Toxicological
Profile
for
1,2-DIPHENYLHYDRAZINE
U.S. DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Agency for Toxic Substances and Disease Registry
TP-90-11
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TOXICOLOGICAL PROFILE FOR
1,2-DIPHENYLHYDRAZINE
Prepared by:
Syracuse Research Corporation
Under Subcontract to:
Clement Associates, Inc.
Under Contract No. 205-88-0608
Prepared for:
Agency for Toxic Substances and Disease Registry
U.S. Public Health Service
December 1990
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ii
DISCLAIMER
The use of company or product name(s) is for identification only and
does not imply endorsement by the Agency for Toxic Substances and Disease
Registry.
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iii
FOREWORD
The Superfund Amendments and Reauthorization Act (SARA) of 1986
(Public Law 99-499) extended and amended the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA or Superfund).
This public law directed the Agency for Toxic Substances and Disease
Registry (ATSDR) to prepare toxicological profiles for hazardous
substances which are most commonly found at facilities on the CERCLA
National Priorities List and which pose the most significant potential
threat to human health, as determined by ATSDR and the Environmental
Protection Agency (EPA). The lists of the 250 most significant hazardous
substances were published in the Federal Register on April 17, 1987, on
October 20, 1988, on October 26, 1989, and on October 17, 1990.
Section 104(i)(3) of CERCLA, as amended, directs the Administrator of
ATSDR to prepare a toxicological profile for each substance on the list.
Each profile must include the following content:
(A) An examination, summary, and interpretation of available
toxicological information and epidemiological evaluations on the
hazardous substance in order to ascertain the levels of significant
human exposure for the substance and the associated acute, subacute,
and chronic health effects,
(B) A determination of whether adequate information on the health
effects of each substance is available or in the process of
development to determine levels of exposure which present a
significant risk to human health of acute, subacute, and chronic
health effects, and
(C) Where appropriate, an identification of toxicological testing
needed to identify the types or levels of exposure that may present
significant risk of adverse health effects in humans.
This toxicological profile is prepared in accordance with guidelines
developed by ATSDR and EPA. The original guidelines were published in the
Federal Register on April 17, 1987. Each profile will be revised and
republished as necessary, but no less often than every three years, as
required by CERCLA, as amended.
The ATSDR toxicological profile is intended to characterize succinctly
the toxicological and adverse health effects information for the hazardous
substance being described. Each profile identifies and reviews the key
literature (that has been peer-reviewed) that describes a hazardous
substance's toxicological properties. Other pertinent literature is also
presented but described in less detail than the key studies. The profile
is not intended to be an exhaustive document; however, more comprehensive
sources of specialty information are referenced.
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iv
Foreword
Each toxicological profile begins with a public health statement,
which describes in nontechnical language a substance's relevant
toxicological properties. Following the public health statement is
information concerning significant health effects associated with exposure
to the substance. The adequacy of information to determine a substance's
health effects is described. Data needs that are of significance to
protection of public health will be identified by ATSDR, the National
Toxicology Program (NTP) of the Public Health Service, and EPA. The focus
of the profiles is on health and toxicological information; therefore, we
have included this information in the "beginning of the document.
The principal audiences for the toxicological profiles are health
professionals at the federal, state, and local levels, interested private
sector organizations and groups, and members of the public.
This profile reflects our assessment of all relevant toxicological
testing and information that has been peer reviewed. It has been reviewed
by scientists from ATSDR, the Centers for Disease Control, the NTP, and
other federal agencies. It-has also been reviewed by a panel of
nongovernment peer reviewers and is being made available for public
review. Final responsibility for the contents and views expressed in this
toxicological profile resides with ATSDR.
Ui i.
Administrator
Agency for Toxic Substances and
Disease Registry
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V
CONTENTS
FOREWORD iii
LIST OF FIGURES ix
LIST OF TABLES xi
1. PUBLIC HEALTH STATEMENT 1
1.1 WHAT IS 1, 2-DIPHENYLHYDRAZINE? 1
1.2 HOW MIGHT I BE EXPOSED TO 1,2-DIPHENYLHYDRAZINE? 1
1.3 HOW CAN 1,2-DIPHENYLHYDRAZINE ENTER AND LEAVE MY BODY? 2
1.4 HOW CAN 1,2-DIPHENYLHYDRAZINE AFFECT MY HEALTH? 2
1.5 WHAT LEVELS OF EXPOSURE HAVE RESULTED IN HARMFUL HEALTH
EFFECTS? 3
1.6 IS THERE A MEDICAL TEST TO DETERMINE WHETHER I HAVE BEEN
EXPOSED TO 1,2-DIPHENYLHYDRAZINE? 3
1.7 WHAT RECOMMENDATIONS HAS THE FEDERAL GOVERNMENT MADE TO
PROTECT HUMAN HEALTH? 3
1.8 WHERE CAN I GET MORE INFORMATION? 3
2. HEALTH EFFECTS 9
2.1 INTRODUCTION 9
2.2 DISCUSSION OF HEALTH EFFECTS BY ROUTE OF EXPOSURE 9
2.2.1 Inhalation Exposure 10
2.2.1.1 Death 10
2.2.1.2 Systemic Effects 10
2.2.1.3 Immunological Effects 10
2.2.1.4 Neurological Effects 10
2.2.1.5 Developmental Effects 10
2.2.1.6 Reproductive Effects 10
2.2.1.7 Genotoxic Effects 10
2.2.1.8 Cancer 10
2.2.2 Oral Exposure 10
2.2.2.1 Death 10
2.2.2.2 Systemic Effects 15
2.2.2.3 Immunological Effects 18
2.2.2.4 Neurological Effects 18
2.2.2.5 Developmental Effects 18
2.2.2.6 Reproductive Effects 18
2.2.2.7 Genotoxic Effects 18
2.2.2.8 Cancer 19
2.2.3 Dermal Exposure 19
2.2.3.1 Death 19
2.2.3.2 Systemic Effects 19
2.2.3.3 Immunological Effects 20
2.2.3.4 Neurological Effects 20
2.2.3.5 Developmental Effects 20
2.2.3.6 Reproductive Effects 20
2.2.3.7 Genotoxic Effects 20
2.2.3.8 Cancer 20
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2.3 TOXICOKINETICS 20
2.3.1 Absorption 20
2.3.1.1 Inhalation Exposure ... 20
2.3.1.2 Oral Exposure 20
2.3.1.3 Dermal Exposure 21
2.3.2 Distribution 21
2.3.2.1 Inhalation Exposure 21
2.3.2.2 Oral Exposure 21
2.3.2.3 Dermal Exposure 21
2.3.3 Metabolism 21
2.3.4 Excretion 23
2.3.4.1 Inhalation Exposure 2 3
2.3.4.2 Oral Exposure 2 3
2.3.4.3 Dermal Exposure 23
2.4 RELEVANCE TO PUBLIC HEALTH 23
2.5 BIOMARKERS OF EXPOSURE AND EFFECT 28
2.5.1 Biomarkers Used to Identify or Quantify Exposure
to 1,2-Diphenylhydrazine 29
2.5.2 Biomarkers Used to Characterize Effects Caused
by 1, 2-Diphenylhydrazine 29
2.6 INTERACTIONS WITH OTHER CHEMICALS 29
2.7 POPULATIONS THAT ARE UNUSUALLY SUSCEPTIBLE 30
2.8 ADEQUACY OF THE DATABASE 30
2.8.1 Existing Information on Health Effects of
1, 2-Diphenylhydrazine 30
2.8.2 Identification of Data Needs 32
2.8.3 On-going Studies 35
3. CHEMICAL AND PHYSICAL INFORMATION 37
3.1 CHEMICAL IDENTITY 37
3.2 PHYSICAL AND CHEMICAL PROPERTIES 37
4. PRODUCTION, IMPORT, USE, AND DISPOSAL 41
4.1 PRODUCTION. - 41
4.2 IMPORT. 41
4.3 USE 41
4.4 DISPOSAL. . - 42
5. POTENTIAL FOR HUMAN EXPOSURE . 43
5.1 OVERVIEW. . • 43
5.2 RELEASES TO THE ENVIRONMENT 43
5.2.1 Air. . • 43
5.2.2 Water- • 43
5.2.3 Soil • ¦ 43
5.3 ENVIRONMENTAL FATE. . . . 45
5.3.1 Transp°rt a^d Partitioning 45
5 3.2 Transf°rniation and Degradation .45
5.3.2.1 f7ir • • • • ; : . . 45
5.3.2-2 Water 45
5.3.2-3 Soil. *
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5.4 LEVELS MONITORED OR ESTIMATED IN THE ENVIRONMENT 46
5.4.1 Air 47
5.4.2 Water 47
5.4.3 Soil 48
5.4.4 Other Media 48
5.5 GENERAL POPULATION AND OCCUPATIONAL EXPOSURE 48
5.6 POPULATIONS WITH POTENTIALLY HIGH EXPOSURE 49
5.7 ADEQUACY OF THE DATABASE 49
5.7.1 Identification of Data Needs 49
5.7.2 On-Going Studies 51
6. ANALYTICAL METHODS 53
6.1 BIOLOGICAL MATERIALS 53
6.2 ENVIRONMENTAL SAMPLES 53
6.3 ADEQUACY OF THE DATABASE 55
6.3.1 Identification of Data Needs 55
6.3.2 On-going Studies 56
7. REGULATIONS AND ADVISORIES 57
8. REFERENCES 59
9. GLOSSARY 67
APPENDIX 71
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ix
LIST OF FIGURES
2-1. Levels of Significant Exposure to 1,2-Diphenylhydrazine -
Oral 14
2-2. Metabolic Scheme of 1, 2-Diphenylhydrazine 22
2-3. Existing Information on Health Effects of 1,2-Diphenylhydrazine. . 31
5-1. Frequency of Sites with 1,2-Diphenylhydrazine Contamination. ... 44
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xi
LIST OF TABLES
1-1. Human Health Effects from Breathing 1,2-Diphenylhydrazine 4
1-2. Animal Health Effects from Breathing 1,2-Diphenylhydrazine .... 5
1-3. Human Health Effects from Eating or Drinking
1, 2-Diphenylhydrazine 6
1-4. Animal Health Effects from Eating or Drinking
1, 2-Diphenylhydrazine 7
2-1. Levels of Significant Exposure to 1,2-Diphenylhydrazine - Oral . . 12
2-2. Genotoxicity of 1,2-Diphenylhydrazine - In Vitro 26
2-3. Genotoxicity of 1, 2-Diphenylhydrazine - In Vivo 27
3-1. Chemical Identity of 1,2-Diphenylhydrazine 38
3-2. Physical and Chemical Properties of 1,2-Diphenylhydrazine 39
7-1. Regulations and Guidelines Applicable to 1,2-Diphenylhydrazine . . 58
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1. PUBLIC HEALTH STATEMENT
This Statement was prepared to give you information about
1,2-diphenylhydrazine and to emphasize the human health effects that may
result from exposure to it. The Environmental Protection Agency (EPA) has
identified 1177 sites on its National Priorities List (NPL). 1,2-Diphenyl-
hydrazine has been found at 7 of these sites. However, we do not know how
many of 1177 NPL sites have been evaluated for 1,2-diphenylhydrazine. As
EPA evaluates more sites, the number of sites at which 1,2-diphenylhydrazine
is found may change. The information is important for you because
1,2-diphenylhydrazine may cause harmful health effects and because these
sites are potential are actual sources of human exposure to
1,2-diphenylhydrazine.
When a chemical is released from a large area, such as an industrial
plant, or from a container, such as a drum or bottle, it enters the
environment as a chemical emission. This emission, which is also called a
release, does not always lead to exposure. You can be exposed to a chemical
only when you come into contact with the chemical. You may be exposed to it
in the environment by breathing, eating, or drinking substances containing
the chemical or from skin contact with it.
If you are exposed to a hazardous substance such as 1,2-diphenyl-
hydrazine, several factors will determine whether harmful health effects
will occur and what the type and severity of those health effects will be.
These factors include the dose (how much), the duration (how long), the
route or pathway by which you are exposed (breathing, eating, drinking, or
skin contact), the other chemicals to which you are exposed, and your
individual characteristics such as age, sex, nutritional status, family
traits, life style, and state of health.
1.1 WHAT IS 1,2-DIPHENYLHYDRAZINE?
1,2-Diphenylhydrazine is a white solid. It dissolves only slightly in
water and does not change into a gas unless it is heated to very high
temperatures. It sticks to soil and can be carried into the air along with
windblown dust. Once in water or exposed to air it is changed into other
chemicals within minutes. These chemicals include the toxic chemicals
azobenzene and benzidine. More information about these two chemicals can be
found in the ATSDR Toxicological Profile on Benzidine or by contacting the
Agency for Toxic Substances and Disease Registry (see Section 1.8).
1,2-diphenylhydrazitie is used to make fabric dyes in other countries,
and to make certain medicines. There are no other major manmade or natural
sources of 1,2-diphenylhydrazine. More information on these subjects can be
found in Chapters 3, 4, and 5.
1.2 HOW MIGHT I BE EXPOSED TO 1,2-DIPHENYLHYDRAZINE?
1,2-Diphenylhydrazine does not dissolve in water easily and reacts
quickly when present in water. Therefore, it is extremely unlikely that you
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1. PUBLIC HEALTH STATEMENT
would be exposed to it by drinking water. Also, 1,2-diphcnylhydrazine does
not change to a gas at normal outside temperatures. Therefore, it is
extremely unlikely that you would be exposed to it by breathing air even if
you live near a hazardous waste site. Because 1,2-diphenylhydrazine may
stick to soil, it is possible that you could breathe in dust coated with
1,2-diphenylhydrazine if you entered a hazardous waste site in which it had
been recently spilled on the ground. It is also possible that children
playing at this hazardous waste site could be exposed by eating dirt or
smearing dirt on their skin. It would have to be a site in which the
1,2-diphenylhydrazine was recently spilled on the ground, since once exposed
to air, 1,2-diphenylhydrazine changes into other substances within minutes.
You also could be exposed to 1,2 -diphenylhydrazine if you work in an
industry in which it is used. For example, while working, you could be
exposed to dust containing 1,2-diphenylhydrazine when it is moved from one
place to another. It has not been found in food or in air or natural soils.
If 1,2-diphenylhydrazine exists at all in lakes or streams, it is probably
at levels that are less than 1 part 1,2-diphenylhydrazine in 1,000,000 parts
water (ppm). More information on how you could be exposed to
1,2-diphenylhydrazine can be found in Chapter 5.
1.3 HOW CAN 1,2-DIPHENYLHYDRAZINE ENTER AND LEAVE MY BODY?
If you were to breathe in dust coated with 1,2-diphenylhydrazine you
would probably breathe out most of it within a few minutes; however, some of
it might enter your body. Also, if you were to eat dust; or dirt coated with
1,2-diphenylhydrazine, some of it might enter your body. However, we do not
know how much or how long it would take for the 1,2 -diphenylhydrazine that
you breathe in or eat to enter your body. It is not known if
1,2-diphenylhydrazine would enter your body if you were to spill it on your
skin or if your were to get dirt coated with it on your skin. Some, maybe
most of 1,2-diphenylhydrazine that enters your body leaves your body in the
urine. It is not known how long it takes for 1,2-diphenylhydrazine to leave
the body in the urine. Additional information on how 1,2-diphenylhydrazine
can enter and leave your body is presented in Chapter 2.
1.4 HOW CAN 1,2-DIPHENYLHYDRAZINE AFFECT MY HEALTH?
It is not known if 1,2-diphenylhydrazine would affect your health if
you were to breathe it in or eat it. The health effects of
1,2-diphenylhydrazine in humans have not been studied. Animals die if they
swallow large amounts of 1,2-diphenylhydrazine, and develop liver disease if
they eat small amounts of 1,2-diphenylhydrazine for more than a year.
Therefore, it is possible that if you were to eat large amounts of
1,2-diphenylhydrazine for a long time you might experience liver damage or
die. It is not known whether 1,2-diphenylhydrazine would harm you if you
were to spill it on your skin. It is not known if 1,2-diphenylhydrazine
causes birth defects or affects fertility. It is not known if
1,2-diphenylhydrazine causes cancer in humans; however, it has been shown to
cause cancer in rats and mice that have eaten it in food for most of their
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1. PUBLIC HEALTH STATEMENT
lifetime. Additional information on the health effects of 1,2-diphenyl-
hydrazine is presented in Chapter 2.
1.5 WHAT LEVELS OF EXPOSURE HAVE RESULTED IN HARMFUL HEALTH EFFECTS?
Tables 1-1, 1-2, 1-3, and 1-4 show how little we know about the levels
of 1,2-diphenylhydrazine that might affect your health. As is shown in
Table 1-4, animals that ate food containing 1,2-diphenylhydrazine for a long
time developed lung inflammation, stomach damage, and liver damage, and some
died. Although the levels of exposure that cause harmful effects in humans
are not known, as discussed in Section 1.2, 1,2-diphenylhydrazine is not
likely to be found in food, and you are not even likely to be exposed to
levels of concern if you live near a hazardous waste site. Additional
information on levels of exposure associated with effects can be found in
Chapter 2.
1.6 IS THERE A MEDICAL TEST TO DETERMINE WHETHER I HAVE BEEN EXPOSED TO
1,2-DIPHENYLHYDRAZINE?
There is no test to determine if you have been exposed to
1,2-diphenylhydrazine. More information about tests for exposure and
effects can be found in Chapters 2 and 6.
1.7 WHAT RECOMMENDATIONS HAS THE FEDERAL GOVERNMENT MADE TO PROTECT HUMAN
HEALTH?
A guideline to protect human health, by limiting exposure to
1,2 -diphenylhydrazine in water, has been issued by the federal government.
The U.S. Environmental Protection Agency (EPA) has made recommendations to
limit the concentration of 1,2-diphenylhydrazine in natural waters, such as
lakes and streams. The EPA has developed regulations to limit the release
of 1,2-diphenylhydrazine by industries. Any release of 1 pound or more of
1,2-diphenylhydrazine must be reported to EPA.
1.8 WHERE CAN I GET MORE INFORMATION?
If you have any more questions or concerns not covered here, please
contact your State Health or Environmental Department or:
Agency for Toxic Substances and Disease Registry
Division of Toxicology
1600 Clifton Road, E-29
Atlanta, Georgia 30333
This agency can also give you information on the location of the
nearest occupational and environmental health clinics. Such clinics
specialize in the recognizing, evaluating, and treating illnesses that
result from exposure to hazardous substances.
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1. PUBLIC HEALTH STATEMENT
TABLE 1-1. Human Health Effects fron Breathing 1,2-Diphenylhydrazine*
Short-term Exposure
(less than or equal to 14 days)
Levels
in Air
Length of ExDosure
Description of Effects
The health effects resulting
from short-term exposure
of humans to air con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
Long-term Exposure
(greater than 14
days)
Levels
in Air
Length of Exposure
Description of Effects
The health effects resulting
from long-term exposure
of humans to air con-
taining specific levels of
1,2 -diphenylhydrazine are
not known.
*See Section 1.2 for a discussion of exposures encountered in daily
life.
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1. PUBLIC HEALTH STATEMENT
TABLE 1-2. Animal Health Effects from Breathing 1,2-Diphenylhydrazine
Short-term Exposure
(less than or equal to 14 days)
Levels in Air Lenpth of Exposure Description of Effects
The health effects resulting
from short-term exposure
of animals to air con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
Long-term Exposure
(greater than 14 days)
Levels in Air Length of Exposure Description of Effects
The health effects resulting
from long-term exposure
of animals to air con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
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1. PUBLIC HEALTH STATEMENT
TABLE 1-3. Human Health Effects from Eating or Drinking
1,2-Diphenylhydrazine*
Short-term Exposure
(less than or equal to 14 days)
Leve1s
in
Food
Jpnpfh of Exoosure Description of Effects
The health effects resulting
from short-term exposure
of humans to food con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
Levels
in
Water
The health effects resulting
from short-term exposure
of humans to water con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
Long-term Exposure
(greater than 14 days)
in
Food
length of Exposure Description of Effects
The health effects resulting
from long-term exposure of
humans to food containing
specific levels of 1,2-
diphenylhydrazine are not
known.
Levels
in
Water
The health effects resulting
from long-term exposure
of humans to water con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
*See Section 1.2 for a discussion of exposures encountered in daily
life.
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1. PUBLIC HEALTH STATEMENT
TABLE 1-4. Animal Health Effects from Eating or Drinking
1,2-Diphenylhydraz ine
Short-term Exposure
(less than or equal to 14 days)
Levels in Food Length of Exposure Description of Effects
The health effects resulting
from short-terra exposure
of animals to food con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
Levels in Water The health effects resulting
from short-term exposure
of animals to water con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
Long-term Exposure
(greater than 14 days)
Levels in Food (ppm) Length of Exposure Description of Effects
40
78
weeks
Inflammation of lungs in
rats.
100
78
weeks
Death and liver damage in
rats.
300
78
weeks
Stomach damage in rats.
400
78
weeks
Liver damage and death in
mice.
Levels in Water The health effects resulting
from long-term exposure
of animals to water con-
taining specific levels of
1,2-diphenylhydrazine are
not known.
*These effects are listed at the lowest level at which they were first
observed. They may also be seen at higher levels.
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2. HEALTH EFFECTS
2.1 INTRODUCTION
This chapter contains descriptions and evaluations of studies and
interpretation of data on the health effects associated with exposure to
1,2-diphenylhydrazine. Its purpose is to present levels of significant
exposure for 1,2-diphenylhydrazine based on toxicological studies,
epidemiological investigations, and environmental exposure data. This
information is presented to provide public health officials, physicians,
toxicologists, and other interested individuals and groups with (1) an
overall perspective of the toxicology of 1,2-diphenylhydrazine and (2) a
depiction of significant exposure levels associated with various adverse
health effects.
2.2 DISCUSSION OF HEALTH EFFECTS BY ROUTE OF EXPOSURE
To help public health professionals address the needs of persons
living or working near hazardous waste sites, the data in this section are
organized first by route of exposure -- inhalation, oral, and dermal -- and
then by health effect -- death, systemic, immunological, neurological,
developmental, reproductive, genotoxic, and carcinogenic effects. These
data are discussed in terms of three exposure periods - - acute,
intermediate, and chronic.
Levels of significant exposure for each exposure route and duration
(for which data exist) are presented in tables and illustrated in figures.
The points in the figures showing no-observed-adverse-effect levels (NOAELs)
or lowest-observed-adverse-effect levels (LOAELs) reflect the actual doses
(levels of exposure) used in the studies. LOAELs have been classified into
"less serious" or "serious" effects. These distinctions are intended to
help the users of the document identify the levels of exposure at which
adverse health effects start to appear, determine whether or not the
intensity of the effects varies with dose and/or duration, and place into
perspective the possible significance of these effects to human health.
The significance of the exposure levels shown on the tables and graphs
may differ depending on the user's perspective. For example, physicians
concerned with the interpretation of clinical findings in exposed persons or
with the identification of persons with the potential to develop such
disease may be interested in levels of exposure associated with "serious"
effects. Public health officials and project managers concerned with
response actions at Superfund sites may want information on levels of
exposure associated with mbre subtle effects in humans or animals (LOAEL) or
exposure levels below which no adverse effects (NOAEL) have been observed.
Estimates of levels posing minimal risk to humans (minimal risk levels,
MRLs) are of interest to health professionals and citizens alike.
For certain chemicals, levels of exposure associated with carcinogenic
effects may be indicated in the figures. These levels reflect the actual
doses associated with the tumor incidences reported in the studies cited.
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2. HEALTH EFFECTS
Because cancer effects could occur at lower exposure levels, the figures
also show estimated excess risks, ranging from a risk of one in 10t000 to
one in 10,000,000 (10"^ to 10"7), as developed by EPA.
Estimates of exposure levels posing minimal risk to humans (MRLs) have
been made, where data were believed reliable, for the most sensitive
noncancer end point for each exposure duration. MRLs include adjustments to
reflect human variability and, where appropriate, the uncertainty of
extrapolating from laboratory animal data to humans. Although methods have
been established to derive these levels (Barnes et al. 1987; EPA 1989),
uncertainties are associated with the techniques. Furthermore, ATSDR
acknowledges additional uncertainties inherent in the application of these
procedures to derive less than lifetime MRLs. As an example, acute
inhalation MRLs may not be protective for health effects that are delayed in
development or are acquired following repeated acute insults, such as
hypersensitivity reactions, asthma, or chronic bronchitis. As these kinds
of health effects data become available and methods to assess levels of
significant human exposure improve, these MRLs will be revised.
2.2.1 Inhalation Exposure
No studies were located regarding the following health effects in
humans or animals after inhalation exposure to 1, 2-diphenylhydrazirie:
2.2.1.1 Death
2.2.1.2 Systemic Effects
2.2.1.3 Immunological Effects
2.2.1.4 Neurological Effects
2.2.1.5 Developmental Effects
2.2.1.6 Reproductive Effects
2.2.1.7 Genotoxic Effects
2.2.1.8 Cancer
2.2.2 Oral Exposure
2.2.2.1 Death
No studies were located regarding lethality in humans following oral
exposure to 1,2-diphenylhydrazine. Limited information is available
regarding the lethality of orally-administered 1,2-diphenylhydrazine in
animals. This consists of an incompletely documented acute LD5q Qf
959 mg/kg in rats (Marhold et al. 1968), an unreliable acute lethal dose of
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2. HEALTH EFFECTS
1213 mg/kg/day in mice (Schafer and Bowles 1985), lethal doses for
intermediate duration exposure (4 weeks) of 54 mg/kg/day in rats and 390
mg/kg/day in mice (NTP 1983), and nonlethal and lethal doses for chronic
exposure in rats (2 and 5 mg/kg/day, respectively) and mice (10 and 52
mg/kg/day, respectively) (NTP 1983). The animal lethality data are
discussed below and summarized in Table 2-1.
A single-dose LD50 of 959 mg/kg was determined for rats treated by
gavage with 1,2-diphenylhydrazine in water suspension (Marhold et al. 1968).
Apparently, this value was determined using conventional methodology but the
duration of observation was not reported and it was not indicated if
treatment with undegraded compound was assured. Degradation could be an
issue because 1,2-diphenylhydrazine degrades rapidly in water (Chapter 5).
The cause(s) of mortality in the rats was not reported. The 959 mg/kg LD50
is recorded in Table 2-1 and plotted in Figure 2-1.
In another study, the average amount of 1,2-diphenylhydrazine consumed
by wild deer mice over a 3-day period without killing more than 50% of the
mice was determined to be 1213 mg/kg/day (Schafer and Bowles 1985). The
validity of this finding is uncertain; however, as the dose was estimated
from consumption of seeds treated with only one concentration of chemical,
only five mice were treated, and the actual number of deaths was not
reported. Because of these limitations, the 1213 mg/kg/day dose is not a
reliable effect level for lethality due to acute duration exposure.
Small groups (five) of rats or mice of each sex were administered
various concentrations of 1,2-diphenylhydrazine in the diet for 4 weeks,
followed by 2 weeks without treatment (NCI 1978). Estimated doses ranged
from 3.5-210 mg/kg/day (eight dose levels) in male rats and 0.04-2600
mg/kg/day (nine dose levels) in female rats. Deaths occurred in 2 of 5 male
rats at 54 mg/kg/day and in all rats of both sexes at higher doses.
Although small numbers of rats were tested at each dose, it can be assumed
that the mortality at 54 mg/kg/day was related to treatment because of death
at higher doses. The 54 mg/kg/day dose, therefore, is a LOAEL value for
lethality in rats due to intermediate duration exposure (Table 2-1, Figure
2-1). In mice, estimated doses ranged from 9.1-550 mg/kg/day (eight dose
levels) in males and 0.39-6700 mg/kg/day (nine dose levels) in females.
Deaths occurred in 1 of 5 male mice at 390 mg/kg/day, 2 of 5 male mice at
550 mg/kg/day, 4 of 5 male mice at 950 mg/kg/day, and in all female mice at
6700 mg/kg/day. Using the reasoning used for the rat LOAEL, the 390
mg/kg/day dose can be considered a LOAEL for lethality in mice for
intermediate duration of exposure (Table 2-1, Figure 2-1). Because of
uncertainty related to the small size of the groups, the doses below the rat
and mouse LOAELs are not reliable NOAELs for lethality. The cause(s) of the
mortality in these studies was not indicated.
Rats and mice were fed diets that contained 1,2-diphenylhydrazine for
78 weeks, followed by 28-30 weeks (rats) or 17-18 weeks (mice) without
treatment (NCI 1978). Estimated doses for the rats were 4 and 15 mg/kg/day
-------
TABLE 2-1. Levels of Significant Exposure to 1,2-Oiphenylhy*lrazine - Oral
Figure
Key Species
Route
Exposure
Frequency/
Duration Effect
NQAEL
(mgAg/d)
Less Serious
(m/kg/d)
10AEL (Effect)
Serious
(mg/kg/d)
Reference
ACUTE EXPOSURE
Death
1 Rat
(G)
INTERMEDIATE EXPOSURE
Death
2 Rat (F)
3 House (F)
Systemic
4 Rat (F)
Rat
Mouse
(F)
8 Mouse (F)
1 d
4 wk
4 wk
288 d
4 wk
4 wk
CHRONIC EXPOSURE
Death
7 Rat (F) 78 uk
78 wk
Other
Other
Gastro
Other
19
2600
6700
to
959 (LD50)
54
390
390 (intestinal
hemorrhage)
5 (increased
mortality)
52b (increased
mortality)
Marhold et at.
1968
NCI 1978
NCI 1978
Marhold et al,
1968
NCI 1978
NCI 1978
NCI 1978
NCI 1978
SC
>
SC
m
~n
-------
TABLE 2-1 (Continued)
Exposure
F i gure Frequency/
Key Species Route Duration Effect
NOAEL
(mg/kg/d)
LOAEL (Effect)
Less Serious
(mg/kg/d)
Serious
(mg/kg/d)
Reference
Systemic
9 Rat (F) 78 wk
10 Mouse (F)
12 House (F)
78 wk
Cancer
11 Rat (F) 78 wk
78 wk
Resp
Gastro
Hepatic
Other
Other
Hepatic
Resp
Gastro
5
4
5
10
10
52
52
2C (interstitial
inflammation of
lung)
15 (hyperkeratosis,
acanthosis)
5a (fatty
degeneration)
15 (decreased weight
gain)
52 (decreased body
weight)
52 (coagulative necrosis)
4 (hepatocellular
carcinoma)
52 (hepatocellular
carcinoma)
NCI 1978
NCI 1978
NCI 1978
NCI 1978
ec
>
r1
H
EC
M
T)
w
o
H
un
^Converted to an equivalent concentration of 100 ppm in food for presentation in Table 1-4.
Converted to an equivalent concentration of 400 ppm in food for presentation in Table 1-4.
^Converted to an equivalent concentration of 40 ppm in food for presentation in Table 1-4.
Converted to an equivalent concentration of 300 ppm in food for presentation in Table 1-4.
d = day; (F) = feed; (G) = gavage; Gastro = gastrointestinal; Resp = respiratory; wk = week.
-------
ACUTE INTERMEDIATE
(«14 Days) (15-364 Days)
CHRONIC
(> 365 Days)
(mgfcgMay)
n
x
w
o
H
ty>
Key
r Rat
¦
1050
m Mouse
•
LOAEL V* serious effects (animals)
c»
LOAEL for less serious elects (animals)
o
NOAEL (animals)
~
CEL-Canoer EWed Level
Tb® number rwxl to ci
ech point corresponds 1o entries In Table 2-1.
FIGURE 2-1. Levels of Significant Exposure to 1,2-Diphenylhydrazine-
Oral
-------
15
2. HEALTH EFFECTS
in males, and 2 and 5 rag/kg/day in females. Mortality was increased
significantly only in the high-dose female rats, indicating that 5 mg/kg/day
is a LOAEL for decreased survival due to chronic exposure (Table 2-1, Figure
2-1). These data suggest that female rats are more sensitive than male
rats. Because females appear to be the more sensitive sex and it is not
known if 4 mg/kg/day (the NOAEL in males that is below the 5 mg/kg/day LOAEL
in females) is lethal in females, the 2 mg/kg/day dose in females is the
most reliable NOAEL for lethality in this species. Estimated doses for the
mice were 10 and 52 mg/kg/day in males and 5.2 and 52 mg/kg/day in females.
Mortality was increased significantly in both the high-dose male and female
mice, indicating that the 52 mg/kg/day dose is the LOAEL and 10 mg/kg/day is
the highest NOAEL for lethality in mice due to chronic exposure (Table 2-1,
Figure 2-1). The cause(s) of the mortality in the rats or mice was not
indicated.
2.2.2.2 Systemic Effects
No studies were located regarding cardiovascular, hematological
musculoskeletal, renal, or dermal/ocular systemic effects in humans or
animals following oral exposure to 1,2-diphenylhydrazine.
Respiratory Effects. No studies were located regarding respiratory
effects of 1,2-diphenylhydrazine in humans. One animal study, discussed
below, indicates that chronic oral administration of 1,2-diphenylhydrazine
produced interstitial inflammation of the lungs in rats (NCI 1978) .
Evaluation of the incidence data for nonneoplastic lesions in the NCI
(1978) chronic oral study shows that there were statistically increased
incidences of interstitial inflammation in the lungs of male rats. These
rats were treated with 1,2-diphenylhydrazine in the diet at doses of 4 or 15
mg/kg/day for 78 weeks. Increased incidences of this lesion were also
observed in female rats treated similarly with a dose of 2 mg/kg/day, but
not in mice treated similarly with doses of 5.2 mg/kg/day (females), 10
mg/kg/day (males), or 52 mg/kg/day (males and females). The highest NOAEL
value in mice and the LOAEL in rats for respiratory effects due to chronic
exposure are recorded in Table 2-1 and plotted in Figure 2-1.
Gastrointestinal Effects. No studies were located regarding
gastrointestinal effects of 1,2-diphenylhydrazine in humans. As discussed
below, gastrointestinal effects were observed in an intermediate duration
study with mice (intestinal hemorrhage) (NCI 1978) and a chronic study with
rats (stomach hyperkeratosis and acanthosis) (NCI 1978).
NCI (1978) concluded from pathological examinations of mice that died
in a 4-week diet study of 1,2-diphenylhydrazine that, "Intestinal hemorrhage
was the single gross abnormality consistently observed in these mice." The
severity of the hemorrhage was not described. As indicated in Section
2.2.2.1, deaths occurred in mice at doses 390 mg/kg/day or more but not 280
mg/kg/day or less. Intestinal hemorrhage was not observed in rats that
-------
16
2. HEALTH EFFECTS
died from similar treatment with doses as high as 2600 mg/kg/day. Based on
these data, the 390 mg/kg/day dose can be considered a LOAEL for
gastrointestinal effects in mice due to intermediate duration exposure
(Table 2-1, Figure 2-1). As histological examinations were not conducted on
any of the animals, reliable NOAELs for gastrointestinal effects due to
intermediate exposure in either species cannot be identified.
Evaluation of the incidence data for nonneoplastic lesions in the NCI
(1978) chronic oral study shows that there were statistically increased
incidences of stomach hyperkeratosis and acanthosis in the high dose male
rats. These rats were treated with 1,2-diphenylhydrazine in the diet at a
dose of 15 mg/kg/day for 78 weeks. Increased incidences of these lesions
were not observed in male rats treated with 4 mg/kg/day, female rats
treated similarly with doses of 2 or 5 mg/kg/day, or mice treated similarly
with doses of 5.2 mg/kg/day (females), 10 mg/kg/day (males), or 52
mg/kg/day (males or females). Due to the prevalence of the hyperkeratosis
(21% versus 4% in controls) and acanthosis (36X versus 4% in controls),
appearance of these lesions due to dietary treatment (they are more commonly
associated with gavage treatment), and occurrence of gross intestinal
hemorrhage in mice treated with higher doses of 1,2-diphenylhydrazine in the
4-week NCI (1978) study, the effects are considered to be adverse. The 15
mg/kg/day dose therefore is a LOAEL for gastrointestinal effects in rats
due to chronic duration exposure (Table 2-1, Figure 2-1). The highest doses
not producing gastrointestinal histologic alterations in the rats (5
mg/kg/day) and mice (52 mg/kg/day) are NOAELs for gastrointestinal effects
due to chronic exposure (Table 2-1, Figure 2-1),
Hepatic Effects. No studies were located regarding hepatic effects of
1,2-diphenylhydrazine in humans. Chronic oral administration of
1,2-diphenylhydrazine produced degenerative alterations in the liver of rats
(fatty metamorphosis) and mice (coagulative necrosis) (NCI 1978),
Evaluation of the incidence data for nonneoplastic lesions in the NCI
(1978) chronic oral study shows that there was a statistically increased
incidence of fatty metamorphosis of the liver in the high-dose male rats
(20% versus 0% in controls). These rats were treated with
1,2-diphenylhydrazine in the diet at a dose of 15 mg/kg/day for 78 weeks.
Fatty metamorphosis was also observed in 20% of the high dose (5 mg/kg/day)
female rats. Although the increased incidence in the high dose female rats
was not statistically significant when compared with the incidence (12%) in
the matched control group, the incidence was statistically significant when
compared with the incidence (4%) in the control group for the low dose group
of females. Female mice treated similarly with 52 mg/kg/day had a
statistically increased incidence of coagulative necrosis of the liver (13%
versus 0% in controls). High incidences of focal necrosis were seen in low
dose female rats, the high dose control male and female mice, the low dose
treated male and female mice, the high dose treated male mice. The
incidence in the low dose female rats was significantly increased above the
matching control group, but not above the control group for the high dose
-------
17
2. HEALTH EFFECTS
treated group. A similar effect was not seen in the high dose female rats.
The high incidence of focal necrosis in the high dose control groups makes
meaningful interpretation of the toxicological significance of this
particular lesion difficult. Nevertheless, because of the severity and
prevalence of the liver lesions taken together and the fact that hepatic
neoplasms were observed in this study, the liver is a major target organ of
1,2-diphenylhydrazine in both species. The highest NOAEL value and all
reliable LOAEL values for hepatic effects in both species for chronic
exposure are recorded in Table 2-1 and plotted in Figure 2-1.
Other Systemic Effects. No studies were located regarding other
systemic effects of 1,2-diphenylhydrazine in humans. Decreased body weight
gain and/or weight loss was observed in chronic oral studies with rats and
mice (NCI 1978). As discussed below, these effects may be a consequence of
other toxic effects or cancer.
Initial and final body weights were not significantly different in rats
treated with 19 mg/kg/day in the diet for 288 days (Marhold et al. 1968).
Other endpoints of systemic toxicity were not reported in this study. Body
weights were not depressed consistently in rats and mice treated with
1,2-diphenylhydrazine in the diet at doses as high as 2600 mg/kg/day (rats)
or 6700 mg/kg/day (mice) for A weeks, followed by 2 weeks without treatment
(NCI 1978). These NOAELs for rats and mice are presented in Table 2-1 and
Figure 2-1 as other systemic effects for intermediate duration exposure.
Male rats treated with 1,2-diphenylhydrazine in the diet at a dose of
15 mg/kg/day for 78 weeks had approximately 10-15% decreased body weight
gain (NCI 1978). NCI/NTP usually considers effects on body weight of this
magnitude to be significant. Treatment-related effects on body weight were
not apparent in male or female rats treated similarly with doses of 2-5
mg/kg/day. With the exception of respiratory, gastrointestinal, and hepatic
alterations at 15 mg/kg/day (discussed previously), comprehensive
histological examinations of the rats did not show treatment-related
nonneoplastic lesions. Although food consumption data were not reported,
the decreased weight gain is probably secondary to toxic or neoplastic
effects and should be considered an adverse effect. The doses of 15
mg/kg/day and 5 mg/kg/day therefore are the LOAEL and highest NOAEL,
respectively, for other systemic effects in rats due to chronic duration
exposure (Table 2-1, Figure 2-1).
Male and female mice treated with 1,2-diphenylhydrazine in the diet at
a dose of 52 mg/kg/day for'78 weeks had decreased weight gain and subsequent
weight loss (approximately 30% at termination of the study) (NCI 1978).
Treatment-related effects on body weight were not apparent in mice treated
similarly with 5.2 mg/kg/day (females) or 10 mg/kg/day (males). Except for
hepatic alterations at 52 mg/kg/day (discussed previously), comprehensive
histological examinations of the mice showed no treatment-related
nonneoplastic lesions. As body weight loss is an adverse effect, the
52 mg/kg/day dose is a LOAEL for other systemic effects in mice due to
-------
18
2. HEALTH EFFECTS
chronic duration exposure (Table 2-1, Figure 2-1). The highest NOAEL for
other systemic effects in mice is 10 mg/kg/day (Table 2-1, Figure 2-1)
2.2.2.3 Immunological Effects
No studies were located regarding immunological effects in humans or
animals after oral exposure to 1,2-diphenylhydrazine.
2.2.2.4 Neurological Effects
No studies were located regarding neurological effects in humans after
oral exposure to 1,2-diphenylhydrazine.
Clinical signs and histological examinations of the brain were
unremarkable in rats and mice treated with 1,2-dipheny1hydrazine in the diet
at doses of 15 and 52 mg/kg/day, respectively, for 78 weeks (NCI 1978).
These data provide an inadequate basis for evaluating, possible
neurotoxicity, as behavioral or neurological evnlua t. i wis were not conducted
2.2.2.5 Developmental Effects
No studies were located regarding developmental effect.1; in humans or
animals after oral exposure to 1,2-diphenylhydrazine.
2.2.2.6 Reproductive Effects
No studies were located regarding reproductive effects in humans after
oral exposure to 1,2-diphenylhydrazine .
Histological examinations of the seminal vesicle, testes, prostate
uterus, ovaries, and mammary gland were unremarkable in rats and mice
treated with 1,2-diphenylhydrazine in the diet at doses as high as 15 and 52
mg/kg/day, respectively, for 78 weeks (NCI 1978). These data provide an
insufficient basis for evaluating reproductive toxicity, as reproductive
function was not evaluated.
2.2.2.7 Genotoxic Effects
No studies were located regarding genotoxic effects in humans after
oral exposure to 1,2-diphenylhydrazine.
Sex-linked recessive lethal mutations were not produced in Drosophi i
fed ethanol solution containing 50 ppm 1,2-diphenylhydrazine tor 3 days
(Yoon et al. 1985). No oral genotoxicity studies of 1,2-diphenylhydrazine
in mammals were located.
-------
19
2. HEALTH EFFECTS
2.2.2.8 Cancer
No studies were located regarding carcinogenic effects in humans after
oral exposure to 1,2-diphenylhydrazine. As discussed below, chronic oral
administration of 1,2-diphenylhydrazine was carcinogenic in rats and female
mice (NCI 1978).
Treatment-related neoplasms occurred in rats and mice that were
treated with low or high doses of 1,2-diphenylhydrazine in the diet for 78
weeks, followed by untreated observation periods of 28 or 30 weeks (rats)
and 17 or 18 weeks (mice) (NCI 1978) . Male rats had statistically
significant increased incidences of hepatocellular carcinomas or neoplastic
nodules in the liver due to treatment with 4 mg/kg/day and 15 mg/kg/day, and
squamous-cell carcinomas of the Zymbal's gland and adrenal pheochromocytomas
resulted from treatment with 15 mg/kg/day. Incidences of liver neoplastic
nodules and mammary gland adenocarcinomas were increased significantly in
female rats treated with 5 mg/kg/day, but not 2 mg/kg/day. A significantly
increased incidence of hepatocellular carcinoma occurred in female mice
treated with 52 mg/kg/day, but not 5.2 mg/kg/day. Doses of 10.4 or 52
mg/kg/day were not neoplastic for male mice.
Tumors were not observed in male rats treated with 19 mg/kg/day doses
of 1,2-diphenylhydrazine in the diet for life (mean survival time =
288 days) (Marhold et al. 1968). The significance of this finding is
uncertain because the type and scope of pathological examination were not
reported. Pliss (1974) reported increased numbers of tumors of the liver,
Zymbal's gland, mammary gland and other sites in rats that were treated with
1,2-diphenylhydrazine in the diet at an estimated dose of 85 mg/kg/day, 5
days/week for 588 days (Pliss 1974). These findings are inconclusive,
however, because of lack of control data and other report inadequacies.
The lowest Cancer-Effect-Levels (CELs) in the NCI (1978) bioassay are
the doses that caused hepatocellular carcinoma in rats (4 mg/kg/day) and
mice (52 mg/kg/day) (Table 2-1, Figure 2-1). Using the dose - response data
for the hepatocellular carcinoma in rats, EPA (1980, 1988a) derived and
verified an oral slope factor (qj_*) of 8.0 x 10"1 (mg/kg/day)"for
1,2-diphenylhydrazine. Using this slope factor, the doses associated with
upper-bound lifetime cancer risk levels of 10"^ to 10are calculated to
be 1.3 x 10"^ to 1.3 x lO"'' mg/kg/day, respectively (Figure 2-1).
2.2.3 Dermal Exposure
No studies were located regarding the following health effects in
human or animals after dermal exposure to 1,2-diphenylhydrazine.
2.2.3.1 Death
2.2.3.2 Systemic Effects
-------
20
2. HEALTH EFFECTS
2.2.3.3
Immunological Effects
2.2.3.4
Neurological Effects
2.2.3.5
Developmental Effects
2.2.3.6
Reproductive Effects
2.2.3.7
Genotoxic Effects
2.2.3.8
Cancer
No studies were located regarding carcinogenic effects of
1 2-diphenylhydrazine in humans. As discussed below, inconclusive data for
carcinogenicity of dermally-applied 1,2-diphenylhydrazine in mice are
available.
Dermal application of an estimated 1,2-diphenylhydrazine dose of 63
mE/ke/day three times a week for 442 days, caused a 22.2% incidence of
tumors in'mice (Pliss 1974). Tumors occurred in the lung, liver, and other
tissues and the tumor incidence in control mice was 17%. The significance
of these findings cannot be determined, as incidences of specific tumors in
the control group were not reported.
2.3 TOXICOKINETICS
2.3.1 Absorption
2.3.1.1 Inhalation Exposure
No studies were located regarding absorption in humans or animals
after inhalation exposure to 1,2-diphenylhydrazine. Pulmonary absorption of
1 2-diphenylhydrazine by rats is suggested by detection of an unidentified
metabolite in the urine following intratracheal administration of
1 2-diphenylhydrazine in water suspension and dimethyl sulfoxide (DMSO)
(Dutkiewicz and Szymanska 1973). It is not known, however, if any of the
dose was ingested.
2.3.1.2 Oral Exposure
No studies were located regarding absorption in humans after oral
exposure to 1,2-diphenylhydrazine.
Specific information regarding absorption in animals following oral
exposure to 1,2-diphenylhydrazine was not located.^ Gastrointestinal
absorption of 1,2-diphenylhydrazine by rodents is indicated by the
of parent compound and metabolites in the urine folio* n? oral
treatment (Section 2.3.3) and systemic effects in oral carcinogenicity and
toxicity studies (Section 2.2).
-------
21
2. HEALTH EFFECTS
2.3.1.3 Dermal Exposure
No studies were located regarding absorption in humans or animals
after exposure to 1, 2-diphenylhydrazine. The inadequately reported dermal
carcinogenicity study of 1,2-diphenylhydrazine summarized in Section 2.2.3.8
cannot be used to infer dermal absorption of 1,2-diphenylhydrazine because
the effects are inconclusive.
2.3.2 Distribution
2.3.2.1 Inhalation Exposure
No studies were located regarding distribution in humans or animals
after inhalation exposure to 1,2-diphenylhydrazine.
2.3.2.2 Oral Exposure
No studies were located regarding distribution in humans or animals
after oral exposure to 1,2-diphenylhydrazine.
2.3.2.3 Dermal Exposure
No studies were located regarding distribution in humans or animals
after dermal exposure to 1,2-diphenylhydrazine.
2.3.3 Metabolism
Limited information is available on the metabolism of
1,2-diphenylhydrazine. In the only study involving 1,2-diphenylhydrazine as
the parent compound, urine of rats was analyzed for metabolites following
single oral, intraperitoneal, intravenous, and intratracheal doses of
1,2-diphenylhydrazine (Dutkiewicz and Szymanska 1973). Unchanged
1,2-diphenylhydrazine was detected following treatment by all routes, and
aniline and benzidine were identified following the oral and intraperitoneal
treatments. Other metabolites included two unspecified hydroxy derivatives
of benzidine (oral route), 2- and 4- aminophenol (intraperitoneal route),
and unidentified compounds (oral, intravenous, and intratracheal routes).
Amounts of compounds excreted were not quantitated. Two of the known
metabolites, aniline and benzidine, may contribute to the toxicity and/or
carcinogenicity of 1,2-diphenylhydrazine. The validity of the findings of
this study is uncertain, however, as the analytical methodology (thin-layer
chromatography) may have produced degradation products that were identified
as unchanged 1,2-diphenylhydrazine or metabolites (see Section 6.1).
The metabolites identified by Dutkiewicz and Szymanska (1973) are
consistent with a metabolic scheme proposed by Williams (1959) (Figure 2-2),
which is based on data for azobenzene and aniline. As summarized by NRC
(1981), aniline is oxidized by hydroxylation of a ring carbon to form 2- or
-------
22
2. HEALTH EFFECTS
OH
iH^uoW" \
h° ~~0~~ n"n oh
4'fr*r*<*ytiat«rv«r»
^Q-n n -hQ>
V HH
OH
NH,
4-Amnoexnrw
OH
OR
OH
NHAc
OR
4-Amt«mdopri«nol
OH
NHAC
J-ActumiOoptunol
NH
Source: Williams 1959.
FIGURE 2-2. Metabolic Scheme of 1,2-Diphenylhydrazinc
-------
23
2. HEALTH EFFECTS
4-aminophenol or of the nitrogen to form phenylhydroxylamine, and then is
conjugated to glucuronic or sulfuric acid. An oral study of azobenzene
with conventional and germ-free rats (Macholz et al. 1985) showed that
metabolism of 1,2-diphenylhydrazine to aniline resulted from the reductional
and hydrolytic capability of gut flora. In vitro metabolism of
1,2-diphenylhydrazine to aniline by rat intestinal microorganisms has been
demonstrated (Bolton and Griffiths 1978).
Benzidine is formed readily from 1,2-diphenylhydrazine by acid
rearrangement. It has been suggested that benzidine may be produced from
1,2-diphenylhydrazine by acidity in the stomach (IARC 1972).
2.3.4 Excretion
2.3.4.1 Inhalation Exposure
No studies were located regarding excretion in humans or animals after
inhalation exposure to 1,2-diphenylhydrazine. The presence of an
unidentified metabolite in the urine of rats following intratracheal
administration of 1,2-diphenylhydrazine in water and DMSO suspensions
(Dutkiewicz and Szymanska 1973) suggests that urinary excretion could occur
following inhalation exposure.
2.3.4.2 Oral Exposure
No studies were located regarding excretion in humans after oral
exposure to 1,2-diphenylhydrazine. The identification of unchanged
1,2-diphenylhydrazine and metabolites in the urine following oral dosing of
rats with 1,2-diphenylhydrazine (Dutkiewicz and Szymanska 1973) indicates
that some urinary excretion occurs.
2.3.4.3 Dermal Exposure
No studies were located regarding excretion in humans or animals after
dermal exposure to 1,2-diphenylhydrazine.
2.4 RELEVANCE TO PUBLIC HEALTH
Death. Information regarding death in humans following exposure to
1,2-diphenylhydrazine by any route was not found. Some information is
available on lethality of orally-administered 1,2-diphenylhydrazine in
animals. This information, consisting of a gavage LD50 value in rats
(Marhold et al. 1968) and an unreliable 3-day dietary lethal dose in mice
(Schafer and Bowles 1985) , indicates that single or several oral doses of
about 1000 mg/kg/day may be lethal for rodents. Based on these data,
1,2-diphenylhydrazine does not appear to be highly acutely toxic to humans
by the oral route.
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24
2. HEALTH EFFECTS
Intermediate (4-week) and chronic (78-week) duration diet studies with
rats found that 1,2-diphenylhydrazine produced death at doses as low as 54
and 15 me/kg/day, respectively (NCI 1978). These doses are substantially
lower than those associated with acute lethality. These data suggest that
prolonged ingestion of these doses of 1,2-diphenylhydrazine may be lethal
for humans. However, as discussed in the introduction to Section 2 8.2,
prolonged environmental exposure to 1,2-diphenylhydrazine is unlikely.
Svstemic Effects No information regarding systemic effects in humans
following exposure to 1,2-diphenylhydrazine by any route was found. Very
limited information is available for systemic effects of
1,2-diphenylhydrazine in animals.
NCI (1978) observed a variety of nonneoplastic lesions in rats and
rn 1 2-diohenylhydrazine in the diet for 78 weeks, concluding
Taet L compound-related." Evaluation of the incidence
data for'nonneoplastic lesion., however, shows that there »«,
statistically significant increased incidences of lung interstitial
inflammation and liver fatty metamorphosis in treated male and female rats.
stoS hyperkeratosis and acanthosis in treated male rats, and liver
coagulative necrosis in treated female mice Nonneoplastic Uver lesions
hepatocellular carcinomas and/or neoplastic liver nodules inorally^treat.d
tiepatocei _ that the liver is a target of 1,2-diphenylhydrazine
"x!c"y Gross pathological examinations conducted in the 4-week NCI
(1978) diet study showed intestinal hemorrhages m mice that died. A local
rritative effect of 1.2-diphenyhydrazine is suggested by the occurrence of
the stomach hyperkeratosis/acanthosis in rats and intestinal hemorrhage in
mice Since hydrazine and some hydrazine derivatives are hepatotoxic and
local irritants (Reinhardt and Brittelli 1981), it is possible that
-diphenylhydrazine could cause similar effects in humans.
Intravenous injection of an 18.4 mg/kg dose of 1,2-diphenylhydrazine
did not cause methemoglobinemia in rats, although methemoglobin was formed
did not c aniline (Pfordte 1973). Information on
methemoglobinemia in animals following treatment with 1,2-diphenylhydrazine
h other routes was not located. As aniline and other aromatic ammo
^t-;iholites of 1 2-diphenylhydrazine (e.g., aminophenols) are methemoglobin-
emia compounds by either oral or inhalation routes of exposure (Beard and
^1981) it is possible that 1,2-diphenylhydrazine may cause
methemoglobinemia in humans. However, this would occur only if sufficient
aniline were formed rapidly enough to exceed the capacity of methemoglobin
reductase to reduce methemoglobin.
Immunological Effects. No studies were located regarding
immunological effects of 1,2-diphenylhydrazine in humans or animals by any
route of exposure. This lack of data precludes speculation on possible
immunotoxicity of 1,2-diphenylhydrazine in humans.
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25
2. HEALTH EFFECTS
Neurological Effects. No studies were located regarding neurological
effects of 1,2-diphenylhydrazine in humans by any route of exposure. Rats
and mice that were treated with lethal doses of 1,2-diphenylhydrazine in a
chronic (78-week) diet study did not show symptoms of toxicity or
histological alterations in the brain (NCI 1978), but no behavioral or
neurological evaluations were conducted. The insufficiency of these data
precludes making any conclusions regarding neurotoxicity of
1,2-diphenylhydrazine in humans.
Developmental Effects. No studies were located regarding
developmental effects of 1,2-diphenylhydrazine in humans or animals by any
route of exposure. This lack of data precludes speculation on possible
developmental toxicity of 1,2-diphenylhydrazine in humans.
Reproductive Effects. No studies were located regarding reproductive
effects of 1,2-diphenylhydrazine in humans by any route of exposure. Rats
and mice that were treated with lethal doses of 1,2-diphenylhydrazine in a
chronic (78-week) diet study did not show histological alterations in
reproductive organs (NCI 1978), but reproductive function was not evaluated.
The insufficiency of these data precludes making any conclusions regarding
reproductive toxicity of 1,2-diphenylhydrazine in humans.
Genotoxic Effects. No studies were located regarding the genotoxicity
of 1,2-diphenylhydrazine in humans by any route of exposure. A limited
number of assays have been conducted using bacteria, mammalian cell and
whole animal systems. As indicated in Table 2-2, 1,2-diphenylhydrazine was
mutagenic in Salmonella typhimurium. but not in Escherichia coli. and
produced chromosome aberrations and sister chromatid exchanges in Chinese
hamster cells. An exogenous metabolic activation system was necessary for
expression of the aforementioned effects. In in vivo studies (Table 2-3),
1,2-diphenylhydrazine inhibited testicular DNA synthesis in mice when
administered as a single 100 mg/kg intraperitoneal injection, but did not
cause sex-linked recessive lethal mutations in Drosonhila when administered
in the feed or by injection.
Although only limited data are available, the weight of evidence
indicates that 1,2-diphenylhydrazine is genotoxic in animals. In
particular, positive results were obtained in all assays with mammalian
systems. Overall, the available evidence suggests that 1,2-
diphenylhydrazine may cause chromosomal damage or other genotoxic effects in
humans.
Cancer. Information regarding the carcinogenicity of
1,2-diphenylhydrazine in humans by any route of exposure was not located.
In animals, significantly increased incidences of hepatocellular carcinomas,
neoplastic liver nodules, mammary adenocarcinomas, Zymbal's gland carcinomas
and adrenal pheochromocytomas occurred in rats and/or mice treated with
1,2-diphenylhydrazine in the diet for 78 weeks (NCI 1978). Other
carcinogenicity studies of 1,2-diphenylhydrazine, involving diet treatment
-------
TABLE Z-Z. Genot OKI city of 1,2-Diphenylhydrazine In Vitro
Result
Uith Uithout
End Point Species (Test System) Activation Activation Reference
Prokaryotic organisms:
Gene mutation
Eukaryotic organisms:
Chromosome aberrations
Sister chromatid exchange
Salmonella tvoMrouriim/
plate incorporation
S. typhimurium/
plate incorporation
Escherichia coli WP2uvrA
Chinese hamster ovary cells
Chinese hamster ovary cells
(+)
* = positive; (+) = weakly positive; - = negative; ? = inconclusive.
Dunkel et al. 1985
Haworth et al. 1983
Dunkel et al. 1985
Galloway et al. 1987
Galloway et al. 1987
X
M
>
r1
H
a:
m
•n
m
o
H
w
fsj
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27
2. HEALTH EFFECTS
TABLE 2-3. Genotoxicity of 1,2-Diphenylhydrazine In Vivo
End Point
Species (Test System)
Result
Reference
Sex-linked recessive
lethal mutation
Drosophila melanopaster/
feeding
D. melanoeaster/inj ection
Yoon et al.
1985
Yoon et al.
1985
DNA damage
Mouse/inhibition of
testicular DNA synthesis/
intraperitoneal injection
Seiler 1977
negative; + - positive.
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28
2. HEALTH EFFECTS
in rats (Pliss 1974; Marhold et al. 1978), dermal treat mcnt in mice (Pliss
1974), and subcutaneous or intraperitoneal injection in rats and mice
(Spitz et al. 1950; Genin et al. 1975; Pliss 1974; Shabad and Genin 1975;
Kurlyandskiy et al. 1976; Maronpot et al. 1986), are inconclusive due to
inadequate reporting and other limitations. Although i iicoiic 1 us i ve , most of
these studies reported tumors at sites that are generally consistent with
sites of tumors in the NCI (1978) bioassay (e.g., liver, mammary gland,
adrenal gland, and Zymbal's gland).
The NCI (1978) bioassay, which demonstrated carcinogenicity in two
species, provides sufficient evidence of carcinogenicity of
1,2-diphenylhydrazine in animals. Biotransformation products of
1,2-diphenylhydrazine include aniline and benzidine, which are known
carcinogens in animals (both chemicals) and humans (!>env.i dino) (EPA
1988b,c). Based on the animal evidence for carcinogenicity from the NCI
(1978) bioassay and the carcinogenicity of its metabolites,
1,2-diphenylhydrazine is likely to be carcinogenic in humans.
2.5 BIOMARKERS OF EXPOSURE AND EFFECT
Biomarkers are broadly defined as indicators signaling events in
biologic systems or samples. They have been classified as markers of
exposure, markers of effect, and markers of susceptibility (NAS/NRC, 1989).
A biomarker of exposure is a xenobiotic substance or its metabolite(s)
or the product of an interaction between a xenobiotic agent and some target
molecule or cell that is measured within a compartment of an organism
(NAS/NRC 1989). The preferred biomarkers of exposure arc generally the
substance itself or substance-specific metabolites in readily obtainable
body fluid or excreta. However, several factors can confound the use and
interpretation of biomarkers of exposure. The body burden of a substance
may be the result of exposures from more than one source. The substance
being measured may be a metabolite of another xenobiotic (e.g., high urinary
levels of phenol can result from exposure to several different aromatic
compounds). Depending on the properties of the substance (e.g., biologic
half-life) and environmental conditions (e.g., duration and route of
exposure), the substance and all of its metabolites may have left the body
by the time biologic samples can be taken. It may bo difficult to identify
individuals exposed to hazardous substances that are commonly found in body
tissues and fluids (e.g., essential mineral nutrients such as copper, zinc
and selenium). Biomarkers of exposure to 1,2-dlphenylhydrazine are
discussed in Section 2.5.1.
Biomarkers of effect are defined as any measurable biochemical,
physiologic, or other alteration within an organism that, depending on
magnitude, can be recognized as an established or potential health
impairment or disease (NAS/NRC 1989). This definition encompasses
biochemical or cellular signals of tissue dysfunction (e.g., Increased liver
enzyme activity or pathologic changes in female genital epithelial cells),
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29
2. HEALTH EFFECTS
as well as physiologic signs of dysfunction such as increased blood pressure
or decreased lung capacity. Note that these markers are often not substance
specific. They also may not be directly adverse, but can indicate potential
health impairment (e.g., DNA adducts). Biomarkers of effects caused by
1,2 -diphenylhydrazine are discussed in Section 2.5.2.
A biomarker of susceptibility is an indicator of an inherent or
acquired limitation of an organism's ability to respond to the challenge of
exposure to a specific xenobiotic. It can be an intrinsic genetic or other
characteristic or a preexisting disease that results in an increase in
absorbed dose, biologically effective dose, or target tissue response. If
biomarkers of susceptibility exist, they are discussed in Section 2.7,
"POPULATIONS THAT ARE UNUSUALLY SUSCEPTIBLE."
2.5.1 Biomarkers Used to Identify or Quantify Exposure to
1,2-Diphenylhydrazine
No studies were located regarding biomarkers of exposure to 1,2-
diphenylhydrazine. The metabolites of 1,2-diphenylhydrazine were identified
in one study (Dutkiewicz and Szymanska); however, the validity of the
findings is uncertain because of the analytical methodology used (see
Section 2.3.3 Metabolism). No enzymatic changes that could be used as
biomarkers of 1,2-diphenylhydrazine exposure are known.
2.5.2 Biomarkers Used to Characterize Effects Caused by 1,2-
Diphenylhydrazine
No biomarkers of effects were identified for 1,2-diphenylhydrazine
exposure. No specific alterations in the organism that could be recognized
as biomarkers were found, and the most susceptible organs or tissues were
not identified.
2.6 INTERACTIONS WITH OTHER CHEMICALS
A carcinogenicity study was reported in which groups of rats were
given weekly subcutaneous injections of 1,2-diphenylhydrazine (20 mg), or
1,2-diphenylhydrazine (20 mg) concurrently with benzidine sulfate (15 mg)
for life (Genin et al. 1975). Combined incidences of tumors (injection
site, liver, and other sites) were increased and the mean tumor latent
period was decreased in the group with combined 1,2-diphenylhydrazine and
benzidine sulfate exposure.. It is unclear whether these findings provide
evidence for an interaction between 1,2-diphenylhydrazine and benzidine or
additive effects of two carcinogens. The results of this study were also
reported by Shabad and Genin (1975) and Kurlyandskiy et al. (1976).
Concurrent exposure to 1,2-diphenylhydrazine and benzidine could occur
during benzidine production, since 1,2-diphenylhydrazine is used as a
starting material in the production of benzidine, which is a degradation or
metabolic product of 1,2-diphenylhydrazine.
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30
2. HEALTH EFFECTS
2.7 POPULATIONS THAT ARE UNUSUALLY SUSCEPTIBLE
No populations with unusual susceptibility to health effects of
1,2-diphenylhydrazine have been identified. It is possible that people with
chronic liver disease or possibly compromised hepatic function (e.g., very
young or very old people, alcoholics) might be unusually susceptible to
1,2-diphenylhydrazine, because the liver is a target organ of
1,2-diphenylhydrazine in animals.
2.8 ADEQUACY OF THE DATABASE
Section 104(i}(5) of CERCLA directs the Administrator of ATSDR (in
consultation with the Administrator of EPA and agencies and programs of the
Public Health Service) to assess whether adequate information on the health
effects of 1,2-diphenylhydrazine is available, Where adequate information
is not available, ATSDR, in conjunction with the National Toxicology Program
(NTP), is required to assure the initiation of a program of research
designed to determine the health effects (and techniques for developing
methods to determine such health effects) of 1,2-diphenylhydrazine.
The following categories of data needs have been identified by a joint
team of scientists from ATSDR, NTP, and EPA. They are defined as substance-
specific informational needs that, if met would reduce or eliminate the
uncertainties of human health assessment. In the future, the identified
data needs will be evaluated and prioritized, and a substance-specific
research agenda will be proposed.
2.8.1 Existing Information on Health Effects of 1,2-Diphenylhydrazine
The existing data on health effects of inhalation, oral, and dermal
exposure of humans and animals to 1,2-diphenylhydrazine are summarized in
Figure 2-3. The purpose of this figure is to illustrate the existing
information concerning the health effects of 1,2-diphenylhydrazine. Each
dot in the figure indicates that one or more studies provide information
associated with that particular effect. The dot does not imply anything
about the quality of the study or studies. Gaps in this figure should not
be interpreted as "data needs" information.
Information regarding health effects of 1,2-diphenylhydrazine in
humans is not available. Except for one dermal study, health effects of
1,2-diphenylhydrazine in animals have been investigated only in oral
exposure studies. As indicated in Figure 2-3, animal oral data are
available for lethality, systemic effects due to intermediate and chronic
duration exposure, and genotoxicity and cancer. These data indicate that
oral exposure to 1,2-diphenylhydrazine was life-shortening, hepatotoxic,
irritating to the stomach, and carcinogenic to rats and/or mice. Limited
animal data are available for neurologic and reproductive effects due to
oral exposure, and for cancer due to dermal exposure.
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31
2. HEALTH EFFECTS
SYSTEMIC
Inhalation
Oral
Dermal
HUMAN
SYSTEMIC
Inhalation
Oral
Dermal
ANIMAL
Existing Studi«f
FIGURE 2-3. Existing Infornation on Health Effects of
1,2-Diphenylhydrazine
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32
2. HEALTH EFFECTS
2.8.2 Identification of Data Needs
Acute-Duration Exposure. Information is not available on the health
effects of 1,2-diphenylhydrazine resulting from inhalation exposure in
humans or animals. Because 1,2-diphenylhydrazine is a solid with a low
vapor pressure at ambient temperatures, it is highly unlikely that
inhalation exposure to this chemical in the vapor state would occur (Chapter
5). However, the possibility of inhalation exposure to dusts of 1,2-
diphenylhydrazine either free or adsorbed to soil is conceivable.
Therefore, acute studies of inhalation exposure to dusts of 1,2-
diphenylhydrazine could be designed to provide information on possible toxic
effects and exposure levels that cause effects. No studies were located
regarding acute oral exposure in humans. The only pertinent acute exposure
toxicity studies of 1,2-diphenylhydrazine were conducted in rats; these
consist of an oral LD50 assay and methemoglobin determination following
intravenous treatment. Additional acute oral exposure studies could
corroborate the LD50, identify systemic effects, and provide information on
thresholds of effects as well as interspecies differences. However,
although ingestion of 1,2-diphenylhydrazine-contaminated soil from waste
sites is conceivable, extensive oral studies appear to be unwarranted as the
possibility of exposure from ingestion of contaminated soil seems unlikely,
and exposure via drinking water is essentially nonexistent because of the
rapid oxidation of 1,2-diphenylhydrazine in water (Chapter 5). Because of
the lack of dose-effect information, no MRL was derived. Pharmacokinetic
data are insufficient for identification of target organs across routes of
exposure. No studies were located regarding acute dermal exposure in humans
or animals. Acute dermal studies of 1,2-diphenylhydrazine with animals
could provide information on skin and eye irritation, lethality, and other
toxic effects. Dermal studies of 1,2-diphenylhydrazine appear to be most
relevant, as dermal exposure is a likely route of environmental exposure.
As discussed in Chapter 5, dermal exposure via direct chemical contact or
contact with contaminated soil is possible at hazardous waste sites, where
high concentrations of crystalline 1,2-diphenylhydrazine could occur.
Intermediate-Duration Exposure. No information was located regarding
intermediate-duration inhalation exposure to 1,2-diphenylhydrazine in humans
or animals. As discussed for acute-duration exposure, 1,2-diphenylhydrazine
is a solid with a low vapor pressure at ambient temperature, which makes
inhalation exposure to this chemical in the vapor state unlikely. However,
the possibility of inhalation exposure to dusts of 1,2-diphenylhydrazine
either free or adsorbed to soil is conceivable. Therefore, intermediate-
duration studies of inhalation exposure to dusts of 1,2-diphenylhydrazine
could be designed to provide information on possible toxic effects and
exposure levels that cause effects. A limited number of intermediate-
duration oral studies provide information on lethality and/or gross
pathology in rats and mice. Because of the lack of reliable information
about dose-relationship, no MRL was derived. Pharmacokinetic data were
insufficient for identification of target organs across routes of exposure.
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33
2. HEALTH EFFECTS
Additional studies examining histology or other sensitive endpoints could
elucidate systemic effects and thresholds of toxicity. Intermediate-
duration dermal studies examining systemic toxicity in animals could provide
information on whether repeated dermal exposure of humans poses a threat of
toxic effects. This information would be useful for an evaluation of health
risk in populations living near hazardous waste sites that might be
repeatedly exposed to 1,2-diphenylhydrazine-contaminated soil.
Chronic-Duration Exposure and Cancer. No studies were located
regarding chronic inhalation exposure to 1,2-diphenylhydrazine in humans or
animals. As discussed for acute- and intermediate-duration exposure,
1,2-diphenylhydrazine is a solid with a low vapor pressure at ambient
temperature, which makes inhalation exposure this chemical in the vapor
state unlikely. However, the possibility of inhalation exposure to dusts of
1,2-diphenylhydrazine either free or adsorbed to soil is conceivable.
Therefore, chronic-duration studies of inhalation exposure to dusts of
1,2-diphenylhydrazine could be designed to provide information on possible
toxic effects and exposure levels that cause effects. The NCI (1978)
bioassay of 1,2-diphenylhydrazine provides the only sufficient chronic oral
toxicity data for this chemical. This study was not, however, subjected to
the peer review process used for current NTP bioassays, and it inadequately
evaluated nonneoplastic effects. Additional studies would be particularly
useful for corroborating and more fully characterizing 1,2-diphenyl-
hydrazine-induced systemic toxicity. In particular, more studies could
provide information on cause(s) of death due to chronic exposure, and
delineate carcinogenic and noncarcinogenic doses. No studies were located
regarding toxic effects after chronic dermal exposure to 1,2-diphenyl-
hydrazine in humans or animals. Because of the lack of reliable data, no
MRL for chronic exposure was derived, Pharmacokinetic data were
insufficient for identification of target organs across routes of exposure.
More information regarding chronic dermal exposure would be useful for
possible extrapolation of results to humans that may be exposed to
1,2-diphenylhydrazine near hazardous waste sites for a long period of time.
The paucity of systemic toxicity data for this chemical appears to be
related to primary interest in testing for carcinogenicity. Treatment-
related neoplasms developed in rats and mice that were treated with
1,2-diphenylhydrazine in a diet. An inconclusive chronic dermal
carcinogenicity study of 1,2-diphenylhydrazine with mice was available. The
development of neoplasia was reported in the exposed group. The results
from the controls were nothowever, provided. The available data, although
scarce, indicate a possible carcinogenic potential for 1,2-diphenyl-
hydrazine. This finding is supported by some genotoxicity studies.
Additional chronic dermal studies would be useful to further investigate
1,2-diphenylhydrazine carcinogenicity.
Genotoxicity. A limited number of in vitro assays with bacteria and
mammalian cells and an in vivo assay with mice indicate that
1,2-diphenylhydrazine is genotoxic. Replicate assays have not been
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34
2. HEALTH EFFECTS
conducted with the exception of assays with Salmonella. and mutation in
mammalian systems and genotoxicity in human cells have not been evaluated.
Additional studies, particularly involving mammalian systems and providing
information on the potential for heritable mutations, would add to the
database on genotoxicity and validate available information.
Reproductive Toxicity. The unremarkable histology of the reproductive
organs of the rats and mice in the NCI (1978) bioassay provides limited
information on the lack of reproductive toxicity of 1,2-diphenylhydrazine
Multigeneration or continuous breeding studies in animals would provide a
basis for evaluation of potential reproductive effects of
1,2-diphenylhydrazine in humans.
Developmental Toxicity. It is not known whether 1,2-diphenylhydrazine
crosses the placenta, but there is no reason to assume that it (or its
metabolites) would not do so. Developmental studies in mammals would
provide information on possible fetotoxic and teratogenic effects of
1,2-diphenylhydrazine that might be relevant to humans.
Immunotoxicity. No histopathological effects on immunological organs
and tissues of rats and mice were found in the NCI (1978) chronic oral
bioassay of 1,2-diphenylhydrazine. Adequate evaluation of immunotoxic
potential is precluded by a lack of specific immunotoxicity tests of
1,2-diphenylhydrazine. Dermal sensitization tests in animals might provide
information on whether an allergic response to 1,2-diphenylhydrazine is
likely.
Neurotoxicity. No clinical signs of central nervous system toxicity or
histological alterations of nervous system organs and tissues were observed
in rats or mice in the NCI (1978) chronic oral bioassay. Tests for
neurotoxicity in animals may be appropriate if there is clinical evidence of
neurological dysfunction in general oral or dermal toxicity studies of
1,2-diphenylhydraz ine.
Epidemiological and Human Dosimetry Studies. Health effects of
1,2-diphenylhydrazine have not been described in humans. As discussed in
Chapter 5, the potential for environmental exposure to 1,2-diphenylhydrazine
is extremely low. Although dermal exposure to 1,2-diphenylhydrazine could
occur at a contaminated waste site, it is highly unlikely that segments of
the general population will be exposed to 1,2-diphenylhydrazine.
If 1,2-diphenylhydrazine or its metabolites in urine can be correlated
with dermal exposure in humans, it may be possible to monitor humans for
exposure. If toxic effects resulting from dermal exposure to
1,2-diphenylhydrazine are identified in humans, it may then be possible to
correlate urinary levels of 1,2-diphenylhydrazine or a metabolite with
systemic effects.
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35
2. HEALTH EFFECTS
Biomarkers of Exposure and Effect. No biomarkers are known that are
specific for 1,2-diphenylhydrazine exposure. Continued efforts to devise
more sensitive and more specific early biomarkers of disease (especially
cancer) would be valuable.
Absorption, Distribution, Metabolism, Excretion. The general
metabolic pathways of 1,2-diphenylhydrazine are identifiable based on
limited evidence for 1,2-diphenylhydrazine in oral, intratracheal, and
injection experiments with rats (Dutkiewicz and Szymanska 1973), metabolism
data for azobenzene (which is metabolized to 1,2-diphenylhydrazine), and
metabolism data for aniline (an initial metabolite). The relative
contribution of the different pathways is not established. Although oral
absorption of 1,2-diphenylhydrazine and urinary excretion of
1,2-diphenylhydrazine and its metabolites are apparent, there is no
information on the rate and extent of absorption, or excretion, or tissue
distribution following oral exposure. Investigations of the toxicokinetics
of 1,2-diphenylhydrazine following dermal exposure have not been conducted.
Additional studies of absorption, distribution, metabolism, and excretion in
animals by the oral and dermal routes of exposure would provide information
needed for sufficient characterization of the toxicokinetics of
1,2-diphenylhydrazine. Studies addressing differences in metabolism between
oral and dermal routes would be particularly informative, as benzidine may
be formed by acidity in the stomach.
Comparative Toxicokinetics. No data are available to determine if
there are differences in the toxicokinetics of 1,2-diphenylhydrazine among
species. Toxicokinetic studies with different species could help explain
observed differences in toxicity and carcinogenicity between rats and mice,
and help identify the animal species that serves as the best model for
extrapolating results to humans.
2.8.3 On-going Studies
No ongoing studies of 1,2-diphenylhydrazine were identified.
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37
3. CHEMICAL AND PHYSICAL INFORMATION
3.1 CHEMICAL IDENTITY
Data pertaining to the chemical identity of 1,2-diphenylhydrazine
listed in Table 3-1.
3.2 PHYSICAL AND CHEMICAL PROPERTIES
The physical and chemical properties of 1,2-diphenylhydrazine are
presented in Table 3-2.
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38
3. CHEMICAL AND PHYSICAL INFORMATION
TABLE 3-1. Chemical Identity of 1,2-Diphenylhydrazine
Value
Reference
Chemical name
1,2 -Diphenylhydrazine
CAS 1988
Synonyms
Hydrazobenzene
N,N'-diphenylhydrazine
sym-diphenylhydraz ine
CAS 1988; SANSS 1988
Trade names
No data
Chemical formula
c12h12n2
CAS 1988
Chemical structure
fV „ , _/=>.
H H
SANSS 1988
Identification numbers:
CAS Registry
NIOSH RTECS
EPA Hazardous Waste
OHM-TADS
DOT/UN/NA/IMCO Shipping
HSDB
NCI
122-66-7
MW2625000
U109
8100209
No data
2882
C0185A
CAS 1988
HSDB 1983
HSDB 1988
HSDB 1988
HSDB 1988
HSDB 1988
CAS - Chemical Abstracts Services; DOT/UN/NA/IMCO - Department of
Transportation/United Nations/North America/International Maritime Dangerous
Goods Code; EPA - Environmental Protection Agency; HSDB - Hazardous
Substance Data Bank; NCI - National Cancer Institute; NIOSH - National
Institute for Occupational Safety and Health; RTECS - Registry of Toxic
Effects of Chemical Substances; OHM/TADS - Oil and Hazardous
Materials/Technical Assistance data System.
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39
3. CHEMICAL AND PHYSICAL INFORMATION
TABLE 3-2. Physical and Chemical Properties of
1,2-Diphenylhydrazine
Property
Value
Reference
Molecular weight
Color
Physical state
Melting point
Boiling point
Specific gravity, 16/4°C
Odor
Odor threshold
Solubility:
Water at 20°C
Organic solvents
Partition coefficients:
Log octanol/water
Log Koc
Vapor pressure at 25°C
Henry's law constant
Autoignition temperature
Flashpoint, open cup
Flammability limits
Conversion factors
184.24
White
Crystalline solid
123-126°C
309°C
1.158
No data
No data
66.9 mg/L (calculated
using equation 40)
Very soluble in
alcohol; slightly
soluble in benzene
2.94 (experimental)
2.73 (calculated using
equation 4-10)
2.6 x 10
-5
mmHg
9.42 x 10"® atm-m^/mol
(calculated from water
solubility and vapor
pressure)
No data
No data
No data
No data
Ahuja et al. 1988
Dean 1985
Aldrich Catalog 1988
PCGEMS Estimation
Dean 1985
Neely and Blau 1985
Dean 1985
Hansch and Leo 1985
Lyman et al. 1982
Mabey et al. 1981
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41
4. PRODUCTION, IMPORT, USE, AND DISPOSAL
4.1 PRODUCTION
1,2-Diphenylhydrazine is produced in the stepwise reduction of
nitrobenzene by the action of iron or zinc powder in caustic solution (e.g.,
caustic soda, alcoholic alkaline) first to azoxybenzene, then azobenzene,
and finally 1,2-diphenylhydrazine (Sandridge and Staley 1978). A batch
process is used in which a caustic soda solution is added to a heated vessel
charged with nitrobenzene and iron borings. Additions of iron in caustic
soda solution are made to continue the reaction. When the reaction is
complete, separation of the 1,2-diphenylhydrazine from the iron sludge is
accomplished by solvent extraction or by alternative methods, such as
stopping the reaction at the azobenzene step and performing the final
reduction in a zinc-alcoholic alkali solution followed by filtration and
washing of the sodium zincate mass.
No recent information was located regarding production volumes of
1,2-diphenylhydrazine. The U.S. International Trade Commission last
reported production of 1,2-diphenylhydrazine for the 1978 production year
(USITC 1979). In that year, Bofors Lakeway, Muskegon, MI, reportedly
produced and isolated 1,2-diphenylhydrazine, but no volumes were published.
The USITC will not publish production volumes of chemicals for which there
are less than three manufacturers. No producers have been reported by the
USITC since 1978, indicating either that less than 5000 pounds were produced
or that the product was never isolated, but was used directly in the next
reaction step.
4.2 IMPORT
No information concerning the importation or exportation of
1,2-diphenylhydrazine in the United States was located in the literature.
4.3 USE
One of the major uses of 1,2-diphenylhydrazine is as a starting
material in the production of benzidine; however, it is no longer produced
in the United States. 1,2-Diphenylhydrazine rearranges to benzidine upon
treatment with strong acid; benzidine is used by the dye industry for the
production of benzidine-based dyes including many of the Direct dyes (e.g.,
Direct Red 28, Direct Black 4, Direct Blue 2) (Ferber 1978; Lurie 1964).
Fabricolor, the last producer of benzidine based dyes, discontinued
production in 1988 (Personal communication, Alvarez 1989).
1,2-Diphenylhydrazine is used for the production of the drugs
phenylbutazone (trade name Butazolidin, an anti-inflammatory agent) and
sulfinpyrazone (trade name Anturane, a uricosuric agent for the treatment of
gouty arthritis) (Barnhart 1988; Hughes 1981; Kornis 1982). These drugs are
made by the condensation of 1,2-diphenylhydrazine with malonic acid
derivatives to form pyrazolidinedione structures. It is not clear from the
literature if the 1,2-diphenylhydrazine used in the condensation reaction is
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42
4. PRODUCTION, IMPORT, USE, AND DISPOSAL
produced by the manufacturers that use it or if it is purchased by them as
an isolated product.
4.4 DISPOSAL
Very little information was located in the literature concerning the
disposal of 1,2-diphenylhydrazine. Dietrich et al. (1985) reported that wet
air oxidation (heating wastewater under pressure with the addition of an
oxygen-containing gas such as air) would remove 99.88% of the
1,2-diphenylhydrazine in the water (initial concentration, 5000 mg/L). Wet
air oxidation can effectively treat aqueous waste streams that are too
dilute to incinerate, yet too toxic to treat using biological processes.
Results of treatment by wet air oxidation are in keeping with the
observation that 1,2-diphenylhydrazine oxidizes on standing to azobenzene
(Riggin and Howard 1979). Information regarding the amount of
1,2-diphenylhydrazine disposed of in the United States was not located in
the literature.
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43
5. POTENTIAL FOR HUMAN EXPOSURE
5.1 OVERVIEW
1,2-Diphenylhydrazine oxidizes rapidly in the environment under aerobic
conditions, with a half-life in water as short as 15 minutes. This rapid
oxidation coupled with the lack of straightforward sampling methods makes
the assessment of the literature difficult. For example, while a few
monitoring papers report the detection of 1,2-diphenylhydrazine in the
environment, their analytical methodology suggests that it is unlikely that
1,2-diphenylhydrazine would have been detected even if present. In
addition, little information is available to assess the potential for
environmental contamination, making the estimation of environmental releases
difficult. Therefore, not only is the significance of reported
environmental concentrations difficult to interpret, environmental
concentrations are difficult to predict. The fate, transport, and
distribution of 1,2-diphenylhydrazine in the environment are uncertain.
1,2-Diphenylhydrazine has been reported at 7 of 1177 sites in the National
Priority List database (ATSDR 1990); the frequency of these sites within the
United States can be seen in Figure 5-1.
5.2 RELEASES TO THE ENVIRONMENT
5.2.1 Air
No information concerning the release of 1,2-diphenylhydrazine to air
was located in the literature. The vapor pressure of 1,2-diphenylhydrazine
is low (2.6 x 10-5 jnmHg at 256C), indicating that little 1,2-diphenyl-
hydrazine will volatilize from manufacturing and use operations. Dust
generated from the loading and off-loading of 1,2-diphenylhydrazine during
use may cause local atmospheric concentrations. If present in water,
1,2-diphenylhydrazine will probably oxidize to azobenzene before it
volatilizes. Volatilization of 1,2-diphenylhydrazine is not expected to be
an environmentally relevant fate process given the low Henry's Law constant
(9.42 x 10"® atm-nr* mol'^).
5.2.2 Water
No information concerning the release of 1,2-diphenylhydrazine to water
was located in the literature. If discharged to water, detectable
concentrations will probably persist for only a short time, since the half-
life of (100 /ig/L) 1,2-diphenylhydrazine in wastewater is about 15 minutes
(Riggin and Howard 1979, 1982)
5.2.3 Soil
No information concerning the release of 1,2-diphenylhydrazine to soil
was located in the literature. The manufacturing process for
1,2-diphenylhydrazine generates a sludge containing iron and/or zinc
-------
FREQUENCY
333 1 SITE
3 SITES
FIGURE 5-1. FREQUENCY OF NFL SITES WITH 1.2-DIPHENYLHYORAZINE CONTAMINATION
-------
45
5. POTENTIAL FOR HUMAN EXPOSURE
compounds, probably along with small amounts of unextracted
1,2-diphenylhydrazlne. Some of this material may be disposed of in
landfills, but no information is available concerning the
1,2-diphenylhydrazine disposal practices of the manufacturing industry.
5.3 ENVIRONMENTAL FATE
5.3.1 Transport and Partitioning
No information concerning the transport and partitioning of
1,2-diphenylhydrazine in the environment was located in the literature. In
water, 1,2-diphenylhydrazine is not expected to volatilize because of its
rapid oxidation in aerated water (near-surface water) to azobenzene and its
low calculated Henry's Law constant (9.42 x 10"® atm-m^ mol'^) (Lyman et al.
1982). The calculated log Koc (2.76) suggests that 1,2-diphenylhydrazine
may sorb to sediments or suspended particles. This is based on the analysis
of Kenaga (1980), who stated that chemicals with a Koc <100 tend to be
mobile in soil, while those with a Koc >1000 tend to sorb. In soil,
1,2-diphenylhydrazine is not expected to leach to groundwater, based on its
physical and chemical properties (i.e., 1,2-diphenylhydrazine reacts rapidly
under environmental conditions and, based on its Koc, will not rapidly leach
downward in the soil column).
5.3.2 Transformation and Degradation
5.3.2.1 Air
No studies were located regarding the rates or products of reaction of
1,2-diphenylhydrazine in the atmosphere. Based on its behavior in aerated
water, 1,2-diphenylhydrazine may react rapidly in air to form azobenzene as
well as other products resulting from the abstraction of a hydrogen from a
nitrogen by hydroxyl radical. Atkinson (1987) developed a method to
estimate the hydroxyl radical (HO) reaction rate based on structure. Using
this method, an overall reaction rate of 211 x lO"-^ cm"' molecule"^ sec'^
was calculated, which yields a half-life of less than 2 hours for an
atmospheric HO- concentration of 0.5 x 10^ molecules cm'^. This is an
estimated annually averaged concentration for a 24-hour period (Atkinson
1985). 1,2-Diphenylhydrazine also absorbs light above 290 tim (Sadtler
Index, no date) and may be susceptible to photolysis. No information was
found concerning the characteristics of this potential reaction.
5.3.2.2 Water
Very little information was located concerning the fate of
1,2-diphenylhydrazine in water. Riggin and Howard (1979, 1982) reported the
results of a study on the stability of 1,2-diphenylhydrazine in a number of
solvents including distilled water and wastewater. In distilled water at pH
values of 2, 4.7, 7, and 10 and at 4°C or at room temperature, less than 10%
of the initial 10 Mg/L of 1,2-diphenylhydrazine remained in the water after
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46
5. POTENTIAL FOR HUMAN EXPOSURE
1 day. At pH 2, 1,2-diphenylbydrazine degraded to benzidine, while at pH 7
it degraded to an unidentifiable oxidizable product. At pH 10,
1,2-diphenylhydrazine degraded to azobenzene, and at pH 4.7, it degraded
into two unidentifiable products, which were not azobenzene or benzidine.
In secondary municipal sewage effluent, Riggin and Howard (1979, 1982)
reported that 100 ftg/L of 1,2-diphenylhydrazine had a half-life of about 15
minutes in the presence of oxygen, and about 60 minutes when no oxygen was
present. These results suggest that 1,2-diphenylhydrazine is unlikely to
persist in the environment, particularly under aerobic conditions.
Weber and Wolfe (1986, 1987) reported that azobenzene, when incubated
in air with four anaerobic lake sediments containing about 2-4X organic
matter, was reduced to aniline with a reaction half-life of about 2700-5700
minutes, depending on the source and date of specimen collection.
1,2-Diphenylhydrazine was not detected as an intermediate. The authors
postulate a four-electron mechanism involving the intermediate formation of
1,2-diphenylhydrazine.
In reporting the same data, Tabak et al. (1981a,b) and Patterson and
Kodukala (1981) stated that 5 or 10 mg/L of 1,2-diphenylhydrazine was
degraded up to 80% when initially cultured with settled domestic wastewater.
This degradation rate, however, was reduced to 40X in the case of the 10
mg/L concentration, after the third subculture. The authors suggested that
a de-adaptive and toxification process was occurring with
1,2-diphenylhydrazine. It is unclear if the analytical methods used by
these authors would have been able to detect 1,2-diphenylhydrazine if
present. Both dissolved organic carbon and gas chromatography (GC) analyses
were performed on the samples. Considering the sample preparation
procedures, however, the compound detected might not have been
1,2-diphenylhydrazine, but a decomposition product such as azobenzene.
5.3.2.3 Soil
No information concerning the fate of 1,2-diphenylhydrazine in soil was
located in the literature. Based on the fate of 1,2-diphenylhydrazine in
water and sediment, detectable concentrations probably will not persist for
long periods, but this may depend on the initial concentration.
5.4 LEVELS MONITORED OR ESTIMATED IN THE ENVIRONMENT
The rapid oxidation of 1,2-diphenylhydrazine in water to form
azobenzene and other compounds makes its sampling and analysis difficult.
Storing a sample containing 1,2-diphenylhydrazine for even short periods can
result in complete oxidation; in gas chromatography, 1,2-diphenylhydrazine
is oxidized to azobenzene upon injection onto the chromatographic column
(Riggin and Howard 1982). Therefore, unless sampling and analysis are
performed under conditions that will prevent oxidation or unless
concentrations of 1,2-diphenylhydrazine in the sample are very high,
analyses of environmental samples for 1,2-diphenylhydrazine are inaccurate
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47
5. POTENTIAL FOR HUMAN EXPOSURE
(Ahuja et al. 1988; Riggtn and Howard 1979). It is doubtful that the
concentrations measured reflect on the concentrations present in the sample
at the time of collection (i.e., measured concentrations would
underestimate actual concentrations (Riggin and Howard 1982).
5.4.1 Air
No ambient air monitoring for 1,2-diphenylhydrazine was located in the
literature. This may be due to both the rapid oxidation of
1,2-diphenylhydrazine and its low vapor pressure, which limit the amount of
1,2-diphenylhydrazine entering the atmosphere. In addition, no information
was located suggesting that any studies have sought but not found
1,2-diphenylhydraz ine.
5.4.2 Water
Two reported identifications of 1,2-diphenylhydrazine in water samples
were located in the literature. Melton et al. (1981) reported that
1,2-diphenylhydrazine was present in Cincinnati, OH, drinking water (river
water treated by coagulation, sand filtration, and chlorination).
1,2-Diphenylhydrazine was reported at a concentration of 1 ng/L. Since the
sample preparation involved aeration and the original sample was
chlorinated, it is unclear if the detected material was 1,2-diphenyl-
hydrazine. Riggin and Howard (1982) found that, in addition to injection
onto a GC column, either chlorination or aeration of a sample resulted in
total disappearance of 1,2-diphenylhydrazine. Tang et al. (1983) reported
1,2-diphenylhydrazine in coal gasification wastewater at concentrations of
0.149 and 1.786 Mg/L. Sample preparation in this case involved separation
into classes by pH, liquid-liquid extraction, concentration, and gas
chromatography/mass spectroscopy (GC/MS) analysis. No precautions were
taken to reduce the aeration of the sample. Also, the analytical procedure
indicates that no 1,2-diphenylhydrazine would have been able to survive the
conditions of the sample preparation and the detection may be of another
chemical or of 1,2-diphenylhydrazine from another source (e.g.,
decomposition of another compound to 1,2-diphenylhydrazine).
Hall et al. (1985) reported that no 1,2-diphenylhydrazine (less than
1 fj.g/L) was detected in the Nanticoke River near the Chesapeake Bay. The
analytical method involved liquid-liquid extraction, concentration, and
analysis by GC/MS. The Contract Laboratory Program statistical database
(queried April 13, 1987) reported that 1,2-diphenylhydrazine has been
detected in water at 1 of 357 hazardous waste sites at a concentration of
96 ppb (CLPSDB 1987), and has been reported at 7 of 1177 sites in the
National Priority List database (ATSDR 1990). The U.S. EPA Contract
Laboratory Program uses GC methods to analyze the contaminants of interest.
Since 1,2-diphenylhydrazine oxidizes to azobenzene in the GC injector port
and both 1,2-diphenylhydrazine and azobenzene have the same GC retention
time and mass spectra, reports of 1,2-diphenylhydrazine from the Contract
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48
5. POTENTIAL FOR HUMAN EXPOSURE
Laboratory Program may actually represent detections of 1,2-diphenyl-
hydrazine, azobenzene, or both (see Chapter 6 for more details).
5.4.3 Soil
1 2-DiphenylhydrazIne has been identified in soil only at hazardous
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49
5. POTENTIAL FOR HUMAN EXPOSURE
processes used in the production of phenylbutazone and sulfinpyrazone, the
two drugs that use 1,2-diphenylhydrazine as a starting material. A better
understanding of these processes would allow the estimation of worker
exposure potentials. Second, dye manufacturers in the United States no
longer produce benzidine based dyes (the last manufacturer stopped
production in 1988) and the number of workers potentially exposed to
1,2-diphenylhydrazine is now less than at the time of the NOES survey cited
above. Thus, the survey may no longer accurately reflect the number of
workers potentially exposed to 1,2-diphenylhydrazine.
5.6 POPULATIONS WITH POTENTIALLY HIGH EXPOSURE
The only populations with potentially high exposure appear to be
persons receiving phenylbutazone or sulfinpyrazone therapy, those living
near hazardous waste sites, and those in occupations that manufacture or use
1,2-diphenylhydrazine. Very little information concerning these
populations, however, is available to clearly understand the extent of these
potential exposures.
5.7 ADEQUACY OF THE DATABASE
Section 104(i)(5) of CERCLA, directs the Administrator of ATSDR (in
consultation with the Administrator of EPA and agencies and programs of the
Public Health Service) to assess whether adequate information on the health
effects of 1,2-diphenylhydrazine is available. Where adequate information
is not available, ATSDR, in conjunction with the NTP, is required to assure
the initiation of a program of research designed to determine the health
effects (and techniques for developing methods to determine such health
effects) of 1,2-diphenylhydrazine.
The following categories of possible data needs have been identified by
a joint team of scientists from ATSDR, NTP, and EPA. They are defined as
substance-specific informational needs that, if met would reduce or
eliminate the uncertainties of human health assessment. In the future, the
identified data needs will be evaluated and prioritized, and a
substance-specific research agenda will be proposed.
5.7.1 Identification of Data Needs
Physical and Chemical Properties. Physical and chemical properties are
essential for estimating the partitioning of a chemical in the environment.
Data are available for only a few physical and chemical properties of
1,2-diphenylhydrazine, and most of these have limited experimental
descriptions. Therefore, an evaluation of the accuracy of the data is
difficult. Specifically, measured solubility, vapor pressure, Koc, pKa, and
Henry's Law constant at environmentally significant temperatures would help
to remove any doubt concerning the accuracy of the partitioning estimates,
especially in circumstances where 1,2-diphenylhydrazine does not oxidize
rapidly (such as when high concentrations are present). These data form the
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50
5. POTENTIAL FOR HUMAN EXPOSURE
basis of much of the input requirements for environmental models that
predict the behavior of a chemical under specific conditions including
hazardous waste landfills. In addition, the uncertainty in these
measurements can be used to estimate the sensitivity of these properties in
determining the overall fate of 1,2-diphenylhydrazine in the environment.
Production, Use, Release, and Disposal. Production methods for
1,2-diphenylhydrazine are well described in the literature (including the
patent literature); there does not appear to be a need for further
information in this area. Uses of 1,2-diphenylhydrazine are documented but
no recent production figures or detailed descriptions of uses are available.
This information is useful for estimating the potential for environmental
releases from manufacturing and use industries as well as the potential
environmental burden, but it is difficult to obtain in the detail desired
since it is considered confidential business information for those
industries that manufacture 1,2-diphenylhydrazine. Release information is
similar to use information in that it is not obtained easily and can be used
to estimate environmental burdens and potentially exposed populations. A
Toxic Release Inventory will provide some of this information in the
future. Disposal information is useful for determining environmental burden
and potential concentrations where environmental exposures may be high.
Data on different disposal methods for 1,2-diphenylhydrazine are lacking.
According to the Emergency Planning and Community Right to Know Act of 1986
(EPCRTKA), (§313), (Pub. L. 99-499, Title III, §313), industries are
required to submit release information to the EPA. The Toxic Release
Inventory (TRI), which contains release information for 1987, became
available in May of 1989. This database will be updated yearly and should
provide a more reliable estimate of industrial production and emission.
Environmental Fate. Photolysis, photooxidation, and chemical oxidation
studies in air and water are lacking, as are persistence studies in soil
and groundwater. These kinds of studies are important since they address
the fundamental removal mechanisms available to 1,2-diphenylhydrazine in the
environment. In addition, removal mechanisms such as atmospheric
photooxidation may be several orders of magnitude faster than any other
removal mechanism; understanding these reactions is crucial to an
understanding of the fate of 1,2-diphenylhydrazine in the environment.
Biodegradation studies in water may not be important, even though they are
lacking, since 1,2-diphenylhydrazine oxidizes rapidly.
Bioavailability from Environmental Media. No studies were located
regarding the bioavailability of 1,2-diphenylhydrazine from environmental
media, but lack of these data does not necessarily indicate a lack of
bioavailability. As exposure to 1,2-diphenylhydrazine could occur at waste
sites by dermal contact with contaminated soil or by ingestion of
contaminated soil, it would be useful to know if dermal or oral absorption
of 1,2-diphenylhydrazine from environmental media could occur. Information
on dermal absorption of 1,2-diphenylhydrazine from other media is not
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51
5. POTENTIAL FOR HUMAN EXPOSURE
available, but qualitative evidence indicates that 1,2-diphenylhydrazine in
diet or oil media is absorbed from the gastrointestinal tract (Section 2.3).
Food Chain Bioaccumulation. 1,2-Diphenylhydrazine reacts rapidly in
water to form azobenzene and other oxidation products (half-life in
wastewater is 60 minutes). Because of this and based upon the log
octanol/water partition coefficient, no bioaccumulation is expected in any
aquatic organism.
Exposure Levels in Environmental Media. Environmental monitoring data
are not available or are of questionable accuracy for water, soil, and air.
These data would be helpful in determining the ambient concentrations of
1,2-diphenylhydrazine so that exposure estimates for the general population
could be made as well as 1,2-diphenylhydrazine exposure estimates for
terrestrial and aquatic organisms.
Exposure Levels in Humans. The database for exposure levels in humans
is very limited, and it is unclear if an exposed population exists given the
rapid disappearance of 1,2-diphenylhydrazine from the environment. While a
more complete database would be helpful in determining the current exposure
levels and thereby estimating the average daily dose associated with various
scenarios (e.g., living near a hazardous waste site, taking phenylbutazone),
a number of factors limit establishing such a program, including the lack of
appropriate analytical methods.
Exposure Registries. An exposure registry is not available. The
development of such a registry would be a useful reference tool in
assessing exposure levels and frequency. In addition, a registry would
allow an assessment of the variations in exposure concentrations from, for
example, geography, season, regulatory actions, presence of hazardous waste
landfills, or manufacturing and use facilities. These assessments, in
turn, would provide a better understanding of the need for research or data
acquisition based on the current exposure concentrations.
5.7.2 On-Going Studies
No on-going studies were located in the literature.
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53
6. ANALYTICAL METHODS
The purpose of this chapter is to describe the analytical methods that
are available for detecting and/or measuring and monitoring
1,2-diphenylhydrazine in environmental media and in biological samples. The
intent is not to provide an exhaustive list of analytical methods that could
be used to detect and quantify 1,2-diphenylhydrazine. Rather, the intention
is to identify well-established methods that are used as the standard
methods of analysis. Many of the analytical methods used to detect
1,2-diphenylhydrazine in environmental samples are the methods approved by
federal agencies such as EPA and the National Institute for Occupational
Safety and Health (NIOSH). Other methods presented in this chapter are
those that are approved by a trade association such as the Association of
Official Analytical Chemists (AOAC) and the American Public Health
Association (APHA). Additionally, analytical methods are included that
refine previously used methods to obtain lower detection limits, and/or to
improve accuracy and precision.
6.1 BIOLOGICAL MATERIALS
No adequate methods were located for the analysis of
1,2-diphenylhydrazine in biological materials. While thin-layer
chromatography methods have been published, it is not clear if these methods
would be capable of resolving 1,2-diphenylhydrazine from degradation
products that appear rapidly in a sample upon standing (Bolton and Griffiths
1978; Dutkiewicz and Szymanska 1973). These products (some unidentified)
are produced rapidly, and vary depending on the exact conditions (see
below). In addition, none of the metabolites identified (e.g., benzidine,
aniline) are suitable surrogates since they cannot be linked exclusively to
1,2-diphenylhydrazine exposure, but may result from exposure to other
chemicals (and possibly drugs; see above).
6.2 ENVIRONMENTAL SAMPLES
Adequate analytical methods exist for the analysis of
1,2-diphenylhydrazine in environmental samples and are presented below.
However, adequate methods are not available for the sampling, sample
preservation, and sample preparation (extraction) of environmental media.
Neither EPA nor NIOSH have standard methods for analyzing
1,2-diphenylhydrazine in any medium; 1,2-diphenylhydrazine is no longer on
the Target Compound List (TCL) for the Contract Laboratory Program, but is
identified as a semi-volatile compound (EPA 1987a). Riggin and Howard
(1982) reported that 1,2-diphenylhydrazine at 100 pg/L in a municipal sewage
effluent (after secondary treatment) had a time to 50% disappearance of 15
minutes (It degraded completely within 1 hour), but the half-life was
extended to 60 minutes when the wastewater was deaerated. Also, the authors
stated that 1,2-diphenylhydrazine "...analysis in wastewater is virtually
meaningless, since the DPH level determined cannot be directly related to
the DPH in the sample at the time of collection." This limitation may apply
to all environmental media, depending on the exact conditions used to
acquire and store the sample, as well as the sample itself. Even excellent
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54
6. ANALYTICAL METHODS
methods for the analysis of 1,2-diphenylhydrazine will not necessarily yield
concentrations that are representative of the concentrations present in the
medium sampled.
Extracting and concentrating the 1,2-diphenylhydrazine in an
environmental sample may give poor results. Riggin and Howard (1979)
reported that 1,2-diphenylhydrazine extraction from water was
"irreproducible" because of instability when the extract was concentrated.
An extraction efficiency of more than 50% was reported for chloroform
extraction at pH 7. If stored for longer than 1 day, however, the extract
contained less than 10% of the initial 1,2-diphenylhydrazine concentration.
At different pH values, 1,2-diphenylhydrazine degraded into different
products, not all of which were identifiable. This lack of clearly
identifiable degradation products makes identification of a degradation
product as a surrogate for 1,2-diphenylhydrazine difficult. Ahuja et al.
(1988) found that extraction of 1,2-diphenylhydrazine in water containing
TEAM buffer (pH 9.2) showed only 0.9% loss over 30 minutes, although
chromatography was performed within 30 minutes of extraction. Although this
procedure was applied to pharmaceutical analysis, there is no apparent
reason to believe it will not work for environmental analysis.
In addition, Riggin and Howard (1982) reported that analytical
standards of 1,2-diphenylhydrazine prepared in benzene, methylene chloride,
methanol, triethyl amine, acetonitrile, or acetic acid decomposed
completely in 3 days or less. Matsui et al. (1983) reported that
1,2-diphenylhydrazine was oxidized to azobenzene in n-hexane solution at a
rate of about 5%/hr; flushing the n-hexane with nitrogen reduced the
conversion rate to about b% in 2 hours. These authors also found that
nitrogen flushed standards were stable over a 1-hour period, based on the
detector response factors during liquid chromatography. These limitations
should be considered when interpreting analytical results.
Riggin and Howard (1982) reported that 1,2-diphenylhydrazine
"...instantaneously decomposes to azobenzene in the GC injection port." The
authors further stated that:
"It is interesting to note that only one peak resulted from DPH
injection. Occasionally, it was found that a second, later
eluting peak was present ..., but this was not always the case.
This additional component may have been a solution decomposition
product."
Because of this, GC, including GC/MS, does not appear to be an acceptable
analytical tool for the analysis of 1,2-diphenylhydrazine in any sample.
Riggin and Howard (1979, 1982), Matsui et al. (1983), Fabre et al.
(1984), and Ahuja et al. (1988) reported that High Performance Liquid
Chromatography (HPLC) with UV or electrochemical detection is capable of
analyzing 1,2-diphenylhydrazine. Reversed phase chromatographic columns
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55
6. ANALYTICAL METHODS
have been used most often (Ahuja et al. 1988; Fabre et al. 1984; Riggin and
Howard 1979, 1982). Cyano-amino polar bonded phase columns also have been
used (Matsui et al. 1983). Using a reversed phase and UV detection, the
minimum amount detected (on column amounts) is approximately 6-7 ng and the
minimum amount quantifiable is less than 1 /ig (Ahuja et al. 1988; Fabre
et al. 1984; Matsui et al. 1983).
In conclusion, HPLC is preferred over GC for analysis of
1,2-diphenylhydrazine. Sample preservation and extraction methods need
improvement.
6.3 ADEQUACY OF THE DATABASE
Section 104(i)(5) of CERCLA, directs the Administrator of ATSDR (in
consultation with the Administrator of EPA and agencies and programs of the
Public Health Service) to assess whether adequate information on the health
effects of 1,2-diphenylhydrazine is available. Where adequate information
is not available, ATSDR, in conjunction with the NTP, is required to assure
the initiation of a program of research designed to determine the health
effects (and techniques for developing methods to determine such health
effects) of 1,2-diphenylhydrazine.
The following categories of possible data needs have been identified by
a joint team of scientists from ATSDR, NTP, and EPA. They are defined as
substance-specific informational needs that, if met would reduce or
eliminate the uncertainties of human health assessment. In the future, the
identified data needs will be evaluated and prioritized, and a
substance-specific research agenda will be proposed.
6.3.1 Identification of Data Needs
Methods for Determining Biomarkers of Exposure and Effect. No
biomarker that can be associated quantitatively with exposure to 1,2-
diphenylhydrazine has been identified (see Section 2.5). No adequate
methods are available for the analysis of 1,2-diphenylhydrazine in
biological materials. If this information were available, it would allow
both investigators and reviewers to assess the accuracy and uncertainty of
the methods used in toxicological studies. Furthermore, the ready
availability of tested analytical methods, including sample preservation,
would permit a standardized approach to the analysis of biological materials
to assist in measuring human exposure and monitoring effects in humans.
Adequate methods appear to be available for the analysis of 1,2-
diphenylhydrazine metabolites in biological materials. Metabolites include
azobenzene and aniline, both of which appear to be amenable to analysis by
standard methods. 1,2-Diphenylhydrazine and its metabolites, however, have
not been established as a quantitative biomarker of exposure to
1,2 -diphenylhydrazine.
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56
6. ANALYTICAL METHODS
No biomarker that can be associated quantitatively with effect has been
identified (see Section 2.5). Thus, there are no analytical methods for the
determination of biomarkers of effect for 1,2-diphenylhydrazine.
Methods for Determining Parent Compound and Degradation Products in
Environmental Media. While analytical methods appear to be available for
the analysis of 1,2-diphenylhydrazine, no methods were found for the
preservation of 1,2-diphenylhydrazine in ambient air, water, or soil
samples. Such methods would allow the development and analysis of a
monitoring program designed to better assess the concentrations of
1,2-diphenylhydrazine in and around hazardous waste sites.
Methods for Determining Degradation Products in Environmental Media.
Adequate methods are available for the analysis of some
1,2-diphenylhydrazine degradation products in environmental media; however
not all of the major degradation products have been identified. In
addition, the number and nature of degradation products appear to change
depending on conditions (e.g., pH). The development of adequate analytical
methods for identifying degradation products would allow a monitoring
program designed to assess the ambient concentrations of
1,2-diphenylhydrazine degradation products in environmental media to be
established; this would provide information concerning both human and
environmental exposure, since it would allow an estimation of the
concentration of 1,2-diphenylhydrazine in environmental media to be
established prior to degradation. The development of analytical methods
however, must be subsequent to generalized environmental fate studies that
identify the degradation products, A standardized method could then be
developed using spike recoveries from different media to determine the
recovery efficiencies and precision and accuracy of the method.
6.3.2 On-going Studies
No studies were located regarding on-going analytical methods
development for 1,2-diphenylhydrazine.
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57
7. REGULATIONS AND ADVISORIES
National and state regulations and advisories pertinent to human
exposure to 1,2-diphenylhydrazine are summarized in Table 7-1. Guidance
from the World Health Organization (WHO) and the International Agency for
Research on Cancer (IARC) is not available.
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TABLE 7-1. Regulations and Advisories Applicable to 1,2-Diphenyl hydrazine
Agency
Description
Value
Reference
National
Regulations:
a. Nonspecific media:
EPA OERR
EPA OSU
Reportable quantity
Hazardous waste
Groundwater monitoring list
1 pound (statutory)
10 pounds (proposed)
Not applicable
Not applicable
EPA 1987b
40 CFR 117 and 302
40 CFR 261
40 CFR 264
Guidelines:
a. Air:
EPA
Water:
EPA
EPA OURS
c. Other:
EPA
Guidelines:
a. Ai r:
Florida-Tampa
New York
North Dakota
Inhalation unit risk
Drinking water unit risk
Anbient water quality criteria
Ingesting water and organisms
Ingesting organisms only
Carcinogenic classification
Cancer slope factor
State
Acceptable ambient air concentration
2.2 x 10
-4
(/ig/m3)'
1 a
2.2 x 10-5 (/tg/L)
-1 a
4 ng/L, 42 ng/L, 422 ng/La,'>
56 ng/L, 560 ng/L. 5600 ng/La'b
Grotp 82^
8.0 x 10"' (mg/kg/day)"
0.01 mg/m' (8 hr)
3.3 iig/nfi (annual)
BACTd
EPA 1988a
EPA 1988a
EPA 1980
EPA 1980
EPA 1988a
NATICH 1988
NATICH 1988
NATICH 1988
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Ln
oo
b. Water:
Kansas
Minnesota
Drinking water
0.45 pg/L
0.45 iig/l
FSTRAC 1988
FSTRAC 1988
Calculated from cancer slope factor of 8.0 x 10"1 (mg/kg/day)'1.
Criteria corresponding to cancer risk levels of 10"^, 10"^, and 10"5.
Sjroup B2 - Probable hunan carcinogen, based on sufficient evidence from animal studies.
*%est available control technology.
EPA * Environmental Protection Agency; OERR = Office of Emergency and Remedial Response; OURS = Office of Water
Regulations and Standards; OSU = Office of Solid Uaste.
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59
8. REFERENCES
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study of the combined effect of some diphenyl amino derivatives for the
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*Marhold J, Matrka M, Hub H, et al. 1968. The possible complicity of
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*Maronpot RR, Shimkin MB, Witschi HP, et al. 1986. Strain A mouse
pulmonary tumor test results for chemicals previously tested in the National
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*Matsui F, Lovering EG, Curran NM, et al. 1983. Determination of
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67
9. GLOSSARY
Acute Exposure -- Exposure to a chemical for a duration of 14 days or less,
as specified in the Toxicological Profiles.
Adsorption Coefficient (K^,) -- The ratio of the amount of a chemical
adsorbed per unit weight of organic carbon in the soil or sediment to the
concentration of the chemical in solution at equilibrium.
Adsorption Ratio (Kd) -- The amount of a chemical adsorbed by a sediment or
soil (i.e., the solid phase) divided by the amount of chemical in the
solution phase, which is in equilibrium with the solid phase, at a fixed
solid/solution ratio. It is generally expressed in micrograms of chemical
sorbed per gram of soil or sediment.
Bioconcentration Factor (BCF) -- The quotient of the concentration of a
chemical in aquatic organisms at a specific time or during a discrete time
period of exposure divided by the concentration in the surrounding water at
the same time or during the same period.
Cancer Effect Level (CEL) -- The lowest dose of chemical in a study, or
group of studies, that produces significant increases in the incidence of
cancer (or tumors) between the exposed population and its appropriate
control.
Carcinogen -- A chemical capable of inducing cancer.
Ceiling Value -- A concentration of a substance that should not be
exceeded, even instantaneously.
Chronic Exposure -- Exposure to a chemical for 365 days or more, as
specified in the Toxicological Profiles.
Developmental Toxicity -- The occurrence of adverse effects on the
developing organism that may result from exposure to a chemical prior to
conception (either parent), during prenatal development, or postnatally to
the time of sexual maturation. Adverse developmental effects may be
detected at any point in the life span of the organism.
Embryotoxicity and Fetotoxicity -- Any toxic effect on the conceptus as a
result of prenatal exposure to a chemical; the distinguishing feature
between the two terms is the stage of development during which the insult
occurred. The terms, as used here, include malformations and variations,
altered growth, and in utero death.
EPA Health Advisory --An estimate of acceptable drinking water levels for a
chemical substance based on health effects information. A health advisory
is not a legally enforceable federal standard, but serves as technical
guidance to assist federal, state, and local officials.
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9. GLOSSARY
Immediately Dangerous to Life or Health (IDIH) -- The maximum environmental
concentration of a contaminant from which one could escape within 30 min
without any escape-impairing symptoms or irreversible health effects.
Intermediate Exposure -- Exposure to a chemical for a duration of 15-364
days as specified in the Toxicological Profiles.
Immunologic Toxicity -- The occurrence of adverse effects on the immune
system that may result from exposure to environmental agents such as
chemicals.
In Vitro -- Isolated from the living organism and artificially maintained,
as in a test tube.
In Vivo -- Occurring within the living organism.
Lethal Concentration^jjQ) (LCjjqj -- The lowest concentration of a chemical in
air which has been reported to have caused death in humans or animals.
Lethal Concentration(5Q) (LCjq) -- A calculated concentration of a chemical
in air to which exposure for a specific length of time is expected to cause
death in 50% of a defined experimental animal population.
Lethal Dose^jjQ) (LDjjq) -- The lowest dose of a chemical introduced by a
route other than inhalation that is expected to have caused death in humans
or animals.
Lethal Dose(50) (LD50) "" The dose °f a chemical which has been calculated
to cause death in 50% of a defined experimental animal population.
Lethal Time(50) (LT50) -- A calculated period of time within which a
specific concentration of a chemical is expected to cause death in 50X of a
defined experimental animal population.
Lowest-Observed-Adverse-Effect Level (LOAEL) -- The lowest dose of chemical
in a study, or group of studies, that produces statistically or biologically
significant increases in frequency or severity of adverse effects between
the exposed population and its appropriate control.
Malformations -- Permanent structural changes that may adversely affect
survival, development, or function.
Minimal Risk Level --An estimate of daily human exposure to a chemical that
is likely to be without an appreciable risk of deleterious effects
(noncancerous) over a specified duration of exposure.
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9. GLOSSARY
Mutagen -- A substance that causes mutations. A mutation is a change in the
genetic material in a body cell. Mutations can lead to birth defects,
miscarriages, or cancer.
Neurotoxicity -- The occurrence of adverse effects on the nervous system
following exposure to chemical.
No-Observed-Adverse-Effect Level (NOAEL) -- The dose of chemical at which
there were no statistically or biologically significant increases in
frequency or severity of adverse effects seen between the exposed population
and its appropriate control. Effects may be produced at this dose, but they
are not considered to be adverse.
Octanol-Water Partition Coefficient (K^,) -- The equilibrium ratio of the
concentrations of a chemical in n-octanol and water, in dilute solution.
Permissible Exposure Limit (PEL) --An allowable exposure level in
workplace air averaged over an 8-hour shift.
qi* -- The upper-bound estimate of the low-dose slope of the dose-response
curve as determined by the multistage procedure. The q^* can be used to
calculate an estimate of carcinogenic potency, the incremental excess cancer
risk per unit of exposure (usually pg/L for water, mg/kg/day for food, and
/ig/m^ for air).
Reference Dose (RfD) --An estimate (with uncertainty spanning perhaps an
order of magnitude) of the daily exposure of the human population to a
potential hazard that is likely to be without risk of deleterious effects
during a lifetime. The RfD is operationally derived from the NOAEL (from
animal and human studies) by a consistent application of uncertainty factors
that reflect various types of data used to estimate RfDs and an additional
modifying factor, which is based on a professional judgment of the entire
database on the chemical. The RfDs are not applicable to nonthreshold
effects such as cancer.
Reportable Quantity (RQ) -- The quantity of a hazardous substance that is
considered reportable under CERCLA. Reportable quantities are (1) 1 lb or
greater or (2) for selected substances, an amount established by regulation
either under CERCLA or under Sect. 311 of the Clean Water Act. Quantities
are measured over a 24-hour period.
Reproductive Toxicity -- The occurrence of adverse effects on the
reproductive system that may result from exposure to a chemical. The
toxicity may be directed to the reproductive organs and/or the related
endocrine system. The manifestation of such toxicity may be noted as
alterations in sexual behavior, fertility, pregnancy outcomes, or
modifications in other functions that are dependent on the integrity of
this system.
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9. GLOSSARY
Short-Term Exposure Limit (STEL) -- The maximum concentration to which
workers can be exposed for up to 15 min continually. No more than four
excursions are allowed per day, and there must be at least 60 min between
exposure periods. The daily TLV-TWA may not be exceeded.
Target Organ Toxicity -- This term covers a broad range of adverse effects
on target organs or physiological systems (e.g., renal, cardiovascular)
extending from those arising through a single limited exposure to those
assumed over a lifetime of exposure to a chemical.
Teratogen -- A chemical that causes structural defects that affect the
development of an organism.
Threshold Limit Value (TLV) - - A concentration of a substance to which most
workers can be exposed without adverse effect. The TLV may be expressed as
a TWA, as a STEL, or as a CL.
Time-Weighted Average (TWA) --An allowable exposure concentration averaged
over a normal 8-hour workday or 40-hour workweek.
Toxic Dose (TD50) -- A calculated dose of a chemical, introduced by a route
other than inhalation, which is expected to cause a specific toxic effect in
50% of a defined experimental animal population.
Uncertainty Factor (UF) -- A factor used in operationally deriving the RfD
from experimental data. UFs are intended to account for (1) the variation
in sensitivity among the members of the human population, (2) the
uncertainty in extrapolating animal data to the case of human, (3) the
uncertainty in extrapolating from data obtained in a study that is of less
than lifetime exposure, and (4) the uncertainty in using LOAEL data rather
than NOAEL data. Usually each of these factors is set equal to 10.
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APPENDIX: PEER REVIEW
A peer review panel was assembled for 1,2-diphenylhydrazine. The
panel consisted of the following members: Dr. Judith S. Bellin, Private
Consultant; Dr. Rolf Hartung, Department of Environmental and Industrial
Health, University of Michigan; Dr. Michael Norvell, Private Consultant; and
Dr. Richard Carchman, Department of Pharmacology and Toxicology, Medical
College of Virginia. These experts collectively have knowledge of 1,2-
diphenylhydrazine's physical and chemical properties, toxicokinetics, key
health end points, mechanisms of action, human and animal exposure, and
quantification of risk to humans. All reviewers were selected in conformity
with the conditions for peer review specified in Section 104(i)(13) of the
Comprehensive Environmental Response, Compensation, and Liability Act as
amended.
A joint panel of scientists from ATSDR and EPA has reviewed the peer
reviewers' comments and determined which comments will be included in the
profile. A listing of the peer reviewers' comments not incorporated in the
profile, with brief explanation of the rationale for their exclusion, exists
as part of the administrative record for this compound. A list of databases
reviewed and a list of unpublished documents cited are also included in the
administrative record.
The citation of the peer review panel should not be understood to
imply its approval of the profile's final content. The responsibility for
the content of this profile lies with the Agency for Toxic Substances and
Disease Registry.
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