were started to validate paru&aters used in radioecological models. Besults ot tbe investigations and tbe Implications for an evaluation of risks are discussed and compared to radiological consequences of radium concentrations in tap water and bottled waters.

99 - w-A 3

STUDY 09 BADOH CONCBNTEATIOr HEIEASED INTO THE ATMOSPHERE DOE TO BURNING OP NATUBAL GAS

Jf.C. Subba Banu, T.S. Muraleedharan and K.G. Vobra Air Monitoring Section Division of Badiological Protection Bhabha Atomic Besearch Centre Bombay-400 085 Uee of natural gas aa a fuel both for industrial and domestic purposes can be expected to contribute to an increased exposure of the population to natural radiation, lieaaured radon concentrations in natural gas at the wellhead have been found to vary from 10 to 1500 pCi/litre (Gesell, 1975). In this paper an attempt has been made to analyse the results of the measurement of radon concentration in air in Trcmbay where the Tata Thermal Power Station (TTPS) and the Bashtriya Chemicals and Fertilisers (BC?) which use natural gas as fuel are located. South Site Gate Terrace (SGT) and Modular laboratories Terrace (Miff) in B.A.B.C. are the two locations selected for the measurement of the concentration of short-lived radon decay products in air. SGT is about 500 metres south and Miff is about 2 1cm. north- east of TTPS. The measurements are spread over four months starting from February to Hay 1979. Atmospheric aerosols are collected on Millipore filter paper (type AA) by drawing air through the filter paper using a suitable pump at a flow rate of 25 1/min. The filter paper sample is counted for =C activity. The activity contribution from thoron decay products is subtracted by following the decay of the sample* The resulting data is fed to a computer for analysing for Ba-A, Ea-B and Ra-C concentrations in air. Badon concentration can be calculated by assuming equilibrium between radon and Ba-A. The average concentrations of the radon decay products at the two locations are given in Table 1. The data indicates that TTPS; Table 1. Average Concentrations of Badon Decay Products at SGT and Miff for the period from February to May 1979* Ba-A Ba-B, Ba-C_ Location 5 3 (pCi/m ) (pCi/«3) (pCi/. ) SGT 1018.4 136. t 55»? MUZ 433.2 46.0 29.7 eculd be the source of radon activity in the air. As one noves away from TIPS, the radon decay products reduce in concentrations due to dilution. Build-up of radon decay products in tae atmosphere depends on time, distance and topography of the location. Correlation studies with wind direction show that the sources of radon are likely to be TIPS and HC?. Sadon concentration measured in the Trotubay region earlier^ when natural gaa was not being used aa fuel, varied from 90 to 320 pCi/a3 (Subba Eaau and Vohra, 1969). The rate of discharge of radon through the TïïS stack due to burning of natural gas can b« computed from the concentrations jaea3ured in air. Shirvaiiiar and Abrol (197B) have woyketi cut tho dilution factors for different conditions of release of radioactivity in air. Although the stack height of TTPS is about 76 metres, for the topographical conditions existing in the 'Ironibay ragion and -the measurement of radon levels at ÏÏLT (17 inetrs8 high)» the ralsase can be considered aa the ground level release and the measured concentration as the ground level concentration. Por a wind apseö of 2 ffletrss/sec. and the atmospheric condition in between slightly unstable and neutral and a consumption of 0.9 Billion m3 of natural gas per day (Oil and Xatural Gas Commission, 1979), the radon content of the natural gas has been eatliaated and compared with the measured concentration of 182 pCi/1. using a conversion factor of 9 «rad per pCi hour per litre as specified in the UHSCEAB Seport (1977), the dose rate in the lung at KKE can be found to vary from 1.8 to 132 m rads/year. If we use a quality factor of 20 for =C radiation, then the does equivalent varies from 0.04 to 2.6 rema/year. As given in the UKSCEAB Eeport (1977) the dose equivalent due to breathing of background Sn-222 decay products varies from 0.02 to 0.6 rems/year. According to ICRP recommendations (197?) the dose equivalent limit for the limitation of nan-stochastic effects on members of the public ia 5 rems/year. SEPEBENCES Gesell T.P., 1975» Health Physics, 29, 681. ICEP, 1977, Hecommendations of the International Commission en Eadiological Protection, Riblicaticn No. 26. Oil and Natural Gas Commission, 1979, Personal Communications. Shirvaikar V.T. and Abrol V., 1978, BAHC fieport Bo. 1-503. Subba Banu «.O. and Vohra E.G., 1969, Tellua, 21, 395. DN3CEAE, 1977» Source» and Effects of Ionising Eadiation, united Nations, Sew York. I/-A ii

ENERGY AND ENVIRONMENT

G. CAS ALE and R. KIRCHMANN

Department of Radiobiology, Belgian Nuclear Research Centre

(CEN/SCK)

3 - 2400 MOL (Belgium)

The purpose of this article is to examine the impact of pollution at the different stages of exploitation of the primary energy sources. According to Holdren the social and environmental constraints much more than fuel supply will be the factor limiting the energy utilization rate by our civilization for the next hundred years. Energy sources can be divided on one hand in ncn-rencv/able raw materials (coal, oil, natural gas, fissile and fusion materials) and,, on the othex' hand, in renewable sources (hydraulic, solar, gsothermal, wind). With regard to the appraisal of the environmental effects, the different steps of the fuel cycle have been considered : production or extraction, transport, treatment (enrichment, refining, purification...). The nuclear debate has led the responsible authorities to make a comparaison of the health and environmental hazards associated with the primary energy sources that are available or to be developed. Moreover the radiation dose rate from airborne releases of radionuclides are compared for geothermal, coal-fired and nuclear power plants.

102 Table 1.

Chemical effluents released (kg.hour ) and radio-

elements released Qaci.hour ) by model 1000-MW(e) power plants us;mg .different fuels

Effluents Coal Heavy oil Natural gas particulates 671 267 67 5 5 5 C02 9.1O 7.1O 6.1O - S02 8340 15000

SO3.H2SO4 - 250-500 - CO 208 1.5 1.7 Methane ) 123 183 ) 66.7 Polycyclic ) Hydrocarbons ) 3.1O~3 3.1O~4

Vanadium(V2O5) - 30 - NOx 3750 834-2835 - Radium - 226 .3.3

Radium - 228 2.1

Thorium - 232 3.3 Lead - 210 8.1

Polonium - 210 8.1 Table 2.

Radioactive effluents released (uCi.hour" ) by a typical pressurized water reactor (PWR) and a typical boiling water reactor (BWR) of a nominal power of 1000 MW(e).

Effluents . PWR BWR

Liquid without 43-S5OO 25-2150 tritium

Liquid tritium 55.103 - 86.103 9.1O3 - 14.103

Gctseous noble 3.7.106 6.1O6 gases

131 Gaseous I2 28 - 1800 2.8 - 93 REFERENCES 1) J.P. HOLDREW, "Energy Resources" Chapter 5 in Environment, 2nd Ed.r Ed. W. Murdoch, Sinuar Associates, Sunderland, Mars(1975). 2) Conférence Mondiale de 1'Energie - Enquête sur les Ressources Energétiquüs 1974. 3) B.G. BLAYLOCK and J.P. WITHERSPOON, "Dose estimation and Prediction of Radiation Effects on Aquatic Bota resulting from Radioactive Release from the Nuclear Fuel Cycle" I.A.E.A. - SM - 198/5, 1975. 4) Commission d'Evaluation en matiêre d'Energie nuclëaire- Rapports techniques, Groupe VI, "La Santé", 2° partie, 1976. 5) A.J. ELLIS, "Geothermal Systems and Power Development". American Scientist, 63 1975 510-521. 6) L.A. ILYIN. V.A. KNIZKNIKOV, R.M. BARKHUDARD, "A relative risk estimation of excessive frequency of malignant tumors in population due to discharge into the atmosphere from fossil-fuel and nuclear power stations" - I.R.P.A. Proceedings, vol. 1, n° 410, Paris 24 - 30 avril 1977. 7) R.C. AXTMANN, "Environmental impact of a Geothermal Power Plant" Science, 187 (1975) 795 - 803. 8) J.P. HOLDREN, "Adequacy of Lithium as a Fusion Source" UCID-15? 53 Lawrence Livermore Laboratory (197*1) . 9) Commission d'Evaluation en matiëre d'Energie nuclêaire- Rapports de Synthese, Mars 1976. 10) J.P. HOLDREN, T.K. FOWLER and R.K. POST, "Fusion power and the environment" UCRL-76911-June 2,1975. 11) J.P. Me BRIDE, R.E. MOORE, J.P. WITHERSPOON and R.E. BLANCO "Radiological Impact of Airborne Effluents of Coal and Nuclear Plants" Science, 202, n° 4372, 1978.

- 105 - BHAVCKD BXPOSJHIS f o IATUBAL HADIATICI iT n UDIA.

B.T. Zalit, T.r. Sfaukla, t.T. Ramecbaxxlran and U.C. Mlsbra Air Monitoring Section Bbabba Atomic Beeearcb Oantr* Bombay-400085, India aan ia azpoaad to natural radiation tram coamlo xmya and occurring xadioouolidaa la «oil, air» water and food. There ara other aoureaa dua to technological developments which enhance the expoaure to natural xadiation. In thia paper, two aucb human actiritiea contributing to technologically enhanced natural radiation are conaidered. Tbeae are : (i) utilization of coal as an energy source (ii) use of phosphate fertilizers. Coal-fired plants for electricity generation in India and other heary industries use nearly 73 MT of coal annually. The gaseous and particulate combustion products from thia coal burning at* discharged into the ataoaphere through stacks. These effluents, containing natural ladioisotopes of uranium and thorium series and pctassium-40 present in coal, get dispersed and deposited aainly within a circule of 500 km. radius around the plant. Small scale industries, railways and domestic coal burning consumed 27 KC of coal during 1977-78. Howerer, these sources bare not been considered for evaluation in view of their localised influence. Coal samples from various collieries and coal an£ flyaah samples from 23 thermal power stations spread all over India were analysed for their radioactivity content using ganaa ray spectronetric techniques outlined in an earlier publication (i). Avexage concen~ tz-tions of coal and fly ash are given in table 1. The assessment of radiological impact baa been made using assumptions ani $axametere gi.en in OTSCBAB (1979) (2) with proper corrections for population density for India. XABIS 1 Average natural radioactivity concentrations in coal ana flyash aamplee collected during 1977-80 (pGi/g)

Badionuelide Coal ?ly-ash

0.65 2.1 228_ xn 1.04 3.4

2.23 10.1 Aospbat* rock» and apatite deposits uaed ia th* saailBctur* of pho«pb**ii fertilisers also contain natural radioactivity af uranlus and thorium aeries, fertilisers used ia agriculture contain radius-226 and lts daughter produeta and potassiua baatd fertilisers contain potassiua-40. A large number of pboapbatic fertilizers «ara analysed ualng gaas* apeetrometrle techniques* Aa results on thaaa aaasurraents ar* aumaarized In tabla 2. IABM 2 fctursl radioactirltjr eontanta af phoaphatic fartllisara

Zjrpa of fartiUsar 226^

Singla aupar pboaptaat» 2290-7220 170-490 40-1850 Tripl* aupar phoaptaata 2890-9660 46Or87O OD»-1130 Boek phoapfaatt 900-36670 80-3060 200-2430 BI 1—miw» ptaoapbata 1330-3600 130-660 250-800 m fartillsara 90-1680 70-1680 1700-130,001

• JTot datactabla In oaleulatinc tha axteraal radiation doaa» only xadioactirity tram phoaphata fartilixara baa baan eonaldarad. Tor tha praaanfc papa» tha rica« wbaat» adllata and mxgtr oana cropa coraring an araa of 90 z 106 naotaraa of 142 x 106 haetaraa of total agrloultuxal araa «ra eonaidarad. High yialdiag variatiaa of rica and «baat on irrigatad land ara exaalnad bacauae thaaa cropa, undar irrigatad condities*» raquira higher doaaa of fertilise». Since -theee radiation doeea ara calculated for the ree naam i led •axlaai doaea of fertiliaer ua* ia India, all tb* radiation doaea du* to actual fartiUsar us* for other crops under noraal and non-irrigated aoila «ill be below the doses oaleulated in this paper. Badiation dosea to the faster* bar* been eatiaated by using gaasm doa* rate values at ana aeter giren in 0I3CIAB (1977) report for the** isotoges with corrections for distribution in soils (3). *

1. lalit, B.T. and I.T. BaMehandran (1976), natural and BtUout Itadioactirity in Typioal Indian Diet, BarlronaMBtal Quarter!/, Beport JUSL-306, Z-31. 2. OB903UB (1979), Technologically •odified Bxpoaurea to natural Badiation t A/AC-82/B-358, 18th April 1979» United nations, lew rork, 3-16. 3. OBaCBftl (1977)» Source* and Bffecta of Ionising Badiatian, B Bfctural aouroa* of BwUlation, Qnlted BaUoaa, Baw Tork, «9-91

in; U-A 5

An Interccwpari«on of Natural and Technologically Enhanced Background Radiation Levels in Micronesia

N. A. Greenhouse and R. P. Miltenberger

Safety and Environmental Protection Division Brookhaven National Laboratory Upton, New York 11973

The United States Pacific Nuclear Testing Program resulted in local and regional fallout contamination of islands in the central Pacific basin, in an area which is generically known as Micronesia. Most of the contamination affected the Northern Marshall Islands of eastern Micronesia which either served as the actual test sites or were in relatively close proximity to them. Since all of the Marshall Islands are low coral islands or atolls, the natural radioactivity content of the soil is among the lowest on earth; and the natural radiation environment is dominated by the contribution of cosmic rays. In contract, the high islands of the Caroline groups to the west of the Marshalls are characterized by volcanic soils having a significant complement of radionuclides in the uranium and thorium chains. Sev- eral field trips to Micronesia between 1975 and 1979 afforded opportu- nities to study the natural radiation environments of the coral atolls of the Marshalls and several high islands in the Carolines; and to evaluate'the contributions of fallout fission and activation products to the inventories of soil radioactivity in these locations. Analyti- cal methods included in situ gamma spectrometry and exposure rate measurements with pressurized ion chamber survey instruments. These methods were supplemented by laboratory analyses of soil samples. The results of these studies indicate that significant contributions from radioactive fallout can be easily evaluated on coral islands. In contrast, however, the higher natural radioactivity content of high island soils, and the greater distance of these islands from the test areas combine to make evaluations of local fallout contributions from U. S. Pacific tests indistinguishable from the multinational contributions of world-wide fallout.

Research carried out under the auspice of the 0. S. Department of Energy under Contract No. DE-AC02-76CH00016.

lG8 U-B i

RADON AND RADON DAUGHTERS IN PUBLIC, PRIVATE AND COMMERCIAL BUILDINGS IN COMMUNITIES ASSOCIATED WITH URANIUM MINING AND PROCESSING IN CANADA R.S. Eaton, Atomic Energy Control Board, Box 1046, Ottawa, Canada KIP 5S9

In 1976, radioactive contamination from industrial operations was discovered in the town of Port Hope, Ontario. A Federal-Provincial Task For-:e was established to deal with the problem and to search for similar contamination in other places. Since then it has been systematically surveying housing and other public buildings and taking remedial action in the towns of Port Hope, Elliot Lake, Bancroft and Cranium City. The primary criterion for remedial action is a radon daughter concentration of 0.02 WL with a radon equivalent used where necessary, prompt action is undertaken if the level is greater than 0.15 WX from a single grab sample. More detailed investigation of the premises is undertaken if a grab sample indicates a reading in excess of 0.01 WL. A log normal distribution is assumed for each individual building and a three sigma test is applied to borderline measurements to assist with decision making. The first site. Port Hope, has been the location of the processing of uranium ore since 1930, first for radium and since the mid 1940's, for uranium. Haste raffinate and used building materials have been found throughout the town. Of 3,000 buildings surveyed, remedial work on about 450 houses and commercial units produced 105,000 tons of low level waste. The other three sites are uranium mining communities in which there is some contamination in the form of waste mine rock. However, the bulk of the problem has been due to natural radon (see a companion paper by A. Scott-DSMA/ACRES) and decontamination through the removal of the source is not feasible. Some 3,600 premises have been surveyed and remedial work is in progress or completed on about 260 units. There is no significant contribution to radon daughter concentration in buildings from radon in water or from uncontaminated building materials. At NRE III, in April 1978, Knight and Makepeace of the AECB presented a paper on the*modification of natural radionuclide distribution by some human activities in Canada. This paper discussed the statistical elements of the early surveys and these data have been used in implementing the practical program. Technical solutions to the problem of excess radon and radon daughters in buildings have been found which depend only upon available North American building materials. Three main techniques for remedial action are being applied, a) removal of the source material: This has mainly been applied in Port Hope which is uniquely a contamination problem. b) ventilation of the sub soil. For those cases where the soil is relatively porous, it has Been possible to divest any radon

109 bearing 9*« to the atmosphere before it enters the lived-in volume. Some experimental results are provided. c) Sealing of the foundation. Standard building materials applied in a novel fashion have proven to be effective in rendering old foundations radon proof. From this, building techniques have evolved tha,. can be applied to new construction. Examples of each are illustrated and some representative costs are presented. There is a brief discussion of energy conservation techniques and the effects on air quality through the reduction in the ventilation rate in housing. From this there is a suggestion that air quality assurance that may be required for the future will also provide a universal and long term mechanism for the reduction of radon concentrations in buildings.

- 110 - V-B 2

SADON AND ITS DAUGHTERS IN ENERGY-EFFICIENT BUILDINGS

A.V. Nero,. M.L. Boegel, CD. Hollowell J.G. Ingersoll, and W.W. Nazaroff

Energy Efficient Buildings Program Energy and Environment Division Lawrence Berkeley Laboratory Berkeley, CA 94720 March 31, 1980

Radon daughters in buildings contribute a significant, perhaps dominant, part of the natural radiation dose to which the general public is exposed. This dose may Increase as a result of energy-conservation measures that decrease mechanical ventilation or infiltration rates in buildings. As part of our efforts to assess the potential impact of such measures, we are carrying out a program to characterize indoor radon sources and concentrations and to evaluate the effectiveness of control measures. This paper will describe our measurement activities in three areas: 1) radon emanation from building materials; 2) radon and radon-daughter concentrations in energy-efficient residences; and 3) the effectiveness, as a control measure, of mechanical ventilation with air-to-air heat exchangers. In measuring radon emanation, we initially examined concrete, and now have extended our work to an examination of other materials, including soil taken from sites where indoor concentration measurements are being performed, and rock samples from solar thermal-storage beds. Emana- tion rates are measured in two ways: 1) by collecting radon from a radon- emanating material and transferring it to a scintillation cell where it is counted, and 2) by measuring gamma emission rates from samples in sealed and unsealed containers. For concrete samples taken from five U.S. metropolitan areas, the emanation rates per unit mass ranged from 0.4 to 2 pCi/kg/hr. This corresponds to a surface emanation rate, for 0.1 m thick concrete,*of about 0.03 pCi/m^/sec. We have measured radon and radon-daughter concentrations in energy- efficient houses, including demonstration or research structures, occupied houses designed to have low infiltration rates, and solar houses employing rock-bed thermal storage. In a series of mid-1979 radon measurements performed in such houses, grab samples of air were analyzed in a scintillation cell and infiltration rates were measured using a tracer-gas technique. The resulting data are displayed in the Figure. We continued to measure many of these houses during the following winter, obtaining similar results. Our field measurements to determine the effectiveness of air-to-air heat exchangers in maintaining indoor air quality have included tests in a Maryland research house in which the radon concentration was found to exceed 20 nCi/m3. Intensive measurements of radon and radon-daughter concentrations were performed over a two-week period during which the air-

- -HI - exchange rate was varied using a mechanical ventilation system with a heat exchanger. The radon concentration was found to vary approximately in inverse relation to the air-exchange rate, but the potential alpha energy concentration and the individual daughter concentrations exhibited more complex dynamic behavior, particularly following changes in the air- exchange rate or in the operation of the air circulation system. Heat- exchanger testing is proceeding in occupied houses in California, Min- nesota, New Mexico, New York, and other areas of the U.S. RADON CONCENTRATION vs. VENTILATION IN ENERGY EFFICIENT HOUSES

0.1 0.01 Air change rate (hr ) XBL 801-38

- 113 - i/-8 2

RADON LEVELS IN HOMES IN THE NORTHEASTERN UNITED STATES Robert L. Fleischer, Antonio Mogro-Campero, and Larry G. Turner, General Electric Research and Development Center, Schenectady, NY 12301 USA Exposure to high levels of Rn-222 and its radioactive daughters in mines leads to lung cancer (1,2). The logic is widely accepted that the primary effect is not due to Rn-222 itself, since inhaled Rn-222 is mostly expelled, but is from the decay of alpha-active progeny of the radon, Po-218 and Po-214, which are attached to aerosols that can be lodged in the lungs when inhaled. Although the effects of radon have been documented only for large exposures, linear extrapolation of the results given in ref. 2 to the lower levels normally experienced in the environment implies that a few thousand people in the United States die each year from lung cancer that is induced by levels that are typically (3) of the order of 0.8 pCi/£ in homes. If the linear extrapolation of the dose-effect relation is correct, then even modest increases in radon, such as result from many measures that reduce heat loss from dwellings, could have a profound effect on human life. In "energy efficient" homes for example the median value of 14 such houses was found to be about 3 pCi/S, (4). An appropriate measurement for providing relevant radon levels must be capable of integrating over substantial periods of time to determine the average exposure of occupants of the dwelling. To such measurements dielectric track detectors are well suited, since as now used (5) they are rugged, thermally insensitive, inexpensive, passive, and have the needed sensitivity. In a set of measurements to test the environmental levels present in homes in Schenectady and the ease of measuring typical environmental levels, six first-floor locations in different homes gave an average level of 0.61 p_Ci/£ and five basement locations in three homes and an apartment gave 1.45 (-0.12) pCi/X/. The ratio of the first floor to cellar concentrations of radon agrees with earlier findings on 21 homes in New York and New Jersey (3). For radon at equlibrium the levels w ; measured correspond to 0.008 and 0.015 working levels, and the exposures (which were times between 60 to 100 days) correspond to doses of 0.016 (-0.010) to 0.18(-0.02) WLM. If, as is likely, radon was not at equilibrium, the doses were even lower. In addition, one poorly sealed basement with a dirt floor contained 6 pCiA and one well-sealed solar home contained 12.4 pCi/8.. In the latter case an impure sand used as a heat-exchange medium was capable of emitting radon at a rate of about 0.5 atoms/cm2-sec, and is the probable source of the elevated radon level. The radon level reached in the living space of the solar home is such that a person who occupies that space for 20 years, 12 hours a day will have approximately a 32 WLM exposure. The mine data (2) predicts a 1% chance of fatal lung cancer from such an exposure. Further studies of solar heated, well sealed homes are in progress and will be reported. 1/-B 4

Indoor Measurements of Natural Radioactivity in the Federal Republic of Germany

GERT KELLER Institut für Biophysik Universitat des Saarlandes 6650 Homburg (Saar) Federal Republic of Germany

Within an investigation (supported by the Federal Minister of the Interior) the exposure to external radiation from naturally radioactive substances in dwellings and in open air was determined in the Federal Republic of Germany. Approximately 30000 measurements of gamma-ray dose rates indoors and 25000 outdoors were carried out. The mean value in dwellings is 8.0 |iR/h (the maximum value was found to be more than 30 iiR/h) and in open air 6.0 |iR/h. The living in houses increases the average annual gonad dose by 10 mrem. The results of the measurements revealed a dependence on the time of construction/ type of construction and on the region within Germany. The differences are related to the building material employed. More than 500 samples of building materials have been analyzed by means of gamma-ray spectroscopy to determine their specific content of Potas- sium-40, Radium-226 and Thorium-232. The results have been compared to those of the measurements of gamma-ray dose rates. The large number of data obtained permitted to quanti- tatively evaluate the exposure of the population to external radiation by naturally radioactive substances taking into account the influence of building materials. The noble gases Radon-222 aud Thoron-220 and their daughters released by.the building materials have to taken into account if the exposure in dwellings of the population is to be evaluated. They are the main contributors to the dose of the population due to inhalation.Radon and Thoron daughters were measured by analyzing the activities deposited on a membrane filter applying a-spectrometry. The concentration of Radon and Thoron were determined using a method of electrostatic deposition and a-spectrometry. The lower limit of detection of this method is approximately 10~4 W.L.. More- over, parameters such as building material, paint-work, ventilation of rooms, meteorological data and concentration in outside air have been taken into account. Indoors the concentration of Radon daughters in the air was higher by a factor of 3, óf Thoroh daughters by a factor of 8 when

- 115 - compared to the open air. The measured average concentrations of activity in the air of Po-218, Pb-214 and Bi-214 were used to calculate the annual doses of the population due to inhalation by Radon-daughters applying the lung model of ICRP-30. The contribution of the air indoors to the total exposure of the lung is approximately 10 times higher than that of open air. A decisive factor for the annual exposure of the lung is the ventilation ra^e which is strongly influenced by energy saving methodes. ;If an average ventilation rate of 0.5 h~1 is assumed an average exposure of one to two rem a~1 has expected for the critical region of the basal cells of the bronchial epithelium. Therefore the respiration region receives the maximum natural exposure and is simultaneously exposed most strongly to other environmental toxic agents. Concepts of building construc- tions should include in future aspects of avoiding an increased exposure of the total population. References Der Bunctesminister des Innern. Die Strahlenexposition von auBen in der Bundesrepublik Deutschland durch natürliche radioaktive Stoffe im Freien und in Wohnungen unfcer Beriick- sichtigung des Einflusses von Baustoffen. Forschungsbericht 1978

KELLER, G., H. MUTH und F. OBSRHAUSEN. Radioactivity in Building Materials. Internationale Atoinenergiebehörde (IAEA) pvien, Health Physics Research Abstracts (HPRA) 5 (1974) KELLER, G., H. SCHMIER und W. SEELENTAG jr.. Externe Exposi- tion durch terrestrische Strahlung in Gebauden. Die natür- liche Strahlenexposition des Menschen. Grundlagen zur Beur- teiiung des Strahlenrisikos- Stuttgart, Thieine Verlag (1970) 7Q - 79

KELLER, G.f H. MÜTH, B. GLÖBEL und E. OBERHAUSEN. Rn- exhalation from building materials. Internationale Atoia- energiebehörde (IAEA) Wien, Health Physics Research Abstracts (HPRA) 5 (1978)

'7 - l/~B 5

INDOOR PHANTOM DOSE CALCULATIONS AND MEASUREMENTS

I. Fehér, A. Andrasi, L. Koblinger, P.P. Szabó and P. Zombori Central Research Institute for Physics P.O.Box 49, H-1525 Budapest, Hungary. The applicability of deep dose-equivalent index for characterising indoor natural external radiation environment is studied. Calculational models, checked by experiments, are used in the investigations. An adjoint Monte Carlo code was developed that calculates .the air kerma and the dose spectrum at any point in the room, or the deep dose-equivalent index, the dose distribution and the dose spectra inside a 30 cm diameter sphere which is filled with tissue equivalent material /with unit density/ and placed to any position into the room. The activity concentrations of the K—40 isotope, the U/Ra/-series and the Th-series are input data of the code. Doses absorbed in the whole body, in the testicles, ovaries, red /active/ marrow, or in the lungs of the inhomogeneous antropomorphic ORNL phantom were also computed for the same room geometries and radioactive source concentrations in the walls. The organ doses were compared with the deep dose indices and with the doses refering to different depths of the spherical phantom. To check the calculations the air kermas, the deep dose-equivalent indices and dose distributions were measured in several rooms. CaS04:Tm thermoluminescent dosimeters were used for this purpose. The average concentrations of the natural gamma-emitting sources were determined by gamma spectrometry, by evaluation of the most characteristic peaks. The calculated and measured deep dose-equivalent indices and dose distributions are in good agreement. The use of the deep dose equivalent indices in indoor external radiation fields lead to conservative estimation of the effective dose equivalent. The shielding factors /i.e. the ratios of the organ and the air kermas/ are also given and from these factors points in the spherical phantom can be selected so, that the doses at their sites are equivalent to the doses in the proper organs of the antropomorphic phantom. V-B 5

Buildings with enhanced radioactivity in Sweden

Gun Astri Swedjemark

National Institute of Radiation Protection Box 60204 S-104 01 Stockholm, Sweden

Enhanced radon/radon daughter concentrations indoors have been found in some houses in Sweden especially in combination with low air exchange rates. The radon sources have been found to be some types of building materials, some types of filling materials, some types of ground under or around the houses and any combination of these sources. The radon source may also be radon-rich tap water. The same types of building materials also give an enhanced gamma radiation level.

Most of the building and filling materials giving rise to enhanced radioactivity in Sweden today are based on alum shale. The most common of these materials is alum-shale based aerated concrete which contain about 1 300 Bq kg"1 (35 pCi g"1) of radium-226 as a weighted average for all the producers. Wastes from the handling of alum shale at pro- ducing burned lime or alum have been- used as filling materials around houses, in floor structures and as ballast materials in ordinary concrete. The waste material contains between 1 000 Bq kg"1 and 3 900 Bq kg-1 (27 - 100 pCi g"1).

The concentrations of radon and radon daughters, if-radiation levels and air exchange rates for various types of houses have been investigated. Continuous registrations of the radon concentrations have been carried out in some of the houses.

The radon concentration indoors in houses almost entirely built of alum- shale based aerated concrete were between 200 and 1 200 Bq m~3 (5 - 32 pCi 1 ) and the air exchange rates between 0.2 and 0.6 changes per hour as averages for the houses. The absorbed dose rates in air from y-radiation indoors were between 350 and 690 nGy h"1 (35 - 69 urad h"1) as'averages of measurements in the middle of the rooms.

In houses built of normal materials on wastes from alum shale mining and with air exchange rates between 0.09 and 0.28 changes per hour the average radon concentrations in the houses were found to be between 400 and 1 500 Bq m"-* (11 - 40 pCi I"1).

In houses built of concrete with alum-shale vaste as ballast material, with the same material as filler around the foundations and with approximately 0.5 air exchanges per hour the radon concentrations found were between 500 and 800 Bq m~3 (13 - 22 pCi I"1).

In all the houses both lower and higher concentrations of radon have been found in individual rooms and at single measurements.

For some types of houses various technical solutions for reducing the radon/radon daughter concentrations have been tested.

- 119 - RADIOACTIVITY OF BUILDING MATERIALS.ABSORBED DOSES

L.Garzön.P.Fontenla y A.Suérez Energy Nuclear Departement.Oviedo Untverstty.Spain.

INTRODUCTION

Due to the fact that the majority of materials used tn building derive from natural materials existing in the cortex of the earth, they contain, like these,^another so_ me of lesser importance) in variable proportions, the K-40 nuclide and those constituting the natural radioactive se_ ries.As a consequence, the structures built by man with th£ se materials give rise, on one hand, to a gamma emission, which would superimpose that of the earth's cortex and,on the other,'a release of Radon (Rn~222) and Toron (Rn-220)ga_ ses .For this reason., in the interior of buildings the do_ ses absorbed, external as well as internal, would be supe_ rtor to those of the so called natural background radiation The determination of the concentrations of the mentioned ra dtoact^ve nuclides in building materials holds importance tn that it permits estimation of the absorbed doses. In this study only the gamma doses are considered.Other studies in this area have been realised by LUNDH(1.974},HULTQUIST(1956) SOLON(I.960],LINDEKEN(1.973). EXPERIMENTAL

The K-40,Ra-226 and Th-232 concentrations have been determined in 100 samples of building material, the majori_ ty of which came from the Asturian region. An, Intertechnique gamma spectrometer SA-41 of 400 channels was used, with a tube provided with an INa(Tl) detector of 3" x 3" convenien_ tly situated in a lead shield. The Specimen carrier is a ma_ rinelli type;its capacity allows for 1000 g of material.The analysis was carried out by comparison with adequate stan_ dards. The peaks choosen, in Kev,are those indicated as fo Hows: K-40(1461);Ra-226(60?) and Th-232(2615)

RESULTS Table I gives in pCi/g the mean values of the radioa£ tive nuclides for the materials indicated. In relation to the concentrations of the mentioned nuclides in igneous rocks, Cl»3 pCi/g) granites, wall-tiles and cements exceed these values for the Ra-226.For the Th-232 are the granite, wail-ttles and bricks, and for the K-40 only the granites. External doses.A series of gamma measures were carried out in the interior of buildings by means of a gammameter GMT 3T adjusted to a Rustrand recorder .The said measurements we_ re compared with the values obtained by applying a model in which each parament is considered like a disc of equal thicK ness to the parament. The results obtained are shown in Ta ble II REFERENCES

HULTQUISTiB.;KUNGL.SUENSKA VETENSKAPSA-KADENUENS LINDERKEN.C.L.,JONES,D.E. y McMILLEN.R.E.;HEALTH PHYSICS,24_ 81-86(1.973) LUNDH.A.;BRITISH JOURNAL OF NDT,16,174-78(1.974 SOLON,L.R.;LOWDER,W.M.,SHAMBON,A y BLATZ.M. ;SCIENCE 131 903 (1.960). TABU I

Ra-226,TF)-232 AND K-40 CONCENTRATIONS IN BUILDING MATERIALS

lATERIALS Ra-226 Th-Z3Z K-40 >ANDS 0,38±0,14 0,47-0,09 7,21±3,81

CIMENTS 2,04±0,28 0,82^0,32 6,45^0,57 GYPSUMS 0,08^0,00 0,25i0,00 6,06±0,18

GRAVELS 0,62±0,34 ND 1,28-1,19 PLASTERS ND 0,21^0,00 13,21^0,35

JRICKS 0,92t0,ll 2,68^0,41 18,00^3,78

GLASSES 0,36±0,00 0,26±0,00 1,84-0,02 WALL-TILES 1,90-1,20 2,36io,60 21,89-8,54 GRANITES 2,09^0,67 2,81^1,63 . 28,02^5,38 MARBLES 0,36^0,00 0,33^0,00 1,02^0,08 IRONS ND ND ND

NOODS NM NM ND TILES 1,52^0,06 1,70^0-, 01 23*. 20-0,95

^. -1 '7 ". TABLA II

INDOOR GAMMA DOSES

BILDINS TYPE 'mrem/year SITE

IRON STRUCTURE 41*14 OVIEDO BRICK AND CONCRETE 62*16 OVIEDO BRICK AND CONCRETE 56tl6 QIJON WOOD STRUCTURE AVILES STONE AND CONCRETE 116+37 TRUBIA I. -b « INDOOR CONCENTRATIONS OF Rn-222 AND Rn-220 DESCENDENTS.AB SORBED DOSES

Ü.Garzón.P.Fontenia y A.Suérez Energy Nuclear Departement.Oviedo Untversfty.Spain. INTRODUCTION The materials used in building, contain, in variable proportions, the radioactive nuclides of the U y Th series Of these, the Rn-222 and Rn-220, which belong respectively to each of the mentioned series, are gases, and therefore, after a process of emigration through the paraments, fina_ lly reach the surface of these, to incorporate in the inte_ rior atmosphere in the which they continue their disinter gration, originating the so called solid descendents,which" attach to the particles which form the atmospheric aerosol Incorporation of this particles to the diverse branches of the respiratory tract gives rise to a dose, which is gene_ rally superior to due the exterior air. Although measures have been taken of Rn and descen_ dents in enclosures such as tunnels, caves and others(DU GGAN,1.968;ISRAELS0N,1.972;LUCAS,1.973;SCHR0EDER 1.965;WTL KENING-,1.976),little attention has been paid to the inte_ rfors of building. The object of this study is the estima_ tion of doses absorbed by the respiratory tract due to des_ cenftents of Rn and Tn.

EXPERIMENTAL Concentrations of descendents of Rn-222 and Rn-220 are determined by measuring total alfa activity of the ra_ dioactive aerosols deposited on a filter using a SZn( Ag) detector of 210 mm diameter. In relation to other methods, this stands out for its hingh efficiency and low background noise,F0NTAN(1.964) On calculating the concentrations from the measure ments of activity from the filter, the influence of ventT_ lation and recycling were taken into account.Measures were taken in rooms with diferent types of ventilation. RESULTS. . The values of the doses have been obtained from the corresponding concentrations using the expression: E.R.V. l,6.10"6.103.60.10 D- 100.P ,E(mev] being the total alfa energy liberated in the series tof desintergration corresponding to 1 litre of air; R the fraction of aerosols retained in the lungs; V(l/m) the vo_ lume of air inhaled for each unit of time and P the mass, in grams, of the lungs. The numeric factors are factors of conversion, having taken equal to 10 the factor of relative biological efficiency for the alfa particles. The values obtained for doses depend on ventilation. Thus, for a badly ventilate*! room and a stay of 8 hours daj_ Ty, the total dose due to descendants of Rn-222 and Rn-220. is around 900 mrem/year.In normal ventilated rooms the dose varies according to the type of room, between 50 and 200 mrem/year.

REFERENCES

DUGGAN>H.J.,HOWELL,D.M.,SOILLEUX,J.C, NATURE, 219,1149(1968) F0NTAN,J.;7HESE DE DOCTORAT ES-SCIENCES PHYSIQUES N°218, TOULOUSE(1.964). ISRAELSON,S.,KNUDSEN,E.y UNGTHUM.E.;REPORTS No.30,MARST OB SERVATORY.UPPSALA,SWEDEN (1.972). LUCAS,H.F. y GABRYSH.A.F.; ARGONNE NAT.LAB.RADIOLOGICAL PHYS.DIVISION ANNUAL REP.ANL-7220(1.966) SCHROE.DER,G.L.,KRANER,H.W. y EVANS,R.D. ;0 .GEOPHYS.RES. ,70 NUM 2.471(1.965). • WILKENING.H.K. y WATKIND.D.E.;HEALTH PHYSICS,31,139(1.976) 'J-B 9

RADIOACTIVITY OF BUILDING MATERIALS IN POLAND3*/

K.Mamont-CieJla, B.Gwiazdowski, M.Biernacka, A.Zak, Central Laboratory for Radiological Protection Warsaw - POLAND Abstract

Naturally occurring radionuclides in building materials are a source of external and internal radiation exposure to inhabitants. Uncontrolled introducing of new raw materials such as byproducts of power industry /fly ash and slags/ to the production of building materials to be used for construction of dwellings may cause significant increase of this exposure. Among several hundred samples of raw and final building materials the samples of fly ash and slag have the highest content of natural radioactivity. It ranges up to 980 Bq/kg /26,5 pCi/g/ of K-40, 252 Bq/kg /6,8 pCi/g/ of Ra-226 and 107 Bq/kg /2,9 pCi/g/ of Th-232. The dose rate inside a dwelling constructed of a material containing such level of radioactivity is estimated to be 1,99 mGy per year what corresponds to the gonadal exposure of 1,38 mSv per year /taking into account the indoor occupancy factor equal to 0,8/. This estimation was made by using Koblin- ger'S CodeCl] for the calculation of radiation in dwellings. These results indicate the necessity of controlling and limiting the use of some raw materials. We have established limits [2] for the concentrations of naturally occurring radionuclides within each type of building material approved for use in home construction. They havexa form of two conditions:

1/ f% - 0,01 CK + 0,1 CRa + 0,16 CTh ^ 1 def. 2/ f2 - CRfl < 5 pCi/g where CK, CR , CTb - concentration of K-40, Ra-226 and Th-232 respectively, in pCi/g. d*f. -3 _3 -3 1/ t± • 0,27 X 10 °CK + 2,7 X 10 ° CRa + 4,3 xlO ° CTh^l def. 2/ f g •-' CRa < 185 Bq/kg where CK, CR , C^. - concentration of K-40, Ra-226,and Th-232_resgectively, in Bq/kg. £7?his work was partly supported by the IAEA research contract No 2415/RB The firse condition la educed from the assumption that the maxtlmum dlf faranca batwaan gonadal doaa in a living home and in tha ao called "klark" home ia laas than 80 area par year /Tha "klark" home neana a building constructed of Material of activity aqual to tha world average radioactivity of soil fel : K-40 - 10 pCi/g, Ra-226 - 0,7 pCi/g and Th-232 .0.7 pCi/g/, Tha second condition'is intended to limit the exposure to the lung and bronchial epithelium form alpha radiation coaing from radon daughters. It was derived from the assumption that in extreme cases the radon concentration in air coming from building materials shall not exceed the limits accepted by Polish regulations for a group of population that stays in the vicinity of nuclear institution. This permits the maximum additional bronchial exposure from radon daughters equal to 56 mSv per year. In order to implement tha limits into building material trade a special device with three channel analyser based on NaO/Tl/ spectrometry to be installed in bigger mo/iufactories was designed and constructed in Central Laboratory for Radiological Protection. CLRP along with the Institute of Building Technology are have elaborated a control system which is supposed to prevent from utili- sing building materials exceeding adopted limits of the specific activity of naturally occurring radionuclides for living home construction.

References fll Koblinger,L. /1975/: Calculations on the gamma levels ,in rooms due to radioactive sources in the walls. Paper 62, 3 rd European Congress of the Interna- tional Radiological Protection Association, Amster- dam. May 1975. £2] Mamont-Cieéla.K. et al. ."Provisional recommendations of tha permissible level of the specific radioactivty naturally occurring in building materials /In Polish/. Interior Report of CLRP No 24/77/Z-II /1977/. UNSCEAR /1977/. Sources and effects of ionizing radiation. New York, United Nations.

- 127 - THE ASSESSMENT OF INDOOR EXPOSURE FROM GAMMA EMITTERS AND RADON-222 IN POLAND X B.Gwiazdowski, K.Mamont-Ciesla, M.Biernacka

Central Laboratory for Radiological Protection Warszawa - POLAND Abstract

Among all natural sources of ionizing radiation it is building materials which give a significant contribution to the total dose, and one which can be influenced by man. In addition to gamma exposures, construction materials may contribute to radon daughters exposures. The magnitude of the latter exposures is strictly connected with the radium content in building materials and depends on ventilation conditions. In Poland studies of the natural background and the measurements radiation doses in the buildings as well as radon and its daughters in air concentration have been carried out for some time. The work is coordinated by the Central Laboratory for Radiological Protection, Warsaw, and contributed to by the Nuclear Research Institute at Swierk, the Institute for Nuclear Physics, Cracow, and Departments of Physics of the Medical Academies in Lublin and Biaiystok. For the measurement of the indoor exposure high pressure ionization chambers, made of steel bottle of 5 litre volume filled with argon at pressure of about 35 at. have been used in most cases. The signal was measured by a Vakutronik VA3-type electrometer. The chambers were calibrated and the sensitivity checked periodically by using already reported procedures £l, 2], Several series of measurements were performed using the thermoluminescence detectors and gamma spectrometry in situ £3]. The measurements of radon-222 were done iising ordinary scintillation chambers and the daughters concentration in air by the Markov method [.41. All the measurements were performed during the worst ventilation conditions, i.e. after closing the room for minimum 8 hours before air sampling. During the period 1966 - 1979 the Central Laboratory for Radiological Protection, Warsaw, has performed several series of indoor exposure measurements in the living houses of different type and technology of the building x/ 'This work was partly supported by the IAEA research contract No 2415/RB in the following regions of Poland: Warsaw, tod*. Katowice, Lublin, Biaiystok and Kraków. The Measurements of the indoor exposure rate were done at several points in every apartment, and the mean value was taken as a representative result. Depending on the dominating material of the dwelling, we have divided all houses into three groups: 1-wooden, 2- masonry, made of different kind of brick, and 3- having concrete and the so called "prefabricates" as the dominating material. The summary of results obtained for 672 dwellings shows that the mean exposure rate for wooden houses results in 8.5,uR/h /including the cosmic radiation component/ and ranges from 5.5 - 12.9,uR/h. For masonry buildings it is 9.4/UR/h within the range from 6.6,uR/h to 24.2yuR/h, and'for concrete 9.8^!?/*! within the rranga e of 5.3/uR/R/h to 17.8/uR/h/h . Thhe calculatelld d gonadadl doses for these three types of houses are - 0.47 mGy/a, 052 raGy/a and 0.54 mGy/a respectively, taking, into account the occupancy factor equal 0.8. The summary of the results of radon measurements for 201 dwellings in Poland shows that the mean concentration of radon inside the wooden houses results in 0.16 pCi/1 and ranges from 0.06 - 1.6 pCi/1. For masonry - 0.24 pCi/1, within the range of 0.03 - 5.34 pCi/1 and for concrete - 0.30 pCi/1 in theo range 0.02 - 2.14 pCi/1. The values obtained for the mean alpha potential energy are also in the same order, resulting in for wood- 0.8 mWL, masonry - 1.2 mWL and for concrete as dominating material - 1.5 mWL. Corresponding dose equivalents, calculated for the occupancy factor equal 0.8 and for bad ventilation conditions, have also the greatest value for concrete - 3.8 mSv/a to the lung and 12.8 mSv/a to bronchial epithelium, when for brick or masonry buildings they result in 3.0 mSv/a to the lung and 10.2 mSv/a to the bronchial epithelium, being for wood 2.0 mSv/a and 6.8 mSv/a respectively. Table 1 presents the results of the assessment of annual doses from indoor exposure in Poland calculated on the basis of the measurements performed in the years 1966 - 1979. When using the official statistical data for the year 1969 - 20% of the population was living in wooden houses, 68% - in masonry and only 12% in concrete and prefabricates. For this population distribution one obtains the following components of gonadal dose per capita: wood - 0.07 mGy/a, masonry - 0.27 mGy/a and concrete 0.05 mGy/a» This results in the total dose equal 0.39 mGy/a per capita, for occupancy factor equal 0.8. Similarly the contribution to the per capita dose equivalent to the lung is from wood - 0.40 mSv/a, masonry - 2.04 mSv/a and from concrete 0.46 tnSv/a, resulting in

- 129 - total dose equivalent 2.9 mSv/a. For bronchial epithelium the corresponding values are: wood - 1,36 mSv/a, masonry - 6.94 mSv/a and from concrete - 1.54 mSv/a. The total dose equivalent per capita being equal 9.84 mSv/a. The results obtained indicate the possibility of increasing indoor exposure considering the actual trend development of building materials used for living houses. This is especially true for Poland where the building materials technology is increasingly based on power industry and chemical wastes, such as fly-ash, boiler and blastfurnace slags etc. These materials may have considerable concentrations of Ra-226, Th-232 and K-40. The measurements of activity of building materials performed in Poland indicate for the necessity of controlling and limiting the use of some raw materials. We introduce the following protection standards for building marerials in Poland: - the radioactivity of the building material shall fulfil two conditions, def. + + 16 *S 1 ; 1/ fl 0.01 CK 0.1 CRa °- h def• f 5 v 2 cRa ^ pCi/g

C and C, concentr where K . cRa Ra-226 and Th-232 respectively, in pCi/g. The discussion of the limits, and results of building material radioactivity assessment have been published elsewhere [53. Literature

O.Oagielak, B.Gwiazdowski, O.Pensko, A.2ak, "Some problems of calibration for environmental gamma exposure dose measurements". Environmental Surveillance Around Nuclear Installations, SM-180/2, IAEA. Warsaw 1973. B.Gwiazdowski, "Environmental Gamma Background Radiation Measurements in Poland", Dahrestagung des Verbandes fur Strahlenschutz, Helgoland 1974. T.Niewiadomski, et al., "Comparative study of different methods used in assessment of population exposure to external radiation field", IF3 Report, Kraków 1979. [4] 0.Hermann, U.Ullasnn, Chr.Feddersen, F.Frleaert, 3.Schwedt, "Methods'for aeasureaent of radon and radon daugher products in underground and free atonosphere air, SM-22<5, 22 lAcA, Stockhola 1978. [5] K.Maaont-Ciesla. B.Gwiazdowski, M.Biernacka, A.2ak, "nödioactivicy of building aaterials in Poland", this symposiua abstract»

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- 13': - RADON DAUGHTER EQUILIBRIUM IN DWELLINGS

Andreas Wicke Institut für Strahlenhygiene, Bundesgesundheitsamt, Ingolstadter Landstr. 1, D-8051 Neuherberg Justin Porstendörfer, K~ H. Becker, Centrales Isotopenlabor der Universitat Göttingen, Burckhardtstr. 2, D-3400 Göttingeïn

Introduction Energy saving and home insulation is expected to increase radon (Rn-222) and radon daughter concentration in dwellings and may thus raise the r isk of lung cancer. The assessment of a representative annual exposure is difficult because there is a great variability of airborne radioactivity depending on nusteorological conditions (1),- ventilation (2) and radon-source location. In addition, information about radon daughter equilibrium and fraction of atoms net attached to aerosols is needed for dose calculations. It is evident that no radioactive equilibrium between the radon daughter products is reached in dwellings. However, experimental results cannot be explained by air-exchange processes alone (3). Other factors have to be taken into account , such as aerosol concentration, -size distribution a.xi-5. deposition processes. The objective of this paper is, to d iscuss these influences on a theoretical basis and c:ompar;e them with experimental results.

Theoretical model Assuming a constant emanation from the buiding material, radon reaches a stec idy-state concentration indoors (c1) according to (4): c1 = (e^ -4- v ca)/(A + v) , -3 —1 where e is the radon emanation in terms of Bq m h , v the ventilation rate (h~1), A the decay constant of Rn-222 (h~1) and ca is the concentration of radon outdoors. The concentration of an j-th daughter product (c.) can be.- expressed by t'ne concentration of the previous (j-V) one. A distinction has to be made between the activity of the free ato'ms (c(f)) and that attached to aerosols (c!f>) (4):

a f f (v c < >+ X. cji«* r^ J^c^/Cv • Aj+ g< > + X, cj(a) = (v jj., j ^ j y

These expressions are considering the attachment rate X (in h~1) of atoms to aerosols, the probability of their recoil Jr), the deposition rate of atoms (qff>) and aero sols (q*a'j on floor and wall surfaces in terms of h"1. A rather homogeneous activity distribution and no pre- filtering of the incoming air is assumed. According to UNSCEAR (5), radon daughters may be com- prised of the so-called equilibrium equivalent concentration (ce) which relates to the potential alpha energy concentration. Thus, the equilibrium between radon (c) and its daughters (ce) can be described by the equilibrium factor F (5): „ Ce

To estimate possible ranges of F, information of ev, v, q(f), q(a), x and r is needed. Corresponding values were derived from basic studies referred to in the extended paper.

Results At ventilation rates between 0.1 and 1 h usually found in German homes, the equilibrium factor is rather low (0.3 - 0.6) and decreases with increasing emanation. If aerosol concentration is raised (e.g. by smokers), the equilibrium factor is also increasing (see fig.!) because the number of daughter-atoms, which plate out, is reduced. However, even at very high aerosol concentrations radioactive equilibrium is not reached, because a certain fraction of the attached atoms is always lost by turbulent deposition on walls and furniture. A At average aerosol concentrations (1 - 2 x 10 particles per cm-*) the attachment rate of the daughter atoms to aerosols is in the range of 30 - 70 h~1. With a ventilation rate of 0.1 h~1 and a mean radon emanation of 7.3 Bq m"3h"' (0.2 pCi l~1h~') (2), the equilibrium factor is expected to be between 0.3 and 0.5. This result is in good agreement with direct measurements (2).

133 AEROSOL CONCENTRATION, 103part. cm"3 10 100 1.0 i T I I I I I I l l i

0.9 enhanced aerosol concentration 0.8

0.7

average « 0.6 aerosol concentration s H Bi CD H D theoretical 0.3 curve(*)

0.2

0.1

0.0 50 100 500 ATTACHMENT RATE X, h-1

Fig.: Equilibrium factor for radon daughters related to different aerosol concentrations and attachment rates, respectively - experimental results and theoretical calculations. The following parameters are assumed: (*) radon emanation : 7.3 Bq m~3h"1 removal rate: -1 unattached fraction: 30 h-1 attached fraction: 0.2 h-1 ventilation rate : 0.1 h

•34 Conclusion Although the theoretical model is restricted to steady- state conditions, it is a useful guidance to study the influences of different factors on the activity balance of radon daughters in dwellings. In agreement with experimental data the calculations have shown that a rough estimate of the radon daughter exposure in dwellings can also be achieved by radon measurements alone, applying an equilibrium factor of 0.3 to 0.5. Nevertheless studies on this subject should be continued to improve the understanding of the behaviour of radon and radon daughters indoors. Acknowledgements This study was financially supported by the Bundesminister des Innern of the Federal Republic of Germany under contract St. Sch. 603. References (1) STEINHfiUSLER. F. (1975): Long-term measurements of 222Rn,220Rn, 214Pb and 2T^Pb concentrations in the air of private and public buildings and their dependence on meteorological parameters. Health Phys. 19, 705 - 713. (2) WICKE, A. (1979): Untersuchungen zur Frage der natür- lichen RadioaktivitSt der Luft in Wohn- und AufsnthaltsrMumen. Dissertation Universitat Giefien. (3) JONASSEN, N. (1980): Measurements of radon and radon daughters. Paper presented at the Radon Specialist Meeting in Rome, March 3-7, 1980. (4) PORSTENDÖRFER, J., A. WICKE, A. SCHRAUB (1978): The influence of exhalation, ventilation and deposition processes upon the concentration of radon (222Rn), thoron (220Rn) and their decay products in room air. Health Phys. 34, 465 - 473. (5) UNSCEAR (1977), United Nations Scientific Committee on the Effect of Atomic Radiation: Sources and Effects on Ionizing Radiation. 1977 Report to the General Assembly, New York.

- 135 - IN AIR AND VA3SR V.V.Zuzminov, l.O.Nevinsky, A.A.Pomansky Institute for üiuclear Research of the USSR Academy of Sciences

Ehe results of permanent measurements of 22Hn in air and water in vicinity of the Baksan Neutrino Observa- tory are presented. An estimation of the 222Rn 3^4 its daughter product counts to the total background counting rate is made. 2?p An extraction Rn from water was made by helium flux with small portion of Xe as gas-carrier. Then extracted 222fin g^a Xe after purification was put into small low-background proportional counter. Height of the

- 136 - Measurement of radon and radon daughters in various Scandinavian environments. C. Samuelsson, RBR. Persson, E. Holm. Department of Radiation Physics, Lund University, S-221 85 Lund, Sweden.

Results from a research program devoted mainly to measurement of radon and radon daughters in indoor and outdoor climates are presented. In dwellings the results of filter grab sample methods and passive track film exposures are in good agreement. The great variability in radon concentration in houses' with meteorological conditions (fig. 1) limits the utility of single air sample measurements.

pulses

Fig. 1. The radon concentration in a dwelling as measured with a continous monitoring ZnS-cell system. The pulsrate is corrected for the memory effect of the cell.

- 137 - In filter methods invovling total alpha measurements during two or more consecutive time intervals, one most pay careful attention to the energy dependence of the detector and plate out effects in the sampling head, in order to evaluate correctly the individual contribution from RaA, RaB and RaC-C'. For low-level monitoring of radon, air samples are concentrated on cooled charcoal traps and transferred to ZnS-cells. High volume air samples are used for assessment of short lived daughter products in outdoor air. The filters are also analyzed for 210po and 210pD activity by chemical separation technique. Measurements of radon and radon daughters will be undertaken in connection with the investigation of a prospected uranium mining site in the vicinity of Rörvattnet, Sweden (64° N and 13,8° E). This area is low populated and the release of radon will be of no health problem but it is important to study the release of radon and radon daughters in connection to uranium mining for further mining activities. Radon from the oceans is two or three orders of magnitude less than over land surface areas. Early experiments have showed that pulses of radon (radonic storms) are frequently encountered over ocean areas and are associated with high continental dust concentrations. Observation of this phenomenon and correlation with weather charts will be studied in connection with the Swedish Ymer-80 expedition to the polar basin during the summer 1980 (see map below).

- 138 60*W FRANZ JOSEFS LAND

- 139 - .'1-0 3

ATMOSPHERIC FLUX OF 210Pb IN THE NORTHWESTERN UNITED STATES Ahmad Nevissi Laboratory of Radiation Ecology Colleqe of Fisheries University of Washington Seattle» Washington 98195 The integrated monthly total deposition of 210pb has been measured at Seattle, Washington (47° 36' N, 122° 22' W) over a period of six years. The monthly 210pb fiux shows a marked seasonal variation, with peaks in the late fall or winter and trough's in the summer. The data consistently shows that the seasonal variation is correlated to the monthly rainfall, Figure 1. The annual 210pD fiux •,-„ Seattle ranges from 0.17 to 0.75 dpm/cm2/yr with an average value of 0.45 dpm/cm2/yr. The contribution of dry fallout to the annual flux is about 14%, Figure 2. The more than four fold variation observed in the annual flux of zl0Pb during the course of this study may suggest a periodic pattern of 210pD deposition possibly correlated with the solar activity. The main source of <-luPb to Seattle is the Eurasian Con- tinent. Radon and its decay product 210pD are supplied to the troposphere from this source and are then transported by the prevailing winds eastward over the North Pacific. It seems that the transfer of 210p|j -fn the troposphere over the North Pacific is not continuous throughout the year. The 210pb injected into the stratosphere in spring and summer does not leave until the following fall or winter. Earlier work at another North Pacific station, Amchitka Island (51° 28' N, 179<> 06' E), also confirms the above conclusion, Nevissi and Schell (1978). Seasonal vari- 137 ation of 210pD values in Amchitka were similar to the Cs values in air filter samples collected at ground level. Since the source of 13?cs is from nuclear detonations that have injected debris into the upper troposphere/lower stratosphere, it can be concluded that a considerable fraction of the 210Pb which is deposited in the North Pacific comes from the same storage reservoir as 13/Cs, namely the upper troposphere/lower stratosphere.

A. Nevissi and W. R. Schell. 1978. The use of 210Pb and 210Po as tracers of atmospheric processes. IN: The Natural Radiation Environment III (in press). 0.21 _i

I'll I • I ' I ' I r I 0 3.0 6.0 9.0 12.0 15.0 16.0 17.0 18.0

Rainfall cm/mo

Figure I. Monthly luPb total deposition against the monthly deposition at Seattle, Washington (September 1973 - July 1979). 180-

160.

140.

120-

'100.

80-

60.

40.

20. I is Uli 1' ' I o J D J J J J 1975 1976 1977 0 J 1979 73 1974 1978 DATE

0 J 73 1974 DATE

figure 2. Monthly dn'osition of 210Pob (A) and its variation with the rainfall In Seattle (B). The dashed lines represent the intrapolated values. NOISE ANALYSIS OF RADON FLUX

M. Arabzadezan, E. E. Carroll, Jr., and J..A. Wethington, Jr. Department of Nuclear Engineering University of Florida Gainesville, Florida, 33611, U.S.A.

Radon emerging from the Earth's surface is subject to diurnal variation, weather variables, seasonal fluctuations, etc. Our measurements of radon flux (pCi/m2sec) showed wide variations at different locations on the same piece of land and even wide variations at the same sampling point. These latter variations are studied in this paper.

The charcoal canister technique was used to measure radon flux at four locations in Florida. Three canisters were deployed for approximately three days at each location, and the three results were averaged to give an observation for that week. Results are summarized in Table I. The large standard deviation of these signals suggested that radon flux might be a mixture of random and periodic functions as is the case for many geophysical phenomena.

The raw data were first treated with a low-pass digital filter (cut- off frequency set at three-fourths of the Nyquist frequency) to remove any aliasing effects. The data were then autocorrelated to yield 4>11 (x), defined as 1 fT $11 CO - lim -^ l(t + T) - radon flux at week (t + T) T - lag time, weeks.

The net effect of this analysis was to compress the white noise to the vicinity of T - 0. The autocorrelation function was then multiplied by a Hanning lag-window to reduce the uncertainty band. This resulting function was Fourier transformed to yield amplitudes and frequencies of periodic components present in the original signal.

The data summarized in Table I were analyzed by this method, and the periods shown emerged. In each case, the peak-to-valley ratio was more than twice the uncertainty at the 90% confidence level.

This work shows that radon emanation from the ground, at least in some locations, contains periodic components superimposed on an apparently TABLE I Radon Flux Data

Observation Percent Period, Mean Flux, Standard Observed Perioda Location Weeks pCi/m2, sec Deviation (weeks)

Polk County: A 84 4.58 38 24,8,17

Polk County: B 84 0.32 43 10,7,34,14

Gainesville: A 96 0.41 72 48,22,14

Orlando: A 80 1.67 29 32,16,12 a. Listed in order of decreasing amplitude for each location. random signal. Establishment of mean radon flux at a particular geographical location therefore requires a long-time sampling program. Replicate samples must be obtained over time intervals at least equal to the longest period in these oscillations; otherwise, a true average value, useful in human exposure calculations and in geophysical exploration, is not obtained. The necessity for space replica- tion has been established in another publication.^

References

1. A. C. George, "Scintillation Flasks for the Determination of Low Level Concentrations of Radon," in Operational Health Physics, Proc. Ninth Midyear Top'l Symp. Health Physics Soc, pp. 112-115, Denver, CO (Feb. 9-12, 1976). 2. M. A. Haghi.N. K. Savani, P. V. Rao, and J. Wethington, Jr., "Statistical Analysis of Radon Flux Measurements," Third Int. Conf. National Radiation Environment (in press), Houston, TX "(Apr. 1978).

145 - PP2 KSHAIAÏIOH OF Sa mCM SOU, - SOME ASEBCTS CF VABIATIOTS M. Baghavayya, A.H. Khan, H. fadmnabhan aad G.K. Srirastava Health ïhyaics Division Bhabha Atomic Besearch Centre Health Physics Unit, Jaduguda Singhbhum, Bihar.

Inhalatioc of radon is on» of tbe prime sources of population exposure to natural radiation background. This e ome a about due to 222Ba and 2203^1 reaching the atmosphere by exhalation from soil, aad emanation from surface waters which almost always contain the gas in the dissolved stats. The background radon level in the air also gets enhanced in certain areas where uranium mining and processing of uranium and thorium ores are undertaken. The paper deals with the exhalation of radon from soil and uranium mill tailings piles. This process ia a complex phenomenon. The exhalation rate my depend on such variables as radium content, moisture cozrtent and porosity of soil, variation of atmospheric pressure, humidity, temperature, wind speed and so on» In an attempt to eliminate variations introduced by geographical location we estimated the exhalation rate at a fixed location. For this purpose, a long perforated cylinder was buried in the ground with one end threaded and exposed» A radon scintillation chamber could be coupled to this exposed end at will and counts could be taken in situ. Measurements were carried out almost daily over a one year period. Bzhalation rate has shown a wide variation, from almost zero to plus 900 pGi/m2. ain. Measurements are still being continued. It was aeen t&at exhalation rate fall drastically aoon after a heavy shower 7?h«n the ground wa3 soaking wet. Smanaticn was found to increase a3 the ground began to dry and fall again when the ground waB bone dry. Radon exhalation rates w«r

~~Hawrynski M., Domanski T.~~

Institute of Occupational Medicine, 90-950 Lódz,P.O.Eox19S Teresy 8 Str., POLAND Abstract The theory of the formation of water envelope, so called cluster (CLR) , arround free ion of radon daughter products is presented in this paper. The theory of interaction between free ion and water-phase in ambient air has been based on two assumptions: a/ water which fronts CLR is the ordered pool of electric dipols; b/ surfaces tention of CLR has been calculated using values of empirical data. The theory is of classical character, however, the quantum -mechanical manner has been applied for the calculation of cross-section for the collision between the cluster and air molecule. The relation between relative humidity (H) , temperature (T) , and radius (r) of CLR is derived as follows:

#b - surface tention of water, k - Boltzmann constant, m - mass of water molecule, ,u - dipol moment of water molecule, f\ - mass density of 'water, e - charge of electron, go - dielectric constant of vacuum, L - Langevine's function, R - Debye's correlation factor. The diffusion coefficient of CLR can be calculated according to formula:

mj - mass of air molecule and CLR respectively to index i, a.. - radius /analogically/, n - sum of number of air molecules and CLR per cubic meter. The rule for calculation of ion recombination coefficient has been derived as follows: x'performed under USEPA - Washington D.C. contract No 05-536-5.

~~- 147 - HawryiSski M. et al. 2nd page~~

~~z 128 r jïtkT -exp Treor kT )~~

~~The results of calculations of CLR's parameters are show in the table 1.~~

~~Table 1. The parameters of CLR calculated for the different values of relative humidity~~

~~Relative Radius Number Diffusion Recombi- humidity of CLR of H20 coefficient nation of the air particles of CLR coeffi- 2 cient of creating [cm /s] ion M of CLR~~

1.0 6.0 30 0.0241 2.18'10"5 5.5 7.0 48 0.0187 3.17.10"6 16.7 8.0 72 0.0150 7.27*10~7 35.1 9.0 102 0.0123 2.27.10~7 58.4 10.0 140 0.0102 8.76^10~8 82.3 11.0 187 0.0086 3.97<10"8 103.5 12.0 242 0.0074 2.03-10-8

The range of the fluctuations of CLR diameter at constant humidity of air has been calculated. It that was found those are less than 2 percent of the diameter. The main conclusions of derived theory are as follows: - the diameter of CLR depends on relative humidity of ambient air and fluctuates in a very small range; - the time of CLR formation depends on relative humidity however it is rather short since does not exceed 10-3 s, - the radon-daughter products practically must pass though the stage of CLR prior to their further interactions with aerosols in ambient air. VI-A 7

~~Los Alamos Scientific Laboratory Life Sciences Division, Environmental Sciences Group~~

~~Quantifying the Radon Impacts of Passive Solar Heating~~

~~John C. Rodgers~~

There is a growing concern that the requirements of building design for energy conservation in general, and passive solar heating in particular, are such that a significant elevation of radon and radon daughters in"the indoor environment Kill occur.1'2 Since a potentially large volume of soil can contribute radon to a dwelling by diffusion, and by convection under conditions of changing atmospheric pressure, even soils containing relatively low concentrations of radium can create transient elevated radon levels in homes. If, in addition, the design of the structure for passive solar applications requires incorporation of large amounts of masonry, rock, or the like, for thermal mass, additional radon flux into the indoor air can result. Other passive solar design features which might be of significance include rock bed heat storage bins excavated into the subsoil, which would provide for increased contact between soil gases and indoor air, excavated pit solar greenhouse collectors, and earth- berm or underground passive solar designs. The plants and planter beds in solar greenhouse collectors may also be of significance although they may be only incidental to the heating design. These passive solar design aspects are being studied in a Solar Energy Research Institute sponsored project at the Los Alamos Scientific Laboratory. Particular emphasis is being given to quantify the radon flux from various potential contributors to the radon gas concentration in indoor air. In order to quantify the overall potential health impacts of this pollutant, measurements will have to be made for a full year (one complete heating-cooling cycle).

1. A.C. George and A.J. Breslin, "The Distribution of Ambient Radon and Radon Daughters in Residential Buildings in the New Jersey and New York Area" Symposium on the Natural Radiation Environment III, Houston, TX, April 23-28, 1978. 2. CD. Hollowell et. al., "Radon-222 in Energy Efficient Buildings" presented at the American Nuclear Society Meeting, San Francisco, CA, November 11-16, 1979.

~~- 149 - OS TOS SIZE DISTBIHJTiar OF BADOU DMJGHUB AJSB0S0I8 IH THB ATBCSIHBBE~~

~~P.7. Joshi aal O.I. Kelkar Air Monitoring Section Bhabba Atomic Besearch Centre Bombsy-400 085.~~

Over tbe laat decade or so, with more sophisticated instrumentation and better understanding about tbe dynamics of aerosols, new concepts are emerging about the si» distribution of aerosols in the atmosphere. The biological effects of aerosols are closely connected to their size distribution, which in turn, determines the extent to which they are deposited in different parts of the respiratory system. As per the terminology which is in use at present one is required to estimate the fractions known as "attached" and "unattached" in determining the effect of radon daughters. However the terms "attached" and "unattached" are not very clear. Instead if one assumes a continuous size distribution right from their generation to their ultimate loss due to the radioaetiTe nature (which is much shorter than the average residence time of atmospheric aerosols, in general) a simpler model for their inhalation characteristics can be worked out. Hecent studies on gas to particle conversion phenomenon applicable to non-radioactive gaseous species like SO. suggests that the radon daughter should also behave in a similar fashion by incorporating themselves into some of the cluster aerosols formed* The else distribution measurements coadueted on radon daughter in Trombay supports this hypothesis. lbs diffusion method is used for this studies. Ibis method is suitable for radon daughters, since it is associated with the smaller partioles in the atmosphere. Tbe technique is very simple. Aerosol is passed through a single channel and the fraction of radioactivity deposited in the channel or penetrating through, is determined by estimating the radioactivity of tbs residual particles. Aluminium tubes were used for tbe experiments. Penetration of radon daughters through the aluminium tubes was determined by collecting them on a millipore filter paper and comparing their activity with a parallel sample collected without a preceding tube. The estimated penetration fraction gives the diffusion coefficient of tbe partioles under known experimental conditions. Diffusion coefficient can be used to determine the particle site. The method discussed above can estimate tbe sise of tbe monodispersed particles. But sine» atmospheric particles are polydlspersed, it is necessary to relate tbe effective diffusion coefficient to the sise distribution of tbs particles. logarithmic •ormal distribution would be a reasonable choice for the atmospberio aerosols. The paper presents the estimation of the distribution parameters by visual comparison between the calculated psnetntlon curves for Log Voraal distributions with tbs experimental curves under varying experimental conditions. Using this technique some studies on tbs size distribution of radon daughter aerosols in Trombay were carried out. following conclusions were drawn from these studies. 1. The effective diffusion coefficient of the size distribution of radon daughters in Troabay range from 10~2 cm?/sec. to 3.6 x 10~2 oa/sec. These values of the diffusion coefficient correspond to particle with radii of 23 A0 and 12 A° respecting and these are likely to be the modal values of the size distribution. Estimated median values work out to be 50 A" and 20 A0 respectively. 2. The freshly formed radon daughters In the processing plant gave smaller size 20 A° (g.m.d.) as compared to 50 Ac in open atmosphere away from the processing plant. This confirms that in the atmosphere where aerosols are highly dispersed the size of the radon daughters is a function of their age rather than their attacbment to preformed atmospheric nuclei. 3. Badon daughter products in the atmosphere have a size distribution similar to the total aerosols. They are found in the lower Aitksn nuclei size range similar to other products of gae-to-particle conversion reactions. . It is suggested that the size distribution of the radon daughters should be treated as continuous as that of other aerosols and that the effective diffusion coefficient in combination with g.s.d. is a more meaningful parameter to characterize the Log Koraal size distribution of radon daughter aerosols than the usage of the terms "attached" and "unattached". 1/1--A 9 i PROBABILISTIC TREATMENT OF THE BUILD-UP AND THE DECAY OF Rn-DAUGHTER PRODUCTS 1 2 Peter 6. Groër and Ram Uppuluri

A mathematically exact treatment of the stochastic build-up and decay of Rn222-daughter products in the atmosphere and on a filter paper is presented. We show that the usual deterministic equations used to describe this stochastic phenomenon coincide with the mean value equations of the underlying stochastic process. The rigorous stochastic treatment enables us also to calculate the exact variances and distributions for the number of Rn-daughter atoms in the air and on a filter. The effects of a stochastic source term during build-up are discussed, and the implications of the stochastic description for the determination of low, natural airborne concentrations are illustrated.

~~1 Institute of Energy Analysis, Oak Ridge Associated Universities, P. 0. Box 117, Oak Ridge, Tennessee 37830, U.S.A.~~

~~2 Mathematics and Statistics Research Department, Union Carbide Corporation, P. 0. Box 7, Oak Ridge, Tennessee 37830, U.S.A. • VI -B 'i~~

~~HOW TO ASSESS TERRESTIAL DOSE RATES WITHOUT RADIOHETRIC MEASUREMENTS~~

~~M. Jasiriska, T. Niewladomski, J. Schwabenthan Institute of Nuclear Physics, Krakow, Poland~~

ABSTRACT Present measurement methods of dO3e rate from natural sources of gamma radiation are time-consuming and require precision instruments and skilled personnel. The results depend on the local physico-chemical properties of the soil, which may vary from site to site and therefore extrapolation to larger areas is unreliable. The concentration of some elements contained in the upper layer of the soil (Ad73, Sa75), can be correlated to the mechanical composition of the soil parameter i.e. of the contents by weight of particles smaller than 0.02 mm in diameter. These particles, owing to their large unfolded surface, exhibit high sorption properties. Our hypothesis is that the concentration of the naturnaturaal radionuclides, such as 2238u, 232

~~Correlation factors "]~~

~~23% «*» Cose rate~~

~~0.81 0.96 0.87 0.93~~

~~•" A- f. /• . yt.57*0.08fx 30~~

~~to P'0.93~~

~~(SI CC: a to I2~~

~~tO 20 30 W 50 60 70 80 % offracHons <0p2 mm~~

Fig.1 Dose rates 1m above the ground"va weight percentage of adsorbing fractions in soil. In the diagrams the equations with tht parameters of linear depedence as well as correlation factors "r" and error of estimation •Sy" ar« given. /1yuraa h"1 = 2.78 pOy s"1 / i'l-3 2

SEASONAL VARIATION OP SHORT-LIVED RADON DAUGHTER ACTIVITY OF RAIN WATER Susumu Minato Government Industrial Research Institute, Nagoya Hirate-machi, Kita-ku, Nagoya, Japan The study of the washout of radon daughters from the atmosphere to the ground surface is important from a standpoint of earth science as well as from a viewpoint of environmental radiation monitoring in the vicinity of nuclear facilities. Since December 1976, the natural gamma radiation flux density has been observed in our laboratory. I have reported in a previous paper (1) that the mean specific activity of rain water, , is related to the additional flux density due to the washout, $, and rainfall amount, P, as follows

~~4- AB~~

Here, b and c are constants, and X_ and Xr the decay constants of RaB(Pb-2l4) and RaC(Bi=21i»), which are short-lived decay products of Rn(Rn-222). In this paper, I would like to mention the seasonal variations obtained from observations made over the period of 3 years using above equation in connection with changes in the concentration of atmospheric radon daughters obtained using filter pack method. Figure 1 shows the monthly mean specific radioactivity of RaB and RaC in rain water together with the monthly mean atmospheric radon daughter concentration. The strong relation is seen between them. Both the specific activity of rain- water and atmospheric radon daughter concentration in summer are less than those in winter. Although the trend of variations coin- .cides fairly well each other, it may be necessary to ascertain whether this coincidence results by chance or there is a some valid mechanism relating them. Reference 1. Minato, S. (1978) Some observations of the variations In natural gamma radiation due to rainfall. The Natural Radiation Environment III, in press. 300 'Activity of rain water c*% ,Atmospheric j *^ radon f- 200 daughters /I* O UI O o a 100 5

~~JFMAMJJASONDJFMAMJJASONDJFMAMJJASOND 1977 1978 1979~~

~~Fig. 1 Monthly mean specific radioactivity of rain water and atmospheric radon daughter concentration. VI-8 1~~

~~RADIUM-226 IN PLANTS AND SUBSTRATES AT INACTIVE URANIUM MILL SITES IN THE SOUTHWESTERN UNITED STATES~~

~~M. Lynn Marple Los Alamos Scientific Laboratory Environmental Science Group P.O. Box 1663, MS 495 Los Alamos, New Mexico 87545 USA~~

The uptake and trsnslocation of contaminants from uranium mill tailings piles and other similar wastes (such as uranium mine spoils and phosphate mine tailings) could be an important transport mechanism of these contaminants into the environment. Radium-226 is of particular concern due to its long half-life and its ability to be accumulated in bone. This work is the study of the content of radium-226 in plants growing on inactive uranium mill tailings sites in the Four Comers Region of the southwestern United States and in plants pown under greenhouse conditions with minimal surficial contamination. Field plant samples and associated substrates were analyzed from two carbonate tailings sites in the Grants Mineral Belt of New Mexico. Radium activities in-air-cleaned samples ranged from 5 to 368 pCi/g (dry weight) depending on species and location; activities in plants growing on local soils averaged 1.0 pCi/g. The tailings and local soils contain 140-1400 pCVg and 2.1 pCi/g. respectively. An evaluation of cleaning methods on selected samples showed that from 1? to 79% of the radium activity measured in air-cleaned samples was due to sur- ' ficial contamination, which varied with species and location. A survey of 18 inactive uranium mill sites in the Four Comers Region was performed. Radium activity in plant tissues from nine species ranged from 2 to 210 pCi/g on bare tailings and from 0.3 to 30 pCi g on covered tailings. The radium content in most of the soil overburdens on the covered tailings piles was 10 to 17 pCi/g. An experiment was performed to measure radium-226 uptake by two species grown on tailings covered with • shallow (5 cm) soil layer. A grass, Sporobolus airoides (alkali sacaton i and a shrub. Atripltx canescent (four-wing saltbush), were studied. The tailings were a mixture of sands and slimes from a carbonate pile. The tailings treatments were plants grown in a soil cover over tailing»; the controls were plants grown only in soil. Three soil types, dune sand. clay loam, and loam, were used. The radium activity of the plant tissue from the tailings treatment compared to that of the appropriate control was 1 to 19 times greater for the grass and 4 to 27 timt» greater for the shrub. 2 2 23%, ^ Jht *°Z ALQHG THE MAIN 3KM ADIT OF THE 2AESA& SEÜTSISQ OBSBSTAZQET S.L.Xovalchuk, A.A.Pomansky, A.A.SmolnikoT, A.H.femmoev Institute for JNuclear Research of the USSR Academy of Sciences

The main aim of this work is to select optimal underground points for placing the low-background laboratories. The results of measurements of 2*ÖU, 232Th and *PK concentrations along the 3 km mainly shale underground way show that those concentrations in average do not differ from usual dark concentrations (3*4xlO~5 gU/g, l*2adO~5 gXh/g). However there are areas in the adit where U, ïh and K concentrations are significantly less than the averages. In these areas the shale is enriched with quartz. The results of measurements are presented in table 1. TABLE 1

~~- 159 - METHODOLOGICAL ASPECTS OF THE ASSESSMENT~~

~~OF POPULATION EXPOSURE TO IONIZING RADIATION~~

~~G. UZZAN, R.MAXIMILIEN Commissariat a 1'Energie Atomique Département de Protection Association EURATOM/C.E.A. BP N° 6, 92 26o FONTENAY-AUX-ROSES,France~~

~~SUMMARY~~