Health Consultation - Proposed Mercury Clean-Up Level For The East Fork Poplar Creek Flood Plain Soil, U.S. Doe Oak Ridge Reservation, Oak Ridge, Anderson County, Tennessee : Oak Ridge Reservation Environmental Health Archives (Orreha) Document Number Xvii.


Oak Ridge Reservation
Environmental Health Archives
Current as of 10FEB99
Compiled by
Captain John R. Stockwell, M.D., M.P.H.
U.S. Public Health Service
Health Consultation — Proposed Mercury Clean-Up
Level for the East Fork Poplar Creek Flood Plain
soil, U.S. DOE Oak Ridge Reservation — Oak Ridge,
Anderson County, Tennessee
c. 01FEB95
Oak Ridge Reservation
Environmental Health Archives
(ORREHA)
Document Number

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Oak Ridge-Pollution
Health Consultation. Proposed mercury
clean-up of the East Fork Poplar Creek
flood plain soil. Feb. 1995.
Health Consultation
Public Comment Release
PROPOSED MERCURY CLEAN-UP LEVEL FOR THE
EAST FORK POPLAR CREEK FLOOD PLAIN SOIL
US DOE OAK RIDGE RESERVATION
OAK RIDGE, ANDERSON COUNTY, TENNESSEE
FEBRUARY 1995
US EPA REGION 4 LIBRARY
AFC-TOWER 9™ FLOOR
61 FORSYTH STREET SW
ATLANTA, GA. 30303
Comment Period Ends: March 17, 1995
OAK RIDGE ROOM
OAK RIDGE PUBLIC LIBRARY
37530
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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
Agency for Toxic Substances and Disease Registry-
Office of Regional Operations

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Health Consultation: A Note of Explanation
An ATSDR health consultation is a verbal or written response from ATSDR to a specific
request for information about health risks related to a specific site, a chemical release,
or the presence of hazardous material. In order to prevent or mitigate exposures, a
consultation may lead to specific actions, such as restricting use of or replacing water
supplies; intensifying environmental sampling; restricting site access; or removing the
contaminated material. In addition, consultations may recommend additional public
health actions, such as conducting health surveillance activities to evaluate exposure or
trends in adverse health outcomes; conducting biological indicators of exposure studies
to assess exposure; and providing health education for health care providers and
community members.
The Public Comment Period is an opportunity for the general public to comment on
Agency findings or proposed activiites for this written consultation. The purposes of the
comment period are to 1) provide the public, particularly the community associated with
a site, the opportunity to comment on the public health findings, 2) evaluate whether the
community health concerns have been adequately addressed, and 3) provide ATSDR
with additional information.
The conclusions and recommendations presented in this health consultation are the
result of site specific analyses and are not to be cited or quoted for other evaluations or

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Oak Ridge-Pollution
Proposed Mercury clean up for East Fork
Poplar Creek flood plain soil. Feb. 95.
Health Consultation
OAK RIDGE ROOM
OAK RIDGE PUBLIC LIBRARY
0?.k F-iclge, Tennessee 37:00
US DOE OAK RIDGE RESERVATION
(PROPOSED MERCURY CLEAN-UP LEVEL for the
EAST FORK POPLAR CREEK FLOOD PLAIN SOIL)
OAK RIDGE, ANDERSON COUNTY, TENNESSEE
CERCLIS NO. TN1890090003
JANUARY 1996
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
Agency for Toxic Substances and Disease Registry
Office of Regional Operations

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Health Consultation: A Note of Explanation
An ATSDR health consultation is a verbal or written response from ATSDR to a specific
request for information about health risks related to a specific site, a chemical release,
or the presence of hazardous material. In order to prevent or mitigate exposures, a
consultation may lead to specific actions, such as restricting use of or replacing water
supplies; intensifying environmental sampling; restricting site access; or removing the
contaminated material.
In addition, consultations may recommend additional public health actions, such as
conducting health surveillance activities to evaluate exposure or trends in adverse health
outcomes; conducting biological indicators of exposure studies to assess exposure; and
providing health education for health care providers and community members.
This document has previously been released for a 30 day public comment period.
Subsequent to the public comment period, ATSDR addressed all public comments and
revised or appended the document as appropriate. The health consultation has now been
reissued. This concludes the health consultation process for this site, unless additional
information is obtained by ATSDR which, in the Agency's opinion, indicates a need to revise

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HEALTH CONSULTATION
US DOE OAK RIDGE RESERVATION
(PROPOSED MERCURY CLEAN-UP LEVEL for the
EAST FORK POPLAR CREEK FLOOD PLAIN SOIL)
OAK RIDGE, ANDERSON COUNTY, TENNESSEE
CERCLIS NO. TN1890090003
Prepared by
Agency for Toxic Substances and Disease Registry

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STATEMENT OF ISSUES
In February 1995, the Agency for Toxic Substances and Disease Registry (ATSDR) prepared
a health consultation on the U. S. Department of Energy's (DOE) proposed 180 mg/kg
mercury clean-up level for the East Fork Poplar Creek flood plain soil ATSDR concluded
that the 180 mg/kg mercury clean-up level for the flood plain soil would be protective of
public health (1).
As a result of public comments on DOE's proposed plan for the East Fork Poplar Creek,
DOE revisited the assumptions used to develop the 180 mg/kg mercury clean-up level. Based
on this review, DOE decided to adopt a new clean-up level of 400 mg/kg mercury for the
flood plain soil (2).
As requested by members of the public and the City of Oak Ridge, ATSDR has evaluated the
public health impact of the new clean-up level of400 mg/kg mercury in soil. We analyzed
the clean-up level using a worst case exposure scenario and the most Ukely exposure scenario
of a small child in a residential setting (similar to those used in the February 1995 health
consultation).
We conclude that the 400 mg/kg clean-up level of mercury in the flood plain soil will be
protective of public health.

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BACKGROUND
ATSDR's February 1995 Health Consultation
The February 1995, ATSDR health consultation evaluated the public health impact of DOE's
proposed clean-up level of 180 mg/kg mercury for the East Fork Poplar Creek flood plain
soil. To demonstrate the protectiveness of the proposed level, ATSDR analyzed the 180
mg/kg level using a worst case scenario. ATSDR concluded that the 180 mg/kg clean-up
level for the flood plain would pose no health threat to children or adults (1). ATSDR
recommended that until a permanent remedial action is implemented DOE should advise the
public of, and restrict public access to, flood plain soil that is contaminated with mercury
concentrations exceeding the 180 mg/kg clean-up level (1).
DOE's Reevaluation of Clean-up Level
In response to public comments received by DOE on the February 1995 Proposed Plan for
East Fork Poplar Creek, DOE reevaluated the bioavailability factor (i.e., 30 percent
bioavailability) used to develop 180 mg/kg mercury clean-up level (2). Based on this
reevaluation, DOE decided to use a lower bioavailability factor (i.e., 10% bioavailability)
which results in a 400 mg/kg mercury clean-up level for the flood plain soil (2). The DOE,
U. S. Environmental Protection Agency (EPA), and the Tennessee Department of
Environment and Conservation (TDEC) have selected a East Fork Poplar Creek remedial
action which excavates and disposes of flood plain soil contaminated with mercury levels
exceeding the 400 mg/kg clean-up level (2).
Request for Health Consultation
Based on comments made by the public during DOE's February 1995 public meeting and a
request to DOE by the City of Oak Ridge Environmental Quality Advisory Board (EQAB)
that ATSDR conduct another independent evaluation of the new clean-up level, ATSDR
evaluated the public health impact of the 400 mg/kg mercury clean-up level for flood plain
soil. We analyzed the clean-up level using a worst case scenario and a likely exposure
scenario of children in a residential setting.
DISCUSSION
Exposure Scenarios
In order to evaluate whether the new clean-up level is protective, we considered residential
land use scenarios which provide the maximum opportunity for exposure to the mercury in
the East Fork Poplar Creek flood plain soil (1). These exposure scenarios use the most
sensitive population (young children) exposed to the most highly absorbable form of
inorganic mercury (mercuric chloride) by the most probable exposure route (ingestion) of

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swallowing dust and dirt. For additional information on our assumptions refer to the
attached February 1995 ATSDR health consultation.
Worst Case Scenario
This scenario is the same worst case scenario described in the February 1995 ATSDR health
consultation on the 180 mg/kg clean-up level (1). It assumes young children are exposed
every day to East Fork Poplar Creek flood plain soil containing 400 mg/kg of mercury (1).
Using the worst case scenario we estimate a child would receive 0.002 mg/kg/day of
mercury during the early years of life (milligrams of mercury for every kilogram of the
child's body weight every day) if the child swallowed daily a small amount of soil containing
400 mg/kg mercuric chloride. This calculated oral exposure dose of 0.002 mg/kg/day for
children is approximately 115 times less than the no-observed-adverse-effect level (NO AFT)
of 0.23 mg/kg/day for intermediate exposure (more than fourteen days but less than one
year) to mercuric chloride, 230 times less than the intermediate lowest-observed-adverse
effect level (LOAEL) of 0.46 mg/kg/day, and 950 times less than the LOAEL of 1.9
mg/kg/day for chronic exposure (more than one year) to mercuric chloride (3,4). Thus, our
estimated exposure dose for the worst case scenario is much lower than the LOAELs and
NOAEL. For additional information on the LOAELs and NOAEL for mercuric chloride
refer to the February 1995 ATSDR health consultation.
Likely Exposure Scenario
In response to public comments on the use of a worst case scenario in the February 1995
ATSDR health consultation, we have also evaluated the 400 mg/kg mercury clean-up level
using a more realistic exposure scenario. This likely exposure scenario for the flood plain
assumes young children are exposed to the flood plain soil five days a week for 36 weeks of
the year. ATSDR bases this assumption on the use of, and accessibility to the flood plain
and on the climate for the Oak Ridge area.
Based on this more likely residential exposure scenario, we calculated an oral exposure dose
of 0.001 mg/kg/day for a young child. This estimated oral exposure dose for the early years
of a child's life assumes a mercuric chloride concentration of 400 mg/kg in surface soil, a
soil ingestion rate of 100 mg soil per day, an exposure factor of 0.49 for a child in contact
with contaminated soil 5 days a week for 36 week a year, and a body weight of 16 kg for a
child 1 through 6 years old. In this exposure scenario, our calculated oral exposure dose of
0.001 mg/kg/day for children is approximately 230 times less than the intermediate NOAEL
of 0.23 mg/kg/day, 460 times less than the intermediate LOAEL of 0.46 mg/kg/day, and
1,900 times less than the chronic LOAEL of 1.9 mg/kg/day (3,4). Once again, the
calculated exposure dose is much lower than the LOAELs and NOAEL for mercuric
chloride.

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As described in the February 1995 ATSDR health consultation, it is important to be cautious
when generalizing from animal data. However, we are confident that the clean-up level of
400 mg/kg of mercury in the flood plain soil will pose no health threat because the estimated
oral exposure dose is so much lower (2 to 3 orders of magnitude) than the relevant NOAEL
and LOAELs (1). In addition, our assumptions, even in the more likely exposure scenario,
provide a substantial margin of safety in assessing the health hazard to the community.
CONCLUSION
After evaluating the new East Fork Poplar Creek flood plain soil clean-up level of 400 mg/kg
mercury using a worst case exposure scenario and a likely exposure scenario, we conclude
that this level is protective of public health. For both exposure scenarios, estimated oral
exposure doses of mercury are orders of magnitude lower than LOAELs and NO AFT, for
inorganic mercury ingestion developed from U. S. Public Health Service studies. Therefore,
we believe that the East Fork Poplar Creek flood plain soil clean-up level of 400 mg/kg
mercury will be protective of public health and will pose no health threat to children or
adults.
RECOMMENDATION
Implement the recommendations in the February 1995 ATSDR health consultation using the
new clean-up level of 400 mg/kg mercury in soil.

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PREPARERS OF REPORT
Jack E. Hanley, M.P.H.
Environmental Health Scientist
Energy Section B
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation
REVIEWERS OF REPORT
Heather Tosteson, Ph.D.
Writer
Program Evaluation, Records & Information Services Branch
Division of Health Assessment and Consultation
Burt Cooper
Section Chief
Energy Section B
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation

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REFERENCE
1.	Agency for Toxic Substances and Disease Registry. Health Consultation: proposed
Mercury Clean-up Level for the East Fork Poplar Creek Flood Plain Soil, Oak Ridge,
Tennessee. Atlanta, GA: Agency for Toxic Substances and Disease Registry,
February 1995.
2.	U. S. Department of Energy. Record of Decision for the East Fork Poplar Creek,
DOE/OR/02-1370&D1. Oak Ridge, Tennessee: U. S. Department of Energy, May
1995.
3.	Agency for Toxic Substances and Disease Registry. Toxicological Profile for
Mercury. Atlanta: ATSDR, May 1994; DHHS publication no. ATSDR/TP-93/10.
4.	National Toxicology Program. 1983. Toxicology and carcinogenesis studies of
mercuric chloride (CAS no. 7487-94-7) in F344/N rats and B6C3F1 mice (gavage
studies) as modified based on peer review). National Toxicology Program, U.S.
Department of Health and Human Services, Public Health Service, National Institutes
of Health, Research Triangle Park, NC. NTP TR 408. NIH publication no. 91-3139.

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Health Consultation
Public Comment Release
PROPOSED MERCURY CLEAN-UP LEVEL FOR TEE
EAST FORK POPLAR CREEK FLOOD PLAIN SOIL
US DOE OAK RIDGE RESERVATION
OAK RIDGE, ANDERSON COUNTY, TENNESSEE
FEBRUARY 1995
Comment Period Ends: March 17. 1995
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
Agency for Toxic Substances and Disease Registry
Office of Regional Operations

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HEALTH CONSULTATION
PROPOSED MERCURY CLEAN-UP LEVEL FOR THE
EAST FORK POPLAR CREEK FLOOD PLAIN SOIL
US DOE OAK RIDGE RESERVATION
OAK RIDGE, ANDERSON COUNTY, TENNESSEE
CERCLIS NO. TN189 009 0003
Prepared by
Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Federal Facilities Assessment Branch.

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STATEMENT OF ISSUES
In April 1993, the Agency for Toxic Substances and Disease Registry (ATSDR) wrote a health
consultation on mercury contamination in the East Fork Poplar Creek flood plain. The
finding of the consultation was that mercury contamination in soil did exist at levels that
could pose a health risk to residents in the area (1).
In January 1994, the U. S. Department of Energy (DOE ) released a report that provided
more sampling data and also suggested a clean-up level of 50 mg/kg mercury in soil (2).
This clean-up level was based on the U. S. Environmental Protection Agency (EPA) reference
dose for mercury and conservative assumptions about the potential exposure pathway and
exposure doses that might occur through that pathway (2).
In June 1994, DOE released an addendum to their original report. They presented
additional sampling data which suggested that the predominant forms of mercury found in the
area were mercuric sulfide and metallic mercury and cited new studies concerning the lower
absorption rates of these forms of inorganic mercury. Based on this new information, DOE
now recommends a higher clean-up level of 180 mg/kg (3).
Some members of the local community have questioned DOE's shift in clean-up levels, and,
in particular, they have questioned DOE's assumptions concerning mercury speciation and
absorption. Because of these concerns, these community members requested a consultation
from ATSDR on whether the modified clean-up level mil be protective of public health.
In order to evaluate whether the new clean-up level will be protective, we analyzed the
proposed level using a worst case scenario that bypasses the areas of scientific debate about
speciation and absorption.
Our finding is that the 180 mg/kg clean-up level will be protective of public health.
Until the East Fork Poplar Creek flood plain is remediated, we continue to recommend the
following interim actions to reduce exposures: 1) post signs and restrict public access to
areas with elevated mercury concentrations and 2) continue the East Fork Poplar Creek fish
advisory.

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BACKGROUND
1993	ATSDR Health Consultation
The 1993 ATSDR health consultation evaluated the existing health threat posed by chemical
releases into the East Fork Poplar Creek flood plain by reviewing limited soil, sediment,
surface water, air, and groundwater summary data from the East Fork Poplar Creek
Remedial Investigation Report Phase IA and summary fish data from the DOE Biological
Monitoring and Abatement Program. ATSDR concluded that mercury in soil and sediment
in some areas along the East Fork Poplar Creek flood plain posed a threat to public health,
especially to children playing in the flood plain (1). ATSDR recommended either advising
the public that soil and sediment in the East Fork Poplar Creek flood plain was contaminated
with mercury or restricting access to areas with elevated concentrations of mercury (1).
1994	DOE Remedial Investigations
In January 1994, DOE released the remedial investigation, which evaluated the extent and
level of contamination in the 100-year East Fork Poplar Creek flood plain and established a
preliminary clean-up level of 50 mg/kg (milligrams per kilogram) or ppm (parts per million)
mercury in the flood plain soil (rounded down from 58 mg/kg) to protect children who might
eat the soil or come in contact with it. The preliminary level was based on the U.S.
Environmental Protection Agency (EPA) guidance, EPA reference dose (RfD) for mercury,
and site-specific exposure assumptions (2).
In June 1994, DOE released an addendum to the remedial investigation, which presented the
results of additional studies of mercury in the East Fork Poplar Creek flood plain soil. In
the addendum DOE stated that several different analytical methods indicated that mercuric
sulfide and metallic mercury are likely to be the dominant inorganic mercury forms present
and that mercuric chloride (the most easily absorbed and the most toxic inorganic form of
mercury) is a minor component of the total mercury in the East Fork Poplar Creek flood
plain soils (3). DOE also stated the weight of evidence supports their hypothesis that these
predominant forms of mercury in the flood plain soil are less soluble, less bioavailable (not
as easily absorbed into the bloodstream), and less toxic than the highly soluble mercuric
chloride used to develop the preliminary clean-up level (3). Based on this evidence, DOE
recommended a higher clean-up level of 180 mg/kg mercury in soil by reducing the
bioavailability factor in their calculations from 100 to 30 percent (3).
Request for Health Consultation
Some local residents are concerned about the new recommended clean-up level. In
particular, they have questioned DOE's assumptions concerning the speciation and
bioavailability of mercury in the flood plain soil. These citizens have asked ATSDR to

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evaluate whether the recommended clean-up value of 180 mg/kg mercury in the East Fork
Poplar Creek flood plain soil will be protective of public health.
To evaluate whether the recommended mercury clean-up level is protective, we bypassed the
areas of scientific debate about speciation and bioavailability of mercury in the flood plain
soil and analyzed the 180 mg/kg mercury clean-up level using a worst case scenario.
WORST CASE SCENARIO
This scenario evaluated young children who live close to East Fork Poplar Creek and play in
the East Fork Poplar Creek flood plain soils during the early years of life. This worst case
exposure scenario was selected because it uses the most sensitive population (young children)
exposed to the most highly absorbable form of inorganic mercury (mercuric chloride and
metallic mercury) by the most probable exposure routes. The most probable route of
exposure to inorganic mercury in soil would be swallowing dust and dirt, and the primary
route of exposure to metallic mercury in soil would be breathing mercury vapors in the air
(4).
Mercury in Soil
We estimated a child would receive 0.001 mg/kg/day of mercury during the early years of
life (milligrams of mercury for every kilogram of the child's body weight everyday) if the
child daily swallowed a small amount of dirt (e.g., from mouthing toys or fingers with dust
on them) containing 180 mg/kg mercuric chloride1. We used mercuric chloride in our
calculations because studies have shown it is highly soluble and more of it will be absorbed
across the stomach and walls of the intestine than other forms of inorganic mercury. To
determine if this "worst case" dose poses a health hazard, we then examined recent U. S.
Public Health Service studies of animals fed mercuric chloride.
Animal studies have been used to define a no-observed-adverse-effect level (NOAEL) of 0.23
mg/kg/day for intermediate exposure (more than fourteen days but less than one year) to
inorganic mercury and a lowest-observed-adverse effect level (LOAEL) of 1.9 mg/kg/day for
chronic exposure (more than one year) to inorganic mercury (4, 5). The NOAEL is the
amount of mercury animals ingested five days a week for six months without any adverse
health effect (4, 5). The LOAEL is the smallest amount of mercury animals ingested over a
lifetime (i.e., five days a week for two years) that produced an adverse health effect (4, 5).
For inorganic mercury, the adverse effects first observed in the animals were minor changes
The estimated oral exposure dose for the worst case scenario assumes a mercury concentration
of 180 mg/kg in soil, a soil ingestion rate of 100 mg soil per day, an exposure factor of 1 for
exposure everyday, and a body weight of 16 kg for children 1 through 6 years old.

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in the kidneys and weight loss. More serious kidney effects were seen at a higher dose of
mercury. Our calculated chronic oral exposure dose of 0.001 mg/kg/day for children is
approximately 1,900 times less than the chronic LOAEL of 1.9 mg/kg/day and 230 times
less than the intermediate NOAEL of 0.23 mg/kg/day. Thus, our estimated chronic oral
exposure dose for the worst case scenario is much lower than the LOAEL and NO AFT.
Mercury in Air
In our evaluation of the danger of inhaling mercury vapor from the flood plain soil, we
considered the air concentrations of mercury vapor that were measured over flood plain areas
with the maximum mercury concentrations in soil. Long-term air monitoring indicates the
concentration of mercury vapor ranged from 0.0000031 to 0.0000124 mg/m3 (milligrams of
mercury per cubic meter of air) in air over soil containing up to 3,000 mg/kg mercury
(milligrams of mercury per kilogram soil) (2). To determine the health hazard of inhaling
mercury vapor, we examined studies of people occupationally exposed to metallic mercury
vapor (the most toxic form for inhalation). A chronic occupational human study was used to
define the lowest-observed-adverse-effect level (LOAEL) of 0.026 mg/m3 for chronic
exposure to mercury vapor in air (4, 6). In that study the adverse effect observed was an
increase in the fine tremors that all people have normally. There is also some indication
from other studies that some memory loss and mild kidney effects may occur at this LOAEL.
The maximum concentration of mercury vapor measured in air over the flood plain
(0.0000124 mg/m3) is 2000 times less than the LOAEL of 0.026 mg/m3 (2, 4, 6). Thus, air
concentrations of mercury vapor over flood plain soil at its present level of contamination are
much lower than the LOAEL. The air concentrations of mercury vapor over soil with only
180 mg/kg mercury will be even lower.
DISCUSSION
Exposure Routes
We have considered a worst-case scenario involving children who are exposed to mercury in
East Fork Poplar Creek flood plain soil at a clean up level of 180 mg/kg of mercury. Our
assumptions provide a substantial margin of safety in assessing the health hazard to the
community.
The residential land use scenario provides the maximum opportunity for chronic exposure to
the mercury in the East Fork Poplar Creek flood plain soil. Young children in the residential
areas have the greatest risk of exposure to mercury because they are likely to have the most
frequent and longest duration exposure to East Fork Poplar Creek soils since they play in the
dirt and engage in frequent hand to mouth activity and often mouth objects.

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The frequency and duration of exposure to East Fork Poplar Creek flood plain soil is likely
to be much less for older children and adults in general and particularly for people who do
not live on the flood plain. Within the commercial, DOE, and recreational (e.g., sportsman
club and golf course) areas, access to the flood plain is either difficult or restricted. Within
the agricultural areas, people intermittently enter the flood plain. Consequently, people
would more probably have infrequent and short-duration exposures to mercury via ingestion
of inorganic mercury in soil or inhalation of mercury vapors in the air.
Ingestion of Mercury From Soil
We believe the proposed clean-up level ofl80mgfkg of mercury in East Fork Poplar Creek
flood plain soil will pose no health threat to children or adults.
Swallowing dirt is the most probable route of exposure to inorganic mercury compounds in
the East Fork Poplar Creek flood plain. The hazard from ingesting inorganic mercury is
primarily based on absoiption into the bloodstream (internal dose). Different forms of
inorganic mercury compounds (mercuric chloride and mercuric sulfide are different "forms"
of mercury) have different absoiption rates. Most of our information on absorption of
inorganic mercury after ingestion is from animal studies that used mercuric chloride.
We do not have any direct measures of the amount of mercury that children would absorb (7,
8). No laboratory studies are available on the percent absorption of inorganic mercury from
the gastrointestinal tract in humans (4). However, we know mercury can be absorbed by this
route because mercury has been detected in humans who have ingested inorganic mercury
compounds (mercuric nitrate, mercuric chloride, mercuric sulfide) (14, 15, 16).
Detailed animal studies indicate absorption of inorganic mercury across the gut is limited and
is influenced by the form of mercury and by an animal's age and diet, as well as its species.
For example, young rats may absorb much more mercury than old mice. Mercuric chloride,
the compound we used for our estimate, is used in many animal studies because it is very
soluble in water and is believed to have the highest absorption rate of inorganic mercury.
The absoiption for mercuric chloride by this route ranges from as little as 1 % to as much as
38% in mice and rats (8, 9, 10). Studies suggest that some forms of mercury, for example
mercuric sulfide, have lower absoiption rates or "bioavailability" through the gut than
mercuric chloride (11, 12, 13, 14). However, the relative bioavailability of mercuric sulfide
versus mercuric chloride has not been specifically studied in animals nor has it been
examined in humans (4). On the other hand we are reasonably certain that absorption is
much lower (approximately 0.1 %) for liquid metallic mercury (4). For this reason,
ingestion of metallic mercuiy is much less hazardous than ingestion of mercuric chloride. In
contrast, metallic mercury is dangerous if its vapor is inhaled, because metallic mercury
vapor is easily absorbed through the lungs (4).

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Both animal and human data indicate that, after absorption into the blood, inorganic mercury
compounds go throughout the body but primarily accumulate in the kidneys (4). In animals,
the kidneys had the highest mercury levels following acute and intermediate oral exposure to
mercuric chloride (11). For mercuric sulfide, higher doses were necessary before
accumulation was noted in the kidneys (11, 13, 14). The accumulation of mercury in the
brain and fetuses following ingestion of inorganic mercury compounds is substantially lower
than in the kidneys because the lipid solubility of inorganic mercury compounds is poor,
which prevents inorganic mercury compounds from crossing the blood-brain and placental
barriers (17). Taken together, these studies have shown that renal toxicity is the most
sensitive end point after ingestion of inorganic mercury.
Basis for Ingestion NOAEL and LOAEL: The no-observed-adverse-effect level (NOAEL)
is a dose of mercury that is based on the highest dose of mercury for which no adverse
health effect has ever been observed in animals. Specifically, the highest NOAEL of 0.23
mg/kg/day for intermediate oral exposure to inorganic mercury is based on rats given
mercuric chloride in an aqueous solution by gavage for five days a week for six months (4,
5). Our calculated worst case oral exposure dose of 0.001 mg/kg/day for children is
approximately 230 times less than this NOAEL.
The lowest-observed-adverse effect level (LOAEL) is also protective because it's based on
the lowest dose where any adverse effect has been observed in the kidneys of animals. The
intermediate LOAEL of 0.46 mg/kg/day (derived from six-month mercuric chloride study) is
based on a sensitive biomarker for the first appearance of renal toxicity, increased kidney
weight (4, 5). The chronic LOAEL of 1.9 mg/kg/day for inorganic mercury is based on
microscopic changes to certain components of the kidney as a result of lifetime exposure
(thickening of glomerular and tubular membranes), changes that are likely to indicate more
serious effects than kidney weight change alone (4, 5). This chronic dose is derived from a
two-year study in rats that were exposed a lifetime (i.e., five days a week for two years) to
mercuric chloride in an aqueous solution by gavage (4, 5). Only male rats experienced an
adverse effect in their kidneys at this dose, female rats did not. Furthermore, although
adverse effects were seen in female mice in the same study at a higher dose (3.7 mg/kg/day),
the effects appeared less severe than in males. Taken together, this and other evidence
suggests that male rats may be particularly sensitive to the effects of mercury exposure. The
calculated chronic oral exposure dose of 0.001 mg/kg/day for children is approximately 460
times less than the intermediate LOAEL of 0.46 mg/kg/day and 1,900 times less than the
chronic LOAEL of 1.9 mg/kg/day.
It is important to be cautious when generalizing from animal data. NOAELs and LOAELs
based on animal data are not human health guidelines per se. There is uncertainty in
extrapolating from them for the following reasons:
1) Rat data may not be directly applicable to humans (e.g., humans may be more
sensitive than rats).

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2) Individuals may have different responses (some humans are likely to be more
sensitive than the average).
3) Using a LOAEL does not give a clear threshold below which adverse effects do not
occur (i.e., we are not sure how much lower than the LOAEL we would have to go
before we would stop seeing the adverse effect entirely) .
However, we are confident that the proposed clean-up level of 180 mg/kg of mercury in the
flood plain soil will pose no health threat because the estimated oral exposure dose is so
much lower (2 to 3 orders of magnitude) than the relevant NOAEL and LOAELs.
We also don't expect adverse effects on other organ systems because the amount of mercury
necessary to cause adverse effects is higher for other organs than it is for the kidneys. For
example, no evidence of neurotoxicity was seen in mice administrated 0.74 to 2.2 mg/kg/day
of mercuric chloride in drinking water for 110 days and 7.4 to 14.8 mg/kg/day for an
additional 400 days (18). Also, no histopathological evidence of brain lesions was observed
in rats receiving doses of mercuric chloride as high as 3.7 mg/kg/day by gavage, five days a
week, for up to two years, or in mice receiving doses as high as 7.4 mg/kg/day by gavage,
five days a week, for up to two years (4, 5).
Finally our worst case ingestion scenario evaluates all the mercury in the East Fork Poplar
Creek flood plain soil as mercuric chloride, which assumes that the bioavailability
(absorption) of mercury in East Fork Poplar Creek soil is equivalent to that of mercuric
chloride in an aqueous solution. This assumption is conservative because the majority of
mercury forms in the soil are likely to be less bioavailable than mercuric chloride in aqueous
solution. This assumption provides an additional margin of safety in assuring that exposure
to East Fork Poplar Creek flood plain soil containing 180 mg/kg inorganic mercury will not
result in adverse kidney effects.
Inhalation of Mercury In Air
We believe air concentrations of mercury vapor over the East Fork Poplar Creek flood plain
soil will pose no health threat if soils are remediated to the proposed clean-up level of 180
mg/kg of mercury.
We predict very little exposure to mercury would take place through inhalation if soils are
cleaned up to 180 mg/kg. However, inhalation is the most toxic route of exposure to
metallic mercury. Therefore, we made conservative assumptions in the worst case scenario
for this exposure route.
The primary route of exposure to metallic mercui^ in soil is inhalation of mercury vapors in
the air. Once mercury vapors are inhaled, absorption into the bloodstream is substantial (4).
Approximately 74-80% of inhaled elemental mercury vapor is retained in human tissue (19,

-------
20). Following inhalation, mercury is distributed throughout the body and accumulates
primarily in the kidney, as it does when ingested. However, the lipophilic nature of metallic
mercury also allows it to readily cross the blood-brain and placental barriers and accumulate
in the brain and fetus (4, 17). Therefore, inhalation is a more toxic route of exposure.
Basis for Inhalation LOAEL: The central nervous system is the most sensitive target organ
in humans following inhalation of metallic mercury vapor. The lowest-observed-adverse
effect level (LOAEL) of 0.026 mg/m3 for chronic inhalation exposure to mercury vapors in
air is based on a study in which a significant increase in the average velocity of naturally
occurring tremors was observed in workers exposed to mercuiy vapors (0.026 mg/m3
average concentration) for an average of 15.3 years (range 1-41 years) (6). The range of
mercury concentration (0.0000031 to 0.0000124 mg/m3) measured in the air over flood plain
soil containing 3,000 mg/kg mercury is over 2,000 times less than the LOAEL of 0.026
mg/m3 (2, 4). Since air concentrations of mercury vapor over soil at 3,000 mg/kg mercury
will be much higher than over soil at 180 mg/kg mercury, we think chronic exposure to
mercury vapor from the East Fork Poplar Creek food plain soil with concentrations of 180
mg/kg mercury will not pose a health threat.
CONCLUSION
We conclude that the proposed soil clean-up level of 180 mg/kg mercury for the East Fork
Poplar Creek flood plain is safe. Our estimated ingestion dose is orders of magnitude lower
than the LOAEL and NOAEL for ingestion developed from U. S. Public Health Service
studies of animals fed mercuric chloride. Also, the measured concentration of mercury
vapors in the air are much lower than the LOAEL for chronic inhalation of mercury vapors.
Consequently we think the 180 mg/kg clean-up level for the East Fork Poplar Creek flood
plain soil will be protective for exposures through ingestion as well as through inhalation.
RECOMMENDATIONS
The following recommendations from ATSDR's previous health consultation should be
implemented or remain in effect:
1. As an interim action, until permanent remedial action is implemented, post signs and
restrict public access to East Fork Poplar Creek flood plain areas where soil and
sediment mercury concentrations exceed the 180 mg/kg clean-up level (1).
2. Continue the East Fork Poplar Creek fish advisory. Ensure that a sufficient number
of signs are posted, especially at the confluence of Poplar Creek, to warn the public
of the presence of contaminated fish in the creek (1).

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PREPARERS OF REPORT
Jack E. Hanley, M.P.H.
Environmental Health Scientist
Energy Section B
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation
William H. Taylor, Ph.D.
Environmental Health Scientist
Energy Section B
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation
REVIEWERS OF REPORT
Heather Tosteson, Ph.D.
Writer
Program Evaluation, Records & Information Services Branch
Division of Health Assessment and Consultation
Richard A. Canady, Ph.D.
Toxicologist
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation

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REFERENCE
Agency for Toxic Substances and Disease Registry. Health Consultation: Y-12
Weapons Plant Chemical Release Into East Fork Poplar Creek, Oak Ridge,
Tennessee. Atlanta, GA: Agency for Toxic Substances and Disease Registry, April
1993.
U. S. Department of Energy. East Fork Poplar Creek-Sewer Line Beltway Remedial
Investigation Report, DOE/OR/02-1119&D2&V1. Oak Ridge, Tennessee: U. S.
Department of Energy, January 1994; Contract Number DE-AC05-910R21950.
U. S. Department of Energy. Addendum to the East Fork Poplar Creek-Sewer Line
Beltway Remedial Investigation Report, DOE/OR/02-1119&D2/A1/R1. Oak Ridge,
Tennessee: U. S. Department of Energy, June 1994; Contract Number DE-AC05-
91OR21950.
Agency for Toxic Substances and Disease Registry. Toxicological Profile for
Mercury. Atlanta: ATSDR, May 1994; DHHS publication no. ATSDR/TP-93/10.
NTP. 1983. Toxicology and carcinogenesis studies of mercuric chloride (CAS no.
7487-94-7) in F344/N rats and B6C3F1 mice (gavage studies) as modified based on
peer review). National Toxicology Program, U.S. Department of Health and Human
Services, Public Health Service, National Institutes of Health, Research Triangle
Park, NC. NTP TR 408. NTH publication no. 91-3139.
Fawer et al. 1983. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
Endo et al. 1990. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
Kostial et al. 1978. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
Clarkson 1971. Cited by: Agency for Toxic Substances and Disease Registry. 1994.
Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994; DHHS
publication no. ATSDR/TP-93/10.
Piotrowski et al. 1992. Cited by: Agency for Toxic Substances and Disease
Registry. 1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May
1994; DHHS publication no. ATSDR/TP-93/10.

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11.	Sin et al. 1983. Cited by: Agency for Toxic Substances and Disease Registry. 1994.
Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994; DHHS
publication no. ATSDR/TP-93/10.
12.	Sin et al. 1990. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
13.	Yeoh et al. 1986. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
14.	Yeoh et al. 1989. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
15.	Suzuki et al. 1992. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
16.	Rahola et al. 1973. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
17.	Clarkson. 1989. Cited by: Agency for Toxic Substances and Disease Registry. 1994.
Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994; DHHS
publication no. ATSDR/TP-93/10.
18.	Ganser et al. 1985. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
19.	Hursh et al. 1976. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
20.	Teisinger et al. 1965. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.

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HEALTH CONSULTATION
PROPOSED MERCURY CLEAN-UP LEVEL FOR THE
EAST FORK POPLAR CREEK FLOOD PLAIN SOIL
US DOE OAK RIDGE RESERVATION
OAK RIDGE, ANDERSON COUNTY, TENNESSEE
CERCLIS NO. TN1890090003
Prepared by
Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Federal Facilities Assessment Branch

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STATEMENT OF ISSUES
In April 1993, the Agency for Toxic Substances and Disease Registry (ATSDR) wrote a health
consultation on mercury contamination in the East Fork Poplar Creek flood plain. The
finding of the consultation was that mercury contamination in soil did exist at levels that
could pose a health risk to residents in the area (1).
In January 1994, the U. S. Department of Energy (DOE ) released a report that provided
more sampling data and also suggested a clean-up level of 50 mg/kg mercury in soil (2).
This clean-up level was based on the U. S. Environmental Protection Agency (EPA) reference
dose for mercury and conservative assumptions about the potential exposure pathway and
exposure doses that might occur through that pathway (2).
In June 1994, DOE released an addendum to their original report. They presented
additional sampling data which suggested that the predominant forms of mercury found in the
area were mercuric sulfide and metallic mercury and cited new studies concerning the lower
absorption rates of these forms of inorganic mercury. Based on this new information, DOE
now recommends a higher clean-up level of 180 mg/kg (3).
Some members of the local community have questioned DOE's shift in clean-up levels, and,
in particular, they have questioned DOE's assumptions concerning mercury speciation and
absorption. Because of these concerns, these community members requested a consultation
from ATSDR on whether the modified clean-up level will be protective of public health.
In order to evaluate whether the new clean-up level will be protective, we analyzed the
proposed level using a worst case scenario that bypasses the areas of scientific debate about
speciation and absorption.
Our finding is that the 180 mg/kg clean-up level will be protective of public health.
Until the East Fork Poplar Creek flood plain is remediated, we continue to recommend the
following interim actions to reduce exposures: 1) post signs and restrict public access to
areas with elevated mercury concentrations and 2) continue the East Fork Poplar Creek fish
advisory.

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BACKGROUND
1993	ATSDR Health Consultation
The 1993 ATSDR health consultation evaluated the existing health threat posed by chemical
releases into the East Fork Poplar Creek flood plain by reviewing limited soil, sediment,
surface water, air, and groundwater summary data from the East Fork Poplar Creek
Remedial Investigation Report Phase IA and summary fish data from the DOE Biological
Monitoring and Abatement Program. ATSDR concluded that mercury in soil and sediment
in some areas along the East Fork Poplar Creek flood plain posed a threat to public health,
especially to children playing in the flood plain (1). ATSDR recommended either advising
the public that soil and sediment in the East Fork Poplar Creek flood plain was contaminated
with mercury or restricting access to areas with elevated concentrations of mercury (1).
1994	DOE Remedial Investigations
In January 1994, DOE released the remedial investigation, which evaluated the extent and
level of contamination in the 100-year East Fork Poplar Creek flood plain and established a
preliminary clean-up level of 50 mg/kg (milligrams per kilogram) or ppm (parts per million)
mercury in the flood plain soil to protect children who might eat the soil or come in contact
with it. The preliminary level was based on the U.S. Environmental Protection Agency
(EPA) guidance, EPA reference dose (RfD) for mercury, and site-specific exposure
assumptions (2).
In June 1994, DOE released an addendum to the remedial investigation, which presented the
results of additional studies of mercury in the East Fork Poplar Creek flood plain soil. In
the addendum DOE stated that several different analytical methods indicated that mercuric
sulfide and metallic mercury are likely to be the dominant inorganic mercury forms present
and that mercuric chloride (the most easily absorbed and the most toxic inorganic form of
mercury) is a minor component of the total mercury in the East Fork Poplar Creek flood
plain soils (3). DOE also stated the weight of evidence supports their hypothesis that these
predominant forms of mercury in the flood plain soil are less soluble, less bioavailable (not
as easily absorbed into the bloodstream), and less toxic than the highly soluble mercuric
chloride used to develop the preliminary clean-up level (3). Based on this evidence, DOE
recommended a higher clean-up level of 180 mg/kg mercury in soil by reducing the
bioavailability factor in their calculations from 100 to 30 percent (3).
Request for Health Consultation
Some local residents are concerned about the new recommended clean-up level. In
particular, they have questioned DOE's assumptions concerning the speciation and
bioavailability of mercury in the flood plain soil. These citizens have asked ATSDR to

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evaluate whether the recommended clean-up value of 180 mg/kg mercury in the East Fork
Poplar Creek flood plain soil will be protective of public health.
To evaluate whether the recommended mercury clean-up level is protective, we bypassed the
areas of scientific debate about speciation and bioavailability of mercury in the flood plain
soil and analyzed the 180 mg/kg mercury clean-up level using a worst case scenario.
WORST CASE SCENARIO
This scenario evaluated children who live close to East Fork Poplar Creek and play in the
East Fork Poplar Creek flood plain soils. This worst case exposure scenario was selected
because it uses the most sensitive population (children) exposed to the most highly absorbable
form of inorganic mercury (mercuric chloride and metallic mercury) by the most probable
exposure routes. The most probable route of exposure to inorganic mercury in soil would be
swallowing dust and dirt, and the primary route of exposure to metallic mercury in soil
would be breathing mercury vapors in the air (4).
Mercury in Soil
We estimated a child would receive 0.001 mg/kg/day of mercury (milligrams of mercury for
every kilogram of the child's body weight everyday) if the child daily swallowed a small
amount of dirt (e.g., from mouthing toys or fingers with dust on them) containing 180 mg/kg
mercuric chloride1. We used mercuric chloride in our calculations because studies have
shown it is highly soluble and more of it will be absorbed across the stomach and walls of
the intestine than other forms of inorganic mercury. To determine if this "worst case" dose
poses a health hazard, we then examined recent U. S. Public Health Service studies of
animals fed mercuric chloride.
Animal studies have been used to define a no-observed-adverse-effect level (NOAEL) of 0.23
mg/kg/day for intermediate exposure (more than fourteen days but less than one year) to
inorganic mercury and a lowest-observed-adverse effect level (TO A FT.) of 1.9 mg/kg/day for
chronic exposure (more than one year) to inorganic mercury (4, 5). The NOAEL is the
amount of mercury animals ingested five days a week for six months without any adverse
health effect (4, 5). The LOAEL is the smallest amount of mercury animals ingested five
days a week for two years that produced an adverse health effect (4, 5). For inorganic
mercury, the adverse effects first observed in the animals were minor changes in the kidneys
and weight loss. More serious kidney effects were seen at a higher dose of mercury. Our
The estimated oral exposure dose for the worst case scenario assumes a mercury concentration
of 180 mg/kg in soil, a soil ingestion rate of 100 mg soil per day, an exposure factor of 1 for
exposure everyday, and a body weight of 16 kg for children 1 through 6 years old.

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calculated chronic oral exposure dose of 0.001 mg/kg/day for children is approximately
1,900 times less than the chronic LOAEL of 1.9 mg/kg/day and 230 times less than the
intermediate NO ART, of 0.23 mg/kg/day. Thus, our estimated chronic oral exposure dose
for the worst case scenario is much lower than the LOAEL and NOAEL.
Mercury in Air
In our evaluation of the danger of inhaling mercury vapor from the flood plain soil, we
considered the air concentrations of mercury vapor that were measured over flood plain areas
with the maximum mercury concentrations in soil. Long-term air monitoring indicates the
concentration of mercury vapor ranged from 0.0000031 to 0.0000124 mg/m3 (milligrams of
mercury per cubic meter of air) Ln air over soil containing up to 3,000 mg/kg mercury
(milligrams of mercury per kilogram soil) (2). To determine the health hazard of inhaling
mercury vapor, we examined studies of people occupationally exposed to metallic mercury
vapor (the most toxic form for inhalation). A chronic occupational human study was used to
define the lowest-observed-adverse-effect level (LOAEL) of 0.026 mg/m3 for chronic
exposure to mercury vapor in air (4, 6). In that study the adverse effect observed was an
increase in the fme tremors that all people have normally. There is also some indication
from other studies that some memory loss and mild kidney effects may occur at this TO AFT.
The maximum concentration of mercury vapor measured in air over the flood plain
(0.0000124 mg/m3) is 2000 times less than the LOAEL of 0.026 mg/m3 (2, 4, 6). Thus, air
concentrations of mercury vapor over flood plain soil at its present level of contamination are
much lower than the LOAEL. The air concentrations of mercury vapor over soil with only
180 mg/kg mercury will be even lower.
DISCUSSION
Exposure Routes
We have considered a worst-case scenario involving children who are exposed to mercury in
East Fork Poplar Creek flood plain soil at a clean up level of 180 mg/kg of mercury. Our
assumptions provide a substantial margin of safety in assessing the health hazard to the
community.
The residential land use scenario provides the maximum opportunity for chronic exposure to
the mercury in the East Fork Poplar Creek flood plain soil. Children in the residential areas
have the greatest risk of exposure to mercury because they are likely to have the most
frequent and longest duration exposure to East Fork Poplar Creek soils since they play in the
dirt and engage in frequent hand to mouth activity and often mouth objects.
The frequency and duration of exposure to East Fork Poplar Creek flood plain soil is likely
to be much less for adults in general and particularly for people who do not live on the flood

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plain. Within the commercial, DOE, and recreational (e.g., sportsman club and golf course)
areas, access to the flood plain is either difficult or restricted. Within the agricultural areas,
people intermittently enter the flood plain. Consequently, people would more probably have
infrequent and short-duration exposures to mercury via ingestion of inorganic mercury in soil
or inhalation of mercury vapors in the air.
Ingestion of Mercury From Soil
We believe the proposed clean-up level of 180 mg/kg of mercury in East Fork Poplar Creek
flood plain soil will pose no health threat to children or adults.
Swallowing dirt is the most probable route of exposure to inorganic mercury compounds in
the East Fork Poplar Creek flood plain. The hazard from ingesting inorganic mercury is
primarily based on absorption into the bloodstream (internal dose). Different forms of
inorganic mercury compounds (mercuric chloride and mercuric sulfide are different "forms"
of mercury) have different absorption rates. Most of our information on absorption of
inorganic mercury after ingestion is from animal studies that used mercuric chloride.
We do not have any direct measures of the amount of mercury that children would absorb (7,
8). No laboratory studies are available on the percent absorption of inorganic mercury from
the gastrointestinal tract in humans (4). However, we know mercury can be absorbed by this
route because mercury has been detected in humans who have ingested inorganic mercury
compounds (mercuric nitrate, mercuric chloride, mercuric sulfide) (14, 15, 16).
Detailed animal studies indicate absorption of inorganic mercury across the gut is limited and
is influenced by the form of mercury and by an animal's age and diet, as well as its species.
For example, young rats may absorb much more mercury than old mice. Mercuric chloride,
the compound we used for our estimate, is used in many animal studies because it is very
soluble in water and is believed to have the highest absorption rate of inorganic mercury.
The absorption for mercuric chloride by this route ranges from as little as 1 % to as much as
38% in mice and rats (8, 9, 10). Studies suggest that some forms of mercury, for example
mercuric sulfide, have lower absorption rates or "bioavailability" through the gut than
mercuric chloride (11, 12, 13, 14). However, the relative bioavailability of mercuric sulfide
versus mercuric chloride has not been specifically studied in animals nor has it been
examined in humans (4). On the other hand we are reasonably certain that absorption is
much lower (approximately 0.1 %) for liquid metallic mercury (4). For this reason,
ingestion of metallic mercury is much less hazardous than ingestion of mercuric chloride. In
contrast, metallic mercury is dangerous if its vapor is inhaled, because metallic mercury
vapor is easily absorbed through the lungs (4).
Both animal and human data indicate that, after absorption into the blood, inorganic mercury
compounds go throughout the body but primarily accumulate in the kidneys (4). In animals,
the kidneys had the highest mercury levels following acute and intermediate oral exposure to

-------
mercuric chloride (11). For mercuric sulfide, higher doses were necessary before
accumulation was noted in the kidneys (11, 13, 14). The accumulation of mercury in the
brain and fetuses following ingestion of inorganic mercury compounds is substantially lower
than in the kidneys because the lipid solubility of inorganic mercury compounds is poor,
which prevents inorganic mercury compounds from crossing the blood-brain and placental
barriers (17). Taken together, these studies have shown that renal toxicity is the most
sensitive end point after ingestion of inorganic mercury.
Basis for Ingestion NOAEL and LOAEL: The no-observed-adverse-effect level (NOAEL)
is a dose of mercury that is based on the highest dose of mercury for which no adverse
health effect has ever been observed in animals. Specifically, the highest NOAEL of 0.23
mg/kg/day for intermediate oral exposure to inorganic mercury is based on rats given
mercuric chloride in an aqueous solution by gavage for five days a week for six months (4,
5). Our calculated worst case oral exposure dose of 0.001 mg/kg/day for children is
approximately 230 times less than this NOAEL.
The lowest-observed-adverse effect level (LOAEL) is also protective because it's based on
the lowest dose where any adverse effect has been observed in the kidneys of animals. The
intermediate LOAEL of 0.46 mg/kg/day (derived from six-month mercuric chloride study) is
based on a sensitive biomarker for the first appearance of renal toxicity, increased kidney
weight (4, 5). The chronic LOAEL of 1.9 mg/kg/day for inorganic mercury is based on
microscopic changes to certain components of the kidney (thickening of glomerular and
tubular membranes), changes that are likely to indicate more serious effects than kidney
weight change alone (4, 5). This chronic dose is derived from a two-year study in rats that
were exposed five days a week for two years to mercuric chloride in an aqueous solution by
gavage (4, 5). Only male rats experienced an adverse effect in their kidneys at this dose,
female rats did not. Furthermore, although adverse effects were seen in female mice in the
same study at a higher dose (3.7 mg/kg/day), the effects appeared less severe than in males.
Taken together, this and other evidence suggests that male rats may be particularly sensitive
to the effects of mercury exposure. The calculated chronic oral exposure dose of 0.001
mg/kg/day for children is approximately 460 times less than the intermediate LOAEL of
0.46 mg/kg/day and 1,900 times less than the chronic LOAEL of 1.9 mg/kg/day.
It is important to be cautious when generalizing from animal data. NOAELs and LOAELs
based on animal data are not human health guidelines per se. There is uncertainty in
extrapolating from them for the following reasons:
1) Rat data may not be directly applicable to humans (e.g., humans may be more
sensitive than rats).
2) Individuals may have different responses (some humans are likely to be more
sensitive than the average).

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3) Using a LOAEL does not give a clear threshold below which adverse effects do not
occur (i.e., we are not sure how much lower than the LOAEL we would have to go
before we would stop seeing the adverse effect entirely) .
However, we are confident that the proposed clean-up level of 180 mg/kg of mercury in the
flood plain soil will pose no health threat because the estimated oral exposure dose is so
much lower (2 to 3 orders of magnitude) than the relevant NOAEL and LOAELs.
We also don't expect adverse effects on other organ systems because the amount of mercury
necessary to cause adverse effects is higher for other organs than it is for the kidneys. For
example, no evidence of neurotoxicity was seen in mice administrated 0.74 to 2.2 mg/kg/day
of mercuric chloride in drinking water for 110 days and 7.4 to 14.8 mg/kg/day for an
additional 400 days (18). Also, no histopathological evidence of brain lesions was observed
in rats receiving doses of mercuric chloride as high as 3.7 mg/kg/day by gavage, five days a
week, for up to two years, or in mice receiving doses as high as 7.4 mg/kg/day by gavage,
five days a week, for up to two years (4, 5).
Finally our worst case ingestion scenario evaluates all the mercury in the East Fork Poplar
Creek flood plain soil as mercuric chloride, which assumes that the bioavailability
(absorption) of mercury in East Fork Poplar Creek soil is equivalent to that of mercuric
chloride in an aqueous solution. This assumption is conservative because the majority of
mercury forms in the soil are likely to be less bioavailable than mercuric chloride in aqueous
solution. This assumption provides an additional margin of safety in assuring that exposure
to East Fork Poplar Creek flood plain soil containing 180 mg/kg inorganic mercury will not
result in adverse kidney effects.
Inhalation of Mercury In Air
We believe air concentrations of mercury vapor over the East Fork Poplar Creek flood plain
soil will pose no health threat if soils are remediated to the proposed clean-up level of 180
mg/kg of mercury.
We predict very little exposure to mercury would take place through inhalation if soils are
cleaned up to 180 mg/kg. However, inhalation is the most toxic route of exposure to
metallic mercury. Therefore, we made conservative assumptions in the worst case scenario
for this exposure route.
The primary route of exposure to metallic mercury in soil is inhalation of mercury vapors in
the air. Once mercury vapors are inhaled, absorption into the bloodstream is substantial (4).
Approximately 74-80% of inhaled elemental mercury vapor is retained in human tissue (19,
20). Following inhalation, mercury is distributed throughout the body and accumulates
primarily in the kidney, as it does when ingested. However, the lipophilic nature of metallic

-------
mercury also allows it to readily cross the blood-brain and placental barriers and accumulate
in the brain and fetus (4, 17). Therefore, inhalation is a more toxic route of exposure.
Basis for Inhalation LOAEL: The central nervous system is the most sensitive target organ
in humans following inhalation of metallic mercury vapor. The lowest-observed-adverse
effect level (LOAEL) of 0.026 mg/m3 for chronic inhalation exposure to mercury vapors in
air is based on a study in which a significant increase in the average velocity of naturally
occurring tremors was observed in workers exposed to mercury vapors (0.026 mg/m3
average concentration) for an average of 15.3 years (range 1-41 years) (6). The range of
mercury concentration (0.0000031 to 0.0000124 mg/m3) measured in the air over flood plain
soil containing 3,000 mg/kg mercury is over 2,000 times less than the LOAEL of 0.026
mg/m3 (2, 4). Since air concentrations of mercury vapor over soil at 3,000 mg/kg mercury
will be much higher than over soil at 180 mg/kg mercury, we think chronic exposure to
mercury vapor from the East Fork Poplar Creek food plain soil with concentrations of 180
mg/kg mercury will not pose a health threat.
CONCLUSION
We conclude that the proposed soil clean-up level of 180 mg/kg mercury for the East Fork
Poplar Creek flood plain is safe. Our estimated ingestion dose is orders of magnitude lower
than the LOAEL and NOAEL for ingestion developed from U. S. Public Health Service
studies of animals fed mercuric chloride. Also, the measured concentration of mercury
vapors in the air are much lower than the LOAEL for chronic inhalation of mercury vapors.
Consequently we think the 180 mg/kg clean-up level for the East Fork Poplar Creek flood
plain soil will be protective for exposures through ingestion as well as through inhalation.
RECOMMENDATIONS
The following recommendations from ATSDR's previous health consultation should be
implemented or remain in effect:
1. As an interim action, post signs and restrict public access to East Fork Poplar Creek
flood plain areas with elevated mercury concentrations in the soil and sediment (1).
2. Continue the East Fork Poplar Creek fish advisory. Ensure that a sufficient number
of signs are posted, especially at the confluence of Poplar Creek, to wain the public
of the presence of contaminated fish in the creek (1).

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PREPARERS OF REPORT
Jack E. Hanley
Environmental Health Scientist
Energy Section B
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation
William H. Taylor, Ph.D.
Environmental Health Scientist
Energy Section B
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation
REVIEWERS OF REPORT
Heather Tosteson, Ph.D.
Writer
Program Evaluation, Records & Information Services Branch
Division of Health Assessment and Consultation
Richard A. Canady, Ph.D.
Toxicologist
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation

-------
REFERENCE
1.	Agency for Toxic Substances and Disease Registry. Health Consultation: Y-12
Weapons Plant Chemical Release Into East Fork Poplar Creek, Oak Ridge,
Tennessee. Atlanta, GA: Agency for Toxic Substances and Disease Registry, April
1993.
2.	U. S. Department of Energy. East Fork Poplar Creek-Sewer Line Beltway Remedial
Investigation Report, DOE/OR/02-1119&D2&V1. Oak Ridge, Tennessee: U. S.
Department of Energy, January 1994; Contract Number DE-AC05-910R21950.
3.	U. S. Department of Energy. Addendum to the East Fork Poplar Creek-Sewer Line
Beltway Remedial Investigation Report, DOE/OR/02-1119&D2/A1/R1. Oak Ridge,
Tennessee: U. S. Department of Energy, June 1994; Contract Number DE-AC05-
91OR21950.
4.	Agency for Toxic Substances and Disease Registry. Toxicological Profile for
Mercuiy. Atlanta: ATSDR, May 1994; DHHS publication no. ATSDR/TP-93/10.
5.	NTP. 1983. Toxicology and carcinogenesis studies of mercuric chloride (CAS no.
7487-94-7) in F344/N rats and B6C3F1 mice (gavage studies) as modified based on
peer review). National Toxicology Program, U.S. Department of Health and Human
Services, Public Health Service, National Institutes of Health, Research Triangle
Park, NC. NTP TR 408. NIH publication no. 91-3139.
6.	Fawer et al. 1983. Cited by: Agency for Toxic Substances and Disease Registry.
1994.	Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
7.	Endo et al. 1990. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
8.	Kostial et al. 1978. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
9.	Clarkson 1971. Cited by: Agency for Toxic Substances and Disease Registry. 1994.
Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994; DHHS
publication no. ATSDR/TP-93/10.
10.	Piotrowski et al. 1992. Cited by: Agency for Toxic Substances and Disease
Registry. 1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May
1994; DHHS publication no. ATSDR/TP-93/10.

-------
11.	Sin et al. 1983. Cited by: Agency for Toxic Substances and Disease Registry. 1994.
Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994; DHHS
publication no. ATSDR/TP-93/10.
12.	Sin et al. 1990. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
13.	Yeoh et al. 1986. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
14.	Yeoh et al. 1989. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
15.	Suzuki et al. 1992. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
16.	Rahola et al. 1973. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
17.	Clarkson. 1989. Cited by: Agency for Toxic Substances and Disease Registry. 1994.
Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994; DHHS
publication no. ATSDR/TP-93/10.
18.	Ganser et al. 1985. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
19.	Hursh et al. 1976. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.
20.	Teisinger et al. 1965. Cited by: Agency for Toxic Substances and Disease Registry.
1994. Toxicological profile for mercury (updated). Atlanta: ATSDR, May 1994;
DHHS publication no. ATSDR/TP-93/10.

-------
Oak Ridge-Pollution
DOE-ORGDP airborne uranium emissions 1946-1983.
n. d.
DOE-ORGDP
Airborne Uranium Qrassions
1946 - 1983
YEAR
Total Uranium
Radioactivity Released
(Ci/yrl
Total Mass of
Uranium Released (ka/vr)
1946
0.01
1
1947
<0.01
<1
1948
<0.01
5
1949
<0.01
45
1950
0.10
136
1951
0.02
146
1952
0.23
345
1953
1.60
1,307*
1954
0.26
68
1955
0.26
264
1956
0.81
225
1957
0.15
306
1958
1.80
2,711*
1959
1.10
531
1960
1.50
977
1961
3.10
773
1962
0.24
29
1963
3.10
1,005*
1964
0.01
7
1965
0.14
269
1966
<0.01
1**
1967
<0.01
2
1968
<0.01
<1
1969
<0.01
9
1970
<0.01
8
1971
0.02
21
1972
0.03
49
1973
0.13
144
1974
0.44
622
1975
0.27
371
1976
0.05
45
1977
0.03
17
1978
0.02
19
1979
0.04
25
1980
0.03
21
1981
0.01
5
1982
<0.01
2
1983
<0.01
2
TOTAL
15.601
10.5151
1nus total includes the actual stated value for any quantity which was reported as a less
than (<) value.
Note: The isotopic content of the uranium released varies strongly fran year to year
(Uranium-235 content varies from 0.2 percent to 90+ percent). the variability of
isotopic content and quantities released results in much year to year variation.
* A major portion of the quantities reported in 1953, 1958, and 1963 resulted frcra
accidental releases due to valve and trap failures in the K-402-1, K-1131, and K-l420
feed and processing facilities.
** Declining production levels was a factor which reduced emissions in the 1966-70 time
period"	OAK RIDGE ROOM
OAK RIDGE PUBLIC LIBRARY

-------
DOE-QRGDP
Liquid Effluent Uranium Releases
1946 - 1983
Total Uranium
Radioactivity Released	Total Mass of
year		(Ci/yii		Uranium Released (kg/yr)
1946	<0.01	<1
1947	—	—
1948	0.03	4
1949	<0.01	3
1950	—	—
1951	0.05	80
1952	<0.01	4
1953	0.10	26
1954	0.23	84
1955	0.05	16
1956	0.24	90
1957	0.18	40
1958	<0.01	<1
1959	<0.01	5
1960	<0.01	<1
1961	0.02	2
1962	0.01	2
1963	5.10**	1,576*
1964	1.10	1,826*
1965	0.01	33
1966	<0.01	21
1967	<0.01	12
1968	0.26	330
1969	0.04	3,180*
1970	0.86	88
1971	0.44	76
1972	0.40	1,601
1973	0.44	570
1974	0.4	508
1975	1.70	564
1976	0.54	306
1977	0.42	2,201*
1978	0.63	688
1979	0.47	537
1980	0.09	803
1981	0.18	601
1982	0.09	114
1983	0.18	233
TOTAL	14.34*	16,2271
— Indicates data not avail^1,1 e
^2his total includes the actual stated value for any quantity which was reported as a less
than (<) value.
Note: Itie isotopic content of the uranium released varies from year to year (Uranium-235
content varies from 0.2 percent to 90+ percent). Hie variability of isotopic content
and quantities released results in much year to year variations.
* A major portion of the quantities reported in 1963, 1964, 1969, 1972, ana 1977
resulted fran discharges to a pond from the decontamination facility.

-------
DOE-ORGDP
Uranium Contained in Solid Waste Buried on Site
YEAR
Total Uranium
Radioactivity Buried
(Ci/vr)
Total Mass of.
Uranium Buried (10
1958
1.20
1.79
1963
5.50
1.70
1964
1.10
1.99
196b
<0.01
<0.01
1966
0.99
1.93
1968
0.37
0.60
1969
1.80
4.78
1970
0.87
1.21
1971
0.08
0.13
1972
10.70
27.50*
1973
1.80
2.46
1974
0.55
0.71
1975
0.59
0.76
ms
0.95
1.34
MF
2.50
3.18
W8
0.85
1.09
1979
1.20
1.56
1980
1.20
1.86
1981
0.83
1.06
1982
0.43
0.55
1983
0.18
0.29
TOTAL
33.70
56,500 kgs
>te: The ratio between curies and mass differs from year to year due
to varying isotopic enrichments.

-------
Surface Water Concentration
10 Ci/mL
Year
*No. 1
*No. 2
*No. 3
*No. 4
*No. 5
*No. 6
Concentratio
Guide
1959
6.2

0.6



2,000
1960
3.1

0.7
0.14
0.27

2,000
1961



0.16
0.25

2,000
1962



0.06
0.2

2,000
1963






2,000
1964



0.1
0.1

2,000
1965



<0.1
<0.1

2,000
1966




<0.1

2,000
1967




<0.1

2,000
1968




<0.2

2,000
1969




<0.1

2,000
1970




<0.1

2,000
1971

2.5
7.1

0.3

2,000
1972

1.0
0.4

0.2

2,000
1973

0.6
0.1
<0.2
0.2

3,000
1974

3.2
2.1
0.5
0.3

3,000
1975

1.6
1.0
0.3
0.4

3,000
1976

1.2
1.4
0.5
<0.6
<0.5
3,000
1977

1.0
0.6
0.3
0.2
0.3
3,000
1978

<0.3
<0.4
<0.1
<0.3
<0.3
3,000
1979

<0.4
0.5
<0.2
<0.3
<0.2
3,000
1980

<0.2
<0.4
<0.09
<0.2
<0.1

1981

0.5
0.6
<0.01
<0.1
<0.2
~ ~
1982

<0.2
<0.3
<0.1
<0.1
<0.1
**
1983

<0.4
<0.4
<0.2
<0.2
<0.2
**
*1. Mouth of East Fork Poplar Creek
*2. Above K-25 Poplar Creek
*3. Mouth of Poplar Creek
*4. Above K-25 Clinch River
*5. Below K-25 Clinch River
*6. Brashear Island Clinch River
** - Beginning in 1980, a dose standard as opposed to the concentration

-------

-------
ORGDP Annual Air Concentration
(I960 - 1965)
10"1J yCi/mL
Yea?;
1960*
1960*
Distance Frcm
QRGDP
2 miles
5 miles
Average***
Concentration
1.1
3.1
Concentration
Guide
20
20
1961
1961**
2 miles
5 miles
0.4
1.0
20
20
196 2	5 miles	1.6	20
1963	5 miles	4.0	20
1964	5 miles	2.5	20
1965	5 miles	0.8	20
* Not included in this data are thirty-two samples taken in early
November which coincided-.with an onsite pilot plant operation. Hiese
values shewed 188 x 10 yCi/mL at two miles and 110 x 10 pCi/mL
at five miles.
** After 1961 the two mile stations were not maintained.
*** Hie values in Table 4 are higher than the values in Table 5 because the
data in Table 4 were collected without waiting for the background
daughter products to decay. The air monitors used during this period
automatically counted the air samples only 4.5 hours after collection.

-------
s
ni'x-10
On Mlijliway
12 Mllcs from OnGDP
SAMI'l.IIIG POINTS OF OUISIDE EtlVIHUIS — OftCDP
A1 r
A S.nnpl lnq location - b Miles (icrni Plant

-------
Annual Air Concentration (1966^3.983)
(Average Gross Alpha Activity - 10 y Ci/mL)
Location HP - 33
Year	Gallaher Gate
1966	5.0
1967	3.0
1968	1.5
1969	1.5
1970	1.0
1971	1.0
1972	2.0
L973	1.6
1974	1.5
*975	1.4
1976	1.7
1977	1.6
1978	1.1
1979	1.2
1980	1.1
1981	0.8
1982	1.1
1983	1.3
I
~Percentage of
Concentration
Guide (%)	
.12
.07
.04
.04
.02
.02
.05
.04
.04
.03
.04
.04
.03
.03
Location HP-35
Blair Gate
7.0
5.0
2.0
2.0
1.0
1.0
3.0
2.3
1.6
1.6
3.1
1.3
2.2
1.5
1.5
0.9
1.0
1.0
~Percentage ot
Concentration
Guide
.17
.12
.05
.05
.02
.02
.07
.06
.04
.04
.08
.03
.05
.04
**
-12
* The applicable concentration guide until 1980 was 4.0 x 10 yCi/inL.
** Beginning in 1980, a dose standard as opposed to the concentration

-------
DWG. NO. K/G-8 5-4 26 I
-------
Urararm In Soil
(y^g)

J575
1976
1977
_I578
1979
1950
Ml
1982*
1983
\s-l
2J.
15
4J.
3.0
2.4
2 J
23
15
43
\5-2
4.8
15
1.0
1.7
1.6
3.0
3.4


\S-3
1J.
1J.
2.0
3 J.
2.6
23
33


\5-4
0.4
0.8
1.1
1.8
3d
1.9
33


V3-5
1J.
0.6
2.4
2.7
23
25
23
23
4.7
MS-6
0.9
1JL
2J.
43
4.6
1.8
3.9


VS-7
05
0.8
23
23
2.0
5.4
2J5


\S-8
1J
1.7
43
5.8
4J.
55
4J.
4.9
4.6
\E-9
0.8
0.4
1J6
2.7
2.6
45
2.4
1.8
2.4
\S-10
0.6
03
3.4
3.9
23
23
1.8
2J0
23
\5-H
1.4
0.9
23
45
4.9
25
53
4 Jo
6.0
\EHL2
1.0
0.6
1.8
2 J.
3.4
2.0
2.9


VS-13
23
2.8
4.2
4.9
3.7
23
2.8
25
3.7
MS-14
13
1.9
22
2.4
33
15
23


VS-15
15
1.0
3.7
35
4.0
33
5.4
33
3.8
\S-IS
1.0
2.4
1.9
2 J)
4J.
23
25
1.6
2.8
\5-17
2.9
1.0
5.8
65
33
33
1.6
23
1.6
ftllBl
/verags
15
1.2
2.7
33
33
2.8
3 J.
2.7
3.6
-------
Urarriim in Pine EfeeflLss
(yg/g)

1974
2975
1376
Ml
.1578
1979
1980
1951
1962
1983
VS-1
-------
Uraniiin in tess
(yg/g)

1974
1975
1576
_1S77
1978
1979
1950
1981,
mz*
1983
\5-l
OJ
03
03
0.20
0.2
OJ
0.6
03
0J2
031
VS-2
0.6
OJ
OJ
0.08
0.05
OJ
1.6
0.2


VS-3
OJ
OJ
OJ
0.04
0.04
OJ
1.2
0.06


V5-4
0.2
03
0.7
038
0.2
OJ
0.7
OJ


VS-5
<0J
OJ
0.2
0.07
03
OJ
0.7
0.4
03
0.20
\S-6
<0J
03
0.2
0.07
0.6
0.08
0.6
0.2


VS-7
<0J
0.2
OJ
0.06
0.5
OJ
03
03


\S-8
<0J
0.4
03
0.29
1 JO
0.2
0.6
0.2
0.2
0.08
\iS-9
«0J
03
OJ
1.22
0.4
0.2
0.7
0.2
OJ
0.06
\S-10
«0J.
<0J
OJ
0J6
0.4
OJ
03
0.2
0.2
0.05
JS-U


0.4
0.53
1.2
0.7
1.7
03
0.4
0.08
|*2


0.2
0J2
0.4
0.2
0.4
0.2


\S-13


OJ
0.5L
0.8
OJ
1J
0.6
0.6
0.63
\E-14


03
0.27
03
0.04
03
0.02
<0J

V5-15


OJ
0.07
03
0.04
0.6
0.2
0.2
0.08
^5-16


OJ
0.04
03
OJ
1.2
0.2
OJ
0J2
VS-11


OJ
0J2
1J
0.4
0.8
0.06
OJ
0J1
ftixal
Ata. cjje
<0.2
<0.2
0.2
0.2
03
0.2
0.8
0.2
0.2
03
-------
Groundwater Uranium Concentration*
10 yCi/mL

1979
1980
1981
1982
1983
#1
<0.067
<0.067
<0.067
0.134
0.067
#2
<0.067
<0.067
0.134
0.067
0.201
#3
<0.067
<0.067
<0.067
<0.067
0.134-
#4A



0.067
0.738
#5
<0.067
<0.067
<0.067
<0.067
0.201
#6
0.134
0.201
0.134
0.268
0.335
#7A



0.134
0.268
#8A



<0.067
0.536
#9A



0.201
0.536
#10A



0.201
0.402
#11



0.134
0.268
#11A



0.671
0.201
#12



<0.067
<0.067
#12A



0.469
<0.067
#13



0.067
<0.067
#13A



0.067
0.067
#14



0.201
<0.067
#14A



0.067
<0.067
#15A



<0.067
0.201
#16A



0.402
0.671
#17A



0.201
<0.067
-------
ORGDP
GROUNDWATER MONITORING WELLS
14A
4*.:
13A ©O 6 11A -	
12A © O© ^
O SHALLOW* WELLS
© DEEP WELLS
K-1407B
K-1420
y
K-1401
016A
-------
Uranium in Stream Sediments
( yg/g)

1976
1977
1978*
1979
1980
1981
1282*
1983
CS-1
0.4
2.1
16
2
1
1
1
4
PS-2
3.4
10.4
15
17
8
7


PS-3
4.1
10.8






PS-4
8.6
15.9






PS-5
11.1
4.9
9
5
6
6


PS-6
11.6
38.5
14
14
18
11
6
9
PS-7
59.5
4.5






PS-8
6.1
5.3






PS-9
17.8
22.6
4
6
4
3


PS-10
18.2
4.9
21
4
17
18
10
9
PS-11
2.4
9.5






PS-12
4.8
4.5
17
17
4
9


PS-13
23.4
5.9






PS-14
6.3
20.9






PS-15
12.6
8.1
95
14
31
31


PS-16
62.1
42.0






PS-17
4.5
90.8
12
181
13
13
59
65
PS-18

12.1
6
6
4
6
13
9
PS-19

15.3
9
17
9
12
10
13
PS-21


13
7
7
1
8
13
PS-22


10
12
8
7


CS-20

1.4
8
1
1
11
1
1
* In 1978 and again in 1982, the number of stream-sediment sampling
-------
-------
Y-12 PLANT
AIRBORNE URANIUM EMISSIONS
Year
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
Total Measured
Estimated
TOTAL MEASURED AND ESTIMATED
Uranium
Measured (Curies)*
0.20
0.20
0.25
0.35
0.45
0.45
0.50
0.70
0.60
0.40
0.45
0.45
0.35
0.35
0.40
0.05
0.01
0.01
0.09
0.11
0.11
0.06
0.01
0.06
0.16
0.12
0.11
0.12
7.2
U.
8.3
* Uranium measured is given in curies for each year and is based
on monitoring results (principally for enriched uranium) and/or
accountability data. Estimated quantities are provided for nonmon-
itored sources. The total of 8.3 curies is equivalent to approxi-
-------
Y-12 PLANT
LIQUID URANIUM EFFLUENTS
Year
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
TOTAL
Uranium
Measured (Curies)*
0.71
0.62
2.26
5.65
5.85
5.15
4.55
2.00
0.86
0.82
4.42
5.91
5.34
10.20
11.75
2.80
5.88
2.37
2.03
0.74
1.04
1.09
0.91
0.50
0.27
0.24
0.10
0.45
0.56
0.14
85.21
* Uranium measured is given in curies for each year (Ci/yr) and is
based on monitoring results and/or accountability data. The total
of 85.21 curies is equivalent to approximately 280,000 pounds
-------
Y-12 Plant
Uranium Contained in Solid Waste Buried on Site
Uranium
Year	Buried (Curies)*
1954	<0.1
1955	<0.1
1956	12
1957	52
1958	74
1959	120
1960	120
1961	750
1962	150
1963	100
1964	320
1965	190
1966	650
1967	460
1968	140
1969	260
1970	330
1971	390
1972	530
1973	340
1974	460
1975	230
1976	180
1977	150
1978	210
1979	230
1980	790
1981	490
1982	350
1983	390
TOTAL	8,468
* Total uranium contained in solid waste buried on site is given
in curies for each year and is based on accountability data. The
total of 8,468 curies is equivalent to approximately 52,000,000
-------
Y-12 Plant Average Uranium Concentration Data from
Area Air Monitoring Stations
-15
(Average Gross Alpha, xlO yCi/mL)
Station*

HP-
HP-
HP-
HP-
HP-
HP-
HP-
Year
21
22
22..
id**
41**
21
55.
1966
6
7
6


4
3
1967
3
5
5


3
3
1968
2
2
2


2
1
1969
2
2
2


2
1
1970
1
3
1


1
1
1971
<1
<2
<1


<1
<1
1972
2
3
2


2
2
1973
1.7
2.6
1.8


1.4
1.9
1974
1.3
1.6
1.3


1.0
1.3
1975
1.0
1.4
1.2


1.0
1.1
1976
1.1
1.7
1.4


0.9
<0.9
1977
0.9
1.2
1.1


<1.0
0.9
1978
1.1
1.4
1.1


0.9
<0.9
1979
1.1
1.4
1.2


0.9
0.7
1980
0.9
1.1
0.9


0.9
1.5
1981
0.79
1.1
0.84


0.92
1.3
1982
0.92
1.1
0.86


0.78
1.1
1983
0.93
1.4
0.98
2.2
2.0
0.66
1.2
* See Figures 1 and 2 for location of monitoring stations. Station HP-31,
32, 39, 40, and 41 are related to the Y-12 Plant. Stations HP-37 and 55 are
background stations.
-------
Y-12 Plant Average Uranium Concentration Data from
Area Air Monitoring Stations as Percent of Applicable
DOE Concentration Guides
Station*








I DOE Cone.









Guide

HP-
HP-
HP-
HP-
HP-
HP-
HP-


Year
21
22
22.
40.**
41**
21
55.
I xlO yCi/mL*
1966
0.30
0.35
0.30


0.20
0.15
| —

1967
0.10
0.20
0.15


0.15
0.15


1968
0.10
0.10
0.10


0.10
0.05


1969
0.10
0.10
0.10


0.10
0.05

> 2000
1970
0.05
0.15
0.05


0.05
0.05


1971
<0.05
<0.1
<0.05


<0.05
<0.05


1972
0.1
0.15
0.1


0.1
0.1
| —

1973
0.04
0.07
0.05


0.04
0.05


1974
0.03
0.04
0.03


0.03
0.03


1975
0.03
0.04
0.03


0.03
0.03


1976
0.03
0.04
0.04


0.02
<0.02


1977
0.02
0.03
0.03


<0.03
0.02

? 4000
1978
0.03
0.04
0.03


0.02
<0.02


1979
0.03
0.03
0.03


0.02
0.02


1980
0.02
0.03
0.02


0.02
0.04


1981
0.02
0.03
0.02


0.02
0.03


1982
0.02
0.03
0.02


0.02
0.03


1983
0.02
0.03
0.02
0.05
0.05
0.02
0.03


* See Figures 1 and 2 for location of monitoring stations. Stations HP-31,
32, 39, 40, and 41 are related to the Y-12 Plant. Stations HP-37 and HP-55
are background stations.
** Stations HP-40 and HP-41 were started in 1983.
*** DOE concentration guides are listed in Appendix B, Table 2. The value
of 4000 x 10" yCi/mL is the lcwest limit specified for uranium. Prior
to 1973 a different definition of the curie was used, resulting in a different
-------
OIIMI |)W(; n M44II4
-------
(MINI l)UV(> (jli I / I'llli
[hp-sy pale hollow pam)*
Jb milei	**
	
S3 DOUGLAS DAM]
42 mile*
*v
/
-------

Y-12
PLANT URANIUM IN SOIL DATA
(pCi/g)
Station*



HP-
HP-
HP-
HP- HP-
HP-
HP-

21
21
21
40.** 41**
21
55***
1971
0.11
0.07
0.63

0.14

1972
0.25
0.47
0.48

0.11

1973
0.64
0.77
0.28

0.16

1974
0.81
1.17
1.13

0.99

1975
1.80
1.70
0.59

0.26

1976
1.42
1.09
0.55

N/A
0.55
1977
0.79
3.41
1.99

0.51
0.88
1978
0.84
1.63
0.96

0.49
0.79
1979
0.64
2.31
2.03

0.69
0.78
1980
1.31
1.92
1.15

1.01
0.72
1981
1.05
2.23
1.86

0.52
1.14
1982
0.27
0.35
0.38

0.04
0.04
1983
0.98
2.65
1.38
8.76 0.69
0.72
0.67
* See Figures 1 and 2 for location of monitoring stations. Stations HP-31,
32, 39, 40, and 41 are related to the Y-12 Plant. Stations HP-37 and HP-55
are background stations.
** Stations HP-40 and HP-41 were started in 1983.
*** Station HP-55 was established in 1955.
-------
Y-12 Plant Average Uranium Concentration Data for
Surface Water Monitoring Stations
(xlO ® yCi/mL)
Station

E-l*
Brl**
C-3***
1971
24
23

1972
27
21

1973
8.5
3.5
<0.2
1974
6.3
5.6
0.5
1975
6.3
5.0
0.3
1976
4.0
6.8
0.5
1977
2.3
2.9
0.3
1978
1.1
1.8
<0.1
1979
1.0
2.6
<0.2
1980
5.2
1.8
<0.09
1981
4.1
3.6
<0.1
1982
2.1
4.1
<0.13
1983
2.9
3.0
<0.17
* East Fork Poplar Creek Station
** Bear Creek Station
-------
Y-12 Plant Average Uranium Concentration Data for
Surface Water Monitoring Stations as Percent of
Applicable DOE Concentration Guides
Station
Year
1971
1972
E=i3
1.2
1.4
B-l4
1.2
1.1
C-35
I DOE Cone.
I Guide
I xlO"8 (uCi/mL)
1^ 2000
1973
0.3
0.1
<0.1
I 1

1974
0.2
0.2
<0.1


1975
0.2
0.2
<0.1


1976
0.1
0.2
<0.1

L 3000
1977
<0.1
<0.1
<0.1


1978
<0.1
<0.1
<0.1


1979
<0.1
<0.1
<0.1


1980
0.2
0.1
<0.1


1981*
1982^
1983
6.8
3.5
4.8
6.0
6.8
5.0
<0.2
<0.2
<0.3
1
I 60
* For years 1981-1983 values for Stations E-l and B-l are a higher
percentage of the DOE concentration due to a reduction in the guide.
2
DOE concentration guide is listed in Appendix B, Table 4. The value of
60 x 10 pCi/mL is the lowest limit specified for uranium. Prior to 1973
a different definition of the curie was used, resulting in a different
concentration guide.
3
East Fork Poplar Creek Station
4
Bear Creek Station
-------
fifiril [i*i. " Ml.
-------

EXPLANATION
VOCl IN OROUND WATER
1984
Q 10 TO 1.000 jiall
> i.ooo fi^n
A > so.ooo yan
= PAVED ROAD
— DIRT/GRAVEL
" ROAD
BURIAL GROUNDS
OIL LANDFARM
S-3 PONDS
03
I
U1
1000 FT
-------
EXPLANATION
NITRATE (N) IN GROUND
WATER 19 84
fr*] EXCEEtHNQ 1,000 m^n N
[/] 10 TO 1.000 ng/l N
	 PAVED ROAD
-- DIRT/GRAVEL
ROAD
BURIAL QR0UND8
OIL LANDFARM
8-3 PONDS
00
I
o\
I000FT
-------
 0.002 ¦g(|)
BURIAL GROUNDS
?
OIL LANDFARM
8-3 PONDS
1000 FT
o
>i
P
00
XT
fe>
s
E:
o
3
o
-------
Oak Ridge Soil Uranium *
Sewer-Line Beltway
East Fork Poplar Creek
Floodplain (general)
East Fork Poplar Creek
Floodplain (isolated areas)**
NRD Guideline for
Unrestricted Areas
2.8 - 38 pci/g
3-44 pci/g
13.2 - 146 pci/g
30 - 35 pci/g
* Data Collected by ORAU
-------
Parameter
SCRAP YARD SOIL
SCREENING SAMPLE RESULTS
# of
Samples
Range (ppm)
Uranium*
PCB**
Mercury***
19
19
238
16 - 600
4.3 - 380
1.0 - 6700
* NRC Guideline 44-51 ppm (natural U)
** EPA Standard 50 ppm.
-------