BIO AVAILABILITY OF DIOXINS AND DIOXIN-
LIKE COMPOUNDS IN SOIL
Peer Review Report
Prepared by:
U.S. Environmental Protection Agency, Office of Solid Waste and Emergency
Response, Office of Superfund Remediation and Technology Innovation
With contributions from:
CMS
Environmental Management Support, Inc.
May 4, 2011
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TABLE OF CONTENTS
LIST OF APPENDICES iii
EXECUTIVE SUMMARY iv
1.0 INTRODUCTION 1
1.1 Background 1
2.0 PEER RE VIEW PROCESS 2
2.1 Peer Review Charge 2
2.2 Summary of Finding 3
3.0 RESULTS 4
4.0 REFERENCES 4
Page ii
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LIST OF APPENDICES
Appendix A-Peer Review Comments A-l
Appendix B - Peer Review Materials B-2
Page iii
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EXECUTIVE SUMMARY
The Peer Review Panel (herein referred to as Panel) reviewed the report titled Bioavailability of
Dioxins in Soil and Soil-Like Materials (herein referred to as Report) to address 16 charge
questions regarding the information contained in the document.
The Report presents a summary of the published literature and analysis of the available data
regarding relative bioavailability (RBA) of polychlorinated dibenzo-p-dioxins (PCDD) and
polychlorinated dibenzofuran congeners (PCDF) in soil1.
The external peer review resulted in an editorial revision of the Report. Peer Review findings
are summarized below in Section 2.2 Summary of Findings and Section 3.0 Results. The revised
final Report may be found at
http://www.epa.gov/superfund/health/contaminants/dioxin/dioxinsoil.html
Soil defined in this report include but not limited to studies utilizing media such as sediments and other materials
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1.0 INTRODUCTION
1.1 Background
The Risk Assessment Guidance for Superfund (RAGS) Part A (USEPA 1989) discusses making
adjustments to Superfund site-specific risk assessments when the medium of exposure in an
exposure assessment differs from the medium of exposure assumed by the toxicity value (cancer
slope factor, reference dose value, etc.) based upon site-specific bioavailability data. An
important consideration in assessing risks from exposures to dioxin in soil is whether an
adjustment is needed in the application of the cancer slope factor (CSF) and/or chronic reference
dose (RfD) for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD). This adjustment would account
for differences in the bioavailability of TCDD (and lexicologically related polychlorinated
dibenzo-p-dioxins [PCDD] and polychlorinated dibenzofuran congeners [PCDF]) in soil and in
the test medium used in the critical study(ies) on which the CSF and/or RfD were based (e.g.,
dietary exposure vs. exposure to soil). An adjustment may be considered appropriate if evidence
were sufficient to indicate that the relative bioavailability (RBA) of the PCDD/F mixture in soil
was less than 100%. This report presents a review of the published literature and analysis of the
available data regarding RBA of PCDD/F in soil.
The principal objectives of this literature review and data analysis are as follows:
1. Identify and summarize published literature potentially relevant to estimating RBA of
PCDD/Fs in soil. Select studies that meet predetermined quality considerations.
2. Evaluate data contained in this literature to evaluate whether they are adequate and
sufficient to conclude that RBA for PCDD/Fs RBA in soil is less than 100%.
3. Consider use of these data, if adequate and sufficient, to recommend a quantitative
central tendency and upper bound estimate of RBA when developing site-specific
cleanup levels for dioxin in soil.
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2.0 PEER REVIEW PROCESS
2.1 Peer Review Charges
The Report qualifies as a technical document and is eligible for an independent peer review of
the content. EPA retained Environmental Management Support, Inc. (EMS) to conduct an
independent peer review of the Report. EMS conducted the review of the technical document in
accordance with the EPA's Science Policy Council Peer Review Handbook (third edition, June
2006). Management of the review consisted of the following general activities:
• Identified areas of expertise necessary for a scientifically rigorous review.
• Identified a list of candidate expert peer reviewers.
• Evaluated the expertise of each of the candidate expert peer reviewers.
• Created a short list of candidate expert peer reviewers.
• Determined the interest and availability of the short list of candidate expert peer
reviewers.
• Determined for each of the remaining list of candidate peer reviewers any potential
conflict of interest or lack of impartiality, or the appearance of any potential conflict of
interest or lack of impartiality; excluding candidates with either.
• Finalized a team of three expert peer reviewers.
• Developed charge questions in conjunction with EPA for the conduct of the peer review.
• Initiated the review.
• Coordinated the peer reviewers to finalize their written reviews.
This peer review was conducted as a letter review. Each of the reviewers was provided with a
copy of the Report and charge questions. A copy of all the materials provided to the expert peer
reviewers is included in this document.
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In seeking candidates to serve as expert peer reviewers, as well as selecting the final team of
reviewers, an effort was made to include individuals with expertise in one or more of the areas
identified by EPA:
• Exposure and Risk Assessment
• Human Health Toxicity
• Pharmacokinetics
• Bioavailability
• Dioxin and Dioxin-Like Compounds in soil.
The final team of expert reviewers consisted of the following individuals:
• Dr. Michael DeVito, National Toxicology Program, National Institute of Environmental
Health Science;
• Dr. Michael Honeycutt, Texas Commission on Environmental Quality; and
• Dr. Stephen Roberts, University of Florida.
Each of the reviewers was allowed four to six weeks to complete the review. Upon receipt of the
letter reviews, each one was reviewed and formatted for EPA's review. A brief summary of the
findings from the reviews are included below. Each of the final reviews is included as an
attachment to this document.
2.2 Summary of Findings
• Each of the reviewers agreed that the RBA of dioxin in soils is less than 100%.
Two of the three reviewers agreed that there were insufficient data to support a
nationally-applicable value for RBA for use in risk assessments. The reviewer who did
not agree recommended assigning a national RBA value less than 100% as a compromise
due to the lack of data from a statistically balanced study on dioxins RBA in soil, but did
not provide a scientifically defensible basis for doing so.
• Two of the three reviewers agreed that the current literature does not support a preferred
animal model for use as an animal bioassay. The reviewer who disagreed preferred the
swine model for an animal bioassay.
• None of the reviewers cited additional critical studies that could be included in the
Report's analysis.
• The reviewers identified critical points of clarification that would be required to calculate
a nationally applicable RBA. The reviewers focused on multiple doses in soil, animal
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model disparities and soil characteristics that would influence the bioavailability of
dioxin when ingested.
• The reviewers agreed that while the animal models presented in the Report (rat and
swine) are appropriate and commonly used in bioavailability studies, the limited data
available for species comparison and conflicting results on the degree of bioavailability
suggest they do not produce equivalent results.
• There was consensus that congener chlorine content will influence the KB A of the
congeners.
• The reviewers agreed that additional studies are required to establish a standard animal
protocol to be used to determine a site-specific RBA for dioxin.
3.0 RESULTS
The external peer review resulted in an editorial revision of the initial Report. The peer
reviewers' comments did not recommend revising the Report's scientific content or change its
conclusions.
The revised final Report may be found at
http ://www. epa.gov/superfund/health/contaminants/dioxin/dioxinsoil .html.
The following sections include the peer review questions and comments (Appendix A) as well as
the original peer review materials (Appendix B).
4.0 REFERENCES
USEPA 2006, Science Policy Council Peer Review Handbook, Third Edition, June 2006,
http ://www. epa.gov/peerreview
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Appendix A - Peer Review Comments
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CHARGE QUESTIONS to REVIEWERS
for Peer Review of Draft Report, "Bioavailability ofDioxins In Soil
and Soil-Like Materials: Literature Review and Data Analysis " July 2010.
Michael DeVito, PhD
Section 1 General Charge Questions
1.1. Is the draft document Bioavailability ofDioxins in Soil and Soil-like Materials: Literature
Review and Data Analysis clearly written and logical?
The draft document was clearly written and presents a logical argument
1.2. Are the objectives of the literature review clearly stated?
Yes
1.3 Has EPA objectively and clearly presented the rationale for its conclusions relevant to
estimating the relative bioavailability (RBA) of TCDD or other PCDD/Fs in soil?
Yes
1.4 Do you agree with EPA's major conclusions regarding RBA of TCDD or other PCDD/Fs in
soil? EPA's major conclusions are as follows:
a) RBA in soil is less than 100%
I agree
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b) data currently available are not sufficient to estimate a nationally-applicable
value for RBA for use in risk assessment (i.e., as an alternative to 100% or site-
specific values)
I disagree. Since EPA concludes that RBA in soil is less than 100%, then using
100% is inappropriate. Based on the studies presented, the highest RBA of the
soils tested is approximately 50%. One alternative to using the RBA of 100% is to
assign an RBA of 75%. This is higher than all other soils tested, but may be a
reasonable compromise due to the lack of data from a statistically balanced
study on dioxins RBA in soil.
c) data currently available are not sufficient to determine the preferred animal
species for use as an animal bioassay for predicting soil RBA in humans
I agree
d) site-specific data are recommended to develop site-specific cleanup levels.
I agree
If you disagree with any of the above conclusions, please comment on deficiencies in
the conclusions or alternative conclusions that could be derived from the data.
1.5. Are you aware of other critical studies that would make a substantial impact on EPA's
conclusions regarding RBA of TCDD and/or other PCDD/Fs?
Other than site specific data presented in this report, I am not aware of any other studies.
Section 2 Transparency and Clarity in the Selection of Key Data Sets for Relative
Bioavailability Analysis
2.1. Is EPA's approach for selecting key studies and data sets from the key studies
scientifically justified and clearly described?
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Yes
2.2. Are the chosen data sets adequate for estimating RBA values for each tested soil in each
of the studies?
I would be a little concerned with studies using only one dose level because of the dose
dependent disposition of dioxins. While they can identify soils that are not 100%
bioavailable, using a single dose level may tend to underestimate the bioavailability of a
particular soil
2.3. Are the data relied upon for the estimation of RBA for each tested soil in each of the
studies, applied in a scientifically sound manner?
Yes
2.4. Please comment on deficiencies, substantial inadequacies of the selected studies and
data sets, and provide suggestions for existing or future studies that could inform the
assessment of soil RBA.
One of the major assumptions used in these bioavailability studies is that of first order
pharmacokinetics of TCDD and related congeners. Recent studies demonstrate that
TCDD induces its own elimination and that there are dose dependent distribution of this
chemical due to the induction of CYP1A2 and binding of dioxins to CYP1A2. Since this
contrasts the assumption of first order elimination, single dose studies or other studies
that do not take into account the dose dependency of the distribution and elimination
would produce inaccurate estimates of the bioavailability of these chemicals. Most of
the studies included in this report used only a single dose level of TCDD or related.
While these studies clearly demonstrate that the dioxins in soil are not 100%
bioavailable, they may underestimate the true bioavailability of dioxins from the soil.
Section 3 Use of Animal Bioassays to Estimate Relative Bioavailability
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3.1. Are the animal models presented in this report appropriate for estimating RBA of TCDD
and other PCDD/Fs in soil? Please also comment on the criteria EPA has used to evaluate
the animal models:
The animals examined in this report are appropriate models to compare the relative
bioavailability. The key point is the relative bioavailability and not actual bioavailability.
Any of the experimental models used can provide useful information on the relative
bioavailability. The use of some of the models to predict actual bioavailability would
present some challenges.
a) similarities of physiology and anatomy of the animal model and human
gastrointestinal tract
This is the an important parameter to consider when choosing an animal model
b) similarity of distribution of absorbed PCDD/Fs in adipose tissue relative to liver
This parameter has little impact on the cross species extrapolation of RBA, but would
have an important influence on the estimate of the RBA in a particular species. As
long as this is accounted for in the experimental design, then it should have little
influence in the cross species extrapolation of the RBA.
c) Ah receptor binding, CYP450 induction, and clearance of PCDD/Fs
This parameter has little impact on the cross species extrapolation of RBA. As
long as the dose dependent induction and clearance of dioxins is considered in
the experimental design, then these parameters should have little impact on
extrapolating the RBA to humans.
3.2. What is your opinion of the observation that the effect of chlorine number on RBA is
different in swine and rats?
a) in swine, RBA appears to increase with increasing chlorination
b) in rats, RBA appears to decrease with increasing chlorination
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I am a little hesitant to make these statements due to the limited data available.
For example, in the swine data presented in Figure lit looks as if tow data points
really drive this relationship. The first point is the bioavailability value from
W107 SW for TCDD. This is based on two data points one of which overlaps with
the BU08 SW data and on that is approximately 10 fold lower. The second point
is from BU08 SW for the heptachlorinated dioxins and this is approximately
double that of the WI07 SW data. If you took these two points out, there
probably would not be a significant relationship between chlorine content and
bioavailability.
For rats, EPA uses the Budinsky and Finley studies. I do not agree with lumping
these data together. These data sets are too variable to make sense. For
example, they are using different soil types, congener patterns and
concentrations of dioxins. These differences in the studies most likely are the
cause of the large variability in the RBA estimates for the penta and hexa dioxins.
I think the data is not of sufficient quality to make broad statements on the
bioavailability differences between species and congeners.
Please comment on how this observation conforms or conflicts with information
regarding bioavailability provided by the National Academy of Science (NAS, 2006),
World Health Organization (Van den Berg et al. 2006), and U.S. EPA (2003). Note that
the swine studies (Budinsky et al., 2008; Wittseipe et al., 2007) included in EPA's recent
literature review post-date these earlier reports
As described above I am quantitatively less certain that the chlorine effect is due to
chlorine.
3.3. What is your opinion about the potential implications of a chlorine effect on RBA for
predicting RBA in humans from animal bioassays (e.g., selection of appropriate animal
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model, estimation of composite RBA for a soil material containing a mix of congeners,
variability in congener composition of soils)?
I am much less certain of the chlorine effect than presented by EPA. I think the variability in
bioavailability between congeners may be equally due to soil type or concentration of
the congener administered. Therefore I believe that the potential implications are
minor, particularly since EPA is recommending using 100% bioavailability unless there is
site specific data.
3.4. EPA concludes that collection of site-specific data for estimating soil RBA is
recommended for the purpose of developing site-specific clean-up levels. Please
comment on the following:
a) importance of obtaining site-specific RBA data
This is a critical and appropriate conclusion
b) acceptance of an animal model for predicting RBA in humans
c) preferred animal model(s) and standard experimental protocol that would be
acceptable for determining the site-specific RBA
d) need for additional studies in rodent, swine, primate, or other species for
establishing a standard animal model protocol
Comments b, c and d are intertwined and I will respond to all three at once.
Clearly there is limited data on the species differences in oral bioavailability
between swine, rodents and primates for dioxins and further research is needed
to better determine the magnitude of these differences and which species is
best for this approach. The EPA make a reasonable conclusion that swine would
be a better model than rodents for actual bioavailability. However, I am less
certain this applies to relative bioavailability. AT this point I would take site
specific data on either swine or rodents, provided the dose dependent
pharmacokinetics was taken into account.
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3.5. EPA has described two approaches to estimate RBA for congener mixtures for use in site
risk assessment:
a) calculate the average RBA based on congener mass concentration in soil and
congener RBA (moss weighted RBA)
b) calculate the average RBA based on congener TEQ concentration and congener
RBA (TEQ weighted RBA)
What is your opinion on the relative merits and deficiencies in either approach, or on
alternative approaches to estimating RBA for use in risk assessment?
I would prefer to calculate the average RBA based on congener mass concentration in
the soil and congener RBA, then apply the TEF methodology on the bioavailable
chemical. If there is a chlorine effect on RBA, then the concentration of the chemicals
must be treated separately in the bioavailability estimates prior to TEQ evaluations.
Section 4 Uncertainties Identified in the Estimation of a Dioxin Soil RBA
4.1 Has EPA clearly described the major uncertainties attending its conclusions?
Yes
4.2 What is your opinion on the level of uncertainty in EPA's conclusions regarding RBA?
I think EPA provides a sound conclusion in that the use of 100% bioavailability is reasonable for
all soil types that do not have site-specific data on bioavailability. The EPA has provided
a clear description of the uncertainty and data limitations.
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CHARGE QUESTIONS to REVIEWERS
for Peer Review of Draft Report, "Bioavailability of Dioxins In Soil
and Soil-Like Materials: Literature Review and Data Analysis " July 2010.
Stephen M. Roberts, PhD
Section 1 General Charge Questions
1.1. Is the draft document Bioavailability of Dioxins in Soil and Soil-like Materials: Literature
Review and Data Analysis clearly written and logical?
Yes, the draft document is clearly written and well organized. The points made are
logical, for the most part, although a few may need to be reconsidered and others
clarified (as discussed in response to some of the charge questions below). The
Executive Summary faithfully captures the most important information from the main
body of the report. The use of appendices for more detailed information is appropriate.
1.2. Are the objectives of the literature review clearly stated?
Yes, the objectives are quite clear.
1.3 Has EPA objectively and clearly presented the rationale for its conclusions relevant to
estimating the relative bioavailability (RBA) of TCDD or other PCDD/Fs in soil?
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The rationale for each of the conclusions is clearly explained.
1.4 Do you agree with EPA's major conclusions regarding RBA of TCDD or other PCDD/Fs in
soil? EPA's major conclusions are as follows:
e) RBA in soil is less than 100%
I agree with the intent of this conclusion, although it could perhaps be better
stated. The conclusion is worded as if RBA is a single value, when the report
shows that it is a series of values for different congeners, and there is variability
associated with each (e.g., from the influence of soil conditions).
Also, the conclusion may be stated too decisively given the limited number of
soil samples for which RBA data are available. Something like, "Studies to date
suggest that RBAs for dioxin mixtures are consistently less than 100%" or "RBAs
measured in bioavailability studies were all less than 100%" might be easier to
defend as not overreaching the data.
f) data currently available are not sufficient to estimate a nationally-applicable
value for RBA for use in risk assessment (i.e., as an alternative to 100% or site-
specific values)
I strongly agree. The number and types of contaminated soil samples examined
to date are just too few to adequately capture the range of potential RBAs
among dioxin-contaminated sites nationally.
g) data currently available are not sufficient to determine the preferred animal
species for use as an animal bioassay for predicting soil RBA in humans
I agree. The report discusses considerations in determining the appropriate
animal model, but concludes appropriately that we don't have enough
information at present to make a confident choice.
h) site-specific data are recommended to develop site-specific cleanup levels.
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I agree. There is plenty of evidence, as summarized in this report and elsewhere,
that site-specific conditions such as the specific congeners present and soil
conditions can affect substantially the RBA(s). Without site-specific data,
determining the appropriate RBA to calculate site-specific cleanup levels would
be strictly guesswork.
If you disagree with any of the above conclusions, please comment on deficiencies in
the conclusions or alternative conclusions that could be derived from the data.
1.5. Are you aware of other critical studies that would make a substantial impact on EPA's
conclusions regarding RBA of TCDD and/or other PCDD/Fs?
I think that the critical studies have been captured in the report. I am not aware of any
other studies that would alter the conclusions of the report.
Section 2 Transparency and Clarity in the Selection of Key Data Sets for Relative
Bioavailability Analysis
2.1. Is EPA's approach for selecting key studies and data sets from the key studies
scientifically justified and clearly described?
The approach for selecting key studies is scientifically justified, and the most relevant
studies were chosen to be the focus of the analysis. The clarity of the process could be
improved, however. Specifically, there seems to be a disconnect between the literature
survey presented in Appendix A and the review of studies in Section 3. The literature
search product in Appendix A is broadly inclusive of a variety of types of studies that
might provide inference on the bioavailability of dioxin from soil. The main body of the
report focuses [appropriately in my opinion] on studies providing RBA estimates in
animal models, with little mention of other studies. The problem is that there is no link
between the two. If the RBA studies are the exclusive focus of the analysis, what was
the point of finding and listing other types of studies in the literature survey? If the
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other types of studies have something to offer, then why is there no discussion of their
contribution to the analysis? Additional discussion, however brief, of the thinking
involved in narrowing the focus to the nine studies presented in Section 3 would be
useful.
2.2. Are the chosen data sets adequate for estimating RBA values for each tested soil in each
of the studies?
Yes. Although some have limitations, all were adequate for providing an RBA estimate
for the tested soils.
2.3. Are the data relied upon for the estimation of RBA for each tested soil in each of the
studies, applied in a scientifically sound manner?
Yes, although there is a lack of transparency regarding the RBA values calculated for the
report from some of the studies. In discussing specific studies in Section 3.2, RBAs are
presented for some indicating that they were "calculated for this report" - apparently
meaning that they were derived by the EPA using data presented in the published study.
There is no description of how the data were interpreted and used to calculate these
RBAs, making it difficult to assess their scientific basis.
2.4. Please comment on deficiencies, substantial inadequacies of the selected studies and
data sets, and provide suggestions for existing or future studies that could inform the
assessment of soil RBA.
A number of assumptions are needed in order to calculate RBA using the standard
approach, including: 1) the doses are all in the linear pharmacokinetic range such that
concentrations in the body are proportional to the absorbed dose; 2) Other than
fraction of dose absorbed, the pharmacokinetics of the test and reference doses are the
same; and 3) the method of assessing the absorbed dose is reasonably complete, or at
least the test and reference doses are subject to the same type and degree of error. The
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challenge for estimating the RBA for dioxin congeners is trying to insure that these
assumptions are met, particularly the second two. The selected studies accomplished
this to varying extents -the more recent studies (e.g., Budinsky et al.) seemed
particularly aware of the need to address these points.
One study aspect that arguably deserves more discussion is the extent to which the
reference dose in the study reflects absorption under the conditions in which the
toxicity value was obtained. Admittedly, this is complicated somewhat by the use of
different data sets to generate various estimates of TCDD cancer potency, e.g., rodent
bioassays versus epi studies. However, the absorption of the reference dose is half of
the RBA calculation, and the various methods of administering the reference dose (i.e.,
in corn oil versus food) in the RBA studies are not necessarily equivalent.
As discussed in response to 3.2, studies are needed to explain differences between rats
and swine in terms of the effects of chlorination on absorption, and to determine to the
extent possible the best animal model for assessment of the RBAs for dioxin in soil.
There is also a need to greatly expand the suite of dioxin contaminated soils from which
RBA information is obtained. This will facilitate predictive model development.
Section 3 Use of Animal Bioassays to Estimate Relative Bioavailability
3.1. Are the animal models presented in this report appropriate for estimating RBA of TCDD
and other PCDD/Fs in soil? Please also comment on the criteria EPA has used to evaluate
the animal models:
d) similarities of physiology and anatomy of the animal model and human
gastrointestinal tract
e) similarity of distribution of absorbed PCDD/Fs in adipose tissue relative to liver
f) Ah receptor binding, CYP450 induction, and clearance of PCDD/Fs
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Both animal models presented in this report (rat and swine) are commonly used in
bioavailability studies and are appropriate for consideration. If the rat and swine
gave essentially the same results, an argument could be made for the rat based
simply upon cost. The limited data available for species comparison suggest that
they do not produce equivalent results, however, making it important to determine
which is the better predictor of RBA in humans. As the report points out, the
anatomy and physiology of the swine digestive tract is more similar to humans,
which is a point in favor of the swine. The report also states that the distribution of
absorbed PCDD/Fs is primarily to the adipose tissue in swine and humans, but the
liver in rats. This is important presumably because the greater the fraction of
absorbed dose distributing to the liver, the greater the opportunity for confounding
effects on RBA estimation due to changes/differences in metabolism and liver
protein binding (see below). This point should perhaps be reconsidered, or at least
examined more closely. The study of Budinsky et al. found distribution of most
congeners was primarily to adipose tissue rather than liver in swine, but the
opposite was found in the swine study of Wittsiepe et al., where distribution was
primarily to the liver. [This is not mentioned in the report.] The difference may be
due to the way congener concentrations in the tissues were expressed (per g tissue
in the Budinsky et al. report and per g lipid in the Wittsiepe et al. paper), but it is
difficult to tell without further analysis. Unfortunately, there are only two swine
studies and they measured tissue concentrations in two different ways; this isn't a
lot of information with which to make generalizations about species differences in
dioxin congener disposition.
On the matter of Ah receptor binding, CYP450 induction, and clearance of PCDD/Fs,
these are all confounding factors that affect RBA estimation. The report seems to
suggest that these are more of an issue for the rat than the swine, but it is not clear
why they don't apply to the swine as well. On page 31, there is discussion of AhR
affinity and the difference in affinity for TCDD between mouse and human AhR. This
is all well and good, but the issue here is rat versus swine versus human. This
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comparison is not well developed in the report with respect to AhR binding, CYP450
induction, or clearance of PCDD/Fs. With the information presented, it is hard to
conclude that one model is different from the other with respect to binding and
clearance by the liver.
3.2. What is your opinion of the observation that the effect of chlorine number on RBA is
different in swine and rats?
c) in swine, RBA appears to increase with increasing chlorination
d) in rats, RBA appears to decrease with increasing chlorination
Please comment on how this observation conforms or conflicts with information
regarding bioavailability provided by the National Academy of Science (NAS, 2006),
World Health Organization (Van den Berg et al. 2006), and U.S. EPA (2003). Note that
the swine studies (Budinsky et al., 2008; Wittsiepe et al., 2007) included in EPA's recent
literature review post-date these earlier reports.
As the report points out, previous conclusions by the NAS, WHO, and EPA regarding the
relationship between chlorine content and RBA were based upon rat data only, and
were not informed by the more recent swine studies. The observation here that the
relationship between chlorine number and RBA is fundamentally different between the
rat and swine raises the issue of determining the most appropriate animal model to a
high level. Until this difference between species can be explained and an animal model
with stronger scientific justification identified, progress in developing RBA values for site
evaluation will be stalled.
3.3. What is your opinion about the potential implications of a chlorine effect on RBA for
predicting RBA in humans from animal bioassays (e.g., selection of appropriate animal
model, estimation of composite RBA for a soil material containing a mix of congeners,
variability in congener composition of soils)?
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Although the direction of the effect isn't clear, there seems to be consensus among
studies examining RBAs of specific congeners that the extent of chlorination matters.
Consequently, it is logical to propose that different RBAs for different congeners, or
groups of congeners, be used to construct an overall RBA for a soil sample based upon
congener content. There is, however, a missing dimension mentioned in the report that
has not yet been explored, which is the influence of soil properties (e.g., organic carbon
content) on the congener-specific RBAs. There is ample evidence to suggest that soil
properties can affect the RBA (as cited in the report), but far too little data to establish
quantitative relationships between soil properties and congener-specific RBAs.
Developing those relationships will be a substantial undertaking.
3.4. EPA concludes that collection of site-specific data for estimating soil RBA is
recommended for the purpose of developing site-specific clean-up levels. Please
comment on the following:
e) importance of obtaining site-specific RBA data
f) acceptance of an animal model for predicting RBA in humans
g) preferred animal model(s) and standard experimental protocol that would be
acceptable for determining the site-specific RBA
h) need for additional studies in rodent, swine, primate, or other species for
establishing a standard animal model protocol
The report concludes that the RBA for dioxin is less than 100%, but too few soil samples
have been evaluated to determine an alternative, upper bound RBA value to use as a
national default. I agree with these conclusions. So the choice currently for calculation
of site cleanup levels is to either use a default RBA of 100% or develop site-specific RBA
data. This is basically a business decision, i.e., whether the refinement in cleanup levels
afforded by incorporating site-specific RBA data is worth the cost of obtaining those
data. If soil cleanup numbers are going to be adjusted based upon site-specific RBA
considerations, collection of site-specific data will be required [obviously]. Models to
predict site-specific dioxin RBAs based upon key site characteristics await development
of a body of research in which those characteristics are identified and their relationships
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with RBA quantified. It is difficult to predict how long it will take to develop that body of
research.
Until predictive models can be developed, site-specific dioxin RBA information will have
to be obtained empirically, i.e., through a study to estimate the dioxin RBA for soils at a
given site. There is some literature on in vitro extraction methods to estimate dioxin
bioavailability by measuring bioaccessibility, but acceptance of in vitro models for
regulatory purposes usually requires an extensive evaluation of performance with a
battery of soil samples for which RBA is known (e.g., as has been conducted for lead in
soil and is underway for arsenic). An adequate suite of soils for conducting this type of
evaluation for dioxin does not yet exist. This leaves, in the near term, in vivo studies
using animal models as the only reliable means of developing defensible, site-specific
RBA estimates.
Animal models are well accepted as providing useful information for predicting
bioavailability in humans. The question is which animal model is best suited for studying
comparative absorption of dioxin congeners from soil. This report raises that question,
but does not provide a clear answer. I agree that based upon anatomical and
physiological considerations, swine are more attractive than rats as a model. However,
additional studies are urgently needed to resolve the animal model issue, and to
establish a standard animal protocol. These studies could include limited experiments
in higher order species such as primates in order to help establish relevance of the
models to humans.
3.5. EPA has described two approaches to estimate RBA for congener mixtures for use in site
risk assessment:
c) calculate the average RBA based on congener mass concentration in soil and
congener RBA (moss weighted RBA)
d) calculate the average RBA based on congener TEQ concentration and congener
(TEQ weighted RBA)
A-17
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What is your opinion on the relative merits and deficiencies in either approach, or on
alternative approaches to estimating RBA for use in risk assessment?
The contribution of each congener toward risk is a function of both its RBA and TEQ.
The TEQ weighted RBA handles this in a somewhat more transparent manner, in my
opinion.
Section 4 Uncertainties Identified in the Estimation of a Dioxin Soil RBA
4.1 Has EPA clearly described the major uncertainties attending its conclusions?
The major uncertainties associated with its conclusions are clearly articulated.
Discussion of the uncertainties and limitations in the current body of literature on
estimation of dioxin RBA from soil is a major strength of this report.
4.2 What is your opinion on the level of uncertainty in EPA's conclusions regarding RBA?
The conclusions of the report highlight the uncertainties that exist in trying to estimate
dioxin RBA from soil. These uncertainties have not been overstated, and the
conclusions are sound, in my opinion.
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CHARGE QUESTIONS to REVIEWERS
for Peer Review of Draft Report, "Bioavailability ofDioxins In Soil
and Soil-Like Materials: Literature Review and Data Analysis " July 2010.
Michael E. Honeycutt, PhDSection 1 General Charge Questions
1.1. Is the draft document Bioavailability ofDioxins in Soil and Soil-like Materials: Literature
Review and Data Analysis clearly written and logical?
Overall, yes. The document is generally well-written and easy to follow. I have some
suggested edits.
• Page vii, line 174 - Don't start sentence with acronym; spell out
• Page vii - lines 187 through 195 refer to 13 test materials, but the bulleted text adds
up to 15 test materials.
• Page vii, line 227 - "octachloro" is misspelled
• Page vii, line 230 - "octachlorodibenzofurans" is misspelled
• Page 12, line 343 - Don't start sentence with acronym; spell out
• Page 13, line 376 - "groups means" should be either "group means" or "groups'
means"?
• Page 15, line 415 - "dose" should be added after "single"
• Page 16, line 445 - a semicolon should replace the period after "control"
• Page 17, line 483 - the comma after "27%" should be deleted
• Page 18, line 513 - a period is needed after "Appendix B"
• Section 3.2.4 should include soil concentrations. All the other study descriptions
include soil concentrations.
• In section 3.2.7, you might include a short description of the soil decontamination
process.
• Page 22, line 626 - octachloro is misspelled.
A-19
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• Page 23, line 661 - delete one comma after "materials"
• Page 23, line 661 - Run on sentence. End sentence after "included" and capitalize
"Most"
• Page 23, line 666 - Delete sentence starting with "Relative bioavailability...." It is
already defined and this study uses the same definition of relative bioavailability.
• Page 23, line 669 - Don't start sentence with acronym; spell out.
• Page 24, lines 670 and 671 - Don't start sentence with acronym; spell out.
• Page 25 - Lines 686 and 694 refer to 13 test materials, but the bulleted text adds up
to 15 test materials.
• Page 26, line 719 - "12.1" should be "12.2"
• Page 25, line 722 - "R2=0.32" should be "R2=0.34"
• Page 27, line 759 - ", respectively." should be added after "26.6%"
• Page 28, line 770 - add "several" before "reasons"?
• Page 28, line 776 and Page 31, line 861 refer to Connor and Aylward (2006) and
Flaveny et al. (2010) with no context. The context of the references are explained
later in bullet 3 of section 4.2. It would be helpful to either add context the first two
times the references are mention or add "(explained later)".
• Page 28, line 787 - "18.3" should be "-18.3"
• Page 28, line 790 - "-13.9" should be "-13.07" and "R2=0.37" should be "R2=0.35"
• Page 28 - lines 791 and 793 mention seven test materials in Table 3, but Table 3 only
contains five test materials
• Page 29, line 821 - "(TM2)" should be "(TM1)"
• Page 30, line 833 - delete "it" from after "doses"
• Page 30, line 853 - Run on sentence. End sentence after "PCCD/Fs" or change
comma to semicolon.
• Page 30, line 857 - delete comma after "estimates"
• Page 31, line 867 - add a comma after "review"
• Page 31, line 868 - add "does" after "AhR"
• Page 34, line 967 - "more" should be "less"
• Page 34, line 975 - octachloro is misspelled
• Page 35, line 995 - delete ", however,"
• Page 35, line 1005 - add "do" either in front of or behind "rodent models"
• Page 38, line 1081 - don't begin sentence with acronym
• Page 38, line 1084 - delete the comma after "reports"
• Page 39, line 1123 - delete the comma after "problematic"
• Tables 2 and 3 - add units; (%) after descriptors in left-hand column
1.2. Are the objectives of the literature review clearly stated?
Yes.
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1.3 Has EPA objectively and clearly presented the rationale for its conclusions relevant to
estimating the relative bioavailability (RBA) of TCDD or other PCDD/Fs in soil?
Yes. Clearly, dioxins and furans are less than 100% bioavailable, but data are not
adequate to derive a nationally-applicable RBA. I absolutely agree with the conclusions.
1.4 Do you agree with EPA's major conclusions regarding RBA of TCDD or other PCDD/Fs in
soil? EPA's major conclusions are as follows:
i) RBA in soil is less than 100%
Yes. I absolutely agree with this statement.
j) data currently available are not sufficient to estimate a nationally-applicable
value for RBA for use in risk assessment (i.e., as an alternative to 100% or site-
specific values)
Yes. I absolutely agree.
k) data currently available are not sufficient to determine the preferred animal
species for use as an animal bioassay for predicting soil RBA in humans
I disagree with this statement. Swine are the preferred animal model. The fact
that rats yield different results does not mean that swine are not the preferred
animal model. Species differences are the norm, not the exception, in
toxicology.
I) site-specific data are recommended to develop site-specific cleanup levels.
I agree with this statement. EPA should develop guidance on developing site-
specific data.
If you disagree with any of the above conclusions, please comment on deficiencies in
the conclusions or alternative conclusions that could be derived from the data.
A-21
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1.5. Are you aware of other critical studies that would make a substantial impact on EPA's
conclusions regarding RBA of TCDD and/or other PCDD/Fs?
No. Interestingly, Kimbrough et al (2010) published a similar review in Regulatory
Toxicology and Pharmacology 57:43-54. The Kimbrough review is substantively very
similar to the current EPA review, though the Kimbrough review did not attempt to
determine a nationwide RBA.
Section 2 Transparency and Clarity in the Selection of Key Data Sets for Relative
Bioavailability Analysis
2.1. Is EPA's approach for selecting key studies and data sets from the key studies
scientifically justified and clearly described?
Yes.
2.2. Are the chosen data sets adequate for estimating RBA values for each tested soil in each
of the studies?
Yes.
2.3. Are the data relied upon for the estimation of RBA for each tested soil in each of the
studies, applied in a scientifically sound manner?
Yes.
2.4. Please comment on deficiencies, substantial inadequacies of the selected studies and
data sets, and provide suggestions for existing or future studies that could inform the
assessment of soil RBA.
A-22
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The studies selected for review in this document are scientifically sound. Future studies
should focus on soil characteristics that influence RBA.
Section 3 Use of Animal Bioassays to Estimate Relative Bioavailability
3.1. Are the animal models presented in this report appropriate for estimating RBA of TCDD
and other PCDD/Fs in soil?
Yes.
Please also comment on the criteria EPA has used to evaluate the animal models:
g) similarities of physiology and anatomy of the animal model and human
gastrointestinal tract
This is one of the most important factors. Differences in anatomy and physiology
will have a significant downstream effect on subsequent absorption and distribution,
which in turn will have a significant downstream effect on cellular, intracellular,
metabolic, and elimination processes.
h) similarity of distribution of absorbed PCDD/Fs in adipose tissue relative to liver
This factor is just as, or perhaps nearly as, important as similarities in physiology and
anatomy. Differences in distribution will lead to differences in cellular, intracellular,
metabolic, and elimination processes.
i) Ah receptor binding, CYP450 induction, and clearance of PCDD/Fs
The upstream factors of species differences in absorption and distribution make
these the least important factors.
3.2. What is your opinion of the observation that the effect of chlorine number on RBA is
different in swine and rats?
A-23
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e) in swine, RBA appears to increase with increasing chlorination
This makes perfect sense. This same phenomenon occurs in aquatic species.
f) in rats, RBA appears to decrease with increasing chlorination
This illustrates why rats are not a good animal model for humans and why swine are.
Please comment on how this observation conforms or conflicts with information
regarding bioavailability provided by the National Academy of Science (NAS, 2006),
World Health Organization (Van den Berg et al. 2006), and U.S. EPA (2003). Note that
the swine studies (Budinsky et al., 2008; Wittseipe et al., 2007) included in EPA's recent
literature review post-date these earlier reports.
Neither NAS, 2006, USEPA, 2003, nor Van den Bert, et al, 2006 appear to directly
address the issue of differences in RBA among species as it pertains to risk assessment.
Nevertheless, the present document does not conflict with the above references.
3.3. What is your opinion about the potential implications of a chlorine effect on RBA for
predicting RBA in humans from animal bioassays (e.g., selection of appropriate animal
model, estimation of composite RBA for a soil material containing a mix of congeners,
variability in congener composition of soils)?
The effect of chlorination on RBA can be dealt with. Using the appropriate animal
model (swine) for both the native soil and the appropriate solvent will control for the
effect of degree of chlorination.
3.4. EPA concludes that collection of site-specific data for estimating soil RBA is
recommended for the purpose of developing site-specific clean-up levels. Please
comment on the following:
i) importance of obtaining site-specific RBA data
A-24
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With EPA proposed new dioxin toxicity factors and PRGs, obtaining site-specific data
will be very important since background levels of dioxins will likely be unacceptably
high. Obtaining site-specific RBA data will be very important in delineating extent of
contamination at a remediation site, as well as in deciding a remedy.
j) acceptance of an animal model for predicting RBA in humans
Swine is the best animal model for humans. A swine study is more expensive, but it
is also more appropriate.
k) preferred animal model(s) and standard experimental protocol that would be
acceptable for determining the site-specific RBA
Swine is the best animal model. I am not aware of a standard experimental protocol
that is acceptable to EPA. EPA should develop one.
I) need for additional studies in rodent, swine, primate, or other species for
establishing a standard animal model protocol.
Studies could be conducted better define an appropriate swine RBA study (dosing
method, dose rate, study length, etc.).
3.5. EPA has described two approaches to estimate RBA for congener mixtures for use in site
risk assessment:
e) calculate the average RBA based on congener mass concentration in soil and
congener RBA (moss weighted RBA)
f) calculate the average RBA based on congener TEQ concentration and congener
RBk(TEQ weighted RBA)
What is your opinion on the relative merits and deficiencies in either approach, or on
alternative approaches to estimating RBA for use in risk assessment?
Van den Bert, et a I, 2006 recommend the mass-weighted RBA approach as "preferable".
I have no strong opinion one way or the other.
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Section 4 Uncertainties Identified in the Estimation of a Dioxin Soil RBA
4.1 Has EPA clearly described the major uncertainties attending its conclusions?
Yes. I can't think of anything else that should be addressed.
4.2 What is your opinion on the level of uncertainty in EPA's conclusions regarding RBA?
EPA elucidated the appropriate level of uncertainty in the document.
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Appendix B - Peer Review Materials
B-l
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DRAFT REPORT: BIO A VAILABILITY OF DIOXINS IN SOIL AND SOIL-LIKE
MATERIALS
July 2010
External Peer Review Statement of Work
Background and Overview
Environmental Management Support, Inc. (EMS), under contract EP-W-07-037 with the
Environmental Protection Agency's (EPA) Office of Solid Waste and Emergency Response, has
been asked to obtain external, independent reviews of the draft report, Bioavailability ofDioxins
in Soil and Soil-Like Materials.
The purpose of this peer review is to identify any technical problems, omissions, or inconsisten-
cies in the draft report, and to obtain expert opinion as to the usefulness and appropriateness of
report for its stated objectives. Your comments and recommendations will be used to revise the
draft report so that the final version reflects sound technical information and guidance.
General Instructions
Your responsibilities are as follows:
• Review and execute the Peer Review Conflict of Interest Certification, and return it to
EMS as soon as possible (a digital signature or scanned signature is acceptable).
• Keep track of the number of hours you spend on this peer review (and report them when
you submit your invoice).
• Review the draft report in light of the charge questions at the end of this SOW and your
personal experience and expertise.
• Please tie your comments as much as possible to the product, page, section, and line
number(s) so we will be able to consider your comment in context.
• If you mention any additional references in your comments, please provide an electronic
copy of those references, if possible, a full citation, or Internet address of where they
reside.
E-mail your comments to EMS's Peer Review Manager (Diane Dopkin,
diane.dopkin@emsus.com, 301-589-5318 ext. 38), on or before August 10, 2010. You may
submit either a narrative sequence of comments tied to the document line number or else an
annotated pdf copy of the report (using the Text Edits and Insert Comments modes), plus your
specific responses to the charge questions below and any additional comments by e-mail.
We suggest you consider a number of points, covered below, but we rely on your expertise and
experience to cover any aspect of report.
CHARGE QUESTIONS TO REVIEWERS
B-2
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Section 1 General Charge Questions
1.1. Is the draft document Bioavailability of Dioxins in Soils and Soil-like Materials
clearly written and logical?
1.2. Were the stated objectives clearly worded? Has EPA presented its rationale for
assigning a relative bioavailability (default gastrointestinal absorption fraction) value
objectively and clearly?
1.3. Are you aware of other critical studies that would make a substantial impact on the
conclusions formed for assigning a default relative bioavailability (RBA) value for
tetrachloro-p-dibenzodioxin (TCDD) and/or other polychlorinated dibenzodioxins and
dibenzofurans (PCDD/Fs)?
Section 2 Transparency and Clarity in the Selection of Key Data Sets for Relative
Bioavailability Analysis
2.1.a Is EPA's approach for selecting data sets from the key animal bioassays identified for
RBA scientifically justified and clearly described?
2.1 .b Is the document transparent in the rationale for selecting the data sets used to assign a
bioavailability factor?
2.2. Are the primary studies scientifically justified and clearly described?
2.3.a Are the data relied upon for the estimation of relative bioavailability applied in a
scientifically sound manner?
2.3.b If not, please identify and provide a rationale for alternative approaches.
2.4.a Are the chosen data sets adequate for the determination of a default RBA estimate?
2.4.b If not, please comment on vagaries, substantial inadequacies, and suggestions for
existing or future studies that will meet your experiment criteria.
B-3
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Section 3 The Use of Swine or/and Rodent Data to Estimate a Relative Bioavailability
Factor
3.1 Swine and monkey models were used by EPA to establish RBA and 95% upper
control limit (UCL) of arsenic in soil. Murine models were not considered. Monkey
studies of dioxin RBA were not identified. Using precedent as the basis for selecting
an appropriate animal model for estimating dioxin RBA in soil, is it appropriate to
exclude murine RBA data a priori^ Please comment.
3.2 Murine models use liver dioxin levels as a surrogate for intestinal absorption fraction.
After accepting the following premises: a.) mouse aryl hydrocarbon receptor (AhR)
binds TCDD with a 10-fold greater affinity than humans; b.) rat liver enzymes are
induced at body burden levels an order of magnitude less than humans; and c) for
chlorinated compounds like PCBs, bioaccumulation increases as degree of
chlorination increases, please comment on the following question.
3.2.a Can TCDD in the rat liver be considered a reliable index for estimating oral
bioavailability?
3.3 The observation that congeners do not have the same RBA values as TCDD has
important implications for the application of RBA values in dioxin risk assessment.
A critical contention for using swine data and excluding murine data is the response
to increasing chlorination of dioxin congeners/homologues, where RBA increases in
the swine model and decreases in the rat model. The marked difference for the
relationship between congener chlorine content and RBA based on swine and rat
assays present a conundrum and no data have been developed to explain the
observations.
3.3.a Please comment.
3.3.b Can swine and rat data be combined reliably to estimate a unified dioxin soil RBA.
3.3.c What criteria did you use to provide a positive or negative response?
3.4.a Given that swine and rat dioxin soil RBA data are divergent with respect to
chlorination of congeners, will it be possible to use one species or the other or both to assign
congener specific RBA values?
B-4
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3.4.b Does the stated preference for swine studies to determine KB A for humans have
scientific merit?
3.5. EPA guidance recommends that even in cases where sufficient data exist to support
default medium-specific absorption factors for a chemical, site-specific data
collection may also be important. Please comment on:
3.5.a the future consideration for the importance of obtaining site-specific RBA data.
3.5.b the acceptance of animal model dioxin soil RBA as a surrogate for human RBA.
3.5.c the importance of securing funding for additional swine experiments and monkey
studies for dioxin soil RBA determinations, and
3.5.d an animal model that would be acceptable for determining the site-specific value.
Section 4. Uncertainties Identified in the Estimation of a Dioxin Soil RBA
4.1 Please comment on whether EPA has clearly described the major qualitative
uncertainties.
4.2 About 70 data sets were incorporated into the estimate of arsenic RBA; this review,
for estimate, relied on six that were selected for the quality and relevance of
information provided in each study. In most circumstances, substantial uncertainty
would validate the decision to combine RBA estimates from both swine and murine
studies.
Given the restricted data set in both species used to calculate RBA would you opine
that uncertainty is acceptable to posit a value using swine data alone?
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DRAFT 7 REPORT
BIO AVAILABILITY OF DIOXINS IN SOIL
AND SOIL-LIKE MATERIALS
Prepared for:
U.S. Environmental Protection Agency, Office of Superfund Remediation and
Technology Innovation, Environmental Response Team - West
Las Vegas, NV 89119
Bill Albrecht, Work Assignment Manager, SERAS-067
Prepared by:
SRC, Inc.
Chemical, Biological, and Environmental Center
6502 Round Pond Road
North Syracuse, NY 13212
August 13, 2010
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DRAFT 7-Do Not Cite, Quote, or Distribute - DRAFT 7
TABLE OF CONTENTS
LIST OF TABLES ix
LIST OF FIGURES ix
LIST OF APPENDICES ix
ABBREVIATIONS AND ACRONYMS x
EXECUTIVE SUMMARY xi
Objectives xi
Results xii
Conclusions xv
1.0 INTRODUCTION 16
1.1 Background 16
2.0 METHODS 17
2.1 Literature Search Strategy 17
2.2 Data Analyses 17
3.0 RESULTS 20
3.1 General Features of RBA Studies 20
3.2 Summary of Studies 20
3.2.1 Bonaccorsi et al. (1984) Rabbit Study 21
3.2.2 Budinsky et al. (2008) Swine and Rat Studies 21
3.2.3 Finley et al. (2009) Rat Study 23
3.2.4 Lucieretal. (1986) Rat Study 24
3.2.5 McConnell etal. (1984) Guinea Pig Study 24
3.2.6 Shu etal. (1988) Rat Study 25
3.2.7 Umbreitetal. (1986) Guinea Pig Study 26
3.3.8 Wendling et al. (1989) Guinea Pig Study 27
Page vii of 52
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3.2.9 Wittsiepe et al. (2007) Swine Study 28
4.0 DISCUSSION 30
4.1 Analysis for Multiple Congener KB A Estimates 31
4.1.1 Multiple Congener KB A Estimates in Swine 31
4.1.2 Multiple Congener KB A Estimates in Rats 33
4.2 Comparison of Swine and Rat KB A Estimates 34
4.3 Influence of Dose on RBA Estimates for 2,3,7,8-TCDD 36
4.4 Implications for Risk Assessment 37
5.0 SUMMARY AND CONCLUSIONS 39
5.1 Summary of Findings 39
5.2 Uncertainties in RBA Estimates 42
5.3 Conclusions 44
6.0 REFERENCES 46
Page viii of 52
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DRAFT 7-Do Not Cite, Quote, or Distribute - DRAFT 7
LIST OF TABLES
Table 1. Summary of KB A Studies of Dioxins in Soil 49
Table 2. Summary Statistics for Multiple Congener KB A Estimates in Swine 52
Table 3. Summary Statistics for Multiple Congener KB A Estimates in Rats 53
Table 4. Comparison of KB A Estimates for Swine and Rats in Identical Test Materials 54
LIST OF FIGURES
Figure 1. Relationship between congener chlorine content (mole chlorine/mole congener) and
RBA based on swine assays of three test materials (Budinsky et al. 2008, BU08; Wittsiepe et al.
2007, WI07) 55
Figure 2. Relationship between congener chlorine content (mole chlorine/mole congener) and
RBA based on rat assays of seven test materials (Budinsky et al. 2008, BU08; Finley et al. 2009,
FI09) 56
Figure 3. Relationship between 2,3,7,8-TCDD dose (pg/kg bw/day) and RBA based on swine,
rat, and rabbit assays of six test materials (Bonaccorsi et al. 1984; Budinsky et al. 2008; Lucier et
al. 1986; Shu etal. 1988; Wittsiepe etal. 2007) 57
LIST OF APPENDICES
Appendix A - Literature Search Product: Bioavailability of Dioxins in Soil A-1
Appendix B - RBA Data B-l
Page ix of 52
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DRAFT 7-Do Not Cite, Quote, or Distribute - DRAFT 7
ABBREVIATIONS AND ACRONYMS
ABA absolute bioavailability
AhR aryl hydrocarbon receptor
(3 beta regression coefficient (i.e., regression slope)
bw body weight
CI confidence interval
CR cancer risk
CSF cancer slope factor
CYP450 cytochrome P450
GC/MS gas chromatography/mass spectrometry
HpCD heptachloro-p-dibenzodioxin
HpCF heptachlorodibenzofurn
HxCD hexachloro-p-dibenzodioxin
kg kilogram
MAX maximum
MED median
MIN minimum
mL milliliter
NA not available
ND no data
ng nanogram
NR not reported
OCDD octochloro-p-dibenzodioxin
OCDF octochlorodibenzofuran
PCDD polychlorinated dibenzo-p-dioxin
PCDF polychlorinated dibenzofuran
PeCD pentachloro-p-dibenzodioxin
pg picogram
PeCF pentachlorodibenzofurn
ppb part per billion
ppm part per million
ppt part per trillion
RAGS Risk Assessment Guidance for Superfund
RBA relative bioavailability
RfD reference dose
RM reference material
SD standard deviation
SE standard error
TCDD tetrachloro-p-dibenzodioxin
TCDF tetrachlorodibenzofurn
TEF toxic equivalence factor
TEQ toxic equivalent
TM test material
(im micron
USEPA U.S. Environmental Protection Agency
WHO World Health Organization
2,4,5-T 2,4,5-trichlorophenoxyacetic acid
Page x of 52
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EXECUTIVE SUMMARY
The Risk Assessment Guidance for Superfund (RAGS) Part A (USEPA 1989) discusses making
adjustments to Superfund site-specific risk assessments when the medium of exposure in an
exposure assessment differs from the medium of exposure assumed by the toxicity value (cancer
slope factor, reference dose value, etc.) based upon site-specific bioavailability data. An
important consideration in assessing risks from exposures to dioxin in soil is whether an
adjustment is needed in the application of the cancer slope factor (CSF) and/or chronic reference
dose (RfD) for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD). This adjustment would account
for differences in the bioavailability of TCDD (and lexicologically related polychlorinated
dibenzo-p-dioxins [PCDD] and polychlorinated dibenzofuran congeners [PCDF]) in soil and in
the test medium used in the critical study(s) on which the CSF and/or RfD were based (e.g.,
dietary exposure vs. exposure to soil). An adjustment would be considered appropriate if
evidence were sufficient to indicate that the relative bioavailability (RBA) of the PCDD/F
mixture in soil was less than 100%. This report presents a summary of the published literature
and analysis of the available data regarding RBA of PCDD/F in soil.
Objectives
The principal objectives of this literature review and data analysis are as follows:
1. Identify and summarize published literature potentially relevant to estimating RBA of
PCDD/Fs in soil. Select studies that meet predetermined quality considerations.
2. Evaluate data contained in this literature to determine if they are adequate and sufficient
to conclude that RBA for PCDD/Fs RBA in soil is less than 100%.
3. Use these data, if adequate and sufficient, to calculate a quantitative central tendency and
upper bound estimate of RBA that can be applied when developing site-specific cleanup
levels for dioxin in soil.
Page xi of 52
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Results
Published literature potentially relevant to estimating RBA of PCDD/F in soil was identified,
reviewed, and summarized. A total of nine studies were identified. Pertinent data from six of
these studies were extracted and used to derive estimate(s) of RBA. RBA estimates for all test
materials were less than 100%.
The six studies were selected based on the quality and relevance of information provided in each
study (Bonaccorsi et al. 1984; Budinsky et al. 2008; Finley et al. 2009; Lucier et al. 1986; Shu et
al. 1988; Wittsiepe et al. 2007). All selected studies provided RBA estimates in test materials
consisting of soil contaminated with dioxins in situ. Studies of spiked soil materials were not
included in this analysis based on information suggesting that aging of contaminated soil may
decrease the bioavailability of dioxins in soil (Poiger and Schlatter 1980; Ruby et al. 2002;
Umbreit et al. 1986). Studies that administered dose levels of dioxins that were clearly toxic
were likewise not included in this analysis (McConnell et al. 1984; Umbreit et al. 1986;
Wendling et al. 1989).
The six studies selected for further analysis provided RBA estimates for 13 test materials (soil
from recognized dioxin impacted sites) based on assays in the following experimental models:
• Swine: 3 test materials (Budinsky et al. 2008; Wittsiepe et al. 2007);
• Rats: 11 test materials (Budinsky et al. 2008; Finley et al. 2009; Lucier et al. 1986; Shu et
al. 1988); and
• Rabbit: 1 test material (Bonaccorsi et al. 1984).
Only 2 of the 13 test materials were assayed in both swine and rats (Budinsky et al. 2008). Three
of the 6 studies estimated RBA for multiple congeners with varying chlorination in 8 different
test materials (Budinsky et al. 2008; Finley et al. 2009; Wittsiepe et al. 2007). The remaining
studies estimated RBA for 2,3,7,8-TCDD only.
Page xii of 52
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Collectively, analyses of published KB A estimates for PCDD/F in soil support the following
conclusions:
1. KB A for PCDD/F mixtures in soils assayed in swine and rats are less than 100%.
2. KBA varies with congener chlorination. The direction of the relationship (i.e., positive or
negative slope) is not the same when estimated based on data from swine or rat assays
(Budinsky et al. 2008; Finley et al. 2009; Wittsiepe et al. 2007). Data from swine assays
indicate an increase in KBA with increasing chlorine content (Budinsky et al. 2008;
Wittsiepe et al. 2007), whereas, data from rat assays indicate a decrease in KBA with
increasing chlorination (Budinsky et al. 2008; Finley et al. 2009). These differences
suggest substantially different KBA estimates may be obtained depending on the animal
model used.
The National Academy of Sciences (NAS 2006), the World Health Organization (Van
den Berg et. al. 2006), other international committees and organizations, the U.S.
Environmental Protection Agency (USEPA 2003), and other state agencies (e.g.,
WASDE 2007) have recognized that soil will influence the bioavailability of mixtures of
PCCD/Fs and have concluded that higher chlorinated congeners tend to be less
bioavailable than the more chlorinated congeners. However, observations and analyses
reported here suggest that the effect of chlorination on the KBA of dioxins in soil may be
different for different animal models, as shown in the recently reported swine assays.
3. The dependence of KB As on congener chlorination suggests soil KBA will depend on the
congener composition of the soil (as well as the bioassay used to estimate KBA).
Congeners with different levels of chlorination result in different composite KBA
averages for soil when calculated based on total congener mass or 2,3,7,8-TCDD toxicity
equivalents (TEQ). For example, based on the swine KBA assays, octochloro-p-
dibenzodioxins (OCDD; 8 chlorines substituted on 8 available positions on the carbons of
the benzene rings on either side of the central diheterabenzene, or "CIS") and
octochlorodibenzofurans (OCDFs, CIS) will have a higher KBA than lower chlorine
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content congeners. Therefore, for soil highly enriched with OCDDs and OCDFs (i.e.,
higher RBA and lower toxic equivalence factor (TEF)), the RBA based on total congener
mass will be higher than the RBA based on total TEQ. If, on the other hand, the soil
RBA is based on rat RBA assays, high enrichment of OCDDs and OCDFs would result in
higher TEQ RBAs compared to RBAs for total congener mass.
4. The influence of abiotic constituents, compound aging, and other associated soil factors
on RBA of dioxin in soil has not been evaluated systematically. Bioavailability appears
to decrease with aging based on comparisons of laboratory-spiked soil and soil
contaminated in situ (Poiger and Schlatter 1980; Umbreit et al. 1986) and is lower when
administered as a mixture of activated carbon compared to an aqueous suspension (Poiger
and Schlatter 1980). The latter observation suggests that organic carbon content may
contribute to a decrease in dioxin bioavailability from soil.
5. Although, RBA for dioxins in the soils evaluated in these studies is less than 100%,
estimating a representative range or upper bound value for RBA from these data is
problematic because of the limited number of estimates, the confounding effects of
congener chlorination on RBA, and differences in the estimates based on swine and rat
assays.
In the swine assays, the total congener mass RBAs average 38% and range up to 50%;
the total TEQ RBAs average 28% and range up to 33%. A statistically robust description
of the distribution of the RBA values cannot be estimated from these swine studies, as
they consist only of three test materials. Nevertheless, were adequate data available from
swine assays, reliance on swine RBA estimates, as opposed to rat RBA estimates, would
be appealing for several reasons. Similarities between the physiology and anatomy of the
swine and human gastrointestinal tracts make swine a preferable model for predicting
RBA in humans than rodent models (USEPA 2007). Swine and rats also differ in the
distribution of absorbed PCCD/Fs. Similar to humans, swine accumulate higher levels in
adipose tissue relative to liver, whereas, the distribution in rats tends to show the opposite
trend (Budinsky et al. 2008; Thoma et al. 1989, 1990). Moreover, using rat liver dioxin
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burden as a biomarker may have other implications related to species differences in
binding to the aryl hydrocarbon receptor (AhR) and induction of cytochrome P450
(CYP450), the major route of metabolic clearance of PCDD/Fs (Budinsky et al. 2008;
Connor and Aylward 2006; Finley et al. 2009; Flaveny et al. 2010).
In the rat studies, the total congener mass KB As average 29% and range up to 68%; the
total TEQ KB As average 41% and range up to 64%. While the rat studies offer a larger
data set for analysis, these data are still considered insufficient for representing the
variability in KBA at U.S. sites having a range of soil characteristics and congener mixes.
Also, the uncertainty regarding the extrapolation of KB A estimates in rodents to humans
is considered too large. A contributing factor to this uncertainty is a lack of mechanistic
understanding of the differences in KBA estimates obtained from swine and rats.
Conclusions
1. Currently available information suggests that KBA of dioxin in soils can be expected to
be less than 100%.
2. Available estimates of soil dioxin KBA are not adequate and sufficient to estimate a value
for KBA for use in risk assessment as an alternative to 100% or site-specific values.
3. A preferred animal model or bioassay protocol has not been established for predicting
soil KBA in humans.
4. Until an applicable value for dioxin KBA can be established, collection of site-specific
data on KBA is recommended to inform cleanup decisions.
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1.0 INTRODUCTION
1.1 Background
The Risk Assessment Guidance for Superfund (RAGS) Part A (USEPA 1989) discusses making
adjustments to Superfund site-specific risk assessments when the medium of exposure in an
exposure assessment differs from the medium of exposure assumed by the toxicity value (cancer
slope factor, reference dose value, etc.) based upon site-specific bioavailability data. An
important consideration in assessing risks from exposures to dioxin in soil is whether an
adjustment is needed in the application of the cancer slope factor (CSF) and/or chronic reference
dose (RfD) for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD). This adjustment would account
for differences in the bioavailability of TCDD (and lexicologically related polychlorinated
dibenzo-p-dioxins [PCDD] and polychlorinated dibenzofuran congeners [PCDF]) in soil and in
the test medium used in the critical study(s) on which the CSF and/or RfD were based (e.g.,
dietary exposure vs. exposure to soil). An adjustment would be considered appropriate if
evidence were sufficient to indicate that the relative bioavailability (RBA) of the PCDD/F
mixture in soil was less than 100%. This report presents a review of the published literature and
analysis of the available data regarding RBA of PCDD/F in soil.
The principal objectives of this literature review and data analysis are as follows:
4. Identify and summarize published literature potentially relevant to estimating RBA of
PCDD/Fs in soil. Select studies that meet predetermined quality considerations.
5. Evaluate data contained in this literature to determine if they are adequate and sufficient
to conclude that RBA for PCDD/Fs RBA in soil is less than 100%.
6. Use these data, if adequate and sufficient, to calculate a quantitative central tendency and
upper bound estimate of RBA that can be applied when developing site-specific cleanup
levels for dioxin in soil.
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2.0 METHODS
2.1 Literature Search Strategy
The following approach was used to identify literature pertinent to the topic of bioavailability of
PCDD/F in soil:
• Literature published before 1998 was identified from the text and bibliography of the
current (199&)ATSDR Toxicological Profile for Chlorinated Dibenzo-p-Dioxins.
• Literature published subsequent to 1998 was identified based on results of a dioxin
literature evaluation conducted in 2008 (for the period 1998-2008).
• Literature published subsequent to 2008 was identified from a de novo bibliographic
search (e.g., MEDLINE/TOXLINE) conducted for the period 2008-present. The search
focused on relevant literature (e.g., absorption, bioavailability).
• As pertinent literature from the above searches was identified and retrieved, the
references in these reports were tree-searched to identify additional pertinent literature.
A preliminary description of the search results (prepared before initiation of literature retrieval)
was developed and is included in Appendix A of this report.
2.2 Data Analyses
KB A values were calculated, if not reported, based on reported group mean estimates for
administered dose and liver PCDD/F levels. The general form of the calculations used to
estimate RBA is given in Equations 1 and 2:
RBA = n!L Eq. (1)
H V '
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ABA = AF = — • —— Eq. (2)
ED (- M V '
where ABAxM and ABA^M are absolute bioavailability for the test material (e.g., soil) and
reference material (e.g., dioxin in corn oil), respectively; AFis the absorbed fraction of the dose;
ID and ED are the internal dose and external dose, respectively, of the test or reference material;
and EF is the fraction of the absorbed dose eliminated by metabolism and excretion. In most
studies, the internal dose metric (ID) was liver PCDD/F burden; however, the sum of liver and
adipose burdens were also used in some studies (Budinsky et al. 2008; Wittsiepe et al. 2007).
Although the elimination fraction (EF) appears in the expression for absolute bioavailability
(ABA in Equation 2), it does not need to be considered in the calculation of RBA (Equation 1), as
long as elimination kinetics are similar for the PCDD/F absorbed from the test material and
reference materials (i.e., EFTM=EFRM). However, if EFpM were to exceed EFrM, the ID/ED ratio
will underestimate RBA. The validity of the assumption of equal elimination kinetics of the test
and reference materials is an important issue in the estimation of RBA for PCDD/F congeners,
because the metabolic elimination of PCDD/Fs is dose-dependent. Dose-dependency derives
from the induction of cytochrome P450 (CYP450), which is the primary mechanism for
metabolic elimination of PCDD/Fs. This issue is addressed further in the data analysis sections
of this report.
In most studies considered in this report, elimination fractions were not estimated. As a result,
reported estimates for the ratio ID/ED would be expected to underestimate absolute
bioavailability to varying degrees depending on the elimination kinetics of the specific PCDD/F
congeners considered. In this analysis, the ID/ED ratios for the test and reference materials were
used in the calculation of RBA; no attempt was made to estimate absolute bioavailability.
For multiple congener studies, RBA was calculated based on congener mass as well as 2,3,7,8-
TCDD (TCDD) toxic equivalents (TEQ), where the toxic equivalency factor (TEF) values were
assigned to each congener based on Van den Berg (2006). Only the groups means for dose and
tissue levels were reported; therefore, mean congener mass and TEQ RBAs were calculated as
weighted congener means, with weights assigned based on congener or TEQ dose (Equations 3
and 4):
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Mass - weighted RBA = £ MassDo5et • RBAi Eq. (3)
TEQ - weighted RBA = £ TEQDose,- • RBAi Eq. (4)
where MassDoset and TEQDoset are the mass and TEQ dose for congener /', respectively and
RBAj is the calculated or reported RBA for congener /'.
Congener and TEQ doses (per kg body weight per day; kg bw/day) were either reported or
calculated based on reported data on congener concentrations in the test soil, soil doses, and
reported body weights of the test animals. The midpoint of the range was used in the dose
calculation if body weight was reported as a range.
All data analyses were conducted using either Microsoft Excel 2007 (Microsoft) or
STATGRAPHICS Centurion XV (v 15.2.06, StatPoint, Inc.).
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3.0 RESULTS
3.1 General Features of KB A Studies
Nine studies providing KB A estimates of PCDD/F in soil were identified in the literature review.
A tabular summary of each study is provided in Table 1 and more detailed summaries follow in
Section 3.2. The studies include estimates based on assays in swine (Budinsky et al. 2008;
Wittsiepe et al. 2007), rats (Budinsky et al. 2008; Finley et al. 2009; Lucier et al. 1986; Shu et al.
1988), rabbits (Bonaccorsi et al. 1984), and guinea pigs (Umbreit et al. 1986; Wendling et al.
1989). Three of the studies estimated RBA for multiple congeners (Budinsky et al. 2008; Finley
et al. 2009; Wittsiepe et al. 2007); the remaining studies estimated RBA for 2,3,7,8-TCDD only.
The soil test materials examined in these studies included samples collected from various
environments that had been contaminated with dioxins in situ, largely from anthropogenic
sources, as well as test materials prepared by introducing dioxins into test soil in the laboratory
(spiked soil).
In all of the studies, the reference material was a lipid (e.g., corn oil) or organic solvent (e.g.,
acetone) that was spiked with an appropriate level and mixture of congeners to represent the
congener profile in the test soil. Test soil and reference materials were administered to animals
in repeated doses (Bonaccorsi et al. 1984; Budinsky et al. 2008; Wittsiepe et al. 2007) or as a
single (Lucier et al. 1986; McConnell et al. 1984; Shu et al. 1988; Umbreit et al. 1986; Wendling
et al. 1989). Test and reference materials were mixed with food (Bonaccorsi et al. 1984;
Budinsky et al. 2008, Finley et al. 2009) or administered (in most rodent studies) as an aqueous
or lipid vehicle suspension, respectively, by gavage (Bonaccorsi et al. 1984; Lucier et al. 1986;
McConnell et al. 1984; Shu et al. 1988; Umbreit et al. 1986; Wendling et al. 1989).
3.2 Summary of Studies
Studies included in this assessment are described below in alphabetical order and are
summarized in Table 1.
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3.2.1 Bonaccorsi et al (1984) Rabbit Study
Bonaccorsi et al. (1984) estimated RBA of 2,3,7,8-TCDD in soil taken from a contaminated area
at Seveso, Italy. The soil was sieved to 200/300 mesh and analyzed by gas chromatography/
mass spectrometry (GC/MS). The soil had a mean TCDD content of 81±8 ppb. TCDD-free soil
sieved identically was spiked in the laboratory by adding 20 or 40 ppb TCDD in acetone.
Reference test materials consisted of 20 and 40 ppb TCDD in acetone:vegetable oil (v:v, 1:6) and
20 and 40 ppb TCDD in alcohol:water (v:v, 1:1). Soil and reference materials were administered
as a gavage dose with the soil dose suspended in 10 mL water. Groups of male albino rabbits
(2.6±0.3 kg at sacrifice) were administered daily gavage doses for 7 days at the following TCDD
dose levels: 20 ng TCDD/day in acetone:oil (5 rabbits), 20 ng TCDD/day as lab-contaminated
soil (7 rabbits), 40 ng TCDD/day in alcohol or acetone:oil (16 rabbits), 40 ng TCDD/day as lab-
contaminated soil (13 rabbits), 80 ng TCDD/day in alcohol (5 rabbits), 80 ng TCDD/day as lab-
contaminated soil (10 rabbits), 80 ng TCDD/day in Seveso soil (7 rabbits), and 160 ng
TCDD/day in Seveso soil. Animals were killed on the eighth day and livers extracted and
analyzed for TCDD content by GC/MS. TCDD uptake by the liver was similar among the 20 ng
TCDD/day dose groups (TCDD:acetone group and TCDD lab-contaminated soil). At the 40 ng
TCDD/day dose level, liver uptake of TCDD from lab-contaminated soil was 29% less (99% CI
0-53) than the TCDD:solvent control. At the 80 ng TCDD/day dose level, liver uptake of TCDD
from lab-contaminated soil was 44% less (99% CI 19-68) than the TCDD:solvent control,
uptake of TCDD from the Seveso soil sample was 68% less (99% CI 40-95) than the
TCDD:solvent control. Based on reported doses and liver levels in animals that received 80 ng
TCDD/day in Seveso soil in solvent, the RBA for Seveso soil was approximately 32%
(calculated for this report).
3.2.2 Budimky et al (2008) Swine and Rat Studies
Budinsky et al. (2008) estimated RBA of PCDD and PCDF congeners in soil from two sites in
Michigan. The soil samples were sieved (<250 jim). An urban site impacted by past
incineration practices served as one source of soil and reflected a PCDD-dominated TEQ of 264
ppt comprised mainly of 2,3,7,8-TCDD and 1,2,3,7,8-pentachloro-p-dibenzodioxin (PeCD). A
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floodplain site of historic (late 1800s to early 1900s) chloralkali production was the source for
the other soil and reflected a PCDF-dominated TEQ of 651 ppt. The TEQ concentrations were
based on 2005 World Health Organization (WHO) TEQs (Van den Berg et al. 2006).
Information regarding the contributions of specific congeners to the total TEQs is presented in
Appendix B. The reference material was a mixture of the five PCDD/F congeners that
contributed to the five highest mass congener fractions in each soil sample, in corn oil:acetone
(99:1, v/v), and at a target concentration similar to that measured in the corresponding soil
sample.
Swine (Sus scrofa, 6-weeks old, 5 per group) received 10 g soil per day (split into morning and
afternoon doses) for 30 days. Soil samples were placed in moistened feed (1 g soil/10 g feed)
and administered following a 2-hour fast. The reference material (PCDD/F in corn oil:acetone)
was administered in a gelatin capsule placed in moistened feed with two doses each day for 30
days. The daily dosage of PCCD/F was 122 pg TEQ/kg bw/day for the urban soil and 313 pg
TEQ/kg bw/day for the flood plain soil.
Sprague-Dawley rats (females, 6-weeks old, 10 per group) were administered soil as a 5% w/w
soil-feed mixture for a period of 30 days. Food consumption was monitored to estimate daily
dose. The reference material of PCDD/F in corn oil: acetone was administered by gavage for 30
days. The daily dosage of PCCD/F was 577 pg TEQ/kg bw/day for the urban soil and 2100 pg
TEQ/kg bw/day for the flood plain soil.
RBA in swine and rats was estimated from measurements of PCDD/F content of liver and
adipose tissue. Adipose tissue mass as a percent of body weight of rats was estimated from
published allometric relationships. Adipose mass of swine was estimated based on direct
measurements of adipose in three swine. Mean TEQ RBA based on swine assays were 23% for
the urban soil and 27%, for the floodplain soil. The corresponding estimates based on rat assays
were 37% for the urban soil and 66% for the flood plain soil.
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3.2.3 Finley et al (2009) Rat Study
Finley et al. (2009) estimated KB A of PCDD and PCDF congeners in five soil samples collected
from different locations at an operating industrial facility in the U.S. The samples were sieved to
<250 |im particle size and analyzed for PCDD/F content using isotope dilution GC/MS
according to USEPA Method 1613, revision B. PCDFs were the dominant contributors to the
TEQ concentration in the soil samples; TEQ concentrations of the measured PCDD congeners
ranged from 0.014-1.39 ppb (approximately 2.4-3.7% of the total soil TEQ). Information
regarding the contributions of specific congeners to the total TEQs is presented in Appendix B.
Sprague-Dawley rats (female, 15 weeks of age, 5 per group) received a single gavage dose of test
soil (approximately 4 mL/kg bw of aqueous suspension) or reference material (4 mL/kg bw in
corn oil). The congener profiles (i.e., concentration ratios) of the reference materials were based
on the mean fractional contribution of each congener to the total TEQ concentration of the soil
samples used in the study. The concentrations selected for each congener in the reference
formulation was intended to reflect systemic exposures comparable to those of the soil-treated
rats. The rationale for this approach was to estimate RBA at similar internal doses (i.e., liver
levels) for the soil and reference materials, which would result in the same level of hepatic
enzyme induction (i.e., similar metabolic clearance rates). The highest reference dose was
intended to yield approximately 30% of the maximum dose administered to the soil-treated rats
based on the expectation of incomplete absorption of PCDD/Fs from soil. Two lower reference
concentrations (5- and 25-fold lower than the highest concentration) were included to account for
the wide range of total TEQ concentrations in the different soil samples.
Relative bioavailability for selected PCDD/F congeners or for total TEQ were calculated by
dividing the fraction of the administered dose in the liver of soil-treated rats by the mean fraction
of the administered dose in the liver of the corresponding reference rats. TEQ RBA estimates in
the 5 different soil samples ranged from 17 to 50%. Information regarding the contributions of
specific congeners to the TEQ-weighted RBA estimates is presented in Appendix B
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3.2.4 Lucier et al (1986) Rat Study
Lucier et al. (1986) estimated RBA of 2,3,7,8-TCDD in a soil sample collected from a location in
southwest Missouri known as the Minker site, a dumpsite for TCDD-contaminated soil. The soil
was passed through a 60-gauge sieve before assay. Groups of six female Sprague-Dawley rats
(approximate weight of 200 g) were administered single doses of soil by oral gavage (dosing
volume 2 mL in distilled water) at doses ranging from 0.015 jig TCDD/kg bw (0.004 g soil) to
5.5 jig TCDD/kg bw (1.25 g soil). Other groups of rats administered TCDD (in corn oil; dose
volume 0.2 mL/kg bw) by gavage at doses of 1 or 5 ng/kg bw served as reference groups. No
symptoms of acute toxicity were observed. Animals were sacrificed six days following
treatment and livers were analyzed for TCDD content. For rats administered soil at a dose of 5.5
jig TCDD/kg bw, the mean TCDD liver concentration was 20.3±12.9 (standard deviation [SD])
jig/kg liver, compared to a mean TCDD liver concentration of 40.8±6.3 |ig/kg liver for the
reference group dosed at 5.0 jig TCDD/kg bw. At lower doses (1 jig TCDD/kg bw), mean
TCDD liver concentrations were 1.8±0.3 and 7.6±2.5 g/kg liver for the soil-treated, and
reference groups, respectively. Based on these results, RBAs for 1 and 5 jig TCDD/kg bw doses
were estimated in this analysis to be 22 and 45%, respectively (calculated for this report).
3.2.5 McConndl et al. (1984) Guinea Pig Study
McConnell et al. (1984) assessed the bioavailability of TCDD in soil samples from the
Minker/Stout and Times Beach sites in Missouri. Soil TCDD concentrations (soil sifted by 60-
gauge mesh) in the Minker/Stout and Times Beach samples were 880 and 770 ppb, respectively.
Based on these levels, test materials were administered to groups of 6 male Hartley guinea pigs
(2.5-weeks old) by gavage in amounts that delivered TCDD doses of approximately 1, 3, or 10
jig/kg bw (in 5 mL distilled water). Reference animals (6/group) were administered reference
material consisting of pure TCDD in corn oil at 0, 1, or 3 |ig/kg bw. The study authors noted
that a reported LD50 for TCDD in guinea pigs is 2 |ig/kg. An additional control group was
administered 3.6 g of uncontaminated soil (no TCDD, CDFs, or PCBs detected), at a dose equal
to the highest administered dose of contaminated soil. The animals were observed for 30 days
after dosing. At death or terminal sacrifice, livers were extracted and analyzed for TCDD. The 5
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surviving guinea pigs administered 1 jig TCDD/kg bw in corn oil had a mean TCDD liver
content of 1.6±0.2 (standard error [SE]) ppb. TCDD was not detected in livers of guinea pigs
administered 1.3 jig TCDD/kg bw of Times Beach soil or 1.1 jig TCDD/kg bw of Minker/Stout
soil. Higher TCDD doses (i.e., 3-3.8 jig TCDD/kg bw) were lethal to all animals administered
TCDD in corn oil and to some of the animals administered TCDD in contaminated soil. Given
the serious toxi city/lethality observed at the higher doses, estimates of KB A may not be reliable
and are of questionable relevance to healthy animals. Based on liver concentrations of animals
that survived or died before the 30-day observation period concluded, RBA estimates are
approximately 8% for animals administered 3.8 jig TCDD/kg bw in the Times Beach soil, and
11% for animals administered 3.3 jig TCDD/kg bw in the Minker/Stout soil (calculated for this
report). The study of McConnell et al. (1984) includes results of the rat study described in
Lucieretal. (1986).
3.2.6 Shu et al (1988) Rat Study
Shu et al. (1988) estimated bioavailability of 2,3,7,8-TCDD in soil collected from areas of Times
Beach, Missouri that was contaminated in the early to mid-1970s by spraying with a mixture of
TCDD-contaminated oil. Soil samples were sieved through a 40-mesh before use. Measured
TCDD concentrations in 3 soil samples were 1.9, 28.6, and 723 ppb. Uncontaminated soil from
one area of Times Beach, verified for the absence of TCDD, was used to dilute the TCDD-
contaminated soil to provide a range of TCDD doses in the test soil (3.2-1450 ppt). Test
materials were administered as an aqueous suspension (0.25 g soil/mL), as a single gavage dose
(8 mL/kg bw) to groups of 4 male Sprague-Dawley rats (180-250 g body weight). Reference
groups were administered TCDD in corn oil (dose range: 2.0-1180 ng TCDD/kg bw; dose
volume: 4 mL/kg bw). Animals were killed 24 hours post dose and livers were analyzed for
TCDD. A plot of TCDD dose (ng TCDD/kg bw) versus percentage of TCDD concentration in
liver showed that hepatic TCDD levels increased with increasing dose for TCDD administered in
both soil and corn oil and that the slopes for soil-based and corn oil-based hepatic levels were
similar. These data support the validity of using the relative recoveries of TCDD in the liver for
estimating oral bioavailability. Table 1 of Shu et al. (1988) presents values for the absolute
bioavailability for TCDD (mean 42±4%, range: 37-49%). These absolute bioavailability values
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were calculated by adjusting the TCDD dose fraction in liver following dosing with corn oil by
an estimate of the unabsorbed fraction of TCDD when it is administered to rats in corn oil (30%,
Piper et al. 1973). For this report, RBA values were recalculated as the reported absolute
bioavailability times 1.3. The resulting mean RBA was 56±6% (SD, n=6, range: 48-64%).
3.2.7 Umbreit et al (1986) Guinea Pig Study
Umbreit et al. (1986) assessed the bioavailability of 2,3,7,8-TCDD in soil samples collected at a
2,4,5-trichlorophenoxyacetic acid (2,4,5-T) manufacturing site in Newark, New Jersey. Soil
analysis revealed more than 50 PCDD/Fs. TCDD concentration in the soil was approximately
2200 ppb. Experimental groups in the study included PCDD/F-contaminated soil,
decontaminated soil from the same site as a negative control, TCDD in a suspension of corn oil
and acetone (9:1), corn oil as the reference material, and decontaminated soil that was
recontaminated with TCDD 1 hour before use to serve as a positive control. The materials were
administered to groups of guinea pigs (4/sex/group) as single gavage doses and animals were
observed for up to 60 days after dosing. Reported TCDD doses were 3, 6, and 12 jig TCDD/kg
bw for test material and 6 jig TCDD/kg bw for both the recontaminated soil and the corn oil
solvent control. In animals treated with recontaminated soil and TCDD in corn oil, mortality
was >50%, with deaths occurring within 31 days after dosing. No animals died in groups
administered corn oil alone, decontaminated soil, or TCDD-contaminated soil. Liver TCDD
content was determined at terminal sacrifice or at time of death if the animals died before the
observation period ended. A TCDD level of 18 |ig/kg liver was reported for composite liver
samples from 6 of the guinea pigs administered recontaminated soil. A TCDD level of 90 ng/kg
liver was reported for composite liver samples from 4 of the guinea pigs administered
recontaminated soil at a dose of 12 jig TCDD/kg bw. TCDD was not detected in livers from the
five guinea pigs that were analyzed following administration of decontaminated soil.
In a similarly-designed study, TCDD toxicity and liver uptake were assessed for a soil taken
from a salvage site in close proximity to the 2,4,5-T manufacturing site. Residue from stills used
at the manufacturing plant was dumped at this site before recycling of metal from the spent stills.
Groups of guinea pigs (2/sex/group) were administered contaminated soil (reported TCDD dose
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of 320 |ig/kg bw), decontaminated soil, or TCDD in corn oil (6 |ig/kg bw). Three of the animals
administered TCDD in corn oil died within 21 days after dosing. There were no deaths among
the guinea pigs receiving contaminated or decontaminated soil. A TCDD level of 230 ng/kg
liver was reported for composite liver samples from 4 of the guinea pigs administered
contaminated soil.
Liver TCDD levels were not reported for animals that received TCDD in corn oil, precluding
calculation of soil KB A values. However, comparison of the liver TCDD concentrations
following dosing with the site soil with those that were observed following dosing with the
recontaminated soil indicates that soil contaminated in situ had a substantially lower
bioavailability. RBA was less than 1% for the soil from the manufacturing site and
approximately 24% for the soil for the metal yard (calculated for this report).
3.3.8 Wendling et al (1989) Guinea Pig Study
Wendling et al. (1989) assessed the bioavailability of TCDD in soil samples from Times Beach,
Missouri and from a 2,4,5-T manufacturing site in Newark, New Jersey. The Times Beach soil
was contaminated primarily with 2,3,7,8-TCDD (510 ppb) with minor contributions from
heptachloro-p-dibenzodioxin (HpCD) (7.3 ppb) and octochloro-p-dibenzodioxin (OCDD) (12
ppb). The Newark soil contained a mixture of congeners that included 2,3,7,8-TCDD (1400
ppb), PeCD (21 ppb), hexachloro-p-dibenzodioxin (HxCD) (140 ppb), HpCD (3500 ppb), and
OCDD (5400 ppb). Guinea pigs received gavage doses of soil (3-10 jig TCDD/kg bw) or
TCDD in 10% gum acacia. Liver PCDD congener concentrations were determined seven days
after the dose (the time of first death attributed to TCDD). Mean liver concentration in animals
that received 6 jig TCDD/kg bw in gum acacia was 56 ng/g liver. In animals that received 3 or
10 jig TCDD/kg bw in Times Beach soil, mean liver concentrations were 1.9 and 28 ng/g liver,
respectively. Mean liver concentrations in animals that received 5 or 10 jig TCDD/kg in Newark
soil were 94 and 1.5 ng/g liver, respectively. Based on these data, RBA of TCDD in soil
(relative to the gum acacia reference) was approximately 30% for the Times Beach soil and 1.6%
for the Newark soil (calculated for this report).
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The Newark soil contained a mixture of PCDD congeners allowing comparison of liver
concentrations of each congener per unit of congener dose. Based on these data, congener
RBAs, relative to TCDD, were reported as: 1,2,3,7,8-PeCD, 130%; 2,3,6,78-HxCD, 60%;
1,2,3,4,6,7,8-HpCD, 40%; and OCDD 16%.
3.2.9 Wittsiepe et al (200 7) Swine Study
Wittsiepe et al. (2007) assessed RBA of PCDD/Fs in soil (30.6% sand, 36.5% silt, 32.9% clay,
6.8% organic carbon) collected from land that had been treated with sludge from the port of
Hamburg, Germany. Soil particles >1 mm in size were removed by sieving. PCDD/F was
present in soil at 5.3 jig TEQ/kg soil (ppb). The congener pattern showed increasing
concentrations with grade of chlorination and was dominated by PCDF congeners.
The study used two groups of four Goettingen mini-pigs (age 56-78 days at the beginning of the
experiment) that were hand-fed test material in pellets (small amounts of feed, milk powder, and
water) once per day for 28 days. Test material consisted of either 0.5 g PCDD/F-contaminated
soil/kg bw/day (resulting in daily uptake of 2.63 ng TEQ/kg bw/day) or solvent-extracted
PCDD/Fs (hexane-acetone, 50/50) from the same soil that was used for soil test material. The
solvent-extracted material served as the reference material and was administered at a dose of
1.58 mg I-TEQ/kg bw/day. Animals were killed on study day 29 and adipose, liver, muscle,
brain, and blood were extracted and analyzed for PCDD/F content using GC/MS. To assess
whether or not PCDD/Fs in the tissues of the soil-treated and solvent-treated mini-pigs originated
from the feeding of the test materials,, a group of untreated mini-pigs was included; most
PCDD/F congeners were not detectable in tissues from these controls, although a few congeners
were detected in trace amounts. Liver and adipose tissue contained the highest concentrations of
PCDD/Fs in the soil- and solvent-treated mini-pigs. Bioavailability in selected tissues was
calculated as the ratio of the mass of a PCDD/F congener in the tissue to the administered mass
of the same congener from soil or solvent. Relative bioavailability was calculated as the ratio of
the bioavailability in soil to the bioavailability in solvent. Bioavailability and relative
bioavailability data were generated for specific congeners, grouped PCDDs, grouped PCDFs,
and grouped PCDD/Fs for liver, adipose tissue, and all examined tissues combined. RBAs for
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PCDDs were 26.4% (liver), 27.3% (adipose tissue), and 23.2% (total tissues). RBAs for PCDFs
were 35.7% (liver), 23.9% (adipose tissue), and 32.0% (total tissue). RBAs for PCDD/Fs were
31.9% (liver), 25.2% (adipose tissue), and 28.4% (total tissues).
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4.0 DISCUSSION
Data from a subset of the nine reviewed studies were selected for further analyses of KB A for
dioxins in soil. Six studies were selected based the quality and relevance of information
provided in each study (Bonaccorsi et al. 1984; Budinsky et al. 2008; Finley et al. 2009; Lucier
et al. 1986; Shu et al. 1988; Wittsiepe et al. 2007). All selected studies provided RBA estimates
for PCDD/Fs in test materials consisting of soil contaminated with dioxins in situ; studies of
spiked soil materials were not included in this analysis, based on information suggesting that
aging of contaminated soil may decrease the bioavailability of dioxins in soil (Poiger and
Schlatter 1980; Ruby et al. 2002; Umbreit et al. 1986). Studies that administered dose levels of
dioxins that were clearly toxic were not included in this analysis (guinea pig studies by
McConnell et al. 1984; Umbreit et al. 1986; Wendling et al. 1989).
The 6 studies selected for further analysis provided RBA estimates for 13 different test materials
based on assays in the following experimental models:
• Swine: 3 test materials (Budinsky et al. 2008; Wittsiepe et al. 2007);
• Rats: 11 test materials (Budinsky et al. 2008; Finley et al. 2009; Lucier et al. 1986; Shu
etal. 1988); and
• Rabbit: 1 test material (Bonaccorsi et al. 1984).
Only 2 of the 13 test materials were assayed in both swine and rats (Budinsky et al. 2008). Three
studies estimated RBA for multiple dioxin (and furan) congeners with varying levels of
chlorination (Budinsky et al. 2008; Finley et al. 2009; Wittsiepe et al. 2007). The remaining
studies estimated RBAs for 2,3,7,8-TCDD only. All RBA estimates are have been tabulated in
Appendix B.
The following sections analyze the multiple congener RBA estimates for swine and rats (Section
4.1), compare the composite averages estimated from the swine and rat studies (Section 4.2),
analyze the influence of dose on RBA estimates for 2,3,7,8-TCDD (Section 4.3), and discuss the
implications of these findings for site-specific risk assessment (Section 4.4).
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4.1 Analysis for Multiple Congener RBA Estimates
As noted above, three of the six studies selected for further analysis estimated RBA for multiple
dioxin (and furan) congeners with varying levels of chlorination (Budinsky et al. 2008; Finley et
al. 2009; Wittsiepe et al. 2007). These three studies demonstrate a pronounced influence of
chlorine content of each homologue on RBA and distinctly different relationships for RBA
estimates measured in swine and rats (discussion follows).
4.1.1 Multiple Congener RBA Estimates in Swine
RBA estimates for multiple congeners were reported for three test materials based on assays
conducted in swine (Budinsky et al. 2008; Wittsiepe et al. 2007). Table 2 presents summary
statistics for RBA estimates in swine. The regression coefficients (P) for RBA as a function of
congener chlorination for each test material assayed in swine were positive and significant
(p<0.05 with P values ranging from 4.7 to 12.1). RBA estimates for all three test materials
assayed in swine are plotted against chlorine content of each congener (mole chlorine/mole
congener) in Figure 1. Increasing chlorine content was associated with increasing RBA for the
combined data set (P=5.2 RBA per mole Cl/mole congener, R2=0.32, p=0.0013). Mass fractions
of congeners in soils also varied with chlorine content. This resulted in a tendency for higher
administered doses to have higher chlorinated congeners, although the correlation was relatively
weak (r=0.48). However, in a multiple regression analysis in which both chlorine content and
congener dose were included in the regression (discussed in more detail in Section 4.3), dose was
not a significant predictor of RBA.
Two approaches are presented in Table 2 for calculating the composite RBA for the congener
mixture:
Congener mass-weighted mean. In this approach, individual RBA estimates for each
congener are weighted by the mass fraction of each congener in the administered soil
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dose. This also corresponds to the mass fraction in each soil sample. Mass-weighted
estimates were 48.9, 27.0, and 36.6%.
TEQ-weighted mean. In this approach, individual congener KB As are weighted for their
contributions to 2,3,7,8-TCDD TEQ as described by Van den Berg et al. (2006). The
resulting TEQ-weighted estimates are 23.0, 26.6, and 32.9%.
The differences between the mass-weighted and TEQ-weighted composite RBA estimates can be
attributed in part to the significant association between RBA and congener chlorine content. If
the RBAs for all congeners were identical, the mass-weighted and RBA-weighted RBA
estimates would also be identical. The observation that RBA varies with congener chlorine
content has important implications for the estimation of soil dioxin RBA. Soil having different
homologue compositions can be expected to have different RBAs, and the RBA for the total
dioxin mass in a given soil may differ from the RBA for the total TEQ.
Table 2 also presents summary statistics on the unweighted RBA estimates (i.e., mean RBAs of
all congeners in each test material, without weighting the congener-specific RBAs for congener
mass or TEQ mass in the soil). The computed values are not particularly useful to estimate the
composite RBA since they do not account for variations in congener mass or TEQ. However,
they do provide information on the range of values for the individual congeners. The mean RBA
values for the three test materials were 33.8, 30.2, and 28.4%, with the range extending to 55%.
Summary statistics for the combined sample of three test materials assayed in swine are provided
in the bottom rows of Table 2. The mean and SD RBA estimates were 37.5±11.0% for the mass-
weighted average and 27.5±5.1% for the TEQ-weighted average with median values of 36.6%
and 26.6%. Higher values for the mass-weighted estimate reflect the combined effects of a
greater contribution of the more chlorinated homologues in the soil samples and higher RBA
values for these homologues in the swine assays.
These data are not considered adequate or sufficient to establish a nationally-applicable upper
bound estimate of RBA for dioxin in soil. The test materials that have been evaluated in swine
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consist of an urban soil and floodplain soil/sediment in Michigan (Budinsky et al. 2008) and soil
treated with sludge near Hamburg, Germany (Wittsiepe et al. 2007). Two of the test materials
are dominated by PCDFs, with one sample containing less than 1% TCDD-TEQ. These soils do
not represent the range of PCDD/F-contaminated waste nor soil conditions in the U.S.
Nevertheless, were adequate data available from swine assays, reliance on swine RBA estimates,
rather than on rat RBA estimates, would be appealing for reasons. Similarities between the
physiology and anatomy of the swine and human gastrointestinal tracts make swine a preferable
model for predicting RBA in humans than rodent models (USEPA 2007). Swine and rats also
differ in the distribution of absorbed PCCD/Fs. Similar to humans, swine accumulate higher
levels in adipose tissue relative to the liver, whereas, the distribution in rats tends to show the
opposite trend (Budinsky et al. 2008; Thoma et al. 1989, 1990). Using rat liver dioxin burden as
a biomarker may have other more important implications when Connor and Aylward (2006) and
Flaveny et al. (2010) studies on AhR binding are considered.
4.1.2 Multiple Congener RBA Estimates in Rats
An analysis similar to that described above for the swine assays was applied to the multiple
congener RBA estimates for seven test materials assayed in rats in the studies reported by
Budinsky et al. (2008) and Finley et al. (2009). Summary statistics for RBA estimates in rats,
including the regression statistics for the relationship between RBA and congener chlorination,
are presented in Table 3. In contrast to the results obtained from swine assays, increasing
congener chlorine content was significantly associated with lower RBA estimates in rats for each
test material assayed (p<0.05 with P values ranging from -4.2 to 18.3). The combined RBA
estimates for the seven test materials assayed in rats are plotted against chlorine content of each
congener in Figure 2. Although the correlation coefficient for the association was relatively
r\
weak in the combined data (3 = -13.9, R =0.37, p<0.0001), a negative association was
significant (p<0.05), for each of the seven test materials assayed in rats (see Table 3).
Composite average RBA estimates for the seven test materials assayed in rats are also presented
in Table 3. The congener mass-weighted estimates ranged from 10.8-68.3%; the mean and SD
were 28.6±19.3% and the median was 25.1%. The TEQ-weighted estimates ranged from 16.7-
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64.4%; the mean and SD were 40.6±14.8% and median was 37.7%. The lower values for the
mass-weighted estimates reflect the combined effect of higher contribution of the more
chlorinated congeners in the soil samples and lower RBA values for these congeners in the rat
assays. The composite RBA estimates varied approximately 5- to 7-fold. The source of
variability in the composite RBA estimates cannot be explained with currently available data. In
Finley et al. (2009), total organic carbon content of the five soil test materials evaluated was less
than 1% and was stated by the authors to have "varied little" between test materials (data not
reported). The mass distribution of congeners was also similar in the test materials. Other soil
characteristics that may have contributed to the wide range of RBA estimates were not identified
in the study (nor was this the intent of the study).
While the rat studies offer a larger data set for analysis, these data are still considered insufficient
for representing the variability in RBA at U.S. sites having a range of soil characteristics and
congener mixes. Also, the uncertainty regarding the extrapolation of RBA estimates in rodents
to humans is considered too large. A contributing factor to this uncertainty is a lack of
mechanistic understanding of the differences in RBA estimates obtained from swine and rats.
4.2 Comparison of Swine and Rat RBA Estimates
The mean composite RBA estimates for swine (n=3; see Table 2) and rats (n=7, see Table 3) are
not statistically different (mass weighted: p=0.48; TEQ-weighted: p=0.18; unpaired f). Direct
comparison of RBA estimates for identical soil samples assayed in both swine and rats are
available for only two test materials (Budinsky et al. 2008). RBA estimates for these two test
materials are shown in Tables 2 and 3 and are summarized together in Table 4. As shown in
Table 4, there are marked differences in the RBA estimates for swine and rats. The mass-
weighted estimate for test material 1 (TM2) is higher in swine, compared to rats, and the estimate
for test material 2 (TM2) is lower in swine; compared to rats; however, TEQ-weighted estimates
for both materials are lower in swine compared to the estimates in rats (40 and 60%,
respectively). However, the number of comparisons is too small (i.e., two test materials) for
meaningful statistical comparisons.
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Potential contributing factors to the marked differences between the RBA for swine and rats
include physiological differences between swine and rats (e.g., gastrointestinal pH, gastric and
small intestinal transit times) and/or differences between the assay protocols (e.g., dose levels,
multiple dosing vs. single dose; dosing in food vs. gavage dosing). As noted previously,
congener dose was not a significantly influential variable for RBA in swine or rats over the dose
ranges for the three studies. Furthermore, whether the dosing regimen was a single gavage dose
or multiple doses it does not appear to be an important factor based on results reported in
Budinsky et al. (2008). In that study, test material and reference materials were administered in
multiple doses over a period of 30 days in both rats and swine, and RBA was estimated using the
same liver and adipose tissue dioxin burden biomarkers. Even with these similar dosing
protocols, the chlorine-RBA regression coefficients were positive in the swine assays for two test
materials and negative for the rat assays for the identical test materials.
The above results suggest species differences are contributing factors to differences in the RBA
estimates for swine and rats. Although speculative at this point, possible explanations could
include the following:
1. Gastrointestinal transit times. Gastrointestinal transit times could limit the absorption of
materials that are more slowly released from the soil matrix; a limitation that could be
more pronounced in rats that have faster transit times than swine (Rivest et al. 2000;
Tuleu et al. 1999). In all of the studies, reference materials were administered in a corn
oil vehicle and, as noted in Budinsky et al. (2008), differences in absorption of dioxin
congeners from the corn oil vehicle may contribute to the observed differences in RBA
estimates based on the swine and rat assays.
2. Distribution of'absorbed dioxin. Swine and rats also differ in the distribution of absorbed
PCCD/Fs, swine accumulate higher levels in adipose tissue relative to liver, whereas, the
distribution in rats tends to show an opposite trend (Budinsky et al. 2008; Thoma et al.
1989, 1990). A larger fraction of the absorbed dose delivered to the liver in rats could
contribute to a stronger dose-dependence of metabolic clearance in the rat compared to
swine. This has potential implications on the RBA estimates, if liver doses achieved with
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the reference and test materials are not sufficiently similar to ensure similar metabolic
clearances following dosing with each material (see Section 4 for further discussion of
this issue). Using rat liver dioxin burden as a biomarker may have other important
implications if Connor and Aylward (2006) and Flaveny et al. (2010) are considered.
3. AhR affinity and dose-response. Substantial species-specific differences in response to
TCDD are well documented in the literature. The biological response to exposure to
TCDD in a given species is determined by physiological factors, as well as by the
structure and behavior of the AhR at the cellular/molecular level. While a detailed
review of TCDD receptor binding studies is outside the scope of this review mouse AhR
binds TCDD with an approximately 10-fold higher relative affinity than human AhR
(Ramadoss and Perdew 2004). Also interspecies data on the most sensitive and best
understood response to binding of TCDD and related compounds to the AhR are
consistent with higher binding affinity and support the hypothesis that the human AhR is
less functional than the AhR of the more sensitive laboratory animals at a molecular level
as explained comparing enzyme induction to TEQ/kg bw (Connor and Aylward 2006).
Flaveny (2010) elegantly explains the substantial differences between the mouse and
human AhR and structural factors related to lower human AhR affinity for TCDD.
Given the current uncertainty in our understanding of the mechanisms underlying the differences
in observed RBA estimate obtained from swine and rat bioassays, additional studies are needed
to develop a preferred animal model and bioassay protocol for estimating dioxin RBA in soil.
4.3 Influence of Dose on RBA Estimates for 2,3,7,8-TCDD
As noted in the discussion of the multiple congener studies, congener dose did not appear to be a
major influential variable in determining congener RBA over the range of doses examined in
these studies. A larger set of estimates are available for 2,3,7,8-TCDD over a wider range of
dose. Five studies provide RBA estimates for 2,3,7,8-TCDD in six test materials (Bonaccorsi et
al. 1984; Budinsky et al. 2008; Lucier et al. 1986; Shu et al. 1988; Wittsiepe et al. 2007), two of
which were tested at multiple doses of 2,3,7,8-TCDD in rats (Lucier et al. 1986; Shu et al. 1988).
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The individual KB A estimates are plotted against dioxin dose (pg/kg bw/day) in Figure 3. The
estimates based on assays of three test materials in swine appear to exhibit a trend of increasing
RBA with increasing dose; however, no consistent trend is evident from the rat studies (R2=0.12,
p=0.40). The mean value for the data set is 41±19% (SD, n=12) and the range is 2-64%. Shu et
al. (1988) estimated RBAs for 6 doses of 2,3,7,8-TCDD in soil from Times Beach (solid
r\
triangles in Figure 3) and a dose trend is not evident in these data (R =0.36, p=0.21).
4.4 Implications for Risk Assessment
The observation that congeners do not have the same RBA has important implications for the
application of RBA values in dioxin risk assessment. Currently, dioxin risk is estimated based
on assigning TEFs to estimates of average daily intake for chlorinated dibenzodioxin and
dibenzofuran congeners with TEF reflecting the relative toxic potency of each congener, relative
to 2,3,7,8-TCDD (Equation 5).
TEQ = I Ci • TEFi Eq. (5)
where TEQ is the 2,3,7,8-TCDD Toxic Equivalent, d is the concentration of congener /', and
TEFi is the TEF of congener /'. The TEQ value is used in the appropriate equation for average
daily intake (ADITEQ), which is then used in the appropriate risk equation (e.g., Equations 6 and
7):
HQ = Eq. (6)
CR = CSF2i3j7j8_TCDD • ADI7EQ Eq. (7)
where HQ is the hazard quotient, RfD is the reference dose, CR is the cancer risk, and CSF is the
cancer slope factor.
For a dioxin mixture in soil, the RBA adjustment could be applied to the calculation of the TEQ
(Equation 8) or to the calculation of the hazard quotient or cancer risk (Equations 9 and 10):
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TEQ = 2 Ct • T£FE • flB^ Eq. (8)
where RBAt is the soil RBA for congener /'.
HQ = ^TEQ-MATEQ E /^
CR = CSF2i3i7iS_TCDD • AD1TEQ • RBATEQ Eq. (10)
where RBATEQ is the RBA for total TEQ in the soil.
The RBA estimates used in the calculation of TEQ (Equation 8) would be those for the
individual congeners and the sum of the products C; x RBA; would be the congener mass-
weighted RBA for the soil. The RBA estimate used in the calculation of the hazard quotient or
cancer risk (Equations 9 and 10) would be the RBA for total TEQ in the soil. The latter would
be a function of the individual congener RBAs, the congener composition of the soil, and the
congener TEFs.
One limitation of using the RBA for total TEQ is that soil that has similar or identical
characteristics (e.g., total organic carbon and/or particle size), but different congener
composition could have different RBAs for total TEQ. On the other hand, using RBA values for
specific congeners would be expected to be relatively constant for soil having identical
characteristics. On this basis, it would appear that the preferred approach to developing site-
specific soil cleanup levels would be to determine RBA values for specific congeners and apply
them in risk assessments in a computation similar to Equation 8.
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5.0 SUMMARY AND CONCLUSIONS
5.1 Summary of Findings
Collectively, analyses of published KB A estimates for PCDD/F in soil supports the following
conclusions:
1. RBA for PCDD/F mixtures in soils assayed in swine and rats is less than 100%.
2. RBA varies with congener chlorination. The direction of the relationship (i.e., positive or
negative slope) is not the same when estimated based on data from swine or rat assays.
Data from swine assays indicates an increase in RBA with increasing chlorine content
(Budinsky et al. 2008; Wittsiepe et al. 2007), whereas, data from rat assays indicates a
decrease in RBA with increasing chlorination (Budinsky et al. 2008; Finley et al. 2009).
These differences suggest substantially different RBA estimates may be obtained
depending on the animal model used.
The National Academy of Sciences (NAS 2006), the World Health Organization (Van
den Berg et al. 2006), other international committees and organizations, the U.S.
Environmental Protection Agency (USEPA 2003), and other state agencies (e.g.,
WASDE 2007) have recognized that soil will influence the bioavailability of mixtures of
dioxins/furans and have concluded that higher chlorinated congeners tend to be less
bioavailable than the more chlorinated congeners. However, observations and analyses
reported here suggest that the effect of chlorination on the RBA of dioxins in soil may be
different for different animal models, as shown in the recently reported swine assays.
3. The dependence of RBAs on congener chlorination suggests soil RBA will depend on the
congener composition of the soil (as well as the bioassay used to estimate RBA).
Congeners with different levels of chlorination result in different composite RBA
averages for soil when calculated based on total congener mass or 2,3,7,8-TCDD TEQ.
For example, based on the swine RBA assays, octochloro-p-dibenzodioxins (OCDD; 8
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chlorines substituted on 8 available positions on the carbons of the benzene rings on
either side of the central diheterabenzene, or "CIS") and octochlorodibenzofurans
(OCDFs, CIS) will have a higher RBA than lower chlorine content congeners. Thus, for
soil highly enriched with OCDDs and OCDFs (i.e., higher RBA and lower TEF), the
RBA based on total congener mass will be higher than the RBA based on total TEQ. If,
on the other hand, the soil RBA is based on rat RBA assays, high enrichment of OCDDs
and OCDFs would result in higher TEQ RBAs compared to RBAs for total congener
mass.
4. The influence of abiotic constituents, compound aging, and other associated soil factors
on soil RBA has not been evaluated systematically. Bioavailability appears to decrease
with aging based on comparisons of laboratory spiked soil and soil contaminated in situ
(Poiger and Schlatter 1980; Umbreit et al. 1986) and is lower when administered as a
mixture of activated carbon compared to an aqueous suspension (Poiger and Schlatter
1980). The latter observation suggests that organic carbon content influences dioxin
bioavailability from soil.
5. Although RBA for dioxins in soils evaluated in these studies is less than 100%,
estimating a representative range or upper bound value for RBA from these data is
problematic, however, because of the limited number of estimates, the effect of congener
chlorination on RBA, and differences in the estimates based on swine and rat assays.
In the swine studies, the total congener mass RBAs average 38% and range up to 50%;
the total TEQ RBAs average 28% and range up to 33%. A statistically robust description
of the distribution of the RBA values cannot be estimated from these swine studies, as
they consist only of three test materials. Nevertheless, were adequate data available from
swine assays, reliance on swine RBA estimates, as opposed to rat RBA estimates, would
be appealing for several reasons. Similarities between the physiology and anatomy of the
swine and human gastrointestinal tracts make swine a preferable model for predicting
RBA in humans than rodent models (USEPA 2007). Swine and rats also differ in the
distribution of absorbed PCCD/Fs. Similar to humans, swine accumulate higher levels in
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adipose tissue relative to the liver, whereas the distribution in rats tends to show the
opposite trend (Budinsky et al. 2008; Thoma et al. 1989, 1990). Moreover, using rat liver
dioxin burden as a biomarker may have other implications related to species differences
in binding to the AhR and induction of CYP450, the major route of metabolic clearance
of PCDD/Fs (Budinsky et al. 2008; Connor and Aylward 2006; Finley et al. 2009;
Flavenyetal. 2010).
In the rat studies, the total congener mass RBAs average 29% and range up to 68%; the
total TEQ RBAs average 41% and range up to 64%. While the rat studies offer a larger
data set for analysis, these data are still considered insufficient for representing the
variability in RBA at U.S. sites having a range of soil characteristics and congener mixes.
Also, the uncertainty regarding the extrapolation of RBA estimates in rodents to humans
is considered too large. A contributing factor to this uncertainty is a lack of mechanistic
understanding of the differences in RBA estimates obtained from swine and rats.
A similar analysis of RBA data was reported by the State of Washington Department of
Ecology (WASDE 2007). The date of this analysis preceded the publication of the Finley
et al. (2009) rat study and the Budinsky et al. (2008) swine and rat studies. It should be
noted that all other studies reported in WASDE (2007) are also reviewed in this report,
although, not all studies were included in the analyses presented in this report. In
particular, studies conducted in guinea pigs were not included in the analyses for this
report because these studies administered TCDD doses at or above the LDso for guinea
pigs. In addition, analyses in the current report were restricted to studies that evaluated
soil contaminated with PCDD/F in situ (not soils spiked in the laboratory).
Based on analysis of the available at the time congener-specific analyses, WASDE
(2007) concluded that the weighted gastrointestional absorption for most mixtures will
fall within the range of 0.4 to 0.6, with the most likely value being 0.5. WASDE (2007)
selected a value of 40% for a default RBA to be used in risk assessments, calculated by
dividing 30% absolute bioavailability (value used to characterize absorption of soil-
bound dioxins and furans) by 80% (value used to characterize absolute bioavailability of
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dioxin/furan in the toxicological studies used to calculate the cancer slope factor). The
basis for the estimate of 30% for the absolute bioavailability is not clearly articulated. As
previously discussed (see Section 2.2), none of the studies cited in this analysis or in
WASDE (2007) provided data amenable to estimating absolute bioavailability.
Although the Wittsiepe et al. (2007) swine study is cited in WASDE (2007), it is
discussed only in the context of reported values of absolute bioavailability. As noted
previously (see Section 2.2), the method used to estimate absolute bioavailability in the
Wittsiepe et al. (2007) study (and in all studies considered in this analysis) would have
underestimated the absorption fraction by an amount related to the elimination fraction,
which was not reported. For this reason, no attempt was made to estimate absolute
bioavailability from the Wittsiepe et al. (2007) study or any other studies for the current
analysis.
5.2 Uncertainties in RBA Estimates
Several important uncertainties would apply to any risk assessment applications of the RBA
estimates provided in this report.
1. The RBA estimates considered in this analysis do not represent a statistical sample of soil
in any particular geographic region that is representative of all soil in the U.S. and may or
may not adequately represent the variability expected over a wider range of soil types and
compositions. As a result, site-specific RBA assessments may be preferable to
application of a range and upper bound value based on this limited data set.
2. Significant differences are evident between RBA estimates for test materials assayed in
swine and rats. This includes large differences in the average RBA values for the same
test material assayed in swine and rats (Budinsky et al. 2008), as well as regression
coefficients for the effect of congener chlorine content on RBA that are in opposite
directions. Explanations for these differences are not apparent from the data and are
probably due to species differences and less likely from differences in assay protocols.
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No studies that compared RBA in humans to RBA estimated from animal models were
retrieved in the literature search.
3. Estimates of RBA based on both the swine and rat assays show significant association
between chlorine content of dioxin congeners and RBA. Because of this correlation,
average RBA for a given soil, based on either congener mass or total TEQ, can be
expected to vary with the congener composition of the soil. Given this source of
variability, the preferred approach for risk assessment would be to derive congener-
specific RBA estimates. The currently available data provide RBA estimates for chlorine
content classes of congeners. Estimates have large coefficients of variation that introduce
relatively large uncertainty into the estimates for most chlorination classes.
4. RBA estimates made in this analysis assume that elimination kinetics of PCDD/F
absorbed from soil are the same or very similar to PCDD/F absorbed from the reference
vehicle (e.g., corn oil). If the elimination kinetics are not the same, RBAs calculated in
the cited reports, and in this analysis, will not reflect the actual differences in the
absorption fractions for the soil and reference materials. For example, if the rate of
elimination of the PCDD/F absorbed from the reference material was greater than from
the soil material, RBA estimates would be biased low (i.e., the ID/ED ratios for reference
and test material will yield an underestimate of the true RBA).
This problem becomes important if the absorbed doses from the reference and soil
materials are sufficiently different to result in different levels of enzyme induction and,
thereby, different elimination kinetics. This was the outcome of rat studies, but not in the
swine studies, reported in Budinsky et al. (2008); enzyme induction (as measured by liver
P4501A activity) was higher in rats that received the dose in test material compared to
soil. If these differences resulted in faster elimination of absorbed PCDD/F in animals
that received the reference material, then the RBAs calculated for these test materials
may have been underestimated in the rats. The magnitude due to the underestimation
cannot be estimated from data reported in Budinsky et al. (2008). In the Finley et al.
(2009) rat study, doses in soil and reference materials were adjusted with the intention of
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yielding approximately the same liver concentrations of PCDD/F. For two of the test
materials (TM 2 and TM 3), induction was significantly greater following the test
material dose compared to the reference dose. If these differences resulted in faster
elimination of absorbed PCDD/F in animals that received the test material, then the
KB As calculated for these test materials may have been overestimated. Here again, the
magnitude of the overestimate cannot be estimated from the data reported in Finley et al.
(2009).
5. All KB A estimates considered in this analysis were made relative to a lipid or organic
solvent vehicle as the reference material (e.g., corn oil). The direct relevance of this type
of vehicle to the exposures that formed the bases for the cancer slope factor and/or RfD
need to be considered in evaluating their applicability to cancer and non-cancer risk
assessment.
Given the above uncertainties, currently available data do not support the general application of
RBA estimates from this report to risk assessment. However, available data suggest that RBA
values less than 100% can be expected at sites. On this basis, EPA encourages the collection of
site-specific data for the purpose of informing decision making at specific sites.
5.3 Conclusions
Collectively, these results support the conclusion that the RBA for dioxin in the soils evaluated
in these studies is less than, and likely to be substantially less than 100%. However, estimating a
representative range or upper bound value for RBA from these data is problematic, because of
the limited number of estimates, the effect of congener chlorination on RBA, and differences in
the estimates based on swine and rat assays. Thus, while substantial progress has been made in
the science of estimating RBA of dioxins in soils, EPA considers the currently available data to
be inadequate for estimating a nationally applicable value for RBA for use in developing soil
cleanup levels for dioxin. Furthermore, EPA considers currently the available data to be
insufficient for determining a preferred animal model, or bioassay protocol for predicting soil
RBA in humans. Thus, until such time that a nationally-applicable value for dioxin RBA can be
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established, collection of site-specific data is recommended to inform site-specific cleanup
decisions.
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6.0 REFERENCES
ATSDR (Agency for Toxic Substances and Disease Registry). 1998. Toxicological Profile for
Chlorinated Dibenzo-p-Dioxins. Centers for Disease Control and Prevention, Agency for Toxic
Substances and Disease Registry. Atlanta, GA. Available online from:
http://www.atsdr.cdc.gov/ToxProfiles/tp.asp?id=366&tid=63.
Bonaccorsi A, diDomenico A, Fanelli R, Merlin F, Motta R, Vanzati R, Zapponi GA. 1984. The
influence of soil particle adsorption on 2,3,7,8-tetrachlorodibenzo-p-dioxin biological uptake in
the rabbit. Disease, metabolism, and reproduction in the toxic response to drugs and other
chemicals. Arch Toxicol Suppl 7:431-434.
Budinsky RA, Rowlands JC, Casteel S, Pent G, Cushing CA, Newsted J, Giesy JP, Ruby MV,
Aylward LL. 2008. A pilot study of oral bioavailability of dioxins and furans from contaminated
soils: Impact of differential hepatic enzyme activity and species differences. Chemosphere
70(10): 1774-1786.
Connor KT, Aylward LL 2006. Human response to dioxin: aryl hydrocarbon receptor (AhR)
molecular structure, function, and dose-response data for enzyme induction indicate an impaired
human AhR. J Toxicol Environ Health B Crit Rev. 9(2): 147-171.
Finley B, Fehling K, Warmerdam J, Morinello EJ. 2009. Oral bioavailability of polychlorinated
dibenzo-p-dioxins/dibenzofurans in industrial soils. Hum Ecol Risk Assess 15:1146-1167.
Flaveny CA, Murray IA, Perdrew GH. 2010. Differential gene regulation by the human and
mouse aryl hydrocarbon receptor. Toxicol Sci 114(2):217-325.
Lucier GW, Rumbaugh RC, McCoy Z, Hass R, Harvan D, Albro P. 1986. Ingestion of soil
contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters hepatic enzyme activities
in rats. Fundam Appl Toxicol 6:364-371
McConnell EE, Lucier GW, Rumbaugh RC, Albro PW, Harvan DJ, Hass JR, Harris MW. 1984.
Dioxin in soil: Bioavailability after ingestion by rats and guinea pigs. Science 223:1077-1079.
NAS (National Academy of Science). 2006. Health Risks from Dioxin and Related Compounds:
Evaluation of the EPA Reassessment. National Academy Press.
Piper WN, Rose JQ, Gehring PJ. 1973. Excretion and tissue distribution of 2,3,7,8-
tetrachlorodibenzo-p-dioxin in the rat. Environ Health Perspect 5:241-244.
Poiger H, Schlatter C. 1980. Influence of solvents and adsorbents on dermal and intestinal
absorption of TCDD. Food Cosmet Toxicol 18:477-481.
Page 46 of 52
-------
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Ramadoss P, Perdew GH 2004. Use of 2-azido-3-[125I]iodo-7,8-dibromodibenzo-p-dioxin as a
probe to determine the relative ligand affinity of human versus mouse aryl hydrocarbon receptor
in cultured cells. Mol Pharmacol 66(1): 129-136.
Rivest J, Bernier JF, Pomar C. 2000. A dynamic model of protein digestion in the small intestine
of pigs. J Anim Sci 78:328-340.
Ruby MV, Fehling KA, Paustenbach DJ, Landenberger BD, Holsapple MP. 2002. Oral
bioaccessibility of dioxins/furans at low concentrations (50-350 ppt toxicity equivalent) in soil.
Environ Sci Technol 36(22):4905-4911.
Shu H, Paustenbach D, Murray FJ, Marple L, Brunck B, Rossi DD, Teitelbaum P. 1988.
Bioavailability of soil-bound TCDD: Oral bioavailability in the rat. Fund Appl Toxicol 10:648-
654.
Thoma H, Mucke W, Kretschmer E. 1989. Concentrations of PCDD and PCDF in human fat and
liver samples. Chemosphere 18:491-498.
Thoma H, Mucke W, Kuert G. 1990. Concentrations of polychlorinated dibenzo-p-dioxin and
dibenzofuran in human tissue and human liver. Chemosphere 20:433-442.
Tuleu C, Andrieux C, Boy P, Chaumeil JC. 1999. Gastrointestinal transit of pellets in rats: Effect
of size and density. Int JPharm 180(1):123-131.
Umbreit TH, Hesse EJ, Gallo MA. 1986. Bioavailability of dioxin in soil from a 2,4,5-T
manufacturing site. Science 232:497-499.
USEPA (U.S. Environmental Protection Agency). 1989. Risk Assessment Guidance for
Superfund: Volume III - Part A, Process for Conducting Probabilistic Risk Assessment. Office of
Emergency and Remedial Response, U.S. Environmental Protection Agency, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 2003. Exposure and Human Health
Reassessment of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds.
National Center for Environmental Assessment
Research and Development, U.S. Environmental Protection Agency, Washington, DC.
December 2003, NAS Review Draft (available at www.epa.gov/ncea/dioxin).
USEPA (U.S. Environmental Protection Agency). 2007. Estimation of Relative Bioavailability
of Lead in Soil And Soil-Like Materials Using In Vivo and In Vitro Methods. Office of Solid
Waste and Emergency Response, U.S. Environmental Protection Agency, Washington, DC
20460. OSWER 9285.7-77.
Van den Berg M, Birnbaum LS, Denison M, De Vito M, Farland W, Feeley M, Fiedler H,
Hakansson H, Hanberg A, Haws L, Rose M, Safe S, Schrenk D, Tohyama C, Tritscher A,
Tuomisto J, Tysklind M, Walker N, Peterson RE. 2006. The 2005 World Health Organization re-
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evaluation of human and mammalian toxic equivalency factors for dioxins and dioxin-like
compounds. Toxicol Sci 93(2):223-241.
WASDE (Washington State, Department of Ecology). 2007. Relative Bioavailability Estimates
for Dioxins/Furans in Soil. Discussion paper prepared for USEPA Science Advisory Board.
March 2007.
Wendling T, Hileman F, Orth R, Umbreit T, Hesse, Gallo M. 1989. An analytical assessment of
the bioavailability of dioxin contaminated soils to animals. Chemosphere 18:925-932.
Wittsiepe J, Erlenkamper B, Welge P, Hack A, Wilhelm M. 2007. Bioavailability of PCDD/F
from contaminated soil in young Goettingen mini-pigs. Chemosphere 67(9):S355-S36.
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Table 1. Summary of RBA Studies of Dioxins in Soil
Reference
Bonaccorsi et al.
1984
Test Material
Source: Seveso, Italy soil
(200-400 mesh)
TCDD Concentration: 81 ng/g
(ppb)
Species/Number
Rabbit (Albino, male, 2.6±0.3
kg), 5-16/group
Methods
ID Metric: liver TCDD
concentration
TMDose: 0.02 to 0.08 ug
TCDD/day; 7 days
RBA
32%
Budinsky et al. 2008
Budinsky et al. 2008
Finley et al. 2009
Source: TM1: urban soil,
Michigan
(sieved to <250 um)
PCDD/F: 264 pg TEQ/g (ppt)
Source: TM1: floodplain soil,
Michigan
(sieved to <250 um)
PCDD/F: 65Ipg TEQ/g
Source: urban soil, Michigan
(sieved to <250 um)
PCDD/F: 264 pg TEQ/g (ppt)
Source: floodplain soil,
Michigan
(sieved to <250 um)
PCDD/F: 651 pg TEQ/g (ppt)
Source: Operating U.S.
industrial facility
(sieved to <250 um)
PCDD/F Concentrations:
TM1: 15.0 ng TEQ/g soil
TM2: 45.0 ng TEQ/g soil
TM3: 36.8 ng TEQ/g soil
TM4:2.8ngTEQ/gsoil
TM5: 0.53 ng TEQ/g soil
(ppb)
Swine (Sus scrofa, sex and
weight not given), 5/group
Rat (Sprague-Dawley, female,
250 g), 10/group
Rat (Sprague-Dawley, female,
251-321g),6/group
TM Dosing: aqueous suspension,
oral gavage, single dose
RM Dosing: oral gavage in 50%
ethanol, single dose
ID Metric: liver plus adipose
PCDD/F content
TMDose: 122, 313 pgTEQ/kg-
bw/day
TM Dosing: 5 g soil placed in
moistened feed, twice/day, 30 days
RM Dosing: corn oil/acetone (99:1
v:v) in gelatin capsule, placed in
moistened feed, twice/day, 30 days
ID Metric: liver plus adipose
PCDD/F content
TMDose: 577, 2100 pgTEQ/kg
bw/day
TM Dosing: 5% w/w soil-feed
mixture, 30 days
RM Dosing: corn oil/acetone (99:1,
v:v), oral gavage, 30 days
ID Metric: liver PCDD/F content
TM Dosing: aqueous suspension,
oral gavage, single dose
TMDose:
TM1: 30,000 pg TEQ/kg bw/day
TM2: 90,200 pg TEQ/kg bw/day
TM3: 590 pg TEQ/kg bw/day
TM4: 560 pg TEQ/kg bw/day
TM5: 290 pg TEQ/kg bw/day
RM Dosing: corn oil, oral gavage,
single dose
23% (urban)
27% (flood plain)
(TEQ-weighted)
37% (urban)
66% (flood plain)
(TEQ-weighted)
TM1: 16.7%
TM2: 48.4%
TM3: 37.7%
TM4: 46.5%
TM5: 33.3%
(TEQ Weighted)
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Table 1. Summary of RBA Studies of Dioxins in Soil
Reference
Lucieretal. 1986
Test Material
Source: Minker/Stout site,
Missouri
(sieved 60 gauge)
TCDD: 880 ng/g (ppb)
Species/Number
Rat (Sprague-Dawley,
female), 6/group
Methods
ID Metric: liver TCDD
concentration
TMDose: 1.1, 5.5 ugTCDD/kg-bw
TM Dosing: aqueous suspension,
RBA
22% (1. lug/kg)
45% (5.5 mg/kg)
McConnell et al.
1984
Shuetal. 1988
Source: Times Beach site,
Missouri
(sieved 60 gauge)
TCDD: 770 ng/g (ppb)
Source: Minker/Stout, Missouri
(sieved 60 gauge)
TCDD: 880 ng/g (ppb)
Source: Times Beach soil,
Missouri
(sieved through 40 mesh
screen)
TCDD: 1.9 to 723 ng/g (ppb)
Guinea pig (Hartley, male, 2.5
weeks old), 6/group
Rat (Sprague-Dawley derived,
180 to 250 g), 4/group
Umbreitetal. 1986
Source: Manufacturing plant in Guinea pig (males and
Newark, NJ females; strain, weight and
TCDD: -2,300 ng/g (ppb) age not given, 8/group)
Source: Salvage yard
contaminated with chemical
stills, Newark NJ
TCDD: NR
Wendling et al. 1989 Source: Times Beach. Michigan Guinea pig (200 g), 2/group
TCDD: 510 ng/g (ppb)
Source: Newark, NJ
TCDD: 1,400 ng/g (ppb)
oral gavage, single dose
RM Dosing: corn oil, oral gavage,
single dose
ID Metric: liver TCDD
concentration
TM Dosing: aqueous suspension,
oral gavage, single dose
TMDose: 1-10 ug TCDD/kg
bw/day
RM Dosing: corn oil, oral gavage,
single dose
ID Metric: liver TCDD
concentration
TM Dosing: aqueous suspension,
oral gavage, single dose
TMDose: 3.2, 7.0, 40, 37, 175,1450
ng TCDD/kg
RM Dosing: corn oil, oral gavage,
single dose
ID Metric: liver TCDD
concentration
TMDose: 3, 6, 12 ug TCDD/kg
TM Dosing: aqueous suspension,
oral gavage, single dose
RM Dosing: corn oil/acetone (9:1,
v:v), oral gavage, single dose
ID Metric: liver TCDD
concentration
TM Dosing: 10% gum acacia, oral
gavage, single dose
TMDose: 3-10 ug TCDD/kg
RM Dosing: 10% gum acacia, oral
gavage, single dose
8%
(Times Beach, 3.8 ug/kg,
20% lethality)
11%
(Minker Stout, 3.3 ug/kg,
33% lethality)
44%(3.2ng/kg)
49% (7 ng/kg)
38% (40 ng/kg)
43% (37 ng/kg)
45% (175 ng/kg)
37% (1450 ng/kg)
(manufacturing site, 12
ug/kg, relative to spiked soil)
24%
(salvage yard, 0.32 ug/kg,
relative to spiked soil)
7%, 30%
(Times Beach, 3 or 10 ug/kg)
2.0, 1.6%
(Newark, 5 or 10 ug/kg)
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Table 1. Summary of RBA Studies of Dioxins in Soil
Reference
Test Material
Species/Number
Methods
RBA
Wittsiepe et al. 2007
Source: Surface soil near
Hamburg, Germany
PCDD/F: 5.3 ng TEQ/g (ppb)
Swine (Goettingen mini-pig,
males and females, 6975 g),
4/group
ID Metric: PCDD/F content of
tissues (adipose, blood, brain, liver,
muscle)
TM Dosing: 0.5 g soil/kg bw/day
placed in moistened feed
TMDose: 2.3 ng TEQ/kg bw/day,
28 days
PJV1 Dosing: hexane/acetone (1:1,
v:v), placed in moistened feed, 28
days
28.4±9.9 (SD)
(total congener)
ID, internal dose; NR, not reported; PCDD/F, polychlorinated dibenzo-p-dioxin/dibenzo furan; ppb, parts per billion; pg, pictogram; ppt, parts per trillion; RM, reference material;
SD, standard deviation; TCDD, tetrachloro-p-dibenzodioxin; TEQ, toxic equivalent; TM, test material; \im, micron
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Table 2. Summary Statistics for Multiple Congener RBA Estimates in Swine
Individual Study Statistics
Congener mass-weighted mean
TEQ-weighted mean
Unweighted congener mean
Unweighted congener SD
Unweighted congener MIN
Unweighted congener MAX
Chlorine-RB A regression coefficient
Chlorine-RB A regression R2
TM Summary Statistics
Congener mass-weighted3
TEQ-weightedb
Unweighted congener
BU08 TM1
48.9
23.0
33.8
16.5
18.0
55.0
12.2
0.94
Mean
37.5
27.5
30.8
BU08 TM2
27.0
26.6
30.2
6.1
22.0
37.0
7.1
0.95
SD
11.0
5.1
2.7
WI07
36.6
32.9
28.4
9.9
2.0
42.2
4.7
0.31
MIN MED
27.0 36.6
23.0 26.6
28.4 30.2
MAX
48.9
32.9
33.8
Based on data for urban soil (TM1) and flood plan soil (TM2) reported in Budinsky et al. 2008 (BU08); and data for one soil test
material reported in Wittsiepe et al. 2007 (WI07).
a Weighted average, where weights are congener dose (pg/kg bw/day).
b Weighted average, where weights are TEQ dose (pg/kg bw/day), based on Van den Berg et al. (2006) TEF assignments.
MAX, maximum; MED, median; MIN, minimum; RBA, relative bioavailability; SD, standard deviation; TEQ, toxic equivalent;
TM, test material
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Table 3. Summary Statistics for Multiple Congener RBA Estimates in Rats
Individual Study Statistics
Congener mass-weighted mean
TEQ-weighted mean
Unweighted congener mean
Unweighted congener SD
Unweighted congener MIN
Unweighted congener MAX
Chlorine-RB A regression coefficient
Chlorine-RB A regression R2
TM Summary Statistics
Congener mass-weighted15
TEQ-weightedc
Unweighted congener
BU08
TM1
34.9
37.2
39.2
5.2
34.0
47.0
-4.2
0.40
MEAN
28.6
40.6
42.2
BU08
TM2
68.3
64.4a
62.4
15.0
52.0
89.0
-17.5
0.55
SD
19.3
14.8
14.3
FO09
TM1
10.8
16.7
17.3
7.3
5.0
27.0
-18.3
0.68
MIN
10.8
16.7
17.3
FI09
TM2
25.1
48.4
50.5
25.7
16.0
100
-13.5
0.42
MED
25.1
37.7
39.3
FI09
TM3
17.0
37.7
39.3
22.1
13.0
79.0
-15.8
0.82
MAX
68.3
64.4
62.4
FI09
TM4
28.4
46.5
50.9
22.9
19.0
82.0
-4.2
0.40
FI09
TM5
15.7
33.3
35.8
18.1
13.0
61.0
-17.5
0.55
Based on data for urban soil (TM1) and flood plan soil (TM2) reported in Budinsky et al. 2008 (BU08); and data for sample 1-5
(TM1-TM5) reported in Finley et al. 2009 (FI09).
a Budinsky et al. (2008, see Table 6) reported 66%; the reason for the difference is not apparent.
b Weighted average, where weights are congener dose (pg/kg bw/day).
0 Weighted average, where weights are TEQ dose (pg/kg bw/day), based on Van den Berg et al. (2006) TEF assignments.
MAX, maximum; MED, median; MIN, minimum; RBA, relative bioavailability; SD, standard deviation; TEF, toxic equivalence
factor; TEQ, toxic equivalent; TM, test material
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Table 4. Comparison of RBA Estimates for Swine and Rats in Identical Test Materials
Swine RBA (%) Rat RBA (%) Swine/Rat Ratio
TM1 (mass-weighted) 48.9 34.9 1.4
TM1 (TEQ-weighted) 23.0 37.2 0.6
TM2 (mass-weighted) 27.0 68.3 0.4
TM2 (TEQ-weighted) 26.6 64.4 O4
Based on data from Budinsky et al. (2008).
RBA, relative bioavailability; TEQ, toxic equivalent; TM, test material
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80
60
20
AWI07SW
BU08SW
y = 5.2211x-0.3211
R2 = 0.3438
A
4
56
Chlorine#
Figure 1. Relationship between congener chlorine content (mole chlorine/mole congener)
and RBA based on swine assays of three test materials (Budinsky et al. 2008, BU08;
Wittsiepe et al. 2007, WI07). The regression equation is for the combined data from both
studies; regression coefficients for the individual studies are provided in Table 1.
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CD
DC
100
80
60
40 -\
20
o -4
5 6
Chlorine #
y = -13.07x+119.29
R2 = 0.354
OFI09TM1
AFI09TM2
XFI09TM3
XFI09TM4
OFI09TM5
DBU08TM1
+ BU08TM2
Figure 2. Relationship between congener chlorine content (mole chlorine/mole congener)
and RBA based on rat assays of seven test materials (Budinsky et al. 2008, BU08; Finley et
al. 2009, FI09). The regression equation is for the combined data from both studies; regression
coefficients for the individual studies are provided in Table 2.
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80
60
S?
CQ
cc.
OTCDD PIG
ATCDD RAT SH88
ATCDD RAT LU86
DTCDD RAB
D
0 T-
l.E+00
l.E+01 l.E+02
l.E+03 l.E+04
Dose (pg/kg-day)
l.E+05 l.E+06
l.E+07
Figure 3. Relationship between 2,3,7,8-TCDD dose (pg/kg bw/day) and RBA based on
swine, rat, and rabbit assays of six test materials (Bonaccorsi et al. 1984; Budinsky et al.
2008; Lucier et al. 1986; Shu et al. 1988; Wittsiepe et al. 2007).
Page 57 of 52
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Appendix A - Literature Search Product:
Bioavailability of Dioxins in Soil
-------
LITERATURE SEARCH PRODUCT:
BIO AVAILABILITY OF DIOXINS IN SOIL
Prepared for:
Bioavailability Subcommittee of the Technical Review Workgroup
Office of Solid Waste and Emergency Response
U.S. Environmental Protection Agency
Washington, DC 20408
Prepared by:
Julie Klotzbach
SRC, Inc.
Chemical, Biological, and Environmental Center
6502 Round Pond Road
North Syracuse, NY 13212
January 5, 2010
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DRAFT 7-Do Not Cite, Quote, or Distribute - DRAFT 7
INTRODUCTION
Search Strategy
The following strategy was used to identify literature pertinent to the topic of bioavailability of
dioxin in soil:
1. Literature published before 1998 was identified from the text and bibliography of the
current (1998) ATSDR Toxicological Profile for Chlorinated Dibenzo-p-Dioxins.
2. Literature published subsequent to 1998 was identified based on results of a dioxin
literature evaluation conducted in 2008 (for the period 1998-2008).
3. Literature published subsequent to 2008 was identified from a de novo bibliographic
search (e.g., MEDLINE/TOXLINE) conducted for the period 2008-present. The search
strategy focused on relevant literature (e.g., absorption, bioavailability).
Literature Search Product Organization
The literature search product is organized by topic, with subsections organized by species where
appropriate, as follows:
1.0 Bioavailability and Pharmacokinetics Studies in Humans
1.1 Soil
1.2 Other Media
2.0 Bioavailability and Pharmacokinetics Studies in Animals
2.1 Soil (organized by species)
2.2 Other Media (organized by species)
3.0 Toxicity Studies of Dioxin in Soil in Animals (organized by species)
4.0 In Vitro Bioaccessibility
5.0 PBPK Modeling
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6.0 Risk Assessments
7.0 Reviews
Considerations
General considerations in identifying pertinent studies:
1. Studies and information that may yield useful quantitative information about absolute or
relative bioavailability (ABA or RBA, respectively) of dioxins may include (in order of
decreasing value and certainty regarding RBA estimates):
a. Studies in which bioavailability (e.g., dioxin concentrations in serum or tissue lipid)
of dioxins were directly compared in animals exposed to dioxins in food or soil (e.g.,
analogous to swine RBA studies for lead or arsenic).
b. Comparisons of results of separate studies in which bioavailability of dioxins were
measured in animals exposed to dioxins in food or soil. These studies could include
toxicity studies in which serum and/or tissue samples were assayed for dioxin levels
using comparable methods.
c. Pharmacokinetic modeling studies in which bioavailability of dioxins in food and/or
soil may have been estimated based on fitting bioavailability parameter values to
observations (e.g., dioxin concentrations in serum or tissue lipid).
d. Studies in which toxic potency (e.g., EDso) were compared in animals administered
dioxins in food or soil.
2. Currently, dioxin risk is estimated based on assigning TEF to estimates of average daily
intake for dioxin congeners, where the TEF values reflect relative toxic potency of each
congener, relative to 2,4,7,8-TCDD (Equation 1).
01/05/10 PageA-iv SRC/Klotzbach
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TEQ = I Cr TEFi Eq. (1)
where TEQ is the 2,4,7,8-TCDD Toxicity Equivalent, Ct is the concentration of congener /', and
TEFi is the TEF of congener /'. The TEQ value is used in the appropriate equation for average
daily intake (ADIiEq), which is then used in the appropriate risk equation (e.g., Equations 2 and
3):
Eq. (2)
CR = CSFMS_TCDD • ADITEQ Eq. (3)
where HQ is the hazard quotient, RFD is the reference dose, CR is the cancer risk, and CSF is the
cancer slope factor.
3. The TEF values for individual congeners reflect, to varying degrees, contributions of
bioavailability and toxicokinetics to toxic potency (i.e., to the extent that the derivation of
the TEF is informed by results of in vivo and/or ingestion bioassays).
4. The TEF methodology introduces several complexities into the adjustment of soil dioxin
risk to account for RBA of dioxins in soil.
a. Ideally, estimates of soil RBA for each congener would be needed to account for
congener-specific RBA (e.g., Equation 4):
TEQ = 2 C • TEFi • RBAt Eq. (4)
where RBAt is the soil RBA for congener /'.
b. A less desirable approach would be to apply an estimate of the soil RBA for 2,4,7,8-
TCDD to all congeners. This would introduce uncertainty into the risk estimate to the
extent that RBA varies across congeners (e.g., Equations 5 and 6):
01/05/10 PageA-v SRC/Klotzbach
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Eq. (5)
CR — CSF2/it7tS_TCDD • AD1TEQ • RBA2^Af7fS_TCDD Eq. (6)
01/05/10 PageA-vi SRC/Klotzbach
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LITERATURE SEARCH PRODUCT
BIO AVAILABILITY OF DIOXINS IN SOIL
1.0 Bioavailability and Pharmacokinetics Studies in Humans
1.1 Soil
No literature identified.
1.2 Other Media
Abraham K, Hille A, Ende M, et al. 1994. Intake and fecal excretion of PCDDs, PCDFs, HCB
and PCBs (138,153,180) in a breast-fed and a formula-fed infant. Chemosphere 29:2279-2286.
Abraham K, Knoll A, Ende M, et al. 1996. Intake, fecal excretion, and body burden of
polychlorinated dibenzo-p-dioxins and dibenzofurans in breast-fed and formula-fed infants.
Pediatr Res 40:671-679.
Dahl P, Lindstrom G, Wiberg K, et al. 1995. Absorption of polychlorinated biphenyls, dibenzo-
p-dioxins and dibenzofurans by breast-fed infants. Chemosphere 30:2297-2306.
McLachlan MS. 1993. Digestive tract absorption of polychlorinated dibenzo-p-dioxins,
dibenzofurans, and biphenyls in a nursing infant. Toxicol Appl Pharmacol 123:68-72.
Pluim HJ, Wever J, Koppe JG, et al. 1993. Intake and faecal excretion of chlorinated dioxins and
dibenzofurans in breast-fed infants at different ages. Chemosphere 26:1947-1952.
Poiger H, Schlatter C. 1986. Pharmacokinetics of 2,3,7,8-TCDD in man. Chemosphere 15:1489-
1494.
Rohde S, Moser GA, Papke O, et al. 1999. Clearance of PCDD/Fs via the gastrointestinal tract in
occupationally exposed persons. Chemosphere 38(14):3397-3410.
Schlummer M, Moser GA, McLachlan MS. 1998. Digestive tract absorption of PCDD/Fs, PCBs,
and HCB in humans: Mass balances and mechanistic considerations. Toxicol Appl Pharmacol
152(1):128-137.
2.0 Bioavailability and Pharmacokinetics Studies in Animals
2.1 Soil
Rats
Budinsky RA, Rowlands JC, Casteel S, et al. 2008. A pilot study of oral bioavailability of
dioxins and furans from contaminated soils: Impact of differential hepatic enzyme activity and
species differences. Chemosphere 70(10): 1774-1786.
01/05/10 PageA-1 SRC/Klotzbach
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McConnell EE, Lucier GW, Rumbaugh RC, et al. 1984. Dioxin in soil: Bioavailability after
ingestion by rats and guinea pigs. Science 223:1077-1079.
Guinea Pigs
McConnell EE, Lucier GW, Rumbaugh RC, et al. 1984. Dioxin in soil: Bioavailability after
ingestion by rats and guinea pigs. Science 223:1077-1079.
Umbreit TH, Hesse EJ, Gallo MA. 1986a. Bioavailability of dioxin in soil from a 2,4,5-T
manufacturing site. Science 232:497-499.
Swine
Budinsky RA, Rowlands JC, Casteel S, et al. 2008. A pilot study of oral bioavailability of
dioxins and furans from contaminated soils: Impact of differential hepatic enzyme activity and
species differences. Chemosphere 70(10): 1774-1786.
Wittsiepe J, Erlenkamper B, Welge P, et al. 2007. Bioavailability of PCDD/F from contaminated
soil in young Goettingen mini-pigs. Chemosphere 67(9):S355-S364.
Cows
Jones D, Safe E, Morcum E, et al. 1989. Bioavailability of grain and soil-borne tritiated
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) administered to lactating Holstein cows.
Chemosphere 18:1257-1263.
Chickens
Petreas M, Ruble R, Visita P, et al. 1996. Bioaccumulation of PCDD/Fs from soil by foraging
chickens. Organohalogen Compounds 29:51-54.
2.2 Other Media
Rats
Abraham K, Weberrub U, Wiesmuller T, et al. 1989a. Comparative studies on absorption and
distribution in the liver and adipose tissue of PCDDs and PCDFs in rats and marmoset monkeys.
Chemosphere 19:887-892.
Abraham K, Wiesmuller T, Brunner H, et al. 1989b. Absorption and tissue distribution of
various polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs and PCDFs) in the rat.
Arch Toxicol 63:193-202.
Abraham K, Wiesmuller T, Brunner H, et al. 1989c. Elimination of various polychlorinated
dibenzo-p-dioxins and dibenzofurans (PCDDs and PCDFs) in rat feces. Arch Toxicol 63:75-78.
01/05/10 PageA-2 SRC/Klotzbach
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Allen JR, Van Miller JP, Norback DH. 1975. Tissue distribution, excretion and biological effects
of [14C]tetrachlorodibenzo-p-dioxin in rats. Food Cosmet Toxicol 13:501-505.
Birnbaum LS, Couture LA. 1988. Disposition of octachlorodibenzo-p-dioxin (OCDD) in male
rats. Toxicol Appl Pharmacol 93:22-30.
Chen CY, Hamm JT, Hass JR, et al. 2001. Disposition of polychlorinated dibenzo-p-dioxins,
dibenzofurans, and non-ortho polychlorinated biphenyls in pregnant Long Evans rats. Toxicol
Appl Pharmacol 173 (2): 6 5-8 8.
Diliberto JJ, Jackson JA, Birnbaum LS. 1996. Comparison of 2,3,7,8-tetrachlorodibenzo-p-
dioxin (TCDD) disposition following pulmonary, oral, dermal and parenteral exposures to rats.
Toxicol Appl Pharmacol 138:158-168.
Diliberto JJ, Kedderis LB, Jackson JA, et al. 1993. Effects of dose and routes of exposure on the
disposition of 2,3,7,8-((3)H)tetrabromodibenzo-p-dioxin (TBDD) in the rat. Toxicol Appl
Pharmacol 120(2): 315-3 26.
Fries GF, Marrow GS. 1975. Retention and excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin by
rats. J Agric Food Chem 23:265-269.
Hakk H, Larsen G, Feil V. 2001. Tissue distribution, excretion, and metabolism of 1,2,7,8-
tetrachlorodibenzo-p-dioxin in the rat. Chemosphere 42(8):975-983.
Hebert CD, Birnbaum LS. 1987. The influence of aging on intestinal absorption of TCDD in
rats. Toxicol Lett 37:47-55.
Hurst CH, DeVito MJ, Birnbaum LS. 2000. Tissue disposition of 2,3,7,8-tetrachlorodibenzo-p-
dioxin (TCDD) in maternal and developing Long-Evans rats. Toxicol Sci 57(2):275-283.
Huwe JK, Feil VJ, Larsen GL, et al. 1998. Metabolism and disposition of 1,4,7,8-
tetrachlorodibenzo-p-dioxin in rats. Chemosphere 37(9-12): 1885-1893. Erratum in:
Chemosphere 38(8): 1957-1958.
Kedderis LB, Diliberto JJ, Jackson JA, et al. 1992. Effects of dose and route of exposure on
dioxin disposition. Chemosphere 25(l-2):7-10.
Krowke R, Chahoud I, Baumann-Wilschke I, et al. 1989. Pharmacokinetics and biological
activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin: 2. Pharmacokinetics in rats using a loading-
dose/maintenance-dose regime with high doses. Arch Toxicol 63:356-360.
Lakshmanan MR, Campbell BS, Chirtel SJ, et al. 1986. Studies on the mechanism of absorption
and distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the rat. J Pharmacol Exp Ther
239:673-677.
01/05/10 PageA-3 SRC/Klotzbach
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Li X, Weber LWD, Rozman KK. 1995. Toxicokientics of 2,3,7,8-tetrachlorodibenzo-p-dioxin in
female Sprague-Dawley rats including placental and lactational transfer to fetuses and neonates.
Fund Appl Toxicol 27:70-76.
Norback DH, Engblom JF, Allen JR. 1975. Tissue distribution and extraction of
octachlorodibenzopara-dioxin in the rat. Toxicol Appl Pharmacol 32:330-338.
Piper WN, Rose RQ, Gehring PJ. 1973. Excretion and tissue distribution of 2,3,7,8-
tetrachlorodibenzo-p-dioxin in the rat. Environ Health Perspect 5:241-244.
Poiger H, Schlatter C. 1980. Influence of solvents and adsorbents on dermal and intestinal
absorption of TCDD. Food Cosmet Toxicol 18:477-481.
Rose JQ, Ramsey JC, Wentzler TH, et al. 1976. The fate of 2,3,7,8-tetrachlorodibenzo-p-dioxin
following single and repeated oral doses to the rat. Toxicol Appl Pharmacol 36:209-226.
Van den Berg M, Olie K, Hutzinger O. 1983. Uptake and selection in rats of orally administered
chlorinated dioxins and dibenzofurans from fly-ash and fly-ash extract. Chemosphere 12:537-
544.
Van den Berg M, de Vroom E, van Greevenbroek M, et al. 1985. Bioavailability of PCDDs and
PCDFs absorbed on fly ash in rat, guinea pig and Syrian golden hamster. Chemosphere 14:865-
869.
Van den Berg M, Van Greevenbroek M, Olie K, et al. 1986. Bioavailability of polychlorinated
dibenzo-p-dioxins and polychlorinated dibenzofurans on fly ash after semi-chronic oral ingestion
by the rat. Chemosphere 15:509-518.
Van den Berg M, Sinke M, Wever H. 1987. Vehicle dependent bioavailability of polychlorinated
dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in the rat. Chemosphere 16:1193-1203.
Wacker R, Poiger H, Schlatter C. 1986. Pharmacokinetics and metabolism of 1,2,3,7,8-
pentachlorodibenzo-p-dioxin in the rat. Chemosphere 15:1473-1476.
Mice
Gasiewicz TA, Geiger LE, Rucci G, et al. 1983. Distribution, excretion, and metabolism of
2,3,7,8-tetrachlorodibenzo-p-dioxin in C57BL/6J, DBA/2J, and B6D2F1/J mice. Drug Metab
Dispos 11:397-403.
Koshakji RP, Harbison RD, Bush MT. 1984. Studies on the metabolic fate of [14C]2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD) in the mouse. Toxicol Appl Pharmacol 73:69-77.
01/05/10 PageA-4 SRC/Klotzbach
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Guinea Pigs
Gasiewicz TA, Neal RA. 1979. 2,3,7,8-Tetrachlorodibenzo-p-dioxin tissue distribution,
excretion, and effects on clinical parameters in guinea pigs. Toxicol Appl Pharmacol 51:329-
339.
Nolan RJ, Smith FA, Hefner JG. 1979. Elimination and tissue distribution of 2,3,7,8-
tetrachlorodibenzo- p-dioxin (TCDD) in female guinea pigs following a single oral dose. Toxicol
Appl Pharmacol 48:A162.
Olson JR. 1986. Metabolism and disposition of 2,3,7,8-tetrachlorodibenzo-p-dioxin in guinea
pigs. Toxicol Appl Pharmacol 85:263-273.
Olson JR, Gasiewicz TA, Neal RA, et al. 1980. Tissue distribution excretion, and metabolism of
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the Golden Syrian Hamster. Toxicol Appl
Pharmacol 56:78-85.
Poiger H, Weber H, Schlatter CH. 1982. Special aspects of metabolism and kinetics of TCDD in
dogs and rats: Assessment of toxicity of TCDD-metabolites(s) in guinea pigs. In: Hutzinger O,
Frei RW, Merian E, et al., eds. Chlorinated dioxins and related compounds: Impact on the
environment. New York, NY: Pergamon Press, 317-325.
Van den Berg M, de Vroom E, van Greevenbroek M, et al. 1985. Bioavailability of PCDDs and
PCDFs absorbed on fly ash in rat, guinea pig and Syrian golden hamster. Chemosphere 14:865-
869.
Hamsters
Van den Berg M, de Vroom E, van Greevenbroek M, et al. 1985. Bioavailability of PCDDs and
PCDFs absorbed on fly ash in rat, guinea pig and Syrian golden hamster. Chemosphere 14:865-
869.
Swine
Cavret S, Laurent C, Feidt C, et al. 2003. Intestinal absorption of 14C from 14C-phenanthrene,
14C-benzo[a]pyrene and 14C-tetrachlorodibenzo-para-dioxin. Reprod Nutr Dev 43(2):145-154.
Laurent C, Feidt C, Grova N, et al. 2002. Portal absorption of 14C after ingestion of spiked milk
with 14C-phenanthrene, 14C-benzo[a]pyrene or 14C-TCDD in growing pigs. Chemosphere
48(8):843-848.
Cows
Feil VJ, Huwe JK, Zaylskie RG, et al. 2000. Chlorinated dibenzo-p-dioxin and dibenzofuran
concentrations in beef animals from a feeding study. J Agric Food Chem 48:6163-6173.
01/05/10 PageA-5 SRC/Klotzbach
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Richter W, McLachlan MS. 2001. Uptake and transfer of PCDD/Fs by cattle fed naturally
contaminated feedstuffs and feed contaminated as a result of sewage sludge application. 2.
Nonlactating cows. J Agric Food Chem 49:5857-5865.
Slob W, Oiling M, Derks JJGM, et al. 1995. Congener-specific bioavailability of PCDD/Fs and
co-planar PCBs in cows: Laboratory and field measurements. Chemosphere 31:3827-3838.
Monkeys
Abraham K, Weberrub U, Wiesmuller T, et al. 1989a. Comparative studies on absorption and
distribution in the liver and adipose tissue of PCDDs and PCDFs in rats and marmoset monkeys.
Chemosphere 19:887-892.
3.0 Toxicity Studies of Dioxin in Soil in Animals
Rats
Lucier GW, Rumbaugh RC, McCoy Z, et al. 1986. Ingestion of soil contaminated with 2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD) alters hepatic enzyme activities in rats. Fundam Appl
Toxicol 6:364-371.
Mice
Umbreit TH, Hesse EJ, Gallo MA. 1987. Reproductive toxicity in female mice of dioxin-
contaminated soils from a 2,4,5-trichlorophenoxyacetic acid manufacturing site. Arch Environ
Contam Toxicol 16:461^66.
Umbreit TH, Hesse EJ, Gallo MA. 1988. Reproductive studies of C57B/6 male mice treated with
TCDD-contaminated soils from a 2,4,5-trichlorophenoxyacetic acid manufacturing site. Arch
Environ Contam Toxicol 17:145-150.
Guinea Pigs
Umbreit TH, Patel D, Gallo MA. 1985. Acute toxicity of TCDD contaminated soil from an
industrial site. Chemosphere 14:945-947.
Umbreit TH, Hesse EJ, Gallo MA. 1986. Comparative toxicity of TCDD contaminated soil from
Times Beach, Missouri, and Newark, New Jersey. Chemosphere 15:2121-2124.
4.0 In Vitro Bioaccessibility
Cavret S, Laurent C, Feidt C, et al. 2003. Intestinal absorption of 14C from 14C-phenanthrene,
14C-benzo[a]pyrene and 14C-tetrachlorodibenzo-para-dioxin. Reprod Nutr Dev 43(2):145-154.
01/05/10 PageA-6 SRC/Klotzbach
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Ruby MV, Fehling KA, Paustenbach DJ, et al. 2002. Oral bioaccessibility of dioxins/furans at
low concentrations (50-350 ppttoxicity equivalent) in soil. Environ Sci Technol 36(22):4905-
4911.
5.0 PBPK Modeling
Carrier G, Brunet RC, Brodeur J. 1995. Modeling of the toxicokinetics of polychlorinated
dibenzo-p-dioxins and dibenzofurans in mammalians, including humans. II. Kinetics of
absorption and disposition of PCDD/Fs. Toxicol Appl Pharmacol 131:267-276.
Kerger BD, Leung HW, Scott PK, et al. 2007a. An adaptable internal dose model for risk
assessment of dietary and soil dioxin exposures in young children. Toxicol Sci 100(l):224-237.
Kerger BD, Leung HW, Scott PK, et al. 2007b. Refinements on the age-dependent half-life
model for estimating child body burdens of polychlorodibenzodioxins dibenzofurans.
Chemosphere 67(9):S272-S278.
Leung H-W, Ku RH, Paustenbach DJ, et al. 1988. A physiologically based pharmacokinetic
model for 2,3,7,8-tetrachlorodibenzo-p-dioxin in C57BL/6J and DBA/2J mice. Toxicol Letters
42:15-28.
Leung H-W, Paustenbach DJ, Murray FJ, et al. 1990. A physiological pharmacokinetic
description of the tissue distribution and enzyme-inducing properties of 2,3,7,8-
tetrachlorodibenzo-p-dioxin in the rat. Toxicol Appl Pharmacol 103:399-410.
Maruyama W, Yoshida K, Tanaka T, et al. 2002. Determination of tissue-blood partition
coefficients for a physiological model for humans, and estimation of dioxin concentration in
tissues. Chemosphere 46:975-985.
Wang X, Santostefano MJ, Evans MV, et al. 1997. Determination of parameters responsible for
pharmacokinetic behavior of TCDD in female Sprague-Dawley rats. Toxicol Appl Pharmacol
6.0 Risk Assessments
Ahlborg UG, Hanberg A. 1992. Toxicokinetics of PCDDs and PCDFs of importance to the
development of human risk assessment. Toxic Substances Journal 12:197-211.
DeVito MJ, Birnbaum LS. 1995. The importance of pharmacokinetics in determining the relative
potency of 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,3,7,8-tetrachlorodibenzofuran. Fundam
Appl Toxicol 24: 145-148.
Eschenroeder A, Jaeger RJ, Ospital JJ, et al. 1986. Health risk analysis of human exposures to
soil amended with sewage sludge contaminated with polychlorinated dibenzodioxins and
dibenzofurans. Vet Hum Toxicol 28:435-442.
01/05/10 PageA-7 SRC/Klotzbach
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Gough M. 1991. Human exposure from dioxin in soil-a meeting report. J Toxicol Environ Health
32:205-245.
Kimbrough RD, FalkH, Stehr P, et al. 1984. Health implications of 2,3,7,8-tetrachlorodibenzo-
p-dioxin (TCDD) contamination of residential soil. J Toxicol Environ Health 14:47-93.
Paustenbach DJ, Shu HP, Murray FJ. 1986. A critical examination of assumptions used in risk
assessments of dioxin contaminated soil. Regul Toxicol Pharmacol 6:284-307.
Paustenbach DJ, Wenning RJ, Lau V, et al. 1992. Recent developments on the hazards posed by
2,3,7,8-tetrachlorodibenzo-p-dioxin in soil: Implications for setting risk-based cleanup levels at
residential and industrial sites. J Toxicol Environ Health 36(2): 103-150.
Paustenbach DJ, Fehling K, Scott P, et al. 2006. Identifying soil cleanup criteria for dioxins in
urban residential soils: How have 20 years of research and risk assessment experience affected
the analysis? J Toxicol Environ Health B Crit Rev 9(2):87-145.
Pohl H, DeRosa C, Holler J. 1995. Public health assessment for dioxins exposure from soil.
Chemosphere 31(l):2437-2454.
7.0 Reviews
Gasiewicz TA, Olson RJ, GeigerLE, et al. 1983b. Absorption, distribution, and metabolism of
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in experimental animals. In: Tucker RE, Young
AL, Gray AP, eds. Human and environmental risk of chlorinated dioxins and related compounds.
New York, London: Plenum Press, 495-525.
Haws LC, Su SH, Harris M, et al. 2006. Development of a refined database of mammalian
relative potency estimates for dioxin-like compounds. Toxicol Sci 89(1):4-30.
Hong B, Garabrant D, Hedgeman E, et al. 2009. Impact of WHO 2005 revised toxic equivalency
factors for dioxins on the TEQs in serum, household dust and soil. Chemosphere 76(6):727-733.
Olson J. 1993. Health assessment for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related
compounds. Chapter 1. Disposition and pharmacokinetics. Govt Reports Announcements &
Index (GRA&I), Issue 22. U.S. Environmental Protection Agency, Office of Health and
Environmental Assessment: Washington, DC.
Van den Berg M, De Jongh J, Poiger H, et al. 1994. The toxicokinetics and metabolism of
polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and their relevance to
toxicity. Crit Rev Toxicol 24:1-74.
Van den Berg M, Birnbaum LS, Denison M, et al. 2006. The 2005 World Health Organization
reevaluation of human and mammalian toxic equivalency factors for dioxins and dioxin-like
compounds. Toxicol Sci 93(2):223-241.
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Appendix B - RBA Data
-------
1
2
3
4
5
6
7
8
Study Study
Code
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Species Test
Material
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
TM Congener Cl Dose
Code #
1 2,3,7,8- D 4 4.13
TCDD
1 1,2,3,7,8- D 5 17.8
PeCDD
1 1,2,3,4,7,8- D 6 25.1
HxCDD
1 1,2,3,6,7,8- D 6 51.8
HxCDD
1 1,2,3,7,8,9- D 6 43.7
HxCDD
1 1,2,3,4,6,7, D 7 291
8-HpCDD
1 OCDD D 8 348
1 2,3,7,8- F 4 162
TCDF
+/- SD Unit RBA +/-
#NA pg/kg- 2.0 #NA
day
#NA pg/kg- 31.7 #NA
day
#NA pg/kg- 23.6 #NA
day
#NA pg/kg- 21.1 #NA
day
#NA pg/kg- 19.7 #NA
day
#NA pg/kg- 24.3 #NA
day
#NA pg/kg- 39.8 #NA
day
#NA pg/kg- 24.1 #NA
day
SD Test
Material
Dosing
Protocol
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
Reference
Material
Dosing
Protocol
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
Bioavailability Test
Metric Material
Vehicle
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
Referent
Vehicle
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
-------
9
10
11
12
13
14
15
16
Study Study
Code
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Species Test
Material
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
TM Congener Cl Dose
Code #
1 1,2,3,7,8- F 5 413
PeCDF
1 2,3,4,7,8- F 5 202
PeCDF
1 1,2,3,4,7,8- F 6 971
HxCDF
1 1,2,3,6,7,8- F 6 736
HxCDF
1 2,3,4,6,7,8- F 6 146
HxCDF
1 1,2,3,7,8,9- F 6 146
HxCDF
1 1,2,3,4,6,7, F 7 3559
8-HpCDF
1 1,2,3,4,7,8, F 7 1375
9-HpCDF
+/- SD Unit RBA +/-
#NA pg/kg- 22.8 #NA
day
#NA pg/kg- 34.4 #NA
day
#NA pg/kg- 40.9 #NA
day
#NA pg/kg- 31.5 #NA
day
#NA pg/kg- 39.4 #NA
day
#NA pg/kg- 28.6 #NA
day
#NA pg/kg- 28.5 #NA
day
#NA pg/kg- 28.0 #NA
day
SD Test
Material
Dosing
Protocol
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
Reference
Material
Dosing
Protocol
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
Bioavailability Test
Metric Material
Vehicle
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
adipose+blood Dougball
+brain+liver+
muscle burden
Referent
Vehicle
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
-------
17
18
19
20
21
22
23
24
Study Study
Code
Wittsiepeet WI07
al. 2007
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Species Test
Material
Swine Sludge-
treated
soil
Swine Urban
soil
Swine Urban
soil
Swine Urban
soil
Swine Urban
soil
Swine Urban
soil
Swine Flood-
plain soil
Swine Flood-
plain soil
TM
Code
1
1
1
1
1
1
2
2
Congener Cl Dose
#
OCDF F 8 9706
2,3,7,8- D 4 70
TCDD
1,2,3,7,8- D 5 36
PeCDD
1,2,3,6,7,8- D 6 39
HxCDD
1,2,3,4,6,7, D 7 621
8-HpCDD
2,3,4,7,8- F 5 19
PeCDF
2,3,7,8- F 4 1120
TCDF
1,2,3,7,8- F 5 561
PeCDF
+/- SD Unit RBA +/-
#NA pg/kg- 42.2 #NA
day
2.0 SD pg/kg- 18 8
day
1.0 SD pg/kg- 24 10
day
1.0 SD pg/kg- 38 21
day
21 SD pg/kg- 55 13
day
1.0 SD pg/kg- 32 9
day
45 SD pg/kg- 22 4
day
23 SD pg/kg- 30 13
day
SD Test
Material
Dosing
Protocol
28-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
Reference
Material
Dosing
Protocol
28-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
Bioavailability
Metric
Liver +
adipose burden
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Test
Material
Vehicle
Dougball
Dougball
Dougball
Dougball
Dougball
Dougball
Dougball
Dougball
Referent
Vehicle
Hexane/
acetone
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
-------
25
26
27
28
29
30
31
32
Study Study
Code
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Species Test
Material
Swine Flood-
plain soil
Swine Flood-
plain soil
Swine Flood-
plain soil
Rat Urban
soil
Rat Urban
soil
Rat Urban
soil
Rat Urban
soil
Rat Urban
soil
TM Congener Cl Dose
Code #
2 2,3,4,7,8- F 5 460
PeCDF
2 1,2,3,4,7,8- F 6 375
HxCDF
2 1,2,3,6,7,8- F 6 85
HxCDF
1 2,3,7,8- D 4 302
TCDD
1 1,2,3,7,8- D 5 172
PeCDD
1 1,2,3,6,7,8- D 6 247
HxCDD
1 1,2,3,4,6,7, D 7 4820
8-HpCDD
1 2,3,4,7,8- F 5 100
PeCDF
+/- SD Unit RBA +/-
18 SD pg/kg- 27 2
day
15 SD pg/kg- 35 2
day
3.0 SD pg/kg- 37 2
day
17 SD pg/kg- 35 4
day
10 SD pg/kg- 40 3
day
14 SD pg/kg- 47 3
day
270 SD pg/kg- 34 2
day
6.0 SD pg/kg- 40 2
day
SD Test
Material
Dosing
Protocol
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
Reference
Material
Dosing
Protocol
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
Bioavailability Test
Metric Material
Vehicle
Liver + Dougball
adipose burden
(ND=l/2 DL)
Liver + Dougball
adipose burden
(ND=l/2 DL)
Liver + Dougball
adipose burden
(ND=l/2 DL)
Liver + Feed
adipose burden
(ND=l/2 DL)
Liver + Feed
adipose burden
(ND=l/2 DL)
Liver + Feed
adipose burden
(ND=l/2 DL)
Liver + Feed
adipose burden
(ND=l/2 DL)
Liver + Feed
adipose burden
(ND=l/2 DL)
Referent
Vehicle
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
-------
33
34
35
36
37
38
39
40
Study Study
Code
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Flood-
plain soil
Rat Flood-
plain soil
Rat Flood-
plain soil
Rat Flood-
plain soil
Rat Flood-
plain soil
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
TM Congener Cl Dose
Code #
2 2,3,7,8- F 4 6430
TCDF
2 1,2,3,7,8- F 5 3920
PeCDF
2 2,3,4,7,8- F 5 3370
PeCDF
2 1,2,3,4,7,8- F 6 2630
HxCDF
2 1,2,3,6,7,8- F 6 649
HxCDF
1 2,3,7,8- D 4 32.8
TCDD
1 1,2,3,7,8- D 5 350
PeCDD
1 1,2,3,4,7,8- D 6 330
HxCDD
+/- SD Unit RBA +/-
370 SD pg/kg- 89 12
day
230 SD pg/kg- 58 5
day
200 SD pg/kg- 52 3
day
150 SD pg/kg- 57 3
day
38 SD pg/kg- 56 4
day
#NA pg/kg- #NA #NA
day
#NA pg/kg- #NA #NA
day
#NA pg/kg #NA #NA
SD Test
Material
Dosing
Protocol
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
Single
gavage
dose,
aqueous
suspension
Single
gavage
dose,
aqueous
suspension
Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Feed
Feed
Feed
Feed
Feed
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil
Corn oil
Corn oil
-------
41
42
43
44
45
46
47
48
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
TM Congener Cl Dose
Code #
1 1,2,3,6,7,8- D 6 1070
HxCDD
1 1,2,3,7,8,9- D 6 1184
HxCDD
1 1,2,3,4,6,7, D 7 756
8-HpCDD
1 OCDD D 8 20200
1 2,3,7,8- F 4 2560
TCDF
1 1,2,3,7,8- F 5 22000
PeCDF
1 2,3,4,7,8- F 5 11260
PeCDF
1 1,2,3,4,7,8- F 6 66400
HxCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg 22 5 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 27 5 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 26 6 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 18 4 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 23 5 SD Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
49
50
51
52
53
54
55
56
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 1
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
TM Congener Cl Dose +/- SD Unit
Code #
1 1,2,3,6,7,8- F 6 57000 #NA pg/kg
HxCDF
1 1,2,3,7,8,9- F 6 27200 #NA pg/kg
HxCDF
1 2,3,4,6,7,8- F 6 24600 #NA pg/kg
HxCDF
1 1,2,3,4,6,7, F 7 458000 #NA pg/kg
8-HpCDF
1 1,2,3,4,7,8, F 7 166600 #NA pg/kg
9-HpCDF
1 OCDF F 8 4140000 #NA pg/kg
2 2,3,7,8- D 4 346 #NA pg/kg
TCDD
2 1,2,3,7,8- D 5 1480 #NA pg/kg
PeCDD
RBA +/- SD Test
Material
Dosing
Protocol
22 5 SD Single
gavage
dose,
aqueous
suspension
5 1 SD Single
gavage
dose,
aqueous
suspension
10 2 SD Single
gavage
dose,
aqueous
suspension
13 3 SD Single
gavage
dose,
aqueous
suspension
14 3 SD Single
gavage
dose,
aqueous
suspension
10 3 SD Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
100 10 SD Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
57
58
59
60
61
62
63
64
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
TM Congener Cl Dose
Code #
2 1,2,3,4,7,8- D 6 1258
HxCDD
2 1,2,3,6,7,8- D 6 2900
HxCDD
2 1,2,3,7,8,9- D 6 3120
HxCDD
2 1,2,3,4,6,7, D 7 2120
8-HpCDD
2 OCDD D 8 60400
2 2,3,7,8- F 4 28600
TCDF
2 1,2,3,7,8- F 5 80600
PeCDF
2 2,3,4,7,8- F 5 47200
PeCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg 74 6 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 67 6 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 46 4 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 32 4 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 23 3 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 76 9 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 89 9 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 50 4 SD Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
65
66
67
68
69
70
71
72
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 2
FI09 Rat Surface
soil 3
TM Congener Cl Dose +/- SD Unit
Code #
2 1,2,3,4,7,8- F 6 198000 #NA pg/kg
HxCDF
2 1,2,3,6,7,8- F 6 168600 #NA pg/kg
HxCDF
2 1,2,3,7,8,9- F 6 80000 #NA pg/kg
HxCDF
2 2,3,4,6,7,8- F 6 76800 #NA pg/kg
HxCDF
2 1,2,3,4,6,7, F 7 994000 #NA pg/kg
8-HpCDF
2 1,2,3,4,7,8, F 7 394000 #NA pg/kg
9-HpCDF
2 OCDF F 8 6500000 #NA pg/kg
3 2,3,7,8- D 4 418 #NA pg/kg
TCDD
RBA +/- SD Test
Material
Dosing
Protocol
61 6 SD Single
gavage
dose,
aqueous
suspension
59 5 SD Single
gavage
dose,
aqueous
suspension
16 2 SD Single
gavage
dose,
aqueous
suspension
32 3 SD Single
gavage
dose,
aqueous
suspension
28 3 SD Single
gavage
dose,
aqueous
suspension
34 3 SD Single
gavage
dose,
aqueous
suspension
21 3 SD Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
73
74
75
76
77
78
79
80
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
TM
Code
3
3
3
3
3
3
3
3
Congener Cl Dose
#
1,2,3,7,8- D 5 1446
PeCDD
1,2,3,4,7,8- D 6 1116
HxCDD
1,2,3,6,7,8- D 6 2760
HxCDD
1,2,3,7,8,9- D 6 3000
HxCDD
1,2,3,4,6,7, D 7 1824
8-HpCDD
OCDD D 8 47400
2,3,7,8- F 4 36800
TCDF
1,2,3,7,8- F 5 75200
PeCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg 79 12 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 52 10 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 46 7 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 32 5 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 20 4 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 75 7 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 69 8 SD Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
81
82
83
84
85
86
87
88
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
FI09 Rat Surface
soil 3
TM
Code
3
3
3
3
3
3
3
3
Congener Cl Dose +/- SD Unit RBA +/-
#
2,3,4,7,8- F 5 43600 #NA pg/kg 44 6
PeCDF
1,2,3,4,7,8- F 6 158200 #NA pg/kg 42 6
HxCDF
1,2,3,6,7,8- F 6 128200 #NA pg/kg 42 6
HxCDF
1,2,3,7,8,9- F 6 60000 #NA pg/kg 13 2
HxCDF
2,3,4,6,7,8- F 6 61800 #NA pg/kg 22 3
HxCDF
1,2,3,4,6,7, F 7 680000 #NA pg/kg 18 3
8-HpCDF
1,2,3,4,7,8, F 7 294000 #NA pg/kg 22 3
9-HpCDF
OCDF F 8 4160000 #NA pg/kg 13 2
SD Test
Material
Dosing
Protocol
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
89
90
91
92
93
94
95
96
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
TM Congener Cl Dose
Code #
4 2,3,7,8- D 4 19.54
TCDD
4 1,2,3,7,8- D 5 76.2
PeCDD
4 1,2,3,4,7,8- D 6 66
HxCDD
4 1,2,3,6,7,8- D 6 226
HxCDD
4 1,2,3,7,8,9- D 6 260
HxCDD
4 1,2,3,4,6,7, D 7 151.4
8-HpCDD
4 OCDD D 8 5380
4 2,3,7,8- F 4 2060
TCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 82 #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 81 10 SD Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
97
98
99
100
101
102
103
104
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 4
TM Congener Cl Dose
Code #
4 1,2,3,7,8- F 5 3860
PeCDF
4 2,3,4,7,8- F 5 2080
PeCDF
4 1,2,3,4,7,8- F 6 11340
HxCDF
4 1,2,3,6,7,8- F 6 9340
HxCDF
4 1,2,3,7,8,9- F 6 4400
HxCDF
4 2,3,4,6,7,8- F 6 4200
HxCDF
4 1,2,3,4,6,7, F 7 90600
8-HpCDF
4 1,2,3,4,7,8, F 7 27600
9-HpCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg 74 9 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 52 8 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 63 8 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 62 8 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 19 3 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 28 3 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 33 4 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 39 5 SD Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
105
106
107
108
109
110
111
112
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 4
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
TM
Code
4
5
5
5
5
5
5
5
Congener Cl Dose +/- SD Unit
#
OCDF F 8 1253333 #NA pg/kg
2,3,7,8- D 4 #NA #NA pg/kg
TCDD
1,2,3,7,8- D 5 15.56 #NA pg/kg
PeCDD
1,2,3,4,7,8- D 6 13.6 #NA pg/kg
HxCDD
1,2,3,6,7,8- D 6 40.6 #NA pg/kg
HxCDD
1,2,3,7,8,9- D 6 44.8 #NA pg/kg
HxCDD
1,2,3,4,6,7, D 7 23.6 #NA pg/kg
8-HpCDD
OCDD D 8 840 #NA pg/kg
RBA +/- SD Test
Material
Dosing
Protocol
27 3 SD Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
113
114
115
116
117
118
119
120
Study
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Finley et al.
2009
Study Species Test
Code Material
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
TM
Code
5
5
5
5
5
5
5
5
Congener Cl Dose
#
2,3,7,8- F 4 338
TCDF
1,2,3,7,8- F 5 847
PeCDF
2,3,4,7,8- F 5 464
PeCDF
1,2,3,4,7,8- F 6 2360
HxCDF
1,2,3,6,7,8- F 6 2040
HxCDF
1,2,3,7,8,9- F 6 968
HxCDF
2,3,4,6,7,8- F 6 830
HxCDF
1,2,3,4,6,7, F 7 14460
8-HpCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 61 18 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 56 15 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 47 13 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 42 11 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 23 #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 19 7 SD Single
gavage
dose,
aqueous
suspension
Reference Bioavailability
Material Metric
Dosing
Protocol
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Single Liver burden
gavage dose
in com oil,
3 dose
levels
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
121
122
123
124
125
126
127
128
Study
Finley et al.
2009
Finley et al.
2009
Shu et al.
1988
Shu et al.
1988
Shu et al.
1988
Shu et al.
1988
Shu et al.
1988
Shu et al.
1988
Study Species Test
Code Material
FI09 Rat Surface
soil 5
FI09 Rat Surface
soil 5
SH88 Rat Surface
soil -
Times
Beach
SH88 Rat Surface
soil -
Times
Beach
SH88 Rat Surface
soil -
Times
Beach
SH88 Rat Surface
soil -
Times
Beach
SH88 Rat Surface
soil -
Times
Beach
SH88 Rat Surface
soil -
Times
Beach
TM
Code
5
5
1
1
1
1
1
1
Congener Cl Dose +/- SD Unit
#
1,2,3,4,7,8, F 7 4680 #NA pg/kg
9-HpCDF
OCDF F 8 105333 #NA pg/kg
2,3,7,8- D 4 3200 #NA pg/kg
TCDD
2,3,7,8- D 4 7000 #NA pg/kg
TCDD
2,3,7,8- D 4 40000 #NA pg/kg
TCDD
2,3,7,8- D 4 37000 #NA pg/kg
TCDD
2,3,7,8- D 4 175000 #NA pg/kg
TCDD
2,3,7,8- D 4 1450000 #NA pg/kg
TCDD
RBA +/- SD Test
Material
Dosing
Protocol
25 8 SD Single
gavage
dose,
aqueous
suspension
13 5 SD Single
gavage
dose,
aqueous
suspension
57 #NA Single
gavage
dose,
aqueous
suspension
64 #NA Single
gavage
dose,
aqueous
suspension
49 #NA Single
gavage
dose,
aqueous
suspension
56 #NA Single
gavage
dose,
aqueous
suspension
59 #NA Single
gavage
dose,
aqueous
suspension
48 #NA Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
-------
129
130
131
Study Study
Code
Lucieretal. LU86
1986
Lucieretal. LU86
1986
Bonaccorsi BO84
etal. 1984
Species Test
Material
Rat Surface
soil -
Minker
MO
Rat Surface
soil -
Minker
MO
Rabbit Surface
soil -
Sevaso
TM Congener
Code
1 2,3,7,8-
TCDD
1 2,3,7,8-
TCDD
1 2,3,7,8-
TCDD
Cl Dose +/- SD Unit RBA +/-
#
D 4 1100000 #NA pg/kg 22 #NA
D 4 5500000 #NA pg/kg 45 #NA
D 4 30769 #NA pg/kg- 33 #NA
day
SD Test
Material
Dosing
Protocol
Single
gavage
dose,
aqueous
suspension
Single
gavage
dose,
aqueous
suspension
7-day
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil
Single
gavage dose
in com oil
7-day
gavage
dose, 50%
ethanol
Bioavailability
Metric
Liver
concentration
Liver
concentration
Liver
concentration
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Referent
Vehicle
Corn oil
Corn oil
50%
ethanol
HpCDD, heptachloro-p-dibenzodioxin; HpCDF, heptachloro-p-dibenzofuran; HxCDD, hexachloro-p-dibenzodioxin; HxCDF, hexachlorodibenzofurn; PeCDD, pentachloro-p-dibenzodioxin; PeCDF,
pentachloro-p-dibenzofuran; TCDD, tetrachloro-p-dibenzodioxin; TCDF, tetrachlorodibenzofurn; OCDD, octochloro-p-dibenzodioxin
Appendix B - RBA Data
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
1
2
3
4
5
6
7
8
9
Study Study
Code
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Species Test
Material
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
TM Congener Cl Dose
Code #
1 2,3,7,8- D 4 4.13
TCDD
1 1,2,3,7,8- D 5 17.8
PeCDD
1 1,2,3,4,7,8- D 6 25.1
HxCDD
1 1,2,3,6,7,8- D 6 51.8
HxCDD
1 1,2,3,7,8,9- D 6 43.7
HxCDD
1 1,2,3,4,6,7, D 7 291
8-HpCDD
1 OCDD D 8 348
1 2,3,7,8- F 4 162
TCDF
1 1,2,3,7,8- F 5 413
PeCDF
+/- SD Unit RBA +/-
#NA pg/kg- 2.0 #NA
day
#NA pg/kg- 31.7 #NA
day
#NA pg/kg- 23.6 #NA
day
#NA pg/kg- 21.1 #NA
day
#NA pg/kg- 19.7 #NA
day
#NA pg/kg- 24.3 #NA
day
#NA pg/kg- 39.8 #NA
day
#NA pg/kg- 24.1 #NA
day
#NA pg/kg- 22.8 #NA
day
SD Test
Material
Dosing
Protocol
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
Reference
Material
Dosing
Protocol
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
Bioavailability
Metric
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
Test
Material
Vehicle
Dou§
Dou§
Dou§
Dou§
Dou§
DOUE
C
Dou§
Dou§
Dou§
;ball
;ball
;ball
;ball
;ball
;ball
;ball
;ball
;ball
Reference
Vehicle
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Page B-2
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
10
11
12
13
14
15
16
17
18
Study Study
Code
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Wittsiepeet WI07
al. 2007
Budinskyet BU08
al. 2008
Species Test
Material
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Sludge-
treated
soil
Swine Urban
soil
TM Congener Cl Dose
Code #
1 2,3,4,7,8- F 5 202
PeCDF
1 1,2,3,4,7,8- F 6 971
HxCDF
1 1,2,3,6,7,8- F 6 736
HxCDF
1 2,3,4,6,7,8- F 6 146
HxCDF
1 1,2,3,7,8,9- F 6 146
HxCDF
1 1,2,3,4,6,7, F 7 3559
8-HpCDF
1 1,2,3,4,7,8, F 7 1375
9-HpCDF
1 OCDF F 8 9706
1 2,3,7,8- D 4 70
TCDD
+/- SD Unit RBA +/-
#NA pg/kg- 34.4 #NA
day
#NA pg/kg- 40.9 #NA
day
#NA pg/kg- 31.5 #NA
day
#NA pg/kg- 39.4 #NA
day
#NA pg/kg- 28.6 #NA
day
#NA pg/kg- 28.5 #NA
day
#NA pg/kg- 28.0 #NA
day
#NA pg/kg- 42.2 #NA
day
2.0 SD pg/kg- 18 8
day
SD Test
Material
Dosing
Protocol
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
28-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
Reference
Material
Dosing
Protocol
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
28-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
Bioavailability
Metric
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
adipose+blood
+brain+liver+
muscle burden
Liver +
adipose burden
Liver +
adipose burden
(ND=l/2 DL)
Test
Material
Vehicle
Dou§
DOUE
C
Dou§
Dou§
Dou§
DOUE
C
DOUE
C
Dou§
Dou§
;ball
;ball
;ball
;ball
;ball
;ball
;ball
;ball
;ball
Reference
Vehicle
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Hexane/
acetone
Corn oil/
acetone
(99:1)
Page B-3
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
19
20
21
22
23
24
25
26
27
Study Study
Code
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Species Test
Material
Swine Urban
soil
Swine Urban
soil
Swine Urban
soil
Swine Urban
soil
Swine Flood-
plain soil
Swine Flood-
plain soil
Swine Flood-
plain soil
Swine Flood-
plain soil
Swine Flood-
plain soil
TM Congener Cl Dose
Code #
1 1,2,3,7,8- D 5 36
PeCDD
1 1,2,3,6,7,8- D 6 39
HxCDD
1 1,2,3,4,6,7, D 7 621
8-HpCDD
1 2,3,4,7,8- F 5 19
PeCDF
2 2,3,7,8- F 4 1120
TCDF
2 1,2,3,7,8- F 5 561
PeCDF
2 2,3,4,7,8- F 5 460
PeCDF
2 1,2,3,4,7,8- F 6 375
HxCDF
2 1,2,3,6,7,8- F 6 85
HxCDF
+/- SD
1.0 SD
1.0 SD
21 SD
1.0 SD
45 SD
23 SD
18 SD
15 SD
3.0 SD
Unit RBA +/-
pg/kg- 24 10
day
pg/kg- 38 21
day
pg/kg- 55 13
day
pg/kg- 32 9
day
pg/kg- 22 4
day
pg/kg- 30 13
day
pg/kg- 27 2
day
pg/kg- 35 2
day
pg/kg- 37 2
day
SD Test
Material
Dosing
Protocol
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
SD 30-day
repeated
dosing in
doughball
Reference
Material
Dosing
Protocol
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
30-day
repeated
dosing in
spiked
doughball
Bioavailability
Metric
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Test
Material
Vehicle
Dou§
Dou§
Dou§
Dou§
Dou§
Dou§
Dou§
Dou§
Dou§
;ball
;ball
;ball
;ball
;ball
;ball
;ball
;ball
;ball
Reference
Vehicle
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Page B-4
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
28
29
30
31
32
33
34
35
36
Study Study
Code
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Budinskyet BU08
al. 2008
Species Test
Material
Rat Urban
soil
Rat Urban
soil
Rat Urban
soil
Rat Urban
soil
Rat Urban
soil
Rat Flood-
plain soil
Rat Flood-
plain soil
Rat Flood-
plain soil
Rat Flood-
plain soil
TM Congener Cl Dose
Code #
1 2,3,7,8- D 4 302
TCDD
1 1,2,3,7,8- D 5 172
PeCDD
1 1,2,3,6,7,8- D 6 247
HxCDD
1 1,2,3,4,6,7, D 7 4820
8-HpCDD
1 2,3,4,7,8- F 5 100
PeCDF
2 2,3,7,8- F 4 6430
TCDF
2 1,2,3,7,8- F 5 3920
PeCDF
2 2,3,4,7,8- F 5 3370
PeCDF
2 1,2,3,4,7,8- F 6 2630
HxCDF
+/- SD Unit RBA +/-
17 SD pg/kg- 35 4
day
10 SD pg/kg- 40 3
day
14 SD pg/kg- 47 3
day
270 SD pg/kg- 34 2
day
6.0 SD pg/kg- 40 2
day
370 SD pg/kg- 89 12
day
230 SD pg/kg- 58 5
day
200 SD pg/kg- 52 3
day
150 SD pg/kg- 57 3
day
SD Test
Material
Dosing
Protocol
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
SD 30-day
repeated
exposure in
feed
Reference
Material
Dosing
Protocol
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
30-day
gavage in
corn
oil/acetone
(99:1)
Bioavailability
Metric
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Liver +
adipose burden
(ND=l/2 DL)
Test
Material
Vehicle
Feed
Feed
Feed
Feed
Feed
Feed
Feed
Feed
Feed
Reference
Vehicle
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Corn oil/
acetone
(99:1)
Page B-5
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
37
38
39
40
41
42
43
44
45
Study Study
Code
Budinskyet BU08
al. 2008
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Flood-
plain soil
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
TM Congener Cl Dose
Code #
2 1,2,3,6,7,8- F 6 649
HxCDF
1 2,3,7,8- D 4 32.8
TCDD
1 1,2,3,7,8- D 5 350
PeCDD
1 1,2,3,4,7,8- D 6 330
HxCDD
1 1,2,3,6,7,8- D 6 1070
HxCDD
1 1,2,3,7,8,9- D 6 1184
HxCDD
1 1,2,3,4,6,7, D 7 756
8-HpCDD
1 OCDD D 8 20200
1 2,3,7,8- F 4 2560
TCDF
+/- SD Unit RBA +/-
38 SD pg/kg- 56 4
day
#NA pg/kg- #NA #NA
day
#NA pg/kg- #NA #NA
day
#NA pg/kg #NA #NA
#NA pg/kg 22 5
#NA pg/kg #NA #NA
#NA pg/kg #NA #NA
#NA pg/kg #NA #NA
#NA pg/kg 27 5
SD Test
Material
Dosing
Protocol
SD 30-day
repeated
exposure in
feed
Single
gavage
dose,
aqueous
suspension
Single
gavage
dose,
aqueous
suspension
Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
Single
gavage
dose,
aqueous
suspension
Single
gavage
dose,
aqueous
suspension
Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
30-day
gavage in
corn
oil/acetone
(99:1)
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver +
adipose burden
(ND=l/2 DL)
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Feed
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil/
acetone
(99:1)
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-6
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
46
47
48
49
50
51
52
53
54
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
Rat Surface
soil 1
TM Congener Cl Dose +/- SD Unit RBA +/-
Code #
1 1,2,3,7,8- F 5 22000 #NA pg/kg 26 6
PeCDF
1 2,3,4,7,8- F 5 11260 #NA pg/kg 18 4
PeCDF
1 1,2,3,4,7,8- F 6 66400 #NA pg/kg 23 5
HxCDF
1 1,2,3,6,7,8- F 6 57000 #NA pg/kg 22 5
HxCDF
1 1,2,3,7,8,9- F 6 27200 #NA pg/kg 5 1
HxCDF
1 2,3,4,6,7,8- F 6 24600 #NA pg/kg 10 2
HxCDF
1 1,2,3,4,6,7, F 7 458000 #NA pg/kg 13 3
8-HpCDF
1 1,2,3,4,7,8, F 7 166600 #NA pg/kg 14 3
9-HpCDF
1 OCDF F 8 4140000 #NA pg/kg 10 3
SD Test
Material
Dosing
Protocol
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
SD Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-7
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DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
55
56
57
58
59
60
61
62
63
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
TM
Code
2
2
2
2
2
2
2
2
2
Congener Cl Dose
#
2,3,7,8- D 4 346
TCDD
1,2,3,7,8- D 5 1480
PeCDD
1,2,3,4,7,8- D 6 1258
HxCDD
1,2,3,6,7,8- D 6 2900
HxCDD
1,2,3,7,8,9- D 6 3120
HxCDD
1,2,3,4,6,7, D 7 2120
8-HpCDD
OCDD D 8 60400
2,3,7,8- F 4 28600
TCDF
1,2,3,7,8- F 5 80600
PeCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 100 10 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 74 6 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 67 6 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 46 4 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 32 4 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 23 3 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 76 9 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 89 9 SD Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-8
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
64
65
66
67
68
69
70
71
72
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 2
Rat Surface
soil 3
TM
Code
2
2
2
2
2
2
2
2
3
Congener Cl Dose +/- SD Unit
#
2,3,4,7,8- F 5 47200 #NA pg/kg
PeCDF
1,2,3,4,7,8- F 6 198000 #NA pg/kg
HxCDF
1,2,3,6,7,8- F 6 168600 #NA pg/kg
HxCDF
1,2,3,7,8,9- F 6 80000 #NA pg/kg
HxCDF
2,3,4,6,7,8- F 6 76800 #NA pg/kg
HxCDF
1,2,3,4,6,7, F 7 994000 #NA pg/kg
8-HpCDF
1,2,3,4,7,8, F 7 394000 #NA pg/kg
9-HpCDF
OCDF F 8 6500000 #NA pg/kg
2,3,7,8- D 4 418 #NA pg/kg
TCDD
RBA +/- SD Test
Material
Dosing
Protocol
50 4 SD Single
gavage
dose,
aqueous
suspension
61 6 SD Single
gavage
dose,
aqueous
suspension
59 5 SD Single
gavage
dose,
aqueous
suspension
16 2 SD Single
gavage
dose,
aqueous
suspension
32 3 SD Single
gavage
dose,
aqueous
suspension
28 3 SD Single
gavage
dose,
aqueous
suspension
34 3 SD Single
gavage
dose,
aqueous
suspension
21 3 SD Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-9
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
73
74
75
76
77
78
79
80
81
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
TM
Code
3
3
3
3
3
3
3
3
3
Congener Cl Dose
#
1,2,3,7,8- D 5 1446
PeCDD
1,2,3,4,7,8- D 6 1116
HxCDD
1,2,3,6,7,8- D 6 2760
HxCDD
1,2,3,7,8,9- D 6 3000
HxCDD
1,2,3,4,6,7, D 7 1824
8-HpCDD
OCDD D 8 47400
2,3,7,8- F 4 36800
TCDF
1,2,3,7,8- F 5 75200
PeCDF
2,3,4,7,8- F 5 43600
PeCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg 79 12 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 52 10 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 46 7 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 32 5 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 20 4 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 75 7 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 69 8 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 44 6 SD Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-10
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
82
83
84
85
86
87
88
89
90
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 3
Rat Surface
soil 4
Rat Surface
soil 4
TM
Code
3
3
3
3
3
3
3
4
4
Congener Cl Dose +/- SD Unit
#
1,2,3,4,7,8- F 6 158200 #NA pg/kg
HxCDF
1,2,3,6,7,8- F 6 128200 #NA pg/kg
HxCDF
1,2,3,7,8,9- F 6 60000 #NA pg/kg
HxCDF
2,3,4,6,7,8- F 6 61800 #NA pg/kg
HxCDF
1,2,3,4,6,7, F 7 680000 #NA pg/kg
8-HpCDF
1,2,3,4,7,8, F 7 294000 #NA pg/kg
9-HpCDF
OCDF F 8 4160000 #NA pg/kg
2,3,7,8- D 4 19.54 #NA pg/kg
TCDD
1,2,3,7,8- D 5 76.2 #NA pg/kg
PeCDD
RBA +/- SD Test
Material
Dosing
Protocol
42 6 SD Single
gavage
dose,
aqueous
suspension
42 6 SD Single
gavage
dose,
aqueous
suspension
13 2 SD Single
gavage
dose,
aqueous
suspension
22 3 SD Single
gavage
dose,
aqueous
suspension
18 3 SD Single
gavage
dose,
aqueous
suspension
22 3 SD Single
gavage
dose,
aqueous
suspension
13 2 SD Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
PageB-11
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
91
92
93
94
95
96
97
98
99
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
TM
Code
4
4
4
4
4
4
4
4
4
Congener Cl Dose
#
1,2,3,4,7,8- D 6 66
HxCDD
1,2,3,6,7,8- D 6 226
HxCDD
1,2,3,7,8,9- D 6 260
HxCDD
1,2,3,4,6,7, D 7 151.4
8-HpCDD
OCDD D 8 5380
2,3,7,8- F 4 2060
TCDF
1,2,3,7,8- F 5 3860
PeCDF
2,3,4,7,8- F 5 2080
PeCDF
1,2,3,4,7,8- F 6 11340
HxCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 82 #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 81 10 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 74 9 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 52 8 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 63 8 SD Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-12
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
100
101
102
103
104
105
106
107
108
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 4
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
TM Congener Cl Dose +/- SD Unit
Code #
4 1,2,3,6,7,8- F 6 9340 #NA pg/kg
HxCDF
4 1,2,3,7,8,9- F 6 4400 #NA pg/kg
HxCDF
4 2,3,4,6,7,8- F 6 4200 #NA pg/kg
HxCDF
4 1,2,3,4,6,7, F 7 90600 #NA pg/kg
8-HpCDF
4 1,2,3,4,7,8, F 7 27600 #NA pg/kg
9-HpCDF
4 OCDF F 8 1253333 #NA pg/kg
5 2,3,7,8- D 4 #NA #NA pg/kg
TCDD
5 1,2,3,7,8- D 5 15.56 #NA pg/kg
PeCDD
5 1,2,3,4,7,8- D 6 13.6 #NA pg/kg
HxCDD
RBA +/- SD Test
Material
Dosing
Protocol
62 8 SD Single
gavage
dose,
aqueous
suspension
19 3 SD Single
gavage
dose,
aqueous
suspension
28 3 SD Single
gavage
dose,
aqueous
suspension
33 4 SD Single
gavage
dose,
aqueous
suspension
39 5 SD Single
gavage
dose,
aqueous
suspension
27 3 SD Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
#NA #NA Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-13
-------
DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
109
110
111
112
113
114
115
116
117
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Species Test
Material
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
TM
Code
5
5
5
5
5
5
5
5
5
Congener Cl Dose
#
1,2,3,6,7,8- D 6 40.6
HxCDD
1,2,3,7,8,9- D 6 44.8
HxCDD
1,2,3,4,6,7, D 7 23.6
8-HpCDD
OCDD D 8 840
2,3,7,8- F 4 338
TCDF
1,2,3,7,8- F 5 847
PeCDF
2,3,4,7,8- F 5 464
PeCDF
1,2,3,4,7,8- F 6 2360
HxCDF
1,2,3,6,7,8- F 6 2040
HxCDF
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 61 18 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 56 15 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 47 13 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 42 11 SD Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-14
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DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
118
119
120
121
122
123
124
125
126
Study Study
Code
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Finleyetal. FI09
2009
Shu et al. SH88
1988
Shu et al. SH88
1988
Shu et al. SH88
1988
Shu et al. SH88
1988
Species Test
Material
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil 5
Rat Surface
soil -
Times
Beach
Rat Surface
soil -
Times
Beach
Rat Surface
soil -
Times
Beach
Rat Surface
soil -
Times
Beach
TM
Code
5
5
5
5
5
1
1
1
1
Congener Cl Dose
#
1,2,3,7,8,9- F 6 968
HxCDF
2,3,4,6,7,8- F 6 830
HxCDF
1,2,3,4,6,7, F 7 14460
8-HpCDF
1,2,3,4,7,8, F 7 4680
9-HpCDF
OCDF F 8 105333
2,3,7,8- D 4 3200
TCDD
2,3,7,8- D 4 7000
TCDD
2,3,7,8- D 4 40000
TCDD
2,3,7,8- D 4 37000
TCDD
+/- SD Unit RBA +/- SD Test
Material
Dosing
Protocol
#NA pg/kg 23 #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg #NA #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 19 7 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 25 8 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 13 5 SD Single
gavage
dose,
aqueous
suspension
#NA pg/kg 57 #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 64 #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 49 #NA Single
gavage
dose,
aqueous
suspension
#NA pg/kg 56 #NA Single
gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil,
3 dose
levels
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Bioavailability
Metric
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Liver burden
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Corn oil
Page B-15
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DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
127
128
129
130
131
Study Study
Code
Shu et al. SH88
1988
Shu et al. SH88
1988
Lucieretal. LU86
1986
Lucieretal. LU86
1986
Bonaccorsi BO84
etal. 1984
Species Test
Material
Rat Surface
soil -
Times
Beach
Rat Surface
soil -
Times
Beach
Rat Surface
soil -
Minker
MO
Rat Surface
soil -
Minker
MO
Rabbit Surface
soil -
Sevaso
TM Congener
Code
1 2,3,7,8-
TCDD
1 2,3,7,8-
TCDD
1 2,3,7,8-
TCDD
1 2,3,7,8-
TCDD
1 2,3,7,8-
TCDD
Cl Dose +/- SD Unit RBA +/- SD Test
# Material
Dosing
Protocol
D 4 175000 #NA pg/kg 59 #NA Single
gavage
dose,
aqueous
suspension
D 4 1450000 #NA pg/kg 48 #NA Single
gavage
dose,
aqueous
suspension
D 4 1100000 #NA pg/kg 22 #NA Single
gavage
dose,
aqueous
suspension
D 4 5500000 #NA pg/kg 45 #NA Single
gavage
dose,
aqueous
suspension
D 4 30769 #NA pg/kg- 33 #NA 7-day
day gavage
dose,
aqueous
suspension
Reference
Material
Dosing
Protocol
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Single
gavage dose
in com oil
Single
gavage dose
in com oil
7-day
gavage
dose, 50%
ethanol
Bioavailability
Metric
Liver burden
Liver burden
Liver
concentration
Liver
concentration
Liver
concentration
Test
Material
Vehicle
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Aqueous
suspension
Reference
Vehicle
Corn oil
Corn oil
Corn oil
Corn oil
50%
ethanol
HpCDD, heptachloro-p-dibenzodioxin; HpCDF, heptachloro-p-dibenzofuran; HxCDD, hexachloro-p-dibenzodioxin; HxCDF, hexachlorodibenzofuran; PeCDD, pentachloro-p-dibenzodioxin; PeCDF,
pentachloro-p-dibenzofuran; TCDD, tetrachloro-p-dibenzodioxin; TCDF, tetrachlorodibenzofuran; OCDD, octochloro-p-dibenzodioxin
Page B-16
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DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
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DRAFT 8-Do Not Cite, Quote, or Distribute - DRAFT 8
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