THE UNITED STATES. ENVIRONMENTAL PROTECTION AGENCY
Statutes and Legislative History
Executive Orders
Regulations
Guidelines and Reports
\
f
JANUARY 1973
WILLIAM D. RUCKELSHAUS
Administrator
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For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402
Price $6.65 per 3 volume set. Sold in sets only.
Stock Number 5500-0067
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FOREWORD
It has been said that America is like a gigantic boiler in that
once the fire is lighted, there are no limits to the power it can
generate. Environmentally, the fire has been lit!
With a mandate from the President and an aroused public
concern over the environment, we are experiencing a new Amer-
ican Revolution, a revolution in our way of life. The era which
began with the industrial revolution is over and things will never
be quite the same again. We are moving slowly, perhaps even
grudgingly at times, but inexorably into an age when social,
spiritual and aesthetic values will be prized more than production
and consumption. We have reached a point where we must bal-
ance civilization and nature through our technology.
The U.S. Environmental Protection Agency, formed by Re-
organization Plan No. 3 of 1970, was a major commitment to this
new ethic. It exists and acts in the public's name to ensure that
due regard is given to the environmental consequences of actions
by public and private institutions.
In a large measure, this is a regulatory role, one that en-
compasses basic, applied, and effects research; setting and en-
forcing standards; monitoring; and making delicate risk-benefit
decisions aimed at creating the kind of world the public desires.
The Agency was not created to harass industry or to act as a
shield behind which man could wreak havoc on nature. The
greatest disservice the Environmental Protection Agency could
do to American industry is to be a poor regulator. The environ-
ment would suffer, public trust would diminish, and instead of
free enterprise, environmental anarchy would result.
It was once sufficient that the regulatory process produce wise
and well-founded courses of action. The public, largely indifferent
to regulatory activities, accepted agency actions as being for the
"public convenience and necessity." Credibility gaps and cynicism
make it essential not only that today's decisions be wise and
well-founded but that the public know this to be true. Certitude,
not faith, is de rigueur.
In order to participate intelligently in regulatory proceedings,
the citizen should have access to the information available to the
agency. EPA's policy is to make the fullest possible disclosure of
iii
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information, without unjustifiable expense or delay, to any in-
terested party. With this in mind, the EPA Compilation of Legal
Authority was produced not only for internal operations of EPA,
but as a service to the public, as we strive together to lead the
way, through the law, to preserving the earth as a place both
habitable by and hospitable to man.
WILLIAM D. RUCKELSHAUS
Administrator
U.S. Environmental Protection Agency
IV
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PREFACE
Reorganization Plan No. 3 of 1970 transferred 15 governmental
units with their functions and legal authority to create the U.S.
Environmental Protection Agency. Since only the major laws were
cited in the Plan, the Administrator, William D. Ruckelshaus,
requested that a compilation of EPA legal authority be researched
and published.
The publication has the primary function of providing a work-
ing document for the Agency itself. Secondarily, it will serve as
a research tool for the public.
A permanent office in the Office of Legislation has been estab-
lished to keep the publication updated by supplements.
It is the hope of EPA that this set will assist in the awesome
task of developing a better environment.
MARY LANE REED WARD GENTRY, J.D.
Assistant Director for Field Operations
Office of Legislation
U.S. Environmental Protection Agency
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ACKNOWLEDGEMENT
The idea of producing a compilation of the legal authority of
EPA was conceived and commissioned by William D. Ruckelshaus,
Administrator of EPA. The production of this compilation in-
volved the cooperation and effort of numerous sources, both
within and outside the Agency. The departmental libraries at
Justice and Interior were used extensively; therefore we ex-
press our appreciation to Marvin P. Hogan, Librarian, Depart-
ment of Justice; Arley E. Long, Land & Natural Resources
Division Librarian, Department of Justice; Frederic E. Murray,
Assistant Director, Library Services, Department of the Interior.
For exceptional assistance and cooperation, my gratitude to:
Gary Baise, formerly Assistant to the Administrator, currently
Director, Office of Legislation, who first began with me on this
project; A. James Barnes, Assistant to the Administrator; K.
Kirke Harper, Jr., Special Assistant for Executive Communica-
tions; John Dezzutti, Administrative Assistant, Office of Execu-
tive Communications; Roland 0. Sorensen, Chief, Printing
Management Branch, and Jacqueline Gouge and Thomas Green,
Printing Management Staff; Ruth Simpkins, Janis Collier, Wm.
Lee Rawls, Peter J. McKenna, James G. Chandler, Jeffrey D.
Light, Randy Mott, Thomas H. Rawls, John D. Whittaker, Linda
L. Payne, Dana W. Smith, and John M. Himmelberg, a beautiful
staff who gave unlimited effort; and to many others behind the
scenes who rendered varied assistance.
MARY LANE REED WARD GENTRY, J.D.
Assistant Director for Field Operations
Office of Legislation
U.S. Environmental Protection Agency
VI
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INSTRUCTIONS
The goal of this text is to create a useful compilation of the
legal authority under which the U.S. Environmental Protection
Agency operates. These documents are for the general use of
personnel of the EPA in assisting them in attaining the pur-
poses set out by the President in creating the Agency. This work
is not intended and should not be used for legal citations or any
use other than as reference of a general nature. The author dis-
claims all responsibility for liabilities growing out of the use of
these materials contrary to their intended purpose. Moreover, it
should be noted that portions of the Congressional Record from
the 92nd Congress were extracted from the "unofficial" daily ver-
sion and are subject to subsequent modification.
EPA Legal Compilation consists of the Statutes with their
legislative history, Executive Orders, Regulations, Guidelines and
Reports. To facilitate the usefulness of this composite, the Legal
Compilation is divided into the eight following chapters:
A. General E. Pesticides
B. Air F. Radiation
C. Water G. Noise
D. Solid Waste H. International
RADIATION
The chapter labeled "Radiation" and color coded tan contains
the legal authority of the Agency as it applies to radiation pol-
lution abatement. It is well to note that any law which is appli-
cable to more than one chapter of the Compilation will appear in
each of the chapters; however, its legislative history will be cross
referenced into the "General" chapter where it is printed in full.
SUBCHAPTERS
STATUTES AND LEGISLATIVE HISTORY
For convenience, the Statutes are listed throughout the Com-
pilation by a one-point system, i.e., 1.1, 1.2, 1.3, etc., and Legisla-
tive History begins wherever a letter follows the one-point
system. Thusly, any l.la, Lib, 1.2a, etc., denotes the public laws
comprising the 1.1, 1.2 statute. Each public law is followed by its
vii
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viii INSTRUCTIONS
legislative history. The legislative history in each case consists of
the House Report, Senate Report, Conference Report (where
applicable), the Congressional Record beginning with the time
the bill was reported from committee.
Example:
1.1 1954 Atomic Energy Act, as amended, 42 U.S.C. §§2013 (d), 2021, 2051,
2073 (b), (e), 2092, 2093, 2099, 2111, 2112, 2132, 2133, 2134, 2139, 2153,
2201, 2210 (1970).
l.la Atomic Energy Act of 1946, August 1, 1946, P.L. 79-585, 60 Stat.
755.
(1) Senate Special Committee on Atomic Energy, S. REP. No.
1211, 79th Cong., 2d Sess. (1946).
(2) House Committee on Military Affairs, H.R. REP. No. 2478,
79th Cong., 2d Sess. (1946).
(3) Committee of Conference, H.R. REP. No. 2670, 79th Cong.,
2d Sess. (1946).
(4) Congressional Record, Vol. 93 (1946) :
(a) June 1: Passed Senate, pp. 6076-6098;
(b) July 16: House disagrees to Senate bill, pp. 9135-
9144;
(c) July 17, 18, 19, 20: House debates and amends Senate
bill, pp. 9249-9275, 9340-9386, 9463-9477, 9545-9563;
(d) July 22: Senate disagrees with House bill, asks for
conference, pp. 9609-9611;
This example not only demonstrates the pattern followed for
legislative history, but indicates the procedure where only one
section of a public law appears. You will note that the Congres-
sional Record cited pages are only those pages dealing with the
discussion and/or action taken pertinent to the section of law
applicable to EPA. In the event there is no discussion of the
pertinent section, only action or passage, then the asterisk (*) is
used to so indicate, and no text is reprinted in the Compilation.
In regard to the situation where only one section of a public law is
applicable, then only the parts of the report dealing with same are
printed in the Compilation.
SECONDARY STATUTES
Many statutes make reference to other laws and rather than
have this manual serve only for major statutes, these secondary
statutes have been included where practical. These secondary
statutes are indicated in the table of contents to each chapter by
a bracketed cite to the particular section of the major act which
made the reference.
CITATIONS
The United States Code, being the official citation, is used
throughout the Statute section of the Compilation.
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INSTRUCTIONS
IX
TABLE OF STATUTORY SOURCE
Statutes
1.1 1954 Atomic Energy Act, as
amended, 42 U.S.C. §§2013 (d),
2012, 2051, 2073(b), (e), 2092,
2093, 2099, 2111, 2112, 2131, 2133,
2134, 2139, 2153, 2201, 2210
(1970).
1.2 Public Health Service Act, as
amended, 42 U.S.C. §§203, 215,
241, 242(b), (c), (d), (f), (i),
(j), 243, 244, 244a, 245, 246, 247
(1970).
1.3 Public Contracts, Advertisements
for Proposals for Purchases and
Contracts for Supplies or
Services for Government Depart-
ments; Application to Govern-
ment Sales and Contracts to Sell
and to Government Corporations,
as amended, 41 U.S.C. §5 (1958).
1.4 Research and Development Act,
Contracts, as amended, 10 U.S.C.
§§2353, 2354 (1956).
1.5 International Health Research
Act, 22 U.S.C. §2101 (1960).
1.6 Per Diem, Travel and Transpor-
tation Expenses; Experts and
Consultants; Individuals Serving-
Without Pay, as amended, 5
U.S.C. §5703 (1966).
1.7 The Solid Waste Disposal Act, as
amended, 42 U.S.C. §3254f
(1970).
1.8 National Environmental Policy
Act, 42 U.S.C. §§4332(2) (c),
4344(5) (1970).
Source
Direct reference in Reorg. Plan
No. 3 of 1970.
Reorg. Plan No. 3 of 1970.
Referred to in Public Health
Service Act at §242c(e).
Referred to in Public
Service Act at §241 (h).
Health
Referenced to in the Public
Health Service Act at §242f(a).
Referenced to in Public Health
Service Act at §242f(b) (5), (6).
Section cited refers directly to
national disposal sites for storage
and disposal of hazardous waste
including radioactivity.
Reorganization Plan No. 3 of
1970.
EXECUTIVE ORDERS
The Executive Orders are listed by a two-point system (2.1, 2.2,
etc.). Executive Orders found in General are ones applying to
more than one area of the pollution chapters.
REGULATIONS
The Regulations are noted by a three-point system (3.1, 3.2,
etc.). Included in the Regulations are those not only promulgated
by the Environmental Protection Agency, but those under which
the Agency has direct contact.
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x INSTRUCTIONS
GUIDELINES AND REPORTS
This stibchapter is noted by a four-point system (4.1, 4.2, etc.).
In this subchapter is found the statutorily required reports of
EPA, published guidelines of EPA, selected reports other than
EPA's and interdepartmental agreements of note.
UPDATING
Periodically, a supplement will be sent to the interagency dis-
tribution and made available through the U.S. Government Print-
ing Office in order to provide an accurate working set of EPA
Legal Compilation.
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F. RADIATION
Volume I
Page
1. STATUTES AND LEGISLATIVE HISTORY 1
1.1 1954 Atomic Energy Act, as amended, 42 U.S.C. §§2013 (d),
2021, 2051, 2073(b), (e), 2092, 2093, 2099, 2111, 2112, 2132,
2133, 2134, 2139, 2153, 2201, 2210 (1970) 3
l.la Atomic Energy Act of 1946, August 1, 1946, P.L. 79-585,
60 Stat. 755-756, 758-766, 770-771, 774 38
(1) Senate Special Committee on Atomic Energy, S.
REP. No. 1211, 79th Cong., 2d Sess. (1946) 53
(2) House Committee on Military Affairs, H.R. REP.
No. 2478, 79th Cong., 2d Sess. (1946) 77
(3) Committee of Conference, H.R. REP. No. 2670,
79th Cong., 2d Sess. (1946) 85
(4) Congressional Record, Vol. 93 (1946):
(a) June 1: Passed Senate, pp. 6082-6085, 6087-
6088, 6094-6098 96
(b) July 16: House disagrees to Senate bill, pp.
9135-9136, 9140-9141 109
(c) July 17, 18, 19, 20: House debates and amends
Senate bill, pp. 9253-9254, 9256, 9263-9270,
9272-9275, 9343-9346, 9355-9367, 9381-9386,
9464-9470, 9552-9662 115
(d) July 22: Senate disagrees with House bill,
asks for conference, p. 9611 209
(e) July 26: House agrees to conference report,
pp. 10192-10199 209
(f) July 26: Senate agrees to conference report,
p. 10168 225
l.lb Atomic Energy Act of 1954, August 30, 1954, P.L.
83-703, §§1, 2, 3, 31, 53, 62, 63, 69, 81, 102, 103, 104, 109,
123, 161, 68 Stat. 921, 927, 930, 948 225
(1) Joint Committee on Atomic Energy, H.R. REP. No.
2181, 83rd Cong., 2d Sess. (1954) 245
(2) Joint Committee on Atomic Energy, S. REP. No.
1699, 83rd Cong., 2d Sess. (1954) 298
(3) Committee of Conference, H.R. REP. No. 2639,
83rd Cong., 2d Sess. (1954) 299
(4) Committee of Conference, H.R. REP. No. 2666,
83rd Cong., 2d Sess. (1954) 300
(5) Congressional Record, Vol. 100 (1954) :
(a) July 23, 26: Debated, passed House, pp.
11655-11656, 11683, 11688-11691,11698-11699,
11713-11715, 11731, 12025 300 '
xi
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xii CONTENTS
Page
(b) July 13-27: Debated, amended, passed Sen-
ate, pp. 10368-10370, 10484-10485, 10563-
10565, 10800-10801, 10804-10806, 10837-
10842, 11527, 11553-11554, 11568, 11826,
12132-12133, 12174, 12242 326
(c) Aug. 9: House agrees to conference report,
pp.13780-13787 376
(d) Aug. 13: Senate rejects conference report,
pp. 14338, 14340-14341, 14343-14347, 14349-
14350, 14352-14353, 14355-14356 391
(e) Aug. 16, 17: Senate and House agree to con-
ference report,' respectively, pp. 14603-14606,
14867-14873 416
l.lc Amendments to Atomic Energy Act of 1954, July 14,
1956, P.L. 84-722, 70 Stat. 553 436
(1) Joint Committee on Atomic Energy, H.R. REP.
No. 2431, 84th Cong., 2d Sess. (1956) 437
(2) Joint Committee on Atomic Energy, S. EEP. No.
2384, 84th Cong., 2d Sess. (1956) 444
(3) Congressional Record, Vol. 102 (1956):
(a) June 26: Passed House, pp. 11004-11005 452
(b) July 3: Passed Senate, p. 11719 453
l.ld 1956 Amendments to the Atomic Energy Act of 1954,
August 6, 1956, P.L. 84-1006, §§2, 3, 4, 12, 13, 70 Stat.
1069, 1071 454
(1) Joint Committee on Atomic Energy, S. REP. No.
2530, 84th Cong., 2d Sess. (1956) 455
(2) Joint Committee on Atomic Energy, H.R. REP. No.
2695, 84th Cong., 2d Sess. (1956) 459
(3) Congressional Record, Vol. 102 (1956) :
(a) July 18: Passed Senate, p. 13255 459
(b) July 26: Passed House, pp. 14888-14891 460
Lie 1957 Amendments to the Atomic Energy Act of 1954,
August 21, 1957, P.L. 85-162, Title II, §§201, 204, 71
Stat. 410 464
(1) Joint Committee on Atomic Energy, H.R. REP. No.
978, 85th Cong., 1st Sess. (1957) 465
(2) Joint Committee on Atomic Energy, S. REP. No.
791, 85th Cong., 1st Sess. (1957) 466
(3) Committee of Conference, H.R. REP. No. 1204,
85th Cong., 1st Sess. (1957) 466
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CONTENTS xiii
Volume II
Page
(4) Congressional Record, Vol. 103 (1957) :
(a) Aug. 9: Amended and passed House, p.
14261* 467
(b) Aug. 16: Amended and passed Senate, pp.
15056, 15057 467
(c) Aug. 20: Conference report submitted in Sen-
ate and agreed to, p. 15316 470
(d) Aug. 20: Conference report submitted in
House and agreed to, p. 15392 470
l.lf Amendments to the Atomic Energy Act of 1954, Sep-
tember 2, 1957, P.L. 85-256, §§2, 4, 71 Stat. 576 470
(1) Joint Committee on Atomic Energy, S. REP. No.
296, 85th Cong., 1st Sess. (1957) 474
(2) Joint Committee on Atomic Energy, S. REP. No.
435, 85th Cong., 1st Sess. (1957) 475
(3) Congressional Record, Vol. 103 (1957) :
(a) July 1: Passed House, p. 10725 475
(b) Aug. 16: Passed Senate, p. 15059* 476
(c) Aug. 19: House concurred in Senate amend-
ment, p. 15183'- 476
l.lg Amendments to the Atomic Energy Act of 1954, as
amended, September 4, 1957, P.L. 85-287, §4, 71 Stat.
613 476
(1) Joint Committee on Atomic Energy, H.R. REP.
No. 977, 85th Cong., 1st Sess. (1957) 476
(2) Joint Committee on Atomic Energy, S. REP. No.
790, 85th Cong., 1st Sess. (1957) 477
(3) Congressional Record, Vol. 103 (1957) :
(a) Aug. 26: Passed House, p. 15969 477
(b) Aug. 29: Passed Senate, p. 16496* 479
l.lh Amendments to the Atomic Energy Act of 1954, as
amended, July 2, 1958, P.L. 85-479, §§3, 4, 72 Stat. 277. 479
(1) Joint Committee on Atomic Energy, H.R. REP. No.
1849, 85th Cong., 2d Sess. (1958) 480
(2) Joint Committee on Atomic Energy, S. REP. No.
1654, 85th Cong., 2d Sess. (1958) 496
(3) Committee of Conference, H.R. REP. No. 2051,
85th Cong., 2d Sess. (1958) 497
(4) Congressional Record, Vol. 104 (1958) :
(a) June 19: Debated and passed House, pp.
11779, 11781-11782, 11784 498
(b) June 23: Amended and passed Senate, pp.
11926-11928 505
(c) June 27: Conference report submitted in
House and agreed to, p. 12560:; 510
(d) June 30: Conference report submitted in Sen-
ate and agreed to, p. 12587* 510
l.li Government Employees Training Act, July 7, 1958, P.L.
85-507, §21 (b) (1)", 72 Stat. 337 510
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xiv CONTENTS
Page
(1) Committee on Post Office and Civil Service, S. REP.
No. 213, 85th Cong., 1st Sess. (1957) 511
(2) Committee on Post Office and Civil Service, H.R.
REP. No. 1951, 85th Cong., 2d Sess. (1958) 513
(3) Congressional Record:
(a) Vol. 103 (1957), April 12: Objected to,
amended and passed Senate, pp. 5580-?5581,
5607 515
(b) Vol. 104 (1958), June 26: Amended and
passed House, p. 12384 520
(c) Vol. 104 (1958), June 27: Senate concurs with
House amendment, p. 12464.* 522
l.lj Amendment to Atomic Energy Act of 1954, as amended,
August 8, 1958, P.L. 85-602, §§2, 2[3], 72 Stat. 525. ... 522
(1) Joint Committee on Atomic Energy, S. REP. No.
1883, 85th Cong., 2d Sess. (1958) 526
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 2253, 85th Cong., 2d Sess. (1958) 530
(3) Congressional Record, Vol. 104 (1958):
(a) July 28: Passed Senate, p. 15233 530
(b) July 29: Passed House, p. 15459 531
l.lk Amendments to Atomic Energy Act of 1954, as
amended, August 19, 1958, P.L. 85-681, §§2, 4, 6, 7, 72
Stat. 632 533
(1) Joint Committee on Atomic Energy, H.R. REP.
No. 2272, 85th Cong., 2d Sess. (1958) 535
(2) Joint Committee on Atomic Energy, S. REP. No.
1944, 85th Cong., 2d Sess. (1958) 548
(3) Congressional Record, Vol. 104 (1958) :
(a) July 29: Passed House, p. 15488 549
(b) Aug. 5: Passed Senate, p. 16189.* 551
1.1J Amendments to the Atomic Energy Act of 1954, as
amended, August 23, 1958, P.L. 85-744, 72 Stat. 837. .. 551
(1) Joint Committee on Atomic Energy, H.R. REP.
No. 2250, 85th Cong., 2d Sess. (1958) 552
(2) Joint Committee on Atomic Energy, S. REP. No.
1882, 85th Cong., 2d Sess. (1958) 559
(3) Committee of Conference, H.R. REP. No. 2585,
85th Cong., 2d Sess. (1958) 560
(4) Congressional Record, Vol. 104 (1958) :
(a) July 29: Passed House, p. 15457'5 564
(b) Aug. 5: Amended and passed Senate, p. 16188 564
(c) Aug. 14: Conference report submitted in
House and agreed to, p. 17641* 564
(d) Aug. 14: Conference report submitted in Sen-
ate and agreed to, p. 17569.* 564
l.lm Amendments to the Atomic Energy Act of 1954, as
amended, September 21, 1959, P.L. 86-300, §1, 73 Stat.
574 565
(1) Joint Committee on Atomic Energy, S. REP. No.
871, 86th Cong., 1st Sess. (1959) 565
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CONTENTS xv
Page
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 1124, 86th Cong., 1st Sess. (1959) 571
(3) Congressional Record, Vol. 105 (1959) :
(a) Sept. 9: Passed Senate, p. 18732' 574
(b) Sept. 11: Passed House, p. 19169.* 574
l.ln Amendments to Atomic Energy Act of 1954, September
23, 1959, P.L. 86-373, §1, 73 Stat. 688 574
(1) Joint Committee on Atomic Energy, S. REP. No.
870, 86th Cong., 1st Sess. (1959) 579
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 1125, 86th Cong., 1st Sess. (1959) 599
(3) Congressional Record, Vol. 105 (1959) :
(a) Sept. 11: Passed Senate, pp. 19042-19046 ... 614
(b) Sept. 11: Passed House, pp. 19169-19170. ... 622
l.lo Amendment to Atomic Energy Act of 1954, as amended,
September 6, 1961, P.L. 87-206, §§13, 15, 75 Stat. 478. . 625_
(1) Joint Committee on Atomic Energy, H.R. REP. No.
963, 87th Cong-., 1st Sess. (1961) 625
(2) Joint Committee on Atomic Energy, S. REP. No.
746, 87th Cong., 1st Sess. (1961) 632
(3) Congressional Record, Vol. 107 (1961) :
(a) Aug. 22: Passed House, p. 16611s- 633
(b) Aug. 24: Passed Senate, p. 16957.* 633
l.lp To Amend the Tariff Act of 1930, and Certain Related
Laws, May 24, 1962, P.L. 87-456, Title III, §303 (c), 76
Stat. 78 633
(1) House Committee on Ways and Means, H.R. REP.
No. 1415, 87th Cong., 2d Sess. (1962) 634
(2) Senate Committee on Finance, S. REP. No. 1317,
87th Cong., 2d Sess. (1962) 635
(3) Congressional Record, Vol. 108 (1968) :
(a) March 14: Passed House, p. 4067'5 635
(b) April 17: Amended and passed Senate, p.
6794* 635
(c) May 9: House concurs with Senate amend-
ment, p. 8010.* 636
l.lq To Amend the Atomic Energy Act of 1954, as amended,
August 29, 1962, P.L. 87-615, §§6, 7, 9, 12, 76 Stat. 410. 636
(1) Joint Committee on Atomic Energy, S. REP. No.
1677, 87th Cong., 2d Sess. (1962) 637
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 1966, 87th Cong., 2d Sess. (1962) 642
(3) Congressional Record, Vol. 108 (1962) :
(a) Aug. 7: Passed Senate, p. 15746 643
(b) Aug. 15: Passed House, p. 16551.* 645
l.lr To Adjust Postal Rates, October 11, 1962, P.L. 87-793,
§1001 (g), 76 Stat. 864 645
(1) House Committee on Post Office and Civil Service,
H.R. REP. No. 1155, 87th Cong., 1st Sess. (1961). 646
(2) Senate Committee on Post Office and Civil Service,
S. REP. No. 2120, 87th Cong., 2d Sess. (1962). ... 647
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xvi CONTENTS
Page
(3) Committee of Conference, H.R. REP. No. 2525,
87th Cong., 2d Sess. (1962) 648
(4) Committee of Conference, H.R. REP. No. 2532,
87th Cong., 2d Sess. (1962) 649
(5) Congressional Record, Vol. 108 (1962):
(a) Jan. 24: Passed House, p. 827* 650
(b) Sept. 27: Amended and passed Senate, p.
21014* 650
(c) Oct. 3: Senate agrees to conference report,
p. 22027* 650
(d) Oct. 4: Senate agrees to conference report,
p. 22232* 650
(e) Oct. 5: House agrees to conference report,
p. 22602 650
l.ls To Amend the Atomic Energy Act of 1954, as amended,
August 1, 1964, P.L. 88-394, §§2, 3, 78 Stat. 376 652
(1) Joint Committee on Atomic Energy, S. REP. No.
1128, 88th Cong., 2d Sess. (1964) 653
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 1525, 88th Cong., 2d Sess. (1964) 660
(3) Congressional Record, Vol. 110 (1964) :
(a) July 8: Debated, passed Senate, pp. 16100-
16101 664
(b) July 21: Debated, passed House, pp. 16474,
16476, 16478-16479 667
l.lt 1964 Amendments to the Atomic Energy Act of 1954,
August 26, 1964, P.L. 88-489, §§3, 5-8, 15, 16, 78 Stat.
602 670
(1) Joint Committee on Atomic Energy, S. REP. No.
1325, 88th Cong., 2d Sess. (1964) 674
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 1702, 88th Cong., 2d Sess. (1964) 682
** (3) Congressional Record, Vol. 110 (1964) :
(a) Aug. 6: Passed Senate, p. 18434* 684
(b) Aug. 18: Passed House, p. 20145.* 684
l.lu To Amend Section 170 of the Atomic Energy Act of
1954, as amended, September 29, 1965, P.L. 89-210,
§§1-5, 79 Stat. 855 684
(1) Joint Committee on Atomic Energy, S. REP. No.
650, 89th Cong., 1st Sess. (1965) 687
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 883, 89th Cong., 1st Sess. (1965) 711
(3) Congressional Record, Vol. Ill (1965) :
(a) Aug. 31: Passed Senate, p. 22281* 711
(b) Sept. 16: Debated and passed House, pp.
24035-24049 711
l.lv To Amend the Atomic Energy Act of 1954, as amended,
October 13, 1966, P.L. 89-645, §§1 (b), 2, 3, 80 Stat. 891. 742
(1) Joint Committee on Atomic Energy, S. REP. No.
1605, 89th Cong., 2d Sess. (1966) 745
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 2043, 89th Cong., 2d Sess. (1966) 788
(3) Congressional Record, Vol. 112 (1966) :
(a) Sept. 22: Passed Senate, pp. 23633-23634 .... 789
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CONTENTS xvii
Page
(b) Sept. 30: Passed House, pp. 24635-24637. ... 792
l.lw To Amend the Atomic Energy Act of 1954, as amended,
December 14, 1967, P.L. 90-190, §§9,10, 11, 81 Stat. 577. 798
(1) Joint Committee on Atomic Energy, S. REP. No.
743, 90th Cong., 1st Sess. (1967) 800
(2) Joint Committee on Atomic Energy, H.R. REP.
No. 911, 90th Cong., 1st Sess. (1967) 809
(3) Congressional Record, Vol. 113 (1967) :
(a) Nov. 15: Passed Senate, p. 32583* 810
(b) Nov. 30: Passed House, pp. 34398-34399,
34403 810
l.lx Atomic Energy Act Amendments, December 19, 1970,
P.L. 91-560, §§1, 4, 5, 7, 8, 84 Stat. 1472, 1474 816
(1) Joint Committee on Atomic Energy, H.R. REP.
No. 91-1470, 91st Cong., 2d Sess. (1970) 817
(2) Joint Committee on Atomic Energy, S. REP. No.
91-1247, 91st Cong., 2d Sess. (1970) 868
(3) Congressional Record, Vol. 116 (1970) :
(a) Sept. 30: Considered and passed House, pp.
H9442, H9452 869
(b) Dec. 2: Considered, amended and passed Sen-
ate, pp. S19252-S19257 895
(c) Dec. 3: House agrees to Senate amendments,
pp. H11086-H11087 908
l.ly Atomic Energy Commission Appropriation Authori-
zation, August 11, 1971, P.L. 92-84, Title II, §201, 85
Stat. 307 911
(1) Joint Committee on Atomic Energy, H.R. REP.
No. 92-325, 92d Cong., 1st Sess. (1971) 911
(2) Joint Committee on Atomic Energy, S. REP. No.
92-249, 92d Cong., 1st Sess. (1971) 913
(3) Congressional Record, Vol. 117 (1971) :
(a) July 15: Considered and passed House, pp.
H6764, H6801 914
(b) July 20: Considered and passed Senate,
amended, p. S11502' 914
(c) July 27: House concurred in Senate amend-
ments with amendment, p. H7189;- 914
(d) July 31: Senate concurred in House amend-
ment, p. S12694.'' 914
1.2 Public Health Service Act, as amended, 42 U.S.C. §§203,
215, 241, 242b, 242c, 242d, 242f, 242i, 242j, 243, 244, 244a,
245, 246, 247 (1970) 915
(See, "General 1.12a-1.12ah" for legislative history)
1.3 Public Contracts, Advertisements for Proposals for Pur-
chases and Contracts for Supplies or Services for Govern-
ment Departments; Application for Government Sales and
Contracts to Sell and to Government Corporations, as
amended, 41 U.S.C. §5 (1958) 946
[Referred to in 42 U.S.C. §242c(e)]
(See, "General 1.14a-1.14c" for legislative history)
1.4 Research and Development Act, Contracts, as amended, 10
U.S.C. §§2353, 2354 (1965) 947
[Referred to in 42 U.S.C. §241 (h)]
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xviii CONTENTS
Volume III
Page
1.4a Armed Forces Research and Development, July 16,
1952, P.L. 82-577, §§4, 5, 66 Stat. 725 949
(1) House Committee on Armed Services, H.R. REP.
No. 548, 82d Cong., 1st Sess. (1951) 951
(2) Senate Committee on Armed Services, S. REP.
No. 936, 82d Cong., 1st Sess. (1951) 952
(3) Congressional Record:
(a) Vol. 97 (1951), Aug. 2: Passed House, p.
9433 955
(b) Vol. 98 (1952), July 3: Amended and passed
Senate, pp. 9053-9054* 955
(c) Vol. 98 (1952), July 4: House concurs in
Senate amendments, pp. 9374-9375.* 955
1.4b Armed Services Procurement Amendments of 1956,
August 10, 1956, P.L. 84-1028, §§2353, 2354, 70A
Stat. 134 955
(1) House Committee on the Judiciary. H.R. REP.
No. 970, 84th Cong., 1st Sess. (1955) 957
(2) Senate Committee on the Judiciary, S. REP. No.
2484, 84th Cong., 2d Sess. (1956) 960
(3) Congressional Record:
(a) Vol. 101 (1955), Aug. 1: Amended and
passed House, pp. 12718-12719* 962
(b) Vol. 102 (1956), July 23: Amended and
passed Senate, p. 13953* 962
(c) Vol. 102 (1956), July 25: House concurs in
Senate amendments, p. 14455.* 962
1.5 International Health Research Act, 22 U.S.C. §2101 (1960). 963
[Referred to in 42 U.S.C. §242f (a)]
1.5a Foreign Assistance Act of 1961, September 4, 1961,
P.L. 87-195, Pt. I, §241, 75 Stat. 433 964
(1) Senate Committee on Foreign Relations, S. REP.
No. 612, 87th Cong., 1st Sess. (1961) 964
(2) House Committee on Foreign Affairs, H.R. REP.
No. 851, 87th Cong., 1st Sess. (1961) 965
(3) Committee of Conference, H.R. REP. No. 1088,
87th Cong., 1st Sess. (1961) 971
(4) Congressional Record, Vol. 107 (1961):
(a) Aug. 16: Passed Senate, p. 16411* 972
(b) Aug. 17: Amended and passed House, p.
16501* 972
(c) Aug. 31: Senate agrees to conference re-
port, p. 17712* 972
(d) Aug. 31: House agrees to conference re-
port, p. 17862.* 972
1.5b Foreign Assistance Act of 1963, December 16, 1963,
P.L. 88-205, Pt. I, §105, 77 Stat. 382 972
(1) House Committee on Foreign Affairs, H.R. REP.
No. 646, 88th Cong., 1st Sess. (1963) 973
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CONTENTS xix
Page
(2) Senate Committee on Foreign Relations, S. REP.
No. 588, 88th Cong., 1st Sess. (1963) 973
(3) Committee of Conference, H.R. REP. No. 1006,
88th Cong., 1st Sess. (1963) 975
(4) Congressional Record, Vol. 109 (1963) :
(a) Aug. 23: Passed House, p. 15678* 976
(b) Oct. 24, Nov. 15: Debated, amended and
passed Senate, p. 21978 976
(c) Dec. 9: Conference report submitted in
House and agreed to, p. 23850 * 977
(d) Dec. 13: Conference report agreed to in
Senate, pp. 24453-24454 977
1.6 Per Diem, Travel and Transportation Expenses; Experts
and Consultants; Individuals Serving Without Pay, as
amended, 5 U.S.C. §5703 (1966) 979
[Referred to in 42 U.S.C. §242f(b) (5), (6)]
(See, "General 1.15a-1.15d(3) (c)" for legislative history)
1.7 The Solid Waste Disposal Act, as amended, 42 U.S.C.
§3254f (1970) 980
1.7a The Resource Recovery Act of 1970, October 26, 1970,
P.L. 91-512, Title I, §104 (b), 84 Stat. 1233 981
(1) House Committee on Interstate and Foreign Com-
merce, H.R. REP. No. 91-1155, 91st Cong., 2d
Sess. (1970) 982
(2) Senate Committee on Public Works, S. REP. No.
91-1034, 91st Cong., 2d Sess. (1970) 983
(3) Committee of Conference, H.R. REP. No. 91-
1579, 91st Cong., 2d Sess. (1970) 985
(4) Congressional Record, Vol. 116 (1970) :
(a) June 23: Passed House, p. 20893* 986
(b) Aug. 3: Considered, amended and passed
Senate, p. 26942* 986
(c) Oct. 7: Senate agreed to conference report,
pp. 35511, 35516* 986
(d) Oct. 13: House agreed to conference report
p. 36587.* 986
1.8 National Environmental Policy Act of 1969, 42 U.S.C.
§§4332(2) (c), 4344(5) (1970) 987
(See, "General 1.2a-1.2a(4) (e)" for legislative history)
2. EXECUTIVE ORDERS 989
2.1 E.G. 10831, Establishment of the Federal Radiation Council,
August 14, 1959, 24 Fed. Reg. 6669 (1959) 991
3. REGULATIONS 993
EPA's Office of Radiation Programs has not promulgated any
regulations. Guidelines for Uranium Miner Exposure are found
under the "Guidelines and Reports" section. Reorganization Plan
No. 3 of 1970 transferred to EPA certain powers previously held
by the Atomic Energy Commission. EPA is currently establish-
ing a viable "interface" with the AEC. AEC regulations which
EPA is reviewing are those that deal with releases of radiation
to the environment and are currently found under Title 10 of the
-------
xx CONTENTS
Page
Code of Federal Regulations. Chapters of particular interest
are ch. 20 ("Standards for Protection Against Radiation"), and
ch. 30 ("Rules of General Applicability to Licensing of Byprod-
uct Material") 995
4. GUIDELINES AND REPORTS 997
4.1 Background Material for the Development of Radiation Pro-
tection Standards, Staff Report of the Federal Radiation
Council 999
4.1a Background Material for the Development of Radiation
Protection Standards, Report No. 1, Staff Report of the
Federal Radiation Council, May 13, 1960 999
4.1a(l) Radiation Protection Guidance for Federal
Agencies (Memorandum for the President),
Federal Radiation Council, May 18, 1960, 25
Fed. Reg. 4402 (1960) 1053
4.1b Background Material for the Development of Radiation
Protection Standards, Report No. 2, Staff Report of the
Federal Radiation Council, September 1961 1059
4.1b(l) Radiation Protection Guidance for Federal
Agencies (Memorandum for the President),
Federal Radiation Council, September 26, 1961,
26 Fed. Reg. 9057 (1961) 1087
4.1c Health Implications of Fallout From Nuclear Weapons
Testing Through 1961, Report No. 3 of the Federal
Radiation Council, May 1962 1093
4. Id Estimates and Evaluation of Fallout in the United
States from Nuclear Weapons Testing Conducted
Through 1962, Report No. 4 of the Federal Radiation
Council, May 1963 1100
4.1e Background Material for the Development of Radiation
Protection Standards, Report No. 5, Staff Report of the
Federal Radiation Council, July 1964 1134
4.1e(l) Radiation Protection Guidance for Federal
Agencies (Memorandum to the President),
Federal Radiation Council, August 22, 1964, 29
Fed. Reg. 12056 (1964) 1149
4.If Revised Fallout Estimates for 1964-65 and Verification
of the 1963 Predictions, Report No. 6, Staff Report of
the Federal Radiation Council, May 1965 1152
4.1g Background Material for the Development of Radiation
Protection Standards, Protective Action Guides for
Strontium-89, Strontium-90 and Cesium-137, Report
No. 7, Staff Report of the Federal Radiation Council,
May 1965 1174
4.1g(l) Radiation Protection Guidance for Federal
Agencies (Memorandum to the President),
Federal Radiation Council, May 22, 1965, 30
Fed. Reg. 6953 (1965) 1212
4.1h Guidance for the Control of Radiation Hazards in Ura-
nium Mining, Report No. 8, Staff Report of the Federal
Radiation Council, September 1967 1221
-------
CONTENTS xxi
Page
4.1h(l) Radiation Protection Guidance for Federal
Agencies (Memorandum to the President),
Federal Radiation Council, August 1, 1967, 32
Fed. Reg. 11183 (1967) 1273
4.2 Selected Reports 1277
4.2a Pathological Effects of Thyroid Irradiation, Federal
Radiation Council, Revised Report—December 1966. 1277
4.2b Radiation Exposure of Uranium Miners, Report of an
Advisory Committee from the Division of Medical
Sciences: National Academy of Sciences—National
Research Council—National Academy of Engineering,
Federal Radiation Council, August 1968 1292
4.2c Implication to Man of Irradiation by Internally De-
posited Strontium-89, Strontium-90, and Cesium-137,
Report of an Advisory Committee from the Division of
Medical Sciences: National Academy of Sciences—
National Research Council, Federal Radiation Council,
December 1964 1324
4.2d An Estimate of Radiation Doses Received by Individ-
uals Living in the Vicinity of a Nuclear Reprocessing
Plant in 1968, Department of Health, Education, and
Welfare, May 1970 1362
4.2e Liquid Waste Effluents from a Nuclear Fuel Reprocess-
ing Plant, Department of Health, Education, and Wel-
fare, November 1970 1380
4.3 Uranium Miners Exposure Guidelines 1419
4.3a Radiation Protection Guidelines, Federal Radiation
Council, January 15, 1969, 34 Fed. Reg. 576 (1969). . . 1419
4.3b Radiation Protection Guidelines, Federal Radiation
Council, December 18, 1970, 35 Fed. Reg. 19218 (1970). 1420
4.3c Radiation Protection Guidance, Underground Mining
of Uranium Ore, Environmental Protection Agency,
May 25, 1971, 36 Fed. Reg. 9480 (1971) 1422
4.3d Radiation Protection Guidance, Underground Mining
of Uranium Ore, Environmental Protection Agency,
July 9, 1971, 36 Fed. Reg. 1292 (1971) 1430
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STATUTES AND LEGISLATIVE HISTORY 949
1.4a ARMED FORCES RESEARCH AND DEVELOPMENT
July 16,1952, P.L. 82-557, §§4, 5,66 Stat. 725
SEC. 4. Any contract of the military departments for research
or development, or both, may provide for the acquisition or con-
struction by, or furnishing to, the contractor of such research,
developmental, or test facilities and equipment as may be de-
termined by the Secretary concerned to be necessary for the per-
formance thereof. Such research, developmental, or test facilities
and equipment, including specialized housing therefor, may be
acquired or constructed at Government expense, and may be
furnished to the contractor by lease, loan, or sale at fair value,
and with or without reimbursement to the Government for the use
thereof: Provided, That nothing contained in this subsection shall
be deemed to authorize new construction or improvements having
general utility: Provided further, That nothing contained herein
shall be deemed to authorize the installation or construction of
facilities on property not owned by the Government which would
not be readily removable or separable without unreasonable ex-
pense or unreasonable loss of value, unless adequate provision is
made in the contract for (1) reimbursement to the Government of
the fair value of such facilities upon the completion or termination
of the contract, or within a reasonable time thereafter, or (2) an
[p. 725]
option in the Government to acquire the underlying land, or (3)
such other provisions as will in the opinion of the Secretary con-
cerned be adequate to protect the Government's interest in such
facilities: And provided further, That all moneys arising from
sales or reimbursement under this section shall be covered into the
Treasury as miscellaneous receipts, except to the extent otherwise
authorized by law with respect to contractor-acquired property.
The Secretary of each of the military departments shall transmit
to the Congress reports covering contracts for research or develop-
ment entered into during each six months following the enactment
of this Act. Each such report shall contain (1) a list of each
contract for research or development entered into during such pe-
riod the total cost of which to the Government will exceed $50,000,
and (2) specific information with respect to each such contract,
except that specific information the disclosure of which he deems
incompatible with the security of the United States may be ex-
cluded from such reports.
SEC. 5. With the approval of the Secretary concerned, any con-
tract of the military departments for research or development, or
-------
950 LEGAL COMPILATION—RADIATION
both, may provide that the Government will indemnify the con-
tractor against either or both of the following, to the extent that
they arise out of the direct performance of said contract and are
not compensated by insurance or otherwise: (1) Liability on ac-
count of claims (including reasonable expenses of litigation or
settlement of such claims) by third persons, including employees
of the contractor, for death, bodily injury, or loss of or damage to
property, arising- as a result of a risk denned in the contract to be
unusually hazardous: [Provided, That any contract so providing
shall also contain appropriate provisions for notice to the Govern-
ment of suits or actions filed or claims made, against the contrac-
tor, with respect to any alleged liability for such death, bodily
injury, or loss of or damage to property, and for control of or
assistance in the defense of any such suit, action, or claims, by the
Government, at its election;] and (2) loss of or damage to property
of the contractor arising as a result of a risk defined in the contract
to be unusually hazardous: And provided further, That no pay-
ment shall be made by the Government under authority of this
section unless the amount thereof shall first have been certified to
be just and reasonable by the Secretary concerned or by an official
of the department designated for such purpose by the Secretary.
Any such payment may be made, with the approval of the Secre-
tary concerned, out of any funds obligated for the performance of
such contract or out of funds available for research and develop-
ment work and not otherwise obligated; or out of any funds ap-
propriated by the Congress for the making of such payments.
[p. 726]
-------
STATUTES AND LEGISLATIVE HISTORY 951
1.4a(l) HOUSE COMMITTEE ON ARMED SERVICES
H.R. REP. No. 548, 82d Cong., 1st Sess. (1951)
FACILITATING THE PERFORMANCE OF RESEARCH AND
DEVELOPMENT WORK BY AND ON BEHALF OF THE
DEPARTMENTS OF THE ARMY, NAVY, AND AIR FORCE
JUNE 12, 1951.—Committed to the Committee of the Whole House on the State
of the Union and ordered to be printed
Mr. HEBERT, from the Committee on Armed Services, submitted
the following
REPORT
[To accompany H.R. 1180]
The Committee on Armed Services, to whom was referred the
bill (H.R. 1180) to facilitate the performance of research and de-
velopment work by and on behalf of the Departments of the Army,
the Navy, and the Air Force, and for other purposes, having con-
sidered the same, report favorably thereon without amendment
and recommend that the bill do pass.
The purpose of the proposed legislation is to provide the armed
services with powers which are considered to be necessary to fa-
cilitate the carrying on of their research and development pro-
grams.
[p. 1]
SECTIONAL ANALYSIS
Section 4 provides for the furnishing of necessary research,
developmental or test facilities to contractors, subject to adequate
protection of the Government's interests therein. It is the com-
mittee's understanding that, under the provisions of this section,
the military departments may utilize research and development
funds for the furnishing or construction of equipment or facilities
for the use of contractors where appropriate. Wartime experience
indicates that situations arise in which contractors require special
facilities for the performance of their contracts. Since in many
cases these facilities would be of no use to them apart from the
performance of such contracts, they are unable to provide the fa-
-------
952 LEGAL COMPILATION—RADIATION
cilities at their own expense. On the other hand, to permit con-
tract prices to include sufficient amounts to cover the cost of such
facilities, would obviously be unfair to the Government in that the
Government would, in effect, be not only buying the facilities, but
would then leave them in the possession of the contractor. The
solution proposed herein is to authorize the Government to provide
such facilities, at the same time protecting its interest therein.
Section 5 provides authority for the military departments to
agree to indemnify contractors against liability and loss resulting
from injury to persons or damage to property arising out of the
direct performance of a research and development contract, to the
extent that such losses are not compensated by insurance or other-
wise. In many cases, contractors are reluctant to undertake a re-
search or development contract involving extremely hazardous
new developments without adequate protection in the event of
liability resulting from claims made as a result of damage from
those experiments. No provision can be made
[p. 3]
for such protection by including a reserve in the contract price,
and the cost of insurance, if at all obtainable, would be prohibitive.
The solution is for the Government to agree to indemnify such a
contractor subject to the safeguards provided in this section.
[p. 4]
-------
STATUTES AND LEGISLATIVE HISTORY 953
1.4a(2) SENATE COMMITTEE ON ARMED SERVICES
S. REP. No. 936, 82d Cong., 1st Sess. (1951)
FACILITATING THE PERFORMANCE OF RESEARCH AND
DEVELOPMENT WORK BY AND ON BEHALF OF THE
DEPARTMENTS OF THE ARMY, THE NAVY, AND THE
AIR FOPvCE
OCTOBER 11 (legislative day, OCTOBER 1), 1951.—Ordered to be printed
Mr. STENNIS, from the Committee on Armed Services, submitted
the following
REPORT
[To accompany H.R. 1180]
The Committee on Armed Services, to whom was referred the
bill H.R. 1180, to facilitate the performance of research and de-
velopment work by and on behalf of the Departments of the Army,
the Navy, and the Air Force, and for other purposes, having con-
sidered the same, report favorably thereon, without amendments,
and recommend that the bill do pass.
PURPOSE OF THE BILL
The proposed legislation would provide the three military de-
partments with certain administrative authority required to carry
out their research and development programs.
[p. 1]
EXPLANATION OF BILL
Major provisions of the bill
The more important administrative powers which the bill pro-
vides are listed below:
;I: j|c sjs % $ % *
(4) The furnishing of Government facilities;
(5) The indemnification against damage loss, where the con-
tractor is unable to procure insurance coverage;
[p. 2]
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954 LEGAL COMPILATION—RADIATION
SECTION-BY-SECTION ANALYSIS
Section 4- Furnishing of certain essential facilities to contractors
This section provides for the furnishing of necessary research,
developmental or test facilities to contractors, subject to adequate
protection of the Government's interests therein. Under the pro-
visions of this section, the military departments may utilize re-
search and development funds for the furnishing or construction
of equipment or facilities for the use of contractors where ap-
propriate. Wartime experience indicates that situations arise in
which contractors require special facilities for the performance
of their contracts. Since in many cases these facilities would be
of no use to them apart from the performance of such contracts,
they are unable to provide the facilities at their own expense. On
the other hand, to permit contract prices to include sufficient
amounts to cover the cost of such facilities, would obviously be
unfair to the Government in that the Government would,
[p. 3]
in effect, be not only buying the facilities, but would then leave
them in the possession of the contractor. The solution proposed
herein is to authorize the Government to provide such facilities,
at the same time protecting its interest therein.
Section 5. Authority to indemnify contractors against liability
and loss arising from injury or damage
This section provides authority for the military departments to
agree to indemnify contractors against liability and loss resulting
from injury to persons or damage to property arising out of the
direct performance of a research and development contract, to the
extent that such losses are not compensated by insurance or other-
wise. In many cases, contractors are reluctant to undertake a
research or development contract involving extremely hazardous
new developments without securing adequate protection in the
event of liability resulting from claims made as a result of damage
from those experiments. No provision can be made for such pro-
tection by including a reserve in the contract price and the cost of
insurance, if at all obtainable, would be prohibitive. The solution
is for the Government to agree to indemnify such a contractor,
subject to the safeguards provided in this section.
[p. 4]
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STATUTES AND LEGISLATIVE HISTORY
955
1.4a(3) CONGRESSIONAL RECORD
1.4a(3)(a) VOL. 97 (1951), Aug. 2: Passed House, p. 9433
Mr. HEBERT.
jjc -|: >\i :]; ^t
The most important feature of the bill
is that section which in effect indemni-
fies private contractors who are con-
tracted to the Government to conduct
these experimental features. I may
point out the necessity for this is
pointed up perhaps in the development
of the supersonic plane by the Bell Air-
plane Co. In that particular instance
it was impossible to indemnify a civil-
ian test pilot, and an Army lieutenant
was used to fly that ship on its first
flight.
[p. 9433]
1.4a(3)(b) VOL. 98 (1952), July 3: Amended and passed Senate, pp.
9053-9054
[No Relevant Discussion on Pertinent Section]
1.4a(3)(c) VOL. 98 (1952), July 4: House concurs in Senate amend-
ments, pp. 9374-9475
[No Relevant Discussion on Pertinent Section]
1.4b ARMED SERVICES PROCUREMENT AMENDMENTS OF
1956
August 10,1956, P.L. 84-1028, §§2353, 2354, 70A Stat. 134
§2353. Contracts: acquisition, construction, or furnishing of test facil-
ities and equipment
(a) A contract of a military department for research or devel-
opment, or both, may provide for the acquisition or construction
by, or furnishing to, the contractor, of research, developmental, or
test facilities and equipment that the Secretary of the military de-
partment concerned determines to be necessary for the perform-
ance of the contract. The facilities and equipment, and specialized
housing for them, may be acquired or constructed at the expense
of the United States, and may be lent or leased to the contractor
with or without reimbursement, or may be sold to him at fair
value. This subsection does not authorize new construction or im-
provements having general utility.
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956 LEGAL COMPILATION—RADIATION
(b) Facilities that would not be readily removable or separable
without unreasonable expense or unreasonable loss of value may
not be installed or constructed under this section on property not
owned by the United States, unless the contract contains—
(1) a provision for reimbursing the United States for the
fair value of the facilities at the completion or termination of
the contract or within a reasonable time thereafter;
(2) an option in the United States to acquire the underly-
ing land; or
(3) an alternative provision that the Secretary concerned
considers to be adequate to protect the interests of the United
States in the facilities.
(c) Proceeds of sales or reimbursements under this section
shall be paid into the Treasury as miscellaneous receipts, except
to the extent otherwise authorized by law with respect to property
acquired by the contractor.
§2354. Contracts: indemnification provisions
(a) With the approval of the Secretary of the military depart-
ment concerned, any contract of a military department for re-
search or development, or both, may provide that the United States
will indemnify the contractor against either or both of the fol-
lowing, but only to the extent that they arise out of the direct per-
formance of the contract and to the extent not compensated by
insurance or otherwise:
(1) Claims (including reasonable expenses of litigation or
settlement) by third persons, including employees of the con-
tractor, for death, bodily injury, or loss of or damage to prop-
erty, from a risk that the contract defines as unusually
hazardous.
(2) Loss of or damage to property of the contractor from a
risk that the contract defines as unusually hazardous.
(b) A contract, made under subsection (a), that provides for
indemnification must also provide for—
(1) notice to the United States of any claim or suit against
the contractor for the death, bodily injury, or loss of or dam-
age to property; and
(2) control of or assistance in the defense by the United
States, at its election, of that suit or claim.
(c) No payment may be made under subsection (a) unless the
Secretary of the department concerned, or an officer or official of
his department designated by him, certifies that the amount is just
and reasonable.
[p. 134]
-------
STATUTES AND LEGISLATIVE HISTORY 957
(d) Upon approval by the Secretary concerned, payments under
subsection (a) may be made from—
(1) funds obligated for the performance of the contract
concerned;
(2) funds available for research or development, or both,
and not otherwise obligated; or
(3) funds appropriated for those payments.
[p. 135]
1.4b(l) HOUSE COMMITTEE ON THE JUDICIARY
H.R. REP. No. 970, 84th Cong., 1st Sess. (1955)
REVISION OF TITLE 10, U. S. CODE, ENTITLED "ARMED
FORCES", AND TITLE 32, U. S. CODE, ENTITLED "NA-
TIONAL GUARD"
JUNE 28, 1955.—Committed to the Committee of the Whole House on the State
of the Union ordered to be printed
Mr. WILLIS, from the Committee on the Judiciary, submitted the
following
REPORT
[To accompany H.R. 7049]
The Committee on the Judiciary, to whom was referred the bill
(H.R. 7049) to revise, codify, and enact into law title 10 of the
United States Code, entitled "Armed Forces", and title 32, United
States Code, entitled "National Guard", having considered the
same, report favorably thereon and recommend that the bill do
pass.
I. EXPLANATION OF REVISED TITLE 10, ARMED FORCES,
AND TITLE 32, NATIONAL GUARD
1. PURPOSE AND HISTORY
The Constitution, in article I, section 8, lists among the powers
of Congress the powers "To raise and support Armies" and "To
provide and maintain a Navy". In the exercise of these powers,
-------
958 LEGAL COMPILATION—RADIATION
Congress has enacted hundreds of laws regulating the structure of
the armed forces and the functioning of its members, in some cases
down to the smallest detail.
These laws have been enacted over a long period extending from
1789 to the present date. They have been drawn by many drafts-
men, some good, some poor, and some indifferent. Even where
laws have been excellently drawn, they often reflect inconsistent
approaches and means of expression. The result has been laws
full of contradictions, duplications, ambiguities, obscurities, and
obsolete provisions. This problem has existed not only for the
armed forces but the Government as a whole.
[p. 1]
SECTION 2353
Revised
Section Source (U.S. Code) Source (Statutes at Large)
2353 (a) 5:235e (1st sentence; and July 16, 1952, ch. 882, §4 (less 3d
2d sentence, less 2d and and last sentences), 66 Stat. 725.
last provisos)
5:475j (1st sentence; and
2d sentence, less 2d and
last provisos)
5:628e (1st sentence; and
2d sentence, less 2d and
last provisos)
2353 (b) 5:235e (2d proviso of 2d
sentence)
5:475j (2d proviso of 2d
sentence)
5:628e (2d proviso of 2d
sentence)
2353 (c) 5:235e (last proviso of 2d
sentence)
5:475j (last proviso of 2d
sentence)
5:628e (last proviso of 2d
sentence)
In subsection (a), the words "furnished to" and "for the use
thereof" are omitted as surplusage.
In subsections (a) and (b), the words "United States" are sub-
stituted for the word "Government".
In subsection (b), the introductory clause is substituted for
5:235e (words of 2d proviso before clause (1)), 475j, and 628e.
The words "that. . . considers" are substituted for the words "as
will in the opinion". The words "an alternative" are substituted
for the words "such other".
In subsection (c), the words "Proceeds of" are substituted for
the words "That all moneys arising from".
-------
STATUTES AND LEGISLATIVE HISTORY 959
SECTION 2354
Revised
Section Source (U.S. Code) Source (Statutes at Large)
2354 (a) 5:235f (1st sentence, less July 16, 1952, ch. 882, §5, 66 Stat.
provisos) 726.
5:475k (1st sentence, less
provisos)
5:628f (1st sentence, less
provisos)
2354 (b) 5:235f (1st proviso of 1st
sentence)
5:475k (1st proviso of 1st
sentence)
5 :628f (1st proviso of 1st
sentence)
2354 (c) 5:235f (last proviso of
1st sentence)
5:475k (last proviso of
1st sentence)
5:628f (last proviso of
1st sentence)
2354 (d) 5:235f (less 1st sentence)
5:475k (less 1st sentence)
5:628f (less 1st sentence)
In subsection (a), the words "Liability on account of", and "of
such claims" are omitted as surplusage. In clauses (1) and (2),
the word "from" is substituted for the words "arising as a result
of".
[p. 139]
-------
960 LEGAL COMPILATION—KADIATION
1.4b(2) SENATE COMMITTEE ON THE JUDICIARY
S. REP. No. 2484, 84th Cong., 2d Sess. (1956)
REVISION OF TITLE 10, UNITED STATES CODE, EN-
TITLED "ARMED FORCES", AND TITLE 32, UNITED
STATES CODE, ENTITLED "NATIONAL GUARD"
JULY 9, 1956.—Ordered to be printed
Mr. O'MAHONEY, from the Committee on the Judiciary, submitted
the following
REPORT
[To accompany H.R. 7049]
The Committee on the Judiciary, to which was referred the bill
(H.R. 7049) to revise, codify, and enact into law title 10 of the
United States Code, entitled "Armed Forces", and title 32 of the
United States Code, entitled "National Guard", having considered
the same, reports favorably thereon with amendments and recom-
mends that the bill, as amended, do pass.
[p. 1]
-------
STATUTES AND LEGISLATIVE HISTORY 961
SECTION 2353
Revised
Section Source (U.S. Code) Source (Statutes at Large)
2353 (a) 5:235e (1st sentence; and July 16, 1952, ch. 882, §4 (less 3d
2d sentence, less 2d and and last sentences), 66 Stat. 725.
last provisos)
5:475j (1st sentence; and
2d sentence, less 2d and
last provisos)
5:628e (1st sentence; and
2d sentence, less 2d and
last provisos)
2353 (b) 5:235e (2d proviso of 2d
sentence)
5:475j (2d proviso of 2d
sentence)
5:628e (2d proviso of 2d
sentence)
2353 (c) 5:235e (last proviso of 2d
sentence)
5:475j (last proviso of 2d
sentence)
5:628e (last proviso of 2d
sentence)
In subsection (a), the words "furnished to" and "for the use
thereof" are omitted as surplusage.
In subsections (a) and (b), the words "United States" are sub-
stituted for the word "Government".
In subsection (b), the introductory clause is substituted for
5:235e (words of 2d proviso before clause (1)), 475j, and 628e.
The words "that. . . considers" are substituted for the words "as
will in the opinion". The words "an alternative" are substituted
for the words "such other".
In subsection (c), the words "Proceeds of" are substituted for
the words "That all moneys arising from".
-------
962 LEGAL COMPILATION—RADIATION
SECTION 2354
Revised
Section Source (U.S. Code) Source (Statutes at Large)
2354 (a) 5:235f (1st sentence, less July 16, 1952, eh. 882, §5, 66 Stat.
provisos) 726.
5:475k (1st sentence, less
provisos)
5:628f (1st sentence, less
provisos)
2354 (b) 5:235f (1st proviso of 1st
sentence)
5:475k (1st proviso of 1st
sentence)
5:628f (1st proviso of 1st
sentence)
2354 (c) 5:235f (last proviso of
1st sentence)
5:475k (last proviso of
1st sentence)
5:628f (last proviso of
1st sentence)
2354 (d) 5:235f (less 1st sentence)
5:475k (less 1st sentence)
5:628f (less 1st sentence)
In subsection (a), the words "Liability on account of", and "of
such claims" are omitted as surplusage. In clauses (1) and (2),
the word "from" is substituted for the words "arising as a result
of".
[p. 149]
1.4b(3) CONGRESSIONAL RECORD
1.4b(3)(a) VOL. 101 (1955), Aug. 1: Amended and passed House,
pp. 12718-12719
[No Relevant Discussion on Pertinent Section]
1.4b(3)(b) VOL. 102 (1956), July 23: Amended and passed Senate, p.
13953
[No Relevant Discussion on Pertinent Section]
1.4b(3)(c) VOL. 102 (1956), July 25: House concurs in Senate
amendments, p. 14455
[No Relevant Discussion on Pertinent Section]
-------
STATUTES AND LEGISLATIVE HISTORY 963
1.5 INTERNATIONAL HEALTH RESEARCH ACT, 22 U.S.C. §2101
(1960)
[Referred to in 42 U.S.C. §242f (a)]
22 § 2101. Statement of purpose
It is the purpose of this chapter and section 242f of Title 42—
(1) to advance the status of the health sciences in the
United States and thereby the health of the American people
through co-operative endeavors with other countries in health
research, and research training; and
(2) to advance the international status of the health
sciences through cooperative enterprises in health research,
research planning, and research training.
Pub.L. 86-610, § 2, July 12, 1960, 74 Stat. 364.
-------
964 LEGAL COMPILATION—RADIATION
1.5a FOREIGN ASSISTANCE ACT OF 1961, SEPTEMBER 4, 1961
P.L. 87-195, Ft. I, §241, 75 Stat. 433
TITLE V—DEVELOPMENT RESEARCH
SEC. 241. GENERAL AUTHORITY.—The President is authorized to
use funds made available for this part to carry out programs of
research into, and evaluation of, the process of economic develop-
ment in less developed friendly countries and areas, into the fac-
tors affecting1 the relative success and costs of development
activities, and into the means, techniques, and such other aspects of
development assistance as he may determine, in order to render
such assistance of increasing value and benefit.
[p. 433]
1.5a(l) SENATE COMMITTEE ON FOREIGN RELATIONS
S. REP. No. 612, 87th Cong., 1st Sess. (1961)
FOREIGN ASSISTANCE ACT OF 1961
JULY 24, 1961.—Ordered to be printed
Mr. FuLBRIGHT, from the Committee on Foreign Relations,
submitted the following
REPORT
[To accompany S. 1983]
The Committee on Foreign Relations, having had under consid-
eration the bill (S. 1983), the Foreign Assistance Act of 1961,
reports the bill favorably with amendments and recommends that,
as amended, it be passed by the Senate.
1. MAIN PURPOSE OF THE BILL
The main purpose of the bill is to give vigor, purpose, and new
direction to the foreign aid program. Thus, the stress of the pro-
gram is shifted to development loans repayable on manageable
terms and conditions but in dollars. Long-term financing becomes
available to the new aid agency, a simpler structure which will in-
clude the Development Loan Fund and the International Coopera-
-------
STATUTES AND LEGISLATIVE HISTORY 965
tion Administration. Less emphasis is placed on and fewer funds
are granted to direct support programs. Self-help and long-term
development planning are now the chief criteria against which the
bulk of economic aid is programed.
Funds for categories of economic and technical assistance other
than the contingency fund, are authorized to be made available
until expended. The same is true of military assistance. This
means that unused funds in these categories are carried over into
another fiscal year instead of automatically returning to the
Treasury. The bill, in short, stresses orderly economic growth
and gives continuity to the programs that will encourage and
sustain much of this growth.
[p. 1]
1.5a(2) HOUSE COMMITTEE ON FOREIGN AFFAIRS
H.R. REP. No. 851,87th Cong., 1st Sess. (1961)
MUTUAL SECURITY ACT OF 1961
AUGUST 4, 1961.—Committed to the Committee of the Whole House on the State
of the Union and ordered to be printed
Mr. MORGAN, from the Committee on Foreign Affairs, submitted
the following
REPORT
[To accompany H.R. 8400]
The Committee on Foreign Affairs, to whom was referred the
bill (H.R. 8400) to promote the foreign policy, security, and gen-
eral welfare of the .United States by assisting peoples of the world
in their efforts toward economic and social development and in-
ternal and external security, and for other purposes, having con-
sidered the same, report favorably thereon without amendment
and recommend that the bill do pass.
[p. 1]
-------
966 LEGAL COMPILATION—RADIATION
TITLE V—DEVELOPMENT RESEARCH
This title represents a new program designed to contribute the
results of systematic investigation to the improvement and the di-
rection of economic aid programs. The President is authorized to
use funds available for part I for the purposes of this title.
In his special message on foreign aid of March 22, 1961, the
President proposed—
a program of research, development, and scientific evaluation
to increase the effectiveness of our aid effort.
The program authorized by this title is largely the product of rec-
ommendations put forward by the President's Scientific Advisory
Committee. It is contemplated as a modest program, to be con-
ducted on an experimental basis and involving an expenditure of
not more than $20 million and possibly less. It represents an ef-
fort to minimize the difficulties inherent in economic and social
development. In the southern continents, where the major portion
of aid funds is programed, conditions are vastly different from
those in our own country. Climate, soils, diseases, traditions, and
social patterns all pose problems that can frustrate development
programs.
A good deal of research being undertaken in this country by the
foundations and universities is relevant to the problems in the less
developed societies. One of the major purposes of the development
research program is to relate this research more directly to spe-
cific problems. First, needs and requirements must be identified
and given priorities. In some countries, the primary need is the
development of people. Educational and training techniques
normally used in the West may be irrelevant to problems that arise
from mass illiteracy, absence of basic skills, and divergent cul-
tural and social patterns. Thus, technical assistance programs
will have the intended effect in a given country only if they are
designed to cope with the problems peculiar to that country. The
hope is that our research programs may discover more appropriate
educational and training techniques.
In some countries, the main problem is finding a way to harness
the resources of the country to its development plan. The tech-
nical problems may involve agriculture, mining, power, industry,
and public administration. The techniques and methods suitable
for tackling one country's combination of technical problems may
not be applicable to another's. Again, it is hoped that research
programs will find some answers for specialized situations.
It is contemplated that most of the activities under this program
will serve the purpose of improving the capability of less developed
-------
STATUTES AND LEGISLATIVE HISTORY 967
countries to analyze their own problems. The committee heard
testimony that—
In the end it is they who will have to deal with their own
technical, economic, and social problems. One of the most
[p. 18]
critical bottlenecks is the very limited number of people
in the underdeveloped countries capable of analyz-
ing their own problems systematically. Wherever pos-
sible research should be carried on jointly by people and
institutions with research experience in the United States
and Europe and by analysts in the underdeveloped coun-
tries themselves.
Another big need is a better understanding of the interrelation-
ships among economic, political and social changes.
The program should encourage the research community to un-
dertake more projects that are relevant to the problems of the
societies we are seeking to assist. And it should serve as a clear-
inghouse in which research activities can be evaluated and related
to these societies.
The committee, in approving this program, was mindful that
research and development occupies an important role in private
enterprise and in Government operations. More than 9 percent
of the Federal budget is spent on research and development. It
would seem highly advisable to expose the complicated and difficult
problems of the less developed areas to the formidable talents of
the American research community.
[p. 19]
TITLE V—DEVELOPMENT RESEARCH
Section 241. General authority
Title V authorizes the President to carry out programs of eval-
uation and research designed to contribute the results of system-
atic investigation into the improvement and effectiveness of the
development assistance program in economically underdeveloped
countries and areas. The President is authorized to use funds
available for part I to carry out the purposes of this title.
In his special message on foreign aid of March 22, 1961, the
President asked that there be initiated "a program of research,
development and scientific evaluation to increase the effectiveness
of our aid effort." The program authorized by this title is largely
the product of the recommendations in the report of the Develop-
-------
968 LEGAL COMPILATION—RADIATION
ment Assistance Panel of the President's Science Advisory Com-
mittee. (See hearings, p. 971.)
Research in many branches of the Government and private ac-
tivity throughout the United States and the industrialized world
has shown how enormously the capacity to deal with complex, new,
and unfamiliar problems can be accelerated and improved, and,
effectively
[p. 40]
applied, may result in reduction in costs. The committee is
convinced that there is a real and definite need for a research
program within the AID agency.
The research program will be called upon to fill the gap in the
development phase of research activities, that is, testing new tech-
niques in the environment in which they will actually be used. A
systematic evaluation of new ideas, as they are put into practice,
will therefore be a key function. In addition, the program will
direct its overall efforts to encouraging an innovative attitude
toward their own problems by the underdeveloped countries them-
selves, since in the long run it is they who will have to deal with
their own economic and social problems. Wherever possible, proj-
ects of joint research will be promoted in which research special-
ists and institutions in the United States will cooperate with
analysts in the underdeveloped countries. Finally, as stated by
Dr. Max Millikan of MIT and a member of the President's Sci-
ence Advisory Committee, before the Committee on Foreign
Affairs—
an AID agency-sponsored research program can perform an
enormously valuable function in stimulating a wider aware-
ness in the research community of the United States of the
problems of the underdeveloped countries and in generating,
over time, a much larger pool of talent in this country with the
training and interests required for participation in the de-
velopment program.
Examples of the kinds of research projects which might be un-
dertaken were cited in the testimony given the committee, such as
simple power systems; transportation network requirements in
underdeveloped countries and areas; educational systems to meet
the needs of predominantly illiterate societies at the local level,
and public health programs geared to the resources available.
Whatever the area of research is determined to be, the basic
knowledge available to the research unit will have to be imag-
inatively adapted to local conditions.
-------
STATUTES AND LEGISLATIVE HISTORY 969
It is contemplated that the research program will be directed
within the Office of Development Research and Assistance in the
AID agency by a small staff, numbering about 20, of the highest
quality from the scientific research community. Research proj-
ects will be undertaken mainly by contract with universities and
other research institutions and agencies, although the research
unit may be called upon to provide direct research assistance to
the regional bureaus during the course of planning, execution, or
evaluation of specific projects. As findings are tested and become
available for field application, this Office will suggest the best ways
of incorporating them into national development plans and pro-
grams. Finally, the Office will provide professional and tech-
nical leadership and overall guidance to the regional bureaus in
matters relating to the development and utilization of human re-
sources, that is, training of people to participate in the develop-
ment of their countries. In addition, the Office will maintain
liaison with the academic and scientific community, both private
and governmental.
The research program will not duplicate other research work
undertaken in the field of economic development assistance; rather,
it will at first rely heavily on material already available. The
committee believes that primary consideration should be given to
comprehensive
[p. 41]
analysis and evaluation of the processes of giving assistance,
as well as to actual projects involved. American religious
and other voluntary agencies have for decades been con-
ducting educational, medical, agricultural, social and cultural
programs in the cities, villages and countryside of all the under-
developed countries of the world. A vast amount of invaluable
experience has been gained by the most reliable method of all:
trial and error. It was unfortunate and caused unnecessary delay
in our governmental foreign assistance programs that too little
study was given earlier to these worldwide operations. The com-
mittee believes that perhaps the first major effort of the new Of-
fice of Development Research and Assistance should be to collect,
organize and evaluate the data already available. The findings
and considerations of such evaluation can give guidance to the
fields and methods which new research should most profitably
explore.
The specific technical assistance research programs already con-
tracted for under the International Cooperation Administration
will continue.
The Executive requested a separate authorization of $20 million
-------
970 LEGAL COMPILATION—RADIATION
to carry out the program. Since the research effort in the develop-
ment assistance program will begin on an experimental basis, and
a vast amount of material in the field of economic growth and de-
velopment will have to be reviewed and evaluated before the con-
tribution of the program to the development assistance program
gains impetus, the committee believes that the new research pro-
gram can meet its initial requirement from the funds provided in
part I.
Oceanography
The committee in the course of its consideration of title V dis-
cussed the possibility of an international cooperative effort in re-
search and development of the ocean's resources. The committee
recognizes the importance of such a program. Knowledge of the
oceans (oceanography), the resources which are contained therein,
and the manner in which the oceans are utilized and exploited by
various foreign nations all have a direct application to the eco-
nomic, military, and political postures of those nations. The
economic and military aspects are particularly important and the
oceanographic data or knowledge obtained for one aspect is di-
rectly useful for and applicable to the other. Testimony before the
committee mentioned fundamental research in oceanography as
one of the scientific areas which the development research pro-
gram can draw upon where applicable to the problems of econom-
ically underdeveloped countries. Where activities in the field of
oceanography complement assistance furnished under other parts
of this bill, it may be appropriate to finance them with mutual se-
curity funds.
[p. 42]
-------
STATUTES AND LEGISLATIVE HISTORY 971
1.5a(3) COMMITTEE OF CONFERENCE
H.R. BEP. No. 1088,87th Cong., 1st Sess. (1961)
FOREIGN ASSISTANCE ACT OF 1961
AUGUST 30, 1961.—Ordered to be printed
Mr. MORGAN, from the committee of conference, submitted the
following
CONFERENCE REPORT
[To accompany S. 1983]
The committee of conference on the disagreeing votes of the two
Houses on the amendment of the House to the bill (S. 1983) to
promote the foreign policy, security, and general welfare of the
United States by assisting peoples of the world in their efforts
toward economic development and internal and external security,
and for other purposes, having met, after full and free conference,
have agreed to recommend and do recommend to their respective
Houses as follows:
That the Senate recede from its disagreement to the amendment
of the House and agree to the same with an amendment as follows:
In lieu of the matter proposed to be inserted by the House
amendment insert the following:
* # $ $ $ # #
[p. 1]
TITLE V—DEVELOPMENT RESEARCH
SEC. 241. GENERAL AUTHORITY.—The President is authorized to
use funds made available for this part to carry out programs of
research
[p. 9]
into, and evaluation of, the process of economic development
in less developed friendly countries and areas, into the fac-
tors affecting the relative success and costs of development
activities, and into the means, techniques, and such other aspects
of development assistance as he may determine, in order to render
such assistance of increasing value and benefit.
[p. 10]
-------
972 LEGAL COMPILATION—RADIATION
1.5a(4) CONGRESSIONAL RECORD, VOL. 107 (1961)
1.5a(4)(a) Aug. 16: Passed Senate, p. 16411
[No Relevant Discussion on Pertinent Section]
1.5a(4) (b) Aug. 17: Amended and passed House, p. 16501
[No Relevant Discussion on Pertinent Section]
1.5a(4)(c) Aug. 31: Senate agrees to conference report, p. 17712
[No Relevant Discussion on Pertinent Section]
1.5a(4)(d) Aug. 31: House agrees to conference report, p. 17862
[No Relevant Discussion on Pertinent Section]
1.5b FOREIGN ASSISTANCE ACT OF 1963
December 16,1963, P.L. 88-205, Pt. I, §105, 77 Stat. 382
SEC. 105. Section 241 of the Foreign Assistance Act of 1961, as
amended, which relates to development research, is amended by
inserting " (a)" after the section heading and by adding at the end
thereof the following new subsection:
"(b) Funds made available to carry out this section may be
used to conduct research into the problems of population growth."
[p. 382]
-------
STATUTES AND LEGISLATIVE HISTORY 973
1.5b(l) HOUSE COMMITTEE ON FOREIGN AFFAIRS
H.R. KEP. No. 646, 88th Cong., 1st Sess. (1963)
FOREIGN ASSISTANCE ACT OF 1963
AUGUST 8, 1963.—Committed to the Committee of the Whole House on the State
of the Union and ordered to be printed
Mr. MORGAN, from the Committee on Foreign Affairs, submitted
the following
REPORT
[To accompany H.R. 7885]
The Committee on Foreign Affairs, to whom was referred the
bill (H.R. 7885) to amend further the Foreign Assistance Act of
1961, as amended, and for other purposes, having considered the
same, report favorably thereon without amendment and recom-
mend that the bill do pass.
[p. 1]
1.5b(2) SENATE COMMITTEE ON FOREIGN RELATIONS
S. REP. No. 588, 88th Cong., 1st Sess. (1963)
FOREIGN ASSISTANCE ACT OF 1963
OCTOBER 22, 1963.—Ordered to be printed
Mr. FuLBRlGHT, from the Committee on Foreign Relations,
submitted the following
REPORT
[To accompany H.R. 7885]
The Committee on Foreign Relations, to whom was referred the
bill H.R. 7885, to amend further the Foreign Assistance Act of
-------
8-24-7ki—2ml4
974 LEGAL COMPILATION—RADIATION
1961, as amended, and for other purposes, having considered the
same, reports the bill favorably with an amendment in the nature
of a substitute and recommends that the bill as amended do pass.
[p. 1]
TITLE V—DEVELOPMENT RESEARCH
Population growth (sec. 105)
Section 241 of the act, which authorizes the President to carry
out programs of research on processes and techniques of economic
development, is amended by the addition of a provision authorizing
the use of research funds to conduct studies of the problems of
controlling population growth and to provide assistance to co-
operating countries in carrying out programs of population
control.
Because of the profound impact of population growth on eco-
nomic development, the committee considers it appropriate to pro-
vide explicit authority for the conduct of research and technical
assistance activities in this field. It is the view of the committee
that population growth must be regarded as a critical factor in the
development prospects of countries which receive development as-
sistance from the United States.
No less than general education and technical, administrative,
and managerial competence, the capacity of a country to maintain
a reasonable balance between population and resources is a vital
factor in its prospects for successful economic development. It is
a well-known fact that in many less-developed countries rapid
population growth has substantially or entirely negated the ben-
efits of U.S. economic assistance. Even in some countries where
economic growth has been impressive, per capita income levels
have remained virtually stagnant as a result of mushrooming in-
creases in population.
Substantial progress has been made in recent years in defining
the preconditions of economic growth. To a great extent our
economic assistance has been refocused on those countries which
have largely fulfilled these preconditions. The one vital criterion
of successful development which has been neglected is that of
population control. The purpose of the committee's amendment to
title V of the act is to encourage research into appropriate meas-
ures to correct this omission.
[p. 14]
TITLE V—DEVELOPMENT RESEARCH
SEC. 241. GENERAL AUTHORITY.— (a) The President is author-
ized to use funds made available for this part to carry out pro-
grams of research into, and evaluation of, the process of economic
-------
STATUTES AND LEGISLATIVE HISTORY 975
development in less developed friendly countries and areas, into
the factors affecting- the relative success and costs of development
activities, and into the means, techniques, and such other aspects
of development assistance as he may determine, in order to render
such assistance of increasing value and benefit.
(b) Funds made available to carry out this section may be used
to conduct research into the problems of controlling population
groivth and to provide technical and other assistance to cooperat-
ing countries in carrying out programs of population control.
[p. 52]
1.5b(3) COMMITTEE OF CONFERENCE
H.R. REP. No. 1006, 88th Cong., 1st Sess. (1963)
FOREIGN ASSISTANCE ACT OF 1963
DECEMBER 6, 1963.—Ordered to be printed
Mr. MORGAN, from the committee of conference, submitted the
following
CONFERENCE REPORT
[To accompany H.R. 7885]
The committee of conference on the disagreeing votes of the two
Houses on the amendment of the Senate to the bill (H.R. 7885) to
amend further the Foreign Assistance Act of 1961, as amended,
and for other purposes, having met, after full and free conference,
have agreed to recommend and do recommend to their respective
Houses as follows:
That the House recede from its disagreement to the amendment
of the Senate and agree to the same with an amendment as
follows:
In lieu of the matter proposed to be inserted by the Senate
amendment insert the following: That this Act may be cited as
the "Foreign Assistance Act of 1963".
[p. 1]
-------
976
LEGAL COMPILATION—RADIATION
TITLE V—DEVELOPMENT RESEARCH
SEC. 105. Section 24-1 of the Foreign Assistance Act of 1961, as
amended, which relates to development research, is amended by
inserting "(a)" after the section heading and by adding at the end
thereof the following new subsection:
"(b) Funds made available to carry out this section may be used
to conduct research into the problems of population groivth."
[p. 5]
POPULATION PROBLEMS (SEC. 105)
The Senate amendment included a provision that "funds made
available to carry out this section may be used to conduct research
into the problems of controlling population growth and to provide
technical and other assistance to cooperating countries in carrying
out programs of population control."
The House bill did not contain a comparable provision.
The managers on the part of the House agreed to a modification
of the Senate provision so that it provides that "funds made avail-
able to carry out this section may be used to conduct research into
the problems of population growth."
The managers on the part of the House accepted the language
as modified in the belief that in view of the population problems in
the less developed countries, research on such problems appears to
be warranted.
[p. 21]
1.5b(4) CONGRESSIONAL RECORD, VOL. 109 (1963)
1.5b(4)(a) Aug. 23: Passed House, p. 15678
[No Relevant Discussion on Pertinent Section]
1.5b(4)(b) Oct. 24, Nov. 15: Debated, amended and passed Senate,
p. 21978
MEMORANDUM TO SENATOR HUMPHREY FROM
PAT HOLT
# * -:- * *
3. A new subsection (b) was added to section
241, relating to development research, which
reads as follows:
"Funds made available to carry out this sec-
tion may be used to conduct research into the
problems of controlling population growth and
to provide technical and other assistance to
cooperating countries in carrying out programs
of population control."
The committee report (p. 14) states:
"Because of the profound impact of popula-
tion growth on economic development, the com-
mittee considers it appropriate to provide
explicit authority for the conduct of research
and technical assistance activities in this field.
It is the view of the committee that population
growth must be regarded as a critical factor in
the development prospects of countries which
-------
STATUTES AND LEGISLATIVE HISTORY
977
receive development assistance from the United
States."
"No less than general education and technical,
administrative, and managerial competence, the
capacity of a country to maintain a reasonable
balance between population and resources is a
vital factor in its prospects for successful eco-
nomic development. It is a well-known fact
that in many less-developed countries rapid
population growth has substantially or entirely
negated the benefits of U.S. economic assistance.
Even in some countries where economic growth
has been impressive, per capita income levels
have remained virtually stagnant as a result of
mushrooming increases in population.
"Substantial progress has been made in recent
years in denning the preconditions of economic
growth. To a great extent our economic assist-
ance has been refocused on those countries which
have largely fulfilled these preconditions. The
one vital criterion of successful development
which has been neglected is that of population
control. The purpose of the committee's amend-
ment to title V of the act is to encourage re-
search into appropriate measures to correct this
omission."
[p. 21978]
1.5b(4)(c) Dec. 9: Conference report submitted in House and agreed
to, p. 23850
[No Relevant Discussion on Pertinent Section]
1.5b(4)(d) Dec. 13: Conference report agreed to in Senate, pp. 24453-
24454
FOREIGN ASSISTANCE ACT OF 1963—
CONFERENCE REPORT
The Senate resumed the considera-
tion of the report of the committee of
conference on the disagreeing votes of
the two Houses on the amendment
of the Senate to the bill (H.R. 7885) to
amend further the Foreign Assistance
Act of 1961, as amended, and for other
purposes.
Mr. MORSE. Mr. President, at this
time I suggest that there be a quorum
call, with the understanding that the
time required for it not be charged to
the time available to either side.
The ACTING PRESIDENT pro
tempore. Is there objection? Without
objection, it is so ordered; and the
clerk will call the roll.
The Chief Clerk proceeded to call the
roll.
Mr. MORSE. Mr. President, I ask
unanimous consent that the order for
the quorum call may be rescinded.
The ACTING PRESIDENT pro
tempore. Without objection, it is so
ordered.
Mr. MORSE. Mr. President, I yield
5 minutes to the Senator from Pennsyl-
vania [Mr. CLARK] from the time
available on the conference report.
Mr. CLARK. Mr. President, I
should like to express my keen disap-
pointment in the action of the con-
ferees in striking from the conference
report one-half of section 105 of the
Senate bill, which dealt with the prob-
lem of controlling population growth.
Senators will recall the Senate pro-
vision stated on page 21 of the report
of the managers on the part of the
House:
Funds made available to carry out this section
may be used to conduct research into the prob-
lems of controlling population growth and to
provide technical and other assistance to coop-
erating countries in carrying out programs of
population control.
The report of the managers on the
part of the House states that the man-
agers agreed to a modification of the
[p. 24453]
Senate provision so that it would in-
clude the first part of the Senate
amendment. The conferees, however,
struck out the second part of the Sen-
ate amendment, which would have au-
thorized the provision of technical and
-------
978
sszb—epa—B-JJ.-/;;—1"15
LEGAL COMPILATION—RADIATION
other assistance to cooperating coun-
tries in carrying out programs of pop-
ulation control.
The second part of section 105—that
is, the part which the conferees struck
out at the insistence of the House—was
a valuable provision and should have
been retained.
Senators will recall that this year,
for the first time, the Senate took
formal cognizance of the existence of
the population problem, not only in
the United States, but all over the
world. I have had occasion frequently
to advert to the problem, and so has the
Senator from Alaska [Mr. GRUENING] .
The chairman of the Senate Foreign
Relations Committee, the Senator from
Arkansas [Mr. FULBRIGHT] took the in-
itiative in inserting section 105 into
the Senate version of the Foreign As-
sistance Act of 1963. So far as I know,
there was no objection either in the
Foreign Relations Committee or on the
floor of the Senate to section 105, as
the Senator from Arkansas [Mr. FUL-
BRIGHT] had steered the bill through
committee and through floor action.
The Senator from Alaska [Mr.
GRUENING] and I had occasion to point
out that the attitude of the Catholic
Church toward measures of population
control has drastically altered.
Dr. John Rock has published, with
substantial support from the Catholic
Church, of which he is a devout mem-
ber, a book entitled "The Time Has
Come." The burden of the book is that
the time has come to speak out on the
critical problem of population control.
A number of other eminent Catholics,
including Monsignor O'Brien of Notre
Dame University, have spoken out on
the same subject.
There is now developing a consensus
among all religious bodies and thought-
ful citizens of the need for the Govern-
ment to take a good, hard look at prob-
lems of population control, particularly
in underdeveloped countries.
I regret, therefore, that the House
conferees were unwilling to accept the
provision which passed the Senate
without objection. I am glad, however,
that the conference report recommends
the expenditure of funds to conduct re-
search into the problem of controlling
population growth. I would hope that
the Administrator of the program
would construe this provision very
broadly indeed.
The ACTING PRESIDENT pro
tempore. The time of the Senator
from Pennsylvania has expired.
Mr. CLARK. Mr. President, will the
Senator yield me 1 additional minute?
Mr. MORSE. I yield the Senator 1
more minute.
The ACTING PRESIDENT pro
tempore. The Senator from Pennsyl-
vania is recognized for 1 additional
minute.
Mr. CLARK. Mr. President, I reit-
erate my hope that the Administrator
of the program will construe the au-
thorization retained in the conference
report very broadly and that in the
next fiscal year we shall see a real
breakthrough in efforts to establish,
through programs of research, a mean-
ingful series of methods for investi-
gating through statistical data, and
for creating through planning pro-
grams population control which can be-
gin to make an impact on the quite
frightening problem of population
growth which confronts the whole
world.
I point out that two of every three
human beings will go to bed hungry
tonight and that an unlimited birth
rate is perhaps the single most serious
obstacle to bringing to those two of
every three people an adequate diet
and an opportunity for a healthy and
useful life.
I thank my friend for yielding.
Mr. MORSE. Mr. President, I
yield 3 minutes to the Senator from
Ohio [Mr. YOUNG].
The ACTING PRESIDENT pro
tempore. The Senator from Ohio [Mr.
YOUNG] is recognized for 3 minutes.
[p. 24454]
-------
STATUTES AND LEGISLATIVE HISTORY 979
1.6 PER DIEM, TRAVEL AND TRANSPORTATION EXPENSES;
EXPERTS AND CONSULTANTS; INDIVIDUALS SERVING
WITHOUT PAY, AS AMENDED
5 U.S.C. §5703 (1966)
[Referred to in 42 U.S.C. §242f(b)(5),(6)]
(See, "General 1.15a-1.15d(3)(c)" for legislative history)
5 § 5703.
(a) For the purpose of this section, "appropriation" includes
funds made available by statute under section 849 of title 31.
(b) An individual employed intermittently in the Government
service as an expert or consultant and paid on a daily when-
actually-employed basis may be allowed travel expenses under
this subchapter while away from his home or regular place of
business, including a per diem allowance under this subchapter
while at his place of employment.
(c) An individual serving without pay or at $1 a year may be
allowed transportation expenses under this subchapter and a per
diem allowance under this section while en route and at his place
of service or employment away from his home or regular place
of business. Unless a higher rate is named in an appropriation
or other statute, the per diem allowance may not exceed—
(1) the rate of $25 for travel inside the continental United
States; and
(2) the rates established under section 5702 (a) of this
title for travel outside the continental United States.
(d) Under regulations prescribed under section 5707 of this
title, the head of the agency concerned may prescribe conditions
under which an individual to whom this section applies may be
reimbursed for the actual and necessary expenses of the trip, not
to exceed an amount named in the travel authorization, when the
maximum per diem allowance would be much less than these
expenses due to the unusual circumstances of the travel assign-
ment. The amount named in the travel authorization may not
exceed—
(1) $40 for each day in a travel status inside the con-
tinental United States; or
(2) the maximum per diem allowance plus $18 for each
day in a travel status outside the continental United States.
Pub.L. 89-554, Sept. 6, 1966, 80 Stat. 499; amended Pub.L.
91-114, § 2, Nov. 10, 1969, 83 Stat. 190.
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980 LEGAL COMPILATION—RADIATION
1.7 THE SOLID WASTE DISPOSAL ACT, AS AMENDED
42 U.S.C. §3254f (1970)
42 § 3254f. National disposal sites study for the storage and dis-
posal of hazardous wastes
The Secretary shall submit to the Congress no later than two
years after October 26, 1970, a comprehensive report and plan
for the creation of a system of national disposal sites for the
storage and disposal of hazardous wastes, including radioactive,
toxic chemical, biological, and other wastes which may endanger
public health or welfare. Such report shall include: (1) a list of
materials which should be subject to disposal in any such site;
(2) current methods of disposal of such materials; (3) recom-
mended methods of reduction, neutralization, recovery, or dis-
posal of such materials; (4) an inventory of possible sites includ-
ing existing land or water disposal sites operated or licensed by
Federal agencies; (5) an estimate of the cost of developing and
maintaining sites including consideration of means for distrib-
uting the short- and long-term costs of operating such sites
among the users thereof; and (6) such other information as may
be appropriate.
Pub.L. 89-272, Title II, § 212, as added Pub.L. 91-512, Title I,
§ 104 (b), Oct. 26, 1970, 84 Stat. 1233.
-------
STATUTES AND LEGISLATIVE HISTORY 981
1.7a THE RESOURCE RECOVERY ACT OF 1970
October 26,1970, P.L. 91-512, Title I, §104(b), 84 Stat. 1233
SEC. 104.
(b) The Solid Waste Disposal Act is amended by redesignating
sections 207 through 210 as sections 213 through 216, respectively,
and by inserting after section 206 (as so redesignated by subsec-
tion (a) of this section) the following new sections:
"NATIONAL DISPOSAL SITES STUDY
"SEC. 212. The Secretary shall submit to the Congress no later
than two years after the date of enactment of the Resource Re-
covery Act of 1970, a comprehensive report and plan for the crea-
tion of a system of national disposal sites for the storage and
disposal of hazardous wastes, including radioactive, toxic chem-
ical, biological, and other wastes which may endanger public health
or welfare. Such report shall include: (1) a list of materials
which should be subject to disposal in any such site; (2) current
methods of disposal of such materials; (3) recommended methods
of reduction, neutralization, recovery, or disposal of such mate-
rials; (4) an inventory of possible sites including existing land or
water disposal sites operated or licensed by Federal agencies; (5)
an estimate of the cost of developing and maintaining sites includ-
ing consideration of means for distributing the short- and long-
term costs of operating such sites among the users thereof; and
(6) such other information as may be appropriate."
[p. 1233]
-------
982 LEGAL COMPILATION—KADIATION
1.7a(l) HOUSE COMMITTEE ON INTERSTATE AND
FOREIGN COMMERCE
H.R. REP. No. 91-1155, 91st Cong., 2d Sess. (1970)
RESOURCE RECOVERY ACT OF 1970
JUNE 4, 1970.—Committed to the Committee of the Whole House on the State
of the Union and ordered to be printed
Mr. STAGGERS, from the Committee on Interstate and Foreign
Commerce, submitted the following
REPORT
[To accompany H.R. 11833]
The Committee on Interstate and Foreign Commerce, to whom
was referred the bill (H.R. 11833) to amend the Solid Waste Dis-
posal Act in order to provide financial assistance for the construc-
tion of solid waste disposal facilities, to improve research
programs pursuant to such act, and for other purposes, having
considered the same, report favorably thereon with an amendment
and recommend that the bill as amended do pass.
The amendment strikes out all of the bill after the enacting
clause and inserts in lieu thereof a substitute which appears in the
reported bill in italic type.
[P. 1]
-------
STATUTES AND LEGISLATIVE HISTORY 983
1.7a(2) SENATE COMMITTEE ON PUBLIC WORKS
S. REP. No. 91-1034, 91st Cong., 2d Sess. (1970)
RESOURCE RECOVERY ACT OF 1970
JULY 23, 1970.—Ordered to be printed
Mr. MUSKIE, from the Committee on Public Works, submitted the
following
REPORT
together with an
INDIVIDUAL VIEW
[To accompany S. 2005]
The Committee on Public Works, to which was referred the bill
(S. 2005) to amend the Solid Waste Disposal Act, as amended, re-
lating to financial assistance for the construction of solid waste dis-
posal facilities, improving research programs pursuant to such
Act, establishing a National Commission on Materials Policy, and
for other purposes, having considered the same, reports favorably
thereon with amendments and recommends that the bill as
amended do pass.
[p. 1]
NATIONAL DISPOSAL SITES STUDY
Considerable recent attention has been focused on disposal of
materials which present a high risk to public health and welfare
because of their toxicity or mutagenic effects. Congressional at-
tention to such hazardous materials was reflected in the Water
Quality Improvement Act of 1970, which requires identification of
hazardous materials and a study of liability for the cost of cleaning
up such materials when discharged into the navigable waters of
the United States.
Hazardous materials are often present in solid wastes. When
released into the environment, they often cause ecological damage
and risks to public health.
Frequently such materials are dumped into the ocean. The en-
vironmental implications of this practice are not understood. A
-------
984 LEGAL COMPILATION—RADIATION
prudent public policy necessitates discouraging or prohibiting this
practice. Alternative methods must be developed and provided for
disposal of these wastes.
The objective must be to dispose of these hazardous materials so
that their deleterious impact is eliminated. One approach is to
provide a system of national disposal sites which would be sup-
ported by user fees.
It is the opinion of the committee that further information is
needed on the desirability and feasibility of a system of solid waste
disposal sites for hazardous materials.
The bill directs the Secretary to prepare a report and plan for
the creation of a system of national disposal sites for the storage
and disposal of hazardous wastes. The report is to include a list
of materials which may endanger public health and welfare as well
as current and recommended methods for disposal of these mate-
rials. This section directs that the study include disposal meth-
ods for radioactive materials, toxic chemical wastes, biological
materials, and other hazardous materials.,
This study would provide an inventory of disposal sites cur-
rently operated or licensed by Federal agencies including both land
and water disposal sites.
The report required by this legislation should include a compila-
tion of current practices for the disposal of hazardous materials on
land and at sea, including recommendations on practices that
should be discontinued.
In proposing possible sites for inclusion in a system of national
disposal sites, the Secretary is expected to estimate the costs of
developing and maintaining such a system. These estimates
should include proposals for distributing the costs for operating
such sites between public and private users of such sites, and con-
tract arrangements for employing any expertise of the private
sector to operate such sites.
[p. 16]
-------
STATUTES AND LEGISLATIVE HISTORY 985
1.7a(3) COMMITTEE OF CONFERENCE
H.R. REP. No. 91-1579, 91st Cong., 2d Sess. (1970)
RESOURCE RECOVERY ACT OF 1970
OCTOBER 7, 1970.—Ordered to be printed
Mr. STAGGERS, from the committee of conference, submitted the
following
CONFERENCE REPORT
[To accompany H.R. 11833]
The committee of conference on the disagreeing votes of the two
Houses on the amendment of the Senate to the bill (H.R. 11833) to
amend the Solid Waste Disposal Act in order to provide financial
assistance for the construction of solid waste disposal facilities, to
improve research programs pursuant to such Act, and for other
purposes, having met, after full and free conference, have agreed
to recommend and do recommend to their respective Houses as
follows:
That the House recede from its disagreement to the amendment
of the Senate and agree to the same with an amendment as
follows:
In lieu of the matter proposed to be inserted by the Senate
amendment insert the following:
[P. i]
"NATIONAL DISPOSAL SITES STUDY
"SEC. 212. The Secretary shall submit to the Congress no later
than two years after the date of enactment of the Resource Re-
covery Act of 1970, a comprehensive report and plan for the crea-
tion of a system of national disposal sites for the storage and dis-
posal of hazardous wastes, including radioactive, toxic chemical,
biological, and other wastes ivhich
[p. 7]
may endanger public health or welfare. Such report shall include:
(1) a list of materials which should be subject to disposal in any
such site; (2) current methods of disposal of such materials;
(3) recommended methods of reduction, neutralization, recovery,
-------
986 LEGAL COMPILATION—EADIATION
or disposal of such materials; (4) an inventory of possible sites
including existing land or water disposal sites operated or licensed
by Federal agencies; (5) an estimate of the cost of developing and
maintaining sites including consideration of means for distributing
the short- and long-term costs of operating such sites among the
users thereof; and (6) such other information as may be ap-
propriate."
[p. 8]
New section 212 of act (national disposal sites study)
The Senate amendment inserted a new section 212 in the act,
which provided for a 2-year national disposal sites study. The
Secretary was directed to make a comprehensive report and plan
for the creation of a system of national disposal sites for the stor-
age and disposal of hazardous wastes, including radioactive, toxic
chemical, biological, and other wastes which may endanger public
health or welfare. The report would include (1) a list of mate-
rials subject to disposal; (2) current methods of disposal of such
materials; (3) recommended methods of disposal of such mate-
rials; (4) an inventory of possible sites; and (5) cost estimates.
The House bill had no comparable provision. The House recedes
on this provision.
[p. 16]
1.7a(4) CONGRESSIONAL RECORD, VOL. 116 (1970)
1.7a(4) (a) June 23: Passed House, p. 20893
[No Relevant Discussion on Pertinent Section]
1.7a(4)(b) Aug. 3: Considered, amended and passed Senate, p. 26942
[No Relevant Discussion on Pertinent Section]
1.7a(4)(c) Oct. 7: Senate agreed to conference report, pp. 35511,
35516
[No Relevant Discussion on Pertinent Section]
1.7a(4)(d) Oct. 13: House agreed to conference report, p. 36587
[No Relevant Discussion on Pertinent Section]
-------
STATUTES AND LEGISLATIVE HISTORY 987
1.8 NATIONAL ENVIRONMENTAL POLICY ACT OF 1969
42 U.S.C. §§4332(2)(c), 4344(5) (1970)
(See, "General 1.2a-1.2a(4)(e)" for legislative history)
§4332. Cooperation of agencies; reports; availability of information;
recommendations; international and national coordination of
efforts
The Congress authorizes and directs that, to the fullest extent
possible:
*******
(2) all agencies of the Federal Government shall—
*******
(C) include in every recommendation or report on proposals
for legislation and other major Federal actions significantly affect-
ing the quality of the human environment, a detailed statement by
the responsible official on—
(i) the environmental impact of the proposed action,
(ii) any adverse environmental effects which cannot be
avoided should the proposal be implemented,
(iii) alternatives to the proposed action,
(iv) the relationship between local short-term uses of
man's environment and the maintenance and enhancement of
long-term productivity, and
(v) any irreversible and irretrievable commitments of re-
sources which would be involved in the proposed action should
it be implemented.
Prior to making any detailed statement, the responsible Federal
official shall consult with and obtain the comments of any Federal
agency which has jurisdiction by law or special expertise with
respect to any environmental impact involved. Copies of such
statement and the comments and views of the appropriate Federal,
State, and local agencies, which are authorized to develop and en-
force environmental standards, shall be made available to the Pres-
ident, the Council on Environmental Quality and to the public as
provided by section 552 of Title 5, and shall accompany the pro-
posal through the existing agency review processes;
-------
988 LEGAL COMPILATION—RADIATION
§4344. Duties and functions
It shall be the duty and function of the Council—
*******
(5) to conduct investigations, studies, surveys, research,
and analyses relating to ecological systems and environmental
quality;
-------
Executive
Orders
-------
-------
STATUTES AND LEGISLATIVE HISTORY 991
2.1 E.G. 10831, ESTABLISHMENT OF THE FEDERAL
RADIATION COUNCIL
August 14,1959, 24 Fed. Reg. 6669 (1959)
By virtue of the authority vested in me as President of the
United States, it is hereby ordered as follows:
Section 1. (a) There is hereby established the Federal Radia-
tion Council (hereinafter referred to as the "Council").
(b) The Council shall be composed of the Secretary of Defense,
the Secretary of Commerce, the Secretary of Health, Education,
and Welfare, and the Chairman of the Atomic Energy Commis-
sion.
(c) The Chairman of the Council shall be designated by the
President, from time to time, from among the members of the
Council.
Section 2. The Council shall advise the President with respect
to radiation matters directly or indirectly affecting health, includ-
ing matters pertinent to the general guidance of executive agen-
cies by the President with respect to the development by such
agencies of criteria for the protection of humans against ionizing
radiation applicable to the affairs of the respective agencies. The
Council shall take steps designed to further the interagency coor-
dination of measures for protecting humans against ionizing
radiation.
Section 3. The Special Assistant to the President for Science
and Technology, or his representative, is authorized to attend
meetings of, to participate in the deliberations of, and to advise
with, the Council.
Section 4. For the purpose of effectuating this order, each
executive agency represented on the Council shall furnish neces-
sary assistance to the Council, in consonance with section 214 of
the act of May 3, 1945, 59 Stat. 134 (31 U.S.C. 691). Such assis-
tance may include detailing employees to the Council to perform
such duties consistent with the purposes of this order as the
Chairman of the Council may assign to them. Upon the request
of the Chairman of the Council, the heads of executive agencies
shall so far as practicable provide the Council information and
reports relating to matters within the cognizance of the Council.
Section 5. The Council may seek technical advice, in respect
of its functions, from any source it deems appropriate.
DWIGHT D. EISENHOWER
-------
-------
Regulations
-------
-------
REGULATIONS 995
EPA's Office of Radiation Programs has not promulgated any reg-
ulations. Guidelines for Uranium Miner Exposure are found under
the "Guidelines and Reports" section. Reorganization Plan No. 3 of
1970 transferred to EPA certain powers previously held by the
Atomic Energy Commission. EPA is currently establishing a
viable "interface" with the AEC. AEC regulations which EPA
is reviewing, are those that deal with releases of radiation to the
environment and are currently found under Title 10 of the Code
of Federal Regulations. Chapters of particular interest are ch. 20
("Standards for Protection Against Radiation"), and ch. 30
("Rules of General Applicability to Licensing of Byproduct
Material").
-------
-------
Guidelines
and
Reports
-------
-------
GUIDELINES AND REPORTS 999
4.1 BACKGROUND MATERIAL FOR THE DEVELOPMENT
OF RADIATION PROTECTION STANDARDS, STAFF
REPORT OF THE FEDERAL RADIATION COUNCIL
4.1a BACKGROUND MATERIAL FOR THE DEVELOPMENT
OF RADIATION PROTECTION STANDARDS, REPORT
NO. 1, STAFF REPORT OF THE FEDERAL RADIATION
COUNCIL, MAY 13, 1960
CONTENTS
Page
I.—Introduction 1
II.—Knowledge of Radiation Effects 4
III.—Sources of Radiation Exposure 19
IV.—The Derivation of Radiation Protection Standards 23
V.—Basic Guides 26
VI.—Derived Guides 31
VII.—Summary and Recommendations 36
[p. iii]
SECTION 1.—INTRODUCTION
1.1 It was recognized soon after discovery of x-rays that ex-
posure to large amounts of ionizing radiation can produce de-
leterious effects on the human body so exposed. More recently,
because of increased scientific knowledge and widespread use of
radiation, additional attention has been directed to the possible
effects of lower levels of radiation on future generations. Various
scientific bodies have made recommendations to limit the irradia-
tion of the human body. Probably the oldest of such scientific
bodies are the International Commission on Radiological Protec-
tion (ICRP) and the U. S. National Committee on Radiation Pro-
tection and Measurements (NCRP). Initially, these bodies were
interested primarily in the irradiation of those exposed occupa-
tionally, but recently they have been concerned with those who are
non-occupationally exposed.
1.2 The ICRP was formed in 1928 under the auspices of the In-
ternational Congress of Radiology. It is now a Commission of the
International Society of Radiology. This Commission has pub-
lished recommendations about every three years except for the
period 1938-49.
1.3 The NCRP was initially organized as the "Advisory Com-
-------
1000 LEGAL COMPILATION—RADIATION
mittee on X-ray and Radium Protection." The initial member-
ship included representatives from the medical societies, x-ray
equipment manufacturers, and the National Bureau of Standards.
After the reorganization in 1946, the name was changed to the
National Committee on Radiation Protection and Measurements,
and additional representatives from other organizations having
scientific interest in the field were included. The recommenda-
tions of this group have generally been published as National
Bureau of Standards handbooks. Since 1947, 15 such handbooks
have been made available on different aspects of the protection
problem.
1.4 In 1956, the National Academy of Sciences-National Re-
search Council published reports of its Committees on the Biolog-
ical Effects of Atomic Radiation. For genetic protection this
group recommended a maximum gonadal dose up to age 30 both
for individual radiation workers and for the entire population.
These committees published a revised report in 1960.
1.5 The recommendations of the NCRP, ICRP, and NAS-NRC
are in rather close agreement. The recommendations of the NCRP
have received wide acceptance in the United States.
1.6 In 1955, The United Nations established a Scientific Com-
mittee on The Effects of Atomic Radiation (UNSCEAR). The
report of this group (UNSCEAR, 1958) summarized the current
knowledge on effects of radiation exposure and on human exposure
levels. The report also contained predictions on exposures from
testing of nuclear devices under various assumptions.
1.7 The Joint Committee on Atomic Energy of the Congress
held public hearings in 1957 on "The Nature of Radioactive Fall-
out and Its Effects on Man." The same committee held hearings
in 1959 on "Industrial Radioactive Waste Disposal;" on "Employee
Radiation Hazards and Workman's Compensation;" on "Fallout
from Nuclear Weapons Tests;" and on "Biological and Environ-
mental Effects of Nuclear War." In all these hearings, questions
of the biological effects of radiation and of protection against ex-
cessive exposure to radiation received attention.
1.8 The Federal Radiation Council was formed in 1959 (Public
Law 86-373) to provide a Federal policy on human radiation ex-
posure. A major function of the Council is to ". . . advise the Pres-
ident with respect to radiation matters, directly or indirectly
affecting health, including guidance for all Federal agencies in the
formulation of radiation standards and in the establishment and
execution of programs of cooperation with States. . . ." This staff
report is a first step in carrying out this responsibility. As knowl-
edge of the biological effects of radiation increases, and as factors
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GUIDELINES AND REPORTS 1001
making exposure to radiation desirable undergo change, modifica-
tions and amplifications of the recommendations of this staff report
probably will be required.
[p. 1]
SCOPE
1.9 This staff report seeks to provide some of the required ra-
diation protection recommendations. These recommendations are
of an interim nature. Periodic review will be necessary to in-
corporate new information as it develops. This staff report in-
cludes recommendations for additional research which will provide
a firmer basis for the formulation of radiation standards.
1.10 Only peacetime uses of radiation which might affect the
exposure of the civilian population are considered at this time.
The staff report also does not consider the effects on the population
arising from major nuclear accidents. Only that portion of the
knowledge of the biological effects of radiation that is significant
for setting radiation protection standards is considered. Pub-
lished information by the groups indicated above is summarized
in this staff report; details may be found in the original reports.
1.11 Certain of the classes of radiation sources are now reg-
ulated by various Federal agencies. There are some which are
not so regulated but which should be considered as aspects of the
overall exposure of the population to radiation. Therefore, this
staff report will consider exposure of the population from all
sources except those excluded above.
PREPARATION OF THE STAFF REPORT
1.12 In preparation of this staff report, a series of meetings^as
arranged with staff members of various Federal agencies con-
cerned with radiation protection. The objectives of this first
phase in the preparation were (1) to determine the problems
unique to these agencies, (2) to define problem areas not ade-
quately covered by current radiation protection recommendations
of the National Committee on Radiation Protection and Measure-
ments or the National Academy of Sciences; and (3) to discuss the
implications of the above recommendations.
1.13 A second phase in the preparation of this staff report con-
sisted of a series of consultations with Governmental and non-
governmental scientists in the various fields involved in the
development of radiation protection standards. The purposes of
these consultations were (1) to discuss the bases upon which rec-
ommendations on radiation protection standards are formulated;
(2) to obtain the most up-to-date information on the biological ef-
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1002 LEGAL COMPILATION—RADIATION
fects of radiation and (3) to elucidate some of the physical and
chemical problems involved in the establishment and implementa-
tion of radiation protection standards.
1.14 These consultations and the reports of the groups indicated
above provided a basis for the present staff report.
DEFINITIONS 1
1.15 The activity of a radioactive source is the number of nu-
clear disintegrations of the source per unit of time. The unit of
activity is the curie. The weight of a radionuclide corresponding
to one curie is directly proportional to the half-life and to the
atomic weight of the nuclide. For example, uranium-235 with a
half life of 7.07 x 10s years requires about 4.65 x 105 grams to ob-
tain an activity of one curie. The mass-activity relationship for
iodine-131 with a half life of 8.0 days is about 8.05 x Kh8 grams
to produce a curie.
1.16 Any biological effect produced by radiation depends on an
absorption of energy from the radiation. For many years the
roentgen (r)1 has been used as a measure of x- and gamma ray
absorption in body tissue. Conceptually, the roentgen is only a
measure of the ability of x- or gamma-rays to produce ionization
in air and not of the absorption of these rays in tissue. More re-
cently (ICRU H62, 1957), the absorbed dose of any radiation has
been denned as "the energy imparted to matter by ionizing par-
ticles per unit mass of irradiated material at the place of interest."
The unit of absorbed dose is the rad. However, under most con-
ditions and to the accuracy required for radiation protection pur-
poses, the number of roentgena is numerically equal to the number
of rads in soft tissues.2
[p. 2]
1.17 The same absorbed dose of different kinds of radiation does
not, in general, produce the same biological effect. Different kinds
of radiation have a different relative biological effectiveness
(RBE). It is well known that the RBE for a particular kind of
radiation may be dependent upon such factors as the specific bi-
ological effect under consideration, the tissue irradiated, the radia-
tion dose, and the rate at which it is delivered. Recommendations
on radiation protection have generally assumed a specific RBE for
each kind of radiation.3 The RBE dose is equal numerically to the
iFor detailed definitions see ICRU, H62, 1957.
-For the accuracy of this approximation and the conditions for its applicability, see the In-
ternational Commission Radiological Units (ICRU) Report (1957).
"Currently used values of RBE (relative to x-rays) are one for x-rays, gamma rays and elec-
trons, 10 for neutrons, and piotons up to 10 Mev, and alpha particles, and 20 fol heavy lecoil
nuclei. These are for chronic irradiation and should be used only for protection purposes.
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GUIDELINES AND REPORTS 1003
product of the dose in rads and an agreed conventional value of the
relative biological effectiveness. The unit of RBE dose is the rem,
considered to be that dose which is biologically equivalent to one
roentgen of x- or gamma-radiation. For example, one rad of
neutrons is conventionally considered to be equivalent to 10 roent-
gens of gamma radiation, and this equivalence is expressed by
saying that the RBE dose is 10 rem. However, it has been found
experimentally that the same RBE dose of different radiation
sources in the bone does not always produce the same biological
effect. A numerical factor called the relative damage factor is
introduced to take care of this difference. Thus, in the case of
bone, the biological effect is represented by the product of the RBE
dose and the relative damage factor.
1.18 Radiation Protection Guide (RPG) is the radiation dose
which should not be exceeded without careful consideration of the
reasons for doing so; every effort should be made to encourage the
maintenance of radiation doses as far as below this guide as
practicable.
1.19 Radioactivity Concentration Guide (RCG) is the concen-
tration of radioactivity in the environment which is determined to
result in whole body or organ doses equal to the Radiation Pro-
tection Guide.
CONTENTS OF THE STAFF REPORT
1.20 The following sections of this staff report provide informa-
tion on human exposure from radiation sources, the present state
of our knowledge on the genetic and somatic effects of radiation,
the problems of formulating radiation protection standards from
available scientific data, the basic and derived radiation protection
guides, recommendations for further work by the Federal Radia-
tion Council, and indications as to areas, in which research is
needed in order to fill gaps in our basic knowledge.
[p. 3]
SECTION II.—KNOWLEDGE OF RADIATION EFFECTS
INTRODUCTION
2.1 This section includes general summaries of knowledge of the
biological effects of ionizing radiation on animals and man par-
ticularly pertinent to the problem of defining radiation protection
standards. As noted in Section I (paragraph 1.13), this staff re-
port was developed following a series of consultations with sci-
entists who provided recent information on the genetic and somatic
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1004 LEGAL COMPILATION—RADIATION
effects of radiation. The consultations included the experimental
evidence in animals and the observations on humans, as well as the
assumptions, hypotheses, and unknowns in the relationships of
radiation dose and effects.
DEFINITIONS OF GENERAL BIOLOGICAL FACTORS
2.2 Radiation exposure can be described in terms of the part of
the body exposed, the total dose delivered, the dose rate, and the
duration of the exposure. Acute exposure is usually considered
an exposure to a single event of irradiation or a series of events in
a short period of time. Continuous or fractionated exposures over
a long period of time are considered chronic exposures.
2.3 Acute exposure can result in both immediate and delayed
biological effects. Chronic exposure is usually considered to pro-
duce only delayed effects. The acute radiation syndrome will not
be discussed in detail since it is applicable primarily to accidental
or emergency exposures. The literature documents this effect
(refer to Table 2.1).
2.4 The available data describing immediate effects on humans
include:
(1) Medical data on effects following the therapeutic use of external sources
such as X-rays, and of radionuclides such as radium, iodine, etc.;
(2) Occupational data on exposure of radiologists, cyclotron workers, and
workers in nuclear industry as a result of certain accidents; and
(3) Population observations on atomic bomb survivors and on persons irradi-
ated by heavy fallout in the vicinity of the Marshall Islands.
2.5 Most delayed effects, in man, are inferred from considera-
tion of experimental knowledge in animals, from available epidem-
iological statistical observations, and from a limited number of
medical and industrial case observations. Delayed effects are
those effects observable at some time following exposure. The
effects considered are: (1) genetic effects; and (2) somatic effects,
including the appearance of leukemia, skin changes, precancerous
lesions, neoplasms, cataracts, changes in the life span, and effects
on growth and development. The delayed effects produced by
ionizing radiation in an individual are not unique to radiation and
are for the most part indistinguishable from those pathological
conditions normally present in the population and which may be
induced by other causes.
2.6 External radiation exposure refers to that exposure result-
ing from sources outside the body. Classifications of external
radiation exposure are made on the basis of the portions of the
body irradiated: whole body or partial body.
2.7 Internal radiation exposure is that which comes from radio-
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GUIDELINES AND REPORTS
1005
active materials incorporated within the body following their in-
gestion, inhalation, injection, or absorption.
2.8 A critical organ is defined as that organ of the body whose
damage by a given radiation source results in the greatest im-
pairment to the body. Criteria appropriate to the determination
of critical organs for external or internal exposure are: (1) the
radiosensitivity of the organ, i.e., the organ damaged by the lowest
[p. 4]
TABLE 2.1.—SUMMARY OF EFFECTS RESULTING FROM ACUTE WHOLE BODY
EXTERNAL EXPOSURE OF RADIATION TO MAN '
0-25 r
No
detectable
clinical
effects.
Delayed
effects
may occur.
25-100 r
Slight
transient
reductions
in lympho-
cytes and
neutrophils.
Disabling
sickness not
common, ex-
posed indi-
viduals
should be
able to pro-
ceed with
usual duties.
Delayed ef-
fects possi-
ble, but
serious ef-
fects on
average indi-
vidual very
improbable.
100-200 r
Nausea and
fatigue,
with pos-
sible vom-
iting above
125 r.
Reduction in
lymphocytes
and neutro-
phils with
delayed re-
covery.
Delayed ef-
fects may
shorten life
expectancy
in the order
of one per
cent.
200-300 r
Nausea and
vomiting on
first day.
Latent period
up to two
weeks or per-
haps longer
Following
latent period
symptoms ap-
pear but are
not severe:
loss of appe-
tite, and gen-
eral malaise,
sore throat,
pallor,
petecheae,
diarrhea,
moderate
emaciation.
Recovery
likely in about
3 months un-
less compli-
cated by poor
previous
health, super-
imposed in-
juries or in-
fections.
300-600 r
Nausea, vomiting
and diarrhea in
first few hours.
Latent period with
no definite symp-
toms, perhaps as
long as one week.
Epilation, loss of
appetite, general
malaise, and fever
during second
week, followed by
hemorrhage, pur-
pura, petecheae,
inflammation of
mouth and throat,
diarrhea, and
emaciation in the
third week.
Some deaths in 2
to 6 weeks. Pos-
sible eventual
death to 50% of
the exposed in-
dividuals for
about 450
roentgens.
600 or more
Nausea, vom-
iting and di-
arrhea in first
few hours.
Short latent
period with no
definite symp-
toms in some
cases during
first week.
Diarrhea,
hemorrhage,
purpura, in-
flammation of
mouth and
throat, fever
toward end of
first week.
Rapid emacia-
tion and death
as early as the
second week
with possible
eventual death
of up to 100%
of exposed in-
dividuals.
1 Adapted from "The Effects of Nuclear Weapons," U S. Government Printing Office, 1957.
dose; (2) the essentialness or indispensability of the organ to the
well-being of the entire body; (3) the organ that accumulates the
greatest concentration of the radioactive material; and (4) the
organ damaged by the radionuclide enroute into, through, or out of
the body. For a given situation, determination of the criteria
chosen for internal emitters is subject to judgment based on var-
-------
1006 LEGAL COMPILATION—RADIATION
ious factors; physical (particle size), chemical (solubility; the com-
pound form of a given chemical element), ecological (the
environmental balance of calcium or iodine) and physiological
(differential uptake by age and the metabolic condition of the
organism).
2.9 On the basis of comparisons with known effects of x-rays in
humans and animals, radioisotope experiments in animals, and the
radium and other radioisotope observations in man, certain organs
in the body appear to be the critical organs under various condi-
tions of irradiation. These organs, and examples of the delayed
effect of irradiation upon these organs are: (1) gonads: genetic
alterations; (2) bone marrow and other blood forming organs: the
leukemias, aplastic anemia; (3) whole body: life span shortening;
(4) single organs (bone, skin, thyroid, etc): neoplasms, and other
[p. 5]
pathological effects; and, (5) the lens of the eye: cataracts. These
are the effects ordinarily considered when assigning guides for ex-
ternal and internal exposure.
2.10 A body burden of a radionuclide is that amount present in
the body. The organ burden is the amount present in an organ.
2.11 Multiple exposures may occur from diverse sources, e.g.,
from several sites of deposition and from several routes of entry
into the body. Sources may be external or internal. An external
source may irradiate the whole body or a portion of the body. An
internal source or sources may produce radiation exposure in sev-
eral ways: (1) a single radionuclide may produce whole body ex-
posure or a single organ exposure; or (2) single nuclides may
affect different body organs simultaneously; or lastly, (3) multiple
radionuclides may be absorbed thereby producing whole body, or
single, or several organ exposures.
BIOLOGICAL VARIABILITY
2.12 Variations of effect with age depend upon metabolic, cel-
lular, and organ differences. Some factors of significance are:
(1) Radiation sensitivity of a cell in terms of chromosomal aberration de-
pends on the stage of mitosis when radiation is delivered. Damage becomes
manifest when cell division takes place; the more divisions that occur, the
greater probability of manifestation.
(2) During fetal life there is a greater sensitivity to radiation and the
median lethal dose (LDso) of fetuses is less than that of adults. After birth,
in certain strains of mice the radiosensitivity decreases until maturity is
reached, and then remains relatively constant until late in life when radiosensi-
tivity again rises sharply.
(3) Gross malformations may result from small amounts of radiation deliv-
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GUIDELINES AND REPORTS 1007
ered to the developing embryo. The production of clinically evident malforma-
tions in fetal life depends on the stage of embryonic organ development when
the radiation is delivered.
2.13 Although few data are available on human populations it
is presumed from the analogy of other stresses that undernourish-
ment and strain may affect radiosensitivity. Anemia renders mice
more sensitive to radiation. However, from the evidence on radio-
biological studies of tissue culture, and on the induction of muta-
tions and biochemical effects, it has been shown that a reduction in
oxygen tension produces a lowered response to radiation.
2.14 There is a scarcity of information on the effect produced
by the simultaneous presence of bone-seeking nuclides (radium,
strontium) and bone infection or bone conditions in which the min-
eral states are altered due to aging.
2.15 The minimum doses causing biological effects detectable by
current methods differ among species. However, for most mam-
mals the LD50 dose varies by less than an order of magnitude.1
Comparison of genetic effects between the fruit fly and the mouse
can be cited. The x-ray induced mutation rate per r per average
gene locus varies by a factor of 15 between fruit fly and mouse.
For mouse spermatogonia the sensitivity of the mutation rate per
locus (at 90 r per min.) from least to most sensitive locus may
vary by a factor of 30; while in the fruit fly the specific locus sen-
sitivity varies by a factor of two. Our ability to extrapolate con-
fidently the data from animal experience to man depends on
whether there is sufficient evidence of similarity between humans
and the experimental animals.
2.16 Within an individual, the range of tissue sensitivity varies
by more than an order of magnitude from the more sensitive
(blood forming organs) to the more resistant (the adult nervous
system).
2.17 The apparent sensitivity of a tissue to damage depends on
the index of measurement used, e.g., the biochemical effect, the
mitotic effect, the cellular effect, or states of tissue derangement,
tumor production, or life span changes. As examples, (1) for
changes in the lens of the eye, one may measure the clinical ap-
pearance of cataracts years after radiation injury, or one may
measure the immediate biochemical changes; (2) lymphocyte
damage may be measured by the reduction in the number of lym-
phocytes, or by the structural changes in the cell nucleus, or by the
chemical change in nuclear DNA content; and (3) the effect on
bone marrow may be measured by the appearance of immature
[p. 6]
1 The term, an order of magnitude, as used in this staff report refers to a factor of ten.
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1008 LEGAL COMPILATION—RADIATION
cells in the blood stream or by the rate and amount of Fe-59 in-
corporated in the cells.
2.18 In an individual adult it is difficult or in some cases impos-
sible to detect effects from a single external exposure of less than
25 to 50 r, and from continuing exposure to levels even about two
orders of magnitude greater than natural background. It should
be noted, however, that changes in the nucleus of lymphocytes have
been described in some adult radiation workers after two weeks of
exposure to levels as low as 0.20 r per week.
2.19 Man's sensitivity to radiation depends on his age at the
time of exposure. Considering his long life, the time periods of
importance are: for genetic considerations, the interval from con-
ception to the end of the reproductive period; and for somatic ef-
fects, the total lifetime during which delayed effects may become
manifest.
(1) Embryonic neuroblasts in vitro are sensitive to a dose of radiation of
orders of magnitude smaller than the dose which kills adult nerve cells.
(2) In fetal organ systems, effects (e.g., delayed effects on blood forming
tissues) may be evident with 2-10 r acute expos-ure, and skeletal effects with 24 r.
(3) The child's thyroid is more sensitive than the adult thyroid. Cancer of
the thyroid has been observed in children after an acute external exposure of
approximately 150 r. In adults the same effect has been observed only after
exposures of more than several hundred r.
(4) A study of the differential sensitivity for induction of skin tumors by
x-ray (used in the treatment of hemangiomas) showed that children were 3-4
times more sensitive than adults.
(5) In adults, the presence of disease states may be correlated with the later
appearance of neoplasms, apart from the effects of radiation. This has been
reported in ankylosing spondylitics who later developed leukemia.
2.20 In addition to differential sensitivity there are important
factors of differential uptake between adults and children. Some
of these are:
(1) The rate of deposition of skeletal calcium and the fractions of equilibrium
Sr-90/Ca ratio for accretion and for remodeling of bone are each a complex
function of age; each may vary by a factor of at least 10 from newborn to age
twenty.
(2) The uptake of iodine per gram of tissue by the normally functioning
thyroid gland differs widely between children and adults.
(3) Different age groups are exposed to different environmental radiation
conditions. For example, because of differences in dietary intake an infant may
be exposed to different total amounts of Sr-90 radiation than an adult.
2.21 There is a current definition for the "average" adult—
"Standard Man." The "Standard Man" is denned in such terms
as organ size, distribution of elements in the body organs, fluid
intake and excretion, and air balance. Each of these factors differs
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GUIDELINES AND REPORTS 1009
between adults and children, and also differs among various age
groups of children. Therefore, there is a need for a comparable
definition of "Standard Children" to be used in developing Radio-
activity Concentration Guides.
DOSE-EFFECT RELATIONS FOR GENETIC AND SOMATIC EFFECTS
2.22 Among the possible dose-effect relationships at least three
possibilities have been considered in the literature: (1) a linear,
no threshold concept; (2) a nonlinear, no threshold concept; and
(3) a nonlinear, threshold concept. Among the parameters which
must be considered in the relationships are the total dose, the dose
rate, the biochemical or clinical manifestation of effect, and the
period of time in which the effect becomes manifest.
2.23 The evidence for linearity and no threshold for induction
of mutations in the genetic material is based on work with fruit
flies and mice. The method consists in the scoring of the occur-
[p. 7]
rence of specific traits in progeny of irradiated animals. In study-
ing irradiated males, the experimenter can determine the genetic
manifestations in the progeny corresponding to the stages of de-
velopment of spermatogonia and spermatozoa in the parent. This
can be accomplished by selecting suitable time intervals between
irradiation and mating. Experimentally it measures visible traits
in the offspring (such as coat color changes in the mouse or fail-
ing of pupal development in the fruit fly). These traits are then
attributed to specific gene mutations in the parent germ cell. The
effect is therefore considered to be directly proportional to the
number of genetic changes induced in the parental germ cell. It is
well demonstrated that the curve showing effect against dose in ex-
perimental animals is linear within the range of 37 r to 1,000 r
total acute dose, and geneticists believe that there is no threshold
for the genetic effect. The finding of a dose-rate dependence ef-
fect (chronic exposure is approximately one-fourth as effective in
inducing mutations as is acute exposure) probably represents par-
tial recovery at low dose-rates and does not conflict with the no
threshold concept.
2.24 For somatic effects, unlike genetic mutation effects, there
is no general agreement among scientists on the dose-effect rela-
tionships. It is known, for example, that the nature of the dose-
response curve can be altered drastically by changes in the external
environment of the organism. In addition, although radiation may
be the initiating event, there may be other promoting factors op-
erating before the manifestations are evident. Such factors men-
-------
1010 LEGAL COMPILATION—RADIATION
tioned in the literature include cocarcinogens: hormones, chem-
icals, and viruses.
2.25 Because of the complexities of animals and man, there may
be many mechanisms by which radiation produces effects. One of
the mechanisms may be the induction of a primary effect by radia-
tion which, after a sequence of secondary events over a period of
time, leads to a clinical manifestation such as neoplasia. In this
hypothesis, the induction of the primary effect could be consistent
with a linear no threshold concept of dose-effect relationship, yet
the successive manifestations of the damage could be nonlinear
and not consistent with a threshold concept. Therefore, in the case
of neoplasia, the demonstration of linearity or nonlinearity for the
gross effect does not predict the presence or absence of a threshold
dose for the primary insult.
2.26 There are some somatic effects in animals which do not
support a linear no threshold concept (e.g., acute mortality;
splenic, thymic and testicular atrophy, incidence of lens opacity,
duration of depression of mitotic activity, and incidence of het-
erologous tumor implants). However, the experiments demon-
strating these effects were not performed primarily to examine
threshold theory and were done at high dose ranges above 100 r.
Considering the diversity of results in different species of animals,
extrapolations to man for these effects at low doses should be made
with caution.
2.27 In man, the chief evidence for a linear dose-effect relation-
ship for somatic effects comes from some of the leukemia studies
(see Table 2.2). Data are available for acute exposures above 50
rads in adults. Predictions of the incidence of leukemia in the gen-
eral population per rad of exposure have been made by extrap-
olations from these data. Certain of these predictions have
involved the assumption that the occurrence of radiation-induced
leukemia per rad will remain constant for the life of the popula-
tion, the assumption of no difference among effects of irradiation
of various parts of the body and the assumption of a constant prob-
ability of occurrence of leukemia per rad of acute and chronic ex-
posure. There is no direct evidence that justifies extrapolation
from the condition of acute exposure to one of a low dose chronic
external exposure, or to the radiation from internal emitters.
2.28 In summary, the evidence is insufficient to prove either the
hypothesis of a damage threshold or the hypothesis of no threshold
in man at low doses. Depending on the assumptions used, forceful
arguments can be made either way. It is therefore prudent to
adopt the working principle that radiation exposure be kept to the
lowest practical amount.
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GUIDELINES AND REPORTS 1011
GENETIC EFFECTS
2.29 The following working assumptions have been derived
from the evidence considered in this staff report: (1) radiation
induced mutations, at any given dose rate, increase in direct linear
[p. 8]
proportion to the genetically significant dose; - (2) mutations, once
completed, are irreparable; (3) almost all the observed effects of
mutations are harmful; (4) radiation-induced mutations are, in
general, similar to naturally occurring mutations; and, (5) there is
no known threshold dose below which some effect may not occur.
2.30 The linearity is established in fruit, flies down to 25 r and is
confirmed in mouse spermatogonia down to 37 r, but there is no
direct evidence for linearity below these doses. Although the
studies in animals do not involve a period comparable to the 80-
year period of chronic irradiation in humans, the hypothesis used
in this staff report is that the mutations induced by small dose
rates of radiation to human reproductive cells are cumulative over
long periods of time. Under this assumption, irradiation of the
whole population from any source is expected to have genetic
consequences.
2.31 In addition to genetic effects in the progeny of an exposed
individual, attention must be given to the total genetic effect on
the population. Within the working assumptions above, the total
genetic load is independent of the distribution of the exposure
within the population. Therefore, when radiation protection
standards are established for large numbers of exposed persons,
limitations may be imposed by considerations of population ge-
netics (the effects on population as a whole).
2.32 Major areas of uncertainty in genetic information for man,
with regard to both population and individual genetics, are the
estimations of: the spontaneous and induced mutation rates; the
genetic load of mutations; the influence of man-made factors (mor-
tality reduction brought about by health protection, for example)
operative in natural selection; and the influence of synergism of
gene interaction.
2.33 Formulation of radiation protection standards has been
based in part on estimates of genetic hazards to man. These in
turn have been based chiefly on data from mice and from acute
2 The genetically significant dose to the individual is considered to be the accumulated dose to
the gonads weighted by a factor for the future number of children to be conceived by the irra-
diated individual. The genetically significant dose for the population is defined as the dose which,
if received by every member of the population, would be expected to produce the same total
genetic injury to the population as do the actual gonad doses received by the various individuals.
-------
1012 LEGAL COMPILATION—RADIATION
rather than chronic irradiation. Results of recent experiments
considered pertinent to the evaluation of genetic effects are:
(1) The genetic effects under some radiation conditions may not be as great
as those estimated from the mutation rates obtained with acute irradiation. It
has been shown in mice that fewer specific locus mutations are produced in
spermatogonia and oocytes by a low dose rate (chronic gamma radiation at 90 r
per week) than by a high dose rate (acute irradiation at 90 r per minute) for
the same total accumulated dose above 100 r. A similar effect has been reported
for sex-linked lethal mutations in the oogonia of fruit flies. The number of
mutations induced in spermatogonia by chronic irradiation is smaller (about
one fourth) than that induced by acute irradiation.
(2) Studies being planned may define quantitatively the dose-effect relation-
ship with fractionated, low doses delivered at high dose rates. These data may
be of direct significance to medical practice using fluoroscopy and radiography.
(3) Life shortening has been demonstrated in the offspring of male mice ir-
radiated at high doses.
(4) Radiation doses of 25 r appear to produce chromosomal breakage in hu-
man cells grown in tissue culture.
Items (1) and (2) above indicate that in the preparation of
radiation protection standards based on the genetic effects, con-
sideration should be given to dose rate as well as total dose.
[p. 9]
LEUKEMIA
2.34 Information useful for study of the risk of leukemia among
exposed persons is based on experimental data on animals, some
observations on humans, and the rise in crude leukemia mortality
rates observed in many countries. There is more information
available on the correlation between radiation exposure and leu-
kemia incidence in man than there is for other radiation effects.
2.35 Most of the reported investigations indicate that the in-
cidence of leukemia among irradiated persons increases with the
exposure dose. A definitely increased incidence of leukemia occurs
after one large whole body dose or a large accumulated dose. The
available evidence applicable to the general population under the
assumptions listed in paragraph 2.27 indicates a linear correlation
of dose to incidence down to about 50 rads of whole body acute ex-
posure. The specific findings in other studies vary with the type
of exposure and are speculative at lower doses. There have been
reports that, during prenatal life, fetal doses as low as 2-10 r may
double the incidence of leukemia, although other studies have not
confirmed this finding. Prenatal exposure may be quite different
from exposure of adults and there is no evidence that these low
dose levels may be effective later in life. There is also no satis-
factory evidence that chronic lymphatic leukemia is produced by
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GUIDELINES AND REPORTS 1013
radiation although this is the form of leukemia primarily respon-
sible for the rising crude leukemia rate in the general population.
2.36 Past studies of leukemia-radiation correlations in human
populations have limitations imposed by retrospective epidemiolog-
ical techniques as well as factors inherent in the nature of leu-
kemia. Epidemiological techniques which are retrospective in
type are limited by the:
(1) difficulty of determination of the radiation dose;
(2) absence of uniform radiation recording methods;
(3) difficulty of associating medical and vital statistical records: i.e., such
studies introduce biases inherent in the techniques of interview, questionnaire,
or manual searching;
(4) statistical selection of cases which may be weighted with those cases
having a disease related in some way to leukemia; and
(5) the fact that the numbers of persons in the population groups studied
are usually small.
2.37 The following factors produce difficulties in the evaluation
of the findings on possible radiation produced leukemia:
(1) Although leukemia has the advantage of the use of simpler procedures
for the diagnosis of the disease than are available for other neoplastic diseases,
it has the disadvantage that the classification of various types of leukemia is
subject to debate. It is thus difficult to compare statistics of different origins.
(2) The hematological effects such as are seen in leukemia can also be ob-
served in other diseases which may or may not be radiation induced.
(3) Leukemia ascribed to radiation cannot be distinguished from leukemia
due to other causes.
(4) Leukemia in humans is a rare disease whose crude annual incidence in
the population-at-large is about 5 per 100,000 persons.
(5) The various forms of leukemia have different clinical courses and the
relative incidence of cytologic types varies with age. Not all the various forms
of leukemia can be placed in one category since it does not appear that the
chronic lymphatic form may be induced by radiation.
2.38 Considerations of the above factors require that epidemiol-
ogical studies include large samples of exposed subjects, provide
mechanisms for followr-up over long periods of time, provide ade-
quate control groups, and provide ascertainable exposure and
outcome.
[P. io]
2.39 Conclusions drawn from the studies listed in Table 2.2,
indicate that:
(1) Under certain conditions, there is a clear association between leukemia
and prior radiation exposure. This association has been demonstrated only
where the exposures are high. The effect may be discerned at doses of the
order of several thousand r for prolonged intermittent exposure over many
years in normal adults; or, doses of the order of 500 r for bone marrow ex-
posure in adult males with pre-existing disease; or, doses of the order of 50-100 r
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1014 LEGAL COMPILATION—RADIATION
for acute whole body exposure in a general population of all ages; or at acute
dose possibly as low as 2-10 r to the fetus;
(2) Long follow-up periods are required to assess cancer experience follow-
ing irradiation.
(3) Little data exist on leukemia incidence among women exposed to thera-
peutic doses of radiation from radium or x-rays;
(4) It is unlikely that retrospective studies will definitely solve the question
of the shape of the dose-response curve at low levels of exposure or the existence
of a threshold. Additional retrospective studies on population groups receiving
high doses of radiation may provide refined quantitative knowledge. There are
only a few prospective studies reported that can provide information on both
the quantitative and qualitative effects of chronic low doses received over many
years;
(5) The risk of any one individual developing leukemia is small even with
relatively large doses. However, when large populations are exposed, the abso-
lute number of people affected may be considerable.
2.40 The leukemogenic effect of internally deposited isotopes
requires special mention.
Strontium.—We have no documented evidence that bone deposi-
tions of strontium in humans have produced leukemia. State-
ments that radiostrontium is leukemogenic are based solely upon
studies in mice. Since leukemia is a common disease spontaneously
occurring in certain strains of mice, one cannot accept this ob-
servation as necessarily applicable to man.
Thorium.—Only a few cases of leukemia following thorium in-
jections for medical diagnosis have been reported in the literature.
The leukemias have occurred with latent periods up to 20 years.
However, the dose calculations for irradiation of the bone are
complicated by the presence of thorium daughters.
Radium.—No cases of leukemia have been reported in those
persons who have had radium deposited in their bones, even
though some persons developed bone cancers. This is not un-
expected in view of the fact that radium deposited in bones results
in a relatively small dose to the bone marrow.
Iodine.—Only a few cases of leukemia have been reported in
patients receiving iodine-131 for the medical treatment of hyper-
thyroidism and cancer of the thyroid. It would seem that well
planned large population studies on persons who received radio-
iodine medically would contribute to the knowledge of the leu-
kemogenic and carcinogenic effect at the levels used.
2.41 The possibility of the detection of low doses of radiation
by hematological techniques is deserving of high priority. The
most sensitive indicator available at present may be the counting
of binucleated lymphocytes, but the technique is not now practical
for wide applications because of the need to examine large num-
bers of cells on hematology slides. The development of practical
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GUIDELINES AND REPORTS 1015
electronic devices to screen these cytologic blood specimens should
be encouraged. The prognostic significance of the observations of
morphological changes in the lymphocytes will be elucidated by
long term follow-up of selected study and control groups.
OTHER NEOPLASMS AND PREMALIGNANT CHANGES
2.42 Clinical evidence indicates that irradiation in a sufficient
amount to most parts of the body may produce cancer as a delayed
effect although no inference of an incidence-dose relationship
should be drawn. Some of the evidence in humans is based on:
(1) skin cancers among radiologists in the early history of the use of x-ray;
(2) thyroid cancers in children irradiated in the neck region;
[p. 11]
(3) Leukemia among children who were exposed in utero to x-ray for pelvi-
metry of the mother;
(4) Bone sarcomas in radium dial painters and other persons exposed to
radium-226;
(5) Liver sarcomas in medical patients given thorotrast; and
(6) Bronchogenic cancer in miners occupationally exposed to radon and its
daughters.
2.43 The bulk of the evidence lies in the work done on animals
with external whole and partial body doses, as well as with intern-
ally absorbed radionuclides. Both benign and malignant lesions
have been produced, although the evidence is incomplete and there
is no simple relationship between carcinogenesis and dose. Mice
are more sensitive to all modalities of radiation exposure than man
for the induction of skin and ovarian tumors and leukemia.
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1016 LEGAL COMPILATION—RADIATION
' TABLE 2.2.—TYPES OF STUDIES THAT HAVE BEEN DONE IN HUMANS ON LEUKEMIA
AND RADIATION
I. Occupational 1. Cases not reported in the literature.
2. Scattered reports in the literature.
3. Radiologists.
4. Uranium miners.
II. Therapeutic and Diagnostic ... 1. Children receiving partial body exposure to x-rays:
a. Infants treated for thymus gland enlargement.
b. Infants similarly treated who had normal size thymus glands.
c. Children treated for pertussis and lymphoid hyperplasia.
d. Children treated for other benign conditions of many differ-
ent types.
e. Children treated for neuroblastoma.
2. Adults:
a. Patients with ankylosing spondylitis given x-ray treatment
to the spine.
b. Radiologists receiving partial body x-ray radiation over many
years.
c. Patients treated for hyperthyroidism with x-ray; and radio-
iodine
d. Patients treated for polycythemia and radiophosphorus.
3. Prenatal-
Maternal prenatal exposure to diagnostic doses of x-rays.
III. General Population Japanese people who received whole body irradiation from A-bomb
explosion.
IV. Internal Emitters 1. Thorotrast.
2. Radium.
3. Iodine.
4. Phosphorus.
[p. 12]
2.44 It is pertinent to the discussion of a threshold dose or dose
rate dependence for carcinogenesis to describe two theories of
radiation carcinogenesis: the direct somatic mutation effect and
the theory of indirect effect.
2.45 The direct theory postulates that the incidence of tumors
induced by radiation in a population is proportional to the dose.
This theory states, by direct analogy with genetic theory, that the
somatic cell may incur chromosomal changes which become evident
on cell division and lead to a neoplastic change. So far it is im-
possible to test this on human populations. Animal experiments
show that the effect is much more complicated. The theory of
indirect effect considers that there are tissue and hormonal factors
which mediate the occurrence and site of development of tumors
following irradiation.
2.46 The evidence bearing on the two theories may be sum-
marized as:
(1) The long latent period for development of tumors may indicate that they
develop only after a series of premalignant changes or states of tissue altera-
tion have taken place. As yet unknown is the sequence of events and how the
events are correlated with dose or dose rate. For example, the deposition of
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GUIDELINES AND REPORTS 1017
radium in bone may produce slight changes in the bone at lower levels, necrosis
at increasing levels, and bone tumors at high levels.
(2) In man, the latent period for cancer induction by radiation is often from
10 to 20 years, although for leukemia the period may be from 5 to 10 years after
a single whole body irradiation. For chronic exposure at low dose rates, it
would appear that the latent period is longer.
(3) Tissue changes induced by radiation need not occur at the site of injury.
There are indications that the critical factors may include responses of the
whole body to the radiation, rather than the radiation effect upon a single cell
exclusively; examples of this principle are:
(a) The primary cause of tumors such as mouse lymphomas or mouse
ovarian and pituitary tumors may be disturbances of an endocrine gland.
(b) Mouse experiments show that shielding of a part of the body will
prevent the appearance of radiation leukemia, or that shielding one ovary
will prevent a tumor from developing in the other.
(c) Cells grown in tissue culture (where growth inhibitory factors which
may be present in the body are lacking) have a tendency for malignant
variance entirely apart from considerations of radiation. Under certain
conditions, attempts to transplant a tumor to an animal are unsuccessful
until the animal has developed an autogenous metastatic malignancy.
(d) The presence, in an animal or man, of a cancer is associated with
an increased probability of occurrence of a second cancer, in a similar or
other tissue.
2.47 At chronic low levels of radiation the combination of vary-
ing susceptibility with age and the long latent period for tumor
induction complicates an analysis of dose-effect relationships. Ex-
perimental animals must be maintained for long periods of time
and there must be large numbers of animals to achieve statistically
significant results.
2.48 In man, the data seem to show that one must be exposed
to relatively high external exposure levels to show a carcinogenic
effect in certain tissues. For example, available information in-
dicates that cancers have been observed in persons receiving doses
in the range of 500 to 2,500 r to the skin. The thyroid carcinogenic
dose has been shown to vary greatly with age and may be one of
the most sensitive indices in children of the carcinogenic property
of radiation.
BONE TUMORS FROM INTERNAL EMITTERS
2.49 The two sets of crucial data on the problem are the human
radium experience and the animal experiments, now underway, on
comparative toxicity of radium, strontium, plutonium, and
thorium.
[p. 13]
2.50 Historically, the evidence leading to the first establishment
of a radium body burden limit, for occupational workers only, was
based on physical data and a small amount of biomedical informa-
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1018 LEGAL COMPILATION—KADIATION
tion on a few dozen adults. Summaries of new data on several
hundred living persons have been reviewed for this report. Per-
sons studied were workers who absorbed pure radium (or radium
plus mesothorium and radiothorium) in the course of radium dial
painting, or were patients treated medically with radium waters,
or were persons drinking public water supplies relatively high in
radium. The information permits the comparison of effect on
bone with body burden estimates of radium-226-equivalent present
after periods as much as 35 years of prolonged exposure. Present
physical techniques of estimation of body burden are based on
radon breath analysis, whole body gamma counting, excreta anal-
ysis, and the essay of teeth and bone. The complications of
dosimetry in some of the dial painters arising from the presence of
both radium and mesothorium are partially resolved, but the exact
equivalence of radium to mesothorium is not well established.
2.51 The clinical evaluation of the living persons studied in-
cludes a history, physical examination, and radiographic and
pathological studies. The criteria of effect are based on the dif-
ferential diagnosis of x-ray evidence of bone changes, the presence
of pathological fractures, bone tumors, changes in teeth or signs
of other fiindings.3 The period between exposure and observation
of skeletal changes by x-ray examination is usually determined by
the date of examination rather than the date of onset of skeletal
changes. Rarely are serial radiographs available over a period
during which the changes first appear. In other than special
microradiographic studies, there is no evidence available of cellular
or biochemical effects.
2.52 A major problem in evaluation of the hazard of radium
exposure is the definition of a clinically significant effect. If
clinically significant effect is defined in terms of significant injury
to the person, it may include only the symptomatic factors which
impair the person's daily living, energy or longevity (tumors and
pathological fractures). If clinically significant effect is defined
in terms of detectable changes, the index may be radiographic
evidence discernable to a competent physician. In either case the
changes indicate varying degrees of late effects and are observed
after many years of exposure.
2.53 It can be hypothesized that, on a cellular level, the effect
is linearly proportional to body burden. Gross demonstrable
changes plotted against dose could follow a normal distribution
even though the effect at the cellular level were linear.
; The indices used are: absence or presence of x-ray evidence of localized areas of bone rarefac-
tion, areas of increased density, abnormal tiabecular pattern, severe aseptic neciosis, pathological
fractuie; abnormal tooth structure; sarcoma; carcinoma at other sites; leukemia; anemia.
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GUIDELINES AND REPORTS 1019
2.54 In attempting to define effects which can be extrapolated to
the general population the following unknowns are apparent:
(1) the sequence of events during the latent period, as a function of dose;
(2) the radiobiological effect on small volumes of tissue;
(3) the site of injury and the degree of recovery from injury;
(4) the elapsed period of time from cellular injury to the evidence of the
effect and the possible interrelationships among bone osteitis, necrosis, patho-
logical fracture, and bone tumors;
(5) the variance in biological sensitivity with age; also, the variance in bone
physiology at all ages in humans, the structure of the organic matrix, the
crystalline and vascular structure, and the differences in homogeneity of distri-
bution of the bone seeking nuclides;
(6) the variations of body burden with time in the individual after a single
or fractionated intake; more radium retention data are needed in humans to
permit determination of body burdens at times less than the 35 years after
initial intake;4
[p. 14]
(7) information from large populations on the correlation between the
average background body burden of radium and the natural population inci-
dence of osteogenic sarcoma; and
(8) uncertainties in the RBE for alphas on chronic exposure.
2.55 There is no evidence to establish definitely the presence or
absence of a threshold for the effects of radium deposition in bone.
However, the first appearance of minimal radiographic changes in
bones of adults exposed to radium occurs with a residual body
burden (measured several decades after exposure) of the order of
0.2 microgram. Whether this effect is attributable to radium is in
doubt because of the absence of matched age group controls.
There seems to be no doubt that, at 0.5 microgram burden, changes
in adult bones, shown by radiographs, are manifest in some in-
dividuals. Radiographic changes are always seen above 0.8 micro-
gram, and there is agreement that bone tumors begin to occur at
about a burden of 0.8 to 1.0 microgram. Teeth changes were noted
in a young person with a body burden of 0.15 microgram. Within
the limits of the time duration for the effect and the relatively
small numbers of individuals studied, there is a range of radium
body burdens within which any specific clinically significant effect
occurs. The body burdens among individuals with a given effect
appear to be statistically normally distributed. At increasing
burdens the curve of body burden against effect follows a steeply
rising slope. At body burdens below 0.1 microgram, which is the
area of our interest, prediction is hazardous.
2.56 It would appear that current radium studies (among the
4 Some recent data suggest that, for oial intake of radium waters, the measured body burden
of humans drinking the waters is about one-sixth of the body burden predicted by cuirently used
biological models.
-------
1020 LEGAL COMPILATION—RADIATION
groups described in paragraph 2.50) may have a maximum num-
ber of about 2,000 persons available for body burden measure-
ments. These numbers may be insufficient on a statistical basis to
assure extrapolation of the probability of occurrence of an effect
to the general population. It remains to be demonstrated whether
or not, on an individual basis, the diagnostic methods used on hu-
mans can show "damage" below 0.1 microgram. This is true even
if one studies a larger number of individuals, particularly if the
group is composed of children with differential sensitivity or of
older persons with intercurrent infections or increased bone fra-
gility. It is hoped that pertinent data on the question of threshold
will be forthcoming from animal studies. There is suggestive
evidence that the length of the latent period for the development
of "clinically significant findings" may increase as the body burden
decreases. If this be true, depending on the age of the animal, the
latent period may be greater than the remaining lifetime of the
animal.
2.57 With other bone seeking radionuclides there are not as
extensive data in man on biological effects as for radium. There-
fore, it has become the custom to relate the biological effects of
other bone seeking radionuclides to those of radium. Evidence for
the relationships has been obtained at high doses in animals. For
example, mouse experiments showed the ratio of body burden of
radiostrontium to radium for the same tumor induction to be ap-
proximately 10 to 1. However, newer biological data in man on
the skeletal escape and excretion of the radium daughter radon
require further adjustment in the ratio when it is applied to man.
Although bone tumors have been produced by radiostrontium in
animals, it should be noted that no cases of bone tumors have been
demonstrated in man as due to strontium-90.
LIFE SPAN SHORTENING
2.58 Radiation exposure does not produce in the individual a
pattern of effects specific to radiation. Life span shortening has
been demonstrated in animals by comparisons of mean life span
between exposed and nonexposed groups. This involves observa-
tions continued to death of the cohorts of the irradiated individuals
while controlling the intercurrent factors which might affect the
study groups.
2.59 The experimental evidences of radiation effect on life span
in animals includes:
(1) Exposure of animals to chronic high doses, in general, decreases their
life span. A plot of the percentage survival vs. time yields an S shaped curve
in both the exposed group and the unexposed controls. The mean survival time,
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GUIDELINES AND REPORTS 1021
however, is shortened in the exposed group to the total dose. While the evi-
dence is not conclusive, it appears that in mice the mean life span is lengthened
at very low dose rates, at a total dose of about 100 r. However, in every piece
of experimental evidence (except at about the 100 r level in animals described
above) there is life span shortening- at dosages above approximately 100-300 r
total body dose. At such dosages the life span shortening in mice is in the order
[p. 15]
of 1 to 1.5 percent of total life span per 100 r total dose. The evidence for
linearity of the dose-effect curve in other species (dogs) rests on only a few
animals and, again, at doses greater than 100 r. There is suggestive evidence
that protracted doses above 200 r have a lesser effect than a single acute dose.
With protracted radiation, in some experimental animals, it appears that there
is some life shortening from the range of 200 to 100 r, but that the chronic radia-
tion is about 4 to 5 times less effective per r than a single very large dose. For
radiations other than x- or gamma-rays the RBE for this effect is uncertain.
(2) A decrease in the median lethal dose is observed when pre-irradiated
animals are exposed to a second course of irradiation in comparison to controls
not previously irradiated. This decrease in the LD,->n depends upon the elapsed
time between first and second exposure.
2.60 The facts concerning acute injury and delayed effects de-
scribed above might lead to the following assumptions; viz:
(1) The total injury produced by radiation varies linearly with the dose.
(2) Partial recDvery from acute injury occurs, but an irreparable effect
remains.
(3) Recovery from reparable injury is an exponential process. The recovery
rate varies with the dose rate and whether the exposure is whole body or partial
body. The exponential rate of recovery following acute exposure is the cumu-
lative expression of the fact that different parts of the body repair at different
rates.
(4) Irreparable injury is accumulated in proportion to the total dose. It
may be measured by life shortening, or, for experimental purposes, by a reduc-
tion in the median lethal dose. Residual injury of irradiation occurs irrespec-
tive of the age of the animal when irradiation is begun.
2.61 Examination of the specific causes of death shows that the
same causes of death, apart from tumors, occur generally in the
same proportion but sooner in the irradiated than in the un-
irradiated individuals. It is to be noted that observations are
sometimes made of some muscular impairment or accumulation
of connective tissue, but these cannot be quantitated. Studies of
performance tests may shed more light on this.
2.62 The effects from large acute exposure may conform to the
assumptions outlined above but all of these assumptions may not
be applicable to the effects of a chronic daily dose of 1 r. Lacking
in our knowledge is a formulation of indices of recovery following
irradiation at these low levels. The experimental use of the me-
dian lethal dose to measure recovery requires pre-irradiation doses
of at least 40-50 r to yield definitive data with reasonable numbers
of animals.
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1022 LEGAL COMPILATION—RADIATION
2.63 Little is known of the nature of the pathological process
responsible for life shortening. One theory considers, by analogy
to genetic mutations, that the accumulation of radiation injury to
the somatic cell chromosomes leads to reproductive death of a
somatic cell. This process occurring in a large number of cells
may be responsible for the aging of an organism. In the present
state of knowledge it is premature to attribute the complex proc-
esses of aging to somatic mutations. It seems that extensive
studies of the causes of death shown by animal experiments and
human surveys may further our knowledge of chronic radiation
effects in man.
2.64 In humans the evidence for life span shortening is limited.
Mortality studies among U.S. physicians, comparing the effects
of occupational exposure of radiologists with other physicians and
with the general male population, have not produced definitive
answers to the question of whether a decrease in life span occurred
in the radiologists. For the general population, estimations of a
non-specific life shortening effect from whole body radiation con-
tinues to be based on experiments on animals exposed to large
doses. There are as yet no data in man to answer the questions
of quantitative estimates of life shortening effect per rad of whole
body exposure. Equally in question are the existence of a thresh-
old dose, or the dose fractionation effect for exposures commonly
experienced by the general population.
[p- 16]
GROWTH AND DEVELOPMENT
2.65 Only a portion of developmental defects are attributable to
genetic origins. It is necessary to distinguish within the totality
of congenital defects, those attributable to changes in the genetic
material; and of the latter, those which may be due to environ-
mental causes, including radiation. Some geneticists estimate that
10 percent of fertilized ova have some congenital defect (malfor-
mation) detectable during that generation. Of this 10 percent,
about 0.1 are ascribed to an environmental insult to the developing
fetus (such as rubella and other viruses, toxic chemica'ls, maternal
nutritional disturbances, radiation, etc.); about 0.1 are clearly due
to simple mendelian genetic systems; and about 0.1 are due to
chromosomal aberrations of a particular type. The great bulk of
the remaining 0.7 are believed to be due to complex genetic systems
whose expression depends on environmental variables operating on
alterations of the homeostatic balances of life. Radiation may be
one of a myriad of possible causes of congenital defects.
2.66 In animals, effects of radiation on prenatal embryonic de-
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GUIDELINES AND REPORTS 1023
velopment have been demonstrated from 25 r to several hundred
r or more, and are closely correlated with the time of gestation at
which radiation is given. The prenatal effects include (1) failures
of uterine implantation leading to a maternal missed period, or to
miscarriages and stillbirths; (2) alterations induced in the varying
stages of development of fetal organs which lead to a high neo-
natal death rate and abnormalities at term; and (3) late stage
manifestations, such as subtle changes in physiological states.
2.67 Parts of the human brain and eye are probably susceptible
to injury until the last months of gestation. In mice, acute doses
of 25-30 r (whole body x-rays) to the fetus produce discernible
skeletal defects. It is known from bone studies on human still-
births that radiostrontium may pass through the placental barrier
and become fixed in the skeleton and other organs. It is pre-
sumed that exposure of this type may in the early stages of the
growing embryo resemble whole body exposure.
2.68 Effects of irradiation on postnatal development are also
described. Although it is known that regeneration and repair
processes are sensitive to radiation, more quantitative studies
under conditions of whole or partial body exposure are needed.
In rats, quantitative studies show that growth in body weight is
decreased as a result of about 24 r per week whole body irradia-
tion. Localized irradiation of the epiphysis of bones at high doses
in humans and animals will cause measurable shortening of the
bones. Studies on children exposed to the atomic bomb in Japan
indicate that there may be depression of growth rates after ir-
radiation as has been observed in animals. However, little is
known in either animals or humans of the after-effects of whole or
partial body irradiation in the young in comparison to mature
animals, and of the subtle changes induced in their physiological
efficiency.
SKIN EFFECTS
2.69 Knowledge of effects to the skin of localized exposure to
radiation of low penetrating power has accumulated since the dis-
covery of x-rays. The early promulgation of a "tolerance dose"
of x-radiation was established by quantitating skin reactions
(erythema) with dose. Among early radiologists the chronic ra-
diation produced erythema, dermatitis, and skin cancers. Under
modern practices, these conditions should no longer be seen.
EYE EFFECTS
2.70 Injury to the lens serves as a sensitive detecting index of
the effect of radiation on the eye. Lens opacities (cataracts) have
-------
1024 LEGAL COMPILATION—RADIATION
occurred following exposure of the eye in animals (exposed to
neutrons and x-rays), and cyclotron workers, nuclear physicists,
and Japanese survivors at Hiroshima and Nagasaki. In man, the
minimal single dose producing cataracts is estimated to be ap-
proximately 200 rads acute exposure of x- or gamma-rays. In
animals the production of cataracts depends on the age and health
of the animal, the exposed lens area, and the RBE of the source
[p. 17]
of radiation. There are no quantitative dose-effect data relating
the incidence of cataracts late in life in humans or animals to the
acceleration of aging processes.
SUMMARY
1. Acute doses of radiation may produce immediate or delayed
effects, or both.
2. As acute whole body doses increase above approximately 25
rems (units of radiation dose), immediately observable effects in-
crease in severity with dose, beginning from barely detectable
changes, to biological signs clearly indicating damage, to death at
levels of a few hundred rems.
3. Delayed effects produced either by acute irradiation or by
chronic irradiation are similar in kind but the ability of the body
to repair radiation damage is usually more effective in case of
chronic than acute irradiation.
4. The delayed effects from radiation are in general indistin-
guishable from familiar pathological conditions usually present in
the population.
5. Delayed effects include genetic effects (effects transmitted to
succeeding generations), increased incidence of tumors, life span
shortening, and growth and development changes.
6. The child, the infant, and the unborn infant appear to be
more sensitive to radiation than the adult.
7. The various organs of the body differ in their sensitivity to
radiation.
8. Although ionizing radiation can induce genetic and somatic
effects (effects on the individual during his lifetime other than
genetic effects), the evidence at the present time is insufficient to
justify precise conclusions on the nature of the dose-effect rela-
tionship especially at low doses and dose rates. Moreover, the
evidence is insufficient to prove either the hypothesis of a "damage
threshold" (a point below which no damage occurs) or the hy-
pothesis of "no threshold" in man at low doses.
9. If one assumes a direct linear relation between biological
effect and the amount of dose, it often becomes possible to relate
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GUIDELINES AND REPORTS 1025
very low dose to an assumed biological effect even though it is not
detectable. It is generally agreed that the effect that may actually
occur will not exceed the amount predicted by this assumption.
[p. 18]
III. SOURCES OF RADIATION EXPOSURE
3.1 For convenience, the exposure of persons to radiation will
be divided into three classes: (a) exposures from natural sources;
(b) exposures from man-made sources other than environmental
sources; and (c) exposures from environmental contamination.
Where data are available, the exposures of various critical por-
tions of the body are indicated separately. Of special interest are
the gonadal dose because of its genetic significance and the bone
marrow dose because of possible leukemogenesis. Therefore, the
following discussions center their attention on the genetically sig-
nificant and bone marrow doses as examples of the general
problem.
NATURAL SOURCES
3.2 Table 3.1 lists the doses received by persons in the United
States from natural sources. The principal exposures from ra-
diation sources outside of the body (external sources) and from
sources inside of the body (internal sources) are listed separately.
3.3 The dose from cosmic rays for 38 principal cities in the
United States was determined from data on the variation of cosmic
ray dose with altitude ' (Solon et al—1959). As most of the large
centers of population are near sea level, the mean dose to the
population of the United States from cosmic rays is nearer the
lower than the upper limit.
3.4 The dose from terrestrial external gamma rays was esti-
mated by subtracting the cosmic ray component from measure-
ments of the sum of the two components (Solon et al, 1959) and
applying an approximate correction (0.6) for the average shield-
ing of the outer tissues of the body. The resulting range of values
includes mean values for 38 of the principal cities of the United
States. However, it should be noted that doses obtained at differ-
ent locations within a city varied in several cases by a factor of
2 or 3 for the limited data available. In part, this may be due to
shielding of heavy structures or the proximity of structures whose
building materials contained small quantities of gamma emitting
nuclides. '
1 Variation of the dose from cosmic rays with latitude is small compared to that with altitude.
-------
1026 LEGAL COMPILATION—EADIATION
3.5 When doses from internal sources are added, it appears
(Table 3.1) from the limited data available that the radiation dose
to soft tissue from all natural sources varies by at least a factor
of 2 in the United States.
MAN-MADE SOURCES OTHER THAN ENVIRONMENTAL
CONTAMINATION
3.6 Exposure of persons to man-made radiation other than en-
vironmental contamination arises principally from (1) exposures
received during medical procedures, (2) exposures received by
radiation workers during their working hours, (3) exposures to
persons in the vicinity of medical and industrial radiation sources
(environs), and (4) exposure produced by other sources, such as
radium dialed watches, television sets, etc. Table 3.2 summarizes
the estimated per capita mean marrow doses and genetically sig-
nificant doses to the population from man-made sources other than
environmental contamination. The per capita dose is the sum of
all of the doses received by the population divided by the number
of individuals in the population. The annual genetically signifi-
cant dose to the population is the average of the gonadal doses
received by the individuals each weighted for the expected number
of children to be conceived subsequent to the exposure.
3.7 For the occupational exposure it is assumed that as much as
a half of one per cent of the population might be exposed in the
future to as much as an average annual dose of 4 rems. Both
estimated figures are high because the fraction of the population
occupationally exposed to radiation and the annual dose they re-
[P. 19]
ceive at the present time is considerably less than that assumed in
Table 3.2. There are presently only about 66,000 radiation work-
ers out of a total employment approximating 120,000 in the Atomic
Energy Commission and its contractors (see Table 5.1) and per-
haps 250,000 persons occupationally exposed to x-rays in medical
application. Persons in these two areas plus the industrial radiog-
raphy field probably do not constitute more than 0.2 per cent of the
population at the present time. Morgan (1959) indicates that the
average annual exposure of radiation workers at Oak Ridge Na-
tional Laboratory is 0.4 r, and at Hanford, 0.2 r (see Table 5.1).
In the fields of medical applications and industrial radiography,
the annual doses received by most radiation workers falls within
the range of 0.5 to 5 rems. Most of them probably receive doses
in the lower half of this range but a few possibly receive more than
5 and some less than 0.5 rems. Thus, the average annual dose for
-------
GUIDELINES AND REPORTS 1027
all radiation workers is probably much less than the 4 rems as-
sumed for the calculation at the present time.
3.8 For exposure of persons in the environs it is assumed that
one per cent of the population might be involved and they would
have an annual dose of as much as 0.5 rems. This assumption
concerning per capita dose from the exposure of environs is prob-
ably larger than will be obtained in the foreseeable future. The
fraction of the population assumed is quite large and it is unlikely
that the average individual will receive as much as 0.5 rem per
year.
3.9 Unfortunately, there are no data on the mean marrow dose
from medical therapy, but it is obvious that diagnostic x-rays con-
tribute considerably to the total exposure from man-made sources
other than environmental contamination. While diagnostic x-rays
are an important clinical tool, the practitioner of the healing arts
should always attempt to balance the risk against the gain for each
exposure. He should also assure himself that the most modern
techniques are being used in order that the dose is reduced as much
as practicable. Current recommendations of the NCRP (H54,
1954 and H60, 1955) indicate methods by which the gonadal dose
can be minimized. If these recommendations are observed the
bone marrow dose will also be minimized.
MAN-MADE ENVIRONMENTAL CONTAMINATION
3.10 Sources of environmental contamination may result from
fallout after the explosion of nuclear devices and during the use
and processing of fuels for reactors. There are other sources
which contribute relatively smaller amounts to environmental
contamination.
3.11 Environmental contamination from fallout has received
considerable attention over the past decade. When there is a nu-
clear explosion in the megaton range, the gases cool so slowly that
a major portion of the fission products enter the stratosphere
where they are distributed widely. Some fission products drift
back into the troposphere before losing their radioactivity and are
deposited in patterns which depend at least in part upon me-
teorological conditions. This final fallout, however, takes a long
time to drift back to earth so that the fission products from this
stratospheric source consist mainly of the long-lived nuclides. For
nuclear explosions in the kiloton range, the heat of the fireball is
considerably less so that the fission products do not reach the
stratosphere but stay in the troposphere. About half of the radio-
active material from the troposphere comes back to the earth in
about three weeks and most of the fallout reaches the earth in
-------
1028 LEGAL COMPILATION—RADIATION
about three months (UNSCEAR p. 99, 1958). From such a fall-
out, many of the nuclides are of short half-life.
3.12 According to reported estimates,- the genetically significant
per capita dose in the United States from both external and
internal radiation from fallout of cesium-137 will be about 53 mil-
lirem in 30 years providing nuclear weapons testing in the atmos-
phere is not resumed after the cessation at the end of 1958. It
was also reported that the per capita mean marrow dose in the
United States would be, under the same conditions, about 331
millirem in 70 years from cesium-137 and strontium-90. For con-
tinued testing at the same rate as in the previous 5 years, it was
estimated that the above numbers should be multiplied by a factor
of 8. Other estimates (UNSCEAR 1958 and Feeley 1960) are
somewhat lower.
[p. 20]
3.13 Under normal operating conditions, most industries in the
nuclear engineering field, including the use of reactors, do not now
release activity which will give significant contributions to the
population dose.
3.14 It is usually considered very unlikely that the core of a re-
actor would melt down accidentally and release fission products.
This possibility, however remote, is considered in designing a
reactor. Modern reactors are designed with a containment shell
which would permit only a very small portion of the fission prod-
ucts, from a melt-down, to contaminate the environment. How-
ever, according to the best engineering estimates, this and other
containment provisions will not trap all of the activity. An ad-
ditional major reduction in the activity released by the shell would
substantially increase the cost of the reactor.
3.15 Plants used for the processing of spent fuel elements have
a larger potential for contaminating the environment. Here the
fuel element is dissolved and the radioactive material is liberated
from the fuel element. However, the amount of material treated
at any one time is much less than the material present in a reactor.
In this process, fission product gases, such as radioactive iodine,
bromine, xenon, and krypton are released from the fuel element.
Most of the other radionuclides remain in the solutions. Some
nuclides, such as cesium-137 and strontium-90, may be separated
out for other uses. The remainder of the radionuclides are now
stored in huge tanks. Such storage is, of course, expensive.
2W. Langham and E. C. Anderson, Fallout from Nuclear Weapons Tests, Hearings of the Joint
•Committee on Atomic Energy, Congress of the United States, May 1959, p. 1061 ft.
-------
GUIDELINES AND REPORTS 1029
SUMMARY
3.16 From a limited survey it appears that the human annual
gonadal, soft tissue, and bone marrow doses from natural sources
may be from 80 to 170 millirem (see Table 3.1).
3.17 The estimated annual genetically significant dose from all
man-made sources except environmental contamination probably
is about 80 to 280 millirem. The per capita annual mean marrow
dose is probably greater than 100 millirem, although no data are
available on the contribution from medical radiation therapy. The
genetically significant dose and the mean marrow dose are each
of the order of the dose received from natural sources. Diagnostic
x-rays provide a substantial contribution to these totals (see
Table 3.2).
3.18 It has been estimated ' that fallout will contribute about
53 millirem to the genetically significant per capita dose of the
population in 30 years if nuclear weapons testing in the atmos-
phere is not resumed after the cessation at the end of 1958. If
testing were to continue at the same rate as in the previous 5
years, it was estimated that the above number should be multiplied
by a factor of 8. The estimated corresponding per capita mean
marrow doses for 70 years are 331 millirem and 2648 millirem
respectively.
3.19 Under normal operating conditions, most industries in the
nuclear engineering field, including the use of nuclear power plants
do not now release activity which will give a significant contribu-
tion to the population dose.
[P. 21]
TABLE 31—ANNUAL RADIATION DOSES' FROM NATURAL SOURCES
Irradiation Millirem
By external sources:
Cosmic rays 32-73
Terrestrial gamma rays 25-75
By internal sources:
K<° 2 19
C'< 21.6
Ra224 3 ?
Total 4 80-170
1 Doses to the gonads and other soft tissue including bone marrow.
2 Report of United National Scientific Commission on the Effects of Atomic Radiation (UNSCEAR, p. 58,
1958).
3 Unconfirmed research of Muth et al, Brit. J. of Radiol. Suppl. No. 7, 1957, indicates that the dose
may be of the order of 2 miilirem per year to the gonads and 5 to 15 millirem per year to ot'ier soft tissue.
' The lungs may receive an additional dose of from 125 to 1570 millirem per year from radon given off
by building structures. The spread is caused by variations in ventilation and differences in building
materials (UNSCEAR, p. 58, 1958).
•;W. Langham and E. C. Anderson, Fallout From Nuclear Weapons Tests, Hearings of the Joint
Committee on Atomic Energy, Congress of the United States, May 1959, p. 1061 ff.
-------
1030
LEGAL COMPILATION—RADIATION
TABLE 32.—ESTIMATED EXPOSURE FROM MAN-MADE SOURCES' (OTHER THAN
ENVIRONMENTAL CONTAMINATION)1
Irradiation
Medical (exposure of patients):
Therapy
Internal (radionuchdes)
Environs
Other (luminous dials, TV, etc.)
Total .
Average annual geneti-
cally significant dose
to the population
(millirem)
2 3 40 240
5 12
5 1
20
5
6 2
80 280
Per capita annual
mean marrow dose
(millirem)
4 50 100
10
20
5
'1-3
1 Fallout from tests of nuclear weapons is not included (see sub-section on environmental contamination).
2 Internationa] Commission on Radiological Protection (ICRP) and International Commission on Radio-
logical Units and Measurements (ICRU) Joint Study Group Report. Physics in Med. and Biology, 2 107
(1957).
3 These are probable values.
4 Report UNSCEAR, p. 66.
5 Clark, S. H., Bull, of the Atomic Scientists 12 14 (1956). The 12 millirem per year may be an
underestimate because patients treated for malignancies are not included. Martin (1958), who assumed
that these patients might procreate after treatment, obtained a value of 28 for Australia.
Report of UNSCEAR, p. 11.
[p. 22]
SECTION IV.—THE DERIVATION OF RADIATION PROTECTION
STANDARDS
4.1 Shortly after the discovery of x-rays and natural radio-
activity in the late 19th century, it became apparent that exposure
to sufficiently large doses could produce both acute manifestations
and serious later sequelae in man. Based on relatively limited
observations on a rather small number of individuals, attempts
were made to define a level at which these obvious deleterious ef-
fects would not be seen. With increasing scientific knowledge,
based on observations of larger numbers of individuals and lab-
oratory animals and a better understanding of radiation damage,
these suggested levels have undergone continuous downward re-
vision. For some time, however, the underlying basic philosophy
remained unchanged, and radiation protection standards were
based on the premise that there was a dose ("tolerance dose")
below which damage would not occur. The validity of this basic
assumption was subject to increasing question, first in the field of
genetic damage, and later in connection with somatic effects.
Thus, by 1954, the National Committee on Radiation Protection
and Measurements included the following statement in Handbook
59 (NCRP, H59, 1954):
"The concept of a tolerance dose involves the assumption that if the dose is
-------
GUIDELINES AND REPORTS 1031
lower than a certain value—the threshold value—no injury results. Since it
seems well established that there is no threshold dose for the production of gene
mutations by radiation, it follows that strictly speaking there is no such thing
as a tolerance dose when all possible effects of radiation on the individual and
future generations are included . . ." and ". . . the concept of a permissible dose
envisages the possibility of radiation injury manifestable during the lifetime
of the exposed individual or in subsequent generations. However, the probabil-
ity of the occurrence of such injuries must be so low that the risk would be
readily acceptable to the average individual. Permissible dose may then be de-
fined as the dose of ionizing radiation that, in the light of present knowledge, is
not expected to cause appreciable bodily injury to a person at any time during
his lifetime. As used here, 'appreciable bodily injury' means any bodily injury
or effect that the average person would regard as being objectionable and/or
competent medical authorities would regard as being deleterious to the health
and well-being of the individual . . ."
4.2 With the accumulation of even more quantitative informa-
tion concerning radiation effects in both animals and humans, and
some increased understanding of the mechanisms of radiation in-
jury, the possibility that somatic effects as well as genetic effects
have no threshold appeared acceptable, as a conservative assump-
tion, to increasing numbers of scientists. In discussing its recom-
mendations for additional downward revision of the maximum
permissible occupational radiation exposure, the NCRP in 1958
stated (2):
"The changes in the accumulated MPD (maximum permissible dose) are not
the result of positive evidence of damage due to the use of earlier permissible
dose levels, but rather are based on the desire to bring the MPD into accord with
the trends of scientific opinion; it is recognized that there are still many uncer-
tainties in the available data and information . . . ," and, "The risk to the indi-
vidual is not precisely determinable but, however small, it is believed not to be
zero. Even if the injury should prove to be proportional to the amount of radia-
tion the individual receives, to the best of our present knowledge, the new per-
missible levels are thought not to constitute an unacceptable risk . .."
4.3 Thus, over the past decade or two, there has been an in-
creasing reluctance on the part of knowledgeable scientists to
establish radiation protection standards on the basis of the exist-
ence of a threshold for radiation damage and on the premise that
this threshold lies not too distant from the point at which impair-
ment is detectable in an exposed individual. Although many sci-
entists are prepared to express individual opinions as to the
likelihood that a threshold does or does not exist, we believe that
there is insufficient scientific evidence on which to base a definitive
conclusion in this regard. Therefore, the establishment of radia-
tion protection guides, particularly for the whole population, should
take into account the possibility of damage, even though it may
[P. 23]
-------
1032 LEGAL COMPILATION—RADIATION
be small, down to the lowest levels of exposure. This involves
considerations other than the presence of readily detectable dam-
age in an exposed individual. It also serves as a basis for such
fundamental principles of radiation protection as: there should
not be any man-made radiation exposure without the expectation
of benefit resulting from such exposure; activities resulting in
man-made radiation exposure should be authorized for useful ap-
plications provided the recommendations set forth in this staff
report are followed.
4.4 If the presence of a threshold could be established by ade-
quate scientific evidence, and if the threshold was above the back-
ground level and sufficiently high to represent a reasonable working
level, a relatively simple approach to the establishment of radiation
standards would be available.
4.5 On the assumption that there is no threshold, every use of
radiation involves the possibility of some biological risk either to
the individual or his descendents. On the other hand, the use of
radiation results in numerous benefits to man in medicine, in-
dustry, commerce, and research. If those beneficial uses were
fully exploited without regard to radiation protection, the result-
ing biological risk might well be considered too great. Reducing
the risk to zero would virtually eliminate any radiation use, and
result in the loss of all possible benefits.
4.6 It is therefore necessary to strike some balance between
maximum use and zero risk. In establishing radiation protection
standards, the balancing of risk and benefit is a decision involving
medical, social, economic, political, and other factors. Such a
balance cannot be made on the basis of a precise mathematical
formula but must be a matter of informed judgment.
4.7 Risk can be evaluated in several different ways before it is
balanced against benefit. A logical first step is the identification
of known or postulated biological effects. The uncertainty of our
present knowledge is such that the biological effects of any given
radiation exposure cannot be determined with precision, so it is
usually necessary to make estimates with upper and lower limits.
4.8 It is helpful to compare radiation risk to other known haz-
ards in order to maintain perspective or a sense of proportion with
respect to the risk. For example, attempts have been made to
compare the relative biological risks of various radiation exposure
levels to such other industrial hazards as traumatic injuries and to
toxic agents employed in industrial processes. Likewise, the
possible hazards from various radiation levels have been reviewed
in relation to such everyday risks to the general population as the
operation of -motor vehicles, the possibility of home accidents, and
-------
GUIDELINES AND REPORTS 1033
the contamination of our environment with industrial wastes.
4.9 Effects can also be evaluated in terms of the normal in-
cidence of disease conditions usually present in the population
which may also be caused by radiation. In a given instance, the
portion of the total number of cases of a given disease which might
be attributed to radiation may be quite small. Therefore, the sig-
nificance of a given radiation exposure can appear superficially to
be quite different depending upon whether the data are expressed
in terms of the absolute numbers of cases of a given condition
which will possibly result, or be expressed as percentages of the
normal incidence. However, it is extremely difficult to assign any
numerical value to the increase which should be permitted in a
given abnormal condition. It is also important to remember that
at the present time, any numerical predictions of the number or
percentage increase in any given condition anticipated as a result
of radiation exposure are based on inadequate data and have ex-
tremely limited reliability, even though upper and lower limits
can be stipulated.
4.10 The biological risk attributable to man-made radiation may
also be compared with that from natural sources. This approach
is also important in maintaining perspective. Man and lower
forms of life have developed in the presence of such natural
sources in spite of any radiation damage that may have been
present. Perhaps one of the more important advantages to this
approach is that it makes due allowance for qualitative as well as
quantitative ignorance of yet unrecognized radiation effects, if
such exist. Weighing for various somatic as well as genetic ef-
fects is also inherently included. It automatically includes a con-
sideration of the largest body of human and subhuman data on
radiation effects. One disadvantage is the degree of conservatism
[p. 24]
introduced by this approach, since it is likely that only a small
fraction of the total incidence of disease results from background
radiation.
SUMMARY
4.11 Two factors need to be considered in the formulation of
radiation protection standards: biological risk, and the benefits to
be derived from radiation use. Maximum benefits cannot be ob-
tained without some risk, and risk cannot be eliminated without
foregoing benefits. Therefore some balance must be struck be-
tween risk and benefit.
4.12 Since an accurate delineation of risk is impossible, a num-
ber of approaches can usefully be employed to aid in the evaluation
-------
1034 LEGAL COMPILATION—RADIATION
of risk, and to put risk in reasonable perspective. Each has merit,
but such approaches are not mutually exclusive and should be used
in combination. An evaluation of benefits in addition to an evalu-
ation of risk is also necessary.
[p. 25]
SECTION V.—BASIC GUIDES
5.1 The philosophical bases for derivation of radiation protec-
tion standards have been discussed in Section IV, with the con-
clusion that they are not mutually exclusive, and that consideration
should be given to all in the final selection of numerical values.
We believe, however, that there are reasons why the relative
emphasis placed on the various bases may appropriately be dif-
ferent for the radiation worker and the general population. Ad-
ditionally, there appear to be a number of reasons why the exposure
to the general population should be less than that for occupationally
exposed groups. For example:
(1) There is reason to believe that the child and the infant may be particu-
larly sensitive to radiation damage. Children and infants are not included in
occupationally exposed groups.
(2) The number of years of exposure to radiation in the course of employ-
ment will be less than the average total life span. Therefore, the total accumu-
lated dose will be less for an individual exposed only during a working life than
for an individual exposed at the same level from birth through a normal life
span to death.
(3) There is considerable evidence that, at least for certain effects, there is
a latent period between the time of exposure and the time at which effects are
first detectable. The effects of exposure late in life may not become manifest
during the normal remaining life span. Whereas, the effects of exposure early
in life may well become manifest during the longer remaining life span.
(4) Industrial workers undergo at least some degree of preplacement selec-
tion. It is thus possible to exclude from exposure those individuals with inter-
current disease who might be more susceptible to injury.
(5) Insofar as an individual has a choice of occupations, there is, at least in
principle, voluntary acceptance of the small risk potentially involved.
(6) Considerations of population genetics make it desirable to limit gonadal
exposure of the whole population.
RADIATION PROTECTION GUIDES FOR THE GENERAL POPULATION T
5.2 We believe that the current population exposure resulting
from background radiation is a most important starting point in
the establishment of Radiation Protection Guides for the general
population. This exposure has been present throughout the his-
tory of mankind, and the human race has demonstrated an ability
to survive in spite of any deleterious effects that may result.
Radiation exposures received by different individuals as a result
1 See Section VII for applicability of these guides.
-------
GUIDELINES AND REPORTS 1035
of natural background are subject to appreciable variation. Yet,
any differences in effects that may result have not been sufficiently
great to lead to attempts to control background radiation or to
select our environment with background radiation in mind.
5.3 On this basis, and after giving due consideration to the other
bases for the establishment of Radiation Protection Guides, it is
our basic recommendation that the yearly radiation exposure to
the whole body of individuals in the general population (exclusive
of natural background and the deliberate exposure of patients by
practitioners of the healing arts) should not exceed 0.5 rem. We
note the essential agreement between this value and current rec-
ommendations of the ICRP and NCRP. It is not reasonable to
establish Radiation Protection Guides for the population which
take into account all possible combinations of circumstances.
Every reasonable effort should be made to keep exposures as far
below this level as practicable. Similarly, it is obviously appropri-
[P. 26]
ate to exceed this level if a careful study indicates that the prob-
able benefits will outweigh the potential risk. Thus, the degree of
control effort does not depend solely on whether or not this Guide
is being exceeded. Rather, any exposure of the population may
call for some control effort, the magnitude of which increases with
the dose.
5.4 Under certain conditions, such as widespread radioactive
contamination of the environment, the only data available may be
related to average contamination or exposure levels. Under these
circumstances, it is necessary to make assumptions concerning the
relationship between average and maximum doses. The Federal
Radiation Council suggests the use of the arbitrary assumption
that the majority of individuals do not vary from the average by
a factor greater than three. Thus, we recommend the use of 0.17
rem for yearly whole-body exposure of average population groups.
(It is noted that this guide is also in essential agreement with cur-
rent recommendations of the NCRP and the ICRP.) It is critical
that this guide be applied with reason and judgment. Especially,
it is noted that the use of the average figure, as a substitute for
evidence concerning the dose to individuals, is permissible only
when there is a probability of appreciable homogeneity concerning
the distribution of the dose within the population included in the
average. Particular care should be taken to assure that a dis-
proportionate fraction of the average dose is not received by the
most sensitive population elements. Specifically, it would be in-
appropriate to average the dose between children and adults,
especially if it is believed that there are selective factors making
-------
1036 LEGAL COMPILATION—RADIATION
the dose to children generally higher than that for adults.
5.5 When the size of the population group under consideration
is sufficiently large, consideration must be given to the contribution
to the genetically significant population dose. The Federal Radi-
ation Council endorses in principle the recommendations of such
groups as the NAS-NRC, the NCRP, and the ICRP concerning
population genetic dose, and recommends the use of the Radiation
Protection Guide of 5 rem in 30 years (exclusive of natural back-
ground and the purposeful exposure of patients by practitioners
of the healing arts) for limiting the average genetically significant
exposure of the total U.S. population. The use of 0.17 rem per
capita per year, as described in paragraph 5.4 as a technique for
assuring that the basic Guide for individual whole body dose is not
exceeded, is likely in the immediate future to assure that the
gonadal exposure Guide is not exceeded. The data in Section III
indicates that allocation of this population dose among various
sources is not needed now or in the immediate future.
RADIATION PROTECTION GUIDES FOR OCCUPATIONAL EXPOSURE 2 3
5.6 Extrapolation from experience with background radiation
to the exposure of the relatively small percentage of the population
in the radiation industry is rather unsatisfactory. The difficulties
inherent in a careful mathematical balancing of the biological
risk against the total gain have been outlined previously. It is
possible to estimate the maximum biological damage which could
be reasonably expected to result from a given radiation exposure.
Using such estimates, a numerical value can be selected at which
the radiation risk appears so small as to be justified by even a
relatively minor benefit. The NCRP recommends that, for occu-
pational exposure, the radiation dose to the whole body, head and
trunk, active blood forming organs, or gonads, accumulated at any
age, shall not exceed 5 rems multiplied by the number of years
beyond age 18, and that the dose in any 13 consecutive weeks shall
not exceed 3 rems. The Federal Radiation Council agrees with
the opinion of the NCRP that this dose of ionizing radiation is not
expected to cause appreciable body injury to a person at any time
during his lifetime. Thus, while the possibility of injury may exist
at this dose, the probability of detectable injury is almost certain
to be extremely low. Even the use of the more pessimistic as-
sumptions would indicate that the small risk involved is acceptable
- See Section VII for applicability of these guides.
" In the formulation of*Radiation Protection Guides for occupational exposure, special considera-
tion has not been given in this staf • tort to the possible existence of pregnancy among female
•workers.
-------
GUIDELINES AND REPORTS 1037
if the gain is of any significance. Fortunately, this level also
appears to be one which is not unduly restrictive in ordinary work-
ing circumstances.
5.7 There will be individual circumstances under which compli-
ance with this guide would not be feasible. For example, accidents
will occur, but the dose received will usually be determined by the
[p. 27]
nature and conditions of the accident and consequently, the dose
does not lend itself to prior planning. In addition to accidents,
emergency situations will almost certainly arise, but here too, the
dose should be determined by the nature of the emergency.
5.8 It is recognized that, even though small, there is a possibility
of biological damage to the individual or his progeny from ex-
posures of less than 5 rem per year. For this reason, radiation
exposures should always be maintained at the minimum practic-
able level. Thus, it seems inadvisable to expose man to radiation
if no benefit is anticipated.
5.9 It is to be noted that these recommendations are expressed
in terms of rem. While the rad is the basic unit in physical
dosimetry, some adjustment for the relative damage produced,
even in the same individual, by one rad of gamma-rays as com-
pared to one rad of alpha-rays, for example, must be included.
(For a definition of terms and a list of RBE conversion factors,
refer to Section I.) Because the value for the RBE may change
with newer scientific knowledge, and in view of the relative
importance of the total accumulated dose throughout a worker's
lifetime, agencies and departments may wish to consider the
desirability of maintaining exposure records in such a fashion that
recalculation of the accumulated dose in rem can be made at any
time when changes in the RBE are justified. One technique would
be to keep primary exposure records in terms of rads with a
stipulation as to the type of radiation involved.
5.10 One can examine the difficulties arising if the average
yearly dose of 5 rems for occupational exposure is increased or
decreased. Immediately, it is seen from the information in Section
II that one cannot increase this level by as much as a factor of 10
without materially increasing the possibility of biological harm,
for this is close to the level at which biological damage has been
observed (see paragraphs 2.18 and 2.19).
5.11 Fortunately, it appears that there is no necessity for set-
ting the level this high because the doses actually received are
generally much less at the present time. It also appears that
these recommended levels do not unduly restrict the beneficial use
of radiation. In this connection, it is interesting to examine the
-------
1038 LEGAL COMPILATION—RADIATION
distribution of doses received by radiation workers. Figure 5.1
shows the dose distribution for all AEG radiation workers. Each
of these persons was supposed to receive less than 12 r yearly and
not more than 5 r when averaged over a number of years. It ap-
pears that about 3 persons per 10,000 were involved in accidents,
so they received more than 12 r. Only about 3 per 1,000 received
more than 5 r and only about 1 per 100 received more than 3 r.
Thus, if there is some assurance that those receiving the high
doses in any year are not those who receive them every year, the
accumulated dose received by each worker during 50 years of
radiation employment will be considerably less than 250 r or
50 X 5r.
5.12 On the other hand, for economic and other operational
reasons, one cannot set the level too low. This is not only because
of the cost of extra radiation shielding and other radiation pro-
tection measures, but even more because of the difficulty of
radiation measurements in regions where the radiation levels vary
widely in both time and space.
MEASURABILITY OF EXTERNAL EXPOSURE
5.13 After the selection of Radiation Protection Guides, it is
necessary to examine the numbers so selected for their measur-
ability. Measurability here is used in the sense of both sample
selection and sample measurement.
5.14 The radiation worker who has a reasonable chance of re-
ceiving radiation as a result of his employment can be monitored
essentially for the entire time he is on the job. There are instru-
ments available to make measurements with acceptable precision
and accuracy at the levels recommended in the Radiation Protec-
tion Guides.
5.15 The problem of sampling the human population in the
vicinity of an operation which might expose people to radiation
may be a very simple one or a very complex one depending on the
operation and the distribution of people around the operation.
The actual measurement of 0.5 rem per year is usually a difficult
one to make. This number is near or below the accurate level
of many widely used monitoring instruments. It will take special
methods on the part of the monitoring group to measure this
number with sufficient accuracy.
[p. 28]
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-
HIS
E
GUIDELINES AND REPORTS
1039
a) (D in o
.-H OJ CD CO
o r-T c4 ^T
s
[p. 29]
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1040 LEGAL COMPILATION—RADIATION
ORGAN DOSES '
5.16 The recommendations of this staff report include (para-
graph 7.10) recommendations of organ doses to the radiation
worker which are believed to carry a biological risk not greater
than that represented by 5 rem of whole body exposure. These
organ doses may also represent a starting point for the derivation
of Radioactivity Concentration Guides for the worker.
5.17 The establishment of individual organ doses for the general
population involves additional considerations which preclude the
possibility of relating them to the Guides for the radiation worker
by a simple mathematical relationship that is applicable to all
situations. An extension of the recommendations contained in this
document in order to provide guidance in the derivation of Radio-
activity Concentration Guides for the population is recognized as
an important responsibility of the Federal Radiation Council.
The complexities are such that a detailed study is required. In
order to make our basic recommendations known as soon as pos-
sible, it was deemed advisable not to delay the release of our initial
recommendations pending the completion of our studies of this and
certain other important problems. It appears that there will be
no undue risk nor undue hardship if the Federal agencies and
departments continue their present practices concerning organ
doses for the general population during this interim period. *
SUMMARY
5.18 It appears feasible to establish a Radiation Protection
Guide for the general population with primary relationship to
background radiation levels. For radiation workers a Guide can
be established which appears to be generally practicable in its
application, and for which even pessimistic predictions of biolog-
ical damage would be so small as to warrant acceptance if any
appreciable benefit results.
5.19 It is not reasonable to establish Radiation Protection
Guides which take into account all possible combinations of cir-
cumstances. Every reasonable effort should be made to keep
exposures below any level selected. Similarly, it is obviously
appropriate to exceed the level if careful study indicates that the
probable benefits will outweigh the potential risk. Thus, the de-
gree of control effort does not depend solely on whether or not this
Guide is being exceeded. Rather, any exposure may call for some
control effort, the magnitude of which increases with the dose.
1 For one approach to this problem, see Recommendations of the International Commission on
Radiological Piotection, (Sept. 9, 1958), page 16, paiagraph 68.
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GUIDELINES AND REPORTS 1041
5.20 There are many pertinent reasons why the Radiation Pro-
tection Guide for the general population should be lower than that
for the radiation worker. Although it is feasible to monitor
essentially all exposure to radiation workers, a similar approach
to exposure of the general population is not generally feasible. As
an operational technique, where the individual whole body doses
are not known, a suitable sample of the exposed population should
be developed whose protection guide for annual whole body dose
will be 0.17 rem per capita per year. It is emphasized that this is
an operational technique which should be modified to meet special
situations.
5.21 The complexities of establishing guides applicable to radia-
tion exposure of all body organs for the population preclude their
inclusion in the staff report at this time. However, current con-
centration guides now used by the Federal agencies appear ap-
propriate on an interim basis.
[p. 30]
SECTION VI.—DERIVED GUIDES
6.1 This section is concerned with the amount of radioactive
material, deposited internally in the body or its organs ("body
burdens" and "organ burdens"), which results in a certain phys-
ical radiation dose; the amount of environmental contamination
with radioactive material which produces a given body or organ
burden (Radioactivity Concentration Guides); and accompanying
levels in the body excreta.
BODY AND ORGAN BURDENS
6.2 Calculation of the physical dose delivered to a given mass
of material as the result of homogeneous distribution of a known
quantity of radioactive material throughout a volume is rather
straight-forward, and can be made with considerable precision
and accuracy. This statement is especially valid if the volume in-
volved is in some standard geometric arrangement, such as a
sphere. Similar calculations regarding the physical dose to all or
a part of the human body as a result of radioactive material de-
posited within it will yield data which diverge from the true value
for several reasons, including the following-;
(1) Distribution of the radioactive material may be nonhomogeneous because
of selective distribution between organs or between portions of the same organ.
For example, the thyroid gland has a high degree of selective uptake for radio-
active iodine as compared to the body as a whole; various major portions of the
same bone may contain differing amounts of radium, dependent, at least in part,
upon relative growth rates.
(2) At the microscopic level there may be a significant degree of nonhomo-
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1042 LEGAL COMPILATION—RADIATION
geneity of deposition. For example, not only will the radium content of various
major portions of the bone differ, but within a single major portion different
cells or groups of cells may contain widely differing quantities of radionuclides.
Likewise, colloidal thorium oxide in the liver may concentrate almost en-
tirely in certain types of cells, leaving other cell types essentially free of
contamination.
(3) The shape of the organ or whole body may differ from any simple geo-
metric form. Few organs of the body are truly spherical, and the majority of
body organs are not true simple geometric shapes, such as cylinders, cubes, and
ellipsoids.
6.3 With highly penetrating radiation, such an energetic gamma
rays, the lack of homogeneous distribution may introduce only a
relatively small error. However, with radiations of very low pen-
etrating power such as alpha emissions, nonhomogeneity can
result in variations by several orders of magnitude (factors of
ten) among different cells in the same organ. With regard to the
shape of body organs or the whole body, calculations are most often
made on the basis of an idealized geometry; this simplification does
not introduce serious errors into the calculations. For example,
the variations introduced by considering a body organ as a sphere
or a cylinder do not introduce errors which are significant com-
pared to the lack of quantitative knowledge concerning biological
effects of irradiation.
6.4 Thus, for highly penetrating radiation the relatively
straightforward and comparatively simple calculation relating
body or organ burden to physical dose provides relatively accurate
answers. For less penetrating radiations such as beta rays, the
distribution pattern becomes more important, but, giving due re-
gard to this problem, the calculations should ordinarily not err by
orders of magnitude. With even less penetrating radiation such
as alpha particles, however, the potential errors in the calculations
are such as to make the answers clearly suspect.
6.5 As an additional complication, assessment of the biological
significance of internally deposited radioactive materials emitting
particles with high linear energy transfer, such as alphas, require
[p. 31]
the introduction of a factor for relative biological effectiveness.
Thus, the computation of the body burden of beta or gamma emit-
ting material which is biologically equivalent to a given amount of
alpha emitting material is fraught with many pitfalls and in-
accuracies.
RADIOACTIVITY CONCENTRATION GUIDES
6.6 The measurement of body burdens provides information
regarding the extent to which an individual has accumulated radio-
-------
GUIDELINES AND REPORTS 1043
active materials. However, it is not always practical to monitor
the body burdens resulting from environmental contamination
solely by the use of direct measurements on the human body, its
tissues, or excreta. Although certain supplemental information
can be obtained by monitoring the organ and body burdens of
animals, this approach also has significant practical limitations.
Furthermore, it is usually desirable to predict the significance of
environmental contamination without waiting until it has ac-
cumulated in humans or animals.
6.7 For these reasons, direct data on the levels of environmental
contamination are being collected, and it is necessary to have
guides or benchmarks against which these environmental con-
tamination levels can be evaluated. The National Committee on
Radiation Protection and Measurements and its international
counterpart have been publishing, for many years, tables of "max-
imum permissible concentrations" of radionuclides in air and in
water for radiation workers.
6.8 Our understanding of the basis used in the derivation of
these values is:
For the majority of radionuclides, the body burden which would result in a
specified average annual dose is calculated. The doses used for this purpose are
15 rems for most individual organs of the body, 30 rems when the critical organ
is the thyroid or the skin, and 5 rems when the gonads or the whole body is the
critical organ. For bone seekers, the estimation is based on the deposition of
radioactive material, the relative biological effectiveness, and a comparison of
the effective energy release in the bone with the effective energy release from a
body burden of 0.1 microgram of radium-226 plus daughters. According to
certain calculations, this bone limit may correspond to approximately 30 rems
per year. However, the difficulties inherent in estimating the physical dose to
organs from alpha emitting isotopes, together with the relatively large amount
of direct information on the biological effects of various body burdens of radium,
have led the NCRP to use this basis for its recommendations. Once the "per-
missible body burden" has been decided upon, calculations are made as to the
daily intake which, continued over a 50-year period, would not result in an ac-
cumulation greater than the permissible body or organ burden. (COMMENT:
It is to be noted that the limiting factor is a maximum annual dose rate by the
end of the period of exposure. Within this limitation there can be differences in
the total accumulated dose depending upon the time taken for the isotope to
reach an equilibrium concentration in the body. For example, with the same
maximum dose rate, the total accumulated dose with a short half-life bone-
seeker could be approximately twice the accumulated dose from a long half-life
bone-seeker.) While biological data are introduced where available, the basis
of much of these calculations is the so-called "standard man" which provides
representative constants for the many variables involved. With regard to the
determination of permissible intake by ingestion, among the variables involved
are:
(1) The fraction of the ingested material which is absorbed into the
blood from the gastro-intestinal tract. (COMMENT: Even for a given
radionuclide, this may be quite variable depending upon the individual, the
-------
1044 LEGAL COMPILATION—RADIATION
chemical form in which the radionuclide is present and its relative solu-
bility, and the influence of other materials also present in the gastro-
intestinal tract.)
(2) The fraction of material present in the blood which becomes de-
posited in the critical organ. (COMMENT: Here again, there will be
appreciable individual variations and, of course, major differences with
various isotopes.)
(3) Rate of uptake and the time of retention of the material in the
critical organ.
[p. 32]
6.9 Available biological data were utilized in the NCRP-ICRP
computations whenever available. In many cases, the available
data are extremely meager, and for certain isotopes, essentially
nonexistent. Thus, there is a rather high degree of uncertainty in
the calculation of permissible daily intakes, especially for the less
adequately studied radionuclides. Even ignoring individual var-
iability, estimates of permissible intakes of ingested radionuclides
might vary by factors of 10 to 100 if all of the errors worked in
one direction. This, however, is a rather unlikely situation and it
appears from the rather meager direct data that, for ingestion,
the estimates may be correct within a factor of less than 10.
6.10 Similar considerations are also involved for inhaled radio-
active material, except that an estimate of the fraction of inhaled
material which reaches the lungs and becomes absorbed into the
blood stream is used, instead of the fraction absorbed from the
gastro-intestinal tract for ingested material. Estimates and cal-
culations of permissible intakes for inhalation appear much less
reliable than for those for ingestion. This results primarily from
our rather poor understanding of absorption from the lungs and
such added complexities as the effect of particle size. The possible
errors with regard to inhaled radionuclides being greater than for
ingested radionuclides, it is possible that these intake values could
be incorrect by even several orders of magnitude, especially if al-
lowance is made for the existence of variations between in-
dividuals.
6.11 Once the NCRP has determined "permissible daily intake"
by ingestion or inhalation, "maximum permissible concentrations"
in air and water are derived by assuming that the total daily in-
take of water is 2.2 liters and that the water is uniformly con-
taminated; and that the total breathing rate is 2 X 107 milliliters
per 24 hours and the air is likewise uniformly contaminated.
These give values for the "168-hour week" which are then adjusted
upward by a factor of 3 for ingestion and a factor of 3 for in-
halation to allow for the shorter time exposure involved in a
40-hour week.
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GUIDELINES AND REPORTS 1045
6.12 When lower Radiation Protection Guides are selected for
the whole population as compared to the worker, this includes
allowances for differential sensitivity between children and adults.
However, in establishing Radioactivity Concentration Guides,
consideration must also be given to the possibly different ratios
of intake to uptake for adults and children. Whether this addi-
tional difference is sufficiently great to alter the final recommenda-
tion cannot be decided without thorough consideration of the spe-
cific radionuclide at hand.
6.13 It is also important to note that guides for continuous
exposure are not readily converted to guides for short-term expo-
sure by any simple mathematical relationship appropriate to all
radionuclides. It is essential that detailed study of this problem
be conducted as expeditiously and thoroughly as possible.
6.14 Taking the above factors into account, attention is being
given to the establishment of numerical values for Radiation Con-
centration Guides applicable to the general population for the
radionuclides of immediate practical importance to whole popula-
tion exposure.
DETERMINATION OF BODY BURDENS IN THE INTACT HUMAN
6.15 Because of the many complications inherent in attempts to
establish Radioactive Contamination Guides for the environment,
attempts to determine body burden in the intact human have been
made both as a control measure and as a technique for refinement
of our knowledge regarding the relationship of intake to body or
organ burdens. Historically, the quantitative determination of the
radon content of the exhaled air has been used for decades as a
technique for estimating the body burden of radium, the radio-
active parent of radon. This particular technique has proved to
be an extremely valuable one and the relationship has been sub-
stantiated by direct determination of the radium content of the
skeleton of a few individuals. There are, however, relatively few
radioactive materials which are deposited in body organs in a
solid form and which decay to radioactive gaseous daughter
products.
6.16 An additional approach has been to determine the radio-
active content of the urine and feces in order to provide data to
estimate the body or organ burden. This approach eliminates
many of the uncertainties involved in converting intake to uptake.
It does not, however, provide a direct answer as the excretion
rate of any given radioactive material will vary between individ-
[p. 33]
uals and within the same individual from time to time. An
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1046 LEGAL COMPILATION—RADIATION
important limitation in this technique arises from the fact that the
excreta will contain not only a portion of the radioactive material
which truly represents the organ burden, but also additional
amounts may be present as a result of excretion of radioactivity
which is not fixed in the tissues. Thus, measurements of excreta
are particularly unreliable at relatively short times after an ex-
posure, or during a continuing exposure. Additionally, the
amounts in the excreta will usually be only a very small fraction
of the body burden, and thus the quantities involved at levels of
interest may be so small as to require extremely sophisticated
radiochemical analytical techniques. In spite of these limitations,
the relative directness of this approach as compared to the estima-
tion of human exposure by analysis of environmental samples has
led to its practical application in certain installations. It is to be
noted, however, that the difficulties in the conduct of the proce-
dures and interpretation of the data suggest that this method is
not likely to be immediately useful for the study of problems
related to exposure of large population groups.
6.17 One other approach to the determination of body or organ
burdens is the use of "whole-body counters." This method can pro-
vide extremely useful information, but has several important
limitations:
(1) The emissions of the radionuclide under consideration must have suffi-
cient penetrating power to pass through intervening body tissues.
(2) The quantities involved must be sufficiently great to yield significant data
in a reasonable period of time.
(3) For detection of very low levels, the equipment needed and the capabili-
ties required for its operation can result in practical limitations when attempts
are made to apply this technique to large numbers of people.
SUITABILITY AND MEASURABILITY
6.18 At the present time the serious gaps in knowledge which
exist with regard to factors involved in the establishment of de-
rived standards make them unsuitable as exact standards. Oc-
casional short-term excesses should not be cause for undue concern.
Meanwhile, major effort should be expended to determine the
various unknowns, particularly those which relate intake to uptake
in the body, with greater accuracy.
6.19 It appears that techniques are available to detect and
measure, with adequate accuracy, environmental contamination
near the levels currently recommended by the NCRP at least for
several of the more important radionuclides. Such measurements
are not necessarily simple or inexpensive, but should be within the
competence of routine laboratories. However, the procedures in-
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GUIDELINES AND REPORTS 1047
volved may be sufficiently complicated that sampling on only a
representative portion of the environment is indicated.
ATMOSPHERIC CONTAMINATION IN URANIUM MINES
6.20 In addition to the current recommendations of the NCRP,
the American Standards Association (ASA) has been active in the
establishment of recommendations in this field concerning air
contamination from radon and its daughter products. It appears
that quite different approaches are used by these two groups, and
the apparent differences are not readily explainable on a simple
basis. Rather, there are differences as to whether primary em-
phasis is placed on dose calculations or on direct biological evidence
and operational considerations. These recommendations are ex-
pressed in terms of different radionuclides, so that direct numer-
ical comparison is not easily done. It is not immediately apparent
that the measurements actually taken in the mines are directly
applicable to the NCRP standard. It does appear prudent to as-
sume, however, that significant numbers of individuals are being
exposed to radiation in the mines that are in excess of the recom-
mendations of either group. It is desirable, therefore, to make
every reasonable attempt, on a continuing basis, to keep the expo-
sures as low as practical. Reduction of the contamination to the
recommended levels would be difficult and even unfeasible in some
cases.
[p. 34]
6.21 In the meantime, the exposed group is being kept under
close medical surveillance. This program should be continued,
and expanded if there appears to be any probability of securing
additional significant information. In addition, major efforts
should be made to better define the radionuclide of principal sig-
nificance to this problem.
SUMMARY
6.22 Reasonably accurate estimates can usually be made of the
amount of internally deposited radioactive material equivalent to
any given dose to a critical organ of the body. However, the estab-
lishment of guides as to the amount of material which, when taken
into the body, will yield such organ burdens is fraught with many
uncertainties. Further extension of the estimation to indicate the
equivalent amount of environmental contamination is even more
uncertain. The potential errors are greater with inhaled contami-
nation than with ingested materials. Extension to individual por-
tions of the environment further compounds the possible errors.
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1048 LEGAL COMPILATION—RADIATION
The possibility of multiple radionuclides in the same critical organ
must be considered, and appropriate allowances made to be certain
that the total dose to that organ is not excessive. At the present
time, it therefore does not seem appropriate to consider Radio-
active Concentration Guides or other derived standards as any-
thing more than guidance levels, to be applied with judgment and
discretion.
6.23 It is critical to note that no single standard is applicable to
all situations. For example, the level at which the release of radio-
activity from normal operations of a nuclear energy plant should
be restricted might be quite different from the levels at which a
food or milk supply is destroyed or discarded.
[p. 35]
SECTION VII.—SUMMARY AND RECOMMENDATIONS
7.1 To provide a Federal policy on human radiation exposure,
the Federal Radiation Council was formed in 1959 (Public Law
86-373) to "...advise the President with respect to radiation
matters, directly or indirectly affecting health, including guidance
for all Federal agencies in the formulation of radiation standards
and in the establishment and execution of programs of cooperation
with States. . . ." The present staff report is a first step in carry-
ing out this responsibility.
7.2 The scope of this staff report is limited to provide some basic
radiation protection recommendations which are required. Some
of these recommendations should be considered only of an interim
nature. Periodic review will be necessary to incorporate new in-
formation as it develops. Only peacetime uses of radiation which
affect the exposure of the civilian population are considered at this
time. A further limitation of the staff report is that it does not
consider the effects on the population arising from major nuclear
accidents. Certain of the classes of radiation sources are now
regulated by various Federal agencies. However, there are some
which are not so regulated but which should be considered when
dealing with the overall exposure of the population to radiation.
Therefore, this staff report considers exposure of the population
from all sources except those excluded above.
7.3 Only that portion of the knowledge of the biological effects
of radiation that is significant for setting radiation protection
standards is considered. Published information is summarized in
this report; details may be obtained from reading the original doc-
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GUIDELINES AND REPORTS 1049
uments. Among the items of most immediate interest to the estab-
lishment of radiation protection standards are the following:
1. Acute doses of radiation may produce immediate or delayed effects, or both.
2. As acute whole body doses increase above approximately 25 rems (units
of radiation dose), immediately observable effects increase in severity with dose,
beginning from barely detectable changes, to biological signs clearly indicating
damage, to death, at levels of a few hundred rems.
3. Delayed effects produced either by acute irradiation or by chronic irradia-
tion are similar in kind, but the ability of the body to repair radiation is usually
more effective in the case of chronic than acute irradiation.
4. The delayed effects from radiation are in general indistinguishable from
familiar pathological conditions usually present in the population.
5. Delayed effects include genetic effects (effects transmitted to succeeding
generations), increased incidence of tumors, life span shortening, and growth
and development changes.
6. The child, the infant, and the unborn infant appear to be more sensitive to
radiation than the adult.
7. The various organs of the body differ in their sensitivity to radiation.
8. Although ionizing radiation can induce genetic and somatic effects (effects
on the individual during his lifetime other than genetic effects), the evidence
at the present time is insufficient to justify precise conclusions on the nature of
the dose-effect relationship especially at low doses and dose rates. More-
over, the evidence is insufficient to prove either the hypothesis of a "damage
threshold" (a point below which no damage occurs) or the hypothesis of "no
threshold" in man at low doses.
9. If one assumes a direct linear relation between biological effect and the
amount of dose, it then becomes possible to relate very low dose to an assumed
[P. 36]
biological effect even though it is not detectable. It is generally agreed that the
effect that may actually occur will not exceed the amount predicted by this
assumption.
7.4 To clarify the most critical problem areas concerning quan-
titative relationships of the effects of irradiation on man, it is
recommended that special attention be given to the following re-
search efforts:
1. Increasing epidemiological studies on humans who have been exposed to
radiation especially in doses sufficient to offer some probability that deleterious
effects can be found.
2. Continuing studies on the mechanism of radiation damage and of inter-
action of radiation with matter at the cellular level and at the molecular level.
3. Studies designed to determine more adequately the relationship between
damage and dose at low total dose and low dose rates. Included should be more
precise information at higher levels from which the relationships at lower levels
may be inferred.
7.5 The various current sources of radiation exposure to the
U. S. population are discussed in Section III. It should be noted
that the radiation exposure to patients by practitioners of the heal-
ing arts is in the same order as natural background, when av-
eraged over the population. The average exposure to the U. S.
-------
1050 LEGAL COMPILATION—RADIATION
population from activities of the nuclear energy industry, under
current practices, is less than that from background by a sub-
stantial factor.
7.6 If the presence of a threshold for radiation damage could be
established by adequate scientific evidence, and if this threshold
were above the background level and sufficiently high to represent
a reasonable working level, it would serve as a relatively simple
basis for the establishment of radiation protection standards.
However, with the accumulation of quantitative information con-
cerning radiation effects in both animals and humans, and some
increased understanding of the mechanisms of radiation injury,
the possibility that somatic effects as well as genetic effects might
have no threshold appeared acceptable, as a conservative assump-
tion, to increasing numbers of scientists. On the basis of this con-
servative assumption, radiation protection standards must be
established by a process of balancing biological risk and the ben-
efits derived from radiation use. Such a balance cannot be made
on the basis of a precise mathematical formula but must be a
matter of informed judgment. Several approaches towards the
evaluation of the risk are discussed in Section IV. These ap-
proaches, together with the evaluation of benefits and useful ap-
plications by the agences, have been used in the formulation of the
recommendations in this staff report.
7.7 Under the working assumptions used, there can be no single
"permissible" or "acceptable" level of exposure, without regard
to the reasons for permitting the exposure. The radiation dose to
the population which is appropriate to the benefits derived will
vary widely depending upon the importance of the reason for ex-
posing the population to a radiation dose. For example, once
weapons testing in the atmosphere has taken place, the dose to be
permitted in lieu of such alternatives as depriving the population
of essential foodstuffs might also be quite different from levels
used in the planning phases. As another example, for radiation
workers, emergency situations will almost certainly arise which
make exposures in excess of those applicable to normal operations
desirable.
7.8 Also, under the assumptions used, it is noted that all ex-
posures should be kept as far below any arbitrarily selected levels
as practicable. There should not be any man-made radiation ex-
posure without the expectation of benefit resulting from such ex-
posure. Activities resulting in man-made radiation exposure
should be authorized for useful applications provided the recom-
mendations set forth in this staff report are followed. Within this
context, any numerical recommendations should be considered as
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GUIDELINES AND REPORTS
1051
guides, and the need is for a series of levels, each of which might be
appropriate to a particular action under certain circumstances.
7.9 The term "maximum permissible dose" is used by the NCRP
and ICRP for the radiation worker. However, this term is often
misunderstood. The words "maximum" and "permissible" both
have unfortunate connotations not intended by either the NCRP
or the ICRP. This report introduces the use of the term Radiation
Protection Guide (RPG). This term is denned as, the radiation
dose which should not be exceeded without careful consideration
of the reasons for doing so; every effort should be made to en-
courage the maintenance of radiation doses as far below this guide
as practicable.
[p. 37]
7.10 There can, of course, be quite different numerical values
for the Radiation Protection Guide, depending upon the circum-
stances. It seems useful, however, to recommend Guides which
appear appropriate for normal peacetime operations. It is rec-
ognized that our present knowledge does not provide a firm basis
within a factor of two or three for the selection of any particular
numerical value in preference to another value. Nevertheless, on
the basis set forth in Section V, the following Radiation Protection
Guides are recommended for normal peacetime operations:
Type of exposure Condition
Radiation worker:
(a) Whole body, head and Accumulated
trunk, active blood dose
forming organs, gonads,
or lens of eye. 13 weeks
(b) Skin of whole body and Year
thyroid 13 weeks
(c) Hands and forearms, feet Year
and ankles. 13 weeks
(d) Bone Body burden
(e) Other organs
Population 2
(a) Individual3..
(b) Average 3....
Year
13 weeks
Year
30 years
Dose J (rem)
5 times number of years
beyond age 18
3
30
10
75
25
0.1 microgram
of radium-226 or its
biological equivalent
15
5
0.5
(whole body)
5
(gonads)
ificant in
1 Minor variations here from certain other recommendations are not considered signifi
light of present uncertainties.
- See Section V for reasons why these values differ from those applicable to radiation workers.
3 See Paragraph 5.4 for applicability of these levels.
-------
1052 LEGAL COMPILATION—RADIATION
7.11 Recommendations are not made concerning- the Radiation
Protection Guides for individual organ doses to the population,
other than the gonads. Unfortunately, the complexities of estab-
lishing guides applicable to radiation exposure of all body organs
preclude their inclusion in the report at this time. However, cur-
rent protection guides used by the agencies appear appropriate on
an interim basis.
7.12 These guides are not intended to apply to radiation ex-
posure resulting from natural background or the purposeful ex-
posure of patients by practitioners of the healing arts.
7.13 The Federal agencies should apply these Radiation Pro-
tection Guides with judgment and discretion, to assure that reason-
able probability is achieved in the attainment of the desired goal
of protecting man from the undesirable effects of radiation. The
Guides may be exceeded only after the Federal agency having jur-
isdiction over the matter has carefully considered the reason for
doing so in light of the recommendations in this staff report.
7.14 This staff report also introduces the term Radioactivity
Concentration Guide (RCG) denned as: the concentration of ra-
dioactivity in the environment which is determined to result in
organ doses equal to the Radiation Protection Guide. Within this
definition, Radioactivity Concentration Guide can be established
only after the Radiation Protection Guide is decided upon. Any
given Radioactivity Concentration Guide is applicable only for the
circumstances under which use of its corresponding Radiation
Protection Guide is appropriate.
[p. 38]
7.15 As discussed in Section VI, reasonably accurate estimates
can be made of the amount of internally deposited radioactive ma-
terial resulting in any particular organ dose. However, the estab-
lishment of guides as to the amount of material which, when taken
into the body, will yield such organ doses is fraught with many
uncertainties. Further extension of the estimation to indicate the
equivalent amount of environmental contamination is even more
uncertain. The potential errors are even greater with inhaled
contamination than with ingested materials. Extension to in-
dividual portions of the environment further compounds the pos-
sible errors.
7.16 This staff report, therefore, does not contain specific nu-
merical recommendations for Radioactivity Concentration Guides.
However, concentration guides now used by the agencies appear
appropriate on an interim basis. Where appropriate radioactivity
concentration guides are not available, and where Radiation Pro-
tection Guides for specific organs are provided in this staff report,
-------
GUIDELINES AND REPORTS 1053
the latter Guides can be used by the Federal agencies as a starting
point for the derivation of radioactivity concentration guides ap-
plicable to their particular problems. The Federal Radiation
Council has also initiated action directed towards the develop-
ment of additional Guides for radiation protection.
7.17 Particular attention is directed to the possibly different
ratios of intake to uptake for adults and children. There is no
simple numerical relationship between Radioactivity Concentra-
tion Guides for the worker and for the general population, even if
such a simple relationship is adopted for Radiation Protection
Guides.
7.18 With particular relationship to the establishment of Radio-
activity Concentration Guides, the following research needs (in
addition to those listed in paragraph 7.4) are pointed out:
1. Efforts to design better and less expensive radiation monitoring instru-
ments and methods.
2. Extensive studies to determine the relationship between concentration of
radioactivity in food, air and water, and the ultimate disposition of these by
the body.
3. Studies designed to elucidate the relationship between the intake of radio-
nuclides in various chemical forms and their subsequent uptake. Presently,
many compounds of a given radionuclide are treated as though they were the
same compound.
4. Studies to elucidate the difference between children and adults in their
uptake and disposition of radioactivity and their radiation sensitivity.
[p. 39]
4.1a(l) RADIATION PROTECTION GUIDANCE FOR FEDERAL
AGENCIES (MEMORANDUM FOR THE PRESIDENT),
FEDERAL RADIATION COUNCIL
May 18,1860, 25 Fed. Reg. 4402 (1960)
MEMORANDUM FOR THE PRESIDENT
Pursuant to Executive Order 10831 and Public Law 86-373, the
Federal Radiation Council has made a study of the hazards and
use of radiation. We herewith transmit our first report to you
concerning our findings and our recommendations for the guidance
of Federal agencies in the conduct of their radiation protection
activities.
It is the statutory responsibility of the Council to "* * * advise
the President with respect to radiation matters, directly or in-
directly affecting health, including guidance for all Federal agen-
cies in the formulation of radiation standards and in the
-------
1054 LEGAL COMPILATION—RADIATION
establishment and execution of programs of cooperation with
States * * *"
Fundamentally, setting basic radiation protection standards
involves passing judgment on the extent of the possible health
hazard society is willing to accept in order to realize the known
benefits of radiation. It involves inevitably a balancing between
total health protection, which might require foregoing any activi-
ties increasing exposure to radiation, and the vigorous promotion
of the use of radiation and atomic energy in order to achieve
optimum benefits.
The Federal Radiation Council has reviewed available knowl-
edge on radiation effects and consulted with scientists within and
outside the Government. Each member has also examined the
guidance recommended in this memorandum in light of his statu-
tory responsibilities. Although the guidance does not cover all
phases of radiation protection, such as internal emitters, we find
that the guidance which we recommend that you provide for the
use of Federal agencies gives appropriate consideration to the
requirements of health protection and the beneficial uses of radia-
tion and atomic energy. Our further findings and recommenda-
tions follow.
Discussion. The fundamental problem in establishing radiation
protection guides is to allow as much of the beneficial uses of
ionizing radiation as possible while assuring that man is not
exposed to undue hazard. To get a true insight into the scope
of the problem and the impact of the decisions involved, a review
of the benefits and the hazards is necessary.
It is important in considering both the benefits and hazards of
radiation to appreciate that man has existed throughout his history
in a bath of natural radiation. This background radiation, which
varies over the earth, provides a partial basis for understanding
the effects of radiation on man and serves as an indicator of the
ranges of radiation exposures within which the human population
has developed and increased.
The benefits of ionizing radiation. Radiation properly controlled
is a boon to mankind. It has been of inestimable value in the
diagnosis and treatment of diseases. It can provide sources of
energy greater than any the world has yet had available. In
industry, it is used as a tool to measure thickness, quantity or
quality, to discover hidden flaws, to trace liquid flow, and for
other purposes. So many research uses for ionizing radiation
have been found that scientists in many diverse fields now rank
radiation with the microscope in value as a working tool.
The hazards of ionizing radiation. Ionizing radiation involves
-------
GUIDELINES AND REPORTS 1055
health hazards just as do many other useful tools. Scientific
findings concerning the biological effects of radiation of most
immediate interest to the establishment of radiation protection
standards are the following:
1. Acute doses of radiation may produce immediate or delayed
effects, or both.
2. As acute whole body doses increase above approximately 25
rems (units of radiation dose), immediately observable effects
increase in severity with dose, beginning from barely detectable
changes, to biological signs clearly indicating damage, to death
at levels of a few hundred rems.
3. Delayed effects produced either by acute irradiation or by
chronic irradiation are similar in kind, but the ability of the body
to repair radiation damage is usually more effective in the case
of chronic than acute irradiation.
4. The delayed effects from radiation are in general indistin-
guishable from familiar pathological conditions usually present
in the population.
5. Delayed effects include genetic effects (effects transmitted
to succeeding generations), increased incidence of tumors, life-
span shortening, and growth and development changes.
6. The child, the infant, and the unborn infant appear to be
more sensitive to radiation than the adult.
7. The various organs of the body differ in their sensitivity
to radiation.
8. Although ionizing radiation can induce genetic and somatic
effects (effects on the individual during his lifetime other than
genetic effects), the evidence at the present time is insufficient
to justify precise conclusions on the nature of the dose-effect rela-
tionship at low doses and dose rates. Moreover, the evidence is
insufficient to prove either the hypothesis of a "damage threshold"
(a point below which no damage occurs) or the hypothesis of "no
threshold" in man at low doses.
9. If one assumes a direct linear relation between biological
effect and the amount of dose, it then becomes possible to relate
very low dose to an assumed biological effect even though it is not
detectable. It is generally agreed that the effect that may actually
occur will not exceed the amount predicted by this assumption.
Basic biological assumptions. There are insufficient data to
provide a firm basis for evaluating radiation effects for all types
and levels of irradiation. There is particular uncertainty with
respect to the biological effects at very low doses and low-dose
rates. It is not prudent therefore to assume that there is a level
of radiation exposure below which there is absolute certainty that
-------
1056 LEGAL COMPILATION—RADIATION
no effect may occur. This consideration, in addition to the
adoption of the conservative hypothesis of a linear relation be-
tween biological effect and the amount of dose, determines our
basic approach to the formulation of radiation protection guides.
The lack of adequate scientific information makes it urgent that
additional research be undertaken and new data developed to
provide a firmer basis for evaluating biological risk. Appropriate
member agencies of the Federal Radiation Council are sponsoring
and encouraging research in these areas.
Recommendations. In view of the findings summarized above
the following recommendations are made:
It is recommended that:
1. There should not be any man-made radiation exposure with-
out the expectation of benefit resulting from such exposure. Ac-
tivities resulting in man-made radiation exposure should be
authorized for useful applications provided in recommendations
set forth herein are followed.
It is recommended that:
2. The term "Radiation Protection Guide" be adopted for Fed-
eral use. This term is defined as the radiation dose which should
not be exceeded without careful consideration of the reasons for
doing so; every effort should be made to encourage the mainte-
nance of radiation doses as far below this guide as practicable.
It is recommended that:
3. The following Radiation Protection Guides be adopted for
normal peacetime operations:
Type of exposure Condition Dose (rem)
Radiation worker:
(a) Whole body, head and trunk, active blood form- , Accumulated dose .. 5 times the number of years
ing organs, gonads, or lens of eye. j beyond age 18.
( 13 weeks 3.
(b) Skin of whole body and thyroid j Year 30.
( 13 weeks 10.
(c) Hands and forearms, feet and ankles j Year 75.
(13 weeks 25.
(d) Bone Body burden o.l microgram of radium-226
or its biological
equivalent.
(e) Other organs , Year 15.
( 13 weeks 5.
Population:
(a) Individual Year 0.5 (whole body).
(b) Average 30 year 5 (gonads).
The following points are made in relation to the Radiation
Protection Guides herein provided:
-------
GUIDELINES AND REPORTS 1057
(1) For the individual in the population, the basic Guide for
annual whole body dose is 0.5 rem. This Guide applies when the
individual whole body doses are known. As an operational tech-
nique, where the individual whole body doses are not known, a
suitable sample of the exposed population should be developed
whose protection guide for annual whole body dose will be 0.17
rem per capita per year. It is emphasized that this is an opera-
tional technique which should be modified to meet special situations.
(2) Considerations of population genetics impose a per capita
dose limitation for the gonads of 5 rems in 30 years. The opera-
tional mechanism described above for the annual individual whole
body dose of 0.5 rem is likely in the immediate future to assure
that the gonadal exposure Guide (5 rem in 30 years) is not exceeded.
(3) These Guides do not differ substantially from certain other
recommendations such as those made by the National Committee
on Radiation Protection and Measurements, the National Academy
of Sciences, and the International Commission on Radiological
Protection.
(4) The term "maximum permissible dose" is used by the
National Committee on Radiation Protection (NCRP) and the
International Commission on Radiological Protection (ICRP).
However, this term is often misunderstood. The words "maxi-
mum" and "permissible" both have unfortunate connotations not
intended by either the NCRP or the ICRP.
(5) There can be no single permissible or acceptable level of
exposure without regard to the reason for permitting the exposure.
It should be general practice to reduce exposure to radiation, and
positive effort should be carried out to fulfill the sense of these
recommendations. It is basic that exposure to radiation should
result from a real determination of its necessity.
(6) There can be different Radiation Protection Guides with
different numerical values, depending upon the circumstances. The
Guides herein recommended are appropriate for normal peacetime
operations.
(7) These Guides are not intended to apply to radiation expo-
sure resulting from natural background or the purposeful expo-
sure of patients by practitioners of the healing arts.
(8) It is recognized that our present scientific knowledge does
not provide a firm foundation within a factor of two or three for se-
lection of any particular numerical value in preference to another
value. It should be recognized that the Radiation Protection
Guides recommended in this paper are well below the level where
biological damage has been observed in humans.
It is recommended that:
-------
1058 LEGAL COMPILATION—RADIATION
4. Current protection guides used by the agencies be continued
on an interim basis for organ doses to the population.
Recommendations are not made concerning the Radiation Pro-
tection Guides on individual organ doses to the population, other
than the gonads. Unfortunately, the complexities of establishing
guides applicable to radiation exposure of all body organs pre-
clude the Council from making recommendations concerning them
at this time. However, current protection guides used by the
agencies appear appropriate on an interim basis.
It is recommended that:
5. The term "Radioactivity Concentration Guide" be adopted for
Federal use. This term is defined as the concentration of radio-
activity in the environment which is determined to result in whole
body or organ doses equal to the Radiation Protection Guide.
Within this definition, Radioactivity Concentration Guides can be
determined after the Radiation Protection Guides are decided
upon. Any given Radioactivity Concentration Guide is applicable
only for the circumstances under which the use of its corresponding
Radiation Protection Guide is appropriate.
It is recommended that:
6. The Federal agencies, as an interim measure, use radioactiv-
ity concentration guides which are consistent with the recom-
mended Radiation Protection Guides. Where no Radiation Pro-
tection Guides are provided, Federal agencies continue present
practices.
No specific numerical recommendations for Radioactivity Con-
centration Guides are provided at this time. However, concentra-
tion guides now used by the agencies appear appropriate on an
interim basis. Where appropriate radioactivity concentration
guides are not available, and where Radiation Protection Guides
for specific organs are provided herein, the latter Guides can be
used by the Federal agencies as a starting point for the derivation
of radioactivity concentration guides applicable to their particular
problems. The Federal Radiation Council has also initiated action
directed towards the development of additional Guides for radia-
tion protection.
It is recommended that:
7. The Federal agencies apply these Radiation Protection Guides
with judgment and discretion, to assure that reasonable probabil-
ity is achieved in the attainment of the desired goal of protecting
man from the undesirable effects of radiation. The Guides may
be exceeded only after the Federal agency having jurisdiction over
the matter has carefully considered the reason for doing so in light
of the recommendations in this paper.
-------
GUIDELINES AND REPORTS 1059
The Radiation Protection Guides provide a general framework
for the radiation protection requirements. It is expected that each
Federal agency, by virtue of its immediate knowledge of its oper-
ating problems, will use these Guides as a basis upon which to
develop detailed standards tailored to meet its particular require-
ments. The Council will follow the activities of the Federal agen-
cies in this area and will promote the necessary coordination to
achieve an effective Federal program.
If the foregoing recommendations are approved by you for
the guidance of Federal agencies in the conduct of their radiation
protection activities, it is further recommended that this mem-
orandum be published in the FEDERAL REGISTER.
Chairman,
ARTHUR S. FLEMMING,
Federal Radiation Council.
The recommendations numbered "1" through "7" contained in
the above memorandum are approved for the guidance of Federal
agencies, and the memorandum shall be published in the FEDERAL
REGISTER.
DWIGHT D. EISENHOWER
4.1b BACKGROUND MATERIAL FOR THE DEVELOPMENT
OF RADIATION PROTECTION STANDARDS, REPORT NO. 2,
STAFF REPORT OF THE FEDERAL RADIATION COUNCIL,
SEPTEMBER 1961
CONTENTS Page
I.—Introduction 1
II.—Thyroid Gland and Iodine-131 8
III.—Bone and Radium-226 11
IV.—Bone Marrow, Bone and Radioisotopes of Strontium 14
[p. iii]
SECTION I.—INTRODUCTION
SCOPE
1.1 Report No. 1 of the Federal Radiation Council provided a
general philosophy or radiation protection for Federal agencies.
It introduced and denned the term "Radiation Protection Guide
(RPG)." It provided numerical values for Radiation Protection
Guides for the whole body and certain organs of radiation workers
and for the whole body of individuals in the general population, as
well as an average population gonadal dose. It introduced as an
-------
1060 LEGAL COMPILATION—RADIATION
operational technique where individual whole body doses are not
known, the use of a "suitable sample" of the exposed population in
which the guide for the average exposure of the sample should be
one-third the RPG for individual members of the group. It em-
phasized that this operational technique should be modified to meet
special situations. In selecting a suitable sample, particular care
should be taken to assure that a disproportionate fraction of the
average dose is not received by the most sensitive population el-
ements. The observations, assumptions, and comments set out in
the memorandum published in the Federal Register on May 18,
1960, are equally applicable to this report.
1.2 This report is concerned with the problem of providing guid-
ance for Federal agencies in activities designed to limit exposure
of members of population groups to radiation from radioactive ma-
terials deposited in the body as a result of their occurrence in
the environment. Included are the following: (1) Radiation Pro-
tection Guides for certain organs of individuals in the general
population, as well as averages over suitable samples of exposed
groups, (2) guidance on general principles of control applicable to
all radionuclides occurring in the environment, (3) some general
principles by which Federal agencies may establish appropriate
concentration values, and (4) specific guidance in connection with
exposure of population groups to radium-226, iodine-131, stron-
tium-90, and strontium-89.
1.3 In Report No. 1, the RPG's for radiation workers apply to
individuals. Similarly, the whole body RPG for the general pop-
ulation of 0.5 rem per year applies to individual members of the
general population. As this report is concerned with radioactive
materials in the environment, individual whole body or organ doses
will usually not be known. Therefore, this report provides Radia-
tion Protection Guides not only for individuals in the general pop-
ulation, but also, using the operational technique referred to in
paragraph 1.1, for the average of suitable samples of exposed pop-
ulation groups. In the development of the guidance on intake, the
Radiation Protection Guides for averages have been used.
1.4 For radionuclides not considered in this report, Federal
agencies should use concentration values in air, water, or items of
food which are consistent with recommended Radiation Protection
Guides and the general guidance on intake.
1.5 In the future, the Council will direct attention to the devel-
opment of appropriate radiation protection guidance for those
radionuclides for which such consideration appears appropriate
or necessary. In particular, the Council will study any radio-
nuclides for which useful applications of radiation or nuclear en-
-------
GUIDELINES AND REPORTS 1061
ergy require release to the environment of significant amounts of
these nuclides. Federal agencies are urged to inform the Council
of such situations.
1.6 Radiation Protection Guide has been denned in FRC Report
No. 1 (see paragraph 1.18). For convenience, it is repeated here.
"Radiation Protection Guide (RPG) is the radiation dose
which should not be exceeded without careful consideration
of the reasons for doing so; every effort should be made to
encourage the maintenance of radiation doses as far below
this guide as practicable."
1.7 Report No. 1 also introduced and denned the term "Radio-
activity Concentration Guide." This term is not used in this re-
port. The guidance in this report is concerned with total daily
[p. 1]
intake from all sources of radionuclides rather than concentration
values in air, water, or individual items of food. Agencies, how-
ever, may find the term "Radioactivity Concentration Guide" use-
ful in some of their programs.
PREPARATION OF THE STAFF REPORT
1.8 The preparation of this report followed a pattern similar to
that for Report No. 1. The Federal Radiation Council has received
written comments from, and consulted with: (1) members of
various Federal agencies responsible for the administration of ra-
diation protection programs, (2) governmental and non-govern-
mental scientists in many related disciplines, and (3) other
individuals and groups who are interested in the subject.
1.9 In developing the recommendations given in this report, the
staff of the Council considered the extensive studies made by the
National Committee on Radiation Protection and Measurements
(NCRP) and the International Commission on Radiological Pro-
tection (ICRP) of the behavior and effects of the radionuclides
under discussion. The Council staff consulted scientists from the
many disciplines involved in the studies such as physicians, radio-
biologists, health physicists, radiochemists, and physicists. Many
of the scientists consulted were, or had been, affiliated with NCRP,
ICRP, the National Academy of Sciences (NAS), the American
Standards Association (ASA), and other scientific groups. The
staff also studied available literature and publications of the above
groups as well as those of the Medical Research Council and the
Agricultural Research Council of the United Kingdom and the
United Nations Scientific Committee on the Effects of Atomic
Radiation. In some consultations the Council staff had the op-
portunity to review current unpublished biological data.
-------
1062 LEGAL COMPILATION—RADIATION
1.10 In order to consider as completely as possible the many
factors involved in establishing radiation protection standards for
the general population, the Council solicited comments from in-
terested organizations and individuals. For this purpose, the
Council prepared and transmitted widely a paper stating major
policy issues involved in the development of radiation protection
guidance in connection with the radionuclides considered in this
report. Among these policy issues is the question as to the ap-
propriateness of specific radiation protection standards from the
point of view of their social and economic impact. Questions of
this sort do not lend themselves to exact quantitative treatment.
They are matters of judgment on which the best available infor-
mation is brought to bear.
RADIATION PROTECTION GUIDES
1.11 It has been emphasized in Report No. 1 of the Federal
Radiation Council that the establishment of radiation protection
standards involves a balancing of the benefits to be derived from
the controlled use of radiation and atomic energy against the risk
of radiation exposure. This principle is based upon the position
adopted by the Federal Radiation Council that any radiation ex-
posure of the population involves some risk; the magnitude of
which increases with the exposure. As stated in "Radiation Pro-
tection Guidance for Federal Agencies," approved by the Pres-
ident, May 18, 1960, "There should not be any man-made radiation
exposure without the expectation of benefit resulting from such
exposure." In recommending use of the term, "Radiation Pro-
tection Guide" it was stated that "This term is defined as the ra-
diation dose which should not be exceeded without careful con-
sideration of the reasons for doing so; every effort should be made
to encourage the maintenance of radiation doses as far below this
guide as practicable." Consistent with these principles, no ex-
posure to radiation should be permitted unless it satisfies two
criteria:
(1) The various benefits to be expected as a result of the exposure, as eval-
uated by the appropriate responsible group, must outweigh the potential hazard
or risk, and
(2) the reasons for accepting or permitting a particular level of exposure
rather than reducing the exposure to a lower level must outweigh the decrease
in risk to be expected from reducing the exposure.
1.12 In view of the considerations discussed above, ideally, an
individual radiation protection guide should be developed for each
activity or set of circumstances involving exposure to radiation.
Recognizing the impracticability of establishing an individual
-------
GUIDELINES AND REPORTS 1063
guide for each application, the Council, in its Report No. 1, pointed
out the need for a compromise between this ideal and the applica-
[p. 2]
tion of a single guide to widely differing sets of conditions. The
following is taken from the Council's recommendations approved
by the President:
"There can be no single permissible or acceptable level of exposure without re-
gard to the reasons for permitting the exposure ... It is basic that exposure
to radiation should result from a real determination of its necessity.
There can be different Radiation Protection Guides with different numerical
values, depending upon the circumstances. The guides recommended herein
are appropriate for normal peacetime operations."
1.13 On the basis of extensive consultation, the Council has rec-
ommended to the President a set of Radiation Protection Guides
which represent a generalized balance between the considerations
discussed above. Despite wide differences in the assignment of
relative values to the various factors involved, the Council be-
lieves that the overall benefits from useful activities involving ex-
posures to radiation at levels within those specified in these guides
will outweigh the risks associated with such exposures. There is
also sufficient experience in limiting radiation exposures to levels
similar to these to demonstrate the general feasibility, with few
exceptions, of operating at or below the levels specified in these
guides in normal peacetime operations.
1.14 The Federal agencies, when applying these Radiation
Protection Guides should recognize that they represent generalized
and not specific guidance. Because the reasons for accepting or
permitting exposure to radiation vary so widely from one situation
to another, the guides cannot represent the most appropriate ones
for some situations without being inappropriately high or low for
others. Each agency should determine, in any specific application,
the extent to which the generalized guides apply in the specific
situation. For example, certain applications may be able to be
conducted at a guide specifying a lower dose than the RPG rec-
ommended by the Council. On the other hand, some applications
which are not practicable under existing guides and for which the
needs are very great may require a guide specifying a higher dose.
The possibility of certain situations, such as accidents, may require
the development of guides to be used when an agency considers
such drastic actions as exclusion of persons from a specified area,
evacuation, or condemnation of supplies of food.
1.15 "Radiation Protection Guidance for Federal Agencies"
published in the Federal Register May 18, 1960, recognized that in
certain instances the balance of benefit versus risk might neces-
-------
1064 LEGAL COMPILATION—RADIATION
sitate an RPG higher than specified for normal peacetime opera-
tions. This was expressed in the following language:
"The guides may be exceeded only after the Federal agency having jurisdiction
over the matter has carefully considered the reason for doing so in light of the
recommendations in this paper."
Arrangements have been made for the Council to follow the ac-
tivities of the Federal agencies in this area and to promote the
necessary coordination to achieve an effective Federal program.
These have been described in a memorandum from the Chairman
of the Council to the President, made public on October 13, 1960.
CONTROL OF ENVIRONMENTAL RADIOACTIVITY
1.16 The objective of the control of population exposure from
radionuclides occurring in the environment is to assure that ap-
propriate RPG's are not exceeded. This control is accomplished
in general either by restrictions on the entry of radioactive mate-
rials into the environment or through measures designed to limit
the intake of such materials by members of the population. The
most direct means of evaluating the effectiveness of control
measures is the determination of the amount of radioactive mate-
rial in the bodies of the members of exposed population groups.
Although the determination of such body burdens may at times be
indicated, in routine practice potential exposures will generally be
assessed on the basis of either one or a combination of two general
approaches: (1) calculations based upon known amounts of radio-
active material released to the environment, and assumptions as to
the fraction of this material reaching exposed population groups,
or (2) environmental measurements of the amount of radioactive
material in various environmental media.
[p. 3]
1.17 Both of these general approaches involve the calculation or
determination of actual or potential concentrations of radioactive
material in air, water, or food. As stated above, controls should
be based upon an evaluation of population exposure with respect
to the RPG. For this purpose, the average total daily intake of
radioactive materials by exposed population groups, averaged over
periods of the order of a year, constitutes an appropriate criterion.
1.18 There is for any radioactive material a daily intake which
is calculated to result, under specified conditions, in whole body or
organ doses equal to a Radiation Protection Guide. The resulting
value represents either the continuous or the average daily intake
which would meet an RPG stated in terms of an annual dose. It
is evident that the daily intake of radioactive material might
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GUIDELINES AND REPORTS 1065
fluctuate very widely around the average and still result in an
annual dose which would not exceed the associated RPG.
1.19 The control of the intake of radioactive materials from the
environment can involve many different actions. The character
and import of these actions vary widely from those which entail
little interference with usual activities, such as monitoring and
surveillance, to those which involve a major disruption, such as
condemnation of food supplies. Some control actions would re-
quire prolonged lead times before becoming effective, e.g., major
changes in water supplies. For these reasons, control programs
developed by the agencies should be based upon appropriate actions
taken at different levels of intake. In order to provide guidance to
the agencies in developing appropriate programs, this report
describes a graded approach for the radionuclides considered, in-
volving three ranges of transient rates of daily intake applicable
to different degrees or kinds of action.
1.20 The objective of the graded scale of actions is to limit in-
take of radioactive materials so that specified RPG's will not be
exceeded. Daily intakes varying within the total extent of all
three ranges of intake might result in annual doses not exceeding
a single RPG. However, in instances in which the daily intake is
fluctuating above the average which would meet the RPG, it may
not be possible to be assured that this will be the case. The ac-
tions outlined below would be appropriate, not only when intakes
are fluctuating so as not to exceed a given RPG, but also in those
situations in which valid reasons exist for the responsible agency
to permit the possibility of doses which would exceed the RPG.
1.21 A suggested graded system of actions is outlined below.
For each of the three ranges of transient rates of daily intake,
specific values for which are given in the sections devoted to the
specific radionuclides, the general type of action appropriate for
the range is outlined.
RANGE I
Intakes falling into this range would not under normal cond'
tions be expected to result in any appreciable number of indi"1
uals in the population reaching a large fraction of the T"
Therefore, if calculations based upon a knowledge of the sou-
release of radioactive materials to the environment indie
intakes of the population are in this range, the only r
quired is surveillance adequate to provide reasonable cr
of calculations.
-------
1066 LEGAL COMPILATION—RADIATION
RANGE II
Intakes falling into this range would be expected to result in
average exposures to population groups not exceeding the RPG.
Therefore such intakes call for active surveillance and routine
control.
SURVEILLANCE
Surveillance must be adequate to provide reasonable assurance
that efforts being made to limit the release of radioactive materials
to the environment are effective. Surveillance must be adequate
to provide estimates of the probable variation in average daily in-
take in time and location. Detection of sharply rising trends is
very important. In some cases, because of the complexities of the
environment, surveillance data may have to be sufficiently re-
liable to be used as a rough check on whether radioactive materials
in the environment are behaving as expected. Not only the radio-
active material in question, but also the environment must be
[p. 4]
studied. Appropriate efforts might be made to obtain measure-
ments in man as well as to study physical, chemical, and metabolic
factors affecting uptake. Appropriate consideration should be
given to other independent sources of exposure to the body (the
same organs or different ones) to avoid exceeding RPG's.
CONTROL
Routine control of useful applications of radiation and atomic
energy should be such that expected average exposures of suitable
samples of an exposed population group will not exceed the upper
value of Range II. The sample should be taken with due regard
for the most sensitive population elements. Control actions for
intakes in Range II would give primary emphasis to three things:
(1) assuring by actions primarily directed at any trend sharply
upward that average levels do not rise above Range II, (2) assur-
ing by actions primarily directed either at specific causes of the
environmental exposure levels encountered or at the environment
that a limit is placed on any tendencies of specific population seg-
ments to rise above the RPG, and (3) reducing the levels of ex-
posure to segments of the population furthest above the average or
tending to exceed Range II.
RANGE III
Intakes within this range would be presumed to result in ex-
sures exceeding the RPG if continued for a sufficient period of
-------
GUIDELINES AND REPORTS 1069
combinations. Consequently, concentration values applying to the
different sources of intake must take into account the relative con-
tribution of each source to total intake. Even in those situations
where food is the only source of intake of radioactive material,
widely varying concentration values applying to different items in
the diet may be appropriate. For example, in the case of intakes in
Range III the necessity may arise for removal of a particular ra-
dionuclide from certain major contributors in the diet, or even
elimination of certain dietary items containing high concentra-
tions of the nuclide. The following are some of the considerations
which may be involved in the determination of specific levels at
which action such as the condemnation of certain food supplies
would take place:
(1) Relative proportion of the total diet by weight represented by the item
in question.
(2) The importance of the particular item in nutrition and the availability
of substitutes having the same nutritional properties, or perhaps stockpiles of
uncontaminated food.
(3) The availability of other possible control methods such as the removal
of the radioactive material from the particular dietary item without affecting
its quality.
(4) The half-life of the radioactive material.
(5) Other internal or external sources of radiation exposure to the same
organ.
(6) Relative contribution of other dietary items to the total daily intake of
the nuclide.
(7) Physical, chemical, and other factors affecting the relationship between
intake and uptake of the nuclide.
(8) The time and effort required to effect corrective action.
[p. 6]
In this connection, it is important to emphasize a point made in paragraph 1.18
in connection with guidance on intake. The agencies should bear in mind in
establishing concentration values that it is possible to have wide fluctuations
in daily intake which might still result in an annual average dose within the
RPG. It can be readily seen that, since fluctuations in concentration guides
can occur within a given intake value, even wider fluctuations can occur in
concentrations in various foods and still result in an annual average dose that
does not exceed the associated RPG. In any specific instance the greater the
variation in concentrations, the more difficult it will be to estimate average
intakes.
1.28 Because of the wide difference possible in concentration
values applying to different environmental media and depending
upon specified circumstances, the Federal Radiation Council has
not made any specific recommendations on such values. The re-
sponsible Federal agencies should develop specific concentration
values to apply to appropriate control actions as part of their
operating criteria. The Federal Radiation Council will follow de-
-------
1070 LEGAL COMPILATION—EADIATION
velopments in this area and will promote the necessary coordina-
tion to achieve an effective Federal program.
[p. 7]
SECTION II.—THE THYROID GLAND AND IODINE-ISl
INTRODUCTION
2.1 This section is concerned with the development of an RPG
for the thyroid gland and guidance in connection with exposure of
the general population to radioactive iodine. Currently, the major
concern is environmental contamination resulting from fallout
from the explosion of nuclear devices and the release of radioiodine
during the use and processing of fuel for reactors. Fission prod-
ucts so formed may contain iodine-131, -132, -133, -134, and -135.
The dose rate from the shorter-lived radionuclides (iodine-132,
-133, -134, and -135 with half-lives ranging from approximately
53 minutes to 21 hours) will decrease rapidly with time in com-
parison with iodine-131 (half-life approximately 8 days). Conse-
quently, guidance on intake of iodine-131 only is considered in this
section. However, when the shorter-lived iodine nuclides are pres-
ent and contribute significantly to the radiation dose received, they
should be taken into account in accordance with the principles for
summation of dose.
2.2 Like the naturally occurring stable isotope of iodine, iodine-
131 when ingested or inhaled concentrates in the thyroid gland.
Thus the thyroid gland receives a far larger radiation dose from
iodine-131 than any other organ in the body. Radiation protection
guidance to be used in connection with iodine-131, therefore, in-
volves the determination of RPG's for the thyroid gland.
RPG FOR THE THYROID GLAND
2.3 Report No. 1 specifies a Radiation Protection Guide for the
thyroid gland of radiation workers of 30 rem per year. It specifies
an annual whole body dose to individuals in the general population
of 0.5 rem. The whole body guide is a factor of 10 below that
specified for radiation workers. If one were to assume that the
thyroid gland of individuals in the general population is no more
sensitive when compared with the whole body than is the case in
radiation workers, it might, from the point of view of the risk
factor, be reasonable to use a value of 3 rem per year as an RPG
for the thyroid of individuals in the general population.
2.4 This, however, may not be the case. Evidence is summar-
ized below which has led the Council to the conclusion that in the
-------
GUIDELINES AND REPORTS 1071
development of RPG's for the thyroid gland it is necessary to take
the position that a child's thyroid gland, relative to other organs
of the child, is more sensitive to the carcinogenic effect of radiation
than the adult thyroid gland compared to other organs of the
adult. In the development of guidance on intake there is an ad-
ditional factor which must be considered, i.e., the ratio between
size of thyroid and intake of radioiodine in children is different
from the ratio in adults.
2.5 In Report No. 1 (paragraph 2.19) it is noted that the child's
thyroid is more sensitive to the carcinogenic effects of radiation
than the adult thyroid. This conclusion is based upon several
studies in recent years of the occurrence of thyroid carcinoma in
children who had previously received therapeutic x-irradiation in
the neck region for enlarged thymus or for other benign head and
neck conditions. The incidence of thyroid carcinoma in these
children was significantly higher than in control groups who had
not been previously irradiated.
2.6 In these studies cancer of the thyroid was observed in chil-
dren after exposures as low as approximately 150 rem. Similar
effects have been observed in adults only at much higher dosages.
Although these data do not provide a quantitative relationship,
they do indicate that the child's thyroid is more sensitive to the
carcinogenic effects of radiation than is that of the adult.
2.7 The RPG for the thyroid gland of radiation workers of 30
rem per year is twice the dose specified for other organs. This
difference is based on two factors: (1) the evidence that the thy-
roid gland in adults is a particularly radioresistant organ, and (2)
the needs for exposure of radiation workers to radioactive iodine
[p. 8]
in useful applications of radiation and atomic energy. If it were
not for these considerations, no individual treatment would have
been given the thyroid gland of radiation workers and it would
have fallen into the category of other organs with and RPG of 15
rem per year.
2.8 From the point of view of the biological risk, therefore, the
RPG for the thyroid of individuals in the general population, in-
cluding children, should be less than 1/10 of 30 rem per year. On
the other hand, it is logical to assume that the risk associated with
a given radiation dose to the child's thyroid gland must be less than
that associated with the same dose to his whole body. Thus the
RPG for the thyroid of individuals in a population group could be
higher than the 0.5 rem per year whole body dose without result-
ing in a greater biological risk.
2.9 The Council has reviewed data and studied atomic energy
-------
1072 LEGAL COMPILATION—RADIATION
operations involving exposure of the thyroid gland of members of
the general population. As noted in paragraph 2.1, such opera-
tions usually involve iodine-131. It finds that in general these
operations can be conducted without undue difficulty in such a man-
ner that the dose to the thyroid of individuals in the general popu-
lation will not exceed 1.5 rem per year. It has been stated above
that, since in the situation of environmental contamination individ-
ual doses are not usually known, this report will specify both in-
dividual doses and average doses to population groups. Therefore,
the Council recommends RPG's for the thyroid gland of 1.5 rem
per year for individuals and 0.5 rem per year to be applied to the
average of suitable samples of an exposed group in the general
population as representing a reasonable balance between biological
risk and benefit to be derived from useful applications of radiation
and atomic energy. If specific applications should be contemplated
which cannot be conducted without exceeding the dose specified in
the RPG, an individual assessment of benefit and risk must be
made by the responsible agency in accordance with the principles
previously outlined by the Council.
GUIDANCE ON INTAKE OF IODINE-131
2.10 As a step in the development of guidance on intake of
iodine-131 it is necessary to determine the average daily intake
which would meet the RPG for averages in the general population.
Among the factors to be considered are: (1) the weight of the
thyroid gland, (2) the percent of the iodine intake which reaches
the gland, and (3) the average retention time.
2.11 There is wide variation from one individual to another in
the percent of an ingested or inhaled quantity of iodine-131 which
appears in the thyroid gland. This percentage uptake is dependent
upon such factors as the amount of stable iodine in the diet and the
physiological state of the thyroid gland. In point of fact, certain
pathological conditions in humans are manifest by an increase or
decrease in the ability of the thyroid gland to concentrate iodine.
A review of the data in the United States indicates that the nor-
mally functioning thyroid gland concentrates at 24 hours on the
average approximately 30% of the initial quantity of iodine-131
taken into the body. The data also indicate that, while, as stated
above, there is wide variation from individual to individual, there
is no significant difference in the average between children and
adults.
2.12 There is some evidence that suggests that iodine is metab-
olized more rapidly in the child than in the adult. This suggests
the possibility of a somewhat shorter biological half-life. How-
-------
GUIDELINES AND REPORTS 1073
ever, adequate information concerning the effective half-life of
iodine-131 in younger children is not presently available. It is
assumed, therefore that an effective half-life of 7.6 days is ap-
plicable for all age groups.
2.13 The average mass of the thyroid gland in adults is gen-
erally taken to be 20 grams. The mass of the gland in the child is,
of course, less and depends upon the specific age. Since, as dis-
cussed above under the consideration of the RPG, the child is taken
as the limiting case, the weight of the child's thyroid is considered
as the limiting factor in the determination of guidance on intake.
In calculating the average daily intake which would meet the RPG,
the mass of the thyroid gland is taken as 2 grams. The resulting
guidance on intake should, theoretically, be applied only to children
and is subject to adjustment upward when applied only to adults.
In many practical situations this adjustment will not be feasible.
However, when agencies develop appropriate concentration values
to refer to specific modes of intake (as between inhalation and
[P. 9]
ingestion) or to different dietary elements, this consideration
should be kept in mind.
2.14 Using the known factors and the assumptions enumerated
above, it can be calculated that an average daily intake of 80 mi-
cromicrocuries of iodine-131 per day would meet the RPG for the
thyroid for averages of suitable samples of an exposed population
group of 0.5 rem per year. As stated in Section I, it is appropriate
to specify three ranges of transient rates of daily intake in order
to provide guidance for the Federal agencies in the establishment
of operating criteria. For this purpose, the value of 80 micro-
microcuries per day has been rounded off to 100 micromicrocuries
per day as being more in keeping with the precision of the data.
Therefore, the following guidance on intake of iodine-131 to be
applied to suitable samples of an exposed population group is
recommended:
Range I 0 to 10 micromicrocuries per day
Range II 10 to 100 micromicrocuries per day
Range III 100 to 1,000 micromicrocuries per day
[p. 10]
SECTION III.—BONE AND RADiuM-226
INTRODUCTION
3.1 Human experience with comparatively large quantities of
radium in the skeleton was discussed in Report No. 1 (particularly
-------
1074 LEGAL COMPILATION—RADIATION
pages 13-15) and the general practice of establishing radiation
protection guides for occupational exposure to various radio-
nuclides in the skeleton by relating them to radium-226 was en-
dorsed. For this purpose, 0.1 microgram of radium-226 in the
skeleton was adopted as a Radiation Protection Guide for radiation
workers. This value has been in general use since 1941. The
discussion in this section is concerned with the development of an
appropriate Radiation Protection Guide for bone and of corre-
sponding guidance on daily intake for control of exposures of the
general population to radium-226.
3.2 The critical organ for radium in the body is the skeleton. It
is assumed in this section that, except for radiation from natural
sources other than radium and from medical x-rays, the total ra-
diation dose to the skeleton is from radium-226 and its radioactive
decay products. If other sources of radiation contribute signif-
icantly to the radiation dose to the skeleton, it is expected that they
will be taken into account.
CONSIDERATIONS IN THE DEVELOPMENT OP RPG'S
3.3 In the consideration of the risk side of the risk-benefit bal-
ance in the development of RPG's, Report No. 1 indicated several
approaches to aid in the evaluation of the risk. Comparisons with
occupational exposure guides and with exposures from natural
background were discussed. Although neither provides a quan-
titative basis for the determination of population RPG's, each is
useful. This is particularly true in the case of radium-226 because
some data are available on both occupational and whole population
environmental exposure.
3.4 The Radiation Protection Guide recommended by the Coun-
cil for the whole body of individuals in the general population is a
factor of 10 below the whole body guide for radiation workers.
There are certain considerations, however, which indicate that the
application of the same factor to the RPG for occupational ex-
posure to radium-226 to obtain population RPG's may not provide
the same degree of protection as in the case of the whole body.
Some of these considerations are the following:
(1) The skeletal content required to give a particular radiation dose to the
bone of a child is less than for the adult. Fortunately (from the point of view
of simplicity of treatment of the problem), available data suggest that in an
environment in which the average concentration of radium in the total diet,
including water, is constant, concentrations of radium-226 in the skeletons of
humans who have lived their entire lives in the environment are found to be
relatively independent of age.
(2) The distribution of radium-226 in the skeleton of an individual who has
lived his entire life in an environment constant with respect to small quantities
-------
GUIDELINES AND REPORTS 1075
of radium in his diet will be much more uniform than that of radium deposited
in the skeleton as the result of occupational exposure. How the degree of
hazard from radium in the skeleton might depend upon nonuniformity of dis-
tribution is not known.
(3) The radiation dose to the bone from radium deposited in the skeleton
under constant environmental conditions is relatively constant throughout life.
On the other hand, the dose resulting from deposition under controlled occupa-
tional exposure increases with length of exposure. Constant environmental
exposure, therefore, results in a larger lifetime dose per unit quantity of ra-
dium-226 in the skeleton than occupational exposure in which the specified
quantity is assumed to be reached only near the end of life. Furthermore, be-
cause of the long latent periods characteristic of carcinogenesis at low dose
[p. 11]
levels, it appears reasonable to assume that the earlier in life the radiation dose
from radium is received the more likely the individual will live until any car-
cinogenic effect can become manifest.
3.5 Turning to the second approach, that of comparing the
radiation doses to the skeleton from radium-226 with radiation
doses normally received from all natural sources of radiation, it is
immediately apparent that bases for comparisons are, at best, un-
certain. In physical units of radiation dose (e.g., rads) the dose
to the skeleton from all natural sources of radiation averages be-
tween 0.1 and 0.15 rads per year. The quantities of radium-226 in
the adult skeleton which, with its radioactive decay products, are
required to give corresponding physical doses range from about
0.003 to 0.005 micrograms. There is insufficient information on
the relative biological effectiveness of the radiation from radium
to attempt a realistic conversion of this dose in rads to the skeleton
from radium and its decay products into rems.
3.6 Because of the uncertainties involved in comparing radia-
tion from radium with total radiation to the skeleton from natural
sources, it is useful to consider the natural occurrence of radium in
the skeleton. In most areas of the United States, the radium con-
tent of the adult human skeleton is found to range from about
0.0001 microgram of radium-226 to some two or three times this
amount. In such areas, the radium content of drinking water is
generally so low that the skeletal content is believed to be almost
entirely due to the occurrence of sufficient radium-226 in food to
result in a daily intake of from 1 to 2 micrograms. In some areas,
however, concentrations of radium-226 in drinking water are
sufficiently high to result in much larger daily intakes and corre-
spondingly higher amounts in the skeleton. There are communi-
ties in which unusually high radium concentrations in supplies of
drinking water result in adult skeletal levels which range upward
to amounts of the order of 0.001 microgram. A program is under-
way to determine whether any biological effects of such amounts
-------
1076 LEGAL COMPILATION—RADIATION
of radium can be detected by epidemiological studies with methods
currently available. However, it is expected that a number of
years will be required to reach any useful conclusions.
3.7 These approaches give two reference points for use in com-
parison of biological risk with reasons for acceptance of risk. In
the case of radium, reasons for acceptance of risk involve con-
sideration of the difficulty of meeting possible RPG's and the im-
pact of this difficulty on industry and the community. Before this
comparison can be made it is necessary to consider the relation-
ship between environmental levels and body content of radium
since this relationship vitally affects the difficulty of meeting any
RPG.
3.8 The data which are most relevant to the determination of
the relationship between environmental levels and body content
are the observations of the relationships between concentrations of
radium-226 in community water supplies and corresponding quan-
tities in the skeleton of persons using the water. Estimates of
average concentrations in normal United States diets and corre-
sponding average skeletal contents, while less firmly supported, are
reasonably consistent with these observations. These data in-
dicate that on the average the concentration of radium-226 in the
skeleton of individuals of any age does not exceed a value corre-
sponding to a total quantity in the adult skeleton of about fifty
times the daily intake.
3.9 The Council has considered operations involving the release
of radium-226 to the environment. These can be conducted, in
the opinion of the Council, without undue difficulty in such a man-
ner that average daily intake of radium-226 in an exposed popula-
tion group will not exceed 20 micromicrograms. The Council has
also reviewed available data on radium-226 concentrations in pub-
lic water supplies in the United States. The overwhelming major-
ity of the population consumes water from supplies corresponding
to daily intakes of radium-226 well below this level. In those situa-
tions where this may not be the case, the extremely small risk as-
sociated with intakes above this level should be considered by the
appropriate authorities in light of difficulties which may be as-
sociated with any modifications in the water supply.
3.10 In view of the above considerations, the Council recom-
mends as an alternate RPG for bone for individuals in the general
population a skeletal concentration of radium-226 corresponding
to 0.003 microgram in the adult skeleton. The RPG to be applied
to the average of suitable samples of an exposed population group
is a skeletal concentration of radium-226 corresponding to 0.001
microgram in the adult skeleton. These values are considered by
-------
GUIDELINES AND REPORTS 1077
the Council to represent an appropriate balance between biological
risk and reasons for acceptance of risk.
[p. 12]
GUIDANCE ON INTAKE
3.11 The relationship between environmental levels and body
content referred to in paragraph 3.8 indicates that an average
daily intake of 20 micromicrograms of radium-226 corresponds to
the RPG for suitable samples of exposed population groups.
Therefore, the Council recommends the following guidance on
transient rates of daily intake of radium-226 to be applied to the
average of suitable samples of an exposed population group:
Range I 0 to 2 micromicrograms per day
Range II 2 to 20 micromicrograms per day
Range III 20 to 200 micromicrograms per day
It is important to emphasize that the risk associated with this
intake guidance is, in the opinion of the Council, much lower than
has generally been considered. The skeletal content associated
with a daily intake of 20 micromicrograms is about an order of
magnitude lower than that which would be implied by extrapola-
tion from current occupational standards for radium. The Council
considers, however, that the data from the environmental studies,
though limited, represent a more valid basis for derivation of the
relationship between continuous exposure and body content.
[p. 13]
SECTION IV.—BONE MARROW, BONE AND RADIOISOTOPES OF
STRONTIUM
INTRODUCTION
4.1 In this section, RPG's for bone marrow and bone and guid-
ance for the protection of individuals in the general population
against excessive exposure to radioisotopes of strontium are de-
veloped. The chemical and physical characteristics are such that,
for this purpose, our principal interest is in the irradiation of bone
and bone marrow as the result of deposition of strontium-90 and
strontium-89 in the skeleton. Because such deposition results
from the occurrence of the radioisotopes in ingested food and
water and in inhaled air, protection is achieved by limiting average
concentrations in food, water, and air used by humans. Thus,
while the hazard to the individual results from radiation emitted
over long periods of time by material actually in his skeleton, for
purposes of control it is necessary to specify guidance on intake
of the isotopes which will not result in excessive irradiation of
-------
1078 LEGAL COMPILATION—RADIATION
body tissues. In applying such guidance to actual environmental
situations, it is necessary to convert intake values to concentration
values applicable to specific items in the total diet (both food and
water) and in inhaled air according to the general principles in
Section I.
DERIVATION OF RPG'S FOR BONE MARROW AND BONE
4.2 Report No. 1 recommended an RPG for the whole body of
individuals in the general population of 0.5 rem per year as rep-
resenting an appropriate balance between the requirements of
health protection and of the beneficial uses of radiation and atomic
energy. Basic to the considerations involved in a guide for whole
body dose were the factors associated with exposure of bone mar-
row. Thus RPG's for the bone marrow of 0.5 rem per year for
individuals in the general population and 0.17 rem per year as an
average to be applied to suitable samples of an exposed population
group are considered by the Council to represent a similarly ap-
propriate balance of benefit and risk.
4.3 Experience indicates that bone is relatively insensitive to X
and gamma radiation when compared with bone marrow. Groups
exposed to X and gamma radiation in which a higher than normal
incidence of leukemia has been observed have not shown corre-
sponding increases in bone tumors. Although these data do not
provide a quantitative basis for relating the sensitivity of bone
and bone marrow they do indicate that from the point of view of
the risk it is reasonable to permit a larger dose to bone than to
bone marrow.
4.4 In the case of strontium-90, the dose rate to bone from a
given skeletal content is three times the average dose rate to bone
marrow. Other beta emitters of similar distribution in bone and
comparable energy would yield similar factors. The Council con-
siders that Radiation Protection Guides for the bone of 1.5 rem
per year for individuals in the general population and 0.5 rem per
year as an average to be applied to suitable samples of an exposed
population group represent an appropriate balance between the
requirements of health protection and of the beneficial uses of ra-
diation and atomic energy.
THE DEVELOPMENT OF GUIDANCE ON INTAKE OF STRONTIUM-89 AND
STRONTIUM-90
4.5 The considerations involved in the development of guidance
on intake of strontium-89 and strontium-90 are summarized in the
following paragraphs. The guidance is applicable only under the
-------
GUIDELINES AND REPORTS 1079
conditions specified in their derivation, i.e. continuous exposure to
radioactive strontium in food, water, and air throughout the life-
times of the individuals involved and tinder normal peacetime op-
erations. The guidance is based on the assumption that the
exposure source it covers is the only source of exposure of the
skeleton to radiation other than natural background and medical
and dental exposures. Where actual exposure involves both stron-
tium-89 and strontium-90, or where the skeleton is also exposed to
significant amounts of radiation from other sources, such as
[P. 14]
barium-140 or abnormal quantities of radium-226, it is expected
that these will be taken into account. Likewise, where there is
significant intake through both ingestion and inhalation, it is ex-
pected that the total deposition in the skeleton will be considered.
BIOLOGICAL EFFECTS
4.6 No effects in humans attributable to the ingestion or inhala-
tion of radioactive strontium have been observed from the levels
of radioactive strontium which have occurred in the environment
nor does it appear from our present knowledge that it would be
possible to observe any. Consequently, evaluation of the hazard
to humans is primarily dependent upon extrapolation and dose
interpolation from the effects on experimental animals exposed to
far greater quantities of radioactive strontium, or from the effects
of other sources of radiation on humans.
4.7 Experimental animals given large doses of radioactive
strontium have developed osteogenic sarcomas, and it might be
expected that this would occur in a human group under similar
circumstances.
4.8 Some small laboratory animals have developed leukemia fol-
lowing large injected doses of radioactive strontium, presumably
from irradiation of the bone marrow, although the causative re-
lationship is not clear. Extrapolating animal experience to hu-
mans is very uncertain. Data obtained as a result of exposure of
humans to external radiation indicate that at levels of exposure
much higher than those under consideration here, the bone marrow
is significantly more radiosensitive than the bone.
METABOLIC FACTORS
4.9 Ingested strontium is concentrated in the mineral skeleton,
as is calcium and several other alkaline earth elements. Under
equilibrium conditions, essentially all strontium in the body is in
the skeleton. The mineral skeleton appears during intra-uterine
-------
1080 LEGAL COMPILATION—RADIATION
life, and increase in mass until about age twenty years. Another
process of bone metabolism is the continuous replacement of the
mineral portion at a low rate on a microscopic scale throughout
life. Thus, there is a continuous exchange of mineral elements
between the environment and the blood, and a continuous exchange
between the blood and the skeleton.
4.10 Strontium is similar but not identical biochemically to cal-
cium. Therefore, although some ingested strontium is deposited
in bone in a manner similar to calcium, there are metabolic mech-
anisms which perform some discrimination between the two el-
ements, so that their relative concentration when deposited in bone
is different from their relative concentration in the diet. The sim-
ilarities in metabolic pathways of strontium and calcium make it
meaningful and convenient to use ratios of the two elements in
evaluating the deposition of radioactive strontium.
4.11 Newly formed bone has about the same strontium to cal-
cium ratio as is in the blood circulating at the time of formation.
There is some discrimination against strontium between ingested
material and blood, which results primarily from preferential
renal excretion of strontium, but which may also be influenced by
preferential absorption of calcium through the gut.
4.12 Data on humans and laboratory animals indicate rather
well that there is a discrimination factor against strontium of
about four in the strontium to calcium ratio between diet and bone.
Although some experimental evidence suggests that there may be
periods during infancy and adolescence in which the discrimina-
tion factor is less than four, observations of the ratio of natural
strontium to calcium in the human skeleton as a function of age
indicate no practical difference. The strontium to calcium ratio
of the embryo and fetus is affected not only by the maternal dis-
crimination factor of four between diet and blood, but by a
placental discrimination factor of about two. The resultant dis-
crimination between maternal diet and fetal bone would therefore
be about eight under conditions of equilibrium. Presently, the
observed occurrence of strontium-90 in fetal bone is somewhat less
than predicated for conditions of equilibrium, probably because of
a calcium contribution from the maternal skeleton, which is not
now in equilibrium with the strontium-90 in the diet.
[p. 15]
4.13 Under constant intake conditions throughout life, and with
the exception of the infant, whose skeletal level of strontium would
be in transition from the prenatal to the postnatal equilibrium
values, evidence indicates that the distribution of strontium in
bone mineral would be reasonably uniform both throughout the
-------
GUIDELINES AND EEPORTS 1081
bone and throughout life. For example, measurements of the
ratio of natural strontium to calcium in over 200 skeletons of per-
sons ranging in age from stillbirths to eighty years, reported by
the Medical Research Council of the United Kingdom, November
14, 1960, indicate that the mean ratio of strontium to calcium in
humans does not increase more than about 25 percent after the
age of two years.
RADIATION DOSE FACTORS
4.14 Strontium-90 in the skeleton exists in secular equilibrium
with its daughter, yttrium-90. These nuclides emit beta radiation
with a maximum range of about six millimeters in bone and one
centimeter in soft tissue. For a non-uniform distribution of the
nuclides in bone, they would deliver a substantially more uniform
radiation dose than a similarly distributed alpha-emitting material.
When the macroscopic distribution of strontium-90 in bone is rea-
sonably even, the radiation dose can be considered as essentially
uniform.
4.15 Because of the greater range of beta radiation, bone mar-
row would receive a greater portion of the radiation dose from
strontium-90 than from an alpha-emitting material in bone. The
dose to a small bit of bone marrow surrounded by a large mass of
dense bone would approach the dose to the bone. However, the
average bone marrow dose from strontium-90 would be substan-
tially less than the bone dose. Similar considerations apply to
strontium-89.
APPLICATION OF RPG'S TO STRONTIUM-90
4.16 The Council has considered the basis for evaluation of the
biological risk associated with exposure of population groups to
strontium-90 under the conditions stated in paragraph 4.5. This
consideration included comparison with the RPG for bone marrow
and bone recommended in paragraphs 4.2 and 4.4 and comparison
with the alternate guide for bone in Section III.
4.17 For those radionuclides for which the skeleton is considered
to be the critical organ, occupational standards commonly have
been derived by estimating body burdens considered to be no more
hazardous than 0.1 microgram of radium. Two of the reasons for
adopting this approach were: (1) experience with radiation injury
to the human skeleton is largely limited to cases in which relatively
large quantities of radium have been introduced into the skeletons
of adults, whether as a result of occupational exposure or for med-
ical reasons; and (2) it is considered that, in general, the distribu-
tion of radionuclides deposited in the skeleton under occupational
-------
1082 LEGAL COMPILATION—RADIATION
conditions of exposure may be of such a nature as to make direct
comparison with X and gamma radiation uncertain.
4.18 In addition to the considerations which normally arise in
making comparisons between exposures of population groups and
exposures for occupational reasons, the manner in which occupa-
tional standards for strontium-90 have been derived appears to
make them less appropriate as a basis for comparison than the
RPG's for bone marrow and bone given in paragraphs 4.2 and 4.4.
Basically, derivation of occupational standards for strontium-90
has involved experimental determination of relative quantities of
strontium-89 and radium-226 in small laboratory animals re-
quired to produce biological damage considered to be comparable.
It was then assumed (for lack of more certain information) that,
except for an adjustment to allow for the higher retention of radon
in the human skeleton, the same ratio would hold for man. The
corresponding ratio for strontium-90 and radium-226 was esti-
mated to be twice as large as that for strontium-89 and radium-226
because the combined energy emitted by strontium-90 and yttrium-
90 per disintegration of strontium-90 is approximately twice that
emitted per disintegration by strontium-89.
4.19 This estimate of the relative quantities of strontium-90 and
radium-226 required to produce radiation hazards or effects con-
sidered to be equivalent for purposes of radiation protection to
those of radium was found to depend upon the conditions of the
experiment, particularly dose rate, and upon the effect chosen as a
measure of injury. The ratios chosen as representing the relative
hazards of strontium with respect to radium were those corre-
sponding to massive acute doses. The experimental observations
indicated that for chronic exposure at lower dose rates the relative
[p. 16]
hazards of radiostrontium are smaller by factors which range
downward to less than one-tenth and perhaps to one-hundreth of
those observed for acute doses.
4.20 Studies of individual and relative radiotoxicities of radium-
226 and strontium-90 using large laboratory animals are now in
progress. It is expected that such studies will not only provide
better comparisons of the relative hazards of strontium and radium
to experimental animals under conditions more nearly approaching
those of interest, but will provide better independent data on the
nature and degree of hazard from radioactive strontium. In ad-
dition, the use of larger animals and several species of animals is
expected to reduce the uncertainties inherent in extrapolation to
man. However, the nature of such investigations is such that
periods of time comparable to the normal lifetimes of the animals
-------
GUIDELINES AND KEPORTS 1083
are required to obtain a sufficient amount of useful information
on which to base sound conclusions.
4.21 It appears that comparisons with the bone marrow and
bone RPG's given in paragraphs 4.2 and 4.4 can be made with less
uncertainty and are more meaningful than comparisons with oc-
cupational standards for strontium-90 which have been, in turn,
based upon comparisons with radium-226. It is assumed that the
total intake of strontium-90 by individuals is such that the average
ratio of strontium-90 to calcium in the blood is constant through-
out life. This is considered to be approximately true if the ratio
of strontium-90 to calcium in the total diet (that is, in the total
amount of food and water ingested by the individual) remains
constant. In line with the principles in Report No. 1 of control of
exposure of members of the public to radiation, ratios may be av-
eraged over periods of time of the order of one year.
4.22 Under the conditions assumed, experience with stable
strontium in the normal diet as well as such data on the uptake of
radioactive strontium from the diet indicate that the distribution
of strontium-90 in the skeleton will be reasonably uniform. The
ranges of the beta rays from strontium-90 and its radioactive de-
cay product, yttrium-90, are sufficiently large that the microscopic
distribution of radiation dose to the bone (except for losses of ra-
diation near the surface) will be even more uniform. Under these
conditions, the RBE (relative biological effectiveness) of the beta
radiation does not differ markedly from that of X and gamma
radiation of quantum energy in the range between two hundred
and several hundred Kev.
4.23 It has been estimated that the average dose to bone mar-
row from strontium-90 and yttrium-90 in a skeleton of average
density is about one-third of the dose to bone. Data on experi-
mental animals indicate that the protection of a small portion of
bone marrow from a high dose of radiation may markedly lower
the incidence of leukemia. This suggests that in the case of non-
uniformity of radiation dose to the bone marrow, the average dose
is a more meaningful index of hazard than the maximum local dose
and that, for a given average, a non-uniform distribution of dose
may be less hazardous than a uniform distribution. Thus, the
RPG's for bone marrow and bone recommended in paragraphs 4.2
and 4.4 appear appropriate as a basis for the evaluation of the risk
associated with exposure of population groups to strontium-90.
4.24 The Council has emphasized, however, that in the applica-
tion of general RPG's, both the risk and the reasons for accepting
the exposure should be considered. The Council has, therefore,
reviewed past and current activities resulting in release of stron-
-------
1084 LEGAL COMPILATION—EADIATION
tium-90 to the environment, and given some consideration to fu-
ture developments. This review indicates that in general these
activities can be conducted without undue difficulty at exposures
lower than those corresponding to the RPG's. Therefore, in the
development of the guidance on intake, doses corresponding to one-
third the RPG's for bone marrow and bone to be applied to the
average of suitable samples of an exposed population group have
been used.
GUIDANCE ON INTAKE OF STRONTIUM-90
4.25 As a step in the development of guidance on intake of
strontium-90, it is necessary to determine the average daily intake
of strontium-90 which would correspond to doses of one-third the
RPG's to be applied to suitable samples of an exposed population
group. The nature of the relationship between the ratio of stron-
tium and calcium in the human diet and in the human skeleton has
been discussed in paragraphs 4.9-4.13. The data referred to in
paragraph 4.13 not only indicate that the ratio of natural stron-
tium to calcium in the skeleton does not increase significantly with
age but they show that within a general geographical area natural
[p. 17]
differences in dietary habits do not result in a large spread in the
values observed in the skeletons of individuals of all ages.
4.26 The average ratio of strontium to calcium in the human
skeleton is estimated to be about one-fourth of the ratio in the diet.
On this basis, a continuous dietary ratio of 200 micromicrocuries
of strontium-90 per gram of calcium is estimated to result in a
skeletal concentration of 50 micromicrocuries per gram of calcium
and to produce radiation doses, averaged over any age group of a
uniformly exposed population group, corresponding to approx-
imately one-third of the appropriate RPG's. This level in the ma-
ternal diet would give about one-sixth the RPG to the prenatal
individual.
4.27 The similarity between the chemical properties of stron-
tium and those of calcium makes the average ratio of strontium-90
to calcium in the diet a useful device in the development of guid-
ance on intake. In some situations, it may be desirable to con-
sider concentrations of strontium-90 and calcium in individual
items of diet. However, in general it is useful to use intake values
based on average calcium content of the diet.
4.28 Appropriate intake values will depend upon the composi-
tion of the diet and the average consumption. The minimum cal-
cium requirement in the American diet is considered to be of the
order of one gram per day. The average intake may be consider-
-------
GUIDELINES AND REPORTS 1085
ably in excess of this amount, although in some areas it is found
to be somewhat less. For the derivation of intake guidance, the
Council adopts the figure of one gram of calcium per day. On this
basis, a continuous dietary intake of 200 micromicrocuries per day
would generally correspond to the radiation doses discussed above.
4.29 It is therefore recommended that the following guidance
on transient rates of daily intake of strontium-90 to be applied to
the average of suitable samples of an exposed population group be
adopted for normal peacetime operations:
Range I 0 to 20 micromicrocuries per day
Range II 20 to 200 micromicrocuries per day
Range III 200 to 2,000 micromicrocuries per day
STRONTIUM-89
4.30 Occupational standards have related body burdens of stron-
tium-89 and strontium-90 in such a manner as to permit the same
total absorption of energy by the skeleton from one as from the
other. This results in a body burden for strontium-89 two times
that for strontium-90. Because of the shorter half-life of stron-
tium-89, 52 days as compared to 27 years, the corresponding ratio
of permissible concentrations has been estimated to be about 100.
4.31 Because of the manner in which the Council has derived
guides for exposures of population groups to strontium-90, it is
not possible to relate the two on the basis of energy comparison
alone with as high a degree of confidence as is involved in the de-
velopment of the guide for strontium-90. The guides for stron-
tium-90 depend upon the validity of the assumption of reasonable
uniformity of concentration in the skeleton. Because of the rela-
tively short half-life of strontium-89, and hence the relatively short
time in which strontium-89 atoms exist in the body, the distribu-
tion of dose is necessarily much less uniform than that from stron-
tium-90. It is, however, possible to derive, by comparison with
strontium-90, guides which represent no greater hazards than
those for strontium-90 and which are not excessively restrictive.
4.32 For this purpose, we take advantage of the current prac-
tice of permitting population exposures to be averaged over
periods of up to one year. The maximum dose rate will be ex-
perienced in areas in which new bone is being formed. Our ob-
jective is to limit the dose in any one year to the value which would
have been permitted if the radioactivity were strontium-90. For
simplicity, consider a section of "bone" of reasonable size and sup-
pose that it has been "formed" of calcium, strontium-89, and other
appropriate elements by normal process of metabolism in a period
-------
1086 LEGAL COMPILATION—RADIATION
of time short in comparison with the half-life of strontium-89. It
may be shown that the decay rate of strontium-89 is such that the
average dose rate to the bone over a period of one year after for-
mation will be only one-fifth of the initial dose rate. Because the
[p- 18]
average energy absorbed per disintegration of strontium-89 is only
half that per disintegration of strontium-90 and its yttrium daugh-
ter, in this hypothetical case ten times as much strontium-89,
measured in terms of activity, could be permitted as of strontium-
90 without increasing the average dose in one year. In subse-
quent years, of course, the dose to this section of the bone would
be essentially zero.
4.33 It is apparent that if such a section of bone were to be
built up slowly instead of instantaneously, the average dose to
this section of the bone during the ensuring year would be some-
what less. This may be demonstrated in the following manner. If
the section of bone added is reduced in thickness, a larger fraction
of the total radiation emitted by the strontium-89 in this section
escapes to adjacent material. While this escape may be com-
pensated for in part by absorption of radiation from adjacent ma-
terial, if such adjacent material is older than the section under
consideration, it must have a lower concentration of strontium-89
and, hence, the compensation cannot be complete.
4.34 On the basis of the above argument, since strontium-89 fol-
lows the same metabolic pattern as strontium-90, guidance on in-
take of ten times that used for strontium-90 will result in dose rates
to bone marrow and bone which, in any area of the skeleton, will
not exceed in any one year those permitted from strontium-90.
While these dose rates represent hazards which, over a period of
years, are certainly much less than those from continuous ex-
posure to strontium-90 at one-third the RPG, the reasons for ac-
cepting comparable risks from strontium-89 are generally less.
4.35 Therefore the following guidance on transient rates of
daily intake of strontium-89 to be applied to the average of suit-
able samples of an exposed population group is recommended for
normal peacetime operations:
Range I 0 to 200 micromicrocuries per day
Range II 200 to 2,000 micromicrocuries per day
Range III 2,000 to 20,000 micromicrocuries per day
[p. 19]
-------
GUIDELINES AND REPORTS 1087
4.1b(l) RADIATION PROTECTION GUIDANCE FOR FEDERAL
AGENCIES (MEMORANDUM FOR THE PRESIDENT),
FEDERAL RADIATION COUNCIL
September 26,1961, 26 Fed. Reg. 9057 (1961)
MEMORANDUM FOR THE PRESIDENT
SEPTEMBER 13,1961.
Pursuant to Executive Order 10831 and Public Law 86-373, the
Federal Radiation Council herewith transmits its second report to
you concerning findings and recommendations for guidance for
Federal agencies in the conduct of their radiation protection activi-
ties.
Background. On May 13, 1960, the first recommendations of the
Council were approved by the President and the memorandum
containing these recommendations was published in the FEDERAL
REGISTER on May 18, 1960. There was also released at the same
time, Staff Report No. 1 of the Federal Radiation Council, entitled,
"Background Material for the Development of Radiation Protec-
tion Standards," dated May 13, 1960.
The first report of the Council provided a general philosophy
of radiation protection to be used by Federal agencies in the con-
duct of their specific programs and responsibilities. It introduced
and outlined the term "Radiation Protection Guide" (RPG). It
provided numerical values for Radiation Protection Guides for the
whole body and certain organs of radiation workers and for the
whole body of individuals in the general population, as well as an
average population gonadal dose. It introduced as an operational
technique, where individual whole body doses are not known, the
use of a "suitable sample" of the exposed population in which the
guide for the average exposure of the sample should be one-third
the RPG for the individual members of the group. It emphasized
that this operational technique should be modified to meet special
situations. In selecting a suitable sample particular care should
be taken to assure that a disproportionate fraction of the average
dose is not received by the most sensitive population elements.
The observations, assumptions, and comments set out in the mem-
orandum published in the FEDERAL REGISTER, May 18, 1960, are
equally applicable to this memorandum.
This memorandum contains recommendations for the guidance
of Federal agencies in activities designed to limit exposure of
members of population groups to radiation from radioactive mate-
rials deposited in the body as a result of their occurrence in the
environment. These recommendations include: (1) Radiation
Protection Guides for certain organs of individuals in the general
population, as well as averages over suitable samples of exposed
-------
1088 LEGAL COMPILATION—RADIATION
groups; (2) guidance on general principles of control applicable
to all radionuclides occurring in the environment; and (3) specific
guidance in connection with exposure of population groups to
radium-226, iodine-131, strontium-90, and strontium-89. It is the
intention of the Council to release the background material lead-
ing to these recommendations as Staff Report No. 2 when the rec-
ommendations contained herein are approved.
Specific attention was directed to problems associated with
radium-226, iodine-131, strontium-90, and strontium-89. Ra-
dium-226 is an important naturally occurring radioactive mate-
rial. The other three were present in fallout from nuclear weap-
ons testing. They could, under certain circumstances, also be
major constituents of radioactive materials released to the envi-
ronment from large scale atomic energy installations used for
peaceful purposes. Available data suggest that effective control
of these nuclides, in cases of mixed fission product contamination
of the environment, would provide reasonable assurance of at least
comparable limitation of hazard from other fission products in
the body.
Establishment of the Federal Radiation Council followed a period
of public concern incident to discussions of fallout. While stron-
tium-90 received the greatest popular attention, exposures to
cesium-137, iodine-131, strontium-89 and, in still lesser degrees
to other radionuclides, are involved in the evaluation of over-all
effects. The characteristics of cesium-137 lead to direct compari-
son with whole body exposures for which recommendations by the
Council have already been made.
Studies by the staff of the Council indicate that observed con-
centrations of radioactive strontium in food and water do not
result in concentrations in the skeleton (and consequently in radia-
tion doses) as large as have been assumed in the past. However,
concentrations of iodine-131 in the diets of small children, par-
ticularly in milk, equal to those permitted under current standards
would lead to radiation doses to the child's thyroid which, in com-
parison with the general structure of current radiation protection
standards, would be too high. This is because current concentra-
tion guides for exposure of population groups to radioactive mate-
rials in air, food, and water have been derived by application of
a single fraction to corresponding occupational guides. In the
case of iodine-131 in milk, consumption of milk and retention of
iodine by the child may be at least as great as by the adult, while
the relatively small size of the thyroid makes the radiation dose
to the thyroid much larger than in the case of the adult. In addi-
tion, there is evidence that irradiation of the thyroid involves
-------
GUIDELINES AND REPORTS 1089
greater risk to children than to adults.
Recommendations as to Radiation Protection Guides. The Fed-
eral Radiation Council has previously emphasized that establish-
ment of radiation protection standards involves a balancing of
the benefits to be derived from the controlled use of radiation and
atomic energy against the risk of radiation exposure. In the
development of the Radiation Protection Guides contained herein,
the Council has considered both sides of this balance. The Coun-
cil has reviewed available knowledge, consulted with scientists
within and outside the Government, and solicited views of inter-
ested individuals and groups from the general public. In particu-
lar, the Council has not only drawn heavily upon reports published
by the International Commission on Radiological Protection
(ICRP), the National Committee on Radiation Protection and
Measurements (NCRP), and the National Academy of Sciences
(NAS), but has had during the development of the report the
benefit of consultation with, and comments and suggestions by,
individuals from NCRP and NAS and of their subcommittees.
The Radiation Protection Guides recommended below are consid-
ered by the Council to represent an appropriate balance between
the requirements of health protection and of the beneficial uses
of radiation and atomic energy.
It is recommended that:
1. The following Radiation Protection Guides be adopted for
normal peacetime operations.
TABLE I—RADIATION PROTECTION GUIDES FOR CERTAIN BODY ORGANS IN RELATION TO EXPOSURE
OF POPULATION GROUPS
RPG for average
Orean RPG for inc|i- of suitable sam-
viduals pie of exposed
population group
Thyroid 0.5 rem per year. 1.5 rem per year
Bone marrow 0.17 rem per year. 0.5 rem per year
Bone 0.5 rem per year. 1.5 rem per year
Bone (alternate guide) 0 001 micrograms of Ra-226 in the 0.003 micrograrm of Ra-226 in the
adult skeleton or the biological adult skeleton or the biological
equivalent of this amount of Ra-226. equivalent of this amount of Ra-226.
It will be noted that the preceding table provides Radiation Pro-
tection Guides to be applied to the average of a suitable sample
of an exposed population group which are one-third of those apply-
ing to individuals. This is in accordance with the recommenda-
tions in the first report of the Council concerning operational
techniques for controlling population exposure. Since in the case
of exposure of a population group to radionuclides the radiation
doses to individuals are not usually known, the organ dose to be
-------
1090 LEGAL COMPILATION—RADIATION
used as a guide for the average of suitable samples of an exposed
population group is also given as an RPG.
Recommendations as to general principles. Control of popula-
tion exposure from radionuclides occurring in the environment is
accomplished in general either by restriction on the entry of such
materials into the environment or through measures designed to
limit the intake by members of the population of radionuclides
already in the environment. Both approaches involve the con-
sideration of actual or potential concentrations of radioactive
material in air, water, or food. Controls should be based upon an
evaluation of population exposure with respect to the RPG. For
this purpose, the total daily intake of such materials, averaged
over periods of the order of a year, constitutes an appropriate
criterion.
The control of the intake by members of the general population
of radioactive materials from the environment can appropriately
involve many different kinds of actions. The character and import
of these actions may vary widely, from those which entail little
interference with usual activities, such as monitoring and surveil-
lance, to those which involve a major disruption, such as condem-
nation of food supplies. Some control actions may require pro-
longed lead times before becoming effective, e.g., major changes
in processing facilities or water supplies. The magnitude of con-
trol measures should be related to the degree of likelihood that the
RPG may be exceeded. The use of a single numerical intake
value, which in part has been the practice until now, does not in
many instances provide adequate guidance for taking actions
appropriate to the risk involved. For planning purposes, it is
desirable that insofar as possible control actions to meet contin-
gencies be known in advance.
It is recommended that:
2. The radiological health activities of Federal agencies in con-
nection with environmental contamination with radioactive mate-
rials be based, within the limits of the agency's statutory respon-
sibilities, on a graded series of appropriate actions related to ranges
of intake of radioactive materials by exposed population groups.
In order to provide guidance to the agencies in adapting the
graded approach to their own programs, the recommendations
pertaining to the specific radionuclides in this memorandum con-
sider three transient daily rates of intake by suitable samples of
exposed population groups. For the other radionuclides, the
agencies can use the same general approach, the details of which
are considered in Staff Report No. 2. The general types of action
appropriate when these transient rates of intake fall into the
-------
GUIDELINES AND KEPORTS 1091
different ranges are also discussed in Staff Report No. 2. The
purpose of these actions is to provide reasonable assurance that
average rates of intake by a suitable sample of an exposed popu-
lation group, averaged over the sample and averaged over periods
of time of the order of one year, do not exceed the upper value of
Range II. The general character of these actions is suggested in
the following table.
TABLE M—GRADED SCALES OF ACTION
Ranges Of transient rvartprl sralo nf artinn
rates of daily intake Graded scale of actlon
Range I Periodic confirmatory surveillance as necessary.
Range II Quantitative surveillance and routine control.
Range III Evaluation and application of additional control measures as necessary.
Recommendations on Ra-226, 1-131, Sr-90, and Sr-89. The
Council has given specific consideration to the effects on man of
rates of intake of radium-226, iodine-131, strontium-90 and stron-
tium-89 resulting in radiation doses equal to those specified in the
appropriate RPG's. The Council has also reviewed past and
current activities resulting in the release of these radionuclides to
the environment and has given consideration to future develop-
ments. For each of the nuclides three ranges of transient daily
intake are given which correspond to the guidance contained in
Recommendation 2, above. Routine control of useful applications
of radiation and atomic energy should be such that expected aver-
age exposures of suitable samples of an exposed population group
will not exceed the upper value of Range II. For iodine-131 and
radium-226, this value corresponds to the RPG for the average
of a suitable sample of an exposed population group. In the
cases of strontium-90 and strontium-89, the Council's study indi-
cated that there is currently no known operational requirement
for an intake value as high as the one corresponding the RPG.
Hence, a value estimated to correspond to doses to the critical
organ not greater than one-third of the RPG has been used.
The guidance recommended below is given in terms of transient
rates of (radioactivity) intake in micromicrocuries per day. The
upper limit of Range II is based on an annual RPG (or lower, in
case of radioactive strontium) considered as an acceptable risk
for a lifetime. However, it is necessary to use averages over
periods much shorter than a lifetime for both radiation dose rates
and rates of intake for administrative and regulatory purposes.
It is recommended that such periods should be of the order of
one year. It is to be noted that values listed in the tables are
-------
1092 LEGAL COMPILATION—RADIATION
much smaller than any single intake from which an individual
might be expected to sustain injury.
It is recommended that:
3. (a) The following guidance on daily intake be adopted for
normal peacetime operations to be applied to the average of
suitable samples of an exposed population group:
TABLE III—RANGES OF TRANSIENT RATES OF INTAKE (MICROMICROCURIES PER DAY) FOR USE IN GRADED
SCALE OF ACTIONS SUMMARIZED IN TABLE II.
Radionuclides
Radium-226
lodme-1311 . .
Strontium-90
Strontium-89
Range 1
. 0-2
0-10
. 0-20
. . 0-200
Range II Range III
2-20 20-200
10-100 100-1,000
20-200 200^-2,000
200-2,000 2,000-20,000
'In the case of iodme-131, the suitable sample would inc ude only small children. For adults, the RPG
for the thyro.d would not be exceeded by rates of intake higher by a factor of 10 than those applicable to
small children.
(b) Federal agencies determine concentrations of these radio-
nuclides in air, water, or items of food applicable to their particu-
lar programs which are consistent with the guidance contained
herein on average daily intake for the radionuclides radium—226,
iodine-131, strontium-90, and strontium-89. Some of the gen-
eral considerations involved in the derivation of concentration
values from intake values are given in Staff Report No. 2.
It is recommended that:
4. For radionuclides not considered in this report, agencies use
concentration values in air, water, or items of food which are
consistent with recommended Radiation Protection Guides and
the general guidance on intake.
In the future, the Council will direct attention to the develop-
ment of appropriate radiation protection guidance for those radio-
nuclides for which such consideration appears appropriate or
necessary. In particular, the Council will study any radionuclides
for which useful applications of radiation or atomic energy require
release to the environment of significant amounts of these nuclides.
Federal agencies are urged to inform the Council of such situations.
ABRAHAM RIBICOFF,
Chairman,
Federal Radiation Council.
The recommendations numbered "1" through "4" contained in
the above memorandum are approved for the guidance of Federal
agencies, and the memorandum shall be published in the FEDERAL
REGISTER.
JOHN F. KENNEDY.
-------
GUIDELINES AND REPORTS 1093
4.1c HEALTH IMPLICATIONS OF FALLOUT FROM NUCLEAR
WEAPONS TESTING THROUGH 1961, REPORT NO. 3 OF THE
FEDERAL RADIATION COUNCIL, MAY 1962
CONTENTS Page
Report of the Federal Radiation Council 1
Appendix A Omitted
Appendix B in this
Acknowledgment Publication
[P- iii]
REPORT OF THE FEDERAL RADIATION COUNCIL
HEALTH IMPLICATIONS OF FALLOUT
FROM NUCLEAR WEAPONS TESTING THROUGH 1961
The Federal Radiation Council has considered available infor-
mation on radiation doses and possible health effects of atmos-
pheric nuclear weapons testing. Before discussing the estimates
made in this report in detail, it is appropriate to point out the
difficulties of being precise in this field.
Although a large and expanding program for measuring radia-
tion levels at a number of locations throughout the United States
has been in effect for a number of years, the application of such
data to the whole country, to an extended time period, or to the en-
tire population involves assumptions than can not be completely
validated. Furthermore, while a considerable body of information
has been accumulated on the effects of radiation on animals and
man, the possible effects of low doses delivered at low dose rates
are insufficiently known to permit firm conclusions about the ex-
tremely low exposures resulting from fallout. Current experi-
mental techniques are not good enough to detect biological effects
at the low levels of worldwide fallout from nuclear tests.
Any possible manifestations resulting from fallout radiation will
not be unique, for all of the diseases and disabilities known to be
caused by radiation also occur for other reasons. Whatever effects
might be produced by fallout could only be reflected in statistical
increases in the number of conditions already present in the pop-
ulation. Any individual effects would be so diluted by space and
time that they would not be recognizable among the much larger
number of identical effects arising from other causes, among
which they would be interspersed.
Finally, any proper understanding of estimates in this field must
take into account the many different ways in which similar or
-------
1094 LEGAL COMPILATION—RADIATION
even identical data can be expressed. Many of the apparent dif-
ferences among scientists arise from different forms of presenta-
tion. Two approaches have been used. One estimates the risk of
damage to a single person. This risk is extremely small in com-
parison with others which people normally accept. The second
approach considers possible effects on a large population for a year
or a generation or for several generations totaling hundreds of
years. Even a very small proportion of affected individuals will,
in a very large population for a long period of time, amount to an
impressive total number of individuals.
ESTIMATED RADIATION EXPOSURE FROM TESTING
Any consideration of possible health effects from fallout must
begin with the radiation doses to which people are exposed as a
result of such tests.
A sharp distinction must be made between the devastating ef-
fects of "local" fallout in a nuclear attack on an unshielded popula-
tion and the effects of fallout from weapons testing. Weapons
testing creates far smaller total amounts of fission products so
that its fallout is far less than that which would result from nu-
clear war. Furthermore, the tests are planned to avoid local fall-
out or to confine it to locations where it will have minimal effects.
Hence, in weapons testing the problem is largely confined to de-
layed fallout which decays greatly in the upper atmosphere and is
dispersed at low concentrations over the earth's surface. This
report is concerned primarily with the effects of such delayed
fallout.
Dose estimations must take into account exposure from all
sources; external, and internal through ingestion of food and water
and inhalation. Some radioactive elements may concentrate to
different extents in various parts of the body. Those which tend
to concentrate in a certain organ will selectively irradiate that
organ. Thus a thyroid dose, for example, represents the sum of
the whole-body dose from a variety of substances plus the extra
dose from iodine-131, an element which tends to concentrate in the
thyroid gland. In addition, some elements are taken up more
effectively at one age than another. For example, the proportion
of strontium-90 retained in the growing bones of children is
greater than that retained in the bones of adults ingesting the
same foods. Furthermore, different sources of radiation give off
different kinds of radiation having different biological effects, so
that doses cannot be directly compared. These points should in-
dicate the difficulty of referring to any one exposure level from a
-------
GUIDELINES AND REPORTS 1095
particular source without identifying what kind of a dose and
what part of the body is involved.
Estimates of doses from fallout from tests through 1961 in
millirems, a unit of ionizing radiation dose, are given in Table I
and discussed further in Appendix "A". Because of uncertainties
and the variety of necessary assumptions, these estimates are
expressed as ranges of values within which the average exposure
over the United States is expected to lie. The values given apply to
the United States, and are somewhat higher than those for most
of the rest of the world. Doses to the whole-body and reproductive
cells represent an average for all age groups in the entire popula-
tion. Doses to bone and bone marrow are average values for those
who were infants at the time of highest concentrations of the
particular isotopes irradiating these organs; values averaged for
all age groups will be lower.
[p. 1]
The half-life of radioactive iodine, the principal source of the
thyroid dose, is only 8 days and the peak dose rates persist for a
relatively short period of time. For this reason thyroid doses are
not included in the table. Doses to the thyroid from the major
past tests were estimated to have ranged from 100 to 200 millirems
per year during and immediately following periods of testing.
These values apply only to individuals who were infants at the
time of highest concentration of radioactive iodine. The average
value for all age groups was about a tenth as much. Although
data from which thyroid doses during 1957-58 can be estimated
are limited, it is likely that there was much geographic variation,
and in some limited areas of the United States the average thyroid
doses were probably many times the national average.
The whole-body dose due to the carbon-14 produced by all tests
through 1961 has been included but not separately listed in Table
I. It is estimated to total from 10 to 15 millirems during the first
thirty-year period. The dose rate will decrease much more rapidly
than would be predicted on the basis of the carbon-14 radioactive
half-life of 5,700 years because of the absorption of the radio-
active carbon dioxide from the atmosphere into the ocean. After
about 200 years the dose rate from carbon-14 will have been re-
duced to a total of about 0.75 millirem during a thirty-year period.
To put these dose levels in some perspective, Table I compares
them with exposures from natural background and with the Radia-
tion Protection Guides of the Federal Radiation Council. The
comparisons indicate that doses from fallout have generally been
a small fraction of the Guides for population groups.
Background radiation arises from naturally radioactive mate-
-------
1096 LEGAL COMPILATION—RADIATION
rials such as carbon-14 and potassium-40 in the human body, ra-
dium in the earth's crust, and cosmic radiation from outer space.
Man has always been exposed to these radiations. Natural back-
ground radiation varies from place to place, both with elevation
and with radioactive content of local materials. In the United
States these values have been observed to range from 70 to 200
millirems per year. The value for background radiation given in
Table I is a weighted average for the entire United States
population.
The estimated values given in Table I for whole-body exposures
from fallout are considerably less than the exposures from natural
sources. Over a period of 30 years the average whole-body dose
from all testing through 1961 will be between 60 and 130 millirems
compared to 3,000 millirems from background. Thus testing
through 1961, including the contribution from carbon-14, will,
over this thirty-year period, increase exposures over natural back-
ground by less than five percent. Seventy-year average bone
doses, when similarly compared, are increased less than ten per-
cent. Any further testing will of course, increase the exposure.
The fact that exposure from some sources is generally accepted
without question should not in itself be a reason for accepting
exposure to added levels of man-made radiation. However, com-
parison of exposure levels with those of natural background does
provide some indication of the significance of increases from fall-
out. One normally considers variation in exposure from natural
sources to be of little significance. For example, a resident of the
East Coast contemplating a move to a high-altitude location in the
West is unlikely to know or attach any importance to the fact that
his exposure to background radiation will be appreciably increased
—more than twenty-five percent at elevations above one mile.
Another basis of comparison is the radiation exposure received
from medical diagnostic procedures in the United States. It has
been estimated that a person in the United States will accumulate
a genetically effective dose of the order of 1,000 millirems over a
thirty-year period. There are, however, wide fluctuations in the
exposures to the reproductive cells from the diagnostic procedures.
ESTIMATES OF BIOLOGICAL EFFECTS
Much available evidence indicates that any radiation is po-
tentially harmful. However, effects become increasingly difficult
to demonstrate below 10,000 millirems, and impossible to detect
by present techniques at the very low dose levels from fallout.
Nevertheless, it is virtually certain that genetic effects can be pro-
duced by even the lowest doses. These effects in the children of
-------
GUIDELINES AND REPORTS 1097
exposed parents and all future generations may be of many kinds,
ranging from minor defects too small to be noticed to severe dis-
ease and death.
In the case of somatic effects, i.e., effects directly on the persons
exposed, the evidence is insufficient to prove either that there is a
dosage level below which no damage occurs (the "damage thresh-
old" hypothesis) or that there is some risk of damage at any dos-
age level, no matter how low (the "no threshold" hypothesis). It
may well be that some effects are of one kind, some of the other.
Dose rate is important; a protracted dose is much less effective
than the same total dose given in a short time.
Estimates have been made by national and international groups
of scientists of the number of possible adverse health effects that
might occur from various exposure levels. Tables II and III apply
[p. 2]
some of these estimates to the exposure levels from all testing
through 1961 to indicate the possible adverse health effects in the
United States population that might result from this testing.
United States figures have been used because knowledge of dose
levels and of health effects occurring in the absence of testing is
more complete for this country than on a worldwide basis. For
convenience in expressing the concepts and calculations in this
report, the population of the United States has been taken as ap-
proximately one-tenth of the population in the same latitudes of
the northern hemisphere, and as one-twentieth of the population
of the entire world. The figures in Table II on the possible number
of adverse health effects from testing through 1961 may be multi-
plied by 10 to provide a rough estimate of comparable worldwide
effects with the exception of carbon-14, for which a factor of
approximately 20 must be applied.
Table II and Appendix "B" give numerical estimates of the
effects of fallout on one category of genetic effects—severe physical
and mental defects. This category includes the hereditary com-
ponent of such things as congenital malformations, blindness,
deafness, feeblemindedness, muscular dystrophy, hemophilia and
mental diseases.
In Table II the estimated numbers of radiation effects are given
as three values. The upper figure is the best estimate based on
radiation-induced mutation rates in mice, and on the spontaneous
incidence of these defects in man. The other figures represent the
range within which the true value may reasonably be expected to
lie.
As shown in the table, about ten percent of the number that may
result in all time from weapons tests through 1961 are estimated
-------
1098 LEGAL COMPILATION—RADIATION
to occur in the first generation—the children of parents exposed
to this fallout. The remaining ninety percent occur in decreasing
numbers in succeeding generations. Somatic effects appear only
in the irradiated individual himself, and not in his offspring. The
manifestations of particular concern are leukemia and other types
of cancer.
The radiation dose from carbon-14 is spread over an enormous
period of time extending through many thousands of years. The
number of mutations from carbon-14, when exposure over all time
is considered, is estimated to be greater than from other radio-
active elements produced in nuclear detonations. These mutations
will, however, be distributed over a much longer time with a much
smaller number in any one generation.
In addition to the gross defects listed in Table II, there may be
an unknown but probably a considerably larger number of muta-
tions with less obvious effects such as minor physical abnormal-
ities, mild diseases, impairment of physiological functions, and
reduced resistance to infection or other stresses of life. Part of
this damage will result in a lowered probability of survival at
various ages.
Reduced viability of this kind has been consistently found in
mouse experiments. The best data on mice are for the infant and
embryonic deaths. To the extent that mouse data can be applied
to man, the results indicate that the radiation-induced mortality of
embryos and infants in the first generation after irradiation is
probably larger, perhaps five times larger, than the number of in-
duced defects of the type estimated in Table II. Numerical esti-
mates are not given for such effects because of uncertainties as to
the comparability of these effects in mice and humans. This is the
viewpoint of those who have done much of the experimental work
in this field.
Mutations which have a mild effect on the individual may cause
substantial damage in the aggregate. This is because the mildness
permits these mutations, such as slight reductions in viability and
other less obvious effects, to persist in the population longer than
mutations with severe effects, and thus to affect a correspondingly
greater number of persons. There are no data which would per-
mit these effects to be assessed with sufficient accuracy to permit
numerical estimates.
If, however, numerical estimates are made of all these genetic
effects, both those which are likely and those which are more spec-
ulative, the aggregate of these estimates when counted as the total
number of individuals affected throughout the world in future
generations leads to very large numbers. Likewise, large num-
-------
GUIDELINES AND REPORTS 1099
bers can be obtained when other effects or deaths from any cause
are totaled over large populations and many generations. On the
other hand, it must be emphasized again that whatever the genetic
effects of fallout radiation from weapons testing through 1961
may be, the total effect will certainly be considered less than that
occurring inescapably from background radiation. This, in turn,
is considerably less than the effects from other factors which de-
termine the total natural mutation rate.
Estimates for two kinds of somatic effects, leukemia and bone
cancer, are given in Table III. As mentioned earlier, it is not
known whether or not there is a threshold dose below which these
diseases are not produced. If a threshold exists, fallout radiation
may produce no additional cases, and the lower limits of zero re-
flect this possibility.
The upper estimates in Table III are made by assuming the
effect of a low dose, delivered at a low dose rate, to be proportional
to the effect of a high dose delivered at a higher dose rate. The
estimates for the upper limits are probably too high because no
allowance had been made for the possibility that a given dose is
[p. 3]
less effective when received slowly over a long period of time.
Thus the range of numbers given in Table III is reasonably certain
to bracket the correct value.
There are other possible somatic effects of radiation such as
malignancies (other than leukemia and bone cancer) and general
effects such as life shortening. Among these malignancies is can-
cer of the thyroid, a possible effect from exposure to radioiodine.
Table III includes no data on the possible incidence of this effect
because estimates, like those recognized by national and inter-
national groups of scientists for possible leukemia and bone cancer
effects, have not been made for cancer of the thyroid. However,
from what little is known about the effect of radioiodine, including
data obtained from human exposures at very high levels, the like-
lihood of any possible thyroid effects has been considered to be
about the same as other malignancies for comparable exposures.
Even less information is available as to possible increases in all
these other effects than is available for leukemia and bone cancer.
To put these estimates of possible adverse health effects in some
perspective, Tables II and III also include the total number of these
same effects occurring in the United States from all causes.
CONCLUSIONS
We cannot say with certainty what health hazards are caused
by fallout from nuclear testing. We expect there will be some
-------
1100 LEGAL COMPILATION—RADIATION
genetic effects; other effects such as leukemia and cancer are more
speculative and may not occur at all. We can observe that, com-
pared to the number of these same adverse biological effects
occurring wholly apart from testing, the additional cases that
might be caused by testing are a very small quantity. We conclude
that nuclear testing through 1961 has increased by small amounts
the normal risks of adverse health effects.
[p. 4]
4.1d ESTIMATES AND EVALUATION OF FALLOUT IN THE
UNITED STATES FROM NUCLEAR WEAPONS TESTING
CONDUCTED THROUGH 1962, REPORT NO. 4 OF THE
FEDERAL RADIATION COUNCIL, MAY 1963
CONTENTS
Page
List of Tables and Figures 1
Summary 2
Section I—Introduction 3
Section II—History of Nuclear Weapons Testing 4
Section III—Atmospheric Transport and Distribution of Fallout 6
Section IV—Radionuclides in the Diet and in People 11
Section V—Radiation Dose Estimates 21
Section VI—Evaluation 25
Glossary of Terms 28
Appendix—F.R.C. Report No. 3, "Health Implications of Fallout From omitted i
Nuclear Weapons Testing Through 1961," May 1962 this publicatio
[p. iii]
LIST OF TABLES AND FIGURES
Table
1 Approximate Fission and Total Yields of Nuclear Weapons Tests Con-
ducted in the Atmosphere by All Nations.
2 Approximate Fission and Total Yields of Atmospheric Tests Conducted in
1962.
3 Approximate Fission Yields Injected into the Stratosphere in 1961 and
1962.
4 Expected Annual Deposition of Strontium-90 in U.S.
5 Average Strontium-90 Content of the U.S. Total Diet.
6 Average Percent Contributions of Diet Categories.
7 Average Strontium-90 Content of Milk in the U.S.
8 Strontium-90 Content of Wheat and Flour in the U.S.
9 Average Strontium-90 Content of Human Bone in the U.S.
10 Radionuclide Concentrations in Pasteurized Milk.
11 Average Cesium-137 Measured and Predicted Concentrations in Man and
Milk.
-------
GUIDELINES AND REPORTS 1101
Table
12 Estimated Radiation Doses in the "Wet" Areas from Testing Conducted in
1962.
13 Estimated Radiation Doses in the "Wet" Areas of the U.S. from all
Nuclear Weapons Testing Conducted through 1962.
Figure
1 Schematic Representation of "Wet" and "Dry" Areas in the Continental
U.S.
2 Mean Distribution of Strontium-90 Observed by the STARDUST Program.
[p. 1]
SUMMARY
As a sequel to a similar report last spring, the Federal Radiation
Council has again made a full study and analysis of fallout ex-
pected in the current year from nuclear tests in the past. In this
case the report covers fallout expected in the next few years from
Soviet and United States tests conducted to date.
Although absolute fallout levels in the U.S. in 1963 will probably
be substantially increased over 1962 if rainfall is normal, they will
still be, in relative terms far short of figures which would cause
concern or justify counter-measures. Cumulative whole-body
radiation doses from all past tests is estimated to be 110 millirems
in 30 years, which is about one-thirtieth the exposure from natural
sources such as soil, rocks, and building materials. The special
cases of iodine-131 and strontium-90, the two radionuclides of most
concern to the public, have been thoroughly reviewed and specifi-
cally included in the general conclusion. The Council concludes
that the health risks from radioactivity in foods, now and over the
next several years, are too small to justify countermeasures to
limit intake of radionuclides by diet modifications or altering the
normal distribution and use of food, particularly milk and dairy
products.
The substantial increase in absolute amounts of fallout is due
primarily to Soviet nuclear tests. The amount of fission yield in
the thermonuclear test explosions is a measure of the quantity of
strontium-90 and other fission products produced by the tests.
The total yield of thermonuclear explosions is a measure of the
carbon-14 produced. Since the Soviet Union ended the three-year
moratorium by resuming nuclear tests in 1961. Soviet testing has
produced 85 megatons of fission yield, and U.S. testing 16 mega-
tons.
This report updates weapons testing information to include all
tests conducted through 1962. The USSR conducted atmospheric
tests at levels of 120 megatons (MT) total yield and 25 MT fission
yield in 1961; 180 MT total yield and 60 MT fission yield in 1962.
-------
1102 LEGAL COMPILATION—RADIATION
A few of the underground tests conducted by the U.S. in 1961
resulted in some venting to the atmosphere. The U.S. conducted
a series of atmospheric tests in the Pacific at a level of 37 MT
total yield and 16 MT fission yield in 1962 plus a few low yield
tests at the Nevada Test Site.
Measurements of strontium-90 in food supplies and the total
diet in the U.S. show that the levels rose from a value of 4-8
strontium units (SU) in 1961 to 8-13 SU in 1962, and may rise to
a peak value of 50 SU in 1963. The predicted concentrations of
strontium-90 in milk for 1963 are twice the value observed in 1962
and about 4 times the values observed in 1961. The strontium-90
concentrations in human bone are expected to rise from an ob-
served value of 2.6 SU in 1961 to 7 SU in 1964. The presently
estimated radiation dose to bone from all past tests is about 465
millirems in 70 years, which is about one-twentieth the exposure
from natural sources. It should be noted that these presently pre-
dicted values are no greater than those which were predicted in the
FRC Report No. 3 as likely to result from all tests conducted prior
to 1962. This is because the measured levels are lower than orig-
inally predicted.
It was estimated in 1962 that carbon-14 resulting from tests
conducted through 1961 would give an average per capita radia-
tion dose to the whole-body including the reproductive cells of 10
to 15 millirems in the first 30 years. It is now estimated that the
carbon-14 produced by testing conducted in 1962 will produce a
comparable radiation dose in the first 30 years. When the carbon-
14 now in the atmosphere has equilibrated with the oceans, the
natural levels will be increased by about 4 percent instead of the
2 percent previously reported.
As an addition, FRC Report No. 3, "Health Implications of Fall-
out from Nuclear Weapons Testing through 1961," is attached for
reference.
[P. 2]
SECTION I
INTRODUCTION
1.1 The Federal Radiation Council evaluated the health implica-
tions of fallout from nuclear weapons testing conducted through
1961 in its Report No. 3 issued in May 1962. Since that report
was prepared, additional atmospheric testing of nuclear weapons
has been conducted by the USSR and U.S. governments. The
purpose of the present „ is to:
(a) Update the information concerning the scale of weapons testing pro-
grams conducted by all nations;
-------
GUIDELINES AND REPORTS 1103
(b) Summarize the radiation doses experienced in the past and expected in
the future;
(c) Evaluate the change in the inventories of long-lived radionuclides in the
stratosphere and on the ground resulting from these tests;
(d) Predict the probable levels of fallout that may be expected in 1963 and
subsequent years in the food supplies of the nation; and
(e) Draw conclusions about the suitability of food products for human con-
sumption in view of the predicted levels of radionuclides.
1.2 The predictions of future fallout levels from testing con-
ducted through 1962 are based on the information available
through March 1963. The estimates of doses received in 1962 are
based on extensive measurements of the radionuclide concentra-
tions in air, rain, soil, water supplies, food supplies, and people.
[p. 3]
SECTION II
HISTORY OF NUCLEAR WEAPONS TESTING
2.1 The atmospheric testing of nuclear devices inevitably intro-
duces radioactive nuclides into man's environment. The existence
of many of these products is transitory due to the process of
radioactive decay. Other species, notably carbon-14, are so long-
lived that they can be considered as a permanent man-made mod-
ification of the environment. Historically, major attention has
been focused on the production and distribution of strontium-90
and cesium-137, both of which can lead to radiation exposure over
the full lifetime of persons now living. Of the shorter-lived radio-
nuclides, iodine-131 has been emphasized.
2.2 The production of strontium-90 and other fission products
depends on the fission yields of the devices. The production of
carbon-14 depends on the total fission plus fusion yields of the
devices.
2.3 Table 1 summarizes the fission and total yields of atmos-
pheric testing conducted by all nations through December 1962.
As of January 1959, the strontium-90 inventory was estimated to
be 9.2 megacuries produced by the detonati i of 92 megatons of
fission yield, 40 megatons of which had been detonated in 1957 and
1958.' Of this inventory, it was estimated that 3 megacuries had
deposited as "close in" fallout near the test sites. Of the 6 mega-
curies then available for worldwide deposition, 3 megacuries had
been deposited as worldwide deposition, and 3 megacuries were
still in the atmosphere. The available inventory as of May 1961,
taking into account the decrease of 2.5 percent per year for the
radioactive decay of strontium-90, was estimated as 5.2 to 5.3
110 megatons of fission yield produce approximately 1 megacurie of strontium-90.
-------
1104 LEGAL COMPILATION—RADIATION
megacuries strontium-90. Of that quantity, 4.2 megacuries had
deposited on the ground and 1 megacurie was still in the atmos-
phere. Less than one-quarter of this atmospheric burden was in
the lower stratosphere in the northern hemisphere.
2.4 The USSR detonated an estimated 120 megatons of total
yield in 1961 of which about 25 megatons were due to fission yield.
The estimated radiation doses from this series were presented in
FRC Report No. 3, "Health Implications of Fallout from Nuclear
Weapons Testing through 1961."
2.5 The United States and the Soviet Union conducted tests in
1962 at levels shown in Table 2. U.S. and Soviet tests do not con-
tribute equally to fallout exposures in the U.S. not only because
of the difference in fission yields, but also because the distribution
and rate of deposition vary with the geographic location of the
tests and the altitude to which the weapon debris is carried. The
amounts of fission yield injected into the stratosphere by the U.S.
and the USSR in 1961 and 1962 are shown in Table 3. The total
of 57 megatons fission yield injected into the lower stratosphere in
1961 and 1962 dominates the inventory available for worldwide
deposition in 1962, and in the next few years.
[P. 4]
TABLE 1.—APPROXIMATE FISSION AND TOTAL YIELDS OF NUCLEAR WEAPONS TESTS CONDUCTED IN THE
ATMOSPHERE BY ALL NATIONS
Yield in megatons
Fission yield Total yield
Inclusive years
1945 1951
1952 1954
1955-1956
1957 1958
Subtotal
1959 1960 . .
1961
Subtotal
1962
Total
Air
19
1
5.6
31
37 8
. . . Test
25 '
63
76 i
139
Surface
.52
37
7.5
9
54
54
54
Air
19
1
11
57
69 2
120
189
217
406
Surface
57
59
17
28
1046
105
105
1 The small yield tests conducted in Nevada do not contribute significantly to the worldwide distribution
of strontium-90 to which this summary is related.
TABLE 2.—APPROXIMATE FISSION AND TOTAL YIELDS OF ATMOSPHERIC TESTS CONDUCTED IN 1962
Yield in megatons
Fission yield Total yield
U.S 16 37
U.S.S.R 60 180
Total 76 217
-------
GUIDELINES AND REPORTS 1105
TABLE 3.—APPROXIMATE FISSION YIELDS INJECTED INTO THE STRATOSPHERE IN 1961 AND 1962
Yield in megatons
Lower stratosphere ' Upper stratosphere ' Total
(MT) (MT) (MT)
U.S.S.R. (1961) 17 8 25
U.S.S.R. (1962) 30 30 60
U.S. (1962) 10 1 11
1 The lower stratosphere occupies the first few tens of thousands of feet above the tropopause and the
upper stratosphere continues to about 150,000 feet. The tropopause, on the average, is located at
30-40,000 feet in the temperate and polar zones and 50-55,000 feet in the tropical and the equatorial
zones. Debris injected above 150,000 feet is omitted from this table.
[p. 5]
SECTION III
ATMOSPHERIC TRANSPORT AND DISTRIBUTION OF FALLOUT
3.1 The future course of fission-product deposition in man's en-
vironment resulting from past nuclear detonations can be esti-
mated either from a knowledge of the amount and distribution of
these products in the atmosphere at some recent date or from an
estimate of the time, place, and amount injected into the atmos-
phere by the various test series. These data can be utilized in
conjunction with the experience and knowledge gained over the
past decade in analyzing fallout phenomenology. Studies of the
movement and deposition of debris from past test series, using
short-lived isotopes and unique radioactive tracers to identify the
sources of the debris, have added to our understanding of the role
of the atmosphere in determining the ultimate distribution of
fission products on the surface of the earth.
3.2 Although the exact mechanisms involved in the transfer of
debris from the stratosphere to the surface of the earth are not
completely understood, the general features of the distribution on
the ground are known from the available fallout data. These data
show that precipitation is the most important mechanism in de-
positing material on the surface, and that there are both a lati-
tudinal variation, with most deposition in temperate latitudes, and
a seasonal variation with maximum deposition in the spring.
3.3 On January 1, 1963, the accumulated levels of strontium-90
deposited over the United States varied from about 100 to 125
millicuries per square mile in the "wet" areas (areas of greatest
annual precipitation) to 40 to 50 millicuries per square mile in the
"dry" regions. Figure 1 shows the continental United States; the
areas considered as "wet" are closely hatched, "dry" areas are
unshaded, and intermediate precipitation regions have widely
spaced hatching.
-------
1106 LEGAL COMPILATION—RADIATION
3.4 Utilizing- sampling data obtained by the Defense Atomic
Support Agency's STARDUST Program, it is possible to compare
the burden of strontium-90 in the lower stratosphere in early 1963
with the burden approximately a year earlier. Experience in-
dictates that debris present in January up to 55,000 feet will appear
in the fallout of the coming year. Figure 2 shows the strontium-
90 concentration up to 70,000 feet, the ceiling of the sampling
aircraft, in early 1963. The stratosphere below 55,000 feet in the
northern hemisphere contained about 2 megacuries of strontium-
90 in early 1963, while about 1 megacurie was observed in the
same region in early 1962. Thus, the 1963 fallout is expected to
be about twice that of the stratospheric component in 1962, as
shown in Table 4. About 80 percent of the stratospheric burden
available for fallout in 1963 came from testing conducted in 1962.
The apparent age of the 1963 spring fallout is expected to corre-
spond to a mean production time of mid-September 1962. An
independent analysis of the input of strontium-90 based on the
fission yields given in Table 3 agrees with the estimates in Table 4.
3.5 In Table 4 the annual fallout estimates from weapons tests
already conducted have been extended, with considerable uncer-
tainty, to future years. Since the half-life of strontium-90 is 28
years, it decays at the rate of 2.5 percent per year. By 1966, radio-
active decay of the accumulated strontium-90 should exceed de-
position, resulting in a gradual lowering of the strontium-90 values
in succeeding years.
3.6 The possibility exists that fallout estimates can be in error
by a factor of two for the year 1963 and by more than a factor of
two in subsequent years. The uncertainties in the estimates of
fallout are largely due to data limitations, incomplete understand-
ing of atmospheric behavior, and year to year weather differences.
[P. 6]
-------
GUIDELINES AKD REPORTS
1107
"S
-------
1108
LEGAL COMPILATION—RADIATION
40-
80-
120-
160-
200-
240-
280-
320-
360-
400-
440-
480-
520-
560-
600-
90«N 60°N
30'N
0°
LATITUDE
30'S
100
70
60
50
40
|
30 I
5
i
I
a
I
20
60°S 90°S
Figure 2.—Mean distribution of strontium-90 (Disintegrations per minute
per 1000 standard cubic feet of air) observed by the STARDUST
Program December 1962 through January 1963 (Preliminary).
[P. 7]
TABLE 4.—EXPECTED ANNUAL DEPOSITION OF STRONTIUM-90 IN THE UNITED STATES
MILLICURIES PER SQUARE MILE
Deposition during 1962 (stratospheric component only)-
"Wet" area
"Dry" area
Accumulated deposition to January 1, 1963
"Wet" area
"Dry" area ....
Expected deposition during 1963
"Wet" area
"Dry" area ... ...
Expected deposition during 1964
"Wet" area
"Dry" area ....
Expected deposition during 1965
"Wet" area
"Dry" area ...
Most probable value
25
10
110
45
50
20
20
8
10
3
Variability
within area
15-35
5-15
100-125
40-50
30-60
10-30
10-25
5-10
5-15
2-5
Note: In each year, it is expected that about 70 per cent of the annual fallout will occur in the first 6
months of the year.
[p. 10]
-------
GUIDELINES AND REPORTS 1109
SECTION IV
RADIONUCLIDES IN THE DIET AND IN PEOPLE
4.1 Estimates of radiation doses received from fallout must take
into account exposures from all sources including sources external
to the body and those which enter the body by inhalation and in-
gestion. There is a special interest in those radionuclides that
enter the body through the diet. This section considers that part
of fallout debris which is found in the food supplies of the nation.
4.2 The most significant contributors to the internal dose to man
from fallout radionuclides are strontium-90, cesium-137, iodine-
131, strontium-89, and carbon-14. The shorter lived nuclides
iodine-131 and strontium-89 are significant in fallout only over the
first few months following a test; the others are of importance
over many years. Information concerning the appearance of these
nuclides in the diet and in man is provided in the following
paragraphs.
STRONTIUM-90
4.3 Strontium-90 is a long-lived radionuclide (half-life of 28
years) with chemical properties similar to calcium. It deposits in
bone where it has a long residence time. Its concentration in the
human body is determined by radiochemical analyses of bone spe-
cimens obtained surgically or at autopsy. Since strontium-90
emits only beta particles, the skeletal content cannot be measured
externally by instrumental methods. It enters the body in the
total diet; milk, wheat products, and vegetables are the main con-
tributors.
4.4 Historically, strontium-90 has been considered the most po-
tentially hazardous component of radioactive fallout and has been
the most widely studied. Measurements of its concentration in
human bone specimen are the most direct approach to dose esti-
mation, but the time lags in body uptake and in the collection and
analyses of specimens are a handicap in maintaining knowledge of
current concentrations in the skeleton. However, past experience
allows reasonably reliable estimates of strontium-90 in new bone 1
from total dietary intake, from the strontium-90 content of milk,
or from fallout deposition measurements.
4.5 The confidence with which estimates of strontium-90 con-
centrations in new bone can be made from a knowledge of the
strontium-90 levels in the diet has increased since the 1959 Con-
1 New bone is the bone being formed from the dietary components. In the adult it is only that
bone being re-formed or exchanged metabolically, and is a small fl action of the skeleton. In the
growing child new bone represents a much higher poition of the skeleton.
-------
1110 LEGAL COMPILATION—RADIATION
gressional Hearings on fallout. Prior to that time, diet informa-
tion was largely derived from milk sampling and from a few other
items, but the bone sampling was not correlated with diet samples.
4.6 Beginning in late 1959 the Atomic Energy Commission's
Health and Safety Laboratory (HASL) established a quarterly
survey in New York City, San Francisco, and Chicago based on
food consumption. Consumers Union collected and analyzed com-
plete diets of teen-agers for two weeks in 24 cities in November
1959 and similar collections have been made up to the present time.
The U.S. Public Health Service (USPHS) monthly institutional
diet sampling program involving the age groups 8 to 20 and now
covering institutions in 22 states began in March 1961. The Food
and Drug Administration (FDA) set up a total diet sampling
program in May 1961, and continued regional sampling of major
food items.
4.7 Because of these expanded programs, estimates of dietary
strontium-90 levels have been greatly improved since 1958. Stud-
ies of the relationships between fallout deposition levels and the
strontium-90 levels in diet and milk have provided a basis for
predicting future levels of strontium-90 in several dietary com-
ponents and in total intake. These prediction models take into
account both the uptake by plant roots from the total accumulated
deposition in the soil, and the foliar uptake of fallout deposited
during the growth period. Other factors, such as the length of the
growing season and differences in agricultural practices also lead
to variations in radionuclide concentrations in man's food supplies
even though the levels of fallout deposition appear to be similar.
Thus, the observed radionuclide levels in milk and other foods per
millicurie of strontium-90 deposited per square mile are somewhat
higher in the southern part of the U.S., than they are in the north.
Similarly, the food chain of lichen-caribou-man, which is char-
acteristic of the Far North may sometimes lead to transient levels
in food for a given level of fallout deposit many times higher than
corresponding levels in the "wet" areas of the U.S.
[P. 11]
4.8 Studies of strontium and calcium metabolism show that the
ratio of strontium-90 to calcium in new bone may be estimated as
about one-fourth of the ratio in the diet, since the body uses cal-
cium preferentially over strontium. This metabolic discrimination
against strontium may be less in infants, but the strontium-90/
calcium ratio in new bone will not be greater than that of the diet.
4.9 Based on these considerations and on fallout predictions for
1963, 1964, and 1965, as described in Section III, predictions of
-------
GUIDELINES AND KEPORTS 1111
strontium-90 levels in total diet, diet components, and bone have
been made.
TOTAL DIET
4.10 Table 5 shows the strontium-90/calcium ratios in the U.S.
total diet obtained by measurements made from 1959 through
March 1963, and values predicted in the future for the total diet
in the "wet" and "dry" areas of the U.S. Following the peaks of
13 to 18 SU (Strontium Unit—See Glossary) reached in 1959 as a
result of 1958 weapons tests, the levels dropped by 1961 to 4 to 8
SU. The rise at the end of 1962 and early 1963 resulting from
tests in 1961 and 1962 will continue to a predicted maximum of
50 SU in 1963.
4.11 These predicted values resulting from tests conducted
through 1962 can be compared with measurements made since
1959 only on the basis of average levels for broad regions. Meas-
urements made in the pasteurized milk network during 1961 and
1962 indicate that the average annual concentration of strontium-
90 in milk produced in the "wet" area of the U.S. is about 1.5
times greater than the annual average for milk produced in the
"dry" area. The maximum difference between the lowest station
in the "dry" area and the highest station in the "wet" area in 1962
was about a factor of 10 for the radionuclides of interest. The
average annual intake of radionuclides in some regions may be
about 3 times higher or 3 times lower than the overall national
average.2 The data from Table 5 show that the annual intake of
strontium-90 in a diet representative of a typical person in the
U.S. dropped from about 15 SU in 1959 to a low of about 6 SU in
1961 before the resumption of nuclear testing. The large increase
predicted for the year 1963 was not generally evident in measure-
ments made through March. However, the maximum fallout rates
are expected to have occurred during the months of April and May,
so surveillance measurements of nuclides such as cesium-137 and
strontium-89 should show sharp increases by June if these pre-
dictions are approximately correct. The decrease in subsequent
years reflects the diminished fallout rates predicted for those
years.
DIET COMPONENTS
4.12 The percentage contributions of four major diet categories
to the diet weight, strontium-90 and calcium intakes for the tri-
- This information is of interest since previous estimates have presented the analyses in terms
of the national average, whereas an attempt is being made to analyze the "wet" and "dry"
regions separately in this report.
-------
1112 LEGAL COMPILATION—RADIATION
city diet studies of the Health Safety Laboratory are shown in
Table 6. It is apparent that an attempt to substitute other diet
items for milk would decrease calcium intake more sharply than
strontium-90 and in fact increase the strontium-90/calcium ratio
of the diet. A number of studies have shown that conservative
estimates of the strontium-90/calcium ratio in the total diet may
be made by multiplying the ratio of strontium-90/calcium in milk
for a particular locality by 1.5. The strontium-90/calcium ratio in
milk may be the same as that in the diet during periods of fresh
fallout.
4.13 The levels of strontium-90 in milk measured in the past,
and predicted for the future are shown in Table 7. The measured
values of strontium-90 in the milk supply of New York City were
about 9 picocuries per liter of milk in 1959 and dropped to a low
of 8 picocuries in 1961. The concentration rose to a value of about
14 picocuries per liter of milk in 1962 and is projected to average
about 30 picocuries per liter in 1963 and then drop to values of
about 17 picocuries per liter by 1965. It should be recognized that
Table 5 considers the total diet which contains food from several
areas, while Table 7 is concerned with milk alone. The relation-
ship that the strontium units in the total diet equal 1.5 times the
strontium units in milk was derived when this relationship was
stable. The predictions in Table 5 cannot be derived from Table 7
since, as already noted, the relationship changes during periods of
fresh fallout.
4.14 The levels of strontium-90 in wheat and in white flour
measured in the past and predicted for the future are shown in
Table 8. Wheat levels are more dependent on the fallout rate com-
ponent than are milk levels and thus they vary over a wider range.
[p. 12]
4.15 The levels of strontium-90 in wheat are among the highest
found in important food items. The maximum level resulting
from past weapons testing is expected in the 1963 wheat crop and
may average as high as 250 picocuries of strontium-90/kilogram
in harvested wheat. Milling, distribution, and storage practices
bring about much lower levels in major dietary wheat products,
and also make it unlikely that levels of strontium-90 ingestion
through wheat products in any particular area will differ much
from the national average.
4.16 From 70 to 80 percent of the wheat consumed by humans
in the United States is in the form of bread made from white flour.
This wheat is produced almost entirely on the Great Plains from
Texas to North Dakota and Montana, and the concentration of
-------
GUIDELINES AND REPORTS 1113
strontium-90 has differed little from the national average in any
past year. Most of the remaining wheat is consumed in the form
of other baked goods and is produced primarily east of the Mis-
sissippi River or in the Pacific Northwest. Less than five percent
of the wheat consumed is in the form of whole wheat bread or
cereals, and very little is in the form of bran. Although the latter
products contain a higher concentration of strontium-90 than
white flour or whole wheat, the relatively small quantities con-
sumed prevent them from becoming major contributors of stron-
tium-90 in the total diet.
4.17 Water, meat, fish, poultry, eggs, sugars and fats contribute
negligible amounts of strontium-90 to the diet. Fruits and vege-
tables contribute about one-third of the total intake of strontium-
90, which is quite comparable with their weight intake. These
figures are based on the foods as prepared for eating; slightly
higher values are found in the raw unwashed items.
4.18 The levels of strontium-90 measured in the past and pre-
dicted for new bone in the future are shown in Table 9. The pre-
dicted value for new bone is taken as one-fourth the predicted
strontium-90/calcium ratio in the total diet in order to indicate the
concentrations being deposited in the skeletons of the younger age
groups. However, as pointed out in FRC Report No. 2, the mean
bone dose is a better estimate of risk inasmuch as a larger volume
of tissue is affected. Calcium and strontium-90 in new bone is
continually redistributed as the result of normal bone metabolism,
so the observed values in the skeleton would be expected to be
lower than the maximum concentration in new bone during a
relatively short period of time (i.e., one year). Thus the calcu-
lated concentrations of strontium-90 in new bone in 1963, 1964,
and 1965 are 12, 8, and 5 SU respectively, whereas the values
estimated in bone for the 0-4 age group are about 5, 7, and 7 SU
respectively in the "wet" areas of the United States and 3, 5, and
5 SU respectively in the "dry" areas.
CESIUM-137
4.19 Cesium-137, another long-lived radionuclide (half-life 30
years), distributes itself throughout soft tissue and has a relatively
short residence time in the body. Its gamma radiation allows
direct measurement in the living body with a whole-body counter.
4.20 The distribution of cesium-137 in the diet is not well de-
fined, but milk, meat, and vegetables are the main contributors.
Trends in dietary cesium-137 have been similar to those for stron-
tium-90, in that both tend to fluctuate with fallout rate. Because
of this dependence on fallout rate and the rapid turnover rate of
-------
1114 LEGAL COMPILATION—RADIATION
cesium in the body, cesium-137 levels in foods and in the body
increase and decrease more rapidly than levels of strontium-90.
Peak concentrations of cesium-137 in milk have appeared about
one month after peak fallout rates, and peaks in the balance of the
diet have appeared about one year after peak fallout rates. Peak
levels in people have been observed about seven months after peaks
in fallout rates.
4.21 Because of the differences in the mechanisms by which
cesium-137 moves through the environment, predictions for ce-
sium-137 cannot be made on the same basis as those for strontium-
90. About all that can be done is to make comparisons with pre-
vious test patterns and the corresponding observations for milk
and man, and noting that a year by year comparison is not direct
inasmuch as there are different time lags in the responses. Table
10 gives the observations on cesium-137 measured in pasteurized
milk samples by the U.S. Public Health Service from 1959 through
the first quarter of 1963. Table 11 gives measured and predicted
concentrations of cesium-137 in milk and man.
4.22 Table 10 shows that the concentration of cesium-137 in
milk in picocuries per liter, was about 4 to 5 times the correspond-
ing strontium-90 concentration in 1959; it was essentially the same
as strontium-90 in 1960 and 1961; it rose to 3 to 4 times the
strontium-90 concentration in 1962 as the result of fresh fallout
in that year. Although there is no uniform relationship between
cesium-137 and strontium-90 concentrations in milk, estimates
based on fallout rate lead to the conclusion that the average "wet"
[p. 13]
area concentrations of cesium-137 in milk may be about 140, 70,
and 30 picocuries per liter respectively in 1963, 1964, and 1965.
The anticipated concentration in man is expected to be about 150
picocuries per gram of potassium 3 in 1963 and then drop to a
value below 100 by the end of 1965.
IODINE-131
4.23 Iodine-131 is a short-lived radionuclide (half-life 8 days)
which concentrates in the thyroid gland. Its gamma radiation
allows direct measurement in the body. The residence time in the
body and the half-life are both short. Therefore iodine-131 dis-
appears in a few weeks. The significant diet contributor is milk
because the time lag between production, and distribution is only
3 Potassium is essential to life and its naturally occurring radionuclide contributes a whole-body
dose of about 20 millirems per year. It is chemically similar to cesium and is distributed through
the soft tissues of the body. Therefore, cesium concentrations in people are usually reported as the
cesium-137/potassium ratio.
-------
GUIDELINES AND EEPORTS 1115
a few days.
4.24 The U.S. Public Health Service measurements of iodine-
131 in milk are summarized in Table 10. Iodine-131 levels from
past testing are based on values observed from 1959 through
March 1963. Radioactive decay has reduced the iodine-131 result-
ing from tests conducted in 1962 to insignificant levels. The
presentation of iodine-131 levels by "wet" and "dry" areas is
included only to keep the form of the information comparable.
The deposition of iodine-131 is largely associated with material
initially injected into the troposphere and hence is not systemati-
cally related to the mean annual rainfall.
4.25 Since November 1961, the Public Health Service with the
cooperation of selected medical centers throughout the continental
United States has collected and analyzed several hundred thyroid
autopsy specimens. The thyroids were primarily from adults
experiencing a traumatic death. Iodine-131 values ranged from
0-20 picocuries per gram of thyroid with a probable mean in the
range of 5-7 picocuries per gram. Iodine-131 in the thyroid was
found only where appreciable levels of iodine-131 were observed
in the pasteurized milk network samples in the area from which
the thyroid specimen was obtained.
4.26 The highest station for iodine-131 in milk in the con-
tinental U.S. in 1962 was in Utah. A large percentage of the
observed iodine-131 occurred as the result of atmospheric tests in
Nevada. Although the Utah State Health Department reported
iodine-131 concentrations in excess of 1000 picocuries iodine-131
per liter of milk for about a week, the equivalent daily intake for
a year for the population in the milk fed would have been 103
picocuries iodine-131 per liter. Milk from individual farms or
from individual cows could, of course, be higher or lower than the
measured average for the station.
STRONTIUM-89
4.27 Strontium-89 has a half-life of 50 days, and is similar
chemically to strontium-90. It deposits preferentially in bone, and
remains there until it is reduced to a negligible level through radio-
active decay. Like strontium-90 it is a beta emitter and is meas-
ured in humans by the radiochemical analyses of bone samples
obtained at autopsy. Milk is the important dietary contributor
since time lags between deposition and the production and dis-
tribution of most other foods result in the radioactive decay of
strontium-89. Strontium-89 appears in other foods attached to
their surfaces.
-------
1116 LEGAL COMPILATION—RADIATION
4.28 The observed values for strontium-89 in milk since 1959
are given in Table 10. It can be seen that the annual average
concentration for most stations was three to four times the corre-
sponding concentration of strontium-90 for that station. Based on
the apparent age of the fission debris in the stratosphere, the
strontium-89/strontium-90 ratio in milk in 1963 may reach a
maximum value of about 8 during the first part of the year, but
due to the short half-life of strontium-89, the annual averages in
1963 should be comparable to those observed in 1962.
CARBON-14
4.29 Carbon-14 is a very long-lived radionuclide (half-life 5.760
years) produced by the interaction between neutrons and nitrogen
in the atmosphere. It is produced naturally by cosmic radiation,
and artificially by nuclear weapons. It follows non-radioactive
carbon chemically and metabolically, and is part of all living mat-
ter. Carbon-14 in the body is essentially in equilibrium with
carbon-14 in the environment. The environmental level tends to
decrease slowly as carbon-14 enters the carbonates of the deep
ocean waters and sediments. Carbon-14 emits only beta particles
and cannot be measured directly in the body. All items of the diet
contribute in proportion to their carbon content so that measure-
ments made on atmospheric carbon dioxide, which is the source of
plant carbon, can be substituted for measurements in the body.
[p. 14]
4.30 As a result of nuclear weapons tests conducted through
1958 the tropospheric level of carbon-14 was about 30 percent
above the equilibrium inventory of naturally produced carbon-14
in the atmosphere due to its normal production by cosmic radiation.
4.31 The testing conducted in 1961 and 1962 probably produced
about 100 times more carbon-14 than was produced naturally by
cosmic rays during the same period. This should raise the arti-
ficially produced carbon-14 in the atmosphere to twice the natural
levels over the next several years. This excess carbon-14 is ex-
pected to be removed from the atmosphere by exchange with the
ocean with a rate corresponding to a half-time (See Glossary) of
about 33 years. Ultimately, about 96 percent will be removed,
leaving an atmospheric level about 4 percent higher than the nat-
ural level. This conclusion is consistent with preliminary data
from the stratospheric sampling program.
[p. 15]
-------
GUIDELINES AND REPORTS
1117
TABLE 5.—AVERAGE STRONTIUM-90 CONTENT OF U.S. TOTAL DIET
(pc Sr»/g Ca)
"Wet" area
Observed
"Dry" area
1959
1960 ...
1961
1962 .
1963 (through March)
1963 . .
1964
1965
13-18
11
4-8
8 13
10
Predicted
50
30
20
9
4
3-6
4-8
8
35
20
10
TABLE 6.—AVERAGE PERCENT CONTRIBUTIONS OF DIET CATEGORIES
Approximate percent of annual
strontium-90 intake
Milk products
Gram products ...
Fruits and vegetables
Others
Total
Diet
Weight '
33
14
36
17
100
Diet
Calcium
61
15
13
11
100
N.Y.
51
16
30
3
100
Chicago
39
26
30
5
100
S.F. 2
37
24
32
7
100
1 The diet weights do not include water, coffee, tea and other nonmilk beverages.
2 S.F.—San Francisco.
[p. 16]
TABLE 7.—AVERAGE STRONTIUM-90 CONTENT IN MILK IN THE U.S.
[pcSr»/l.of milk]
1959 1 .
1960
1961
1962 .
1963 (First quarter)
1963 ...
1964 . . .
1965
New
York
9
9
8
14
16
31
20
17
"Wet" San
areas Francisco
Observed (PHS values)
14 —
9 4
9 4
15 5
18 8
Predicted
— 11
— 6
— 4
'"Dry"
areas
9
5
6
10
11
1 Based on raw milk data; dash (—) indicates no raw milk station.
-------
1118
LEGAL COMPILATION—RADIATION
TABLE 8.—STRONTIUM-90 CONTENT OF WHEAT AND FLOUR IN THE U.S.
[pc/kg]
Average from 9-15
states weighted for
production (HASL) '
Year of
Harvest
Average of FDA sampling
pared samples program
(FDA) *
Wheat Flour Wheat Flour
Wheat
Observed
1959
1960
1961
1962
48
26
23
9 — —
4 13 4
7 19 4
17
18
'56
Predicted
1962 »
1963
1964
1965
130
250
100
50
22
40
16
8
' (HASL) Health and Safety Laboratory, USAEC, New York.
2 (FDA) Food and Drug Administration, Department of Health, Education and Welfare. The "Paired
Samples" indicates that the same sample of wheat was analyzed when made into flour.
1 Incomplete—includes less than 50% of production. The 1962 predicted value is presented pending
the availability of more complete data.
[P- 17]
TABLE 9.—AVERAGE STRONTIUM-90 CONTENT OF HUMAN BONE IN THE U.S.
[pc Sr »/g Ca]
"Wet" areas
"Dry" areas
Observed (0-4 years old)
1958 1
1959
1960
1961
1962 (6 months) . .
1963 . .
1964
1965
2.0
2.7
2.4
2.6
2.9
12
8
5
2.0
2.2
1.8
0.9
1.0
Predicted (new bone) 2
9
5
3
' Data for 1958-60 are from Lamont Geological Observatory, 1961-62 are from HASL.
1 One-fourth the predicted total diet values in Table 5.
[p. 18]
-------
GUIDELINES AND REPORTS
1119
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-------
1120
LEGAL COMPILATION—RADIATION
TABLE 11.—AVERAGE CESIUM-137 MEASURED AND PREDICTED CONCENTRATIONS IN MAN AND MILK
Measured
In Man =
In milk
"wet" areas'
Washington, D.C. Los Alamos
Average
1957
1958
1959
1960
1961
1962
1963
1964
1965
'69
67
51
31
—
51 —
62 —
74 70
67 60
— 30
— —
Predicted
150
120
80
—
65
10
10
49
Predicted
140
70
30
1 July-December only.
2 Units, picocuries per gram Of potassium.
' Units, picocuries per liter of milk. (USPHS Data.)
[p. 20]
SECTION V
RADIATION DOSE ESTIMATES
Exposure from Testing Conducted in 1962
5.1 Radiation doses that could affect present and future gen-
erations as the result of nuclear weapons testing conducted through
1961 were reported in FRC Report No. 3, "Health Implications of
Fallout from Nuclear Weapons Testing through 1961." The
present report considers doses attributable to the tests conducted
in 1962 separately from the cumulative doses attributable to all
tests conducted through 1962. The major interest is to isolate
as much as possible the effects of the fallout rates expected from
1962 through 1965. Results from tests conducted in 1962 are
shown in Table 12. Estimates of doses from short-lived nuclides,
cesium-137, strontium-89, and strontium-90 were based on meas-
urements made through March 1963 plus the predicted fallout
deposition through 1965 in order to emphasize the information
which is important in the immediate future. This procedure
leaves a small percentage of the debris unaccounted for since it will
still be in the stratosphere in 1965. However, the short-term car-
bon-14 estimates and the bone and bone marrow estimates would
not be changed substantially. Estimates of radiation doses in-
curred in 1962 from tropospheric fallout were based on surveil-
lance data as shown in Table 10.
5.2 Predictions shown in Table 12 of future doses from external
-------
GUIDELINES AND REPORTS 1121
radiation from debris yet to be deposited are based on projected
deposition rates for "wet" areas of the U.S. as given in Table 4.
The levels of cesium-137 were taken to be 1.7 times the level of
strontium-90. Estimates of the possible contributions from short-
lived nuclides were based on an apparent age of fission debris in
the stratosphere corresponding to a mean production time of mid-
September 1962, and the estimated levels of these nuclides relative
to strontium-90 at the time of deposition. The estimated doses
were then calculated, making corrections for weathering, shield-
ing, and the movement of different radionuclides through the en-
vironment to man.
5.3 The period of the test moratorium from 1959 to 1961 was
sufficient for a peak level of radionuclides such as strontium-90
and cesium-137 to occur and for subsequent downward trends in
levels of these radionuclides to be established. The period was
not sufficient to define the effective rates of removal of these radio-
nuclides from the biosphere in the absence of deposition of addi-
tional fallout. The effective half-times in the environment for
these radionuclides and their biological availability are, therefore,
subject to uncertainty, and dose estimates in this report should be
considered in that light.
5.4 Whole body and reproductive cell doses from both short-
lived and long-lived radionuclides from 1962 tests were considered
to begin during 1962. External exposures from cesium-137 were
assumed to diminish with an effective halftime of ten years.
Exposures to external short-lived radionuclides and short-lived in-
ternal emitters such as strontium-89 and barium-140—lanthanum-
140 were considered to be completed within about one year fol-
lowing the 1962 tests.
5.5 Strontium-90 is expected to be effectively removed from that
part of the biosphere which is important to man with an effective
half-time of ten years. Therefore, doses for bone and bone mar-
row from 1962 tests were predicted for infants born in 1963 since
this is the most sensitive age group and is expected to have the
maximum concentration of strontium-90 per gram of calcium as
discussed in Section IV of this report. Similarly, this is the age
group expected to receive the highest lifetime bone dose from tests
conducted in 1962.
5.6 The whole-body and bone doses to people deriving their
foodstuffs from "dry" areas of the U.S. are estimated to be some-
what less (possibly as much as one-third to one-half) than those
deriving their food from "wet" areas. Individuals and population
groups subsisting on diets differing greatly from the diet typical
of the majority of the population in "wet" and "dry" areas of the
-------
1122 LEGAL COMPILATION—RADIATION
U.S. are expected to receive doses both higher and lower than the
average dose for the "wet" area presented in Table 12. Although
some individuals in the U.S. will receive doses higher than for
"wet" areas and some will receive doses lower than for "dry"
areas, it is expected that doses differing from these average values
by more than a factor of 10 will not occur.
5.7 For calculations of 30-year and 70-year doses, exposure to
carbon-14 from 1962 tests of 217 MT total yield (Table 2) was
assumed to be reduced with a mean time of 48 years (see Glos-
sary), or a half-time of 33 years. Since the total yields of tests
conducted in 1962 are about two-thirds of the total yield from
tests conducted through 1961, the long-term doses from carbon-14
from 1962 tests will be almost the same as the long-term doses
from carbon-14 discussed in FRC Report No. 3.
[p. 21]
Doses from all Tests through 1962
5.8 Estimates of doses to people in the U.S. in "wet" areas from
exposure to fallout radioactivity produced by all nuclear tests con-
ducted through 1962 are presented in Table 13. These estimates
are based upon observed levels of deposited radioactivity and ob-
served levels of radioactivity in people for "wet" areas through
1962 and upon annual deposition levels of radioactivity expected
to occur in "wet" areas through 1965.
5.9 Whole-body and reproductive cell doses from both short-
lived and long-lived radionuclides produced by all tests were esti-
mated for population in the U.S. born prior to beginning of nuclear
testing. These doses are assumed to be independent of age groups
within the population. Based primarily upon measurements of
radioactivity in 1961 and 1962, 30-year and 70-year doses related
to tests through 1961 are now estimated to closely approximate
the lower number of the range of estimated values for whole-body
and reproductive cells presented in Table I of FRC Report No. 3
(30-year, whole body and reproductive cells both 60 millirems; 70-
year, whole-body and reproductive cells both 70 millirems;). The
estimates of whole-body and reproductive cell doses for all tests
through 1962 in Table 13 of the current report will be found to be
the sum of whole-body doses from all tests through 1961 (shown in
Col. 1 of Table 13), plus the estimated whole-body and reproduc-
tive cell doses from 1962 tests presented in Table 12, and repeated
as Col. 2 in Table 13.
5.10 The doses to bone and bone marrow from all tests through
1962, presented in Table 13, will not be the sum of estimated bone
doses in FRC Report No. 3 (Col. 1 of Table 13) plus doses from
-------
GUIDELINES AND REPORTS 1123
1962 tests in Table 12 of this report. The doses to bone and bone
marrow were estimated for the age group in the population ex-
pected to receive the highest doses from all tests through 1962.
The age group considered was infants born in 1963. This deter-
mination was based upon a review of measured values of stron-
tium-90 in human bone samples obtained from the beginning of
testing through the first six months in 1962, predicted levels in
new bone and bone being re-formed or exchanged metabolically
from 1963 through 1965, the whole body doses for infants born
during various years since testing began.
5.11 Doses to bone and bone marrow in Table 13 are very little
higher than those estimated for tests through 1961 and presented
in Table I of FRC Report No. 3. The reason for such results is
that measured levels of strontium-90 deposition were less in 1962
than had been predicted.
5.12 Doses to bone and bone marrow for the adult population
in the U.S. are expected to be smaller than the doses to the most
sensitive age group of children.
5.13 Doses to people in "dry" areas of the U.S. from all tests
through 1962 are estimated to be about one-third to one-half those
for people in "wet" areas. The lower deposition levels in the "dry"
areas reduce the exposure from sources external to the body, and
lower the concentrations of radionuclides in locally produced food.
5.14 Thirty-year and 70-year carbon-14 doses from tests
through 1962 were estimated using a total yield of 459 MT ', a
production rate of 2 X 102" atoms carbon-14 per MT total yield,
and a dose rate of 1 millirem per year for naturally occurring
carbon-14. The exposure from carbon-14 was assumed to be re-
duced with a mean time of 48 years, the time calculated for ex-
change between the atmosphere and the vast carbon reservoir in
the oceans.
5.15 It was estimated in FRC Report No. 3 that carbon-14 from
weapons testing conducted through 1961 would lead to an average
per capita whole-body and reproductive cell dose of 10 to 15 milli-
rems in the first thirty years. This was estimated to equilibrate
eventually at a level of about 0.75 millirem per generation, and this
would continue for hundreds of generations. Since testing con-
ducted in 1962 contributed almost an equal amount of carbon-14,
the above values may be doubled to arrive at the long-term doses
that are now predicted.
[p. 22]
1 Based on the sum of the total yields for air detonations and one-half the total yields of surface
detonations from Table 1 of this lepoit.
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1124 LEGAL COMPILATION—RADIATION
Thyroid Doses from Iodine-131
5.16 Doses to the thyroid due to iodine-131 in fallout have oc-
curred during and immediately following periods of nuclear test-
ing. The Public Health Service's Pasteurized Milk Network re-
ported no iodine-131 at detectable levels in the interval from 1959
through August 1961. Table 10 shows that following resumption
of nuclear testing in September 1961, iodine-131 was found gen-
erally throughout the nation in zones of both high and low pre-
cipitation. Limited in vivo measurements in the fall of 1961 and
in 1962 support a conclusion that fresh milk is the principal source
of iodine-131 exposure to the thyroid gland in a large proportion of
the population.
5.17 The relationship between iodine-131 intake and thyroid
dose is based on the biological model derived in FRC Report No. 2.
An estimated annual average daily intake of 80 2 picocuries of
iodine-131 would result in an average dose of 500 millirems in one
year to a suitable sample of exposed infants in which the thyroid
weight is taken as two grams. This condition applied approxi-
mately to the age group from 6 to 18 months. With children above
approximately 18 months of age the dose to the thyroid would
become progressively smaller with the increase in size of the thy-
roid to a value in the adult of approximately one-tenth the value
in infants.
5.18 Estimates of iodine-131 dose to the thyroid developed for
infants 6 to 18 months of age on the basis of the above relation-
ship between intake and dose, assuming one liter of fresh milk
consumption per day, ranged from 30 to 440 millirems in 1961 and
from 30 to 650 millirems in 1962. These values are estimates of
thyroid dose for high and low individual stations in the pasteurized
milk network for the years indicated. It has been estimated that a
small number of infants in localized areas conceivably could re-
ceive doses from 10 to 30 times the average.
[p. 23]
2 "Using the known factors and the assumptions enumerated above, it can be calculated that an
average daily intake of 80 micromicrocuries of iodine-131 per day would meet the RPG for the
thyroid for averages of suitable samples of an exposed population group of 0.5 rem per year.
As stated in Section I, it is appropriate to specify three ranges of transient rates of daily intake
in order to provide guidance for the Federal agencies in the establishment of operating criteria.
For this purpose, the value of 80 micromiciocuries per day has been rounded off to 100 micro-
microcuries per day as being more in keeping with the precision of the data." (Paragraph 2.14,
FRC Report No. 2).
-------
GUIDELINES AND REPORTS
1125
TABLE 12.—ESTIMATED RADIATION DOSES IN THE "WET" AREAS FROM TESTING CONDUCTED IN 1962
[Doses expressed in millirem.)
Radiation doses
Tissue or organ
30-year
70-year
Whole body and reproductive cells:
Cesium-137 external
Cesium-137 internal
Short-lived nuchdes
Carbon-14
Total
Bone:
Strontium-90
Strontium-89
Whole body
Total
Bone marrow:
Strontium-90
Strontium-89
Whole body
Total
9
9
18
11
10
10
18
18
47
56
180
39
56
"275
60
13
56
"129
TABLE 13.—ESTIMATED RADIATION DOSES IN THE "WET" AREAS OF THE U.S. FROM
ALL NUCLEAR WEAPONS TESTING CONDUCTED THROUGH 1962
[Doses expressed in millirem.]
From tests From tests From all tests From
Tissue or organ conducted conducted conducted natural
through 1961 ' in 1962 through 1962 background
Whole body and reproductive cells:
1 year . . . . .
Bone:
1 year
70 years
Bone marrow:
1 year
70 years
. . 10-25
60-130
70-150
30-80
400-900
20-40
150-350
24
47
56
83
275
44
130
2 110
* 130
"465
J«215
3,000
7 000
9 100
7,000
1 Taken from Table 1, FRC No. 3. Based on surveillance measurements made in 1962, the actual ex-
posures are expected to correspond to the low end of the reported range. Actual exposures to bone and
bone marrow are now expected to be even lower than the reported range.
2 The whole body dose is based on the average person receiving the highest exposure assuming that the
person was born prior to the beginning of testing. Current estimates indicate that from tests conducted
through 1961, the whole body and reproductive cell doses for 30 and 70 years will be 63 and 74 miihrems
respectively.
3 The bone and bone marrow doses are calculated for the average person born in 1963 since it is believed
that this person might receive the highest bone dose of any age group.
4 Doses in previous columns are not additive; see paragraph 5.10.
[p. 24]
-------
1126 LEGAL COMPILATION—EADIATION
SECTION VI
EVALUATION
6.1 The Federal Radiation Council reported on the health im-
plications of fallout from nuclear weapons testing through 1961
in FRC Report No. 3, issued in May 1962. (Copy attached) The
doses were evaluated by comparison with the doses due to nat-
urally occurring sources of radiation following the procedures
developed over the past several years through studies conducted
by the National Academy of Sciences, the United Nations Scien-
tific Committee on the Effects of Atomic Radiation, the National
Committee on Radiation Protection and Measurements, the Inter-
national Commission on Radiological Protection, and the fallout
prediction panels convened by the Joint Committee on Atomic
Energy in 1957, 1959, and 1962. Two types of biological effects
are of concern; effects induced by exposure of the reproductive
cells (genetic effects), and possible effects on persons now living
(somatic effects) resulting from the exposure. Both types of ef-
fects have been considered and evaluated by the National Academy
of Sciences Committee on the Biological Effects of Atomic Radia-
tion and the conclusions of this committee have been accepted by
the Federal Radiation Council as the basis for the scientific aspects
of the present evaluation.
6.2 The genetics subcommittee of the National Academy of Sci-
ences Committee on the Biological Effects of Atomic Radiation has
recommended that the genetically effective per capita dose during
the first thirty years of life be limited to 10 Roentgens (equivalent
to 10,000 millirems as used in this report) from all man-made
sources, including medical exposures.
6.3 The revised estimates of the short-term per capita effective
dose to the reproductive cells show that weapons tests conducted
during 1962 will be about 47 millirems. All tests conducted
through December 1962 will result in a per capita 30-year dose of
about 110 millirems. This is about one-hundredth of the amount
recommended by the National Academy of Sciences. These values
are considerably less than the corresponding 30-year dose of 3,000
millirems from naturally occurring sources during the same pe-
riod. Similarly, the variations in dose-rate from worldwide fall-
out in different parts of the country are less than the variations in
dose-rate from naturally occurring sources in the inhabited parts
of the world. Further, comparison with the 5,000 millirems per
generation proposed previously by the Federal Radiation Council
as a level of genetic risk that would be acceptable to gain the
benefits of nuclear energy from normal peacetime operations and
-------
GUIDELINES AND REPORTS 1127
the 10,000 millirems per generation recommended by the NAS
Subcommittee on Genetics as a "reasonable quota" for man-made
radiation exposure of the general public indicates that present and
anticipated levels of fallout do not constitute an undue risk to the
genetic future of the nation.
6.4 The genetically significant dose per generation attributable
to tests conducted through 1962 will be greatly reduced in later
generations. The total dose which may come eventually from ma-
terial still in the stratosphere in 1966 plus the long-term effects
from carbon-14 may be somewhat larger than the estimates re-
ported. Thus, the ultimate genetic effects attributable to weapons
tests conducted in 1962 are expected to be nearly as much as that
from all tests conducted prior to 1962.
6.5 In addition to the possible influence of weapons testing on
heredity, the possibility of adverse health effects on persons now
living is of concern to the Council. The estimates in Table 13 show
that testing conducted through 1962 is expected to result in cumu-
lative whole-body doses over a 70-year period from radionuclides
external to the body and radionuclides in the body of about 130
millirems. The biological effect of concern is the induction of
serious diseases such as cancer that might result from irradiation
of the whole body.
6.6 The Subcommittee on Pathological Effects of the National
Academy of Sciences Committees on the Biological Effects of
Atomic Radiation (1960) concluded that as long as the criteria
for the effective genetic exposure were met, any possible effects on
the health of the persons exposed would be much too small to be
perceptible. However, the special cases of iodine-131 and stron-
tium-90 which deposit preferentially in the thyroid and bone
respectively were pointed out as possible exceptions to the evalu-
ation. The Council, therefore, concludes that except for iodine-131
and strontium-90, the estimated whole-body doses from present
and anticipated levels of fallout do not constitute an undue risk
in terms of direct effects on the individuals exposed.
[p. 25]
Evaluation of Iodine-131
6.7 The special case of iodine-131 has been recognized by the
Federal Radiation Council. The known experience in the U.S. re-
lated to iodine-131 in milk from 1959 to the present is summarized
in Table 10. The data are reported in terms of the average daily
intake of iodine-131 over a 12-month period assuming a consump-
tion of 1 liter of milk per day to correspond to the cumulative levels
-------
1128 LEGAL COMPILATION—RADIATION
of iodine-131 actually observed at the regular milk sampling sta-
tions. The corresponding radiation dose for the average infant
thyroid in the highest region has a calculated value of 620 milli-
rems. In the special case where nearly all of the annual intake
could come from exposure to abnormally high concentrations in a
local area, resulting from a single nuclear explosion of low yield,
the Council recognized that some small number of individual in-
fants could conceivably receive doses 10 to 30 times the average
for the area as a whole.
6.8 Based on the advice of a special panel convened by the Coun-
cil in the summer of 1962, it was concluded that radiation doses to
the thyroid many times higher than those provided in FRC Report
No. 2 would not result in a detectable increase in diseases such as
thyroid cancer. No case of thyroid cancer in man ascribable to
radioactive iodine used in the medical diagnosis and treatment of
thyroid disease has yet been established. The radiation doses
administered for diagnosis and treatment of thyroid disorders
have ranged up to thousands of times higher than the 1.5 rems per
year recommended as a Radiation Protection Guide in FRC Report
No. 2 for exposure to individuals due to iodine-131 released to the
environment from normal peacetime operations.
6.9 The Council concluded in September 1962 that iodine-131
exposures at the levels existing then, involve health risks so slight
that countermeasures applied to the food industries might have an
adverse, rather than favorable effect on public well-being. It is
similarly concluded in this report that iodine-131 doses from
weapons testing conducted through 1962 have not caused an undue
risk to health.
Evaluation of Strontium-90
6.10 The health risk from strontium-90 arises from the fact that
it is taken into the body with calcium and is deposited in the skele-
ton. Once incorporated into the skeleton, it causes radiation doses
to the skeleton at a continuously decreasing rate during the entire
life of the individual. The lifetime doses to the age group receiv-
ing the highest doses from radionuclides in fallout are expected to
be about 465 millirems for bone and 215 millirems for bone mar-
row, Of this exposure, it is estimated that the average concen-
tration of strontium-90 in new bone at its maximum value from
fallout associated with all weapons testing conducted through 1962
may reach about 12 picocuries strontium-90 per gram of calcium,
although by metabolic activity this would soon drop to an average
concentration in the whole skeleton of about 7 picocuries per gram
of calcium. This would give an initial dose rate to new bone of
-------
GUIDELINES AND REPORTS 1129
36 millirems per year and to bone marrow of 12 millirems per year.
When redistributed, the dose rates would be 21 millirems per year
to bone, and 7 millirems per year to bone marrow.
6.11 The Council has evaluated the possible need and desirabil-
ity of instituting national programs for modifying the diet, remov-
ing strontium-90 from food supplies such as milk, or otherwise
limiting the annual intake of strontium-90. A general apprecia-
tion of the contribution of strontium-90 to health risks can be
gained by comparing the lifetime radiation dose of 465 millirems
to bone with the corresponding dose of 9,100 millirems from nat-
ural sources; the radiation dose of 215 millirems to bone marrow
with the corresponding dose of 7,000 millirems from natural
sources.
6.12 With specific reference to strontium-90, the Council has re-
examined its recommendations for skeletal burdens of strontium-
90 which have been judged to be an acceptable risk to gain the ben-
efits of normal peacetime operations. The selection of these
skeletal burdens reflect the simultaneous judgment that the corre-
sponding risks to health are too small to warrant actions that
would interfere with or disrupt the normal utilization of food.
The skeletal burden of strontium-90 corresponding to the Radia-
tion Protection Guide recommended in FRC Report No. 2 for limit-
ing the exposure of the skeleton is 150 picocuries of strontium-90
per gram of calcium. However, since no operating need for ex-
posures this high was foreseen, the recommended level was re-
duced to 50 picocuries of strontium-90 per gram of calcium,
corresponding to a sustained dietary intake of 200 picocuries of
strontium-90 per day. The skeletal burdens of strontium-90 from
present and anticipated levels of fallout are well below these
values.
6.13 On the basis of the preceding considerations, it is concluded
that the health risks from present and anticipated levels of stron-
tium-90 from fallout due to testing through 1962 are too small to
justify measures to limit the intake by modification of the diet or
altering the normal distribution and use of food. It is further con-
cluded that since milk and dairy products are the major sources of
calcium in the U.S. diet and since these products have a lower con-
centration of strontium-90 in relation to calcium than the total diet,
restriction or reduction in the normal use of these food products
would be unwise.
[P. 26]
Future Indications
6.14 Looking into the future, the Council notes that the highest
-------
1130 LEGAL COMPILATION—RADIATION
annual dose rates have been associated with the short-lived radio-
nuclides and tropospheric fallout. How much these annual trans-
ients contribute to the cumulative lifetime exposures depends, of
course, on the frequency with which test programs occur. This
review has shown that the testing programs of 1961 and 1962
reached higher levels of fission and total yields than any previous
comparable period, and the radionuclides associated with tropo-
spheric fallout were correspondingly evident.
6.15 Renewed attention has been directed to the special case of
iodine-131, and the pathways by which it passes through the en-
vironment to man. Studies conducted by the Department of Ag-
riculture and the U.S. Public Health Service in 1962 have
demonstrated the effectiveness of reducing the iodine-131 levels in
milk by adjusting the source of feed used by the dairy cattle if
such action is needed. Also, the Atomic Energy Commission has
recently initiated a program at the Livermore Radiation Lab-
oratory to gain a better understanding of the processes affecting
the distribution of fallout and its movement through the environ-
ment. Iodine-131 is included among the nuclides of interest to
this program.
6.16 As to long-lived radionuclides such as strontium-90 the
Council notes that processes for the removal of radionuclides from
milk developed jointly by the Department of Agriculture, the Pub-
lic Health Service, and the Atomic Energy Commission are now
being evaluated for the feasibility of full-scale production for pos-
sible use in an emergency.
6.17 However, in the Council's judgment, major national pro-
grams directed at removing strontium-90 from food supplies would
not contribute to the national welfare at present or projected levels
of strontium-90. Even if the strontium-90 levels in human bone
reached those corresponding to the Radiation Protection Guide
established for the control of normal peacetime operations, the re-
moval of strontium-90 from foods would not necessarily be in the
best interests of the nation. The Council would have to consider
whether the health risk would be great enough to justify the total
impact of such a program on the economy and the necessary al-
location of national resources in relation to the health benefits that
might be achieved through feasible reduction in strontium-90
intake.
[p. 27]
GLOSSARY OF TERMS
Absorbed Dose.—The energy imparted to matter by ionizing radiation per unit
mass of irradiated material at the place of interest.
-------
GUIDELINES AND REPORTS 1131
Activity. The number of disintegrations of a quantity of radionuclide per
unit time.
Average Dose. The arithmetic mean radiation dose. The average may be
taken with respect to time, number of people, location, or the dose distribu-
tion in tissue.
Beta Radiation. Swiftly moving electrons emitted by radioactive substances.
Strontium-90, strontium-89, and carbon-14 all emit beta particles.
Biological Half-life. The time taken for the body burden of a radionuclide to
be reduced by biological removal processes to one-half its initial value.
Radioactive decay is not involved.
Body Burden. The amount of a specified radioactive material or the summa-
tion of the amounts of various radioactive materials in a person's body at
the time of interest.
Critical Organ. An organ or tissue most affected by ionizing radiations from
the deposition of a specified internal emitter or from external sources. The
reproductive cells are considered the critical tissue for genetic effects. The
thyroid is considered the critical organ for the effects from radioactive iodine.
Bone and bone marrow are considered the critical organs for the effects from
strontium-90.
Curie. A measure of the activity (rate of disintegration or decay) of a radio-
active substance. One curie equals 3.7 x 101" nuclear disintegrations per
second, or 2.2 x 1012 per minute.
Megacurie (MC).—One million curies. A fission yield of 10 megatons creates
approximately 1 megacurie of strontium-90.
Millicurie (me). One-thousandth of a curie. Also one thousand microcuries.
Microcurie (/ic). One-millionth of a curie.
Picocurie (pc). One micromicrocurie (^c). This is one-millionth of a micro-
curie or one-millionth-millionth of a curie. It corresponds to a rate of radio-
active decay equivalent to 2.2 disintegrations per minute.
Dose. A measure of the energy absorbed in tissue by the action of ionizing
radiation on tissue. As used in radiation protection, definitive practice re-
quires that the term be used in such combining forms as radiation dose,
absorbed dose, whole-body dose, and partial-body dose.
Dose-effect Relationship. The magnitude of a specific biological effect, ex-
pressed as a function of the radiation dose producing it. It is frequently
represented as a curve described as a dose-effect curve, dose-effect response
curve, or dose response curve.
Dose Equivalent. A concept used in radiation-protection work to permit the
summation of doses from radiations having varying linear energy transfers,
distributions of dose, etc. It is equal numerically to the product of absorbed
dose in rads and arbitrarily defined quality factors, dose distribution factors
and other necessary modifying factors. In the case of mixed radiations, the
dose equivalent is assumed to be equal to the sum of the products of the
absorbed dose of each radiation and its factors.
Effective Half-life or Half-time. The time taken for the total number of atoms
of a radioactive nuclide to be reduced to one-half of its initial value by com-
bined radioactive decay and biological removal processes.
Environment. The physical environment of the world we live in consisting of
the atmosphere, the hydrosphere, and the lithosphere. The biosphere is that
part of the environment supporting life and which is important to man.
Exposure. A measure of x and gamma radiation at a point. However, it is
often used in the sense of being made subject to the action of radiation.
-------
1132 LEGAL COMPILATION—RADIATION
External Exposure. The exposure of body tissues to ionizing radiation origi-
nating from sources outside the body.
[p. 28]
Fallout. The process of phenomenon of the fallback to the earth's surface of
particles contaminated with radioactive material from the radioactive cloud.
The term is also applied in a collective sense to the contaminated particulate
matter itself. The early (or local) fallout is defined, somewhat arbitrarily,
as those particles which reach the earth within 24 hours after a nuclear
explosion. The delayed (or worldwide) fallout consists of the smaller par-
ticles which ascend into the upper troposphere and into the stratosphere and
are carried by the winds to all parts of the earth. The delayed fallout is
brought to earth, mainly by rain and snow, over extended periods ranging
from months to years.
Internal Exposure. The exposure of body tissue to ionizing radiations origi-
nating from radionuclides contained within the body.
Whole-body Exposure. Literally, the exposure of the whole body.
Fission. The process whereby the nucleus of the particular heavy element
splits into (generally) 2 nuclei of lighter elements, with the release of sub-
stantial amounts of energy. The most important fissionable materials are
uranium-235 and plutonium-239.
Fission Products. A general term for the complex mixture of substances pro-
duced as the result of nuclear fission. Something like 80 different fission
fragments result from approximately 40 different modes of fission of a given
nuclear species. The fission fragments, being radioactive, immediately begin
to decay, forming additional radioactive products with the result that the
complex mixture of fission products so formed contains about 200 different
isotopes of 36 elements. For example, iodine-131, being a daughter element
with several preceding radioactive parents, reaches its maximum production
approximately 7 hours after the detonation of a fission device.
Fission Yield. The equivalent energy released as the result of nuclear fission.
The production of fission products is proportional to the fission yield.
Fusion. The process whereby the nuclei of light elements, especially those of
the isotopes of hydrogen, combine to form the nucleus of a heavier element
with the release of substantial amounts of energy. These are so called
thermonuclear reactions because very high temperatures are used to bring
about the fusion of the light nuclei. Neutrons, leading to the production of
carbon-14, are produced by this reaction; however, fission products are not.
Gamma Rays. Electromagnetic waves of very short wave lengths produced
during the disintegration of radioactive elements. Like x-rays, they readily
penetrate body tissues.
Genetic Effect. A change in a reproductive cell which would alter the char-
acteristics of an individual produced from the affected cell or which causes a
mutation that may be inheritable by subsequent generations.
Half-life. The time required for the activity (the disintegration rate) of a
radioactive nuclide to decay to one-half of the initial value.
Internal Emitters. Radionuclides contained within the human body.
Isotopes. Atoms of the same element, i.e., having the same atomic number, but
of differing atomic weights. The isotopes of an element have closely similar
chemical and physical properties, but different in atomic mass (due to dif-
ferent numbers of neutrons in the atomic nuclei) and in their nuclear
properties (e.g., stable, radioactive, fissionable, etc.). Nearly all elements
found in nature are mixtures of several isotopes. (See nuclide)
-------
GUIDELINES AND REPORTS 1133
Mean or Average-lifetime. A particular radioactive atom can decay now,
later, or never. However, the average or mean-life expectancy of a number
of the same radionuclides is a definite quantity and is equal to 1.4 times the
half-life. Analogous terms are often used to express changes in radio-
nuclide concentrations in different compartments of the environment as a
function of time. For example, the rate of disappearance of carbon-14 from
the atmosphere as the result of diffusion into the ocean, the biosphere, and
other environmental compartments has been expressed in terms of a half-
time of 33 years and a meantime of 48 years.
Megaton Yield. A nuclear detonation which releases a total energy equivalent
to one million tons of TNT.
Natural Background Radiation. Ionizing radiations from naturally occurring
radionuclides as they exist in nature plus cosmic radiation.
[p. 29]
Normal Peacetime Operations. The peaceful applications of nuclear tech-
nology where the primary radiation protection control is placed on the design
and use of the source.
Nuclide. An atom of a particular species or element; that is, characterized
by an atomic number and an atomic weight. Carbon-14 is a nuclide. Carbon
as it occurs naturally consists of 3 nuclides; carbon-12, carbon-13, and
carbon-14, which together bear the relationship of isotopes.
Organ or Tissue Dose. The radiation dose received by a particular body organ
or tissue. The radiation may be from an external or an internal source.
Population Dose.—The radiation dose received by members of a population. It
is usually estimated as that dose which would be received by the average
member of the population under consideration.
Radiation Effect.—A response or change induced by exposure to ionizing
radiation.
Radiation (Ionizing). Radiation capable of producing ions in a medium, par-
ticularly tissues of the human body. Examples are x-radiation and gamma
radiation, beta radiation, and cosmic radiation.
Radiation Protection Guide (RPG). The radiation dose which should not be
exceeded without careful consideration of the reasons for doing so; every
effort should be made to encourage the maintenance of radiation doses as far
below this guide as practicable.
Radioactivity. The property or process whereby certain isotopes or nuclides
spontaneously disintegrate emitting particles and/or gamma rays by the
disintegration of the atomic nuclei. (See activity)
Radiinuclide. A radioactive nuclide.
Rem. A special unit of dose equivalent. It is that quantity of any type of
ionizing radiation which, when absorbed in the human body, produces an
effect equivalent to the absorption of 1 roentgen of x or gamma radiation at
a given energy.
Seventy-year Somatic Dose. That whole-body dose received by tissues other
than the reproductive cells over a period of 70 years. When calculated for
exposures from fallout this dose includes contributions from whole-body
radiation from external sources, cesium-137 taken internally, and carbon-14.
Somatic Effect. A change (other than genetic) produced in any tissue which
alters the normal body processes of the irradiated individual.
Stratosphere. A relatively stable layer of the atmosphere lying above the
tropopause. For the purpose of this document, the lower stratosphere is
-------
1134 LEGAL COMPILATION—RADIATION
defined as the first few tens of thousands of feet above the tropopause and
the upper stratosphere as the layer to about 150,000 feet.
Stratospheric Fallout. Fallout associated with weapon debris which was
initially injected above the troposphere into the stratosphere. This is the
component that results in world-wide distribution of fallout from the testing
of nuclear weapons.
Strontium Unit (SU). One picocurie of strontium-90 per gram of calcium,
usually in bone but now extended to items of food and milk.
Thirty-year Genetic Dose. The dose estimated to be received from all sources
by the reproductive tissues for a period of 30 years. When computed for
fallout exposures this includes whole-body doses from external sources,
gamma radiation from cesium-137 in the body, and carbon-14. Recent re-
ports indicate that strontium-90 may also be a minor contributor.
Tropopause. The boundary between the troposphere and the stratosphere. It
normally occurs at an altitude of about 30,000 to 40,000 feet in polar and
temperature regions and about 55,000 feet in the tropical and equatorial
regions.
Troposphere. That portion of the atmosphere below the stratosphere. It is
that portion in which temperature generally decreases rapidly with altitude,
clouds form, and which is associated with all of what we generally know as
"weather." The altitude of the troposphere varies from the equator to the
poles and from winter to summer.
[p. 30]
Tropospheric Fallout. The deposition of radioactive weapons debris which was
initially injected into the troposphere and not deposited as local fallout.
Yield. The total effective energy released in the nuclear explosion. It is
usually expressed in terms of the equivalent tonnage of TNT required to pro-
duce the same energy release in an explosion.
[p. 31]
4.1e BACKGROUND MATERIAL FOR THE DEVELOPMENT
OF RADIATION PROTECTION STANDARDS, REPORT NO. 5,
STAFF REPORT OF THE FEDERAL RADIATION COUNCIL,
JULY, 1964.
CONTENTS
[P- 23]
Section
I. Introduction 1
II. Origin and Distribution of Radioactive Contamination 4
III. Protective Actions and Their Applications 7
IV. Guidance Applicable to Iodine-131 11
[p. iii]
SECTION I
INTRODUCTION
This report contains background material used in the develop-
ment of guidance for Federal agencies in respect to: (1) plan-
-------
GUIDELINES AND REPORTS 1135
ning protective actions to reduce potential doses to the population
from radioactive fisson products which may gain access to food,
and (2) doses at which implementation of protective actions may
be appropriate.
The material is directed to guidance concerned with protective
actions affecting the normal production, processing, distribution,
and use of food for human consumption when the action is taken
because of the radioactive content of the food.
The first two reports of the Federal Radiation Council con-
tained background material used in the development of guidance
given in the Memorandums approved by the President on May 13,
1960, and September 13, 1961. These reports provided a general
philosophy of radiation protection and general principles of con-
trol based on the annual intake of radioactive materials. The
recommendations contained therein were intended to provide the
basis for the control and regulation of normal peacetime opera-
tions in which exposure to radiation is a factor. Numerical values
for the Radiation Protection Guides designed to limit the ex-
posure of the whole body and certain organs as the result of
normal peacetime operations were provided.
During the period of atmospheric testing of nuclear weapons in
1961 and 1962 the question arose as to the possible need for pro-
tective actions and the use of existing Radiation Protection Guides
for determining the conditions under which the production, pro-
cessing, distribution, and use of food, particularly fresh fluid milk,
should be altered to reduce human intake of radioactive materials
from fallout.
In September 1962 the Federal Radiation Council stated, in ef-
fect, that the Radiation Protection Guides provided for the con-
duct of normal peacetime operations are not intended to set a
limit at which protective action affecting the normal production,
processing, distribution, and use of food should be taken, nor to
indicate what kind of action should be taken. In the 1963 hear-
ings, "Fallout, Radiation Standards, and Countermeasures," con-
ducted by the Joint Committee on Atomic Energy, the Council
reiterated that position and noted that it would recommend to
the President guidance for the appropriate Federal agencies ap-
plicable to a determination of the need for protective actions.
Scope
Limiting the exposure of members of the population to man-
made radioactive material can be accomplished by controlling the
release of such material from its place of origin or use, or by pro-
tecting the population after the material is released to the environ-
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1136 LEGAL COMPILATION—RADIATION
ment. This report is directed to guidance for protecting the
[p. 1]
population from radioactive material after it has been released to
the environment in concentrations which justify action.
Situations justifying protective action could occur from such
events as: (1) an industrial accident, possibly involving a nuclear
reactor or a nuclear fuel processing plant, and (2) release of
radioactive materials from the detonation of nuclear weapons or
other nuclear devices.
The guidance concerns protective actions which might be ap-
plied to the production, processing, distribution, or use of food to
reduce the potential human intake of such radioactive material.
This guidance is confined in application to those conditions under
which the hazard of concern is that associated with the ingestion
of radioactive materials. Conditions requiring protection from
external gamma radiation or protection when inhalation may also
be a significant mode of entry for radioactive material into the
human body involve different considerations.
This report includes guidance as to the general principles con-
cerned with protective actions and specific guidance applicable to
iodine-131.
Preparation of the Staff Report
In the development of this report, the Staff has reviewed the
literature on the origin, distribution, mechanisms of transmission
through the environment, and potential biological effects of radio-
active materials. In particular, the Staff has studied the tran-
scripts of the hearings conducted by the Joint Committee on
Atomic Energy; the reports by the National Committee on Radia-
tion Protection and Measurements, the World Health Organization
and Food and Agricultural Organization of the United Nations,
the United Kingdom Medical Research Council's Committee on
Protection against Ionizing Radiations, the National Advisory
Committee on Radiation—an advisory committee to the Surgeon
General, United States Public Health Service; and the "Proceed-
ings of the Hanford Symposium on the Biology of Radioiodine."
The Staff also has had considerable assistance from many in-
dividual scientists and technical experts.
Definitions
The absorbed dose is the energy imparted to a volume of ir-
radiated material per unit mass of that volume.
The md is a unit of absorbed dose equal to 100 ergs per gram.
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GUIDELINES AND REPORTS 1137
The projected dose is the dose that would be received in the
future by individuals in the population group from the con-
taminating event if no protective action were taken.
[p. 2]
The Protective Action Guide (PAG) is the projected absorbed
dose to individuals in the general population which warrants pro-
tective action following a contaminating event.
The curie is a unit of radioactivity denned as 3.7 X 1010 trans-
formations per second. Commonly used multiples of the curie are
the following:
1 millicurie = 1 X 10 ~3 curie
1 microcurie = 1 X 10 ~6 curie
1 nanocurie = 1 X 10 ~9 curie
1 picocurie = 1 micromicrocurie = 1 X 10 ~12 curie
[p. 3]
SECTION II
ORIGIN AND DISTRIBUTION OF RADIOACTIVE CONTAMINATION
The origin and distribution of radioactive material injected into
the atmosphere and its transport mechanisms through the en-
vironment to man have been studied intensively both nationally
and internationally for the past decade in connection with the at-
mospheric testing of nuclear weapons. The past and anticipated
concentrations of radioactive materials in the environment from
weapons testing through 1962 have been studied and evaluated by
the Council in its Reports No. 3 and No. 4.
Material injected into the stratosphere by nuclear weapons tests
eventually descends to the troposphere from which it is deposited
on the earth's surface. During storage in the stratosphere, short-
lived radionuclides decay essentially to zero. Long-lived radionu-
clides which find their way to the troposphere deposit relatively
uniformly on a regional basis, although the quantities vary with
latitude and with rainfall. A somewhat similar distribution pat-
tern of short-lived radioactive material such as iodine-131 has been
observed in the U.S. for the tropospheric distribution of debris
from tests conducted outside the U.S.
When radioactive material is released to the atmosphere at
ground level, as would generally be the case in an industrial ac-
cident, diffusion in the troposphere is limited and the passage of
the radioactive cloud over an area takes a relatively short time.
However, the concentrations in the cloud can be high. The deposi-
tion of radioactive materials in this case can lead to possible rad-
iation doses that warrant protective action.
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1138 LEGAL COMPILATION—RADIATION
Radioactive Nuclides of Interest
Although nuclear fission results in many nuclides, most of which
are radioactive, their chemical and physical properties are such
that few of them are of interest as potential radioactive contam-
inants of food. Some of these radionuclides have such short radio-
active half-lives that their radioactive decay to stable nuclides is
complete before the food is consumed. Those of principal interest
are isotopes of chemical elements readily utilized by vegetation or
animals, and of sufficiently long radioactive half-lives that much
of their radioactivity will not have disappeared before they have
reached the human diet.
The relative importance of different radionuclides may depend
on many factors such as the time that elapses between fission and
the release of fission products to the environment, chemical or
physical separation or fractionation, conditions of release, and
season of year. For example, in unseparated fission products only
a few days of age, the properties of iodine make it the critical
radionuclide, while a few weeks later the disappearance of iodine-
131 will leave the longer-lived strontium-89, strontium-90, and
[p. 4]
cesium-137 as the nuclides of interest. Many studies of possible
types of release important to this report have led to the conclusion
that events requiring protective actions are most likely to involve
iodine-131 as the critical nuclide.
The Transmission Chain
The path of radioactive material from the atmosphere through
the food chain to man is shown in Figure I. The material is
scavenged from the atmosphere by meteorological processes, par-
ticularly rain. If the air mass containing the radioactive material
is at ground level the radionuclides may be directly removed from
the air by vegetation. Following the initial deposition, the radio-
active contamination tends to be removed by various processes,
such as being washed off by subsequent rainfall or being blown off
by the wind. The extent to which such removal occurs varies
widely depending on the particle size and chemical properties of the
material deposited. Although radionuclides may be incorporated
subsequently into plants through absorption by the root system,
their concentration on the surfaces of vegetation will be the domi-
nant factor leading to a possible need for protective action.
[p. 5]
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GUIDELINES AND REPORTS
1139
ATMOSPHERE
FOOD CROPS
PASTURAGE
FEED CROPS
MEAT AND
MEAT PRODUCTS
ANIMALS
FRESH
FLUID MILK
AN
f
PROCESSED
MILK PRODUCTS
[p. 6]
SECTION III
PROTECTIVE ACTIONS AND THEIR APPLICATIONS
A protective action, within the scope of this report, is an action
or measure taken to avoid most of the exposure to radiation that
-------
1140 LEGAL COMPILATION—RADIATION
would occur from future ingestion of foods contaminated with
radioactive materials.
Since a protective action is taken to abate such an exposure risk
after the radioactive material has been released, in the develop-
ment of guidance for taking such action it is necessary to consider:
1. the possible risk to health associated with the projected dose to the popu-
lation from fission products.
2. the amount by which the projected doses can be reduced by taking certain
protective actions.
3. the total impact, including risks to health associated with these protec-
tive actions, and
4. the feasibility of taking the actions.
Protective actions are appropriate when the health benefit as-
sociated with the reduction in dose that can be achieved is con-
sidered sufficient to offset the undesirable factors associated with
the action.
The value of a protective action depends on how much the pro-
jected dose per individual can be reduced by the action and the
number of people affected. Protective actions will yield a greater
return in relation to their disadvantages if projected doses are
high rather than low. Since high levels of contamination probably
will be limited to small areas, protective actions are more likely to
be required in such areas rather than over large regions.
It is possible to estimate the projected dose that will result from
measured concentrations of radionuclides in the environment.
This estimate is usually related to a daily or total intake of radio-
active materials and can be based either on the assumption that
more materials will not be added to the food chain during the pe-
riod of concern, or that potential additions can be quantitatively
estimated. A quantitative estimate of the projected dose is neces-
sary for determining whether or not protective action should be
taken.
Impact of Protective Actions
A decision to implement a protective action involves a compari-
son of the risk due to radiation exposure with the undesirable
features of the contemplated action.
[p. 7]
The impact of the protective action will involve such factors as
the degree of departure from the usual practice, the length of time
over which the action is applied, the relative ease with which the
action can be executed, and possible health risks associated with
the action.
One of the well-established actions to reduce the intake of con-
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GUIDELINES AND EEPORTS 1141
taminants on foods is based on the fact that they are on the sur-
face of fresh fruits and vegetables. A large proportion of these
contaminants, including radioactive material, can be removed by
applying the usual practices of food preparation. The only de-
partures from these usual practices are that: (1) more attention
is given to insuring that the surfaces are washed, (2) the outer
leaves of leafy vegetables are removed, and (3) more than normal
preference is given to peeling.
The impact of these actions is small because they are already
accepted practice and no innovations are involved. If it were re-
quired that all fruits be peeled before eating, the impact would be
greater, and hence the risk would have had to be correspondingly
greater to warrant this degree of intervention in accustomed
activities.
Some actions, such as discarding a food item, involve a marked
departure from usual practice. They may, nevertheless, be of
low impact if limited to a small quantity of produce or to a small
area, or if applied infrequently and only for short periods.
The feasibility of executing a protective action depends on the
ease with which it can be applied by diversion of available re-
source factors such as the facilities, equipment, personnel, and
alternative supplies of animal feeds or agricultural produce needed
to implement the action. Diversion of a small fraction of readily
available resources is usually easy, but diversion of a large pro-
portion increases the impact and decreases the feasibility very
rapidly. There will be very few factors, possibly only one, that are
limiting in any complex of resources. These will not necessarily be
the same at each place or time the protective action may be needed.
Types of Protective Actions
The types of actions to which guidance in this report may be
related are:
1. Altering production, processing, or distribution practices affecting the
movement of radioactive contamination through the food chain and into the
human body. This action includes a storage of food and animal feed supplies
to allow for the radioactive decay of short-lived nuclides.
2. Diverting affected products to uses other than human consumption.
3. Condemning foods.
[p. 8]
Other possible types of action currently are judged to be less de-
sirable for reasons of effectiveness, safety, or practicality. The
use of additives in cattle rations, soil treatment, and the chemical
removal of radionuclides from milk are not included among the
types of actions listed.
-------
1142 LEGAL COMPILATION—RADIATION
Protective actions to reduce the intake of radioactive materials
by special alterations of the normal diet are accomplished best on
an individual basis under the supervision of medical authorities.
Application of Protective Actions
In providing guidance for protective actions applicable to radio-
active contamination of the environment, the Council is concerned
with a balance between the risk of radiation exposure and the im-
pact on public well-being associated with the alteration of the
normal production, processing, distribution, or use of food.
It is recommended that the term "Protective Action Guide"
(PAG) be used to indicate the projected dose at which the above
balance is judged to occur for the general types of protective ac-
tions considered in this section. Thus, the Protective Action Guide
serves as a basis for deciding when such protective actions are
indicated.
In the application of the Protective Action Guides the following
guidance is provided:
1. If the projected dose exceeds the PAG, protective action is indicated.
2. The amount of effort that properly may be given to protective action will
increase as the projected dose increases.
3. The objective of any action is to achieve a substantial reduction of dose
that would otherwise occur—not to limit it to some prespecified value.
4. Proposed protective actions must be weighed against their total impact.
Each situation should be evaluated individually. As the projected doses be-
come less, the value of protective actions becomes correspondingly less.
5. The Protective Action Guide is based on the assumption that the occur-
rence, in a particular area, of environmental contamination that would require
protective action is an unlikely event. Circumstances that involve either re-
petitive occurrence or in which there appears a substantial probability of
recurrence within a period of one or two years would require special considera-
tion. In such a case the total projected dose from the several events and the
total impact of the protective actions that might be taken to avoid the dose
from one or more of these events must be considered. In contemplating the
possibility of a future event it is necessary to consider not only the possible
magnitude but also the probability that the event will occur.
[p. 9]
6. Federal agencies should plan protective action programs designed to re-
duce the projected dose to individuals in the general public by modifying the
normal production, processing, distribution, or use of food products or animal
feeds. The need for implementing such plans should be determined on the
basis of the estimated projected dose and the appropriate PAG.
[p. 10]
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GUIDELINES AND REPORTS 1143
SECTION IV
GUIDANCE APPLICABLE TO IODINE-131
The Environmental Pathway
The physical and biochemical characteristics of iodine-131 make
it the radionuclide most likely to warrant rapid application of
protective actions. This is especially true if radioactive con-
tamination occurs before appreciable radioactive decay has taken
place.
The important pathway for iodine-131 from the source to the
body, and the one considered applicable to protective action cri-
teria, is through pasture to the cow, milk, and into the human body.
The shortest time-span from source to individual occurs when
fresh milk has not gone through processes of pasteurization and
distribution. Iodine-131 may appear in milk a few hours after
deposition on pasturage. From a single deposition it can reach a
maximum concentration in milk as early as two to four days after
deposition; it then decreases by half about every five days due to a
combination of radioactive decay and weathering losses from
grass.
Deposition of iodine-131 can vary greatly within a relatively
small geographical area. As a result, there can be large differ-
ences between the iodine-131 concentrations in milk produced on
farms only a few miles apart. Because of variations in deposition
and in animal feeding habits, and inadequate data for evaluating
the effects of these variations, it is not yet possible to predict re-
liably the maximum concentration of iodine-131 in milk from
deposition data.
Development of the Protective Action Guide Against Iodine-131
Factors affecting the relationships between exposures of hu-
mans to iodine-131 and subsequent biological effects have been dis-
cussed in FRC Reports No. 1 and No. 2, in a report * prepared for
[P. 11]
the FRC by the National Academy of Sciences Committees on the
Biological Effects of Atomic Radiation, and in the "Proceedings of
the Hanford Symposium on the Biology of Radioiodine."
According to these reports, the uptake of iodine-131 in the thy-
roids of children and adults is approximately the same. Thus a
given intake would result in a ten times larger dose to the thyroid
* Pathological Effects of Thyioid Irradiation—A report of a panel of experts from the Com-
mittees on the Biological Effects of Atomic Radiation; National Academy of Sciences; National
Research Council, published by the Federal Radiation Council, July 1962.
-------
1144 LEGAL COMPILATION—EADIATION
of a one year old child (thyroid weight 2 grams) than to an adult
(thyroid weight 20 grams). Children, one year of age are as-
sumed to be the critical segment of the population.
Young children treated with X-rays in the neck region for en-
larged thymus or for other benign head and neck conditions have
had a significantly higher incidence of tumors, including thyroid
carcinoma, than have children in control groups. Radiation doses
to the thyroid found to be associated with thyroid carcinoma under
these conditions range upward from about 150 rads. Experience
with exposure of the thyroid to large doses of radiation from
iodine-131 for therapeutic reasons is extensive but is almost en-
tirely confined to adults. The report of the panel of experts of the
NAS-NRC Committees states that, although therapeutic doses
from iodine-131 to the thyroid have been in the range of a few
thousand rads upward, iodine-131 has not been identified in a
causative way with the development of thyroid cancer in humans,
except in one doubtful case. X-ray doses to the thyroid appear to
be from 5 to 15 times as effective in producing biological changes
as iodine-131.
The initiation of protective action against contamination in the
environment resulting from a single event (i.e., an event isolated
in time from any other event that might affect the same area) in-
volves undesirable features that may be expected to vary in im-
portance from one circumstance to another. Of various actions
that might be effective in averting the major part of the projected
dose, two appear to provide the most acceptable combination of
maximum effectiveness and minimum undesirable consequences.
One of these is the diversion of contaminated milk to the produc-
tion of dairy products that may be stored conveniently until the
iodine-131 essentially has decayed, a matter of a few weeks. The
other is the substitution of stored feed for pasturage until most of
the iodine-131 has decayed. The choice may depend upon many
factors.
Considering existing information on the biological risks asso-
ciated with doses from iodine-131 and the kinds of protective ac-
tion available to avert the dose from iodine-131 that has been
deposited on pastures used by dairy cows, the Council has con-
cluded that such protective action as the diversion of milk or the
substitution of stored feed for pasturage to avert individual doses
less than 30 rads would not usually be justifiable under the con-
ditions considered most likely to occur. This dose is recommended
as the Protective Action Guide for iodine-131.
Generally it will not be practical to estimate individual doses.
In such cases decisions to take an action will be based on average
-------
GUIDELINES AND REPORTS 1145
values. As noted in FRC Report No. 1, paragraph 5.4, it is as-
sumed that the majority of the individuals do not vary from the
average by a factor greater than three. As an operational tech-
nique, it is considered that the PAG will not be exceeded if the
average projected doses to the thyroids of a suitable sample of the
population do not exceed 10 rads. A suitable sample is con-
sidered to consist of children of approximately one year of age
using milk from a reasonably homogeneous supply.
[p. 12]
The PAG is stated in terms of a projected dose; i.e., the dose
that might otherwise be received if the protective action were not
initiated. However, since the value of the contemplated action
and, consequently, the justification of the action, depends on the
dose averted, it is valid to use the projected dose as a basis for
implementation of a proposed protective action only if it is ex-
pected that most of the projected dose will be averted.
Because of the differences that may exist in various circum-
stances it is necessary to evaluate each situation individually. It is
not feasible to provide detailed criteria for taking into account dif-
ferences that may occur. In general, the PAG represents the
Council's judgment regarding the benefit-impact balance for the
two protective actions considered acceptable and for the conditions
considered most likely to occur. If -in a particular situation there
is available an effective action with low total impact, initiation of
such action at a projected dose lower than the PAG may be justi-
fiable. If only high impact protective action would be effective,
initiation of such action at a projected dose higher than the PAG
may be justifiable. For example, diversion of milk from fresh
milk channels to processed products may be less difficult in a lo-
cality where surplus production makes allocation between the two
uses a normal practice. The action would be more difficult and
expensive, and the total impact would be high if the milk had to be
transported large distances to a processing center, or if there were
adverse effects on the quality or quantity of milk available to the
consumer or adverse effects on the dietary habits of individuals in
the population.
In considering the net benefit of a protective action, assuming
the protective action is initiated at progressively lower values of
projected dose, as the projected dose becomes less, the net benefit
to public well-being from reduction of exposure becomes less.
Application of Protective Actions Against Iodine-131
The benefit of avoiding a potential dose from iodine-131 must
be evaluated against the feasibility and the disadvantages of any
-------
1146 LEGAL COMPILATION—RADIATION
protective action under consideration. A selected action must be
feasible for the particular situation. It must not be subject to
limitations such as lack of communications or transportation
which would nullify its effectiveness. If warranted under certain
unusual conditions, the application of protective actions in con-
secutive or concurrent operation may be considered. Local con-
ditions must also be considered. For example, the proportion of
fresh milk use to processed milk use in the area, or the seasonal
feeding pattern for cattle may affect the efficacy of a specific pro-
tective action.
Iodine-131 concentrations may vary widely within a given milk-
shed. Therefore concentrations at the point of milk production
must be known if efficient protective actions are to be taken. On
the other hand, concentrations at the point of consumption must
be known in order to evaluate the projected doses received by the
population group.
[P. 13]
Protetctive actions cannot attain maximum effectiveness with-
out adequate communications. Information regarding deposition
patterns and concentrations of radioiodine in milk must be ob-
tained promptly for those groups responsible for taking protective
action. The acceptance of and participation in protective actions
by milk producers, processors, distributors, and consumers must
be achieved. Such acceptance and participation will tend to avoid
unnecessary rejection of acceptable fresh milk supplies by the
public.
The specific protective actions considered in selecting the Pro-
tective Action Guide are:
1. The change of cattle from pasture to stored feed.
2. The substitution of unaffected fresh milk for affected fresh milk by alter-
ation of processing or distributing practices.
Preference for the second action may depend upon the practica-
bility of diverting the affected milk to the production of dairy
products which may be stored for several weeks before use. This
does not influence the effectiveness of the action in averting a dose
from iodine-131. In a sufficiently severe situation in which a more
desirable alternative did not exist, it might be appropriate to sub-
stitute unaffected milk for current use with no utilization of the
affected milk.
The projected future intake at any time after the maximum
concentration has been reached is approximately seven times the
estimated daily intake at that time, provided that additional iodine-
131 is not being deposited on the pasture. If the concentration of
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GUIDELINES AND REPORTS 1147
iodine-131 in milk has passed its maximum value and is decreasing
by half every five days, the relationship between the daily rate of
intake at any time and the total projected subsequent intake is in-
dicated in columns 1 and 2 of Table I.
Using the projected total intake, a projected dose for children
approximately one year of age may be calculated by assuming that
30 percent of the ingested iodine is retained in a 2 gram thyroid,
and by selecting an estimated value of 1 liter as the daily con-
sumption of milk. The relationship between the total intake of
iodine-131 and the projected dose is indicated in columns 2 and 3
of Table I.
A total intake of iodine-131 of 600 nanocuries would result in a
dose of about 10 rads to a 2 gram thyroid. In a single event, about
20 to 25 percent of the total intake may result from the use of that
portion of the milk produced before the maximum concentration
was reached. Under these conditions, and if no protective action
were taken, an estimated maximum concentration in milk of 60 to
70 nanocuries per liter would result in a total intake of about 600
nanocuries and a dose to the thyroid of 10 rads.
[p. 14]
TABLE 1.—INTAKE OF IODINE-131 FOR DIFFERENT RADIATION DOSES TO A 2-GRAM THYROID
FOLLOWING A SINGLE DEPOSITION OF IODINE-131 ON PASTURAGE'
Estimated intake
of iodine-131 in
one day at the
time of the max-
imum concentra-
tion or later
(nanocuries)
4.2
8.4
25
42
84
250
1250
2500
Projected intake
of iodine-131
(based on column 1)
(nanocuries)
29
58
175
290
580
1750
8750
17500
Projected
thyroid dose
(based on column 2)
(rads)
.5
1
3
5
10
30
150
300
1 This table is illustrative and does not indicate specific intake values at which protective actions
should be initiated or discontinued.
[p. 15]
The effectiveness of a protective action, if taken, will be highly
dependent upon the promptness with which it is initiated. If milk
from an unaffected area is to be substituted for the contaminated
milk, delay of initiation of the action by as much as 10 days after
the deposition occurs will reduce the total exposure that can be
avoided to substantially less than half of the total exposure that
-------
1148 LEGAL COMPILATION—RADIATION
would result if no action were taken. In the case of substitution
of stored feed for pasturage, the same delay would reduce even
further the benefit of the action because of the time required for
the iodine-131 in the cow and, consequently, the concentration in
the milk to decrease to negligible levels.
The exposure avoided will also depend upon the length of time
the protective action is maintained. In the case of substitution of
unaffected milk for contaminated milk, the reduction in the dose
that would result from subsequent intake would be about 90 per-
cent if the action were maintained for 15 to 20 days, and about 99
percent if maintained for 30 to 40 days. In the case of substitution
of stored feed for pasturage, reductions would be less.
Summary
Following release of fresh fission products iodine-131 is the
radionuclide considered most likely to reach concentrations in
foods which warrant protective action to reduce the projected
dose. The important mode of transmission to humans is through
the consumption of fresh fluid milk.
Iodine-131 can appear in milk within a few hours after its depo-
sition on pasture. The concentration in milk may reach a max-
imum in two to four days, after which the concentration
diminishes by half about every five days.
Removal of dairy cattle from contaminated pastures or the di-
version of contaminated milk to processed dairy products are rec-
ommended as protective actions to reduce human exposure from
iodine-131.
The Federal Radiation Council has developed the concept of the
Protective Action Guide. The PAG is defined as the projected ab-
sorbed dose to individuals in the general population which war-
rants protective action following a contaminating event.
A projected dose of 30 rads to the thyroid of individuals in the
general population has been recommended as the Protective Action
Guide for iodine-131. As an operational technique it is assumed
that this condition will be met effectively if the average pro-
jected dose to a suitable sample of the population does not exceed
10 rads.
[p. 16]
-------
GUIDELINES AND REPORTS 1149
4.1e(l) RADIATION PROTECTION GUIDANCE FOR
FEDERAL AGENCIES (MEMORANDUM TO THE
PRESIDENT), FEDERAL RADIATION COUNCIL
August 22,1964,29 Fed. Reg. 12056 (1964)
MEMORANDUM FOR THE PRESIDENT
JULY 16, 1964.
Pursuant to Executive Order 10331 and Public Law 86-373, the
Federal Radiation Council is transmitting recommendations for
the approval of the President for guidance of Federal agencies in
their radiation protection activities. The present recommenda-
tions are directed to guidance for protective actions affecting the
normal production, processing, distribution, and use of food prod-
ucts for human consumption. Specific guidance is provided for
iodine-131. It is the intention of the Council to release the back-
ground material leading to these recommendations as Staff Report
No. 5 when the recommendations herein are approved.
Background. The first two memorandums which provided
guidance for Federal agencies in the conduct of their radiation
protection activities were approved by the President on May 13,
1960, and September 20, 1961. These provided a general philoso-
phy of radiation protection and general principles of control based
on the annual intake of radionuclides. The recommendations
contained therein provided the basis for the control and regulation
of normal peacetime operations in which exposure to radiation is
a factor. Numerical values were provided for the Radiation Pro-
tection Guides designed to limit the exposures of the whole body
and of certain organs resulting from normal peacetime operations.
During the period of atmospheric testing of nuclear weapons in
1961 and 1962 the question arose as to the use of these Radiation
Protection Guides for determining the conditions under which the
production, processing, distribution, and use of food, particularly
fresh fluid milk, should be altered to reduce human intake of
radionuclides from fallout.
In September 1962 the Federal Radiation Council stated its po-
sition on this subject, and in 1963 the Council reiterated that exist-
ing guides were not applicable to a determination of a need for
protective actions and noted that it would recommend guidance on
the subject to the President.
Concept of Protective Action Guide. In previous reports the
Federal Radiation Council has recommended a philosophy of radi-
ation protection and discussed alternative approaches to the deri-
vation of basic guidance for radiation protection. It has pointed out
-------
1150 LEGAL COMPILATION—RADIATION
that decisions concerned with radiation protection involve a balance
between the possible health risks associated with radiation expo-
sure and the reasons for accepting the exposure. The Council
accepted the term "Radiation Protection Code" to express the bal-
ance between the benefits from normal peacetime operations and
the health risks associated with those exposures. The radionuclide
releases causing these exposures are generally controlled at the
source.
Radiation protection guidance for protective actions applicable
to ingestion of food contaminated with radioactive material re-
quires a different balance. Here, the Council is concerned with a
balance between the risk of radiation exposure and the impact on
public well-being associated with alterations of the normal produc-
tion, processing, distribution, and use of food.
For this purpose, the Council has adopted the term "Protective
Action Guide" (PAG), defined as the projected absorbed dose to
individuals in the general population which warrants protective
action following a contaminating event. The projected dose is the
dose that would be received in the future by individuals in the pop-
ulation group from the contaminating event if no protective action
were taken. If the projected dose exceeds the PAG, protective ac-
tion is indicated. According to the operational technique adopted
in the Memorandum for the President, May 1960, the correspond-
ing average projected dose to a suitable sample of the exposed
population would be one-third of the PAG.
A protective action is an action or measure taken to avoid most
of the exposure to radiation that would occur from future inges-
tion of foods contaminated with radioactive materials. Such ac-
tions are appropriate when the health benefits associated with the
reduction in exposure to be achieved are sufficient to offset the un-
desirable features of the protective actions. The PAG represents
the Council's judgment as to where this balance should be for the
conditions considered most likely to occur. If, in a particular
situation, there is available an effective action with low total im-
pact, initiation of such action at a protected dose lower than the
PAG may be justifiable. If only very high impact action would be
effective, initiation of such action at a projected dose higher than
the PAG may be justifiable.
A basic assumption in the development of the guidance in this
memorandum is that a condition requiring protective action is un-
usual and should not be expected to occur frequently. In any
event, the numerical values selected for the Protective Action
Guides are not intended to authorize deliberate releases expected
to result in absorbed doses of these magnitudes.
-------
GUIDELINES AND EEPORTS 1151
The types of actions to which application of the Protective Ac-
tion Guides may be related are:
1. Altering production, processing, or distribution practices affecting the
movement of radioactive contamination through the food chain and into the
human body. This action includes storage of food supplies and animal feeds
to allow for radioactive decay.
2. Diverting affected products to uses other than human consumption.
3. Condemning affected foods.
Measures that require an alteration of the normal diet are generally less
desirable than those listed and should not be undertaken except on the advice
of competent medical authorities.
Radionuclides considered. Four radionuclides are of particular
importance in considering radioactive contamination of food.
These are iodine-131, strontium-89, strontium-90, and cesium-137.
This memorandum will deal only with iodine-131.
In contrast to the other fission nuclides, the relatively high yield
of iodine-131 and the short radioactive half-life (8 days) of iodine-
131 make it the radionuclide most likely to reach concentration
justifying protective actions. This is especially true if the depo-
sition occurs within a few days after the fission event. Protective
action against iodine-131 must be taken promptly in order to be
effective.
Physicial and biological factors related to iodine-131 have been
considered in FRC Reports No. 1 and No. 2. As in FRC Report
No. 2, it is assured that children one year of age, with a thyroid
weight of 2 grains and 30 percent uptake of iodine-131, are the
critical segment of the population.
Protective actions against iodine-131. The Council has evaluated
the kinds of protective actions available for use against iodine-131,
the health benefit that may result by averting a radiation dose
larger than the Protective Action Guide, and the probable impact
of taking the actions. Of various actions that might be effective in
averting the major part of the potential exposure, two appear to
provide the most acceptable combinations of maximum effectiveness
and minimum undesirable consequences. One of these is the di-
version of fresh milk to provide unaffected milk in the contam-
inated area and to use the affected milk in the production of dairy
products that may be conveniently stored until the iodine-131 has
effectively decayed, a matter of a few weeks. The other is the
substitution of stored feed for pasturage, until most of the iodine-
131 has decayed.
Recommendations. In view of the considerations summarized,
the following recommendations are made.
It is recommended that:
-------
1152 LEGAL COMPILATION—RADIATION
1, The term "Protective Action Guide" (PAG) be adopted for
Federal use.
The Protective Action Guide is defined as the projected ab-
sorbed dose to individuals in the general population which war-
rants protective action following a contaminating event. The pro-
jected dose is the dose that would be received in the future by indi-
viduals in the population group from the contaminating event if
no protective action is taken.
It is recommended that:
2. The Protective Action Guide for iodine-131 be 30 rads to the thyroid.
If the projected dose exceeds the Protective Action Guide, protective action is
indicated.
According to the operational technique adopted in the Memorandum for the
President, May 1960, the corresponding average projected dose to the thyroids
of a suitable sample of the exposed population group would be 10 rads.
3. The guidance contained herein be approved for the use of Federal agencies
in the conduct of those radiation protection activities affecting the normal pro-
duction, processing, distribution, and use of food and agricultural products.
ANTHONY J. CELEBREZZE,
Chairman.
The recommendations numbered "1" through '3" contained in
the above memorandum are approved for the guidance of Fed-
eral agencies, and the memorandum shall be published in the
FEDERAL REGISTER.
LYNDON B. JOHNSON.
4.1f REVISED FALLOUT ESTIMATES FOR 1964-65 AND
VERIFICATION OF THE 1963 PREDICTIONS, REPORT NO. 6,
STAFF REPORT OF THE FEDERAL RADIATION COUNCIL,
MAY 1965.
CONTENTS
Page
List of Tables and Figures 1
Summary 2
Section:
I.—Introduction 4
II.—The Inventory of Long-lived Radionuclides 5
III.—Radionuclides in the Diet and in People 13
[p. iii]
-------
GUIDELINES AND REPORTS 1153
LIST OF TABLES AND FIGURES
Table
1 Expected Annual Deposition of Strontium-90 in the United States.
2 Global Strontium-90 in the Atmosphere Month of January.
3 Comparison of Predicted and Observed Levels of Radionuclides Deposited
and in the U.S. Diet in 1963.
4 Average Strontium-90 Content of Milk in the U.S.
5 Strontium-90 Content of Wheat and Flour in the U.S.
6 Average Strontium-90 Content of U.S. Total Diet.
7 Average Strontium-90 Content of Ehiman Bone in the U.S.
Figure
1 Strontium-90 Deposition over the United States during 1963.
2 Time History of Strontium-90 Surface Deposition.
3 Mean Distribution of Strontium-90 in the Atmosphere.
4 Average Concentration of Radionuclides in Milk Samples from Public
Health Service Pasteurized Milk Network.
5 Strontium-90 Concentrations in Pasteurized Milk.
[p.l]
SUMMARY
On the basis of information available in June 1964, new esti-
mates of the levels of fallout expected in 1964 and 1965 from the
atmospheric testing of nuclear weapons conducted through 1962
have been made by the Federal Radiation Council.
Based on the stratospheric inventory of strontium-90 in January
1964, the predicted annual depositions in 1964 and 1965 have been
increased by 50 percent over those presented in FRC Report No. 4.
This adjustment is well within the expected uncertainty of the
original estimate and does not change the 30-year and 70-year dose
estimates made on the basis of the original predictions.
The inventory of long-lived fission products such as strontium-90
and cesium-137 in the atmosphere by mid 1964 was reduced to one-
half that in January 1963.
The deposition of fallout in the United States in 1963 was very
close to the predicted values. The average deposition in the "wet"
areas was a little less than predicted and that in the "dry" areas a
little more. The time of maximum deposition occurred about a
month later than it has in previous years.
Iodine-131 from the atmospheric testing of nuclear weapons had
disappeared by May 1963 and strontium-89 by June 1964.
The observed levels in 1963 for strontium-89, strontium-90, and
-------
1154 LEGAL COMPILATION—RADIATION
cesium-137 in milk and dairy products, short-lived nuclides leading
to external exposure, and carbon-14 in the atmosphere at ground
level were all very close to the values predicted in FRC Report No.
4. The observed values of strontium-90 in the total diet and in
new bone were less than predicted for 1963. This discrepancy is
[P. 2]
considered to result from the fact that some non-dairy products,
particularly cereal grains, do not enter the diet in significant
quantities in the same year in which they are grown.
New predictions for the strontium-90 and cesium-137 levels in
milk, and strontium-90 in cereal grains and the total diet expected
in 1964 and 1965 have been made to reflect the adjusted annual fall-
out level and the lag time for cereal grain products to enter the
diet. These predictions are that the levels of long-lived radio-
nuclides in milk in 1964 will be about the same as they were in
1963. The strontium-90 concentrations in the total diet in 1964
are expected to be higher than they were in 1963 and to drop to
1963 levels in 1965.
Based on the predictions of dietary contamination levels antic-
ipated in 1963 and subsequent years, the Council concluded in FRC
Report No. 4 that the health risks from radioactivity in food over
the next several years are too small to justify protective actions to
limit the intake of radionuclides by diet modifications or altering
the normal distribution and use of food, particularly milk and
dairy products. The present study has shown that the predictions
in FRC Report No. 4 were substantially correct, and the con-
clusions in that report still apply.
[P. 3]
SECTION I
INTRODUCTION
1.1 In FRC Report No. 4, issued May 1963, the Federal Radia-
tion Council evaluated the levels of fallout that might be antic-
ipated in the United States in 1963 and subsequent years following
the programs of atmospheric nuclear weapons testing conducted
through 1962. The report forecast a substantial increase in the
probable levels of radionuclides from fallout during 1963 with
decreasing quantities in subsequent years.
1.2 On the basis of the radiation doses associated with these
levels, it was concluded that the health risk from radioactivity in
foods anticipated over the next several years would be too small to
justify protective actions to limit the intake of these radionuclides
by altering the normal production, processing, and distribution of
food, particularly milk and dairy products.
-------
GUIDELINES AND REPORTS 1155
1.3 The purposes of the present report are to: (1) compare
the predictions made as to the levels of fallout anticipated in 1963
with the experience based on surveillance measurements, (2) make
more precise estimates of the levels anticipated in 1964 and 1965,
and (3) evaluate the validity of the prediction procedures when
they are applied to a changing fallout situation such as now exists.
The study is based on information available through June 1964.
Although the probable average levels for 1964 can be projected di-
rectly from currently available surveillance information, new esti-
mates of the anticipated average levels of radionuclides in food in
1964 and 1965 utilize the stratospheric inventory data and the
cumulative levels in soil as of January 1964.
[p. 4]
SECTION II
THE INVENTORY OF LONG-LIVED RADIONUCLIDES
Verification of Predicted 1963 Fallout
2.1 As an aid in presenting the predictions contained in FRC
Report No. 4, the regions in the United States were divided into
"wet" and "dry" areas depending on average annual rainfall
(roughly separated by the 20" rainfall isoline). The deposition of
strontium-90 in 1963 was expected to average 50 me/mi2 (milli-
curies per square mile) in the wetter regions and 20 me/mi2 in the
drier regions. A considerable range of variability within each
climatic area was expected due to rainfall and other differences
(depositions in the "wet" areas were expected in the range of
30-60 me/mi2 and those in the "dry" areas, 10-30 me/mi2).
2.2 The verification of the 1963 strontium-90 fallout over the
United States appears on the large map shown in Figure 1. The
shading in Figure 1, taken from FRC Report No. 4, separates the
"wet" (heavy shading) from the "dry" (unshaded) areas. The
light shading in the midwestern United States denotes areas with
slightly less than 20 inches of annual precipitation while the lighter
shading over the state of Florida indicates an expected lesser fall-
out compared with the "wet" eastern United States because of its
sub-tropical location.
2.3 The fallout in "wet" areas generally lies in the 30-60 me/
mi2 range. No station reported a value in excess of 60 me/mi2.
The average derived from the isolines in the "wet" areas is about
45 me/mi2 or within about 10 percent of the predicted average.
Fallout in the drier regions of the United States was expected to
be about four-tenths as large as that in the "wet" regions. Except
for a few areas, deposition values were below the predicted upper
-------
1156 LEGAL COMPILATION—RADIATION
value of 30 me/mi2. The observed mean value derived from the
isolines is about 25 me/mi2, which is about 25 percent greater than
the prediction of fallout in the "dry" area.
[P. 5]
2.4 It should be noted that the prediction of fallout for the year
1963 contained the possibility that it might be in error by a factor
of two. Thus, the 10 and 25 percent discrepancies fall well within
the uncertainty in the prediction. The north central United States
appears to have received higher fallout and the south central and
southwestern United States lower fallout than expected.
2.5 The 1963 fallout data and a reexamination of the results
from earlier years suggest that the designation of the "wet" and
"dry" areas be modified to conform with observed fallout data.
The redefined areas are shown in the inset in Figure 1.
2.6 It should also be noted that the seasonal variation in the
deposition of strontium-90 during 1963 differed from that in pre-
vious years. Figure 2 presents the time history of fallout in each
hemisphere. Fallout in the United States closely follows that of
the northern hemisphere. From 1958 through 1962 the peak
northern hemisphere fallout occurred in March, April, or May.
On the average, about 70 percent of the annual fallout is deposited
in the first six months of each calendar year. However, in 1963
the peak concentration extended into July and it took seven, rather
than six, months for 70 percent of the annual fallout to be
deposited.
Predictions of Future Fallout
2.7 The procedures used to predict the fallout anticipated in the
future are the same as those described in FRC Report No. 4, and
are based on measurements of the stratospheric inventory of stron-
tium-90 as it existed in January 1964.
2.8 To reflect the stratospheric inventory as of January 1964,
the predictions of the fallout expected in 1964 appearing in Table
1 have been increased by 50 percent over the prediction made for
the same year in FRC Report No. 4 (1963). This increase lies
well within the expected uncertainty of a factor of two or more
attributed to the forecast for 1964 made in that report. The fore-
cast for 1964 given in the present report is expected to be verified
well within a factor of two.
[p. 6]
2.9 Table 1 also contains a prediction of 1965 fallout. This fore-
cast has also been increased by 50 percent over that previously re-
ported. The uncertainty in the present 1965 prediction is greater
-------
GUIDELINES AND REPORTS 1157
than a factor of two. If the predictions are in error, there is
more likely to be an overestimation of the 1965 fallout than an
underestimation.
2.10 Table 2 lists the partition of strontium-90 in various parts
of the atmosphere (to 100,000 feet) from 1963 to 1965. Figure 3
and Table 2 emphasize the presence of greatest concentrations in
the northern hemisphere. It is likely that in a few years there
will be a tendency for equality between hemispheres as suggested
in Table 2. Thus, after the 1964 and 1965 fallout has been de-
posited, roughly one-half of the remaining stratospheric inventory,
about one megacurie, should be in the stratosphere of the northern
hemisphere. It may therefore be anticipated that in the years
following 1965 the total additional strontium-90 deposition will be
about 10 and 25 me/mi2 in the "dry" and "wet" United States
respectively.
2.11 The total inventory of strontium-90 on the ground will in-
crease until the fraction lost each year by radioactive decay equals
the annual deposit. On the basis of present information it is an-
ticipated that this condition will have been reached by 1967. The
total inventory of strontium-90 on the earth's surface will then
continue to decrease in subsequent years.
2.12 The increase in carbon-14 in the atmosphere at ground
level predicted in FRC Report No. 4 has been verified by observa-
tions made in 1963, and original predictions in that report are
considered to be substantially correct.
[p. V]
-------
1158
LEGAL COMPILATION—RADIATION
=1 =5
a) 3
[p. 8]
-------
GUIDELINES AND REPORTS
1159
a,
•8
s-
•*o
w
04
a
s
[p. 9]
Sr-90 Megacuries/Month
-------
1160 LEGAL COMPILATION—RADIATION
TABLE 1.—EXPECTED ANNUAL DEPOSITION OF STRONTIUM-90 IN THE UNITED STATES.
[millicunes per square mile]
Variability
Most probable value within area
Accumulated deposition to January 1, 1964:
"Wet" area 150 120-190
"Dry" area 65 40-85
Expected deposition during 1964:
"Wet" area 30 15-60
"Dry" area 12 5-20
Expected Deposition during 1965:
"Wet" area 15 5-25
"Dry" area 6 2-10
Expected Total Deposition after January 1, 1966:
"Wet" area 25 10-50
"Dry" area 10 5-20
Note: Designation of "wet" and "dry" areas have been modified slightly since FRC Report No. 4 (see
fig. 1).
In each year, it is expected that about 70 per cent of the annual fallout will occur in the first 6 months
of the year.
[p.10]
TABLE 2.—GLOBAL STRONTIUM-90 IN THE ATMOSPHERE MONTH OF JANUARY (MEGACURIES)
Northern hemisphere:
Stratosphere
Southern hemisphere:
Stratosphere
Total observed
Total observed:
(Both hemispheres)
1963
5.7
0.3
6.0
0.5
0.1
0.6
6.6
1964
3.4
0.2
3.6
0.6
0.1
0.7
4.3
Predicted
2.1
0.1
2.2
0.6
0.1
0.7
2.9
[P.
1965
11]
-------
GUIDELINES AND REPORTS
1161
5100
90*N 60°N
60°S 90°S
[p. 12]
FIGURE 3.—Mean distribution of strontium-90 in the atmosphere. Observed
by Project Star Dust, the Department of Defense's stratospheric surveillance
project, January 1964. (Disintegration per minute per 1,000 standard cubic
feet).
SECTION III
RADIONUCLIDES IN THE DIET AND IN PEOPLE
General Considerations
3.1 This section is concerned with that part of the fallout which
enters the food chain of man. Inhalation of radioactive materials
and external sources from fallout are not discussed in this report.
Both strontium-90 and cesium-137 have been measured in the total
diet and various diet components. Quantitative relationships at-
tempting to relate the radionuclide levels in the total diet and diet
components to the quantity of fallout deposited, however, have
been studied much more extensively in regard to strontium-90.
3.2 The predictions have been made by a special ad hoc group
of technical representatives of all interested agencies in the Fed-
eral Government. The detailed methodology has been reported
in the hearings of the Joint Committee on Atomic Energy, "Fall-
out, Radiation Standards, and Countermeasures," June 3, 4, and
-------
1162 LEGAL COMPILATION—RADIATION
6, 1963, and in technical reports of the Health and Safety Lab-
oratory, U.S. Atomic Energy Commission.
3.3 These prediction procedures have been developed to describe
the general situations as found in the conterminous United States.
Special situations, such as the lichen-caribou-man food chain in
Alaska require different procedures to adequately describe them.
The factors concerned in this food chain are the subject of studies
being conducted by the Atomic Energy Commission and the Public
Health Service.
3.4 The general considerations related to estimates of the stron-
tium-90 content of the total diet and diet components were out-
lined in FRC Report No. 4. Milk, fresh fruits, and fresh
vegetables are distributed regionally or locally. Therefore, these
[p. 13]
items in the diet tend to reflect the local levels of fallout. Differ-
ences in the strontium-90 to calcium ratio of the total diet in dif-
ferent localities should be related primarily to the strontium-90 in
these dietary items. Nationally distributed processed foods tend
to lead to a contribution of strontium-90 that is about the same in
all parts of the country. The delayed marketing and consumption
of such nationally distributed foods introduces a lag between the
time of fallout deposition and the appearance of strontium-90 in
the total diet.
3.5 Predictions of the anticipated levels of strontium-90 in the
diet and diet components may be made by one or both of two gen-
eral procedures: (1) Prediction of the contamination levels ex-
pected in different dietary components as a function of the fallout
rate and cumulative levels of strontium-90 in the soil, and the cal-
culation of total diet levels on the basis of the contribution each
component makes to the total diet; or (2) multiplying the stron-
tium-90 value for milk by an empirically developed factor related to
the fractional contribution of milk to the strontium-90 and calcium
intake in the total diet. This factor changes when the rate of
fallout deposition changes.
3.6 The predictions for strontium-90 in the total diet and milk
as presented in both FRC Report No. 4 and the present report are
based on estimates made for New York City as representative of
the "wet" areas and for San Francisco as representative of the
"dry" areas. This practice has been adopted because the numer-
ical constants relating the fallout rate and the cumulative levels of
strontium-90 in soil to the respective dietary contamination levels
in these cities are the best estimates available for these factors and
also because bone sampling in these areas is correlated with the
diet sampling. Strontium-90 and cesium-137 levels in milk and
-------
GUIDELINES AND REPORTS 1163
the total diet have been measured in many localities throughout
the country under programs sponsored by the Food and Drug Ad-
ministration, the U.S. Public Health Service, and the Atomic En-
ergy Commission. Averages computed from these data for the
"wet" and "dry" areas, as described in Figure 1, indicate that the
averages for "wet" and "dry" regions as a whole will usually be
comparable to the values predicted for New York and San Fran-
cisco respectively.
[p. 14]
Verification of 1963 Estimates
3.7 Based on the information available in early 1963, estimates
of the anticipated levels of strontium-90, strontium-89, cesium-137,
and iodine-131 in the diet and some diet components were made in
FRC Report No. 4. The evaluation of iodine-131 data observed in
1963 was incorporated in FRC Report No. 4. It was also estimated
that the annual average strontium-89 concentration in milk would
be about the same in 1963 as it had been in 1962, and that this nu-
clide would be reduced to negligible levels in 1964. The observed
average concentrations of iodine-131, strontium-89, strontium-90,
and cesium-137 in milk from the middle of 1961 through June 1964
are shown in Figure 4. This figure illustrates the general trends.
The network average is plotted instead of the separate values for
the "wet" and "dry" areas. It can be seen that iodine-131 was
essentially gone by May 1963 and strontium-89 by June 1964.
3.8 The estimates for the longer-lived nuclides in the diet and
in people were presented in the form of the expected annual av-
erage for the "wet" and "dry" areas as described in Figure 1.
These estimates were based on the most probable value of the an-
nual fallout deposit, the expected distribution of this annual in-
crement by month, and the cumulative deposit on the ground at the
beginning of 1963.
3.9 Table 3 compares the observed levels of strontium-89, stron-
tium-90, and cesium-137 in the 1963 diet and strontium-90 in the
bone with the anticipated annual averages for the "wet" and "dry"
areas. The observed values reported are based on all surveillance
data available. Figure 5 shows isolines of the annual average con-
centrations of strontium-90 in milk based on the Pasteurized Milk
Network of the U.S. Public Health Service. The computed av-
erages are 27 and 16 picocuries strontium-90 per liter for the "wet"
and "dry" areas respectively. The agreement between the pre-
dicted and observed values is quite good in all categories except
for the strontium-90 to calcium ratio in the total diet and new
bone. The diet values, which represent the predictions for the final
-------
1164 LEGAL COMPILATION—RADIATION
step in the chain of this radionuclide transmitted through the en-
[p. 15]
vironment to man, were overestimated by a factor of 1.7 for the
"wet" areas and 3.5 for the "dry" areas.
3.10 The predictions in FRC Report No. 4 for strontium-90 in
the diet were made before most of the 1963 fallout occurred and
before some crops were grown. The predictions were not expected
to differ from the observed values by more than a factor or two.
The discrepancy between the predicted and observed value for
the total diet is larger than expected. It is now apparent from
detailed studies that non-milk products contributed less to stron-
tium-90 content of the total diet in 1963 than would be calculated
by the past prediction procedures used in relating fallout rate to
the strontium-90 content of the total diet. Adjustments in the pre-
diction procedures will be discussed in connection with the new
estimates. (Par. 3.23)
3.11 Table 3 shows two values for the strontium-90 to calcium
ratio in bone. The ratio in new bone being formed is one-fourth
that in the average diet because the body selectively discriminates
against strontium. The observed value for new bone is based on
a few measurements on infants less than 1 year old. The observed
value for the average of the 0-4 year age group is less because, in
the older children, the concentration of strontium-90 is diluted
more by the calcium already present.
3.12 The 1963 predictions of 50 and 35 picocuries strontium-90
per gram calcium as the expected values for the total diet in the
"wet" and "dry" areas respectively led to predicted concentrations
of 12 and 9 picocuries strontium-90 per gram calcium in new bone
formed in 1963. The observed values of 7 and 2 picocuries stron-
tium-90 per gram calcium for new bone and 5 and 3 picocuries
strontium-90 per gram calcium in the 0-4 age group are in good
agreement with the observed ratios in the total diets in 1963.
However, they are lower than the values of 12 and 9 picocuries
strontium-90 per gram calcium reported in FRC Report No. 4 as
the values expected to result from fallout anticipated in 1963.
[p. 16]
Predictions of Future Levels
3.13 After the termination of atmospheric testing, iodine-131
essentially disappeared from the environment by May 1963 and
strontium-89 by June 1964. New predictions will be made for only
the long-lived nuclides strontium-90 and cesium-137.
-------
GUIDELINES AND REPORTS 1165
Milk
3.14 The raiodnuclide concentrations in fresh milk follow closely
the radionuclide content of the cow's fodder. In many parts of the
country, the dairy cows are put on pasture in the spring, and dur-
ing the months while the cows are on pasture the radionuclide con-
centration in milk varies with the fallout rate. As indicated in
Section II, a maximum in the fallout rate is usually reached in
April, May, or June. Strontium-90 and cesium-137 concentrations
in milk usually increase to a maximum in these months, followed
by steadily diminishing concentrations during the summer and
early fall. This decrease reflects the lower fallout rate during
these seasons plus the loss of surface deposits through weathering,
new growth replacing the contaminated grass, and normal changes
of feeding practices during the season. When the cows are shifted
to stored fodder the radionuclide concentration in milk then re-
flects the content of the fodder. The slight perturbation in the
pattern of fallout deposited by month in 1963 as compared to
previous years .did not have much effect on the annual average
concentrations in milk possibly because dairy cattle were on pas-
ture in many parts of the country during the whole period of
interest.
3.15 Table 4 summarizes the data on the average strontium-90
content of milk from 1959 through 1963 and presents new pre-
dictions for 1964 and 1965. These predictions reflect the new
values for the annual increment of fallout in 1964 and 1965, as
shown in Table 1, and the cumulative level of strontium-90 in the
soil at the beginning of 1964. Figure 4 shows the trends in av-
erage concentrations of strontium-90 and cesium-137 in milk
through June 1964. A breakdown of the data into separate esti-
mates for the "wet" and "dry" areas suggests that the prediction
for the average concentration of strontium-90 in milk of the "wet"
[p. 17]
areas in 1964 will probably be very close to the observed value and
that the prediction for the "dry" areas may be less than the ob-
served value. This possible discrepancy is not expected to exceed
a factor of two.
3.16 The formulas used to relate cesium-137 concentrations in
milk to the fallout rate and the cumulative deposit of cesium-137
on the ground are more uncertain than those for strontium-90. On
the basis of present information it is expected that the average
concentration of cesium-137 in milk in 1964 will be about the same
as it was in 1963 and will decrease in 1965. The ratio of cesium-
137 to strontium-90 is not expected to remain constant with time
-------
1166 LEGAL COMPILATION—RADIATION
because of the different mechanisms involved in the movement of
these nuclides through the food chain to milk. In general, the
cesium-137 concentrations are expected to decrease faster than the
strontium-90 concentrations.
Wheat and Flour
3.17 The strontium-90 content of wheat and flour in the United
States from 1959 through 1961 was shown in Table 8 of FRC Re-
port No. 4. The analyses of the 1962 crop were not available at
the time that report was written, so the expected value in 1962
was estimated on the basis of what was known about the fallout
rate in 1962. The expected values of strontium-90 per kilogram
of wheat were given as 130 picocuries in 1962, 250 picocuries in
1963, and 100 picocuries in 1964.
3.18 Table 5 summarizes the average concentrations of stron-
tium-90 observed in wheat and flour from 1959 through 1963 and
makes new predictions for 1964 and 1965. The observed value of
strontium-90 in 1962 wheat was 40 per cent less than the esti-
mated value used in preparing the estimates of FRC Report No. 4.
There is good agreement between the predicted and observed
values for the 1963 crop.
3.19 The contamination of cereal grains by fallout appears to
be far more sensitive to the fallout rate between the time the grain
has headed out and harvest than to either the cumulative total in
the soil or to the total annual increment of fallout. This time-span
[p. 18]
is about 6 to 8 weeks for the most important crops, and makes the
relative levels of contamination from year to year very sensitive
to perturbations in the fallout rate by month. Under these condi-
tions it is not surprising to find large variations in the same crops
grown in different areas, or different crops grown in the same
areas. The difference between the predicted and observed values
for 1962 may be attributable at least in part to this cause.
3.20 The new estimates for 1964 and 1965 are based on the ad-
justed figures for the annual increment of fallout for those years
as shown in Table 1 and the cumulative level of strontium-90 in the
soil at the beginning of 1964. The formula used in making the
present predictions assumes that the level of contamination in
wheat is primarily determined by the fallout rate in the month of
June of each year.
Total Diet
3.21 The levels of cesium-137 in the total diet in 1964 are ex-
pected to differ from those observed in 1963 by about the same per-
-------
GUIDELINES AND REPORTS 1167
centage as strontium-90 in the total diets for the same years. The
factors entering the prediction of the strontium-90 content of the
total diet have been discussed in paragraphs 3.1-3.6. Tabulated
predictions have been given for the strontium-90 levels in milk and
wheat. Wheat may be considered representative of the cereal
grains. In the past, these two components have accounted for 60
to 70 percent of the total strontium-90 intake and about 75 percent
of the total calcium intake in the United States diet. The ratio of
strontium-90 to calcium in the total diet should be close to the ratio
estimated from these two components. The strontium-90 intake
through fruits and vegetables is subject to a considerable regional
variation. This source accounts for most of the remaining 30 per-
cent of strontium-90 and an additional 13 percent of calcium.
3.22 Observations of the strontium-99 to calcium ratio in the
total diet compared to that in milk have generally fluctuated be-
tween 1 and 2 for the past several years. The most logical ex-
planation for this variability appears to be that the lower values
[p. 19]
of the total diet to milk ratio occur during the periods of increased
fallout deposition when the strontium-90 in milk, fresh fruits, and
fresh vegetables is increasing; other non-milk components reflect
the strontium-90 to calcium ratio of products grown before the
fallout deposition started increasing. Following a period of rel-
atively high fallout desposition and when the deposition rate is
decreasing, the strontium-90 to calcium ratio in milk decreases.
However, relatively high ratios of strontium-90 to calcium may be
found in the total diet because the non-milk components will reflect
the strontium-90 to calcium ratio of products grown during the
time of the higher fallout deposition rate. It has been assumed
that the strontium-90 to calcium ratio of the total diet will be 1.5
times the predicted value for milk for purposes of long-term pre-
diction. However, this ratio (1.5) cannot be considered reliable
for developing short-term predictions especially when the annual
rate of fallout deposition changes such as it has done since 1962.
3.23 The predictions in FRC Report No. 4 utilized both the diet
to milk ratio method and the procedure of directly predicting the
anticipated strontium-90 levels in different dietary components.
For the direct estimates it was assumed that the time lag between
the production of all dietary components and the entry of the pro-
duce into the market is less than one year. In the present report,
it is assumed that milk products and fruits and vegetables are
consumed in the same year in which the products are produced.
However, for the cereal grains it is assumed that 25 percent comes
from the crop grown during the year of interest while 75 percent
-------
1168 LEGAL COMPILATION—RADIATION
comes from the crop grown during the previous year. New pre-
dictions for the strontium-90 to calcium ratio of the total diet are
shown in Table 6. These predictions reflect the adjusted esti-
mates of the fallout deposition rates for 1964 and 1965 as shown
in Table 1.
3.24 When the adjusted assumptions are applied to the 1963 fig-
ures, the "predicted" values would be 40 and 20 picocuries stron-
tium-90 per gram calcium for the total diets of the "wet" and "dry"
areas respectively. Although these values are closer to the ob-
served values of 30 and 10 picocuries strontium-90 per gram
[P. 20]
calcium than the original predictions of 50 and 35 picocuries
strontium-90 per gram calcium, the adjusted assumptions would
still overestimate the strontium-90 contamination of the total diet
as it existed in 1963. However, the new predictions of 40 and 20
picocuries strontium-90 per gram calcium for the total diet in the
"wet" and "dry" areas respectively in 1964 may be closer to the
observed annual averages since 1964 is the second successive year
of relatively high fallout deposition.
Bone
3.25 The ratios of strontium-90 per gram calcium in bone ob-
served in the past and predicted for the future are shown in Table
7. The numerical values for 1964 and 1965 are one-fourth the
predicted ratio of strontium-90 to calcium in the total diet shown
in Table 6. The difference between the strontium-90 concentra-
tions in new bone being formed and the average level in the 0-4
year age group (illustrated in Table 3) is expected to decrease
with time.
Dose Estimates
3.26 The estimates made in FRC Report No. 4 for the expected
30-year and 70-year doses are not altered by the revised estimates
of radioactive nuclides in the diet. The doses estimated for ex-
ternal exposure from short-lived nuclides and for strontium-89
correspond to the observed values for these nuclides in 1963. The
shift of one year in the time of the maximum value of strontium-90
expected in the diet has very little effect on the estimated 70-year
dose from strontium-90.
3.27 During the past three years a whole body counter has been
used to measure the cesium-137 body burdens of the inhabitants of
several villages in artic Alaska chosen to evaluate environmental
factors and dietary patterns unique to that region. Estimates of
doses to individuals in 1964 based on these measurements range up
to about 400 millirems. Depending upon the further fallout ex-
-------
GUIDELINES AND REPORTS
1169
pected and the long-term retention in the food chain, this might
correspond to 30-year doses ranging up to several rems.
[p. 21]
3.28 On the basis of present information, the estimates made in
FRC Report No. 4, regarding the maximum concentrations of
radionuclides to be expected from fallout, the projected doses from
these nuclides, and the evaluation of the possible risks were es-
sentially correct. However, the time of the maximum contamina-
tion of the total diet is now expected to occur in 1964 instead of
1963. It is concluded that the predictions made in FRC Report No.
4 were substantially correct and the conclusions in that report still
apply.
[p. 22]
200
1961
1962
1963
1964
FIGURE 4.—Average concentration of radionuclides in milk samples from
Public Health Service pasteurized milk network (pc/liter).
[p. 23]
-------
1170
LEGAL COMPILATION—RADIATION
TABLE 3.—COMPARISON OF PREDICTED AND OBSERVED LEVELS OF RADIONUCLIDES
DEPOSITED AND IN THE U.S. DIET IN 1963*
"Wet"
"Dry"
Predicted
Observed Predicted
Observed
Deposition (me Sr*>/mi2):
Range 30-60 — 10-30 —
Most probable value 50 45 20 25
Milk:
Sr*>(pc/liter) 30 25 10 15
Sr" (pc/liter) 55 50 40 40
Cs'3' (pc/liter) 140 125 — 85
Wheat (pc Sr*>/ kg wheat) 250 220 — —
Flour (pc Sr*Vgm Ca) 40 40 — —
Total Diet (pc Sr«Vgm Ca) 50 30 35 10
New Bone (pc Sr«Vgm Ca) 12 7 92
Age 0-4 Bone (pc Srm/gm Ca) 25 5 J3 2
1 Except far bone, both predicted and observed values have been rounded to the nearest 5 units for
purposes of comparison since this is considered to be more in keeping with the reliability of the
estimates.
-J Calculated from the observed strontium-90 calcium ratio in the diet.
-------
GUIDELINES AND REPORTS
1171
I
Efl
0!
ft
01
0)
g
o
35
O
[p. 24]
-------
1172 LEGAL COMPILATION—RADIATION
TABLE 4.—AVERAGE STRONTIUM-90 CONTENT OF MILK IN THE U.S.*
[Picocuries strontinum-90 per liter of milk]
New York "Wet" Areas San Francisco "Dry" Areas
1959
1960 ...
1961 ...
1962 ...
1963
1964
1965
10
10
10
15
30
30
25
15
10
10
15
25
Observed
5
5
5
10
Predicted
10
5
10
5
5
10
15
' Predicted and observed values have been rounded to the nearest 5 units for purposes of comparison
since this is considered more in keeping with the reliability of the estimates.
[p. 26]
TABLE 5.—STRONTIUM-90 CONTENT OF WHEAT AND FLOUR IN THE U.S.*
[Picocuries per kilogram]
Year of
harvest
1959 .
1960 ...
1961
1962
1963 . .
Average from 9-15 States
weighted for production
Observed
Wheat Flour
50
25
25
... 85
220
10
5
10
15
40
Predicted
1964
1965
140
80
20
10
' Predicted and observed values have been rounded to the nearest 5 units for purposes of comparison
since this is considered more in keeping with the reliability of the estimates.
[p. 27]
-------
GUIDELINES AND REPORTS 1173
TABLE 6.—AVERAGE STRONTIUM-90 CONTENT OF U.S. TOTAL DIET*
[Picocuries strontium-90 per gram calcium]
Observed
1959
1960 .
1961
1962
1963
1964
1965
N.Y.C. ("Wet"
15
10
5
10
30
40
.... 30
Area) S.F. ("Dry" Area)
10
5
5
5
10
Predicted
20
15
1 Predicted and observed values have been rounded to the nearest 5 units for purposes of comparison
since this is considered more in keeping with the reliability of the estimates.
[p. 28]
TABLE 7.—AVERAGE STRONTIUM-90 CONTENT OF HUMAN BONE IN THE U.S.
[Picocuries strontium-90 per gram calcium]
Bone' observed (0-4 years old)
"Wet" Areas "Dry" Areas
1958 2.0 2.0
1959 2.7 2.2
1960 2.4 1.8
1961 2.6 0.9
1962 3.1 1.1
1963 5.0 1.9
Predicted (new bone 0-4 years old)
1964 10 5
1965 8 4
1 See paragraph 3.25.
[p. 29]
-------
1174 LEGAL COMPILATION—RADIATION
4.1g BACKGROUND MATERIAL FOR THE DEVELOPMENT
OF RADIATION PROTECTION STANDARDS, PROTECTIVE
ACTION GUIDES FOR STRONTIUM-89, STRONTIUM-90 AND
CESIUM-137, REPORT NO. 7, STAFF REPORT OF THE
FEDERAL RADIATION COUNCIL, MAY 1965
TABLE OF CONTENTS
Page
List of figures and tables iv
Summary 1
Section
I. Introduction 5
II. General Considerations 9
III. The Acute Localized Contaminating
Event 30
IV. Worldwide Contamination from
Stratospheric Fallout 40
[p. iii]
LIST OF FIGURES AND TABLES
FIGURE
1 Important Steps in the Transmission of Radioactive
Material Through the Food Chain to Man.
2 The Relative Concentration of Radionuclides in
Milk Following a Single Deposition on Pasture.
TABLE
1 Constants for Equation (1).
2 Tm, Am and Projected Intake by Man after an Acute
Contaminating Event Involving Pasture.
3 Intake Avoided Versus Time of Initiating Protec-
tive Action.
4 Relation Between Strontium-89 Intake Through Milk
and the Average Dose to Bone Marrow.
5 Relation Between Strontium-90 Intake Through Milk
and the Average Dose to Bone Marrow.
6 Relation Between Cesium-137 Intake Through Milk
and the Dose to Whole Body.
[p. iv]
SUMMARY
This report provides information and guidance for actions ap-
propriate to situations involving contamination of the environ-
ment by the radionuclides strontium-89, strontium-90, and
cesium-137. Two conditions of environmental contamination have
been examined: an acute localized contaminating event in which
prompt action may be necessary to avoid the exposure that would
-------
GUIDELINES AND REPORTS 1175
otherwise result; and a widespread, generally increasing, low-level
of contamination (from stratospheric fallout) that causes a con-
tinuous intake of radioactive materials by large numbers of people
for a period of years. Special consideration has been given to the
situation in the arctic region where, because of unusual ecological
conditions and food chains, some population groups are exposed
to levels higher than those in other parts of the United States.
In developing this report, the Staff of the Federal Radiation
Council has had the assistance of an advisory committee from the
National Academy of Sciences—National Research Council in re-
gard to the biological effects from irradiation by strontium-89,
strontium-90, and cesium-137; the assistance of an ad hoc panel of
scientists to provide data on biological, chemical, and physical fac-
tors involving radioactive contamination of the environment; and a
second panel to provide information on the dosimetry models re-
lated to these radionuclides.
The Acute Contaminating Event
The problem of evaluating when protective actions may be in-
dicated following an acute contaminating event has been sep-
arated into three categories. Category I is limited to the
transmission of radionuclides through pasture-cow-milk-man path-
way. If pasture is contaminated the concentration of radionu-
clides in milk would build up rapidly, reach a maximum in about a
week and then diminish by about half every two weeks as the re-
sult of weathering losses, new plant growth, and similar mech-
anisms. Protective actions initiated at approximately two weeks
following the contaminating event will avert 50 percent of the pro-
jected intake; actions initiated at approximately 1 week following
the event will avert 75 percent; and actions initiated within two
days will avert 90 percent.
Category II is concerned with the transmission of radionuclides
to man through dietary pathways other than that specified as Cat-
egory I during the first year following an acute contaminating
[P- 1]
event. This involves the use of feed crops for animals, including
dairy cattle, and plant products used directly for human consump-
tion. Immediate action to reduce the potential intake will not
usually be required because of the normal delay in the use of such
crops. However, an early decision will be required as to the need
for examination of harvested crops to determine the degree of
contamination before they enter normal marketing channels. Pro-
tective actions in Category II are not normally expected to be in-
dicated unless action was first needed in Category I.
-------
1176 LEGAL COMPILATION—RADIATION
Category III is primarily concerned with the long-term trans-
misson of strontium-90 through soil into plants in the years
following a contaminating event. Residual contamination of
cesium-137 may be a consideration for 1 to 2 years.
The benefits of a protective action taken in one category are
largely independent of whether action is taken in another. The
types of actions considered in the development of guidance in the
report include:
1. Altering production, processing or distribution practices affecting the
movement of radioactive contamination through the food chain and into the
human body. This action may include storage of food supplies and animal
feeds to allow for radioactive decay.
2. Diverting affected products to uses other than human consumption.
3. Condemning affected products.
The term "Protective Action Guide" has been defined as the pro-
jected absorbed dose to individuals in the general population that
warrants protective action following a contaminating event; and a
"protective action" as an action that will avert most of the ex-
posure that would otherwise occur.
It is generally impossible to predict total doses solely from the
degree of contamination of a particular crop. Therefore, the def-
inition of protective action is extended in this report so that if the
total projected dose from the use of all crops in Category II ex-
ceeds the Protective Action Guide, in order to make a substantial
reduction in the total dose, action should be initiated against those
crops that would make major contributions to that dose.
It is the purpose of the recommendations to discourage deliberate
introduction of contaminated food into supplies of uncontaminated
[p. 2]
food as an acceptable solution to environmental contamination.
Rather, it is recommended that if the contamination of a partic-
ular crop or dietary component is so high that it would not be
acceptable for local use, the crop or dietary component not
be considered acceptable for use in other areas to which it may be
transported.
The recommended Protective Action Guides are:
For Category I—A mean dose of 10 rads in the first year to the
bone marrow or whole body of individuals in the general popula-
tion; and provided further that the total dose resulting from Cat-
egory I not exceed 15 rads. For purposes of applying the guide,
the total dose from strontium-89 and cesium-137 is assumed to be
the same as the dose in the first year, whereas the total dose from
strontium-90 is assumed to be 5 times the dose in the first year.
For Category II—A mean dose of 5 rads in the first year to the
-------
GUIDELINES AND REPORTS 1177
bone marrow or whole body of individuals in the general popula-
tion. As an operational technique it is assumed that the guide will
be met effectively if the average dose to a suitable sample of the
population is one-third the PAG or approximately 3 rads for Cat-
egory I and 2 rads for Category II.
For Category HI—A Protective Action Guide is not recom-
mended. Rather, if it appears that annual doses to the bone mar-
row of individuals may exceed 0.5 rad or 0.2 rad to a suitable
sample of the populaiton, such situations shall be appropriately
evaluated.
Worldwide Contamination From Stratospheric Fallout
Studies of stratospheric fallout in the United States from past
testing were reported in FRC Report Nos. 4 and 6. On the basis
of this information, the Council concluded that the health risk
from radioactivity in food over the next several years would be
too small to justify protective actions to limit the intake of radio-
nuclides either by diet modifications or by altering the normal
distribution and use of foods, particularly milk and dairy products.
In Alaska, although the amount of fallout deposited per unit
area is about one-fifth as much as that deposited in the 30°-40°
latitude band, a combination of ecological conditions and specific
dietary habits of some Eskimos and Indians causes higher cesium
body burdens than are found in the conterminous United States.
Average body burdens of cesium-137 in these inhabitants were
[p. 3]
about three times as high in 1964 as they were in 1962. The
estimated whole body doses to these individuals in 1964 ranged
from about one-fourth to one-half of the numerical value of the
Radiation Protection Guide (RPG) for individuals in the general
population.
The practicality and value of protective actions against wide-
spread environmental contamination from stratospheric fallout is
limited because:
1. The condition to be alleviated is chronic exposure from long-term con-
tinuous intake (10 years or more).
2. A reduction in potential intake under these conditions requires basic
changes in long-term agricultural practices, food processing practices, dietary
habits, or all three.
3. The actions would have to be applied on a broad enough scale to reduce
the average quantity of radionuclides in the total diet from foods produced
throughout large areas or the entire country.
A Protective Action Guide is not recommended for this situation.
Rather, annual doses from fallout equal to or greater than the
-------
1178 LEGAL COMPILATION—RADIATION
numerical values of the RPG's can be used as an indication of
when there is a need for a careful evaluation of fallout exposures.
In view of these considerations it is recommended that surveil-
lance of the radionuclide content of food products contaminated
with worldwide fallout be continued at levels appropriate to the
situation. It is also recommended that surveillance and research
programs examining the special ecological situations in the arctic
region continue until future trends can be predicted with greater
confidence.
[P. 4]
SECTION I
INTRODUCTION
1.1 This background staff report provides information and guid-
ance for actions appropriate to situations involving contamination
of the environment by the radionuclides strontium-89, strontium-
90, and cesium-137. In certain circumstances, such as the unfore-
seen or uncontrollable dispersal of large quantities of radioactive
materials in the environment, the resulting exposure can be re-
duced only by protective actions taken against the radionuclides
in the environment. In these circumstances, changes in the normal
production, processing, distribution, and use of foods may be
required.
1.2 FRC Report Nos. 1 and 2 provide radiation protection guid-
ance for the control and regulation of the normal peacetime uses
of nuclear technology in which control is exercised primarily on
the design and use of the radiation source. The Radiation Pro-
tection Guides (RPG's) in those reports were developed as guide-
lines for the protection of radiation workers and the general
public against exposures which might result from routine uses of
ionizing radiation. In formulating those guides there was a judg-
ment, or balance, between the possible risks associated with a
particular radiation exposure and the reasons for allowing the
exposure.
1.3 An important factor in providing guides for any purpose is
the change in risk assigned to higher or lower doses and the cor-
responding effort to reduce them. Other factors influencing in-
formed opinion of where and why a particular balance should be
made include views regarding prevailing practices and the relative
importance of health risks in relation to economic, political, or
-------
GUIDELINES AND REPORTS 1179
other considerations of national welfare. With respect to environ-
mental levels of radioactivity, the RPG's reflect the residual risk
considered acceptable after engineering and procedural controls
have been applied at the source (i.e., place of origin) of the radio-
activity to limit releases to the environment. The numerical values
for these guides were placed as close to the annual dose from
natural background radiation as technical, economic, and opei'a-
tional considerations allowed.
1.4 Although radiation doses numerically equal to the RPG's
may impose a risk so small that they can be accepted each year for
a lifetime if there is significant benefit from the programs causing
the exposure, they do not and cannot establish a line that is safe
[p. 5]
on one side and unsafe on the other. Rather, some risk of injury
may exist at any level of dose and the risk continuously increases
with dose. Caution should be exercised in decisions to take pro-
tective actions in situations where projected doses are near the
numerical values of the RPG's, since the biological risks are so low
that the actions could have a net adverse rather than beneficial
effect on the public well-being.
1.5 In contrast to the guidance given in FRC Report Nos. 1 and
2, FRC Report No. 5 provided general guidance for the protection
of the population against exposure resulting from the accidental
release, or from the unforeseen appearance, of radioactive mate-
rials in the environment. Specific guidance, including a numerical
value for the Protective Action Guide (PAG), was provided for
iodine-131. The PAG represents a consensus as to when, under
the conditions considered most likely to occur, intervention is in-
dicated to avoid radiation exposure that would otherwise result
from transient environmental contamination. This consensus in-
volves health, economic, sociologic and political factors for which
the relative values are different than for the RPG. For the PAG
these factors may include agricultural policies, the known feasi-
bility of protective actions, related health impacts and similar
considerations involved in the national interest.
Scope
1.6 This report provides background material used in the de-
velopment of guidance for Federal agencies in planning activities
to protect the population from strontium-89, strontium-90, and
cesium-137 for certain situations in which these radionuclides may
appear in the environment. A basic assumption in the develop-
ment of the guidance is that a condition requiring protective
-------
1180 LEGAL COMPILATION—RADIATION
action is unusual and should not be expected to occur frequently.
Two conditions of environmental contamination have been exam-
ined: An acute localized contaminating event in which prompt
action may be necessary to avoid the exposure that would other-
wise result; and a widespread, generally increasing, low-level of
contamination (from stratospheric fallout) that would cause a
continuous intake of radioactive nuclides by large numbers of
people for a period of years.
1.7 Exposure of the general population to radioactive materials
in the environment may result from external irradiation, inhala-
tion, and ingestion of such materials. For most environmental
situations, ingestion will produce the greatest absorbed dose. In-
gestion of radioactive materials may be limited by protective
[p. 6]
actions affecting the normal production, processing, distribution,
and use of food. As in FRC Report No. 5, only ingestion is con-
sidered in the present report. Only the transmission pathway
from pasture through fluid milk to man was considered important
for iodine-131. In this report it is necessary to consider the
additional routes through animal feed crops, human food crops,
and root uptake due primarily to the longer radioactive half lives
of the nuclides under consideration. The report also considers the
situation in the arctic region where, because of unusual ecological
conditions and food chains, some population groups are exposed
to levels higher than those in other parts of the United States.
1.8 The numerical values of absorbed doses specified as guides
for an acute contaminating event are not intended to authorize
deliberate releases expected to result in absorbed doses of these
magnitudes, nor do they have any relevance to civil defense
applications.
Preparation of Staff Report
1.9 The staff reviewed the applicable literature on the biological
aspects of exposure to the radionuclides of interest in this report.
The literature included reports from such groups as the National
Council on Radiation Protection and Measurements, International
Commission on Radiological Protection, United Nations Scientific
Committee on the Effects of Atomic Radiation (UNSCEAR),
International Atomic Energy Agency, and the Committee on Pro-
tection Against Ionizing Radiations of the United Kingdom's
Medical Research Council. In addition, a review has been made
of the practices and procedures in the agricultural and food proc-
essing fields that might be useful in reducing potential radionuclide
intake.
-------
GUIDELINES AND REPORTS 1181
1.10 Upon invitation from the Federal Radiation Council, the
National Academy of Sciences—National Research Council (NAS-
NRC) selected a committee of experts to prepare a summary of
the biological effects to be expected in man from irradiation by
strontium-89, strontium-90, and cesium-137. The committee's
findings have been helpful to the Council in developing guidance
presented in this report.
1.11 The staff also convened two ad hoc panels of scientists
actively engaged in research projects involving strontium and
cesium; one panel to provide data on the biological, chemical and
physical factors involving radioactive contamination of pasture,
milk, and other foods; and the second panel to provide information
[p. 7]
on the dosimetric relations for these radionuclides. Applicable in-
formation provided by these panels has been incorporated into this
report.
[P. 8]
SECTION II
GENERAL CONSIDERATIONS
Origin and Distribution of Radioactive Materials in the
Environment
2.1 The origin and distribution of radioactive materials injected
into the atmosphere and their transport mechanisms through the
environment to man have been studied intensively both nationally
and internationally for the past decade in connection with the
atmospheric testing of nuclear weapons. The past and anticipated
concentrations of radioactive materials in the environment from
weapons testing through 1962 have been studied and evaluated
by the Council in its Report Nos. 3, 4, and 6.
2.2 When radioactive materials are released to the atmosphere
at ground level, as would generally be the case from an industrial
accident, dispersion in the troposphere is limited in extent. In this
case, a single incident may cause deposition of high concentrations
of radioactive materials within limited areas. Similar localized
high-level deposition might also occur with tropospheric fallout
deposited under unusual meteorological conditions.
2.3 Material injected into the stratosphere by nuclear weapons
tests eventually descends to the troposphere from which it is de-
posited on the earth's surface. During storage in the stratosphere,
-------
1182 LEGAL COMPILATION—RADIATION
short-lived radionuclides decay essentially to zero. Long-lived
radionuclides that find their way to the troposphere deposit rela-
tively uniformly on a regional basis, although the quantities vary
with latitude and with rainfall. A somewhat similar distribution
pattern of short-lived radioactive material such as iodine-131 has
been observed in the United States for the tropospheric distribu-
tion of debris from tests conducted outside the United States.
2.4 Thus, from past experience one can distinguish two limiting
situations of environmental deposition. The first situation (see
Section III) can be characterized as a high level of contamination
that is limited in time and geographical area. This situation is
generally identified with an accidental release of material from an
industrial source or as the result of a localized high-level con-
tamination resulting from deposition of tropospheric fallout dur-
ing unusual meteorological conditions. The second situation (see
[P. 9]
Section IV) can be characterized as a geographically widespread,
low level contamination, resulting from relatively uniform deposi-
tion of radioactive materials originally injected into the trop-
osphere or stratosphere. This situation is generally identified with
nuclear explosions in the atmosphere. There may be conditions
which fall between these two situations. However, for these inter-
mediate cases, it is difficult to predict the relative magnitude of
such factors as areas involved, crops affected, and the population
at risk.
Radioactive Nuclides of Interest
2.5 Although nuclear fission produces many nuclides, most of
which are radioactive, their chemical and physical properties are
such that few of them are of biological concern as potential radio-
active contaminants of food. Some of these radionuclides have
such short radioactive half lives that their radioactive decay to
stable nuclides is essentially complete before the food is consumed.
Those of principal interest are isotopes of elements readily utilized
by vegetation or animals and of sufficiently long radioactive half
lives that much of their radioactivity will not have disappeared
before the food is consumed.
2.6 The relative importance of different radionuclides may de-
pend on additional factors such as: the time that elapses between
fission and the release of fission products to the environment;
chemical or physical separation or fractionation; conditions of re-
lease; and season of the year. For example, in unseparated fission
products only a few days of age, the properties of iodine make it
the most important radionuclide; in fission products aged a few
weeks the longer-lived strontium-89, strontium-90, and cesium-137
-------
GUIDELINES AND EEPORTS 1183
are the nuclides of importance. Studies of possible types of re-
lease have lead to the conclusion that events requiring protective
actions are most likely to involve iodine-131.
The Transmission Pathways
2.7 The transmission pathways of radioactive material from the
atmosphere through the food chain to man are shown in Figure 1.
The radioactive material is scavenged from the atmosphere by
meteorological processes, particularly rain. The most serious con-
tamination problems would arise from direct deposition of the
radionuclides on animal feed crops or on food crops directly con-
sumed by man. Following the initial deposition on vegetation the
radioactive materials tend to be removed by various processes,
such as being washed off by rain or being blown off by the wind.
The extent to which such removal occurs depends on a number of
[p. 10]
-------
1184
LEGAL COMPILATION—RADIATION
ATMOSPHERE
FOOD CROPS
PASTURAGE
FEED CROPS
MEAT AND
MEAT PRODUCTS
ANIMALS
FRESH
FLUID MILK
MAN
PROCESSED
MILK PRODUCTS
FIGURE 1.—Important steps in the transmission of radioactive material
through the food chain to man.
[p. 11]
considerations, including particle size and chemical properties of
the material deposited and environmental or biological factors.
2.8 The time of deposition relative to the various stages in the
plant growth cycle is a major factor affecting the projected intake
by man resulting from a given deposition. Much less radioactive
-------
GUIDELINES AND REPORTS 1185
material will enter the food chain if the deposition occurs during
a period when there is less vegetation or when animals are not on
pasture than if the deposition immediately precedes the harvest of
a crop. With increasing time between deposition and harvest the
transmission of radioactive materials through the food chain would
diminish as a result of dilution by new plant growth, removal by
weathering and decay, and in some instances by fixation in the soil.
2.9 As seen in Figure 1, man's ingestion of radioactive material
may result from contaminated food crops, from contaminated meat
or meat products, and from contaminated milk or milk products.
The relative importance of the various pathways of intake depends
on the radioactive half lives of the radionuclides, the rate and
routes by which they pass through the transmission chain, and the
dietary habits of the population.
2.10 The immediate and usually the most significant transmis-
sion of all these radionuclides will occur through the pasture-cow-
milk-man pathway. Because of the various types of plant losses
the immediate phase will ordinarily not be of importance after the
first 100 days following deposition.
2.11 A later transmission of radionuclides through milk may
occur from use of stored feed if this feed was contaminated in the
field at the time of the deposition. The relative importance of this
pathway may vary greatly due to differences in time between de-
position and harvest, the portion of the feed supply contaminated,
and the use of the feed supply.
2.12 Foods other than milk may be contaminated to some extent
as a result of deposition of radionuclides on food crops or on pas-
ture and feed crops used for meat animals. The variables involved
are similar to those of the transmission to milk through stored
feed. Cesium-137 would usually be the only significant contam-
inant present in meat.
2.13 After the first year there may be a residual problem result-
[p. 12]
ing from deposition on soil and subsequent root uptake. This prob-
lem would generally concern only strontium-90. Strontium-89
would be essentially removed by radioactive decay and cesium-137
in the soil is generally unavailable to plants.
2.14 Once the radioactive material is ingested by man, the up-
take depends upon the chemical properties of the elements and the
physiology of the organ involved. Thus, iodine-131 tends to con-
centrate in the thyroid and strontium-89 and -90 in the bone, while
cesium-137 is more-or-less uniformly distributed throughout the
body.
-------
1186 LEGAL COMPILATION—RADIATION
Concentrations of Radionuclides in Milk and Projected Intake by
Man Following a Contaminating Event
2.15 The ad hoc panel that provided data on the factors involv-
ing radioactive contamination of pasture, milk and other foods
following a postulated acute deposition, used the following as-
sumptions: (1) physical and chemical properties of the radio-
nuclides were the same as found in worldwide fallout, (2)
deposition time was short, (3) deposition was on pasture for dairy
cows, and (4) the background and previous cumulative soil con-
tamination levels were negligible. Animal tracer and surveillance
network data were used to derive the relationships between con-
centrations of strontium-89, strontium-90, and cesium-137 in milk
and the projected intakes by man.
2.16 Three factors are involved in estimating concentrations of
radionuclides in milk after a contaminating event: (1) the secre-
tion rate of the radionuclides into milk following ingestion of a
constant daily intake of contaminated vegetation by the cow, (2)
reduction of the pasture contamination by weathering and dilution
by plant growth, and (3) radioactive decay. When all of these
factors are considered, the concentrations of strontium-89, stron-
tium-90, and cesium-137 in milk, as a function of the cow's intake,
are described by the equation:
A = (cekll) (l-e-^1) (e-k3') (e-k4l) (1)
A is the radionuclide concentration in milk; c, kl, k2, I[3, and k4
are constants for a given radionuclide, and t is the time in days
after deposition. The first two terms of the equation describe the
radionuclide concentration in milk resulting from a constant intake
by the cow. The third term describes the rate of loss from vegeta-
tion, and the fourth term describes the radioactive decay. This
[p. 13]
equation is illustrated in Figure 2 as the radionuclide concentration
in milk at any time, expressed as a fraction of the maximum con-
centration (Am).
2.17 In order to derive the constants (Table 1) for the equation
it was necessary to relate the radionuclide concentration in milk to
the cow's radionuclide intake during the first day after contamina-
tion of the pasture, but knowledge of the cow's intake is not needed
to apply the equation. The secretion rate of radionuclides into
milk following deposition was estimated from animal experiments
in which there was a constant daily intake of the radionuclides by
each cow. The rate of loss from vegetation was estimated from
surveillance data and from experimental field work. There is a
-------
GUIDELINES AND REPORTS 1187
range of measured values for the effective half-time of the radio-
nuclides on grass, most of which are close to 14 days. This value
has been selected for use in this report. The effect of radioactive
decay in the case of strontium-90 and cesium-137 can be neglected
because of the short grazing season compared to the long half lives
of these radionuclides.
TABLE 1.—CONSTANTS FOR EQUATION (1)
Strontium-89 Strontium-90 Cesium-137
c (nCi/1)
(nCi/day)
k (days-1)
k (days-1)
k (days-1)
k (days - ')
0.001
0 008
0.26
0.05
0.014
0001
0 008
0 26
0 05
NA
0 013
0 01
0 41
0.05
NA
NA=Not applicable.
nCi=nanocurie=l X 10-' curie.
2.18 The values for Tm> Am normalized to 1 nanocurie per liter of milk, and the projected intake by
man in nanocunes assuming a daily consumption of 1 liter of milk, are listed in Table 2.
2.18 The values for Tm, Am normalized to 1 nanocurie per liter
of milk, and the projected intake by man in nanocuries assuming
a daily consumption of 1 liter of milk, are listed in Table 2.
[P. 14]
-------
1188
LEGAL COMPILATION—RADIATION
—_ A,
20
40 60 80 100
TIME AFTER DEPOSITION (days)
120
*T,,,=time maximum concentration occurs.
FIGURE 2.—The relative concentration of radionuclides in milk following
a single deposition on pasture.
[p. 15]
2.19 The reduction of radionuclide concentration in milk after
changing cows from pasture to an uncontaminated feed source has
been estimated from the exponential decline of radionuclide con-
centration in milk following a single intake of a tracer by cows.
After the shift to uncontaminated feed, and assuming a constant
daily consumption of milk by man, it has been calculated that the
remaining intake will equal 2.9, 3.4, and 5.1 times the daily intake
of strontium-89, strontium-90, and cesium-137, respectively, at the
time of the shift. These relations make it possible to estimate
when the shift has to be made in order to avoid various percentages
of the total projected intake by man. The results are summarized
in Table 3.
-------
GUIDELINES AND REPORTS 1189
TABLE 2.—Tm, Am AND PROJECTED INTAKE BY MAN AFTER AN
ACUTE CONTAMINATING EVENT INVOLVING PASTURE
T (days) . .
A (nCi/ liter)
Projected Intake (nCi)
Strontium-89
7
I
27
Strontium-90
7
1
33
Cesium-137
6
1
32
TABLE 3.—INTAKE AVOIDED VERSUS TIME OF INITIATING PROTECTIVE ACTION
Projected Intake S'trontium-89 Strontium-90 Cesium-137
Avoided (%) (days)* (days)* (days)*
50 13 17 14
75 6 7 5
90 2 2 2
*Days after the initial contamination of pasture at which cows would have to be shifted to uncon-
taminated feed.
[p. 16]
Biological Risk Considerations
2.20 The possible biological effects that might follow irradiation
of human tissue under differing conditions have been previously
reviewed by the FRC in Report Nos. 1 and 2, and more recently
by the UNSCEAR (1962 and 1964). In 1964 the Federal Radia-
tion Council asked the National Academy of Sciences—National
Research Council to prepare a report on the effects to be expected
in man from irradiation by internally deposited strontium-89,
strontium-90, and cesium-137 for doses of 25 rads or less from a
single contaminating event.
2.21 The Academy in turn established a committee of experts
to evaluate the possible effects of these radionuclides in man. The
committee considered the particular metabolic properties of these
radionuclides, the known effects of irradiation from these and
other internally deposited radionuclides, and from external sources.
The committee gave particular consideration to the effects that
might result from the short-term uptake of any one of these radio-
nuclides by a small fraction of the population.
2.22 The possible risk to segments of a population with a typical
distribution of adults, including pregnant women, as well as of
children and infants has been examined. The population at risk
from local contamination of the environment will be small. In a
population with a typical distribution of ages about 50 percent are
age 30 or younger, about 10 percent will be of age 4 or younger,
and about 2 percent are pregnant women.
2.23 In regard to hereditary effects, it is assumed that any in-
crease in radiation exposure to the genetic cells causes some in-
-------
1190 LEGAL COMPILATION—RADIATION
crease in the mutation rate. The hereditary load induced in a
population is proportional to the average dose to the entire popula-
tion. However, the dose to the individual must also be considered.
The NAS-NRC Committee on Genetic Effects of Atomic Radiation
expressed the opinion in 1956 that the chance of genetic damage
of such a nature as to be expressed in an individual's immediate
family would be acceptably small if the dose to the individual was
less than 50 rads in 30 years. This opinion was reaffirmed in 1964,
and it was concluded that genetic considerations are not limiting
under circumstances for which protective action may be needed
provided that the exposed population is small and the dose to an
individual is small compared to 50 rads (NAS Report to FRC,
1964, par. 4.10).
[P. 17]
2.24 Available estimates of the risk of somatic injury following
irradiation have been obtained largely from high dose rates (a
few rads or greater per minute), high radiation doses (exceeding
100 rads), or both. These estimates can be considered valid only
for the conditions of irradiation for which they were obtained,
since there is evidence indicating that the effect of an irradiation
depends on both the total dose and the dose rate.
2.25 It has not been established whether internal emitters se-
lectively deposited in bone (bone-seekers) are leukemogenic in
man. In addition the specific sites of leukemogenesis, particularly
as a function of age, are essentially unknown. However, for the
purposes of this report, bone marrow is considered to be the most
significant tissue from the standpoint of susceptibility to harmful
effects of irradiation.
2.26 Evidence based largely on the survivors of Hiroshima and
Nagasaki indicates that, if a population of a million people were
to receive a radiation dose of 100 to 500 rads, the average increase
in the incidence of leukemia over a period of about 15 years would
be from one to two cases per year per rad. (NAS Report to FRC,
1964, par. 5.15; UNSCEAR, 1964, Appendix B, par. 30). An ap-
proximately equal number of other neoplasms attributed to the
irradiation was found in the same population (UNSCEAR, 1964,
Appendix B, par. 179) giving a total increase of 2 to 4 cases per
year per million persons per rad averaged over the same number
of years.
2.27 An association between antenatal exposure and an in-
creased incidence of cancer in childhood has also been reported.
This has been related to single exposures (essentially whole body)
to the fetus that may have been as low as 2 to 5 R (NAS Report
to FRC, 1964, par. 5.10). The increased incidence of leukemia and
-------
GUIDELINES AND REPORTS 1191
total neoplasms calculated on the assumption of linearity was 4 to
10 and 8 to 20 cases per year, respectively, per million fetuses ex-
posed per rad up to the age of 10 years (NAS Report to FRC,
1964, par. 5.11). The risk following antenatal exposure at high
dose rate was accordingly estimated to be about 2 to 5 times the
risk per rad following postnatal irradiation.
2.27 These estimates of radiation risk cannot be corrected to
account for the effects of differences in dose rate and dose dis-
tribution. For comparable total doses the dose rate from stron-
tium and cesium under the conditions of present interest is about
10~5 to 10~6 of the dose rates associated with the estimates of radi-
[P. 18]
ation risk in antenatal exposure. Since the strontium nuclides
irradiate only that portion of the tissue adjacent to the sites of
deposition in the skeleton, the dose distributions are very different
from those for which there are risk estimates.
2.29 However, there is evidence from radiobiological exper-
iments indicating that somatic cells, even in the embryo, and
genetic cells generally sustain less injury from a given dose if
irradiated at low dose rates than if irradiated at high dose rates.
For example, genetic studies on mice led to the estimate that when
both parents are irradiated at low dose rates, the effectiveness of
irradiation in producing mutations may be as little as one-sixth
that of the same dose given at high dose rates (FRC Report No. 3,
p. 7). Similar observations on the influence of dose rate have
been made for radiation-induced leukemogenesis in animals (NAS
Report to FRC, 1964, par. 5.17). Hence, the magnitude of the
dose rate effect may be considered to be in the same range as the
reported difference in radiation sensitivity between antenatal and
postnatal populations exposed at high dose rates. From these
considerations it is estimated that the upper limit of risk per rad
related to antenatal exposure under the conditions of interest (low
dose rate) will be no greater than the risk heretofore related to
postnatal exposure to the same dose at high dose rates.
Dosimetry Considerations
2.30 The small organ size of infants results in a relatively larger
dose per unit intake of radioactive material than for older age
groups. Also, from the preceding discussion, the fetus is more
susceptible to injury than infants or adults per unit dose. For
these reasons special consideration has been given to antenatal and
infant exposure.
Strontium
2.31 The metabolism of strontium is linked to the metabolism
-------
1192 LEGAL COMPILATION—RADIATION
of calcium in a complex way. The body preferentially absorbs
calcium and preferentially excretes strontium. However, stron-
tium and calcium are incorporated into new bone in the same ratio
as they exist in blood. It is not known whether the biological risk
from radioactive strontium depends upon the dose to bone marrow
adjacent to the sites where strontium is incorporated in the skele-
ton, or upon the mean dose to all the bone marrow in the skeleton.
Under the linear hypothesis the mean dose to all bone marrow is
[p. 19]
the dose of interest for the evaluation of biological risk, and is the
one used in this report.
2.32 The radiation dose to mineral bone that would result from
the ingestion of radioactive strontium from the diet depends on the
fraction of ingested strontium reaching bone and the length of
time it remains there. Inadequate knowledge of the way stron-
tium may be initially distributed in the skeleton makes a calcula-
tion of radiation dose, particularly to bone marrow, very difficult.
If uniformly distributed throughout the mineral bone of the adult,
1 nanocurie of strontium-89 per gram of calcium would result in a
dose of 0.3 rad to mineral bone (derived from UNSCEAR, 1962,
Annex F, par. 52, p. 356). One nanocurie of strontium-90 per
gram calcium uniformly distributed in adult bone would result in
a dose of 2.7 rads in a year (UNSCEAR, 1962, Annex F, par. 29,
p. 353). The dose to mineral bone of the fetus and infant may be
about one-half the adult values because the young skeleton has less
mineral per gram of bone, and because the young skeleton absorbs
less of the available beta energy (Some Aspects of Internal Ir-
radiation, Pergamon Press, Oxford 1962, p. 447).
2.33 The estimation of the dose to bone marrow resulting from
the incorporation of radioactive strontium in the surrounding
mineral bone is a complex problem. The energies of the beta par-
ticles from the radioactive decay of strontium are distributed over
a broad spectrum, and for each energy a specific range of the
particle in bone, soft tissue, or in a combination of the two must
be considered. The dose to bone marrow from strontium-89 and
strontium-90 uniformly distributed in the adult skeleton has been
estimated to be about one-fifth the calculated dose to mineral bone
for strontium-89 and about one-fourth the dose to mineral bone
from strontium-90 (UNSCEAR, 1962). The Federal Radiation
Council used a value of one-third for both nuclides in FRC Report
No. 2.
2.34 Although the lower density of mineralization in the infant
and fetal skeleton results in a lower dose to mineral bone than the
dose from the same concentration of strontium in the adult skel-
-------
GUIDELINES AND REPORTS 1193
eton, the resulting dose to bone marrow of the infant or fetus will
be relatively higher for the same reason. Therefore, one-third
of the dose that would be calculated for mineral bone per unit of
strontium in the adult skeleton is also a reasonable estimate of the
dose from the same concentration to bone marrow of the fetus
and infant. The calculations in this report accordingly assume
that for estimating radiation dose to the bone marrow of a fetus or
[p. 20]
infant from radioactive strontium in the skeleton (1) the radio-
active strontium is uniformly distributed in the mineral bone, (2)
a concentration of 1 nanocurie strontium-89 per gram calcium in
the skeleton will give a total dose of 0.1 rad to bone marrow, and
(3) a concentration of 1 nanocurie strontium-90 per gram calcium
in the skeleton will give a dose of 0.9 rad in one year to bone mar-
row. With present information, these dose conversion factors
give the best available estimates of the biologically important dose,
i.e., the average dose to bone marrow following short-term intake
of radioactive strontium.
2.35 The relationship of strontium and calcium in children's
bones compared to the strontium to calcium ratio in the diet is
based on results obtained from measurements made on strontium-
90 from fallout. The proportion of radioactive strontium incor-
porated into the skeleton from the diet mainly involves two factors:
first, discrimination by the body against strontium in favor of
calcium; and second, the amount of calcium with its associated
strontium which is incorporated into the skeleton each day by the
formation of new bone.
2.36 The first factor, discrimination between strontium and cal-
cium in the passage of these elements from the diet to a given
tissue in the body, is usually expressed as the Observed Ratio
(OR). The OR relates the ratio of strontium to calcium that
exists at equilibrium in a given component of the body to the ratio
of strontium ta calcium in the diet. If the body component is the
bone, then:
rvr> u /j- 4. Sr/Cainbone /0.
OR bone/diet = — (2)
Sr/Ca in diet
The OR, fetal bone to mother's diet is estimated to be about 0.1.
The OR, bone to diet changes from about 1 at birth, to about 0.5
at 6 months to 1 year, and to about 0.25 shortly thereafter (NAS
Report to FRC, 1964, par. 3.14). An OR of 0.35 has been selected
as the most representative value for the age group of interest
(i.e., 6 months to 2 years).
-------
1194 LEGAL COMPILATION—RADIATION
2.37 The second factor is related to the sum of the calcium in-
volved in skeletal growth (net accretion) plus the quantity of
calcium in the existing skeleton that is replaced (turnover).
Mitchell, et al. (J. Biol. Chem. 158, 625, 1945) have estimated the
net annual calcium accretion from birth to 20 years, after which
skeletal growth ceases. The quantity of calcium in the skeleton
at birth and at ages 1 and 2 has been estimated to be 28, 100, and
150 grams, respectively. The estimated net accretion of calcium
[p. 21]
is 28 grams in the fetal period, 72 grams during the first year of
life, and 50 grams in the second year of life. The bone mineral
turnover rate during the first two years of life is estimated to be
about 50 percent per year (NAS Report to FRC, 1964, par. 3.12).
The turnover rate decreases to an adult value of about 1 percent
per year in the shafts of long bones and 10 percent in cancellous
bone.
2.38 The radiation dose delivered to the skeleton during the first
year following a contaminating event varies with the length of
time the diet is contaminated. Estimates have been made for a
contaminating event that would result in a total intake of one
microcurie of strontium-89 or strontium-90 in 100 days, the period
of interest for the transmission of these radionuclides through the
pasture-cow-milk-man pathway. Assuming that the typical cal-
cium intake is about 1 gram per day, the radioactive strontium
intake would then be associated with 100 grams of calcium. Thus,
an intake of one microcurie of radioactive strontium in 100 days
would result in an average dietary level of 10 nanocuries of radio-
active strontium per gram of calcium.
2.39 For estimating dose following the ingestion of radioactive
strontium, the ad hoc dosimetry group recommended a model
embodying: formation of a specified amount of new bone per day;
further resorption and remodeling of a specified amount of exist-
ing bone per day; and use of the OR to relate the strontium to
calcium ratio in the diet to that in bone. A dynamic model which
simulates incremental changes in skeletal strontium on a day to
day basis was developed utilizing computer techniques. Evalua-
tion of the results from the computer model indicated that a less
refined approach using strontium diet levels averaged for the pe-
riod of intake and other simplifying assumptions regarding net
calcium accretion and bone turnover would provide comparable
estimates of dose.
2.40 An estimate of the dose to bone marrow from radioactive
strontium in the diet can be reduced to two considerations:
-------
GUIDELINES AND REPORTS 1195
1. An estimate of the average strontium to calcium ratio in the skeleton
from average dietary levels for a short-term intake.
2. The use of a dose conversion factor to convert the skeletal concentrations
of strontium into dose to the bone marrow. The average strontium to calcium
[p- 22]
ratio (Ra) in the skeleton may be estimated from:
Ra = Rd X OR X F (3)
where:
Rd = strontium to calcium ratio in the diet averaged over the
period of intake.
OR = Observed Ratio.
F = Fraction of skeletal calcium incorporated by accretion
and turnover during the period of intake.
An estimate of dose (D) can be calculated by:
D = Ra X Dose Conversion Factor (4)
Application of the appropriate dose conversion factors from par.
2.34 will give the total dose from strontium-89 or the dose in one
year from strontium-90, which would result from the calculated
average skeletal strontium to calcium ratios.
2.41 For the antenatal period the maximum strontium burden
of the developing skeleton would result when the 100 day intake
coincides with the third trimester, i.e., when essentially all of the
mineralization of the fetal skeleton occurs. Thus F would be 1.0.
Using an R(1 of 10 nanocuries of radioactive strontium (denoted as
Sr* in the equations) per gram of calcium in the mother's diet and
an OR of 0.1 for mother's diet to fetal bone, the average strontium
to calcium ratio in the fetal skeleton would be:
Ra = 10 X 0.1 X 1.0 = 1.0
gCa
2.42 For the infant one to two years old, the fraction F must
be estimated from the annual net accretion and turnover. The net
accretion during the second year of life is estimated to be about
50 grams of calcium. The turnover is estimated to be an addi-
tional 50 grams of calcium during this year. The fraction of
calcium in the skeleton that is incorporated during the 100 day
intake is:
F = 5P_LJ>0 x 100 = Olg
150 365
Using an Rd of 10 nanocuries of strontium per gram of calcium in
-------
1196 LEGAL COMPILATION—RADIATION
the diet and an OR of 0.35, the average strontium to calcium ratio
[p. 23]
in the infant skeleton would be:
Ra = 10 X 0.35 X 0.18 = °-65nCiSr*
gCa
Strontium-89
2.43 The total dose resulting from the 100 day intake of stron-
tium-89 can be calculated using the dose conversion factor pre-
viously given. A concentration of 1 nanocurie strontium-89 per
gram of calcium in the skeleton would give a total dose of 0.1 rad
to bone marrow. For the two cases presented the doses would be:
Fetus: D = 1.0 X 0.1 = 0.1 rad
Infant: D = 0.65 X 0.1 = 0.065 rad
Thus the resulting total dose to the bone marrow of the infant is
estimated to be about two-thirds of the total dose to the bone
marrow of the fetus for the same intake by the infant and the
pregnant mother. This difference is less than the uncertainties
inherent in the estimate, and is not considered significant.
Strontium-90
2.44 Using the relationship that one nanocurie of strontium-90
per gram of calcium in the skeleton will give a dose of 0.9 rad in
one year to the bone marrow, the doses from strontium-90 for the
two cases presented would be:
Fetus: D = 1.0 X 0.9 = 0.9 rad in one year
Infant: D = 0.65 X 0.9 = 0.6 rad in one year
2.45 Since one trimester is about one-fourth of a year, the dose
to the fetus before birth would be about one-fourth the dose in one
year estimated from the strontium-90 to calcium ratio in the fetal
skeleton, or approximately 0.2 rad. The strontium-90 burden at
birth would be one nanocurie of strontium-90 per gram of calcium
times 28 grams of calcium or 28 nanocuries. With a bone turnover
rate of 50 percent per year there would be 28 X 0.5 = 14 nano-
curies strontium-90 per 100 grams calcium in the skeleton at age 1,
and 7 nanocuries strontium-90 per 150 grams of calcium at age 2.
These concentrations of strontium-90 give dose rates of 0.1 and
0.04 rad per year, respectively. Computer analysis led to the
estimate that the total (70 year) dose from a short-term intake of
[P. 24]
strontium-90 would be about 5 times the dose in the year when the
infant is age 1. Assuming that the dose in a year can be reason-
-------
GUIDELINES AND REPORTS 1197
ably approximated by the average of the dose rates at the begin-
ning and end of the year, the projected total dose to bone marrow
of an individual whose mother had an intake of 1 microcurie of
strontium-90 during the last 3 months of pregnancy would be:
^ A o , f°-9 + O-1! , c f0-1 + °-04l 11 i 4- 4- i A
D = 0.2 + +5 = 1.1 rads, total dose
L 2 J L 2 J
The total bone marrow dose for the infant would be:
D = 0.6 X 5 = 3 rads, total dose
It is concluded that for an identical intake over 100 days by the
infant and by the pregnant woman the total dose to the infant
would be approximately three times the total dose to the individual
exposed as a fetus.
2.46 In view of the considerations discussed in the previous
paragraphs, the estimates of projected doses to individuals in the
general population are based on a dose of 0.1 rad to bone marrow
following the ingestion of 1 microcurie of strontium-89 associated
with 100 grams of calcium, and a dose of 0.6 rad in the first year
with a total dose of 3 rads to bone marrow following the ingestion
of 1 microcurie of strontium-90 associated with 100 grams of
calcium.
Cesium-137
2.47 Cesium-137 is an alkali metal which is chemically and
metabolically similar to potassium. Its distribution after inges-
tion is relatively uniform throughout the body resulting in irra-
diation of the whole body, including bone marrow. It is eliminated
from the body at a rate which may be expressed in terms of the
biological half life. This is the time required for the body to
eliminate one-half of an initial body burden of cesium.
2.48 The dose resulting from a given intake of cesium-137 is
directly proportional to the biological half life and inversely pro-
portional to the lean body mass. A review of the literature in-
dicates that the biological half life ranges from about 60 to 180
days in adults. The value for normal adults in the general pop-
ulation is estimated to be about 100 days (NAS Report to FRC,
1964, par. 2.12). The data for persons younger than 25 years
suggest that the biological half life before maturity may be a
function of age. Biological half lives of about 20 days or less have
[p. 25]
been reported for infants. For this report a value of 30 days is
used as the biological half life of cesium-137 in infants.
2.49 The radiation dose per microcurie of cesium-137 ingested
-------
1198 LEGAL COMPILATION—RADIATION
may be approximately related to the body size and the biological
half life by the formula:
D = — X 0.03 X 1.44 TB (5)
W
where:
D = the total dose in rads
I = the total intake in microcuries of cesium-137
W = the body weight in kilograms
0.03 = kilogram rads per microcurie day (based on the absorption
of 0.59 MeV per disintegration).
TB = the biological half life in days
2.50 An infant weighing 10 kg (about 22 pounds) and ingesting
1 microcurie of cesium-137 would receive a dose of 0.13 rad. An
adult weighing 70 kg and ingesting 1 microcurie of cesium-137
would receive a dose of 0.06 rad. The dose rate to the fetus is
considered to be the same as the dose rate to the mother. There-
fore, for equal intakes of cesium-137 the dose to the infant would
be about twice the maximum dose to the fetus. Most of the dose
from a short-term intake of cesium-137 would be received in one
year. A value of 0.13 rad following the ingestion of 1 microcurie
of cesium-137 is used to estimate projected doses to the general
population.
Protective Actions and Guides
2.51 As stated in FRC Report No. 5, a protective action is an
action or measure taken to avoid most of the exposure to radiation
that would occur from future ingestion of foods contaminated with
radioactive materials. In the present report the concept of pro-
tective action must be extended in its application because the
longer half lives of strontium-90 and cesium-137 may lead to a
more persistant contamination of a number of food and animal
feed crops. Therefore, in order to achieve a substantial reduction
[p. 26]
in the total dose, it is necessary to consider protective actions
against those animal feed crops or food crops that would make
major contributions to that dose.
2.52 Some basic considerations in the development of protective
actions and guides are:
1. The occurrence of an acute contaminating event which will require pro-
tective action is considered to be so infrequent that it is unlikely that the same
individual will be exposed to more than one event.
2. Exposure to the public from radionuclides in the environment is directly
-------
GUIDELINES AND REPORTS 1199
related to the concentration of the radionuclides in food supplies and the length
of time (weeks, months, or years) over which unusual exposures would be
expected to occur. The need for protective actions is generally independent
of the source of contamination.
3. The substitution of food or feeds of lower radionuclide content for con-
taminated products is both effective and practicable.
4. The potential intake of radionuclides by individuals in the general public
from radionuclides in the environment can be reduced whenever modifications
in the normal production, processing, distribution, or dietary practices are
considered to be less objectionable than the radiation risk that would otherwise
have to be accepted.
5. Protective actions, by their very nature, are short-term modifications in
such practices.
6. If the contamination of a particular crop or dietary component is so high
that it would not be acceptable for local use, the crop or dietary component is
not considered acceptable for use in other areas to which it may be transported.
2.53 Also, in the development of guidance for taking protective
action it is necessary to consider:
1. The possible risk to health associated with the projected dose to the
population from radioactive materials.
[p. 27]
2. The amount by which the projected dose can be reduced by taking certain
actions.
3. The total impact, including risks to health, associated with these actions.
4. The feasibility of taking the actions.
2.54 Decisions to implement protective actions involve a com-
parison of the risk due to radiation exposure with the undesirable
features of the contemplated actions. The critical decisions to be
made are whether to permit unrestricted use of feed crops or food
products, to place restrictions on the normal use of feed crops or
food products, or to destroy feed crops or food products. The
value of a protective action depends on how much the projected
dose per individual can be reduced by the action and the number
of people affected. Protective actions affecting a particular pop-
ulation group will yield a greater return in relation to their dis-
advantages if projected doses are high rather than low. Since
high levels of contamination probably will be limited to small
areas, protective actions are more likely to be required in such
areas rather than over large regions.
2.55 The Council has adopted the term "Protective Action
Guide" (PAG), denned as the projected absorbed dose to in-
dividuals in the general population that warrants protective action
following a contaminating event. The projected dose is the dose
that would be received by individuals in the population group
from the contaminating event if no protective action were taken.
If the projected dose exceeds the PAG, protective action is in-
dicated.
-------
1200 LEGAL COMPILATION—RADIATION
2.56 Protective actions are appropriate when the health benefits
associated with the reduction in exposure to be achieved are suf-
ficient to offset the undesirable features of the protective actions.
The PAG's represent the judgment as to where this balance should
be for the conditions considered most likely to occur. If, in a
particular situation, there is available an effective action with low
total impact, initiation of such action at a projected dose lower
than the PAG may be justifiable. If only high impact action would
be effective, initiation of such action may be justifiable only at a
projected dose higher than the PAG. The types of actions con-
sidered in the development of guidance in this report include:
[p. 28]
1. Altering production, processing, or distribution practices affecting the
movement of radioactive contamination through the food chain and into the
human body. This action may include storage of food supplies and animal
feeds to allow for radioactive decay.
2. Diverting affected products to uses other than human consumption.
3. Condemning affected products.
2.57 An alteration of the normal diet of an individual is gen-
erally less desirable than the measures listed and should not be
undertaken except on the personal advice of a physician.
2.58 In the situations where there are slowly increasing levels
of widespread contamination over a period of months or years
throughout the nation's food producing areas, protective actions
presently contemplated for acute, local contamination situations
would not be effective. The consideration of long duration pro-
tective actions to reduce the average intake of radioactive mate-
rials for large populations involves many complex interacting fac-
tors of available, or potentially available, resources. In addition,
a decision to require changes in agricultural and food processing
practices or dietary habits could be implemented only through
policy decisions involving land utilization, work force distribution,
and the allocation of technical talent to the long-term control effort.
[p. 29]
SECTION III
THE ACUTE LOCALIZED CONTAMINATING EVENT
3.1 Situations justifying protective actions could occur from
such events as an industrial accident, possibly involving a nuclear
reactor or a nuclear fuel processing plant, and release of radio-
-------
GUIDELINES AND REPORTS 1201
active materials from nuclear explosions. The considerations in-
volved in determining appropriate criteria for protective action
following an acute contaminating event have led to the develop-
ment of three categories of dietary pathways. Categories I and II
relate to intake in the first year following acute deposition, while
Category III considers intake after the first year.
3.2 Category I is concerned with the immediate transmission of
the radionuclides through the pasture-cow-milk-man pathway.
The three nuclides of interest may be transmitted through this
pathway simultaneously when they are deposited simultaneously
on pasture. Experimental data indicate that nearly all the radio-
active materials appearing in milk through this pathway will have
occurred within 100 days, and protective actions may have to be -
applied for this length of time. Protective action must be initiated
within about a week to be effective in averting most of the potential
exposure. This category of transmission may be the only one of
importance for strontium-89 because of its relatively short radio-
active half life (50.5 days).
3.3 Category II is concerned with the transmission of radio-
nuclides to man through dietary pathways other than that spe-
cified as Category I during the first year following an acute
contaminating event. This involves the use of feed crops for an-
imals, including dairy cattle, and plant products used directly for
human consumption. The radioactive materials initially deposited
on such crops in the field do not gain access to the human food
chain until after the crops are harvested. Immediate action to
reduce the potential intake will not usually be required because of
the normal delay in the use of such crops. However, an early de-
cision will be required as to the need for examination of the radio-
nuclide content of harvested crops before they enter normal
marketing channels. Strontium-90 and cesium-137 may be trans-
mitted through the cow's feed to milk; cesium-137, in particular,
may be transmitted through feed to meat; both may be transmitted
to man through the direct consumption of plant products.
[p. 30]
3.4 Category III is primarily concerned with the long-term
transmission of strontium-90 through soil into plants in the years
following a contaminating event. Residual contamination of
cesium-137 on pasture when there is a heavy root mat may be a
consideration for one to two years following a sufficiently severe
contaminating event. Because of the long lead time available to
assess the possible radionuclide intakes, immediate action is not
necessary. Any action that may be taken must be based on the
-------
1202 LEGAL COMPILATION—RADIATION
long-term reduction of the radionuclide concentrations in products
grown in the area.
8.5 In considering the desirability of initiating protective ac-
tions following a contaminating event, it is necessary to consider
the three categories separately. The benefits of a protective ac-
tion taken in one category are largely independent of whether
action is taken in another. Individuals may be exposed to radio-
activity from all three categories; however, the guides for in-
dividual categories recommended in this report are sufficiently
conservative (i.e., low) that it is unnecessary to provide an ad-
ditional limitation on combined doses. Actions that are likely to
be taken in Categories I and II would be effective against any
of the three nuclides. Since all nuclides contribute to bone mar-
row dose, the sum of the projected doses to the bone marrow
should be compared to the numerical value of the respective guide
in the appropriate category when the need for protective action is
considered.
Guidance Applicable to Category I
3.6 Conditions in Category I develop rapidly from the onset of
radionuclide deposition, and protective actions must be initiated
within about a week to avert most of the intake. The protective
actions considered effective are:
1. The change of cattle from pasture to stored feed.
2. The substitution of unaffected fresh milk for affected fresh milk by
alteration of processing or distributing practices, with subsequent diversion
(depending on the radionuclides) or disposal of contaminated milk.
Since these actions are effective for all radionuclides of concern,
actions taken for one contaminant will simultaneously reduce the
intake of others. Protective actions to avert exposure may be ap-
propriate for a shorter or longer time than 100 days, depending on
[P. 31]
the circumstances.
3.7 The concept of the Protective Action Guide, as presented in
Report No. 5, was developed for use as guidance in situations in-
volving the rapid transmission of radionuclides from pasture to
milk to man with the inherent limitations on the types of ef-
fective actions for which the necessary resources would be gen-
erally available. Such a situation has many of the characteristics
of an emergency requiring an immediate decision as to the need
for protective actions. The possible need for early actions to avoid
most of the projected intake that may result from an acute lo-
calized contaminating event involving strontium-89, strontium-90,
and cesium-137 is also present in Category I.
-------
GUIDELINES AND REPORTS 1203
3.8 In the application of the PAG's the following guidance is
provided:
1. If the projected dose exceeds the PAG, protective action is indicated.
2. The amount of effort that properly may be given to protective action will
increase as the projected dose increases.
3. The objective of any action is to achieve a substantial reduction of the
dose that would otherwise occur—not to limit it to some prespecified value.
4. The value of the proposed protective actions must be weighed against
their total impact. Each situation should be evaluated individually. As the
projected doses become less the value of protective actions becomes correspond-
ingly less.
3.9 The guidance applicable to strontium-89, strontium-90, and
cesium-137 is given in terms of the projected dose to the whole
body or bone marrow. Because of the risk associated with irradia-
tion of bone marrow or the whole body as compared to irradiation
of the thyroid, and the comparability of the protective actions
available to avert the exposure, it is considered appropriate that
the PAG's applicable to these radionuclides be lower than the PAG
recommended for iodine-131. In view of these considerations it
is recommended that:
1. The PAG for the transmission of strontium-89, strontium-90, and
cesium-137 through milk under the conditions of Category I be a mean dose
[p. 32]
of 10 rads in the first year to the bone marrow or whole body of individuals
in the general population; and provided further, that the total dose resulting
from Category I not exceed 15 rads. For purposes of applying this guide the
total dose from strontium-89 and cesium-137 is assumed to be the same as
the dose in the first year, whereas the total dose from strontium-90 is assumed
to be five times the dose from strontium-90 in the first year. As an operational
technique it is assumed that the guide will be met effectively if the average
projected dose to a suitable sample of the population (children approximately
1 year of age) does not exceed one-third of the numerical value prescribed
for the individual.
3.10 For the radionuclides of interest, the total intake by man
in Category I following a contaminating event is estimated from
the assumptions that: (1) Equation (1) describes the radio-
nuclide concentrations in milk as a function of time; (2) the
average calcium content of milk is 1 gram per liter; (3) the daily
intake of milk is 1 liter; and (4) the total intake will occur within
100 days. Tables 4, 5 and 6 are based on these assumptions and
the relationships between total intake and projected dose, given in
paragraphs 2.46 and 2.50.
-------
1204 LEGAL COMPILATION—RADIATION
TABLE 4—RELATION BETWEEN STRONTIUM-89 INTAKE THROUGH MILK
AND THE AVERAGE DOSE TO BONE MARROW1
Maximum
concentration in
milk (nCis'Sr/1)
63
370
740
1110
1870
3700
18700
Total intake UCi »'Sr)
1.7
10
20
30
50
100
500
Average dose to
bone marrow (rads)
0.17
1.0
2.0
3.0
5.0
10
50
1 Based on a dose of 0.1 rad to bone marrow following an intake of 1 microcurie associated with 100
grams of calcium.
pCi=microcurie=l X 10-6 curie.
[p. 33]
TABLE 5—RELATION BETWEEN STRONTIUM-90 INTAKE THROUGH MILK
AND THE AVERAGE DOSE TO BONE MARROW1
Maximum
concentration in
milkMnCi«Sr/l)
8
51
100
155
250
510
Total intake
GaCi »Sr)
0.28
1.67
3.34
5.0
8.3
16.7
Average dose
to bone marrow
in first year
(rads)
0.17
1.0
2.0
3.0
5.0
10
Total dose to
bone marrow
(rads)
0.85
5.0
10.0
15.0
25.0
50
1 Based on a dose of 0.6 rad in the first year and a total (70-year) dose of 3 rads to bone marrow follow-
ing an intake of one microcurie associated with 100 grams of calcium.
2 Numbers below 100 have been rounded to the nearest unit; numbers above 100 to the nearest 5 units.
/iCi=microcurie=l X 10~4 curie.
TABLE 6—RELATION BETWEEN CESIUM-137 INTAKE THROUGH MILK AND THE DOSE TO WHOLE BODY'
Maximum
concentration in
milk(nCi «7Cs/l)
41
240
480
720
1190
2400
Total intake G*Ci 13'Cs)
1.3
7.7
15.4
23
38
77
Dose to whole body
(rads)
0.17
1.0
2.0
3.0
5.0
10
1 Based on a dose of 0.13 rad following an intake of one microcurie.
/iCi=microcurie=l x 10-*curie.
[p. 34]
Guidance Applicable to Category II
3.11 Conditions in Category II that may warrant action develop
more slowly, in comparison to those of Category I, and generally
-------
GUIDELINES AND REPORTS 1205
permit more time for application of protective actions after the
deposition of radioactive material has occurred. The time of depo-
sition of radioactivity relative to the various stages in the plant
growth cycle will be a major factor affecting the concentration of
radionuclides in food and feed. Although the variations can be
large, depending on the time of year and the particular produce
grown in the contaminated area, the concentrations of radionu-
clides reaching man through Category II pathways will be less, in
most cases, than those in Category I. The need for initiating a
program to assess the degree of contamination and the use of
crops in Category II can generally be deduced from the situation
found in Category I. Protective actions usually will not be re-
quired in Category II if they were not required in Category I.
3.12 The significance of radioactive contamination should be
evaluated in terms of potential daily and total intakes by persons
who are assumed to derive major portions of their diets from the
use of locally grown crops. A wide range of situations may exist
within Category II. It is generally impossible to predict total
radiation doses solely from the degree of contamination of a par-
ticular crop. The complexity of such situations and the fact that
for most crops immediate action, beyond assuring that the ques-
tionable crops are not marketed before appropriate assessment
can be made, make it impractical to provide numerical guides ap-
plicable to individual products. However, if it appears that the
total projected dose to a suitable sample of a population group
from the use of all crops in Category II is larger than the PAG
recommended for this category, protective actions should be
initiated against those crops that would make major contributions
to that dose. In order to meet the objective of Item 6, paragraph
2.52, this suitable sample would be from a group considered to
live in a contaminated area and also be considered to make max-
imum utilization of locally produced food products.
3.13 Depending on the circumstances, the protective actions
considered appropriate for Category II are:
1. Modification of animal feed utilization practices or of food processing and
marketing practices.
2. Diversion of one or more crops so that the radionuclides of interest are
[p. 35]
removed from access to the human food chain.
3. Destruction of one or more food crops or animal feed crops.
The effectiveness of the actions in eliminating potential intake
from the use of the crops increases in the order listed. The kinds
of protective action applicable to the use of animal feed crops and
food crops directly contaminated by deposition and their relative
-------
1206 LEGAL COMPILATION—KADIATION
feasibility can be expected to vary quite widely from one situation
to another. Destruction of food crops should seldom be required.
The selection of individual foodstuffs for disposal or for diversion
to non-human use will depend on many factors, including: (1) the
fractional contribution of radioactive material that each dietary
item makes to the total diet, assuming a normal diet; (2) the
reduction in projected dose that could result from the elimination
of each dietary item; and (3) the possible access to the food chain
through diversion to alternate non-human uses.
3.14 In view of these considerations it is recommended that:
2. The Protective Action Guide for the transmission of strontium-89, stron-
tium-90, and cesium-137 through food crops or animal feed crops under the
conditions in Category II be a dose of 5 rads in the first year to the bone marrow
or whole body of individuals in the general population. As an operational
technique it is assumed that the guide will be met effectively if the average
projected dose to a suitable sample of the local population is no larger than
2 rads in the first year to the whole body or bone marrow.
3.15 The intent of the recommendation is to discourage delib-
erate introduction of contaminated foods into supplies of uncon-
taminated foods as an acceptable means of solving a problem
involving radioactive contamination of the environment. It is
recognized that all crops that might be affected by a contaminating
event will not be harvested at the same time. In addition, some
crops might not normally be used until more than a year after the
event. The PAG for this category is intended to apply to the
evaluation of the projected dose from the use of crops that were
contaminated at the time of the event and are harvested within a
year.
[p. 36]
3.16 The transmission of strontium-89, particularly to children
approximately 1 year of age, through dietary products other than
milk should generally be insignificant in comparison to its trans-
mission through milk. Under certain conditions it is conceivable
that significant quantities of strontium-89 could be transmitted to
milk if contaminated crops are used to feed dairy cattle before
the strontium-89 has been lost by radioactive decay. Once the crop
has been harvested, strontium-89 is lost only by the process of
radioactive decay during storage, and the relationship between the
concentration of strontium-89 in milk and the total intake differs
from that in Category I. The maximum projected intake in this
case is 74 (1.44 X radioactive half-life) times the measured con-
centration per liter of milk assuming a consumption of 1 liter of
milk per day.
3.17 The strontium-90 and cesium-137 content of animal feed
-------
GUIDELINES AND REPORTS 1207
depends on the concentration at the time the crop is harvested.
There is no significant loss of these radionuclides by radioactive
decay in time periods of 1 to 2 years. If the feed is used for dairy
cows the strontium-90 and cesium-137 concentration in milk would
reach a steady state value related to the cow's daily intake. The
concentration in milk would remain at that value as long as the
feed is used. Therefore, the relation between the concentration of
strontium-90 and cesium-137 in milk and the total quantity se-
creted into the milk would vary, depending on how long the par-
ticular feed crop is used. However, this quantity can be estimated
in advance if the concentrations in the feed are known and the use
of the feed has been determined.
3.18 In addition to the transmission of strontium-90 and ces-
ium-137 to milk through the use of contaminated crops for feeding
dairy cattle, the possible contribution resulting from the use of
other crops such as fruits, vegetables, or cereal grains growing in
the same area must also be considered. In these cases, it is ex-
pected that the largest part of the contamination will be associated
with one or two particular crops and the action should be directed
at eliminating this part of the potential exposure.
3.19 The relationship between the total intake of strontium-89
and strontium-90 and the projected doses as shown in columns 2
and 3 of Tables 4 and 5 is valid if the particular intake is to be
evaluated over a period of 1 to 3 months. The relationship be-
tween the total intake of cesium-137 and dose shown in columns
2 and 3 of Table 6 may be used in estimating the projected dose
from cesium-137
[p. 37]
Guidance Applicable to Category HI
3.20 In this category there can be extremely wide variations in
the situations that might exist in relation to (1) areas involved,
(2) crops affected, (3) possible rate of the decrease in strontium-
90 gaining access to plants, and (4) possible actions. In addition,
one is now concerned with problems of long-term chronic exposure.
Actions that may be effective in Category III involve major long-
term changes in farming practices such as selection of crops,
chemical or mechanical treatment of soil, land utilization, or all
three of these. Following a sufficiently severe event, long-term
restrictions may be placed on the use of farmland for food or feed
production. The range of considerations that may enter into a de-
cision to take action in this category together with the length of
time available for detailed evaluations make it less meaningful to
provide a numerical PAG than to provide guidance for evaluation
-------
1208 LEGAL COMPILATION—RADIATION
of long-term situations. The nature of the situation is such that
detailed evaluation would not be required except in situations in
which levels of environmental contamination are greater than
those that might occur under guidance provided for normal peace-
time operations.
3.21 In view of these considerations it is recommended that:
3. The desirability of protective action against exposure to environmental
radioactivity from situations in Category III be determined on a case-by-case
basis. If it appears that annual doses to the bone marrow after the first year
may exceed 0.5 rad to individuals or 0.2 rad to a suitable sample of the popula-
tion, such situations shall be appropriately evaluated.
3.22 Strontium-89 will have essentially disappeared through
radioactive decay within 12 to 18 months after the initial deposi-
tion. This radionuclide, therefore, is not a consideration in the
utilization of land in the years following a high deposition.
3.23 Long-term exposure from strontium-90 entering the food
chain through root mats on pastures or through the soil into plants
may be an important factor in land utilization for several years
following a sufficiently high deposition of strontium-90 in the en-
vironment. Land used for pastures, animal feed crops, or other
[p. 38]
crops such as fruits and vegetables may be affected in varying
degrees.
3.24 Cesium-137, particularly on pastures with a heavy root
mat, may be an important factor in land utilization for 1 to 2 years
after an acute contaminating event. Direct transmission to
plants from cesium-137 in the soil is generally not expected to be
limiting since cesium-137 is tenaciously bound by soil particles.
[p. 39]
SECTION IV
WORLDWIDE CONTAMINATION
FROM STRATOSPHERIC FALLOUT
4.1 Stratospheric fallout from past atmospheric testing of nu-
clear weapons has led to a worldwide deposition of fission products
in the environment. It has led to a generally fluctuating but grad-
ually increasing level of long lived radionuclides in food products.
These levels reached their peak in 1964. All food supplies may be
-------
GUIDELINES AND REPORTS 1209
affected simultaneously to a greater or lesser degree but the aver-
age radionuclide levels in the food produced in a large area, such
as a state, are more significant than local fluctuations within the
area. The general situation has been studied by the FRC from
the standpoint of worldwide fallout from past atmospheric testing
(FRC Report Nos. 3, 4, and 6).
4.2 It appears that the intra-regional variations of food con-
tamination are relatively small. In 1963 the highest annual av-
erage strontium-90 content of milk from stations among "wet"
areas was less than three times the annual average of all stations
in these areas. The highest monthly average for this station was
about twice its annual average and its highest weekly sample was
about three times its annual average. In the United States the
annual average of the station with the highest average was about
20 times that of the station with the lowest average. Regional
variations in cesium-137 and strontium-89 concentrations were
comparable. (FRC Report No. 6)
4.3 The relationship between the amount of fallout deposited
per unit area and the resultant dietary intake by man is not con-
stant, but is influenced by a variety of factors. These include
those factors influencing the subsequent movement of radionu-
clides through the environment to the diet and the dietary habits
of specific population groups or individuals.
4.4 The studies of fallout in the United States from past testing
(FRC Report Nos. 4 and 6) have indicated that:
1. From tests conducted in 1962, strontium-89 gave an estimated average
dose of 0.04 rad to bone and 0.01 rad to bone marrow. These doses were divided
about equally between 1962 and 1963, giving an annual dose in each year equal
to about 3 to 4 percent of the numerical values of the RPG's for bone and bone
marrow. In 1964 the estimated dose from strontium-89 was negligible.
[p. 40]
2. The average annual strontium-90 content of the total diet in the "wet"
areas of the United States from all past testing reached a peak value of ap-
proximately 40 picocuries of strontium-90 per gram calcium in 1964. During
the period this concentration is maintained, it would lead to annual doses of
about 0.03 rad in new bone and about 0.01 rad in bone marrow. These values
are about 6 percent of the numerical values of the RPG's for bone and bone
marrow.
3. Internal exposure from cesium-137 to be taken in through the diet in
the conterminous United States during1 the next 30 years has been estimated
to be about 0.01 rad. This is about 0.2 percent of the RPG for the gonads (5
rems in 30 years averaged over the population).
4.5 The RPG's were developed for controlling normal peace-
time operations assuming a condition of continuous intake and
chronic exposure affecting large numbers of people for time-spans
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1210 LEGAL COMPILATION—RADIATION
of generations. The numerical values of the RPG's do not and
cannot establish a line which is safe on one side and unsafe on the
other. Nevertheless, annual radiation doses from fallout equal to
or greater than the numerical values of the RPG's can be used as
an indication of when there is a need to initiate a careful evalua-
tion of fallout exposures. Caution should be exercised in institut-
ing protective actions in situations where exposures are near the
numerical values of the RPG's, since the biological risks are so
low that the actions could have a net adverse rather than ben-
eficial effect on the public well-being.
4.6 The practicality and value of protective actions against
widespread environmental contamination from stratospheric fall-
out is limited because:
1. The condition to be alleviated is chronic exposure from long-term con-
tinuous intake (10 years or more).
2. A reduction in potential intake under these conditions requires basic
changes in long-term agricultural practices, food processing practices, dietary
habit, or all three.
3. The actions would have to be applied on a broad enough scale to reduce
the average quantity of radionuclides in the total diet from foods produced
throughout large areas or the entire country.
[p. 41]
Cesium-137 and Strontium-90 in Arctic Alaska
4.7 Although the amount of fallout deposited per unit area in
the Arctic is about one-fifth that deposited in 30°-40° latitude
band, a combination of ecological conditions and specific dietary
habits of the Eskimos and Indians result in higher strontium and
cesium body burdens than are found in the conterminous United
States. The lichen-caribou (reindeer)-man pathway is the most
important food chain contributing to these body burdens.
4.8 Lichens accumulate nutrients and certain other materials
which are deposited directly on them from the air. Their growth
is slow and they tenaciously retain the fallout materials to which
they are exposed. The concentrations of cesium-137 and stron-
tium-90 in lichens are among the highest in plant life measured
anywhere in the world. These radionuclides also tend to ac-
cumulate in other persistent vegetation, such as sphagnum moss
and the crowns of sedge.
4.9 Lichens are important in the diet of caribou and reindeer,
particularly during the winter. Other plants such as sedges are
also consumed by these animals. This diet leads to relatively high
concentrations of cesium-137 and strontium-90 in the meat of these
animals. High levels in the food chain can be expected to persist
for several years in the arctic region. The individuals and small
-------
GUIDELINES AND REPORTS 1211
population groups with the highest body burdens of cesium-137 are
those whose dietary preference is caribou meat. Average body
burdens of cesium-137 in these inhabitants were about three times
as high in 1964 as they were in 1962. People with more diversified
diets have lower body burdens. In 1964 the annual dose to the
Eskimos having the highest body burdens was slightly more than
one-half the RPG of 3,000 nanocuries for whole body exposure of
individuals in large population groups. Average doses for adults
of the same village are less than one-third the RPG. Although the
Federal Radiation Council did not set a specific RPG for cesium-
137, in either Report No. 1 or No. 2, it did state in the Memoran-
dum for the President (Federal Register, September 26, 1961):
"The characteristics of cesium-137 lead to direct comparisons with
whole body exposure for which recommendations by the Council
have already been made." This implies that the RPG would be
0.5 rem * in a year to the whole body of individuals in the general
population when the doses can be measured directly, or an average
of 0.17 rem to a suitable sample of the population group, when di-
rect measurement is not practicable. Therefore, an annual average
[p. 42]
body burden in adults of 3,000 nanocuries and 1,000 nanocuries
would be estimated to result in these respective doses. The body
burdens of cesium-137 in the groups of interest are being mea-
sured directly. If a comparison with the guidance provided by
the FRC is to be made, the applicable RPG is 0.5 rad per year and
the corresponding annual average body burden is 3,000 nanocuries
of cesium-137 in adults. Strontium-90 burdens in bone appear to
be about four times as high as those found in the conterminous
United States.
Conclusions
4.10 Reduction in transmission of radionuclides to man under
worldwide fallout conditions could only be achieved by long-term
changes in (1) agricultural practices, (2) food processing prac-
tices, or (3) basic dietary habits. Consideration of such basic
economic and social changes is not warranted when annual doses
from environmental contamination are comparable to the numer-
ical value of the annual dose recommended for the RPG. It has
not been possible to visualize circumstances in which the bal-
ancing of the risk of radiation against the undesirable conse-
quences of the protective measures on social, economic, and
*For the purposes of this report the units "rem" and "rad" are considered numerically equal.
-------
1212 LEGAL COMPILATION—RADIATION
political institutions can be reduced in advance to numerical guides
for mandatory action under these circumstances.
4.11 On the basis of this information on stratospheric fallout
the Council concluded that the health risk from radioactivity in
food over the next several years would be too small to justify pro-
tective actions to limit the intake of radionuclides either by diet
modifications or by altering the normal distribution and use of
food, particularly milk and dairy products.
4.12 In view of these considerations it is recommended that:
5. Surveillance of the radionuclide content in food products contaminated
with worldwide fallout be continued at levels appropriate to the situation.
6. Surveillance and research programs examining the special ecological sit-
uations in the arctic region continue until future trends can be predicted with
greater confidence.
[P. 43]
7. Nationwide programs to reduce potential exposure of the population
from gradually increasing levels of environmental contamination, such as that
associated with worldwide fallout, are not necessary now nor for future levels
of fallout from past testing.
[p. 44]
4.1g(l) RADIATION PROTECTION GUIDANCE FOR FEDERAL
AGENCIES (MEMORANDUM TO THE PRESIDENT),
FEDERAL RADIATION COUNCIL
May 22,1965,30 Fed. Reg. 6953 (1965)
FEDERAL RADIATION COUNCIL
RADIATION PROTECTION GUIDANCE FOR FEDERAL AGENCIES
MEMORANDUM FOR THE PRESIDENT
MAY 17,1965.
Pursuant to Executive Order 10831 and Public Law 86-373, the
Federal Radiation Council is transmitting recommendations for the
approval of the President for guidance of Federal agencies in their
radiation protection activities. The present recommendations are
directed to guidance for protective actions affecting the normal
production, processing, distribution, and use of food products for
human consumption when such products are contaminated with
strontium-89, strontium-90, or cesium-137. It is the intention of
the Council to release the background material leading to these
recommendations as Staff Report No. 7 when the recommendations
are approved.
-------
GUIDELINES AND REPORTS 1213
Background. The first two memorandums that provided guid-
ance for Federal agencies in the conduct of their radiation pro-
tection activities were approved by the President on May 13, 1960,
and September 20, 1961. These provided a general philosophy of
radiation protection and the general principles of control based on
the annual intake of radionuclides. The recommendations also
provided the basis for the control and regulation of normal peace-
time operations in which exposure to radiation is a factor. The
Radiation Protection Guides (RPG's) were designed to limit the
exposures of the whole body and of certain organs of radiation
workers and the general population resulting from the use of
ionizing radiation in normal peacetime operations.
During the atmospheric testing of nuclear weapons in 1961 and
1962 the question arose as to the use of those RPG's for determin-
ing the conditions under which the production, processing, distri-
bution, and use of food, particularly fresh fluid milk, should be
altered to reduce human intake of radionuclides from fallout. In
September 1962 the Federal Radiation Council stated its position
on this subject, and in 1963 the Council reiterated that those exist-
ing guides were not applicable to a determination of a need for
protective actions and noted that it would recommend guidance on
the subject to the President.
Specific guidance for protective actions applicable to contamina-
tion of food by iodine-131 was approved by the President in July
1964.
Data on worldwide fallout from past testing of nuclear weapons
in the atmosphere have been reviewed by the Federal Radiation
Council and the findings reported in FRC Report Nos. 3, 4,
and 6.
Fundamental differences between Radiation Protection Guides
and Protective Action Guides. FRC Report Nos. 1 and 2 provide
radiation protection guidance for the control and regulation of the
normal peacetime uses of nuclear technology in which control is
exercised primarily on the design and use of the radiation source.
The RPG's in those reports were developed as guidelines for the
protection of radiation workers and the general public against ex-
posures that might result from routine uses of ionizing radiation.
In formulating these guides there was a judgment, or balance,
between the possible risks associated with a particular radiation
exposure and the reasons for allowing the exposure.
An important factor in providing guides for any purpose is the
change in risk assigned to higher or lower doses and the corres-
ponding effort to reduce them. Other factors influencing informed
opinion of where and why a particular balance should be made in-
-------
1214 LEGAL COMPILATION—RADIATION
elude views regarding prevailing practices and the relative im-
portance of health risks in relation to economic, political, or other
considerations of national welfare.
Although radiation doses numerically equal to the RPG's may
impose a risk so small that they can be accepted each year for a
lifetime if there is significant benefit from the programs causing
the exposure, they do not and cannot establish a line that is safe
on one side and unsafe on the other. Rather, some risk of injury
may exist at any level of dose and the risk continuously increases
with dose. Caution should be exercised in decisions to take pro-
tective actions in situations where projected doses are near the
numerical values of the RPG's since the biological risks are so low
that the actions could have a net adverse rather than beneficial ef-
fect on the public well-being.
In contrast to the guidance for control at the point of release,
FRC Report No. 5 provided general guidance for the protection of
the population against exposure resulting from the accidental re-
lease, or to the unforeseen appearance, of radioactive materials in
the environment. Specific guidance, including a numerical value
for the Protective Action Guide (PAG) was provided for iodine-
131. The PAG represents a consensus as to when, under the con-
ditions considered most likely to occur, intervention is indicated to
avoid radiation exposure that would otherwise result from a tran-
sient environmental contamination condition. This judgment in-
volves health, economic, sociologic, and political factors for which
the relative values are different than for the RPG. These factors
for the PAG may include agricultural policies, the known feasibil-
ity of protective actions, related health impacts, and similar con-
siderations involved in the national interest.
Radionuclides considered. Four radionuclides are particularly
important in considering radioactive contamination of food. These
are iodine-131, strontium-89, strontium-90, and cesium-137.
Iodine-131 was considered in FRC Report No. 5, and this mem-
orandum will deal only with strontium-89, strontium-90 and ce-
sium-137.
Physical and biological factors related to the metabolism of
strontium and cesium have recently been reviewed for the Federal
Radiation Council by a committee selected by the National Acad-
emy of Sciences. Consideration has been given to the irradiation
of the embryo or fetus by these nuclides, as well as irradiation of
infants, children, and adults. Irradiation of bone marrow is con-
sidered to be the most significant from the standpoint of producing
harmful effects. Strontium-89 and strontium-90 deposit selec-
tively in the skeleton causing irradiation of bone marrow adjacent
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GUIDELINES AND REPORTS 1215
to the sites of deposition in the skeleton. Cesium-137 is distributed
through soft tissues and irradiates the whole body, including bone
and bone marrow.
Protective Actions Guides. As stated in Report No. 5, a pro-
tective action is an action or measure taken to avoid most of the
exposure to radiation that would occur from future ingestion of
the foods contaminated with radioactive materials.
Decisions to implement protective actions involve a comparison
of the risk due to radiation exposure with the undesirable features
of the contemplated actions. The critical decisions to be made are
whether to permit unrestricted use of feed crops or food products,
to place restrictions on the normal use of feed crops or food prod-
ucts, or to destroy feed crops or food products.
The Council has adopted the term Protective Action Guide, de-
fined as the projected absorbed dose to individuals in the general
population that warrants protective action following a contami-
nating event. The projected dose is the dose that would be received
by individuals in the population group from the contaminating
event if no protective action were taken. If the projected dose
exceeds the PAG, protective action is indicated. Making use of the
operational technique adopted in the Memorandum for the Pres-
ident, May 1960, protective action would be indicated at an aver-
age projected dose to a suitable sample of the exposed population
equal to one-third of the PAG.
Protective actions are appropriate when the health benefits as-
sociated with the reduction in exposure to be achieved are sufficient
to offset the undesirable features of the protective actions. The
PAG represents the Council's judgment as to where this balance
should be for the conditions considered most likely to occur. If, in
a particular situation, there is available an effective action with
low total impact, initiation of such action at a projected dose lower
than the PAG may be justifiable. If only high impact action would
be effective, initiation of such action may be justifiable only at a
projected dose higher than the PAG. The types of actions consid-
ered in the development of guidance in the memorandum include:
1. Altering production, processing, or distribution practices affecting the
movement of radioactive -contamination through the food chain and into the
human body. This action may include storage of food supplies and animal
feeds to allow for radioactive decay.
2. Diverting affected products to uses other than human consumption.
3. Condemning affected products.
An alteration of the normal diet of an individual is generally less desirable
than the measures listed and should not be undertaken except on the personal
advice of a physician.
-------
1216 LEGAL COMPILATION—RADIATION
Two limiting conditions of environmental contamination have
been examined; an acute localized contaminating event in which
prompt action may be necessary to avoid the exposure that would
otherwise result; and a widespread, generally increasing, low-level
contamination (from stratospheric fallout) that would cause a con-
tinuous intake of radionuclides by large numbers of people for
several years.
The acute localized contaminating event. Situations justifying
protective actions could occur from such events as an industrial ac-
cident, possibly involving a nuclear reactor or a nuclear fuel proc-
essing plant, and release of radioactive materials from nuclear
explosions. The considerations involved in determining appro-
priate criteria for protective action have led to the development of
three categories of dietary pathways which may require decisions
following an acute contaminating event. Categories I and II re-
lated to intake in the first year following acute deposition, while
Category III considers subsequent intake after the first year.
Category I is concerned with the immediate transmission of the
radionuclides through the pasture-cow-milkman pathway. The
three nuclides of interest may be transmitted through this pathway
simultaneously if they are deposited simultaneously on pasture.
Experimental data indicate that nearly all the radioactivity ap-
pearing in milk through this pathway will have occurred within
100 days, and protective actions may have to be applied for this
length of time. Protective action must be initiated within about a
week to be effective in averting most of the potential exposure.
This category of transmission may be the only one of importance
for strontium-89 because of its relatively short radioactive half
life (50.5 days).
Category II is concerned with the transmission of radionuclides
to man through dietary pathways other than that specified as
Category I during the first year following an acute contaminating
event. This involves the use of feed crops for animals, including
dairy cattle, and plant products used directly for human consump-
tion. The radioactivity initially deposited on such crops in the
field does not gain access to the human food chain until after the
crops are harvested. Immediate action to reduce the potential in-
take will not usually be required because of the normal delay in
the use of such crops. However, an early decision will be required
as to the need for examination of the radionuclide content of har-
vested crops before they enter normal marketing channels. Stron-
tium-90 and cesium-137 may be transmitted through the cow's
feed to milk; cesium-137, in particular, may be transmitted
through feed to meat; both may be transmitted to man through the
-------
GUIDELINES AND REPORTS 1217
direct consumption of plant products.
Category III is primarily concerned with the long-term trans-
mission of strontium-90 through soil into plants in the years fol-
lowing a contaminating event. Residual contamination of
cesium-137 on pasture when there is a heavy root mat may be a
consideration for 1 to 2 years following a sufficiently severe con-
taminating event. Because of the long leadtime available to as-
sess the possible radionuclide intakes, immediate action is not
necessary. Any action that may be taken must be based on the
long-term reduction of the radionuclide concentrations in products
grown in the area.
In considering the desirability of initiating protective actions
following a contaminating event, it is necessary to consider the
three categories separately. The benefits of a protective action
taken in one category are largely independent of whether or not
action is taken in another. Individuals may be exposed to radio-
activity from all three categories; however, the guides for indi-
vidual categories recommended in this memorandum are
sufficiently conservative that it is unnecessary to provide an ad-
ditional limitation on combined doses. Since actions that are
likely to be taken in Categories I and II would be effective against
any of the three nuclides in either category, the sum of the pro-
jected doses to the bone marrow should be compared to the numer-
ical value of the respective guide in the appropriate category when
the need for protective action is considered.
Considerations in the development of Protective Actions. The
basic considerations in the development of guidance for the acute
event are:
1. The occurrence of an acute contaminating event which will require pro-
tective action is considered to be so infrequent that it is unlikely that the same
individual will be exposed to more than one event.
2. Exposure to the public from radionuclides in the environment is directly
related to concentration of the radionuclides in food supplies and the length
of time (weeks, months, or years) over which unusual exposures would be ex-
pected to occur. The need for protective actions is generally independent of the
source of contamination.
3. The substitution of food or feeds of lower radionuclide content for con-
taminated products is both effective and practicable.
4. The potential intake of radionuclides by individuals in the general public
from radionuclides in the environment can be reduced whenever modifications
in the normal production, processing, distribution, or dietary practices are con-
sidered to be less objectionable than the radiation risk that would otherwise
have to be accepted.
5. Protective actions, by their very nature, are short-term modifications in
such practices.
6. If the contamination of a particular crop or dietary component is so high
-------
1218 LEGAL COMPILATION—RADIATION
that it would not be acceptable for local use, the crop or dietary component is
not considered acceptable for use in other areas to which it may be transported.
SPECIFIC GUIDANCE
Category I. The concept of the PAG, as presented in Report No.
5, was developed for use as guidance in situations involving the
rapid transmission of radionuclides from pasture to milk to man
with inherent limitations on the types of effective actions for which
the necessary resources would be generally available. Such a sit-
uation has many of the characteristics of an emergency requiring
an immediate decision as to the need for protective actions. The
possible need for early actions to avoid most of the projected intake
that may result from an acute localized contaminating event in-
volving strontium-89, strontium-90, and cesium-137 is also pres-
ent in Category I.
Recommendation. In view of these considerations it is rec-
ommended that:
1. The Protective Action Guide for the transmission of strontium-89, stron-
tium-90, and cesium-137 through milk under the conditions of Category I be a
mean dose of 10 rads in the first year to the bone marrow or whole body of in-
dividuals in the general population; and provided further that the total dose re-
sulting from Category I not exceed 15 rads. For purposes of applying this
guide, the total dose from strontium-89 and cesium-137 is assumed to be the
same as the dose in the first year, whereas the total dose from strontium-90
is assumed to be five times the dose from strontium-90 in the first year. As
an operational technique it is assumed that the guide will be met effectively
if the average projected dose to a suitable sample of the population (children
approximately 1 year of age) does not exceed one-third of the numerical
values prescribed for the individual.
Category II. The time of deposition of radioactive materials
relative to the various stages in the plant growth cycle will be a
major factor affecting the concentration of radionuclides in food
and feed. Although the variations in these concentrations can be
large, depending on the time of year and the particular produce
grown in the contaminated area, the concentrations of radio-
nuclides reaching man through Category II pathways will be less,
in most cases, than those in Category I. The need for initiating a
program to assess the radionuclide content and the use of crops in
Category II can be deduced from the situation found in Category I.
Protective actions usually will not be required in Category II if
they were not required in Category I.
When a need for quantitative examination of crops has been
established the significance of radioactive contamination should be
evaluated in terms of potential daily intake by persons deriving
major portions of their diets from local foods. Within Category II
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GUIDELINES AND REPORTS 1219
a wide range of situations may exist. It is generally impossible to
predict total radiation doses solely from the degree of contamina-
tion of a particular crop. The composition of population groups
consuming food crops in Category II usually will differ from the
composition of groups affected by Category I. The complexity of
such situations and the fact that for most crops, immediate action
beyond assuring that questionable crops are not marketed before
appropriate assessment can be made, make it impractical to pro-
vide numerical guides applicable to individual products. However,
if it appears that the total projected dose to a suitable sample of a
population group from all crops in Category II would be larger
than the PAG recommended for this category, protective actions
should be initiated against those crops that would make major con-
tributions to that dose. In order to meet the objective of item No.
6 of the basic considerations in the development of this guidance,
the suitable sample would be from a group considered to live in a
contaminated area and also be considered to make maximum utili-
zation of locally produced food products.
Recommendation. In view of these considerations it is recom-
mended that:
2. The Protective Action Guide for the transmission of strontium-89, stron-
tium-90, and cesium-137 through food crops or animal feed crops under the con-
ditions in Category II be a mean dose of five rads in the first year to the bone
marrow or whole body of individuals in the general population. As an opera-
tional technique it is assumed that the guide will be met effectively if the aver-
age projected dose to a suitable sample of the local population is no larger than
two rads in the first year to the whole body or bone marrow.
Category III. In this category there can be extremely wide vari-
ations in the situations that might exist in relation to (1) areas
involved, (2) crops affected, (3) possible rate of change in stron-
tium-90 gaining access to plants, and (4) possible actions. In
addition, one is now concerned with problems of long-term chronic
exposure. Actions that may be effective in Category III involve
major long-term changes in farming practices such as selection of
crops, chemical or mechanical treatment of soil, land utilization, or
all three of these. Following a sufficiently severe event, long-term
restrictions may be placed on the use of farmland for food or feed
production. The range of considerations that may enter into a
decision to take action in this category together with the length of
time available for detailed evaluations make it less meaningful to
provide a numerical PAG than to provide guidance for evaluation
of long-term situations. The nature of the situation is such that
detailed evaluation would not be required except in situations in
which levels of environmental contamination are greater than
-------
1220 LEGAL COMPILATION—RADIATION
those that might occur under guidance provided for normal peace-
time operations.
Recommendations. In view of these considerations it is recom-
mended that:
3. The desirability of protective action against exposure to environmental
radioactivity from situations in Category III be determined on a case-by-case
basis. If it appears that annual doses to the bone marrow after the first year
may exceed 0.5 rad to individuals or 0.2 rad to a suitable sample of the popula-
tion such situations shall be appropriately evaluated.
It is recommended that:
4. The guidance contained in the preceding recommendations be approved for
use of Federal agencies in the conduct of those radiation protection activities
affecting the normal production, processing, distribution, and use of food and
agricultural products following acute radioactive contamination of the environ-
ment.
The numerical values of absorbed doses -specified as guides for an acute
contaminating event are not intended to authorize deliberate releases expected
to result in absorbed doses of these magnitudes, nor do they have any relevance
to civil defense applications.
Worldivide contamination from stratospheric fallout. Strat-
ospheric fallout from past atmospheric testing of nuclear weapons
has led to a worldwide deposition of fission products in the environ-
ment. The studies of fallout in the United States from past testing
(FRC Report Nos. 4 and 6) have indicated that:
1. In the conterminous United States strontium-89 gave estimated average
total doses of 0.04 rad to bone and 0.01 rad to bone marrow. These doses were
divided about equally between 1962 and 1963. In 1964 the estimated dose from
strontium-89 was negligible.
2. The average annual strontium-90 content of the total diet in the "wet"
areas of the United States reached a value -of approximately 40 picocuries of
strontium-90 per gram calcium in 1964. This could lead to an average annual
dose in new bone and in bone marrow of about 0.03 and 0.01 rad, respectively.
In Alaska strontium-90 burdens in bone of a few individuals appear to be
about four times as high as those found in the conterminous United States.
3. Internal exposure from cesium-137 to be taken in through the diet in the
conterminous United States during the next 30 years has been estimated to
be about 0.01 rad. In Alaska, although the amount of fallout deposited per
unit area is about one-fifth as much as that deposited in the 30°-40° latitude
band, a combination of ecological conditions and specific dietary habits of some
Eskimos and Indians causes higher cesium body burdens than are found in
the conterminous United States. Average body burdens of cesium-137 in these
inhabitants were about three times as high in 1964 as they were in 1962. The
estimated annual whole body doses to these individuals ranged from about
one-quarter to one-half of the numerical value of the RPG for individuals
in the general population.
On the basis of this information on stratospheric fallout the Council con-
cluded that the health risk from radioactivity in food over the next several
-------
GUIDELINES AND REPORTS 1221
years would be too small to justify protective actions to limit the intake of
radionuclides either by diet modifications or by altering the normal distribu-
tion and use of food, particularly milk and dairy products.
Recommendations. In view of these considerations it is recom-
mended that:
5. Surveillance of the radionuclide content in food products contaminated
with worldwide fallout be continued at levels appropriate to the situation.
It is recommended that:
6. Surveillance and research programs examining the special ecological situa-
tions in the arctic region continue until future trends can be predicted with
greater confidence.
It is recommended that:
7. Nationwide programs to reduce potential exposure of the population from
gradually increasing levels of environmental contamination, such as that
associated with worldwide fallout, are not necessary now nor for future levels
of fallout from past testing.
ANTHONY J. CELEBREZZE,
Chairman.
The recommendations numbered "1" through "7" contained in
the above memorandum are approved for the guidance of Federal
agencies, and the memorandum shall be published in the FEDERAL
REGISTER.
Dated: May 20, 1965.
LYNDON B. JOHNSON.
4.1h GUIDANCE FOR THE CONTROL OF RADIATION
HAZARDS IN URANIUM MINING, REPORT NO. 8,
STAFF REPORT OF THE FEDERAL RADIATION COUNCIL,
SEPTEMBER 1967
CONTENTS
Page
Tables and figures iv
Section
I. Introduction 1
II. The Radiation Environment Associated With Uranium Mining .. 9
III. Biological Effects Associated With Exposure to Radon and
Radon Daughters With Special Reference to Lung Cancer 17
IV. Control Capabilities in Uranium Mines 33
V. Summary and Recommendations 43
-------
1222 LEGAL COMPILATION—RADIATION
Appendix. Dosimetric and Eadiobiological Considerations Related
to the Analysis of Radiation Hazards in
Uranium Mining omitted in this publication
[p. iii]
TABLES AND FIGURES
Page
Table
1. Estimates of the number of mines producing uranium ore during the
calendar year as reported by the industry to the U.S. Bureau of Mines
(1954-64) and AEC (1965-66) 4
2. Number of men employed in uranium mines 4
3. The uranium series 10
4. Estimated distribution of mines by Working Level ranges from 1956
through 1959 12
5. Summary of radon daughter concentrations by Working Level
ranges during the third quarter of 1965 and 1966 13
6. Lung cancer mortality between July 1955 and June 1065 inclusive—
white miners who began underground uranium mining before July
1955 21
Figure
1. Observed and expected annual lung cancer mortality per 10,000
miners and 95 percent confidence limits in relation to exposure .... 22
7. Ventilation cost estimates—11 mine study 36
8. Ventilation cost estimates—3 mine study 36
APPENDIX
Table
1. Energies and ranges of alpha particles in tissue 50
2. Ion density in soft tissue 50
3. Average dose rates to the epithelium of the traches and main bronchi 51
4. Thickness of bronchial epithelium in different parts of the lungs .... 53
5. Approximate annual dose (rads) in reference atmosphere 54
Figure
1. Location of the biological target 55
[p. iv]
-------
GUIDELINES AND REPORTS 1223
SECTION I
INTRODUCTION
1.1 This report supersedes the preliminary FRC staff Report
No. 8 which was released on May 7, 1967, for discussion in the
Joint Committee on Atomic Energy hearings on radiation ex-
posure of uranium miners. It contains background material used
in the development of guidance for Federal agencies in regulatory
programs and in programs of cooperation with States concerning
radiation protection in the mining of uranium ore, and seeks to
provide guidance for long-term radiation protection in uranium
mining. Periodic review will be necessary to incorporate new in-
formation and new surveillance or control techniques as they are
developed. The report also includes recommendations for addi-
tional research and recordkeeping needed to provide a firmer basis
for the evaluation of radiation risks in this industry.
1.2 The use of uranium, as a source of nuclear energy for the
electric power industry, is developing during a period when Gov-
ernment procurement for military purposes is declining. These
two needs are complementary with respect to ore production, and
operate to maintain the uranium mining industry as an activity of
substantial importance to the national economy. The uranium
mining industry is located in 10 Western States, 5 of which pro-
duce over 90 percent of the total domestic uranium ore. The value
of recoverable uranium in ore produced in four of these States as
a whole is about half the combined values of copper, lead, and zinc
ores produced from the same States.
1.3 The natural radioactive decay of uranium leads to the for-
mation of various radioactive nuclides in ore bodies; one of which,
radon, is gaseous. Radon gas formed by the radioactive decay of
radium 226 escapes from exposed rock surfaces into the air of
uranium mines, where it continues to decay, generating a series of
other radioactive products commonly termed radon daughters.
Radon gas is also present in aboveground air in concentrations
that may vary with location, time of day, and weather conditions.
Some of the radon daughters contained in the air breathed by min-
ers are known to be deposited, retained, and to irradiate tissues in
the miner's respiratory system. Studies by the U.S. Public Health
Service in cooperation with the Atomic Energy Commission and
State agencies disclose that underground uranium miners are sub-
ject to lung cancer to a degree substantially greater than the gen-
eral population, or of that in miners in other kinds of underground
mines. The excess incidence apparently is related to the uranium
-------
1224 LEGAL COMPILATION—RADIATION
miner's occupational environment, and is believed to be induced by
the radioactive decay of radon daughters in the respiratory system.
1.4 Emphasis is focused on the radiation hazards associated
with underground uranium mining, since control is more difficult
than that which can be achieved in open pit mining or in subse-
quent milling operations. Open pit mining, being an aboveground
operation, presents no special problems in radiation protection.
Primary attention is given in this report to the evaluation of radia-
[P-1]
tion hazards resulting from the inhalation of radon and radon
daughters in the confines of underground mines and methods by
which these hazards can be controlled. In making this review, it
is recognized that the benefit derived by the application of progres-
sively more stringent control requirements must be evaluated in
light of the resulting reduction in radiation risk and the total im-
pact of the more stringent controls.
1.5 In addition to the recognized authority of the States to
establish health and safety standards for mining operations con-
ducted within their respective jurisdictions, responsibilities have
been designated to certain Federal agencies. They include the De-
partment of the Interior in the administration of the Federal
Metal and Nonmetallic Mine Safety Act; the Department of Labor
in the administration of the Walsh-Healey Act; the Department
of Health, Education, and Welfare in providing technical advice
in the matter of health standards and control of health hazards;
and the Atomic Energy Commission in the regulation of source
material (i.e., uranium and thorium), after removal from the
place of deposit in nature. States, Federal agencies, and the min-
ing industry all have a direct interest in the development of uni-
form standards applicable to the practical problems of uranium
mining, including a standard for radiation protection.
1.6 In the preparation of this staff report technical experts
from various Federal and State agencies, industry, and individual
nongovernment scientists assisted in developing information con-
cerning mining practices, economic aspects of uranium mining,
epidemiological evidence for associating adverse health effects
with radon daughter concentrations in mine atmospheres, and
considerations involving basic radiobiological mechanisms and
the absorbed dose to tissue resulting from breathing mine atmos-
pheres. Coordination of information between the staff of the
Federal Radiation Council, the National Council on Radiation Pro-
tection and Measurements, the USA Standards Institute (formerly
called the American Standards Association), and the Atomic In-
dustrial Forum was achieved by including individuals associated
-------
GUIDELINES AND REPORTS 1225
with these organizations in the FRC task groups. In addition, the
staff has had the benefit of consulting with representatives of or-
ganized labor, members of the International Commission on Radio-
logical Protection, and with individuals in other countries where
uranium is mined.
1.7 The Federal Radiation Council Working Group, which con-
sists of senior technical personnel from the agencies comprising
the Council, has supplied advice and information from their re-
spective agencies for inclusion in the report. Personnel from the
U.S. Bureau of Mines, Department of Interior, also have actively
participated in the preparation of this report.
SCOPE OF URANIUM MINING INDUSTRY
Production
1.8 The domestic uranium mines in 1966 produced approxi-
mately 50 percent as much uranium ore as was produced in 1961,
the year when the industry was at its peak. This curtailed rate is
due to a stretch-out of Government procurement contracts de-
signed to balance procurement with requirements and to tide the
industry over an interim period between diminishing Government
needs and the developing needs for the electric power industry.
Procurement under the remaining Government contracts during
[p. 2]
the period July 1967 through 1970 is estimated at 28,300 tons of
U308. Procurement for electric power plants in this period will
be of the order of 18,000 tons of U30S.
1.9 The U.S. Atomic Energy Commission estimates that "by
1980 the United States will have between 120- and 170-million
kilowatts of electricity generated by nuclear power, with a mid-
range of this projection—about ISO-million kilowatts—the best
single estimate." (1) This estimate takes into account the grow-
ing demand -for electric power, engineering and economic factors,
and the current rapid acceptance of nuclear power. An increase
of this magnitude in nuclear power plant facilities will probably
require on the order of 250,000 tons of U30R over the 15-year
period from 1966 through 1980 inclusive, (2) taking into account
the pertinent factors of probable reactor types, sizes, and char-
acteristics, as well as enrichment factors and fuel economy. About
100-million tons of mined ore would be needed to provide this
quantity of uranium, assuming no major change in the U30S con-
tent of ore processed (currently about 0.23 percent U308). Al-
though this is in excess of presently known low cost domestic ore
reserves (economic at a price of $10 per pound of U30S), it is con-
-------
1226 LEGAL COMPILATION—RADIATION
sidered reasonable to expect that additional ore will be discovered
to keep pace with demand. The 1966 mining rate was 4.2-million
tons. To meet the estimated total 15-year requirement, this rate
is expected to rise to 16- to 18-million tons annually by 1980. The
accuracy of these future estimates, however, is subject to the pos-
sible effect of foreign trade in uranium.
1.10 A substantial fraction of the known uranium deposits can
be mined by the open pit method. Currently, about one-third of
the domestic ore production is derived from open pit mines, some
of which have been converted from shallow underground opera-
tions. Current technological developments tend to increase the
advantages of the open pit method and therefore to extend the
depth of economically recoverable deposits. On the other hand,
deposits discovered in the future are expected to be at progres-
sively increasing depths, so that the proportion of ore mined from
open pits during the next 15 years may be expected to decline
somewhat. Thus, underground ore production may, by 1980, rise
to somewhat over 12-million tons per year, or several times the
current underground mining rate.
1.11 Some perspective on the relative significance of uranium
mining to the States involved is provided by comparison with
copper, lead, and zinc mining. The latest comparative statistics
available appear in the 1965 issue of the U.S. Bureau of Mines
Minerals Yearbook. The total amount of copper, lead, and zinc ore
produced from mines located in the principal uranium-producing
States (New Mexico, Wyoming, Colorado, and Utah) was about
43-million tons, with a recoverable metal value of about $295 mil-
lion. In the same year these States produced 4 million tons of
uranium ore containing about $150 million worth of uranium.
EMPLOYMENT IN U.S. URANIUM MINES
1.12 The first recorded production of uranium-vanadium car-
notite-type ore in the United States was in 1898 from the Uravan
mining district, Montrose County, Colo. (3) Limited production
continued until about 1935 when demand for vanadium for use in
alloy steels increased the market for carnotite ores. Despite this
production uptrend, there was no sustained large-scale employ-
ment until after the Atomic Energy Act of 1946. The first price
schedule of the Atomic Energy Commission that became effective
April 9, 1948, launched a new major mining industry. Thereafter
[P. 3]
employment in uranium mines increased rapidly until 1961, when
it declined as a consequence of curtailed Government purchases.
-------
GUIDELINES AND REPORTS
1227
Open pit mining of uranium did not become significant until 1955.
The number of uranium mines providing ore during the years 1954
through 1966 and the corresponding employment figures are shown
in tables 1 and 2, respectively.
TABLE 1.—ESTIMATES OF THE NUMBER OF MINES PRODUCING URANIUM ORE DURING THE CALENDAR YEAR
AS REPORTED BY THE INDUSTRY TO THE U.S. BUREAU OF MINES (1954-64) AND AEC (1965-66)
Year
1954
1955
1956
1957
1958
1959
1960
Underground mines
450
600
700
850
850
801
703
Open pit
mines
50
75
100
125
200
165
166
Year
1961 .
1962 .
1963 .
1964
1965
1966
Underground mines
497
545
573
471
562
533
Open pit
mines
122
139
162
106
74
88
TABLE 2.—NUMBER OF MEN EMPLOYED IN URANIUM MINES
Year
1954
1955
1956 .
1957
1958
1959
1960
Underground Mines •
916
1 376
1 770
2 430
2 796
3,996
4,908
Open pit
mines
53
293
584
574
1 175
1 259
1 499
Year
1961
1962
1963
1964
1965
1966
Underground Mines •
4 182
4 174
3 510
3 249
2 900
2,545
Open pit
mines
1 047
1 074
886
726
700
359
• Excludes aboveground employees who may occasionally go underground.
1.13 Some further perspective is provided by considering the
number of underground miners related to the size of mine. The
categories selected for this purpose are: (1) mines employing 15
or fewer men (2) those employing from 16 to 50 and (3) those
with more than 50. The data assembled in table 1-52 of U.S.
Bureau of Mines report, "Health and Safety Study of Metal and
Nonmetal Mines" (4) for 1963; are as follows:
Number of men
per mine
15 or less ... .
16 to 50
More than 50
Percent of
mines
60
27
13
Percent of
men
16
32
52
[P-4]
1.14 During 1966 a total of 621 mines produced ore, but the
number in operation at any one time probably did not average
-------
1228 LEGAL COMPILATION—RADIATION
more than 400. Underground mines account for the variability;
the number of producing open pit mines was fairly constant at
about 80. The number of underground miners involved was prob-
ably less variable than the number of operating mines because
men customarily move from one mine to another when mine op-
erations are intermittent. Many uranium miners have worked
previously in nonuranium mines; conversely, uranium miners often
quit uranium mines to work in nonuranium mines. The turnover
rate in the work force is therefore difficult to evaluate. However,
in a group of 1,888 uranium miners identified in a 1954 survey
made by the U.S. Public Health Service, only 26 percent were
found still working in uranium mines 6 years later. It is also esti-
mated that less than 1 percent work longer than 15 years in uran-
ium mines.
HEALTH AND SAFETY HAZARDS OTHER THAN RADIATION IN
URANIUM MINING
INJURY EXPERIENCE
1.15 The hazards of traumatic injury associated with mining
are commonly recognized. Although there are wide variations in
the frequency and severity of accidents within the industry, min-
ers as a group are exposed to serious risks. Experience in the
metal mining industry shows that injury rates have been reduced
to less than half over the last 30 years but, nevertheless, current
injury rates remain about four times the average of all manu-
facturing industries. (4)
1.16 Uranium mining became prominent at a time after the in-
jury rate in metal mines had been substantially reduced, but the
rapid growth of uranium mining, and the fact that much of it
was concentrated in areas remote from other metal mines, neces-
sitated the employment of some inexperienced miners. The injury
rate in uranium mines during the late 1950's was as high as that
experienced in other metal mines 15 to 20 years earlier. Since
1960, however, experience in uranium mines has improved
significantly.
PHYSICAL HAZARDS
1.17 U.S. Bureau of Mines records show that most disabling
work injuries occurring in underground uranium mines arise from
machinery, haulage, handling of materials, falls of persons, and
falls of ground. Fatal injuries have resulted primarily from ex-
plosives, haulage, and falls of ground. This has also been the
experience in other underground metal mines. The fatal ac-
-------
GUIDELINES AND REPORTS 1229
cident rate in underground uranium mines during 1965 averaged
about 1.93 per million man hours. (5)
ENVIRONMENTAL HEALTH HAZARDS IN UNDERGROUND MINES
1.18 The quality of the atmosphere in underground mines is of
primary importance to the health and safety of underground
workers. The mine atmosphere is subject to contamination by
harmful dusts and gases. Such contamination might result from
drilling (dust), blasting (gases and dust), materials handling
(dust), use of diesel engines (exhaust gases), emission of strata
gases, welding and cutting, and from mine fires. In uranium
mines and some other types of mines the radiation environment
must also be considered (see sec. II). In general, appropriate
measures used to control the hazards owing to common dust and
gases will serve also to reduce concentrations of radioactive ma-
terials in the mine air.
[p. 5]
1.19 Most uranium ore is mined from sandstone that contains
free silica, the causative agent of silicosis. (6) Surveys in uranium
mines having highly siliceous ores indicate that effective dust con-
trol measures are necessary to restrict the concentration of air-
borne dust to less than recommended limits. Wet drilling and
wetting of blasted material before and during loading and trans-
portation are normally supplemented by ventilation to the extent
required for effective control of dusts and gases. Toxic gases may
constitute a hazard to the health of mine workers if ventilation is
not adequate, or if men return to work areas before the gases
have been removed or sufficiently diluted by ventilation. Ventilat-
ing fans can provide positive means for controlling the volume and
flow of air underground. With a properly arranged duct system
fresh air can be delivered directly to work areas or, alternatively,
contaminated air can be withdrawn from such areas and delivered
above ground.
1.20 The use of diesel engines in underground mines necessi-
tates ventilation to dilute and remove toxic exhaust gases and to
replace oxygen consumed by combustion in engines. (7) Required
volumes of ventilating air for individual units are stipulated on ap-
proval plates of diesel-powered equipment approved by the U.S.
Bureau of Mines for use in underground mines.
1.21 Guides for limiting concentrations of gases, mineral dusts,
and airborne contaminants—other than radioactive substances
that are likely to be encountered in underground atmospheres—are
published annually by the American Conference of Governmental
-------
1230 LEGAL COMPILATION—RADIATION
Industrial Hygienists. These threshold limits are widely used by
engineers, inspectors, and regulatory agencies as guides for con-
trolling underground atmospheric environments. These values
represent conditions under which it is believed that nearly all
workers may be repeatedly exposed without adverse effect. The
concept of threshold limits is not used in radiation protection.
1.22 Control of temperature is an important factor in the opera-
tion of ventilation systems in underground uranium mines, par-
ticularly in cold climates. Incoming fresh air is often heated to
prevent freezing of pipes and to prevent icing problems in shafts
and haulageways.
[p. 6]
REFERENCES
(1) Seaborg, G. T. Fast Breeder Power Reactors—A World Outlook. Annual
Meeting of the Canadian Nuclear Association; Montreal, Quebec, Canada,
May 31, 1967.
(2) Nininger, R. D. World Production and Reserves of Uranium. Twelfth
Annual Minerals Symposium; American Institute of Mining, Metallurgical
and Petroleum Engineers; Moab, Utah, June 23, 1967.
(3) Coffin, R. C. Radium, Uranium, and Vanadium Deposits of Southwestern
Colorado. Colo. Geol. Survey Bull. 16, 1921.
(4) Report to Congress by the Secretary of the Interior. Health and Safety of
Metal and Nonmetal Mines (Submitted in response to PL 87-300, 75 Stat.
649), 1963.
(5) Injury Experience, Employment, and Worktime in the Mineral Industries
1964-65. U.S. Bureau of Mines Mineral Industry Survey, August 1966.
(6) USPHS Pub. 1076. Silicosis in the Metal Mining Industry—Reevaluation
1958-61 (USPHS and Bureau Mines), 1963.
(7) Holtz, John C. Safety with Mobile Diesel-Powered Equipment Under-
ground. U.S. Bureau of Mines Report of Investigations, No. 5616, 1960.
[p. 7]
-------
GUIDELINES AND REPORTS 1231
SECTION II
THE RADIATION ENVIRONMENT ASSOCIATED WITH URANIUM MINING
2.1 The atmosphere in underground uranium mines will nor-
mally contain a number of contaminants capable of producing
various deleterious effects in the respiratory system. These en-
tities include:
1. Airborne dust particles: Silica, alkaline earth and other metal carbonates,
silicates, vanadates and aluminates with smaller amounts of iron, molybdenum,
and uranium minerals—including the radioactive uranium decay products,
notably radium 226. Thorium and its radioactive decay products might also
be present in minor amounts. Atoms of the radon decay products rapidly
become attached to these particles (see par. 2.5).
2. The radioactive gas radon (and thoron if thorium is present).
3. Free ions: Single atoms of the radioactive elements resulting from the
decay of radon, e.g., polonium 218 (RaA), the first decay product of radon 222.
Other free ions may be formed by the radioactive decay of a free polonium 218
atom, or may be ejected by recoil of a decay product from the surface of a
larger particle and other mine surfaces.
4. Nuclei: Aggregations of a few molecules (e.g., water molecules) around a
polonium 218 atom or other decay product, or solid particles so small that diffu-
sion is the dominant transport mechanism.
2.2 The naturally occurring radionuclide uranium 238 is the
parent of the radioactive decay chain in which radon 222 is found.
Table 3 presents the principal components of the uranium series.
The parallel branches in the chain from polonium 218 to astatine
218 and from bismuth 214 to thallium 210 have been omitted;
only the energies of the alpha particles of interest are shown.
Natural thorium sometimes occurs as a constituent of uranium
ore, but in domestic ores it is generally less than 1 percent by
weight of the uranium content.
2.3 External gamma radiation intensities in domestic uranium
mines seldom exceed 2.5 mR per hour, (1) and the average in-
tensities are only a fraction of this. It is accordingly unlikely that
uranium miners will be exposed to external whole-body radiation
doses as large as the Radiation Protection Guide (RPG) recom-
mended by the FRC for occupational radiation exposure (5 rems
per year). However, in mining occasional high grade ore pockets
(5 percent or greater U30S) external radiation levels may neces-
sitate limitation of personnel exposure. Beta radiation intensities
near broken ores may be higher than gamma intensities by a factor
of 10, (2) but are of relatively minor importance as an external
radiation hazard under mining conditions.
[p. 9]
-------
1232
LEGAL COMPILATION—RADIATION
TABLE 3.—THE URANIUM SERIES
Isotope Symbol
Uranium 238 . . 2
Thorium 234 . 2
Protactinium 234 . 2
Uranium 234 2
Thorium 230 2
Radium 226 2
Radon 222 2
Polonium 218 2
Lead 214 2
Bismuth 214 2
Polonium 214 . 2
Lead 210 ... 2
Bismuth 210 .. 2
Polonium 210 2
Lead 206 . . 2
=U
"Th
"Pa
*U
°Th
6Ra
2Rn
«Po
"Pb
4Bi
"Po
°Pb
°Bi
opo
Historical
name
Uranium 1
Uranium Xi
Uranium X2
Uranium II
Ionium
Radium
Radon
Radium A
Radium B
Radium C
Radium Ci
Radium D
Radium E
Radium F
Radium G
Half-life
4.5 X 10' yrs
24.1 days
1.18 mins
2.50 X 10s yrs
7.6 X 10' yrs
1620 yrs
3.82 days
3.05 mins
26.8 mins
19.7 mins
164 x 10-' sec
22.0 yrs
5.0 days
138.4 days
Stable
Radiation
a
0,7
0,7
0,7
a
a, 7
a
a
0,7
a
0,7
0
a
Alpha
energy
(MeV)
5.49
6.00
7.69
5.30
Radon and Radon Daughters
2.4 Radon 222 results from the radioactive decay of radium
226. Being an inert gas it diffuses readily through the interstices
of rock to the rock face and from there into the air of the mine
spaces. It has been observed that the rate of radon diffusion into
the mine air varies inversely with changes in the barometric pres-
sure. As noted in table 3, the half-lives of the first four succes-
sive daughters of radon are short. Under static conditions (quiet
air) radioactive equilibrium will develop in about three hours.
However, an equilibrium state is seldom found in an actively
worked uranium mine area where fresh air is being continually
brought into the mine. The amount of fresh air that is brought
into a mine affects the concentration of the radon daughter prod-
ucts more than it affects the concentration of radon. The radon
daughter concentration in the air is reduced by dilution and by
adherence to dust particles and by preferential deposition on mine
walls, whereas additional radon is diffusing into the air from the
rock surfaces and from mine water.
2.5 Laboratory experiments have demonstrated that the unat-
tached daughter products of radon 222 exhibit a high rate of dif-
fusion in air; (3) that they quickly become attached to moisture
or dust particles suspended in the air (the mean lifetime existence
as free unattached ions is of the order of 10 to 50 seconds),(3)
and that the human respiratory system retains a substantial por-
tion of radon daughters attached to moisture or dust particles and
virtually all of the unattached portion. (4)
[p. 10]
-------
GUIDELINES AND REPORTS 1233
2.6 The principal dose to lungs of uranium miners is generally
attributed to the alpha particles emitted by the decay of the radon
daughter products. In most United States uranium mines the con-
centration of radon daughters is obtained by using a specific field
method of measurement, and the result is compared to the "Work-
ing Level" (WL), which is defined as any combination of radon
daughters in 1 liter of air that will result in the ultimate emission
of 1.3 X 105 MeV of potential alpha energy. (5) The numerical
value of the WL is derived from the alpha energy released by the
total decay of the short-lived radon daughter products at radio-
active equilibrium with 100 picocuries (pCi) radon 222 per liter
of air. The 100 pCi of polonium 218 give 1.3 X 104 MeV from the
total decay of the polonium 218 and the same number of terminal
polonium 214 atoms. The 100 pCi of lead 214 give 6.6 X 104 MeV
from the decay of the resultant polonium 214. The 100 pCi of
bismuth 214 give 4.8 X 10' MeV from the resultant polonium 214.
The resultant total is 1.27 X 105 MeV which is rounded to 1.3 X
105 MeV.
2.7 A significant advantage in the concept of the WL it its prac-
tical application to field measurements of the radon daughter
concentrations in mine air. The method of measuring the concen-
tration of decay products in terms of total alpha particle emission
is widely used for control and regulatory purposes. Exposure of
an individual to radon daughters in air can be estimated from the
length of time the individual breathes an atmosphere containing a
stated burden of radon daughters. The Public Health Service
publications usually express exposures as "Working Level Months"
(WLM), although other time periods are sometimes used. In-
halation of air with a concentration of 1 WL of radon daughters
for 170 working hours results in an exposure of 1 WLM.
2.8 Historically, radon daughter measurements have been made
in the United States uranium mines since about 1950, and the rec-
ords are preserved in large part by the U.S. Public Health Service
Occupational Health Field Station in Salt Lake City, Utah. Since
about 1960 similar records also have been kept by State regulatory
agencies. The records maintained by the USPHS Occupational
Health Field Station comprise such items as mine identity and
location, identification of personnel working underground at the
time of the survey, location of sampled mine areas, and concentra-
tions of radon daughters in mine air expressed in terms of the WL.
From time to time this agency has made summaries of these rec-
ords available for public purposes. The summaries generally dis-
play WL data averaged on a calendar year basis prior to 1962.
For subsequent years the reported averages use data for the third
-------
1234 LEGAL COMPILATION—RADIATION
calendar quarter. The data are further detailed according to the
State in which the mine is located; the States of main concern
being New Mexico, Wyoming, Colorado, Utah, and Arizona. Ura-
nium mines located in these States produced more than 90 percent
of the total domestic uranium ore in 1966.
2.9 Table 4 presents a summary derived from records of radon
daughter measurements in underground uranium mines prior to
1960. The table shows the number of mines measured and the
percentage of mines with radon daughter concentrations falling in
various ranges of WL values. These percentages are estimated
to be about the same as the percentage of the work force whose
annual average exposures fall within the WL ranges shown in the
table, and are considered to reflect the status of the whole industry
during that period of time.
[P. 11]
TABLE 4.—ESTIMATED DISTRIBUTION OF MINES BY WORKING LEVEL RANGES FROM 1956 THROUGH 1959
Year
1956
1957
1958
1959 ....
Number
mines
measured
108
158
.... 53
237
WL
19
20
28
18
1.0-2.9
WL
25
26
21
26
3.0-10.0
WL
33
28
36
28
>10.0
WL
23
26
15
28
Total
100
100
100
100
2.10 This breakdown suggests that about one-fourth of the work
force was probably exposed to atmospheres leading to annual ex-
posures larger than 10 WL, and about one-fifth was exposed at
average levels lower than 1 WL. It is also noteworthy that the
number of mines surveyed between 1956 and 1959 was but a
small fraction of the total uranium mines. This low coverage was
due to the common event that many small mines were not in op-
eration at the time of the survey. Many such mines were located
in remote areas and operated only a few weeks or months in each
year because of such factors as available ore, operating funds,
labor supply, weather, and so forth.
2.11 In December 1960 a Governor's conference on health
hazards in uranium mines(6) was held in Denver, Colo. This was
an outgrowth of interagency studies on the occupational health
problems of uranium miners carried out by the Public Health
Service, the Atomic Energy Commission, the U.S. Bureau of
Mines, and the Department of Labor. The objectives of the con-
ference were to present to the Governors of States engaged in
uranium mining, data on the prevailing radon daughter levels,
-------
GUIDELINES AND REPORTS 1235
such as those indicated in table 4; to present Information on ex-
perience in controlling radiation hazards; and to assist in develop-
ing cooperative programs to reduce radiation hazards in uranium
mines. As a result of this conference, many of the States placed
more emphasis on their mine inspection programs.
2.12 As a measure of the prevailing levels of radon daughters in
the mines, table 5 indicates the results of samples taken in the third
calendar quarter of 1965 and 1966. These data indicate consider-
able success in reducing concentrations of radon daughters. The
mine operating companies are cooperating with State regulatory
agencies to improve control of radon daughter concentrations in
working areas of the mines. The possibility of further reduction
in the mines reporting average WL values between 1 and 10 in-
volves considerations discussed in section IV.
2.13 The significance of these recorded data is limited by several
considerations: (1) individual WL measurements usually rep-
resent a 10-minute sample at a selected location; (2) the number
of samples taken per survey is restricted by the number of survey
personnel that can be accommodated in an operating mine and by
the man hours available to collect and analyze the individual sam-
ples; and (3) the frequency of surveys in individual mines varied
widely; a single survey per year was common practice in some
states, while in others surveys were even less frequent.
2.14 The U.S. Bureau of Mines carried out a study in 1962 on a
modification of the usual practice in selecting locations to be
sampled in a mine. The report on this project(7) indicates that
an estimate of the time-weighted assessment of miner occupancy
[p. 12]
-------
1236
LEGAL COMPILATION—RADIATION
TABLE 5—SUMMARY OF RADON DAUGHTER CONCENTRATIONS BY WORKING LEVEL RANGES DURING THE
THIRD QUARTER OF 1965 AND 1966
1965
Number
Percent of mines in each WL range
Arizona
Colorado
New Mexico
Utah
Wyoming
Total
State
Arizona
Colorado
New Mexico
Utah
Wyoming
Total
16
.... 124
26
47
16
229
Number
14
148
23
33
13
.. .. 231
50
39
15
49
44
39
1966
<1 0
57
45
17
55
38
44
1.0-2.9
19
42
38
43
56
41
Percent
1.0-2.9
29
42
47
39
54
42
3.0-4.9
12
12
42
4
13
of mines
3.0-4.9
14
7
30
8
9
5.0-10.0
19
6
5
4
6
in each WL
5.0-10.0
5
6
6
4
>10.0
1
1
range
>10.0
1
1
in spot-sampled areas permits an approximate evaluation of the
exposure of individuals for the day of sampling. The report in-
dicates that as few as four area samples may be sufficient to eval-
uate the exposure of an individual with a probable accuracy of
±25 percent. The examples cited in the Bureau report illustrate
the method: (1) a miner working in various areas having con-
centrations ranging from 3.7 to 8.0 WL had an estimated weighted
exposure of 6.1 WL, (2) another miner working in concentrations
ranging from 0.3 to 6.4 WL had a weighted exposure of 1.0 WL,
and (3) a third one working in concentrations of 0.2 to 1.4 WL had
a weighted exposure of 0.5 WL. The results of this study suggest
that the arithmetic average of concentrations found in the mine
air does not give a reliable estimate of exposure. Similarly, the
maximum concentration found in any representative mine sam-
pling bears no direct relation to the exposure of individual miners.
2.15 Time-weighted assessment for evaluating exposures in
uranium mines has not been generally adopted for regulatory pur-
poses. Rather, pertinent State regulations and the recommenda-
tions of the USA Standards Institute stipulate a maximum
concentration that, when exceeded, is used as a basis for closing
the mine area concerned. Two of the five States (Colorado and
New Mexico), for which data are reported in tables 4 and 5, main-
[p. 13]
-------
GUIDELINES AND REPORTS 1237
tain records both of concentrations found at each inspection and
of the estimated time-weighted average exposure of individual
workers who work in different areas in the mines.
2.16 Radon and its daughter products have also been measured
in other than uranium mines. One study(8) showed that the air
in certain nonuranium mines contained radon daughters in con-
centrations of about 0.1 to 0.2 WL. Jacoe(9) reported radon
daughter concentrations in 24 nonuranium metal mines in Col-
orado ranging up to 2.0 WL, and a similar range in five clay
mines. Rabson, et al.,(10) reported on radon daughter concen-
trations in the gold mines of South Africa. In five of these mines,
which also contain uranium, radon daughter concentrations av-
eraged between 0.1 and 0.9 WL with maximum concentrations up
to 4 WL. The existence of relatively high concentrations of radon
in water and air in Canadian fluorspar mines has been re-
ported. (11) The authors found individual samples in unused
spaces higher than 10 WL, and estimated that average mine air
concentrations ranged from 2.5 to 10 WL.
[p. 14]
REFERENCES
(1) Eeport to Congress by Secretary of the Interior. Health and Safety of
Metal and Nonmetal Mines (submitted in response to PL 87-300, 75 Stat.
649), 1963.
(2) Harris, W. B., et al. Environmental Hazards Associated with Milling
Uranium Ore. AMA Archives Ind. Health, Vol. 20, pp. 365-382, Nov. 1959.
(3) Chamberlain, A. C., and Dyson, E. C. The Dose to Trachea and Bronchi
From Decay Products. British Journal of Radiology, Vol. 29, p. 317, June
1956.
(4) Shapiro, J. An Evaluation of the Pulmonary Radiation Dosage From
Radon and Its Daughter Products. University of Rochester Atomic Energy
Project, UR-298, April 1954.
(5) USPHS Pub. 494. Control of Radon and Daughters in Uranium Mines
and Calculations on Biologic Effects, 1957.
(6) USPHS Pub. 843. Governors' Conference on Health Hazards in Uranium
Mines—A Summary Report, 1961.
(7) U.S. Bureau of Mines Report RI 6106. Estimating Daily Exposures of
Underground Uranium Miners to Airborne Radon—Radon Daughter Prod-
ucts, 1962.
(8) Wagoner, J. K., et al. Unusual Cancer Mortality Among Group Under-
ground Metal Miners. N. Eng. J. Med., Vol. 269, No. 6, pp. 284-289, Aug.
1963.
-------
1288 LEGAL COMPILATION—RADIATION
(9) Jacoe, P. W. Occurrence of Radon in Nonuranium Mines in Colo. AMA
Archives Industrial Hygiene and Occup. Med., Vol. 8, p. 118, 1953.
(10) Rabson, S. R., et al. Experience in Measurement of Radon and Radon
Daughter Concentration S. African Uranium Mines. Proc. IAEA Sym-
posium Rad. Health and Safety Mining and Milling Nuclear Materials,
Vol. II, pp. 335-347, 1964.
(11) deVilliers, A. J., and Windish, J. P. Lung Cancer in Fluorspar Mining
Community. Brit. J. Ind. Med., Vol. 21, p. 94, 1964.
[p. 15]
SECTION III
BIOLOGICAL EFFECTS ASSOCIATED WITH EXPOSURE TO RADON AND
RADON DAUGHTERS WITH SPECIAL REFERENCE TO LUNG CANCER
3.1 When the mining of uranium-bearing ores began in the
United States in 1898 (1) it was known that radioactivity was
associated with the ore, but the potential health hazards from this
agent were not suspected until about 1921 when Uhlig(2) sug-
gested that the high numbers of lung cancers found among Schned-
berg miners might be due to ionizing radiation. From a knowledge
of radiobiology and of exposure conditions in uranium mine en-
vironments, one might expect the manifestation of radiation injury
in the respiratory tract to be of three basic types: tumors, atrophy
of functional tissue, and increased susceptibility to other disease
agents. Possible effects from external radiation and effects related
to the deposition of dust particles containing radionuclides on the
skin and in the eyes cannot be excluded. However, these radiation
doses are so minor in comparison to the doses to the respiratory
tract that they are not treated in this report.
Animal Experiments
3.2 Animal experiments have demonstrated that doses of ioniz-
ing radiation delivered to the lungs may reduce pulmonary dust
clearance, (3) produce emphysema, (4) cause loss of pulmonary
function, (5 6) and cause pulmonary neoplasia, fibrosis, or changes
in bronchial epithelium. (7-25) These experiments have explored
many parameters: (1) species—rats, mice, rabbits, dogs; (2)
radiation type—a, (3, y, x-rays; (3) internal and external radia-
tion; (4) relationships between response and dose rate or total
-------
GUIDELINES AND REPORTS 1239
dose; and (5) tumor types. Such experiments are useful to the
extent that they lead to sufficient insight into the mechanisms of
radiation-induced carcinogenesis to aid in the interpretation of
human experience. However, most of the pulmonary radiation
dose received by uranium miners is from alpha particles. Since
these particles have a very short range in tissue and are densely
ionizing (high linear energy transfer), the different spatial dis-
tribution of energy absorption in tissue limits the utility of dose-
effect relationships derived from animal experiments using beta,
gamma, or x-rays.
3.3 In general, it has not been possible to produce pulmonary
carcinomas in animals in a systematic way from controlled expo-
sure to radon or radon daughters, although several attempts have
been made.(26-28) Some animal experiments using radon alone,
in combination with varying amounts of its decay products, or in
combination with ore dusts, produced metaplasia of the bronchial
epithelium and a few pulmonary tumors. (13 29-32) The small
number of tumors and inadequate controls in some of the expe-
riments precludes drawing definite conclusions from them. The
administration of plutonium 239 (also an alpha emitter), in rela-
tively large doses, has induced pulmonary malignancy in addition
to severe lung damage in dogs. (12 33 34-)
[p. 17]
Mortality and Disease Patterns among Uranium Miners and Others
3.4 It has been known for many years that underground ura-
nium miners are subject to elevated mortality rates from accidents
and from lung disease. Accidental death rates among uranium
miners decreased over a period of years to a low of 1 per million
man hours in 1964, comparable to those of other underground
miners. (35) However data presented in paragraph 1.17 indicate
an accidental death rate of 1.93 per million man hours in 1965.
Elevated lung cancer rates have been reported among fluorspar
miners, (36) iron miners, (37 38) United States base metal min-
ers, (39) and the gold miners of Gwanda.(40) Other authors
report that no increase in lung cancer incidence was observed
among South African gold miners, (41 42) nor among British
coal miners. (43) The pneumoconioses (including silicosis with ac-
companying emphysema and cor pulmonale) found among most
groups of miners may have predisposed them to pulmonary in-
fections such as pneumonia and tuberculosis. The incidence of
disability from silicosis and related chest diseases appears to have
been markedly reduced by the use of modern industrial hygiene
techniques, the most important of which is ventilation. (44)
-------
1240 LEGAL COMPILATION—RADIATION
3.5 Several methods have been used to express epidemiological
findings in published papers. The two given below will be the
principal ones used in this report:
1. "Incidence" is the number of cases of a disease appearing in a stated
population per unit of time. Vital statistics are normally reported in terms of
annual incidence. Since lung cancer has a high case fatality rate, the incidence
of mortality is practically the same as the incidence of the disease.
2. "Mortality ratio" relates the number of observed deaths to the number
that would be expected in the same population if the mortality rates derived
from the vital statistics records in large populations were applicable. Calcula-
tion of the "expected" value must take into account such variables as age, sex,
race, and years at risk. Of all the malignant diseases, lung cancer is the most
common cause of death among males in the United States. The incidence of
lung cancer in the general population increases rapidly after age 40 and reaches
a peak around age 60. (45)
U.S. Uranium Miners
3.6 In 1950 the USPHS, in cooperation with other Federal and
State agencies, initiated a program to evaluate the health problems
inherent in the uranium mining industry. Miners were enrolled
in the study if they volunteered for at least one physical examina-
tion and provided social and occupational data in sufficient detail
to allow followup of their health status. Small numbers of men
were examined in 1950, 1951, and 1953. During 1954, and later,
attempts were made to examine as many men as could be located
and would cooperate. It has been estimated that in 1957 and 1960,
90 percent of the men working in the industry in the areas visited
were examined. (46)
3.7 Estimates were made of each man's exposure to radon
daughters, expressed in WLM (see para. 2.7), on the basis of his
occupational history and measurements of radon daughter levels
in mine air. Where such measurements were not available, the
probable value was estimated from measurements made in mines
of similar location, depth, ore type and grade, and ventilation ar-
rangements. The occupational history, including identification of
[p. 18]
particular mines and when the individual worked in each, depends
on individual recall rather than payroll records.
3.8 For various reasons the PHS study group does not represent
the entire mining population or a random sample thereof. This
complicates the evaluation of the number of lung cancers that
would be expected in the group from causes unrelated to exposure
to radon daughters in the mine atmosphere, since a bias resulting
from the voluntary method of selection is possible. This possibil-
ity was examined by the PHS in a previous analysis, and it was
-------
GUIDELINES AND REPORTS 1241
concluded that this factor, although present, did not affect the
general conclusions of that analysis. (46)
3.9 The total study group consists of approximately 5,000 under-
ground miners, uranium mill workers, and other types of above-
ground workers in the industry (both white and nonwhite) who
have had at least one physical examination under the program.
After examining the composition of the group enrolled in the PHS
study from different viewpoints, the analysis made for the Federal
Radiation Council focused on a subgroup of 1,981 white miners
who started underground uranium mining before July 1, 1955.
3.10 The number of lung cancers observed in the subgroup
selected for analysis was compared with the number that might be
expected based on examination of vital statistics records of the
male population of the States in which the miners worked (see
par. 3.5). For purposes of the analysis, person-years were divided
into categories according to increasing exposure to radon daugh-
ters expressed as cumulative WLM (see table 6).
3.11 As an example of the procedure, consider a subject who
was born in July 1900, and started underground uranium mining
in July 1950 in a mine where the atmosphere was estimated to
contain 10 WL of radon daughters in 1950 and each year there-
after. He mined full time until December 1957 and has not mined
since. In July 1954 this miner was first examined by a PHS team
and thereby entered the study group. For August and each suc-
ceeding month in 1954 he was assigned one person-month at risk
in the age group 50-54, WLM category C (360-839 WLM) and
the category for less than 5 years after he started underground
uranium mining. This individual was in comparable categories
during the first 6 months of 1955. However, in July 1955 he was
removed from the age group 50-54 and changed to age group 55-
59 years. Also, this individual was removed from the category of
less than 5 years since he started mining to the category of 5-9
years since he started mining. The 12 months at risk in 1956 and
the first 6 months of 1957 did not alter the category designations
for this particular individual. In July 1957 the calculated WLM
value reached 840 and thereafter the person-months were assigned
to category D (840-1,799 WLM) where he remained until the
cutoff date for the analysis (June 1965). If the individual had
died during this period, the month of death would have been used
to determine the last person-month at risk.
3.12 After this accounting procedure had been completed for
each member of the study group, the person-months were con-
verted into person-years at risk, classified by calendar year, age
group, WLM category, and time after the individual started under-
-------
1242 LEGAL COMPILATION—RADIATION
ground uranium mining. The expected number of lung cancer
deaths was then calculated for the person-years in each of these
categories. For example, in 1958 there were 16.59 person-years
in age group 45-49 and WLM category D (840-1,799) with 5-9
[p. 19]
years after the individuals started underground uranium mining.
The annual lung cancer rate for white males in this age group in
Colorado, Utah, New Mexico, and Arizona combined was 2.827
per 10,000 in that year. The term "lung cancer" is used in this
report to designate cancer of the lung or of other tissues of the
respiratory tract. The expected number of lung cancer deaths in
2 827
this particular group is therefore 16.59 X —'- or 0.0047. Ex-
10,000
pected numbers obtained in this way for all age groups and
calendar years in each exposure category were then added to ob-
tain the expectations shown in the analysis (see table 6).
3.13 A basic requirement for a comparison of the number of
lung cancers observed in the uranium miner group with the rates
in the general population is that the same criteria be used for in-
cluding a lung cancer death in the study group that were used in
deriving the basis for calculating the expected deaths, i.e., lung
cancer was listed on the death certificate as the underlying cause
of death. The analysis, shown in table 6, is the same as that ap-
pearing in table 8 of the preliminary draft issued May 1967, with
three additional columns—(1) the number of person-years at risk,
(2) the expected annual lung cancer mortality per 10,000 miners,
and (3) the calculated annual mortality per 10,000 miners. The
95 percent confidence limits for the observed mortality rates are
also shown. This information, expressed in terms of expected and
observed rates per 10,000 miners, is also shown graphically in
figure 1.
3.14 The analysis indicates the presence of a clear association
between exposure to radon daughters in mine air expressed as
cumulative WLM and the number of lung cancer deaths in the
study group. The 24 deaths observed versus 1.82 expected in
exposure categories D, E, and F, may be compared to 10 deaths
observed versus 3.31 expected in exposure categories A, B, and C.
As can be seen from figure 1, all of the lung cancer rates for
categories D, E, and F are significantly above the expected rate.
Even though the observed incidence for categories A, B, and C is
above that expected, only category B is significantly high and the
lack of a progressively increasing incidence fails to support a
causal role for radon daughter exposures at these levels. How-
ever, the absence of a steadily increasing incidence could easily be
-------
GUIDELINES AND REPORTS 1243
the result of chance alone, so that the data do not suggest or ex-
clude the existence of a threshold. Since the quantitative relation-
ship shown in table 6, and figure 1 may be, in part, a consequence
of the way exposure categories were selected, alternative break-
downs of 1,000 WLM categories in the upper range and of 250
WLM under 1,000 WLM were considered. These alternative
cumulative WLM exposure category designations for the 1,981
miners in table 6 were estimated from a random stratified sample
of 299 white underground uranium miners without lung cancer
and from the 49 cases of lung cancer. Examination of the ratios
of cases to estimated number of miners by exposure categories at
the end of 1963 suggests that the first clearly demonstrable excess
of lung cancer with progressively increasing risks at each higher
WLM level may be in a category somewhat above 1,000 WLM.
This is hardly surprising in view of the sampling variation which
might commonly occur with the small number of cases in most
categories. In any event the data are not sufficient to indicate
an association between exposure to radon daughters and the sub-
sequent development of lung cancer when the cumulative expo-
sures are less than about 1,000 WLM.
[P. 20]
-------
1244
LEGAL COMPILATION—RADIATION
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[p. 21]
-------
GUIDELINES AND REPORTS
1245
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280
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CUMULATIVE WLM
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FIGURE 1. — Observed and expected annual lung cancer mortality per 10,000
miners and 95-percent-confidence limits in relation to exposure (see par. 3.13
and table 6).
[p. 22]
3.15 Lung cancer is not an immediate effect of exposure to
radon daughters. The largest number of lung cancers observed
in all exposure categories appeared 10 or more years after the
individuals first started mining, even though several of the miners
-------
1246 LEGAL COMPILATION—EADIATION
worked underground only a few years in the uranium industry.
For this reason, another subgroup of 1,434 miners who started
mining after July 1, 1955 have not been included in the present
analysis. The estimated exposures of 114 miners in this subgroup
at the end of 1963 were 840 WLM or more. No lung cancers have
been reported from this higher exposure group versus an expected
0.09, although 3 have been reported in the lower exposure group
of 1,320 miners versus an expected number of 1.7.
3.16 The 34 observed deaths from lung cancer shown in table 6
are those that meet the requirements for group comparisons men-
tioned in paragraph 3.13 (i.e., the underlying cause of death was
recorded as lung cancer on the death certificate). Fifteen addi-
tional deaths from lung cancer make a total of 49 a observed in
the subgroup of 1,981 miners who began mining before July 1955.
These were not included in table 6 for one of two reasons: (1) the
"cause of death" was not listed as respiratory cancer on the death
certificate, or (2) the date of death was after June 1965, the cut-
off date for the mortality analysis. Five of these additional 15
cases occurred in the group of 63 miners whose recorded ex-
posures were greater than 3,720 WLM making a total of 12 in this
small group. The remaining 10 were about evenly distributed
among the other exposure groups. As related to the years since
the beginning of underground uranium mining, but without regard
to the exposure level, 3 appeared among miners with 5 to 9 years
elapsed time after the start of mining, and 12 after 10 or more
years had elapsed. Further evidence of a time factor is indicated
by the death of 26 individuals with lung cancer by the end of 1963,
and of 23 thereafter. The 49 cases may be considered as more
indicative of the real incidence of lung cancer in the study group,
although there is no generally accepted way to determine the ex-
pected value. Detailed information on the 49 cases will be found
in the transcript of the hearings conducted by the Joint Com-
mittee on Atomic Energy between May 9 and August 10, 1967.
Cell Type of Uranium Miners' Lung Cuncer
3.17 Although the malignant nature of the growths found at
autopsy in miners was recognized as early as 1879, it was not until
1926 that they were established as carcinoma. (47) As pointed
out by Gates and Warren,(9) the reason that they were initially
thought to be a form of lymphosarcoma is probably that most of
the cancers seen were of the small cell undifferentiated variety
* For the purposes of this discussion, the 34 deaths shown in table 6 will be referred to as "lung
cancer deaths" and the 15 additional deaths will be referrd to as "cases."
-------
GUIDELINES AND REPORTS 1247
which bears some resemblance to lymphosarcoma. Saccomanno
et al., (48) found that 57 percent of the lung cancers among United
States uranium miners were of the small cell undifferentiated va-
riety. The majority of these were considered by the authors to be
of the "oat cell" type. The authors also showed that the propor-
tion of small cell undifferentiated cancers among uranium miners
increased with the estimated exposure to radon daughters. Small
cell undifferentiated bronchial carcinoma rarely exceeds 20 percent
of lung cancers found among nonminers. (48 49) Although small
cell undifferentiated carcinoma or "oat cell" carcinoma of the lung
is described as the morphological type representative of the lung
cancers identified in uranium miners, it may be well to call atten-
[P. 23]
tion to the fact that bronchogenic (lung) cancers may vary ap-
preciably in cell type in different parts of the tumor and the
diagnosis of a specific cell type related to a specific causal agent is
subject to some caution.
Base Metal Miners
3.18 An elevated incidence of lung cancer has been reported
among miners of a sulfide ore that contained iron, copper, zinc,
lead, manganese, arsenic, antimony, calcium, fluorine, and sil-
ver. (39) The uranium-thorium content is not known but it was
probably about 1 percent of that in normal uranium ore. Wagoner,
et al., suggested several possible etiological factors, among which
was radiation from radon decay products. While being followed
for 25,033 person-years, this group experienced 47 lung cancer
deaths, approximately three times the expected number. The
radon daughter concentrations in those mines in 1958 were esti-
mated to have been in the range of 0.1 to 0.2 WL. The concen-
trations during earlier years before the advent of improved
ventilation are not known but were estimated to have been pos-
sibly 5 to 10 times higher. The threefold increase in the observed
numbers of lung cancers relative to those expected was attributed
by the authors not to be an effect of age, smoking, nativity, ur-
banization, socioeconomic status, heredity, diagnostic accuracy, or
silicosis. The authors concluded that it appeared likely that the
mine air contained materials that singly or in combination could
be carcinogenic. Wagoner et al., also concluded that chronic ex-
posure to radon or radon daughters alone is unlikely to account for
the observed increase, although there appeared to be a higher
percentage of undifferentiated cancers than in the comparison
group. (50)
-------
1248 LEGAL COMPILATION—RADIATION
Fluorspar Mines
3.19 deVilliers, Windish,(56) and Parsons, et al.,(51) have
made detailed studies on Newfoundland fluorspar miners. Al-
though uranium minerals could not be identified in the surrounding
rock, radon entered the mine in ground water. The average con-
centration of radon daughters in the mine air was estimated to
range between 2.5 and 10 WL. The group studied by deVilliers
and Windish contained 630 men who had worked 12 months or
more in the mines over a 29-year period (1933-61). Of 69 deaths
reported in the group, 26 were attributed to lung cancer. This
number is 25 to 40 times the number that might be expected if
the lung cancer rates in the study group were compared to those
of the adult male population of Newfoundland. (36) Lung cancer
deaths were not noted during the first 19 years of operation of the
mines.
Joachimsthal and Schneeberg Miners
3.20 Although mines in the Joachimsthal and Schneeberg areas
have been operated since about 1500 A.D., the excess mortality
was not generally attributed to lung cancer until the 1920 dec-
ade. (2 47 52) The radon 222 concentrations in the mine air were
estimated to have averaged between 3,000 and 15,000 pCi per liter
of air (53 54) (i.e., radon daughter concentrations of 30-150 WL
at radioactive equilibrium). The percent of deaths attributed to
lung cancer has been reported to vary between 30 and 70. (55 56)
Although knowledge about the population size and age distribution
of the miners is incomplete, it was estimated in the course of this
review that the incidence was possibly more than 20 times what
might have been expected.
[p. 24]
Relation to Other Agents and Disabilities
3.21 Analysis of medical histories of U.S. uranium miners ex-
amined in 1957 and in 1960 showed a greater prevalence of the
following complaints which are also observed in other miners:
(1) shortness of breath, (2) persistent cough, (3) history of
wheezing or whistling sounds in the chest, and (4) history of chest
pain or pressure in the chest. (51 57) Ventilatory function studies
made during these examinations showed that cumulative exposure
to the atmosphere in uranium mines contributes to a loss in ven-
tilatory function in a manner similar to that observed in aging and
from cigarette smoking. (51 58)
3.22 Since a relatively high percentage of United States ura-
nium miners smoke cigarettes and since cigarette smoking has
-------
GUIDELINES AND REPORTS 1249
been associated with an increased incidence of lung cancer, it is
necessary to consider this agent in the etiology of the lung cancers
of uranium miners. (60 61) Although United States uranium
miners smoke more than the general population, they smoke no
more than some other occupational groups whose lung cancer rate
is not comparable to that of uranium miners.(62) Since smoking
habits appear not to differ systematically among individuals as-
signed to the different cumulative exposure categories in table 6,
this variable is not considered important to the comparisons drawn
between groups in that table. The cigarette consumption of the
most highly exposed group was about the same as that of the less
exposed groups. Although cigarette smoking may affect the total
occurrence of lung cancer among uranium miners (i.e., cancers
observed compared to expected), smoking alone does not explain
the trend with cumulative WLM. An analysis made by the PHS
led to the conclusion that the smoking history of the uranium
miners might increase the expected number of lung cancers from
5.13 as shown in table 6 to about 7. The data neither prove nor
disprove the existence of a relationship between cigarette smoking
and radon daughter exposure in the etiology of lung cancer among
uranium miners.
3.23 There is evidence that cigarette smoking contributes mate-
rially to nonmalignant pulmonary impairments to which uranium
miners are subject.(57 58) Cigarette smoking can influence lung
cancer development among uranium miners in other ways—by
changing the radiation dose distribution (through alterations in
ciliary motion or thickness of the mucus blanket). It might act as
a mitotic stimulant to bronchial epithelium which could reduce
latent periods or influence the cell type of carcinoma produced.
Although cigarette smoking seems to increase the incidence of
several cell types of carcinoma, the one most prominently increased
is the epidermoid type. This is in contrast to the small cell un-
differentiated type which has been reported to be most prominently
increased among uranium miners.(48) The possibility that a sy-
nergistic relationship may exist between cigarette smoking and
exposure to radon daughters needs further study.
3.24 Increased incidence of lung cancer among miners has at
times been attributed to silicosis. However, a number of studies
suggest that silicosis by itself does not necessarily predispose to
lung cancer. (56 63 64) The prevalence of silicosis among United
States uranium miners has been reported to be comparable to that
among other United States metal miners,(44) but lung cancer
rates of the two groups are quite different.
3.25 The observations described in the previous paragraphs are
-------
1250 LEGAL COMPILATION—RADIATION
consistent with the older observations from Schneeberg and
Joachimsthal that many miners had silicosis and tuberculosis (47
56 59) although Pirchan and Sikl reported that no notable degree
of anthracosis or silicosis was found in the lungs of Joachimsthal
[P. 25]
miners submitted to autopsy. (52) Miners have undoubtedly ex-
perienced parenchymal pulmonary damage from exposure to the
atmosphere in uranium mines as well as in other types of mines,
quite aside from induced lung cancer. What portion of this par-
enchymal damage is due to radiation and what portion is due to
nonradioactive dust (such as free silica) cannot be determined at
this time, but it seems possible that sufficient exposure to radon
daughters may enhance and alter the fibrogenic response to silica,
and may possibly exert a fibrogenic effect of its own.
3.26 Among the many items considered in assessing the etiology
of the Schneeberg and Joachimsthal lung cancers was the possible
role of heredity. (56 59 63) Since both mining areas were rel-
atively isolated, it was felt that centuries of inbreeding might
have resulted in a high lung cancer strain of people as has occurred
among certain strains of mice. (65-67) Although this was a pos-
sibility, the development of such high rates of lung cancer has
never been observed among isolated nonmining populations. The
fluorspar miners mentioned in paragraph 3.19 also constituted a
relatively isolated population, but it was noted that a nearby
similarly isolated community at Grand Banks, which did no min-
ing, had a low lung cancer rate. (36) It has also been noted that
high lung cancer rates have been observed primarily in males of
the population. Among U.S. uranium miners, where marked dif-
ferences in lung cancer rates have been shown between different
cohorts, (46) and different exposure groups, (60) there is no reason
to believe that hereditary factors were significantly different
among the groups. There is no basis on which to implicate a
common genetic factor as an important contributor to lung cancer
in United States uranium miners.
3.27 The presence of long-lived radioactive materials in the dust
of uranium mines (68) has given rise to speculation that these
may contribute to the lung cancer rate of uranium miners. The
various isotopes of uranium, thorium, and radium have been the
principal radionuclides considered. In uranium ores, the relative
abundance of these nuclides is generally low. Their concentration
in mine dust is therefore a function of the richness of the ore.
Uranium determinations on miners' urine have indicated that
uranium is not absorbed in sufficient amounts to present a toxic
hazard.(69) Thorium isotopes might be expected to concentrate
-------
GUIDELINES AND REPORTS 1251
in lymph nodes, spleen, liver, lung, and bone. (73) Radium iso-
topes would be expected to concentrate in bone. However, no
radium could be detected by whole-body counting in several ura-
nium mill workers who had been heavily exposed to ore dust. (70)
All the radionuclides in the uranium decay series undoubtedly con-
tribute something to the radiation dose of uranium miners, and
there is some indication that thorium 230 may have a longer pul-
monary retention than its parent uranium. (71 73) However, the
contribution by the immediate daughters of radon is so great that
the contribution by other radionuclides to the lung dose during the
working years is probably negligible by comparison.
3.28 Since carcinogenic hydrocarbons have been observed to be
present in the exhaust from diesel engines, (72) there is the pos-
sibility that exposure to the exhaust gases might increase the
incidence of lung cancers in uranium miners. There were no diesel
engines in the Schneeberg and Joachimsthal mines during the pe-
riods when high lung cancer rates were noted. Beginning about
1952 a substantial part of United States production of uranium
ore has involved underground diesel equipment. Many of the
United States uranium miners in the present study who developed
lung cancer had relatively little exposure to diesel fumes in their
early work experience. In many nonuranium mines diesel equip-
[p. 26]
ment has been used underground for as long as, or longer than in
uranium mines. Gasoline engines are rarely, if ever, used under-
ground.
3.29 Circumstantial evidence appears to rule out diesel exhaust
as an important agent responsible for the observed increase of lung
cancer rates among uranium miners. However, since diesel
exhaust contains the same type of carcinogens as cigarette
smoke, (72) it is entirely possible that diesel smoke might con-
tribute in the manner discussed above with respect to cigarettes
(pars. 3.22 and 3.23).
Discussion and Conclusions
3.30 Respiratory impairment of several varieties has, for many
years, been a recognized hazard of underground mining. Analysis
of available evidence permits the conclusion that sufficient expo-
sure to radon 222 and its short-lived radioactive daughters in the
mine atmospheres is associated with an increased incidence of lung
cancer. The highest incidence of lung cancer is occurring now in
the group of miners (1) who worked in mines in which the average
concentration of radon daughters was usually higher than 10 WL;
-------
1252 LEGAL COMPILATION—EADIATION
(2) whose total cumulative exposures ranged upward from about
1,000 WLM; (3) who started mining uranium ore more than 10
years ago; and (4) who were moderate to heavy cigarette smokers.
These observations suggest that additional cases of lung cancer
can be expected to develop in the study group.
3.31 The USPHS epidemiological study was designed to identify
possible etiologic agents that might be implicated as a reason for
the high incidence of lung cancer observed among the uranium
miners. Observations on the United States uranium miners who
started underground mining before July 1955 clearly demonstrate
that an association exists between exposure to radon daughters
and a higher than expected incidence of lung cancer when cumula-
tive exposures are more than about 1,000 WLM. The degree of
risk at lower levels of cumulative exposure cannot be determined
from currently available epidomiological data. It is prudent to
assume, however, that some degree of risk exists at any level of
exposure, even though effects may not now be evident at the lower
levels of cumulative exposure.
3.32 A review of the epidemiological data conducted by the
USPHS after the preliminary report 8 was issued in May 1967,
and testimony provided to the Joint Committee on Atomic Energy,
amplify the previously described uncertainties in the exposure
data and their interpretation. (74) These include:
1. The early measurements were very infrequent (sometimes less than once
a year) and sampling sites were selected for purposes of control.
2. Information about the mines in which each individual had worked, in-
cluding the year and the number of months in each, was obtained from an
interview with each miner several years later.
3. The information in table 6 is based on estimates of the months worked
in underground uranium mines only. Many of the miners also had extensive
experience in other underground mines where radon daughters were present,
but at lower concentrations. Present evidence suggests that underground
uranium mining may account for less than one-half of the total exposure to
radon daughters that might be associated with the complete mining experience
of the individual when the WLM assigned to underground uranium mining is
[p. 27]
in exposure categories A or B (i.e., less than 360 WLM).74 The addition of
exposure experience in other underground mines could result in some redis-
tribution of the 34 lung cancer cases in table 6.
4. The miners in the study group started underground uranium mining
before 1955, when radon daughter concentrations up to several hundred WL
were commonly found in individual samples. Other factors taken alone (i.e.,
ore dust, blasting gases, and other noxious agents) do not seem to be impli-
cated as etiological agents for the lung cancers found in underground uranium
miners. However, these factors, together with smoking, can influence any
quantitative relationship between exposure to radon daughters and the prob-
-------
GUIDELINES AND REPORTS 1253
ability of developing lung cancer by their individual or collective effects on
lung tissue.
3.33 Several dosimetry models have been developed in an at-
tempt to derive a numerical estimate of the effective radiation dose
to the lung that might result from exposure to a given concentra-
tion of radon and radon daughters. Details of some of these
models are presented in the appendix of this report. The differ-
ences among the various models and the uncertainties in the basic
radiological parameters that must be used are too large for the
models to be acceptable at the present time as a basis for estimat-
ing the risk of radiation-induced carcinogenesis. Inference of risk
drawn from epidemiological studies of lung cancers associated
with exposure to various concentrations of radon and its daughter
products appears to be the most satisfactory basis for evaluating
the associated lung cancer risk at the present time, although no
reliable quantitative statement can be made if cumulative expo-
sures are less than about 1,000 WLM.
[p. 28]
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mitted to the Joint Committee on Atomic Energy, 1967.
[p. 32]
SECTION IV
CONTROL CAPABILITIES IN URANIUM MINES
4.1 Several procedures are available to control exposure of
miners to radon and its radioactive daughters in mine atmos-
pheres. These include: (1) removing radon and its radioactive
daughters from mine areas by air replacement, (2) inhibiting the
diffusion of radon into the air of the work areas from the sur-
rounding rock or from abandoned workings, (3) limiting the time
individuals can work in areas with an excessive air concentration
of radon-radon daughters (work force management), and (4)
reducing the concentration of radon daughters in the inspired air
from that prevalent in the mine atmosphere.
4.2 Ventilation of underground work areas is the most common
procedure. Natural draft ventilation is rarely adequate to provide
the needed rate of air supply. Therefore, mechanical movement of
the large volumes of air needed into or out of uranium mines is
now the general practice. Portable air ducts and auxiliary fans
are commonly used to conduct fresh air from its supply source
through passageways to deliver the air to work areas in all types
of underground mining. The incoming air dilutes and removes
air fouled by dust, drill exhaust, blasting fumes and gases, and
exhaust gases and heat from internal combustion engines. Venti-
lation is also necessary for comfort and health in underground
mines of all kinds. In uranium mines these same considerations
hold, but in addition ventilating air serves to remove radon and
radon daughters as well as the dust and noxious gases.
4.3 Currently the most practical means for removing radon and
its daughters from mines is to remove the contaminated air to the
outside and replace it with fresh air. Mine ventilation procedures
-------
1258 LEGAL COMPILATION—RADIATION
must take into account the size, number, and complexity of mine
workings and the level of radon and its daughter products present
within these workings. The concentration of radon and its daugh-
ters in mine atmospheres, if not diluted and carried away, can
build up to very high levels (i.e., hundreds of WL). Continuous
planned ventilation is much more effective than an intermittent
supply or exhaust of air, or solely relying on ventilation by natural
means.
4.4 The general considerations involved in ventilation control
include:
1. Fresh air supply should be channeled through the mine passageways in
such a manner that it would avoid mixing with contaminated air. The dis-
placed air should be promptly exhausted aboveground at a distance from the
air intake.
2. Old workings not needed for other purposes should be sealed off to inhibit
the release of radon into the work areas. This will also decrease the concen-
tration of radon daughters that can build up in the work areas.
3. Ventilation systems must be promptly altered or modified as development
proceeds.
4. Air velocities through mine areas where men work must be kept within
practical comfort limits.
[p. 33]
4.5 The volume of fresh air that can be supplied to underground
mine workings is subject to physical limitations on the air velocity
and pressure within the portable air ducts, and the velocity of the
displaced air through exhausting passageways. In regard to the
former, the power requirements to move a unit volume of air
through a duct of a given cross-sectional area are reported to in-
crease with the third power of the volume. The air velocity in
passageways directly affects the miners. (1) There are valid
objections to working in a high velocity air flow, especially when
the temperature is low. Underground work crews, particularly
those working continuously in passageways, object to being sub-
jected to uncomfortably high air flow rates, even though the air
temperature is maintained at a reasonable level.
4.6 Mines that are developed with foreknowledge of the ore
body extent and with engineering design for mining and ventila-
tion generally provide mechanical equipment to move air into and
out of the mine through multiple openings with the least possible
dilution or recirculation. A Bureau of Mines survey (2) has re-
lated radon daughter levels in underground uranium mines to the
various ventilation practices; that is, with fans blowing or ex-
hausting, with fresh air intake via the main mine entrance, or with
auxiliary ventilation holes and the total volume of fresh air sup-
plied. The results do not indicate any systematic differences
-------
GUIDELINES AND REPORTS 1259
among these procedures. Regardless of the system, however,
multiple exits are advantageous in shortening air retention time.
4.7 Prior to 1960 mine surveys were infrequent and in many
cases the results were not representative of the average concentra-
tion of radon daughters in the mine air. Since 1960 State agencies
and the major mining companies have conducted systematic moni-
toring in underground mines. Tables 4 and 5 (sec. II) show that
a significant reduction in the higher concentrations of radon
daughters in mine air has been achieved since 1960. (5) Although
the number of mines reporting average concentrations of 1 WL or
less is unchanged, average concentrations of 10 WL or more in
mines have been virtually eliminated. The percentage of mines
reporting average radon daughter concentrations in the range of
1 to 3 WL has increased. Public statements by mine association
and company officials in States having most of the underground
uranium mines suggest that the improvement is continuing. (4-6)
4.8 A meaningful comparison of mine ventilation cost from
mine to mine is difficult because the evolution of ventilation sys-
tems is intimately associated with and conditioned by individual
mine development. While it might be supposed that the cost of
ventilation in uranium mines would be greater than the cost for
ventilation in nonuranium mines, or that the cost of ventilation in
mines with a lower grade ore would be less than that for those with
a higher grade ore, this is not necessarily the case. Many other
cost-affecting features may be of greater significance than air
supply alone. These include such factors as depth below surface,
lateral extension of workings, arrangement of passageways, num-
ber and size of mine openings, and so forth. Because of the gen-
eral lack of specific information in this area, special analyses were
necessary to evaluate the cost-effect of ventilation rate. A number
of uranium mining companies have carried out and reported on
mine ventilation cost studies at the request of FRC staff (see tables
7 and 8). These estimates are intended to illustrate the general
magnitude of cost in a few selected mines and are not applicable
to the industry as a whole.
[p. 34]
4.9 One study concerns 11 of the larger underground mines that
produced more than 20 percent of the national total of uranium
ore. These mines have all been in operation for 6 to 7 years, and
it seems likely that they could continue in operation for several
more years if, after the end of the Government procurement pro-
gram in 1970, there is a continuing favorable market. These
mines are individually profitable enterprises and, in general, they
exemplify predevelopment planning for advantageous operation,
-------
1260 LEGAL COMPILATION—RADIATION
including the extra ventilation necessary for radon daughter con-
trol. They are similar in operation and depth from the surface.
The reported estimates are for the group as a whole.
4.10 To obtain a general estimate of an "exposure index" in
these 11 mines the following procedures were used. The concen-
trations of radon daughters in the ine air were determined by
taking 10-minute air samples at about monthly intervals at under-
ground work locations. The results of these determinations were
then correlated with the time of occupancy by various categories
of mine workers to give approximate time-weighted average ex-
posures. In this way, an "exposure index" related to the WL was
derived for each of the various work categories. These average
exposures were then weighted by the number of persons involved
in the respective categories to reach a "mine index" value repre-
senting the average exposure in the mine. The average mine
index value for the 11 mines was reported as about 2 WL in 1965.
4.11 Total costs are reported for the 11 mines collectively in
terms of "investment costs" and "annual operating costs." Based
on this cost experience covering 6 or 7 years, the mining com-
panies have also derived estimates of what these costs might be
for two hypothetical cases: (1) the investment cost and operation
expense necessary to provide the nominal ventilation that would
have been needed for these mines without considering radon con-
trol (the prevailing mine index value would have been about 10
WL), and (2) the investment and operating costs that would be
entailed in the further reduction of the prevailing mine index to
1.0 WL.
4.12 With these estimated costs, the extrapolated "10-year"
cost of mining for operation of mine indexes of 10 WL and 1 WL
were estimated. This extrapolation is intended to provide some
appreciation of the way total cost might vary under progressively
more stringent control requirements. These figures will differ
from the actual costs as follows:
1. Ore bodies that do not last for 10 years will have less than the extrapolated
10-year operating cost and more than the stated investment cost, since the in-
vestment would have to be repeated when a new ore body is opened.
2. Ore bodies that do allow operation for 10 years will require additional
investment and operating costs as the present operations are extended: These
costs cannot be estimated at the present time because the rate of new develop-
ment in particular locations cannot be predicted that far in advance. The re-
lationships are shown in table 7.
4.13 Another study concerns estimates for each of 3 mines
where conditions differ from the group of 11 mines as to geology,
depth, extent of workings, productive capacity, arrangement of
-------
GUIDELINES AND REPORTS 1261
passageways, number of openings, and so forth. Furthermore,
the economy of operations is so different that the data reported
for these 3 mines are not comparable to the group of 11 mines
discussed above, and perhaps not even comparable among them-
selves. Collectively, the annual production of uranium ore of the
three mines has been at a rate of about 2 percent of the national
total. This study presents ventilation investment costs and venti-
[p. 35]
lation operating costs over a 6-year period of continual improve-
ment effort together with current concentration values of radon
daughters in all mine areas of concern. It should be noted that air
concentration values are reported rather than a mine index. The
WL values reported in table 8 are averages for 1965 and represent
the present state of control development. The costs are then com-
pared with corresponding costs that would have been incurred if
the ventilation had been limited to that which would have been
needed in these mines without considering radon control. It has
been estimated that the radon daughter concentrations would then
have been in the range of 5 to 20 WL with this limited ventilation.
TABLE 7.—VENTILATION COST ESTIMATES—11 MINE STUDY
Investment Oper. cost Total cost
cost (10-yr. est.) (10 yrs )
Estimated mine
index WL
Millions of dollars
Past experience . 3 9
Estimated ventilation costs
without radon control 2.0
Additional cost radon control
from 10 WL to 2 WL 19
Estimated additional cost to
reduce from 2 WL to 1 WL 15
Total cost to control at 1 WL — 10 years
7.9
2.8
5.1
6.0
11.8
4.8
7.0
75
19.3
>2
'10
1
1 Composite mine index for 1965.
2 Estimate of what the composite mine index would be with normal ventilation practices.
-------
1262 LEGAL COMPILATION—RADIATION
TABLE 8.—VENTILATION COST ESTIMATES—3 MINE STUDY
Investment Open cost Total cost
cost (6-yr. est.) (6 yrs.)
Average
concentration
WL
Thousands of dollars
Past experience
Mine C
Total
Estimated for case of minimum
ventilation
Mine A
Mine B
Mine C
Total . . . .
361
321
75
757
63
66
06
135
120
85
50
255
21
18
04
43
481
406
125
1,012
84)
84
10 )
178
'1.4
'1.5
'1.5
25 to 20
' Average WL concentrations in 1965.
2 Estimate of what the average WL concentrations would be with normal ventilation practices.
[p. 36]
4.14 This study indicates that radon daughter control at 1.5
WL in these mines is being achieved at a total cost of about $834,-
000 over a 6-year period. The relation of ventilation cost to tons
of ore produced for the group of three mines is about 1.5 times the
corresponding relation in the 11 mine group because of differences
in size and other factors.
Inhibiting the Diffusion of Radon
4.15 Sealing off old workings not needed for other purposes is
common practice and is effective, but the use of various types of
coatings sprayed on the mine walls has proved to be ineffective in
reducing the diffusion of radon from the walls into the work areas.
Variations in barometric pressure have been shown to have an
inverse effect on the rate of radon emanation into mines and, there-
fore, on the concentration of radon and radon daughters in mine
air. (7) This suggests that an applied overexposure might be used
to advantage in some mines for reducing the release rate of radon
into mine air. Experiments designed to augment the normal at-
mospheric pressure in mines with an overpressure approximately
equal to the usual range of atmospheric pressure variation have
been performed. A pressure of 0.6 cm of mercury above normal
reduced the rate of radon release to mine air by a factor of about
5. It has also been reported that if the pressure can be lowered
in a nearby underground area-—removed perhaps a hundred feet
from the mine workings—the resulting flow of air into the rock
can induce a flow of radon away from the work spaces. The prac-
-------
GUIDELINES AND REPORTS 1263
tical value of these suggestions for mine application remains to
be demonstrated on an engineering scale. However, an electrical
analog system that permits analysis of the air flow in various
mine configurations at different simulated air pressures has been
developed. (8) Many of the primary factors can be investigated
cheaply without the necessity of large scale engineering ex-
perimentation.
Work Force Management
4.16 Although limiting a miner's occupancy time in relatively
high concentrations of radon or its daughter products has not been
a normal practice in uranium mining, this procedure has been used
in various activities of the nuclear industry when men routinely
work in radiation fields of varying intensities. Since the concen-
trations of radon daughters vary widely with location and with
time at a single location in a mine (from 1 WL in well ventilated
areas to several hundred WL in stagnant areas), it has been dif-
ficult to establish an accurate record of the time-weighted average
exposure for each worker. However, reasonable estimates of the
average values are possible, and improvement in the evaluations
can be expected in the future. Controlling a miner's exposure to
radon daughter concentrations by controlling the time he is al-
lowed to work in different atmospheres should generally be feasible
and not too restrictive, provided the radon daughter concentra-
tions are known and are not too high.
4.17 It is normal practice to control mine operations primarily
on the basis of estimated exposures to radon daughter concentra-
tions found in a working area at the time of sampling. The
Colorado Bureau of Mines, for example, assumes that in a small
mine with less than 15 men an individual miner will not spend
more than 50 percent of his time in areas with significant con-
centrations of radon daughters. In larger mines, where most of
the men stay underground for a full working shift, the men are
assigned an exposure value of 75 percent of the average value for
the mine.
[P. 37]
4.18 The basic philosophy of control in Colorado is that if the
maximum radon daughter concentration in working areas is kept
within acceptable limits, the individual worker will be adequately
protected without reference to mine averages or time-weighted
exposure calculations. New Mexico also limits maximum concen-
trations in mines, but places more emphasis on estimates of time-
weighted exposures in its control program. Both regulatory
-------
1264 LEGAL COMPILATION—RADIATION
programs are derived from recommendations made in 1960 by
Committee N-7 of the USA Standards Institute. Acceptable lim-
its, as recommended in the Institute's standard are:
(a) "If the 13-week weighted average exposure of the workers to radon
daughters, is less than the MFC, the conditions may be considered to be con-
trolled and no action is necessary.
(b) "If samples in any working area show a concentration of radon daugh-
ters exceeding the MFC, but less than three times this level, sufficient additional
measurements shall be taken to determine the worker's weighted average ex-
posure for 13 weeks.
(c) "If samples show a concentration of radon daughters more than 3 times
the MFC, but less than 10 times this value, corrective action shall be initiated.
(d) "If samples show a concentration of radon daughters greater than 10
times the MFC, immediate action shall be taken to reduce the worker's exposure
and correct the condition."
The MFC referred to in the Institute's recommendations is equiv-
alent to 1 WL of radon daughters in the mine atmosphere.
4.19 Integrating personnel exposures to a varying radiation
field by providing a personal dosimeter, such as a film badge, is
standard practice for controlling exposure to external sources in
the nuclear industry. A film badge capable of recording the alpha
particles emitted from nuclides in mine air has been developed
by the mining industry and its reliability is being tested. With
proper calibration, such a device may have utility as an integrating
dosimeter. The availability and use of a reliable integrating do-
simeter may permit more effective estimates of exposure than can
be achieved by calculation of time-weighted average exposures. In
addition, a detection system permitting continuous measurement
and remote readout of radon daughter concentrations in various
mine areas are under development.
4.20 The possibility that the quantities of the longer-lived lead
210 (RaD) or polonium 210 (RaF) in various body tissues could
serve as an index of the total quantities of radon and radon daugh-
ters taken in has been investigated. Concentrations of these
radionuclides in blood, excretion in urine, and deposition in hair,
teeth, and bone have been examined; however, present information
does not permit correlation of these quantities directly to lung dose.
Respirators
4.21 Reducing the concentrations of radon daughters in inspired
air, as compared to the concentrations in the mine air by the use
of respirators, is an obvious exposure control technique. Avail-
able estimates suggest that an ordinary surgeon's mask could give
a 2- to 5-fold reduction. More efficient filters with low impedance
might achieve a 5- to 100-fold reduction. Respirators would be
-------
GUIDELINES AND EEPORTS 1265
primarily effective for the partial removal of radon daughters.
Radon concentrations would not be affected. Therefore, respira-
[p. 38]
tors can be useful as ancillary devices to reduce exposure when the
radon daughter concentrations in the mine atmosphere are rela-
tively high. The primary problem with respirators now in use is
that it is very difficult to assure that they are used and that they
are worn properly, even if the design of the respirator is appro-
priate to mining operation.
4.22 The use of respirators or self-contained breathing devices
in United States uranium mines has been generally reserved for
emergencies or control of silica dust. It has been reported that
respirators that reduce the radon daughter products in inhaled air
are worn by uranium miners in some other countries. (9) Since
it is accepted that there should be more stringent control over the
internal radiation exposure received by uranium miners, the Coun-
cil staff strongly recommends that there be a concerted effort to
improve respiratory devices. It is imperative that they be reliable
and that they be acceptable to the miners. In most cases, under-
ground uranium miners wear additional equipment, such as the
hard hat, miners' lamp and battery (which may weigh up to 6
pounds), safety boots, and in some cases safety lines. In addition
to his regular equipment a miner may also have to carry many
different pieces of equipment and tools. His work sometimes re-
quires overhead work, barring of loose rock, crawling in cramped
spaces, and climbing ladders. If a respiratory device is to be im-
posed as an additional requirement it must not interfere with the
miner's vision or with his freedom of motion to such an extent that
it results in a net increase in his probability of incurring a serioas
accident. Furthermore, since oral communication is of major im-
portance in mines, any respirator design should take this into
account.
4.23 Use of respirators by miners should not deter mine man-
agement from providing adequate ventilation in their mines. Ven-
tilation remains the primary means by which radon daughter
concentrations can be controlled. If the basic principles of ven-
tilation engineering and design are closely followed, radon daugh-
ter concentrations in mines can be significantly reduced.
[p. 39]
EEFERENCES
(1) Coleman, R.D., et al. Radon and Radon Daughters Hazards in Mine At-
mospheres—Investigations on Supplemental Control. AIHI Quarterly, Dec.
1956.
-------
1266 LEGAL COMPILATION—RADIATION
(2) Report to Congress by Secretary of the Interior. Health and Safety of
Metal and Nonmetal Mines (submitted in response to PL 87-300, 75 Stat.
649), 1963.
(3) Colorado Bureau of Mines Annual Report, 1965.
(4) Romney, Miles P. Utah Mining Assoc. Testimony, p. 373, U.S. Congress,
Senate, Committee on Labor and Public Welfare. To establish a Federal
Metal and Nonmetallic Mine Safety Act; Hearings before Subcommittee on
Labor, 89th Congress, 2d session.
(5) Swent, L. W., Homestake Mining Co., N. Mex. Testimony, p. 408, U.S.
Congress, Senate, Committee on Labor and Public Welfare. To establish a
Federal Metal and Nonmetallic Mine Safety Act: Hearings before Subcom-
mittee on Labor, 89th Congress, 2d session.
(6) Beamer, R. W. Wyoming Mining Assoc. Testimony, p. 474, U.S. Con-
gress, Senate, Committee on Labor and Public Welfare. To establish a Fed-
eral Metal and Nonmetallic Mine Safety Act: Hearings before Subcommittee
on Labor, 89th Congress, 2d session.
(7) Schroeder, G. L., Evans, R. D., and Kramer, H. W. Effect of Applied
Pressure on Radon Characteristics of an Underground Mine Environment
Trans. Society of Mining Engineers, March 1966.
(8) MIT Annual Progress Report (1966), MIT-952-3. Radium and Meso-
thorium Poisoning and Dosimetry and Instrumentation Techniques in Ap-
plied Radioactivity.
(9) Proc. IAEA Symposium on Radiological Health and Safety in Mining and
Milling of Nuclear Materials, Vienna, p. 32, 1964.
[p. 41]
SECTION V
SUMMARY AND RECOMMENDATIONS
5.1 To provide a Federal policy on human radiation exposure,
the Federal Radiation Council was formed in 1959 (Public Law
86-373) to "... advise the President with respect to radiation
matters, directly or indirectly affecting health, including guidance
for all Federal agencies in the formulation of radiation standards
and in the establishment and execution of programs of cooperation
with States." The present report fulfills this responsibility with
regard to a Federal policy relating to the protection of under-
ground uranium miners against deleterious health effects resulting
from the inhalation of the radioactive daughters of radon 222.
Although primary emphasis has been placed on underground ura-
nium mining, the guidance contained in this report may be applied,
as necessary, to any type of mine where similar concentrations of
radon daughter products may be found.
5.2 This report emphasizes the radiation hazard associated with
the inhalation of radon daughters as they occur in the air of under-
ground uranium mines. Although other sources of radiation expo-
sure occur in connection with underground mining, and potential
radiation effects are not necessarily confined to the respiratory
-------
GUIDELINES AND EEPORTS 1267
system, they are considered of secondary importance as compared
to the possible effects resulting from the inhalation of radon
daughters.
5.3 In prior reports the Federal Radiation Council has ex-
pressed the philosophy that guidance for radiation protection in-
volves achieving a balance between the risk of radiation-induced
injury and the benefits derived from the practice causing the expo-
sure to radiation. An implicit part of such a balance is a necessity
for considering the relation between the difficulties involved in
reducing the radiation exposure by a given amount and the risk
that might be associated with that amount of exposure.
Evidence of Radiation Hazards in Underground Uranium Mines
5.4 Available information on the radiological factors involved
in the underground mining of uranium ore has been carefully ex-
amined. The findings of immediate interest for establishing radi-
ation protection guidance are:
1. It has been observed that underground uranium miners have a higher
incidence of lung cancer than is found in the male population in the same geo-
graphic area. Continued exposure to the radioactive decay products of the
naturally occurring gas radon 222 has been implicated as an important cause
of this increased incidence. The decay products of radon 222 (radon daugh-
ters) of interest are: polonium 218, lead 214, bismuth 214, and polonium 214.
For purposes of this report, the radiation dose from radon itself is not con-
sidered.
2. The principal radiation hazard is associated with the inhalation of mine
air containing radionuclides that irradiate lung tissue nonuniformly. The
most serious result is the development of lung cancer, which generally does
[p. 43]
not appear for 10 to 20 years after the individual started uranium mining.
3. In most domestic underground uranium mines the measurement of radon
daughter concentration is obtained by using a specific field method. The re-
sults are then compared to the "Working Level" (WL), a unit defined as any
combination of radon daughters in 1 liter of air that will result in the ultimate
emission of 1.3 x 10s MeV of potential alpha energy. The concentration of
radon daughters in air of unventilated underground uranium mines ranges
from a fraction of a WL to several hundred WL. Exposure to radon daugh-
ters over a period of time may be expressed in terms of cumulative "Working
Level Months" (WLM). Inhalation of air containing a radon daughter con-
centration of 1 WL for 170 working hours results in an exposure of 1 WLM.
4. Observations on United States uranium miners who started underground
mining before July 1955 clearly demonstrate that an association exists between
exposure to radon daughters and a higher than expected incidence of lung
cancer when the cumulative exposures are more than about 1,000 WLM. The
degree of risk at lower levels of cumulative exposure cannot be determined
from currently available epidemiological data. As discussed in paragraph
3.14, the data do not suggest or exclude the existence of a threshold. It is
prudent, however, to assume that some degree of risk exists at any level of ex-
-------
1268 LEGAL COMPILATION—-RADIATION
posure, even though possible effects may not now be evident at the lower levels
of cumulative exposure.
5. The highest incidence of lung cancer is now occurring in the group of
miners: (1) who worked in mines in which the average concentration of radon
daughters was usually higher than 10 WL; (2) whose total cumulative ex-
posures were estimated to range upward from about 1,000 WLM; (3) who
started mining uranium ore more than 10 years ago, and (4) who were mod-
erate to heavy cigarette smokers. These observations suggest that additional
cases of lung cancer can be expected to develop in the study group.
Factors Related to the Evaluation of Benefit and Control
Capabilities
5.5 Available information on benefits to be derived from the
mining of uranium ores, difficulties encountered in reducing radon
daughter concentrations from previous levels to current levels, and
the additional difficulties that can be anticipated if further reduc-
tions in radon daughter concentrations are required has also been
reviewed. The findings of immediate interest to the derivation of
guidance for radiation protection in uranium mining are as
follows:
1. Uranium is currently the basic fuel needed for the development of nuclear
energy, and all projections point to an increasingly important role for nuclear
energy in meeting national electric power requirements.
2. Uranium mining is an important economic asset to the States in which the
ore is mined. In addition to the value of the ore, mining provides important
opportunities for employment. It is estimated that the work force will vary
between 2,000 and 5,000 men in the next decade.
3. A significant reduction in the concentration of radon daughters in the air
of underground mines has been achieved by the industry since 1960. Estimates
of probable exposures of 2,177 miners in a five-State area during the third
quarter of 1966 indicate that about 31 percent of miners were exposed to levels
of 1 WL or less; 55 percent were exposed in the range of 1-3 WL; and about
14 percent were exposed to levels higher than 3 WL.
[p. 44]
4. Ventilation with fresh air is presently considered the most feasible tech-
nique for controlling the concentrations of radon daughters in mine air. The
highest concentrations are usually found in the stope areas where some work
must be done before ventilation can be brought directly to the miner's working
area. This suggests that there are practical limits to the degree by which
radon daughter concentrations in mine air can be controlled by ventilation
alone. Available information suggests that it may be physically impossible
to maintain radon daughter concentration in all parts of the mine to as low as
1 WL at all times.
5. Research studies have been made on possible procedures that might be
used to block the diffusion of radon from rock into mine air. Positive pressure
ventilation can be useful if the rock is porous enough to permit air to flow into
it. Coating the rock surface might be useful if it is capable of blocking the
diffusion of radon.
6. The effectiveness, feasibility, and safety of various types of auxiliary
-------
GUIDELINES AND REPORTS 1269
respiratory protective equipment, as they might be used in underground ura-
nium mining, deserve the most thorough study.
7. It is common practice to limit the highest radon daughter concentrations
in which normal mining operations are allowed without determining the ra-
diation exposure at lower concentrations. This procedure makes it possible to
estimate the maximum exposure rate, but does not provide the information
necessary for estimating a true average exposure, and hence the radiation risk
for any one individual or group.
Guidance for Radiation Protection in Underground Mines
5.6 On the basis of the preceding findings, the Federal Radiation
Council has concluded that radon and its radioactive daughter
products occur in sufficient concentrations in underground ura-
nium mines to require actions to control the potential radiation
exposure associated with working in such environments. Al-
though primary emphasis has been placed on underground ura-
nium mining, the guidance contained in this report may be applied,
as necessary, to any type of mine where similar concentrations of
radon daughter products may be found.
5.7 The Council has considered: (1) the apparent relationship
between cumulative exposure to radon daughters and the risk of
subsequent development of lung cancer as shown by presently
available epidemiological data; (2) the range of annual exposures
received by various categories of miners now engaged in uranium
mining; (3) the technological problems involved in achieving con-
trol to various levels of annual exposure, and the ability of present
technology as practiced by the industry to reduce radon concentra-
tions to different levels; (4) improvements that might be intro-
duced by application of a more advanced technology, and the
length of time such improvements might take; and (5) the mag-
nitude of the radiation risk in the light of the other risks that are
faced in underground uranium mining, and the impact the Coun-
cil's recommendations might have on efforts to reduce these risks
simultaneously.
5.8 The selection of the proposed standard for the control of
radon daughters in underground mine air must necessarily involve
a judgment based on all relevant information. In selecting the
standards the Council has also considered: (1) the possible magni-
tude of the cumulative radiation exposure that individuals might
receive under the practical application of the proposed standard;
(2) the range of individual risk that might result; (3) the prac-
[p. 45]
tical difficulties and feasibility of reducing exposures; (4) the
change in individual risk that could be associated with such
reduced exposures; and (5) various control standards used by
-------
1270 LEGAL COMPILATION—RADIATION
different countries for control of radon and radon daughter con-
centrations in underground uranium mines.
5.9 On the basis of the information presented in the preceding
sections, the following guidance is recommended:
1. Occupational exposure to radon daughters in underground uranium mines
be controlled so that no individual miner will receive an exposure of more than
6 WLM in any consecutive 3-month period and no more than 12 WLM in any
consecutive 12-month period. Actual exposures should be kept as far below
these values as practicable.
2. Areas in underground uranium mines, whether normally or occasionally
occupied, be monitored for the concentration of radon daughters in the mine
air. The location and frequency of taking samples should be determined in
relation to compliance with recommendation 1.
3. Appropriate records of the exposure from radon daughters in the mine
air received by individuals working in uranium mines be established and main-
tained.
5.10 The Federal Radiation Council recognizes that current
mining conditions are much better than those prevailing 10 years
ago. However, it also considers that more improvement is needed
to provide proper control of exposure to radon daughters. Steps
to make improvements should be initiated immediately and made
operational as soon as possible.
Research and Development Needs
5.11 The Federal Radiation Council recognizes that present
regulatory procedures and the presently used technology are not
adequate to insure compliance with the foregoing recommenda-
tions. The development of the appropriate technology and the
modification of existing regulatory procedures needs to be sup-
ported by an applied research and development program. The
general areas deserving attention include: (1) the development of
the technology directed to the control and more reliable estimate
of individual exposures to radon daughters; (2) registration and
compilation of individual exposure records; (3) causal relation-
ships between varying exposures to radon daughters and subse-
quent development of disability; and (4) improvement of mining
practices. In addition, continued attention needs to be given to the
development of adequate compensation procedures and the pro-
vision of educational opportunity and training programs wherever
needed.
5.12 The technology concerned with the control and estimate of
individual exposure to radon daughters include: (1) the develop-
ment of more sensitive and more rugged equipment for the meas-
urement of radon daughter concentrations in mine air; (2) the
development of continuous air monitoring equipment; (3) the
-------
GUIDELINES AND KEPORTS 1271
development of devices permitting measurement of integrated ex-
posures (personnel dosimetry); (4) the development and testing
of low impedance respiratory protective devices; and (5) a more
precise definition of the composition of the mine atmospheres,
including (a) a measurement of radon 222 and each of its first
three daughters separately in representative mine air, (b) the
distribution of the three daughters between ions, nuclei, and va-
rious larger particle sizes, and (c) the conditions under which
these may be altered by varying modes of ventilation, or by various
designs of respirators.
[p. 46]
5.13 The practical determination of what is needed to imple-
ment the recommendations should take cognizance of the follow-
ing: (1) data needed to indicate compliance with recommendation
1; (2) an evidentiary record needed to support or deny claims for
occupational disability; (3) studies to evaluate possible causal re-
lationships between exposure to radon daughters and the incidence
of lung cancer at the lower cumulative exposure levels; and (4)
development of a basis for estimating cumulative occupational
exposure that the average miner might receive in the future under
this guidance.
5.14 In regard to causal relationships, epidemiological studies
should be continued on uranium miners and expanded to include
other miners who could serve as appropriate comparison groups.
Such studies should include, with proper categorization, low, inter-
mediate, and high radon-—radon daughter exposure groups as well
as a health history followup.
5.15 The development of improved mining practices should
place the emphasis on mine-planning as it relates to ventilation,
removal of radon daughters from underground mine air, and re-
duction of radon emission from the rock into the mine. This
program is primarily directed to the control of the mine air
environment.
[P. 47]
REFERENCES
(1) Lea, D. E. Action of Radiations on Living Cells (second edition). Cam-
bridge Press, 1955.
(2) Jacobi, W. The Dose to the Human Respiratory Tract by Inhalation of
Short-lived Radon 222 Decay Products. Proc. Hanford Symposium Inhaled
Radioactive Particles and Gases. Health Physics, Vol. 10, p. 1163, 1964.
(3) Evans, R. D., and Goodman, C. Determination of the Thoron Content of
Air and Its Bearing on Lung Cancer Hazards in Industry. J. Ind. Hyg. and
Toxicol., Vol. 22, p. 89,1940.
-------
1272 LEGAL COMPILATION—RADIATION
(4) Stewart, C. G., and Simpson, S. D. The Hazards of Inhaling Radon 222
and Its Short-lived Daughters: A Consideration of Proposed Maximum Con-
centrations in Air. IAEA Proc. Symposium Radiological Health and Safety
in Mining and Milling Nuclear Materials, Vienna, Vol. I, p. 333, 1964.
(5) Failla, G. Tolerance Concentration of Radioactive Gases in Air. AECD-
2362, Nov. 1942.
(6) Mitchell, J. S. Memorandum on Some Aspects of the Biological Action
of Radiations, Special Reference to Tolerance Problems. Montreal Lab. Re-
port HI-17, 1945.
(7) Bale, W. F. Hazards Associated With Radon and Thoron. Unpublished
memo., 1951.
(8) Shapiro, J., and Bale, W. F. A Partial Evaluation of the Hazard from
Radon and Its Degradation Products. Univ. Rochester Atomic Energy
Project Report, UR-242, p. 6, 1953.
(9) Shapiro, J. An Evaluation of the Pulmonary Radiation Dosage from
Radon and Its Daughter Products. Univ. Rochester Atomic Energy Pro-
ject, UR-298, 1954.
(10) Bale, W. F., and Shapiro, J. V. Radiation Dosage to Lungs from Radon
and Its Daughter Products. Proc. UN International Conf. on Peaceful Uses
of Atomic Energy, Vol. 13, p. 233, 1955.
(11) Shapiro. J. Radiation Dosage From Breathing Radon and Its Daugh-
ter Products. AMA Arch. Ind. Health, Vol. 14, p. 169, 1956.
(12) Chamberlain, A. C., and Dyson, E. D. The Dose to the Trachea and
Bronchi From the Decay Products of Radon and Thoron. Brit. J. Radiol.,
Vol. 29, p. 317, 1956.
(13) Gormley, P. G., and Kennedy, M. Diffusion From a Stream Flowing
Through a Cylindrical Tube. Proc. Royal Irish Acad., Vol. 52, p. 163, 1948.
(14) Triparite Conf. on Permissible Doses, March-April 1953. Arden House,
Harriman, N.Y.
(15) Morgan, K. Z. Maximum Permissible Concentration of Radon in the Air.
Unpub. memo., October 27, 1954.
(16) ICRP Pub. 2: Report of Committee II on Permissible Dose for Internal
Radiation. Pergamon Press, 1959.
(17) ICRP Pub. 6 (as amended 1959 and revised 1962). Pergamon Press,
1964.
(18) ICRP Task Group on Lu.ng Dynamics: Deposition and Retention Models
for Internal Dosimetry of the Human Respiratory Tract. Health Physics
Vol. 12, p. 173, 1966.
(19) Altshuler, B., Nelson, N., and Kuschner, M. Estimation of the Lung
Tissue Dose From Inhalation of Radon and Daughters. Proc. Hanford
Symposium Inhaled Radioactive Particles and Gases. Health Physics, Vol.
10, p. 1137, 1964.
(20) Tsivoglou, E. C., Ayer, H. E., and Holaday, D. A. Occurrence of Non-
equilibrium Atmospheric Mixtures of Radon and Its Daughters. Nucleonics,
Vol. 11, p. 40,1953.
(21) HASL-91: Experimental Environmental Study of AEC Leased Uranium
Mines. Health and Safety Laboratory, USAEC, New York, 1960.
[p. 59]
(22) Landahl, H. D. Particle Removal by the Respiratory System—Note on
the Removal of Airborne Particulates by the Human Respiratory Tract with
Particular Reference to the Role of Diffusion. Bull. Math. Biophys., Vol.
25, p. 29,1963.
-------
GUIDELINES AND REPORTS 1273
(23) Engel, S. Lung Structure. C. C. Thomas, Springfield, 111., 1962.
(24) Haque, A. K. M. M., and Collinson, A. J. L. Radiation Dose to the Res-
piratory System Due to Radon and Its Daughter Products. Health Physics,
Vol. 13, p. 431, May 1967.
(25) Weibel, E. R., Morphometry of the Human Lung. Academic Press, Inc.,
New York, 1963.
(26) USPHS Pub. 494 (1957). Control of Radon and Daughters in Uranium
Mines and Calculation on Biologic Effects.
(27) Gross, P. The Processes Involved in the Biologic Aspects of Pulmonary
Deposition, Clearance, and Retention of Insoluble Aerosols. Proc. Hanford
Symposium Inhaled Radioactive Particles and Gases. Health Physics, Vol.
10, p. 995, 1964.
(28) Hilding, A. C. On Cigarette Smoking, Bronchial Carcinoma and Ciliary
Action. III. Accumulation of Cigarette Tar Upon Artificially Produced
Deciliated Islands in Respiratory Epithelium. Ann. Otol., Vol. 65, p. 116,
1956.
[p. 60]
4.1(h)(l) RADIATION PROTECTION GUIDANCE FOR
FEDERAL AGENCIES (MEMORANDUM TO THE
PRESIDENT), FEDERAL RADIATION COUNCIL
August 1,1967,32 Fed. Reg. 11183 (1967)
MEMORANDUM FOR THE PRESIDENT
JULY 21,1967.
Pursuant to Executive Order 10831 and Public Law 86-373 the
Federal Radiation Council transmits to you its findings and recom-
mendations for the guidance of Federal agencies in the conduct of
their radiation protection activities as they apply to the under-
ground mining of uranium ore.
In prior memorandums and reports the Council has expressed
the philosophy that guidance for radiation protection involves
achieving a balance between the risk of radiation-induced injury
and the benefits derived from the practice causing the exposure to
radiation. An implicit part of such a balance is a necessity for
considering the relation between the difficulties involved in reduc-
ing radiation exposures by a given amount and the risk that might
be associated with that amount of exposure.
Assessment of radiation hazards in underground uranium mines.
The Council has reviewed available information on the radiological
factors involved in the underground mining of uranium ore. The
findings of immediate interest for establishing radiation protection
guidance for this activity are:
1. It has been observed that underground uranium miners have a higher
incidence of lung cancer than is found in the male population in the same
geographic area. Continued exposure to the radioactive decay products of the
-------
1274 LEGAL COMPILATION—RADIATION
naturally occurring gas radon 222 has been implicated as an important cause
of this increased incidence. The decay products of radon 222 (radon daugh-
ters) of interest are: Polonium 218, lead 214, bismuth 214, and polonium 214.
For purposes of this memorandum, the radiation dose from radon itself is not
considered.
2. The principal radiation hazard is associated with the inhalation of mine
air containing radionuclides that irradiate lung tissue nonuniformly. The most
serious result is the development of lung cancer, which generally does not
appear for 10 to 20 years after the individual started uranium mining.
3. In most domestic underground uranium mines the measurement of radon
daughter concentration is obtained by using a specific field method. The results
are then compared to the "Working Level" (WL), a unit which is defined as
any combination of radon daughters in one liter of air that will result in the
ultimate emission of 1.3 X 10s MeV of potential alpha energy. The concentra-
tion of radon daughters in the air of unventilated underground uranium mines
ranges from a fraction of a WL to several hundred WL. Exposure to radon
daughters over a period of time may be expressed in terms of cumulative
"Working Level Months" (WLM). Inhalation of air containing a radon
daughter concentration of 1 WL for 170 working hours results in an exposure
of 1 WLM.
4. Observations on U.S. uranium miners who started underground mining
before 1955 clearly demonstrate that an association exists between exposure
to radon daughters and a higher than expected incidence of lung cancer when
the cumulative exposures are more than about 1,000 WLM. The degree of risk
at lower levels of cumulative exposure cannot be determined from currently
available epidemiological data. It is prudent to assume that some degree of
risk exists at any level of exposure, even though possible effects may not now
be evident at the lower levels of cumulative exposure.
5. The highest incidence of lung cancer is occurring now in the group of
miners: (1) Who worked in mines in which the average concentration of radon
daughters was usually higher than 10 WL; (2) whose total cumulative ex-
posures were estimated to range upward from about a thousand WLM; (3)
who started mining uranium ore more than 10 years ago; and (4) who were
moderate to heavy cigarette smokers. These observations suggest that addi-
tional cases of lung cancer can be expected to develop, even in individuals who
may have already left underground mining.
Factors related to the evaluation of benefit or control capability.
The Council has also reviewed available information on the benefits
to be derived from the mining of uranium ores; on the difficulties
that have been encountered in reducing radon daughter concentra-
tions from previous levels to current levels, and the additional
difficulties that can be anticipated if further reductions are re-
quired. The findings of immediate interest to the derivation of
guidance for radiation protection in uranium mining are as
follows:
1. Uranium is currently the basic fuel needed for the development of nuclear
energy, and all projections point to an increasingly important role for nuclear
energy in meeting national electric power requirements.
2. Uranium mining is an important economic asset to the states in which
the ore is mined. In addition to the value of the ore, mining provides important
-------
GUIDELINES AND REPORTS 1275
opportunities for employment. It is estimated that the work-force will vary
between 2,000-5,000 men in the next decade.
3. A significant reduction in the concentrations of radon daughters in the
air of underground mines has been achieved by the industry since 1960. Esti-
mates of probable exposures of 2,177 miners in a five-state area during the
third quarter of 1966 indicate that about 31 percent of the miners were exposed
to levels of 1 WL or less; 55 percent were being exposed to the range of 1-3
WL; and about 14 percent were exposed to levels higher than 3 WL.
4. Ventilation with fresh air is presently considered the most feasible tech-
nique for controlling the concentrations of radon daughters in mine air. The
highest concentrations are usually found in the stope areas where some work
must be done before ventilation can be brought directly to the miner's working
area. This suggests that there are practical limits to the degree by which
radon daughter concentrations in mine air can be controlled by ventilation
alone. Information made available to the Council indicates that it will probably
be physically impossible to maintain the radon daughter concentration in all
parts of the mines to as low as 1 WL at all times.
5. Research studies have been made on possible procedures that might be
used to block the diffusion of radon from the rock into mine air. The use of
positive pressure ventilation can be useful if the rock is porous enough to
permit air to flow into it. Coating the rock surface might be useful if it is
capable of blocking the diffusion of radon.
6. The effectiveness, feasibility, and safety of various types of auxiliary
respiratory protection equipment, as they might be used in underground
uranium mining, deserve the most thorough study.
7. It is common practice to limit the highest radon daughter concentrations
in which normal mining operations are allowed without determining the radia-
tion exposure at lower concentrations. This procedure makes it possible to
estimate the maximum exposure rate, but does not provide the information
necessary for estimating the true average exposure, and hence radiation risk
for any one individual or group.
Guidance for radiation protection in underground mining. On
the basis of the preceding findings, the Federal Radiation Council
has concluded that radon and its radioactive daughter products
occur in sufficient concentrations in underground uranium mines
to require actions to control the potential radiation exposure as-
sociated with working in such environments. Although primary
emphasis has been placed on underground uranium mining, the
guidance contained in this memorandum may be applied, as neces-
sary, to any type of mine where similar concentrations of radon
daughter products may be found.
In reaching its recommendations the Council has considered:
(1) The apparent relationship between cumulative exposure to
radon daughters and the risk of subsequent development of lung
cancer as shown by presently available epidemiological data; (2)
the range of annual exposures received by various categories of
miners now engaged in uranium mining; (3) the technological
problems involved in achieving control to various levels of annual
-------
1276 LEGAL COMPILATION—RADIATION
exposure, and the ability of present technology as practiced by the
industry to reduce radon concentrations to different levels; (4)
improvements that might be introduced by the application of a
more advanced technology, and the length of time such improve-
ments might take; and (5) the magnitude of the radiation risk in
the light of the other risks that are faced in underground mining,
and the impact the Council's recommendations might have on
efforts to reduce these risks simultaneously. In balancing these
considerations, it is recommended that:
1. Occupational exposure to radon daughters in underground uranium mines
be controlled so that no individual miner will receive an exposure of more
than six WLM in any consecutive 3-month period and no more than 12 WLM
in any consecutive 12-month period. Actual exposures should be kept as far
below these values as practicable.
2. Areas in underground uranium mines, whether normally or occasionally
occupied, be monitored for the concentration of radon daughters in mine air.
The location and frequency of taking samples should be determined in relation
to compliance with recommendation number 1.
3. Appropriate records of the exposure from radon daughters in the mine
air received by individuals working in uranium mines be established and
maintained.
The Federal Radiation Council recognizes that current mining
conditions are much better than those prevailing 10 years ago.
However, it also considers that more improvement is needed to
provide proper control of exposure to radon daughters. Steps to
make improvements should be initiated immediately and made
operational as soon as possible.
The practical determination of what is needed to implement the
recommendations should take cognizance of the following reasons
for making the necessary measurements and the compilation of
appropriate records: (1) Data needed to indicate compliance with
recommendation number 1, (2) the evidentiary record needed to
support or deny claims for occupational disability, (3) permit
future evaluation of possible causal relationships between exposure
to radon daughters and respiratory cancer at the lower cumulative
exposure levels, and (4) to develop a basis for estimating the
cumulative occupational exposure that the average miner might
receive in the future under this guidance.
The control of an airborne hazardous agent, such as radon and
its radioactive daughters, can be achieved either by controlling the
environment by appropriate ventilation or by providing auxiliary
procedures and equipment to offset exposure from the environ-
ment. Examples of such procedures are limiting the time in-
dividuals are allowed to work in the environment, or the use of
-------
GUIDELINES AND REPORTS 1277
respiratory protection devices capable of removing most of the
radon daughters present in the mine air.
These procedures should also be accompanied by an educational
program under the direction of mine management so that the miner
may be advised on the necessity for taking these precautionary
measures and to emphasize the miner's responsibility in reducing
his exposure to radioactive materials.
The Council urges the appropriate Federal agencies to cooperate
fully with the states and the uranium mining industry in provid-
ing realistic and coordinated programs in the following areas:
1. The development of technology directed to the control and more reliable
estimates of individual exposures to radon daughters.
2. The registration and compilation of individual exposure records.
3. Research on causal relationships involving varying exposure to radon
daughters and the subsequent development of disability.
4. Research and development directed toward better mining practices.
5. Development of adequate compensation procedures.
6. Educational opportunities and training programs wherever needed.
In approximately 1 year the Federal Radiation Council intends
to review its guidance for radiation protection in uranium mining.
At that time, if it is indicated, the recommendations in this mem-
orandum will be changed accordingly.
If the foregoing recommendations are approved by you for the
guidance of Federal agencies in the conduct of their radiation
protection activities, it is further recommended that this mem-
orandum be published in the FEDERAL REGISTER.
JOHN W. GARDNER,
Chairman.
Recommendations 1, 2, and 3 in the preceding memorandum are
approved for the guidance of Federal agencies, and the memoran-
dum shall be published in the FEDERAL REGISTER.
LYNDON B. JOHNSON.
4.2 SELECTED REPORTS:
4.2a PATHOLOGICAL EFFECTS OF THYROID IRRADIATION,
FEDERAL RADIATION COUNCIL, REVISED REPORT-
DECEMBER 1966
FOREWORD
A special subcommittee of the National Academy of Sciences-
National Research Council Advisory Committee to the Federal
Radiation Council met on September 19, 1966, to consider and
update the July 1962 report on Pathological Effects of Thyroid
Irradiation. The conclusions reached at this meeting, and by sub-
-------
1278 LEGAL COMPILATION—RADIATION
sequent correspondence, are presented in this report and are based
on information available through November 1966. The members
of the subcommittee acted as individuals, not as representatives of
their organizations.
Shields Warren, Chairman
Subcommittee on Effects of
Radiation on the Thyroid Gland
Howard L. Andrews Cyril L. Comar
Victor P. Bond Louis H. Hempelmann
Leo K. Bustad Albert W. Hilberg
This report was approved by the Advisory Committee to the
Federal Radiation Council at its meeting on December 10, 1966.
Cyril L. Comar, Chairman
Advisory Committee
Seymour Abrahamson Brian MacMahon
Howard L. Andrews Joseph E. Rail
Victor P. Bond William L. Russell
George W. Casarett Eugene L. Saenger
Louis H. Hempelmann Shields Warren
Samuel P. Hicks
[p. iii]
PATHOLOGICAL EFFECTS OF THYROID IRRADIATION
INTRODUCTION
The constituent groups of the National Academy of Sciences—
National Research Council Committees on the Biological Effects of
Atomic Radiation (now disbanded) had met periodically since
their formation in 1955 to consider various aspects of the general
problem. In 1961 a report on Internal Radioactive Emitters l was
issued, which included a discussion of the effects of iodine 131 on
the human thyroid gland. A special report on the Pathological
Effects of Thyroid Irradiation was issued by the Federal Radiation
Council in July, 1962.- Enough new evidence on the effects of
1 Publication No. 883, "Internal Emitters," 1961, of the National Academy of Sciences-National
Research Council.
- "Pathological Effects of Thyroid Irradiation," Federal Radiation Council, Washington, D.C.,
July 1962.
-------
GUIDELINES AND REPORTS 1279
irradiation of the thyroid has come to hand to warrant considera-
tion by the Advisory Committee to the Federal Radiation Council;
for this purpose, there was established a Subcommittee on the Ef-
fects of Radiation on the Thyroid Gland augmented by consultants
with special knowledge of the field. Although parts of the avail-
able data are unpublished and incomplete, some investigations
have reached a point where certain conclusions can be safely
drawn.
Some of these data come from long-term studies on the effects
of medically indicated irradiations involving the thyroid gland of
man. Other data come from long-term animal experiments using
either iodine 131 or X-rays as the source of radiation.
The human thyroid gland may be exposed to radiation from a
variety of sources. Medical and dental requirements can lead to
an X-ray exposure, either from a direct beam or as scatter from
the irradiation of adjacent areas. Radioactive iodine may be ad-
ministered for either diagnostic or therapeutic purposes. Sub-
stantial quantities of iodine 131 are produced in nuclear fission and
may be released to the environment, principally during nuclear
testing in the atmosphere or from some types of reactor accidents.
The most important radionuclide of iodine, iodine 131, has a
very short half-life of 8 days which limits the quantities that can
gain entrance into the body. Fallout from nuclear detonations or
from a nuclear reactor accident may deposit iodine 131, as well as
other radionuclides, including very short-lived radioiodines, on
vegetation and in water supplies downwind from the point of re-
lease. The absorption of iodine 131 by inhalation will be un-
important except possibly in fallout intensities, which are intoler-
able for other reasons or immediately following a reactor accident.
Direct absorption through the skin has not been demonstrated to
be an important mode of entry of radioiodines in fallout. In
sources of drinking water for major urban populations the relay
between rainfall and consumption usually assures decay of iodine
131 to an insignificant level. In addition, dilution and other fac-
tors are effective in reducing the fallout concentration.
Fresh food becomes, then, the main source of iodine 131 from
the environment. For most foods the time delay between harvest
and consumption is sufficient to reduce iodine 131 to an insignifi-
cant level. This is not generally the case with fresh milk for which
the time between production and consumption averages about 3
days in the United States. There is some evidence suggesting that
consumption of some locally grown vegetables and produce, even
after washing and normal home preparation, could conceivably
contribute to the diet amounts of the order of those from fresh
-------
1280 LEGAL COMPILATION—RADIATION
milk.3 However, there is no question that fresh milk is by far the
major contributor of iodine 131 to the United States population
as a whole.
[p. 1]
Relatively little information is available on the consumption of
fresh cow's milk by people in various age groups. The most de-
tailed study now available was completed in 1962 and presents per
capita consumption by age and sex. '• •"• During the first few months
of life the intake of fresh cow's milk may be zero for infants who
are breast-fed or given formulas based on processed products.
From the survey study the average for children under one year of
age was about 0.5 liter per day which was maintained until late
teenage, after which a gradual decline occurred. For adult males
and females in the population-at-large averages were 0.35 and 0.25
liters per day respectively. The range extended from persons
consuming no milk to a group comprising 1 to 10 percent who con-
sumed more than 1 liter per day. Large individual differences
were found at all ages.
The thyroid gland is unique in its relation to the metabolism of
iodine in either stable or radioactive form. Weighing only about
1 to 2 grams at birth, and 15 to 20 grams in the adult, this gland
has a high affinity for iodine. A normal thyroid will absorb and
retain 15 to 30 percent of a small quantity of ingested iodine. The
exact amount retained will depend, among other things, upon the
amount of stable iodine ingested during the preceding few days
or weeks. Iodine not absorbed by the thyroid will be rapidly
excreted, primarily in the urine. Thus, in a short time after a
single intake, the gland will contain the highest concentration of
the iodine remaining in the body. Because of its great avidity for
radioiodine the thyroid will receive the largest radiation dose,
particularly if the form is iodine 131.
The radiation dose delivered to other tissues will be, at most, a
few percent of that received by the thyroid gland. A concentration
of 1 microcurie of iodine 131 per gram of thyroid tissue will pro-
duce a time-integrated dose of about 113 rads," ranging from 90
3 R. H. Wasserman, F. W. Lengemann, J. C. Thompson, Jr., and C. L. Comar. "The Transfer of
Fallout Radionuclides from Diet to Man," Chaptei 9, in Radioactive Fallout, Soils, Plants, Foods,
Man edited by E. B. Fowler, Elsevier, 1965.
4 Bureau of the Census, Department of Commerce and Division of Radiological Health, Public
Health Service, "National Food Consumption Survey: Fresh Whole Milk Consumption in the
United States." Radiological Health Data 4:15, No. 1, 1963.
:> Bureau of the Census, Department of Commerce and Division of Radiological Health, Public
Health Service, "Consumption of Selected Food Items in U.S. Households." Radiological Health
Data 4:124, No. 3, 1963.
6 Report of the International Commission on Radiological Units and Measurements (ICRU),
1959. National Bureau of Standards Handbook 78, January 16, 1961, Washington, D.C.
-------
GUIDELINES AND REPORTS 1281
to 130 rads.7 About 10 percent of this dose will be received in the
first 24 hours, probably over 25 percent in the first 2 days.
When the thyroid is included in the beam from an external radi-
ation source, such as an X-ray tube, a considerable amount of sur-
rounding tissue will necessarily receive doses equal to or even
greater than that received by the gland itself.
Differences in growth rate and histology of the thyroid from
birth through early childhood have led some to believe that the
infant thyroid is more vulnerable than that of the adult to injury
from ionizing radiation. In addition to differences in size and
proportion of proliferating cells of the thyroid in infants, children,
and adults, there may be significant alterations in absorption,
metabolic turnover, and cell sensitivity with advancing age. Any
of these factors might affect the amount of biological damage re-
sulting from a given radiation dose. Neither the relative impor-
tance nor the aggregate effect of these variables is known.
HUMAN EXPERIENCES
1. Direct Effects of Iodine 131
It has been pointed out that iodine 131 entering the body is
promptly and selectively concentrated in the thyroid gland, or is
[P. 2]
excreted. The direct radiobiological effects are thus confined to
the gland itself. The principal effects, which have been observed
only after high doses of radioactive iodine, include a decrease in
the metabolic activity of the gland, and at still higher doses, an
atrophy of epithelial cells, and the appearance of numbers of
atypical cells. These changes in function and structure are seen
only after doses of thousands of rads. Thyroid cancer is an un-
common result, described with certainty to date only in animals.
2. Indirect Effects Mediated Through the Endocrine System
The thyroid gland is one of the several endocrine organs of the
body whose activity is interdependent upon and responsive to dis-
turbance in the functions of other members of the system. For
example, when thyroid function is suppressed there is character-
istically an increased production by the pituitary gland of a hor-
mone that stimulates the cells of the thyroid. This mechanism is
the basis of an hypothesis that has been advanced to explain the
production of thyroid cancer by agents whose primary effect is to
7 Silver, S.: Radioactive Isotopes in Medicine and Biology. Medicine. Lea and Febiger, Phila-
delphia, 2nd ed., 1962, page 117.
-------
1282 LEGAL COMPILATION—RADIATION
impair thyroid function. The resulting over-stimulation of un-
impaired or slightly damaged cells by pituitary hormone is pre-
sumed to first induce hyperplasia or other effects which may then
occasionally progress to true neoplasia.
In the case of human beings irradiated as infants or children,
the incidence of thyroid neoplasms rises sharply during puberty
and adolescence. The high requirement for thyroid function dur-
ing this period of life presumably plays a powerful secondary role
in inducing neoplastic transformation of the irradiated gland.
The incidence of radiation-induced thyroid disease in this group
appears to fall off after age 20 to 25 years.
3. Other Indirect Effects in Cancer Induction
In the last report of this group it was stated that the probability
of developing thyroid cancer after irradiation is influenced by
factors other than endocrine effects or the direct action of radia-
tion absorbed in the thyroid gland itself. The reasons for this
statement were twofold: first, the apparent absence of a dose re-
sponse in thyroid cancer in persons treated with a wide range of
dosage; and, second, the remarkable variation in thyroid cancer
incidence in selected groups of children who received comparable
doses of X-rays to the thyroid but different doses to tissues other
than thyroid.
In the past four years the data on which these conclusions were
based have been reconsidered in the light of new estimates of thy-
roid doses in these cases under study. The radiation dose to the
thyroid depends strongly upon the exact location of the gland with
respect to the primary beam, as well as upon the air dose. By
estimating thyroid dose using reasonable assumptions as to beam
port placement, it is possible to show a strong dose response for
radiation-induced thyroid neoplasms. Furthermore, the remark-
able variation in incidence of thyroid cancer in selected groups of
persons who received comparable air doses of X-rays can be ex-
plained by the variation in thyroid dose resulting from variations
of the geometrical relations to the primary beam. Although the
possibility that irradiation of other tissues may have influenced
thyroid tumor induction cannot be excluded, it is not necessary to
invoke this hypothesis to explain the observations.
4. Diagnostic and Therapeutic Exposure to X-ray
a. Diagnostic X-ray
In various diagnostic procedures such as radiography of the
teeth, cervical spine, or larynx, and fluoroscopy of the larynx or
-------
GUIDELINES AND REPORTS 1283
esophagus, the thyroid gland may be exposed to a fraction of a
roentgen up to several roentgens. These are frequent procedures,
and to date no examples of cancer of the thyroid have been at-
tributed to such exposures. However, systematic effort to de-
termine such a relationship has not been made to our knowledge.
[P. 3]
b. Therapeutic X-ray
In radiation treatment of hyperthyroidism the thyroid gland
may be exposed to doses of several thousand roentgens. This pro-
cedure has been carried out on thousands of patients, and carci-
noma of the thyroid is an extremely rare complication.
Another practice, no longer in common use, is to treat sup-
posedly enlarged thymus glands in infants and children by expos-
ing the upper chest and neck to doses of 100 R to 600 R or more of
X-ray. When large treatment ports, particularly those placed
posteriorly, were used the thyroid gland often received the full
depth dose from the primary X-ray beam. Similar exposures of the
thyroid may result from X-ray treatment of enlarged cervical
lymph nodes or skin diseases. Subsequent studies of these pa-
tients, both retrospective and prospective, by several authors have
disclosed a small but significant incidence of thyroid cancer in
excess of the expected rate as determined by comparison with con-
trol groups of siblings. This indicates that the thyroid gland in
children is susceptible to cancer induction by radiation at relatively
high doses. Evidence at low doses is incomplete.
5. Exposure to Iodine 131
a. Diagnostic Procedures
The use of iodine 131 was introduced into clinical medicine about
25 years ago, and for 15 years it has been widely used in a variety
of diagnostic procedures. Most of these diagnostic procedures
utilize between 5 to 100 microcuries of iodine 131, and most of the
retained dose concentrates in the thyroid. No cases of thyroid
cancer induction have been reported in the patients who have
undergone these procedures.
b. Therapeutic Procedures
The principal uses of iodine 131 are in the treatment of hyper-
thyroidism and in the management of some cases of thyroid can-
cer. The latter cases must be excluded from present consideration
since the radiations were acting on tissues already cancerous.
-------
1284 LEGAL COMPILATION—RADIATION
There is little evidence 8 at hand that any of the treatments for
hyperthyroidism has produced a thyroid cancer, although doses
have ranged from a few thousand rads upward. Ablative doses
would in effect rule out the possibility of tumor induction.
From this and other evidence it appears that iodine 131 is con-
siderably less effective than comparable doses of externally applied
X-rays in producing thyroid cancer. The magnitude of this dif-
ference cannot be stated since not a single confirmed case ascrib-
able to iodine 131 is known. In making a comparison it must be
kept in mind that X-rays are ordinarily delivered at a high dose
rate in a single sitting or in a few divided doses; and the thyroid
as well as the blood vessels supplying it and the adjoining tissues
are uniformly exposed. In addition, the age of the patients treated
and their clinical conditions are rarely the same in the two
types of treatment. If the radiation were administered at the
same low dose rate of both iodine 131 and X-ray, the ostensible
difference might not be as great.
6. Reactor Accident
In a reactor accident radioactive iodine was released to the en-
vironment % and control measures were instituted to prevent hu-
man thyroid doses from exceeding 20 rads. No increase in the
incidence of thyroid neoplasia in this area has been reported, but
it must be remembered that the new complete effects of this epi-
sode will not be known for many years.
[p. 4]
7. Total Radiation Doses in Childhood Cancer of the Thyroid
Although thyroid cancer occurs in children who are not known
to have been exposed to artificially produced radiation, some his-
tory of X-ray exposure has been obtained by several workers in
well over half the cases in which careful inquiry has been made.
The X-ray doses received by most of these subjects are difficult to
determine, but by tracing the records of radiologists it appears
that the smallest doses associated with subsequent cancer range
upwards from about 100 R measured in air. Only a very small
number at these low levels have been reported.
8. Thyroid Abnormalities in a Marshallese Population Exposed to
Radioactive Fallout
The development of thyroid nodules and hypothyroidism has
been noted in a number of Marshallese people of Rongelap Island
8Staffurth, J. S.: Thyroid Cancer After 131-1 Therapy for Thyrotoxicosis. Brit. J.RadioI.
39:471-473,1966.
-------
GUIDELINES AND REPORTS 1285
in the Pacific who had been exposed to radioactive fallout in 1954.9
This development is believed to be a late effect of irradiation of the
thyroid gland from internal absorption of radioiodines and from
external gamma radiation at the time of the fallout. A total of 64
Rongelap people (54 living in 1966) received a whole body dose of
gamma radiation of 175 rads, extensive direct irradiation of the
skin from deposition of fallout thereon, and internal absorption of
radionuclides in the fallout. Eighteen other Rongelap people (14
living in 1966) received a lesser exposure of about 70 rads of
gamma radiation along with a smaller dose to the skin and in-
ternal absorption of less amounts of radioelements. A total of 157
individuals on the island of Utirik received a whole body gamma
dose of approximately 14 rads.
During the two-day period following the accident before the
evacuation of the people occurred, the inhabitants absorbed radio-
nuclides in the fallout by inhalation and ingestion of contaminated
food and drinking water. Based on radiochemical analyses of
pooled urine samples taken several weeks after the accident it was
estimated that the adult thyroid gland in the main Rongelap group
received about 160 rads from the radioiodine plus another 175 rads
from the external gamma radiation. Taken into consideration in
those calculations were the time and length of the fallout period,
the isotope energies and half-lives of the various iodine nuclides,
and the yield of the isotopes. Similar estimates for the smaller
thyroid glands of the young children ranged from 700 to 1400 rads
in the more heavily exposed group. Though "beta burns" were
prevalent in the neck region, it is believed the beta energies were
too weak to have contributed significantly to the thyroid dose. The
thyroids of the Utirik children received an estimated 55 to 125 rads
from iodine, plus the 14 rads from external gamma radiation.
In 1963, nine years after exposure to fallout, the first thyroid
nodule was detected in a 12-year-old girl in the more heavily ex-
posed group, and 2 further nodules were detected in 1964. In
March 1965, five other cases were noted, and in addition hypo-
thyroidism was diagnosed in two boys who had shown growth re-
tardation. Five further cases were detected in September of 1965
and 5 more in March 1966, making a total now of 16 cases with
nodules, plus two cases of hypothyroidism; '" only one nodule was
[P. 5]
found to be malignant. These cases are described in table I.
Table II summarizes the incidences of thyroid abnormalities in the
"Conard, E. A., Rail, J. E., and Sutow, W. W.: Thyioid Nodules as a Late Sequela of Radio-
active Fallout. New England J. Med. 247:1392-1399, 6/23/66.
10 Conard, R. A.: Personal Communication.
-------
1286 LEGAL COMPILATION—KADIATION
various populations examined. Note that 79 percent of children
less than 10 years of age at time of exposure in the more heavily
exposed group developed thyroid abnormalities, in comparison
with no thyroid pathology noted in children of the same age range
of the non-exposed population or in the lesser exposed populations.
The incidence in those exposed at a greater age is considerably
lower, and only slightly above that seen for the unexposed or less
exposed populations. It should be noted that the only nodules
noted in the unexposed population were in the older age group,
that is, greater than 50 years of age.
In most cases the thyroid glands contained multiple nodules
ranging in diameter from a few millimeters to a few centimeters.
All were non-tender, some firm, others cystic, and sometimes even
hemorrhagic. No lymphadenopathy was noted. The microscopic
sections of the benign lesions showed quite bizarre appearance
with a wide variety of different sized follicles, some small and
atrophic, others large with hyperplasia or cystic formation. The
hyperplastic changes were characterized in some cases by infold-
ing of the epithelium giving an arboreal appearance. These
changes resemble those seen in iodine deficiency goiter (adenoma-
toid goiter). The one case of cancer of the thyroid occurred in a
42-year-old woman and was of the mixed papillary and follicular
type.
A hypothyroid etiology for growth retardation noted in children
in the exposed group is strongly suggested by the findings of def-
inite hypothyroidism in two of the most retarded boys who had
atrophic glands but no nodules, and had a positive growth response
to thyroid hormone therapy. Their protein bound iodine levels
were below 2 microgram percent. Two other children with thyroid
nodules showed low values also.
The radiation etiology of these thyroid lesions appears to be
reasonably certain in view of the following facts: (1) The thyroid
glands received a substantial dose of radiation from radioiodines
and external gamma radiation. (2) Only a few older people in the
unexposed or low exposure groups have shown any nodules of the
thyroid gland. (3) the diet is not lacking in iodine and there are
no known goitrogenic foods.
9. Atomic Bomb Casualty Commission—Adults
The Atomic Bomb Casualty Commission has reported 14 cases
of thyroid cancer among survivors less than 1400 meters from the
hypocenter; 12 were found in the Hiroshima group, 2 in the Nag-
asaki group. These survivors had received external radiation;
radioactive iodine probably was not a contributory factor. The
-------
GUIDELINES AND REPORTS 1287
frequency of thyroid cancer appears greater in the Japanese pop-
ulation than in the United States. The estimates of thyroid cancer
range from 4.7 percent among all cases of thyroid disease in Jap-
anese hospitals,11 3.1 percent in a study made at the Kyoto Uni-
versity Medical School,1- to 13 percent at the University of
Hiroshima.13 Socolow 14 points out that although the over-all in-
cidence of thyroid cancer may not differ greatly among the atomic
bomb survivors, the age incidence does differ. Eight of his 21
cases were under 35 years of age, whereas at Kyoto 1L> 85 percent
of the cases were diagnosed after the age of 40. Three of Soco-
low's cases at Hiroshima were between 3000 and 3500 meters from
the hypocenter. These probably received little or no radiation on
the basis of the most recent recalculations of dose.15 The estimates
of doses given by Socolow for his cases range from 33 rads to
2620 rads.14 Seven of the thyroid cancers found in the two cities
developed in persons under 20 years of age at the time of the
atomic bombing. The estimated thyroid dose received by them
ranged from 256 to 2620 rads.
10. Fallout in Utah
In May 1953 Washington County, Utah, was thought to have
received an unusual amount of radioactive fallout from a nuclear
test at the Nevada test site. The exact dosage of iodine 131 from
[p. 6]
this fallout is not known, but estimates for the dose from iodine
131 to the thyroid gland range from less than 10 to above 400 rad.
Examination conducted in 1965 of school children in Washing-
ton County, Utah, revealed several thyroid abnormalities, but
nothing which can be specifically ascribed to radiation as an etio-
logical agent. Because of the fact that Washington County res-
idents seem, historically, to have had a relatively high prevalence
of thyroid disease and because children in Utah outside Washing-
ton County and in Northern Arizona at the time of fallout showed
the same frequency of the more severe thyroid abnormalities as
11 Sano, S. Konoc, K., and lokawa, N.: Statistics on thyroid diseases in Japan. Nihon Naibunpi
Gakkai Zasshi 34 (3) :230, 1958.
12 Miyake, T., Torizuka, K., and Kusakabe, T.: Epidemiology of thyroid disease in Japan.
Shindan lo Tiryo 50:783-796, 1962.
13 Kusunoki, N., Aoki, M., Nakagawa, S., and Masuda, T.: Diseases of thyroid gland. Hiroshima
Igaku Gencho 7 (6) : 1461-1467, June 1959.
14 Socolow, E. L., Hashizume, A., Neriishi, S., and Niitani, R.: Thyroid carcinoma in man
after exposure to ionizing radiation. A summary of the findings in Hiroshima and Nagasaki.
New England J. Mcd. 268:406-410, February 21, 1963.
13 Auxicr, J. A., Cheka, J. S., Haywood, F. P., Jones, T. D., Thorngate, J. H.: Free-field radia-
tion-dose distributions from the Hiroshima and Nagasaki bombings. Health Physics 12:425-429.
March 1966.
-------
1288 LEGAL COMPILATION—RADIATION
did the children who were in residence within the County, it is not
possible, from this particular study, to ascribe any degree of sig-
nificance to radiation exposure.
ANIMAL DATA
Data from animal experiments indicate that thyroid tumors
originate spontaneously less frequently and may be less easily
induced by radiation than tumors of some other organs. Thus leu-
kemia is frequent in numerous strains of mice, breast tumors com-
mon in rats, squamous cell carcinoma in white-faced cattle and
mast cell tumor in dogs; whereas, thyroid tumors were infrequent
in all except in regions where goiter is endemic. The two general
types of thyroid tumors are: (1) rounded, circumscribed, benign
nodules: adenomas; and (2) invasive, destructive growths: carci-
nomas. Adenomas do not necessarily develop into cancers but may
precede them. Ionizing radiation, as well as a number of chemical
agents, may induce either.
Most animal experiments with radiation have been done when
the animals were young, though not in infancy. However, a lim-
ited number of sheep at Battelle-Northwest (formerly Hanford
Laboratories) have been continuously exposed to various levels of
iodine 131 from conception to death (up to 10 to 12 years of age).
These animals have shown no thyroid tumors at dose levels giving
150 rads per year, but have shown adenomas after several years
with accumulated thyroid doses of 5,000 to 40,000 rads.
Two cancers involving the thyroid gland were seen at cumula-
tive doses of 10,000 and 30,000 rads. Thyroid exposures of 30,000
to 40,000 rads as a result of single doses of iodine 131 to young
adult sheep also resulted in many adenomas after 4 to 5 years.
When rats were subjected to radiation combined with sub-
stances producing goiter (which act by reducing thyroid hormonal
production and stimulating the pituitary), a few thyroid cancers
were produced by 1,100 rads of X-ray. About 15,000 rads were
required to produce a comparable tumor incidence when iodine 131
was used as the source of radiation.
When the head and neck are exposed to X-rays, up to 5 percent
of exposed rats may develop thyroid cancer. Parabiont rats de-
velop cancer of many organs readily when one of the pair is
given 1,000 rads of X-ray, but cancer of the thyroid is rare.
Whole-body doses of X-rays that readily induce leukemia in most
strains of mice very rarely produce thyroid cancer. Iodine 131
given to mice in large doses (delivering thousands of rads to the
thyroid) will heavily damage the thyroid without causing cancer
there, perhaps because of the many thyroid cells destroyed. How-
-------
GUIDELINES AND REPORTS 1289
ever, this may produce adenomas or cancers of the pituitary gland,
which is not itself significantly irradiated but is assumed to be
stimulated to abnormal activity and hyperplasia by the absence of
normal feedback from a functionally impaired thyroid.
The animal data are inadequate to permit firm conclusions, but
available information suggests that cancers of the thyroid are not
easily induced by radiation and that radiation from iodine 131,
largely restricted to the thyroid, is an even less efficient carcinogen
in laboratory animals than are X-rays.
[p. 7]
CONCLUSIONS
1. Therapeutic doses of X-rays to the thyroid region of children
have been followed after some years by the development of thyroid
neoplasms. Whereas the percent of cases of malignant neoplasms
is small, the proportion of persons irradiated who develop nodular
thyroid disease can be extremely high. The incidence of radiation-
induced thyroid disease is strongly dose dependent above 100 rads
(thyroid dose). The shape of the response curve below 100 rads is
unknown.
2. X-rays are probably as effective if not more so than iodine
131 in producing thyroid lesions for equal, average absorbed doses
delivered to the gland at similar rates. An apparent greater ef-
fectiveness of X-ray irradiation may be due to the higher dose rate
used.
3. Whereas it was formerly believed that the induction of thy-
roid tumors was enhanced by irradiation of tissues other than the
thyroid itself, it now seems possible to explain variability in tumor
induction in children on the basis of whether or not the gland was
in the primary X-ray beam.
4. Radioactive iodine in amounts sufficient to deliver several
hundred rads to the thyroid of the infant or young child has been
shown to produce a high incidence of thyroid nodules. Radio-
active iodine has been shown to be carcinogenic in some animals.
No case of thyroid cancer clearly ascribable to it has been reported
in man.
[p. 8]
-------
1290 LEGAL COMPILATION—RADIATION
TABLE I.—THYROID ABNORMALITIES IN EXPOSED RONGELAP PEOPLE, 1966
[Abnormality noted]
Case No. Present Age at
and Sex Age Exposure Years Age Findings
3, M 13 1 1965 12 Hypothyroid, FBI less than 2 ng% March 1965;
retardation of growth preceded these findings
by a number of years. 3/66 growth spurt and
improved appearance on hormone.
5, M 13 1 1965 12 Hypothyroid, FBI less than 2 u.g.% March 1965;
retardation of growth preceded these findings
by a number of years. 3/66 growth spurt and
improved appearance on hormone.
17, F 15 3 1963 12 Adenomatous goiter, complete thyroidectomy,
1964. No recurrence.
21, F 15 3 1964 13 Adenomatous goiter, complete para- and thy-
roidectomy, 1964. No recurrence.
69, F 16 4 1964 14 Adenomatous goiter, partial thyroidectomy,
1964. No recurrence.
2, M 13 1 1965 12 Adenomatous goiter, partial thyroidectomy.
1965. No recurrence.
20, M 19 7 1965 18 Adenomatous goiter, partial thyroidectomy,
1965. No recurrence.
64, F 42 30 1965 41 Mixed papillary and follicular carcinoma, thy-
roidectomy—surgical and with radioiodme,
1965. No recurrence noted.
72, F 18 6 1965 17 3 mm. nodule left lobe. No exam 3/66.
42, F 15 3 1965 14 2 mm. nodule right lower lobe; 3/66—nodular
enlargement entire gland; firm 5 mm. nodule
right lobe. 7/66 subtotal thyroidectomy. Ade-
nomatous goiter.
61, F 20 8 1965 19 6-8 mm. smooth nodule left lower pole; 3/66
1 cm. nodule left lobe. Subtotal thyroidectomy
7/66. Adenomatous goiter.
40, M 41 29 1965 40 2 mm. nodule right lower pole; 3/66 no no-
dules detected.
59,* F 46 34 1965 45 5 mm. nodule midline; 3/66 same. Subtotal
thyroidectomy 7/66. Adenomatous goiter.
54, M 13 1 1966 13 Nodular enlargement left lobe and isthmus
with 2 mm. firm nodule.
19, M 17 5 1966 17 Multmodular soft goiter—gland IVz normal
size; 1 cm. nodule right lower pole.
36, M 19 7 1966 19 About 1 cm. nodule—not clearly demarked—
right lower pole. Many tiny nodules surface of
gland.
33f F 13 1 1966 13 In 9/66 questionable irregular gland. 3/66
definite 5 mm. nodule left lobe. Subtotal
thyroidectomy 7/66. Adenomatous goiter,
Hurthle cell adenoma.
65, F 13 1 1966 13 In 9/65 questionable small nodule; 3/66 a 5
mm. nodule right lobe. 7/66 right subtotal
thyroidectomy. Adenomatous goiter.
* Exposed to only 69 rads whole body radiation and presumably proportionately less thyroid dose.
[p. 9]
-------
GUIDELINES AND REPORTS
1291
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-------
1292 LEGAL COMPILATION—RADIATION
4.2b RADIATION EXPOSURE OF URANIUM MINERS,
REPORT OF AN ADVISORY COMMITTEE FROM THE
DIVISION OF MEDICAL SCIENCES: NATIONAL ACADEMY
OF SCIENCES—NATIONAL RESEARCH COUNCIL-
NATIONAL ACADEMY OF ENGINEERING, FEDERAL
RADIATION COUNCIL, AUGUST 1968
PREFACE
A special subcommittee of the National Academy of Sciences—
National Research Council Advisory Committee to the Federal
Radiation Council was appointed at the request of the Council staff
to prepare this report on "Radiation Exposure of Uranium Min-
ers." The report includes information available through July 1968
and is based on contributions of individual subcommittee members,
a meeting of the subcommittee on May 2, 1968, a meeting of the
full committee on June 25, 1968, and subsequent correspondence.
The members acted as individuals, not as representatives of their
organizations.
Cyril L. Comar
Chairman, Subcommittee on Radiation
Exposure of Uranium Miners
Howard L. Andrews Brian MacMahon
Victor P. Bond Paul E. Morrow
George W. Casarett Eugene L. Saenger
Averill A. Liebow Shields Warren
This report was approved by the Advisory Committee to the
Federal Radiation Council.
Cyril L. Comar
Chairman
Seymour Abrahamson Brian MacMahon
Howard L. Andrews Joseph E. Rail
Victor P. Bond William L. Russell
George W. Casarett Eugene L. Saenger
Louis H. Hampelmann Shields Warren
Samuel P. Hicks
[p. iii]
-------
GUIDELINES AND REPORTS 1293
CONTENTS
Page
Preface iii
Section I. Introduction , 1
Section II. General Considerations in Establishment of Guidance 2
A. Background 2
B. The Problem of Guidance 2
C. Approaches 2
Section III. The Working Level Concept 6
A. General 6
B. Methods and Measurement 6
C. The "Free-Ion" Controversy 8
D. Lung Models 8
E. Correlation of Bone Levels 9
F. Quality Factors 10
Section IV. Dose-Effect Relationships 11
A. Considerations of Carcinogenic Mechanisms in General 11
B. Considerations of Radiation Dose Threshold in General 12
C. The Relevant Dose in Protracted Irradiation 13
D. Dose-Effect Relationships—General 13
E. Dose-Effect Relationships—Assumptions 14
Section V. Pathology 16
Section VI. Epidemiology 19
A. The Question of a Cause-Effect Relationship at 100
to 400 CWLM 19
B. Synergistic Effect of Cigarette Smoking and Uranium Mining 21
Section VII. Conclusions 23
References 25
Appendix
[p. v]
TABLES
1. Expected and observed respiratory cancer deaths in relation to esti-
mated cumulative exposure to airborne radiation and years after
start of uranium mining—white underground miners, 1950-
September 1967 inclusive 29
2. Description of respiratory cancer cases and deaths among study
group of underground uranium miners, 1950-September 1967
inclusive, listed in order of increasing estimated WLM 29
[p. vi]
RADIATION EXPOSURE OF URANIUM MINERS
SECTION I. INTRODUCTION
1.1 Increasing attention has been given, within recent years, to
observations that extended exposure in some uranium mines is as-
sociated with an increase in lung cancer. Upon approval by the
Federal Radiation Council (FRC), its staff carried out a study on
the radiation hazards associated with the underground mining of
-------
1294 LEGAL COMPILATION—RADIATION
uranium ore. A preliminary draft of the staff report was pre-
pared for use in hearings on "Radiation Exposure of Uranium
Miners" held by the Joint Committee on Atomic Energy during
the summer of 1967. The FRC staff report, Report 8 Revised,
"Guidance for the Control of Radiation Hazards in Uranium Min-
ing" (1), was issued in September 1967. The published two-part
record and summary analysis of the hearings (2) and the FRC
staff report constitute a most comprehensive collection of relevant
data and viewpoints. The broad objectives were to determine
whether uranium miners were being protected by adequate stand-
ards and to ascertain how low an exposure would be necessary to
insure a proper level of safety for the miners. This necessarily
led to considerations of risk versus benefit and to examination of
the scientific basis for estimating the magnitude of risk associated
with low levels of exposure.
1.2 It was apparent that the subject was most complex and that
divergent viewpoints were held on many important issues.
1.3 Accordingly, it was intended that an interpretative report
be prepared by persons competent in related areas of radiobiology,
but not necessarily having intimate connection with specific aspects
of uranium mining. This report has three major objectives: (a)
evaluation of the degree of reliability that can be assigned to con-
clusions from present data, (b) indication of urgent problems that
need to be answered to provide adequate reliability for future con-
clusions, and (c) clarification of the best possible basis for
decisions that have to be made now before completely adequate in-
formation becomes available. There is included only such factual
material as is necessary for understanding of the viewpoints pre-
sented. Reference can be made to previously mentioned reports
for additional details.
[P. 1]
SECTION II. GENERAL CONSIDERATIONS IN ESTABLISHMENT OF
GUIDANCE
A. Background
2.1 It has been known for centuries that numerous miners who
worked for several years in mines in which pitchblende was pres-
ent developed fatal pulmonary disease. This was recognized par-
ticularly in Schneeberg in the Erz Mountains in Saxony, and in
Joachimsthal on the Bohemian side. The possibility was put forth
first in the 1920's that lung diseases, particularly carcinoma, might
be associated with high levels of radon in the mines. This theory
was further developed in the thirties and forties, and now there
-------
GUIDELINES AND REPORTS 1295
seems to be little question that inhalation of the mine air played
an etiologic role in the development of cancer.
2.2 Epidemiologic studies during the 1950's on men working in
uranium mines in the United States also indicated an increased in-
cidence of lung carcinoma. Additional studies have confirmed this
and have suggested an additive and perhaps synergistic effect
between exposure in the mines and cigarette smoking. There thus
seems to be no question that extended exposure in some uranium
mines is associated with an increase in lung cancer. There is fur-
ther evidence that the incidence may be correlated with the product
of the length of time worked and the average concentration of
radon and its daughter products during that time. There is no
absolute proof that exposure to radiation is in fact the etiologic
factor in the development of lung carcinoma under these circum-
stances; however, few, if any, would question the high probability
that radiation exposure does play a definitive role.
B. The Problem of Guidance
2.3 A specific problem at hand is to decide on the most objective
approach to determining the limits of exposure for uranium min-
ers independently of any considerations of actual values that a
given approach might yield. Many philosophies exist with respect
to what should be the "allowable" exposure for any noxious agent.
Broadly speaking, they range from the thesis of "zero" exposure
and hence zero additional effect, to various figures for exposure
that are presumed to result in some definite but "tolerable" in-
crease in the probability of occurrence of harm. Short of barring
all exposure and thus reducing the risk to zero, all philosophies,
however lax or rigid they may be, involve implicitly or explicitly
an evaluation of the degree of risk as a function of exposure to or
dose from the noxious agent. The problem, then, is essentially to
decide whether an objective basis can be found for evaluation of
dose-effect relationships with respect to the uranium miners.
C. Approaches
2.4 There are two fundamental approaches to the problem—
the "empiric," based on epidemiologic data, and the "theoretical,"
based on hypothesis and calculation.
2.5 With respect to the empiric approach, studies conducted in
the United States have resulted in the accrual of a large amount of
data on the incidence of lung carcinoma in uranium miners (1,2).
[p. 2]
-------
1296 LEGAL COMPILATION—RADIATION
Estimates of the degree of exposure, expressed in WLM,1 have
been made for such persons, even though physical measurements
on which to base the estimates were not available in a large pro-
portion of the cases. On the basis of these estimates, however, an
attempt has been made to construct an exposure-effect curve (ref.
(1), p. 22). By appropriate curve fitting, one can attempt to
determine the nature of the exposure-effect relationship and can,
in principle, then extrapolate to determine some exposure level that
will result in some acceptable degree of risk.
2.6 The analogy to this approach is found in the use of human
data on radium-dial painters and others who received radium in-
ternally, in establishing the present maximum permissible body
burden (MPBB) for radium of 0.1 /iCi total body burden. Epi-
demiologic studies on the persons so exposed to radium were con-
ducted, and disease and mortality associated with the radium
exposure were evaluated. Estimates of radium body burden were
made. The primary data for establishment of the MPBB lie in
the curve of degree of effect in human beings versus body burden
of radium in microcuries (2A). The introduction of a suitable
safety factor led to the 0.1 ^.Ci MPBB, which is still extant and
which is the prime standard for setting the MPBB for bone seek-
ers. It should be noted that although large numbers of calculations
of absorbed dose in rads and of dose equivalent in rem from the
radium body burdens have been made, such calculations are not
necessary for and are not used in establishing the body burden of
0.1 fiCi of radium. The primary approach is to use dose-effect data
from human beings, with dose in terms of /uCi of radium.
2.7 The second approach (theoretical), which is in principle
completely distinct from the first, involves the establishment of
hypothetical dose-effect relationship; that is, the establishment of
some exposure expressed in quantities of dose equivalent (units
of rem), which will result in some presumably acceptable but un-
specified increased individual risk. An acceptable risk to a per-
son implies a high probability of escaping injury altogether. A
1 Working Level (WL): A level of concentration or burden of radioactivity in a given air
environment. Related to environments containing ladon and daughter products of radon, a
WL is represented by any combination of short-lived radon daughters in 1 liter of air that will
result in the emission of 1.3 X 103 MeV (million electron volts) of potential alpha eneigy from the
radioactive decay of the radon daughters. This numerical value is derived from the alpha
energy released by the total decay of the short-lived radon daughter products at radioactive
equilibrium with 100 picocuries of radon-222 pel liter of air.
Working Level Month (WLM): A unit of radiation exposure obtained from working in an
environment of 1 WL for 1 month (170 hrs.). (For example, 12 months at 1 WL = 12 WLM; 12
months at 0.3 WL = 3.6 WLM.) Most standards piovide a further restriction on exposure, that
no quarter of the work year shall involve greater than half the permissible annual total; for
example, in the first case above, G WLM; in the second, 1.9 WLM. The designation CWLM is often
used to represent Cumulative Working Level Months.
-------
GUIDELINES AND REPORTS 1297
variety of hypothetical dose-effect relationships can be invoked, but
the one most commonly used is the "linear no-threshold" hypo-
thesis because it is felt to be the "safest." In principle, one could
establish an excess incidence of effect or increased individual risk
that is deemed to be acceptable and determine the corresponding
exposure in rem, on the basis of the hypothetical dose-effect re-
lationship chosen. Actually, what appears to be more common is
simply the establishment of an exposure (usually exposure rate),
expressed in rem, with no incidence figures attached. With respect
to the lung, a dose-equivalent rate of 15 rem/year is established
(see pp. 642 and 643 of Part 1 of the hearing (2)). It must be
emphasized that the 15 rem per year is not based on direct evidence
(in the human being or in animals) that any ill effects or any par-
ticular degree of risk would be associated with this exposure rate.
The number represents a "best estimate," arrived at in the ab-
sence of data on actual dose-effect relationships. It should also be
emphasized that the 15 rem per year is a value for dose-equivalent
rate averaged over some macroscopic tissue volume; no cumula-
tive total dose equivalent that will result in an "acceptable" level
of damage is given.
2.8 Once the "allowable" dose to the assumed critical tissues is
established, it is necessary to calculate the exposure in terms of
radioactivity in the mine atmosphere that would lead to this dose-
equivalent rate. A number of assumptions are involved in the
calculations, including:
(a) the value for the RBE (relative biologic effectiveness) for
alpha emitters, for carcinoma of the human lung (this value is not
[p. 3]
shown and must be estimated) ;
(b) the "critical tissue" in which the tumor is formed (it is not
certain in what tissue or in what portions of the lung these tumors
arise);
(c) the effect of nonuniform dose distribution (the degree of in-
fluence of "hot spots," as contrasted to an "average" tissue or
organ dose, is unknown but may well be important);
(d) the model that describes the kinetics of cell proliferation in
the presumed critical tissue, commonly taken to be the bronchial
epithelium (available models vary widely, and the dose and dose-
rate to tissues are highly dependent on the model selected); and
(e) the amount of radioactivity deposited per unit time in the
presumed critical tissue, for a given level of radioactivity in the
atmosphere of the mine.
2.9 Both broad approaches, the empiric and the theoretical, in-
volve many errors and assumptions. In an effort to decide whether
-------
1298 LEGAL COMPILATION—RADIATION
one has merit over the other, the following broad principles are
offered.
(a) It is best, whenever possible, to work from actual dose-
effect data relating 'to the organ and exposure conditions of
interest.
(b) It is better, whenever possible, to apply available data on
human beings than on animals.
(c) If data on the human being are not available, or are felt
to be so scanty and poor as to be essentially unusable, then dose-
effect relationships established for animals should be used, if
available.
(d) The use of hypotheses of dose-effect relationships and
necessary calculations to arrive at exposure levels should be re-
served for situations in which the human or animal data are such
that the relative error in the empiric approach is definitely greater.
2.10 In regard to the uranium miners, data on exposed human
beings are available. The precedent exists, as already described
for radium, for using epidemiologic data of this nature in estab-
lishing guidance. It is necessary to attempt to assess the relative
error involved in the two approaches. With the empiric approach,
as indicated, the error is large. It is possible, however, to place
limits of error on the dose-effect relationship obtained (one can
obtain a curve to describe the dose-effect relationship simply by ob-
taining a least-square fit of the data); alternatively, one can at-
tempt to impress on the data a curve that fits some hypothesis.
The theoretical approach also carries potentially large errors, to
many of which no limits of error can be assigned. The largest un-
certainty lies in the assumption that 15 rem per year will lead to
some degree of effect that will be acceptable. There is no way of
putting limits of error on this assumption because it is an "ed-
ucated guess." The second largest assumption, again with no
limits of error, involves the amount of radioactivity deposited in
the critical tissue per unit of exposure to radiation in the atmos-
phere. Other sources of error include the particular lung model
adopted, the effect of nonuniform exposure, translocation of radio-
activity, and uncertainty as to the critical tissue.
2.11 We are thus faced with two approaches, each with a large
uncertainty. The degree of error can be assessed in the empiric
approach; it is essentially unassessable in the theoretical approach.
Also, with the theoretical approach, a long chain of potentially
large and unassessable errors are involved, which are multiplica-
tive. In the absence of an absolute assessment of the degree of
error in each approach, it is not possible to decide objectively, on
the basis of degree of error, which approach is the more objective.
-------
GUIDELINES AND REPORTS 1299
It is clear, however, that there is no compelling reason to use the
theoretical approach on the basis of relative probable error. For
the future, errors in the empiric approach may be reduced by the
availability of more data on effects, but the errors may also be in-
creased because of reductions in the levels of exposure that have
gone into effect. Nevertheless, there are strong reasons at present
for using and improving the empiric approach in arriving at guid-
[p. 4]
ance for exposure of uranium miners.
2.12 The above conclusion is in no way intended to discourage
efforts to calculate dose or to downgrade the importance of under-
standing and quantitating dose-response relationships in radio-
biology and in radiation protection. On the contrary, every effort
should be made to improve dosimetry, so that more meaningful
calculations can be made. Eventually, the theoretical approach
may provide better understanding of the various factors involved
and permit generalizations to other exposure situations.
2.13 Regardless of approach, it is necessary to inquire into the
reliability of estimates of the dose and of the effect produced. As
a starting point, it is usually assumed that the estimation of radio-
activity in the ambient atmosphere bears a constant relationship
to the radiation exposure. Further refinement and understanding
come from consideration of physical and physiologic processes in
the lung, although, with present information, it is doubtful that
such considerations contribute practically to quantitation of rad-
iation dosage. The status in regard to both atmospheric measure-
ments and lung processes is presented in section III. The effects
are discussed in sections V and VI.
[p. 5]
SECTION III. THE WORKING LEVEL CONCEPT
A. General
3.1 The Working Level1 refers to a concentration level or bur-
den of short-lived radon daughter products in a given air environ-
ment, and present epidemiologic data are based on the Working
Level Months (WLM) as the unit of radiation exposure in the
dose-effect relationship. It is evident that the Working Level was
designed to represent the radiation exposure potential of uranium
mines in the face of a variety of nonequilibrium conditions. It is
unsatisfactory for two reasons. First, there are inherent dif-
1 See footnote 1, p. 3.
-------
1300 LEGAL COMPILATION—RADIATION
ficulties in sampling methods and instrumentation; this is by no
means unique to uranium mines nor to the Working Level con-
cept, but occurs with all types of air-sampling programs. There
are partial remedies based on proper decisions, such as those con-
cerning the type and number of samplers and the number and
duration of samples taken. Second, the Working Level, con-
ceptually and in practice, gives no recognition to the relative
contributions of the various radon decay products to the radiation
dose and, in particular, fails to recognize the "free-ion" fraction.
There is an appropriate and apparently successful instrument-
development program underway in both area and personnel dos-
imeters; thus, much of the instrumental inadequacy soon may be
eliminated.
3.2 Assuming that the problems other than instrumental can
and will be overcome, we might reasonably expect that the Work-
ing Level measurements in combination with information about
the worker's activity, respiratory physiology, and associated en-
vironmental factors can be amalgamated into a reasonable esti-
mate of exposure in the future.
B. Methods and Measurement
3.3 Measurements of radon and airborne daughters are still
being made by the methods described in Public Health Service
Publication 494. This document originally appeared in 1957 and
was submitted to the hearings (2) in 1967 as representing con-
temporary procedure. The methods are time-tested and satisfac-
tory in competent hands, and there seems no reason to question
the figures obtained by using them.
3.4 Some field measurements of radon concentration have been
made with scintillation detectors, but these probably do not have
the accuracy of the laboratory assays.
3.5 A sample for the radon daughter determination is obtained
by pulling a known volume of air through a filter paper, which is
subsequently assayed in the laboratory. The laboratory assays
can be expected to have the usual random error distribution, above
and below the true value, but this may not be the case for the
sample collection. Most of the operational uncertainties will tend
to reduce the amount of material collected, and hence lead to an
underestimate of the airborne activity. If representative samples
are to be obtained, the field personnel must be well trained.
3.6 Monitoring efforts have properly concentrated on radon
daughters, because they are responsible for the greatest propor-
[P. 6]
-------
GUIDELINES AND REPORTS 1301
tion of the airborne hazard. Some 1,200 mines are under sur-
veillance, in which about 12,000 determinations of radon daughters
have been made over a 10-year period. This averages to about one
sample per mine per year, but the distribution is far from uni-
form. In some mines where disturbingly high concentrations were
found, series of closely spaced measurements may have been made
as corrective measures were instituted. In some mines, no mea-
surements have been made.
3.7 Uranium mines may be classified by a variety of character-
istics, such as depth, degree of wetness, rock porosity, and
character and extent of ore bodies. Correlations of these char-
acteristics with measured values of airborne radioactivity permit
an estimate of activity levels in unmeasured mines. Experienced
workers have more confidence in these estimates than most out-
siders would anticipate.
3.8 Exposure values assigned to the period before 1956 are
highly unreliable, being based almost entirely on estimates rather
than measurements of concentrations. The sampling frequency
increased with time, but some of the 1956-1960 values may never-
theless be in error by an order of magnitude. Values for the
period after 1960 are the most reliable, but even here many of the
Working Level values reported are only estimates, no measure-
ments having been made.
3.9 There is some uncertainty in the average Working Level
values even in mines in which a number of measurements have
been made. Each assay depends of necessity on a spot sample,
representative only of the conditions existing at the time and place
of sampling. The usefulness of spot samples in estimating aver-
age exposure levels has been evaluated (3) and found to be ac-
ceptable, if not ideal. Errors in the techniques of sampling and of
field assay methods have been estimated to be less than 10 percent
under favorable conditions (4)- The conditions can vary widely
with the nature of mine operations, such as blasting, ventilation,
and amount of ore uncovered. The mine air may be almost free
of dust and fumes, so that the radon daughters, created as in-
dividual nuclei, may exist in an essentially gaseous state for an
appreciable period. However, Diesel engines may be running, pro-
ducing soot particles that serve as condensation nuclei, hydro-
carbon residues of various sorts, and carbon dioxide. The variable
concentrations of these chemical contaminants introduce both
physical and biologic uncertainties.
3.10 The physical uncertainties have been demonstrated by the
finding of different particle size distributions and lung depositions
between an operating and a quiescent mine environment. Vir-
-------
1302 LEGAL COMPILATION—RADIATION
tually nothing is known about any additive or synergistic effect
of radiation and other common mine contaminants, such as arsenic,
copper, germanium, lead, and zinc. Concentrations of these ele-
ments are detectable but are probably too low to be of biologic
significance. Opinions on this point are by no means unanimous.
3.11 The problem of determining an individual uranium miner's
radiation exposure is complicated by the fact that official mine rec-
ords do not necessarily show his actual job assignment. Only the
miner himself, and to a lesser extent his immediate supervisor,
know the areas in which he has worked. Another problem is pos-
sible exposure from previous mining experience. Retrospective
information of this type is of dubious validity.
3.12 The latent period for tumor induction makes the early
values of exposure and dose particularly important. It is un-
fortunate that, of the present data on uranium miners, these
important early exposure values are the least reliable.
3.13 In addition to uncertainty in the physical measurements,
there are great variabilities in the actual radiation dosage as de-
livered to the critical tissues, depending mainly upon physiologic
and physical processes in the lung. These are discussed below.
[p. 7]
The "Free-Ion" Controversy
3.14 In the evaluation of Working Levels, the concentration of
free ions (RaA) is a key issue because of its presumably important
contribution to the radiation dose and dose rate received by the
bronchial tree. The controversy over what values to use for the
free ion-fraction seems unresolvable at present and probably will
remain so, in view of the wide range of free ion values reported in
mine atmospheres. One possible solution to the problem is, of
course, to avoid trying to settle on a "universal" value and, instead,
to use measured values for each circumstance.
3.15 The deposition characteristics of free ions on small molecu-
lar aggregates of the radon decay products within the human
respiratory tract have been studied by several investigators. (5-
10). The average desposition value appears to be about 35 per-
cent. Recent data obtained at the Beaverlodge mines by personnel
from the NYO Health and Safety Laboratories (11) give a mean
deposition value of 38 percent, with a standard deviation of about
15 percent. With large tidal volumes (> 1 liter), the total de-
position for radon decay products generally exceeded 50 percent.
Investigators at the Health and Safety Laboratories have also
measured the nasal deposition of free ions; their reported values
generally exceed 60 percent, and average about 65 percent. The
-------
GUIDELINES AND REPORTS 1303
widely accepted value of about 25 percent nasal deposition for free
ions, obtained experimentally by Chamberlain and Dyson (12), is
lower than diffusion theory predicts, and lower than that deter-
mined in other studies with aerosols of comparable diffusivity.
Increasing the free ion deposition in the nasal passages will corre-
spondingly reduce tracheobronchial dose estimations.
3.16 A variety of papers (5, 8, 11, 13, 14) indicates that in ura-
nium mine atmospheres the alpha activity derived from radon
decay products is associated exclusively with particles below 0.5
/tm in diameter. In most instances, the major part of the activity
appears to be on particles well below 0.1 /tm. Mine atmospheres,
however, have quite different aerosol distributions; commonly, the
mine aerosol has a mass median diameter greater than 1 ^m and
a count median diameter less than 0.5 ^m. There is no evidence
that the alpha activity is distributed on the mine (vector) aerosol
distribution in a predictable way. Estimates of the surface area
distribution (based on geometric configuration of particles and not
specific surface-area measurements), for example, fail to give an
activity distribution corresponding to actual measurements. It is,
probable, therefore, that the activity is distributed more closely
to the numerical distribution.
3.17 The Task Group Report on Lung Dynamics (15) dealt
with this general topic in a limited way. It suggested, among
other things, that the nasal efficiency is increasing for particles
below 0.01 [j.m and that the graphic representations of size-
deposition used in the report were not designed to handle aerosols
composed primarily of such minute particles. In fact, the Task
Group considered the whole area as a special problem. A second
Task Group was later organized under ICRP Committee 2 to in-
vestigate this problem in detail. There has been no formal report
from this group.
D. Lung Models
3.18 It now appears technically feasible to obtain suitable air-
sampling information for assessment of exposure conditions in
uranium mines. To evaluate this information more directly in
terms of hazard potential to the worker, some knowledge of the
intermediate processes is necessary. One approach is to draw on
the established physical-chemical properties of the atmospheric
contaminants and apply them to a physiologic and anatomic model
of the respiratory system. The development of a lung model not
only provides for expressing air-sampling information in terms of
dose to the tissue, but also divides the relationship into its com-
ponents. The significance of individual factors is thereby subject
-------
1304 LEGAL COMPILATION—RADIATION
to assessment, and the possibility of modifying these factors is
[p. 8]
brought into focus; in addition, recognition is given to areas for
which information is lacking, uncertain, or controversial.
3.19 Several models have been developed specifically for the
radon daughter problem; those of special merit have come from
Altshuler and coworkers (16), Jacobi (17), Thomas (18), and
Haque and Collinson (19). These epitomize the degree of sophis-
tication currently possible, and it is considered that they cannot be
improved on, in principle, to any important extent. There are,
however, small but significant differences among these models, and
these have rather important effects on the ultimate estimation of
dose. One of the more significant distinctions has already been dis-
cussed; that is, the daughter ratios and the amount of free ions
assumed present in the exposure. Other important distinctions
include the anatomic dimensions of the bronchial tree, the thick-
ness of the mucous and the bronchial cell layers, the presence or
absence of effective mucociliary clearance, and the presumed dep-
osition pattern. It is not productive to study these models and
decide that this or that assumption is more likely correct, because
these investigators have all drawn their ideas and assigned values
from a body of information that lacks consistency and complete-
ness. Perhaps in a few instances it would be possible to state
preferences because of new information or information that might
not have been known to the persons involved. Still, when the
various models are used with the same kind of Working Level
assumptions, they tend to give approximately the same kind of
dose estimate to the bronchial tree; that is, they range within a
factor of about 6, and this includes the effect of assuming that
different areas of the bronchial tree receive the greater dose.
3.20 The effective half-life of radon daughter products was
estimated, using several of the lung models, on the assumption of
a 15-minute exposure. The theoretical elimination curves from
the foregoing models predict an effective half-life around 15 to 18
minutes. Experimentally determined effective half-lives for radon
decay products in the lungs have been found to average 37 minutes
in subjects studied by external counting methods after inhalation
exposures to mine atmospheres (9). This half-time value essen-
tially corresponds to that of radium-C decay.
3.21 Although the data are limited, clearance measurements for
radon decay products generally give effective half-times somewhat
longer than those obtained in other human studies of tracheo-
bronchial clearance using radioactively labeled aerosols (20). This
is probably due to a more peripheral deposition pattern for the
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GUIDELINES AND REPORTS 1305
smaller particles serving as a vector for the radon decay products;
in addition, there is a possibility that, after deposition, the radio-
nuclei rapidly dissociate from the aerosol particles (21) and later
experience adsorption to and absorption by the bronchial epithelial
cells. Whatever the explanation, there now seems to be ample in-
formation to substantiate the view that radon decay products
(radium-A to radium-C) undergo negligible biologic clearance
from the human bronchial tree.
3.22 In summary, existing lung models and dosimetry use dif-
ferent assumptions, but starting with a relatively uniform expo-
sure basis (a similar ratio of daughter products and percentage of
free ions), they give an exposure equivalent estimate of about 7
± 5 rad per WLM (1, 2, 18, 19, 22).
E. Correlation of Bone Levels
3.23 A novel approach to the exposure-radiation dose relation-
ship in uranium miners has been undertaken by Black and co-
workers (22). They attempted to correlate the bone levels of
lead-210 with estimated exposures (WLM). A key assumption in
their development depends on the relation between the lung burden
of lead-210 and the amount redistributed to bone; this apparently
varies from about 10 percent to 65 percent. Black and coworkers
selected 22.5 percent, and obtained approximately the same rad
[p. 9]
dose to the bronchial tissue per Working Level Month as is deter-
minable by the various lung models, viz., about 2 rads. There are
still large uncertainties involved in this interesting approach that
require further substantiation.
F. Quality Factors
3.24 The published literature gives no adequate basis for assign-
ing a quality factor for alpha particles where lung carcinoma is
concerned.
[p. 10]
SECTION IV. DOSE-EFFECT RELATIONSHIPS
A. Considerations of Carcinogenic Mechanisms in General
4.1 To derive meaningful conclusions from the sparse data on
uranium miners and to use experience from the clinical radium
data, it is necessary to understand some of the general aspects of:
(a) carcinogenic mechanisms, (b) time patterns of cancer induc-
tion, (c) wasted radiation, and (d) shapes of dose-effect curves,
-------
1306 LEGAL COMPILATION—RADIATION
particularly in regard to thresholds and the linear hypothesis (2,
23).
4.2 Cancers caused by radiation cannot be pathologically distin-
guished from the same types of cancers resulting from other
causes. They can be distinguished only statistically with respect
to their incidence in irradiated populations, compared with control
populations.
4.3 None of the many types of changes that radiation can cause
in cells or tissues is specific or unique for radiation. These types
of changes can be caused by a variety of agents or conditions, in-
cluding many of those known or suspected to be carcinogenic or to
promote carcinogenesis. Some of the effects of radiation seem to
be additive to carcinogenic or promoting effects of other agents
and conditions.
4.4 The precise mechanisms of carcinogenesis are not known
completely. Available information indicates that most, if not all,
types of cancer develop as a result of multistage or multievent
mechanisms, including: (a) initiating cellular events that change
the cells of origin of the potential cancer in a manner (chrom-
osomal or other organelle aberrations, mutations) that confers on
them neoplastic potential, and (b) promotional events, in which
further changes in cells or in local or systemic environment act on
the potentiated cells to change them or permit or stimulate them to
proliferate as cancer cells. The precise number and nature of the
cellular and environmental events for any type of cancer are not
known.
4.5 Carcinogenic mechanisms can involve events occurring at
any time from the prezygotic stage to the time of cancer appear-
ance. They can involve: (a) prezygotic (inherited) cell muta-
tions, which can spread during development to all kinds of cells;
(b) postzygotic somatic-cell mutations acquired throughout life;
(c) viral factors; and (d) changes in systemic factors (depressed
immune competence, hormonal imbalances) and in local tissue
(disorganization and damage), which result from the many path-
ologic or inherent processes that occur with time. These latter
include the changes in cells and tissues caused by a variety of en-
dogenous and exogenous carcinogenic initiating and promoting
agents. The incidence of lung cancer, for example, tends to in-
crease with advancing age.
4.6 Radiation can cause all the changes required to induce can-
cer; however, it may be only one of the causes. Even small doses
of radiation can cause cellular changes, including chromosomal
aberrations and cell mutations, some of which have been implicated
as initiating cellular events in carcinogenesis. In large doses,
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GUIDELINES AND REPORTS 1307
radiation can, in addition, cause tissue disorganization and phys-
iologic changes that are essential or contributory to carcinogenesis.
Although there is as yet no consensus as to the mechanism of
radiation-induced carcinogenesis, the following have been sug-
[p. 11]
gested: (a) production of ions and inorganic radons, with hydro-
gen peroxide formation in aqueous systems, (b) direct production
of somatic mutations that predispose to the development of cancer,
and (c) activation of oncogenic viruses (although virus-induced
cancers have not yet been found to occur in man). With regard
to the first hypothesis, it has been suggested that a number of or-
ganic peroxides have carcinogenic properties, and that peroxides
in general may act by catalyzing the depolymerization of DNA and
RNA.
4.7 As already implied, lung cancer is apparently preceded by
considerable local tissue damage and disorganization. The expe-
rimental induction of lung cancer by irradiation of normal animal
lung requires large radiation doses, but the required doses are
reduced if local tissue damage and disorganization are caused by
other means. In addition to radiation, other factors may play a
role in the etiology of lung cancer in uranium miners, including:
(a) cigarette smoking, (b) Diesel exhaust fumes, (c) uranium ore
dust, (d) upper respiratory and viral infections, (e) nitrogen
oxides derived from explosives, and (f) hydrocarbon mists from
oil-lubricated pneumatic drills.
4.8 The relative contribution of any particular radiation expo-
sure to the induction of a particular cancer and the radiation dose
required to induce the cancer in a person (individual dose thresh-
old) depend on the extent to which the rest of the carcinogenic
mechanism will have been completed by changes caused by factors
other than the exposure in question. Obviously, the age or life
expectancy of the person at the time of exposure and relation to
the required time for induction and development of the cancer is
one of the determining factors in the individual dose threshold or
susceptibility to radiation induction of the cancer. In this regard,
there is ample experimental evidence, at least for cancers that in-
crease in incidence with age, that the time between irradiation and
the appearance of radiation-induced cancer increases as dose
decreases.
4.9 The effect of a radiation exposure in radiation carcinogen-
esis in a population may be either (a) to cause earlier induction
and development of cancers (temporal advancement) in persons
who would have had the cancers eventually without the exposure,
or (b) to cause cancers (absolute induction) in persons who would
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1308 LEGAL COMPILATION—RADIATION
not have had the cancers otherwise. The yield of cancers in any
given period after exposure will be determined by which of these
processes or what combination of them applies among the cancer
cases, and by any changes in survival time caused by the exposure.
The difference between temporal advancement of cancer and ab-
solute induction of cancer by radiation exposure involves all grades
of contributions of radiation to the total mechanism of the cancer.
The difference between the two, at least on a statistical basis, can-
not be fully appreciated without thorough determination of the
differences in total lifetime incidence, as well as in the age-adjusted
incidences between exposed and control groups.
4.10 Most of the available radiation information on man, and
even much of the available information on experimental animals,
is limited to a period after exposure that is considerably shorter
than the survival time of the groups studied. Therefore, the total
lifetime incidence of cancer can be estimated only by extrapolation
that involves assumptions concerning the future incidence of can-
cer in both the exposed and the control groups.
B. Considerations of Radiation Dose Threshold in General
4.11 It is the distribution of the individual dose thresholds for a
cancer in a population that determines the shape and intercept of a
dose-effect curve.
4.12 The term "threshold dose" has real meaning only in terms
of the radiation effect in an individual. If a population is being
considered, it has meaning only in terms of the radiation effect in
the most susceptible individual in that population; that is, the one
with the lowest dose threshold for the effect.
4.13 Theoretically, there is a finite probability that exposure to
the smallest quantity of ionizing radiation can cause a change in a
[p. 12]
cell—for example, a point mutation—that can contribute a part of
the complex mechanism of carcinogenesis in a tissue. Whether
this cellular change results in the induction of a cancer—that is, in
a "no-threshold" individual—depends on whether the balance of
the mechanism is provided by other means.
4.14 The more heterogeneous the population, with respect to
factors influencing individual susceptibility or dose threshold for a
radiation-induced cancer, the greater the probability of inclusion
of individuals in whom the smallest amounts of radiation exposure
could complete the required carcinogenic mechanism.
4.15 On logical or theoretical grounds, it is erroneous to assume
the existence of an absolute threshold dose for cancer of any kind
in all populations of any size or character. It is reasonable to
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GUIDELINES AND REPORTS 1309
assume that no absolute dose threshold exists for radiation induc-
tion of a cancer in a highly heterogeneous population of great or
unlimited size, even though the probability of a "no-threshold"
individual is very low, and even though some samples of the popu-
lation may show an observable or high threshold ("practical
threshold").
4.16 The "practical threshold" dose is the largest dose that has
been observed to be ineffective for causing an increased incidence
of effect (persons with the cancer of interest) in the samples of the
population that have been studied for this effect. The "practical
threshold" may differ between different samples of a population
according to differences in distribution of individual thresholds
(and ages) at the lower exposure levels.
4.17 Different tissues (for example, lung and bone), in addition
to their inherent differences in susceptibility to carcinogenesis (in-
cluding radiation carcinogenesis), may differ also in the extent to
which they are subjected to exogenous carcinogenic or damaging,
cancer-promoting agents and conditions. This factor, among oth-
ers, may result in differences in dose-effect relationships between
tissues, and should be considered in any attempt to relate one
tissue to another in this respect.
C. The Relevant Dose in Protracted Irradiation
4.18 With protracted, nonuniform exposure of tissue to alpha
particles, there is uncertainty, not only as to the tissue component-
dose that is relevant to carcinogenesis, but also as to the portion
of the total accumulated exposure that effectively contributed to
the induction of the cancer.
4.19 For each subject it takes a certain amount of time to ac-
cumulate the exposure (induction dose) required to ensure that
cancer will be induced and appear within his remaining life span.
After the induction dose has been accumulated, it takes some time
(latent period) for the cancer to appear. In protracted irradia-
tion, some of the total accumulated dose is "wasted" and irrelevant,
as far as the induction of a cancer is concerned. Some of the dose
in excess of the minimal induction dose conceivably may shorten
the latent period to some extent by substituting for other contrib-
uting factors that would have occurred eventually.
4.20 When the individuals of an exposed population receive the
protracted exposure at greatly different rates, a particular induc-
tion dose takes longer to accumulate at a low-dose rate than at a
high-dose rate. This longer time would be taken at the expense
of time available for the latent period even if dose rate did not
influence the required size of the induction dose. However, be-
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1310 LEGAL COMPILATION—RADIATION
cause the available evidence indicates that dose rate does influence
the carcinogenic effect, the required induction doses may be larger
at the lower dose rates and take still more time to accumulate.
D. Dose-Effect Relationships—General
4.21 For cancer induced by local exposure of the tissue of origin
of the cancer, there is, in general, an increase in incidence and a
reduced latent period with increasing dose within a certain dose
range. With further increasing dose, there may be a decline in the
rate of increase in incidence. This decline at high-dose levels is
represented first by a plateau in the dose-effect curve at peak in-
cidence levels, and then by a fall in the curve at still higher dose
levels. This fall in the curve at the highest dose levels has been
[p. 13]
attributed to degrees of tissue induction that eliminate cancer
induction in some persons. Fractionation of such large doses (in
the declining incidence range) can increase the incidence, pre-
sumably by reduction of the excessive tissue damage, but frac-
tionation of a dose in the range of rapidly rising incidence may
reduce the incidence.
4.22 For present purposes, several kinds of dose-response rela-
tionship should be considered. An observed dose-response rela-
tionship may be either linear or curvilinear (quadratic, sigmoid),
and in either case with or without a well-defined threshold
(practical).
4.23 A curvilinear relationship between dose and the probability
of cancer induction would be expected for cancers, such as lung
cancer, that depend greatly on localized tissue damage, which itself
is characterized by a curvilinear dose-effect relationship with
threshold. However, even under these circumstances, a linear
relationship is possible in a group in which there is a range of
individual thresholds distributed in a manner permitting a linear
relationship.
4.24 On the basis of the above considerations and the limitations
of dose-effect studies of radiation carcinogenesis at the lower dose
levels, it must be expected that even an observed dose-effect curve
with an apparently high- "practical" threshold may have in reality
a poorly denned threshold or none at all at lower dose levels, owing
to the presence of a small proportion of low-threshold individuals.
This lower threshold may be represented by a long, low tail of the
curve preceding the point of more rapid rise in the vicinity of the
"practical" threshold point. The length and position of this tail
and its relative practical importance would depend on the distribu-
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GUIDELINES AND KEPORTS 1311
tion of individual thresholds in one or another population, and this
distribution can be skewed in various ways by variable influences.
4.25 As a basis for protective measures, an arbitrary decision
may be made that the probable tail in this theoretical quasi-
threshold curve represents so few individuals as to be regarded as
negligible.
E. Dose-Effect Relationships—Assumptions
4.26 In the absence of data on cancer incidence related to low
doses or dose rates of radiation, the extent to which such exposure
has a carcinogenic effect and the shape of any dose-effect curve are
matters of speculation and hypothesis, regardless of the observed
shape of the dose-effect curve for larger or more intense doses.
This becomes more true as the dose range to which the observed
dose-effect relationship is limited or for which it is valid becomes
higher.
4.27 The establishment of a well-defined dose-effect curve on the
basis of a wide range of doses and dose rates is helpful in the arbi-
trary selection of a "practical" threshold or in the selection of a
curve and its shape for extrapolation to lower levels of exposures
for which there are no concrete data. Nevertheless, the relation-
ship at the low-dose or dose-rate levels is still hypothetical and
involves great assumptions concerning the dose-effect relationship,
the carcinogenic mechanisms operating, the dose-rate dependence,
the distribution of individual dose thresholds, and the latent period
for the manifestation of the effect. When relationships (often
based on the linear hypothesis) are used for purposes of radiation
protection it is necessary to discourage the acceptance of such
procedures as scientific dogma. There should be explicit qualifica-
tion of the scientific validity of the arbitrary assumptions involved.
4.28 In the present state of data on man, which involve non-
uniform exposure of tissue and individuals of heterogeneous
groups, often with differences in dose rates, it is necessary for a
particular risk estimate to select a single value of a quantity that
characterizes the exposure of a group or subgroup, even though
such a value may be of limited significance or accuracy. Mean
accumulated tissue dose (or exposure) for the individual and for
groups of individuals is the only criterion that can be used prac-
tically to estimate risks of cancer in such populations until ade-
quate knowledge of more relevant criteria becomes available.
[p. 14]
Furthermore, when the dose rate is not uniform and its influence
in the exposed group is not known, it must be ignored until more
adequate data are available. The linear hypothesis is the only one
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1312 LEGAL COMPILATION—RADIATION
that normally permits the use of mean dose or exposure as the
significant dose factor under conditions of nonuniform exposure
and exposure rate in an individual and among individuals, and that
permits the neglecting of dose rate. The use of a nonlinear dose-
effect relationship requires consideration of the individual dose
and dose rate, and the distribution of doses and dose rates for pur-
poses of estimating risk or setting dose limits.
4.29 If the slope (rate of increase in incidence with increasing
dose) to be used for linear extrapolation to low-dose levels is
obtained from observed dose-effect data that happen to be in the
most rapidly rising segment of the total curve, it is likely that the
risk per unit dose at the low-dose levels will represent an upper
limit. However, if the slope for linear extrapolation is obtained
from observed data that happen to be in the high-dose range of
the dose-effect curve, where the doses exceed the maximum effec-
tive induction dose (plateau of constant incidence with increasing
dose) or where the doses are associated with a decline below the
peak incidence found at lower doses, the risk per unit dose at lower
dose levels may be underestimated. In any case, such estimates of
risk are reliable only in the range of observed dose-effect data from
which they were validly derived and only under the associated con-
ditions of the exposure and the exposed.
4.30 The presently available data on lung cancer and exposure
to radon daughter products (expressed as Cumulative Working
Level Months) in uranium miners do not permit reliable quan-
titative description of the exposure-effect relationship, or even
identification of the general shape of the curve, because of: (a)
uncertainties as to exposure and exposure rate, (b) limitations on
numbers and followup time, and (c) inability to separate out the
effects of combined factors, such as cumulative exposure, exposure
rate, age at exposure, minimal and exposure-related latent periods,
relevant induction exposure, and exposure to other agents. There-
fore, it is not possible at present to select from these data a reason-
ably reliable or valid exposure-effect relationship for extrapolation
to low-exposure levels on the basis of an arbitrary assumption of a
hypothesis, linear or otherwise.
[P. 15]
SECTION V. PATHOLOGY
5.1 The most noteworthy feature of the pathology of lung cancer
in the uranium miners of the study group is the great preponder-
ance of the small-cell undifferentiated tumors in the higher expo-
sure categories, as reported by Saccomanno and others (24)',
details are tabulated in reference (2) pp. 1062-1067. With esti-
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GUIDELINES AND REPORTS 1313
mated exposures of less than 360 WLM, two of 11 neoplasms were
of the undifferentiated type. This cannot be stated to be in excess
of the expected incidence of this tumor type. With estimated
exposure levels of 360 WLM or more, small-cell undifferentiated
tumors accounted for 60 to 70 percent, whereas tumors of this
type usually constitute 20 to 30 percent of all malignant bronch-
ogenic neoplasms in males.
5.2 The small cell undifferentiated type is known to have
predominated in the lung cancers among the cobalt miners of
Schneeberg and Joachimstahl; in fact, it is understandable from
morphologic similarities that these tumors were first considered
to be lymphosarcomas and not identified as carcinomas until the
late 1920's (25). It must be recognized, with the methods cur-
rently available, that it is not possible to determine whether any
given lung cancer was caused by ionizing radiation. Thus, the
etiologic role of ionizing radiation in the genesis of lung cancer of
uranium miners at high exposure must be accepted as a high
probability, on the basis primarily of epidemiologic evidence with
suggestive support from histologic evidence. Among the miners
of the Schneeberg district, it was not until after 1928 that evidence
was presented that radioactivity of the ores was the principal
etiologic factor (Sikil, 27). Hueper (28) has summarized data
relating ionizing radiation to the pathogenesis of pulmonary tu-
mors. Koelsch (29) reported, of 469 deaths among the miners of
this district from 1875 to 1912, that 276 were due to pulmonary
carcinoma. This extremely high mortality from cancer of the
lung, first noted by Harting and Hesse (30) in 1879, suggests the
existence of a special environmental factor or factors different
from those of the general experience of the ordinary miner.
5.3 It has been established that the American uranium miners
likewise have a mortality from lung cancer clearly in excess of that
reported among other miners in the United States (31). Ep-
idemiologic evidence of the etiologic role of radiation, rather than
other possible factors, is summarized by Wagoner (32) and by
Cooper (33), and is further discussed in relation to presumed ex-
posure in section VI of this report.
5.4 The question of the possible potentiating or cocarcinogenic
action of two or more agents in the development of pulmonary
carcinoma may be raised. An excellent example in animal pathol-
ogy is represented by the experiments of Kotin and Wiseley (34.).
They found that squamous metaplasia and invasive and metas-
tasizing squamous carcinoma developed in C-57 black mice only if
the animals were exposed to both mouse-adapted influenza virus
and an aerosol of ozonized gasoline ("artificial smog"). Only
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1314 LEGAL COMPILATION—RADIATION
acinar atypical proliferation was observed if either agent was used
alone. This study has special significance, in that spontaneous
squamous cancers are exceedingly rare in rodents, and a cocarcino-
genic effect of viral and chemical agents was demonstrated.
[p. 16]
5.5 In man, the relation and interstitial pneumonia, honeycomb-
ing, and atypical epithelial proliferation to cancer of the lung has
been studied in considerable detail (35). It is of note that all the
patients in the honeycombing-carcinoma group were male, and also
that all the patients from whom a smoking history had been ob-
tained were cigarette smokers. In the case of the cancer patients
without a background of honeycombing, at least 16 percent were
nonsmokers. It is known that the honeycombing itself is not
necessarily associated with smoking. These observations suggest
the possibility of some potentiating effect that is related to the
combination of widespread pulmonary scarring with associated
epithelial hyperplasia, and exposure to cigarette smoke. Selikoff,
Hammond, and Churg (36) have recently reported a similar re-
lationship between exposure to asbestos, smoking, and neoplasia.
Of 87 nonsmokers in a group of 370 asbestos workers, none died
of bronchogenic carcinoma during the study period, but of 283
of the workmen with a history of regular cigarette smoking, 24
died of bronchogenic carcinoma, although only three were expected
to die of this disease.
5.6 There is evidence that pulmonary fibrosis and atypical pro-
liferation are relatively frequent in uranium miners (as in other
miners) in comparison with the general population (32). Expo-
sure to ionizing radiation superimposed on such chronic pulmonary
disease might have a potentiating effect in relation to development
of bronchogenic carcinoma. This general relationship requires
further study, and specifically the nature and extent of noncan-
cerous (possibly precancerous?) pulmonary disease in the miners
should be investigated in a systematic and detailed manner.
5.7 Also to be considered is the possible cocarcinogenic action of
smoking and exposure to radon and its daughters. This hypothesis
is supported primarily by epidemiologic evidence presented in
section VI. It is evident, however, that there is a large excess of
respiratory tract cancers among uranium miners, even when ac-
count has been taken of variability associated with age, smoking,
and other factors (37). As emphasized by Kreyberg (38), ep-
idermoid carcinomas, rather than small-cell undifferentiated neo-
plasms, predominate among cigarette smokers in general.
5.8 A number of features of the natural history of the respira-
tory tract neoplasms associated with uranium mining may have
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GUIDELINES AND REPORTS 1315
relevance to pathogenesis, as well as etiology. Most of the tumors
in these miners appear to originate in major bronchi, as is typical
of the dominant small-cell undifferentiated type. The idea that
such tumors are derived from reserve cells that are relatively
deeply placed in the epithelial lining (39) is a hypothesis without
firm foundation, and it must be admitted that the histogenesis is
essentially unknown. Localization in the large bronchi may be
related to the occurrence there of a cell type that is particularly
sensitive to some factor associated with uranium mining, or pos-
sibly to maximal effective concentration of a responsible factor or
factors in this distribution. The complexity and unresolved state
of the problems relating ionizing radiation exposure to tissue dos-
age are considered particularly in section III of this report.
5.9 Cytologic examination of sputum has been suggested as a
method of surveillance whereby precancerous lesions might be
detected in uranium miners, as in other "high-risk" groups (40).
Further exploration of this method under carefully controlled
conditions, using the "blind" reading technique in correlation with
long-term followup of patients, is needed to establish its validity.
5.10 Some conclusions that may be drawn at this time are:
(a) The reported dominance of small-cell undifferentiated bronchogenic
carcinomas among uranium miners, especially in consideration of epidemio-
logic data, strongly suggests that radiation may be the most important de-
termining factor in the excessive prevalence of lung cancer among uranium
miners at the higher exposure levels. Reexamination of the pathologic
material by a second experienced panel of experts is in progress and should
[P- 17]
provide valuable information and interpretation (3J^A).
(b) Granting the strong possibility of the cocarcinogenic effect of cigarette
smoking, and perhaps also fibrosing pulmonary disease, the preeminence of
the radiation factor is likely for the same reason; that is, predominance of
the small-cell type.
(c) The following subjects are worthy of investigation as problems in
pathology, as well as epidemiology:
(1) the nature of fibrosing pulmonary disease in these miners, with
attention to intensity and duration of exposure in the mines, and
(2) sputum cytology as a clue to the development of precancerous
lesions in the lung, as well as to diagnosis of manifest cancer.
(d) There is also a need for accurate information regarding the radio-
biology of the lung exposed to inhaled radioactive gases of particles in rela-
tion to:
(1) the effects of the radioactive materials as a function of the physi-
cal decay process;
(2) pulmonary dynamics in terms of the transport or persistence of
the radioactive materials in the various possible distributions within the
lung;and
(3) the cellular response of the lung itself.
[p. 18]
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1316 LEGAL COMPILATION—RADIATION
SECTION VI. EPIDEMIOLOGY
6.1 Epidemiologic data on man must constitute the final court of
appeal on questions of risks to man associated with environmental
exposures. Despite uncertainties in dose categorization for ura-
nium miners and despite the relatively small populations involved,
epidemiologic data have been developed that have considerable
bearing on two issues of primary concern:
(a) Is there a cause-effect relationship at 100 to 400 CWLM?
(b) Is there a synergistic effect on cigarette smoking on the production of
lung cancer in uranium miners?
A. The Question of a Cause-Effect Relationship at 100 to 400
CWLM
6.2 We should separate this issue into two questions:
(a) Is there a statistical association between lung cancer and exposures at
100 to 400 CWLM?
(b) If so, is radiation the principal causative agent?
6.3 There have been several epidemiologic studies of lung cancer
and other causes of death in uranium miners in Europe, in hard-
rock metal miners in the United States and elsewhere, and in coal
miners; however, none of these studies can be said to cast any light
on the specific question posed here. In regard to the hard-rock
metal miners, the variety of the associated exposures, which in-
clude radon, makes it difficult to assign causal roles to any par-
ticular item or combination of items. In regard to the coal miners,
the data from different countries are conflicting and information
on radon and other exposures is lacking. The U.S. Public Health
Service study of U.S. uranium miners is the only study in which
information on levels of exposure makes it at all feasible to at-
tempt a description of the relationship between lung cancer rates
and cumulative exposure to radon daughter products. It is also
the only relevant study in which histories of cigarette smoking
have been obtained. Unless otherwise specified, the data quoted
in the following paragraphs are taken from the most recent report
of the U.S.P.H.S. study (41).
6.4 In the U.S. Public Health Service study the data for white
underground uranium miners who died from January 1950 through
September 1967 show a statistically significant excess of deaths
ascribed to lung cancer in each of the three categories of estimated
cumulated exposures under 840 CWLM (ref. (41), also table 1 in
app.). For all exposures less than 840 CWLM, 7.2 deaths were
expected, on the basis of the death rates for the general white male
population of the mining area, and 25 were observed. This excess
is most unlikely to be due to chance (p < 0.01). In the exposure
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GUIDELINES AND REPORTS 1317
category of 120 to 359 CWLM, 2.4 deaths were expected and 10
were observed (p < 0.01).
6.5 For the three exposure categories over 840 CWLM, the
most recent data continue to show the consistent and marked in-
crease in lung cancer risk with increasing exposure that was ob-
served earlier. This provides strong evidence for the hypothesis
that radiation is a major causal factor in lung cancer at these ex-
[p. 19]
posure levels.
6.6 A trend toward increasing risk with increasing exposure is
not seen in the three exposure categories under 840 CWLM; in-
deed, the relative excess of observed over expected is lowest in the
360 to 839 CWLM category. There are, however, several reasons
why it is difficult to demonstrate the presence or absence of a trend
at these levels:
(a) Numbers are small and random fluctuations may be important. Vari-
ations on only one or two deaths in any of these categories would produce
changes in their relative positions on a scale of risk.
(b) Measurements of exposure levels in the mines and estimates of the
cumulative individual exposures may not be sufficiently accurate to dis-
criminate among the three categories.
(c) Prior experience in hard-rock mines also involving exposure to radon
daughters (that included in the computation of CWLM) has naturally be-
come of relatively greater significance when the exposure from uranium
mining is small. Thus, seven of the eight lung cancer cases in the < 120
CWLM category had prior hard-rock mining experience of between 7 and 30
years. In the two other categories (120 to 359 CWLM and 360 to 839
CWLM), however, one half of the lung cancer patients had prior hard-rock
mining experience of 2 years or less. If attention is restricted to miners
without prior hard-rock experience, there were in the three exposure cate-
gories under 840 CWLM, 3.1 expected lung cancer deaths and six observed.
Among miners with less than 10 years of prior hard-rock experience, there
were, in the same exposure categories, 1.6 expected and eight observed lung
cancer deaths. The impression is strong that prior hard-rock mining experi-
ence complicates the -dose-response relationship in the lower exposure cate-
gories, but it is unlikely to explain the overall excess of lung cancer cases in
these categories.
6.7 Uranium miners appear to be somewhat heavier smokers
than the general male population of the United States, but not
sufficiently so to introduce substantial changes in the expected
number of lung cancer cases. Smoking habits of the men in the
low-exposure categories are similar to those in the high-exposure
categories, and the excess cases in the low-exposure categories
cannot be explained by any peculiarity of smoking patterns.
6.8 The question of accuracy of statement of cause of death on
death certificates has been carefully reviewed by the U.S. Public
Health Service. The data quoted above refer to tables that include
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1318 LEGAL COMPILATION—RADIATION
only cases in which lung cancer is certified as the underlying cause
of death. The restriction to cases in which the cancer was certified
as the underlying cause was imposed because this is the basis for
the cause-specific mortality rates in the general population from
which expected numbers were derived. Not all the cases included
in the latest mortality analysis have yet been reviewed histologic-
ally; however, in a review by the U.S. Public Health Service of 34
cases included in an earlier analysis based on the same criteria,
28 cases were confirmed as primary lung cancer, and only two
were considered not to be primary lung cancer. Available mate-
rial was inadequate for diagnosis in the other four cases (ref. (2),
p. 1265). Several cases of lung cancer in addition to those used
in the mortality analysis are known in the study population. The
estimates of risk given in the U.S. Public Health Service data are
minimal estimates, in this respect.
6.9 The biggest source of uncertainty in interpreting the data
from the U.S. Public Health Service study, particularly in the low-
exposure categories, is the accuracy of allocation to categories of
exposure. This problem has been referred to earlier in the report.
As time passes, more and more experience will be gained during
periods when exposure levels have been more accurately recorded,
and, correspondingly, interpretations will be more firmly based.
Meanwhile, the possibility of errors in exposure estimates does not
warrant the rejection of inferences from what, taken at face value,
is a rather impressive accumulation of cases in the low exposure
[p. 20]
categories. The errors involved in omission of exposures attribu-
table to prior hard-rock mining have been referred to in paragraph
6.5. With respect to errors in assignment of exposures during
the uranium mining experience, it does not appear that there has
been any differential bias in assignment to exposure categories of
miners who subsequently developed lung cancer.
6.10 The question of whether the increased risk seen at approx-
imately 100 to 400 CWLM is due to exposure to radon daughter
products is complex. In favor of the hypothesis that radon daugh-
ters are a contributing factor is the evidence that these grants are
primarily responsible for the lung cancer observed at high-expo-
sure levels. On the principle of parsimony, in this instance by
assuming that the same relationship holds for the lower exposure
levels, it seems reasonable to attribute at least part of the observed
increase at 100 to 400 CWLM to the radon daughters. However,
the lack of demonstrated increase in risk with increasing exposure
at the lower exposure levels calls for caution in accepting this
hypothesis. The possibility that other factors associated with ura-
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GUIDELINES AND REPORTS 1319
mum mining, or with mining in general, account for all or part of
the increase cannot be excluded.
6.11 It should be noted that the data are compatible with a va-
riety of dose-response curves, and theoretical dose-response rela-
tionships cannot be used to argue for or against causal association
in the 100 to 400 CWLM exposure category. The observations do
not support the hypothesis of a threshold in this range of exposure
or higher.
6.12 In summary, it is concluded that there is a statistically
significant increase in the lung cancer risk for miners with 100 to
400 CWLM exposure that cannot be explained by any known arti-
fact of the data. The question of whether radiation exposures of
this level induce cancer must still be considered open. In the
opinion of the committee, the hypothesis is favored that radiation
exposure at least contributed to the excess lung cancer observed in
the miners in the approximately 100 to 400 CWLM category. This
conclusion may require revision when more definitive data become
available on such matters as:
(a) the measurement of CWLM from all mining experiences, not only that
attributable to exposure in uranium mines;
(b) histologic confirmation of the types of lung cancer seen at the various
levels of exposure;
(c) the identification of other, possibly relevant exposures experienced by
uranium miners; and
(d) the use of various comparison groups, including miners with minimal
radiation exposure.
B. Synergistic Effect of Cigarette Smoking and Uraninm Mining
6.13 Although available data are relatively sparse, there is a
distinct suggestion in them that cigarette smokers among the
uranium miners are particularly susceptible to lung cancer. Two
pieces of evidence support this suggestion.
6.14 Among the white underground miners in the U.S. Public
Health Service study group, 78 percent were smokers and 22 per-
cent nonsmokers. Sixty of the 62 deaths from lung cancer to date
have occurred in smokers. The number of lung cancer deaths ex-
pected on the basis of general population rates was 10.1. Given a
relative risk of 10 for smokers vis-a-vis nonsmokers, these ex-
pected deaths would have broken down as 0.3 in nonsmokers and
9.8 in smokers. The deaths in excess of 10.1—that is, 51.9 deaths
—are the deaths attributable to uranium mining. If these deaths
occurred independently of smoking, we would expect to find them
distributed by smoking habits in the same proportion as the mining
population; that is, 22 percent of them, or 11.4 deaths, would have
-------
1320 LEGAL COMPILATION—RADIATION
been in nonsmokers. The occurrence of only two deaths in non-
smokers is not likely to be due to chance (p < 0.01).
6.15 Among 761 nonwhite, mostly American Indian, under-
ground uranium miners in the U.S. Public Health Service study,
[P. 21]
1.3 deaths from lung cancer were expected and only two were
observed, one in a smoker. Although there are alternative ex-
planations, this observation is explicable in terms of a synergistic
effect of cigarette smoking and uranium mining, inasmuch as 82
percent of the person-years at risk of the nonwhite group were
referable to nonsmokers.
[P. 22]
SECTION VII. CONCLUSIONS
7.1 At this time, the empiric approach using epidemiologic data
represents the best basis for establishment of guidance for expo-
sure of uranium miners. This approach at present necessarily
assumes that the cumulated exposure to radon and its daughter
products, based on measurement or estimate of mine air and ex-
pressed in Working Level Months (WLM), bears a constant re-
lationship to the radiation dose to the critical tissue.
7.2 Uncertainties in regard to estimations of Working Levels
and of absorbed dose to tissue can be considered in two categories:
(a) physical measurements of mine air, and (b) physical and
physiologic processes in the lung.
7.3 In regard to the physical measurements, it is considered that
exposure values assigned to the period before 1956 are highly un-
reliable, being based almost entirely on estimates, rather than
measurements of concentrations. The sampling frequency there-
after increased with time, but even so some of the 1956-1960
values may be in error by an order of magnitude. Values for the
period after 1960 are the most reliable, but nevertheless many of
the Working Level values reported are only estimates, no measure-
ments having been made. It is unfortunate that the early values
are so unreliable, because the latent period for tumor induction
makes these early values of exposure and dose particularly im-
portant.
7.4 Improvement in physical measurements may soon be ex-
pected. Assuming that other problems can be overcome, we may
expect that measurements, in combination with information about
the worker's activity, respiratory physiology, and associated en-
vironmental factors can be used to provide a reasonable estimate
of exposure or body burden.
-------
GUIDELINES AND REPORTS 1321
7.5 Although our present capabilities for estimating the actual
dose-equivalent to lung tissue cannot be used for guidance pur-
poses, studies of this problem should be continued and expanded to
provide future understanding. The primary information needs
concern: (a) the proportions of free ions, (b) more basic data
with which to improve lung models, (c) the critical tissue, and
(d) the quality factor for the radiation.
7.6 The presently available data on exposure to radon and its
daughter products and the mortality rate from lung cancer do not
permit reliable quantitative description of the exposure-effect re-
lationship or identification of the general shape of the curve. The
primary deficiencies in the data are: (a) uncertainties as to ex-
posure and exposure rate, (b) limitations in number and followup
time, and (c) unknown interrelationships of combined factors,
such as cumulated exposure, exposure rate, age at exposure, min-
imal and exposure-related latent periods, relevant induction expo-
sure, "wasted" exposure, and cancer-promoting effects of other
agents and conditions. These deficiencies could be remedied at
least in part by epidemiologic studies of properly chosen com-
parison groups.
7.7 The reported dominance of small-cell undifferentiated
bronchogenic carcinomas among uranium miners exposed at the
higher levels suggest the importance of the radiation factor,
granted the strong possibility of the cocarcinogenic effect of ciga-
rette smoking and perhaps also of fibrosing pulmonary disease.
[p. 23]
7.8 Recognizing the unreliability of present data on uranium
miners, but accepting them at face value with a realization that
decisions must be taken before completely adequate scientific ev-
idence is available, the committee draws the following conclusions:
(a) There appears to be a causal association between lung cancer and
exposures of approximately 1,000 CWLM and higher.
(b) There is a statistically significant increase in the lung cancer risk for
miners with approximately 100 to 400 CWLM exposure that cannot be ex-
plained by any known artifact of the data.
(c) The hypothesis is favored, pending more definitive data, that radia-
tion exposure at least contributed to the excess lung cancer observed in the
miners in the 100 to 400 CWLM category.
7.9 Existing data strongly suggest that cigarette smokers
among the uranium miners are particularly susceptible to lung
cancer.
[p. 24]
-------
1322 LEGAL COMPILATION—RADIATION
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ground Uranium Miners of Airborne Radon-Daughter Products, Report of
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(4) LOYSEN, P. Errors in Measurement of Working Level. Presented at
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suchungen zur Biologischen Wirkung des Radons und seiner Folgeprodukte.
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(6) GEORGE, A. C., and A. J. BRESLIN. Deposition of natural radon daugh-
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(9) SCHIAGER, K, J., A. H. DAHL, R. J. REECE, and P. W. JACOB. Radon
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(10) SHAPIRO, J. An Evaluation of the Pulmonary Radiation Dosage from
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(11) BRESLAN, A. Personal communication, May 1968.
(12) CHAMBERLAIN, A. C. and E. D. DYSON. The dose to the trachea and
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[P. 25]
(13) DAHL, A. H., K. J. SCHIAGER, R. J. REECE, and P. W. JACOB, Radon
Progeny Inhalation Study, as Applicable to Uranium Mining Operation.
Second Annual Report on Atomic Energy Commission Contract AT
(11-1)-1500. Colorado State University, Fort Collins, Colo. (1966).
(14) REITER, R. and W. CARNUTH. Das Partikelspektrum eines mit Radon-
folgeprodukten Beladenen Aerosols. Naturwissenschaften 2:40-41 (1967).
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GUIDELINES AND REPORTS 1323
Committee II of the International Commission on Radiological Protection.
Health Phys 12:173-207 (February 1966).
(16) ALTSHULER, B., N. NELSON, and M. KUSCHNER. Estimation of lung
tissue dose from the inhalation of radon and daughters. Health Phys
10:1137-1161 (1964).
(17) JACOBI, W. The dose to the human respiratory tract by inhalation of
short-lived -22 Rn and 2-2 Rn-decay products. Health Phys 10:1163-1175
(1964).
(18) THOMAS, J. A method for calculation of the absorbed dose to the epithe-
lium of the respiratory tract after inhalation of daughter products of
radon. Ann Occup Hyg 7:271-284 (1964).
(19) HAQUE, A. K. and A. J. COLLINS. Radiation dose to the respiratory
system due to radon and its daughter products. Health Phys 13:431-443
(1967).
(20) MORROW, P. E., F. R. GIBB, and K. M. GAZIOGLU. A study of particulate
clearance from the human lungs. Amer Rev Resp Dis 96:1209-1221
(1967).
(21) MORKEN, D. A., and J. K. SCOTT. The Effects on Mice of Continual
Exposure to Radon and its Decay Products on Dust. University of Roches-
ter, Atomic Energy Commission Project Report No. UR-669 (1966).
(22) BLACK, S. C., V. E. ARCHER, W. C. DIXON, and G. SACCOMANNO. Corre-
lation of radiation exposure and lead-210 in uranium miners. Health Phys
14:81-93 (1968).
(23) CASARETT, G. W. Experimental radiation carcinogenesis. Progr Exp
Tumor Res 7:49-82 (1965).
(24) SACCOMANNO, G., V. E. ARCHER, R. P. SAUNDERS, L. A. JAMES, and P. A.
BECKLER. Lung cancer of uranium miners on the Colorado plateau.
Health Phys 10:1195-1201 (1964).
(25) ROSTOSKI, SAUPE, and SCHMORL. Die Bergkrankheit der Erzbergleute
Schneeberg in Sachsen ("Schneeberger Lungenkrebs"). Z Krebsforsch
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(26) LoWY, J. Uber die Joachimsthaler Bergkrankheit (Vorlaufige Mit-
teilung). Med Klin 25:141-142 (1929).
(27) SIKL, H. Uber den Lungenkrebs der Bergleute in Joachimstahl
(Tschechoslowakei). Z Krebsforsch 32:609-613 (1930).
(28) HUEPER, W. C. Recent developments in environmental cancer. Arch
Path 58:360-399; 475-523; 645-682 (1954).
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(1938).
(30) HARTING, F. H. and W. HESSE. Der Lungenkrebs, die Bergkrankheit
in den Schneeberger Gruben. Viertelj Gerichtl Med Off en Sanitats 30:296-
309; 31:102-132; 313-337 (1879).
(31) ENTERLINE P. E. Mortality rates among coal miners. Amer J Public
Health 54:758-768 (1964).
(32) WAGONER, J. K., V. E., ARCHER, F. E. LUNDIN, JR., D. A. HOLADAY,
and J. W. LLOYD. Radiation as the cause of lung cancer among uranium
miners. New Eng J Med 273:181-188 (1965).
(33) COOPER, W. C. Uranium mining and lung cancer. J Occup Med
10:82-88 (1968).
[p. 26]
(34) KOTIN, P. and D. V. WISELEY. Production of lung cancer in mice by
inhalation exposure to influenza virus and aerosols of hydrocarbons. Prog
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1324 LEGAL COMPILATION—RADIATION
Exp Tumor Res 3:186-215 (1963).
(34A) YESNER, R. B. GERSTL, and O. AUERBACK. Histologic types of bron-
chogenic carcinoma in uranium miners (to be published).
(35) MEYER, E. C. and A. A. LIEBOW. Relationship of interstital pneumonia
honeycombing and atypical epithelial proliferation to cancer of the lung.
Cancer 18:322-351 (1965).
(36) SELIKOFF, I. J., E. C. HAMMOND, and J. CHURG. Asbestos exposure,
smoking, and neoplasia. JAMA 204:106-112 (1968).
(37) WAGONER, J. K., V. E! ARCHER, B. E. CARROLL, D. A. HOLADAY, and
P. A. LAWRENCE. Cancer mortality patterns among U.S. uranium miners
and millers, 1950 through 1962. J Nat Cancer Inst 32:787-801 (1964).
(38) KREYBERG, L. Histological Lung Cancer Types: A Morphological and
Biological Correlation. Norwegian Universities Press, Oslo (1962) 92 pp.
(39) HALPERT, B. and B. PEARSON. The cellular structure of carcinoma of
the lung. Amer J. Cancer 40:213-218 (1940).
(40) SACCOMANNO, G., R. P. SAUNDERS, V. E. ARCHER, 0. AUERBACH, M.
KUSCHNER, and P. A. BECKLER. Cancer of the lung: the cytology of
sputum prior to the development of carcinoma. Acta Cytol 9:413-423
(1965).
(41) LXJNDIN, F. E., JR., V. E. ARCHER, D. A. HOLADAY, J. W. LLOYD, and
E. M. SMITH. Mortality of Uranium Miners in Relation to Radiation Ex-
posure (to be published).
[p. 27]
4.2c IMPLICATION TO MAN OF IRRADIATION BY
INTERNALLY DEPOSITED STRONTIUM-89, STRONTIUM-90,
AND CESIUM-137, REPORT OF AN ADVISORY COMMITTEE
FROM THE DIVISION OF MEDICAL SCIENCES: NATIONAL
ACADEMY OF SCIENCES—NATIONAL RESEARCH
COUNCIL, FEDERAL RADIATION COUNCIL,
DECEMBER 1964.
FOREWORD
In its continuing assessment of the health implications of expo-
sure of man to ionizing radiation, the Federal Radiation Council
invited the National Academy of Sciences to aid it in reviewing
various aspects of the field. An Advisory Committee to the Fed-
eral Radiation Council was duly appointed by the Academy within
the Division of Medical Sciences of the National Research Council.
The first request of the Federal Radiation Council was for a
summary statement concerning the effects to be expected in man
from irradiation by internally deposited strontium-89, strontium-
90, and cesium-137, with reference to effects that might occur at
dose levels of the order of 25 rads or less. The report which fol-
lows was prepared by the Advisory Committee. It surveys the
possible effects of these nuclides in man in light of their particular
metabolic properties and in relation to the known effects of ir-
-------
GUIDELINES AND REPORTS
1325
radiation from other internally deposited radioelements and from
external sources.
The views of the committee are based on evidence documented
in the scientific literature and reviewed extensively in cited reports
by the National Academy of Sciences Committees on the Biological
Effects of Atomic Radiation, by the United Nations Scientific Com-
mittee on the Effects of Atomic Radiation, and by the Medical
Research Council Committee on the Hazards to Man of Nuclear
and Allied Radiations. No attempt has been made to discuss the
evidence fully again at this time. Consequently, the presented
material is submitted as a working paper for the use of the Federal
Radiation Council.
Arthur C. Upton, Chairman
Brian MacMahon
Joseph E. Rail
W. L. Russell
Eugene L. Saenger
Shields Warren
31 December 1964
[p. iii]
Howard L. Andrews
Victor P. Bond
Cyril L. Comar
James F. Crow
Samuel P. Hicks
CONTENTS
Foreword iii
Section I. Introduction 1
Section II. Cesium 3
Metabolism 3
Dosimetry 5
Section III. Strontium-89 and Strontium-90 6
Metabolism 6
Dosimetry 10
Section IV. Genetic Effects 12
Section V. Somatic Effects 16
Effects on Embryological Development 16
Prenatal X-ray Exposure and Childhood Cancer 16
Effects of Postnatal Exposure 18
Induction of Leukemia 18
Induction of Bone Tumors 20
Tumors of the Thyroid 22
Other Neoplasms 22
Other Somatic Effects in Children and Adults 23
Summary and Conclusions 24
Eeferences 27
[p. v]
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1326 LEGAL COMPILATION—RADIATION
SECTION I
INTRODUCTION
1.1 All ionizing radiations can cause the same types of biological
effects, the probability of any given effect depending on the con-
ditions of exposure. Consequently, the hazards of irradiation from
radioactive strontium and cesium, as from any internally deposited
radionuclide, depend on the distribution of the elements in the
body, their retention, and their radioactive decay. These proper-
ties, in turn, depend on the chemical behavior of strontium and
cesium in the forms in which they are encountered and on the
physical characteristics of their several isotopes.
1.2 Cesium-137 is an alkali metal chemically similar to potas-
sium, which it resembles metabolically. As such, it is distributed
relatively uniformly throughout the body and is excreted largely
within a period of months. Because of the distribution of cesium-
137 in the body, the radiation from this isotope resembles whole
body irradiation. It is a beta-emitter, decaying with a physical
half-life of 29.7 years, to form barium-137m, which in turn decays
almost at once with emission of gamma rays.
1.3 Strontium is an alkaline earth, similar to calcium and ra-
dium in its metabolism by the body. As such, it has a predilection
for bone, into which it becomes tightly bound and from which it is
excreted slowly over a period of years. Because the radiation
from strontium-89 and strontium-90 is localized primarily in bone
and to a lesser extent in bone marrow, the nuclides give rise to
exposure principally of these tissues, although they may irradiate
other parts of the body in the process of uptake and excretion.
Both nuclides are beta-emitters, with physical half-lives of 50.5
days and 27.7 years, respectively. On decay strontium-90 gives
rise to a beta-emitting daughter element, yttrium-90, which has a
physical half-life of about 2.5 days.
1.4 Principles for evaluating the health implications of radio-
nuclides, as summarized in earlier reports by the Federal Radia-
tion Council (No. 3, 1962; No. 5, 1964), have laid stress on per-
manent somatic and genetic effects, which may be induced by
low-level irradiation in the absence of immediate or obvious man-
ifestations of radiation injury. In the report that follows, these
principles will be applied primarily to a consideration of the health
implications of the uptake of strontium-89, strontium-90, and
cesium-137 by a small fraction of the population on a short-term
basis (i.e., for a period of days to months).
1.5 The evaluation of the effects of these nuclides involves many
uncertainties and depends heavily on extrapolation from studies
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GUIDELINES AND REPORTS 1327
with experimental animals, since observations on the effects of
radioactive strontium and cesium in man are fragmentary.
1.6 With whole body exposure, such as from radioactive cesium,
the possible effects of chief concern are genetic damage, leukemia,
and other neoplasms. Other effects to be considered, however,
include injury to the developing fetus, life-shortening, and retarda-
tion of growth.
[p. 1]
1.7 With localized irradiation of the bone and bone marrow, as
from radioactive strontium, the principal effects to be considered
are induction of bone tumors and leukemia, as well as disturbances
in the growth and development of skeletal parts and teeth.
1.8 Although radionuclides of cesium and strontium are con-
sidered separately in this report, it is recognized that they will be
encountered together in most instances of contamination.
[P. 2]
SECTION II
CESIUM
Metabolism
2.1 Cesium exists as stable cesium-133 in mammals in a con-
centration of about 10~4 Digrams per gram of wet tissue. Cesium-
137 is the only isotope of cesium that makes an appreciable con-
tribution to the radiation dose to man. Cesium-134 has been
detected in man but only in the presence of a much greater activity
of the longer lived cesium-137.
2.2 Cesium-137 is a fission product which enters the human
food chain primarily by deposition on foliage that is later con-
sumed by domestic animals. The amount of cesium-137 that enters
the human food chain appears to increase with the amount of rain-
fall in the area where dairy cattle graze (Rickard et al., 1962).
The major portion of the cesium-137 burden in the United States
population conies from the consumption of milk and milk products;
meat products are the second most important source (Anderson,
E. C. et al., 1957). A relatively high cesium-137 burden has been
found in Swedish Lapps (Liden, 1962), resulting from the con-
sumption of reindeer meat which, in turn, derived its cesium from
a lichen having a high affinity for extracting this element from its
environment. A similar food chain appears to account for the
relatively high cesium-137 levels found in the Northern Alaskan
Eskimos (Hanson et al., 1964). Elevated levels have been re-
-------
1328 LEGAL COMPILATION—RADIATION
ported in other populations living in the far north (United Nations
Scientific Committee on the Effects of Atomic Radiation, 1964).
2.3 Cesium-137 has been detected in edible marine organisms,
including fish, but the concentration factors are too small to make
an important contribution to the total human intake.
2.4 Cesium-137 has also been observed in human milk (Aarkrog,
1962). The cesium-potassium ratios in human milk range up to
about twice the corresponding ratios in the mother's diet, indicat-
ing that the mammary gland tends to concentrate cesium in the
milk relative to potassium. The cesium-potassium ratios in human
milk parallel but are slightly higher than the corresponding ratios
in cow's milk from neighboring areas. The absolute cesium-137
content per unit volume is lower in human milk than in cow's milk,
however, because the latter contains about three times as much
potassium as the former.
2.5 Measurements in animals (Moore and Comar, 1963) show
that a developing fetus comes rapidly into cesium-137 equilibrium
with cesium ingested by the mother. In a small number of ob-
served cases the concentration of cesium in children shortly after
birth was essentially the same as that in the mother (Bengtason
etal., 1964).
2.6 Most cesium salts are quite soluble and hence are rapidly
and completely absorbed, with little dependence upon the route of
administration. Tracer studies in the cow show that about 13
percent of a single cesium-137 dose appears in the milk over a 30-
day period (Hood and Comar, 1953). In a woman essentially in
cesium equilibrium, over 40 percent of the daily cesium-137 intake
[p. 3]
appeared in the milk at the beginning of lactation, this proportion
decreasing to about 20 percent within a few months (Aarkrog,
1962).
2.7 Cesium, like potassium, tends to be found within cells, al-
though small extracellular concentrations are observed. Assays of
Japanese autopsy specimens (Yamagata, 1962) produced the
values in Table 1.
TABLE 1. CESIUM-137 CONCENTRATION IN TISSUES OF JAPANESE PEOPLE*
Tissues pCi of 1!7Cs pCi of "'Cs
per gm of tissue per gm of K
Muscle
Soft tissues . . .
Bone and marrow . . ,
Average all tissues ,
29 5
12.7
15.7
20.0
13.2
9.8
9.1
10.0
•From Yamagata, 1962.
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GUIDELINES AND EEPORTS 1329
2.8 Although the distribution of cesium is somewhat different
from that of potassium, over 55 percent of the cesium-137 burden
can be expected to be in the total muscle mass.
2.9 The retention of ingested cesium as a function of time is a
most important factor in any estimate of absorbed dose. Although
some data have suggested that there is little choice between an
exponential function and a power law function, retention studies
which have been extended over several hundred days favor a two-
component exponential function (Stewart et al., 1958; United Na-
tions Scientific Committee on the Effects of Atomic Radiation,
1964). The short lived component with a biological half life of the
order of one day contributes little to the total absorbed dose and
can be neglected.
2.10 Biological half life values for the long lived component
range from about 74 days (Liden, 1962) to 180 days (Stewart et
al., 1958) in adults, with lower values for children (United Nations
Scientific Committee on the Effects of Atomic Radiation, 1964).
The range of observed values appears to represent differences
among individuals rather than instrument or calibration errors.
Values obtained by whole body counting agree well with those ob-
tained by assays of excreta. A similar two-component exponential
retention function was found in the dog (Nold et al., 1962), with
biological half lives in a small series ranging from 18.8 to 40.9
days.
2.11 Data from adults are too meager as yet to permit a precise
determination of a most probable biological half life, and indeed
this value may be a function of the eating habits of a population.
Retention data in children are even more meager, and few children
have been studied for the lengths of time required to obtain good
values of biological half life. During the first decade after birth,
biological half lives for cesium-137 may be less than one-third of
the adult value.
[p. 4]
2.12 In the light of these uncertainties, a value of 100 days has
been taken as the biological half life of cesium-137 in normal adults
of the general population (United Nations Scientific Committee on
the Effects of Atomic Radiation, 1964). This value is almost cer-
tainly too large for children, perhaps by a factor of three to five.
The use of too large a value of the biological half life will lead to an
overestimate of the absorbed radiation dose.
2.13 Exposure to cesium-137 from weapons fallout is more apt
to be long-continued, at an approximately constant level, than is
exposure that might result from an industrial accident, which is
apt to be limited to a single, brief period.
-------
1330 LEGAL COMPILATION—RADIATION
2.14 To illustrate the build-up of a cesium body burden, let us
consider a steady-state situation in which there is a constant daily
intake of k nanocuries of cesium-137. If a biological half life of
100 days is assumed, the effective decay constant X = 0.693/100
= 6.93 X 10-3/day. At any time t days after the start of exposure,
the body burden B in nanocuries will be given by
E-l
£=A(i-e-A*)
= 144 &(1 ~ e-°-00693') E-2
There will be a maximum body burden at equilibrium of
BM = 144k E-3
but this value will be approached slowly. B will reach 90 percent
of its maximum value in about 330 days.
Dosimetry
2.15 In calculating the absorbed dose, it seems reasonable to as-
sume that the body burden is uniformly distributed throughout the
body. The variations in concentration between one tissue and
another are smaller than the uncertainties in the half-time of. re-
tention for a given individual. The tissue dose will come mainly
from the beta particles emitted by cesium-137 itself and from the
gamma rays emitted by its metastable daughter barium-137m
(ICRP, 1960). The range of most of the beta particles will ex-
tend well beyond cellular boundaries, so that extracellular tissues
will receive a radiation dose comparable to that delivered to the
interior of the cell.
[p. 5]
SECTION III
STRONTIUM-89 AND STRONTITJM-90
Metabolism
3.1 The behavior of strontium in mammals is inextricably linked
with that of other elements, especially calcium. It is also affected
by variations in nutrition, bone physiology, fetal development, and
lactation. It is not feasible in this report to attempt a rigorous
consideration of all such factors in estimating the hazard from
radiostrontium to man; instead, attention is given primarily to
-------
GUIDELINES AND REPORTS 1331
conditions that would result from short-term contamination, in
which case it is assumed that fresh cow's milk would be the prin-
cipal contributor to the body burden.
3.2 The metabolic properties described below are equally valid
for strontium-89 and strontium-90. In this discussion, radioactive
strontium is designated as Sr*.
3.3 After radiostrontium is ingested, part of it is absorbed from
the gastrointestinal tract into the blood stream and part is excreted
unabsorbed in the feces. That which is absorbed is (a) deposited
in the skeleton, (b) distributed in the soft tissues and circulating
fluids, or (c) removed from the body by urinary excretion and en-
dogenous fecal excretion (United Nations Scientific Committee on
the Effect of Atomic Radiation, 1962, 1964; Comar and Wasser-
man, 1964; Loutit, 1962; Caldecott and Snyder, 1960).
3.4 The pattern of skeletal distribution after short-term ex-
posure can be pictured as follows: Radiostrontium from the blood
rapidly enters the bone by ion exchange on the surfaces of bone
crystal and by incorporation into new bone which is being formed
in zones of growth and remodeling. This leads to focal areas of
highly localized radioactivity and diffuse areas of generally lower
concentration. In young, growing individuals and in cancellous
bone formation rates are relatively high, resulting in compar-
atively high local deposition and intensity of radioactivity.
3.5 The removal of radiostrontium from bone, once it has been
deposited, is relatively slow, depending mainly upon the extent of
bone resorption and mineral exchange.
3.6 The behavior of strontium in the body can be considered
either in terms of strontium itself or in terms of the relation be-
tween strontium and calcium (United Nations Scientific Com-
mittee on the Effects of Atomic Radiation, 1962; Comar and
Wasserman, 1964; Caldecott and Snyder, 1960; Wasserman, 1963).
Although the data on the retention of strontium in the body suffice
for estimating body burdens for short-term ingestion, analysis of
the strontium-calcium relationship facilitates estimating concen-
trations of radiostrontium in newly formed bone and in the entire
skeleton under conditions of protracted intake. The reasons for
this are (a) homeostatic control of calcium leads to a remarkable
constancy of calcium concentrations in most tissues and fluids;
(b) strontium metabolism is regulated more by calcium levels than
by normal amounts of stable strontium; and (c) strontium and
calcium movements are usually affected similarly by extraneous
factors. Extensive experimental evidence in man and animals
shows that the strontium-to-calcium ratio in tissues and secretions
[p. 6]
-------
1332 LEGAL COMPILATION—RADIATION
is directly related to the ratio that exists in the diet, within normal
dietary limits.
3.7 Organisms generally utilize and retain strontium less ef-
fectively than calcium; that is, they discriminate against stron-
tium in favor of calcium. The term "Strontium-Calcium Observed
Ratio" (OR) is used to denote the comparative strontium to cal-
cium ratios that exist at equilibrium in a given component of the
body and in its dietary precursor; for example,
_ Sr/Caofbone E-4
ORbone/diet = ~T ~
Sr/Ca of diet
3.8 The over-all discrimination, which is designated by the OR
value, is brought about by one or more physiological processes, of
which gastrointestinal absorption, renal excretion, placental trans-
fer, and mammary secretion are most important (Comar and
Wasserman, 1964).
3.9 The OR value is affected by age and dietary composition,
although the effects of the latter are small unless the diet is highly
exceptional. Under the usual dietary conditions the OR values
for older children and adults fall within a reasonably narrow
range, with few indications of variation by a factor as high as two
(United Nations Scientific Committee on the Effects of Atomic
Radiation, 1962; Comar and Wasserman, 1964).
3.10 In the movement of strontium and calcium between bone and
the exchangeable pools there is little or no discrimination between
the two elements. The terms ORb0ciy/d,<.t and ORj,0ne/diet are, there-
fore, used interchangeably. If the skeleton of an individual is
formed entirely from a diet of a given Sr*/Ca ratio, then all the
bone should have an essentially uniform concentration, equivalent
to (ORbone/d.et) X (Sr*/Ca of diet); an example of this would be
the case of a newborn child of a mother who had a constant dietary
Sr*/Ca during gestation.
3.11 Under conditions of short-term exposure to radiostrontium
or exposure to changing levels the situation is much more complex.
The highest concentrations are localized in "hotspots" which rep-
resent sites of active bone formation and are estimated to contain
about half of the deposited radiostrontium. The rest of the radio-
activity is diffusely distributed in bone at a considerably lower
concentration than in the "hotspots" (La Croix and Budy, 1962).
The theoretical maximum concentration is equal to the value of
(ORb«Wo,et) X (Sr*/Ca of diet). In actuality, it is expected that
the concentration in "hotspots" may be as low as half the theoret-
ical maximum because of the contribution of calcium from the
body stores.
-------
GUIDELINES AND REPORTS 1333
3.12 Also significantly influencing the deposition and retention
of radiostrontium is the rate of turnover of bone salts, or the rate
of replacement of existing mineral in the skeleton. Some con-
siderations suggest that the skeletal calcium of the newborn infant
turns over so rapidly that appreciable equilibration of skeletal
strontium to calcium ratio with the strontium to calcium ratio of
the circulating fluids probably occurs within a matter of weeks
(Comar et al., in preparation). This means that the strontium to
calcium ratio of the skeleton of the newborn infant will be gov-
[P. 7]
erned primarily by the strontium to calcium ratio of the diet dur-
ing the first few weeks, and perhaps months, after birth. In
infants and young children it has been estimated that about 50
percent of bone mineral is replaced annually, with an almost com-
plete replacement of skeletal mineral in the first two years of life
(Bryant and Loutit, 1964). In older individuals, a gradation of
replacement rates is thought to exist; for example, it is estimated
that the replacement rate in adult long bones might be about 1
percent per year as compared to about 10 percent in adult can-
cellous bones (Loutit, 1962). Those parts of bone with the highest
growth-rate are those in which are deposited the largest amounts
of the radiostrontium ingested over a short time period.
3.13 Typical data for estimation of body concentrations of ra-
diostrontium following short-term contamination of cow's milk are
summarized in Table 2. The values have been appropriately
rounded, since no single figure can be representative of an entire
population, and since the values are intended only for illustrative
comparisons and rough estimates.
3.14 The values for ORh0fiy/,i.et (column 1, Table 2) are as fol-
lows: for the fetus, a rounded value of 0.1 was used, although the
data in the literature would suggest values up to 0.13 (United
Nations Scientific Committee on the Effects of Atomic Radiation,
1962; Comar and Wasserman, 1964, Loutit, 1962); the OR value at
birth is close to 1 (Lough et al., 1963), decreasing to about 0.5 at 1
year of age and probably reaching the adult value of 0.25 sometime
shortly thereafter (United Nations Scientific Committee on the
Effects of Atomic Radiation, 1962; Loutit, 1962; Benison et al.,
1964); for pregnant and nursing women, the value accepted for
adults (0.25) was used.
3.15 The fraction of the calcium intake that might be derived
from fresh cow's milk was calculated from consideration of the
amount of calcium consumed in fresh milk (column 3, Table 2) in
relation to the total calcium intake (column 2, Table 2). The data
on column 2, Table 2, were derived from recommended dietary in-
-------
1334 LEGAL COMPILATION—RADIATION
takes (Food and Nutrition Board, 1958 and 1963) and in column
3, Table 2, from estimates of milk consumption in home and school
(Bureau of the Census and Division of Radiological Health, 1963).
The diet of babies less than 4 months of age will contain no fresh
cow's milk if they are breast-fed or receive formulas made with
processed milk; however, for purposes of comparison, an entry has
been made for such infants fed a diet based entirely on fresh cow's
milk.
3.16 The values in column 5, Table 2, which represent the max-
imum Sr*/Ca in new bone per unit of Sr*/Ca in cow's milk, were
calculated by multiplication of columns 1 and 4. The highest con-
centrations occur in the 4-6 month age group (except for the 0-4
month infant fed on fresh cow's milk) and are 2 to 5 times higher
than those calcuated for ages 6 months to about 20 years.
3.17 The daily retention of Sr* per unit of Sr*/gram of calcium
in fresh milk (column 6, Table 2) was calculated on the basis of a
gastrointestinal absorption of 30 percent (Lough et al., 1963; Gran
and Nicolaysen, 1964), neglecting endogenous losses, which are
small. These values do not apply to long-term ingestion, since
under chronic conditions the skeleton tends to approach a steady
[P. 8]
-------
GUIDELINES AND REPORTS
1335
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-------
1336 LEGAL COMPILATION—RADIATION
state with regard to Sr* entry and removal, and the excretion from
the body increases. From estimates of the total calcium of the
body (Mitchell et al., 1945), the daily retention of Sr* per unit of
Sr*/gram of calcium in fresh milk can be expressed in relation to
the amount of calcium in the body (column 8, Table 2). For ex-
ample, an adult man is estimated to consume daily 0.3 gm of cal-
cium from fresh cow's milk; if this milk contained 1 picocurie of
Sr*/gm Ca, it is assumed that he would consume 0.3 picocurie of
Sr* of which 30 percent, or 0.09 picocurie, would be retained. If
his body content of calcium were 1078 gm, then his daily retention
of Sr* per gram of calcium in his body would be about 0.00008
picocurie.
3.18 The rate of elimination of radioactive strontium from the
body, as influenced by age and other factors, is not well-known.
Studies in several species of laboratory animals have indicated that
the rate of excretion of strontium-85 varies markedly in relation to
age during the first few months after a single injection of the
isotope but later approximates the same power function in animals
of all ages (see Finkel, Bergstrand, and Graubard, 1960; Speck-
man and Norris, 1964; Decker et al., 1964). Limited human data
fitted with a power function and extrapolated to 40 years give a
long-term retention half life of 110 years, or 4.0 X 104 days (Cohn
et al., 1962), as compared with the half life of 1.3 X 104 days listed
by the ICRP (1960). The difference between the two half lives is
attributable in part to a relatively rapid rate of excretion during
the first several months, which can be described by three successive
exponential functions with half lives of 2.5, 13.7, and 843 days, re-
spectively (Cohn et al., 1962). Clearly, more data are needed over
longer intervals to enable confident prediction of the long-term
retention of radioactive strontium by human populations of var-
ious ages following short-term intake.
3.19 Although the initial concentrations of radiostrontium are
obviously highest in young infants fed fresh cow's milk, the turn-
over of the isotope and its removal from the body are also rela-
tively high in infancy. Because these opposing effects cannot yet
be balanced precisely, it is difficult to state unequivocally which age
group of the population may receive the largest cumulative radia-
tion dose from short-term ingestion of strontium-90. Strontium-
89, however, which has a physical half life of only 50.5 days, will
tend to be removed more slowly by excretion at all ages than by
radioactive decay, so that the cumulative radiation dose from this
isotope will depend primarily on its initial concentration in the
body.
-------
GUIDELINES AND EEPORTS 1337
Dosimetry
3.20 It is not yet possible to interpret the radioactive strontium
burden meaningfully in terms of the relevant resulting radiation
dose to the target tissue of interest, especially under conditions of
relatively short-term exposure to strontium-89 or strontium-90.
At any given time, the maximum local concentration of radioac-
tivity in the skeleton, and thus the maximum dose in "hotspots",
depends on the Sr*/Ca in new bone (column 5, Table 2). On the
other hand, the average concentration of radioactivity in the skel-
[p. 10]
eton, and thus the average dose to bone, is related to the ratio of
Sr* in the body to the total calcium in the body. Use can be made
of either of these values to estimate the corresponding doses in
rads (see Loevinger, 1956; Mays et al., 1959; ICRP, 1960; United
Nations Scientific Committee on the Effects of Atomic Radiation,
1964). The difference between the resulting two doses is large,
and which of the two, if either, is appropriate in estimating health
hazards is not clear. In general, however, values of the mean dose
to bone are used, although it is recognized that they would be
strictly appropriate only if the incidence of the effects in question
varied as a linear function of the dose to bone over a wide range
of doses. When the absorbed dose to the bone from these nuclides
is used in this report, it will refer to the mean dose in rads.
[p. 11]
SECTION IV
GENETIC EFFECTS
4.1 Appraisal of genetic injury is hampered by our inability to
measure the over-all damage resulting to the population from the
total effects of deleterious mutations. Nevertheless, it is accepted
that any increase in the mutation rate is undesirable, since muta-
tions are preponderantly harmful and are transmitted to succes-
sive generations. Furthermore, since any increase in the radiation
dose to germ cells is assumed to cause some increase in the muta-
tion rate, the National Academy of Sciences-National Research
Council Committee on Genetic Effects of Atomic Radiation rec-
ommended in 1956:
-------
1338 LEGAL COMPILATION—RADIATION
"That for the present it be accepted as a uniform national
standard that X-ray installations (medical and nonmedical),
power installations, disposal of radioactive wastes, experimen-
tal installations, testing of weapons, and all other humanly
controllable sources of radiations be so restricted that mem-
bers of our general population shall not receive from such
sources an average of more than 10 roentgens, in addition to
background, of ionizing radiation as a total accumulated dose
to the reproductive cells from conception to age 30.
That individual persons not receive more than a total ac-
cumulated dose to the reproductive cells of 50 roentgens up to
age 30 years (by which age, on the average, over half of their
children will have been born), and not more than 50 roentgens
additional up to age 40 (by which time about nine tenths of
their children will have been born)."
4.2 The 1956 report was written before it was demonstrated in
mice that, for those germ cell stages which, in man, are the ones
of primary concern, an exposure to low-dose-rate radiation is less
mutagenic than the same total dose given at a high dose rate. At
about the same time, the susceptibility of human chromosomes in
somatic cell cultures to breakage by radiation doses as low as 25 R
was reported. After weighing the various aspects of these and
other new developments, the Committee reiterated its position in
1960, reporting as follows:
"The Committee continues to recommend that for the gen-
eral population the average gonadal dose accumulated during
the first 30 years of life should not exceed 10 R of man-made
radiation, and should be kept as far below this as is prac-
ticable. This is in essential agreement with the most recent
suggestions of the International Commission on Radiological
Protection."
4.3 The Committee did not comment further at this time with
reference to the individual dose.
4.4 The last decade has been one of significant progress in ge-
netics and molecular biology. Many of the details by which the
DNA molecule replicates, mutates, carries information, and in-
fluences development are now known. The basic principles of pro-
tein synthesis under the control of DNA through the mediation of
RNA are beginning to be understood. The identification of DNA
with the gene has made possible a rational study of chemical muta-
[p. 12]
-------
GUIDELINES AND REPORTS 1339
tion, and a number of compounds known to affect DNA in one way
or another have been shown to alter the mutation rate. There has
also been considerable progress in understanding some of the
chemical steps in the induction of mutation by ultraviolet radia-
tion. The induction of mutation by ionizing radiation is less
understood at the chemical level, but the biological knowledge of
such mutation has been greatly increased. For example, the muta-
tion process has been found to be dependent on a great many var-
iables in a complex way. The stage of the cell in mitosis, the stage
in the life cycle, the amount of oxygen in the cell, and a number of
other factors have all been shown to be influential. There is also
strong evidence for cell selection that can diminish, or perhaps in
some circumstances increase, the impact of a mutation. When the
1956 report was written some of this was realized, but the problem
of estimating the damage from radiation seemed simpler in some
ways than it does now. In particular, at that time it was not
realized that the dose rate was of importance. The roles of this
and other factors, including complexities in the different muta-
tional responses of male and female germ cells, have now been re-
vealed through intensive studies in mice (Russell, 1963).
4.5 The science of human cytogenetics has been advanced con-
siderably since the 1956 report. It is now realized that several
types of human abnormality—severe syndromes with various
physical defects and mental retardation—are caused by chrom-
osomal aberrations. It is well established in experimental animals
that nondisjunction, chromosome loss, and translocation are in-
creased by radiation. Furthermore, it is now possible to study
chromosome breakage and rearrangement in humans in the same
manner as has been so productive of new information in plant
genetics. Recent reports emphasize that irradiation in vitro with
doses down to about 12 R causes about 1 percent of human somatic
cells to have chromosome abnormalities, and radiation workers re-
ceiving approximately 10 times the background dose have been
demonstrated to have a significant increase in abnormal chrom-
osomes in circulating white blood cells (Norman et al., 1964).
4.6 There have been almost no reports on the mutagenic effects
of radioactive strontium and radioactive cesium. Embryo mice
from fathers that had received intravenous injections of 0.7 micro-
curie of strontium-90 per gram of body weight have been reported
to have a higher frequency of cells with an abnormal number of
chromosomes than the controls (Henricson and Nilsson, 1964).
The authors stated that the results could be due to radiation-
induced aneuploidy in the germ cells, but suggested that another
type of damage not primarily connected with the chromosomes
-------
1340 LEGAL COMPILATION—RADIATION
may have been involved; namely, a radiation effect on the cell di-
vision mechanism that was transferred from spermatozoa to em-
bryos. The same large amounts of strontium-90 injected
intraperitoneally in mice have been reported to produce a signif-
icantly higher embryonic mortality in descendants than was found
in the controls or after injection of the same number of micro-
curies of cesium-137 (Liming et al., 1963a, 1963b). The effect was
interpreted by the authors as resulting from incorporation of
strontium-90 in the chromosomes. This interpretation raises the
question of whether radioactive stontium should be given special
consideration as a genetic factor. However, as the authors pointed
out, there are apparently some puzzling inconsistencies in the re-
[p. 13]
suits which cannot be resolved without further experiments.
Furthermore, even if the magnitude of the reported effect were
confirmed, it would still seem unlikely that it would prove to be the
limiting factor in setting up protective action guides for stron-
tium-90. In the first place, the doses to the mice were large (about
18 microcuries per mouse). Second, the length of time the stron-
tium stays in the germ cells, or even in their vicinity, is probably
only of the order of days, and most of it that is not deposited in
the bones is excreted.
4.7 A number of large-scale population studies on mammals
have been completed or are under way (see Roderick, 1964). In
general, doses delivered to mature germ cells at high dose rates
have been observed to cause detectable effects on viability, size,
and similar traits in the first generation progeny. Thus, large
doses given to rats have been shown to have a significant effect on
the maze-learning ability of their progeny (Newcombe and
McGregor, 1964). Also, a significant increase in skeletal abnor-
malities has been found in the offspring of irradiated mice (Ehling
and Randolph, 1962; Ehling, 1964). But experiments that have
utilized radiation to premeiotic germ cells have, in general, been
inconclusive, even when several generations have been examined.
The inconclusive nature of the experiments should not be regarded
as evidence against the existence of radiation-induced effects, but
rather as an indication of the difficulty of precise study of such
effects. Consistent with this thesis is the absence thus far of con-
clusive evidence of any substantial increase in overt genetic effects
in the offspring of the Japanese A-bomb survivors (United Nations
Scientific Committee on the Effects of Atomic Radiation, 1962).
4.8 Quantitative assessments of the genetic risk to human
beings from radiation exposure are difficult because of the fact
that almost all the information comes from experimental animals.
-------
GUIDELINES AND REPORTS 1341
The problems of differential cell sensitivity, dose-rate effects, inter-
cell selection, and the other complications all make it very difficult
to assess the full impact of radiation even on a mouse population.
In man the problem is compounded by the fact that the social im-
pact of mutation depends on a number of uniquely human factors.
The variety of effects that can occur as a result of mutation and
chromosomal anomaly, and the incidence of these, have been dis-
cussed repeatedly (National Academy of Sciences-National Re-
search Council, 1956, 1960; Medical Research Council, 1956, 1960;
United Nations Scientific Committee on the Effects of Atomic
Radiation, 1962; Federal Radiation Council, May, 1962).
4.9 In choosing the 10 R limit for population 30-year exposure,
the Genetics Committee thought, for a variety of reasons, that
doses below this level, although not desirable, would be acceptable
if there were compensating benefits. It was also thought that the
chance of genetic damage of such a nature as to affect the in-
dividual (by being expressed in his immediate family) would be
acceptably small if the individual dose were kept below 50 R. The
reasons for this conclusion still seem to be valid.
4.10 In reference to the dose of 25 rads of interest in this report,
it may be noted that this is below the level that the Genetics Com-
mittee set for an individual dose, and would presumably be re-
[p. 14]
ceived at dose rates lower than those which had to be considered
by that Committee. Furthermore, as long as the group exposed is
small, the average dose to the population will not be greatly
changed. Therefore, genetic considerations are not likely to be
limiting if the exposed group constitutes a small fraction of the
population.
[p. 15]
SECTION V
SOMATIC EFFECTS
Effects on Embryological Development
5.1 A single, brief exposure of the mammalian fetus to as little
as 10 or 20 R of X-rays has been noted to cause abnormalities of
brain development carrying over into adult life (Hicks and
D'Amato, 1963). Developmental skeletal abnormalities have been
-------
1342 LEGAL COMPILATION—RADIATION
increased in mice genetically disposed to show them following a
single, brief X-ray exposure at even the lowest dose level tested,
namely 25 R (Russell, 1957).
5.2 Protracted exposure of mice, on the other hand, to a con-
tinuous dose of 12 R a day throughout the first 15 days of preg-
nancy has been observed to produce no gross anatomical
abnormalities in the exposed offspring, although it shortened the
reproductive life of the exposed female young (Russell et al.,
1960). Exposure of pregnant rats to 1 R a day for 20 days has
been reported to cause detectable changes in the development of
behavior in the exposed offspring (Piontkovsky and Semagin,
1961; Piontkovsky, 1961); i.e., retarded development of condi-
tioned reflexes and poorly retained reflexes. The brains of the
affected offspring were said to be smaller than normal.
5.3 Effects of strontium-89 on development have been observed
in one study with mice (Finkel, 1947). The doses injected were
relatively high, 1 to 10 microcuries per gram weight in the preg-
nant animal. Strontium-89 was deposited in the bones of the off-
spring. The higher doses of strontium-89 resulted in stillbirth.
At lower doses of strontium-89, retarded growth, malformation of
the skeleton, anemia, and osteogenic sarcoma were noted.
5.4 Malformations have been increased in frequency in the hu-
man embryo and fetus by relatively large doses of radiation de-
livered at high dose rates. For example, an abnormally high
incidence of microcephaly with mental retardation has been noted
among Japanese children exposed in utero to the atomic bomb (see
Burrow et al., 1964). From the meager data available, however,
it is not possible to determine the relationship between the risk of
severity of such effects and the radiation dose.
5.5 On the basis of a small study, it has been suggested that
heterochromia of the iris may be related to prenatal diagnostic
X-ray exposure (Lejeune et al., 1960), but in a subsequent, much
larger study, the suggestion was not confirmed (Cheeseman et al.,
1963). At the present time it seems unlikely that there is a causal
association between prenatal X-ray exposure and heterochromia
iridia, although the possibility of a much lower order of associa-
tion than that originally reported cannot be unequivocally excluded.
Prenatal X-ray Exposure and Childhood Cancer
5.6 An association between prenatal X-ray exposure and the
incidence of cancer in childhood has been reported, which is im-
portant in the present context because of the relatively small dose
of radiation involved.
[P. 16]
-------
GUIDELINES AND REPORTS 1343
5.7 The original observation (Stewart et al., 1956; Stewart
et al., 1958) was that about twice as many mothers of children who
died of cancer reported diagnostic X-ray examination during the
relevant pregnancy as did mothers of normal children. The sig-
nificance of the finding was widely questioned because of the in-
vestigators' reliance on mothers' recall of X-ray exposures that
may have occurred up to 10 years before. However, a number of
subsequent studies, utilizing different methods, have confirmed the
observation, although at a somewhat lower level of association
than the original study (Ager et al., 1962; Ford et al., 1959; Kap-
lan, 1958; MacMahon, 1962; Polhemus and Koch, 1959). Some
regative studies have been reported (Court-Brown et al., 1960;
Kjeldsberg, 1957; Lewis, 1960; Murray et al., 1959; Wells and
Steer, 1961), but all are based on small numbers of cases and no
published study reports results significantly different (statistically
speaking) from the mean value quoted below.
5.8 No factor which might increase both X-ray exposure and
cancer rates and thus produce a spurious association has been def-
initely implicated, although most of the obvious possibilities have
been explored.
5.9 If the association is assumed to be one of cause and effect,
the maximum likelihood estimate of the cancer risk associated with
prenatal X-ray exposure can be calculated. Such an estimate,
based on pooled data from all published series (MacMahon and
Hutchison, 1964), calculated the cancer risk of the exposed to be
40 percent higher than that of non-exposed children, the 5 percent
confidence limits of this figure being 20 and 60 percent.
5.10 The X-ray dose involved in these exposures is not known
precisely. For comparable procedures in Great Britain in 1957-
58, the Adrian Committee reported a mean dose of 0.8 R to the
maternal gonad, but with a range among hospitals from 0.03 to
10 R. It is likely that mean doses in the earlier periods included
in the cancer studies were larger—perhaps between 2 and 5 R.
The fetal exposure is essentially to the whole body.
5.11 An assumption of linearity in the dose-response relation-
ship at a value of 2 leukemias per million exposed per year per rad,
commonly quoted for the relationship in adults, would under-
estimate the frequency of leukemias associated with fetal irradia-
tion by a factor of between 2 and 5. Associated with fetal
irradiation, there are, in addition, other types of cancer (tumors
of brain, kidney, and other sites) which have not so far been linked
to radiation exposure in adults. In all, between 4 and 10 times as
many cancer cases (leukemia and other cancers) are associated
with this type of antenatal exposure as would be postulated by as-
-------
1344 LEGAL COMPILATION—RADIATION
suming an incidence of 2 cases (leukemia only) per million per
year per estimated rad.
5.12 These data relate to what is essentially a single exposure—
the effect of fractionation is unknown. Also equivocal is the effect
of duration of gestation at exposure, the great majority of these
procedures being conducted in the last trimester of pregnancy.
One large study (Stewart et al., 1958) suggested higher risks for
children exposed early in pregnancy, but the finding has not yet
been confirmed by other work (MacMahon, 1962).
[p. 17]
Effects of Postnatal Exposure
Induction of Leukemia
5.13 An increased incidence of leukemia, a relatively rare dis-
ease in man, has been found in various population groups exposed
to external radiation in childhood or adult life, as well as in utero.
Data on animals given bone-seeking radionuclides indicate that
malignancies of hemopoietic tissues may result from internal, as
well as external, radiation exposure.
5.14 The incidence of leukemia in man has been observed to be
increased after a single dose of external radiation to the whole
body at a level of approximately 100 rads or more (Folley et al.,
1952; United Nations Scientific Committee on the Effects of
Atomic Radiation, 1964) and after irradiation of an appreciable
portion of the bone marrow with approximately 500 rads or more
(Court-Brown and Doll, 1959).
5.15 In the Hiroshima A-bomb survivors, the incidence of leu-
kemia increased progressively to a maximum between the 4th and
7th years after exposure and declined thereafter, but it was still
significantly above the control level in 1960. The incidence of leu-
kemia integrated over the first 15 years after irradiation increased
with dose at dose levels greater than approximately 100 rads. Al-
though the exact relationship between dose and incidence has not
been established, the increase above the natural incidence averaged
over the 15-year period can be calculated to be about 1 to 2
cases per million persons per rad for each year at risk after ex-
posure to 100-500 rads or more. It is not known how long the
annual incidence will continue to exceed normal.
5.16 The risk estimate given above cannot be applied to the pop-
ulation at large without reservation. The survivors in Japan were
heavily selected as a result of the early lethal effects of the ex-
posure; thus the irradiated survivors may not represent the entire
population with respect to susceptibility to leukemia induction. In
-------
GUIDELINES AND REPORTS 1345
addition, the increase in incidence more nearly approximated a
constant multiple of the natural age-dependent incidence than a
constant number of excess cases. Hence, the estimate is probably
too high in adolescent children and may be too low in adults; ad-
ditional data will be needed for accurate estimation in limited age
groups.
5.17 External radiation delivered at low dose rates to the entire
body or to a large segment of the bone marrow has also appeared
to be leukemogenic to human populations at high dose levels
(United Nations Scientific Committee on the Effects of Atomic
Radiation, 1964). Nevertheless, uncertainties about the influence
of dose rate, fractionation, and total dose under these conditions
make it impossible at present to estimate quantitatively the prob-
ability of leukemia under circumstances other than short-term ex-
posure to high doses. Long-term exposure is less leukemogenic
than short-term exposure for the same total dose if the dose-rate
dependency observed in animals (Mole, 1962; Upton, 1964) also
exists in man.
5.18 The types of leukemia showing a relationship to radiation
exposure are the acute forms and the chronic granulocytic form
(Moloney, 1959; United Nations Scientific Committee on the Ef-
[p. 18]
fects of Atomic Radiation, 1964). Related diseases also reported
to occur more often than normal in irradiated populations include
multiple myeloma (Lewis, 1964; Anderson and Ishida, 1964),
aplastic anemia (Lewis, 1964), myelofibrosis with myeloid meta-
plasia (Anderson et al., 1964), Hodgkin's disease (Anderson and
Ishida, 1964), and lymphosarcoma (Anderson and Ishida, 1964).
The commonest form of chronic leukemia in the United States and
the United Kingdom is the lymphocytic form, the incidence of
which has increased during recent years; however, no correlation
has been observed between previous radiation exposure and the
frequency of this disease.
5.19 The induction of leukemia and lymphomas in animals by
external radiation has been amply documented, but the dose-re-
sponse relation is not precisely known, and there is no conclusive
evidence that the frequency of these diseases is increased by less
than 50 rads (United Nations Scientific Committee on the Effects
of Atomic Radiation, 1962).
5.20 It is reasonably well established that iodine-131 admin-
istered in doses greater than 1 curie (e.g., for therapy of carci-
noma of the thyroid) may be leukemogenic to man (Moloney, 1959;
United Nations Scientific Committee on the Effects of Atomic Ra-
diation, 1964). Hemopoietic tissue receives a considerable radia-
-------
1346 LEGAL COMPILATION—RADIATION
tion dose in the course of such therapy; i.e., of the order of 1.0 rad
per millicurie (Sinclair, 1957; Hainan and Pochin, 1958).
5.21 It has not been established whether internal emitters se-
lectively deposited in bone (bone-seekers) are leukemogenic in
man. The apparent increase in leukemia among patients with
polycythemia vera (Osgood, 1964) treated with phosphorus-32 is
suggestive of this but not conclusive in the absence of an adequate
control population. Leukemia has been reported in dial painters
and other individuals who received radium internally some years
previously. Hasterlik et al. (1964) have reported two cases
(death certificates) of acute myelocytic leukemia in approximately
400 radium patients, one of which was confirmed by their study of
the original blood smear made shortly before the patient's death in
1931. An additional case of myelocytic leukemia has been reported
from a series of 150 radium patients studied in New Jersey; the
body burden of radium-226 was less than 0.0042 microcurie. No
leukemia has been found in a series of 237 individuals exposed to
radium studied by Evans and colleagues in Boston.
5.22 Although the human data in themselves are not sufficient to
establish that exposure to radium or other bone-seeking isotopes
will lead to an increased leukemia incidence in man, large amounts
of strontium-90 have been repoi'ted to cause leukemia in mice
(Watanabe, 1957; United Nations Scientific Committee on the Ef-
fects of Atomic Radiation, 1962) and other animals. Further-
more, the onset of leukemias and lymphomas in mice has been
found to be hastened with a dose of strontium-90 (8.9 microcuries
per kilogram) which did not detectably induce bone tumors or
shorten the life span (Finkel, 1959).
5.23 Preliminary results from experiments with dogs and swine
(Andersen and Goldman, 1962; McClellan and Bustad, 1964; An-
dersen and McKelvie, 1964; Biskis et al., 1964) suggest that stron-
tium-90 may induce leukemia and possibly other neoplasms of
[P. 19]
reticular tissues in these species also, but the data are too limited
as yet to disclose dose-effect relationships. The lowest average
dose at which such an effect has been observed thus far has been
estimated to be 900 rads, delivered throughout life to the skeleton
of a dog by strontium-90 administered daily in the diet. The an-
imal in question died at 192 days of age, after being fed since birth
a ration containing strontium-90 and after receiving strontium-90
in utero from its dam, which was fed the same ration (Andersen
and Goldman, 1962).
5.24 The development of leukemia in 6 chronically strontium-90
treated dogs having cumulative mean skeletal doses of 900-4000
-------
GUIDELINES AND REPORTS 1347
rads and in 3 chronically strontium-90 treated swine having cum--
ulative mean skeletal doses of 16,000-18,500 rads contrasts with
the absence thus far of bone tumors at these levels and the absence
of leukemias at higher dose levels, where instead bone tumors were
induced in high incidence (McClellan and Bustad, 1964; Andersen
and Goldman, 1962; Andersen and McKelvie, 1964; Biskis et al.,
1964). This dose and dose rate-dependent difference in the types
of neoplasms cannot be explained. It may, however, be related to
differences in (1) radiation dose rate, (2) radiation dose distribu-
tion, (3) age at exposure, (4) latent period of leukemias as op-
posed to bone tumors, or (5) other factors. Although the
apparent differences may not be real, they imply that animals ex-
posed chronically to strontium-90 from infancy may develop leu-
kemia at dose levels lower than those causing a comparable
increase in the incidence of bone neoplasms.
Induction of Bone Tumors
5.25 Therapeutic external irradiation has been followed in sev-
eral dozen human patients by development of osteogenic sarcoma,
the neoplasm in most cases arising at the site of a pre-existing
benign tumor or chronic inflammation (Bloch, 1962). The latent
period preceding the appearance of sarcomas has ranged from less
than 3 to over 30 years (Bloch, 1962). In some instances, gross
radiation damage to the bone was evident before the neoplasm ap-
peared, but in other instances this was not detected. The relation
between the incidence of sarcomas and the radiation dose cannot
be inferred from the information at hand, but 3000 rads is the low-
est dose thus far associated with the formation of such a tumor in
the absence of factors known to predispose to neoplasia (Jones,
1953).
5.26 Doses of external radiation down to 250 R have been re-
ported to induce osteogenic sarcomas in laboratory animals
(Koletsky and Gustafson, 1955; Binhammer et al., 1957; Cater
et'al., 1959; Finkel et al., 1964a, 1964b); however, the natural
frequency of such tumors is higher in these animals than in man,
suggesting that their susceptibility to radiation neoplasia may also
be higher. Precise information on dose-response relationships is
not available for any species.
5.27 An increase incidence of benign bone tumors (i.e., osteo-
chondromas) has been noted in children irradiated over the chest
with doses ranging from 60-600 R (Pifer et al., 1963). The few
tumors observed do not indicate the quantitative relationship be-
tween incidence and dose (Toyooka et al., 1963) but they suggest
-------
1348 LEGAL COMPILATION—RADIATION
that susceptibility to these effects may be higher in children than
in adults.
[p. 20]
5.28 The induction of bone tumors in man by internally de-
posited radionuclides is documented by an increase in the incidence
of osteosarcomas with increasing content of radium in the skeleton
(Marinelli, 1958; Hasterlik et al., 1964). The available data im-
ply that the tumor incidence more nearly approximates a sigmoid
than a linear function of the terminal radium burden (Marinelli,
1958), in keeping with comparable data from experimental mice
(Finkel, 1956), but the data are too scanty to define precisely the
dose-response relation. There is no evidence that the induction of
malignancy is associated with a terminal body burden of less than
0.4 microcurie of radium (United Nations Scientific Committee on
the Effects of Atomic Radiation, 1964). Analysis of the human
data is complicated by the fact that measurements of the terminal
body burden have been made decades after incorporation of vastly
larger amounts of radium and mesothorium into the skeleton, with
the result that estimation of the original body burden, and hence
of the total dose to the bone, involves assumptions about the frac-
tion excreted (Norris et al., 1955). Assessment of the relevant
tumorigenic dose is further complicated by large variations in the
macroscopic and microscopic distribution of radium within the
skeleton, the dose to different areas of bone varying by an order of
magnitude or more (Lamerton, 1960; Rowland, 1963).
5.29 Oncogenic effects of bone-seeking radionuclides other than
radium have been documented thus far only in laboratory animals,
and results of such studies are as yet fragmentary for species other
than the mouse (see Andersen and Goldman, 1962; Casarett et al.,
1962; Dougherty, 1962). In CFj mice, the oncogenic potency of
various radioelements, as compared with radium per microcurie in-
jected, has been tentatively estimated as follows: radium-226, 1.0;
strontium-90, 0.2; strontium-89, 0.1; calcium-45, 0.05; and pluto-
nium-239, 20 (Finkel, 1956). These comparative potency values
may not be valid at low levels of oncogenic effect, however, because
the dose-effect curves for the various nuclides are complex in shape
and not parallel. Furthermore, since the values were based on
comparison of the effects of the several nuclides in relation to the
respective amounts of radioactivity injected rather than in rela-
tion to the respective doses of radiation to bone, they may not be
applicable to animals that differ from mice in the geometry,
growth, and metabolism of their bones (Finkel, 1958). It has been
calculated for example, that the mouse skeleton absorbs only 32
percent of the available energy from strontium-90 plus yttrium-90
-------
GUIDELINES AND REPORTS 1349
contained therein, whereas the larger skeleton of the dog absorbs
79 percent and that of man 88 percent (Parmley et al., 1962). On
the basis of the mean dose to bone, plutonium-239 and radium-226
appear significantly more effective than strontium-90 in inducing
osteosarcomas in dogs (Dougherty, 1964), but the data are pre-
liminary and the basis for the differences remains to be deter-
mined; i.e., it is not clear to what extent the differences are
attributable to the higher effectiveness of the alpha particles from
plutonium-239 and radium-226, as compared with the beta par-
ticles from strontium-90 plus yttrium-90, or to what extent the
differences are attributable to other factors, such as distribution of
the radiation in bone.
5:30 The influence of time-intensity factors in the induction of
bone tumors is uncertain (Finkel et al., 1964b; Lamerton, 1960;
Lamerton, 1959). The relative tumorigenic effectiveness of mul-
tiple injections of a radionuclide, as compared with a single in-
jection of the same total dose, is difficult to evaluate because of
[p. 21]
differences in the distribution of the radioactivity within bone
under the different conditions of administration. There is ev-
idence, however, that irradiation at a low dose rate, through grad-
ual incorporation of strontium-90 into the skeleton from the diet
over a greatly protracted interval is substantially less oncogenic
than irradiation at higher rates (Finkel et al., 1960).
5.31 The effects of physiological variables on susceptibility to
induction of bone tumors are, likewise, poorly known. Strain and
species variations in susceptibility among rodents are marked and
unexplained (Lamerton, 1960; Law, 1960; Finkel et al., 1961).
Age variations, similarly, have been noted in the carcinogenic re-
sponse of animals to bone-seeking radionuclides, but it is not yet
possible in such instances to determine the extent to which the
observed variations may be ascribed to differences in uptake and
retention of the nuclide and to what extent they reflect differences
in radiosensitivity (Lamerton, 1960).
Tumors of the Thyroid
5.32 The relationship between irradiation and induction of thy-
roid tumors was evaluated in 1962 by a panel of the National Acad-
emy of Sciences-National Research Council (Federal Radiation
Council Report Pathological Effects of Thyroid Irradiation, 1962).
The conclusions reached at that time have been strengthened and
extended by findings in the interim (Saenger et al., 1963; Lindsay
and Chaikoff, 1964; Pifer and Hempelmann, 1964).
-------
1350 LEGAL COMPILATION—RADIATION
5.33 The situation at present may be summarized as follows:
external radiation delivered to the thyroid at dose levels above 100
rads has been correlated with the appearance of thyroid nodules in
human beings. In some studies, the incidence has appeared to be
proportional to dose within the range of approximately 100 to 300
rads, from which the risk over this dose range has been estimated
to be 1 per million person-years per rad during at least the first 16
years after exposure (United Nations Scientific Committee on the
Effects of Atomic Radiation, 1964). It has been suggested that
external radiation localized to the thyroid region alone (Pifer and
Hempelmann, 1964) and radiation from radioactive iodine
(Doniach, 1963) are less tumorigenic to the thyroid than is ex-
ternal radiation not so sharply localized. These studies imply that
exposure of tissues other than the thyroid contributes indirectly to
thyroid neoplasia or that the tumorigenic effect decreases with de-
creasing dose rate, or both; however, these questions remain open
at present. The bulk of the thyroid tumors associated to date with
radiation has occurred among people exposed to X-rays during
childhood.
Other Neoplasms
5.34 Tumors of epithelial and nbro-vascular tissue adjoining
cranial bone have been associated with irradiation from bone-seek-
ing radionuclides in laboratory animals and human beings (e.g.,
Casarett et al., 1962; Hasterlik et al., 1964). Such tumors include
squamous cell carcinomas of the paranasal sinuses, which are rare
in the general population. Although the increased frequency of
these neoplasms is attributable to radiation emanating from radio-
isotopes deposited in adjacent bone, quantitative dose-incidence
data for such growths are lacking.
[p. 22]
5.35 Tumors of tissues other than those mentioned in the fore-
going paragraphs have been induced by irradiation, but the rela-
tive increase in their incidence appears to have been small in man.
Therefore, although quantitative estimates are not possible, it is
unlikely that the over-all risk of malignancy from whole body ir-
radiation, as in the case of internally deposited cesium-137, will
exceed by any large factor the risk of leukemia, thyroid tumors,
and skeletal neoplasms (United Nations Scientific Committee on
the Effects of Atomic Radiation, 1964). By the same token, the
over-all risk of malignancy from exposure to internally deposited
radioactive strontium is unlikely to exceed greatly the risk of skel-
etal tumors, leukemia, and cancers of soft tissue adjoining cranial
bone.
-------
GUIDELINES AND REPORTS 1351
Other Somatic Effects in Children and Adults
5.36 Although a number of permanent effects other than malig-
nancy have been observed following postnatal exposure to radia-
tion, few are of concern at low dose levels. One of these is
nonspecific deterioration and life shortening from causes other
than neoplasia. Data on animals indicate a dose-dependent short-
ening of life-span. Data on human beings (Seltser and Sartwell,
1964) are, likewise, consistent with a life-shortening effect of ir-
radiation, but the relation to dose cannot be estimated from the
limited information available at this time. It is clear that the
effect is so small, however, as to be detectable only in sizable popu-
lations and at dose levels exceeding 100 rads.
5.37 Effects on the growth and development of bone and teeth
are well known (see Ellinger, 1957). Stunting effects are dose-
dependent and vary inversely in relation to age and maturity. Ef-
fects of this sort have been reported in Japanese surviving
exposure to A-bomb radiation in childhood (Greulich et al., 1953).
Such effects have not been documented, however, at dose levels
below 100 rads. Few data are available on their induction by ad-
ministration of radionuclides, although impaired growth and de-
formation of bone have been noted in dogs with burdens of 300
microcuries of strontium-89 at birth and in mice under similar
conditions (Finkel, 1947, and personal communication).
[p. 23]
SUMMARY AND CONCLUSIONS
The possible biological effects of irradiation from internally de-
posited strontium-89, strontium-90, and cesium-137 have been
reviewed. Particular consideration has been given to effects that
might result from uptake of any one of these isotopes by a small
fraction of the population over a short period of time under con-
ditions leading to a cumulative average absorbed dose of the order
of 25 rads or less to any tissue of the body within about one year
after contamination.
Because of differences in the behavior of radioactive strontium
and radioactive cesium in the body and differences in the radio-
active decay rate of their several isotopes, the implications of in-
ternally deposited radioactive strontium differ from those of
-------
1352 LEGAL COMPILATION—RADIATION
radioactive cesium. Cesium-137, a beta-emitter, is distributed rel-
atively uniformly throughout soft tissues and gives rise to a
gamma ray-emitting daughter element, resulting in irradiation of
essentially the whole body. Strontium-89 and strontium-90, on the
other hand, are localized chiefly in the skeleton and teeth and give
rise to energetic beta-rays, which are considered to affect mainly
the bone, bone marrow, and adjacent structures. Tissues remote
from bone, such as the gonads, receive comparatively little irradia-
tion from radioactive strontium, with the result that effects on
these tissues are regarded as non-limiting under the conditions of
interest in this report.
In the absence of direct observations of effects from internally
deposited radioactive cesium and strontium in human beings, the
evaluation has been based of necessity on extrapolation from the
effects of these radionuclides in experimental animals and the ef-
fects of irradiation from other sources in man. The observed
effects have resulted, however, from irradiation under conditions
that do not precisely duplicate those associated with deposition of
radioactive cesium and strontium in the human body under the
hypothetical conditions of interest. Hence, the conclusions de-
rived herein are considered tentative.
Risks of chief concern in the case of irradiation from internally
deposited cesium-137 under the conditions in question are con-
sidered to be the following:
1. Carcinogenic effects on the exposed embryo and fetus
An association between cancer incidence in childhood and ante-
natal diagnostic X-ray examination has been reported, which
implies that the frequency of cancer may be increased by a single
exposure of the fetus to high dose-rate whole body radiation at
dose levels of 5 rads or less (see paragraphs 5.6-5.12). If this
interpretation is verified, similar carcinogenic effects on the fetus
and embryo might result from 25 rads delivered over a period of
weeks by cesium-137, but the degree to which the incidence of any
such effect would be altered by the relatively low dose rates in
question cannot be determined from the data now available. The
reported association between prenatal exposure and cancer in-
volves a dose of radiation smaller than that associated with any
other comparable injury in man. It suggests that sensitivity to
radiation carcinogenesis may be several times higher before birth
than later in life. At present, therefore, the fetus is considered to
represent the critical segment of the population for a given dose
from cesium-137 under the conditions of interest in this report.
[p. 24]
-------
GUIDELINES AND REPORTS 1353
2. Effects on the development of the exposed embryo and fetus
Disturbances of growth have been noted in developing embryos
of experimental animals after a single X-ray dose as low as 10-20
rads. Effects on the development of the human embryo and fetus
might result, therefore, from comparable doses delivered by
cesium-137, although it cannot be predicted from the evidence at
hand what effects, if any, would occur at the low dose rates in ques-
tion, particularly since the total dose received at any given stage
in development would be small. The frequency and severity of any
such effects would be expected to depend on the age of the embryo
at the time of exposure.
3. Carcinogenic effects on the exposed child and adult
A dose-dependent increase in the incidence of leukemia, thyroid
tumors, and, to a lesser extent, other neoplasms has been observed
in man at dose levels of about 100 rads and more. The precise way
in which the incidence of these effects is related to the dose and
dose rate is not known, and it is not clear whether smaller amounts
of radiation can augment the risk of cancer. The excess incidence
of cancer demonstrably associated with high doses, however, is of
the order of one additional neoplasm per million person-years at
risk per rad, which can reasonably be assumed to represent an
upper limit of any effect that might occur at lower doses and dose
rates.
4. Genetic effects
It is assumed that any increase in radiation exposure to the germ
cells causes some increase in the mutation rate. Hence, heritable
effects may be expected to result from 25 rads under the conditions
in question. However, 25 rads is below the limit of 50 rads for an
individual recommended by the National Academy of Sciences-
National Research Council Committee on Genetic Effects of Atomic
Radiation in 1956. Furthermore, the radiation would presumably
be received at dose rates lower than those which had to be con-
sidered by that Committee and would therefore be less damaging.
Also, as long as the group exposed is small, the average dose to the
population will not be greatly changed. Therefore, genetic con-
siderations are not likely to be limiting if the exposed group con-
stitutes a small fraction of the population.
Risks of chief concern in the case of irradiation from strontium-
89 and strontium-90 under the conditions in question are con-
sidered to be the following:
-------
1354 LEGAL COMPILATION—RADIATION
1. Carcinogenic effects on the exposed embryo and fetus
The embryo does not take up radioactive strontium in its bone
until the second trimester, when its osseous tissues begin to min-
eralize, but thereafter it incorporates the element throughout its
skeleton. Indications that susceptibility to leukemogenesis by X-
rays may be 2-5 times higher during the fetal period than in later
life, and that fetal irradiation induces other neoplasms not known
to be associated with irradiation in the adult (see paragraphs 5.6-
5.12), imply that the probability of effects from a given concen-
tration of radioactive strontium in bone may be maximal during
prenatal development. On the other hand, retention of strontium
may be limited by metabolic factors to a greater degree during the
fetal period than later in life. Also irradiation from radiostron-
tium differs from X-irradiation in being concentrated in bone and
bone marrow and in being absorbed during an interval of months
[p. 25]
rather than seconds or minutes. The extent to which these differ-
ences may reduce the leukemogenic effectiveness of radioactive
strontium, as compared with that of X-rays, is not known. Thus,
whether exposure in utero to radiostrontium under the conditions
of interest would increase the incidence of leukemia and other can-
cers in the exposed child cannot be decided conclusively from ex-
isting data. The inference that the fetus is the most critical
member of the population must also be considered tentative.
2. Disturbances of skeletal groivth and development in the exposed
embryo and fetus
Since skeletal abnormalities have been noted in embryos of ge-
netically susceptible laboratory animals after a single X-ray dose
as low as 25 rads, it is conceivable that some human embryos might
be affected by 25 rads delivered over a period of months from
internally deposited strontium-89 or strontium-90. However,
mouse embryos given approximately 12 rads daily for 15 days by
continuous exposure to gamma rays showed no gross defects, pre-
sumably because the radiation was less effective at the lower dose
rate. Thus, it is highly questionable that such effects would occur
at a total dose of 25 rads under the low dose rates in question.
3. Carcinogenic effects on the exposed child and adult
Radioactive strontium has been observed to induce leukemia and
bone tumors in dogs and swine, but few such animals have been
studied to date, and the effects have not been demonstrated at
average dose levels below about 900 rads. It is not clear whether
-------
GUIDELINES AND REPORTS 1355
strontium-89 or strontium-90 under the conditions of interest (i.e.,
25 rads delivered over a period of months) would increase the
incidence of these forms of cancer in man. Any increment above
the natural incidence that might result under these circumstances
would, however, be small.
[P. 26]
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1360 LEGAL COMPILATION—RADIATION
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1362 LEGAL COMPILATION—RADIATION
4.2d AN ESTIMATE OF RADIATION DOSES RECEIVED
BY INDIVIDUALS LIVING IN THE VICINITY OF A
NUCLEAR FUEL REPROCESSING PLANT IN 1968,
DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE,
MAY 1970
FOREWORD
The recent growth in the utilization of nuclear reactors for elec-
trical generating plants has brought with it the need for nuclear
reprocessing plants that extract usable uranium and plutonium
from spent fuel elements. The Bureau of Radiological Health per-
forms a technical review and evaluation of the public health fac-
tors of all nuclear facilities and provides technical assistance to
State Health departments responsible for assessing population
exposure and radiation levels in the environment. The North-
eastern Radiological Health Laboratory, under the aegis of the
Division of Environmental Radiation, has undertaken an environ-
mental survey of the first commercial operating fuel reprocessing
plant in the United States.
The technical reports series of the Bureau's regional laborator-
ies and its Division of Environmental Radiation is used to publish
the results of research projects and technical evaluations of nu-
clear facilities. These reports are distributed to State and local
radiological health program personnel, Bureau technical staff,
Bureau advisory committee members, radiation safety officers,
libraries and information services, industry, the press, and other
interested individuals. These reports are also included in the
collection of the Library of Congress and the Clearinghouse for
Federal Scientific and Technical Information.
I encourage the readers of these reports to inform the Bureau of
any omissions or errors. Your additional comments or requests
for further information are also solicited.
JOHN C. VILLPORTH,
Director,
Bureau of Radiological Health.
[p. iii]
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GUIDELINES AND REPORTS 1363
PREFACE
The projected increase in the utilization of nuclear power for
electrical generating plants has resulted in both State and Federal
public health agencies placing increased program emphasis on the
surveillance of nuclear power plants. The Bureau of Radiological
Health provides recommended nuclear facility surveillance pro-
gram information for the guidance of health agencies. In order
to provide a better technical basis for environmental surveillance
recommendations, a series of field studies have been conducted at
operating nuclear facilities to obtain better data on radionuclides
in plant effluents and their subsequent distribution in the en-
vironment.
This field study around the Nation's first commercial nuclear
fuel reprocessing plant was for the purpose of identifying the
movement of critical radionuclides through the atmospheric and
aqueous environments in relationship to the fuel reprocessing
procedures. Technical data obtained from this study will be used
to: (1) develop minimum and optimum requirements for environ-
mental surveillance around nuclear fuel reprocessing plants, (2)
designate the radionuclides and environmental pathways of great-
est dosimetric significance, and (3) provide estimates and meas-
urements of the radiation dose to populations in the area of a
facility.
CHARLES L. WEAVER, Director,
Division of Environmental Radiation.
MORGAN S. SEAL, Director,
Northeastern Radiological Health Laboratory.
[p. iv]
CONTENTS
Page
Foreword iii
Preface v
Abstract ix
Introduction 1
Dose commitment factors 2
Estimates of dietary intake and exposure time period 4
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1364 LEGAL COMPILATION—RADIATION
Page
Treatment of data and limitations 6
Results and discussions 9
Summary 12
Recommendations 13
A. Population dose study 13
B. Continuous monitoring of the external environment around
NFS by means of field samplers 14
C. Radionuclide levels in wildlife 14
References 17
[p. vii]
TABLES
Page
1. Factors for calculating dose commitments 5
2. A summary of yearly dietary intakes and exposure times 6
3. Concentrations of radionuclides in environmental media collected
around NFS in 1968 (/iCi/liter or juCi/kg) 8
4. Dose commitment accrued in 1968 in the vicinity of Nuclear
Fuel Services 10
[p. viii]
ABSTRACT
The public health implications associated with a nuclear facility can be best
evaluated in terms of the radiation dose delivered to persons in the vicinity
of the facility. This report attempts, by use of the dose commitment concept
and surveillance data previously collected, to estimate radiation doses in 1968
to persons in the vicinity of a fuel reprocessing plant from ingestion and
inhalation.
The dose commitment accrued in 1968 to a hypothetical "typical individual"
is not thought to differ significantly from that for the average adult popula-
tion in the rest of New York State and is attributable essentially to fallout.
This commitment was 77 millirem from strontium 90 to the bone and 1.7
millirem whole body from cesium 137 delivered over a 50-year period.
For the hypothetical "maximum individual" the dose commitment to the
bone from strontium 90 is 532 millirem and the first-year dose following in-
gestion is 38 millirem. The whole-body dose from ingestion of cesium 137
and cesium 134 (mostly from deer meat) is 257 millirem. Preliminary data
-------
GUIDELINES AND REPORTS 1365
indicate that the external gamma dose above natural background is approxi-
mately 1.2 millirem per year to the "maximum individual." Estimated doses
from tritium and krypton 85 were negligible (~-2 millirem/year).
[p. ix]
ACKNOWLEDGEMENT
Grateful appreciation is expressed by the Environmental Radiation Activi-
ties Staff, Northeastern Radiological Health Laboratory, to the New York
State Health Department and the Atomic Energy Commission who provided
the radioactivity data for this report. In addition, the encouragement of
Mr. Charles L. Weaver and the cooperation of the Division of Environmental
Radiation, Bureau of Radiological Health, insured the successful completion
of this study.
[p. x]
AN ESTIMATE OF RADIATION DOSES RECEIVED BY INDIVIDUALS
LIVING IN THE VICINITY OF A NUCLEAR FUEL REPROCESSING PLANT
IN 1968
INTRODUCTION
The public health implications associated with a nuclear facility
can best be evaluated in terms of the radiation dose delivered to
persons in the vicinity of the facility. The Bureau of Radiological
Health, Environmental Health Service, is at present investigating
radiation levels around nuclear reactors and around a nuclear fuel
reprocessing plant. Nuclear Fuel Services, Inc., processes spent
fuel from nuclear reactors on a 3,300 acre site 30 miles southeast
of Buffalo, in the town of Ashford, Cattaraugus County, N.Y.
The company began to dissolve fuel in April 1966, and, beginning
in September 1966, began discharging waste materials. Environ-
mental surveillance around NFS has been performed since 1965
by the New York State Health Department (1). The AEG carries
out an independent surveillance program (2). By 1968, meth-
-------
1366 LEGAL COMPILATION—RADIATION
odology and reporting were routine (3), and dosimetric calcula-
tions were made with data from this year. In addition to routine
sampling, special studies on tritium (3H) and krypton (85Kr) in
air were performed in 1967 (4, 5) and 1969 (6), and also provide
basic information for this paper.
The purpose of the project around Nuclear Fuel Services (NFS)
is to characterize completely the atmospheric and aqueous environ-
ments in relationship to the fuel reprocessing procedure in order
to designate which radionuclides are of greatest dosimetric sig-
nificance. This is being done through a series of field trips to
make specific radiological measurements and through a review of
previous surveillance data in an effort to extract dosimetric in-
formation. This paper describes the assumptions and procedures
for determining radiation doses to persons in the vicinity of Nu-
clear Fuel Services during 1968 and presents and discusses these
doses. Further, it relates the concentration of radionuclides in
milk, drinking water, deer meat, fish, and air around NFS and
their intake by humans.
[P. i]
External radiation measurements are also discussed. Doses are
calculated in terms of "dose commitments"; i.e., the dose delivered
(in millirem) to a critical organ during a 50-year period (or dur-
ing life) from a particular intake. Use of the dose commitment
concept provides a means of determining the relative significance
of doses due to human intake.
The internal radiation dose commitment for an individual in a
population group, due to a specific radionuclide, is the product of
(1) the factor for converting activity intake to dose, (2) the
weight or volume intake of the media per individual per unit time,
and (3) the concentration of the radionuclide per unit weight or
volume of media. The dose commitment concept applied to the
population of the northeastern United States for the years 1961-
1968 has been described in detail elsewhere (7). Other investi-
gators have employed a similar method in the estimation of
population doses in the environs of a nuclear facility (8).
DOSE COMMITMENT FACTORS
Selection of factors for converting activity intake to dose has
been previously described in detail and is beyond the scope of this
presentation (7). However, it is pertinent to briefly discuss dose
variables which influence the selection of dose commitment factors.
Dose commitment factors for airborne tritium and krypton 85,
which were not included in the earlier work, are presented in more
detail.
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GUIDELINES AND REPORTS 1367
Selection of factors for converting activity intake to dose re-
quires consideration of a variety of age dependent variables such
as: effective energy and half-time of the radionuclide in the organ
of reference, fraction of intake reaching the organ of reference,
and organ mass. Furthermore, factors employed in the calcula-
tion of radiation dose also vary depending on the mode of intake
and the solubility of the radionuclide.
Selection of radionuclide and population groups for which dose
commitments are calculated is constrained due to limitations in the
data available from environmental networks. For complete ra-
diological evaluation one should be concerned with all population
groups, since that group subject to the greatest radiation expo-
sure is not always immediately discernible. However, due to
limitations in the availability of data, doses have been calculated
for only two population groups. The first designated as a "typical
individual," is a hypothetical adult individual ingesting "average"
concentration of specific radionuclides based on local environ-
mental surveys. The second group, represented by a hypothetical
[P. 2]
"maximum individual" is assumed to ingest half the dietary intake
qualities that the "typical individual" ingests. This intake is
supplemented by deer meat from animals caught onsite or near
NFS and personally caught fresh fish from the mouth of Catta-
raugus Creek. This assumption was made because it is unlikely
that the "maximum individual" would ingest the same quantities
of food as a "typical individual," and in addition, deer and fish. A
more likely case would be that half his diet would be from hunting
and fishing. The radionuclide content of the diet, deer, and fish,
the "maximum individual" ingests is assumed to contain the "max-
imum" concentration of specific radionuclides. Doses from tritium
and krypton for the "typical individual" are based on exposure to
average air concentrations of 3H and sr>Kr over a 168-hour week.
For the "maximum individual" these doses are based on exposure
to the estimated maximum annual air concentrations of 3H and
85Kr which are assumed to be present 1.5 km from the plant at the
property line. This point being the closest that there might be an
inhabited dwelling. A 168-hour per week exposure is assumed.
Although all fission products and transuranic elements may be
potential human hazards under specific environmental conditions,
the radionuclides !M)Sr, 137Cs, 134Cs, b"Co, in6Ru-Rh, 3H, and 85Kr are
those for which data on concentrations in milk, food, and air
around NFS are available. Dosimetric evaluations in this paper
will be limited to these radionuclides alone.
Since radionuclides incorporated into the food chain are likely to
-------
1368 LEGAL COMPILATION—RADIATION
be soluble, this physical state was assumed for all radionuclides
present in milk, food, and drinking water.
For radionuclides having short effective half-times in the organs
of interest, the majority of the total dose commitment is delivered
during the first year after intake. Radionuclides with effective
half-times in an organ of 100 days or less (i.e., 137Cs, 134Cs, 60Co,
108Ru-Rh, 3H, and S5Kr) deliver 90 percent of their total deliverable
dose during the first year. Therefore, for the above radionuclides,
the dose delivered in the first year after intake and the dose com-
mitment (i.e., 50 years of lifetime dose) are equivalent. For 90Sr
approximately 7 percent of the dose commitment is delivered in
the first year after intake (11).
Doge factors used in this paper have all previously appeared in
the published literature. The dosimetric models for °°Sr, 137Cs,
and 3H (ingestion) and the modifications necessary for application
of the models to environmental radioactivity have been previously
discussed in great detail (7). Dose commitment factors for 134Cs,
60Co, and 10"Ru-Rh also appear in the literature (12). The values
used in a model for organ mass, effective energy and half-life and
radionuclide transfer from diet to the organ of interest are those
recommended by the ICRP (13).
[p. 3]
Some further explanation is required concerning the dose com-
mitment factors for 3H and 8sKr in air. The major route of expo-
sure of these radionuclides by humans is by inhalation and skin
absorption for 3H and by submersion in air for 85Kr. The dose
commitment factors used, as stated in the reference (14), are:
3.6 • 104X for 3H and 4.0 • 104X for S5Kr for a 168-hour week,
where X is the radionuclide concentration in /tCi/cm3. The con-
centration in the reference is stated in terms of /iCi/cm3 of air and
the estimated dose is calculated in rem per week. These equations
are then converted to dose per year instead of dose per week (• 52);
millirem instead of rem (-103); and /xCi/liter instead of /iCi/cm3.
When the radionuclide concentration is in terms of /xCi/liter, the
term Xa is used in the equation. The above conversions yield dose
commitment factors for 3H and S5Kr of 1.87 • 10°Xa and 2.08 •
10GXa respectively. The short biological half-times of 3H and 85Kr
in the body make the dose delivered in the first year after exposure
comprise the entire dose commitment from these radionuclides.
Of course, continuous plant operation would lead to continuous
exposure to these radionuclides.
Factors for relating activity intake to dose commitment, in
terms of millirem dose per 50 year (or life) are presented in table
1. These factors relate activity intake to dose for a single intake
-------
GUIDELINES AND REPORTS
1369
situation. A continuous intake situation can, however, be viewed
as a series of discrete intakes. This is valid if variation in activity
intake during the period of intake is minimal, if metabolic and
ingestion factors during the period of intake and dose commitment
remain constant, and if the intake period is short relative to the
period for which the dose commitment is being calculated.
ESTIMATES OF DIETARY INTAKE AND EXPOSURE TIME PERIOD
Direct measurement of dietary intake is not available for pop-
ulations in the vicinity of Nuclear Fuel Services. Measurement of
radionuclide milk concentrations, however, provides an indirect
measure of total radionuclide intake. Extensive studies in New
York City indicate that in 1968 the contribution of 90Sr intake from
milk was 37 percent of the total 9"Sr intake (15). This relation-
ship can then be used to estimate total ""Sr intake from milk data
alone. Similarly, the intake of 13TCs from milk in late 1967 (Chi-
cago) was 30 percent of the total 137Cs intake in the whole diet
(16). The intake of 3H from milk to the total diet is assumed to
have the same ratio as the liquid intake from milk to the total
liquid intake (9) (i.e., 40 percent). These data are used to esti-
mate the total dietary intake of the above radionuclides from their
reported levels in milk.
[P. 4]
TABLE 1. FACTORS FOR CALCULATING DOSE COMMITMENTS
Radionuclide1
Critical
organ
Mode
Dose commitment factor2
(millirem per 50 year
per /iCi intake)
"Sr (7)
"'Cs (7)
"
-------
1370 LEGAL COMPILATION—KADIATION
These figures are in agreement with the dietary intake studies
conducted by the USDA of the fish and fish products intake of
commercial fishermen (17).
As previously stated, the "typical individual" and the "maximum
individual" are presumed to be exposed to 3H and 83Kr concentra-
tions for the same period of time (168 hours per week) albeit at
different concentration levels.
A summary of dietary intakes and exposure periods appear in
table 2.
[P. 5]
TABLE 2. A SUMMARY OF YEARLY DIETARY INTAKES AND EXPOSURE TIMES
Media
Milk
Peer
Fish
Drinking water .
Air
River bank
Typical
310 liter
2 ke
5 5 kg
440 liter
0 hours
Maximum
380 liter
50 kg
40 kg
730 liter
8 736 hours
200 hours
TREATMENT OF DATA AND LIMITATIONS
Samples for analysis of 90Sr, 13?Cs, and 3H in milk were obtained
from ten farms in Cattaraugus County, N.Y. For 1968, a total of
180 samples were analyzed by the State of New York Department
of Health by radiochemical and/or gamma spectrometric analysis
(J). About one-quarter that number of public drinking water
samples were analyzed in the same year by the AEC (2).
Analytical errors in radiochemical analysis are usually between
5 and 10 percent. Sampling errors are difficult to evaluate. How-
ever, variations in results for 90Sr and 13rCs in milk, averaged over
the northeastern United States, yield standard deviations which
are, in most cases, less than 25 percent of the mean value; although
in several instances standard deviations as high as 50 percent of
the reported means have been encountered (7). Variations in
data around NFS, representing a much smaller sample size, can
be expected to reflect ranges in results at least as great.
Radionuclide levels in deer samples, 14 in number during 1968,
represent concentrations in the meat only. Unfortunately, due to
sample preparation techniques, this is not the case for fish samples
(9 during 1968), and the level represents radionuclide concentra-
tions in whole fish. The deer meat samples were obtained from
animals throughout Ashford Township; the maximum value was,
however, from an animal killed onsite. All fish samples were
[p. 6]
-------
GUIDELINES AND REPORTS 1371
caught at the mouth of the Cattaraugus Creek. In addition to 90Sr
and 137Cs, these samples were analyzed for 134Cs, 60Co, and 106Ru-
Rh. Because °°Sr tends to concentrate in bone, the whole fish
sample when used to estimate dose would tend to overestimate the
dose from 90Sr. Tritium was not analyzed in fish flesh, and it is
assumed that a reasonable estimate of its concentration in fish is
the same as its concentration in surrounding water (i.e., 3H in the
environment and fish assumed to be in equilibrium). Doses are
calculated from the average and maximum concentrations of spe-
cific radionuclides in a media over a 1-year (1968) period of time.
Airborne levels of 3H in the environs of NFS were not available
for 1968 and were indirectly obtained from 1967 surveys. A study
during that year determined the tritiated moisture content in 700
air samples around NFS (4). To convert these values to 3H in
air, calculations were made for the weight of water in air (based
on 25° C and 50 percent relative humidity) and the density of air;
so that the concentrations of 3H per liter of air is 1.18 • 10~5 times
the concentration of 3H per liter of moisture. The large quantity
of data from this survey was further analyzed and weighted for
variations in the yearly wind rose pattern yielding an estimate of
average 3H concentrations over a 1-year period. An estimation of
the maximum annual 3H air levels present near a point 1.5 km
from the plant at the property line was obtained from the above
study. This is the closest habitable dwellings might be established
without land sale by the plant.
Similar treatment was accorded 85Kr. Average 83Kr levels had
been directly determined in 1968 (5 measurements) (5). The
recent evaluations performed by the Northeastern Radiological
Health Laboratory provide estimates of the maximum annual con-
centration to which the "maximum individual" might be exposed.
This measurement was obtained for a 3-hour period during reactor
fuel dissolution. Based on wind rose data, 85Kr concentrations
could not be constant in any single direction (octant) for more
than 20 percent of the time; and this factor is also considered in
estimating the maximum concentrations over a year's period of
time. A yearly stability profile assumed 33 percent of the time in
each of the three following stability conditions: Moderately to
Extremely Stable, Slightly Stable, and Slightly Unstable. The
maximum annual S5Kr concentration has been estimated for a
point 1.5 km from the plant at the property line.
Results of environment sampling used to calculate dose com-
mitments appear in table 3.
[p. 71
-------
1372
LEGAL COMPILATION—RADIATION
TABLE 3. CONCENTRATIONS OF RADIONUCLIDES IN ENVIRONMENTAL MEDIA COLLECTED AROUND NFS IN
1968 (jiCi/UTER OR jiCi/kg)
Radionuclide
"Sr
"'Cs
1"CS
"Co
'WRu-Rh
3H
«Kr
Media
Milk
Deer1
Fish*
Milk
Deer
Fish
Deer
Deer
Fish
Fish
Milk
Deer
Fish
Drinking water
AirJ
Air
Average
11-10-'
11 -10-5
34-10~s
27 • 10-'
13 -10~'
63 -10-5
26 • 10-'
. —
21 • 10 -'
85 • 10-s
<12 • 10-'
30-10-'
12 • 10-'
< 3- 10-'
3-10-'
23-10-'
Maximum
21-10-'
54 -10-5
64 -10-5
12 • 10~s
67-10-'
36-10-'
12-10-'
90-10*
30-10-'
21 • 10-'
23-10-'
46 • 10-'
50-10-'
10 • 10-'
8-10-'
<13-10-«
1 Deer—meat only.
* Fish—whole fish.
' Survey carried out in 1967.
' Survey carried out in 1969.
Studies by the AEC (2) show the mean results of TLD monitor-
ing at five locations around NFS to be less than 4 millirem 1 (at
the 99-percent confidence level) above background for two monthly
periods during 1968 (October 6th through November 15th, and
November 15th through December 15th). One location may have
been as high as 5 millirem above background - for an approximate
1-month period. Data supplied by New York State reported an
[p. 8]
average reading of 4.8 milliroentgens per month above background
as measured with a pressurized ion chamber along the Cattaraugus
Creek on three occasions in 1969.3
RESULTS AND DISCUSSIONS
The dose commitments accrued in 1968 to a "typical" and
"maximum individual" around Nuclear Fuel Services are pre-
sented in table 4. The major dosimetric intake for a "typical
individual" was due to 90Sr and 13TCs ingestion in the diet. A dose
commitment from dietary "°Sr of 77 millirem and from dietary
1 Dose measured in millirads, converted to millirem by use of an RBE of one. Dose measured
with shielded dosimeters and thus represent gamma dose component only.
- Measured with open window dosimeter, and therefore represents beta and gamma components.
3 6.7 microroentgens/hour X 24 hour/day X 30 days/month equal 4.8 milliroentgens/month.
This is in terms of exposure dose rather than absorbed dose since the tissue equivalency of the
ion chamber is not known. The AEC data are in terms of absorbed dose (39).
-------
GUIDELINES AND EEPORTS 1373
137Cs of 1.7 millirem can be compared to dose commitments of 72
millirem and 1.3 millirem, respectively from the intake of these
radionuclides during 1968 based on milk samples collected in other
parts of New York State (362 samples). Considering analytical
and statistical variations in the data, the dose commitment from
diet to the "typical individual" around NFS does not differ sig-
nificantly from that of the average adult population of the rest of
New York State and can be attributed largely to fallout. The dose
commitment from other radionuclides to a "typical individual,"
including 3H and 85Kr in air, was less than 2 millirem. When one
considers the addition of local fish and deer meat to the diet, it is
observed (from table 4) that the °°Sr dose commitment to the
"typical individual" is increased by 20 percent and the 137Cs dose
commitment doubled.
As previously noted, except for the dose commitment from n°Sr,
all of the dose commitments from other radionuclides are essen-
tially delivered in the first year after intake. The total dose de-
livered in the first year after intake to a "typical individual" is
low compared to the Federal Radiation Council recommendation
for a suitable sample of the population (500 millirem per year to
bone and 170 millirem per year to the whole body) (19). The
total dose for a "typical individual" is approximately 1 percent of
the FRC's Radiation Protection Guide for bone and less than 3
percent of the Guide for the whole body.
The dose commitments in 1968 were in the same dosimetric
range as doses from natural radioactivity (80 to 200 millirem per
year), or approximately 2 percent of the dose commitment from
natural radioactivity (5,000 millirem in 50 years) (20). This is
consistent with data on studies of population in the northeastern
United States which found the n°Sr bone dose commitment from
fallout over a 7-year period to be 10 percent of the 50-year natural
radiation dose (7).
[p. 9]
-------
1374 LEGAL COMPILATION—RADIATION
TABLE 4. DOSE COMMITMENT ACCRUED IN 1S68 IN THE VICINITY OF NUCLEAR
FUEL SERVICES
Dose commitment'
(millirem)
Critical
Radionuclide organ
"Sr2 Bone
1J7Cs Whole body
'MCs Whole body . . .
»Co G.I. tract
'«Ru-Rh G.I. tract
'H Whole body
"Kr Whole body
Media
Diet1 . .
Deer ...
Fish
Diet
Deer
Fish
Deer . .
Deer
Fish
Fish
Diet
Deer
Fish
Drinking water
Air (inhalation
and skin
Submersion in air
Typical
individual
77
J.9
16
1.7
1.6
0.2
0.4
<0.01
0.05
0.9
<0.1
0.1
<0.01
<0.17
<0.05
0.05
Maximum
individual
90
227
<215
4.5
'200
8.6
48
0.2
0.5
16.4
0.3
0.3
0.3
1.0
0.1
0.3
i Dose per 50 years or per lifetime.
2 For »Sr co 7 percent of the dose commitment to bone delivered is delivered during the firs! year
after intake:
Diet: 5.4 millirem (typical) and 6.3 millirem (maximum).
Deer: 0.1 millirem (typical) and 16 millirem (maximum).
Fish: 1.1 millirem (typical) and 15 millirem (maximum).
For other radionuclides >90 percent of the dose delivered in the first year after intake.
3 Diet intake indirectly determined through use of radionuclide value reported in milk.
" Represents whole fish. The majority of *>Sr concentrates in bone which is usually considered inedible.
Therefore the dose commitment may represent a high estimate.
5 From sample caught onsite.
[p. 10]
From table 4 it can be seen that for the "maximum individual"
the dietary 90Sr and 137Cs dose commitments in 1968 are higher
than for the "typical individual," even though he was assumed to
have half the dietary intake (in terms of quantity). This is due
to an increase in the maximum concentrations of °°Sr and 137Cs in
milk when compared to the average concentrations. More sig-
nificantly, the ingestion of deer meat and fish increased the dose
commitments to the "maximum individual" from °°Sr and 137Cs,
and also from 134Cs and 10GRu-Rh.
The additional dose from e°Co is minor. In the case of the
"maximum individual" his total dose commitment accrued in 1968
to bone from 90Sr is 532 millirem. However, this includes analysis
of whole fish which would tend to overestimate 90Sr intake. To the
-------
GUIDELINES AND REPORTS 1375
whole body from 13TCs and 134Cs it is 257 millirem based on meat
from a deer trapped onsite. In the first year following intake,
the °°Sr dose would be 38 millirem or less than 3 percent of the
dose recommendations as they apply to the maximum exposed
individual.4 The whole-body dose from ingestion to the "maximum
individual" is estimated to be 50 percent of the dose recommenda-
tions for the maximum exposed individual. In addition to the
above doses the "maximum individual" might receive a 17 millirem
dose to the gastrointestinal tract, the majority of it due to inges-
tion of 10GRu-Rh in fish. Assuming the "maximum individual"
ingested 50 kg of deer meat and 40 kg of fish per year, the data
suggest that the maximum intake of deer meat be limited to about
100 kg of deer meat and 300 kg of fish per year. The suggested
allowable consumption agrees with recommendation made by
others for deer meat (21). It is highly unlikely, based on diet
studies, that the allowable intake of fish would ever be consumed.
The contribution of 3H to the whole-body dose commitment of a
"maximum individual," both from ingestion and air exposure is
minor compared to the above doses. It amounts to 2 millirem, the
majority of which is accrued via drinking water. The sr>Kr dose
due to air submersion is 0.3 millirem. This dose must be con-
sidered in light of the assumptions for wind direction, point of
exposure, and period of exposure made above.
Data on external radiation exposure indicate a mean gamma
dose around NFS of 4 millirem per month above background.
This would amount to an additional whole-body exposure of ap-
proximately 1.2 millirem for the "maximum individual" who
might spend 200 hours per year fishing. This dose is, because of
its mode of measurement, mostly gamma and probably results from
stream and silt contamination by gamma emitting radionuclides.
[p. li]
The above discussion is limited to estimates of dose commitments
accrued and avoids delineation of the size of the population at
risk. Some preliminary data are available which provide a general
idea of the size of the populations involved. Census data (1960)
indicate populations of approximately 6,000, 16,000, and 170,000
persons living within a 5-mile, a 10-mile, and a 25-mile radius of
the plant respectively (24). Perhaps more significant are data
available on the number of hunters and fishermen in the area. It
The FRC recommendation for individuals is interpreted to apply to the maximum ex-posed in-
dividual. For bone this is 500 millirem/year versus 1,500 millirem/year (19). The AEC regula-
tion limit of 500 millirem/year whole body to any individual is interpreted to apply to the
vn.fty.imiivn. frnnaerl ividiitirliiftl t ?? 93^
maximum exposed individual (22,23).
-------
1376 LEGAL COMPILATION—RADIATION
is estimated by the New York State Health Department that three
to four dozen hunters are present near the site during hunting
season and less than one dozen at other times (25). A survey
performed by the Conservation Officers of Regions I and II, New
York State Conservation Department (25) during three week days
and three Saturdays and Sundays in July-August 1969 indicated
heavy fishing pressure in the Springville area (approximately 6
miles from the site) and near the inlet to Lake Erie (approx-
imately 25 miles from the site) when compared to other sites fed
by the Cattaraugus Creek. Most fish caught were for personal
consumption. At the first site noted above 44 persons were fishing
during the survey period, averaging 4 to 10 fishing trips per year.
This survey indicated one individual fishes 180 days per year and
that maximum consumption might be as high as 160 kg per year.
At the second site mentioned 62 persons were fishing during the
survey period, averaging 10 trips per year although many in-
dividuals averaged 30 to 40 trips per year. It may be expected
that more intense fishing pressures occur during the April and
May trout fishing season. Furthermore, since the survey covered
a short period of time, yearly figures might differ. In any case,
the above data, while valuable does not definitively evaluate the
size of the populations described in this report.
SUMMARY
The dose commitment concept when applied to a "typical in-
dividual" and "maximum individual" in the vicinity of Nuclear
Fuel Services provides a simple means of determining significant
environmental surveillance data. Based on surveys carried out by
the New York State Department of Health, the Bureau of Ra-
diological Health, U.S. Public Health Service, and the Atomic En-
ergy Commission, the dietary dose to the "typical individual"
around NFS in 1968 is not thought to differ significantly from that
for the average adult population of the rest of New York State
and was attributable essentially to fallout. This dose commitment
(77 millirem) was approximately 2 percent (in one year) of the
dose commitment from natural radioactivity over a 50-year period.
When ingestion of typical amounts of deer and fish were added to
the diet, the dose delivered in the first year after intake was ap-
proximately 1 percent of the FRC recommendations for bone dose
(500 millirem per year) and 3 percent of their recommendations
[p. 12]
for whole-body dose (170 millirem per year). The presence of
Nuclear Fuel Services, based on data presently available, did not
-------
GUIDELINES AND REPORTS 1377
significantly increase the radiation dose to the "typical individual"
in 1968 above that due to fallout and natural radiation.
The "maximum individual" was assumed to obtain half his ra-
dionuclide intake from a diet containing maximum amounts of
specific radionuclides as well as ingesting 50 kg of deer meat and
40 kg of fish per year. For the "maximum individual" the first
year dose following ingestion is 38 millirem to the bone from 90Sr
or 3 percent of the AEC Regulations.5 The whole-body dose from
ingestion of 137Cs and 13lCs (mostly from deer meat) is 257 milli-
rem or 50 percent of the AEC Regulations. These data suggest
that in order not to exceed the AEC Regulations deer meat intake
be limited to 100 kg per year. Preliminary data indicate that the
external gamma dose above natural background is approximately
1.2 millirem per year to the "maximum individual."
The dose from 3H to a "maximum individual" was 2 millirem
while that to the "typical individual" around NFS was negligible.
The whole-body dose from 8SKr in air to a "maximum individual"
was 0.3 millirem and that to the "typical individual" 0.05 millirem.
Comparisons of dose commitments to FRC recommendations and
AEC Regulations raise questions concerning the existence of the
hypothetical "typical" and "maximum" individuals, the size of the
population at risk fitting these categories, and the suitability of
using established guidelines for comparison purposes, especially
when population groups are ill defined. These questions, together
with knowledge about dietary and living habits of populations at
risk, require a more definitive dose study than has already been
attempted.
RECOMMENDATIONS
A. Population dose study
The purpose of this study would be to realistically define existent
population groups on the bases of geographic location, occupation,
age, and ethnic and/or cultural differences; and to determine the
actual radiation dose to these populations:
1. Define in terms of size and location specific populations at risk.
[p. 13]
2. Determine the intake of radionuclides (90Sr, 137Cs and 131Cs) to these
populations by means of "market basket," "home sampling," and "institu-
tional diet sampling."
3. Determine doses from 129I by analysis of milk samples.
4. Based on the results of the dietary studies, carry out whole-body count-
ing (particularly for 137Cs and 134Cs) of selected individuals.
6 As they relate to a maximum exposed individual.
-------
1378 LEGAL COMPILATION—RADIATION
5. Determine the feasibility of a bioassay program for determination of
3H, 90Sr, and ^Pu in populations around NFS.
6. Determine the radionuclide content of selected human tissues in the
above population groups (upon autopsy if and when samples become
available).
7. Establish control groups in the Boston area (or other) and simultane-
ously perform the above enviromental sampling and bioassay procedures.
B. Continuous monitoring of the external environment around
NFS by means of field samplers
The purpose of this study would be to establish mean and max-
imum levels of marker radionuclides (85Kr in the air environment,
137Cs, n°Sr, and 3H in the aqueous environment) by continuous field
monitoring. Studies during FY 70 were done to establish that
these specific radionuclides are of dosimetric importance. Investi-
gations of the feasibility of field samplers now make it possible to
continuously, automatically monitor the air environment and/or
sample the aqueous environment.
1. Establish a suitable number of automatic continuously monitoring
85Kr air stations in the area of NFS. In addition, in the predominate wind
direction establish an automatic monitor for 3H.
2. Obtain a suitable monthly particulate stack air sample for 3H.
3. Establish a suitable number of automatic weir and ion exchange type
stream samplers at pertinent locations. These to be collected monthly and
the appropriate analysis performed.
4. Relate time release versus location versus concentration for the marker
radionuclides in the two environmental media.
C. Radionuclide levels in wildlife
The purpose of this study is to investigate the maximum and
average levels of dosimetrically important radionuclides in wildlife
and fish commonly hunted and ingested around NFS and to estab-
lish their radionuclide levels in relation to their range from NFS.
[P. 14]
1. Establish which game is important around NFS, the range of this
game, and the size of the human population at risk from ingestion of wildlife
and fish.
2. Establish proper sampling at various distances from .NFS in the forest
and stream environments.
3. Perform radionuclide determination for 13"Cs, 134Cs, i°sRu-Rh, and 90Sr
on the edible portions of wildlife game and fish.
4. Establish the size of human population at risk to this type of exposure
and the degree of exposure.
The duration of the above studies is estimated to be 2 years after
initiation. Completion of an in-depth population dose study, a
continuous field monitoring environmental program, and a radio-
nuclide level in game evaluation should more properly define the
-------
GUIDELINES AND REPORTS 1379
actual and potential human radiation doses due to operation of a
nuclear fuel reprocessing plant.
[P. 15]
REFERENCES
(1) NEW YORK STATE DEPARTMENT OF HEALTH. Environmental
radioactivity in New York State, quarterly and annual reports (1965 to
present).
(2) PELLETIER, C. A., SILL, C. W. and VOELZ, G. L. Environmental
Survey for the Nuclear Fuel Services, Incorporated Reprocessing Plant,
West Valley, New York, Health Services Laboratory, Idaho Operations
Office, USAEC (April 1968 to April 1969).
(3) NEW YORK STATE DEPARTMENT OF HEALTH, Albany, New
York. Environmental radioactivity in New York State, Annual Report
(1968).
(4) MANCHESTER, A. V., GABAY, J. J. and SAX, N. I. Tritiated mois-
ture in the atmosphere surrounding a nuclear fuel reprocessing plant.
Radiol Health Data, 9:341 (July 1968).
(5) SAX, N. I., REEVES, R. R., and DENNY, J. D. Surveillance for
krypton-85 in the atmosphere, Radiol Health Data, 10:15 (March 1969).
(6) NORTHEASTERN RADIOLOGICAL HEALTH LABORATORY. Proj-
ect, Environmental surveillance around nuclear facilities, Environmental
Radiation Activities, NERHL, Winchester, Mass. (1969-1970).
(7) SHLEIEN, B. An evaluation of internal radiation exposure based on
dose commitments from radionuclides in milk, food, and air. Health Phys-
ics 18:267 (1970).
(8) BATTELLE NORTHWEST. Evaluation of radiological conditions in
the vicinity of Hanford, January-June 1968, BNWL-1135 (August 1969).
(9) CLARK, F. et al., USDA Bulletin No. 127 and No. 132, US Dept. of
Agriculture (October 1954 and 1955).
(10) BUSTAD, L., and TERRY, J. L. Basic anatomical dietary and physio-
logical data for radiological calculations, HW-41638, General Electric
Company, Richland, Washington (February 1956).
(11) BUTLER, G. C. and VELD, A. Evaluation of radiation exposure from
internal deposition of three bone-seeking radionuclides, Health Physics,
13:916 (1967).
[p. 17]
(12) COWSER, K. E., KAYE, S. V., ROHWER, P. S., SNYDER, W. S. and
STRUXNESS, E. G. Dose estimation studies related to proposed con-
struction of an Atlantic-Pacific Interoceanic Canal with nuclear explosives:
Phase I, ORNL-4101, Oak Ridg-e National Laboratories, Oak Ridge, Ten-
nessee (1967).
(13) INTERNATIONAL COMMISSION ON RADIATION PROTECTION.
Report of Committee II on Permissible Dose for Internal Radiation, Perga-
mon Press (1959).
-------
1380 LEGAL COMPILATION—RADIATION
(14) COWSER, K. E. and TADMOR, J. Krypton-85 and tritium in an
expanding world nuclear power economy, in Health Physics Div. annual
progress report for period ending July 31, 1968 ORNL-4316, Oak Ridge
National Laboratories, Oak Ridge, Tenn. (1968).
(15) RIVERA, J. Strontium-90 in the diet during 1968 and projected levels
for 1969. Health and Safety Laboratory Report HASL-207, USAEC, New
York (April 1969).
(16) GUSTAFSON, P. F. and MILLER, J. F. The significance of "'Cs in
man and his diet. Health and Safety Laboratory Report HASL-184,
USAEC, New York (January 1968).
(17) WEAVER, C. L. A proposed radioactivity concentration guide for
shellfish. Radiol Health Data, 8:491 (September 1967).
(18) ANDERSON, K. D., New York State Department of Health. Personal
communication. Average of 15 measurements on 9/16/69, 9/23/69, and
10/16/69.
(19) FEDERAL RADIATION COUNCIL. Radiation Protection Guidance
for Federal Agencies, Federal Register (September 13, 1961).
(20) UNITED NATION SCIENTIFIC COMMITTEE ON THE EFFECTS
OF ATOMIC RADIATION report, Supplement No. 17 (A/3838), New
York (1958).
(21) KELLEHER, W. J. Environmental surveillance around a nuclear
fuel reprocessing installation, 1965-1S67, Radiol Data and Reports (August
1969).
(22) U.S. ATOMIC ENERGY COMMISSION, Title 10, CRF, Part 20-Stand-
ards for protection against radiation, Washington, D.C. 20545
[p. 18]
(23) EISENBUD, M. Nuclear reactors and the radioactive environment.
Presented at the American Association for the Advancement of Science,
134th Meeting, Boston, Mass. (December 28, 1969).
(24) NUCLEAR FUEL SERVICES, INC. Safety analysis, spent fuel
processing plant (July 1962).
(25) ANDERSON, K. D., New York State Department of Health, Personal
communication (March 30, 1970).
[p. 19]
4.2e LIQUID WASTE EFFLUENTS FROM A NUCLEAR
FUEL REPROCESSING PLANT, DEPARTMENT OF HEALTH,
EDUCATION, AND WELFARE, NOVEMBER 1970
FOREWORD
The recent growth in the utilization of nuclear reactors for
electrical generating plants has brought with it the need for nu-
-------
GUIDELINES AND REPORTS 1381
clear reprocessing plants that extract usable uranium and plu-
tonium from spent fuel elements. The Bureau of Radiological
Health performs a technical review and evaluation of the public
health factors of all nuclear facilities and provides technical as-
sistance to State health departments responsible for assessing
population exposure and radiation levels in the environment. The
Northeastern Radiological Health Laboratory under the aegis of
the Division of Environmental Radiation has undertaken an en-
vironmental survey of the first commercial operating fuel reproces-
sing plant in the United States.
The technical report series of the Bureau's regional laboratories
and its Division of Environmental Radiation is used to publish the
results of research projects and technical evaluations of nuclear
facilities. These reports are distributed to State and local ra-
diological health program personnel, Bureau technical staff, Bu-
reau advisory committee members, radiation safety officers,
libraries and information services, industry, the press, and other
interested individuals. These reports are also included in the
collections of the Library of Congress and the National Technical
Information Service.
I encourage the readers of these reports to inform the Bureau of
any omissions or errors. Your additional comments or requests
for further information are also solicited.
JOHN C. VlLLFORTH, Director,
Bureau of Radiological Health.
[p. iii]
PREFACE
The projected increase in the utilization of nuclear power for
electrical generating plants has resulted in both State and Federal
public health agencies placing increased program emphasis on the
surveillance of nuclear power plants. The Bureau of Radiological
Health provides recommended nuclear facility surveillance pro-
gram information for the guidance of health agencies. In order
to provide a better technical basis for environmental surveillance
recommendations, a series of field studies have been conducted at
operating nuclear facilities to obtain better data on radionuclides
in plant effluents and their subsequent distribution in the en-
vironment.
-------
1382 LEGAL COMPILATION—RADIATION
This field study around the Nation's first commercial nuclear
fuel reprocessing plant was for the purpose of identifying the
movement of critical radionuclides through the atmospheric and
aqueous environments in relationship to the fuel reprocessing
procedures. Technical data obtained from this study will be used
to: (1) develop minimum and optimum requirements for environ-
mental surveillance around nuclear fuel reprocessing plants, (2)
designate the radionuclides and environmental pathways of great-
est dosimetric significance, and (3) provide estimates and meas-
urements of the radiation dose to populations in the area of a
facility.
CHARLES L. WEAVER, Director,
Division of Environmental Radiation.
MORGAN S. SEAL, Director,
Northeastern Radiological Health Laboratory.
[p. v]
CONTENTS
Page
Foreword iii
Preface v
Abstract xi
Acknowledgment xii
Introduction 1
Plant location and liquid waste discharge practices 2
Sampling Locations 3
Liquid waste discharges 5
Samples collected 5
Measurements and results 7
Activity discharged from plant to interceptor tanks 8
Activity discharged from lagoon-3 to aqueous environment 15
Activity deposited in lagoon system 22
Distribution of radionuclides between dissolved
and suspended solids 23
Relationship of stream concentrations to lagoon-3 discharges 26
Samples collected 26
Measurements and results 26
Stream and discharge variables 30
Data evaluation 31
Absorption of radionuclides by stream 32
Comparison of the concentrations of radionuelides in cattaraugus
creek with the 10GFR20 discharge concentration limits 35
Radionuclides in bottom sediment from buttermilk
and cattaraugus creeks 36
Samples collected 36
Measurements and results 36
Data evaluation 36
Summary 38
Recommendations 39
-------
GUIDELINES AND REPORTS 1383
Page
References 41
Appendices
I. Photographs of Collection Sites ...
II. Gamma and Alpha Spectra from Interceptor . , .
Composite 5/21-8/4/69 ublication
III. Procedures Used for Radionuclide Measurements
[p. vii]
TABLES
Page
1. Sampling sites used for characterization of liquid
waste from Nuclear Fuel Services 5
2. Composite liquid waste effluent samples from Nuclear
Fuel Services—1969 6
3. Fuel processing information for periods covered by
interceptor composites—1969 6
4. Nuclear Fuel Services liquid effluent samples—1969
Results of qualitative gamma analyses 9
5. Nuclear Fuel Services liquid effluent sample—interceptor
composite 4/1-5/21/69 10
6. Nuclear Fuel Services liquid effluent sample—interceptor
composite 5/21-8/4/69 11
7. Nuclear Fuel Services liquid effluent sample—interceptor
composite 8/18-9/14/69 12
8. Relative contributions of individual radionuclides to the
beta activity of the interceptor composites 13
9. Relative contributions of individual radionuclides to the
alpha activity of the interceptor composites 14
10. Relative contributions of individual radionuclides to the
beta activity of lagoon-3 composites—May-October 1969 15
11. Nuclear Fuel Services liquid effluent sample—lagoon-3
composite May 1969 16
12. Nuclear Fuel Services liquid effluent sample—Iagoon-3
composite June 1969 17
13. Nuclear Fuel Services liquid effluent sample—lagoon-3
composite July 1969 18
14. Nuclear Fuel Services liquid effluent sample—lagoon-3
composite August 1969 19
15. Nuclear Fuel Services liquid effluent sample—lagoon-3
composite September 1969 20
16. Nuclear Fuel Services liquid e'ffluent sample—lagoon-3
composite October 1969 21
17. Comparison.of activities discharged from plant with those
discharged to aqueous environment 24
18. Distribution of radionuclides between dissolved and
suspended solid in water discharged from Lagoon-3
May-October 1969 25
19. Radionuclide concentrations in Buttermilk and
Cattaraugus Creeks June 17 and 18, 1969 27
-------
1384 LEGAL COMPILATION—KADIATION
20. Radionuclide concentrations in Buttermilk and
Cattaraugus Creeks November 4 and 5,1969 28
21. Uranium and plutonium concentrations in the
Buttermilk Creek on June 17 and November 4, 1969 29
22. Radionuclides contributing to beta activity of
Buttermilk and Cattaraugus Creeks 31
23. Effective Dilution Factors for radionuclides in Buttermilk
and Cattaraugus Creeks June 17, 18 and November 4, 1969 33
[p. viii]
24. Stream Absorption Factors for radionuclides in Buttermilk
and Cattaraugus Creeks June 17,18 and November 4,1969 34
25. Relative amounts of activity removed from water in passage
from lagoon-3 to Cattaraugus Creek 34
26. Fractions of 10CFR20 discharge concentration limits in
Cattaraugus Creek for individual radionuclides 35
27. Radionuclide concentrations in bottom sediments from
Buttermilk and Cattaraugus Creeks 37
FIGURES
1. Sample collection locations on lagoon and stream systems 4
2. Photograph of interceptor tanks—collection site 1 43
3. Photograph of lagoon-1 43
4. Photograph of lagoon-2 44
5. Photograph of lagoon-3 44
6. Photograph of lagoon-3 weir—collection site 2 45
7. Photograph of Buttermilk Creek—collection site 5 45
8. Photograph of confluence of Buttermilk and Cattaraugus
Creeks—collection site 6 46
9. Photograph of Cattaraugus Creek—collection site 8 46
10. Gamma spectrum of dissolved solids from interceptor
composite 5/21-8/4/69—0-2000KeV 48
11. Gamma spectrum of dissolved solids from interceptor composite
5/21-8/4/69 with ruthenium and cesium removed—0-700 KeV 49
12. Gamma spectrum of dissolved solids from interceptor composite
5/21-8/4/69 with ruthenium and cesium removed—600-1400 KeV .. 50
13. Gamma spectrum of suspended solids from interceptor composite
5/21-8/4/69—0-2000 KeV 51
14. Gamma spectrum of suspended solids from interceptor composite
5/21-8/4/69 with ruthenium and cesium removed—0-300 KeV 52
15. Gamma spectrum of suspended solids from interceptor composite
5/21-8/4/69 with ruthenium and cesium removed—0-700 KeV 53
16. Gamma spectrum of suspended solids from interceptor composite
5/21-8/4/69 with ruthenium and cesium removed—600-1400 KeV . . 54
17. Alpha spectrum of suspended solids from interceptor
composite 5/21-8/4/69 without chemical separation 55
18. Alpha spectrum of uranium separated from dissolved solids
from interceptor composite 5/21-8/4/69 56
19. Alpha spectrum of plutonium separated from suspended
solids from interceptor composite 5/21-8/4/69 57
-------
GUIDELINES AND REPORTS 1385
ABSTRACT
The liquid waste effluents from Nuclear Fuel Services were studied in detail
during a six-month period May through October 1969. The concentrations and
amounts of individual radionuclides discharged from the plant were measured
and the amounts of sedimentation of individual radionuclides in the lagoon
system were estimated.
Tritium, ruthenium-106, strontium-90, cesium-137 and cesium-134 were the
principal radionuclides discharged to the environment during this period. No
relationship could be established between the amount and burnup of fuel proc-
essed and the amount of activity discharged from the plant to the lagoon sys-
tem during this study. For the Yankee fuel campaign of May-August 1969, the
waste management practice and not the amount of fuel processed was the con-
trolling factor in the amount of activity discharged from the plant to the
lagoon system.
During June and November 1969 simultaneous sampling was carried out
at the point of discharge of the waste and several locations on the Buttermilk
and Cattaraugus Creeks. Tritium, ruthenium-106, and strontium-90 were the
radionuclides present in the highest concentrations in these streams during
these periods. Stream dilution and absorption factors were calculated for indi-
vidual radionuclides at various locations along the stream system. A compari-
son of the concentrations of the radionuclides in Cattaraugus Creek with
10CFR20 discharge concentration limits showed that strontium-90 was about
20 percent of the concentration limit during both sampling periods. All other
radionuclides were less than 10 percent of the concentration limits during these
periods.
The mention of commercial products, their source, or their use in connection with material
reported herein is not to be construed as either an actual or implied endorsement of such products
by the Department of Health, Education, and Welfare, Public Health Service.
[p. xi]
ACKNOWLEDGEMENT
The assistance of the following individuals in planning and initiating this
study is gratefully acknowledged.
Bernard Shleien Chief, Environmental Radiation Branch, Northeastern
Radiological Health Laboratory.
James E. Martin .... Deputy Chief, Nuclear Facilities Branch Division of En-
vironmental Radiation Bureau of Radiological Health.
Charles L. Weaver . . Director, Division of Environmental Radiation Bureau
of Radiological Health.
Thomas Cashman ... Director, Nuclear Engineering and Surveillance N.Y.
State Dept. of Environmental Conservation.
Kurt Anderson Senior Sanitary Engineer, Nuclear Engineering and
Surveillance N.Y. State Dept. of Environmental Con-
servation.
Richard B. Keely Safety and Industrial Relations Manager Nuclear Fuel
Services, Inc.
The authors also wish to acknowledge the contributions made to this study
by the following members of the staff of the Northeastern Radiological Health
Laboratory.
-------
1386 LEGAL COMPILATION—RADIATION
Emilio Troianello Paul Groulx
James Murphy Ella Peers
Richard Kramkowski Dorothy Bowen
Alvis Jordans Harrington Lumsden
George Burns Alexander Ferragamo
[P- xii]
LIQUID WASTE EFFLUENTS FROM A NUCLEAR FUEL
REPROCESSING PLANT
INTRODUCTION
Increase in the use and number of nuclear reactors has brought
with it the need for nuclear fuel reprocessing plants that extract
usable uranium and plutonium from spent fuel elements. Pre-
sently, one commercial plant, Nuclear Fuel Services, Inc., is in
operation in western New York, a second plant is under con-
struction in Illinois, and others are being planned. The fact that
such plants discharge radionuclides to the environment necessi-
tates surveillance around the plant in order to determine the
quantity and composition of waste-discharge, the effect of such
discharge on the environment where it accumulates, and the level
of radiation dose delivered to surrounding populations.
Nuclear Fuel Services, Inc., began processing fuel in April 1966.
Since 1964, the New York State Department of Health has con-
ducted an extensive environmental surveillance program around
this plant (1). The Atomic Energy Commission (2) and Nuclear
Fuel Services (3) also conduct environmental surveillance pro-
grams around the plant site.
The Bureau of Radiological Health has a responsibility to pro-
vide guidance to state and local health agencies in developing
surveillance programs for nuclear facilities including fuel reproc-
essing plants. In order to meet this responsibility, the Bureau of
Radiological Health, in cooperation with the New York State
Department of Health, the Atomic Energy Commission, and Nu-
clear Fuel Services, began in 1969 a special study of the Nuclear
Fuel Services plant and its environs for the purpose of deter-
mining the requirements of environmental surveillance programs
for such plants.
The objectives of this study are:
(1) To develop minimum and optimum requirements for environmental
surveillance programs around nuclear fuel reprocessing plants.
(2) To designate the radionuclides and environmental pathways of greatest
dosimetric significance.
(3) To provide methods for estimating the radiation dose to the populations
in the area of a facility.
-------
GUIDELINES AND REPORTS 1387
This report presents the results of that part of the study con-
cerned with the liquid waste effluents discharged from Nuclear
Fuel Services and includes the following information:
[p. 1]
(1) Identification of radionuclides discharged from the plant.
(2) Measurements of radiomiclide concentrations and total activities dis-
charged in the dissolved (soluble) and suspended (insoluble) liquid
effluent fractions.
(3) The influence of the type, age, and amount of fuel processed on the
amount of activity discharged.
(4) Determination of the relationship between the concentrations of various
radionuclides discharged from the plant and subsequent levels at various
locations in the aqueous environment.
(5) Measurements of concentrations of radionuclides in bottom sediments
from the aqueous environment.
PLANT LOCATION AND LIQUID WASTE DISCHARGE PRACTICES
Nuclear Fuel Services, Inc., operates the nation's first commer-
cial nuclear fuel reprocessing plant on the 3,300 acre site of
Western New York Nuclear Service Center located in the town of
Ashford, Cattaraugus County, New York. This site is located 30
miles southeast of Buffalo and about 4 miles south of Springville.
This plant operates under license CSF-1 issued by the U.S. Atomic
Energy Commission. The process employed is a chop, leach, and
Purex-solvent extraction procedure and the plant capacity is esti-
mated to be one metric ton of uranium per day (4).
The high level liquid waste from plant operations is concentrated
and stored in a multiple contained, underground, tank farm. Low
level waste generated from evaporator condensates, plant floor
drains, laundry and decontamination operations is discharged into
interceptor tanks and then to a series of three holding ponds or
lagoons prior to discharge into the aqueous environment. Figure
1 is a diagram showing the lagoon and stream systems into which
the low level wastes are discharged. There are two interceptor
tanks each with a 22,000 gallon capacity. Technical specification
4.2.1 of license CSF-1 states that in any calendar quarter no more
than 48 curies of combined equivalent unidentified alpha and beta
activity, other than tritium or iodine-131, shall be transferred to
the lagoons and that the concentration of the waste discharged
shall be less than 5 X 10~3 /tCi/ml. When the combined gross al-
pha and beta activities in an interceptor tank are less than 5 X
1Q-3 ^Ci/ml, then the waste is neutralized using sodium hydroxide
[P. 2]
and bottom drained by gravity to lagoon-1. If the activity level
exceeds the above concentration, then the waste is either diluted
-------
1388 LEGAL COMPILATION-—RADIATION
to the desired concentration or returned to the plant for further
processing. Photographs of the interceptor tanks, lagoons, and
weir are presented in Appendix I.
The lagoons accept the transfers from the interceptor tanks and
provide time for precipitation and sedimentation of insolubles.
Lagoon-1 has a capacity of 300,000 gallons and a continuous high
level overflow into lagoon-2. Lagoon-2 has a 2,300,000 gallon
capacity and is drained into lagoon-3 through a valved line 18
inches from the bottom of the lagoon. Lagoon-3 has a 2,500,000
gallon capacity and the waste is discharged to the aqueous en-
vironment through a flow metering system. The valved drain
line from lagoon-3 is 3 feet from the bottom. The waste manage-
ment practice is to close off the drain line from lagoon-3 when
lagoon-2 is drained into lagoon-3, and to shut off the drain line
from lagoon-2 when waste is being discharged from lagoon-3.
The waste from lagoon-3 is discharged into Erdman's Brook
which flows into Frank's Creek which flows into Buttermilk Creek.
The Buttermilk Creek flows into Cattaraugus Creek which even-
tually empties into Lake Erie. As shown in figure 1, the entire
route to Cattaraugus Creek including the confluence of the Butter-
milk and Cattaraugus Creeks is on NFS leased property and is a
posted restricted area. The rate of discharge from lagoon-3 is
controlled in proportion to the Cattaraugus Creek flow to keep the
concentrations in Cattaraugus Creek below the established limits.
Technical specification 4.2.2 states that "Activity released to Cat-
taraugus Creek from all sources on the site shall not at any time
result in a concentration, as measured at the monitoring station in
Cattaraugus Creek, which exceeds twice the concentration specified
in Title 10 Code of Federal Regulations Part 20; provided however,
that in any 365 consecutive day period, the average concentration
of radioactivity in Cattaraugus Creek shall not exceed that speci-
fied in Title 10 Code of Federal Regulations Part 20."
Sampling Locations
The sampling locations used in this study are identified by num-
ber in figure 1. A list of the sampling locations used, their identi-
fication numbers, and their distance from lagoon-3 measured along
the streams is presented in table 1. Photographs of the collection
sites nos. 5, 6, and 8 are presented in Appendix I.
[p. 3]
-------
GUIDELINES AND REPORTS
1389
SCALE
FIGURE 1.—Sample collection locations on lagoons and stream systems.
TABLE 1. SAMPLING SITES USED FOR CHARACTERIZATION OF LIQUID WASTE FROM NUCLEAR FUEL SERVICES
Location
Interceptor tank
Confluence of Frank's and Buttermilk Creeks
Bridge at Bond Road
Bridge at Thomas Corners Road
Confluence of Buttermilk and Cattaraugus Creeks
Felton Bridge
Springville Dam
Buttermilk Road
Bigelow Bridge
Site identification
number
1
2
3
4
5
6
7
8
0
00
Distance from
lagoon-3 (miles)
1.1
2.0
3.3
3.5
4.V
6.1
1.8
23
(upstream
of site #3)
(upstream
of site #6)
-------
1390 LEGAL COMPILATION—RADIATION
LIQUID WASTE DISCHARGES
Samples Collected
For the purpose of defining liquid waste discharges from the
plant, three composite interceptor and six composite lagoon sam-
ples were supplied by Nuclear Fuel Services during 1969. The
interceptor composites represented waste discharged from the
plant to the lagoon system. The lagoon composites represented
waste discharged from the lagoon system to the aqueous environ-
ment. The interceptor samples represented time periods covering
a fuel campaign,1 while the lagoon samples were all monthly com-
posites. From the volume of liquid waste represented by a com-
posite, the total activity discharged either from the plant or from
the lagoons for a given period could be calculated. Information
on these composite samples is presented in table 2 and fuel proc-
essing information for the campaign periods covered by the inter-
ceptor composites is presented in table 3.
[p. 5]
TABLE 2. COMPOSITE LIQUID WASTE EFFLUENT SAMPLES FROM NUCLEAR FUEL SERVICES—1969
Sample
site
1
1
1
2
2
2
2
2
2
i Description
Interceptor-A 4/1 to 5/21 .
Interceptor-B 5/21 to 8/4
Interceptor C 8/18 to 9/14 .
Lagoon-3 May
Lagoon-3 June
PH
>7
>7
1
11
11
11
11
7
8
1 ml
1 ml
1 ml
1 ml
1 ml
1 ml
1 ml
1 ml
1 ml
Volume
equivalent
— 30 000 gal
— 2000 gal
— 1000 gal
— 1000 gal
— 1000 gal
— 1000 gal
— looo gal
— 1000 gal
— 1000 gal
Total volume
represented
(gallons)
.. 2.60 X 10'
4 27 X 10«
1.91 X 10'
1.73 X 10'
3.68 X 10'
3.62 X 10'
2 85 X 10'
3.99 X 10'
3.25 X 10'
TABLE 3. FUEL PROCESSING INFORMATION FOR PERIODS COVERED BY INTERCEPTOR COMPOSITES—1969
Process Dates
2/17-4/1 4/1-5/10 5/24-7/9 8/18-9/21
Campaign
Fuel burnup MWD/MTU'
Enrichment 2JSU
Amount of fuel processed MTU
NPR2
April 1968
2500
0.7%
28
NPR
April 1968
2500
0.7%
21
Yankee3
March 1968
20,000
4.9%
20
NPR
No irradiation
0
0.7%
30
1 MWD/MTU = Megawatt days per metric tonne of uranium.
1 New Production Reactor, a plutomum production reactor at Hanford, Wash.
3 Yankee Nuclear Power Station, a 600 megawatt pressurized water reactor at Rowe, Mass.
[p. 6]
1 A campaign is a processing run on a specific fuel including cleanout and turnaround of the
plant in preparation for the next campaign.
-------
GUIDELINES AND REPORTS 1391
Dates indicated in table 3 represent the periods during which
the processing of the fuel was begun. Interceptor-A was col-
lected as representative of waste originating from an NPR cam-
paign, and interceptor-B was collected as representative of waste
originating from a Yankee campaign. It should be noted, however,
that as far as the low level liquid wastes are concerned, no line
can be drawn indicating the end of one campaign and the begin-
ning of another. Some overlapping is unavoidable due to the
nature of the operation. Since the campaign of 8/18 to 9/14
involved unirradiated fuel, the waste represented by the composite
for that period (interceptor-C) most likely originated from ac-
tivities left over from the Yankee campaign.
Measurements and Results
These composite effluent samples were separated into dissolved
and suspended solids fractions by filtration through an 0.45 ju
membrane filter and each of these fractions analyzed separately.2
Gamma spectrometry using a Ge(Li) detector was used to
identify the presence of gamma emitting radionuclides in these
samples. The dissolved and suspended solids fractions from each
sample were analyzed covering an energy range of 0-2000 KeV.
Following the removal of the radionuclides of ruthenium and ce-
sium (the principal gamma emitting radionuclides present), these
samples, with the exception of interceptor-A and lagoon-3 May,
were subjected to additional Ge(Li) qualitative analyses.
Table 4 lists the gamma emitting radionuclides identified in each
of the fractions of these samples. The radionuclides are listed in
order of decreasing estimated concentrations.
The gamma emitting radionuclides identified in the interceptor
composites were essentially the same for the Yankee and NPR
campaigns. Interceptor composites B and C showed small but
detectable quantities of europium-154, europium-155 and manga-
nese-54. These radionuclides were not identified in interceptor-A,
but this was probably due to a difference in the sensitivity of the
measurements resulting from a smaller size sample (see table 2).
The lagoon-3 composites for the 6-month period May through
October 1969 all contained essentially the same identifiable gamma
[p. 7]
emitting radionuclides. Radionuclides were identified in the dis-
solved solids fractions of interceptor-C which were not present in
the dissolved solids fractions of the other composite effluent sam-
- This separation took place several months after collection of the sample. It was determined
that this storage period did not significantly alter the distribution of activity between the dis-
solved and suspended solids fractions.
-------
1392 LEGAL COMPILATION—RADIATION
pies. This resulted from the sample being acid (pH = 1.0). The
aliquots used to make up the composite were collected from the
interceptor tanks prior to the neutralization of the waste. All
other composite effluent samples were basic (pH = > 7), having
been collected after neutralization of the waste.
Quantitative analyses on these composite samples were carried
out for gross alpha, gross beta, tritium, ruthenium-106, cesium-
137, cesium-134, cerium-144, zirconium-95, cobalt-60, manganese-
54, strontium-90, promethium-147, plutonium-238, plutonium-239,
plutonium-241, uranium-232, uranium-234, and uranium-238. In
addition, americium-241, curium-242, and curium-244 were meas-
ured in the interceptor composites only. The results of these
measurements for the interceptor samples are presented in tables
5-7 and for the lagoon-3 samples in tables 11-16. The total ac-
tivity in curies, represented by the composite, for each of the ra-
dionuclid.es, is also presented in these tables. All activities were
corrected for decay to the midpoint of the collection period except
for the gross alpha and beta activities 3 for which no decay cor-
rection was applied. It should also be noted that the gross beta
measurements do not include tritium and because of self-absorp-
tion effects soft beta activities will not contribute substantially to
the gross beta measurement.
Examples of the alpha and gamma spectra obtained during the
analyses of these samples are presented in Appendix II. A brief
description of the procedures used in the analyses of these samples
is presented in Appendix III.
Activity Discharged from Plant to Interceptor Tanks
Tritium was the principal radionuclide being discharged from
the plant to the interceptor tanks. During the period covered by
interceptor composites B and C,4 820 curies of tritium were dis-
charged from the plant and this was 13 times more than any other
radionuclide.
;: The gross alpha and beta measurements were made about 2 months after collection of the
samples.
4 Due to analytical difficulties nH was not measured in Interceptor-A.
[p. 8]
-------
GUIDELINES AND KEPORTS
1393
I
s
h-
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5 I S S S
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-------
1394
LEGAL COMPILATION—RADIATION
TABLE 5. NUCLEAR FUEL SERVICES LIQUID EFFLUENT SAMPLE—INTERCEPTOR COMPOSITE 4/1-5/21/69
Radionuclide
Microcuries per milliliter Curies discharged
Total Dissolved Suspended
Gross a
Gross /}
>H
IWRy
«'Cs
mc$
»Sr
i«Ce
'"Pm
«Zr
«Co
i»Sb
**ln
JMPU
»H>u
wpu
JMU
J34(J
3»U
»'Am
M'Cm
«H
"*Ru
"'Cs
mcs
»Sr
n«ce
'"Pm
«2r
"Co
'»Sb
«Mn
23Spu
*»Pu
*'Pu
MJU
IMU
»«U
"'Am
»JCm
w«Cm
Solids (mg/1)
6.2X10-
5.9X10-
4.8X10-
3.7X10-
4.4X10-
1.9X10-
2.3X10-
4.8X10-
2.5X10-
3.3X10-
1.4X10-
1.2X10-
3.7X10-
1.1 X 10-
3.1X10-
1.3X10-
6.6X10-
3.2X10-
4.8X10-
9.1X10-
2.8X10-
0.1X10-
2.1X10-
4.8X10-
1.1X10-
4.0X10-
1.7X10-
2.0X10-
<3X10-
<1X10-
-------
GUIDELINES AND REPORTS
1395
TABLE 7. NUCLEAR FUEL SERVICES LIQUID EFFLUENT SAMPLE—INTERCEPTOR COMPOSITE 8/18-9/14/69
Radionuclide
Microcuries per milliliter
Curies discharged
Gross o
Gross /?
'H
"«Ru
"'Cs
'"Cs
"Sr
i«Ce
»'Pm
«Zr
"Co
mSb
"Mn
23apu
23»pu
2
-------
1396 LEGAL COMPILATION—RADIATION
Fifty-three percent of the alpha activity discharged from the
plant during the period covered by the interceptor composites was
due to radionuclides of plutonium. Curium-242, eurium-244, and
americium-241 were the other major contributors to the alpha
activity. Radionuclides of uranium contributed only about 2.5
percent of the alpha activity. The relative contributions of the
various radionuclides to the total alpha activity of the three inter-
ceptor composites are presented in table 9.
TABLE 9. RELATIVE CONTRIBUTIONS OF INDIVIDUAL RADIONUCLIDES TO THE ALPHA ACTIVITY OF THE
INTERCEPTOR COMPOSITES
Radionuclide Percent of alpha activity'
2i«pu 16
M'PU 37
"'Am 11
3«Cm 28
*
-------
GUIDELINES AND REPORTS 1397
Activity Discharged from Lagoon-3 to Aqueous Environment
Tritium was the principal radionuclide being discharged to the
aqueous environment from lagoon-3 during the period May-
October 1969. Thirty-three times more tritium was discharged
during the period than any other radionuclide. Seventy-three
percent of the beta activity (exclusive of ^H) discharged during
this period was due to ruthenium-106. Strontium-90, cesium-137,
and cesium-134 were the other major contributors to the beta ac-
tivity. The activities due to cerium-144, promethium-147, zircon-
ium-95, cobalt-60, antimony-125, and manganese-54 were less than
two percent of the beta activity discharged. Listed in table 10
are the relative contributions of the various radionuclides to the
beta activity (exclusive of ;'H) of the lagoon-3 composites for
May-October 1969.
TABLE 10. RELATIVE CONTRIBUTIONS OF INDIVIDUAL RADIONUCLIDES TO THE BETA ACTIVITY OF LAGOON-3
COMPOSITES— MAY-OCTOBER 1S69
Radionuclide Percent of beta activity1
""Ru 73
»Sr 12
»'Cs 11
'"Cs 3
'«Ce 0.2
»'Pm 0.1
«Zr <0.1
"Co 0.3
'«Sb 0.8
»Mn
1 Relative contribution of the individual radionuclide to the sum total of the activities of those radio-
nuclides listed.
[p. 15]
-------
1398
LEGAL COMPILATION—RADIATION
TABLE 11. NUCLEAR FUEL SERVICES LIQUID EFFLUENT SAMPLE—LAGOON-3 COMPOSITE MAY 1969
Radionuclide
Gross a
Gross [',
»H
IMRU
»?CS
'"Cs
"Sr
'«Ce
I<7Pm
95Zr
«Co
i»Sb
*Mn
J3«PU
J»pu
»'Pu
JMJ
3"U
2»U
Solids(mg/l)
N.A.=No Analysis.
Total
2.2X10-
6.3X10-
4.3X10-
3.0X10-
9.6X10-
2.3X10-
7.3X10-
6.6X10-
4.4X10-
3.0X10-
1.3X10-
1.1X10-
6.0X10-
2.0X10-
3.2X10-
2.2X10-
8.4X10-
3.3X10-
4.4X10-
Microcunes per milliliter
Dissolved
1.7X10-'
4.3X10-*
4.3X10-'
2.6X10-'
4.6X10-S
1.1 X 10-5
1.7X10-*
<5X10-'
<3X10-'
<2X10-7
1.1X10-*
1.0X10-5
<5XlO-»
0.06 X 10-"
0.1X10-'
<3X10-'
7.8X10-'
3.1X10-'
4.1X10-8
5.4 X103
Suspended
0.5X10-
2.0X10-
N.A.
0.4X10-
5.0X10-
1.2X10-
5.6X10-
6.6X10-
4.4X10-
3.0X10-
0.2X10-
0.1X10-
6.0X10-
1.9XM-
3.1X10-
2.2X10-
0.6X10-
0.2X10-
0.3X10-
1.2X10'
Curies discharged
1.4X10-'
4.1
2.8 X102
2.0
6.3X10-
1.5X10-
4.8X10-
4.3X10-
2.9X10-
2.0X10-
8.5X10-
7.2X10-
3.9X10-
1.3X10-
2.1X10-
1.4X10-
5.5X10-
2.2X10-
2.9X10-
[p. 16]
TABLE 12. NUCLEAR FUEL SERVICES LIQUID EFFLUENT SAMPLE—LAGOON-3 COMPOSITE JUNE 1969
Radionuclide
Microcunes per milliliter Curies discharged
Total Dissolved Suspended
Gross a
Gross /3
'H
"»Ru
»'Cs
'"Cs
»Sr
i«Ce
i«Pm
"Zr
"Co
i»sb
"Mn
»»Pu
3»PU
s«ipu
2I2U
»«u
2»U
Solids (mg/1)
8.2X10-
1.4X10-
4,3X10-
1.1X10-
7.3X10-
2.3X10-
1.2X10-
1.6X10-
9.0X10-
4.1X10-
1.3X10-
6.8X10-
< 8X10-
9.7X10-
1.7X10-
7.0X10-
3.9X10-
1.5X10-
6.4X10-
1.3X10-
4.3X10-
1.0X10-
5.2X10-
1.6X10-
1.1 X 10-
< 5X10-
< 3X10-
< ixio-
1.2X10-
6.7X10-
<5X10-
1.7X10-
0.3X10-
< 3X10-
3.8X10-
1.4X10-
1.8X10-
0.1X10-
N.A.
0.1X10-
2.1X10-
0.7X10-
0.1X10-
1.6X10-
9.0X10-
4.1X10-
0.1 X 10-
0.1X10-
< 3X10-
8.0X10-
1.4X10-
7.0X10-
0.1 X 10-
0.05X10-
1.1X10-'
1.9X10'
6.0 XlO2
1.5X10'
1.0
3.2X10-'
1.7
2.2X10-'
1.3X10-'
5.7 XlO-4
1.8X10-'
9.5X10-'
< 1.1X10-'
1.3X10-*
2.4X10-*
9.7 X10-*
5.4X10-'
2.1X10-'
1.5X10- 1.4X10- 0.05X10- 2.1X10-*
3.8 XlO3 3.9X10'
N.A.=No Analysis.
[p. 17]
-------
GUIDELINES AND REPORTS
1399
TABLE 13. NUCLEAR FUEL SERVICES LIQUID EFFLUENT SAMPLE—LAGOON-3 COMPOSITE JULY 1969
Radionuclide
Microcuries per milliliter Curies discharged
Total Dissolved Suspended
Gross a
Gross /?
'H
IMRU
»'Cs
"«Cs
»Sr
'«Ce
147Pm
«Zr
"Co
'«Sb
»Mn
JMPU
2»PU
"ipu
2»U
2M(J
2«U
Solids (mg/1)
4.5X10-
1.5X10-
4.9X10-
1.2X10-
4.9X10-
1.2X10-
5.1X10-
3.8X10-
2.0X10-
7.0X10-
7.2X10-
5.4X10-
3.1X10-
1.4X10-
3.7X10-
2.6X10-
2.1X10-
8.0X10-
2.9X10-
1.3X10-
4.9X10-
1.1X10-
0.4X10-
0.1X10-
2.0X10-
<5X10-
<3X10-
< 1X10-
4.5X10-
5.1X10-
<5X10-
0.03X10-
0.07X10-
< 3X10-
1.5X10-
5.7X10-
1.6X10-
0.2X10-
N.A.
0.1 X 10-
4.5X10-
1.1X10-
3.1X10-
3.8X10-
2.0X10-
7.0X10-
2.7X10-
0.3X10-
3.1X10-
1.4X10-
3.6X10-
2.6X10-
0.6X10-
2.3X10-
6.2X10-'
2.1X10'
6.7X10'
1.6X10'
6.7X10-
1.6X10-
7.0X10-
5.2X10-
2.7X10-
9.6X10-
9.9X10-
7.4X10-
4.2X10-
1.9X10-
5.1X10-
3.6X10-
2.9X10-
i.ixio-
8.0X10- 5.2X10- 2.8X10- 1.1X10-
3X10' 0.4X10'
N.A.=No Analysis.
[p. 18]
TABLE 14. NUCLEAR FUEL SERVICES LIQUID EFFLUENT SAMPLE—LAGOON-3 COMPOSITE AUGUST 1969
Radionuclide
Microcuries per milliliter Curies discharged
Total Dissolved Suspended
Gross a
Gross /-:
'H
1MRU
"7CS
""Cs
»Sr
i«Ce
1<7Pm
«Zr
"Co
'»Sb
*Mn
23«PU
2»PU
241pU
232[J
2»U
M«U
Solids (mg/1)
6.4X10-
1.3X10-
2.9X10-
8.3X10-
6.3X10-
2.4X10-
1.9X10-
1.6X10-
8.0X10-
4.0X10-
7.3X10-
7.6X10-
< 8X10-
6.9X10-
6.7X10-
4.4X10-
2.9X10-
i.ixio-
4.5X10-
1.2X10-
2.9X10-
7.7X10-
4.0X10-
1.5X10-
1.9X10-
<5X10-
<3X10-
< 1X10-
7.2X10-
7.6X10-
<5X10-
0.7X10-
0.7X10-
< 3X10-
2.9X10-
1.1X10-
1.9X10-
0.1X10-
N.A.
0.6X10-
2.3X10-
0.9X10-
0.04X10-
1.6X10-
8.0X10-
4.0X10-
0.1 X 10-
0.04X10-
< 3X10-
6.2X10-
6.0X10-
4.4X10-
0.08X10-
0.04X10-
6.9X10-'
1.4X10'
3.1X10'
9.0
6.8X10-
2.6X10-
2.1
1.7X10-
8.6X10-
4.3X10-
7.9X10-
8.2X10-
<8.6X10-
7.5X10-
7.2X10-
4.8X10-
3.1X10-
1.2X10-
i.ixio- 1.1x10- < o.ixio- 1.2x10-
2.4X10' 2.1X10'
N.A.=No Analysis.
[p. 19]
-------
1400
LEGAL COMPILATION—RADIATION
TABLE 15. NUCLEAR FUEL SERVICES LIQUID EFFLUENT SAMPLE—LAGOON-3 COMPOSITE SEPTEMBER 1969
Radionuclide
Gross a
Gross ft
»H
IOSRU
i»Cs
1MCs
*>Sr
'«Ce
'"Pm
»Zr
"Co
i«sb
«Mn
Hipu
l»pu
«'Pu
JM(J
134\J
J»U
Solids (mg/1)
Total
4.4X10-'
8.7X10-'
5.1X10-*
3.8X10-'
1.5X10-'
3.7X10-5
1.2X10-<
<8X10-'
<6X10 '
< 1.5X10-'
4.0X10-'
4.5X10-'
1.0X10-'
3.2X10-'
3.6X10-'
<4X10-'
1.3X10-'
6.5X10-'
1.4X10-'
Microcuries per millihter Curies discharged
Dissolved Suspended
3.9X10-
8.4X10-
5.1X10-
3.7X10-
1.4X10-
3.4X10-
1.2X10-
<5X10-
<3X10-
< 1X10-
4.0X10-
4.5X10-
<5X10-
2.1X10-
2.5X10-
<3X10-
1.3X10-
6.5X10-
0.5X10-
0.3X10-
N.A.
0.09X10-
o.ixio-
0.3X10-
0.06X10-
<3X10-
<3X10-
<5X10-
0.04X10-
<4X10-
1.0X10-
1.1x10-
1.1X10-
< ixio-
0.07X10-
0.04X10-
6.6X10-'
1.3X10'
7.7X10'
5.7
2.3
5.6X10-'
1.8
< 1.2X10-
<9X10-
< 2.3X10-
6.0X10-
6.8X10-
1.5X10-
4.8X10-
5.4X10-
<6X10-
2.0X10-
9.8X10-
1.4X10- < 0.01X10- 2.1X10-
2.6X10' 2.2X10'
N.A.— No Analysis.
[p. 20]
TABLE 16. NUCLEAR FUEL SERVICES LIQUID EFFLUENT SAMPLE—LAGOON.3 COMPOSITE OCTOBER 1969
Radionuclide
Gross a
Gross p
>H
1MRU
»'Cs
»«Cs
»Sr
i«Ce
'"Pm
«Zr
"Co
iMSb
»Mn
mpu
JJ'PU
MIPU
J»U
»34(J
2»LI
Solids (mg/1)
Total
3.2x10-'
8.8X10-"
3.3X10-3
3.1X10-'
2.2X10-'
4.6X10-'
1.2X10-'
1.8X10-'
9.0X10-'
5.6X10-'
2.2 X 10-*
1.6X10-*
4.6X10-'
4.7X10-'
6.3X10-'
4.0X10-'
2.4X10-'
9.0X10-'
9.0X10-'
Microcuries per milliliter Curies discharged
Dissolved Suspended
3.1X10-
7.3X10-
3.3X10-
2.7X10-
1.6X10-
3.3X10-
1.1X10-
<5X10-
<3X10-
-------
GUIDELINES AND REPORTS 1401
Since the only alpha emitters measured in the lagoon-3 com-
posites were radionuclides of uranium and plutonium, it is not
possible to present data on the relative contributions of individual
radionuclides to the total alpha activity of these composites.
From the data on the uranium and plutonium, it may be observed
that 18 times more uranium alpha activity than plutonium alpha
activity was discharged from lagoon-3 during the period May-
October 1969. Uranium-232 accounted for about 70 percent of this
uranium activity. This relationship is just the reverse of what
was the case for the interceptor composites. Twenty times more
plutonium alpha activity than uranium alpha activity was dis-
charged from the plant to the interceptor tanks during the period
covered by the interceptor composites. This would indicate that
the radionuclides of plutonium become insoluble to a greater ex-
tent than those of uranium in passing through the lagoon system.
Activity Deposited in Lagoon System
An estimate of the amount of activity deposited in the lagoon
system can be made from a comparison of the activity discharged
from the plant to the interceptor tanks and the activity discharged
from lagoon-3 to the aqueous environment for a given period of
time. The lagoon system hold-up period is estimated to be about
1 month. Therefore, all the waste represented by the interceptor
composites for the periods of 4/1-5/21/69 and 5/21-8/4/69 would
have passed through the lagoon system during the period of 5/1-
9/4/69. A comparison of the amounts of activity of the various
radionuclides discharged from the plant with the amounts dis-
charged from lagoon-3 to the aqueous environment during this
period is presented in table 17.
From the data in table 17, it can be estimated that the following
relative amounts of activity leaving the plant were retained in the
lagoon system through sedimentation:
(a) 50 percent of the gross beta and 67 percent of the gross alpha.
(b) Greater than 90 percent of the cerium-144, promethium-147, zirconium-
95 and plutonium radionuclides.
(c) 70-75 percent of the cesium radionuclides, 59 percent of the cobalt-60,
39 percent of the ruthenium-106, 13 percent of the antimony-125, and only 7
percent of the strontium-90.
[p. 22]
(d) 8.5 times more uranium-232 and 3.8 times more uranium-234 were dis-
charged from lagoon-3 than were discharged from the plant during this period.
It would appear that uranium previously deposited in the lagoon sediments
from a previous campaign was being redissolved and discharged from lagoon-3
during this period.
-------
1402 LEGAL COMPILATION—RADIATION
Distribution of Radionuclides Betioeen Dissolved and Suspended
Solids
The behavior of the various radionuclides in the aqueous en-
vironment will be dependent, to a great extent, upon whether the
radionuclide remains soluable or becomes associated with the sus-
pended material (insoluble) in the water. Information on the
solubility of the radionuclides leaving lagoon-3 is useful in evalu-
ating their behavior in the stream environment. Radionuclides
associated with the suspended solids when leaving lagoon-3 can
be expected to settle out in the stream shortly after discharge.
Their transport in the aqueous environment would then be con-
trolled by the movement of the bottom sediments rather than by
the water itself. Table 18 shows the relative amounts of the
various radionuclides associated with the dissolved and suspended
solids in the water leaving lagoon-3 for the period May-October
1969. Most of the ruthenium-106, strontium-90, antimony-125,
cobalt-60, and uranium discharged from lagoon-3 are present in a
soluble form. The cesium radionuclides are partially present in
both a soluble and insoluble form. Almost all of the cerium-144,
promethium-147, zirconium-95, manganese-54, and plutonium are
present in an insoluble form. A study of the relationship between
these discharged activities and the concentrations present in the
aqueous environment is reported in the following section.
[p. 23]
-------
GUIDELINES AND REPORTS 1403
TABLE 17. COMPARISON OF ACTIVITIES DISCHARGED FROM PLANT WITH THOSE DISCHARGED TO AQUEOUS
ENVIRONMENT
Radionuclide
Gross a
Gross /;
i«Ru
'"Cs
'"Cs
"Sr
'«Ce
'"Pm
«Zr
"Co
«»Sb
«Mn
"«Pu
j»pu
I4jpu
J»U
JMU
2»U
Interceptor
1.2X10-'
1.2 X 102
7.1X10'
1.1X10'
3.8
5.6
8.5
4.9
9.4X10-'
2.9X10-'
3.8X10-'
5.6X10-3
2.5X10-2
6.2X10-'
2.7
2.0X10-'
1.8X10-'
8.3X10-'
Curies discharged
' Lagoon-:
3.9X10-
6.0X10'
4.3X10'
3.3
9.6X10-
5.2
1.4X10-
7.8X10-
3.9X10-
1.2X10-
3.3X10-
8.0X10-
5.3X10-
1.0X10-
6.5X10-
1.7X10-
69X10-
7.6X10-
Lagoon-3
2 Interceptor
> 0.33
0.50
0.61
0.30
0.25
0.93
0.02
0.02
<0.01
0.41
0.87
0.14
0.02
0.02
0.02
8.5
3.8
0.92
' Activities discharged from plant to interceptor tanks from 4/1 to 8/4 1969 with decay correction for
30-day hold-up period.
2 Activities discharged from lagoon-3 to aqueous environment from 5/1 to 9/4 1969.
[p. 24]
TABLE 18. DISTRIBUTION OF RADIONUCLIDES BETWEEN DISSOLVED AND SUSPENDED SOLIDS IN WATER
DISCHARGED FROM LAGOON-3 MAY-OCTOBER 1969
Radionuclide
Gross a
Gross ^
1MRU
'»Cs
'»Cs
»Sr
i«Ce
»'Pm
"Zr
"Co
iiiSb
«Mn
Pu (a)
U (a)
Total curies
discharged
4.8X10-'
8.2X10'
5.2X10'
8.0
2.0
8.3
1.6X10-'
9.2X10-'
4.6X10-'
2.0X10-'
5.9X10-'
2.7X10-'
1.8X10-'
3.2X10-'
Percent of total
Dissolved
79
89
91
70
69
88
0
0
0
95
98
0
6
92
activity discharged
Suspended
21
11
9
30
31
12
100
100
100
5
2
100
94
8
[P- 25]
RELATIONSHIP OP STREAM CONCENTRATIONS TO LAGOON-S
DISCHARGES
Samples Collected
To define the relationship between the concentrations of radio-
-------
1404 LEGAL COMPILATION—RADIATION
nuclides discharged from lagoon-3 and the concentrations present
in the Buttermilk and Cattaraugus Creeks, water samples were
collected at the point of discharge (lagoon-3) and various locations
along the creeks on June 17 and 18 and November 4 and 5, 1969.
The locations from which samples were collected on these days are
listed below:
Date Sampling Location
June 17 2, 3, 4, 5, 6, 7, 8
June 18 2, 4, 5, 6, 7, 8
June 19 0, 00
November 4 2, 5, 7
November 5 2, 5 (samples were collected at
station 5 every 2 hrs from
0830-1430)
These samples were immediately separated in the field into
dissolved and suspended solids fractions by filtration through an
0.45 /x membrane filter, and the dissolved solids fractions acidified
to 1 percent nitric acid.
Measurements and Results
Both the dissolved and suspended solids fractions of these sam-
ples were analyzed for gross alpha, gross beta, ruthenium-106,
cesium-134, cesium-137, strontium-90, cerium-144, zirconium-95,
cobalt-60, antimony-125, and manganese-54. Tritium was meas-
ured in the dissolved solids fractions only. The analytical proced-
ures used in the analysis of these samples are described in Ap-
pendix III. Table 19 presents the results of these measurements
for the June 1969 samples and table 20 for the November 1969
samples. Cerium-144, zirconium-95, and manganese-54 were not
detected in either the dissolved or suspended solids fractions of
these samples. Antimony-125, cobalt-60, and gross alpha were
not detected in the suspended solids fractions of these samples.
The minimum detectable concentrations in /iCi/ml for these ra-
dionuclides in the samples from the Buttermilk Creek for the
volumes analyzed and the counting times used were as follows:
cerium-144 = 3 X 10~T; zirconium-95 = 5 X 10~s; manganese-54 =
3 X 10 s; antimony-125 = 4 X HH; cobalt-60 = 3 X 10-to; gross
alpha = 1 X 10-°.
Plutonium and uranium analyses were carried out on the sam-
ples collected from locations 2 and 5 only. The results of these
analyses are presented in table 21.
[p. 26]
-------
GUIDELINES AND REPORTS
1405
=3
O
z 2
~"
8-2
o o o o o Q o
X X X X X X X
in CM co" co co CM
o o o o o o o
X X X X X X X
CM CO CO CM >-i ^
1 1 I 1 1 1
O O 0 O O 0 O
X X X X X X X
I-N. ^H CM rH o r- CM
i I 1 1 . ! 1
O O O O O O O
X X X X X X X
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1406
LEGAL COMPILATION—RADIATION
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-------
9526—EPA
GUIDELINES AND REPORTS
1407
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[p. 29]
-------
1408 LEGAL COMPILATION—RADIATION
Stream and Discharge Variables
June -1969
Prior to the sampling, waste had been discharged from lagoon-3
continuously since June 10. The discharge rate had been adjusted
periodically according to the flow in Cattaraugus Creek. On June
17 the discharge rate from lagoon-3 was 95 gal/min and on June
18 it was 75 gal/min. The pH of the discharge was 11.5.
The flow-rate of the Buttermilk Creek was calculated to be
1.2 X 104 gal/min on June 17 and 8.5 X 103 gal/min on June 18.
The flow-rate of the Cattaraugus Creek was calculated to be 1.2 X
105 gal/min on both 6/17 and 6/18.5 Nuclear Fuel Services (5)
reported the Cattaraugus Creek flow-rate to be 1.3 and 1.1 X 105
gal/min on these days.
The suspended solids concentration in the water leaving lagoon-
3 was 7 mg/1 on 6/17 and 6 mg/1 on 6/18. The concentration in
the Buttermilk Creek on these days ranged from 8-10 mg/1. The
suspended solids concentration in Cattaraugus Creek on these days
was not measured.
November -1969
Prior to the sampling on November 4, waste had been dis-
charged from lagoon-3 continuously since October 31 at a rate of
60 gal/min and a pH of 9.5. The discharge was terminated at
11:00 a.m. on November 4 and resumed at 9:00 a.m. November 5
at a flow-rate of 75 gal/min and a pH of 7. The samples collected
on November 4 are representative of stream conditions during
continuous discharge (prior to shutdown). The samples collected
on November 5 are representative of stream conditions during a
non-discharge period and during the initial stages following the
resumption of discharge prior to establishment of equilibrium
between the discharge and the streams.
The flow-rate of the Buttermilk Creek was calculated to be
5.2 X 10' gal/min on 11/4 and 4.0 X 104 gal/min on 11/5. The
flow-rate in the Cattaraugus Creek was calculated to be 2.1 X 105
gal/min on 11/4. The suspended solids concentrations in mg/1 on
these days were as follows:
NOVEMBER 4 NOVEMBER 5
Lagoon-3 78 11
Buttermilk Creek 160 70
Cattaraugus Creek 190 42
5 The flow-rates were calculated from the tritium concentrations as follows:
:!H cone in lagoon-3
Flow-rate gal/min = X gal/min leaving lagoon-3
^H cone in creek
[p. 30]
-------
GUIDELINES AND REPORTS 1409
Data Evaluation
Tritium, ruthenium-106, and strontium-90 were the principal
radionuclides present in the Buttermilk and Cattaraugus Creeks
during both the sampling periods. Other radionuclides measured
in the creeks, but in lower concentrations, were cesium-137, ce-
sium-134, antimony-125, cobalt-60, uranium-232, uranium-234 and
uranium-238. Almost all of the activity of those radionuclides
detected in the creeks were associated with the dissolved solids
with the exception of the radionuclides of cesium. For the cesium
radionuclides, 40-95 percent of their activity was associated with
the suspended solids. The cesium radionuclide concentration in a
water sample increased with the suspended solids concentration
and the percentage associated with the suspended solids fractions
also increased. Listed in table 22 are the relative contributions of
the various radionuclides to the beta activity (exclusive of 3H) in
Buttermilk and Cattaraugus Creeks for the June and November
1969 sampling periods.
TABLE 22. RADIONUCLIDES CONTRIBUTING TO BETA ACTIVITY OF BUTTERMILK AND CATTARAUGUS CREEKS
Radionuclide Percent of beta activity1
Buttermilk Creek-Site 5 Cattaraugus Creek-Site 7
6/17/69 11/4/69 6/17/69 11/4/69
l°'Ru
"Sr
u'Cs
is«Cs
TMSb
«>Co
88
10
0.8
03
... 0.8
40
24
26
6
4
91
8
0.4
0.1
0 6
<0 1
39
28
25
8
1 Relative contribution of the individual radionuclide to the sum total of the activities of the radionu-
clides listed.
[p. 31]
The strontium-90, cesium-134, and cesium-137 contributions to
the beta activity in November 1969 were greater than in June
1969. These differences in relative distribution of beta activity
were due to a number of factors, such as: a) the waste discharged
during the two periods had different distributions of beta activity,
b) the November creek samples had high suspended solids con-
centrations resulting in higher cesium-134 and -137 concentrations,
c) the pH of the November discharge was considerably lower than
that of June resulting in lower absorption of strontium-90 by the
stream system (see section below).
-------
1410 LEGAL COMPILATION—RADIATION
Absorption of Radionuclides by Stream
The ratio of the concentration of a radionuclide in the dissolved
solids fractions of water leaving lagoon-3 to the concentration in
the dissolved solids fractions of water at a location on a stream can
be used to describe the behavior of that radionuclide in the stream
environment and this ratio will be denned as the Effective Dilution
Factor. The Effective Dilution Factor can be further denned as
follows:
EDF = (DF) (AF)
EDF = Effective Dilution Factor
DF = Water Dilution Factor
AF = Stream Absorption Factor
The ratio of the tritium concentration in the water leaving la-
goon-3 to the concentration in the water at a location is a measure
of the Water Dilution Factor (DF). All other processes which
remove a radionuclide from the water are included in the Stream
Absorption Factor (AF).
Table 23 presents the Effective Dilution Factors and table 24
presents the Stream Absorption Factors for the radionuclides
present in Buttermilk and Cattaraugus Creeks during June 17, 18
and November 4, 1969.
As stated above the Effective Dilution Factor for tritium is equal
to the Water Dilution Factor for the streams. The Water Dilution
Factor is a function of the flow-rates of the water leaving lagoon-3
and the water in Buttermilk and Cattaraugus Creeks and will vary
according to these flows.
[P. 32]
-------
GUIDELINES AND REPORTS
1411
§
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[p. 33]
-------
1412 LEGAL COMPILATION—RADIATION
TABLE 24. STREAM ABSORPTION FACTORS FOR RADIONUCLIDES IN BUTTERMILK AND CATTARAUGUS CREEKS
JUNE 17, 18, AND NOVEMBER 4, 1969
Location
3
5
7
5
7
5
7
Date
6/17
6/17
6/17
6/18
6/18
11/4
11/4
Stream absorption factors-AF
">'Ru
1.3
1.5
1.2
1.5
1.5
1.0
1.4
"'Cs
2.5X10'
1 0X102
1.0X102
1.4X10'
1.3X10'
1.2X10'
—
•°Sr
3.5
3.6
3.4
4.3
4.1
1.1
1.1
'«Sb
1.4
1.4
1.5
1.7
1.4
0.8
—
"Co
2.2
2.6
2.2
2.5
3.1
—
—
The Stream Absorption Factors for June 17 indicate that most
of the removal of activity by absorption takes place during pas-
sage of the water between sites 2 and 3. This may be due to the
pH of the water which was 11.5 upon discharge from lagoon-3.
The absorption of the radionuclides takes place while the waste is
still basic, prior to dilution by the streams. The Stream Absorp-
tion Factor for strontium-90 on November 4 was 1.1, a factor of
about 3 less than on June 17. The pH of the waste discharge had
been reduced to 7 and this appears to have resulted in a lower
removal of strontium-90 by the stream system. The amounts of
activity removed from the water in its passage between lagoon-3
and the Cattaraugus Creek may be estimated from the Stream
Absorption Factors for site 7. These values for the 2 sampling
periods are presented below in table 25.
TABLE 25. RELATIVE AMOUNTS OF ACTIVITY REMOVED FROM WATER IN PASSAGE FROM LAGOON-3 TO
CATTARAUGUS CREEK
Radionuclide Percent of activity removed in stream
"»RU
IJ'Cs
»Sr
»Co
June 17, 18, 1969
. . . . 26
>99
72
31
66
November 4, 1969
29
>99
9
[p. 34]
COMPARISON OF THE CONCENTRATIONS OF RADIONUCLIDES
IN CATTARAUGUS CREEK WITH THE 10CFR20 DISCHARGE
CONCENTRATION LIMITS
A comparison of the concentrations of the radionuclides in
Cattaraugus Creek with the 10CFR20 discharge concentration
-------
GUIDELINES AND REPORTS
1413
limits (6) was made to provide information of the relative dosi-
metric importance of these radionuclides. Presented below in
table 26 are the fractions of the 10CFR20 discharge concentration
limits for each of the radionuclides measured in Cattaraugus Creek
on June 17 and November 4, 1969.
TABLE 25. FRACTIONS OF 10CFR20 DISCHARGE CONCENTRATION LIMITS IN CATTARAUGUS CREEK' FOR
INDIVIDUAL RADIONUCLIDES
Radionuclide
Fraction of concentration limit
»Sr
1MRu . . . . . . .
>H
"7Cs
"sSb
«Co
June 17, 1969 November 4, 1969
1.7X10
5 2X10-
. . 1 1X10-
80X10'
4.0X10
1X10'
2.3X10-'
7.5X10-1
1.0X10-'
1.5X10-3
<4X10-4
<2X10-"
1 Sample collected at site 7 (Felton Bridge)
These data show that strontium-90 at about 20 percent of the
concentration limit is the radionuclide of most dosimetric signifi-
cance in the Cattaraugus Creek. Ruthenium-106 and tritium con-
centrations also exceeded 1 percent of the concentration limits on
June 17.
The cesium-137 concentration in Cattaraugus Creek is only a
very small fraction of the concentration limit. However, the data
on cesium-137 in fish (7) indicate concentrations which are dosi-
metrically significant when the fish is ingested. This shows that a
comparison of concentration of a radionuclide with the concentra-
tion limit is only one of the factors which must be considered in
evaluating the dosimetric significance of that radionuclide since
the concentration limit does not take into consideration concentra-
tion which may occur in the pathways to man; such as, fish, deer,
or other wildlife which are influenced by the stream system.
[p. 35]
Shleien (8) has calculated the dose commitments accrued in
1968 for ""Sr, 13TCs, 13tCs, ")(1Ru, and 3H ingested in fish from the
Cattaraugus Creek for typical and maximum individuals.
RADIONUCLIDES IN BOTTOM SEDIMENTS FROM BUTTERMILK
AND CATTARAUGUS CREEKS
Samples Collected
Bottom sediments were collected from sites 5 and 8 on May 28,
1968, June 19 and November 6, 1969. The samples were collected
-------
1414 LEGAL COMPILATION—RADIATION
using a scoop near the edge of the stream where sediments were
likely to collect. The sample was then passed through a coarse
screen to remove leaves, sticks, etc.
Measurements and Results
The sediment samples were analyzed for ruthenium-106, cesium-
134, cesium-137, strontium-90, cobalt-60, plutonium-238, and plu-
tonium-239. Table 27 presents the results of these measurements
in microcuries per gram of dried sediment. The analytical tech-
niques used are described in Appendix III.
Data Evaluation
The concentrations of radionuclides in the sediments from site 8
increased with each collection. This increase in concentration may
have been due to: a) an increase in the plant discharge, b) a
stream variable influencing the bottom sediments, and c) a vari-
able in the sample collection.
The evaluation of sediment sample data is very difficult due to
the variable nature of the stream bottom from one collection period
to another and to the variability in sample collection from one
period to another (9). It was not within the scope of this phase
of the study to investigate these variables. A much more detailed
study of bottom sediments will be required in order to define the
usefulness of sediment sampling in environmental surveillance
programs.
[p. 36]
-------
GUIDELINES AND REPORTS
1415
m
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-------
1416 LEGAL COMPILATION—RADIATION
SUMMARY
The liquid waste affluents from Nuclear Fuel Services were
studied during a 6-month period from May through October 1969.
Composite samples of the liquid discharge were collected at the
interceptor tanks, the point of discharge from the plant, during
each of 3 fuel processing campaigns. At the same time, monthly
composites were collected from lagoon-3, the point of discharge to
the aqueous environment. These samples were analyzed for their
specific radionuclide content and from the volume of water repre-
sented by the composite, the total activity of each radionuclide for
a given discharge period was calculated.
The same radionuclides were discharged from the plant during
each of the three campaign periods studied. No relationship could
be established between the amount and burnup of fuel processed
and the amount of activity discharged from the plant to the lagoon
system during these periods. For the Yankee fuel campaign of
May-August 1969, the waste management practice and not the
amount of fuel processed was the controlling factor in the amount
of activity discharged from the plant to the lagoon system.
It was estimated that greater than 90 percent of the cerium-144,
promethium-147, zirconium-95, plutonium-238, plutonium-239, and
plutonium-241, and 75 percent of the cesium-134 and cesium-137
discharged from the plant were deposited by sedimentation in the
lagoon system, and therefore, not discharged to the aqueous en-
vironment. About 70 percent of the ruthenium-106 and 90 per-
cent of the strontium-90 and antimony-125, discharged from the
plant passed through the lagoon system and were discharged to
the stream system.
The amounts of specific radionuclides discharged from the la-
goon system to the aqueous environment during the period May-
October 1969 were as follows:
Radionuclide
>H
"»Ru
'»Cs
»«Cs
»Sr
i«Ce
"'Pm
Curies discharged
1.7X101
5.2X10'
8.0
2.0
8.3
1.6X10-'
9.2X10-2
Radionuclide
«Zr
«Co
'«Sb
«Mn
Pu(«)
U(«)
Gross a
Gross ji
Curies discharged
4.6X10-'
2.0X10-
5.9X10-
2.7X10-
1.8X10-
3.2X10-
4.8X10-
8.2X10'
[p. 38]
During June and November 1969 simultaneous sampling was
-------
GUIDELINES AND REPORTS 1417
carried out at lagoon-3, the point of discharge, and several loca-
tions on the stream system influenced by the discharge. Tritium,
ruthenium-106, and strontium-90 -vere the radionuclides present
in the highest concentrations in the Buttermilk and Cattaraugus
Creeks during these periods. Dilution factors were calculated at
various locations for each of the radionuclides measured in the
stream samples. From these data, an estimate was made of the
relative amount of a radionuclide removed from the water in pas-
sage from lagoon-3 to the Cattaraugus Creek. These data for
strontium-90 showed that 75 percent of the strontium-90 dis-
charged was removed from the water during June when the plant
discharge was pH = 11 and only 10 percent of the strontium-90
discharged was removed from the water during November when
the plant discharge was pH = 7.
A comparison of the concentrations of radionuclides in the Cat-
taraugus Creek (the unrestricted aqueous environment) with the
10CFR20 discharge concentration limits showed that strontium-90
was about 20 percent of the concentration limit during both sam-
pling periods. Ruthenium-106 was 5 percent of the concentration
limit during June and about 1 percent in November. Tritium was
1 percent of the concentration limit in June, and 0.1 percent in
November. All other radionuclide concentrations were less than
1 percent of the concentration limits during both the sampling
periods.
CONCLUSIONS AND RECOMMENDATIONS
The results of this report pertain primarily to the design of
surveillance programs around nuclear fuel reprocessing plants and
the designation of significant radionuclides and environmental
pathways. In order to maintain an evaluation of the radionuclides
released to the aquatic environment and to continually estimate
the population exposure from this pathway, a program of periodic
checks would have to be made relative to the following factors:
1. The waste discharged should be monitored for significant individual radio-
nuclides. Specific analyses should be carried out for tritium, ruthenium-106,
strontium-90, cesium-134, and cesium-137 in composite samples from lagoon-3:
The frequency of analysis should be determined by the concentrations of the
radionuclides released but at a minimum should be carried out monthly.
2. Specific analysis should be performed for tritium, ruthenium-106, stron-
tium-90, cesium-134, and cesium-137 in composite samples of water from Cat-
[p. 39]
taraugus Creek. Frequency of analysis should be determined by the concen-
trations of radionuclides present but at a minimum should be carried out
monthly.
-------
1418 LEGAL COMPILATION—RADIATION
3. Determination should be made of the concentrations of tritium, ruthenium-
106, strontium-90, cesium-134, and cesium-137 in the edible portions of fish,
deer, and other wildlife which would be influenced by the radionuclides present
in the stream environment.
4. Radiation dose estimates should be made by establishing the size of the
human population at risk for ingestion of fish and wildlife and the intakes of
the significant radionuclides via these pathways.
Work in these areas is currently being pursued by the facility,
the New York Department of Environmental Conservation, and
the U.S. Public Health Service. Activities of this nature would be
applicable for similar facilities in similar environments.
[p. 40]
REFERENCES
(1) KELLEHER, W. J. Environmental surveillance around a nuclear fuel
reprocessing installation 1965-1967. Radiological Health Data and Reports
10:329 (1969).
(2) PELLETIER, C. A. and C. W. SILL. Environmental measurements
around the Nuclear Fuel Services, Inc., fuel reprocessing plant, West
Valley, New York. Health Services Laboratory, Idaho Operations Office,
U.S. Atomic Energy Commission (April 1969).
(3) JOINT COMMITTEE ON ATOMIC ENERGY, Congress of the United
States. Part II. Hearing on the environmental effects of producing elec-
tric power. Statement by T. C. Runion, President of Nuclear Fuel Serv-
ices, Inc., U.S. Government Printing Office, Washington, D.C. (1970).
(4) U.S. ATOMIC ENERGY COMMISSION DOCKET 50201. Spent fuel
reprocessing plant (preliminary safety report). Part B of the license
application, Nuclear Fuel Services, Inc., West Valley, New York, July 26,
1962.
(5) KEELY, R. B., Health and Safety Officer, Nuclear Fuel Services, Inc.,
West Valley, New York. Personal communication.
(6) U.S. ATOMIC ENERGY COMMISSION, Division of Radiation Protec-
tion Standards Report. Appendix B Table II. Conditions and limitations
on the general license provisions of 10CFR150.20. Rules and Regulations.
(7) NEW YORK STATE DEPARTMENT OF HEALTH. Environmental
Radioactivity in New York State—1968 (July 1969).
(8) SHLEIEN, B. An estimate of radiation doses received by individuals
living in the vicinity of a nuclear fuel reprocessing plant in 1968. BRH/
NERHL70-1 (May 1970).
(9) JOHNSON, R. L. U.S. Department of Health, Education, and Welfare,
U.S. Public Health Service, Northeastern Radiological Health Laboratory,
Winchester, Mass. Personal communication.
[p. 41]
-------
GUIDELINES AND REPORTS 1419
4.3 URANIUM MINERS EXPOSURE GUIDELINES
4.3a RADIATION PROTECTION GUIDELINES,
FEDERAL RADIATION COUNCIL
January 15,1969,34 Fed. Reg. 576 (1969)
MEMORANDUM FOR THE PRESIDENT
DECEMBER 27, 1968.
Pursuant to Executive Order 10831 and Public Law 86-373, the Federal
Radiation Council transmits to you additional information and recommenda-
tions for the guidance of Federal agencies in their conduct of radiation
protection activities as they apply to the underground mining of uranium ore.
As noted in its July 21, 1967, memorandum for the President, the Council
stated that in approximately 1 year it would review its guidance for radiation
protection in uranium mining, and if indicated the recommendations would
be changed accordingly. The three recommendations were:
1. Occupational exposure to radon daughters in underground uranium mines be controlled so
that no individual miner will receive an exposure of more than 6 WLM in any consecutive
3-month period and no more than 12 WLM in any consecutive 12-month period. Actual ex-
posures should be kept as far below these values as practicable.
2. Areas in underground uranium mines, whether normally or occasionally occupied, be
monitored for the concentration of radon daughters in mine air. The location and frequency
of taking samples should be determined in relation to compliance with recommendation number 1.
3. Appropriate records of the exposure from radon daughters in the mine air received by
individuals working in uranium mines be established and maintained.
As used in this memorandum, the "Working Level" (WL) is defined as any
combination of the short-lived radon daughters in one liter of air that will
result in the ultimate emission of 1.3 x 105 MeV of potential alpha energy.
Exposure to these radon daughters over a period of time may be expressed
in terms of Working Level Months (WLM). Inhalation of air containing a
radon daughter concentration of 1 WL for 170 hours results in an exposure
of 1 WLM.
For its review the Council had the following information, which was de-
veloped over the past 18 months.
(a) Three reports from a special task group established to review progress made in radiation
protection practices in uranium mines. The task group consisted of representatives of Federal
and State agencies, industry, labor, medical, and standard-setting organizations.
(b) A report by the Resource Management Corporation on a short-term study of the impact
of uranium mining safety standards on the uranium producing and nuclear power industries.
(c) A report by the advisory committee to the FRC from the Division of Medical Sciences of
the National Academy of Sciences-National Research Council (NAS-NRC). This report,
"Radiation Exposure of Uranium Miners," included a review of the testimony presented in the
1967 hearings of the Joint Committee on Atomic Energy, as well as the updated epidemiology
study conducted by the U.S. Public Health Service.
(d) U.S. Department of Labor hearings on Radiation Standards for Mining under the Walsh-
Healey Public Contracts Act, November 20 and 21, 1968.
On the basis of its review of the information, the Council has reached the
following conclusions:
1. That available data are still insufficient, though somewhat more complete than they were
when the Council made its recommendations to the President on July 21, 1967, to determine an
exposure level at or below which underground uranium miners may be exposed without signifi-
cantly increased risk of lung cancer.
2. That available data indicate a higher than expected mortality rate in the lower exposure
categories (i.e., less than 840 WLM) as well as in the higher categories (i.e., larger than 840
WLM).
The Council therefore recommends that:
1. Occupational exposure to radon daughters in underground uranium mines be controlled
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1420 LEGAL COMPILATION—RADIATION
so that no individual miner will receive an exposure of more than 6 WLM in any consecutive
3-month period and no more than 12 WLM in any consecutive 12-month period. Actual ex-
posures should be kept as far below these values as practicable.
2. Areas in underground uranium mines, whether normally or occasionally occupied, be
monitored for the concentration of radon daughters in mine air. The location and frequency of
taking samples should be determined in relation to compliance with recommendation number I.
3. Appropriate records of the exposure from radon daughters in the mine air received by in-
dividuals working in uranium mines be established and maintained.
4. As a policy measure of prudence the agencies having responsibility for regulating the
uranium mining industry be advised that the Federal Radiation Council recommends an annual
exposure level of 4 WLM as of January 1, 1971.
5. Prior to this date, the Council will consider all pertinent information including epide-
miological data, miner exposure records, health considerations, mining practices and costs thereof,
and applicable research and development results, to determine whether or not to modify this
recommendation.
6. The uranium mining industry is urged to continue efforts to progressively lower exposure
levels in the mines so that the anticipated 4 WLM standard can be attained by January 1, 1971.
7. To assist the Council in its periodic review of radiation protection in uranium mines an
interagency group will be established with representation from agencies of the Council. This
group will keep all relevant information and developments under continuing surveillance and
make reports to the Council in advance of its periodic review.
8. Agencies having responsibility for the protection of underground uranium miners should
establish levels of radon daughter concentrations in underground uranium mines above which
(a) occupancy would be restricted or prohibited, and (b) action would be required to reduce
concentrations. Such limits on concentrations are intended to assist in ensuring that exposures
of individual miners are held within the approved guidance. In general, adequate control of the
environment is recommended over achieving compliance with the exposure guide by distributing
exposures over a larger number of miners.
Cigarette smoking in uranium mines. As noted in the task group reports
and the report of the NAS-NRC advisory committee to the FRC, existing data
strongly suggest that cigarette smokers among the underground uranium
miners are particularly susceptible to lung cancer. This may be a synergis-
tic effect between the inhalation of cigarette smoke and radon daughter
products or other materials associated with uranium mining. Therefore, the
Council urges that concerted effort be made by all concerned to discourage
cigarette smoking by underground uranium miners.
If the foregoing recommendations are approved by you for the guidance
of Federal agencies in the conduct of their radiation protection activities, it
is further recommended that this memorandum be published in the FEDERAL
REGISTER.
WILBUR J. COHEN,
Chairman.
The recommendations in the preceding memorandum are approved for the
guidance of Federal agencies, and the memorandum shall be published in the
FEDERAL REGISTER.
LYNDON B. JOHNSON.
4.3b RADIATION PROTECTION GUIDELINES,
FEDERAL RADIATION COUNCIL
December 18,1970, 35 Fed. Reg. 19218 (1970)
MEMORANDUM FOR THE PRESIDENT
DECEMBER 1,1970.
In accordance with Executive Order 10831 and Public Law 86-
373, the Federal Radiation Council transmits to you a recora-
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GUIDELINES AND REPORTS 1421
mendation for the modification of guidance applicable to Federal
agencies in their conduct of radiation protection activities as it
applies to underground mining of uranium ore.
The latest recommendations of the Federal Radiation Council
on this subject were submitted to the President in a memorandum,
December 27, 1968. The recommendations were approved by the
President on January 11, 1969, and the memorandum was pub-
lished in the FEDERAL REGISTER, January 15, 1969 (34F.R. 576).
The memorandum contained four recommendations bearing di-
rectly on the modification recommended now. These were:
1. Occupational exposure to radon daughters in underground uranium mines
be controlled so that no individual miner will receive an exposure of more than
6 WLM in any consecutive 3-month period and no more than 12 WLM in any
consecutive 12-month period. Actual exposures should be kept as far below
these values as practicable.
4. As a policy measure of prudence the agencies having responsibility for
regulating the uranium mining industry be advised that the Federal Radiation
Council recommends an annual exposure level of 4 WLM as of January 1, 1971.
5. Prior to this date, the Council will consider all pertinent information
including epidemiological data, miner exposure records, health considerations,
mining practices and costs thereof, and applicable research and development
results, to determine whether or not to modify this recommendation.
7. To assist the Council in its periodic review of radiation protection in
uranium mines an interagency group will be established \vith representation
from agencies of the Council. This group will keep all relevant information
and developments under continuing surveillance and make reports to the
Council in advance of its periodic review.
Pursuant to recommendation 7, the Interagency Uranium Min-
ing Radiation Review Group was established under the chairman-
ship of the Surgeon General, U.S. Public Health Service. At its
last meeting the Interagency Group concluded that the information
that would permit the Council to fulfill adequately the requirement
of recommendation 5 would not be available in time to permit the
Council to reconsider the guidance before the date in recommenda-
tion 4. Accordingly, the Group recommended to the Council that
the date in recommendation 4 be changed to July 1, 1971.
The Federal Radiation Council concurs in the judgment of the
Interagency Group that more time is needed to take the action
provided for in recommendation 5, and agrees that a postponement
for the period of time required to complete the review is desirable.
The Council, therefore, recommends that the date in recommen-
dation 4 of the Council's memorandum of December 27, 1968, to
the President, be changed to July 1, 1971.
If the foregoing recommendation is approved by you for the
guidance of Federal agencies in the conduct of their radiation pro-
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1422 LEGAL COMPILATION—RADIATION
tection activities, it is further recommended that this memorandum
be published in the FEDERAL REGISTER.
ELLIOT L. RICHARDSON,
Chairman.
The recommendation in the preceding memorandum is approved
for the guidance of Federal agencies and the memorandum shall be
published in the FEDERAL REGISTER.
RICHARD NIXON.
4.3c RADIATION PROTECTION GUIDANCE,
UNDERGROUND MINING OF URANIUM ORE,
ENVIRONMENTAL PROTECTION AGENCY
May 25,1971,36 Fed. Reg. 9480 (1971)
UNDERGROUND MINING OF URANIUM ORE
RADIATION PROTECTION GUIDANCE FOR FEDERAL AGENCIES
The President's Reorganization Plan No. 3 of 1970 transferred
to the Environmental Protection Agency (EPA) the functions of
the former Federal Radiation Council (FRC) which was estab-
lished under Executive Order 10831 and Public Law 86-373.
These functions include recommending radiation protection guid-
ance for Federal agencies.
In a memorandum to the President published in the FEDERAL
REGISTER on December 18, 1970, the FRC recommended that an-
nual exposure levels of miners to radon daughters in underground
uranium mines should be no more than 4 WLM,1 effective as of July
1, 1971. This memorandum also recommended that the FRC con-
sider additional information to determine whether or not to modify
this recommendation. The additional information has been con-
sidered and the Administrator of EPA has concluded that this
recommendation should not be modified.
Public comment on this matter is invited.
BACKGROUND
The FRC, noting an increase in the 1960s in lung cancer among
underground uranium miners in the United States associated with
1 "WLM" is Working Level Months, a term commonly used to express a miner's calculated
exposure to radon daughter products found in the mine air. This is derived from the Working
Level (WL), a unit which is denned as any combination of short-lived radon daughters in one
liter of air that will result in the ultimate emission of 1.3 x 10" MeV of potential alpha energy.
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GUIDELINES AND REPORTS 1423
the inhalation of radioactive materials, undertook a study of the
problem, resulting in issuance of Report No. 8, "Guidance for the
Control of Radiation Hazards in Uranium Mining," in September
1967.
The FRC submitted three memorandums to the President on this
subject, and the recommendations contained in the memorandums
were approved by the President. In the first memorandum, ap-
proved by the President and published in the FEDERAL REGISTER
on August 1, 1967, 32 F.R. 1183, the FRC initially considered ex-
posure guidance of 36, 12 and 4 WLM per year. It concluded that
the best balance between risks to the miners and control capability
was a limit of 12 WLM per year based on the information available
at that time on epidemiological studies, animal experiments, miner
exposure records, health considerations, mining practices and costs
thereof, and applicable research and development results.
The second memorandum, approved by the President and pub-
lished in the FEDERAL REGISTER on January 15, 1969, 34 F.R. 576,
includes, among others, the following five recommendations:
1. Occupational exposure to radon daughters in underground uranium mines
be controlled so that no individual miner will receive an exposure of more than
6 WLM in any consecutive 3-month period and no more than 12 WLM in any
consecutive 12-month period. Actual exposures should be kept as far below
these values as practicable.
4. As a policy measure of prudence the agencies having responsibility for
regulating the uranium mining industry be advised that the Federal Radiation
Council recommends an annual exposure level of 4 WLM as of January 1,1971.
5. Prior to this date, the Council will consider all pertinent information
including epidemiological data, miner exposure records, health considerations,
mining practices and costs thereof, and applicable research and development
results, to determine whether or not to modify this recommendation.
6. The uranium mining industry is urged to continue efforts to progressively
lower exposure levels in the mines so that the anticipated 4 WLM standard
can be attained by January 1, 1971.
7. To assist the Council in its periodic review of radiation protection in
uranium mines an interagency group will be established with representation
from agencies of the Council. This group will keep all relevant information
and developments under continuing surveillance and make reports to the
Council in advance of its periodic review.
Pursuant to recommendation No. 7, an interagency group was
established. This group was known as the Interagency Uranium
Mining Radiation Review Group (IUMRRG) and consisted of
representatives from the Department of Health, Education, and
Welfare, the Department of Agriculture, the Department of the
Interior, the Department of Labor, the Department of Commerce,
the Department of Defense, and the Atomic Energy Commission.
-------
1424 LEGAL COMPILATION—RADIATION
The Surgeon General, U.S. Public Health Service, was appointed
Chairman.
The third memorandum, approved by the President and pub-
lished on December 18, 1970, 35 F.R. 9218, stated that IUMRRG
required additional time to complete its review and recommended
that the effective date be postponed from January 1, 1971 to July
1, 1971.
CONCLUSIONS
Following a review and analysis of the information referenced
below, the Administrator has reached the following conclusions:
a. The major areas of consideration in connection with determining radia-
tion protection guidance for uraninum miners are:
(1) Protection of the health of uranium miners.
(2) Technical feasibility of achieving various levels of exposure.
(3) Economic impact of achieving various levels of exposure.
b. The primary objective of EPA guidance for underground uranium mining
standards is to protect miners from radiation induced lung cancer. Although
the magnitude of risk attributable to radiation exposures incident to uranium
mining is still in dispute among the participants in the IUMRRG review, it
is concluded that radiation exposure is the major identified factor causally
related to an increased lung cancer risk. Thus, the major principle on wThich
EPA guidance is based is the reduction of the radiation exposure to uranium
miners to the lowest practicable level.
c. A standard of 4 WLM per year is technically feasible.
d. A standard of 4 WLM per year would not have a severe impact on the
underground uranium mining community, provided additional time is allowed
for compliance in certain instances.
e. A standard greater than 4 WLM per year probably would result in
dosages exceeding those permitted for other occupational radiation exposure
situations.
f. The risk of lung cancer appears to be enhanced by cigarette smoking in
combination with the inhalation of radioactive materials; therefore, smoking
by underground uranium miners should continue to be discouraged.
DECISIONS
In light of the conclusions noted above, the Administrator does
not find a basis for modifying the guidance approved by the Pres-
ident that an annual exposure level of 4 WLM be effective as of
July 1, 1971.
The authority which EPA derived from the former FRC is
limited to recommending guidance for Federal agencies. Other
agencies are responsible for setting and enforcing standards. It is
for these agencies to consider what provision it is appropriate to
make, in enforcement of standards, for those cases where imme-
diate enforcement of a 4 WLM per year standard would cause
excessive financial loss which would compel the closing of mines
resulting in substantial loss of employment for miners. It is the
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GUIDELINES AND REPORTS 1425
Administrator's concern that, if variances are granted for specific
mines by the appropriate regulatory agencies, such mines be
brought into compliance with the 4 WLM per year guidance at the
earliest possible time.
In this connection it should be noted that the recommendation
of 4 WLM per year was approved by the President and published
in the FEDERAL REGISTER on January 15, 1969, to be effective
January 1, 1971. (The effective date was later extended to July 1,
1971.) Thus, industry has been aware of the impending 4 WLM
per year limit for 21/2 years.
The Administrator strongly urges that epidemiological and re-
lated experimental studies and research on better radiation control
procedures and methods continue to be actively and vigorously
pursued by both the industry and Federal agencies.
AVAILABILITY OF REPORTS TO PUBLIC
The foregoing conclusions and decisions were based on informa-
tion and reports prepared by the IUMRRG, subgroups of the
IUMRRG, and a report of the National Academy of Sciences-
National Research Council (NAS-NRC). These reports are avail-
able to the public at EPA Headquarters and the 10 EPA Regional
Offices at the addresses noted at the end of this notice.
For the convenience of the public, the following reports and
summaries are set forth below:
(1) The IUMRRG report by the Chairman of the IUMRRG.
(2) Summaries of the subgroup reports.
(3) The conclusions of the NAS-NRC report.
IUMRRG REPORT
The final report of the IUMRRG was in the form of a letter dated
April 26, 1971, from the Chairman of the IUMRRG, the Surgeon
General, U.S. Public Health Service. This letter is set forth below:
DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
WASHINGTON, D.C. 20201
SURGEON GENERAL OF THE PUBLIC HEALTH SERVICE
HON. WILLIAM D. RUCKELSHAUS,
A dminis trator,
Environmental Protection Agency,
Washington, D.C. 20460.
April 26, 1971.
DEAR MR. RUCKELSHAUS: In accordance with the recent exchange of cor-
respondence between you and Secretary Richardson concerning the efforts of
the Interagency Uranium Mining Radiation Review Group which I chair, I
am enclosing final reports summarizing the conclusions reached by the sub-
groups of our committee. I believe that these reports, as well as the full
-------
1426 LEGAL COMPILATION—RADIATION
reports of the subgroups sent to you earlier, represent a workmanlike review
of the assigned problems.
The methodology and content of the reports were discussed at length at a
meeting of the Interagency Review Group held on April 1, 1971. While there
were a number of differences of opinion on other matters, the Group did reach
a consensus that there is an increased risk of lung cancer associated with all
ranges of radiation exposure examined, including the 120-359 cumulative
working level month category. It seems clear to me then that the guidance
concerning the allowable radiation level in uranium mines must [sic] be as
low as possible.
The courses of action available to you concern principally the schedule for
achievement of the lower levels. The arguments for early adoption of low
levels center around human health considerations—lower levels established
soon will achieve lower total lifetime exposure to hazard. The arguments for
more time to achieve the lower guidance center around economic considera-
tions—possible damage to the domestic uranium mining industry may result
from more stringent requirements. Comments from each Review Group mem-
ber on both the appropriate level to be established and the schedule for reach-
ing that goal are attached for your use in reaching a decision.
A discussion of the alternatives I outlined in an enclosure to my February
26 memorandum to the members of the Review Group follows:
1. That the guidance of 4 WLM per year go into effect on or before July
1, 1971.
Pro: Exposure of miners to radiation in the uranium mines would be de-
creased; total exposure in cumulative working level months would increase
at a lower rate than at present.
Con: Total exposure of miners to radiation in the uranium mines would
sible adverse affect on the domestic uranium mining industry. Some miners
might be thrown out of work.
2. That the guidance of 8 WLM per year go into effect in 1 year and that
the guidance of 4 WLM per year go into effect in 2 years.
Pro: Industry would have time to comply with lower standards gradually thus
diminishing possible economic damage and layoffs; total exposure in cumu-
lative working level months would increase at a lower rate than at present.
Con: Total exposure of miners to radiation in the uranium mines would
increase at a higher rate than under a 4 WLM per year guidance.
3. That the guidance remain at 12 WLM.
Pro: Industry is, by and large, already complying with this exposure guid-
ance; no increased cost would be necessary; there would be no adverse eco-
nomic impact.
Con: Exposure of miners to radiation in the uranium mines would remain at
the current level as would their cumulative total exposure.
The member from the Atomic Energy Commission urges the continuation of
the Review Group. With the submission of this letter to you, however, I
believe that the work of the present Interagency Uranium Mining Radiation
Review Group is concluded, and I shall convene no further sessions. I would,
however, be happy to arrange for the participation of this Department in any
interagency committee constituted to consider this subject.
Sincerely yours,
JESSE L. STEINFELD, M.D.
Surgeon General, Chairman,
Interagency Uranium Mining Radiation Review Group.
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GUIDELINES AND REPORTS 1427
Enclosures:
NOTE: Enclosures are located at EPA Headquarters and the 10 EPA
Regional offices at the addresses noted at the end of this notice.
NAS-NRC REPORT
The NAS-NRC prepared a report for the IUMRRG dated Jan-
uary 27, 1971, titled "Epidemiologic Studies of Uranium Miners."
This report referenced an earlier NAS-NRC report dated August
1968 titled "Radiation Exposure of Uranium Miners." The con-
clusions of the January 1971 report are set forth below:
In its report of August, 1968, the NAS-NRC Advisory Committee to the
Federal Radiation Council concluded as follows:1
"(a) There appears to be a casual association between lung cancer and
exposures of approximately 1,000 CWLM and higher.
" (b) There is a statistically significant increase in the lung cancer risk for
miners with approximately 100 to 400 CWLM exposure that cannot be ex-
plained by any known artifact of the data.
" (c) The hypothesis is favored, pending more definitive data, that radiation
exposure at least contributed to the excess lung cancer observed in miners in
the 100 to 400 CWLM category."
The Analyses in the present PHS report strengthen the conclusions of the
previous NAS-NRC Committee. Of particular significance are the following:
1. With further accumulation of data, an increased lung cancer risk con-
tinues to be seen for miners in the 120-359 CWLM category.
2. This increase is seen using a variety of analytic methods, based on dif-
ferent assumptions. In spite of intensive study, no likely source of error or
bias that could account for the increase has been identified. In particular,
cigarette smoking does not account for the excess. Certain biases that have
been identified are in the direction to suggest that radiation exposure may
have been overestimated and that therefore the effect observed may in fact be
attributable to doses lower than those of the 120-359 CWLM category. There
is no evidence that these bases affect differentially miners who have or have
not developed lung cancer.
3. Up dating and improvement in the quality of the data on exposure levels
has eliminated apparent irregularities in the dose-response relationship in the
lower dose categories seen in previous analyses.
4. An independent review of the histologic characteristics of the lung
tumors in miners and appropriate controls using a careful statistical design
and conducted on behalf of the PHS interagency review group has confirmed
the earlier finding of Saccomano and others that the particular form of lung
cancer that occurs in excess in miners exposed to high doses is also in excess
among cases occurring in miners exposed to the lowest categories of dose.
5. The Ad Hoc Committee reaffirms the statement of the 1968 National
Academy of Sciences-National Research Council Committee quoted above.
This conclusion is unanimous.
1 "Radiation Exposure of Uranium Miners." A report of an Advisory Committee from the
Division of Medical Sciences: National Academy of Sciences-National Research Council-Na-
tional Academy of Engineering, Federal Radiation Council, Washington, B.C., August 1968,
p. 24, paragraphs 7, 8.
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1428 LEGAL COMPILATION—RADIATION
IUMRRG SUBGROUPS
The IUMRRG established subgroups to carry out various tasks.
These tasks and a brief summary of the conclusions of the sub-
groups were:
I. Health effects. Subgroup IA: Task—Review and update the
U.S. Public Health Service epidemiologic study of underground
uranium miners in accordance with the advice and recommenda-
tions of an ad hoc committee of the National Academy of Sciences-
National Research Council (NAS-NRC), set up at the request of
the FRC.
Conclusions: Unanimously agreed with the conclusions of the
NAS-NRC report (set forth above).
Subgroup IB: Task—Review all appropriate experimental and
epidemiological studies, including published and unpublished in-
formation on the induction of lung cancer by radiation, and review
theoretical considerations related to the epidemiological exposure
units of WLM to the radiation protection units of rads and rems to
critical tissues.
Conclusions: The bronchial epithelium is a relatively sensitive
tissue with respect to radiation induced cancer; radiation is the
major identified carcinogenic agent associated with lung cancer
in uranium miners and that a standard greater than 4 WLM per
year probably would result in dosages to the critical tissues of lung
exceeding dosages permitted for other occupational radiation ex-
posure situations.
II. Monitoring, exposure and mining practice. Task—Analyze
data on industry performance in controlling radon daughter con-
centrations in mine air using Department of Labor Inspection data,
U.S. Bureau of Mines inspection data and State records.
Conclusions: Most of the industry is now meeting a 12 WLM
per year standard and data indicate that it is feasible to reduce
exposures to 4 WLM per year with current technology. However,
it recommended that a sufficient time to achieve compliance be al-
lowed, if an exposure standard of less than 12 WLM is adopted.
III. Economics. Task—Examine the economic impact of pro-
posed annual exposure standards set at 12 WLM, 8 WLM, and 4
WLM. In carrying out this particular phase the FRC contracted
with Arthur D. Little, Inc., for an evaluative report.
Conclusions: Technology is available by which the industry can
achieve a 4 WLM per year standard and such a standard would
not have a severe economic impact on the underground uranium
mining industry provided adequate time was allowed for com-
pliance. It concluded that a period of 1 year to achieve an 8-WLM-
per-year standard and 2 years to achieve a 4-WLM-per-year stand-
-------
GUIDELINES AND REPORTS 1429
ard may be reasonable. The report also stated that the effect of a
4-WLM-per-year standard on available uranium reserves would
be a relatively minor reduction, i.e., less than 10 percent.
IV-A. Diagnosis and therapy of lung cancer. Task—Review
information related to diagnosis and treatment of lung cancer, in-
cluding pathological review for cancer cell-type and sputum cytol-
ogy.
Conclusions: Present methods of treatment of lung cancer are
unsatisfactory; sputum cytology and analysis can be useful in the
early diagnosis of lung cancer. Earlier diagnoses might improve
the prospect for cure. It also concluded that there is a demon-
strable relationship between the cumulative exposure level and the
frequency of small cell, anaplastic carcinomas that could not be
attributed to age or cigarette smoking.
IV-B. Radiation concentration and exposure techniques and
equipment. Task—Collect, analyze, and interpret measurement
technology for determining radon and radon daughter concentra-
trations in mine air and potential use of various types of radiation
exposure monitoring devices.
Conclusions: Satisfactory instruments are available for radon
and radon daughter concentration measurement but no personal
monitoring devices are available at the present time.
PUBLIC COMMENT
All reports referred to above are to be found in EPA Headquar-
ters located at 1626 K Street NW., Washington, B.C., telephone
(202) 632-7792 and the 10 Regional Offices located at:
-------
1430
LEGAL COMPILATION—RADIATION
REGION
ADDRESS
II
III
IV
V .
VI ..
VII .
VIII
IX ..
X ...
TELEPHONE
NO.
John F. Kennedy Federal Bldg., 617—223-6884
Boston, MA 02203.
26 Federal Plaza, New York, NY 10007. 212—264-2525
401 North Broad St., 215—597-9151
Philadelphia, PA 19108.
50 7th St. NE., Atlanta, GA 30323. 404—526-5215
433 West Van Buren St., 312—353-5264
Chicago, IL 60607.
1114 Commerce St., Dallas, TX 75202. 214—749-2827
610 East 12th St., 816—374-3038
Kansas City, MO 64106.
Federal Office Bldg., 303—297-4457
19th and Stout St., Denver, CO 80202.
760 Market St., 415—556-4303
San Francisco, CA 94102.
1319 2d Ave., Seattle, WA 98101. 206—442-0530
All interested persons who desire to submit written comments
for consideration in connection with this matter should send them
to the Administrator, EPA, Washington, D.C., 20460, within 30
days after publication of this notice in the FEDERAL REGISTER.
Comments received after that period will be considered if it is
practicable to do so, but assurance of consideration cannot be given
except as to comments filed within the period specified.
Dated: May 19,1971.
WILLIAM D. RUCKELSHAUS,
Administrator.
4.3d RADIATION PROTECTION GUIDANCE, UNDERGROUND
MINING OF URANIUM ORE, ENVIRONMENTAL
PROTECTION AGENCY,
July 9, 1971, 36 Fed. Reg. 1292 (1971)
UNDERGROUND MINING OF URANIUM ORE
RADIATION PROTECTION GUIDANCE FOR FEDERAL AGENCIES
On May 25, 1971, the Environmental Protection Agency pub-
lished a notice in the FEDERAL REGISTER (36 F.R. 9480) concerning
guidance for the protection of underground uranium miners. The
notice stated: "The Administrator does not find a basis for mod-
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GUIDELINES AND REPORTS 1431
ifying the guidance approved by the President that an annual
exposure level of 4 WLM be effective as of July 1, 1971." The
notice also stated that "All interested persons who desire to submit
written comments for consideration in connection with this matter
should send them to the Administrator, EPA, Washington, D.C.
20460, within 30 days after publication of this notice in the FED-
ERAL REGISTER. Comments received after that period will be con-
sidered if it is practicable to do so, but assurance of consideration
cannot be given except as to comments filed within the period
specified."
All written comments received on or before June 28, 1971, have
been reviewed. Letters of comments have been received from in-
dustry, other Government agencies and a labor union. These
comments are available for inspection at EPA Headquarters, 1626
K Street, NW., Washington, DC 20460.
Several questions were raised on the scientific basis for setting
the guidance of 4 WLM per year and in particular challenged the
validity of the PHS epidemiologic report.
The Environmental Protection Agency has fully considered the
methodology of the PHS epidemiologic study on uranium miners
as well as the limitations of the study data for the setting of stand-
ards for underground uranium miners.
In addition EPA has evaluated a considerable body of other
scientific information, both experimental and epidemiologic, avail-
able on radiation induced lung cancer for its relevance to establish-
ing radiation protection guidance for uranium miners. EPA has
also taken into account reports from several expert and advisory
groups * established to review and interpret the problem of radia-
tion induced lung cancer.
Based on the reports of these expert groups and the other con-
siderations noted above, EPA concludes that guidance not to exceed
4 WLM per year is warranted in order to afford adequate radiation
protection of uranium miners. Furthermore, it is emphasized that
the exposure levels of concern are not "low" in the context of usual
occupational radiation protection practices; an annual exposure
greater than 4 WLM would probably result in a dose in rems to the
critical tissue of the lung that exceeds the occupational radiation
standard generally accepted in the nuclear industry.
Therefore, it has been concluded that the comments suggesting
1 The DHEW review group. May 1967; (2) NAS/NRC Advisory Committee to FRC 1968;
to FRC 1968; (3) NAS/NRC Advisory Committee to FRC, 1970/71; (4)
Subgroups I-A and I-B of the Interagency Uranium Mining Radiation
Review Group, 1970/71; (5) NCRP Report 39, 1971; and (6) ICRP Publi-
cation 14,1969.
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1432 LEGAL COMPILATION—RADIATION
that EPA should recommend less stringent radiation protection
guidance than the present 4 WLM per year do not provide an
adequate basis for doing so. Accordingly, EPA does not recom-
mend any change in the guidance approved by the President and
published in the FEDERAL REGISTER (34 F.R. 576, 35 F.R. 9218) of
4 WLM per year effective July 1, 1971.
Several comments were received which referred to the means of
implementing the 4 WLM guidance. As the May 25, 1971, FED-
ERAL REGISTER notice indicated, decisions concerning the means of
implementing the guidance for uranium mines, including any pro-
cedures for variances which may be made available to individual
mining operators, must be made by the regulatory agencies which
adopt this guidance. It should be noted that the Secretary of the
Interior on June 30, 1971, signed proposed amendments to regula-
tions under the Federal Metal and Nonmetallic Mine Safety Act.
These proposed amendments relate to variances applicable to
underground uranium mines. EPA will provide such comments
as it deems appropriate on these proposed amendments directly
to the Department of the Interior at a later date. Copies of all of
the comments which EPA has received in response to the May 25,
1971, FEDERAL REGISTER notice and copies of this FEDERAL REG-
ISTER notice have been sent to the Secretaries of the Interior and
Labor under cover of a letter dated July 1, 1971.
Dated: July 1,1971.
WILLIAM D. RUCKELSHAUS,
A dministrator.
[FR Doc. 71-9697 Filed 7-8-71; 8:49 am]
4 U. S. GOVERNMENT PRINTING OFFICE : 1973 O - 469-517 (VOL. I]
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