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896 SA MEDIESE TYDSKRIF 5 DESEMBER 1981

appeared to be adequate in the one case in which it was applied(worker G), being combined with other laboratory tests before adecision was raken.

AddendumAs of June 1981 a ZPP reading of 20 j.1g1g Hb, thought tocorrela te with a Pb-B value of 70 j .1g1dl, was adopted as thecriterion for removal from exposure.

REFERENCESI. Zielhuis, R. L. and Wibowo, A. E. E. (1978): Ned. T. Geneesk., I22, 793.2. Waldron, H. A. (1978): J . soc. Occup. Med., 28, 27.3. Moore, M. R., Campbell , B. C and Goldberg, A . ill Lenihan, J. and Fletcher,W. W., ed. (1977): The Chemical Em,iromnenr (Environment and Man, vol. 6),p. 89. Glasgow: Blackie & Son.4. Commission of Inqui ry on Occupat iona l Heal th (1976): Repor t (RP 55).Pretoria: Government Printer.

5. Proceedings of the 1974 Confe rence on Standards of Occupational LeadExposure (1975): J. occup. Med., 17,98.6. Gross, S. B. (1979): Oral and [nhalarion Lead Exposllres in Hi/man SlIbjecrs.New York: Lead Industries Association, Inc.7. Hernberg, S. in Zenz, C, ed. (1975): Ocwparional Medicine, Principles andPracrical Applicarions, chapt. 30. Chicago: Yearbook Medical Publishers.8. Irving, L. M., Harrison, W. 0. , Webster, 1. er 0/."(1978): Lancet, 1,4.9. Lane, R. E., Hunter, D., Malcolm, D. er at. (1968): Brit. med. J., 4, 501.10. Baker, E. L., Landrigan, P. J., Harbour, A. G. er at. (1979): Brit. J. industr.Med., 36, 314. .11. Hammond, P. B., Lerner, S. J., Garrside, P. S. er al. (1980): J. occup. Med., 22,475.12. World Health Organization (1977): Lead (Environmental Health Criteria, no.3). Geneva: WHO.13. Benson, G. J., George, H. H. S., Lichfield,M. H. er al. (1976): Brit. J. industr.Med., 33, 29.14. Piomelli, S., Davidow, B., Guinee, V. F. er al. (1973): Pediatrics, SI , 254.15. Lamola, A. A., Joselow, M. and Yamane, F. (1975): Gin. Chem., 21, 93.16. Tomokuni, K., Osaka, 1. and Ogata, M. (1975): Arch. environm. Hlth, 30, 588.17. Fischbein, A., Eisinger, J. and Blumberg, E. W. (1976): Mt Sinai J. Med., 43,294.18. Joselow, M. M. and Flores, G. (1977): Amer. industr. Hyg. Ass. J., 38,63.19. Herber, R. F. M. and Wibowo , A. E. E. (1980): T. soc. Geneesk., 58,425.20. Grandjean, P. (1979): Bri t. J . industr . M.ed., 36, 52.21. Zielhuis, R. L. and Wibowo, A. E. E (1978): T. soc. Geneesk., 56, 676.22. lee, W. R. (1981): J . ray. CoIl. Phyens Lond., 15,48.23. Hesley, K. L. and Wimbish, G. H. (1981): Amer. industr. Hyg. Ass. J.,42,42 .

Medicalnuclear

standards forinstallations

workers In

L. C. VAN OUDENHOVE DE ST G ~ R YHistorySummary

South Africa is moving into the nuclear energy age,and most practitionersare probably notaware of theimplications in medical practi ce. The demandsupon workers in this area are very s tr ic t, and thedoctor who may have to examine them must beaware of this. This art ic le is designed to outline theprocedures necessary in examining candidates foremployment in the nuclear energy industry.S. Atr. med. J., 60,896 (1981).

Very strict international srandards have been established fornuclear personnel and made applicable by the Atomic EnergyBoard to any South African l icence holder (corpora te orindividual).The basic investigation of any candidate for employment in anuc lear plant as a ' rad iat ion worke r' consists of a personalhistory, physical examination and complementary examinations.

809 Medical Centre, Hererengracht" Cape TownL. C. VAN OUDENHOVE DE ST GERY, M.D.Date received: 21 April 1981.

Only persons over the age of 18 may be employed at nucl ea rinstallations and, in principle, women under the age of 50 cannotbe employed as rad ia tion workers at nuclear insta lla tions ,although of course they may be employed in departmentsoutside.A complete family history is necessary as well as a history ofprevious work with particularattention to toxic,dusty, noisy ~ glary jobs and anyprevious exposure to ionizing radiation (which

would include any exposure to medical radiological apparatus).All dosimetric information must be recorded accurately andt ransmi tted to an accredi ted health physic is t. In taking thepatient's history, it is important to,remember that every detail iswonh taking note of and that enquiry must be madesystematically, system by system.Every exposure of skin to toxins and dust must be noted, withspecial reference to chronic skin disease of any nature that couldbe made worse or reactivated by ionic radiation. Inability to rrear

any skin condirion successfully is ground for rejection, and anyskin change due to previous radiation constitutes ~ absolutecontraindication to employment.Cardiovascular system. As regards the cardiovascularsystem all the' conventional contraindications to industrial

employment are valid, for the principle involved is not so muchthat these constitute a bar to employment bu t that the work in anU,clear installation requires the most complete state of fitnesspossible. Any chronic disease of the respiratory system that

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could enhance the danger of internal contamination or beaggravated by such contamination is a contraindication.Digestive system. Basically, disorders of the disgestivesystemwhich are conrraindications ro work in a nuclearplantarethe same as those in normal industry; i t is clear that chronicinte tinal ulceration or any chronic inflammarory conditionwould be a contraindication ro acceptance. In s o ~ e cases the

candidate may be reviewed 3 months later, after treatment.Nervous system. The condition of the nervous system mustbe carefully reviewed and in doubtful cases the candidate shouldbe referred for neurological, psychological or psychiatricinvestigation. The emotional balance of the worker is of primaryimportance, as is his ability ro observe strict discipline and workin a team.Renal d i s e a s ~ is usually a bar to employment.Ears, nose a nd throa t. Any previous chronic or acuteinflammatory condition affecting the ear, nose and throat mustbe enquired after and if necessary treated before a final decisionabour employment. Hearing must be tested.Endocrine s ys tem. I n the endocrine system the cri ticalorganis the thyroid, on accounr of possible contamination byi od in e-13 1. Unc on tr ol le d d ia be te s is an absolute

contraindication.Scars and wounds. Surgical scars must be investigated fromtwo angles: (1) a surgical scar implies previous disease, aboutwhich enquiry should be made; and (ii) any scar enhances theeffect of contamination and is a handicap to deconramination.Any wound that may cause problems with ske le ta lcontamination is a reason for temporary exclusion fromwork in aradiation or contamination zone. Special attention must be paidro fractures, especially recent fractures, on account of thestrontium-90 effect- on callus. The presence of any malignanttumour, past or present, constitutes an absolute contraindicationro employment.

The blood. Enquiry must be made into any past disorder ofthe blood in the applicant or his family; this is an area requiringcareful inves tiga tion, s ince any blood disorder const itutes acontraindication ro radiation work. Enquiry must also be madeabout previous radiotherapy, and the dosimetric results must becommunicated to and discussed wi th an accredited heal thphysicist.

Clinical examinationThis must be prolonged, complete and systematic; in viewof theresponsibility involved and the rules that must be strictly appliedto new workers , this examinat ion can never be too strict.

Skin. Any skin lesions must be looked for, especially on theface, scalp, neck, hands and trunk. Chronic and resistant acne, ifwidespread, constitutes a reason for rejection because of the riskof repeated contamination of the area. Skin tumours ordegenerative changes in the skin should be carefully noted. I f thecandidate shows signs of bit ing his nails, he must be warnedabout the dangerof contamination through this and rejected ifhepersists with the habit. Skin lesions due to radiation mayconstitute a reason for temporary or permanent suspension.

Cardiovascular system. Examination of the hear t andblood vessels is the same as in general medical examinations, burit. is useful to have a pre-employment ECG and to repeat this atintervals.

Examination of th e respiratory system is basically thesame as in all industrial medicine, bur in addition lung capacitymust be assessed. Chronic bronchitis, asthma or emphysema is areason for rejection, and tuberculosis is of coursea complete bar.

Abdomen. Apart from general abdominal examination, careshould be taken to look for hernias, liverenlargement and splenicenlargement, all of which are grounds for rejection. Anyinterruption of the mucosa membrane of the gastro-intestinaltract such as a pepticor intestinal ulcer is a contraindication. Th e

SA MEDICAL JOURNAL 5 DECEMBER 1981 897

urinary and genital systems must also be investigated.Ears, nose and throat. Chronic infections of the throat ornose constitute reasons for rejection. The condition of the ears

must be looked inro, with particular emphasis on perforation ofthe eardrum. Any perforation or chronic inflammation of theexternal audirory meatus is ground for reject ion unless theindividual undergoes a successful tympanoplas ty or othercurative operation. Basic hearing capacity must be tested; if indoubt the candidate must be referred ro an E T specialist. Inany case an audiogram is obtained annually. Loss of20 dB at theentrance examination makes a candidate unacceptable.

Eyes. There are no actual standards for visual acuiry, but thegeneral rule is that if the candidate is wearing glasses he shouldbe able to executeessential manoeuvres at his place ofwork in theshortest possible time even under the most complexcircumstances, and he must be able to wear a mask or otherprotective gear prescribed for work in contaminated areas.Glasses may be replaced by special plastic unbreakable glassesadapted to the protective gear. Certain jobs such astelemanipulations in a hot cell or in the fuel pool demand perfectvision and absolute depth dimension view. The importance ofcolour vision varies from department to department and fromjob to job. Colour blindness would not const itute an absolutefactor for disqualification and must be weighed up against thedemands of the job. Th e significance of narrowing of the visualfield would depend upon the tasks ro be performed and the causeof the impairment.

Nervous system. The neurological balance sheet is probablythe most important part of a pre-employment examination. Anyserious abnormality constitutes an absolute contraindication,and this includes the psychological field, in whichclaus trophobia, for example, would disqualify a radiationworker. Balance is of particular importance since the workermust be able ro climb steps and ladders and work at heightswithout danger to himself, and any candida te with at tacks ofdizziness or fainting would therefore be disqualified. Since mostworkers must be able to do shift work disorders of sleep willconstitute a bar, and any lackof co-ordination and reaction speedalso disqualifies him.

Female personnelFor obvious reasons it is the general policy nor to employ females ta ff in a radia tion area. If they have to be employed womenshould be examined just as systematically as men, and agynaecological examination should be performed if there is anyindication of uterine or ovarian disease or of pregnancy. Mostfemale personnel are of course employed ourside the controlledzone; nevertheless for medical, legal and psychological reasons itis highly advisable not to employ female staff without an initialcomplete medical balance sheet, as well as repeat examinationswhen required.

Complementary examinationsThese examinations are intended to cover the special risks andresponsibilit ies in a nuelear installation and are therefore asimportant as, if nor more importanr than, the general clinicalexamination. Two of the systemic examinations are compulsory(the biological balance sheet and the ophthalmological balancesheet) and one is optional (chest radiography).

Biological balance sheetThe most important component of the biological balance sheetis the haematological examination. This will include a completeblood co-unt and the other standard haematologicalexaminations. The red cell count should not be below 3,8 x

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898 SA MEDIESE TYDSKRIF 5 DESEMBER 19811Q6/J.Ll or above 5,5 x 1Q6/J.L1. The total white cell count shouldnot exceed 12000/I.Ll or fall below 4000/J.Ll. Blood tests shouldbe carried out twice, once with the candidate fasting and onceafter breakfast. The polymorphonuclear count should bebetween 35% and 80% of the total white cell count. Haemostasis(coagulation, bleeding time, etc.) should also be studied . Anyabnormali ty requires investigation as to its cause andconsequences.

The blood sugar and blood urea levels should be estimated.Renal function should be studied by chemical and cytologicalexamination of freshly passed urine, an Addis count and urea andcreatinine clearance tests whenever possible; these aremandatory if any abnormality or suggestion of abnormality ispresent.The legal justification for this emphasis on the haematologicalexamination is the extreme sensitivity of the haematopoieticsystem to ionizing radiation. The acceptable standards are thoseestablished by the International Atomic Authority madeapplicable within South Africa by the Atomic Energy Board(AEB) in Pretoria. Medically acceptable standards are set by thelaboratory and will provide guidance for the approved doctor'sdecision; however, they are not hard and fast, since one must takeinto account changes caused by passing events and diseases.\Vhenever results are outs ide the accepted standards , the

examination should be repeated after 2 - 3 weeks and wheneverpossible a reason for the abnormali ty should be established. Ifresults are abnormal on three successive occasions the candidateshould be declared unfit for work as a classified radiation worker.

Ophthalmological balance sheetThis should preferably be d rawn up by an ophthalmologistchosen by the approved medical practitioner and include a study

of visual acuity with or without correction, the fundi, intraocular pressure, and biomicroscopic examination of thecrystalline lens. These last two examinations are of imponancesince it must be accepted that any irradiation, especially withneutrons, may produce a cataract . Exposure of an eye withincreased intra-ocular pressure to ionizing radiation will quicklyworsen the condition. Both glaucoma and cataract are completebarriers to radiation work.

Chest radiographyA chest rad iograph is essential to exclude any form oftuberculosis and should only be omitted if clinical examinationhas shown beyond any doubt the absence of pulmonary disease

and if t he worker has been or will be exposed to substantialradiation.

ResultsWhen the personal ques ti onnaire has been complet ed, theclinical examination concluded and the results of all the otherexaminations received, the approved doctor must, as elsewherein industry, decide whether other investigations are required.For instance, when there is a hea ring defect he may refer thecandidate to an otorhinolaryngologist of his choice, or tocomplete the biological balance sheet he may request a glucosetolerance test or liver or respiratory function tests. \Vhen there isa possible abnormali ty in the nervous system, the doctor mustdecide whether it is necessary to refer the candidate to aneurologist, a psychiatrist or a psychologist.

The primary duty ofan approved medical officer to a nuclearplant is to respect all rules, prescriptions and standards laid downinternationally and regularly amended, and to apply these rulesas prescribed by the International Atomic Authority and madeapplicable within South Africa by the AEB, so that..the licence to

operate a nuclear installat ion may be maintained. The secondduty of the doctor is to perform such re-examinations andcomplementary investigations as he deems necessary, on his ownresponsibility.Certificate of fitness fo r radiation work

I f all the above examinations and investigations have beencompleted, the approved doctor must compile a medical balancesheet from which he canconclude whether the candidate is fit forwork in a nuclear installation. This decision must be fmal and noreasons need be given for it. I t is briefly communicated on apreprinted form without any explanation or justification, bu tshould mention the qualifications for the pOSt in question. Allexamination forms and other medical documents are kept underthe control of the approved medical officer himself.General fitness for work will depend upon the demands oftheparticular post , since often the job will be equivalent to that inanother industrial plant. The appnwed medical officer l1)ust befurnished with a complete job description before the candidatehas been examined or re-examined.

He must also decide on f itness for nuclear risks. I f ,thecandidate is found fit for the three basic risks - radiation,external contamination, and internal contamination- then he isfit for rad ia tion work and any potent ia lly hazardous job in acontrolled zone. If , however, he is unfit for any ofthe three basicrisks, he is not fit to work as a radiation worker but only forspecified jobs in a controlled zone. Ifthe candidate is unfit for thethree basic risks he is unfit even to work in a controlledzone andcan only be employed in the same capacity as an ordinarymember of the public outside this zone.Temporary disqualifications

I f a candidate is found unfit for workowing to some complaintwhich is likely to disappear with or without appropriatetreatment within a relatively short period, the doctor maydeclarethe candidate acceptable after successful treatment. This mighthappen in the case of a patient with acne, for example , or atemporal blood disorder due to an infection. The decision toaccept or defer a worker is the exclusive prerogative of theapproved medical officer of the nuclear installation.Fitness for special operations

In the nuclear industry there are certain routine or emergencyoperations such as refuelling of a power reactor, repair of leaks,or confinement insituations with unusual risk of higher radiationand/or contamination. In these or similar situations the docto,must re-examine the candidates in quest ion, or in cases ofurgency decide by whom and under which circumstances theoperations can be carried out. It must always be kept in mind thatthere is a remote possibili ty that these workers may receiveduring a very short t ime a dose higher than theannual permittedlevel and therefore need subsequent treatment and exemptionfrom radiation work for a period of timeestablished by thedoctorin consultation with an accredited health physicist.

During his period of training or work an approved radiationworker may, whether as a resul t of radiation o r not , developcertain symptoms or disorders. He must then be referred to thedoctor, who in turn must refer to the employee's medical file andbalance sheet and decide whether funher investigations areneeded, whether treatment is required and by whom (theemployee's own doctor or not), and whether the employee'scertificate of fitness as a radiation worker can be maintained,modified or withdrawn.It must be emphasized that all these ruks and indications arenot s ta tic but must be continuously adapted to changes innational or international legislation, evolution in radiobiology

and the introduction of new techniques in industrial medicineand nuclear physics.