ORRHES Meeting Minutes,
June 11-12, 2001
June 11, 2001
The Agency for Toxic Substances and Disease Registry (ATSDR)
and the Centers for Disease Control and Prevention (CDC)
convened the fourth meeting of the Oak Ridge Reservation
Health Effects Subcommittee (ORRHES) on June 11-12, 2001.
The meeting, which was held at the Oak Ridge Mall in Oak
Ridge, Tennessee, was begun by Chair Dr. Kowetha Davidson
at 12:32 p.m.
Members present were:
Alfred A. Brooks
Robert Craig
Kowetha A. Davidson, Chair
Robert Eklund
Edward L. Frome
Karen H. Galloway
Jeffrey P. Hill
David H. Johnson
Susan A. Kaplan
Jerry Kuhaida
James F. Lewis
Lowell Malmquist
L.C. Manley
Therese McNally
Donna Mims Mosby
William Pardue
Barbara Sonnenburg
Members Mr. Don Creasia, as was Mr. Charles Washington
on June 11. The resignation of Dr. Ron Lands was regretfully
announced, due to a change in his practice and schedule.
Ms. La Freta Dalton, Designated Federal Official (DFO)
and Executive Secretary of the Subcommittee, was present.
All the liaisons to the Subcommittee attended:
Elmer Warren Akin, U.S. Environmental Protection Agency
(EPA)
Brenda Vowell, R.N.C., Tennessee Department of Health
Chudi Nwangwa, Tennessee Department of Environmental Conservation
(TDEC)
Agency staff present were:
ATSDR: Bert Cooper; William Carter, Greg Christenson,
La Freta Dalton; Michael Grayson, Jack Hanley; Karl Markiewicz;
Bill Murray; Therese NeSmith; Marilyn Palmer, Jerry Pereira.
DOE/Oak Ridge Reservation: Timothy Joseph
Tennessee Department of Health, Office of Minority Health:
Robbie Jackman
Others present over the course of the meeting included:
David Hackett
Owen Hoffman, SENES
Bill Moore, Tennessee State Epidemiologist
Norman Mulvenon, LOC/CAP
Dwight Napp, Save Our Cumberland Mountains
Grace Paranzino, MCP MCP Hahnemann University
Robert Peelle
Debbie West, court reporter
Opening
Comments
Dr. Davidson welcome the attenders and thanked the Department
of Energy for the tour of the ORNL facility provided that
morning. The Subcommittee members briefly stopped by the
graphite reactor, site of lithium separations process and
the smoke stack associated with the those releases; the
area of the underground Gunite tanks now being cleaned,
the intersection of White Oak Creek and the Clinch River;
the Solid Waste Storage Area #4; the molten salt reactor,
and the cesium plots. Dr. Davidson also reported a meeting
of the Work Group Chairs, and their discussion of the COSMOS
recommendations presented at the last meeting. Designated
Federal Official Ms. Lafreta Dalton also welcome everyone
to the ORRHES meeting.
Dr. Davidson reviewed the agenda and drew the members'
attention to inclusions in the meeting materials: a glossary
of terms from ATSDR and the final draft of ORRHES Bylaws.
No comments were voiced about the minutes of the March 2001
meeting, which were approved. Most of the action items listed
therein had been accomplished. The minutes from April 24th
conference call were also approved.
Presentation
of the ATSDR Division of Health Education and Promotion
Dr. Greg Christenson, Acting Director of the Division of
Health Education and Promotion, discussed some of the issues
addressed by the Division and its work at the Oak Ridge
site. The Search Committee for a permanent Director developed
a list of candidates for ATSDR Assistant Administrator Dr.
Henry Falk. They will be interviewed between July 5-20,
after which a new Director may be named. Dr. Christenson
is not a candidate. He noted the importance of continuity
to this community, and reassured the Subcommittee members
that ATSDR's activities at Oak Ridge are part of the Division's
core program, and will be done. The establishment of the
ATSDR office in Oak Ridge is just one indication of that
commitment.
Dr. Christenson provided an overview of the Division. Its
has three Branches:
-
The Risk Communication and Research Branch conducts
case studies in environmental medicine that update physicians
on the latest science and its clinical applications.
About 33 case studies are complete now, and 4-5 are
in development. For example, a current study in development
is on iodine-131 (I-131), which should be available
to be part of the George Washington University (GWU)/MCP
Hahnemann University-developed Provider Education Program
at Oak Ridge. Most are topical, focusing on a specific
toxin or chemical, but others are more general, such
as one for physicians on how to take an environmental
history and another on the application of environmental
health to the pediatric field.
-
The Health Education Branch, in which Ms. NeSmith works,
develops strategies, models, and materials for educating
populations in general as well as physician and provider
education materials. These two Branches work together
in a process to allow outreach to community members
and providers to provide the information that they need.
-
The Health Promotion Branch conducts environmental
health intervention programs, including the needs assessment
being done at Oak Ridge by GWU. That is expected to
result in a work plan to direct future activities to
help this community, and help ATSDR's other Divisions
to support those activities. Oak Ridge has the potential
of using many ATSDR resources. Those processes are beginning,
but as often happens, things seems to take a little
longer than expected.
Discussion included:
-
Mr. Lewis: What are the various components of the
work plan, and how does it interact with the needs assessment?
This is a health education work plan that will be developed
from the analysis of the needs assessment's information,
derived from the telephone survey, focus groups, and
key informant information. Using that information, educational
strategies will be designed to intervene to provide
the necessary information for the special needs of subgroups
or the population in general. The basic work plan will
evolve from the health education requirements and the
needs assessment, and the basic science done by the
Division of Health Care Assessment and Consultation
in developing of the health assessment.
-
Dr. Brooks: Can you provide information useful
to develop a program of work to address contaminants
of concern, and a loose timetable for the ORRHES meetings
at which these will be discussed, for the Health Needs
Assessment? We can developed a time line for the
needs assessment's conduct and analysis, in general,
but some things cannot be controlled (e.g., other people's
schedules, and Institutional Review Board [IRB] approvals).
Dr. Brooks expressed the Subcommittee's understanding
that this would be a living document with likely slippage,
and agreed to provide the style developed in order to
have such a guidance document ready for the next committee
meeting. This is not ATSDR's longer program of work
document, just a brief 1-2 pager to identify the tasks
on a time line.
-
Dr. Malmquist: Can you assure us that this health
needs assessment will focus on the environmental impact
from the reservation upon the general population?
The ATSDR is not looking for general chronic health
problems such as cardiovascular disease, but for health
issues related to potential environmental hazards in
the community
-
Dr. Brooks: This community distinguishes between
environment hazards related to the Oak Ridge Reservation
(ORR) and environmental hazards in general. Dr.
Paranzino will most likely address issues of general
concern environmentally and specifically target those
that this community would focus on.
-
Mr. Lewis: In releasing messages, the major components
of developing the work plan of the assessment process
should be explained in a little more detail in layman's
terms; and what will be the components of that educational
piece, to community, physicians; using television?
All the necessary information will be released on a
fact sheet which should be ready relatively soon. But
the information transfer process is complicated, requiring
not only physician but also community training, so the
latter can ask and respond to appropriate questions
with their health care provider. Education for both
groups will be pursued. The environmental health care
intervention program will involve on-the-job training
for local practitioners in which clinically experienced,
environmental health experts share in seeing their patients
who may have diseases related to environmental issues.
This paradigm has been demonstrably successful in chronic
disease (e.g., breast or cervical cancer screenings)
and are hoped to be similarly helpful for environmental
health applications.
-
Mr. Lewis: What is our status as a Subcommittee
relative to some of ATSDR's other sites? Several
sites are experiencing this strategy of community and
health care provider education, so determination of
the program's effectiveness is still pending. At least
anecdotally, linking educators and communities in implementing
this strategy is an effective method, even in the environment
health area.
-
Dr. Brooks: How will ATSDR address the problem
left in the community, if the study cannot prove that
the health concerns they believe are ORR-associated?
That is a complicated issue. Historically, it
may well be that the health assessment will find association
between ORR contaminants and the city of Oak Ridge's
health problems. Education can not do everything, but
it might be able to reduce the stress level and help
provide more realism about what the potential conclusions
may be. A federal agency can only do so much, and is
limited in its ability in a short period of time to
address the community's long-developing perception of
effects may have resulted from the reservation's work.
Some members of the community will not be satisfied
with how ATSDR addresses that. But the best it can do
is to provide the most accurate, most reflective response
to the information gathered, to help the community at
least understand what science knows and does not know
at this point in time.
- Dr. Brooks: Will you stick around for a little
while and help us allay these fears, not forever, but
long enough for a reasonable effort to convey the findings
through the community? ATSDR is committed to stay
at the site to do the health assessment and what is necessary
to explain its results, and to be certain the processes
are all completed. This as a priority site. ATSDR will
remain as long as a reasonable contribution is being made.
Update
of the Health Needs Assessment
Dr. Grace Paranzino, of MCP Hahnemann University, updated
the Subcommittee on the status of the Health Needs Assessment
being conducted by George Washington University (GWU) and
Hahnemann. They revised some of the survey tools after the
last IRB meeting, which will remain in draft format pending
feedback from the Subcommittee, after which they will be
resubmitted for the IRBs' approval. The latter are necessary
to ensure that the study is ethically conducted, scientifically
founded, and properly budget. The Tennessee Department of
Health also has asked to see them. Work remaining includes
the key resource interviews, telephone survey, focus groups,
and final report. The questionnaire format has been completed,
and is in review by the various IRBs.
The key resource interviews will begin in mid-June
and be completed some time in July. The geographic areas
to be sampled by the telephone survey was narrowed with
the Subcommittee's help; the exchanges to be called were
identified, and random numbers in each will be called in
August. The survey question draft is completed. About 400
people will be surveyed, which may well require ~1200 calls.
The initial screening questions will help identify those
willing to participate. GWU/MCP Hahnemann will submit any
final suggestions from the key resource interviews back
to the working group for approval and then modify the survey
as needed. The focus groups, defined with the input
of the key resource interviews and the telephone surveys,
will be held in September. They will involve the different
subsets of the population that have issues of concern and
focus on the health effects and health education needs related
to the ORR, along with a few general questions.
The target date to complete the Health Needs Assessment
is the end of December. The final report will forwarded
through the Work Group to the Subcommittee and ATSDR for
comments, revisions and modifications as needed.
Discussion included:
-
Dr. Brooks: Please translate your time to line
to the Subcommittee meeting dates at which these things
will be reported. And, will you screen the effects of
the environment pollutants from the Kingston and Bull
Run power plants, whose interaction with the ORR pollution
concerns many people? If they are conceived as
being a part of the overall ORR picture, GWU/Hahnemanns
would need to separate that out.
-
Dr. Brooks: Is your "work plan" part of the ATSDR
plan? Yes, the health education action plan is
to define what people want to know more about regarding
health education, to identify the forces involved (i.e.,
resources that will facilitate the process or that need
to be developed); and how to get that information out
the community and health care providers, including alternative
strategies if limited resources require them.
-
Dr. Brooks: Does the action plan derive solely
from the health needs assessment, or is there input
from the health assessment? Dr. Christenson answered,
both; it will be a joint effort by the Division of Health
Assessment and Consultation and the Division of Health
Education and Promotion.
-
Dr. Davidson: Is the health education action plan
part of the December report? Yes.
-
Mr. Lewis: Will there be one or two sets of questions
in the screening process, one to screen people out and
another of detailed questions? Sharing the screening
questions would help alleviate concerns about what is
being targeted. GWU/MCP Hahnemann have no problems
sharing the general theme of the questions and how they
will be asked, but they cannot be a public document
for fear of biasing the process.
-
Mr. Lewis: What were your opinions/conclusions
from the documents reviewed, and how will they be used?
For example, from where did such reports as the one
on community diagnoses originate? How will they be used?
Many surveys have been done of the ORR area, all of
value in some way. GWU/Hahnemann's role is not to critique
them, but just to see what they offered that might benefit
this work. Some of that work's methodology was similar
(e.g., focus groups and telephone surveys), but most
of those focused on general parameters or general indicators
of health in Oak Ridge and surrounding communities,
as opposed to this project's tailoring it to be more
specific to the ORR.
- Mr. Akin: How will ATSDR respond to the comments
on the December draft report? Could they initiate more
work? It depends on the comments. The responses
would not necessarily be individual; GWU/Hahnemann would
respond to the comments and direct them either to the
Work Group, the Subcommittee, or ATSDR. If the comment
defines a limitation that cannot be corrected, that is
acknowledged; more research could be a Subcommittee recommendation
to ATSDR.
Public
Comment
Mr. David Hackett is a local professional engineer
in private practice. Confusing this Subcommittee with the
ORHASP, he stated that ten years of this committee's work
and dose reconstruction had produced far too little. He
respected Dr. Hoffman's attempt better understand "the mess
here in Oak Ridge," but in his opinion, rather than science,
the work done here has been a smoke screen to confuse the
public. Aside from I-131, the public has not been reassured
that they have not been exposed to carcinogenic levels of
uranium, fluorine, nickel, arsenic, mercury, chromium, neptunium,
plutonium, or beryllium. He called the work done to date
pseudo science done with randomly selected exposure standards
and falsified reported data. He was convinced that it was
a malicious ruse by the government to convince the community
it has been protected all along. Oak Ridge knows better.
He condemned "the scoundrels whose ... opinions are for
sale to the highest bidder" to protect actions of the past
and termed the I-131 study "trash." He called for closer
scrutiny of where the data originated from. In his opinion,
what Oak Ridge needs and has asked for is a health study
to show the exposures have been, and health care for those
already sick and dying. He cited increased local cancer
rates and the disruption of many area residents' immune
systems. He asked rhetorically, If it is so safe, why millions
are needed to clean up the environment. He charged that
exposure standards treat exposed humans as canaries were
in the mines. The human response is such that on the bell
curve, only a few sensitive individuals will be harmed (the
canaries). It took two million "canaries" getting sick to
lower the standards. He called for an end to cover-ups of
toxic exposures and real study of the health effects of
low doses that display no overt symptoms for years but continuously
undermine the immune and central nervous systems. He felt
that any decent scientists with expertise will willing acknowledge
how much they don't know as well as what they do, and those
who speak knowingly and confidently "... are certainly full
of (manure.)"
Dr. Davidson requested that the public commenters remember
the codes of conduct for the meeting and asked Mr. Hackett
to provide his written comments.
Ms. Janice Stokes thanked the members for their
service. While she respected the members, she had more of
a problem with the past actions of ATSDR, CDC, and DOE,
the source of much of the anger heard, regarding their scientific
methods and the truthfulness of the documents used. She
urged the panel to not accept everything provided by ATSDR
as acceptable science. She also requested that public comment
be allowed in the presentations by Dr. Hoffman, Dr. Widner,
and Mr. Hanley, as well as throughout the meeting, so that
the public who cannot wait to the specified comment periods
have an opportunity to speak and ask questions on the record.
Such a procedure would allow the full history of events
to come out.
Dr. Davidson responded that that format had been considered,
but the Subcommittee wished to avoid losing the time for
full presentations and preserving time for questions. The
entire agenda could be disrupted by getting caught up in
questions during the presentations. In addition, four presenters
were scheduled over four hours to allow time for questions.
If they speak for less time, discussion is possible. Ms.
Stokes asked why the Subcommittee even bothers to have the
public come, if such a controlled environment is desired,
and noted that there is no affected citizen on the panel.
Task
One Report, Tennessee Oak Ridge Dose Reconstruction Study
The State of Tennessee's Oak Ridge Studies, July 19, 1999,
Task One Report, was presented and discussed, focusing on
the technical issues of the dose calculation, risk estimates,
probability of causation, excess cancer, and thyroid cancer
analysis. The discussants were Dr. Tom Widner, of JA Jones
Environmental Services; Dr. Bob Peelle of the ORHASP; Dr.
Owen Hoffman, of SENES Oak Ridge; and Dr. Michael Grayson
of ASTDR.
Mr. Jerry Pereira of ATSDR noted the unlikelihood that
anyone's opinion would be changed by these presentations
on this day. He commented that the purpose for this panel
was for the Subcommittee to collectively listen, learn,
and perhaps make some personal judgments; and then to proceed
with it work. He hoped that listening from that viewpoint
would everyone to have a better perspective on the information.
ORHASP
Perspective.
Dr. Robert Peelle began with the study's background. The
State of Tennessee commissioned a study of potential offsite
health effects from the ORR, which DOE agreed to fund and
which began in 1974. One of the priority contaminants determined
by a feasibility study was radioiodine from the Radioactive
Lanthanum (RaLa) process. The ORHASP Committee was reorganized
during this project. The ORHASP was a committee of citizens
and experts, which monitored the progress of the study and
interacted with the interested public who attended their
meetings. Their activity ranged between active oversight
and passive review.
The panel had no interest in judging the DOE or the Atomic
Energy Commission (AEC), but only to determine the facts.
They pushed for a serious records search to explore anything
related to potentially hazardous off-site releases. Over
time, the DOE policies changed and they cooperated in searching
for records. The panel also strove to produce unbiased risk
estimates and to be respectful of the public's concerns.
They explicitly considered the variability of the individuals
affected (age, weight, size of thyroid gland, etc.) by approximating
the variables' distribution of density, function, and frequency
in the population. They then combined all the data available
in a Monte Carlo analysis to determine the 95% confidence
level. That is, the actual truth could be 5% higher or a
little lower, lying within the ends of a confidence interval.
The confidence limits were so defined because there is
no evidence that the median value is either the real or
the best answer. This is because many of the parameters
in the analysis offer little data, and because it is not
certain that the best value was estimated. Finally, the
panel assumed that the doses had no threshold for excess
cancer risk. They addressed what appeared to be the most
important pathways of contamination, and set the lesser
ones aside for later study.
JA
Jones Perspective.
Dr. Tom Widner, who was the Project Director of the work
described by Dr. Peelle, provided more detail. The initial
feasibility study reviewed Oak Ridge work from the beginning
of the site's operations, and identified four materials
of concern. The dose reconstruction explored those, fed
by a systematic document search. The final deliverables
of the Oak Ridge dose reconstruction were the draft and
final task reports, a nine volume set; the ORHASP report;
and a project summary which briefly covered the whole project
and offered sample exposure scenarios to demonstrate how
people could have been exposed to multiple contaminants
over time. The Tennessee Department of Health Website has
extensive information (he also brought hard copies to this
meeting), and many of the source documents will soon be
available on the Internet.
Dr. Widner focused on the RaLa process, which resulted
from Dr. Robert Oppenheimer's request for it to help Los
Alamos' early weapons explosion design testing. The source
material for this radioactive lanthanum was radioactive
barium 140, which was made in Clinton, in the Oak Ridge
area. At Los Alamos, a round sphere containing the lanthanum
was exploded; the lanthanum's very high gamma rays were
used to measure the timing and uniformity of the implosion.
RaLa Process: The RaLa processing was the dominant
iodine source due to its short cooling time and the large
number of barium slugs processed. Natural uranium was placed
into a reactor and divided into fission products, including
barium, which decayed to the lanthanum 140 desired by Los
Alamos. In the RaLa processing building, those fuel solutions
were quickly dissolved in nitric acid (due to barium's short
half-life). This process also released other fission projects
such as I-131. The iodine-to-pasture pathway was still unknown
at that time, and little environmental or process sampling
for iodine was done.
Lanthanum processing emission points included: 1) the caustic
scrubber, which was designed to reduce the acid vapor emissions,
but may not have reduced the iodine as well, and 2) the
processing equipment itself, which was used well beyond
its design capacity. Designed to make 1000 curie batches
of barium, they instead made up to 65,000 curie batches
without upgrading the equipment.
The study screened out I-133 as a contaminant of concern
when it was found to not have elevated the ingestion pathways.
That was supported by a systematic document search of ~40
record repositories and interviews of current and former
workers. The Clinton processing lines were prioritized because
they involved large amounts of nuclear fuel with relatively
short decay times, or had well-documented instances of off-site
contamination before the off-gas treatment systems were
perfected at Oak Ridge.
The source term is the quantity released, its
timing, and the forms of the release. The records provided
a chronology of ~80 RaLa batches. The study calculated how
much iodine was within each of the fuel slugs. Some decay
occurred between the 2-14 hours between removal from the
reactor and its placement in the dissolver, but the slugs
from Hanford took 5-6 days to transport. Original operations
and health physics logbooks enabled classification of each
dissolving batch, based on how likely its releases were
to have bypassed the caustic scrubber. In some cases, the
leaks were so strong that the operators had to wear respirators
to complete the run.
The RaLa process was unpredictable. To compensate for the
lack of monitoring, the study estimated iodine behavior
in the system in several ways: expert opinion, modeling
of the process, and the experience of other sites. The iodine
species in the dissolver was thought to be either elemental,
organic, or particulate iodine form. They estimated the
mixture of iodine isotopes in the dissolver, how much was
released to the gas removed from the dissolver to the scrubber
and the stack, and how much was left on the scrubber. Dr.
Widner outlined some the expertise of those who were consulted.
There were virtually no measurements of the iodine species
in the dissolver, but they estimated it to be 94-99% elemental
and fractional amounts of volatile organic, non-volatile,
and particulate forms. Oak Ridge did not use any organic
reagents in the process, so only trace organic iodine was
thought to be present. The scrubbers were supposed to be
99% efficient in capturing the elemental iodine and 1-10%
efficient for the volatile organic and particulate forms.
A scrubber model that was developed estimated 99% capture
efficiencies for the scrubber when the caustic solution
was used. When water was used instead, the efficiency was
lower by a factor of ten.
However, the study experts consulted thought those collection
efficiencies to be overestimates. Based on Oak Ridge monitoring
studies and scrubber experience at other sites, and a RaLa
monitoring study done at one point in time over the 13 years,
they concluded a 90-99% efficiency for elemental iodine
and 50-99% when water was in the scrubber. Particulate releases
were estimated from processing stack sampling data.
Modeling of the elemental iodine releases estimated a line
loss of 20-70%. The well-documented line problems prompted
the study to increase the line loss factor. The elemental,
organic, and particulate releases were summarized. The modern-day
annual intake limit is .0005 curies. Much higher releases
were documented in 1954 during an uncontrolled release that
lasted from one-half to four hours. However, these releases
ended up to be a very small fraction of the routine releases
(280 of 21,000 curies normally released).
Elemental iodine can break down the presence of sunlight
to form other forms of iodine; organic iodine does so at
a much slower rate. So, the most important chemical transformation
would be from elemental to organic iodine, a transformation
the dispersion model took into account. However, organic
or particulate iodine remains in those forms while traveling
to the receptor. Depletion or reduction could occur during
wet deposition (washed out of clouds by rain and dew). Dry
deposition was also modeled with what meteorological data
were available. Some hourly data could be analyzed as well
to develop a statistical set of probability distributions
for each month and each hour of the day by wind speed, direction,
and atmospheric stability.
Deposition is a parameter that describes the iodine's
rate of transfer from the air to the surface of ground or
vegetation. The ratio of the air concentration to the deposition
flux, to the ground or to the plants, is called velocity
of deposition. There was good such data for the time of
the 1954 accident, which was modeled for the 38 kilometers
around the X-10 central stack. That area was divided into
sixteen directional segments or sectors, with about 25 distances
in each direction, in a dispersion grid.
The air dispersion model was validated with monitoring
data available from 1967 to 1969 at nine sampling stations
near or on the reservation, which were compared using the
ISC and IAC models. The study's model results were within
a factor of two of the observations, and the other models
were within a factor of three. That indicated the model's
adequacy for estimating routine releases of iodine from
X-10.
To estimate short-term releases, health physics reports
of specific iodine curies released were compared to the
modeling results. For two episodes, the model prediction
and actual measurements were within the 95% confidence interval;
the model under-predicted other episode. Appendix 11 of
the study report provides the dispersion model's detailed
concentration estimates for the study domain and the estimated
concentrations in the other environmental media.
Vegetation deposition is important for iodine.
The literature provided parameters with which to estimate
the behavior of iodine released on vegetation, and there
were some field measurements of deposition velocity. Those,
with available rain data, produced deposition distributions
over time, correlating precipitation data to the routine
releases. The transfer from pasture to food/milk was then
calculated. Some validation of predictions of iodine concentration
in milk were done with milk measurements from 1962-64, compared
to the monitoring stations' measurements. Almost universally,
the average measured concentrations were in the predicted
95% confidence level.
Distribution of food products was accounted for
(time lapse of milk/food processing to delivery) in the
reduction of iodine concentration in the consumer, based
on literature reviews and interviews. Food intake by humans
was estimated for different age groups and genders, and
for inhalation. Internal dosimetry is enabled by standard
calculated dose coefficients to the thyroid gland for a
given intake of I-137. The mass of the thyroid gland was
a key parameter in calculating the dose to the thyroid.
The smaller the mass, as in children, the higher was the
energy deposited per unit mass and the dose. The dose factors
were also recalculated in uncertainty analysis to try to
determine which parameters of the dose calculations most
contributed to the overall uncertainty of results. Ultimately,
the data indicated that the smaller thyroid mass was offset
by the faster clearance time of iodine from the thyroid
glands. In the end, the study's calculated dose factors
were very close to the calculated dose factors of the International
Council for Radiation Protection (ICRP).
Calculation of Excess Risk. Next, the study examined
thyroid risk per unit of radiation dose. The literature
has established that x- and gamma radiation of the thyroid
causes thyroid cancer as well as adenomas to people exposed
under age 15. Relative risk is a factor by which
the background risk of cancer is increased by a given iodine
dose. Absolute risk is an average number of cases
of thyroid cancer observed above the expected amount for
ten thousand person-years of exposure.
The sources of relative risk factors were defined for young
children (<14 years) came from the 1995 National Cancer
Institute (NCI) study of Ron et al; the atomic bomb survivor
studies provided those for older adolescents aged >14
years. The studies showed no effects exposure above age
40. Females are generally more sensitive than males.
Modifying factors include the relative effectiveness
of I-131 compared to external radiation by X- or gamma rays,
and age at exposure (e.g., 1.0 for children aged <5,
.2 for those aged 10-14 years, etc.). Those most exposed
are those aged <5 years. Above age 14 involves a different
relative risk factor. Females are .2 to five times as susceptible
as males. Each value between .2 and 5 had its own probability;
and compared to external radiation, iodine ranged from equally
effective to five times less effective.
Background risk was determined with the Tennessee
Department of Health's thyroid cancer incidence rates from
1988 to 1995 for all Tennessee counties except the four
counties around Oak Ridge. Most thyroid nodules are benign,
and ultrasound finds more nodules than palpation of the
thyroid glands. But since only ~28% of thyroid cancers are
diagnosed and reported, the total possible cancers could
be 3-4 times the number estimated in this study, based on
clinical diagnosis. There is evidence of radiation exposure's
association with non-neoplastic thyroid diseases such as
autoimmune hypothyroidism. These are discussed in the report,
but the incidence rates of benign tumors or autoimmune diseases
were not estimated.
Other variables were reflected in the study report's
contour data plots of concentrations in the environment
media; locations, age, and gender of the receptors, and
diets (four were modeled, including those who drank cow's
and goat's milk). A plot of thyroid cancer for people born
in 1952 who ate local produce and drank a backyard cow's
milk showed a pattern of contamination, with dose patterns
roughly following the ridge and valley terrain from the
southwest towards northwest. Concentrations decreased with
distance out to the 38 km. The nine birth years were similarly
charted to bracket the exposure, keeping in mind that RALA
releases were from 1944 to 56.
At points of exposure, females born in 1952 received the
highest exposure, higher for those drinking backyard cow
milk. The influence of local fallout from Nevada Test Site
(NTS) atmosphere weapons testing was added to the study
doses. Bradbury was one of the most affected locations,
with doses dominated by the X-10 releases. Its upper bound
was 200 centiGrays (or 200 rad) compared to the 48 from
the NTS fallout.
Estimation of health effects included estimation
of the number of thyroid cancers expected between 1950 and
the year the 2020 from the contamination of milk from X-10
releases. The calculations of average time and space concentrations,
volumes of milk produced in the area, and the dose and risk
factors earlier described, produced an expected 6-84 excess
thyroid cancers within 38 kilometers; 1-33 from backyard
cow milk consumption; 14-103 excess cancers within 100 km,
and 25-149 within 200 km. Most of those cancers could be
expected to occur after 1970; a few could occur up to 2020.
Some changes were made to the I-131 report between November
of '98 and the June 1999 final report. A written summary
of all of the changes showed most of them to be typographical
or made to facilitate distribution (printed, electronic),
or to emphasize points. Two areas of controversy were somewhat
de-emphasized: 1) non-neoplastic thyroid disease, and how
strong a statement could be made about how many other thyroid
effects would be expected beyond thyroid cancer; ad 2) comparisons
made with the Tennessee disease registry between thyroid
cancer incidence for the four local counties compared to
the rest of the state. A basic comparison between the four
local counties and the rest of the state implied one conclusion;
but when estimates of the uncertainty of observed differences
in thyroid cancer for whites and blacks, and comparison
of thyroid cancer rates among whites in the four counties
to whites statewide, implied another conclusion.
Dr. Peelle summarized the lack of monitoring and late recognition
of the milk pathways of contamination. He noted that Oak
Ridge city residents and workers were not highly exposed
at work because the air inhalation was not the important
pathway. Only those aged 5 and drinking a lot of milk were
at high risk, particularly those who drank goat's milk.
There was a large range of risk. Some thyroid cancers occurred,
but most were within 25 miles, even though the highest-risk
individuals were right across the river. The large number
of exposures at a lower risk related to most cancers, which
total perhaps a couple of dozen. That is the scale of the
problem. Finally, he stated that the threshold of risk from
a radiation dose to the thyroid would not be a very large
problem because the risk was very small for a large number
of people. Nonetheless, the study assumed that there was
no threshold of risk, the conservative path.
The ORHASP issued nine recommendations, most dealing with
the study's body of work. But the first recommendation,
thought by most of the panel to be the most important, pertained
to communication to the public and their perceptions of
the problem. The residents' concerns often appeared unrelated
to the most significant releases identified. A series of
initiatives and public health activities were was recommended:
ensuring that physicians get information so that they can
look for thyroid problems; strong consideration of a clinic
to evaluate those who may have been affected; and advice
against doing an epidemiological study of some of the contaminants.
The ORHASP members remain fairly certain that this is not
a feasible study, even though they are convinced that there
have been thyroid cancers. They believe that meaningful
results will be prevented by either a large cohort diluting
the number of risk-associated cancers, or such a small number
at high risk that there would not be enough study power
to detect the association.
Discussion, held after a short break, included:
-
Dr. Eklund: How did the release estimates change
during the I-131 project? Dr. Widner: The final
report describes the decline from the 1996 rough screening
assumption of an 80% iodine efficiency capture, through
more detailed analysis of, principally, the scrubber
efficiency using the uncertainty analysis of the Monte
Carlo assessment.
-
Mr. Manley: What happened to the workers involved
in the X-10 and Hanford incidents? Those in the
building immediately left and stayed away at least 12
hours due to high radiation levels. Thyroid counts on
those workers have been reviewed, but there was no evidence
of long-term follow-up found. Dr. Peelle was present
that day, and reiterated that iodine most affects children
under age 14.
-
Ms. Sonnenburg: Where did the figure of 28% of
the total thyroid cancers in population being diagnosed
and reported come from? That is a nationwide average.
Dr. Hoffman added that this information comes from the
Institute of Medicine IOM) in Washington, D.C., which
reviewed the National Cancer Institute (NCI) study on
I-131 and fallout. They found that diagnosis of existing
thyroid cancers in a population depends on the physician's
practice (the common physical palpation of the neck
or ultrasound). But the ratio between what is diagnosed
and what actually exists in a population comes from
autopsy data. Many people who have thyroid cancer die
of something else.
-
Dr. Frome: What kind of assumptions about the distributions
and the various risk groups in the geographic area did
you make in doing your calculations of excess risk?
The assumptions include what the amount released and
what fraction of contaminated milk was consumed by children
under age 15, regardless of where they lived, to produce
a reasonable estimate of the expected excess cases,
and the assumption that over age 15 the risk is markedly
less. Dr. Frome: How do you know that the parameters
for children would differ from those for adults?
That isn't known, exactly; the the range of scientific
confidence is known, which is expressed as an uncertain
variable. But the main difference is in the mass of
the thyroid; any other metabolic difference between
children and adults is small.
-
Dr. Brooks: There appear to be inconsistencies
in the report about the scrubber, regarding practices,
and that the sparse performance data provided is experimental
data that lies well outside the assumed range of distribution
function for scrubber efficiency. This ignoring of book
parameters, without any definitive discussion of why,
raises questions. And, the Knoxville reference diet
is urban, with no backyard cows, differing from that
of rural areas such as Oak Ridge. What difference
would the predicted rates be with a more exurban diet.
Dr. Peelle responded that the diet was not Knoxville's,
but commercial milk, and in 41 locations. Average numbers
are given for commercial milk from the region.
- Ms. Stoke objected that commercial milk in this area
came from backyard cows; in fact, some of Knoxville's
milk came from her grandfather's farm. And even today,
metropolitan areas still have local producers. She
asked if the tumor registry data was available to the
public? Dr. Bill Moore, the Tennessee State Epidemiologist,
reported that the cancer registry is alive and well, but
is 3-4 years out of date. It is updated every day, but
this a passive surveillance system that depends on voluntary
reporting by institutions and physicians. Delays in reports
are normal. Requests for information should be sent to
Dr. Tony Bounds, who is in charge of the state registry,
in Nashville.
SENES
Perspective
Dr. Owen Hoffman was the task leader for the I-131 study,
which took four years to do. The final report on the I-131
task was delivered by the City of Oak Ridge to the State
of Tennessee in November 1998. Since then, SENES has put
the report contents in a computer code, which he demonstrated.
But first, Dr. Hoffman discussed the health implications
of combined exposure to multiple sources of I-131 other
than the RaLa releases. He defined the measurement term
of one rad as 1/100 of a Gray, or one centiGray. A very
high dose of about 2000 centiGrays, the dose used by therapeutic
medicine, can destroy the thyroid gland. The patient takes
hormone replacement for a lifetime to offset hypothyroidism.
The only environmental examples of such thyroid destruction
are the few children on Rongelap, Marshall Islants, who
in 1954 were exposed to fallout from Shot Bravo, the highest
iodine exposure event known. At lower doses (<100 cGy/rad),
thyroid cancer or benign thyroid growths called neoplasms
can occur. The greatest risk is in females, especially those
exposed in childhood, and to children in general. There
is a 90% survival rate 20-30 thirty years after thyroid
cancer treatment; it is seldom fatal.
The limits of epidemiological detection (ability to find
an effect that is truly present) is between ~10 and 30 cGy.
But the inability of an epidemiological study to detect
below these levels does not mean that the risk is zero.
The recent literature indicate that the risk for I-131 is
not much different than any other type of radiation in inducing
thyroid cancer (as seen in NTS and Chernobyl exposures).
Epidemiological studies' statistical power is compromised
due to the very high uncertainty of the dose estimate, and
low statistical power most likely prevents the ability to
see an effect. The NCI recently agreed that the weight of
uncertainty leans toward no difference at all for I-131
than from other radiation exposures; that there is no dose
below which there is no risk; and that the risk markedly
decreases with increasing age at exposure, with only a small
difference due to gender. The NCI's updated epidemiological
tables parallel the confidence intervals of the risk factors
for excess risk per Gray found by the Oak Ridge dose reconstruction,
and recent epidemiological data of children exposed to the
NTS fallout and Chernobyl are similar.
Other health outcomes from exposure to radiation
include non-cancerous growths to the thyroid and benign
nodules; thyroid function diseases such as autoimmune thyroiditis,
such as Hashimoto's hypothyroidism (under-active thyroid)
or Graves Disease (over-active thyroid). In some cases,
these affect the quality of life more than thyroid cancer.
The IOM's summary of the evidence indicated that the risk
of autoimmune thyroiditis can occur at doses <100 cGy,
but it is unlikely at <10 cGy. Therefore, the elevated
risk is plausible at a range of 10-100 cGy.
Sources of I-131 exposure include medicines, nuclear
facility releases (especially from accidents), and nuclear
weapons testing. SENES believes that the release estimates
from Oak Ridge should include the caustic scrubber and X-10
releases and be raised. In addition, Hanford released ~900,000
Curies (Ci) of I-131 (a curie is 37 billion disintegrations
of radioactivity per second; the international unit is the
Becquerel, one disintegration per second). The Savannah
River site released ~65,000 Ci in the most recent estimate;
Chernobyl released ~50 million Ci; the NTS released 150
million Ci and the Marshall Island testings released ~8
billion Ci. The amount from the former Soviet Union has
yet to be totaled.
About 100 atomic tests were detonated in the atmosphere,
from towers, tethered balloons, or test sites. Depending
on the height of the mushroom cloud, the wind carried these
clouds in different directions, but mostly to the east.
The U.S. depositions were estimated by mathematical models
from the deposits on a gummed film network, 8½x11" sheets
of paper placed at breast height and changed daily. The
models calculated the gross beta activity to how much I-131
would be in air, and then adjusted for local amounts of
rain (which aided deposition). The measurements in the gummed
film areas are more certain than those a distance from them.
Fallout raised radiation background exposure substantially,
and that occurred at the same time as the X-10 releases.
Dr. Hoffman showed the NCI's map of the U.S. with the average
I-131 dose per person for each U.S. county. Most of the
dose appears to be in the west and some in the northeast,
but it focuses on the average individual and the average
date. The map of those who were children at the time (born
in 1946) and drank millk showed no counties with an average
dose of >30 rad; 130 counties with 10-30 rad exposure;
1,600 counties between 3-10 rads, for children born in 1946.
But the same counties, for children born in 1952 who also
had average milk consumption, showed six counties with an
average dose of ~30 rads; 914 at 10-1000 rad; and 700 at
3-10 rad. And those with the same birth date but drinking
higher-than-average amounts of milk, 236 counties had an
average dose of 30 rads; and 1912 had doses at 10-30 rads.
The Oak Ridge dose reconstruction was the first to add
in the impact of NTS fallout. The map of Tennessee, initially
seemingly unaffected, is included in the >3 rad county
dose. That dose is high enough to induce auto immune thyroiditis,
particularly if a child drank goat's milk and to a lesser
extent backyard cow's milk, regardless of the location of
residence. Fallout exposure alone places one into the risk
range for auto-immune thyroiditis.
With that, Dr. Hoffman demonstrated the updated SENES dose
and risk calculation program for combined exposures locally.
It included I-131 released from X-10, the original estimates
from the dose reconstruction, the caustic scrubbers and
other ORR releases; and the NTS fallout, but not that from
the Marshall Islands or the former Soviet Union. It follows
the milk pathway and estimates probable doses with a Monte
Carlo simulation. The latter produces subjective probability
distributions for each uncertain parameter, through a mathematical
model that produces alternative realizations of the true
(but unknown) value of the thyroid dose, and eventually
of the thyroid risk. Its result is expressed in the 95%
confidence interval of one central estimate. The program,
IRAD, or Interactive Risk and Dose Calculator, is a prototype,
which Dr. Hoffman hopes to put on the Web for public access.
IRAD does not yet address the additional contribution of
leafy vegetables or cottage cheese, but those can be added.
He used the program to calculate the dose to a Bradbury
resident who was female and born in 1952, present in the
Oak Ridge area from to 1957, and drank milk from a backyard
cow (the program can also calculate for regional or local
commercial milk and dairy goats). The calculations showed
the Bradbury NTS fallout to be less of a risk than the X-10
RaLa releases. Those are an order of magnitude higher than
any regulatory standard. The excess lifetime risk for NTS
fallout ranged from several chances in ten thousand up to
~2 in 100 from X-10, in a total range of ~2 chances in 1000
to 7 in 100.
From a medical point of view, these are minimal risks;
a person currently free of disease is likely to remain so.
But if a person has thyroid cancer, the probability of causation
comes into question. That, in fact, is the main focus of
the current update of the 1985 radioepidemiological tables,
the estimates of which parallel the dose reconstruction's
1998 estimates. They concluded that NTS fallout alone provided
an 11-80% chance of causing an existing disease; or a 26-94%
chance that X-10 releases had, for a backyard cow scenario.
Dr. Hoffman did the Oak Ridge calculations for both regional
and local commercial suppliers, for an average consumption
of three 8-oz. glasses a day. Since most of the milk came
from regional dairies, the ORR releases were diluted, resulting
in lower risks than those from a backyard cow milk in Bradbury.
For X-10 operations, they were again lower, ~3:10,000 chances,
and an upper limit of 3:1000. The probability that an Oak
Ridge resident's thyroid cancer was caused by ORR exposure
is low, although NTS fallout could still be a substantial
contributing factor. Dr. Hoffman then did the same calculations
for local commercial milk, which raised the Oak Ridge milk
dose from <1 rad to ~12, and raised a probability of
causation (>50% for Oak Ridge releases). Subsequently,
Dr. Hoffman calculated a dose for a member of the public,
Ms. Janet Michell.
He noted that the present estimates of the probability
of causation exceed the eligibility criteria recommended
for compensation and care of DOE workers (i.e., the upper
99th percentile of the probability of causation exceeding
50%). That means that if the present-day rules for compensation
of workers were extended to children, those who were children
in the 1950s would qualify for the compensation and health
care if they drank milk and currently have thyroid cancer
or a thyroid nodule.
To Dr. Hoffman, this provided a sufficient basis for the
Subcommittee and ATSDR to consider potential public health
response, but not necessarily mass screening for thyroid
disease, due to the danger of false diagnosis. But screening
of a targeted population could be done; those with thyroid
disease exposed childhood and who drank milk. He also called
for quantification and adjustment of the RaLa releases with
regard to the caustic scrubber, and rather than using annual
conditions, he would match release periods with the prevailing
meteorological conditions, terrain, and time-varying releases,
as well as the cumulative effect of exposure to all fallout
radioiodines including the NTS, Marshall Islands and Soviet
Union.
ATSDR
Perspective
Dr. Michael Grayson, a health physicist and environmental
engineer with ATSDR, reported their review of the dose reconstruction
document and the ORHASP report of the dose reconstruction's
technical matter. ATSDR did so due to interest in using
these two documents in its public health assessment, and
to determine if the ORHASP document was an appropriate way
to communicate with the local residents. Dr. Grayson related
the results of ATSDR's technical review of for both documents
in a general overview.
In the dose reconstruction technical review experts
examined at three primary areas:
-
The source term analysis was generally found
to be complete and reasonable. While other assumptions
could be made, the range of the risk was not thought
likely to change dramatically.
-
The sensitivity analysis produced a very wide
range of comments about its quality, from appropriate,
to reasonable, to questionable (i.e., it should not
be used further in the work on uncertainty and sensitivity
analysis). That reviewer preferred to use the central
values rather than the upper and lower bounds of the
dose distribution. However, all the reviewers approved
of the use of Monte Carlo simulations in the sensitivity
and uncertainty analyses. They all called for more detail
and justification by the report authors of their choice
of input parameters for the code (i.e., again, preferring
to use a central estimate over upper and lower bounds).
-
The public health effects conclusions were
shared by the reviewers and most of the presenters this
day: that doses and the risks were too small to have
significantly affected Oak Ridge residents, although
certain groups had higher risks (females born in 1952,
people between infancy and the age of five years during
the times of the releases, etc.). The reviewers found
the dose reconstruction report to clearly describe the
potential adverse health effects from iodine exposures,
and to give a good explanation of the differences between
relative or hypothetical risk and actual risk. The dose
reconstruction was based on specific diets, so those
risk values apply only to those specific diets.
- In short, the reviewers found the methodology to meet
the current standards, that the report covered all aspects
of the dose reconstruction, and that generally the outcomes
reported were reasonable.
ORHASP Report Review. Dr. Grayson then reported
the comments to ATSDR on the ORHASP document, "Releases
of Contaminants from Oak Ridge Facilities and Risks to Public
Health". In general, all the technical reviewers found the
technical information to be well conveyed for the general
public, and the recommendations to be reasonable. Improvements
suggested included clarification for the general public
of why an epidemiological study may not detect any increased
risk; to include zero in the lower bound of the risk estimates;
and to emphasize the central estimate and de-emphasize the
lower and upper bounds of uncertainty.
Committee
Discussion
included the following:
-
Mr. Pardue congratulated Dr. Hoffman on his presentation
and the model. He asked if he correctly understood that
Dr. Hoffman considered the risk of thyroid cancer to
be greatly increased in the U.S.; and that he basically
agreed with ORHASP report except that it should include
other sources. He asked if Dr. Hoffman's estimate
that this would increase the worst-case scenarios by
only a factor of two or three over the few dozen found
would raise total number of those affected by the Oak
Ridge area releases to only 50-60? Yes. The re-evaluation
of the caustic scrubber could increase or decrease the
releases, but his intuition, based on the work at Hanford
and to be done in Idaho, is that the estimates will
not change much. However, if the probability of causation
for workers is extended to the public, small differences
will make big differences in eligibility. That would
be the only reason to fine-tune those results.
- Mr. Pardue: How many people might be eligible for
that compensation? Thyroid cancer is rare; about
0.06% for females over a lifetime. Autoimmune thyroiditis
is very common, but not a dose response compensation matter.
Public
Comment
Mr. Mike Napp asked what other I-131 releases
at the Oak Ridge site were not included in the original
I-131 source term? Dr. Widner responded that one not included
in the evaluation, as mentioned in his presentation, was
iodine isotope production processing. It was lower in relative
importance because only a relatively small number of fuel
solutions were fed through that process. And, since the
desired end product was the I-131, they went to great lengths
to capture that, so the initial evaluation found it of less
importance than the RaLa processing. For the one run where
the scrubber ran dry for a portion of the run, iodine would
have been released; analysis did reflect essentially no
removal for a fraction of that dissolving batch. Did
that occur late in the program or near the beginning the
program? The details would have to be re-reviewed,
but it may have occurred late, which probably be lower in
concentration. Was the line loss accounted for in the
source term? (Yes). So if the line from the stack
to the scrubber is counted as a removal, then the median
removal efficiency would ~98 ½%, right? Yes.
Ms. Janet Michell asked if Dr. Hoffman wished
to respond to anything in Dr. Widner presentation. Dr. Hoffman
noted that one of SENES' recommendations about the dose
reconstruction was to delete the early mathematical model
of the caustic scrubber, which was clearly overstating the
efficiency by orders of magnitude. It was not deleted, the
option of the prime contractor. SENES also objected to some
changes made in the report that were more than editorial,
and made without contacting SENES.
Ms. Michell commented that since 1981, hospitals have been
required to report to the state tumor registry, but the
Oak Ridge hospital was the last to comply. She had heard
of hundreds of thyroid cancers diagnosed and reported to
the state Department of Health particularly in 1998 and
1999, but the I-131 report used the "last incidence data"
from 1995. Those data after 1995 have been repeatedly requested,
but never provided. Dr. Moore, the Tennessee State Epidemiologist,
did not understand why she had not been provided with that
information, albeit labeled "preliminary." He agreed to
help her get it. However, he also pointed out that preliminary
information is relatively worthless because of incomplete
reporting and incomplete statistical analysis. He was currently
analyzing state cancer sites through the end of 1996. The
1997 and '98 data are still too incomplete to be of any
help to his studies.
Dr. Karl Markiewicz asked about the Tennessee gummed film
network, which operated in Knoxville from 1956-57. Did
the releases from Oak Ridge affect that film, or was there
a contribution on that film? Dr. Hoffman answered that
intuitively one would think so, but they did not measure
radioactive iodine, but the non-volatile fallout. That was
used in a mathematical model to calculate the iodine component.
The Oak Ridge releases would not have affected the gummed
film.
Ms. Jeanne Gardener, a former K-25 worker, advised
ATSDR not only to do the surveys, but also to listen to
the information of offsite residents. She noted the difficulty
for an ill worker or a resident to have to wait all day
for only two 15-minute public comment periods at this Subcommittee's
meeting, and also asked if any sick workers or sick residents
were members. Mr. Pereira responded that ATSDR has made
strong attempts to have such representative persons. For
many personal reasons, including financial issues and potential
risk of their benefits, those people identified to date
have chosen not to participate. ATSDR is again attempting
to invite a sick worker's participation on the panel, which
now has members who work or have worked at the facility.
He encouraged applications from sick workers. Ms. Gardener
reported that she herself is a good example of a person
on disability who cannot receive any compensation for participating
on a panel such as this. Knowing that, she wondered aloud
why it was set up that way. Dr. Davidson noted that much
of the Subcommittee's work is done through its work groups,
whose meetings are generally short (~1½-2 hours), and encouraged
public participation.
Ms. Michell acknowledged ORHASP's hard work, but reminded
the committee that DOE had publicly admitted that their
records are flawed and inaccurate. Much of the I-131 report
is based on that unreliable data. She also asked that the
committee over time address other toxicants that of concern
that are not included in the report. She charged that the
EPA used this report and the long time period of nine years
to avoid the human health hazard evaluation that is required
by law for Superfund sites. EPA needs to fulfil its obligations;
this report does not take the place of a human health hazard
evaluation. She noted that DOE this study and this Subcommittee.
Dr. Davidson confirmed that other contaminants of concern
will be addressed in future meetings.
Dr. Davidson read Mr. Napp's question to Dr. Peelle of
why the Oak Ridge signature contaminants of nickel,
strontium, cesium, and chromium, which are in residents'
bodies, were not included in the Phase I evaluation, and
why was it not peer reviewed? Dr. Peelle was not involved
with ORHASP in Phase I. While he thought that some of those
elements were reviewed, he recalled that some information
could not be released during Phase I.
Mr. Napp: Does the resignation of Dr. Lands from the
Subcommittee opened a seat that could be filled by a sick
self-identified resident? Dr. Davidson said yes; that
was to be considered on the following day by the Subcommittee.
Mr. Napp: Dr. Hoffman's analysis of the ORHASP I-131
report task seems to contradict Dr. Grayson's report, in
which at least one reviewer found no health effects in the
Oak Ridge area. Dr. Hoffman confirmed that. There
are public health concerns, especially considering that
the I-131 background was elevated over natural background,
so he would not condone a lower bound set at zero. The ATSDR
reviewers were also more restrained than he would be about
the need for a public health response. But he noted that
all four of them are health physicists, none are epidemiologists
or chemical engineers; and the difficulty of doing such
broad reviews.
Continuation
of Subcommittee Discussion.
-
Dr. Frome: Was thyroid cancer an underlying cause
of death in the autopsy data, if not the underlying
cause of metastasis? The under-ascertainment of
thyroid cancer is unrelated to the causes of death on
death certificates.
-
Dr. Brooks strongly took issue with the analysis related
to the caustic scrubbers, found the design analysis
of little value, and the assumptions improper. He cited
the report's contradictions and lack of evidence for
the scrubber, which for him called intot questioned
the legitimacy of the study results. He asked if Dr.
Hoffman wished to totally review the assumptions of
the caustic scrubber, which the latter confirmed. Dr.
Brooks and Dr. Widner debated the report until Mr. Pereira
suggested they resolve those questions privately.
-
Ms. Sonnenburg: The Oak Ridge dose reconstruction
summary notes that airborne releases from Y-12 were
independently estimated at 5-7 times those reported
by DOE. Where did that came from, and did you use the
DOE statistics or did you multiply it by some other
number? Dr. Widner responded that the raw data
from the stack sample measurements were used to independently
calculate the releases. A lot of the depleted uranium
was not tracked as carefully as the enriched ore, and
some was not included in the official release totals,
but the study did a more thorough accounting. The study's
estimates of uranium release of Y-12 and K-25 released
were seven higher than DOE's, and they used those numbers.
The efficiency of the scrubber treatment is definitely
an important part of this.
-
Mr. Hill: Please tell us more about the ability
of workers to receive compensation. Are the Veterans
Administration and the Labor Department using the probability
of causation in their adjudication of claims for all
cancers? Dr. Hoffman: Yes. A White House Order
now requires the use of the 99th percentile to ensure
that the exposed individual gets the benefit of the
doubt. So, if the extreme upper end is 50%, current
legislation makes that ineligible for compensation and
medical care. He personally disliked using the upper
99th percentile because it is too unstable, but there
seems to be no room for discussion on this, and it goes
into effect in July for workers only. Mr. Bill Murray,
of ATSDR, reported that Mr. Larry Elliott of NIOSH could
provide more details about this, and offered to provide
his e-mail address for any questions. Ms. Michell advised
the workers not to get their hopes up; they must have
one of only a few cancers, and be able to prove that
it was caused only by those few DOE facilities covered.
-
Mr. Hill: In view of the fact that the government persisted
that there was no risk from radiation even as the experts
proved there was, and the public's distrust results
from that, he advised that it would be unwise to use
that term in this setting.
-
Ms. Kaplan drew the members' attention to related material
that she had developed and distributed, announcing that
the second report had been briefly reviewed by Dr. Hoffman,
but not yet by the Local Oversight Committee.
-
Mr. Akin: Why are females and children aged 5 years
more susceptible, and is that true for all cancers or
only thyroid endpoints? Dr. Hoffman: For all thyroid
endpoints, females have a higher background risk than
males. The ability of radiation to induce an excess
risk is well documented, but the actual underlying mechanism
making the background risk for females and children
higher than that for exposed males is unknown. While
the endocrine systems of both sexes seem to be the same
in childhood, something seems to happen later in life
that changes that (i.e., precursive damage early in
life to DNA that manifests itself later). But excess
relative list (excess relative to background), if mathematically
normalized to background, shows little difference between
males and females.
-
Mr. Lewis: Since the past diagnosis of thyroid
cancers may be underestimated, and cancer registries
are of little help, is there enough present knowledge
to extrapolate to what might have occurred in the past?
Dr. Hoffman: The uncertainty is present, but is
not infinite; some conclusions can be supported, and
some not. Some of the report's elements such as the
caustic scrubber, that may have been missed, can be
re-evaluated. But disease registries did begin late,
and the use of palpation rather than ultrasound to detect
a thyroid nodule did lead to under-ascertainment. Even
with ultrasound, a biopsy may be inconclusive, and some
may have had surgery to be on the safe side. That is
why mass screenings can be dangerous, potentially leading
to many unnecessary surgeries due to false positive
results. Some of the inconclusive studies in the past
were so because they focused on incidence; only examination
of national data on thyroid cancer mortality produced
a statistical relationship between fallout and thyroid
cancer.
-
Dr. Davidson read a public comment by a UT professor
into the record: Why were only DOE-friendly people
asked to review the I-121 study? Dr. Davidson also
asked if there is information is available on the
relative intake of I-131 and the uptake into the thyroid
in children versus adults, and in girls versus boys,
because differences and disease outcome can either be
due to different amounts getting into the target tissue
(the thyroid) or an inherent sensitivity in one or the
other. Dr. Hoffman reiterated that there is little
difference between boys and girls in terms of either
milk consumption or transfer from milk to blood, and
blood to the thyroid. In the earliest months of life
such as the neonatal period, the uptake from blood to
the thyroid would be high (~60%) versus ~20% normally.
The biggest difference between children and adults is
that children drink more milk and have smaller thyroids,
which produces a difference of 10-20 times in the dose
to the thyroid. But while there is no difference in
dose between males and females on the NCI Website, there
is a difference in risk.
- Ms. Kaplan stated, as a person who had a false positive
result and had the surgery, that having a surgery and
living for any length of time with the terror that one
might have cancer is not a trivial thing; it is really
life-altering experience.
Closing
Comments
Dr. Davidson mentioned that the iodine issue would be addressed
in the ORRHES Work Group, and again invited any of the public
wishing to become involved to attend the work group meetings.
With no further comments, the meeting adjourned at 7:30
p.m.
<< Back Next
>>
|