SEPA
United States
Environmental Protection
Agency
EPA/690/R-19/002F | September 2019 | FINAL
Provisional Peer-Reviewed Toxicity Values for
p-a,a,a-Tetrachlorotoluene
(CASRN 5216-25-1)
U.S. EPA Office of Research and Development
Center for Public Health and Environmental Assessment
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A United States
Environmental Protection
LbI M * Agency
EPA/690/R-19/002F
September 2019
https://www.epa.gov/pprtv
Provisional Peer-Reviewed Toxicity Values for
p-a,a,a-T etrachlorotoluene
(CASRN 5216-25-1)
Center for Public Health and Environmental Assessment
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
ii
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AUTHORS, CONTRIBUTORS, AND REVIEWERS
CHEMICAL MANAGERS
Chris Cubbison, PhD
Center for Public Health and Environmental Assessment, Cincinnati, OH
Jeff Swart out
Center for Public Health and Environmental Assessment, Cincinnati, OH
CONTRIBUTORS
J. Phillip Kaiser, PhD, DABT
Center for Public Health and Environmental Assessment, Cincinnati, OH
Scott C. Wesselkamper, PhD
Center for Public Health and Environmental Assessment, Cincinnati, OH
DRAFT DOCUMENT PREPARED BY
SRC, Inc.
7502 Round Pond Road
North Syracuse, NY 13212
PRIMARY INTERNAL REVIEWERS
Q. Jay Zhao, PhD, DABT
Center for Public Health and Environmental Assessment, Cincinnati, OH
Paul G. Reinhart, PhD, DABT
Center for Public Health and Environmental Assessment, Research Triangle Park, NC
This document was externally peer reviewed under contract to:
Eastern Research Group, Inc.
110 Hartwell Avenue
Lexington, MA 02421-3136
Questions regarding the content of this PPRTV assessment should be directed to the U.S. EPA
Office of Research and Development's Center for Public Health and Environmental Assessment.
in
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TABLE OF CONTENTS
COMMONLY USED ABBREVIATIONS AND ACRONYMS v
BACKGROUND 1
DISCLAIMERS 1
QUESTIONS REGARDING PPRTVs 1
INTRODUCTION 2
REVIEW OF POTENTIALLY RELEVANT DATA (NONCANCER AND CANCER) 6
HUMAN STUDIES 12
ANIMAL STUDIES 12
Oral Exposures 12
Inhalation Exposures 17
OTHER DATA (SHORT-TERM TESTS, OTHER EXAMINATIONS) 21
Genotoxicity 21
Supporting Animal Studies 21
Metab oli sm/T oxi cokineti c Studi e s 21
Mode-of-Action/Mechanistic Studies 22
DERIVATION 01 PROVISIONAL VALUES 23
DERIVATION OF PROVISIONAL ORAL REFERENCE DOSES 23
DERIVATION OF INHALATION REFERENCE CONCENTRATIONS 24
CANCER WEIGHT-OF-EVIDENCE DESCRIPTOR 24
MODE-OF-ACTION DISCI SSION 25
DERIVATION OF PROVISIONAL CANCER POTENCY VALUES 25
Derivation of a Provisional Oral Slope Factor 25
APPENDIX A. SCREENING PROVISIONAL VALUES 27
APPENDIX B. DATA TABLES 40
APPENDIX C. BENCHMARK DOSE MODELING RESULTS 66
APPENDIX D. REFERENCES 157
iv
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COMMONLY USED ABBREVIATIONS AND ACRONYMS1
a2u-g
alpha 2u-globulin
LD50
median lethal dose
ACGM
American Conference of Governmental
LOAEL
lowest-observed-adverse-effect level
Industrial Hygienists
MN
micronuclei
AIC
Akaike's information criterion
MNPCE
micronucleated polychromatic
ALD
approximate lethal dosage
erythrocyte
ALT
alanine aminotransferase
MOA
mode of action
AR
androgen receptor
MTD
maximum tolerated dose
AST
aspartate aminotransferase
NAG
Y-acctyl-(}-D-glucosaminidasc
atm
atmosphere
NCI
National Cancer Institute
ATSDR
Agency for Toxic Substances and
NOAEL
no-observed-adverse-effect level
Disease Registry
NIP
National Toxicology Program
BMD
benchmark dose
NZW
New Zealand White (rabbit breed)
BMDL
benchmark dose lower confidence limit
OCT
ornithine carbamoyl transferase
BMDS
Benchmark Dose Software
ORD
Office of Research and Development
BMR
benchmark response
PBPK
physiologically based pharmacokinetic
BUN
blood urea nitrogen
PCNA
proliferating cell nuclear antigen
BW
body weight
PND
postnatal day
CA
chromosomal aberration
POD
point of departure
CAS
Chemical Abstracts Service
PODadj
duration-adjusted POD
CASRN
Chemical Abstracts Service registry
QSAR
quantitative structure-activity
number
relationship
CBI
covalent binding index
RBC
red blood cell
CHO
Chinese hamster ovary (cell line cells)
RDS
replicative DNA synthesis
CL
confidence limit
RfC
inhalation reference concentration
CNS
central nervous system
RID
oral reference dose
CPHEA
Center for Public Health and
RGDR
regional gas dose ratio
Environmental Assessment
RNA
ribonucleic acid
CPN
chronic progressive nephropathy
SAR
structure activity relationship
CYP450
cytochrome P450
SCE
sister chromatid exchange
DAF
dosimetric adjustment factor
SD
standard deviation
DEN
diethylnitrosamine
SDH
sorbitol dehydrogenase
DMSO
dimethylsulfoxide
SE
standard error
DNA
deoxyribonucleic acid
SGOT
serum glutamic oxaloacetic
EPA
Environmental Protection Agency
transaminase, also known as AST
ER
estrogen receptor
SGPT
serum glutamic pyruvic transaminase,
FDA
Food and Drug Administration
also known as ALT
FEVi
forced expiratory volume of 1 second
SSD
systemic scleroderma
GD
gestation day
TCA
trichloroacetic acid
GDH
glutamate dehydrogenase
TCE
trichloroethylene
GGT
y-glutamyl transferase
TWA
time-weighted average
GSH
glutathione
UF
uncertainty factor
GST
glutathione-S -transferase
UFa
interspecies uncertainty factor
Hb/g-A
animal blood-gas partition coefficient
UFC
composite uncertainty factor
Hb/g-H
human blood-gas partition coefficient
UFd
database uncertainty factor
HEC
human equivalent concentration
UFh
intraspecies uncertainty factor
HED
human equivalent dose
UFl
LOAEL-to-NOAEL uncertainty factor
i.p.
intraperitoneal
UFs
subchronic-to-chronic uncertainty factor
IRIS
Integrated Risk Information System
U.S.
United States of America
ivf
in vitro fertilization
WBC
white blood cell
LC50
median lethal concentration
Abbreviations and acronyms not listed on this page are defined upon first use in the PPRTV document.
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September 2019
PROVISIONAL PEER-REVIEWED TOXICITY VALUES FOR
/>-a,a,a-TETRACHLOROTOLUENE (CASRN 5216-25-1)
BACKGROUND
A Provisional Peer-Reviewed Toxicity Value (PPRTV) is defined as a toxicity value
derived for use in the Superfund Program. PPRTVs are derived after a review of the relevant
scientific literature using established Agency guidance on human health toxicity value
derivations. All PPRTV assessments receive internal review by at least two Center for Public
Health and Environment Assessment (CPHEA) scientists and an independent external peer
review by at least three scientific experts.
The purpose of this document is to provide support for the hazard and dose-response
assessment pertaining to chronic and subchronic exposures to substances of concern, to present
the major conclusions reached in the hazard identification and derivation of the PPRTVs, and to
characterize the overall confidence in these conclusions and toxicity values. It is not intended to
be a comprehensive treatise on the chemical or toxicological nature of this substance.
Currently available PPRTV assessments can be accessed on the U.S. Environmental
Protection Agency's (EPA's) PPRTV website at https://www.epa.gov/pprtv. PPRTV
assessments are eligible to be updated on a 5-year cycle to incorporate new data or
methodologies that might impact the toxicity values or characterization of potential for adverse
human-health effects and are revised as appropriate. Questions regarding nomination of
chemicals for update can be sent to the appropriate U.S. EPA Superfund and Technology Liaison
(https://www.epa.gov/research/fact-sheets-regional-science).
DISCLAIMERS
The PPRTV document provides toxicity values and information about the adverse effects
of the chemical and the evidence on which the value is based, including the strengths and
limitations of the data. All users are advised to review the information provided in this
document to ensure that the PPRTV used is appropriate for the types of exposures and
circumstances at the site in question and the risk management decision that would be supported
by the risk assessment.
Other U.S. EPA programs or external parties who may choose to use PPRTVs are
advised that Superfund resources will not generally be used to respond to challenges, if any, of
PPRTVs used in a context outside of the Superfund program.
This document has been reviewed in accordance with U.S. EPA policy and approved for
publication. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
QUESTIONS REGARDING PPRTVS
Questions regarding the content of this PPRTV assessment should be directed to the
U.S. EPA Office of Research and Development's (ORD's) CPHEA.
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INTRODUCTION
/>a,a,a-Tetrachlorotoluene (4-chlorobenzotrichloride), CASRN 5216-25-1, belongs to
the class of compounds known as ring-chlorinated chlorotoluenes. It is used as an intermediate
for pigments, pesticides, and pharmaceutical manufacture Clipper et al.. 2017; MAK-
Commission, 2012). p-a,a,a-Tetrachlorotoluene is listed on the U.S. EPA Toxic Substances
Control Act"s public inventory (U.S. EPA 2017) and is registered with Europe"sRegistration,
Evaluation, Authori sation, and Restriction of Chemicals (REACH) program (ECHA, 2018).
The empirical formula for/;-a,a,a-tetrachlorotoluene is C7H4CI4 (see Figure 1). Table 1
summarizes the physicochemical properties for/;-a, a,a-tetrachlorotoluene. Under aqueous
conditions, p-a,a,a-tetrachlorotoluene is expected to hydrolyze rapidly to form/;-chlorobenzoic
acid and hydrochloric acid, based on several nonguideline studies demonstrating that this
reaction occurs within minutes (MAK-Commission. 2012; ECB. 2007). Because of the
chemical's high rate of reactivity, only estimated values are available for physicochemical
properties ofp-a,a,a-tetrachlorotoluene that would be measured in water, including water
solubility, octanol-water partition coefficient (log Kow), Henry's law constant, and soil
adsorption coefficient (KoC). Other environmental fate pathways, such as biodegradation, are not
expected to be important removal pathways forp-a,a,a-tetrachlorotoluene.
p-a, a, a-T etrachlorotoluene is a liquid at room temperature (ECHA, 2018). In the atmosphere,
p-a,a,a-tetrachlorotoluene is expected to react with water vapor. Indirect photochemical
degradation is expected to be slow, with an estimated half-life of 43 days for the reaction with
hydroxyl radicals.
c
CI
Figure l./7-a,a,a-Tetrachlorotoluene Structure
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Table 1. Physicochemical Properties of/>-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Property (Unit)
Value
Physical state
Liquid3
Boiling point (°C)
245b
Melting point (°C)
5.82a
Density (g/cm3 at 20°C)
1.4463b
Vapor pressure (mm Hg at 20°C)
0.03a (converted from 0.04 millibar)
pH (unitless)
NV
pKa (unitless)
NV
Solubility in water (mg/L at 25 °C)
4 (estimated)0
Octanol-water partition constant (log K.,,,,,)
4.5 (estimated)0
Henry's law constant (atm-m3/mol at 20°C)
1.9 x 10 4 (estimated)0
Soil adsorption coefficient (KoC) (L/kg)
1,600 (estimated)0
Atmospheric OH rate constant (cm3/molecule-sec at 25 °C)
2.5 x 10 13 (estimated)0
Atmospheric half-life (d)
43 (estimated)0
Relative vapor density (air =1)
NV
Molecular weight (g/mol)
229.92a
Flash point (°C)
110—13 la
aECHA (2018).
bHavnes et al. (2013).
°U.S. EPA (2012c) (with user-entered input for boilins point
= 245°C).
NY = not available.
A summary of available toxicity values for/;-a,a,a-tetrachlorotoluene from U.S. EPA and
other agencies/organizations is provided in Table 2.
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Table 2. Summary of Available Toxicity Values for
/>-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Source (parameter)3' b
Value (applicability)
Notes
Reference
Noncancer
IRIS
NV
NA
U.S. EPA (2018a)
HEAST
NV
NA
U.S. EPA (2011a)
DWSHA
NV
NA
U.S. EPA (2012a)
ATSDR
NV
NA
ATSDR (2018)
IPCS
NV
NA
IPCS (2018)
CalFPA
NV
NA
CalEPA (2016);
CalEPA (2018a):
CalEPA (2018b)
OSHA
NV
NA
OSHA (2017a):
OSHA (2017b)
NIOSH
NV
NA
NIOSH (2016)
ACGIH
NV
NA
ACGIH (2018)
Cancer
IRIS
NV
NA
U.S. EPA (2018a)
HE A ST/HEED (OSF)
20 (nig/kg-d)-1
Based on adenocarcinoma in the lung,
in a study with oral exposure for
17.5 wk in mice
U.S. EPA (1987):
U.S. EPA (2011a)
HEED (WOE)
B2: probably carcinogenic to
humans
Based on sufficient evidence from
animal studies, and no data from
epidemiologic studies
U.S. EPA (1987)
CalEPA
Listed as causing cancer
under Proposition 65
NA
CalEPA (2011):
CalEPA (2018a):
CalEPA (2018b)
DWSHA
NV
NA
U.S. EPA (2012a)
NTP
NV
NA
NTP (2016)
IARC
NV
NA
IARC (2018)
ACGIH
NV
NA
ACGIH (2018)
aSources: ACGIH = American Conference of Governmental Industrial Hygienists; ATSDR = Agency for Toxic
Substances and Disease Registry; CalEPA = California Environmental Protection Agency; DWSHA = Drinking
Water Standards and Health Advisories; HEAST = Health Effects Assessment Summary Tables; HEED = Health
and Environmental Effects Document; IARC = International Agency for Research on Cancer; IPCS = International
Programme on Chemical Safety; IRIS = Integrated Risk Information System; NIOSH = National Institute for
Occupational Safety and Health; NTP = National Toxicology Program; OSHA = Occupational Safety and Health
Administration.
Parameters: OSF = oral slope factor; WOE = weight of evidence.
NA = not applicable; NY = not available.
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Non-date-limited literature searches were conducted in October 2017 and updated in
December 2018 for studies relevant to the derivation of provisional toxicity values for
/;-a,a,a-tetrachlorotoluene (CASRN 5216-25-1). Searches were conducted using U.S. EPA's
Health and Environmental Research Online (HERO) database of scientific literature. HERO
searches the following databases: PubMed, TOXLINE (including TSCATS1), and Web of
Science. The following databases were searched outside of HERO for health-related values:
American Conference of Governmental Industrial Hygienists (ACGIH), Agency for Toxic
Substances and Disease Registry (ATSDR), California Environmental Protection Agency
(CalEPA), Defense Technical Information Center (DTIC), European Centre for Ecotoxicology
and Toxicology of Chemicals (ECETOC), European Chemicals Agency (ECHA), U.S. EPA
Chemical Data Access Tool (CDAT), U.S. EPA ChemView, U.S. EPA Health Effects
Assessment Summary Tables (HEAST), U.S. EPA Integrated Risk Information System (IRIS),
U.S. EPA Office of Water (OW), International Agency for Research on Cancer (IARC), Japan
Existing Chemical Data Base (JECDB), National Institute for Occupational Safety and Health
(NIOSH), National Toxicology Program (NTP), Organisation for Economic Co-operation and
Development (OECD) Existing Chemicals Database, OECD Screening Information Data Set
(SIDS) High Production Volume Chemicals (HPV) via International Programme on Chemical
Safety (IPCS) INCHEM, Occupational Safety and Health Administration (OSHA), and World
Health Organization (WHO).
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REVIEW OF POTENTIALLY RELEVANT DATA
(NONCANCER AND CANCER)
Tables 3 A and 3B provide overviews of the relevant noncancer and cancer databases,
respectively, for p-a,a,a-tetrachl orotol uen e, and include all potentially relevant repeated
short-term-, subchronic-, and chronic-duration studies, as well as reproductive and
developmental toxicity studies. Principal studies are identified in bold. The phrase "statistical
significance," used throughout the document, indicates ap-value of < 0.05 unless otherwise
specified. The use of the terms "significant" or "significantly" by themselves denotes statistical
significance, unless otherwise qualified.
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Table 3A. Summary of Potentially Relevant Noncancer Data for />-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Category"
Number of Male/Female,
Strain Species, Study
Type, Study Duration,
Reported Doses
Dosimetryb
Critical Effects
NOAELb
LOAELb
Reference
(comments)
Notes0
Human
1. Oral (mg/kg-d)
ND
2. Inhalation (mg/m3)
ND
Animal
1. Oral (mg/kg-d)
Short-term
6 M/6 F, S-D, rat, gavage,
daily for 14 d
Reported doses: 0, 1.25,
12.5,25.0, 75.0, 150,
300 mg/kg-d
0, 1.25, 12.5,
25.0, 75.0, 150,
300
Significantly decreased absolute liver weight
in M. At higher doses in both M and F, body
weights and food intake were significantly
reduced, and clinical signs of toxicity were
observed; 100% of animals treated with
300 mg/kg-d died, with indications of
gastrointestinal toxicity.
NDr
25.0
Liao (1989b. 1989c)
(Lowest 2 doses
were tested in a
separate experiment
and not considered
forNOAEL/LOAEL
determinations due
to lack of a
concurrent control).
NPR
Subchronic
10 M/10 F, S-D, rat,
gavage, daily for 90 d
Reported doses: 0,1.25,
12.5,25.0 mg/kg-d
0,1.25,12.5,
25.0
Significant increase in the incidence of
tubular atrophy and aspermatogenesis in
the testes, decreased absolute and relative
testis weights, reduced lymphocyte and
leukocyte counts, and decreased body
weights in male rats (at the high dose, the
changes in males were more pronounced).
1.25
12.5
Liao (1989a. 1989c)
NPR, PS
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Table 3A. Summary of Potentially Relevant Noncancer Data for />-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Category"
Number of Male/Female,
Strain Species, Study
Type, Study Duration,
Reported Doses
Dosimetryb
Critical Effects
NOAELb
LOAELb
Reference
(comments)
Notes0
2. Inhalation (mg/m3)
Short-term
10 M/10 F, albino
(CR:WI BR), rat, whole
body, 6 hr/d, 5 d/wk,
30 d
Reported analytical
concentrations: 0,3.98,
18.9,94.5 mg/m3
HECet: 0,
0.142,0.675,
2.53 (M); 0,
0.107, 0.506,
2.03 (F)
HECib: 0,1.49,
6.75, 23.6 (M);
0, 0.995, 4.73,
20.3 (F)
HECer: 0,
0.711, 3.38,16.9
Significant increase in incidence of upper
respiratory lesions in F; other lesions
increased at the same analytical
concentration, but with higher HECs, were
upper respiratory lesions in M and lower
respiratory lesions in both sexes. At the
high analytical concentration in both sexes,
respiratory lesions were severe and other
effects were seen, including mortality;
clinical signs; decreases in food and water
intake, body and organ weights, and
lymphocyte counts; and increases in
incidence of degenerative lesions in the
testes, spleen, and thymus.
0.107
0.506
Rose et al. (1984)
NPR, PS
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Table 3A. Summary of Potentially Relevant Noncancer Data for />-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Category"
Number of Male/Female,
Strain Species, Study
Type, Study Duration,
Reported Doses
Dosimetryb
Critical Effects
NOAELb
LOAELb
Reference
(comments)
Notes0
Reproductive/
Developmental
25 F, CD (SD) BR, rat,
whole body, 6 hr/d,
GDs6-19
Reported analytical
concentrations: 0, 4.1,
10.4, 25.2 mg/m3
HECer: 0, 1.0,
2.60, 6.30
Maternal: No significant effects were
observed.
Fetal: Significant decrease in mean fetal
weight and increase in fetal incidence per
litter of unossified sternebrae.
Maternal:
6.30
Fetal: 2.60
Maternal:
NDr
Fetal: 6.30
Edwards et al.
(1985)
NPR
aDuration categories are defined as follows: Acute = exposure for <24 hours; short term = repeated exposure for 24 hours to <30 days; long term (subchronic) = repeated
exposure for >30 days <10% lifespan for humans (>30 days up to approximately 90 days in typically used laboratory animal species); and chronic = repeated exposure
for >10% lifespan for humans (>~90 days to 2 years in typically used laboratory animal species) (U.S. EPA. 20021.
bDosimetry: Doses are presented as ADDs (mg/kg-day) for oral noncancer effects and as HECs (mg/m3) for inhalation noncancer effects. HECs are calculated
differently for systemic (ER), TB, and ET respiratory effects. The HEC for ER effects is calculated by treating /:>-«. u.u-tctrachlorotolucnc as a Category 3 gas and using
the following equation from U.S. EPA (1994) methodology: HECer = exposure level (mg/m3) x (hours/day exposed ^ 24 hours) x (days/week exposed ^ 7 days) x ratio
of blood-gas partition coefficient (animal: human). Because blood-gas coefficients for this chemical are unknown, a default ratio of 1 was used. HEC values for ET and
TB regions are calculated by treating/'-a.a.a-tetrachlorotoluene as a Category 1 gas and using the following equation from U.S. EPA (1994): HEC = exposure level
(mg/m3) x (hours/day exposed ^ 24 hours) x (days/week exposed ^ 7 days) x RGDR, where RGDR is the regional gas dose ratio (animal:human). RGDR (ET) and
RGDR (TB) are calculated as per U.S. EPA (1994) using default human VE and human and animal respiratory tissue surface area values and animal Ve values calculated
using study (if available) or U.S. EPA (1988) reference body-weight values.
°Notes: NPR = not peer reviewed; PS = principal study.
ADD = adjusted daily dose; BMCL = benchmark concentration lower confidence limit; BMDL = benchmark dose lower confidence limit; ER = extrarespiratory;
ET = extrathoracic; F = female(s); GD = gestation day; HEC = human equivalent concentration; LOAEL = lowest-observed-adverse-effect level; M = male(s); ND = no
data; NDr = not determined; NOAEL = no-observed-adverse-effect level; RGDR = regional gas dose ratio; S-D = Sprague-Dawley; TB = tracheobronchial; Ve = minute
volume.
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Table 3B. Summary of Potentially Relevant Cancer Data for />-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Category
Number of Male/Female,
Strain, Species, Study Type,
Study Duration, Reported
Doses
Dosimetry3
Critical Effects
Reference
(comments)
Notesb
Human
1. Oral (mg/kg-d)
ND
2. Inhalation (mg/m3)
ND
Animal
1. Oral (mg/kg-d)
Carcinogenicity
30 F, ICR-SLC, mouse, gavage,
2 times/wk for 17.5 wk
Reported doses: 0,0.05,0.13,
0.32,0.8,2 juL/d; equivalent to
nominal doses of 0,3.2,8.4,21,
51,130 mg/kg administered
twice per wk, ADDs of 0,0.21,
0.54,1.3,3.3, or 8.2 mg/kg-d,
and HEDs of 0,0.028,0.072,
0.18,0.44, and 1.1 mg/kg-d
averaged over the 18-m study
duration (see study description
and footnotes on p. 15)
0, 0.028, 072, 0.18,
0.44,1.1
Significant increase in the incidence of lung
adenocarcinomas at >0.32 mg/kg-d (HED). At
higher doses, significant increases in the
incidences of multiple adenomas in the lung;
squamous cell carcinomas, carcinomas in situ,
and multiple papillomas in the forestomach;
malignant lymphomas; thymomas; and skin
squamous cell carcinomas.
Fukuda et al.
(1980):
Fukuda et al.
(1979)
NPR, PS;
published in
Japanese but
available in an
English translation.
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Table 3B. Summary of Potentially Relevant Cancer Data for />-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Number of Male/Female,
Strain, Species, Study Type,
Study Duration, Reported
Reference
Category
Doses
Dosimetry3
Critical Effects
(comments)
Notesb
2. Inhalation (mg/m3)
ND
'Dosimetry: Doses are presented as HEDs (mg/kg-day) for oral cancer effects. The HEDs are calculated using D AFs. as recommended by U.S. EPA (2011b):
HED = ADD (mg/kg-day) x DAF. The DAF is calculated as follows: DAF = (BWa ^ BWh)1'4, where DAF = dosimetric adjustment factor, BWa = animal body weight,
and BWh = human body weight, using study (if available) or U.S. EPA (1988) reference body-weight values for B Wa and the reference value of 70 kg for BWh.
bNotes: NPR = non-peer reviewed; PS = principal study.
ADD = adjusted daily dose; B W = body weight; DAF = dosimetric adjustment factor; F = female(s); HED = human equivalent dose; ND = no data.
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HUMAN STUDIES
No adequate human studies that assessed associations between exposure to
/;-a,a,a-tetrachlorotoluene and subsequent health effects have been identified.
ANIMAL STUDIES
Oral Exposures
Short-Term-Duration Studies
liao (1989b. 1989c)
In an unpublished, non-peer-revievved, 2-week range-finding study, Liao (1989b) and
Liao (1989c) investigated the potential effects of/>-a,a,a-tetrachlorotoluene in Sprague-Dawley
(S-D) rats (six males and six females/group). Rats were administered single daily doses of
/;-a,a,a-tetrachlorotoluene (purity not specified) at 0, 25.0, 75.0, 150, or 300 mg/kg-day by
gavage in corn oil for 14 consecutive days (Experiment 1). Two additional dose levels (1.25 and
12.5 mg/kg-day; Experiment 2) were tested for 2 weeks upon completion of Experiment 1,
without a concurrent control. All animals were observed for clinical signs at least once daily,
and mortality checks were done twice daily. Body weights were measured on Days 1, 8, and 15.
Food consumption was measured weekly beginning on Day 1. Necropsies were performed on all
animals (i.e., those found dead, as well as those sacrificed at the end of the study). Organ
weights were measured for the adrenals, kidneys, liver, testes, and ovaries. Cecum, colon,
duodenum, ear, ileum, jejunum, stomach, and gross lesion tissues were fixed in case microscopic
examination was desired. No statistical analysis was included in the study. Fisher's exact test
and unpaired ^-tests for comparison of two means were performed for this review.
All animals in the 300-mg/kg-day group died or were sacrificed moribund by Days 3-5;
3/3 moribund males and 4/6 females had tremors. One male and one female in the
150-mg/kg-day group died on Days 7 and 8, respectively. The causes of death were not
reported. No mortalities were noted in the other dose groups. An increase in postdosing
salivation was observed in males and females at doses >75.0 mg/kg-day. At doses
>150 mg/kg-day, both males and females exhibited statistically significant decreases in activity,
increased incidences of urine and fecal stains, dark material around the nose and mouth,
dehydration, rough coat, and unkempt appearances.
Following 2 weeks of exposure, statistically significant decreases in mean body weights
(-11 to -38%) were observed at >75.0 mg/kg-day in both males and females, compared with
controls (see Table B-l). Body-weight gains were significantly reduced at doses
>25.0 mg/kg-day in males after 1 and 2 weeks of exposure, and >75.0 mg/kg-day in females
after 1 week. Food intake was significantly reduced in a dose-related manner in males (23-46%)
in the 75.0- and 150-mg/kg-day dose groups after 1 and 2 weeks of exposure, and in females at
>75 mg/kg-day after 1 week and at 150 mg/kg-day after 2 weeks (see Table B-2). This may
have contributed to the reduced body weights observed in these groups.
There were apparent increases in body weight, body-weight gain, and food consumption
in the Experiment 2 dose groups (1.25- and 12.5-mg/kg-day groups). Because no concurrent
controls were included, statistical analysis was done using Experiment 1 controls. Although the
study authors indicated that control group animals in Experiment 1 were sufficient for
comparison, the reliability of these analyses is uncertain, as the animals for Experiment 2 were
from a different batch than those in Experiment 1, delivered 1 month later.
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After 2 weeks, the study authors reported a dose-related statistically significant reduction
in absolute liver weight (-11 to -23%) at >25 mg/kg-day in male rats (see Table B-3). At higher
doses tested, statistically significant changes were observed in males for absolute testes and
kidney weight and relative kidney weight. Directional changes in absolute and relative weights
of several organs, however, were inconsistent, and the study authors noted that organ weights
were likely impacted by changes in body weight (see Table B-3). For example, in
150-mg/kg-day males, there was a significant decrease in absolute liver weight of 23%
(compared with controls), but also a significant increase in relative liver weight of 25%. Body
weight was decreased 38% in that group. Only absolute and relative adrenal weights in both
males and females were consistently significantly increased, compared with controls, at
150 mg/kg-day. The study authors indicated uncertainty as to whether these changes were
related to treatment.
For animals that died during the study, gross necropsy revealed red foci in the stomachs
of 5/6 and 4/5 high-dose males and females, respectively, and in both animals that died at the
150-mg/kg-day dose. A smaller number of animals in the high-dose group exhibited pale
discoloration of the duodenum, ileum, and jejunum. The study authors suggested that these
findings indicate possible gastrointestinal toxicity. Hemorrhagic meningeal vessels in the brains
of 4/6 high-dose males and 5/5 high-dose females were also observed but thought by the
investigators to be due to death struggle, rather than a direct effect of the treatment. Other
findings in the moribund animals included urine stains on the coat of 100%) of dead males and
females, and lower incidences of soft adrenal glands, dark red discoloration of the lungs, and wet
matting around the nose and mouth. The only notable gross necropsy findings in animals that
survived until the scheduled sacrifice were small testes in 3/5 males and urine stains on the coat
of 3/5 males and 3/5 females in the 150-mg/kg-day group. No microscopic or histological
examinations were done.
The data from the 1.25- and 12.5-mg/kg-day dose groups were dropped from
consideration in determining no-observed-adverse-effect level (NOAEL) and
lowest-observed-adverse-effect level (LOAEL) values due to the lack of a concurrent control for
comparison. A short-term oral LOAEL of 25.0 mg/kg-day is identified for statistically and
biologically (>10%) significant reductions in absolute liver weight in male S-D rats exposed by
daily gavage top-a,a,a-tetrachlorotoluene for 14 days. At higher doses, body weights and food
intake were significantly reduced, and clinical signs of toxicity were observed, in both sexes;
100%) of animals treated with 300 mg/kg-day died, with indications of gastrointestinal toxicity.
The lowest dose evaluated with a concurrent control was the LOAEL of 25.0 mg/kg-day;
therefore, no NOAEL is identified.
Subchronic-Duration Studies
liao (1989a. 1989c)
In an unpublished, non-peer-reviewed study, Liao (1989a) and Liao (1989c) investigated
the potential toxicity ofp-a,a,a-tetrachlorotoluene in S-D rats (10/sex/group) administered single
daily doses ofp- a, a, a-tetrachl orotoluene (purity not specified) at 0, 1.25, 12.5, or
25.0 mg/kg-day by gavage in corn oil for 90 consecutive days. Doses were selected based on the
results of the oral range-finding study described in l.iao (1989b) and Liao (1989c) and discussed
above. Animals were observed at least once daily for clinical signs of toxicity. Initial body
weights were recorded on Day 1, then weekly, and at sacrifice. Food consumption was
determined weekly. Ophthalmological examinations were done on all animals prior to study
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initiation and near the conclusion of the study. Blood samples were collected from
five rats/sex/treatment group for hematological, and biochemical analyses 5 days prior to
initiation of the study and again at sacrifice. Necropsies were performed on all animals:
five males and five females per group on both study Days 91 and 92. Organ weights were
obtained for the adrenals, liver, kidneys, brain, testes, and ovaries, and >30 tissues were prepped
for microscopic examination. Histopathological analysis was done on all tissues collected from
control and high-dose group animals; the lungs, liver, kidneys, testes, and gross lesions were the
only organs analyzed in the mid- and low-dose groups. Statistical analysis was performed by the
study authors and used two-tailed tests with a minimum significance level of 5%. Continuous
data were analyzed by analysis of variance (ANOVA) and Dunnett's test.
No mortalities were reported. Clinical signs were limited to significant increases in
salivation and urine stain on the coat, postdosing, in both males and females at 25.0 mg/kg-day.
Body weight was statistically significantly reduced in males starting on Week 7 of the study in
the 25.0-mg/kg-day group, and Week 10 of the study at 12.5 mg/kg-day (see Table B-4).
Relative to controls, terminal body weights were significantly reduced by 11% at
12.5 mg/kg-day and 15% at 25.0 mg/kg-day. In females, there were sporadic statistically
significant decreases in body weights relative to controls for a few weeks in the middle of the
study in the 12.5- and 25.0-mg/kg-day groups, but the differences reached to 10% in the
12.5-mg/kg-day groups at the end of experiment. Unlike the range-finding study, no significant
food consumption differences were noted in either sex, suggesting that the reductions in body
weight in males were not due to decreased appetite.
Hematological analysis identified statistically significant reductions in leukocytes in
males at 12.5 and 25.0 mg/kg-day and in females at 25.0 mg/kg-day (see Table B-5). Blood
leukocyte profiles indicated that reduced lymphocyte cell counts were likely the primary source
of leukocyte reductions. Compared to controls, lymphocyte cell counts were significantly
reduced by 37 and 46% at 12.5 and 25.0 mg/kg-day, respectively, in males and by 49% at
25.0 mg/kg-day in females. Erythrocyte counts and hematocrit (Hct) (%) were slightly lower
than controls in high-dose males, but hemoglobin (Hb) levels were comparable to controls, and
no consistent changes were observed in females. Some statistically significant changes in
clinical chemistry were measured; these included increased total protein and sodium levels in
low-dose males; increased chloride levels in low- and mid-dose males; increased total protein,
albumin, calcium, and phosphorus levels in mid-dose females; and increased sodium and
chloride in low- and mid-dose females. The study authors did not consider any of these to be
meaningful changes. Ophthalmological examination revealed no treatment-related changes.
At necropsy, the testes were reported to be smaller and softer in males dosed with
12.5 mg/kg-day (7/10) and 25.0 mg/kg-day (9/10), compared with controls (0/10). There were
significant dose-related decreases in both absolute and relative testes weights at doses
>12.5 mg/kg-day; relative testes weights decreased by 28 and 56% in mid- and high-dose males,
respectively (see Table B-6). Other statistically significant organ-weight changes in males were
increases in relative brain weight (+18%), liver weight (+17%), and kidney weight (+25%) in the
high-dose group and increased relative kidney weight (+15%) in the mid-dose group
(see Table B-6). Absolute organ weights for brain, liver and kidney were not affected by
treatment (see Table B-6). Given the 15% reduction in male body weights at time of necropsy
and lack of change in absolute organ weights, the increases in relative organ weights for brain,
liver, and kidney are not considered to be biologically significant. In contrast to the 14-day
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range-finding study (Xiao. 1989b. c), no significant increases in adrenal weights were observed.
There were no significant organ-weight changes in females in any treatment group.
Histological analysis showed seminiferous tubular atrophy and aspermatogenesis of the
testes, with partial or complete loss of germ cells, and only few Sertoli cells remaining in 70% of
males at 12.5 mg/kg-day and in 100% of males at 25.0 mg/kg-day (see Table B-7). Most of
these incidences were of marked severity. Aspermia of the epididymis was considered by the
investigators to be secondary to the testicular aspermatogenesis. In females, microscopic
findings were limited to scattered foci of cellular alteration (4/10 compared with 0/10 in controls)
in the livers of high-dose animals; no other significant histological findings were observed.
ANOAEL of 1.25 mg/kg-day and a LOAEL of 12.5 mg/kg-day are identified for
decreased body weights, decreased leukocyte and lymphocyte counts, increased incidence of
testicular atrophy and aspermatogenesis, and decreased absolute and relative testis weights in
males orally exposed to/;-a,a,a-tetrachlorotoluene for 90 days.
Chronic-Duration/Carcinogenicity Studies
Fukuda et al. (1980); Fukuda et al (1979)
In an oral cancer study originally published in Japanese, but available in an English
translation, Fukuda et al. (1980) and Fukuda et al. (1979)2 investigated the potential
carcinogenicity of/;-a,a,a-tetrachlorotoluene (purity not reported) in female ICR-SLC mice
(30/group) treated with 0, 0.05, 0.13, 0.32, 0.8, or 2 |iL (nominal doses of 0, 3.2, 8.4, 21, 51, or
130 mg/kg)3 in 0.1 mL of sesame oil by gavage, twice per week for 17.5 weeks. The adjusted
daily doses (ADDs) are calculated to be 0, 0.21, 0.54, 1.3, 3.3, or 8.2 mg/kg-day by averaging
the nominal doses over the entire study duration of 18 months (the animals were observed for up
to 18 months following the initiation of the experiment).4 The study was published as a
conference proceedings report and does not appear to have undergone a formal peer-review
process. All dead, moribund, and remaining animals that survived to 18 months were necropsied
and examined for tumors. Details of the nature of histological analyses were not provided. The
timing of 50% mortalities in some dose groups were noted. The study did not include other
observations or measurements (e.g., clinical signs, body weights, organ weights, etc.); however,
the average age in months of animals that became affected after the treatment, as well as
cumulative incidences of select tumors by months, was recorded. No statistical analysis of the
data was provided in the study. Tumor incidence data were analyzed using Fisher's exact and
Cochran-Armitage chi-square (x2) trend tests for the purposes of this review.
2The peer-review status of this study is uncertain but assumed to be "non-peer-reviewed."
3Reported doses of 0, 0.05, 0.13, 0.32, 0.8, and 2 ^L/day were converted to 0, 3.2, 8.4, 21, 51, or 130 mg/kg per
treatment using the following formula: dose (mg/kg-day) = reported dose
(nL/day) ^ 1,000 |iL/mL x u-tctrachlorotolucnc density (1,446.3 mg/mL) body weight (kg). Measured body
weights were not provided in the study. A reference body weight of 0.0225 kg was used for female mice in a
subchronic-duration study [in the absence of reference body weights for ICR-SLC mice, the average of values for
B6C3Fi and BAFi mice from U.S. EPA (1988) was used].
4The ADDs of 0, 0.2060, 0.5357, 1.319, 3.296, and 8.241 mg/kg-day were calculated by multiplying the nominal
doses in mg/kg by 2/7 days and 17.5/78 weeks, and to HEDs of 0, 0.028, 0.072, 0.18, 0.44, and 1.1 mg/kg-day
(calculated by multiplying the ADD x DAF, where DAF = [B Wa BWJ14 = 0.134, using a reference body weight
of 70 kg for humans).
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The study authors reported that the highest dose group reached 50% mortality by
4.7 months of age, while 50% of the animals dosed with 51 mg/kg died by 12.3 months of age.
Mortality in the other dose groups did not reach 50% prior to scheduled sacrifice at 18 months.
Statistically significant increases in the incidences of benign, malignant, and total tumors
were observed at doses >8.4 mg/kg, compared with controls (see Table B-8). Tumors that
occurred with the highest incidence were adenocarcinoma and adenoma in the lung, squamous
cell carcinoma in the forestomach, malignant lymphoma, thymoma, and squamous cell
carcinoma in the skin.
In general, tumors developed earlier in animals exposed to the highest dose compared
with the other treatment groups; the average ages of affected animals were 6.2 months in the
highest dose group, 14.8 months at 51 mg/kg, and 16.9-17.9 months at the lower doses. The
earliest appearing tumors were malignant lymphoma and thymoma, which first appeared in the
highest-dose group at around 4 months and reached their maximum incidence of 45% at around
9 months, and forestomach carcinoma, which first appeared in the highest-dose group at around
5 months and reached its maximum incidence of 25% at around 10 months. In contrast, lung
adenocarcinomas were first seen in the highest-dose group at around 10 months and in the 5 land
21-mg/kg groups at 13-14 months.
Lung adenocarcinomas were observed in 0/26, 3/22, 7/28, 10/22, 15/29, and 2/29 mice at
0, 3.2, 8.4, 21, 51, and 130 mg/kg, respectively. Incidences were significantly increased relative
to controls in the 8.4-, 21-, and 51-mg/kg groups. The low incidence of lung adenocarcinomas in
the highest dose group was not discussed by the study authors, but likely reflects the relatively
late development of this tumor and the high early mortality in this group due to more quickly
developing tumors (malignant lymphoma, thymoma, forestomach carcinoma). Excluding the
highest dose, the incidence of lung adenocarcinomas followed a significant dose-related trend
(p < 0.005). The incidences of multiple adenomas in the lung were also significantly increased at
>21 mg/kg.
In the forestomach, incidences of squamous cell carcinomas and carcinomas in situ also
followed dose-related trends (p < 0.001). The incidences of squamous cell carcinomas were
statistically significant, reaching 21 and 24% of animals in the two highest treatment groups,
respectively. Multiple papillomas in the forestomach were observed in all treatment groups, and
incidences were statistically significant at 21 mg/kg, but with reduced incidence at the two
highest dose groups, resulting in a lack of dose-response trend with the two high doses included
(p = 0.83), or with the highest dose dropped (p = 0.40). The reduced incidence was not
discussed by the study authors and it is uncertain if early mortality was a factor; the reduced
incidence could possibly be a result of transformation of papillomas to carcinomas. Excluding
the two highest doses, the incidence of forestomach multiple papillomas followed a significant
dose-related trend (p = 0.0075). There were no cancers of the forestomach in controls. The
study authors described a few non-neoplastic observations, including marked keratinization of
the forestomach epithelium in groups "receiving higher doses" and atypical epithelia in the lower
dose groups.
Other tumors with significant dose-related trends included thymomas (observed in
4/29 mice at 51 mg/kg and 8/29 mice at 130 mg/kg), malignant lymphomas (observed in
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5/29 mice at 130 mg/kg), and squamous cell carcinomas in the skin (observed in 6/29 mice at
130 mg/kg).
Single incidences of mammary adenocarcinoma, ear canal squamous cell carcinoma,
ovary glanulosa cell tumor, glandular stomach carcinoma, spindle cell carcinoma and sebaceous
gland carcinoma in the skin, and two incidences of salivary gland adenocarcinomas were
observed in different treatment groups, but these cancers did not show dose dependence and
were not significantly increased compared with controls.
Reproductive and Developmental Studies
No oral-route reproductive or developmental studies on p-a, a, a-tetrach 1 orotol uene in
animals have been identified.
Inhalation Exposures
Short-Term-Duration Studies
Roseetal. (1984)
Toxicities in albino (CR:WI BR) rats resulting from exposure to
/j-a,a, a-tetrachl orotol uene vapors were reported in an unpublished, non-peer-reviewed study by
Rose et al. (1984). Albino rats (10/sex/group) were exposed top-a,a,a-tetrach 1 orotoluene (purity
not specified) at mean measured concentrations of 0, 3.98, 18.9, or 94.5 mg/m3 by inhalation, for
6 hours/day, 5 days/week, for a period of 30 days. Control animals were exposed to air-only
under the same experimental conditions. The method of exposure was specified to be
whole-body. All animals were observed twice daily for clinical signs. Body weights were
measured twice prior to the start of exposures, and then weekly; food consumption was measured
weekly, and water intake was recorded daily. Hematology, blood chemistry, and urinalysis were
performed on all rats before the start of exposure, and on five animals/sex/group on Day 24. At
sacrifice, brain, pituitary, heart, lungs, liver, spleen, thymus, uterus, kidneys, thyroids, adrenals,
and gonads were weighed, and >30 tissues were processed for microscopic examination from
5-6 animals/sex in the control and exposed groups. Bone marrow was extracted from the femurs
of five males and five females per group for myelography. Statistical analyses included
Bartlett's test for heterogeneity of variance, Kruskal-Wallis analysis of ranks, Fisher's exact test
to detect differences among treatment groups, and Mantel's test for identifying exposure-related
trends.
Three animals in the 94.5-mg/m3 group died during the study. One male was found dead
in the exposure chamber following exposure on Day 17. Another male and one female were
found dead just before scheduled necropsies; the causes of death were not discussed. Clinical
signs and behavioral changes were observed in animals in the 94.5-mg/m3 group. The signs
were consistent with those expected following exposure to an irritant atmosphere; they included
irregular breathing/gasping, sneezing, rubbing snout with forepaws, partial closing of eyes,
abnormal body posture, and increased fighting between cage mates. Individual rats in this group
exhibited brown discharge or red staining around the nose and/or eyes and fur loss around the
snout and jaws. The appearance and behaviors in other exposure groups were similar to control
rats.
Body weights were depressed relative to controls throughout the study in both males and
females exposed to 94.5 mg/m3 /;-a, a,a-t etrachl orotol uene (see Table B-9). Animals exposed at
this level lost weight over the 4 weeks of the study. The loss in body weight was accompanied
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by significant reductions in cumulative food and water consumption in these animals. There
were no effects on body weight, body-weight gain, or food or water intake in the lower exposure
groups.
Hematological analysis on Day 24, for animals exposed to 94.5 mg/m3, showed large,
statistically significant decreases in total white blood cells (WBCs) (39 and 61% decreases),
circulating lymphocytes (48 and 73% decreases), and total cells in bone marrow (50 and
69%) decreases) in males and females, respectively; eosinophils were reduced by 100%> in males
(see Table B-10). However, although not statistically significant, there was a 40% increase in
WBCs for males exposed to 18.9 mg/m3, but no corresponding increase for females. Males in
the 18.9- and 94.5-mg/m3 groups also showed statistically significant increases in red blood cell
(RBC) count, Hb, and Hct relative to controls. Serum chemistry changes included statistically
significant reductions in alanine aminotransferase (ALT), albumin, and albumin:globulin (A:G)
ratio relative to controls in male rats at >18.9 mg/m3, as well as statistically significant
reductions in aspartate aminotransferase (AST), calcium, and creatinine at 94.5 mg/m3. There
were no biologically significant changes in other blood chemistry values, including alkaline
phosphatase, lactate dehydrogenase, glucose, or total proteins. Females in the high-exposure
group had increased serum phosphorous, reduced serum cholesterol, and reduced levels of
protein in the urine relative to controls. The biological significance of these serum chemistry
changes is uncertain.
Large changes in absolute organ weights were reported for the gonads (—63%), spleen
(-60%>), liver (-42%) and thymus (—83%) in male rats and for the uterus (—60%) in female rats
at 94.5 mg/m3 (see Table B-l 1). Smaller weight changes were seen in other organs in
high-exposure group males and females, generally decreases in absolute organ weights and
increases in body weight-adjusted organ weights, which the study authors thought reflected the
large decreases in body weight in these groups.
Necropsy findings included high incidence of small testes (9/9) in males at 94.5 mg/m3
and small thymus in both males (8/9) and females (10/10) at this concentration (see Table B-12).
Other reported effects in the animals at 94.5 mg/m3 were minimal adipose tissue, alopecia, and
stained or badly groomed fur. There were no significant gross findings in animals from other
exposure groups.
Microscopic examination showed decreased cellularity in the red and white pulp of the
spleen, thymic involution in both males and females, and lesions in reproductive organs,
including tubular atrophy/a spermatogenesis in the testes of males and reduced endometrial width
in the uterus of females at 94.5 mg/m3 (see Table B-13). These organs were not examined for
histopathology in the mid- and low-exposure groups. No lesions in these tissues were seen in
controls.
Microscopic lesions were also found in the respiratory tract, including the nasal passages,
larynx, trachea, tracheal carina, and bronchiolar epithelium. Specific lesions and incidences are
listed in Table B-14 for the upper respiratory tract, and Table B-15 for the lower respiratory tract.
These lesions occurred primarily in the 18.9- and 94.5-mg/m3 groups for both males and females,
and incidence and/or severity of the lesions generally increased with exposure concentration.
For example, atrophy of the olfactory epithelium was focal in 1/5 and 3/5 males and 0/5 and
5/5 females at 3.98 and 18.9 mg/m3, respectively, and severe in 6/6 males and 5/5 females at
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94.5 mg/m3. Severe lesions, including severe atrophy of the olfactory epithelium in the nasal
passages, severe epithelial ulceration of the trachea and carina, and severe ulceration of the
bronchiolar epithelium occurred only in the 94.5-mg/m3 groups of both sexes. Lesions in the
18.9-mg/m3 males and females were generally characterized as minimal, moderate, or focal. The
location of the lesions within the nasal passages was not reported.
The respiratory lesions were the most sensitive endpoints in rats exposed to
/;-a,a,a-tetrachlorotoluene vapor for 30 days. Respiratory lesions were significantly increased at
>18.9 mg/m3 in both males and females, and some of these lesions (e.g., atrophy of the olfactory
epithelium in males and keratinizing epithelial hyperplasia in the larynx in females) also
occurred at low incidence at 3.98 mg/m3. The lesions showed a dose-response, with severe
lesions occurring only at the high concentration of 94.5 mg/m3. Microscopic lesions in other
tissues, such as decreased splenic cellularity, thymic involution, and testicular atrophy were also
seen at this concentration, as were gross depletion of the thymus and testes and decreases in
absolute weights of these and other organs, as well as associated changes such as decreased
lymphocytes, all likely affected by weight loss and malnutrition in these animals due to their low
food and water intake. Gross clinical signs of toxicity and mortality were also observed at this
concentration. The respiratory tract lesions identify a NOAEL of 3.98 mg/m3 and a LOAEL of
18.9 mg/m3 for male and female rats in this study, based on analytical concentrations.
The analytical concentrations of 3.98. 18.9, and 94.5 mg/m3 (6 hours/day, 5 days/week)
correspond to human equivalent concentrations (HECs) of 0.711, 3.38, and 16.9 mg/m3 for
systemic (extrarespiratory [ER]) effects (HECer); 0.142, 0.675, and 2.53 mg/m3 for males and
0.107, 0.506, and 2.03 mg/m3 for females for upper (extrathoracic [ET]) respiratory effects
(HECet); and 1.49, 6.75, and 23.6 mg/m3 for males and 0.995, 4.73, and 20.3 mg/m3 for females
for tracheobronchial [TB] respiratory effects (HECtb), using (U.S. EPA. 1994) methods.5
Considering the HEC conversions, the most sensitive effects in the study were upper respiratory
lesions, with a NOAEL (HECet) of 0.107 mg/m3 and a LOAEL (HECet) of 0.506 mg/m3 based
on female rats.
Subchronic-Duration Studies
No sub chronic-duration inhalation studies of/;-a,a,a-tetrachlorotoluene in animals were
identified.
5Measured exposure concentrations of 0, 3.98, 18.9, and 94.5 |ig/L 6 hours/day, 5 days/week were converted to
continuous concentrations of 0,0.711, 3.38, and 16.9 mg/m3 using the following equation: exposure concentration
(mg/m3) x hours/day (6 hours/24 hours) x days/week (5 days/7 days). />-a.a.a-Tctrach 1 oroto 1 ucnc has characteristics
of a highly reactive, Category 1 gas that often results in portal-of-entry effects in the ET and TB regions as well as
less reactive Category 3 gas for ER effects. As HEC equations for a Category 2 gas are currently unavailable, the
HECs are calculated using both Category 1 and Category 3 gas equations. The HECer for extrarespiratory effects
was calculated as per U.S. EPA (1994) by treating p-a.a.ct tetrachlorotoluene as a Category 3 gas and multiplying
the continuous concentration in mg/m3 x ratio of animal:human blood-gas partition coefficients (default value of 1
applied in the absence of experimental data). HEC values for ET and TB regions were calculated by treating
p-a,a,a-tetrachlorotoluene as a Category 1 gas and using the following equation from U.S. EPA (1994):
HEC = continuous concentration (mg/m3) x RGDR, where RGDR is the regional gas dose ratio (animal:human).
RGDR (ET) and RGDR (TB) were calculated as per U.S. EPA (1994) using default human minute volume (VE) and
human and animal respiratory tissue surface area values and animal VE values calculated from time-weighted
average body weights for each dose group in the study.
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Chronic-Duration/Carcinogenicity Studies
No chronic-duration studies or cancer bioassays on /;-a,a,a-tetrachlorotoluene by
inhalation exposure in animals were identified.
Reproductive and Developmental Studies
Edwards et al. (1985)
In an unpublished and non-peer-revievved study, Edwards et al. (1985) investigated the
potential effects of/;-a,a,a-tetrachlorotoluene vapor on pregnancy and in utero development in
CD (SD) BR strain rats. Mated female rats (25 per group) were exposed to mean measured
concentrations of 4.1, 10.4, or 25.2 mg/m3 for 6 hours/day on Gestation Days (GDs) 6-19.
Control animals were transferred to exposure chambers but exposed to air only. The method of
exposure was not specified but was clearly whole-body via examination of the exposure chamber
diagram. Examinations for clinical signs were performed twice daily. Water consumption was
measured daily; food consumption was measured between recordings of body weight. Body
weights of dams were measured on GDs 1,3,6, 10, 14, and 17, and at sacrifice on GD 20.
Pregnancy rates were recorded. After gross necropsy, ovaries and uteri were examined to
determine litter parameters, including number of corpora lutea, number and distribution of live
young, number and distribution of embryonic/fetal deaths, individual fetal weights, and fetal
abnormalities. Pre- and postimplantation losses were determined. Half of the pups in each litter
were examined for visceral abnormalities and the other half were examined for macroscopic and
skeletal abnormalities and variations. For statistical analysis on litter data and skeletal
deviations, the study authors performed Jonckheere and Kruskal-Wallis nonparametric tests and
used the litter as the basic sampling unit.
There were no mortalities or adverse clinical signs in treated dams. Water consumption
was not affected by treatment. Food consumption was reduced (6-14%) in the 25.2-mg/m3
group but was similar to controls in the two lower exposure groups. At 25.2 mg/m3, maternal
group mean body weights were significantly reduced beginning on GD 14 (-5%) and continuing
through sacrifice on GD 20 (-9%) (see Table B-16). Body-weight gain in this group was
significantly reduced by 27-35% relative to controls throughout the study. No significant
changes in body weight or body-weight gain were observed in the other exposure groups. There
were no treatment-related gross abnormalities in exposed dams. Treatment had no significant
effects on pregnancy rates, number of implants, or number of live young (see Table B-17).
Intergroup differences in postimplantation losses did not appear to be related to exposure.
Specifically, the percentage of postimplantation loss decreased with increased concentration and
was statistically significantly decreased compared to control at 25.2 mg/m3. Therefore, this
effect is not biologically relevant.
Mean fetal weights were statistically significantly reduced by 8% at 25.2 mg/m3, relative
to controls (see Table B-17). There were no significant effects on the incidences of
malformations, or visceral or skeletal anomalies. The only skeletal variation affected was a
significant increase in the incidence of fetuses with unossified sternebrae in the 25.2-mg/m3
exposure group (see Table B-l 8). The study authors suggested that the increase in unossified
sternebrae could be associated with the lower mean fetal weight observed at this concentration.
Based on unadjusted analytical concentrations, the maternal NOAEL is 25.2 mg/m3 based
on the lack of significant treatment-related effects. The fetal NOAEL and LOAEL are 10.4 and
25.2 mg/m3 for decreased mean fetal weight and increased incidence of unossified sternebrae.
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The analytical concentrations of 10.4 and 25.2 mg/m3 correspond to HECs (HECer)6 of 2.60 and
6.30 mg/m3.
OTHER DATA (SHORT-TERM TESTS, OTHER EXAMINATIONS)
Genotoxicity
No information has been located on the genotoxicity of/;-a,a,a-tetrachl orotoluene.
Supporting Animal Studies
A letter from Hooker Chemical Co (1981a) and Hooker Chemical Co (1981b) reported a
median lethal dose (LD50) (95% confidence interval [CI]) of 820 (730-910) mg/kg in rats orally
exposed to /;-a, a,a-tetrachl orotoluene. Symptoms described included tremors, decreased motor
activity, diarrhea, chromodacryorrhea, and piloerection. At necropsy, irritation to the
gastrointestinal tract was noted. The letter also noted that a rat LD50 of 805 mg/kg was listed in a
product data sheet issued by Ihara Chemical Industry Co., Ltd.
A dermal LD50 of >2,000 mg/kg was reported in rabbits (Hooker Chemical Co, 1981a, b).
There were no signs of toxicity or test-article-related gross tissue changes. Skin reactions were
described as mild to moderate. Although not corrosive, exposure caused skin erythema and
edema during testing. Skin reactions scored by the Draize method gave a primary skin irritation
value of 1.58. In the eye, /;-a,a,a-tetrachl orotoluene induced irritation to the conjunctival tissue,
but not the cornea or iris in rabbits.
Fukuda et al. (1980) mentioned a dermal carcinogenicity skin-painting study in mice by
Matsushita et al., which reportedly resulted in skin tumors, but no such study was found in the
literature.
Metabolism/Toxicokinetic Studies
The metabolism and excretion of p-a,a,a-tetrachlorotoluene were studied in female S-D
rats administered a single dose of 1.5 (two rats) or 102 (one rat) mg/kg of radiolabeled (14C)
/>-a,a,a-tetrachlorotoluene (98% purity) by gavage (Quistad ct al.. 1985). Immediately after
dosing, the animals were housed in glass metabolism chambers for collection of urine, feces, and
expired carbon dioxide (CO2); urine was collected daily. Metabolites were analyzed by
thin-layer chromatography and/or gas-liquid chromatography-mass spectrometry. The animals
were sacrificed 4-6 days after dosing, and select organs and tissues were dissected, weighed, and
used for quantification of 14C residues.
Following administration of radiolabeled (14C) p-a, a, a-tetrachl orotoluene, most of the
radiolabel was excreted in the urine (77-87%) and a smaller amount in the feces (9—14%), with
only 4% remaining in the carcass after 4-6 days, regardless of dose, p-a,a,a-Tetrachlorotoluene
was primarily hydrolyzed top-chlorobenzoic acid, which was excreted in urine as
/>-chlorohippuric acid. a,a',4,4'-Tetrachlorostilbene was identified as a metabolite in feces.
6Analytical concentrations of 0, 4.1, 10.4, and 25.2 mg/m3 administered 6 hours/day on GDs 6-19 were converted to
continuous concentrations of 0, 1.0, 2.60, and 6.30 mg/m3 using the following equation: reported concentration
(mg/m3) x hours/day (6 hours/24 hours) x days/week (7 days/7 days). HECer values of 0, 1.0, 2.60, and 6.30 mg/m3
were calculated by treating p-a.a.a-tctrachlorotolucne as a Category 3 gas and using the following equation from
U.S. EPA (1994) methodology: HECer = continuous concentration (mg/m3) x ratio of blood-gas partition
coefficients animal:human. Because blood-gas coefficients for this chemical are unknown, a default ratio of 1 was
used.
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There was no evidence of any selective concentration of 14C residues in any tissues, although
some deposition in fat was detected in the animal dosed with 102 mg/kg.
Mode-of-Action/Mechanistic Studies
No information has been located.
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DERIVATION OF PROVISIONAL VALUES
Tables 4 and 5 present summaries of noncancer and cancer references values,
respectively, for /;-a,a,a-tetrachlorotoluene.
Table 4. Summary of Noncancer Reference Values for
/>-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Toxicity Type
(units)
Species/
Sex
Critical Effect
p-Reference
Value
POD
Method
POD
(HED/HEC)
UFc
Principal
Study
Screening
subchronic p-RfD
(mg/kg-d)
Rat/M
Tubular atrophy and
aspermatogenesis in
testes
6 x 1(T4
BMDLio
0.167
300
Liao (1989a.
1989c)
Screening
chronic p-RfD
(mg/kg-d)
Rat/M
Tubular atrophy and
aspermatogenesis in
testes
6 x 1(T5
BMDLio
0.167
3,000
Liao (1989a.
1989c)
Screening
subchronic p-RfC
(mg/m3)
Rat/M
Atrophy of the olfactory
epithelium
5 x 1(T5
BMCLio
0.0141
300
Rose et al.
(1984)
Chronic p-RfC
(mg/m3)
NDr
BMCL = 95% lower confidence limit on the benchmark concentration (subscripts denote benchmark response:
i.e., 10 = concentration associated with 10% extra risk); BMDL = 95% lower confidence limit on the benchmark
dose; HEC = human equivalent concentration; HED = human equivalent dose; M = male(s); NDr = not determined;
POD = point of departure; p-RfC = provisional reference concentration; p-RfD = provisional reference dose;
UFC = composite uncertainty factor.
Table 5. Summary of Cancer Reference Values for
/>-a,a,a-Tetrachlorotoluene (CASRN 5216-25-1)
Toxicity Type
(units)
Species/
Sex
Tumor Type(s)
Cancer
Value
Principal
Study
Screening p-OSF
(mg/kg-d)"1
Mouse/F
Adenocarcinomas and multiple adenomas in the
lungs, thymomas, malignant lymphomas, multiple
papillomas, squamous cell carcinomas and
carcinomas in situ in the forestomach, and squamous
cell carcinomas in the skin
1.6 x 101
Fukuda et al.
(1980);
Fukuda et al.
(1979)
p-IUR (mg/m3)-1
NDr
F = female(s); NDr = not determined; p-IUR = provisional inhalation unit risk; p-OSF = provisional oral slope
factor.
DERIVATION OF PROVISIONAL ORAL REFERENCE DOSES
No data have been located on the effects of oral exposure to p-a,a,a-tetrachl orotoluene in
humans. Information on the toxicity of repeated oral exposure to /;-a,a,a-tetrachl orotol uene is
limited to an unpublished, non-peer-revievved, 90-day gavage study in rats (l.iao. 1989a. c) that
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was preceded by an unpublished 14-day range-finding study by the same investigators (I.iao.
1989b. c). There is also a translated version of a publication originally reported in Japanese that
describes a study in which mice were treated for 17.5 weeks by gavage and monitored for tumor
development up to 18 months of age, but it did not report on any non-neoplastic endpoints
(Fukuda et al, 1980, 1979). None of these studies were suitable for the use in deriving
provisional noncancer toxicity values, either because they were unpublished and not peer
reviewed, or because they did not provide suitable data. Although it could not be used to
develop provisional toxicity values, the unpublished 90-day study by Liao (1989a) and l.iao
(1989c) was well conducted and reported adequate information with which to derive
screening-level provisional reference doses (p-RfDs) for /;-a,a,a-tetrachlorotoluene
(see Appendix A).
DERIVATION OF INHALATION REFERENCE CONCENTRATIONS
Studies on the inhalation toxicity of/;-a,a,a-tetrachlorotoluene vapors are limited to a
30-day study of systemic toxicity in rats and a developmental toxicity study in rats, neither of
which was published or peer reviewed. For this reason, both studies were considered inadequate
to derive provisional reference concentrations (p-RfCs). The studies did, however, provide
adequate information with which to derive a screening-level subchronic p-RfC for
/;-a,a,a-tetrachlorotoluene (see Appendix A).
CANCER WEIGHT-OF-EVIDENCE DESCRIPTOR
Following U.S. EPA (2005) Guidelines for Carcinogen Risk Assessment,
/;-a,a,a-tetrachlorotoluene is "Likely to Be Carcinogenic to Humans" by oral exposure
(see Table 6). Although there are no human studies to indicate cancer risk, a single oral cancer
study in mice (Fukuda et al, 1980, 1979) included multiple dose levels but was limited by
testing of a single sex, dosing only twice a week, a short exposure period of 17.5 weeks, a
less-than-lifetime observation period of 18 months, relatively small group sizes of 26-31 mice,
and marginally adequate reporting of methods and results. However, this study distinctly
showed that after a relatively short duration of exposure (17.5 weeks) to
/>-a,a,a-tetrachlorotoluene, tumors formed at multiple sites, developed quickly, had a high
proportion of malignancy, and displayed dose-related increases.
There is "Inadequate Information to Assess Carcinogenic Potential" of
/;-a,a,a-tetrachlorotoluene by inhalation exposure. No suitable human or animal data are
available by this route (see Table 6).
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Table 6. Cancer WOE Descriptor for/>-a,a,a-Tetrachlorotoluene
Possible WOE Descriptor
Designation
Route of Entry
(oral, inhalation, or
both)
Comments
"Carcinogenic to Humans"
NS
NA
No human data are available.
"Likely to Be Carcinogenic
to Humans"
Selected
Oral
A single oral cancer bioassay in animals was
located. The study found dose-related
increases in lung adenocarcinomas and
adenomas, as well as cancers of the
forestomach, skin, and lymphatic organs in
female mice exposed to
/7-a,a,a-tetrachlorotoluene for 17.5 wk and
observed form) to 18 mo (Fukuda et al.,
1980.1979).
"Suggestive Evidence of
Carcinogenic Potential"
NS
NA
Evidence of the carcinogenic potential of
u.u-tctrachlorotolucnc supports a stronger
descriptor by oral exposure, and there are no
data available to support this descriptor by
inhalation exposure.
"Inadequate Information to
Assess Carcinogenic
Potential"
Selected
Inhalation
This descriptor is selected due to the lack of
any information on the carcinogenicity of
p-a,«,«-tetrach 1 o roto 1 u ene by inhalation
exposure.
"Not Likely to Be
Carcinogenic to Humans "
NS
NA
The available data do not support this
descriptor.
NA = not applicable; NS = not selected; WOE = weight of evidence.
MODE-OF-ACTION DISCUSSION
The Guidelines for Carcinogenic Risk Assessment (U.S. EPA. 2005) define mode of
action (MO A)".. .as a sequence of key events and processes, starting with interaction of an agent
with a cell, proceeding through operational and anatomical changes, and resulting in cancer
formation." Examples of possible modes of carcinogenic action for any given chemical include
"mutagenicity, mitogenesis, programmed cell death, cytotoxicity with reparative cell
proliferation, and immune suppression."
Although/;-a,a,a-tetrachlorotoluene has been classified as "Likely to Be Carcinogenic to
Humans, " there are no data available to support a hypothesis of a MO A, including the absence of
any genotoxic or mechanistic studies. Therefore, a detailed MOA discussion for
/}-a,a,a-tetrachlorotoluene is precluded.
DERIVATION OF PROVISIONAL CANCER POTENCY VALUES
Derivation of a Provisional Oral Slope Factor
No data have been located on the carcinogenic effects of exposure to
/}-a,a,a-tetrachlorotoluene in humans. The only information on the carcinogenicity of repeated
oral exposure to/>-a,a, a-t etrachlorotoluene is from Fukuda et al. (1980). who reported significant
dose-related trends for increased incidence of multiple tumor types in female mice exposed to
/;-a,a,a-tetrachlorotoluene by gavage for 17.5 weeks and observed for up to 18 months, including
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adenocarcinomas and multiple adenomas in the lungs, thymomas, malignant lymphomas,
multiple papillomas, squamous cell carcinomas and carcinomas in situ in the forestomach, and
squamous cell carcinomas in the skin (see Tables A-8 and B-8). Because the 17.5-week study
duration was less than lifetime for mice (2 years), a less-than-lifetime adjustment factor is
generally applied to the oral slope factor (OSF) (U.S. EPA. 1980). However, a provisional oral
slope factor (p-OSF) is not derived here because the Fukuda et al. (1980) study did not undergo a
formal peer-review process. In addition, the study duration was much less than lifetime,
requiring the application of an adjustment factor to account for the expected increase in the
tumor incidence rate with increasing age (U.S. HP A. 1980). with attendant increased uncertainty.
A screening p-OSF, which may be useful for some applications, is derived in Appendix A.
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APPENDIX A. SCREENING PROVISIONAL VALUES
For reasons noted in the main Provisional Peer-Reviewed Toxicity Value (PPRTV)
document, it is inappropriate to derive provisional reference doses (p-RfDs), provisional
reference concentrations (p-RfCs), or a provisional oral slope factor (p-OSF) for
/;-a,a,a-tetrachlorotoluene. However, information is available for this chemical, which although
insufficient to support derivation of a provisional toxicity value under current guidelines, may be
of limited use to risk assessors. In such cases, the Center for Public Health and Environmental
Assessment (CPHEA) summarizes available information in an appendix and develops a
"screening value." Appendices receive the same level of internal and external scientific peer
review as the main documents to ensure their appropriateness within the limitations detailed in
the document. Users of screening toxicity values in an appendix to a PPRTV assessment should
understand that there is considerably more uncertainty associated with the derivation of an
appendix screening toxicity value than for a value presented in the body of the assessment.
Questions or concerns about the appropriate use of screening values should be directed to the
CPHEA.
DERIVATION OF SCREENING PRO VISIONAL ORAL REFERENCE DOSES
As discussed in the main body of this PPRTV assessment, the 90-day study by l.iao
(1989a) and Liao (1989c) could not be used to derive provisional reference values because it has
not been peer reviewed. The study did, however, appear to be adequately designed and
conducted, and it provided dose-response information on a wide range of endpoints suitable for
use in quantitative toxicity assessment. To account for the uncertainty associated with basing a
toxicity assessment on an unpublished study that has not been peer reviewed, the assessment is
considered a screening-level assessment.
A no-observed-adverse-effect level (NOAEL) of 1.25 mg/kg-day and a
lowest-observed-adverse-effect level (LOAEL) of 12.5 mg/kg-day were identified from the l.iao
(1989a) and l.iao (1989c) study based on decreased body weights, decreased leukocyte and
lymphocyte counts, increased incidence of testicular atrophy and aspermatogenesis, and
decreased absolute and relative testis weights in male rats orally exposed to
/;-a,a,a-tetrachlorotoluene for 90 days. Females were less sensitive than males, showing only the
decreases in leukocyte and lymphocyte counts and an increase in altered eosinophilic foci in the
liver at the high dose of 25.0 mg/kg-day. There is supportive evidence for body weight,
testicular, and lymphocyte effects from other studies described below (l.iao. 1989b, c; Edwards
et al.. 1985; Rose et al.. 1984).
Support for the effect on body weight is provided by the range-finding study performed
by the same investigators (l.iao. 1989b. c). A LOAEL of 75.0 mg/kg-day with a corresponding
NOAEL of 25.0 mg/kg-day for reduced body weight were identified from this range-finding
study, based on significantly decreased body weight (-21%) in male rats treated by gavage for
14 days. In addition, significant decreases in body weight were observed in both female and
male rats at the high concentration (human equivalent concentration for systemic extrarespiratory
effects [HECer]) of 16.9 mg/m3 in a 30-day inhalation study and in pregnant female rats at the
high concentration (HECer) of 6.30 mg/m3 in a gestational exposure study (Edwards et al.. 1985;
Rose et al .. 1984).
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Testicular effects were prominent at the LOAEL of 12.5 mg/kg-day in the 90-day gavage
study (increased incidence of seminiferous tubular atrophy and aspermatogenesis, with
corresponding decreases in both absolute and relative testes weights) (Xiao. 1989a. c). Data
from other studies provide support for identifying degenerative changes in the testes as a critical
effect of exposure to /;-a,a,a-tetrachlorotoluene: small testes were noted in the 14-day
range-finding study at 150 mg/kg-day (l.iao. 1989b, c), and in a 30-day inhalation study in albino
rats (Rose et at., 1984), significant increases in testicular tubular atrophy and decreased absolute
testis weights were observed in males exposed to a concentration of 16.9 mg/m3 (HECer) of
/;-a,a,a-tetrachlorotoluene for 30 days.
The 90-day gavage study reported significant reductions in leukocyte, and specifically
lymphocyte, populations in male rats at >12.5 mg/kg-day and female rats at 25.0 mg/kg-day
(l.iao. 1989a. c), implying that the immune system is another potential target of
/;-a,a,a-tetrachlorotoluene toxicity. Similar significant reductions in lymphocyte and total
leukocyte counts were observed in male and female rats following exposure to an HECer
concentration of 16.9 mg/m3 ofp-a,a,a-tetrach 1 orotoluene vapor for 30 days (Rose et at., 1984).
Related observations in this study were significant reductions in absolute spleen and thymus
weights in males, and grossly small thymuses and histological findings of thymic involution and
decreased splenic cellularity in both males and females, at 16.9 mg/m3. In the 90-day gavage
study, thymus and spleen weights were not measured, but there were no gross or microscopic
pathology findings in these organs (l.iao. 1989a, c). Immune tissues were also among the
affected tissues in the oral cancer bioassay by Fukuda et at. (1980) and Fukuda et at. (1979),
which found significant increases in incidences of thymomas and malignant lymphomas at
4.9 mg/kg-day (human equivalent dose [HED]), and these were some of the first tumors to form
in exposed animals. The potential mechanisms of carcinogenesis for these immune-related
tumors is unclear, but the tumors provide further evidence that the immune system is a potential
target of/?-a,a,a-tetrachlorotoluene.
Data for the most sensitive endpoints in the 90-day gavage study (increased tubular
atrophy and aspermatogenesis in the testes, decreased absolute and relative testis weights, and
decreased body weights in males, and reduced lymphocyte counts in both males and females)
were modeled using all available continuous or dichotomous models, as appropriate, in the
Benchmark Dose Software (BMDS; Version 2.6). The modeled data are shown in Table A-l.
HEDs in mg/kg-day were used as the dose metric. Benchmark responses (BMRs) were chosen
for each data set in accordance with standard U.S. EPA practice.
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Table A-l. Data for Sensitive Endpoints in Male and Female S-D Rats Exposed Daily to
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days3
ADD (HED) (mg/kg-d)b
Male
0(0)
1.25 (0.342)
12.5 (3.38)
25.0 (6.70)
Male body weight at Week 14 (g);
mean ± SD (n = 10)
543 ±38.8
526 ± 64.0
484 ±45.1
459 ±34.8
Absolute testis weight (g);
mean ± SD (n = 10)
3.41 ±0.399
3.73 ±0.713
2.19 ±0.922
1.25 ±0.138
Relative testis weight (% BW);
mean ± SD (n = 10)
0.662 ±0.086
0.762 ±0.174
0.477 ±0.203
0.291 ±0.048
Total incidence of tubular atrophy and
aspermatogenesis in the testes (n = 10)
0
0
7
10
Incidence of marked tubular atrophy and
aspermatogenesis in the testes (n = 10)
0
0
5
7
Lymphocytes (1057|iL):
mean ± SD (n = 10)
9.73 ±2.65
9.54 ±2.28
6.17 ± 1.4
5.27 ±2.04
Female
0(0)
1.25 (0.299)
12.5 (2.94)
25.0 (5.89)
Lymphocytes (1057|iL):
mean ± SD (n = 10)
7.06 ±2.9
6.16 ± 1.73
5.28 ± 1.9
3.6 ± 1.29
aLiao (1989a. 1989c).
' HEDs were calculated as recommended by U.S. EPA (2011b). HED = ADD x DAF. The DAF is calculated as
follows: DAF = (B Wa1/4 ^ BWt1'4), where B Wa = animal body weight and B Wh = human body weight. A reference
body weight recommended by U.S. EPA (1988) for humans. (70 kg), and study-specific TWA body weights for
male (0.392, 0.375, and 0.362 kg at low, medium, and high doses, respectively) and female (0.229, 0.214, and
0.215 kg at low, medium, and high doses, respectively) rats from each dose group were used for BWh and BWa.
The calculated DAFs for low, medium, and high doses were: 0.274, 0.271, and 0.268 (males) and 0.239, 0.235, and
0.235 (females).
ADD = adjusted daily dose; BW = body weight; DAF = dosimetric adjustment factor; HED = human equivalent
dose; S-D = Sprague-Dawley; SD = standard deviation; TWA = time-weighted average.
Table A-2 summarizes the benchmark dose (BMD) modeling results and provides
candidate points of departure (PODs) for the modeled endpoints. Details of model fit for each
data set are presented in Appendix C.
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Table A-2 Potential PODs in Rats Administered p-a,a,a-Tetrachlorotoluene by Gavage
for 90 Days3
Endpoint
NOAEL (HED)
mg/kg-d
LOAEL (HED)
mg/kg-d
BMDL (HED)b
mg/kg-d
POD (HED)
mg/kg-d
Decreased body weight (M)
0.342
3.38
0.351
0.351 (BMDLio)
Decreased absolute testis weight
(M)
0.342
3.38
NA
0.342 (NOAEL)
Decreased relative testis weight
(M)
0.342
3.38
NA
0.342 (NOAEL)
Increased total incidence of
tubular atrophy and
aspermatogenesis in the testes
(M)
0.342
3.38
0.167
0.167 (BMDLio)
Increased incidence of marked
tubular atrophy and
aspermatogenesis in the testes (M)
0.342
3.38
0.261
0.261 (BMDLio)
Decreased lymphocyte count (M)
0.342
3.38
0.491
0.491 (BMDLio)
Decreased lymphocyte count (F)
3.38
6.70
3.03
3.03 (BMDLio)
aLiao (1989a. 1989c).
bModeling results are described in more detail in Appendix C.
BMDL = benchmark dose lower confidence limit; F = female(s); HED = human equivalent dose;
LOAEL = lowest-observed-adverse-effect level; M = male(s); NA = not applicable;
NOAEL = no-observed-adverse-effect level; POD = point of departure.
Derivation of a Screening Subchronic Provisional Reference Dose
Of the most sensitive endpoints in the 90-day gavage study by (Xiao. 1989a. c) that
provided adequate BMD modeling results, the lowest POD is a 10% benchmark dose lower
confidence limit human equivalent dose (BMDLio [HED]) of 0.167 mg/kg-day for increased
total incidence of tubular atrophy and aspermatogenesis. The data for decreased absolute and
relative testis weight did not provide adequate BMD model fits; thus, the POD for these effects is
a NOAEL of 0.342 mg/kg-day. The BMDLio (HED) of 0.167 mg/kg-day for increased total
incidence of tubular atrophy and aspermatogenesis in the 90-day gavage study (I.iao. 1989a. c)
was selected as the POD for derivation of the screening subchronic provisional reference dose
(p-RfD), because it is the lowest of the prospective PODs and is therefore expected to be
protective against all testicular effects, as well as any potential effects on body weight and the
immune system, following oral exposure to /;-a,a,a-tetrachlorotoluene.
The screening subchronic p-RfD is derived by applying a composite uncertainty factor
(UFc) of 300 (reflecting an interspecies uncertainty factor [UFa] of 3, an intraspecies uncertainty
factor [UFh] of 10, and a database uncertainty factor [UFd] of 10) to the selected POD (HED) of
0.167 mg/kg-day.
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Screening Subchronic p-RfD = POD (HED) UFc
= 0.167 mg/kg-day300
= 6 x 10"4 mg/kg-day
Table A-3 summarizes the uncertainty factors for the screening subchronic p-RfD for
p-a, a, a-tetrachlorotolu ene.
Table A-3. Uncertainty Factors for the Screening Subchronic p-RfD for
/>-a,a,a-Tetrachlorotoluene
UF
Value
Justification
UFa
3
A UFa of 3 (10°5) is applied to account for remaining uncertainty associated with extrapolating
from animals to humans when cross-species dosimetric adjustment (HED calculation) is performed.
UFd
10
A UFd of 10 is applied to account for deficiencies and uncertainties in the database. Relevant oral
studies are limited to a sinsle subchronic-duration toxicity studv in rats (liao. 1989a c) and a 14-d
range-finding study performed by the same researchers (both studies unpublished and not peer
reviewed), although some support is also provided by a short-term-duration inhalation study in rats
(also unpublished) that found effects consistent with those identified in the subchronic-duration oral
study. An oral cancer bioassay in mice is also available but contains no information on noncancer
endpoints. There are no reproductive or developmental studies available by oral exposure. An
unpublished developmental toxicity study by inhalation exposure is available, but the results (fetal
effects suggestive of developmental delay at a concentration that also affected body weight in
dams) are of uncertain significance for oral exposure. Additionally, the thymus has been identified
as a potential toxicity target after inhalation exposure to p-a.a.a-tctrachlorotolucne. suggesting the
possibility of immunotoxicity as a systemic effect; however, an immunotoxicity study is lacking in
the database.
UFh
10
A UFh of 10 is applied to account for human variability in susceptibility, in the absence of
information to assess toxicokinetic and toxicodynamic variability of p-a.a.a-tctrachlorotolucne in
humans.
UFl
1
A UFl of 1 is applied because the POD is a BMDL.
UFs
1
A UFs of 1 is applied because the POD comes from a subchronic-duration study.
UFC
300
Composite UF = UFA x UFD x UFH x UFL x UFS.
BMDL = benchmark dose lower confidence limit; HED = human equivalent dose;
LOAEL = lowest-observed-adverse-effect level; NOAEL = no-observed-adverse-effect level; POD = point of
departure; p-RfD = provisional reference dose; UF = uncertainty factor; UFa = interspecies uncertainty factor;
UFc = composite uncertainty factor; UFD = database uncertainty factor; UFH = intraspecies uncertainty factor;
UFl = LOAEL-to-NOAEL uncertainty factor; UFS = subchronic-to-chronic uncertainty factor.
Derivation of Screening Chronic Provisional Reference Dose
There are no chronic-duration studies on p-a,a,a-tetrach 1 orotoluene that provide adequate
data on noncancer effects. Thus, the screening chronic p-RfD for/;-a,a,a-tetrachlorotoluene is
derived using the same POD (HED) as the screening subchronic p-RfD (0.167 mg/kg-day) with a
UFc of 3,000 (reflecting a UFa of 3, a UFh of 10, a UFd of 10, and a subchronic-to-chronic
uncertainty factor [UFs] of 10 for the use of a subchronic POD).
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Screening Chronic p-RfD = POD (HED) UFc
= 0.167 mg/kg-day ^ 3,000
= 6 x 10"5 mg/kg-day
Table A-4 summarizes the uncertainty factors for the screening chronic p-RfD for
p-a, a, a-tetrachl orotolu ene.
Table A-4. Uncertainty Factors for the Screening Chronic p-RfD for
/>-a,a,a-Tetrachlorotoluene
UF
Value
Justification
UFa
3
A UFa of 3 is applied to account for remaining uncertainty associated with extrapolating from
animals to humans when cross-species dosimetric adjustment (HED calculation) is performed.
UFd
10
A UFd of 10 is applied to account for deficiencies and uncertainties in the database. Relevant oral
studies are limited to a sinsle subchronic-duration toxicity studv in rats (liao. 1989a c) and a 14-d
range-finding study performed by the same researchers (both studies unpublished and not peer
reviewed), although some support is also provided by a short-term-duration inhalation study in rats
(also unpublished) that found effects consistent with those identified in the subchronic-duration oral
study. An oral cancer bioassay in mice is also available but contains no information on noncancer
endpoints. There are no chronic-duration noncancer, reproductive, or developmental studies
available by oral exposure. An unpublished developmental toxicity study is available by inhalation
exposure, but the results (fetal effects suggestive of developmental delay at a concentration that also
affected body weight in dams) are of uncertain significance for oral exposure. Additionally, the
thymus has been identified as a potential toxicity target after inhalation exposure to
/>-a.a.a-tctrachlorotolucnc. suggesting the possibility of immunotoxicity as a systemic effect;
however, an immunotoxicity study is lacking from the database.
UFh
10
A UFh of 10 is applied to account for human variability in susceptibility, in the absence of
information to assess toxicokinetic and toxicodynamic variability of p-a.a.a-tctrachlorotolucne in
humans.
UFl
1
A UFl of 1 is applied because the POD is a BMDL.
UFs
10
A UFs of 10 is applied because of the lack of a chronic-duration study, and a subchronic POD is
being used to estimate a chronic point of departure for the derivation of a screening chronic p-RfD.
UFC
3,000
Composite UF = UFA x UFD x UFH x UFL x UFS.
BMDL = benchmark dose lower confidence limit; HED = human equivalent dose;
LOAEL = lowest-observed-adverse-effect level; NOAEL = no-observed-adverse-effect level; POD = point of
departure; p-RfD = provisional reference dose; UF = uncertainty factor; UFA = interspecies uncertainty factor;
UFc = composite uncertainty factor; UFD = database uncertainty factor; UFH = intraspecies uncertainty factor;
UFl = LOAEL-to-NOAEL uncertainty factor; UFS = subchronic-to-chronic uncertainty factor.
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DERIVATION OF SCREENING INHALATION REFERENCE CONCENTRATIONS
The main body of this PPRTV assessment noted that, because they have not been peer
reviewed, neither the 30-day rat inhalation study by Rose et al. (1984). nor the rat inhalation
developmental toxicity study by Edwards et al. (1985) could be used to derive provisional
reference values. Both studies did, however, appear to be adequately designed and conducted,
and provided dose-response information on endpoints suitable for use in quantitative toxicity
assessment. To account for the uncertainty associated with basing a toxicity assessment on
unpublished studies that have not been peer reviewed, the assessment is considered a
screening-level assessment.
ANOAEL of 3.98 mg/m3 and a LOAEL of 18.9 mg/m3 (analytical vapor concentrations)
were identified for rats in the 30-day inhalation study (Rose et al.. 1984). based on significantly
increased incidence of upper and lower respiratory tract lesions in male and female rats exposed
to /;-a,a,a-tetrachlorotoluene vapors. The lesions showed a dose-response, with severe lesions
occurring only at the high concentration of 94.5 mg/m3. Other significant effects at this high
exposure level were decreases in food and water intake, body and organ weights, and
lymphocyte counts; and increases in incidence of degenerative lesions in the testes, spleen, and
thymus. Gross clinical signs of toxicity and mortality were also observed at this concentration.
In considering the relative sensitivity of the different respiratory lesions, exposure levels
were converted to HECs for both the extrathoracic (ET) region (for upper respiratory lesions)
and for the tracheobronchial (TB) region (for lower respiratory lesions), according to U.S. EPA
(1994) methodology. HECet values (0.142, 0.675, and 2.53 mg/m3 in males, and 0.107, 0.506,
and 2.03 mg/m3 in females) were roughly 10-fold lower than HECtb values. Thus, based on
HECs, the upper respiratory lesions are a more sensitive basis for toxicity assessment than the
lower respiratory lesions. Of the observed upper respiratory lesions, only two lesions occurred at
all exposure levels: atrophy of olfactory epithelium in males and keratinizing epithelial
hyperplasia over arytenoid projections in the larynx in females. Data for both of these lesions
were modeled by all available dichotomous models in BMDS (Version 2.6), using the
corresponding HECet values. Other lesions considered for modeling were epithelial
hyperplasia/metaplasia in the ventrolateral region of the larynx of males, and focal atrophy of the
olfactory epithelium in females. Neither of these lesions occurred in the low-exposure group, but
both were significantly increased in the middle-exposure group. However, neither of these data
sets was suitable for BMD modeling because incidence jumped from 0% in the control and
low-exposure groups, to 80-100% in the middle- and high-exposure groups, with no
intermediate values to inform the shape of the dose-response curve in the low-dose region.
The modeled data are shown in Table A-5. For atrophy of the olfactory epithelium in
male rats, incidences were reported by severity grade in the original study. Those data were
combined to give total incidence of the lesion, which was the data set modeled here. Modeling
was performed using the standard reporting BMR for dichotomous data of 10% extra risk.
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Table A-5. Data for Sensitive Endpoints in Male and Female Albino (CR:WI BR) Rats
Exposed to />-a,a,a-Tetrachlorotoluene Vapor 5 Days/Week, 6 Hours/Day, for 30 Days3
HECet (mg/m3)b
Males
0
0.142
0.675
2.53
Atrophy of olfactory epithelium
Focal
Severe
Total0
0/5
0/5
0/5
1/5
0/5
1/5
3/5
1/5
4/5*
0/6
6/6
6/6*
Females
0
0.107
0.506
2.03
Keratinizing epithelial hyperplasia
in the larynx
0/5
1/5
2/5
5/5*
aRose et at (1984).
' HECin was calculated using the equation for ET effects from a Category 1 gas (U.S. EPA. 19941. HECet = TWA
concentration (mg/m3) x RGDREt, where RGDREt is the extrathoracic regional gas dose ratio (animal:human).
RGDRet was calculated as per U.S. EPA (1994) using default human VE and human and animal respiratory tissue
surface area values and animal VE values calculated from TWA body weights for each dose group in the study.
TWA body weights (grams) for the 0, 3.98, 18.9, and 94.5 mg/m3 groups, respectively, were: males = 303.6, 304.7,
298.1, and 201.2; female = 203.2, 203.4, 202.5, and 159.5.
Total incidence was modeled by EPA.
*Statiscially significant (p < 0.05) based on Fisher's exact test, as conducted for this review.
ET = extrathoracic; HEC = human equivalent concentration; RGDR = regional gas dose ratio;
TWA = time-weighted average; Ve = minute volume.
In the developmental toxicity study (Edwards et al.. 1985). a maternal NO A EL of
6.30 mg/m3 (HEC) was identified. Although absolute maternal body weight was reduced at
6.30 mg/m3, this reduction was less than 10%. Thus, a maternal LOAEL was not identified. The
fetal NOAEL and LOAEL were established at 2.60 mg/m3 and 6.30 mg/m3 (HEC), respectively,
based on decreased mean fetal weight and increased incidence of unossified sternebrae in the
fetuses of dams exposed to/;-a,a,a-tetrachlorotoluene for 6 hours/day on GDs 6-19.
Fetal-weight data were not reported in sufficient detail to perform BMD modeling, but the study
did include individual animal data that were used to perform BMD modeling of the incidence of
fetal unossified sternebrae by the nested models in BMDS. ABMR of 5% extra risk was used.
The individual animal data used to perform the modeling are shown in Appendix C.
Table A-6 summarizes the BMD modeling results and provides candidate PODs for the
modeled endpoints. Details of model fit for each data set are presented in Appendix C.
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Table A-6. Potential PODs in Rats Administered p-a,a,a-Tetrachlorotoluene by Inhalation
Exposure
Endpoint
NOAEL (HEC)
mg/m3
LOAEL (HEC)
mg/m3
BMCL (HEC)a
mg/m3
POD (HEC)
mg/m3
Increased total incidence of atrophy
of the olfactory epithelium (M)b
0.142
0.675
0.0141
0.0141
(BMCLio)
Increased incidence of keratinizing
epithelial hyperplasia in the larynx (F)b
0.506
2.03
0.0182
0.0182
(BMCLio)
Increased incidence of unossified
sternebrae0
2.60
6.30
0.385
0.385
(BMCLos)
aModeling results are described in more detail in Appendix C.
bRose et at (1984).
°Edwards et al. (1985).
BMCL = benchmark concentration lower confidence limit; F = female(s); HEC = human equivalent concentration;
LOAEL = lowest-observed-adverse-effect level; M = male(s); NOAEL = no-observed-adverse-effect level;
POD = point of departure.
Derivation of a Screening Subchronic Provisional Reference Concentration
Of the most sensitive endpoints observed following inhalation exposure to
/>a,a,a-tetrachlorotoluene that provided adequate BMD modeling results, the lowest POD is a
BMCLio (HEC) of 0.0141 mg/m3 for increased incidence of atrophy of the olfactory epithelium
in male rats in the 30-day inhalation study (Rose et al.. 1984). Thus, the BMCLio (HEC) of
0.0141 mg/m3 was selected as the POD for derivation of the screening subchronic p-RfC. The
POD based on increased incidence of atrophy of the olfactory epithelium was slightly lower than
the potential POD based on laryngeal hyperplasia in females in this same study, and an order of
magnitude lower than the potential POD based on unossified sternebrae in the developmental
toxicity study (Edwards et al.. 1985). Thus, the POD based on increased incidence of atrophy of
the olfactory epithelium is expected to be protective against all respiratory effects, as well as any
potential developmental effects, following inhalation exposure to/;-a,a,a-tetrachlorotoluene.
The screening subchronic p-RfC is derived by applying a UFc of 300 (reflecting a UFa of
3, a UFh of 10, and a UFd of 10) to the selected POD of 0.0141 mg/m3.
Screening Subchronic p-RfC = POD (HEC) - UFc
= 0.0141 mg/m3-300
= 5 x 10"5 mg/m3
Table A-7 summarizes the uncertainty factors for the screening subchronic p-RfC for
p-a, a, a-tetrachl orotolu ene.
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Table A-7. Uncertainty Factors for the Screening Subchronic p-RfC for
/>-a,a,a-Tetrachlorotoluene
UF
Value
Justification
UFa
3
A UFa of 3 (10°5) is applied to account for remaining uncertainty associated with extrapolating
from animals to humans when cross-species dosimetric adjustment (HEC calculation) is performed.
UFd
10
A UFd of 10 is applied to account for deficiencies and uncertainties in the database. The inhalation
database for /:>-«. u.u-tctrachlorotolucnc is limited to one 30-d toxicity study and one developmental
toxicity studv in rats (Edwards et al.. 1985; Rose et al.. 1984). neither of which was published or
peer reviewed. No longer, subchronic- or chronic-duration inhalation studies were located. The
inhalation database is also lacking a multigenerational reproductive study and a developmental
toxicity study in a second species. Additionally, the thymus has been identified as a potential
toxicity target after inhalation exposure to /:>-«. u.u-tctrachlorotolucnc: however, an immunotoxicity
study is lacking from the database.
UFh
10
A UFh of 10 is applied to account for human variability in susceptibility, in the absence of
information to assess toxicokinetic and toxicodynamic variability of /?-u. u.u-tctrachlorotolucnc in
humans.
UFl
1
A UFl of 1 is applied because the POD is a BMCL.
UFS
1
A UFS of 1 is applied because the POD was derived from a 30-d study.
UFC
300
Composite UF = UFA x UFD x UFH x UFL x UFS.
BMCL = 95% lower confidence limit on the benchmark concentration; HEC = human equivalent concentration;
LOAEL = lowest-observed-adverse-effect level; NOAEL = no-observed-adverse-effect level; POD = point of
departure; p-RfC = provisional reference concentration; UF = uncertainty factor; UFa = interspecies uncertainty
factor; UFC = composite uncertainty factor; UFD = database uncertainty factor; UFH = intraspecies uncertainty
factor; UFL = LOAEL-to-NOAEL uncertainty factor; UFS = subchronic-to-chronic uncertainty factor.
Derivation of a Screening Chronic Provisional Reference Concentration
There are no chronic-duration inhalation studies on/;-a,a,a-tetrachlorotoluene. The
30-day study used for deriving the screening subchronic p-RfC (Rose et al.. 1984) is too limited
in duration to support derivation of a screening chronic p-RfC. Use of a
less-than-subchronic-duration study is highly uncertain with respect to deriving chronic toxicity
values unless there are chronic toxicity data available to suggest that the critical effect observed
in the short-term-duration study will not increase in severity or become more sensitive based on
dose-response analysis following longer treatment duration. In the absence of any supporting
chronic toxicity data, it is unclear that a POD based on the short-term-duration inhalation study
by Rose et al. (1984) or the developmental toxicity study by Edwards et al. (1985) would protect
against chronic effects. Therefore, a screening chronic p-RfC was not derived for
p-a, a, a-tetrachl orotolu ene.
DERIVATION OF PROVISIONAL SCREENING CANCER POTENCY VALUES
Derivation of a Screening Provisional Oral Slope Factor
As discussed in the main body of the report, a provisional oral slope factor (p-OSF) was
not derived because U.S. EPA could find no evidence that the Fukuda et al. (1980) study was
peer reviewed. In addition the study duration was much less than lifetime duration, requiring the
application of an adjustment factor to account for the expected increase in the tumor incidence
rate with increasing age (U.S. EPA, 1980), substantially increasing the uncertainty.
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Fukuda et al. (1980) observed significant dose-related trends for increased incidence of
multiple tumor types in female mice exposed to/;-a,a,a-tetrachlorotoluene by gavage for
17.5 weeks and observed for up to 18 months, including adenocarcinomas and multiple
adenomas in the lungs, thymomas, malignant lymphomas, multiple papillomas, squamous cell
carcinomas and carcinomas in situ in the forestomach, and squamous cell carcinomas in the skin
(see Tables A-8 and B-8).
Table A-8. Incidence Data for Significantly Increased Tumors in Female ICR Mice Orally
Exposed to />-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
HED (mg/kg-d)
Endpoint
0
0.028
0.072
0.18
0.44
1.1
Tumor incidence/total effective number of animals
Forestomach:
Squamous cell carcinoma
0/26
0/22
0/28
0/22
6/29
7/29
Carcinoma in situ
0/26
0/22
0/28
1/22
4/29
3/29
Multiple papilloma
0/26
2/22
4/28
5/22
2/29
1/29
Lung:
Adenocarcinoma
0/26
3/22
7/28
10/22
15/29
2/29
Multiple adenoma
1/26
2/22
1/28
6/22
10/29
17/29
Thymoma
0/26
0/22
0/28
0/22
4/29
8/29
Malignant lymphoma
1/26
0/22
1/28
0/22
0/29
5/29
Skin:
Squamous cell carcinoma
0/26
0/22
0/28
0/22
0/29
6/29
aFukuda et al. (1980): Fukuda et al. (1979).
HED = human equivalent dose.
BMD modeling was performed for each of these tumor types individually. It was not
possible to combine data for multiple tumor types in a given tissue because tumor data from
individual animals were not provided, and the reporting of multiple tumor types in a single
animal could not be ruled out. The MSCombo model was used to evaluate the composite risk
for developing any combination of tumors at any site within a single study. The MSCombo
model was run using the incidence data for the individual tumor types and the polydegrees
identified in the model runs for the individual tumor types. Including all tumor types in the
combined tumor BMD analysis using the MS Combo model could result in an overestimate of
the screening p-OSF. The potential for "double-counting" of related tumors in the forestomach
exists primarily at the highest two doses, where there is more than one tumor of each type. There
is a greater potential for double-counting in the lung, with multiple tumors of each type at most
exposure levels. Also, despite the observed differences in survival (reported as months to
50% mortality) across groups, it was not possible to perform any adjustments for differential
mortality across groups due to the lack of individual animal data. Multistage cancer models in
the U.S. EPABMDS (Version 2.6) were fit to the incidence data for each tumor. The BMR used
was 10% extra risk. The HED in mg/kg-day was used as the dose metric, and modeling results
are summarized in Table A-9 (see additional BMD details in Appendix C).
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Table A-9. Modeling Results Based on the Incidence of Tumors in Female ICR Mice
Orally Exposed to />-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
Tumor Endpoint
Selected Model
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Potential p-OSF
(mg/kg-d)1
Lung adenocarcinoma
Multistage (1-degree);
high-dose group dropped
0.047
0.033
3.0 x 10°
Lung multiple adenoma
Multistage (1-degree)
0.127
0.092
1.1 x 10°
Thymoma
Multistage (1-degree)
0.402
0.258
3.9 x 10-1
Malignant lymphoma
Multistage (1-degree)
0.979
0.727
1.5 x 10-1
Forestomach multiple
papillomas
Multistage (1-degree)
0.0569
0.0359
2.8 x 10°
Forestomach squamous cell
carcinoma
Multistage (1-degree)
0.372
0.243
4.1 x 10-1
Forestomach carcinoma in situ
Multistage (1-degree)
0.640
0.376
2.7 x 10-1
Skin squamous cell carcinoma
Multistage (1-degree)
0.957
0.721
1.5 x 10-1
Combined tumors
MS Combo
0.019
0.015
6.8 x 10°
aFukuda et at (1980): Fukuda et al. (1979).
BMD = benchmark dose; BMDL = 95% lower confidence limit on the benchmark dose (subscripts denote
benchmark response: i.e., 10 = dose associated with 10% extra risk); HED = human equivalent dose;
p-OSF = provisional oral slope factor.
The Multistage cancer model (1-degree) provided an adequate fit to the data sets for lung
adenocarcinomas, lung multiple adenomas, forestomach carcinoma in situ, carcinomas in the
forestomach, and thymomas (see Table A-9). The higher degree polynomial models took the
form of the 1 -degree models for these tumors. For lung adenocarcinomas, it was necessary to
drop the high-dose data to obtain an adequate fit. This is due to the low incidence of these
tumors in the highest-dose group, which reflects the relatively late development of this tumor
and the high early mortality observed in this group due to quicker developing tumors (malignant
lymphoma, thymoma, and forestomach carcinomas). Similarly, the forestomach multiple
papilloma data could be fit adequately only by dropping the two highest doses (1-degree
Multistage model). Although two doses had to be dropped, forestomach multiple papillomas
were included in the multiple tumor analysis because of the strong dose-response trend
(p = 0.0075) for the lower doses and the second highest potential unadjusted screening p-OSF.
From the Multistage cancer models, predicted BMDs associated with 10% extra risk
(BMDio) and their 95% lower confidence limits (BMDLio) for the individual tumor types ranged
from 0.047 and 0.033 mg/kg-day (HED), respectively, for lung adenocarcinoma to 0.979 and
0.727 mg/kg-day (HED) for malignant lymphoma. The combined tumor model resulted in
BMDio and BMDLio estimates of 0.019 and 0.015 mg/kg-day (HED). The lowest BMDLio
value of 0.015 mg/kg-day (HED) based on the combined tumor risk was selected as the point of
departure (POD) for deriving the screening p-OSF.
In the absence of data for the MOA of/;-a,a,a-tetrachlorotoluene-induced tumorigenesis,
the unadjusted screening p-OSF for /;-a,a,a-tetrachlorotoluene, based on the BMDLio (HED) of
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0.015 mg/kg-day for combined tumors in female mice treated with/;-a,a,a-tetrachlorotoluene for
17.5 weeks, was derived using a linear approach as follows:
Screening p-OSF (Unadjusted) = BMR ^ BMDLio (HED)
= 0.1 0.015 mg/kg-day
= 6.8 x 10° (mg/kg-day)"1
An adjustment was applied to account for the shorter-than-lifetime observation period
(U.S. EPA, 1980). The Fukuda et al. (1980) bioassay was terminated after 18 months (compared
to the reference mouse lifespan of 24 months) due to early mortality associated with tumor
formation. Due to the less-than-lifetime duration of the study, it cannot be known how an
increased duration (i.e., the full 2-year lifetime exposure) might have influenced the tumor
incidence in the low-dose treated rats. Therefore, an adjustment factor of (L Le)3 was applied
to the unadjusted screening p-OSF, where L = the lifetime of the animal and Le = the duration of
experimental dosing (U.S. EPA. 1980). Using this adjustment, an adjusted screening p-OSF is
derived as follows:
Screening p-OSF (Adjusted) = Screening p-OSF (unadjusted) x (L Le)3
= 6.8 x 10° (mg/kg-day)-1 x (24 months 18 months)3
= 1.6 x 101 (mg/kg-day)"1
The adjusted screening p-OSF should not be used with exposure exceeding the POD
(0.015 mg/kg-day) because at doses higher than this value, the fitted dose-response model better
characterizes the dose-response relationship. As mentioned previously, there is considerable
uncertainty associated with the screening p-OSF due to the large difference between actual
exposure time and study duration, with respect to dose averaging, and application of a
less-than-lifetime adjustment factor. Averaging the doses over the full study duration is a
common practice that assumes that the carcinogenic outcome is a linear function of total dose,
rather than dose rate; that is, a large dose over a short time period is equivalent to a smaller dose
over a longer time period (U.S. EPA. 2005). An alternative that uses the 17.5-week average
exposure (not averaging over 18 months) would result in a much larger less-than-lifetime
adjustment factor. As some adjustment to the effective dose is necessary based on both the
2005 Cancer Guidelines and the unique, short treatment duration in the study by Fukuda et al.
(1980) [necessitating a less-than-lifetime adjustment factor per U.S. EPA (1980)1. the selected
approach was determined to be the least uncertain.
Derivation of a Provisional Inhalation Unit Risk
Derivation of quantitative estimates of cancer risk following inhalation exposure to
/;-a,a,a-tetrachlorotoluene is precluded by the absence of inhalation data for this compound.
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APPENDIX B. DATA TABLES
Table B-l. Body Weight and Body-Weight Gain in Male and Female Rats Orally Exposed
to />-a,a,a-Tetrachlorotoluene for 14 Days3
Study Day
1
8
15
Dose (mg/kg-d)
Male Body Weight (g)b'c
0
187 ± 13.6
230 ± 14.7
273 + 12.6
1.25d
201 ± 11.7 (+8%)
262 ± 11.7** (+14%)
309 + 18.4** (+13%)
12.5d
201 ± 16.2 (+8%)
263 ± 17.7** (+14%)
312+19.2** (+14%)
25.0
185 ± 11.9 (-1%)
220+ 11.8 (-4%)
249+ 11.3 (-9%)
75.0
187 ± 9.2 (0%)
197+10.3** (-14%)
217+17.8** (-21%)
150
186 ± 10.8 (-1%)
167 + 18** (-27%)
169 + 10** (-38%)
300e
183 ± 10.5 (-2%)
NDr
NDr
Dose (mg/kg-d)
Female Body Weight (g)
0
133 ±8.0
159+11.7
175+18.4
1.25d
137 ± 9.3 (+3%)
159 + 10.08 (0%)
172 + 16.8 (-2%)
12.5d
136 ± 7.5 (+2%)
158 + 7.4 (-1%)
172 + 5.8 (-2%)
25.0
136 ± 6.3 (+2%)
156 + 10.4 (-2%)
168 + 8.9 (-4%)
75.0
134 ± 7.4 (+1%)
140+10.3* (-12%)
156+ 11.6 (-11%)
150
132 ± 7.4 (-1%)
124 + 14.7** (-22%)
132 + 18** (-25%)
300e
134 ± 8.4 (+1%)
NDr
NDr
40
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FINAL
September 2019
Table B-l. Body Weight and Body-Weight Gain in Male and Female Rats Orally Exposed
to />-a,a,a-Tetrachlorotoluene for 14 Days3
Dose (mg/kg-d)
Body-Weight Gain (g)
Male
Female
Week 1 (D 1-7)
Week 2 (D 8-15)
Week 1 (D 1-8)
Week 2 (D 8-15)
0
43 ±4.7
43 + 3.1
26 + 5.8
17 + 7.8
1.25d
61 ± 3.9* (+42%)
47+11.9 (+9%)
22 + 5.5 (-15%)
14 + 8.7 (-18%)
12.5d
62 ± 7.3** (+44%)
49 + 8.3 (+14%)
22 + 2.5 (-15%)
14 + 3.5 (-18%)
25.0
36 ± 4.2* (-16%)
29 + 10** (-33%)
20 + 5.7 (-23%)
13+6.1 (-24%)
75.0
10 ± 3** (-77%)
20 + 7.8** (-54%)
7+11.3** (-73%)
16 + 3.6 (-6%)
150
-17 ± 18.5** (-141%)
2 + 10.8** (-95%)
-8+14.7** (-131%)
8 + 8.2 (-53%)
300e
NDr
NDr
NDr
NDr
aLiao (1989b. 1989c).
bData are mean ± SD; n = 6/group on Day 1, and 5/group at 150 mg/kg-day, and 6/group for other dose groups on
Days 8 and 15.
°Value in parentheses is % change relative to control = ([treatment mean - control mean] + control mean) x 100.
dData from these doses were obtained from a second experiment (Experiment 2) without a concurrent control.
Comparisons and statistical analysis shown here were done for this review using the control data shown from
Experiment 1.
eAll animals from the 300-mg/kg-day group died prior to Day 8.
* Significantly different from controls at the same time point by unpaired /-test (p < 0.05), as conducted for this
review.
**Significantly different from controls at the same time point by unpaired /-test (p < 0.01), as conducted for this
review.
NDr = not determined (all animals from the 300-mg/kg-day group died prior to Day 8); SD = standard deviation.
41
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September 2019
Table B-2. Weekly Food Consumption in Male and Female Rats Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 14 Days3
Study Day
1-8 (Week 1)
8-15 (Week 2)
Dose (mg/kg-d)
Male Food Consumption (g/animal-d)b'c
0
22 ± 1
22+1.3
1.25d
28 ± 1.4** (+27.3%)
27 + 2.5** (+22.7%)
12.5d
28 ± 2.2** (+27.3%)
28 + 2.2** (+27.3%)
25.0
21+0.6 (-4.5%)
20+1.1 (-9.1%)
75.0
17+1.8** (-22.7%)
16 + 2.6** (-27.3%)
150
12 + 4** (-45.5%)
12+1.3** (-45.5%)
300e
NDr
NDr
Dose (mg/kg-d)
Female Food Consumption (g/animal-d)
0
17+1.5
16 + 2
1.25d
18+1.3 (+5.9%)
17+ 1.6 (+6.3%)
12.5d
17 + 0.6 (0%)
18 + 0.8 (+12.5%)
25.0
16 + 0.9 (-5.9%)
16+1.1 (0%)
75.0
13+ 2.6** (-23.5%)
15 + 2 (-6.3%)
150
10 + 2.3** (-41.2%)
11+2.5** (-31.3%)
300e
NDr
NDr
aLiao (1989b. 1989c).
bData are mean ± SD; n = 5/group at 150 mg/kg-day and 6/group for other dose groups.
°Value in parentheses is % change relative to control = ([treatment mean - control mean] + control mean) x 100.
dData from these doses were obtained from a second experiment (Experiment 2) without a concurrent control.
Comparisons and statistical analysis shown here were done for this review using the control data shown from
Experiment 1.
eAll animals from the 300-mg/kg-day group died prior to Day 8.
* Significantly different from controls at the same time point by unpaired /-test (p < 0.05), as conducted for this
review.
**Significantly different from controls at the same time point by unpaired /-test (p < 0.01), as conducted for this
review.
NDr = not determined (all animals from the 300-mg/kg-day group died prior to Day 8); SD = standard deviation.
42
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September 2019
Table B-3. Absolute and Relative Organ Weights in Male and Female Rats Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 14 Days3
Male Absolute Organ Weights (g)b'c
Dose (mg/kg-d)
Adrenals
Testes
Kidneys
Liver
0
0.0507 ±0.01405
2.56 + 0.207
2.88 + 0.251
14.91 + 1.047
1.25d
0.0738 ±0.01355* (+46%)
2.74 + 0.193 (+7%)
3.51 +0.345** (+22%)
18.14+ 1.954** (+22%)
12.5d
0.0780 ±0.01707* (+54%)
2.78 + 0.068 (+9%)
3.44 + 0.413* (+19%)
19.02+ 1.903** (+28%)
25.0
0.0554 ±0.01229 (+9%)
2.67 + 0.191 (+4%)
2.75 + 0.244 (-5%)
13.21 + 1.301* (-11%)
75.0
0.0582 ± 0.00949 (+15%)
2.28 + 0.157* (-11%)
2.41+0.221** (-16%)
12.93 + 1.075** (-13%)
150
0.0761 ±0.01355* (+50%)
1.77 + 0.203** (-31%)
2.44 + 0.180** (-15%)
11.54 + 0.503** (-23%)
300e
NDr
NDr
NDr
NDr
Male Relative Organ Weights (% BW)
Dose (mg/kg-d)
Adrenals
Testes
Kidneys
Liver
0
0.019 ±0.0049
0.940 + 0.0657
1.055 + 0.0767
5.478 + 0.4811
1.25d
0.024 ± 0.0044 (+26%)
0.892 + 0.0937 (-5%)
1.139 + 0.0933 (+8%)
5.867 + 0.2998 (+7%)
12.5d
0.025 ± 0.0060 (+32%)
0.893 + 0.0659 (-5%)
1.098 + 0.0916 (+4%)
6.089 + 0.4582* (+11%)
25.0
0.022 ± 0.0050 (+16%)
1.074 + 0.0836* (+14%)
1.104 + 0.0676 (+5%)
5.304 + 0.3541 (-3%)
75.0
0.027 ± 0.0038* (+42%)
1.053 + 0.0974* (+12%)
1.112 + 0.0900 (+5%)
5.978 + 0.4699 (+9%)
150
0.045 ±0.0081** (+137%)
1.053 +0.1391 (+12%)
1.448 + 0.0922** (+37%)
6.845 + 0.3294** (+25%)
300e
NDr
NDr
NDr
NDr
Female Absolute Organ Weights (g)
Dose (mg/kg-d)
Adrenals
Ovaries
Kidneys
Liver
0
0.0587 + 0.00881
0.0853 +0.01852
1.99 + 0.222
9.35+ 1.628
1.25d
0.0818 ±0.01559** (+39%)
0.1216 + 0.02334* (+43%)
2.13+0.216 (+7%)
9.24+ 1.292 (-1%)
12.5d
0.0771 +0.01956 (+31%)
0.1236 + 0.01680** (+45%)
2.09 + 0.101 (+5%)
9.34 + 0.367 (0%)
25.0
0.0694 + 0.01464 (+18%)
0.0913 + 0.03204 (+7%)
2.03 +0.195 (+2%)
9.16 + 0.759 (-2%)
75.0
0.0641+ 0.01199 (+9%)
0.0990 + 0.02423 (+16%)
1.97 + 0.089 (-1%)
9.64 + 0.569 (+3%)
43
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FINAL
September 2019
Table B-3. Absolute and Relative Organ Weights in Male and Female Rats Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 14 Days3
Male Absolute Organ Weights (g)b'c
Dose (mg/kg-d)
Adrenals
Testes
Kidneys
Liver
150
0.0762 ±0.01593* (+30%)
0.0607 + 0.01741* (-29%)
1.85 + 0.154 (-7%)
9.12+ 1.072 (-3%)
300e
NDr
NDr
NDr
NDr
Female Relative Organ Weights (% BW)
Dose (mg/kg-d)
Adrenals
Ovaries
Kidneys
Liver
0
0.034 ± 0.0067
0.049 + 0.0129
1.142 + 0.1211
5.317 + 0.5665
1.25d
0.047 ± 0.0070** (+38%)
0.07 + 0.0110** (+43%)
1.236 + 0.0761 (+8%)
5.345 + 0.3393 (+1%)
12.5d
0.045 ±0.0122 (+32%)
0.072 + 0.0098** (+47%)
1.213 +0.0365 (+6%)
5.435 + 0.2357 (+2%)
25.0
0.041 +0.0090 (+21%)
0.055 + 0.0188 (+12%)
1.210 + 0.1093 (+6%)
5.450 + 0.3490 (+3%)
75.0
0.042 + 0.0095 (+24%)
0.064 + 0.0176 (+31%)
1.268 + 0.0753 (+11%)
6.201 +0.4663* (+17%)
150
0.059 + 0.0188* (+74%)
0.046 + 0.0106 (-6.1%)
1.415 + 0.1015** (+24%)
6.944 + 0.3126** (+31%)
300e
NDr
NDr
NDr
NDr
aLiao (1989b. 1989c).
bData are mean ± SD; n = 5/group at 150 mg/kg-day and 6/group for other dose groups.
°Value in parentheses is % change relative to control = ([treatment mean - control mean] + control mean) x 100.
dData from these doses were obtained from a second experiment (Experiment 2) without a concurrent control. Comparisons and statistical analysis shown here were
done for this review using the control data shown from Experiment 1.
eAll animals from the 300-mg/kg-day group died prior to Day 15 necropsy.
* Significantly different from controls by unpaired t-test (p < 0.05), as conducted for this review.
**Significantly different from controls by unpaired /-test (p < 0.01), as conducted for this review.
BW = body weight; NDr = not determined (all animals from the 300-mg/kg-day group died prior to Day 15 necropsy); SD = standard deviation.
44
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FINAL
September 2019
Table B-4. Select Weekly Body Weight and Body-Weight Gain Data of Male and Female
Rats Orally Exposed to />-a,a,a-Tetrachlorotoluene for 90 Days3
Dose (mg/kg-d)
0
1.25
12.5
25.0
Male Body Weight (g)b'c
Wk 7
412 ±26.6
398 ±48.1 (-3%)
383 ± 32.7 (-7%)
373 ±25.1* (-10%)
Wk 8
436 ±28.3
420 ±45.8 (-4%)
402 ± 32.6 (-8%)
389 ±28.7* (-11%)
Wk 9
453 ±30.6
441 ±43.2 (-3%)
418 ±36.9 (-8%)
405 ±31.6* (-11%)
Wk 10
479 ±31.3
464 ± 50.9 (-3%)
436 ± 38.5* (-9%)
422 ± 27.9** (-12%)
Wk 11
496 ±34.9
482 ± 56.3 (-3%)
452 ± 39.5 (-9%)
434 ± 28.4** (-13%)
Wk 12
514 ± 35.8
495 ± 60.2 (-4%)
466 ±41.2* (-9%)
444 ± 28.4** (-14%)
Wk 13
530 ±37.9
512 ±63.4 (-3%)
477 ±43.5* (-10%)
453 ± 32.4** (-15%)
Wk 14
543 ±38.8
526 ± 64.0 (-3%)
484 ±45.1* (-11%)
459 ± 34.8** (-15%)
Female Body Weight (g)
Wk 7
239 ± 19.4
238 ± 19.3 (-0.4%)
220 ± 12.3 (-8%)
221 ± 17.7 (-8%)
Wk 8
247 ±21.4
245 ± 20.4 (-0.8%)
227 ±13.7 (-8%)
226 ± 18.9* (-9%)
Wk 9
252 ±20.4
250 ± 22.2 (-0.8%)
230 ± 13.7* (-9%)
230 ± 19.8* (-9%)
Wk 10
261 ±22.7
257 ±21.6 (-2%)
235 ± 12.9* (-10%)
239 ±21.6 (-8%)
Wk 11
267 ± 24
265 ±21.8 (-0.7%)
240 ± 12.6* (-10%)
246 ±25.5 (-8%)
Wk 12
271 ±24.4
268 ±23.1 (-1%)
246 ± 14.5 (-9%)
254 ±33.3 (-6%)
Wk 13
273 ± 24
270 ± 23.6 (-1%)
247 ± 14.6 (-10%)
258 ± 38 (-6%)
Wk 14
279 ± 26
275 ± 23.4 (-1%)
252 ± 13.1 (-10%)
263 ± 39 (-6%)
Male Body-Weight Gain (g)
Wk 7-8
24 ± 3.1
22 ± 10.2 (-8%)
19 ±4.3 (-21%)
17 ± 5.2* (-29%)
Wk 8-9
17 ±8.5
21 ± 7.0 (+23%)
16 ± 6.4 (-6%)
16 ± 5.3 (-6%)
Wk 9-10
26 ±6.1
22 ± 10.2 (-15%)
18 ±5.1 (-31%)
17 ± 7.8* (-35%)
Wk 10-11
17 ± 6.1
19 ± 6.4 (+13%)
17 ± 4.6 (0%)
12 ± 4.0 (-29%)
Wk 11-12
18 ±2.9
13 ± 7.6 (-28%)
13 ± 6.5 (-28%)
11 ±3.5* (-39%)
Wk 12-13
16 ±3.4
16 ±6.1 (0%)
12 ± 5.9 (-25%)
8.0 ±8.1* (-50%)
Wk 13-14
13 ±2.9
14 ±6.1 (+8%)
7.0 ± 5.7* (-46%)
6.0 ±5.3* (-54%)
Female Body-Weight Gain (g)d
Wk 1-2
23 ±3.3
19 ±3.8 (-17%)
17 ± 5.4* (-26%)
14 ± 5.8** (-39%)
Wk 5-6
16 ±3.5
13 ± 5.5 (-19%)
7 ± 2.5** (-56%)
7 ± 5.2** (-56%)
aLiao (1989a. 1989c).
bData are mean ± SD; n = 10/group.
°Value in parentheses is % change relative to control = ([treatment mean - control mean] + control mean) x 100.
dSelect treatment weeks with statistically significant differences, compared with controls.
* Significantly different from control (p < 0.05), as reported by the study authors.
**Significantly different from control (p < 0.01), as reported by the study authors.
SD = standard deviation.
45
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September 2019
Table B-5. Terminal Hematology Data in Male and Female Rats Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 90 Days3' b
Endpoint
Dose (mg/kg-d)c'd
0
1.25
12.5
25.0
Male
Erythrocytes (10'7|iL)
9.34 ±0.506
9.45 ±0.295
(+1%)
9.4 ±0.35
(+1%)
8.82 ±0.305*
(-6%)
Hct (%)
48.59 ± 1.98
49.44 ± 1.68
(+2%)
48.9 ± 1.09
(+1%)
46.51 ± 1.53*
("4%)
Hb (g/dL)
16.24 ±0.66
16.74 ±0.67
(+3%)
16.62 ±0.51
(+2%)
15.70 ±0.64
(-3%)
Leukocytes (1057|iL)
11.66 ±2.59
12 ±3.29
(+3%)
7.63 ± 1.37**
(-35%)
7.86 ±2.19**
(-33%)
Lymphocytes (1057|iL)
9.73 ±2.65
9.54 ±2.28
(-2%)
6.17 ± 1.4**
(-37%)
5.27 ±2.04**
(-46%)
Female
Leukocytes (107|iL)
8.11 ±2.81
7.25 ±2.17
("11%)
6.29 ± 1.99
(-22%)
4.25 ± 1.36**
(-48%)
Lymphocytes C103/j.iL)
7.06 ±2.9
6.16 ± 1.73
(-13%)
5.28 ± 1.9
(-25.2%)
3.6 ± 1.29**
(-49%)
aLiao (1989a. 1989c).
bNo statistically significant changes in hematology parameters between treated and control animals were observed
on Day 5 prior to study initiation.
Data are mean ± SD; n = 10/group.
dValue in parentheses is % change relative to control = ([treatment mean - control mean] control mean) x 100.
* Significantly different from control (p < 0.05), as reported by the study authors.
**Significantly different from control (p < 0.01), as reported by the study authors.
Hb = hemoglobin; Hct = hematocrit; SD = standard deviation.
46
p-a, a, a-T etrachl orotoluene
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FINAL
September 2019
Table B-6. Absolute and Relative Organ Weights in Male and Female Rats Orally
Exposed to />-a,a,a-Tetrachlorotoluene for 90 Days3
Endpoint
Dose (mg/kg-d)b'c
0
1.25
12.5
25.0
Male Absolute Organ Weights (g)
Brain
2.22 ±0.072
2.21 ± 0.151
(-1%)
2.18 + 0.139
(-2%)
2.20 + 0.121
(-1%)
Adrenal glands
0.0705 ±0.00811
0.0712 ±0.01491
(+0.9%)
0.0648 + 0.01807
(-8%)
0.0676 + 0.02004
("4%)
Testes
3.41 ±0.399
3.73 ±0.713
(+9%)
2.19 + 0.922**
(-36%)
1.25 + 0.138**
(-63%)
Kidneys
3.78 ±0.528
4.02 ±0.351
(+6%)
3.87 + 0.636
(+2%)
3.96 + 0.437
(+5%)
Liver
16.99 ±2.184
16.92 ±3.026
(0%)
16.62 + 3.364
(-2%)
16.63+2.11
(-2%)
Necropsy body weight
517 ±38.4
498 ±62.4
("4%)
461 + 44.3f
("11%)
434 + 33.If
(-16%)
Male Relative Organ Weights (% BW)
Brain
0.431 ±0.0327
0.448 ±0.0453
(+4%)
0.476 + 0.0396*
(+10%)
0.510 + 0.0335**
(+18%)
Adrenal glands
0.014 ±0.0019
0.014 ±0.0034
(0%)
0.014 + 0.0046
(0%)
0.015 + 0.0045
(+7%)
Testes
0.662 ± 0.086
0.762 ±0.174
(+15%)
0.477 + 0.203*
(-28%)
0.291 + 0.048**
(-56%)
Kidneys
0.731 ±0.083
0.814 ±0.085
(+11%)
0.838 + 0.102*
(+15%)
0.915 + 0.093**
(+25%)
Liver
3.283 ±0.319
3.394 ±0.431
(+3%)
3.578 + 0.465
(+9%)
3.829 + 0.372*
(+17%)
Female Absolute Organ Weights (g)
Brain
2.00 ±0.080
2.04±0.119
(+2%)
1.96 + 0.085
(-2%)
2.01+0.092
(+1%)
Adrenal glands
0.0774 ±0.01955
0.0833 + 0.01448
(+8%)
0.0786 + 0.01091
(+2%)
0.0820 + 0.01741
(+6%)
Ovaries
0.0966 ±0.03528
0.1223 + 0.03781
(+27%)
0.0837 + 0.016
(-13%)
0.1119 + 0.03584
(+15%)
Kidneys
2.20 ±0.277
2.23 + 0.230
(+1%)
2.18 + 0.267
(-1%)
2.18 + 0.247
(-1%)
Liver
8.77 ± 1.227
8.52 + 0.862
(-2.9%)
8.37+1.212
(-4.6%)
9.22+ 1.607
(+5.1%)
Necropsy body weight
263 ± 26.0
257 + 21.9
(-3%)
237+ 12.8f
(-10%)
245 + 36.6
("7%)
47
p-a, a, a-T etrachl orotoluene
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FINAL
September 2019
Table B-6. Absolute and Relative Organ Weights in Male and Female Rats Orally
Exposed to />-a,a,a-Tetrachlorotoluene for 90 Days3
Endpoint
Dose (mg/kg-d)b'c
0
1.25
12.5
25.0
Female Relative Organ Weights (% BW)
Brain
0.767 ± 0.073
0.800 ±0.083
(+4%)
0.830 ±0.034
(+8%)
0.835 ±0.109
(+9%)
Adrenal glands
0.030 ±0.0077
0.033 ±0.0057
(+10%)
0.033 ±0.0045
(+10%)
0.033 ±0.0047
(+10%)
Ovaries
0.037 ±0.014
0.048 ±0.014
(+30%)
0.035 ±0.007
(-5%)
0.046 ±0.012
(+24%)
Kidneys
0.837 ±0.082
0.870 ± 0.072
(+4%)
0.922 ±0.112
(+10%)
0.898 ±0.073
(+7%)
Liver
3.353 ±0.454
3.325 ±0.320
(-1%)
3.534 ±0.419
(+5%)
3.761 ±0.278
(+12%)
aLiao (1989a. 1989c).
bData are mean ± SD; n = 10/group, except n = 9 for adrenal gland weight in high-dose males (one lost at
necropsy).
°Value in parentheses is % change relative to control = ([treatment mean - control mean] + control mean) x 100.
* Significantly different from control (p < 0.05), as reported by the study authors.
**Significantly different from control (p < 0.01), as reported by the study authors,
f Statistical analysis not provided by study authors; significantly different from controls by unpaired /-test
(p < 0.05), as conducted fortius review.
BW = body weight; SD = standard deviation.
48
p-a, a, a-T etrachl orotoluene
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September 2019
Table B-7. Incidence of Selected Non-neoplastic Lesions in Male and Female Rats Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 90 Days3
Endpoint
Dose (mg/kg-d)b
0
1.25
12.5
25.0
Male
Epididymis
Aspermia
0/10
0/10
0/10
10/10** (100%)
Testis
Total tubular atrophy, aspermatogenesis:
0/10
0/10
7/10** (70%)
10/10** (100%)
Mild
0/10
0/10
2/10 (20%)
1/10 (10%)
Moderate
0/10
0/10
0/10
2/10 (20%)
Marked
0/10
0/10
5/10* (50%)
7/10** (70%)
Syncytial giant cells, tubules:
0/10
0/10
3/10 (30%)
0/10
Mild
0/10
0/10
1/10 (10%)
0/10
Moderate
0/10
0/10
1/10 (10%)
0/10
Marked
0/10
0/10
1/10 (10%)
0/10
Female
Liver
Altered foci, eosinophilic:
0/10
0/10
0/10
4/10* (40%)
Minimal
0/10
0/10
0/10
3/10 (30%)
Mild
0/10
0/10
0/10
1/10 (10%)
aLiao (1989a. 1989c).
bValues denote number of animals showing changes total number of animals examined (% incidence).
* Significantly different from control by Fisher's exact test (one-sided; p < 0.05), as conducted for this review.
**Significantly different from control by Fisher's exact test (one-sided; p < 0.01), as conducted for this review.
49
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September 2019
Table B-8. Tumor Incidence in ICR Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
Endpoint
Dose (HED) (mg/kg-d)b
0
0.21 (0.028)
0.54 (0.072)
1.3 (0.18)
3.3 (0.44)
8.2 (1.1)
Initial number of animals
30
30
30
26
31
31
Effective number of animals0
26
22
28
22
29
29
Average age (months) of affected animals
17.5
17.9
16.9
16.9
14.8
6.2
Occurrence of 50% mortality (months)
>18
>18
>18
>18
12.3
4.7
Number of animals with tumors ^ effective number of animals (% incidence)
Tumors types:
Malignant
Benign
Total
1/26 (4%)
1/26 (4%)
2/26 (8%)
4/22 (18%)
2/22 (9%)
6/22 (27%)
8/28* (30%)
2/28 (7%)
10/28* (36%)
10/22** (45%)
7/22* (32%)
17/22** (77%)
20/29** (69%)
7/29* (24%)
27/29** (93%)
16/29** (55%)
9/29* (31%)
25/29** (86%)
Forestomach:
Squamous cell carcinoma
Carcinoma in situ
Multiple papilloma
0/26f
0/26f
0/26
0/22
0/22
2/22 (9%)
0/28
0/28
4/28 (14%)
0/22
1/22 (5%)
5/22* (23%)
6/29* (21%)
4/29 (14%)
2/29 (7%)
7/29** (24%)
3/29 (10%)
1/29 (3%)
Glandular stomach carcinoma
0/26
1/22 (5%)
0/28
0/22
0/29
0/29
Lung:
Adenocarcinoma
Multiple adenoma
0/26^ f
l/26f (4%)
3/22 (14%)
2/22 (9%)
7/28* (23%)
1/28 (3%)
10/22** (45%)
6/22* (27%)
15/29** (52%)
10/29** (34%)
2/29 (7%)
17/29** (59%)
Malignant lymphoma
l/26f (4%)
0/22
1/28 (3%)
0/22
0/29
5/29 (17%)
Thymoma
0/26f
0/22
0/28
0/22
4/29 (14%)
8/29** (28%)
Skin tumor:
Squamous cell carcinoma
Spindle cell carcinoma
Sebaceous gland carcinoma
0/26f
0/26
0/26
0/22
0/22
0/22
0/28
0/28
0/28
0/22
1/22 (5%)
0/22
0/29
1/29 (3%)
1/29 (3%)
5/29* (21%)
0/29
0/29
50
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September 2019
Table B-8. Tumor Incidence in ICR Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
Endpoint
Dose (HED) (mg/kg-d)b
0
0.21 (0.028)
0.54 (0.072)
1.3 (0.18)
3.3 (0.44)
8.2 (1.1)
Other tumors:
Mammary adenocarcinoma
0/26
0/22
1/28 (3%)
0/22
0/29
1/29 (3%)
Ear canal squamous cell carcinoma
0/26
0/22
0/28
0/22
1/29 (3%)
0/29
Ovary glanulosa cell tumor
0/26
0/22
0/28
1/22 (5%)
0/29
0/29
Salivary gland adenocarcinoma
0/26
0/22
0/28
0/22
2/29 (7%)
0/29
aFukuda et at (1980): Fukuda et al. (1979).
bThe nominal treatment doses of 0, 3.2, 8.4, 21, 51 and 130 mg/kg were converted to daily doses averaged over the study duration of 18 months; calculated HEDs appear
in brackets.
°This number presumably represents number of animals available to develop tumors but was not defined in the study report.
dTest for trend only significant with top dose removed.
* Significantly different from control (p < 0.05) by two-tailed Fisher's exact test, as conducted for this review.
**Significantly different from controlp < 0.01) by two-tailed Fisher's exact test, as conducted for this review,
f Significant trend (p < 0.005) by Cochran-Armitage x2 test, as conducted for this review.
HED = human equivalent dose.
51
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September 2019
Table B-9. Weekly Body Weights, Food Consumption, and Water Intake in Male and
Female Albino Rats Exposed to />-a,a,a-Tetrachlorotoluene Vapor via
Inhalation for 30 Days3
Endpoint
Exposure Concentration (HECer) (mg/m3)b'c
0
3.98 (0.711)
18.9 (3.38)
94.5 (16.9)
Male Body Weights (g)
Week-1.0
161
159 (-1%)
159 (-1%)
159 (-1%)
Week 0.1
208
209 (+0.5%)
207 (-0.5%)
212 (+2%)
Week 1.0
264
264 (0%)
260 (-2%)
209 (-21%)
Week 2.0
312
313 (+0.3%)
307 (-2%)
196 (-37%)
Week 3.0
347
349 (+0.6%)
340 (-2%)
196 (-44%)
Week 4.0
375
377 (+0.5%)
364 (-3%)
196 (-48%)
Body-weight gain (Weeks 0.1-4)
167
168 (+1%)
158 (-6%)
-16** (-110%)
Male Cumulative Intakes (g/rat)
Food consumption
746
766 (+3%)
737 (-1%)
411** (-45%)
Water consumption
930
966 (+4%)
943 (+1%)
700* (-25%)
Female Body Weights (g)
Week-1.0
131
132 (+0.8%)
132 (+0.8%)
132 (+1%)
Week 0.1
160
159 (-0.6%)
158 (-1%)
160 (0%)
Week 1.0
183
184 (+0.5%)
184 (+0.5%)
156 (-15%)
Week 2.0
207
207 (0%)
208 (+0.5%)
161 (-22%)
Week 3.0
224
226 (+1%)
221 (-1%)
164 (-27%)
Week 4.0
238
234 (-2%)
236 (-0.8%)
154 (-35%)
Body-weight gain (Weeks 0.1-4)
78
75 (-4%)
78 (0%)
-6** (-108%)
Female Cumulative Intakes (g/rat)
Food consumption
543
540 (-1%)
537 (-1%)
357** (-34%)
Water consumption
851
876 (+3%)
813 (-5%)
700* (-18%)
aRose et at (1984).
bData are means (SD not reported); n = 10/group.
°Value in parentheses is % change relative to control = ([treatment mean - control mean] + control mean) x 100.
* Significantly different from control using the method of least significant differences (p < 0.05), as reported by the
study authors.
**Significantly different from control using the method of least significant differences (p < 0.01), as reported by
the study authors.
ER = extrarespiratory; HEC = human equivalent concentration; SD = standard deviation.
52
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September 2019
Table B-10. Select Day 24 Group Mean Hematology, Serum Chemistry, and Urinalysis
Results in Male and Female Albino Rats Exposed to />-a,a,a-Tetrachlorotoluene Vapor by
Inhalation for 30 Days3
Endpoint
Exposure Concentration (HECer) (mg/m3)b'c
0
3.98 (0.711)
18.9 (3.38)
94.5 (16.9)
Male
Hematology
Packed cell volume (%)
45 ± 1.1
47 ±2.4
(+4%)
47 ± 1.7
(+4%)
48 ±2.3*
(+7%)
Hb (g/dL)
15.2 ±0.47
15.6 ±0.49
(+3%)
16.5 ±0.35**
(+9%)
17.7 ±0.69**
(+16%)
Hct (%)
33.4 ±0.83
33.0 ±0.82
(0%)
35.5 ± 1.14**
(+6%)
36.6 ±0.91**
(+10%)
RBC (106/|iL)
7.3 ±0.44
7.3 ±0.75
(0%)
8.0 ±0.28*
(+10%)
9.0 ±0.40**
(+23%)
Total WBC (103/|iL)
9.0 ± 1.77
10.5 ±2.65
(+17%)
12.6 ±0.78
(+40%)
5.5 ±2.36*
(-39%)
Lymphocytes (107|iL)
6.84 ± 1.12
8.66 ±2.43
(+27%)
10.06 ± 1.32
(+47%)
3.53 ±2.0*
(-48%)
Total cells in bone marrow (103)
109 ±23.1
183 ±74.7
(+68%)
93 ±26.1
(-15%)
55 ±9.5*
(-50%)
Serum chemistry
Albumin (g/d)
3.7 ±0.08
3.6 ±0.15
(-3%)
3.5 ± 0.1*
(-5%)
3.5 ±0.09**
(-5%)
A:G
1.36 ± 0.11
1.23 ±0.14
(-10%)
1.09 ±0.06**
(-20%)
1.12 ±0.09**
(-18%)
ALT (mU/mL)
27 ± 10.9
19 ± 3.1
(-30%)
17 ±4.3*
(-37%)
17 ±3.3*
(-37%)
AST (mU/mL)
65 ±25
53 ±6.0
(-18%)
50 ±7.4
(-23%)
41 ±3.2**
(-37%)
Creatinine (mg/dL)
0.8 ±0.07
0.8 ±0.04
(0%)
0.7 ±0.05
(-13%)
0.6 ±0.04**
(-25%)
Calcium (mEq/L)
5.4 ± 0.18
5.6 ±0.08
(+3%)
5.5 ± 0.16
(+2%)
5.2 ±0.09*
(-4%)
Female
Hematology
Packed cell volume (%)
45 ± 1.7
45 ± 1.4
(0%)
44 ±0.8
(-2%)
45 ±2.5
(0%)
Hb (g/dL)
15.7 ±0.98
15.0 ±0.16
(-4%)
14.7 ±0.34
(-6%)
15.0 ±0.76
(-4%)
RBC (106/|iL)
7.6 ±0.32
7.6 ±0.22
(0%)
6.8 ±0.25*
("11%)
7.0 ±0.56*
(-8%)
Hct (%)
34.5 ± 1.23
33.4 ± 1.06
(-3%)
33.6 ±0.77
(-3%)
33.8 ± 1.52
(-2%)
Total WBC (103/|iL)
7.7 ± 1.23
8.8 ± 1.7
(+14%)
7.2 ±2.08
(0%)
3.0 ± 1.22*
(-61%)
53
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September 2019
Table B-10. Select Day 24 Group Mean Hematology, Serum Chemistry, and Urinalysis
Results in Male and Female Albino Rats Exposed to />-a,a,a-Tetrachlorotoluene Vapor by
Inhalation for 30 Days3
Endpoint
Exposure Concentration (HECer) (mg/m3)b'c
0
3.98 (0.711)
18.9 (3.38)
94.5 (16.9)
Lymphocytes (1057|iL)
6.84 ± 1.09
7.18± 1.57
(+5%)
5.94 ± 1.58
(-13%)
1.87 ±0.58**
(-73%)
Eosinophils (1057|iL)
0.12 ±0.106
0.08 ±0.087
(-33%)
0.05 ±0.074
(-58%)
0.00 ±0.000*
(-100%)
Total cells in bone marrow (103)
111 ± 38.8
81 ±44.2
(-27%)
119 ±50.7
(+7%)
34 ± 18.9**
(-69%)
Serum chemistry
Phosphorus (mEq/L)
4.2 ±0.29
3.9 ± 0.19
(-7%)
3.8 ±0.29
(-7%)
4.7 ±0.21**
(+12%)
Cholesterol (mg/dL)
64 ± 6.7
60 ±8.7
(-6%)
66 ± 5.0
(+10%)
51 ±4.7*
(-20%)
Urinalysis
Protein in urine (mg/dL)
28 ±26.8
0.0 ±0.0*
(-100%)
0.0 ±0.0*
(-100%)
14 ± 19.5*
(-50%)
aRose et at (1984).
bData are mean ± SD; n = 10/group.
°Value in parentheses is % change relative to control = ([treatment mean - control mean] + control mean) x 100.
* Significantly different from control using Williams' test (p < 0.05), as reported by the study authors.
**Significantly different from control using Williams' test (p < 0.01), as reported by the study authors.
A:G = albumin:globulin ratio; ALT = alanine transaminase; AST = aspartate aminotransferase;
ER = extrarespiratory; Hb = hemoglobin; Hct = hematocrit; HEC = human equivalent concentration; RBC = red
blood cell; SD = standard deviation; WBC = white blood cell.
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September 2019
Table B-ll. Group Mean Absolute Organ Weights in Male and Female Albino Rats
Exposed to/>-a,a,a-Tetrachlorotoluene Vapor by Inhalation for 30 Days3
Endpoint
Organ Weights (g)
Exposure Concentration (HECer) (mg/m3)
0
3.98 (0.711)
18.9 (3.38)
94.5 (16.9)
Maleb'c
Brain, adjustedd
1.82
1.82 (0%)
1.85 (+2%)
1.90 (+4%)
Pituitary
0.014
0.012 (-12%)
0.013 (-7%)
0.010** (-29%)
Heart
1.1
1.2 (+9%)
1.1 (0%)
0.8** (-27%)
Lungs6
0.91
0.93 (+2%)
0.91 (0%)
0.88 (-3%)
Liver
16.7
16.2 (-3%)
15.7 (-6%)
9.7 (-42%)f
Liver, adjustedd
14.2
13.7 (-4%)
14.2 (0%)
17.4* (+23%)
Spleen
1.0
1.0 (0%)
0.9 (-10%)
0.4** (-60%)
Thymus
0.6
0.6 (0%)
0.5* (-17%)
0.1** (-83%)
Kidney, adjustedd
2.5
2.5 (0%)
2.6 (+4%)
2.9 (+16%)
Thyroid
0.024
0.024 (0%)
0.026 (+8%)
0.017** (-29%)
Adrenals
0.066
0.064 (-3%)
0.069 (+4%)
0.070 (+6%)
Gonads
4.1
4.2 (+2%)
4.2 (+2%)
1.5** (-63%)
Necropsy body weight
371
371 (0%)
355 (-4%)
190 (-49%)f
Femaleb'c
Brain
1.70
1.75 (+3%)
1.71 (+1%)
1.61* (-5%)
Pituitary, adjustedd
0.013
0.012 (-8%)
0.012 (-8%)
0.016 (+29%)
Heart
0.9
0.9 (0%)
1.0 (+11%)
0.7 (-23%)
Lungs
1.2
1.1 (-8%)
1.2 (0%)
1.2 (0%)
Lungs, adjusted4 e
0.71
0.69 (-3%)
0.71 (0%)
0.99** (+39%)
Liver
10.1
9.6 (-4%)
9.9 (-2%)
7.0 (-31%)f
Liver, adjusted4
8.7
8.3 (-5%)
8.5 (-2%)
11.0* (+26%)
Spleen, adjusted4 e
0.5
0.5 (0%)
0.4 (-20%)
0.4 (-20%)
Thymus, adjusted4 e
0.3
0.3 (0%)
0.3 (0%)
0.3 (0%)
Uterus
0.5
0.6 (+20%)
0.6 (+20%)
0.2** (-60%)
Kidney, adjusted4
1.6
1.7 (+6%)
1.7 (+6%)
1.9 (+19%)
Thyroid
0.021
0.017 (-19%)
0.022 (+5%)
0.017 (-19%)
55
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September 2019
Table B-ll. Group Mean Absolute Organ Weights in Male and Female Albino Rats
Exposed to/>-a,a,a-Tetrachlorotoluene Vapor by Inhalation for 30 Days3
Organ Weights (g)
Exposure Concentration (HECer) (mg/m3)
Endpoint
0
3.98 (0.711)
18.9 (3.38)
94.5 (16.9)
Adrenals
0.088
0.088 (0%)
0.082 (-7%)
0.092 (+5%)
Gonads
102
100 (-2%)
96 (-6%)
84 (-18%)
Necropsy body weight
235
233 (-1%)
234 (-0.4%)
139 (-41%)f
aRose et at (1984).
bData are means (SD not reported); n = 10/group.
°Value in parentheses is % change relative to control = ([treatment mean - control mean] control mean) x 100.
'Organ weights were "adjusted for final body weights where appropriate," as reported by the study authors (no
further details were provided).
eData were log-transformed for statistical analysis, as reported by the study authors.
Statistical analysis was not provided by study authors, and insufficient data were provided to perform statistical
analysis for this review.
* Significantly different from control using Williams' test (p < 0.05), as reported by the study authors.
**Significantly different from control using Williams' test (p < 0.01), as reported by the study authors.
ER = extrarespiratory; HEC = human equivalent concentration; SD = standard deviation.
56
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September 2019
Table B-12. Incidence of Macroscopic Observations in Male and Female Albino Rats
Exposed to/>-a,a,a-Tetrachlorotoluene Vapor by Inhalation for 30 Days3
Endpoint
Exposure Concentration (HECer) (mg/m3)
0
3.98 (0.711)
18.9 (3.38)
94.5 (16.9)
Maleb
Thymus:
Small
Congested
0/10
0/10
0/10
0/10
0/10
0/10
8/9** (89%)
1/9(11%)
Adipose tissue:
Minimal
0/10
0/10
0/10
7/9** (78%)
Testes:
Small
0/10
0/10
0/10
9/9"f (100%)
Skin:
Alopecia
0/10
0/10
0/10
4/9* (44%)
Fur:
Stained
Badly groomed
0/10
0/10
0/10
0/10
1/10 (10%)
0/10
1/9(11%)
4/9* (44%)
Femaleb
Thymus:
Small
Congested
0/10
0/10
0/10
0/10
0/10
0/10
10/10f (100%)
0/10
Adipose tissue:
Minimal
0/10
0/10
0/10
9/10** (90%)
Skin:
Alopecia
0/10
0/10
0/10
3/10 (30%)
Fur:
Stained
Badly groomed
0/10
0/10
0/10
0/10
0/10
0/10
4/10 (40%)
0/10
aRose et at (1984).
bValues denote number of animals showing changes total number of animals examined (% incidence).
* Significantly different from control by Fisher's exact test (two-tailed p < 0.05) conducted for this review.
**Significantly different from control by Fisher's exact test (two-tailedp < 0.01) conducted for this review,
f Significantly different from control by Fisher's exact test (two-tailedp < 0.001) conducted for this review.
ER = extrarespiratory; HEC = human equivalent concentration.
57
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September 2019
Table B-13. Incidence of Selected Non-neoplastic Lesions in Extrarespiratory Tissues in Albino Rats Exposed to
/>-a,a,a-Tetrachlorotoluene Vapor by Inhalation for 30 Days3
Exposure Concentration (HECer) (mg/m3)b
Endpoint
0
3.98 (0.711)
18.9 (3.38)
94.5 (16.9)
Male
Spleen:
Decreased cellularity of white pulp
0/5
NA
NA
4/6* (67%)
Decreased cellularity of red pulp
0/5
NA
NA
5/6* (83%)
Thymus:
Marked involution
0/5
NA
NA
4/6* (67%)
Severe involution
0/5
NA
NA
1/6 (17%)
Testes:
Marked tubular atrophy
0/5
NA
NA
4/6* (67%)
Severe tubular atrophy
0/5
NA
NA
1/6 (17%)
Arrest of spermatogenesis
0/5
NA
NA
1/6 (17%)
Female0
Spleen:
Decreased cellularity of white pulp
0/5
NA
NA
3/5 (60%)
Decreased cellularity of red pulp
0/5
NA
NA
5/5* (100%)
Thymus:
Moderate involution
0/5
NA
NA
2/5 (20%)
Marked involution
0/5
NA
NA
2/5 (20%)
Severe involution
0/5
NA
NA
0/5
Uterus:
Reduction in endometrial width
0/5
NA
NA
4/5* (80%)
aRose et at (1984).
bValues denote number of animals showing changes total number of animals examined (% incidence).
°One female rat in the high-dose group was found dead immediately prior to postmortem examination; tissues from this animal were not examined microscopically.
* Significantly different from control by Fisher's exact test (one-sided p < 0.05), as conducted for this review.
ER = extrarespiratory; HEC = human equivalent concentration; NA = not applicable.
58
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September 2019
Table B-14. Incidence of Selected Non-neoplastic Lesions in the Upper Respiratory Tract in Albino Rats Exposed to
/>-a,a,a-Tetrachlorotoluene Vapor by Inhalation for 30 Days3
Exposure Concentration (HECet) (mg/m3)b
Endpoint
0
3.98 (0.142 [M], 0.107 [F])
18.9 (0.675 [M], 0.506 [F])
94.5 (2.53 [M], 2.03 [F])
Male0
Nasal passages:
Focal atrophy of olfactory epithelium
0/5
1/5 (20%)
3/5 (60%)
0/6
Severe atrophy of olfactory epithelium
0/5
0/5
1/5 (20%)
6/6* (100%)
Extensive squamous keratinizing epithelial
0/5
0/5
0/5
4/6* (67%)
metaplasia
Inflammatory exudate in chamber
0/5
0/5
0/5
6/6* (100%)
Larynx:
Epithelial hyperplasia in ventrolateral region
0/5
0/5
4/5* (80%)
0/6
Squamous keratinizing epithelial metaplasia in:
Ventrolateral region
0/5
0/5
0/5
6/6* (100%)
Tracheo-larangeal junction
0/5
0/5
0/5
5/6* (83%)
Keratinizing epithelial hyperplasia over arytenoid
0/5
0/5
0/5
6/6* (100%)
projections
Pharynx:
Squamous keratinizing epithelial metaplasia
0/5
NA
NA
2/6 (33%)
Female0'd
Nasal passages:
Focal atrophy of olfactory epithelium
0/5
0/5
5/5* (100%)
0/5
Severe atrophy of olfactory epithelium
0/5
0/5
0/5
5/5* (100%)
Extensive squamous keratinizing epithelial
0/5
0/5
0/5
5/5* (100%)
metaplasia
Inflammatory exudate in chambers
0/5
0/5
0/5
5/5* (100%)
Larynx:
Epithelial hyperplasia in ventrolateral region
0/5
0/5
1/5 (20%)
0/5
Squamous keratinizing epithelial metaplasia in:
Ventrolateral region
0/5
0/5
0/5
5/5* (100%)
Tracheo-larangeal junction
0/5
0/5
0/5
4/5* (80%)
Keratinizing epithelial hyperplasia over arytenoid
0/5
1/5 (20%)
2/5 (40%)
5/5* (100%)
projections
59
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September 2019
Table B-14. Incidence of Selected Non-neoplastic Lesions in the Upper Respiratory Tract in Albino Rats Exposed to
/>-a,a,a-Tetrachlorotoluene Vapor by Inhalation for 30 Days3
Endpoint
Exposure Concentration (HECet) (mg/m3)b
0
3.98 (0.142 [M], 0.107 [F])
18.9 (0.675 [M], 0.506 [F])
94.5 (2.53 [M], 2.03 [F])
Pharynx:
Squamous keratinizing epithelial metaplasia
0/5
NA
NA
3/5 (60%)
aRose et at (1984).
bHECET values calculated using TWA body weights for each dose group in the study.
°Values denote number of animals showing changes total number of animals examined (% incidence).
^ne female rat in the high-dose group was found dead immediately prior to postmortem examination; tissues from this animal were not examined microscopically.
* Significantly different from control by Fisher's exact test (one-sided p < 0.05), as conducted for this review.
ET = extrathoracic; F = female(s); HEC = human equivalent concentration; M = male(s); NA = not applicable; TWA = time-weighted average.
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Table B-15. Incidence of Selected Non-neoplastic Lesions in the Lower Respiratory Tract in Albino Rats Exposed to
/>-a,a,a-Tetrachlorotoluene Vapor by Inhalation for 30 Days3
Male
Exposure Concentration (HECib) (mg/m3)b'c
Endpoint
0
3.98 (1.49)
18.9 (6.75)
94.5 (23.6)
Trachea:
Minimal epithelial hyperplasia
0/5
0/5
4/5* (80%)
0/6
Moderate epithelial hyperplasia
0/5
0/5
1/5 (20%)
1/6 (17%)
Extensive epithelial hyperplasia
0/5
0/5
0/5
1/6 (17%)
Regeneration of tracheal epithelium
0/5
0/5
0/5
2/6 (33%)
Severe epithelial ulceration
0/5
0/5
0/5
3/6 (50%)
Tracheal carina:
Severe epithelial ulceration
0/5
NA
NA
6/6* (100%)
Marked inflammatory cell exudate and mucus in lumen
0/5
NA
NA
1/6 (17%)
Bronchioles:
Severe ulceration of bronchiolar epithelium
0/5
NA
NA
6/6* (100%)
Focal regeneration of bronchiolar epithelium
0/5
NA
NA
6/6* (100%)
Femaled
Exposure Concentration (HECib) (mg/m3)b'c
Endpoint
0
3.98 (0.995)
18.9 (4.73)
94.5 (20.3)
Trachea:
Minimal epithelial hyperplasia
0/5
0/5
2/5 (40%)
0/5
Moderate epithelial hyperplasia
0/5
0/5
1/5 (20%)
1/5 (20%)
Extensive epithelial hyperplasia
0/5
0/5
0/5
0/5
Regeneration of tracheal epithelium
0/5
0/5
0/5
2/5 (40%)
Severe epithelial ulceration
0/5
0/5
0/5
2/5 (20%)
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Table B-15. Incidence of Selected Non-neoplastic Lesions in the Lower Respiratory Tract in Albino Rats Exposed to
/>-a,a,a-Tetrachlorotoluene Vapor by Inhalation for 30 Days3
Tracheal carina:
Severe epithelial ulceration
0/5
NA
NA
5/5* (100%)
Inflammatory cell exudate in lumen
0/5
NA
NA
4/5* (80%)
Bronchioles:
Severe ulceration of bronchiolar epithelium
Focal regeneration of bronchiolar epithelium
0/5
0/5
NA
NA
NA
NA
5/5* (100%)
4/5* (80%)
aRose et at (1984).
bHECTB values calculated using TWA body weights for each dose group in the study.
°Values denote number of animals showing changes total number of animals examined (% incidence).
^ne female rat in the high-dose group was found dead immediately prior to postmortem examination; tissues from this animal were not examined microscopically.
* Significantly different from control by Fisher's exact test (one-sided p < 0.05), as conducted for this review.
F = female(s); HEC = human equivalent concentration; M = male(s); NA = not applicable; TB = tracheobronchial; TWA = time-weighted average.
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Table B-16. Group Mean Body Weights and Mean Body-Weight Changes in Pregnant
Female Rats Exposed by Inhalation to />-a,a,a-Tetrachlorotoluene Vapor on GDs 6-19a
Time point
Exposure Concentration (HECer) (mg/m3)b'c
II
o
4.1 (1.0) (n = 19)
10.4 (2.60) (n = 21)
25.2 (6.30) (n = 22)
GD
Body Weight (g)
6
236.1 ± 17.4
238.0 ± 13.1 (+1%)
236.6 ± 16.1 (-1%)
235.2 ± 13.1 (-1%)
10
258.9 ± 18.7
259.0 ± 14.7 (0%)
257.9 ± 17.4 (0%)
250.0 ± 14.7 (-3%)
14
284.7 ± 19.7
285.6 ± 16.1 (0%)
284.8 ± 19.7 (0%)
269.9 ± 15.1* (-5%)
17
314.2 ± 21.0
316.5 ± 18.7 (+1%)
314.7 ±22.0 (-1%)
290.9 ± 17.5** (-8%)
20
354.3 ±24.2
356.3 ±22.1 (+1%)
353.1 ±27.1 (-1%)
321.2 ±20.5** (-9%)
GD
Body-Weight Change (g)
6-10
22.9 ±4.7
21 ± 4.4 (-8%)
21.3 ±4.4 (-7%)
14.8 ± 5.6** (-35%)
6-14
48.7 ±6.2
47.6 ±6.1 (-2%)
48.1 ±6.6 (-1%)
34.7 ± 7.5** (-29%)
6-17
78.2 ±8.3
78.5 ± 9.3 (0%)
78.0 ± 8.7 (0%)
55.6 ± 11.9** (-29%)
6-20
118.3 ± 11.3
118.3 ± 12.9(0%)
116.5 ± 15.1 (-2%)
86.0 ± 17.4** (-27%)
aEdwards et al. (1985).
bData are mean ± SD (SD calculated for this review from individual body-weight data).
°Value in parentheses is % change relative to control = ([treatment mean - control mean] control mean) x 100.
* Significantly different from control (p < 0.01) by unpaired Student's t-test (two-tailed), as conducted for this
review.
**Significantly different from control (p < 0.001) by unpaired Student's /-test (two-tailed), as conducted for this
review.
ER = extrarespiratory; GD = gestation day; HEC = human equivalent concentration; SD = standard deviation.
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Table B-17. Group Mean Litter Data from Pregnant Female Rats Exposed by Inhalation
to />-a,a,a-Tetrachlorotoluene Vapor on GDs 6-19a
Endpoint
Exposure Concentration (HECer) (mg/m3)b'c
0
4.1 (1.0)
10.4 (2.60)
25.2 (6.30)
Number of animals with live young
19
19
21
22
Corpora lutea
14.8
14.2 (-4%)
13.9 (-6%)
13.8 (-7%)
Implants
12.5
13.0 (+4%)
12.7 (+2%)
11.6 (-7%)
Live young
11.5
12.1 (+5%)
12.0 (+4%)
11.2 (-3%)
Embryonic deaths:
Early
Late
Total
1.0
0.0
l.Of
0.8 (-20%)
0.2
0.9 (-10%)
0.6 (-40%)
0.0
0.6 (-40%)
0.4 (-60%)
0.0
0.4* (-60%)
Preimplant loss (%)d
13.1
7.8 (-40%)
10.0 (-24%)
16.2 (+24%)
Postimplant loss (%)e
7.8f
7.0 (-10%)
4.7 (-40%)
3.3* (-58%)
Litter weight (g)
37.94
39.43 (+4%)
38.44 (+1%)
34.24 (-10%)
Mean fetal weight (g)
3.30fft
3.27 (-1%)
3.21 (-3%)
3.05** (-8%)
aEdwards et al. (1985).
bData are means of litter values (SD not reported).
°Value in parentheses is % change relative to control = ([treatment mean - control mean] + control mean) x 100.
d([Number of corpora lutea - number of implantations] + [number of corpora lutea]) x 100.
"([Number of implantations - number of live young] + [number of implantations]) x 100.
*Intergroup differences from control statistically significant in the absence of significant "H" statistic (p < 0.05), as
reported by the study authors.
**Statistically significant intergroup differences from control using the Kruskal-Wallis test (p < 0.01), as reported
by the study authors.
f Significant trend using Jonckheere "J" statistic (p < 0.05), as reported by the study authors,
f f Significant trend using Jonckheere "J" statistic (p < 0.01), as reported by the study authors.
{Significant difference among groups using the Kruskal-Wallis "H" statistic (p < 0.01), as reported by the study
authors.
ER = extrarespiratory; GD = gestation day; HEC = human equivalent concentration; SD = standard deviation.
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Table B-18. Incidence of Skeletal Variants in Fetuses from Female Rats Exposed by
Inhalation to />-a,a,a-Tetrachlorotoluene Vapor on GDs 6-19a
Endpoint
Exposure Concentration (HECer) (mg/m3)
0
4.1 (1.0)
10.4 (2.60)
25.2 (6.30)
Number of fetuses examined
107
111
123
121
Sternebrae
Normal
29ft (27.1%)
13 (12.2%)
17 (13.7%)
4* (3.1%)
Unossified
55f{ (51.8%)
74 (67%)
80 (65.6%)
105** (84.6%)
Reduced
42 (38.4%)
57 (51.1%)
56 (43.4%)
50 (44.1%)
Total variant
78ft (72.9%)
98 (87.8%)
106 (86.3%)
117** (96.9%)
aEdwards et al. (1985).
* Statistically significant intergroup differences from control using the Kruskal-Wallis test (p < 0.01), as reported by
the study authors using the litter as the basic sampling unit.
**Statistically significant intergroup differences from control using the Kruskal-Wallis test (p < 0.001), as reported
by the study authors using the litter as the basic sampling unit.
f Significant trend using Jonckheere "J" statistic (p < 0.001), as reported by the study authors using the litter as the
basic sampling unit.
{Significant difference among groups using the Kruskal-Wallis "H" statistic (p < 0.01), as reported by the study
authors using the litter as the basic sampling unit.
ER = extrarespiratory; GD = gestation day; HEC = human equivalent concentration.
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APPENDIX C. BENCHMARK DOSE MODELING RESULTS
MODELING PROCEDURE
Dichotomous Noncancer Data
The benchmark dose (BMD) modeling of dichotomous data is conducted with the
U. S. EPA's Benchmark Dose Software (BMDS, Version 2.6 was used for this document). For
these data, the Gamma, Logistic, Log-Logistic, Log-Probit, Multistage, Probit, and Weibull
dichotomous models available within the software are fit using a benchmark response (BMR) of
10% extra risk. Alternative BMRs may also be used where appropriate, as outlined in the
Benchmark Dose Technical Guidance (U.S. EPA. 2012b). In general, the BMR should be near
the low end of the observable range of increased risk in the study. BMRs that are too low can
result in widely disparate benchmark dose lower confidence limit (BMDL) estimates from
different models (high model-dependence). Adequacy of model fit is judged based on the
X2 goodness-of-fit /;-value (p > 0.1), magnitude of scaled residuals (absolute value < 2.0), and
visual inspection of the model fit. Among all models providing adequate fit, the BMDL from the
model with the lowest Akaike's information criterion (AIC) is selected as a potential point of
departure (POD), if the BMDLs are sufficiently close (less than approximately threefold); if the
BMDLs are not sufficiently close (greater than approximately threefold), model dependence is
indicated, and the model with the lowest reliable BMDL is selected.
Nested Dichotomous Data
The BMD modeling of nested dichotomous data from a developmental toxicity study is
conducted using the NLogistic model within the BMDS (Version 2.6). This model requires the
individual animal data showing the number of offspring experiencing the effect in question per
exposed dam in each dose group. Modeling of developmental endpoints uses a BMR of
5% extra risk (U.S. EPA 2018b). The model is run with and without an exposure-independent
litter-specific covariate (the theta [9] coefficients in the models), meant to account for intralitter
similarity due to the condition of the dam prior to treatment (U.S. EPA. 2018b). The model is
also run with and without intralitter correlations (the phi [O] coefficients in the models), meant
to account for similarity of responses to treatment among pups in the same litter (U. S. EPA.
2018b). The adequacy of model fit is judged based on the %2 goodness-of-fit /rvalue (p > 0.1),
magnitude of scaled residuals (absolute value < 2.0), and visual inspection of the model fit. A
decision to include the litter-specific covariate and/or intralitter correlation in the final model is
based on whether the 9 or O coefficients are estimated by BMDS to be nonzero, and if the model
fit is improved (e.g., per AIC or scaled residual comparison) when the litter-specific covariate
and/or intralitter correlation are included.
Cancer Data
The model-fitting procedure for dichotomous cancer incidence is as follows. The
Multistage cancer model in the U.S. EPA's BMDS (Version 2.6) is fit to the incidence data using
the extra risk option. The Multistage cancer model is run for all polynomial degrees up to n - 1
(where n is the number of dose groups including control). An adequate model fit is judged by
three criteria: (1) goodness-of-fit/>-value (p < 0.1), (2) visual inspection of the dose-response
curve, and (3) scaled residual at the data point (except the control) closest to the predefined BMR
(absolute value < 2.0). Among all the models providing adequate fit to the data, the BMDL for
the model with the lowest AIC is selected as the POD. In accordance with U.S. EPA (2012b)
and U.S. EPA (2005) guidance, BMD and BMDL values associated with an extra risk of 10%
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are calculated, which should be within the observable range of increased risk in a cancer
bioassay. The best fitting model (i.e., the polydegrees) is identified based on the process used for
noncancer data mentioned above. Modeling is performed for each individual tumor type with at
least a statistically significant trend. Where applicable, the MSCombo model is used to
evaluate the combined cancer risk of multiple tumor types. MS Combo is run using the
incidence data for the individual tumor types and the polydegrees from the best fitting model
identified in the model runs for the individual tumor types.
Continuous Data
BMD modeling of continuous data is conducted with U.S. EPA's BMDS (Version 2.6) as
well. All continuous models available within the software (Exponential, Hill, Linear,
Polynomial, and Power models) are fit using a standard reporting BMR of 1 standard
deviation (SD) relative risk. Alternate BMRs may also be used (e.g., BMR = 10% relative
deviation [RD] for body weight based on a biologically significant weight loss of 10%), as
outlined in the Benchmark Dose Technical Guidance (U.S. EPA. 2012b). In general, the BMR
should be near the low end of the observable range of increased risk in the study. BMRs that are
too low can result in widely disparate BMDL estimates from different models (high model
dependence). An adequate fit is judged based on the %2 goodness-of-fit^-value (p > 0.1),
magnitude of the scaled residuals near the BMR (absolute value < 2.0), and visual inspection of
the model fit. In addition to these three criteria forjudging adequacy of model fit, a
determination is made as to whether the variance across dose groups is homogeneous. If a
homogeneous variance model is deemed appropriate based on the statistical test provided by
BMDS (i.e., Test 2), the final BMD results are estimated from a homogeneous variance model.
If the test for homogeneity of variance is rejected (/;-value < 0.1), the model is run again while
modeling the variance as a power function of the mean to account for this nonhomogeneous
variance. If this nonhomogeneous variance model does not adequately fit the data (i.e., Test 3;
/;-value < 0.1), the data set is considered unsuitable for BMD modeling. Among all models
providing adequate fit, the lowest BMDL is selected if the BMDL estimates from different
models vary more than approximately threefold (indicating model dependence); otherwise, the
BMDL from the model with the lowest AIC is selected as a potential POD from which to derive
the reference value.
Dropping the High Dose
In the absence of a mechanistic understanding of the biological response to a toxic agent,
data from exposures much higher than the study lowest-observed-adverse-effect level (LOAEL)
do not provide reliable information regarding the shape of the response at low doses. Such
exposures, however, can have a strong effect on the shape of the fitted model in the low-dose
region of the dose-response curve. Thus, if lack of fit is due to characteristics of the
dose-response data for high doses, then the Benchmark Dose Technical Guidance document
allows for data to be adjusted by eliminating the high-dose group (U.S. HP A. 2012b). Because
the focus of BMD analysis is on the low-dose regions of the response curve, elimination of the
high-dose group may be reasonable for certain data sets.
BMD Modeling to Identify Potential PODs for Derivation of a Provisional Reference Dose
The most sensitive endpoints showing treatment-related changes in the principal study of
rats administered/>-a,a,a-tetrach 1 orotoluene by gavage daily for 90 days (l.iao. 1989a. c) were
reduced male body weights and absolute and relative testis weights, increased incidences of
testicular tubular atrophy and aspermatogenesis, and decreased lymphocyte counts in both males
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and females (see Tables B-4 to B-7 in Appendix B). Data sets for these endpoints were selected
to determine potential PODs for the provisional reference dose (p-RfD) using BMD analysis.
Data for these endpoints were fit to all available models for continuous or dichotomous data, as
appropriate. Summaries of modeling approaches and results (see Tables C-l to C-7) are
described below.
Decreased Terminal Body Weight in Male Sprague-Dawley (S-D) Rats Exposed Daily to
p-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
The procedure outlined above for continuous data was applied to the data for decreased
body weight in male rats exposed daily to /;-a,a,a-tetrachlorotoluene by gavage for 90 days
(Liao. 1989a. c). The constant variance model provided an adequate fit (p-value > 0.1) to the
variance data, and with that model applied, all the tested models provided adequate fit to the
means (see Table C-l). BMDLs for these models differed by more than approximately threefold,
so the model with the lowest BMDL was selected (Exponential Model 5). Figure C-l shows the
fit of the Exponential Model 5 to the data. Based on human equivalent doses (HEDs), the
BMD io and BMDLio were 3.11 and0.351 mg/kg-day, respectively.
Table C-l. BMD Modeling Results for Decreased Terminal Body Weight in Male S-D Rats
Exposed to />-a,a,a-Tetrachlorotoluene by Gavage for 90 Days3
Model
Variance
/>-Valucb
Means
/>-Valucb
Scaled Residual at
Dose Nearest BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
BMR = 10% RD change from control
Exponential (Model 2)°
0.21
0.64
-0.59
350.75
4.31
3.13
Exponential (Model 3)°
0.21
0.64
-0.59
350.75
4.31
3.13
Exponential (Model 4)°
0.21
0.65
0.12
352.05
3.11
0.549
Exponential (Model 5)c'd
0.21
0.65
0.12
352.05
3.11
0.351
Hillc
0.21
0.69
0.16
352.01
2.95
NDr
Lineal
0.21
0.59
-0.68
350.91
4.45
3.32
Polynomial (2-degree)6
0.21
0.59
-0.68
350.91
4.45
3.32
Polynomial (3-degree)6
0.21
0.59
-0.68
350.91
4.45
3.32
Power0
0.21
0.59
-0.68
350.91
4.45
3.32
aLiao (1989a. 1989c).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Tower restricted to >1.
dSelected model.
"Coefficients restricted to be negative.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose
associated with the selected BMR); BMDL = 95% lower confidence limit on the BMD (subscripts denote BMR:
i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose; NDr =
not determined; RD = relative deviation; S-D = Sprague-Dawley.
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Exponential 5 Model, with BMR of 0.1 Rel. Dev. for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
15:30 08/23 2018
Figure C-l. Fit of Exponential (Model 5) to Data for Decreased Terminal Body Weight in
Male S-D Rats Exposed Daily to »-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao,
1989a. c) (BMR = 10% RD)
BMD Model Output for Figure C-l:
Exponential Model. (Version: 1.11; Date: 03/14/2017)
Input Data File: E:/exp_bodyweight_Exp-ConstantVariance-BMR10-Down.(d)
Gnuplot Plotting File:
Thu Aug 23 15:30:31 2018
BMDS Model Run
The form of the response function by Model:
Model 2
Model 3
Model 4
Model 5
Y[dose]
Y[dose]
Y[dose]
Y[dose]
a * expfsign * b * dose}
a * expfsign * (b * dose)Ad}
a * [c-(c-l) * exp{-b *
a * [c-(c-l) * exp{-(b
Note: Y[dose] is the median response for exposure
sign = +1 for increasing trend in data;
sign = -1 for decreasing trend.
dose}]
* dose)Ad}]
dose;
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Model 2 is nested within Models 3 and 4.
Model 3 is nested within Model 5.
Model 4 is nested within Model 5.
Dependent variable = Mean
Independent variable = Dose
Data are assumed to be distributed: normally
Variance Model: exp(lnalpha +rho *ln(Y[dose]))
rho is set to 0.
A constant variance model is fit.
Total number of dose groups = 4
Total number of records with missing values = 0
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
MLE solution provided: Exact
Initial Parameter Values
Variable Model 5
lnalpha 7.59612
rho 0 Specified
a 570.15
b 0.279342
c 0.766716
d 1
Parameter Estimates
Variable Model 5 Std. Err.
lnalpha 7.60126 447.373
a 539.164 11.4226
b 0.268311 0.343703
c 0.82328 0.0973331
d 1 NA
Table of Stats From Input Data
Dose N Obs Mean Obs Std Dev
0 10 543 38.8
0.342 10 526 64
3.38 10 484 45.1
6.7 10 459 34.8
Estimated Values of Interest
Dose Est Mean Est Std Scaled Residual
0 539.2 44.73 0.2712
0.342 530.8 44.73 -0.3401
3.38 482.4 44.73 0.1163
6.7 459.7 44.73 -0.04734
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Other models for which likelihoods are calculated:
Model A1:
Model A2:
Model A3:
Model R:
Yij
= Mu(i) + e(i j )
Var{e(ij)}
= Sigma^2
Yij
= Mu(i) + e(i j )
Var{e(ij)}
= Sigma(i)^2
Yij
= Mu(i) + e(i j)
Var{e(ij)}
= exp(lalpha + log(mean(i)) * rho)
Yij
= Mu + e(i)
Var{e(ij)}
= Sigma^2
Model
A1
A2
A3
R
5
Likelihoods of Interest
Log (likelihood) DF
-171.9224 5
-169.6508 8
-171.9224 5
-180.7635 2
-172.0252 4
AIC
353.8448
355.3016
353.8448
365.5271
352.0503
Additive constant for all log-likelihoods = -36.76. This constant added to the
above values gives the log-likelihood including the term that does not
depend on the model parameters.
Test
1:
Test
2 :
Test
3:
Explanation of Tests
Does response and/or variances differ among Dose levels? (A2 vs. R)
Are Variances Homogeneous? (A2 vs. Al)
Are variances adeguately modeled? (A2 vs. A3)
Test 7a: Does Model 5 fit the data? (A3 vs 5)
Test
Test 1
Test 2
Test 3
Test 7a
Tests of Interest
-2*log(Likelihood Ratio)
22.23
4 .543
4 .543
0.2055
D. F.
6
3
3
1
p-value
0. 001102
0.2085
0.2085
0.6503
The p-value for Test 1 is less than .05. There appears to be a
difference between response and/or variances among the dose
levels, it seems appropriate to model the data.
The p-value for Test 2 is greater than .1. A homogeneous
variance model appears to be appropriate here.
The p-value for Test 3 is greater than .1. The modeled
variance appears to be appropriate here.
The p-value for Test 7a is greater than .1. Model 5 seems
to adeguately describe the data.
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Benchmark Dose Computations:
Specified Effect = 0.100000
Risk Type = Relative deviation
Confidence Level = 0.950000
BMD
3.10984
BMDL
0.351213
BMDU
67000
Decreased Absolute Testis Weight in Male S-D Rats Exposed Daily to
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
The procedure outlined above for continuous data was applied to the data for decreased
absolute testis weight in male rats exposed daily to/;-a,a,a-tetrachlorotoluene by gavage for
90 days (Liao. 1989a. c). The data were not amenable to BMD modeling because neither the
constant nor nonconstant variance model provided adequate fit to the variance data
(see Table C-2). In an attempt to obtain an adequate fit, the highest dose was dropped because
there was a significant difference at the mid dose. After dropping the highest dose, the variance
data still were not adequately fit by either the constant or nonconstant variance models. No
model was selected. The linear model is shown in Table C-2 to demonstrate the lack of fit to the
variance data.
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Table C-2. BMD Modeling Results for Decreased Absolute Testis Weight in Male S-D Rats
Exposed to />-a,a,a-Tetrachlorotoluene by Gavage for 90 Days
a
Variance
Means
Scaled Residual at
BMDisd (HED)
BMDLisd (HED)
Model
/>-Valucb
/>-Valucb
Dose Nearest BMD
AIC
(mg/kg-d)
(mg/kg-d)
All Doses
Constant variance
Lineal
<0.0001
0.15
1.39
7.38
1.72
1.37
Nonconstant variance
Lineal
<0.0001
0.24
-1.06
1.47
2.66
1.87
Highest Dose Dropped
Constant variance
Lineal
0.04
0.13
1.1
14.68
1.67
1.20
Nonconstant variance
Lineal
0.05
0.13
1.33
14.24
1.42
0.94
aLiao (1989a. 1989c).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be negative.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose
associated with the selected BMR); BMDL = 95% lower confidence limit on the BMD (subscripts denote BMR:
i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose;
S-D = Sprague-Dawley; SD = standard deviation.
Decreased Relative Testis Weight in Male S-D Rats Exposed Daily to
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
The procedure outlined above for continuous data was applied to the data for decreased
relative testis weight in male rats exposed daily to/;-a,a,a-tetrachlorotoluene by gavage for
90 days (Liao. 1989a. c). The data were not amenable to BMD modeling because neither the
constant nor nonconstant variance model provided adequate fit to the variance data
(see Table C-3). In an attempt to obtain an adequate fit, the highest dose was dropped because
there was a significant difference at the mid dose. After dropping the highest dose, the variance
data were still not adequately fit by either the constant or nonconstant variance models. No
model was selected. The linear model is shown in Table C-3 to demonstrate the lack of fit to the
variance data.
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Table C-3. BMD Modeling Results for Decreased Relative Testis Weight in Male S-D Rats
Exposed to />-a,a,a-Tetrachlorotoluene by Gavage for 90 Days
a
Variance
Means
Scaled Residual at
BMDisd (HED)
BMDLisd (HED)
Model
/>-Valucb
/>-Valucb
Dose Nearest BMD
AIC
(mg/kg-d)
(mg/kg-d)
All Doses (n = 10)
Constant Variance
Lineal
0.0001
0.12
-0.467
-109.93
2.21
1.72
Nonconstant Variance
Lineal
0.0008
0.11
-0.543
-114.19
3.00
2.17
Highest Dose Dropped
Constant Variance
Lineal
0.03
0.08
-0.129
-73.20
2.31
1.53
Nonconstant Variance
Lineal
0.02
0.10
-0.214
-72.68
2.07
1.26
aLiao (1989a. 1989c).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be negative.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose
associated with the selected BMR); BMDL = 95% lower confidence limit on the BMD (subscripts denote BMR:
i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose;
S-D = Sprague-Dawley; SD = standard deviation.
Increased Testicular Tubular Atrophy and Aspermatogenesis in Male S-D Rats Exposed
Daily to />-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
Liao (1989a) and Liao (1989c) presented testicular tubular atrophy both as total
incidences observed and as incidence by severity (mild, moderate, or marked). The incidence
data for both "total" and "marked" tubular atrophy and aspermatogenesis exhibited a positive
dose-related trend, and therefore, both data sets were separately fit to all available models in the
BMDS (Version 2.6) using the procedure outlined above for dichotomous data.
Total Incidence of Tubular Atrophy and Aspermatogenesis in Male S-D Rats Exposed
Daily to />-a,a,a-Tetrachlorotoluene via Gavage for 90 Days (Liao, 1989a, c)
For "total" incidence of tubular atrophy and aspermatogenesis in the testes, all models
provided an adequate fit (/;-value > 0.1; see Table C-4). BMDLs for models providing adequate
fit were not sufficiently close (differed by more than approximately threefold), so the model with
the lowest BMDL (1 -degree Multistage) was selected. Fit of the 1 -degree Multistage model to
the data is shown in Figure C-2. Based on HEDs, the estimated BMDio and BMDLio for total
incidence of testicular tubular atrophy and aspermatogenesis were 0.267 and 0.167 mg/kg-day,
respectively.
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Table C-4. BMD Modeling Results for Increased Total Incidence of Tubular Atrophy and Aspermatogenesis in Testes of Male S-D
Rats Exposed Daily to/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days3
Model
X2 Goodness-of-Fit
/>-Valucb
Scaled Residual at
Dose Nearest BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Gamma0
1.00
-0.001
14.22
2.17
0.410
Logistic
1.00
-0.00
16.22
2.91
0.980
LogLogisticd
1.00
-0.00
14.22
2.85
0.542
LogProbitd
1.00
0.00
16.22
2.66
0.482
Multistage (1-degree)' f
0.52
-1.20
18.46
0.267
0.167
Multistage (2-degree)6
0.98
-0.36
14.63
0.981
0.311
Multistage (3-degree)6
1.00
-0.11
14.24
1.50
0.310
Probit
1.00
0.00
16.22
2.50
0.858
Weibull0
1.00
0.00
16.22
2.33
0.392
aLiao (1989a. 1989c).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Tower restricted to >1.
dSlope restricted to >1.
"Betas restricted to >0.
Selected model.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose;
S-D = Sprague-Dawley.
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Multistage Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
13:52 07/02 2018
Figure C-2. Fit of the Multistage (1-Degree) Model to the Data for Increased Total
Incidence of Tubular Atrophy and Aspermatogenesis in Testes of Male S-D Rats Exposed
Daily to /;-o,o,o-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
BMD Model Output for Figure C-2:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File: C:/Users/sstevens/Documents/BMDS/BMDS2704/Input
data/mst_Liao_l98 9_Total_TubAtro_Mstl-BMR10-Restrict. (d)
Gnuplot Plotting File: C:/Users/sstevens/Documents/BMDS/BMDS2704/Input
data/mst_Liao_l98 9_Total_TubAtro_Mstl-BMR10-Restrict.pit
Mon Jul 02 13:52:12 2018
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
Dependent variable = Effect
Independent variable = Dose
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Total number of observations = 4
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0
Beta(1) = 1.39855e+019
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Background
have been estimated at a boundary point, or have been specified by
and do not appear in the correlation matrix )
Beta(1)
1
Parameter Estimates
the user,
Beta(1)
Interval
Variable
Limit
Background
Beta(1)
0.620418
Estimate
0
0.395021
Std. Err.
NA
0.115001
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
0.169623
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
Model
Full model
Fitted model
Reduced model
Analysis of Deviance Table
Log(likelihood) # Param's Deviance Test d.f.
-6.10864 4
-8.229
-27.2742
4.24072
42.3311
P-value
0.2366
<.0001
AIC: 18.458
Goodness of Fit
Dose Est._Prob. Expected Observed Size
Scaled
Residual
0.0000
0.3420
3.3800
6.7000
0.0000
0.1264
0.7369
0.9291
Chi^2 = 2.28 d.f. = 3
Benchmark Dose Computation
Specified effect = 0.1
0.000 0.000 10.000 0.000
1.264 0.000 10.000 -1.203
7.369 7.000 10.000 -0.265
9.291 10.000 10.000 0.873
P-value = 0.5164
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Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.266721
BMDL = 0.167101
BMDU = 0.4372 93
Taken together, (0.167101, 0.437293) is a 90 % two-sided confidence
interval for the BMD
Marked Tubular Atrophy and Aspermatogenesis in Male S-D Rats Exposed Daily to
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
For incidence of "marked" tubular atrophy and aspermatogenesis in the testes, all models
provided an adequate fit (p-value > 0.1; see Table C-5). BMDLs for models providing adequate
fit were not sufficiently close (differed by more than approximately threefold), so the model with
the lowest BMDL (LogLogistic) was selected. Fit of the LogLogistic model to the data is shown
in Figure C-3. Based on HEDs, the estimated BMDio and BMDLio for increased incidence of
marked testicular tubular atrophy and aspermatogenesis were 1.14 and 0.260 mg/kg-day,
respectively.
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Table C-5. BMD Modeling Results for Increased Incidence of Marked Tubular Atrophy and Aspermatogenesis in Testes of Male
S-D Rats Exposed Daily to />-a,a,a-Tetrachlorotoluene by Gavage for 90 Days3
Model
X2 Goodness-of-Fit
/>-Valueb
Scaled Residual at
Dose Nearest BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Gamma0
0.76
-0.397
30.78
1.12
0.389
Logistic
0.18
1.35
34.33
1.89
1.19
LogLogisticd'e
0.85
-0.348
30.51
1.14
0.260
LogProbitd
0.91
-0.236
30.32
1.12
0.649
Multistage (1-degree/
0.87
-0.796
29.39
0.587
0.369
Multistage (2-degree/
0.68
-0.665
31.27
0.798
0.373
Multistage (3-degree/
0.68
-0.665
31.27
0.798
0.373
Probit
0.21
-0.662
33.71
1.82
1.16
Weibull0
0.73
-0.497
30.94
1.01
0.384
aLiao (1989a. 1989c).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Tower restricted to >1.
dSlope restricted to >1.
"Selected model.
fBetas restricted to >0.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose;
S-D = Sprague-Dawley.
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Log-Logistic Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
13:38 07/02 2018
Figure C-3. Fit of LogLogistic Model to Data for Incidence of Marked Tubular Atrophy
and Aspermatogenesis in Testes of Male S-D Rats Exposed Daily to
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
BMD Model Output for Figure C-3:
Logistic Model. (Version: 2.15; Date: 3/20/2017)
Input Data File: C:/Users/sstevens/Documents/BMDS/BMDS2704/Input
data/lnl_Liao_198 9_MarkedTubAtro_Lnl-BMR10-Restrict.(d)
Gnuplot Plotting File: C:/Users/sstevens/Documents/BMDS/BMDS2704/Input
data/lnl_Liao_198 9_MarkedTubAtro_Lnl-BMR10-Restrict.pit
Mon Jul 02 13:38:39 2018
BMDS Model Run
The form of the probability function is:
P[response] = background+(1-background)/[1+EXP(-intercept-siope*Log(dose)) ]
Dependent variable = Effect
Independent variable = Dose
Slope parameter is restricted as slope >= 1
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Total number of observations = 4
Total number of records with missing values = 0
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
User has chosen the log transformed model
Default Initial Parameter Values
background = 0
intercept = -1.62862
slope = 1.31342
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -background have been estimated at a boundary
point, or have been specified by the user, and do not appear in the correlation matrix
)
intercept
slope
intercept
1
-0. 94
slope
-0.94
Interval
Variable
Limit
background
intercept
slope
Estimate
0
-2.44383
1.83497
Parameter Estimates
95.0% Wald Confidence
Std. Err. Lower Conf. Limit Upper Conf.
NA
1.36492
0.883994
-5.11903
0.102376
0.231366
3.56757
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
Model
Full model
Fitted model
Reduced model
AIC:
Analysis of Deviance Table
Log(likelihood)
-13.0401
-13.2557
-24.4346
30.5113
# Param's Deviance Test d.f.
4
2 0.431111 2
1 22.7889 3
P-value
0.8061
<.0001
Dose
Est. Prob.
Goodness of Fit
Expected
Observed
Size
Scaled
Residual
0.0000
0.3420
3.3800
6.7000
Chi^2 = 0.31
0.0000
0.0120
0.4479
0.7401
d.f. = 2
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
0.000 0.000 10.000 0.000
0.120 0.000 10.000 -0.348
4.479 5.000 10.000 0.331
7.401 7.000 10.000 -0.289
P-value = 0.8545
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Confidence level
0. 95
BMD
1.14384
BMDL
0.260665
BMDU
2.44074
Decreased Lymphocyte Counts in Male S-D Rats Exposed Daily to
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
The procedure outlined above for continuous data was applied to the data for decreased
lymphocyte count in male rats exposed daily to /;-a,a,a-tetrachlorotoluene by gavage for 90 days
(Liao. 1989a. c). The constant variance model provided an adequate fit (/rvalue > 0.1) to the
variance data, and with that model applied, each of the tested models provided adequate fit to the
means, except for the Exponential 5 and Hill models (see Table C-6). BMDLs for models
providing adequate fit were not sufficiently close (differed by more than approximately
threefold), so the model with the lowest BMDL was selected (Exponential Model 4). Figure C-4
shows the fit of the Exponential Model 4 to the data. Based on HEDs, the estimated BMDisd
and BMDLisd for decreased lymphocyte count in males were 1.38 and 0.489 mg/kg-day,
respectively.
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Table C-6. BMD Modeling Results for Decreased Lymphocytes in Male S-D Rats Administered
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days3
Model
Variance
/>-Valucb
Means
/>-Valucb
Scaled Residual at Dose
Nearest BMD
AIC
BMDisd (HED)
(mg/kg-d)
BMDLisd (HED)
(mg/kg-d)
Exponential (model 2)°
0.27
0.46
-0.99
104.25
2.32
1.59
Exponential (model 3)°
0.27
0.46
-0.99
104.25
2.32
1.59
Exponential (model 4)c'd
0.27
0.62
0.36
104.94
1.38
0.489
Exponential (model 5)°
0.27
NA
1.12 x 10-7
106.70
1.84
0.515
Hillc
0.27
NA
7.18 x 10-8
106.70
1.65
NDr
Lineal
0.27
0.23
-1.44
105.67
3.00
2.23
Polynomial (2-degree)6
0.27
0.23
-1.44
105.67
3.00
2.23
Polynomial (3-degree)6
0.27
0.23
-1.44
105.67
3.00
2.23
Power0
0.27
0.23
-1.44
105.67
3.00
2.23
aLiao (1989a. 1989c).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Tower restricted to be >1.
dSelected model.
"Coefficients restricted to be negative.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; DF = degree(s) of freedom;
HED = human equivalent dose; NA = not applicable; NDr = not determined; S-D = Sprague-Dawley; SD = standard deviation.
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Exponential 4 Model, with BMR of 1 Std. Dev. for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
16:06 07/02 2018
Figure C-4. Fit of Exponential (Model 4) to Data for Decreased Lymphocytes in Male S-D
Rats Administered/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
BMD Model Output for Figure C-4:
Exponential Model. (Version: 1.11; Date: 03/14/2017)
Input Data File: C:/Users/sstevens/Documents/BMDS/BMDS2704/Input
data/exp_Liao_198 9_lymphocytes_M_Exp-ConstantVariance-BMRlStd-Down. (d)
Gnuplot Plotting File:
Mon Jul 02 16:06:05 2018
BMDS Model Run
The form of the response function by Model:
Model 2
Model 3
Model 4
Model 5
Y[dose] = a * exp(sign * b * dose)
Y[dose] = a * exp(sign * (b * dose)Ad)
Y[dose] = a * [c-(c-l) * exp(-b * dose)]
Y[dose] = a * [c-(c-l) * exp(-(b * dose)Ad)]
Note: Y[dose] is the median response for exposure
sign = +1 for increasing trend in data;
sign = -1 for decreasing trend.
dose;
Model 2 is nested within Models 3 and 4.
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Model 3 is nested within Model 5.
Model 4 is nested within Model 5.
Dependent variable = Mean
Independent variable = Dose
Data are assumed to be distributed: normally
Variance Model: exp(lnalpha +rho *ln(Y[dose]))
rho is set to 0.
A constant variance model is fit.
Total number of dose groups = 4
Total number of records with missing values = 0
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
MLE solution provided: Exact
Initial Parameter Values
Variable Model 4
lnalpha 1.41757
rho 0 Specified
a 10.2165
b 0.450968
c 0.491269
d 1 Specified
Parameter Estimates
Variable Model 4 Std. Err.
lnalpha 1.42355 0.928377
a 9.91074 0.522831
b 0.366137 0.27681
c 0.482456 0.136117
Table of Stats From Input Data
Dose N Obs Mean Obs Std Dev
0 10 9.73 2.65
0.342 10 9.54 2.28
3.38 10 6.17 1.4
6.7 10 5.27 2.04
Estimated Values of Interest
Dose Est Mean Est Std Scaled Residual
0 9.911 2.038 -0.2805
0.342 9.307 2.038 0.3615
3.38 6.269 2.038 -0.1544
6.7 5.223 2.038 0.07335
Other models for which likelihoods are calculated:
Model A1: Yij = Mu(i) + e(ij)
Var(e(ij)) = Sigma^2
Model A2: Yij = Mu(i) + e(ij)
Var(e(ij)) = Sigma(i)^2
Model A3: Yij = Mu(i) + e(ij)
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Var(e(ij)) = exp(lalpha + log(mean(i)) * rho)
Model R: Yij = Mu + e(i)
Var(e(ij)) = SigmaA2
Likelihoods of Interest
Model
Log (likelihood)
DF
AIC
Al
-48.35132
5
106.7026
A2
-46.37436
8
108.7487
A3
-48.35132
5
106.7026
R
-61.74976
2
127.4995
4
-48.47097
4
104.9419
Additive constant for all log-likelihoods = -36.76. This constant added to the
above values gives the log-likelihood including the term that does not
depend on the model parameters.
Explanation of Tests
Does response and/or variances differ among Dose levels? (A2 vs. R)
Are Variances Homogeneous? (A2 vs. Al)
Are variances adeguately modeled? (A2 vs. A3)
Test
1:
Test
2 :
Test
3:
Test
6a
Tests of Interest
Test -2*log(Likelihood Ratio) D. F. p-value
Test 1 30.75
Test 2 3.954
Test 3 3.954
Test 6a 0.2393
D. F.
6
3
3
1
< 0.0001
0.2665
0.2665
0.6247
The p-value for Test 1 is less than .05. There appears to be a
difference between response and/or variances among the dose
levels, it seems appropriate to model the data.
The p-value for Test 2 is greater than .1. A homogeneous
variance model appears to be appropriate here.
The p-value for Test 3 is greater than .1. The modeled
variance appears to be appropriate here.
The p-value for Test 6a is greater than .1. Model 4 seems
to adeguately describe the data.
Benchmark Dose Computations:
Specified Effect = 1.000000
Risk Type = Estimated standard deviations from control
Confidence Level = 0.950000
BMD = 1.3827
BMDL = 0.4 9084 4
BMDU = 3.2753
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Decreased Lymphocyte Counts in Female S-D Rats Exposed Daily to
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
The procedure outlined above for continuous data was applied to the data for decreased
lymphocyte count in female rats exposed daily to /;-a,a,a-tetrachlorotoluene by gavage for
90 days (Liao. 1989a. c). The constant variance model did not provide an adequate fit to the
variance data (/;-value <0.1), but the nonconstant variance model did. With the nonconstant
variance model applied, all models except Exponential Model 5 provided an adequate fit
(p-value > 0.1) to the means (see Table C-7). BMDLs for models providing adequate fit were
sufficiently close (differed by less than approximately threefold), so the model with the lowest
AIC was selected (Linear). Figure C-5 shows the fit of the Linear model to the data. Based on
HEDs, the estimated BMDisd and BMDLisd for decreased lymphocyte count in females were
4.41 and 3.03 mg/kg-day, respectively.
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Table C-7. BMD Modeling Results for Decreased Lymphocytes in Female S-D Rats Administered to
/>-a,a,a-Tetrachlorotoluene by Gavage for 90 Days3
Model
Variance
/>-Valucb
Means
/>-Valucb
Scaled Residual at
Dose Nearest BMD
AIC
BMDisd (HED)
(mg/kg-d)
BMDLisd (HED)
(mg/kg-d)
Constant variance
Lineal
0.07
0.68
0.16
99.66
3.72
2.57
Nonconstant variance
Exponential (model 2)d
0.56
0.37
0.49
97.10
4.09
2.49
Exponential (model 3)d
0.56
0.16
0.26
99.05
4.32
2.50
Exponential (model 4)d
0.56
0.37
0.49
97.10
4.09
2.12
Exponential (model 5)d
0.56
NA
0.26
101.05
4.32
2.50
Hilld
0.56
0.18
0.18
98.89
4.41
3.17
Linear0'e
0.56
0.41
0.18
96.89
4.41
3.03
Polynomial (2-degree)0
0.56
0.18
-0.03
98.89
4.46
3.03
Polynomial (3-degree)0
0.56
0.18
-0.02
98.88
4.52
3.03
Power"1
0.56
0.41
0.18
96.89
4.41
3.03
aLiao (1989a. 1989c).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be negative.
dPower Restricted to >1
"Selected model.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose;
NA = not applicable; S-D = Sprague-Dawley; SD = standard deviation.
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Linear Model, with BMR of 1 Std. Dev. for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
13:08 07/03 2018
Figure C-5. Fit of Linear Model to Data for Decreased Lymphocytes in Female S-D Rats
Administered />-a,a,a-Tetrachlorotoluene by Gavage for 90 Days (Liao, 1989a, c)
BMD Model Output for Figure C-5:
Polynomial Model. (Version: 2.21; Date: 03/14/2017)
Input Data File: C:/Users/sstevens/Documents/BMDS/BMDS2704/Input
data/lin_Liao_198 9_lymphocytes_F_Lin-ModelVariance-BMRlStd. (d)
Gnuplot Plotting File: C:/Users/sstevens/Documents/BMDS/BMDS2704/Input
data/lin_Liao_198 9_lymphocytes_F_Lin-ModelVariance-BMRlStd.pit
Tue Jul 03 13:08:32 2018
BMDS Model Run
The form of the response function is:
Y[dose] = beta_0 + beta_l*dose + beta_2*dose/s2 + ...
Dependent variable = Mean
Independent variable = Dose
The polynomial coefficients are restricted to be negative
The variance is to be modeled as Var(i) = exp(lalpha + log(mean(i)) * rho)
Total number of dose groups = 4
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Total number of records with missing values = 0
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
lalpha = 1.42774
rho = 0
beta_0 = 6.72406
beta_l = -0.525385
Asymptotic Correlation Matrix of Parameter Estimates
lalpha
rho
beta_0
beta 1
lalpha
1
-0. 99
-0.014
0. 02
rho
-0.99
1
0. 014
-0.02
beta_0
-0.014
0.014
1
-0. 83
beta_l
0.02
-0.02
-0.83
1
Interval
Variable
Limit
lalpha
0.688109
rho
3.8281
beta_0
7.68168
beta_l
0.110966
Estimate
-2.27713
2.08269
6.73265
-0.528656
-0.746145
Parameter Estimates
Std. Err.
1.5129
0.890533
0.48421
-0.311166
Table of Data and Estimated Values of Interest
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
-5 .24236
0.337273
5.78362
Dose
N
Obs Mean
Est Mean Obs Std Dev Est Std Dev Scaled Res.
0 10
0.299 10
2.94 10
5.89 10
7.06
6.16
5.28
3.6
6.73
6.57
5.18
3. 62
2.9
1.73
1.9
1.29
Model Descriptions for likelihoods calculated
Model A1: Yij = Mu(i) + e(ij)
Var(e(ij)) = Sigma^2
Model A2: Yij = Mu(i) + e(ij)
Var(e(ij)) = Sigma(i)/S2
Model A3: Yij = Mu(i) + e(ij)
Var(e(ij)) = exp(lalpha + rho*ln(Mu(i)))
Model A3 uses any fixed variance parameters that
were specified by the user
Model R: Yi = Mu + e(i)
Var(e(i)) = Sigma^2
2.33
2.28
1.78
1.22
0.444
-0.576
0.181
-0.0488
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Likelihoods of Interest
Model
Log(likelihood)
# Param's
AIC
A1
-46.447513
5
102.895026
A2
-42.986072
8
101.972144
A3
-43.557729
6
99.115458
fitted
-44.444415
4
96.888830
R
-53.667146
2
111.334292
Explanation of Tests
Test 1
Test 2
Test 3
Test 4
(Note:
Tests of Interest
: Do responses and/or variances differ among Dose levels?
(A2 vs. R)
: Are Variances Homogeneous? (A1 vs A2)
: Are variances adeguately modeled? (A2 vs. A3)
: Does the Model for the Mean Fit? (A3 vs. fitted)
When rho=0 the results of Test 3 and Test 2 will be the same.)
Test
-2*log(Likelihood Ratio) Test df
p-value
Test
Test
Test
Test
21.3621
6.92288
1.14331
1.77337
0.001579
0. 0744
0.5646
0.412
The p-value for Test 1 is less than .05. There appears to be a
difference between response and/or variances among the dose levels
It seems appropriate to model the data
The p-value for Test 2 is less than .1. A non-homogeneous variance
model appears to be appropriate
The p-value for Test 3 is greater than .1. The modeled variance appears
to be appropriate here
The p-value for Test 4 is greater than .1. The model chosen seems
to adeguately describe the data
Benchmark Dose Computation
Specified effect = 1
Risk Type = Estimated standard deviations from the control mean
Confidence level = 0.95
BMD = 4.41348
BMDL = 3.032 65
BMDU = 7.419
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BMD Modeling to Identify Potential PODs for Derivation of a Provisional Reference
Concentration
Data on suitable endpoints from the 30-day and developmental inhalation studies were
modeled (Edwards et at.. 1985; Rose et ah. 1984). Modeled data from the 30-day study (Rose et
al., 1984) were increased incidences of atrophy of olfactory epithelium in male rats and
keratinizing epithelia hyperplasia in the larynx in female rats (see Table A-5 in Appendix A).
The Edwards et al. (1985) developmental toxicity study observed an increased incidence of
unossified sternebrae at the high-exposure concentration that could be modeled using individual
animal data from the study (see Table C-10) with the nested dichotomous models of the BMDS.
Summaries of modeling approaches and results (see Tables C-8 to C-l 1) are provided below.
Increased Atrophy of Olfactory Epithelium in Male Rats Exposed to
/>-a,a,a-Tetrachlorotoluene by Inhalation 6 Hours/Day, 5 Days/Week for 30 Days
The incidence data for atrophy of olfactory epithelium in male rats (Rose et al.. 1984)
were fit to all available dichotomous models in the BMDS (Version 2.6) using the procedure
described above dichotomous data. HECs for extrathoracic effects (HECet) were calculated
using the equation for ET effects from a Category 1 gas (U.S. HP A. 1994). HECet = TWA
concentration (mg/m3) x RGDRet, where RGDRet is the extrathoracic regional gas dose ratio
(animal:human) and TWA is the time-weighted average. RGDRet was calculated as per U.S.
EPA (1994) using default human minute volume (Ve), human and animal respiratory tissue
surface area values, and animal Ve values calculated from TWA body weights for each dose
group in the study. TWA body weights were calculated from weekly measured body weights
given in Table 5 in Rose et al. (1984). TWA body weights (grams) for the 0, 3.98, 18.9, and
94.5 mg/m3 groups, respectively, were: males = 303.6, 304.7, 298.1, and 201.2; females = 203.2,
203.4, 202.5, and 159.5. All models provided an adequate fit (p-value >0.1; see Table C-8).
Benchmark concentration lower confidence limits (BMCLs) for models providing adequate fit
were not sufficiently close (differed by more than approximately threefold), so the model with
the lowest BMCL was selected (LogLogistic). Figure C-6 shows the fit of the LogLogistic
model to the data, using a BMR of 10% extra risk. Based on human equivalent concentrations
(HECs), the BMC io and BMCLio for increased incidence of atrophy of the olfactory epithelium
in male rats were 0.0989 and 0.0141 mg/m3, respectively.
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Table C-8. BMC Modeling Results for Atrophy of Olfactory Epithelium in Male Albino Rats Exposed to />-a,a,a-Tetrachlorotoluene
by Inhalation 6 Hours/Day, 5 Days/Week for 30 Days3
Model
X2 Goodness-of-Fit
/>-Valueb
Scaled Residual at
Dose Nearest BMC
AIC
BMC 10 (HEC)
(mg/m3)
BMCLio (HEC)
(mg/m3)
Gamma0
1.00
0.011
14.02
0.0828
0.0245
Logistic
0.77
0.477
14.79
0.171
0.0777
LogLogisticd'e
0.94
0.085
14.23
0.0989
0.0141
LogProbitd
0.97
0.063
14.11
0.101
0.0409
Multistage (1-degree/
0.98
-0.342
12.20
0.0720
0.0245
Multistage (2-degree/
1.00
0.00
14.01
0.0714
0.0245
Multistage (3-degree/
1.00
0.00
16.01
0.158
0.0781
Probit
0.79
0.469
14.70
0.0793
0.0245
Weibull0
1.00
0.01
14.01
0.0480
0.0239
aRose et at (1984).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Tower restricted to >1.
dSlope restricted to >1.
"Selected model.
fBetas restricted to >0.
AIC = Akaike's information criterion; BMC = benchmark concentration (i.e., maximum likelihood estimates of the concentration associated with the selected BMR);
BMCL = 95% lower confidence limit on the BMC (subscripts denote BMR: i.e., 10 = exposure concentration associated with 10% extra risk); BMR = benchmark
response; HEC = human equivalent concentration.
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Log-Logistic Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
0.5 1 1.5 2 2.5
dose
16:11 08/23 2018
Figure C-6. Fit of LogLogistic Model to Data for Atrophy of Olfactory Epithelium in Male
Albino Rats Exposed to />-a,a,a-Tetrachlorotoluene by Inhalation 6 Hours/Day,
5 Days/Week for 30 Days (Rose et al., 1984) (BMR = 10% Extra Risk)
BMD Model Output for Figure C-6:
Logistic Model. (Version: 2.15; Date: 3/20/2017)
Input Data File: E:/lnl_olfactory_Lnl-BMR10-Restrict.(d)
Gnuplot Plotting File: E:/lnl_olfactory_Lnl-BMR10-Restrict.pit
Thu Aug 23 16:11:10 2018
BMDS Model Run
The form of the probability function is:
P[response] = background+(1-background)/[1+EXP(-intercept-siope*Log(dose))]
Dependent variable = Effect
Independent variable = Dose
Slope parameter is restricted as slope >= 1
Total number of observations = 4
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Total number of records with missing values = 0
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
User has chosen the log transformed model
Default Initial Parameter Values
background = 0
intercept = 1.50856
slope = 1.38397
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -background
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
intercept slope
intercept 1 0.77
slope 0.77 1
Parameter Estimates
Interval
Variable
Limit
background
intercept
4.85006
slope
3.73091
Estimate
0
2 .3792
1.97791
Std. Err.
NA
1.26067
0. 894408
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
-0.091669
0.224899
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-5.00402
-5.11334
-14.5323
# Param's
4
2
1
Deviance Test d.f.
0.218628
19.0565
P-value
0.8964
0. 0002661
AIC:
14.2267
Goodness of Fit
Scaled
Dose Est._Prob. Expected Observed Size Residual
0.0000 0.0000 0.000 0.000 5.000 0.000
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0.1420
0.1852
0.926 1.000
5.000
0. 085
0.6750
0.8323
4.161 4.000
5.000
-0.193
2.5300
0.9854
5.913 6.000
6.000
0.298
^2 = 0.13
d.f. = 2
P-value = 0.
, 9356
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.0988877
BMDL = 0.0141224
BMDU = 0.599202
Increased Keratinizing Epithelial Hyperplasia in the Larynx in Female Albino Rats
Exposed to />-a,a,a-Tetrachlorotoluene by Inhalation 6 Hours/Day, 5 Days/Week for
30 Days
The incidence data for keratinizing epithelial hyperplasia in the larynx of female rats
(Rose et al.. 1984) were fit to all available dichotomous models in the BMDS (Version 2.6) using
the procedure described above for dichotomous data. All models provided an adequate fit
(p-value >0.1; see Table C-9). BMCLs for models providing adequate fit were not sufficiently
close (differed by more than approximately threefold), so the model with the lowest BMCL was
selected (LogLogistic). Figure C-7 shows the fit of the LogLogistic model to the data, using a
BMR of 10% extra risk. Based on HECs, the BMCio and BMCLio for increased incidence of
keratinizing epithelial hyperplasia in the larynx of female rats were 0.0932 and 0.0182 mg/m3,
respectively.
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Table C-9. BMC Modeling Results for Keratinizing Epithelial Hyperplasia in the Larynx of Female Albino Rats Exposed to
/>-a,a,a-Tetrachlorotoluene by Inhalation 6 Hours/Day, 5 Days/Week for 30 Days3
Model
X2 Goodness-of-Fit
/>-Valueb
Scaled Residual at
Dose Nearest BMC
AIC
BMC 10 (HEC)
(mg/m3)
BMCLio (HEC)
(mg/m3)
Gamma0
0.69
0.44
16.64
0.0808
0.0348
Logistic
0.66
0.67
16.84
0.211
0.105
LogLogisticd'e
0.50
0.55
17.52
0.0932
0.0182
LogProbitd
0.63
0.80
15.54
0.110
0.0566
Multistage (1-degree/
0.87
0.31
14.67
0.0934
0.0361
Multistage (2-degree/
0.74
0.60
16.34
0.0904
0.0371
Multistage (3-degree/
0.80
0.57
16.15
0.196
0.0999
Probit
0.67
0.65
16.78
0.0907
0.0350
Weibull0
0.68
0.56
16.58
0.0689
0.0347
aRose et at (1984).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Tower restricted to >1.
dSlope restricted to >1.
"Selected model.
fBetas restricted to >0.
AIC = Akaike's information criterion; BMC = benchmark concentration (i.e., maximum likelihood estimates of the concentration associated with the selected BMR);
BMCL = 95% lower confidence limit on the BMC (subscripts denote BMR: i.e., 10 = exposure concentration associated with 10% extra risk); BMR = benchmark
response; HEC = human equivalent concentration.
97
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Log-Logistic Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
16:17 08/23 2018
Figure C-7. Fit of LogLogistic Model to Data for Keratinizing Epithelial Hyperplasia in the
Larynx of Female Albino Rats Exposed to />-a,a,a-Tetrachlorotoluene by Inhalation
6 Hours/Day, 5 Days/Week for 30 Days (Rose et al., 1984) (BMR = 10% Extra Risk)
BMD Model Output for Figure C-7:
Logistic Model. (Version: 2.15; Date: 3/20/2017)
Input Data File: E:/lnl_karatinizingdax_Lnl-BMR10-Restrict.(d)
Gnuplot Plotting File: E:/lnl_karatinizingdax_Lnl-BMR10-Restrict.pit
Thu Aug 23 16:17:18 2018
BMDS Model Run
The form of the probability function is:
P[response] = background+(1-background)/[1+EXP(-intercept-siope*Log(dose))]
Dependent variable = Effect
Independent variable = Dose
Slope parameter is restricted as slope >= 1
Total number of observations = 4
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Total number of records with missing values = 0
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
User has chosen the log transformed model
Default Initial Parameter Values
background = 0
intercept = 1.13901
slope = 1.27298
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -background
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
intercept slope
intercept 1 0.64
slope 0.64 1
Parameter Estimates
Interval
Variable
Limit
background
intercept
3.0062
slope
2.84021
Estimate
0
1.27968
1.46505
Std. Err.
NA
0.880893
0.701627
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
-0.446836
0.0898864
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-5.86707
-6.7585
-13.4602
# Param's
4
2
1
Deviance Test d.f.
1.78286
15.1863
P-value
0.4101
0.001664
AIC:
17.517
Goodness of Fit
Scaled
Dose Est._Prob. Expected Observed Size Residual
0.0000 0.0000 0.000 0.000 5.000 0.000
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0.553
-0.768
0.702
Chi^2 = 1.39 d.f. = 2 P-value = 0.4997
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.0931788
BMDL = 0.0182161
BMDU = 1.62 682
0.1070 0.1198 0.599 1.000 5.000
0.5060 0.5700 2.850 2.000 5.000
2.0300 0.9103 4.551 5.000 5.000
Increased Incidence of Unossified Sternebrae in CD (SD) BR Rat Fetuses Gestationally
Exposed to />-a,a,a-Tetrachlorotoluene Vapors on GDs 6-19
The modeling procedure outlined above for nested dichotomous data was applied to the
individual animal data for increased incidence of unossified sternebrae in fetuses from pregnant
rats exposed to/;-a,a,a-tetrachlorotoluene vapor by inhalation on Gestation Days (GDs) 6-19
(Edwards et ah. 1985). The individual animal data modeled are shown in Table C-10. The
NLogistic model was run using a BMR of 5% extra risk and was fit with and without the number
of implantations as a litter-specific covariate, which is the preferred choice of covariate when
dosing begins after implantation has taken place (U.S. EPA, 2018b). Each model was also fit
with and without taking account of intralitter correlations. Modeling results are shown in
Table C-l 1. Models not accounting for intralitter correlation did not provide adequate fit to the
data. All models including intralitter correlation provided adequate fit. Among all models, the
best fit (lowest AIC) was for the NLogistic model including number of implantations as a
covariate and accounting for intralitter correlation. BMCLs for the NCTR, and Rai and Van
Ryzin models with adequate fits were very small in relation to the corresponding BMCs
(> 10-fold difference) and were, therefore, considered unreliable. The NLogistic model with
covariate and intralitter correlation was selected. Figure C-8 shows the fit of the selected
NLogistic model to the data, using a BMR of 5% extra risk. Based on HECs, the BMCos and
BMCLos for increased unossified sternebrae in gestationally exposed fetuses were 1.38 and
0.385 mg/m3, respectively.
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Table C-10. Input Data of Unossified Sternebrae in CD (SD) BR Rat Fetuses Gestationally Exposed to />-a,a,a-Tetrachlorotoluene
Vapors on GDs 6-19a
Exposure Concentration
(HECer) (mg/m3)
Count of Dams within
Each Exposure Group
Experimental
Dam Number
Number of
Fetuses Examined
Number of Examined Fetuses
with Unossified Sternebrae
Number of
Implants
0
1
1
6
6
12
0
2
4
5
3
14
0
3
5
4
3
8
0
4
6
4
1
10
0
5
7
6
2
12
0
6
8
6
2
12
0
7
10
6
4
14
0
8
11
6
2
14
0
9
12
5
1
12
0
10
13
7
3
14
0
11
14
4
2
9
0
12
15
7
1
15
0
13
16
5
4
13
0
14
18
6
4
13
0
15
19
7
4
14
0
16
20
5
5
13
0
17
21
6
3
13
0
18
23
7
4
13
0
19
24
5
1
12
1.0
1
26
5
4
15
1.0
2
27
5
4
11
1.0
3
28
6
6
12
1.0
4
29
5
4
11
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Table C-10. Input Data of Unossified Sternebrae in CD (SD) BR Rat Fetuses Gestationally Exposed to />-a,a,a-Tetrachlorotoluene
Vapors on GDs 6-19a
Exposure Concentration
(HECer) (mg/m3)
Count of Dams within
Each Exposure Group
Experimental
Dam Number
Number of
Fetuses Examined
Number of Examined Fetuses
with Unossified Sternebrae
Number of
Implants
1.0
5
34
6
2
13
1.0
6
35
7
7
13
1.0
7
36
6
4
15
1.0
8
37
6
3
13
1.0
9
38
4
1
11
1.0
10
39
5
3
10
1.0
11
40
7
4
15
1.0
12
41
6
6
15
1.0
13
42
7
4
14
1.0
14
43
5
4
10
1.0
15
44
5
5
14
1.0
16
45
6
6
13
1.0
17
47
8
4
15
1.0
18
48
5
2
13
1.0
19
49
7
1
14
2.6
1
51
6
3
13
2.6
2
52
6
6
15
2.6
3
54
6
6
14
2.6
4
55
1
1
1
2.6
5
56
7
4
14
2.6
6
57
7
4
14
2.6
7
58
6
4
14
2.6
8
59
6
3
12
102
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Table C-10. Input Data of Unossified Sternebrae in CD (SD) BR Rat Fetuses Gestationally Exposed to />-a,a,a-Tetrachlorotoluene
Vapors on GDs 6-19a
Exposure Concentration
(HECer) (mg/m3)
Count of Dams within
Each Exposure Group
Experimental
Dam Number
Number of
Fetuses Examined
Number of Examined Fetuses
with Unossified Sternebrae
Number of
Implants
2.6
9
60
6
5
14
2.6
10
61
4
2
10
2.6
11
62
6
3
13
2.6
12
63
7
5
14
2.6
13
64
7
4
14
2.6
14
66
7
6
14
2.6
15
67
7
7
14
2.6
16
68
5
5
13
2.6
17
69
6
2
13
2.6
18
70
6
4
14
2.6
19
73
6
3
12
2.6
20
74
5
0
12
2.6
21
75
6
3
13
6.3
1
76
6
6
14
6.3
2
77
7
6
14
6.3
3
78
6
6
12
6.3
4
79
7
7
13
6.3
5
80
6
5
12
6.3
6
82
7
6
15
6.3
7
83
7
7
13
6.3
8
84
6
6
14
6.3
9
86
6
4
13
6.3
10
87
7
6
13
103
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September 2019
Table C-10. Input Data of Unossified Sternebrae in CD (SD) BR Rat Fetuses Gestationally Exposed to />-a,a,a-Tetrachlorotoluene
Vapors on GDs 6-19a
Exposure Concentration
(HECer) (mg/m3)
Count of Dams within
Each Exposure Group
Experimental
Dam Number
Number of
Fetuses Examined
Number of Examined Fetuses
with Unossified Sternebrae
Number of
Implants
6.3
11
88
5
5
11
6.3
12
90
6
5
13
6.3
13
91
2
1
5
6.3
14
92
7
7
14
6.3
15
93
5
5
11
6.3
16
94
6
4
12
6.3
17
95
5
4
10
6.3
18
97
5
4
11
6.3
19
98
6
6
14
6.3
20
99
5
3
9
6.3
21
100
4
2
11
aEdwards et al. (1985): individual litter data used for nested dichotomous modeling.
ER = extrarespiratory; GD = gestation day; HEC = human equivalent concentration.
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Table C-ll. BMC Modeling Results for Increased Incidence of Unossified Sternebrae in Fetuses of Pregnant CD (SD) BR Rats
Exposed to />-a,a,a-Tetrachlorotoluene Vapors on GDs 6-19a
X2 Goodness-of-Fit
Average Scaled Residual for
BMC (HEC)
BMCL (HEC)
Nested Model
/>-Valucb
AIC
Status of 0 and © Coefficients
Dose Group Nearest the BMC
(mg/m3)
(mg/m3)
Without number of implantations as a covariate, without intralitter correlation (BMR = 5% Extra Risk)
NLogistic0
0.0030
553.93
0s and ®s set = 0
2.04
0.86
0.125
NCTR0
0.0030
553.09
0s and ®s set = 0
-0.57
0.42
0.034
Rai and Van Ryzin0
0.0030
553.09
0s and ®s set = 0
-0.57
0.42
0.034
With number of implantations as a covariate, without intralitter correlation (BMR = 5% Extra Risk)
NLogistic0
0.0233
546.54
0s estimated nonzero; ®s set = 0
2.13
1.35
0.448
NCTR0
0.0083
552.84
0s estimated nonzero; ®s set = 0
2.07
0.65
0.333
Rai and Van Ryzin0
0.0047
554.81
0s estimated nonzero; ®s set = 0
-0.59
0.350
0.346
Without number of implantations as a covariate, with intralitter correlation (BMR = 5% Extra Risk)
NLogistic0
0.4363
547.37
0s set = 0; ®s estimated nonzero
1.42
0.98
0.112
NCTR0
0.4340
546.90
0s set = 0; ®s estimated nonzero
1.40
0.51
0.032
Rai and Van Ryzin0
0.4340
546.90
0s set = 0; ®s estimated nonzero
1.40
0.51
0.032
With number of implantations as a covariate, with intralitter correlation (BMR = 5% Extra Risk)
NLogistic0' d
0.6150
541.99
0 s and ©s estimated nonzero
1.48
1.38
0.3852
aEdwards et al. (1985): individual litter data used for nested dichotomous modeling.
bGoodness-of-fit /?-value combined from three bootstrap runs (adequate fit = p > 0.1).
Tower restricted > 1.
dSelected model.
AIC = Akaike's information criterion; BMC = benchmark concentration (i.e., maximum likelihood estimates of the concentration associated with the selected BMR);
BMCL = 95% lower confidence limit on the BMC; BMR = benchmark response; GD = gestation day; HEC = human equivalent concentration.
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Nested Logistic Model, with BMR of 5% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
3
dose
14:04 07/03 2018
Nested Logistic
BMDL
BMD
Figure C-8. Fit of the NLogistic Model to Data for Increased Incidence of Unossified
Sternebrae in CD (SD) BR Rat Fetuses Gestationally Exposed to
/>-a,a,a-Tetrachlorotoluene Vapors on GDs 6-19 (Edwards et al., 1985)
(BMR = 5% Extra Risk)
BMD Model Output for Figure C-8:
NLogistic Model. (Version: 2.20; Date: 04/27/2015)
Input Data File: //Esc-serverl/ncea_eh028/TO3+5 PTV lit search and
develop/p-a,a,a-Tetrachlorotoluene_5216-25-l/Working Toxicologist
folder/Revisions_07_02_l8/Edwards_BMD/nln_unossimplantrevised7_3_18_Nln-BMR05-Restrict
. (d)
Tue Jul 03 14:04:28 2018
BMDS Model Run
The probability function is:
Prob. = alpha + thetal*Rij + [1 - alpha - thetal*Rij]/
[1+exp(-beta-theta2*Rij-rho*log(Dose))],
where Rij is the litter specific covariate.
106
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Restrict Power rho >= 1.
Total number of observations = 8 0
Total number of records with missing values = 0
Total number of parameters in model = 9
Total number of specified parameters = 0
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Number of Bootstrap Iterations per run: 1000
Bootstrap Seed: 1530641068
Default Initial Parameter Values
alpha =
beta =
thetal =
theta2 =
rho =
phil =
phi 2 =
phi 3 =
phi 4 =
0.559308
-2.9069
0
0
2.01147
0. 0873332
0.227117
0.11692
0
Parameter Estimates
Variable
Estimate
Std. Err
alpha
0.695632
0.269444
beta
-13.046
4.76798
thetal
-0.0122555
0.0865844
theta2
0.745807
0.328334
rho
2.50645
0. 883357
phil
0.0791273
0.0893591
phi 2
0.236125
0.14086
phi 3
0.0587824
0.0861943
phi 4
0
Bounded
)g-likelihood
: -262,
.994 AIC: 541.
989
Litter
Data
Lit.
-Spec.
Litter
Scaled
Dose
Cov.
Est. Prob. Size
Expected (
Observed
Residual
0.0000
8.
0000
0.598
4
2.390
3
0.5588
0.0000
9.
0000
0.585
4
2.341
2
-0.3114
0.0000
10.
0000
0.573
4
2.292
1
-1.1744
0.0000
12.
0000
0.549
6
3.291
6
1.8809
0.0000
12.
0000
0.549
6
3.291
2
-0.8968
0.0000
12.
0000
0.549
5
2.743
1
-1.3650
0.0000
12.
0000
0.549
6
3.291
2
-0.8968
0.0000
12.
0000
0.549
5
2.743
1
-1.3650
0.0000
13.
0000
0.536
6
3.218
3
-0.1510
0.0000
13.
0000
0.536
5
2. 682
4
1.0305
0.0000
13.
0000
0.536
5
2. 682
5
1.8121
0.0000
13.
0000
0.536
7
3.754
4
0.1534
0.0000
13.
0000
0.536
6
3.218
4
0.5420
0.0000
14.
0000
0.524
6
3.144
4
0.5921
0.0000
14.
0000
0.524
6
3.144
2
-0.7918
0.0000
14.
0000
0.524
5
2. 620
3
0.2964
0.0000
14.
0000
0.524
7
3. 668
4
0.2067
0.0000
14.
0000
0.524
7
3. 668
3
-0.4165
0.0000
15.
0000
0.512
7
3.583
1
-1.6080
107
p-a, a, a-T etrachl orotoluene
-------
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 0000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
. 6000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
.3000
FINAL
September 2019
10.0000
10.0000
11.0000
11.0000
11.0000
12.0000
13.0000
13.0000
13.0000
13.0000
13.0000
14.0000
14.0000
14.0000
15.0000
15.0000
15.0000
15.0000
15.0000
0.575
0.575
0.564
0.564
0.564
0.556
0.552
0.552
0.552
0.552
0.552
0.557
0.557
0.557
0.578
0.578
0.578
0.578
0.578
2.873
2.873
2.257
2.821
2.821
3.336
3.312
.312
.312
.760
,864
.784
3.
3.
2.
3.
3.
2.
3. 898
4.043
3.466
2.888
3.466
4. 621
0.0822
0.7309
-0.9698
0.7624
0.7624
1.4825
-0.1735
-0.7295
1.4943
-0.4902
1.5332
-1.4182
1.4306
0.0501
-0.0213
0.2990
0.7219
1.4184
-0.2729
1.0000
10.0000
12.0000
12.0000
12.0000
13.0000
13.0000
13.0000
13.0000
13.0000
14.0000
14.0000
14.0000
14.0000
14.0000
14.0000
14.0000
14.0000
14.0000
14.0000
15.0000
0. 683
0.590
0. 618
0. 618
0. 618
0. 665
0. 665
0. 665
0. 665
0. 665
0.737
0.737
0.737
0.737
0.737
0.737
0.737
0.737
0.737
0.737
0. 820
0. 683
2.360
3. 091
3.709
3.709
3.326
3. 991
3. 991
3. 991
3. 991
4.423
5.160
, 160
, 160
, 160
, 423
, 423
, 160
5.160
4.423
4.919
-2
0.6807
0.3371
5603
0.5240
0.5240
1.4277
0.7533
1.5138
0.7533
0.7533
0.3448
1.3584
0.6201
0.8565
0.1182
0.4705
0.3448
0.8565
0.8565
1.2859
1.0096
5.0000
9.0000
10.0000
11.0000
11.0000
11.0000
11.0000
12.0000
12.0000
12.0000
13.0000
13.0000
13.0000
13.0000
13.0000
14.0000
14.0000
14.0000
14.0000
14.0000
15.0000
0. 638
0. 648
0. 690
0.755
0.755
0.755
0.755
0. 831
0. 831
0. 831
0. 898
0. 898
0. 898
0. 898
0. 898
0. 944
0. 944
0. 944
0. 944
0. 944
0. 971
1.275
3.241
, 450
, 022
.777
.777
.777
, 988
4.988
4.988
6.284
5.387
6.284
5.387
6.284
, 606
, 662
, 662
, 606
, 662
6.795
-1
0.4049
0.2261
0.5317
1882
0.2321
1.2725
1.2725
1.1032
1.0773
0.0130
0.8929
0.5208
0.3546
1.8683
0.8929
0.9933
0.5984
0.5984
0.6463
0.5984
1.7853
108
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Scaled Residual(s) for Dose Group Nearest the BMD
1.4825
1.4825
1.4825
1.4825
1.4825
1.4825
iMuiruoer or litters used ror scaled residual ror dose group nearest the BMD = 1
Observed Chi-square = 7 6.2170
Bootstrapping Results
Number of Bootstrap Iterations per run: 1000
Bootstrap Chi-square Percentiles
Bootstrap
Run P-value 5 0th 90th 95th 99th
1 0.6130 79.0982 95.0855 100.2383 111.9835
2 0.6070 78.9837 94.8173 100.5251 111.7723
3 0.6250 79.7000 94.1364 99.4197 113.7194
Combined 0.6150 79.1795 94.8401 100.3218 112.2275
Minimum scaled residual for dose group nearest the BMD =
Minimum ABS(scaled residual) for dose group nearest the BMD
Average scaled residual for dose group nearest the BMD =
Average ABS(scaled residual) for dose group nearest the BMD
Maximum scaled residual for dose group nearest the BMD =
Maximum ABS(scaled residual) for dose group nearest the BMD
The results for three separate runs are shown. If the estimated p-values are
sufficiently
stable (do not vary considerably from run to run), then then number of iterations is
considered adequate. The p-value that should be reported is the one that combines
the results of the three runs. If sufficient stability is not evident (and especially
if the p-values are close to the critical level for determining adequate fit, e.g.,
0.05) ,
then the user should consider increasing the number of iterations per run.
To calculate the BMD and BMDL, the litter specific covariate is fixed
at the mean litter specific covariate of control group: 12.473684
Benchmark Dose Computation
Specified effect = 0.05
Risk Type = Extra risk
Confidence level = 0.95
BMD = 1.37525
BMDL = 0.385229
BMD MODELING TO IDENTIFY POTENTIAL PODs FOR THE DERIVATION OF A
PROVISIONAL ORAL SLOPE FACTOR
Significant dose-related trends were found for increases in lung adenocarcinoma and
multiple adenoma, forestomach squamous cell carcinoma and carcinoma in situ, thymomas,
malignant lymphomas, and skin squamous cell carcinomas in female ICR mice treated with
p-a,a,a-tetrachlorotoluene by gavage twice per week for 17.5 weeks (Fukuda et al .. 1980. 1979).
MSCombo multiple-tumor BMD modeling was used to combine the tumor incidence data for
all of these tumor types. For each tumor type, the best-fitting Multistage model (i.e., the degree
109
p-a, a, a-T etrachl orotoluene
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September 2019
of Poly setting) was maintained in the MSCombo model run. The calculated combined tumor
BMDLio (HED) based on the MS Combo model is 0.015 mg/kg-day. This BMDLio (HED) is
used as the POD to derive the provisional oral slope factor (p-OSF). Summaries of modeling
approaches and results for each data set follow.
Lung Adenocarcinomas in Female ICR Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene
for 17.5 Weeks
The modeling procedure described above for cancer incidence data was applied to the
incidence data for lung adenocarcinomas in female ICR mice treated with
/>-a,a,a-tetrachlorotoluene by gavage twice per week for 17.5 weeks (Fukuda et al.. 1980. 1979).
The data are shown in Table A-8 in the "Derivation of Provisional Cancer Potency
Values" section in Appendix A. Table C-12 summarizes the BMD modeling results. No model
provided adequate fit to the full data set. After dropping the highest dose group, the 1-degree
Multistage model provided adequate fit to the data. The higher degree polynomial models took
the form of the 1 -degree model. Figure C-9 shows the fit of the 1 -degree Multistage model to
the data. Based on HEDs, the BMDio and BMDLio for lung adenocarcinoma in female mice
were 0.047 and 0.033 mg/kg-day, respectively.
110
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Table C-12. BMD Modeling Results for Lung Adenocarcinoma in Female ICR Mice Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
X2 Goodness-of-Fit
Scaled Residual at
BMDio (HED)
BMDLio (HED)
Model
/>-Valucb
Dose Nearest BMD
AIC
(mg/kg-d)
(mg/kg-d)
All doses
Multistage (1-degree)0
0
NA
172.92
NA
NA
Multistage (2-degree)0
0
NA
172.92
NA
NA
Multistage (3-degree)0
0
NA
172.92
NA
NA
Multistage (4-degree)°
0
NA
172.92
NA
NA
Highest dose group dropped
Multistage (l-degree)c'd
0.14
0.823
129.37
0.047
0.033
Multistage (2-degree)0
0.14
0.823
129.37
0.047
0.033
Multistage (3-degree)0
0.14
0.823
129.37
0.047
0.033
aFukuda et at (1980): Fukuda et al. (1979)
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be positive.
dSelected model; all higher-order dose coefficients are zero.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose;
NA = not applicable (computation failed).
Ill
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Multistage Cancer Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
09:39 03/21 2019
Figure C-9. Fit of the Multistage (1-Degree) Model to Data for Lung Adenocarcinoma in
Female ICR Mice Orally Exposed to/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks (Fukuda et
al., 1980,1979) (Highest Dose Group Dropped)
BMD Model Output for Figure C-9:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File:
C:/Users/JSWART/Desktop/BMDS/BMDS26/Data/msc_Fukuda_lung_adenocarcinoma_Opt.(d)
Gnuplot Plotting File:
C:/Users/JSWART/Desktop/BMDS/BMDS26/Data/msc_Fukuda_lung_adenocarcinoma_Opt.pit
Thu Mar 21 09:39:11 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
112
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Dependent variable = Effect
Independent variable = Dose
Total number of observations = 5
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.121569
Beta(1) = 1.55634
Asymptotic Correlation Matrix of Parameter Estimates
Background Beta(l)
Background 1 -0.67
Beta (1) -0.67 1
Interval
Variable
Limit
Background
0.130513
Beta(1)
3.36422
Estimate
0.0276431
2.24651
Parameter Estimates
Std. Err.
0.0524855
0.570266
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
-0.0752265
1.12881
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-59.7504
-62.6831
-74.77
# Param's
5
2
1
Deviance Test d.f.
5.86545
30.0393
P-value
0.1183
<.0001
AIC:
129.366
Goodness of Fit
Scaled
Dose Est._Prob. Expected Observed Size Residual
0.0000 0.0276 0.719 0.000 26.000 -0.860
0.0280 0.0869 1.912 3.000 22.000 0.823
0.0720 0.1729 4.840 7.000 28.000 1.079
0.1800 0.3511 7.723 10.000 22.000 1.017
113
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September 2019
0.4400 0.6381 18.506 15.000 29.000
Chi^2 = 5.45 d.f. = 3 P-value = 0.1415
-1.355
Benchmark Dose Computation
Specified effect
Risk Type
Confidence level
BMD
BMDL
BMDU
0.1
Extra risk
0. 95
0.0468995
0.0330362
0.0764043
Taken together, (0.0330362, 0.0764043) is a 90
interval for the BMD
two-sided confidence
Cancer Slope Factor =
3.02698
Lung Multiple Adenomas in Female ICR Mice Orally Exposed to
p-a,a,a-Tetrachlorotoluene for 17.5 Weeks
The modeling procedure described above for cancer incidence data was applied to the
incidence data for multiple lung adenomas in female ICR mice treated with
/>-a,a,a-tetrachlorotoluene by gavage twice per week for 17.5 weeks (Fukuda et al.. 1980. 1979).
The data are shown in Table A-8 in the "Derivation of Provisional Cancer Potency Values"
section in Appendix A. Table C-13 summarizes the BMD modeling results. The 1-degree
Multistage model provided adequate fit to the data. The higher degree polynomial models took
the form of the 1-degree model. Figure C-10 shows the fit of the 1-degree Multistage model to
the data. Based on HEDs, the BMDio and BMDLio for multiple lung adenomas in female mice
were 0.127 and 0.092 mg/kg-day, respectively.
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Table C-13. BMD Modeling Results for Lung Multiple Adenoma in Female ICR Mice Orally Exposed to/>-a,a,a-Tetrachlorotoluene
for 17.5 Weeks3
Model
X2 Goodness-of-Fit
/>-Valucb
Scaled Residual at
Dose Nearest BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Multistage (l-degree)c'd
0.55
-1.11
140.21
0.127
0.092
Multistage (2-degree)0
0.55
-1.11
140.21
0.127
0.092
Multistage (3-degree)0
0.55
-1.11
140.21
0.127
0.092
Multistage (4-degree)°
0.55
-1.11
140.21
0.127
0.092
aFukuda et at (1980): Fukuda et al. (1979).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be positive.
dSelected model; all higher-order dose coefficients are zero.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose.
115
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Multistage Cancer Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
10:23 03/21 2019
Figure C-10. Fit of the Multistage (1-Degree) Model to Data for Lung Multiple Adenoma in
Female ICR Mice Orally Exposed to »-a,a,a-Tetrachlorotoluene for 17.5 Weeks (Fukudaet
al., 1980,1979)
BMD Model Output for Figure C-10:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File:
C:/Users/JSWART/Desktop/BMDS/BMDS26/Data/msc_Fukuda_lung_mulitple_adenoma_Opt.(d)
Gnuplot Plotting File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_lung_mulitple_adenoma_Opt.pit
Thu Mar 21 10:23:15 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
116
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Dependent variable = Effect
Independent variable = Dose
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.0667116
Beta(1) = 0.758435
Asymptotic Correlation Matrix of Parameter Estimates
Background Beta(l)
Background 1 -0.42
Beta (1) -0.42 1
Parameter Estimates
Interval
Variable
Limit
Background
0.100153
Beta(1)
1.17727
Estimate
0. 0428386
0.829035
95.0% Wald Confidence
Std. Err. Lower Conf. Limit Upper Conf.
0.0292427 -0.0144759
0.177674 0.480799
Model
Full model
Fitted model
Reduced model
Analysis of Deviance Table
#
Log(likelihood)
-66.4952
-68.1064
-85.4579
Param's
6
2
1
Deviance Test d.f.
3.22244
37.9254
P-value
0.5213
<.0001
AIC:
140.213
Goodness of Fit
Scaled
Dose Est._Prob. Expected Observed Size Residual
0.0000 0.0428
0.0280 0.0648
0.0720 0.0983
0.1800 0.1755
0.4400 0.3354
1.1000 0.6155
1.114 1.000
1.426 2.000
2.752 1.000
3.862 6.000
9.726 10.000
17.848 17.000
26.000 -0.110
22.000 0.497
28.000 -1.112
22.000 1.198
29.000 0.108
29.000 -0.324
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Chi^2 = 3.05 d.f. = 4 P-value = 0.5495
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.127088
BMDL = 0.092 0397
BMDU = 0.189035
Taken together, (0.0920397, 0.189035) is a 90 % two-sided confidence
interval for the BMD
Cancer Slope Factor = 1.08649
Thymomas in Female ICR Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene for
17.5 Weeks
The modeling procedure described above for cancer incidence data was applied to the
incidence data for thymomas in female ICR mice treated with/;-a,a,a-tetrachlorotoluene by
gavage twice per week for 17.5 weeks (Fukuda et al.. 1980. 1979). The data are shown in
Table A-8 in the "Derivation of Provisional Cancer Potency Values" section in Appendix A.
Table C-14 summarizes the BMD modeling results. The 1-degree Multistage model provided
adequate fit to the data. The higher degree polynomial models took the form of the 1 -degree
model. Figure C-l 1 shows the fit of the 1 -degree Multistage model to the data. Based on HEDs,
the BMDio and BMDLio for thymoma in female mice were 0.402 and 0.258 mg/kg-day,
respectively.
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Table C-14. BMD Modeling Results for Thymoma in Female ICR Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene for
17.5 Weeks3
Model
X2 Goodness-of-Fit
/>-Valucb
Scaled Residual at
Dose Nearest BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Multistage (l-degree)c'd
0.83
0.50
63.22
0.402
0.258
Multistage (2-degree)0
0.83
0.50
63.22
0.402
0.258
Multistage (3-degree)0
0.83
0.50
63.22
0.402
0.258
Multistage (4-degree)°
0.83
0.50
63.22
0.402
0.258
Multistage (5-degree)°
0.83
0.50
63.22
0.402
0.258
aFukuda et at (1980): Fukuda et al. (1979).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be positive.
dSelected model; all higher-order dose coefficients are zero.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose.
119
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Multistage Cancer Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
10:19 03/21 2019
Figure C-ll. Fit of the Multistage (1-Degree) Model to Data for Thymoma in Female ICR
Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene for 17.5 Weeks (Fukuda et al., 1980,
1979)
BMD Model Output for Figure C-ll:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File:
C:/Users/JSWART/Desktop/BMDS/BMDS26/Data/msc_Fukuda_thymoma_Opt.(d)
Gnuplot Plotting File:
C:/Users/JSWART/Desktop/BMDS/BMDS26/Data/msc_Fukuda_thymoma_Opt.pit
Thu Mar 21 10:19:56 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
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Dependent variable = Effect
Independent variable = Dose
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0
Beta(1) = 0.31175
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Background
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
Beta(1)
Beta (1) 1
Parameter Estimates
Interval
Variable
Limit
Background
Beta(1)
0.411125
Estimate
0
0.26233
Std. Err.
NA
0.0759173
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
0.113535
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-28.7156
-30.6091
-42.3055
# Param's
6
1
1
Deviance Test d.f.
3.78712
27.1799
P-value
0.5805
<.0001
AIC:
63.2183
Goodness of Fit
Scaled
Dose Est._Prob. Expected Observed Size Residual
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0.0000
0.0000
0.000
0.000
26.000
0. 000
0.0280
0.0073
0.161
0.000
22.000
-0.403
0.0720
0.0187
0.524
0.000
28.000
-0.731
0.1800
0.0461
1.015
0.000
22.000
-1.031
0.4400
0.1090
3.161
4.000
29.000
0.500
1.1000
0.2507
7.269
8.000
29.000
0.313
Chi^2 = 2.11 d.f. = 5 P-value = 0.8341
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.401633
BMDL = 0.25 82 98
BMDU = 0.673248
Taken together, (0.258298, 0.673248) is a 90 % two-sided confidence
interval for the BMD
Cancer Slope Factor = 0.38715
Malignant Lymphoma in Female ICR Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene
for 17.5 Weeks
The modeling procedure described above for cancer incidence data was applied to the
incidence data for malignant lymphoma in female ICR mice treated with
/>-a,a,a-tetrachlorotoluene by gavage twice per week for 17.5 weeks (Fukuda et al.. 1980. 1979).
The data are shown in Table A-8 in the "Derivation of Provisional Cancer Potency Values"
section in Appendix A. Table C-15 summarizes the BMD modeling results. All models
provided adequate fit to the data. The model with the lowest AIC was selected (4-degree
Multistage). Figure C-12 shows the fit of the 4-degree Multistage model to the data. Based on
HEDs, the BMDio and BMDLio for malignant lymphoma in female mice were 0.979 and
0.727 mg/kg-day, respectively.
122
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Multistage Cancer Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
08:31 04/09 2019
Figure C-12. Fit of the Multistage (4-Degree) Model to Data for Malignant Lymphomas in
Female ICR Mice Orally Exposed to »-a,a,a-Tetrachlorotoluene for 17.5 Weeks (Fukudaet
al.. 1980.1979)
BMD Model Output for Figure C-12:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_malignant_lynphoma_Opt. (d)
Gnuplot Plotting File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_malignant_lynphoma_Opt.pit
Wed Mar 27 14:05:55 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*dose/sl-beta2*dose/s2) ]
The parameter betas are restricted to be positive
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Dependent variable = Effect
Independent variable = Dose
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 3
Total number of specified parameters = 0
Degree of polynomial = 2
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.00968251
Beta(l) = 0
Beta(2) = 0.143174
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Beta(l)
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
Background Beta (2)
Background 1 -0.17
Beta (2) -0.17 1
Parameter Estimates
Interval
Variable
Limit
Background
0.0387171
Beta(1)
Beta(2)
0.234323
Estimate
0.0161135
0
0.117586
Std. Err.
0.0115327
NA
0.0595605
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
-0.00649009
0.000849759
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood) # Param's Deviance Test d.f. P-value
-21.8838
-24.4176
-28.5682
5.06757
13.3686
0.2804
0.02016
AIC:
52.8353
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Goodness of Fit
Scaled
Dose Est._Prob. Expected Observed Size Residual
0.0000
0.0161
0.419
1.000
26.000
0. 905
0.0280
0.0162
0.356
0.000
22.000
-0.602
0.0720
0.0167
0.468
1.000
28.000
0.784
0.1800
0.0199
0.437
0.000
22.000
-0.668
0.4400
0.0383
1.109
0.000
29.000
-1.074
1.1000
0.1466
4.251
5.000
29.000
0.393
. A2 = 3.55
d.f. = 4
P-
-value = 0.
, 4703
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.94 65 87
BMDL = 0.657968
BMDU = 1.654 02
Taken together, (0.657968, 1.65402) is a 90 % two-sided confidence
interval for the BMD
Cancer Slope Factor = 0.151983
Forestomach Carcinoma In Situ in Female ICR Mice Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks
The modeling procedure described above for cancer incidence data was applied to the
incidence data for forestomach carcinoma in situ in female ICR mice treated with
a-tetrachlorotoluene by gavage twice per week for 17.5 weeks (Fukuda et al.. 1980. 1979).
The data are shown in Table A-8 in the "Derivation of Provisional Cancer Potency Values"
section in Appendix A. Table C-16 summarizes the BMD modeling results. The 1-degree
Multistage model provided adequate fit to the data. The higher degree polynomial models took
the form of the 1-degree model. Figure C-13 shows the fit of the 1-degree Multistage model to
the data. Based on HEDs, the BMDio and BMDLio for forestomach carcinoma in situ in female
mice were 0.640 and 0.376 mg/kg-day, respectively.
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Table C-16. BMD Modeling Results for Forestomach Carcinoma In Situ in Female ICR Mice Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
Model
X2 Goodness-of-Fit
/>-Valucb
Scaled Residual at
Dose Nearest BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Multistage (l-degree)c'd
0.62
1.44
56.29
0.640
0.376
Multistage (2-degree)0
0.62
1.44
56.29
0.640
0.376
Multistage (3-degree)0
0.62
1.44
56.29
0.640
0.376
Multistage (4-degree)°
0.62
1.44
56.29
0.640
0.376
Multistage (5-degree)°
0.62
1.44
56.29
0.640
0.376
aFukuda et at (1980): Fukuda et al. (1979).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be positive.
dSelected model; all higher-order dose coefficients are zero.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose.
126
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Multistage Cancer Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
13:18 03/21 2019
Figure C-13. Fit of the Multistage (1-Degree) Model to Data for Forestomach Carcinoma In
Situ in Female ICR Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene for 17.5 Weeks
(Fukuda et al.. 1980.1979)
BMD Model Output for Figure C-13:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_forestomach_carcinoma_in_situ_Opt.
(d)
Gnuplot Plotting File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_forestomach_carcinoma_in_situ_Opt.
pit
Thu Mar 21 13:18:06 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
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Dependent variable = Effect
Independent variable = Dose
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.0159495
Beta(1) = 0.114105
Asymptotic Correlation Matrix of Parameter Estimates
the user,
Beta(1)
( *** The model parameter(s) -Background
have been estimated at a boundary point, or have been specified by
and do not appear in the correlation matrix )
Beta(1)
1
Parameter Estimates
Interval
Variable
Limit
Background
Beta(1)
0.278912
Estimate
0
0.164707
Std. Err.
NA
0.0582692
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
0.0505014
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-25.3477
-27.1465
-31.5546
# Param's
6
1
1
Deviance Test d.f.
3.59761
12.4138
P-value
0.6087
0.02954
AIC:
56.293
Goodness of Fit
Scaled
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Dose Est. Prob.
Expected
Observed Size
Residual
0.0000 0.0000
0.000
0.000 26.000
0. 000
0.0280 0.0046
0.101
0.000 22.000
-0.319
0.0720 0.0118
0.330
0.000 28.000
-0.578
0.1800 0.0292
0.643
1.000 22.000
0. 452
0.4400 0.0699
2.027
4.000 29.000
1. 437
1.1000 0.1657
4.806
3.000 29.000
-0.902
Chi^2 = 3.52 d.f.
= 5 P-
-value = 0.62 08
Benchmark Dose Computation
Specified effect =
0.1
Risk Type =
Extra risk
Confidence level =
0. 95
BMD =
0.639685
BMDL =
0.376269
BMDU =
1.33515
Taken together, (0.376269, 1.33515)
is a 90 % two-sided
confidence
interval for the BMD
Cancer Slope Factor =
0.265768
Forestomach Squamous Cell Carcinoma in Female ICR Mice Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks
The modeling procedure described above for cancer incidence data was applied to the
incidence data for forestomach squamous cell carcinoma in female ICR mice treated with
a-tetrachlorotoluene by gavage twice per week for 17.5 weeks (Fukuda et al.. 1980. 1979).
The data are shown in Table A-8 in the "Derivation of Provisional Cancer Potency Values"
section in Appendix A. Table C-17 summarizes the BMD modeling results. The 1-degree
Multistage model provided adequate fit to the data. The higher degree polynomial models took
the form of the 1-degree model. Figure C-14 shows the fit of the 1-degree Multistage model to
the data. Based on HEDs, the BMDio and BMDLio for forestomach squamous cell carcinoma in
female mice were 0.372 and 0.243 mg/kg-day, respectively.
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Table C-17. BMD Modeling Results for Forestomach Squamous Cell Carcinoma in Female ICR Mice Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
Model
X2 Goodness-of-Fit
/>-Valucb
Scaled Residual at
Dose Nearest BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Multistage (l-degree)c'd
0.51
1.50
69.36
0.372
0.243
Multistage (2-degree)0
0.51
1.50
69.36
0.372
0.243
Multistage (3-degree)0
0.51
1.50
69.36
0.372
0.243
Multistage (4-degree)°
0.51
1.50
69.36
0.372
0.243
Multistage (5-degree)°
0.51
1.50
69.36
0.372
0.243
aFukuda et at (1980): Fukuda et al. (1979).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be positive.
dSelected model; all higher-order dose coefficients are zero.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose.
130
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Multistage Cancer Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
10:00 03/21 2019
Figure C-14. Fit of the Multistage (1-Degree) Model to Data for Forestomach Squamous
Cell Carcinoma in Female ICR Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene for
17.5 Weeks (Fukuda et al.. 1980.1979)
BMD Model Output for Figure C-14:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_forestomach_squamous_cell_carcinom
a_Opt.(d)
Gnuplot Plotting File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_forestomach_squamous_cell_carcinom
a_Opt.pit
Thu Mar 21 10:22:18 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
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Dependent variable = Effect
Independent variable = Dose
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0
Beta(1) = 0.282909
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Background
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
Beta(1)
Beta (1) 1
Parameter Estimates
Interval
Variable
Limit
Background
Beta(1)
0.437999
Estimate
0
0.283505
Std. Err.
NA
0. 078825
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
0.12901
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-30.8119
-33.6778
-44.7464
# Param's Deviance Test d.f. P-value
6
1 5.73172 5 0.3332
1 27.869 5 <.0001
AIC:
69.3556
Goodness of Fit
Scaled
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Dose Est. Prob.
Expected
Observed
Size
Residual
0.0000 0.0000
0.000
0.000
26.000
0. 000
0.0280 0.0079
0.174
0.000
22.000
-0.419
0.0720 0.0202
0.566
0.000
28.000
-0.760
0.1800 0.0498
1.095
0.000
22.000
-1.073
0.4400 0.1173
3.401
6.000
29.000
1.500
1.1000 0.2679
7.769
7.000
29.000
-0.323
Chi^2 = 4.26 d.f.
= 5 P-
-value = 0.5128
Benchmark Dose Computation
Specified effect =
0.1
Risk Type =
Extra risk
Confidence level =
0. 95
BMD =
0.371636
BMDL =
0.242891
BMDU =
0.609459
Taken together, (0.242891, 0.609459)
is a 90 %
two-sided
confidence
interval for the BMD
Cancer Slope Factor =
0.411707
Skin Squamous Cell Carcinoma in Female ICR Mice Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks
The modeling procedure described above for cancer incidence data was applied to the
incidence data for skin squamous cell carcinoma in female ICR mice treated with
a-tetrachlorotoluene by gavage twice per week for 17.5 weeks (Fukuda et al.. 1980. 1979).
The data are shown in Table A-8 in the "Derivation of Provisional Cancer Potency Values"
section in Appendix A. Table C-18 summarizes the BMD modeling results. All models
provided adequate fit to the data. The model with the lowest AIC was selected (4-degree
Multistage). Figure C-15 shows the fit of the 4-degree Multistage model to the data. Based on
HEDs, the BMDio and BMDL io for skin squamous cell carcinoma in female mice were 0.957
and 0.721 mg/kg-day, respectively.
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Table C-18. BMD Modeling Results for Skin Squamous Cell Carcinoma in Female ICR
Mice Orally Exposed to />-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
Model
X2
Goodness-of-Fit
/>-Valucb
Scaled Residual at
Dose Nearest
BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Multistage (1-degree)0
0.65
1.13
37.76
1.02
0.530
Multistage (2-degree)0
0.96
0.45
30.51
0.900
0.649
Multistage (3-degree)0
1.00
0.16
29.38
0.927
0.696
Multistage (4-degree)c'd
1.00
0.06
28.95
0.957
0.721
aFukuda et al. (1980): Fukuda et al. (1979).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be positive.
dSelected model, based on lowest AIC for models with all dose coefficients >0.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose
associated with the selected BMR); BMDL = 95% lower confidence limit on the BMD (subscripts denote BMR:
i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose.
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Multistage Cancer Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
08:35 04/09 2019
Figure C-15. Fit of the Multistage (4-Degree) Model to Data for Skin Squamous Cell
Carcinoma in Female ICR Mice Orally Exposed to/>-a,a,a-Tetrachlorotoluene for
17.5 Weeks (Fukuda et al.. 1980.1979)
BMD Model Output for Figure C-15:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File:
C:/Users/JSWART/Desktop/BMDS/BMDS26/Data/msc_Fukuda_skin_squamous_cell_carcinoma_Opt. (
d)
Gnuplot Plotting File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_skin_squamous_cell_carcinoma_Opt.p
It
Wed Mar 27 14:11:28 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*dose/sl-beta2*dose/s2) ]
The parameter betas are restricted to be positive
135
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Dependent variable = Effect
Independent variable = Dose
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 3
Total number of specified parameters = 0
Degree of polynomial = 2
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0
Beta(l) = 0
Beta(2) = 0.158724
Asymptotic Correlation Matrix of Parameter Estimates
the user,
Beta(2)
( *** The model parameter(s) -Background -Beta(l)
have been estimated at a boundary point, or have been specified by
and do not appear in the correlation matrix )
Beta(2)
1
Parameter Estimates
Interval
Variable
Limit
Background
Beta(1)
Beta(2)
0.243978
Estimate
0
0
0.129953
Std. Err.
NA
NA
0.05817*
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
0.0159289
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood) # Param's Deviance Test d.f. P-value
-13.3311 6
-14.2549 1 1.8477 5 0.8698
-22.1211 1 17.58 5 0.003522
AIC:
30.5099
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Dose
Est. Prob.
Goodness of Fit
Expected Observed Size
Scaled
Residual
0.0000
0.0280
0.0720
0.1800
0.4400
1.1000
0.0000
0.0001
0.0007
0.0042
0. 0248
0.1455
0.000 0.000
0.002 0.000
0.019 0.000
0.092 0.000
0.721 0.000
4.220 5.000
26.000
22.000
28.000
22.000
29.000
29.000
0. 000
-0.047
-0.137
-0.305
-0.860
0.411
Chi^2 =1.02
d.f.
= 5 P-value = 0.
, 9608
Benchmark
Dose Computation
Specified effect =
0.1
Risk Type
=
Extra risk
Confidence level =
0. 95
BMD =
0.90042
BMDL =
0.6485
BMDU =
1.36941
Taken together, (0.6485
interval for the BMD
, 1.36941) is a 90
% two-sided
confidence
Cancer Slope
Factor =
0.154202
Forestomach Multiple Papillomas in Female ICR Mice Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks
The modeling procedure described above for cancer incidence data was applied to the
incidence data for forestomach multiple papillomas in female ICR mice treated with
a-tetrachlorotoluene by gavage twice per week for 17.5 weeks (Fukuda et al.. 1980. 1979).
The data are shown in Table A-8 in the "Derivation of Provisional Cancer Potency Values"
section in Appendix A. Table C-19 summarizes the BMD modeling results. No models
provided an adequate fit to the data with the highest two doses included, at which the incidence
was reduced. After dropping the highest two dose groups, the 1 -degree Multistage model
provided adequate fit to the data. The higher degree polynomial models took the form of the
1-degree model. Figure C-16 shows the fit of the 1-degree Multistage model to the data. Based
on HEDs, the BMDio and BMDLio for forestomach multiple papillomas in female mice were
0.0569 and 0.0359 mg/kg-day, respectively.
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Table C-19. BMD Modeling Results for Forestomach Multiple Papillomas in Female ICR Mice Orally Exposed to
/>-a,a,a-Tetrachlorotoluene for 17.5 Weeks3
Model
X2 Goodness-of-Fit
/>-Valucb
Scaled Residual at
Dose Nearest BMD
AIC
BMDio (HED)
(mg/kg-d)
BMDLio (HED)
(mg/kg-d)
Multistage (l-degree)c'd
0.76
0.29
63.00
0.0569
0.0359
Multistage (2-degree)0
0.76
0.29
63.00
0.0569
0.0359
Multistage (3-degree)0
0.76
0.29
63.00
0.0569
0.0359
aFukuda et at (1980): Fukuda et al. (1979).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
Coefficients restricted to be positive.
dSelected model; all higher degree coefficients are zero.
AIC = Akaike's information criterion; BMD = benchmark dose (i.e., maximum likelihood estimates of the dose associated with the selected BMR); BMDL = 95% lower
confidence limit on the BMD (subscripts denote BMR: i.e., 10 = dose associated with 10% extra risk); BMR = benchmark response; HED = human equivalent dose.
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Multistage Cancer Model, with BMR of 10% Extra Risk for the BMD and 0.95 Lower Confidence Limit for the BMDL
dose
07:24 03/26 2019
Figure C-16. Fit of the Multistage (1-Degree) Model to Data for Forestomach Multiple
Papillomas in Female ICR Mice Orally Exposed to/>-a,a,a-Tetrachlorotoluene for
17.5 Weeks (Fukuda et al.. 1980.1979)
BMD Model Output for Figure C-16:
Multistage Model. (Version: 3.4; Date: 05/02/2014)
Input Data File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_forestomach_multiple_papilloma_Opt
. (d)
Gnuplot Plotting File:
C:/Users/JSWART/Desktop/BMDS/BMDS2 6/Data/msc_Fukuda_forestomach_multiple_papilloma_Opt
. pit
Tue Mar 26 07:25:16 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
139
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Dependent variable = Effect
Independent variable = Dose
Total number of observations = 4
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.0342233
Beta(1) = 1.31428
Asymptotic Correlation Matrix of Parameter Estimates
the user,
Beta(1)
( *** The model parameter(s) -Background
have been estimated at a boundary point, or have been specified by
and do not appear in the correlation matrix )
Beta(1)
1
Parameter Estimates
Interval
Variable
Limit
Background
Beta(1)
2.94802
Estimate
0
1.85135
Std. Err.
NA
0.559537
NA - Indicates that this parameter has hit a bound
implied by some ineguality constraint and thus
has no standard error.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
0.754678
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-29.9764
-30.5006
-34.416
# Param's Deviance Test d.f. P-value
4
1 1.04855 3 0.7895
1 8.87918 3 0.03094
AIC:
63.0013
Goodness of Fit
Scaled
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Dose
Est. Prob.
Expected
Observed
Size
Residual
0.0000
0.0280
0.0720
0.1800
Chi^2 =1.17
0.0000
0.0505
0.1248
0.2834
d.f. = 3
0.000 0.000 26.000
1.111 2.000 22.000
3.494 4.000 28.000
6.235 5.000 22.000
P-value = 0.7594
0. 000
0. 865
0.289
-0.584
Benchmark Dose Computation
Specified effect
Risk Type
Confidence level
BMD
BMDL
BMDU
0.1
Extra risk
0. 95
0.0569101
0.0359441
0.138961
Taken together, (0.0359441, 0.138961) is a 90
interval for the BMD
two-sided confidence
Cancer Slope Factor =
2.7821
Screening p-OSF POD Selection Model: BMD Model Output for MS Combo Model of All
Tumors in Female ICR Mice Orally Exposed to p-a,a,a-Tetrachlorotoluene for 17.5 Weeks
MS_COMBO. (Version: 1.9; Date: 05/20/2014)
Input Data File:
C:\Users\JSWART\Desktop\BMDS\BMDS26\Data\SessionFiles\Fukuda_8_ms5.(d)
Gnuplot Plotting File:
C:\Users\JSWART\Desktop\BMDS\BMDS2 6\Data\SessionFiles\Fukuda_8_ms5.pit
Wed Mar 27 14:02:35 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
Dependent variable = Effect
Independent variable = Dose
Data file name = Fukuda_lung_adenocarcinoma.dax
Total number of observations = 5
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
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Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.121569
Beta(1) = 1.55634
Asymptotic Correlation Matrix of Parameter Estimates
Background Beta(l)
Background 1 -0.7
Beta (1) -0.7 1
Parameter Estimates
95.0% Wald Confidence
Interval
Variable Estimate Std. Err. Lower Conf. Limit Upper Conf.
Limit
Background 0.0276432 * * *
Beta(1) 2.24652 * * *
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-59.7504
-62.6831
-74.77
# Param's Deviance Test d.f. P-value
5
2 5.86545 3 0.1183
1 30.0393 4 <.0001
AIC:
129.366
Log-likelihood Constant
52.870081256733542
Dose
Est. Prob.
Goodness of Fit
Expected Observed Size
Scaled
Residual
0.0000
0.0280
0.0720
0.1800
0.4400
Chi^2 =5.45
0.0276
0.0869
0.1729
0.3511
0.6381
d.f. = 3
0.719 0.000 26.000 -0.860
1.912 3.000 22.000 0.823
4.840 7.000 28.000 1.079
7.723 10.000 22.000 1.017
18.506 15.000 29.000 -1.355
P-value = 0.1415
Benchmark Dose Computation
Specified effect = 0.1
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Risk Type
Confidence level
BMD
BMDL
BMDU
Extra risk
0. 95
0.0468995
0.0330362
0.0764043
Taken together, (0.0330362, 0.0764043) is a 90
interval for the BMD
two-sided confidence
Multistage Cancer Slope Factor =
3.02698
MS_COMBO. (Version: 1.9; Date: 05/20/2014)
Input Data File:
C:\Users\JSWART\Desktop\BMDS\BMDS26\Data\SessionFiles\Fukuda_8_ms5.(d)
Gnuplot Plotting File:
C:\Users\JSWART\Desktop\BMDS\BMDS2 6\Data\SessionFiles\Fukuda_8_ms5.pit
Wed Mar 27 14:02:35 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
Dependent variable = Effect
Independent variable = Dose
Data file name = Fukuda_lung_mulitple_adenoma.dax
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.0667116
Beta(1) = 0.758435
Asymptotic Correlation Matrix of Parameter Estimates
Background Beta(l)
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Background 1 -0.5 9
Beta (1) -0.59 1
Parameter Estimates
95.0% Wald Confidence
Interval
Variable Estimate Std. Err. Lower Conf. Limit Upper Conf.
Limit
Background 0.0428386 * * *
Beta(1) 0.829035 * * *
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
AIC:
Log(likelihood) # Param's Deviance Test d.f. P-value
-66.4952
-68.1064
-85.4579
140.213
Log-likelihood Constant
3.22244
37.9254
57.830282020725626
0.5213
<.0001
Dose
Goodness of Fit
Est. Prob.
Expected
Observed
Size
Scaled
Residual
0.0000
0.0280
0.0720
0.1800
0.4400
1.1000
Chi^2 = 3.05
0.0428
0.0648
0.0983
0.1755
0.3354
0.6155
d.f. = 4
1.114 1.000 26.000 -0.110
1.426 2.000 22.000 0.497
2.752 1.000 28.000 -1.112
3.862 6.000 22.000 1.198
9.726 10.000 29.000 0.108
17.848 17.000 29.000 -0.324
P-value = 0.5495
Benchmark Dose Computation
Specified effect
Risk Type
Confidence level
BMD
BMDL
BMDU
0.1
Extra risk
0. 95
0.127088
0.0920397
0.189035
Taken together, (0.0920397, 0.189035) is a 90
interval for the BMD
two-sided confidence
Multistage Cancer Slope Factor =
1.08649
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MS_COMBO. (Version: 1.9; Date: 05/20/2014)
Input Data File:
C:\Users\JSWART\Desktop\BMDS\BMDS26\Data\SessionFiles\Fukuda_8_ms5.(d)
Gnuplot Plotting File:
C:\Users\JSWART\Desktop\BMDS\BMDS2 6\Data\SessionFiles\Fukuda_8_ms5.pit
Wed Mar 27 14:02:35 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*dose/sl-beta2*dose/s2) ]
The parameter betas are restricted to be positive
Dependent variable = Effect
Independent variable = Dose
Data file name = Fukuda_malignant_lynphoma.dax
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 3
Total number of specified parameters = 0
Degree of polynomial = 2
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.00968251
Beta(l) = 0
Beta(2) = 0.143174
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Beta(l)
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
Background Beta (2)
Background 1 -0.45
Beta (2) -0.45 1
Parameter Estimates
95.0% Wald Confidence
Interval
145
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Variable Estimate Std. Err. Lower Conf. Limit Upper Conf.
Limit
Background 0.0161135 * * *
Beta(1) 0 * * *
Beta(2) 0.117586 * * *
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-21.8838
-24.4176
-28.5682
# Param's Deviance Test d.f. P-value
6
2 5.06757 4 0.2804
1 13.3686 5 0.02016
AIC:
52.8353
Log-likelihood Constant
18 .275118874470813
Dose
Est. Prob.
Goodness of Fit
Expected
Observed
Size
Scaled
Residual
0.0000
0.0280
0.0720
0.1800
0.4400
1.1000
0.0161
0.0162
0.0167
0.0199
0.0383
0.1466
0.419
0.356
0.468
0.437
1.109
4.251
1.000
0.000
1.000
0.000
0.000
5.000
26.000
22.000
28.000
22.000
29.000
29.000
0. 905
-0.602
0.784
-0.668
-1.074
0.393
Chi^2 = 3.55
d.f. = 4
P-value = 0.4703
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.94 65 87
BMDL = 0.657968
BMDU = 1.654 02
Taken together, (0.657968, 1.65402) is a 90 % two-sided confidence
interval for the BMD
Multistage Cancer Slope Factor = 0.151983
MS_COMBO. (Version: 1.9; Date: 05/20/2014)
Input Data File:
C:\Users\JSWART\Desktop\BMDS\BMDS26\Data\SessionFiles\Fukuda_8_ms5.(d)
Gnuplot Plotting File:
C:\Users\JSWART\Desktop\BMDS\BMDS2 6\Data\SessionFiles\Fukuda_8_ms5.pit
Wed Mar 27 14:02:35 2019
146
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BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
Dependent variable = Effect
Independent variable = Dose
Data file name = Fukuda_thymoma.dax
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0
Beta(1) = 0.31175
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Background
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
Beta(1)
Beta (1) 1
Parameter Estimates
95.0% Wald Confidence
Interval
Variable Estimate Std. Err. Lower Conf. Limit Upper Conf.
Limit
Background 0 * * *
Beta(1) 0.26233 * * *
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model Log(likelihood) # Param's Deviance Test d.f. P-value
147
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September 2019
Full model
Fitted model
Reduced model
-28.7156
-30.6091
-42.3055
3.78712
27.1799
0.5805
<.0001
AIC:
63.2183
Log-likelihood Constant
25 .347677079785861
Dose
Est. Prob.
Goodness of Fit
Expected
Observed
Size
Scaled
Residual
0.0000
0.0280
0.0720
0.1800
0.4400
1.1000
0.0000
0.0073
0.0187
0.0461
0.1090
0.2507
0.000
0.161
0.524
1.015
3.161
7.269
0.000
0.000
0.000
0.000
4.000
8.000
26.000
22.000
28.000
22.000
29.000
29.000
0. 000
-0.403
-0.731
-1.031
0.500
0.313
Chi^2 =2.11
d.f. = 5
P-value = 0.8341
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.401633
BMDL = 0.25 82 98
BMDU = 0.673248
Taken together, (0.258298, 0.673248) is a 90 % two-sided confidence
interval for the BMD
Multistage Cancer Slope Factor = 0.38715
MS_COMBO. (Version: 1.9; Date: 05/20/2014)
Input Data File:
C:\Users\JSWART\Desktop\BMDS\BMDS26\Data\SessionFiles\Fukuda_8_ms5.(d)
Gnuplot Plotting File:
C:\Users\JSWART\Desktop\BMDS\BMDS2 6\Data\SessionFiles\Fukuda_8_ms5.pit
Wed Mar 27 14:02:35 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
148
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Dependent variable = Effect
Independent variable = Dose
Data file name = Fukuda_forestomach_squamous_cell_carcinoma.dax
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0
Beta(1) = 0.282909
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Background
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
Beta(1)
Beta (1) 1
Parameter Estimates
95.0% Wald Confidence
Interval
Variable Estimate Std. Err. Lower Conf. Limit Upper Conf.
Limit
Background 0 * * *
Beta(1) 0.283505 * * *
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-30.8119
-33.6778
-44.7464
# Param's Deviance Test d.f. P-value
6
1 5.73172 5 0.3332
1 27.869 5 <.0001
AIC:
69.3556
Log-likelihood Constant
27.33180844166138
Goodness of Fit
Scaled
Dose Est._Prob. Expected Observed Size Residual
149
p-a, a, a-T etrachl orotoluene
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0.0000
0.0000
0.000
0.000
26.000
0. 000
0.0280
0.0079
0.174
0.000
22.000
-0.419
0.0720
0.0202
0.566
0.000
28.000
-0.760
0.1800
0.0498
1.095
0.000
22.000
-1.073
0.4400
0.1173
3.401
6.000
29.000
1.500
1.1000
0.2679
7.769
7.000
29.000
-0.323
>
N)
II
N)
Ch
d.f. = 5
P-
-value = 0.
.5128
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.371636
BMDL = 0.2428 91
BMDU = 0.609459
Taken together, (0.242891, 0.609459) is a 90 % two-sided confidence
interval for the BMD
Multistage Cancer Slope Factor = 0.411707
MS_COMBO. (Version: 1.9; Date: 05/20/2014)
Input Data File:
C:\Users\JSWART\Desktop\BMDS\BMDS26\Data\SessionFiles\Fukuda_8_ms5.(d)
Gnuplot Plotting File:
C:\Users\JSWART\Desktop\BMDS\BMDS2 6\Data\SessionFiles\Fukuda_8_ms5.pit
Wed Mar 27 14:02:35 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
Dependent variable = Effect
Independent variable = Dose
Data file name = Fukuda_forestomach_carcinoma_in_situ.dax
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
150
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September 2019
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.0159495
Beta(1) = 0.114105
the user,
Beta(1)
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Background
have been estimated at a boundary point, or have been specified by
and do not appear in the correlation matrix )
Beta(1)
1
Parameter Estimates
Interval
Variable
Limit
Background
Beta(1)
Estimate
0
Std. Err.
0.164707 *
* - Indicates that this value is not calculated.
95.0% Wald Confidence
Lower Conf. Limit Upper Conf.
Model
Full model
Fitted model
Reduced model
AIC:
Analysis of Deviance Table
Log(likelihood)
-25.3477
-27.1465
-31.5546
56.293
Log-likelihood Constant
# Param's Deviance Test d.f.
6
1 3.59761 5
1 12.4138 5
21.370000104136281
P-value
0.6087
0.02954
Goodness of Fit
Dose
Est. Prob.
Expected
Observed
Size
Scaled
Residual
0.0000
0.0280
0.0720
0.1800
0.4400
1.1000
Chi^2 = 3.52
0.0000
0.0046
0.0118
0.0292
0.0699
0.1657
d.f. = 5
0.000 0.000 26.000
0.101 0.000 22.000
0.330 0.000 28.000
0.643 1.000 22.000
2.027 4.000 29.000
4.806 3.000 29.000
P-value = 0.62 08
0. 000
-0.319
-0.578
0. 452
1. 437
-0.902
Benchmark Dose Computation
Specified effect = 0.1
151
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September 2019
Risk Type = Extra risk
Confidence level = 0.95
BMD = 0.639685
BMDL = 0.37 62 69
BMDU = 1.33515
Taken together, (0.376269, 1.33515) is a 90 % two-sided confidence
interval for the BMD
Multistage Cancer Slope Factor = 0.265768
MS_COMBO. (Version: 1.9; Date: 05/20/2014)
Input Data File:
C:\Users\JSWART\Desktop\BMDS\BMDS26\Data\SessionFiles\Fukuda_8_ms5.(d)
Gnuplot Plotting File:
C:\Users\JSWART\Desktop\BMDS\BMDS2 6\Data\SessionFiles\Fukuda_8_ms5.pit
Wed Mar 27 14:02:35 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*doseAl) ]
The parameter betas are restricted to be positive
Dependent variable = Effect
Independent variable = Dose
Data file name = Fukuda_forestomach_multiple_papilloma.dax
Total number of observations = 4
Total number of records with missing values = 0
Total number of parameters in model = 2
Total number of specified parameters = 0
Degree of polynomial = 1
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.0342233
Beta(1) = 1.31428
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Background
152
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-------
FINAL
September 2019
have been estimated at a boundary point, or have been specified by
and do not appear in the correlation matrix )
Beta(1)
Beta (1) 1
the user,
Parameter Estimates
95.0% Wald Confidence
Interval
Variable Estimate Std. Err. Lower Conf. Limit Upper Conf.
Limit
Background 0 * * *
Beta(1) 1.85135 * * *
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
AIC:
Log(likelihood)
-29.9764
-30.5006
-34.416
63.0013
Log-likelihood Constant
# Param's Deviance Test d.f.
4
1 1.04855 3
1 8.87918 3
25.547993778159679
P-value
0.7895
0. 03094
Dose
Est. Prob.
Goodness of Fit
Expected
Observed
Size
Scaled
Residual
0.0000
0.0280
0.0720
0.1800
Chi^2 =1.17
0.0000
0.0505
0.1248
0.2834
d.f. = 3
0.000 0.000 26.000
1.111 2.000 22.000
3.494 4.000 28.000
6.235 5.000 22.000
P-value = 0.7594
0. 000
0. 865
0.289
-0.584
Benchmark Dose Computation
Specified effect
Risk Type
Confidence level
BMD
BMDL
BMDU
0.1
Extra risk
0. 95
0.0569101
0.0359441
0.138961
Taken together, (0.0359441, 0.138961) is a 90
interval for the BMD
two-sided confidence
153
p-a, a, a-T etrachl orotoluene
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September 2019
Multistage Cancer Slope Factor = 2.7821
MS_COMBO. (Version: 1.9; Date: 05/20/2014)
Input Data File:
C:\Users\JSWART\Desktop\BMDS\BMDS26\Data\SessionFiles\Fukuda_8_ms5.(d)
Gnuplot Plotting File:
C:\Users\JSWART\Desktop\BMDS\BMDS2 6\Data\SessionFiles\Fukuda_8_ms5.pit
Wed Mar 27 14:02:35 2019
BMDS Model Run
The form of the probability function is:
P[response] = background + (1-background)*[1-EXP(
-betal*dose/sl-beta2*dose/s2) ]
The parameter betas are restricted to be positive
Dependent variable = Effect
Independent variable = Dose
Data file name = Fukuda_skin_sguamous_cell_carcinoma.dax
Total number of observations = 6
Total number of records with missing values = 0
Total number of parameters in model = 3
Total number of specified parameters = 0
Degree of polynomial = 2
Maximum number of iterations = 5 00
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0
Beta(l) = 0
Beta(2) = 0.158724
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -Background -Beta(l)
have been estimated at a boundary point, or have been specified by
the user,
and do not appear in the correlation matrix )
Beta(2)
Beta (2) 1
Parameter Estimates
95.0% Wald Confidence
Interval
154
p-a, a, a-T etrachl orotoluene
-------
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September 2019
Variable Estimate Std. Err. Lower Conf. Limit Upper Conf.
Limit
Background 0 * * *
Beta(1) 0 * * *
Beta(2) 0.129953 * * *
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-13.3311
-14.2549
-22.1211
# Param's Deviance Test d.f. P-value
6
1 1.8477 5 0.8698
1 17.58 5 0.003522
AIC:
30.5099
Log-likelihood Constant
11.684817826274118
Goodness of Fit
Dose
Est. Prob.
Expected
Observed
Size
Scaled
Residual
0.0000
0.0280
0.0720
0.1800
0.4400
1.1000
Chi^2 =1.02
0.0000
0.0001
0.0007
0.0042
0. 0248
0.1455
d.f. = 5
0.000 0.000 26.000
0.002 0.000 22.000
0.019 0.000 28.000
0.092 0.000 22.000
0.721 0.000 29.000
4.220 5.000 29.000
P-value = 0.9608
0. 000
-0.047
-0.137
-0.305
-0.860
0.411
Benchmark Dose Computation
Specified effect
Risk Type
Confidence level
BMD
BMDL
BMDU
0.1
Extra risk
0. 95
0.90042
0.6485
1.36941
Taken together, (0.6485 , 1.36941) is a 90
interval for the BMD
two-sided confidence
Multistage Cancer Slope Factor =
0.154202
**** Start of combined BMD and BMDL Calculations.****
Combined Log-Likelihood -291.39612823909221
Combined Log-likelihood Constant 240.2577793819473
155
p-a, a, a-T etrachl orotoluene
-------
Benchmark Dose Computation
Specified effect
Risk Type
Confidence level
BMD
BMDL
0.1
Extra risk
0. 95
0.0186741
0.0148245
FINAL
September 2019
Multistage Cancer Slope Factor =
6.74558
156
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September 2019
APPENDIX D. REFERENCES
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