TECHNICAL REPORT DATA
(float rtfd/ivtnictioni on ike rtvtru before completing)
1. REPORT NO.
EPA/600/8-89/099
2.
3. RECIPIENT'S ACCESSION NO
PB90-142514/AS
4. TITLE AND SUBTITLE
Updated Health Effects Assessment for Chlorobenzene
•. REPORT PATE
i. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
. PERFORMING ORGANIZATION REPORT NO
PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Criteria and Assessment Office
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati. OH 45268
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/22
»5 SUPPLEMENTARY NOTES
16. ABSTRACT
This report summarizes and evaluates information relevant to a preliminary interim
assessment of adverse health effects associated with specific chemicals or compounds.
The Office of Emergency and Remedial Response (Superfund) uses these documents in
preparing cost-benefit analyses under Executive Order J2991 for decision-making under
CERCIA. All estimates of acceptable intakes and carcinogenic potency presented in
this document should be considered as preliminary and reflect limited resources
allocated to this project. The intent in these assessments is to suggest acceptable
exposure levels whenever sufficient data are available. The interim values presented
reflect the relative degree of hazard associated with exposure or risk to the
chemical(s) addressed. Whenever possible, two categories of values have been
estimated for systemic toxicants (toxicants for which cancer is not the endpoint of
concern). The first, RfDs or subchronic reference dose, is an estimate of an exposure
level that would not be expected to cause adverse effects when exposure occurs during
a limited time interval. The RfD is an estimate of an exposure level that would not
be expected to cause adverse effects when exposure occurs for a significant portion
of the lifespan. For compounds for which there is sufficient evidence of
carcinogenicity, qi*s have been computed, if appropriate, based on oral and
inhalation data if available.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATi Field/Group
I. DISTRIBUTION STATEMENT
Public
IB. SECURITY CLASS (THu Report/
Unclassified
21. NO. OF PAGES
20. SECURITY CLASS fTTiu ftfej
Unclassified
23. PRICE
EPA F«n» 2230.1 (••«. 4-77) PRKVIOUI KOITIOM >• OMOLKTC
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EPA/600/8-89/099
January, 1989
HEALTH EFFECTS ASSESSMENT
FOR CHLOROBENZENE
ENVIRONMENTAL CRITERIA AND ASSESSMENT OFFICE
OFFICE OF HEALTH AND ENVIRONMENTAL ASSESSMENT
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
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DISCLAIMER
This document has been reviewed 1n accordance with the U.S. Environ-
mental Protection Agency's peer and administrative review policies and
approved for publication. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
11
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PREFACE
This report summarizes and evaluates Information relevant to a prelimi-
nary Interim assessment of adverse health effects associated with chloro-
benzene. All estimates of acceptable Intakes and carcinogenic potency
presented 1n this document should be considered as preliminary and reflect
limited resources allocated to this project. Pertinent toxlcologlc and
environmental data were located through on-line literature searches of the
TOXLINE, CANCERLINE and the CHEMFATE/DATALOG data bases. The basic litera-
ture searched supporting this document Is current up to May, 1987. Secon-
dary sources of Information have also been relied upon In the preparation of
this report and represent large-scale health assessment efforts that entail
extensive peer and Agency review. The following Office of Health and
Environmental Assessment (OHEA) sources have been extensively utilized:
U.S. EPA. 1980a. Ambient Water Quality Criteria for Chlorinated
Benzenes. Prepared by the Office of Health and Environmental
Assessment, Environmental Criteria and Assessment Office, Cincin-
nati, OH, for the Office of Water Regulations and Standards,
Washington, DC. EPA 440/5-80-028. NTIS PB 81-117392.
U.S. EPA. 1982a. Hazard Profile for Chlorobenzene. Prepared by
the Office of Health and Environmental Assessment, Environmental
Criteria and Assessment Office, Cincinnati, OH, for the Office of
Solid Waste, Washington, DC. EPA 600/8-84-015F. NTIS PB 85-15033.
U.S. EPA. 1985a. Health Assessment Document for Chlorinated
Benzenes. Office of Health and Environmental Assessment, Environ-
mental Criteria and Assessment Office, Cincinnati, OH. EPA
600/8-84-015F. NTIS PB 85-150332.
The Intent 1n these assessments 1s to suggest acceptable exposure levels
for noncarclnogens and risk cancer potency estimates for carcinogens
whenever sufficient data were available. Values were not derived or larger
uncertainty factors were employed when the variable data were limited 1n
scope tending to generate conservative (I.e., protective) estimates.
Nevertheless, the Interim values presented reflect the relative degree of
hazard or risk associated with exposure to the chemlcal(s) addressed.
Whenever possible, two categories of values have been estimated for
systemic toxicants (toxicants for which cancer 1s not the endpolnt of
concern). The first, RfD$ (formerly AIS) or subchronlc reference dose, 1s
an estimate of an exposure level that would not be expected to cause adverse
effects when exposure occurs during a limited time Interval (I.e., for an
Interval that does not constitute a significant portion of the Hfespan).
This type of exposure estimate has not been extensively used, or rigorously
defined, as previous risk assessment efforts have been primarily directed
towards exposures from toxicants 1n ambient air or water where lifetime
exposure 1s assumed. Animal data used for RFD$ estimates generally
Include exposures with durations of 30-90 days. Subchronlc human data are
rarely available. Reported exposures are usually from chronic occupational
exposure situations or from reports of acute accidental exposure. These
values are developed for both Inhalation (RfD$j) and oral (RfDso)
exposures.
111
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The RfD (formerly AIC) Is similar 1n concept and addresses chronic
exposure. It 1s an estimate of an exposure level that would not be expected
to cause adverse effects when exposure occurs for a significant portion of
the Hfespan [see U.S. EPA (1980b) for a discussion of this concept]. The
RfD Is route-specific and estimates acceptable exposure for either oral
(RfDo) or Inhalation (RfDj) with the Implicit assumption that exposure
by other routes Is Insignificant.
Composite scores (CSs) for noncarclnogens have also been calculated
where data permitted. These values are used for Identifying reportable
quantities and the methodology for their development Is explained In U.S.
EPA (1984).
For compounds for which there 1s sufficient evidence of carclnogenlclty
RfD§ and RfD values are not derived. For a discussion of risk assessment
methodology for carcinogens refer to U.S. EPA (1980b). Since cancer 1s a
process that Is not characterized by a threshold, any exposure contributes
an Increment of risk. For carcinogens, q-)*s have been computed, 1f appro-
priate, based on oral and Inhalation data If available.
1v
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ABSTRACT
In order to place the risk assessment evaluation In proper context,
refer to the preface of this document. The preface outlines limitations
applicable to all documents of this series as well as the appropriate
Interpretation and use of the quantitative estimates presented.
The liver and kidneys appear to be target organs for chlorobenzene
toxldty. Three separate subchronlc oral exposure studies (one using dogs,
two using rats) define comparable NOELs. The observed adverse effects
Indicated a higher sensitivity of the dog to chlorobenzene than the rat.
Based on these findings, the highest experimental NOEL of 27.3 mg/kg/day
from the dog study (Monsanto Company, 1967a) was considered appropriate to
derive an RfDgQ and RfDg. The estimated RfD$o 1s 14 mg/day, estimated
by applying an uncertainty factor of 100 (10 to extrapolate from animals to
human and another factor of 10 to account for human variability) and a
conversion factor of 5/7 (to adjust for partial weekly exposure). The
RfOg of 1.4 mg/day was derived by applying an uncertainty factor of 1000
(10 to extrapolate from subchronlc to chronic exposure, 10 to extrapolate
from animals to human and 10 to account for human variability) and a
conversion factor of 5/7 (to account for partial weekly exposure) to the dog
experimental NOEL of 27.3 mg/kg/day. This chronic oral RfD value was veri-
fied by the U.S. EPA RfD Workgroup on 01/19/89. A CS of 8 was calculated
for the low blood sugar levels, vomiting, diarrhea and conjunctivitis
observed 1n dogs at 55 mg/kg/day.
Subchronlc Inhalation data from several species are available, but
chronic Inhalation exposure assessments for chlorobenzene are lacking. An
RfD$i for Inhalation exposure of 3 mg/day has been estimated for Interim
purposes, based upon the lowest subchronlc LOAEL (75 ppm) reported In rats
(Dllley, 1977). An Interim RfDj of 0.3 mg/day was estimated by applying
an additional safety factor of 10 to extrapolate from subchronlc to chronic
exposure.
Chlorobenzene 1s placed In EPA Group D, I.e., not classifiable as to
human carclnogenlclty based on the Inadequate carcinogenic evidence 1n
experimental animals and lack of data on ep1dem1olog1cal studies.
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ACKNOWLEDGEMENTS
The Initial draft of this report was prepared by Syracuse Research
Corporation under Contract No. 68-03-3112 for EPA's Environmental Criteria
and Assessment Office, Cincinnati, OH. Dr. Christopher DeRosa and Karen
Blackburn were the Technical Project Monitors and Helen Ball was the Project
Officer. The final documents 1n this series were prepared for the Office of
Emergency and Remedial Response, Washington, DC.
Scientists from the following U.S. EPA offices provided review comments
for this document series:
Environmental Criteria and Assessment Office, Cincinnati, OH
Carcinogen Assessment Group
Office of A1r Quality Planning and Standards
Office of Solid Waste
Office of Toxic Substances
Office of Drinking Water
Editorial review for the document series was provided by the following:
Judith Olsen and Erma Durden
Environmental Criteria and Assessment Office
Cincinnati, OH
Technical support services for the document series was provided by the
following:
Bette Zwayer, Pat Daunt, Karen Mann and Jacky Bohanon
Environmental Criteria and Assessment Office
Cincinnati, OH
v1
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TABLE OF CONTENTS
1.
2.
3.
4.
5.
6.
7.
ENVIRONMENTAL CHEMISTRY AND FATE
ABSORPTION FACTORS IN HUMANS AND EXPERIMENTAL ANIMALS . . .
2.1. ORAL
2.2. INHALATION
TOXICITY IN HUMANS AND EXPERIMENTAL ANIMALS
3.1. SUBCHRONIC
3.1.1. Oral
3.1.2. Inhalation
3.2. CHRONIC
3.2.1. Oral
3.2.2. Inhalation
3.3. TERATOGENICITY AND OTHER REPRODUCTIVE EFFECTS. . . .
3.4. TOXICANT INTERACTIONS
CARCINOGENICITY
4.1. HUMAN DATA
4.2. BIOASSAYS
4.3. OTHER RELEVANT DATA
4.4. WEIGHT OF EVIDENCE ......
REGULATORY STANDARDS AND CRITERIA
RISK ASSESSMENT
6.1. SUBCHRONIC REFERENCE DOSE (RfDs)
6.1.1. Oral (RfDso)
6.1.2. Inhalation (RfDSi)
6.2. REFERENCE DOSE (RfD-)
6.2.1. Oral (RfD0)
6.2.2. Inhalation (RfDj)
6.3. CARCINOGENIC POTENCY (q-|*)
6.3.1. Oral
6.3.2. Inhalation
REFERENCES
Page
1
. . . 3
. . . 3
, , , 3
4
, , , 4
. . . 4
8
, , , 11
. . . 11
. . . 12
. . . 13
. . . 14
. . . 15
. . . 15
. . . 15
. . . 17
, , , 19
. . . 21
, , 23
. . . 23
. . . 23
. , . 24
25
. . . 25
. . . 26
. , , 26
. . . 26
. . . 27
. . . 28
APPENDIX: Summary Table for Chlorobenzene ............... 36
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LIST OF TABLES
No.
3-1
3-2
4-1
4-2
5-1
Title
Subchronlc Oral Toxlclty of Chlorobenzene In Experimental
Animals
Subchronlc Inhalation Toxlclty of Chlorobenzene 1n
Experimental Animals
Statistical Comparisons of Liver Tumors 1n Male Rats
Treated with Chlorobenzene
Mutagenldty Testing of Chlorobenzene
Current Regulatory Standards and Criteria for
Chlorobenzene .
Paqe
5
9
16
18
. 22
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LIST OF ABBREVIATIONS
BCF Bloconcentratlon factor
CAS Chemical Abstract Service
CNS Central nervous system
CS Composite score
DNA Deoxyr1bonucle1c acid
GGTP f-Glutamyl transpeptldase
K Soil sorptlon coefficient
K Octanol/water partition coefficient
ow
LOAEL Lowest-observed-adverse-effect level
MED Minimum effective dose
NOAEL No-observed-adverse-effect level
NOEL No-observed-effect level
ppm Parts per million
RfD Reference dose
RfD, Inhalation reference dose
RfD0 Oral reference dose
Subchronlc reference dose
Subchronlc Inhalation reference dose
RfDso Chronic oral reference dose
RV. Dose-rating value
RV Effect-rating value
SAP Serum alkaline phosphatase
SGOT Serum glutamlc oxalacetlc transamlnase
SGPT Serum glutamlc pyruvlc transamlnase
STEL Short-term exposure limit
TLV Threshold limit value
TWA Time-weighted average
1x
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1. ENVIRONMENTAL CHEMISTRY AND FATE
The relevant physical and chemical properties and environmental fate of
chlorobenzene (CAS No. 108-90-7) are as follows:
Chemical class:
Molecular weight:
Vapor pressure:
Water solubility:
Kow:
Soil mobility
(predicted as retardation
factor for soil depth of
140 cm and organic carbon
content of 0.087X):
BCF:
monocycllc aromatic (purgeable aromatic)
112.56
11.7 mm Hg at 20°C (Mabey et al., 1981)
466.3 mg/8, at 20°C (Horvath, 1982)
692 (Hansch and Leo, 1985)
Half-lives 1n A1r:
Water:
1.9 (WHson et al., 1981)
126 (Sabljlc, 1984)
45.7 [Rainbow trout (muscle); Salmo
qalrdnerll (Branson, 1978)
446.7 (Fathead minnow; Plmephales
promelas) (Velth et al., 1979)
~9 days (Singh et al., 1981)
0.3 days 1n river (estimated)
(Zoeteman et al., 1980)
Chlorobenzene has low solubility 1n water (Horvath, 1982). Despite the
low vapor pressure, chlorobenzene Is expected to evaporate quickly from
water as a result of high activity coefficients In water (U.S. EPA, 1985a).
B1odegradat1on may also occur during warmer weather and will proceed more
rapidly In freshwater than 1n estuaMne or marine ecosystems (NLM, 1987). A
moderate amount of adsorption to suspended solids and sediments 1s expected
(U.S. EPA, 1985a).
0040H
-1-
05/02/88
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The half-life of chlorobenzene In soil could not be located In the
available literature; however, evaporation 1s expected to be the predominant
loss mechanism from the soil surface (Wilson et al., 1981). The half-life
for evaporation from soil should be longer than Us evaporation half-life In
water. In subsurface soil, chlorobenzene blodegrades very slowly or not at
all. This compound Is adsorbed moderately onto organic soil; If retained
long enough, It may blodegrade. If soil 1s sandy or low In organic content,
chlorobenzene will be relatively mobile and 1s expected to percolate Into
groundwater (NLM, 1987).
In the atmosphere, reaction with photochemically generated hydroxyl
radicals 1s expected to be the predominant removal mechanism (Singh et al.,
1981; NLM, 1987). Reaction In polluted air containing NOX should be
somewhat faster than In clean air (NLM, 1987). Global distribution of
chlorobenzene 1n air has been suggested because chlorobenzene may be trans-
ported long distances from Us emission sources (U.S. EPA, 1985a).
0040H -2- 05/02/88
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2. ABSORPTION FACTORS IN HUMANS AND EXPERIMENTAL ANIMALS
2.1. ORAL
Quantitative studies regarding absorption of chlorobenzene In humans or
laboratory animals following 1ngest1on were not located 1n the available
literature. Reports of toxic effects 1n humans following Ingestlon or
Inhalation (Reich, 1934; Rosenbaum et al., 1947; Tarkhova, 1965) Indicated
absorption by these routes. Delchmann (1981) reported that chlorobenzene
absorption from the gastrointestinal tract was facilitated by Ingestlon of
fats and oils. Studies of the metabolism of chlorobenzene 1n several
mammalian species Indicated that absorption from the gastrointestinal tract
occurred readily (Williams, 1959).
2.2. INHALATION
No quantitative studies regarding absorption In humans or experimental
animals following Inhalation exposure to chlorobenzene could be located In
the available literature. Delchmann (1981) stated that chlorobenzene was
absorbed rapidly from the lungs. No supporting data accompanied this
statement.
0040H -3- 01/19/89
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3. TOXICITY IN HUMANS AND EXPERIMENTAL ANIMALS
3.1. SUBCHRONIC
3.1.1. Oral. No reports of subchronlc oral exposure of humans to chloro-
benzene could be located 1n the available literature. Table 3-1 summarizes
pertinent subchronlc oral exposure data 1n laboratory animals. Most of
these data were taken from summaries provided by U.S. EPA (1980a, 1985a) and
NTP (1985). The studies reviewed by these authors seem to define similar
NOELs: Monsanto Company (1967a) found no effects 1n dogs exposed by capsule
to 27.3 mg/kg/day. Following dietary exposure for 93-99 days, no effects
were reported In rats at 50 mg/kg/day (Monsanto Company, 1967b), although
slightly and Inconstantly elevated liver and kidney weights were reported at
this level 1n the published version of this study (Knapp et al., 1971).
Irish (1963) found no effects 1n rats given 14.4-18.8 mg/kg/day, 5 days/week
for 192 days.
A study by Varshavskaya (1967) described CNS, liver, hematopoletlc and
endocrine effects 1n groups of seven male rats exposed to 0.01 and 0.1 mg
chlorobenzene/kg/day by gavage. The U.S. EPA (1980a) considered the results
of Varshavskaya (1967) to be questionable primarily because these data
suggested effects at dosages far lower than those Indicated by other Inves-
tigators (see Table 3-1). Also, data generated by HolUngsworth et al.
(1956) 1n a similar study of the toxlclty of o-d1chlorobenzene Indicated
similar effects, but were associated with dosages >3 orders of magnitude
greater than those reported by Varshavskaya (1967).
The NTP (1985) conducted range-finding studies In which groups of 10/sex
F344/N rats and 10/sex B6C3F1 mice were treated with 0, 60, 125, 250, 500 or
750 mg/kg chlorobenzene by gavage on 5 days/week for 13 weeks. The dosages
were 0, 42.9, 89.3, 178.6, 357 and 538 mg/kg/day, respectively, when
0040H -4- 01/27/89
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adjusted for the Intermittent exposure (5 days/week). Body weight,
urlnalysls Indices, hematology Indices, clinical chemistry Indices, organ
weights and histology of numerous tissues were evaluated 1n all animals.
Treatment-related effects were not observed at 42.9 or 89.3 mg/kg/day 1n
rats; however, at 42.9 mg/kg/day one male mouse developed hepatic necrosis,
and at 89.3 mg/kg/day male mice had Increased liver weight and one male
mouse also had symptoms of hepatic necrosis (see Table 3-1).
Effects 1n the rats Included decreased survival and lymphold depletions
of the thymus and spleen at 538 mg/kg/day, and decreased body weight gain,
nephropathy, myelold depletion of the bone marrow, and scattered alterations
In urinary and clinical chemistry, hematology, organ weight and porphyrln
metabolism at >357 mg/kg/day (NTP, 1985). Dose-dependent hepatocellular
necrosis occurred at >178.6 mg/kg.
In mice, decreased body weight gain, survival, dose-dependent hepato-
cellular necrosis, nephropathy, thymlc necrosis and lymphold or myelold
depletion of the thymus, spleen and bone marrow occurred at >178.6 mg/kg.
In conclusion, the results of the 13-week studies largely corroborate the
earlier reports that chlorobenzene exposure can adversely affect the liver,
kidneys and hematopoletlc system. Male mice appeared to be affected more
severely than females In the 13-week study conducted by NTP (1985).
3.1.2. Inhalation. No studies regarding subchronlc Inhalation exposure
of humans to chlorobenzene could be located In the available literature.
Because of the potential for occupational exposure being long-term, these
reports are discussed In Section 3.2.2.
Several studies of subchronlc Inhalation exposure of laboratory animals
to chlorobenzene have been reviewed by Delchmann (1981) and U.S. EPA (1985a)
and are summarized 1n Table 3-2. Dllley (1977) demonstrated small, focal
0040H -8- 01/27/89
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lesions In the adrenal cortex and kidney tubules and decreased SGOT 1n rats
exposed to 75 ppm chlorobenzene 7 hours/day, 5 days/week for 120 days. This
dosage, which corresponds to an Intake of 46 mg/kg/day, defined a LOAEL In
rats from Inhalation exposure to chlorobenzene. In an earlier study, no
effects were seen In rats exposed to 122 mg/kg bw/day for 44 days (Irish,
1963).
Several reports from the foreign literature Indicate effects 1n rats at
exposures leading to dosages far below those associated with no effects In
reports from the domestic literature. For example, Khanln (1977) reported
histopathologlcal lesions In several organs at 0.06 mg/kg bw/day. Neuro-
muscular dysfunction was reported In rats at exposures leading to dosages of
0.06-4 mg/kg bw/day (Tarkhova, 1965; Plslaru, 1960; Gabor and Raucher, 1960).
In the absence of additional corroborating evidence from other laboratories,
the data are not considered reliable for use In risk assessment.
In subchronlc Inhalation experiments 1n other species, no adverse
effects were observed In rabbits at 38-126 mg/kg bw/day (Dllley, 1977;
Irish, 1963), In guinea pigs at 91 mg/kg bw/day (Irish, 1963) or In dogs at
45 mg/kg bw/day (Monsanto Company, 1978). Dogs appear to be the most
sensitive species tested, however, as weight loss and morlbundHy occurred
1n this species by 31 days of exposure to 91 mg/kg bw/day (Monsanto Company,
1978).
3.2. CHRONIC
3.2.1. Oral. No reports of chronic oral exposure of humans to chloro-
benzene were located 1n the available literature. An NTP (1985) cardno-
genldty bloassay was conducted In which groups of 50 F344/N rats/sex and 50
female B6C3F1 mice were treated with chlorobenzene In corn oil by gavage at
doses of 0, 60 or 120 mg/kg on 5 days/week for 103 weeks. Groups of 50 male
B6C3F1 mice were treated similarly at doses of 0, 30 or 60 mg/kg.
0040H -11- 01/19/89
-------
Both untreated and vehicle-treated controls were maintained. Statistically
significant reduced survival occurred 1n the low- and high-dose male mice
(56% and 58% at the end of the study, respectively, vs. 78% In the vehicle
controls) and high-dose male rats (52% vs. 78%), but there were no
treatment-related clinical signs of toxldty, decreases 1n body weight gain
or nonneoplastlc lesions. Treated rats showed "equivocal evidence for mild
chlorobenzene-lnduced hepatocellular necrosis" that was not considered to be
clear evidence of hepatotoxldty. Neoplastlc nodules, but not tumors,
occurred at a significantly Increased Incidence 1n the high-dose male rats
(Section 4.2.), but this was not suggested as a cause of the reduced
survival.
3.2.2. Inhalation. The only available reports of chronic human exposure
to chlorobenzene were summaries by U.S. EPA (1985a) from which this
discussion was adapted. Glrard et al. (1969) reported the case of a
70-year-old woman exposed for 6 years to a glue containing 70%
chlorobenzene. From the time she began using the glue, she experienced
headaches and Irritation of the mucosa of the upper respiratory tract and
eyes. After 6 years, she had developed medullary aplasla. Exposure was not
quantified.
Rosenbaum et al. (1947) examined 28 factory workers, many of whom
complained of headaches and showed signs of somnolescence and dyspepsia.
Other complaints Included tingling, numbness and stiffness of the extremi-
ties (8 workers), hyperesthesla of the hands (4 workers), and spastic
contractions of the finger muscles (9 workers) or of the gastrocnemlus (2
workers). These workers had reportedly been exposed for 1-2 years, but
details of exposure were not specified. No neurotoxlc signs were displayed
by 26 workers exposed to chlorobenzene alone or combination of benzene and
chlorobenzene for <1 year.
0040H -12- 01/19/89
-------
No reports of chronic Inhalation exposure of laboratory animals to
chlorobenzene could be located 1n the available literature.
3.3. TERATOGENICITY AND OTHER REPRODUCTIVE EFFECTS
Groups of 32-33 pregnant Fischer 344 rats and 30 pregnant New Zealand
White rabbits were exposed to 0, 75, 210 or 590 ppm of 99.982% pure
chlorobenzene by Inhalation for 6 hours/day on days 6-15 (rats) or 6-18
(rabbits) of gestation (John et al., 1984). Standard teratologlc evalua-
tions, Including soft tissue and skeletal examinations, were conducted on
gestation day 21 1n the rats and gestation day 29 In the rabbits.
Maternal toxlclty, evidenced by decreased body weight gain on gestation
days 6-8 and Increased absolute and relative liver weights, occurred In the
rats exposed to 590 ppm (John et al., 1984). Delayed ossification of fetal
vertebral centra and bllobed thoracic centra, which was reportedly
Indicative of a slight delay In skeletal development and apparently related
to the maternal toxldty, also occurred In offsprings of rats exposed to 590
ppm. Treatment-related embryotoxlc or teratogenlc effects were not observed
1n the rats at any exposure concentration.
There was evidence of slight maternal toxlclty among rabbits exposed to
210 or 590 ppm, as absolute and relative liver weights were Increased 1n
these groups (John et al., 1984). Several cases of external and visceral
malformations (head and facial anomalies, heart defects) occurred among the
exposed groups, but the effects were not dose-related and affected fetuses
did not all show the same malformations. To ascertain whether the low Inci-
dence of malformations was a true effect of treatment, a second Inhalation
study was conducted 1n which groups of 30-32 pregnant rabbits were exposed
to 0, 10, 30, 75 or 590 ppm chlorobenzene (other aspects of the experimental
design were the same as those In the first study). This study did not
reveal any significant Increase or trend for clustering of malformations 1n
0040H -13- 01/19/89
-------
the exposed groups when considered Individually or collectively. Maternal
toxlclty, as In the first study, was evidenced by significantly Increased
liver weights occurring at 210 and 590 ppm. There were no treatment-related
embryotoxlc effects.
In a two-generation reproduction study, groups of 30 male and 30 female
Sprague-Dawley rats (designated as F.) were exposed to chlorobenzene vapor
at concentrations of 0, 50, 150 or 450 ppm for 10 weeks prior to mating and
during mating, gestation and lactation. The progeny of the F_ generation
(designated as F,) was exposed to the same concentration of chlorobenzene
(30 males and 30 females/group) 1 week postweanlng for 11 weeks prior to
mating and through mating, gestation and lactation. No adverse effects on
reproductive performance or fertility were observed In this two-generation
study. The only significant hlstopathologlcal changes observed were hepato-
cellular hypertrophy and renal changes 1n the FQ and F, male rats at 150
and 450 ppm.
3.4. TOXICANT INTERACTIONS
No pertinent data that confirmed the Interaction of chlorobenzene with
other xenoblotlcs could be located In the available literature.
Generalizing that the halogenated benzenes appeared to Increase the activity
of mlcrosomal cytochrome P-450-dependent enzyme systems, the U.S. EPA
(1980a) suggested that exposure to chlorobenzene might be expected to hasten
metabolism of other xenoblotlcs to either more or less toxic metabolites.
Shelton and Weber (1981) Investigated the hepatotoxldty of a mixture of
carbon tetrachlorlde and chlorobenzene (1:38 molar ratio, mixed In corn oil)
1n male CF-1 mice. The dosages used (0.01 mi/g bw) were given by
Intraperltoneal Injection. Although parameters of hepatotoxldity were not
mentioned, the U.S. EPA (1985a) stated that the dose-response did not
deviate from that predicted on the basis of concentration addition.
0040H -14- 01/19/89
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4. CARCINOGENICITY
4.1. HUMAN DATA
No reports that associated chlorobenzene with cancer 1n humans could be
located 1n the available literature.
4.2. BIOASSAYS
The NTP (1985) conducted a study of the cardnogenldty of chlorobenzene
1n F344/N rats and B6C3F1 mice. Based on data from a 13-week dose range-
finding experiment (see Section 3.1.1.), 50 rats/sex were treated by gavage
with 60 or 120 mg/kg, 5 days/week for 103 weeks. Both untreated and
vehicle-treated control groups of 50 rats/sex were maintained.
Throughout the study, body weight of treated and control rats remained
comparable (NTP, 1985). Survival rates were similar until -70 weeks of
treatment, at which time survival In high-dose group males was significantly
reduced. Survival at the end of 2 years was 68, 78, 64 and 52% In untreated
control, vehicle-treated control, low-dose and high-dose males, respec-
tively. Among female rats, 2-year survival data were 74, 58, 60 and 62% 1n
untreated control, vehicle-treated control, low-dose and high-dose groups,
respectively.
In male rats, a significant Increase 1n neoplastlc nodules 1n the liver
was observed 1n the high-dose group (Table 4-1) as determined by both the
Incidental tumor test (p=0.021) and the Cochran-ArmHage test for dose-
related trend (p=0.027). Liver carcinomas 1n male rats were found only 1n
the vehicle-treated group (2/50). Combining the Incidences of neoplastlc
nodules and carcinomas failed to create an overall tumor Incidence that was
statistically significant. There was no evidence of neoplastlc nodule or
liver tumor formation In female rats.
0040H -15- 05/02/88
-------
TABLE 4-1
Statistical Comparisons of Liver Tumors In Male Rats
Treated with Chlorobenzene*
Tumor Type Untreated
Control
NeoplasUc nodule 4/50 (8%)
Incidental tumor test
Cochran-Armltage test
Fisher exact test
Carcinoma 0/50 (0%)
Incidental tumor test
Cochran-Armltage test
Fisher exact test
Neoplastlc nodule or
carcinoma 4/50 (8%)
Incidental tumor test
Cochran-Armltage test
Fisher exact test
Vehicle
Control
2/50 (4%)
p=0.011
p=0.027
NA
2/50 (4%)
p=0.139
p=0.098
NA
4/50 (8%)
p=0.054
p=0.121
NA
60 mg/kg
4/49 (8%)
p=0.290
NA
p=0.329
0/49 (OX)
p=0.283
NA
p=0.253
4/49 (8%)
p=0.570
NA
p=0.631
120 mg/kg
8/49 (16%)
p=0.021
NA
p=0.043
0/49 (0%)
p=0.331
NA
p=0.253
8/49 (16%)
p=0.083
NA
p=0.168
*Source: NTP, 1985
NA = Not applicable
0040H
-16-
08/20/87
-------
Pituitary adenomas 1n the high-dose males and females and endometrlal
stromal polyps 1n the low-dose females occurred at Incidences that were
significantly lower than In the controls.
The cardnogenlclty of chlorobenzene was also tested In B6C3F1 mice
(NTP, 1985). Males were treated with 30 or 60 mg/kg and females were
treated with 60 or 120 mg/kg, 5 days/week for the 2-year (103-week) treat-
ment period. Survival 1n the low- and high-dose males was marginally less
than 1n the controls. The dosages were chosen on the basis of a preliminary
13-week dose range-finding study. It appeared that the doses chosen for the
chronic bloassay, based on the data generated by the 13-week preliminary
study, were too low, and that the maximum tolerated dose had not been
approached (U.S. EPA, 1985a). No tumors occurred with frequencies that
differed significantly from those 1n the control groups.
The U.S. EPA (1985a) stated that the data generated by these studies
were not sufficient to draw conclusions about the cardnogenlclty of chloro-
benzene.
4.3. OTHER RELEVANT DATA
Studies of the mutagenldty of chlorobenzene 1n microorganisms have
yielded mixed results, with positive results observed only In tests with
Saccharomyces cerevlslae (Simmon et al., 1979) and Streptomyces antlblotlcus
(Kesklnova, 1968) (Table 4-2).
In a sex-linked recessive lethal test 1n DrosophUa melanoqaster (Bio-
assay Systems Corp., 1982), male flies were exposed to 36,000 or 128,400 ppm
of chlorobenzene for 1 hour. The exposed flies were mated at 1-3 days (to
sample effects on spermatozoa), 4-5 days (to sample effects on spermatlds)
and 6-7 days (to measure effects on spermatocytes) after exposure. No
evidence of mutagenldty was found 1n 11,543 chromosomes from treated flies
compared with 9430 chromosomes from control flies.
0040H -17- 05/02/88
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A positive response was obtained 1n a test for In vitro Induction of
chromosomal aberrations In Chinese hamster ovary cells (U.S. EPA, 1982b).
Concentrations of 444, 266 and 178 yg/mi were tested In assays that did
not Incorporate a metabolic activating system; concentrations of 493, 296,
197 and 99 yg/mi were assayed with an S-9 activating system. A positive
response was observed 1n the S-9 activated system after a 4-hour exposure
but not after a 2-hour exposure. It 1s concluded 1n U.S. EPA (1985a) that
the negative results may be due to an Insufficient exposure time, and
chlorobenzene 1s clastogenlc 1n Chinese hamster ovary cells.
A negative response was obtained In a forward mutation test In mouse
lymphoma L5178Y cells (Monsanto Company, 1976). A metabolic activating
system was used at concentrations of 0.0001-0.01 yl/ml but not at
0.001-0.1 yl/ml.
4.4. WEIGHT OF EVIDENCE
No evidence of carclnogenlclty associated with exposure to chlorobenzene
In humans was located In the available literature. IARC has not evaluated
the human risk associated with oral or Inhalation exposure to chlorobenzene,
and there are no conclusions about the carclnogenlclty In U.S. EPA (1985a)
as a result of the Inadequate data base. In the NTP (1985) bloassay,
chlorobenzene administration Increased the occurrence of neoplastlc nodules
of the liver In high-dose male F344/N rats, providing evidence of
carclnogenlclty In male rats [as discussed 1n U.S. EPA's Risk Assessment
Forum Report (U.S. EPA, 1986c)]. However, two liver carcinomas were
observed In vehicle-treated rats but none In rats treated with
chlorobenzene, and combining the Incidences of benign neoplastlc nodules and
carcinomas does not result In an overall statistically significant tumor
0040H -19- 06/15/89
-------
Increase. Carcinogenic effects of chlorobenzene were not observed 1n female
F344/N rats or In male or female B6C3F1 mice. Therefore, although the NTP
bloassay provided some, but not clear, animal evidence of cardnogenlcHy,
the overall carcinogenic evidence 1n animals Is judged to be Inadequate.
In conclusion, because of the combination of Inadequate carcinogenic
evidence 1n experimental animals and lack of human evidence, chlorobenzene
Is placed 1n EPA Group D; I.e., not classifiable as to human carclnogenldty
using the we1ght-of-ev1dence classification scheme (U.S. EPA, 1986b).
0040H -20- 05/04/89
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5. REGULATORY STANDARDS AND CRITERIA
A summary of regulatory standards and criteria for chlorobenzene 1s
presented 1n Table 5-1. ACGIH (1986), OSHA (1985) and NIOSH (1982) recom-
mend a TLV-TWA of 75 ppm (350 mg/m3} for occupational exposure to
chlorobenzene. No STEL has been set.
The U.S. EPA (1980a) derived an ambient water quality criterion of 488
vg/8. to protect human health. This criterion Is based on an ADI of
1.008 mg/day; average water consumption of 2 l/day and consumption of fish
and shellfish are also considered.
0040H -21- 04/18/89
-------
TABLE 5-1
Current Regulatory Standards and Criteria for Chlorobenzene
Standard or Criterion
Value
Reference
TLV-TWA
TWA
Ambient water quality criteria:
Freshwater aquatic life
Acute toxldty
Saltwater aquatic life
Acute toxldty
Chronic toxldty
Ambient water quality criterion:
Human life
Organoleptlc
75 ppm (-350 mg/m3)
75 ppm
250
160 yg/l
129
488
20 yg/8.
ACGIH, 1986
NIOSH, 1982
U.S. EPA, 1980a
U.S. EPA, 1980a
U.S., EPA, 1980a
U.S.. EPA, 1980a
U.S.. EPA, 1980a
0040H
-22-
04/18/89
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6. RISK ASSESSMENT
6.1. SUBCHRONIC REFERENCE DOSE (RfD$)
6.1.1. Oral (RfDSQ). NOAELs from subchronlc oral studies Include 14.4
mg/kg/day In rats (Irish, 1963), 50 mg/kg/day In rats (Monsanto Company,
1967b), 89.3 mg/kg/day 1n rats (125 mg/kg, 5 days/week) (NTP, 1985), 12.5
mg/kg/day In rats (Knapp et a!., 1971) and 27.3 mg/kg/day In dogs (Monsanto
Company, 1967a; Knapp et al., 1971). The Irish (1963) study reported a NOEL
of 14.4 mg/kg/day and LOAEL of 144.4 mg/kg/day; however, Intermediate doses
were not evaluated. The Monsanto Company (1967a,b) studies defined a NOAEL
of 50 mg/kg/day and a LOAEL of 100 mg/kg/day for the rat. In contrast, a
NOEL of 27.3 mg/kg/day and a LOAEL of 55 mg/kg/day were defined for the
dog. The observed adverse effects Indicated a higher sensitivity of the dog
to chlorobenzene than the rat. Based on these findings, the highest dog
NOEL of 27.3 mg/kg/day (Monsanto Company, 1967a) was considered appropriate
to derive an RfOSQ. A conversion factor of 5/7 1s used to adjust for
partial weekly exposure (5 days/week) and an uncertainty factor of 100 Is
applied to account for Interspedes extrapolation (10) and to protect
especially sensitive populations (10). Assuming a body weight for man of 70
kg, an RfDso can be calculated as 0.2 mg/kg/day or 14 mg/day for a 70 kg
human.
Immature leukocytes, low blood sugar, conjunctivitis, vomiting and
diarrhea were reported In dogs at 55 mg/kg/day; higher doses caused mortal-
ity and hlstopathologlcal lesions 1n liver and kidneys (Monsanto Company,
1967a). A human MED was calculated by multiplying the dog MED by the cube
root of the ratio of the body weight of dogs (assumed: 12.7 kg) to that of
humans (assumed: 70 kg) and dividing the result by 10, an uncertainty factor
chosen to reflect the unknowns 1n extrapolating from a subchronlc study to
0040H -23- 04/18/89
-------
chronic application. The result, 3.1 mg/kg/day, 1s multiplied by 70 and an
MED of 218 mg/day for a 70 kg man 1s derived. This MED corresponds to an
RV, of 2.0; the effects of vomiting, diarrhea, conjunctivitis and Immature
luekocytes rate an RV of 4. A CS of 8, the product of RV. and RV ,
C 0 C
1s calculated.
6.1.2. Inhalation (RfDSI). NOELs of 85-228 mg/kg/day In rats (Monsanto
Company, 1978; Irish, 1963), 101 mg/kg/day In rabbits (Irish, 1963), 91
mg/kg/day In guinea pigs (Irish, 1963) and 45 mg/kg/day 1n dogs (Monsanto
Company, 1978) were Identified for subchronlc Inhalation exposures (see
Table 3-2). NOAELs of 38 and 126 mg/kg/day, which reflect decreased SGOT
levels, were Identified 1n rabbits (DUley, 1977) (see Table 3-2). In
another experiment by DUley (1977) (see Table 3-2), exposures at 46
mg/kg/day (75 ppm, 7 hours/day, 5 days/week for 120 days) produced small
focal lesions In the adrenal cortex and kidney tubules, congestion of the
liver and kidneys and decreased SGOT In rats; this Intake represents a
LOAEL. Dogs that received 91 mg/kg/day (1.5 mg/i, 6 hours/day, 5
days/week) experienced weight loss and were moribund by 31 days (Monsanto
Company, 1978). The available data Indicate that dogs are more sensitive
than rats or rabbits, but do not provide a NOEL (45 mg/kg/day 1n dogs) or
NOAEL (38 mg/kg/day In rats) that 1s safely below the 46 mg/kg/day LOAEL In
rats. The 46 mg/kg/day rat LOAEL therefore provides the most appropriate
basis for an RfDSj. Assuming a human body weight of 70 kg and using an
uncertainty factor of 1000 to estimate a NOAEL from a LOAEL (10), for
Interspedes extrapolation (10), and to protect unusually sensitive human
subgroups (10), the RfDSI 1s calculated to be 3 mg/day.
The only teratogenlc effects, evidenced by delayed ossification,
occurred In the offspring of rats exposed to 590 ppm chlorobenzene for 6
0040H -24- 04/18/89
-------
hours/day on days 6-15 of gestation (John et al., 1984). Using the
assumptions footnoted In Table 3-2 this exposure provided an Intake of 433
mg/kg/day, which was well above the LOAEL used to derive the RfDrj-
Therefore the RfDSI derived, based on minor hlstologlcal changes In rats
at 46 mg/kg/day, Is appropriate.
6.2. REFERENCE DOSE (RfD)
6.2.1. Oral (RfDQ). No reports of chronic oral exposure of humans to
chlorobenzene were located 1n the available literature. In the only chronic
animal study, reduced survival occurred 1n male mice (marginal reduction)
treated by gavage at doses of 30 or 60 mg/kg, 5 days/week for <103 weeks and
1n male rats that were similarly treated with 120 (but not 60) mg/kg (NTP,
1985). Treatment-related clinical signs of toxldty or decreases 1n body
weight were not observed In either species. The only Indications of
pathologic effects were equivocal evidence of mild hepatocellular necrosis
In low- and high-dose rats of both sexes, and neoplastlc nodules 1n the
livers of high-dose male rats. NTP (1985) concluded that treatment was not
a likely cause of reduced survival 1n the mice, and that the toxlcologlcal
significance of reduced survival 1n the rats 1s unknown. A NOAEL of 60
mg/kg 1s Identified by the chronic studies 1n rats and mice for the
following reasons: survival 1n the male mice was "not adversely affected by
administration of chlorobenzene" at doses of 30 and 60 mg/kg, equivocal mild
hepatocellular necrosis without other effects occurred at 60 mg/kg In rats,
and neoplastlc nodules 1n the liver and reduced survival occurred at 120
mg/kg 1n rats.
The 60 mg/kg NOAEL, which Is equivalent to 42.9 mg/kg/day when adjusted
for partial weekly (5 days/7 days) exposure, 1s most appropriately used to
0040H -25- 04/18/89
-------
support the NOEL of 27.3 mg/kg/day 1n the Monsanto Company (1967a) sub-
chronic oral study with dogs, In which dogs were more sensitive than rats
(see Section 6.1.1.)- Therefore, 1t appears that the NOEL of 27.3 mg/kg/day
1n the 90-day dog study Is the most appropriate basis for an RfD for chronic
oral exposure. Application of an uncertainty factor of 1000, a factor of 10
to estimate a chronic NOAEL from a subchronlc NOAEL, 10 to extrapolate from
dogs to humans, and 10 to protect unusually sensitive Individuals and a
conversion factor of 5/7 to account for partial weekly exposure results In
an RfDQ of 0.02 mg/kg/day or 1.4 mg/day for a 70 kg human. This value was
verified by the U.S. EPA RfD Workgroup on 01/19/89. An AADI of 6 mg/day was
calculated from the 125 mg/kg NOAEL Identified In the NTP prechronlc
bloassays with rats and mice (U.S. EPA, 1985b).
6.2.2. Inhalation (RfD.). No reports of chronic exposure of humans to
chlorobenzene that were satisfactory for risk assessment or studies of
chronic animal exposure could be located In the available literature. The
study by Dllley (1977), which was used to derive the RfDSI of 3 mg/day
(see Section 6.1.2.), can be used to derive an RfD, for Inhalation
exposure. An additional uncertainty factor of 10 to account for derivation
of a chronic RfD, from subchronlc data results In an RfD, of 0.3 mg/day.
This RfD, value was derived for Interim purposes and the Issue of Inhala-
tion RfD for chlorobenzene Is pending discussion by the EPA RfD Workgroup.
6.3. CARCINOGENIC POTENCY (q.,*)
6.3.1. Oral. No reports of cardnogenlclty In humans or animals result-
Ing from oral exposure to chlorobenzene could be located 1n the available
literature. In the only NTP (1985) bloassay In which chlorobenzene was
administered to rats and mice by gavage, the Incidence of neoplastlc nodules
was Increased significantly 1n high-dose males only. Chlorobenzene-related
0040H -26- 04/18/89
-------
carcinogenic effects were not observed 1n female rats or mice of both sexes
1n the NTP bloassay (1985). In addition, liver carcinomas were observed In
vehicle-treated male rats (2/50) but not In chlorobenzene-treated rats.
Overall, the NTP bloassay on chlorobenzene provided some but not clear
evidence of cardnogenldty. Therefore, chlorobenzene Is classified as a
U.S. EPA Group D carcinogen based on Inadequate animal we1ght-of-ev1dence
and the lack of human evidence.
6.3.2. Inhalation. No reports of cardnogenldty 1n humans or animals
that were associated with Inhalation exposure to chlorobenzene could be
located 1n the available literature; hence, no estimation of carcinogenic
potency has been made.
0040H -27- 04/18/89
-------
7. REFERENCES
ACGIH (American Conference of Governmental Industrial Hyglenlsts). 1986.
Documentation of the Threshold Limit Values for Substances 1n Workroom Air,
4th ed. Cincinnati, OH. p. 123.
Bloassay Systems Corp. 1982. DrosophHla sex-linked recessive lethal test
on monochlorobenzene. U.S. EPA, Office of Pesticides and Toxic Substances,
Washington, DC. TSCA Section 8(d) submission. (Cited In U.S. EPA, 1985a)
Branson, D.R. 1978. Predicting the fate of chemicals In the aquatic
environment from laboratory data. ASTM STP 657. American Society for
Testing and Materials, Philadelphia, PA. p. 55-76.
Delchmann, W.B. 1981. Halogenated cyclic hydrocarbons. In.: Toxicology.
Patty's Industrial Hygiene and Toxicology, 3rd ed., Vol. 2B, G.D. Clayton
and E.E. Clayton, Ed. John Wiley and Sons, Inc., NY. p. 3605-3611. (Cited
In U.S. EPA, 1982a)
Dllley, J.V. 1977. Toxic Evaluation of Inhaled Chlorobenzene. NIOSH,
DHEW, Cincinnati, OH. Contract 210-76-0126. (CHed 1n U.S. EPA, 1985a)
Gabor, S. and K. Raucher. 1960. Studlen zur Bestlmmung der zulasslgne
benzol und monochorbenzol grenzkonzentratlonen. J. Hyg. Epldemlol.
M1crob1ol. Immunol. 4: 223-231. (Ger.) (CHed In U.S. EPA, 1985a)
0040H -28- 04/18/89
-------
Glrard, R., F. Tolot, P. Martin and 0. Bourret. 1969. Serious blood
disorders and exposure to chlorine derivatives of benzene (A report of 7
cases). J. Hed. Lyon. 50: 771-773. (Cited 1n U.S. EPA, 1985a)
Hansch, C. and A.J. Leo. 1985. Medchem Project. Issue No. 26. Pomona
College, Claremont, CA.
HolUngsworth, R.L., V.K. Rowe, F. Oyen, H.R. Hoyle and H.C. Spencer. 1956.
Toxldty of paradlchlorobenzene: Determination on experimental animals and
human subjects. AMA Arch. Ind. Health. 14: 138-147. (CHed 1n U.S. EPA,
1980b)
Horvath, A.L. 1982. Halogenated Hydrocarbons: Solub1l1ty-M1sc1b1lHy with
Water. Marcel Dekker, Inc., New York, NY. p. 889.
Irish, D.D. 1963. Halogenated hydrocarbons: II. Cyclic. Iri: Industrial
Hygiene and Toxicology, Vol. II, 2nd ed., F.A. Patty, Ed. Intersdence, NY.
p. 1333-1361. (Cited 1n U.S. EPA, 1980b)
John, J.A., H.C. Hayes, T.R. Hanley, Jr., K.A. Johnson, T.S. Gushow and K.S.
Rao. 1984. Inhalation teratology study on monochlorobenzene In rats and
rabbits. Toxlcol. Appl. Pharmacol. 76(2): 365-373.
Kesklnova, D.V. 1968. The effect of d1methylcyclod1azomethane 1n chloro-
benzene solution on mutagenesls In Actlnomyces antlblotlcus 400. Genetlka.
4(8): 121-125. (CHed 1n U.S. EPA, 1985a)
0040H -29- 04/18/89
-------
Khanln, A.G. 1977. Pathological changes In the general nervous system and
Internal organs of experimental animals after chronic continuous Inhalation
of toxic substances. Chem. Abstr. 74: 97-106. (CHed In U.S. EPA, 1985a)
Knapp, W.K., Jr., W.H. Busey and W. Kundzlns. 1971. Subacute oral toxlclty
of monochlorobenzene 1n dogs and rats. Toxlcol. Appl. Pharmacol. 19: 393.
(Abstr.) (Cited 1n U.S. EPA, 1980a)
Mabey, W.R., J.H. Smith and R.T. Podoll. 1981. Aquatic Fate Process Data
for Organic Priority Pollutants. Monitoring and Data Support Division,
Office of Water Regulations and Standards, Washington, DC. EPA 440/4-81-014.
Merck and Company. 1978. Summary of Monochlorobenzene Bacterial Mutagen
Jest (Ames Test). Office of Pesticides and Toxic Substances, U.S. EPA,
Washington, DC. TSCA Sec 8(d) submission 8DHQ-1078-0302. (Cited 1n U.S.
EPA, 1985a)
Monsanto Company. 1967a. 13-Week oral administration -- dogs, monochloro-
benzene. Submitted by Hazleton Laboratories. U.S. EPA, OPTS, Washington,
DC. TSCA Sec 8(d) submission 8DHQ-1078-0202(2). (CHed In U.S. EPA, 1985a)
Monsanto Company. 1967b. 3-Month subacute oral study of monochlorobenzene
In rats. Submitted by Hazleton Laboratories.U.S. EPA, Washington, DC.
TSCA Sec 8(d) submission 8DHQ-1078-Q212(3). (CHed In U.S. EPA, 1985a)
0040H -30- 04/18/89
-------
Monsanto Company. 1976. Litton B1onet1cs mutagenlcHy evaluation of
B10-76-.86-CP 5535 (WGK): Monochlorobenzene. Office of Pesticides and Toxic
Substances, U.S. EPA, Washington, DC. TSCA Sec 8(d) submission 8DHQ-1078-
0214(1). (Cited In U.S. EPA, 1985a)
Monsanto Company. 1978. Industrial Bio-Test draft report of 90-day sub-
acute vapor Inhalation toxlclty study with monochlorobenzene In beagle dogs
and albino rats. U.S. EPA, OPTS, Washington, DC. TSCA Sec 8(d) submission
8DHQ-1078-0202(1). (Cited In U.S. EPA, 1985a)
NIOSH (National Institute for Occupational Safety and Health). 1982. The
1982 Registry of Toxic Effects of Chemical Substances, R.L. Lewis and R.L.
Tatken, Ed. Cincinnati, OH. (Cited In U.S. EPA, 1985a)
NLM (National Library of Medicine). 1987. National Library of Medicine
Hazardous Substance Data Bank Record No. 55, Computer Printout.
NTP (National Toxicology Program). 1982. Environmental Mutagen Test
Development Program, Research Triangle Park, NC. (Cited In NTP, 1985)
NTP (National Toxicology Program). 1985. Toxicology and cardnogenesls
studies of chlorobenzene (CAS No. 108-99-7) In F344/N rats and B6C3F1 mice
(gavage studies). NTP-TR-261. NIH Publ. 86-2517. NTIS PB86-144714.
OSHA (Occupational Safety and Health Administration). 1985. OSHA Occupa-
tional Standards — Permissible Exposure Limits. Code of Federal Regula-
tions. 29CFR1910.1000.
0040H -31- 04/18/89
-------
Plslaru, V. 1960. Modlflcarl cronaxlmetrlce In Intoxlcatla cronlca cu
benzen s1 monochlorobenzen. Iglena. 9: 127-135. (Cited In U.S. EPA, 1985a)
Prasad, I. 1970. Mutagenlc effects of the herbicide 3' ,4'-d1chloroprop1o-
an1!1de and Its degradation products. Can. J. Mlcroblol. 16: 369-372.
(Cited 1n U.S. EPA, 1985a)
Reich, H. 1934. Puran (Monochlorobenzol)-Verg1ftung bel elnem zweljahrlgen
K1nde. Verglftungsfalle. 5: 193-194. (Ger.) (Cited In U.S. EPA, 1985a)
Rosenbaum, N.D., R.S. Block, S.N. Kremneva, S.L. Glnzburg and I.V.
Pozhar1sk11. 1947. The use of chlorobenzene as a solvent from the point of
view of Industrial hygiene. G1g. SanH. 12(1): 21-24. (Cited In U.S. EPA,
1985a)
Sabljlc, A. 1984. Predictions of the nature and strength of soil sorptlon
of organic pollutants by molecular topology. J. Agrlc. Food Chem. 32:
243-246.
Shelton, D.W. and L.J. Weber. 1981. Quantification of the joint effects of
mixtures of hepatotoxlc agents: Evaluation of a threshold model 1n mice.
Environ. Res. 26: 33-41. (Cited 1n U.S. EPA, 1985a)
Simmon, V.F., E.S Rlcclo and M.V. Pelrce. 1979. in vitro microbiological
genotoxldty assays of chlorobenzene, m-dlchlorobenzene, o-dlchlorobenzene
and p-dlchlorobenzene. Contract No. 68-02-2947. U.S. EPA, ORD, Washington,
DC. (Cited In U.S. EPA, 1985a)
0040H -32- 04/18/89
-------
Singh, H.B., L.J. Salas, A.3. Smith and H. Sh1gl1sh1. 1981. Measurements
of some potentially hazardous organic chemicals In urban environments.
Atmos. Environ. 15: 601-612.
Tarkhova, L.P. 1965. Maximum permissible concentration of chlorobenzene 1n
the atmosphere. Gig. Sanlt. 30: 8. (Cited 1n U.S. EPA, 1985a)
U.S. EPA. 1980a. Ambient Water Quality Criteria for Chlorinated Benzenes.
Prepared by the Office of Health and Environmental Assessment, Environmental
Criteria and Assessment Office, Cincinnati, OH for the Office of Water Regu-
lations and Standards, Washington, DC. EPA 440/5-80-028. NTIS PB 81-117392.
U.S. EPA. 1980b. Guidelines and Methodology Used 1n the Preparation of
Health Effects Assessment Chapters of the Consent Decree Water Quality
Criteria. Federal Register. 45: 79347-79357.
U.S. EPA. 1982a. Hazard Profile for Chlorobenzene. Prepared by the Office
of Health and Environmental Assessment, Environmental Criteria and
Assessment Office, Cincinnati, OH for the Office of Solid Waste, Washington,
DC. EPA 600/8-84-015F. NTIS PB 85-15033.
U.S. EPA. 1982b. Effects of Monochlorobenzene on the jm vitro Induction of
Chromosomal Aberrations In Chinese Hamster Ovary Cells. Prepared for U.S.
EPA by Bloassay Systems Corp. (Cited 1n U.S. EPA, 1985a)
0040H -33- 04/18/89
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U.S. EPA. 1984. Methodology and Guidelines for Reportable Quantity Deter-
minations Based on Chronic Toxldty Data. Prepared by the Office of Health
and Environmental Assessment, Environmental Criteria and Assessment Office,
Cincinnati, OH for the Office of Solid Waste and Emergency Response, Wash-
ington, DC.
U.S. EPA. 1985a. Health Assessment Document for Chlorinated Benzenes.
Office of Health and Environmental Assessment, Environmental Criteria and
Assessment Office, Cincinnati, OH. EPA 600/8-84-015F. NTIS PB 85-150332.
U.S. EPA. 1985b. Drinking Water Criteria Document for Chlorobenzene.
Office of Drinking Water, Washington, DC. Public Comment Draft. NTIS
PB86-117769.
U.S. EPA. 1986a. Reference Values for Risk Assessment. Prepared by the
Office of Health and Environmental Assessment, Environmental Criteria and
Assessment Office, Cincinnati, OH for the Office of Solid Waste, Washington,
DC.
U.S. EPA. 1986b. Guidelines for Carcinogen Risk Assessment. Federal
Register. 51(185): 33992-34003.
U.S. EPA. 1986c. Prollferatlve Hepatocellular Lesions of the Rat: Review
and Future Use In Risk Assessment. Risk Assessment Forum, Washington, DC.
EPA/625/3-86/011.
0040H -34- 05/04/89
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Varshavskaya, S.P. 1967. Comparative toxlcologlcal characteristics of
chlorobenzene and dlchlorobenzene (ortho- and para-lsomers) In relation to
the sanitary protection of water bodies. Hyg. SanH. 33(10): 17-23. (Rus.
trans.) (Cited In U.S. EPA, 1980a)
Velth, 6.D., D.L. DeFoe and B.V. Bergstedt. 1979. Measuring and estimating
the bloconcentratlon factor of chemicals 1n fish. J. F1sh Res. Board Can.
36: 1040-1048.
Williams, R.T. 1959. The Metabolism of Halogenated Aromatic Hydrocarbons.
Detoxlcatlon of Mechanisms, 2nd ed. John Wiley and Sons, Inc., NY. p. 237.
(Cited In U.S. EPA, 1985a)
Wilson, J.T., C.G. Enfleld, W.J. Dunlap, R.L. Cosby, D.A. Foster and L.B.
Baskln. 1981. Transport and fate of selected organic pollutants 1n a sandy
soil. J. Environ. Qua"! • 10: 501-506.
Zoeteman, B.C.J., K. Harmsen, J.B.H.J. Llnders, C.F.H. Morra and W. Slooff.
1980. Persistent organic pollutants 1n river water and groundwater of The
Netherlands. Chemosphere. 9: 231-249.
0040H -35- 05/04/89
-------
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