opiseettt aeeESAIM LOSE,
-
pesure under extreme conditions, with no correc:
Uve measures taken to reduce internal abserption
of radioisotopes prior ta evacuationof the exposed
people fromthe fallout area. It did not involve the
contaminated pasture-cattle- milk cyele, which
Iivht be an important pathway of radioiodine to
tan in other types of accidents (such as the Wind-
scale accident). !74
Civil Defense planning can provide for several
tueasuces that will rechuce the hacard af thyroid
exposure due to radigiodine absorption and thus
largely preclude the degree of thyroid tajury sustuined by the Marshallese. Since Che hazard fromm
radiviadine is acute for a pertad only of days,
carly protective measures are extremely tinportant. Vhese inchude avoiding tibalation of radio-
todines by shelter protection, Cousumung food and
water only from closed containers; feeding cows in
contaminated areas protected fodder; and tem-
purarily withholding contaminated milk supplies and diverting them inte processed products
with a shelf life longer than the life of the isotope.
The addition of stable iodine to food or water dur-
ine the first week waulld provide a relatively inex.
pensive method of reducing thvroid uptake of
radioiodines by isotope dilution and saturation
with non-radioactive todine: this should rarely prodlace any serious side cHeets and would be of partier value in children and pregnant women,
When exposure of the thyroid bas already occurred, prophylactic eatment with thyroid hormone, now beige used in the Marshallese, may
help prevent development of thyroid tumors, and
even after tamer development, surgical excision
Inay reduce jortality duc to nnidigaaney,
‘Phe Uivroid effects in the Marshallese were not
anticipated at the tine al the accident or during the
earky veags aflenwards. bi retrospect this is not surprising, for several reasons. Nt that time the thy.
raid was thought to be relatively racioresistant,
particubirly with regard to radioiodine esx posure
ton the basis of inaat studies and diagnaste and
therapeutic useof FUP ia people. and the calou-
lated thyroid doses inthe Mtarshallese were con:
sidered to be below the levels ikely to produce
humors, Fadditon, neither the iapartince of the
exposure to short-lived todine ieatopes ta fallous
nor the divroid dose ciilerential in children due to
the smaller size of their ghind wis fully appreciated,
Tas quite likely thatthe Gaal cesulis of thyroid
lesions inthe Marshallese are dacomiptere at this
lime since new desions are sail occurring. “The
.
"
htt,
inean latent period for radiation-induced thyroid
tumors may be as long as 30 years. Cases have
becn scen as late as 40 years after exposure. Furthermore, on the basis of the present data the risk
of developing radiation-induced thyroid neoplasia
is probably underestimated, since surgical removal
of potentially malignant tissues may have occurred
and the hormone treatment mayhave inhibited
the development of some tumors, although the latter is questionable, As has been pointed out, also,
the true carcinogenic potential of the exposure,
particularly in the children receiving the higher
duse, may have been masked byexcessive cellular
destruction. The recent finding that subclinical
thyraid deficiency is present in sume of the ex-
posed people who have not shown anythyroid abnormalities indicates that the thyroid effects in the
Marshallese may nat vet be completely manifest,
and continued careful surveillance of this populalon Is necessary.
Acknowledgments
Because of the broad scape of the surveys and
the complexity of operations it would be impossible to acknowledge all the individuals and organ-
ations that have contributed to the success of the
surveys over the past 20 sears. We would fike,
however, to express thanks to some who have contributed vitally in more recent vears.
Our foremost appreciation is to the people of
Rongelap and Utirik who have participated in the
cxaninations, including the unexposed people
comprising the control population, We treasure
the friendship and trust of these people. We are
grateful ta many Rongelap and Ciirik people for
assisting: the examining teams over the vears, inchiding the Magistrates of both istands - a1 Ronvelap: John Anjain, Billicr Kdmond. fabwe Jorju.
and Nikunmos Antak: at Girik: KRabto Campus,
Maja Lena, Harold. the school principal. and
Joata. the health aide.
‘Phe senior author is most grateful to the many
fine medical anc other specialists (listed in Appendix 2) who have so willingly given of their time
and talents, without remuneration, to participate
in the surveys. Without their dedicated efforts the
surveys could never have succeeded. Fle is also
greatly indebted to the many technical assistants
who have conmibuted nnueh to the success of the
surveys, particuaily to Mr. W. Seott and Mr 1D.