Re: Potassium iodide, continued

[PAMS718@aol.com]

In my original  response to Mr. Crane's posting about KI use in Poland after the Chernobyl accident  and the lack of thyroid cancers in Poland, I suggested that it was because there wasn't enough iodine in Poland to cause thyroid cancers.  In his  response, Mr. Crane suggested to me two references,(with which  I was very familiar and in fact, had based my statements on) which he believed showed evidence to the contrary.  This is a good example of the lousy job that we, in the health physics field, are doing in communicating to laypersons the terminology and numbers we use to quantify such things as dose and activity and carcinogenesis.   

Mr. Crane references Nauman & Wolff's paper, "Iodide Prophylaxis in Poland After the Chernobyl Reactor Accident: Benefits and Risks"  In this article , the authors quote maximal environmental  contamination levels and prophylactic  intervention levels in childrens'''   thyroids.  As stated in the article, the maximal contamination level, which occurred during the April 28 to May 13 1986 time frame was 253,000 Bq/kg of vegetables.  Oh my, 253,000 of anything sounds very scary and indeed, thyroid threatening, if not life threatening.  But what value does that really translate to?  If we do the math and translate that to "American units" we see that this very scary value is 6.8 microcuries of activity in 2.2 pounds of vegetables.  Is that a lot? Well, of course, you wouldn't want your children to consume 6 microcuries of iodines regularly, (do kids even eat 2.2 pounds of vegetables?) but will it give them thyroid cancer?  The maximal value for milk (April 28-May 13)  was 2,000 Bq!
/L or about 5.4E-5 uci/ml; the 10CFR20 appendix B Table 2, col 2 effluent water concentrations for I-131 is 1E-6 uci/ml.   The Polish authorities promptly interdicted milk and food suplies when measured child thyroid values were about 500 Bq to 1300 Bq.  The food supplies remained restricted until the environmental values returned to more normal levels.  And only single doses of KI, which has a finite lifetime in the thyroid were administered.    The maximal value for air contamination was 571 Bq/m3 or about 1.5E-8 uci/cc, more than the US effluent release limit of 2E-10 uci/cc (10CFR20 Appendix B Table 2 col 1) and almost the same as  the US occupational exposure limit, 2E-8 uci/cc (10 CFR20 Appendix B table 1 col 3).  

The interdiction level used by Polish authorities for childrens' thyroid was 5700 Bq... again a large and scary number...or is it?  5700 Bq is 0.15 uci.    The US occupational exposure level is 5000 millirem per year.  The public is limited to 100 millirem per year..a factor of 50 less.  The occupational ALI for thyroid is 50 microcuries, which will deliver 50 rem committed effective dose to the thyroid.  If we apply that same 50 fold reduction, then the limit for the general public  would be 1 microcurie or about 1 rem committed effective dose to the thyroid.     Indeed, in the US emergency planning dose levels were based, for years, on 5 rem to child's thyroid, now planning standards are 5 rem CEDE to the thyroid.   The highest Thyroid I-131 content in a child in Poland was found to be 14,098 Bq, .about 0.38 microcuries. 

I am not opposed to saving lives and I am not in favor of exposing our children unnecessarily to hazards.    In a perfect world, these wouldn't even be questions.  But, we don't live in a perfect world.  My concern, as I said before and I will say again: in this country, the United States, does it make sense to take resources away from a limited pool to protect against a very, very, very small risk of accident and hypothetical, calculated increases in cancer?  Doesn't it make more sense to take that same money and save real lives?  Lets fix the deadly traffic intersections, lets get rid of the E-coli contamination of foods that is killing our children, real lives..not hypothetical what if's...  or we could  make everyone's house as safe as nuclear power plants... and then we would save about 15,000 real lives per year.  

In the worst commercial nuclear power plant accident in the United States, ( with nukes in operation for 30+ years)  only 15 curies of radioactive iodines were released.  No one has died in the United States from commercial nuclear power plant accidents.  There are no cancer clusters surrounding nuclear power plants.  Not even after the TMI accident.   

I would refer Radsafers to an interesting article  submitted to Nukleonika, October 1997 by Dr. Zbigniew Jaworoski, MD, PHD, Dsc, professor emeritus from the Central Laboratory for Radiological Protection in Warsaw, chairman of the United Nations Committee on the Effects of Atomic Radiation.  In this article, Dr. Jaworoski suggests that "the lack of increase of registerd thyroid cancers in Poland however, was probably caused by a more important factor rather of a poltical than radiological nature.  Opposite to Belarus, Ukraine and Russia, neither eastern nor any other parts of Poland were declared "contaminated" and there were no economic or psychological motivations for an increased awareness by parents and medical staff, and for a change in the number and quality of medical examinations.  If such motivations appear, than one could expect a multifold increase in registration of thyroid cancers in Poland, or in any other country....This is due to a very high number of "occult"!
 thyroid cancers, without clinical manifestation, which occur in "normal populations" (Fransilla &Harach 1986, Harach et al 1985).  In "normal" populations the incidence of clinically diagnosed thyroid cancers ranges from less than 0.5 per 100,000 persons in the USA and Central Europe to 8 per 100,000 in Chinese and Filipinos living in Hawaii... The occult thyroid cancers, which are detected at autopsies by histological studies, occur in normal populations with a thousands times higher incidence, which ranges from 5600 per 100,000 i Columbia to 35,000 per 100,000 in Finland.  In the younger age group (0-15 years) th incidence of occult cancers in Finland is lower (2,400 per 100,000).  The occult cancers are of the same paillary type as those found in Belarus, and show an invasive growth pattern (Fransilla&Harach 1986).  Thus the potential for detection of "excess" thyroid cancers, after improving or intensifying the diagnostics, is enormous and could lead to an even greater in!
cidence than in the highly contaminated region of Gomel in Belarus, where the incidence of 11.3 per 100,000 children was reported as caused by Chernobyl radiation.... As may be seen in Figure 4, during the most active period of screening in 1974 to 1979, the incidence rate of malignant and all thyroid nodules was greater 21-fold than before 1974.  This increase is of the order of that seen in Belarus (Ron et al 1992).  The increased number of thyroid cancers registered in the former USSR may be an effect of intensificaiton and improvement of diagnostics, rather than a real effect of radiation"

I am not suggesting that European countries are wrong for  their use of KI.  Their situations are entirely different than ours.  I am only suggesting that, for the United States, implementation of KI just isn't a good use of resources.
                            Patricia M. Sullivan, CHP
            

Two recent postings to RADSAFE dealt in whole or in part with the NRC's
proposed rule on KI (the "fighter jet" rule).  They came from the NRC's
Patricia Sullivan (PAMS718) and Dr. Carol Marcus.  I'd like to respond
briefly to both.

Ms. Sullivan's thoughtful posting raises a number of issues.  She
suggests that KI cannot have been effective in Poland because
administration did not begin until 2 to 4 days after the accident, and
KI, to be effective, must be administered just before, during, or just
after the release.  I would answer that the usefulness of KI depends not
on when the radioactive release occurs, but when the radioactive iodine
is inhaled or ingested.  It took some time for the winds to bring
radioactivity to other parts of Europe; moreover, it came not in a
single release, but over a period of days.  Thus the notion that Polish
children received KI too late to derive any benefit is not, I think,
correct.

I do not take issue with the proposition that ingestion, especially of
milk, was the principal source of children's exposure to radioiodines
after Chernobyl.  (Ms. Sullivan writes that in the former Soviet Union,
"It is believed that the increases in thyroid cancer can be attributed
mostly to ingestion.")  "Mostly" is not the same as "exclusively,"
however.  If it is conceded that inhalation was responsible for some of
the post-Chernobyl cancers, then it is worth asking whether it is worth
spending a small amount of money to achieve an additional level of
protection against inhaled radioiodines.  

As far as the claim that not enough radioiodine reached Poland to have
caused any thyroid cancer, I can say only that Dr. Janusz Naumann, the
distinguished Polish physician and teacher who directed his country's
administration of KI, takes issue with it.  She might wish to contact
either Dr. Nauman or Dr. Jan Wolff, of NIH, who with Dr. Naumann
co-authored a paper in an American medical journal on the Polish
experience with KI.  She and other RADSAFERS might usefully consult
"Radiation and Thyroid Cancer," a book published earlier this year.  It
consists of papers delivered at the 1998 Cambridge University conference
of that name.  The conference was co-sponsored by the European
Commission, the U.S. Department of Energy, the National Cancer
Institute, and Cambridge University.

Ms. Sullivan is correct in saying that U.S. policy emphasizes evacuation
and interdiction of food supplies.  But evacuation is not always
feasible, and even when it is, people can be irradiated while
evacuating, as EPA stressed in a 1992 report.  It's worth noting that
back in the years when nuclear power plants were being licensed,
opponents of plants would often argue that a particular site could not
be evacuated in the event of an accident that tied up roads or in bad
weather conditions, or the like.  In response, the NRC at that time took
the position that evacuation was not necessarily the be-all and end-all,
and that in some situations, sheltering would be preferable.  (The 1992
EPA report also said that there would be situations in which sheltering
is preferable.)  The current guidance, stating that evacuation is
invariably the best approach, was not issued until 1996, the year after
I filed my petition for rulemaking on KI.  I continue to believe that
there may be situations in which sheltering is the option of choice --
if only because other options don't exist -- and that in those
situations, the availability of KI could improve protection and could
not impair it.

It did not occur to me, until I read Ms. Sullivan's posting, that anyone
would take my reference to my own experience with thyroid cancer as
suggesting that KI could have prevented my illness.  That wasn't my
intention at all, and I apologize if what I wrote was unclear.  I was
trying to make the point that my own experience of thyroid cancer leads
me to believe that (1) it is an illness well worth preventing, and (2)
to the extent that current U.S. policy is grounded on the notion that
the illnesses that KI can prevent are inconsequential, that policy is
seriously flawed.  Anyone who reads the transcript of the public meeting
on KI that the NRC held on November 22, 1983, will find that the NRC
staff represented the effects of radiation-caused thyroid disease in the
mildest terms:  never using the word "cancer," never mentioning a
lifetime on medication, never referring to possible fatalities, but
instead referring to a "relatively minor operation" involving "a few
days loss."  

To Ms. Sullivan's point that some states have already implemented KI
stockpiling, without being required to do so by the federal government,
that's true.  (They are Tennessee, Alabama, Arizona, and Maine).  But in
the case of Maine (and also Ohio, which is in the process of moving to
stockpile KI), the state decision to stockpile has come not because of
the information provided by the NRC, but in spite of it.  I was at the
meeting in Maine in 1996 in which the state's advisory committee
recommended unanimously in favor of stockpiling KI, and it is fair to
say that they were not happy at the contrast between what the NRC had
been telling them and what their own research turned up.  At this point,
after so many years of inaccurate and inadequate information provided to
the states and the public by NRC, a rule change seems to me the only
reasonably sure way of rectifying the problem.  

Dr. Marcus's posting can be dealt with briefly.  I wish she had been at
the Cambridge conference to offer her novel suggestion that the
post-Chernobyl thyroid cancers were caused by KI, rather than by
radioactive iodines.  I wonder what "we" she had in mind when she wrote,
"We don't know why young children near Chernobyl developed thyroid
cancer...."  The doctors and scientists who are the world's foremost
experts on radiation and thyroid cancer were at Cambridge, and they did
not seem to be in the dark on that point.  I suggest that she consult
their published articles.

Dr. Marcus seems to be suggesting that I-131 does not cause thyroid
cancer, based upon the releases from Hanford and persons receiving
radioiodine for medical reasons.  The director of the Hanford study, Dr.
Tom Hamilton, recently told a meeting of the NRC's KI Core Group that he
himself would "gobble KI" in the event of a nuclear accident.  Clearly
he does not put the interpretation on the Hanford data that Dr. Marcus
does.  Regarding medical uses of radioiodine, the argument has been made
by my old friend and colleague, Dr. Myron Pollycove of the NRC, that a
long-term study by Dr. L.-E. Holm of the Swedish Radiation Protection
Institute (finding no increase in thyroid cancer among patients treated
with I-131 for Graves' disease) proves that I-131 is not carcinogenic,
and that KI is therefore unnecessary.  Dr. Holm spoke at Cambridge, and
afterwards took questions from the floor.  I mentioned the argument just
described, and asked him to comment.  He replied that he was aware that
this argument was being made, that it was a misinterpretation of the
results of his study, and that he himself favored stockpiling of KI.

I hope that European experts, with direct experience of Chernobyl and
its consequences, will contribute their thoughts to this discussion.

Peter Crane
pgcrane@erols.com 
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