A BASIC TOXICITY CLASSIFICATION of RADIONUCLIDES the Following States Are Members of the International Atomic Energy Agency

TECHNICAL REPORTS SERIES No. 15

I \ Basic • Toxicity Classification

() f Radionuclides • REPORT OF JOINT STUDY OF A GROUP OF CONSULTANTS TO THE INTERNATIONAL ATOMIC ENERGY AGENCY

INTERNATIONAL ATOMIC ENERGY AGENCY - VIENNA 1963

A BASIC TOXICITY CLASSIFICATION OF RADIONUCLIDES The following States are Members of the International Atomic Energy Agency:

AFGHANISTAN ITALY ALBANIA JAPAN ARGENTINA REPUBLIC OF KOREA AUSTRALIA LEBANON AUSTRIA LIBERIA BELGIUM LUXEMBOURG BOLIVIA MALI BRAZIL MEXICO BULGARIA MONACO BURMA MOROCCO BYELORUSSIAN SOVIET SOCIALIST REPUBLIC NETHERLANDS CAMBODIA NEW ZEALAND CANADA NICARAGUA CEYLON NORWAY CHILE PAKISTAN CHINA PARAGUAY COLOMBIA PERU CONGO (LÊOPOLDVILLE). PHILIPPINES CUBA POLAND CZECHOSLOVAK SOCIALIST REPUBLIC PORTUGAL DENMARK ROMANIA DOMINICAN REPUBLIC SAUDI ARABIA ECUADOR SENEGAL EL SALVADOR SOUTH AFRICA ETHIOPIA SPAIN FINLAND SUDAN FRANCE SWEDEN FEDERAL REPUBLIC OF GERMANY SWITZERLAND GHANA THAILAND GREECE TUNISIA GUATEMALA TURKEY HAITI UKRAINIAN SOVIET SOCIALIST REPUBLIC HOLY SEE UNION OF SOVIET SOCIALIST REPUBLICS HONDURAS UNITED ARAB REPUBLIC HUNGARY UNITED KINGDOM OF GREAT BRITAIN AND ICELAND NORTHERN IRELAND INDIA UNITED STATES OF AMERICA INDONESIA URUGUAY IRAN VENEZUELA IRAQ VIET-NAM ISRAEL YUGOSLAVIA

The Agency's Statute was approved on 23 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, Kárntner Ring 11, Vienna I, Austria.

Printed by the IAEA in Austria April 1963 TECHNICAL REPORTS SERIES No. 15

A BASIC TOXICITY CLASSIFICATION OF RADIONUCLIDES

REPORT OF JOINT STUDY OF A GROUP OF CONSULTANTS TO THE INTERNATIONAL ATOMIC ENERGY AGENCY

INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA 1963 A BASIC TOXICITY CLASSIFICATION OF RADIONUCLIDES IAEA, VIENNA, 1963 STI/DOC/10/15 FOREWORD

To facilitate the application of radiation protection regulations and recommendations, it may be necessary in some cases to classify radionuclides into groups according to their radiotoxicity. The Agency convened a group of consultants to consider this problem and make a study of the radiotoxicity grading and grouping based on the data provided by the International Commission on Radio- logical Protection (ICRP), in particular the Report of Committee II on Permissible Dose for Internal Radiation. The result of such work is the present report which presents a basic toxicity classification of radionuclides. This classification, however, may need some adjustments when applied to operations which depart from the conditions upon which the classification was based.

CONTENTS

1. Introduction 9

2. Definition of Toxicity 10

3. Why is a Toxicity Grading and Classification Possible for Radionuclides! 11

4. Basis of the Toxicity Grading 11

5. Basic Toxicity Grading of Radionuclides 13

6. Basic Toxicity Classification taking into Account Specific Activity 14

Annexe I

Mathematical Basis of Toxicity Grading for Continuous or Single Intake of Radionuclides 16

1. INTRODUCTION

In the course of its work in the field of health and safety the International Atomic Energy Agency has often met the practical re- quirement for grading radionuclides in order of their relative radio- toxicities. This need was particularly evident when the Agency's Basic Safety Standards for the protection of health against ionizing radiation [3] were in preparation, when it was necessary to exempt quantities of radionuclides from inclusion in the norms. A basic toxicity grading might be of help to laboratories in meeting some of their requirements in problems related to waste management as well as for the design of experimental facilities. It should also serve as a basis for the development of safety criteria for laboratory equip- ment and procedures for handling and transporting various quantities and kinds of radionuclides. The purpose of the present Report is to make a toxicity grading of the radionuclides according to the risk of biological injury which they may cause when they have become incorporated in the human body. No account has been taken of the biological effects of radiation penetrating the body when the radionuclide is external to it. Inform- ation on the metabolism and subsequent biological risk from radionuclides taken into the body has been freely taken from the Report of Committee II of the International Commission on Radiological Pro- tection (ICRP) [1] . This information has been used in the present Report to show that a factor of about 108 in relative toxicity exists between radionuclides with the highest and lowest toxicities. Such a wide range of toxicities makes it necessary, especially in regu- latory procedures, to group the radionuclides within the toxicity grading so that recommendations or regulations may be made applicable to each of a small number of groups rather than to a large number of different toxicities of the individual radionuclides. In the present classification only three main groups have been distinguished. Radionuclides of high toxicity and those of low toxicity have been separated from a larger group of medium-toxicity nuclides. However, it is recognized that, for some purposes, the group of medium- toxicity nuclides may cover too wide a range of toxicity and therefore a further division is suggested which splits the group into two sub-groups. The exact arrangement of the toxicity grading and the division into groups may depend on the particular application for which it is required. The IAEA has already developed a toxicity classification of radionuclides for transport purposes [4]. While that classification may require some reconsideration with a view to modification in the

9 light of the present Report, it is recognized that the basic classification as derived here would not be directly applicable to transport without adjustment to take due account of factors and circumstances which are peculiar to such application. One special factor which is important in all applications of toxicity grading and classification is specific activity. Hence in this Re- port a method is given for taking specific activity into account in the classification.

2. DEFINITION OF TOXICITY

No agreed definition is available regarding what is meant by the toxicity of a radionuclide. However it may be useful to examine an accepted definition of chemical toxicity to see how it can guide the development of a similar definition for radionuclides. GOLDWATER [2] defines toxicity and the closely related concept of toxicity hazard as follows: "Toxicity is the ability of a chemical molecule or compound to produce injury once it reaches a susceptible site in or on the body. Toxicity hazard is the probability that injury may be caused by the manner in which the substance is used. " Similarly, we may adopt the following definition for the toxicity of a radionuclide: "The toxicity of a radionuclide is the ability of the nuclide to produce injury, by virtue of its emitted radiations, when incorporated in a body. " There are two important points of difference in the effects of a chemical toxin and a radionuclide which require some comment. Firstly, most attention is focused on the acute effects of chemical toxins, whereas the effects of all but the largest intake of radionuclides do not usually become apparent for several years, There- fore the degree of injury and the time of its manifestation are in general very different. Secondly, the susceptible site in the chemical definition has no exact counterpart in radionuclide definition but, in general, the site of greatest biological injury is in the body organ which accumulates the greatest concentration of the radionuclide. The body organ in which a radionuclide is most concentrated and the associated relative biological efficiency (RBE) dose is highest is, in general, called 'the critical organ' by the ICRP [1] . Factors other than the RBE dose were considered by the ICRP [1] in choosing the critical organ for a particular radionuclide, such as the essentiality of the organ and its radiosensitivity, but usually the RBE dose was the overriding consideration. A definition of toxicity hazard for a radionuclide may be obtained directly from that given by Goldwater for a chemical substance as follows:

10 "A toxicity hazard is the probability that injury may be caused by the manner in which the radionuclide is used. " If these proposed definitions of toxicity and toxicity hazard are accepted, then it becomes clear that the basic grading and classification of the radionuclides may be made purely on their toxicity, and any modification required due to the particular use of the radionuclide which might affect the probability of intake and subsequent injury as, for example, in the case of transport, changes the classification to one of toxicity hazard. Hence the present Report, in the terms of the above definitions, is concerned with a toxicity grading and classification and, in general, is not concerned with toxicity hazard.

3. WHY IS A TOXICITY GRADING AND CLASSIFICATION POSSIBLE FOR RADIONUCLIDES?

It is almost impossible to grade non-radioactive nuclides in order of their toxicity because there is no way of quantitatively comparing the various injuries produced or measuring the potentiality of a nuclide to produce injury when it is outside thé body. In the case of radionuclides the injury to the body comes from the radiations emitted, which are few in type and which have well-defined and measured physical properties. All types of radiation produce the same primary basic physicochemical effects of excitation and ioniza- tion within the biological material and they differ only in the spatial distribution and intensity of these effects. The types of irradiation emitted, and their energies, have been well-established for most radionuclides and the disintegration rate of any radioactive sample can be measured. Therefore if the concentration of a radionuclide by a body organ of known mass can be determined from experimental measurement, then the dose in rads delivered to the organ by the radionuclide can be calculated. If the ICRP [1] concepts are used, then this dose is multiplied by the RBE factor appropriate to the radiation delivering the dose in order to take into account the different amounts of biological damage caused by each type of ionizing radiation to the various body organs. In principle, the product RBE X dose (rad) is proportional to the risk of biological damage for all types of radiation.

4. BASIS OF ТЦЕ TOXICITY GRADING

The toxicity grading given below has been limited to those radionuclides listed by the ICRP [1] and no radioactive chemical compounds have been considered because of lack of a consistent set of data on the metabolic behaviour of compounds in the human body.,. For example, there are many compounds containing tritium, carbon,

11 sulphur, phosphorus and iodine which are readily available from isotope production centres which, if accidentally taken into the body, would be metabolized in a very different way from the elemental radionuclide. Hence this shortcoming in the toxicity grading should be kept in mind when using it. There are three important ways in which radionuclides normally enter the body — by absorption through the skin, by ingestion and by inhalation. Of these three modes of entry it was considered that inhalation was the most important because the other two are usually more readily controlled or avoided by taking simple precautions. Although in an accident or during the clean-up operations it is possible that radionuclides could enter the body through wound puncture, it is considered that this method of intake would be best taken into account in the particular circumstance rather than in the basic toxicity classification. This in fact was the case in the toxicity classification set up for purposes of safe transport [4J where it was considered that wound injection could occur during and after an accident. However, for the purposes of the basic toxicity grading and classification considered in the present Report, inhalation was taken to be the most significant mode of entry, and other modes were not taken into account. A further consideration in making the toxicity grading is the rate at which the radioactivity is inhaled. The grading may be based on the toxicity of the radionuclides due to their continuous intake, which is the most important consideration for workers directly en- gaged in radiation work. Alternatively,' the grading,may be based on an intake of short duration. This case is probably more important than continuous intake to the casual users, or those only likely to be in contact with radioactivity once in a life-time — for example, members of the public who inhale radioactive material after an accidental release to the environment. In Annex I to this Report the mathematical formulations for continuous and single intakes are set out in conformity with the concepts used by the ICRP [1] . This mathematical formulation shows that if equal daily intakes of radioactivity are limited such that after 50-yr continuous intake the dose-rate to the critical organ is, say, R rem per week, then for any given radionuclide this daily intake bears a constant relationship to the single intake which delivers a dose of R rem over the subsequent 50 yr to the same critical organ. In other words, within the ICRP concepts it is possible to have a toxicity grading which applies to continuous as well as short-term intakes. Therefore, although the classification is based on the ICRP [1] values for the maximum permissible concentrations in air (MPC)a* for continuous inhalation as described in the following section, it is also applicable to single inhalation.

* The sole exce ption being Rn222 where the figure used in this Report is an order of magnitude higher to conform with the IAEA Basic Safety Standards for Radiation ftotection [3] .

12 The only consistent set of data available for calculating the dose to body organs from known intakes of activity are given by the ICRP [1] . Therefore these ICRP data, including their concepts of a standard man and radiosensitivity of the body and organs, have been used in making the present toxicity grading. One major limitation involved in this approach is that the grading strictly applies to adults only and it is possible that some rearrangement might be necessary to take into account the differences in metabolic function and body-organ size between children and adults. However, no consistent set of appropriate data is available for a standard child and therefore it was not possible to take children into account.

5. BASIC TOXICITY GRADING OF RADIONUCLIDES

Continuous exposure at the appropriate maximum permissible concentrations (MPC) recommended by the ICRP [1] will eventually give rise to a dose-rate of 0.1, 0.3 or 0.6 rem per week in the critical organ. The three different dose-rates represent the differing radiosensitivities of the three classes of body organs. Hence the basic toxicity grading, based on the arrangement of the radionuclides

in order of their most restrictive value of (MPC)a for continuous inhalation, takes into account not only the RBE dose-rate but also the radiosensitivity of the critical organ.

The ICRP [1] give values of the (MPC)a for both soluble and insoluble forms of radionuclides and, for the purposes of the present Report, the more restrictive of these two values is used. The grading obtained in this way is given in Table I* where the 236 radionuclides considered are listed in order of their most restrictive value of (MPC)a. The radionuclides listed in Table I have been divided into three main toxicity groups, with a division of the large-medium group into two sub-groups to obtain a toxicity classification. In this kind of work the choice of the dividing lines is always somewhat arbitrary and justification for the actual position of the lines can only be made in general terms. Those in Table I were chosen in conjunction with another toxicity classification which takes into account the specific activity of the radionuclides as described in Section 6 of this Report. The boundary lines chosen are summarized in Table II. In Table II there is not exact equivalence between the values of (MPC)a and (MPI) given in columns 2 and 3 because the definition given in Section 6 shows that an (MPI) of 1 мс is equivalent to

1.37X 10"10цс/cm3. But values of (MPC)a are given by the ICRP [1] to the nearest whole number and the first significant value of (MPC)a less than 1.37X 10"10/uc/cm3 is 10 "10/лс/ст3 . Hence the lack of exact equivalence between the values of (MPC)a and (MPI) does not affect

* The Tables are to be found at the end of this Report.

13 the classification. In addition, some advantage lies in choosing round numbers for the boundary values of (MPI) due to the fact that no radionuclides actually fall on these values. The nuclides in the high-toxicity group include most of the bone- seeking, heavy transuranic nuclides and strontium-90 which is in accordance with common experience with those nuclides. The low- toxicity group contains radionuclides of short effective half-life in the body and low effective energy of disintegration which again is in accordance with common experience. The remainder of the nuclides form the medium-toxicity group. This is the largest group and for some purposes it might be thought desirable to divide the group into sub-groups. This has been done by taking a dividing line at an (MPI) of 100 /uc.

6. BASIC TOXICITY CLASSIFICATION TAKING INTO ACCOUNT SPECIFIC ACTIVITY

The specific activity of a radionuclide affects the probability that a given quantity of radioactivity may enter the body and affects its subsequent behaviour in the body. For example, radionuclides of very low specific activity, such as neodymium- 144, indium-115 and rubidium-87, have such a large mass associated with a unit of activity that it would be impossible for the body to take in a sufficient quantity of material for it to become radiologic ally toxic. In terms of the definition given in Section 2 of this Report it is the toxicity hazard which is under consideration when account is taken of the probability of intake and subsequent risk of biological damage. However, as the specific activity is an important inherent property of a radionuclide, it cannot be ignored in making a classification. Otherwise, as shown by the examples above, some low-specific-activity radionuclides may be assigned an absurdly high toxicity. It is therefore proposed to take specific activity into account but still to consider that the classification so produced is a basic toxicity classification and not a toxicity hazard classification in spite of the definition given in Section 2. In order to consider the effects of mass on the probability of entry of radioactivity into the body, it is necessary to choose the appropriate amount of radioactivity for each radionuclide so that the mass can be calculated. Guidance for the appropriate amount of activity was obtained from Paragraph 52 (g) of the ICRP Report [1] in which permissible limits of exposure during a period of emergency are given. The recommendations are that the dose to the critical organ during the 50 yr following, an intake shall not exceed the maximum yearly limit of (a) 12 rem for the whole body and the gonads; (b) 30 rem for the skin, thyroid and bone; and (c) 15 rem for all the other organs.

14 * The aiïiount of inhaled radioactive material which produces the doses mentioned above can be calculated from the values of (MPC)a as these doses will be delivered by the intake for one year. Hence the maximum permissible intake of radioactive material (MPI) /uc is given by

(MPI)MC = (MPC)aX2X 107X365 (1)

where (MPC)A is the most restrictive value for continuous inhalation given by the ICRP [1] and 2X 107X365 is the amount of air breathed by a standard man in one year. For those radionuclides where the whole body is the critical organ a value for (MPI)MC from Equation (1) has to be multiplied by the ratio 12/5 because the (MPC)a given by the ICRP [1] was calculated for a weekly dose-rate of only 0.1 rem, corresponding to an annual dose of only 5 rem, whereas the allowed annual dose in the above recommendation is 12 rem. The maximum permissible concentration for one year may be expressed as the product of the mass of the radionuclide and its specific activity; this value is denoted by (MPI)/ug. The values of (MPC)a, (MPI)/uc, and specific activity and (MPI)Mg are given in Table III. These data are also diagrammatically presented in Fig.l*, where a point for each nuclide has been plotted on a graph with axes (MPI)juc and (MPI)Mg. The basic toxicity classification given in Table I is also represented on this diagram by drawing three horizontal lines at the values of (MPI)/uc given in Table II. The effect of mass on the probability of intake was taken into account by considering the maximum amount of radioactive substance which is likely to be inhaled in a short time. It was thought unlikely that more than 10 mg of any radionuclide would be inhaled during the course of a single exposure. It should be noted that most radionuclides are associated with a stable isotope or other form of carrier substance and therefore are associated with a far greater mass than that considered here, which is the carrier-free mass. Therefore an atmosphere very heavily laden with dust would be required to contain, say, 10 mg of radionuclide per cubic metre, together with its carrier, which would, even then, have to be breathed for almost an hour before the intake reached 10 mg. Hence all the radionuclides which have a mass of greater than 10 mg associated with the (MPI)AÍC were placed in the lowest toxicity class. Another vertical line is shown in Fig. 1 at a value of (MPI)/ug of 100 ng. For reasons similar to those given above, it was thought that a radionuclide which had a mass of greater than lOO/ug associated with the (MPI)MC could not be placed in the highest toxicity group. Hence radionuclides which have a mass of between 100/ug and 10 mg associated with the (MPI)/LIC are placed in the medium

* Figure 1, "Table for a Basic Toxicity classification of Radionuclides" is attached to the back cover of this publication.

15 toxicity group, except those which have an (MPI)/лс greater than 104, in which case they are in the lowest toxicity group. Figure 1 shows graphically how the radionuclides are divided into three main groups —high, medium and low toxicity—by the two vertical and two horizontal full lines. For the purpose of general guidance only, the large medium-toxicity group has been subdivided into two subgroups by the horizontal dotted line drawn at an (MPI)/uc of 100/JC. No account is taken of the effect of specific activity in making this subdivision because it would be difficult to justify any finer distinc- tions in the choice of the amounts of mass intakes. The choice of IOOMC for the value of (MPI)MC at which to subdivide the medium toxicity group appears to be reasonable on the grounds that it occu- pies a convenient position between the other two dividing lines, and that radionuclides in common use, such as gold-198, iron-59, zinc-65 and strontium-85, are in the lower toxicity subgroup, whereas iodine-l3l, strontium-89, calcium-45 and cobalt-60, which are of recognized fairly high toxicity, fall into the higher toxicity subgroup. The result shown in Fig. 1 has been presented in Table IV, where the radionuclides are arranged according to their toxicity, and in alphabetical order, for easy reference.

ANNEX I

MATHEMATICAL BASIS OF TOXICITY GRADING. FOR CONTINUOUS OR SINGLE INTAKE OF RADIONUCLDES

The grading of radionuclides according to their toxicity may be based on the relative hazards due to continuous intake, which is probably the important consideration for radiation workers. In this case relative toxicities may be assigned from the values of the (MPC)a as given by the ICRP [1]. However, it may be important to consider a toxicity classification which is based on the hazard from a single intake. This is probably more important than continuous intake to the casual user of radionuclides or to those involved in accidental intakes of radioactive material. The mathematical concepts of these two types of toxicity classifications are set out below in order to show clearly the differences, if any, between them. The mathematical formulations given here are all in conformity with the ICRP concepts.

DOSIMETRY OF CONTINUOUS INHALATION

Let I be the permissible weekly inhalation (|ic) as set forth in the recommendations of the ICRP [1], X be the effective decay constant in the critical org.-'n,

and fabe the fraction of the inhaled activity retained in the critical organ.

In the time interval t to t+dt the amount of activity taken into the critical organ is fa Idt and the amount leaving the organ is X A dt, where A is the accumulation in the organ at time t. Hence the change in accumulation, dA, at time t is given by

dA = faIdt - X Adt.

16 The amount of activity accumulated in a working life of 50 yr (2600 weeks) is

2600

/ (faI- XA)dt = if (i-e-2600 \j 0 x

This amount of activity accumulated in the organ gives rise, after a continuous intake over 50 yr, to a dose-rate R, where R has the values 0.1, 0.3 or 0.6 rem per week depending on which organ is critical for the radionuclide under consideration. In the case of radionuclides with short effective half-lives in the critical organ, the accumulated activity reaches an equilibrium value in a few weeks but in the case of the long effective half-lives of some of the bone-seeking radionuclides equilibrium is not reached even after 50 yr. Let к be the dose in rem per week per lie of activity in the critical organ for the radionuclide considered, then R.the permissible weekly dose, is given in the expression

(i-e-2600 X)

and the permissible weekly inhalation is obtained by rearrangement as

XR 1 1

fak (l-e-2600 X) '

A toxicity grading could be made for all the radionuclides based on the relative values of I for each nuclide.

DOSIMETRY OF SINGLE INHALATION

The dose considered here is that which would be delivered to the critical organ in the 50-yr period subsequent to the intake. Let P be the amount of activity in microcuries which would result in a dose to the critical organ of 12, 15 or 30 rem in the subsequent 50 yr (2600 weeks). These are the doses to the appropriate critical organs as recommended in Para. 52 (g) of the ICRP Report [1] and used in Section 6 of this Report. The amount of a single inhalation remaining at time t after inhalation is

At faPe' ,

where the symbols fa and X have the same meaning as defined above. The weekly dose-rate is

kfaP e" and the total dose received by the critical organ in 50 yr is

2600 kf p ¿ kfaPe-Xt = ïiâil (1-е" 2600 X}.

The permissible doses to the critical organs are 12, 15 and 30 rem, which are roughly 50 times

17 the permissible weekly dose denoted by R in the case of continuous intake. Hence the value of P is obtained from the following equation

50R=^(l-e"2600 \y or

XR 1 50 kfa (i-e-zeoox.)-

On comparing the single intake P with the continuous permissible weekly intake I for a particular radionuclide and appropriate critical organs, we find that

P= 50 I.

Hence a toxicity grading based on P or I will be identical because the two parameters are related by a constant. There is, however, a small difference which has so far been overlooked and that concerns the case when the whole body is the critical organ. The permissible continuous exposure of the whole body is 0.1 rem per week when an equilibrium body burden has been reached. Hence the permissible annual intake of radioactive material produces only 5 rem in the following 50 yr, whereas a single intake which is not likely to be repeated is permissible to be 12 rem. Therefore the position of radionuclides for which the whole.body is the critical organ may change slightly in grading on I or P.

REFERENCES

[1] INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION, Report of Committee II on Permissible Dose for Internal Radiation, Pergamon Press (1959) 233 pp. [2] GOLDWATER, L.J. , Dangerous Properties of Industrial Materials, Reinhold Publ. Corp. (1957)1. [3] INTERNATIONAL ATOMIC ENERGY AGENCY, Basic Safety Standards for Radiation Protection, Safety Series 9. STI/PUB/26, IAEA, Vienna (1962) 60 pp. [4] INTERNATIONAL ATOMIC ENERGY AGENCY, Regulations for the Safe Transport of Radioactive Materials, Notes on Certain Aspects of the Regulations, Safety Series 7, STI/PUB/32, IAEA, Vienna (1961) 105 pp.

18 SYMBOLS OF THE ELEMENTS USED IN TABLES I-IV

actinium Ac helium He aluminium Al holmium Ho

americium Am hydrogen H

antimony Sb indium In

argon Ar iodine I

arsenic As iridium Ir

astatine At iron Fe

barium Ba krypton Кг

berkelium Bk lanthanum La

beryllium Be lead Pb

bismuth Bi lithium Li

boron В lutetium Lu

bromine Br magnesium Mg cadmium Cd manganese Mn

caesium Cs mendelevium Md

calcium Ca mercury Hg californium Cf molybdenum Mo carbon С neodymium Nd cerium Ce neon Ne chlorine Cl neptunium Np chromium Cr nickel Ni cobalt Co niobium Nb copper Cu nitrogen N curium Cm nobelium No dysprosium Dy osmium Os einsteinium Es oxygen 0 erbium Er palladium Pd europium Eu phosphorus P fermium Fm platinum Pt fluorine F plutonium Pu francium Fr polonium Po gadolinium Gd potassium К gallium Ga praseodymium Pr germanium Ge promethium Pm gold Au protactinium Pa hafnium Hf radium Ra SYMBOLS OF THE ELEMENTS USED IN TABLES I-IV (cont'd)

radon Rn rhenium Re

rhodium Rh rubidium Rb

ruthenium Ru samarium Sm .scandium Sc

selenium. Se silicon Si silver Ag sodium Na strontium Sr sulphur S tantalum Ta technetium Тс tellurium Те terbium Tb thallium TI. thorium Th thulium Tm tin Sn titanium Ti tungsten w uranium и vanadium V xenon Xe ytterbium Yb yttrium Y zinc Zn zirconium Zr TABLE III (continued)

RADIONUCLIDES ARRANGED IN ORDER OF THEIR MOST RESTRICTIVE (MPC)a VALUE

HIGH TOXICITY

P.231. cf249,Th-Nat,Pu239, Pu240, Pu242, Th232, Pu238, Ac227, Th230, Np237. Th228, Am241, Am243,

243 245 250 252 244 232 47 4 238 241 Cm , Cm , Cm2«, Cf , Cf , Cm , U , Ra 226 Ra228, Sml , U-Nat, Nd" , U , Pu ,

242 227 210 223 90 pb2M игзо^ цгзз^ £,234^ u235t и236 Cm , Th , Po , Ra Sr .

MEDIUM TOXICITY

Upper Sub-Group A

249 129 164 106 144 210 2 22 60 0 126 134 Ra224, Pa230, вк , I . Eu , Ru , Ce , Bi , At ", Na , Co , Ag" ™ I , 1131, Cs ,

2 Eu 152(13^ Cs137, Bi207 pb212 Ac228, In114m, sbl 4, Ta182_ cl36, Sc46, sb125, Ir192_ T1204_ Ca45,

Mil54, Y91, Zr95, Sr89. Cd1!5™, In115, Te127"1, Te129m, 1I33, Ba140, Tb160 , Tm170, Hf181, Th234 .

Lower Sub-Group В p32, y48, Fe59, Co58, Nl63, Zn65, Rb86, Rb87, Tc99, cd"9, Sn113, Pm147, Sm151, Os185, Hg203, As76, Y90, Zr97, Nb95, Ru103, Agios, Sn125, Csl35, Eu155, Gdl53, Bi2!2, K42, As74, Se75, sr85, Nb93m,

Zr93, je 125m, Te132, J135, La140, Tm171, w181, w185, Na24, Sc48, ^52, y93, Tc97m, sb122, Ce141,

142 Re183, й194, Bi206, Ca47_ Co57, Ga72_ •ft82iCd115i Te131m_ Cs136_ й143_ Ho166i £^188 _ р^ЗЗ,

Mo99, eel43, Dyl66, Tc96, Ag Щ 1I32, Ndl47, Pml49, Rel36, Au198, ^202, s35, Sr91, osl43, Zn69m, As73, As77, Sr92, Y92, Tc97, Pd109, Bal31, Sm153, Eu^f1-211), Gd159, Erl69, wl87, Osl91, Ir190,

Ptl93, Rn220, Rn222, * Se47, Mn56, Ni59, N¡65, ^87, Ru 105 Rh105, I134_ &l7i yb"5, Lu"7, Reí87,

55 27 97m 200 2 7 4 4 pt^l, и197, Au196, Np239, s¡31, Fe , Pdl°3, Tel , Au199, Hgl , TI , Tl °l, Be , A 1, Cu^ , Hgl97, Th231,Ndl49, Ru97, щ 115m, Pb203, ci38, Dyl65, Cr51, Fl», Cl4, Kr85m, Те"129, Xel35, Csl31.

LOW TOXICITY

3 69 71 97 3m 134m 193 58m 85 133 9 13 1 H , Zn , Ge. , Nb , InU , Cs , pt m, ptl97m, TcS9m _ Co , Kr , Xe , Osl !™, Xe !" , y91m, sr85m, Tc96m, [^ЮЗт, A37,

* The figure used for this isotope is the same as that given in Basic Safety Standards for Radiation tection [3].

22 TABLE III (continued)

(MPC)f AND (MPI)MC SPECIFIC ACTIVITY (c/g) AND (MPC)№

Radionuclides (MPC)£C * Maximum per- Specific Maximum per- arranged in (168 h/week value) missible intake activity missible in- order of in- in 1 yr expressed as • take in 1 yr creasing atomic (MPI)£C** c/g of the expressed in number expressed in цс radionuclide fig as a result as a result of in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC)Mg at (MPC)i¡c

H3 2 X 10"6 1.46 X 104 9.7 X 103 1.5

Be7 4 X 10"7 2.9 X 103 3.51 X 105 8.2 X 10"3

C14 10"6 7.3 X 103 4.59 1.58 X 103

18 7 5 F 9 X 10~7 6.57 X 103 9.3 X 10 7.06 X 10"

Na22 3 X 10"9 2.19 X 10 6.3 X 103 3.47 X 10"3

Na24 5 X 10"8 3. 65 X 102 8.7 X 106 4.2 X Ю"5

5 Si31 3 X 10"7 2.19 X 103 3.86 X 107 5.67 X 10~

p32 8 2 5 -4 2 X 10" 1.46 X 10 2.88 X 10 5.06 X 10

s35 8 2 4 -2 9 X 10" 6.57 X "10 4.29 X 10 1.531 X 10

CI36 8 X 10~9 5.84 X 10 0.0321 1.819 X 103

CI38 7 X 10"7 5.11 X 103 1.33 X 108 3.84X 10"5

Ar37 10"3 7.3 X 106 1.01 X 105 7.3 X 10

Ai41 4 X 1(T7 2.92 X 103 4.25 X 107 6.87 X W5

К42 4 X 10"8 2.92 X 102 6 X 10® 4.86 X Ю-5-

Ca45 10 "8 7.3 X 10 1.91 X 104 3.8 X 10"3

Ca47 6 X Ю-8 4.38 X 102 5.9 X 105 7.42 X 10"4

Se46 8 X 10"9 5.84 X 10 3.38 X 104 1.727 X 10"3

Se47 2 X 10"7 1.46 X 103 8.2 X 105 1.78 X 10"3

Se48 5 X 10"8 3.65 X 102 1.49 X 106 2.45 X 10-4

48 8 5 v 2 X 1(T 1.46 X 102 1.7 X 10 8.58 X 10"4

Cr51 8 X 10"7 5.84 X 103 9.2 X 104 6.34 X 10"2

Mn52 5 X 10"8 3.65 X 102 4.42 X 105 8.25 X 10"4

Mn54 10"8 7.3 X 10 8.3 X 103 8.79 X 10"3

* (MPC)£c These values are in conformity with the Agency's Basic Safety Standards for Radiation Protection [3] .

** (MPI)£C = (MPC)^c X 2 X 107 X 365. (MPC)^c = (MPI){^/specific activity (c/g) .

23 TABLE III (continued)

Radionuclides (MPC)jf* Maximum per- Specific Maximum per- arranged in (168 h/week value) missible intake activity missible in- order of in- in 1 yr expressed as take in 1 yr creasing atomic (MPI)£C** c/g of the expressed in number expressed in цс radionuclide |ig as a result as a result of in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC)^S at (MPC)^c

Mn56 2 X 10 "7 1.46 X 103 2.17 x 107 6.7 X 10"5

3 3 Fe55 3 X 10-v 2.19 X 10 2.22 X 10 0.9864

2 4 3 Fe59 2 X 10-8 1.46 X 10 4.92 X 10 2.96 X 10 "

Co57 6 X 10-8 4.38 x 102 8.5 X 103 5.15 X 10-2

Co58m 3 X 10-6 2.19 X 104 5.9 X 106 3.7 X 10-3

Co58 2 X 10-8 1.46 X 102 3.1 X lO4 4.7 X 10"S

C06O 3 X 10-9 2.19 X 10 1.14 X 103 1.92 X lO"2

N¡59 2 X 10-7 1.46 x 103 8.1 X 10-2 1.8 X 104

Ni63 2 X 10-8 1,46 X 102 7.15 X 10 2.04

Ni65 2 X 10"7 1.46 X 103 1.88 x 107 7.76 X 10-5

Cu64 4 X 10 "7 2.92 X 103 3.93 X 106 7.6 X 10"4

3 Zn65 2 X 10"8 1.46 X 102 8.2 X 10 1.78 X 10"2

69m 7 2 6 4 Zn 10 " 7. 3 X 10 3.29 X 10 2.21 X 10"

7 4 Zn69 2 X 10"6 1.46 x 104 5.3 X 10 2.7 X 10"

Ga72 6 X 10"8 4.38 X 102 3.09 x 106 1.42 X 10"4

2 Ge71 2 X 10"6 1.46 X 104 1.61 X 105 9.1 X 10"

2 As73 10 "7 7.3 X 10 2.36 X 104 3.09 X 10"2

2 5 3 As74 4 X 10"8 2.92 X 10 1.01 x 10 2.89 X 10"

As76 3 x 10"8 2.19 X 102 1.56 X 106 1.403 X 10"4

As77 10 "7 7.3 X 102 1.05 X 106 6.95 X 10"4

4 Se75 4 X 10"8 2.92 X 102 1.44 X 10 2.02 X 10"2

Br82 , : 6 x io"8 4.38 x 102 1.06 X 106 4.13 X 10 "4

85m 3 6 4 Kr 10 "6 7.3 X 10 ' 8.4 X 10 8.7 X 10" t o ю ¿ 2 3 X 10"6 2.19 X 104 3.97 X 102 5.51 X 10

7 Kr87 2 X 10 "7 1.46 X 103 2.77 X 10 5.27 X 10"5

4 3 Rb86 2 X 10 "8 1.46 X 102 8.1 x 10 1.8 x 10"

8 9 Rb87 2 X 10 "8 1.46 X 102 6.6 X 10" 2.2 X 10

85m 4 7 3 Sr ,10"5 7.3 X 10 3.16 X 10 2.31 X 10 "

2 Sr85 4 X 10 "8 2.92 X 102 2.37 X 104 1.23 X 10"

24 TABLE III (continued)

Radionuclides (MPC)£° * Maximum per- Specific Maximum per- arranged in (168 h/week value) missible intake activity missible in- order of in- in 1 yr expressed as take in 1 yr creasing atomic (MPI)£C** c/gofthe expressed in number expressed in дс radionuclide as a result as a result of in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC) at (MPC)£c

Sr89 10 "8 7.3 X 10 2.88 X 104 2.53 X 10 "3

Sr90 10-10 0.73 1.45 X 102 5 X 10 "3

Sr91 9 X 10"8 6.57 x 102 3.56 X 106 1.845 X 10"4

Sr92 10 "7 7.3 X It? 1.26 X 107 5.79 X 10"5 90 y 3 X 10"8 2.19 x 102 5.3 X 105 4.1 X 10"4 91m Y 6 x 10"6 4.38 x 104 4.11 X 107 .1.09 X 10"3 91 y 10 "8 7.3 X 10 2.5 X 104 2.92 X 1Q"3 92 y 10-7 7.3 X 102 9.5 X 106 7.6 X 10"5 93 y 5 X 10"8 3.65 X 102 3.24 X 106 1.12 x 10"4

Zr93 4 X 10"8 2.92 X 102 3.5 X 10"3 8.3 X 104

Zr95 10 "8 7.3 X 10 2.12 X 104 3.4 X 10"3

Zr97 3 X 10"8 2.19 X 102 1.9 X 106 1.15 X 10"4

93m 8 2 Nb 4 X 10" 2.92 X 102 3.79 X 10 7.7 X 10"1

Nb95 3 X 10"8 2.19 x 102 3.93 X 104 5.57 X 10"3

Nb97 2 X 10"6 1.46 X 104 2.61 X 107 5.59 X 10"4 '

Mo90 7 X 10"8 5.11 x 102 4.73 X 105 1.08 X 10"3

96m 4 Tc 10~5 7.3 X 10 3.81 X 107 1.9 X 10"3

96, 8 Tc 8 X 10" 5. 84 X 102 3.24 X 105 1.8 X 10"3 97m Tc 5 X 10"8 3.65 X 102 1.84 X 104 1.98 X 10"2

Tc97 10 "7 7.3 X 102 3.7 X 10"1 2 X 103

99m 6 Tc 5 X 10"6 3.65 X 104 5.2 X 10 7.02 X 10"3

Tc99 2 X 10"8 1.46 X 102 1.71 X 10"2 8.53 X 103

Ru97 6 X 10 "7 4.38 X 103 5.5 X 105 7.9 X 10"3

Ru103 3 X 10"8 2.19 X 102 3.19 x 104 6.86 X 10"3

Ru105 2 X 10"7 1.46 X 103 6.6 X 106 2.2.x 10"4

Ru106 2 X 10"9 1.46 X 10 3.38 X 103 4.3 X 10"3

103ш 3 № 2 X 10"5 1.46 X 105 . 3.21 X 107 4.54 X 10 "

Rh105 2 X 10 ~7 1.46 X 103 8.2 X 105 1.78 X 10"3

103 4 2 Pd 3 X 10"7 2.19 X 103 7. 5 X 10 2.92 X 10 "

109 2 4 Pd 10 "7 7.3 X 10 2.12 X 106 3.44 X 10 "

25 TABLE III (continued)

Radionuclides (MPC)f * Maximum per- Specific Maximum per- arranged in (168 h/week value) missible intake activity missible in- order of in- in 1 yr expressed as take in 1 yr creasing atomic (MPI)gc** c/g of the expressed in number expressed in дс radionuclide pg as a result as a result of in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC)№ at (MPC)

Ag105 3 X 10"8 2.19 X 102 3.11 x 104 7 X 10"3 U0m Ag 3 X 10"9 2.19 X 101 4.7 X 103 4.65 X 10"3 11 V 8 X 10"8 5.84 X 102 1.57 x 105 3.71 X 10"3 Cd109 2 X 10"8 1.46 X 102 2.55 X 103 5.72 X 10"2 115m cd 10 "8 7. 3 X 10 2.64 X 104 2.77 x 10"3

115 5 Cd 6 X 10"8 4.38 X 102 5.1 X 10 8.58 X 10"4

113m 7 In 2 X 10"6 1.46 X 104 1.6 X 10 '9.1 X 10"4

114m In 7 X 10"9 5.11 X 10 2.29 X 104 2.23 X 10"3

115m In 6 X 10"7 4.38 X 103 6.1 x 106 7.18 X 10"4

in115 10 "8 7.3 X 10 5.2 X 10"12 1.4 X 1013

Sn113 2 X 10"8 1.46 X 102 9.7 X 103 1.5 X 10"2

Sn125 3 X 10"8 2.19 X 102 1.1 X 105 1.99 X 10"3

Sb122 5 X 10"8 3. 65 X 102 3.9 x 105 9.35 X 10'4

Sb124 7 X 10"9 5.11 X 10 1.76 X 104 2.9 X 10"3

Sb125 9 X 10"9 6.57 X 10 1.43 X 103 4.59 X 10"2

125m 4 2 Te 4 X 10"8 2.92 X 102 1.8 x 10 1.62 X 10" 127m Te 10 "8 7.3 X 10 9.8 X 103 7.4 X 10"3

Te127 . 3 X 10"7 2.19 X 103 2.63 X 106 8.3 X 10"4 129m Te 10 "8 7.3 X 10 2.47 x 104 2.96 X 10"3

Te129 10 "6 7.3 X 103 1.97 x 107 3.7 X 10"4 131m Te 6 X 10"8 4.38 X 102 8 X 105 5.47 X 10"4

Те132 4 X 10"8 2.92 X 102 3.06 X 105 9.54 X 10"4

¡126 4 3 X 10"9 2.19 X 10 7.8 X 104 2.8 X 10"

¡129 4 6 X 10 ~10 4.38 1.62 X 10"4 2.7 X 10 jl31 3 X 10"9 2.19 X 10 1.23 X 105 1.78 X 10"4 ¡132 8 X 10 "8 5.84 X 102 1.07 X 107 5.45 X 10 "5 jl33 10 "8 7.3 X 10 1.13 X 106 6.46 X 10"5

jl34 2 X 10"7 1.46 X 103 2.68 X 107 5.44 X 10"5 ¡135 4 X 10 "8 2.92 X 102 3.48 X 106 8.39 X 10"5

26 TABLE III (continued)

Radionuclides (MPC)^c * Maximum per- Specific Maximum per- arranged in (168 h/week value) missible intake acitivity missible in- order of in- in 1 yr expressed as take in 1 yr creasing atomic (MPI) * c/g of the expressed in number expressed in цс radionuclide |jg as a result as a result of in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC)Mg at (MPC)

131m 6 4 1 Xe 4 X'10" 2.92 X 104 8.3 X 10 3.5 X 10"

Xe133 3 X 10"6 2.19 X 104 1.86 X 105 1.17 x 10"1

Xe135 10"6 7.3 X 103 2.54 X 106 2.87 X 10"3

2 Cs131 10 "6 7.3 X 103 1.105 7.3 X 10"

134m 6 6 Cs 2 X 10" 1.46 X 104 . 7.4 X 10 1.9 X 10"3

Cs134 4 X 10"9 2.92 X 10 1. 22 X 103 2.39 X 10"2

Cs135 3 X 10 "8 2.19 X 102 8.8 X 10"4 2.48 x 105

4 Cs136 6 X 10"8 4.38 x 102 7.4 x 10 5.9 X 10"3

Cs137 5 X 10 "9 3.65 X 10 9.82 X 10 3.71 X 10"1

Ba131 10 "7 7.3 X 102 8.7 X 104 8.39 X 10"3

Ba14° 10 "8 7. 3 X 10 7.3 X 104 10 "3

La140 4 X 10"8 2.92 X 102 5.6 X 105 5.21 X 10"4

2 Ce141 5 X 10"8 3.65 X 102 2.8 x 104 1.3 X 10"

5 4 Ce143 7 X 10 "8 5.11 X 102 6.6 X 10 7.7 X 10"

3 Ce144 2 X 10"9 1.46 X 10 3.18 X 103 4.5 X 10"

142 6 4 Pr 5 X 10"8 3.65 X 102 1.15 X 10 3.17 X 10"

143 8 2 4 3 Pr 6 X 10 " 4.38 X 10 6.6 x 10 6.64 X 10"

Nd144 3 X 10 "n 2.19 X 10 1.24 X 10"12 1.76 X 1011

3 Nd147 8 X 10 "8 5.84 X 102 8 X 104 7.3 X 10"

4 Nd149 5 X 10"7 3.65 X 103 1.07 X 107 3.5 X 10"

2 1 Pm147 2 X 10"8 1.46 X 102 9.6 X 10 1.52 X 10"

2 Pm149 8 X 10 "8 5.84 X 10 4.21 X 105 1.38 X 10"3

Sm147 2 X 10"11 1.46 X 10"1 1.95 X 10"8 7.48 x 106

Sm151 2 X 10~8 1.46 X 102 2.55 X 10 5.7

Sm153 10 "7 7.3 X 102 4.35 X 105 1.67 X 10"3

6 Eu152 (9. 2 h) 10 "7 7.3 X 102 2.24 X 10 3.25 X 10"4

Eu152 (13 yr) 4 X 10"9 2.92 X 10 1.85 X 102 1.57 X 10"1

Eu154 10 "9 7.3 1.45 X 102 5.03 X 10"2

Eu155 3 X 10"8 2.19 X 102 1.36 X 103 1.61 X 10

27 TABLE III (continued)

Radionuclides (MPC)^c * Maximum per- Specific Maximum per- arranged in (168h/week value) missible intake activity missible in- order of in- in 1 yr expressed as take in 1 yr creasing atomic (MPI)^C * * c/g of the expressed in number expressed in ¡Ас radionuclide jig as a result as a result of in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC) at (MPC)^c

Gd153 3 X 10"8 2.19 X 102 3.62 x 103 6.04 X 10~2

Gd159 lo"7 7.3 X 102 1.1 X 106 6.63 X 10"4

160 Tb 10 "8 7.3 X 10 1.11 X 104 6.58 X 10"3

Dy165 7 X 10 "7 5.11 X 103 8.2 X 106 6.2 X 10"4

5 Dy166 7 X 10 "8 5.11 X 102 2.3 X 10 2.22 X 10"3

Ho166 6 X 10 "8 4.38 X 102 6.9 X 105 6.4 X 10"4

Er1S9 10 "7 7.3 X 102 8.2 X 104 8.9 X 10"3

4 Et171 2 X 10 "7 1.46 x 103 • 2.35 X 106 6.2 X 10"

Tm170 10 "8 7.3 X 10 6 X 103 1.21 X 10"2

1 ТШ111 4 X 10"8 2.92 x 102 1.12 X 103 2.6 X 10"-

Yb175 2 X 10 "7 1.46 X 103 1.78 X 105 8.2 X 10"3

Lu177 2 X 10"7 1.46 X 103 1.09 x 105 1.31 X 10"2

181 4 3 Hf 10 "8 7.3 X 10 1.62 X 10 4.50 X 10"

3 3 Ta182 7 X 10 "9 5.1 X 10 6.2 X 10 8.2 X 10"

2 W181 4 X 10"8 2.92 X 102 4.98 x 103 5.86 X 10"

3 2 W185 4 X 10"8 2.92 x 102 9.7 X 10 3 X 10 "

2 3 W187 10 "7 7.3 X 10 7 x 105 1.04 X 10"

3 2 Re183 5 X 10"8 3.65 X 102 9.7 X 10 3.67 X 10"

Re186 8 X 10"8 5.84 X 102 1.9 x 105 3.07 X 10"3

Re187 2 X 10 "7 1.46 x 103 3.83 X 10"8 3.81 x 1010

Re188 6 X 10"8 4.38 X 102 1 X 106 4. 38 x 10"4

8 2 3 2 OS185 2 X 10" 1.46 X 10 7.3 X 10 2 X 10"

191m 2 0s 3 X 10"6 2.19 X 104 1.17 X 10® 1.87 X 10"

Os191 10 "7 7.3 X 102 4. 56 X 104 1.60 X 10"2

5 Os193 9 X 10"8 6.57 x 102 5.3 X 10 1.239 X 10"3

Ir190 10'7 7.3 X 102 6.2 X 104 1.177 X 10"2

192 3 Ir 9 X 10 "9 6.57 X 10 9.1 x 103 7.22 X 10"

194 5 4 lr 5 X 10"8 3.65 X 102 8.5 X 10 4.29 X 10"

Pt191 2 X 10"7 1.46 X 103 2.28 x 105 6.4 X 10"3

28 TABLE III (continued)

Radionuclides (MPC)£c * Maximum per- Specific •Maximum per- arranged in (168 h/week value) missible intake activity missible in- order of in- in 1 yr expressed as take in 1 yr creasing atomic (MPI)f ** c/g of the expressed in number expressed in ¡te radionuclide iig as a result as a result of in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC) at (MPC)£c

193m 6 4 2 pt 2 X 10" 1.46 X 10 1.99 x 105 7.33 x 10~

193 2 2 pt lO"7 7.3 X 10 3.76 1.094 X 10

197m 7 3 pt 2 X 10"6 1.46 X 104 1.22 X 10 1.196 X 10~

197 7 3 5 3 Pt 2 X 10" 1.46 X 10 8.8 x 10 1.65 x 10"

5 Au196 2 X 10"7 1.46 X 103 1.2 X 10 1.22 x 10"2

Au198 8 x 10"8 5.84 X 102 2.45 x 105 2.38 X 10"3

Au199 3 X 10"7 2.19 X 103 2.09 X 105 1.04 X 10"2

197m 5 3 Hg 3 X 10"7 2.19 X 103 6.6 X 10 3.32 X 10"

3 5 2 Hg197 4 X 10"7 2.92 X 10 2.45 X 10 1.19 X 10 "

Hg203 2 X 10"8 1.46 X 102 1.37 x 104 1.0 X 10"2

200 3 5 3 TJ 4 X 10"7 2.92 X 10 5.8 x 10 5.03 X 10"

201 5 2 T1 3 X 10"7 2.19 X 103 2.17 X 10 1 X 10"

202 2 4 2 T1 8 x 1Q"8 5.84 X 10 5.4 X 10 1.08 X 10"

204 1 T1 9 X 10"9 6.57 X 10 4.28 X 102 1.50 X 10"

203 2 pb 6 x 10"7 4.38 X 103 2.97 X 105 1.47 X 10"

210 1 3 Pb 4 X 10"11 2.92 X 10" 88 3 X 10 "

p 212 6 5 b 6 X 10 ~9 4.38 X 10 1.4 X 10 3.13 X 10"

4 Bi206 . ' 5 X 10"8 3.6 X 102 9.9 x 10 3.68 X 10"3

Bi207 ' 5 X 10"9 3.65 X 10 2.16 X 102 1.68 X 10"1

210 9 5 4 Bi 2 X 10" 1.46 X 10 1.24 X 10 1.17 X 10"

Bi212 3 X 10"8 • 2.19 X 102 1.47 X 107 1.489 X 10"5

3 4 Po210 7 X 10"11 5.11 X 10"1 4. 5 X 10 1.14 X 10"

6 At211 2 X 10 "9 1.46 X 10 2.06 x 106 7.1 X 10~

7 Rn220 10 "7 7.3 X 102 9.4 x 108 7.8 X 10~

3 Rn222 10 "7 7.3 X 102 1.54 X 105 4.9 X 10"

Ra223 8 X 10"11 5.84 X 10"1 .5 X 104 1.2 X 10~5

5 6 Ra224 2 X 10 "10 1.46 1. 6 X 10 9.1 X 10"

2 Ra226 lO"11 7.3 X 10"2 0.98 7.5 X 10~

2 4 Ra228 10-11 7.3 X 10 " 2.34 X 102 3.1 X 10"

5 Ac227 8 X 10"13 5.84 X 10"3 72 8 X 10"

29 TABLE III (continued)

Radionuclides (MPC)Mc * Maximum per- Specific Maximum per- arranged in (168 h/week value) missible intake activity missible in- order of in- in 1 yr expressed as take in 1 yr creasing atomic (MPI)f ** c/g of the expressed in number expressed in цс radionuclide ^ig as a result as a result of in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC) j^® at (MPC)^c

Ac228 6 X 10"9 4.38 X 10 2.24 X 106 1.95 X 10"5

227 Th 6 X 10"11 4.38 X 10 3.17 X 104 1.38 X 10 "5

2 Th228 2 X 10"12 1.46 X 10"2 8.3 X 10 1.75 X 10 "5 230 Th 8 X 10"13 5.84 X 10"3 1.94 X 10"2 3.01 X 10"1

Th231 4 X 10"7 2.92 X 103 5.3 X 105 5.5 X 10"3

232 2 Th lo"11 . 7.3 X 10~ 1.11 X 10"7 6.64 X 105

Th234 10 "8 7.3 X 10 2.32 X 104 3.10 X 10"3

2 Th-Nat 10-11 7.3 X 10" 1.1 X 10 "7 6.64 X 105

Pa230 3 X 10"10 2.19 3.21 X 104 6.8 X 10 "5

Pa231 4 X 10"13 2.92 X 10"3 4.52 X 10"2 6.47 x 10"2

Pa233 , 6 X 10"8 4.38 x 102 2.08 x 104 2.10 X 10"2 230 ц 4 X 10"11 2.92 X 10"1 2.73 X 104 1.06 X 10~5 232 ц 9 x 10"12 6.57 X 10"2 20.8 3.15 X 10"3 233 ц 4 X 10"11 2.92 X 10 9.5 X 10"3 3.07 X 10

и234 4 X 10"11 2.92 X 10"1 6.2 X 10"3 4.70 X 10 235 и 4 X 10"11 2.92 X 10"1 2.14 X 10"6 1.36 X 105

236 5 3 ц 4 X 10 "П 2.92 X 10 6.3 X 10" 4.7 x 10

238 ц 3 X 10"11 2.19 X 10-1 3.33 X 10"7 6.57 X 105

U-Nat 2 X 10"11 1.46 X 10"1 3.3 X 10"7 4.4 X 105

Np237 lO"12 7.3 X 10"3 6.9 X 10"4 1.05 X 10

239 7 3 5 3 NP 2 X 10" 1.46 X 10 2.33 X 10 6.26 X 10"

Pu238 7 x 10"13 5.11 X 10"3 16.8 3 X 10-4

Pu239 6 X 10"13 4.38 X 10 "3 6.1 X 10"2 7.18 X 10"2

Pu240 6 x 10"13 4.38 X 10 "3 0.227 1.929 X 10"2

Pu241 3 x 10"11 2.19 X 10"1 1.14 X 102 1.92 X 10"3

Pu242 6 x 10"13 4.38 X 10"3 3.9 X 10"3 1.12

Am241 2 x 10"12 1.46 X 10 "2 3.24 4.5 X 10 "3

Am243 2 x lo"12 1.46 X 10 "2 0.185 7.89 X 10"2

Cm242 4 x 10"11 2.92 X 10 3.32 X 103 8.79 X 10"5

30 TABLE III (continued)

Radionuclides (MPC) * Maximum per- Specific Maximum per- arranged in (168h/week value) missible intake activity missible in- order of in- in 1 yr expressed as take in 1 yr creasing atomic (MPI)jJc ** c/g of the expressed in number expressed in цс radionuclide fig as a result as a result of - in the carrier- of continuous continuous uni- free state uniform ex- form exposure posure at (MPC)№ at(MPC)Mc

4 Cm243 2X10"12 1.46 X 10 "2 42.1 3.4 X 10"

Cm244 3 X 10"12 2.19 X 10"2 82 2.6 X 10"4

1 Cm245 2 X 10~12 1.46 X 10 "2 1.04 X 10"1 1.4 X 10"

1 Cm246 2 X 10 "12 1.46 X 10 "2 3.64 X 10" 4.01 X 10"2

3 Bk249 3 X 10"10 2.19 1.80 x 103 1.216 X 10"

Cf249 5 X 10"13 3,65 X 10 "3 3.05 1.19 X 10"3

250 2 4 cf 2 X 10"12 1.46 X 10 "2 1.31 X 10 1.11 X 10"

2 Cf252 2 X 10"12 1.46 X 10 "2 6.5 X 10 2.24 X 10"6

31 TABLE III (continued)

RADIONUCLIDES CLASSIFIED ACCORDING TO THEIR RADIOTOXICITY

Radionuclides Number* indi- Radionuclides arranged Number* indi- (in alphabetical cating rank of according to their cating rank of order) radionuclides relative radiotoxicity radionuclides in the Table in the Table

Ac227 7 Pa231 1

Ac228 50 Cf249 2

240 Ag105 95 Pu 3 Ag110m 44 Pu239 > * * 4

Ag1U 140 PU242 5 Am241 14 Pu238 6

Am243 16 Ac227 7 • ** Ar37 236 Th230 8

Ar41 185 NP237 9

As73 161 H Th228 . ' 10

As74 102 - Cf252 11 U As76 90 - Cf250 12

As77 154 * Cm243 13

At211 37 H Am241 • * * 14

Au196 176 Œ

Au198 138 ° Cm246 15

Au199 182 X Am243 16

Ba131 157 Cm245 . 17

Ва140 61 Cm244 18

ц232 Be7 189 19

206 228 Bi 117 Ra * * 20 Bi207 48 Ra226 , 21

Bi210 38 Pu241 22

Ц23Ь Bi212 88 23

Bk249 35 Cm242 * * 24

Br82 122 Pb210 25

* This number only serves as an Indication of where to find the radionuclide (rank) and has no numerical significance beyond that.

* * This bracket indicates that these radionuclides have the same value for MPI expressed in fic and they are arranged according to the MPI expressed in )jg in increasing order.

32 TABLE III (continued)

Radionuclides Number * indi- Radionuclides arranged Number * indi- (in alphabetical cating rank of according to their cating rank of order). radionuclides relative radiotoxicity radionuclides in the Table in the Table

c14 203 u233 26

Ca45 68 G "234 Г* 27 Ca47 126 £ Th227 28 О H po210 Cd109 83 29

cd115m 63 1 Ra223 30

ï Sr90 Cd115 127 31

Ce141 118 U236 32

Ce143 132 Ra224 33

Ce144 40 Pa230 34 1 cf249 249 2 Bk Г* 35 cf250 12 Eu154 36

cf252 11 At211 37

Bi210 CI36 56 38 > * îjc CI38 195 * Ru106 39

Cm242 24 b Ce144 40 " ,131 243 41 Cm 13 и 1 „ j 126 Cm244 18 42 * 92 245 > • * Cm 17 О Na 43 Upper A (_ Agll0m Cm246 15 44

Co57 131 2 Co60 . 45

134 Co58™ 226 ! Cs 1 • 46 58 D EU152>- CO 78 Г* 47 Co60 45 ^ Bi207 : i 48 • * * Cr51 197 Cs137 . 49

Cs131 202 Ac228 50 • ** Cs134m 222 .Pb212 51

: In114m Cs134 46 52

Cs135 214 Sb124 > * * 53

Cs136 128 Та182 . 54 Cs137 49 ' Se46 . ' > ** 55 Cu64 186 Cl36 J 56

33 TABLE III (continued)

Radionuclides Number * indi- Radionuclides arranged Number * indi- (in alphabetical cating rank of according to their cating rank of order) radionuclides relative radiotoxicity radionuclides in the Table in the Table

192 Dy165 196 S !H" IIrr 57 Dy166 134 S У oul25 S * sb 58 2 g T,204 Er169 158 59

,133 Er171 169 60

Eu152(h) 151 Ba140 61

Eu152W 47 Sr89 62

Eu154 36 * Cd115m 63

Eu155 97 „ y91 64 '

F18 198 " Te129m 65 234 Fe55 184 X xh 66 О 95 • * * Fe59 77 Upper A H Zr 67

72 4 Ga 121 2 Ca * 68

Gd153 96 a Hf181 69

159 Gd 153 D Ge" 224 ы Tb160 70

H3 225 2 Te127m 71

Hf181 69 Mn54 72

Hg197m 180 Tm170 . 73

Hg197 190 p32 74 Hg203 79 V48 75

Но166 125 Rb86 76

,126 42 H Fe59 77

j 129 211 " Co58 78 и j 131 41 - Hg203 79

,132 135 o sn"3 80 > ** Lower В H Zn65 ,133 60 81

,134 165 S Os185 82

,135 99 = Cd109. 83

,n113m 220 O Pm147 84

,n114m 52 " Ni63 85 2 ,n115m 192 Sm151 86

In115 212 Te99 87

34 TABLE III (continued)

Radionuclides Number * indi- Radionuclides arranged Number * indi- (in alphabetical cating rank of according to their cating rank of order) radionuclides relative radiotoxicity radionuclides in the Table in the Table

212 Ir190 159 Bl 88 Ir192 57 Zr97 89

Ir194 114 As76 90

y90 K42 98 91 Kr85m 200 Sn125 92

Kr85 229 Nb95 93

Kr87 164 Ru103 94

La140 100 Ag105 95 Lu177 177 Gd153 96

Mn52 115 Eu155 • 97

Mn54 72 К42 . 98 j 135 Mn56 166 99

Mo" 138 !" La140 100

Na22 43 * Те132 101 и Na24 110

№93Ш 109 К As74 102

О SrS5 Nb95 93 > * & 103 H Lower В Xe125m Nb97 219 104 . s Nd144 209 B Se 105

« w185 Nd147 141 106 Q Nd149 191 « w181 107

Ni59 216 S Tm171 108

Ni63 85 Nb93m 109

№65 167 Na24 ' 110

Y93 Np237 9 111

Np239 173 . Sc48 112

Pr142 OS185 82 113

Ir194 0s191m 227 114

Os191 160 Mn52 ' * * 115

Os193 144 Sb122 116

Bi206 p32 74 117

Pa230 34 Ce141 • 118

Tc97m Pa231 1 119

Pa233 130 Re183 120

35 TABLE III (continued)

Radionuclides Number * indi- Radionuclides arranged Number * indi- (in alphabetical cating rank of according to their cating rank of order) radionuclides relative radiotoxicity radionuclides in the Table in the Table

pb203 194 Ga72 121

pb210 25 Br82 122

Pb212 51 Re188 123

Te131m Pd103 183 124

pd109 152 Ho166 125

Pm147 . 84 Ca47 126

Pm149 136 Cd115 127

Po210 29 Cs136 . 128

pr143 Pr142 113 129

Pr143 129 Pa233 130

pt191 174 Co57 . 131

Pt 193m 223 Ce143 132 >- Pt193 162 ' H Mo99 - 133

Pt197m 221 ~ Dy166 134 и ' pt197 170 « ¡132 135

Pu238 6 136 О p-149 Pu239 4 Lower В H Тс96 137

Pu240 3 S Au198 138 > * * , Pu241 22 ® Re186 139

Pu242 5 O Ag111 140

7 Ra223 30 » Nd" 141

T1202 Ra224 33 142

Ra226 21 Sr91 143

• ** Ra228 20 Os193 144

Rb86 76 S35 145

Rb87 213 Rn220 ' 146

Re183 120 Rn222 147

Re186 139 Sr92 148

y92 Re187 217 149 • * * Zn69m Re188 123 150

Rh103m 235 Eu152h 151

Pd109 Rh105 172 152

Rn220 146 Gd159 153

36 TABLE III (continued)

Radionuclides Number * indi- Radionuclides arranged Number * indi- (in alphabetical cating rank of according to their cating rank of order) radionuclides relative radiotoxicity radionuclides in the Table in the Table

Rn222 147 As77 154

Ru97 193 W187 155

Ru103 . 94 Sm153 156

Ru105 168 Ba131 157

Ru106 39 Er169 158 > ** Ir190 s35 145 159

Sb122 116 Os191 160

Sb124 53 As73 161

pt193 Sb125 58 162

Sc46 55 Tc97 . 163

Sc47 171 Kr87 164 r" Sc48 112 H I134 165

Se75 105 - Mn56 166 и Si31 178 - Ni65 167 Sm147 207 S 168 Sm151 86 Lower В H Er171 169

Sm153 156 S Pt197 170

• ''' Sn113 80 О Se47 171

Sn125 • 92 Q Rh105 . "172

Sr85m 234 g Np239 173

Sr85 103 Pt191 174

Sr89 62 Yb175 175

Sr90 31 Au196 176

Sr91 143 Lu177 : 177

Sr92 148 Si31 178

Ta182 54 ' Te127 179

Hg197m Tb160 70 180

Tc96m 233 T1201 • * * 181

Tc96 137 Au199 182

Tc97m Pd103 119 183

Tc97 163 Fe55 184

37 TABLE III (continued)

Radionuclides Number * indi- Radionuclides arranged Number* indi- (in alphabetical cating rank of according to their cating rank of order) radionuclides relative radiotoxicity radionuclides in the Table in the Table

Tc99m 231 ^ Ar41 185

Tc99 87 ^ Cu64 186

U T1200 je125m 104 187

Te127m 71 X Th231 188

Te127 179 О Be7 189 Lower В H 197 • Te129m 65 Hg 190

Te129 199 S Nd149 191

Te131m 124 - In115m 192

Te132 101 ^ Ru97 193

Th227 28 s Pb203 194

Th228 10 !" CI38 195

Th230 8 5 Dy165 196 Th231 188 S Cr51 197 H p 18 Th232 205 198

129 Th234 66 1 те 199

Th-Nat 204 S Kr85m 200

T1200 187 I Xe135 • ** 201

T1201 181 ? Cs131 202

2 C14 T1202 142 203

Thnat - T1204 59 204

Tm170 73 Th232 205

Tm171 108 * unat 206 • * * ц230 23 ^ Sm147 207

ц232 19 U 0238 208

ц233 26 К Nd144 . 209 O jj235 и234 27 210 H j 129 ц235 210 211

ц236 32 S In115 212 о ц238 208 -J Rb87 213

U-Nat 206 Cs135 214

у48 75 Zr93 215

38 TABLE III (continued)

Radionuclides Number * indi- Radionuclides arranged Number* indi- (in alphabetical cating rank of according to their cating rank of order) radionuclides relative radiotoxicity radionuclides in the Table in the Table

w181 107 Ni59 216

w185 106 Re187 217

w187 165 .Zn69 ' 218

Xe131m 230 Nb97" 219

In113m Xe133 228 220

Xe135 201 pt 197m 221 • ** y90 91 Cs134m 222 >• Y91m 232 H Pt193m 223

y91 64 224 о G*71 Y92 149 - H3 J 225

y93 111 O Co58m 226

Yb175 175 И Os191m 227 > ** z93 215 Э Xe133 228 О KJ.85 Zn65 81 229

Zn69m 150 Xe131m 230

Tc99m Zn69 218 231

y91m Zr95 67 232

Tc96m Zr97 87 233

Sr85m 234

Rh103m 235

Ar37 236

CONSULTANTS

Dr.G. W. DOLPHIN United Kingdom Atomic Energy Authority, Harwell

Mr. A. FAIRBAIRN United Kingdom Atomic Energy Authority, Risley, Warrington

Dr. H. JAMMET Centre d'études nucléaires, Fontenay-aux-Roses, France

Mr. L. R. ROGERS United States Atomic Energy Commission, Washington, D. C.

AGENCY STAFF MEMBERS

Dr. H. T. DAW Division of Health, Safety and (Scientific Secretary) Waste Disposal

Professor R. JAEGER Division of Isotopes

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O Rh,103 m TABLE FOR A BASIC TOXICITY CLASSIFICrASSIFICATION OF RADIONUCLIDES

ó Tc96m o oSr85"1 37 A (MPC) jjc (MPI) }J Оу91ш (MPI)£ 7.3 ИО®

Tc99m о 131m O Xe LOW Kr 85 58 m 191m .133 О о Co' OOs O Xe ,193m 69 97 n.197m r „134 m Pt ,Zn Mh J oNb о °Ge7' О I о H In 113m

Ho- 10"6—I 129 ,135 •>Te Kr85m Xe O»* о с" CI3 8 °Cr51 97 203 ,115m Ru Pb о In о ONd 149 64 200 Be7 j197 LOWER В oCu Tl 231 ,201 55 ,103 55 o Fe О Si31 Te,2Z-o о л TI" o Pd O Fe 187 ,197m 99 Re 105 Hg ? Au' ¡134 Mn56 Rh _239 3.8 *10 Ю5 Npo .177 .59 ,Ru О Lu O Ni O 65 .171 Í.171 5 8°7° °°Ni™ Er Se o Yb , .196 Kr pt191 I Au 193 -7 ; -I—P« Fp'69 •10 ho F 152h 159 ,190 «i 73 Sr92 W187 / с 153 As 220 ,92 Zn о EU Gd .. , Sm Rn222 193 97 W-O Rn O OY OQP d,10 9 О J O Pt о Тс ,-7 9 98 7.8 "Ю °Sr91 131m 47°?s"?° ТС ® A'J ;86 ° jg ,147 Os35 Oj132 ' 143 Mn®® ooo oRe Ndo 202 Re — Ce;0i M?0 9 о.. ° oAg111 Tl to72 ^ I", Prcr Dy166 .143 233 57 О Br«2_ O O o Cd 15 ооРг' О Pa' О Co 24 .122 B¡206 О Cs136 ON» •93 Sb 97m 183 93 O Y Sc4 H0B6 .141 o Tc о Re Zr -° / °°«4 »,M n 52 Ce 93 т MEDIUM 42 135 4 .74 185 181 171 93т О Nb' OK OI ¿142 О La' ® эOrТе';® OAs 105 ООО w ow o Tm О Nb' As РГ OP32 95 Ag Те125 m Se75 212 .153 ,155 135 O B¡ I О О О 125 Nb О сР О Gd О Eu O Cs у90 °Sn 3 ,.63 151 87 Zr97 Ru» Sm Rb Hg203 Zn65 2.3 «109 185 ,109 147 о O Тс99 о О V4 8 Rb»i-0 О О о 0 ooos O Cd О Pm Fe59 Со58 Sn"3 -8 91 ,29m 45 127m. i Mo' Y Te Ca ' Te 10 \ / TbwV .170 0Ba,4° SrH. ° 9 .«181 op,_ ' . O Tm o »| г 133 .125 o Tl 204 46 1l5m Hf о Oj 54 О Sb 36 Se Cd q .95 I "Mn о Cl 1.4.10,3I 228 о о Zr / Oîa182 Ас |n144mSbl24 Ir192 О °РЬ212 OBI207 OCS137 UPPER A О 131 ,126 Eu152y Na22 Ag"0m О о О Co At 211 .,210 Ru106 OOCe'44 -9 -10 LlO'- 234 ,154 OTh О Eu

129 О 1

230 Ра' 249 О O Bk

224 О Ra 10 Но1 -io- —I О 223 Sr90 О Ra 210 144 PO Nd 227 O Th 1.76 «10

и233 и234 236 235 230 242 210 О о о и O U HIGH о и О Cm О Pb 241 и238 o o О Pu Sm„14" 7 U-Nat O O 7.5 "Ю6

-1 -11 МО 10' 228 226 Th2^o O Ra 232 O Ra О U Th-Nal-^

244 O Cm

Th22 8 O Oq^ 252 OCf 250 О Cm243 О Am24' O Cm246 О I ост245 Am 243 .-12 -2 МО -10 237 O Np 227 Ac' O Th23 0 О 238 о Pu 242 240 239 242 О Pu О Pu О Pu О Pu 249 О Cf 231 О Pa

-ю -9 -13 •10 -8 -6 ,-15 -к .-12 -11 10 fi* (MPC) pg 10 10 10 10 10 10 ю J2 10 J2

-3 -2 -1 5 10"! 10~4 10 10 10 10 10 10' 10' 10' 10' 10 (MPI) Jig INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA 1963

PRICE: North America, US$1.00 Elsewhere: Sch 21,-

I6s.stg, NF 4,-; DM 3,20)