IAEA Laboratory Activities

TECHNICAL REPORTS SERIES No. 77 IAEA Laboratory Activities

FOURTH REPORT

INTERNATIONAL ATOMIC ENERGY AGENCY,VIENNA, 1967

IAEA LABORATORY ACTIVITIES

Fourth Report The following States are Members of the International Atomic Energy Agency:

AFGHANISTAN GERMANY, FEDERAL NIGERIA ALBANIA REPUBLIC OF NORWAY ALGERIA GHANA PAKISTAN ARGENTINA GREECE PANAMA AUSTRALIA GUATEMALA PARAGUAY AUSTRIA HAITI PERU BELGIUM HOLY SEE PHILIPPINES BOLIVIA HONDURAS POLAND BRAZIL HUNGARY PORTUGAL BULGARIA ICELAND ROMANIA BURMA INDIA SAUDI ARABIA BYELORUSSIAN SOVIET INDONESIA SENEGAL SOCIALIST REPUBLIC IRAN SIERRA LEONE CAMBODIA IRAQ SINGAPORE CAMEROON ISRAEL SOUTH AFRICA CANADA ITALY SPAIN CEYLON IVORY COAST SUDAN CHILE JAMAICA SWEDEN CHINA JAPAN SWITZERLAND COLOMBIA JORDAN SYRIAN ARAB REPUBLIC CONGO, DEMOCRATIC KENYA THAILAND REPUBLIC OF KOREA, REPUBLIC OF TUNISIA COSTA RICA KUWAIT TURKEY CUBA LEBANON UKRAINIAN SOVIET SOCIALIST CYPRUS LIBERIA REPUBLIC CZECHOSLOVAK SOCIALIST LIBYA UNION OF SOVIET SOCIALIST REPUBLIC LUXEMBOURG REPUBLICS DENMARK MADAGASCAR UNITED ARAB REPUBLIC DOMINICAN REPUBLIC MALI UNITED KINGDOM OF GREAT ECUADOR MEXICO BRITAIN AND NORTHERN IRELAND EL SALVADOR MONACO UNITED STATES OF AMERICA ETHIOPIA MOROCCO URUGUAY FINLAND NETHERLANDS VENEZUELA FRANCE NEW ZEALAND VIET-NAM GABON NICARAGUA YUGOSLAVIA

The Agency's Statute was approved on 26 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of the Agency are situated in Vienna. Its principal objective is "to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world".

Permission to reproduce or translate the information contained in this publication may be obtained by writing to the International Atomic Energy Agency, Kârntner Ring 11, A-1010 Vienna I, Austria.

Printed by the IAEA in Austria September 1967 TECHNICAL REPORTS SERIES No.77

IAEA LABORATORY ACTIVITIES

The IAEA Laboratories at Vienna and Seibersdorf

The International Laboratory of Marine Radioactivity at Monaco

The International Centre for Theoretical Physics, Trieste

The Middle Eastern Regional Radioisotope Centre for the Arab Countries, Cairo

Fourth Report

INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 1967 IAEÀ LABORATORY ACTIVITIES - Fourth Report (Technical Reports Series, No. 77)

ABSTRACT. This fourth report describes development and work during the year 1966. It includes activities of the IAEA Laboratories at Vienna and Seibersdorf, the International Laboratory of Marine Radioactivity at Monaco, the International Centre for Theoretical Physics at Trieste, and the Middle Eastern Regional Radio- isotope Centre for the Arab Countries at Cairo. Contents: The IAEA Laboratories at Vienna and Seibersdorf: Introduction; Standardization of measurement and of analytical methods related to nuclear energy applications; Analytical services to Member States; Chemical and physico-chemical investigation relevant to the Agency's programme; Nuclear energy applied to agriculture; Nuclear energy in medicine; Nuclear energy in hydrology; Nuclear electronics service and development; Administrative matters, staff members and publications. - The International Laboratory of Marine Radioactivity at Monaco: Introduction; Research; Administrative matters, staff members and publications. - The International Centre for Theóretical Physics, Trieste: Introduction; Assistance to developing countries; Administrative matters, staff members and publications; Appendix: Statistical digest. - The Middle Eastern Regional Radioisotope Centre for the Arab Countries, Cairo: Introduction; The scientific programme of the Centre; Accepted papers and scientific reports on results of work done in the Centre; Laboratory, research and training facilities; Scientific visits to the participating States and the IAEA; Finance. Entirely in English.

(148 pp., 16X24 cm, paper-bound, 23 figures) Price: US $1.00; 7/2 stg (1967)

IAEA LABORATORY ACTIVITIES, FOURTH REPORT IAEA, VIENNA, 1967 STl/DOC/lO/77 FOREWORD

This fourth "IAEA Laboratory Activities" report describes the work during the year 1966. It includes activities of the Agency's Laboratories at Vienna and Seibersdorf, the International Laboratory of Marine Radio- activity at Monaco, the International Centre for Theoretical Physics at Trieste, and the Middle Eastern Regional Radioisotope Centre for the Arab Countries at Cairo. The Agency expresses its gratitude to the Governments of Austria, Monaco, Italy and the United Arab Republic for their generous continued assistance.

CONTENTS

THE IAEA LABORATORIES AT VIENNA AND SEIBERSDORF

I. INTRODUCTION 3

II. STANDARDIZATION OF MEASUREMENT AND OF ANALYTICAL METHODS RELATED TO NUCLEAR ENERGY APPLICATIONS 5 1. Calibration of radionuclides 5 1.1. Development of counting methods 1.2. Techniques associated with standardization 1. 3. Determination of constants relevant to standardization 1.4. Neutron fluence measurements 1. 5. Tritium assay for the Division of Safeguards 1.6. Distribution of radioactive standards 2. Radiation dosimetry 8 2.1. Absorbed dose measurements by calorimetry 2.2. Ferrous sulphate (Fricke) dosimeters 2.3. Lithium fluoride dosimeters 2.4. Carbohydrate dosimeters 3. Reference materials 15 3.1. Supply of analysed uranium ores 3.2. Analysed sample of uranium oxide containing trace impurities 4. Analytical quality control 17 4.1. Need for quality control of analytical procedures 4.2. Results of intercomparison runs 4.3. Average reliability of environmental analysis 5. Trace element analysis 19

III. ANALYTICAL SERVICES TO MEMBER STATES 27 1. Tunisia . 27 2. Venezuela 27 3. The Sudan 27

IV. CHEMICAL AND PHYSICO-CHEMICAL INVESTIGATION RELEVANT TO THE AGENCY'S PROGRAMME 28 1. Analytical chemistry in the Safeguards Programme 28 2. Analytical chemistry in the Life Sciences Programme 28 2.1. Determination of iodine in blood 3. Studies on decomposition under radiation sterilization 30 4. Purity of commercial radiochemical preparations 31

V. NUCLEAR ENERGY APPLIED TO AGRICULTURE 33 1. Soil fertility, irrigation and crop production 33 1.1. Co-ordinated rice project 1.2. Co-ordinated maize project 1. 3. Co-ordinated research programme on tree crop fertilization 1.4. Co-ordinated programme of plant nutrient supply and movement in soils

2. Determination of nitrogen-15 concentration in nitrogen 46 3. Entomology 48 3.1. Mediterranean fruit fly 3.2. Olive fly 3.3. Tsetse fly 4. Genetics and plant breeding 50 4.1. Research on mutation induction in agricultural crop plants 4.2. Mutagen service treatments 5. Food irradiation 57 5.1. Effect of gamma irradiation on several horticultural products 5.2. Temperature dependence of PME activity 5.3. Effect of gamma irradiation on PME 5.4. Determination of cellulase activity

VI. NUCLEAR ENERGY IN MEDICINE 60 1. Development of techniques and instrumentation 60 1.1. Medical activation analysis 1.2. Radioisotope scanning 1.3. Whole-body counting 1.4. Statistics of radiation measurement 2. Activities in support of laboratories in Member States 69 2.1. Protein turnover studies 2.2. Support of whole-body counting activities in Member States 3. Study of toxicity of Thorotrast in Vienna cases 71

VII. NUCLEAR ENERGY IN HYDROLOGY 72 1. Tritium 72 1.1. Enrichment by electrolysis 1.2. Enrichment by gas chromatography 1.3. Gas counting 1.4. Liquid scintillation counting 1.5. Sampling of air humidity for tritium measurement 2. Carbon-14 . 74 2.1. Extraction of carbonates from water 2.2. Proportional counter

VIII. NUCLEAR ELECTRONICS SERVICE AND DEVELOPMENT 76 1. Random coincidence simulator 76 1.1. Principle of operation 1. 2. Coincidence resolution and dead-time measurement 1.3. Counting error 1.4. Measurement of differential linearity of time-to-pulse-height converters 2. Detailed discussion of the instrument 79

IX. ADMINISTRATIVE MATTERS, STAFF MEMBERS AND PUBLICATIONS г 81 1. Training 81 2. Laboratory equipment donated by Governments of Member States 81 3. Finance 82 4. Professional staff of the laboratory 84 5. Publications by staff members . 92 6. Papers presented at scientific meetings by staff members 93

THE INTERNATIONAL LABORATORY OF MARINE RADIOACTIVITY

AT MONACO

I. INTRODUCTION . 97

II. RESEARCH 98 1. Work at sea 98 1.1. Diffusion processes in the sea 1.2. Organic aggregates 1.3. Vertical transport of radionuclides by biota 2. Work in the laboratory 100 2.1. Chemistry of sea-water 2.2. Chemistry of sediments 2.3. Radiobiology of marine organisms

III. ADMINISTRATIVE MATTERS, STAFF MEMBERS AND PUBLICATIONS 109 1. Site, facilities and equipment 109 2. Finance 109 3. Professional staff of the laboratory 110 4. Publications by staff members Ill THE INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS, TRIESTE

I. INTRODUCTION 115

II. ASSISTANCE TO DEVELOPING COUNTRIES 116 1. Associate memberships 116 2. Fellowships and other positions 116 3. The Advanced School of Physics 116 4. Dissemination of scientific information 117

III. ADMINISTRATIVE MATTERS, STAFF MEMBERS AND PUBLICATIONS 118 1. Finance 118 2. Scientific staff 118 2.1. Elementary particle physics group 2.2. Plasma physics group 3. Scientific documents 120 3.1. Publications and preprints issued in 1966 3.2. Library and scientific information

APPENDIX: STATISTICAL DIGEST 126

THE MIDDLE EASTERN REGIONAL RADIOISOTOPE CENTRE FOR THE ARAB COUNTIRES, CAIRO

I. INTRODUCTION 131

II. THE SCIENTIFIC PROGRAMME OF THE CENTRE 132 1. Training 132 2. Research 133 2.1. Hydrology 2.2. Agriculture 2.3. Entomology 2.4. Medicine

III. PUBLICATIONS, ACCEPTED PAPERS AND SCIENTIFIC REPORTS ON RESULTS OF WORK DONE IN THE CENTRE 143

IV. LABORATORY, RESEARCH AND TRAINING FACILITIES 145 V. SCIENTIFIC VISITS TO THE PARTICIPATING STATES AND THE IAEA 146 1. The Sudan 146 2. Iraq 146 3. Kuwait ! 146 4. Libya 146 5. The Agency 147

VI. FINANCE 148

THE IAEA LABORATORIES AT VIENNA AND SEIBERSDORF

I. INTRODUCTION

As an introduction to this fourth report we quote the ad hoc Committee1 appointed in November 1966 by the Director General of the IAEA, to review the accomplishments of the Agency's Laboratories and advise him on their future activities. "In many areas of nuclear energy there are scientific and technical problems of common interest to many nations which cannot always be adequately solved by national organizations alone, or even by groups of organizations. In such areas the Laboratories of the IAEA can play an important and con- structive role. Examples of areas pertinent to the Seibersdorf and Head- quarters Laboratories are: the preparation and distribution of internationally acceptable standards for particular measurements needed in atomic energy research and development; the establishment of standard methods for quality control of nuclear materials; the establishment of standard, or guiding procedures for particular problems in nuclear energy; the world-wide collection of samples of particular interest, their analysis, and the drawing of unbiased conclusions from the results; the co-ordination of programmes aimed at testing the adequacy of various measurement techniques in common use. Such activities are appropriately carried out by an international organization, which can make substantial contributions to peaceful nuclear energy programmes both in developing countries and in advanced countries. Throughout its review the Committee found that the projects being carried out in the Laboratories characteristically reflect this broad aim and include one or more of the above-mentioned aspects. The Committee feels that significant contributions have been made, and judges the present activities of the Laboratories to be very satisfactory. " It should also be mentioned that the Directors General of the Food and Agriculture Organization of the United Nations (FAO) and of the IAEA have appointed a Consultant Group2 to review and advise on the programme and activities of the Joint FAO/IAEA Division of Atomic Energy in Agriculture. From the report submitted in September 1966 by this Consultant Group we quote the following overall evaluation of the work carried out by the Agri- culture Section of the IAEA Laboratory: "The Laboratory activities are an integral part of the programme of the Joint Division .... The function of the Agriculture Section is to provide supporting analytical, irradiation and other ancillary services for the field programmes, and to carry out such limited pieces of development as may speed up the progress of any programme .... We were greatly impressed

1 Composed of R.W. Dodson, Brookhaven National Laboratory, Upton, N.Y., USA-, T. Nakai, Japan Atomic Energy Research Institute, Tokai Mura, Japan; P.J. Nowacki, Institute of Nuclear Research, Warsaw, Poland; M. Theys, Commissariat 5 l'énergie atomique belge et Conseil national de politique scientifique; Brussels.Belgium, 2 Composed of Sir John D. Cockroft; С. Dakshinamurti, Director of Agricultural Physics, Indian Agri- cultural Research Institute, New Delhi, India; A. Gustafson, Department of Forest Genetics, Royal College of Forestry, Stockholm, Sweden; A.W. Lindquist, Bridgeport, Kansas, USA.

3 4 VIENNA AND SEIBERSDORF 4 that ... a very great deal of high quality work was being carried out by an enthusiastic staff." As far as the organization scheme of the Laboratory is concerned, it has been described in the First IAEA Laboratory Activities Report (Tech- nical Reports Series No. 25, IAEA, Vienna (1964)). No changes have been made in this respect. II. STANDARDIZATION OF MEASUREMENT AND OF ANALYTICAL METHODS RELATED TO NUCLEAR ENERGY APPLICATIONS

The development of standards and standardized methods of measurement and analysis for the manifold peaceful uses of nuclear energy is one of the important statutory tasks of the IAEA. Such activities have been from the very beginning specifically recommended: "The Agency should take .. . measures for the preparation and distribution of standardised radioactive samples and formulate recommendations for the calibration of equipment and for appropriate methods of measurement. "3 A review of the achieve- ments made in this field during 1966 is given below.

1. CALIBRATION OF RADIONUCLIDES

1.1. Development of counting methods

Improved counting methods were developed for the calibration of the following radionuclides :

Iron-55. Two different tracer methods were used:

(a) Mixed sources of 55Fe and 54 Mn are prepared. The counting efficiency for the 54Mn К X-rays in а 2тг proportional counter is determined by X-y coincidences and then used for extrapolating the 55Fe X-ray counting rate to zero self-absorption; (b) Mixed 55 Fe and 59lTe electroplated sources, with practically no self- absorption of the X-rays, are counted in a 2ir geometry. The yield of the electroplating process, which cannot be measured directly, is determined by counting the y-rays emitted by 59Fe. The contribution of this nuclide to the counting rate in the X- ray counter is small and can be subtracted.

Thorium-230. The preparation of high-efficiency a-sources, accurately weighed, from solutions with a high carrier content and high acidity is difficult. In the present method the aliquot is deposited on a filter paper, which, after drying, is soaked with a scintillator solution, a-efficiencies up to 99% were obtained, as determined by a-y-coincidence counting.

Sodium-22. It is usually assumed that straightforward 4гг @-y-coincidence counting gives directly the absolute activity of the source, Я the discrimina- tion in the Y-channel is set just below the photopeak of the 1240-keV 7-ray.

3 Report of the Preparatory Commission of the International Atomic Energy Agency, New York 1957, par. 39, p. 12.

5 6 VIENNA AND SEIBERSDORF 6

However, even under this condition the summing of a Compton energy loss of the 1240-keV 7-ray, and an annihilation photopeak contributes appreciably to the 7-counting rate. Consequently, the simple coincidence method may be wrong by several percent. Since this is a second-order effect, it can be eliminated by stepwise increasing the distance between the 4гг Э-counter and the Nal crystal, and extrapolating to a 7-efficiency of zero.

Cobalt-57. A relatively simple method for the calibration of this radionuclide was developed. If in both the 4гг 0- and the 7-channel the efficiencies for the two branches (EC - 136 keV and EC - 122 keV - 14 keV) (EC = Electron-Conversion) are about equal, the quotient of the singles product and the coincidence counting rates becomes the disintegration rate. The method is somewhat similar to that recommended by Meyer et al.4 for y-y - and /З-7-coincidence calibrations.

Yttrium-88. When calibrating this radionuclide by X-7-coincidence counting, using a thin and a large Nal crystal, y-y-coincidences can cause an appreciable error. This effect can be eliminated by some additional measurements and a simple mathematical treatment of the results.

Calibration of soft )3-ray emitters by liquid scintillation counting. It was shown theoretically that a calibration of pure /3-emitters such as 3H is feas- ible, if the liquid scintillator containing the activity is looked at by two photo- multipliers. The crucial condition is that a very high percentage of even the single-photoelectron pulses are counted. This is possible only if there is a negligible fraction of secondary pulses arriving later than the dead- time following the 'true' pulses. Therefore, the decay of the luminescence was followed by means of a time-to-pulse-height converter, for delays up to 500 /us. Curiously, a flat maximum of the light intensity after about 30/us was found for all liquid scintillators, which is not present in the decay of plastic scintillators. However, the probability for an afterpulse is, for 3H, low enough to make possible a coincidence calibration as described above.

1.2. Techniques associated with standardization

(a) Influence of the delay on the coincidence counting rate. The coincidence counting rate of two different 4ir 0-y assemblies was measured precisely as a function of the delay electronically imposed between the 0- and 7-channel. Formulae based on the change of the random coincidences were derived, which describe the experimental results. The simple formula 2 r NaN2 is valid only for delays larger than the sum of dead time and coincidence resolution time.

(b) Fast testing of the performance of а 4я- proportional counter. The conventional method of measuring the integral counting rate as a function of the high voltage is very time-consuming because this entails looking for small differences between large numbers. Differential counting gives equi-

4 MEYER, K.P., SCHMID, P., HUBER, P.; Helv. Phys. Acta 32 (1959) 423. VIENNA AND SEIBERSDORF 7 valent results much faster, and the error due to counting 'spurious' pulses and rejecting 'true' pulses can be estimated.

(c) Determination of the thickness of thin layers. For thin plastic films, an a-gauge with a silicon detector was developed, which avoids the necessity of a multichannel analyser and gives a precision of ± 1 Mg/cm2. Layers of gold evaporated on plastic films were gauged by an X-ray fluorescence technique. The results were checked by activation analysis.

1. 3. Determination of constants relevant to standardization

In connection with the overall programme of radionuclide standardization, a re-determination of the half-life of 204T1 has been performed in the course of the last three years by measuring the decaying energy output of the nuclide. The microcalorimetric system developed in the Laboratory5 has been used. The provisional value obtained so far is Тг/2 = 3.6 ±0.2 years, compared with the officially recommended value T-^ = 3. 76 years. The measurements are still continuing. A paper is under preparation for publication.

1.4. Neutron fluence measurements

Monitoring of thermal and fast fluences by gold foils and sulphur pellets, respectively, was done for the Agriculture Section. The sulphur pellets were counted with an end-window GM counter, calibrated by pellets of the same geometry (21 mm diameter, 5 mm thick) pressed from unirradiated sulphur containing a definite amount of activity of 32P as (NH4)2HP04. The 32P had been calibrated by 47Г /3-counting of normal, i.e. thin, sources. The Laboratory has participated in an intercomparison of thermal flux density standards organized by the International Bureau of Weights and Measures, Paris, as a 'counting-laboratory'. The gold foils were irradiated in the AERE reactor GLEEP. The activity was measured by gamma-counting against calibrated sources. The latter were calibrated by the47r 7-coincidence method. The results from the participants have not yet been exchanged by IBPM. Because of the well-known usefulness of the103Rh(n, n')103mRh reaction for fast flux density measurements, a calibration of l°3mRh by the 4ir proportional counter-X-coincidence method was made. The ratio of the coincidences to the X-counts gives a lower limit of the efficiency for the detection of a conversion in the 47Г proportional counter. For normal and electroplated sources, apparent efficiencies between 55 and 99% were obtained. For the calibration of a routine assembly with only one thin Nal crystal, needed for the assay of thick discs of appreciable X-ray self-absorption, such discs were irradiated simultaneously with the solution, from which the thin 4тг sources were prepared.

5 SANIELEVICI, A., NAGL, J., Microcalorimètre adiabatique à compensation automatique pour mesures de la radioactivité - JARI13 (1962), 539-46 and 14 (1963) 347-50. 8 VIENNA AND SEIBERSDORF 8

1. 5. Tritium assay for the Division of Safeguards

The determination of the specific activity due to 3H, present in D20 used as moderator in reactors, was continued. Because of the unusually high precision (±0.5%) needed, a commercial liquid scintillation coincidence counting apparatus is being modified.

1. 6. Distribution of radioactive standards

In 1966 the programme of distribution of radioactive standards included two types of calibrated samples: (a) Solutions of 18 different radionuclides; (b) Sets of 8 solid-disc y-sources, which cover an energy range between 60 keV and 1. 84 MeV. The activity was increased to 10 цС1 per source, because they are widely used for the calibration of germanium detectors with low efficiencies. A total of 1851 samples was distributed to 154 institutes in 43 Member States. Details are given in Table I.

2. RADIATION DOSIMETRY

The aim of the work in Radiation Dosimetry is to establish, on an international scale, agreed standards for dosimetry so that the work of different scientists, doctors, laboratories and hospitals in the Member States may be fully intercomparable, and to this extent, more scientifically meaningful.

2. 1. Absorbed dose measurements by calorimetry

Pursuant to the work done in this subject in previous years6 an absorbed dose calorimeter made of pure reactor graphite was constructed, calibrated and put into operation. Due to the favourable physical characteristics of carbon, the sensitivity of this calorimeter is higher than the sensitivity of а 'ТЕМ' (Tissue Equivalent Muscle) calorimeter, so that it was possible to measure, in a graphite phantom, doses of 60Co gamma rays down to 10 rads per minute, with an accuracy of better than ± 2%. Upon request, measurements of central axis depth dose were performed at the 'Hôpital de Bavière' in Liège, Belgium, using high energy (20 and 24 MeV) electrons, bremsstrahlung (34 MeV) and 60Co gamma radiation. The following materials were used as absorbing phantoms: Perspex, poly- styrene, ТЕМ and graphite. The depth-dose curves, normalized to one reference phantom material, are quite consistent, within the limits set by the accuracy of the mass stopping powers and the mass energy absorption coefficients which are used as conversion factors for the calculation of the results. A paper describing these measurements is in preparation.

6 INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, First Report, Technical Reports Series No. 25, IAEA, Vienna (1964) 8. INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Second Report, Technical Reports Series No.41, IAEA, Vienna (1965) 7. INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No. 55, IAEA, Vienna (1966) 7. VIENNA AND SEIBERSDORF 9

TABLE I. RADIOACTIVE STANDARDS DISTRIBUTED DURING 1966

Total , Number of Number of Number of Type of Radionuclide activity , samples recipient Member , samples . (/jCi) distributed institutes States

Strontium-90 40 Solution 73 48 26

Zinc-65 100 Solution 56 41 22

Cerium-144 40 Solution 45 33 20

Silver-llOm 100 Solution 34 27 18

Scandium-46 100 Solution 27 22 12

Chromium-51 100 Solution 51 36 17

Thulium-170 100 Solution 37 29 18

Iodine-125 100 Solution 39 34 22

Iron-59 100 Solution 46 32 21

Americium-241 100 Solution 65 44 24

Cobalt-57 100 Solution 53 41 24

Mercury-203 100 Solution 42 29 16

Natrium-22 40 Solution 60 44 20

Caesium-137 100 Solution 93 61 29

Manganese-54 40 Solution 61 . 44 22

Cobalt-60 100 Solution 64 48 25

Yttrium-88 40 Solution 41 32 18

Sulphur-35 100 Solution 36 31 19

Americium-241 нГ Set of 8

Cobalt-57 10 calibrated

Mercury-203 20 solid 116 84 31

Natrium-22 10 ^ sources complete

Caesium-137 10 f sets

Manganese-54 10 (928 samples)

Cobalt-60 10

Yttrium-88 10 J

TOTAL 1851

Note : Altogether 154 recipients and 43 Member States were involved. 10 VIENNA AND SEIBERSDORF 10

2. 2. Ferrous sulphate (Fricke) dosimeters

In accordance with the recommendations made by many experts at the 1964 Symposium on High Energy Electron Therapy (Montreux, Switzerland) an air-freight distribution of Fricke dosimeters was organized in 19657. A paper describing the results of this first test inter comparison has been prepared for publication. In the framework of this project, a second intercomparison run was carried out in 1966 for 30-MeV electron beams from betatrons. Nine institutes in eight Member StatesS participated in this experiment, the results of which have confirmed the suitability of air-mailed Fricke dosimeters as a secondary dosimetry standard for comparison measurements of absorbed dose of high-energy ionizing radiation, in the range of 5000 rads and above. Upon request from about twenty institutes in various Member States the necessary preliminary steps for the use of Fricke dosimeters to measure absorbed doses of 60Co gamma-ray beams were made. This intercomparison was planned for March 1967.

2. 3. Lithium fluoride dosimeters

A programme is under way to establish a postal dosimetry service for radiotherapy centres in the developing countries, using the thermolumines- cent material lithium fluoride (LiF). It is expected that this service will meet the need for testing and for increasing the reliability of measurement of absorbed dose in radiotherapy patients. Development has now progressed to the stage of field interlaboratory comparisons. Results to date indicate the feasibility of this technique on a routine basis. For the first international absorbed dose intercomparison of 60Co tele- therapy units, the co-operation of twenty advanced radiotherapy centres in six countries (Australia, Canada, France, Sweden, UK and USA) was obtained. Each participating institute received from the Agency a number of LiF capsules, divided into sets of five capsules each containing some 150 mg of 'Type 7' LiF powder. Of the five capsules in each set, two are for control purposes: one, unirradiated, will detect any major background dose which the set may receive while in travel; the second was irradiated at the Agency to a known dose and will detect the decay with time of stored lumi- nescent energy in the set. The remaining three capsules were irradiated one at a time at the participating institute to a prescribed absorbed dose under specified conditions. The five capsules were then returned by air- mail to the Agency for read-out and assessment of absorbed dose. To insure uniformity in the irradiation conditions at the different radiotherapy centres, a plastic cylindrical tank (20 cm in diameter X 25 cm in height) was sent to every participating institute. The capsule to be irradiated is placed in a hole provided for this purpose in the central rod of the tank, and the tank filled with water to a marked level (see Fig. 1) which places the capsule axis 5. 0 cm below the surface of the water. The participants

7 INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No.55, IAEA, Vienna (1966) 7. 'Austria, Belgium, France, Federal Republic of Germany, Japan, Sweden,Switzerland and USA, VIENNA AND SEIBERSDORF 11 are asked to irradiate the three capsules (one at a time) from above with a 10 cm X 10 cm beam to an absorbed dose as close to 500 rads as possible. After the capsules were returned to the Agency, the light output was measured and, if necessary, corrections for background irradiation or fading are applied. Each capsule had enough powder for three light output measurements, the average of these three being called the capsule value. The precision of the system is such that the standard deviation of replicate capsule value is about 1.5%.

GAMMA-RAY SOURCE

LIF CAPSULE

FIG. 1. Standard irradiation conditions for the LiF capsules. The capsule is held at a depth of 5.0 cm below the surface of the water, and is irradiated to an absorbed dose of 500 rads with a 10 cm x 10 cm60Co beam

In the first intercomparison a total of five sets of capsules were sent to each institute. In Fig. 2 the results obtained with the first two of these sets are shown. The dots represent the means of the capsule values of the respective institutes, the ordinate scale showing the percentage difference from the overall mean. It can be seen that all the values lie within ±10% of the overall mean. The detailed data show that systematic differences among the institutes account for a substantial fraction of the observed scatter. The encouraging initial results of the interlaboratory dosimetry comparison using lithium fluoride powder justify extending the tests to radiotherapy centres in other, chiefly developing countries. The first region to be covered will be the Far East and South-East Asia: Burma, Cambodia, Ceylon, Republic of China, India, Japan, Republic of Korea, Pakistan, the Philippines, Thailand and Vietnam. Invitations to participate in interlaboratory comparisons of absorbed dose were sent to 27 radiotherapy centres in these countries.

2.4. Carbohydrate dosimeters

In connection with the IAEA food irradiation programme, a small radiation dosimetry project was carried out, consisting of the development of TABLE II. INFLUENCE OF 60Co 7-RADIATION ON THE OPTICAL ROTATION OF SOME SUBSTANCES

Experimental angle of rotation a 5% of 2% solution

Substance Irradiated to Unirradiated 0.5 Mrad Diff. 4 Mrad Diff. 50 Mrad Diff. < S Z Sucrose + 1.400 + 1.380 - 0.020 + 1.230 - 0.170 + 0.170 - 1.230 >z > Lactose + 1.245 + 1.320 + 0.075 + 1.090 - 0.155 + 0.330 - 0.915 •z a Fructose - 1.790 - 0.020 + 0.210 a - 1. 810 - 1.580 - 0.495 + 1.295 СЧ S . D-Mannitol + 0.010 + 0.010 - + 0.010 - - 1.150 - 1.160 Я сл

L-Ascorbic acid + 0.475 + 0.475 - + 0.500 + 0.025 + 0.330 - 0.145 TSI L-Tartaric acid + 0.335 + 0. 330 - 0.005 + 0.225 - 0.100 - 0.110 - 0.445

D-Camphorsulphonic acid (22%) + 4.955 + 4. 950 - 0.005 + 4880 - 0.075 + 3.700 - 1.255 VIENNA AND SEIBERSDORF 13

• 10 < UJ 2

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u. u. о

- 5 - a: aш.

- 10 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 r- ABCDEFGHI J KLMN OPQR INSTITUTES FIG.2. Distribution of capsule values relative to the overall mean. The participating institutes are arbi- trarily assigned the letters A to R

a new type of chemical dosimeter based on the change of specific rotation of carbohydrate solutions when irradiated. The purpose was to provide a dosimeter which would be more representative of a biological system than the inorganic salt systems usually employed and which would extend into the Megarad dose range usually employed in food irradiation. Several optically active organic substances were tried (Table II). Of these only carbohydrates were found to be promising. Most of the experiments were carried out on aqueous sucrose solutions at various concentrations. In these systems the change of rotation results from the decomposition of sucrose leading to formation of products of smaller or inverse optical rotation. In unbuffered solutions, the decomposition of sucrose on irradiation was found to be due to two effects: (a) the direct radiation decomposition resulting in glucose, fructose, various acids such as gluconic and glucuronic acids and other products, (b) the action of the acids formed from sucrose upon unreacted sucrose molecules causing their inversion to glucose and fructose. The equation governing the change dc of concentration с is

dc = k1+ k2[H+] с dt

in which kjis the rate constant for direct radiation decomposition at constant dose rate D/t, and k2 is the rate constant of inversion catalysed by hydrogen ions of concentration H+. It can be shown that this leads to a rather complicated dependence of the dose response upon concentration, temperature and dose rate. 14 VIENNA AND SEIBERSDORF 14

dose ( Mrad )

FIG. 3(a). Decrease of the optical rotation of buffered sucrose solutions (30%) with irradiation I = without buffer II = in 0.2 M phosphate buffer III = in 0.2 M carbonate buffer

FIG. 3(b). Decrease of the optical rotation of glucose solutions of different concentrations with irradiation I = 30% II = 15% III = 10% VIENNA AND SEIBERSDORF 15

By the addition of a buffer to the system to hold the hydrogen ion concentration small .(pH - 7), the system could be stabilized and an almost linear response be obtained. The difference between the response of buffered and unbuffered sucrose solutions is shown in Fig. 3(a). Linear curves may also be obtained with glucose solutions (buffers are not necessary in this case), however, the decrease in rotation is much smaller with glucose than with sucrose, so that glucose dosimeters would be less sensitive (see Fig. 3(b)). The results of these investigations were reported at the Symposium on Solid State and Chemical Radiation Dosimetry in Medicine and Biology, held at Vienna in 19669.

3. REFERENCE MATERIALS

The aim of this work is to provide, as a service to those Member States interested in the production of uranium oxide from low-grade uranium ores, reliable reference materials with which to check their analytical procedures.

3.1. Supply of analysed uranium ores

Four different samples (approximately 50 kg each) of low-grade uranium ores have been prepared and analysed and will be available as reference samples. The ores in question are torbernite (of Spanish and of Australian origin), carnotite (origin USA) and uraninite (origin Australia). A chemical analysis of other major and minor constituents is available. The values of the uranium contents were established by an international comparison between experienced laboratories in Australia, France, Spain, Canada, USA, Poland, South Africa and Yugoslavia. The Seibersdorf laboratory also participated. It was originally hoped that this investigation could accomplish both the certification of the uranium content and a comparison of methods of analysis. To this latter end, all laboratories were supplied with three detailed methods but it became obvious from some of the results that no reliance could be placed on determinations from laboratories which were not completely familiar with the methods, although they all had considerable experience with this type of sample. Consequently this aspect was considered secondary to the main objective of establishing the uranium content by the method on which the laboratory placed most reliance. The average values of uranium content for the various methods and samples are shown in Table III. From a consideration of the number of laboratories using each method, the thiocyanate and dibenzoyl methane procedures appear to be, at present, the two best suited for the determination of uranium in this concentration range and they both appear to be equivalent as far as accuracy and precision are concerned. At a lower concentration range, dibenzoyl methane probably has an advantage because of its higher sensitivity. It was also noted that there were differences of detail in the methods as used by the various laboratories. The necessity in the colorimetric procedure for the separation

9INTERNATIONAL ATOMIC ENERGY AGENCY, Solid State and Radiation Dosimetry in Medicine and Biology, IAEA, Vienna (1967). 16 VIENNA AND SEIBERSDORF 16

TABLE III. URANIUM CONTENT (AS % UAOG) OF REFERENCE SAMPLES OF LOW-GRADE ORES

Torbernite Torbernite Method Camotite Uraninite (Australia) (Spain)

Thiocyanate 0.473 0.314 0.420 0.377

Dibenzoylm ethane 0.470 0.314 0.419 0.376

Arsenazo 0.469 0.313 0.417 0.372

Volumetric 0.483 0.313 0.415 0.372

Fluorimetric 0.471 0.312 0.424 0.370

of uranium before the development of colour does not appear to lead to serious systematic errors. This was shown by the fact that one set of results reported was based on a different dissolution procedure as well as on a different analytical technique (potentiometric titration using dichromate as oxidant). This method requires neither the extraction of uranium nor reliance on calibration curves but nevertheless the results agreed very well with those from spectrophotometry. Boiling the sample with nitric acid, which was used in most laboratories to attack the sample, leaves in one sample as much as 80% of the material undissolved. One laboratory investigated the amount of uranium not dissolved in this treatment and found that the losses were less than 1%. With a tenfold decrease of uranium concentration in the ore, other techniques of analysis would prove a better choice, e.g. fluorimetry and activation analysis. The former technique was used by two laboratories on these samples. Although the results fell within the range of other methods the lower precision of fluorimetry makes it less suitable for a referee analysis.

3. 2. Analysed sample of uranium oxide containing trace impurities

It was hoped to obtain the material for this reference sample from a large commercial batch, to increase the chances of obtaining a homogeneous product. This proved impossible as none was found with the required concentration ranges of trace elements. A large amount was obtained as a gift of the South African Government: to this was added the appropriate trace elements in a solution of uranyl nitrate followed by precipitation of ammonium uranate and conversion to U3Og and then U02. This material was examined for homogeneity using the distribution of iron in small aliquots as a test for homogeneity. Two techniques were used, X-ray fluorescence and the orthophenanthroline spectrophotometric method and both showed an appreciable variation in iron content from sample to sample. Sieving tests showed differences in the iron concentration with regard to the sieving fraction, its concentration in fractions above 100 mesh being about twice VIENNA AND SEIBERSDORF 17 as high as in the fraction below 400 mesh. Attempts to obtain a homogeneous product by dissolution and re-precipitation of ammonium diuranate failed. Variation of the iron concentration with regard to the size of the precipitated particles was investigated and it was found that the differences first arise at this stage : when the precipitated diuranate was thoroughly mixed and then submitted to sedimentation, analysis showed an enrichment of iron in the finest fraction. As it was possible that only iron behaved in this manner the experiments were extended to include nickel and copper and, although there was a similar segregation with these two elements, differences in the concentration were much smaller. Improvement in the homogeneity of the sample might be achieved by mechanical milling and the problem is being investigated further.

4. ANALYTICAL QUALITY CONTROL

4. 1. Need for quality control of analytical procedures

Analytical chemistry provides information on the composition of materials of different kinds. A clear statement on the reliability of results is urgently required in all branches of applied and pure analysis as scientific conclusions, control of technical processes, diagnosis and therapy and important administrative and juridical decisions are often based upon the results of analytical procedures. It is therefore necessary to control the reliability of results and in particular the accuracy of results by appropriate analytical quality control measures, such as analysis of reference materials or participation in intercomparison runs. At present the availability of reference material is very limited and intercomparisons are not frequently organized for materials other than those intended for industrial or technical application. Therefore there is an ever increasing demand for analytical services of this type, particularly in the field of trace analysis. To overcome these difficulties the Agency has continued in 1966 to organize intercomparison runs involving the determination of radionuclides or the application of radiochemical methods in the assay of trace amounts of inactive elements. The following fields were covered: (a) determination of artificial and natural radionuclides in environmental and biological material; (b) determination of radionuclides for scientific purposes; and (c) determination of trace elements by neutron activation. The services offered under the 1966 programme including the number of samples distributed and the number of institutes and countries participating are summarized in Table IV. These figures reflect the wide interest in quality control in laboratories all over the world. Among the elements to be determined by neutron activation, the determination of mercury in food is of predominant interest as mercury compounds are widely used in agriculture, industry, medicine and in the laboratory. Due to the accumulation of mercury in the biosphere serious intoxications have been reported. As the suggested maximum permissible level in food is extremely low, i. e. near the natural background, analysis 18 VIENNA AND SEIBERSDORF 18

TABLE IV. IAEA ANALYTICAL QUALITY CONTROL SERVICES 1966 Programme

Number of Samples Participating Code No. Nuclide Matrix participating ordered countries laboratories

I. Environmental and biological material

66/1 Cs-137 Animal material 122 79 24

66/2 Pu-239 Vegetation 59 39 17

66/3 Rn-222 Water 75 37 19

66/4 Ra-226 Soil 58 35 19

Ra-228

II. Nuclides used in scientific investigations

66/5 K-40 Feldspar 67 49 18

66/6 H-3 Water 57 37 16

66/7 C-14 Starch 45 29 13

III. Inactive nuclides to be an alysed by neutron activation

66/8 Br Fumigated flour 27 24 15

66/9 Br Flour, untreated 24 22 15

66/10 Hg Hg treated cereals 45 41 17

66/11 Hg Cereals, untreated 43 40 17

66/12 Cu, Mn, Mo, Animal blood 40 25 20 Fe, Zn, Cr

66/13 Cu, Mn,i Mo, Animal bone 35 31 19 Fe, Zn, Cr

66/14 Cu, Mn,, Mo, Mussel shells 38 32 22 Fe, Zn, Cr

for total mercury and for individual mercury compounds is extremely difficult. Therefore an ad hoc quality control seems essential. The 1966 mercury intercomparison run, for the first time carried out on a world-wide basis, will give information on the average reliability of mercury determinations. VIENNA AND SEIBERSDORF 19

4. 2. Results of intercomparison runs

The intercomparison runs organized in 1965 were evaluated in 1966. The results of the determination of 90Sr, 137Cs, 22SRa,-potassium, calcium and inactive strontium are compiled in Table V and presented graphically in Figs 4 and 5. The data show a fairly narrow grouping of results around the mean. However, the existence of serious errors in the work of some institutes is obvious. The accuracy is less satisfactory for very low concentrations of elements such as 226Ra and inactive strontium. The determination of main food constituents, i. e. calcium and potassium is character- ized by an unexpectedly wide range of results. The reason for some part of these large variations in the determination of active and inactive nuclides must lie in the lack of an adequate analytical quality control. The reliability of 210Po determinations in vegetation, meat and bone is also relatively poor. This is believed to be due to difficulties encountered in the analysis of these rathér complex matrix materials. The results of the intercomparisons organized in 1966 are only partly available. So far only a preliminary evaluation of the analyses of animal material has been made. The results of i37Cs and potassium determinations are graphically presented in Fig. 6. They show a narrow clustering around the most probable value but again a number of results must reflect systematic errors. The report for 1967 will contain a more detailed evaluation of the 1966 exercise.

4. 3. Average reliability of environmental analysis

The intercomparisons organized from 1962 to 1966 for a number of radionuclides give a good picture of the average reliability of analytical data obtained in low-level activity measurements. To make the results of different runs comparable, individual results were normalized with reference to the most probable values of the activities taken as 100. The histograms obtained by plotting all individual normalized results at 5% intervals against the corresponding frequency of occurrence is shown in Fig. 7. The distribution of results can be taken as characteristic for the accuracy attainable in routine environmental analysis. No generality, of course, can be claimed because many different kinds of analytical difficulties are encountered in different matrices. At any rate the reliability of environmental analysis seems satisfactory for surveys aimed only at rough estimates of biospheric contamination. Whenever analytical results are used as a basis for scientific conclusions, higher accuracy is required and, to achieve this, a stricter analytical quality control scheme is essential.

5. TRACE ELEMENT ANALYSIS

Trace element analysis by radiochemical methods is an important branch of nuclear methodology. Particular use is made of neutron activation, which is a valuable tool in the determination of trace constituents in biological, mineralogical and industrial samples. The aim of the . gency laboratory to о

TABLE V. IAEA ANALYTICAL QUALITY CONTROL SERVICES Results of the 1966 intercomparisons (Values in pCi/kg or g/kg)

Number of Number of General mean Best verified values Nuclide Matrix results laboratories (95<7oC.L.) (95% C.L.)

< Cs-137 Mixed diet 177 35 355 à 170 350 ± 36 zR Sr-90 172 31 139 ± 34 136 ± 15 >z Ra-226 37 7 5.16 è 7.90 2.93 t 1.06 > z К 179 34 7.06 è 2.48 7.26 ± 0.44 a сл ra Ca 150 31 3.48 ± 1.36 3.58 i 0.34 S m Sr 49 12 (7.7 ± 15.6) X 10~3 (5. 6 è 4. 8) X 10" 3 та сл a о 70 Range of means 11

Po-210 Tobacco 27 650-2400

Po-210 Meat 21 18- 49

Po-210 Bone 23 90- 273 VIENNA AND SEIBERSDORF 21

FIG.4. Results of intereomparison run 1965 using 90Sr, 137Cs and 226 Ra (Mixed diet) has been to explore some of the ways in which the technique of trace element analysis could be brought to bear on problems of international significance. For some time, neutron activation has also been used in the analysis of forensic samples, in particular for the determination of very small amounts of poisons in human autopsy material. A well-known example is 22 VIENNA AND SEIBERSDORF 22

FIG.5. Results of intercomparison run 1965 using Ca, К and Sr VIENNA AND SEIBERSDORF 23

FIG. 6. Results of intercomparison run 1966 using К and 137Cs (Animal material) the analysis of arsenic which, due to its favourable nuclear properties, can be determined in this way with a sensitivity far exceeding that achieved by other methods. Recently, neutron activation has been used to an increasing degree also in the characterization of samples by their trace element spectrum: ten to twenty different trace elements in samples such as hair, plastics, paint, ink, glass, paper, etc. are determined simultaneously and the results used as 'fingerprints' to establish or exclude identity of samples. A number of laboratories in Member States are already engaged in this work and several 24 VIENNA AND SEIBERSDORF 24 small meetings have been held in which the potentialities of these methods were emphasized. To assist these laboratories the Agency is considering a programme to supply intercomparison samples which could be used to cross-check procedures and their accuracy. In addition, assistance might also be rendered in data-collection to determine the natural variability of the trace element composition of various matrices and allow estimates to be made of the limits of confidence within which an identification is valid. As a first step in this direction, a number of glass samples was analysed in the laboratory using neutron activation and X-ray fluorescence. In this particular case the X-ray method appeared to be the more suitable technique, allowing a rapid determination of.12-14 constituents in a single run requiring at most a few hours.

200 300

RESULTS I NORMALIZED) •

FIG. 7. Project LOW RA Frequency of occurrence for all results (Ь% intervals)

Figure 8 shows X-ray fluorescence spectra obtained with two different glass samples. Each of these samples was first examined with an organic analysing crystal (PE, the results are shown in the left half of the figure), and afterwards with a lithium fluoride crystal (LiF, right half of the figure). This procedure ensures good efficiency of detection for light (down to Z= 14) G/055 2

t t 11 ТТПТТГП n t t tt t n 11 j m tt 111 t t r+i t tt t tt t _ й: ^ — fi: — 9 9 e, .. s,.,., ., e, ¿"3 *« *В И * о* *"S * - lî * lï n и K¡ ОQ Э o ^ î СN О Q( с Ni^ ^k вQ . i ^ sо C Q It 1 t I

FIG. 8. X-ray fluorescence spectra of two different glass samples showing lines characteristic of several trace elements M сл 26 VIENNA AND SEIBERSDORF 26 as well as heavy elements. The peaks of characteristic trace elements are distinctly shown and well separated. The elements Fe, K, Ca, Zn, Ba, Ti, Ni, Sb, Sr and Zr could be identified in glass 2; in glass 3 Sb was absent, but Cr, Mn and Cu were also detected. By running suitable standards along with the unknown sample, a quantitative determination of these elements can be achieved and an identification made with a high degree of confidence. Analysis by neutron activation is rendered difficult by the large amounts of sodium contained in these samples. The radiation emitted by the fairly high 24Na activity which is formed on activation tends to mask the peaks characteristic for the other elements. Some improvement of this situation is possible by radiochemical separation or by the use of new high-resolution gamma detectors and investigation into this possibility is continuing. III. ANALYTICAL SERVICES TO MEMBER STATES

A number of analytical projects have been carried out on request of Member States who do not have their own analytical facilities for radionuclide determination.

1. TUNISIA

At the request of the Tunisian Government, about 30 samples, mainly calcium phosphate and sulphate, were analysed for uranium, thorium and radium. As the uranium concentration was in some cases as low as a few parts per million and in most cases not over 200 ppm, activation analysis was chosen as the most appropriate method available to the laboratory. A method was developed, based on the determination of 239[\ф which is formed from23SU on neutron bombardment. Very good agreement was obtained between the results so obtained and those obtained by the Tunisian authorities using a fluorimetric method. Thorium was also determined by activation analysis, in this case estimating the 233pa formed on neutron capture of and beta decay from 232Th. Radium was determined by comparison of gamma- ray activities with a standard radium source. It was clear that the uranium deposits in the area concerned were subject to considerable leaching as the uranium and radium were not in radioactive equilibrium. The radium content of one sample corresponded, if in equilibrium, to 12% uranium, whereas the actual content was less than 5 ppm. Thorium was also determined in the low-grade uranium ore reference samples, in case these samples should be used for the radiometric method for uranium.

2. VENEZUELA

On request of the Instituto Venezolano de Investigaciones Científicas (IVIC), at Caracas, Venezuela, the Agency assisted the Institute in drawing up an environmental monitoring programme to establish radionuclide levels around its nuclear facilities during the first year of their operations. As part of this assistance the Agency also undertook to analyse samples collected under this programme. Samples of soil, grass, water, bottom dregs and bone were analysed for 90Sr and137Cs. The results were communicated to the institute.

3. THE SUDAN

A large number of air filters and gummed papers, which had been exposed by the Sudanese Meteorological Services at several stations in the Sudan, were received with a request to determine gross beta radioactivity. This was done using automatic counting equipment.

27 IV. CHEMICAL AND PHYSICO-CHEMICAL INVESTIGATION RELEVANT TO THE AGENCY'S PROGRAMME

1. ANALYTICAL CHEMISTRY IN THE SAFEGUARDS PROGRAMME

It will obviously be a major task of the Laboratory to provide expert technical help to the Safeguards Programme of the Agency. Here the aim has been to develop and refine the analytical procedures which will be necessary for the Laboratory to fulfill that task. The method for the accurate titrimetric determination of uranium, previously described10 and its modification using a coulometric end point11 require quite large-sized samples (5 g) to obtain high precision and accuracy. Since such samples may not always be available, the precision for smaller samples was determined. Using the coulometric modification, a Coefficient of variation of 0. 03% was obtained for 0. 5-g samples compared with 0.0006% for 5-g aliquots. For the determination of uranium and plutonium, constant potential coulometry is now an accepted method and is very useful for small samples. Using this technique a mean relative error of + 0. 1% for copper (0. 5- to 1-mg sample) and ±0.2% for uranium (5- to 10-mg sample) were obtained in agreement with the literature. It was noted that the stirring rate and type of stirrer have a considerable influence on the duration of the determination.

2. ANALYTICAL CHEMISTRY IN THE LIFE SCIENCES PROGRAMME

A number of samples of different whale organs as well as squid tissues from Iceland, the Atlantic and the Mediterranean, which had been collected in the course of research on the accumulation of trace elements in marine organisms were sent to the Vienna Headquarters by the Agency's Laboratory of Marine Radioactivity at Monaco. Gamma emitters were to be determined in these samples, since in most cases their activities were too low to allow an accurate determination at the Monaco institute. Identification of radionuclides by gamma spectrometry was followed by radiochemical separation and determination. Radionuclides identified in all or some of the samples were 40K, 54Mn, 65Zn and137Cs. In some samples 0. 2 pCi S4Mn/g of ash were determined in the presence of up to 100 pCi each of65Zn and 40K.

"INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Second Report, Technical Reports Series No.41, IAEA, Vienna (1965). "INTERNATIONAL ATOMIC ENERGY AGENCY. IAEA Laboratory Activities, Third Report, Technical Reports Series No. 55, IAEA, Vienna (1966).

28 VIENNA AND SEIBERSDORF 29

Of the whale organs measured, liver seems to be able to concentrate Zn and Mn to a considerable degree. This is apparent in Fig. 9, which gives the gamma spectrum of the whale liver sample showing considerable 54Mn and 65 Zn activities. In the other whale organs analysed 54Mn was much lower and 65Zn was below the limits of detection (0. 2 pCi/g of ash). Analyses for Cu, Ni, Mn and Fe have been carried out in a set of samples from the Monaco Laboratory, and for Ag in another set.

CHANNEL NUMBER ENERGY (MeV)

FIG. 9. Gamma spectrum of whale liver sample showing Mn, Cs, К and Zn activity

2. 1. Determination of iodine in blood

In continuation of the work on the determination of protein-bound iodine (PBI) in blood plasmad the development of an improved activation analysis method was completed. The main points of improvements were:

(a) Use of gel filtration instead of ion exchange for the separation of PBI from inorganic iodine prior to irradiation; (b) Wet ashing of the irradiated proteins in a chromic — sulphuric acid medium with addition of iodine carrier in the form of potassium iodate; this allows the estimation of the chemical recovery by an iodometric titration procedure; (c) Use of ferrous sulphate instead of phosphorous acid for the reduction of iodate to elementary iodine. (d) Counting of 128I in the liquid sample rather than as silver iodide; this allows reproducible self-absorption and geometrical conditions.

Table VI summarizes the results of a comparison between chemical and PBI-determinations by activation analysis carried out on commercially

12INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No. 55, IAEA, Vienna (1966). 30 VIENNA AND SEIBERSDORF 30

TABLE VI. RESULTS OF PBI DETERMINATIONS BY CHEMICAL METHODS AND BY NEUTRON ACTIVATION ANALYSIS

PBI (pg

Standard I 1.7 1.7 2.18 0.34 20.0

Standard II 7.1 7.5 8.84 1.60 22.5

Standard III 12.0 11.6 14.60 2.46 20.5

Note: A - Nominal value (manufacturer) В - Result of chemical determination С - Result of activation analysis

available standards. The chemical method used, which includes a separation of PBI from inorganic iodine by ion exchange, dry ashing of the proteins and final determination of the iodine by means of the conventional Ce4+-AsO|- reaction, is the technique used also by the manufacturer of the standards, so that the results can be directly compared (an original set of reagents from the company concerned was used). The values obtained, using this method, are in good agreement with those given by the manufacturer. In contrast to this result there is a considerable difference between the values of PBI determined by chemical means and those obtained by activation analysis. This difference expressed in per cent of the standard values given by the manufacturer seems to be independent of the absolute PBI-concentration. For three different standards investigated (low, medium and high level) the difference found was 21. 0 ± 1. 0%. A full explanation of this behaviour (some references have appeared in the literature) is not yet possible. Since the activation method was tested thoroughly with tracer techniques without finding any systematic errors which could explain the difference, efforts are now concentrated on a check of the chemical procedure. There is an indication that losses do, in fact, occur on the ion exchanger. The exact chemical identity of the PBI fraction is, after all, not well established and it may be that the retention, or decomposition under retention of iodine, of a component of this fraction occurs on the exchanger. The final experiments which are to be carried out before the project is terminated are di- rected at the confirmation of this possibility.

3. STUDIES ON DECOMPOSITION UNDER RADIATION STERILIZATION

The radiation decomposition of folic acid (pteroylglutamic acid) has been investigated at the request of the Division of Life Sciences as it was VIENNA AND SEIBERSDORF 31

considered that there was insufficient information on the behaviour of this member of the vitamin-B group during gamma-ray sterilization. In general, it is known that folic acid is more resistant to irradiation damage than the other group В vitamins when they are contained in food. However, some destruction of folic acid is to be expected and this could lead to the formation of substances having enzyme-inhibiting properties. It is known that 2-amino- 4-hydroxypteridine-6-aldehyde, 4-amino-N10 methyl pteroylglutamic acid and 2, 4-diamino-6-formyl-pteridine, all derivatives of folic acid, are inhibitors of several enzymes. The effect of gamma irradiation of folic acid was studied in solution and in the solid state using ultra-violet and infra-red spectroscopy, paper and thin-layer chromatography and electron spin resonance. Irradiation of folic acid in 0. 001N NaOH solution leads to radiation decomposition proportional to the dose from 0.5 -2.5 Mrad. At the lower limit 24% and at the upper over 67% of the folic acid was decomposed. Decompo- sition was less in ethyl alcohol solution. Chromatographic analysis of the irradiated acid and its decomposition products showed that irradiation leads mainly to the rupture of the Cg-N10 bond. This was shown by the presence of pteridines and a derivative of p-amino-benzoyl glutamic acid among the radiolysis products. It was possible to identify also 2-amino-4-hydroxy-6-formyl-pteridine (one of the strongest inhibitors of folic acid) which indicates that the hydrogen atoms of position 9 and 10 of the folic acid are abstracted under irradiation. The radical thus formed may react with an oxygen atom forming a carbonyl bond. Furthermore the OH radicals attack the pteridine ring with the formation mainly of xanthopterine and other products. Folic acid is much more stable to irradiation in the solid state and no apparent decomposition, as evidenced by ultra-violet spectra and paper and thin-layer chromatography, was observed. A comparison of the infra-red spectra before and after irradiation showed only very minor differences. Electron spin resonance spectra showed that free radicals are however formed. At 4 Mrad their concentration was 1. 8 X 1015 spins/g and at 8 Mrad 2. 1 X 1015 spins/g.

4. PURITY OF COMMERCIAL RADIOCHEMICAL PREPARATIONS

Studies of the self-radiolysis of some commonly used radiopharma- ceuticals were reported in the Third Laboratory Report, when work on 1311- labeHed Rose Bengal was reported. This work was continued with an exa- mination of 131I-labelled thyroxine. These studies all arise from the suspicion that specification purity standards for the commonly used radiopharmaceutical preparations are badly needed. The Agency's Laboratory here plays an exploratory rôle, to con- firm or deny this suspicion. Labelled thyroxine (tetra-iodothyronine) is used in the study of the metabolism and transport of endogenous thyroxine in humans and to determine the nature and amount of thyroxine-binding protein in plasma. Samples were obtained from foür of the principal commercial suppliers (here designated A,B, С and D) and analysed by thin-layer chromatography. 32 VIENNA AND SEIBERSDORF 32 paper electrophoresis and 7-spectrometry. Analyses were carried out 1, 7, 17, 26 and 33 days after receipt of the samples to follow autodecomposition and other changes with time. The first analysis showed that the decomposition of samples A and В was less than that of the other two. From the autoradiographs of the chromatograms, the thyroxine content of A was 75 - 80% while that of В was approximately 60%. There was a negligible concentration of di-iodothyronine. For С and D, however, clear indications of tri- and di-iodothyronine in addition to thyroxine were obtained. After seven days of storage, the formation of lactic derivatives of thyroxine was observed and in samples В and С the amounts of di-iodothyronine increased. The decomposition of sample A was less than the others, especially sample D, where a main part of the radioactivity appeared to be due to inorganic iodine and the oxidation products of the alanine chain. With further storage the autodecomposition increases. In addition to the formation of di- and tri-iodothyronine, small amounts of di-iodotyrosine were observed. Formation of inorganic iodine reached a maximum after 17, 8 and 17 days (approximately) for samples А, С and D respectively. With sample B, the main part of the activity, after 26 days storage, corresponded to di- iodothyronine but after 33 days, the main fraction corresponded again to tetra-iodothyronine. This behaviour suggests re-iodination, as has been observed by other workers. A possible reaction mechanism is as follows. During the first days of storage, the thyroxine undergoes de-iodination,probably from position 3' resulting in the formation of tri- and di-iodothyronine. Parallel with the de-iodination, an oxidation of the alanine chain takes place leading to de-amination and to the formation of tri- and di-iodothyronine derivates of lactic acid. At the same time, an oxidation of the iodide ion to iodine takes place and the latter re-iodinates the lower iodothyronines. V. NUCLEAR ENERGY APPLIED TO AGRICULTURE

1. SOIL FERTILITY, IRRIGATION AND CROP PRODUCTION

1. 1. Co-ordinated rice project

1.1.1. Field experiments

The 1966 field programme involved a field experiment which was carried out by research contracts in 15 different locations in various rice growing Member States including Burma, Ceylon, the Republic of China, Hungary, India, Italy, the Republic of Korea, Madagascar, Pakistan (East and West), the Philippines, Thailand and the UAR. The experiment compared the efficiency of various nitrogen sources, using lf>N-labelled material, and their effect on the utilization of 32P-labelled superphosphate.

Results. The complete treatment of data will be published in a forthcoming report covering five years of co-ordinated research on the efficient utilization of fertilizers by rice. There is a striking uniformity in the outcome of the experiments as illustrated by the data in Table VII. The per cent nitrogen in the grain derived from the nitrogen fertilizers is generally of the same order of magnitude when (NH4)2S04 and urea are used. Application of these two sources two weeks before primordial initiation is at least as efficient as shallow placement at 5 cm depths at transplanting time in all locations and appreciably more efficient in at least three locations. Nitrate sources are less efficient than NH4 sources, particularly when applied at transplanting time. The efficiency of NHj NOjj is higher when the fertilizer is applied later during the growing season but not as high as (NH4)2S04 or urea. NaN03 is very inefficient for rice cultivation; the uptake from the fertilizer when it is applied at transplanting is extremely low and late application still results in very little fertilizer utilization. The utilization of phosphorus from superphosphate applied on the surface at transplanting is not significantly affected by the nature of the nitrogen source and its method of application. This is illustrated in Table VIII which gives the fertilizer phosphorus in the leaf samples taken two weeks after the last nitrogen application was made. In addition a limited number of field experiments were carried out in Ceylon, Hungary, the Philippines and Thailand to study the efficiency of depth of placement of 15N-labelled nitrogen fertilizer and the effect of nitrification inhibitor on the utilization of nitrogen from the fertilizer by the rice crop. Table IX lists the per cent nitrogen in the samples that was derived from the fertilizer for the experiments that were carried out in the Philip- pines and Thailand. The experiment in Ceylon was not completed in 1966. In the case of both experiments it is evident that surface placement in rows

33 34 VIENNA AND SEIBERSDORF 34

TABLE VII. CO-ORDINATED FIELD EXPERIMENT ON THE EFFICIENCY OF NITROGEN UTILIZATION FROM VARIOUS FERTILIZER SOURCES (% N in the grain derived from fertilizers)

Surface, two .weeks before primordial 5 cm depth at transplanting initiation Country

(NHJSSO,, Urea NH4NO3 NaN03 (NH^SQ, Urea NH4NO3 NaN03

Ceylon 17.2 20.2 8.4 4.5 19.9 24.8 12.8 6.9

East Pakistan 14.9 11.2 8.6 1.5 24.2 21.3 16.7 10.3

Hungary 11.6 5.9 7.1 0 10.5 8.0 5.2 3.0

Italy 14.8 16.6 9.6 1.0 17.5 18.3 13.7 4.7

Philippines 14.0 19.2 12.9 1.7 19.6 19.1 15.3 8.1

Rep. of China 15.1 20.1 13.9 3.2 30.3 22.7 25.7 13.2 (Taichung)

Rep. of China 13.4 11.1 7.7 2.6 35.4 21.2 19.0 7.9 (Taipeh)

Rep. of Korea 19.0 19.4 10.5 1.3 20.1 24.7 15.5 3.4

Thailand 40.5 34.2 22.7 5.3 44.3 32.8 26.0 26.2

UAR 12.6 12.3 5.1 0 13.8 18.3 11.3 3.9

West Pakistan 28.8 15.7 11.7 0 14.7 20.8 14.4 7.1

Notei Data for Madagascar, India I and II and Burma are being analysed. and broadcast on the surface result in the same utilization of nitrogen from the fertilizer. The utilization of surface-applied nitrogen is however small as compared with shallow placement. The per cent nitrogen in the grain derived from fertilizer is not significantly affected by the depth of placement and therefore there would not be any justification in applying the fertilizer deeper than 5 cm. The effect of the method of applying the nitrogen on the utilization of phosphorus from superphosphate is given in Table X. The phosphorus contents and per cent phosphorus in the plants that was derived from the fertilizer are listed for two experimental sites. In the Philippines, the soil phosphate availability is very high and in Thailand soil phosphorus is extremely deficient. In the case of the Philippines it may be seen that the phosphorus content in the plants is high, 0.17 - 0.20%. All the depth placements of nitrogen resulted in a significant decrease in phosphorus utilization from superphosphate applied on the surface. In Thailand, the phosphorus content of the plants is low, even after the application of superphosphate. The variability of the data is much greater and no significant effect of depth of nitrogen applications on the utilization of phosphorus from superphosphate applied 35 VIENNA AND SEIBERS DORF

TABLE VIII. CO-ORDINATED FIELD EXPERIMENT ON THE •EFFICIENCY OF UTILIZATION OF SURFACE-APPLIED SUPERPHOSPHATE AS AFFECTED BY NITROGEN SOURCES AND METHOD OF NITROGEN APPLICATION (% P in the leaf samples — at primordial initiation - derived from fertilizers)

Surface, two weeks before 5 cm depth at transplanting primordial initiation Country

(NH4)2S04 Urea nh4no3 NaN03 (nhjjso,, Urea nh4no3 NaNO,

Burma 8.6 10.8 9.0 8.8 9.8 10.6 9.2 10.8

Ceylon 27.6 16.6 18.7 11.3 10.2 20.7 13.5 19.6

East Pakistan 45 45 38 38 42 43 41 48

Hungary 16.7 12.3 15.8 10.8 13.3 11.3 12.9 10.8

India (Cuttack) 16.2 16.2 18.7 16.9 24.5 18.9 18.7 15.3

India (Hyderabad) 61,0 54,0 61.3 63.1 67.3 62.5 64.5 18.8

Italy 8.8 8.4 9.1 9.1 7.6 8.9 8.0 9.1

Philippines a 25.2 21.8 24.6 19.7

Rep. of China 19.7 18.5 22.7 24.0 25.7 28.3 27.7 19.6 (Taichung)

Rep. of China 6.2 8.4 8.2 7.6 8.3 7.7 7.8 7.2 (Taipeh)

Rep. of Korea 11.3 12.2 22.3 16.2 15.0 17.4 16.2 14.8

Thailand 39.4 40.4 40.4 30.1 40.0 31.2 29.2 33.1

UAR 20.4 20.9 17.2 14.9 20.5 23.1 21.1 17.0

West Pakistan 57.2 54.0 55.5 51.1 57.2 60.9 55.9 53.3

a Samples were taken 2 weeks before primordial initiation.

Notei Data for Madagascar are being analysed.

on the surface could be detected. It is evident from Table XI that all surface applications of (NH4)2 SO4 resulted in a less efficient utilization of nitrogen by the crop than shallow placement. Compared with tropical regions, however, the magnitude of losses of gaseous nitrogen due to denitrification processes is small on account of the low temperatures during the spring in Hungary. 36 VIENNA AND SEIBERS DORF

TABLE IX. FIELD EXPERIMENT ON THE UTILIZATION OF NITROGEN FROM (NH4)2S04 AS AFFECTED BY DEPTH OF PLACEMENT (% N in the grain derived from fertilizer)

N The Philippines Thailand treatment

Surface broadcast 7.1 11.8

Surface in rows 8.3 11.2

Rows, 5 cm deep 18.5 32.4

Rows, 10 cm deep 19.3 37.0

Rows, 15 cm deep 21.6 38.1

TABLE X. FIELD EXPERIMENT ON THE UTILIZATION OF SURFACE-APPLIED SUPERPHOSPHATE AS AFFECTED BY METHOD OF NITROGEN APPLICATION

The Philippines Thailand N treatment % P d.f.f. a <7o P % P d. f. f. a , °lo P

Surface broadcast 9.2 0.17 18.5 0,096

Surface in rows 8.8 0.17 22.3 0.099

Rows, 5 cm deep 5.9 0.18 18.6 0.098

Rows, 10 cm deep 5.4 0.19 20.1 0.091

Rows, 15 cm deep 5.2 0.20 18.8 0.091

H.S.D. № 2.1 0.004 not sign. not sign.

a "¡o P d. f. f. = °¡o P in the plants derived from fertilizers.

1.1.2. Greenhouse experiments

A number of greenhouse experiments were carried out using the soils corresponding to the sites of field experiments. The greenhouse experiments dealt with nitrogen balance, comparisons of nitrogen sources in relation to timing and the effect of nitrification inhibitor on nitrogen utilization from nitrogen fertilizer. These special experiments serve the dual purpose of investigating specific problems raised by the co-ordinated pro- 37 VIENNA AND SEIBERS DORF

TABLE XI. FIELD EXPERIMENT ON THE EFFECT OF NITRIFICA- TION INHIBITOR 'AM1 ON THE UTILIZATION OF (NH4)2S04 BY RICE

(% N in the plants derived from (NH4)¿304)

Leaf samples Treatment #„ ,%r Grain (60 a)

(NH4)2S04 at 5 cm depth, without AM 36 23

(NH4)2S04 surface, without AM 29 18

(NH4)2S04 surface, + 2 kg AM/ha 32 19

(NH4)2S04 surface, + 4 kg AM/ha 25 14

TABLE XII. GREENHOUSE EXPERIMENT COMPARING THE EFFICIENCY OF NITROGEN SOURCES, APPLIED AT DIFFERENT TIMES (% N in the plants derived from fertilizer — 70 days after seeding)

<Уо N derived from fertilizer Relative units Country Source Seeding 20 d 40 d 50 d Seeding 20 d 40 d 50 d

(NH4)2S04 38 42 48 52 73 80 92 100 Thailand NH.NO, 32 33 45 54 59 61 83 100 (pH4.2) 4 3

NaN03 24 29 47 49 49 59 96 100

(NHJ2S04 37 43 51 56 66 77 91 100 Madagascar NH.NO, 28 38 40 45 62 84 84 100 (pH 4. 8) 4 3

NaN03 8 20 37 47 17 42 79 100

(NH^SO, 25 27 34 33 76 82 103 100 Philippines

NH4NO3 15 19 24 31 48 .61 77 100 (pH 6.5) NANOJ 2 7 25 31 6 23 80 100

(NH4)2S04 25 33 50 44 57 75 113 100 UAR NIbNOs 16 25 42 40 40 62 105 100 (pH 8.5)

NaN03 6 16 36 39 15 41 92 100 38 VIENNA AND SEIBERSDORF

TABLE XIII. GREENHOUSE EXPERIMENT ON THE EFFECT OF • AM' AS A NITRIFICATION INHIBITOR ON THE PER CENT NITROGEN IN PLANTS DERIVED FROM (NH4)2S04 (% N in plants derived from fertilizer — 67 days after seeding)

Level of applied AM in kg/ha Soil 0 2 4

Thailand 54 54 52

Burma 56 45 46

Philippines 27 28 27

Madagascar 47 49 46

Ceylon 42 43 50

UAR 29 30 32

gramme and also provided small training projects for Fellows who received awards under the Agency's Fellowship Programme. Table XII lists the per cent nitrogen in the plants that was derived from the fertilizer. All four soils showed that the late timing of each of the three sources was more efficient than early application. Early in the growing period (NH4>2S04 is much more efficiently utilized than the two other sources. There is, however, a rapid increase in utilization of NH4N03 and NaN03 after 40 - 50 days. Although the results seem to suggest that at the end there is little difference in utilization of NH4 and NOs sources, this should be interpreted with caution. In a pot experiment the degree of utilization of nitrogen from nitrogen fertilizer is always much higher than in the field due to the fact that the amount of soil that can be explored by the root system is limited. In fact, the results of the field experiments which were reported under section 1.1.1 showed that in the field the utilization of nitrate sources by rice is considerably less than that of NH4 sources. The observation that the efficiency of N03 sources increases when the fertilizer is applied later • in the growing season holds however for both field and greenhouse studies. As far as the experiment on the effect of nitrification inhibitor on the utilization of NH4 from surface-applied (NH4)2 S04 is concerned, Table XIII shows that inhibitor AM13 had no effect on the utilization of nitrogen from the fertilizer. Finally, Table XIV related to the comparison of the efficiency of various phosphate fertilizers on different rice soils, shows for the various sources the number of grams of fertilizer phosphate which is equivalent to 100 g phosphorus in superphosphate. The data show that K-metaphosphate + MgS04 and K-orthophosphate are more available than superphosphate on all soil types tested. K-pyrophosphate and K-metaphosphate were less available than superphosphate on all soil types.

13 AM = a nitrification inhibitor supplied commercially by Tokyo Kyatso Co. VIENNA AND SEIBERSDORF 39

TABLE XIV. GREENHOUSE EXPERIMENT COMPARING THE AVAILABILITY OF VARIOUS DIRECTLY LABELLED PHOSPHATE SOURCES TO RICE (Grams of fertilizer P equivalent to 100 g P in superphosphate)

Thailand Burma G Brazil Burma M UAR Fertilizer (pH 4.5) (pH 5.0) (pH 6.7) (pH 7.8) (pH 8.5)

K-metaphosphate 88 118 50 87 75

+ MgS04

K-pyrophosphate 141 182 174 109 104

K-metaphosphate 180 164 86 110 155

K-orthophosphate 64 82 69 58 74

Superphosphate 100 100 100 100 100

It is quite striking that the availability of phosphorus from K- metaphosphate can be greatly increased by mixing the fertilizer with MgS04. More research is needed to explain this mixing effect. The analyses of 32P,31P, 14N, andl5N in the plant samples were carried out in the Laboratory, using techniques previously described.14 The labelled fertilizers required for the field programme were weighed out and despatched by the Seibersdorf Laboratory. Similar services were provided for the Co- ordinated Maize Project described in section 1.2.

1.2. Co-ordinated maize project

The 1966 programme dealt with the completion of the analyses of the field experiments that were carried out during the later part of 1965 and beginning of 1966. The experiment which was carried out by contractors in Argentina, Colombia, UAR, Peru and Brazil had the following objectives:

(a) To study the effect of different times of application of ammonium- sulphate on the utilization of fertilizer nitrogen by maize; (b) To study the effect of mixing and separate placement of nitrogen and phosphorus fertilizers on the utilization of fertilizer nitrogen and phosphorus.

In January 1966, a new field experiment was designed at a contractors meeting in Bogota, Colombia, which was partly carried out during 1966 and dealt with the application of nitrogen split up into two or three doses during

17INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No.55, IAEA, Vienna (1966) 67. 40 VIENNA AND SEIBERS DORF the growing season and the relative contribution of the nitrogen from the fertilizer from each dose. In addition, the mixing effect of nitrogen and phosphorus fertilizers on nitrogen and phosphorus utilization from the fertilizers was investigated. Participating countries were: Argentina, Brazil, Colombia, Ghana, Mexico, Romania, Peru and the UAR. A special field experiment was carried out in Austria (Harrach farm, Bruck a/d Leitha) to investigate the relation between rate of nitrogen and phosphorus applications on the magnitude of the mixing effect of both fertilizers as revealed by the per cent nitrogen and per cent phosphorus in the plants derived from fertilizers. A second field experiment was carried out at the Harrach farm to study the efficient use of nitrogen from ammonium sulphate as affected by time and distance of side dressing. Table XV shows the results of the field experiment on the efficiency of utilization of nitrogen and phosphorus fertilizers as affected bytime of side dressing and mixing of nitrogen and phosphorus fertilizers, i. e. the per cent nitrogen in the grain that was derived from the fertilizers for the various treatments, in five countries. With the exception of Argentina, where the weather was extremely dry, all countries show side dressing at or before tasseling to be much more efficient than banding or plow down at seeding time. It is likely that spring temperature, rainfall distribution and absence or presence of irrigation facilities affect the magnitude of the side-dressing effect. More research is needed to evaluate these factors. The mixing of nitrogen and phosphorus fertilizers did not have any effect on the utilization of nitrogen from the fertilizer but had a pronounced positive effect on the utilization of phosphorus from superphosphate (TableXVI). Table XVII shows the per cent nitrogen in the grain that was derived from fertilizers for Colombia, the UAR and Ghana. The analyses for Mexico, Peru, Argentina and Romania are still in progress. According to TableXVII, the later side dressings contribute much more to the fertilizer nitrogen in the grain than do the earlier applications. Mixing nitrogen and phosphorus had no effect on the utilization of nitrogen from the fertilizer. However, the effect of mixing nitrogen and phosphorus on the utilization of phosphorus from the fertilizer was very pronounced as may be seen from Table XVIII. Mixing generally results in a much greater utilization of phosphorus from superphosphate than separate placement of nitrogen and phosphorus. The per cent nitrogen and phosphorus in the plants that was derived from the fertilizer are shown in Table XIX. Increasing doses of phosphorus at the high nitrogen level increased the per cent nitrogen in the grain derived from fertilizer and similarly an increase in utilization of phosphorus from the fertilizer was found when the rate of labelled nitrogen application increased. The effect of hill drop placement was pronounced for the utilization of phosphorus from the fertilizer; hill drop, generally results in a much higher utilization of phosphorus from superphosphate than banding. No such effect was evident for the utilization of fertilizer nitrogen. The effect of mixing, as illustrated by a comparison of two of the treatments (30 N, 15 P) shows that the phosphorus uptake from the fertilizer is greatly enhanced by mixing nitrogen and phosphorus fertilizers. The mixing effect on phosphate uptake 41 VIENNA AND SEIBERS DORF

TABLE XV. CO-ORDINATED FIELD EXPERIMENT WITH MAIZE ON METHOD AND TIME OF APPLICATION OF NITROGEN

(% N in the grain derived from (NH4)2S04)

Treatments Time Argentina Colombia UAR Peru Brazil

A. N and P mixed in band Seeding 23.1 25.4 17.6 38.4 27.7

B. N and P separated in band Seeding 23.4 22.5 19.1 34.7 25.4

C. N plough down P in band Seeding 20.1 18.6 20.4 23.6 27.2

D. N side dress Height at 50 cm P in band 50 cm 15.6 38.4 36.5 46.3 33.7

E. N side dress Between at 50 cm height 50 cm P in band and tasseling 16.3 49.7 42.0 42.8 39.0

F. N side dress at 50 cm P in band Tasseling 10.3 44.8 46.0 46.5 33.2

G. N side dress 10 days at 50 cm after P in band tasseling 3.5 34.2 37.3 32.3 23.5

was greater for hill drop than for banding treatments. No mixing effect was found for the nitrogen derived from the fertilizer. NaNOs appeared to be of availability similar to (NH4)2S04. Striking however is the depressing effect of NaNOa on the utilization of phosphorus from superphosphate. Another experiment was carried out at the Harrach farm on the effect of distance and time of side dressing on the utilization of nitrogen from (NH4>2S04. Table XX gives the results in terms of per cent nitrogen in the plants that was derived from the fertilizer. It may be seen that side dressing at a distance of 15 cm was the most efficient placement, resulting in the highest utilization of nitrogen. The time of side dressing had little effect, but both side dressing at a height of 50 cm and just before tasseling time are much more efficient than banding at seeding time. It is evident that leaf samples and straw samples are not a good indicator for the comparison of side dressing effects. Apparently the fertilizer that is applied during 42 VIENNA AND SEIBERS DORF

TABLE XVI. CO-ORDINATED FIELD EXPERIMENT WITH MAIZE ON THE EFFECT OF MIXING NITROGEN AND PHOSPHORUS FERTILIZERS ON THE UTILIZATION OF PHOSPHORUS FROM SUPERPHOSPHATE (% P in plants derived from fertilizers)

N, plough down Country Sampling N,P mixed N,P separated P, in band

Argentina Height 25 cm

Height 50 cm 21.2 13.1

Between 50 cm and tasseling 18.8 10.9

Colombia Height 25 cm 23.5 10.4

Height 50 cm 16.2 4.4 5.8

Between 50 cm and tasseling 12.9 3.5 6.8

Peru Height 25 cm 34.6 16.3 14.0

Height 50 cm 35.5 8.0 11.0

Between 50 cm and tasseling 27.5 6.4 7.1

Brazil Height 25 cm 88.1 32.4 66.

Height 50 cm

Between 50 cm and tasseling 38.7 29.7 34.2

the growing period of the maize is mainly transported to the grain and not to the leaves. Only when the nitrogen is applied at seeding time (banding) is the 15N content of straw and grain identical.

1. 3. Co-ordinated research programme on tree crop fertilization

Based on the recommendations of the Consultant Group on the Use of Isotopes in Studies on the Fertilization of Plantation and Orchard Crops (Vienna, November 1965) a co-ordinated programme has been initiated to study the distribution of active roots in different tree crops using 32P, as a preliminary step in the study of the various factors affecting fertilizer utilization. A series of standard experiments is being planned in different countries to study the root distribution (both in terms of area and depth of 43 VIENNA AND SEIBERS DORF

TABLE XVII. CO-ORDINATED FIELD EXPERIMENT ON RATE OF APPLICATION AND TIME OF SIDE DRESSING OF NITROGEN

(% N in grain derived from fertilizer)

Treatments of N Colombia UAR Ghana

A. 50 50 a 18.1 9.2 13.2

B. 50 50 35.6 14.8 22.4

C. 33 33 33 b (mixed with P) 6.8 6.4 8.0

D. 33 33 33 (not mixed with P) 6.9 5.1 8.8

E. 33 33 33 22.0 8.8 17.0

F. 33 33 33 29.7 15.3 8.9

3 50 kg N/ha labelled with 15N banded, 50 kg as side dress at 50 cm height, k 33 kg N/ha labelled with 15N banded, 33 kg non labelled as side dress at 50 cm height and 33 kg non labelled as side dress at tasseling.

TABLE XVIII. CO-ORDINATED FIELD EXPERIMENT ON THE EFFECT OF MIXING NITROGEN AND PHOSPHORUS FERTILIZERS ON THE UTILIZATION OF PHOSPHORUS FROM SUPERPHOSPHATE (% P in plants derived from superphosphate)

Sampling at 20 cm height Sampling at 50 cm height Country N,P mixed N,P separated N,P mixed N,P separated

Colombia 46.1 29.6 29.7 18.1

Mexico 0.26 0.26 7.8 2.2

Romania 46.4 27.0 21.0 7.5

Ghana 53.5 46; 2 38.1 40.6

UAR 1.29 0.89 2.14 0.92

Peru 40.1 13.2 33.0 11.7

soil round the tree) of various tree crop species in relation to soil type, age of tree, season, and interline vegetation. The experimental technique consists of injecting 32P in rings round the trees at four different distances and four different depths, with four replica- tions. The 32P solution is dispensed into ampoules at the Seibersdorf La- 44 VIENNA AND SEIBERS DORF

TABLE XIX. FIELD EXPERIMENT ON THE EFFECT OF RATE AND METHOD OF APPLICATION OF (NH4)2 S04 AND SUPERPHOSPHATE ON THE UTILIZATION OF FERTILIZER NITROGEN AND PHOSPHORUS BY MAIZE

Treatments % N in grain % P in plant derived Rate of application derived from from fertilizer in (N kg/ha) (P kg/ha) Method of placement fertilizer plants of 50 cm height

10 5 Hill drop 3.9 0.3

Banding 3.1 0.2

30 5 Hill drop 9.1 1.2

Banding 10.1 0.25

90 5 Hill drop 24.3 0.4

Banding 22.1 0.15

10 15 Hill drop 3.7 2.7

Banding 4.6 1.3

30 15 Hill drop 11.1 7.5

Banding 10.0 2.1

90 15 Hill drop 26.7 4.5

Banding 27.5 3.4

10 45 Hill drop 4.2 7.8

Banding 3.9 3.3

30 45 Hill drop 12.5 18.2

Banding 10.4 3.1

90 45 Hill drop 32.4 17.0

Banding 30.2 12.4

30 15^ Hill drop 9.9 1.5

Banding 10.4 0.7

30 15 b Hill drop 9.9 0.6

Banding 8.8 0.7

a N and P not mixed.

b N as NaNOj. 45 VIENNA AND SEIBERS DORF

TABLE XX. FIELD EXPERIMENT ON DISTANCE AND TIME OF SIDE DRESSING OF (NH4)2S04 (%Nin plants derived from fertilizer)

Sample 50/50 a T/50 b 50/15 T/15 Banding

Leaves (tasseling) 17.2 5.3 15.3 12.7 10.2

Straw 10.9 9.9 18.3 12.1 13.3

Grain 17.1 17.2 25.2 22.8 13.9

a 50/50: height of maize 50 cm, distance of application: 50 cm from plant row. *> T/50: application just before tasseling, at a distance of 50 cm from plant row. boratory and supplied to the participants. A total of about 5 m Ci 32P is injected per tree. The specific activity of phosphate in leaves of the same physiological age is used as a measure of phosphorus uptake to assess treatment differences. Comparison of the relative specific activity for the different treatments will enable a "root map1 to be plotted. Where necessary, the 32P analysis of samples is carried out in Seibersdorf. In 1966 contracts were made for research on coconuts in the Philippines, coffee in Kenya, and olives in Tunisia. Already preliminary experiments have been commenced to study leaf sampling techniques in relation to the physiological age and morphological position of leaves. Further experiments will be carried out in Spain (citrus), Nigeria and Malaya (oil palm), Ghana (cacao) and Ceylon (coconuts).

1. 4. Co-ordinated programme of plant nutrient supply and movement in soils

The laboratory work was mainly concerned with the study of nitrogen chemistry in soil. A greenhouse trial was conducted to study the availability of a number of nitrogen fertilizers on different soils. A second greenhouse experiment dealt with the so-called 'priming' effects of nitrogen fertilizers on the soil nitrogen supply. In view of the rapidly growing importance of 15N studies for agricultural purposes, a method of analysis of 15N using an optical emission spectrometer was worked out in co-operation with the Chemistry Section (see section IV-4. ). Particularly in developing countries the purchase of expensive mass spectrometric equipment for agricultural purposes is hardly justified on account of its high cost and the need for highly specialized staff. The use of optical emission spectrographic equipment, which is generally available in agricultural research institutes, opens now possibilities for large-scale investigations involving the use of 15N-labelled material. The results of the greenhouse experiment on the efficiency of utilization of various nitrogen materials on different soils are given in Table XXI, 46 VIENNA AND SEIBERS DORF

TABLE XXI. GREENHOUSE EXPERIMENT ON THE EFFICIENCY OF UTILIZATION OF VARIOUS NITROGEN MATERIALS ON DIFFERENT SOILS

(mg N in the shoots derived from fertilizer)

Urea Urea (5 cm) (NH.JJSO, NH4NO3 NaNOj Country DM a mg N b DM mg N DM mg N DM mg N DM mg N

Yugoslavia 1.51 33 2.47 58 1.74 52 1.11 42 0.42 13

Brazil 1.11 33 1.50 42 0.99 30 1.52 48 0.76 18

UAR 0.78 13 1.19 22 0.88 14 0.73 15 0.43 11

Austria 1.69 38 1.99 47 1.43 27 1.30 31 1.34 36

a DM: Dry Matter of shoot in grams, b mg Ni milligrams of nitrogen. which shows the wide variation in dry matter production that was found for the different sources. The highest dry matter production was generally found when urea was placed at a depth of 5 cm. This corresponds with the highest fertilizer nitrogen uptake by the crop: NaN03 is much less available than the other nitrogen sources, as demonstrated by the low dry matter production and low fertilizer nitrogen uptake. The efficiency of urea, (XH4)2S04 and NH4N03 as applied on the surface was about the same for most of the soils. The second greenhouse experiment mentioned above has shown that an increasing rate of nitrogen application generally increased the dry matter production, the quantity of nitrogen taken up from the fertilizer and the quantity of nitrogen supplied by the soil (Table XXII). The increase in rate of nitrogen fertilizer application did not, however, alter the availability of the soil nitrogen supply, as may be seen from the last column of Table XXII, where the AN values expressed in ppm nitrogen are listed. This AN value was calculated from the formula AN = В (l-y)/y in which В is the rate of fertilizer nitrogen application and у the fraction of the nitrogen in the plant that was derived from the fertilizer. The у value was determined as the ratio of 15 N excess of fertilizer and plant material. The results of this experiment show clearly that there has been no significant priming effect of nitrogen fertilizer on the availability of soil nitrogen, i. e. the soil nitrogen is supplied to the plants at a constant rate and is not affected by the rate of fertilizer nitrogen applications.

2. DETERMINATION OF NITROGEN-15 CONCENTRATION IN NITROGEN

The adaptation of the Hilger Watts model 742 emission spectrograph to measure 15N concentration in nitrogen for agricultural purposes was re- 47 VIENNA AND SEIBERS DORF

TABLE XXII. GREENHOUSE EXPERIMENT ON THE EFFECT OF RATE OF NITROGEN FERTILIZER APPLICATION ON THE AVAILABILITY OF SOIL NITROGEN (AN)

N derived Rate of N Dry matter N derived from fertilizer AN Soils application production from soil (g) in shoots (ppm) (kg/ha) (mg) (mg)

_ 0 0.42 _ 13 50 2.08 14 33 61 Brazil 100 2.09 27 31 55 200 3.06 72 44 61

0 2.38 - 33 - 50 4.15 11 49 112 Argentina 100 4.54 27 56 104 200 5.76 67 63 95

0 0.98 - 31 - 50 1.88 8 52 159 Romania 100 1.60 12 41 162 200 2.02 28 46 163

0 0.78 - 13 - 50 1.78 4 23 123 UAR 100 1.44 9 23 122 200 1.60 • 24 27 116

0 2.05 - 30 - 50 3.38 13 35 69 Colombia 100 4.27 37 47 65 200 4.53 72 47 65

0 2.03 - 39 - 50 2.75 15 48 77 Austria 100 2.08 25 45 91 200 1.74 34 30 85

0 0.34 - 12 - 50 0.75 4 23 141 Peru 100 0.78 7 18 123 200 0.53 10 9 106

0 1.31 - 13 - 50 2.48 12 22 47 Mexico 100 3.02 32 28 45 200 2.36 54 25 46

0 1.05 - 11 - 50 1.63 9 17 46 Yugoslavia 100 2.87 27 26 49 200 3.19 64 29 47 48 VIENNA AND SEIBERSDORF 48 ported in the last Laboratory Report. 15 The difficulty arising from the insufficient brilliance of the lines has been overcome. A further difficulty, that of an apparently varying background due to overlap of the 15N-14N and the l4N-14N lines was solved by a more careful alignment of slits. In collaboration with the Agriculture Section, the apparatus has been put into routine use, as the accuracy is entirely sufficient for agricultural research with the low 15N enrichments used. Table XXIII shows a comparison of results by optical and by mass spectrometry. Each determination, with two scans of the relevant lines, lasts 15 minutes. The cost of the apparatus is much less than that of a mass spectrometer. In special cases the optical method has a real advantage over mass spectrometry in that the minimum sample required is 10-100 times smaller, i.e. a few micrograms of nitrogen. This work has been prepared for publication.

TABLE XXIII. ATOM PER CENT EXCESS OF 15N IN 10 RANDOM MAIZE SAMPLES FROM COLOMBIA

Optical spectrometry Mass spectrometry

0.83 0.851

0.04 0.034

0.61 0.614

0.79 0.786

0.72 0.789

0.73 0.735

0.44 0.431

0.66 0.636

0.49 0.484

0.48 0.486

3. ENTOMOLOGY

These studies aim to promote to the fullest possible extent the introduction of the sterile-male technique to Member States which suffer economic loss or human disease through the action of entomological pests, which might be attacked by this technique, and to solve some of the practical problems in the mass-rearing of sterile males.

17INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No.55, IAEA, Vienna (1966) 67. 49 VIENNA AND SEIBERS DORF

3. 1. Mediterranean fruit fly

3.1.1. Release of sterile flies in Vienna (in collaboration with the Austrian Federal Institute for Plant Protection)

Owing to a weather-induced population minimum in 1965 and 1966, after the peak reached in 1964, sterile irradiated flies were released in only one orchard in 1966. They seemed to move out of this orchard much more rapidly than in 1965, perhaps because they were released as adults and not as pupae. The relative survival and movement of flies released as adults should be compared with that of flies released as pupae in future trials. Fruit was attacked in two suburbs of Vienna in 1966. This outbreak will probably increase in 1967.

3. 1.2. Aerial release of sterile flies (in co-operation with the Citrus Marketing Board (CMB) of Israel)

An improved version of the tube for releasing sterile insects from aero- planes was built at the laboratory and field-tested in Israel.

3. 1.3. Movement of released sterile flies in the field (in co-operation with the CMB of Israel)

Rates of movement of adult flies released on the ground and in the air from paper-bags were observed in Israel. There was some evidence that aggregations of such flies may block the movement of wild flies. If this effect is strong enough it may be valuable to set up high concentrations of sterile flies on the borders of treated areas to repel immigrants.

3. 1.4. Selection of superior strains of Mediterranean fruit fly

After about 16 generations of selection there did not seem to be much useful increase in activity or longevity in the selected strain. Hybridization of diverse strains may be a better way of increasing adult vigour.

3.1.5. A fluid medium for mass rearing Mediterranean fruit fly larvae

A fluid medium which could be pumped, shaken and drained would assist the mechanization of Mediterranean fruit fly rearing. Its composition could be varied to meet the changing needs of the developing larvae. This is not possible with existing media. The problem was tackled in two phases: (a) the major nutritional requirements were estimated, and (b) practical methods were developed.

(a) Major nutritional requirements, survival and growth of larvae

(i) Most deaths occur in the first three-days after hatching; (ii) Undercrowding increases the death rate in the early stages of development; 50 VIENNA AND SEIBERS DORF

(iii) More than 80% of the total carbohydrate-protein uptake is carbohydrate in the first 3 days of life, but between the 6th and 9th day almost 60% of the uptake is protein; (iv) Extracts of dried carrot accelerated growth. The active principle seems to be carotene.

(b) Rearing on a fluid medium

Three generations of Mediterranean fruit fly have been reared on an agitated fluid medium containing yeast and sucrose but this method is still in course of development. The medium must be given at a carefully controlled rate to avoid drowning.

3. 2, Olive йу

The progress of work on larvae media for olive fly was retarded by the low fecundity of adult stocks. This trouble was also found in earlier years and may be a result of unsuitable lighting. The influence of light on feeding, mating and fecundity must be investigated.

3. 3. Tsetse fly

The flies were fed through artificial 'Parafilm' membranes but could not be sustained on citrated, heparinized or defibrinated ox or pigs blood.

4. GENETICS AND PLANT BREEDING

4. 1. Research on mutation induction in agricultural crop plants

The purpose of these investigations is to increase the efficiency of mutagen treatments in mutation production and thereby to increase the possibilities of developing new strains having an enhanced economic or nutritional value. The experiments have also been aiming at finding treatments which could modify and reduce the non-genetical or physiological injuries of mutagen treatment in the Мг plants such as growth inhibition, death, steri- lity and other deleterious effects. The results of these experiments will be the basis for advice, guidance and service treatments of seed material to plant breeders in Member States.

4.1.1. Experiments with ionizing radiations

Experiments were carried out with gamma radiation using a S0Co gamma cell available in the Austrian Institute for Atomic Energy and with neutrons using the Austrian swimming pool reactor (ASTRA). Both fast and thermal neutron radiations have been used. A special container was constructed for seed irradiation, where the gamma and thermal neutron irradiations were shielded off by thick walls of lead and a layer of boron, so that the main effect of the radiation in the seeds came from fast neutrons. VIENNA AND SEIBERSDORF 51

Several experiments have been carried out comparing radiosensitivity and the relative biological efficiency (RBE) of gamma, thermal and fast neutron irradiations . Seedling growth tests showed that dry barley seeds with a moisture content of 13% were much more radiosensitive to neutrons than to gamma rays.*6 The RBE for gamma rays versus neutrons was approximately 40. No difference was found between thermal and fast neutrons, the same dose in each is required to produce the same effect on seedling growth. In addition to the barley variety Himalaya, which has been mostly used in these experiments, a large number of varieties of rice, wheat and barley from various parts of the world have been irradiated and compared for their radiosensitivity to various kinds of ionizing radiations.

4. 1, 2. Effects of various pre- and post-irradiation treatments

The purpose of these experiments was to reduce the physiological damage of irradiation to embryos, to improve germination, plant growth and survival, and thereby obtain higher mutation frequencies after irradiation exposures. The ultimate goal of these experiments is to study possible increases in mutation rates and changes in the mutation spectrum. Samples of dry seeds of Himalaya barley were irradiated with 30 krad and 50 krad of gamma radiation, and 700 rads of fast neutrons. Irradiated and non-irradiated seeds were placed in buffers of pH 7, 11, and 3, for 2 to 24 hours and compared with the same post-treatments in water. The seeds were then tested for seedling growth in the growth chamber. The main results can be summarized as follows: The post-treatments in the buffers pH 7 and 11 caused a significant reduction in radiation injury, while at pH 3 the damage had increased. The stimulating effects of pH 7 and 11 appeared first after 2 hours treatment. The optimum was found to be 6 hours. A positive effect could be observed up to 18 hours of post-treatment. Longer post-treatment times had a deleterious effect. The buffer of pH 11 was more effective than that of pH 7. The main results are presented in Fig. 10.

4.1.3. Experiments with chemical mutagens

Several chemical compounds have been shown to have considerable mutagenic effects on plants. The effects of some compounds were studied and their use as supplement mutagens to ionizing radiation in practical breeding was evaluated. In 1966, the chemical mutagens diethylsulphate (DES) and ethylmethanesulphonate (EMS) were investigated. The barley variety Himalaya was used as experimental material and the seedling growth test was used to study the effective concentration, treatment time and temperature and other factors that might influence the efficiency of the mutagen treatment. Samples of dry seeds and seeds that were pre-soaked in water from 2 to 24 hours, were treated with DES solutions, in water and in various buffers.

17INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No.55, IAEA, Vienna (1966) 67. 52 VIENNA AND SEIBERS DORF

Except for dry seeds, in all pre-soaked series, 0. 02 M DES seems to be the optimal concentration; higher concentrations were toxic to the plants. It was found that short pre-soak times (2 to 8 hours), caused little damage to seedling growth while 12 to 24 hours pre-soaking showed much more pronounced seedling injuries, indicating that the seeds were in a more sensitive stage.

140 О IN WATER

IN PH 11 120 - \V w

t— X 100 § i i 1 Ш X о z 80 - —1 n 1 UJ 1 1 ! 1 i 1 IlJ 1Л 60 - S s s s s <о I- UJ S s s s s 40 - crо UJ S s s 20 - ^ 1 1 1 1 s\ \\ \\ \\ s s 8 12 16 20 24

FIG. 10. Effect of post-treatment in buffer, pH 11, as compared to water

The effects of treatment temperature (from 5 to 35°C) and duration were also studied. The experiments indicated that if the mutagen treatment was carried out at higher temperatures and short treatment exposures, less seedling injuries were observed. When the treatment .time was less than 1 hour (at 30 to 35°C) there appeared to be no advantage in using DES in a buffer solution. When the treatment time was longer than 1 hour, less injury was obtained when DES was applied in a buffer solution. On the basis of the results of these experiments, a limited number of DES treatments were selected for mutation studies and treated seeds planted out in the field. Seeds pre-soaked for 5 hours and 15 hours were treated with 0.02 M DES solution for 30 minutes at35°C (see Table XXIV). After the treatment the seeds were washed in flushing tap water for 1 hour. Half of the material was sown out soon after the treatment, while the other half of the seeds were dried back to normal moisture content (approximately 13%) and stored for 5 days at room temperature before planting out in the field. All treatments showed almost normal germination and plant survival. Only a slight reduction in seed setting of treated seeds as compared with the untreated controls could be observed. All the plants were harvested and spike progenies were grown in the greenhouse for chlorophyll mutation analysis. Whole spikes were laid out for germination in vermiculite. The 53 VIENNA AND SEIBERS DORF

TABLE XXIV. CHROMOSOME ABERRATIONS AFTER DES-TREATMENTS AND GAMMA RADIATION

Treatments % damaged cells No. of fragments/cell No. of budges/cell

Untreated controls 0.5 0.015 0.02

Gamma radiation

15 krad 54.0 1.02 30

DES 0.02 M 1/2 hour at 35" С

5 h pre-soak, H20, wet 26.5 0.39 14.3

5 h pre-soak. Hp, dry-back 33.4 0.67 8.6

5 h pre-soak, pH 7, wet 21.8 0.33 11.3

5 h pre-soak, pH 7, dry-back 27.7 0.46 5.1

15 h pre-soak, НгО, wet 20.2 0.33 3.7

15 h pre-soak, HjO, dry-back 17.2 0.30 3.0

15 h pre-soak, pH 7, wet 19.2 0.28 3.2

15 h pre-soak, pH 7, dry-back 17.2 0.28 3.0

chlorophyll mutations were analysed in the M2 seedlings. The results are presented in Tables XXV and XXVI. It can be concluded from the results of these analyses that after a pre- soak of 15 hours the seeds were in a very sensitive stage and gave a much higher mutation incidence than those pre-soaked for 5 hours. The dry-back storage treatment nearly doubled the mutation frequency. DES treatments with pre-soak and dry-back storage have not been previously reported in the literature. The mutagenic effectiveness of DES was found to be higher in treatments with pre-soaking and dry-back storage, than without the pre- treatment of seeds. A similar series of experiments were carried out with EMS. The results were similar to those from the DES experiments, and some EMS treated seeds were included in the field material for mutation studies. The results from the chlorophyll mutation analysis are also presented in Tables XXV and XXVI. The effects of the dry-back storage were much higher than in the DES experiments. Mutation frequencies increased in the 0. 5% EMS series from 5. 7 to 21.6% and from 4.9 to 40.4% after 5 and 15 hours pre-soaking time, respectively. 54 VIENNA AND SEIBERS DORF

TABLE XXV. THE EFFECTS OF GAMMA RADIATION AND THE CHEMICAL MUTAGENS ETHYLMETHANESULPHONATE (EMS) AND DIETHYLSULPHATE (DES) ON CHLOROPHYLL MUTATIONS IN BARLEY

„, Number of seedlings Number of mutations Treatments , ° per spike per 100 plants

Gamma radiation

15 Kr 8.3 13.5

20 Kr 10.8 21.4

EMS

0.3%- 5 h pre-soak - dry 20.4 6.3

0.3% - 15 h pre-soak - dry 20.4 5.4

0.5%- 5 h pre-soak - dry 20.6 21.6

0.5%- 5 h pre-soak - wet 19.7 5.7

0.5% - 15 h pre-soak - dry 20.1 40.4

0.5% - 15 h pre-soak - wet 21.6 4.9

1.0%i- 5 h pre-soak - wet 20.6 23.6

1.0% - 15 h pre-soak - wet 21.0 30.5

DES

5 h pre-soak - dry 21.4 10.2

5 h pre-soak - wet 22.0 7.3

15 h pre-soak - dry 18.6 31.9

15 h pre-soak - wet 21.0 17.5

4.1.4. Cytological investigations on chromosome aberrations after mutagen treatments

The various mutagen treatments are also being investigated with respect to their cytological effects on chromosome aberrations. A rapid squash method for the preparation of microscope slides of barley shoot tips, using Feulgen's fuchsin stain has been developed. The effects of the different 55 VIENNA AND SEIBERS DORF

TABLE XXVI. CHLOROPHYLL MUTATION SPECTRA AFTER , GAMMA-IRRADIATION, EMS AND DES TREATMENTS

Treatments Albina Xantha, Alboviiidis Viridis Others a

Gamma radiation 33.2 3.2 45.6 17.8

EMS 17.7 12.0 53.9 16.3

DES 32.3 16.7 38.9 12.4

a Includes the chlorophyll types: Tigrina, Striata, Maculata, and Dark green.

treatments were studied in the anaphases of the first mitotic division in the shoot meristem (Fig. 11). The effects of gamma radiation and DES were analysed and the results are presented in Table XXIV. The most interesting findings were:

(a) Applications of DES at pH 7 resulted in slightly lower, chromosome aberration frequencies than when the DES is applied in water; (b) The aberration frequencies were higher in the short pre-soak series (5 hours) than in the long (15 hours) series; (c) A considerable increase in fragment frequencies and concurrent decrease in bridge frequencies were found after dry-back storage in the short pre-soak series, while no differences were found in the long pre-soak series.

These results show that the chlorophyll mutation incidences are not related to the degree of chromosome damage after DES treatments.

4.1.5. Field experiments

An essential step in the evaluation of mutation methods is the testing of material under field conditions. Experiments with cereals: In co-operation with Adams of Harrach's plant breeding station and Nagl of the Bundesanstalt fiir Pflanzenbau und Samenprüfung, a large number of mutagen treatments of barley, wheat and durum wheat were grown in the field. A series of doses of gamma and fast neutron irradiations and various treatments of the chemical mutagens DES and EMS, separately or in combination with a radiation treatment, were compared. During the growing season observations were made on germination, plant growth, plant survival and fertility. On the basis of the chlorophyll mutation test that was performed in the greenhouse in the fall and winter, progenies from the most promising treatments were selected for planting out in the field in spring 1967. 56 VIENNA AND SEIBERSDORF

FIG. 11. Chromosome aberrations (fragments and bridges) from gamma radiation and chemical mutagen (DES) treatments

Experiments with rice; With the co-operation of ORKI, Hungary, some preliminary field experiments were carried out at Szarvas. The rice seeds were given the various treatments of gamma and neutron irradiation and the chemicals EMS and DES.

4. 1.6. Neutron seed irradiation programme

In the framework of the Agency's programme on neutron seed irradiation, the laboratory has participated in developing a 'biological dosimeter' for the dosimetry of neutrons in reactors. The seedling culture technique in the growth chamber 17 has especially been developed for this application. A large number of experiments have been carried out to evaluate the biological effects of contaminating gamma radiation and thermal neutrons in the reactors. These experiments have been very important in the final design of the facilities and equipment that should be used for neutron irradi-

17INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities. Third Report. Technical Reports Series No.55, IAEA, Vienna (1966) 67. 57 VIENNA AND SEIBERS DORF ation of biological material in reactors. It is hoped, by the development of this standard neutron irradiation facility, to clear up some of the discrepancies existing in the work of many radiobiologists, geneticists and agricultural scientists throughout the world, and so to permit the reporting and intercomparison of their irradiation conditions in a standardized, reproducible way not at present possible.

4. 2. Mutagen service treatments

The laboratory gave research contractors, co-ordinated mutation research projects and UNDP/ТА plant breeding projects advice and service treatments of seeds. Seeds of rice, wheat, barley, beans and tomatoes have been given mutagen treatments with gamma and neutron radiation and also with EMS and DES. These services have been provided to plant breeding institutes in Member Countries in Africa, Asia, America and Europe.

5. FOOD IRRADIATION

The investigations on certain aspects of food irradiation were intended as a practical contribution to the joint SGAE/ENEA/Agency International Programme on Irradiation of Fruit and Fruit Juices. The work was concerned with radiation effects on enzymes, such as pectinmethylesterases (PME), polygalacturonases (PG), and cellulases, which affect texture changes in tissues of horticultural products. The temperature dependence of the activity of PME from several fruits and vegetables was studied. Other investigations were done on the resistance of PME in solution and in the solid state to gamma irradiation.

5. 1. Effect of gamma irradiation on several horticultural products

A method was worked out for a precise determination of PME-activity before and after gamma irradiation, by titration at constant pH value with 0. IN NaOH. Samples were irradiated to a gamma dose of 1. 1 Mrad. A number of products (apples, pears, peaches, grapes, oranges — albedo and flavedo layer —, bananas, strawberries, plums, tomatoes, potatoes, paprikas, onions, carrots, mushrooms, green beans and peas) were investigated in this way. They showed the distribution of the enzyme-activity to depend on the state of the enzyme in the cell (whether free or attached to particles) and the degree of homogeneity of the sample. After solubilization, the enzyme activity in the solubilized pulps was not found to be higher than in the non-solubilized pulps (except for bananas, where the activity was 30% higher). The activity of the solubilized juices (obtained from the solubilized pulps) was somewhat higher than the activities in the non-solubilized juices. Gamma-irradiation led to different effects in pulps and juices of different fruits and vegetables. In bananas, peaches and carrots PME activity increased on irradiation; in apples, paprikas and potatoes it was found to 58 VIENNA AND SEIBERS DORF

E (I.u./ml)

FIG. 12. Dependency of EDS0 on the PME-enzyme concentration decrease. In mushrooms and grapes PME-activity was too low to allow any comparison. Similar investigations were made on pears, plums, grapes, tomatoes, and paprikas. The samples had been previously stored tor one year at -20°G The enzyme activities of the stored products, measured at 30° С were slightly lower than those in fresh ones; when measured at 50° C, the enzyme activities of the stored products were twice as high as those of the corresponding fresh products.

5. 2. Temperature dependence of PME activity

In former investigations it was shown that the temperature optimum for PME activity determination is 50° C. Non-solubilized and non-irradiated pulps of various fruits were used and the determinations were carried out at 30 and 50° C. The results show that in the case of fruits the PME-activity at 50° С is twice as high as at 30° C; for vegetables it is 1. 3 times higher at the higher temperature. For fresh tomatoes and paprikas, the temperature optimum appears to be at 30° C. For tomatoes and paprikas stored for the period of one year at -20° С the temperature optimum is again 50° C.

5. 3. Effect of gamma irradiation on PME

In order to investigate the radioresistance of PME to gamma irradiation, enzyme preparations were made from fresh tomatoes. A procedure was developed for the purification of tomato PME. Many bands were obtained by paper electrophoresis of tomato proteins, but only one band contained all PME activity. The radioresistance of the various products was determined by irradiation at several dose levels to calculate the dose necessary to reach 50% inactivation (ED50). While ED50 was found to be around 3 Mrad 59 VIENNA AND SEIBERS DORF for a direct extract from tomato at 20 i. u. /ml PME concentration, a puri- fied solution of the same PME-activity showed an ED50 of only 0. 09 Mrad. The ED50 values are a function of enzyme-concentrations and amount of 1 impurities' (Fig. 12). Irradiated solid PME is more radioresistant than PME suspended in a buffer solution.

5. 4. Determination of cellulase activity

Various Na-carboxymethyl cellulose preparations were tried as substrates for cellulase. Experimental conditions for polygalacturonase (PG) determinations were investigated and the PG activities of a series of enzyme concentrations tested with different substrates. The effect of gamma irradiation on aqueous enzyme solutions of various concentrations and on solid enzyme preparations was also studied. VI. NUCLEAR ENERGY Ш MEDICINE

The 1966 programme in the field of medical applications of nuclear energy had three broad goals: (i) development of techniques and instrumentation to increase the usefulness of radioisotopes in medical diagnosis, radiotherapy and research; (ii) assistance to specific laboratories in Member States by provision of training and information on techniques and by supplying special radioisotope preparations; and (iii) conduct of research having special relevance to the Agency1 s interest. Within these areas the following accomplishments during 1966 may be summarized: (i) Techniques for interlaboratory comparison of absorbed dose measurements in radiotherapy have been developed and tested (see section П-2. 3. ). Discriminating techniques for instrumental neutron activation analysis have been developed. Collimators for diagnostic radioisotope scanners have been systematically compared. Techniques for whole-body counting have been further developed and generalized to a wide range of instrumentation. Certain problems in the statistics of radiation measurement have been analysed, (ii) Initial steps have been taken to organize a postal service for testing of radiotherapy dosimetry in developing countries (see section II-2. 3. ). Labelled proteins have been prepared and distributed to laboratories collaborating with the Agency in a study of protein metabolism in malnutrition. Training has been provided in whole-body counting techniques. (iii) Further progress has been made in the study of radiation toxicity in humans as exemplified by persons with internal burdens of Thorotrast.

1. DEVELOPMENT OF TECHNIQUES AND INSTRUMENTATION

1. 1. Medical activation analysis

The medical activation analysis programme for measuring trace elements in medical samples, which was started last year, has been further developed. This programme aims at exploring the scope and limitations of a technique that is finding increasing application throughout both the developed and the developing nations as a powerful analytical tool in experimental medicine. The Section1 s interests have centred largely on the use of procedures which allow many trace elements to be measured concurrently after a minimum of chemical processing. To this end, an evaluation has been made of the performance of a two-parameter gamma spectrometer in recording the activities which are induced in human tissue samples by irradiation with thermal neutrons. The spectrometer responds selectively to those radioisotopes within the source which decay with the emission of cascade gamma rays. The energies deposited coincidentally in two similar Nal(Tl) crystals, oriented symmetrically with respect to the source, are recorded uniquely in a two-dimensional array of 64 X64 storage locations (channels).

60 61 VIENNA AND SEIBERS DORF

TABLE XXVII. ELEMENTS MEASURED IN LIVER SAMPLE WITH TWO-PARAMETER SPECTROMETER

Activation Approximate concentration Element Half-life product in human liver (|ig/g wet tissue)

Bt Br-82 36 h 2

Co a Co-60 5.3 yr 0.06

Cs Cs-134 2.3 yr 0.6

Fe a Fe-59 45 d 185

Na a Na-24 15 h 1400

Pa P-32 b 14.6 d 2700

Sb Sb-124 61 d 0.2

Sc Sc-46 85 d -

Zna Zn-65 250 d 46

Cla Cl-38 37 m 1250

Cu a Cu-64 13 h 9

Mna Mn-56 2.6 h 1

a Essential element in man. k Detected by means of bremsstrahlung.

Experiments on small samples of human liver, activated in the Seibers- dorf ASTRA reactor for about 5 hours in a flux of 1013 thermal neutrons cm"2 s"1, have revealed that several trace elements can be determined without recourse to prior radiochemical separations. By following the gamma- ray spectra over a period of several weeks, starting a few hours after the end of the activation, the elements listed in the upper part of Table XXVII can be determined. Typical spectrometer displays (Fig. 13) from unprocessed tissue samples show, upon detailed analysis, peaks attributable to 60Co, 134Cs, l24Sb, 46Sc and 65Zn present in the samples several weeks after activation. Although analysis of a single sample is completed only after several weeks, many samples can of course be run in the same concurrent series. The trace elements listed in the lower part of Table XXVII can be studied by variations of these methods. Copper and manganese can be identified after a simple and rapid chemical separation employing an anion-exchange resin. Experiments are under way, however, using activation periods of a few minutes to establish whether these elements cannot be determined directly, without radiochemistry, from measurements started shortly after the end of the irradiation. During the next year, the ability to measure these and other trace elements in unprocessed samples is expected to be greatly increased. The 62 VIENNA AND SEIBERS DORF

FIG. 13. Two-parameter analyser displays from unprocessed human liver 10 weeks after activation with thermal neutrons. The displays are taken from the same spectrum at two different levels of contrast enhance- ment. The diffuse circular areas of increased illumination (diameter ~ 3 channels) represent y -y -coincidence 'peaks', and are ascribable to ®°Co, 134Cs, 1J4Sb, "sc. and 85Zn within the activated liver technical promise for this work of Ge(Li) solid state detectors has been explored and a unit of 20 cm3 size ordered. By virtue of an energy resolution of 5 keV for gamma rays of 1 MeV, such a device should allow many additional trace elements to be identified. It is expected to be particularly useful for determining those radioisotopes which, because they do not emit coin- cident gamma rays, are not favourable cases for measurement with the two- parameter gamma spectrometer. As a practical test of these procedures, a programme has been initiated for studying trace-element concentrations in tissues in relation to various disease conditions and environmental factors. It is intended to study the liver in particular, since this is the most important storage organ for most trace elements in the body, and is probably most responsive to changes in the trace element content of the diet and to the disease. Preliminary investigations are in progress for studying the levels of trace elements in the liver, and their uniformity of distribution throughout the organ, for normal persons.

1. 2. Radioisotope scanning

The laboratory' s programme for the study and comparison of radioisotope scanning systems has been continued. These devices are among the most widely used instruments in clinical radioisotope centres. Several commercial products are available. The radiation detection unit consists of a sodium iodide crystal to which a multi-hole radiation collimator is fitted. However, a wide range of crystal diameters (3, 5, 7, 8 inches) and of collimator designs is commercially offered, and the lack of comparative information on performance impedes the selection and effective use of these instruments. The objective of this investigation is to explore methods for comparing the performance of crystal-collimator systems and to make such data available as a service to medical institutes and hospitals in Member States. 63 VIENNA AND SEIBERS DORF

The principal physical parameters of a collimator are its depth response along the collimator axis, its spatial resolution as a function of depth, and its sensitivity. These can be investigated with the help of a ' line source' of a radionuclide, the source being moved in a plane perpendicular to the collimator axis (Fig. 14). The count rate is recorded as a function of the line-source position relative to the collimator axis. This yields the line- source response of the collimator at a particular source-plane-to-collimator distance. From the integration of the line-source response, the plane-source sensitivity of the collimator is obtained.

FIG. 14. Experimental set-up for measuring the line-source response at various distances from the face of the collimator. Length of line source is 30 cm, length of path perpendicular to collimator axis is also 30 cm. Speed of movement is 0.5 cm/min. (A Picker 5-inch diameter crystal-collimator is shown instead of the 3-inch collimator used in the measurements reported)

A source holder was constructed which moves the line source at a constant slow speed (Fig. 14). About 60 minutes are required for the complete 30 cm sweep of the line source in a single plane. The detector- collimator head remains in a fixed position (axis horizontal) and need not be attached to a scanner. The line source consists of a 30-cm plastic tube filled with a radioactive solution. The inside diameter of the tube is 1. 5 mm, and the total activity is about 8 mCi. For the numerical recording of the count rate a 400-channel analyser is used in the multi-sealer mode. Pulses within the photopeak (as selected by an auxiliary single-channel analyser) are accumulated during a fixed period (15 s) in each successive channel. After completion of each run the contents of all channels are printed out numerically. The results obtained from such measurements may be exemplified by a particular set: Picker =jf= 2107 collimator (19 holes, 8. 2 cm focal length), 3 in. diam. X2in. Nal(Tl) crystal, 1311 source (364 keV), photopeak counts (energy range 330 - 410 keV). In Fig. 15 is shown the response to the line source in air. The count rate (% of maximum) is plotted as a function of the lateral displacement of FIG. 15. Une-source response of Picker ф 2107 collimator: experimental data for various source-plane-to- collimator distances with1'11 line source in air using 330-410 keV spectrometer window. Collimator resolution distance and plane source sensitivity are given for each depth VIENNA AND SEIBERSDORF 65 the line source from the collimator axis for various distances between source plane and collimator. Curves are shown for each of seven distances between source plane and collimator. While the data of Fig. 15 were recorded in air, in all clinical situations some of the space between source and collimator is occupied by an absorbing medium. The latter will modify the depth response of the collimator, making it less sensitive to sources at increasing depths within the absorbing medium. An effective gamma-ray absorption coefficient can be derived by dividing the depth response within the absorbing medium by that in air. It was found to be 15% lower than the theoretical absorption coefficient, a discrepancy attributable to the inclusion within the photopeak of some gamma rays scattered at small angles. For many scanning applications the spatial resolution of a collimator is of even greater importance than the depth response. The collimator resolution for the source plane in question is defined as the full width at half maximum (FWHM) of the line-source response. The observed resolution distances at each depth are shown in Fig. 16. Within the accuracy of the measurement the resolution at a given distance was the same for the source in an absorbing medium as in air. The resolution distance observed with severed collimators for the 3-inch diameter crystal is given in Fig. 16 as a function of depth. These collimators have their optimum resolution

40 x **2107A-19 hole (henagonal)

x #2107 -19 hole (round) / x w2102 -31 hole (round) x

о 2 6 8 10 12 U 16 18 Source-to-collimator distance (cm) FIG. 16. Resolution (FWHM) of three Picker focusing collimators as a function of depth for 131I line source. In addition, the resolution of a scintillation camera (Nuclear-Chicago) obtained with1311 and M3Hg point sources is indicated 66 VIENNA AND SEIBERS DORF

(smallest FWHM) at a depth of about 7. 5 cm. The change of collimator resolution with depth is greatest for the collimator with the best resolution. With the parallel-hole collimators used for scintillation cameras, the best resolution is observed at small depth. The resolution of one such collimator as a function of depth is included in Fig. 16 for the135 and 203Hg gamma rays. The third important collimator parameter is its sensitivity. Since the 30-cm-long line source is moved over a 30-cm distance, the total scan represents a plane source of 900 cm2. The integrated counts can be expressed as counts per minute per microcurie of 1311 per square centimetre of a large plane source. These sensitivity figures as observed for the131I plane source with a 19-hole collimator are given for each depth at the top of Fig. 15. They are found to be nearly independent of depth. For testing the performance of scintillation cameras, a line-source phantom has been developed in collaboration with the Czerny-Hospital in Heidelberg. The phantom consists of a thick Lucite plate with a pattern of parallel grooves, 1. 25, 2. 5 and 5 cm apart, in two perpendicular directions. A thin plastic tube, which can be filled with a radioactive solution, is threaded through the grooves. The phantom is positioned either close to the multichannel collimator of the scintillation camera at an angle with respect to the collimator face, or parallel to it at various distances. The effect of an absorbing medium between source and collimator can be determined by plac- ing the phantom in a tank of water. From a series of scintiphotos of the line-source phantom the following camera characteristics can be investigated:

(a) Uniformity of camera performance for the whole field of vision; (b) Spatial resolution of scintillation camera for gamma rays of various energies; (c) Depth response of scintillation camera for sources in air and in an absorbing medium (water); (d) Effect of operating conditions on camera performance.

1. 3. Whole-body counting

The investigation of whole-body counting techniques has been continued, with emphasis on generalization of insights previously obtained. This will permit a more economical design and a more effective use of whole-body counters, and should thus be of economic and scientific value to Member States contemplating the purchase or construction of this equipment. An important method for improving the accuracy of measurements on non-uniform or changing spatial distribution of a radionuclide is to make use of counts accumulated in the full pulse-height spectrum of the sodium iodide detector rather than just in the photoelectric peak of the spectrum. In many circumstances this procedure cannot be adopted, but it is particularly appropriate in clinical work where the identity of the radionuclide is known and its activity level usually high enough that interference from other radioactivity in the body is small. An example is shown in Fig. 17, which represents approximately the assay of the clinically important radionuclide 67 VIENNA AND SEIBERS DORF

131I. A point source was placed successively at different positions in a com- pressed wood phantom of the body, whose elliptical cross-section is shown. At each position a measurement was made of the 'body' in the usual way: an 8 in. diam. X4 in. Nal(Tl) crystal, 35 cm above the bed on which the phantom was lying, accumulated a spectrum while traversing from 1 head1 to 'feet1 . The number of counts recorded for-the several source positions were normalized so as to give unity at the centre of the phantom. The numbers on the left half of the ellipse apply to data recorded in the 0. 36-MeV photopeak, while those on the right pertain to the broad spectral energy range 0. 046 to 0. 44 MeV. It is clear that much less variation of the counting rate with position of source is observed when the broad energy range is used. A practical result of this is evident in Table XXVIII, which gives the variation of assay efficiency of 1311 in two people during the first 24 hours after an orally administered tracer dose. After a few minutes the isotope is mainly in the stomach, at 2 hours in the blood, and at 24 hours in the thyroid — a pattern of gross redistribution. The percentage discrepancy

3.2 1.56

г.и 1.51

i.eo 1.26

1.06 1.00 Ш 0.86

0.58 , ,0.66

0.66, 0.58

. 0.37 0.47

FIG. 17. Efficiency of assay of1311 point sources in phantom, normalized to unity at centre. Detector is scanned from 'head* to 'foot' above phantom during measurement. Left half: Results using photopeak of spectrum (0.36 MeV); Right half: Results using broad energy band of spectrum (0.046 - 0.44 MeV)

TABLE XXVIII. VARIATION OF ASSAY EFFICIENCY OF 131I IN PEOPLE DURING 24 HOURS AFTER ORAL ADMINISTRATION

Percentage discrepancy from first measurement

Time after Photopeak Broad band administration (0.36 MeV) (0.046 - 0.44 MeV) (h) Subject A Subject В Subject A Subject В

0.25 0 0 0 0

1.5-2.5 +10 +20 -6 0

24 + 2 +28 -7 -5 68 VIENNA AND SEIBERS DORF in the counts/min per retained /nCi is shown for each measurement relative to the first. Again the discrepancies associated with the broad energy band are smaller than those associated with the photopeak. Since sodium iodide crystals of many different sizes are used in whole- body counters throughout the world, it is of great interest to determine how crystal size affects the calibration. Phantom measurements similar to those described above have been performed for many radionuclides with sodium iodide crystals of four sizes: 8 in. diam. X4 in., 4 in. X4 in., 3 in. X3 in. (with well), 1 in. XI in. When the counting rates yielded in a specified spectral energy band are normalized to give unity for a point source at the centre of the phantom, the relative counting rates at other positions are nearly the same for all four crystals. This is illustrated for 137Cs (0. 66 MeV gamma rays) in Fig. 18a (photopeak) and Fig. 18b (energy band 0. 046 - 0. 74 MeV). The four numbers at each point pertain to the four respective crystals, as indicated in the figure. The comparatively small differences that do exist are almost eliminated when the body is measured first prone, then supine, and the average result computed. Calibration data, suitably normalized, are thus nearly independent of crystal size and shape.

Tl? 2.13 1.54 2.16 1.53 T44 166 1.70 Bhx4in linx lin j 44 1.32 1.68 1.73 \ 4 in x 4 in 3inx 3in 145 1.40 1.23 1.16 1.25 1.22 1.00 1.02 1.06 1 1.00 1.02 108 1 1.00 1.00 0.89 085 1 1.00 1.00 0.89 0.90 1 0.64 0.63 0.62 0.65 0.51 0.70 0.69 0 52 0.70 0.70 0.44 0.63 0.63 0.63 0.63 0.54 (1 .0.52 0.53 0.54

(a) (b)

FIG. 18. Efficiency of assay of 137Cs point sources in phantom, normalized to unity at centre, for crystals of four sizes. Four results at each point represent four crystal sizes as shown in inset. (a) Results using photopeak (0.66 MeV); (b) Results using broad energy band of spectrum (0.046 - 0.74 MeV)

In the measurement of 90Sr by whole-body counting two prominent issues are calibration (determination of counts/min per jiCi) and sensitivity in the presence of other radionuclides (e. g. 40 K,137Cs) in the body. By phantom measurements similar to those described above, it has been found that /90Sr -90Y bremsstrahlung (measured in the optimum energy range 0. 06 - 0. 15 MeV) is affected by overlying absorbers in very nearly the same way as is the 47Ca gamma radiation (measured in the photopeak). Since 47Ca is distributed throughout the skeleton in a pattern almost identical with that of 90Sr, people to whom tracer doses of 47Ca have been administered provide a very reliable calibration of 90Sr measurements. To investigate the problem of sensitivity, measurements have been performed on people and phan- 69 VIENNA AND SEIBERS DORF toms containing various relevant tracer isotopes. Finally, 11 persons pre- sumably containing only the normally observed radionuclides (40K, i37Cs) were measured for 80 minutes and the results were analysed in detail to determine the apparent 90Sr burdens. It was found that, at the lowest burdens, 90Sr can be determined with a standard deviation of 14 nCi, a value corresponding to less than 1% of the maximum permissible burden for occu- pationally exposed workers. The determination of the distribution of activity in the body by a profile scan generally requires a compromise between high spatial resolution and high assay efficiency. The influence of several collimator designs on this compromise have been investigated, and improved mathematical techniques for extracting the maximum information from the measurement are under development.

1.4. Statistics of radiation measurement

The statistical accuracy of radiation measurement is a very important issue in many fields including in particular medical radioisotope investigations where low activities are often dealt with. Two analyses of statistical questions were carried out, and the results were published.18

2. ACTIVITIES IN SUPPORT OF LABORATORIES IN MEMBER STATES

2. 1. Protein turnover studies

The Laboratory continues to prepare and distribute labelled proteins to institutions collaborating-in the Agency' s Co-ordinated Research Pro- gramme on the Use of Radioisotopes in the Study of Malnutrition in Tropical and Sub-tropical Regions. These labelled proteins are used by the recipients as reference materials to check the adequacy of their own locally made or commercially supplied preparations. Seven institutions participated in this project during 1966 and two distributions of 125I-labelled albumin and one of 125I-labelled gamma-globulin were made. Further distributions will take place during the forthcoming year. Abbreviated results from a typical distribution to four collaborating institutions are shown in Table XXIX. The albumin supplied by the Agency was labelled with125I, while all other preparations were labelled with 1311. The results submitted by Institutions A and В showed a similar metabolic behaviour for the Agency' s albumin and the local albumin when tested in the same subject. Three different preparations of 131I-albumin, obtained using different starting materials, were tested at Institution C. All of these showed increased catabolic rates and increased excretion of radioactivity in urine over the first 24 hours as compared with the Agency' s preparation, indi-

18 (1) DUDLEY, R.A., Statistically optimum radiation counting: a criticism of the Bradley-Marks background suppression system, Phys. Med. Biol. 11 (1966) 313. (2) DUDLEY, R. A., Statistically efficient use of reference pubes in spectrometer stabilization, Nuclear Instrum. Meth. 46 (1967) 116. -o TABLE XXIX. RESULTS FROM A TYPICAL DISTRIBUTION OF LABELLED PROTEINS о

Labelled albumin Date of PA Tip FCR EVM Institution Case start of Uo-24 mg/100 ml (d) Cft/d) IVM study Date (%) Source prepared

1 . 4.24 25.4.66 Agency 14.3.66 16.7 6.09 11.36 1.33 Local 11.4.66 13.0 10.06 12.38 1.28

• 2 4.10 25.4.66 Agency 14.3.66 14.0 5.94 12.47. 1.27 к< Local 11.4.66 12.3 9.32 12.62 1.13 Z >Z В 3 3.16 2.5.66 Agency 14.3.66 21.1 4.10 8.74 - > Local 29.4.66 21.1 4.42 8.54 z a 4 22.4.66 Agency 14.3.66 17.7 4.31 11.9 2.05 сл 1. 82 m a hH Local 21.4.66 15.1 3.81 14.0 2.05 СО m с 5 4. 85 22.4.66 Agency 14. 3. 66 14.1 2.87 7.3 1.78 jo Localb 21.4.66 14.1 3.83 13.4 1.71 СЛ a 6 3.78 22.4.66 Agency 14.3.66 29.1 4.66 6.7 1.82 о Localc 21. 4. 66 11.4 15.65 18.9 2.10 S

7 3.50 25.5.66 Agency 14. 3.66 22.0 3.73 4.3 0.64 Commercial - 15.9 8.99 6.9 0.66 D 8 3.42 25.5.66 Agency 14.3.66 14.4 5.74 4.7 0.72 Local 19.5.66 15.1 2.58 4.3 0.85

2 Starting material: Behringwerke albumin. Symbols: PA : Plasma Albumin concentration ^ starting material: acid-alcohol fractionated albumin. Tip: Half-disappearance time of plasma radioactivity c Starting materialt carboxymethyl cellulose column fractionated albumin. u0-24: Urine radioactivity over period 0-24 hours FCR : Fractional Catabolic Rate calculated from urine and plasma radioactivities EVM Ratio of Extravascular to Intravascular albumin Mass IVM ! calculated from urine and plasma radioactivities. 71 VIENNA AND SEIBERS DORF eating that they were significantly denatured and unsuitable for accurate turnover studies. This is especially noticeable with the preparation used in Case 6. Institution D tested a commercial product which also proved to be significantly denatured and a local preparation for which the results were in reasonable agreement with the Agency preparation except for a somewhat increased excretion of radioactivity in the urine over the first 24 hours.

2. 2. Support of whole-body counting activities in Member States

Training in whole-body counting techniques was provided for three physicists from Turkey, Egypt, and Austria, respectively. Continuing assistance was rendered to laboratories engaged in the study of persons with occupa- tional^ acquired burdens of 226Ra and 90 Sr. Provision was made for the routine screening for internal contamination of workers from the Seibersdorf Studiengesellschaft. To date only trace levels of contamination have been found in a few cases.

3. STUDY OF TOXICITY OF THOROTRAST IN VIENNA CASES

The investigation of Thorotrast cases in the Vienna area has been continued with financial support from the US Atomic Energy Commission. The dosimetric and epidemiological studies have proceeded along lines described in earlier reports with the collection of similar data on additional individuals in the Vienna population. In collaboration with scientists at the University of Vienna the recently initiated investigation of chromosome aberrations in peripheral blood lympho- cytes has been focused on a test of techniques and reproducibility of results. Five Thorotrast cases previously examined were selected for repeated studies. About six blood samples were taken from each at approximately monthly intervals. The cells from each sample were cultured for each of three different periods: 48, 72, and 96 hours. The frequency of various types of chromosome aberrations was then scored for each culture. Only tentative conclusions were reached in this as yet incomplete investigation. Chromosome aberrations were found in nearly every culture at a frequency exceeding that of normal persons, but the variability among different blood samples from the same person was considerable. The frequency of aberrations was not observed to vary dramatically with culture time. Since chromosome aberrations were found to be one of the most sensitive biological indicators of irradiation, the establishment of the most suitable conditions for observation, the degree of reproducibility to be expected, and the dose- effect correlation are all problems of great practical importance. VII. NUCLEAR ENERGY IN HYDROLOGY

The aim of the Hydrology programme in the Laboratory is to provide the technical backing for the overall Agency Programme of Water Resources Development, and to service the needs of Member States and the UNDP Spe- cial Fund Projects in providing the data needed in the application of isotope methods to water resource development.

1. TRITIUM

The use of environmental tritium data in studying water balance and groundwater resources showed a further increase and therefore resulted in an increased demand for analyses. The concentration of tritium in groundwater is usually so low that enrichment and gas counting are required. The capacity of the tritium laboratory was enlarged to allow the analyses of about 140 samples per month: probably the greatest throughput of any laboratory in the world.

1.1. Enrichment by electrolysis

The routine procedure of enrichment is essentially unchanged. The number of enriched samples was increased by running the 16 cells continuously. The second set of 8 cells was prepared for carrying on experiments concerning the influence of the temperature distribution in the re- frigerator on the reproducibility of tritium recovery. A number of experiments were performed to detect a possible isotope fractionation effect during the distillation procedure before and after electrolysis. Within a 3% experimental error, no isotope effect was observed.

1.2. Enrichment by gas chromatography

In the Third Laboratory Report19, a recovery of 100% tritium from a 20-litre hydrogen sample in a final volume of 3. 3 litres was reported. This concentration factor is sufficient in that the counters available have just this volume. To make the method useful in cases where smaller counters are used, a second retention column was attached to the line. This was made of copper tubing 3 mm i. d. and 2.3 m long, filled with Linde molecular sieve 5A and had a hydrogen capacity of 0. 5 litre. In operation, the enriched hydrogen in the first retention column was also eluted with helium using the temperature displacement technique. The tritium recovery in the second retention column was 100% giving an overall enrichment factor of 40. Stan-

"iNTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No. 55, IAEA, Vienna (1966).

72 73 VIENNA AND SEIBERS DORF dard 1000 tritium unit (T. U. )20 samples were processed in this way and the results agreed with the known value to within + 2%. Further investigation of possible 'memory effects' in the apparatus showed that less than 0. 1% of the tritium from one sample contaminates the next sample processed. In most previous experiments the flow rate of the eluting gas, helium, was 350 ml/min. This figure was arrived at pairtly theoretically and partly as a compromise between the speeds of flow for two columns of widely differing diameters. Another important factor, however, is that the separation is also influenced by the speed of withdrawal of the primary column from the liquid nitrogen bath in the temperature-displacement technique used. Earlier experiments showed that decreasing the warm-up time too much caused poorer separation due to the effects of the heat of adsorption if the sample desorbed too quickly. To obtain à clearer picture of the effects of flow rate and heat of absorption, the effects of flow rate of helium on the separation of tritium and hydrogen was followed using only small samples of HT-H2 mixtures (16 ml). The best separations were obtained at a flow rate of 150 ml/min and these were appreciably better than at 350 ml/min. When these conditions were used on 20-litre samples, when the heat of adsorption evolved is large and the column is heavily loaded, the advantage in separation was small as is shown in Table XXX.

TABLE XXX. TRITIUM RECOVERY FOR DIFFERENT FLOW RATES OF HELIUM (20-litre sample)

Helium flow rate Tritium recovery (ml/min)

350 97.2 97.0

150 98.4 98.6

In these experiments the retention column used was deliberately made too short to retain all the tritium to make the observation of effects of flow rate easier. The lower flow rate conditions will be used in future because it is more economical in use of helium and the pressure increase in the apparatus is smaller. The development part of this programme is completed and efforts are now concentrated on establishing design parameters for a compact, semi- automatic apparatus for routine use.

1. 3. Gas counting

Gas sample preparation. The gas preparation line was modified and 8 samples can be prepared per day by one person.

201 t.u. = ~ x10-18. 74 VIENNA AND SEIBERS DORF

Palladium on asbestos is now being used for preparation of ethane. No poisoning effects are observed when using palladium on asbestos, so one loading of catalyst lasts for the preparation of many samples.

Proportioned counters. A new gas counter, manufactured by W. H. Johnston Laboratories, Inc., Baltimore, was installed. The counter is similar to another installed earlier. Thebackground ofthenew counter is 1.2 counts/min and the efficiency corresponds to 50 T. U. per counts/min.

1. 4. Liquid scintillation counting

The polyethylene counting vials were re-examined and it was found that if visual selection of vials is performed before use, good reproducibility of counting in individual vials can be obtained. Polyethylene vials are superior to quartz vials in terms of lower background and higher counting efficiency. The polyethylene vials are now in routine use; the background is 8 counts/min and the efficiency is 250 T. U. per counts/min for the dioxane-naphthalene- water system. A study of the possibility of using TRITON-X as an agent for emulsifying water samples in toluene scintillator has been initiated. Preliminary experiments showed a better counting efficiency for the TRITON-X method than for the dioxane-naphthalene system. Further experiments are needed to establish the routine procedure for preparation and counting of samples.

1. 5. Sampling of air humidity for tritium measurement

The monitoring of tritium concentration in the moisture of the air in the laboratory has been shown to be a good check for possible local tritium contamination in the laboratory originating from highly active water samples. Two methods of sampling air moisture were developed. In the first system a battery-operated fan flows the air through a cold trap kept at a low temperature (about -60° C). About 6 ml of water is collected in the trap during 10-20 minutes depending on the moisture content of the air. In the second method a set of 4 aluminium plates is partly immersed in a Dewar flask filled with liquid nitrogen. About 15 - 30 minutes are required for freezing the air moisture as snow on the surface of the plates, resulting in about 6 ml of water. The air moisture samples can be counted directly in a scintillation counter to show whether or not the atmosphere in a particular room of the laboratory is accidentally contaminated by hot samples.

2. CARBON-14

The routine procedure for determination of 14C in water was established and about 4 samples per week can be measured.

2. 1. Extraction of carbonates from water The precipitation procedure, as described in the previous report, is being carried out in the field; the precipitate containing 2-4 g of carbon is 75 VIENNA AND SEIBERS DORF sent to the laboratory. C02 envolved from the precipitate is synthetized into methane gas. When the CO2 volume obtained is less than the 6 litres necessary for filling the counter to 140 cmHg, the sample is diluted with dead C02 (originating from marble) and a correction factor is applied to the measurement. Experiments with an ion-exchange method of sampling carbonates in water have also been initiated in order to compare this method with the precipitation procedure in terms of simplicity and efficiency.

2. 2. Proportional counter

A new proportional counter was set up for i4C counting. The main counter, manufactured by Johnston Laboratories, Inc. works, in an anti- coincidence circuit with an Agency-constructed ring counter is placed in a 10-cm-thick lead shield. The counters are connected to an electronics console (Philips). The background in the 14C energy channel-measured for 140 cmHg filling of methane prepared from marble is 9.1 counts/min. The NBS standard oxalic acid gives 20. 7 counts/min net count rate. The samples are counted for about 24 hours to obtain about 1% statistical accuracy. VIH. NUCLEAR ELECTRONICS SERVICE AND DEVELOPMENT

The Electronics Section designs and develops measurement and control equipment specially suited to the needs of the Agency1 s Laboratory and which is not available commercially. The Section also maintains and services electronic equipment in the laboratory. In addition to smaller items like fast discriminators, low-voltage and high-voltage power supplies, a control circuit for an X-ray fluorescence apparatus, a control circuit for an automatic pipette, preamplifiers for scintillation counters etc., and the following major apparatus was developed.

1. RANDOM COINCIDENCE SIMULATOR

1.1. Principle of operation

This instrument simulates a statistical time distribution of pulses of which the mean count rate is known with an accuracy of one part in ten million. It serves for the accurate determination of the resolution time of semi- fast coincidence circuits as well as the dead time of counting channels, provided these can be defined by a rectangular pulse. 21 It can also be used for the determination of differential linearity of time-to-pulse-height converters. (Fig. 19(a) and (b)). The operation of this instrument is explained on the basis of the pulse diagram (Fig. 20). The apparatus supplies two pulse trains of constant frequencies fj and f2 which differ very little from each other. It is assumed that at a certain time instant t0 there is a pulse both in channel fx and in channel f2. If f2 is larger than f-,, the first pulse following t0 will be delivered in f2 earlier than in fA. The time interval between the two pulses will be Д = 1/fj - l/f2. The time intervals between the respective second pulses following t0 will then be 2 Д and so on, until after a time to + tg the pulses of both channels will coincide again. Then this process is repeated. Figure 20 shows that during the cyclus time tB in the mixed pulse train any pulse spacing down to the smallest interval Д may occur. 22

21 This is the case when dead-time effects resulting from a coincidence of three or more pukes in the dead-time interval can be neglected.

22WELLS, F.H., AERE, Harwell, unpublished work.

76 77 VIENNA AND SEIBERS DORF

(a)

(d)

(o)

(b)

FIG. 19. Random coincidence simulator (a) Block diagram (b) Board of scaler and pulse former 2 (c) Main instrument with open thermostat and pulse former 3 behind (d) Case and power supply 78 VIENNA AND SEIBERS DORF

- T1 J

Д 2A ЗД 4Д 5Д 6Д 7Д 8Д 9Д 10 Д

t„'tB

FIG. 20. Pulse diagram of the random coincidence simulator

1. 2. Coincidence resolution and dead-time measurement

If both channels are fed into a coincidence instrument, the coincidence count rate С is in the extreme case A— 0

С=2тс^г (1)

where тс is the resolution of the coincidence instrument. This is in accordance with the formula for statistical count rates. When

r, - £ (2) then Cj, the number of pulses per second of type f-, falling into the coincidence range rclfollowing a pulse of type f2) is(Tc/T2)f1, and C2> the number of pulses per second of type falling into the coincidence range тс following a pulse of type f1( is (тс /тг) f2. Then

which together with Eq. (2) gives Eq. (1). If the mixed pulse train is fed into a counting channel, with Eq. (1) the following dead time в is obtained

e = V/f2 - A (3) ¿ V2 where A is the measured count rate. This is also in accordance with the dead-time formula for purely statistical pulse trains. 79 VIENNA AND SEIBERS DORF

1. 3. Counting error

The counting error of rc and в (Formulas (1) and (3)) consists of a maximum systematic error which is defined by the smallest resolvable time interval

and a statistical counting error which is caused as follows: The count rate С given in Eq. (1) is not continuous but consists of several individual bursts. Pulses are obtained from the coincidence instrument only when the pulse spacing between pulses from channels fx and f2 does not exceed 2 тс . When spacing is larger, the coincidence instrument does not deliver any pulses. Therefore, when the counting of the coincidence count rate С commences during such an interval and ends during another, this is not reflected in the result. The number of coincidences remains unchanged irrespective of the variation of ± 1 interval of the measuring time. This means that the mean count rate С which is calculated from the measuring time includes an error to the extent of a variation of + 1 interval in the measuring time. This statistical error (Fa ) in measuring the coincidence resolution is then

Fst =±T(f2-f1) (5) where T is the total measuring time. These considerations apply also to the dead-time determination. A further source of error is the counting time itself. This should particularly be taken into account in the case of dead-time measurements, since differences of figures which differ very little from each other are involved and thus a small deviation of С has a considerable bearing on the result.

1. 4. Measurement of differential linearity of time-to-pulse-height converters

When the pulses of one channel are used as start signals and those of the other as stop signals for a time-to-pulse-height converter, a multichannel analyser connected to this instrument will give an equal number of pulses in each of its channels for a linear TPC.

The error. In this case the variation in pulse spacing is directly reflected in the error (5 XlO-з for our instrument).

2. DETAILED DISCUSSION OF THE INSTRUMENT

The operation as well as the characteristics will be explained with the aid of the block diagram (Fig. 19(a)). Two quartz generators (basic frequency fj = 100 kHz) are placed in an electronically controlled thermostat. To enable an optimal choice of 80 VIENNA AND SEIBERSDORF measuring error and measuring time the frequency of i-¿ is adjustable in steps. (This gives the possibility of choosing the time interval and cyclus frequency. ) f2 - fj can be set at 3, 10 or 30 cycles. The two sine waves from fa and f2 are mixed in a HF mixer and thus the interference frequency f2 - fj is obtained which acts on a pulse former 1, which then supplies a pulse train with a PRF of f2 - f j. With the aid of this frequency the frequency of f2 can easily be adjusted and the statistical error (Eq. (5)) can be calculated. Pulse formers 21 and 22 transform the sine waves type fj and f2 into pulse trains of corresponding frequency. To obtain frequencies smaller than the basic frequency the binary scalers 1 and 2 are employed. In this connection the following should be borne in mind. When the scaled frequencies f¡/S (S = scaling factor) are introduced into Eq. (4), the minimum interval Д becomes larger and is trans- formed into SA. At the same time the interference frequency fB decreases to ffi /S. This has to be taken into account in the error calculation. Pulse formers 3^ and 32 produce suitable output pulses as follows:

Output pulse form into 50 П load

la_and 2aPositive rectangle, height 9 V, width 0. 5 /js; Rise time 25 ns _lb_and_2bj_ Negative needle pulses, height 320 mV; Rise time 10 ns; Fall time 20 ns Output_ijripedancej 50 Q

To mix the two pulse trains the non-linear mixer n for the rectangle pulses and the linear mixer 1 for the needle pulses are used. They have an output impedance of 50 fi and their output pulse amplitudes are:

la_and 2aj_ 8.5 V lb_and_ 2_bj_ 80 mV

Numerical value of systematic error (Eq. (4)) for

f2 - fj = 3 Hz is 0. 3 ns times scaling factor f2 - fj = 10 Hz is 1. 0 ns times scaling factor f2 - fj = 30 Hz is 3. 0 ns times scaling factor

Statistical error depends on measuring time (Eq. (5)) and scaling factor as mentioned above. Errors of higher order which result from instabilities of quartz generators or from the fact that fi /(f2 - fi) does not give an integer'23 are negligible.

23 Compare the Lissajous figure for frequencies differing very little from each other. s

EX. ADMINISTRATIVE MATTERS, STAFF MEMBERS AND PUBLICATIONS

1. TRAINING

During the period under review 20 young scientists from 14 different countries received training at the laboratory, for a total number of 127. 5 man-months. 3 Fellows (Navaratna, Ceylon; Li, China; Khambanonda, Thailand) worked with the Plant Breeding and Genetics group; 2 Fellows (Lumpaopong, Thailand; Aleksic, Yugoslavia) with the Soils, Irrigation and Crop Produc- tion group; 3 Fellows (Wickramasinghe, Ceylon; Ravelojaona, Madagascar; Ramos, Peru) with the insect eradication and pest control group; 4 Fellows (Boonkong and Atisook, Thailand; Silva, Chile; Gunay, Turkey) with the Section of radioisotope applications in hydrology; 4 Fellows (Radak, Yugos- lavia; Tenreyro, Argentina; Nguyen Nhiep and Cao Thu Hien, Vietnam) were trained in the field of radionuclide standardization and radiation dosimetry; 1 Fellow (Costa-Alonso, Mexico) in the field of industrial application of radioisotopes; 1 Fellow (El-Asaly, UAR) in the field of whole-body counting; 1 Fellow (Mrs. Kovács, Hungary) assisted in the food irradiation project; 1 Fellow (Mrs. Czosnowska, Poland) was involved in an investigation of the behaviour of strongly basic anion-exchange resins towards alkaline earth ions (Environmental Radioactivity Group). A paper describing the interesting results of this piece of research will be published.

2. . LABORATORY EQUIPMENT DONATED BY GOVERNMENTS OF MEMBER STATES

(a) The French Government donated radioisotope instruments, electronic equipment for coincidence counting and a 2-Ci cobalt source at a total value of about US $49 000. (b) A mass-spectrometer, complete with power supply, analyser, sample inlet system, electronic two-pen recorder, tools, and all parts and accessories was donated by the Japanese Government, total value of about $30 000. (c) Eighteen pieces of laboratory equipment at a value of about $10 000 and a Volvo Stationwagon at a value of about $3000 were donated by the Swedish Government; (d) The Government of Israel donated a radiation analyser (Môssbauer effect spectrometer) at a value of about $4000; (e) A gas proportional counter and an anti-coincidence counter at a value of $2035 were donated by the United States Government;

81 82 VIENNA AND SEIBERS DORF

(f) Micro-analysis attachment as part of a previous donation of a complete X-ray system was donated by the Government of the Federal Republic of Germany, a total value of $ 1740.

3. FINANCE.

The budget

For the financial year 1 January to 31 December 1966, the Laboratory had at its disposal funds totalling US $856 691. Of this sum, $579 854 were drawn from the Agency" s regular budget, $ 146 000 transferred from the General Fund (voluntary contributions), and $ 130 837 represented direct income to the Laboratory from sales of radioactive standards and services rendered to Member States and savings on previous years. The income to the Laboratory includes $27 260 for the distribution of radioactive standards, $ 11 705 re-imbursable research work for the United States Atomic Energy Commission and $28 470 for miscellaneous services rendered.

Expenditure

Total charges in 1966 can be summarized as follows:

US $

Salaries and other staff costs 572 400 Duty travel of staff 1 500 Scientific equipment 67 000 Scientific and technical supplies 56 800 Contractual technical services 3 500 General services and non-technical supplies 79 800

TOTAL 781 000

A summary of the total cost of the various programmes of work of the Laboratories at Vienna and Seibersdorf during 1966, including depreciation charges for the usage of capitalized equipment, is given below. The total cost exceeds the actual expenditure of $781 000 by $53 300. This difference is due to amortization cost of previously acquired scientific equipment, which is higher than the amount spent for the acquisition of new equipment and also due to unliquidated obligations, not included under Expenditure, for the con- sumption of utilities during the later part of 1966. 83 VIENNA AND SEIBERS DORF

(A) Standardization of measurement and analytical methods related to nuclear energy applications US $ 1. Calibration of radionuclides Development of calibration methods and of techniques associated with calibration 75 200 Determination of constants relevant to standardization 8 300 Distribution of radioactive standards 35 200 Neutron fluence measurements 26 100 Tritium assay (for Safeguards programme) 15 000 2. Radiation dosimetry 28 000 3. Reference materials Analysed uranium ores and analysed samples of uranium oxide containing trace impurities 36 400 4. Analytical quality control 76 100 5. Trace element analysis 15 100

(B) Analytical services to Member States 18 600

(C) Chemical and physico-chemical investigation relevant to the Agency1 s programme 1. Analytical chemistry in the Safeguards programme 26 200 2. Analytical chemistry in the Life Sciences programme 14 700 3. Studies on decomposition under radiation sterilization 15 600 4. Purity of commercial radiochemical preparations 19 900

(D) Nuclear energy applied to agriculture

1. Soil fertility, irrigation and crop production 99 400 2. Entomology (Mediterranean fruit fly, olive fly, tsetse fly) 38 900 3. Genetics and plant breeding (research on mutation induction and mutagen service treatments) 31 100 4. Food irradiation 11 600

(E) Nuclear energy in medicine

1. Development of techniques and instrumentation 47 900

2. Study of toxicity of Thorotrast in Vienna cases 31 200

(F) Nuclear energy in hydrology

1. Improvement of methods for isotope application 12 600 2. Determination of isotopic composition of natural water 21 500 84 VIENNA AND SEIBERSDORF

3. Surface and groundwater investigation 10 100 4. Services to Member States 21 300 5. Participation in the UN International Hydrological

Decade 17 200

(G) Instrumental servicing and development

1. Nuclear electronics maintenance and development of commercially unobtainable electronic equipment 27 000 2. Mechanical workshop services and constructions 20 900

(H) Training of Fellows from Member States 33 200

GRAND TOTAL 834 300

4. PROFESSIONAL STAFF OF THE LABORATORY

The staff of the Agency1 s Laboratories are under the supervision of the Division of Research and Laboratories, Department of Research and Isotopes. In 1966, the professional staff members were:

HARBOTTLE, Garman * (United States of America)

Born 1923; B.S. California Institute of Technology; Ph.D. Columbia University.

АЕС Fellow (1951-1952), Guggenheim Fellow (1957-1958), Brookhaven National Laboratory, 1949-1965. Joined the IAEA in September 1965.

Director, Division of Research and Laboratories.

SANIE LE VICI, Alexandre* (Romania)

Born 1899; University of Bucharest, University of J assy, Paris University (Sorbonne) ; M.Sc., D.Sc. (physics). Member of the Academy of the Romanian People's Republic.

1931-1940 Research Associate, Institut du Radium, Paris; 1945- Professor of Nuclear Physics (Radio- activity), University of Bucharest; 1950- Head, Department of Nuclear Spectroscopy, Institute of Atomic Physics, Bucharest. Joined the IAEA in May 1958.

Deputy Director, Division of Research and Laboratories.

COOK, Gerald B. (United Kingdom)

Born 1921; University of Birmingham, University of Cambridge; B. Sc., Ph.D. (chemistry).

•f Working within the Scientific Secretariat of the Agency and charged with certain supervisory functions for the Laboratories. 85 VIENNA AND SEIBERSDORF

1944-1947 Member, Joint Canadian-British Atomic Energy Project Montreal, Quebec and Chalk River, Ontario, Canada; 1947-1953 Chemistry Division, AERE, Harwell, UK; 1954-1960 Head, Chemistry Group, Isotope Division, AERE, Harwell, Joined the IAEA in 1960.

Head, Chemistry Section; in charge of the Seibersdorf Laboratory.

BEN H AIM, Aharon (Israel)

Born 1932; Technische Hochschule, Vienna; Diplom-Ingenieur (physics); Dr. techn. sc. (physics).

1959-1960 Staff member "Technion", Israel Institute of Technology (Haifa, Israel). Joined the IAEA in February 1962.

Physicist responsible for the operation of the whole-body counter, working mainly on gamma ray spectroscopy and its applications to the dosimetry of Thorotrast.

BERGERHOFF, Giinter A. (Federal Republic of Germany)

Born 1926; Dipl. Chem., Dr. rer. nat., University of Bonn, Germany.

1952-1964: Privat-Dozent, University of Bonn. Joined the IAEA in 1965.

Inorganic chemist responsibly for the preparation of standards of low-level radioactivity and the organization of the intercomparison scheme for these samples, until 27 April 1966.

BROESHART, Hans (The Netherlands)

Born 1924, Amsterdam; Agriculture University Waageningen; Dipl. Eng. and Ph.D. (agriculture).

1948-1950 Assistant, Laboratory of Soils and Fertilizers, Waageningen; 1950-1958, Head, Soil Science Section, Research Department of Unilever Plantations, Congo; 1958-1960 Principal Research Officer, Laboratory of Soils and Fertilizers, Waageningen. Joined the IAEA in 1961.

Head of the Laboratory Section of the Agriculture Division.

CAMERON, John F.* (United Kingdom)

Born 1929; Glasgow University; B.Sc.

1950-1962 U.K.A.E.A. Harwell; 1951-1952 Health Physics Division; 1952-1962 Isotope Division. Joined the IAEA in 1962.

Physicist responsible for the industrial applications of isotopes.

DINÇER, Turgut Mustafa* (Turkey)

Born 1923; Technical University of Istanbul; M. Sc., Cir. Eng.

•f Working within the Scientific Secretariat of the Agency and charged with certain supervisory functions for the Laboratories. 86 VIENNA AND SEIBERSDORF

1962-1965 Assistant Professor, Middle East Technical University, Ankara, Turkey. Joined the IAEA in March 1965.

Physicist responsible for all surface water studies, including field experiments on stream discharge measurements and also sediment transport.

DUDLEY, Robert A. * (United States of America)

Born 1926; Pennsylvania University, Massachussets Institute of Technology; B. A., Ph.D. (physics).

1951-1953 Fulbright Scholar, Medical Research Council, Hammersmith Hospital, UK; 1953-1955 Staff member. Division of Biology and Medicine, USAEC; 1955-1956 Consultant to the Egyptian AEC; 1956-1960 Research Associate, Department of Physics, MIT. Joined the IAEA in 1960.

Physicist responsible for the whole-body counter and associated activities.

FERRARIS, Marco M. (Italy)

Born 1931; Turin University; D. Sc.

1961-1964 Staff member, Italian National Atomic Energy Board. Joined the IAEA in September 1964.

Physico-chemist, in charge of the X-ray fluorescence measurements, until 29 September 1966.

FLORKOWSKI, Tadeusz (Poland)

Born 1929; Academy of Mining and Metallurgy, Institute of Nuclear Physics, Cracow; Ph.D.

1950-1964 Staff member. Institute of Nuclear Physics, Cracow. Joined the IAEA in September 1964.

Working on electrolytical enrichment of tritium in water samples and tritium counting in the low-background gas counter.

FRIED, Maurice* (United States of America)

Born 1920; Cornell University, Purdue University; B.Sc., M.Sc., Ph.D. (agriculture, soil chemistry).

1947-1948 Instructor in Agronomy, Purdue University; 1948-1960 Research Soil Scientist, US Depart- ment of Agriculture, Agricultural Research Service, Beltsville, Md; 1955-1960 Teacher US Department of Agriculture, Graduate School. Joined the IAEA in 1960.

Director, Joint FAO/IAEA Division of Atomic Energy in Agriculture.

GALATZEANU, loan (Romania)

Bom 1925; Moscow University; Ph.D. (chemistry).

1957-1964 Staff member. Institute of Atomic Physics, Bucharest. Joined the IAEA in February 1964.

Radiochemist, responsible for investigating methods of analysis of commercial radioisotopes and labelled compounds.

•f Working within the Scientific Secretariat of the Agency and charged with certain supervisory functions for the Laboratories. 87 VIENNA AND SEIBERS DORF

HOUTERMANS, Hans (Federal Republic of Germany)

Born 1919; University of G

1951-1958 Staff member, Isotopenlaboratorium, Gâttingen; 1959-1960 Staff member, Max-Planck Institute for Physics, Munich. Joined the IAEA in 1960.

Head, Physics Section.

HORTON, Charles A. (United states of America)

Born 1918; Cornell University, N. Y., University of Michigan, M.S., Ph.D. (chemistry).

1942-1944 Staff member Bell Aircraft Corp. ; 1945-1949 Research assistant. University of Michigan; 1949- Research chemist, Union Carbide Corp. Joined the IAEA in November 1966.

Analytical chemist responsible for analytical activities of the chemistry programme.

KEROE, Erich A. (Austria)

Born 1926; Vienna University; D.Phil, (physics).

1950-1955 Collaborator in the Physical Institute (Electronics) Vienna University; 1955-1958 Consultant to several firms manufacturing nuclear electronic equipment. Joined the IAEA in 1958.

Head, Electronics Section.

KOSTA, Lado (Yugoslavia)

Born 1921; Ljubljana University; Dipl. Eng., Ph.D. (chemistry).

1945-1952 Head, Toxicological Laboratory, Institute for Legal Medicine, Ljubljana; 1952-1963 Senior Scientific Officer; Head, Analytical Section, J. Stefan Nuclear Institute, Ljubljana; 1955-1962 Lec- turer, analytical chemistry; 1962-1963 Professor, University of Ljubljana. Joined the IAEA in 1963.

Analytical chemist responsible for analytical activities of the chemistry programme.

KOEHLER, Wilfried (Federal Republic of Germany)

Born 1932; University of Munich, Germany; Dipl.Phys., Dr.rer.nat.

1958-1966 Staff member. Research Reactor Station of Technische Hochschule Muenchen. Joined the IAEA in 1966.

Responsible for neutron flux density measurements.

LEE, Byung Hun (Korea)

Born 1929; College of Technology, Seoul: Leicester College of Technology, England; B. Sc. .Post- graduate diploma. 88 VIENNA AND SEIBERS DORF

1955-1959 Instructor at Dongdok Women's College, Seoul; 1959- Staff member Korean Atomic Energy Research Institute. Joined the IAEA in September 1966,

Working in collaboration with the Hydrology Section on gamma-active tracers for water.

LEICHNAM, Jean-Pierre (France)

Born 1928; University of Bordeaux ; D. Sc. (physico-chemistry).

1954-1959 University of Bordeaux (Engineer); 1959- Staff member, CEA, Saclay. Joined the IAEA in 1965.

Working on chemical spectroscopy until 2 September 1966.

MAUNOWSKI, Jerzy, T. (Poland)

Born 1923; Technical University Lvov; Technical University Gdansk; Institute of Nuclear Research, Warsaw; M. Sc. (chemistry), D.Sc. (math.-phys. sciences).

1956-1960 Chief, General Analytical Laboratory, Institute Badan Jadrowych, Warsaw; 1960- Chief, Radiometric Laboratory, Institute Badan Jadrowych, Warsaw. Joined the IAEA in 1965.

Responsible for analysis of reactor fuels for safeguards interest.

MERTEN, Dietrich (Federal Republic of Germany)

Born 1920; University of Bonn; D.Sc. (chemistry).

1953-1959 Head, Isotope Laboratory of the Research Centre on dairy products, Kiel; 1959-1960 IAEA scientific consultant. Joined the IAEA in 1961,

Inorganic chemist, responsible for the low-level radioactivity (LOWRA) programme and related intercomparisons.

MIDDELBOE, Victor (Denmark)

Born 1920; Royal Veterinary and Agricultural College, Copenhagen, University of Copenhagen; Agronom, Lic. agro., Mag.sc. (physics).

1943-1944 Staff member, Farmer's Society, Odsherred; 1954-1956 Teaching and research. Royal Ve- terinary and Agricultural College, Copenhagen; 1956-1966 Lecturer, in charge of isotope laboratory. Royal Veterinary and Agricultural College, Copenhagen. Joined the IAEA in April 1966.

Concerned with plant nutrient supply programme and the development of improved techniques for 15N determination.

MIGUEL, Manuel (France)

Born 1929; Ecole Centrale d'Electronique, Conservatoire National des Arts et Métiers, Paris. VIENNA AND SEIBERSDORF 89

1955-1960 Technical Assistant, CEA, Paris, and CEN, Fontenay-aux-Roses and Saclay. Joined the IAEA in 1960.

Physicist responsible for investigations into new counting methods and techniques.

MIKAELSEN, Knut M. (Norway)

Born 1920; Oslo University; M. Sc. (chemistry), Ph.D. (genetics).

1950-1951 Postgraduate Fellow, Cornell University, USA; 1951-1953 Research Fellow, Brookhaven National Laboratory, USA; 1953-1959 Senior Research Associate, The Agricultural College, Vollebekk (Norway); 1959-Assistant Professor, University of Bergen (Norway), Joined the IAEA in 1965.

Responsible for plant breeding and genetic programme.

MONRO, John M. (Australia)

Born 1927; University of Adelaide; Ph.D.

1958-1963 Staff member. University of Adelaide, S. Australia. Joined the IAEA in April 1964.

Entomologist engaged in the rearing of the Mediterranean fruit fly, in connection with the application of the sterile-male technique for insect population control and eradication.

MUELLNER, Theodora H. (Austria)

Born 1926; University of Vienna; M.D.

1955-1962 Medical Staff, Allgemeines Krankenhaus, Vienna. Joined the IAEA in June 1962.

Engaged in the Thorotrast research project, Medical Physics Section.

NAGL, Hans (Austria)

Born 1928; Technische Hochschule, Vienna; Dipl. Eng., Dr. Techn. Sciences.

1955-1960 Assistant, Institute of Experimental Physics, Technische Hochschule, Vienna; 1960-1961 Teacher (physics and mathematics) Bundesgewerbeschule, Vienna). Joined the IAEA in 1961.

Physicist responsible for the development of calorimetric and other methods of radiation dosimetry.

NETHSINGHE, Douglas (Ceylon)

Born 1928; University of Ceylon; B.Sc. (chemistry), Ph.D. (soil chemistry).

1951-1952 Research Assistant, Industrial Research Laboratories; 1952-1959 Research Assistant, Coconut Research Institute; 1959-1966 Soil chemist, Coconut Research Institute. Joined the IAEA in October 1966.

Responsible for tree crop fertilization programme. 90 VIENNA AND SEIBERSDORF

PAYNE, Bryan R. * (United Kingdom)

Born 1927 ; University of Nottingham ; B. Sc., A. R.I. C.

1950-1958 Senior Scientific Officer, Isotope Division, U. K.A.E.A., AERE, Harwell. Joined the IAEA in 1958.

Head, Hydrology Section.

PARR, Robert Middleton * (United Kingdom)

Born 1938; University of Cambridge; University of London (Institute for Cancer Research); B. A., M.A. (physics, chemistry), Ph.D. (biophysics).

1962-1964 Resident Research Associate, Argonne National Laboratory, USA. Joined the IAEA in January 1965.

Physicist responsible for the development of activation analysis techniques and their application to biological and medical problems.

PETEL, Maurice (France)

Born 1928; Conservatoire National des Arts et Métiers, Paris; Dipl. Etudes Supérieures Techniques.

1949-1955 Research Assistant, Association des ouvriers en instruments de précision, Paris; 1955-1959 Physicist, CEN, Saclay; 1959-1961 Physicist, CERAM, France. Joined the IAEA in 1962.

Responsible for the development of new calibration methods for radionuclides until 15 October 1966.

ROSENBERG, Henry E. (United States of America)

Born 1931; Clark University, USA; Ph.D. (chemistry).

1960-1964 Staff member, Yale University, USA. Joined the IAEA in July 1964.

Inorganic and radiochemist investigating inorganic stable compounds containing gamma-emitting radioisotopes to be used as tracers for water, until July 1966.

SUSCHNY, Otto (Austria)

Born 1924; Vienna University; D. Phil, (chemistry).

1954-1958 Research Assistant, Radiochemical Department, Vienna University. Joined the IAEA in 1958.

Head, Low-Level Radioactivity Group.

•f Working within the Scientific Secretariat of the Agency and charged with certain supervisory functions for the Laboratories. 91 VIENNA AND SEIBERSDORF

TENSHO, Kiyoshi (Japan)

Born 1926; University of Tokyo; B. Sc.

1961-1964 Staff member, Japan Atomic Energy Research Institute, Tokyo. Joined the IAEA in April 1964.

Soil chemist, working on the uptake of trace minerals by the rice-plant in connection with the Agencyfs co-ordinated rice research programme until 31 March 1966.

THATCHER, Leland L. * (United States of America)

Born 1923; George Washington University, USA; Ph.D.

196' -1963 Staff member, US Atomic Energy Commission. Joined the IAEA in January 1964,

Engaged in work on methods for the enrichment of tritium in water samples and in the study of the use of 14C for dating groundwater, until 2 July 1966.

VAS, Károly* (Hungary)

Born 1919; Technical University, Budapest; Dipl. Chem. Eng., Ph. D., D.Sc., Con. Member of the Hungarian Academy of Sciences.

1941-1944 University Assistant, Technical University, Budapest; 1944-1959 Head of Microbiology Section, Central Food Research Institute, Budapest; 1959- University Professor, Institute of Food Tech- nology and Microbiology, College of Horticulture and Viticulture, Budapest. Joined the IAEA in 1964.

Responsible for the laboratory programme in food irradiation until 13 September 1966.

VASILYEV, Vadim (USSR)

Born 1920; University of Moscow; Diploma (physics).

1950-1953 Junior Scientific Collaborator, Institute of Physical Problems, Moscow; 1953-1966 Head of mass spectrometry group, Institute of Physical Chemistry, Moscow, Joined the IAEA 20 June 1966.

Physicist responsible for the operation and maintenance of the mass-spectrometer and the interpretation of results.

VETTER, Herbert * (Austria)

Born 1920; Vienna University; M.D.

1951 British Council Fellow; Post-graduate Medical School (London); 1954 Research Fellow, Sloane Kettering Institute for Cancer Research, New York, USA; Assistant Professor, Vienna University. Joined the IAEA in 1958.

Assistant Director, Division of Isotopes, Head, Medical Physics Section.

•f Working within the Scientific Secretariat of the Agency and charged with certain supervisory functions for the Laboratories. 92 VIENNA AND SEIBERS DORF

VUORINEN, Antti Pauli V. (Finland)

Born 1932; Institute of Technology, Helsinki; M.Sc.

1961-1964 Staff member. Institute of Technology, Otaniemi, Finland. Joined the IAEA in October 1964.

Physicist, engaged in work on standardization of neutron flux measurements, until 3 October 1966.

ACKNOWLEDGEMENTS

The technicians of the Mechanical Workshop, headedbyMr. H. Figdor, were, as in the past years, of great help to the scientific staff of the Labora- tory with their skill, competence and co-operativeness in developing and constructing a considerable number of special devices and apparatus required for the implementation of research projects and commercially not available. Among these, the following deserve to be mentioned:

Scanner for slow movement of 30-cm-long radioactive line source for the investigation of focusing collimators. Automatic scanning system for X-ray fluorescence measurements. Large spherical 4тг proportional counter, 16-cm diam. for X-ray counting. 2ж proportional counter for radioactive liquids. Scanner for thin-layer chromatograms. Adaptation of Hilger-Watt large dispersion spectrograph for i5N determination. Carbon calorimeter for determination of high energy radiation absorbed dose. One absorbed dose calorimeter made from TEM-Material — upon request from the Government of New Zealand. Parallel plate secondary standard ionization chamber made of carbon. Automatic 4гг /З-Y-coincidence counting equipment.

The scientific staff would like to express its gratitude to its colleagues of the Mechanical Workshop, whose helpful co-operation has been warmly appreciated.

5. PUBLICATIONS BY STAFF MEMBERS

BERGERHOFF, G., FERRARIS, M., MERTEN, D., QualitStskontrolle analytischer Methoden im internationalen Rahmen, Z. analyt. Chem. 222 2 (1966) 131.

BERGERHOFF, G., FERRARIS, M., MERTEN, D., Some critical remarks on environmental radioactivity measurements, Giornale di Fisica Sanitaria e Protezione Controllo Radiazioni 10 2 (1966) 157-62. VIENNA AND SEIBERSDORF 93

CZOSNOWSKA, W.24, Anion exchange behaviour of alkaline earth elements in dioxane-water-hydrochloric acid and dioxane-water-perchloric acid media (in press).

GALATZEANU, I., Etude de la formation des complexes du protactinium avec les acides di-et-poly- carboxyliques par la méthode d'échange d'ions, Can. J. Chem. 44 (1966) 647.

GALATZEANU, I., "The effects of gamma radiation on folic acid", Proc. Second Symp. on Radiation Che- mistry, Tihany, Hungary, 15-19 May 1966, Akadémiai Kiadó, Budapest (1967) 55.

GALATZEANU, I., ANTONI, F., Les effets des radiations gamma sur la vitamine B6, Int. J. appl. Radiat. Isotopes 17 (1966) 369.

KEROE, E. A., MUTZ, O., 3-stage pulse limiter has short recovery time. Electron. Des. 14 13 (1966) 86.

MAUNOWSKI, J., Precise determination of uranium in pure uranium and uranium compounds by constant current coulometric titration, Talanta 14 (1967).

MONRO, J., Population flushing with sexually sterile insects, Science 151 (1966) 1536-38.

MONRO, J., The exploitation and conversation of resources by populations of insects, J. Anim. Ecol. (in press).

MONRO, J., Insect marking with dietary manganese for neutron activation (submitted to Nature).

NADEL, D.J., MONRO, J., PELEK, B.A., FIGDOR, H.C., A method of releasing sterile Mediterranean fruit-fly from aircraft, J. appl. Ent. (in press).

PERSCHKE, H., Tritium enrichment by gas chromatography, Nature (London) 209 (1966) 1021.

PERSCHKE, H., A simple technique for the hydrogénation of ethylene, Int. J. appl. Radiat. Isotopes 17 (1966) 358.

PSZONICKI, L., Precise titrimetric determination of uranium in high purity uranium compounds, Talanta 13 (1966) 403.

SUSCHNY, O., Die LuftradioaktivitSt und ihre Messung, Allg. Prakt. Chemie 17 (1966) 367.

6. PAPERS PRESENTED AT SCIENTIFIC MEETINGS BY STAFF MEMBERS

COOK, G.B., GALATZEANU, I., Study of the autodecomposition of iodine-131 labelled Rose Bengal and thyroxine, Radiochemical Conference, Bratislava (CSSR) 6-10 Sept. 1966.

COOK, G.B., GALATZEANU, I., "Contrôle de la pureté radiochimique du Rose Bengale et de la thyroxine marqués 5 l'iode-131", Proc. Second Int. Conf. on Methods of Preparing and Storing Labelled Compounds, EURATOM, Brussels, Belgium, 28. Nov. - 3 Dec. 1966.

GALATZEANU, I., "The effects of gamma radiation on folic acid", Proc, Second Symp. on Radiation Che- mistry, Tihany, Hungary, 15-19 May 1966, Akadémiai Kiadó, Budapest (1967) 55.

GALATZEANU, I., ANTONI, F., "Les effets des radiations gamma sur la vitamine B6", Proc. Third Int. Congress of Radiation Research, Cortina d'Ampezzo, Italy, 26 June - 2 July 1966.

HOUTERMANS, H., MIGUEL, M., WERNER, E., "Fast testing of radiation counter performance by single- channel counting". Standardization of Radionuclides, IAEA, Vienna (1967) 115.

24 IAEA Fellow from Central Laboratory for Radiological Protection, Warsaw, Poland. 94 VIENNA AND SEIBERS DORF

JAEGER, R.G., NAGL, J., SANIELEVICI, A., Das Dosiskalorimeter der IAEO und die Frage der Dosismessung in rad, 47th Session of the Deutsche Roentgengesellschaft, 18-21 May 1966, Berlin.

MERTEN, D., BERGERHOFF, G., FERRARIS, M., "Analytical quality control and milk contamination survey", Radioisotopes and Radiation in Dairy Science and Technology, IAEA Vienna (1966) 177.

MIGUEL, M., HOUTERMANS, H., "Influence du retard sur le taux de coincidences". Standardization of Radionuclides, IAEA, Vienna (1967) 135.

PETEL, M., HOUTERMANS, H., "Méthodes d'indicateur pour l'étalonnage du fer-55". Standardization of Radionuclides, IAEA, Vienna (1967) 301.

SANIELEVICI, A., NAGL, J., "Calorimetric determination of absorbed dose for high energy radiation and comparison measurements", Proc. Symp. sobre Terapia de Megavoltaje y Electrones muy Acceletados, Madrid, 26-28 Sept. 1966.

SCHAERF, K., "Standardization of thorium-230 by filter-paper liquid scintillation counting", Standardization of Radionuclides, IAEA. Vienna (1967) 65.

SCHAERF, K., HOUTERMANS, H., "On the feasibility of low-threshold liquid scintillation counting", Proc. Symp. on Liquid Scintillation Counting at the National PhysicabLaboratory, Teddington, UK, 18-19 Oct. 1966.

SCHAERF, K., VUORINEN, A., "Determination of the thickness of thin layers", Standardization of Radio- nuclides, IAEA, Vienna (1967) 543.

SUSCHNY, O., DieMessung der Luftradioaklivit&t, to the "Arbeitsgruppe Radiochemie und Strahlenchemie" of the Verein Osterreichischer Chemiker, 16 March 1966.

SUSCHNY, O., FRITTUM, H., EISENLOHR, H., "Radiation dosimetry by measurement of the change in rotation of opticallyractive substances", Solid State and Chemical Radiation Dosimetry in Medicine and Biology, IAEA, Vienna (1967) 317.

VUORINEN, A., "Calibration of I03mRh by the coincidence method," Standardization of Radionuclides, IAEA, Vienna. (1967) 257. THE INTERNATIONAL LABORATORY OF MARINE RADIOACTIVITY AT MONACO

I. INTRODUCTION

The field and laboratory research of the International Laboratory of Marine Radioactivity at Monaco was in 1966 concerned with the problem of the distribution of radionuclides in the sea as a function of time and space, the chemical behaviour of radionuclides of various chemical states in sea- water, the distribution and accumulation of radionuclides by the various com- ponents of marine biota, and the interchange of radioisotopes between the sea-bottom and the bottom-water. As in the past, co-operation with the Centre Scientifique de Monaco and the Institut Océanographique de Monaco has been both smooth and effective. This also applies to other Mediterranean Institutes concerned with problems related to radioactivity in the sea, particularly the Laboratory of the Comi- tato Nazionale per l'Energia Nucleare, Fiascherino (Italy), and the Institute 'Ruder BoSkovic', Rovinj. (Yugoslavia). In the second half of the reporting year the Director General appointed an ad hoc committee of scientists1 to study the work and future of the laboratory. This panel warmly supported the work of the Monaco Laboratory and stressed the need for it. Its recommendations were reported in the information paper GOV/INF/171 of 31 January 1967. Staff members of the Laboratory participated in, and acted as Session Chairmen of, the Committee on Marine Radioactivity during the XX th Congress of the Commission Internationale pour l'Exploration Scientifique de la Mer Méditerranée held at Bucarest. Seven other international meetings were attended by scientists of the Monaco Laboratory during the reporting period. During November the periodic contact group meeting between the laboratories of Fiascherino, Rovinj and Monaco was held at Monaco with a number of guests from other outside laboratories. Fourteen papers were presented and interesting discussions took place. Sixty scientists and dignitaries from fifteen different countries (Argen- tina, Austria, Belgium, Canada, Czechoslovakia, Finland, France, India, Italy, Japan, Korea (South), Sweden, United Kingdom, USA and USSR) visited the Laboratory and in many cases discussed different aspects of the work.

1 Composed of E.B. Kullenberg, Océanographie Institute of the University of GOteborg, Sweden; J. Cousteau, Musée Océanographique, Monaco; А.В. Joseph, USAEC, Washington, D.C., USA; and R. Spann, Oesterrelchische Studiengesellschaft fflr Atomenergie, Vienna, Austria.

97 II. RESEARCH

1. WORK AT SEA

With the 'Winnaretta Singer1, a small boat owned by the Musée Océano- graphique, seven cruises were made to carry out routine investigations near Monaco. Of great help indeed was the three-week visit of the new German research vessel 'Meteor' (2600 BRT) at Monaco (Fig. 1). Together with the scientific staff of the German Hydrographie Institute and with scientists of the Centre Scientifique de Monaco, of the Institut Océanographique de Monaco and of the Laboratoire de Mécanique des Fluides, Grenoble, the staff of the Laboratory carried out large-scale diffusion investigations, observations of the content of radioactive material in different depths down to 2500 metres, studies of the possible vertical transport of radionuclides by animals, sedimentological studies and hydrographical and current measurements.

FIG. 1. 'Meteor* in the port of Monaco

1.1. Diffusion processes in the sea

The 'Monaco method' of studying small-range diffusion processes2 was further developed and a first simple instrument was constructed to extend the tests to greater depths. A preliminary report is in preparation.

! INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No.55, IAEA, Vienna (1966) 104.

98 MONACO 99

Large-range diffusion studies constituted the main point of the 'Meteor1- programme. The general purpose of these investigations was to estimate the influence of tides on diffusion processes in the sea by comparing the results of diffusion experiments in areas of strong tidal currents, like the North Sea, with areas of little or no tidal current like the Mediterranean Sea. In two instances, 250 kg of the dye-stuff Rhodamine В in solution was dropped in a very small surface area so that it could be considered as a point source. The horizontal and vertical distribution of the Rhodamine with time was continuously recorded during one week. Simultaneously the horizontal and vertical distribution of physico-chemical parameters like temperature, salinity, oxygen, etc . between the surface and the bottom were observed and current observations with self-recording current meters were made. In spite of the bad weather, with winds up to Beaufort 9-10, good results were obtained which are now processed. As a preliminary result, it can be said that the Rhodamine spread in longish patches. The longitudinal extent of these patches was after two days to be about 9 km, after three days 15 km and after four and a half days 23 km. Together with this extension occurs the expected diminution of the maximum intensity with time t of the test material. This intensity seems to follow an exponential law. Of special interest was the vertical distribution of the test material. The so-called thermocline, where the temperature changes very rapidly, was observed between 20 and 30 metres depth with a temperature difference of about 6°C. To this high temperature gradient corresponds a relatively high density gradient, which stopped the vertical diffusion nearly completely. Thus, after one week, no test material could be observed below the depth of the thermocline. The conclusion is that any kind of polluting matter, either radioactive or not, introduced into the surface layer of the sea can be distributed very rapidly over a great area without passing the thermocline and reaching greater depth. This result, even though preliminary, is certainly of importance in considering the fate of any radioactive waste or effluent dis- charged into the Mediterranean. The exact figures for the different diffusion coefficients are in calculation.

1. 2. Organic aggregates

The organic aggregates found in sea-water can be associated with various radionuclides and therefore investigations on their abundance and their relation to some physico-chemical and biotical parameters off the Monaco coast were continued up to October. Compared with parts of the North Atlantic, the quantities of aggregates present (1 -52 mm2/litre) were not as great as those recorded for coastal areas, but compared favourably with the more open-sea areas. Some seasonal variations were evident and may be correlated with an abundance of phytoplankton and chlorophyll a, and with a decrease in temperature and salinity.

1. 3. Vertical transport of radionuclides by biota

In almost all seas and oceans the existence of a special layer, charac- terized by back-scatter of sound, is established. The tiue nature of this 100 MONACO

'back-scattering layer' is not clear, but it seems that it is associated with some animals, especially euphausiids. The particular characteristic of the back-scattering layer is its vertical daily migration, which in some cases amounts to 400 metres; usually it is close to the surface during the night and sinks during the day-time. Since the diffusion of radionuclides by biota and physical diffusion are usually horizontal in nature, the transport of radionuclides by organisms associated with the deep scattering layer might be an important path of rapid vertical transport. Therefore a programme was set up for studying the significance of the radionuclide transport by organisms which might be connected with the deep scattering layer. In the frame of this programme at the beginning of November one member of the Radiobiology Section took part in a seven-day cruise of the German oceanographic ship 'Meteor' in the Ligurian Sea. During the cruise an attempt was made to correlate the deep scattering layer with zooplankton catches, especially euphausiids. Besides this, laboratory experiments concerning the uptake and retention of 54Zn by copepods (Anomalocera) and euphausiids (Meganyctiphanes) were started.

2. WORK IN THE LABORATORY

2.1. Chemistry of sea-water

The objectives of the chemical studies of sea-water in the Monaco La- boratory are focused on obtaining qualitative as well as quantitative know- ledge of the chemical behaviour of radionuclides in sea-water medium. This kind of information is important not only for the scientific understanding of chemical processes occurring in sea-water, but also for the practical consideration of problems such as control of radioactive waste disposal into marine environments. For example, the 'concentration factor', which indicates the degree of concentration of a radionuclide from sea-water in a certain marine organism and which is being used as the basis for the prediction of the level of radionuclide in marine food products, cannot be determined without considering the chemical forms of radionuclides occurring in sea-water medium. In this sense, some experimental estimations of the 'concentration factor' for radionuclides in the past may have been misleading. Furthermore, based on these inadequate figures, the practical permissible concentrations of some radionuclides have already been set up in certain areas of nuclear operations. From this point of view it seems urgent to evaluate the quantitative contribution of individual chemical forms of certain radionuclides to the cycles of those radionuclides in sea-water as a whole. Thus a sound basis may be found for the practical consideration of radioactive waste disposal into the sea. The approach in 1966 to the problem was made simultaneously from two different directions: that is, first from the determination of various chemical forms of trace elements in water samples collected in situ, and sécond from laboratory experiments on the chemical behaviour of important radionuclides in sea-water medium. MONACO 101

In the first group, previously developed methods of trace analysis for cobalt and chromium were applied to several sea-water samples collected from the Ligurian Sea. At the same time methods of analysis for trace quantities of silver and manganese were developed and applied to sea-water samples. In the second method of approach, studies were concentrated on the chelation processes of various radionuclides with organic molecules. An outline of the progress of these studies is given in the following section.

2.1.1. Determination of trace elements in sea-water

Determination of cobalt. The procedure for the enrichment of trace amounts of cobalt on solid manganese dioxide has been applied to the determination of cobalt in sea-water samples. In order to understand the geochemical behaviour of cobalt in the hydrosphere as a whole trace amounts of cobalt in river waters were also measured. The results of these determinations show that the cobalt content of sea-water in the Ligurian Sea does not vary very much with locality or depth, being of the order of 0.1 /ug Co/litre.

Determination of chromium. The separate determination of trivalent and hexavalent chromium was applied to sea-water samples taken at various localities of the Ligurian Sea. The results obtained indicate that hexavalent chromium is found in all samples analysed, although the fraction of hexavalent chromium in total chromium varies from one sample to another. In eight out of nine samples analysed the hexavalent chromium predominated or was at least comparable to the trivalent chromium. In summary, the total chromium content of sea-water seems to be up to 0. 5 /ug Cr/litre. In the past the chromium content of sea-water was believed to be less than 0. 1 Mg Cr/litre, probably because no attempt was made to determine hexavalent chromium. This new information seems to be important and basic for the control of the radioactive waste disposal of some nuclear installa- tions, since 51Cr is actually being introduced into marine environments in some areas. At present systematic variation of the chromium content of sea-water with locality and depth was not found. Hexavalent chromium was also found in river water entering the Ligurian Sea.

Determination of silver. A method for the analysis of trace amounts of silver in sea-water was developed by using co-precipitation with lead sulphide. After the co-precipitation lead was removed as sulphate and silver was pu- rified by extraction with dithizone. The colour of dithizonate of silver was measured spectrophotometrically. Although the sensitivity of the method is not sufficient to ascertain minor changes of silver content of sea-water, it is possible to determine the order of magnitude of silver concentration. The results obtained by this method for some water samples collected from the Ligurian Sea revealed the silver content to be around 0. 1 jug Ag/litre, which is smaller than that obtained for some parts of the Atlantic and Pacific by other workers. Improvement of the sensitivity of the method will be achieved by the introduction of radioactivation techniques.

Determination of manganese. The technique of enrichment of trace elements with chelating resin from sea-water was applied to the determination of man- 102 MONACO

gañese. Values obtained by this method for soluble manganese in the water samples collected in coastal areas around Monaco were about 2 /ug Mn/litre, showing good agreement with the data obtained by other authors with other methods. By collaboration with the Agency's Laboratory at Seibersdorf, preliminary radioactivation analyses of resin treated with sea-water were carried out. After chemical separation using anion-exchanger the irradiated resin samples were assayed gamma-spectrometrically. The peaks of 51Cr, 56Mn, 64Cu, and 69Zn were detected and the interfering 24Na peaks were not so serious as expected. These results suggest that the pre-concentration procedures for trace elements in sea-water with the chelating resin may find a good application in the field of trace analysis of sea-water by using radioactivation techniques.

2.1.2. Laboratory experiments on the behaviour of radionuclides in sea-water medium

As stated above laboratory experiments on the behaviour of radionuclides in sea-water medium were aimed at the quantitative understanding of chelation reactions of metallic radionuclides such as 51 Cr, 54Mn, 59Fe, 60Co and 65Zn, with organic molecules. As a model of chelate-forming organic molecules EDTA was chosen, since the stability constants of the chelate compounds of this substance with many metals are already well established so that quantitative calculations of chelate formation are possible. Although it is clear that conclusions drawn from the results of these experiments could not immediately be generalized to the process of chelate formation in situ, still some information on the general process could be obtained.

Theoretical consideration of chelate formation. The processes of chelate formation in sea-water medium are very complex, since sea-water contains ions such as calcium and magnesium, in large quantities competing with the trace metals. In order to guide the interpretation of the experiments, a theory of chelate formation in sea-water medium was developed and com- putations of chelate-formation equilibria for divalent metallic ions were carried out. The discrepancy between theoretical and observed values suggests the importance of kinetic factors, as yet unaccounted.

Experimental studies on divalent cations. The experiments were carried out mainly on divalent cations such as manganese, cobalt and zinc. To separate the uncombined ions from chelated molecules adsorption on manganese dioxide, dialysis and electrophoresis were applied. The results obtained in distilled water showed that the percentage of uncombined ions of the metals concerned agreed with theory in the relatively higher range of concentrations (greater than 100 /ug/litre) in experiments of several hours duration, while in the relatively lower range of concentrations (less than 10 jug/litre) much longer times were required before equilibria had been reached. In sea-water medium the theoretical equilibria could not be reached within 100 hours even in the relatively higher range of concentrations. Some examples of chelate formation of cobalt with EDTA in sea-water medium during the course of time are illustrated in Fig. 2. MONACO 103

These experimental results suggest that the process of chelate formation should be slow and that the kinetics of the reaction would be very important in understanding the actual process in sea-water, especially in the lower range of concentrations. If chelate formation between these metallic ions and EDTA could be regarded simply as a second-order reaction, periods from several weeks to several tens of years will be required before equilibria will have been reached, depending on the concentration of the metals in situ and the stability of the chelate compounds. These lengths of time are fairly long considering the chemical behaviour of radionuclides during an initial period of introduction into sea-water, although they are relatively short in comparison with the geochemical cycle of trace elements in marine environments.

FIG.2. Chelate formation of cobalt with EDTA in sea-water as a function of time

2.1.3. Conclusions

Although the results obtained so far in the studies described above are preliminary, they are important for the practical consideration of the problem of radioactive waste disposal in the future. The points raised from the present studies are summarized as follows: (a) By developing methods of analysis for several trace elements in sea-water, the methodological basis for further studies on the chemical behaviour of the corresponding radioisotope has been obtained. (b) The 'concentration factor' for cobalt and chromium, which had been estimated on the basis of stable-elements contents of these elements in sea- water and marine organisms, should be revised on the basis of the new data obtained. In the past cobalt contents of 0.5 iug/litre and chromium contents of 0.05 Mg/litre have been frequently taken as the basis for sea-water. These figures should be replaced by 0. 1 Mg Co/litre and 0. 5 Mg Cr/litre, respectively. (c) It has been made clear that in the consideration of both the chemical behaviour of chromium and its link with marine food chains the occurrence of stable hexavalent chromium in sea-water has to be taken into account. 104 MONACO

(d) It has been pointed out that kinetic factors are important in the consideration of chelation processes in sea-water. The assumption that radionuclides introduced into sea-water are immediately chelated with organic molecules should be reconsidered in the light of our kinetic studies.

2. 2. Chemistry of sediments

2.2.1. The penetration of radionuclides into the sea-bottom (Diffusion and sorption problems)

The behaviour of radionuclides on the sea-bottom is related to the chemical and microbiological processes in the bottom sediments, which processes are closely related to each other but difficult to distinguish. However, the low temperatures at the bottom of the ocean (2 -4°C) do not permit high bacterial activity and chemical processes are relatively more important. On the continental shelf in warm seasons the higher temperature shifts this relationship. The behaviour of radionuclides in the sediments depends greatly on the possible kinetic mechanisms of transport. Mainly it occurs by molecular diffusion, but in bottom areas or intertidal flats molluscs, worms, etc. have also a mechanical effect on the sediment. This molecular diffusion takes place only in the interstitial water in which the freedom of dissolved unad- sorbed compounds and ions to move is reduced relative to a free solution. However, this reduction is less than one would expect and not more than one order of magnitude lower for the coefficient of diffusion (free solution about 3X10-5 cm2 /s; interstitial water of sediment 10'6-10'5 cm2/s). Naturally for coarse and fine sediments the coefficients differ. Quantitatively these factors are of limited use for the description of the overall behaviour, if the radionuclides should also be adsorbed on or absorbed by the sediment particles. Then, as we mentioned in the previous annual report3, the factors have to be corrected: this is possible if the distribution of the radionuclides between the sorbed state and the solution can be determined.

2.2.2. Experimental

The experimental study of this problem was the main task in 1966. Sorp- tion effects depend on temperature, concentration, pH value andtime, and other factors, and make a practical evaluation of the study of the penetration of radionuclides into sediments very complex. On the other hand it is necessary to find simple methods for routine work, which produce reasonable results in relation to the desired, accuracy for the description and prediction of the penetration. The experiments can be divided into three parts. First, experiments on diffusion itself. Second, experiments on sorption and third, chemical methods of characterizing the sediments.

3 INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No.55, IAEA, Vienna (1966) 109-11. MONACO 105

The diffusion experiments aimed to investigate primarily whether transport of radionuclides in interstitial water of sediments can be described by diffusion laws; further, to arrive at methods which would be applicable to in situ situations and which would be as simple as possible. The first difficulty is that, for radionuclides which are sorbed by the sediment particles, any transport is so slow that a rapid determination is not possible. There- fore a method was developed to combine diffusion and sorption experiments, the former done with chloride and the latter with tracers only. Without going into great detail, it may be concluded that chloride diffusion experiments show quite accurate results for different types of sediments, and agree well with the data of other investigators. The relation of these experiments to in situ diffusion in sediments in great depths will be investigated next year. The values for diffusion coefficients found are between 0.3-1.0 X 10~5 cm^/s, depending on the type of sediment. From the sorption experiments it may be concluded that representative results are very difficult to obtain. Most of the cobalt experiments with sus- pensions of sediments under different conditions of pH value, concentration of carrier, concentration of sediment, and time of sorption showed variable results and indicated that better methods were necessary. Sucking the solutions through layers of sediments gave better results, but this method is not practical for routine studies. For this reason a method with small quantities of sediment (some milligrams) was tried and found to give better results. Bacterial influences on sorption experiments are important but can be avoided when the experiments are done at low temperatures (2 -5°C). For different types of sediments and radioisotopes the overall diffusion coefficients may be quite different. As far as we have investigated they may vary between 10"10 and 10"6 cm2/s. Next year we will be investigating the behaviour of ten radioisotopes in about thirty or forty characteristic ocean sediments, which will be supplied by a number of co-operating oceanographic institutions of several countries. For this work a number of chemical methods were tested for the routine characterization of the sediments by their chemical and geological properties.

2.2.3. Conclusions

The experimental investigations have given reasonable agreement with theoretical calculations on the diffusion of radionuclides in sediments. It is therefore possible to do a large-scale investigation with ten important radionuclides, viz. 90Sr, is^Cs, "6 Ru, 59pe, 65Zn, босо, 54Mn, 95Zr, 144Ce and 147Pm, and several characteristic deep ocean and shallow sea sediments. The methods developed to study diffusion and sorption are simple. The accuracy is at least sufficient for the discovery of general relations and orders of magnitude of the possible penetration of radioisotopes in sea-bottom sediments.

2. 3. Radiobiology of marine organisms

The activity of the Radiobiology Section continued along the same general line as in previous years, but some new topics were introduced. 106 MONACO

Realizing that understanding fundamental processes, such as (a) the role of organic aggregates in concentrating radionuclides, (b) the possibility of vertical biological transport of some radionuclides taken up by biota associated with the deep scattering layer, (c) the mechanism of uptake, accumulation and loss of radionuclides by animals, (d) the relation of the physico-chemical form of radionuclides to their availability for marine organisms, is today an urgent need, field observations and laboratory experiments were not directly connected to any local problem, but were chosen as models of problems of general interest.

2.3. 1. Uptake, accumulation and retention of manganese-54 by the clam and an annelid worm

The extensive studies done on the uptake, accumulation and retention of radiomanganese by a clam (Tapes decussatus) and a marine annelid worm (Hermione hystrix) were finished. The results are in press. In experiments with the clam the often neglected role of micro-organisms, living on the free surface of the animals, in the accumulation of 54Mn was pointed out. The experiments indicated that the accumulation of the radioactivity by the shells of bivalves is due in part to the accumulation by bacteria or other organisms associated with the shell surface, and that the concentrating ability of epiphytes on the body surfaces of many benthic marine organisms can play an important role in the observed accumulation of radioactive materials by these organisms. The analyses of the mechanism of 54Mn exchange and accumulation in Hermione considered the uptake of radiomanganese with different concentrations of manganese in the water and different forms of the radionuclide in the bottom silt in which the worms were held. It was found that Hermione very rapidly took up 54Mn in the form of the divalent cation and concentrated it to extremely high levels. The loss of the incorporated activity was very slow indicating an incorporation of the radionuclide into a body component having a slow physiological turnover time. When 54Mn was present in organic particles added to the bottom silt, the accumulation in the animals was considerably lower, and 54Mn present in the bottom silt as Mn02 was practically not taken up by the animals.

2.3.2. Radioecology of manganese-54

The occurrence of fallout 54Mn was analysed and compared with the analyses of the total manganese content in various marine biota. The biota were mainly collected along the Ligurian coast, and in August a short cruise was made to Corsica with the 'Winnaretta Singer1 to collect some bivalves for these studies. A rather high manganese content was found in some species examined, such as the ascidian Halocynthia papillosa (80 mg Mn/g of ash), the mollusc Pinna nobilis (22 mg Mn/g of soft tissue's ash) and the annelid worm Hermione hystrix (1.5 mg Mn/g of ash). In addition the fallout йМп content MONACO 107

in these animals was usually high, indicating that - in one species at least - the 54Mn is in a form exchangeable with the non-radioactive isotope of the same element (Fig.3).

FIG, 3. Gamma-energy scan of the ash from Pinna nobilis mantle

2.3.3. Chromium-51 metabolism in clams

Experiments concerning the uptake and accumulation of 51 Cr by the clam (Tapes decussatus) in relation to the physical and chemical form showed that clams exposed to sea-water containing radiochromium as trivalent chromic chloride rapidly became radioactive from adsorption and their filtering activity. The radioactivity was not filterable when the complexing agent EDTA was added to the basins because the formation of radioactive particles by precipitation was thereby prevented. The addition of 51 Cr in the form of hexavalent sodium chromate to sea- water resulted in a solution of radioactive ions. The radionuclide in this form was rapidly taken up by the clams through the adsorptive surface of the body. The amount of chromium and 51Cr entering the animals was related to the concentration of the element in the sea-water, accumulation apparently being a passive process. The greater part of the radioactivity was accumulated within the soft body tissues. The radionuclide was tightly bound in some tissues and the biological retention time of the radioactivity was long when the animals were returned to normal sea-water.

2. 3.4. Cycling of zinc-65

Investigations were started concerning the transport of 65Zn directly from the sea to some selected marine animals (clam, Tapes decussatus and a crab, Pachygrapsus marmoratus). In both animals a multi-compartmental zinc metabolism has been found resulting in complicated uptake and loss processes. The uptake was rapid but the equilibrium in radiozinc exchange between the animals and the experimental basins was not reached after 40 days. The los s of incorporated radiozinc had an initial rapid and short and a later slow phase. The overall rate of radiozinc loss was found in both animals to be dependent on the duration of its uptake previous to the loss experiments; it was higher in animals which had been in contact with the 108 MONACO radioisotope for only a short period. In addition, it was shown that the surface adsorption of radiozinc in crabs plays only a minor role in the overall uptake of this radionuclide. Chemostat plankton culture and field experiments are planned to complete these investigations. III. ADMINISTRATIVE MATTERS, STAFF MEMBERS AND PUBLICATIONS

1. SITE, FACILITIES AND EQUIPMENT

At the end of 1966, the Laboratory got a new large room for the radio- sedimentological section and has now at its disposal 17 rooms totalling 218 m2. In the event that the staff of the Laboratory was increased as recommended by the ad hoc committee (GOV/lNF/171 of 31 January 1967), new laboratory space would be made available by the Musée Océanogra- phique at its own cost on a proportional basis. The equipment of the Laboratory was slightly augmented during 1966. Of special value was a gift kindly offered by the Swedish Government containing among other items one laboratory centrifuge complete with guard bowl, autotransformer time-and-angle head, and one centrifuge complete with rotation heads; an automatic fraction collector (Radi-Rac Universal); a column electrophoresis apparatus; paper electrophoresis equipment; three pumps, two intensimeters complete with wooden carrying case; and one microscope, stereoscopic.

2. FINANCE

The budget

For the financial period 1 January to 31 December 1966 the Monaco Laboratory had at its disposal funds totalling US$139 990. Of this amount $92 761 were provided from the Agency's regular budget; the Government of Monaco provided a contribution of $44 898 covering its annual contractual commitment. The balance arose from savings on prior years' operation.

Expenditure

The expenditure and obligations during 1966 for the project were as follows:

US$ Salaries and other staff costs 120 976 Library acquisitions 496 Scientific services, supplies and equipment 10 447 Duty travel 3 254 General services and supplies 4 817

TOTAL 139 990

109 110 MONACO

3. PROFESSIONAL STAFF OF THE LABORATORY

JOSEPH, Joachim (Federal Republic of Germany)

Bom 1910; University of Leipzig; M.Sc, (mathematics, physics, geophysics), Dr.rer.nat. (oceanography).

Regierungsdirektor and Head of the Oceanographical Department of the German Hydrographie Institute , Hamburg,

Director, responsible for the scientific programme, the administration and external relations with govern- mental and scientific agencies in matters related to the fields of activity of the Laboratory.

CHIPMAN, Walter A. (United Sutes of America)

Born 1903; M.Sc. (zoology), University of New Hampshire; Ph.D. (physiology), University of Missouri.

1949-1960 Director of the Radiobiological Laboratory of the US Bureau of Commercial Fisheries at Beaufort, North Carolina; 1960-1961 Atomic Energy Advisor of the US Fish and Wildlife Service, Washington, D.C.

Radiobiologist conducting research in problems of a fundamental nature on the biological accumulation of radionuclides, and responsible for the work of the Radiobiological Section of the Laboratory.

DUURSMA. Egbert, Klaas (The Netherlands)

Born 1929; Free University, Amsterdam (chemistry, oceanography, psychology).

1956-1965 chemical oceanographer, Netherlands Institute for Sea Research, Den Helder. Joined the Laboratory on 1 February 1965.

Marine radiochemist conducting research of fundamental nature on the chemical and physico-chemical uptake and accumulation of radioisotopes in marine sediments.

FUKAI, Rinnosuke (Japan)

Born 1925; University of Tokyo; Ph.D. (chemistry).

Section Chief of Chemical Oceanography and former Chief of Radioisotope Laboratory, National Fisheries Laboratory, Ministry of Agriculture and Forestry, Japan.

Marine radiochemist, responsible for the radiochemical aspects of the problems of the Laboratory, including chemical analysis of sea-water and of marine organisms.

KE&KeS, Stjepan (Yugoslavia)

Bom 1932; University of Zagreb; Ph.D. (biology). Joined the Laboratory on 1 September 1966.

Head of the Laboratory of Marine Radiobiology, Institute 'Ruder Boíkovií', Rovinj, Yugoslavia (1963-1966).

Marine radiobiologist, conducting research on general problems of biological transport of radionuclides. MONACO 111

4. PUBLICATIONS BY STAFF MEMBERS

CHIPMAN, VI.A., Food chains in the sea, Radioactivity and Human Diet (RUSSEL, R. Scott, Ed.), Pergamon Press, Ltd. (1966) 410-53.

CHIPMAN, W.A., "Uptake and accumulation of Cr51 by the clam, Tapes decussatus, in relation to physical and chemical form", Disposal of Radioactive Wastes into Seas, Oceans and Surface Waters, IAEA, Vienna (1966) 571-82.

CHIPMAN, W.A., "Some aspects of the accumulation of chromium-51 by marine organisms", Radioecological Concentration Processes, Pergamon Press, Ltd., London (1966) 931.

DUURSMA, E.K., "Molecular diffusion of radioisotopes in interstitial water of sediments", Disposal of Radio- active Wastes into Seas, Oceans and Surface Waters. IAEA, Vienna (1966) 355-71.

DUURSMA, E.K., SEVENHUYSEN, W., Note on chelation and solubility of certain metals in sea water at different pH values, Neth. J. Sea Res. Ш. p.95-100.

FEDOROV, A.p., Natural radioactivity in some ocean regions, Bull Inst, océanogr. Monaco 64 1335 (1965).

FUKAI, R., Remarks on the chemical problems in relation to the marine radioactivity, Rapp. P.-v. Réun. Commn int. Explor. scient. Mer Méditer. 18 3 (1966) 861-63.

FUKAI, R., Comments on Dr. Sugiura's "reserved nutrients", J. oceanogr. Soc. Japan 22 (1966) 17-19.

FUKAI, R., "Fate of some radionuclides fixed on ion-exchange resins in sea-water medium". Disposal of Radioactive Wastes into Seas, Oceans and Surface Waters, IAEA, Vienna (1966) 483-95.

FUKAI, R,, Some aspects of chemical cycle of radioactive chromium and cobalt in sea water (abstract), Second International Océanographie Congress, Abstract of Papers, Publishing House "Nauka", Moscow (1966) 124-25.

FUKAI, R., Some biogeochemical considerations on the radioactive contamination of marine biota and en- vironment (abstract), First International Congress of IRPA, Abstracts of papers presented at the Congress, Pergamon Press, Ltd., New York - Oxford (1966) 27.

FUKAI, R., Activities of Monaco International Laboratory (in Japanese), Shizen 21 5, p.50-53.

FUKAI, R. .HUYNH-NGOC, L., VAS, D., Determination of trace amounts of cobalt in sea-water after enrichment with solid manganese dioxide. Nature, London 211 (1966) 726-27.

GILAT, E., KANE, J., MARTIN, J.C., Study of an ecosystem in the coastal waters of the Ligurian Sea. П. Surface zooplankton, Bull. Inst, océanogr. Monaco 65 1353 (1965).

KECkeS, S., PUCAR, Z., KOLAR, Z., The turnover of sodium by some flsh, Yugoslav, physiol. pharmacol. Acta 1 (1966) 87-94.

KEÍKES, S., FUCAR, Z., MARAZOVIÍ, Lj., "The influence of the physico-chemical form of Rul06on its uptake by mussels from sea-water", Radioecological Concentration Processes, Pergamon Press, Ltd., London (1966) 993-94.

THE INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS, TRIESTE

I. INTRODUCTION

During the period under review research was done at the Centre in elementary particle physics and plasma physics. Earlier work in elementary particle physics was continued. Many contributions to the relativistic generalization of SU(6), non-compact groups, the representation theory of compact and non-compact Lie groups, potential scattering, some aspects of quantum electro-dynamics, dispersion relations and algebra of currents were made. A large plasma physics group under the leadership of M. N. Rosenbluth (USA) and R.Z. Sagdeev (USSR) was set up for one year. Many aspects of this field were investigated, e.g. the theory of plasma stability, instabilities in inhomogeneous plasmas, the quasi-linear theory of 'whistlers', shock waves in collisionless plasmas, etc. The Centre is still housed at 6, Piazza Oberdan, but the new air- conditioned building under construction at Miramare will be ready in 1967. More rooms and larger lecture halls will then be available. The Computer Centre of Trieste hasnowanIBM-7040 computer which is at the disposal of members of the Centre at a special rate.

115 П. ASSISTANCE ТО DEVELOPING COUNTRIES 1

1. ASSOCIATE MEMBERSHIPS

The Centre has established an Associate Membership system by which worthy physicists from developing countries may spend up to four months per year at the Centre at a time of their own choice with no formality except a letter to the Director. This system permits such physicists to maintain close contact with modern science and encourages them to spend the major part of their time in their home countries. Associate members are appointed by the Scientific Council upon proposal by the Director of the Centre. As yet Associate Memberships have been granted to nine physicists: F. Gürsey (Turkey), Riazuddin (Pakistan), I. Saavedra (Chile), V. Singh (India), J. Tiomno (Brazil), B.M. Udgaonkar (India), Fayyazuddin (Pakistan), J.J. Giambiagi (Argentina) andD.A. Akyeampong (Ghana).

2. FELLOWSHIPS AND OTHER POSITIONS

Out of a total of twenty Fellowships (thirteen for the elementary particle physics group and seven for the plasma physics group) thirteen were awarded to individuals from twelve developing countries (seven for the elementary particle physics group and six for the plasma physics group). Thirteen visiting scientist positions have been offered to scientists from eight developing countries and thirteen guest lecturers from five developing countries have been invited. For the academic year 1965/1966 a total number of nineteen developing countries have benefited from the assistance of the Centre.

3. THE ADVANCED SCHOOL OF PHYSICS

The Advanced School of (Theoretical) Physics is со-sponsored by the International Atomic Energy Agency, the United Nations Educational, Scien- tific and Cultural Organization and the University of Trieste. Its programme of courses is similar to that of an American graduate school. A diploma is awarded to students who have successfully passed the examinations and written a thesis which can be submitted as a paper to an international scientific journal. Six Fellows from developing countries enrolled in the school in 1965-1966. The programme of the school for that year is shown in Table I.

1 For the purpose of this report, countries receiving technical assistance under the Enlarged Programme for Technical Assistance (EPTA) are considered as developing countries.

116 TRIESTE 117

TABLE I. PROGRAMME OF COURSES AT THE ADVANCED SCHOOL OF PHYSICS

Title of course Name of lecturer

Astrophysics M. Hack and N. Dallaporta

Collision Theory L. Fonda

Dispersion Relations G. Furlan

Elementary Particles I G. Furlan and C. Cemigoi

Elementary Particles II D. Amati

Field Theory G.C. Ghirardi

Group Theory R. Rjczka

Plasma Physics C. Kennel and H. Berk

Solid State Physics R. Fieschi

Theory of Nuclear Reactions G.C. Ghirardi and A. Rimini

Experimental Techniques of G. P Irani Nuclear Physics

Neutron and Reactor Physics G. Pauli

4. DISSEMINATION OF SCIENTIFIC INFORMATION

All the preprints of the Centre are sent to institutes or to individuals from twenty developing countries. A preprint registry including a list of preprints on theoretical elementary particle physics received at the Centre from other research groups (with an abstract and classified according to the subject) is published fortnightly and sent to all addresses on the mailing list. The purpose of this registry is to make physicists working in isolated centres aware of current work in theoretical physics. III. ADMINISTRATIVE MATTERS, STAFF MEMBERS AND PUBLICATIONS

1. FINANCE

The budget

For the financial period 1 January to 31 December 1966 the International Centre for Theoretical Physics had at its disposal funds totalling US $ 472 261. Of this an amount of $ 278 000 represented the Italian Government's contribution for that financial year; $ 110 000 were contributions from the Agency (a sum of $ 7 5 000 from the Regular Budget and $ 35 000 from the Operating Fund); $ 3 500 represent other income and $ 80 761 were carried forward from the 1965 budget. An amount of $ 46 713 will be carried forward to cover 1967 operation costs. This sum is a balance of $ 44 645 (being the difference between total resources of $ 472 261 and incurred expenditure and obligations amounting to $ 427 616) and $ 2 068 savings on liquidations of prior years' obligations.

Expenditure

The expenditure and obligations during 1966 were as follows: US $

Salaries and other staff costs 265 680 Fellowships 52 817 Scientific documents 11 320 Library 13 655 Scientific and technical services 6 000 Duty travel of staff 6 922 Conferences and Seminars 25 730 Common services and supplies 42 561 Hospitality 2 931

TOTAL 427 616

2. SCIENTIFIC STAFF

Ninety-six visiting physicists andFtellows from thirty-one countries have worked at the Centre for periods ranging from a few weeks to twelve months (fifty-seven in the elementary particles group and thirty-nine in the plasma physics group). Thirty-three of them were not financed by the Centre. The names and nationalities of the staff are mentioned below.

118 TRIESTE 119

Twenty-eight guest lecturers were invited to deliver seminars in the framework of the weekly seminar programme.

Director: Abdus Salam (Pakistan) Deputy Director: P. Budini (Italy)

2. 1. Elementary particle physics

D. A. Akyeampong (Ghana) J. Niederle (Czechoslovakia) R. Anderson (USA) R. Oehme (Federal Republic of Germany) A. Bartl (Austria) S. Okubo (Japan) A. Bohm (Federal Republic of Germany) P. Pajas (Czechoslovakia) S.K. Bose (India) T. Pradhan (India) J. Boyce (UK) R. Rjczka (Poland) G. Cocho (Mexico) T. Regge (Italy) C. L. Cook (New Zealand) E. Remiddi (Italy) R. Delbourgo (UK) B. Renner (Federal Republic of Germany) H.D. Doebner (Federal Republic of Germany) R.J. Rivers (UK) N. T. Evans (New Zealand) C. Rossetti (Italy) Fayyazuddin (Pakistan) H. Ruegg (Switzerland) G. Fernando (Ceylon) W. Ruhl (Federal Republic of Germany) J. Fischer (Czechoslovakia) I. Saavedra (Chile) C. Fronsdal (Norway) M. Sachs (USA) S. Fubini (Italy) T.S. Santhanam (India) A. Giovannini (Italy) I. S. Satsunkevich (Byelorussian SSR) F. Hadjioiannou (Greece) К. T. Shah (Pakistan) Y. Hara (Japan) J. Strathdee (USA) Harun-ar-Rashid (Pakistan) K.S. Tausk (Brazil) M. Kawaguchi (Japan) J.C. Taylor (UK) M. P. Khanna (India) W. Thirring (Austria) C.P. Korthals Altes (Netherlands) I. Todorov (Bulgaria) W. Królikowski (Poland) A. Vaidya (India) N. Limic (Yugoslavia) J.E. Wess (Austria) C.A. López (Chile) R. White (USA) V.M. Massida (Italy/Argentina) P. Williams (UK) P. Narayanaswamy (India) A.H. Zimerman (Brazil) Y. Nè'eman (Israel)

2. 2. Plasma physics group

Directors: M.N. Rosenbluth (USA) R.Z. Sagdeev (USSR)

O. de Barbieri (Italy) E. Frieman (USA) H. L. Ben Othman (Tunisia) H.P. Furth (USA) H.L. Berk (USA) A. A. Galeev (USSR) B. Bertotti (Italy) K. W. Gentle (USA) D. Book (USA) J.M. Greene (USA) A. Cavaliere (Italy) Z. M. Hassan (UAR) R. Chodura (Federal Republic of Germany) C. W. Horton (USA) B. Coppi (Italy) J.L. Johnson (USA) W.E. Drummond (USA) C.F. Kennel (USA) F. Engelmann (Federal Republic of Germany) Kim in Kyu (Korea) 120 TRIESTE

К. Kitao (Japan) A. Sestero (Italy) N. A. Krall (USA) A. Skorupski (Poland) G. Laval (France) B.I. Sorour (UAR) B. Lehnert (Sweden) T. E. Stringer (UK) A. Nocentini (Italy) R.N. Sudan (India/USA) C. Oberman (USA) J.B. Taylor (UK) T. M. O'Neil (USA) Wei Chau-Chin (China) R. Pellat (France) H. V. Wong (Jamaica) D. Pfirsch (Federal Republic of Germany) N.J. Zabuski (USA) A. Sabry (UAR)

3. SCIENTIFIC DOCUMENTS

3. 1. Publications and preprints2 issued in 1966

BERK, H.L., SUDAN, R.N., ROSENBLUTH, M.N., Plasma wave propagation in hot inhomogeneous plasma. Physics Fluids 9 (1966) 8; IC/66/1.

R^CZKA, R., LIMIC, N., NŒDERLE, J., Discrete degenerate representations of non-compact rotation groups, J. Math. Phys. (in press); IC/66/2.

NARAYANASWAMY, P., PRADHAN, T., SANTHANAM, T.S., A new approach to algebra of current operators; IC/66/3.

KENNEL, C. F., THORNE, R. M., Unstable growth of unducted whistlers propagating at an angle to the geo- magnetic field; IC/66/4.

ABDUS SALAM, STRATHDEE, J., A relativistic U(6,6) theory, Phys. Rev. 148 (1966) 1352; IC/66/5.

BISIACCHI, G., BUD INI, P., Maximal degenerate systems dynamics, Nuovo Cim. 44 (1966) 418; IC/66/6.

KRÓUKOWSK1, W., Difference between sources and charges; IC/66/7.

KRÔLIKOWSKI, W., Remarks about the Fubini-Furlan method; IC/66/8.

CAVALIERE, A., ENGELMANN, P., Hydromagnetic waves: laminar disturbances of finite amplitudes; 1С/66/9.

OKUBO, S., Inconsistency of canonical commutation relations among current densities, Nuovo Cim. 44 (1966)1015; IC/66/10.

LOPEZ, C. A., SAAVEDRA, I., Completeness and dispersion relations in the complex angular momentum plane, Nucl. Phys. 81 (1966) 65; IC/66/11.

MAURIN, K., General eigenfunction expansions and group representations (Lecture notes); IC/66/12.

FURLAN, G., JENGO, R., REMIDDI, E., Evaluation of the Nj3N weak coupling constants by means of current algebra, Physics Lett. 20 (1966) 679; IC/66/13.

OKUBO, S., Impossibility of having the exact U(6) group based upon algebra of currents, Nuovo Cim. 42 (1966) 1029; 1С/66/14.

2 1С = Preprints of the International Centre for Theoretical Physics, Trieste. TRIESTE 121

KROLIKOWSKI, W., Partial conservation of tensor current and electromagnetic form factors, Nuovo Cim. 44 (1966) 745; 1С/66/15.

R^CZKA, R., FISCHER, J. , Discrete degenerate representations of non-compact unitary groups, Commun. Math. Phys. 3 (1966) 233; IC/66/16.

KENNEL, C.F. f Velocity space diffusion from weak plasma turbulence in a strong magnetic field; IC/66/17.

LIMIC, N., NIEDERLE, J., R^CZKA, R., Continuous degenerate representations of non-compact rotation groups, J. Math. Phys. (in press); IC/66/18.

BISIACCHI, G., FRONSDAL, C,, Attempts at understanding the mass spectra of elementary particles, Proc. V. Internationale Universitâtswochen fur Kernphysik, Schladmingj IC/66/19.

FRONSDAL, C. , WHITE, R. , The strong vertex according to SL(6,C), Phys. Rev. (in press); IC/66/20.

KENNEL, C.F., WONG, H. V., Resonant plasma wave growth in a uniform magnetic field. High ion 6 pitch- angle instability, Phys. Rev. Lett. 17 (1966) 245; 1C/66/21.

BOSE, S.K., BISWAS, S.N., Relation between leptonic and non-leptonic К meson decays and current algebras, Nuovo Cim. 43 (1966) 1182; IC/66/22.

AKYEAMPONG, D. A., On the representations and coupling of the U(6) tower, Nuovo Cim. 45 (1966) 712; IC/66/23.

COPPI, B., ROSENBLUTH, M.N., SAGDEEV, R.Z., Instabilities due to temperature gradients in complex magnetic field configurations; IC/66/24.

KRÓLIKOWSKI, W., Partial conservation of tensor current arid electromagnetic decays; 1С/66/25.

SANTHANAM, T. S., P-wave non-leptonic decays of hyperons in SU(6) and representation mixing, Phys. Lett. 21 (1966) 234; IC/66/26.

COCHO, G., FRONSDAL, С., HARUN-AR-RASHID, WHITE, R., Electric charge form factor according toSL(6,C), Phys. Rev. Lett.17 (1966) 275; IC/66/27.

KHANNA, M.P., OKUBO, S., Are quarks fractionally or integrally charged! Ann. Phys. (New York) 40 (1966) 153; 1С/ 66/28.

SAAVEDRA, I. , Completeness, unitarity and dispersion relations in potential scattering, Nucl. Phys. (in press); 1С/66/29.

BOYCE, J.F., The relation of the 0(2,1) partial wave expansion to the Regge representation; IC/66/30.

BOSE, S.K., ZIMERMAN, A.H., Equal time commutators and i) -»Стгdecays, Nuovo Cim. 43 (1966) 1165; IC/66/31.

GALEEV, A. A., Gravitational instability of a collisionless plasma in a toroidal magnetic trap; IC/66/32.

SANTHANAM, T.S., Representation mixing in static SU(6) and the relation between and (D/F)AX; IC/66/33.

KRÓLIKOWSKI, W., Universal coupling of vector mesons revisited, Nuovo Cim. (in press); IC/66/34.

COCHO, G., WHITE, R., Mass formulae and U(6) ® U(6) mixing-, IC/66/35. 122 TRIESTE

FISCHER, J. , R£CZKA, R., Degenerate representations of non-compact unitary groups - II, Commun. Math. Phys. (in press) ; IC/66/36.

RIVERS, R.J., Particle mixing and Jp = 2+meson decays; IC/66/37.

TAYLOR, J.C., Chiral group with a new use of its representations; IC/66/38.

OEHME, R., Saturation of U(3) &> U(3) algebras at infinite momentum and finite momentum transfer, Nuovo Cim. 45 (1966) 666; 1С/66/39.

OKUBO, S., A high-energy theorem by algebra of currents, Nuovo Cim. 44 (1966) 276; IC/66/40.

DELBOURGO, R., ABDUS SALAM, STRATHDEE, J., On the dynamical origin of SU(6), Phys. Lett. 21 (1966) 455; 1С/66/41.

NARAYANASWAMI, P., PRADHAN, T., Cabibbo angle as a renormalization effect; IC/66/42.

COCHO, G., HARUN-AR-RASHID, The algebra of currents and the meson form factors. Prog, theor. Phys. (in press); IC/66/43.

HARA, Y., Current X Current interaction and | Д1| = i rule; IC/66/44.

SKORUPSKI, A., WKB approximation in the complex plane and applications to plasma theory; IC/66/45.

COCHO, G. , HARUN-AR-RASHID, Regge pole behaviour in an SL(2,c) model field theory, Nuovo Cim. (in press); IC/66/46.

BOSE, S.K., Generalized nonet representation of SW(3) and its applications, Phys. Rev. 150 (1966) 1231; 1С/66/48.

OEHME, R., Saturation of the SU(3) algebra of current densities, Phys. Lett. 21 (1966) 567; IC/66/49.

RIVERS, R.J., Renormalised w-® mixing angle and Jp = 1" meson decays, Phys. Rev. (in press); IC/66/50.

FRONSDAL, C., The representations of SL(n,C); IC/66/51.

KRÓLIKOWSKI, W., Cabibbo angle and partial conservation of axial current; IC/66/52.

STOYANOV, D. T. , TODOROV, I. T., Dynamical symmetry and hadron mass-spectrum ; IC/66/53.

HARUN-AR-RASHID, Photo-production of vector mesons from nucléons, Nucl. Phys. (in press); IC/66/54.

COPPI, B. , LAVAL, G. , PELLAT, R., ROSENBLUTH, M.N., Microinstabilities in configurations with varying curvature (and V" < 0), to be published; IC/66/55.

SABRY, A.A., Equation of state of real gases; IC/66/56.

HARA, Y., Non-leptonic decays of ii', Phys. Rev. 150 (1966) 1175; IC/66/57.

KENNEL, C.F., WONG, H. V., Resonantly unstable off-angle hydromagnetic waves, J. Plasma Physics (in press); IC/66/58.

PRADHAN, T., Cabibbo angle and the ninth baryon; IC/66/59. TRIESTE 123

DELBOURGO, R., ABDUS SALAM, STRATHDEE, J., Bound state equation for quark-antiquark system, Nuovo Cim. (in press); IC/66/60.

HA RUN -AR-RASHID, KAWAGUCHI, M., Absorption correction in high-energy photo-production of pions, Nuovo Cim. (Letters) 44 (1966) 1252; IC/66/61.

LIMIC, N., NIEDERLE, J., R^CZKA, R., Eigenfunction expansions associated with the second order in- variant operator on hyperboloids and cones, J. Math. Phys. (in press); IC/66/62.

COPPI, в., Geodesic curvature in closed plasma configurations, Nucl. Fusion 6 4 (1966) 293-96; IC/66/63.

SAGDEEV, R.Z., GALEEV, A. A., Lectures on the non-linear theory of plasma; IC/66/64.

OKUBO, S., Tests of models of elementary particles, Suppl. to Prog, theor. Phys. 1966 (in press); IC/66/65.

BOSE, S.K., HARA, Y., Meson-baryon coupling constants in broken SU(3) and the algebra of currents, Phys. Rev. Lett. 17 (1966) 409; IC/66/66.

BERK, H. L., BOOK, D. L., PFIRSCH, D., Convergence of the Bremmer series for the spatially inhomogeneous Helmholz equation; IC/66/67.

KENNEL, C.F., SAGDEEV, R. Z., Collisionless shock waves in high 6 plasmas. Parti; IC/66/68.

ОЕНМЕ, R., Electromagnetic form factors from the locality of current densities, Phys. Lett. 22 (1966) 206; 1С/66/69.

KRÓLIKOWSKI, W., Partial conservation of tensor currents and Pauli-interaction, Nucl. Phys. (in press); 1С/66/70.

TODOROV, I.T., Discrete series of hermitian representations of the Lie algebra of U(p,q) (Lecture notes); 1С/66/71.

SUDAN, R.N., ROSENBLUTH, M.N., CAVALIERE, A., Non-linear interaction of helicons (whistlers) in inhomogeneous media; IC/66/72.

FAYYAZUDDIN, RIAZUDDIN, Algebra of currents and p-wave non-leptonic hyperon decays, Nuovo Cim. (in press); 1С/66/73.

BARTL, A., KORTHALS ALTES, C.P., Calculation of the form factors in K{3 decay; IC/66/74.

COPPI, В., Localized mode due to impurity density gradient (in press); IC/66/75.

AKYEAMPONG, D.A., The quark model and elastic baryon-baryon scattering; IC/66/76.

PAJAS, P., R^CZKA, R., Degenerate representations of the symplectic groups. Parti; IC/66/77.

ROSENBLUTH, M.N., SAGDEEV, R. Z., TAYLOR, J. В., ZASLAVSKI, G. M., On the destruction of magnetic surfaces due to the irregularities of magnetic field, Nucl. Fusion (in press); 1С/66/78.

COPPI, В., FURTH, H. P., ROSENBLUTH, M.N., SAGDEEV, R. Z., A drift instability due to impurity ions, Phys. Rev. Lett. 17 (1966) 377; IC/66/79.

RIVERS, R.J., A quark model derivation of meson-baryon coupling constant relations, Phys. Lett. 22 (1966) 514; IC/66/80. 124 TRIESTE

SACHS, M., On factorization of Einstein's formalisms into a pair of quarternion field equations, Nuovo Cim. (in press); IC/66/81.

GALEEV, A.A., A new approach to plasma turbulence ; IC/66/82.

GALEEV, A. A., KENNEL, C. F., SAGDEEV, R. Z., Electron heating by ion sound turbulence (in press). 1С/66/83.

COCHO, G., FRONSDAL, С., HARUN-AR-RASHID, WHITE, R., Hadron form factors according to SL(6,C); IC/66/84.

DELBOURGO, R., ABDUS SALAM, STRATHDEE, J., Multiple field relations, Phys. Lett. 22 (1966) 680; 1С/ 66/85.

AMATI, D., JENGO, R., REMIDDI, E., A new family of sum rules from current algebra, Phys. Lett. 22 (1966) 674; 1С/66/86. —

BISIACCHI, G., BDDINI, P., On the algebraic formulation of dynamical models, Nuovo Cim. (in press); 1С/66/87.

KENNEL, C.F., SAGDEEV, R.Z., Collisionless shock waves in high 6 plasmas. Part П; IC/66/88.

FRONSDAL, C. , HARUN-AR-RASHID, Matrix elements of operators of class 1 representations of SL(n,C); IC/66/89.

KENNEL, C.F., ENGELMANN, F. , Velocity space diffusion from weak plasma turbulence in a magnetic field, Physics Fluids (in press); IC/66/90.

BERK, H.L., GALEEV, A. A., Velocity space instabilities in a toroidal geometry; IC/66/91.

GALEEV, A. A., Quasi-linear theory of the loss-cone instability, J. Plasma Physics (in press); IC/66/92.

BERK, H.L. , HORTON, C.W. , ROSENBLUTH, M. N. , SUDAN, R.N., Plasma wave reflection in slowly varying media; 1С/66/93.

SESTERO, A., Self-consistent description of a warm stationary plasma in a uniformly sheared magnetic field; IC/66/94.

PFIRSCH, D., Application of Hamilton-Jacobi-theory to Vlasov's equation; IC/66/95.

SCHWABL, F., THIRRING, W., WESS, J., A refined solution of two-dimensional model theories; IC/66/96.

DOEBNER, H. D., MELSHEIMER, О., On representations of Lie algebras with unbounded generators. Part I-, 1С/66/97.

DRUMMOND, W.E., GENTLE, K.W., The effect of magnetic shear on plasma instabilities; IC/66/98.

NIEDERLE, J. , Decompositions of discrete most degenerate representations of SO0(p,q) with respect to re-

presentations of SO0 (p,q-l) or SO0(p - 1,2); IC/66/99.

GALEEV, A.A., SAGDEEV, R. Z., WONG, H.V., Influence of static, radial electric fields on trapped particle instabilities in toroidal systems; IC/66/100.

FISCHER, J., R^CZKA, R., Infinite-dimenSional irreducible representations of Lie algebras of compact unitary groups; IC/66/101. TRIESTE 125

ANDERSON, R. L., FISCHER, J., R^CZKA, R., Coupling problem for U(p,q) "ladder" representations. Parti; IC/66/102.

KRALL, N.A., On the quasi-linear limit of a drift instability and its relation to auroral bombardment; IC/66/103.

3. 2. Library and scientific information

The library has nearly 3500 books covering the main fields of theoretical physics and mathematics and subscribes to nearly 90 periodicals. 200 preprints are received every month from other institutions. The Scientific Information Office released 124 preprints in 1965-1966 (in section 3. 1 are listed the preprints starting with 1 January 1966) of which 32 were on plasma physics (sent to 300 addresses) and 92 were on elementary particle physics (sent to 650 addresses). This office also issues the fortnightly preprint registry for elementary particle physics containing approximately 60 titles (with abstracts) of preprints received at the Centre. The Proceedings of the Seminar on High-Energy Physics and Elementary Par- ticles held in May-June 1965 were published in December 1965. APPENDIX

STATISTICAL DIGEST

(For the academic year 1965/66)

I. Scientific staff

Number of physicists having worked at the Centre: Visiting scientists 42 + (24)3 Fellows 19 + (13) Guest lecturers 23 + ( 5) Associate members ( 2)

Total 84 + (44)

II. Participation in ICTP meetings

Seminar on high-energy physics: Number of lecturers 43 Number of participants 78 (not including the staff of the Centre present at the time)

III. Nationalities represented 37

IV. Developing countries represented 18

Participation of visiting scientists, Associates and Fellows (man/month) 202.5

V. Advanced School of Physics

Number of Agency Fellows who attended in 1965/66 (10 from developing countries) 15

3 Figures in brackets show the number of scientists who were already present during the previous year.

126 TRIESTE 127

VI. Library

Number of books 3500 Number of scientific periodicals 90 Preprints and reports received per month from other institutions 200

VII. Scientific information

Published books Proceedings of the Seminar on Plasma Physics (640 pages)

Proceedings of the Seminar on High-Energy Physics and Elementary Particles (1000 pages)

Proceedings of the International Course on Nuclear Physics (approximately 800 pages, in press)

Preprint registry Issued fortnightly since January 1966 (60 titles with abstracts)

Mailing lists Elementary particle physics 650 Plasma physics 300 Nuclear physics 200

THE MIDDLE EASTERN REGIONAL RADIOISOTOPE CENTRE FOR THE ARAB COUNTRIES, CAIRO

I. INTRODUCTION

During its fourth year, the Centre continued its activities according to the programme adopted by its Governing Body. The present fourth annual report gives an account on the work accomplished and the results achieved in 1966. The Centre's Governing Body consists of: (a) one representative of the host state (United Arab Republic) ; (b) three representatives of the participating Arab States to be elected by them; and (c) the Director General of the International Atomic Energy Agency or his representative. In 1966 the three elected members were: Algeria, Iraq and Kuwait. Observers from the participating states attended the meetings of the Governing Body. During 1966 the Governing Body held two sessions at which it adopted 32 resolutions. Among them: the approval of the Centre's accounts for the fiscal year 1965; the approval of the annual report for 1965; the adoption of the scientific programme for 1967; the adoption of the budget for 1967; the organization of a scientific symposium to be held in 1968 on the use of radioisotopes in some agricultural sciences; the publication of a scientific maga- zine 'Isotope and Radiation Research'; the development of the Centre and the promotion of its activities after 1968; the adoption of certain rules concerning research projects undertaken in the participating states; and the ap- pointment of Dr. Rudolf Hôfer as a technical adviser for the Centre.

131 II. THE SCIENTIFIC PROGRAMME OF THE CENTRE

The adopted scientific programme of the Centre is: (a) training specialists in the application of radioisotopes in science, industry, agriculture and medicine; and (b) conducting research using radioisotope techniques in hydrology, agriculture, entomology and medicine.

1. TRAINING

Two courses were organized by the Centre in 1966. The first special training course in medicine was held from 16 April to 23 June 1966, and the second special training course in protection and nuclear instrumentation was held from 10 September to 3 November 1966. The first special training course in medicine was divided into two periods: an initial period of eight weeks devoted to lectures and experimental work, and a second period of two weeks of practical training in the Cairo University hospital, the Ain Shams University hospital, the Alexandria Uni- versity hospital and the Institute of Research for Tropical Medicine. The syllabus of this course is laid down in the 1964 Annual Report of the Centre (Sc. REP/4). From a total of 22 applicants nominated by 5 countries for the medical course, 18 candidates were selected, 17 of whom attended the course regularly. The second special training course in protection and nuclear instrumentation was also divided into two periods: the first period of six weeks devoted mainly to lectures and experimental work on radiation protection and radiation protection instrumentation, and a second period of two weeks devoted to basic electronic circuits and some nuclear instrumentation. From a total of 25 applicants nominated by 6 countries for the course in protection and nuclear instrumentation, 21 candidates were selected, 15 of whom attended the course regularly. In the two courses lecturing, instructing and supervising of the experiments were performed by members of the staff of the Cairo, Alexandria and Ain Shams Universities, of the staff of the Atomic Energy Establishment (Inshas), the staff of the Centre and by four visiting professors (three from the Agency and one from the United Kingdom. The interest of the trainees in the subject and their attendance at the course were satisfactory. According to the observations and reports of the teaching staff, all were eager to perform the practical work in the best possible way and to profit as much as possible from the course. The number of applications considered (N), of candidates selected (S) and of the trainees actually attending the course (A) from the different countries in the two courses is shown in Table I.

132 CAIRO 133

TABLE I. ATTENDANCE AT COURSES

COUNTRY

Course Date Jorda n Suda n Ira q Tunisi a Algeri a Saud i Arabi a Syri a UA R Kuwai t Morocc o Yeme n Lebano n Liby a Tota l 1 Othe r countrie s

Medicine from 16/4/66 N 2 6 1 12 1 22

to 23/6/66 S - -- 2 6 1 8 - 1 --- - 18 A 2 6 - 8 1 17

Protection from 10/9/66 N 2 1 3 2 1 16 25 and nuclear to 3/11/66 S 2 -- 1 3 2 1 12 21

instrumentation A 2 1 1 • 11 - 15

2. RESEARCH

2.1. Hydrology

2.1.1. Investigation of the Wadi El-Natrun aquifer

The investigation of the Wadi El-Natrun aquifer including determination of effective porosity, permeability, storage coefficient and transmissibility using different radioisotopes (IAEA Research Contract No. 302) was completed and the details of the work and the results obtained are included in a report submitted to the Agency. The projects aimed at were: (a) Investigation of groundwater radial flow using radioactive tracers; and (b) Determination of the effective porosity using a model basin.

(a) Investigation of groundwater radial flow using radioactive tracers

Field experiments had been made to study the effective porosity of the groundwater aquifer, injecting 131I simultaneously with зн, as a reference, at different depths, aiming at examining the influence of the depth of injection of the radioisotopes on the values obtained for the effective porosity of the aquifer under pumping conditions. A pumped well, fully penetrating a homogeneous sandy aquifer, was chosen. Three runs were undertaken, injecting the radioisotopes in an observation well 10 metres away, at three different levels. An additional run was made injecting !3ll at the three depths simultaneously. In each run, the activity of the outflowing water was followed until it reached the background level. 134 CAIRO

The results indicate that the values obtained for the effective porosity of groundwater aquifer using tracers are not dependent on the depth of injection of the tracer. This conclusion holds for radial flow, in homogeneous aquifers, between the observation well and the pumped well. The percentage recovery of the injected activity was calculated. ~ The experiments were undertaken in the Wadi El-Natrun area in the western desert of the UAR. The value of the effective porosity for the investigated locality was found to be 0. 09.

(b) Determination of the effective porosity using a model basin

Accurate determination of the effective porosity of underground water aquifers is important for the proper exploitation of water. For this reason, a model basin was constructed to examine the technique applied by the Centre for the determination of the effective porosity using radioactive tracers. The basin is 3 m in diameter and 1.40 m deep. The bottom 1 m of the basin is filled with sand, surrounded by a 0.15-m layer of pebbles and charging tubes. The sand is screened from the pebbles by a double fine mesh. A 0. 30-m layer of impermeable clay is placed above the sand and pebbles for confinement. The basin is provided with a central pumping well and four piezometers placed 1. 24, 0. 92, 0. 59 and 0. 30 m away from the pumping well. An electric pump and a flow meter are fitted to the central well. Four runs at different pumping rates were undertaken on each of the piezometers at 0.59, 0.92 and 1.24 m. Iodine-131 was used as a tracer. The results were consistent and in agreement with the values obtained directly. This confirms the validity of the technique as applied several times by the Centre.

2.1.2. Hydrochemical investigations and dating of underground water in the UAR, Libya and the Sudan

As is stated in previous year's Annual Report (for 1965), the aim of this project is to investigate the groundwater resources in the part of the Great Sahara that covers the western desert of the UAR, the Libyan desert, and the desert of northern Sudan. During 1966, more samples of groundwater were collected from the UAR (New Valley) and Libya. Most of these samples were analysed for major constituents, and activation analyses have been undertaken for trace elements. Dating of some samples has been carried out. A report on underground water field investigations carried out in Kuwait during 1966 was submitted to the authorities in Kuwait and the Governing Body of the Centre. The work had been continued according to the programme of work laid down for this project.

Hydrology Team

Prof. Dr. Ismail B. Hazzaa, Dr. Mohamed S. Youssef, CAIRO 135

Dr. Raafat K. Girgis, Dr. Eng. Kamal F. Saad, Dr. Abdel-Rassoul A. Abdel-Rassoul, Eng. Kamal H. Hefny, Eng. Abdallah El-Sharhan (Kuwait), Eng. Nabih S. Akhras (Kuwait), Mr. Mahmoud M. Mahdi, Eng. Youssef К. Shuhaiber (Kuwait), Mr. Abdel-Fattah Eskengi (Libya), Mr. Fayez M. Swailem, Mr. Ad el A. Bakr, Mr. Saad M. Refaai, and Mr. Nader Kh. Ghattas.

2.2. Agriculture

2.2.1. Research work within the framework of a co-ordinated programme on the application of radiation techniques in water-use efficiency studies (IAEA Research Contract No. 310)

After the assembly of the lysimeters as reported previously,1 the two lysimeters were set in place after all tests for leakage from the system had been carried out and had proved successful. The soil was transferred to the lysimeters in the same order as the original sequence of layers. The moisture in the layers was determined to estimate dry weight and total moisture in profile. The readings in the manometer tubes against increasing weight of soil in the lysimeters indicate that, in both lysimeters, each ton raises the water by 31.1 cm. Maize was sown in the lysimeters and surrounding experimental area on 24 July 1966, and irrigation was started on the same day. The regime of fertilizers and irrigation in the two treatments was executed following the instructions given for the co-ordinated Research Pro- gramme of the Joint FAO/IAEA division. The neutron probe was calibrated. Measurements of moisture depletion in the plots and lysimeters, clima- tological conditions, and plant growth were and are still being carried out regularly. Five irrigation applications took place up to the time of writing this report. Crop maturity and yield measurements are expected to be completed by the first week of November. A break-down took place in the bolsters of lysimeter No. 2. Repairs are not possible now because of the damage that may occur to adjacent plots if the lysimeter is lifted up. Readings of moisture by the neutron probe and other observations are being continued. A copy of the results will be issued in time. (26 October 1966).

1 INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No.55. IAEA, Vienna (1966) 145. 136 CAIRO

2. 2. 2. Nitrogen and phosphorus fertilization of wheat using labelled fertilizers

The objectives are: (a) To study the effect of time of nitrogen application in different forms on its utilization by wheat, and (b) To study the interaction between nitrogen fertilizer forms and phosphorus utilization by wheat. The project is composed of two main experiments: the first one deals with the time of application of different nitrogen fertilizer forms using 15N, and the second deals with the effect of forms and quantity of nitrogen fertilizers on phosphorus utilization using 32P. Field and pot experiments of wheat fertilization using 15N were planned to be carried out at four localities. The second experiment using 32P was carried out in the Sudan (Khartoum University) and in four different localities in the UAR, i.e. Giza (Cairo Uni- versity), Shoubra (Ain Shams University), Alexandria (Alexandria University) and Wadi El-Natrun. These localities were chosen because of their differences in soil texture and climatic conditions. The prepared labelled superphosphate was applied and planting was done in December 1965. Three quarters of the nitrogenous fertilizers were added at tillering (end of January 1966). Plant samples were taken at three times; the first and the second at 3 weeks after the first and second application of nitrogenous fertilizers, respectively, and the third at harvesting. The grain yields of each experiment were recorded and statistically analysed. Samples of the plants taken at different stages of growth were analysed for 32P and 31P and the uptake of soil and fertilizer phosphorus by the plants was determined. This experiment is being repeated in 1966-67 at two localities using 32P. The interpretation of results of these 1966-67 experiments will be carried out together with those of the experiments of 1965-66.

2. 2. 3. Other research in agriculture

To overcome difficulties encountered in the determination of the soil exchangeable sodium using the classical methods, the isotopic dilution method with radioactive 22Na suggested by Bower, Hatcher and Babcock was studied. This method offers a means for the direct estimation of the variation in the exchangeable sodium with the variation in the soil-water ratios. In carrying out the estimation of exchangeable sodium at soil-water ratios 1:5, 1 :10 and 1 : 20, inconsistent results were obtained especially in the case of highly saline soils and harrow soil-water ratio. It seems that at high concentration of Na+ in the solution phase of the soil-solution system, the distribution of 22Na between the solution and the soil surface did not reach equilibrium after shaking for 2 hours. Two means were attempted to overcome this difficulty: (a) by increasing the time of shaking to allow equilibrium to take place, (b) by increasing the amount of radioactive 22Na added to the system. The results showed that shaking should be done for 6 hours in the case of highly saline soils and narrow soil-water ratios. Increasing the radioactive 22Na improved the results but was less effective than increasing the time of shaking. CAIRO 137

A critical study of the Schoonover method for the determination of the gypsum requirements for reclaiming saline alkali soils was carried out. As the exchangeable sodium is positively correlated with the gypsum requirement values, a mathematical relationship between the two values was tenta- tively established. Using 22Na renders the determination of the exchangeable sodium easy and simple. Hence it could be used as an indication for the soil gypsum requirement. The work will be prepared for publication. A study on soil phosphorus evaluation as estimated by L- and K-values was carried out. The results indicate that the capacity factor alone as indicated by the L-value is not sufficient for characterizing soil phosphorus. The total 'P' uptake by the plants correlates fairly well with the K-value, which is a constant related to the bonding energy of the soil for phosphorus. Hence, obtaining the L- and K-values of a soil will give a more complete picture of soil phosphorus and can be taken as a criterion of soil phosphorus evaluation in various soils, whatever the range of soil properties. The study of the dependence of photosynthetic yields on the water and mineral supply was continued. The effect of a deficiency of some minerals on respiration rate and photosynthetic activity using Zea mays seedlings was investigated. Two radioisotopes, 14C and 32P, were used in the study. This double-labelling procedure was done to resolve phosphorylated carbohydrates from other photosynthates. The work revealed that both sugar and amino acids are involved in the photosynthesis process. However, due to the use of different conditions of mineral deficiency, variable data concerning the separated products were obtainedi

Agriculture Team

Prof. Dr. Abdalla Zein El-Abedine, Prof. Dr. Mohammed A. Abdel Salam, Dr. Abdel-Moneim Balba, Dr. Hassan M. Hassan, Dr. Fayez Madi, Dr. Mohammed M. Abdalla, Dr. Kamal A. Agabawi (Sudan), Dr. Faisal El Khalisi (Iraq), Dr. Naguib F. Kheir, Dr. Yehia H. El-Shafiey, Miss Camilia M. Sobhy, Mr. Hassan Bariouni, Mr. Mohammed E. Alninna and Mr. Shafik I. Abdel-Aal.

2.3. Entomology

Studies on the eradication of Anopheles pharoensis Theo. by the sterile- male technique using 60Co radiation have been continued. Field studies on the population dynamics of A. pharoensis which started in December 1964 in a semi-isolated area in the Fayoum Province, 100 km south-west of Cairo, are still in progress. Studies on the flight range and dispersion of this ano- 138 CAIRO

pheline species are planned. Also the determination of the population density of A_. pharoensis in the experimental area in Fayoum before the release of sterilized males will be executed. The field study on the dispersion and flight range of Anopheles sergenti Theo., using radioisotopes as markers, which was undertaken in the Siwa Oasis from 18 September to 30 October 1965 was issued by the WorldHealth Organization as a scientific document (WHO/Mal/ 66. 568, WHO/VC/66. 209). The paper on this study was accepted for publication in the Bulletin of the World Health Organization on 21 November 1966. Work is continuing with some radioisotopes other than those used in the previous period to label grasshoppers, and for metabolic studies using isotopically labelled compounds. Studies on the ecological factors affecting the control of the Medi- terranean fruit fly Ceratitis capitata Wied. by the sterile-male technique in the UAR are in progress. The project financed by the IAEA under Research Contract No. 408 started in June 1966. After several trials in different areas in the UAR, an experimental field site was chosen in the Wadi El-Natrun, about 100 km north-west of Cairo. A successful colony of Ceratitis capitata has been raised and main- tained under laboratory conditions using up-to-date techniques introduced by Ahmed S. Abdel-Aziz following training in the Entomology Labora- tory of the IAEA at Seibersdorf, Austria, in June 1966. Two breeding rooms at the Department of Entomology, Faculty of Science, Cairo Univer- sity, were provided with cages, trays, egg-collecting devices and other necessary equipment. The temperature is kept constant at about 25° С and the relative humidity at about 70%. Adult flies are reared in cages measuring 60 cmX40 cmX 40 cm, with one side covered with muslin through which the females lay their eggs. Eggs are collected daily and cultivated in carrot medium. A weekly production of about 100 000 flies is now established and a greater number can be easily obtainedif required. In the Wadi El-Natrun area, both wild and cultivated plants are sur- veyed for identification purposes. Samples of different fruits are collected and examined for the presence of the Mediterranean fruit fly larvae. Samples of fruits are collected at intervals of 15 days to determine the rate of infestation throughout the year in the different hosts. An estimation of the size of the natural population of the Mediterranean fruit fly has not yet been started; also the study of the flight range of C. capitata is suspended, awaiting the determination of the sterilizing dose to avoid unnecessary infestation by release of normal flies. Since the gamma cell ordered for the Centre has not yet been received, gamma irradiation for the study of the sterilizing dose has been undertaken at Inshas, making use of the gamma cell of the UAR Atomic Energy Establishment located there. This work is still in progress.

Entomology Team

Prof. Dr. Mahmoud Hafez, Prof. Dr. Albert A. Abdel-Malek, CAIRO 139

Dr. Abdel-Azim O. Tantawy, Dr. Mohyee M. Ibrahim, Dr. Abdel-Fattah M. Wakid, Mr. Ahmed S. Abdel-Aziz, and Miss Laila M. El-Gazzar.

2.4. Medicine

2.4.1. Bilharziasis

(a) The haematological radioisotope studies in bilharziasis in the UAR are the subject of IAEA Research Contract No. 457. In conformity with the approved schedule of the contract work has started in September 1966. The study includes all the investigations necessary for the elucidation of all possible changes in erythrokinetics and ferrokinetics in the various stages of urinary and intestinal bilharziasis. The study of the blood volume changes in urinary bilharziasis and intestinal bilharziasis with hepatosplenomegaly was already accomplished and published. (b) Slapak's method for measuring the glomerular filtration rate is being assessed with regard to its accuracy, dependability and practicability, in both complicated and non-complicated cases of urinary bilharziasis, in comparison with the endogenous creatinine clearance method. It depends mainly on the measurement of the plasma clearance of radioactive vitamin B12 after pre-saturation with intravenously injected non-radioactive vitamin В12. Pre- liminary results are encouraging. Due to the low counts obtained, the pulse- height analyser must be applied as ordinary counting techniques are not suitable. (c) The Schilling test was used for the study of the intestinal absorption of vitamin В12 in both urinary and intestinal bilharziasis and in all intestinal parasitic infections prevalent in the UAR. No evidence of intestinal malabsorption could be observed in any of a large series of cases of intestinal parasitic infections even in the presence of severe anaemia. This confirms the concomitant finding that the associated anaemia is always hypo- chromic microcytic or normocytic, and the bone marrow is hyperplastic normoblastic. The relatively low level of urinary vitamin B12 excretion in some of the cases was found to be probably due to the adsorption of part of the dose by the excess mucus in the fasting gastric juice. Though the degree of adsorption was not assessed in this study, it was found that high urinary excretion levels were obtained on repetition of the test after preliminary gastric lavage with normal saline. In urinary bilharziasis the Schilling test was positive in all cases, indicating normal intestinal absorption of vitamin B12 . The relatively low urinary excretion levels observed in some of the complicated cases was found to be due to the low glomerular filtration rate as evidenced by Slapak's method of measuring the glomerular filtration rate with radiocyanocobalamin. In all stages of intestinal bilharziasis with hepatosplenomegaly the.Schilling test was positive which also confirms the other haematological findings that the bone marrow was hyperplastic normoblastic and the anaemia was of the dilution type due to hyper- 140 CAIRO plasmaemia. In some of the severely ascitic cases relatively low urinary excretion levels were observed probably due to the high dilution of the absorbed dose in the expanded extravascular pool, as evidenced by the detection of considerable concentrations of radiocyanocobalamin in the ascitic fluid in such cases, sometimes even higher than the concomitant blood levels. The latter phenomenon is now being under study by intravenous or intra- ascitic injection of radiocyanocobalamin and serial sampling of blood and ascitic fluid.

(d) Measurement of the hepatic blood flow by the use of colloidal radiogold was found to be more valid when calculated from the hepatic uptake method, due to the possible interference of bone-marrow uptake when the clearance over the head region was taken as a basis for calculation. The serial blood sampling technique was found to give a more rapid clearance rate than either of the above-mentioned methods due to its being an index of the total uptake by all possible sites, including the liver, the spleen, the marrow and other sites of reticulo-endothelial cells. The whole problem was one of the points which were critically discussed with R. Hôfer, the technical adviser to the Centre, during his visit in December 1966. Simul- taneous studies were made using the three above-mentioned methods. Care- ful shielding and collimation was used to avoid any interference in the in vivo measurements. These studies showed marked discrepancies especially in advanced cases of bilharzial hepatosplenomegaly. The results did not follow a definite trend. Thus further study of the problem was suggested to be carried out on a large number of patients with varying grades of the disease in order to clarify the possible interfering factors and their role, and to standardize the most suitable method for use in such cases.

(e) The study of the problem of assessment of protein-losing entero- pathy in intestinal bilharziasis with various grades of hepatosplenomegaly was hampered by the controversial data obtained with13II PVP and 1311 HSA. This was critically discussed with R. Hôfer who suggested the application of 51 Cr albumin. In collaboration with R. Hôfer the technique was studied with regard to standardization of the injected dose and collection and measurement of the radioactivity in the blood, the urine and the stool samples. The method of homogenization of stool samples and their counting technique was found to be very accurate and practical, being better than the plastic bag sampling. The method was then applied for the detailed study of six patients. A dose of 90-100 /лCi of 51Cr albumin was found to be satisfactory for each patient, and the data obtained were encouraging. The curious preliminary finding of definite intestinal protein loss in one case of bilharzial colonic polyposis and its absence in a case of bilharzial intestinal lymphangiectasis rendered it necessary to suggest the importance of conducting a special pro- tocol for the detailed study of the problem as it may lead to important findings. The whole matter and the future implications were discussed in detail with R. Hôfer.

(f) The trial of detection of collaterals by the intrasplenic injection of particulate and non-particulate radioisotopes did not give uniform or dè" pendable data in advanced cases of bilharzial hepatosplenomegaly. In many CAIRO 141 cases most of the radioactive material was captured for a considerable time in the splenic structure and thus interfered with the dependability of detection of the radioactivity by surface counts over the precordium and the liver despite efficient shielding and collimation. This was also proved by scanning. On discussing the matter with R.Hôfer and repeating the techniques frequently, especially with macroaggregated 1311 HSA, the contro- versy was definitely proved, despite the free flow of blood from the site of intrasplenic injection before injection. So the method was suggested to be further studied for modification or final devaluation.

2.4.2. Ancylostomiasis

The problem of red cell survival in ancylostomiasis is being understudy together with the effect of antiparasitic therapy or treatment of the anaemia or both. Up till now no final conclusions could be drawn. It is to be noted that ancylostomiasis in the UAR is caused by ancylostoma duodenale only.

2.4.3. Endemic goitre

Work on goitre in the UAR has been continued on sporadic cases from Cairo and endemic areas in the Libyan Desert using different techniques. An appraisal of the new radioisotope techniques developed in the past nine years in the Centre for the study of iodine metabolism was published. In this work, for the first time, pertechnetate as an indicator of thyroid function was used. Alternatively radioactive-labelled thyroid hormones have been prepared in our laboratories using 131I and 93mxc. These labelled hormones facilitated a lot of experiments to be carried out immediately when the patients are to be examined. Work on 35S thiourea was continued on cases of Pendred's Syndrome apd different types of hyperthyroidism. Blood curves were drawn to show the turnover of the substance in normal and abnormal metabolism of the thyroid gland. Iodotyrosines, iodothyronines and thyroxines have been prepared in good yield labelled with 13lI and 99mTc. The method of preparation depends on direct oxidation of the halogen and selecting a favourable pH value for the reaction. Separation of the labelled hormones from inorganic impurities was achieved by using a Sephadex column, or by the distillation technique. The use of isij- ancj 99mxc-tyrosines has helped in the investigation of enzymatic blocks, taking place in thyroid disorders. A test dose, of 1311- tyrosines or their 99m Xc analogues, was administered to normal and goitrous subjects. The urine was collected, separation of butanol extractable material from non-butanol extractable material was then undertaken. Radio- assay of 131I-tyrosine after butanol extraction and paper chromatography gave a quantitative measure of recovery of ingested tyrosines. Comparable data were analysed to determine the ratio of inorganic/organic compounds, interpretation being based on the results obtained in normal subjects. The radioisotope 99mXc is considered favourable for thyroid function tests due to its low gamma energy and short half-life. The use of 100 /uCi as a test dose for thyroid uptake gave promising results. In the same way elimination of pertechnetate in urine was found similar to that of inorganic 142 CAIRO iodine. Themechanism of coupling of pertechnetate with precursors of thyroid gland hormones was studied. Spectroscopy and paper chromatography proved that pertechnetate behaves exactly like iodide in entering the iodine cycle. Amino acids up to 99mTc-thyroxine were identified in the investigated cases. When 99mTc-tyrosine was ingested by normal or goitrous subjects, the behaviour of the substance was similar to that of iodotyrosine. The study of the incidence of goitre in two villages of the Egyptian oases Gedida and Qalamun was performed in 1966. The incidence of goitre was found to be high and fulfils the requirements of the term 'endemic'. Goitre was more prevalent in females than in males with a ratio of about 3:1. Nodular goitre was found to be more frequent in females than in males, and proved to be the predominant type in advanced age, irrespective of sex. The absence of hypothyroidism and the moderate size of the enlarged glands may be due to low protein diet. Our findings of low 131I urine excretion, together with low 1271 excretion, both in goitrous and non-goitrous individuals with insignificant difference, leads to the conclusion that the avidity of the gland in the oases is just the same in the thyroids of normal size as in obviously enlarged glands. Although different syndromes of genetic familial goitre are biochemically distinct, the clinical picture of all types is very similar. To-date, five distinct types of this abnormally metabolic goitre have been distinguished. These types are described to be due to deficiency of the iodine trapping mechanism, lack of peroxidase-iodinase system, lack of the iodotyrosine deiodinase, formation of abnormal iodoproteins and lack of the coupling enzyme system.

Medicine Team

(a) Bilharziasis Research Team

Prof. Dr. Mahmoud M. Badr, Dr. Mohamed Saif, and Dr. Mohammed A. Razzak.

(b) Goitre Research Team

Prof. Dr. Paul Ghalioungui, Dr. Mohammad F. Abdel-Wahab, Dr. Mohammed Salah Ibrahim, Dr. Mohammed R. Refaie, and Mr. Yakout M. Megahed. III. PUBLICATIONS, ACCEPTED PAPERS AND SCIENTIFIC REPORTS ON RESULTS OF WORK DONE IN THE CENTRE

Hydrology

HAZZAA, I.В., SAAD, K.F., GIRGIS, R.K., BAKR, A.A., SWAILEM, F.M., The investigation of the Wadi El-Natrun aquifer including determination of effective porosity, permeability, storage coefficient and transmissibility using different radioisotopes, J.Egypt. Soc. Eng. UAR 4 4 (1966) 63.

HAZZAA, I.В., GIRGIS, R.K., SAAD, K.F., SWAILEM, F.M., BAKR, A.A., Study of the applicability of different radioisotopes for determination of the porosity of ground-water aquifers, Int. J. appl. Radiat. Isotopes 17 (1966) 621.

HAZZAA, I.B., A modified method for the determination of aquifer parameters using radioactive isotopes, Int. J. appl. Radiat. Isotopes 17 (1966) 583.

HAZZAA, I.B., A radiographic method for investigation of the movement of sand and sediment in rivers using P-32, Int. J. appl. Radiat. Isotopes (1967, in press).

HASSAN, H.M., ABDEL-WAHAB, M.F., SOBHY, C.M., The dependence of photosynthesis on water and minerals supply. II. Effect of salinity on Vicia faba seedlings, Isotopenpraxis (in press).

Agriculture

ABDOU, Payez M., OSMAN, A.Z., Soil phosphorus evaluatign as estimated by L- and K-values, The UAR J. Soil Sci. (ih press).

ABDEL-SALAM, M.A., OSMAN, A.Z., Interaction of saline water irrigation and phosphorus fertilization on crop production, The UAR J. Soil Sci. 5 2, 2 (1965) 75-88.

Entomology

ABDEL-MALEK, A. A., ABDEL-AAL, M.A., Study of the dispersion and flight range of Anopheles sergenti ' Theo. at Siwa Oasis using radioisotopes as markers, World Health Organisation Document, WHO/Mal/66.568, WHO/VC/66.209. (1966).

TANTAWY, A.O., ABDEL-MALEK, A. A., WAKID, A.M., Studies on eradication of Anopheles pharoensis by the sterile-male technique using Co60. II. Induced dominant lethals in the immature stages, J. econ. Ent. 59 6 (1966) 1392-94.

Medicine

MOUSA, A.H., ATA, A.A., EL-ROOBY, A., EL-GAREM, A., SAIF, M., WAHHAB, F., ZEIN EL-ABEDINE, A., Further studies on the portal haemodynamics in hepatosplenic bilharziasis. B. Total blood volume and hepatic blood flow, Proc. 1st NtlSymp. on Bilharziasis, Cairo 1964.

143 144 CAIRO

MOUSA, A.H., EL-GAREM, A., SAIF, M., ZEIN EL-ABEDINE, A., The significance of estimating the hepatic blood flow in hepatosplenic bilharzial cases by the radiogold clearance and uptake methods. and its value in determining extent of porta-systemic collaterals, Pan-Arab Medical Congress, Khartoum, 1967.

SAIF, M., The validity of Schilling test in investigating the intestinal absorption of cyanocobalamin in Egyptians. A. The normal range, J. Egypt, med. Ass. (1967, in press).

SAIF, M., ABDALLAH, A., ABDEL-MEGUID, M., The validity of Schilling test in investigating the intestinal absorption of cyanocobalamin in Egyptians. B. The range in intestinal parasitic infections, J. Egypt, med. Ass. (1967, in press).

SAIF, M., ABDALLAH, A., ABDEL-MEGUID, M., ZEIN EL-ABEDINE. A., The validity of Schilling test in investigating the intestinal absorption of cyanocobalamin in Egyptians. C. The range in urinary and intestinal bilharziasis, J. Egypt, med. Ass. (1967, in press).

ABDEL-WAHAB, M.F., EL-GARHY, M.A., MEGAHED, Y.M., Preparation of technetium-99m, tyrosine, thyroxine, insulin and serum proteins labelled-Tc-99m, Radiochim. Acta 5 (1966) 111.

ABDEL-WAHAB, M.F., MEGAHED, Y.M., Incorporation of I131 and Tc-9sm in 3,5,5-triiodine, Radiochim. Acta 6 (1966) 52.

IBRAHIM, M.S., ABDEL-WAHAB, M.F., Free thyroxine concentration in human maternal and foetal blood, J. Med. Pharmacol. Exp. W (1966) 173.

IBRAHIM, M.S., ABDEL-WAHAB, M.F., MEGAHED, Y.M., Abnormal metabolism of thiourea-S-35 in Pendred's Syndrome, Endocrinologie (1966).

ABDEL-WAHAB, M.F., IBRAHIM, M.S., An appraisal of new radioisotope technique in the study of iodine metabolism, Isotopenpraxis (Í966).

ABDEL-WAHAB, M.F., HUSEIN, M.A., Thyroxine content in thyroid glands of domestic animals, Arzneimittel- Forschung (in press).

IBRAHIM, M.S., ABDEL-WAHAB, M.F., KHALIFA, S., MEGAHED, Y.M., Dyshormonogenetic goitres; A study of 46 cases, Radiológica diagnostica (in press).

ABDEL-WAHAB, M.F., IBRAHIM, M.S., MEGAHED, Y.M., Technetium-99m in the study of thyroid disorders, Life-Science (in press).

Scientific reports

HAZZAA, I.В., SAAD, K.F., GIRGIS, R.K., BAKR, A.A., SWAILEM. F.^., The investigation of the Wadi El-Natrun aquifer including determination of effective porosity, permeability, storage coefficient and transmissibility using different radioisotopes (Dec.1966); IAEA Research Contract No.302.

HAZZAA, I.В., SAAD, K.F., SHARHAN, A.M., AKHRAS.'n.C. , SHUHAIBER, Y.K., Investigation of underground water in Kuwait (May 1966).

ZEIN EL-ABEDINE, A., Research work within the framework of a coordinated programme on the application of radiation techniques to water use efficiency studies (Dec.l966)¡ IAEA Research Contract No. 310.. IV. LABORATORY, RESEARCH AND TRAINING FACILITIES

In 1966 the International Atomic Energy Agency placed an order for a gamma-cell to be delivered early in 1967. The Agency also provided the Centre with a second moisture measuring instrument (neutron source) under IAEA Research Contract No. 310. A device for tritium enrichment was built. These are additions to the equipment and facilities of the Centre described previously.2

2 The Radioisotope Centre, Atomic Energy Establishment, UAR (1962). INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, First Report, Technical Reports Series No.25, IAEA, Vienna (1964) 102. INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Second Report, Technical Reports-Series No.41, IAEA, Vienna (1965) 97. INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Laboratory Activities, Third Report, Technical Reports Series No.55, IAEA, Vienna (1966) 154.

145 V. SCIENTIFIC VISITS TO THE PARTICIPATING STATES AND THE IAEA

1. THE SUDAN

, A member of the scientific staff of the Centre visited the Sudan in November 1966 to study the conditions of extending the goitre research in the Sudan Republic. Due to his visit, the authorities in Khartoum agreed to co-operate with the staff of the Centre to carry out a study of goitre in Khartoum and Darfour and to study the different aspects of the problem according to the scheme previously followed by the Centre. Another member visited the Sudan in January 1967 for the same purpose.

2. IRAQ

A university professor, delegated to the Centre, visited the Iraq in April 1966 to discuss the possibilities of carrying out bilharziasis studies in the Iraq. The programme of work was concluded.

3. KUWAIT

The Centre provided some of the hydrology team with all the equipment and radioactive isotopes needed for carrying out the investigations of underground water in Kuwait. The field work in Kuwait started on 24 February 1966 and lasted until 8 March 1966. The first part of the work was the investigation of the Shigaya aquifer which by the State of Kuwait is considered an important new area. The team performed three sets of experiments, each comprising the porosity experiment and the pumping test using both the tape and the radioactive isotope methods in three areas: Rawdatain, Sulaibiyah and Shigaya. To get representing data for the groundwater aquifer in Kuwait, more experiments will be carried out in each area.

4. LIBYA

A research worker from the Centre visited Libya in August to collect groundwater samples from the Wadi Shatea, Wadi El Agol, El Goffra area. Gate Galo, Awgela oasis and Benghazy area including a few water sources from the Green Mountains. These samples are being analysed to determine their major constituents, and activation analyses were made to determine tbe trace elements.

146 CAIRO 147

5. THE AGENCY

(a) A demonstrator of the Centre was trained in the Agency's hydrology laboratories, in Vienna, in 'enrichment of tritium in water by electrolysis and its counting'. The training was undertaken during the period 11 May - 25 June 1966, under the supervision of the specialists of the Agency. The trainee made two visits to other laboratories in Vienna and to the hydrology experimental fields. (b) Another trainee was trained in 'the various methods of mass culturing of the Mediterranean fruit fly, Ceratitis capitata Wied'.

The training was undertaken at the entomology laboratory of the Agency at Seibersdorf from 18 May to 8 June 1966. VI. FINANCE-

The Agency's support to the Centre during 1966 amounted to US$30 900 under the Expanded Programme of Technical Assistance. The breakdown of 1966 expenditures and obligations under EPTA funds were as follows:

1966 Funds US$

Experts 4 683 Equipment 19 717 Fellowships 6 500

TOTAL 30 900

In addition to the Agency's contribution, the major operating costs of the Centre are met by a cash contribution of 35 000 Egyptian pounds (approximately $77 000) from the host country and annual pledges from the participating Arab countries. All facilities available at the Centre have been provided by the host government free of charge.

148

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