United States
*brmT"M\ Environmental Protection
^JrlLJ JTmAgency
EPA/690/R-13/001F
Final
5-2-2013
Provisional Peer-Reviewed Toxicity Values for
tert- Amyl Alcohol
(CASRN 75-85-4)
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 MANAGERS
J. Phillip Kaiser, PhD
National Center for Environmental Assessment, Cincinnati, OH
Senthilkumar Perumal-Kuppusamy, DVM, PhD
Oak Ridge Institute for Science and Education
National Center for Environmental Assessment, Cincinnati, OH
DRAFT DOCUMENT PREPARED BY
ICF International
9300 Lee Highway
Fairfax, VA 22031
PRIMARY INTERNAL REVIEWERS
Zheng (Jenny) Li, PhD, DABT
National Center for Environmental Assessment, Washington, DC
Paul G. Reinhart, PhD, DABT
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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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
ANIMAL STUDIES 7
Oral Exposures 7
Inhalation Exposures 7
OTHER DATA (SHORT-TERM TESTS, OTHER EXAMINATIONS) 13
Metabolic/Toxicokinetic Studies 13
DERIVATION 01 PROVISIONAL VALUES 14
DERIVATION OF ORAL REFERENCE DOSES 16
DERIVATION OF INHALATION REFERENCE CONCENTRATIONS 16
Derivation of Subchronic Provisional RfC (Subchronic p-RfC) 16
Derivation of Chronic Provisional RfC (Chronic p-RfC) 16
CANCER WEIGHT-OF-EVIDENCE (WOE) DESCRIPTOR 16
DERIVATION OF PROVISIONAL CANCER POTENCY VALUES 16
APPENDIX A. PROVISIONAL SCREENING VALUES 17
APPENDIX B. DATA TABLES 22
APPENDIX C. BMD OUTPUTS 36
APPENDIX D. REFERENCES 53
in
/f/V-Amyl alcohol
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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
NOAELhec
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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PEER-REVIEWED PROVISIONAL TOXICITY VALUES FOR
tert-AMYL ALCOHOL (CASRN 75-85-4)
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 (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
tert-Amyl alcohol [CASRN 75-85-4, also known as amylene hydrate or
2-methyl-2-butanol (NLM. 201 1 a)1. is used as a solvent for resins and gums and in the
production of plastics, and other chemicals such as arylpyruvic acids. It is also used as a frothing
and flotation agent (e.g., in ore-flotation processes) and in some pharmaceutical applications as a
sedative-hypnotic drug (NLM 201 lb), tert-Amyl alcohol has been shown to be a major
metabolite of /e/7-amyl methyl ether in rats, mice, rabbits, and humans (NLM. 2011b). The
molecular formula of tert-amyl alcohol is C5H12O (see Figure 1), and a table of physicochemical
properties for /m-amyl alcohol is provided below (see Table 1).
OH
Figure 1. tert-Amyl Alcohol Structure
Table 1. Physicochemical Properties of tert-Amyl Alcohol (CASRN 75-85-4)
Property (unit)
Value
Boiling point (°C)
102.4a'b
Melting point (°C)
-9. laor -8.803
Density (g/cm3)
0.8096b
Vapor pressure (mm Hg at 25°C)
16.8a or 16.7b
Log octanol-water partition coefficient (unitless)
0.89ab
Henry's law constant (atm-m3/mol)
1.38 x 10~5a
pH (unitless)
Neutralb
Solubility in water (g/100 mL at 25°C)
110a or 99. lb
Relative vapor density (air = 1)
ND
Molecular weight (g/mol)
88.15b
aNLM (2011a).
bNLM (2011b).
ND = not determined.
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Table 2 provides a summary of the available toxicity values for tert-amyl alcohol from
U.S. EPA and other agencies/organizations.
Table 2. Summary of Available Toxicity Values for tert-Amyl Alcohol (CASRN 75-85-4)
Source/Parameter"
Value
(Applicability)
Notes
Reference
Date Accessed
Cancer
IRIS
NV
NA
U.S. EPA (2012M
12-5-2011
HEAST
NV
NA
U.S. EPA (2003)
NA
IARC
NV
NA
IARC (2011)
12-5-2011
NTP
NV
NA
NTP (2011)
NA
Cal/EPA
NV
NA
Cal/EPA (2009)
NA
Noncancer
ACGIH
NV
NA
ACGIH (2011)
NA
ATSDR
NV
NA
ATSDR (20ID
12-5-2011
Cal/EPA
NV
NA
Cal/EPA (2012.
2008)
12-5-2011
NIOSH
NV
NA
NIOSH (2007)
NA
OSHA
NV
NA
OSHA (2006)
NA
IRIS
NV
NA
U.S. EPA (2012M
12-5-2011
Drinking water
NV
NA
U.S. EPA (2011)
NA
HEAST
NV
NA
U.S. EPA (2003)
NA
CARA HEEP
NV
NA
U.S. EPA (1994a)
NA
WHO
NV
NA
WHO (2012)
12-5-2011
aSources: Integrated Risk Information System (IRIS); Health Effects Assessment Summary Tables (HEAST);
International Agency for Research on Cancer (IARC); National Toxicology Program (NTP); California
Environmental Protection Agency (Cal/EPA); American Conference of Governmental Industrial Hygienists
(ACGIH); Agency for Toxic Substances and Disease Registry (ATSDR); National Institute for Occupational
Safety and Health (NIOSH); Occupational Safety and Health Administration (OSHA); Chemical Assessments and
Related Activities (CARA); Health and Environmental Effects Profile (HEEP); World Health Organization
(WHO).
NA = not applicable; NV = not available.
Literature searches were conducted on sources published from 1900 through
January 2013, for studies relevant to the derivation of provisional toxicity values for tert-amyl
alcohol, CAS No. 75-85-4. The following databases were searched by chemical name,
synonyms, or CAS No.: ACGIH, ANEUPL, ATSDR, BIOSIS, Cal/EPA, CCRIS, CD AT,
ChemlDplus, CIS, CRISP, DART, EMIC, EPIDEM, ETICBACK, FEDRIP, GENE-TOX,
HAPAB, HERO, HMTC, HSDB, IARC, INCHEM IPCS, IP A, ITER, IUCLID, LactMed,
NIOSH, NTIS, NTP, OSHA, OPP/RED, PESTAB, PPBIB, PPRTV, PubMed (toxicology
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subset), RISKLINE, RTECS, TOXLINE, TRI, U.S. EPA IRIS, U.S. EPAHEAST, U.S. EPA
HEEP, U.S. EPA OW, and U.S. EPA TSCATS/TSCATS2. The following databases were
searched for relevant health information values or exposure limits: ACGIH, ATSDR, Cal/EPA,
U.S. EPA IRIS, U.S. EPAHEAST, U.S. EPA HEEP, U.S. EPA OW, U.S. EPA
TSCATS/TSCATS2, NIOSH, NTP, OSHA, and RTECS.
REVIEW OF POTENTIALLY RELEVANT DATA
(CANCER AND NONCANCER)
Table 3 provides an overview of the relevant databases for fert-amyl alcohol and includes
all potentially relevant and repeated short-term-, subchronic-, and chronic-duration studies.
Principal studies are identified in bold. The phrase "statistically significant," used throughout
the document, indicates ap-value of <0.05. The phrase "biologically significant" as it pertains to
changes in absolute body weight or absolute and relative liver and kidney weights indicates a
>10% change from control values.
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Table 3. Summary of Potentially Relevant Data for tert-Amyl Alcohol (CASRN 75-85-4)
Category
Number of
Male/Female, Strain,
Species, Study Type,
Study Duration
Dosimetry"
Critical Effects
NO A EL'
BMDL/
BMCLa
LOAEL'
Reference
(Comments)
Notesb
Human
1. Oral (mg/kg-d)a
Acute0
ND
Short-termd
ND
Long-term6
ND
Chronicf
ND
2. Inhalation (mg/m3)a
Acute0
ND
Short-termd
ND
Long-term0
ND
Chronicf
ND
Animal
1. Oral (mg/kg-d)a
Subchronic
ND
Chronic
ND
Developmental
ND
Reproductive
ND
Carcinogenicity
ND
2. Inhalation (mg/m3)a
Subchronic
10/10, Fischer 344, rat,
inhalation, 6 hr/d, 5 d/wk,
85 d observed for males
and 86 d for females
0,7.58, 34.18, and
148.7 for males;
0, 7.61, 34.34, and
149.4 for females
Increased absolute and relative
liver weight in males
34.18
84.0 for
increased
absolute liver
weight in male
rats
148.7
Dow Chemical
Co (1992)
NPR
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Table 3. Summary of Potentially Relevant Data for tert-Amyl Alcohol (CASRN 75-85-4)
Category
Number of
Male/Female, Strain,
Species, Study Type,
Study Duration
Dosimetry"
Critical Effects
NOAEL3
BMDL/
BMCLa
LOAEL3
Reference
(Comments)
Notesb
Subchronic
10/10, CD-I, mouse,
inhalation, 6 hr/d, 5 d/wk,
86 d observed for males
and 87 d for females
0,31.8, 143.1, and
622.8 for males;
0,31.9, 143.8, and
625.9 for females
No significant treatment-related
effects
625.9
DUB
NDr
Dow Chemical
Co (1992)
NPR
4/0, Beagle, dog,
inhalation, 6 hr/d,
5 d/wk, 87 d observed
0,31.9,143.8, and
625.9
Increased absolute and relative
liver weight; cytoplasmic
inclusions in liver, increased
liver enzymes, and enlarged
liver
NDr
7.83 for
increased
absolute liver
weight
31.9
Dow Chemical
Co (1992)
NPR,
PS
Chronic
ND
Developmental
ND
Reproductive
ND
Carcinogenicity
ND
""Dosimetry: NOAEL, BMDL/BMCL, and LOAEL values are converted to a human equivalent concentration (HEC in mg/m3) for inhalation noncancer effects.
HECexresp = (ppm x MW ^ 24.45) x (hours per day exposed ^ 24) x (days exposed ^ total days observed) x blood-air partition coefficient (U.S. EPA. 1994b).
bNotes: IRIS = utilized by IRIS, date of last update; PS = principal study; PR = peer reviewed; NPR = not peer reviewed; NA = not applicable.
" Acute = exposure for <24 hr (U.S. EPA. 2002).
''Short-term = repeated exposure for >24 hr < 30 d (U.S. EPA. 2002).
"Long-term = repeated exposure for >30 d < 10% lifespan (based on 70-yr typical lifespan) (U.S. EPA. 2002).
'Chronic = repeated exposure for >10% lifespan (U.S. EPA. 2002).
DU = data unsuitable; DUB = data unamenable to BMDS; NA = not applicable; NV = not available; ND = no data; NDr = not determined; NI = not identified; NP = not
provided; NR = not reported; NR/Dr = not reported but determined from data; NS = not selected.
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HUMAN STUDIES
No studies were identified.
ANIMAL STUDIES
Oral Exposures
No studies were identified.
Inhalation Exposures
The effects of inhalation exposure to tert-amyl alcohol have not been evaluated in
short-term-duration, chronic-duration, developmental toxicity, or reproductive toxicity studies on
animals. However, a subchronic-duration study by Dow Chemical Co (1992) that investigated
the effects of tert-amyl alcohol in three species was identified. This study is considered
inadequate for p-RfC derivation because it is a nonpeer-reviewed and unpublished report.
However, this study is suitable for the derivation of screening provisional toxicity values (see
Appendix A).
Subchronic-duration Studies
The Dow Chemical Co (1992) conducted an unpublished, 87-day subchroni c-durati on
inhalation toxicity study on rats, mice, and dogs in May of 1977 and submitted a single study
report on all three species to the U.S. EPA under TSCA, Section 8(e) in April of 1992. The
study predates current Good Laboratory Practice (GLP) principles, and it is unknown whether
the study would be considered GLP compliant under current guidelines. For each species,
animals were placed in stainless steel chambers and exposed to target atmospheric concentrations
of 0-, 50-, 225-, or 1000-ppm tert-amyl alcohol (97.5% pure) for 6 hours per day, 5 days per
week. The total study duration varied from 85-87 days (59-61 exposures) depending on the
species and sex of the study animals; no explanation was given regarding why the study duration
and numbers of total exposures varied. The analytical concentrations averaged 50.5, 227.6, and
990.4 ppm for the low-, middle-, and high-exposure groups for all species tested, respectively.
A portion of each study within the Dow Chemical Co (1992) report examined the
clearance of tert-amyl alcohol from plasma in each species. The "Other Data" section of this
document further discusses the results of these clearance tests.
Rat Study
The Dow Chemical Co (1992) exposed groups of Fischer 344 rats (10 per sex per group)
to atmospheric tert-amyl alcohol. Male rats were exposed 59 times over 85 days, and females
were exposed 60 times over 86 days. Utilizing the analytical concentrations, the corresponding
HECs are 7.58, 34.18, and 148.7 mg/m3 for males and 7.61, 34.34, and 149.4 mg/m3 for females.
These HECs were calculated as specified in U.S. EPA (1994b) guidance, using a molecular
weight of 88.15 g/mole, adjusting for the exposure protocol (6 hours per day, 59 exposures per
85 days for male rats and 60 exposures per 86 days for female rats), and using a blood-air
partition coefficient of 0.24 based on blood-air partition coefficients of 392 in rat blood (Kaneko
et al.. 2000a) and 1620 in human blood (Vainiotalo et al.. 2007). The study authors recorded any
observations of behavioral changes and signs of toxicity after treatment. Animal tissues were
grossly and microscopically examined for lesions. All rats were weighed before the study, twice
per week during the first week of exposure, and once per week for the duration of the study.
Clinical chemistry, hematology, and urinalysis measurements were performed on all rats within
1 week of study termination. Clinical chemistry measurements included blood urea nitrogen
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(BUN), serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase
(SGOT), serum alkaline phosphatase (ALP), and glucose. Hematology measurements included
packed cell volume; red, white, and differential cell counts; and hemoglobin concentration.
Blood samples for clinical chemistry and hematology measurements were taken from the tail
vein of fasted rats. Urinalysis parameters included pH, specific gravity, glucose, ketones,
bilirubin, urobilinogen, and albumin. Urine excreted by the normal stress of handling the rats
was used in the urinalysis.
After the final exposure, all rats were subjected to a gross pathological examination at the
time of sacrifice. Rats were fasted overnight prior to sacrifice. At sacrifice, they were weighed,
anesthetized with methoxyflurane, and, after clamping the trachea, decapitated. The study
authors recorded the weights of the liver, kidney, heart, brain, and testes. The lungs and trachea
of the rats were removed as a unit and inflated with 10% formalin. The eyes of the rats were
examined immediately after decapitation in situ using the glass microscope slide technique under
fluorescent illumination. The eyes of five rats per sex per exposure level were fixed in Zenker's
solution. Representative samples of all major tissues and organs were taken from all rats and
fixed in 10% phosphate-buffered formalin. The following tissues and organs were harvested
from rats in this study: liver, heart, pancreas, spleen, brain, peripheral nerve, pituitary gland,
spinal cord, kidneys, adrenal glands, large intestine, small intestine, stomach, cecum, mesenteric
lymph node, thoracic lymph node, testes, epididymis, coagulating glands, seminal vesicles,
prostrate, urinary bladder, lungs, salivary glands, skeletal muscle, aorta, adipose tissue,
esophagus, thymus, parathyroid gland(s), thyroid gland, eyes, nasal turbinates, mesenteric
vasculature, integument, ovaries, oviducts, and uterus. These tissues were processed by standard
methods, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. Tissue
sections from five rats per sex from the control and high-exposure groups were extensively
examined with a light microscope. Except for the liver which was fully examined histologically
for all exposure groups, tissue sections from the remaining rats from the low- and mid-exposure
groups were microscopically examined only to the extent needed to identify the target organs of
toxicity and the NOAEL of this study.
Slight motor incoordination was observed in female rats in the high-exposure group
following the first exposure; however, no other signs of motor incoordination were observed at
any other exposure levels in males or females for the rest of the study. Excessive tearing was
observed starting at the 37th exposure in both female and male rats in the mid- and high-exposure
groups. Excessive tearing was more prevalent in high-exposure females, with the eyes of one
particular female were observed to be swollen shut on three separate occasions. No consistent
changes in mean body weight were observed among rats exposed to fert-amyl alcohol (see
Table B-5); however, the mean body weight of the low-exposure males was statistically
significantly decreased on Days 16 and 23; mean body weight of the high-exposure males was
statistically significantly decreased on Days 16 and 30 of the study. The clinical chemistry
results demonstrated that ALP was statistically significantly depressed in males and females in
the low-exposure group but not in rats exposed to higher concentrations (see Table B-2).
Statistically significant decreases in hematology values, including packed cell volume,
number of red blood cells, and hemoglobin concentration, were reported in the low-exposure
males relative to the control group (see Table B-3). White blood cell counts were statistically
significantly depressed in male rats in the mid- and high-exposure groups following the 54th
exposure, but when measured following the 57th exposure, the same pattern was not observed
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(see Table B-3). High-exposure female rats had statistically significantly depressed white blood
cell counts following the 55th exposure, but similar to the males, this pattern was not observed
following the 58th exposure. Female rats in the low-exposure group, however, showed a
statistically significant decrease in white blood cell counts following the 58th exposure (see
Table B-4). The study authors concluded that these changes in hematology values were not
toxicologically significant because they were not reproducible and did not exhibit an
exposure-response relationship.
The study authors observed a biologically and statistically significant increase in the
absolute and relative liver weights in male rats in the high-exposure group (13% and 14% higher
than the control, respectively; see Tables B-5 and B-6). A statistically significant increase in the
absolute liver weight was also observed in females in the mid-exposure group (9% higher than
the control; see Table B-5). However, the study authors attributed this increase to the higher
mean fasted body weights, and this change was not biologically significant (i.e., did not surpass
10%) of control). Additionally, the absolute heart weights of the males in the low-exposure group
and females in the mid-exposure group were >10% higher than the control; however, no
exposure-response relationships were evident, and the relative heart weights in these groups
were only minimally changed. The study authors also stated that a statistically significant
decrease in the relative heart weight (9% lower than the control) of the female rats in the
high-exposure group was spontaneous and unrelated to treatment. No effects were observed in
the urinalysis results of the exposed rats.
During the gross pathological examinations, slight mottling was observed in the kidneys
of 8/10 male rats and 0/10 female rats in the high-exposure group versus 1/10 male rats and
0/10 female rats in the control group. The study authors did not consider this effect treatment
related as it was not supported by other measures, such as kidney weight. Additionally, an
increase (not statistically significant) in gray pinpoint foci was observed in the lungs of male rats
exposed to tert-amyl alcohol, but the study authors concluded that this was not toxicologically
significant because higher incidences of these foci have been observed in historical control rats.
Based on the >10% biologically significant increase in absolute and relative liver weight
"3
in the high-exposure male rats, a lowest-observed-adverse-effect level (LOAEL) of 148.7 mg/m
is identified with a corresponding NOAEL of 34.18 mg/m3.
Mouse Study
The Dow Chemical Co (1992) exposed CD-I mice (10 per sex per group) to atmospheric
tert-amyl alcohol. Male mice were exposed 60 times over 86 days, and females were exposed
61 times over 87 days. Utilizing analytical concentrations, the corresponding HECs are 31.8,
143.1, and 622.8 mg/m3 for males and 31.9, 143.8, and 625.9 mg/m3 for females. These HECs
were calculated as specified in U.S. EPA (1994b) guidance, using a molecular weight of
88.15 g/mole, adjusting for the exposure protocol (6 hours per day, 60 exposures per 86 days for
male mice and 61 exposures per 87 days for female mice), and using a blood-air partition
coefficient of 1. All mice were observed for signs of toxicity and behavioral changes and were
weighed before the study, twice per week during the first week, and once per week for the
remainder of the study. Clinical chemistry measurements were taken on all mice at study
termination and included BUN, SGPT, SGOT, ALP, and glucose. Although not explicit in the
report, no hematology measurements or urinalysis appeared to be conducted.
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All mice were subjected to gross pathological examination after the final exposure
postmortem. The study authors reported that the mice were not fasted the day prior to the
sacrifice although the study authors provide fasted body weights in the results tables. Due to the
inconsistencies in the study report, the data reported are presented exactly as given. At sacrifice,
the mice were weighed, anesthetized with methoxyflurane, and, after clamping the trachea,
decapitated. The study authors recorded the weights of the liver, kidney, heart, brain, and testes.
The lungs and trachea of the mice were removed as a unit and inflated with 10% formalin. The
eyes of the mice were examined in situ using the glass microscope slide technique under
fluorescent illumination immediately after decapitation. The eyes of five mice per sex per
exposure level were fixed in Zenker's solution. Representative samples of all the major tissues
and organs were taken from all mice and fixed in 10% phosphate-buffered formalin. The
following tissues and organs were harvested from mice in this study: liver, gallbladder, heart,
pancreas, spleen, brain, peripheral nerve, pituitary gland, spinal cord, kidneys, adrenal glands,
large intestine, small intestine, stomach, cecum, mesenteric lymph node, thoracic lymph node,
testes, epididymides, coagulating glands, seminal vesicles, prostrate, urinary bladder, lungs,
salivary glands, skeletal muscle, aorta, adipose tissue, esophagus, thymus, parathyroid gland(s),
thyroid gland, eyes, nasal turbinates, mesenteric vasculature, integument, ovaries, oviducts,
uterus, skeletal muscle, anterior mediastinal blood vessels, trachea, subcutaneous lymph node,
cervical lymph node, cervix, and mammary gland. These tissues were processed by standard
methods, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. Tissue
"3
sections from five mice per sex from the control and 625.9 mg/m groups were extensively
examined with a light microscope. Tissue sections from the remaining mice from the low- and
mid-exposure groups were microscopically examined only to the extent required to identify the
target organs of toxicity and the NOAEL of this study.
Small, hairless patches were observed on the backs and necks of both male and female
mice exposed to fert-amyl alcohol. These patches were observed most frequently in
high-exposure males; however, the study authors concluded that these patches were not
exposure-related and were most likely attributable to fighting amongst the mice. Overall
changes in body-weight gains, which were derived from the fasted weights, were not statistically
significant (see Table B-7). Although the body weight gains observed in the female mice in the
high-exposure group were reduced compared to the control group, the study authors considered
this a questionable treatment-related effect due to the high variability in the weight gain data, as
evidenced by the relatively large standard deviation. BUN, SGPT, and SGOT were statistically
significantly depressed in male mice exposed to fert-amyl alcohol (see Table B-8), but the study
authors concluded that the decreases in these parameters were of unknown toxicological
significance. No hematology or urinalysis results were reported for these mice. The study
authors concluded that there were no treatment-related differences in the absolute organ weights
(see Table B-9) or relative organ weights (see Table B-10) of the males or females. However,
the study authors noted a biologically significant in the absolute liver weight (11% lower than
control) and a statistically and biologically significant decrease in relative liver weight
(15%) lower than control) of the male mice in the low-exposure group (see Tables B-9 and B-10).
The magnitude of these liver weight changes was not as great at the higher doses, therefore there
is no exposure-response relationship for these effects. The noted a statistically and biologically
significant decrease in the liver/body-weight ratio of the male mice in the low-exposure group
was attributed by the study authors to the small increase (not statistically or biologically
significant) in body weight of the group. Additionally, the female mice in the mid-exposure
group showed biologically significantly decreased absolute (21% lower than control) and relative
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kidney (11% lower than control) weights; however, the magnitude of these changes was not as
great at the high dose indicating that there is no exposure-response relationship for these effects
(see Tables B-9 and B-10). The study authors concluded that there were no treatment-related
gross or microscopic changes in the examined mouse tissue samples including the lungs;
however, the study authors observed an accentuation of the normal hepatocellular pattern as well
as focal aggregation of mononuclear cells in the liver of 2/5 male mice in the high-exposure
group (see Table B-l 1). The study authors determined that these findings represented normal
variation rather than toxic changes, as well as the other pathological changes that were observed
at similar frequencies in the other control and treatment groups.
"3
A NOAEL of 625.9 mg/m is identified based on the lack of observed systemic toxicity.
A corresponding LOAEL cannot be identified because the NOAEL was the highest
concentration tested.
Dog Study
The Dow Chemical Co (1992) exposed groups of four male beagle dogs to atmospheric
tert-amyl alcohol for 87 days (61 exposures). Utilizing analytical concentrations, the
corresponding HECs are 31.9, 143.8, and 625.9 mg/m . These HECs were calculated as
specified in U.S. EPA (1994b) guidance, using a molecular weight of 88.15 g/mole, adjusting for
the exposure protocol (6 hours per day, 61 exposures per 87 days), and using a blood-air partition
coefficient of 1. All dogs were observed for signs of toxicity after treatment and at regular
intervals, with a particular emphasis placed on examination of the nose and eyes. Ophthalmic
examinations (using a slit-lamp and ophthalmoscope) were conducted on all dogs before the start
of the study and during the last week of the study. All dogs were weighed before the study and
once per week during the study. Clinical chemistry, hematology, and urinalysis measurements
were taken on all dogs prior to the beginning of the study and during the last week of the study.
Blood samples for the clinical chemistry and hematological measurements were taken from the
dogs' jugular vein. Clinical chemistry measurements included BUN, SGPT, SGOT, ALP,
glucose, and y-glutamyl transpeptidase. Hematological measurements included packed cell
volume; red, white, and differential cell counts; and hemoglobin concentration. Urine was
extracted by catheterization analyzed for pH, specific gravity, glucose, ketones, bilirubin,
urobilinogen, albumin, and sediment.
After the final exposure, all of the dogs were subjected to a gross pathological
examination. The dogs were weighed, given an intravenous overdose of sodium pentobarbital,
and exsanguinated prior to sacrifice, but were not fasted. Weights of the liver, kidney, heart,
brain, and testes were recorded. The lungs and trachea of the dogs were removed as a unit and
inflated with 10% formalin. Representative samples of all major tissues and organs were taken
from all dogs and fixed in 10% phosphate-buffered formalin. The following tissues were
harvested from dogs in this study: liver, heart, pancreas, spleen, brain, spinal cord, pituitary,
peripheral nerve, adrenal gland, kidneys, small intestine, large intestine, stomach, gallbladder,
thymus, lymph nodes, epididymides, testes, prostrate, esophagus, lungs, trachea, aorta, tonsils,
parathyroid, thyroid, skeletal muscle, salivary gland, integument, eyes, tongue, nasal turbinates,
adipose tissue, urinary bladder, and mesenteric vasculature. These tissues were processed by
standard methods, embedded in paraffin, sectioned, and stained with hematoxylin and eosin.
"3
The tissues from all four dogs in the control and the 625.9 mg/m tert-amyl alcohol exposure
groups were extensively examined with a light microscope. Except for the liver which was fully
examined histologically for all exposure groups, tissues from the remaining animals from the
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low- and mid-exposure groups were microscopically examined only to the extent needed to
identify the target organs for toxicity and the NOAEL of this study. To determine glycogen
content, sections of the livers were stained with Periodic Acid-Schiff reagent (PAS), with and
without diastase digestion.
Visible, but reversible, motor impairments were observed in all dogs in the high-exposure
group. However, the dogs experienced these effects to different degrees. Blood samples
collected to determine the cause of these different degrees of motor impairment showed a 4-fold
difference in the concentration of tert-amyl alcohol. The highest concentrations were found in
the most impaired dogs. Excessive tearing was observed in one dog in the high-exposure group.
No significant differences were observed in the body-weight gains of dogs exposed to tert-amyl
alcohol and control dogs throughout the duration of this study (see Table B-12). The only
change in clinical chemistry parameters that the study authors considered toxicologically
significant was a statistically significant increase in ALP in the high-exposure group (see
Table B-13). Increased ALP is most commonly associated with bile duct obstruction, gall
bladder disease, and liver disease such as hepatitis; however, the study authors did not report an
increase in bilirubin. Additionally, blood glucose was statistically significantly elevated in the
low-exposure group, and SGPT was statistically significantly elevated in the high-exposure
group (see Table B-13). Hematology measurements demonstrated that the packed cell volume
and hemoglobin concentration were both statistically significantly elevated in the low- and
mid-exposure groups relative to the control group (see Table B-14); however, the study authors
concluded that these results were not treatment related because the levels were similar to
preexposure levels and because neither parameter was not statistically significantly elevated in
the high-exposure group. Urinalysis measurements indicated that specific gravity was
statistically significantly elevated only in the high-exposure group (see Table B-15). Statistically
significant increases in absolute (32% higher than the control) and relative liver weight
(37% higher than the control) were found in the high-exposure group (see Tables B-16 and
B-17). Also, biologically significant (greater than 10% compared to controls) increases in liver
weight (absolute and relative) were observed in all dose groups (except for relative liver weight
in the low-exposure group). Upon further review of the individual liver-weight data for beagles
in the low-exposure group, it appeared that the data for one animal may be an outlier. The value
in question is 541 g reported for absolute liver weight compared to other weights in the same
group of 361.08, 385.50, and 398.52 g. The study authors provided further reasoning (on
page 12 of principal study) to classify this value as an outlier: "The recorded liver weight for the
remaining animal was larger than that of any other animal in the study. This appears to be a
spurious value since this animal's liver was normal in size and appearance on gross
examination, and no changes were found in the other measured parameters which would
corroborate an effect of this magnitude on the liver." Based on this explanation provided by the
study authors, liver-weight data for this particular animal were removed from any further
analysis and mean values for absolute and relative liver weight were recalculated. The average
for absolute liver weight changed from 422.30 to 382.73 g, and relative liver weight changed
from 3.30 to 3.03 g. Based on the recalculated averages, relative liver weight was no longer
biologically significantly increased in beagles in the low-exposure group. Additionally, while
the absolute and relative kidney weights were not statistically significantly elevated, they were
14%) and 17% higher in the high-exposure group compared with the control group, respectively.
The low-exposure group also demonstrated a 15% lower absolute kidney weight compared with
the control, but the corresponding change in the relative kidney weight was only 2%. Slight
changes in either measure of kidney weight were observed in the mid-exposure group.
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All findings from the ophthalmic examination were normal, and no differences were
observed between the exposed and control dogs. On gross examination, livers were enlarged in
all dogs of the high-exposure group and in one dog of the mid-exposure group (see Table B-18).
Gross and microscopic lesions were observed in the lungs of most of the exposed and control
dogs, which were attributed to infection by the parasitic nematode Filaroides hirthi. Liver
cytoplasmic eosinophilic inclusion bodies were also noted in one dog from each of low-, mid-,
and high-exposure groups; none were reported in the control group (see Table B-18). Both the
size and number of these inclusions were greater in the mid- and high-exposure groups than the
low-exposure group, although this could not be confirmed by the data reported in the study.
Though of questionable toxicological significance, the study authors concluded that these liver
cytoplasmic inclusions should be considered exposure-related due to the apparent
exposure-response relationship, the statistically and biologically significantly increased absolute
and relative liver weights, and the clinical chemistry findings, all of which suggest that the liver
is a primary target organ for tert-amyl alcohol toxicity.
"3
A LOAEL of 31.9 mg/m (50 ppm) is identified based on a >10% biologically significant
increase in absolute liver weight. This is supported by findings of cytoplasmic eosinophilic
inclusions, enlarged livers, and exposure-dependent increased serum liver enzymes. Because the
low-exposure group is identified as the LOAEL, identification of a corresponding NOAEL is
precluded.
OTHER DATA (SHORT-TERM TESTS, OTHER EXAMINATIONS)
None of the following types of studies on the effects of tert-amyl alcohol were identified:
short-term studies; immunotoxicity, neurotoxicity, carcinogenicity, genotoxicity, or mutagenicity
studies; dermal studies or other routes of exposure; and mode-of-action/mechanistic studies.
Several studies were identified that discuss the metabolism and toxicokinetics of tert-amyl
alcohol and they are summarized below.
Metabolic/Toxicokinetic Studies
tert-Amy\ alcohol is the primary metabolite of tert-amyl methyl ether. Following
inhalation or gavage administration, tert-amyl methyl ether is readily metabolized to tert-amyl
alcohol by demethylation of the ether group. As the primary metabolite, the toxicokinetics of
tert-amyl alcohol have mainly been described as part of studies examining exposure to tert-amyl
methyl ether. The previously discussed study by Dow Chemical Co (1992) examined the
pharmacokinetics of tert-amyl alcohol after direct inhalation exposure in rats, mice, and dogs at
concentrations of 50, 225, or 1000 ppm for 6 hours per day, 5 days per week, for several months.
Although the study does not indicate the percentage of the inhaled dose that was absorbed, the
presence of tert-amyl alcohol in the plasma within 30 minutes of exposure indicates that the
compound is absorbed. In addition, blood-air partition coefficients of 392 in rat blood (Kaneko
et al.. 2000a) and 1620 in human blood (Vainiotalo et al.. 2007) indicate an affinity for blood and
that absorption is likely. There are no data on absorption following oral exposure. There are no
distribution studies on /c/V-amyl alcohol, but data by Kaneko et al. (2000b) indicate that
tert-amyl alcohol has an affinity for all tissues. Most of the available metabolism studies
exposed animals to tert-amyl methyl ether, but Arnberg et al. (1999) examined urinary
metabolites after oral exposure to either tert-amyl alcohol or tert-amyl methyl ether and found
the same metabolites (indicating that tert-amyl alcohol is the first step in the metabolism of
tert-amyl methyl ether). The major urinary metabolites recovered from rats exposed to tert-amyl
alcohol were tert-amyl alcohol glucuronide and 2-methyl-2,3-butanediol and its glucuronide; the
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minor metabolites included free tert-amyl alcohol, 2-hydroxy-2-methylbutyric acid, and
3-hydroxy-3-methylbutyric acid. Mannerine and Shoeman (1996) found that tert-amyl alcohol is
an active inducer of cytochrome P4503A, in addition to inducing P4502E and P4501A to some
extent, in mouse livers. The study authors suggested that tert-amyl alcohol may be metabolized
to an olefin by P450.
tert-.\my\ alcohol is rapidly cleared from the blood of exposed animals (Amberg et al..
2000). Dow Chemical Co (1992) found that the elimination of tert-amyl alcohol is slower in rats
(half-life of 47 minutes at 50 ppm) than in mice (half-life of 29 minutes at 1000 ppm), but faster
in both species compared to dogs (half-life of 69 minutes at 50 ppm); however, data do not
indicate any evidence of saturation at a concentration of 1000 ppm in mice, while rats and dogs
demonstrate saturation at 1000 ppm. All species demonstrated first-order clearance kinetics;
however, at 1000 ppm, rats and dogs are best described by first-order kinetics assuming either
Michaelis-Menten or saturation kinetics. The data indicate a low potential for accumulation in
the blood of dogs exposed to concentrations >1000 ppm because similar levels were measured
after 2, 3, or 4 months (Dow Chemical Co. 1992). Sumner et al. (2003c) also found that the
half-life of tert-amyl alcohol in blood is longer in rats (1-1.7 hours) than in mice
(0.2-0.8 hours). Furthermore, Sumner et al. (2003b) determined that the blood concentrations of
tert-amyl alcohol were 2- to 3-fold higher in mice compared to rats, either receiving 500- or
2500-ppm /t77-amyl methyl ether via inhalation (nose-only). After exposure to tert-amyl methyl
ether, fert-amyl alcohol is primarily found in expired air and urine (Sumner et al.. 2003a).
There is a single physiologically based pharmacokinetic (PBPK) model for fert-amyl
alcohol (Collins et al.. 1999); however, this model is not appropriate for use in dosimetric
conversions because the author concluded that it underpredicted the results. In the model,
tert-amyl alcohol has three compartments (i.e., lung, liver, and total body water) that are linked
to the metabolism of tert-amyl methyl ether in the liver. This model was compared with data
collected from male Fischer 344 rats after a 6-hour exposure to 100-, 500-, or 2500-ppm
tert-amyl methyl ether. The tert-amyl alcohol model underpredicted the results. Three
hypotheses were tested, and the one that fit the data best was the nonspecific binding of fert-amyl
alcohol. It should be noted that the partition coefficients used for tert-amyl alcohol were actually
those of tert-butyl alcohol because the physical and chemical properties are similar.
DERIVATION OF PROVISIONAL VALUES
Tables 4 and 5 present summaries of noncancer and cancer reference values, respectively.
IRIS data are indicated in the tables, if available.
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Table 4. Summary of Noncancer Reference Values for tert-Amyl Alcohol (CASRN 75-85-4)
Toxicity Type (units)
Species/Sex
Critical Effect
p-Reference
Value
POD Method
POD
UFC
Principal Study
Subchronic p-RfD
(mg/kg-d)
NDr
Chronic p-RfD
(mg/kg-d)
NDr
Screening subchronic p-RfC
(mg/m3)a
Dog/M
Increased absolute liver weight
3 x 1(T2
BMCLjqhec
7.83
300
Dow Chemical Co
(1992)
Screening chronic p-RfC
(mg/m3)a
Dog/M
Increased absolute liver weight
3 x 1(T3
BMCLjqhec
7.83
3000
Dow Chemical Co
(1992)
aA provisional screening value is provided in Appendix A to this document.
NDr = not determined.
Table 5. Summary of Cancer Values for tert-Amyl Alcohol (CASRN 75-85-4)
Toxicity Type
Species/Sex
Tumor Type
Cancer Value
Principal Study
p-OSF
NDr
p-IUR
NDr
NDr = not determined.
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DERIVATION OF ORAL REFERENCE DOSES
No studies were identified.
DERIVATION OF INHALATION REFERENCE CONCENTRATIONS
Derivation of Subchronic Provisional RfC (Subchronic p-RfC)
There are three sub chronic-duration exposures presented in one study on tert- amyl
alcohol in animals (see Table 3). The 12-week inhalation study performed by Dow Chemical Co
(1992) is the only available study on tert-amyl alcohol exposure. However, Dow Chemical Co
(1992) is considered inadequate for p-RfC derivation because it is not peer-reviewed and is an
unpublished report. This study is suitable, however, for the derivation of screening provisional
toxicity values. Appendix A provides details on the screening subchronic p-RfC.
Derivation of Chronic Provisional RfC (Chronic p-RfC)
There are no chronic-duration studies for tert-amyl alcohol for derivation of a chronic
p-RfC. However, the unpublished subchronic inhalation study by Dow Chemical Co (1992) is
suitable for derivation of a screening provisional chronic toxicity value. Appendix A provides
details on the screening chronic p-RfC.
CANCER WEIGHT-OF-EVIDENCE (WOE) DESCRIPTOR
Table 6 identifies the cancer weight-of-evidence (WOE) descriptor for tert-amyl alcohol.
Table 6. Cancer WOE Descriptor for tert-Amyl Alcohol
Possible WOE Descriptor
Designation
Route of Entry (Oral,
Inhalation, or Both)
Comments
"Carcinogenic to Humans "
NS
NA
No human cancer studies are available.
"Likely to Be Carcinogenic
to Humans "
NS
NA
No animal cancer data are available.
"Suggestive Evidence of
Carcinogenic Potential"
NS
NA
No animal cancer data are available.
"Inadequate Information
to Assess Carcinogenic
Potential"
Selected
Both
No adequate information is available to
assess the carcinogenic potential of
tert-amyl alcohol by inhalation or oral
routes of exposure.
"Not Likely to Be
Carcinogenic to Humans"
NS
NA
No evidence of carcinogenicity in humans
is available.
NA = not applicable; NS = not selected.
DERIVATION OF PROVISIONAL CANCER POTENCY VALUES
No studies were identified.
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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 tert-amyl alcohol. 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 REFERENCES DOSES
No studies were identified.
DERIVATION OF SCREENING PROVISIONAL INHALATION REFERENCE
CONCENTRATIONS
Derivation of Screening Subchronic Provisional RfC (Subchronic p-RfC)
The portion of the Pow Chemical Co (1992) study on dogs is selected as the
principal study for the derivation of the screening subchronic p-RfC. The critical effect is
increased mean absolute liver weight observed in male dogs. The 12-week inhalation study
performed by Dow Chemical Co (1992) is the only available subchronic-duration exposure
study, but it is considered inadequate for provisional p-RfC derivation because it is not
peer-reviewed and is an unpublished report. However, this study is otherwise well conducted
and suitable for the derivation of a screening provisional toxicity value. This study was
performed prior to the establishment of GLP principles although it appears to follow general
GLP principles. This study otherwise meets the standards of study design and performance in
terms of the number of study animals, examination of the potential toxicity endpoints, and
presentation of information. Study details are provided in the "Review of Potentially Relevant
Data" section.
Exposure concentrations from this study were adjusted for intermittent dosing [as per
guidance provided by U.S. EPA (2002)1. and human equivalent concentrations (HECs) were
"3
determined prior to modeling. The LOAELhec of 31.9 mg/m for dogs and 148.7 for male rats
was calculated by using U.S. EPA (1994b) methodology for an extrarespiratory effect as follows:
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Exposure concentration adjustment for continuous exposure:
For male dogs:
LOAELadj = LOAELppm. analytical x (MW 24.45) x (hours exposed ^ 24 hours)
x (days exposed ^ 87 days)
= 50.5 ppm x (88.15 g/mol 24.45) x (6 hours 24 hours) x
(61 days ^ 87 days)
= 182.8 mg/m3 x (6 hours ^ 24 hours) x (61 days ^ 87 days)
= 31.9 mg/m3
For male rats:
LOAELadj = LOAEL
ppm, analytical
(MW ^ 24.45) x (hours exposed ^ 24 hours)
x (days exposed -^85 days)
= 990.4 ppm x (88.15 g/mol 24.45) x (6 hours 24 hours) x
(59 days ^-85 days)
= 3570.7 x (6 hours ^ 24 hours) x (59 days ^ 85 days)
= 619.6 mg/m3
HEC conversion for extrarespiratory effects:
For male dogs:
LOAELhec = LOAELadj x (Hb/g)A ^ (Hb/g)H
= 31.9 mg/m x 1
= 31.9 mg/m3
For male rats:
LOAELhec - LOAELadj x (Hb/g)A ^ (Hb/g)H
= 619.6 mg/m3 x 0.24
= 148.7 mg/m3
where:
(Hb/g)A ^ (Hb/g)H = the ratio of the blood:gas (air) partition coefficient of the chemical
for the laboratory animal species to the human value. In the
absence of data for tert-amyl alcohol for beagles, the default value
of 1 was used, as specified in U.S. EPA (1994b) guidance. The
ratio of the blood:gas (air) partition coefficient for rats was 0.24
based on rat (Kaneko et al.. 2000a) and human data (Vainiotalo et
at.., 2007).
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The Dow Chemical Co (1992) study report includes data on three species: rats, mice, and
dogs. The experimental methods and endpoints were similar across species. The most sensitive
endpoints observed to be statistically and/or biologically significantly increased in the Dow
Chemical Co (1992) study were absolute and relative liver weights in male beagle dogs and rats
and alkaline phosphatase activity in male beagles; all of the common continuous models (i.e.,
Exponential, Linear, Polynomial, Power, and Hill models) available in the EPA's Benchmark
Dose Software (BMDS, version 2.1.2) were fit to these data if possible; see Appendix C for
modeling results and BMD methodology. Because liver-weight changes >10% are considered
biologically significant at that level, all models were run with a benchmark response (BMR) of
10% relative risk. For increased absolute liver weight in male beagles, BMD modeling resulted
3 3
in BMC iohec and BMCLiohec values of 33.5 mg/m and 7.83 mg/m , respectively. For increased
absolute liver weight in male rats, BMD modeling provided BMCiohec and BMCLiohec values
3 3
of 110 mg/m and 84.0 mg/m , respectively. For increased relative liver weight in male rats,
BMD analysis resulted in BMCiohec and BMCLiohec values of 102 mg/m3 and 86.6 mg/m3,
respectively. For increased ALP activity in male beagles, all models were run with a benchmark
response (BMR) of 1 standard deviation resulting in BMCisd and BMCLisd values of
3 3
87.4 mg/m and 57.8 mg/m , respectively. For increased relative liver weight in male beagles,
the BMD analysis resulted in significant lack of fit (Test 3,/> < 0. 10) for all continuous models
employing nonconstant variance (see Table C-2). Because these data were not amenable to
BMD modeling, a NOAEL/LOAEL approach was employed to identify a potential point of
departure (POD). For increased relative liver weight in male beagles, a biologically significant
increase was observed in the mid-dose group, identifying a LOAEL of 143.8 mg/m3 with a
"3
corresponding NOAEL of 31.9 mg/m .
Of the toxicological effects observed in male beagles and rats in the subchronic-duration
study by the Dow Chemical Co (1992). the most sensitive is increased absolute liver weight in
beagles with a BMCLiohec of 7.83 mg/m3. The selection of increased absolute liver weight in
beagles as the critical effect is supported by exposure-dependent increased liver enzymes
(statistically significant at 625.9 mg/m3), observations of enlarged livers (statistically significant
"3
at 625.9 mg/m ), and hepatic cytoplasmic eosinophilic inclusions (not statistically significant at
any dose but considered to be exposure-related by the study authors). The selection of the
"3
BMCLiohec of 7.83 mg/m for increased absolute liver weight in male beagles as the POD would
not only protect against this effect but also other liver effects (e.g., increased liver enzymes) that
occurred at higher concentrations in dogs. Based on the toxicity findings in the three tested
species, dogs are the most sensitive to the effects of fert-amyl alcohol. Therefore, the selection
"3
of the POD (BMCLiohec of 7.83 mg/m ) in dogs is also protective against effects observed in
rats and mice. Therefore, the BMCLiohec of 7.83 mg/m3 based on increased absolute liver
weight in male beagles (Dow Chemical C o. 1992) is chosen as the POD to derive a screening
subchronic p-RfC.
The screening subchronic p-RfC for tert-amyl alcohol is derived as follows:
Screening Subchronic p-RfC = BMCLiohec UFC
= 7.83 mg/m3 -300
= 3 x 10" mg/m3
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Table A-l summarizes the uncertainty factors (UFs) for the screening subchronic p-RfC
for tert-amyl alcohol. Confidence in the screening value is by definition, low.
Table A-l. UFs for Screening Subchronic p-RfC for tert-Amyl Alcohol
UF
Value
Justification
ufa
3
A UFa of 3 (10°5) is applied to account for uncertainty in characterizing the toxicodynamic
differences between dogs and humans following inhalation exposure to fer/-amyl alcohol. The
toxicokinetic uncertainty has been accounted for by calculation of a human equivalent
concentration (HEC) as described in the RfC methodology (U.S. EPA. 1994b).
ufd
10
A UFd of 10 is applied because there are no acceptable two-generation reproductive toxicity or
developmental toxicity studies via the inhalation route.
UFh
10
A UFh of 10 is applied for inter-individual variability to account for human-to-human variability
in susceptibility in the absence of quantitative information to assess the toxicokinetics and
toxicodynamics of fer/-amyl alcohol in humans.
ufl
1
A UFl of 1 is applied for LOAEL-to-NOAEL extrapolation because the POD is a BMCL.
UFS
1
A UFS of 1 is applied because a subchronic-duration study was selected as the principal study.
UFC
300
UFC = UFa x UFd x UFh x UFl x UFs
Derivation of Screening Chronic Provisional RfC (Chronic p-RfC)
Because no chronic-duration studies exist for fert-amyl alcohol, the dog portion of the
nonpeer-reviewed subchronic study by the Dow Chemical Co (1992) is also selected as the
principal study for derivation of the screening chronic p-RfC. For the same reasons listed above
in the screening subchronic p-RfC discussion, the study by Dow Chemical Co (1992) meets
standards of study design and performance. Details are provided in the "Review of Potentially
Relevant Data" section.
"3
The chronic p-RfC for /t7-/-amyl alcohol, based on a BMCLiohec of 7.83 mg/m for
increased absolute liver weight in male beagles, is derived as follows:
Screening Chronic p-RfC = BMCLiohec UF
= 7.83 mg/m3 -3000
= 3 x 10" mg/m3
Table A-2 summarizes the UFs for the screening chronic p-RfC for tert-amyl alcohol.
Confidence in the screening value is by definition, low.
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Table A-2. UFs for Screening Chronic p-RfC for tert-Amyl Alcohol
UF
Value
Justification
ufa
3
A UFa of 3 (10°5) is applied to account for uncertainty in characterizing the toxicodynamic
differences between dogs and humans following inhalation exposure to fer/-amyl alcohol. The
toxicokinetic uncertainty has been accounted for by calculation of a human equivalent
concentration (HEC) as described in the RfC methodology (U.S. EPA. 1994b).
ufd
10
A UFd of 10 is applied because there are no acceptable two-generation reproductive toxicity or
developmental toxicity studies via the inhalation route.
UFh
10
A UFh of 10 is applied for inter-individual variability to account for human-to-human variability
in susceptibility in the absence of quantitative information to assess the toxicokinetics and
toxicodynamics of fer/-amyl alcohol in humans.
ufl
1
A UFl of 1 is applied for LOAEL-to-NOAEL extrapolation because the POD is a BMCL.
UFS
10
A UFS of 10 is applied because a subchronic-duration study was selected as the principal study.
UFC
3000
UFC = UFa x UFd x UFh x UFl x UFs
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APPENDIX B. DATA TABLES
Table B-l. Body-Weight Gain in Male and Female Fischer 344 Rats Exposed to tert-Amyl
Alcohol by Inhalation for 12 Weeks"
Exposure Concentration in ppmb
Endpoint
0
50
225
1000
Males (59 exposures)"1
Number of animals
10
10
10
10
Body-weight gain (g)°
106.2 ±20.1
108.6 ±23.2
99.8 ± 17.7
104.0 ±23.2
Females (60 exposures)"1
Number of animals
10
10
10
10
Body-weight gain (g)°
36.5 ±9.8
40.4 ± 10.5
41.0 ±9.2
38.4 ± 14.2
aDow Chemical Co (19921.
bCorresponding HECs are 7.58, 34.18, and 148.7 mg/m3 for males and 7.61, 34.34, and 149.4 mg/m3 for females.
°Mean ± standard deviation; calculated from the mean body weights in the study report.
dThe legibility of the original study makes it difficult to decipher these values.
Table B-2. Selected Clinical Chemistry Parameters in Male and Female Fischer 344 Rats
Exposed to tert-Amyl Alcohol by Inhalation for 12 Weeks"
Exposure Concentration in ppmb
Endpoint
0
50
225
1000
Males (59 exposures)
Number of animals
10
10
10
10
Serum Alkaline Phosphatase (|iUnits/mL)c
78 ±4
68 ±5*
73 ±6
84 ± 10
Females (60 exposures)
Number of animals
10
10
10
10
Serum Alkaline Phosphatase (|iUnits/mL)c
66 ±7
57 ±5*
61 ±6
73 ±8
aDow Chemical Co (19921.
Corresponding HECs are 7.58, 34.18, and 148.7 mg/m3 for males and 7.61, 34.34, and 149.4 mg/m3 for females.
°Mean ± standard deviation.
*p < 0.05, according to the Dunnett's test reported by the study authors.
22
/t'/V-Amyl alcohol
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FINAL
5-2-2013
Table B-3. Selected Hematological Values in Male Fischer 344 Rats Exposed to tert-Amyl
Alcohol by Inhalation for 11 Weeks"
Endpoint
Exposure Concentration in ppmb
0
50
225
1000
54 Exposures
Number of animals
10
10
10
10
Packed cell volume (%)°
49.5 ± 1.4
46.4 ± 1.7*
49.3 ±2.1
49.3 ±2.0
Red blood cells (x 106/mm3)°
8.79 ±0.25
8.28 ±0.35*
8.77 ±0.30
8.91 ±0.41
Hemoglobin (g/100 mL)°
16.0 ±0.4
15.0 ±0.5*
15.8 ±0.7
15.9 ±0.6
White blood cells (x 106/mm3)°
13.3 ±2.3
12.7 ± 1.6
9.4 ±0.9*
10.0 ± 1.0*
57 Exposures
Number of animals
10
10
10
10
Packed cell volume (%)°
49.8 ± 1.3
47.4 ±0.9*
49.1 ± 1.3
48.9 ± 1.4
Red blood cells (/ 106/mm3)°
9.03 ±0.34
8.39 ±0.20*
8.75 ±0.38
8.77 ± 0.26
Hemoglobin (g/100 mL)°
16.1 ±0.5
15.5 ±0.4*
15.9 ±0.5
16.1 ±0.3
White blood cells (/ 106/mm3)°
12.3 ± 1.4
12.2 ± 1.4
12.4 ± 1.6
12.0 ± 1.5
aDow Chemical Co (19921.
bCorresponding HECs are 7.58, 34.18, and 148.7 mg/m3 for males and 7.61, 34.34, and 149.4 mg/m3 for females.
°Mean ± standard deviation.
*p < 0.05, according to the Dunnett's test reported by the study authors.
23
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-4. Selected Hematological Values in Female Fischer 344 Rats Exposed to
tert-Amyl Alcohol by Inhalation for 11 Weeks"
Endpoint
Exposure Concentration in ppmb
0
50
225
1000
55 Exposures
Number of animals
10
10
10
10
Packed cell volume (%)°
49.7 ± 1.7
47.9 ±2.0
48.6 ± 1.7
48.9 ± 1.4
Red blood cells (x 106/mm3)°
8.54 ±0.29
8.27 ±0.28
8.58 ±0.29
8.70 ±0.51
Hemoglobin (g/100 mL)°
16.2 ±0.6
16.3 ±0.5
16.5 ±0.4
16.3 ±0.4
White blood cells (x 106/mm3)°
9.6 ± 1.5
9.0 ± 1.6
8.4 ± 1.2
8.0 ±0.9*
58 Exposures
Number of animals
10
10
10
10
Packed cell volume (%)°
47.6 ± 1.1
48.5 ± 1.7
47.1 ± 1.2
46.5 ± 1.6
Red blood cells (x 106/mm3)°
8.08 ±0.26
7.80 ±0.42
7.81 ±0.36
7.83 ±0.44
Hemoglobin (g/100 mL)°
15.7 ±0.5
15.5 ±0.8
15.5 ±0.5
15.5 ±0.6
White blood cells (x 106/mm3)°
12.1 ± 1.2
10.0 ± 1.0*
11.4 ± 1.2
10.9 ± 1.2
aDow Chemical Co (19921.
bCorresponding HECs are 7.58, 34.18, and 148.7 mg/m3 for males and 7.61, 34.34, and 149.4 mg/m3 for females.
°Mean ± standard deviation.
*p < 0.05, according to the Dunnett's test reported by the study authors.
24
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-5. Selected Absolute Organ Weights in Male and Female Fischer 344 Rats
Exposed to tert-Amyl Alcohol by Inhalation for 12 Weeks"
Endpoint
Exposure Concentration in ppmb
0
50
225
1000
Males (59 exposures)
Number of animals
10
10
10
10
Fasted body weight (g)°
304 ± 13
305 ± 16 (0.33)
301 ± 14 (-0.99)
303 ± 17 (-0.33)
Kidney (g)°
2.05 ±0.11
2.06 ±0.11 (0.49)
2.07 ±0.12 (0.98)
2.09 ±0.16 (1.95)
Liver (g)c
7.48 ±0.50
7.45 ±0.51 (-0.40)
7.56 ±0.36 (1.07)
8.45 ±0.64 (12.97)*
Brain (g)°
1.88 ±0.04
1.87 ±0.05 (-0.53)
1.89 ±0.06 (0.53)
1.84 ±0.06 (-2.13)
Heart (g)°
0.80 ±0.05
0.89 ±0.07 (11.25)
0.86 ±0.07 (7.50)
0.85 ±0.07 (6.25)
Testes (g)°
3.07 ±0.10
3.02 ±0.16 (-1.63)
3.10 ±0.11 (0.98)
3.00 ±0.14 (-2.28)
Females (60 exposures)
Number of animals
10
10
10
10
Fasted body weight (g)°
160 ±6
167 ± 8 (4.38)
170 ± 7 (6.25)*
163 ±11 (-1.88)
Kidney (g)°
1.20 ±0.04
1.19 ±0.08 (-0.83)
1.27 ±0.09 (5.83)
1.14 ±0.12 (-5.00)
Liver (g)c
3.84 ±0.19
4.02 ±0.16 (4.69)
4.20 ±0.32 (9.34)*
4.02 ±0.37 (4.69)
Brain (g)°
1.70 ±0.04
1.73 ±0.05 (1.76)
1.74 ±0.03 (2.35)
1.70 ±0.09 (0)
Heart (g)°
0.50 ±0.04
0.54 ± 0.04 (8.00)
0.57 ±0.05 (14.00)
0.52 ± 0.04 (4.00)
aDow Chemical Co (19921.
bCorresponding HECs are 7.58, 34.18, and 148.7 mg/m3 for males and 7.61, 34.34, and 149.4 mg/m3 for females.
°Mean ± standard deviation (% change compared to control calculated as [ | exposed value - control value | ]
control value).
*p < 0.05, according to the Dunnett's test reported by the study authors.
25
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-6. Selected Relative Organ Weights in Male and Female Fischer 344 Rats Exposed to
tert-Amyl Alcohol by Inhalation for 12 Weeks"
Endpoint
Exposure Concentration in ppmb
0
50
225
1000
Males (59 exposures)
Number of animals
10
10
10
10
Fasted body weight (g)°
304 ± 13
305 ± 16(0.33)
301 ± 14 (-0.99)
303 ± 17 (-0.33)
Relative kidney weightc d
0.67 ±0.03
0.68 ±0.02 (1.49)
0.69 ± 0.04 (2.98)
0.69 ± 0.04 (2.99)
Relative liver weightc d
2.46 ±0.12
2.45 ±0.11 (-0.41)
2.52 ±0.10 (2.44)
2.81 ±0.10 (14.23)*
Relative brain weightc d
0.62 ±0.03
0.62 ± 0.03 (0)e
0.63 ±0.03 (1.61)
0.61 ±0.02 (-1.61)
Relative heart weightc d
0.29 ±0.01
0.29 ± 0.02 (0)
0.29 ± 0.02 (0)
0.28 ±0.01 (-3.45)
Relative testes weightc d
1.01 ±0.05
0.99 ±0.05 (-1.98)
1.03 ± 0.05 (1.98)e
0.99 ±0.04 (-1.98)
Females (60 exposures)
Number of animals
10
10
10
10
Fasted body weight (g)°
160 ±6
167 ± 8 (4.38)
170 ± 7 (6.25)*
163 ±11 (-1.88)
Relative kidney weightc d
0.75 ± 0.05
0.71 ±0.05 (—5.33)e
0.75 ± 0.04 (0)
0.70 ± 0.04 (-6.67)e
Relative liver weightc d
2.41 ± 0.11
2.41 ±0.09(0)
2.40 ±0.12 (-0.41)
2.46 ±0.11 (2.07)
Relative brain weightc d
1.07 ±0.03
1.03 ±0.04 (-3.74)
1.03 ±0.03 (-3.74)
1.05 ±0.04 (-1.87)
Relative heart weightc d
0.35 ± 0.02e
0.33 ±0.02 (-5.71)
0.34 ± 0.02 (-2.86)
0.32 ±0.02 (-8.57)*
aDow Chemical Co (19921.
bCorresponding HECs are 7.58, 34.18, and 148.7 mg/m3 for males and 7.61, 34.34, and 149.4 mg/m3 for females.
°Mean ± standard deviation (% change compared to control calculated as [ | exposed value - control value | ] control
value).
dRelative organ weights are presented as g-organ weight/100 g-body weight.
eThe legibility of the original study makes it difficult to decipher these values.
*p < 0.05, according to the Dunnett's test reported by the study authors.
26
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-7. Body-Weight Gain in Male and Female CD-I Mice Exposed to tert-Amyl
Alcohol by Inhalation for 12 Weeks"
Exposure Concentration in ppmb
Endpoint
0
50
225
1000
Males (60 exposures)
Number of animals
10
10
10
10
Body-weight gain (g)°
5.0 ±3.4
8.4 ± 4.5d
6.5 ±3.5
6.4 ±3.1
Females (61 exposures)
Number of animals
10
10
10
10
Body-weight gain (g)°
4.7 ±3.3
4.3 ±3.4
5.0 ±3.5
2.2 ±3.7
aDow Chemical Co (19921.
bCorresponding HECs are 31.8, 143.1, and 622.8 mg/m3 for males and 31.9, 143.8, and 625.9 mg/m3 for females.
°Mean ± standard deviation; calculated from the mean body weights in the study report.
dThe legibility of original study makes it difficult to decipher this value.
27
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-8. Selected Clinical Chemistry Parameters in Male and Female CD-I Mice
Exposed to tert-Amyl Alcohol by Inhalation for 12 Weeks"
Endpoint
Exposure Concentration in ppmb
0
50
225
1000
Males (60 exposures)
Number of animals
10
10
10
10
Blood urea nitrogen (mg %)°
31 ±4
24 ± 1*
24 ±4*
28 ±4
Serum alkaline phosphatase (|iUnits/mL)c
30 ±8
34 ± 19
31 ± 14
31± 18
Serum glutamic pyruvic transaminase
(|iUnits/mL)c
62 ±51
16 ± 15*
26 ± 12*
27 ± 19*
Serum glutamic oxaloacetic transaminase
(|iUnits/mL)c
63± 24
31± 12*
43± 16
53± 22
Females (61 exposures)
Number of animals
10
10
10
10
Blood urea nitrogen (mg %)°
28 ±5
26 ±3
25 ±4
27 ±4
Serum alkaline phosphatase (|iUnits/mL)c
40 ±9
40 ± 10
43 ±9
41 ± 10
Serum glutamic pyruvic transaminase
(|iUnits/mL)c
13 ±3
13 ±3
11 ± 2
11 ± 2
Serum glutamic oxaloacetic transaminase
(|iUnits/mL)c
37± 5
41± 9
39± 7
36± 6
aDow Chemical Co (19921.
bCorresponding HECs are 31.8, 143.1, and 622.8 mg/m3 for males and 31.9, 143.8, and 625.9 mg/m3 for females.
°Mean ± standard deviation.
*p <0.05, according to the Dunnett's test reported by the study authors.
28
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-9. Selected Absolute Organ Weights in Male and Female CD-I Mice Exposed to
tert-Amyl Alcohol by Inhalation for 12 Weeks"
Endpoint
Exposure Concentration in ppmb
0
50
225
1000
Males (60 exposures)
Number of animals
10
10
10
10
Fasted body weight (g)°
38 ±2
40 ± 3 (5.26)
38 ± 3 (0)
38 ± 3 (0)
Kidney (g)°
0.65 ±0.15
0.71 ±0.15 (9.23)
0.67 ±0.10 (3.08)
0.63 ±0.07 (-3.08)
Liver (g)c
2.09 ±0.24
1.86 ±0.26 (-11.00)
2.04 ± 0.27 (-2.39)
2.13 ±0.34 (1.91)
Brain (g)°
0.54 ±0.04
0.55 ±0.04 (1.85)
0.54 ± 0.02 (0)
0.55 ±0.03 (1.85)
Heart (g)°
0.18 ±0.03
0.17 ±0.03 (-5.56)
0.18 ±0.02 (0)
0.19 ±0.03 (5.56)
Testes (g)°
0.28 ±0.03
0.28 ± 0.03 (0)
0.29 ±0.04 (3.57)
0.27 ±0.02 (-3.57)
Females (61 exposures)
Number of animals
10
10
10
10
Fasted body weight (g)°
31 ± 3
30 ±3 (-3.23)
30 ±3 (-3.23)
28 ± 3 (-9.68)
Kidney (g)°
0.38 ±0.04
0.37 ±0.05 (-2.63)
0.30 ±0.03 (-21.05)
0.36 ± 0.04 (-5.26)
Liver (g)c
1.67 ±0.25
1.62 ±0.27 (-2.99)
1.54 ±0.27 (-7.78)
1.51 ±0.10 (-9.58)
Brain (g)°
0.49 ±0.03
0.49 ± 0.03 (0)
0.49 ± 0.03 (0)
0.49 ± 0.02 (0)
Heart (g)°
0.14 ±0.02
0.14 ±0.03 (0)
0.14 ±0.01 (0)
0.14 ±0.02 (0)
aDow Chemical Co (19921.
bCorresponding HECs are 31.8, 143.1, and 622.8 mg/m3 for males and 31.9, 143.8, and 625.9 mg/m3 for females.
°Mean ± standard deviation (% change compared to control calculated as [ | exposed value - control value | ]
control value).
*p < 0.05, according to the Dunnett's test reported by the study authors.
29
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-10. Selected Relative Organ Weights in Male and Female CD-I Mice Exposed to
tert-Amyl Alcohol by Inhalation for 12 Weeks"
Endpoint
Exposure Concentration in ppmb
0
50
225
1000
Males (60 exposures)6
Number of animals
10
10
10
10
Fasted body weight (g)°
38 ±2
40 ± 3 (5.26)
38 ± 3 (0)
38 ± 3 (0)
Kidney°'d
1.69 ±0.30
1.78 ±0.35 (5.33)
1.75 ±0.26 (3.55)
1.66 ±0.19 (-1.78)
Livercd
5.44 ±0.52
4.63 ± 0.44
(-14.89)*
5.28 ± 0.42 (-2.94)
5.56 ±0.67 (2.21)
Braincd
1.40 ±0.10
1.37 ±0.12 (-2.14)
1.41 ±0.08 (0.71)
1.44 ±0.14 (2.86)
Heart°'d
0.40 ± 0.06
0.43 ± 0.06 (7.50)
0.48 ± 0.05 (20.00)
0.49 ± 0.07 (22.50)
Testes°'d
0.71 ±0.09
0.71 ±0.09(0)
0.76 ± 0.06 (7.04)
0.72 ±0.09 (1.41)
Females (61 exposures)6
Number of animals
10
10
10
10
Fasted body weight (g)°
31 ± 3
30 ±3 (-3.23)
30 ±3 (-3.23)
28 ± 3 (-9.68)
Kidney°'d
1.24 ±0.09
1.23 ±0.12 (-0.81)
1.10 ±0.08
(-11.29)
1.29 ±0.10 (4.03)
Livercd
5.45 ±0.36
5.36 ±0.49 (-1.65)
5.17 ±0.48 (-5.14)
5.31 ±0.23 (-2.57)
Braincd
1.63 ±0.14
1.64 ±0.15 (0.61)
1.68 ±0.10 (3.07)
1.74 ±0.13 (6.75)
Heart°'d
0.47 ±0.05
0.45 ± 0.07 (-4.26)
0.47 ± 0.04 (0)
0.48 ±0.04 (2.13)
aDow Chemical Co (19921.
bCorresponding HECs are 31.8, 143.1, and 622.8 mg/m3 for males and 31.9, 143.8, and 625.9 mg/m3 for females.
°Mean ± standard deviation (% change compared to control calculated as [ | exposed value - control value | ]
control value).
dRelative organ weights are presented as g-organ weight/100 g-body weight.
eThe legibility of the original study makes it difficult to these decipher values.
*p < 0.05, according to the Dunnett's test reported by the study authors.
30
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-ll. Histopathology of Male CD-I Mice Exposed to tert-Amyl Alcohol by Inhalation
for 12 Weeks (60 Exposures)"
Exposure Concentration in ppmb
Endpoint
0
50
225
1000
Liver
Accentuation of hepatolobular pattern0
0/5 (0)
ND
ND
2/5 (40)
Multifocal aggregates of mononuclear cells0
0/5 (0)
ND
ND
1/5 (20)
Focal aggregation of mononuclear cells0
0/5 (0)
ND
ND
2/5 (40)d
aDow Chemical Co (19921.
bCorresponding HECs are 31.8, 143.1, and 622.8 mg/m3 for males and 31.9, 143.8, and 625.9 mg/m3 for females.
°Number of animals with endpoint/number of animals exposed (% affected).
dThe legibility of the original study makes it difficult to decipher this value.
ND = not determined.
Table B-12. Body Weight Gain in Male Beagle Dogs Exposed to tert-Amyl Alcohol by
Inhalation for 12 Weeks (61 Exposures)"
Exposure Concentration in ppm (HEC in mg/m3)b
Endpoint
0(0)
50 (31.9)
225 (143.8)
1000 (625.9)
Number of animals
4
4
4
4
Body-weight gain (kg)0
1.2 ±0.3
1.0 ±0.6
0.9 ± 1.1
1.1 ± 0.8
aDow Chemical Co (19921.
bHECEXRESp = (ppm x MW ^ 24.45) x (hours per day exposed ^ 24) x (days per week exposed ^ 87) x blood-air
partition coefficient.
°Mean ± standard deviation; calculated from the mean body weights in the study report.
31
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-13. Selected Clinical Chemistry Parameters in Male Beagle Dogs Exposed to
tert-Amyl Alcohol by Inhalation for 12 Weeks (61 Exposures)"
Endpoint
Exposure Concentration in ppm
(HEC in mg/m3)b
0(0)
50 (31.9)
225 (143.8)
1000 (625.9)
Number of animals
4
4
4
4
Blood glucose (mg %)°
94 ± 7b
120±11*
109 ± 17
107 ±7
Blood urea nitrogen (mg %)°'d
19 ±3
19 ±2
21 ± 2
18 ±4
Serum alkaline phosphatase (|iUnits/mL)c
32 ±7
39 ±6
42 ±7
99 ±52*
Serum glutamic pyruvic transaminase (|iUnits/mL)c
17 ±2
18 ±3
22 ±4
26 ±7*
aDow Chemical Co (19921.
I:,HEC|.vR|.S|, = (ppm x MW ^ 24.45) x (hours per day exposed ^ 24) x (days per week exposed ^ 87) x blood-air
partition coefficient.
°Mean ± standard deviation.
Values were measured on Day 55.
*p < 0.05, according to the Dunnett's test reported by the study authors.
Table B-14. Selected Hematology Values in Male Beagle Dogs Exposed to tert-Amyl
Alcohol by Inhalation for 11 Weeks (56 Exposures)"
Endpoint
Exposure Concentration in ppm (HEC in mg/m3)b
0(0)
50 (31.9)
225 (143.8)
1000 (625.9)
Number of animals
4
4
4
4
Packed cell volume (%)°
42.8 ±2.2
48.9 ±2.8*
49.8 ±3.5*
44.0 ±2.8
Hemoglobin (g/100 mL)°
15.5 ±0.7
17.6 ± 1.1*
18.0 ± 1.2*
16.0 ±0.6
aDow Chemical Co (1992).
bHECEXRESp = (ppm x MW ^ 24.45) x (hours per day exposed ^ 24) x (days per week exposed ^ 87) x blood-air
partition coefficient.
°Mean ± standard deviation.
*p < 0.05, according to the Dunnett's test reported by the study authors.
32
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-15. Selected Urinalysis Values in Male Beagle Dogs Before and After Exposure to
tert-Amyl Alcohol by Inhalation for 11 Weeks (55 Exposures)"
Endpoint
Exposure Concentration in ppm (HEC in mg/m3)b
0(0)
50 (31.9)
225 (143.8)
1000 (625.9)
Number of animals
4
4
4
4
Specific gravity (preexposure)0
1.032 ±0.011
1.031 ±0.011
1.026 ±0.007
1.043 ±0.011
Specific gravity (55 exposures)0
1.040 ±0.06
1.055 ±0.007
1.052 ±0.011
1.029 ±0.012*
aDow Chemical Co (19921.
bHECEXRESp = (ppm x MW ^ 24.45) x (hours per day exposed ^ 24) x (days per week exposed ^ 87) x blood-air
partition coefficient.
°Mean ± standard deviation.
*p < 0.05, according to the Dunnett's test reported by the study authors.
Table B-16. Selected Absolute Organ Weights in Male Beagle Dogs Exposed to tert-Amyl
Alcohol by Inhalation for 12 Weeks (61 Exposures)"
Endpoint
Exposure Concentration in ppm (HEC in mg/m3)b
0(0)
50 (31.9)
225 (143.8)
1000 (625.9)
Number of animals
4
3
4
4
Final body weight (kg)0
12.5 ±0.2
12.5 ±0.5 (0)
12.7 ±0.6 (1.60)
12.1 ±0.6 (-3.20)
Kidney (g)°
59.02 ±4.55
50.01 ±7.76 (-15.27)
60.52 ± 6.46 (2.54)
67.56 ±8.20 (14.47)
Liver (g)°
345.58 ±49.08
382.73 ± 17.40 (10.75)e
421.66 ±47.03 (22.02)
456.24 ± 22.97 (32.02)*
Brain (g)°
85.51 ±4.45
85.07 ±4.62 (-0.51)
80.06 ±4.12 (-6.37)
81.78 ± 1.29 (-4.36)
Heart (g)°
85.84 ±8.40d
85.57 ±6.28 (-0.31)
82.53 ± 10.63 (-3.86)
86.24 ± 7.42 (0.47)
Testes (g)°
18.31 ±1.77d
17.10 ±2.50 (-6.61)
16.41 ±0.95 (-10.38)d
18.74 ±1.70 (2.35)
aDow Chemical Co (1992).
bHECEXRESp = (ppm x MW ^ 24.45) x (hours per day exposed ^ 24) x (days per week exposed ^ 87) x blood-air
partition coefficient.
°Mean ± standard deviation (% change compared to control calculated as [ | exposed value - control value | ] control
value).
dThe legibility of the original study makes it difficult to decipher this value.
eThis average differs from what is reported in the principal study due to removal of an individual outlier, see study
summary for full explanation.
*p < 0.05, according to the Dunnett's test reported by the study authors.
33
/f/V-Amyl alcohol
-------
FINAL
5-2-2013
Table B-17. Selected Relative Organ Weights in Male Beagle Dogs Exposed to tert-Amyl
Alcohol by Inhalation for 12 Weeks (61 Exposures)"
Endpoint
Exposure Concentration in ppm (HEC in mg/m3)b
0(0)
50 (31.9)
225 (143.8)
1000 (625.9)
Number of animals
4
3
4
4
Final body weight (kg)0
12.5 ±0.2
12.5 ± 0.5 (0)
12.7 ±0.6 (1.60)
12.1 ±0.6 (-3.20)
Relative kidney weightc d
0.48 ±0.05
0.47 ± 0.06 (-2.08)
0.47 ± 0.04 (-2.08)
0.56 ±0.09 (16.67)
Relative liver weightc d
2.76 ±0.34
3.03 ±0.04 (9.78)f
3.31 ±0.28 (19.93)
3.77 ±0.20 (36.59)*
Relative brain weightc d
0.68 ±0.04
0.60 ±0.05
(—11,76)e
0.60 ±0.03 (-11.76)
0.68 ± 0.04 (0)e
Relative heart weight
0.69 ±0.03
0.60 ±0.04 (-13.04)
0.73 ± 0.05 (5.80)
0.71 ±0.04 (2.90)
Relative testes weight
0.15 ±0.01
0.14 ±0.01 (-6.67)
0.13 ±0.01 (-13.33)
0.16 ±0.02 (6.67)
aDow Chemical Co (19921.
bHECEXRESp = (ppm x MW ^ 24.45) x (hours per day exposed ^ 24) x (days per week exposed ^ 87) x blood-air
partition coefficient.
°Mean ± standard deviation (% change compared to control calculated as [ | exposed value - control value | ]
control value).
dRelative organ weights are presented as g-organ weight/100 g-body weight.
eThe legibility of the original study makes it difficult to decipher these values.
fThis average differs from what is reported in the principal study due to removal of an individual outlier, see study
summary for full explanation.
*p < 0.05, according to the Dunnett's test reported by the study authors.
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Table B-18. Selected Histopathologic and Gross Pathological Observations in the Livers
of Male Beagle Dogs Exposed to tert-Amyl Alcohol by Inhalation for 12 Weeks (61
Exposures)"
Endpoint
Exposure Concentration in ppm (HEC in mg/m3)b
0(0)
50 (31.9)
225 (143.8)
1000 (625.9)
Enlarged liver
0/4 (0)
0/4 (0)
1/4 (25)
4/4 (100)
Accentuation of the hepatolobular pattern due to
increased cytoplastic vacuolization in the
centrilobular region
3/4 (75)°
3/4 (75)°
4/4 (100)
2/4 (50)
Focal or multifocal aggregates of mononuclear
cells
2/4 (50)
0/4 (0)
0/4 (0)
0/4 (0)
Focal or multifocal aggregates of mononuclear
and polynuclear cells
2/4 (50)
0/4 (0)
1/4 (25)
0/4 (0)
Reticuloendothelial cells containing pigment
1/4 (25)
0/4 (0)
0/4 (0)
0/4 (0)
Hepatocellular cytoplasmic eosinophilic inclusion
bodies
0/4 (0)
1/4 (25)
1/4 (25)°
1/4 (25)°
Focal granulosa
0/4 (0)
0/4 (0)
2/4 (50)
2/4 (50)
aDow Chemical Co (19921.
bHECEXRESp = (ppm x MW ^ 24.45) x (hours per day exposed ^ 24) x (days per week exposed ^ 87) x blood-air
partition coefficient.
°The legibility of original study makes it difficult to decipher these values.
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APPENDIX C. BMD OUTPUTS
MODELING PROCEDURE FOR CONTINUOUS DATA
The BMD modeling of continuous data was conducted with EPA's BMDS
(version 2.1.2). For increased alkaline phosphatase activity in male beagles, all continuous
models available within the software were fit using a default BMR of 1 standard deviation from
the control mean. For increased liver weights in male rats and beagles, all continuous models
available within the software were fit using a default BMR of 10% relative risk. An adequate fit
was judged based on the goodness-of-fit p-walue {p > 0.1), magnitude of the scaled residuals in
the vicinity of the BMR, and 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-w alue < 0.1), the data set was considered unsuitable
for BMD modeling. Among all models providing adequate fit, the lowest BMCL was selected if
the BMCLs estimated from different models varied greater than 3-fold; otherwise, the BMCL
from the model with the lowest AIC was selected as a potential POD from which to derive the
screening p-RfC values.
INCREASED ABSOLUTE LIVER WEIGHT OF MALE BEAGLES TREATED WITH
tert-AMYL ALCOHOL FOR 12 WEEKS (Dow Chemical Co. 1992)
All available continuous models in BMDS (version 2.1.2) were fit to the increased
absolute liver-weight data from male beagles exposed to tert-amyl alcohol for 12 weeks (Dow
Chemical Co. 1992) (see Table B-16). For increased absolute liver weight, a BMR of a
10% change relative to the control mean was used. In addition, a BMR of 1 SD was also
estimated for comparison purposes based on U.S. EPA (2012a) BMD guidance. The
homogeneity variance (Test 2) p-w alue of greater than 0.1 indicates that constant variance is the
appropriate variance model. As assessed by the goodness-of-fit test and visual inspection, the
Hill model provided the best fit model (see Table C-l and Figure C-l). Estimated doses
associated with 10% relative risk and the 95% lower confidence limit on these doses (BMCiohec
values and BMCLiqhec values, respectively) were 33.5 and 7.83 mg/m3.
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Table C-l. Model Predictions for Absolute Liver Weight in Male Beagles"
Modelb
BMCiohec
BMCLiohec
BMCisdhec
BMCLisdhec
/7-Value
Test 2
/7-Value
Test 3
Goodness-
of-Fit
p-V alueb
AIC
Conclusion
Exponential (M2)
279
192
292
196
0.162
0.162
0.071
130.93
Goodness-of-fit p-valuc <0.1
Exponential (M3)
279
192
292
196
0.162
0.162
0.071
130.93
Goodness-of-fit p-valuc <0.1
Exponential (M4)
45.5
12.7
42.5
13.4
0.162
0.162
0.607
127.90
Exponential (M5)
45.5
12.7
42.5
13.4
0.162
0.162
0.607
127.90
Hill
33.5
7.83
31.0
8.25
0.162
0.162
0.829
127.68
Lowest BMCL
Linear
256
168
266
173
0.162
0.162
0.081
130.66
Goodness-of-fit p-valuc <0.1
Polynomial
256
168
266
173
0.162
0.162
0.081
130.66
Goodness-of-fit p-valuc <0.1
Power
256
168
266
173
0.162
0.162
0.081
130.66
Goodness-of-fit p-valuc <0.1
aDow Chemical Co (1992).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
AIC = Akaike's Information Criteria; BMC = benchmark concentration; BMCL = lower confidence limit (95%) on the benchmark concentration.
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Hill Model with 0.95 Confidence Level
dose
09:57 05/09 2012
Figure C-l. Dose-Response Modeling for Increased Absolute Liver Weight in Male Beagles
Treated with tert-Amyl Alcohol for 12 weeks (Dow Chemical Co, 1992)
Text Output for Hill BMD Model for Increased Absolute Liver Weight in Male Beagles
Treated with tert-Amyl Alcohol for 12 weeks (Dow Chemical Co, 1992)
Hill Model. (Version: 2.15; Date: 10/28/2009)
Input Data File: C:\Documents and Settings\JKaiser\Desktop\modeling
results\hil_absliv_taa_dog_dowwo5 4l_Hil-ConstantVariance-BMRlO-Restrict.(d)
Gnuplot Plotting File: C:\Documents and Settings\JKaiser\Desktop\modeling
results\hil_absliv_taa_dog_dowwo5 4l_Hil-ConstantVariance-BMRlO-Restrict.pit
Tue May 29 08:19:17 2012
BMDS Model Run
The form of the response function is:
Y[dose] = intercept + v*dose^n/(k^n + dose^n)
Dependent variable = mean
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Independent variable = dose
rho is set to 0
Power parameter restricted to be greater than 1
A constant variance model is fit
Total number of dose groups = 4
Total number of records with missing values = 0
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
alpha = 1459.13
rho = 0 Specified
intercept = 345.58
v = 110.66
n = 0.184171
k = 203.444
Asymptotic Correlation Matrix of Parameter Estimates
( *** The model parameter(s) -rho -n
have been estimated at a boundary point, or have been specified by
and do not appear in the correlation matrix )
alpha intercept v k
alpha 1 -2.5e-007 -1.3e-007 -3.8e-007
intercept -2.5e-007 1 -0.36 0.49
v -1.3e-007 -0.36 1 0.5
k -3.8e-007 0.49 0.5 1
the user,
Parameter Estimates
Interval
Variable
Limit
alpha
1841.56
intercept
377.92
v
179.824
n
k
236.249
Estimate
1073.37
346.421
123.903
1
86.2353
Std. Err.
391.941
16.071
28.5316
NA
76.5392
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.
305.185
314.923
67.9824
-63.7787
Table of Data and Estimated Values of Interest
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Dose
Obs Mean
Est Mean
Obs Std Dev Est Std Dev
Scaled Res.
0
31.9
143.8
625.9
346
383
422
456
346
380
424
455
49.1
17. 4
47
23
32 .
32 .
32 .
32 .
-0.0514
0.151
-0.135
0.0561
Model Descriptions for likelihoods calculated
Model A1: Yij = Mu(i) + e(ij)
Var{e(ij)} = SigmaA2
Model A2: Yij = Mu(i) + e(ij)
Var{e(ij)} = Sigma(i)^2
Model A3: Yij = Mu(i) + e(ij)
Var{e(ij)} = Sigma/S2
Model A3 uses any fixed variance parameters that
were specified by the user
Model R: Yi = Mu + e(i)
Var{e(i)} = Sigma^2
Likelihoods of Interest
Model
A1
A2
A3
fitted
R
Log(likelihood)
-59.815784
-57.248826
-59.815784
-59.839224
-67.241843
# Param's
5
8
5
4
2
AIC
129.631568
130.497652
129.631568
127.678448
138.483685
Explanation of Tests
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)
(Note: When rho=0 the results of Test 3 and Test 2 will be the same.)
Test
1:
Test
2 :
Test
3:
Test
4 :
Tests of Interest
Test
-2*log(Likelihood Ratio) Test df
p-value
Test
Test
Test
Test
19.986
5.13392
5.13392
0.0468793
0. 002785
0.1622
0.1622
0. 8286
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
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The modeled variance appears
The model chosen seems
to adequately describe the data
Benchmark Dose Computation
Specified effect = 0.1
Risk Type = Relative risk
Confidence level = 0.95
BMD = 33.4678
BMDL = 7.8333
The p-value for Test 3 is greater than .1.
to be appropriate here
The p-value for Test 4 is greater than .1.
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INCREASED RELATIVE LIVER WEIGHT OF MALE BEAGLES TREATED WITH
tert-AMYL ALCOHOL FOR 12 WEEKS (Dow Chemical Co. 1992)
All available continuous models in BMDS (version 2.1.2) were fit to the increased
relative liver-weight data from male beagles exposed to tert-amyl alcohol for 12 weeks (Dow
Chemical Co. 1992) (see Table B-17). For increased relative liver weight, a BMR of a
10% change relative to the control mean was used. In addition, a BMR of 1 SD was also
estimated for comparison purposes based on EPA BMD guidance (U.S. EPA. 2012a). The BMD
analysis resulted in significant lack of fit (goodness-of-fit p < 0.10, Test 4) for all continuous
models employing constant variance. No available model in BMDS provided an adequate fit to
the data as Test 3 for all models was less than 0.1 (see Table C-2). All of the BMD modeling
results shown in Table C-2 were obtained from nonconstant variance models. Because all
models for these data failed, a BMD output graph is not provided.
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Table C-2. Model Predictions for Relative Liver Weight in Male Beagles"
Modelb
BMCiohec
BMCL10hec
BMCisdhec
BMCL1SDHec
/7-Value
Test 2
/7-Value
Test 3
Goodness-of-
Fit />-Valucb
AIC
Conclusion
Exponential (M2)
244
187
243
156
0.020
0.010
0.092
-18.79
p-score 3 < 0.1
Exponential (M3)
244
187
243
156
0.020
0.010
0.092
-18.79
p-score 3 < 0.1
Exponential (M4)
63.5
29.9
56.1
24.4
0.020
0.010
0.394
-20.82
p-score 3 < 0.1
Exponential (M5)
63.5
29.9
56.1
24.4
0.020
0.010
0.394
-20.82
p-score 3 < 0.1
Hill
54.0
18.4
47.4
21.5
0.020
0.010
0.464
-21.01
p-score 3 < 0.1
Linear
221
162
218
132
0.020
0.010
0.111
-19.15
p-score 3 < 0.1
Polynomial
221
162
218
132
0.020
0.010
0.111
-19.15
p-score 3 < 0.1
Power
221
162
218
132
0.020
0.010
0.111
-19.15
p-score 3 < 0.1
aDow Chemical Co (1992).
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
AIC = Akaike's Information Criteria; BMC = benchmark concentration; BMCL = lower confidence limit (95%) on the benchmark concentration.
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INCREASED ALKALINE PHOSPHATASE IN MALE BEAGLES TREATED WITH
tert-AMYL ALCOHOL FOR 12 WEEKS (Dow Chemical Co. 1992)
All available continuous models in BMDS (version 2.1.2) were fit to the increased
alkaline phosphatase data from male beagles exposed to tert-amyl alcohol for 12 weeks (Dow
Chemical Co. 1992) (see Table B-13). The homogeneity variance (Test 2)/>-value of less than
0.1 indicates that nonconstant variance is the appropriate variance model. As assessed by the
goodness-of-fit test and visual inspection, the Exponential 2 model provided the best fit model
(see Table C-3 and Figure C-2). Estimated doses associated with 10% relative risk and the
95% lower confidence limit on these doses (BMCisdhec values and BMCLisdhec values,
respectively) were 87.4 and 57.8 mg/m3.
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Table C-3. Model Predictions for Alkaline Phosphatase in Male Beagles"
Modelb
BMCisdhec
BMCL1SDHec
/7-Value
Test 2b
/7-Value
Test 3b
Goodness-of-Fit
p-V alueb
AIC
Conclusion
Exponential (M2)
87.4
57.8
<0.0001
0.500
0.483
99.32
Lowest acceptable AIC
Exponential (M3)
108
58.0
<0.0001
0.500
0.237
101.26
Exponential (M4)
59.3
34.1
<0.0001
0.500
0.100
102.56
Exponential (M5)
132
37.9
<0.0001
0.500
NDr
103.53
Hill
132
NDr
<0.0001
0.500
NDr
103.53
BMCL not calculated
Power
132
37.9
<0.0001
0.500
<0.0001
101.53
Goodness-of-fit p-valuc <0.1
Polynomial
1.72 x 10~6
NDr
<0.0001
0.500
<0.0001
8
Goodness-of-fit p-valuc <0.1, BMCL
not calculated
Linear
-9999
29.2
<0.0001
0.500
0.196
36.10
aDow Chemical Co (19921.
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
AIC = Akaike's Information Criteria; BMC = benchmark concentration; BMCL = lower confidence limit (95%) on the benchmark concentration; NDr = not
determinable.
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Exponential Model 2 with 0.95 Confidence Level
09:27 05/10 2012
Figure C-2. Dose-Response Modeling for Increased Alkaline Phosphatase in Male Beagles
Treated with tert-Amyl Alcohol for 12 weeks (Dow Chemical Co, 1992)
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INCREASED ABSOLUTE LIVER WEIGHT OF MALE RATS TREATED WITH
tert-AMYL ALCOHOL FOR 12 WEEKS (Dow Chemical Co. 1992)
All available continuous models in BMDS (version 2.1.2) were fit to the increased
absolute liver-weight data from male rats exposed to tert-amyl alcohol for 12 weeks (Dow
Chemical Co. 1992) (see Table B-5). For increased absolute liver weight, a BMR of a
10% change relative to the control mean was used. In addition, a BMR of 1 SD was also
estimated for comparison purposes based on U.S. EPA (2012a) BMD guidance. The
homogeneity variance (Test 2) />value of greater than 0.1 indicates that constant variance is the
appropriate variance model. As assessed by the goodness-of-fit test and visual inspection, the
Exponential 2 model provided the best fit model (see Table C-4 and Figure C-3). Estimated
doses associated with 10% relative risk and the 95% lower confidence limit on these doses
"3
(BMCiohec values and BMCLiqhec values, respectively) were 110 and 84.0 mg/m .
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Table C-4. Model Predictions for Absolute Liver Weight in Male Rats"
Modelb
BMCiohec
BMCL10hec
BMCisdhec
BMCL1SDHec
/7-Value
Test 2
/7-Value
Test 3
Goodness-of-Fit
p-V alueb
AIC
Conclusion
Exponential (M2)
110
84.0
73.4
55.0
0.367
0.367
0.798
-11.29
Lowest acceptable
AIC
Exponential (M3)
126
85.6
96.4
56.1
0.367
0.367
0.857
-9.71
Exponential (M4)
108
80.7
71.1
52.2
0.367
0.367
0.467
-9.21
Exponential (M5)
45.8
35.8
42.2
34.6
0.367
0.367
NDr
-7.72
Hill
48.1
36.5
42.7
34.8
0.367
0.367
NDr
-7.72
Linear
108
80.7
71.1
52.2
0.367
0.367
0.768
-11.21
Polynomial
127
82.7
98.8
53.6
0.367
0.367
0.837
-9.70
Power
125
82.8
95.6
53.6
0.367
0.367
0.858
-9.71
aDow Chemical Co (19921.
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
AIC = Akaike's Information Criteria; BMC = benchmark concentration; BMCL = lower confidence limit (95%) on the benchmark concentration; NDr = not
determinable.
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Exponential Model 2 with 0.95 Confidence Level
dose
09:25 12/13 2012
Figure C-3. Dose-Response Modeling for Increased Absolute Liver Weight in Male Rats
Treated with tert-Amyl Alcohol for 12 weeks (Dow Chemical Co, 1992)
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INCREASED RELATIVE LIVER WEIGHT OF MALE RATS TREATED WITH
tert-AMYL ALCOHOL FOR 12 WEEKS (Dow Chemical Co. 1992)
All available continuous models in BMDS (version 2.1.2) were fit to the increased
relative liver-weight data from male rats exposed to tert-amyl alcohol for 12 weeks (Dow
Chemical Co. 1992) (see Table B-6). For increased relative liver weight, a BMR of a
10% change relative to the control mean was used. In addition, a BMR of 1 SD was also
estimated for comparison purposes based on U.S. EPA (2012a) BMD guidance. The
homogeneity variance (Test 2) />value of greater than 0.1 indicates that constant variance is the
appropriate variance model. As assessed by the goodness-of-fit test and visual inspection, the
Exponential 2 model provided the best fit (see Table C-5 and Figure C-4). Estimated doses
associated with 10% relative risk and the 95% lower confidence limit on these doses (BMCiohec
values and BMCLiqhec values, respectively) were 102 and 86.6 mg/m3.
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Table C-5. Model Predictions for Relative Liver Weight in Male Rats"
Modelb
BMCiohec
BMCL10hec
BMCisdhec
BMCL1SDHec
p-Value
Test 2
/7-Value
Test 3
Goodness-of-
Fit />-Valucb
AIC
Conclusion
Exponential (M2)
102
86.6
44.2
35.4
0.925
0.925
0.8275
-136.02
Lowest
acceptable AIC
Exponential (M3)
108
86.9
51.5
35.5
0.925
0.925
0.6178
-134.15
Exponential (M4)
99.7
83.3
42.0
33.3
0.925
0.925
0.5008
-133.95
Exponential (M5)
40.9
35.9
36.0
24.7
0.925
0.925
NDr
-132.35
Hill
43.8
36.5
36.4
24.6
0.925
0.925
NDr
-132.35
Linear
99.7
83.3
42.0
33.3
0.925
0.925
0.7972
-135.95
Polynomial
109
83.7
51.0
33.5
0.925
0.925
0.5891
-134.11
Power
107
83.9
51.0
33.5
0.925
0.925
0.6269
-134.16
aDow Chemical Co (19921.
bValues <0.10 fail to meet conventional goodness-of-fit criteria.
AIC = Akaike's Information Criteria; BMC = benchmark concentration; BMCL = lower confidence limit (95%) on the benchmark concentration; NDr = not
determinable.
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Exponential Model 2 with 0.95 Confidence Level
dose
17:05 12/06 2012
Figure C-4. Dose-Response Modeling for Increased Relative Liver Weight in Male Rats
Treated with tert-Amyl Alcohol for 12 weeks (Dow Chemical Co, 1992)
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APPENDIX D. REFERENCES
ACGIH (American Conference of Governmental Industrial Hygienists). (201 1). 201 1 TLVs and
BEIs: Based on the documentation of the threshold limit values for chemical substances
and physical agents and biological exposure indices. Cincinnati, OH.
http ://www. acgih.org/ store/Product Detai 1. cfm?id=2147
Am berg. A; Bernauer. U; Scheutzow, D; Dekant, W. (1999). Biotransformation of [12C]- and
[13C]-tert-amyl methyl ether and tert-amyl alcohol. Chem Res Toxicol 12: 958-964.
Am berg. A; Rosner, E; Dekant W. (2000). Biotransformation and kinetics of excretion of tert-
amyl-methyl ether in humans and rats after inhalation exposure. Toxicol Sci 55: 274-283.
AT SDR (Agency for Toxic Substances and Disease Registry). (201 1). Toxicological profiles:
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