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ORRHES Meeting Minutes,
March 3, 2003
Work Group Sessions
AGENDA WORK GROUP PRESENTATION
Barbara Sonnenburg reported that future topics for discussion before
the Subcommittee should be presented to the Agenda Work Group before
future ORRHES meetings. Jerry Pereira’s and Burt Cooper’s
reports (Administrative update/project update) will be a part of every
ORRHES meeting. Jeff Hill commented that the Agenda Work Group has done
well arranging agenda for ORRHES meetings to date.
GUIDELINES AND PROCEDURES WORK GROUP
On behalf of Karen Galloway, Kowetha Davidson reported that the Guidelines
and Procedures Work Group does not have a report.
HEALTH EDUCATION NEEDS ASSESSMENT WORK GROUP
Theresa NeSmith reported that the focus groups of the Needs Assessment
have been completed and the information from the focus groups will be
added to the information from the telephone surveys and the key resource
interviews to compile the final Needs Assessment report. The final Needs
Assessment report should be available May 30, 2003. The plan is for the
Needs Assessment Work Group to have the opportunity to look at the report
before it is made available to the entire Subcommittee.
The Savannah River site Needs Assessment report has been circulated
to the ORRHES, and a copy of another health education needs assessment
report was distributed to ORRHES members (Fallon, Nevada site in Churchill
County). This is another example of a needs assessment that used focus
groups. Theresa NeSmith encouraged Subcommittee members to look at these
reports and the processes and recommendations of those needs assessments.
This can be useful for discussions about the format of the Oak Ridge
needs assessment.
Barbara Sonnenburg asked when the Needs Assessment report
will be made public. Theresa NeSmith responded that it will
be made public after the Needs Assessment Work Group reviews
the report (as previously requested by ORRHES). Barbara
Sonnenburg asked if the report could be presented to the
entire ORRHES. Theresa NeSmith responded that that would
be fine, and asked that direction be given whether to provide
the report to the Needs Assessment Work Group or the Subcommittee,
or both. James Lewis commented that the report could be
given to both the work group and the Subcommittee or to
the work group first before it is brought before the full
Subcommittee. Kowetha Davidson suggested that the work group
review the report first before it is brought to the Subcommittee,
in the same manner that public health matters are addressed
by the PHA Work Group before they are considered before
the full Subcommittee.
Barbara Sonnenburg asked for the final titles of the focus
groups and how many people were in each focus group. Theresa
NeSmith responded that she does not know how many people
were in each focus group and knows only in general the focus
groups that were conducted. Theresa NeSmith has not been
involved in the details of the focus group recruitment and
conduct and has not asked for the exact names of the focus
groups because that information will be in the report. This
is consistent with ATSDR trying not to be too involved in
the needs assessment process so that the process does not
go through the ATSDR internal review board (IRB) process.
Barbara Sonnenburg asked that ATSDR request that the final
report list the titles of the focus groups. Theresa NeSmith
responded that she will ask that the report list the focus
groups that were recruited. Kowetha Davidson commented that
the Subcommittee can ask for the listing of the focus groups
in the report if it is found during review that the report
does not list them, but if the George Washington University
IRB will not allow release of the list of focus groups them
the Subcommittee will not be able to get that information.
Tony Malinauskas asked whether a draft of the needs assessment
report will be available for public comment. Theresa NeSmith
responded that usually the needs assessment reports are
not open for public comment, but sometimes feedback from
the participants in the needs assessment is obtained. If
the report were sent out for public comment there would
not be much room for them to make comments because of the
nature of the content of the report (e.g., results of telephone
surveys). Tony Malinauskas also noted that if the Subcommittee
would request that the focus groups be identified in the
report then the responsibility would be with the authors
of the Needs Assessment report to justify why they do not
want to include that information in the report.
Barbara Sonnenburg noted that the Needs Assessment Work
Group expended much effort identifying what focus groups
they thought were important and what “key informants”
should be contacted and the work group would like to know
whether the work groups and key informants that they identified
were actually used/contacted. Theresa NeSmith responded
that in the December 2002 ORRHES meeting she distributed
a list of the categories for the focus groups, which can
be compared to the focus groups identified by the work group
to see which groups were recruited. In addition, most likely
the key resource interviewee identities are kept confidential
in accordance with the specifications of the IRB. Barbara
Sonnenburg responded that the work group would simply like
to know how many of its submitted suggestions were contacted.
Theresa NeSmith responded that she can get an answer to
that question. Theresa NeSmith added that the input provided
by the work group was substantially used.
Regarding the Needs Assessment, James Lewis commented that:
1) the timeliness of getting information on the Needs Assessment
back to the ORRHES has been a problem, 2) the Needs Assessment
is excessively secretive/mysterious, making it very difficult
for the Subcommittee to endorse the Needs Assessment as
a means for communication with and education of the public.
James Lewis expressed frustration at not being able to get
answers to questions about the Needs Assessment or even
find out the costs involved in the Needs Assessment. James
Lewis reviewed the sample needs assessment report (Savannah
River Plant) provided by ATSDR and in the recommendations
in the example Needs Assessment found recommendations/issues
that the ORRHES Needs Assessment Work Group has discussed.
The Subcommittee should be provided something concrete back
from the Needs Assessment process, which has been ongoing
for about two years. Theresa NeSmith encouraged that Subcommittee
members review the report when it becomes available and
at that time comment and request any information that the
Subcommittee believes should be included. Reiterated the
confidentiality issue for the Needs Assessment as part of
why info on the Needs Assessment has not come to the ORRHES
during the process.
Pete Malmquist asked where the focus groups were held and
whether the health needs assessments performed by each county’s
health department were incorporated into the ATSDR Needs
Assessment? Theresa NeSmith responded that the results of
the county health department health needs assessments were
reviewed during the ATSDR Needs Assessment. Theresa NeSmith
reminded Subcommittee members that the confidentiality aspects
of the needs assessment are used to encourage people to
participate, and that the needs assessment process is different
from other assessment processes.
Elmer Akin commented that the issue being discussed is an issue of trust
and ORRHES needs to be able to trust the needs assessment
process and report. Elmer Akin suggested that perhaps there
is something that can be done to increase the level of trust
that the Subcommittee has in the needs assessment. Theresa
NeSmith encouraged the Subcommittee to wait for the report
to determine the extent to which Subcommittee input was
used. Theresa apologized for not having much knowledge of
details personally.
COMMUNICATIONS AND OUTREACH WORK GROUP
James Lewis reported that the Communications and Outreach Work Group
(COWG) has met twice since the December 2002 ORRHES meeting. The work
group has developed six recommendations to possibly vote on today:
- ATSDR,
in collaboration with ORRHES, develop a briefing book to be provided
to the media and key groups, and provide periodic updates to the briefing
book.
- ATSDR, in collaboration with ORRHES, develop a semi-annual newsletter
for program overview and updates.
- ATSDR, in collaboration with ORRHES, develop an issue-based cross-referenced
index of key issues, based on the various agenda from meetings, to
be placed on the website.
- ATSDR place a summary of the project plan on the website and place the
public health assessment process flow sheet for public health assessments
on contaminants of concern, depicting ATSDR and ORRHES work group interactions,
on the website.
- ATSDR supply resources needed to develop briefing papers for focussed
PHAs on each contaminant for distribution prior to public release and
ORRHES meetings.
- ATSDR make a presentation for each contaminant of
concern in one central location (no specific community). If interest
is expressed for another
presentation in another community, the request will be made to ORRHES
and the ORRHES will determine the need for another presentation.
Tony Malinauskas asked how members of the public learn about ORRHES meetings.
James Lewis responded that the primary means is advertisements/announcements
in various newspapers. Tony Malinauskas commented that he has not seen
announcements in the Roane County News. La Freta Dalton confirmed that
ORRHES meetings are advertised in the Roane County News, the Clinton
Courier, and the Oak Ridger. Advertisements are run on Friday and Sunday.
Press releases are submitted to other newspapers. The agenda for ORRHES
meetings appear on the ORRHES website, the Federal Register includes
ORRHES meeting announcements. The DOE newsletter also includes ORRHES
meeting announcements.
James Lewis noted that a visit was paid to Kathy Daniels at the Oak
Ridger. Kathy Daniels related that she can not spare the 8 hours of time
to attend an ORRHES meeting, she needs a more detailed agenda to narrow
down when she might attend for particular topics or presentations. La
Freta Dalton confirmed that detailed the ORRHES meeting agenda are posted
on the website.
James Lewis also emphasized the need for ORRHES to develop an infrastructure
to communicate to the public. Kowetha Davidson commented that some segments
of the public are not addressed, particularly those members of the public
who are not “electronically connected”. Kowetha Davidson
asked how the Subcommittee can get information out to the people that
are not electronically connected. Bob Craig commented that the recommendation
for a semiannual newsletter is a very good idea. Lorine Spencer added
that the COWG had the idea of placing copies of the briefing book in
the public libraries and putting the libraries on mailing lists for newsletters
and ORRHES activity announcements. Kowetha Davidson added that there
is a need to develop mailing lists and distribution mechanisms for the
briefing book and newsletter recommended for development. Lorine Spencer
responded that distribution process is being addressed but a proposal
will be reported to ORRHES at a subsequent meeting.
Brenda Vowell asked whether the COWG had considered sending presenters
to speak to groups representing the elderly such as the American Association
of Retired Persons (AARP) about The ORRHES. The AARP is well represented
in many communities. James Lewis responded that the COWG is compiling
a list of numerous groups to visit for presenting outreach information
from ORRHES, the AARP is an appropriate group to include in that outreach
list.
David Johnson commented that the proposed briefing book would be something
tangible to the community that would help increase their “trust” in
the Needs Assessment. In addition to targeting information and presentations
to the AARP it would be useful to target groups such as small rural churches
and persons who are “turned off” by computers and prefer
to talk to a person face-to-face or by telephone. It is possible to use
community volunteer resources to accomplish some of this (e.g., Boy Scouts,
Girl Scouts, 4-H, etc.). These efforts will gain credibility and visibility
for the ORRHES process.
James Lewis added that it is beneficial for ORRHES members to print
information from their computers and post the printed information where
it can be seen by the public.
Brenda Vowell commented that each county has an active health council,
representing a good cross section of the community in its membership.
These people could be used as a means for distributing information to
communities. Lorine Spencer asked ORRHES members to write down any ideas
for target groups or individuals that could be used to help distribute
ORRHES information to the public and forward those ideas to her.
Don Creasia asked how many people (members of the public) visit the
ATSDR field office in Oak Ridge and whether people are getting information
about ORRHES via visits to the field office. Perhaps the resources spent
in the ATSDR field office on communication with the public is not really
an effective way to get information out to people in the community, if
people do not visit the field office. Kowetha Davidson responded that
ORRHES needs to do a better job of getting information out to the public
so that more people will make use of the field office, attend work group
meetings, and attend Subcommittee meetings.
Presentation by Dr.
Karl Markiewicz on the ATSDR chemical screening process for current
and future exposures from soil and sediment.
Overview of Screening Process
Karl Markiewicz presented the process flow diagram for the ATSDR chemical
screening process. The process, as described in previous ORRHES meetings,
includes the following steps:
- Collection of environmental sample analytical
data
- Identify chemicals from the environmental data
- Compile media-specific,
chemical-specific comparison values
Apply the
comparison values to the environmental data to filter the list of chemicals
Determine
which chemicals are eliminated from further review and which are
carried further in the health assessment process Subsequently, the exposure assessment for chemicals that carry through
the comparison value filter is refined, adding more realism to the exposure
assessment values. This leads to determination which of chemicals will
be carried into the public health implications portion of the PHA. In
the public health implications phase, the weight of evidence of chemical
toxicity is evaluated to examine the studies on which the chemical specific
screening values are based. This information is used to assess whether
the final calculated exposure dose represents a public health problem.
The screening process using comparison values is an assessment phase
that is designed to be very conservative. The exposure is assumed to
be at the maximum level of chemical concentration, maximum bio-availability
of the chemical, maximum duration of exposure, and maximum rate of exposure.
that the Comparison values include EMEGs, RMEGs, CREGs. An EMEG is an
Environmental Media Evaluation Guide. ATSDR has these EMEG values for
drinking water, soil, and air. The following hierarchy of comparison
values is used:
- start with ATSDR EMEG comparison values (based on MRL)
- EPA comparison
values RfDs (reference doses) and RfCs (reference concentrations)
- other
EPA comparison values besides RfDs and RfCs such as soil screening
guidance.
The EMEG for soil is calculated as: EMEG in mg/g = (MRL x BW)/IR
where MRL is minimal risk level in mg chemical/kg BW/day, IR is ingestion
rate in grams/day, and BW is body weight in kg (child is 10 kg, adult
is 70 kg). The ATSDR MRLs are derived in a similar manner as the EPA
RfDs and RfCs. ATSDR lists its MRLs and default screening IR values
on the ATSDR website.
An example EMEG calculation was presented for arsenic ingestion in soil
for an adult:
MRL = 0.0003 mg/kg/day (no adverse health effects)
BW = 70 kg
IR = 0.0001 kg soil/day
EMEG = 210 mg arsenic/kg soil (210 parts per million, ppm)
Don Creasia asked whether laypersons accessing the ATSDR website will
know what an MRL is. Karl Markiewicz responded that the concept of an
MRL is explained on the website, but concedes that it is not easy concept
for laypersons to understand in detail. Exceeding the EMEG screening
level does not indicate that health effects occur. The EMEG is a screening
level not a health effect level. Charles Washington commented that the
units are confusing and meaningless in mg/kg/day, could the expression
use so many sized fish consumed per day? People in the area consume a
lot of local fish and locally grown foods so there should be site specific
IR values. Karl Markiewicz responded that in the public health assess
stage ATSDR does relate the units in a more meaningful way, and that
in the PHA ATSDR collects site specific IR values for fish, meat, milk,
vegetables.
Barbara Sonnenburg asked how ATSDR tests for contaminants in the body
in target organs. Karl Markiewicz discussed target organs of various
contaminants. ATSDR sometimes tests body tissues (e.g., urine, blood)
for chemicals but does not routinely test. The tissue that would need
to be tested depends on the chemical of concern. For example, lead is
a bone seeking chemical while uranium goes to the kidney along with most
heavy metals. Kowetha Davidson commented that the amount of a chemical
in the blood generally tells what is bio-available for distribution to
tissues in the body that may be affected by the chemical. Chemicals deposited
in the bone for example are not available, they remain in the bone and
release from the body slowly over time.
Soil Screening Summary Statistics
Karl Markiewicz presented a summary of the results of the ATSDR screening
of chemicals in soil:
- Soil sample analyses yield 363 different chemicals
found in soil (297 of them were found offsite and 305 were found onsite)
- The maximum concentration was above the respective comparison value
for 27 chemicals found offsite and 49 chemicals found onsite
- There is no comparison
value for 51 of the chemicals (17 offsite and 38 onsite). For example,
bromobenzene does not have a comparison
value.
A comparison value for a similar chemical (for example another halogenated
benzene as a surrogate for bromobenzene) is used when no comparison value
is available, taking into account the toxicity information and weight
of evidence for the chemical of interest and the surrogate chemical.
The surrogate comparison values is used to derive a comparison value
for the chemical of interest.
Kowetha Davidson asked whether the comparison value is the same as the
screening value. Karl Markiewicz responded that the MRL for a chemical
is the comparison value, and the MRL is used to derive the screening
value.
Example chemical-specific maps of the seven-county vicinity depicting
locations of sample results were displayed for the Subcommittee. These
example chemicals included antimony (Sb), arsenic (As), lead (Pb), mercury
(Hg), trichloroethylene (TCE), and thorium (Th). For each chemical, a
map was shown depicting locations of all detections and non-detections
followed by a map depicting only those locations where sample results
exceed the comparison value. This illustrates the result of the screening
process. Next, a determination is made whether each location exceeding
the comparison values is offsite or onsite.
Screening values for these example chemicals in soil are:
- Antimony =
20 ppm
- Arsenic = 0.5 ppm
- Lead = 400 ppm
- Mercury = 20 ppm
- TCE = 1.6 ppm
- Thorium = no screening value
Barbara Sonnenburg asked whether a map is available that depicts all
soil sample locations for all chemicals analyzed. Karl Markiewicz responded
that he does not have that map and added that such a map would appear
as a field of black dots covering the site because thousands of soil
samples have been collected. Barbara Sonnenburg pointed out that the
maps shown seem to reveal a relative lack of soil sample locations in
some portions of the counties shown. Karl Markiewicz responded that some
chemicals are sampled in certain locations more than in other locations.
For example, the TCE sample locations are biased toward the known sources
of TCE at the Oak Ridge site.
Charles Washington asked how the soil screening values relate to TLVs
(threshold limit values). Karl Markiewicz responded that TLVs are standard
occupational exposure values, which are different from the soil screening
comparison values. The sample locations where the result exceeds the
corresponding comparison value/screening value indicate the locations
where a chemical passes through the screening process.
Charles Washington asked why the maps depict more thorium exceeding
the comparison value at Y-12 than at ORNL. Karl Markiewicz responded
that there appears to have been no sampling for thorium at ORNL, and
asked LC Manley whether he had a response that accounted for the presence
of thorium at Y-12 versus not at ORNL. LC Manley commented that, historically,
there was thorium oxide powder at ORNL (X-10).
Handouts of summary statistics for chemical screening in soil and in
sediment were distributed. Those handouts identify the names of all chemicals
detected above their comparison values, offsite and onsite.
Sediment Screening
Summary Statistics
Karl Markiewicz presented a summary of the results of the ATSDR screening
of chemicals in sediment:
- Sediment sample analyses yield 352 different
chemicals found in sediment (334 of them were found offsite and 269
were found onsite)
- The maximum concentration was above the respective
comparison value
for 42 chemicals found offsite and 56 chemicals found onsite
- There is no comparison
value for 34 of the chemicals (18 offsite and 28 onsite).
For each chemical, ATSDR uses the same screening value for soil as for
sediment for ingestion pathway purposes (inadvertent human consumption).
Example chemical-specific maps of the seven-county vicinity depicting
locations of sample results were displayed for the Subcommittee. These
example chemicals included antimony (Sb), arsenic (As), lead (Pb), mercury
(Hg), trichloroethylene (TCE), and thorium (Th). For each chemical, a
map was shown depicting locations of all detections and non-detections
followed by a map depicting only those locations where sample results
exceed the comparison value. A determination is made whether each location
exceeding the comparison values is offsite or onsite.
Charles Washington asked how soil is distinguished from sediment because
surface soil can be washed down stream and become sediment and soil
samples are collected at depths specified by the sampling program.
Karl Markiewicz responded that ATSDR considers material from wetland
and stream bed locations to be sediment and that the depths at which
soil or sediment are sampled are taken as entered into the data base
by the investigators. ATSDR typically uses the sample results from
the top few inches of soil or sediment for calculation of chemical
exposure. If the sampling depth is not specified, the data are sometimes
considered to be from the top few inches unless it is known that the
samples are deeper cores.
Charles Washington added that it is important to sample sediment after
storm events because the heavy water flow and runoff will stir up sediment
(scouring) from deeper layers. Karl Markiewicz acknowledged that for
a given chemical, sediment detection locations are geographically distributed
farther than for soil, due to the greater physical movement of sediment
by erosion.
Parameter Values for Exposure Dose Calculations For chemical screening calculations, initially the maximum value of
each calculation parameter is used (detected chemical concentration,
exposure duration, exposure frequency, and bio-availability). As the
screening process proceeds, the parameter values are refined to be more
realistic. For example, ATSDR will use the 68th percentile of the chemical
concentration as the exposure concentration, which captures one statistical
standard deviation about the mean of the chemical concentration data
set.
For normally distributed data sets, Karl Markiewicz cited the definition
of one standard deviation (1-sigma) as 68% of the data set, two standard
deviations (2-sigma) as 95% of the data set, and three standard deviations
(3-sigma) as 99.7% of the data set. In the environmental field, it is
often accepted that environmental data approximate a lognormal distribution
(few data points at high values and most data points at low values) rather
than a normal distribution. However, ATSDR retains the use of one standard
deviation (1-sigma) assuming a normal distribution in the data set. It
can be argued that lognormal data distributions may be an artifact of
inadequate/unrepresentative sampling. Sampling efforts often are biased
toward the locations associated with higher chemical concentrations.
The exposure patterns of humans are more normally distributed and do
not routinely place people at the locations of highest chemical concentration.
This is the reasoning behind ATSDR’s use of a normal distribution
of the data.
Estimated Exposure Dose Calculations The equation for calculating exposure dose = C x IR x EF x ED/(BW x
AT).
C = chemical concentration (mg/kg soil [ATSDR uses 68th percentile value])
IR = ingestion rate (kg/day for soil)
EF = exposure frequency (days/year)
ED = exposure duration (years)
BW = body weight (default 70 kg for adult, default 10 kg for child)
AT = averaging time (product of EF and ED = days)
AT carcinogen = product of 365 days/year and 70 years = 25,550 days
AT non-carcinogen = product of 365 days/year and ED years = days
Karl Markiewicz presented the results of exposure dose calculations
for arsenic in soil or sediment as examples, using the existing sample
data for soil and sediment concentration. The results of these were presented
on vertical bar graphs (“thermometer graphs”) to show relative
levels of exposure risk. A chemical that passes through the chemical
screening process to the exposure dose calculation stage (public health
implications phase) is examined in this level of detail and even greater
detail. Two thermometer graphs were displayed; one for long term exposure
(greater than 14 days exposure) and one for short term exposure (less
than 14 days exposure). Each graph presents exposure dose in mg/kg/day,
and labels corresponding to various effects are positioned beside the
vertical exposure dose bar. The thermometer graphs are on logarithmic
scale rather than linear scale in order to fit on one page for display.
The thermometer graph presented for ingestion of arsenic included lethal
exposure dose levels, LOAELs in animals (lowest observed adverse effect
level), NOAELs in animals (no observed adverse effect level), the apparent
threshold level for cancer induced in humans, and the ATSDR oral MRL
level. The estimated exposure dose for the site is well below the ATSDR
MRL, meaning that arsenic would not be carried completely through the
health assessment process for soil or sediment.
The thermometer graph presented for ingestion of antimony included lethal
exposure dose levels, LOAELs, NOAELs, and the EPA RfD level. There are
a variety of comparison values available and they span orders of magnitude,
illustrating the variety of safety factors built into them to protect
sensitive sub-population groups.
Karl Markiewicz demonstrated a spreadsheet-based exposure dose calculator
for the Subcommittee to illustrate the effect on the calculated exposure
dose when a parameter value is changed. The parameters (C, IR, EF, ED,
BW, AT) are entered into the spreadsheet and the exposure dose is calculated
(EXCEL spreadsheet). For example, changing the BW from 70 kg to 10 kg
the exposure dose changes proportionately. Karl Markiewicz will leave
this exposure dose calculation spreadsheet CD in the ATSDR Oak Ridge
field office for ORRHES members to work with if they wish (Subcommittee
members, please do not save any changes you make when exiting the spreadsheet).
Charles Washington asked how ATSDR accounts for synergistic effects
of multiple chemicals. Karl Markiewicz responded that the evidence indicates
that for chemicals below health screening levels (NOAEL levels) there
are not synergistic interactions. Thus, ATSDR takes the position that
there is no synergy among chemicals that are below their screening levels.
This is supported by research studies. Charles Washington hypothesized
simultaneous exposure to lead, uranium, and mercury, at levels that are
slightly below their screening doses. Karl Markiewicz responded that
he considers combinations of chemicals that target the same organ or
tissue, which would be the kidney for uranium and mercury exposure (lead
at typical environmental doses does not affect the kidney). He then considers
the combination of uranium and mercury and how they impact the target
tissues, and whether they are below their screening values. Thus, combinations
of chemicals are considered. This is the approach at ATSDR for accounting
for mixtures of chemicals. Kowetha Davidson added that it is inappropriate
to assume synergism (enhanced effect of a chemical by combination with
other chemicals), usually the effect of mixtures is additive, unless
proven otherwise. Charles Washington commented that the absence of synergism
has not been proven by research. Karl Markiewicz offered to provide references
concerning the issue of mixtures of chemicals.
Work Group Sessions (continued)
PUBLIC HEALTH ASSESSMENT WORK GROUP
Bob Craig reported that ATSDR is
about to issue the first Public Health Assessment (PHA), on uranium
releases from Y-12. Bob Craig presented
an overview of the PHA screening process (refer to the Process
Flow Sheet for Providing Input into The Public Health Assessment Process). The Public Health Assessment Work Group (PHAWG) has had a series of
five meetings in which it has been involved in the development of this
PHA. The PHAWG reviewed the references and the work performed by ATSDR
on this PHA. This PHA has been officially transmitted to the Subcommittee
for review. Following incorporation of Subcommittee review comments this
ATSDR PHA will be made available for public review and comment. Following
the public comment this PHA will be issued, by ATSDR, as the final PHA
for uranium releases from Y-12.
The primary authors of this PHA (Paul Charp and Jack Hanley) are not
present in the Subcommittee meeting. Herman Cember joined the Subcommittee
discussion by telephone.
Overview of the draft PHA:
The PHA examines past exposures (1944 to 1990) separate from current
exposures, and evaluates exposure pathways for uranium from Y-12. Past
radiological exposure pathways evaluated include:
- Air pathway
- Surface water pathway
- Soil pathway
Past chemical (non-radiological) exposure pathways evaluated
include:
- Air pathway
- Ingestion pathways (soil, foods, biota)
Task 6 of the Oak Ridge Dose Reconstruction was used as the primary
source of data for past releases of uranium from Y-12. This reliance
on the Dose Reconstruction was agreed to by the Subcommittee previously.
Current exposures are evaluated using data from EPA, Florida A&M
University primarily from the Scarboro community, OREIS data, and TDEC
data. The current radiological and non-radiological exposure pathways
evaluated are the same as the pathways evaluated for past exposures.
ATSDR Conclusions for Past Exposures:
The total lifetime radiation dose to the maximally exposed person from
uranium from Y-12 is 84.5 mrem. This is below the ATSDR MRL 100 mrem/year
screening level and well below the 5000 mrem over 70 years screening
level. All chemical concentrations for inhalation were much less than
the intermediate duration inhalation MRL. All chemical ingestion doses
were less than those for which health effects have been observed. The
conclusion of ATSDR is that there is not a public health concern from
past exposures. This means that although people were exposed, the exposure
is unlikely to cause health effects.
ATSDR Conclusions for Current Exposures:
The inhalation lifetime radiation dose to the maximally exposed person
from uranium from Y-12 is several orders of magnitude below the ATSDR
MRL of 100 mrem/year and below the 5000 mrem over 70 years screening
level. Regarding ingestion, the average uranium surface water concentrations
are well below the EPA MCL (maximum contaminant level) for uranium
and soil concentrations were indistinguishable
from background. The non-radiological air concentrations were several
orders of magnitude below the EPA action level. The non-radiological
exposure
doses from ingestion of uranium in soil were less than the MRL. The conclusion
of ATSDR is that there is not a public health concern from current exposures.
This means that although people were exposed, the exposure is unlikely
to cause health effects.
Overall ATSDR conclusion:
ATSDR concludes that the levels of uranium released from Y-12 in the
past and currently would not result in harmful health effects for adults
or children, and the site is characterized as having “no apparent
public health hazard” from exposure to uranium from Y-12. This
means that people could be or were exposed but the level of exposure
would not likely result in adverse health effects. ATSDR recommends
that the community be informed of the evaluation of uranium releases
from Y-12 and that there is no public health hazard from past and current
exposures. ATSDR will work with ORRHES to determine the best way to
communicate the results of this PHA to the people of the community.
Don Creasia asked how the lung dose from uranium was calculated. Herman
Cember responded that he hasn’t seen the calculations but believes
it to be based on the ICRP 30 3 compartment lung model for the respiratory
tract, which gives the average dose to the lungs as a whole. This is
the standard calculation method, which typically assumes a 1 micron particle
size for conservatism, accounts for the solubility of the inhaled uranium,
estimates fractional deposition of activity, estimates clearance from
each model compartment, and uses the uranium radiation energies to calculate
total radiation dose to the lungs. Herman Cember pointed out that the
ICRP 66 model goes into more detailed calculation (for each portion of
the lung), but in this case the ICRTP 30 model was used.
Charles Washington asked what was used to estimate uranium emissions
for years when records were not kept of the annual uranium emissions
from the entire plant. During those years workers worked three 8-hour
shifts per day, for 40 hours per week. Bob Craig responded that those
uranium emissions are based on the Task 6 Oak Ridge Dose Reconstruction
estimates for 1944 to 1990. Herman Cember commented that he believes
that there were air monitors in town at stations that would measure the
radionuclide concentrations in the air to which people were exposed offsite,
and it is the exposure concentration rather than total emission that
is needed to estimate exposure.
Charles Washington commented that the locations for such monitors must
be placed so that they account for local meteorological conditions and
the effect on transport of the uranium particles in air. Herman Cember
agreed, and stated that he believes those meteorological factors were
taken into account when the air monitoring was performed. Further, Charles
Washington noted that the uranium concentrations measured in the Scarboro
community (the closest community to Y-12) locations are several orders
of magnitude higher than at any other locations outside the plant and
asked whether that factor was considered in the PHA. Herman Cember responded
that although the Scarboro community measurements were the highest, the
concentrations are extremely small (femtocuries per cubic meter) compared
to levels of concern
in air (picocuries per cubic meter).
Charles Washington asked what the long-term effect of this exposure
to small concentrations would be on the community over the 50 to 60 years
of exposure, considering DOE operated multiple sites at over the years
(multiple sources of emission). Bob Craig responded that the PHA document
states that the lifetime effect is the 84.5 mrem from past exposures
presented for the maximally exposed person. Kowetha Davidson asked whether
Charles Washington was implying that emissions from other sources would
have produced higher concentrations in Scarboro than Y-12 would have.
Charles Washington responded that the emissions from all sources would
have impacted the Scarboro community. Herman Cember asked how the air
monitoring data can be used to distinguish between uranium releases from
Y-12 versus uranium releases from the other plants. Tony Malinauskas
acknowledged Herman Cember’s question and pointed out that this
PHA addresses only releases from Y-12. Bob Craig responded that Jack
Hanley and Paul Charp (ATSDR) will be asked Herman Cember’s question:
how does the PHA distinguish only the uranium releases from Y-12 using
the air monitoring data at locations in the community. Charles Washington
added that there is a significant difference between plant operation
at 100 % capacity and operating at 25% to 35% of capacity.
Elmer Akin commented that EPA received an early copy of this PHA document
and EPA will make comments independent of the Subcommittee. The issue
may be brought out that EPA has another way of deriving a “safe
level” of radiation that is different from the ATSDR 100 mrem value
that is in this PHA document. The EPA level is a risk based value which
will be lower than the ATSDR 100 mrem value. Bob Craig added that the
issue of using a dose based versus risk based value will likely come
up in discussions and comments. There is a difference of opinion on which
basis to use to present the results of the PHA.
Charles Washington cautioned the Subcommittee on the wording in the
ATSDR conclusion “…would not result in harmful health effects.” Kowetha
Davidson pointed out that today the ORRHES is considering the PHAWG comments
on the ATSDR PHA, the Subcommittee is not deciding today whether or not
to endorse the PHA and its conclusions and recommendations.
Herman Cember, commenting on how to present the results of the PHA to
the public, urged that the best way to present the results is to compare
to the uranium exposure people are exposed to routinely anyway in the
absence of emissions from the plants. The use of units such as mrem,
femtocurie, picocuries etc. will likely confuse the public and lack meaning.
Bob Craig read the recommendation to the Subcommittee from the PHAWG:
As
part of our review of the ATSDR draft “Public Health Assessment
Y-12 Uranium Releases,” the ORRHES recommends the attached comments
to ATSDR for their consideration and response.
Overview of the PHAWG comments
on the draft PHA: Tony Malinauskas reported on details of the PHAWG comments. The PHAWG
reviewed the draft PHA for 2 weeks and then compiled comments. Two categories
of comments were compiled: editorial comments and issue-related comments.
The PHAWG then discussed its review comments. Skipping the editorial
comments, the technical comments/issues are:
Technical Issues/Comments:
Comment 1:
If the releases of uranium from Y-12 have a greater effect in the Scarboro
community due to Scarboro’s proximity to Y-12, then this serves
as the limiting case. If not, then the title may need to changed to
releases from the DOE facilities (not just Y-12).
Comment 2:
Does the ATSDR’s estimate of the dose include natural background
contribution or is it only the contribution from the Y-12 plant? Barbara
Sonnenburg asked whether uranium contributions from coal plants (Kingston
and Bull Run) are included. Tony Malinauskas responded that the measurements
conducted in Scarboro would include contributions from all sources including
the local coal burning power plants (TVA). Herman Cember commented that
this is a potential contributing source and presumes they impact the
air measurements.
Comments 3, 4, and 6 (similar):
If the impacts on the Scarboro community are safe then the PHA document
should emphasize this strongly because of long standing community concerns
about health impacts.
Comment 5:
The relationship and differences between the MRL and the screening
level should be clarified. Comments 7, 8, and 9 (similar):
The
ATSDR 5000 mrem over a 70 year period and 71.4 mrem/year appear
to be used equivalently in the PHA document
and are used as the MRL. The appropriateness
of these values for use as the MRL has been argued at previous ORRHES
meetings. It has been argued that this MRL is not conservative and not
acceptable
as a screening level. The use of the MRL for radiation exposure needs
to be better defined and justified.
Comment 10:
Appendix C to the PHA document is difficult to understand and needs re-writing
for a layreader.
These PHAWG recommends to the Subcommittee that these
comments be submitted to ATSDR for consideration. ATSDR would be
required to respond to each
of these comments. Barbara Sonnenburg asked whether both editorial and technical comments
are being proposed for submittal to ATSDR. Tony Malinauskas responded
that both the technical comments and the editorial comments from the
PHAWG are to be submitted to ATSDR.
Jeff Hill commented that the ATSDR recommendation in the PHA does not
include a statement that the impacts from plants/releases other than
Y-12 will be considered by ATSDR. The text leaves the question in the
reader’s mind whether or not the combined effect of all releases
will ever be assessed. Tony Malinauskas responded that the first PHAWG
comment asks ATSDR to substantiate the assumption that Scarboro is the
maximally impacted community from uranium from Y-12. Bob Craig commented
that a uranium release PHA will be performed for each plant and that
ATSDR will ultimately consider cumulative releases from the plants.
Elmer Akin revisited the issue of trying to distinguish uranium from
Y-12 from uranium from other sources when measurements are collected
in the Scarboro community. Perhaps the ATSDR approach regarding uranium
is to determine whether uranium in Scarboro is safe (and assumed to be
entirely from Y-12); therefore, uranium levels in all other communities
are safe. Is this the thinking of ATSDR on uranium? Bob Craig responded
that first PHAWG comment on the PHA addresses exactly Elmer Akin’s
question. ATSDR must prove that Scarboro is the most heavily impacted
community from Y-12. Herman Cember asked whether there are air monitoring
data from other communities around the DOE plants and why so many samples
were taken in Scarboro. Bob Craig responded that air monitoring data
in other communities were not nearly as extensive, but there may be some
data. In the technical comments, the PHAWG is asking ATSDR to examine
available data (Scarboro and other community areas) and demonstrate more
clearly either that all of the uranium in the measurements is from Y-12
or that other sources contribute, and demonstrate whether Scarboro is
the most highly impacted community from uranium releases. LC Manley reported
that he has often asked the question “Why were so many more samples
collected in Scarboro than elsewhere and why aren’t other areas
sampled extensively as well?” LC Manley does not know the rationale
behind this sampling bias. Herman Cember suggested that perhaps it was
suspected that Scarboro would likely be the worst case offsite area (most
highly impacted). Tony Malinauskas added that ATSDR used data that were
available to them from other efforts and did not perform additional sampling
of their own for this PHA.
Regarding the bias toward sampling more extensively in Scarboro, Charles
Washington reported that more sampling was performed in Scarboro because
that was the closest community to the property line of the Y-12 manufacturing
plant. In addition, DOE records show that originally the Scarboro community
area was planned as an upscale white community and subsequently that
plan was changed and the community was ear marked to be a minority community
when scientists became aware of the possibility of a catastrophe.
James Lewis commented that Scarboro may have been sampled more extensively
because of all the media attention it always receives as a minority community
that is located close to the plant fence line. Community members specifically
asked EPA to sample in other areas; however, EPA failed to sample elsewhere
and followed the mandate of a single group. James Lewis suggested that
the Subcommittee needs to have the ATSDR authors of the PHA available
to address these issues/comments about the PHA, and the ORRHES should
stop trying to answer these questions themselves and ask the experts
at ATSDR to provide the answers. James Lewis presented a slide of the
ATSDR Process Flow Sheet for Providing Input into the PHA Process to
emphasize the opportunities for the public and non-PHAWG ORRHES members
to provide input into this PHA process through the PHAWG group (five
PHAWG meetings on this PHA). Too few people are taking advantage of attending
these PHAWG meetings. The details of the PHA are discussed in the PHAWG
meetings, which are the best stage in the PHA process to raise issues
and present comments. The proposed technical and editorial comments are
from the PHAWG “pilot review” of the PHA. In addition to
the PHAWG meetings, there will be opportunities to comment and provide
input to the PHA when the public comment period occurs. At that time
ATSDR will make a presentation about the PHA. Today the ORRHES is voting
to approve transmittal of the current (preliminary review) PHAWG comments
to ATSDR. Individuals will not be limited in their ability to make comments
on this PHA after this Subcommittee meeting. James Lewis emphasized the
need to look at and make use of the opportunities built into the process.
Kowetha Davidson reiterated that the vote today will be whether or not
to transmit the existing PHAWG comments on this PHA to ATSDR. The Subcommittee
is not voting today on whether or not to endorse the PHA document. Kowetha
Davidson emphasized that what is most important is getting approval from
the sub-committee members to transmit these comments to ATSDR. She stressed
that it was not up to the Subcommittee to endorse the PHA document. The
comments include each work group member’s comments in either the
technical or editorial comments.
Tony Malinauskas and Herman Cember proposed amending technical comment
1 to ask that ATSDR state in the PHA document that the measurements
in Scarboro represent uranium releases from all sources in the area
and not only releases from Y-12. The PHA document fails to conclusively
distinguish the source of uranium in Scarboro as being from Y-12. Herman
Cember agreed and stated there was no way he saw in the report to distinguish
between or identify the source of uranium release. He did state that
the correlation between atmospheric concentrations and the amount of
release from Y-12 during the period of 1986 to 1995 is good. The graph
looks good and the R2 value is greater than 0.9, which is excellent.
This implies the level of activity that is being measured originated
at Y-12 because it correlates so well with the emissions that came
from Y-12. Herman Cember also noted that he does not know the accuracy
of the emissions estimates. Other than by implication, there is nothing
that really explicitly can identify the origin of the uranium that
is measured in the Scarboro community.
Discussion of the schedule for
the next ORRHES meeting date: Barbara Sonnenburg requested that the Subcommittee consider the schedule
for the next ORRHES meeting, which was previously scheduled for April
1, 2003. La Freta Dalton considered dates for the next ORRHES meeting,
and proposed that the April 1st date is too soon. The ORRHES is currently
also scheduled to meet on June 3rd which is a fixed date because Dr.
Falk plans to attend that meeting. La Freta Dalton proposed Tuesday April
22, 2003 and the Subcommittee concurred with that date for its next meeting.
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