United States Office of Water August 1981
Environmental Protection Regulations and Standards (WH-553) EPA-440/4-85-017
Agency Washington DC 20460
Water
vEPA An Exposure
and Risk Assessment
for 1,2,4-Trichlorobenzene
-------
DISCLAIMER
This is a contractor's final report, which has been reviewed by the Monitoring and Data Support
Division, U.S. EPA. The contents do not necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
-------
REPORT DOCUMENTATION »• "EPORT NO. z.
PAGE EPA-440/4-85-017
4. Tftle and Subtitle
An Exposure and Risk Assessment for 1,2,4-Trichlorobenzene
7. Author^) McNamara , P.; Byrne, M. ; Goyer, M. ; Lucas, P.; Scow, K.;
and Wood, M. (ADL) Wendt, S. (Acurex Corporation)
9. Performing Organization Nam* and Address
Arthur D. Little, Inc. Acurex Corporation
20 Acorn Park 485 Clyde Avenue
Cambridge, MA 02140 Mt. View, CA 94042
12. Sponsoring Organization Nam* and Address
Monitoring and Data Support Division
Office of Water Regulations and Standards
U.S. Environmental Protection Agency
Washington, D.C. 20460
3. Recipient's Accession No.
s. Report Date Final Revision
August 1981
6.
a. Performing Organization Rept. No.
la Proiect/Ta*k/Work Unit No.
11. Contract(C) or Grant(G) No.
C-68-01-6017
13. Type of Report * Period Covered
Final
14.
15. Supplementary Note*
Extensive Bibliographies
1*. Abstract (Limit: 200 word*)
I
This report assesses the risk of exposure to 1,2,4-trichlorobenzene. This study is
part of a program to identify the sources of and evaluate exposure to 129 priority
pollutants. The analysis is based on available information from government, industry,
and technical publications assembled in June of 1981.
The assessment includes an identification of releases to the environment during
production, use, or disposal of the substance. In addition, the fate of 1,2,4-
trichlorobenzene in the environment is considered; ambient levels to which various
populations of humans and aquatic life are exposed are reported. Exposure levels are
estimated and available data on toxicity are presented and interpreted. Information
concerning all of these topics is combined in an assessment of the risks of exposure
to 1,2,4-trichlorobenzene for various subpopulations.
17. Document Analysis a. Descriptor*
Exposure
Risk
Water Pollution
Air Pollution
b. lo*frtlfl*rs/Ope«vEnded Terms
Pollutant Pathways
. Risk Assessment
c. COSATt Field/Group
Effluents
Waste Disposal
Food Contamination
Toxic Diseases
1,2,4-Trichlorobenzene
11. AvallaMlrry Statement
Release to Public
19. Security Class (This Report)
Unclassified
20. Security Clan (This Page)
Unclassified
21. No. of Pages
122
22. Price
$13.00
«e ANSI-Z39.lt)
See Instruction* on Reverse
OPTIONAL FORU 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
-------
EPA-440/4-85-017
June 1981
(Revised August 1981)
AN EXPOSURE AND RISK ASSESSMENT FOR
1,2,4-TRICHLOROBENZENE
BY
Pamela Walker McNamara,
Melanie Byrne, Muriel Goyer,
Peter Lucas, Kate Scow, and Melba Wood
Arthur D. Little, Inc.
U.S. EPA Contract 68-01-6160
Steve Wendt
Acurex Corporation
U.S. EPA Contract 68-01-6017
John Segna
Project Manager
U.S. Environmental Protection Agency
Monitoring and Data Support Division (WH-553)
Office of Water Regulations and Standards
Washington, D.C. 20470
OFFICE OF WATER REGULATIONS AND STANDARDS
OFFICE OF WATER AND WASTE MANAGEMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20470
-------
FOREWORD
Effective regulatory action for toxic chemicals requires an
understanding of the human and environmental risks associated with the
manufacture, use, and disposal of the chemical. Assessment of risk
requires a scientific judgment about the probability of harm to the
environment resulting from known or potential environmental concentra-
tions. The risk assessment process integrates health effects data
(e.g., carcinogenicity, teratogenicity) with information on exposure.
The components of exposure include an evaluation of the sources of the
chemical, exposure pathways, ambient levels, and an identifir.ation of
exposed populations including humans and aquatic life.
This assessment was performed as part of a program to determine
the environmental risks associated with current use and disposal
patterns? for 65 chemicals and classes of chemicals (expanded to 129
"priority pollutants") named in the 1977 Clean Water Act. It includes
an assessment of risk for humans and aquatic life and is intended to
serve as a technical basis for developing the most appropriate and
effective strategy for mitigating these risks.
This document is a contractors' final report. It has been
extensively reviewed by the individual contractors pnd by the EPA at
several stages of completion. Each chapter of the draft was reviewed
by members of the authoring contractor's senior technical staff (e.g.,
toxicologists, environmental scientists) who had not previously been
directly involved in the work. These individuals were selected by
management to be the technical peers of the chapter authors. The
chapters were comprehensively checked for uniformity in quality and
content by the contractor's editorial team, which also was responsible
for the production of the final report. The contractor's senior
project management subsequently reviewed the final report in its
entirety.
At EPA a senior staff member was responsible for guiding the
contractors, reviewing the manuscripts, and soliciting comments, where
appropriate, from related programs within EPA (e.g., Office of Toxic
Substances, Research and Development, Air Programs, Solid and
Hazardous Waste, etc.). A complete draft was summarized by the
assigned EPA staff member and reviewed for technical and policy
implications with the Office Director (formerly the Deputy Assistant
Administrator) of Water Regulations and Standards. Subsequent revi-
sions were included in the final report.
Michael W. Slimak, Chief
Exposure Assessment Section
Monitoring & Data Support Division (WH-553)
Office of Water Regulations and Standards
ii
-------
TABLE OF CONTENTS Page
LIST OF FIGURES vi
LIST OF TABLES vii
ACKNOWLEDGMENTS ix
1.0 TECHNICAL SUMMARY 1-1
1.1 Risk to Humans: Effects, Exposure and Fate
Considerations 1-1
1.1.1 Adverse Effects Levels 1-1
1.1.2 Exposure 1-2
1.1.3 Fate Considerations 1-2
1.2 Risk to Non-Human Biota: Effects, Exposure, and Fate 1-4
1.2.1 Toxic Effects 1-4
1.2.2 Exposure 1-4
1.2.3 Fate Considerations 1-4
1.3 Materials Balance 1-5
2.0 INTRODUCTION 2-1
3.0 MATERIALS BALANCE - 3-1
3.1 Introduction 3-1
3.2 Production 3-1
3.2.1 Chlorination of 1,2- and 1,4-Dichlorobenzene 3-5
3.2.2 Inadvertent Sources 3-7
3.2.2.1 Production of Other Chlorinated Benzenes 3-7
3.2.2.2 Chlorination of Water 3-7
3.2.2.3 Breakdown of Higher Chlorinated Benzenes 3-8
3.3 Uses 3-10
3.3.1 Dye Carrier 3-10
3.3.2 Pesticide Production 3-12
3.3.3 Functional Fluids 3-13
3.3.4 Miscellaneous Uses 3-13
3.3.4.1 Degreasing Agents 3-13
3.3.4.2 Septic Tank and Drain Cleaners 3-15
3.3.4.3 Wood Preservatives 3-15
3.3.4.4 Abrasive Formulations 3-15
3.4 Municipal Disposal of 1,2,4-Trichlorobenzene 3-15
3.4.1 POTWs 3-16
3.4.2 Urban Refuse 3-16
References 3-18
iii
-------
TABLE OF CONTENTS (Continued)
4.0 FATE AND DISTRIBUTION IN THE ENVIRONMENT 4-1
4.1 Introduction 4-1
4.2 Physicochemical Properties 4-1
4.3 Aquatic Fate 4-4
4.3.1 Introduction 4-4
4.3.2 Concentrations in Effluents to Surface Waters 4-4
4.3.3 Fate Processes 4-6
4.3.3.1 Volatilization 4-6
4.3.3.2 Bioaccumulation 4-1C
4.3.3.3 Absorption by Biota 4-1]
4.3.3.4 Adsorption onto Sediment 4-1J
4.3.3.5 Chemical Degradation 4-12
4.3.4 Modeling of Environmental Distribution 4-12
4.3.5 Concentrations Detected in Ambient Surface Water 4-19
4.3.6 Ambient Concentrations Reported in Other Aquatic
Systems 4-19
4.4 Atmospheric Fate 4-22
4.4.1 Photodegradation 4-22
4.4.2 Wet and Dry Deposition 4-22
4.4.3 Atmospheric Monitoring 4-22
4.5 Terrestrial Fate 4-24
4.5.1 Introduction 4-24
4.5.2 Adsorption onto Soil 4-24
4.5.3 Biodegradation - 4-24
4.5.4 Soil to Groundwater: A Field Study 4-26
4.6 Fate in POTWS and Other Water Treatment Facilities 4-26
4.6.1 Wastewaters 4-26
4.6.2 Effects of Chlorination During Water Treatment 4-3C
4.6.3 Concentrations Detected in Drinking Waters 4-3C
4.7 Summary 4-32
References 4-36
5.0 EXPOSURE AND EFFECTS — HUMANS 5-1
5.1 Human Toxicity 5-1
5.1.1 Introduction 5-1
5.1.2 Metabolism and Bioaccumulation 5-1
5.1.3 Human and Animal Studies 5-2
5.1.3.1 Carcinogenicity 5-2
5.1.3.2 Mutagenicity 5-2
5.1.3.3 Adverse Reproductive Effects 5-2
5.1.3.4 Other Toxic Effects 5-3
5.1.4 Summary of Human Effects Considerations 5-5
5.1.4.1 Ambient Water Quality Criterion —
Human Health 5-5
iv
-------
TABLE OF CONTENTS (Continued)
Health Effects Considerations
5.1.4.2
5.2 Exposure
5.2.1 Introduction
5.2.2 Exposure Routes
5.2.2.1 Exposure through Ingestion
Exposure through Inhalation
Percutaneous Exposure
5.2.3
References
5.2.2.2
5.2.2.3
Summary
6.0 EFFECTS AND EXPOSURE—AQUATIC BIOTA
6.1 Effects on Aquatic Biota
6.2 Exposure
References
7.0 RISK CONSIDERATIONS
7.1 Human Risk
7.1.1 Human Health Considerations
7.1.2 Routes of Exposure
7.1.2.1 Inhalation
7.1.2.2 Ingestion
7.1.3 Conclusions
7.2 Non-Human Risk
7.2.1 Exposure
7.2.2 Aquatic Effects and Risk Considerations
References
APPENDIX A. Assumptions Regarding Environmental Releases
APPENDIX B. Process Specific Data on 1,2,4-Trichlorobenzene
Releases
APPENDIX C. Estimation of Volatilization from Water
5-5
5-7
5-7
5-7
5-7
5-8
5-9
5-9
5-11
6-1
6-1
6-1
6-4
7-1
7-1
7-1
7-2
7-2
7-2
7-3
7-3
7-3
7-4
7-5
A-l
B-l
C-l
-------
LIST OF FIGURES
Figure
No. Page
3-1 Estimated Environmental Releases of 1,2,4-Trichloro-
benzene from Production, Use and Inadvertent Sources,
1979 (kkg) 3-2
3-2 Batch Production of Chlorobenzenes 3-6
4-1 Environmental Releases of 1,2,4-Trichlorobenzene 4-2
4-2 Proposed Biodegradation Pathway for 1,2,4- 4-27
Trichlorobenzene
4-3 Environmental Pathways of 1,2,4-Trichlorobenzene 4-34
B-l Batch Production of Chlorobenzenes B-4
B-2 Production Schematic for Pentachlorobenzene by
Chlorination of Benzene or Chlorobenzene B-5
B-3 Production Schematic for Hexachlorobenzene by
Chlorination of Benzene and Chlorobenzenes B-6
vi
-------
LIST OF TABLES
Table
No. Page
3-1 Occurrence of 1,2,4-Trichlorobenzene in
Drinking Waters 3-9
3-2 Estimated Quantities of 1,2,4-Trichlorobenzene-
Containing Wastes Released to the Environment
from Textile Operations in 1979 (kkg) 3-11
3-3 Estimated Quantities of 1,2,4-Trichlorobenzene in
Metric Tons (kkg) Released to the Environment During
Electronic Wafer Degreasing Operations 3-14
3-4 1,2,4-Trichlorobenzene Distribution in POTW Influent,
Effluent and Sludge Samples from Select Urban Sites 3-17
4-1 Physical and Chemical Properties of 1,2,4-Trichloro-
benzene 4_3
4-2 Distribution of Remarked Effluent 1,2,4-Trichlorobenzene
Concentrations for Major River Basins in the United
States—STORET, 1980 4-5
4-3 Seasonal Levels of 1,2,4-Trichlorobenzene in
Selected Effluent Waters 4-7
4-4 Observations of 1,2,4-Trichlorobenzene Levels
in Wastewaters 4-8
4-5 Concentrations of 1,2,4-Trichlorobenzene in Waste
Streams of Industrial Sources to Water 4-9
4-6 Parameters for 1,2,4-Trichlorobenzene Used in EXAMS
Analysis 4-13
4-7 Flow and Depth of EXAMS Simulated Systems 4-14
4-8 Steady-State Concentrations in Various Generalized
Aquatic Systems Resulting from Continuous 1,2,4-
Trichlorobenzene Discharge at 1.0 kg/hr 4-15
4-9 The Fate of 1,2,4-Trichlorobenzene in Various
Generalized Aquatic Systems 4-16
4-10 System Half-Lives for 1,2,4-Trichlorobenzene
Persistence 4-18
vii
-------
LIST OF TABLES (Continued)
Table
No.
4-11 Distribution of Remarked Ambient 1,2,4-Trichlorobenzene
Concentrations for Major River Basins in the United
States—STORET, 1980 4-20
4-12 Ambient Surface Water Concentrations of 1,2,4-
Trichlorobenzene 4-21
4-13 Microbial Biodegradation of 1,2,4-Trichlorobenzene 4-25
4-14 Trichlorobenzene Removal Efficiencies of Selected
Wastewater Treatment Facilities 4-28
4-15 Occurrence of 1,2,4-Trichlorobenzene in Community
Drinking Water Supplies 4-31
5-1 Adverse Effects of 1,2,4-Trichlorofaenzene on
Mammals and Bacteria 5-6
5-2 Estimated Exposure to Elevated Levels of 1,2,4-
Trichlorobenzene . 5-10
6-1 Acute Toxicity of 1,2,4-Trichlorobenzene for Fresh-
water and Saltwater Species 6-2
6-2 Chronic Toxicity of 1,2,4-Trichlorobenzene for Fresh-
water Species 6-3
B-l Quantities of 1,2,4-Trichlorobenzene-Containing
Wastes Released to the Environment from Wet
Processing Textile Mills in 1979 (kkg) B-2
B-2 Wastewater Treatment Status - Wet Processing
Mills Surveyed ' B-3
viii
-------
ACKNOWLEDGMENTS
The Arthur D. Little, Inc., task manager for this study was Pamela
Walker McNamara. Major contributors to this report were Melanie Byrne
(Aquatic Effects and Exposure), Muriel Goyer (Human Effects), Peter
Lucas (Environmental Fate), Kate Scow (EXAMS, Biotic Fate and Risk)
and Melba Wood (Monitoring Data). Preparation of the final draft
report involved Jane Metzger (editing), Nina Green (documentation),
Mary Ann Arvai (technical support), and George Harris (technical
review).
The materials balance for 1,2,4-trichlorobenzene (Chapter 3.0) was
prepared by Acurex Corp. under Contract 68-01-6017 to the Monitoring
and Data Support Division (MDSD), Office of Water Regulations and
Standards (OWRS), U.S. Environmental Protection Agency. Steve Wendt
was the task manager for Acurex, Inc. Patricia Leslie was responsible
for report production.
John Segna of the Monitoring and Data Support Division was the pro-
ject manager at EPA. Technical comments should be addressed directly to
him.
ix
-------
1.0 TECHNICAL SUMMARY
The Monitoring and Data Support Division, Office of Water Regulations
and Standards, U.S. Environmental Protection Agency, is conducting an
ongoing program to identify the sources of, and evaluate the exposure
to, 129 priority pollutants. This report assesses the exposure to and
risks associated with 1,2,4-trichlorobenzene in the environment.
The conclusions reached in this assessment are summarized in this
chapter. The potential risks are discussed within the constraints of
available data, and the following subjects are also briefly discussed:
human health effects; exposure routes and levels, where known; principal
environmental pathways; toxic effects and exposure for aquatic biota;
and the sources and volumes of releases of 1,2,4-trichlorobenzene to
the environment (materials balance).
1.1 RISK TO HUMANS; EFFECTS. EXPOSURE AND FATE CONSIDERATIONS
The risk to humans resulting from exposure to 1,2,4-trichlorobenzene
cannot be reliably evaluated at this time, due to the insufficiency of
data in two areas. First, there is a general lack of data on the car-
cinogenicity, teratogenicity, mutagenicity and long-term oral toxicity
of 1,2,4-trichlorobenzene. Second, there are limited data on the levels
of the compound in all environmental media to which humans are exposed.
The limited information that is available suggests that there is little
risk associated with environmental exposure to 1,2,4-trichlorofaenzene
via inhalation, principally because the levels of the compound detected
in the atmosphere are much lower than those estimated to cause adverse
effects in humans. The highest atmospheric concentration reported, 100
ng/m3 near a chemical plant, is 200,000 times lower than the no-effect
level for eye and respiratory tract irritation in man (19 mg/m ). The
risk associated with ingestion of drinking water contaminated with 1,2,4-
trichlorobenzene is uncertain; elevated levels of 1,2,4-trichlorobenzene
are detected infrequently in drinking waters or in surface water near
drinking water system intakes. However, in the absence of adequate
effects data and monitoring information, the significance of these
infrequent elevated levels of 1,2,4-trichlorobenzene to human health
cannot be reliably determined.
1.1.1 Adverse Effects Levels
Available health effects data provide no suggestion of adverse
effects resulting in humans from exposure to low levels of 1,2,4-tri-
chlorobenzene such as those commonly detected in the environment. How-
ever, none of the available animal studies provided sufficient data for
extrapolation of actual dose-response relationships to humans.
Animal data indicate that 1,2,4-trichlorobenzene is slowly absorbed
from the gut, skin, and lung. Following absorption, the compound is
metabolized to phenols which, in the conjugated form, are then excreted,
principally via the urine.
1-1
-------
Subchronic studies have been performed with rhesus monkeys. At
levels of 25 mg/kg/day of 1,2,4-trichlorobenzene orally administered for
120 days, little effect on the liver, hematological parameters or
clinical chemistries has been observed. At levels of 90 mg/kg/day,
however, signs of toxicity occurred. When given 174 mg/kg/day, animals
experienced lethality within 20 to 30 days. Similar results were
observed for rats, rabbits, and dogs inhaling 1,2,4-trichlorobenzene
in concentrations up to 800 mg/m3, 7 hrs/day, 5 days/week for 30 expo-
sures.
In humans, eye and respiratory tract irritation has been reported
following exposure to a level of 24 mg/m3 in the air, but not to a
level of 19 mg/m3. No other reported effects data for man could be
found.
1.1.2 Exposure
Exposure to 1,2,4-trichlorobenzene via inhalation does not appear
to be a significant route. The compound is detected infrequently, and
then, typically at low concentrations found in localized areas. Although
the compound has been observed at atmospheric concentrations of 10-100
ng/m3 near several chemical plants, usually 1,2,4-trichlorobenzene
either is not found in the atmosphere or it occurs at levels below
limits of analytical sampling and analysis.
Exposure to 1,2,4-trichlorobenzene through ingestion of drinking
water may occur infrequently. The compound has been detected in 10
samples from community drinking water supplies at a median concentra-
tion of 0.02 ug/1, with levels ranging from 0.01 to 10.0 ug/1. In
effluents from industrial discharges, 1,2,4-trichlorobenzene has been
found at concentrations of 500 ug/1 and higher.
Percutaneous exposure is not expected to be particularly signifi-
cant because the principal non-occupational source of 1,2,4-trichloro-
benzene exposure to the skin is from the air, in which relatively low
concentrations of the compound are observed, as discussed above.
1.1.3 Fate Considerations
The chemical 1,2,4-trichlorobenzene is released to all environmental
media. The largest identified releases (52%) are to the aquatic environ-
ment [to Publicly Owned Treatment Works (POTWs) and directly to surface
water]. The land is the second largest receiving medium (36%) and is
a potentially significant pathway. Of the releases to the atmosphere
(12%), little is believed to persist in the environment. High atmos-
pheric concentrations of 1,2,4-trichlorobenzene appear to be associated
solely with localized industrial activities and are of brief duration.
1-2
-------
The compound, when detected, is found in low concentrations (below
100 Lig/1) in ambient waters; all observations reported in EPA's STORE!
Water Quality System were below detection limits. Higher concentrations
(up to 670 ug/1) were found infrequently in the ambient waters in the
vicinity of discharges from POTWs, textile plants, and non-ferrous
metal plants. Of the 1,2,4-trichlorobenzene released to surface waters,
volatilization appears to be the strongest process competing for its
removal. The rate of volatilization is largely dependent upon the
presence of adsorbing matter (micro-organisms and suspended sediments)
and the degree of aeration. In surface waters with a substantial amount
of biomass and suspended organic sediment, biodegradation and other
biological pathways are likely to become important.
At biological waste treatment facilities where there are high con-
centrations of suspended biota, it is likely that biodegradation will
effectively remove most of the 1,2,4-trichlorobenzene. Under these
circumstances, volatilization has been shown to be relatively insignifi-
cant. There are other types of wastewater treatment practices in use
in addition to biological. Removal efficiencies associated with different
treatment processes at POTWs in general vary from 13% to 100% removal.
Freshwater sediments frequently adsorb 1,2,4-trichlorobenzene.
The extent to which this occurs depends upon the amount of organic
matter in the sediment and the concentration of 1,2,4-trichlorobenzene
in the overlying water. Consideration of the Freundlich equation
indicates that a river with a 1,2,4-trichlorobenzene concentration of
0.1 mg/1 will have an associated 1,2,4-trichlorobenzene concentration
in surface sediment of approximately 20 mg per kg of sediment. Suspended
sediment serves as a sink for some portion of the 1,2,4-trichlorobenzene
in water, although biodegradation competes with sediment adsorption as
a removal process.
A potential environmental pathway that could not be evaluated due
to lack of data is the migration to groundwaters of 1,2,4-trichloroben-
zene deposited on land. In a single groundwater contamination field
study, groundwater adjacent to the site of an accidental spill of fluids
containing 1,2,4-trichlorobenzene was sampled immediately following and
then 2 years after the incident. The compound was initially found at
a concentration of 500 yg/1 in groundwater and at 1 yg/1 two years
later. Biodegradation of 1,2,4-trichlorobenzene in soil has been
observed in the laboratory, but the rate of biodegradation in the
environment and how it may affect migration of the compound to ground-
water are not known.
Of the relatively small quantity of 1,2,4-trichlorobenzene released
to air, most is expected to be photodegraded at a rate equal to the
rate of release. The primary mechanism of photodegradation appears
to involve photolytically generated hydroxyl radicals. Other mechanisms
such as photochlorination and biphenyl formation are not expected to
be significant.
The effect of intermedia transfers of 1,2,4-trichlorobenzene sub-
sequent to initial discharges to receiving media has not been evaluated.
1-3
-------
1.2 RISK TO NON-HUMAN BIOTA; EFFECTS, EXPOSURE, AND FATE CONSIDERATIONS
Most of the available toxicity data for aquatic species are for the
other chlorinated benzenes rather than for 1,2,4-trichlorofaenzene
specifically. Furthermore, the data base concerning concentrations
in environmental media is very limited. Hence, risk can not be evalu-
ated fully at this time.
The limited monitoring data suggest that a 1,2,4-trichlorobenzene level
of 30 ug/1 (the only identified criterion for 1,2,4-trichlorobenzene which
was established in the Soviet Union) is rarely exceeded in ambient waters.
Furthermore, in the rare instances in which 1,2,4-trichlorobenzene is
observed at elevated concentrations (500 ug/1 or higher), it is likely
that the 1,2,4-trichlorobenzene is rapidly volatilized or adsorbed by
suspended sediment, decreasing its availability to aquatic organisms.
1.2.1 Toxic Effects
The levels of chlorinated benzenes at which acute toxic effects
are shown to occur in different aquatic species range from 1 mg/1 to 50
mg/1, with only one report of a level of 0.45 mg/1. Chronic effects
are induced by these compounds at estimated levels of 200 to 700 ug/1.
1.2.2 Exposure
Ambient surface waters typically contain 1,2,4-trichlorobenzene
at concentrations below 100 ug/1. The principal occurrence of elevated
levels of 1,2,4-trichlorobenzene above the effects level is in localized
areas near or adjacent to industrial plants or POTW discharges. In these
localized areas, 1,2,4-trichlorobenzene has been observed at concentra-
tions ranging from 0.01 ug/1 to 500 ug/1 in effluents from municipal
and industrial wastewaters to as high as 2700 ug/1 in selected untreated
industrial effluents.
1.2.3 Fate Considerations
Of principal concern is the fate of 1,2,4-trichlorobenzene occur-
ring at elevated concentrations near or 'downstream of industrial
effluents. Based on results of environmental system simulation by
the U.S. EPA's EXAMS model and based on information in the literature,
volatilization is the most significant removal process of 1,2,4-trichloro-
benzene from water. EXAMS indicated that as much as 90% of the chemical's
loss was accounted for by volatilization, resulting in a system clearance
time of 6.5 to 19 months. Some of the chemical is likely to be adsorbed
by suspended sediment. The remainder is absorbed by micro-organisms,
but probably at a concentration far lower than that near the point of
initial entry into the aquatic environment. Thus it appears exceedingly
unlikely that levels as high as 2700 ug/1 (as reported above) will per-
sist long enough to result in appreciable exposure to aquatic populations.
1-4
-------
1.3 MATERIALS BALANCE
An estimated 5335 kkg of 1,2,4-trichlorobenzene were released to
the environment in 1979. The largest release was to water (2804 kkg or
52%), with 42% of the total estimated release discharged to POTWs (2240
kkg) and 10% discharged directly to surface waters (534 kkg). The land
is also the recipient of a major portion of 1,2,4-trichlorobenzene
releases, receiving 1920 kkg or approximately 36% of the annual total.
Only 12% of the total releases are made directly to the atmosphere.
Of the aquatic discharges, 2264 kkg are released to POTWs and 540
kkg to surface waters. The bulk of effluent discharge to POTWs is
contributed by the textile industry, which utilizes 1,2,4-trichloroben-
zene as a dyeing agent primarily for polyester fibers. This industry
is the largest user of the chemical in the United States today, con-
suming 42.4% (3490 kkg) of the available U.S. supply. The only other
identified sources of 1,2,4-trichlorobenzene releases to POTWs are the
release of the chemical from electronic wafer degreasing operations and
as a result of its use as a drain cleaner, although these are relatively
minor; together these sources discharge 60 kkg to treatment systems, or
3% of the total discharge to POTWs. During the production of pesticides
and functional, dielectric fluids bearing 1,2,4-trichlorobenzene, an esti-
mated 7 kkg of 1,2,4-trichlorobenzene are released to POTWs from each
process. No other aquatic discharges were identified.
The land receives the second largest total release of 1,2,4-tri-
chlorobenzene totaling 1920 kkg each year. Approximately 71% of the
total release to land occurs as a result of disposal of used electrical
equipment containing 1,2,4-trichlorobenzene-bearing functional fluids.
Following treatment of aquatic discharges, the textile industry disposes
of 410 kkg (or 21% of total land releases) of 1,2,4-trichlorobenzene to
the land in the form of sludges. Production of the compound is respon-
sible for 3% of releases to land. The remaining 5% is from miscellaneous
sources.
An estimated 611 kkg of 1,2,4-trichlorobenzene is released to the
air annually. Use of 1,2,4-trichlorobenzene as a dye carrier accounts
for 57% of total releases to air. Use of 1,2,4-trichlorobenzene as a
chemical intermediate in the production of pesticides and functional
fluids releases only small quantities to the atmosphere. The remaining
39% of the atmospheric releases of 1,2,4-trichlorobenzene are from
miscellaneous uses including degreasing agents, septic tank and drain
cleaners, wood preservative and abrasive formulations.
1-5
-------
2.0 INTRODUCTION
The Office of Water Regulations and Standards (OWRS), Monitoring
and Data Support Division, of the U.S. Environmental Protection Agency
is conducting a program to evaluate the exposure to and risk of 129
priority pollutants in the nation's environment. The risks to be
evaluated include potential harm to human beings and deleterious
effects on fish and other biota. The goal of the task under which
this report has been prepared is to integrate information and to esti-
mate the risk based on receptor exposure to these substances. The
results are intended to serve as a basis for developing suitable regu-
latory strategies for reducing the risk, if such action is indicated.
This report is intended to provide a brief, but comprehensive
summary of the production, use, distribution, fate, effects, exposure
to, and potential risks associated with 1,2,4-trichlorobenzene. Water-
borne routes of exposure are stressed due to the emphasis of the OWRS
on aquatic and water-related pathways.
The major problem associated with the exposure and risk evaluation
of 1,2,4-trichlorobenzene arises from the general lack of data on both
human effects and the concentrations of 1,2,4-trichlorobenzene occurring
in the environment. Though ingestion of 1,2,4-trichlorobenzene in
drinking water is a potential route of exposure, it is" difficult to
assess the risk because of insufficient effects data and knowledge of
the frequency of exposure.
In the absence of extensive monitoring data, exposures have been
evaluated on the basis of scattered observations in the literature and
in the STORET Water Quality System and on the basis of fate models,
field observations, and laboratory data. The lack of data on the
health effects of 1,2,4-trichlorobenzene precluded, however, any quan-
titative assessment of the risks associated with the estimated exposures.
In order to place the risks of water-related exposure into per-
spective, exposure to 1,2,4-trichlorobenzene via inhalation has also
been considered, and the associated" risk is expected to be minimal if
any at all. 'Atmospheric emissions are infrequent and the compound is
not expected to persist in the air due to rapid photodegradation.
This report is organized as follows:
• Chapter 3.0 contains information on releases from the
production, use, and disposal of 1,2,4-trichlorobenzene,
including identification of the form and amounts released
to each receiving medium at the point of entry into the
environment.
• Chapter 4.0 considers the fate of 1,2,4-trichlorobenzene leading
from its release into the environment until exposure of receptors,
Reports of available data regarding concentrations detected in
environmental media are also discussed.
2-1
-------
• Chapter 5.0 discusses the adverse effects of 1,2,4-trichloro-
benzene and identifies, where possible, concentrations eliciting
these effects in humans, and quantifies the likely pathways
and levels of human exposure.
• Chapter 6.0 considers the effects of 1,2,4-trichlorobenzene
on biota and quantifies the environmental exposure of aquatic
biota to the compound.
• Chapter 7.0 discusses the risk considerations for various sub-
populations of humans and aquatic organisms.
• Appendices A and B present the assumptions and calculations
for the estimated environmental releases of 1,2,4-trichloro-
benzene described in Chapter 3.0. Appendix C presents the
assumptions and calculations for volatilization in Chapter
4.0.
2-2
-------
3.0 MATERIALS BALANCE
3.1 INTRODUCTION
This Chapter presents an environmental materials balance for 1,2,4-
trichlorobenzene in the United States for the year 1979. It considers
the major sources of 1,2,4-trichlorobenzene releases to water [publicly
owned treatment works (FOTWs) and surface water], land, and air, and
estimates the amount contained in products for the year 1979. The flow
of 1,2,4-trichlorobenzene from production, use, and disposal to the first
point of entry into the environment is shown in Figure 3-1.
Approximately 89% of the 1,2,4-trichlorobenzene consumed in the.
U.S. in 1979 came from domestic production, nearly 11% was imported,
and <1% was drawn from stocks. Most of the 1,2,4-trichlorobenzene
consumed was used as a dye carrier (46%); other high-volume uses were
pesticide formulations (29%), and functional fluids (18%).
The estimated quantities of 1,2,4-trichlorobenzene dispersed to
water (POTWs and surface water), land, and air are shown in Figure 3-1.
Of the estimated 2,800 kkg of 1,2,4-trichlorobenzene discharged to water,
about 2,260 kkg were released to POTWs, while 540 kkg were discharged
directly to surface waters. The largest source of 1,2,4-trichloro-
benzene wastes discharged to POTWs and surface waters was the textile
industry (2,190 kkg and 540 kkg, respectively). The largest source of
1,2,4-trichlorobenzene disposed of on land was obsolete electrical
apparatus impregnated with 1,2,4-trichlorobenzene-containing functional
fluids (1,370 kkg). Although these apparatus were manufactured in years
prior to 1979, the 1,2,4-trichlorobenzene released to the terrestial
environment is considered in the materials balance because"it was
released in 1979. The most significant source of 1,2,4-trichlorobenzene
emissions to the atmosphere was the textile industry (350 kkg), followed
in magnitude by degreasing operations (190 kkg).
3.2 PRODUCTION
•Though different methods can be used to produce 1,2,4-trichlorobenzene
(see Appendix A, Note 7 for further details), only the currently practiced
method is discussed in this section. Presently, 1,2,4-trichlorobenzene
is synthesized by the catalytic chlorination of 1,2- and 1,4-dichloro-
benzene, with ferric chloride (or iron filings) as the catalyst (EPA
I977a).
Chlorobenzenes can be produced by either batch or continuous methods.
Actual plant process data for the production of 1,2,4-trichlorobenzene
are not available. However, on the basis of the process described by
Ware and West (EPA 1977a) and on the low volume of domestic production
(7,300 kkg in 1979), it is assumed that all 1,2,4-trichlorobenzene
was produced via the batch method.
3-1
-------
Production'1
Usec
Otherd
Converted/*
Inadvertent
EnvlronmiUI Releases (U«)
rnJft,(Mtlnll nf
gara- and ortho-
dlchlorobeniene ' " '•"'—-
7.300 Dye Carriers
3.490
Stockpile
470
Exports
Drawn fro« 1
Storks
50 Functional Fluids
1.370
890
Miscellaneous
530°
contained »«iin.«»
d
(converted)
*" 2.1HU
10
(contained)^
"" 1.360
Production of
Benzenes
Chl urination of
Water
Breakdown of
Benzenes
TOTALS
Uaterr Land Air Total
POTU Surface
neg .neg 60 «eg 60s
2.190 S40 410 ISO 3.490h
7 J neg «eg ' 14 j 21J
7k ««9 I.3601 Jk I.370k
601* neg 90q 240r 390
2.264 540 1.920 611 S.33S
Figure 3-1. Estimated EnvlronmenUI Releases of 1.2.4-Trlchlorobeniene fro» Production. Use and Inadvertent Sources. 1979 (ttg)*
Footnotes not page.
-------
Figure 3-1. (continued)
a) Numbers may not add due to rounding; see text for discrepencles.
b) Total quantity of 1,2,4-trlchlorobenzene domestically produced and withdrawn from inventory In 1979 was
7,301 and 46 kkg, respectively; see Appendix A, Note 1 for calculations.
c) Based on the following percentages of the total quantity of 1,2,4-trlchlorobenzene consumed [I.e.,
(total quantity produced + drawn from stocks + Imported) - (total quantity stockpiled + exported) or
(7,300 + 46 + 886) - (466 + 177) = 7,589 kkg] by use from 1973 use pattern statistics: dye carriers
(46%), pesticide production (29%), functional fluids (to Include: synthetic transformer oil and
dielectric fluids, 18%) and miscellaneous uses (to Include: degreasing agents, septic tank and drain
cleaners, wood preservatives and abrasive formulations, 7%) (Lewis, 1975; EPA, 1977a).
d) Hull and Co., 1980; assuming one-half of the 1,2,3-tHchlorobenzene and 1,2,4-trlchlorobenzene mix
stockpiled and exported was 1,2,4-trlchlorobenzene.
e) The majority (99%) of the 1,2,4-trlchlorobenzene used to make pesticides was converted into other
compounds (see text for further details; Sittig, 1977); 99% of the 1,2,4-trichlorobenzene-containing
functional fluids manufactured in 1979 was contained within the electrical apparatus after manufacture,
see text for further details.
f) Water is defined as either publicly owned treatment works (POTWs) or surface waters.
g) See Note 2, Appendix A for further details.
h) See Note 3, Appendix A for further details.
i) To include: dicamba, stirofos, and trichlorodinitrobenzene.
-------
Figure 3-1. (concluded)
j) Based on process descriptions, 1% of the total quantity used 1s released to the environment where
two-thirds of the release Is emitted to the atmosphere and one-third is discharged to POTWs (Sittig,
1977).
k) Based on U.S. Patent information, 99% of the starting 1,2,4-trichlorobenzene Is impregnated into the
electrical apparatus and 1% is released to the environment. (See Note 4, Appendix A for further
details.)
1) Assuming the quantity of 1,2,4-trlchlorobenzene produced in 1979 and used in functional fluids for that
year is equal to the quantity of 1,2,4-trichlorobenzene contained within electrical apparatus
manufactured prior to 1979 which became obsolete and were disposed to land.
m) See Appendix A, Note 5 for calculations.
n) To include monochlorobenzene, ortho- and para- dichlorobenzene, the trlchlorobenzenes (1,2,3- and
1,3,5-), the tetrachlorobenzenes (1,2,3,4-, 1,2.4,5- and 1,2,3,5-), pentachlorobenzene and hexachlo-
rocyclohexane (lindane).
o) See footnote (c) for definition and Appendix A, Note 6 for quantities consumed and released by each
component user.
p) An estimated 29 kkg of 1,2,4-trichlorobenzene discharged to POTWs from electronic wafer degreasing
operations and 27 kkg from use as a drain cleaner (EPA, 1979c and Hull and Co., 1980).
q) An estimated 67 kkg of 1,2,4-trichlorobenzene disposed to land from electronic wafer degreasing
operations and 27 kkg from use as a septic tank cleaner (EPA, 1979c and Hull and Co., 1980).
r) An estimated 190 kkg of 1,2,4-trichlorobenzene were emitted to the atmosphere from electronic wafer '
degreasing operations, 42 kkg from automotive engine cleaning, <1 kkg from wood preserving operations
and 5 kkg from grinding wheel manufacture (EPA, 1979c; Hull, 1980; Hull and Co., 1980 and Richards,
1980).
s) To include: the tetrachlorobenzenes (1,2,3,4- 1,2,3,5- and 1,2,4,5-), pentachlorobenzene,
hexachlorobenzene and hexachlorocyclohexane (lindane).
-------
3.2.1 Chlorination of 1,2- and 1,4-Dichlorobenzene
Chlorobenzene and higher chlorinated benzenes are formed when
chlorine reacts with benzene at slightly elevated temperatures in the
presence of select catalysts:
C6H6 + C12 - "-C6H5C1 + HC1
HC1
Once one chlorine atom has been substituted onto the benzene ring,
further substitution takes place principally in the ortho and para
positions (Morrison and Boyd 1979, see Appendix A, Note 8 for further
details) .
The 1,2- and 1,4-dichlorobenzene isomers are produced primarily
from the distillation residues formed during chlorobenzene manufacture
(EPA 1980a) . The 1,2- isomer is chlorinated more rapidly than the
1,4- isomer to form 1,2,4-trichlorobenzene (along with minor quantities
of 1,2,3-trichlorobenzene) , which is easily separated from dichloro-
benzene (and 1,2,3-trichlorobenzene) by fractional distillation (EPA
1977a and I980a).
Figure 3-2 represents a simplified process for the production of
1,2,4-trichlorobenzene via the batch process- (Lowenheim and Moran 1975;
see Appendix A, Note 9 and Appendix B, Figure B-l for further details).
Benzene, chlorine, monochlorobenzene, hydrochloric acid, either anhydrous
ferric chloride or iron turnings (as catalyst) , sodium hydroxide, and
water are added to the system to produce 1,2,4-trichlorobenzene. The
products of the process are water, hydrochloric acid, benzene, chloro-
benzene, 1,2- and 1,4-dichlorobenzene, 1,2,4-trichlorobenzene (liquid),
waste emissions from the scrubber vent, and discharges from the separator
and fractionation column.
During the production of 1,2,4-trichlorobenzene via the batch process,
wastes are known to be generated at two points; sludges from the separator
and tars from the fractionation column (see Appendix B, Figure B-l for
further details). To date, 1,2,4-trichlorobenzene has not been detected
in the scrubber vent gases (EPA 1978a). Sludges generated by the
separator are recycled for di chlorobenzene recovery and, therefore, their
contribution to 1,2,4-trichlorobenzene releases into the environment is not
expected be significant (EPA 1977a) . Approximately 0.044 kkg of poly-
chlorinated aromatic resinous material (tars) are generated by the
fractionation column per metric ton of monochlorobenzene produced (EPA
1975a) .
In 1978, nearly 136,960 kkg of monochlorobenzene were produced in
the U.S. (USITC 1980) . If one assumes that the quantity of monochloro-
benzene produced in 1979 was similar to the volume for 1978 and that all
of the monochlorobenzene was manufactured via the batch process, then
about 6,000 kkg of polychlorinated aromatic resinous material (tars)
3-5
-------
U)
0\
BENZENE
CHLORINE
MONOCHLOROBENZENE
HC1
CATALYST
NaOH
WATER
FUGITIVE
EMISSIONS
I
VENT
GASES
CHLOROBENZENES
PRODUCTION
SLUDGE
TAR
KtULLtU -^•-~—
1
BENZENE + WATERb
BENZENE + MONOCHI pROBENZFNF b
MONOCHLOROBFN7FNEC ^
DICHLORUBtN^NLS ^
HC1 ^
1,2.4-TRICHLQROBENZENF
a) See Figure B-l for further details.
b) Recycled for further processing.
c) Recovered and sent to storage as product.
Source: Lowenheim and Moran, 1975; EPA, 1977a.
Figure 3-2. Batch Production of Chlorobenzenes
-------
would have been produced. The exact composition of the tars is unknown,
but is assumed to be comprised chiefly of hexachlorobenzene, with <1%
1,2,4-trichlorobenzene because of extensive recycling, the presence
of available chlorine in the system, and the absence of 1,2,4-trichloro-
benzene in feedstock residues from various chlorination synthesis pro-
cesses (EPA 1975a and EPA 1978b). Therefore, it is likely that <60 kkg
of 1,2,4-trichlorobenzene were released from this process. According
to the U.S. EPA (1975a), all of this tar was disposed of on land.
3.2.2 Inadvertent Sources
For the purposes of this materials balance, any process that
unintentionally produces 1,2,4-trichlorobenzene and subsequently releases
it to the environment is considered an inadvertent source (see Note 10,
Appendix A for further details).
3.2.2.1 Production of Other Chlorinated Benzenes
The potential for the inadvertent production of 1,2,4-trichloro-
benzene exists during the manufacture of other chlorinated benzenes
[i.e., monochlorobenzene, 1,2- and 1,4-dichlorobenzene, the trichloro-
benzenes (1,2,3- and 1,3,5-), the tetrachlorobenzenes (1,2,3,4-, 1,2,4,5-
and 1,2,3,5-), pentachlorobenzene, and hexachlorobenzene]. However,
only a limited amount of information was available concerning which of
these manufacturing processes might actually do so.
Monochlorobenzene, 1,2- and 1,4-dichlorobenzene, and 1,2,3-tri-
chlorobenzene are usually produced simultaneously with 1,2,4-trichloro-
benzene (Lowenheim and Moran 1975, EPA 1977a). Thus the 1,2,4-trichloro-
benzene inadvertenly produced and released during the manufacture of
these compounds has already been accounted for in the estimate of 60
kkg generated during 1,2,4-trichlorobenzene manufacture (Section
3.2.1).
The quantity of 1,2,4-trichlorobenzene produced during 1,3,5-
trichlorobenzene, tetrachlorobenzene (1,2,3,4-, 1,2,4,5-, and 1,2,3,5-)
and pentachlorobenzene manufacture could not be determined from the data
available but is considered to be negligible (<1 kkg each year) due to
the extensive recycling of partially chlorinated benzenes during manu-
facture (EPA 1975b).
Most likely 1,2,4-trichlorobenzene was not released to the environ-
ment from hexachlorobenzene production in 1979 because hexachloro-
benzene has not been produced for domestic consumption since 1976
(see Note 11, Appendix A for further information).
3.2.2.2 Chlorination of Water
In recent years there has been much concern about the effects of
chlorination on organic materials contained in natural waters and waste-
3-7
-------
waters. Because of the current use of chlorine in water and sewage
treatment procedures, the potential exists for widespread inadvertent
production of chlorinated organic materials (Bellar _et_ ad. 1974).
Because benzene and the dichlorobenzenes have been identified in both
municipal water supplies and wastewaters, the potential role of chlori-
nation of these waters in the inadvertent production of 1,2,4-trichloro-
benzene has been investigated in several studies (EPA 1977b, EPA 1976).
Contamination of municipal drinking waters was reviewed in the
National Organic Monitoring Survey (NOMS) (EPA 1977b). The study
included 113 community water supplies, representing a variety of
sources and treatment processes; each was sampled three times during
a 12-month period (EPA 1977b). Table 3-1 shows that 1,2,4-trichloro-
benzene was detected infrequently and in low concentrations. The source
of the detected 1,2,4-trichlorobenzene was not readily apparent, though
chlorination apparently was not a significant source.
Bellar and coworkers (1974) compared the trichlorobenzene concen-
tration in effluent (in a sewage treatment plant) before treatment with
that after treatment and found only a slight increase from 56.7 ug/1 to
56.9 ug/1. Also, an EPA study (1976) showed that 1,2,4-trichlorobenzene
was not detected in samples of wastewater effluent and another EPA study
(1980a) stated that "...chlorination of water is not considered to be a
significant source of chlorinated benzenes." Consequently, if the above
studies are representative of chlorination processes for all sewage
treatment plants, then it is likely that chlorination of wastewaters
was not a significant inadvertent source of 1,2,4-trichlorobenzene in
1979.
3.2.2.3 Breakdown of Higher Chlorinated Benzenes
The inadvertent production of 1,2,4-trichlorobenzene via the break-
down of higher chlorinated benzenes (1,2,3,4-, 1,2,3,5-, and 1,2,4,5-
tetrachlorobenzene, pentachlorobenzene and hexachlorobenzene) was also
investigated. The tetrachlorobenzenes have been reported to be persistent
in soil and water systems (EPA 1980b, see Note 12, Appendix A for further
details). Therefore, even if the tetrachlorobenzenes are present in
these media, they are not likely to release significant amounts in the
1,2,4-trichlorobenzene form. Pentachlorobenzene has also been reported
to be persistent in the environment, remaining in soil for up to 3 years
after application (Beck and Hansen 1974). Furthermore, because only a
small quantity of pentachlorobenzene was released to the environment in
1979 (if one assumes 1977 production volumes to be similar to those
for 1979), it is likely that inadvertent production of 1,2,4-trichloro-
benzene via environmental degradation did not occur (see Note 13,
Appendix A for further details).
Likewise, degradation of hexachlorobenzene does not appear to be an
inadvertent source of 1,2,4-trichlorobenzene because: (1) it has not
been domestically produced since 1976 (SRI 1980) and (2) it is a very
stable, unreactive compound (EPA 1979a, see Note 14, Appendix A for
further details).
3-8
-------
Table 3-1. Occurrence of 1,2,4-Trlchlorobenzene 1n Drinking Waters
Phase3
I
II
III
Detection Frequency
1/112
2/113
10/110
Mean Concentration (ng/l)c Median Concentration (ng/1)
10 <0.4-1
0.29 <0. 005-0.1
0.090 <0.005
a) In phase I, samples were collected between March and April, 1976 and stored at 2-8 C for 1-2 weeks prior to
analyses; for phase II, samples were collected between May and July, 1976 and allowed to stand at 20-25 C
for 3-6 weeks prior to analyses and; for phase III, samples were collected between November 1976 and
January 1977 and were stored at 20-25<>C for 3-6 weeks prior to analyses.
b) Number of positive analyses/number of analyses.
c) Positive results only (samples which were above the analytical detection limits).
d) Results, from all samples (in the analyses this includes remarked data, observations noted
but below analytical detection limits).
Source: EPA, 1977b; additional detail on sampling sites and locations are shown in Table 4-15.
-------
There is a potential for the gama iso.mer of 1,2,3,4,5,6-hexa-
chlorocyclohexane (lindane) to break down to 1,2,4-trichlorobenzene.
Lindane has not been manufactured in the United States since 1976
and only small quantities (<500 kkg) were imported and used in pesti-
cides in 1970. Therefore, even if lindane is degraded to 1,2,4-
trichlorobenzene, it is doubtful that significant quantities of 1,2,4-
trichlorofaenzene were released (Nipp 1980, see Note 15, Appendix A for
further details).
3.3 USES
The compound 1,2,4-trichlorobenzene was not widely used in the
United States in 1979. The estimate of 7,589 kkg of the compound used
in 1979 was derived from 7,301 kkg produced domestically, 886 kkg imported,
and 45 kkg withdrawn from stocks minus 446 kkg, which were stockpiled
and the 177 kkg that were exported (Appendix A, Note 1 for details on
production, stockpiling, and imports). On the basis of use practices
in 1973 and 1979, the uses are estimated as follows: 3,491 kkg in
functional fluids, and 530 kkg in miscellaneous uses [degreasing
agents (424 kkg), septic tank and drain cleaner formulations (53 kkg),
wood preservatives (53 kkg), and abrasive formulations (<5 kkg)] (see
Figure 3-1). The major user of 1,2,4-trichlorobenzene, the textile
industry, released more 1,2,4-trichlorobenzene to the environment
than all of the other users combined.
3.3.1 Dye Carrier
- In 1979, an estimated 3,490 kkg of 1,2,4-trichlorobenzene were
used by the U.S. textile industry as a dye carrier (primarily for
polyester fibers). Generally, the dye, levelling agent, and carrier
(1,2,4-trichlorobenzene) are applied to the material for at least 1
hour at 100°C (see Note 16, Appendix A). The material is then either
rinsed and heated to 190°C for 1 minute or subjected to an alkaline
scour at 70-80°C with a sulfated fatty alcohol to remove the carrier
(Lewis 1975, EPA 1977a and 1980a) .
Most of the 1,2,4-trichlorobenzene, in the form of spent dye carrier,
is discharged to water where it may or may not be removed by wastewater
treatment practices. The amount of 1,2,4-trichlorobenzene possibly
retained by the material or emitted to the atmosphere during dyeing
operations is unknown. The U.S. EPA (1980a) estimated that 3% of the
amount used might be absorbed by the fiber, 1% would be released to the
air, while 96% would be discharged to water. However, because these
figures are not substantiated, a worst case scenario is used in this
report, i.e., that all of the 1,2,4-trichlorofaenzene used in the textile
industry (3,490 kkg) was released to the environment (see Table 3-2).
The quantities of 1,2,4-trichlorobenzene released to the environ-
ment from domestic wet-processing textile mills in 1979 are estimated
in Table 3-2 (see Appendix A, Note 17 and Appendix B, Table B-l for
3-10
-------
Table 3-2. Estimated Quantities of 1,2,4-Trlchlorobenzene-Contalnlng Wastes Released to the Environment from Textile
Operations In 1979a
Operation
Wool Scouring
Woven Fabric Finishing
Knit Fabric Finishing
Total
Environmental Releases (kkg)
Water5 Landc Airc
D
21
235
283
539
I
50
913
1,225
2,188
1.7
184
207
408
17
169
169 .
355
Total
105
1,501
1,885
3,490
a) See Appendix A, Note 17 and Appendix B, Table B-l for further details.
b) D=quantity of 1,2,4-trlchlorobenzene discharged directly to surface waters and I=quant1ty of 1,2,4-trlchlorobenzene
indirectly discharged to publicly owned treatment works.
c) Based on the assumption that the 1,2,4-trichlorobenzene removed during wastewater treatment was sent to land when
advanced treatment was used, and when biological treatment practices (or equivalent) were used the wastes were
equally divided between air and land.
d) Includes simple processing and complex processing plus deslzlng.
Source:EPA, 1979b; see Table B-2, Appendix B.
-------
further details). Most (2,727 kkg, or 78%) of these wastes was dis-
charged to water, with 539 and 2,188 kkg discharged to surface waters
and POTWs, respectively. As shown in Table 3-2 and B-l, the remaining
1,2,4-trichlorobenzene originally contained within the wastewaters was
most likely removed by the treatment facilities at the textile mills
and disposed of on land (408 kkg) and/or emitted to the atmosphere
(355 kkg).
3.3.2 Pesticide Production
Nearly 2,200 kkg of 1,2,4-trichlorobenzene were consumed by the
U.S. pesticide industry in 1979 (Figure 3-1). The compound was used
as an intermediate during the production of three pesticides: dicamba
(herbicide), stirofos (insecticide), and trichlorodinitrobenzene (fungi-
cide) (see Appendix A, Note 18 for chemical names and Note 19 for process
descriptions, Sittig 1977). Production statistics for these pesticides
were not reported by the producers because of the confidentiality of the
information (see Appendix A, Note 20 for further details, SRI 1980).
Therefore, it is assumed that 33% (or 733 kkg) of the total quantity of
1,2,4-trichlorobenzene used by the pesticide industry (2,200 kkg) was
consumed/converted during the production of each pesticide. Furthermore,
based on process descriptions, approximately 1% (or 22 kkg) of the total
1,2,4-trichlorobenzene used in the production of the aforementioned
pesticides was assumed to be released to the environment, of which, two-
thirds was emitted to the atmosphere and one-third was discharged to
POTWs (Figure 3-1, Richter 1961, Phillips and Word 1963, Dittmar 1956,
and Sittig 1977).
In the first step of dicamba manufacture, 90% of the 1,2,4-trichloro-
benzene used (or 90% of 733 = 660 kkg) is converted to 2,4-dichlorophenol
(Sittig 1977, see Appendix A, Note 19 for details). Therefore, not more
than 73 kkg of 1,2,4-trichlorobenzene could have been released to the
environment. However process descriptions indicate that most of this
1,2,4-trichlorobenzene was probably converted into other compounds
during side reactions so that <1% (or 7 kkg) of that used for dicamba
manufacture was released to the atmosphere from fugitive emissions and
handling (Sittig 1977, Richter 1961).
In the manufacture of stirofos, 1,2,4-trichlorobenzene was incorpo-
rated into the end product with 77% efficiency (Sittig 1977, Phillips and
Word 1963, see Appendix A, Note 19 for details). Thus, 23% (or 169 kkg)
of the total 1,2,4-trichlorobenzene used in stirofos formulation (733
kkg) could have been released to the environment. However, most of this
1,2,4-trichlorobenzene was probably converted into other compounds during
side reactions; and if recycling is taken into account, probably <1% (or
7 kkg) of the total 1,2,4-trichlorobenzene used was released to the atmos-
phere from handling and fugitive emissions (Phillips and Word 1963, Sittig
±yt / / •
According to Sittig (1977) and Dittmar (1956), 91% of the 1,2,4-
trichlorobenzene used as feedstock for trichlorodinitrobenzene formu-
lation was consumed. Therefore, 9% (or 70 kkg) of the original amount
3-12
-------
of 1,2,4-trichlorobenzene (733 kkg) could have been released to the
environment. However, the process description indicates that most of
this was converted into other compounds during side reactions, so that
<1% (or 7 kkg) of the total 1,2,4-trichlorobenzene used was discharged
to water (see Appendix A, Note 19 for further details).
3.3.3 Functional Fluids
In 1979, 1,370 kkg of 1,2,4-trichlorobenzene were used in functional
fluids such as dielectric liquids and transformer oils. Liquid dielectric
compositions containing 1,2,4-trichlorobenzene (0.3-20% by weight)
are primarily used in electrical apparatus such as capacitors and
transformers (Lapp and Sadler 1976, see Note 21, Appendix A for
further details).
During the manufacture of electrical apparatus impregnated with
1,2,4-trichlorobenzene-containing dielectric liquids, little 1,2,4-
trichlorobenzene was probably released to the environment. The liquid
dielectric was introduced into the hermetically sealed apparatus through
small seal holes in the casings. It is assumed that <1% (or 14 kkg)
of the total 1,2,4-trichlorobenzene impregnated into such apparatus
(1,370 kkg) was released, with 7 kkg of the total discharged to water
during cleaning and 7 kkg emitted to air as fugitive emissions (Lapp
and Sadler 1976).
The remaining 1,2,4-trichlorobenzene used in functional fluids in
1979 (i.e., 99% or 1,356) was contained within the apparatus, isolated
from the environment. However, these capacitors and transformers
periodically rupture, leak and/or become obsolete and must be discarded.
If the.quantity of 1,2,4-trichlorobenzene incorporated into electrical
apparatus in 1979 is assumed to be equal to the amount released that
year by the disposal of apparatus manufactured prior to 1979, then
1,356 kkg would have been lost to the environment. Furthermore, it is
assumed that all of this 1,2,4-trichlorobenzene is disposed of on
land.
3.3.4 Miscellaneous Uses
The miscellaneous uses of 1,2,4-trichlorobenzene comprised only 7%
of the total quantity of 1,2,4-trichlorobenzene domestically consumed
in 1979 and totalled about 530 kkg (Figure 3-1). These uses include:
degreasing agents (424 kkg), septic tank and drain cleaner formulations
(53 kkg) wood preservatives (53 kkg), and abrasive formulations (<5 kkg).
3.3.4.1 Degreasing Agents
An estimated 424 kkg of 1,2,4-trichlorobenzene were used in degreasing
agents in 1979, of which, 382 kkg were used for stripping electronic wafers
(see Notes 6 and 22, Appendix A for details). Based on EPA emission rates
and waste solvent recovery values, an estimated total of 286 kkg of 1,2,4-
trichlorobenzene were released to the environment from wafer stripping as
follows: 190 kkg were emitted to the atmosphere, 67 kkg disposed of on land
and 29 kkg discharged to POTWS (see Table 3-3 for details).
3-13
-------
Table 3-3. Estimated Quantities of 1,2,4-Trichlorobenzene in Metric Tons (kkg) Released to the
Environment During Electronic Wafer Degreasing Operations3
Quantity Consumed Quantity Recycled Estimated Environmental Releases.
Hater Land Air
Surface P~ST¥.
382 86 29 67 190
a) Approximately 50% (191 kkg) of the total Quantity consumed (382 kkg) becomes contaminated with inpurities
during operation where 45% (86 kkg), 35% (67 kkg), 15% (29 kkg) and 5% (10 kkg) of this waste solvent is
reclaimed and recycled, disposed to landfill and plant grounds, discharged to POTWs, and destroyed by
incineration, respectively; the remaining 50% (191 kkg) is emitted to the atmosphere (see footnote b);
numbers may not add due to rounding.
b) Based on 430 g solvent emitted per kilogram of solvent consumed (+30% with an average of 164 kkg) it is
assumed all of the 1,2,4-trichlorobenzene carried out by the parts during processing (26 kkg) is emitted
to air.
Source: EPA, 1979c.
-------
Approximately 42 kkg of 1,2,4-trichlorobenzene were incorporated
into a degreasing agent formulation used to clean automotive engines
(see Appendix A, Note 6 for calculations). Losses of this isomer were
most likely to the atmosphere and probably can be attributed to evapor-
ation of the cleaning compound during mixing and handling. Therefore
all of the 1,2,4-trichlorobenzene contained in formulations used to
clean automotive engines (42 kkg) was assumed to be emitted to the
atmosphere (Figure 3-1).
3.3.4.2 Septic Tank and Drain Cleaners
In 1979, 53 kkg of 1,2,4-trichlorobenzene were used in septic tank
and drain cleaners (Figure 3-1, Hull and Co. 1980, see Appendix A,
Note 6 for calculations). If one assumes that one-half of the 1,2,4-
trichlorobenzene used in. these products was contained in septic tank
cleaners and one-half was contained in drain cleaners, then 27 kkg of
1,2,4-trichlorobenzene were disposed of on land and 27 kkg were dis-
charged to municipal waters as these products were used.
3.3.4.3 Wood Preservatives
In 1979, 53 kkg of 1,2,4-trichlorobenzene were used in a special
formulation used to preserve wood (see Appendix A, Note 6 for calcula-
tions) . According to Hull (1980), this formulation is injected into
standing wood buildings to preserve the wood and can act as an insecti-
cide. If 1% of the 1,2,4-trichlorobenzene is lost to the atmosphere
during mixing, handling, and injection, then <1 kkg would have been
emitted to air, while the remaining 52 kkg would have been retained
in the wood".
3.3.4.4 Abrasive Formulations
A minor application of 1,2,4-trichlorobenzene, probably accounting
for <5 kkg in 1979, is its use as a wetting and bonding agent in the manu-
facture of abrasive grinding wheels (Richards 1980, Hull and Co. 1980,
see Appendix A, Note 6 for calculations and Note 23 for manufacturing
details). Most of the 1,2,4-trichlorobenzene vaporizes during wheel
curing operations so that less than 0.3% by weight of the grinding wheel
is 1,2,4-trichlorobenzene and grinding wheel use would not release
significant amounts of the compound (Richards 1980, Hull and Co. 1980).
Thus, nearly all of the 1,2,4-trichlorobenzene used in grinding wheel
manufacture, (<5 kkg) is emitted to the atmosphere during formulation,
mixing, and curing (Richards 1980).
3.4 MUNICIPAL DISPOSAL OF 1,2,4-TRICHLORQBENZENE
This section deals with the ultimate disposal of 1,2,4-trichloro-
benzene to municipal waste facilities. These include: publicly-
owned treatment works (POTWs) and urban refuse disposal.
3-15
-------
3.4.1 PQTWs
Input of 1,2,4-trichlorobenzene to POTWs is largely dependent upon
variations in industrial discharges feeding the POTWs and the types of
industry in the particular municipal area.
An overall materials balance for 1,2,4-trichlorobenzene in POTWs,
presented in Table 3-4, can be constructed using a total POTW flow of
approximately 10H I/day and a mean concentration of <1 ug/1 in influent
and <2 yg/1 in effluent (EPA 1979d, 1980c). If influent and effluent
flow rates are assumed to be equal (i.e., water loss from sludge removal
and evaporation are small compared with influent flows) , then 73 kkg of
1,2,4-trichlorobenzene would have been discharged from POTWs. However,
because significantly larger quantities of 1,2,4-trichlorobenzene are
known to have been released from the textile industry alone, the dis-
charges of 1,2,4-trichlorobenzene from POTWs could be considerably
higher (Garrison and Hill 1972, Simmons et al. 1977, EPA 1980b).
The quantity of 1,2,4-trichlorobenzene discharged in sludge can be
estimated from the concentration in sludge and the quantity of dry sludge
produced annually [5.5 x 10& kkg (EPA 1980 c)]. If the average 1,2,4-
trichlorobenzene concentration of wet sludge is assumed to be 25 ug/1
(see Table 3-4), wet sludge is assumed to be 95% water by weight, and
1 liter of sludge is assumed to weigh 1 kg, approximately 3 kkg of
1,2,4-trichlorobenzene were discharged as sludge (which was probably
disposed of on land).
3.4.2 Urban Refuse
Urban refuse is handled by three methods: (1) energy recovery
(primarily by incineration), (2) material recovery and (3) disposal
through incineration or landfills. Urban refuse can be divided into
two major components: a combustible fraction (e.g., papers, plastics,
fabrics, etc.) and a noncombustible fraction (e.g., ferrous and non-
ferrous metals, glass, ceramics, etc.). Although specific data concerning
the release of 1,2,4-trichlorobenzene from municipal incinerators could
not be found, incineration of chlorotoluene- and chlorobenzene-containing
wastes results in a destruction efficiency of greater than 99.9%
(MacDonald et al. 1977). Therefore, it is most likely that 1,2,4-tri-
chlorobenzene-containing wastes, once combusted, are likewise not a
significant source of 1,2,4- trichlorobenzene releases to the environ-
ment.
Nearly 1,360 kkg of 1,2,4-trichlorobenzene are assumed to have been
contained in dielectric liquids within electrical apparatus disposed of
in urban refuse. It is assumed that the amount of 1,2,4-trichlorobenzene
consumed annually in dielectric fluids equals the amount contained in
equipment discarded annually; these fluids are then released to land as
a result of corrosion and rupture. On the basis of these assumptions,
1360 kkg of 1,2,4-trichlorobenzene are released from this source each
year.
3-16
-------
Table 3-4. 1,2,4-Trichlorobenzene Distribution in POTW Influent, Effluent and Sludge Samples from Select Urban Sites
Plant
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
% Industrial
Contribution
30
<5
10
7
10
38
15
10
10
5
18
50
33
25
25
16
25
50
20
15-22
Average Flow
(I/day)
3970
340
390
3120
980
260
1890
850
1800
1140
1550
1480
640
510
190
5300
370
3100
2650
3790
Concentrations (ng/1)
Influent Effluent Combined Sludge
0 <10 <10
< 10 <10 23
1 <5
<5 <5 272^
14 <5 158C
a) Historical flowrate; percentage of flow contributed by industrial sources ranges from
-------
REFERENCES
Balba, M.H; Saha, J.G. Metabolism of lindane - C1^ by wheac
plants grown from treated seed. Environmental Letters. 7:181-194;
1974.
Beck, J; Hansen, K.E. The degradation of quintozene, pentachloro-
benzene, hexachlorobenzene, and pentachloroaniline in soil. Pesticide
Science. 5:41-48;1974.
Bellar, T.A.; Lichtenberrg, J.J.; Kroner, R.C. The occurrence of
organohalides in chlorinated drinking waters. Journal American Water
Works Association. December, 1974, p. 703.
Comer, R.; Chen, A; Lee, A. (JRB Associates, Inc.) Trichlorobenzene
and tetrachlorobenzene, 1979.
Davis, M.B. (Vice President, Standard Chlorine of Delaware, Inc.).
Personal Communication, October, 1980.
Dickson, B. (Dow Chemical Company, lawyer for chlorinated benzenes).
Personal Communication, October, 1980.
Dittmar, H.R. Ethyl Corporation, assignee. U.S. patent 2,749,372.
1956 June 5.
Dow Chemical Company. Comments on the third report of the Toxic
Substances Control Act interagency testing committee. Washington,
DC.: U.S. EPA, 1979; OTS-040005.
Environmental Protection Agency, 1975a. Assessment of hazardous
wastes practices, organic chemicals, pesticides, explosives
industries. Washington, DC: EPA/530/SW-118C;1975.
Environmental Protection Agency, 1975b. Survey of Industrial
Processing Data, Task I - Hexachlorobenzene and Hexachlorobutadiene
Pollution from Chlorocarbon Processing. Washington, DC: EPA/560/3-
75-00351975.
Environmental Protection Agency, 1976. Chlorinated Compounds Found in
Waste-Treatment Effluents and Their Capacity to Bioaccumulate.
Washington, DC: EPA-600/J-76-027;1976.
Environmental Protection Agency, 1977a. Investigation of Selected
Potential Environmental Contaminants: Halogenated Benzenes. EPA-
560/2-77-004;1977.
3-18
-------
Environmental Protection Agency, 1977b. The National Organic
Monitoring Survey, Office of Water Supply. Washington, DC; 1979.
Environmental Protection Agency, 1977c. OAQPS Guidelines. Control of
Volatile Organic Emissions from Solvent Metal Cleaning. Research
Triangle Park, NC: EPA-450/2-77-022;1977.
Environmental Protection Agency, 1978a. Source Assessment:
Chlorinated Hydrocarbons Manufacture. Washington, DC: EPA-600/2-78-
004;1978.
Environmental Protection Agency, 1978b. Chlorolysis Applied to the
Conversion of Chlorocarbon Residues. Research Triangle Park, NC:
EPA-600/2-78-146;1978.
Environmental Protection Agency, 1979a. Status Assessment of Toxic
Chemicals, Hexachlorobenzene. Cincinnati, OH: EPA-600/2-79-210g;
1979.
Environmental Protection Agency, 1979b. Development Document for
Effluent Limitation Guidelines and Standards for the Textile Mills,
Point Source Category. Washington, DC: EPA-440/l-79/022b;1979.
Environmental Protection Agency, 1979c. Source Assessment - Solvent
Evaporation - Degreasing Operations. Cincinnati, OH:
EPA-600/2-79-019f; 1979.
Environmental Protection Agency, 1979d. Comprehensive Sludge Study
Relevant to Section 8002(g) of the Resource Conservation and Recovery
Act of 1976. Washington, DC: SW-802;1979.
Environmental Protection Agency, 1980a. Materials Balance for
Chlorobenzenes. Office of Toxic Substances. Washington, DC:
EPA-560/13-80-001;1980.
Environmental Protection Agency, 1980b. Assessment of Testing Needs:
Chlorinated Benzenes, Support Document for Proposed Health Effects
Test Rule Toxic Substances Control Act, Section 4. TSCA Chemical
Assessment Series. Office of Pesticides and Toxic Substances.
Washington, DC: EPA-560/11-80-014;1980.
Environmental Protection Agency, 1980c. Fate of Priority Pollutants
in Publicly Owned Treatment Works, Interim Report. Washington, DC:
EPA-440/1-80/301;1980.
Garrison, A.W. and S.W. Hill. Organic Pollutants from mill persist in
downstream waters. American Dystuff Reporter, Feb.: 21-25;1972.
3-19
-------
Hardie, D.W.F. Chlorinated Benzenes. In Kirk-Othmer Encyclopedia of
Chemical Technology, 2nd Ed. New York: John Wiley and Sons;
5:253-267;1964.
Harris, M. Foreign Trade Division, U.S. Department of Commerce.
Personal Communication, October 1980.
Hull, R. (Hull and Co.) Personal Communication, 1980.
Hull and Co. Employee Exposure to Trichlorobenzene Products, prepared
for The Chlorobenzene Producers' Association, October 22, 1980.
Johnson, R.D.; Manske, D.C. Pesticides in food and feed. Pesticides
Monitoring Journal. 11(3):116-131;1977.
Karapally, J.C.; Sana, J.G.; Lee, Y.W. Metabolism of lindane -
C ^ in the rabbit: ether-soluble urinary metabolites. Journal of
Agriculture and Food Chemistry. 21(5):811-818.
i
Lapp, J.; Saddler, F.S. McGraw-Edison Co., assignee. U.S. patent
3,966,505. 1976.
Lewis, P.F. Chlorinated Benzenes. Department of Health, Education
and Welfare, Public Health Service, Division of Chemical Technology,
Rockville, MD., January 1975.
Lombards, P. FDA's Chemical Contaminants Program: The Search for the
Unrecognized Pollutant. Annual New York Academy of Science, 320:
673-677;1979.
Lowenheim, F.A., and M.K. Moran. Faith, Keyes, and Clark's Industrial
Chemicals, Fourth Edition, Wiley-Interscience, New York, 1975.
MacDonald, L.P.; Skinner, D.J.; Hopton, F.J.; Thomas, G.H. Burning
Waste Chlorinaed Hydrocarbons in a Cement Kiln. Canada: Environ-
mental Protection Service, Fisheries and Environment.
EPS-4-WP-77-2;1977.
Mathur, S.P; Saha, J.G. Microbial degradation of lindane-C^ in a
flooded sandy loam soil. Soil Science. 12(4):301-307;1975.
Menzie, C.M. Metabolism of Pesticides. Washington, DC: U.S.
Department of the Interior, Fish and Wildlife Service. 1969.
Morrison, R.T; Boyd, R.N. Organic Chemistry, 2nd Ed., 1970. Allynand
Bacon, Inc.: Boston, Massachusetts.
Nipp, G. (Plant Manager, Hooker Chemical Company, Plant Manager.
Personal Communication, October 1980.
3-20
-------
OPTS, 1979. Computer printout: Production Statistics for Chemicals
in the Nonconfidential Initial TSCA Inventory, Washington, DC:
Environmental Protection Agency, Office Pesticides and Toxic
Substances.
Phillips, D.D.; Word, L.F.Jr. Shell Oil Co., assignee. U.S. patent
3,102,842. 1963, September 3.
Richards, Tom. (Norton Company) Personal Communication, November
1980.
Richter, S.B. Velsicol Chemical Corporation, assignee. U.S. patent
3,013,054. 1961 December 12.
Simmons, P.O.; Branson, D.; Bailey, R. 1,2,4-Trichlorobenzene:
biodegradable or not? Textile Chemical Color. 9(9):211-213;1977.
Sittig, M. Pesticides Process Encyclopedia, Noyes Data Corporation,
Park Ridge, New Jersey, 1977.
Standford Research Institute, Chemical Economics Handbook, Product
Review: Chlorobenzenes, March 1980.
Tu, C.M. Utilization and degradation of lindane by soil
microorganisms. Archives of Microbiology. 108:259-263;1976.
United States International Trade Commission (USITC), 1980.
3-21
-------
4.0 FATE AND DISTRIBUTION IN THE ENVIRONMENT
4.1 INTRODUCTION
This chapter identifies the environmental pathways of 1,2,4-trichloro-
benzene resulting from its release into the environment. Four major sources
of release of the chemical in 1979 identified in Chapter 3.0 are illustrated
in Figure 4-1. The textiles industry, utilizing 1,2,4-trichlorobenzene
as a dye carrier, is the largest consumer and largest source of release .
of the chemical. Most of the releases from the textile industry are to
publicly owned treatment works (POTWs). This industry is the only iden-
tified direct discharger of 1,2,4-trichlorobenzene to surface water, and
releases 1,2,4-trichlorobenzene to air and land as well. Other signif-
icant sources of 1,2,4-trichlorobenzene release to the environment include
the disposal of used electrical apparatus; primary 1,2,4-trichlorobenzene
production; and production of pesticides, herbicides and functional fluids.
The remainder of this chapter describes the fate of 1,2,4-trichloro-
benzene following its release to the environment as it is transformed or
transported in environmental media. The fate of 1,2,4-trichlorobenzene in
the aquatic environment is discussed in Section 4.3. The ultimate fate of
the chemical in ambient surface waters and drinking waters is identified
and quantified to the degree possible. Output from the EXAMS model is
used to support and amplify laboratory studies regarding the aquatic
fate of 1,2,4-trichlorobenzene. Section 4.4 discusses atmospheric fate.
Only 12% of all identified environmental releases of 1,2,4-trichloroben-
zene are to the air and the compound is not believed to persist.as a
result of photodegradation or wet and dry deposition. Terrestrial fate
is discussed in Section 4.5, including possible sinks for 1,2,4-trichloro-
benzene deposited on land, such as groundwater, accumulation by microbial
organisms, and soil particles (through adsorbtion). Finally, the fate
of 1,2,4-trichlorobenzene in treated waters is explored in Section 4.6.
Of particular concern here are the efficiencies of POTWs, the likelihood
of formation of 1,2,4-trichlorobenzene from chlorination of waste and
drinking waters, and occurrence of 1,2,4-trichlorobenzene.
Throughout this chapter, the available data for laboratory and field
studies are discussed as appropriate. Where they are available, monitoring
data are presented to provide an accurate picture of actual environmental
conditions to which humans and other receptors may be exposed.
4.2 PHYSICOCHEMICAL PROPERTIES
Table 4-1 lists physical and chemical properties for 1,2,4-trichloro-
benzene. Three trichlorobenzene isomers (1,3,5-; 1,2,3-; 1,2,4-) are
commercially produced in the U.S. During the chlorination of benzene,
orientation effects direct the chlorines to attach to certain positions
on the benzene ring such that 1,2,4-trichlorobenzene is the predominant
trichlorobenzene isomer formed (ca. 85-90%). Some commercial mixtures
4-1
-------
SOURCE OF RELEASE
PERCENTAGE OF TOTAL RELEASE PER MEDIUM
RECEIVING
MEDIA
PERCENTAGE OF
TOTAL RELEASES
-P-
N>
DISCARDED
ELECTRICAL
APPARATUS
FIGURE 4-1 ENVIRONMENTAL RELEASES OF 1.2.4 TRICHLOROBENZENE
Source: Arthur D. Little, Inc.
-------
TABLE 4-1. PHYSICAL AND CHEMICAL PROPERTIES OF
1,2,4-TRICHLOROBENZENE
Molecular Weight:
Structure:
Melting Point:
Boiling Point:
Water Solubility:
i
Specific Gravity at 25/25°C:
Log Octanol/Water Partition Coefficient:
Vapor Pressure at 25°C:
Cl
16.95°C (62.5°F)
213.5°C (416.3°F)
30 mg/1 (at 25°C)
1.454
4.27
0.42 mm Hg (torr.)
Source: Morrison and Boyd (1978).
4-3
-------
sold as "trichlorobenzene" are known to contain approximately 85% 1,2,4-
trlchlorofaenzene; the other isomers are present in the proportions in
which they occur during production (Hardie 1964, Morrison and Boyd 1973).
The chemical and physical behavior of the three isomers is very similar.
Trichlorobenzene is a very stable organic molecule, because the halogen-
ation of benzene deactivates the ring to electrophilic substitution. Aryl
halides are also highly unreactive to nucleophilic substitution (Morrison
and Boyd 1973). Thus chemical degradation not mediated by biological"
processes is not likely to be an important fate pathway for 1,2,4-tri-
chlorobenzene.
4.3 AQUATIC FATE
4.3.1 Introduction
As discussed in Chapter 3.0, releases to surface water are a major
point of entry into the environment for 1,2,4-trichlorobenzene. The
single most important use of 1,2,4-trichlorobenzene is in the dyeing and
textile industry. The 1,2,4- isomer of trichlorobenzene has been found
in the effluent wastewaters of these industries at concentrations ranging
from 0.1 yg/1 to 1 mg/1 (Hites 1973, Gaffrey 1976 and 1977).
From 25% to 30% of the 1,2,4-trichlorobenzene produced is used in
insecticide and herbicide preparations. Some is used in aquatic herbi-
cides; that used in other insecticides/herbicides is likely to contam-
inate runoff. These combined contributions would result in an occurrence
of 1,2,4-trichlorobenzene in surface water that is not associated with
industrial activity.
This section characterizes the fate processes that transform or
transport 1,2,4-trichlorobenzene in surface water and determine the ulti-
mate distribution in the environment. Monitoring data are analyzed to
determine the levels of 1,2,4-trichlorobenzene in effluents associated
with municipal wastewater systems, and the textile and other industries
with 1,2,4-trichlorobenzene contaminated wastes. The fate processes
associated with 1,2,4-trichlorobenzene in water are identified and dis-
cussed theoretically and on the basis of EXAMS modeling results. Concen-
trations of 1,2,4-trichlorobenzene detected in ambient waters and aquatic
organisms are reported.
4.3.2 Concentrations in Effluents to Surface Waters
Concentrations of 1,2,4-trichlorobenzene in industrial effluents
discharged to surface water are reported in the STORET Water Quality
System maintained by the U.S. EPA (U.S. EPA 1980a). All concentrations
currently recorded in STORET are remarked data, that is, are below
established detection limits but are above zero. There were 588 observa-
tions throughout the U.S. as shown in Table 4-2. These were frequently
low, with 72% indicating concentrations belwo 10 yg/1. Approximately
28% of the observed concentrations were between 10 yg/1 and 100 yg/1,
with the highest concentrations in the Ohio River and Upper Mississippi
River basins. There was only one observation greater than 1000 yg/1
4-4
-------
TABLE 4-2. DISTRIBUTION OF REMARKED EFFLUENT 1,2,4-TRICHLOROBENZENE CONCENTRATIONS
FOR MAJOR RIVER BASINS IN THE UNITED STATES—STORET, 1980
Concentrations (pg/1)
Major River Basin
Northeast
North Atlantic
Southeast
Tennessee River
Ohio River
Lake Erie
Upper Mississippi
Lake Michigan
Missouri River
Lower Mississippi
Colorado River
Western Gulf
Pacific Northwest
California
Great Basin
Puerto Rico
Virgin Islands
Lake Superior
Unlabelled
UNITED STATES
Number of
Observations^
147
72
97
18
76
6
71
1
26
11
5
7
39
9
1
1
1
588
j<10.0 10.1-100 100.1-999.9 >1000
118
72
95
18
17
6
8
1
17
11
4
7
38
8
1
1
1
20
1 1
59
63
9
1
1
1
423
164
Source: STORET Water Quality Control Information System, retreived on October 28, 1980.
Note: Remarked are all values between 0 and the detection limits.
-------
and this was reported for the Southeast River basin (U.S. EPA 1980a).
The mean recorded effluent observation is 12 ug/1 and the maximum is
2500 ug/1-
Concentrations of 1,2,4-trichlorobenzene in municipal wastewater,
industrial and urban runoff effluents were reported at several locations
in the U.S. during different seasons of the year as shown in Table 4-3
and Table 4-4. These ranged from less than 0.01 ug/1 in the fall to 275
ug/1 in the summer. One industrial discharge sampled in the spring in
Chattanooga, Tennessee contained 500 ug/1 1,2,4-trichlorobenzene.
Generally, where summer and fall values were reported for the same site,
the levels of 1,2,4-trichlorobenzene were twice to 20 times as high in
the summer as in the fall.
In recent sampling of industrial effluents, 1,2,4-trichlorobenzene
was detected in effluents from the textile industry, steam electric
power plants, and the non-ferrous metals industry (U.S. EPA 1980d).
As shown in Table 4-5, these concentrations range from means of 1
Ug/1 to 410 ug/1 and maxima of 260 ug/1 to 2700 ug/1 for raw waste-
water. Treated waste effluents range from 4.4 ug/1 to 610 ug/1 on the
average to maxima of 47 ug/1 to 1500 ug/1.
It is clear from these data that levels of 1,2,4-trichlorobenzene
were well above ambient levels at isolated discharge points associated
with industries producing (intentionally or inadvertently) or using
1,2,4-trichlorobenzene.
4.3.3. Fate Processes^
4.3.3.1 Volatilization
Mathematical models and laboratory studies have shown that a
significant fraction of the 1,2,4-trichlorobenzene released to surface
water may be volatilized to the atmosphere in a matter of hours (Mackay
and Leinonen 1975, Garrison and Hill 1972). Other authors have suggested
that suspended microbiota can reduce the rate of volatilization (Garrison
and Hill 1972).
Several mathematical models have been developed for estimating
the rate of volatilization of organic pollutants from surface waters.
These models typically treat such volatilization as a first-order
process. The volatilization rates produced by each of the various
models correlate fairly well with the experimentally observed rates
(Appendix 0. A common approach was developed (Appendix C) to com-
pute volatilization rates. Parameters such as the wind velocity,
the water current velocity, the depth of the water body, and the
molecular weight of the chemical of interest are used with ^
Henry's Law constant (the ratio of vapor pressure to water solubility)
to calculate an overall mass-transfer coefficient. From this, the
volatilization rate constant and half-life for volatilization can be
calculated.
4-6
-------
TABLE 4-3. SEASONAL LEVELS OF 1,2,4-TRICHLOROBENZENE IN SELECTED .
EFFLUENT WATERS
Locat ion
Catawba Creek, NC
Chattanooga Creek, TN
Joint Water Pollution
Control Plant (JWPCP)
Hyperion Sewage Treatment
Works, LA (HSTW)
HSTW, LA
Orange County Sewage
Department, CA (.OCSD)
Port Loma Sewage Treat-
ment Plant, CA (PI.STP)
Oxnard, CA Sewage
Treatment Plant (OSTP)
Seasonal Mean Detected (pg/1)
Source
Industrial discharge
Industrial discharge
Municipal wastewater
5-mile effluent, municipal
wastewater
7-mile effluent, municipal
wastewater
Municipal wastewater
Municipal wastewater
Municipal wastewater
Summer
12
6.0
6.7
275
0.30
0.23
0.9
Fall
a
1.8
3.1
130
Winter
<0.01
0.25
Spring
500
Source: U.S. EPA (1980b).
- Indicates that no samples were taken.
-------
TABLE 4-4. OBSERVATIONS OF 1,2,4-TRICHLOROBENZENE
LEVELS IN WASTEWATERS
Source/Location
Delaware River at
Philadelphia, PA:
Effluent, unidentified
chemical plant A
Treatment plant
influent incl. A
Treatment plant
effluent to river
2-4 miles upstream
of treatment plant
discharge
Concentration
(ug/1) References
200
20
10
"trace"
Sheldon and Hites (1979)
Influent to a municipal
wastewater treatment
plant adjacent to the
Ohio River (.no date)
66.9
Bellar et al. (1974)
4-8
-------
TABLE 4-5. CONCENTRATIONS OF 1,2,4-TRICHLOROBENZENE IN WASTE STREAMS
OF INDUSTRIAL SOURCES TO WATER
Source
Raw Waste Streams
Textile Mills
Steam Electric Plants
Foundries
Non-Ferrous Metals
Concentrations (ug/1)
Minimum Maximum
Mean
n.a.
n.a.
n.d.
n.d.
2700
n.a
n.a
266
410
10
7
22
Treated Waste Streams
Textile Mills
Foundries
Non-Ferrous Metals
n.a.
<20.0
n.d.
1500
570
47
610
290
4.4
Note: n.a.: not available
n.d.: not detected
Source: U.S. EPA (1980d)
4-9
-------
For a hypothetical unpolluted stream 1 m deep, moving at 6 m per
second, with a wind speed of 5 m per second (fairly typical conditions),
the half-life for volatilization of 1,2,4-trichlorobenzene calculated by
this model is 5.8 hours. Since about 95% of the "resistance" to volatil-
ization is in the liquid phase (Mackay and Leinonen 1975), parameters
such as stream depth and stream flow velocity greatly affect the rate
of volatilization.
Laboratory studies suggest that volatilization rates are similar
although slightly more rapid than those determined from mathematical
models. Ninety percent of the 1,2,4-trichlorobenzene volatilized in
less than 4 hours from an aerated, distilled water sample originally
containing 100 mg/1 of 1,2,4-trichlorobenzene. This corresponds to a
volatilization half-life of about 0.5 hour (Garrison and Hill 1972).
The volatilization half-life increases to about 7.2 hours when the
distilled water sample is not aerated.
The latter observation suggests that under conditions most favorable
to volatilization, 1,2,4-trichlorobenzene may be volatilized quickly
due to its short half-life of 1 hour or less. Under quiescent conditions,
the volatilization half-life process decreases considerably, on the
order of several hours.
The presence of organic sediment and biomass is expected to decrease
the rate of volatilization. The relatively large octanol/water parti-
tion coefficient (4.26) for 1,2,4-trichlorobenzene indicates that the
chemical will partition into the lipid (fat-containing) fractions of
biota. Absorbtion by biota removes 1,2,4-trichlorobenzene from the
body of water and hence the quantity available for volatilization
decreases. When a sample with an initial concentration of 50 mg/1 of
1,2,4-trichlorobenzene and "mixed cultures of aerobic microorganisms"
was aerated, although 90% of the concentration was lost by 24 hours,
low levels of the chemical persisted for up to 9 days (Garrison and
Hill 1972). When this is compared with the 0.5 hour half-life for
complete volatilization from aerated distilled water containing only
the 1,2,4-trichlorobenzene, it becomes clear that although volatilization
must still be considered an important environmental pathway for 1,2,4-
trichlorobenzene, the presence of microorganisms reduces volatilization
apparently by biodegradation and/or absorption. No information was
given on the experimental procedures to determine whether the two
studies are directly comparable." Additionally, the presence of other
absorbing material, i.e., organic matter, was not measured to determine
its role in adsorption of the chemical.
4.3.3.2 Bioaccumulation
Trichlorobenzene is known to bioaccumulate in fish tissue. Labo-
ratory studies indicate a rapid initial build-up in tissue. Rainbow
4-10
-------
trout had a bioconcentration factor of 100 above water levels at 8 hours
and 400 at 4 days in muscle tissue. Partial biotransformation of the
compound occurred in the fish as indicated by transformation products
in the muscle and liver (Melancon e_t al. 1979). In field studies,
however, tissue levels of sampled fish are generally low, on the
order of 10 ug/kg or less (Young and Heesen 1977, Ofstad
-------
[The EXAMS and other computer model results best define how 1,2,4-
trichlorobenzene partitions between these media (see Section 4.3.4).]
That which is adsorbed by sediment is expected to be slowly degraded
by the microorganisms associated with particulates or, in the case of
the anaerobic layer of bottom sediment, may persist for longer periods
of time.
4.3.3.5 Chemical Degradation
Processes such as hydrolysis, photolysis, and oxidation are not
likely to occur to any significant extent for 1,2,4-trichlorobenzene
in surface water. As mentioned earlier, the trichlorobenzene molecule
is inherently stable in all types of chemical reactions. It is unlikely
that 1,2,4-trichlorobenzene will hydrolyze in ambient water due to the
extreme difficulty with which aryl halides undergo nucleophilic sub-
stitution. Although no specific data were readily available on the
oxidation of 1,2,4-trichlorobenzene, the compound is reportedly sus-
ceptible to attack by hydroxyl radicals in the atmosphere (Callahan
et_ aL. 1979). Although the high energy of ambient ultraviolet radiation
can degrade the trichlorobenzene molecule, such photolysis has been
shown not to occur with 1,2,4-trichlorobenzene in water (Akermak 1978).
4.3.4 Modeling of Environmental Distribution
For the purpose of estimating the potential fate of 1,2,4-trichloro-
benzene in various generalized aquatic environments under conditions of
continuous discharge, the EXAMS (Exposure Assessment Modeling System)
model AETOX 1 was implemented (U.S. EPA 1980c). The physical-chemical
properties and reaction rate constants used as input parameters are
listed in Table 4-6. An arbitrary loading rate of 1.0 kg/hr was chosen
as realistic under occasional circumstances in the environment and used
to compare the compound's fate in different aquatic systems: a pond,
oligotrophic lake, eutrophic lake, average river, turbid river, and
coastal plain river. The simulated systems represent "average" U.S.
water bodies. Their characteristics (i.e., biomass, sediment concen-
trations, climatic conditions) are described in the model output (U.S.
EPA 1980c) but only flow, length, and depth are given in Table 4-7 for
the purposes of brevity.
Tables 4-8 and 4-9 present the output of the EXAMS simulations by
ecosystem type. Presented are average concentrations at equilibrium
in various media (water, sediment, biota, etc.) and percent loss due
to different fate processes.
According to the EXAMS results, the most significant removal pro-
cess for trichlorobenzene was volatilization. In the low-flow, physically
static systems — the pond and lakes — volatilization accounted for more
than 90% of the chemical's loss, resulting in a system clearance time
(assuming cessation of discharge after equilibrium is attained) of 6.5 to
19 months. The lower amount of sediment and biomass in the oligotrophic as
4-12
-------
TABLE 4-6. PARAMETERS FOR 1,2,4-TRICHLOROBENZENE USED
IN EXAMS ANALYSIS
Property
Molecular Weight
Solubility
Liquid Phase Transport
Resistance
Henry's Law Coefficient
Vapor Pressure
Partition Coefficient:
• Biomass/Water
• Sediment/Water
• Octanol/Water
Chemical Oxidation Rate
• Water >
• Sediment
Biodegradation Rate
• Water
• Sediment
Value3
181.45 g/mole
30 mg/1
0.456
2.31x10 m3 atm/mole
0.29 torr
3070
1.02x10
4 mg/kg
mg/1
1 mole/1/hr
360 mole/1/hr
IxlO"10 mole/1/hr
lxlO~10 mole/1/hr
All data from SRI (1980).
4-13
-------
TABLE 4-7. FLOW AND DEPTH OF EXAMS SIMULATED SYSTEMS'
Depth (m)
System
Pond
Eutrophic Lake
Oligotrophic Lake
River
Turbid River
Water Flow
(m3/day)
0.643
4.1xl05
4.1xl05(b)
2.4xl07
2.4xl07
2.4xl06
Water
Column
2
20 (c)
20 (c)
3
3
3
Sediment
0.05
0.05
0.05
0.05
0.05
0.05
Sediment Mass
in Water
Column (kg)
600
2695
525
6x10*
3xlOf
6000
(c)
(c)
Length (i
NA
NA
NA
3
3
3
aAll data from U.S. EPA (1980c) output.
bAverage flow for littoral zone, epilimnion and hypolimnion.
clncludes epilimnion and hypolimnion (deepest part of lake).
4-14
-------
TABLE 4-8. STEADY-STATE CONCENTRATIONS IN VARIOUS GENERALIZED AQUATIC SYSTEMS
RESULTING FROM CONTINUOUS 1,2,4-TRICHLOROBENZENE DISCHARGE AT 1.0 kg/hra
Maximum Concentrations
*-
System
Pond
Eutrophic
Lake
Oligotrophic
Lake
River
Turbid
River
Coastal Plain
River
Loading
1.0kg hr""1
1.0kg hr"1
1.0kg hr'1
1.0kg hr"1
1.0kg hr-1
1.0kg hr~l
Water
Dissolved
(mg/1)
1.5
0.14
0.15
9.7xlO~A
9xlO~4
9.3xlO~3
Water
Total
(mg/1)
1.6
0.16
0.17
IxlO'3
IxlO'3
9.6xlO"3
Bottom
Sediment
(mg/1)
1.5
0.11
3.2xlO~2
2.2xlO~A
4.5xlO~A
2.8xlO'3
Maximum in
Sed imen t
Deposits Plankton
(mg/kg) (HR/B)
1.6xl03 4.7xl03
44 4.3xl02
7.1 4.6xl02
0.15 3
9.2xlO~2 2.8
4.2 29
Total Steady-
Benthos State Accumulation
(jig/g) (kg)
4.7xl03 l.lxlO3
3.4xl02 IxlO3
97 5.3xl02
0.68 3.1
1.4 2.4
8.5 66
All data simulated by EXAMS model (see text for further information).
-------
TABLE 4-9. THE FATE OF 1,2.4-TRICHLOROBENZENE IN VARIOUS GENERALIZED AQUATIC SYSTEMS*
% Residing in
Water at Steady-
System State 1
Pond
Eutrophic
Lake
Oligotrophic
Lake
River d
Turbid
3
38
83.2
30
37.4
% Residing in
Sediment at
Steady-State
97
62
16.8
70
62.6
Z Transformed
by Chemical
Processes
0
0
0
0
0
Z Transformed
by Biological
Processes
0.05
2.2_
0
0
0
X Lost
2 Volatil- by other fa
ized Processes
91.2
92.8
94.2
1.3
1.2
8.7
5
5.8
98.7
98.8
Time for
System Self-
Purification0
579 days
472 days
195 days
62 days
49 days
River u
Coastal Plain
River d
12.5
87.5
0.3
12.1
87.9
87 days
All data simulated by the EXAMS model (see text for further information).
^Including loss through physical transport out of system.
cEstimate for removal of Ca 75% of the toxicant accumulated in system. Estimated from the results of the half-lives
for the toxicant in bottom sediment and water columns, with overall cleansing time weighted according to the toxicant's
initial distribution.
All river systems are 3 km in length so that physical transport out of the modelled system is dominant loss process.
The "river" system was extended to various lengths up to 1000km from the source to determine the significance of
other fate processes (see text).
-------
compared with that in the pond and eutrophic lake was responsible for
the shorter purification time due to a smaller amount of the chemical
being^adsorbed. As would be expected, under equilibrium conditions
62-97% of the 1,2,4-trichlorobenzene mass resided in the sediment, while
sediment adsorption accounted for less than 17% of the mass in the oligo-
trophic lake. Chemical oxidation of 1,2,4-trichlorobenzene was negligible
in all systems. Only in the biologically active eutrophic system was
biodegradation responsible for a noticeable loss,' albeit still less than
3% of the total mass.
In the river ecosystems, physical transport out of the model's 3-km
long box was more significant than in the other systems. From 62 to 87%
of the 1,2,4-trichlorobenzene mass in a river stretch resided in the
sediment. Chemical and biological processes were insignificant. Volatil-
ization did not become an important factor in 1,2,4-trichlorobenzene
loss until 50 km downstream from the source of release, at which point
it accounted for approximately 45% of the trichlorobenzene loss. More
than 95% of trichlorobenzene was volatilized at a distance of 500 km
downstream.
The average concentration of 1,2,4-trichlorobenzene (total) in water
was approximately 1 mg/1 in the pond and lakes and approximately 1-10 yg/1
in the rivers. Concentrations were higher in the higher biomass coastal
plain river. Levels in bottom sediment were generally two to three
orders of magnitude above water concentrations, with biomass concentra-
tions usually three orders of magnitude greater still. The significance
of biomass as a reservoir for 1.2,4-trichlorobenzene (note biomass/water
partition coefficient of 3 x 103 in Table 4-10), is reflected in the
higher values for total steady-state accumulation in eutrophic than
oligotrophic lake and coastal plain than other river systems. (Biota
and sediment may both be significant as described more fully in Section
4.1.3.5.)
Based on the output of the EXAMS simulation and depending on the
model assumptions and reliability of input variables, the following con-
clusions can be drawn about 1,2,4-trichlorobenzene's potential environ-
mental fate in aquatic systems. Persistence is a function of volatiliza-
tion. The half-lives of 1,2,4-trichlorobenzene (under conditions of con-
tinuous discharge) are listed in Table 4-10. The half-lives for the other
river systems modeled are not included because only 3-km lengths were
simulated, so that physical export was responsible for over 85% of removal.
Persistence would be greater in the coastal plain river due to higher
biomass. Since volatilization is so important in all systems, then con-
ditions of high temperatures, high wind velocity, turbulence, and low biomass
would increase the transfer of trichlorobenzene to the atmosphere in real
systems. This assumes negligible transformation of the compound in both
liquid and vapor form. The rate of biodegradation may be greater and
more competitive with volatilization under realistic environmental con-
ditions - especially conditions conducive to acclimation - than the rate
of 1 x 10--W mole/1/hr used as input.
4-17
-------
TABLE 4-10. SYSTEM HALF-LIVES FOR 1,2,4-TRICHLOROBENZENE PERSISTENCE
System tl/2'
Oligotrophic Lake 15 days
Eutrophic Lake 29 days
Pond 65 days
River 7 daysa
aln a 500-km stretch of river.
Source: U.S. EPA (1980c)
4-18
-------
.4.3.5 Concentrations Detected in Ambient Surface Waters
The STORE! Water Quality System is the principal data source for
1,2,4-trichlorobenzene in ambient waters (U.S. EPA 1980a). As is the
case with effluent concentrations (Section 4.3.2), all STORET observa-
tions for ambient water are remarked data. There were 310 observations
of 1,2,4-trichlorobenzene in ambient waters in various sections of the
U.S., as shown in Table 4-11. Approximately 86% of the observed concen-
trations were lower than 10 yg/1. In five major river basins, there were
observations between 10 yg/1 and 100 yg/1, accounting for roughly 11% of
the total. Most observations within this range occurred in the California
basin. In the Missouri River basin, eight observations were reported in
the range of 100 ug/l-to 1000 yg/1. From just over 300 observations
recorded (remarked) for the compound in the ambient water, the mean is
calculated to be 22.7 yg/1, the maximum concentration 1000 yg/1.
Fischer and Slemrova (1978) studied the pollution of surface waters
with chlorobenzene by taking a longitudinal concentration profile of
the Rhine River in Germany. The concentration of trichlorobenzene was
nearly constant in the middle segment of the river, being less than
100 ng/1. In the lower segment of the river, however, the concentration
increased to 500 ng/1.
Kites (1973) examined water samples from the Merrimack River in
New England downstream of industrial sites and five urban areas. Tri-
chlorobenzene was identified at concentrations of 0.1-0.5 yg/1, along
with other compounds commonly used in the textile industry (which was
represented in the area).
Grob and Grob (1974) analyzed various water samples in the area of
Zurich. Trichlorobenzene registered at 6 ng/1 in surface water and at
42 ng/1 from a depth of 30 m. A concentration of 4 ng/1 was recorded
for trichlorobenzene in tap water samples; the compound was not detected
in spring and groundwaters.
Selected data on concentrations of 1,2,4-trichlorobenzene observed
in ambient waters in the U.S. are summarized in Table 4-12.
4-3.6 Ambient Concentrations Reported in Other Aquatic Systems
Results from STORET (U.S. EPA 1980a) indicate the following:
• Concentrations in estuaries of the Gulf Coast and San
Francisco Bay areas are reported as less than 10 ug/1.
• Concentrations were not detected in well waters of Kansas,
Washington, Arizona and six southern states; detection limits
ranged from 1 to 50 yg/1.
4-19
-------
TABLE 4-11.
DISTRIBUTION OF REMARKED AMBIENT 1,2,4-TRICHLOROBENZENE CONCENTRATIONS
FOR MAJOR RIVER BASINS IN THE UNITED STATES— STORET, 1980
N>
O
Northeast
North Atlantic
Southeast
Tennessee River
Ohio River
Lake Erie
Upper Mississippi
Lake Michigan
Missouri River
Lower Mississippi
Colorado River
Western Gulf
Pacific Northwest
California
Great Basin
Puerto Rico
Virgin Islands
Lake Superior
Unlabelled
UNITED STATES
Number of
Observations
6
75
54
12
43
9
3
15
86
100
1
1
1
310
% at Concentration (ug/1)
1000
23
3
100
1
130
8
Source: STORET Water Quality Control Information System, retrieved on October 28, 1980.
Note: Remarked are all values between 0 and the detection limits.
-------
TABLE 4-12. AMBIENT SURFACE WATER CONCENTRATIONS
OF 1,2,4-TRICHLOROBENZENE
Source/Location
Los Angeles River
Urban Runoff (Winter)
Concentration
(yg/D
0.007
Reference
Young et al. (1976)
Merrimack River, downstream
of Concord and Manchester,
NH, and Lowell, Lawrence
and Haverhill, MA: samples
taken April 1972 and January
1973
0.1-0.5
Hites (1973)
Delaware River at Philadelphia 0.5-1.0
March 1977. None detected in
samples taken in August 1976
Sheldon and Hites (1978)
4-21
-------
• Analysis of 108 sediment samples taken in the southern
and western regions of the U.S. yielded remarked concen-
trations less than reporting limits.
4.4 ATMOSPHERIC FATE
No information was found regarding the atmospheric releases by users
of 1,2,4-trichlorobenzene. Herbicide and pesticide use of the chemical
may constitute a significant atmospheric release and may be important
in terms of human exposure.
4.4.1 Photodegradat ion
In the atmosphere 1,2,4-trichlorobenzene is apparently photodegraded
fairly rapidly. This rate appears to be rapid enough to prevent accumu-
lation (Simmons et al. 1977). Experimental studies suggest that several
mechanisms for the photodegradation of 1,2,4-trichlorobenzene exist, but _
it is difficult to extrapolate the laboratory reaction rates to rates
expected in the environment.
The most rapid photodegradative mechanism for 1,2,4-trichlorobenzene
seems to be attack by the hydroxyl radical. Hydroxyl radicals are
believed to be formed by a series of photochemical reactions involving
No, N02, other atmospheric hydrocarbons, and HC>2 (Calvert 1976). Specific
investigations of this mechanism with respect to 1,2,4-trichlorobenzene
have not been widely reported. Billing e£ al. (1976) observed that
43% of the monochlorobenzene disappeared in 7.5 hours from an initial
concentration (10 ppm) (molar basis') under simulated atmospheric condi-
tions. If this is extrapolated to 50% disappearance and corrected for
ambient light intensity, the estimated half-life for the atmospheric
photodecomposition of monochlorobenzene is 23 hours. A variety of sub-
stituted benzenes (not including any chlorobenzenes) were determined
by Darnall et al. (1976) to belong to a class of compounds that have
atmospheric half-lives between 0.24 and 24 hours.
Photodechlorination is a possible mechanism for atmospheric degrada-
tion of 1,2,4-trichlorobenzene (Akermark et al. 1976, and Akermark 1978)..
Irradiation by ultraviolet light in the 300-nm range (as is found in
the atmosphere) results in the removal of a chlorine atom from the
1,2,4-trichlorobenzene, which is replaced by a hydrogen atom from the
solvent. In the experiments performed by Akermark, 2-propanol^was the
hydrogen-donating solvent. Although Akermark observed that 20% of the
initial quantity of 1,2,4-trichlorobenzene was dechlorinated (to dichloro-
benzene) in 70 minutes, it is difficult to extrapolate this rate to a
expected rate under atmospheric conditions, particularly because of the
low natural abundance of the required hydrogen donors in the atmosphere.
Although Akermark states that, "Prolonged irradiation of [1,2,4-tri-
chlorobenzene] will ultimately lead to complete dehalogenation," (Akermark
1978), the rate at which the initially-formed dichlorobenzenes will
be dechlorinated further is unknown. Photodechlorination, then, may
be an important atmospheric degradative pathway, but its contribution
cannot be quantified.
4-22
-------
Photoformation of polychlorinated biphenyls from 1,2,4-trichloro-
benzene (and from other chlorinated benzenes) was observed by Uyeta
et al. (1976). Although this reaction is not likely to account for
very much 1,2,4-trichlorobenzene in the atmosphere, it may be of
interest due to the nature of the products. Twenty grams of a chloro-
benzene in a sealed glass flask were exposed to the sun for 56 days.
Under these conditions, 1,2,4-trichlorobenzene produced the greatest
quantity of PCBs compared with any of the other nine chlorobenzenes
studied. The 1,2,4-trichlorobenzene flask contained 5,710 mg/1 of
PCBs after 14 days of irradiation, and after 56 days of irradiation,
the concentration of PCBs in the flask was nearly 17%. This reaction
consists of two interacting chlorobenzene molecules. The conditions
of pure undiluted chlorobenzene, which produced the large amounts of
PCBs noted above, highly favor PC3 production more than the normal
atmospheric conditions in which part-per-billion or part-per-trillion
levels of 1,2,4-trichlorobenzene occur. For this reason, atmospheric
production of PCBs from 1,2,4-trichlorobenzene does not seem likely
to account for a significant portion of the fate of 1,2,4-trichloro-
benzene in the atmosphere.
4.4.2 Wet and Dry Deposition
Ten measurements of the dry deposition of 1,2,4-trichlorobenzene
at five locations in southern California were made during the fall of
1975 and the spring of 1976 (Young et al. 1976). The largest median .
value reported was <20 ng/m2 per day from six collections at one loca-
tion during the fall of 1975. The median value of all ten observations
is reported as <11 ng/m2 per day. Due to the low atmospheric concen-
trations of 1,2,4-trichlorobenzene, it is not expected that wet or dry
deposition is a significant pathway for 1,2,4-trichlorobenzene.
4.4.3 Atmospheric Monitoring
The non-point releases dispersed throughout the United States com-
bined with rapid atmospheric dilution, probably preclude the detection
of 1,2,4-trichlorobenzene by ordinary analytic methods. The few reports
of observed concentrations indicate extremely low ambient 1,2,4-trichloro-
benzene concentrations in the atmosphere. At 16 sites around the U.S.,
air monitoring data indicate levels of 1,2,4-trichlorobenzene below the
detection limits (ranging from 10 ng/nP to 100 ng/m3). The only excep-
tions were at several monitoring sites specifically chosen in the vicinity
of chemical industry facility around which there were known to be atmos-
pheric concentrations of various chemical compounds. At several of these
chemical plants and dump sites, 1,2,4-trichlorobenzene was observed,
however, these concentrations were all below 167 yg/m^ and are not
assumed to be representative of ambient concentrations (Pellizzari
1978).
4-23
-------
4.5 TERRESTRIAL FATE
4.5.1 Introduction
A large portion (some 36%) of the estimated environmental releases
of 1,2,4-trichlorobenzene are to land (see Chapter 3.0). The primary
source of land release is disposal of used electrical equipment con-
taining 1,2,4-trichlorobenzene bearing fluids. Other sources include
use of pesticides and herbicides containing 1,2,4-trichlorobenzene, and
disposal of treated sludge from various industries. Consequently, the
land is a significant pathway for 1,2,4-trichlorobenzene. The available
data on the fate of the compound on land are insufficient for a full
evaluation of this pathway, however, within the constraints of the data,
the following topics are discussed: adsorption by soil, volatilization,
biodegradation and leaching to groundwater.
4.5.2 Adsorption on^o Soil
Though some portion of the 1,2,4-trichlorobenzene in soil will be
adsorbed onto the soil particles, this phenomenon will compete with
volatilization and biodegradation. The Freundlich equation yields a
value of 22 mg adsorbed 1,2,4-trichlorobenzene per kilogram of soil
[assuming a soil absorption coefficient of 11,000, a soil organic
content of 2% and a 1,2,4-trichlorofaenzene concentration of 0.1 mg/1
in the water above the soil (Fiksel and Segal 1980)]. The material
that is adsorbed by soil either persists in the soil or is biodegraded.
Volatilization is a competing force in the moist portion of the
soil column. The strength of this force is dependent upon temperature,
the extent of aeration, and the presence of microbial organisms. (Vola-
tilization is more fully discussed in Section 4.3.3.1.)
4.5.3 Biodegradation
The two most important biological processes with respect to 1,2,4-
trichlorobenzene are biodegradation, which "removes" the compound through
transformation to other substances; and bioaccumulation, which stores
the compound temporarily and may or may not be concurrent with metabolism
of the substance. Bioaccumulation is discussed in Section 4.3.3.2 and
biodegradation is discussed below.
There is laboratory evidence that trichlorobenzene is degraded under
aerobic conditions. Table 4-13 presents the results of several biode-
gradation studies on the compound. In general, the studies produce
similar results and indicate a rapid, initial spurt of biodegradation
within the first few days. Some metabolic intermediates apparently
build-up and the break-down of these, as well as the degradation of
the remainder of the initial trichlorobenzene, occurs at a rate slower
than the initial rate. None of the studies were allowed to proceed
long enough to determine the period of time needed for ultimate degra-
dation of 1,2,4-trichlorobenzene to C02, H20, and minerals.
4-24
-------
TABLE 4-13. MICROBIAL BIODEGRADATION OF 1,2,4-TRICHLOROBENZENE
Microbial
Population
Source and Type
Sandy loam soil,
unacclimated,
aerobi c
Soil in liquid
culture, unaccli-
mated
Type of Study
Closed flask
Shake flask
Results
Source
Degradation rate 1.0 n mol./day (per 20 gm. soil) Marinucci and
Bartha (1979)
Degradation rate 7.3+ 0.6 n mol./day
Marinucci and
Bartha (1979)
N>
Ul
Sewage sludge
in liquid cul-
ture, unacclimated
and acclimated
Wastewuter
population
uiiacc I imated
Static flask
BOD bottles
Tested at 5 and 10 mg/1, first in unacclimated
culture, then in 3 successive subcultures each
seeded with the preceeding culture. Table below
presents percent degraded in 7 days.
Cone. Unacclimated
(mg/1)
5 54%
10 43%
Subcultures
70%
54%
59%
14%
24%
0
55% degraded in 10 days (based on TOD decline).
Tabak et al.
(1980)
Simmons et al,
(1977)
Wastewater
popuJation
unacclimated
14C02 evolution
in aerated closed
flasks
1) 33% of trichlorobenzene was converted to C02
in one day, 56% in 5 days. Maximum degradation
rate was 40 mg/gMLVS/day.
2) Mass balance of trichlorobenzene at 120 hrs.
was 56% converted to C02, 7% volatilized, 23% to
polar metabolites, 13% remaining as trichlorobenzene.
Simmons et al
(1977)
-------
Little attempt has been made to identify the degradation products
of 1,2,4-trichlorobenzene. Figure 4-2 presents a proposed partial
degradation pathway determined by C^-labeling (Marinucci and Bartha
1979). Identifiable intermediate products included 2,4-, 3,5-, and 3,4-
dichlorophenol and 3,5-dichlorocathechol.
Since trichlorobenzene is volatile, soil with high organic content
would tend to reduce losses through volatilization and retain the com-
pound longer; the opportunity for biodegradation would be longer in such
soils. Additional organic matter in Marinucci and Bartha's (1979) soil
experiment had no impact on the rate of biodegradation itself.
4.5.4 Soil to Groundwater; A Field Study
The U.S. EPA (1976) described an accidental spill of 1,500 gal of
transformer fluid, which contained a mixture of chlorinated organics
including 1,2,4-trichlorobenzene and other chlorobenzenes. Soil and
groundwater monitoring data in the areas around the spill revealed that
the trichlorobenzene component of the solvent migrated quickly out of
the spill area, through the soil, and into the local groundwater supplies.
The higher chlorinated benzenes were observed to be retained preferen-
tially in the soil around the spill areas and migrated much more slowly
than the trichlorobenzenes. A 236-ft well adjacent to the spill areas
showed "solvent" concentrations of 1 ug/1 in the groundwater 2 years
after.the spill, compared with an initial groundwater concentration of
500 ug/1.
The presence of detectable concentrations of solvent observed .2 years
after the spill might suggest that soil degradation is very slow, but
it must be noted that an unusually large amount of solvent was spilled.
4.6 FATE IN POTWs AND OTHER WATER TREATMENT FACILITIES
4.6.1 Wastewaters
Removal efficiencies ranging from 13% to 100% have been reported
for 1,2,4-trichlorobenzene in POTWs and water treatment plants. Specific
observations of 1,2,4-trichlorobenzene concentrations in influent and
effluent are listed in Table 4-14.
Simmons et al. (1977) performed laboratory biodegradation experi-
ments using radiolabeled 1,2,4-trichlorobenzene and activated sludge
from an industrial secondary wastewater plant. The results (see Table
4-13) indicated rapid biodegradation in the first day and 50% degrada-
tion by 5 days; the experiment did not continue long enough to determine
the fate of the remaining intermediate metabolic products which were
not degraded to C02 during the study period. The study suggests
that biological treatment can be an effective removal process for
4-26
-------
Unknown
(V)
Unknown
Ring Cleavage
I 1,2,4-trichlorobenzene
II 2,4-dichlorophenol
III 3,5-dichlorocatechol
IV 2,5-dichlorophenol
V 3,4-dichlorophenol
Source: Marinucci and Bartha (1979).
FIGURE 4-2 PROPOSED BIODEGRADATION PATHWAY
FOR 1,2.4-TRICHLOROBENZENE
4-27
-------
TABLE 4-14. TRICHLOROBENZENE REMOVAL EFFICIENCIES OF SELECTED
WASTEWATER TREATMENT FACILITIES3
Sample Source
Sewage treatment plant/ Ohio
River.
Concentration(ug/1)
Influent Effluent References
Wastewater treatment plants
handling industrial effluents in
Philadelphia, Pennsylvania
Northeast Sewage Treatment Plant
handling industrial effluents in
Philadelphia, Pennsylvania.
66.9
60
1
9
43
20
57.9
0
1
1
13
10
Bellar et al. (1974)
Gaffney (1976)
Sheldon and Hites (1979.)
Unspecified isomer.
4-28
-------
1,2,4-trichlorobenzene in wastewater treatment. Another result of the
study was that after 5 days, only 7% of the original quantity of 1,2,4-
trichlorobenzene had volatilized. Throughout the experiment, about 80%
of the 1,2,4-trichlorobenzene present was associated with sludge solids,
which slowed down the rate of volatilization.
Wroniewicz (1978) described a wastewater treatment study in which
biological treatment was among several alternatives investigated. Bio-
logical treatment was determined "unsuitable" as a wastewater treatment
alternative due to the necessity for very long retention times and the
accumulation of organics in the sludge. Treatment with activated car-
bon was found to be the best method for organics removal.
Brandon and Samfield (1978) reported on an advanced wastewater treat-
ment method which, although not commercially available at this time, has
been shown to be very effective for the removal of many types of pol-
lutants, including organic compounds with molecular weights ^90. Tri-
chlorofaenzene (unspecificed isomer) at 100 mg/1 (100 ppm) is reported to
be rejected at greater than 99% by a "PA-200 poly (ether/amide) thin-
film composite membrane" at 1,000 psi and at 25°C. Brandon and Samfield
also report that the use of such filtration may be economically viable
at full scale.
During the summer and winter seasons of 1976, Heesen and Young
(1977) collected daily grab samples of final effluent from the five
largest dischargers of municipal wastewater to the Southern California
Bight. Effluent samples were analyzed using solvent extraction methods
and electron-capture gas chromatography techniques. The average con-
centrations of 1,2,4-trichlorobenzene ranged from 0.18 yg/1 to 100 yg/1
in the summer season and from 0.25 yg/1 to 43 yg/1 in the winter season
for five regions of Southern California.
Gaffney (1976) gathered information on various processing chemicals
and their concentrations in municipal wastewaters and water supplies.
The study was conducted in northwest Georgia, where a great number of
tufted textile industry plants operate in a single river basin. Water
and wastewater samples were collected during the fall and winter of
1974. At three water treatment facilities, .concentrations of trichloro-
benzene (non-isomer specific) ranged from 0.1 mg/1 to 1.1 mg/1 in raw
waters and from 0.1 mg/1 to 1 mg/1 in finished waters; concentrations in
winter samples were 0.1 mg/1 and 0.1 to 1.1 mg/1 in fall samples. These
concentrations were significantly above the detection limit of 0.2 yg/1
and appeared to increase in a downstream pattern. In wastewater samples,
trichlorobenzene concentrations ranged from 1 ug/1 to 1,297 yg/1 in
influent samples and from 0 to 13 yg/1 in final effluent samples.
In conclusion, biological treatment facilities seem to be the
most efficient at removing 1,2,4-trichlorobenzene from waste streams.
Treatment efficiencies of other systems vary from 30% to 100%.
4-29
-------
4.6.2 Effects of Chlorination During Water Treatment
Under certain laboratory conditions, 1,2,4-trichlorobenzene is
formed during the chlorination of wastewater. In water treatment
systems, no observations were found of 1,2,4-trichlorobenzene formation
from the chlorination of drinking water.
Gaffney (1977) studied the effects of chlorination on wastewater
containing biphenyl. The concentration of 1,2,4-trichlorobenzene in
wastewater influent, when chlorinated in the presence of biphenyl,
increased from 0.9 ug/1 to 2.9 ug/1. Effluent from an industrial
wastewater treatment plant subjected to the same conditions also showed
an increase from 0.3 ug/1 to 1.0 ug/1. Gaffney noted that the concen-
trations of biphenyl and chlorine used in his experiments "were compar-
able to those which may be encountered in normal operation of wastewater
treatment facilities in the area under investigation."
Glaze and Henderson (1975) obtained effluent samples before
chlorination from a Texas sewage treatment plant. These samples were
filtered and then chlorinated by bubbling chlorine gas through stirring
aliquots for 1 hour. After this intense chlorination treatment, tri-
chlorofaenzene was identified qualitatively by mass spectrometry, but
the concentration was below the level necessary for quantification.
Bellar ot_ al. (1974) studied the formation of organohalides during
the chlorination process at a treatment facility near the Ohio River.
Trichlorobenzenes were among the seven organochlorine compounds in water
from a sewage treatment facility that serves a large industrial area
and a municipality. A concentration of 66.9 ug/1 was recorded for
trichlorobenzenes in influent before treatment. Trichlorobenzenes in
effluent samples registered at 56.7 ug/1 before chlorination and
increased slightly to 56.9 ug/1 after chlorination.
Thus it appears that small amounts of 1,2,4-trichlorobenzene may
be formed during chlorination of certain wastewaters. It is likely that
the formation of 1,2,4-trichlorobenzene is dependent upon the presence of
specific precursors, such as biphenyl. If this is true, the formation
of 1,2,4-trichlorobenzene may b-e less likely to occur during the chlori-
nation of drinking water where -the water is fairly clean and free of
organics.
4.6.3 Concentrations Detected in Drinking Water
The National Organics Monitoring Survey (NOMS) conducted sampling
of drinking water systems in 113 communities throughout the United
States (U.S. EPA undated). The survey was conducted in three phases
over a 12-month period and sampled water supplies for various organics,
including 1,2,4-trichlorobenzene; these supplies represented different
types of sources and treatment processes. The detections of 1,2,4-
trichlorobenzene found in the survey are presented in Table 4-15. The
compound was only detected in 11 of the 113 cities surveyed. The most
4-30
-------
TABLE 4-15. OCCURRENCE OP 1,2,4-TRICHLOROBENZENE IN COMMUNITY
DRINKING WATER SUPPLIES
Concentration (uR/1)
i
OJ
Community
Cape Girardeau, MO
Chicago, IL
Erie, PA
Huntington, WV
Jacksonville, FL
Louisville, KY
Passaic Valley, NJ
Richmond, VA
Santa Fe, NM
Boston, MA
Toledo, Oil
Mean, Standard Deviation
Note:
Source: U.S. EPA (undated).
Phase I
March-April
1976
(112 Supplies Sampled)
10.0
Phase II
May-July
1976
(113 Supplies Sampled)
0.006
0.58
Phase III
November 1976-
January 1977
(110 Supplies Sampled)
0.03
0.01
0.01
0.03
n.d.5
0.53
0.03
0.23
0.01
0.01
0.01
0.09 + 0.1687
-------
frequent occurrence was in Phase III (November 1976 through January
1977), in which 1,2,4-trichlorofaenzene was found in waters from 10 com-
munities at concentrations ranging from 0.01 ug/1 to 0.53 ug/1 with a
mean of 0.09 ug/1. In Cape Girardeau, MO, 1,2,4-trichlorobenzene was
also detected once during Phase I (March-April, 1976) at an elevated
concentration of 10.0 ug/1. It was also detected in Jacksonville, FL
and Louisville, KY during Phase II (May-July 1976) at 0.006 ug/1 and
0.58 ug/1, respectively.
Sheldon and Hites (1978) identified roughly 100 organic compounds
in Delaware River water samples collected in August 1976 and March
1977 between Marcus Hook, PA and Trenton, NJ. This segment of the
river was selected because it is a direct source of drinking water
for several cities in the region and is the most heavily industrialized
area along the river. The concentration range for trichlorobenzene
was 0.5 ug/1 to 1 ug/1 in the winter; trichlorobenzenes were not
detected during the summer.
The transport of industrial organic chemicals from their source in
the Delaware River, via various treatment facilities and into Philadel-
phia's drinking water supply was investigated by Sheldon and Hites (1979)
The segment of the Delaware River examined flows through a heavily
industrialized area and is dominated by tidal movement as opposed to
downstream river flow. These conditions allow industrial chemicals to
be transported from sewer outfall upstream to the intake pipe of a
drinking water facility. Several compounds appeared to originate at a
number of plants in the area; the concentration of trichlorobenzenes
at.one plant site registered at 200 ug/1 though the plant may not be
the sole contributor of trichlorobenzenes in the river system. At
a sewage treatment plant downstream, trichlorobenzenes registered at
20 ug/1 in influent samples and at 10 yg/1 in final effluent samples.
At two sampling points before the drinking water facility, only trace
amounts of trichlorobenzenes were detected. In both influent and
effluent samples at the drinking water treatment facility, as well as
downstream from the facility, none of the trichlorobenzene isomers were
detected.
Coleman et al._ (1980) used the closed-loop-stripping technique to
examine the effect of a granular activated carbon filter on the removal
of organic compounds in drinking water. The granular activated-carbon
filter was implemented at a treatment facility. The 1,2,4-trichloro-
benzene isomer was recorded at 8 ng/1 in influent samples. After
the initial use of the filter (allowing 1 million gallons of water to
pass through the filter) 1,2,4-trichlorobenzene was not detected in
the effluent. After a month had elapsed with the same filter in place,
1,2,4-trichlorobenzene was not detected in the effluent samples; it
had been registered at 5 ng/1 in influent samples.
4-32
-------
4.7 SUMMARY
The compound 1,2,4-trichlorobenzene is released to all of the environ-
mental media, with land and the aquatic environment the largest receptors.
The resulting pathways are illustrated in Figure 4-3.
The inherent stability of 1,2,4-trichlorobenzene allows it to per-
sist for a long time in the soil before its ultimate degradation. With
the exception of biomagnification, this persistence has associated
with it the effect of greatly diluting the chemical before it is
degraded. This dilution, along with the relatively small usage of
1,2,4-trichlorobenzene, precludes good observations of these ultimate
degradation mechanisms. An exception to this may be biodegradation,
however, the potential of this is reduced by biomagnification.
Nearly 52% of the initial 1,2,4-trichlorobenzene releases are to
surface waters and POTWs, primarily by the textile-dyeing industry. A
portion of the amount released to surface water is rapidly volatilized
to the atmosphere. The magnitude of this rapid volatilization is
unknown and probably varies greatly depending upon the presence of
adsorbing matter and degree of aeration. A large portion of the 1,2,4-
trichlorobenzene will rapidly volatilize from distilled water, within
a matter of hours under aerated conditions and within a few days under
static conditions. No information was available on natural waters;
however, in surface water with a considerable amount of suspended organic
sediment and biomass, volatilization will be very slow and biological
pathways and biodegradation will become important.
Monitoring data available in the STORET Water Quality System
report all observations of 1,2,4-trichlorobenzene in ambient waters as
remarked data, that is, observed at levels below the detection limits.
The compound was observed infrequently in ambient waters throughout the
U.S. and then only in low concentrations. Higher concentrations were
found in the vicinity of industrial effluents and POTW discharges.
In biological treatment facilities with high concentrations of
suspended biota, volatilization of 1,2,4-trichlorobenzene at an initial
concentration of 345 yg/1 has been shown to be very insignificant (7%
after 5 days). Under conditions simulating a biological treatment
plant, biodegradation has effectively degraded most of the 1,2,4-
trichlorobenzene. After 5 days, 65% was converted to C02 and 32% was
converted to polar metabolites. In practice, however, total removal
efficiencies vary from 13% removal to 100% removal (variation is
likely to occur due to adsorption by biota).
Freshwater sediments are capable of adsorbing 1,2,4-trichlorobenzene
depending upon the amount of organic matter in the sediment and the con-
centration of the chemical in the water. Based on the Freundlich equa-
tion, a river containing 0.1 mg of 1,2,4-trichlorobenzene per liter
4-33
-------
Photodegrades
Fall-out
Rapidly
Volatilizes
Biode grades
Adsorbs onto
Sediment and
Microorganisms
Removed in
Sludge or
Volatilized
Biodegraded
Volatilizes
Adsorbed
onto Soil
Discharge
to Water
FIGURE 4-3 ENVIRONMENTAL PATHWAYS OF
1.2.4 - TRICHLOROBENZENE
-------
(kilogram) of water would have an associated surface sediment concen-
tration of approximately 20 mg 1,2,4-trichlorobenzene per kg of sedi-
ment. This medium is essentially a sink for some quantity of 1,2,4-
trichlorobenzene, although biodegradation does occur slowly.
Biodegradation of 1,2,4-trichlorobenzene does occur in laboratory
soil incubation studies, but it is not known if the rate of biodegrada-
tion under field conditions is fast enough to prevent the chemical from
making its way into groundwater at sites of release.
Inasmuch as 1,2,4-trichlorobenzene has never been observed in sus-
tained high concentrations in the atmosphere (even in the industrial
areas), it is likely that the amount of the chemical that is released
to the atmosphere, either from direct emissions or as a result of vola-
tilization from surface water, photodegrades at a rate which is at least
equal to the rate of release. The primary mechanism for photodegradation
appears to involve photolytically generated hydroxyl radicals. Other
mechanisms such as photochlorination and biphenyl formation also exist,
1,2,4-trichlorobenzene is rarely observed in the atmosphere. Air
samples at two chemical plants producing 1,2,4-trichlorobenzene
revealed concentrations around 100 ng/m^ infrequently.
4-35
-------
REFERENCES
Akermark, B. Photodechlorination of haloaromatic compounds. Found, G.
ed. Vol I, Dioxin: Toxicol. Chem. Aspects:191-193; 1978.
Akermark, B.; Baeckstrom, P.; Westlin, U.E.; Rolf, G.; Wachtmeister,
C.A. Photochemical dechlorination of 1,2,4-trichlorobenzene. Acta.
Chem. Scand. 830:49-52; 1976.
Bellar, T.A.; Lichtenberg, J.J.; Kroner, R.C. The occurrence of organo-
halides in chlorinated drinking waters. Journal AWWA 66:703-706; 1974.
Brandon, C.A.; Samfield, M. Application of high temperature hyper-
filtration to unit textile processes for direct recycle. Desalination
24:97-112; 1978.
Callahan, M.A.; Slimak, M.W.; Gafael, N.W. Water related environmental
fate of 129 priority pollutants. EPA 440/4-79-029a. Washington, DC:
Office of Water Planning and Standards, U.S. Environmental Protection
Agency; 1979.
Calvert, G. Hydrocarbon involvement in photochemical smog formation
in Los Angeles atmosphere. Environ. Sci. Technol. 10(3):256-262;
1976.
Coleman, W.E.; Melton, R.G.; Slater, R.W.; Kopfler, F.C. Voto, S.J.;
Allen, W.K.; Aurand, T.A. Determination of organic contaminants by
the Grob closed-loop-stripping technique. Cincinnati, OH: Office
of Research and Development, U.S. Environmental Protection Agency;
1980.
Darnall, R.; Lloyd, A.C.; Winer, A.M.; Pitts, J.N. Reactivity scale
for atmospheric hydrocarbons based on reaction with hydroxyl radical.
Environ. Sci. and Technol. 19(7):692-696; 1976.
Dilling, W.L.; Breadeweg, C.J.; Tefertiller, N.B. Organic photochem-
istry/simulated atmospheric photodecomposition rates of methylene
chloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene,
and other compounds. Environ. Sci. Technol. 19(4):351-356; 1976.
Fiksel, J.; Segal, M. An approach to prioritization of environmental
pollutants: The Action Alert System. Draft. Washington, DC: Monitoring
and Data Support Division, Office of Water Regulations and Standards,
U.S. Environmental Protection Agency; 1980.
Fischer, A.; Slemrova, J. Pollution of the Rhine with chlorobenzenes.
Vom Wasser 51:33-46; 1978.
Gaffney, E. Carpet and rug industry case study 1: water and wastewater
treatment plant operation. Journal WPCF 48(1):2590-2598; 1976.
4-36
-------
Gaffney, P.E. Chlorobiphenyls and PCB's: formation during chlorination.
Journal WPCF: 401-404; 1977.
Garrison, A.W.; Hill, D.W. Organic pollutants form mill persist in
downstream waters. American Dyestuff Reporter 2:21-25, 1972.
Glaze, W.H.; Henderson, H.E. Formation of organochlorine compounds
from the chlorination of a municipal secondary effluent. Journal WPCF
47(10):2511-2515; 1975.
Grob, K.; Grob, G. Organic substances in potable water and in its
precursor. Part II. Application in the area of Zurich. Chromatog.
90:303-313; 1974.
Hardie, D.W.F. Chlorocarbons and chlorohydrocarbons: chlorinated
benzenes. Kirk, R.E.; Othmer, D.F. eds. Encyclopedia of Chemical
Technology. Volume 5: New York, NY: Wiley and Sons; 1964, pp258-
266-.
Heesen, T.C.; Young, D.R. Halogenated hydrocarbons in wastewaters:
knowns and unknowns. Annual Report of the Coastal Water Research
Project. El _Segundo, CA: Southern California Coastal Research
Project, pp. 33-38; 1977.
Hites, -A. Analysis of trace organic compounds in New England rivers.
J. Chromatog. Sci. 11:570-574; 1973.
Lu, P.Y.; Metcalf, R.L. Environmental fate and biodegradability of
benzene derivatives as studied in a model aquatic ecosystem. Environ.
Health Persp. 10:269-284; 1975.
Macek, K.J.; Petrocelli, S.R.; Sleight, B.H. Considerations in assessing
potential for, and significance of biomagnification of chemical residues
in aquatic food chains. Proceedings of the ASTM Second Symposium on
Aquatic Toxicology: 1977 October 31-November 1, Cleveland, OH; 1977.
(As cited in Callahan et al. 1979)
Mackay, D.; Leinonen, P.J. Rate of evaporation of low-solubility con-
taminants from water bodies to atmosphere. Environ. Sci. Technol.
9(13):1178-1180; 1975.
Marinucci, A.C.; Bartha, R. Biodegradation of 1,2,3- and 1,2,4-trichloro-
benzene in soil and liquid enrichment culture. Appl. Environ. Microbiol.
9:811-817; 1979.
Melancon, M.J.; Branson, D.R.; Lech, J.J. The uptake, elimination and
metabolism of 1,2,4-trichlorobenzene in rainbow trout. Toxicol. Appl.
Pharmacol. 48(1):A170; 1979.
4-37
-------
Morrison, R.J.; Boyd, R.N. Organic chemistry. Boston, MA: Allan
and Baron; 1973.
Ofstad, E.B.; Lunde, G.; Martinsen, K.; Rygg, B. Chlorinated aromatic
hydrocarbons in fish from an area polluted by industrial effluents.
Sci. Total Environ. 10(3):219-230; 1978.
Pellizzari, E.D. Quantification of chlorinated hydrocarbons in pre-
viously collected air samples. EPA 450/3-78-112, Washington, DC: U.S.
Environmental Protection Agency; 1978.
Sheldon, L.S.; Hites, R.A. Organic compounds in the Delaware River.
Environ. Sci. Technol. 12(10):1188-1194; 1978.
Sheldon, L.S.; Hites, R.A. Sources and movement of organic chemicals
in the Delaware River. Environ. Sci. Technol. 13(5):574-579; 1979.
Simmons, P.; Branson, D.; Bailey, R. 1,2,4-trichlorobenzene: biode-
gradable or not? Textile Chemist and Colorist 9(9):211-213; 1977.
Stanford Research Institute (SRI). Estimates of physical-chemical
properties of organic priority pollutants. Preliminary draft.
Washington, DC: Monitoring and Data Support Division, U.S. Environ-
mental Protection Agency; 1980.
Tabak, H.H.; Quaves, A.; Mashni, C.I.; Barth, E.F. Biodegradability
studies with priority pollutant organic compounds. Cincinnati, OH:
Environmental Research Laboratory, U.S. Environmental Protection
Agency; 1980.
U.S. Environmental Protection Agency (U.S. EPA). National Organic
Monitoring Survey (NOMS). Washington, DC: Office of Water Supply,
U.S. Environmental Protection Agency; undated.
U.S. Environmental Protection Agency (U.S. EPA). Follow-up study
of the distribution and fate of polychlorinated biphenyls and benzenes
in soil and groundwater samples after an accidental spill of trans-
former fluid. EPA-904/9-26-014. Atlanta, GA: Division of Oil and
Special Materials Control, U.S. Environmental Protection Agency; 1976.
U.S. Environmental Protection Agency (U.S. EPA) STORET. Washington,
DC: Monitoring and Data Support Division, U.S. Environmental Protection
Agency; 1980a.
U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria for chlorinated benzenes. EPA 400/5-80-023. Washington, DC:
Office of Water Regulations and Standards, U.S. Environmental Protection
Agency; 1980b.
U.S. Environmental Protection Agency (U.S. EPA). Exposure analysis
modeling system AETOX 1. Athens, GA: Environmental Systems Branch,
Environmental Research Laboratory, Office of Research and Development,
U.S. Environmental Protection Agency; 1980c.
4-38
-------
U.S. Environmental Protection Agency (U.S. EPA). National Pollutant
Discharge Elimination System (NPDES) - Availability of wastewater
treatment manual (Treatability manual). Washington, DC: Office of
Research and Development, U.S. EPA; 1980d. Available from: U.S.
Government Printing Office, Washington, DC; Stock No. 055-00-00190-1.
Uyeta, M.; Taue, S.; Chikasawa, K.; Mazaki, M. Photoformation of
polychlorinated biphenyls from chlorinated benzenes. Nature 264:
583-584; 1976.
Wroniewicz, V.S. Controlling chlorinated benzene compounds in plant
waste waters. Pollution Engineering:43-44; Nov. 1978.
Young, D.R.; Heesen, T.C.; McDermott-Ehrlich, D.J. Synoptic survey of
chlorinated hydrocarbon inputs to the Southern California Bight.
Southern California Coastal Water Research Project Authority, El
Segundo, CA; 1976.
4-39
-------
5.0 EXPOSURE AND EFFECTS — HUMANS
5.1 HUMAN TOXICITY
5.1.1 Introduction
Data on the carclnogenicity, teratogenicity, mutagenicity, and
'long-term oral toxicity of 1,2,4-trichlorobenzene are generally
lacking. Thus, no reliable estimates can be made concerning the
effects of long-term exposure to low levels of this compound in
drinking water. The available data on the effects of 1,2,4-trichloro-
benzene are discussed in the following sections.
5.1.2 Metabolism and Bioaccumulation
The 1,2,4-isomer of trichlorobenzene is slowly absorbed from the
gastrointestinal tract, skin, and lungs. In mammals, the primary meta-
bolic pathway for 1,2,4-trichlorobenzene is via oxidation to phenols
(2,3,5- and 2,4,5-trichlorophenols) and subsequent conversion to the
glucuronide and sulfate conjugates; little or no catechol or mercap-
turic acid formation occurs with the trichlorinated benzenes (Williams
1959).
In rabbits, oral administration of 500 mg/kg of 1,2,4-trichloroben-
zene resulted in the urinary excretion of 42% of the dose as phenols
(2,3,5- and 2,4,5-trichlorophenols), 38% as glucuronic and ethereal
sulfate conjugates, 0.3% as 2,3,4- or 2,3,5-trichlorophenyl mercapturic
acids, and a trace amount of 3,4,6-trichlorocatechol (Williams 1959).
Jondorff and coworkers (1955) similarly reported that 38% of a 500-
mg/kg oral dose of 1,2,4-trichlorobenzene was metabolized to phenols
by rabbits and excreted in urine within 5 days of dosing. By the intra-
peritoneal route, approximately 11% of a single 60-75-mg/kg dose of 1,2,4-
trichlorobenzene administered to male rabbits was excreted as phenols
(5% as 2,4,5- and 6% as 2,3,5-trichlorophenol) in the urine by 10 days
(Kohli et. al. 1976). A half-life of 5.5 days has been estimated for
1,2,4-trichlorobenzene in the rabbit (Parke and Williams 1960).
In the rat, Smith and Tardiff (1978) noted that over 85% of either
an oral or intravenous dose — 10 mg/kg bw (body weight) — of 14C labelled
1,2,4-trichlorobenzene was excreted in the urine, with the remainder
recovered in feces. The tissue content of trichlorobenzene and metab-
olites reportedly varied little with route of administration; the highest
tissue concentrations were found in kidney, fat, liver, and plasma (values
not given). The data also suggested that 1,2,4-trichlorobenzene under-
goes extensive enterohepatic circulation in the rat.
Smith and Carlson (1979) reported that fecal excretion of 1,2,4-
trichlorobenzene in the rat was only 5-10% of urinary excretion following
oral administration of 1 mmole (180 mg)/kg/day for 7 days; urinary
excretion values were not given.
5-1
-------
In the rhesus monkey, only 30-40% of a 10-mg/kg intravenous dose
of radiolabelled 1,2,4-trichlorobenzene was excreted (time period
unspecified); elimination was principally via the urine (27-36% of the
dose), with lesser amounts in the feces. The same dose given orally
was reported to result in considerably more radioactivity in the urine.
No values were given. Blood concentrations of trichlorobenzene were also
reported to be generally lower and more persistent in monkeys than in
rats. Again, no values were given (Smith and Tardiff 1978).
Kohli and associates (1976) have proposed that 1,2,4-trichlorobenzene
is metabolized by means of an arene oxide intermediate via the NADPH-
cytochrome P-450 microsomal enzyme system; this pathway, however, has
not been demonstrated experimentally. Egyankor and Franklin (1977)
have reported that the 1,2,4-isomer enhances the hepatic mixed-function
oxidase system. The compound has also been demonstrated to be an in-
ducer of xenobiotic metabolism in rats (Carlson et_ _al. 1979, Carlson
1978, Carlson and Tardiff 1976, Smith and Carlson 1979, Ariyoshi et al.
1975a, b).
5.1.3 Human and Animal Studies
5.1.3.1 Carcinogenicity
No adequate studies have been conducted on the possible carcino-
genic effects associated with 1,2,4-trichlorobenzene exposure. Goto
et al. (1972) reported no increased incidence of hepatomas above con-
trols in 20 male ICR-JCL strain mice fed 1,2,4-trichlorobenzene at a
level of 600 mg/kg diet for 6 months. (Note: USEPA Criteria Document
incorrectly states that exposure was by inhalation.) The mice were
killed at 6 months. If one assumes that the stated dosage is given as
a weight/weight ratio, then a daily intake of 72 mg 1,2,4-trichloroben-
zene/kg bw/day can be estimated for a 25-g mouse ingesting on average
3 g diet/kg/bw/day.
This shorter-than-lifetime study is inadequate for the assessment
of carcinogenic risk.
5.1.3.2 Mutagenicity
Two mutagenicity studies utilizing the bacterium Salmonella typhim-
urium reported negative results, with or without metabolic activation
by liver microsomes, in strains TA 100, TA 1535 (base-pair mutants) and
TA 98, TA 1537, TA 1538 (frameshift mutants) for 1,2,4-trichlorobenzene
at concentrations up to 140 mg/plate (Andersen &t_ al_. 1972, Schoeny
1978, 1979).
Schoeny (1977) also points out that pretreatment of animals with
1,2,4-trichlorobenzene can influence the mutagenesis of other compounds
by its ability to induce mixed-function oxidases.
5.1.3.3 Adverse Reproductive Effects
Studies on the possible teratogenic or reproductive effects caused
by 1,2,4-trichlorobenzene exposure could not be found.
5-2
-------
5.1.3.4 Other Toxic Effects
Chronic ingestion studies conducted with 1,2,4-trichlorobenzene
could not be found. Cragg et al. (1978) and Smith e_t al. (1978) noted
no evidence of toxicity with respect to body weight changes, hematology,
clinical chemistry, cytochrome P-450 or P-448 induction, or gross path-
ology in rhesus monkeys given oral doses of 1-25 rag/kg 1,2,4-trichloro-
benzene for 120 days. Doses of 90 mg/kg or above were toxic, while doses
of 174 mg/kg were lethal within 20-30 days. At doses of 125 mg/kg,
temporary weight loss and evidence of hepatic enzyme induction was
indicated by a shift in the urinary pattern of chlorguanide metabolites
and increased clearance of intravenous doses of labelled 1,2,4-trichloro-
benzene. Animals receiving the highest dosage (174 mg/kg) exhibited
severe weight loss and fine tremors, which were most pronounced a few
days before death. Terminally, they had elevated levels of urea N, Na,
K, CPK, SCOT, SGPT, LDH, and alkaline phosphatase, as well as hypercal-
cemia and hyperphosphatemia; there was no evidence of jaundice. Non-
lethal clinical signs and biochemical changes were quickly reversed when
treatment was discontinued.
Subchronic exposure to 1,2,4-trichlorobenzene by inhalation was
studied in Sprague-Dawley rats, New Zealand white rabbits, or cynomolgus
monkeys (Macaca fascicularis) by Coate et_ _al. (1977). These authors
reported no exposure-related effects on body veight, hematology or serum
biochemical determinations including BUN, total bilirubin, SCOT, SGPT,
alkaline phosphatase, and LDH after 4, 13, or 26 weeks of inhalation
exposure to 200,400, or 800 mg/m^ 1,2,4-trichlorobenzene, 7 hours per
day,.5 days per week. In addition, no exposure-related ophthalmic
changes or detectable microscopic changes in the liver and kidneys were
observed in either rabbits or monkeys. Monkeys tested after 26 weeks
of exposure exhibited no dose-related changes in static compliance, CO
diffusion capacity, distribution of ventilation, or lung volumes. Three
indicators of operant behavior indicated no dose-related changes in mon-
keys at all tested doses after 26 weeks of exposure. Transient liver
and kidney effects were noted in rats after both 4 and 13 weeks, but had
disappeared by 26 weeks of exposure. These transient changes included
dose-dependent enlargement of individual hepatocytes, and dose-indepen-
dent increases in the degree of vacuolation of hepatocytes, slight
increases in the degree of biliary hyperplasia, hyaline degeneration in
the inner zone of the cortex of the kidney, and slight increases in
incidence and degree of granuloma formation in the livers (the latter had
disappeared by 13 weeks). Although these effects were transient in
nature, the fact that slight changes in parenchymal hepatic and renal
cells of rats were evident after only 4 weeks of intermittent exposure
to 200 mg/m^ 1,2,4-trichlorobenzene suggests a need for additional
studies.
Watanabe et_ al. (1978) reported indications of induction of hepatic
porphyria in rats following a study of inhalation by rats, dogs and
rabbits of 80, 240 or 800 mg/m3 1,2,4-trichlorobenzene, 7 hrs/day, 5 days/
week for 30 exposures. At concentrations of 240 mg/m3 and 800 mg/m3,
5-3
-------
elevated urinary excretion and uroporphyrin and coproporphyrin were
noted in rats, and both dogs and rats exhibited increased liver weights
at the 800-mg/m3 level. Inhalations of 800 mg/m3 1,2,4-trichlorobenzene,
6 hrs/day, 5 days/week for 3 months, produced slightly increased urinary
uroprophyrin excretion over 90 days in rats. This increase, however, dis-
appeared 2-4 months after exposure ceased. The no adverse effect level
in rats was 24 mg/m3. No significant effects on body weight, hematology,
or gross or microscopic pathology were demonstrated in any of the three
animal species at any dose level.
In similar studies, Rimington and Ziegler (1963) were able to induce
experimental hepatic porphyria in three male rats given 730 mg/kg bw of
1,2,4-trichlorobenzene by gavage (maximum tolerated dose) daily for 15
days. Urinary coproporphyrin excretion was increased (58.3 ug/day vs.
4.3-6.8 ug/day in controls). Urinary porphobilinogen (PBG) excretion
was also elevated (197 ug/day) above the control values (2.5-6.5 ug/day).
The porphyria could be reversed by glutathione administration. Hair
loss due to follicular hyperkeratosis was also noted.
Carlson (1977) reported increased liver weights, but no induction
of hepatic porphyria in rats following oral administration of 50, 100
or 200 mg/kg 1,2,4-trichlorobenzene daily for 30, 60, 90 or 120 days.
Increases in liver porphyrins minimally increased after 200 mg/kg for
30 or 90 days, but urinary excretion of ALA and PBG was not elevated
at any dose regardless of duration of exposure.
The compound 1,2,4-trichlorobenzene could not be considered
hepatotoxic, as judged by serum isocitrate dehydrogenase activity,
following oral administration of 150, 300 or 600 mg/kg/day to rats for
14 days. Liver glucose-6-phosphatase activity decreased with doses
of 300 mg/kg/day or greater, but were not affected at 150 mg/kg/day.
Doses of 600. mg/kg/day 1,2,4-trichlorobenzene were not lethal even
after 14 days of administration (Carlson and Tardiff 1976).
For acute exposures, Rowe (1975) reported minor eye and respiratory
irritation in humans when exposed to 24 mg/m3 or 40 mg/m3 1,2,4-
trichlorobenzene vapor but not to 19.2 mg/m .
Acute oral LD50 values of 756 (556-939) mg/kg and 766 (601-979) mg/kg
1,2,4-trichlorobenzene have been reported for rats and mice, respectively,
with deaths delayed 3-5 days after dose administration. Animals exhibited
depressed activity at sublethal doses and extensor convulsions prior to
death at lethal concentrations. (Brown et_ al. 1969). The lowest lethal
dose reported for intraperitoneal injection of 1,2,4-trichlorobenzene
in mice is 500 mg/kg (RTECS 1978).
Yamamoto et_ a^. (1978) reported dermal LD5Q values for 1,2,4-
trichlorobenzene in ddY strain mice of 300 mg/kg and 305 mg/kg (male
and female, respectively). An acute toxic percutaneous dose of 6,139
mg/kg 1,2,4-trichlorobenzene was reported for rats by Brown et al.
(1969). Irritation to the skin was minor, although fissuring typical of
5-4
-------
a defatting action was observed after prolonged contact in rabbits and
guinea pigs. Spongiosis, acanthosis, and parakeratosis were noted in
both species, along with some inflammation of the superficial dermis
in rabbits exposed daily for 3 weeks. Some guinea pigs exposed to 0.5
ml/day 1,2,4-trichlorobenzene, 5 days/week for 3 weeks exhibited necrotic
lesions of the liver and death after extensor convulsions (Brown et al.
1969).
Yang et_ al_. (1979) reported a more than 900% increase in bile-duct
pancreatic-fluid (BDPF) flow and a more than 50% reduction in its pro-
tein concentration 24 hours after intraperitoneal injection of 5 mmoles
(900 mg)/kg 1,2,4-trichlorobenzene into male Holtzman rats. BDPF chlo-
ride concentration and serumic glutamic pyruvic transaminase (SGPT)
activity were not significantly changed, but hepatic bile flow was
increased. The mechanism by which 1,2,4-trichlorobenzene increases
BDPF flow is not known, but it is not produced by secretin or cholinergic
stimulation of the pancreas; nor was liver damage essential for the in-
creased flow to occur.
5.1.4 Summary of Human Effects Considerations
5.1.4.1 Ambient Water Quality Criterion — Human Health
The position of the U.S. Environmental Protection Agency (1980)
is that there are insufficient toxicological data on the health effects
of 1,2,4-trichlorobenzene to establish a toxicological criterion for
preventing adverse effects in man.
5.1.4.2 Health Effects Considerations
The general lack of data on the carcinogenicity, teratogenicity,
mutagenicity and long-term oral toxicity of 1,2,4-trichlorobenzene (see
Table 5-1) does not allow one to estimate reliably the effects of long-
term human exposure to low levels of 1,2,4-trichlorobenzene. No data
on human exposure effects are available other than reports of eye and
respiratory irritation occurring at concentrations of 24 mg/m3 but not
at 19 mg/mj.
Animal data indicate that 1,2,4-trichlorobenzene is i,_cr«ly absorbed
from the gut, skin and lung and metabolized to phenols, probably via an "
arene oxide intermediate. The phenols, in conjugated form, are excreted,
principally via the urine.
Subchronic studies with rhesus monkeys suggested little effect on the
liver, hematological parameters, or clinical chemistries at levels of
25 mg/kg/day orally for 120 days. Signs of toxicity became evident at
90 mg/kg, with lethality occurring within 20-30 days in animals given
174 mg/kg/day.
Similar results were reported for rats, rabbits, and dogs exposed by
inhalation to concentrations up to 800 mg 1,2,4-trichlorobenzene/m3, 7 hrs/
day, 5 days/week for 30 exposures. Experimental hepatic porphyria (which is
5-5
-------
TABLE 5-1. ADVERSE EFFECTS OF 1,2,4-TRICHLOROBENZENE ON
MAMMALS AND BACTERIA
Adverse Effect
Carclnogenicity
Teratogenicity/
Reproductive
Effects
Mutagenicity
Disturbances in
hematology,
clinical chem-
istries ,; liver-
pathology
Hepatic porphyria
(reversible)
Median oral
lethal dose
Species
Salmonella
rhesus
monkey
dog
rat
rat
rat
Lowest Reported
Effect Level
No data available
No data available
No Apparent
Effect Level
90 mg/kg/day
orally
240 mg/m3, 7 hr/day
5 d/wk for 30 ex-
posures
LD50 » 756 mg/kg
140 mg/plate
25 mg/kg/day
orally for
120 days
800 mg/m3,7
hr/day, 5 d/wk
for 30 exposures
24 mg/m3, 7
hr/day, 5 d/wk
for 30 exposures
Source: Data taken from Section 5.1 of this report.
Note: These data are taken from studies that were not presented in
sufficient detail to allow extrapolation of human dose response
relationships for 1,2,4-trichlorofaenzene. These data should not
be considered as threshold human effects levels.
5-6
-------
reversible when exposure ceases) has been induced in rats given 730
mg/kg/day 1,2,4-trichlorobenzene by gavage for 15 days, but not in rats
given 200 mg/kg daily for 120 days. No other data are available.
None of this information is sufficient to estimate dose-response
relationships for humans to 1,2,4-trichlorobenzene with any degree of
reliability.
5.2 EXPOSURE
5.2.1 Introduction
As a man-made compound produced in relatively low volumes, 1,2,4-
trichlorobenzene has been found infrequently and in low concentrations
throughout the human environment. The most common route of human exposure
is by ingestion of drinking water and food. Concentrations of 1,2,4-tri-
chlorobenzene are infrequently detected in the air and then only at low
concentrations. As a result, exposure through inhalation is not expected
to be significant. There is no evidence to indicate that percutaneous
exposure occurs or is significant.
5.2.2 Exposure Routes
5.2.2.1 Exposure through Ingestion
Man may ingest 1,2,4-trichlorobenzene in drinking water or in food.
The chemical occurs in water as a result of its use in industrial pro-
cesses. The textile, industry is the largest consumer and identified
discharger of 1,2,4-trichlorobenzene in the United States to water (both
surface water and POTWs). The U.S. EPA has identified releases of 1,2,4-
trichlorobenzene from steam electric power plants, foundries, and the
non-ferrous metals industry. Concentrations of 1,2,4-trichlorobenzene
detected in the effluents associated with these industries range from 4.4
yg/1 to 2700 yg/1 as reported in Table 4-14. Because of the occurrence
of 1,2,4-trichlorobenzene in industrial discharges to POTWs and because
some treatment processes are not efficient at removal of 1,2,4-trichloro-
benzene, the chemical is found in POTW effluents. Specific sites of dis-
charge from POTWs, industries and surface runoff with effluents containing
1,2,4-trichlorobenzene were monitored in different seasons of the year
as shown in Table 4-3. Surface runoff into the Los Angeles River con-
tained 0.007 yg/1 1,2,4-trichlorobenzene in the winter; data for the other
seasons were not given. Municipal wastewaters were monitored across the
country in the summer and in the fall: typically the concentrations
were from 2 to 20 times higher in the summer (0.23 to 275 jjg/1) than in
the fall (< 0.01 to 130 yg/1). Levels of 1,2,4-trichlorobenzene in
industrial discharges in North Carolina in the summer and Tennessee in
the spring averaged 12 yg/1 and 500 yg/1, respectively.
The presence of 1,2,4-trichlorobenzene in surface waters, as iden-
tified above, suggests the possible 1,2,4-trichlorobenzene contamination
of drinking water systems and marketable fish species, which are the
principal potential contributors to human exposure through ingestion.
5-7
-------
In the Water Quality Criterion Document (U.S. EPA 1980), the highest
reported concentration of 1,2,4-trichlorobenzene in drinking water was
1.0 yg/1.
The National Organics Monitoring study (U.S. EPA und.) was conducted
in three phases throughout a one-year period. The.results with respect
to 1,2,4-trichlorobenzene are presented in Table 4-15. In the first
phase, 1,2,4-trichlorobenzene was detected once out of 112 samples at a
concentration of 10 yg/1. Typical concentrations in the other samples
were in the range of 0.006 ug/1 to 0.58 yg/1. The 10 positive samples
(greater than the detection limits) of Phase III were observed with a
median of 0.02 yg/1. The daily intake of 1,2,4-trichlorobenzene resulting
from consumption of drinking water contaminated with the highest levels
would be 1.16 to 20 yg/day, assuming an average adult water consumption
of 2.0 liters per day (ICRP 1975). Using the median value (0.02 ug/1)
the average adult would consume 0.04 yg/day.
Fish that were taken from 1,.2,4-trichlorobenzene contaminated waters
and consumed are a potential source of ingested 1,2,4-trichlorobenzene.
U.S. EPA (1980) reported that trout taken from Lake Superior and turbot
taken from Lake Huron contained measurable concentrations of trichloro-
benzene (unspecified isomer). There were no data available that iden-
tified concentrations of 1,2,4-trichlorobenzene in edible species of
fish, and consequently, the ingestion of 1,2,4-trichlorobenzene associated
with human consumption of fish cannot be evaluated,
5.2.2.2 Exposure through Inhalation
Atmospheric releases of 1,2,4-trichlorobenzene are a small portion
of total environmental releases (see Chapter 3.0). Futhermore, follow-
ing atmospheric release, it is likely that 1,2,4-trichlorobenzene is
rapidly diluted and/or photodegraded (see Chapter 4.0). Air monitoring
at 16 sites throughout the United States indicated that 1,2,4-trichloro-
benzene typically occurred below the detection limits of 10 to 100 ng/m-5.
At isolated chemical plants and in the vicinity of waste dumping sites,
1,2,4-trichlorobenzene was occasionally detected at levels of 167 ng/m3
or lower (Pellizzari et al. 1978), however those levels are not repre-
sentative of the environment. During a study of aerial dry deposition
in southern California in which 5 samples were taken, median levels of
1,2,4-trichlorobenzene were consistently less than 11 ng/m2/day (U.S.
EPA 1980)..
For the small populations in the immediate vicinity of chemical
plants or dumpsites potentially exposed to concentrations of 1,2,4-tri-
chlorobenzene, average intake by inhalation would be a maximum of 240
ng/hour during a worst-case exposure. This assumes an average adult
breathing rate of 1.4 m^/hour (ICRP 1975). Exposure to 1,2,4-trichloro-
benzene via inhalation for the general population is expected to be much
lower to the point of being insignificant.
5-8
-------
5.2.2.3 Percutaneous Exposure
The only identified source of 1,2,4-trichlorobenzene to which the
human skin is potentially exposed in the non-occupational environment
is as a result of dry deposition from the atmosphere (noted above).
In that absorption of liquid 1,2,4-trichlorobenzene is slow, no dermal
absorption via atmospheric deposition is not expected to be a significant
route.
5.2.3 Summary
Exposure to 1,2,4-trichlorobenzene does not appear to be significant
due to the low concentrations found throughout the environment. Except
in areas with industrial activity in which 1,2,4-trichlorobenzene is
found in aquatic discharges and atmospheric releases, 1,2,4-trichloro-
benzene is generally not detected. There were sufficient data available
to estimate worst-case air and drinking water exposures and these are
presented in Table 5-2. It should be noted that these estimates are
based on limited data and are not representative of widespread exposure
in the United States.
5-9
-------
TABLE 5-2. ESTIMATED EXPOSURE TO ELEVATED LEVELS OF l,2,4-TRICHLOROBENZENEa
Exposure Median Maximum Mean Maximum
Route Concentration Concentration Intake Intake
Drinking Water 0.2 \ig/lb 10.0 ug/1 0.4 Mg/dayC 20.0 M8/day°
Inhalation below 10 ng/m3 167 ng/m3 below 14 ng/hour 240 ng/hourd
a. Estimates based upon the infrequent, elevated 1,2,4-trichlorobenzene concentrations, which
were the only observations reported.
b. Median was calculated on the basis of concentrations above detection limits and is not
^ representative of all U.S. drinking water systems.
i
^j
o c. Drinking water intake assumes an average daily drinking water consumption of 2.0 liters per
day for adults.
d. Inhalation intake is based on an average adult respiratory rate of 1.4 m3/hour while awake
(ICRP 1975).
Note: These estimates are based upon limited data and not believed to represent widespread
exposure in the U.S. Information on levels of 1,2,4-trichlorobenzene in foods was
unavailable, and consequently exposure through ingestion of foods was not evaluated.
Source: Arthur D. Little, Inc. 1981.
-------
REFERENCES
Andersen, K.J.; Leighty, E.G.; Takahashi, M.T. Evaluation of herbicides
for possible mutagenic properties. J. Agric. Food Chem. 20:649-656;
1972.
Ariyoshi, T.; Ideguchi, K.; Iwasaki, K.; Arakaki, M. Relationship be-
tween chemical structure and activity. II .Influences of isomers of di-
chlorobenzene and tetrachlorobenzene on the activities of drug-metabol-
izing enzymes. Chem. Pharm. Bull. 23(4):824-830; 1975a.
Ariyoshi, T.; Ideguchi, K.; Iwasaki, K.; Arakaki, M. Relationship between
chemical structure and activity. Ill Dose-response or time-course of
induction in microsomal enzymes following treatment with 1,2,4-trichloro-
benzene. Chem. Pharm. Bull. 23(4):831-836; 1975b.
Brown, V.K.H. et al. Acute toxicity and skin irritant properties of
1,2,4-trichlorobenzene. Ann. Occup. Hyg. 12:209; 1969. (As cited by
USEPA 1980).
Carlson, G.P. Chlorinated benzene induction of hepatic porphyria. Ex-
perientia 33(12) .-1627-1629; 1977.
Carlson, G.P. Induction of cytochrome P-450 by halogenated benzenes.
Biochem. Pharmacol. 27(3):361-363; 1978.
Carlson, G.P.; Dziezak, J.D.; Johnson, K.M. Effect of halogenated ben-
zenes on acetanilide esterase, acetanilide hydroxylase and procaine es-
terase in rats. Res. Comm. Chem. Patholv Pharmacol. 25(1):181-184; 1979.
Carlson, G.P.; Tardiff, R.G. Effect of chlorinated benzenes on the
metabolism of foreign organic compounds. Toxicol. Appl. Pharmacol.
36:383-394; 1976.
Coate, W.B.; Lewis, R.; Busey, W.M.; Schoenfisch, W.H. Chronic inhala-
tion exposure of rats, rabbits, and monkeys to 1,2,4-trichlorobenzene.
Arch. Environ. Health 32(6):249-255; 1977.
Cragg, S.T.; Wolfe, G.F.; Smith, C.C. Toxicity of 1,2,4-trichloroben-
zene in rhesus monkeys: comparison of two in vivo methods for estima-
ting P-450 activity. Toxicol. Appl. Pharmacol. 45(1):340; 1978. (Ab-
stract) .
Egyankor, K.B.; Franklin, C.S. Interaction of the trichlorobenzenes
with cytochrome P-450. Biochem. Soc. Trans. 5:1519-1520; 1977.
Fishbein, L. Potential halogenated industrial carcinogenic and muta-
genic chemicals. IV. Halogenated aryl derivatives. Sci. Total Environ.
ll(3):259-278; 1979.
5-11
-------
Goto, M.; Hattori, M.; Miyagawa, T.; Enomoto, M. [Hepatoma formation
in mice after administration of high doses of hexachlorocyclohexane
isomers.] Chemosphere. 1:279-282; 1972.
International Commission on Radiological Protection (ICRP). Report of
the Task Group on Reference Man. New York, NY: Pergamon Press; 1975.
Jondorff, W.F.; Parker, D.V.; Williams, R".T. Studies in detoxification.
66. The metabolism of halobenzenes, 1,2,4- and 1,3,5-trichlorobenzene.
Biochem. J. 61:512-521; 1955. (As cited by Fishbein 1979).
Kohli, I.; Jones, D.; Safe, S. The metabolism of higher chlorinated
benzene isomers. Can. J. Biochem. 54:203-208; 1976.
Parke, D.V.; Williams, R.T. Studies in detoxification. Metabolism of
halobenzenes: (a) Penta- and hexachlorobenzene: (b) Further observations
on 1,3,5-trichlorobenzene. Biochem. J. 74:1; 1960. (As cited by USEPA
1980).
Pellizzari, E.D. Quantification of chlorinated hydrocarbons in pre-
viously collected air samples. EPA 450/3-78-112. Washington, DC:
U.S. Environmental Protection Agency; 1978.
Registry of Toxic Effects of Chemical Substances, 1978 Edition (RTECS)
Cincinnati, Ohio: U.S. Dept. of Health, Education, and Welfare, Public
Health Service, Center of Disease Control, National Institute for Oc-
cupational Safety and Health. DHEW (NIOSH) Publication No. 79-100;
1979: 187-188.
•
Rimington, C.; Zeigler, G. Experimental porphyria in rats induced by
chlorinated benzenes. Biochem. Pharmacol. 12:1387-1397; 1963.
Rowe. Written communication; April 1975. (As cited by USEPA 1980).
Schoeng, R.S. Bacterial mutagenesis and liver activation in the assess-
ment of carcinogens. Diss. Abstr. Int. B. 38(5):2036-2037; 1977. (Ab-
stract) .
Schoeng, R.S.; Loper, J.C.; Smith, C.C. Rat liver induction by repre-
sentative chlorinated hydrocarbons as determined by bacterial mutagene-
sis. Mutat. Res. 53(1):69; 1978.
Schoeng, R.S.; Smith, C.C.; Loper, J.C. Nonmutagenicity for Salmonella
of the chlorinated hydrocarbons Aroclor 1254, 1,2,4-trichlorobenzene,
mirex and kepone. Mutat. Res. 68(2): 125-132; 1979.
Smith, C.C.; Tardiff, R.G. Metabolic characteristics of 1,2,4-trichloro-
benzene. Plaa, G.L. and Duncan, W.A.M., eds. Proceedings of the first
international congress on toxicology. New York: Academic Press; 1978:
p566 (poster presentation).
5-12
-------
Smith, E.N.; Carlson, G.P. Pharmacokinetics of 1,2,4-trichlorofaenzene
and 1,2,4-trichlorobenzene. Toxicol. Appl. Pharmacol. 48(1):A153;
1979. (Abstract)
U.S. Environmental Protection Agency (U.S. EPA) National Organics
Monitoring Survey (NOMS). Washington, DC: Office of Water Supply;
U.S. EPA; undated.
U.S. Environmental Protection Agency (USEPA). Ambient Water Quality
Criteria for Chlorinated Benzenes. Report No. EPA 440/5-80-028.
Washington, D.C.: Criteria and Standards Division, Office of Water
Regulations and Standards; 1980.
Watanabe, P.G.; Kociba, R.J.; Hefner, R.E. Jr.; Yakel, H.O.; Leong, B.K.J.
Subchronic toxicity studies of 1,2,4-trichlorobenzene in experimental
animals. Toxicol. Appl. Pharmacol. 45(1)332-333; 1978. (Abstract).
Williams, R.T. The metabolism of halogenated aromatic hydrocarbons.
Detoxification mechanisms, 2nd ed. New York: John Wiley and Sons;
1959: 237-257.
Yamamoto, H.; Taniguchi, Y.; Imai, S.; Ohno, Y.; Tsubura, Y. Acute
toxicity and local irritation tests of trichlorobenzene (TCB) on DDY
mice. J. Nara. Med. Assoc. 29(4-5):569-573; 1978.
Yang, K.H.; Peterson, R.E.; Fujimoto, J.M. Increased bile-duct-pan-
creatic fluid flow in benzene and halogenated benzene-treated rats.
Toxicol. Appl. Pharmacol. 47(3):505-514; 1979. .
5-13
-------
6.0 EFFECTS AND EXPOSURE—AQUATIC BIOTA
6.1 EFFECTS ON AQUATIC BIOTA
The laboratory data concerning the acute toxicity of 1,2,4-trichloroben-
zene for aquatic species are very limited; the data concerning chronic effects
are even more limited. For all of the other chlorinated benzenes, there
are considerable data that can be used to extrapolate general trends in
toxicity and bioaccumulation. Overall, toxicity and bioconcentration
in aquatic organisms increase with increasing chlorination of the com-
pound (from monochlorobenzene), with pentachlorobenzene being the most
toxic (U.S. EPA 1980a).
Data concerning acute and chronic toxicity of 1,2,4-trichlorobenzene
are presented in Tables 6-1 and 6-2. These data are from recent compila-
tions (U.S. EPA 1978; U.S. EPA 1980b), and are believed to reflect the
extent of what is available at present.
The most sensitive species from these data are the mysid shrimp
of 0.45 mg/1) and rainbow trout (1.5 mg/1); the most resistent
is Daphnia, with an LCso of 50.2 mg/1. Chronic effects levels range
from 200 yg/1 to 700 yg/1. A bioconcentration factor of 182 has been
reported for bluegill (U.S. EPA 1978).
6.2 EXPOSURE
STORET monitoring data (Section 4.3) indicate that the majority
of observed concentrations in both ambient and effluent samples from
major U.S. river basins were less than 10 yg/1 (80% <10 yg/1 ambient;
72% < 10 yg/1 effluent). The mean ambient concentration is 22.7 yg/1;
the mean concentration in the effluents is 12 yg/1. Approximately 10
ambient observations were greater than 100 yg/1. The balance of the
effluent concentrations were from 10-100 yg/1.
Concentrations of 1,2,4-trichlorobenzene in effluents from municipal
wastewaters, industrial dischargers and urban runoff were reported in
various parts of the U.S. In one study these ranged from 0.01 yg/1 to
275 yg/1 in the summer and fall, with one discharge as high as 500 yg/1
in the spring in Tennessee (see Table 4-3). Effluents from the textile
industry, steam electric power plants, foundries, and non-ferrous metal
industry were sampled with 1,2,4-trichlorobenzene concentrations ranging
from means of 1 yg/1 to 410 yg/1 and maxima of 260 yg/1 to 2700 yg/1 in
raw waste effluents (see Table 4-5). Treated waste effluents sampled
in the same analysis ranged from 4.4 yg/1 to 610 yg/1 on the average
to maximums of 47 yg/1 to 1500 yg/1, also shown in Table 4-5. Data
simulated by EXAMS model (see Section 4.3.4) assume an environmental
loading of 1,2,4-trichlorobenzene of 1.0 kg/hr into various generalized
aquatic systems. As shown in Table 4-8, maximum concentrations in water
simulated were 1 yg/1 in the river, 160 yg/1 in eutrophic lakes, 170
yg/1 in oligotrophic lakes, and 1600 yg/1 in ponds.
6-1
-------
TABLE 6-1. ACUTE TOXICITY OF 1,2,4-TRICHLOROBENZENE FOR FRESHWATER AND SALTWATER SPECIES
o>
I
Test LC5Q
Species Method3 (mg/1)
Freshwater:
Cladoceran
(Daphnia magna) S,U 50.2
Rainbow trout
(Salmo gairdneri) FT,M 1.5
Fathead minnow
(Pimephales proroelas) FT,M 2.87
Bluegill sunfish
(Lepomis macrochirus) S,U 3.36
Alga
(Selenastrum capricornutura)
Saltwater:
Mysid shrimp
(Mysidopsis bahia) S,U 0.450
Sheepshead minnow
(Cyrpinodon variegatus) S,U 21.4
Alga
(Skeletonema constat'us)
EC5Q
(mg/1)
35.3 (chlo
26.7 (cell
8.7(96-hr,
phylla)
8.9(96-hr,
numbers)
Reference
U.S. EPA (1978)
U.S. EPA (1980b)
U.S. EPA (1980b)
U.S. EPA (1978)
U.S. EPA (1978)
U.S. EPA (1978)
U.S. EPA (1978)
S,U = static, unmeasured; Ff,M = flow through, with measured concentrations.
-------
TABLE 6-2. CHRONIC TOXICITY OF 1,2,4-TRICHLOROBENZENE FOR
FRESHWATER SPECIES
Chronic
Test Limits Value
Method3 Habitat5- (ug/1) (pg/1) Reference
Fathead minnow embryo- FW
Pimephales promelas larval
200-410 286 U.S. EPA (1978)
Fathead minnow
ELS
FW
499-995 705 U.S. EPA (1980b)
Sheepshead minnow ELS
Cyprinodon variegatus
SW
150-330 222 U.S. EPA (1978)
Early life stage.
FW » Fresh water
SW » Salt water
6-3
-------
REFERENCES
U.S. Environmental Protection Agency (U.S. EPA). In-depth studies on
health and environmental impacts of selected water pollutants. U.S.
EPA Contract No. 68-01-4646; 1978. (As cited in U.S. EPA 1980a)
U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria for chlorinated benzenes. EPA 440/5-80-028. Washington, DC:
Office of Water Regulations and Standards, Criteria and Standards
Division, U.S. EPA; 1980a.
U.S. Environmental Protection Agency (U.S. EPA). Unpublished laboratory
data. Environmental Research Laboratory - Duluth; 1980b.
6-4
-------
7.0 RISK CONSIDERATIONS
This chapter evaluates the human and non-human risk associated
with exposure to 1,2,4-trichlorobenzene based upon available effects
data and known exposure levels in the environment that were documented
in Chapter 5.0 and 6.0.
7.1 HUMAN RISK
The risk of adverse human effects due to exposure to ambient levels
of 1,2,4-trichlorobenzene through ingestion, inhalation, or percutaneous
exposure cannot be reliably evaluated at this time due to insufficient
data in two areas. First, there is a general lack of data on the car-
cinogenicity, teratogenicity, mutagenicity, and long-term oral toxicity
of 1,2,4-trichlorobenzene. Available human data are limited to reported
eye and respiratory irritation following acute exposure to 1,2,4-trichloro-
benzene. Second, since there is a general lack of data concerning levels '
of the compound in air, surface water, soil, and groundwater, it is not
possible to quantify with any degree of certainty the levels to which
humans are exposed.
7.1.1 Human Health Considerations
On the basis of the available animal data on health effects of
1,2,4-trichlorofaenzene, there is little evidence of adverse health
effects resulting from exposure to the low levels of 1,2,4-t-richloro-
benzene believed to occur in the environment. None of the animal
studies, however, provided sufficient data for extrapolating estimates
of dose-response relationships to humans.
Animal data indicate that 1,2,4-trichlorobenzene is slowly absorbed
from the gut, skin and lung, and metabolized to phenols, probably via
an arene oxide intermediate. The phenols, in conjugated form, are
excreted, principally via the urine.
Subchronic studies with rhesus monkeys suggested little effect on
the liver, hematological parameters, or clinical ctvemistries at levels
of 25 mg/kg/day orally for 120 days. Signs of toxicity become evident
at 90 mg/kg, with lethality occuring within 20-30 days in animals
given 174 mg/kg/day (Cragg _et_ al. 1978, Smith et al. 1978).
Similar results were reported for rats, rabbits, and dogs exposed by
inhalation to concentrations up to 800 mg trichlorobenzene/m3, 7 hrs/day, 5
days/week for 30 exposures (Watanabe et_ al^. 1978). Experimental hepatic'
porphyria (which is reversible when exposure ceases) has been induced
in rats given 730 mg/kg/day 1,2,4-trichlorobenzene by gavage for 15
days (Rimington and Ziegler 1963), but not in rats given 200 mg/kg
daily for 120 days (Carlson 1977).
7-1
-------
There were reports of human eye and respiratory irritation occurring
at atmospheric concentrations of 1,2,4-trichlorobenzene of 24 mg/m3, but
not at 19 mg/m-5 (Rowe 1975). There were no other human or animal data
available.
7.1.2 Routes of Exposure
7.1.2.1 Inhalation
Inhalation of ambient air is not expected to expose humans to signif-
icant quantities of 1,2,4-trichlorobenzene. When released to the atmos-
phere as a result of industrial activity, the concentration of 1,2,4-
trichlorobenzene is rapidly decreased fay photodegradation of dry deposi-
tion (fallout). Consequently it does not persist in ambient air long
enough to be detected or to be inhaled by humans for any length of time.
One study sampled the air at the point of emissions release from two
chemical plants, detecting 1,2,4-trichlorobenzene concentrations around
100 ng/m3 (Pellizzari 1978). However, following rapid dilution, the
resulting concentration would be far less in the human environment in
a community with such a 1,2,4-trichlorobenzene emitting facility.
Levels of 1,2,4-trichlorobenzene in the ambient atmosphere are
far below the no-apparent-effect-level in rats of 24 mg/m3 for 7
hours a day for a 5-day week reported in Watanabe ££_al. (1978).
Therefore inhaled 1,2,4-trichlorobenzene is not likely~to constitute
a human health risk due to the low levels found in the ambient atmos-
pheric environment.
The reported human eye irritations occurred following exposure
to 24 mg/m3 but not to 19 mg/m3. These levels are orders of magnitude
above the worst case atmospheric exposure at the point of emission
from a chemical plant. Consequently, risk of human eye irritation
due to exposure to 1,2,4-trichlorobenzene at ambient air levels can
be considered to be negligible.
7.1.2.2 Ingestion
There are no reliable dose-response data for ingestion of 1,2,4-
trichlorobenzene in drinking water and food. The only identified signif-
icant route of ingested 1,2,4-trichlorobenzene is from drinking water .
The compound has been identified in several U.S. community water supplies
at a median concentration of 0.02 ug/1 (U.S. EPA undated). One study
identified 1,2,4-trichlorobenzene at the site of a spill and found that
it persisted in nearby groundwater; however, no other data could be
found to indicate what concentrations occur in groundwaters tapped for
drinking supplies or at what frequency. Finally, 1,2,4-trichlorobenzene
has been detected in high concentrations in selected industrial effluent
waters (see Section 4.3). If drinking water intakes were located nearby
or downstream of effluents, associated drinking waters might be contaminated
with 1,2,4-trichlorobenzene; there are no data to evaluate this potential
exposure.
7-2
-------
Because of the lack of information on human health effects levels and
limited exposure data, the human health risk associated with ingestion
of 1,2,4-trichlorobenzene cannot be evaluat'ed at this time.
7.1.3 Conclusions
The risk associated with exposure to 1,2,4-trichlorobenzene is
uncertain for ingestion of contaminated drinking water. The exposure
associated with inhalation of 1,2,4-trichlorobenzene is expected to be
minimal due to the extremely low levels occurring in ambient air; however,
risk associated with inhalation can not be reliably determined on the
basis of existing animal data.
7.2 NON-HUMAN RISK
The available data on concentrations of 1,2,4-trichlorobenzene in
environmental media and on effects levels for aquatic biota are extremely
limited. Although some chronic and acutely toxic effects of 1,2,4-tri-
chlorobenzene have been observed, the concentrations eliciting these
responses are generally well above those reported for ambient waters.
A water quality criterion has not been established by the U.S. EPA to
protect freshwater aquatic life because of the insufficiency of data
(U.S. EPA 1980a); it must be noted, however, that most data that is
available is-from studies performed outside the United States and is
based in part on effects data for other chlorinated benzenes. The limited
monitoring data suggest that a level of 30 yg/1 (suggested criterion in the
Soviet Union) is rarely exceeded in ambient waters, but may be exceeded in
the vicinity of industrial effluent discharges.
7.2.1 Exposure - -
In order to determine the potential risk to aquatic organisms due
to 1,2,4-trichlorobenzene exposure, it is necessary to compare effects
levels to ambient levels. The STORET Water Quality System and data
available in the literature indicate that the majority of ambient concen-
trations detected in waters were below 10 ug/1 for ambient waters (U.S.
EPA 1980b). There were roughly 10 ambient observations between 100 and
1000 pg/1, i.e..above the threshold for chronic effects, all of which
occurred in the Missouri basin.
Higher concentrations of 1,2,4-trichlorobenzene were reported in the
vicinity of industrial effluents. Maximum observations were in the range
of 47 yg/1 to 270 yg/1, the latter of which is in the range of producing
adverse effects to organisms (see Section 4.3). There are no data that
indicate that the compound persists for a significant period of time in
surface waters. In fact much of the compound presumably volatilizes
quite rapidly. No fish kills have been reported in any areas through-
out the U.S. (U.S. EPA, personal communication 1980).
7-3
-------
7.2.2 Aquatic Effects and Risk Considerations
The threshold levels for toxic effects for different species range
from 1 to 50 mg/1, with only one value below that at 0.45 mg/1. Chronic
effects were observed at levels in the range of 200-700 ug/1 (U.S. EPA
1980). Much of the data on adverse effects to aquatic organisms are
extrapolated from the effects experienced by various species to other
chlorinated benzenes. Therefore, it is difficult to evaluate the risk
posed to specific species by exposure to 1,2,4-trichlorobenzene. However,
if the limited monitoring data are assumed to be representative of wide-
spread environmental conditions, there appears to be little overlap
between levels in surface water and effects levels for chlorinated
benzenes.
Trichlorobenzene seems to bioaccumulate to a greater extent than
some other chlorinated hydrocarbons, but the bioconcentration factor
of 182 is not high enough to be considered significant. Since the com-
pound is depurated fairly quickly (<1 day half-life) , residues do not
appear to be a problem. Overall, aquatic systems are not considered
at risk due to exposure to 1,2,4-trichlorobenzene.
7-4
-------
REFERENCES
Carlson, G.P. Chlorinated benzene induction of hepatic porphyria. Ex-
perientia 33(12):1627-1629; 1977.
Cragg. S.T.; Wolfe, G.F.; Smith, C.C. Toxicity of 1,2,4-trichloroben-
zene in rhesus monkeys: comparison of two in vivo methods for estima-
ting P-450 activity. Toxicol. Appl. Pharmacol. 45(1):340; 1978. (Ab-
stract) .
Pellizzari, E.D. Quantification of chlorinated hydrocarbons in pre-
viously collected air samples. EPA 450/3-78-112; 1978.
Rimington, C.; Zeigler, G. Experimental porphyria in rats induced by
chlorinated benzenes. Biochem. Pharmacol. 12:1387-1397; 1963.
Rowe. Written communication; April 1975. (As cited by U.S.EPA 1980)
Smith, C.C.; Tardiff, R.G. Metabolic characteristics of 1,2,4-trichloro-
benzene. Plaa, G.L. and Duncan, W.A.M., eds. Proceedings of the first
international congress on toxicology. New York: Academic Press; 1978:
p.566 (poster presentation).
U.S. Environmental Protection Agency (U.S. EPA) National Organics
Monitoring Survey (NOMS). Washington, DC: Office of Water Supply;
U.S. EPA; undated.
U.S. Environmental Protection Agency (U.S. EPA). Ambient Water Quality
Criteria for Chlorinated Benzenes. Report No. EPA 440/5-80-028.
Washington, DC: Criteria and Standards Division, Office of Water
Regulations and Standards; 1980a.
U.S. Environmental Protection Agency (U.S. EPA) STORET. Washington,
DC: Monitoring and Data Support Division, U.S. Environmental Protection
Agency; 1980b.
Watanabe, P.G.; Kociba, R.J.; Hefner, R.E. Jr.; Yakel, H.O.; Leong, B.K.J.
Subchronic toxicity studies of 1,2,4-trichlorobenzene in experimental
animals. Toxicol. Appl. Pharmacol. 45(1)332-333; 1978. (Abstract)
7-5
-------
APPENDIX A. ASSUMPTIONS REGARDING ENVIRONMENTAL RELEASES
NOTE 1: There were two U.S. producers of 1,2,4-trichlorobenzene
in 1979: Standard Chlorine of Delaware, Inc. in Deleware City and Dow
Chemical Company in Midland, Michigan (Davis, 1980; Dickson, 1980). A
Standard Chlorine plant official stated that their plant produced
2,880 kkg of 1,2,4-trichlorobenzene (Davis, 1980). In a report sub-
mitted to the EPA (and based on the assumption that one-half of the
l,2,3-trich1orobenzene/l,2,4-trichlorobenzene mixed isomer batch was
1,2,4-trichlorobenzene), a total of 8,187 metric tons of 1,2,4-tri-
chlorobenzene were imported and produced; 45 kkg were withdrawn from
inventory (Hull and Co., 1980). According to calculations presented
in Note 5 in Appendix A, 886 kkg of 1,2,4-trichlorobenzene were
imported in 1979. Taking all of these numbers into account, Dow
probably produced 8,187 - (2,880 + 886) or 4,221 kkg and the two
producers together manufactured 8,187-886 or 7,301 metric tons of
1,2,4-trichlorobenzene for the year 1979.
The U.S. 1,2,4-trichlorobenzene production statistics for
1968-1973 are as follows:
Quantity (kkq)
Year
1968
1969
1970
1971
1972
1973
Source: EPA, 1977a
Production
4,928
6,901
4,238
5,004
7,039
12,820
Sales
5,020
6,045
4,322
5,501
7,105
11,881
NOTE 2: Based on process description, approximately 1% of the
total quantity of tar produced via the batch process for chlorobenzene
manufacture (the same process for which 1,2,4-trichlorobenzene is
made) is 1,2,4-trichlorobenzene; see Section 3.2.1.1 for further
details.
A-l
-------
NOTE 3: Based on the assumption that all of the 1,2,4-trichloro-
benzene used as dye carriers is initially sent to water where it may
or may not be removed by in-plant treatment procedures; see Section
3.3.1.1 Table 3-2 and Tables B-l and B-2 (Appendix B) for further
details.
NOTE 4: According to Lapp and Sadler (1976), one-half of the
release from electrical apparatus impregnation is to air (fugitive
emissions) and one-half is discharged to water (handling).
NOTE 5: In 1978, import values of 6,739,685 Ibs for all
trichloro-, dichloro-, and monochlorobenzene were reported (Harris,
1980). Assuming one-third of this value represents the quantity of
tricnlorobenzenes imported domestically in 1979, then 2,245,561 Ibs or
1,019 kkg were brought into this country for that year.
In 1974 a total of 1,693 kkg of trichlorobenzenes were imported
of which 10 kkg «1%), 427 kkg (25%), and 1,256 kkg (74%) were 1,3,5-,
mixed isomers-, and 1,2,4-trichlorobenzene, respectively (EPA, 1977a).
If one-half of the trichlorobenzene mixed isomers was 1,2,4-tnchloro-
benzene, then the total amount of 1,2,4-trichlorobenzene domestically
imported in 1974 was about 1,470 kkg, which is 87% of the total
trichlorobenzene import value. Therefore, if 87% of the total amount
of trichlorobenzene imported into the U.S. in 1979 was 1,2,4-tri-
chlorobenzene, then: 1,019 kkg (0.87) or 886 kkg of 1,2,4-tnchloro-
benzene were imported in 1979.
NOTE 6: Based on data presented by Lewis (1975), approximately
7% (531 kkg) of the total quantity of 1,2,4-trichlorobenzene used in
1973 was consumed by miscellaneous users. For purposes of this
report, miscellaneous uses inlcude all uses other than dye carriers,
pesticide intermediates and functional fluids; i.e., miscellaneous
uses include: degreasing agents, septic tank and drain cleaners, wood
preservatives and abrasive formulations (Hull and Co., 1970; EPA,
1977a). Based on 1979 use patterns for 1,2,4-trichlorobenzene,
approximately 80% (424 kkg), 5% (27 kkg), 5% (27 kkg), 10% (53 kkg),
and <1% (5 kkg) of the total quantity consumed by miscellaneous users
(530 kkg) was used in degreasing agents (i.e., 382 kkg by electronic
wafer stripper and 42 kkg for engine cleaners), septic tank cleaners,
drain cleaners, wood preservatives and abrasive formulations,
respectively (Hull and Co., 1980). Environmental releases from their
uses are as follows:
A-2
-------
Quantity Used Environmental Releases3
(kkg) Water Land Air
POTU Surface
Degreasing
Agents
electronics b 382 29 67 190
engines 42 42
Cleaners
septic tank 27 27
drain 27 27
Wood
Preservatives c 53 1
Abrasives <5
a) Numbers may not add due to rounding; a blank space means <1 kkg
released.
b) Electronic wafer cleaning operations used 382 kkg of 1,2,4-tri-
chlorobenzene, of which, an estimated 191 kkg were contained in
contaminated waste solvents, of which, 10 kkg were destroyed by
incineration, 86 kkg reclaimed, 67 kkg disposed to land, and
29 kkg discharged to POTWs (EPA, 1979c).
c) Fifty-two of the 53 kkg of 1,2,4-trichlorobenzene used in wood
preservatives were retained in the wood (Richards, 1980).
NOTE 7: 1,2,4-Trichlorobenzene is also formed by other methods:
reacting-benzene hexachloride with calcium hydroxide at 100°C and
dehydrohalogenation of oC-benzene hexachloride by pyridine (Hardie,
1964). According to an EPA report (1977a), hexachlorobenzene, when
reacted with alcoholic caustic potash, will produce 1,2,4-trichloro-
benzene. However, because hexachlorobenzene has not been commercially
A-3
-------
produced for sale since 1976, direct production of 1,2,4-trichloro-
benene rom hexachlorobenzene.most likely is an obsolete process (SRI,
1980).
NOTE 8: When chlorobenzene is chlorinated, three
dichlorobenzene isomers result in the following percentages:
Monochlorobenzene C12>ortho (30%) + para (70%) + meta(trace)
catalyst
NOTE 9; 1,2,4-Trichlorobenzene is manufactured by a batch
process as shown in Figure B-l (Lowenheim and Moran, 1975). Dry
benzene is charged into a glass- or lead-lined stirred tank reactor.
Either iron turnings or anhydrous ferric chloride are used as a
catalyst and remain in the chlorinator after each batch. Chlorine is
added to the reactor at such a rate to keep the temperature between
40° and 60°C. If the monochlorobenzene is the desired product, the
reaction temperature is maintained at approximately 40°C and about 60%
of the stoichiometeric requirement of chlorine used. If poly-sub-
stituted chlorobenzenes are desired in addition to monochlorobenzene,
the reaction is run at a temperature of 55 to 60°C for approximately
six hours.
Hydrogen chloride is recovered by scrubbing with chlorobenzene to
remove organic contaminants and absorbing the product gas in a
suitable absorption system to give hydrochloric acid. The chloro-
benzene product is washed in a stirred reactor with an aqueous
solution of sodium hydroxide (10% by weight). A sludge, rich in
dichlorobenzenes, settles and is withdrawn for subsequent dis-
tillation. After separation of the aqueous layer, the crude reaction
product is distilled.
The first two fractions are recycled for further processing. The
third fraction contains chlorobenzene which is collected and sent to
storage. The fourth fraction, containing primarily dichloro- and
1,2,4-trichlorobenzene, is collected and fractionally distilled to
separate the j)- and £-dichlorobenzene isomers from 1,2,4-trichloro-
benzene (EPA, 1977a; Lowenheim and Moran, 1975).
NOTE 10: A particularly important class of inadvertent sources
is found within the chemical industry. Chemical species do not react
via single reaction pathway; depending on the nature of the reactive
intermediate there are a variety of pathways which lead to a series of
reaction products. Often one pathway may be greatly favored over all
others, so that by appropriate process design and control of reaction
conditions, manufacturers can maximize product yield while minimizing
waste production. Therefore, manufacture of a chemical product
A-4
-------
consists of three steps: (1) combination of reactants under suitable
conditions, to yield the desired product; (2) separation of the
product from the reaction matrix (e.g., by-products, coproducts and
reaction solvents); and (3) final purification of the product. The
wastes produced from these separations thus constitute additional
sources of chemicals to the environment.
NOTE 11; Even if hexachlorobenzene was manufactured in 1979,
1,2,4-trichlorobenzene most likely would not be released from this
source for reasons discussed below. Hexachlorobenzene is usually
produced by one of three methods: (1) manufacture of perchloro-
ethylene (contained within by-product tar), (2) reacting benzene (or
chlorobenzene) with chlorine (Figures B2 and B3) or (3) treatment of
hexachlorocyclohexane isomers with sufuryl chloride. Because the
by-product tar from method (1) is known to contain 80% hexachloro-
benzene and 10% hexachlorobutadiene, and the remaining 10% .is recycled
to the process, it is doubtful any 1,2,4-trichlorobenzene would be
released to the environment (EPA, 1975b). Method (2) most likely does
'not release 1,2,4-trichlorobenzene because partially chlorinated
benzenes in this process are recycled back to the primary reactors.
Furthermore, method (3) could not act as an inadvertent source for
1,2,4-trichlorobenzene because lower chlorinated benzenes are not
produced in the process (EPA, 1975b).
NOTE 12: Tetrachlorobenzenes were readily detectable in soil
samples collected from a site where tetrachlorobenzene-containing
transformer fluid had'been spilled seven months earlier. Although a
fraction of the tetrachlorobenzenes had been lost (presumably by
evaporation and runoff, particularly from the top inch of the affected
soil), 43% of the original tetrachlorobenzenes was present in the next
lower inch (EPA, 1980b).
NOTE 13: In 1977, approximately 500-4,500 kkg of penthachloro-
benzene were produced and converted to pentachloronitrobenzene, a soil
fungicide and seed disinfectant. Also, 400 kkg of pentachlorobenzene
were produced inadvertently as by-product during the manufacture of
other chlorinated benzenes and disposed as waste (Dow, 1979).
NOTE 14: Hexachlorobenzene does not undergo photochemical
reactions in the atmosphere and is neither hydrolyzed in aqueous
solutions nor broken down by physical, chemical or biological degrada-
tion processes occuring in the environment (EPA, 1979a).
NOTE 15: The degradation of lindane to 1,2,4-trichlorobenzene
and other compounds by insects, rabbits, and wheat plants has been
recognized by Menzie (1969), Karapally and his associates (1973) and
A-5
-------
Balba and Saha (1974), respectively. Furthermore, lindane is broken
down in soil, presumably by a variety of microorganisms (Mathur and
Saha, 1975; Tu, 1976).
NOTE 16; In most textile mills, the 1,2,4-trichlorobenzene dye
carrier is only used when specific (usually darker) hues are required.
The amount of trichlorobenzene contained in a dye carrier formulation
ranges from 10-90% of the total formulation and from <1 - 10% by
weight, once added to the dye bath.
NOTE 17: During 1977 and 1978 the EPA collected wastewaters from
50 U.S. textile mills where 1,2,4-trichlorobenzene was found only in
those samples originating from wool scouring, woven fabric finishing
(simple and complex processing with desizing) and knit fabric finish-
ing operations (EPA, 1979b). This report also discussed 1,165 U.S.
wet processing textile mills where 520 performed the aforementioned
operations as follows:
Percent of total
wool scouring 3
woven fabric finishing* 43
knit fabric finshing 54
Total 520 100
In 1979 an estimated 3,490 kkg of 1,2,4-trichlorobenzene were
used by domestic textile mills where it is assumed that all of this
1,2,4-trichlorobenzene was discharged to water. If an EPA survey
(1979b) is representative of the entire textile industry (which was
estimated to consist of 2,000 wet processing mills), and each
operation contributes an equal quantity of 1,2,4-trichlorobenzene to
wastewaters, then 3, 43, and 54 percent of the total 3,490 kkg used
(or 105, 1,501, and 1,885 kkg of 1,2,4-trichlorobenzene) were
discharged to water by wool scouring, woven fabric finishing, and knit
fabric finishing operations, respectively.
NOTE 18: Dicamba » 3,6-dichloro-2-methoxybenzoic acid; stirofos=
2-chloro-l-(2,4,5-trichlorophenyl)-ethenyl dimethyl phosphate; and
trichlorodinitrobenzene - l,2,4-trichloro-3,5-dinitrobenzene (Sittig,
1977).
NOTE 19; 1,2,4-Trichlorobenzene is used in the production of
dicamba as follows: 1,2,4-trichlorobenzene (250 grams, 1.4 mols) and
sodium hydroxide (250 grams, 6.3 mols) were dissolved in 1,100 cc of
methanol and the solution was charged into a rocking bomb of 4 liter
*Assuming two thirds of the total number of woven fabric finishing
mills surveyed performed simple and complex processing with
desizing.
A-6
-------
capacity. The solution heated in the sealed bomb at 190°C for 4
hours, during which time the pressure in the bomb rose to 600 psi.
The reaction mixturte was removed from the cooled bomb, and the
residual solid sodium salt of the phenol was dissolved in hot water,
and the solution filtered. The combined aqueous and methanolic
solutions were then acidified with hydrochloric acid whereupon an oil
separated which was taken up in ether. Drying of the ether solution
over magnesium sulphate, filtration, and removal of the ether in vacuo
produced an oily residue which on distillation under 2mm pressure gave
2 grams (90% of theory) of an oil boiling at 70°C. The oil solidified
on standing to solid 2,5-dichlorophenol (B.pt. 57°C), a compound
further processed to make dicamba (Richter, 1961; Sittig, 1977).
Stirofos is made by the reaction of trimethyl phosphate with
pentachloroacetophenone — the compound that 1,2,4-trichlorobenzene is
incorporated into (Sittig, 1977). To 88 parts of aluminum chloride
was added 109 parts of 1,2,4-trichlorobenzene. To this slurry, 88
parts of dichloroacetyl chloride was added over a period of ten
minutes with stirring. The mixture then was heated slowly to 90°C
where it was held for 4 hours. Decomposition of the complex resulted
when the reaction mixture was poured onto a mixture of ice and
hydrochloric acid. The resulting mixture was extracted with ether and
the organic phase thus obtained was washed successively with dilute
hydrochloric acid, water, dilute sodium bicarbonate solution and
finally with saturated salt (NaCl) solution. The solvent was
evaporated and the residue was distilled to give 134 parts (77% yield)
of 2,2,2',4',5'-pentachloroacetophenone (B.pt. 103-105°C; Phillips
and Word, 1963; Sittig, 1977).
Trichlorodinitrobenzene is made from 1,2,4-trichlorobenzene and
other compounds as follows: a reactor equipped with an agitator,
water-cooled condenser, thermometer, liquid feed device, and an
external heating and cooling device was charged with 385 parts of a
nitrating agent consisting of 18% nitric acid, 73% sulfuric acid and
9% sulfur trioxide. This nitrating agent was wanned to 35°C with
stirring and 90.7 parts of 1,2,4-trichlorobenzene added over a period
of 30 minutes. The reaction temperature was maintained at 110°C for
6.5 hours at which time the water content of the spent acid was 3%.
The reaction mixture was poured into a large volume of water,
precipitating l,2,4-trichloro-3,5-dinitrobenzene in 90.5% yield
(Dittmar, 1956; Sittig, 1977).
NOTE 20: As of 1/1/79, dicamba was only made by Northwest
Industries, Inc., a subsidiary of Velsicol Chemical Corporation; and
Shell Chemical Company was the only producer of stirofos (as of
A-7
-------
Note 21; The addition of 1,2,4-trichlorobenzene to dielectric
fluids not only increases the viscosity and pour point of the liquid,
but also the rate of its impregnation into the apparatus (Lapp and
Sadler, 1976).
NOTE 22: Stripping of electronic wafers is assumed to have been
a cold cleaning operation which involved spraying, dipping, and/or .
wiping the pieces to be cleaned with solvent at room temperature.
NOTE 23: Production of 1,2,4-trichlorobenzene-containing
grinding wheels involves the follpwing steps: (1) an abrasive (often
aluminum oxide, silicon carbide and/or diamond grains) is mixed with a
relatively small quantity of liquid (in which 1,2,4-trichlorobenzene
is a portion or all of this liquid); (2) to (1) is added a resinous
powder; (3) blend (1) and (2) both mechanically and manually; (4) pour
the mix into a mold and press to initially "set" the wheel; and (5)
cure the mix at 160 C for 48 hours (Richards, 1980).
A-8
-------
APPENDIX B. PROCESS SPECIFIC DATA ON 1,2,4-
TRICHLOROBENZENE RELEASES
B-l
-------
Table B-l Quantities of 1.2.4-Trlchlorobenzene-Containing Hastes Released
to the Environment from Met Processing Textile Hills 1n 1979 (kkg)*
None
Preliminary
Biological
(or equivalent)
Advanced
Unknown
Total
S of iota
Hastes'
35
29
35
0
0
Wool Scouring0
1 quantity released9
(T) Mater land air
37 6 31
30 12 18
38 3 1 17h 17h
0
0
105k 21 50 17 17
Woven Fabric Finishing*1
» of total ^^
Wastes' (T)
41
22
25
1
11
615
330
375
15
165
1.501k
Quantity released9
Water land air
D 1
41 574
34 296
28 10 169h 169h
15'
132^ 33
235 913 184 169
Knit Fabric Finishing'
I Of total quant
Wastes' TO TTlai
51
21
20
2
6
961
396
377
38
113
1.885k
D
66
21
,2J
283 1
Ity released
ter land
~l
895
396
17 169h
38*
21
.225 207
1°
afr
169h
169
a) Number may not add due to rounding.
b) Preliminary refers to: neutralization, screening, equalization, heat exchange, disinfection, primary sedimentation, and/or floatation; biological or
eau vaUn7refer$ to: aerated and unaerated lagoons, biological filtration, activated sludge, chemical coagulation/flocculatlon without preceedlng
bio og cal treatment advanced refers to: activated carbon! chemical coagulation following biological tre.tment ozonatlon. f» —'"« •«- — "•«-
and mimbrane processes; unknown means the type of treatment was not determined but for purposes of th s able ««n refertono
estimated removal efficiencies for 1.2.4-trtchlorobenzene per treatment practice are: none • Ot; preliminary « 01. biological
9?he
, . got
(or equivalent) 901.
c)
advanced • 1001; and unknown • OS.
To Include: raw wool scouring, heavy scour, carbonizing, bleaching and spinning.
,.
denim.
d) To Include: simple processing - plecedyeing and printing of upholstery fabric, sheets, blankets and'towels andI complex ft™?"1"8^'"el ^nd
deslzlng. scouring, bleaching, mercerizing.-piUcedyelng. weaving, printing and yarn dyeing of finished fabric, sheets, sorting, apparel and
e) To include: simple processing - scouring, piecedyeing of apparel, outerware and car upholstery fabrics and complex processing - scouring, bleaching.
printing and plecedyeing of apparel and finished fabrics.
f) Based on the assumption that all mills produce equal quantities of 1.2.4-trichlorobenzene wastes where all is initially ^•^h^dUtribution""of
of total 1.2,4-trichlorobenzene-contalnlng waste generated by mills with both this operation and type of treatment Is based upon the distribution of
treatment practices utilized by the surveyed wet processing textile mills that discharged 1.2.4-trlchlorobenzene (EPA. 1979b).
g) (T) - tolal quanllly of 1.2.4-trlchlorobenzene released to water, land and air combined; D - 1.2.4-trlchlorobenzene waste J'wtly d'$ch«r9Jd *°
9) waters. . - 1.2,4-trlchlorobenzen. waste Indirectly discharged via publicly .owned treatment wor s; 05 50 and 1 885 metric ton of 1.4-
-Uho ea
with no treat
h)
1)
j)
k)
Wdiers. I " I .£ ,*-irii.iuuiuueii*CMC waaic ni«ii «*.t. 17 .41 »*.•••• ^ww *.» rwH..«.j ........ -.— ------- .; . |T»
benzene were used and released by wool scouring, woven fabric finishing, and knit fabric finishing operations, where (T)
1 of total wastes per type of treatment times the total amount of 1.2.4-trlchlorobenzene waste per operat on. I.e.. (for ">°I
ment): (T) • .35 (143) • 50 kkg; T was calculated by multiplying (T) times the 1 of wastes not captured (based on control device ef('ole^y • 'J«
quantity of 1.2.4-trichlorobeniene wastes distributed between 0 and I was based upon the discharge practices of the U.S. wet processing textile mills
surveyed In an EPA report (1979b) and shown In Figure B2. Appendix B.
Based on the assumption that the 1.2.4-trichlorobenzene removed during biological (or equivalent) treatment was divided equally between land and air
sinks.
Based on the assumption that the 1.2.4-trlchlorobenzene wastes removed during advanced treatment were sent to land.
Based on the assumption that the 1.2.4-trlchlorobenzene contained In these wastewalers. which were disposed of by an unknown means (see "U" on
Table B2 In Appendix B) was sent to surface waters.
Values calculated by multiplying the total quantity of 1.2.4-trichlorobenzene released by the textile Industry In 1979 (3.<89 kkg) times the percent of
textile mills performing that operation which releases 1.2.4-trlchlorobenzene; I.e.. 17 wool scouring mills of the total 520 mills
releasing 1.2.4-trichlorobenzene - 31; 31 of 3.489 • 105 kkg. see Table B-2 In Appendix B for total number of mills per pertinent operation.
Source: EPA. 1979b.
-------
to
M111 No Biological or Treatment Totals
Operation Treatment Preliminary Equivalent Advanced Unclassified
D I D I D I D I D I U' D I All Mills
Wool Scouring
Woven Fabric Finishing13
1
6
5
84
2
5
3
43
4
40
2
15
0 0
3 0
0
0
0 0
5 20
7 10
54 148
17
221
Knit Fabric Finishing
Fabric Processing 10 135 0 59 31 .24 7003 13 48 221 282
Tota1 17 224 7 105 75 41 10 0 0 8 33 109 379 520
a) D refers to direct discharger, I to Indirect dischargers, and U to unclsslfled mill
Preliminary - neutralization, screening, equalization, heat exchange,
disinfection, primary sedimentation, and/or flotation
Biological - aerated and unaerated lagoons, biological filtration, activated
or sludge, chemical coagulation/flocculatlon without proceeding
Equivalent biological treatment
Advanced - activated carbon, chemical coagulation following biological
treatment, ozonation, filtration, ion exchange, membrane
processes, etc.
b) Includes simple processing and complex processing plus deslzlng.
Source: EPA, 1979b.
-------
VENT
CHLOROBENZENE.
BENZENE-
CATALYST'
CHLORINE
BENZENE and WATER
BENZENE and CHLOROBENZENE
HLOROBENZENE
FRACTIONATING
COLUMN
DICHLORO- and TRICHLOROBENZENES
X
3 1 CHLOROBENZENES
FRACTIONATING
COLUMN
1.2,4-TRICHLOROBENZENE
•1,2.4-TRICHLOROBENZENE
FRACTIONATING COLUMN
COLUMN
Figure B-l. Batch Production of Chlorobenzenes
Y
TAR
a) Ferric chloride or Iron filings.
Source: Lowenheim and Moran, 1975; EPA, 1977a.
B-4
-------
01
Cl,
PRIMARY
REACTOR
SCRUBBER
PARTIALLY CHLORINATED
BENZENES
COOLER and
CRYSTALLIZER
PACKAGING
SHIPMENT
HC1
CENTRIFUGE
PURIFICATION
and DRYING
PACKAGING
SHIPMENT o
HEXACHLOROBENZENE
SEPARATION
of LOWER
CHLOROBENZENES
PURIFICATION
and DRYING
PACKAGING
SHIPMENT of
PENTACHLOROBENZENE
Figure B-2. Production Schematic for Pentachlorobenzene by Chlorlnatlon
of Benzene or Chlorobenzene (EPA, 1975b)
-------
BY-PRODUCT
HC1
Cl,
PRIMARY REACTOR
with FeCK as
CATALYST
SEPARATION
DRYING
PACKAGING
SCRUBBER
CRYSTALLIZER
CENTRIFUGE
PARTIALLY CHLORINATED BENZENES
DRYING and
PACKAGING
SHIPMENT OF
PENTACHLOROBENZENE
SHIPMENT OF
HEXACHLOROBENZENE
Figure B-3. Production Schematic for Hexachlorobenzene by Chlorlnatlon
of Benzene and Chlorobenzenes (EPA, 1975b)
-------
APPENDIX C. ESTIMATION OF VOLATILIZATION FROM WATER
Volatilization from water can be estimated using procedures des-
cribed in the literature. The mathematical modeling of volatilization
involves interphase exchange coefficients that depend on the chemical
and physical properties of the chemical in question, the presence of
other pollutants, and the physical properties of the water body and
atmosphere above it. Basic factors controlling volatilization are sol-
ubility, molecular weight, and the vapor pressure of the chemical and
the nature of the air-water interface through which the chemical must
pass.
Because of the lack of data for most chemicals, however, estimates
of volatilization rates from surface waters on the basis of mathematical
data and laboratory measurements are necessarily of unknown precision.
Still, comparisions of experimental results with theoretical predictions
indicate that these predictive techniques generally agree with actual
processes within a factor of two or three in most cases.
The methods described below have been used to estimate volatiliza-
tion from natural surface water (see Section 4.12). The EXAMS model
has been used to investigate behavior in natural surface water bodies,
however, this method was not used as input to EXAMS. An input para-
meter similar to the reaeration coefficients described below is used
in EXAMS to estimate volatilization; this value was obtained elsewhere
(SRI 1980).
The following procedures were used to estimate the volatilization
rate of a chemical. Minimum data required are:
• Chemical properties—vapor pressure, aqueous solubility,
molecular weight;
• Environmental characteristics—wind speed, current speed,
depth of water body;
(1) Find or estimate the Henry's Law constant H from:
H « P/S atm-m^/mole
where P = vapor pressure, atm
S = aqueous solubility, mole/m^.
When calculating H as a ratio of vapor pressure to solubility, it is
essential to have these data at about the same temperature and appli-
cable to the same physical state of the compound. Data for pure com-
pounds should be used because vapor pressure and solubilities of mix-
tures may be suspect.
C-l
-------
(2) If H<3 :< 10 atm-m /mole, volatilization can be considered unim-
portant as an intemedia transfer mechanism and no further calculations
ara necessary.
(3) If H>3 x 10 atm-m /mole, the chemical can be considered volatile.
The nondimensional Henry's Law constant H' should be determined from:
H' - H/RT . (2)
R • gas constant, 8
T » temperature, K.
where R • gas constant, 8.2 x 10 atm-m /mole K
At 20C (293K) RT is 2.4 x 10~2 atm-m3/mole.
(4) The liquid phase exchange coefficient kjj, must be estimated. This
coefficient is from a method that analyzes the volatilization process
on the basis of a two-layer film, one water and one air, which separates-
the bulk of the water body from the bulk of the air (Liss and Slater 1974)
For a low molecular weight compound (1565, ki can be estimated from equations developed by Southworth
(1979). Because this method is different from Equation (3), the esti-
mated values may vary. If the average wind speed is ^.1.9 m/sec,
T0.969'
/
(
\
zw>
where V « water'current velocity, m/sec
curr
Z * depth of water body, m.
If wind speed is >1.9 m/sec and <5 m/sec,
0.526 (V . ,-1.9) ,. ...
» wind cm/hr (5)
where V . , * windspeed, m/sec.
wind r
If wind speed is >5 m/sec, liquid phase exchange coefficients are diffi-
cult to predict and may range up to 70 ca/hr.
(5) The gas phase exchange coefficient must be estimated. This too is
based on the two-film analysis. For a compound of 15
-------
Slater (1974),
k - 3000 yi3/M ca/hr (6)
If M>65 (Southworth 1979),
kg - 1137.5 (Vwind + V) iiTM cm/hr . . (7)
(6) The Henry's Law constant and gas and liquid phase exchange coefficients
are used to compute the overall liquid phase mass transfer coefficient,
KL (Liss and Slater 1974), which is an indicator of the volatilization
H'k
csn/hr
(7) The volatilization rate constant k is:
v
hr'1
where Z is in cm.
(8) Assuming a first order volatilization process, the concentration
in the stream in the absence of continuing inputs at the location at
which volatilization occurs, is
c(t) - cQe" vc
where c(t) » pollutant concentration in the water column at time t
CQ " initial pollutant concentration in the water column.
(9) The half-life in the water column for che pollutant volatilizing at
a first order rate is:
0.69 Z .
TJs ~F - hr- (ID
L»
Another method for computing k for highly volatile chemicals with •
H>10~3 atin-m^/mole is based onvreaeration rate coefficients (Smith and
Bomberger 1977, Smith et al. 1979, Tsivoglou 1967). The following data
are required:
• Ratio of reaeration rate of chemical to that of water,
• Reaeration rate of oxygen for water bodies in the environment
or steamflow parameters (velocity, stream bed slope, depth).
C-3
-------
If the oxygen raaeration rata is known for a given water body or type
of water body., the volatilization rate constant for the pollutant can
be estimated from (Smith and 3onfaerger 1979) :
(kC ) - CkC/k°). , (k°) (12)
^ v 'env v v'lah v' env
whera kc - first order volatilization rate constant for the
V particular chemical (hr~^) ;
k° - reaeratioa rate constant for oxygen '(hr ) ;
env* designates values applicable to environmental
situations ;
lab - designates laboratory -measured values.
This equation applies particularly to rivers. For lakes and ponds, the
following equation may be more accurate:'
(kc)
Ckc/k°) J'? (k°) (13)
Typical values of (kv)env are given in the literature and reported by
v env v v lab v env
values of (
Smith et_ al, (1979):
Water Body (k$)anv, hr~
. Pond -0.0046-0.0096
River 0.008, 0.04-0.39
Lake 0.004-0.013
The values for ponds and lakes are speculative and depend on depth.
Mackay and Yuen (1979) present the equations listed below that cor-
relate k^ with river flow velocity, depth, and slope:
Tsivoglou-Wa-llace: k° - 638 ~
Parkhurst-Pomeroy: k° - 1.08 (1 + 0.17 F2) (Vcurrs)0'0375 hr~L (15)
Churchill et al. : k° - 0.00102V^5 z"3'085 s'°'823 hr'1 (16)
If no slope data are available:
Isaccs-Gundy: k° - O.iaSVZ"1'5 hr"1 (17)
1 O -^ 1
Langbein-Durum: k° » 0.2^1 V Z hr" (18)
3 v curr
C-4
-------
where V » river flow velocity (m/s);
s * river bed slope • m drop/m run (nondimensional);
Z - river depth (m);
2
g a acceleration of gravity -9,8 m/s .
Because none of the foregoing is clearly superior to the others,
the best approach is probably to use all that are applicable and then
average the results (Cohen e_t^ ail. 1978). For a river 2 m deep, flowing
at 1 m/sec, the reaeration rate is estimated as 0.042/hr. (k^/k0,)1 ,
is known for some chemicals (see Table C-l). If a (k^/k^)]^ value3
is not known, one for a similar high-volatility chemical should be
a reasonable substitute.
In principle, k£ is the same as (KL/Z); however, due to the use
of (k^)env, k£ has the depth and other water body characteristics
embedded within it. Therefore, no adjustment is required for use in
the first order volatilization equation.
C-5
-------
TABLE C-l
MEASURED REAE5ATIOM
COEFFICIENT
RATIOS
FOR HIGH VOLATILITY COMPOUNDS
Compound
Chloroform
1,1-Dichloroethane
Oxygen
Benzo [b] thiophene
Dibenzothiophene
Benzene
Carbon dioxide
Carbon tetrachloride
Dicyclopentadiene
Ethylene
Krypton
Propane
Radon
Tetrachloroethyene
Trichloroethylene
H
atm-m3/
• mole
3.8 x 10- 3
5.8 x 10-3
7.2 x 10~2
2.7 x 10-"1
4.4 x lO'1*
5.5 x 10-3
2.3 x 10-2
8.6
8.3 x 10-3
1 x 10~2
Measured
kc/k°
V V
.57 ± .02
.66 ± .11
.71 ± .11
1.0
.38 ± .08
.14
.57 ± .02
.89 ± .03
.63 ± .07
.54 ± .02
.87 ± .02
.82 ± .08
.72 ± .01
.70 t .08
.52 ± .09
.57 ± .15
Source: Smith ec al. (1979).
C-6
-------
REFERENCES
Cohen, T.; Cocchio, W. ; Mackay, D. Laboratory study of liquid phase
controlled volatilization rates in presence of wind waves. Environ.
Sci. Techno!. 12:553-558; 1978.
Liss, P.S.; Slater, P.G. Flux of gases across the air-sea interface.
Nature 247:181-184; 1974.
T K Volatilization rates of organic contaminants
Uth Canadian Syuposi^: Water PoUution
Research Canada; 1979.
1977.
Sci. Technol.; 1979.
Toxicol. 21:507-514; 1979.
Stanford Research Institute (SRI) . Estimates of physical-chemical
properties of organic priority pollutants. Preliminary draft.
Washington, DC: Monitoring and Data Support Division, U.S. Environ-
mental Protection Agency; 1980.
Tsivoglu, E.C. Tracer measurements of stream "aeration Washington,
DC. Fed. Water Pollut. Contr. Admin.; 1967. PB 229Z3-BA.
Verschueren, K. Handbook of environmental data on organic chemicals.
New York, NY: Van Nostrand Reinhold; 1977.
C-7
------- |