ORRHES Meeting Minutes
April 22, 2003
Agenda Review. In addition to the project update, work group reports, public comment periods and other standard ORRHES agenda items, Dr. Davidson announced that the following topics would be presented and discussed during the meeting:
- Presentation by Dr. Paul Charp and Mr. Jack Hanley on the Public Comment Draft of the ATSDR Public Health Assessment (PHA) on Y-12 Uranium Releases.
- Presentation by Dr. Charp and Mr. Hanley on ATSDR’s minimum risk level (MRL) and cancer comparison values.
- Presentation by Ms. Dhelia Williamson on the health statistics review. This agenda item will be particularly important due to ORRHES’s request for cancer data from the Tennessee Department of Health (TDOH).
Ms. Sonnenburg noted that the ORRHES current action items would soon be reviewed. She requested additional time and asked that this topic be tabled until the “Unfinished Business” agenda item during the evening session. In the interim, she asked the members to thoroughly review the list of current action items in preparation for the discussion.
Correspondence. Dr. Davidson received a copy of a letter from Mr. Norman Mulvenon, Chair of the Local Oversight Committee to Mr. Gerald Boyd, Manager of the Oak Ridge Operations Office. The purpose of the letter was to commend diligent efforts in the community by Dr. Timothy Joseph of the U.S. Department of Energy (DOE). He is extensively involved in various committees and advisory boards related to DOE activities in the Oak Ridge area. Copies of the letter will be distributed to all ORRHES members.
Announcements. The recorder was absent from the meeting due to an unexpected and serious illness in her family. The attendees were asked to state their names and speak clearly into the microphones to ensure all comments were accurately captured and attributed.
Dr. Davidson entertained a motion to approve the previous meeting minutes; the following change was noted for the record. Change the sentence on page 11 to “The detailed presentation addressed the East Tennessee Technical Park (ETTP) ...” A motion to approve the minutes as corrected was properly made and seconded by voting members. There being no abstentions, opposition or further discussion, the March 3, 2003 ORRHES Meeting Minutes were unanimously approved.
Ms. LaFreta Dalton, the Designated Federal Official (DFO), and other ATSDR staff provided a status report of pending action items.
- The Division of Health Education and Promotion should return to
a future ORRHES meeting to discuss Phase II activities of the needs
assessment. Status: ATSDR expects to receive
the document from George Washington University on May 30, 2003. Staff
will provide copies of the draft document to ORRHES. The members
will be given a 30-day review period as requested by ORRHES.
- The peer review status should be specified for any materials provided
to ORRHES. Status: This item is ongoing with
PHA activities and should be noted as addressed rather than pending.
- ATSDR should create an article for local media on the screening process.
Dr. Joseph should include DOE data on declassified chemicals for the
dose reconstruction. Information about ORRHES accomplishments and changes
in the ORRHES process should also be released. This objective may be
achieved in an article by the ORRHES Chair. Status:
This item is to be resolved by the Communications and Outreach Work
Group (COWG) and the PHA Work Group (PHAWG).
- ATSDR should present a review of health effects studies of nuclear
shipyard workers, radiation levels of concern, exposures and health
effects. Status: An agenda item has been scheduled
for this presentation.
- ATSDR should consider the appropriateness of presenting an MRL in
the radiation screening process that is less than the annual background
radiation exposure of an individual in the United States. Status:
An agenda item has been scheduled for this presentation.
- ATSDR should consider and respond to ORRHES’s recommendations
on the draft PHA of Y?12 uranium releases. Status:
This item will be addressed in ATSDR’s next presentation on the
PHA. ATSDR found ORRHES’s comments to be extremely helpful in
refining and clarifying the public comment draft.
- ATSDR should review soil and sediment data from the Bull Run and Kingston steam plants in conjunction with PHAWG. Status: An agenda item has been scheduled for this presentation.
Regarding action item 1, Ms. Sonnenburg suggested that the Health Education Needs Assessment Work Group (HENAWG) attempt to convene a meeting to review the needs assessment after the document is disseminated on May 30, 2003 and before the next ORRHES meeting is convened on June 3, 2003. Regarding action item 3, Mr. Lewis proposed that a column be added to the list of action items and recommendations identifying responsibility for activities. He was unaware that COWG and PHAWG were expected to resolve this issue.
Regarding action item 3, Dr. Cember requested clarification on the “screening process.” Mr. Jack Hanley of ATSDR explained that several detailed presentations on screening of past exposures were made during ORRHES meetings in 2001. ATSDR evaluated screening conducted by TDOH, technical reviewers’ comments on this project, and other activities. Based on this assessment, ATSDR developed a preliminary list of contaminants of concern.
Mr. Hanley recalled that ORRHES took a vote to formally approve ATSDR’s screening process during the February 2002 meeting. Under the new project plan, the screening of past exposures pre- and post-1990 will be documented in an executive summary of a report that will be presented to ORRHES. The data could be placed in local newspapers at that time, but ATSDR is currently focusing on contaminants of concern only. Mr. Hanley offered to summarize the presentations for new members.
Regarding action item 7, Mr. Lewis asked if ATSDR plans to focus on past releases from the Bull Run and Kingston steam plants. Mr. Hanley explained that ATSDR is charged with evaluating ORR releases and potential public health effects. Environmental samples will be taken and a public health decision will be made based on this assessment. Although uranium is released from the Bull Run and Kingston plants, ATSDR is not mandated to examine the proportion of contaminants from these two sources. The PHA will address the concentration of uranium in soil rather than its source.
Ms. Dalton confirmed that outstanding issues or concerns with the action items would be revisited during the “Unfinished Business” agenda item. Dr. Davidson requested that COWG and PHAWG review the list of action items and recommendations to identify which topics are still of interest to ORRHES. For issues that should be removed, COWG and PHAWG were asked to present recommendations to ORRHES for consideration.
Mr. Jerry Pereira, the ORR Project Manager, addressed the following issues in his status report. First, Dr. William Taylor will begin serving in the ATSDR Oak Ridge field office on a full-time basis on May 1, 2003. His expertise in toxicology and community involvement activities will be invaluable to ATSDR and ORRHES. On May 5, 2003, Ms. Melissa Fish will begin a one-year full-time position in the field office as well. She was previously employed in the field office on a temporary basis in the summer and fall of 2002. Her full-time duties will include development of the ORRHES work group meeting minutes, maintenance of the community health concerns database (CHCD), and other clerical and administrative duties.
ATSDR personnel from the Community Involvement Branch and Federal Facilities Branch will continue to staff the field office until the transition is made. Ms. Marilyn Palmer, the ORRHES Committee Management Specialist, will manage the office the week of April 28, 2003. ORRHES members who are interested in visiting the field office should telephone in advance.
Second, the upcoming DOE budget will most likely have a negative impact on all ATSDR activities. After actual figures are given to ATSDR, if needed, Mr. Pereira and other managers will discuss options with the ORRHES chair and work group chairs. Mr. Pereira indicated that he was uncertain of the potential impact the reductions in the budget may have on ORRHES.
Third, materials were distributed to ORRHES outlining the majority of contaminants of concern and ATSDR’s current progress with the activity. If technical staff determine that the project is behind schedule by two or more weeks, ORRHES will be informed of this problem. Technical staff will be asked to maintain an ongoing record of progress based on the overall project plan.
Fourth, Mr. Pereira’s primary role in this effort is to serve as a liaison between ORRHES and ATSDR. He will continue to submit monthly reports to Dr. Henry Falk, the ATSDR Assistant Administrator, about ORRHES’s ongoing and completed activities, budget concerns and other issues. He will also continue to interact with ATSDR technical staff, ORRHES members and the DFO. Mr. Pereira will attempt to resolve problems and meet critical needs within ATSDR and ORRHES by immediately discussing these concerns with Dr. Falk.
Ms. Sonnenburg’s position was that as the ORR Project Manager, Mr. Pereira should be seated at the table with ORRHES. She asked about the relationship between Mr. Pereira’s handouts and a large chart he previously presented illustrating the progress of several activities. She suggested that the handouts be reformatted to show ORRHES’s recommendations and actual outcomes. Mr. Pereira clarified that the large chart reflects the status of the overall project. The handouts are a simpler version of the chart that only show the progress of specific contaminants of concern ATSDR is currently reviewing. In terms of actual outcomes, he confirmed that all activities in the overall project are currently on schedule.
Dr. Craig recalled that iodine-131 was the most comprehensive contaminant of concern and generated the most discussion by ORRHES. He noted that ATSDR was scheduled to reconsider this PHA by April 2003 with an analysis of real-time monitoring data from the early 1950s. Mr. Pereira directed Dr. Craig to review two asterisks on the last page of the handouts for an explanation on iodine-131. At a previous meeting, PHAWG discussed several options to address this issue, such as convening an expert panel. An appropriate strategy is still under discussion.
Mr. Lewis conveyed that PHAWG has historically received meeting minutes of high quality. Because the members are charged with addressing highly technical issues, he was concerned that the quality may decrease with responsibility for the meeting minutes shifting to an administrative/clerical staff member. On another matter, Mr. Lewis underscored the need for Mr. Pereira or other appropriate ATSDR decision-makers to attend PHAWG meetings in person or via conference call and become more involved in these activities. For example, additional PHAWG meetings that were held to address issues for which the members could not agree may have been unnecessary if Mr. Pereira had been present to provide clarification.
Mr. Lewis pointed out that Mr. Pereira’s involvement, input and guidance as the ORR Project Manager could improve PHAWG’s efficiency in problem resolution. To the first comment, Mr. Pereira clarified that ATSDR staff have strongly emphasized the critical importance of the ORRHES work groups to Dr. Falk. The work group chairs, ATSDR staff and Dr. Taylor will review meeting minutes for technical accuracy. However, financial constraints dictate that Ms. Fish be given an opportunity to produce and maintain the work group minutes. To the second comment, Mr. Pereira realized that the ORRHES meeting was behind schedule. He noted Mr. Lewis’s concerns and confirmed that a response would be given during the “Unfinished Business” agenda item.
Mr. Hanley briefly outlined ORRHES’s activities related to the PHA. During the November and December 2002 PHAWG meetings, ATSDR reviewed the list of references and data sources; asked the public to submit any new information; presented the preliminary PHA; and discussed informal comments, concerns and issues raised by the public. The initial data validation version of the PHA was released in January 2003 to ORRHES. PHAWG extensively discussed the document over a series of meetings and obtained comments from other ORRHES members and the public.
PHAWG compiled and presented this feedback to ORRHES; a formal recommendation
was forwarded to ATSDR based on ORRHES’s deliberations during the
March 2003 meeting. Dr. Charp and Mr. Hanley reviewed the comments and
revised the draft PHA based on recommendations to clarify text, provide
explanations and add new material. Comments from ORRHES and the public
played a critical role in significantly improving the document. The current
version is easier to read and more effectively communicates data, but
ATSDR is now requesting additional technical comments from ORRHES. ATSDR
also developed a nine-page briefing document for ORRHES that highlights
key points of the PHA.
The public comment draft was released on April 22, 2003; the 45-day public comment period will officially begin on May 5, 2003 and end on June 20, 2003. Copies of the document would be distributed to ORRHES before the meeting was adjourned. Mr. Hanley explained that the rationale for ATSDR to use the PHA process is fourfold. First, offsite populations that may have been exposed to hazardous substances at levels of health concern are identified. Second, public health implications of the exposure are determined. Third, health concerns of persons in the community are addressed. Fourth, follow-up public health actions or studies to address the exposure are recommended.
The basic components of the PHA process are environmental data, exposure data, health outcome data and community concerns; exposure and health effects evaluations; and public health conclusions and recommendations. All of these factors lead to public health actions. Environmental data used in ATSDR’s PHA of Y-12 uranium releases included past exposures from 1944-1995. The PHA’s major data source for past exposures was the TDOH screening evaluation of uranium releases. The data were submitted for peer review before being included in the document. Current exposures from 1995-present are based on monitoring and sampling data, primarily from Scarboro. ATSDR recently identified data from other sources and included these sites in the PHA as well.
The PHA’s four major data sources for current exposures were the Florida A&M University (FAMU) Scarboro Community Environmental Study conducted in 1998; the 2001 Scarboro Community Sampling Report developed by the U.S. Environmental Protection Agency (EPA); annual monitoring data from the DOE-Oak Ridge Environmental Information System; and monitoring data by TDOH. The previous PHA discussed Y-12 uranium, but the current document discusses uranium without identifying sources. However, ATSDR acknowledges in the PHA that uranium is present from local power plants and other sources.
Scarboro was selected as a reference location in the Oak Ridge dose reconstruction (ORDR) because the offsite population was likely to receive the highest exposures to past releases from the Y-12 plant. This finding was based on air dispersion modeling results collected during the TDOH screening evaluation. The ORDR report stated that “while other potentially exposed communities were considered in the selection process, the reference locations represent residents who lived closest to the ORR facilities and would have received the highest exposures from past uranium releases. Scarboro is the most suitable for screening both a maximally and typically exposed individual.”
Based on these conclusions, ATSDR determined that exposures are not likely to be present in other Oak Ridge communities if no problems are detected in Scarboro. Results in the ORDR report regarding exposures to Scarboro residents are also applicable to other residents living near the Y-12 plant. With respect to potential exposure pathways, ATSDR evaluated air, water, soil, biota, vegetables and fish.
Another important data source for the PHA on Y-12 uranium releases was community concerns. ATSDR compiled, tracked and maintained >1,800 concerns in the comprehensive CHCD developed for ORR. Community concerns about uranium, other contaminants, diseases and specific geographic areas around the Y-12 plant were extracted from CHCD and are addressed in the PHA. Data input into CHCD were submitted to ATSDR from a variety of sources:
- ORRHES and PHAWG meetings from 2000-present.
- The “Save Our Cumberland Mountain” letter in 2001.
- The ORR Public Health Working Group sponsored by ATSDR in 1999.
- The door-to-door Scarboro Community Assessment Report developed by the Joint Center for Political and Economic Studies in 1999.
- Concerns about the Scarboro environment collected by the community from 1997-1999.
- The CDC/TDOH Scarboro Community Health Survey conducted in 1998.
- The Scarboro residents’ letter written to the Oak Ridger in 1998.
To better inform ORRHES about ATSDR’s extensive efforts to evaluate, consider and include all pathways and community concerns in the PHA, Mr. Hanley played a videotape of a Good Morning America broadcast that focused on issues related to the Y-12 plant. Key concerns ATSDR gathered from diverse sources and evaluated for the PHA included play in the East Fork Poplar Creek (EFPC) flood plain soil and water; contact with Scarboro soil and water; inhalation of dust or particles containing uranium from the Y-12, Bull Run and Kingston plants or other sources in the area; and consumption of fish from EFPC, vegetables grown in the area, and meat or milk from cows raised in the EFPC flood plain.
In terms of health outcome data, ATSDR relied on the 1998 health investigation of the Scarboro community. CDC and TDOH conducted the actual study, while EPA and FAMU performed sampling. These activities were conducted in response to the Good Morning America broadcast and other media articles. Based on door-to-door survey results, the agencies clinically examined ~20 children who appeared to be healthy with no problems requiring urgent management. The clinical examinations did not indicate unusual morbidity patterns among Scarboro children. Illnesses that were detected were not found to be atypical or more severe than those found in other communities.
Dr. Charp discussed the PHA of Y-12 uranium releases from the perspective of modeling data, concentrations, doses, exposure pathways, and the comparison of doses to ATSDR’s screening values. For its toxicological profile, ATSDR established a uranium MRL at a value of 0.008 mg/m3 of air. The MRL is defined as the lowest baseline figure for which non-cancerous adverse health effects are not expected to occur. Based on 1944-1995 data from the ORDR Task 6 Report, average annual air concentrations of total uranium in Scarboro were estimated at ~1,000 times lower than the ATSDR MRL. This dose is from the intake of chemicals and would primarily affect the kidney.
No average annual doses of uranium from soil and surface water pathways were found at the lowest observed adverse effect level (LOAEL) of 0.06 mg/kg/body weight/day based on 1994-1995 data from the ORDR Task 6 Report. Based on this finding, ATSDR toxicologists and external peer reviewers developed a uranium MRL for an ingestion intake of 0.002 mg/kg/body weight/day. EFPC flood plain soils and water were the basis of this chemical risk exposure. ATSDR also used the ORDR Task 6 Report to estimate the chemical dose to several persons who may have ingested this material, including an adult male and female and children 6 and 12 years of age.
During the time period from 1952-1973, most of the study population was above an MRL for adverse kidney effects from ingestion of contaminated soils and water from the EFPC flood plain. These persons were also above the ATSDR MRL from 1944-1947. However, none of these intakes were above the LOAEL at any point in time from 1944-1995. Total past uranium radiation doses to the Scarboro community were calculated in the ORDR Task 6 report. The 52-year period of time in which persons could have been exposed to uranium released from the facility was estimated to be 1944-1996. Some values were multiplied by 52 for the total 52-year time period; the results showed a dose of ~84 mrem/year.
ATSDR developed a similar calculation, but divided 70 by 52 to examine doses for a 70-year period. The results showed a dose of ~155 mrem/year to the entire body from uranium ingestion based on the sum of doses from air, surface water and soil exposure pathways. The 155 mrem/year dose is slightly above the regulation for public exposure of 100 mrem/year established by the Nuclear Regulatory Commission. The ORDR Task 6 Report showed the following results. Of the total radiation dose from surface water, 59% was from EFPC fish consumption; 5% was from milk consumption from dairy cows drinking EFPC water; and <1% was from EFPC water by immersion, incidental ingestion or consumption of meat from livestock drinking EFPC water.
Of the total radiation dose from soil, 73% was from consumption of vegetables grown in contaminated soil and 5% was from inhalation of resuspended dust. When the ORDR Task 6 Report was released in 1996, the Scarboro community expressed great concern with the FAMU sampling activity. As a result, EPA collected additional samples in 1998. In a comparison of these results, the EPA and Scarboro findings are essentially identical for both uranium-235/238. FAMU did not sample for uranium-234. The amount of uranium-235/238 in the flood plain was found to be ~20 times higher than levels detected in the Scarboro community by EPA and FAMU.
This finding indicates flood plain soils are contaminated downstream and Scarboro soils have lower levels. If flood plain soils are used as a surrogate for Scarboro soils, doses could perhaps be an order of magnitude to ten times higher than levels detected by EPA and FAMU. To evaluate total uranium concentrations in air, sampling locations were established at several locations: Bear Creek Road/Scarboro Road intersection, Bull Run Steam Plant, Fort Loudon, Freel’s Bend, Kingston Steam Plant, Morgan County at Norris Dam, Pine Ridge, the Turnpike, Tulane Road and Scarboro.
All sampling locations were found to be ~1 million times lower than the ATSDR uranium MRL of 0.008 mg/m3 for air inhalation. Scarboro was found to be slightly higher than background locations, but the source of concentrations in this area was not identified. Figures from the FAMU and EPA studies were used to determine the uranium dose following ingestion of Scarboro soils. The EPA Exposure Factor Handbook was used as the basis to select food ingestion rates from the Southeastern part of the country and increase the body weight from 70 kg to 80 kg. Doses for an adult male and female and children 6 and 12 years of age were found to be ~140 lower than the uranium MRL of 2 mg/kg/body weight/day for soil ingestion.
In evaluating total uranium dose following ingestion of vegetables grown on- and offsite of ORR, ATSDR learned that DOE planted vegetable gardens co-located with sampling sites at some air monitoring stations. Comparisons were made of food grown in a private garden in Scarboro, onsite at the Y-12 plant, in Scarboro, at Norris Dam and in Claxton near the Bull Run Steam Plant. Data showed that the total uranium dose at all locations was ~100 times lower than the ATSDR MRL. Scarboro doses were found to be slightly lower than the Y-12 plant and fairly similar to Claxton and the DOE air monitoring location.
For total uranium concentrations in EFPC and Bear Creek, comparisons were made to the ATSDR Environmental Media Evaluation Guide (EMEG) of 20 mg/L and the EPA maximum contaminant level (MCL) for uranium of 20 mg/L. However, the EPA MCL will be slightly modified in December 2003. Mean concentrations were found to be 0.197 mg/L in offsite Scarboro drainage ditches; 12.8 mg/L at a Lower EFPC offsite location; 8.4 mg/L at a Lower EFPC onsite location after joining with Bear Creek; 33.5 mg/L at an Upper EFPC onsite location; and 159 mg/L at a Bear Creek onsite location.
To estimate a current whole-body radiation dose to the Scarboro community, ATSDR summed an air inhalation rate based on air monitoring data; soil ingestion by a Scarboro resident 1 year of age; and vegetable consumption from a private garden near Scarboro consistent with a rate in the Southeast. The whole-body radiation dose was ~0.2 mrem; the organ dose to bone was ~21 mrem. This calculation equates to <1 mrem/radiation over 70 years. To determine whether Scarboro soils are different than typical Oak Ridge soils, ATSDR analyzed the percent of uranium per gram of soil using Scarboro soil samples collected by both EPA and FAMU. However, ATSDR acknowledged uncertainties with these data.
Uranium-238 accounts for ~99.3% of uranium found in nature; uranium-234/235 are responsible for the remainder. A comparison of all Scarboro soils collected by EPA and FAMU showed essentially no differences in background concentrations. The average levels of uranium-235 levels appeared to be elevated, but no statistically significant differences were seen between Scarboro soils and natural concentrations when data were adjusted for uncertainties. However, uranium-235 appeared to be slightly enriched in the Chattanooga-Shell area. Statistically significant differences between background concentrations in Scarboro and uranium-234 levels were not seen as well.
ATSDR also made a comparison between uranium in Scarboro soils and naturally occurring uranium using a ratio method. Uranium-234 and -235 concentrations were divided by uranium-238. The values showed 1.16 for uranium-234 and 0.096 for uranium-235. Although typical concentrations in Scarboro are 0.97 for uranium-234 and 0.047 for uranium-235, no statistically significant differences were seen when data were adjusted for uncertainties in the measurements. Overall, ATSDR’s evaluation of past and current uranium exposures to offsite populations concluded that no public health concerns exist from air, surface water or soil exposure pathways.
In response to Dr. Cember, Mr. Hanley confirmed that Y-12 uranium releases are documented; modeling data are based on outcomes after uranium was released; and actual amounts of releases are known. Ms. Kaplan pointed out that in addition to modeling data, assumptions were also made to select Scarboro as the reference location. She inquired about methodologies used to ensure these assumptions were correct because inaccurate hypotheses have been generated in the past. For example, Tennessee Valley Authority stacks were initially believed to contribute the greatest impact to nearby communities, but effects were later detected at sites farther than the local area. Ms. Kaplan asked to review data used to support assumptions for the Scarboro location.
Mr. Hanley committed to reviewing the assumptions, discussing this issue with TDOH technical staff who conducted the dose reconstruction, and sharing the information with ORRHES. He conveyed that TDOH used EPA’s standard and conservative model in the screening analysis. During this review, Ms. Adkins asked Mr. Hanley to also determine whether TDOH considered erratic patterns of underground crevices and various formations of limestone slabs. She was interested in whether Scarboro or other communities shared a limestone slab with a dumping site or burial ground. These issues may have left some communities with contaminated groundwater.
Mr. Hanley explained that the uranium species used by the Y-12 plant typically did not travel far in groundwater. However, ATSDR plans to evaluate groundwater at the reservation in a separate and specific PHA. In the Y-12 uranium PHA, washed-off uranium from the bone yard, burn yard and S-3 Ponds that migrated into Bear Creek surface water was considered, evaluated and included. Mr. Hanley raised the possibility of adding a section in the PHA to clarify these issues.
Several ORRHES members expressed concern with the 1998 CDC/TDOH health investigation in the Scarboro community. Ms. Adkins questioned whether Scarboro children were examined prior to 1998. She raised this issue because many residents who lived in her previous community during the 1950s-1960s have died. If a study was conducted at this site now, no health effects would be detected. Ms. Adkins mentioned that missing information on historical exposures and deaths may cause data gaps in the PHA.
Dr. Craig inquired about the 16 children who resided on Benedict Avenue and were found to be ill. Mr. Lewis reported that all of the children’s illnesses identified in the study were previously diagnosed by their pediatricians. At the time of the investigation, the ill children were already being treated for asthma or other respiratory effects. He pointed out that the CDC/TDOH study validated efforts in the community. Mr. Washington conveyed that the health investigation did not acknowledge the number of ill children who were tested at the University of Tennessee Hospital. His position was that the study results were not justified since this information was excluded.
Dr. Akin noted that the CDC/TDOH investigation was flawed because the investigation was conducted at another point in time when disease rates may have been different. Moreover, the sample size of 20 children was extremely small and would not have shown statistically significant results in the reference population. Mr. Hanley responded to ORRHES’s concerns about the CDC/TDOH health study of the Scarboro community as follows. Illnesses detected in children were not found to be more severe than any other community. The study only focused on children in Scarboro at that time because the community was concerned with this particular period. Potential exposures, impacted populations, doses and health outcomes from a historical perspective were addressed in the ORDR. Past exposures from this data source were included in the PHA. Mr. Hanley committed to distributing the CDC/TDOH study at the next meeting for ORRHES’s review.
Mr. Gartseff asked about ATSDR’s process to identify data gaps in potentially exposed communities or individuals. Mr. Hanley responded that ATSDR attempts to identify data gaps with its two databases for current exposures and community concerns. Moreover, the PHA Guidance Manual outlines a standard protocol each health assessor must follow to locate data. However, ORRHES should feel free to inform ATSDR about additional issues that should be addressed in the final PHA. Data gaps that cannot be filled will be noted in the document. ATSDR will also consult with DOE, EPA and TDOH about appropriate steps that should be taken if a determination cannot be made. Mr. Hanley acknowledged that ATSDR has released “indeterminate” PHAs due to data gaps.
In response to Dr. Cember, Dr. Charp was not aware of any autopsy data on the amount of uranium found in various organs of Scarboro residents and the use of this information to validate intake estimates and doses. Ms. Kaplan requested additional details on uncertainties associated with estimated average annual air concentrations of total uranium in Scarboro monitored from 1944-1995. These uncertainties would impact all of ATSDR’s data and may decrease the distance between concentrations and the MRL. Dr. Charp agreed with this observation because uncertainties can fluctuate to a great degree. Most notably, detection methods applied in 1999 were significantly different than those currently used. He committed to obtaining more detailed information about the uncertainties from the ORDR Task 6 Report or ChemRisk, the company that analyzed the data.
Dr. Charp explained that in some instances, ChemRisk estimates were five times higher than DOE releases. However, levels would still be 10 times below the MRL even if the uncertainties were found to increase concentrations by an order of magnitude. Mr. Hanley added that an appendix in the ATSDR PHA points out the ChemRisk calculations of air concentrations were overestimated based on modeling used. Ms. Adkins noticed that some communities may be more impacted by uranium releases than Scarboro if natural ridge pathways, underground limestone slab formations, official and unofficial burial sites of toxins, and the incidence of illness are collectively considered and analyzed.
To address this issue, Dr. Charp confirmed that ATSDR can apply groundwater monitoring data to geo-locate these points. After all data are collected, efforts can also be made to overlay groundwater locations with air monitoring stations to identify a correlation with illnesses. He acknowledged that communities in the northeast or southwest end of Bear Creek Valley may have been more adversely impacted. To account for uncertainties, Dr. Cember inquired if values were multiplied by a factor of ~3-10 when LOAELs were adjusted to the MRL. Dr. Charp replied that LOAELs were divided by uncertainty values to account for variations in species, particularly when extrapolating data from animals to humans.