United States
Environmental Protection
1=1 m m Agency
EPA/690/R-12/033F
Final
11-14-2012
Provisional Peer-Reviewed Toxicity Values for
/>-Toluidine
(CASRN 106-49-0)
Superfund Health Risk Technical Support Center
National Center for Environmental Assessment
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268

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AUTHORS, CONTRIBUTORS, AND REVIEWERS
CHEMICAL MANAGER
J. Phillip Kaiser, PhD
National Center for Environmental Assessment, Cincinnati, OH
DRAFT DOCUMENT PREPARED BY
ICF International
9300 Lee Highway
Fairfax, VA 22031
PRIMARY INTERNAL REVIEWERS
Ambuja Bale, PhD, DABT
National Center for Environmental Assessment, Washington, DC
Anuradha Mudipalli, MSc, PhD
National Center for 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 contents of this document may be directed to the U.S. EPA Office of
Research and Development's National Center for Environmental Assessment, Superfund Health
Risk Technical Support Center (513-569-7300).
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TABLE OF CONTENTS
COMMONLY USED ABBREVIATIONS	iv
BACKGROUND	1
DISCLAIMERS	1
QUESTIONS REGARDING PPRTVs	1
INTRODUCTION	2
REVIEW OF POTENTIALLY RELEVANT DATA (CANCER AND NONCANCER)	4
HUMAN STUDIES	7
Oral Exposures	7
Inhalation Exposures	7
ANIMAL STUDIES	7
Oral Exposure	7
Inhalation Exposure	11
OTHER DATA (SHORT-TERM TESTS, OTHER EXAMINATIONS)	14
Genotoxicity Studies	14
Acute Toxicity Studies	15
Metabolism/Toxicokinetic Studies	15
Mechanistic/Mode of Action Studies	15
DERIVATION 01 PROVISIONAL VALUES	16
DERIVATION OF ORAL REFERENCE DOSES	17
Derivation of Subchronic Provisional RfD (Subchronic p-RfD)	17
Derivation of Chronic Provisional RfD (Chronic p-RfD)	17
DERIVATION OF INHALATION REFERENCE CONCENTRATIONS	17
CANCER WEIGHT-OF-EVIDENCE DESCRIPTOR	17
MODE-OF -ACTION DISCUSSION	18
DERIVATION OF PROVISIONAL CANCER POTENCY VALUES	19
Derivation of Provisional Oral Slope Factor (p-OSF)	19
Derivation of Provisional Inhalation Unit Risk (p-IUR)	20
APPENDIX A. PROVISIONAL SCREENING VALUES	21
APPENDIX B. DATA TABLES	25
APPENDIX C. BENCHMARK DOSE (BMD) CALCULATIONS and BMD MODELS	26
APPENDIX D. REFERENCES	33
in
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COMMONLY USED ABBREVIATIONS
BMC
benchmark concentration
BMCL
benchmark concentration lower bound 95% confidence interval
BMD
benchmark dose
BMDL
benchmark dose lower bound 95% confidence interval
HEC
human equivalent concentration
HED
human equivalent dose
IUR
inhalation unit risk
LOAEL
lowest-observed-adverse-effect level
LOAELadj
LOAEL adjusted to continuous exposure duration
LOAELhec
LOAEL adjusted for dosimetric differences across species to a human
NOAEL
no-ob served-adverse-effect level
NOAELadj
NOAEL adjusted to continuous exposure duration
NOAELrec
NOAEL adjusted for dosimetric differences across species to a human
NOEL
no-ob served-effect level
OSF
oral slope factor
p-IUR
provisional inhalation unit risk
POD
point of departure
p-OSF
provisional oral slope factor
p-RfC
provisional reference concentration (inhalation)
p-RfD
provisional reference dose (oral)
RfC
reference concentration (inhalation)
RfD
reference dose (oral)
UF
uncertainty factor
UFa
animal-to-human uncertainty factor
UFC
composite uncertainty factor
UFd
incomplete-to-complete database uncertainty factor
UFh
interhuman uncertainty factor
UFl
LOAEL-to-NOAEL uncertainty factor
UFS
subchronic-to-chronic uncertainty factor
WOE
weight of evidence
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PROVISIONAL PEER-REVIEWED TOXICITY VALUES FOR
/7-TOLUIDINE (CASRN 106-49-0)
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 a standing panel of National
Center for Environment Assessment (NCEA) scientists and an independent external peer review
by 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.
The PPRTV review process provides needed toxicity values in a quick turnaround
timeframe while maintaining scientific quality. PPRTV assessments are updated approximately
on a 5-year cycle for new data or methodologies that might impact the toxicity values or
characterization of potential for adverse human health effects and are revised as appropriate. It is
important to utilize the PPRTV database flittp://hhpprtv.ornl.gov) to obtain the current
information available. When a final Integrated Risk Information System (IRIS) assessment is
made publicly available on the Internet (littp://www.epa.gov/iris). the respective PPRTVs are
removed from the database.
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. Environmental Protection Agency (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.
QUESTIONS REGARDING PPRTVs
Questions regarding the contents and appropriate use of this PPRTV assessment should
be directed to the EPA Office of Research and Development's National Center for
Environmental Assessment, Superfund Health Risk Technical Support Center (513-569-7300).
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INTRODUCTION
/>Toluidine occurs as white or colorless leaflets or lustrous plates with an aromatic odor
and burning taste (HSDB, 2009). Its major uses include the manufacture of dyes (basic red 9 and
acid green 25); organic synthesis; reagent for lignin, nitrite, and phloroglucinol; and the
preparation of ion exchange resins. Occupational exposure to /Moluidine may occur through
inhalation and dermal contact with this compound at workplaces where /Moluidine is produced
or used. The general population may be exposed to /Moluidine via inhalation of ambient air and
tobacco smoke, ingestion of contaminated food and drinking water, and/or dermal contact with
this compound. The empirical formula for /Moluidine is C7H9N, and the molecular structure of
/Moluidine is presented in Figure 1. Some physicochemical properties of /Moluidine are
provided in Table 1.
ch3
Figure 1. /7-Toluidine Structure
Table 1. Physicochemical Properties for />-Toluidinea
Property (unit)
Value
Boiling point (C)
200.4
Melting point (C)
44-45
Density (g/cm3 at 20C)
0.9619
Vapor pressure (mm Hg at 25C)
0.286
pH (unitless)
Not available
Solubility in water (g/L at 20C)
6.64
Relative vapor density (air =1)
3.9
Molecular weight (g/mol)
107.16
Octanol/water partition coefficient (log Kow, unitless)
1.39
aValues were obtained from HSDB (2009).
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No reference dose (RfD), reference concentration (RfC), or cancer assessment for
/Moluidine is included in the IRIS database (U.S. EPA, 2010a) or on the Drinking Water
Standards and Health Advisories List (U.S. EPA, 2009). The HEAST (U.S. EPA, 2010b) reports
an OSF of 0.19 per mg/kg-day and an oral unit risk of 5.4 x 10~6 per |ig/L. These values were
based on liver tumors following dosing for 18 months in the mouse. A PPRTV document also
exists for /Moluidine (U.S. EPA, 2002) examining the potential derivation of a chronic p-RfD.
The 2002 PPRTV states that a p-RfD could not be derived for /Moluidine due to the lack of
human data and inadequate animal data. Since that time a new subchronic study has become
available (Jodynis-Liebert, 2005). For this reason, the database for this chemical has been
reviewed.
The CARA list (U.S. EPA, 1994) includes a Health and Environmental Effects Profile
(HEEP) for /Moluidine (U.S. EPA, 1985). The toxicity of /Moluidine has not been reviewed by
ATSDR (2008). The toxicity of /Moluidine has not been reviewed by the World Health
Organization (WHO, 2010). CalEPA (2008, 2010) has not derived toxicity values for exposure
to /Moluidine. The American Conference of Governmental Industrial Hygienists (ACGIH,
2010) reports a threshold limit value (TLV) of 2 ppm, 8.8-mg/m3 time-weighted average (skin).
The Occupational Safety and Health Administration (OSHA, 2010) reports a vacated permissible
exposure limit (PEL) of 2 ppm, 8.8-mg/m3 time-weighted average (skin). Both the TLV and
PEL are based on a calculated permeability coefficient for o-toluidine (U.S. EPA, 1992). The
National Institute of Occupational Safety and Health (NIOSH, 2010) identifies /Moluidine as a
potential carcinogen and recommends that occupational exposures to carcinogens be limited to
the lowest feasible concentration.
The HEAST (U.S. EPA, 2010b) reports an OSF of 0.19 per mg/kg-day for /Moluidine
based on liver tumors in CD-I mice exposed to /Moluidine in the diet at 1000 or 2000 ppm for
6 months followed by 12 months on a 500- or 1000-ppm diet, respectively (Weisburger et al.,
1978). The International Agency for Research on Cancer (IARC, 2010) has not reviewed the
carcinogenic potential of /Moluidine. />Toluidine is not included in the National Toxicology
Program's 12th Report on Carcinogens (NTP, 2011). CalEPA (2008) has not derived a
quantitative estimate of carcinogenic potential for /Moluidine.
Literature searches were conducted on sources published from 1900 through July 2011
for studies relevant to the derivation of provisional toxicity values for /Moluidine (CAS
No. 106-49-0). Searches were conducted using EPA's Health and Environmental Research
Online (HERO) database of scientific literature. HERO searches the following databases:
AGRICOLA; American Chemical Society; BioOne; Cochrane Library; DOE: Energy
Information Administration, Information Bridge, and Energy Citations Database; EBSCO:
Academic Search Complete; GeoRef Preview; GPO: Government Printing Office;
Informaworld; IngentaConnect; J-STAGE: Japan Science & Technology; JSTOR: Mathematics
& Statistics and Life Sciences; NSCEP/NEPIS (EPA publications available through the National
Service Center for Environmental Publications [NSCEP] and National Environmental
Publications Internet Site [NEPIS] database); PubMed: MEDLINE and CANCERLIT databases;
SAGE; Science Direct; Scirus; Scitopia; SpringerLink; TOXNET (Toxicology Data Network):
ANEUPL, CCRIS, ChemlDplus, CIS, CRISP, DART, EMIC, EPIDEM, ETICBACK, FEDRIP,
GENE-TOX, HAPAB, HEEP, HMTC, HSDB, IRIS, ITER, LactMed, Multi-Database Search,
NIOSH, NTIS, PESTAB, PPBIB, RISKLINE, TRI, and TSCATS; Virtual Health Library; Web
of Science (searches Current Content database among others); World Health Organization; and
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Worldwide Science. The following databases outside of HERO were searched for health-related
values: ACGM, AT SDR, CalEPA, EPA IRIS, EPA HEAST, EPA HEEP, EPA OW, EPA
TSCATS/TSCATS2, NIOSH, NTP, OSHA, and RTECS.
REVIEW OF POTENTIALLY RELEVANT DATA
(CANCER AND NONCANCER)
Table 2 provides an overview of the relevant database for /Moluidine and includes all
potentially relevant repeated short-term-, subchronic-, and chronic-duration studies. NOAELs,
LOAELs, and BMDL/BMCLs are provided in HED/HEC units for comparison except that oral
noncancer values are not converted to HEDs and are identified in parentheses as (Adjusted)
rather than HED/HECs. Principal studies are identified. Entries for the principal studies are
bolded.
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Table 2. Summary of Potentially Relevant Data for />-Toluidine (CASRN 106-49-0)
Category
Number of
Male/Female, Strain,
Species, Study Type,
Study Duration
Dosimetry
Critical Effects
NOAEL
BMDL/
BMCL
LOAEL'
Reference (Comments)
Notesb
Human
1. Oral (mg/kg-day)
No studies were located.
2. Inhalation (mg/m3)
No studies were located.
Animal
1. Oral (mg/kg-day)
Subchronic
8/0, Wistar rat, dietary,
7 days/week, 1 or
3 months
0,40,80, or
160 for 1 or
3 months
Increased
methemoglobin content
in blood
N/A
No
adequate
BMD model
fits to data
40
Jodynis-Liebert and
Bennasir (2005); LOAEL
identified from a statistical
significant increase in
methemoglobin levels for
both exposure durations (i.e.,
1 or 3 months) and both diet
types (4 or 14% fat)
PS
PR
10/0, rat, dietary,
7 days/week, 28 days
0, 14, 67, or 126
Increased relative liver
weight
14
Not
performed
67
IBT (1973)
Information from ACGIH
(2001); the full primary
reference for this study is not
available
NPR
Chronic
0/8, Wistar rat, dietary
(24% or 8% protein),
7 days/week, 6 or
12 months
0,40,80, or
160
Increased
methemoglobin content
in blood, findings, clinical
signs, kidney and liver
effects, and decreased
body weight
N/A
Not
Performed
40
Malik-Brys and Senczuk
(1995a,b,c)
PS
PR
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Table 2. Summary of Potentially Relevant Data for />-Toluidine (CASRN 106-49-0)
Category
Number of
Male/Female, Strain,
Species, Study Type,
Study Duration
Dosimetry
Critical Effects
NOAEL
BMDL/
BMCL
LOAEL3
Reference (Comments)
Notesb
Developmental
None
Reproductive
None
Carcinogenicity
25/0, Crl:CDBL rat,
dietary, 7 days/week,
18 months exposure
followed by 6 months
control diet prior to
sacrifice
0, 20, or 40
No increase in tumors was
observed
N/A
Not
performed
N/A
Weisburger et al. (1978a)
PR
Carcinogenicity
25/25, CD-I mouse,
dietary, 7 days/week,
18 months followed by
3 months control diet
prior to sacrifice
0,15, or 30
Incidences of liver
tumors in male mice
were increased in both
treated groups (47-50%)
compared to concurrent
controls (17%)
N/A
Male: 3
Female: 8.3
N/A
Weisburger et al. (1978b)
PS
PR
2. Inhalation (mg/m3)
No studies were located.
aNot reported by the study author but determined from data.
dosimetry: NOAEL, BMDL/BMCL, and LOAEL values are converted to an adjusted daily dose (ADD in mg/kg-day) for oral noncancer effects and a human equivalent
dose (HED in mg/kg-day) for oral carcinogenic effects. All long-term exposure values (4 weeks and longer) are converted from a discontinuous to a continuous (weekly)
exposure. HEDn = (avg. mg test article ^ avg. kg body weight ^ number daily dosed)14.
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HUMAN STUDIES
Oral Exposures
No oral studies were found on the subchronic, chronic, developmental, or reproductive
toxicity or on the carcinogenicity of /Moluidine in humans.
Inhalation Exposures
No inhalation studies were found on the subchronic, chronic, developmental, or
reproductive toxicity or on the carcinogenicity of /Moluidine in humans.
ANIMAL STUDIES
Oral Exposure
The effects of oral exposure of animals to /Moluidine were evaluated in two
sub chronic-duration studies: Jodynis-Liebert and Bennasir (2005) and IBT (1973) and one
chronic-duration study: Malik-Brys and Senczuk (1995).
Subchronic-duration Studies
Jodynis-Liebert and Bennasir (2005) is selected as the principal study for deriving
the screening subchronic p-RfD. In this peer-reviewed study, /Moluidine (99.7% purity) was
administered in the diet to eight male Wistar rats/dose group/diet type at nominal doses of 0, 40,
80, and 160 mg/kg-day1 for 1 or 3 months. Two diet types were used: /Moluidine was mixed
with standard diet (4% fat) or standard diet supplemented with 10% sunflower oil (14% fat).
The animals were obtained from the University of Medical Sciences in Poznan, Poland, and
housed under acceptable conditions. This study also evaluated the toxicity of (Moluidine and
w-toluidine; however, the results from those tests are not germane to this report. The content of
toluidines in the diet and homogeneity were determined every 2 weeks. The stability of the
compound in the diet under test conditions was not reported. Body weight, food consumption,
and water consumption were measured every third day. Rats were placed in metabolic cages
every week (1-month treatment) or 2 weeks (3-month treatment), and urine was collected over
24 hours for quantification of the toluidines by gas chromatography. Rats were euthanized via
cardiac puncture under narcotan anesthesia, and blood was collected. Plasma was separated, and
livers were perfused with cold 1.15% KC1. Liver samples were stored at -70C until analyzed.
Liver homogenates were prepared for the lipid peroxidation assay. A marker of lipid
peroxidation, malondialdehyde concentration, was measured in the liver by the thiobarbituric
acid reactive substances (TBARS) assay. From the blood, methemoglobin (MetHb), serum
alanine aminotransferase (ALT), aspartate aminotransferase (AST), sorbitol dehydrogenase
(SDH), and blood urea nitrogen (BUN) concentrations were measured, as was hepatic
glutathione. Gross or histological pathology was not performed. Statistical analyses were
performed using analysis of variance and Student's Mest, or the Kruskal-Wallis and
Newman-Keuls tests if the variances were not homogeneous. Treated groups were compared to
controls, and the two types of diet were compared to each other. Differences with /^-values of
0.01 or less were reported as statistically significant.
The study authors stated that there were no remarkable changes in the general appearance
of the rats (Jodynis-Liebert and Bennasir, 2005). Treatment-related effects were observed in this
study and are described below. The mean body-weight gain for the 3-month study was
decreased by 2931%, 2127%, and 62-80% at 40, 80, and 160 mg/kg-day, respectively.
1 Doses were provided in Jodynis-Liebert and Bennasir (2005).
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Body-weight losses were infrequently observed at 160 mg/kg-day. The study authors stated that
similar effects were noted in the 1-month study animals. Methemoglobin content was increased
(p < 0.01) by 113-843% in all treated groups (see Table B.l). Typically, the increases were
similar at 40 and 80 mg/kg-day, and increases were greater in magnitude at 160 mg/kg-day.
Increases in MetHb content were also statistically significantly greater (p < 0.01) in the standard
diet groups compared to the high-fat diet groups at the two highest dose groups. Reduced
glutathione (GSH) concentrations in the liver were increased by 90-233% in all treated groups.
In the high-fat diet groups, the magnitude of the increase was greatest at 40 mg/kg-day and least
at 160 mg/kg-day (seemingly unrelated to dose). In the standard diet groups, the magnitude of
increase was similar at 40 and 80 mg/kg-day, but higher at 160 mg/kg-day. The GSH content in
liver between the different diets (based on fat content) differed significantly (p < 0.01) at 40 and
160 mg/kg-day. Lipid peroxidation (nmol TBARS/g tissue) was increased (not statistically
significant) in the 160 mg/kg-day, high-fat, 3-month group by 24% and was increased (p < 0.01)
by 65-352%) in the other treated groups. A dose-related effect was only obvious in the standard
diet, 1-month group. In the other groups, lipid peroxidation levels were similar at 40 mg/kg-day
to 80 mg/kg-day but were less at 160 mg/kg-day. Serum ALT levels were generally increased,
but the effects were unrelated to dose and not sufficient to be indicative of a biologically adverse
effect. Levels of serum AST, SDH, and BUN were similar to controls.
It was not stated if stability of the /Moluidine in the diet was confirmed or whether this
study was conducted according to Good Laboratory Practice (GLP) standards (40 CFR Part 160;
Jodynis-Liebert and Bennasir, 2005). However, this study supports the development of a p-RfD
because of the well documented and scientifically acceptable nature of the publication. The
LOAEL for Jodynis-Liebert and Bennasir (2005) is identified to be 40 mg/kg-day for
significantly increased methemoglobin content in blood; no NOAEL is identified.
An unpublished study by IBT (1973) administered /Moluidine (purity not reported) in the
diet to 10 male rats (strain not reported) per dose group at nominal doses of 0, 14, 67, or
126 mg/kg-day for 4 weeks. Decreased body-weight gain was noted at 126 mg/kg-day, and
significantly increased relative liver weights were observed at 67 and 126 mg/kg-day. The full
primary reference for this study is not available. In limited microfiche copies of this reference,
few data were reported, no explanation of study design was given, and the data tables are barely
legible, making this study unusable for derivation of a subchronic p-RfD. Additional data from
this study were provided in the review by ACGIH (2001).
Chronic-duration Studies
Malik-Brys and Senczuk (1995a,b,c) is selected as the principal study for deriving
the screening chronic p-RfD. In this peer-reviewed study, young female Wistar rats were
divided into 14 experimental groups. Each toluidine isomer (ortho, meta, or para) was
administered separately in the diet at 0, 40, 80, 160 mg/kg-day to 8 rats/group for periods of
6 months or at 160 mg/kg-day for 12 months. Dietary administration (unknown purity of
compound) was via a 24% protein diet (standard diet) or 8% protein diet. This study was
designed to examine the impact of dietary protein levels on blood and urine concentrations of the
test chemicals, and the effects of the test chemicals and dietary protein on blood and liver
activities of certain enzymes, body weights, clinical signs, and histological findings. It is
unknown if the study was performed under GLP standards. Urine was collected in metabolic
cages for 24 hours after compound administration. Blood was collected from the rats' hearts
1 hour after o- and w-toluidine were administered, and 2 hours after /Moluidine was
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administered, which corresponds to the maximal concentration of the compounds in the blood.
Toluidine was isolated from the blood and urine samples by chloroform extraction, and toluidine
concentrations were determined by gas chromatography. The methemoglobin content in the
same blood samples was assayed by spectrophotometry. Measurements of the following blood
serum enzymes' activity were also taken using commonly known methods: aniline hydroxylase,
amidopyrine demethylase, and P-glucuronidase. Morphological evaluation of the blood was also
performed. Complete hemograms of the blood collected from animals exposed to toluidine and
from the control animals were also performed. The levels of hemoglobin, erythrocytes,
leukocytes, hematocrit, thrombocytes, and reticulocytes were measured. The results obtained
were statistically analyzed using the Student, Cochran-Cox, or Duncan tests.
After 6 months of dietary exposure to ^-toluidine, the methemoglobin content was
reported by the study authors to be statistically significantly increased in animals at all doses
tested compared to the control animals (Malik-Brys and Senczuk, 1995a,b,c). An increase in
^-toluidine concentration in blood and urine was noted as the administered dose increased.
Treatment at 40, 80, and 160 mg/kg-day in the 8% protein diets resulted in 2.2%, 6.7%, and
10.5%) methemoglobin, respectively. Treatment at 40, 80, and 160 mg/kg-day in the 24% protein
diets resulted in approximately 4.7%, 7.0%>, and 10.4%> methemoglobinemia, respectively.
Methemoglobin values in controls were 0.8%>. Significant decreases in the quantity of
thrombocytes, erythrocytes, and leukocytes were observed, as well as an increase in the number
of reticulocytes (actual data not reported).
Treatment with /Moluidine (Malik-Brys and Senczuk, 1995a,b,c) in the 8%> protein diet
(dose level not reported) resulted in the following effects compared to treatments in the
24%) protein diet: less toluidine in the blood, less toluidine in the urine, and differential effects in
MetHb values compared to those presented above. The following findings were listed for the
8%> protein dietary formulations but were not listed for the 24% protein dietary formulations:
limb paresis, convulsion, alopecia, blood in the urine, frequent falls, increased P-glucuronidase in
liver (not dose- or time-dependent), and increased analine hydroxylase (not dose-dependent, but
time-dependent; unknown toxicological significance). Treatment at 160 mg/kg-day in the
8%> protein diet for 12 months resulted in the following kidney findings: inflammation of the
parenchyma, hyaline droplet degeneration, homogeneous protein masses, congestive cysts, and
dystrophic calcification. Treatment (dose not reported) in the 8%> protein diet treatment group
also resulted in adrenal neutrophilic adenomas, which the study authors stated were associated
with the decreased protein content in the feed and probably had no relationship with the effects
of /^-toluidine. Liver effects were noted in animals from both diets (doses not specified) but were
most evident in animals receiving the 8%> protein diet. These effects included enlarged portal
area, necrosis, focal steatosis, infiltration of lymphocyte-like mononuclear cells, and
multiplication of nuclei. Decreased body weights were noted with treatment in both diets. In the
24%) protein diet, decreased thrombocytes, erythrocytes, leukocytes, and reticulocytes were
observed, but the actual doses at which the effects were noted were not reported.
Although the study by Malik-Brys and Senczuk (1995a,b,c) does not present quantitative
data, only a bar graph, for any effects due to ^-toluidine, the study authors do report statistical
significant changes. Specifically, a dose-related increase in methemoglobin blood levels due to
^-toluidine was noted to be statistically significant at all doses tested following 6 months of
/^-toluidine exposure in the diet. Because data were not presented and means with standard
deviations were not reported, benchmark dose modeling of treatment-related effects is not
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possible. However, a LOAEL of 40 mg/kg-day can be identified from this study based on
statistically significant increases in methemoglobin levels after 6 months dietary treatment of
/Moluidine. Because 40 mg/kg-day is the lowest dose tested, a NOAEL cannot be identified.
Developmental and Reproductive Studies
No studies could be located regarding the effects of /Moluidine on development and reproduction
in animals.
Carcinogenicity Studies
In a peer-reviewed study, Weisburger et al. (1978a) administered /Moluidine
(>97% purity) in the diet to 25 male Sprague-Dawley rats/dose group at nominal doses of 1000
or 2000 mg/kg dietary concentration for 18 months. Animals were maintained on control diets
for an additional 6 months prior to study termination. The calculated human equivalent doses are
20	and 40 mg/kg-day.2 Many other compounds were similarly tested in this study, but the results
from these tests are not discussed because these chemicals are not the subject of this report. A
necropsy was performed on all animals that survived at least 6 months on test and/or were
euthanized at the end of the experimental period. Histological examination was done on all
grossly abnormal organs, tumor masses, lung, liver, spleen, kidney, adrenal, heart, bladder,
stomach, intestines, reproductive organs, and pituitary glands. Statistical analysis of tumor data
was performed using the Fisher's Exact Test. Two control groups were used: a matched control
group (by sex and compound) that was conducted concurrently with the treated animals and a
pooled control group, which included the control data for all tested compounds grouped by sex.
Tumors in treated groups with /^-values of 0.05 or less for both matched and pooled controls
were deemed statistically significant. The study authors stated that the primary goal of the study
was to assess the possible carcinogenic effect of these compounds; nonneoplastic degenerative or
inflammatory lesions were recorded when they occurred but were only mentioned when
considered treatment related. Other parameters (such as body-weight gain and clinical
chemistry) were not reported. No nonneoplastic findings were reported for /Moluidine, and no
treatment-related neoplastic findings were observed in the male rat.
The mouse study by Weisburger et al. (1978b) is selected as the principal study for
deriving the provisional oral slope factor (p-OSF). In a peer-reviewed study,
Weisburger et al. (1978b) administered /Moluidine (>97% purity) in the diet to 25 CD-I
mice/sex/dose group at nominal doses of 1000 or 2000 mg/kg dietary concentration for
6 months. The mice were treated an additional 12 months with lowered doses of 500- or
1000-mg/kg dietary concentration. Animals were maintained on control diets for an additional
3 months prior to study termination. The nominal time-weighted-average total dietary
concentrations are 571 mg/kg ([(1000 mg/kg x 6 months) + (500 mg/kg x 12 months)]
21	months total) and 1143 mg/kg ([(2000 mg/kg x 6 months) + (1000 mg/kg x 12 months)]
21 months total). The nominal time-weighted-average human equivalent doses are 15 and
2Human Equivalent Dose = Feed Concentration x Food Consumption per Day x (1 -f- Body Weight) x
(Months Dosed ^ Total Months) x |BW(imm(l ^ BW|lllnl(IM|0 2\ where body weights used were from EPA's (1994b)
chronic values for male Sprague-Dawley Rats (0.523 kg) and where feed intakes used were from EPA's (1988)
chronic values for male Sprague-Dawley Rats (0.036 kg) and where BWt,, (70 kg) was obtained from EPA's
Exposure Factors Handbook (1997); Months Dosed was 18, and Total Months was 24.
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30 mg/kg-day.3 Histological examination of pituitary glands was not performed, but other
details of methodology were as described above for rats (Weisburger et al., 1978a).
No nonneoplastic findings were reported for /Moluidine (Weisburger et al., 1978b). In
male mice, the incidences of liver tumors were increased in the treated groups (47-50%)
compared to the concurrent control (17%) and the pooled controls for the entire study (7%;
see Table B.2). The difference was significant in the low dose compared to the pooled controls
(p < 0.025) and in the high dose compared to both the simultaneous and the pooled controls
(p < 0.05). In female mice, the incidences of liver tumors were increased in the treated groups
(10-18%)) compared to the simultaneous control (0%>) or the pooled controls for the entire study
(P/o). The difference was significant at the high dose compared to only the pooled controls
(p < 0.025). No information was provided regarding age of tumor onset.
It is unclear if this study (Weisburger et al., 1978a,b) was conducted according to GLP
standards (40 CFRPart 160; November 26, 1983). Only limited details of the animal husbandry
were provided: mice were housed up to 5 animals per plastic cage, and rats were housed up to
3 animals per cage, and the temperature was maintained at 23  2C. The stability of the
/Moluidine in the diet was tested; however, it was not stated if homogeneity and concentration
analyses were performed for the dietary formulations. It was not clear exactly which parameters
(e.g., hematology, clinical chemistry, histology) were evaluated, and the study authors did not
report results of these evaluations if they did not consider them related to treatment. The focus
of this study was the incidence of neoplastic lesions. The type and incidence of each liver tumor
were not reported nor was mean time-to-tumor onset. The actual time-weighted-average intakes
were also not reported.
Inhalation Exposure
No inhalation studies were found on the subchronic, chronic, developmental, or
reproductive toxicity or carcinogenicity of /Moluidine in animals.
3Human Equivalent Dose = Time-Weighted Food Concentration x Food Consumption per Day x (1 -f- Body Weight)
x [BWammai^- BWhuman]0 25, where body weights used were from EPA's (1994) chronic values by averaging the body
weights for the total female and male mouse strains (0.030225 kg) and where feed intakes used were from EPA's
(1988) chronic values by averaging the feed intakes for the total female and male mouse strains (0.0055 kg) and
where BWhuman (70 kg) was obtained from EPA's Exposure Factors Handbook (1997).
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Table 3. Other Studies
Test
Materials and Methods
Results
Conclusions
References
Genotoxicity
Male Crl:CDBR rats were treated by gavage with
500-mg/kg radiolabeled toluidine in corn oil. Rats were
treated with either o- or /Moluidinc and sacrificed
(4-5 rats/time point) at various times up to 48 hours
postdose. Liver samples were prepared for quantitation of
DNA, RNA, and total protein binding. Additionally,
blood samples were obtained at various time points up to
72 hours postdose from another group of rats to determine
plasma kinetics. Various tissues were sampled at
termination to determine tissue distribution of
radioactivity.
DNA, RNA, and total protein binding
occurred and were more prominent with
/Moluidinc than o-toluidine. The plasma
elimination half-life was approximately
12-15 hours. Highest tissue concentrations
of /Moluidinc residues were found in liver,
kidney, skin, and fat.
DNA-binding occurs
indicating that /Moluidinc
may be an initiator.
Brock et al. (1990)
Genotoxicity
An in vitro chemical hydroxylation system (Udenfriend)
was used to evaluate the genotoxicity of breakdown
products of /Moluidinc in Saccharomyces cerevisiae.
The resulting breakdown products of
/Moluidinc incubated in Udenfriend
hydroxylation medium induced reciprocal
recombination in diploid strain D-3 but not in
the parent compound.
The study author suggests
that iV-hydroxylation of
/Moluidinc in vivo may
result in bioactivation to a
carcinogenic product.
Mayer (1977)
Genotoxicity
In vitro mutagenicity tests were performed in Salmonella
typhimurium strains TA1535 and TA1538. The
DNA-modifying capacity was determined with normal and
DNA polymerase-deficient Escherichia coli.
Induction of mutations and
DNA-modificationby /Moluidinc were not
noted.
/>-Toluidinc genotoxicity
was negative in these
tested systems.
Rosenkranz and
Poirier (1979)
Genotoxicity
This report summarizes the genotoxicity of /Moluidinc.
Tests were performed i n ,V. typhimurium, E. coli,
S. cerevisiae, primary rat hepatocytes, Chinese hamster
lung fibroblasts, and other test systems.
The summarized results regarding /Moluidinc
genotoxicity were generally negative.
/>-Toluidinc was generally
negative in these tested
systems.
ACGIH (2001)
Acute
Toxicity
This report summarizes the acute effects of /Moluidinc in
humans and animals.
LD50 values for /Moluidinc in the rat, mouse,
and rabbit were reported. It was an ocular
and upper respiratory irritant in a rat
inhalation study, and a dermal sensitizer in a
guinea pig study. />-Toluidinc intoxication
results in methemoglobinemia and hematuria
in humans.
The acute toxicity is slight
compared to other toxic
compounds.
ACGIH (2001)
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Table 3. Other Studies
Test
Materials and Methods
Results
Conclusions
References
Metabolism
A single oral dose of 500-mg/kg /Moluidinc was
administered to male S-D rats (n = 4), and urine was
collected for 24 hours. Metabolites were isolated and
identified.
Parent compound represented only 2.5% of
the dose, and a single metabolite was
identified.
Metabolism proceeds
mainly through ring
hydroxylation with
subsequent conjugation.
Cheever et al.
(1980)
Mode of
action
/>-Toluidinc was administered in sunflower oil
(76 mg/kg-day) by intraperitoneal injection for
3 consecutive days to male Wistar rats. Microsome
enzyme activities were measured from liver, kidney, and
lung samples.
The major effects included increased epoxide
hydrolase (t 172%) and glutathione
S-transferase (|53%) activities.
The compound affects the
activity of metabolic
enzymes.
Gnojkowski et al.
(1984)
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OTHER DATA (SHORT-TERM TESTS, OTHER EXAMINATIONS)
Genotoxicity Studies
The following studies on the genotoxicity and mutagenicity of /Moluidine are listed and
summarized in Table 3. Brock et al. (1990) administered 500-mg/kg/;-[ring-U-l4C] toluidine in
corn oil by gavage to male Crl:CDBR rats. Rats were sacrificed at 4, 8, 12, 24, or 48 hours
after dosing (4-5 rats at each time point), and the livers were excised and homogenized.
Samples were prepared for the quantitation of DNA, RNA, and total protein binding.
Additionally, jugular-vein cannulas were inserted into male rats, and oral doses of the
radiolabeled compounds in corn oil/methanol (8:2, v/v) were administered on the day following
surgery. Blood samples were drawn from each of four rats via the cannula at 30 minutes and 2,
6, 12, 24, 36, 48, and 72 hours. Rats were euthanized, and selected organs and tissues were
excised. Radioactive residues were quantified in the samples. Peak blood levels of radioactivity
were observed at 12 hours, and the plasma elimination half-life was approximately 12-15 hours.
The highest concentrations of radioactive residues were found in the liver, kidneys, subcutaneous
abdominal fat, and abdominal skin (15.5-26.4 |ig Eq./g). /?-Toluidine was found to bind to
DNA, RNA, and total protein.
Mayer (1977) used an in vitro chemical hydroxylation system (i.e., Udenfriend) to
evaluate the genotoxicity of breakdown products of ^-toluidine. A diploid strain of S. cerevisiae
designated D-3 was used. Cells were suspended in the reaction mixture with /^-toluidine at
1 mg/mL in an oxygen or nitrogen atmosphere. It was found that the resulting breakdown
products in the oxygen atmosphere induced reciprocal mitotic recombination, while the parent
compound in the nitrogen atmosphere did not. The study authors suggest that A'-hydroxylation
of ^-toluidine in vivo may result in bioactivation to a carcinogenic product.
Rosenkranz and Poirier (1979) evaluated the mutagenicity of 99 chemicals in standard
S. typhimurium assays with and without S9 using strains TA1535 and TA1538. The
DNA-modifying capacity was determined with normal and DNA polymerase-deficient E. coli
strains. /^-Toluidine did not induce mutations or cause DNA modification.
The ACGIH (2001) report detailed the acute toxicity of /Moluidine, which is briefly
summarized as follows. Evidence was negative for a role of para-toluidine in the induction of
mutation in Salmonella typhimurium strains G46, TA1535, TA1537, TA1538, TA98, or TA100
or in Escherichia coli strains WP2, WP2 uvrA, C3076, and D3052 when tested in the absence or
presence of rat a liver activation (S9) system. In Saccharomyces cerevisiae strains D3 and D4,
^-toluidine did not induce mitotic crossing-over or mitotic recombination. Employing a
modified E. coli DNA repair test (pol A7A+), 5-|ig/ml /Moluidine was not mutagenic in the
absence or presence of an exogenous metabolic activation system (Rozenkranz and Poiner,
1979). In the presence of induced rat liver microsomes, /Moluidine attenuated unscheduled
DNA synthesis in primary rat hepatocytes (Thompson et al., 1983) and was also shown at a
concentration of 10 mm for 2 hours to not increase single-strand DNA breaks in Chinese hamster
lung fibroblasts (Zimmer et al., 1980). In male Swiss CD-I mice, a dose of 35 mg/kg body
weight delivered via intraperitoneal injection increased single-strand hepatic and renal DNA
breaks (Cesarone et al., 1982). Testicular DNA synthesis was inhibited in male Swiss CD-I
mice following oral intubation of /Moluidine at a dose of 200-mg/kg body weight (Seiler, 1977).
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Acute Toxicity Studies
The ACGIH (2001) report detailed the acute toxicity of /Moluidine, which is briefly
summarized as follows. Clinical signs of /Moluidine exposure in humans included
methemoglobinemia and hematuria. />Toluidine has been shown to be absorbed via the
respiratory tract and skin (Scott et al., 1983), and prolonged exposure to as little as 10 ppm of a
toluidine mixture was reported to cause symptoms of illness (Goldblatt, 1955). The oral LD50 of
/Moluidine was 656 mg/kg in the rat and 794 mg/kg in the mouse (IBT, 1973). The LD50 for
topical application was 890 mg/kg in the rabbit (IBT, 1973). A 1-hour exposure to 640 mg/kg of
/Moluidine in air failed to cause mortality in rats but was an ocular and upper respiratory irritant.
It is also a dermal sensitizer in guinea pigs (IBT, 1973).
Metabolism/Toxicokinetic Studies
Cheever et al. (1980) administered a single oral dose of /Moluidine (500 mg/kg) to male
S-D rats and collected the urine for 24 hours. Other animals were treated with m- or o-toluidine,
but these results are not relevant to this report. Metabolites were isolated and identified using
gas-liquid chromatography and mass spectrometry. Only 2.5% of the administered parent
compound was found in the urine. Metabolism proceeded primarily through ring hydroxylation
with subsequent conjugation. The major urinary metabolite was 2-amino-5-methylphenol. No
other metabolites were identified, and the toxicodynamics and toxicokinetics of /Moluidine were
not determined in this study.
Mechanistic/Mode of Action Studies
Gnojkowski et al. (1984) administered 76-mg/kg-day /Moluidine in sunflower oil by
intraperitoneal injection for 3 consecutive days to male Wistar rats. Other groups were treated
with m- or o-toluidine, but these results are not relevant to this report. On the fourth day, the rats
were euthanized, and their livers, kidneys, and lungs were excised. Microsomes were prepared
from the tissue samples. The activities of microsomal aryl hydrocarbon hydroxylase (AHH),
aminopyrine demethylase, NADPH-cytochrome c reductase, epoxide hydrolase, cytosolic
glutathione S-transferase, as well as the concentration of cytochrome P450 and cytochrome bs,
were determined in the samples. Differences (p < 0.05) between the treated groups and controls
were as follows: (1) cytochrome P450 decreased by 17%; (2) AHH decreased by 37%;
(3) aminopyrine demethylase decreased by 25%; (4) epoxide hydrolase increased by 172%; and
(5) glutathione S-transferase increased by 53%.
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DERIVATION OF PROVISIONAL VALUES
Table 4 presents a summary of noncancer reference values. Table 5 presents a summary of cancer reference values.
Table 4. Summary of Noncancer Reference Values for />-Toluidine (CASRN 106-49-0)
Toxicity Type (Units)
Species/
Sex
Critical Effect
Reference
Value
POD Method
POD
UFC
Principal Study
Screening Subchronic
p-RfD
(mg/kg-day)
Rat/M
Increased methemoglobin
content in blood
4 x l(T3
LOAEL
40
10,000
Jodynis-Liebert
and Bennasir
(2005)
Screening Chronic
p-RfD
(mg/kg-day)
Rat/F
Increased methemoglobin
content in blood
4 x l(T3
LOAEL
40
10,000
Malik-Brys and
Senczuk
(1995a,b,c)
Subchronic p-RfC
(mg/m3)
None
Chronic p-RfC
(mg/m3)
None
Table 5. Summary of Cancer Reference Values for />-Toluidine (CASRN 106-49-0)
Toxicity Type
Species/Sex
Tumor Type
Cancer Value
Principal Study
p-OSF
Mouse/M
Hepatica
3 x 10~2 (mg/kg-day) 1
Weisburger et al. (1978b)
p-IUR
None
aTumor type was not specified.
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DERIVATION OF ORAL REFERENCE DOSES
Derivation of Subchronic Provisional RfD (Subchronic p-RfD)
No subchronic p-RfD can be derived because the total composite UF for the derivation is
greater than 3000. However, Appendix A of this document contains a screening value that may
be useful in certain instances. Please see the attached appendix for details.
Derivation of Chronic Provisional RfD (Chronic p-RfD)
No chronic p-RfD can be derived because the total composite UF for the derivation is
greater than 3000. However, Appendix A of this document contains a screening value that may
be useful in certain instances. Please see the attached appendix for details.
DERIVATION OF INHALATION REFERENCE CONCENTRATIONS
No published studies investigating the effects of subchronic or chronic inhalation
exposure to /Moluidine in humans or animals were identified that were acceptable for use in risk
assessment.
CANCER WEIGHT-OF-EVIDENCE DESCRIPTOR
Table 6 identifies the cancer weight-of-evidence (WOE) descriptor for /Moluidine. There
were no studies available investigating the ability of /Moluidine to be carcinogenic in humans.
Weisburger et al. (1978b) found that liver tumors (type not reported) resulted when /Moluidine
was administered in the diet at doses of 17 and 35 mg/kg-day to male and female CD-I mice for
up to 18 months (followed by up to 3 months without treatment). Incidence of liver tumors was
statistically significantly increased in male mice when compared to both the concurrent and
pooled controls, and in female mice when compared to pooled controls only (see Table B.2).
Because the incidence of liver tumors in female mice was not statistically significant compared
to concurrent controls, the biological relevance of these tumors in female mice in this study may
be questionable. An increased incidence of liver tumors was not observed in male
Sprague-Dawley rats (the only sex tested) treated at 20 or 40 mg/kg-day for 18 months, followed
by up to 6 months without treatment (Weisburger et al., 1978a). No information was provided
regarding age of tumor onset. As the tumor types were not identified, it is unknown if there was
an increased incidence in malignant neoplasms. No other report could be located that provided
in vivo long-term carcinogenicity data for /Moluidine. p-Toluidine is an oncogen in a single
animal species (mouse) without any further results that demonstrate oncogenic potential due to
long-term exposure in vivo. As quoted in the EPA (2005) Guidelines for Carcinogen Risk
Assessment, one of the examples for a chemical to be considered "Likely to be carcinogenic to
humans " is: " ...an agent that has tested positive in animal experiments in more than one
species, sex, strain, site, or exposure route, with or without evidence of carcinogenicity in
humans. " Thus, the WOE from the Weisburger et al. (1978a,b) rodent studies indicates that
/Moluidine does not meet an examples to be considered as "Likely to be carcinogenic to
humans. " However, the available data are sufficient for /Moluidine to be considered to have
"Suggestive evidence of carcinogenic potential. "
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Table 6. Cancer WOE Descriptor for />-Toluidine (CASRN 106-49-0)
Possible WOE
Descriptor
Designation
Route of Entry
(Oral, Inhalation,
or Both)
Comments
"Carcinogenic to
Humans "
N/A
N/A
No human studies are available.
"Likely to be
Carcinogenic to
Humans "
N/A
N/A
As described above, /Moluidine does not
meet an example to be considered "likely to
be Carcinogenic to Humans. " (U.S. EPA,
2005)
"Suggestive
Evidence of
Carcinogenic
Potential"
Selected
Oral
As described above, the rodent data
(Weisburger et al., 1978a,b) indicate
suggestive evidence of carcinogenic
potential.
"Inadequate
Information to
Assess Carcinogenic
Potential"
N/A
N/A
There is evidence that /Moluidine is
carcinogenic in mice.
"Not likely to be
Carcinogenic to
Humans "
N/A
N/A
There is evidence that /Moluidine is
carcinogenic in mice.
MODE-OF-ACTION DISCUSSION
The Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005) define mode of action
".. .as a sequence of key events and processes, starting with the 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 a given chemical include
".. .mutagenicity, mitogenesis, inhibition of cell death, cytotoxicity with reparative cell
proliferation, and immune suppression" (p. 1-10).
There are discordant data on the potential mode of action for /Moluidine is unclear.
/>Toluidine was not mutagenic in S. typhimurium strains TA1535, TA1537, TA1538, TA98, or
TA100 or G46, in E. coli strains WP2, WP2 uvrA, C3076, or D3052, either in the presence or
absence of a rat liver activation (S9) system. Brock et al. (1990) demonstrated DNA-binding
following gavage treatment of Crl:CDBL rats; however, Weisburger et al. (1978a), a screening-
level study, demonstrated the absence of an increase in tumors in Crl:CDBL rats following
administration of 20- or 40-mg/kg-day /Moluidine in the diet for up to 18 months. Mayer (1977)
suggested that A'-hydroxylation of /Moluidine in vivo may result in bioactivation to a
carcinogenic product as evidenced by an induction in reciprocal mitotic recombination in
S. cerevisiae. However, the relative amount of /Moluidine that may undergo A'-hydroxylation
in vivo is unclear. The only other positive indicator of genotoxicity was a report indicating that a
35-mg/kg intraperitoneal injection of /Moluidine induced an increase in single-strand hepatic and
renal DNA breaks in male Swiss CD-I mice (ACGIH, 2001). Thus, the mode of carcinogenic
action for /Moluidine is unclear.
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DERIVATION OF PROVISIONAL CANCER POTENCY VALUES
Derivation of Provisional Oral Slope Factor (p-OSF)
The mouse study by Weisburger et al. (1978b) is selected as the principal study for
derivation of the p-OSF. The critical endpoint is hepatic tumors (type not specified) in CD-I
HaM/ICR mice. This study is generally well conducted, and the data from this study are able to
support a quantitative cancer dose-response assessment. This study is a peer-reviewed technical
report from the National Cancer Institute. It is unclear if this study was conducted according to
GLP standards, but it has an acceptable study design and performance with numbers of animals,
examination of potential toxicity endpoints, and presentation of information. This study is the
only available, acceptable study with a positive tumor response following /Moluidine oral
exposure.
The oral data are sufficient to derive a quantitative estimate of cancer risk using
benchmark dose (BMD) modeling. The dose-response data for liver tumors in male and female
mice (see Table B.2) can be used to derive a p-OSF for/>-toluidine. Statistical significance tests
were conducted by the study authors (Weisburger et al., 1978b) indicating that liver tumors in
male mice were statistically significant compared to pooled controls at the lowest dose tested,
and a statistically significant increase in tumor incidence compared to both pooled and
concurrent controls was observed at the highest dose. In female mice, incidence of liver tumors
was only statistically significant compared to pooled controls at the highest dose. Statistical
analyses performed in the principal study were done by Fisher's Exact Test.
Dosimetric adjustments were made for oral dietary administration of /Moluidine in
adjusting doses for oral cancer analysis (p-OSF). A sample calculation for the lowest dose tested
is shown below. Because the food concentration is a time-weighted average, it is not necessary
to include a duration adjustment in the human equivalent dose calculation.
Time-weighted
Food Concentration = ([(Nominal Dose x Months Dosed) + (Lower Dose x
Months Dosed)] ^ Total Months)
= ([(1000 mg/kg x 6 months) + (500 mg/kg x 12 months)]
21 months total)
= 571 mg/kg
DOSEred	= Time-weighted Food Concentration x Food Consumption per
Day x (l -h Body Weight) x (Body Weight Animal ^
Body Weight Human)0 25
= 571 mg/kg x 0.0055 kg/day x (1 - 0.030225 kg) x
(0.030225 kg -h 70 kg)0'25
= 15.0 mg/kg-day
Table B.2 presents BMD input data for incidence of liver tumors in mice exposed to
/Moluidine in feed for 18 months. The curve and BMD output text are provided in Appendix C.
Summary results for the BMDL modeling are presented in Table 7. The incidence of liver
tumors in male mice was considered the most sensitive tumor response because the modeled data
produced a slightly lower BMDio and BMDLio of 5.3 and 3.0 mg/kg-day, respectively,
compared to those from female mice.
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Table 7. Goodness-of-Fit Statistics, BMDiohed, and BMDLiohed Values for a Dichotomous
Model for Liver Tumors in CD-I Mice Treated with/>-Toluidine in the Diet for 18 Months3
Multistage Cancer Model
Goodness-of-fit
/?-Valueb
AIC
BMDiohed
(mg/kg-day)
BMDLiohed
(mg/kg-day)
Multistage Cancer
Male
0.426
69.31
5.3
3.0
Multistage Cancer
Female
0.999
31.05
16
8.3
"Wcisburgcr etal. (1978b).
bValues >0.1 meet conventional goodness-of-fit criteria.
p-OSF  BMR : BMDLiohed
= 0.1^-3.0 mg/kg-day
= 3 x 10~2 (mg/kg-day)-1
Derivation of Provisional Inhalation Unit Risk (p-IUR)
No suitable human or animal studies examining the carcinogenicity of /Moluidine
following inhalation exposure have been located. Therefore, derivation of a p-IUR is precluded.
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APPENDIX A. PROVISIONAL SCREENING VALUES
For reasons noted in the main PPRTV document, it is inappropriate to derive provisional
toxicity values for /Moluidine. 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 Superfund Health Risk
Technical Support Center 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 PPRTV 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
Superfund Health Risk Technical Support Center.
DERIVATION OF SCREENING PROVISIONAL ORAL REFERENCE DOSES
Derivation of Screening Subchronic Provisional RfD (Screening Subchronic p-RfD)
Jodynis-Liebert and Bennasir (2005) is selected as the principal study for derivation
of the screening subchronic p-RfD. The study by Jodynis-Liebert and Bennasir (2005) was not
stated to comply with GLP standards, and only a few selected parameters were evaluated.
However, pertinent data were reported to allow for the derivation of a screening subchronic
p-RfD, and this study was presented in a peer-reviewed journal. The critical endpoint is
increased methemoglobin content in blood, a clinical sign of /Moluidine exposure in humans
(ACGIH, 2001). The study by Jodynis-Liebert and Bennasir (2005) is detailed in the "Review of
Potentially Relevant Data" section.
Increases in methemoglobin content were statistically significant (p < 0.01) at all dose
groups for both exposure durations (i.e., 1 or 3 months) and both diet types (i.e., 4 or 14% fat).
For example, there was a 208% increase in methemoglobin blood content compared to controls
at 40 mg/kg-day in rats that received the 4% fat dietary treatment. There was also a statistical
significant increase in hepatic lipid peroxidation, a marker of oxidative stress. However, no
other indicators of liver pathology were assessed. Thus, it is impracticable to link this marker of
oxidative stress (i.e., liver peroxidation) to a toxicological outcome in the liver; therefore, hepatic
lipid peroxidation data are not considered relevant POD candidates and are not modeled by
Benchmark Dose Software (BMDS). Because increased methemoglobin content in blood was
the only potential critical effect observed in this study, it was the only endpoint modeled.
Specifically, all of the common continuous models (i.e., Linear, Polynomial, Power, and Hill)
available in the EPA's BMDS, version 2.1.2 were fit to the data. In general, model fit was
assessed by a %2 goodness-of-fit test (i.e., models withp < 0.1 failed to meet the goodness-of-fit
criterion) and the Akaike Information Criterion (AIC) value (i.e., a measure of the deviance of
the model fit that allows for comparison across models for a particular endpoint). BMD input for
the methemoglobin data are presented in Table B. 1. The modeling of the increased
methemoglobin data failed to provide an adequate fit as assessed by the %2 goodness-of-fit test.
Therefore, the LOAEL of 40 mg/kg-day based on increased methemoglobin content in male
rats (Jodynis-Liebert and Bennasir, 2005) was chosen as the POD to derive a screening
subchronic p-RfD.
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Adjusted for daily exposure:
The following dosimetric adjustments were made for each dose in the principal study for
dietary treatment.
DOSEadJ  DOSEj0dynis-Liebert and Bennasir, 2005 * [conversion tO daily dose]
= 40 mg/kg-day x (days of week dosed ^ 7 days in week)
= 40 mg/kg-day x 7 ^ 7
= 40 mg/kg-day
After considering all treatment-related endpoints, the screening subchronic p-RfD for
/Moluidine, based on the LOAEL of 40 mg/kg-day for increased methemoglobin levels in male
rats (Jodynis-Liebert and Bennasir, 2005), is derived as follows:
Screening Subchronic p-RfD = LOAELadj ^ UFC
= 40 mg/kg-day ^ 10,000
= 4 x 10~3 mg/kg-day
Table A.l summarizes the uncertainty factors for the screening subchronic p-RfD for
/Moluidine.
Table A.l. Uncertainty Factors for Screening Subchronic p-RfD of/>-Toluidinea
UF
Value
Justification
UFh
10
A UFh of 10 is applied for intraspecies differences to account for potentially
susceptible individuals in the absence of information on the variability of response
in humans.
ufa
10
A UFa of 10 is applied for interspecies extrapolation to account for potential
toxicokinetic and toxicodynamic differences between rats and humans. There are
no data to determine whether humans are more or less sensitive than rats to
increased methemoglobin content due to /Moluidine.
ufd
10
A UFd of 10 is applied because there are no acceptable two-generation reproduction
studies or developmental studies.
ufl
10
A UFl of 10 is applied because the POD was developed using a LOAEL.
UFS
1
A UFS of 1 is applied because a subchronic-duration study was utilized as the
principal study.
UFC
10,000

aJodynis-Liebert and Bennasir (2005).
Derivation of Screening Chronic Provisional RfD (Screening Chronic p-RfD)
Malik-Brys and Senczuk (1995a,b,c) is selected as the principal study for derivation
of the screening chronic p-RfD. The study by Malik-Brys and Senczuk (1995a,b,c) is the only
acceptable study observing the toxicological effects due to chronic exposure of /Moluidine. It
was not stated if this study complies with GLP standards, and only a few selected parameters
were evaluated. However, pertinent data were reported to allow for the derivation of a screening
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chronic p-RfD, and this study was presented in a peer-reviewed journal. The critical endpoint is
increased methemoglobin content in blood, a clinical sign of /Moluidine exposure in humans
(ACGIH, 2001). Malik-Brys and Senczuk (1995a,b,c) is detailed in the "Review of Potentially
Relevant Data" section.
Although no quantitative data were presented besides a bar graph, increases in
methemoglobin content were reported by the study authors to be statistically significant at all
dose groups for both diet types (8 or 24% protein) following 6 months exposure to dietary
administration of /Moluidine. Because no quantitative data were available, it is unclear what the
percent difference in methemoglobin levels was at the various dose groups. Other changes
observed included a decrease in the number of thrombocytes, erythrocytes, and leukocytes, as
well as an increase in the number of reticulocytes in animals exposed to the effect of toluidines;
however, the toxicological significance of these effects is unknown. Because increased
methemoglobin content in blood was the only critical effect observed in this study, it was the
only endpoint considered for derivation of a screening chronic p-RfD. As mentioned previously,
the absence of quantitative means and standard deviations prevents these data from being
modeled. Therefore, the LOAEL of 40 mg/kg-day based on increased methemoglobin
content in female rats (Malik-Brys and Senczuk (1995a,b,c) was chosen as the POD to
derive a screening chronic p-RfD.
Adjusted for daily exposure:
The following dosimetric adjustments were made for each dose in the principal study for
dietary treatment.
DOSEadj  DOSE\iaiik-iirys and Senczuk (i995a.b.c) x [conversion to daily dose]
= 40 mg/kg-day x (days of week dosed ^ 7 days in week)
= 40 mg/kg-day x 7 ^ 7
= 40 mg/kg-day
After considering all treatment-related endpoints, the screening chronic p-RfD for
/Moluidine, based on the LOAEL of 40 mg/kg-day for increased methemoglobin levels in female
rats (Malik-Brys and Senczuk, 1995a,b,c), is derived as follows:
Screening Chronic p-RfD = LOAELadj UFc
= 40 mg/kg-day ^ 10,000
= 4 x 10"3 mg/kg-day
Table A.2 summarizes the uncertainty factors that would be required to derive a
screening chronic p-RfD for /Moluidine.
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Table A.2. Uncertainty Factors for the Screening Chronic p-RfD of/>-Toluidinea
UF
Value
Justification
UFh
10
A UFh of 10 is applied for intraspecies differences to account for potentially
susceptible individuals in the absence of information on the variability of response
in humans.
UFa
10
A UFa of 10 is applied for interspecies extrapolation to account for potential
toxicokinetic and toxicodynamic differences between rats and humans. There are no
data to determine whether humans are more or less sensitive than rats to increased
methemoglobin content due to /Moluidinc.
ufd
10
A UFd of 10 is applied because there are no acceptable two-generation reproduction
studies or developmental studies.
ufl
10
A UFl of 10 is applied because the POD was developed using a LOAEL.
UFS
1
A UFS of 1 is applied because a chronic-duration study was utilized as the principal
study.
UFC
10,000

aMalik-Brys and Sericzuk (1995a,b,c).
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APPENDIX B. DATA TABLES
Table B.l. Mean  SD Methemoglobin Content (%) in the Blood of Rats Receiving


/J-Toluidine in the Diet3


Dose (mg/kg-day)
Month
0
40
80
160
4% Dietary fat
1
1.2 0.2
3.7  0.6b (+208)
4.3  0.5b (+258)
7.6  0.9b (+533)
3
1.4 0.2
6.6  2.30b (+371)
6.5  0.9b (+364)
13.2  2.4b (+843)
14% Dietary fat
1
1.5 0.2
3.6  0.5b (+140)
3.2  0.4b (+113)
6.1 0.6b (+307)
3
1.5  0.1
4.2  1.7b (+180)
4.1 0.5b (+173)
7.6  2.0b (+407)
aJodynis-Liebert and Bennasir (2005); percent difference from control, calculated from the cited data, is listed in
parentheses.
bDifference significant from control, p < 0.01 determined by Newman-Keuls Test.
Table B.2. Neoplastic Liver Lesions (# Affected/Total Surviving) in Mice Receiving

P-
Toluidine in the Diet for 18 Months3


DoseHED (mg/kg-day)
Sex
0
15
30
Pooled Controls
Males
3/18
8/17b
9/18b'c
7/99
Females
0/20
2/21
3/17b
1/102
aWeisburger etal. (1978).
bDifference significant from incidence in pooled control, p < 0.025 determined by Fisher's Exact Test as determined
by the study authors.
Difference significant from incidence in concurrent control, p < 0.05 determined by Fisher's Exact Test as
determined by the study authors.
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APPENDIX C. BENCHMARK DOSE (BMD) CALCULATIONS AND BMD MODELS
BMD CALCULATIONS FOR THE RFD
Modeling Procedure for Continuous Data
The BMD modeling of continuous data was conducted with EPA's benchmark dose
software (BMDS) (version 2.1.2 beta). For these data (i.e., increased methemoglobin content in
blood), all continuous models available within the software were fit using a benchmark response
(BMR) of one standard deviation. An adequate fit was judged based on the %2 goodness-of-fit
p-value (p> 0.1), the magnitude of the scaled residuals in the vicinity of the BMR, and the visual
inspection of the model fit. In addition to these three criteria forjudging adequacy of model fit, a
determination was made as to whether the variance across dose groups was homogeneous. If a
homogeneous variance model was deemed appropriate based on the statistical test provided in
BMDS (i.e., Test 2), the final BMD results were estimated from a homogeneous variance model.
If the test for homogeneity of variance was rejected (p < 0.1), the model was run again while
modeling the variance as a power function of the mean to account for this nonhomogeneous
variance. If this nonhomogeneous variance model did not adequately fit the data (i.e., Test 3;
p-v alue <0.1), the data set was considered unsuitable for BMD modeling.
Using data for increased methemoglobin content in male mice, modeling was performed
without constant variance, as initial analyses with constant variance models revealed poor model
fit. Data outputs from increased methemoglobin content in blood were evaluated, and the
outputs from these data were deemed invalid based on inadequate fit (goodness-of-fit/>value
<0.1) and are, therefore, not presented.
BMD CALCULATIONS FOR THE ORAL SLOPE FACTOR
Model-Fitting Procedure for Cancer Incidence Data
The model-fitting procedure for dichotomous cancer incidence data is as follows. The
multistage-cancer model in the EPA BMDS 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:
goodness-of-fit p-v alue (p > 0.1), visual inspection of the dose-response curve, and scaled
residual at the data point (except the control) closest to the predefined BMR. Among all the
models providing adequate fit to the data, the lowest bound of the BMD (BMDL) is selected as
the point of departure when the difference between the BMDLs estimated from these models is
more than 3-fold (unless it appears to be an outlier); otherwise, the BMDL from the model with
the lowest (Akaike Information Criterion) AIC is chosen. In accordance with EPA (2012)
guidance, BMDs and BMDLs associated with an extra risk of 10% are calculated.
Model-Fitting Results for Liver Tumors in HaM/ICR Derived CD-I Mice
(Weisburger et al., 1978)
Table B.2 shows the dose-response data on liver tumors in HaM/ICR derived CD-I mice
administered /Moluidine in the diet for 18 months (Weisburger et al., 1978). Modeling was
performed according to the procedure outlined above using BMDS version 2.1.2 with parameter
restrictions for mice based on the duration-adjusted HEDs shown in Table 2. Model predictions
are shown in Table 7. For both male and female mice, the multistage-cancer model provided an
adequate fit (goodness-of-fit p-v alue >0.1). The 1-degree polynomial model yielded BMDiohed
values of 5.3 and 16 mg/kg-day with an associated 95% lower confidence limit (BMDLiqhed) of
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3 and 8.3 mg/kg-day for male and female mice, respectively. The fit of the 1-degree
multistage-cancer model to the liver tumor incidence data for male and female mice is shown in
Table 7.
Multistage Cancer Model with 0.95 Confidence Level
0.8
Multistage Cancer
Linear extrapolation
BMD Lower Bound
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
BMDL
BMD
0
5
10
15
20
25
30
dose
16:42 06/15 2011
Figure C.l. Dichotomous-Multistage-Cancer BMD Model for Incidence of Liver Tumors
in Male Mice (Weisburger et al., 1978)
Text Output for Dichotomous-Multistage-Cancer BMD Model for Incidence of Liver
Tumors in Male Mice (Weisburger et al., 1978)
Multistage Cancer Model. (Version: 1.9; Date: 05/26/2010)
Input Data File: C:/Documents and Settings/JKaiser/Desktop/modeling
results/msc_ptol_ltumors_m_Mscl-BMR10.(d)
Gnuplot Plotting File: C:/Documents and Settings/JKaiser/Desktop/modeling
results/msc_ptol_ltumors_m_Mscl-BMR10.pit
Wed Jun 15 17:08:35 2011
BMDS Model Run
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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 = Response
Independent variable = Dose
Total number of observations = 3
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 = 250
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background =	0.219957
Beta(1) = 0.0170275
Asymptotic Correlation Matrix of Parameter Estimates
Background	Beta(l)
Background	1	-0.73
Beta (1)	-0.73	1
Parameter Estimates
95.0% Wald Confidence
Interval
Variable	Estimate	Std. Err.	Lower Conf. Limit Upper Conf.
Limit
Background	0.18347 6	*	*	*
Beta(1)	0.019892	*	*	*
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-32.3408
-32.6546
-35.1261
# Param's	Deviance	Test d.f.
3
2	0.627559	1
1	5.5705	2
P-value
0.4283
0. 06171
AIC:
69.3092
Goodness of Fit
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Scaled
Dose	Est._Prob. Expected Observed	Size	Residual
0.0000
0.1835
3.303
3.000
18
-0.184
15.0000
0.3941
6.700
8.000
17
0. 645
30.0000
0.5504
9.908
9.000
18
-0.430
Chi^2 = 0.64	d.f. = 1	P-value = 0.4255
Benchmark Dose Computation
Specified effect =	0.1
Risk Type =	Extra risk
Confidence level =	0.95
BMD =	5.29662
BMDL =	2.97513
BMDU =	19.8489
Taken together, (2.97513, 19.8489) is a 90	% two-sided confidence
interval for the BMD
Multistage Cancer Slope Factor =	0.033612
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Multistage Cancer Model with 0.95 Confidence Level
0.4
0.3
T3
0)
-t'
o
.2	0.2
-t'
o
5
LL
0.1
0
0	5	10	15	20	25	30
dose
17:10 06/15 2011
Figure C.2. Dichotomous-Multistage-Cancer BMD Model for Incidence of Liver Tumors
in Female Mice (Weisburger et al., 1978)
Text Output for Dichotomous-Multistage-Cancer BMD Model for Incidence of Liver
Tumors in Female Mice (Weisburger et al., 1978)
Multistage Cancer Model. (Version: 1.9; Date: 05/26/2010)
Input Data File: C:/Documents and Settings/JKaiser/Desktop/modeling
results/msc_ptol_ltumors_f_Mscl-BMR10.(d)
Gnuplot Plotting File: C:/Documents and Settings/JKaiser/Desktop/modeling
results/msc_ptol_ltumors_f_Mscl-BMR10.pit
Wed Jun 15 17:10:13 2011
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
Multistage Cancer
Linear extrapolation
BMD Lower Bound
BMDL
BMD
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Dependent variable = Response
Independent variable = Dose
Total number of observations = 3
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 = 250
Relative Function Convergence has been set to: le-008
Parameter Convergence has been set to: le-008
Default Initial Parameter Values
Background = 0.00100132
Beta(1) = 0.00647187
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)	0.00655066	*	*	*
* - Indicates that this value is not calculated.
Analysis of Deviance Table
Model
Full model
Fitted model
Reduced model
Log(likelihood)
-14.5263
-14.5269
-17.033
# Param's
3
1
1
Deviance Test d.f.
0. 00111128
5.01342
P-value
0.9994
0. 08154
AIC:	31.0538
Goodness of Fit
Scaled
Dose	Est._Prob. Expected Observed	Size	Residual
0.0000	0.0000	0.000	0.000	20	-0.000
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15.0000	0.0936	1.965	2.000	21
30.0000	0.1784	3.033	3.000	17
Chi^2 =0.00	d.f. = 2	P-value = 0.9994
Benchmark Dose Computation
Specified effect =	0.1
Risk Type =	Extra risk
Confidence level =	0.95
BMD =	16.084
BMDL =	8.34226
BMDU =	48.3837
Taken together, (8.34226, 48.3837) is a 90	% two-sided confidence
interval for the BMD
Multistage Cancer Slope Factor =	0.0119872
0. 026
-0.021
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APPENDIX D. REFERENCES
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Documentation of the threshold limit values and biological exposure indices. Cincinnati, OH:
ACGIH; pp. 1597-1599. 626899.
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values for chemical substances and physical agents and biological exposure indices. Cincinnati,
OH. As cited in HSDB (Hazardous Substances Data Bank). Available online at
http://toxnet.nlm.nih.gov/cgi-bin/sis/htmleen7HSDB. Accessed on 7/26/11.
ATSDR (Agency for Toxic Substances and Disease Registry). (2008) Toxicological profile
information sheet. U.S. Department of Health and Human Services, Public Health Service.
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Brock, WJ; Hundley, SG; Lieder, PH. (1990) Hepatic macromolecular binding and tissue
distribution of ortho- and para-toluidine in rats. Toxicol Lett 54(2-3):317-325. 597199.
CalEPA (California Environmental Protection Agency). (2008) All OEHHA acute, 8-hour and
chronic reference exposure levels (chRELs) as of December 18, 2008. Sacramento: Office of
Environmental Health Hazard Assessment. Available online at
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CalEPA (California Environmental Protection Agency). (2010) OEHHA/ARB approved
chronic reference exposure levels and target organs. Sacramento: Office of Environmental
Health Hazard Assessment. Available online at
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Cesarone, C.F.; Bolognesi, C.; Santi, L. (1982) Evaluation of damage to dna after in vitro
exposure to different classes of chemicals. Arch Toxicol Suppl. 5:355-359.
Cheever, KL; Richards, DE; Plotnick, HB. (1980) Metabolism of o-, m- and p-toluidine in the
adult male rat. Toxicol ApplPharmacol 56:361-369. 597201
HSDB (Hazardous Substances Data Bank). (2009) 4-Aminotoluene. Last review dated January
29, 2000. National Library of Medicine, National Toxicology Program, Bethesda, MD.
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Goldblatt, MW. (1955) Research in industrial health in the chemical industry. BrJlndMed
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IARC (International Agency for Research on Cancer). (2010) IARC Monographs on the
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IBT (Industrial Bio-Test Laboratories). (1973) Subacute feeding study (28 days) in male albino
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Malik-Brys, M; Senczuk, W. (1995a) Toxicodynamic properties of toluidines in chronic
poisoning. Part I. Experiments on animals maintained on protein-rich diet. Bromatol Chem
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Malik-Brys, M; Senczuk, W. (1995b) Toxicodynamic properties of toluidines in chronic
poisoning. Part II. Experiments on animals maintained on protein-rich diet. Bromatol Chem
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Malik-Brys, M; Senczuk, W. (1995c) Toxicodynamic properties of toluidines in chronic
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NIOSH (National Institute for Occupational Safety and Health). (2010) NIOSH pocket guide to
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OSHA (Occupational Safety and Health Administration). (2010) Air contaminants:
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Rosenkranz, HS; Poirier, LA. (1979) Evaluation of the mutagenicity and DNA-modifying
activity of carcinogens and noncarcinogens in microbial systems. J Natl Cancer Inst
62(4):873-892. 054576.
Scott, TS; Munn, A; Smagghe, G. (1983) Amines, aromalic. In: Parmeggiani, L, ed.
Encyclopaedia of occupational health and safety, 3rd Rev. ed., Vol. 1. Geneva: International
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Seiler, JP. (1977) Inhibition of testicular DNA synthesis by chemical mutagens and
carcinogens. Preliminary results in the validation of a novel short-term test. Mutat Res
46(4):30S-310.
Thompson, CZ; Hill, LE; Epp, JK; et al. (1983) The induction of bacterial mutation and
hepatocyte unscheduled DNA synthesis by monosubstituted anilines. Environ Mutagen
5(6):803811.
U.S. EPA (Environmental Protection Agency). (1985) Health and environmental effects Profile
(HEEP) for p-toluidine. Environmental Criteria and Assessment Office, Cincinnati, OH.
ECAO-CIN-P147. September.
U.S. EPA (Environmental Protection Agency). (1988) Recommendations for and
documentation of biological values for use in risk assessment Environmental Criteria and
Assessment Office, Office of Health and Environmental Assessment, Office of Research and
Development, U.S. Environmental Protection Agency, Cincinnati, OH; EPA/600/6-87/008.
Available online at http://cfpub.epa.eov/ncea/cfm/recordisplav.cfm?deid=34855.
U.S. EPA (Environmental Protection Agency). (1992) Dermal exposure assessment: principles
and applications. Office of Research and Development, Washingon, DC; EPA/600/8-91/01 IB.
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U.S. EPA (U.S. Environmental Protection Agency). (1994) Chemical assessments and related
activities (CARA). Office of Health and Environmental Assessment, Washington, DC;
EPA/600/R-94/904. Available online at
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U.S. EPA (Environmental Protection Agency). (1997) Exposure Factors Handbook (Final
Report). Office of Research and Development, National Center for Environmental Assessment,
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U.S. EPA (Environmental Protection Agency). (2012) Benchmark dose technical guidance.
Risk Assessment Forum, Washington, DC; EPA/100/R-12/001. Available online at
http://www.epa.gov/raf/publications/pdfs/benchmark dose guidance.pdf
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for p-toluidine. Prepared by the Superfund Health Risk Technical Center, National Center for
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U.S. EPA (Environmental Protection Agency). (2005) Guidelines for carcinogen risk
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