ML19220A228
| ML19220A228 | |
| Person / Time | |
|---|---|
| Issue date: | 11/30/1975 |
| From: | NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | |
| Shared Package | |
| ML19220A229 | List: |
| References | |
| TASK-OH-902-4, TASK-OS 80806, 80824, REGGD-08.013, REGGD-8.013, NUDOCS 7812190209 | |
| Download: ML19220A228 (6) | |
Text
November 1975 Revision 1 U.S. NUCLEAR REGULATORY COMMISSION PdGU LE'ORY GJDE OFFICE OF STANDARDS DEVELOPMENT REGULATORY GUIDE 8.13 INSTRUCTION CONCERNING PRENATAL R ADI ATION EXPOSURE A. INTRODUCTION than an adult, particularly during the fhst thiec months after conception, when a woman may not be aware that Section 1912 of 10 CFR Part 19 states that all she is pregnant, the National Couned on Radiation individuals working in or frequentmg any portion of a Protection and Measurements (NCRP) recommended in restricted area must be instructed in the health protec-its Report No. 39 that special precautions be taken to tion problems associated with exposure to radioactive limit exposure when an occupationa'ly exposed woman materials or radiation. This guide describes the instruc-could be pregnant.
tion that should be provided concerning biological risks to embr)os or fetuses resultmg from prenatal exposure
- C. REGULATORY POSITION Instruction to workers performed under 19.12 B. DISCUSSION should be given prior to as:ignment to work in a restricted area. In providing instruction about health Since the Law of Bergonie and Tribondeau was protection problems associated with radiation exposure, published in 19iL " it has been known that the female workers and those who may supervise or work sensitnity of cells to radiation damage is related to their with them should be givan specific instruction about reproductive activity and inversely related to their prenatal exposure risks to the developing embryo and depee of differentiation. It follows that children could fe t us.
be ex pected to be more radiosensitive than adults.
The instruction should ensure that the employees fetuses more radiosensitive than children, and embryos esen more radiosensitive.
understand:
1.
That the NCRP has recommended that, during This principle has long been a factor in the the entire gestation period, the maximum permissible deselopment of radiation exposure standards. Section dose equivalent to the fetus from occupational exposure 20.104 of 10 CFR Part 20 places different limits on of the expectant mother should not exceed 0.5 rem and minors than on adult workers. Specifically, it limits anyone under the age of 18 to exposures not exceeding 2.
The reasons for this recommendation.
103 of the lirnits for adult workers. Iloweser. 20.l M does not relate to embryos or fetuses.
The instruction should include the informatir'n provided in the Appendix to thk guide. It should be A special situation arises when an occupationally presented to the employee, her supervisors, and her exposed woman is pregnant Exposure of the abdomen c o-wo rker s both orally and in written form. Each of such a worker to penetrating radiation from either individual should be given an opportunity to ask external or internal sources would also imolve exposure questions, and each indisidual should be asked to d the embryo or fetus. Because a number of rtudies acknowledge in writing that the instruction has been hne indicated that the embr> o or fetus is more sensitive received.
' I his re s i&n the rmJe inhin nunor t hanges of a D. IMPLEMENTATION tlant>ing r.nure :nwrFrated as a remit of puNh comments w substanme aances base hen nude The Yurpose of this section is to provide inf orma-
- *Comptes Rendus des Scances de I AcaJcmw Jes Smnces. VM tion to licensees regarding the use of this guide.
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E uept in those cases in wh!:h the licensee chooses frequenting any portion of a restricted area, and those to propose a i alternative method for complying with the who may supervise or work with such employees portion of the Commission's regulations previously concerning the health protection problems associated s;uified, the methods desenbed herein should be used with prenatal radiation exposure.
immediately to instruct female employees workingin or
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U.S. NUCLEAR REGULATORY COMMISSION APPENDIX TO REGULATORY GUIDid 8.13 POSSIBLE HEALTH RISKS TO CHILDREN OF WOMEN WHO ARE EXPOSED TO RADIATION GURING PREGNANCY Some recent studies have shown that the risk of All Nuclear Regulatory Comnussion licensees are leukemia and other car >cers in children increases if the now required
- to inform all individuals who work in a mother is expoed to a significant amount of radiation restricted area of the health protection problems asso-during pregnancy. According to a report by the National ciated with radiation exposure. This instruction would in Acadeiny of Sciences, the incidence of ieukemia among many cases include information on the possible risks to children from birth to 10 years of age M the United unborn babies. The regulations also state " that States could rise from 3.7 cases in 10,000 crnldren to 5.6 licensees should keep radiation exposures as low as is cases in 10,000 children if the children were exposed to reasonably achievable. According to the National I rem of radiation before birth (a " rem"is a measure of Council on Radiation Protection and Measurements.
radiation). The Academy has also estimated that an vigorous efforts should be made to keep the radution equal number of other types of cancers could result exposure of an embryo or fetus at the very lowest from this level of radiation. Although other scientiGe practicable level during the entire period of pregnano.
studies have shown a much smaller effect from radiation, the Nuclear Regulatory Commission wants women em-Thus it is the responsibility of your employer to playees of its licensees to be aware of any possible risk take all practicable steps to reduce your radiation so that the womer, can take steps they think appropriate exposure. Then it is your responsibility to decide to protect their offspring.
whether tne exposure you are receiving is sufficiently low to protect your unbom child. The advice of your As an employee of a Nuclear Regulatory Cammis-employer's health physicist or radiation protection sion licensee, you may be exposed to more radiation officer should be obtained to determine whether radu-than the general public. Ilowever, the Nuclear Regula-tion levels in your working areas are high enough that a tory Commission has estabbshed a basic exposure limit baby could receive 0.5 rem or more before birth. If so, for all occupationally exposed adults of 1.25 rems per the ahernatives that you might want to consider are:
calendar quarter, or 5 rems per year. No clinical evidence of harm would be expected in an adult working within (a) If you are now pregnant or expect to be soon, these levels for a lifetime. Because the risks of undesir.
you could decide not to accept or continue assignments able effects may be greate for young people. ind2viduals in these areas.
under 18 years of age are permitted to be exposed to only 10 percent of *.he adult occupational limits. (This (b) You could reduce your exposure, where possi-lower hmit is also applied to members of the general ble, by decreasing the amount of time you spend in the public.)
radiation area, increasing your distance from the radu-tion source, and using shielding.
The scientific organization called the Na tional Council on Radiation Protection and Measurements has (c) If you do become pregnant, you could ask y our recommended that because unborn habies may be more einployer to reassign you to areas involving less exposure sensitive to radiation than adults, their radiation dose as to radiation. If this is not possible, you might consider a result of occupational exposure of the mother should not eweed 0.5 rem. Other scientifie groups, including the International Commission on Radiation Protection.
- b I nie m. rm W or & Ne W t nicM Rnutmons base also stressed the need to keep radiation doses to unborn tinldren as low as is reasonably achievable.
"In rnie 10. Part 20.
144 174
lening your job. If you decide to take such steps. do so without delay. The unborn ch:Id n most sens: tis e to lhe amunt of raJiation an mdiudual retenes n radiation du-ing the first three months ut y our preg-ca]!ed the,,dow and is measured m,, rems, T,u nanc\\'
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v erao indwidual in the United States aaumulates a dose of one rem from natural sources esery 12 yew (d) i.ou could delay havmg shildren untd you are 1he dose from natural radiation is higher in some states.
no longer working in an area where the radiation dose to sush as Colorado. Wy oming. and South Da.ota pn.
y our unbotn baby could enced U.5 rem.
manly because of cosmic radiation There the aserace indnidual gets one rem oery n scars T.ou may also, of course, choose to Natural background radiation lesels are also much (c) Contmue working in the higher radiation areas, hither m certain local areas. A dose of one rem mn be t,ut with full awareness that you are doine so at some re2ened in some areas on the beach at Guarapan. Bran!
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smAl mereased risk for your unborn chi!d.
m only about 9 day s, and some people in Kerala,Indu.
get a dose of one rem every ^ months.
The following facts should be noted to help you make a Many people receive additional radiation for medi decismn cal reasons. In 1970, an estimated 212 million Eray examinations were perfonned in the Umted States. The estimated aserage surface skin dose from one radio 1.
The h,rst three months of pregnancy are the graphic chest b.ay is 0.027 rem. T he estimated aserag most important, so y ou should make your decision surface skm dose per abdominal b. ray is 0.62 rem.,
quickly.
R di tion can also be receneJ from natural sourecs 2.
In most cases of occupational exposure, the actual dose received by the unborn baby is less than the such as rock or bnek structures, from consumer proJ-dose receised by the mother because some of the dose is ucts such as telesision and p, low in the. dark watches absorbed by the mother's body.
and from air travel. The possib!c annual dose f rom working 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> day near a granite wall at the Pedcap 3.
At the present occupational exposure limit, the Stand in Grand Central Station New York City. is 0.2 actual risk to the unborn baby is small, but experts rem, aad the average annual dose in the Umted States disagree on the exact amount of nsk.
frorn W c nsumer products, and air trasel is 0.002n
- rem, 4 There is no need to be concerned about sterility or loss of your abdity to bear children, The radiation Radiation, hke many thmgs, can be harmf ul. A larp dose required to produce such effects is more than 100 dose to the whole body (such as 600 rems in ont day 1 times larger than the Nuclear Regulatory Commission's would probably cause deaih in about 30 days. but such
! rge doses result only from rare aceiJents. Control of dose iimits for aduhs exposure to radiation is based on the assumption that ny exposure, n matter how small, insohes some risk.
5.
Even if you woik in an area where you receise The occupational exposure limits are set so low, how-onle 0.5 rem per three-month period, in nine months ever, that medical esidence gathered eser the past 50 you could receise 1.5 rems, and the unborn baby could years indicates no chnically observable injuries to mdn receive more than 0.5 rem, the full-term hmit suggested viduals due to radiation exposures when the estabhshed by the NCRP. Therefore, if you decide to restrict your radiation limits are not exceeded.This was true esen f or unborn baby,s exposure as recommended by the N(.RP, exposures received under the early occupational er be aware that the 0.5 rem limit to the unborn baby posure limits. which were many times higher than thc applies to the full rune-month pregnancy.
present h mit s.
Thus th; risk to indinduals at tia occupational exposure levels is considered to be sery Iow. Iloweser,it is impossible to say that the usk is zero The remainder of this document contains a brief.
To decrease the risk still further, licensees are expected explanation of radiation and its effects on humans. As to keep actual exposures as far below the limits as n y ou will see, some radiation is present every where and onably achievable.
the levels of radiation most employees of Nuclear Regulatory Commission licensees receive are not much larger than these natural lesels Because the radiation les els in the facihty wherc you wdl be working are Pf ' N C icd 'C R C P""
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I sm utes o t w.4 anJ 19 5 Genenalb s ndham hm required by law to be kept quite low, there.is 001
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.ma w en.ne. Pm Heanh serme. l eJeral Drn sJoann u adult employ ees.
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The current exposure limits for people working with Summary radiation have been developed and carefully reviewed by nationally and intemationally recognized groups of Occupational exposures to radiat!on are bemg kept scientists. It must be remembered, however, that these low. However, qualified scientists have recommended limits are for adults. Special consideration is appropriate that the radiation dose to an embryo or fetus as a result when the individual being exposed is, or may be, an of occupational exposure of the expectant mother expectant mother, because the exposure of an unborn should not exceed 0.5 rem because of possible increased child ray W.a be involved.
risk of childhood leukemia and cancer. Since this 0.5 rem is lower than the dose generally permitted to adult w rkers, women may want to take special actions to Prenatal Irndlation avoid receiving higher exposures, just as they might stop sm ng g pregnancy or - @ cM nab more The prediction that an unborn chud would be more carefuuy t reduce possible rhks to their unborn sensitive to radiation than an adult is supported by chudren.
observations for relatively large doses. Large doses delivered before birth alter both physical development and behador in experimentally exposed animals. A Bidography report of the National Academy of Sciences states that short. term doses in the range of 10 to 20 rems cause 1.
Donald G Pizzarello and Richard L Witcofski, subtle changes in the nerve cells of unborn and infant Basic Radiation Biology, Philadelphia: Lea and rats. The report also states, however, that no radiation Febizer,1967.
induced changes in development have been demon-strated to result in experimental animals from doses up 2.
National Academy of Sciences - National Research to about I rem per day extended over alarge part of the Councu, ne Effects on Populations of Exposure to period before birth.
Low Le>els of Ionizing Radiation, Washington, D.C., November 1972.
The National Academy of Sciences also noted that doses of 25 to 50 rems to a pregnant human may cause 3.
National Counc0 on Radiation Protection and Mea-growth disturbances in her offspring. Such doses sub-surements, Basic Radiation Protection Otteru, stantially exceed, of course, the maximum permissible NRCP Report No. 39, Washington, D C., January occupational exposure limits.
15,1971.
Concem about prenatal exposure (i.e., exposure of a 4 United Nations, Iontring Radiation-Levels and child while in its mother's uterus) at the permissible Effects, 2 vol., Reports cf the United Nations occupational levels is primarily based on the possibuity Scientific Committee on the Effects of Atomic that cancer (especially leukemia) may develop during the Ratation, Report No. A!8725, United Nations, first 10 years of the child's life. Several studies have been New York,1972.
performed to evaluate this risk. One study involved the followup of 77,000 children exposed to radiation before 5.
U.S. Atomic Energy Commission, Division of Tech-birth (because of diagnostic abdominal X. rays made for nical Information, Understanding the Atom Series:
medical purposes during their mother's ptegnancy).
Another study involved the followup of 20,000 such Atoms Nature and Man children. In addition, 1292 children who received prenatal exposure during the bombing of Hiroshima and De Genetic Effects of Radiation Naga*aki were stud!ed. Although contradictory resulta nave been obtained, most af the evidence suggests a ne Natural Radiation Ennronment relationship betwten prenatal exposure and an increased it1k of chDdhood cnneet.
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